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The Register of Clinical Technologists (RCT) is a voluntary professional register for clinical technologists and practitioners specialising in the practical application of physics, engineering and technology to clinical practice in the UK. Registrants work in NHS hospitals, private health care, academic institutions and the medical device industry.
== History ==
The Register was formed in August 2000 as the Voluntary Register of Clinical Technologists (VRCT), with the aim of protecting the public by advocating statutory, professional regulation for Clinical Technologists. Despite the name change to RCT, membership of the register remains voluntary to this day and the number of active members is falling. Management of the Register was undertaken by members of the Institute of Physics and Engineering in Medicine (IPEM), the Association of Renal Technologists and the Institution of Incorporated Engineers (now the Institution of Engineering and Technology).
At its formation, the Register was designed to be a platform for the Clinical Technologist profession's campaign for statutory regulation with the then Health Professions’ Council (HPC). However, in 2011 the UK Government Command Paper ‘Enabling Excellence: Autonomy and Accountability for Health and Social Care Staff’ stated that extensions to statutory regulation "will only be considered where there is a compelling case on the basis of a public safety risk and where assured voluntary registers are not considered sufficient to manage this risk", and indicated that the way forward would be via assured voluntary registration. This was subsequently developed into a system of Accredited Registers administered by the Profession Standards Authority (PSA).
In 2013, at the request of the VCRT Management Panel, the management of the register was integrated into the professional work of IPEM, in order to provide a firmer footing for an application to the PSA to become an Accredited Register. In 2015, the Register was successful in achieving accreditation. In Dec 2023, the PSA is carrying out a re-accreditation assessment of the RCT.
In January 2024 the cost of yearly membership of the register has risen from £30 in 2023 to £48 per year.
== References ==
== External links ==
PSA | Wikipedia/Register_of_Clinical_Technologists |
An engineering technologist is a professional trained in certain aspects of development and implementation of a respective area of technology. An education in engineering technology concentrates more on application and less on theory than does an engineering education. Engineering technologists often assist engineers; but after years of experience, they can also become engineers. Like engineers, areas where engineering technologists can work include product design, fabrication, and testing. Engineering technologists sometimes rise to senior management positions in industry or become entrepreneurs.
Engineering technologists are more likely than engineers to focus on post-development implementation, product manufacturing, or operation of technology. The American National Society of Professional Engineers (NSPE) makes the distinction that engineers are trained in conceptual skills, to "function as designers", while engineering technologists "apply others' designs". The mathematics and sciences, as well as other technical courses, in engineering technology programs, are taught with more application-based examples, whereas engineering coursework provides a more theoretical foundation in math and science. Moreover, engineering coursework tends to require higher-level mathematics including calculus and calculus-based theoretical science courses, as well as more extensive knowledge of the natural sciences, which serves to prepare students for research (whether in graduate studies or industrial R&D) as opposed to engineering technology coursework which focuses on algebra, trigonometry, applied calculus, and other courses that are more practical than theoretical in nature and generally have more labs that involve the hands-on application of the topics studied.
In the United States, although some states require, without exception, a BS degree in engineering at schools with programs accredited by the Engineering Accreditation Commission (EAC) of the Accreditation Board for Engineering and Technology (ABET), about two-thirds of the states accept BS degrees in engineering technology accredited by the Engineering Technology Accreditation Commission (ETAC) of the ABET, in order to become licensed as professional engineers. States have different requirements as to the years of experience needed to take the Fundamentals of Engineering (FE) and Professional Engineering (PE) exams. A few states require those sitting for the exams to have a master's degree in engineering. This education model is in line with the educational system in the United Kingdom where an accredited MEng or MSc degree in engineering is required by the Engineering Council (EngC) to be registered as a Chartered Engineer. Engineering technology graduates with can earn an MS degree in engineering technology, engineering, engineering management, construction management, or a National Architectural Accrediting Board (NAAB)-accredited Master of Architecture degree. These degrees are also offered online or through distance-learning programs at various universities, both nationally and internationally, which allows individuals to continue working full-time while earning an advanced degree.
== Nature of the work ==
Engineering technologists are more likely to work in testing, fabrication/construction or fieldwork, while engineers generally focus more on conceptual design and product development, with considerable overlap (e.g., testing and fabrication are often integral to the overall product development process and can involve engineers as well as engineering technologists).
Engineering technologists are employed in a wide array of industries and areas including product development, manufacturing and maintenance. They may become managers depending upon the experience and their educational emphasis on management. Entry-level positions relating in various ways to product design, product testing, product development, systems development, field engineering, technical operations, and quality control are common for engineering technologists. Most companies generally make no distinction between engineers and engineering technologists when it comes to hiring.
== Education and accreditation ==
Beginning in the 1950s and 1960s, some post-secondary institutions in the U.S. and Canada began offering degrees in engineering technology, focusing on applied study rather than the more theoretical studies required for engineering degrees. The focus on applied study addressed a need within the scientific, manufacturing, and engineering communities, as well as other industries, for professionals with hands-on and applications-based engineering knowledge. Depending on the institution, associate's or bachelor's degrees are offered, with some institutions also offering advanced degrees in engineering technology.
In general, an engineering technologist receives a broad range of applied science and applied mathematics training, as well as the fundamentals of engineering in the student's area of focus. Engineering technology programs typically include instruction in providing support to specific engineering specialties. Information technology is primarily involved with the management, operation, and maintenance of computer systems and networks, along with an application of technology in diverse fields such as architecture, engineering, graphic design, telecommunications, computer science, and network security. An engineering technologist is also expected to have had some coursework in ethics.
In 2001, Professional organizations from different countries have signed a mutual recognition agreement called the Sydney Accord, which represents an understanding that the academic credentials of engineering technologists will be recognized in all signatory states. The recognition given engineering technologists under the Sydney Accord can be compared to the Washington Accord for engineers and the Dublin Accord for engineering technicians. The Engineering Technologist Mobility Forum (ETMF) is an international forum held by signatories of the Sydney Accord to explore mutual recognition for experienced engineering technologists and to remove artificial barriers to the free movement and practice of engineering technologists amongst their countries. ETMF can be compared to the Engineers Mobility Forum (EMF) for engineers.
Graduates acquiring an associate degree, or lower, typically find careers as engineering technicians. According to the United States Bureau of Labor Statistics: "Many four-year colleges offer bachelor's degrees in engineering technology and graduates of these programs are hired to work as entry-level engineers or applied engineers, but not technicians." Engineering technicians typically have a two-year associate degree, while engineering technologists have a bachelor's degrees.
=== Canada ===
In Canada, the new occupational category of "technologist" was established in the 1960s, in conjunction with an emerging system of community colleges and technical institutes. It was designed to effectively bridge the gap between the increasingly theoretical nature of engineering degrees and the predominantly practical approach of technician and trades programs. Provincial associations may certify individuals as a professional technologist (P.Tech.), certified engineering technologist (C.E.T.), registered engineering technologist (R.E.T.), applied science technologist (AScT), or technologue professionel (T.P.). These provincial associations are constituent members of Technology Professionals Canada (TPC), which accredits technology programs across Canada, through its Technology Accreditation Canada (TAC). Nationally accredited engineering technology programs range from two to three years in length, depending on the province, and often require as many classroom hours as a 4-year degree program.
=== United States ===
In the United States, the U.S. Department of Education or the Council for Higher Education Accreditation (CHEA) are at the top of the educational accreditation hierarchy. The U.S. Department of Education acknowledges regional and national accreditation and CHEA recognizes specialty accreditation. One technology accreditation is currently recognized by CHEA: The Association of Technology, Management and Applied Engineering (ATMAE). CHEA recognizes ATMAE for accrediting associate, baccalaureate, and master's degree programs in technology, applied technology, engineering technology, and technology-related disciplines delivered by national or regional accredited institutions in the United States. As of March 2019, ABET withdrew from CHEA recognition
The National Institute for Certification in Engineering Technologies (NICET) awards certification at two levels, depending on work experience: the Associate Engineering Technologist (AT) and the Certified Engineering Technologist (CT). ATMAE awards two levels of certification in technology management: Certified Technology Manager (CTM) and Certified Senior Technology Manager (CSTM). ATMAE also awards two levels of certification of manufacturing specialist: Certified Manufacturing Specialist (CMS) and Certified Senior Manufacturing Specialist (CSMS). In 2020, ATMAE announced offering the Certified Controls Engineer (CCE) and Certified Senior Controls Engineer (CSCE) professional certifications. While the CTM, CMS, and CCE certifications are obtained through examination, the CSTM, CSMS and CSCE require industry experience and continuous improvement via the obtainment of professional development units (PDUs).
The American Society of Certified Engineering Technicians (ASCET) is a membership organization that issues Certified Member certifications to engineering technicians and engineering technologists. Professional engineers are issued Registered Member certification.
=== United Kingdom ===
The United Kingdom has a decades-long tradition of producing engineering technologists via the apprenticeship system. UK engineering technologists have always been designated as "engineers", which in the UK is used to describe the entire range of skilled workers and professionals, from tradespeople through to the highly educated Chartered Engineer. In fact up until the 1960s professional engineers in the UK were often referred to as "Technologists" to distinguish them from scientists, technicians, and craftsmen. The modern term for an engineering technologist is "incorporated engineer" (IEng), although since 2000 the normal route to achieving IEng is with a bachelor's or honors degree in engineering or technology. Modern technical apprenticeships would normally lead to the engineering technician (EngTech) professional qualification and, with further studies at higher apprenticeship level, an IEng. Since 2015, the Universities and Colleges Admissions Service (UCAS) has introduced engineering degree (bachelors and masters) apprenticeships. The title "incorporated engineer" is protected by civil law. Prior to the title "incorporated engineer", UK technologists were known as "technician engineers" a designation introduced in the 1960s.
In the United Kingdom, an incorporated engineer is accepted as a "professional engineer", registered by the EngC, although the term "professional engineer" has no legal meaning in the UK and there are no restrictions on the practice. In fact, anyone in the UK can call themselves an "engineer" or "professional engineer" without any qualifications or proven competence in engineering; and most UK skilled trades are sometimes referred to as "professional" or "accredited" engineers. Examples are "Registered Gas Engineer" (gas installer) or "Professional Telephone Engineer" (phone line installer or fault diagnosis).
Incorporated engineers are recognized internationally under the Sydney Accord as engineering technologists. One of the professional titles recognized by the Washington Accord for engineers in the United Kingdom is the chartered engineer. The incorporated engineer is a professional engineer as recognized by the EngC of the United Kingdom. The European designation, as demonstrated by the prescribed title under 2005/36/EC, is "engineer". The incorporated engineer operates autonomously and directs activities independently. They do not necessarily need the support of chartered engineers, because they are often acknowledged as full engineers in the UK (but not in Canada or the U.S.). The United Kingdom incorporated engineer may also contribute to the design of new products and systems.
The chartered engineer and incorporated engineer, whilst often undertaking similar roles, are distinct qualifications awarded by the EngC, with Chartered Engineer (CEng) status being the terminal engineering qualification.
Incorporated engineers currently require an IEng-accredited bachelors or honors degree in engineering (prior to 1997 the B.Sc. and B.Eng. degrees satisfied the academic requirements for "chartered engineer" registration), a Higher National Certificate or diploma, City and Guilds of London Institute higher diploma/full technological cert diploma, or a Foundation Degree in engineering, plus appropriate further learning to degree level, or an NVQ4 or SVQ4 qualifications approved for the purpose by a licensed engineering institution.
The academic requirements must be accompanied by the appropriate peer-reviewed experience in employment—typically 4 years post qualification. In addition to the experience and academic requirements, the engineering candidate must have three referees (themselves CEng or IEng) who vouch for the performance of the individual being considered for professional recognition. There are a number of alternative ways to achieve IEng status for those that do not have the necessary qualifications for applicants, but who can clearly show they have achieved the same level as those with qualifications, including:
writing a technical report, based upon their experience and demonstrate their knowledge and understanding of engineering principles;
earning the City and Guilds graduate diploma (bachelors level) and a postgraduate diploma (masters level) accredited by the Institution of Mechanical Engineers (IMechE), Institution of Engineering and Technology (IET) and Institution of Civil Engineers (ICE);
following a work-based learning program;
or taking an academic program specified by the institution to which they are applying.
=== Germany – European Union ===
==== Engineering technologist / state-certified engineer ====
The engineering technologist (state-certified technician; German: Staatlich geprüfter Techniker) are vocational (non-academic) qualifications at the tertiary level in Germany. The degree is governed by the framework agreement of trade and technical schools (resolution of the Standing Conference of the Ministers of Education and Cultural Affairs of the states in the Federal Republic of Germany of 7 November 2002 in its respective applicable version) and is recognised by all states of the Federal Republic of Germany. It is awarded after passing state examinations at state or state-recognised technical school or academies (German: Fachschule/Fachakademie). Through the Vocational Training Modernisation Act (12.12.2019), state-certified engineers are also allowed to hold the title Bachelor Professional in Technik as of 1 January 2020.
To be eligible for the engineering technologist examination, candidates must fulfill the following requirements: completion of one of the school systems (Hauptschule, Realschule, Gymnasium), an apprenticeship of at least two years duration, one year of completed professional work experience and attendance of an educational program with a course load of 2400–3000 hours, usually completed within two years, full-time, or 3.5–4 years, part-time, at vocational colleges.
==== State-certified technicians/engineers in the EU directives ====
As of 31 January 2012, state-certified engineers, state-certified business managers and state-certified designers are at level 6-bachelor in the European Qualifications Framework (EQF), equivalent to a bachelor's degree. As such, the engineering technologist constitutes an advanced entry qualification for German universities and in principle permits entry into any undergraduate academic-degree program.
The qualifications are listed in EU Directives as recognised, regulated professions in Germany and the EU. Annexes C and D were added to Council Directive 92/51/EEC as a second general system for the recognition of professional education and training to supplement Directive 89/48/EEC.
Institutions involved included the federal government (in Germany, the Federal Ministry of Education and Research and the Federal Ministry of Economics and Technology), EU Standing Conference and Economic Ministerial Meeting of Countries, the German Chamber of Crafts, the Confederation of German Employers' Associations, German Chambers of Industry and Commerce, Confederation of German Trade Unions, and the Federal Institute for Vocational Application. These government institutions agreed on a common position regarding the implementation of the EQF and a German qualifications framework (DQR).
European Union law and other documents considered to be public include:
Annexes C and D to Council Directive 92/51/EEC on a second general system for the recognition of professional education and training to supplement Directive 89/48/EEC
EU Directive 2005L0036-EN 01.01.2007
ANNEX III list of regulated education and training referred to in the third subparagraph of Article 13(2)
== See also ==
National Council of Examiners for Engineering and Surveying
American Society for Engineering Education
UNESCO-UNEVOC
Practical engineer
Drafter
== References ==
== Further reading ==
Sastry, M.K.S.; Clement K. Sankat; Harris Khan; Dave Bhajan (2008). "The need for technologists and applied technology programs: an experience from Trinidad and Tobago". International Journal of Management in Education. 2 (2): 222. doi:10.1504/IJMIE.2008.018393.
Sastry, M.K.S.; C.K. Sankat; D. Exall; K.D. Srivastava; H. Khan; B.Copeland; W. Lewis; D.Bhajan (April 2007). "An Appraisal of Tertiary Level Institutional Collaboration and Joint Degree Programs in Trinidad and Tobago". Latin American and Caribbean Journal of Engineering Education. 1 (1): 27–34. ISSN 1935-0295. Retrieved 4 October 2010. | Wikipedia/Incorporated_engineer |
In systems engineering and requirements engineering, a non-functional requirement (NFR) is a requirement that specifies criteria that can be used to judge the operation of a system, rather than specific behaviours. They are contrasted with functional requirements that define specific behavior or functions. The plan for implementing functional requirements is detailed in the system design. The plan for implementing non-functional requirements is detailed in the system architecture, because they are usually architecturally significant requirements.
In software architecture, non-functional requirements are known as "architectural characteristics". Note that synchronous communication between software architectural components entangles them, and they must share the same architectural characteristics.
== Definition ==
Broadly, functional requirements define what a system is supposed to do and non-functional requirements define how a system is supposed to be. Functional requirements are usually in the form of "system shall do <requirement>", an individual action or part of the system, perhaps explicitly in the sense of a mathematical function, a black box description input, output, process and control functional model or IPO model. In contrast, non-functional requirements are in the form of "system shall be <requirement>", an overall property of the system as a whole or of a particular aspect and not a specific function. The system's overall properties commonly mark the difference between whether the development project has succeeded or failed.
Non-functional requirements are often called the "quality attributes" of a system. The emergent properties of a system are classified as non-functional requirements. Other terms for non-functional requirements are "qualities", "quality goals", "quality of service requirements", "constraints", "non-behavioral requirements", or "technical requirements". Informally these are sometimes called the "ilities", from attributes like stability and portability. Qualities—that is non-functional requirements—can be divided into two main categories:
Execution qualities, such as safety, security and usability, which are observable during operation (at run time).
Evolution qualities, such as testability, maintainability, extensibility and scalability, which are embodied in the static structure of the system.
It is important to specify non-functional requirements in a specific and measurable way.
== Classification of non-functional requirements ==
Common non-functional classifications, relevant for all types of systems include
Performance
Reliability, availability, maintainability and safety
Scalability
Testability
Specific type of systems explicitly enumerate categories of non-functional requirements in their standards
Hardware systems
Embedded systems
Safety-critical systems
Software systems
== Examples ==
A system may be required to present the user with a display of the number of records in a database. This is a functional requirement. How current this number needs to be, is a non-functional requirement. If the number needs to be updated in real time, the system architects must ensure that the system is capable of displaying the record count within an acceptably short interval of the number of records changing.
Sufficient network bandwidth may be a non-functional requirement of a system. Other examples include:
== See also ==
ISO/IEC 25010:2011
Consortium for IT Software Quality
ISO/IEC 9126
FURPS
Requirements analysis
Usability requirements
Non-Functional Requirements framework
Architecturally Significant Requirements
SNAP Points
== References ==
== Notes ==
== External links ==
Petter L. H. Eide (2005). "Quantification and Traceability of Requirements". CiteSeerX 10.1.1.95.6464.
Dalbey, John. "Nonfunctional Requirements". Csc.calpoly.edu. Retrieved 3 October 2017.
"Modeling Non-Functional Aspects in Service Oriented Architecture" (PDF). Cs.umb.edu. Archived from the original (PDF) on 24 July 2011. Retrieved 3 October 2017.
"Non-Functional Requirements: Do User Stories Really Help?". Methodsandtools.com. Retrieved 3 October 2017.
"Non-Functional Requirements Be Here - CISQ - Consortium for IT Software Quality". it-cisq.org. Retrieved 3 October 2017.
""Do Software Architectures Meet Extra-Functional or Non-Functional Requirements?"". 19 November 2020. | Wikipedia/Nonfunctional_requirement |
Modular Function Deployment (MFD) is a method for creating modular product architectures, based on research performed at KTH Royal Institute of Technology in the 1990s. As a result of said research, the company Modular Management was registered in 1996, offering consultancy services centered on the MFD method.
With a modular product architecture, companies can offer a wide range of products and services without increasing complexity, since modules and module variants, like blocks of LEGO, can be configured in many different ways. The MFD method ensures that each module has functional, strategic and customer-centric value and can be combined with other modules through standardized interfaces. A modular product architecture can enable mass customization, where customers configure and order personalized—rather than ready-made—products and services.
== Five Steps ==
MFD consists of five steps and is often illustrated as a circle to emphasize that it is an iterative process.
Clarify Customer Needs
Identify Functions and Solutions
Propose Modules and Interfaces
Define Variants and Configurations
Confirm Architecture Feasibility
== References ==
Gunnar Erixon: "Modular Function Deployment – A Method for Product Modularisation", Ph.D. Thesis. The Royal Institute of Technology, Stockholm, 1998. TRITA-MSM R-98-1, ISSN 1104-2141, ISRN KTH/MSM/R-98/1-SE.
"Application of the Modular Function Deployment Tool on a pressure regulator", Gilles Clemen / Rotarex Automotive S.A., Lintgen/Luxembourg
== External links ==
Modular Function Deployment | Wikipedia/Modular_function_deployment |
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP). Early versions of this networking model were known as the Department of Defense (DoD) model because the research and development were funded by the United States Department of Defense through DARPA.
The Internet protocol suite provides end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received. This functionality is organized into four abstraction layers, which classify all related protocols according to each protocol's scope of networking. An implementation of the layers for a particular application forms a protocol stack. From lowest to highest, the layers are the link layer, containing communication methods for data that remains within a single network segment (link); the internet layer, providing internetworking between independent networks; the transport layer, handling host-to-host communication; and the application layer, providing process-to-process data exchange for applications.
The technical standards underlying the Internet protocol suite and its constituent protocols are maintained by the Internet Engineering Task Force (IETF). The Internet protocol suite predates the OSI model, a more comprehensive reference framework for general networking systems.
== History ==
=== Early research ===
Initially referred to as the DOD Internet Architecture Model, the Internet protocol suite has its roots in research and development sponsored by the Defense Advanced Research Projects Agency (DARPA) in the late 1960s. After DARPA initiated the pioneering ARPANET in 1969, Steve Crocker established a "Networking Working Group" which developed a host-host protocol, the Network Control Program (NCP). In the early 1970s, DARPA started work on several other data transmission technologies, including mobile packet radio, packet satellite service, local area networks, and other data networks in the public and private domains. In 1972, Bob Kahn joined the DARPA Information Processing Technology Office, where he worked on both satellite packet networks and ground-based radio packet networks, and recognized the value of being able to communicate across both. In the spring of 1973, Vinton Cerf joined Kahn with the goal of designing the next protocol generation for the ARPANET to enable internetworking. They drew on the experience from the ARPANET research community, the International Network Working Group, which Cerf chaired, and researchers at Xerox PARC.
By the summer of 1973, Kahn and Cerf had worked out a fundamental reformulation, in which the differences between local network protocols were hidden by using a common internetwork protocol, and, instead of the network being responsible for reliability, as in the existing ARPANET protocols, this function was delegated to the hosts. Cerf credits Louis Pouzin and Hubert Zimmermann, designers of the CYCLADES network, with important influences on this design. The new protocol was implemented as the Transmission Control Program in 1974 by Cerf, Yogen Dalal and Carl Sunshine.
Initially, the Transmission Control Program (the Internet Protocol did not then exist as a separate protocol) provided only a reliable byte stream service to its users, not datagrams. Several versions were developed through the Internet Experiment Note series. As experience with the protocol grew, collaborators recommended division of functionality into layers of distinct protocols, allowing users direct access to datagram service. Advocates included Bob Metcalfe and Yogen Dalal at Xerox PARC; Danny Cohen, who needed it for his packet voice work; and Jonathan Postel of the University of Southern California's Information Sciences Institute, who edited the Request for Comments (RFCs), the technical and strategic document series that has both documented and catalyzed Internet development. Postel stated, "We are screwing up in our design of Internet protocols by violating the principle of layering." Encapsulation of different mechanisms was intended to create an environment where the upper layers could access only what was needed from the lower layers. A monolithic design would be inflexible and lead to scalability issues. In version 4, written in 1978, Postel split the Transmission Control Program into two distinct protocols, the Internet Protocol as connectionless layer and the Transmission Control Protocol as a reliable connection-oriented service.
The design of the network included the recognition that it should provide only the functions of efficiently transmitting and routing traffic between end nodes and that all other intelligence should be located at the edge of the network, in the end nodes. This end-to-end principle was pioneered by Louis Pouzin in the CYCLADES network, based on the ideas of Donald Davies. Using this design, it became possible to connect other networks to the ARPANET that used the same principle, irrespective of other local characteristics, thereby solving Kahn's initial internetworking problem. A popular expression is that TCP/IP, the eventual product of Cerf and Kahn's work, can run over "two tin cans and a string." Years later, as a joke in 1999, the IP over Avian Carriers formal protocol specification was created and successfully tested two years later. 10 years later still, it was adapted for IPv6.
DARPA contracted with BBN Technologies, Stanford University, and the University College London to develop operational versions of the protocol on several hardware platforms. During development of the protocol the version number of the packet routing layer progressed from version 1 to version 4, the latter of which was installed in the ARPANET in 1983. It became known as Internet Protocol version 4 (IPv4) as the protocol that is still in use in the Internet, alongside its current successor, Internet Protocol version 6 (IPv6).
=== Early implementation ===
In 1975, a two-network IP communications test was performed between Stanford and University College London. In November 1977, a three-network IP test was conducted between sites in the US, the UK, and Norway. Several other IP prototypes were developed at multiple research centers between 1978 and 1983.
A computer called a router is provided with an interface to each network. It forwards network packets back and forth between them. Originally a router was called gateway, but the term was changed to avoid confusion with other types of gateways.
=== Adoption ===
In March 1982, the US Department of Defense declared TCP/IP as the standard for all military computer networking. In the same year, NORSAR/NDRE and Peter Kirstein's research group at University College London adopted the protocol. The migration of the ARPANET from NCP to TCP/IP was officially completed on flag day January 1, 1983, when the new protocols were permanently activated.
In 1985, the Internet Advisory Board (later Internet Architecture Board) held a three-day TCP/IP workshop for the computer industry, attended by 250 vendor representatives, promoting the protocol and leading to its increasing commercial use. In 1985, the first Interop conference focused on network interoperability by broader adoption of TCP/IP. The conference was founded by Dan Lynch, an early Internet activist. From the beginning, large corporations, such as IBM and DEC, attended the meeting.
IBM, AT&T and DEC were the first major corporations to adopt TCP/IP, this despite having competing proprietary protocols. In IBM, from 1984, Barry Appelman's group did TCP/IP development. They navigated the corporate politics to get a stream of TCP/IP products for various IBM systems, including MVS, VM, and OS/2. At the same time, several smaller companies, such as FTP Software and the Wollongong Group, began offering TCP/IP stacks for DOS and Microsoft Windows. The first VM/CMS TCP/IP stack came from the University of Wisconsin.
Some of the early TCP/IP stacks were written single-handedly by a few programmers. Jay Elinsky and Oleg Vishnepolsky of IBM Research wrote TCP/IP stacks for VM/CMS and OS/2, respectively. In 1984 Donald Gillies at MIT wrote a ntcp multi-connection TCP which runs atop the IP/PacketDriver layer maintained by John Romkey at MIT in 1983–84. Romkey leveraged this TCP in 1986 when FTP Software was founded. Starting in 1985, Phil Karn created a multi-connection TCP application for ham radio systems (KA9Q TCP).
The spread of TCP/IP was fueled further in June 1989, when the University of California, Berkeley agreed to place the TCP/IP code developed for BSD UNIX into the public domain. Various corporate vendors, including IBM, included this code in commercial TCP/IP software releases. For Windows 3.1, the dominant PC operating system among consumers in the first half of the 1990s, Peter Tattam's release of the Trumpet Winsock TCP/IP stack was key to bringing the Internet to home users. Trumpet Winsock allowed TCP/IP operations over a serial connection (SLIP or PPP). The typical home PC of the time had an external Hayes-compatible modem connected via an RS-232 port with an 8250 or 16550 UART which required this type of stack. Later, Microsoft would release their own TCP/IP add-on stack for Windows for Workgroups 3.11 and a native stack in Windows 95. These events helped cement TCP/IP's dominance over other protocols on Microsoft-based networks, which included IBM's Systems Network Architecture (SNA), and on other platforms such as Digital Equipment Corporation's DECnet, Open Systems Interconnection (OSI), and Xerox Network Systems (XNS).
Nonetheless, for a period in the late 1980s and early 1990s, engineers, organizations and nations were polarized over the issue of which standard, the OSI model or the Internet protocol suite, would result in the best and most robust computer networks.
=== Formal specification and standards ===
The technical standards underlying the Internet protocol suite and its constituent protocols have been delegated to the Internet Engineering Task Force (IETF).
The characteristic architecture of the Internet protocol suite is its broad division into operating scopes for the protocols that constitute its core functionality. The defining specifications of the suite are RFC 1122 and 1123, which broadly outlines four abstraction layers (as well as related protocols); the link layer, IP layer, transport layer, and application layer, along with support protocols. These have stood the test of time, as the IETF has never modified this structure. As such a model of networking, the Internet protocol suite predates the OSI model, a more comprehensive reference framework for general networking systems.
== Key architectural principles ==
The end-to-end principle has evolved over time. Its original expression put the maintenance of state and overall intelligence at the edges, and assumed the Internet that connected the edges retained no state and concentrated on speed and simplicity. Real-world needs for firewalls, network address translators, web content caches and the like have forced changes in this principle.
The robustness principle states: "In general, an implementation must be conservative in its sending behavior, and liberal in its receiving behavior. That is, it must be careful to send well-formed datagrams, but must accept any datagram that it can interpret (e.g., not object to technical errors where the meaning is still clear).": 23 "The second part of the principle is almost as important: software on other hosts may contain deficiencies that make it unwise to exploit legal but obscure protocol features.": 13
Encapsulation is used to provide abstraction of protocols and services. Encapsulation is usually aligned with the division of the protocol suite into layers of general functionality. In general, an application (the highest level of the model) uses a set of protocols to send its data down the layers. The data is further encapsulated at each level.
An early pair of architectural documents, RFC 1122 and 1123, titled Requirements for Internet Hosts, emphasizes architectural principles over layering. RFC 1122/23 are structured in sections referring to layers, but the documents refer to many other architectural principles, and do not emphasize layering. They loosely defines a four-layer model, with the layers having names, not numbers, as follows:
The application layer is the scope within which applications, or processes, create user data and communicate this data to other applications on another or the same host. The applications make use of the services provided by the underlying lower layers, especially the transport layer which provides reliable or unreliable pipes to other processes. The communications partners are characterized by the application architecture, such as the client–server model and peer-to-peer networking. This is the layer in which all application protocols, such as SMTP, FTP, SSH, HTTP, operate. Processes are addressed via ports which essentially represent services.
The transport layer performs host-to-host communications on either the local network or remote networks separated by routers. It provides a channel for the communication needs of applications. UDP is the basic transport layer protocol, providing an unreliable connectionless datagram service. The Transmission Control Protocol provides flow-control, connection establishment, and reliable transmission of data.
The internet layer exchanges datagrams across network boundaries. It provides a uniform networking interface that hides the actual topology (layout) of the underlying network connections. It is therefore also the layer that establishes internetworking. Indeed, it defines and establishes the Internet. This layer defines the addressing and routing structures used for the TCP/IP protocol suite. The primary protocol in this scope is the Internet Protocol, which defines IP addresses. Its function in routing is to transport datagrams to the next host, functioning as an IP router, that has the connectivity to a network closer to the final data destination.
The link layer defines the networking methods within the scope of the local network link on which hosts communicate without intervening routers. This layer includes the protocols used to describe the local network topology and the interfaces needed to effect the transmission of internet layer datagrams to next-neighbor hosts.
== Link layer ==
The protocols of the link layer operate within the scope of the local network connection to which a host is attached. This regime is called the link in TCP/IP parlance and is the lowest component layer of the suite. The link includes all hosts accessible without traversing a router. The size of the link is therefore determined by the networking hardware design. In principle, TCP/IP is designed to be hardware independent and may be implemented on top of virtually any link-layer technology. This includes not only hardware implementations but also virtual link layers such as virtual private networks and networking tunnels.
The link layer is used to move packets between the internet layer interfaces of two different hosts on the same link. The processes of transmitting and receiving packets on the link can be controlled in the device driver for the network card, as well as in firmware or by specialized chipsets. These perform functions, such as framing, to prepare the internet layer packets for transmission, and finally transmit the frames to the physical layer and over a transmission medium. The TCP/IP model includes specifications for translating the network addressing methods used in the Internet Protocol to link-layer addresses, such as media access control (MAC) addresses. All other aspects below that level, however, are implicitly assumed to exist and are not explicitly defined in the TCP/IP model.
The link layer in the TCP/IP model has corresponding functions in Layer 2 of the OSI model.
== Internet layer ==
Internetworking requires sending data from the source network to the destination network. This process is called routing and is supported by host addressing and identification using the hierarchical IP addressing system. The internet layer provides an unreliable datagram transmission facility between hosts located on potentially different IP networks by forwarding datagrams to an appropriate next-hop router for further relaying to its destination. The internet layer has the responsibility of sending packets across potentially multiple networks. With this functionality, the internet layer makes possible internetworking, the interworking of different IP networks, and it essentially establishes the Internet.
The internet layer does not distinguish between the various transport layer protocols. IP carries data for a variety of different upper layer protocols. These protocols are each identified by a unique protocol number: for example, Internet Control Message Protocol (ICMP) and Internet Group Management Protocol (IGMP) are protocols 1 and 2, respectively.
The Internet Protocol is the principal component of the internet layer, and it defines two addressing systems to identify network hosts and to locate them on the network. The original address system of the ARPANET and its successor, the Internet, is Internet Protocol version 4 (IPv4). It uses a 32-bit IP address and is therefore capable of identifying approximately four billion hosts. This limitation was eliminated in 1998 by the standardization of Internet Protocol version 6 (IPv6) which uses 128-bit addresses. IPv6 production implementations emerged in approximately 2006.
== Transport layer ==
The transport layer establishes basic data channels that applications use for task-specific data exchange. The layer establishes host-to-host connectivity in the form of end-to-end message transfer services that are independent of the underlying network and independent of the structure of user data and the logistics of exchanging information. Connectivity at the transport layer can be categorized as either connection-oriented, implemented in TCP, or connectionless, implemented in UDP. The protocols in this layer may provide error control, segmentation, flow control, congestion control, and application addressing (port numbers).
For the purpose of providing process-specific transmission channels for applications, the layer establishes the concept of the network port. This is a numbered logical construct allocated specifically for each of the communication channels an application needs. For many types of services, these port numbers have been standardized so that client computers may address specific services of a server computer without the involvement of service discovery or directory services.
Because IP provides only a best-effort delivery, some transport-layer protocols offer reliability.
TCP is a connection-oriented protocol that addresses numerous reliability issues in providing a reliable byte stream:
data arrives in-order
data has minimal error (i.e., correctness)
duplicate data is discarded
lost or discarded packets are resent
includes traffic congestion control
The newer Stream Control Transmission Protocol (SCTP) is also a reliable, connection-oriented transport mechanism. It is message-stream-oriented, not byte-stream-oriented like TCP, and provides multiple streams multiplexed over a single connection. It also provides multihoming support, in which a connection end can be represented by multiple IP addresses (representing multiple physical interfaces), such that if one fails, the connection is not interrupted. It was developed initially for telephony applications (to transport SS7 over IP).
Reliability can also be achieved by running IP over a reliable data-link protocol such as the High-Level Data Link Control (HDLC).
The User Datagram Protocol (UDP) is a connectionless datagram protocol. Like IP, it is a best-effort, unreliable protocol. Reliability is addressed through error detection using a checksum algorithm. UDP is typically used for applications such as streaming media (audio, video, Voice over IP, etc.) where on-time arrival is more important than reliability, or for simple query/response applications like DNS lookups, where the overhead of setting up a reliable connection is disproportionately large. Real-time Transport Protocol (RTP) is a datagram protocol that is used over UDP and is designed for real-time data such as streaming media.
The applications at any given network address are distinguished by their TCP or UDP port. By convention, certain well-known ports are associated with specific applications.
The TCP/IP model's transport or host-to-host layer corresponds roughly to the fourth layer in the OSI model, also called the transport layer.
QUIC is rapidly emerging as an alternative transport protocol. Whilst it is technically carried via UDP packets it seeks to offer enhanced transport connectivity relative to TCP. HTTP/3 works exclusively via QUIC.
== Application layer ==
The application layer includes the protocols used by most applications for providing user services or exchanging application data over the network connections established by the lower-level protocols. This may include some basic network support services such as routing protocols and host configuration. Examples of application layer protocols include the Hypertext Transfer Protocol (HTTP), the File Transfer Protocol (FTP), the Simple Mail Transfer Protocol (SMTP), and the Dynamic Host Configuration Protocol (DHCP). Data coded according to application layer protocols are encapsulated into transport layer protocol units (such as TCP streams or UDP datagrams), which in turn use lower layer protocols to effect actual data transfer.
The TCP/IP model does not consider the specifics of formatting and presenting data and does not define additional layers between the application and transport layers as in the OSI model (presentation and session layers). According to the TCP/IP model, such functions are the realm of libraries and application programming interfaces. The application layer in the TCP/IP model is often compared to a combination of the fifth (session), sixth (presentation), and seventh (application) layers of the OSI model.
Application layer protocols are often associated with particular client–server applications, and common services have well-known port numbers reserved by the Internet Assigned Numbers Authority (IANA). For example, the HyperText Transfer Protocol uses server port 80 and Telnet uses server port 23. Clients connecting to a service usually use ephemeral ports, i.e., port numbers assigned only for the duration of the transaction at random or from a specific range configured in the application.
At the application layer, the TCP/IP model distinguishes between user protocols and support protocols.: §1.1.3 Support protocols provide services to a system of network infrastructure. User protocols are used for actual user applications. For example, FTP is a user protocol and DNS is a support protocol.
Although the applications are usually aware of key qualities of the transport layer connection such as the endpoint IP addresses and port numbers, application layer protocols generally treat the transport layer (and lower) protocols as black boxes which provide a stable network connection across which to communicate. The transport layer and lower-level layers are unconcerned with the specifics of application layer protocols. Routers and switches do not typically examine the encapsulated traffic, rather they just provide a conduit for it. However, some firewall and bandwidth throttling applications use deep packet inspection to interpret application data. An example is the Resource Reservation Protocol (RSVP). It is also sometimes necessary for Applications affected by NAT to consider the application payload.
== Layering evolution and representations in the literature ==
The Internet protocol suite evolved through research and development funded over a period of time. In this process, the specifics of protocol components and their layering changed. In addition, parallel research and commercial interests from industry associations competed with design features. In particular, efforts in the International Organization for Standardization led to a similar goal, but with a wider scope of networking in general. Efforts to consolidate the two principal schools of layering, which were superficially similar, but diverged sharply in detail, led independent textbook authors to formulate abridging teaching tools.
The following table shows various such networking models. The number of layers varies between three and seven.
Some of the networking models are from textbooks, which are secondary sources that may conflict with the intent of RFC 1122 and other IETF primary sources.
== Comparison of TCP/IP and OSI layering ==
The three top layers in the OSI model, i.e. the application layer, the presentation layer and the session layer, are not distinguished separately in the TCP/IP model which only has an application layer above the transport layer. While some pure OSI protocol applications, such as X.400, also combined them, there is no requirement that a TCP/IP protocol stack must impose monolithic architecture above the transport layer. For example, the NFS application protocol runs over the External Data Representation (XDR) presentation protocol, which, in turn, runs over a protocol called Remote Procedure Call (RPC). RPC provides reliable record transmission, so it can safely use the best-effort UDP transport.
Different authors have interpreted the TCP/IP model differently, and disagree whether the link layer, or any aspect of the TCP/IP model, covers OSI layer 1 (physical layer) issues, or whether TCP/IP assumes a hardware layer exists below the link layer. Several authors have attempted to incorporate the OSI model's layers 1 and 2 into the TCP/IP model since these are commonly referred to in modern standards (for example, by IEEE and ITU). This often results in a model with five layers, where the link layer or network access layer is split into the OSI model's layers 1 and 2.
The IETF protocol development effort is not concerned with strict layering. Some of its protocols may not fit cleanly into the OSI model, although RFCs sometimes refer to it and often use the old OSI layer numbers. The IETF has repeatedly stated that Internet Protocol and architecture development is not intended to be OSI-compliant. RFC 3439, referring to the internet architecture, contains a section entitled: "Layering Considered Harmful".
For example, the session and presentation layers of the OSI suite are considered to be included in the application layer of the TCP/IP suite. The functionality of the session layer can be found in protocols like HTTP and SMTP and is more evident in protocols like Telnet and the Session Initiation Protocol (SIP). Session-layer functionality is also realized with the port numbering of the TCP and UDP protocols, which are included in the transport layer of the TCP/IP suite. Functions of the presentation layer are realized in the TCP/IP applications with the MIME standard in data exchange.
Another difference is in the treatment of routing protocols. The OSI routing protocol IS-IS belongs to the network layer, and does not depend on CLNS for delivering packets from one router to another, but defines its own layer-3 encapsulation. In contrast, OSPF, RIP, BGP and other routing protocols defined by the IETF are transported over IP, and, for the purpose of sending and receiving routing protocol packets, routers act as hosts. As a consequence, routing protocols are included in the application layer. Some authors, such as Tanenbaum in Computer Networks, describe routing protocols in the same layer as IP, reasoning that routing protocols inform decisions made by the forwarding process of routers.
IETF protocols can be encapsulated recursively, as demonstrated by tunnelling protocols such as Generic Routing Encapsulation (GRE). GRE uses the same mechanism that OSI uses for tunnelling at the network layer.
== Implementations ==
The Internet protocol suite does not presume any specific hardware or software environment. It only requires that hardware and a software layer exists that is capable of sending and receiving packets on a computer network. As a result, the suite has been implemented on essentially every computing platform. A minimal implementation of TCP/IP includes the following: Internet Protocol (IP), Address Resolution Protocol (ARP), Internet Control Message Protocol (ICMP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Internet Group Management Protocol (IGMP). In addition to IP, ICMP, TCP, UDP, Internet Protocol version 6 requires Neighbor Discovery Protocol (NDP), ICMPv6, and Multicast Listener Discovery (MLD) and is often accompanied by an integrated IPSec security layer.
== See also ==
BBN Report 1822, an early layered network model
Internetwork Packet Exchange
Fast Local Internet Protocol
List of automation protocols
List of information technology initialisms
List of IP protocol numbers
Lists of network protocols
List of TCP and UDP port numbers
== Notes ==
== References ==
== Bibliography ==
Douglas E. Comer (2001). Internetworking with TCP/IP – Principles, Protocols and Architecture. CET [i. e.] Computer Equipment and Trade. ISBN 86-7991-142-9.
Joseph G. Davies; Thomas F. Lee (2003). Microsoft Windows Server 2003 TCP/IP Protocols and Services. Microsoft Press. ISBN 0-7356-1291-9.
Forouzan, Behrouz A. (2003). TCP/IP Protocol Suite (2nd ed.). McGraw-Hill. ISBN 978-0-07-246060-5.
Craig Hunt (1998). TCP/IP Network Administration. O'Reilly. ISBN 1-56592-322-7.
Maufer, Thomas A. (1999). IP Fundamentals. Prentice Hall. ISBN 978-0-13-975483-8.
Ian McLean (2000). Windows 2000 TCP/IP Black Book. Coriolis Group Books. ISBN 1-57610-687-X.
Ajit Mungale (September 29, 2004). Pro .NET 1.1 Network Programming. Apress. ISBN 1-59059-345-6.
W. Richard Stevens (April 24, 1994). TCP/IP Illustrated, Volume 1: The Protocols. Addison-Wesley. ISBN 0-201-63346-9.
W. Richard Stevens; Gary R. Wright (1994). TCP/IP Illustrated, Volume 2: The Implementation. Addison-Wesley. ISBN 0-201-63354-X.
W. Richard Stevens (1996). TCP/IP Illustrated, Volume 3: TCP for Transactions, HTTP, NNTP, and the UNIX Domain Protocols. Addison-Wesley. ISBN 0-201-63495-3.
Andrew S. Tanenbaum (2003). Computer Networks. Prentice Hall PTR. ISBN 0-13-066102-3.
Clark, D. (1988). "The Design Philosophy of the DARPA Internet Protocols" (PDF). Proceedings of the Sigcomm '88 Symposium on Communications Architectures and Protocols. ACM. pp. 106–114. doi:10.1145/52324.52336. ISBN 978-0897912792. S2CID 6156615. Retrieved October 16, 2011.
Cerf, Vinton G.; Kahn, Robert E. (May 1974). "A Protocol for Packet Network Intercommunication" (PDF). IEEE Transactions on Communications. 22 (5): 637–648. doi:10.1109/TCOM.1974.1092259.
== External links ==
Internet History – Pages on Robert Kahn, Vinton Cerf, and TCP/IP (reviewed by Cerf and Kahn).
T. Socolofsky; C. Kale (January 1991). A TCP/IP Tutorial. Network Working Group. doi:10.17487/RFC1180. RFC 1180. Informational.
The Ultimate Guide to TCP/IP
The TCP/IP Guide – A comprehensive look at the protocols and the procedure and processes involved
A Study of the ARPANET TCP/IP Digest, archived from the original on December 4, 2021 | Wikipedia/Transmission_Control_Protocol/Internet_Protocol |
5G network slicing is a network architecture that enables the multiplexing of virtualized and independent logical networks on the same physical network infrastructure. Each network slice is an isolated end-to-end network tailored to fulfill diverse requirements requested by a particular application.
For this reason, this technology assumes a central role to support 5G mobile networks that are designed to efficiently embrace a plethora of services with very different service level requirements (SLR). The realization of this service-oriented view of the network leverages on the concepts of software-defined networking (SDN) and network function virtualization (NFV) that allow the implementation of flexible and scalable network slices on top of a common network infrastructure.
From a business model perspective, each network slice is administrated by a mobile virtual network operator (MVNO). The infrastructure provider (the owner of the telecommunication infrastructure) leases its physical resources to the MVNOs that share the underlying physical network. According to the availability of the assigned resources, a MVNO can autonomously deploy multiple network slices that are customized to the various applications provided to its own users.
== History ==
The history of network slicing can be tracked back to the late 80s with the introduction of the concept of "slice" in the networking field. Overlay networks provided the first form of network slicing since heterogeneous network resources were combined to create virtual networks over a common infrastructure. However, they lacked a mechanism that could enable their programmability.
In the early 2000s, PlanetLab introduced a virtualization framework that allowed groups of users to program network functions in order to obtain isolated and application-specific slices. The advent of SDN technologies in 2009 further extended the programmability capabilities via open interfaces that enabled the realization of fully configurable and scalable network slices.
In the context of mobile networks, network slicing evolved from the concept of RAN sharing that was initially introduced in LTE standard. Examples of such technology are multi-operator radio access networks (MORAN) and multi-operator core networks (MOCN), which allow network operators to share common LTE resources within the same radio access network (RAN).
== Key concepts ==
The "one-size-fits-all" network paradigm employed in the past mobile networks (2G, 3G and 4G) is no longer suited to efficiently address a market model composed of very different applications like machine-type communication, ultra reliable low latency communication and enhanced mobile broadband content delivery.
Network slicing emerges as an essential technique in 5G networks to accommodate such different and possibly contrasting quality of service (QoS) requirements exploiting a single physical network infrastructure.
The basic idea of network slicing is to "slice" the original network architecture in multiple logical and independent networks that are configured to effectively meet the various services requirements. To quantitatively realize such concept, several techniques are employed:
Network functions: they express elementary network functionalities that are used as "building blocks" to create every network slice.
Virtualization: it provides an abstract representation of the physical resources under a unified and homogeneous scheme. In addition, it enables a scalable slice deployment relying on NFV that allows the decoupling of each network function instance from the network hardware it runs on.
Orchestration: it is a process that allows coordination of all the different network components that are involved in the life-cycle of each network slice. In this context, SDN is employed to enable a dynamic and flexible slice configuration.
=== Impact and applications ===
In commercial terms, network slicing allows a mobile operator to create specific virtual networks that cater to particular clients and use cases. Certain applications - such as mobile broadband, machine-to-machine communications (e.g. in manufacturing or logistics), or smart cars - will benefit from leveraging different aspects of 5G technology. One might require higher speeds, another low latency, and yet another access to edge computing resources. By creating separate slices that prioritise specific resources a 5G operator can offer tailored solutions to particular industries.: 3 Some sources insist this will revolutionise industries like marketing, augmented reality, or mobile gaming, while others are more cautious, pointing to unevenness in network coverage and poor reach of advantages beyond increased speed.
Slicing will be very useful to MVNOs as different use cases can be supported in a layer based on parameters like low latency high speed for video streaming for OTT focused MVNOs, similarly telemetry operations could have lower speed parameter and as on.
Slicing can also enhance service continuity via improved roaming across networks, by creating a virtual network running on physical infrastructure that spans multiple local or national networks; or by allowing a host network to create an optimised virtual network which replicates the one offered by a roaming device's home network.: 6
== Architecture overview ==
Although there are different proposals of network slice architectures, it is possible to define a general architecture that maps the common elements of each solution into a general and unified framework. From a high-level perspective, the network slicing architecture can be considered as composed of two mains blocks, one dedicated to the actual slice implementation and the other dedicated to the slice management and configuration. The first block is designed as a multi-tier architecture composed by three layers (service layer, network function layer, infrastructure layer), where each one contributes to the slice definition and deployment with distinct tasks. The second block is designed as a centralized network entity, generically denoted as network slice controller, that monitors and manages the functionalities between the three layers in order to efficiently coordinate the coexistence of multiple slices.
=== Service layer ===
The service layer interfaces directly with the network business entities (e.g. MVNOs and 3rd party service providers) that share the underlying physical network and it provides a unified vision of the service requirements. Each service is formally represented as service instance, which embeds all the network characteristics in the form of SLA requirements that are expected to be fully satisfied by a suitable slice creation.
=== Network function layer ===
The network function layer is in charge of the creation of each network slice according to service instance requests coming from the upper layer. It is composed of a set of network functions that embody well-defined behaviors and interfaces. Multiple network functions are placed over the virtual network infrastructure and chained together to create an end-to-end network slice instance that reflects the network characteristics requested by the service. The configuration of the network functions are performed by means of a set of network operations that allow management of their full lifecycle (from their placement when a slice is created to their de-allocation when the function provided is no longer needed).
To increase resource usage efficiency, the same network function can be simultaneously shared by different slices at the cost of an increase in the complexity of operations management. Conversely, a one-to-one mapping between each network function and each slice eases the configuration procedures, but can lead to poor and inefficient resource usage.
=== Infrastructure layer ===
The infrastructure layer represents the actual physical network topology (radio access network, transport network and core network) upon which every network slice is multiplexed and it provides the physical network resources to host the several network functions composing each slice.
The network domain of the available resources includes a heterogeneous set of infrastructure components like data centers (storage and computation capacity resources), devices enabling network connectivity such as routers (networking resources) and base stations (radio bandwidth resources).
=== Network slice controller ===
The network slice controller is defined as a network orchestrator, which interfaces with the various functionalities performed by each layer to coherently manage each slice request. The benefit of such network element is that it enables an efficient and flexible slice creation that can be reconfigured during its life-cycle. Operationally, the network slice controller oversees several tasks that provide more effective coordination between the aforementioned layers:
End-to-end service management: mapping of the various service instances expressed in terms of SLA requirements with suitable network functions capable of satisfying the service constraints.
Virtual resources definition: virtualization of the physical network resources in order to simplify the resources management operations performed to allocate network functions.
Slice life-cycle management: slice performance monitoring across all the three layers in order to dynamically reconfigure each slice to accommodate possible SLA requirements modifications.
Due to the complexity of the performed tasks which address different purposes, the network slice controller can be composed by multiple orchestrators that independently manage a subset of functionalities of each layer. To fulfill the service requirements, the various orchestration entities need to coordinate with each other by exchanging high-level information about the state of the operations involved in the slice creation and deployment.
== Slice isolation ==
Slice isolation is an important requirement that allows enforcing the core concept of network slicing about the simultaneous coexistence of multiple slices sharing the same infrastructure. This property is achieved by imposing that each slice's performance must not have any impact on the other slice's performance. The benefit of this design choice is that enhances the network slice architecture in two main aspects:
Slice security: cyber-attacks or faults occurrences affect only the target slice and have limited impact on the life-cycle of other existing slices.
Slice privacy: private information related to each slice (e.g. user statistics, MVNO business model) are not shared among other slices.
== Guaranteeing QoS ==
Slicing has become an important part of 5G networks, but we don't have to forget to guarantee the QoS. Some studies have demonstrated that formulating the problem with the QoS as a stochastic problem, permit us to maximize the average throughput of the AP, while satisfying the constraints related to the QoS.
== Monetizing 5G network slicing ==
Monetizing 5G services faster is one of the topics that interests network operators the most because the costs of building and maintaining 5G networks are high, and it's difficult to predict the demand for 5G services. 5G network slicing is one of the effective ways to offer customized services for different industries such as manufacturing, transportation, and healthcare. Combined with AIOps, ML/AI-driven automation and 5G lifecycle optimization, it can reduce OpEx and increase revenues for network operators.
== 5G core network slicing ==
In the 3GPP 5G core architecture, the user plane and control plane functions are separated. Control plane capabilities, for instance, session management, access authentication, policy management, and user data storage are independent of the user plane functionality. The user plane handles packet forwarding, encapsulation or de-capsulation, and associated transport level specifics. This separation leads to the distribution of the user plane functions close to the edge of network slices (e.g., so as to reduce latency) and to be independent of the control plane. The main 5G core network entities are the Authentication server function (AUSF), Unstructured data storage network function (UDSF), Network exposure function (NEF), NF repository function (NRF), Policy control function (PCF), Unified data management (UDM), Network Slice Selection Function (NSSF), Communication Service Management Function (CSMF), AMF, SMF, and UPF. The AMF (as a function of the CP) controls UEs that have been authenticated to use the services of the operator and manages the mobility of the UEs across the gNBs. The SMF (again part of the CP) manages the sessions of UEs, while AMF transmits the session management messages between the UEs and SMF. UPF (as part of the UP) performs the processing and forwarding of the user data. NSSF (as a function of the CP) is responsible for the management and orchestration of network slices. CSMF (as a function of the CP) translates the requirements of services to requirements relating to network slices. 5G Core network functions can be sliced to support specific services for different UEs. Thanks to the modular nature of the 5G core, the network functions of the 5G core can be split and shared between different network slices to reduce management complexity. In general, we can perform 5G core network slicing in two ways. We can implement dedicated core network functions per network slice. In this architecture, each network slice has a set of completely dedicated core network functions (e.g., AUSF, AMF, SMF, and UDM). The UEs can access various services from network slices and different core networks. Alternatively, we can share some control plane functions between the network slices while others such as user plane functions are slice specific (e.g., UPF). AMF is usually shared by several network slices, while SMF and UPF are usually dedicated to specific network slices. The AMF function will be shared between different network slices in order to reduce the mobility management signaling when the UE uses the services of different network slices simultaneously. For example, UE location management or the control signaling between the UE and the old AMF will be reduced when it will be connected to the new AMF of another network slice. Also, UDM and NSSF are typically shared by all network slices to reduce the management complexity of network slices.
== Network slicing security ==
The emergence of network slicing also exposes novel security and privacy challenges, primarily related to aspects such as network slicing life-cycle security, inter-slice security, intra-slice security, slice broker security, zero-touch network and management security, and blockchain security. Therefore, enhancing the security, privacy, and trust of network slicing has become a key research area toward realizing the true capabilities of 5G. Various security solutions are proposed for resolving the security threats, challenges, and issues of network slicing. These solutions include artificial intelligence based solutions, security orchestration, blockchain based solutions, Security Service Level Agreement (SSLA) and policy based solutions, security monitoring based solutions, slice isolation, security-by-design and privacy-by-design, and offering security as a service.
== See also ==
APN
NGAP
5G
Network virtualization
Software-defined networking
Network orchestration
Network service
5G NR frequency bands
== References == | Wikipedia/5G_network_slicing |
Network segmentation in computer networking is the act or practice of splitting a computer network into subnetworks, each being a network segment. Advantages of such splitting are primarily for boosting performance and improving security.
== Advantages ==
Reduced congestion: On a segmented network, there are fewer hosts per subnetwork and the traffic and thus congestion per segment is reduced
Improved security:
Broadcasts will be contained to local network. Internal network structure will not be visible from outside.
There is a reduced attack surface available to pivot in if one of the hosts on the network segment is compromised. Common attack vectors such as LLMNR and NetBIOS poisoning can be partially alleviated by proper network segmentation as they only work on the local network. For this reason it is recommended to segment the various areas of a network by usage. A basic example would be to split up web servers, databases servers and standard user machines each into their own segment.
By creating network segments containing only the resources specific to the consumers that you authorise access to, you are creating an environment of least privilege
Containing network problems: Limiting the effect of local failures on other parts of network
Controlling visitor access: Visitor access to the network can be controlled by implementing VLANs to segregate the network
== Improved security ==
When a cyber-criminal gains unauthorized access to a network, segmentation or “zoning” can provide effective controls to limit further movement across the network. PCI-DSS (Payment Card Industry Data Security Standard), and similar standards, provide guidance on creating clear separation of data within the network, for example separating the network for Payment Card authorizations from those for Point-of-Service (till) or customer Wi-Fi traffic. A sound security policy entails segmenting the network into multiple zones, with varying security requirements, and rigorously enforcing the policy on what is allowed to move from zone to zone.
== Controlling visitor access ==
Finance and Human Resources typically need access via their own VLAN to their application servers because of the confidential nature of the information they process and store. Other groups of personnel may require their own segregated networks, such as server administrators, security administration, managers and executives.
Third parties are usually required to have their own segments, with different administration passwords to the main network, to avoid attacks via a compromised, less well protected, third party site.
== Means of segregation ==
Segregation is typically achieved by a combination of firewalls and VLANs (virtual local area networks). Software-defined networking (SDN) can allow the creation and management of micro-segmented networks.
== See also ==
Collision domain
Cross-domain solution
Flat network
Network bridge
Network switch
Router (computing)
Unidirectional network
== References == | Wikipedia/Network_segmentation |
A mesh network is a local area network topology in which the infrastructure nodes (i.e. bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data to and from clients.
This lack of dependency on one node allows for every node to participate in the relay of information. Mesh networks dynamically self-organize and self-configure, which can reduce installation overhead. The ability to self-configure enables dynamic distribution of workloads, particularly in the event a few nodes should fail. This in turn contributes to fault-tolerance and reduced maintenance costs.
Mesh topology may be contrasted with conventional star/tree local network topologies in which the bridges/switches are directly linked to only a small subset of other bridges/switches, and the links between these infrastructure neighbours are hierarchical. While star-and-tree topologies are very well established, highly standardized and vendor-neutral, vendors of mesh network devices have not yet all agreed on common standards, and interoperability between devices from different vendors is not yet assured.
== Basic principles ==
Mesh networks can relay messages using either a flooding or a routing technique, which makes them different from non-mesh networks. A routed message is propagated along a path by hopping from node to node until it reaches its destination. To ensure that all its paths are available, the network must allow for continuous connections and must reconfigure itself around broken paths, using self-healing algorithms such as Shortest Path Bridging and TRILL (Transparent Interconnection of Lots of Links). Self-healing allows a routing-based network to operate when a node breaks down or when a connection becomes unreliable. The network is typically quite reliable, as there is often more than one path between a source and a destination in the network. Although mostly used in wireless situations, this concept can also apply to wired networks and to software interaction.
A mesh network whose nodes are all connected to each other is a fully connected network. Fully connected wired networks are more secure and reliable: problems in a cable affect only the two nodes attached to it. In such networks, however, the number of cables, and therefore the cost, goes up rapidly as the number of nodes increases.
== Types ==
=== Wired mesh ===
Shortest path bridging and TRILL each allow Ethernet switches to be connected in a mesh topology and allow for all paths to be active. IP routing supports multiple paths from source to destination.
=== Wireless mesh ===
A wireless mesh network (WMN) is a network made up of radio nodes organized in a mesh topology. It can also be a form of wireless ad hoc network.
== See also ==
Category of mesh networking technologies
Bluetooth mesh networking
MENTOR routing algorithm
Optical mesh network
== References ==
== External links ==
NYU-NET3 at the Wayback Machine (archived 2015-07-08) Application of a tetrahedral structure to create a resilient partial-mesh 3-dimensional campus backbone data network
Phantom anonymous, decentralized network, isolated from the Internet
Disruption Tolerant Mesh Networks autonomous machine controller in mesh nodes operate despite loss of cloud connectivity. | Wikipedia/Mesh_networking |
Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel in a communication network, such as Ethernet or packet radio. The data that these messages contain may be delivered over physical or logical links, or through network nodes. Throughput is usually measured in bits per second (bit/s, sometimes abbreviated bps), and sometimes in packets per second (p/s or pps) or data packets per time slot.
The system throughput or aggregate throughput is the sum of the data rates that are delivered over all channels in a network. Throughput represents digital bandwidth consumption.
The throughput of a communication system may be affected by various factors, including the limitations of the underlying physical medium, available processing power of the system components, end-user behavior, etc. When taking various protocol overheads into account, the useful rate of the data transfer can be significantly lower than the maximum achievable throughput; the useful part is usually referred to as goodput.
== Maximum throughput ==
Users of telecommunications devices, systems designers, and researchers into communication theory are often interested in knowing the expected performance of a system. From a user perspective, this is often phrased as either "which device will get my data there most effectively for my needs?", or "which device will deliver the most data per unit cost?". Systems designers often select the most effective architecture or design constraints for a system, which drive its final performance. In most cases, the benchmark of what a system is capable of, or its maximum performance is what the user or designer is interested in. The term maximum throughput is frequently used when discussing end-user maximum throughput tests. Maximum throughput is essentially synonymous with digital bandwidth capacity.
Four different values are relevant in the context of maximum throughput are used in comparing the upper limit conceptual performance of multiple systems. They are maximum theoretical throughput, maximum achievable throughput, peak measured throughput, and maximum sustained throughput. These values represent different qualities, and care must be taken that the same definitions are used when comparing different maximum throughput values.
Each bit must carry the same amount of information if throughput values are to be compared. Data compression can significantly alter throughput calculations, including generating values exceeding 100% in some cases.
If the communication is mediated by several links in series with different bit rates, the maximum throughput of the overall link is lower than or equal to the lowest bit rate. The lowest value link in the series is referred to as the bottleneck.
=== Maximum theoretical throughput ===
Maximum theoretical throughput is closely related to the channel capacity of the system, and is the maximum possible quantity of data that can be transmitted under ideal circumstances. In some cases, this number is reported as equal to the channel capacity, though this can be deceptive, as only non-packetized systems technologies can achieve this. Maximum theoretical throughput is more accurately reported taking into account format and specification overhead with best-case assumptions.
=== Asymptotic throughput ===
The asymptotic throughput (less formal asymptotic bandwidth) for a packet-mode communication network is the value of the maximum throughput function, when the incoming network load approaches infinity, either due to a message size, or the number of data sources. As with other bit rates and data bandwidths, the asymptotic throughput is measured in bits per second (bit/s) or (rarely) bytes per second (B/s), where 1 B/s is 8 bit/s. Decimal prefixes are used, meaning that 1 Mbit/s is 1000000 bit/s.
Asymptotic throughput is usually estimated by sending or simulating a very large message (sequence of data packets) through the network, using a greedy source and no flow control mechanism (i.e., UDP rather than TCP), and measuring the volume of data received at the destination node. Traffic load between other sources may reduce this maximum network path throughput. Alternatively, a large number of sources and sinks may be modeled, with or without flow control, and the aggregate maximum network throughput measured (the sum of traffic reaching its destinations). In a network simulation model with infinitately large packet queues, the asymptotic throughput occurs when the latency (the packet queuing time) goes to infinity, while if the packet queues are limited, or the network is a multi-drop network with many sources, and collisions may occur, the packet-dropping rate approaches 100%.
A well-known application of asymptotic throughput is in modeling point-to-point communication where message latency
T
(
N
)
{\displaystyle T(N)}
is modeled as a function of message length
N
{\displaystyle N}
as
T
(
N
)
=
(
M
+
N
)
/
A
{\displaystyle T(N)=(M+N)/A}
where
A
{\displaystyle A}
is the asymptotic bandwidth and
M
{\displaystyle M}
is the half-peak length.
As well as its use in general network modeling, asymptotic throughput is used in modeling performance on massively parallel computer systems, where system operation is highly dependent on communication overhead, as well as processor performance. In these applications, asymptotic throughput is used modeling which includes the number of processors, so that both the latency and the asymptotic throughput are functions of the number of processors.
=== Peak measured throughput ===
Where asymptotic throughput is a theoretical or calculated capacity, peak measured throughput is throughput measured on a real implemented system, or on a simulated system. The value is the throughput measured over a short period of time; mathematically, this is the limit taken with respect to throughput as time approaches zero. This term is synonymous with instantaneous throughput. This number is useful for systems that rely on burst data transmission; however, for systems with a high duty cycle, this is less likely to be a useful measure of system performance.
=== Maximum sustained throughput ===
This value is the throughput averaged or integrated over a long time (sometimes considered infinity). For high duty cycle networks, this is likely to be the most accurate indicator of system performance. The maximum throughput is defined as the asymptotic throughput when the load (the amount of incoming data) is large. In packet switched systems where the load and the throughput always are equal (where packet loss does not occur), the maximum throughput may be defined as the minimum load in bit/s that causes the delivery time (the latency) to become unstable and increase towards infinity. This value can also be used deceptively in relation to peak measured throughput to conceal packet shaping.
== Channel utilization and efficiency ==
Throughput is sometimes normalized and measured in percentage, but normalization may cause confusion regarding what the percentage is related to. Channel utilization, channel efficiency and packet drop rate in percentage are less ambiguous terms.
The channel efficiency, also known as bandwidth utilization efficiency, is the percentage of the net bit rate (in bit/s) of a digital communication channel that goes to the actually achieved throughput. For example, if the throughput is 70 Mbit/s in a 100 Mbit/s Ethernet connection, the channel efficiency is 70%. In this example, effectively 70 Mbit of data are transmitted every second.
Channel utilization is instead a term related to the use of the channel, disregarding the throughput. It counts not only with the data bits, but also with the overhead that makes use of the channel. The transmission overhead consists of preamble sequences, frame headers and acknowledge packets. The definitions assume a noiseless channel. Otherwise, the throughput would not be only associated with the nature (efficiency) of the protocol, but also to retransmissions resultant from the quality of the channel. In a simplistic approach, channel efficiency can be equal to channel utilization assuming that acknowledge packets are zero-length and that the communications provider will not see any bandwidth relative to retransmissions or headers. Therefore, certain texts mark a difference between channel utilization and protocol efficiency.
In a point-to-point or point-to-multipoint communication link, where only one terminal is transmitting, the maximum throughput is often equivalent to or very near the physical data rate (the channel capacity), since the channel utilization can be almost 100% in such a network, except for a small inter-frame gap.
For example, the maximum frame size in Ethernet is 1526 bytes: up to 1500 bytes for the payload, eight bytes for the preamble, 14 bytes for the header, and 4 bytes for the trailer. An additional minimum interframe gap corresponding to 12 bytes is inserted after each frame. This corresponds to a maximum channel utilization of 1526 / (1526 + 12) × 100% = 99.22%, or a maximum channel use of 99.22 Mbit/s inclusive of Ethernet datalink layer protocol overhead in a 100 Mbit/s Ethernet connection. The maximum throughput or channel efficiency is then 1500 / (1526 + 12) = 97.5%, exclusive of the Ethernet protocol overhead.
== Factors affecting throughput ==
The throughput of a communication system will be limited by a huge number of factors. Some of these are described below:
=== Analog limitations ===
The maximum achievable throughput (the channel capacity) is affected by the bandwidth in hertz and signal-to-noise ratio of the analog physical medium.
Despite the conceptual simplicity of digital information, all electrical signals traveling over wires are analog. The analog limitations of wires or wireless systems inevitably provide an upper bound on the amount of information that can be sent. The dominant equation here is the Shannon–Hartley theorem, and analog limitations of this type can be understood as factors that affect either the analog bandwidth of a signal or as factors that affect the signal-to-noise ratio. The bandwidth of wired systems can be in fact surprisingly narrow, with the bandwidth of Ethernet wire limited to approximately 1 GHz, and PCB traces limited by a similar amount.
Digital systems refer to the 'knee frequency', the amount of time for the digital voltage to rise from 10% of a nominal digital '0' to a nominal digital '1' or vice versa. The knee frequency is related to the required bandwidth of a channel, and can be related to the 3 db bandwidth of a system by the equation:
F
3
d
B
≈
K
/
T
r
{\displaystyle \ F_{3dB}\approx K/T_{r}}
Where Tr is the 10% to 90% rise time, and K is a constant of proportionality related to the pulse shape, equal to 0.35 for an exponential rise, and 0.338 for a Gaussian rise.
RC losses: Wires have an inherent resistance, and an inherent capacitance when measured with respect to ground. This leads to effects called parasitic capacitance, causing all wires and cables to act as RC lowpass filters.
Skin effect: As frequency increases, electric charges migrate to the edges of wires or cable. This reduces the effective cross-sectional area available for carrying current, increasing resistance and reducing the signal-to-noise ratio. For AWG 24 wire (of the type commonly found in Cat 5e cable), the skin effect frequency becomes dominant over the inherent resistivity of the wire at 100 kHz. At 1 GHz the resistivity has increased to 0.1 ohm per inch.
Termination and ringing: Wires longer than about 1/6 wavelengths must be modeled as transmission lines with termination taken into account. Unless this is done, reflected signals will travel back and forth across the wire, positively or negatively interfering with the information-carrying signal.
Wireless Channel Effects: For wireless systems, all of the effects associated with wireless transmission limit the SNR and bandwidth of the received signal, and therefore the maximum bit transmission rate.
=== IC hardware considerations ===
Computational systems have finite processing power and can drive finite current. Limited current drive capability can limit the effective signal to noise ratio for high capacitance links.
Large data loads that require processing impose data processing requirements on hardware (such as routers). For example, a gateway router supporting a populated class B subnet, handling 10 × 100 Mbit/s Ethernet channels, must examine 16 bits of address to determine the destination port for each packet. This translates into 81913 packets per second (assuming maximum data payload per packet) with a table of 2^16 addresses this requires the router to be able to perform 5.368 billion lookup operations per second. In a worst-case scenario, where the payloads of each Ethernet packet are reduced to 100 bytes, this number of operations per second jumps to 520 billion. This router would require a multi-teraflop processing core to be able to handle such a load.
CSMA/CD and CSMA/CA "backoff" waiting time and frame retransmissions after detected collisions. This may occur in Ethernet bus networks and hub networks, as well as in wireless networks.
Flow control, for example in the Transmission Control Protocol (TCP) protocol, affects the throughput if the bandwidth-delay product is larger than the TCP window, i.e., the buffer size. In that case, the sending computer must wait for acknowledgement of the data packets before it can send more packets.
TCP congestion avoidance controls the data rate. A so-called "slow start" occurs in the beginning of a file transfer, and after packet drops caused by router congestion or bit errors in for example wireless links.
=== Multi-user considerations ===
Ensuring that multiple users can harmoniously share a single communications link requires some kind of equitable sharing of the link. If a bottleneck communication link offering data rate R is shared by "N" active users (with at least one data packet in queue), every user typically achieves a throughput of approximately R/N, if fair queuing best-effort communication is assumed.
Packet loss due to network congestion. Packets may be dropped in switches and routers when the packet queues are full due to congestion.
Packet loss due to bit errors.
Scheduling algorithms in routers and switches. If fair queuing is not provided, users that send large packets will get higher bandwidth. Some users may be prioritized in a weighted fair queuing (WFQ) algorithm if differentiated or guaranteed quality of service (QoS) is provided.
In some communications systems, such as satellite networks, only a finite number of channels may be available to a given user at a given time. Channels are assigned either through preassignment or through Demand Assigned Multiple Access (DAMA). In these cases, throughput is quantized per channel, and unused capacity on partially utilized channels is lost.
== Goodput and overhead ==
The maximum throughput is often an unreliable measurement of perceived bandwidth, for example the file transmission data rate in bits per seconds. As pointed out above, the achieved throughput is often lower than the maximum throughput. Also, the protocol overhead affects the perceived bandwidth. The throughput is not a well-defined metric when it comes to how to deal with protocol overhead. It is typically measured at a reference point below the network layer and above the physical layer. The simplest definition is the number of bits per second that are physically delivered. A typical example where this definition is practiced is an Ethernet network. In this case, the maximum throughput is the gross bit rate or raw bit rate.
However, in schemes that include forward error correction codes (channel coding), the redundant error code is normally excluded from the throughput. An example in modem communication, where the throughput typically is measured in the interface between the Point-to-Point Protocol (PPP) and the circuit-switched modem connection. In this case, the maximum throughput is often called net bit rate or useful bit rate.
To determine the actual data rate of a network or connection, the "goodput" measurement definition may be used. For example, in file transmission, the "goodput" corresponds to the file size (in bits) divided by the file transmission time. The "goodput" is the amount of useful information that is delivered per second to the application layer protocol. Dropped packets or packet retransmissions, as well as protocol overhead, are excluded. Because of that, the "goodput" is lower than the throughput. Technical factors that affect the difference are presented in the "goodput" article.
== Other uses of throughput for data ==
=== Integrated circuits ===
Often, a block in a data flow diagram has a single input and a single output, and operate on discrete packets of information. Examples of such blocks are fast Fourier transform modules or binary multipliers. Because the units of throughput are the reciprocal of the unit for propagation delay, which is 'seconds per message' or 'seconds per output', throughput can be used to relate a computational device performing a dedicated function such as an ASIC or embedded processor to a communications channel, simplifying system analysis.
=== Wireless and cellular networks ===
In wireless networks or cellular systems, the system spectral efficiency in bit/s/Hz/area unit, bit/s/Hz/site or bit/s/Hz/cell, is the maximum system throughput (aggregate throughput) divided by the analog bandwidth and some measure of the system coverage area.
=== Over analog channels ===
Throughput over analog channels is defined entirely by the modulation scheme, the signal-to-noise ratio, and the available bandwidth. Since throughput is normally defined in terms of quantified digital data, the term 'throughput' is not normally used; the term 'bandwidth' is more often used instead.
== See also ==
== References ==
== Further reading ==
Rappaport, Theodore S. Wireless Communications, Principles and Practice second edition, Prentice Hall, 2002, ISBN 0-13-042232-0
Blahut, Richard E. Algebraic Codes for Data Transmission Cambridge University Press, 2004, ISBN 0-521-55374-1
Li, Harnes, Holte, "Impact of Lossy Links on Performance of Multihop Wireless Networks", IEEE, Proceedings of the 14th International Conference on Computer Communications and Networks, Oct 2005, 303 - 308
Johnson, Graham, High Speed Digital Design, a Handbook of Black Magic, Prentice Hall, 1973, ISBN 0-13-395724-1
Roddy, Dennis, Satellite Communications third edition, McGraw-Hill, 2001, ISBN 0-07-137176-1 | Wikipedia/Network_throughput |
In computing, network virtualization is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization.
Network virtualization is categorized as either external virtualization, combining many networks or parts of networks into a virtual unit, or internal virtualization, providing network-like functionality to software containers on a single network server.
In software testing, software developers use network virtualization to test software which are under development in a simulation of the network environments in which the software is intended to operate. As a component of application performance engineering, network virtualization enables developers to emulate connections between applications, services, dependencies, and end users in a test environment without having to physically test the software on all possible hardware or system software. The validity of the test depends on the accuracy of the network virtualization in emulating real hardware and operating systems.
== Components ==
Various equipment and software vendors offer network virtualization by combining any of the following:
Network hardware, such as switches and network adapters, also known as network interface cards (NICs)
Network elements, such as firewalls and load balancers
Networks, such as virtual LANs (VLANs) and containers such as virtual machines (VMs)
Network storage devices
Network machine-to-machine elements, such as telecommunications devices
Network mobile elements, such as laptop computers, tablet computers, and smartphones
Network media, such as Ethernet and Fibre Channel
== External virtualization ==
External network virtualization combines or subdivides one or more local area networks (LANs) into virtual networks to improve a large network's or data center's efficiency. A virtual local area network (VLAN) and network switch comprise the key components. Using this technology, a system administrator can configure systems physically attached to the same local network into separate virtual networks. Conversely, an administrator can combine systems on separate local area networks (LANs) into a single VLAN spanning segments of a large network.
External network virtualization is envisioned to be placed in the middle of the network stack and help integrating different architectures proposed for next generation networks.
== Internal virtualization ==
Internal network virtualization configures a single system with software containers, such as Xen hypervisor control programs, or pseudo-interfaces, such as a VNIC, to emulate a physical network with software. This can improve a single system's efficiency by isolating applications to separate containers or pseudo-interfaces.
=== Examples ===
Citrix and Vyatta have built a virtual network protocol stack combining Vyatta's routing, firewall, and VPN functions with Citrix's Netscaler load balancer, branch repeater wide area network (WAN) optimization, and secure sockets layer VPN.
OpenSolaris network virtualization provides a so-called "network in a box" (see OpenSolaris Network Virtualization and Resource Control).
Microsoft Virtual Server uses virtual machines to make a "network in a box" for x86 systems. These containers can run different operating systems, such as Microsoft Windows or Linux, either associated with or independent of a specific network interface controller (NIC).
== Use in testing ==
Network virtualization may be used in application development and testing to mimic real-world hardware and system software.
In application performance engineering, network virtualization enables emulation of connections between applications, services, dependencies, and end users for software testing.
== Wireless network virtualization ==
Wireless network virtualization can have a very broad scope ranging from spectrum sharing, infrastructure virtualization, to air interface virtualization. Similar to wired network virtualization, in which physical infrastructure owned by one or more providers can be shared among multiple service providers, wireless network virtualization needs the physical wireless infrastructure and radio resources to be abstracted and isolated to a number of virtual resources, which then can be offered to different service providers. In other words, virtualization, regardless of wired or wireless networks, can be considered as a process splitting the entire network system. However, the distinctive properties of the wireless environment, in terms of time-various channels, attenuation, mobility, broadcast, etc., make the problem more complicated. Furthermore, wireless network virtualization depends on specific access technologies, and wireless network contains much more access technologies compared to wired network virtualization and each access technology has its particular characteristics, which makes convergence, sharing and abstraction difficult to achieve. Therefore, it may be inaccurate to consider wireless network virtualization as a subset of network virtualization.
== Performance ==
Until 1 Gbit/s networks, network virtualization was not suffering from the overhead of the software layers or hypervisor layers providing the interconnects. With the rise of high bandwidth, 10 Gbit/s and beyond, the rates of packets exceed the capabilities of processing of the networking stacks. In order to keep offering high throughput processing, some combinations of software and hardware helpers are deployed in the so-called "network in a box" associated with either a hardware-dependent network interface controller (NIC) using SRIOV extensions of the hypervisor or either using a fast path technology between the NIC and the payloads (virtual machines or containers).
For example, in case of Openstack, network is provided by Neutron which leverages many features from the Linux kernel for networking: iptables, iproute2, L2 bridge, L3 routing or OVS. Since the Linux kernel cannot sustain the 10G packet rate, then some bypass technologies for a fast path are used. The main bypass technologies are either based on a limited set of features such as Open vSwitch (OVS) with its DPDK user space implementation or based on a full feature and offload of Linux processing such as 6WIND virtual accelerator.
== See also ==
== References ==
== Further reading ==
Esposito, Flavio; Matta, Ibrahim; Ishakian, Vatche (2011). "Slice Embedding Solutions for Distributed Service Architectures" (PDF). ACM Computing Surveys. 46 (1): 1–29. CiteSeerX 10.1.1.300.4425. doi:10.1145/2522968.2522974. hdl:2144/11382. S2CID 2307120. Retrieved 5 December 2017.
Chowdhury, N.M. Mosharaf Kabir; Boutaba, Raouf (2010). "A survey of network virtualization". Computer Networks. 54 (5): 862–876. doi:10.1016/j.comnet.2009.10.017. ISSN 1389-1286.
Berl, Andreas; Fischer, Andreas; de Meer, Hermann (2009). "Using System Virtualization to Create Virtualized Networks". Electronic Communications of the EASST. 17: 1–12. ISSN 1863-2122.
Fischer, Andreas; Botero, Juan Felipe; Beck, Michael Till; de Meer, Hermann; Hesselbach, Xavier (2013). "Virtual Network Embedding: A Survey". IEEE Communications Surveys & Tutorials. 15 (4): 1–19. doi:10.1109/SURV.2013.013013.00155. hdl:2117/20996. ISSN 1553-877X. S2CID 206584013.
== External links ==
NetworkVirtualization.com | News retrieved 3 June 2008
RAD VPLS Tutorial
Types of VPNs
VMware Virtual Networking Concepts retrieved 26 October 2008
Network functions Virtualization(NFV) Benefits | Wikipedia/Network_virtualization |
Intent-Based Networking (IBN) is an approach to network management that shifts the focus from manually configuring individual devices to specifying desired outcomes or business objectives, referred to as "intents".
== Description ==
Rather than relying on low-level commands to configure the network, administrators define these high-level intents, and the network dynamically adjusts itself to meet these requirements. IBN simplifies the management of complex networks by ensuring that the network infrastructure aligns with the desired operational goals. For example, an implementer can explicitly state a network purpose with a policy such as "Allow hosts A and B to communicate with X bandwidth capacity" without the need to understand the detailed mechanisms of the underlying devices (e.g. switches), topology or routing configurations.
== Architecture ==
Advances in Natural Language Understanding (NLU) systems, along with neural network-based algorithms like BERT, RoBERTa, GLUE, and ERNIE, have enabled the conversion of user queries into structured representations that can be processed by automated services. This capability is crucial for managing the increasing complexity of network services. Intent-Based Networking (IBN) leverages these advancements to simplify network management by abstracting network services, reducing operational complexity, and lowering costs.
A proposed three-layered architecture integrates intent-based automation into network management systems. In the business layer, intents are based on Key Performance Indicators (KPIs) and Service Level Agreements (SLAs), reflecting business objectives. The intent layer evaluates and re-plans actions dynamically, where a Knowledge module abstracts and reasons about intents, while an Agent interfaces with network objects to execute actions. The data layer observes network objects, updates topology information, and interacts with the Knowledge and Agent modules to ensure accurate and timely responses to network changes. At the bottom, the network layer contains the physical infrastructure, transforming network data into a usable format for the intent layer to act upon.
== References == | Wikipedia/Intent-based_network |
The function point is a "unit of measurement" to express the amount of business functionality an information system (as a product) provides to a user. Function points are used to compute a functional size measurement (FSM) of software. The cost (in dollars or hours) of a single unit is calculated from past projects.
== Standards ==
There are several recognized standards and/or public specifications for sizing software based on Function Point.
1. ISO Standards
FiSMA: ISO/IEC 29881:2010 Information technology – Systems and software engineering – FiSMA 1.1 functional size measurement method.
IFPUG: ISO/IEC 20926:2009 Software and systems engineering – Software measurement – IFPUG functional size measurement method.
Mark-II: ISO/IEC 20968:2002 Software engineering – Ml II Function Point Analysis – Counting Practices Manual
Nesma: ISO/IEC 24570:2018 Software engineering – Nesma functional size measurement method version 2.3 – Definitions and counting guidelines for the application of Function Point Analysis
COSMIC: ISO/IEC 19761:2011 Software engineering. A functional size measurement method.
OMG: ISO/IEC 19515:2019 Information technology — Object Management Group Automated Function Points (AFP), 1.0
The first five standards are implementations of the over-arching standard for Functional Size Measurement ISO/IEC 14143. The OMG Automated Function Point (AFP) specification, led by the Consortium for IT Software Quality, provides a standard for automating the Function Point counting according to the guidelines of the International Function Point User Group (IFPUG) However, the current implementations of this standard have a limitation in being able to distinguish External Output (EO) from External Inquiries (EQ) out of the box, without some upfront configuration.
== Introduction ==
Function points were defined in 1979 in Measuring Application Development Productivity by Allan J. Albrecht at IBM. The functional user requirements of the software are identified and each one is categorized into one of five types: outputs, inquiries, inputs, internal files, and external interfaces. Once the function is identified and categorized into a type, it is then assessed for complexity and assigned a number of function points. Each of these functional user requirements maps to an end-user business function, such as a data entry for an Input or a user query for an Inquiry. This distinction is important because it tends to make the functions measured in function points map easily into user-oriented requirements, but it also tends to hide internal functions (e.g. algorithms), which also require resources to implement.
There is currently no ISO recognized FSM Method that includes algorithmic complexity in the sizing result. Recently there have been different approaches proposed to deal with this perceived weakness, implemented in several commercial software products. The variations of the Albrecht-based IFPUG method designed to make up for this (and other weaknesses) include:
Early and easy function points – Adjusts for problem and data complexity with two questions that yield a somewhat subjective complexity measurement; simplifies measurement by eliminating the need to count data elements.
Engineering function points – Elements (variable names) and operators (e.g., arithmetic, equality/inequality, Boolean) are counted. This variation highlights computational function. The intent is similar to that of the operator/operand-based Halstead complexity measures.
Bang measure – Defines a function metric based on twelve primitive (simple) counts that affect or show Bang, defined as "the measure of true function to be delivered as perceived by the user." Bang measure may be helpful in evaluating a software unit's value in terms of how much useful function it provides, although there is little evidence in the literature of such application. The use of Bang measure could apply when re-engineering (either complete or piecewise) is being considered, as discussed in Maintenance of Operational Systems—An Overview.
Feature points – Adds changes to improve applicability to systems with significant internal processing (e.g., operating systems, communications systems). This allows accounting for functions not readily perceivable by the user, but essential for proper operation.
Weighted Micro Function Points – One of the newer models (2009) which adjusts function points using weights derived from program flow complexity, operand and operator vocabulary, object usage, and algorithm.
Fuzzy Function Points - Proposes a fuzzy and gradative transition between low x medium and medium x high complexities
== Contrast ==
The use of function points in favor of lines of code seek to address several additional issues:
The risk of "inflation" of the created lines of code, and thus reducing the value of the measurement system, if developers are incentivized to be more productive. FP advocates refer to this as measuring the size of the solution instead of the size of the problem.
Lines of Code (LOC) measures reward low level languages because more lines of code are needed to deliver a similar amount of functionality to a higher level language. C. Jones offers a method of correcting this in his work.
LOC measures are not useful during early project phases where estimating the number of lines of code that will be delivered is challenging. However, Function Points can be derived from requirements and therefore are useful in methods such as estimation by proxy.
== Criticism ==
Albrecht observed in his research that Function Points were highly correlated to lines of code, which has resulted in a questioning of the value of such a measure if a more objective measure, namely counting lines of code, is available. In addition, there have been multiple attempts to address perceived shortcomings with the measure by augmenting the counting regimen. Others have offered solutions to circumvent the challenges by developing alternative methods which create a proxy for the amount of functionality delivered.
== See also ==
COCOMO (Constructive Cost Model)
Comparison of development estimation software
COSMIC functional size measurement
Mark II method
Object point
Software development effort estimation
Software Sizing
Source lines of code
Use Case Points
The Simple Function Point method
== References ==
== External links ==
The International Function Point Users Group (IFPUG) | Wikipedia/Function_point |
Industrial design is a process of design applied to physical products that are to be manufactured by mass production. It is the creative act of determining and defining a product's form and features, which takes place in advance of the manufacture or production of the product. Industrial manufacture consists of predetermined, standardized and repeated, often automated, acts of replication, while craft-based design is a process or approach in which the form of the product is determined personally by the product's creator largely concurrent with the act of its production.
All manufactured products are the result of a design process, but the nature of this process can vary. It can be conducted by an individual or a team, and such a team could include people with varied expertise (e.g. designers, engineers, business experts, etc.). It can emphasize intuitive creativity or calculated scientific decision-making, and often emphasizes a mix of both. It can be influenced by factors as varied as materials, production processes, business strategy, and prevailing social, commercial, or aesthetic attitudes. Industrial design, as an applied art, most often focuses on a combination of aesthetics and user-focused considerations, but also often provides solutions for problems of form, function, physical ergonomics, marketing, brand development, sustainability, and sales.
== History ==
=== Precursors ===
For several millennia before the onset of industrialization, design, technical expertise, and manufacturing was often done by individual crafts people, who determined the form of a product at the point of its creation, according to their own manual skill, the requirements of their clients, experience accumulated through their own experimentation, and knowledge passed on to them through training or apprenticeship.
The division of labour that underlies the practice of industrial design did have precedents in the pre-industrial era. The growth of trade in the medieval period led to the emergence of large workshops in cities such as Florence, Venice, Nuremberg, and Bruges, where groups of more specialized craftsmen made objects with common forms through the repetitive duplication of models which defined by their shared training and technique. Competitive pressures in the early 16th century led to the emergence in Italy and Germany of pattern books: collections of engravings illustrating decorative forms and motifs which could be applied to a wide range of products, and whose creation took place in advance of their application. The use of drawing to specify how something was to be constructed later was first developed by architects and shipwrights during the Italian Renaissance.
In the 17th century, the growth of artistic patronage in centralized monarchical states such as France led to large government-operated manufacturing operations epitomized by the Gobelins Manufactory, opened in Paris in 1667 by Louis XIV. Here teams of hundreds of craftsmen, including specialist artists, decorators and engravers, produced sumptuously decorated products ranging from tapestries and furniture to metalwork and coaches, all under the creative supervision of the King's leading artist Charles Le Brun. This pattern of large-scale royal patronage was repeated in the court porcelain factories of the early 18th century, such as the Meissen porcelain workshops established in 1709 by the Grand Duke of Saxony, where patterns from a range of sources, including court goldsmiths, sculptors, and engravers, were used as models for the vessels and figurines for which it became famous. As long as reproduction remained craft-based, however, the form and artistic quality of the product remained in the hands of the individual craftsman, and tended to decline as the scale of production increased.
=== Birth of industrial design ===
The emergence of industrial design is specifically linked to the growth of industrialization and mechanization that began with the Industrial Revolution in Great Britain in the mid 18th century. The rise of industrial manufacture changed the way objects were made, urbanization changed patterns of consumption, the growth of empires broadened tastes and diversified markets, and the emergence of a wider middle class created demand for fashionable styles from a much larger and more heterogeneous population.
The first use of the term "industrial design" is often attributed to the industrial designer Joseph Claude Sinel in 1919 (although he himself denied this in interviews), but the discipline predates 1919 by at least a decade. Christopher Dresser is considered among the first independent industrial designers. Industrial design's origins lie in the industrialization of consumer products. For instance, the Deutscher Werkbund (a precursor to the Bauhaus founded in 1907 by Peter Behrens and others) was a state-sponsored effort to integrate traditional crafts and industrial mass-production techniques, to put Germany on a competitive footing with Great Britain and the United States.
The earliest published use of the term may have been in The Art-Union, 15 September 1840.
Dyce's Report to the Board of Trade, on Foreign Schools of Design for Manufactures.
Mr. Dyce's official visit to France, Prussia, and Bavaria, for the purpose of examining the state of schools of design in those countries, will be fresh in the recollection of our readers. His report on this subject was ordered to be printed some few months since, on the motion of Mr. Hume; and it is the sum and substance of this Report that we are now about to lay before our own especial portion of the reading public.
The school of St. Peter, at Lyons, was founded about 1750, for the instruction of draftsmen employed in preparing patterns for the silk manufacture. It has been much more successful than the Paris school; and having been disorganized by the revolution, was restored by Napoleon and differently constituted, being then erected into an Academy of Fine Art: to which the study of design for silk manufacture was merely attached as a subordinate branch.
It appears that all the students who entered the school commence as if they were intended for artists in the higher sense of the word and are not expected to decide as to whether they will devote themselves to the Fine Arts or to Industrial Design, until they have completed their exercises in drawing and painting of the figure from the antique and from the living model. It is for this reason, and from the fact that artists for industrial purposes are both well-paid and highly considered (as being well-instructed men), that so many individuals in France engage themselves in both pursuits.
The Practical Draughtsman's Book of Industrial Design by Jacques-Eugène Armengaud was printed in 1853. The subtitle of the (translated) work explains, that it wants to offer a "complete course of mechanical, engineering, and architectural drawing." The study of those types of technical drawing, according to Armengaud, belongs to the field of industrial design. This work paved the way for a big expansion in the field of drawing education in France, the United Kingdom, and the United States.
Robert Lepper helped to establish one of the USA's first industrial design degree programs in 1934 at Carnegie Institute of Technology.
== Education ==
Product design and industrial design overlap in the fields of user interface design, information design, and interaction design. Various schools of industrial design specialize in one of these aspects, ranging from pure art colleges and design schools (product styling), to mixed programs of engineering and design, to related disciplines such as exhibit design and interior design, to schools that almost completely subordinated aesthetic design to concerns of usage and ergonomics, the so-called functionalist school. Except for certain functional areas of overlap between industrial design and engineering design, the former is considered an applied art while the latter is an applied science. Educational programs in the U.S. for engineering require accreditation by the Accreditation Board for Engineering and Technology (ABET) in contrast to programs for industrial design which are accredited by the National Association of Schools of Art and Design (NASAD). Of course, engineering education requires heavy training in mathematics and physical sciences, which is not typically required in industrial design education.
=== Institutions ===
Most industrial designers complete a design or related program at a vocational school or university. Relevant programs include graphic design, interior design, industrial design, architectural technology, and drafting. Diplomas and degrees in industrial design are offered at vocational schools and universities worldwide. Diplomas and degrees take two to four years of study. The study results in a Bachelor of Industrial Design (B.I.D.), Bachelor of Science (B.Sc.) or Bachelor of Fine Arts (B.F.A.). Afterwards, the bachelor programme can be extended to postgraduate degrees such as Master of Design, Master of Fine Arts and others to a Master of Arts or Master of Science.
== Definition ==
Industrial design studies function and form—and the connection between product, user, and environment. Generally, industrial design professionals work in small scale design, rather than overall design of complex systems such as buildings or ships. Industrial designers don't usually design motors, electrical circuits, or gearing that make machines move, but they may affect technical aspects through usability design and form relationships. Usually, they work with other professionals such as engineers who focus on the mechanical and other functional aspects of the product, assuring functionality and manufacturability, and with marketers to identify and fulfill customer needs and expectations.
Design, itself, is often difficult to describe to non-designers because the meaning accepted by the design community is not made of words. Instead, the definition is created as a result of acquiring a critical framework for the analysis and creation of artifacts. One of the many accepted (but intentionally unspecific) definitions of design originates from Carnegie Mellon's School of Design: "Everyone designs who devises courses of action aimed at changing existing situations into preferred ones." This applies to new artifacts, whose existing state is undefined, and previously created artifacts, whose state stands to be improved.
Industrial design can overlap significantly with engineering design, and in different countries the boundaries of the two concepts can vary, but in general engineering focuses principally on functionality or utility of products, whereas industrial design focuses principally on aesthetic and user-interface aspects of products. In many jurisdictions this distinction is effectively defined by credentials and/or licensure required to engage in the practice of engineering. "Industrial design" as such does not overlap much with the engineering sub-discipline of industrial engineering, except for the latter's sub-specialty of ergonomics.
At the 29th General Assembly in Gwangju, South Korea, 2015, the Professional Practise Committee unveiled a renewed definition of industrial design as follows:
"Industrial Design is a strategic problem-solving process that drives innovation, builds business success and leads to a better quality of life through innovative products, systems, services and experiences."
An extended version of this definition is as follows:
"Industrial Design is a strategic problem-solving process that drives innovation, builds business success and leads to a better quality of life through innovative products, systems, services and experiences. Industrial Design bridges the gap between what is and what's possible. It is a trans-disciplinary profession that harnesses creativity to resolve problems and co-create solutions with the intent of making a product, system, service, experience or a business, better. At its heart, Industrial Design provides a more optimistic way of looking at the future by reframing problems as opportunities. It links innovation, technology, research, business and customers to provide new value and competitive advantage across economic, social and environmental spheres.
Industrial Designers place the human in the centre of the process. They acquire a deep understanding of user needs through empathy and apply a pragmatic, user centric problem solving process to design products, systems, services and experiences. They are strategic stakeholders in the innovation process and are uniquely positioned to bridge varied professional disciplines and business interests. They value the economic, social and environmental impact of their work and their contribution towards co-creating a better quality of life. "
== Design process ==
Although the process of design may be considered 'creative,' many analytical processes also take place. In fact, many industrial designers often use various design methodologies in their creative process. Some of the processes that are commonly used are user research, sketching, comparative product research, model making, prototyping and testing. The design process is iterative, involving dozens or even hundreds of ideas being considered until the final design is reached. Industrial designers often utilize 3D software, computer-aided industrial design and CAD programs to move from concept to production. They may also build a prototype or scaled down sketch models through a 3D printing process or using other materials such as paper, balsa wood, various foams, or clay for modeling. They may then use industrial CT scanning to test for interior defects and generate a CAD model. From this the manufacturing process may be modified to improve the product.
Product characteristics specified by industrial designers may include the overall form of the object, the location of details with respect to one another, colors, texture, form, and aspects concerning the use of the product. Additionally, they may specify aspects concerning the production process, choice of materials and the way the product is presented to the consumer at the point of sale. The inclusion of industrial designers in a product development process may lead to added value by improving usability, lowering production costs, and developing more appealing products.
Industrial design may also focus on technical concepts, products, and processes. In addition to aesthetics, human factors, ergonomics and anthropometrics, it can also encompass engineering, usefulness, market placement, and other concerns—such as psychology, and the emotional attachment of the user. These values and accompanying aspects that form the basis of industrial design can vary—between different schools of thought, and among practicing designers.
== Industrial design rights ==
Industrial design rights are intellectual property rights that make exclusive the visual design of objects that are not purely utilitarian. A design patent would also be considered under this category. An industrial design consists of the creation of a shape, configuration or composition of pattern or color, or combination of pattern and color in three-dimensional form containing aesthetic value. An industrial design can be a two- or three-dimensional pattern used to produce a product, industrial commodity or handicraft. Under the Hague Agreement Concerning the International Deposit of Industrial Designs, a WIPO-administered treaty, a procedure for an international registration exists. An applicant can file for a single international deposit with WIPO or with the national office in a country party to the treaty. The design will then be protected in as many member countries of the treaty as desired.
In 2022, about 1.1 million industrial design applications were filed worldwide. This represents a decrease of 3% on 2021, marking a first drop in filings since 2014. In 2023, the number of applications rose again, with about 1.19 million design applications filed.
=== Hague top applicants ===
The Hague System for the International Registration of Industrial Designs provides an international mechanism that secures protection of up to 100 designs in multiple countries or regions, through a single international application. International design applications are filed directly through WIPO using the WIPO Hague System. The domestic legal framework of each designated contracting party governs the design protection provided by the resulting international registrations. The Hague System does not require the applicant to file a national or regional design application.
== Examples of industrial design ==
A number of industrial designers have made such a significant impact on culture and daily life that their work is documented by historians of social science. Alvar Aalto, renowned as an architect, also designed a significant number of household items, such as chairs, stools, lamps, a tea-cart, and vases. Raymond Loewy was a prolific American designer who is responsible for the Royal Dutch Shell corporate logo, the original BP logo (in use until 2000), the PRR S1 steam locomotive, the Studebaker Starlight (including the later bulletnose), as well as Schick electric razors, Electrolux refrigerators, short-wave radios, Le Creuset French ovens, and a complete line of modern furniture, among many other items.
Richard Teague, who spent most of his career with the American Motors Corporation, originated the concept of using interchangeable body panels so as to create a wide array of different vehicles using the same stampings. He was responsible for such unique automotive designs as the Pacer, Gremlin, Matador coupe, Jeep Cherokee, and the complete interior of the Eagle Premier.
Milwaukee's Brooks Stevens was best known for his Milwaukee Road Skytop Lounge car and Oscar Mayer Wienermobile designs, among others.
Viktor Schreckengost designed bicycles manufactured by Murray bicycles for Murray and Sears, Roebuck and Company. With engineer Ray Spiller, he designed the first truck with a cab-over-engine configuration, a design in use to this day. Schreckengost also founded The Cleveland Institute of Art's school of industrial design.
Oskar Barnack was a German optical engineer, precision mechanic, industrial designer, and the father of 35mm photography. He developed the Leica, which became the hallmark for photography for 50 years, and remains a high-water mark for mechanical and optical design.
Charles and Ray Eames were most famous for their pioneering furniture designs, such as the Eames Lounge Chair Wood and Eames Lounge Chair. Other influential designers included Henry Dreyfuss, Eliot Noyes, John Vassos, and Russel Wright.
Dieter Rams is a German industrial designer closely associated with the consumer products company Braun and the Functionalist school of industrial design.
German industrial designer Luigi Colani, who designed cars for automobile manufacturers including Fiat, Alfa Romeo, Lancia, Volkswagen, and BMW, was also known to the general public for his unconventional approach to industrial design. He had expanded in numerous areas ranging from mundane household items, instruments and furniture to trucks, uniforms and entire rooms. A grand piano created by Colani, the Pegasus, is manufactured and sold by the Schimmel piano company.
Many of Apple's recent products were designed by Sir Jonathan Ive.
== See also ==
== References ==
=== Sources ===
Barnwell, Maurice. Design, Creativity and Culture, Black Dog, 2011, ISBN 978 1 907317 408
Barnwell, Maurice. Design Evolution: Big Bang to Big Data,Toronto, 2014. ISBN 978-0-9937396-0-6
Baynes, Ken (1991). "Forms of Representation". In Pirovano, Carlo (ed.). History of Industrial Design. Vol. 1. Milan: Electa. pp. 108–127. OCLC 32885051.
Benton, Charlotte (2000). "Design and Industry". In Kemp, Martin (ed.). The Oxford History of Western Art. Oxford: Oxford University Press. pp. 380–383. ISBN 0198600127.
Forty, Adrian. Objects of Desire: Design and Society Since 1750. Thames Hudson, May 1992. ISBN 978-0-500-27412-5
Heskett, John (1980). Industrial Design. Thames & Hudson. ISBN 0500201811.
Kirkham, Pat (1999). Industrial design. Grove Art Online. Oxford University Press.
Mayall, WH, Industrial Design for Engineers, London: Iliffe Books, 1967, ISBN 978-0592042053
Mayall, WH, Machines and Perception in Industrial Design, London: Studio Vista, 1968, ISBN 978-0289279168
Meikle, Jeffrey. Twentieth Century Limited: Industrial Design engineering in America, 1925 - 1939, Philadelphia: Temple University Press, 1979 ISBN 978-0877222460
Noblet, Jocelyn de (1993). "Design in Progress". In Noblet, Jocelyn de (ed.). Industrial design: reflection of a century. Paris: Flammarion/APCI. pp. 21–25. ISBN 2080135392.
Pulos, Arthur (1983). American Design Ethic: A History of Industrial Design. MIT Press. ISBN 9780262368100.
== External links ==
Doodles, Drafts and Designs: Industrial Drawings from the Smithsonian (2004) Smithsonian Institution Libraries
Hague Yearly Review related to industrial design Hague applications | Wikipedia/Industrial_design_engineering |
Industrial engineering (IE) is concerned with the design, improvement and installation of integrated systems of people, materials, information, equipment and energy. It draws upon specialized knowledge and skill in the mathematical, physical, and social sciences together with the principles and methods of engineering analysis and design, to specify, predict, and evaluate the results to be obtained from such systems. Industrial engineering is a branch of engineering that focuses on optimizing complex processes, systems, and organizations by improving efficiency, productivity, and quality. It combines principles from engineering, mathematics, and business to design, analyze, and manage systems that involve people, materials, information, equipment, and energy. Industrial engineers aim to reduce waste, streamline operations, and enhance overall performance across various industries, including manufacturing, healthcare, logistics, and service sectors.
Industrial engineers are employed in numerous industries, such as automobile manufacturing, aerospace, healthcare, forestry, finance, leisure, and education. Industrial engineering combines the physical and social sciences together with engineering principles to improve processes and systems.
Several industrial engineering principles are followed to ensure the effective flow of systems, processes, and operations. Industrial engineers work to improve quality and productivity while simultaneously cutting waste. They use principles such as lean manufacturing, six sigma, information systems, process capability, and more.
These principles allow the creation of new systems, processes or situations for the useful coordination of labor, materials and machines. Depending on the subspecialties involved, industrial engineering may also overlap with, operations research, systems engineering, manufacturing engineering, production engineering, supply chain engineering, management science, engineering management, financial engineering, ergonomics or human factors engineering, safety engineering, logistics engineering, quality engineering or other related capabilities or fields.
== History ==
=== Origins ===
==== Industrial engineering ====
The origins of industrial engineering are generally traced back to the Industrial Revolution with the rise of factory systems and mass production. The fundamental concepts began to emerge through ideas like Adam Smith's division of labor and the implementation of interchangeable parts by Eli Whitney. The term "industrial engineer" is credited to James Gunn who proposed the need for such an engineer focused on production and cost analysis in 1901. However, Frederick Taylor is widely credited as the "father of industrial engineering" for his focus on scientific management, emphasizing time studies and standardized work methods, with his principles being published in 1911. Notably, Taylor established the first department dedicated to industrial engineering work, called "Elementary Rate Fixing," in 1885 with the goal of process improvement and productivity increase. Frank and Lillian Gilbreth further contributed significantly with their development of motion studies and therbligs for analyzing manual labor in the early 20th century. The early focus of the field was heavily on improving efficiency and productivity within manufacturing environments, driven in part by the call for cost reduction by engineering professionals, as highlighted by the first president of ASME in 1880. The formalization of the discipline continued with the founding of the American Institute of Industrial Engineering (AIIE) in 1948. In more recent years, industrial engineering has expanded beyond manufacturing to include areas like healthcare, project management, and supply chain optimization.
==== Systems Engineering ====
The origins of systems engineering as a recognized discipline can be traced back to World War II, where its principles began to emerge to manage the complexities of new war technologies. Although systems thinking predates this period, the analysis of the RAF Fighter Command C2 System during the Battle of Britain (even though the term wasn't yet invented) is considered an early example of high-caliber systems engineering. The first known public use of the term "systems engineering" occurred in March 1950 by Mervin J. Kelly of Bell Telephone Laboratories, who described it as crucial for defining new systems and guiding the application of research in creating new services. The first published paper specifically on the subject appeared in 1956 by Kenneth Schlager, who noted the growing importance of systems engineering due to increasing technological complexity and the formation of dedicated systems engineering groups. In 1957, E.W. Engstrom further elaborated on the concept, emphasizing the determination of objectives and the thorough consideration of all influencing factors as requirements for successful systems engineering. That same year also saw the publication of the first textbook on the subject, "Systems Engineering: An Introduction to the Design of Large-Scale Systems" by Goode and Mahol. Early practices of systems engineering were generally informal, transdisciplinary, and deeply rooted in the application domain. Following these initial mentions and publications, the field saw further development in the 1960s and 1970s, with figures like Arthur Hall defining traits of a systems engineer and viewing it as a comprehensive process. Despite its informal nature, systems engineering played a vital role in major achievements like the 1969 Apollo moon landing. A significant step towards formalization occurred in July 1969 with the introduction of the first formal systems engineering process, Military Standard (MIL-STD)-499: System Engineering Management, by the U.S. Air Force. This standard aimed to provide guidance for managing the systems engineering process and was later extended and updated. The need for formally trained systems engineers led to the formation of the National Council on Systems Engineering (NCOSE) in the late 1980s, which evolved into the International Council on Systems Engineering (INCOSE). INCOSE further contributed to the formalization of the field through publications like its journal "Systems Engineering" starting in 1994 and the first edition of the "Systems Engineering Handbook" in 1997. Additionally, organizations like NASA published their own systems engineering handbooks. In the 21st century, international standardization became a key aspect, with the International Standards Organization (ISO) publishing its first standard defining systems engineering application and management in 2005, further solidifying its standing as a formal discipline.
=== Pioneers ===
Frederick Taylor (1856–1915) is generally credited as the father of the industrial engineering discipline. He earned a degree in mechanical engineering from Stevens Institute of Technology and earned several patents from his inventions. Taylor is the author of many well-known works, including a book, The Principles of Scientific Management, which became a classic of management literature. It is considered one of the most influential management books of the 20th century. The book laid our three goals: to illustrate how the country loses through inefficiency, to show that the solution to inefficiency is systematic management, and to show that the best management rests on defined laws, rules, and principles that can be applied to all kinds of human activity. Taylor is remembered for developing the stopwatch time study. Taylor's findings set the foundation for industrial engineering.
Frank Gilbreth (1868-1924), along with his wife Lillian Gilbreth (1878-1972), also had a significant influence on the development of Industrial Engineering. Their work is housed at Purdue University. In 1907, Frank Gilbreth met Frederick Taylor, and he learned tremendously from Taylor’s work. Frank and Lillian created 18 kinds of elemental motions that make up a set of fundamental motions required for a worker to perform a manual operation or task. They named the elements therbligs, which are used in the study of motion in the workplace. These developments were the beginning of a much broader field known as human factors or ergonomics.
Through the efforts of Hugo Diemer, the first course on industrial engineering was offered as an elective at Pennsylvania State University in 1908. The first doctoral degree in industrial engineering was awarded in 1933 by Cornell University.
Henry Gantt (1861-1919) immersed himself in the growing movement of Taylorism. Gantt is best known for creating a management tool, the Gantt chart. Gantt charts display dependencies pictorially, which allows project managers to keep everything organized. They are studied in colleges and used by project managers around the world. In addition to the creation of the Gannt chart, Gantt had many other significant contributions to scientific management. He cared about worker incentives and the impact businesses had on society. Today, the American Society of Mechanical Engineers awards a Gantt Medal for “distinguished achievement in management and for service to the community.”
Henry Ford (1863-1947) further revolutionized factory production with the first installation of a moving assembly line. This innovation reduced the time it took to build a car from more than 12 hours to one hour and 33 minutes. This continuous-flow inspired production method introduced a new way of automobile manufacturing. Ford is also known for transforming the workweek schedule. He cut the typical six-day workweek to five and doubled the daily pay. Thus, creating the typical 40-hour workweek.
Total quality management (TQM) emerged in the 1940s and gained momentum after World War II. The term was coined to describe its Japanese-style management approach to quality improvement. Total quality management can be described as a management system for a customer-focused organization that engages all employees in continual improvement of the organization. Joseph Juran is credited with being a pioneer of TQM by teaching the concepts of controlling quality and managerial breakthrough.
The American Institute of Industrial Engineering was formed in 1948. The early work by F. W. Taylor and the Gilbreths was documented in papers presented to the American Society of Mechanical Engineers as interest grew from merely improving machine performance to the performance of the overall manufacturing process, most notably starting with the presentation by Henry R. Towne (1844–1924) of his paper The Engineer as An Economist (1886).
=== Modern practice ===
From 1960 to 1975, with the development of decision support systems in supply such as material requirements planning (MRP), one can emphasize the timing issue (inventory, production, compounding, transportation, etc.) of industrial organization. Israeli scientist Dr. Jacob Rubinovitz installed the CMMS program developed in IAI and Control-Data (Israel) in 1976 in South Africa and worldwide.
In the 1970s, with the penetration of Japanese management theories such as Kaizen and Kanban, Japan realized very high levels of quality and productivity. These theories improved issues of quality, delivery time, and flexibility. Companies in the west realized the great impact of Kaizen and started implementing their own continuous improvement programs. W. Edwards Deming made significant contributions in the minimization of variance starting in the 1950s and continuing to the end of his life.
In the 1990s, following the global industry globalization process, the emphasis was on supply chain management and customer-oriented business process design. The theory of constraints, developed by Israeli scientist Eliyahu M. Goldratt (1985), is also a significant milestone in the field.
In recent years (late 2000s to 2025), the traditional skills of industrial engineering, such as system optimization, process improvement, and efficiency management, remain essential. However, these foundational abilities are increasingly complemented by a deeper understanding of emerging technologies, such as artificial intelligence, machine learning, and IoT (Internet of Things). Proficiency in data analytics has become crucial, as it allows engineers to harness big data and derive insights that inform decision-making and innovation. Additionally, knowledge in fields such as cybersecurity, software development, and sustainable practices is becoming integral to the industrial engineering scope.
As we navigate beyond 2025, it is imperative for professionals across various industries to stay abreast of these advancements. The ongoing evolution of industrial engineering will undoubtedly open new career pathways and reshape existing roles. Companies and individuals must be proactive in adapting to these changes to harness the full potential of this dynamic field.
== Etymology ==
While originally applied to manufacturing, the use of industrial in industrial engineering can be somewhat misleading, since it has grown to encompass any methodical or quantitative approach to optimizing how a process, system, or organization operates. In fact, the industrial in industrial engineering means the industry in its broadest sense. People have changed the term industrial to broader terms such as industrial and manufacturing engineering, industrial and systems engineering, industrial engineering and operations research, or industrial engineering and management.
== Sub-disciplines ==
There are numerous sub-disciplines associated with industrial engineering, including the following a non-exhaustive list. While some industrial engineers focus exclusively on one of these sub-disciplines, many deal with a combination of sub-disciplines. The first 14 of these sub-disciplines come from the IISE Body of Knowledge. These are considered knowledge areas, and many of them contain an overlap of content.
Work design and measurement
Operations research and analysis
Engineering economic analysis
Facilities engineering and energy management
Quality engineering and reliability engineering
Ergonomics and human factors in engineering and design
Operations engineering and operations management
Supply chain management
Engineering management
Safety
Information engineering
Design and manufacturing engineering
Product design and product development
Systems design and systems engineering
Facilities engineering
Logistics
Systems engineering
Healthcare engineering
Project management
Financial engineering
== Education ==
Industrial engineering students take courses in work analysis and design, process design, human factors, facilities planning and layout, engineering economic analysis, production planning and control, systems engineering, computer utilization and simulation, operations research, quality control, automation, robotics, and productivity engineering.
Various universities offer Industrial Engineering degrees across the world. The Edwardson School of Industrial Engineering at Purdue University, the H. Milton Stewart School of Industrial and Systems Engineering at Georgia Institute of Technology, and the Department of Industrial and Operations Engineering at the University of Michigan are all named industrial engineering departments in the United States. Other universities include: Virginia Tech, Texas A&M, Northwestern University, University of Wisconsin–Madison, and the University of Southern California, and NC State University.
It is important to attend accredited universities because ABET accreditation ensures that graduates have met the educational requirements necessary to enter the profession. This quality of education is recognized internationally and prepares students for successful careers.
Internationally, industrial engineering degrees accredited within any member country of the Washington Accord enjoy equal accreditation within all other signatory countries, thus allowing engineers from one country to practice engineering professionally in any other.
Universities offer degrees at the bachelor, master, and doctoral levels.
=== Undergraduate curriculum ===
In the United States, the undergraduate degree earned is either a bachelor of science (BS) or a bachelor of science and engineering (BSE) in industrial engineering (IE). In South Africa, the undergraduate degree is a bachelor of engineering (BEng). Variations of the title include Industrial & Operations Engineering (IOE), and Industrial & Systems Engineering (ISE or ISyE).
The typical curriculum includes a broad math and science foundation spanning chemistry, physics, mechanics (i.e., statics, kinematics, and dynamics), materials science, computer science, electronics/circuits, engineering design, and the standard range of engineering mathematics (i.e., calculus, linear algebra, differential equations, statistics). For any engineering undergraduate program to be accredited, regardless of concentration, it must cover a largely similar span of such foundational work, which also overlaps heavily with the content tested on one or more engineering licensure exams in most jurisdictions.
The coursework specific to IE entails specialized courses in areas such as optimization, applied probability, stochastic modeling, design of experiments, statistical process control, simulation, manufacturing engineering, ergonomics/safety engineering, and engineering economics. Industrial engineering elective courses typically cover more specialized topics in areas such as manufacturing, supply chains and logistics, analytics and machine learning, production systems, human factors and industrial design, and service systems.
Certain business schools may offer programs with some overlapping relevance to IE, but the engineering programs are distinguished by a much more intensely quantitative focus, required engineering science electives, and the core math and science courses required of all engineering programs.
=== Graduate curriculum ===
The usual graduate degree earned is the master of science (MS), master of science and engineering (MSE) or master of engineering (MEng) in industrial engineering or various alternative related concentration titles.
Typical MS curricula may cover:
== See also ==
=== Notable Associations and Professional Organizations ===
Institute of Industrial Engineers (IISE)
Human Factors and Ergonomics Society (HFES)
Society of Manufacturing Engineers (SME)
American Production and Inventory Control Society (APICS)
Institute for Operations Research and the Management Sciences (INFORMS)
American Society for Quality (ASQ)
The International Council on Systems Engineering (INCOSE)
=== Notable Universities ===
List of Universities with Industrial Engineering Programs
=== Notable Conferences ===
International Conference on Mechanical Industrial & Energy Engineering
IISE Annual Conference
INFORMS Annual Conference
=== Related topics ===
== Notes ==
== Further reading ==
Badiru, A. (Ed.) (2005). Handbook of industrial and systems engineering. CRC Press. ISBN 0-8493-2719-9.
B. S. Blanchard and Fabrycky, W. (2005). Systems Engineering and Analysis (4th Edition). Prentice-Hall. ISBN 0-13-186977-9.
Salvendy, G. (Ed.) (2001). Handbook of industrial engineering: Technology and operations management. Wiley-Interscience. ISBN 0-471-33057-4.
Turner, W. et al. (1992). Introduction to industrial and systems engineering (Third edition). Prentice Hall. ISBN 0-13-481789-3.
Eliyahu M. Goldratt, Jeff Cox (1984). The Goal North River Press; 2nd Rev edition (1992). ISBN 0-88427-061-0; 20th Anniversary edition (2004) ISBN 0-88427-178-1
Miller, Doug, Towards Sustainable Labour Costing in UK Fashion Retail (February 5, 2013). doi:10.2139/ssrn.2212100
Malakooti, B. (2013). Operations and Production Systems with Multiple Objectives. John Wiley & Sons.ISBN 978-1-118-58537-5
Systems Engineering Body of Knowledge (SEBoK)
Traditional Engineering
Master of Engineering Administration (MEA)
Kambhampati, Venkata Satya Surya Narayana Rao (2017). "Principles of Industrial Engineering" IIE Annual Conference. Proceedings; Norcross (2017): 890-895.Principles of Industrial Engineering - ProQuest
IISE Body of Knowledge
== External links ==
Media related to Industrial engineering at Wikimedia Commons | Wikipedia/Industrial_engineer |
IEEE 802.11i-2004, or 802.11i for short, is an amendment to the original IEEE 802.11, implemented as Wi-Fi Protected Access II (WPA2). The draft standard was ratified on 24 June 2004. This standard specifies security mechanisms for wireless networks, replacing the short Authentication and privacy clause of the original standard with a detailed Security clause. In the process, the amendment deprecated broken Wired Equivalent Privacy (WEP), while it was later incorporated into the published IEEE 802.11-2007 standard.
== Replacement of WEP ==
802.11i supersedes the previous security specification, Wired Equivalent Privacy (WEP), which was shown to have security vulnerabilities. Wi-Fi Protected Access (WPA) had previously been introduced by the Wi-Fi Alliance as an intermediate solution to WEP insecurities. WPA implemented a subset of a draft of 802.11i. The Wi-Fi Alliance refers to their approved, interoperable implementation of the full 802.11i as WPA2, also called RSN (Robust Security Network). 802.11i makes use of the Advanced Encryption Standard (AES) block cipher, whereas WEP and WPA use the RC4 stream cipher.
== Protocol operation ==
IEEE 802.11i enhances IEEE 802.11-1999 by providing a Robust Security Network (RSN) with two new protocols: the four-way handshake and the group key handshake. These utilize the authentication services and port access control described in IEEE 802.1X to establish and change the appropriate cryptographic keys. The RSN is a security network that only allows the creation of robust security network associations (RSNAs), which are a type of association used by a pair of stations (STAs) if the procedure to establish authentication or association between them includes the 4-Way Handshake.
The standard also provides two RSNA data confidentiality and integrity protocols, TKIP and CCMP, with implementation of CCMP being mandatory since the confidentiality and integrity mechanisms of TKIP are not as robust as those of CCMP. The main purpose to implement TKIP was that the algorithm should be implementable within the capabilities of most of the old devices supporting only WEP.
The initial authentication process is carried out either using a pre-shared key (PSK), or following an EAP exchange through 802.1X (known as EAPOL, which requires the presence of an authentication server). This process ensures that the client station (STA) is authenticated with the access point (AP). After the PSK or 802.1X authentication, a shared secret key is generated, called the Pairwise Master Key (PMK). In PSK authentication, the PMK is actually the PSK, which is typically derived from the WiFi password by putting it through a key derivation function that uses SHA-1 as the cryptographic hash function. If an 802.1X EAP exchange was carried out, the PMK is derived from the EAP parameters provided by the authentication server.
=== Four-way handshake ===
The four-way handshake is designed so that the access point (or authenticator) and wireless client (or supplicant) can independently prove to each other that they know the PSK/PMK, without ever disclosing the key. Instead of disclosing the key, the access point (AP) and client encrypt messages to each other—that can only be decrypted by using the PMK that they already share—and if decryption of the messages was successful, this proves knowledge of the PMK. The four-way handshake is critical for protection of the PMK from malicious access points—for example, an attacker's SSID impersonating a real access point—so that the client never has to tell the access point its PMK.
The PMK is designed to last the entire session and should be exposed as little as possible; therefore, keys to encrypt the traffic need to be derived. A four-way handshake is used to establish another key called the Pairwise Transient Key (PTK). The PTK is generated by concatenating the following attributes: PMK, AP nonce (ANonce), STA nonce (SNonce), AP MAC address, and STA MAC address. The product is then put through a pseudo-random function. The handshake also yields the GTK (Group Temporal Key), used to decrypt multicast and broadcast traffic.
The actual messages exchanged during the handshake are depicted in the figure and explained below (all messages are sent as EAPOL-Key frames):
The AP sends a nonce-value (ANonce) to the STA together with a Key Replay Counter, which is a number that is used to match each pair of messages sent, and discard replayed messages. The STA now has all the attributes to construct the PTK.
The STA sends its own nonce-value (SNonce) to the AP together with a Message Integrity Code (MIC), including authentication, which is really a Message Authentication and Integrity Code (MAIC), and the Key Replay Counter which will be the same as Message 1, to allow AP to match the right Message 1.
The AP verifies Message 2, by checking MIC, RSN, ANonce and Key Replay Counter Field, and if valid constructs and sends the GTK with another MIC.
The STA verifies Message 3, by checking MIC and Key Replay Counter Field, and if valid sends a confirmation to the AP.
=== Group key handshake ===
The Group Temporal Key (GTK) used in the network may need to be updated due to the expiration of a preset timer. When a device leaves the network, the GTK also needs to be updated. This is to prevent the device from receiving any more multicast or broadcast messages from the AP.
To handle the updating, 802.11i defines a Group Key Handshake that consists of a two-way handshake:
The AP sends the new GTK to each STA in the network. The GTK is encrypted using the KEK assigned to that STA, and protects the data from tampering, by use of a MIC.
The STA acknowledges the new GTK and replies to the AP.
== CCMP overview ==
CCMP is based on the Counter with CBC-MAC (CCM) mode of the AES encryption algorithm. CCM combines CTR for confidentiality and CBC-MAC for authentication and integrity. CCM protects the integrity of both the MPDU Data field and selected portions of the IEEE 802.11 MPDU header.
== Key hierarchy ==
RSNA defines two key hierarchies:
Pairwise key hierarchy, to protect unicast traffic
GTK, a hierarchy consisting of a single key to protect multicast and broadcast traffic
The description of the key hierarchies uses the following two functions:
L(Str, F, L) - From Str starting from the left, extract bits F through F+L–1.
PRF-n - Pseudo-random function producing n bits of output, there are the 128, 192, 256, 384 and 512 versions, each of these output these number of bits.
The pairwise key hierarchy utilizes PRF-384 or PRF-512 to derive session-specific keys from a PMK, generating a PTK, which gets partitioned into a KCK and a KEK plus all the temporal keys used by the MAC to protect unicast communication.
The GTK shall be a random number which also gets generated by using PRF-n, usually PRF-128 or PRF-256, in this model, the group key hierarchy takes a GMK (Group Master Key) and generates a GTK.
== MAC frame formats ==
=== Frame Control field ===
=== Protected Frame field ===
"The Protected Frame field is 1 bit in length. The Protected Frame field is set to 1 if the Frame Body field contains information that has been processed by a cryptographic encapsulation algorithm. The Protected Frame field is set to 1 only within data frames of type Data and within management frames of type Management, subtype Authentication. The Protected Frame field is set to 0 in all other frames. When the bit Protected Frame field is set to 1 in a data frame, the Frame Body field is protected utilizing the cryptographic encapsulation algorithm and expanded as defined in Clause 8. Only WEP is allowed as the cryptographic encapsulation algorithm for management frames of subtype Authentication."
== See also ==
KRACK
WLAN Authentication and Privacy Infrastructure (WAPI), China's centralized wireless security method
IEEE 802.1AE MACsec
== References ==
General
== External links ==
Vulnerability in the WPA2 protocol, hole196 [1] Archived 2015-11-13 at the Wayback Machine, [2] | Wikipedia/Robust_Security_Network |
Engineering is the practice of using natural science, mathematics, and the engineering design process to solve problems within technology, increase efficiency and productivity, and improve systems. Modern engineering comprises many subfields which include designing and improving infrastructure, machinery, vehicles, electronics, materials, and energy systems.
The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis for applications of mathematics and science. See glossary of engineering.
The word engineering is derived from the Latin ingenium.
== Definition ==
The American Engineers' Council for Professional Development (the predecessor of the Accreditation Board for Engineering and Technology aka ABET) has defined "engineering" as:
The creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behavior under specific operating conditions; all as respects an intended function, economics of operation and safety to life and property.
== History ==
Engineering has existed since ancient times, when humans devised inventions such as the wedge, lever, wheel and pulley, etc.
The term engineering is derived from the word engineer, which itself dates back to the 14th century when an engine'er (literally, one who builds or operates a siege engine) referred to "a constructor of military engines". In this context, now obsolete, an "engine" referred to a military machine, i.e., a mechanical contraption used in war (for example, a catapult). Notable examples of the obsolete usage which have survived to the present day are military engineering corps, e.g., the U.S. Army Corps of Engineers.
The word "engine" itself is of even older origin, ultimately deriving from the Latin ingenium (c. 1250), meaning "innate quality, especially mental power, hence a clever invention."
Later, as the design of civilian structures, such as bridges and buildings, matured as a technical discipline, the term civil engineering entered the lexicon as a way to distinguish between those specializing in the construction of such non-military projects and those involved in the discipline of military engineering.
=== Ancient era ===
The pyramids in ancient Egypt, ziggurats of Mesopotamia, the Acropolis and Parthenon in Greece, the Roman aqueducts, Via Appia and Colosseum, Teotihuacán, and the Brihadeeswarar Temple of Thanjavur, among many others, stand as a testament to the ingenuity and skill of ancient civil and military engineers. Other monuments, no longer standing, such as the Hanging Gardens of Babylon and the Pharos of Alexandria, were important engineering achievements of their time and were considered among the Seven Wonders of the Ancient World.
The six classic simple machines were known in the ancient Near East. The wedge and the inclined plane (ramp) were known since prehistoric times. The wheel, along with the wheel and axle mechanism, was invented in Mesopotamia (modern Iraq) during the 5th millennium BC. The lever mechanism first appeared around 5,000 years ago in the Near East, where it was used in a simple balance scale, and to move large objects in ancient Egyptian technology. The lever was also used in the shadoof water-lifting device, the first crane machine, which appeared in Mesopotamia c. 3000 BC, and then in ancient Egyptian technology c. 2000 BC. The earliest evidence of pulleys date back to Mesopotamia in the early 2nd millennium BC, and ancient Egypt during the Twelfth Dynasty (1991–1802 BC). The screw, the last of the simple machines to be invented, first appeared in Mesopotamia during the Neo-Assyrian period (911–609) BC. The Egyptian pyramids were built using three of the six simple machines, the inclined plane, the wedge, and the lever, to create structures like the Great Pyramid of Giza.
The earliest civil engineer known by name is Imhotep. As one of the officials of the Pharaoh, Djosèr, he probably designed and supervised the construction of the Pyramid of Djoser (the Step Pyramid) at Saqqara in Egypt around 2630–2611 BC. The earliest practical water-powered machines, the water wheel and watermill, first appeared in the Persian Empire, in what are now Iraq and Iran, by the early 4th century BC.
Kush developed the Sakia during the 4th century BC, which relied on animal power instead of human energy. Hafirs were developed as a type of reservoir in Kush to store and contain water as well as boost irrigation. Sappers were employed to build causeways during military campaigns. Kushite ancestors built speos during the Bronze Age between 3700 and 3250 BC. Bloomeries and blast furnaces were also created during the 7th centuries BC in Kush.
Ancient Greece developed machines in both civilian and military domains. The Antikythera mechanism, an early known mechanical analog computer, and the mechanical inventions of Archimedes, are examples of Greek mechanical engineering. Some of Archimedes' inventions, as well as the Antikythera mechanism, required sophisticated knowledge of differential gearing or epicyclic gearing, two key principles in machine theory that helped design the gear trains of the Industrial Revolution, and are widely used in fields such as robotics and automotive engineering.
Ancient Chinese, Greek, Roman and Hunnic armies employed military machines and inventions such as artillery which was developed by the Greeks around the 4th century BC, the trireme, the ballista and the catapult, the trebuchet by Chinese circa 6th-5th century BCE.
=== Middle Ages ===
The earliest practical wind-powered machines, the windmill and wind pump, first appeared in the Muslim world during the Islamic Golden Age, in what are now Iran, Afghanistan, and Pakistan, by the 9th century AD. The earliest practical steam-powered machine was a steam jack driven by a steam turbine, described in 1551 by Taqi al-Din Muhammad ibn Ma'ruf in Ottoman Egypt.
The cotton gin was invented in India by the 6th century AD, and the spinning wheel was invented in the Islamic world by the early 11th century, both of which were fundamental to the growth of the cotton industry. The spinning wheel was also a precursor to the spinning jenny, which was a key development during the early Industrial Revolution in the 18th century.
The earliest programmable machines were developed in the Muslim world. A music sequencer, a programmable musical instrument, was the earliest type of programmable machine. The first music sequencer was an automated flute player invented by the Banu Musa brothers, described in their Book of Ingenious Devices, in the 9th century. In 1206, Al-Jazari invented programmable automata/robots. He described four automaton musicians, including drummers operated by a programmable drum machine, where they could be made to play different rhythms and different drum patterns.
Before the development of modern engineering, mathematics was used by artisans and craftsmen, such as millwrights, clockmakers, instrument makers and surveyors. Aside from these professions, universities were not believed to have had much practical significance to technology.: 32
A standard reference for the state of mechanical arts during the Renaissance is given in the mining engineering treatise De re metallica (1556), which also contains sections on geology, mining, and chemistry. De re metallica was the standard chemistry reference for the next 180 years.
=== Modern era ===
The science of classical mechanics, sometimes called Newtonian mechanics, formed the scientific basis of much of modern engineering. With the rise of engineering as a profession in the 18th century, the term became more narrowly applied to fields in which mathematics and science were applied to these ends. Similarly, in addition to military and civil engineering, the fields then known as the mechanic arts became incorporated into engineering.
Canal building was an important engineering work during the early phases of the Industrial Revolution.
John Smeaton was the first self-proclaimed civil engineer and is often regarded as the "father" of civil engineering. He was an English civil engineer responsible for the design of bridges, canals, harbors, and lighthouses. He was also a capable mechanical engineer and an eminent physicist. Using a model water wheel, Smeaton conducted experiments for seven years, determining ways to increase efficiency.: 127 Smeaton introduced iron axles and gears to water wheels.: 69 Smeaton also made mechanical improvements to the Newcomen steam engine. Smeaton designed the third Eddystone Lighthouse (1755–59) where he pioneered the use of 'hydraulic lime' (a form of mortar which will set under water) and developed a technique involving dovetailed blocks of granite in the building of the lighthouse. He is important in the history, rediscovery of, and development of modern cement, because he identified the compositional requirements needed to obtain "hydraulicity" in lime; work which led ultimately to the invention of Portland cement.
Applied science led to the development of the steam engine. The sequence of events began with the invention of the barometer and the measurement of atmospheric pressure by Evangelista Torricelli in 1643, demonstration of the force of atmospheric pressure by Otto von Guericke using the Magdeburg hemispheres in 1656, laboratory experiments by Denis Papin, who built experimental model steam engines and demonstrated the use of a piston, which he published in 1707. Edward Somerset, 2nd Marquess of Worcester published a book of 100 inventions containing a method for raising waters similar to a coffee percolator. Samuel Morland, a mathematician and inventor who worked on pumps, left notes at the Vauxhall Ordinance Office on a steam pump design that Thomas Savery read. In 1698 Savery built a steam pump called "The Miner's Friend". It employed both vacuum and pressure. Iron merchant Thomas Newcomen, who built the first commercial piston steam engine in 1712, was not known to have any scientific training.: 32
The application of steam-powered cast iron blowing cylinders for providing pressurized air for blast furnaces lead to a large increase in iron production in the late 18th century. The higher furnace temperatures made possible with steam-powered blast allowed for the use of more lime in blast furnaces, which enabled the transition from charcoal to coke. These innovations lowered the cost of iron, making horse railways and iron bridges practical. The puddling process, patented by Henry Cort in 1784 produced large scale quantities of wrought iron. Hot blast, patented by James Beaumont Neilson in 1828, greatly lowered the amount of fuel needed to smelt iron. With the development of the high pressure steam engine, the power to weight ratio of steam engines made practical steamboats and locomotives possible. New steel making processes, such as the Bessemer process and the open hearth furnace, ushered in an area of heavy engineering in the late 19th century.
One of the most famous engineers of the mid-19th century was Isambard Kingdom Brunel, who built railroads, dockyards and steamships.
The Industrial Revolution created a demand for machinery with metal parts, which led to the development of several machine tools. Boring cast iron cylinders with precision was not possible until John Wilkinson invented his boring machine, which is considered the first machine tool. Other machine tools included the screw cutting lathe, milling machine, turret lathe and the metal planer. Precision machining techniques were developed in the first half of the 19th century. These included the use of gigs to guide the machining tool over the work and fixtures to hold the work in the proper position. Machine tools and machining techniques capable of producing interchangeable parts lead to large scale factory production by the late 19th century.
The United States Census of 1850 listed the occupation of "engineer" for the first time with a count of 2,000. There were fewer than 50 engineering graduates in the U.S. before 1865. The first PhD in engineering (technically, applied science and engineering) awarded in the United States went to Josiah Willard Gibbs at Yale University in 1863; it was also the second PhD awarded in science in the U.S. In 1870 there were a dozen U.S. mechanical engineering graduates, with that number increasing to 43 per year in 1875. In 1890, there were 6,000 engineers in civil, mining, mechanical and electrical. There was no chair of applied mechanism and applied mechanics at Cambridge until 1875, and no chair of engineering at Oxford until 1907. Germany established technical universities earlier.
The foundations of electrical engineering in the 1800s included the experiments of Alessandro Volta, Michael Faraday, Georg Ohm and others and the invention of the electric telegraph in 1816 and the electric motor in 1872. The theoretical work of James Maxwell (see: Maxwell's equations) and Heinrich Hertz in the late 19th century gave rise to the field of electronics. The later inventions of the vacuum tube and the transistor further accelerated the development of electronics to such an extent that electrical and electronics engineers currently outnumber their colleagues of any other engineering specialty.
Chemical engineering developed in the late nineteenth century. Industrial scale manufacturing demanded new materials and new processes and by 1880 the need for large scale production of chemicals was such that a new industry was created, dedicated to the development and large scale manufacturing of chemicals in new industrial plants. The role of the chemical engineer was the design of these chemical plants and processes. Originally deriving from the manufacture of ceramics and its putative derivative metallurgy, materials science is one of the oldest forms of engineering. Modern materials science evolved directly from metallurgy, which itself evolved from the use of fire. Important elements of modern materials science were products of the Space Race; the understanding and engineering of the metallic alloys, and silica and carbon materials, used in building space vehicles enabling the exploration of space. Materials science has driven, and been driven by, the development of revolutionary technologies such as rubbers, plastics, semiconductors, and biomaterials.
Aeronautical engineering deals with aircraft design process design while aerospace engineering is a more modern term that expands the reach of the discipline by including spacecraft design. Its origins can be traced back to the aviation pioneers around the start of the 20th century although the work of Sir George Cayley has recently been dated as being from the last decade of the 18th century. Early knowledge of aeronautical engineering was largely empirical with some concepts and skills imported from other branches of engineering. Only a decade after the successful flights by the Wright brothers, there was extensive development of aeronautical engineering through development of military aircraft that were used in World War I. Meanwhile, research to provide fundamental background science continued by combining theoretical physics with experiments.
== Branches of engineering ==
Engineering is a broad discipline that is often broken down into several sub-disciplines. Although most engineers will usually be trained in a specific discipline, some engineers become multi-disciplined through experience. Engineering is often characterized as having five main branches: chemical engineering, civil engineering, electrical engineering, materials science and engineering, and mechanical engineering.
Below is a list of recognized branches of engineering. There are additional sub-disciplines as well.
== Interdisciplinary engineering ==
Interdisciplinary engineering draws from more than one of the principle branches of the practice. Historically, naval engineering and mining engineering were major branches. Other engineering fields are manufacturing engineering, acoustical engineering, corrosion engineering, instrumentation and control, automotive, information engineering, petroleum, systems, audio, software, architectural, biosystems, and textile engineering. These and other branches of engineering are represented in the 36 licensed member institutions of the UK Engineering Council.
New specialties sometimes combine with the traditional fields and form new branches – for example, Earth systems engineering and management involves a wide range of subject areas including engineering studies, environmental science, engineering ethics and philosophy of engineering.
== Practice ==
One who practices engineering is called an engineer, and those licensed to do so may have more formal designations such as Professional Engineer, Chartered Engineer, Incorporated Engineer, Ingenieur, European Engineer, or Designated Engineering Representative.
== Methodology ==
In the engineering design process, engineers apply mathematics and sciences such as physics to find novel solutions to problems or to improve existing solutions. Engineers need proficient knowledge of relevant sciences for their design projects. As a result, many engineers continue to learn new material throughout their careers.
If multiple solutions exist, engineers weigh each design choice based on their merit and choose the solution that best matches the requirements. The task of the engineer is to identify, understand, and interpret the constraints on a design in order to yield a successful result. It is generally insufficient to build a technically successful product, rather, it must also meet further requirements.
Constraints may include available resources, physical, imaginative or technical limitations, flexibility for future modifications and additions, and other factors, such as requirements for cost, safety, marketability, productivity, and serviceability. By understanding the constraints, engineers derive specifications for the limits within which a viable object or system may be produced and operated.
=== Problem solving ===
Engineers use their knowledge of science, mathematics, logic, economics, and appropriate experience or tacit knowledge to find suitable solutions to a particular problem. Creating an appropriate mathematical model of a problem often allows them to analyze it (sometimes definitively), and to test potential solutions.
More than one solution to a design problem usually exists so the different design choices have to be evaluated on their merits before the one judged most suitable is chosen. Genrich Altshuller, after gathering statistics on a large number of patents, suggested that compromises are at the heart of "low-level" engineering designs, while at a higher level the best design is one which eliminates the core contradiction causing the problem.
Engineers typically attempt to predict how well their designs will perform to their specifications prior to full-scale production. They use, among other things: prototypes, scale models, simulations, destructive tests, nondestructive tests, and stress tests. Testing ensures that products will perform as expected but only in so far as the testing has been representative of use in service. For products, such as aircraft, that are used differently by different users failures and unexpected shortcomings (and necessary design changes) can be expected throughout the operational life of the product.
Engineers take on the responsibility of producing designs that will perform as well as expected and, except those employed in specific areas of the arms industry, will not harm people. Engineers typically include a factor of safety in their designs to reduce the risk of unexpected failure.
The study of failed products is known as forensic engineering. It attempts to identify the cause of failure to allow a redesign of the product and so prevent a re-occurrence. Careful analysis is needed to establish the cause of failure of a product. The consequences of a failure may vary in severity from the minor cost of a machine breakdown to large loss of life in the case of accidents involving aircraft and large stationary structures like buildings and dams.
=== Computer use ===
As with all modern scientific and technological endeavors, computers and software play an increasingly important role. As well as the typical business application software there are a number of computer aided applications (computer-aided technologies) specifically for engineering. Computers can be used to generate models of fundamental physical processes, which can be solved using numerical methods.
One of the most widely used design tools in the profession is computer-aided design (CAD) software. It enables engineers to create 3D models, 2D drawings, and schematics of their designs. CAD together with digital mockup (DMU) and CAE software such as finite element method analysis or analytic element method allows engineers to create models of designs that can be analyzed without having to make expensive and time-consuming physical prototypes.
These allow products and components to be checked for flaws; assess fit and assembly; study ergonomics; and to analyze static and dynamic characteristics of systems such as stresses, temperatures, electromagnetic emissions, electrical currents and voltages, digital logic levels, fluid flows, and kinematics. Access and distribution of all this information is generally organized with the use of product data management software.
There are also many tools to support specific engineering tasks such as computer-aided manufacturing (CAM) software to generate CNC machining instructions; manufacturing process management software for production engineering; EDA for printed circuit board (PCB) and circuit schematics for electronic engineers; MRO applications for maintenance management; and Architecture, engineering and construction (AEC) software for civil engineering.
In recent years the use of computer software to aid the development of goods has collectively come to be known as product lifecycle management (PLM).
== Social context ==
The engineering profession engages in a range of activities, from collaboration at the societal level, and smaller individual projects. Almost all engineering projects are obligated to a funding source: a company, a set of investors, or a government. The types of engineering that are less constrained by such a funding source, are pro bono, and open-design engineering.
Engineering has interconnections with society, culture and human behavior. Most products and constructions used by modern society, are influenced by engineering. Engineering activities have an impact on the environment, society, economies, and public safety.
Engineering projects can be controversial. Examples from different engineering disciplines include: the development of nuclear weapons, the Three Gorges Dam, the design and use of sport utility vehicles and the extraction of oil. In response, some engineering companies have enacted serious corporate and social responsibility policies.
The attainment of many of the Millennium Development Goals requires the achievement of sufficient engineering capacity to develop infrastructure and sustainable technological development.
Overseas development and relief NGOs make considerable use of engineers, to apply solutions in disaster and development scenarios. Some charitable organizations use engineering directly for development:
Engineers Without Borders
Engineers Against Poverty
Registered Engineers for Disaster Relief
Engineers for a Sustainable World
Engineering for Change
Engineering Ministries International
Engineering companies in more developed economies face challenges with regard to the number of engineers being trained, compared with those retiring. This problem is prominent in the UK where engineering has a poor image and low status. There are negative economic and political issues that this can cause, as well as ethical issues. It is agreed the engineering profession faces an "image crisis". The UK holds the most engineering companies compared to other European countries, together with the United States.
=== Code of ethics ===
Many engineering societies have established codes of practice and codes of ethics to guide members and inform the public at large. The National Society of Professional Engineers code of ethics states:
Engineering is an important and learned profession. As members of this profession, engineers are expected to exhibit the highest standards of honesty and integrity. Engineering has a direct and vital impact on the quality of life for all people. Accordingly, the services provided by engineers require honesty, impartiality, fairness, and equity, and must be dedicated to the protection of the public health, safety, and welfare. Engineers must perform under a standard of professional behavior that requires adherence to the highest principles of ethical conduct.
In Canada, engineers wear the Iron Ring as a symbol and reminder of the obligations and ethics associated with their profession.
== Relationships with other disciplines ==
=== Science ===
Scientists study the world as it is; engineers create the world that has never been.
There exists an overlap between the sciences and engineering practice; in engineering, one applies science. Both areas of endeavor rely on accurate observation of materials and phenomena. Both use mathematics and classification criteria to analyze and communicate observations.
Scientists may also have to complete engineering tasks, such as designing experimental apparatus or building prototypes. Conversely, in the process of developing technology, engineers sometimes find themselves exploring new phenomena, thus becoming, for the moment, scientists or more precisely "engineering scientists".
In the book What Engineers Know and How They Know It, Walter Vincenti asserts that engineering research has a character different from that of scientific research. First, it often deals with areas in which the basic physics or chemistry are well understood, but the problems themselves are too complex to solve in an exact manner.
There is a "real and important" difference between engineering and physics as similar to any science field has to do with technology. Physics is an exploratory science that seeks knowledge of principles while engineering uses knowledge for practical applications of principles. The former equates an understanding into a mathematical principle while the latter measures variables involved and creates technology. For technology, physics is an auxiliary and in a way technology is considered as applied physics. Though physics and engineering are interrelated, it does not mean that a physicist is trained to do an engineer's job. A physicist would typically require additional and relevant training. Physicists and engineers engage in different lines of work. But PhD physicists who specialize in sectors of engineering physics and applied physics are titled as Technology officer, R&D Engineers and System Engineers.
An example of this is the use of numerical approximations to the Navier–Stokes equations to describe aerodynamic flow over an aircraft, or the use of the finite element method to calculate the stresses in complex components. Second, engineering research employs many semi-empirical methods that are foreign to pure scientific research, one example being the method of parameter variation.
As stated by Fung et al. in the revision to the classic engineering text Foundations of Solid Mechanics:
Engineering is quite different from science. Scientists try to understand nature. Engineers try to make things that do not exist in nature. Engineers stress innovation and invention. To embody an invention the engineer must put his idea in concrete terms, and design something that people can use. That something can be a complex system, device, a gadget, a material, a method, a computing program, an innovative experiment, a new solution to a problem, or an improvement on what already exists. Since a design has to be realistic and functional, it must have its geometry, dimensions, and characteristics data defined. In the past engineers working on new designs found that they did not have all the required information to make design decisions. Most often, they were limited by insufficient scientific knowledge. Thus they studied mathematics, physics, chemistry, biology and mechanics. Often they had to add to the sciences relevant to their profession. Thus engineering sciences were born.
Although engineering solutions make use of scientific principles, engineers must also take into account safety, efficiency, economy, reliability, and constructability or ease of fabrication as well as the environment, ethical and legal considerations such as patent infringement or liability in the case of failure of the solution.
=== Medicine and biology ===
The study of the human body, albeit from different directions and for different purposes, is an important common link between medicine and some engineering disciplines. Medicine aims to sustain, repair, enhance and even replace functions of the human body, if necessary, through the use of technology.
Modern medicine can replace several of the body's functions through the use of artificial organs and can significantly alter the function of the human body through artificial devices such as, for example, brain implants and pacemakers. The fields of bionics and medical bionics are dedicated to the study of synthetic implants pertaining to natural systems.
Conversely, some engineering disciplines view the human body as a biological machine worth studying and are dedicated to emulating many of its functions by replacing biology with technology. This has led to fields such as artificial intelligence, neural networks, fuzzy logic, and robotics. There are also substantial interdisciplinary interactions between engineering and medicine.
Both fields provide solutions to real world problems. This often requires moving forward before phenomena are completely understood in a more rigorous scientific sense and therefore experimentation and empirical knowledge is an integral part of both.
Medicine, in part, studies the function of the human body. The human body, as a biological machine, has many functions that can be modeled using engineering methods.
The heart for example functions much like a pump, the skeleton is like a linked structure with levers, the brain produces electrical signals etc. These similarities as well as the increasing importance and application of engineering principles in medicine, led to the development of the field of biomedical engineering that uses concepts developed in both disciplines.
Newly emerging branches of science, such as systems biology, are adapting analytical tools traditionally used for engineering, such as systems modeling and computational analysis, to the description of biological systems.
=== Art ===
There are connections between engineering and art, for example, architecture, landscape architecture and industrial design (even to the extent that these disciplines may sometimes be included in a university's Faculty of Engineering).
The Art Institute of Chicago, for instance, held an exhibition about the art of NASA's aerospace design. Robert Maillart's bridge design is perceived by some to have been deliberately artistic. At the University of South Florida, an engineering professor, through a grant with the National Science Foundation, has developed a course that connects art and engineering.
Among famous historical figures, Leonardo da Vinci is a well-known Renaissance artist and engineer, and a prime example of the nexus between art and engineering.
=== Business ===
Business engineering deals with the relationship between professional engineering, IT systems, business administration and change management. Engineering management or "Management engineering" is a specialized field of management concerned with engineering practice or the engineering industry sector. The demand for management-focused engineers (or from the opposite perspective, managers with an understanding of engineering), has resulted in the development of specialized engineering management degrees that develop the knowledge and skills needed for these roles. During an engineering management course, students will develop industrial engineering skills, knowledge, and expertise, alongside knowledge of business administration, management techniques, and strategic thinking. Engineers specializing in change management must have in-depth knowledge of the application of industrial and organizational psychology principles and methods. Professional engineers often train as certified management consultants in the very specialized field of management consulting applied to engineering practice or the engineering sector. This work often deals with large scale complex business transformation or business process management initiatives in aerospace and defence, automotive, oil and gas, machinery, pharmaceutical, food and beverage, electrical and electronics, power distribution and generation, utilities and transportation systems. This combination of technical engineering practice, management consulting practice, industry sector knowledge, and change management expertise enables professional engineers who are also qualified as management consultants to lead major business transformation initiatives. These initiatives are typically sponsored by C-level executives.
=== Other fields ===
In political science, the term engineering has been borrowed for the study of the subjects of social engineering and political engineering, which deal with forming political and social structures using engineering methodology coupled with political science principles. Marketing engineering and financial engineering have similarly borrowed the term.
== See also ==
Lists
Glossaries
Related subjects
== References ==
== Further reading ==
== External links ==
The dictionary definition of engineering at Wiktionary
Learning materials related to Engineering at Wikiversity
Quotations related to Engineering at Wikiquote
Works related to Engineering at Wikisource | Wikipedia/engineering |
Instrumentation and control engineering (ICE) is a branch of engineering that studies the measurement and control of process variables, and the design and implementation of systems that incorporate them. Process variables include pressure, temperature, humidity, flow, pH, force and speed.
ICE combines two branches of engineering. Instrumentation engineering is the science of the measurement and control of process variables within a production or manufacturing area. Meanwhile, control engineering, also called control systems engineering, is the engineering discipline that applies control theory to design systems with desired behaviors.
Control engineers are responsible for the research, design, and development of control devices and systems, typically in manufacturing facilities and process plants. Control methods employ sensors to measure the output variable of the device and provide feedback to the controller so that it can make corrections toward desired performance. Automatic control manages a device without the need of human inputs for correction, such as cruise control for regulating a car's speed.
Control systems engineering activities are multi-disciplinary in nature. They focus on the implementation of control systems, mainly derived by mathematical modeling. Because instrumentation and control play a significant role in gathering information from a system and changing its parameters, they are a key part of control loops.
== As profession ==
High demand for engineering professionals is found in fields associated with process automation. Specializations include industrial instrumentation, system dynamics, process control, and control systems. Additionally, technological knowledge, particularly in computer systems, is essential to the job of an instrumentation and control engineer; important technology-related topics include human–computer interaction, programmable logic controllers, and SCADA. The tasks center around designing, developing, maintaining and managing control systems.
The goals of the work of an instrumentation and control engineer are to maximize:
Productivity
Optimization
Stability
Reliability
Safety
Continuity
== As academic discipline ==
Instrumentation and control engineering is a vital field of study offered at many universities worldwide at both the graduate and postgraduate levels. This discipline integrates principles from various branches of engineering, providing a comprehensive understanding of the design, analysis, and management of automated systems.
Typical coursework for this discipline includes, but is not limited to, subjects such as control system design, instrumentation fundamentals, process control, sensors and signal processing, automation, robotics, and industrial data communications. Advanced courses may delve into topics like intelligent control systems, digital signal processing, and embedded systems design.
Students often have the opportunity to engage in hands-on laboratory work and industry-relevant projects, which foster practical skills alongside theoretical knowledge. These experiences are crucial in preparing graduates for careers in diverse sectors including manufacturing, power generation, oil and gas, and healthcare, where they may design and maintain systems that automate processes, improve efficiency, and enhance safety.
Interdisciplinary by nature, the field is accessible to students from various engineering backgrounds. Most commonly, students with a foundation in Electrical Engineering and Mechanical Engineering are drawn to this field due to their strong base in control systems, system dynamics, electro-mechanical machines and devices, and electric circuits (course work). However, with the growing complexity and integration of systems, students from fields like computer engineering, chemical engineering, and even biomedical engineering are increasingly contributing to and benefiting from studies in instrumentation and control engineering.
Furthermore, the rapid advancement of technology in areas like the Internet of Things (IoT), artificial intelligence (AI), and machine learning is continuously shaping the curriculum of this discipline, making it an ever-evolving and dynamic field of study.
== See also ==
Industrial system
Instrumentation in petrochemical industries
List of sensors
Metrology
Measurement
Programmable logic controller
International Society of Automation
== References ==
== External links ==
Industrial Instrumentation and Controls Technology Alliance
"Instrumentation and Control". | Wikipedia/Instrumentation_and_control |
In management it has been said that business transformation involves making fundamental changes in how business is conducted in order to help cope with shifts in market environment. However this is a relatively narrow definition that overlooks other reasons and ignores other rationales.
A better understanding is achieved by considering that "transformation [..] is generally a response to two things. First, there are underlying problems or causes of organisational pain that need to be addressed. They have to be properly understood but nevertheless they are a key component. Second, there is a desire by the top management and other senior stakeholders to use the opportunity of addressing these causes in ways that fundamentally alter the paradigm of the organisation." Others describe Business Transformation as "the process of fundamentally changing the systems, processes, people and technology across a whole business or business unit. As such, a business transformation project is likely to include any number of change management projects, each focused on an individual process, system, technology, team or department."
== When business transformation is used ==
The need for business transformation may be caused by external changes in the market such as an organisation's products or services being out of date, funding or income streams being changed, new regulations coming into force or market competition becoming more intense. This management approach may also incorporate business process reengineering (BPR). However application of BPR does not of itself constitute a business transformation, the outcome should be the deciding factor as to whether any activity is truly transformational or simply improvement. Other methods like Lean or Six Sigma are rooted in incremental improvement rather than paradigm shifts in the way things are done:
To increase revenue or market share
To improve customer satisfaction
To cut costs
== Components ==
Business transformation is achieved by one or more of: realigning the way staff work, how the organisation is structured, the core product or service portfolio of the business and how technology is used. Typically organizations go through several stages in transforming themselves:
Recognising the need to change and gaining consensus amongst stakeholders that change is necessary
Agreeing what form the change should take, the objectives of the change and a vision that describes a better future
Understanding what the organisation is changing from and what needs to change in detail
Designing the new organisational way of working and its support and management
Testing and implementing changes, usually in waves (this may take place over a number of years)
Bedding in the change so that the organisation cannot move back to how it was and achieves the intended benefits
Business transformation can lead to developing new competencies and making better use of existing competencies.
== Transformation examples ==
Examples of organisational transformation include:
General Motors' transformation and restructuring (around 2009)
BBC's Delivering Quality First programme (since 2011)
Box's pivot from consumer to enterprise (around 2009-2010)
British Airways' strategic transformation programme in response to low cost airlines (around 2004-2005)
== References == | Wikipedia/Business_transformation |
An engineering technologist is a professional trained in certain aspects of development and implementation of a respective area of technology. An education in engineering technology concentrates more on application and less on theory than does an engineering education. Engineering technologists often assist engineers; but after years of experience, they can also become engineers. Like engineers, areas where engineering technologists can work include product design, fabrication, and testing. Engineering technologists sometimes rise to senior management positions in industry or become entrepreneurs.
Engineering technologists are more likely than engineers to focus on post-development implementation, product manufacturing, or operation of technology. The American National Society of Professional Engineers (NSPE) makes the distinction that engineers are trained in conceptual skills, to "function as designers", while engineering technologists "apply others' designs". The mathematics and sciences, as well as other technical courses, in engineering technology programs, are taught with more application-based examples, whereas engineering coursework provides a more theoretical foundation in math and science. Moreover, engineering coursework tends to require higher-level mathematics including calculus and calculus-based theoretical science courses, as well as more extensive knowledge of the natural sciences, which serves to prepare students for research (whether in graduate studies or industrial R&D) as opposed to engineering technology coursework which focuses on algebra, trigonometry, applied calculus, and other courses that are more practical than theoretical in nature and generally have more labs that involve the hands-on application of the topics studied.
In the United States, although some states require, without exception, a BS degree in engineering at schools with programs accredited by the Engineering Accreditation Commission (EAC) of the Accreditation Board for Engineering and Technology (ABET), about two-thirds of the states accept BS degrees in engineering technology accredited by the Engineering Technology Accreditation Commission (ETAC) of the ABET, in order to become licensed as professional engineers. States have different requirements as to the years of experience needed to take the Fundamentals of Engineering (FE) and Professional Engineering (PE) exams. A few states require those sitting for the exams to have a master's degree in engineering. This education model is in line with the educational system in the United Kingdom where an accredited MEng or MSc degree in engineering is required by the Engineering Council (EngC) to be registered as a Chartered Engineer. Engineering technology graduates with can earn an MS degree in engineering technology, engineering, engineering management, construction management, or a National Architectural Accrediting Board (NAAB)-accredited Master of Architecture degree. These degrees are also offered online or through distance-learning programs at various universities, both nationally and internationally, which allows individuals to continue working full-time while earning an advanced degree.
== Nature of the work ==
Engineering technologists are more likely to work in testing, fabrication/construction or fieldwork, while engineers generally focus more on conceptual design and product development, with considerable overlap (e.g., testing and fabrication are often integral to the overall product development process and can involve engineers as well as engineering technologists).
Engineering technologists are employed in a wide array of industries and areas including product development, manufacturing and maintenance. They may become managers depending upon the experience and their educational emphasis on management. Entry-level positions relating in various ways to product design, product testing, product development, systems development, field engineering, technical operations, and quality control are common for engineering technologists. Most companies generally make no distinction between engineers and engineering technologists when it comes to hiring.
== Education and accreditation ==
Beginning in the 1950s and 1960s, some post-secondary institutions in the U.S. and Canada began offering degrees in engineering technology, focusing on applied study rather than the more theoretical studies required for engineering degrees. The focus on applied study addressed a need within the scientific, manufacturing, and engineering communities, as well as other industries, for professionals with hands-on and applications-based engineering knowledge. Depending on the institution, associate's or bachelor's degrees are offered, with some institutions also offering advanced degrees in engineering technology.
In general, an engineering technologist receives a broad range of applied science and applied mathematics training, as well as the fundamentals of engineering in the student's area of focus. Engineering technology programs typically include instruction in providing support to specific engineering specialties. Information technology is primarily involved with the management, operation, and maintenance of computer systems and networks, along with an application of technology in diverse fields such as architecture, engineering, graphic design, telecommunications, computer science, and network security. An engineering technologist is also expected to have had some coursework in ethics.
In 2001, Professional organizations from different countries have signed a mutual recognition agreement called the Sydney Accord, which represents an understanding that the academic credentials of engineering technologists will be recognized in all signatory states. The recognition given engineering technologists under the Sydney Accord can be compared to the Washington Accord for engineers and the Dublin Accord for engineering technicians. The Engineering Technologist Mobility Forum (ETMF) is an international forum held by signatories of the Sydney Accord to explore mutual recognition for experienced engineering technologists and to remove artificial barriers to the free movement and practice of engineering technologists amongst their countries. ETMF can be compared to the Engineers Mobility Forum (EMF) for engineers.
Graduates acquiring an associate degree, or lower, typically find careers as engineering technicians. According to the United States Bureau of Labor Statistics: "Many four-year colleges offer bachelor's degrees in engineering technology and graduates of these programs are hired to work as entry-level engineers or applied engineers, but not technicians." Engineering technicians typically have a two-year associate degree, while engineering technologists have a bachelor's degrees.
=== Canada ===
In Canada, the new occupational category of "technologist" was established in the 1960s, in conjunction with an emerging system of community colleges and technical institutes. It was designed to effectively bridge the gap between the increasingly theoretical nature of engineering degrees and the predominantly practical approach of technician and trades programs. Provincial associations may certify individuals as a professional technologist (P.Tech.), certified engineering technologist (C.E.T.), registered engineering technologist (R.E.T.), applied science technologist (AScT), or technologue professionel (T.P.). These provincial associations are constituent members of Technology Professionals Canada (TPC), which accredits technology programs across Canada, through its Technology Accreditation Canada (TAC). Nationally accredited engineering technology programs range from two to three years in length, depending on the province, and often require as many classroom hours as a 4-year degree program.
=== United States ===
In the United States, the U.S. Department of Education or the Council for Higher Education Accreditation (CHEA) are at the top of the educational accreditation hierarchy. The U.S. Department of Education acknowledges regional and national accreditation and CHEA recognizes specialty accreditation. One technology accreditation is currently recognized by CHEA: The Association of Technology, Management and Applied Engineering (ATMAE). CHEA recognizes ATMAE for accrediting associate, baccalaureate, and master's degree programs in technology, applied technology, engineering technology, and technology-related disciplines delivered by national or regional accredited institutions in the United States. As of March 2019, ABET withdrew from CHEA recognition
The National Institute for Certification in Engineering Technologies (NICET) awards certification at two levels, depending on work experience: the Associate Engineering Technologist (AT) and the Certified Engineering Technologist (CT). ATMAE awards two levels of certification in technology management: Certified Technology Manager (CTM) and Certified Senior Technology Manager (CSTM). ATMAE also awards two levels of certification of manufacturing specialist: Certified Manufacturing Specialist (CMS) and Certified Senior Manufacturing Specialist (CSMS). In 2020, ATMAE announced offering the Certified Controls Engineer (CCE) and Certified Senior Controls Engineer (CSCE) professional certifications. While the CTM, CMS, and CCE certifications are obtained through examination, the CSTM, CSMS and CSCE require industry experience and continuous improvement via the obtainment of professional development units (PDUs).
The American Society of Certified Engineering Technicians (ASCET) is a membership organization that issues Certified Member certifications to engineering technicians and engineering technologists. Professional engineers are issued Registered Member certification.
=== United Kingdom ===
The United Kingdom has a decades-long tradition of producing engineering technologists via the apprenticeship system. UK engineering technologists have always been designated as "engineers", which in the UK is used to describe the entire range of skilled workers and professionals, from tradespeople through to the highly educated Chartered Engineer. In fact up until the 1960s professional engineers in the UK were often referred to as "Technologists" to distinguish them from scientists, technicians, and craftsmen. The modern term for an engineering technologist is "incorporated engineer" (IEng), although since 2000 the normal route to achieving IEng is with a bachelor's or honors degree in engineering or technology. Modern technical apprenticeships would normally lead to the engineering technician (EngTech) professional qualification and, with further studies at higher apprenticeship level, an IEng. Since 2015, the Universities and Colleges Admissions Service (UCAS) has introduced engineering degree (bachelors and masters) apprenticeships. The title "incorporated engineer" is protected by civil law. Prior to the title "incorporated engineer", UK technologists were known as "technician engineers" a designation introduced in the 1960s.
In the United Kingdom, an incorporated engineer is accepted as a "professional engineer", registered by the EngC, although the term "professional engineer" has no legal meaning in the UK and there are no restrictions on the practice. In fact, anyone in the UK can call themselves an "engineer" or "professional engineer" without any qualifications or proven competence in engineering; and most UK skilled trades are sometimes referred to as "professional" or "accredited" engineers. Examples are "Registered Gas Engineer" (gas installer) or "Professional Telephone Engineer" (phone line installer or fault diagnosis).
Incorporated engineers are recognized internationally under the Sydney Accord as engineering technologists. One of the professional titles recognized by the Washington Accord for engineers in the United Kingdom is the chartered engineer. The incorporated engineer is a professional engineer as recognized by the EngC of the United Kingdom. The European designation, as demonstrated by the prescribed title under 2005/36/EC, is "engineer". The incorporated engineer operates autonomously and directs activities independently. They do not necessarily need the support of chartered engineers, because they are often acknowledged as full engineers in the UK (but not in Canada or the U.S.). The United Kingdom incorporated engineer may also contribute to the design of new products and systems.
The chartered engineer and incorporated engineer, whilst often undertaking similar roles, are distinct qualifications awarded by the EngC, with Chartered Engineer (CEng) status being the terminal engineering qualification.
Incorporated engineers currently require an IEng-accredited bachelors or honors degree in engineering (prior to 1997 the B.Sc. and B.Eng. degrees satisfied the academic requirements for "chartered engineer" registration), a Higher National Certificate or diploma, City and Guilds of London Institute higher diploma/full technological cert diploma, or a Foundation Degree in engineering, plus appropriate further learning to degree level, or an NVQ4 or SVQ4 qualifications approved for the purpose by a licensed engineering institution.
The academic requirements must be accompanied by the appropriate peer-reviewed experience in employment—typically 4 years post qualification. In addition to the experience and academic requirements, the engineering candidate must have three referees (themselves CEng or IEng) who vouch for the performance of the individual being considered for professional recognition. There are a number of alternative ways to achieve IEng status for those that do not have the necessary qualifications for applicants, but who can clearly show they have achieved the same level as those with qualifications, including:
writing a technical report, based upon their experience and demonstrate their knowledge and understanding of engineering principles;
earning the City and Guilds graduate diploma (bachelors level) and a postgraduate diploma (masters level) accredited by the Institution of Mechanical Engineers (IMechE), Institution of Engineering and Technology (IET) and Institution of Civil Engineers (ICE);
following a work-based learning program;
or taking an academic program specified by the institution to which they are applying.
=== Germany – European Union ===
==== Engineering technologist / state-certified engineer ====
The engineering technologist (state-certified technician; German: Staatlich geprüfter Techniker) are vocational (non-academic) qualifications at the tertiary level in Germany. The degree is governed by the framework agreement of trade and technical schools (resolution of the Standing Conference of the Ministers of Education and Cultural Affairs of the states in the Federal Republic of Germany of 7 November 2002 in its respective applicable version) and is recognised by all states of the Federal Republic of Germany. It is awarded after passing state examinations at state or state-recognised technical school or academies (German: Fachschule/Fachakademie). Through the Vocational Training Modernisation Act (12.12.2019), state-certified engineers are also allowed to hold the title Bachelor Professional in Technik as of 1 January 2020.
To be eligible for the engineering technologist examination, candidates must fulfill the following requirements: completion of one of the school systems (Hauptschule, Realschule, Gymnasium), an apprenticeship of at least two years duration, one year of completed professional work experience and attendance of an educational program with a course load of 2400–3000 hours, usually completed within two years, full-time, or 3.5–4 years, part-time, at vocational colleges.
==== State-certified technicians/engineers in the EU directives ====
As of 31 January 2012, state-certified engineers, state-certified business managers and state-certified designers are at level 6-bachelor in the European Qualifications Framework (EQF), equivalent to a bachelor's degree. As such, the engineering technologist constitutes an advanced entry qualification for German universities and in principle permits entry into any undergraduate academic-degree program.
The qualifications are listed in EU Directives as recognised, regulated professions in Germany and the EU. Annexes C and D were added to Council Directive 92/51/EEC as a second general system for the recognition of professional education and training to supplement Directive 89/48/EEC.
Institutions involved included the federal government (in Germany, the Federal Ministry of Education and Research and the Federal Ministry of Economics and Technology), EU Standing Conference and Economic Ministerial Meeting of Countries, the German Chamber of Crafts, the Confederation of German Employers' Associations, German Chambers of Industry and Commerce, Confederation of German Trade Unions, and the Federal Institute for Vocational Application. These government institutions agreed on a common position regarding the implementation of the EQF and a German qualifications framework (DQR).
European Union law and other documents considered to be public include:
Annexes C and D to Council Directive 92/51/EEC on a second general system for the recognition of professional education and training to supplement Directive 89/48/EEC
EU Directive 2005L0036-EN 01.01.2007
ANNEX III list of regulated education and training referred to in the third subparagraph of Article 13(2)
== See also ==
National Council of Examiners for Engineering and Surveying
American Society for Engineering Education
UNESCO-UNEVOC
Practical engineer
Drafter
== References ==
== Further reading ==
Sastry, M.K.S.; Clement K. Sankat; Harris Khan; Dave Bhajan (2008). "The need for technologists and applied technology programs: an experience from Trinidad and Tobago". International Journal of Management in Education. 2 (2): 222. doi:10.1504/IJMIE.2008.018393.
Sastry, M.K.S.; C.K. Sankat; D. Exall; K.D. Srivastava; H. Khan; B.Copeland; W. Lewis; D.Bhajan (April 2007). "An Appraisal of Tertiary Level Institutional Collaboration and Joint Degree Programs in Trinidad and Tobago". Latin American and Caribbean Journal of Engineering Education. 1 (1): 27–34. ISSN 1935-0295. Retrieved 4 October 2010. | Wikipedia/Incorporated_Engineer |
The open-design movement involves the development of physical products, machines and systems through use of publicly shared design information. This includes the making of both free and open-source software (FOSS) as well as open-source hardware. The process is generally facilitated by the Internet and often performed without monetary compensation. The goals and philosophy of the movement are identical to that of the open-source movement, but are implemented for the development of physical products rather than software. Open design is a form of co-creation, where the final product is designed by the users, rather than an external stakeholder such as a private company.
== Origin ==
Sharing of manufacturing information can be traced back to the 18th and 19th century. Aggressive patenting put an end to that period of extensive knowledge sharing.
More recently, principles of open design have been related to the free and open-source software movements. In 1997 Eric S. Raymond, Tim O'Reilly and Larry Augustin established "open source" as an alternative expression to "free software", and in 1997 Bruce Perens published The Open Source Definition. In late 1998, Dr. Sepehr Kiani (a PhD in mechanical engineering from MIT) realized that designers could benefit from open source policies, and in early 1999 he convinced Dr. Ryan Vallance and Dr. Samir Nayfeh of the potential benefits of open design in machine design applications. Together they established the Open Design Foundation (ODF) as a non-profit corporation, and set out to develop an Open Design Definition.
The idea of open design was taken up, either simultaneously or subsequently, by several other groups and individuals. The principles of open design are closely similar to those of open-source hardware design, which emerged in March 1998 when Reinoud Lamberts of the Delft University of Technology proposed on his "Open Design Circuits" website the creation of a hardware design community in the spirit of free software.
Ronen Kadushin coined the title "Open Design" in his 2004 Master's thesis, and the term was later formalized in the 2010 Open Design Manifesto.
== Current directions ==
The open-design movement currently unites two trends. On one hand, people apply their skills and time on projects for the common good, perhaps where funding or commercial interest is lacking, for developing countries or to help spread ecological or cheaper technologies. On the other hand, open design may provide a framework for developing advanced projects and technologies that might be beyond the resource of any single company or country and involve people who, without the copyleft mechanism, might not collaborate otherwise. There is now also a third trend, where these two methods come together to use high-tech open-source (e.g. 3D printing) but customized local solutions for sustainable development. Open Design holds great potential in driving future innovation as recent research has proven that stakeholder users working together produce more innovative designs than designers consulting users through more traditional means. The open-design movement may arguably organize production by prioritising socio-ecological well-being over corporate profits, over-production and excess consumption.
== Open machine design as compared to open-source software ==
The open-design movement is currently fairly nascent but holds great potential for the future. In some respects design and engineering are even more suited to open collaborative development than the increasingly common open-source software projects, because with 3D models and photographs the concept can often be understood visually. It is not even necessary that the project members speak the same languages to usefully collaborate.
However, there are certain barriers to overcome for open design when compared to software development where there are mature and widely used tools available and the duplication and distribution of code cost next to nothing. Creating, testing and modifying physical designs is not quite so straightforward because of the effort, time and cost required to create the physical artefact; although with access to emerging flexible computer-controlled manufacturing techniques the complexity and effort of construction can be significantly reduced (see tools mentioned in the fab lab article).
== Organizations ==
Open design was considered in 2012 a fledgling movement consisting of several unrelated or loosely related initiatives. Many of these organizations are single, funded projects, while a few organizations are focusing on an area needing development. In some cases (e.g. Thingiverse for 3D printable designs or Appropedia for open source appropriate technology) organizations are making an effort to create a centralized open source design repository as this enables innovation. Notable organizations include:
AguaClara, an open-source engineering group at Cornell University publishing a design tool and CAD designs for water treatment plants
Arduino, an open-source electronics hardware platform, community and company
Elektor
GrabCAD
Instructables
Local Motors: methods of transport, vehicles
LittleBits
One Laptop Per Child, a project to provide children in developing territories laptop computers with open hardware and software
OpenCores, digital electronic hardware
Open Architecture Network
Open Hardware and Design Alliance (OHANDA)
OpenStructures (OSP), a modular construction model where everyone designs on the basis of one shared geometrical grid.
Open Source Ecology, including solar cells
Thingiverse, miscellaneous
VOICED
VIA OpenBook netbook has CAD files for the design licensed under the Creative Commons Attribution Share Alike 3.0 Unported License
Wikispeed, open-source modular vehicles
Open Source Design, a community created in 2016 to hold space for designers interested in open source.
Zoetrope, an open design low-cost wind turbine.
== See also ==
3D printing services
Cosmopolitan localism
Commons-based peer production
Co-creation
Knowledge commons
Modular design
OpenBTS
Open manufacturing
Open-source appropriate technology
Open-source architecture
Open Source Initiative
Open-source software
Open standard and Open standardization
Open Design Alliance
Digital public goods
== References ==
== External links ==
Episodes of Collective Invention (Peter B. Meyer, August 2003) An article on several historical examples of what could be called "open design"
"Lawrence Lessig and the Creative Commons Developing Nations License" (Alex Steffen, November 2006) An interview with Lawrence Lessig on the use of the Developing Nations License by Architecture for Humanity to create a global open design network
"In the Next Industrial Revolution, Atoms Are the New Bits" (Chris Anderson, Wired February 2010) | Wikipedia/Open-design |
Biological systems engineering or biosystems engineering is a broad-based engineering discipline with particular emphasis on non-medical biology. It can be thought of as a subset of the broader notion of biological engineering or bio-technology though not in the respects that pertain to biomedical engineering as biosystems engineering tends to focus less on medical applications than on agriculture, ecosystems, and food science. The discipline focuses broadly on environmentally sound and sustainable engineering solutions to meet societies' ecologically related needs. Biosystems engineering integrates the expertise of fundamental engineering fields with expertise from non-engineering disciplines.
== Background and organization ==
Many college and university biological engineering departments have a history of being grounded in agricultural engineering and have only in the past two decades or so changed their names to reflect the movement towards more diverse biological based engineering programs. This major is sometimes called agricultural and biological engineering, biological and environmental engineering, etc., in different universities, generally reflecting interests of local employment opportunities.
Since biological engineering covers a wide spectrum, many departments now offer specialization options. Depending on the department and the specialization options offered within each program, curricula may overlap with other related fields. There are a number of different titles for BSE-related departments at various universities. The professional societies commonly associated with many Biological Engineering programs include the American Society of Agricultural and Biological Engineers (ASABE) and the Institute of Biological Engineering (IBE), which generally encompasses BSE. Some program also participate in the Biomedical Engineering Society (BMES) and the American Institute of Chemical Engineers (AIChE).
A biological systems engineer has a background in what both environmental engineers and biologists do, thus bridging the gap between engineering and the (non-medical) biological sciences – although this is variable across academic institutions. For this reason, biological systems engineers are becoming integral parts of many environmental engineering firms, federal agencies, and biotechnology industries. A biological systems engineer will often address the solution to a problem from the perspective of employing living systems to enact change. For example, biological treatment methodologies can be applied to provide access to clean drinking water or for sequestration of carbon dioxide.
== Specializations ==
Land and water resources engineering
Food engineering and bioprocess engineering
Machinery systems engineering
Natural resources and environmental engineering
Biomedical engineering
== Academic programs in agricultural and biological systems engineering ==
Below is a listing of known academic programs that offer bachelor's degrees (B.S. or B.S.E.) in what ABET and/or ASABE terms "agricultural engineering", "biological systems engineering", "biological engineering", or similarly named programs. ABET accredits college and university programs in the disciplines of applied science, computing, engineering, and engineering technology. ASABE defines accredited programs within the scope of Ag/Bio Engineering.
=== North America ===
=== Central and South America ===
=== Europe ===
=== Asia ===
=== Africa ===
== See also ==
== References ==
== Further reading ==
2003, Dennis R. Heldman (ed), Encyclopedia of agricultural, food, and biological engineering.
2002, Teruyuki Nagamune, Tai Hyun Park & Mark R. Marten (ed), Biological Systems Engineering, Washington, D.C. : American Chemical Society, 320 pages.
2012, Paige Brown Jarreau, What is Biological Engineering, http://www.scilogs.com/from_the_lab_bench/what-is-biological-engineering-ibe-2012/ Archived 2016-08-10 at the Wayback Machine
== External links ==
UC San Diego, Department of Bioengineering, UCSD BE part of University of California, San Diego | Wikipedia/Biosystems_engineering |
Electrical telegraphy is point-to-point distance communicating via sending electric signals over wire, a system primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems called telegraphs, that were devised to send text messages more quickly than physically carrying them. Electrical telegraphy can be considered the first example of electrical engineering.
Electrical telegraphy consisted of two or more geographically separated stations, called telegraph offices. The offices were connected by wires, usually supported overhead on utility poles. Many electrical telegraph systems were invented that operated in different ways, but the ones that became widespread fit into two broad categories. First are the needle telegraphs, in which electric current sent down the telegraph line produces electromagnetic force to move a needle-shaped pointer into position over a printed list. Early needle telegraph models used multiple needles, thus requiring multiple wires to be installed between stations. The first commercial needle telegraph system and the most widely used of its type was the Cooke and Wheatstone telegraph, invented in 1837. The second category are armature systems, in which the current activates a telegraph sounder that makes a click; communication on this type of system relies on sending clicks in coded rhythmic patterns. The archetype of this category was the Morse system and the code associated with it, both invented by Samuel Morse in 1838. In 1865, the Morse system became the standard for international communication, using a modified form of Morse's code that had been developed for German railways.
Electrical telegraphs were used by the emerging railway companies to provide signals for train control systems, minimizing the chances of trains colliding with each other. This was built around the signalling block system in which signal boxes along the line communicate with neighbouring boxes by telegraphic sounding of single-stroke bells and three-position needle telegraph instruments.
In the 1840s, the electrical telegraph superseded optical telegraph systems such as semaphores, becoming the standard way to send urgent messages. By the latter half of the century, most developed nations had commercial telegraph networks with local telegraph offices in most cities and towns, allowing the public to send messages (called telegrams) addressed to any person in the country, for a fee.
Beginning in 1850, submarine telegraph cables allowed for the first rapid communication between people on different continents. The telegraph's nearly-instant transmission of messages across continents – and between continents – had widespread social and economic impacts. The electric telegraph led to Guglielmo Marconi's invention of wireless telegraphy, the first means of radiowave telecommunication, which he began in 1894.
In the early 20th century, manual operation of telegraph machines was slowly replaced by teleprinter networks. Increasing use of the telephone pushed telegraphy into only a few specialist uses; its use by the general public dwindled to greetings for special occasions. The rise of the Internet and email in the 1990s largely made dedicated telegraphy networks obsolete.
== History ==
=== Precursors ===
Prior to the electric telegraph, visual systems were used, including beacons, smoke signals, flag semaphore, and optical telegraphs for visual signals to communicate over distances of land.
An auditory predecessor was West African talking drums. In the 19th century, Yoruba drummers used talking drums to mimic human tonal language to communicate complex messages – usually regarding news of birth, ceremonies, and military conflict – over 4–5 mile distances.
Possibly the earliest design and conceptualization for a telegraph system was by the British polymath Robert Hooke, who gave a vivid and comprehensive outline of visual telegraphy to the Royal Society in a 1684 submission in which he outlined many practical details. The system was largely motivated by military concerns, following the Battle of Vienna in 1683.
The first official optical telegraph was invented in France in the 18th century by Claude Chappe and his brothers. The Chappe system would stretch nearly 5,000 km with 556 stations and was used until the 1850s.
=== Early work ===
From early studies of electricity, electrical phenomena were known to travel with great speed, and many experimenters worked on the application of electricity to communications at a distance. All the known effects of electricity – such as sparks, electrostatic attraction, chemical changes, electric shocks, and later electromagnetism – were applied to the problems of detecting controlled transmissions of electricity at various distances.
In 1753, an anonymous writer in the Scots Magazine suggested an electrostatic telegraph. Using one wire for each letter of the alphabet, a message could be transmitted by connecting the wire terminals in turn to an electrostatic machine, and observing the deflection of pith balls at the far end. The writer has never been positively identified, but the letter was signed C.M. and posted from Renfrew leading to a Charles Marshall of Renfrew being suggested. Telegraphs employing electrostatic attraction were the basis of early experiments in electrical telegraphy in Europe, but were abandoned as being impractical and were never developed into a useful communication system.
In 1774, Georges-Louis Le Sage realised an early electric telegraph. The telegraph had a separate wire for each of the 26 letters of the alphabet and its range was only between two rooms of his home.
In 1800, Alessandro Volta invented the voltaic pile, providing a continuous current of electricity for experimentation. This became a source of a low-voltage current that could be used to produce more distinct effects, and which was far less limited than the momentary discharge of an electrostatic machine, which with Leyden jars were the only previously known human-made sources of electricity.
Another very early experiment in electrical telegraphy was an "electrochemical telegraph" created by the German physician, anatomist and inventor Samuel Thomas von Sömmering in 1809, based on an earlier 1804 design by Spanish polymath and scientist Francisco Salva Campillo. Both their designs employed multiple wires (up to 35) to represent almost all Latin letters and numerals. Thus, messages could be conveyed electrically up to a few kilometers (in von Sömmering's design), with each of the telegraph receiver's wires immersed in a separate glass tube of acid. An electric current was sequentially applied by the sender through the various wires representing each letter of a message; at the recipient's end, the currents electrolysed the acid in the tubes in sequence, releasing streams of hydrogen bubbles next to each associated letter or numeral. The telegraph receiver's operator would watch the bubbles and could then record the transmitted message. This is in contrast to later telegraphs that used a single wire (with ground return).
Hans Christian Ørsted discovered in 1820 that an electric current produces a magnetic field that will deflect a compass needle. In the same year Johann Schweigger invented the galvanometer, with a coil of wire around a compass, that could be used as a sensitive indicator for an electric current. Also that year, André-Marie Ampère suggested that telegraphy could be achieved by placing small magnets under the ends of a set of wires, one pair of wires for each letter of the alphabet. He was apparently unaware of Schweigger's invention at the time, which would have made his system much more sensitive. In 1825, Peter Barlow tried Ampère's idea but only got it to work over 200 feet (61 m) and declared it impractical. In 1830 William Ritchie improved on Ampère's design by placing the magnetic needles inside a coil of wire connected to each pair of conductors. He successfully demonstrated it, showing the feasibility of the electromagnetic telegraph, but only within a lecture hall.
In 1825, William Sturgeon invented the electromagnet, with a single winding of uninsulated wire on a piece of varnished iron, which increased the magnetic force produced by electric current. Joseph Henry improved it in 1828 by placing several windings of insulated wire around the bar, creating a much more powerful electromagnet which could operate a telegraph through the high resistance of long telegraph wires. During his tenure at The Albany Academy from 1826 to 1832, Henry first demonstrated the theory of the 'magnetic telegraph' by ringing a bell through one-mile (1.6 km) of wire strung around the room in 1831.
In 1835, Joseph Henry and Edward Davy independently invented the mercury dipping electrical relay, in which a magnetic needle is dipped into a pot of mercury when an electric current passes through the surrounding coil. In 1837, Davy invented the much more practical metallic make-and-break relay which became the relay of choice in telegraph systems and a key component for periodically renewing weak signals. Davy demonstrated his telegraph system in Regent's Park in 1837 and was granted a patent on 4 July 1838. Davy also invented a printing telegraph which used the electric current from the telegraph signal to mark a ribbon of calico infused with potassium iodide and calcium hypochlorite.
=== First working systems ===
The first working telegraph was built by the English inventor Francis Ronalds in 1816 and used static electricity. At the family home on Hammersmith Mall, he set up a complete subterranean system in a 175-yard (160 m) long trench as well as an eight-mile (13 km) long overhead telegraph. The lines were connected at both ends to revolving dials marked with the letters of the alphabet and electrical impulses sent along the wire were used to transmit messages. Offering his invention to the Admiralty in July 1816, it was rejected as "wholly unnecessary". His account of the scheme and the possibilities of rapid global communication in Descriptions of an Electrical Telegraph and of some other Electrical Apparatus was the first published work on electric telegraphy and even described the risk of signal retardation due to induction. Elements of Ronalds' design were utilised in the subsequent commercialisation of the telegraph over 20 years later.
The Schilling telegraph, invented by Baron Schilling von Canstatt in 1832, was an early needle telegraph. It had a transmitting device that consisted of a keyboard with 16 black-and-white keys. These served for switching the electric current. The receiving instrument consisted of six galvanometers with magnetic needles, suspended from silk threads. The two stations of Schilling's telegraph were connected by eight wires; six were connected with the galvanometers, one served for the return current and one for a signal bell. When at the starting station the operator pressed a key, the corresponding pointer was deflected at the receiving station. Different positions of black and white flags on different disks gave combinations which corresponded to the letters or numbers. Pavel Schilling subsequently improved its apparatus by reducing the number of connecting wires from eight to two.
On 21 October 1832, Schilling managed a short-distance transmission of signals between two telegraphs in different rooms of his apartment. In 1836, the British government attempted to buy the design but Schilling instead accepted overtures from Nicholas I of Russia. Schilling's telegraph was tested on a 5-kilometre-long (3.1 mi) experimental underground and underwater cable, laid around the building of the main Admiralty in Saint Petersburg and was approved for a telegraph between the imperial palace at Peterhof and the naval base at Kronstadt. However, the project was cancelled following Schilling's death in 1837. Schilling was also one of the first to put into practice the idea of the binary system of signal transmission. His work was taken over and developed by Moritz von Jacobi who invented telegraph equipment that was used by Tsar Alexander III to connect the Imperial palace at Tsarskoye Selo and Kronstadt Naval Base.
In 1833, Carl Friedrich Gauss, together with the physics professor Wilhelm Weber in Göttingen, installed a 1,200-metre-long (3,900 ft) wire above the town's roofs. Gauss combined the Poggendorff-Schweigger multiplicator with his magnetometer to build a more sensitive device, the galvanometer. To change the direction of the electric current, he constructed a commutator of his own. As a result, he was able to make the distant needle move in the direction set by the commutator on the other end of the line.
At first, Gauss and Weber used the telegraph to coordinate time, but soon they developed other signals and finally, their own alphabet. The alphabet was encoded in a binary code that was transmitted by positive or negative voltage pulses which were generated by means of moving an induction coil up and down over a permanent magnet and connecting the coil with the transmission wires by means of the commutator. The page of Gauss's laboratory notebook containing both his code and the first message transmitted, as well as a replica of the telegraph made in the 1850s under the instructions of Weber are kept in the faculty of physics at the University of Göttingen, in Germany.
Gauss was convinced that this communication would be of help to his kingdom's towns. Later in the same year, instead of a voltaic pile, Gauss used an induction pulse, enabling him to transmit seven letters a minute instead of two. The inventors and university did not have the funds to develop the telegraph on their own, but they received funding from Alexander von Humboldt. Carl August Steinheil in Munich was able to build a telegraph network within the city in 1835–1836. In 1838, Steinheil installed a telegraph along the Nuremberg–Fürth railway line, built in 1835 as the first German railroad, which was the first earth-return telegraph put into service.
By 1837, William Fothergill Cooke and Charles Wheatstone had co-developed a telegraph system which used a number of needles on a board that could be moved to point to letters of the alphabet. Any number of needles could be used, depending on the number of characters it was required to code. In May 1837 they patented their system. The patent recommended five needles, which coded twenty of the alphabet's 26 letters.
Samuel Morse independently developed and patented a recording electric telegraph in 1837. Morse's assistant Alfred Vail developed an instrument that was called the register for recording the received messages. It embossed dots and dashes on a moving paper tape by a stylus which was operated by an electromagnet. Morse and Vail developed the Morse code signalling alphabet.
On 24 May 1844, Morse sent to Vail the historic first message “WHAT HATH GOD WROUGHT" from the Capitol in Washington to the old Mt. Clare Depot in Baltimore.
== Commercial telegraphy ==
=== Cooke and Wheatstone system ===
The first commercial electrical telegraph was the Cooke and Wheatstone system. A demonstration four-needle system was installed on the Euston to Camden Town section of Robert Stephenson's London and Birmingham Railway in 1837 for signalling rope-hauling of locomotives. It was rejected in favour of pneumatic whistles. Cooke and Wheatstone had their first commercial success with a system installed on the Great Western Railway over the 13 miles (21 km) from Paddington station to West Drayton in 1838. This was a five-needle, six-wire system, and had the major advantage of displaying the letter being sent so operators did not need to learn a code. The insulation failed on the underground cables between Paddington and West Drayton, and when the line was extended to Slough in 1843, the system was converted to a one-needle, two-wire configuration with uninsulated wires on poles. The cost of installing wires was ultimately more economically significant than the cost of training operators. The one-needle telegraph proved highly successful on British railways, and 15,000 sets were in use at the end of the nineteenth century; some remained in service in the 1930s. The Electric Telegraph Company, the world's first public telegraphy company, was formed in 1845 by financier John Lewis Ricardo and Cooke.
=== Wheatstone ABC telegraph ===
Wheatstone developed a practical alphabetical system in 1840 called the A.B.C. System, used mostly on private wires. This consisted of a "communicator" at the sending end and an "indicator" at the receiving end. The communicator consisted of a circular dial with a pointer and the 26 letters of the alphabet (and four punctuation marks) around its circumference. Against each letter was a key that could be pressed. A transmission would begin with the pointers on the dials at both ends set to the start position. The transmitting operator would then press down the key corresponding to the letter to be transmitted. In the base of the communicator was a magneto actuated by a handle on the front. This would be turned to apply an alternating voltage to the line. Each half cycle of the current would advance the pointers at both ends by one position. When the pointer reached the position of the depressed key, it would stop and the magneto would be disconnected from the line. The communicator's pointer was geared to the magneto mechanism. The indicator's pointer was moved by a polarised electromagnet whose armature was coupled to it through an escapement. Thus the alternating line voltage moved the indicator's pointer on to the position of the depressed key on the communicator. Pressing another key would then release the pointer and the previous key, and re-connect the magneto to the line. These machines were very robust and simple to operate, and they stayed in use in Britain until well into the 20th century.
=== Morse system ===
The Morse system uses a single wire between offices. At the sending station, an operator taps on a switch called a telegraph key, spelling out text messages in Morse code. Originally, the armature was intended to make marks on paper tape, but operators learned to interpret the clicks and it was more efficient to write down the message directly.
In 1851, a conference in Vienna of countries in the German-Austrian Telegraph Union (which included many central European countries) adopted the Morse telegraph as the system for international communications. The international Morse code adopted was considerably modified from the original American Morse code, and was based on a code used on Hamburg railways (Gerke, 1848). A common code was a necessary step to allow direct telegraph connection between countries. With different codes, additional operators were required to translate and retransmit the message. In 1865, a conference in Paris adopted Gerke's code as the International Morse code and was henceforth the international standard. The US, however, continued to use American Morse code internally for some time, hence international messages required retransmission in both directions.
In the United States, the Morse/Vail telegraph was quickly deployed in the two decades following the first demonstration in 1844. The overland telegraph connected the west coast of the continent to the east coast by 24 October 1861, bringing an end to the Pony Express.
=== Foy–Breguet system ===
France was slow to adopt the electrical telegraph, because of the extensive optical telegraph system built during the Napoleonic era. There was also serious concern that an electrical telegraph could be quickly put out of action by enemy saboteurs, something that was much more difficult to do with optical telegraphs which had no exposed hardware between stations. The Foy-Breguet telegraph was eventually adopted. This was a two-needle system using two signal wires but displayed in a uniquely different way to other needle telegraphs. The needles made symbols similar to the Chappe optical system symbols, making it more familiar to the telegraph operators. The optical system was decommissioned starting in 1846, but not completely until 1855. In that year the Foy-Breguet system was replaced with the Morse system.
=== Expansion ===
As well as the rapid expansion of the use of the telegraphs along the railways, they soon spread into the field of mass communication with the instruments being installed in post offices. The era of mass personal communication had begun. Telegraph networks were expensive to build, but financing was readily available, especially from London bankers. By 1852, National systems were in operation in major countries:
The New York and Mississippi Valley Printing Telegraph Company, for example, was created in 1852 in Rochester, New York and eventually became the Western Union Telegraph Company. Although many countries had telegraph networks, there was no worldwide interconnection. Message by post was still the primary means of communication to countries outside Europe.
Telegraphy was introduced in Central Asia during the 1870s.
=== Telegraphic improvements ===
A continuing goal in telegraphy was to reduce the cost per message by reducing hand-work, or increasing the sending rate. There were many experiments with moving pointers, and various electrical encodings. However, most systems were too complicated and unreliable. A successful expedient to reduce the cost per message was the development of telegraphese.
The first system that did not require skilled technicians to operate was Charles Wheatstone's ABC system in 1840 in which the letters of the alphabet were arranged around a clock-face, and the signal caused a needle to indicate the letter. This early system required the receiver to be present in real time to record the message and it reached speeds of up to 15 words a minute.
In 1846, Alexander Bain patented a chemical telegraph in Edinburgh. The signal current moved an iron pen across a moving paper tape soaked in a mixture of ammonium nitrate and potassium ferrocyanide, decomposing the chemical and producing readable blue marks in Morse code. The speed of the printing telegraph was 16 and a half words per minute, but messages still required translation into English by live copyists. Chemical telegraphy came to an end in the US in 1851, when the Morse group defeated the Bain patent in the US District Court.
For a brief period, starting with the New York–Boston line in 1848, some telegraph networks began to employ sound operators, who were trained to understand Morse code aurally. Gradually, the use of sound operators eliminated the need for telegraph receivers to include register and tape. Instead, the receiving instrument was developed into a "sounder", an electromagnet that was energized by a current and attracted a small iron lever. When the sounding key was opened or closed, the sounder lever struck an anvil. The Morse operator distinguished a dot and a dash by the short or long interval between the two clicks. The message was then written out in long-hand.
Royal Earl House developed and patented a letter-printing telegraph system in 1846 which employed an alphabetic keyboard for the transmitter and automatically printed the letters on paper at the receiver, and followed this up with a steam-powered version in 1852. Advocates of printing telegraphy said it would eliminate Morse operators' errors. The House machine was used on four main American telegraph lines by 1852. The speed of the House machine was announced as 2600 words an hour.
David Edward Hughes invented the printing telegraph in 1855; it used a keyboard of 26 keys for the alphabet and a spinning type wheel that determined the letter being transmitted by the length of time that had elapsed since the previous transmission. The system allowed for automatic recording on the receiving end. The system was very stable and accurate and became accepted around the world.
The next improvement was the Baudot code of 1874. French engineer Émile Baudot patented a printing telegraph in which the signals were translated automatically into typographic characters. Each character was assigned a five-bit code, mechanically interpreted from the state of five on/off switches. Operators had to maintain a steady rhythm, and the usual speed of operation was 30 words per minute.
By this point, reception had been automated, but the speed and accuracy of the transmission were still limited to the skill of the human operator. The first practical automated system was patented by Charles Wheatstone. The message (in Morse code) was typed onto a piece of perforated tape using a keyboard-like device called the 'Stick Punch'. The transmitter automatically ran the tape through and transmitted the message at the then exceptionally high speed of 70 words per minute.
==== Teleprinters ====
An early successful teleprinter was invented by Frederick G. Creed. In Glasgow he created his first keyboard perforator, which used compressed air to punch the holes. He also created a reperforator (receiving perforator) and a printer. The reperforator punched incoming Morse signals onto paper tape and the printer decoded this tape to produce alphanumeric characters on plain paper. This was the origin of the Creed High Speed Automatic Printing System, which could run at an unprecedented 200 words per minute. His system was adopted by the Daily Mail for daily transmission of the newspaper contents.
With the invention of the teletypewriter, telegraphic encoding became fully automated. Early teletypewriters used the ITA-1 Baudot code, a five-bit code. This yielded only thirty-two codes, so it was over-defined into two "shifts", "letters" and "figures". An explicit, unshared shift code prefaced each set of letters and figures. In 1901, Baudot's code was modified by Donald Murray.
In the 1930s, teleprinters were produced by Teletype in the US, Creed in Britain and Siemens in Germany.
By 1935, message routing was the last great barrier to full automation. Large telegraphy providers began to develop systems that used telephone-like rotary dialling to connect teletypewriters. These resulting systems were called "Telex" (TELegraph EXchange). Telex machines first performed rotary-telephone-style pulse dialling for circuit switching, and then sent data by ITA2. This "type A" Telex routing functionally automated message routing.
The first wide-coverage Telex network was implemented in Germany during the 1930s as a network used to communicate within the government.
At the rate of 45.45 (±0.5%) baud – considered speedy at the time – up to 25 telex channels could share a single long-distance telephone channel by using voice frequency telegraphy multiplexing, making telex the least expensive method of reliable long-distance communication.
Automatic teleprinter exchange service was introduced into Canada by CPR Telegraphs and CN Telegraph in July 1957 and in 1958, Western Union started to build a Telex network in the United States.
==== The harmonic telegraph ====
The most expensive aspect of a telegraph system was the installation – the laying of the wire, which was often very long. The costs would be better covered by finding a way to send more than one message at a time through the single wire, thus increasing revenue per wire. Early devices included the duplex and the quadruplex which allowed, respectively, one or two telegraph transmissions in each direction. However, an even greater number of channels was desired on the busiest lines. In the latter half of the 1800s, several inventors worked towards creating a method for doing just that, including Charles Bourseul, Thomas Edison, Elisha Gray, and Alexander Graham Bell.
One approach was to have resonators of several different frequencies act as carriers of a modulated on-off signal. This was the harmonic telegraph, a form of frequency-division multiplexing. These various frequencies, referred to as harmonics, could then be combined into one complex signal and sent down the single wire. On the receiving end, the frequencies would be separated with a matching set of resonators.
With a set of frequencies being carried down a single wire, it was realized that the human voice itself could be transmitted electrically through the wire. This effort led to the invention of the telephone. (While the work toward packing multiple telegraph signals onto one wire led to telephony, later advances would pack multiple voice signals onto one wire by increasing the bandwidth by modulating frequencies much higher than human hearing. Eventually, the bandwidth was widened much further by using laser light signals sent through fiber optic cables. Fiber optic transmission can carry 25,000 telephone signals simultaneously down a single fiber.)
=== Oceanic telegraph cables ===
Soon after the first successful telegraph systems were operational, the possibility of transmitting messages across the sea by way of submarine communications cables was first proposed. One of the primary technical challenges was to sufficiently insulate the submarine cable to prevent the electric current from leaking out into the water. In 1842, a Scottish surgeon William Montgomerie introduced gutta-percha, the adhesive juice of the Palaquium gutta tree, to Europe. Michael Faraday and Wheatstone soon discovered the merits of gutta-percha as an insulator, and in 1845, the latter suggested that it should be employed to cover the wire which was proposed to be laid from Dover to Calais. Gutta-percha was used as insulation on a wire laid across the Rhine between Deutz and Cologne. In 1849, C. V. Walker, electrician to the South Eastern Railway, submerged a 2 miles (3.2 km) wire coated with gutta-percha off the coast from Folkestone, which was tested successfully.
John Watkins Brett, an engineer from Bristol, sought and obtained permission from Louis-Philippe in 1847 to establish telegraphic communication between France and England. The first undersea cable was laid in 1850, connecting the two countries and was followed by connections to Ireland and the Low Countries.
The Atlantic Telegraph Company was formed in London in 1856 to undertake to construct a commercial telegraph cable across the Atlantic Ocean. It was successfully completed on 18 July 1866 by the ship SS Great Eastern, captained by Sir James Anderson, after many mishaps along the way. John Pender, one of the men on the Great Eastern, later founded several telecommunications companies primarily laying cables between Britain and Southeast Asia. Earlier transatlantic submarine cables installations were attempted in 1857, 1858 and 1865. The 1857 cable only operated intermittently for a few days or weeks before it failed. The study of underwater telegraph cables accelerated interest in mathematical analysis of very long transmission lines. The telegraph lines from Britain to India were connected in 1870. (Those several companies combined to form the Eastern Telegraph Company in 1872.) The HMS Challenger expedition in 1873–1876 mapped the ocean floor for future underwater telegraph cables.
Australia was first linked to the rest of the world in October 1872 by a submarine telegraph cable at Darwin. This brought news reports from the rest of the world. The telegraph across the Pacific was completed in 1902, finally encircling the world.
From the 1850s until well into the 20th century, British submarine cable systems dominated the world system. This was set out as a formal strategic goal, which became known as the All Red Line. In 1896, there were thirty cable laying ships in the world and twenty-four of them were owned by British companies. In 1892, British companies owned and operated two-thirds of the world's cables and by 1923, their share was still 42.7 percent.
=== Cable and Wireless Company ===
Cable & Wireless was a British telecommunications company that traced its origins back to the 1860s, with Sir John Pender as the founder, although the name was only adopted in 1934. It was formed from successive mergers including:
The Falmouth, Malta, Gibraltar Telegraph Company
The British Indian Submarine Telegraph Company
The Marseilles, Algiers and Malta Telegraph Company
The Eastern Telegraph Company
The Eastern Extension Australasia and China Telegraph Company
The Eastern and Associated Telegraph Companies
== Telegraphy and longitude ==
Main article § Section: History of longitude § Land surveying and telegraphy.
The telegraph was very important for sending time signals to determine longitude, providing greater accuracy than previously available. Longitude was measured by comparing local time (for example local noon occurs when the sun is at its highest above the horizon) with absolute time (a time that is the same for an observer anywhere on earth). If the local times of two places differ by one hour, the difference in longitude between them is 15° (360°/24h). Before telegraphy, absolute time could be obtained from astronomical events, such as eclipses, occultations or lunar distances, or by transporting an accurate clock (a chronometer) from one location to the other.
The idea of using the telegraph to transmit a time signal for longitude determination was suggested by François Arago to Samuel Morse in 1837, and the first test of this idea was made by Capt. Wilkes of the U.S. Navy in 1844, over Morse's line between Washington and Baltimore. The method was soon in practical use for longitude determination, in particular by the U.S. Coast Survey, and over longer and longer distances as the telegraph network spread across North America and the world, and as technical developments improved accuracy and productivity: 318–330 : 98–107
The "telegraphic longitude net" soon became worldwide. Transatlantic links between Europe and North America were established in 1866 and 1870. The US Navy extended observations into the West Indies and Central and South America with an additional transatlantic link from South America to Lisbon between 1874 and 1890. British, Russian and US observations created a chain from Europe through Suez, Aden, Madras, Singapore, China and Japan, to Vladivostok, thence to Saint Petersburg and back to Western Europe.
Australia's telegraph network was linked to Singapore's via Java in 1871, and the net circled the globe in 1902 with the connection of the Australia and New Zealand networks to Canada's via the All Red Line. The two determinations of longitudes, one transmitted from east to west and the other from west to east, agreed within one second of arc (1⁄15 second of time – less than 30 metres).
== Telegraphy in war ==
The ability to send telegrams brought obvious advantages to those conducting war. Secret messages were encoded, so interception alone would not be sufficient for the opposing side to gain an advantage. There were also geographical constraints on intercepting the telegraph cables that improved security, however once radio telegraphy was developed interception became far more widespread.
=== Crimean War ===
The Crimean War was one of the first conflicts to use telegraphs and was one of the first to be documented extensively. In 1854, the government in London created a military Telegraph Detachment for the Army commanded by an officer of the Royal Engineers. It was to comprise twenty-five men from the Royal Corps of Sappers & Miners trained by the Electric Telegraph Company to construct and work the first field electric telegraph.
Journalistic recording of the war was provided by William Howard Russell (writing for The Times newspaper) with photographs by Roger Fenton. News from war correspondents kept the public of the nations involved in the war informed of the day-to-day events in a way that had not been possible in any previous war. After the French extended their telegraph lines to the coast of the Black Sea in late 1854, war news began reaching London in two days. When the British laid an underwater cable to the Crimean peninsula in April 1855, news reached London in a few hours. These prompt daily news reports energised British public opinion on the war, which brought down the government and led to Lord Palmerston becoming prime minister.
=== American Civil War ===
During the American Civil War the telegraph proved its value as a tactical, operational, and strategic communication medium and an important contributor to Union victory. By contrast the Confederacy failed to make effective use of the South's much smaller telegraph network. Prior to the War the telegraph systems were primarily used in the commercial sector. Government buildings were not inter-connected with telegraph lines, but relied on runners to carry messages back and forth. Before the war the Government saw no need to connect lines within city limits, however, they did see the use in connections between cities. Washington D.C. being the hub of government, it had the most connections, but there were only a few lines running north and south out of the city. It was not until the Civil War that the government saw the true potential of the telegraph system. Soon after the shelling of Fort Sumter, the South cut telegraph lines running into D.C., which put the city in a state of panic because they feared an immediate Southern invasion.
Within 6 months of the start of the war, the U.S. Military Telegraph Corps (USMT) had laid approximately 300 miles (480 km) of line. By war's end they had laid approximately 15,000 miles (24,000 km) of line, 8,000 for military and 5,000 for commercial use, and had handled approximately 6.5 million messages. The telegraph was not only important for communication within the armed forces, but also in the civilian sector, helping political leaders to maintain control over their districts.
Even before the war, the American Telegraph Company censored suspect messages informally to block aid to the secession movement. During the war, Secretary of War Simon Cameron, and later Edwin Stanton, wanted control over the telegraph lines to maintain the flow of information. Early in the war, one of Stanton's first acts as Secretary of War was to move telegraph lines from ending at McClellan's headquarters to terminating at the War Department. Stanton himself said "[telegraphy] is my right arm". Telegraphy assisted Northern victories, including the Battle of Antietam (1862), the Battle of Chickamauga (1863), and Sherman's March to the Sea (1864).
The telegraph system still had its flaws. The USMT, while the main source of telegraphers and cable, was still a civilian agency. Most operators were first hired by the telegraph companies and then contracted out to the War Department. This created tension between generals and their operators. One source of irritation was that USMT operators did not have to follow military authority. Usually they performed without hesitation, but they were not required to, so Albert Myer created a U.S. Army Signal Corps in February 1863. As the new head of the Signal Corps, Myer tried to get all telegraph and flag signaling under his command, and therefore subject to military discipline. After creating the Signal Corps, Myer pushed to further develop new telegraph systems. While the USMT relied primarily on civilian lines and operators, the Signal Corp's new field telegraph could be deployed and dismantled faster than USMT's system.
=== First World War ===
During World War I, Britain's telegraph communications were almost completely uninterrupted, while it was able to quickly cut Germany's cables worldwide. The British government censored telegraph cable companies in an effort to root out espionage and restrict financial transactions with Central Powers nations. British access to transatlantic cables and its codebreaking expertise led to the Zimmermann Telegram incident that contributed to the US joining the war. Despite British acquisition of German colonies and expansion into the Middle East, debt from the war led to Britain's control over telegraph cables to weaken while US control grew.
=== Second World War ===
World War II revived the 'cable war' of 1914–1918. In 1939, German-owned cables across the Atlantic were cut once again, and, in 1940, Italian cables to South America and Spain were cut in retaliation for Italian action against two of the five British cables linking Gibraltar and Malta. Electra House, Cable & Wireless's head office and central cable station, was damaged by German bombing in 1941.
Resistance movements in occupied Europe sabotaged communications facilities such as telegraph lines, forcing the Germans to use wireless telegraphy, which could then be intercepted by Britain.
The Germans developed a highly complex teleprinter attachment (German: Schlüssel-Zusatz, "cipher attachment") that was used for enciphering telegrams, using the Lorenz cipher, between German High Command (OKW) and the army groups in the field. These contained situation reports, battle plans, and discussions of strategy and tactics. Britain intercepted these signals, diagnosed how the encrypting machine worked, and decrypted a large amount of teleprinter traffic.
== End of the telegraph era ==
In America, the end of the telegraph era can be associated with the fall of the Western Union Telegraph Company. Western Union was the leading telegraph provider for America and was seen as the best competition for the National Bell Telephone Company. Western Union and Bell were both invested in telegraphy and telephone technology. Western Union's decision to allow Bell to gain the advantage in telephone technology was the result of Western Union's upper management's failure to foresee the surpassing of the telephone over the, at the time, dominant telegraph system. Western Union soon lost the legal battle for the rights to their telephone copyrights. This led to Western Union agreeing to a lesser position in the telephone competition, which in turn led to the lessening of the telegraph.
While the telegraph was not the focus of the legal battles that occurred around 1878, the companies that were affected by the effects of the battle were the main powers of telegraphy at the time. Western Union thought that the agreement of 1878 would solidify telegraphy as the long-range communication of choice. However, due to the underestimates of telegraph's future and poor contracts, Western Union found itself declining. AT&T acquired working control of Western Union in 1909 but relinquished it in 1914 under threat of antitrust action. AT&T bought Western Union's electronic mail and Telex businesses in 1990.
Although commercial "telegraph" services are still available in many countries, transmission is usually done via a computer network rather than a dedicated wired connection.
== See also ==
== References ==
== Bibliography ==
Beauchamp, Ken (2001). History of Telegraphy. London: The Institution of Electrical Engineers. ISBN 978-0-85296-792-8.
Bowers, Brian, Sir Charles Wheatstone: 1802–1875, IET, 2001 ISBN 0852961030
Calvert, J. B. (2008). "The Electromagnetic Telegraph".
Copeland, B. Jack, ed. (2006). Colossus: The Secrets of Bletchley Park's Codebreaking Computers. Oxford: Oxford University Press. ISBN 978-0-19-284055-4.
Fahie, John Joseph (1884). A History of Electric Telegraphy, to the Year 1837. London: E. & F.N. Spon. OCLC 559318239.
Figes, Orlando (2010). Crimea: The Last Crusade. London: Allen Lane. ISBN 978-0-7139-9704-0.
Gibberd, William (1966). Australian Dictionary of Biography: Edward Davy.
Hochfelder, David (2012). The Telegraph in America, 1832–1920. Johns Hopkins University Press. pp. 6–17, 138–141. ISBN 9781421407470.
Holzmann, Gerard J.; Pehrson, Björn, The Early History of Data Networks, Wiley, 1995 ISBN 0818667826
Huurdeman, Anton A. (2003). The Worldwide History of Telecommunications. Wiley-Blackwell. ISBN 978-0471205050.
Jones, R. Victor (1999). Samuel Thomas von Sömmering's "Space Multiplexed" Electrochemical Telegraph (1808–1810). Archived from the original on 11 October 2012. Retrieved 1 May 2009. Attributed to Michaelis, Anthony R. (1965), From semaphore to satellite, Geneva: International Telecommunication Union
Kennedy, P. M. (October 1971). "Imperial Cable Communications and Strategy, 1870–1914". The English Historical Review. 86 (341): 728–752. doi:10.1093/ehr/lxxxvi.cccxli.728. JSTOR 563928.
Kieve, Jeffrey L. (1973). The Electric Telegraph: A Social and Economic History. David and Charles. ISBN 0-7153-5883-9. OCLC 655205099.
Mercer, David, The Telephone: The Life Story of a Technology, Greenwood Publishing Group, 2006 ISBN 031333207X
Schwoch, James (2018). Wired into Nature: The Telegraph and the North American Frontier. University of Illinois Press. ISBN 978-0252041778.
== Further reading ==
Botjer, George F. (2015). Samuel F.B. Morse and the Dawn of the Age of Electricity. Lanham, MD: Lexington Books. ISBN 978-1-4985-0140-8 – via Internet Archive.
Cooke, W.F., The Electric Telegraph, Was it invented by Prof. Wheatstone?, London 1856.
Gray, Thomas (1892). "The Inventors of the Telegraph And Telephone". Annual Report of the Board of Regents of the Smithsonian Institution. 71: 639–659. Retrieved 7 August 2009.
Gauß, C. F., Works, Göttingen 1863–1933.
Howe, Daniel Walker, What Hath God Wrought: The Transformation of America, 1815–1848, Oxford University Press, 2007 ISBN 0199743797.
Peterson, M.J. Roots of Interconnection: Communications, Transportation and Phases of the Industrial Revolution, International Dimensions of Ethics Education in Science and Engineering Background Reading, Version 1; February 2008.
Steinheil, C.A., Ueber Telegraphie, München 1838.
Yates, JoAnne. The Telegraph's Effect on Nineteenth Century Markets and Firms, Massachusetts Institute of Technology, pp. 149–163.
== External links ==
Morse Telegraph Club, Inc. (The Morse Telegraph Club is an international non-profit organization dedicated to the perpetuation of the knowledge and traditions of telegraphy.)
"Transatlantic Cable Communications". Canada's Digital Collections. Archived from the original on 29 August 2005.
Shilling's telegraph, an exhibit of the A.S. Popov Central Museum of Communications
History of electromagnetic telegraph
The first electric telegraphs
The Dawn of Telegraphy (in Russian)
Pavel Shilling and his telegraph- article in PCWeek, Russian edition.
Distant Writing – The History of the Telegraph Companies in Britain between 1838 and 1868
NASA – Carrington Super Flare Archived 29 March 2010 at the Wayback Machine NASA 6 May 2008
How Cables Unite The World – a 1902 article about telegraph networks and technology from the magazine The World's Work
"Telegraph" . New International Encyclopedia. 1905.
Indiana telegraph and telephone collection, Rare Books and Manuscripts, Indiana State Library
Wonders of electricity and the elements, being a popular account of modern electrical and magnetic discoveries, magnetism and electric machines, the electric telegraph and the electric light, and the metal bases, salt, and acids from Science History Institute Digital Collections
The electro magnetic telegraph: with an historical account of its rise, progress, and present condition from Science History Institute Digital Collections | Wikipedia/Electric_telegraph |
Structural engineering is a sub-discipline of civil engineering in which structural engineers are trained to design the 'bones and joints' that create the form and shape of human-made structures. Structural engineers also must understand and calculate the stability, strength, rigidity and earthquake-susceptibility of built structures for buildings and nonbuilding structures. The structural designs are integrated with those of other designers such as architects and building services engineer and often supervise the construction of projects by contractors on site. They can also be involved in the design of machinery, medical equipment, and vehicles where structural integrity affects functioning and safety. See glossary of structural engineering.
Structural engineering theory is based upon applied physical laws and empirical knowledge of the structural performance of different materials and geometries. Structural engineering design uses a number of relatively simple structural concepts to build complex structural systems. Structural engineers are responsible for making creative and efficient use of funds, structural elements and materials to achieve these goals.
== History ==
Structural engineering dates back to 2700 B.C. when the step pyramid for Pharaoh Djoser was built by Imhotep, the first engineer in history known by name. Pyramids were the most common major structures built by ancient civilizations because the structural form of a pyramid is inherently stable and can be almost infinitely scaled (as opposed to most other structural forms, which cannot be linearly increased in size in proportion to increased loads).
The structural stability of the pyramid, whilst primarily gained from its shape, relies also on the strength of the stone from which it is constructed, and its ability to support the weight of the stone above it. The limestone blocks were often taken from a quarry near the building site and have a compressive strength from 30 to 250 MPa (MPa = Pa × 106). Therefore, the structural strength of the pyramid stems from the material properties of the stones from which it was built rather than the pyramid's geometry.
Throughout ancient and medieval history most architectural design and construction were carried out by artisans, such as stonemasons and carpenters, rising to the role of master builder. No theory of structures existed, and understanding of how structures stood up was extremely limited, and based almost entirely on empirical evidence of 'what had worked before' and intuition. Knowledge was retained by guilds and seldom supplanted by advances. Structures were repetitive, and increases in scale were incremental.
No record exists of the first calculations of the strength of structural members or the behavior of structural material, but the profession of a structural engineer only really took shape with the Industrial Revolution and the re-invention of concrete (see History of Concrete). The physical sciences underlying structural engineering began to be understood in the Renaissance and have since developed into computer-based applications pioneered in the 1970s.
=== Timeline ===
1452–1519 Leonardo da Vinci made many contributions.
1638: Galileo Galilei published the book Two New Sciences in which he examined the failure of simple structures.
1660: Hooke's law by Robert Hooke.
1687: Isaac Newton published Philosophiæ Naturalis Principia Mathematica, which contains his laws of motion.
1750: Euler–Bernoulli beam equation.
1700–1782: Daniel Bernoulli introduced the principle of virtual work.
1707–1783: Leonhard Euler developed the theory of buckling of columns.
1826: Claude-Louis Navier published a treatise on the elastic behaviors of structures.
1873: Carlo Alberto Castigliano presented his dissertation "Intorno ai sistemi elastici", which contains his theorem for computing displacement as the partial derivative of the strain energy. This theorem includes the method of "least work" as a special case.
1874: Otto Mohr formalized the idea of a statically indeterminate structure.
1922: Timoshenko corrects the Euler–Bernoulli beam equation.
1936: Hardy Cross' publication of the moment distribution method, an important innovation in the design of continuous frames.
1941: Alexander Hrennikoff solved the discretization of plane elasticity problems using a lattice framework.
1942: Richard Courant divided a domain into finite subregions.
1956: J. Turner, R. W. Clough, H. C. Martin, and L. J. Topp's paper on the "Stiffness and Deflection of Complex Structures" introduces the name "finite-element method" and is widely recognized as the first comprehensive treatment of the method as it is known today.
=== Structural failure ===
The history of structural engineering contains many collapses and failures. Sometimes this is due to obvious negligence, as in the case of the Pétion-Ville school collapse, in which Rev. Fortin Augustin " constructed the building all by himself, saying he didn't need an engineer as he had good knowledge of construction" following a partial collapse of the three-story schoolhouse that sent neighbors fleeing. The final collapse killed 94 people, mostly children.
In other cases structural failures require careful study, and the results of these inquiries have resulted in improved practices and a greater understanding of the science of structural engineering. Some such studies are the result of forensic engineering investigations where the original engineer seems to have done everything in accordance with the state of the profession and acceptable practice yet a failure still eventuated. A famous case of structural knowledge and practice being advanced in this manner can be found in a series of failures involving box girders which collapsed in Australia during the 1970s.
== Theory ==
Structural engineering depends upon a detailed knowledge of applied mechanics, materials science, and applied mathematics to understand and predict how structures support and resist self-weight and imposed loads. To apply the knowledge successfully a structural engineer generally requires detailed knowledge of relevant empirical and theoretical design codes, the techniques of structural analysis, as well as some knowledge of the corrosion resistance of the materials and structures, especially when those structures are exposed to the external environment. Since the 1990s, specialist software has become available to aid in the design of structures, with the functionality to assist in the drawing, analyzing and designing of structures with maximum precision; examples include AutoCAD, StaadPro, ETABS, Prokon, Revit Structure, Inducta RCB, etc. Such software may also take into consideration environmental loads, such as earthquakes and winds.
== Profession ==
Structural engineers are responsible for engineering design and structural analysis. Entry-level structural engineers may design the individual structural elements of a structure, such as the beams and columns of a building. More experienced engineers may be responsible for the structural design and integrity of an entire system, such as a building.
Structural engineers often specialize in particular types of structures, such as buildings, bridges, pipelines, industrial, tunnels, vehicles, ships, aircraft, and spacecraft. Structural engineers who specialize in buildings may specialize in particular construction materials such as concrete, steel, wood, masonry, alloys and composites.
Structural engineering has existed since humans first started to construct their structures. It became a more defined and formalized profession with the emergence of architecture as a distinct profession from engineering during the industrial revolution in the late 19th century. Until then, the architect and the structural engineer were usually one and the same thing – the master builder. Only with the development of specialized knowledge of structural theories that emerged during the 19th and early 20th centuries, did the professional structural engineers come into existence.
The role of a structural engineer today involves a significant understanding of both static and dynamic loading and the structures that are available to resist them. The complexity of modern structures often requires a great deal of creativity from the engineer in order to ensure the structures support and resist the loads they are subjected to. A structural engineer will typically have a four or five-year undergraduate degree, followed by a minimum of three years of professional practice before being considered fully qualified.
Structural engineers are licensed or accredited by different learned societies and regulatory bodies around the world (for example, the Institution of Structural Engineers in the UK). Depending on the degree course they have studied and/or the jurisdiction they are seeking licensure in, they may be accredited (or licensed) as just structural engineers, or as civil engineers, or as both civil and structural engineers.
Another international organisation is IABSE(International Association for Bridge and Structural Engineering). The aim of that association is to exchange knowledge and to advance the practice of structural engineering worldwide in the service of the profession and society.
== Specializations ==
=== Building structures ===
Structural building engineering is primarily driven by the creative manipulation of materials and forms and the underlying mathematical and scientific ideas to achieve an end that fulfills its functional requirements and is structurally safe when subjected to all the loads it could reasonably be expected to experience. This is subtly different from architectural design, which is driven by the creative manipulation of materials and forms, mass, space, volume, texture, and light to achieve an end which is aesthetic, functional, and often artistic.
The structural design for a building must ensure that the building can stand up safely, able to function without excessive deflections or movements which may cause fatigue of structural elements, cracking or failure of fixtures, fittings or partitions, or discomfort for occupants. It must account for movements and forces due to temperature, creep, cracking, and imposed loads. It must also ensure that the design is practically buildable within acceptable manufacturing tolerances of the materials. It must allow the architecture to work, and the building services to fit within the building and function (air conditioning, ventilation, smoke extract, electrics, lighting, etc.). The structural design of a modern building can be extremely complex and often requires a large team to complete.
Structural engineering specialties for buildings include:
Earthquake engineering
Façade engineering
Fire engineering
Roof engineering
Tower engineering
Wind engineering
=== Earthquake engineering structures ===
Earthquake engineering structures are those engineered to withstand earthquakes.
The main objectives of earthquake engineering are to understand the interaction of structures with the shaking ground, foresee the consequences of possible earthquakes, and design and construct the structures to perform during an earthquake.
Earthquake-proof structures are not necessarily extremely strong like the El Castillo pyramid at Chichen Itza shown above.
One important tool of earthquake engineering is base isolation, which allows the base of a structure to move freely with the ground.
=== Civil engineering structures ===
Civil structural engineering includes all structural engineering related to the built environment. It includes:
The structural engineer is the lead designer on these structures, and often the sole designer. In the design of structures such as these, structural safety is of paramount importance (in the UK, designs for dams, nuclear power stations and bridges must be signed off by a chartered engineer).
Civil engineering structures are often subjected to very extreme forces, such as large variations in temperature, dynamic loads such as waves or traffic, or high pressures from water or compressed gases. They are also often constructed in corrosive environments, such as at sea, in industrial facilities, or below ground.
resisted and significant deflections of structures.
The forces which parts of a machine are subjected to can vary significantly and can do so at a great rate. The forces which a boat or aircraft are subjected to vary enormously and will do so thousands of times over the structure's lifetime. The structural design must ensure that such structures can endure such loading for their entire design life without failing.
These works can require mechanical structural engineering:
Boilers and pressure vessels
Coachworks and carriages
Cranes
Elevators
Escalators
Marine vessels and hulls
=== Aerospace structures ===
Aerospace structure types include launch vehicles, (Atlas, Delta, Titan), missiles (ALCM, Harpoon), Hypersonic vehicles (Space Shuttle), military aircraft (F-16, F-18) and commercial aircraft (Boeing 777, MD-11). Aerospace structures typically consist of thin plates with stiffeners for the external surfaces, bulkheads, and frames to support the shape and fasteners such as welds, rivets, screws, and bolts to hold the components together.
=== Nanoscale structures ===
A nanostructure is an object of intermediate size between molecular and microscopic (micrometer-sized) structures. In describing nanostructures it is necessary to differentiate between the number of dimensions on the nanoscale. Nanotextured surfaces have one dimension on the nanoscale, i.e., only the thickness of the surface of an object is between 0.1 and 100 nm. Nanotubes have two dimensions on the nanoscale, i.e., the diameter of the tube is between 0.1 and 100 nm; its length could be much greater. Finally, spherical nanoparticles have three dimensions on the nanoscale, i.e., the particle is between 0.1 and 100 nm in each spatial dimension. The terms nanoparticles and ultrafine particles (UFP) often are used synonymously although UFP can reach into the micrometer range. The term 'nanostructure' is often used when referring to magnetic technology.
=== Structural engineering for medical science ===
Medical equipment (also known as armamentarium) is designed to aid in the diagnosis, monitoring or treatment of medical conditions. There are several basic types: diagnostic equipment includes medical imaging machines, used to aid in diagnosis; equipment includes infusion pumps, medical lasers, and LASIK surgical machines; medical monitors allow medical staff to measure a patient's medical state. Monitors may measure patient vital signs and other parameters including ECG, EEG, blood pressure, and dissolved gases in the blood; diagnostic medical equipment may also be used in the home for certain purposes, e.g. for the control of diabetes mellitus. A biomedical equipment technician (BMET) is a vital component of the healthcare delivery system. Employed primarily by hospitals, BMETs are the people responsible for maintaining a facility's medical equipment.
== Structural elements ==
Any structure is essentially made up of only a small number of different types of elements:
Columns
Beams
Plates
Arches
Shells
Catenaries
Many of these elements can be classified according to form (straight, plane / curve) and dimensionality (one-dimensional / two-dimensional):
=== Columns ===
Columns are elements that carry only axial force (compression) or both axial force and bending (which is technically called a beam-column but practically, just a column). The design of a column must check the axial capacity of the element and the buckling capacity.
The buckling capacity is the capacity of the element to withstand the propensity to buckle. Its capacity depends upon its geometry, material, and the effective length of the column, which depends upon the restraint conditions at the top and bottom of the column. The effective length is
K
∗
l
{\displaystyle K*l}
where
l
{\displaystyle l}
is the real length of the column and K is the factor dependent on the restraint conditions.
The capacity of a column to carry axial load depends on the degree of bending it is subjected to, and vice versa. This is represented on an interaction chart and is a complex non-linear relationship.
=== Beams ===
A beam may be defined as an element in which one dimension is much greater than the other two and the applied loads are usually normal to the main axis of the element. Beams and columns are called line elements and are often represented by simple lines in structural modeling.
cantilevered (supported at one end only with a fixed connection)
simply supported (fixed against vertical translation at each end and horizontal translation at one end only, and able to rotate at the supports)
fixed (supported in all directions for translation and rotation at each end)
continuous (supported by three or more supports)
a combination of the above (ex. supported at one end and in the middle)
Beams are elements that carry pure bending only. Bending causes one part of the section of a beam (divided along its length) to go into compression and the other part into tension. The compression part must be designed to resist buckling and crushing, while the tension part must be able to adequately resist the tension.
=== Trusses ===
A truss is a structure comprising members and connection points or nodes. When members are connected at nodes and forces are applied at nodes members can act in tension or compression. Members acting in compression are referred to as compression members or struts while members acting in tension are referred to as tension members or ties. Most trusses use gusset plates to connect intersecting elements. Gusset plates are relatively flexible and unable to transfer bending moments. The connection is usually arranged so that the lines of force in the members are coincident at the joint thus allowing the truss members to act in pure tension or compression.
Trusses are usually used in large-span structures, where it would be uneconomical to use solid beams.
=== Plates ===
Plates carry bending in two directions. A concrete flat slab is an example of a plate. Plate behavior is based on continuum mechanics. Due to the complexity involved they are most often analyzed using a finite element analysis.
They can also be designed with yield line theory, where an assumed collapse mechanism is analyzed to give an upper bound on the collapse load. This technique is used in practice but because the method provides an upper-bound (i.e. an unsafe prediction of the collapse load) for poorly conceived collapse mechanisms, great care is needed to ensure that the assumed collapse mechanism is realistic.
=== Shells ===
Shells derive their strength from their form and carry forces in compression in two directions. A dome is an example of a shell. They can be designed by making a hanging-chain model, which will act as a catenary in pure tension and inverting the form to achieve pure compression.
=== Arches ===
Arches carry forces in compression in one direction only, which is why it is appropriate to build arches out of masonry. They are designed by ensuring that the line of thrust of the force remains within the depth of the arch. It is mainly used to increase the bountifulness of any structure.
=== Catenaries ===
Catenaries derive their strength from their form and carry transverse forces in pure tension by deflecting (just as a tightrope will sag when someone walks on it). They are almost always cable or fabric structures. A fabric structure acts as a catenary in two directions.
== Materials ==
Structural engineering depends on the knowledge of materials and their properties, in order to understand how different materials support and resist loads. It also involves a knowledge of Corrosion engineering to avoid for example galvanic coupling of dissimilar materials.
Common structural materials are:
Iron: wrought iron, cast iron
Concrete: reinforced concrete, prestressed concrete
Alloy: steel, stainless steel
Masonry
Timber: hardwood, softwood
Aluminium
Composite materials: plywood
Other structural materials: adobe, bamboo, carbon fibre, fiber reinforced plastic, mudbrick, roofing materials
== See also ==
== Notes ==
== References ==
Hibbeler, R. C. (2010). Structural Analysis. Prentice-Hall.
Blank, Alan; McEvoy, Michael; Plank, Roger (1993). Architecture and Construction in Steel. Taylor & Francis. ISBN 0-419-17660-8.
Hewson, Nigel R. (2003). Prestressed Concrete Bridges: Design and Construction. Thomas Telford. ISBN 0-7277-2774-5.
Heyman, Jacques (1999). The Science of Structural Engineering. Imperial College Press. ISBN 1-86094-189-3.
Hosford, William F. (2005). Mechanical Behavior of Materials. Cambridge University Press. ISBN 0-521-84670-6.
== Further reading ==
Blockley, David (2014). A Very Short Introduction to Structural Engineering. Oxford University Press ISBN 978-0-19967193-9.
Bradley, Robert E.; Sandifer, Charles Edward (2007). Leonhard Euler: Life, Work, and Legacy. Elsevier. ISBN 0-444-52728-1.
Chapman, Allan. (2005). England's Leornardo: Robert Hooke and the Seventeenth Century's Scientific Revolution. CRC Press. ISBN 0-7503-0987-3.
Dugas, René (1988). A History of Mechanics. Courier Dover Publications. ISBN 0-486-65632-2.
Feld, Jacob; Carper, Kenneth L. (1997). Construction Failure. John Wiley & Sons. ISBN 0-471-57477-5.
Galilei, Galileo. (translators: Crew, Henry; de Salvio, Alfonso) (1954). Dialogues Concerning Two New Sciences. Courier Dover Publications. ISBN 0-486-60099-8
Kirby, Richard Shelton (1990). Engineering in History. Courier Dover Publications. ISBN 0-486-26412-2.
Heyman, Jacques (1998). Structural Analysis: A Historical Approach. Cambridge University Press. ISBN 0-521-62249-2.
Labrum, E.A. (1994). Civil Engineering Heritage. Thomas Telford. ISBN 0-7277-1970-X.
Lewis, Peter R. (2004). Beautiful Bridge of the Silvery Tay. Tempus.
Mir, Ali (2001). Art of the Skyscraper: the Genius of Fazlur Khan. Rizzoli International Publications. ISBN 0-8478-2370-9.
Rozhanskaya, Mariam; Levinova, I. S. (1996). "Statics" in Morelon, Régis & Rashed, Roshdi (1996). Encyclopedia of the History of Arabic Science, vol. 2–3, Routledge. ISBN 0-415-02063-8
Whitbeck, Caroline (1998). Ethics in Engineering Practice and Research. Cambridge University Press. ISBN 0-521-47944-4.
Hoogenboom P.C.J. (1998). "Discrete Elements and Nonlinearity in Design of Structural Concrete Walls", Section 1.3 Historical Overview of Structural Concrete Modelling, ISBN 90-901184-3-8.
Nedwell, P.J.; Swamy, R.N.(ed) (1994). Ferrocement:Proceedings of the Fifth International Symposium. Taylor & Francis. ISBN 0-419-19700-1.
== External links ==
Structural Engineering Association – International
National Council of Structural Engineers Associations
Structural Engineering Institute, an institute of the American Society of Civil Engineers
Structurae database of structures
Structural Engineering Association – International
The EN Eurocodes are a series of 10 European Standards, EN 1990 – EN 1999, providing a common approach for the design of buildings and other civil engineering works and construction products | Wikipedia/Structural_design |
Tension is the pulling or stretching force transmitted axially along an object such as a string, rope, chain, rod, truss member, or other object, so as to stretch or pull apart the object. In terms of force, it is the opposite of compression. Tension might also be described as the action-reaction pair of forces acting at each end of an object.
At the atomic level, when atoms or molecules are pulled apart from each other and gain potential energy with a restoring force still existing, the restoring force might create what is also called tension. Each end of a string or rod under such tension could pull on the object it is attached to, in order to restore the string/rod to its relaxed length.
Tension (as a transmitted force, as an action-reaction pair of forces, or as a restoring force) is measured in newtons in the International System of Units (or pounds-force in Imperial units). The ends of a string or other object transmitting tension will exert forces on the objects to which the string or rod is connected, in the direction of the string at the point of attachment. These forces due to tension are also called "passive forces". There are two basic possibilities for systems of objects held by strings: either acceleration is zero and the system is therefore in equilibrium, or there is acceleration, and therefore a net force is present in the system.
== Tension in one dimension ==
Tension in a string is a non-negative vector quantity. Zero tension is slack. A string or rope is often idealized as one dimension, having fixed length but being massless with zero cross section. If there are no bends in the string, as occur with vibrations or pulleys, then tension is a constant along the string, equal to the magnitude of the forces applied by the ends of the string. By Newton's third law, these are the same forces exerted on the ends of the string by the objects to which the ends are attached. If the string curves around one or more pulleys, it will still have constant tension along its length in the idealized situation that the pulleys are massless and frictionless. A vibrating string vibrates with a set of frequencies that depend on the string's tension. These frequencies can be derived from Newton's laws of motion. Each microscopic segment of the string pulls on and is pulled upon by its neighboring segments, with a force equal to the tension at that position along the string.
If the string has curvature, then the two pulls on a segment by its two neighbors will not add to zero, and there will be a net force on that segment of the string, causing an acceleration. This net force is a restoring force, and the motion of the string can include transverse waves that solve the equation central to Sturm–Liouville theory:
−
d
d
x
[
τ
(
x
)
d
ρ
(
x
)
d
x
]
+
v
(
x
)
ρ
(
x
)
=
ω
2
σ
(
x
)
ρ
(
x
)
{\displaystyle -{\frac {\mathrm {d} }{\mathrm {d} x}}{\bigg [}\tau (x){\frac {\mathrm {d} \rho (x)}{\mathrm {d} x}}{\bigg ]}+v(x)\rho (x)=\omega ^{2}\sigma (x)\rho (x)}
where
v
(
x
)
{\displaystyle v(x)}
is the force constant per unit length [units force per area] and
ω
2
{\displaystyle \omega ^{2}}
are the eigenvalues for resonances of transverse displacement
ρ
(
x
)
{\displaystyle \rho (x)}
on the string, with solutions that include the various harmonics on a stringed instrument.
== Tension of three dimensions ==
Tension is also used to describe the force exerted by the ends of a three-dimensional, continuous material such as a rod or truss member. In this context, tension is analogous to negative pressure. A rod under tension elongates. The amount of elongation and the load that will cause failure both depend on the force per cross-sectional area rather than the force alone, so stress = axial force / cross sectional area is more useful for engineering purposes than tension. Stress is a 3x3 matrix called a tensor, and the
σ
11
{\displaystyle \sigma _{11}}
element of the stress tensor is tensile force per area, or compression force per area, denoted as a negative number for this element, if the rod is being compressed rather than elongated.
Thus, one can obtain a scalar analogous to tension by taking the trace of the stress tensor.
== System in equilibrium ==
A system is in equilibrium when the sum of all forces is zero.
∑
F
→
=
0
{\displaystyle \sum {\vec {F}}=0}
For example, consider a system consisting of an object that is being lowered vertically by a string with tension, T, at a constant velocity. The system has a constant velocity and is therefore in equilibrium because the tension in the string, which is pulling up on the object, is equal to the weight force, mg ("m" is mass, "g" is the acceleration caused by the gravity of Earth), which is pulling down on the object.
∑
F
→
=
T
→
+
m
g
→
=
0
{\displaystyle \sum {\vec {F}}={\vec {T}}+m{\vec {g}}=0}
== System under net force ==
A system has a net force when an unbalanced force is exerted on it, in other words the sum of all forces is not zero. Acceleration and net force always exist together.
∑
F
→
≠
0
{\displaystyle \sum {\vec {F}}\neq 0}
For example, consider the same system as above but suppose the object is now being lowered with an increasing velocity downwards (positive acceleration) therefore there exists a net force somewhere in the system. In this case, negative acceleration would indicate that
|
m
g
|
>
|
T
|
{\displaystyle |mg|>|T|}
.
∑
F
→
=
T
→
−
m
g
→
≠
0
{\displaystyle \sum {\vec {F}}={\vec {T}}-m{\vec {g}}\neq 0}
In another example, suppose that two bodies A and B having masses
m
1
{\displaystyle m_{1}}
and
m
2
{\displaystyle m_{2}}
, respectively, are connected with each other by an inextensible string over a frictionless pulley. There are two forces acting on the body A: its weight (
w
1
=
m
1
g
{\displaystyle w_{1}=m_{1}g}
) pulling down, and the tension
T
{\displaystyle T}
in the string pulling up. Therefore, the net force
F
1
{\displaystyle F_{1}}
on body A is
w
1
−
T
{\displaystyle w_{1}-T}
, so
m
1
a
=
m
1
g
−
T
{\displaystyle m_{1}a=m_{1}g-T}
. In an extensible string, Hooke's law applies.
== Strings in modern physics ==
String-like objects in relativistic theories, such as the strings used in some models of interactions between quarks, or those used in the modern string theory, also possess tension. These strings are analyzed in terms of their world sheet, and the energy is then typically proportional to the length of the string. As a result, the tension in such strings is independent of the amount of stretching.
== See also ==
Continuum mechanics
Fall factor
Surface tension
Tensile strength
Traction (mechanics)
Hydrostatic pressure
== References == | Wikipedia/Tension_(mechanics) |
Revenge porn is the distribution of sexually explicit images or videos of individuals without their consent, with the punitive intention to create public humiliation or character assassination out of revenge against the victim. The material may have been made by an ex-partner from an intimate relationship with the knowledge and consent of the subject at the time, or it may have been made without their knowledge. The subject may have experienced sexual violence during the recording of the material, in some cases facilitated by psychoactive chemicals such as date rape drugs which also cause a reduced sense of pain and involvement in the sexual act, dissociative effects and amnesia.
The possession of the material may be used by the perpetrators to blackmail the subjects into performing other sexual acts, to coerce them into continuing a relationship or to punish them for ending one, to silence them, to damage their reputation, and/or for financial gain. In the wake of civil lawsuits and the increasing numbers of reported incidents, legislation has been passed in a number of countries and jurisdictions to outlaw the practice, though approaches have varied and been changed over the years. The practice has also been described as a form of psychological abuse and domestic violence, as well as a form of sexual abuse.
Revenge porn most commonly refers to the uploading of sexually explicit material to the Internet to humiliate and intimidate a subject who has broken off a relationship. The term is however also often broadly used to describe non-revenge scenarios, including nonconsensual pornography distributed by hackers or by individuals seeking profit or notoriety (often formally referred to as non-consensual intimate imagery, NCII, or image-based sexual abuse, IBSA). The images are usually accompanied by sufficient information to identify the target individual (a process known as doxing), typically names and locations, and can include risqué comments, links to social media profiles, home addresses, and workplaces. In some cases victims are exposed to workplace discrimination, cyberstalking or physical attack. Some companies search the Internet for potential sources of bad publicity, resulting in many victims of revenge porn losing their jobs and finding themselves effectively unhirable. Some academics argue that the term "revenge porn" should not be used, and instead that it should be referred to as "image-based sexual abuse."
Jurisdictions which have passed laws against revenge porn include Canada, Germany, Italy, Israel, Singapore, Spain, the United Kingdom, the United States (49 out of 50 states of the United States, Washington, D.C., the U.S. military and U.S. overseas territories including Puerto Rico and Guam). Australia has also passed a law at the Commonwealth level that commenced on 1 September 2018. The Australian states and territories of South Australia, Victoria, New South Wales, the Australian Capital Territory, the Northern Territory, Queensland, Western Australia, and Tasmania, have complementary state level laws that criminalize this behaviour. Furthermore, Australia also has a civil penalties scheme.
In recent years the rise of computer-generated imagery and synthetic media technology has raised concerns about the rise of revenge porn made using deepfake pornography techniques. As of 2023 in the U.S. states of New York, Virginia, and California, it is illegal to disseminate pornographic images created using image generation technology without the consent of subjects depicted in the image. In fact, law enforcement officials in San Francisco have initiated lawsuits against websites offering "undressing" image generation used to make deepfake porn.
== Background ==
In the 1980s, Hustler magazine began a monthly feature of reader-submitted images of naked women called "Beaver Hunt". Beaver Hunt photographs were often accompanied by details about the woman, like her hobbies, her sexual fantasies, and sometimes her name. Not all of the women featured in Beaver Hunt submitted their own images and several women sued the magazine for publishing their photographs without their permission, or without verifying information on forged consent forms.
Two decades later, Italian researcher Sergio Messina identified "realcore pornography", a new genre consisting of images and videos of ex-girlfriends distributed through Usenet groups. In 2008, amateur porn aggregator XTube began receiving complaints that pornographic content had been posted without subjects' consent. Several sites began staging consensual pornography to resemble revenge porn, as well as hosting "authentic" user-submitted content.
Revenge porn began garnering international media attention when Hunter Moore launched the website IsAnyoneUp in 2010. The site featured user-submitted images, and was one of the first sites to adopt the model initiated by Beaver Hunt: IsAnyoneUp often included identifying information, such as the subjects' names, employers, addresses and links to social networking profiles. Activist Charlotte Laws was the first person to speak out against Moore and one of the first people to publicly support revenge porn victims. This prompted backlash from some of Moore's devotees, who stalked Laws and sent her death threats. Laws became known around the world as the "Erin Brockovich of revenge porn" and she was one of the first activists to meet with legislators in an effort to get laws passed against revenge porn.
In February 2015, the social media site and online bulletin board Reddit announced a change to its privacy policy to ban the posting of sexually explicit content without the consent of those depicted. The announcement was made after a company meeting at which the issue of "illicit pornography—pictures and video—was a burning one". In March 2015, Twitter followed suit with new rules to address the posting of unauthorized content and specifically revenge porn. Starting March 11 of that year, Twitter stated it would immediately remove "any 'link to a photograph, video, or digital image of you in a state of nudity or engaged in any act of sexual conduct' that has been posted without consent." According to a Washington Post article, the changes were in response to growing concerns "that [Twitter] has not done enough to prevent bad behavior on its site."
In June 2015, Google announced it would remove links to revenge porn on request. Microsoft followed suit in July. Both have placed forms on-line for victims to complete. Together the two organizations account for nearly 90% of the internet search market in the U.S.
The term "revenge porn" is controversial because those who share images without permission may be motivated by profit, notoriety, entertainment, or other goals besides revenge; and because not all visual depictions of nudity or sexual activity are pornographic.
== Advocacy ==
The website endrevengeporn.org was founded by Holly Jacobs, a revenge porn victim, to campaign for the criminalization of revenge porn, which it considered a form of sexual abuse. Jacobs also founded the Cyber Civil Rights Initiative (CCRI), a nonprofit organization that seeks to challenge cyber harassment. Danielle Citron, known for her discourse on cyber harassment as a civil rights issue, the vice-president of the CCRI. Mary Anne Franks, CCRI's president and Legislative & Tech Policy Director, has been heavily involved with legislative and policy efforts to combat revenge porn. Dr. Laura Hilly and Kira Allmann of the Oxford Human Rights Hub have characterized revenge porn as a kind of gendered hate speech designed to silence women. An article of theirs argues that this stifling of free expression is often ignored in debates over revenge porn. Dr. Charlotte Laws, often called "the Erin Brockovich of revenge porn", was a CCRI board member until 2016. She is perhaps the first victims' advocate and one of the first to meet with elected officials in an effort to get legislation passed against nonconsensual pornography.
Katie Hill, U.S. representative for California, announced in late 2019 she would advocate against revenge porn.
While not solely focused on revenge porn, the non-profit organization Without My Consent provided legal resources related to it and lobbies to protect the privacy and free speech rights of online harassment victims. In 2019, Without My Consent ceased operating and transferred to CCRI all of the comprehensive resources it had developed to aid victims of online abuse. Since 2012, there has also been a website Women Against Revenge Porn, calling itself "not an organization or a business", which has been cited as an advocacy group for people exposed in revenge porn. In late 2014, Elisa D'Amico and David Bateman, partners at the law firm K&L Gates, launched the Cyber Civil Rights Legal Project (CCRLP), a project offering free legal help to victims of revenge porn.
To better facilitate the introduction of relevant legislation, some anti-revenge porn activists have called upon others in their community to use gender-neutral language more often when discussing the issue. The term "revenge porn" itself has also come under fire. The CCRI for instance prefers the term "nonconsensual pornography". In analogy with "child sexual abuse images" being the preferred term for child pornography, McGlynn and Rackley proposed "image-based sexual abuse". Along with journalist Sarah Jeong, they have argued that it is harmful to associate revenge porn with pornography which revolves around consent. Jeong also considers it a mistake for activists to focus on revenge porn itself as the main problem, rather than the underlying culture which leads to its subjects being socially ostracized.
In the Australian Capital Territory, an electronic petition was started in March 2017 that called upon the A.C.T. Legislative Assembly to consider criminalizing the non-consensual disclosure of sexual images and videos. The A.C.T Legislative Assembly consequently passed the Crimes (Intimate Image Abuse) Amendment Act (2017) (ACT) that criminalised the distribution, or threatened distribution, of intimate photos and videos on 16 August 2017.
== Legislation ==
Laws banning revenge porn have been slow to emerge. Contributing factors include a lack of understanding about the gravity of the problem, free speech concerns, belief that existing law provides adequate protection, a lack of care, historically, for women's issues, and "misunderstandings of First Amendment doctrine" (Citron & Franks). The American Civil Liberties Union and the Electronic Frontier Foundation have drawn attention to the implications for free speech if legislation is too broad.
One concern with revenge porn laws is that they may not be tailored narrowly enough to satisfy the strict scrutiny applicable to content-based restrictions on speech. Prohibition of revenge porn may not be constitutional according to the Miller v. California decision if the porn does not categorically appeal to the prurient interest; if it is not, in itself, patently offensive; or if it has literary or political value.
=== Africa ===
In South Africa, the Films and Publications Amendment Act, 2019 makes it a crime to distribute a private sexual photograph or film without the consent of the pictured individual and with the intent to cause them harm. The penalty is a fine of up to R150,000 and/or up to two years' imprisonment; or double that if the victim is identifiable in the photograph or film.
=== Asia ===
Since 2009, the Philippines has criminalized copying, reproducing, sharing or exhibiting sexually explicit images or videos over the Internet without written consent of the individual depicted.
Japan passed a bill in November 2014 which made it a crime to communicate "a private sexual image of another person" without consent.
In South Korea the distribution of revenge porn is punishable by up to three years' imprisonment or by a fine of up to 5 million South Korean won. If the subject is filmed illicitly the penalty is up to ten years in prison or a fine of up to 10 million won ($8,900; £6,900). The use of hidden cameras for illicitly filming people, known as "molka", is widespread in the country and in 2018 more than 6,000 incidents of spy-cam porn were being reported to the police annually, with only 2% of reported cases leading to a prison sentence. The website Sora.net specialised in the publishing of spy-cam porn until it was banned in 2016 following a campaign against it. Some of those depicted had committed suicide. In May 2018, ten thousand women demonstrated in Seoul demanding increased official action against digital sex crime. In October 2018 a petition of over 200,000 signatories called for increased punishment for the possession of revenge porn, regardless of whether it had been distributed.
==== Singapore ====
Singapore passed the Criminal Law Reform Act on 6 May 2019, which includes the criminalisation of revenge porn. Penalties include a jail term of up to five years with fines and caning as a sentencing option. If the crime is committed against a victim under 14 years of age, a mandatory jail term will be imposed. The Act took effect on 1 January 2020.
=== Australia ===
Sharing sexual images or videos without consent is unlawful under three different, but parallel, types of law in Australia; the Civil Law, the Criminal Law, and a Civil Penalties scheme.
Under the Civil Law, the Supreme Court of Western Australia decision in the case of Wilson v Ferguson, delivered on 16 January 2015, is specific precedent that establishes that the non-consensual publication of sexual images or videos on the internet is unlawful. In that case, a defendant shared sexual images and videos of the plaintiff on social media. The Court decided that the publication of "explicit images of a former partner which had been confidentially shared between the sexual partners during their relationship" constituted a breach of an equitable obligation of confidence. The Court granted an injunction prohibiting further publication and awarded equitable compensation to the plaintiff. The defendant was found liable for A$48,404 in damages, plus costs. This case was successfully argued on grounds previously established by the case of Giller v Procopets, which was argued on the equity of breach of confidence and tort grounds.
Under the Criminal Law, the Parliaments in the Australian States and Territories of South Australia, Victoria, New South Wales, the Australian Capital Territory, the Northern Territory, Queensland, Western Australia, and Tasmania, have all passed laws that amend the relevant statutory criminal law to criminalise the non-consensual sharing of sexual images or videos. Furthermore, the Parliament of Australia has also passed a law that amends the Commonwealth statutory criminal law (which operates in parallel to State and Territory criminal law) to criminalise the non-consensual sharing of sexual images or videos. Most jurisdictions provide for higher sentences where the image that is shared is of a child. The particular law in each of these jurisdictions is described below, in chronological order of their enactment.
In March 2013, the Parliament of South Australia passed the Summary Offences (Filming Offences) Amendment Act (2013) (SA) that specifically created a criminal offence for distributing an invasive image or video without consent, which commenced on 10 May 2013. The distribution of an invasive image offence is contained in s. 26C of the Summary Offences Act (1953) (SA), and the maximum penalty is A$10,000 or imprisonment for 2 years. In September 2016, the Parliament of South Australia further passed the Summary Offences (Filming and Sexting Offences) Amendment Act (2016) to create a criminal offence for threatening to distribute an invasive image or video, which commenced on 28 October 2018. The threatening to distribute offence is contained in s. 26DA of the Summary Offences Act (1953) (SA), and the maximum penalty is A$5,000 or imprisonment for 1 year.
On 15 October 2014, the Parliament of Victoria passed the Crimes Amendment (Sexual Offences and Other Matters) Act (2014) (Vic) that created specific criminal offences for distributing, or threatening to distribute, a sexual image or video without consent, which commenced on 3 November 2014 (and was repealed on 6 September 2022). The distribution of an intimate image offence was contained in s. 41DA of the Summary Offences Act (1966) (Vic), and the maximum penalty was imprisonment for 2 years. The threatening to distribute an intimate image offence was contained in s. 41DB of the Summary Offences Act (1966) (Vic), and the maximum penalty was imprisonment for 1 year. On 30 August 2022, the Parliament of Victoria further passed the Justice Legislation Amendment (Sexual Offences and Other Matters) Act (2022) (Vic) that amended the Summary Offences Act (1966) (Vic), which commenced on 30 July 2023. The amendment relocated the criminal offence of distributing an intimate image to s. 53S of the Crimes Act (1958) (Vic), and the offence of threatening to distribute an intimate image to s. 53T of the Crimes Act (1958) (Vic). The maximum penalty for either offence is imprisonment for 3 years. This Act also created a specific criminal offence for producing an intimate image without consent. The producing an intimate image offence is contained in s. 53R of the Crimes Act (1958) (Vic), and the maximum penalty is imprisonment for 3 years. Furthermore, this Act created a disposal order scheme. The intimate image disposal order is contained in s. 53Z of the Crimes Act (1958) (Vic).
On 21 June 2017, the Parliament of New South Wales passed the Crimes Amendment (Intimate Images) Act (2017) (NSW) that created specific criminal offences for distributing, or threatening to distribute, or threatening to record, an intimate image or video without consent, and provided for Rectification Orders that empower a Court to order the removal and destruction of the intimate image or video, which commenced on 28 August 2017. The distribution of an intimate image offence is contained in s. 91Q of the Crimes Act (1900) (NSW), and the maximum penalty is an A$11,000 fine, or imprisonment for 3 years, or both. The threatening to distribute, or threatening to record an intimate image offences, are contained in s. 91R of the Crimes Act (1900) (NSW), and the maximum penalty for either offences is an A$11,000 fine, or imprisonment for 3 years, or both. The contravention of a Rectification Order offence is contained in s. 91S of the Crimes Act (1900) (NSW), and the maximum penalty is an A$5,500 fine, or imprisonment for 2 years, or both.
On 16 August 2017, the Legislative Assembly of the Australian Capital Territory passed the Crimes (Intimate Image Abuse) Amendment Act (2017) (ACT) that created specific criminal offences for distributing, or threatening to distribute, or threatening to capture, an intimate image or video without consent, and provided for Rectification Orders that empower a Court to order the removal and destruction of the intimate image or video, which commenced on 30 August 2017. The distribution of an intimate image offence is contained in s. 72C of the Crimes Act (1900) (ACT), and the maximum penalty is A$45,000 or imprisonment for 3 years, or both. The threatening to distribute, or threatening to capture, an intimate image offences are contained in s. 72E of the Crimes Act (1900) (ACT), and the maximum penalty is A$45,000 or imprisonment for 3 years, or both. The contravention of a Rectification Order offence is contained in s. 72H of the Crimes Act (1900) (ACT), and the maximum penalty is an A$30,000 fine, or imprisonment for 2 years, or both.
On 22 March 2018, the Legislative Assembly of the Northern Territory passed the Criminal Code Amendment (Intimate Images) Act (2018) (NT) that created specific criminal offences for distributing, or threatening to distribute, an intimate image or video without consent, and provided for Rectification Orders that empower a Court to order the removal and destruction of the intimate image or video, which commenced on 9 May 2018. The distribution of an intimate image offence is contained in s. 208AB of the Criminal Code Act (1983) (NT), and the maximum penalty is imprisonment for 3 years. The threatening to distribute an intimate image offence is contained in s. 208AC of the Criminal Code Act (1983) (NT), and the maximum penalty is imprisonment for 3 years. The contravention of a Rectification Order offence is contained in s. 208AE of the Criminal Code Act (1983) (NT), and the maximum penalty is imprisonment for 2 years.
On 16 August 2018, the Parliament of the Commonwealth of Australia passed the Enhancing Online Safety (Non‑consensual Sharing of Intimate Images) Act (2018) (Cth) that created specific criminal offences (that operates in parallel to State and Territory criminal law) for distributing, or threatening to distribute, a sexual image or video without consent, which commenced on 1 September 2018. The distribution of a private sexual image offence is contained in s. 474.17A of the Criminal Code Act (1995) (Cth), and the maximum penalty is imprisonment for 5 years.
On 13 February 2019, the Parliament of Queensland passed the Criminal Code (Non-consensual Sharing of Intimate Images) Amendment Act (2019) (Qld) that created specific criminal offences for distributing, or threatening to distribute, an intimate image or video without consent, and provided for Rectification Orders that empower a Court to order the removal and destruction of the intimate image or video, which commenced on 21 February 2019. The distribution of an intimate image offence is contained in s. 223 of the Criminal Code Act (1899) (Qld), and the maximum penalty is imprisonment for 3 years. The threatening to distribute an intimate image offence is contained in s. 229A of the Criminal Code Act (1899) (Qld), and the maximum penalty is imprisonment for 3 years. The contravention of a Rectification Order offence is contained in s. 229AA of the Criminal Code Act (1899) (Qld), and the maximum penalty is imprisonment for 2 years.
On 19 February 2019, the Parliament of Western Australia passed the Criminal Law Amendment (Intimate Images) Act (2018) (WA) that created specific criminal offences for distributing, or threatening to distribute, an intimate image or video without consent, and provided for Rectification Orders that empower a Court to order the removal and destruction of the intimate image or video, which commenced on 15 April 2019. The distribution of an intimate image offence is contained in s. 221BD of the Criminal Code Act Compilation Act (1913) (WA), and the maximum penalty is imprisonment for 3 years. The threatening to distribute an intimate image offence is contained in s. 338 of the Criminal Code Act Compilation Act (1913) (WA), and the maximum penalty is imprisonment for 3 years. The contravention of a Rectification Order offence is contained in s. 221BE of the Criminal Code Act Compilation Act (1913) (WA), and the maximum penalty is imprisonment for 1 year and an A$12,000 fine.
On 19 September 2019, the Parliament of Tasmania passed the Criminal Code Amendment (Bullying) Act (2019) (Tas) that extended the criminal offence of stalking to include distributing an offensive image or video, which commenced on 8 September 2019. The distribution of an offensive image offence is contained in s. 192(1) of the Criminal Code Act (1924) (Tas), and the offence is a serious indictable crime that can only be tried on indictment in the Supreme Court. The threat offence is contained in s. 192(1)(ea) of the Criminal Code Act (1924) (Tas), and the offence is a serious indictable crime that can only be tried on indictment in the Supreme Court.
Under the civil penalties scheme, Australians can report the posting, or threatened posting, of sexual images and videos without consent, to the Australian Government Office of the eSafety Commissioner. The eSafety Commissioner is empowered to receive and investigate complaints, issue take-down notices, and enforce civil penalties against individuals and corporations who fail to comply. In July 2015, the Australian Government established the Office of the eSafety Commissioner. In October 2017, the Office of the eSafety Commissioner launched the Image Based Abuse online reporting portal, which enables Australians to report non-consensually shared sexual images and videos that had been posted to social media, or websites, and enables the eSafety Commissioner to seek their removal. On 16 August 2018, the Parliament of Australia passed Enhancing Online Safety (Non‑consensual Sharing of Intimate Images) Act (2018) (Cth) that establishes a civil penalties scheme. Under this law, the eSafety Commissioner is empowered to investigate a complaint, or an objection, regarding the non-consensual sharing of intimate images or videos on social media, by email or SMS/MMS, on websites, or peer-to-peer file-sharing services. Furthermore, under this law, a person who non-consensually posts, or threatens to post, an intimate image or video may be liable for a civil penalty. This law also empowers the eSafety Commissioner to issue removal notices requiring providers of a social media service, a relevant electronic service, or a designated internet service, to remove the intimate image from the service. Similar powers can be enforced against end-users, and hosting service providers. Civil penalties for individuals are up to a maximum of A$105,000 and for corporations are up to a maximum of A$525,000.
=== North America ===
==== Canada ====
In 2014, with the passage of the Protecting Canadians from Online Crime Act, Canada criminalized the "non-consensual distribution of intimate images" that were made under a "reasonable expectation of privacy".
==== United States ====
Tort, privacy, copyright, and criminal laws offer remedies against people who submit revenge porn. 49 states (all except South Carolina) have laws against revenge porn as of June 2024.
For example, New Jersey law prohibits both the capture and the distribution of sexually explicit photographs and films by any person, "knowing that he is not licensed or privileged to do so" and without the subjects' consent. The law was used to prosecute Dharun Ravi, the Rutgers student who distributed webcam footage of his roommate Tyler Clementi engaging in sexual activity, after which Clementi died by suicide. The law has also been used to prosecute several men who allegedly distributed revenge porn of their ex-girlfriends.
Mary Anne Franks, a law professor and constitutional scholar who drafted the model legislation and advised legislators in the majority of the above states, emphasizes that many of these laws are still deeply flawed.
Representatives from the Department of Justice, California's Office of the Attorney General, 50 major technology companies, victim advocates, and legislative and law enforcement leaders joined in 2015 to form a Cyber Exploitation Working Group, and have announced the creation of a working hub "to combat so-called cyber exploitation – the practice of anonymously posting explicit photographs of others online, often to extort money from the victims."
As of October 1, 2022, a new section of the US Federal Code, 15 U.S.C. § 6851 Civil action relating to disclosure of intimate images, went into effect. This was passed via Section 1309 of the Consolidated Appropriations Act, 2022 and amended the Violence Against Women Act, allowing victims of revenge porn to file civil suits against those who released the materials. Victims may sue for up to US$150,000 in actual damages as well as legal fees; restraining orders and injunctions may also be issued to temporarily or permanently halt any further distribution or disclosure. It is the first Federal law concerning revenge porn and helps address the patchwork of state laws in effect at the time of its passage. The burden of bringing such a suit is still on the victim and the code does not formally criminalize the release of revenge porn. Communications platforms, including websites, would be liable if they solicited such material or if they deal predominantly in revenge porn. Importantly, the legal code includes specific wording which holds that a victim's allowance of such materials to be created and any instances where the victim shared that material with specific individuals do not imply wholesale consent to share the material with any other individuals, two commonly anticipated defenses which defendants may raise.
In July 2024, the bipartisan TAKE IT DOWN Act act was introduced in the U.S. Senate. The act would provide federal protections to victims of AI-generated deep-fake pornography. It would criminalize the publication of AI-generated deep-fake images without the subject's consent. In addition, it would require social media sites to create processes for victims to have deep-fake images removed. Though it failed to pass both Houses by the end of 2024, it was reintroduced in 2025, unanimously passed the Senate and passed the House on a 409-2 vote by April 28, 2025. President Donald Trump signed the act into law on May 19, 2025.
Observers have also noted the shame which may make many victims reluctant to report or pursue such investigations. While victims of sexual abuse can have their identities kept out of court proceedings, which will only refer to them as Jane Doe or John Doe, few such safeguards exist for victims of revenge porn. Depending on jurisdiction, images in court cases may be entered as evidence and become publicly viewable. Suggestions have been made to revise evidentiary laws to allow anonymization of plaintiffs and de-identification of images entered as evidence. 15 U.S.C. § 6851 specifically allowed for injunctions to preserve plaintiff anonymity when filing civil suits in Federal court.
===== Criminal prosecutions =====
Several well-known revenge porn websites, including IsAnyoneUp and the Texxxan, have been taken down in response to actual or threatened legal action. The former was investigated by the FBI after anti-revenge porn activist Charlotte Laws uncovered a hacking scheme associated with the website. Indictments for fifteen felonies were handed down under the Computer Fraud and Abuse Act in January 2014 for the site owner and his accomplices, and the trial was initially set to begin in November 2014 in Los Angeles. Hunter Moore, the owner of IsAnyoneUp pleaded guilty to hacking and identity theft in early 2015. Moore was sentenced to two and a half years in prison on 2 December 2015. By May 2017, Moore was out of prison.
In December 2013, California Attorney General Kamala Harris charged Kevin Bollaert, who ran the revenge porn website UGotPosted, with 31 felony counts, including extortion and identity theft. In March 2014, because the victim was under eighteen years old in the photos, a court in Ohio awarded damages of $385,000 against Bollaert. In April 2015 Bollaert was sentenced to 18 years in prison. "Sitting behind a computer, committing what is essentially a cowardly and criminal act, will not shield predators from the law or jail", said Attorney General Harris following the verdict. Also in California, a man named Noe Iniguez was given jail time for posting a naked photo of his ex-girlfriend on her employer's Facebook page.
Casey Meyering, the operator of revenge porn website WinByState, was arrested in Oklahoma in 2014 and extradited to Napa County. Meyering's website invited users to submit nude photos of ex-girlfriends and other women, with the photos categorized by state. He would then make the women featured on his website pay $250 to have their photos taken down. There were about 400 images of California women on the website, including at least one in Napa Valley, where California Attorney General Kamala Harris had filed the case. After originally pleading not guilty, on 8 May 2015, the 28-year-old man pleaded no contest to one count of extortion, three counts of attempted extortion, and one count of conspiracy. He was sentenced to three years' imprisonment as of early June 2015.
In August 2023, a jury in Harris County, Texas, returned a $1.2 billion verdict on behalf of a woman identified as "D.L." or "Jane Doe" in court filings. The unanimous verdict found that Marques Jamal Jackson had distributed revenge porn in violation of the Texas' revenge porn law. The verdict included $200 million in compensatory damages and $1 billion in punitive damages. According to the lawsuit, Jackson posted images of his former girlfriend on social media platforms and websites, including a pornography site, and in a public Dropbox folder. He created fake social media pages and email accounts to share the material with her family, friends and co-workers and sent them a link to the Dropbox folder. He also tagged her employer and personal gym on social media posts.
===== Tort and privacy law =====
States without specific laws about revenge porn have seen lawsuits alleging invasion of privacy, public disclosure of private fact and intentional infliction of emotional distress against the individuals who uploaded the images. Forty states, including California, New Jersey, and New York, have anti-cyberharassment laws that may be applicable to cases of revenge porn.
In February 2014, a US$500,000 settlement was awarded to a Texas woman who brought suit against her ex-boyfriend for posting video and photos of her on the Internet. The state did not have a specific "revenge porn" law at the time of the lawsuit. California has a private right of action in tort for acts of revenge pornography within the civil code, as well as a specific criminal statute punishing revenge pornography as an invasion of privacy.
===== Communications Decency Act §230 =====
Some revenge porn lawsuits have named service providers and websites as defendants alongside individuals who uploaded the images. Section 230 (§230) of the Communications Decency Act shields websites and service providers from liability for content posted by users providing they are not themselves co-creators of the content. If user-generated content posted to a website does not violate copyright or federal criminal laws, sites have no obligation to remove the content under §230.
===== Copyright =====
According to a survey conducted by the Cyber Civil Rights Initiative, an estimated 80% of revenge porn pictures and videos are taken by the subjects themselves. Those individuals can bring actions for copyright infringement against the person who uploaded their nude or semi-nude "selfies". American victims may file Digital Millennium Copyright Act takedown notices with service providers. Revenge porn site MyEx.com has been a defendant in a copyright infringement case.
===== First Amendment and anti-SLAPP =====
Some free speech advocates object to revenge porn laws on First Amendment grounds, citing the fact that US laws restricting expression have a history of being overturned. Journalist Sarah Jeong argues that new criminal laws meant to combat revenge porn are likely to be overbroad, resulting in unintended consequences.
Revenge porn uploaders and websites may also challenge lawsuits using state protections against strategic lawsuit against public participations (anti-SLAPP laws), which allow defendants to counter lawsuits aimed at stifling free speech.
=== Europe ===
Many European countries have broad privacy statutes that may be applicable to revenge porn. France also criminalizes the willful violation of the intimate private life of another by "transmitting the picture of a person who is within a private place, without the consent of the person concerned". A German High Court made a May 2014 ruling that intimate photographs of partners should be deleted if the partner so requests. In 2019, after a citizen-led campaign, Italy approved a law punishing whoever disseminates images or videos with sexually explicit content, intended to remain private, without the consent of the persons represented, with a jail sentence from one to six years and a fine from €5,000 to €15,000.
In 2020, Pornhub removed 10 million videos uploaded by unverified users after accusations from the public and refusal of Mastercard and Visa to work with site.
==== Ireland ====
In 2020 Ireland passed the Harassment, Harmful Communications and Related Offences Act 2020, which introduced two new criminal offences:
The taking, distribution, publication or threat to distribute intimate images without consent, and with intent to cause harm to the victim - this carries a maximum penalty of an unlimited fine and/or seven years imprisonment.
The taking, distribution or publication of intimate images without consent without a requirement that the person intended to cause harm to the victim - this carries a maximum penalty of a fine of €5,000 fine and/or up to twelve months in prison.
It is irrelevant if a person consented to the taking of an image if they did not consent to it being later being distributed.
It is an aggravating factor for sentencing if the perpetrator was in an intimate relationship with the victim.
The bill came into effect in 2021.
==== Malta ====
A law criminalising revenge porn in Malta entered into force in November 2016. Article 208E of the Maltese Criminal Code punishes whoever, with an intent to cause distress, emotional harm or harm of any nature, discloses a private sexual photograph or film without the consent of the person or persons displayed or depicted in such photograph or film. Such person would, on conviction be liable to imprisonment for a term of up to two years or to a fine of not less than €3,000 and not more than €5,000, or to both such imprisonment and fine.
==== United Kingdom ====
===== England and Wales =====
In 2012, the English singer-songwriter Tulisa Contostavlos obtained an injunction preventing the distribution of a sex tape of her and a former lover that had been published on the internet. The case was set to include considerable damages, but was settled out of court before it could be considered.
In April 2014, UK charities including The National Stalking Helpline, Women's Aid, and the UK Safer Internet Centre reported increased use of revenge porn websites. Women's Aid Charity Chief Executive Polly Neate stated, "To be meaningful, any attempt to tackle revenge porn must also take account of all other kinds of psychological abuse and controlling behaviour, and revenge porn is just another form of coercive control. That control is central to domestic violence, which is why we're campaigning for all psychological abuse and coercive control to be criminalised". In July Chris Grayling, the Secretary of State for Justice, announced plans to "take appropriate action" to address revenge porn in Britain. A House of Lords Committee, in a report on social media and the law, subsequently called for clarification from the DPP as to when revenge porn becomes a crime.
The Criminal Justice and Courts Act 2015 received Royal Assent. Section 33 of the Act makes it an offence in England and Wales to disclose private sexual photographs and films without the consent of the individual depicted and with the intent to cause distress. There is a maximum sentence of two years' imprisonment.
On 23 April 2015, a seminar was held in Westminster on the new legislation. The seminar was organised by the Oxford Human Rights Hub and co-hosted with the law firm McAllister Olivarius, the End Violence Against Women Coalition, the University of Durham, and the University of Birmingham. The seminar called for the law to be extended to cover upskirting, a change that was subsequently made with the passing of the Voyeurism (Offences) Act 2019.
In June 2015 Chrissy Chambers, a YouTube star from the United States, pursued a civil suit against her British ex-boyfriend who posted sexually-explicit videos taken without her knowledge or consent to Facebook where they were repeatedly shared. Chambers chose to pursue a civil case as the Criminal Justice and Courts Act 2015 does not apply retroactively to content posted prior to its passage. She was represented by McAllister Olivarius and in January 2018 won "substantial damages". Drawing on this and other cases, Dr. Ann Olivarius of the same firm gave a TEDxReading talk on "Revenge Porn: The Naked Truth".
Between April 2015 (the date that section 33 of the Criminal Justice and Courts Act 2015 came into force) and December 2015 the number of reported incidents of revenge pornography in England and Wales was 1,160. However, 61% of them resulted in no action being taken and the number of people prosecuted for disclosing private sexual images during the legislation's first year was 206. It emerged that cases of those who had been victims of revenge porn before April 2015 were not pursued under the new law, causing criticism that perpetrators "got away with" their crimes when committed before the Act came into force. Before April 2015, the law most applicable to revenge porn, specifically image-based sexual abuse, was the 1988 Malicious Communication Act, and "With police officers' understanding of revenge porn now being based on the newer legislation, prosecution under the Malicious Communications Act for similar cases is less likely to be considered. And so police officers may be less likely to consider alternative legislation for those cases which predate April 2015."
The Revenge Porn Helpline was set up in 2015. In 2019 it was announced that the Law Commission would examine the possibility of reclassifying revenge porn from a "communications crime" to a sexual offence, thus giving victims anonymity.
===== Scotland =====
In Scotland, revenge porn became a specific offence in April 2016 with the adoption of the Abusive Behaviour and Sexual Harm Act, which came into force in July 2017.
===== Northern Ireland =====
In Northern Ireland, revenge porn was made a crime in February 2016 through the amendment of an existing law.
== Prenuptial agreements ==
Some couples draft "social media" prenuptial agreements, which may include provisions relating to revenge porn. Clauses may state that couples agree not to share photos or posts that are likely to harm a spouse's professional reputation.
== In other media ==
The novel The Drowning Pool (1950) by Ross Macdonald, part of the series starring fictional detective Lew Archer, features a subplot of a woman trying to stop distribution of a sexual film taken without her knowledge.
In S1E5 of the television series Sex Education, an intimate image of a high school student is distributed to her classmates with the threat of revealing her identity. Several characters work together to find the culprit. During the school assembly at the end of the episode, many students claim that the image is of them to protect their classmate.
In 2021, the BBC film Zara McDermott: Revenge Porn came out, in which Zara McDermott recalled the experience of having her nude photos leaked as a teenager.
== See also ==
Fake nude photography
Online shaming
Participatory surveillance
Deepfake pornography
Generative AI pornography
== References ==
== Further reading ==
Citron, Danielle Keats (February 2009). "Cyber Civil Rights" (PDF). Boston University Law Review. 89 (1): 61–126.
Citron, Danielle Keats; Franks, Mary Anne (2014). "Criminalizing Revenge Porn". Wake Forest Law Review. 49 (2): 345–392.
Hayward, Philip; Rahn, Alison (January 2015). "Opening Pandora's Box: pleasure, consent and consequence in the production and circulation of celebrity sex videos". Porn Studies. 2 (1): 49–61. doi:10.1080/23268743.2014.984951.
Matsui, Shigenori (April 2015). "The Criminalization of Revenge Porn in Japan". Washington International Law Journal. 24 (2): 289–318. Archived from the original on 9 July 2020.
McGlynn, Clare; Rackley, Erika (2017). "Image-Based Sexual Abuse" (PDF). Oxford Journal of Legal Studies. 37 (3): 534–561. doi:10.1093/ojls/gqw033. ISSN 0143-6503.
Rotenberg, Marc; Jacobs, David (2013). "Updating the Law of Information Privacy: The New Framework of the European Union" (PDF). Harvard Journal of Law and Public Policy. 36 (2). Archived from the original (PDF) on 2 June 2014. Retrieved 28 November 2013.
Wolf, Brittany (Winter 2014). "Free Speech versus Human Dignity: Comparative Perspectives on Internet Privacy" (PDF). Tulane Journal of International and Comparative Law. 23 (1): 251–282. Archived from the original (PDF) on 30 June 2015. | Wikipedia/Revenge_pornography |
The split attraction model (SAM) is a model in psychology that distinguishes between a person's romantic and sexual attraction, allowing the two to be different from each other.
== History and identity ==
The first recorded conceptualization of orientation that took into account split attraction was in 1879 by Karl Heinrich Ulrichs, a German writer who published 12 books on non-heterosexual attraction. In these books, Ulrichs has presented several classifications that are quite similar to modern LGBTQIA+ identities. Among his works, he described people who are "konjunktiver Uranodioning" and "disjunktiver Uranodioning" or conjunctive bisexuality and disjunctive bisexuality. The former is described as having tender and passionate feelings for both men and women, which would be a biromantic bisexual in modern times. The second is one who has tender feelings for people of the same gender/sex, but 'in love' feelings for people of a different gender/sex, which would now be a heteroromantic homosexual. However, the Ulrichs model never became popular due to its complexity.
A newer example of the separation of sexual and romantic attractions was in 1979 by psychologist Dorothy Tennov, with the publication of her book Love and Limerence – the Experience of Being in Love. In the book, Tennov described limerence as a form of attraction that could be described as a crush on someone. Although Tennov saw sex as part of limerence, she recognized that it was not its main focus. The term "non-limerent" is sometimes considered the precursor of aromantic.
The modern concept of the split attraction model was coined by the asexual and aromantic communities to better describe their identities within the community and to others. The term likely emerged around 2015, though the concept of split attractions had been in use since the origination of the term aromantic in 2005. The model helps people explain how they can still experience certain aspects of one attraction without the need for the other to be a match. A recent research study looked deeper into the relationships of asexuals to help explain how people still form meaningful connections, despite deviance of societal norms.
Relationships formed by people that identify under the split attraction model are often considered outside the norm and may include forms of committed friendships or intimate non-romantic relationships such as queerplatonic relationships.
In a practical application of the model, people of the community commonly refer to themselves by two terms to indicate the differing romantic and sexual attraction; examples include aromantic asexual, colloquially shortened aro-ace, panromantic demisexual or aromantic bisexual. Specific terms exist, such as varioriented and perioriented, describing those with different or similar orientations, respectively. For example, a homoromantic bisexual would be varioriented, while a heteroromantic heterosexual would be labeled as perioriented.
The concept and term are most commonly used within the LGBTQIA+ community, but more recent research found that it may also apply to people outside of the community that are just not yet familiar with the concept.
== Research ==
The concept that there is a distinction between romantic orientation and sexual orientation has not been studied extensively. American psychologist Lisa M. Diamond, who focuses her studies on sexual orientation and identity, has stated that a person's romantic orientation can differ from whom the person is sexually attracted to. While there is limited research on the discordance between sexual attraction and romantic attraction in individuals, the possibility of fluidity and diversity in attractions have been progressively recognized.
In a 2022 book edited by psychologists Angela M. Schubert and Mark Pope, authors Stacey Litam and Megan Speciale refer to an article by Michael Paramo published in Aze that identifies other forms of attraction beyond sexual and romantic attraction, including aesthetic, emotional, intellectual, and sensual attraction, to argue that these forms of attraction should also be considered in interpersonal relationships. Paramo argued in a 2024 book that splitting attraction can influence people to re-imagine their relationships differently when forms of attraction are not placed in a hierarchy.
A 2022 study found that while there is some concordance between romantic orientation and sexual orientation, the two were not a complete match, suggesting that the experience of split attraction between romantic and sexual orientation exists in both asexual and non-asexual people. A 2023 study noted that there is a general misunderstanding that different forms of attraction can exist concurrently both within and external to the LGBTQ community.
== See also ==
Aromanticism
Asexuality
Queerplatonic relationship
Romantic orientation
Sexual orientation
== References ==
== Further reading ==
Splitting Attraction: A History of Discussing Orientation by Aromantic-spectrum Union for Recognition, Education, and Advocacy (AUREA) | Wikipedia/Split_attraction_model |
Calendar-based methods are various methods of estimating a woman's likelihood of fertility, based on a record of the length of previous menstrual cycles. Various methods are known as the Knaus–Ogino method and the rhythm method. The standard days method is also considered a calendar-based method, because when using it, a woman tracks the days of her menstrual cycle without observing her physical fertility signs. The standard days method is based on a fixed formula taking into consideration the timing of ovulation, the functional life of the sperm and the ovum, and the resulting likelihood of pregnancy on particular days of the menstrual cycle. These methods may be used to achieve pregnancy by timing unprotected intercourse for days identified as fertile, or to avoid pregnancy by avoiding unprotected intercourse during fertile days.
The first formalized calendar-based method was developed in 1930 by John Smulders, a Catholic physician from the Netherlands. It was based on knowledge of the menstrual cycle. This method was independently discovered by Hermann Knaus (Austria), and Kyusaku Ogino (Japan). This system was a main form of birth control available to Catholic couples for several decades, until the popularization of symptoms-based fertility awareness methods. A new development in calendar-based methods occurred in 2002, when Georgetown University introduced the Standard Days Method. The Standard Days Method is promoted in conjunction with a product called CycleBeads, a ring of colored beads which are meant to help the user keep track of her fertile and non-fertile days.
== Terminology ==
While the terms rhythm method and fertility awareness are not synonymous, some sources do treat them as such. However, fertility awareness is usually used as a broad term that includes tracking basal body temperature and cervical mucus as well as cycle length. The World Health Organization considers the rhythm method to be a specific type of calendar-based method, and calendar-based methods to be only one form of fertility awareness.
More effective than calendar-based methods, systems of fertility awareness that track basal body temperature, cervical mucus, or both, are known as symptoms-based methods. Teachers of symptoms-based methods take care to distance their systems from the poor reputation of the rhythm method. Many consider the rhythm method to have been obsolete for at least 20 years, and some even exclude calendar-based methods from their definition of fertility awareness.
Some sources may treat the terms rhythm method and natural family planning as synonymous. In the early 20th century, the calendar-based method known as the rhythm method was promoted by members of the Roman Catholic Church as the only morally acceptable form of family planning. Methods accepted by this church are referred to as natural family planning (NFP): so at one time, the term "the rhythm method" was synonymous with NFP. Today, NFP is an umbrella term that includes symptoms-based fertility awareness methods and the lactational amenorrhea method as well as calendar-based methods such as rhythm. This overlap between uses of the terms "the rhythm method" and "natural family planning" may contribute to confusion.
The first day of bleeding is considered day one of the menstrual cycle.
== History ==
=== Early methods ===
It is not known if historical cultures were aware of what part of the menstrual cycle is most fertile. In the year 388, Augustine of Hippo wrote of periodic abstinence. Addressing followers of Manichaeism, his former religion, he said, "Is it not you who used to counsel us to observe as much as possible the time when a woman, after her purification, is most likely to conceive, and to abstain from cohabitation at that time...?" If the Manichaieans practiced something like the Jewish observances of menstruation, then the "time... after her purification" would have indeed been when "a woman... is most likely to conceive." Over a century previously, however, the influential Greek physician Soranus had written that "the time directly before and after menstruation" was the most fertile part of a woman's cycle; this inaccuracy was repeated in the 6th century by the Byzantine physician Aëtius. Similarly, a Chinese sex manual written close to the year 600 stated that only the first five days following menstruation were fertile. Some historians believe that Augustine, too, incorrectly identified the days immediately after menstruation as the time of highest fertility.
Written references to a "safe period" do not appear again for over a thousand years. Scientific advances prompted a number of secular thinkers to advocate periodic abstinence to avoid pregnancy: in the 1840s it was discovered that many animals ovulate during estrus. Because some animals (such as dogs) have a bloody discharge during estrus, it was assumed that menstruation was the corresponding most fertile time for women. This inaccurate theory was popularized by physicians Bischoff, Félix Archimède Pouchet, and Adam Raciborski. In 1854, an English physician named George Drysdale correctly taught his patients that the days near menstruation are the least fertile, but this remained the minority view for the remainder of the 19th century.
=== Knaus–Ogino or rhythm method ===
In 1905 Theodoor Hendrik van de Velde, a Dutch gynecologist, showed that women only ovulate once per menstrual cycle. In the 1920s, Kyusaku Ogino, a Japanese gynecologist, and Hermann Knaus, from Austria, working independently, each made the discovery that ovulation occurs about fourteen days before the next menstrual period. Ogino used his discovery to develop a formula for use in aiding infertile women to time intercourse to achieve pregnancy.
In 1930, Johannes Smulders, a Roman Catholic physician from the Netherlands, used Knaus and Ogino's discoveries to create a method for avoiding pregnancy. Smulders published his work with the Dutch Roman Catholic medical association, and this was the official rhythm method promoted over the next several decades. In 1932 a Catholic physician, Dr. Leo J Latz, published a book titled The Rhythm of Sterility and Fertility in Women describing the method, and the 1930s also saw the first U.S. Rhythm Clinic (founded by John Rock) to teach the method to Catholic couples.
=== Later 20th century to present ===
In the first half of the 20th century, most users of the rhythm method were Catholic; they were following their church's teaching that all other methods of birth control were sinful. In 1968 the encyclical Humanae vitae included the statement, "It is supremely desirable... that medical science should by the study of natural rhythms succeed in determining a sufficiently secure basis for the chaste limitation of offspring." This is interpreted as favoring the then-new, more reliable symptoms-based fertility awareness methods over the rhythm method. Currently, many fertility awareness teachers consider the rhythm method to have been obsolete for at least 20 years.
New attention was drawn to calendar-based methods in 2002, when the Institute for Reproductive Health at Georgetown University introduced the Standard Days Method. Designed to be simpler to teach and use than the older rhythm method, the Standard Days Method was initially integrated piloted in 30 family planning programs worldwide. However, only 16 countries scaled up beyond pilots, with limited adoption since.
== Types and effectiveness ==
Most menstrual cycles have several days at the beginning that are infertile (pre-ovulatory infertility), a period of fertility, and then several days just before the next menstruation that are infertile (post-ovulatory infertility). The first day of red bleeding is considered day one of the menstrual cycle. To use these methods, a woman is required to know the length of her menstrual cycles.
Imperfect use of calendar-based methods would consist of not correctly tracking the length of the woman's cycles, thus using the wrong numbers in the formula, or of having unprotected intercourse on an identified fertile day. The discipline required to keep accurate records of menstrual cycles, and to abstain from unprotected intercourse, makes imperfect use fairly common. The typical-use failure rate of calendar-based methods is 25% per year.
=== Rhythm method (Knaus–Ogino method) ===
To find the estimated length of the pre-ovulatory infertile phase, eighteen (18) is subtracted from the length of the woman's shortest cycle. To find the estimated start of the post-ovulatory infertile phase, eleven (11) is subtracted from the length of the woman's longest cycle. A woman whose menstrual cycles ranged in length from 30 to 36 days would be estimated to be infertile for the first 11 days of her cycle (30-19=11), to be fertile on days 12–25, and to resume infertility on day 26 (36-10=26). When used to avoid pregnancy, such fertility awareness-based methods have a typical-use failure rate of 25% per year.
=== Standard days method ===
Developed at Georgetown University's Institute for Reproductive Health, the standard days method is a variation of the rhythm method that has a simpler rule set and is more effective than the Knaus–Ogino method. A product called CycleBeads was developed alongside the method to help the user keep track of estimated high and low fertility points during her menstrual cycle. The standard days method is only effective for women whose cycles are consistently between 26 and 32 days in length; it is estimated that between 50% and 60% of women of reproductive age satisfy this condition. In this system:
Days 1–7 of a woman's menstrual cycle are considered infertile
Days 8–19 are considered fertile; considered unsafe for unprotected intercourse
Day 20 through the end of the cycle are considered infertile.
When used to avoid pregnancy, the standard days method has been estimated to have perfect-use efficacy of 95% and typical-use efficacy of 88%. These figures are based on a 2002 study in Bolivia, Peru, and the Philippines of women of reproductive age having menstrual cycles between 26 and 32 days,: 505 and on a 2014 study in Turkey. However, other researchers have criticized the methodology of the first study, have stated that the 95% figure has been presented to the public in misleading ways, and have argued that the true efficacy figures are likely to be much lower. Another meta study indicated that typical-use efficacy ranged between 90% and 82%, a bit lower than the 88% figure originally found.
== Software-based systems ==
Several web-based implementations of the cycle method exist, as well as mobile apps such as Natural Cycles.
== Advantages ==
The Standard Days method (SDM) was introduced as part of family planning programs in developing countries. The method is satisfactory for many women and men. The low cost of the method may also enable it to play a useful role in countries that lack funding to provide other methods of birth control.
== Potential concerns ==
=== Failure rate ===
One concern related to the use of calendar-based methods is their relatively high failure rate, compared to other methods of birth control. Even when used perfectly, calendar-based methods, especially the rhythm method, result in a high pregnancy rate among couples intending to avoid pregnancy. Of commonly known methods of birth control, only the cervical cap and contraceptive sponge have comparably high failure rates. This lower level of reliability of calendar-based methods is because their formulas make several assumptions that are not always true.
The postovulatory (luteal) phase has a normal length of 12 to 16 days, and the rhythm method formula assumes all women have luteal phase lengths within this range. However, many women have shorter luteal phases, and a few have longer luteal phases. For these women, the rhythm method formula incorrectly identifies a few fertile days as being in the infertile period. Roughly 30-50% of women have phases outside this range.
Finally, calendar-based methods assume that all bleeding is true menstruation. However, mid-cycle or anovulatory bleeding can be caused by a number of factors. Incorrectly identifying bleeding as menstruation will cause the method's calculations to be incorrect.
=== Embryonic health ===
It has been suggested that pregnancies resulting from failures of periodic abstinence methods are at increased risk of miscarriage and birth defects due to aged gametes at the time of conception. Other research suggests that timing of conception has no effect on miscarriage rates, low birth weight, or preterm delivery.
=== Destruction of fertilized eggs ===
Philosopher Luc Bovens has suggested that the use of the rhythm method probably results in a large number of abortions, because unprotected intercourse in the infertile periods of the menstrual cycle may still result in conceptions but create zygotes incapable of implanting. Bovens's argument assumes that any and all destruction of fertilized eggs is abortion.
== References == | Wikipedia/Calendar-based_contraceptive_methods |
Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original hormonal method—the combined oral contraceptive pill—was first marketed as a contraceptive in 1960. In the ensuing decades, many other delivery methods have been developed, although the oral and injectable methods are by far the most popular. Hormonal contraception is highly effective: when taken on the prescribed schedule, users of steroid hormone methods experience pregnancy rates of less than 1% per year. Perfect-use pregnancy rates for most hormonal contraceptives are usually around the 0.3% rate or less. Currently available methods can only be used by women; the development of a male hormonal contraceptive is an active research area.
There are two main types of hormonal contraceptive formulations: combined methods which contain both an estrogen and a progestin, and progestogen-only methods which contain only progesterone or one of its synthetic analogues (progestins). Combined methods work by suppressing ovulation and thickening cervical mucus; while progestogen-only methods reduce the frequency of ovulation, most of them rely more heavily on changes in cervical mucus. The incidence of certain side effects is different for the different formulations: for example, breakthrough bleeding is much more common with progestogen-only methods. Certain serious complications occasionally caused by estrogen-containing contraceptives are not believed to be caused by progestogen-only formulations: deep vein thrombosis is one example of this.
== Medical uses ==
Hormonal contraception is primarily used for the prevention of pregnancy, but is also prescribed for the treatment of polycystic ovary syndrome, menstrual disorders such as dysmenorrhea and menorrhagia, and hirsutism.
=== Polycystic ovary syndrome ===
Hormonal treatments, such as hormonal contraceptives, are frequently successful at alleviating symptoms associated with polycystic ovary syndrome. Birth control pills are often prescribed to reverse the effects of excessive androgen levels, and decrease ovarian hormone production.
=== Dysmenorrhea ===
Hormonal birth control methods such as birth control pills, the contraceptive patch, vaginal ring, contraceptive implant, and hormonal IUD are used to treat cramping and pain associated with primary dysmenorrhea.
=== Menorrhagia ===
Oral contraceptives are prescribed in the treatment of menorrhagia to help regulate menstrual cycles and prevent prolonged menstrual bleeding. The hormonal IUD (Mirena) releases levonorgestrel which thins the uterine lining, preventing excessive bleeding and loss of iron.
=== Hirsutism ===
Birth control pills are the most commonly prescribed hormonal treatment for hirsutism, as they prevent ovulation and decrease androgen production by the ovaries. Additionally, estrogen in the pills stimulates the liver to produce more of a protein that binds to androgens and reduces their activity.
=== Effectiveness ===
Modern contraceptives using steroid hormones have perfect-use or method failure rates of less than 1% per year. The lowest failure rates are seen with the implants Jadelle and Implanon, at 0.05% per year. According to Contraceptive Technology, none of these methods has a failure rate greater than 0.3% per year. The SERM ormeloxifene is less effective than the steroid hormone methods; studies have found a perfect-use failure rate near 2% per year.
Long-acting methods such as the implant and the IUS are user-independent methods. For user-independent methods, the typical or actual-use failure rates are the same as the method failure rates. Methods that require regular action by the user—such as taking a pill every day—have typical failure rates higher than perfect-use failure rates. Contraceptive Technology reports a typical failure rate of 3% per year for the injection Depo-Provera, and 8% per year for most other user-dependent hormonal methods. While no large studies have been done, it is hoped that newer methods which require less frequent action (such as the patch) will result in higher user compliance and therefore lower typical failure rates.
Currently there is little evidence that there is an association between being overweight and the effectiveness of hormonal contraceptives.
=== Combined vs. progestogen-only ===
While unpredictable breakthrough bleeding is a possible side effect for all hormonal contraceptives, it is more common with progestogen-only formulations. Most regimens of COCPs, NuvaRing, and the contraceptive patch incorporate a placebo or break week that causes regular withdrawal bleeding. While women using combined injectable contraceptives may experience amenorrhea (lack of periods), they typically have predictable bleeding comparable to that of women using COCPs.
Although high-quality studies are lacking, it is believed that estrogen-containing contraceptives significantly decrease the quantity of milk in breastfeeding women. Progestogen-only contraceptives are not believed to have this effect. In addition, while in general the progestogen-only pill is less effective than other hormonal contraceptives, the added contraceptive effect of breastfeeding makes it highly effective in breastfeeding women.
While combined contraceptives increase the risk for deep vein thrombosis (DVT – blood clots), progestogen-only contraceptives are not believed to affect DVT formation.
== Side effects ==
=== Cancers ===
There is a mixed effect of combined hormonal contraceptives on the rates of various cancers, with the International Agency for Research on Cancer (IARC) stating: "It was concluded that, if the reported association was causal, the excess risk for breast cancer associated with typical patterns of current use of combined oral contraceptives was very small." and also saying that "there is also conclusive evidence that these agents have a protective effect against cancers of the ovary and endometrium":
The (IARC) notes that "the weight of the evidence suggests a small increase in the relative risk for breast cancer among current and recent users" which following discontinuation then lessens over a period of 10 years to similar rates as women who never used them, as well as "The increase in risk for breast cancer associated with the use of combined oral contraceptives in younger women could be due to more frequent contacts with doctors"
Small increases are also seen in the rates of cervical cancer and hepatocellular (liver) tumours.
Endometrial and ovarian cancer risks are approximately halved and persists for at least 10 years after cessation of use; although "sequential oral contraceptives which were removed from the consumer market in the 1970s was associated with an increased risk for endometrial cancer".
Studies have overall not shown effects on the relative risks for colorectal, malignant melanoma or thyroid cancers.
Information on progesterone-only pills is less extensive, due to smaller sampling sizes, but they do not appear to significantly increase the risk of breast cancer.
Most other forms of hormonal contraception are too new for meaningful data to be available, although risks and benefits are believed to be similar for methods which use the same hormones; e.g., risks for combined-hormone patches are thought to be roughly equivalent to those for combined-hormone pills.
=== Cardiovascular disease ===
Combined oral contraceptives can increase the risk of certain types of cardiovascular disease in women with a pre-existing condition or already-heightened risk of cardiovascular disease. Smoking (for women over 35), metabolic conditions like diabetes, obesity and family history of heart disease are all risk factors which may be exacerbated by the use of certain hormonal contraceptives. Oral contraceptives have also been linked to an inflated risk of myocardial infarction, arterial thrombosis, and ischemic stroke.
=== Blood clots ===
Hormonal contraception methods are consistently linked with the risk of developing blood clots. However, the risk does vary depending on the hormone type or birth control method being used.
== Types ==
There are two main classes of hormonal contraceptives: combined contraceptives contain both an estrogen and a progestin, and progestogen-only contraceptives that contain only progesterone or a synthetic analogue (progestin). There is also a non-hormonal contraceptive called ormeloxifene which acts on the hormonal system to prevent pregnancy.
=== Combined ===
The most popular form of hormonal contraception, is the combined oral contraceptive pill (COCP) known colloquially as the pill. It is taken once a day, most commonly for 21 days followed by a seven-day break, although other regimens are also used. For women not using ongoing hormonal contraception, COCPs may be taken after intercourse as emergency contraception: this is known as the Yuzpe regimen. COCPs are available in a variety of formulations.
The contraceptive patch is applied to the skin and worn continuously. A series of three patches are worn for one week each, and then the user takes a one-week break. NuvaRing is worn inside the vagina. A ring is worn for three weeks. After removal, the user takes a one-week break before inserting a new ring. As with COCPs, other regimens may be used with the contraceptive patch or NuvaRing to provide extended cycle combined hormonal contraception.
Some combined injectable contraceptives can be administered as one injection per month.
=== Progestogen-only ===
The progestogen-only pill (POP) is taken once per day within the same three-hour window. Several different formulations of POP are marketed. A low-dose formulation is known as the minipill. Unlike COCPs, progestogen-only pills are taken every day with no breaks or placebos. For women not using ongoing hormonal contraception, progestogen-only pills may be taken after intercourse as emergency contraception. There are a number of dedicated products sold for this purpose.
Hormonal intrauterine contraceptives are known as intrauterine systems (IUS) or Intrauterine Devices (IUD). An IUS/IUD must be inserted by a health professional. The copper IUD does not contain hormones. While a copper-containing IUD may be used as emergency contraception, the IUS has not been studied for this purpose.
Depo-Provera is an injection that provides three months of contraceptive protection. Noristerat is another injection; it is given every two months.
Contraceptive implants are inserted under the skin of the upper arm, and contain progesterone only. Jadelle (Norplant 2) consists of two rods that release a low dose of hormones. It is effective for five years. Nexplanon has replaced the former Implanon and is also a single rod that releases etonogestrel (similar to the body's natural progesterone). The only difference between Implanon and Nexplanon is Nexplanon is radio opaque and can be detected by x-ray. This is needed for cases of implant migration. It is effective for three years and is usually done in office. It is over 99% effective. It works in 3 ways:
1. Prevents ovulation- usually an egg does not mature
2. thickens cervical mucus so to prevent sperm from reaching the egg
3. If those 2 fail, the last is the progesterone causes the lining of the uterus to be too thin for implantation.
=== Ormeloxifene ===
Ormeloxifene is a selective estrogen receptor modulator (SERM). Marketed as Centchroman, Centron, or Saheli, it is pill that is taken once per week. Ormeloxifene is legally available only in India.
== Mechanism of action ==
The effect of hormonal agents on the reproductive system is complex. It is believed that combined hormonal contraceptives work primarily by preventing ovulation and thickening cervical mucus. Progestogen-only contraceptives can also prevent ovulation, but rely more significantly on the thickening of cervical mucus. Ormeloxifene does not affect ovulation, and its mechanism of action is not well understood.
=== Combined ===
Combined hormonal contraceptives were developed to prevent ovulation by suppressing the release of gonadotropins. They inhibit follicular development and prevent ovulation as a primary mechanism of action.
Progestogen negative feedback decreases the pulse frequency of gonadotropin-releasing hormone (GnRH) release by the hypothalamus, which decreases the release of follicle-stimulating hormone (FSH) and greatly decreases the release of luteinizing hormone (LH) by the anterior pituitary. Decreased levels of FSH inhibit follicular development, preventing an increase in estradiol levels. Progestogen negative feedback and the lack of estrogen positive feedback on LH release prevent a mid-cycle LH surge. Inhibition of follicular development and the absence of a LH surge prevent ovulation.
Estrogen was originally included in oral contraceptives for better cycle control (to stabilize the endometrium and thereby reduce the incidence of breakthrough bleeding), but was also found to inhibit follicular development and help prevent ovulation. Estrogen negative feedback on the anterior pituitary greatly decreases the release of FSH, which inhibits follicular development and helps prevent ovulation.
Another primary mechanism of action of all progestogen-containing contraceptives is inhibition of sperm penetration through the cervix into the upper genital tract (uterus and fallopian tubes) by decreasing the amount of and increasing the viscosity of the cervical mucus.
The estrogen and progestogen in combined hormonal contraceptives have other effects on the reproductive system, but these have not been shown to contribute to their contraceptive efficacy:
Slowing tubal motility and ova transport, which may interfere with fertilization.
Endometrial atrophy and alteration of metalloproteinase content, which may impede sperm motility and viability, or theoretically inhibit implantation.
Endometrial edema, which may affect implantation.
Insufficient evidence exists on whether changes in the endometrium could actually prevent implantation. The primary mechanisms of action are so effective that the possibility of fertilization during combined hormonal contraceptive use is very small. Since pregnancy occurs despite endometrial changes when the primary mechanisms of action fail, endometrial changes are unlikely to play a significant role, if any, in the observed effectiveness of combined hormonal contraceptives.
=== Progestogen-only ===
The mechanism of action of progestogen-only contraceptives depends on the progestogen activity and dose.
Low dose progestogen-only contraceptives include traditional progestogen-only pills, the subdermal implant Jadelle and the intrauterine system Mirena. These contraceptives inconsistently inhibit ovulation in ~50% of cycles and rely mainly on their progestogenic effect of thickening the cervical mucus and thereby reducing sperm viability and penetration.
Intermediate dose progestogen-only contraceptives, such as the progestogen-only pill Cerazette (or the subdermal implant Implanon), allow some follicular development but much more consistently inhibit ovulation in 97–99% of cycles. The same cervical mucus changes occur as with low dose progestogens.
High dose progestogen-only contraceptives, such as the injectables Depo-Provera and Noristerat, completely inhibit follicular development and ovulation. The same cervical mucus changes occur as with very low dose and intermediate dose progestogens.
In anovulatory cycles using progestogen-only contraceptives, the endometrium is thin and atrophic. If the endometrium was also thin and atrophic during an ovulatory cycle, this could theoretically interfere with implantation of a blastocyst (embryo).
=== Ormeloxifene ===
Ormeloxifene does not affect ovulation. It has been shown to increase the rate of blastocyst development and to increase the speed at which the blastocyst is moved from the fallopian tubes into the uterus. Ormeloxifene also suppresses proliferation and decidualization of the endometrium (the transformation of the endometrium in preparation for possible implantation of an embryo). While they are believed to prevent implantation rather than fertilization, exactly how these effects operate to prevent pregnancy is not understood
== Emergency contraception ==
The use of emergency contraceptives (ECs) allows for the prevention of a pregnancy after unprotected sex or contraception failure. In the United States, there are currently four different methods available, including ulipristal acetate (UPA), an oral progesterone receptor agonist-antagonist; levonorgestrel (LNG), an oral progestin; off-label use of combined oral contraceptives (Yuzpe regimen); and the copper intrauterine device (Cu-IUD).
=== Types ===
UPA, a progesterone agonist-antagonist, was approved by the FDA in 2010 for use as an EC. UPA acts as a partial agonist and antagonist of the progesterone receptor and works by preventing both ovulation and fertilization. Users of UPA are likely to experience delayed menses after the expected date. In the United States, UPA is sold under the brand name Ella, which is a 30 mg single pill to be taken up to 120 hours after unprotected sex. /> UPA has emerged as the most effective EC pill, however, the access to UPA is very limited in US cities. UPA is a prescription emergency contraceptive pill and a recent study has found that less than 10% of pharmacies indicated that a UPA prescription could be filled immediately. 72% of pharmacies reported the ability to order UPA and the prescription to be filled in a median wait time of 24 hours.
Plan B one step was the first levonorgestrel progestin-only EC approved by the FDA in 1999. Currently, there are many different brands of levonorgestrel EC pills, including Take Action, Next Choice One Dose, and My Way and regimens include a single 1.5 mg pill of levonorgestrel. Levonorgestrel EC pills should be taken up to 72 hours after unprotected sex due to the drug becoming less effective over time. Levonorgestrel acts as an agonist of the progesterone receptor, preventing ovulation. Users of levonorgestrel often experience menses before the expected date. A prescription for levonorgestrel is not needed and can be found over the counter at local pharmacies. Because levonorgestrel does not have any life-threatening side effects, it has been approved by the FDA for use by all age groups.
The Yuzpe regimen used combination oral contraceptives for EC and has been used since 1974. This regimen is no longer commonly used due to side effects such as nausea and vomiting, as well as the discovery of more effective methods. The regimen consists of two pills, each containing a minimum 100 μg of ethinyl estradiol and a minimum of 500 μg of levonorgestrel. The first pill is taken 72 hours after unprotected sex and the second pill is taken 12 hours after the first. The Yuzpe regimen is often used in areas where dedicated EC methods are unavailable or where EC is not accepted.
The most effective form of EC is the insertion of a Cu-IUD within 5 days of unprotected sex. Because the Cu-IUD is inserted into the uterus, it has the advantage of providing continued contraception for up to 10 years. Cu-IUDs have been the only IUDs that have been approved as ECs due to the mechanism in hormonal and copper IUDs differing. Hormonal IUDs are used for the treatment of unplanned pregnancies by being placed in the uterus after an oral EC has been taken.
== Frequency of use ==
Pills—combined and progestogen-only—are the most common form of hormonal contraception. Worldwide, they account for 12% of contraceptive use. 21% of users of reversible contraceptives choose COCPs or POPs. Pills are especially popular in more developed countries, where they account for 25% of contraceptive use.
Injectable hormonal contraceptives are also used by a significant portion—about 6%—of the world's contraceptive users. Other hormonal contraceptives are less common, accounting for less than 1% of contraceptive use.
== History ==
In 1921, Ludwig Haberlandt demonstrated a temporary hormonal contraception in a female rabbit by transplanting ovaries from a second, pregnant, animal. By the 1930s, scientists had isolated and determined the structure of the steroid hormones and found that high doses of androgens, estrogens, or progesterone inhibited ovulation. A number of economic, technological, and social obstacles had to be overcome before the development of the first hormonal contraceptive, the combined oral contraceptive pill (COCP). In 1957 Enovid, the first COCP, was approved in the United States for the treatment of menstrual disorders. In 1960, the U.S. Food and Drug Administration approved an application that allowed Enovid to be marketed as a contraceptive.
The first progestogen-only contraceptive was introduced in 1969: Depo-Provera, a high-dose progestin injection. Over the next decade and a half, other types of progestogen-only contraceptive were developed: a low-dose progestogen only pill (1973); Progestasert, the first hormonal intrauterine device (1976); and Norplant, the first contraceptive implant (1983).
Combined contraceptives have also been made available in a variety of forms. In the 1960s a few combined injectable contraceptives were introduced, notably Injectable Number 1 in China and Deladroxate in Latin America. A third combined injection, Cyclo-Provera, was reformulated in the 1980s by lowering the dose and renamed Cyclofem (also called Lunelle). Cyclofem and Mesigyna, another formulation developed in the 1980s, were approved by the World Health Organization in 1993. NuvaRing, a contraceptive vaginal ring, was first marketed in 2002. 2002 also saw the launch of Ortho Evra, the first contraceptive patch.
In 1991, ormeloxifene was introduced as a contraceptive in India. While it acts on the estrogen hormonal system, it is atypical in that it is a selective estrogen receptor modulator rather than an estrogen, and has the capacity for both estrogenic and antiestrogenic effects.
== See also ==
Reproductive Health Supplies Coalition
Male hormonal contraception
Progestogen-only injectable contraceptive
Estradiol-containing oral contraceptive
List of progestogens available in the United States
List of estrogens available in the United States
== References ==
== External links ==
Media related to Hormonal contraception at Wikimedia Commons | Wikipedia/Hormonal_birth_control |
A reproductive system disease is any disease of the human reproductive system.
== Types ==
=== Infections ===
Reproductive tract infection (RTI) are infections that affect the reproductive tract, which is part of the reproductive system. For females, reproductive tract infections can affect the upper reproductive tract (fallopian tubes, ovary and uterus) and the lower reproductive tract (vagina, cervix and vulva); for males these infections affect the penis, testicles, urethra or the vas deferens. The three types of reproductive tract infections are endogenous infections, iatrogenic infections and the more commonly known sexually transmitted infections. Each has its own specific causes and symptoms, caused by a bacterium, virus, fungus or other organism. Some infections are easily treatable and can be cured, some are more difficult, and some are non curable such as AIDS and herpes.
=== Congenital abnormalities ===
Examples of congenital abnormalities of the reproductive system include:
Kallmann syndrome - Genetic disorder causing decreased functioning of the sex hormone-producing glands caused by a deficiency of one or both testes from the scrotum.
Androgen insensitivity syndrome - A genetic disorder causing people who are genetically male (i.e. XY chromosome pair) to develop sexually as a female due to an inability to utilize androgen.
Intersexuality - A person who has genitalia and/or other sexual traits which are not clearly male or female.
=== Examples of cancers ===
Examples of cancers of the reproductive system include:
Benign prostatic hyperplasia
Breast cancer - Cancer of the mammary gland
Cervical cancer - Cancer of the cervix
Ovarian cancer - Cancer of the ovary
Penile cancer - Cancer of the penis
Prostate cancer - Cancer of the prostate gland
Uterine cancer - Cancer of the uterus
Testicular cancer - Cancer of the testicle
Vulvar cancer - Cancer of the vulva
=== Examples of functional problems ===
Examples of functional problems of the reproductive system include:
Impotence - The inability of a male to produce or maintain an erection.
Hypogonadism - A lack of function of the gonads, in regards to either hormones or gamete production.
Ectopic pregnancy - When a fertilized ovum is implanted in any tissue other than the uterine wall.
Female sexual arousal disorder - A condition of decreased, insufficient, or absent lubrication in females during sexual activity
Premature ejaculation - A lack of voluntary control over ejaculation.
Dysmenorrhea - Is a medical condition of pain during menstruation that interferes with daily activities
=== Endocrine ===
It is also known that disruption of the endocrine system by certain chemicals adversely affects the development of the reproductive system and can cause vaginal cancer. Many other reproductive diseases have also been link to exposure to synthetic and environmental chemicals. Common chemicals with known links to reproductive disorders include: lead, dioxins and dioxin-like compounds, styrene, toluene, BPA (Bisphenol A) and pesticides.
== References == | Wikipedia/Reproductive_system_disease |
Safe sex is sexual activity using methods or contraceptive devices (such as condoms) to reduce the risk of transmitting or acquiring sexually transmitted infections (STIs), especially HIV. "Safe sex" is also sometimes referred to as safer sex or protected sex to indicate that some safe sex practices do not eliminate STI risks. It is also sometimes used colloquially to describe methods aimed at preventing pregnancy that may or may not also lower STI risks.
The concept of "safe sex" emerged in the 1980s as a response to the global AIDS epidemic, and possibly more specifically to the AIDS crisis in the United States. Promoting safe sex is now one of the main aims of sex education and STI prevention, especially reducing new HIV infections. Safe sex is regarded as a harm reduction strategy aimed at reducing the risk of STI transmission.
Although some safe sex practices (like condoms) can also be used as birth control (contraception), most forms of contraception do not protect against STIs. Likewise, some safe sex practices, such as partner selection and low-risk sex behavior, might not be effective forms of contraception.
== History ==
Although strategies for avoiding STIs like syphilis and gonorrhea have existed for centuries and the term "safe sex" existed in English as early as the 1930s, the use of the term to refer to STI-risk reduction dates to the mid-1980s in the United States. It emerged in response to the HIV/AIDS crisis.
A year before the HIV virus was isolated and named, the San Francisco chapter of the Sisters of Perpetual Indulgence published a small pamphlet titled Play Fair! out of concern over widespread STIs among the city's gay male population. It specifically named illnesses (Kaposi's sarcoma and pneumocystis pneumonia) that would later be understood as symptoms of advanced HIV disease (or AIDS). The pamphlet advocated a range of safe-sex practices, including abstinence, condoms, personal hygiene, use of personal lubricants, and STI testing/treatment. It took a casual, sex-positive approach while also emphasizing personal and social responsibility. In May 1983—the same month HIV was isolated and named in France—the New York City-based HIV/AIDS activists Richard Berkowitz and Michael Callen published similar advice in their booklet, How to Have Sex in an Epidemic: One Approach. Both publications included recommendations that are now standard advice for reducing STI (including HIV) risks.
Safe sex as a form of STI risk reduction appeared in journalism as early as 1984, in the British publication The Daily Intelligencer: "The goal is to reach about 50 million people with messages about safe sex and AIDS education."
Although safe sex is used by individuals to refer to protection against both pregnancy and HIV/AIDS or other STI transmissions, the term was born in response to the HIV/AIDS epidemic. It is believed that the term safe sex was used in the professional literature in 1984, in the content of a paper on the psychological effect that HIV/AIDS may have on gay and bisexual men.
A year later, the same term appeared in an article in The New York Times. This article emphasized that most specialists advised their AIDS patients to practice safe sex. The concept included limiting the number of sexual partners, using prophylactics, avoiding bodily fluid exchange, and resisting the use of drugs that reduced inhibitions for high-risk sexual behavior. Moreover, in 1985, the first safe sex guidelines were established by the 'Coalition for Sexual Responsibilities'. According to these guidelines, safe sex was practiced by using condoms also when engaging in anal or oral sex.
Although the term safe sex was primarily used in reference to sexual activity between men, in 1986 the concept was spread to the general population. Various programs were developed with the aim of promoting safe sex practices among college students. These programs were focused on promoting the use of the condom, a better knowledge about the partner's sexual history and limiting the number of sexual partners. The first book on this subject appeared in the same year. The book was entitled "Safe Sex in the Age of AIDS", and had 88 pages that described both positive and negative approaches to sexual life. Sexual behavior could be safe (kissing, hugging, massage, body-to-body rubbing, mutual masturbation, exhibitionism, phone sex, and use of separate sex toys); possibly safe (use of condoms); or unsafe.
In 1997, specialists in this matter promoted the use of condoms as the most accessible safe sex method (besides abstinence) and they called for TV commercials featuring condoms. During the same year, the Catholic Church in the United States issued their own "safer sex" guidelines on which condoms were listed, though two years later the Vatican urged chastity and heterosexual marriage, attacking the American Catholic bishops' guidelines.
A study carried out in 2006 by Californian specialists showed that the most common definitions of safe sex are condom use (68% of the interviewed subjects), abstinence (31.1% of the interviewed subjects), monogamy (28.4% of the interviewed subjects) and safe partner (18.7% of the interviewed subjects).
The term safer sex in Canada and the United States has gained greater use by health workers, reflecting that risk of transmission of sexually transmitted infections in various sexual activities is a continuum. The term safe sex is still in common use in the United Kingdom, Australia and New Zealand.
"Safer sex" is thought to be a more aggressive term which may make it more obvious to individuals that any type of sexual activity carries a certain degree of risk.
The term safe love has also been used, notably by the French Sidaction in the promotion of men's underpants incorporating a condom pocket and including the red ribbon symbol in the design, which were sold to support the charity.
== Practices ==
A range of safe-sex practices are commonly recommended by Sexual Health Educators and Public Health Agencies. Many of these practices can reduce (but not eliminate) risk of transmitting or acquiring STIs.
=== Phone sex/cybersex/sexting ===
Sexual activities, such as phone sex, cybersex, and sexting, that do not include direct contact with the skin or bodily fluids of sexual partners, carry no STI risks and, thus, are forms of safe sex.
=== Non-penetrative sex ===
A range of sex acts called "non-penetrative sex" or "outercourse" can significantly reduce STI risks. Non-penetrative sex includes practices such as kissing, mutual masturbation, manual sex, rubbing or stroking. According to the Health Department of Western Australia, this sexual practice may prevent pregnancy and most STIs. However, non-penetrative sex may not protect against infections that can be transmitted via skin-to-skin contact, such as herpes and human papilloma virus. Mutual masturbation and manual sex carry some STI risk, especially if there is skin contact or shared bodily fluids with sexual partners, although the risks are significantly lower than other sexual activities.
=== Condoms, dental dams, gloves ===
Barriers, such as condoms, dental dams, and medical gloves can prevent contact with body fluids (such as blood, vaginal fluid, semen, rectal mucus), and other means of transmitting STIs (like skin, hair and shared objects) during sexual activity.
External condoms can be used to cover the penis, hands, fingers, or other body parts during sexual penetration or oral sex. They are most frequently made of latex, and can also be made out of synthetic materials including polyurethane and polyisoprene.
Internal condoms (also called female condoms) are inserted into the vagina or anus prior to sexual penetration. These condoms are made of either polyurethane or nitrile. If external and internal condoms are used at the same time, they may break due to friction between the materials during sexual activity.
A dental dam (originally used in dentistry) is a sheet of latex typically used for protection between the mouth and the vulva or anus when engaging in oral sex.
Medical gloves and finger cots made out of latex, vinyl, nitrile, or polyurethane can cover hands or fingers during manual sex or may be used as a makeshift dental dam during oral sex.
Condoms, dental dams, and gloves can also be used to cover sex toys such as dildos during sexual stimulation or penetration. If a sex toy is to be used in more than one orifice or partner, a condom/dental dam/glove can be used over it and changed when the toy is moved.
Oil-based lubrication can break down the structure of latex condoms, dental dams or gloves, reducing their effectiveness for STI protection.
While use of external condoms can reduce STI risks during sexual activity, they are not 100% effective. One study has suggested condoms might reduce HIV transmission by 85% to 95%; effectiveness beyond 95% was deemed unlikely because of slippage, breakage, and incorrect use. It also said, "In practice, inconsistent use may reduce the overall effectiveness of condoms to as low as 60–70%".p. 40.
=== Pre-exposure prophylaxis (PrEP) ===
Pre-exposure prophylaxis (often abbreviated as PrEP) is the use of prescription drugs by those who do not have HIV to prevent HIV infection. PrEP drugs are taken prior to HIV exposure to prevent the transmission of the virus, usually between sexual partners. PrEP drugs do not prevent other STI infections or pregnancy.
As of 2018, the most-widely approved form of PrEP combines two drugs (tenofovir and emtricitabine) in one pill. That drug combination is sold under the brand name Truvada by Gilead Sciences. It is also sold in generic formulations worldwide. Other drugs and modalities are being studied for use as PrEP.
Different countries have approved different protocols for using the tenofovir/emtricitabine-combination drug as PrEP. That two-drug combination has been shown to prevent HIV infection in different populations when taken daily, intermittently, and on demand. Numerous studies have found the tenofovir/emtricitabine combination to be over 90% effective at preventing HIV transmission between sexual partners. AVAC has developed a tool to track trends in PrEP uptake across the globe.
=== Treatment as prevention ===
Treatment as Prevention (often abbreviated as TasP) is the practice of testing for and treating HIV infection as a way to prevent further spread of the virus. Those having knowledge of their HIV-positive status can use safe-sex practices to protect themselves and their partners (such as using condoms, sero-sorting partners, or choosing less-risky sexual activities). And, because HIV-positive people with durably suppressed or undetectable amounts of HIV in their blood cannot transmit HIV to sexual partners, sexual activity with HIV-positive partners on effective treatment is a form of safe sex (to prevent HIV infection). This fact has given rise to the concept of "U=U" ("Undetectable = Untransmittable").
=== Other forms of safe sex ===
Other methods proven effective at reducing STI risks during sexual activity are:
Immunization against certain sexually-transmitted viruses. The most common vaccines protect against hepatitis B and human papilloma virus (HPV), which can cause cervical cancer, penile cancer, oral cancer, and genital warts. Immunization before initiation of sexual activity increases effectiveness of these vaccines. HPV vaccines are recommended for all teen girls and women as well as teen boys and men through age 26 and 21 respectively.
Limiting numbers of sexual partners, particularly casual sexual partners, or restricting sexual activity to those who know and share their STI status, can also reduce STI risks. Monogamy or polyfidelity, practiced faithfully, is safe (as far as STIs are concerned) when all partners are non-infected. However, a number of monogamous people have been infected with sexually transmitted infections by partners who are sexually unfaithful, have used injection drugs, or were infected by previous sexual partners. The same risks apply to polyfidelitous people, who face higher risks depending on how many people are in the polyfidelitous group.
Communication with sexual partners about sexual history and STI status, preferred safe sex practices, and acceptable risks for partnered sexual activities.
Engaging in less-risky sexual activities. In general, solo sexual activities are less risky than partnered activities. Sexual penetration of orifices (mouth, vagina, anus) and sharing body fluids (such as semen, blood, vaginal fluids, and rectal mucus) between sexual partners carry the most risk for STIs.
Regular STI testing and treatment, especially by those who are sexually active with more than one casual sexual partner. It is possible to attain and show proof of STD-free-verification through online dating apps and websites.
Penile circumcision. Some research suggests that circumcising (removing) the foreskin of the penis can reduce the risk of contracting HIV. Some advocacy groups dispute these findings.
== Ineffective methods ==
Most methods of contraception are not effective at preventing the spread of STIs. This includes birth control pills, vasectomy, tubal ligation, periodic abstinence, IUDs and multiple non-barrier methods of pregnancy prevention. However, condoms, when used correctly, significantly reduces the risks of STI transmission and unwanted pregnancy.
The spermicide nonoxynol-9 has been claimed to reduce the likelihood of STI transmission. However, a technical report from 2001 by the World Health Organization has shown that nonoxynol-9 is an irritant and can produce tiny tears in mucous membranes, which may increase the risk of transmission by offering pathogens more easy points of entry into the system. They reported that nonoxynol-9 lubricant do not have enough spermicide to increase contraceptive effectiveness cautioned they should not be promoted. There is no evidence that spermicidal condoms are better at preventing STD transmission compared to condoms that do not have spermicide. If used properly, spermicidal condoms can prevent pregnancy, but there is still an increased risk that nonoxynyl-9 can irritate the skin, making it more susceptible for infections.
The use of a diaphragm or contraceptive sponge provides some women with better protection against certain sexually transmitted infections, but they are not effective for all STIs.
Hormonal methods of preventing pregnancy (such as oral contraceptives [i.e. 'The pill'], depoprogesterone, hormonal IUDs, the vaginal ring, and the patch) offer no protection against STIs. The copper intrauterine device and the hormonal intrauterine device provide an up to 99% protection against pregnancies but no protection against STIs. Women with copper intrauterine device may be subject to greater risk of infection from bacterial infectious such as gonorrhea or chlamydia, although this is debated.
Coitus interruptus (or "pulling out"), in which the penis is removed from the vagina or mouth before ejaculation, may reduce transmission of STIs but still carries significant risk. This is because pre-ejaculate, a fluid that oozes from the penile urethra before ejaculation, may contain STI pathogens. Additionally, the microbes responsible for some diseases, including genital warts and syphilis, can be transmitted through skin-to-skin or mucous membrane contact.
== Anal sex ==
Unprotected anal penetration is considered a high-risk sexual activity because the thin tissues of the anus and rectum can be easily damaged. Slight injuries can allow the passage of bacteria and viruses, including HIV. This includes penetration of the anus by fingers, hands, or sex toys such as dildos. Also, condoms may be more likely to break during anal sex than during vaginal sex, increasing the risk of STI transmission.
The main risk that individuals are exposed to when performing anal sex is the transmission of HIV. Other possible infections include hepatitis A, B and C; intestinal parasite infections like Giardia; and bacterial infections such as Escherichia coli.
Anal sex should be avoided by couples in which one of the partners has been diagnosed with an STI until the treatment has proven to be effective.
In order to make anal sex safer, the couple must ensure that the anal area is clean and the bowel empty and the partner on whom anal penetration occurs should be able to relax. Regardless of whether anal penetration occurs by using a finger or the penis, the condom is the best barrier method to prevent transmission of STI. Enemas should not be used as they can increase the risk of HIV infection and lymphogranuloma venereum proctitis.
Since the rectum can be easily damaged, the use of lubricants is highly recommended even when penetration occurs by using the finger. Especially for beginners, using a condom on the finger is both a protection measure against STI and a lubricant source. Most condoms are lubricated and they allow less painful and easier penetration. Oil-based lubricants damage latex and should not be used with condoms; water-based and silicone-based lubricants are available instead. Non-latex condoms are available for people who are allergic to latex made out of polyurethane or polyisoprene. Polyurethane condoms can safely be used with oil-based lubricant. The "female condom" may also be used effectively by the anal receiving partner.
Anal stimulation with a sex toy requires similar safety measures to anal penetration with a penis, in this case using a condom on the sex toy in a similar way.
It is important that the man washes and cleans his penis after anal intercourse if he intends to penetrate the vagina. Bacteria from the rectum are easily transferred to the vagina, which may cause vaginal and urinary tract infections.
When anal–oral contact occurs, protection is required since this is a risky sexual behavior in which illnesses such as hepatitis A or STIs can be easily transmitted, as well as enteric infections. The dental dam or plastic wrap are effective protection means whenever anilingus is performed.
== Sex toys ==
Putting a condom on a sex toy provides better sexual hygiene and can help to prevent transmission of infections if the sex toy is shared, provided the condom is replaced when used by a different partner. Some sex toys are made of porous materials, and pores retain viruses and bacteria, which makes it necessary to clean sex toys thoroughly, preferably with use of cleaners specifically for sex toys. Glass is non-porous and medical grade glass sex toys more easily sterilized between uses.
In cases in which one of the partners is treated for an STI, it is recommended that the couple not use sex toys until the treatment has proved to be effective.
All sex toys have to be properly cleaned after use. The way in which a sex toy is cleaned varies on the type of material it is made of. Some sex toys can be boiled or cleaned in a dishwasher. Most of the sex toys come with advice on the best way to clean and store them and these instructions should be carefully followed. A sex toy should be cleaned not only when it is shared with other individuals but also when it is used on different parts of the body (such as mouth, vagina or anus).
Toys should be made of body-safe materials. Only materials that can be safely placed in the mouth or safely placed on the skin are safe to use. A number of soft toys are made of materials that are toxic and impossible to properly clean. Some soft toys are made of medical grade silicone which is properly non-porous and non-reactive with the body. Toys from unreputable sellers may be mis-labeled. Other commonly recognized as safe materials include glass and titanium. If the material it is made of has additives such as pigments, those may also be toxic. The list of safe materials often overlaps with ||Body piercing materials.||
A sex toy should regularly be checked for scratches or breaks that can be breeding ground for bacteria. It is best if the damaged sex toy is replaced by a new undamaged one. Even more hygiene protection should be considered by pregnant women when using sex toys. Sharing any type of sex toy that may draw blood, like whips or needles, is not recommended, and is not safe.
When using sex toys in the anus, sex toys "...can easily get lost" as "rectal muscles contract and can suck an object up and up, potentially obstructing the colon"; to prevent this serious problem, sex toy users are advised to use sex "...toys with a flared base or a string".
== Abstinence ==
Sexual abstinence reduces STIs and pregnancy risks associated with sexual contact, but STIs may also be transmitted through non-sexual means, or by rape. HIV may be transmitted through contaminated needles used in tattooing, body piercing, or injections. Medical or dental procedures using contaminated instruments can also spread HIV, while some health-care workers have acquired HIV through occupational exposure to accidental injuries with needles. Evidence does not support the use of abstinence-only sex education. Abstinence-only sex education programs have been found to be ineffective in decreasing rates of HIV infection in the developed world and unplanned pregnancy. Abstinence-only sex education primarily relies on the consequences of character and morality while health care professionals are concerned about matters regarding health outcomes and behaviors. Though abstinence is the best course to prevent pregnancy and STIs, in reality, it leaves young people without the information and skills they need to avoid unwanted pregnancies and STIs.
== See also ==
Bareback (sex)
Celibacy
Human sexual activity
Masturbation
Misconceptions about HIV/AIDS
Party and play
Post-exposure prophylaxis
Sisters of Perpetual Indulgence
Terrence Higgins Trust
== References ==
== External links ==
"Prevention – Sexually Transmitted Disease, AGUM (Association of Genital Urinary Medicine) Archived 18 February 2020 at the Wayback Machine
"Guidelines", British Association for Sexual health and HIV (BASHH) | Wikipedia/Barrier_methods |
Long-acting reversible contraceptives (LARC) are methods of birth control that provide effective contraception for an extended period without requiring user action. They include hormonal and non-hormonal intrauterine devices (IUDs) and subdermal hormonal contraceptive implants. They are the most effective reversible methods of contraception because their efficacy is not reliant on patient compliance. The failure rates of IUDs and implants is less than 1% per year.
LARCs are often recommended to people seeking convenient and cost effective contraception. In one study, LARC users saved thousands of dollars over a five-year period compared to those who buy condoms and birth control pills. LARCs can generally be safely and effectively used by people of any body weight, adolescents, and people who have not yet had children.
In 2008, the American College of Obstetrics and Gynecologists (ACOG) launched The Long-Acting Reversible Contraception Program with the intention to reduce rates of unintended pregnancy by promoting LARCs, often referred to as a "LARC-first" model. Rates of LARC use in the United States rose steadily in that time frame, from 3.7% in 2007 to 10% in 2019. LARC methods are most popular amongst people in their late teens and early twenties. LARC use varies globally, with different regions reporting different use rates. An estimated 161 million people of reproductive age use an IUD and an additional 25 million use an implant; this is 19.4% of the estimated global population of women of reproductive age.
== Methods ==
LARC methods include IUDs and the subdermal implant.
IUDs, also sometimes referred to as IUS (intrauterine system) or IUC (intrauterine contraception), can come in hormonal or nonhormonal varieties.
Hormonal intrauterine devices are sold under the brand names Mirena, Skyla, Liletta, and others.
Nonhormonal intrauterine device with copper are sold under the brand names copper-T and Paraguard.
Subdermal contraceptive implant are sold under the brand names Nexplanon, Implanon, Norplant, Jadelle, and others.
== Medical use ==
=== Contraception ===
LARCs have higher rates of efficacy than do other forms of contraception. This difference is likely due to the difference between "perfect use" and "typical use". Perfect use indicates complete adherence to medication schedules and guidelines. Typical use describes effectiveness in real-world conditions, where patients may not fully adhere to medication regimens. LARC methods require little to no user action after insertion; therefore, LARC perfect use failure rates are the same as their typical use failure rates. LARC failure rates are comparable to those of sterilization. LARCs and sterilization differ in their reversibility.
The implant has a 0.05% failure rate in the first year of use, the levonorgestrel (hormonal) IUD has a 0.1% failure rate in the first year of use, and the copper IUD has a 0.8% failure rate in first year of use. These rates are comparable to those of permanent sterilization procedures, leading to conclusions that LARCs should be offered as "first-line contraception."
=== Additional Uses ===
LARCs can also be used to treat other conditions, primarily by regulating or stopping the bleeding portion of a user's menstrual cycle. LARCs may be used to treat endometriosis and heavy menstrual bleeding. They can also be useful in treating painful menstruation.
Additionally, a copper IUD can be used as emergency contraception if inserted within five days of unprotected sex. This timeframe may be extended if the date of ovulation is known; the copper IUD must be inserted within 5 days of ovulation.
== Side effects and risks ==
Side effects and risks for LARCs vary by type of LARC, with hormonal IUDs, non-hormonal IUDs, and implants all entailing different side effects and risks.
=== Side effects ===
Hormonal IUDs have similar side effects to other forms of hormonal contraception, such as combined and progesterone only oral contraceptives. Hormonal IUDs most frequently cause irregular menstrual bleeding. Other side effects include acne, breast tenderness, headaches, nausea, and mood changes.
The most common side effects of non-hormonal or copper IUDs are increased pain and heavy bleeding during menstruation, and spotting between menstruation. Impacts on menstruation may decrease over the lifespan of the IUD, but spotting between menstruation may become more frequent over time. For some users, these side effects lead them to discontinue use.
The most common side effect of the contraceptive implant is irregular bleeding, which includes both reduced and increased levels of bleeding. Other side effects include mood changes and mild insulin resistance.
=== Risks ===
IUD use carries some additional risks. Both hormonal and non-hormonal IUDs may lead to developing non-cancerous ovarian cysts. It is also possible that an IUD may be expelled (fall out) from the uterus. The IUD may also perforate (tear) the uterine wall. This is extremely rare and a medical emergency.
== Society and culture ==
=== Cost and benefit ===
All LARCs are designed to last for at least three years, with some options (Paraguard Copper IUD) lasting for at least ten years. Although they have higher up-front costs (out-of-pocket costs can range between $500 and $1300), that cost purchases coverage for longer than other contraceptive methods, which are often purchased on a monthly basis (for hormonal birth control methods like pills, patches, or rings.) When accounting for upfront costs, failure rates, and side effects, researchers estimate that the most cost effective means of contraception are the Copper IUD, vasectomy, and the levonorgestrel IUD (such as a Mirena). One researcher estimates that use of the levonorgestrel IUD can be up to 31% cheaper than using non-LARC methods such as birth control pills, patch, ring, or injectables. Regardless, the initial out of pocket cost is still too high for many patients, and is one of the biggest barriers to LARC use. Studies conducted in California and St. Louis have shown that rates of LARC usage are dramatically higher when the costs of the methods are either covered or removed.
The Colorado Family Planning Initiative (CPFI), a six-year $23 million privately funded program to expand access to LARCs, This program specifically provided no-cost LARCs to low-income women across the state of Colorado, with the intention of preventing unintended pregnancies within specific groups deemed at high-risk of unintended pregnancy. This program decreased unplanned adolescent pregnancies in Colorado by about half. There was a similar decline of unplanned pregnancies in unmarried women under 25 who have not finished high school. Use of LARC methods by children of child-bearing age in the state increased to 20% during the 2009–2014 period. A 2017 study found that CPFI "reduced the teen birth rate in counties with clinics receiving funding by 6.4 percent over five years. These effects were concentrated in the second through fifth years of the program and in counties with relatively high poverty rates."
=== Promotion ===
The United Kingdom Department of Health has actively promoted LARC use since 2008, particularly for young people; following on from the October 2005 National Institute for Health and Clinical Excellence guidelines, which promoted LARC provision in the United Kingdom, accurate and detailed counseling for women about these methods, and training of healthcare professionals to provide these methods. Giving advice on these methods of contraception has been included in the 2009 Quality and Outcomes Framework "good practice" for primary care.
The use of long-acting reversible contraceptives in the United States has increased nearly fivefold from 1.5% in 2002 to 7.2% in 2011–2013. Increasing access to long-acting reversible contraceptives was listed by the Centers for Disease Control and Prevention as one of the top public health priorities for reducing teen pregnancy and unintended pregnancy in the United States. One study of female family planning providers showed that they were significantly more likely to use LARCs than the general population (41.7% compared to 12.0%) suggesting that the general population has less information or access to LARCs.
=== LARC-First models and backlash ===
Guidelines released in 2009 by the American College of Obstetricians and Gynecologists (ACOG) state that LARC methods are considered to be the first-line option for birth control in the United States, and are recommended for the majority of women. According to the CDC Medical Eligibility Criteria for Contraceptive Use, LARC methods are recommended for the majority of women who have had their first menstruation, regardless of whether they have had any pregnancies. The American Academy of Pediatrics (AAP) in a policy statement and technical report published in October 2014 recommended LARC methods for adolescents.
In the years since ACOG made these recommendations, many researchers have evaluated the impact of the LARC-first model. Because it prioritized the importance of effectiveness of method in contraceptive counseling, patient preferences and priorities were not given adequate attention within contraceptive counseling. Researchers have found that patients experience over-enthusiasm about a particular method as coercive. ACOG practitioners have since come forward with an attempt at re-balancing recommendations to center patient needs and desires in contraceptive counseling. The organization has also formally denounced coercive contraceptive practices, including those that incentivize use of contraception, incentivize use of a particular type of contraception, or make it harder to discontinue use of contraception.
== See also ==
Contraceptive vaginal ring
== References ==
== External links ==
UK National Health Service Long-acting Reversible Contraception Guidelines
Long-acting reversible contraception: the effective and appropriate use of long-acting reversible contraception
Increasing Use of Contraceptive Implants and Intrauterine Devices To Reduce Unintended Pregnancy from the American Congress of Obstetricians and Gynecologists | Wikipedia/Long_acting_reversible_birth_control |
Corporate behaviour is the actions of a company or group who are acting as a single body. It defines the company's ethical strategies and describes the image of the company. Studies on corporate behaviour show the link between corporate communication and the formation of its identity.
== Role ==
Not only does corporate behaviour play various roles within different areas of a business, it also enables businesses to overcome any problems they may face. For example, due to an increase in globalisation, language barriers are likely to increase for organisations creating major problems as day-to-day business may be disrupted. Corporate behaviour enables managers to overcome this problem by improving flexibility. Also, many businesses are struggling to remain competitive in terms of quality and productivity due to intense competition within markets. However, corporate behaviour is able to fix this issue by allowing managers to empower their employees as they are the ones who are able to make a change.
Positive corporate behaviour can result in employees feeling happy and content at work providing their best outcome. This is beneficial for management as it could lead to effective teams being created thus resulting in innovative ideas which is beneficial for the business. It also helps to decrease labour turnover enabling the organisation to retain its most valuable employees.
== Importance ==
Corporate behaviour is important in strengthening relationships within organisations between individuals, teams, and in the organisation as a whole. It is important as it reflects the values of the business and the extent to which it is ethical. Corporate behavior refers to the company values that defines it and makes it different and better than other companies. Portraying positive corporate behavior within a company facilitates strong brand image creation; consequently branding then strengthens the importance associated with corporate behavior.
== Influential factors ==
PESTLE factors influence corporate behaviour in many ways. They cause organisations to change the way they operate; however, the size and nature of change is dependent upon which factor is causing the change (political, economic, social, technological, legal, or environmental). External forces are a significant factor of influence over corporate behaviour, hence the term corporate citizenship.
=== Political ===
Political factors such as property rights, the rule of law and the status of governments influence corporate and economic landscapes. Examples of political factors could be changes in government legislation. This could affect an organisation's corporate behaviour as they would have to change the way they operate in order to implement these changes; some employees may not like the new changes made.
=== Economic ===
Recession is an example of an economic factor. If the economy were to be in a recession, businesses may find they have to reduce jobs. This would affect corporate behaviour as business teams would be short of skills and ideas in order to operate effectively. According to the 2013 National Business Ethics Survey of the US workforce, economy and misconduct are not interdependent, which was the traditional view. The report suggested that even though the economy grew in 2011 and 2013, misconduct in businesses was at its lowest. A mixed economy signifies intersections of interests between the private sector of corporations, and the public sector of government.
=== Social ===
Changes in trends and the market is a social factor which affects corporate behaviour. Organisations may have to change their products or services in order to keep up to date with new trends. In order to do this, employees may be required to learn new skills within a short amount of time to make these changes; relationships between employees and management could be at risk due to these changes. Moral imperatives and expectations are also taken into account. Where social issues are shared by many companies across multiple industries, it may often be addressed most effectively through cooperative models and initiatives.
=== Technological ===
Implementing technology within organisations could mean more virtual meetings and fewer face to face meetings. As a result, relationships between management and employees could weaken as a result of less face to face conversations.
=== Legal ===
Legislative rules such as tax may increase which would increase an organisations costs. Changes such as changing the way the organisation operates may have to be made in order to cover these extra costs.
=== Environmental ===
Corporate Environmental Responsibility aims to create goodwill for corporations in various ways, with regards to society. Environmental factors could be any factors which prevent damage to the environment. For example, remote work may be required to reduce the number of employees physically travelling to offices thus reducing greenhouse gas emissions. However, this may lead to isolation as communication is reduced, weakening corporate behaviour within firms.
== Stakeholder influence ==
Businesses have many stakeholders who influence corporate behaviour. However, businesses who adopt the stakeholder theory are likely to appeal more to their stakeholders as they are showing their care and commitment towards them. This helps to strengthen the corporate behaviour within a firm and reduces the need for stakeholders to demand change. With the various factors affecting society and economy in modern times, stakeholders are increasingly showing an interest in Corporate Social Responsibility (CSR). Strategic CSR is also considered a marketing strategy and therefor a potential source of competitive advantage.
== See also ==
Business ethics
Corporate crime
Corporate culture
Corporate governance
Corporate law
Corporation
Normative ethics
PESTLE
Shareholder
Stakeholder concept
== Notes == | Wikipedia/Corporate_behavior |
Globally approximately 45% of those who are married and able to have children use contraception. As of 2007, IUDs were used by about 17% of women of child bearing age in developing countries and 9% in developed countries or more than 180 million women worldwide. Avoiding sex when fertile is used by about 3.6% of women of childbearing age, with usage as high as 20% in areas of South America. As of 2005, 12% of couples are using a male form of contraception (either condoms or a vasectomy) with rates of up to 30% in the developed world.
As of 2012, 57% of women of child bearing age wanted to avoid pregnancy (867 of 1520 million). About 222 million women however were not able to access birth control, 53 million of whom were in sub-Saharan Africa and 97 million of whom were in Asia. Many countries limit access to birth control due to religious and political reasons.
== Africa ==
Contraceptive use among women in Sub-Saharan Africa has risen from about 5% in 1991 to about 30% in 2006. However, due to extreme poverty, lack of access to birth control, and restrictive abortion laws, many women still resort to clandestine abortion providers for unintended pregnancy, resulting in about 3% obtaining unsafe abortions each year. South Africa, Botswana, and Zimbabwe have successful family planning programs, but other central and southern African countries continue to encounter extreme difficulties in achieving higher contraceptive prevalence and lower fertility for a wide variety of compounding reasons.
== China ==
The one-child policy of the People's Republic of China required couples to have no more than one child. Beginning in 1979, the policy was implemented to control rapid population growth. Chinese women receive free contraception and family planning services. Greater than 70% of those of childbearing age use contraception. Since the policy was put into place in 1979, over 400 million births have been prevented. Because of various exemptions, fertility rate is about 1.7 children per woman, down from 5.9 in the 1960s. A strong preference for boys and free access to fetus sex determination and abortion has resulted in an artificially high proportion of males in both rural and urban areas.
Beginning January 1, 2016, China officially abolished the one-child policy. The Chinese government decided to allow families to have a second child to supposedly grow a bigger work force and allow the aging population to relax more. They predict that another economic boom will occur in the near future. The new policy was also seen as a solution to the massive gender disparity, with China's current population leaning heavily toward males. There are no concrete estimates for the new rate of growth of the Chinese population, but there are testimonies from the citizens about their new freedom. Some mothers have said that they are excited at the opportunity of having another child, while others still follow the one child tradition.
== India ==
Awareness of contraception is near-universal among married women in India. However, the vast majority of married Indians (76% in a 2009 study) reported significant problems in accessing a choice of contraceptive methods. In 2009, 48.3% of married women were estimated to use a contraceptive method, i.e. more than half of all married women did not. About three-fourths of these were using female sterilization, which is by far the most prevalent birth-control method in India. Condoms, at a mere 3%, were the next most prevalent method. Meghalaya, Bihar and Uttar Pradesh had the lowest usage of contraception among all Indian states with rates below 30%.
== Pakistan ==
In 2011 just one in five Pakistani women aged 15 to 49 used modern birth control. In 1994, Pakistan pledged that by 2010 it would provide universal access to family planning. but contraception is shunned under traditional social norms. Most women who say they do not want any more children or would like to wait a period of time before their next pregnancy do not have the contraceptive resources available to them in order to do so. In the 1990s, women increasingly reported wanting fewer children, and 24 percent of recent births were reported to be unwanted or mistimed. The rate of unwanted pregnancies is higher for women living in poor or rural environments; with two-thirds of women live in rural areas. While 96 percent of married women were reported to know about at least one method of contraception, only half of them had ever used it. The most commonly reported reasons for married women electing not to use family planning methods include the belief that fertility should be determined by God (28%); opposition to use by the woman, her husband, others or a perceived religious prohibition (23%); infertility (15%); and concerns about health, side effects or the cost of family planning (12%).
== United Kingdom ==
Contraception has been available for free under the National Health Service since 1974, and 74% of reproductive age women use some form of contraception. The levonorgestrel intrauterine system has been massively popular. Sterilization is popular in older age groups, among those 45-49, 29% of men and 21% of women have been sterilized. Female sterilization has been declining since 1996, when the intrauterine system was introduced. Emergency contraception has been available since the 1970s, a product was specifically licensed for emergency contraception in 1984, and emergency contraceptives became available over the counter in 2001. Since becoming available over the counter it has not reduced the use of other forms of contraception, as some predicted it might. In any year only 5% of women of childbearing age use emergency hormonal contraception. Despite widespread availability of contraceptives, almost half of pregnancies were unintended circa 2005. Abortion was legalized in 1967, however still remained illegal in Northern Ireland until 2020.
== United States ==
As of 2008, in the United States, 99% of sexually active women have used birth control at some point in time. In 2015-2017, 64.9% of women aged 15-49 used a form of birth control. The most common forms of birth control were female sterilization (18.6%), oral contraceptive pills (12.6%), long-acting reversible contraceptives (10.3%), and male condoms (8.7%). Despite the availability of highly effective contraceptives, in 2011, 45% of pregnancies were unintended. In 2002, contraceptive use saved about $19 billion in direct medical costs.
== References == | Wikipedia/Prevalence_of_birth_control |
There are many methods of birth control (or contraception) that vary in requirements, side effects, and effectiveness. As the technology, education, and awareness about contraception has evolved, new contraception methods have been theorized and put in application. Although no method of birth control is ideal for every user, some methods remain more effective, affordable or intrusive than others. Outlined here are the different types of barrier methods, hormonal methods, various methods including spermicides, emergency contraceptives, and surgical methods and a comparison between them.
While many methods may prevent conception, only male and female condoms are effective in preventing sexually transmitted infections.
== Methods ==
=== Hormonal methods ===
The IUD (intrauterine device) is a T-shaped device that is inserted into the uterus by a trained medical professional. There are two different types of IUDs: copper or hormonal. The copper IUD (also known as a copper T intrauterine device) is a non-hormonal option of birth control. It is wrapped in copper which creates a toxic environment for sperm and eggs, thus preventing pregnancy. The failure rate of a copper IUD is approximately 0.8% and can prevent pregnancy for up to 10 years. The hormonal IUD (also known as levonorgestrel intrauterine system or LNg IUD) releases a small amount of the hormone called progestin that can prevent pregnancy for 3–8 years with a failure rate of 0.1-0.4%. IUDs can be removed by a trained medical professional at any time before the expiration date to allow for pregnancy.
Oral contraceptives are another option, these are commonly known as 'the pill'. These must be taken at the same time every day in order to be the most effective. There are two different options, there is a combined pill that contains both of the hormones estrogen and progestin, and a progestin-only pill. The failure rate of each of these oral contraceptives is 7%.
Some choose to get an injection or a shot in order to prevent pregnancy. This is an option where a medical professional will inject the hormone progestin into a woman's arm or buttocks every 3 months to prevent pregnancy. The failure rate is 4%.
Women can also get an implant into their upper arm that releases small amounts of hormones to prevent pregnancy. The implant is a thin rod-shaped device that contains the hormone progestin that is inserted into the upper arm and can prevent pregnancy for up to 3 years. The failure rate for this method is 0.1%.
The patch is another simple option, it is a skin patch containing the hormones progestin and estrogen that is absorbed into the blood stream preventing pregnancy. The patch is typically worn on the lower abdomen and replaced once a week. The failure rate for this is 7%.
The hormonal vaginal contraceptive ring is a ring that contains the hormones progestin and estrogen that a woman inserts into the vagina. It is replaced once a month and has a failure rate of 7%.
=== Barrier methods ===
The diaphragm or cervical cap is a small shallow cup-like cap that is inserted into the vagina with spermicide to cover the cervix and block sperm from entering the uterus. It is inserted before sexual intercourse and comes in different sizes. It needs to be fitted by a medical professional. It has a failure rate of 17%.
A contraceptive sponge is another contraceptive method. Like the diaphragm, the contraceptive sponge contains spermicide and is inserted into the vagina and placed over the cervix to prevent sperm from entering the uterus. The sponge must be kept in place 6 hours after sexual intercourse before it can be removed and discarded. The failure rate for women who have had a baby before is 27%; for those who have not had a baby, the failure rate is 14%.
The male condom is typically made of latex (but other materials are available, such as lambskin, if either partner has a latex allergy). The male condom is placed over the male's penis and prevents the sperm from entering the partner's body. It can prevent pregnancy, and STIs such as, but not limited to, HIV if used appropriately. Male condoms can only be used once and are easily accessible at local stores in most countries. The failure rate is 13%.
The female condom is worn by the woman; it is inserted into the vagina and prevents the sperm from entering her body. It can help prevent STIs and can be inserted up to 8 hours before intercourse. The failure rate is 21%.
=== Other methods ===
Spermicides come in various forms such as: gels, foams, creams, film, suppositories, or tablets. The spermicides create an environment in which sperm can no longer live. Though typically used in addition to the male condom, diaphragm, or cervical cap, they can also be used by themselves. They are put into the vagina no more than an hour before intercourse and kept inside the vagina for 6–8 hours after intercourse. The failure rate is 21%.
In the fertility awareness-based method a woman who has a predictable and consistent menstrual cycle tracks the days that she is fertile. The typical woman has approximately 9 fertile days a month and either avoids intercourse on those days or uses an alternative birth control method for that period of time. The failure rate is between 2-23%.
Lactational amenorrhea (LAM) is an option for women who have had a baby within the past 6 months and are breastfeeding. This method is only successful if it has been less than 6 months since the birth of the baby, they must be fully breastfeeding their baby, and not having any periods. The method is almost as effective as an oral contraceptive if the 3 conditions are strictly followed.
The 'pull out method' or coitus interruptus is a method where the male will remove his penis from the vagina before ejaculating; this prevents sperm from reaching the egg and can prevent pregnancy. This method has to be done correctly every time and is best if used in addition to other forms of birth control. It has a failure rate of approximately 22%.
=== Emergency contraceptives ===
A copper IUD can be used as an emergency contraceptive as long as it is inserted within 5 days after intercourse.
There are two different types of emergency contraceptive pills, one contains levonorgestrel and can prevent pregnancy if taken within 3 days of intercourse. The other contains ulipristal acetate and can prevent pregnancy if taken within 5 days of intercourse. This option can be used if other birth control methods fail.
Use of an emergency contraceptive should occur as soon as possible after unprotected sexual intercourse to reduce the chance of pregnancy.
=== Surgical methods ===
Tubal ligation is also known as 'tying tubes'. This is the surgical process where medical professional closes or ties the fallopian tubes in order to prevent sperm from reaching the eggs. This is often done as an outpatient surgical procedure and is effective immediately after it is performed. The failure rate is 0.5%.
A vasectomy is a minor surgical procedure where a doctor will cut the vas deferens and seal the ends to prevent sperm from reaching the penis and ultimately the egg. The method is usually successful after 12 weeks post-procedure or when the sperm count is zero. The failure rate is 0.15%.
== User dependence ==
Different methods require different levels of diligence by users. Methods with little or nothing to do or remember, or that require a clinic visit less than once per year are said to be non-user dependent, forgettable, or top-tier methods. Intrauterine methods, implants, and sterilization fall into this category. For methods that are not user dependent, the actual and perfect-use failure rates are very similar.
Many hormonal methods of birth control, and LAM require a moderate level of thoughtfulness. For many hormonal methods, clinic visits must be made every three months to a year to renew the prescription. The pill must be taken every day, the patch must be reapplied weekly, or the ring must be replaced monthly. Injections are required every 12 weeks. The rules for LAM must be followed every day. Both LAM and hormonal methods provide a reduced level of protection against pregnancy if they are occasionally used incorrectly (rarely going longer than 4–6 hours between breastfeeds, a late pill or injection, or forgetting to replace a patch or ring on time). The actual failure rates for LAM and hormonal methods are somewhat higher than the perfect-use failure rates.
Higher levels of user commitment are required for other methods. Barrier methods, coitus interruptus, and spermicides must be used at every act of intercourse. Fertility awareness-based methods may require daily tracking of the menstrual cycle. The actual failure rates for these methods may be much higher than the perfect-use failure rates.
== Side effects ==
Different forms of birth control have different potential side effects. Not all, or even most, users will experience side effects from a method. The less effective the method, the greater the risk of pregnancy, and the side effects associated with pregnancy.
Minimal or no side effects occur with coitus interruptus, fertility awareness-based, and LAM. Some forms of periodic abstinence encourage examination of the cervix; insertion of the fingers into the vagina to perform this examination may cause changes in the vaginal environment. Following the rules for LAM may delay a woman's first post-partum menstruation beyond what would be expected from different breastfeeding practices.
Barrier methods have a risk of allergic reactions. Users sensitive to latex may use barriers made of less allergenic materials - polyurethane condoms, or silicone diaphragms, for example. Barrier methods are also often combined with spermicides, which have possible side effects of genital irritation, vaginal infection, and urinary tract infection.
Sterilization procedures are generally considered to have a low risk of side effects, though some persons and organizations disagree. Female sterilization is a more significant operation than vasectomy, and has greater risks; in industrialized nations, mortality is 4 per 100,000 tubal ligations, versus 0.1 per 100,000 vasectomies.
After IUD insertion, users may experience irregular periods in the first 3–6 months with Mirena, and sometimes heavier periods and worse menstrual cramps with ParaGard. However, continuation rates are much higher with IUDs compared to non-long-acting methods. A positive characteristic of IUDs is that fertility and the ability to become pregnant returns quickly once the IUD is removed.
Because of their systemic nature, hormonal methods have the largest number of possible side effects. Combined hormonal contraceptives contain estrogen and progestin hormones. They can come in formulations such as pills, vaginal rings, and transdermal patches. Most people who use combined hormonal contraception experience breakthrough bleeding within the first 3 months. Other common side effects include headaches, breast tenderness, and changes in mood. Side effects from hormonal contraceptives typically disappear over time (3-5 months) with consistent use. Less common effects of combined hormonal contraceptives include increasing the risk of deep vein thrombosis to 2-10 per 10,000 women per year and venous thrombotic events (see venous thrombosis) to 7-10 per 10,000 women per year.
Hormonal contraceptives can come in multiple forms including injectables. Depot medroxyprogesterone acetate (DMPA), a progestin-only injectable, has been found to cause amenorrhea (cessation of menstruation); however, the irregular bleeding pattern returns to normal over time. DMPA has also been associated with weight gain. Other side effects more commonly associated with progestin-only products include acne and hirsutism. Compared to combined hormonal contraceptives, progestin-only contraceptives typically produce a more regular bleeding pattern.
=== Sexually transmitted infection prevention ===
Male and female condoms provide significant protection against sexually transmitted infections (STIs) when used consistently and correctly. They also provide some protection against cervical cancer. Condoms are often recommended as an adjunct to more effective birth control methods (such as IUD) in situations where STI protection is also desired.
Other barrier methods, such as diaphragms may provide limited protection against infections in the upper genital tract. Other methods provide little or no protection against sexually transmitted infections.
== Effectiveness ==
=== Cost and cost-effectiveness ===
Family planning is among the most cost-effective of all health interventions. Costs of contraceptives include method costs (including supplies, office visits, training), cost of method failure (ectopic pregnancy, spontaneous abortion, induced abortion, birth, child care expenses) and cost of side effects. Contraception saves money by reducing unintended pregnancies and reducing transmission of sexually transmitted infections. By comparison, in the US, method related costs vary from nothing to about $1,000 for a year or more for reversible contraception.
During the initial five years, vasectomy is comparable in cost to the IUD. Vasectomy is much less expensive and safer than tubal ligation. Since ecological breastfeeding and fertility awareness are behavioral they cost nothing or a small amount upfront for a thermometer or training. Fertility awareness based methods can be used throughout a woman's reproductive lifetime.
Not using contraceptives is the most expensive option. While in that case there are no method related costs, it has the highest failure rate, and thus the highest failure related costs. Even if one only considers medical costs relating to preconception care and birth, any method of contraception saves money compared to using no method.
The most effective and the most cost-effective methods are long-acting methods. Unfortunately these methods often have significant up-front costs, and requiring the user to pay a portion of these costs prevents some from using more effective methods. Contraception saves money for the public health system and insurers.
=== Effectiveness calculation ===
Failure rates may be calculated by either the Pearl Index or a life table method. A "perfect-use" rate is where all rules of the method are rigorously followed, and (if applicable) the method is used for every act of intercourse.
Actual failure rates are higher than perfect-use rates for a variety of reasons:
Mistakes on the part of those providing instructions on how to use the method.
Mistakes on the part of the method's users.
Conscious user non-compliance with the method.
Insurance providers sometimes impede access to medications (e.g. require prescription refills monthly).
For instance, someone using oral forms of hormonal birth control might be given incorrect information by a health care provider as to the frequency of intake, or for some reason does not take the pill one or several days, or not go to the pharmacy on time to renew the prescription, or the pharmacy might be unwilling to provide enough pills to cover an extended absence.
=== Effectiveness comparison ===
The table below color codes the typical use and perfect use failure rates, where the failure rate is measured as the expected number of pregnancies per year per woman using the method:
For example, a failure rate of 20% means that 20 of 100 women become pregnant during the first year of use. Note that the rate may go above 100% if all women, on average, become pregnant within less than a year. In the degenerated case of all women becoming pregnant instantly, the rate would be infinite.
In the user action required column, items that are non-user dependent (require action once per year or less) also have a blue background.
Some methods may be used simultaneously for higher effectiveness rates. For example, using condoms with spermicides the estimated perfect use failure rate would be comparable to the perfect use failure rate of the implant. However, mathematically combining the rates to estimate the effectiveness of combined methods can be inaccurate, as the effectiveness of each method is not necessarily independent.
If a method is known or suspected to have been ineffective, such as a condom breaking, or a method could not be used, as is the case for rape when user action is required for every act of intercourse, emergency contraception (ECP) may be taken 72 to 120 hours after sexual intercourse. Emergency contraception should be taken shortly before or as soon after intercourse as possible, as its efficacy decreases with increasing delay. Although ECP is considered an emergency measure, levonorgestrel ECP taken shortly before sexual intercourse may be used as a primary method for women who have sexual intercourse only a few times a year and want a hormonal method, but do not want to take hormones all the time. The failure rate of repeated or regular use of LNG ECP is similar to the rate for those using a barrier method.
=== Table notes ===
== See also ==
Male contraceptive
== References == | Wikipedia/Comparison_of_birth_control_methods |
Immunocontraception is the use of an animal's immune system to prevent it from fertilizing offspring. Contraceptives of this type are not currently approved for human use.
Typically immunocontraception involves the administration of a vaccine that induces an adaptive immune response which causes an animal to become temporarily infertile. Contraceptive vaccines have been used in numerous settings for the control of wildlife populations. However, experts in the field believe that major innovations are required before immunocontraception can become a practical form of contraception for human beings.
Thus far immunocontraception has focused on mammals exclusively. There are several targets in mammalian sexual reproduction for immune inhibition. They can be organized into three categories.
Gamete production
Organisms that undergo sexual reproduction must first produce gametes, cells which have half the typical number of chromosomes of the species. Often immunity that prevents gamete production also inhibits secondary sexual characteristics and so has effects similar to castration.
Gamete function
After gametes are produced in sexual reproduction, two gametes must combine during fertilization to form a zygote, which again has the full typical number of chromosomes of the species. Methods that target gamete function prevent this fertilization from occurring and are true contraceptives.
Gamete outcome
Shortly after fertilization a zygote develops into a multicellular embryo that in turn develops into a larger organism. In placental mammals this process of gestation occurs inside the reproductive system of the mother of the embryo. Immunity that targets gamete outcome induces abortion of an embryo while it is within its mother's reproductive system.
== Medical use ==
Immunocontraception in not currently available but is under study.
=== Obstacles ===
==== Variability of immunogenicity ====
In order for an immunocontraceptive to be palatable for human use, it would need to meet or exceed the efficacy rates of currently popular forms of contraception. Currently the maximum reduction of fertility due to sperm vaccines in laboratory experiments with mice is ~75%. The lack of efficacy is due to variability of immunogenicity from one animal to another. Even when exposed to the exact same vaccine, some animals will produce abundant antibody titers to the vaccine's antigen, while others produce relatively low antibody titers. In the Eppin trial that attained 100% infertility, a small sample size (only 9 monkeys) was used, and even among this small sample 2 monkeys were dropped from the study because they failed to produce sufficiently high antibody titers.
This trend—high efficacy when antibody titers are above a threshold coupled with variability in how many animals reach such a threshold—is seen throughout immunocontraception and immune-based birth control research. A long-term study of PZP vaccination in deer that spanned 6 years found that infertility was directly related to antibody titers to PZP. The phase II clinical trial of hCG vaccines was quite successful among women who had antibody titers above 50 ng/mL, but quite poor among those with antibody titers below this threshold.
==== Lack of mucosal immunity ====
Mucosal immunity, which includes immune function in the female reproductive tract, is not as well understood as humoral immunity. This may be an issue for certain contraceptive vaccines. For instance, in the second LDH-C4 primate trial that had negative results, all of the immunized macaque monkeys developed high antibody titers against LDH-C4 in serum, but antibodies against LDH-C4 were not found in the monkeys' vaginal fluids. If antibodies against LDH-C4 do indeed inhibit fertilization, then this result highlights how the difference in the functioning of mucosal immunity from humoral immunity may be critical to the efficacy of contraceptive vaccines.
== Adverse effects ==
Whenever an immune response is provoked, there is some risk of autoimmunity. Therefore, immunocontraception trials typically check for signs of autoimmune disease. One concern with zona pellucida vaccination, in particular, is that in certain cases it appears to be correlated with ovarian pathogenesis. However, ovarian disease has not been observed in every trial of zona pellucida vaccination, and when observed, has not always been irreversible.
== Gamete production ==
=== Gonadotropin-releasing hormone ===
The production of gametes is induced in both male and female mammals by the same two hormones: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The production of these in turn is induced by a single releasing hormone, gonadotropin-releasing hormone (GnRH), which has been the focus of most of the research into immunocontraception against gamete production. GnRH is secreted by the hypothalamus in pulses and travels to the anterior pituitary gland through a portal venous system. There it stimulates the production of FSH and LH. FSH and LH travel through the general circulatory system and stimulate the functioning of the gonads, including the production of gametes and the secretion of sex steroid hormones. Immunity against GnRH thus lessens FSH and LH production which in turn attenuates gamete production and secondary sexual characteristics.
While GnRH immunity has been known to have contraceptive effects for some time, only in the 2000s has it been used to develop several commercial vaccines. Equity® Oestrus Control is a GnRH vaccine marketed for use in non-breeding domestic horses. Repro-Bloc is GnRH vaccine marketed for use in domestic animals in general. Improvac® is a GnRH vaccine marketed for use in pigs not as a contraceptive, but as an alternative to physical castration for the control of boar taint. Unlike the other products which are marketed for use in domestic animals, GonaCon™ is a GnRH vaccine being developed as a United States Department of Agriculture initiative for use for control of wildlife, specifically deer. GonaCon has also been used on a trial basis to control kangaroos in Australia.
== Gamete function ==
The form of sexual reproduction practiced by most placental mammals is anisogamous, requiring two kinds of dissimilar gametes, and allogamous, such that each individual only produces one of the two kinds of gametes. The smaller gamete is the sperm cell and is produced by males of the species. The larger gamete is the ovum and is produced by females of the species. Under this scheme, fertilization requires two gametes, one from an individual of each sex, in order to occur. Immunocontraception targeting the female gamete has focused on the zona pellucida. Immunocontraception targeting the male gamete has involved many different antigens associated with sperm function.
=== Zona pellucida ===
The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an ovum. The zona pellucida's main function in reproduction is to bind sperm. Immunity against zonae pellucidae causes an animal to produce antibodies that themselves are bound by a zona pellucida. Thus when a sperm encounters an ovum in an animal immunized against zonae pellucidae, the sperm cannot bind to the ovum because its zona pellucida has already been occupied by antibodies. Therefore, fertilization does not occur.
==== Early research ====
Work begun by researchers at the University of Tennessee in the 1970s into immunity against zonae pellucidae resulted in its identification as a target antigen for immunocontraception. The zona pellucida's suitability is a result of it being necessary for fertilization and containing at least one antigen that is tissue-specific and not species-specific. The tissue-specificity implies that immunity against zonae pellucidae will not also affect other tissues in the immunized animal's body. The lack of species-specificity implies that zonae pellucidae harvested from animals of one species will induce an immune response in those of another, which makes zona pellucida antigens readily available, since zonae pellucidae can be harvested from farm animals.
==== Zonagen ====
In 1987, a pharmaceutical company called Zonagen (later renamed Repros Therapeutics) was started with the goal of developing zona pellucida vaccines as an alternative to the surgical sterilization of companion animals and eventually as a contraceptive for human use. The products would be based on research being done at the Baylor College of Medicine by Bonnie S. Dunbar that was funded by Zonagen. However, the relationship between Zonagen and Bonnie Dunbar ended acrimoniously in 1993. Despite claims later that year that development of a contraceptive vaccine was imminent and an agreement with Schering AG for funding for joint development of a contraceptive vaccine for human use, no vaccine was made commercially available and the agreement with Schering was terminated after primate studies were disappointing. The company would go on to pursue other projects and be renamed.
==== Application to wildlife population control ====
Also in the late 1980s, research began into the use of vaccines based around zonae pellucidae harvested from pigs for the purpose of wildlife control. Such porcine zona pellucida (PZP) vaccines were tested in captive and domestic horses in 1986 with encouraging results. This led to the first successful field trial of contraceptive vaccines with free-ranging wildlife, which examined PZP vaccines used upon wild horses of Assateague Island National Seashore in 1988. The successful results of the field trial were maintained by annual booster inoculations.
Following the success of trials with horses, initial trials using captive animals showed promise for the use of PZP vaccines with white-tailed deer and with African elephants. This led to successful field trials of PZP vaccines in white-tailed deer at the Smithsonian Conservation Biology Institute in Front Royal, VA from September 1992 to September 1994 and in African elephants of Kruger National Park in South Africa in 1996.
As a result of these successes, PZP vaccination has become the most popular form of immunocontraception for wildlife. As of 2011, thousands of animals are treated with PZP vaccination every year, including 6 different species of free-ranging wildlife in 52 different locations and 76 captive exotic species in 67 different zoological gardens.
==== Bio Farma ====
In 2012, researchers from Brawijaya University in conjunction with pharmaceutical company Bio Farma received a grant from the Indonesian government to develop a zona pellucida contraceptive vaccine for human use. Instead of pigs, the zonae pellucidae for the program are harvested from cows. The program hopes to mass-produce a contraceptive vaccine in Indonesia in 2013 at the earliest.
==== Viral and microbial vectors ====
While contraceptive vaccines can be delivered remotely, they still require administration to each individual animal that is to be made infertile. Thus contraceptive vaccines have been used to control only relatively small populations of wildlife. Australia and New Zealand have large populations of European invasive species for which such approach will not scale. Research in these countries has therefore focused on genetically modifying viruses or microorganisms that infect the unwanted invasive species to contain immunocontraceptive antigens.
Such research has included targeting the European rabbit (Oryctolagus cuniculus) in Australia by engineering rabbit zona pellucida glycoproteins into a recombinant myxoma virus. This approach has induced marginal reduction of fertility in laboratory rabbits with some of the glycoproteins. Further improvement of efficacy is necessary before such an approach is ready for field trials. Research has also targeted the house mouse (Mus domesticus) in Australia by engineering murine zona pellucida antigens into a recombinant ectromelia virus and a recombinant cytomegalovirus. The latter approach has induced permanent infertility when injected into laboratory mice. However, there is some attenuation of efficacy when it is actually transmitted virally.
In addition to rabbits and mice, this approach has been explored for other animals. Researchers have attempted to replicate similar results when targeting the red fox (Vulpes vulpes) in Australia using such vectors as Salmonella typhimurium, vaccinia, and canine herpesvirus, but no reduction in fertility has been achieved thus far for a variety of reasons. Initial exploration into the control of the common brushtail possum (Trichosurus vulpecula) in New Zealand using the nematode Parastrongyloides trichosuri has identified it as a possible immunocontraceptive vector.
=== Sperm ===
In placental mammals, fertilization typically occurs inside the female in the oviducts. The oviducts are positioned near the ovaries where ova are produced. An ovum therefore needs only to travel a short distance to the oviducts for fertilization. In contrast sperm cells must be highly motile, since they are deposited into the female reproductive tract during copulation and must travel through the cervix (in some species) as well as the uterus and the oviduct (in all species) to reach an ovum. Sperm cells that are motile are spermatozoa.
Spermatozoa are protected from the male's immune system by the blood-testis barrier. However, spermatozoa are deposited into the female in semen, which is mostly the secretions of the seminal vesicles, prostate gland, and bulbourethral glands. In this way antibodies generated by the male are deposited into the female along with spermatozoa. Because of this and the extensive travel in the female reproductive tract, spermatozoa are susceptible to anti-sperm antibodies generated by the male in addition to waiting anti-sperm antibodies generated by the female.
==== Early research ====
In 1899, the discovery of the existence of antibodies against sperm was made independently both by Serge Metchnikoff of the Pasteur Institute and by Nobel prize laureate Karl Landsteiner.
In 1929, the first recorded attempt at immunocontraception was made by Morris Baskin, clinical director of the Denver Maternal Hygiene Committee. In this trial 20 women who were known to have at least 1 prior pregnancy were injected with their husband's semen, and no conception was recorded in 1 year of observation of these couples. A United States patent (number 2103240) was issued in 1937 for this approach as a contraceptive, but no product for widespread consumption ever came from this approach.
==== Renewed interest ====
Throughout the 1990s, there was a resurgence of research in immunocontraception targeting sperm with the hope of developing a contraceptive vaccine for human use. Unlike earlier research which explored the contraceptive effect of immune responses to whole sperm cells, contemporary research has focused on searching for specific molecular antigens that are involved with sperm function.
Antigens that have been identified as potential targets for immunocontraception include the sperm-specific peptides or proteins ADAM, LDH-C4, sp10, sp56, P10G, fertilization antigen 1 (FA-1), sp17, SOB2, A9D, CD52, YLP12, Eppin, CatSper, Izumo, sperm associated antigen 9 (SPAG9), 80 kilodalton human sperm antigen (80 kDa HSA), and nuclear autoantigenic sperm protein (tNASP).
Early primate trials had mixed results. One study examined the sperm-specific isozyme of human lactate dehydrogenase (LDH-C4) combined with a T-cell epitope to create a synthetic peptide that acted as a more potent chimeric antigen. Vaccination of female baboons with this synthetic peptide resulted in a reduced fertility in the trial. However, a second study that examined vaccination of female macaque monkeys with the same synthetic peptide did not find reduced fertility.
Since then, a study examining vaccination based on an epididymal protease inhibitor (Eppin) in male macaque monkeys demonstrated that vaccination against sperm antigens could be an effective, reversible contraceptive in male primates. While 4 of 6 control monkeys impregnated females during the trial, none of the 7 monkeys included in the trial that were vaccinated against Eppin impregnated females, and 4 of these 7 vaccinated monkeys recovered their fertility within a year and a half of observation after the trial.
This illustrated that not only could sperm immunocontraception be effective, but it could have several advantages over zona pellucida vaccines. For instance, sperm vaccines could be used by males, in addition to females.
Additionally, while there are relatively few glycoproteins in the zona pellucida and thus relatively few target antigens for zona pellucida vaccines, more than a dozen prospective target antigens for the inhibition of sperm function have been identified. This relative abundance of prospective target antigens makes the prospects of a multivalent vaccine better for sperm vaccines. A study which examined the use of one such multivalent vaccine in female macaque monkeys found that the monkeys produced antibodies against all antigens included in the vaccine, suggesting the efficacy of the multivalent approach.
Finally, while there has been autoimmune ovarian pathogenesis found in some trials using zona pellucida vaccines, anti-sperm antibodies are not likely to have adverse health effects, since anti-sperm antibodies are produced by up to 70% of men who have had vasectomies, and there has been much investigation into possible adverse health side-effects of the vasectomy procedure.
==== Passive immunity ====
A vaccine induces active immunity when antigens are injected into an animal that cause it to produce desired antibodies itself. In passive immunity the desired antibody titers are achieved by injecting antibodies directly into an animal. The efficacy of such an approach for immunocontraception was demonstrated as early as the 1970s with antibodies against zonae pellucidae in mice during the investigation of the mechanism by which such antibodies inhibited fertility. Because the variability of individual immune response is an obstacle to bringing contraceptive vaccines to market, there has been research into the approach of contraception through passive immunization as an alternative that would be of less duration, but be closer to market. Research done using phage display technology on lymphocytes from immunoinfertile men led to the isolation, characterization, and synthesis of specific antibodies that inhibit fertility by acting against several of the known sperm antigens. This detailed molecular knowledge of antisperm antibodies may be of use in the development of a passive immunocontraceptive product.
== Gamete outcome ==
=== Human chorionic gonadotropin ===
Most of the research into immunity that inhibits gamete outcome has focused on human chorionic gonadotropin (hCG). hCG is not necessary for fertilization, but is secreted by embryos shortly thereafter. Therefore, immunity against hCG does not prevent fertilization. However, it was found that anti-hCG antibodies prevent marmoset embryos from implanting in the endometrium of their mother's uterus.
The main function of hCG is to sustain the ovarian corpus luteum during pregnancy past the time it would normally decay as part of the regular menstrual cycle. For the first 7–9 weeks in humans, the corpus luteum secretes the progesterone necessary to maintain the viability of the endometrium for pregnancy. Therefore, immunity against hCG during this time frame would function as an abortifacient, as confirmed by experiments in baboons. In the scientific literature the more inclusive term "birth control vaccine" rather than "contraceptive vaccine" is used to refer to hCG vaccines.
==== Clinical trials ====
Research begun in the 1970s led to clinical trials in humans of a hCG birth control vaccine. A phase I (safety) clinical trial examined 15 women from clinics in Helsinki, Finland, Uppsala, Sweden, Bahia, Brazil, and Santiago, Chile with a vaccine formed by conjugating the beta subunit of hCG with a tetanus toxoid. The women had previously had tubal ligations. In the trial the immune response was reversible and no significant health issues were found.
This was followed by another phase I trial in 1977-1978 examining previously sterilized women at 5 institutions in India with a more potent vaccine that combined the beta subunit of hCG with the alpha subunit of ovine luteinizing hormone to form a heterospecies dimer conjugated with both tetanus toxoid and diphtheria toxoid. The multiple carriers were used because it was found that a small percentage of women acquired carrier-specific immunosuppression due to repeated injection of conjugates with the same carrier.
This more potent version of the vaccine was used in a phase II (efficacy) trial during 1991-1993 conducted at 3 locations: the All India Institute of Medical Sciences, Safdarjung Hospital in New Delhi, and the Post Graduate Institute of Medical Education and Research in Chandigarh. Primary immunization consisted of 3 injections at 6 week intervals, and 148 women known to be previously fertile completed primary immunization. All women generated antibodies against hCG, but only 119 (80%) generated antibody titers clearly above 50 ng/mL, which was the estimated level for efficacy. Blood samples were taken twice a month, and booster injections were given when antibody titers declined below 50 ng/mL in women who wished to continue using the vaccine. At the completion of the study after 1224 menstrual cycles observed, only 1 pregnancy occurred in a woman having an antibody titer level above 50 ng/mL, and 26 pregnancies occurred among women who had titers below 50 ng/mL.
==== Application to cancer therapy ====
Following these clinical trails of hCG vaccination as a birth control method, hCG was discovered to be expressed in certain kinds of malignant neoplasms, including breast cancer, adenocarcinoma of the prostate, progressive vulvar carcinoma, carcinoma of the bladder, pancreatic adenocarcinoma, cervical carcinoma, gastric carcinoma, squamous-cell carcinoma of the oral cavity and oropharynx, lung carcinoma, and colorectal cancer. Therefore, immunity against hCG has applications such as imaging of cancer cells, selective delivery of cytotoxic compounds to tumor cells, and in at least one case, direct therapeutic effect by preventing establishment, inhibiting the growth, and causing the necrosis of tumors. This has led to interest in developing hCG vaccines specifically for cancer treatment.
==== Ongoing research ====
The vaccine tested in the phase II clinical trial in India did not proceed further because it produced antibody titers of 50 ng/mL for at least 3 months duration in only 60% of women in the trial. Ongoing research in hCG birth control vaccines has focused on improving immunogenicity. A vaccine in which the beta subunit of hCG is fused to the B subunit of Escherichia coli heat-labile enterotoxin has been effective in laboratory mice. It has been approved by the Indian National Review Committee on Genetic Manipulation and is being produced for pre-clinical toxicology testing. If it is determined to be safe, it is planned for clinical trials.
== Wildlife control ==
Immunocontraception is one of the few alternatives to lethal methods for the direct control of wildlife populations. While there was research into the use of hormonal contraception for wildlife control as early as the 1950s that produced pharmacologically effective products, they all proved to be ineffective for wildlife control for a variety of practical reasons. Field trials of immunocontraception in wildlife, on the other hand, established that contraceptive vaccines could be delivered remotely by capture gun, were safe to use in pregnant animals, were reversible, and induced long-lasting infertility, overcoming these practical limitations.
One concern about the use of hormonal contraceptives in general, but especially in wildlife, is that the sex steroid hormones that are used are easily passed, often via the food chain, from animal to animal. This can lead to unintended ecological consequences. For instance, fish exposed to treated human sewage effluents were found to have concentrations of the synthetic hormone levonorgestrel in blood plasma higher than those found in humans taking hormonal contraceptives. Because the antigens used in contraceptive vaccines are protein, not steroids, they are not easily passed from animal to animal without loss of function.
== References == | Wikipedia/Contraceptive_vaccine |
A forced orgasm is consensual BDSM or kinky sexual play whereby a person consents to be forced to orgasm in a way that is beyond their control.
== Purpose ==
The person being brought to involuntary orgasm would typically be put in physical restraints to deprive them of the ability to control the onset and intensity of orgasm, and to increase the feeling of helplessness, a situation which some people find sexually arousing.
== Practice ==
The practice of forced orgasm may also be combined with other orgasm control plays, such as orgasm denial, edging, or ruined orgasms.
With the consenting partner restrained and unable to prevent themselves from being sexually stimulated, the active partner stimulates their genitals and other erogenous zones until the bound partner is brought to orgasm. A range of sexual stimulation can be used, including vaginal sex, oral sex or anal sex. Forced orgasms may also be induced with manual stimulation of the genitals, in the form of a handjob or fingering a vulva/vagina. Alternatively the stimulation may involve the use of vibrating sex toys, such as a vibrator, typically a wand vibrator.
== Stimulation ==
The most common way of achieving orgasm in men is by physical sexual stimulation of the penis. For women, the most common way to achieve orgasm is by direct sexual stimulation of the clitoris (meaning consistent digital, oral or other concentrated friction against the external parts of the clitoris).
== See also ==
Cock and ball torture
Dominatrix
Erotic sexual denial
Maledom
Sensual play
== References == | Wikipedia/Forced_orgasm |
The environmental impact of the energy industry is significant, as energy and natural resource consumption are closely related. Producing, transporting, or consuming energy all have an environmental impact. Energy has been harnessed by human beings for millennia. Initially it was with the use of fire for light, heat, cooking and for safety, and its use can be traced back at least 1.9 million years.
In recent years there has been a trend towards the increased commercialization of various renewable energy sources. Scientific consensus on some of the main human activities that contribute to global warming are considered to be increasing concentrations of greenhouse gases, causing a warming effect, global changes to land surface, such as deforestation, for a warming effect, increasing concentrations of aerosols, mainly for a cooling effect.
Rapidly advancing technologies can potentially achieve a transition of energy generation, water and waste management, and food production towards better environmental and energy usage practices using methods of systems ecology and industrial ecology.
== Issues ==
=== Climate change ===
The scientific consensus on global warming and climate change is that it is caused by anthropogenic greenhouse gas emissions, the majority of which comes from burning fossil fuels with deforestation and some agricultural practices being also major contributors. A 2013 study showed that two thirds of the industrial greenhouse gas emissions are due to the fossil-fuel (and cement) production of just ninety companies around the world (between 1751 and 2010, with half emitted since 1986).
Although there is a highly publicized denial of climate change, the vast majority of scientists working in climatology accept that it is due to human activity. The IPCC report Climate Change 2007: Climate Change Impacts, Adaptation and Vulnerability predicts that climate change will cause shortages of food and water and increased risk of flooding that will affect billions of people, particularly those living in poverty.
One measurement of greenhouse gas related and other Externality comparisons between energy sources can be found in the ExternE project by the Paul Scherrer Institut and the University of Stuttgart which was funded by the European Commission. According to that study, hydroelectric electricity produces the lowest CO2 emissions, wind produces the second-lowest, nuclear energy produces the third-lowest and solar photovoltaic produces the fourth-lowest.
Similarly, the same research study (ExternE, Externalities of Energy), undertaken from 1995 to 2005 found that the cost of producing electricity from coal or oil would double over its present value, and the cost of electricity production from gas would increase by 30% if external costs such as damage to the environment and to human health, from the airborne particulate matter, nitrogen oxides, chromium VI and arsenic emissions produced by these sources, were taken into account. It was estimated in the study that these external, downstream, fossil fuel costs amount up to 1–2% of the EU's entire Gross Domestic Product (GDP), and this was before the external cost of global warming from these sources was even included. The study also found that the environmental and health costs of nuclear power, per unit of energy delivered, was €0.0019/kWh, which was found to be lower than that of many renewable sources including that caused by biomass and photovoltaic solar panels, and was thirty times lower than coal at €0.06/kWh, or 6 cents/kWh, with the energy sources of the lowest external environmental and health costs associated with it being wind power at €0.0009/kWh.
=== Biofuel use ===
Biofuel is defined as solid, liquid or gaseous fuel obtained from relatively recently lifeless or living biological material and is different from fossil fuels, which are derived from long-dead biological material. Various plants and plant-derived materials are used for biofuel manufacturing.
==== Bio-diesel ====
High use of bio-diesel leads to land use changes including deforestation.
==== Firewood ====
Unsustainable firewood harvesting can lead to loss of biodiversity and erosion due to loss of forest cover. An example of this is a 40-year study done by the University of Leeds of African forests, which account for a third of the world's total tropical forest which demonstrates that Africa is a significant carbon sink. A climate change expert, Lee White states that "To get an idea of the value of the sink, the removal of nearly 5 billion tonnes of carbon dioxide from the atmosphere by intact tropical forests is at issue.
According to the U.N. the African continent is losing forest twice as fast as the rest of the world. "Once upon a time, Africa boasted seven million square kilometers of forest but a third of that has been lost, most of it to charcoal."
=== Fossil fuel use ===
The three fossil fuel types are coal, petroleum and natural gas. It was estimated by the Energy Information Administration that in 2006 primary sources of energy consisted of petroleum 36.8%, coal 26.6%, natural gas 22.9%, amounting to an 86% share for fossil fuels in primary energy production in the world.
In 2013 the burning of fossil fuels produced around 32 billion tonnes (32 gigatonnes) of carbon dioxide and additional air pollution. This caused negative externalities of $4.9 trillion due to global warming and health problems (> 150 $/ton carbon dioxide). Carbon dioxide is one of the greenhouse gases that enhances radiative forcing and contributes to global warming, causing the average surface temperature of the Earth to rise in response, which climate scientists agree will cause major adverse effects.
==== Coal ====
==== Petroleum ====
==== Gas ====
Natural gas is often described as the cleanest fossil fuel, producing less carbon dioxide per joule delivered than either coal or oil, and far fewer pollutants than other fossil fuels. However, in absolute terms, it does contribute substantially to global carbon emissions, and this contribution is projected to grow. According to the IPCC Fourth Assessment Report, in 2004 natural gas produced about 5,300 Mt/yr of CO2 emissions, while coal and oil produced 10,600 and 10,200 respectively (Figure 4.4); but by 2030, according to an updated version of the SRES B2 emissions scenario, natural gas would be the source of 11,000 Mt/yr, with coal and oil now 8,400 and 17,200 respectively. (Total global emissions for 2004 were estimated at over 27,200 Mt.)
In addition, natural gas itself is a greenhouse gas far more potent than carbon dioxide when released into the atmosphere but is released in smaller amounts. The environmental impacts of Natural gas also vary substantially on their extraction processes, much natural gas is a byproduct of heavily polluting petroleum extraction and newer techniques for hydraulic fracturing have made natural gas reserves that were previously unaccusable available, but with many more negative environmental and health impacts that traditional natural gas extraction.
=== Electricity generation ===
The environmental impact of electricity generation is significant because modern society uses large amounts of electrical power. This power is normally generated at power plants that convert some other kind of energy into electrical power. Each such system has advantages and disadvantages, but many of them pose environmental concerns.
==== Reservoirs ====
==== Nuclear power ====
The environmental impact of nuclear power results from the nuclear fuel cycle, operation, and the effects of nuclear accidents.
The routine health risks and greenhouse gas emissions from nuclear fission power are significantly smaller than those associated with coal, oil and gas. However, there is a "catastrophic risk" potential if containment fails, which in nuclear reactors can be brought about by over-heated fuels melting and releasing large quantities of fission products into the environment. The most long-lived radioactive wastes, including spent nuclear fuel, must be contained and isolated from humans and the environment for hundreds of thousands of years. The public is sensitive to these risks and there has been considerable public opposition to nuclear power. Despite this potential for disaster, normal fossil fuel related pollution is still considerably more harmful than any previous nuclear disaster.
The 1979 Three Mile Island accident and 1986 Chernobyl disaster, along with high construction costs, ended the rapid growth of global nuclear power capacity. A further disastrous release of radioactive materials followed the 2011 Japanese tsunami which damaged the Fukushima I Nuclear Power Plant, resulting in hydrogen gas explosions and partial meltdowns classified as a Level 7 event. The large-scale release of radioactivity resulted in people being evacuated from a 20 km exclusion zone set up around the power plant, similar to the 30 km radius Chernobyl Exclusion Zone still in effect.
== Mitigation ==
=== Energy conservation ===
Energy conservation refers to efforts made to reduce energy consumption. Energy conservation can be achieved through increased efficient energy use, in conjunction with decreased energy consumption and/or reduced consumption from conventional energy sources.
Energy conservation can result in increased financial capital, environmental quality, national security, personal security, and human comfort. Individuals and organizations that are direct consumers of energy choose to conserve energy to reduce energy costs and promote economic security. Industrial and commercial users can increase energy use efficiency to maximize profit.
The increase of global energy use can also be slowed by tackling human population growth, by using non-coercive measures such as better provision of family planning services and by empowering (educating) women in developing countries.
An EU survey conducted on climate and energy consumption in 2022 found that 63% of people in the European Union want energy costs to be dependent on use, with the greatest consumers paying more. This is compared to 83% in China, 63% in the UK and 57% in the US.
=== Energy policy ===
Energy policy is the manner in which a given entity (often governmental) has decided to address issues of energy development including energy production, distribution and consumption. The attributes of energy policy may include legislation, international treaties, incentives to investment, guidelines for energy conservation, taxation and other public policy techniques.
== See also ==
== References ==
== External links ==
United Nations Development Programme – Environment and Energy for Sustainable Development
Discussion of environmental cost of providing renewable energy – Environment impact of renewable energy technologies | Wikipedia/Environmental_impact_of_the_energy_industry |
Anticonvulsants (also known as antiepileptic drugs, antiseizure drugs, or anti-seizure medications (ASM)) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also used in the treatment of bipolar disorder and borderline personality disorder, since many seem to act as mood stabilizers, and for the treatment of neuropathic pain. Anticonvulsants suppress the uncontrolled and excessive firing of neurons during seizures and in doing so can also prevent the spread of the seizure within the brain.
Conventional antiepileptic drugs have diverse mechanisms of action but many block sodium channels or enhance γ-aminobutyric acid (GABA) function. Several antiepileptic drugs have multiple or uncertain mechanisms of action. Next to voltage-gated sodium channels and components of the GABA system, their targets include GABAA receptors, the GABA transporter type 1, and GABA transaminase. Additional targets include voltage-gated calcium channels, SV2A, and α2δ. By blocking sodium or calcium channels, antiepileptic drugs reduce the release of the excitatory neurotransimtter glutamate, whose release is considered to be elevated in epilepsy, but also that of GABA. This is probably a side effect or even the actual mechanism of action for some antiepileptic drugs, since GABA can itself, directly or indirectly, act pro-convulsively. Another potential target of antiepileptic drugs is the peroxisome proliferator-activated receptor alpha.
Some anticonvulsants have shown antiepileptogenic effects in animal models of epilepsy. That is, they either prevent the development of epilepsy or can halt or reverse the progression of epilepsy. However, no drug has been shown in human trials to prevent epileptogenesis (the development of epilepsy in an individual at risk, such as after a head injury).
Many anticonvulsants are known teratogens and increase the risk of birth defects in the unborn child if taken while pregnant.
== Terminology ==
Anticonvulsants are more accurately called antiepileptic drugs (AEDs) because not every epileptic seizure involves convulsion, and vice versa, not every convulsion is caused by an epileptic seizure. They are also often referred to as antiseizure drugs because they provide symptomatic treatment only and have not been demonstrated to alter the course of epilepsy.
== Approval ==
The usual method of achieving approval for a drug is to show it is effective when compared against placebo, or that it is more effective than an existing drug. In monotherapy (where only one drug is taken) it is considered unethical by most to conduct a trial with placebo on a new drug of uncertain efficacy. This is because untreated epilepsy leaves the patient at significant risk of death. Therefore, almost all new epilepsy drugs are initially approved only as adjunctive (add-on) therapies. Patients whose epilepsy is uncontrolled by their medication (i.e., it is refractory to treatment) are selected to see if supplementing the medication with the new drug leads to an improvement in seizure control. Any reduction in the frequency of seizures is compared against a placebo. The lack of superiority over existing treatment, combined with lacking placebo-controlled trials, means that few modern drugs have earned FDA approval as initial monotherapy. In contrast, Europe only requires equivalence to existing treatments and has approved many more. Despite their lack of FDA approval, the American Academy of Neurology and the American Epilepsy Society still recommend a number of these new drugs as initial monotherapy.
== Drugs ==
In the following list, the dates in parentheses are the earliest approved use of the drug.
=== Aldehydes ===
Paraldehyde (1882). One of the earliest anticonvulsants. It is still used to treat status epilepticus, particularly where there are no resuscitation facilities.
=== Aromatic allylic alcohols ===
Stiripentol (2007). Indicated for the treatment of Dravet syndrome.
=== Barbiturates ===
Barbiturates are drugs that act as central nervous system (CNS) depressants, and by virtue of this they produce a wide spectrum of effects, from mild sedation to anesthesia. The following are classified as anticonvulsants:
Phenobarbital (1912). See also the related drug primidone.
Methylphenobarbital (1935). Known as mephobarbital in the US. No longer marketed in the UK.
Barbexaclone (1982). Only available in some European countries.
=== Benzodiazepines ===
The benzodiazepines are a class of drugs with hypnotic, anxiolytic, anticonvulsive, amnestic and muscle relaxant properties. Benzodiazepines act as a central nervous system depressant. The relative strength of each of these properties in any given benzodiazepine varies greatly and influences the indications for which it is prescribed. Long-term use can be problematic due to the development of tolerance to the anticonvulsant effects and dependency. Of many drugs in this class, only a few are used to treat epilepsy:
Clobazam (1979). Notably, used on a short-term basis around menstruation in women with catamenial epilepsy.
Clonazepam (1974).
Clorazepate (1972).
The following benzodiazepines are used to treat status epilepticus:
Diazepam (1963). Can be given rectally by trained care-givers.
Midazolam (N/A). Increasingly being used as an alternative to diazepam. This water-soluble drug is squirted into the side of the mouth but not swallowed. It is rapidly absorbed by the buccal mucosa.
Lorazepam (1972). Given by injection in hospital.
Nitrazepam, temazepam, and especially nimetazepam are powerful anticonvulsant agents, however their use is rare due to an increased incidence of side effects and strong sedative and motor-impairing properties.
=== Bromides ===
Potassium bromide (1857). The earliest effective treatment for epilepsy. There would not be a better drug until phenobarbital in 1912. It is still used as an anticonvulsant for dogs and cats but is no longer used in humans.
=== Carbamates ===
Felbamate (1993). This effective anticonvulsant has had its usage severely restricted due to rare but life-threatening side effects.
Cenobamate (2019).
=== Carboxamides ===
The following are carboxamides:
Carbamazepine (1963). A popular anticonvulsant that is available in generic formulations.
Oxcarbazepine (1990). A derivative of carbamazepine that has similar efficacy and is better tolerated and is also available generically.
Eslicarbazepine acetate (2009).
Photoswitchable analogues of carbamazepine (2024) are research compounds developed to control its pharmacological activity locally and on demand using light, with the purpose to reduce adverse systemic effects. One of these compounds (carbadiazocine, based on a bridged azobenzene) has been shown to produce analgesia with noninvasive illumination in a rat model of neuropathic pain.
=== Fatty acids ===
The following are fatty-acids:
The valproates — valproic acid, sodium valproate, and divalproex sodium (1967).
Vigabatrin (1989).
Progabide (1987).
Tiagabine (1996).
Vigabatrin and progabide are also analogs of GABA.
=== Fructose derivatives ===
Topiramate (1995).
=== Gabapentinoids ===
Gabapentinoids are used in epilepsy, neuropathic pain, fibromyalgia, restless leg syndrome, opioid withdrawal and generalized anxiety disorder (GAD). Gabapentinoids block voltage-gated calcium channels, mainly the N-Type, and P/Q-type calcium channels. The following are gabapentinoids:
Pregabalin (2004)
Mirogabalin (2019) (Japan only)
Gabapentin (1993)
Gabapentin enacarbil (Horizant) (2011)
Gabapentin extended release (Gralise) (1996)
Gabapentinoids are analogs of GABA, but they do not act on GABA receptors. They have analgesic, anticonvulsant, and anxiolytic effects.
=== Hydantoins ===
The following are hydantoins:
Ethotoin (1957).
Phenytoin (1938).
Mephenytoin.
Fosphenytoin (1996).
=== Oxazolidinediones ===
The following are oxazolidinediones:
Paramethadione.
Trimethadione (1946).
Ethadione.
=== Propionates ===
Beclamide.
=== Pyrimidinediones ===
Primidone (1952).
=== Pyrrolidines ===
Brivaracetam (2016).
Etiracetam.
Levetiracetam (1999).
Seletracetam.
=== Succinimides ===
The following are succinimides:
Ethosuximide (1955).
Phensuximide.
Mesuximide.
=== Sulfonamides ===
Acetazolamide (1953).
Sultiame.
Methazolamide.
Zonisamide (2000).
=== Triazines ===
Lamotrigine (1990).
=== Ureas ===
Pheneturide.
Phenacemide.
=== Valproylamides ===
Valpromide.
Valnoctamide.
=== Other ===
Perampanel.
Stiripentol.
Pyridoxine (1939).
== Non-pharmaceutical anticonvulsants ==
The ketogenic diet and vagus nerve stimulation are alternative treatments for epilepsy without the involvement of pharmaceuticals. The ketogenic diet consists of a high-fat, low-carbohydrate diet, and has shown good results in patients whose epilepsy has not responded to medications and who cannot receive surgery. The vagus nerve stimulator is a device that can be implanted into patients with epilepsy, especially that which originates from a specific part of the brain. However, both of these treatment options can cause severe adverse effects. Additionally, while seizure frequency typically decreases, they often do not stop entirely.
== Treatment guidelines ==
According to guidelines by the American Academy of Neurology and American Epilepsy Society, mainly based on a major article review in 2004, patients with newly diagnosed epilepsy who require treatment can be initiated on standard anticonvulsants such as carbamazepine, phenytoin, valproic acid/valproate semisodium, phenobarbital, or on the newer anticonvulsants gabapentin, lamotrigine, oxcarbazepine or topiramate. The choice of anticonvulsants depends on individual patient characteristics. Both newer and older drugs are generally equally effective in new onset epilepsy. The newer drugs tend to have fewer side effects. For newly diagnosed partial or mixed seizures, there is evidence for using gabapentin, lamotrigine, oxcarbazepine or topiramate as monotherapy. Lamotrigine can be included in the options for children with newly diagnosed absence seizures.
== History ==
The first anticonvulsant was bromide, suggested in 1857 by the British gynecologist Charles Locock who used it to treat women with "hysterical epilepsy" (probably catamenial epilepsy). Bromides are effective against epilepsy, and also cause impotence, which is not related to its anti-epileptic effects. Bromide also suffered from the way it affected behaviour, introducing the idea of the "epileptic personality" which was actually a result of medication. Phenobarbital was first used in 1912 for both its sedative and antiepileptic properties. By the 1930s, the development of animal models in epilepsy research led to the development of phenytoin by Tracy Putnam and H. Houston Merritt, which had the distinct advantage of treating epileptic seizures with less sedation. By the 1970s, a National Institutes of Health initiative, the Anticonvulsant Screening Program, headed by J. Kiffin Penry, served as a mechanism for drawing the interest and abilities of pharmaceutical companies in the development of new anticonvulsant medications.
=== Marketing approval history ===
The following table lists anticonvulsant drugs together with the date their marketing was approved in the US, UK and France. Data for the UK and France are incomplete. The European Medicines Agency approves drugs throughout the European Union. Some of the drugs are no longer marketed.
== Pregnancy ==
Many of the commonly used anticonvulsant/anti-seizure medications (ASMs), such as valproate, phenytoin, carbamazepine, phenobarbital, gabapentin have been reported to cause an increased risk of birth defects including major congenital malformations such as neural tube defects. The risk of birth defects associated with taking these medications while pregnant may be dependent on the dose of the drug and on the timing of gestation (how well developed the baby is). While trying to conceive a child and during pregnancy, medical advice should be followed to optimize the management of the person's epilepsy in order to keep the person and the unborn baby safe from epileptic seizures and also ensure that the risk of birth defects due to in utero exposure of anticonvulsants is as low as possible. Anticonvulsant medications should be carefully monitored during use in pregnancy. For example, since the first trimester is the most susceptible period for fetal development, planning a routine antiepileptic drug dose that is safer for the first trimester could be beneficial to prevent pregnancy complications.
Valproic acid, and its derivatives such as sodium valproate and divalproex sodium, causes cognitive deficit in the child, with an increased dose causing decreased intelligence quotient and use is associated with adverse neurodevelopmental outcomes (cognitive and behavioral) in children. On the other hand, evidence is conflicting for carbamazepine regarding any increased risk of congenital physical anomalies or neurodevelopmental disorders by intrauterine exposure. Similarly, children exposed lamotrigine or phenytoin in the womb do not seem to differ in their skills compared to those who were exposed to carbamazepine.
There is inadequate evidence to determine if newborns of women with epilepsy taking anticonvulsants have a substantially increased risk of hemorrhagic disease of the newborn.
There is little evidence to suggest that anticonvulsant/ASM exposure through breastmilk has clinical effects on newborns. The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study showed that most blood concentrations in breastfed infants of mothers taking carbamazepine, oxcarbazepine, valproate, levetiracetam, and topiramate were quite low, especially in relationship to the mother's level and what the fetal level would have been during pregnancy. (Note: valproic acid is NOT a recommended ASM for people with epilepsy who are considering having children.)
Infant exposure to newer ASMs (cenobamate, perampanel, brivaracetam, eslicarbazepine, rufinamide, levetiracetam, topiramate, gabapentin, oxcarbazepine, lamotrigine, and vigabatrin) via breastmilk was not associated with negative neurodevelopment (such as lower IQ and autism spectrum disorder) at 36 months.
Several studies that followed children exposed to ASMs during pregnancy showed that a number of widely used ones (including lamotrigine and levetiracetam) carried a low risk of adverse neurodevelopmental outcomes (cognitive and behavioral) in children when compared to children born to mothers without epilepsy and children born to mothers taking other anti-seizure medications. Data from several pregnancy registries showed that children exposed to levetiracetam or lamotrigine during pregnancy had the lowest risk of developing major congenital malformations compared to those exposed to other ASMs. The risk of major congenital malformations for children exposed to these ASMs were within the range for children who were not exposed to any ASMs during pregnancy.
People with epilepsy can have healthy pregnancies and healthy babies. However, proper planning and care is essential to minimize the risk of congenital malformations or adverse neurocognitive outcomes for the fetus while maintaining seizure control for the pregnant person with epilepsy. If possible, when planning pregnancy, people with epilepsy should switch to ASMs with the lowest teratogenic risk for major congenital malformations as well as the least risk of adverse neurodevelopmental outcomes (e.g., lower IQ or autism spectrum disorder). They should also work with their healthcare providers to identify the lowest effective ASM dosage that will maintain their seizure control while regularly checking medication levels throughout pregnancy.
Data from studies conducted on women taking antiepileptic drugs for non-epileptic reasons, including depression and bipolar disorder, show that if high doses of the drugs are taken during the first trimester of pregnancy then there is the potential of an increased risk of congenital malformations.
== Research ==
The mechanism of how anticonvulsants cause birth defects is not entirely clear. During pregnancy, the metabolism of many anticonvulsants is affected. There may be an increase in the clearance and resultant decrease in the blood concentration of lamotrigine, phenytoin, and to a lesser extent carbamazepine, and possibly decreases the level of levetiracetam and the active oxcarbazepine metabolite, the monohydroxy derivative. In animal models, several anticonvulsant drugs have been demonstrated to induce neuronal apoptosis in the developing brain.
== References ==
== Further reading ==
Anti epileptic activity of novel substituted fluorothiazole derivatives by Devid Chutia, RGUHS
== External links ==
Drug Reference for FDA Approved Epilepsy Drugs | Wikipedia/Anti-epileptic_drugs |
A webcam model (colloquially, camgirl, camboy, or cammodel) is a video performer who streams on the Internet with a live webcam broadcast. A webcam model often performs erotic acts online, such as stripping, masturbation, or sex acts in exchange for money, goods, or attention. They may also sell videos of their performances. Once viewed as a small niche in the world of adult entertainment, camming became "the engine of the porn industry," according to Alec Helmy, the publisher of XBIZ, a sex-trade industry journal.
As many webcam models operate in the comfort of their own homes, they are free to choose the amount of sexual content for their broadcasts. While most display nudity and sexually provocative behavior, some choose to remain mostly clothed and merely talk about various topics, while still soliciting payment as tips from their fans. Webcam models are predominantly women, and also include noted performers of all genders and sexualities.
== Background ==
The conceptual artist Jenny Ringley is considered the first camgirl. In 1996, as a student at Dickinson College, Ringley created a website called "JenniCam". Her webcam was located in her dorm room and automatically photographed her every few minutes. Ringley viewed her site as a straightforward document of her life. She did not wish to filter the events that were shown on her camera, so sometimes she was shown nude or engaging in sexual behavior, including sexual intercourse and masturbation. These images were then broadcast live over the Internet. Two years later, in 1998, she divided her website's access between free and paying.
Also in 1998, a commercial site called AmandaCam was launched. Amanda's site, like Ringley's, had multiple cameras around her house, which allowed people to look in on her. However, Amanda made an important early discovery that would influence the camming industry for decades to come – that a website's popularity could be greatly increased by enabling viewers to chat with a performer while online. Within her members section, Amanda made it a point to chat with her viewers for over three hours a day. Since the early days of live webcasts by Ringley and Amanda, the phenomenon of camming has grown to become a multibillion-dollar industry, which has an average of at least 12,500 cam models online at any given time, and more than 240,000 viewers at any given time.
=== Payment systems and earnings ===
A camming website acts as an intermediary and aggregator by hosting independent models, and verifies that all are at least 18 years old. Camming websites typically fall into two main categories, dependent upon whether their video chat rooms are free or private. Viewers in private chat rooms pay the performance by the minute. In free chat rooms, payment is voluntary in the form of tips.
Tips are electronic tokens that viewers can buy from a camming website, and then give to the models during live performances to show appreciation. Tokens can also be used to buy access to private shows, operate a Teledildonic device that a model may be wearing, or buy videos and souvenirs from a model. The website provides the transactional platform and then collects and distributes a percentage of the tips to the models. For public chat rooms, the model's portion of a tip ranges from 30% to 70%, depending on the cam site.
A July 2020 survey found the average webcam model in the United States works 18 hours per week, and earns $4,470 per month. Webcam models who work full-time (40 hours per week or more) earn $11,250 per month on average. Top-earning webcam models have a self-reported income of over $312,000 annually, while bottom earners take home as little as $100 per week.
=== US taxes ===
In the United States, webcam models are considered as self-employed workers, and their tax rate is 15.3% (where 12.4% is for social security and 2.9% for Medicare), plus income tax. If a webcam model earns more than $600 in a year, they are sent a 1099 form and are required to report the income to the IRS.
=== Personal connection and interaction ===
Performances can be interactive in both public and private video chat rooms, as viewers and performers can communicate with each other using a keyboard, speech, and two-way cameras. Within public chat rooms, the audience can see tips and viewer comments as scrolling text next to the real-time video stream. Camgirls will frequently read and respond to the scrolling viewer comments. The chatter is constant and is often led by a small band of regular fans.
This is not the first time conversational interaction has become a boon for the erotic entertainment industry. In the early 20th century, sociologist Paul Cressey noted that within the hundreds of taxi-dance halls of America, "the traffic in romance and feminine society" would become available when taxi dancers would offer their companionship and "the illusion of romance" for ten cents a dance. The Mitchell Brothers O'Farrell Theatre strip club is credited with the invention of the lap dance in 1977 when their new stage, New York Live, pioneered customer-contact shows with strippers that came off the stage and sat in the laps of customers for tips. Enabled with this new revenue stream for strippers, the strip club industry went through a period of extreme growth during the 1980s.
There are often connections between erotic video performance and the everyday social lives of camming customers. Webcam performers are often highly entrepreneurial and use mainstream social networking sites such as Twitter, Instagram, Snapchat, Skype, and Tumblr to build and maintain relationships with their customers. Some fans communicate multiple times a day with models through social media.
Unlike traditional pornography, the interactive nature of the camming medium titillates with the promise of virtual friendship. Princeton University sociologist and author of The Purchase of Intimacy, Viviana Zelizer, states of camming: "they're defining a new kind of intimacy. It's not traditional sex work, not a relationship, but something in between." In addition to performing sex work, cam models also perform through their hosting duties, conveying authenticity, creating and animating fantasies, and managing relationships over time.
Within Cam Girlz, a documentary film about the industry, male fans often say that they come to camming sites as a way to fulfill emotional needs. The film's director, Sean Dunne, states of the fans, "they said it's not like a strip club – it's like a community, and you feel it when you're in these chat rooms. It's a community and entertainment that goes very far beyond sexuality."
However, Dr Kari Lerum of the University of Washington suggests that men are more open and vulnerable in cam rooms than in strip clubs, and can become very invested in relationships which only exist on the screen. This proposition was supported by a 2019 study of over 6,000 webcam users by the webcam platform Stripchat. The study found that over 40% of its users had developed significant relationships with their cam models, ranging from friendship to deep emotional connections.
== Terminology ==
The term webcam is a clipped compound, combining the terms World Wide Web and video camera.
When webcam models create live webcasts, the activity is known as camming. A third-party hosting website which transmits multiple webcam models' video-streams is known as a camming site. Webcam models mostly perform individually in separate video chat rooms, frequently referred to as rooms.
The generally derogatory and pejorative term camwhore was used in print as early as November 2001. While commonly applied to sexually explicit performers, the term has also been applied to non-explicit female livestreamers on platforms such as Twitch and YouTube.
== Camming industry ==
As of 2016, the money generated by camming sites was upwards of US$2 billion annually. The pornography business as a whole is estimated to be about $5 billion. According to the web traffic analysis service Compete.com, LiveJasmin generates more than 9 million unique viewers a month. Similar webcam model hosting sites such as Chaturbate, CAM4, and MyFreeCams boast 4.1 million, 3.7 million and 2 million unique monthly visitors, respectively. Certain hosting sites such as the aforementioned Chaturbate, LiveJasmin, ManyVids, and many other providers also offer payment in cryptocurrency.
The decentralized business model of camming has upended the pornography industry in multiple ways. Camming revenue has been severely cutting into the profits of the pornographic movie business, which has also been eroded for several years by piracy and the distribution of free sexual content on the Internet. The pornographic film industry used to be male-dominated, except for the performers. Since camming requires only a video camera, broadband service, and a computer, there has now been a power reversal, and female webcam performers are driving the industry. Todd Blatt, a former pornographic movie producer, has said, "If you're the middle guy who has been eating off this industry for 20 years, it's a big change. The girls don't need anybody."
The new revolution that the decentralized camming industry has brought also challenged many cultural stereotypes concerning both the camgirls and their customers. Ethnography researcher Dr Theresa Senft became a camgirl for a year while doing four years of research for her 2008 book Camgirls: Celebrity and Community in the Age of Social Networks. Senft has described herself as "the first academic camgirl" while becoming a "camgirl writing about camgirls." Anna Katzen, a camgirl who has a postgraduate degree from Harvard, stated during an interview:
The men I meet online rarely fall into the category of anonymous asses who have abandoned all social etiquette, nor do they resemble the pasty, calculator-wristwatch-wearing forebears of chat rooms past. Many, in fact, are successful professionals in their field – whether it be law, the arts or academia. Some of my most popular performances entail me reading erotica, perhaps Anaïs Nin or the Marquis de Sade, in the buff. Oftentimes, the books are gifts from fans, who will probe me for literary analysis if I don't probe myself with something else first.
Furthermore, she says that:
I have unwittingly created a powerful 'brand' for myself: the wild intellectual, the bluestocking in garters. 'I came for the tits, but stayed for the intellectual banter,' remarked one of my visitors, and another stated, 'most guys aren't looking for some airbrushed Barbie. They want real, intelligent girls – like you.' [emphasis in original, links added]
During the COVID-19 pandemic, the webcamming industry experienced explosive growth. The popular platform OnlyFans reported $2.4 billion in transactions in 2020, a 600% increase from 2019. This was driven in part by a large influx of new creators with little or no previous experience in sex work who joined the platform due to unemployment.
=== Hosting websites ===
Webcam models typically make use of third-party websites to stream their real-time video performances on the Internet. Some sites charge viewers a fixed fee per minute, although many allow free access for unregistered visitors. These Internet hosting websites, known as camming sites, take care of the technical work – hosting the video feed broadcast, processing payments, providing an intuitive interface, advertising – so that the cam model only has to focus on the actual shows for their video chat room.
A fee can be charged for service as a percentage of the revenue made by the model. To improve security and anonymity, some webcamming services (such as Live Stars) use blockchain technology to handle the payment and to protect the model's entered personal information. SpankChain is another similar camming site and cryptocurrency.
By presenting hundreds of different models via individual chat rooms, a camming site becomes a talent aggregator and middleman. Though a camming website may carry many hundreds of models, they frequently provide an interface for the viewer to easily switch between the most-visited models' rooms, and that interface occasionally resembles the multiple channel selection of cable television.
Most cam models are independent contractors for camming sites, and are not employees.
Camming sites typically supply each webcam model with an individual profile webpage where the performer can describe themselves and more importantly, create a virtual store where they can sell items like videos, photos, personal clothing, and memberships to their fan club. The profile page's virtual store creates a stream of passive income, meaning that even if a camgirl is not online and performing, she can still generate money while fans come to the ever-present profile page to purchase its wares. Some of the most popular items are homemade videos cam models make of themselves. While most of these videos are sexual in nature, they often include elements of comedy, fashion, and a narration of their lifestyles.
The affordability of and access to new video recording technology has spawned new variations and genres of pornography since individual women, as well as industry players, can now create content. A profile page might also sell contact information like a personal phone number, a spot on a model's Snapchat contact list, or the ability to send her private messages through a camming site's friends list. The profile page may also suggest tip amounts for real-time performance requests, like a sexy dance, a song request, removal of clothing, or a particular sex act. All prices on a profile page are listed in quantities of tips, which are electronic tokens that the viewer can buy in bunches from the cam site to be given to various models during the performance, or in later purchases upon the profile page.
The camming site keeps a percentage of the tips, and the amount varies. Big earners can get a bigger chunk of their tips. Commissions earned by webcam models vary widely by website and are usually based on a percentage of gross sales, although sometimes they are in the form of a flat fee. They may also earn money through advertising or commissions by persuading customers to sign up for membership at adult pornographic paysites. Many sites encourage viewers to purchase items from online wish lists. Some webcam models cater to particular fetishes, such as a fascination with feet, and might earn additional money by selling worn socks to patrons. Some models will cater to extremely specific fetishes, as customers with uncommon fetishes tend to pay more. This has been criticized as a "race to the bottom," where webcam models will attempt to outdo each other in perversity. In reaction, cam models on websites such as Chaturbate have developed a culture discouraging engagement in fetishes they consider demeaning.
Camming sites specify rules and restrictions for their cam models, which in turn tend to give the camming site a distinct style and format. For example, one major free-access site, which only allows female models, fosters an environment where the camgirls are not necessarily obligated to do masturbation shows or even display nudity. Consequently, some of that site's models create a more relaxed "hangout atmosphere" within their rooms that occasionally resembles a talk show. Conversely, another major cam site, which allows men and couples to perform, tends to be more sexual and show-oriented. On some sites, models are not required to show their face on the webcam stream (thus allowing the use of veils, masks, ...). Other cam site rules might prohibit working in a public place so that the model does not get a public indecency arrest, the way that Kendra Sunderland was charged after her 2014 performance inside the Oregon State University Library. Models who violate a camming site's rules may be subjected to a temporary or permanent ban from the cam site.
=== Social media ===
Webcam models often rely on social media to interact with existing customers and to meet new customers. This has potential disadvantages; however, mainstream social media platforms often have poorly-defined and changing rules that sex workers can inadvertently break. Having a social media account closed for any reason – legitimate or otherwise – can severely affect a performer's ability to earn income.
Some cam models have non-commercial personal web blogs.
=== Resources for performers ===
Cam studios allow models to rent facilities outside of their homes. These businesses can supply models with video equipment, Internet service, computer, lighting, and furniture. One example was the pornographic film company Kink.com, which rented individual cam studios in the San Francisco Armory by the hour from 2013 until the building was sold in 2018.
Within some studios, cam models can work by the percentage of business that they bring in, instead of renting studio time. The cam models do not have to pay to join this type of studio and are also not guaranteed a salary. These models can typically charge customers between $1 and $15 per minute, and then the studio keeps half of the gross while the model gets the rest.
Another workplace option is called a "camgirl mansion", which is a place that provides equipment and broadcast rooms, where multiple camgirls can live and share expenses without a studio owner.
Various support websites supply general information about business strategies, upcoming conferences, performance tips, and studio equipment reviews. Support sites also advise on how to protect privacy, discourage piracy, avoid Internet security lapses, and prevent financial scams. Some chat websites for cam models provide message boards for the models, which enables them to discuss their work concerns and issues, such as clients who get overly attached.
Conferences and industry trade shows can also aid cam models by allowing cam models to network and meet others in the profession on a personal level. Cam model Nikki Night provides a coaching service for cam models, in which she advises them on business practices that maximize revenues.
== Legal issues and risks ==
=== Laws ===
Due to the controversial nature of pornography, camming, like most sex work, is not considered a legitimate form of labor in most developed countries. As a result, cam models do not receive the same benefits and rights as other employees since they are technically independent contractors. This offers cam models some freedom not offered to other laborers but prevents them from demanding better treatment from the websites that host them. However, in-person sex work is treated more harshly since it is illegal in many Western countries, including the United States. Camming is considered slightly different, since it is considered pornography as a virtue of being filmed.
Regulation would be beneficial to camming, since it would prevent cam models from being exploited for their labor. However, regulation could also potentially take away cam models' independence, such as sexual freedom and bodily autonomy. Although in-person sex work such as prostitution can be regulated by policing the streets, online sex work is hard to regulate, due to anonymity, and risk of encroaching on content that is risqué, but not necessarily pornographic. In a study on sex work in East Java, Indonesia where a specific district decriminalized sex work while its surround districts did not, researchers found that anti-prostitution laws decreased the use of condoms, which in effect increased the transmission of sexually transmitted diseases such as HIV.
==== China ====
In accordance with the 1997 penal code, pornography is illegal in China. The law only permits educational or artistic depictions of sexual intercourse. Historically, the law is not interpreted by the government to include pornography under the umbrella of art. As such, camming faces strict regulation on the internet in contrast to Western countries, where its legal distinction protects it from prostitution. However, camming can also be a form of solace for sex workers since it allows them to escape online where they can avoid persecution for their profession.
China has planned to extend anti-camming laws to ASMR. The Chinese government claims that ASMR constitutes pornography, but Chinese ASMR content creators dispute this, arguing that pornographic ASMR represents a different category from non-sexual ASMR.
==== India ====
Sex work is legal in India, but many related elements such as brothels are illegal. Thus, camming is legal in India, but a social stigma remains. There is a narrative that sex workers in India are coerced into their profession, but this is not true of all sex workers. Many sex workers attest that their profession is legitimate labor and should be recognized as such. Due to the illegality of pimping, sex workers like cammers tend to operate independently and thus control their labor and profits.
==== Philippines ====
Sex work is illegal in the Philippines, but enforcement of the law is not strict such that it is quite commonplace. There is a perception that Filipino sex workers are victims of human trafficking, but this isn't always the case. Camming, in particular, is usually consensual and not always explicitly sexual, likening it more to performance than pornography.
==== United Kingdom ====
Sex work and camming in the United Kingdom is heavily regulated by the government. Sex work is not recognized as legitimate employment by the government. As a result, sex workers are often afraid to report crimes committed against them, making sex work a dangerous occupation. Sex workers, both online and offline, are often subject to stalking, unwanted messages, and other forms of harassment. It is hard to obtain concrete conclusions from studies on sex work in the UK due to its tenuous legality. Most studies are conducted through surveys which are subject to biases.
A sex work researcher, Rachel Stuart, notes a paradox in British law that tends to focus on the uploading of pornographic recordings, but does not deal with erotic performance when streamed upon the Internet through camming. For instance, the Audiovisual Media Services Regulations 2014 ban certain acts from being depicted and uploaded by pornography producers in the United Kingdom, and the Digital Economy Act 2017 seeks to restrict minors' access to pornographic material online, yet both laws will have no effect if the performances are streamed as opposed to recorded. Stuart states of the legal conundrum in England, "Performing an explicitly pornographic act via a webcam carries no repercussions, but if the same show is recorded and uploaded, the performer can be liable to a fine."
==== United States ====
Lawrence Walters, a Florida lawyer who is an expert in obscenity law, said that there was nothing inherently illegal about web model camming shows, as long as the models were over 18, and performed at home or in a model's studio.
=== Risks ===
While the conduct of webcam models' clients in chat rooms has been described as generally civil and polite, some models have faced "aggressive sexual language" and online harassment. In 2012, a group of 4chan users harassed a webcam model about her weight until she began crying on camera. Even clients who are polite can behave in ways that make models feel uncomfortable, such as when clients become overly attached to, or obsessive, about a model; if the client is a regular customer and a heavy tipper, this can make the model feel pressured to give in to the client's requests. Webcam models have occasionally been the targets of cyber-stalkers and blackmailers. Some cam models have been "blackmailed or threatened into performing acts they are not comfortable with. If they don't comply, they run the risk of having their real identity exposed". In one case, Internet trolls revealed the real name, address and phone number of a webcam performer and posted this information, along with explicit photos of her, on social media, and the account was forwarded to her friends and family. As of 2019, it was reported that there is little legal protection for cam models, as most of the case law deals with the regulation of strip clubs and sex shops, or for distribution of products.
Sex work researcher, Rachel Stuart, reported that while doing her PhD research she encountered webcam models who were concerned about viewers filming and sharing their performances on porn sites, or acquiring personal information which could be used to stalk or blackmail them. In 2013, the New York Times interviewed a woman who prefers to conceal her real identity while working as a camgirl. She revealed that she had been cyber-stalked by a heavy tipper who started making threats and demands about what outfits she should wear. A short while later, she found out that her real name and address had been posted on the Internet along with her cam name. When she complained to the police, they said that they could do nothing, because "putting real information on the Internet is not illegal." She later found out that the same individual had also threatened and outed several other camgirls.
Another issue faced by cam models is that viewers may record streams or images of the model without their consent and then redistribute them on pornography websites. In addition to taking away the model's ability to choose where their content is shown, unauthorized use has been likened to theft of the model's property, since the porn site will earn money from the video and not the cam model.
Sex workers have formed support groups where sex workers may give each other advice and possibly cope with harassment and marginalization. The word "camily", a portmanteau of "cam" and "family", refers to communities formed by sex workers to help deal with such issues.
=== Incidents ===
==== 1990s ====
A New York Times report described the story of Justin Berry, a 13-year-old boy who, after hooking up his webcam and listing himself on an online forum in order to make friends, was propositioned by older men to strip and masturbate on camera. CNN referred to him as "in the language of cyberspace... a cam-whore". He started his own paysite, prostituted himself, sold video recordings of his encounters with Mexican prostitutes, and helped hire other underage models. He made several hundred thousand dollars over five years before turning all information over to prosecutors in exchange for immunity.
==== 2010s ====
In October 2014, a 19-year-old Oregon State University student, Kendra Sunderland, had been working as a camgirl before she made an hour-long video for MyFreeCams.com of herself at the Oregon State University Library, in which she stripped and masturbated on camera for a live audience. She was then charged with public indecency after the show was recorded by someone who was watching MyFreeCams.com online, and then posted it on other sites. Sunderland faced fines up to $6,250 and one year of jail. She pleaded guilty, paid $1,000, and avoided jail. The incident generated headlines around the country and landed Sunderland reported deals with Playboy, and a contract with Penthouse's parent company Friend Finder Networks purportedly worth six figures. The incident greatly increased Sunderland's popularity, and she has continued to do camming and speak positively of it as a career.
In Arizona during 2015, a fan took his appreciation of camgirls to an illegal level when he was indicted for spending $476,000 on a company credit card, which he used for tips on camming websites. He spent more than $100,000 on MyFreeCams.com alone, and sent $26,800 to one cam model in particular to pay for her college tuition bill and new tires for her car. According to the indictment, he also purchased flowers, chocolates, electronic equipment, shoes, a TV, a handbag, laptop computer, and an iPod for some of his favorite camgirls.
In one case, sex traffickers who operated illegal brothels forced an indentured victim to have sex in webcam shows.
In January 2019, a 29-year-old Grant Amato killed his father, mother and brother and staged the scene as a murder-suicide, placing the gun by his brother's body. His motivation was an argument with his parents about his infatuation with a webcam model.
== See also ==
== References ==
== Further reading ==
Jones, Angela (Autumn 2016). "'I Get Paid to Have Orgasms': Adult Webcam Models' Negotiation of Pleasure and Danger". Signs: Journal of Women in Culture and Society. 42 (1): 227–256. doi:10.1086/686758. S2CID 151749909.
Jade, Jasmine (2015). Camgirl Manual. Metal Motion Productions Incorporated. ISBN 9780993608704.
Senft, Theresa M. (2008). Camgirls: Celebrity and Community in the Age of Social Networks. Peter Lang. ISBN 9780820456942.
Wall, David (2007). Cybercrime: The Transformation of Crime in the Information Age. Polity. ISBN 9780745627359.
Bocij, Paul (2004). Cyberstalking: Harassment in the Internet Age and how to Protect Your Family. Greenwood Publishing Group. ISBN 9780275981181.
== External links ==
Media related to Webcam models at Wikimedia Commons | Wikipedia/Webcam_model |
Fertility awareness (FA) refers to a set of practices used to determine the fertile and infertile phases of a woman's menstrual cycle. Fertility awareness methods may be used to avoid pregnancy, to achieve pregnancy, or as a way to monitor gynecological health.
Methods of identifying infertile days have been known since antiquity, but scientific knowledge gained during the past century has increased the number, variety, and especially accuracy of methods.
Systems of fertility awareness rely on observation of changes in one or more of the primary fertility signs (basal body temperature, cervical mucus, and cervical position), tracking menstrual cycle length and identifying the fertile window based on this information, or both. Other signs may also be observed: these include breast tenderness and mittelschmerz (ovulation pains), urine analysis strips known as ovulation predictor kits (OPKs), and microscopic examination of saliva or cervical fluid. Also available are computerized fertility monitors.
== Terminology ==
Symptoms-based methods involve tracking one or more of the three primary fertility signs: basal body temperature, cervical mucus, and cervical position. Systems relying exclusively on cervical mucus include the Billings Ovulation Method, the Creighton Model, and the Two-Day Method. Symptothermal methods combine observations of basal body temperature (BBT), cervical mucus, and sometimes cervical position. Calendar-based methods rely on tracking a woman's cycle and identifying her fertile window based on the lengths of her cycles. The best known of these methods is the Standard Days Method. The Calendar-Rhythm method is also considered a calendar-based method, though it is not well defined and has many different meanings to different people.
Systems of fertility awareness may be referred to as fertility awareness–based methods; the term Fertility Awareness Method (FAM) refers specifically to the system taught by Toni Weschler. The term natural family planning is sometimes used to refer to any use of fertility awareness methods, the lactational amenorrhea method and periodic abstinence during fertile times. A method of fertility awareness may be used by natural family planning users to identify these fertile times.
Women who are breastfeeding a child and wish to avoid pregnancy may be able to practice the lactational amenorrhea method. The lactational amenorrhea method is distinct from fertility awareness, but because it also does not involve contraceptives, it is often presented alongside fertility awareness as a method of "natural" birth control.
Within the Catholic Church and some Protestant denominations, the term natural family planning is often used to refer to Fertility Awareness pointing out it is the only method of family planning approved by the Church.
== History ==
=== Development of calendar-based methods ===
It is not known exactly when it was first discovered that women have predictable periods of fertility and infertility. It is already clearly stated in the Talmud tractate Niddah, that a woman only becomes pregnant in specific periods in the month, which seemingly refers to ovulation. St. Augustine wrote about periodic abstinence to avoid pregnancy in the year 388 (the Manichaeans attempted to use this method to remain childfree, and Augustine condemned their use of periodic abstinence). One book states that periodic abstinence was recommended "by a few secular thinkers since the mid-nineteenth century," but the dominant force in the twentieth century popularization of fertility awareness-based methods was the Roman Catholic Church.
In 1905 Theodoor Hendrik van de Velde, a Dutch gynecologist showed that women only ovulate once per menstrual cycle. In the 1920s, Kyusaku Ogino, a Japanese gynecologist, and Hermann Knaus, from Austria, independently discovered that ovulation occurs about fourteen days before the next menstrual period. Ogino used his discovery to develop a formula for use in aiding infertile women to time intercourse to achieve pregnancy. In 1930, John Smulders, a Roman Catholic physician from the Netherlands, used this discovery to create a method for avoiding pregnancy. Smulders published his work with the Dutch Roman Catholic medical association, and this was the first formalized system for periodic abstinence: the rhythm method.
=== Introduction of temperature and cervical mucus signs ===
In the 1930s, Reverend Wilhelm Hillebrand, a Catholic priest in Germany, developed a system for avoiding pregnancy based on basal body temperature. This temperature method was found to be more effective at helping women avoid pregnancy than were calendar-based methods. Over the next few decades, both systems became widely used among Catholic women. Two speeches delivered by Pope Pius XII in 1951 gave the highest form of recognition to the Catholic Church's approval—for couples who needed to avoid pregnancy—of these systems. In the early 1950s, John Billings discovered the relationship between cervical mucus and fertility while working for the Melbourne Catholic Family Welfare Bureau. Billings and several other physicians, including his wife, Dr. Evelyn Billings, studied this sign for a number of years, and by the late 1960s had performed clinical trials and begun to set up teaching centers around the world.
=== First symptoms-based teaching organizations ===
While Dr. Billings initially taught both the temperature and mucus signs, they encountered problems in teaching the temperature sign to largely illiterate populations in developing countries. In the 1970s they modified the method to rely on only mucus. The international organization founded by Dr. Billings is now known as the World Organization Ovulation Method Billings.
The first organization to teach a symptothermal method was founded in 1971. John and Sheila Kippley, lay Catholics, joined with Dr. Konald Prem in teaching an observational method that relied on all three signs: temperature, mucus, and cervical position. Their organization is now called Couple to Couple League International. The next decade saw the founding of other now-large Catholic organizations, Family of the Americas (1977), teaching the Billings method, and the Pope Paul VI Institute (1985), teaching a new mucus-only system called the Creighton Model.
Up until the 1980s, information about fertility awareness was only available from Catholic sources. The first secular teaching organization was the Fertility Awareness Center in New York, founded in 1981. Toni Weschler started teaching in 1982 and published the bestselling book Taking Charge of Your Fertility in 1995. Justisse was founded in 1987 in Edmonton, Canada. These secular organizations all teach symptothermal methods. Although the Catholic organizations are significantly larger than the secular fertility awareness movement, independent secular teachers have become increasingly common since the 1990s.
=== Ongoing development ===
Development of fertility awareness methods is ongoing. In the late 1990s, the Institute for Reproductive Health at Georgetown University introduced two new methods. The TwoDay Method, a mucus-only system, and CycleBeads and iCycleBeads (the digital version), based on the Standard Days Method, are designed to be both effective and simple to teach, learn, and use. In 2019, Urrutia et al. released a study as well as interactive graph over-viewing all studied fertility awareness based methods. Femtech companies such as Dot and Natural Cycles have also produced new studies and apps to help women avoid pregnancy. Natural Cycles is the first app of its kind to receive FDA approval.
== Fertility signs ==
Most menstrual cycles have several days at the beginning that are infertile (pre-ovulatory infertility), a period of fertility, and then several days just before the next menstruation that are infertile (post-ovulatory infertility). The first day of red bleeding is considered day one of the menstrual cycle. Different systems of fertility awareness calculate the fertile period in slightly different ways, using primary fertility signs, cycle history, or both.
== Primary fertility signs ==
The three primary signs of fertility are basal body temperature (BBT), cervical mucus, and cervical position. A woman practicing symptoms-based fertility awareness may choose to observe one sign, two signs, or all three. Many women experience secondary fertility signs that correlate with certain phases of the menstrual cycle, such as abdominal pain and heaviness, back pain, breast tenderness, and mittelschmerz (ovulation pains).
=== Basal body temperature ===
This usually refers to a temperature reading collected when a person first wakes up in the morning (or after their longest sleep period of the day). The true BBT can only be obtained by continuous temperature monitoring through internally worn temperature sensors. In women, ovulation will trigger a rise in BBT between 0.2º and 0.5 °C. (0.5 and 1.°F) that lasts approximately until the next menstruation. This temperature shift may be used to determine the onset of post-ovulatory infertility. (See ref. 30)
=== Cervical mucus ===
The appearance of cervical mucus and vulvar sensation are generally described together as two ways of observing the same sign. Cervical mucus is produced by the cervix, which connects the uterus to the vaginal canal. Fertile cervical mucus promotes sperm life by decreasing the acidity of the vagina, and also it helps guide sperm through the cervix and into the uterus. The production of fertile cervical mucus is caused by estrogen, the same hormone that prepares a woman's body for ovulation. By observing her cervical mucus and paying attention to the sensation as it passes the vulva, a woman can detect when her body is gearing up for ovulation, and also when ovulation has passed. When ovulation occurs, estrogen production drops slightly and progesterone starts to rise. The rise in progesterone causes a distinct change in the quantity and quality of mucus observed at the vulva.
=== Cervical position ===
The cervix changes position in response to the same hormones that cause cervical mucus to be produced and to dry up. When a woman is in an infertile phase of her cycle, the cervix will be low in the vaginal canal; it will feel firm to the touch (like the tip of a person's nose); and the os—the opening in the cervix—will be relatively small, or "closed". As a woman becomes more fertile, the cervix will rise higher in the vaginal canal, it will become softer to the touch (more like a person's lips), and the os will become more open. After ovulation has occurred, the cervix will revert to its infertile position.
== Cycle history ==
Calendar-based systems determine both pre-ovulatory and post-ovulatory infertility based on cycle history. When used to avoid pregnancy, these systems have higher perfect-use failure rates than symptoms-based systems but are still comparable with barrier methods, such as diaphragms and cervical caps.
Mucus- and temperature-based methods used to determine post-ovulatory infertility, when used to avoid conception, result in very low perfect-use pregnancy rates. However, mucus and temperature systems have certain limitations in determining pre-ovulatory infertility. A temperature record alone provides no guide to fertility or infertility before ovulation occurs. Determination of pre-ovulatory infertility may be done by observing the absence of fertile cervical mucus; however, this results in a higher failure rate than that seen in the period of post-ovulatory infertility. Relying only on mucus observation also means that unprotected sexual intercourse is not allowed during menstruation, since any mucus would be obscured.
The use of certain calendar rules to determine the length of the pre-ovulatory infertile phase allows unprotected intercourse during the first few days of the menstrual cycle while maintaining a very low risk of pregnancy. With mucus-only methods, there is a possibility of incorrectly identifying mid-cycle or anovulatory bleeding as menstruation. Keeping a basal body temperature chart enables accurate identification of menstruation, when pre-ovulatory calendar rules may be reliably applied. In temperature-only systems, a calendar rule may be relied on alone to determine pre-ovulatory infertility. In symptothermal systems, the calendar rule is cross-checked by mucus records: observation of fertile cervical mucus overrides any calendar-determined infertility.
Calendar rules may set a standard number of days, specifying that (depending on a woman's past cycle lengths) the first three to six days of each menstrual cycle are considered infertile. Or, a calendar rule may require calculation, for example holding that the length of the pre-ovulatory infertile phase is equal to the length of a woman's shortest cycle minus 21 days. Rather than being tied to cycle length, a calendar rule may be determined from the cycle day on which a woman observes a thermal shift. One system has the length of the pre-ovulatory infertile phase equal to a woman's earliest historical day of temperature rise minus seven days.
== Other techniques ==
Ovulation predictor kits can detect imminent ovulation from the concentration of luteinizing hormone (LH) in a woman's urine. A positive ovulation predictor kit result is usually followed by ovulation within 12–36 hours.
Saliva microscopes, when correctly used, can detect ferning structures in the saliva that precede ovulation. Ferning is usually detected beginning three days before ovulation, and continuing until ovulation has occurred. During this window, ferning structures occur in cervical mucus as well as saliva.
Computerized fertility monitors, such as Lady-Comp, are available under various brand names. These monitors may use BBT-only systems, they may analyze urine test strips, they may use symptothermal observations, they may monitor the electrical resistance of saliva and vaginal fluids, or a combination of any of these factors.
A symptohormonal method of fertility awareness method developed at Marquette University uses the ClearBlue Easy fertility monitor to determine the fertile window. The monitor measures estrogen and LH to determine the peak day. This method is also applicable during postpartum, breastfeeding, and perimenopause, and requires less abstinence than other fertility awareness method methods. Some couples prefer this method because the monitor reading is objective and is not affected by sleep quality as basal body temperature can be.
== Benefits and drawbacks ==
Fertility awareness has a number of unique characteristics:
Fertility awareness can be used to monitor reproductive health. Changes in the cycle can alert the user to emerging gynecological problems. Fertility awareness can also be used to aid in diagnosing known gynecological problems such as infertility.
Fertility awareness may be used to avoid pregnancy or to aid in conception.
Use of fertility awareness can give insight to the workings of women's bodies, and may allow women to take greater control of their own fertility.
Some symptoms-based forms of fertility awareness require observation or touching of cervical mucus, an activity with which some women are not comfortable. Some practitioners prefer to use the term "cervical fluid" to refer to cervical mucus, in an attempt to make the subject more acceptable to these women.
Some drugs, such as decongestants, can change cervical mucus. In women taking these drugs, the mucus sign may not accurately indicate fertility.
Some symptoms-based methods require tracking of basal body temperatures. Because irregular sleep can interfere with the accuracy of basal body temperatures, shift workers and those with very young children, for example, might not be able to use those methods.
FA requires action daily—detailed record keeping. Some may find the time and detail requirements too complicated.
== As birth control ==
By restricting unprotected sexual intercourse to the infertile portion of the menstrual cycle, a woman and her partner can prevent pregnancy. During the fertile portion of the menstrual cycle, the couple may use barrier contraception or abstain from sexual intercourse.
=== Advantages ===
There are no drug-related side effects to fertility awareness.
FA can be free or have a very low up-front cost. Users may employ a coach, use computer software, or buy a chart, calendar, or basal thermometer. The direct costs are low when compared to other methods.
FA can be used with barrier contraception so that intercourse may continue through the fertile period. Unlike barrier use without FA, practicing FA can allow couples to use barrier contraception only when necessary.
FA can be used to immediately switch from pregnancy avoidance to pregnancy planning if the couple decides it is time to plan for conception.
=== Disadvantages ===
Use of a barrier or other backup method is required on fertile days; otherwise the couple must abstain. To reduce pregnancy risk to below 1% per year, there are an average of 13 days where abstinence or backup must be used during each cycle. For women with very irregular cycles—such as those common during breastfeeding, perimenopause, or with hormonal diseases such as PCOS—abstinence or the use of barriers may be required for months at a time.
Typical use effectiveness is lower than most other methods.
Fertility awareness does not protect against sexually transmitted disease.
=== Effectiveness ===
The effectiveness of fertility awareness, as of most forms of contraception, can be assessed two ways. Perfect use or method effectiveness rates only include people who follow all observational rules, correctly identify the fertile phase, and refrain from unprotected intercourse on days identified as fertile. Actual use or typical use effectiveness rates include all women relying on fertility awareness to avoid pregnancy, including those who fail to meet the "perfect use" criteria. Rates are generally presented for the first year of use. Most commonly, the Pearl Index is used to calculate effectiveness rates, but some studies use decrement tables.
The failure rate of fertility awareness varies widely depending on the system used to identify fertile days, the instructional method, and the population being studied. Some studies have found actual failure rates of 25% per year or higher. At least one study has found a failure rate of less than 1% per year with continuous intensive coaching and monthly review, and several studies have found actual failure rates of 2%–3% per year.
When used correctly and consistently (i.e., with perfect use) with ongoing coaching, under study conditions some studies have found some forms of FA to be 99% effective.
From Contraceptive Technology:
Post-ovulation methods (i.e., abstaining from intercourse from menstruation until after ovulation) have a method failure rate of 1% per year.
The symptothermal method has a method failure rate of 2% per year.
Cervical mucus–only methods have a method failure rate of 3% per year.
Calendar rhythm has a method failure rate of 9% per year.
The Standard Days Method has a method failure rate of 5% per year.
=== Reasons for lower typical-use effectiveness ===
Several factors account for typical-use effectiveness being lower than perfect-use effectiveness:
conscious user non-compliance with instructions (having unprotected intercourse on a day identified as fertile)
mistakes on the part of those providing instructions on how to use the method (instructor providing incorrect or incomplete information on the rule system)
mistakes on the part of the user (misunderstanding of rules, mistakes in charting)
The most common reason for the lower actual effectiveness is not mistakes on the part of instructors or users, but conscious user non-compliance—that is, the couple knowing that the woman is likely to be fertile at the time but engaging in sexual intercourse nonetheless. This is similar to failures of barrier methods, which are primarily caused by non-use of the method.
== To achieve pregnancy ==
=== Intercourse timing ===
Timing intercourse with a person's estimated 'fertile window' is a practice sometimes called 'timed intercourse'. The effectiveness of timed intercourse is not entirely clear, however, timed intercourse using urine tests that predict ovulation may help improve the rate of pregnancy and live births for some couples trying to conceive such as those who have been trying for less than 12-months and who are under 40 years old. It is not clear from medical evidence if timed intercourse improves the rate of ultra-sound confirmed pregnancies and it is also not clear if timed intercourse has an effect on a person's level of stress or their quality of life. Pregnancy rates for sexual intercourse are also affected by several other factors. Regarding frequency, there are recommendations of sexual intercourse every 1 or 2 days, or every 2 or 3 days. Studies have shown no significant difference between different sex positions and pregnancy rate, as long as it results in ejaculation into the vagina. Social science research has found that timing intercourse can become a gendered 'chore' in heterosexual married couples trying to conceive, with women tracking their ovulation cycles and dictating to their husbands when they should have sexual intercourse.
=== Problem diagnosis ===
Regular menstrual cycles are sometimes taken as evidence that a woman is ovulating normally, and irregular cycles as evidence she is not. However, many women with irregular cycles do ovulate normally, and some with regular cycles are actually anovulatory or have a luteal phase defect. Records of basal body temperatures, especially, but also of cervical mucus and position, can be used to accurately determine if a woman is ovulating, and if the length of the post-ovulatory (luteal) phase of her menstrual cycle is sufficient to sustain a pregnancy.
Fertile cervical mucus is important in creating an environment that allows sperm to pass through the cervix and into the fallopian tubes where they wait for ovulation. Fertility charts can help diagnose hostile cervical mucus, a common cause of infertility. If this condition is diagnosed, some sources suggest taking guaifenesin in the few days before ovulation to thin out the mucus.
=== Pregnancy testing and gestational age ===
Pregnancy tests are not accurate until 1–2 weeks after ovulation. Knowing an estimated date of ovulation can prevent a woman from getting false negative results due to testing too early. Also, 18 consecutive days of elevated temperatures means a woman is almost certainly pregnant. Estimated ovulation dates from fertility charts are a more accurate method of estimating gestational age than the traditional pregnancy wheel or last menstrual period (LMP) method of tracking menstrual periods. Because of high rates of very early miscarriage (25% of pregnancies are lost within the first six weeks since the woman's last menstrual period), the methods used to detect pregnancy may lead to bias in conception rates. Less-sensitive methods will detect lower conception rates, because they miss the conceptions that resulted in early pregnancy loss.
== See also ==
Billings ovulation method
Creighton Model FertilityCare System
Fertility monitor
Lactational amenorrhea method
Kindara
TwoDay Method
== References ==
== Further reading ==
Toni Weschler (2006). Taking Charge of Your Fertility (10th Anniversary ed.). New York: Collins. ISBN 0-06-088190-9.
John F. Kippley; Sheila K. Kippley (1996). The Art of Natural Family Planning (Fourth ed.). Cincinnati, OH: Couple to Couple League International. ISBN 0-926412-13-2. | Wikipedia/Fertility_awareness_methods |
The PLISSIT model, also known as the PLISSIT model of sex therapy, is a modeling system used in the field of sexology to determine the different levels of intervention for individual clients. The model was created in 1976 by Jack S. Annon. The letters of the name refer to the four different levels of intervention that a sexologist can apply: permission (P), limited information (LI), specific suggestions (SS), and intensive therapy (IT). The model is also used outside the field of sexology, especially in fields involving extensive or life-threatening surgery.
== Structure ==
The model created by Annon has four levels of increasing intervention and interaction related to what kind of and how much help is given to a client. The varying levels largely revolve around what the client is looking for and how comfortable they are in discussing sexuality and sexual health.
The first level is permission, which involves the sexologist giving the client permission to feel comfortable about a topic or permission to change their lifestyle or to get medical assistance. This level was created because many clients only require the permission to speak and voice their concerns about sexual issues in order to understand and move past them, often without needing the other levels of the model. The sexologist, in acting as a receptive, nonjudgmental listening partner, allows the client to discuss matters that would otherwise be too embarrassing for the individual to discuss.
The second level is limited information, wherein the client is supplied with limited and specific information on the topics of discussion. Because there is a significant amount of information available, sexologists must learn what sexual topics the client wishes to discuss, so that information, organizations, and support groups for those specific subjects can be provided.
The third level is specific suggestions, where the sexologist gives the client suggestions related to the specific situations and assignments to do in order to help the client fix the mental or health problem. This can include suggestions on how to deal with sex related diseases or information on how to better achieve sexual satisfaction by the client changing their sexual behavior. The suggestions may be as simple as recommending exercise or can involve specific regimens of activity or medications.
The fourth and final level is intensive therapy, which has the sexologist refer the client to other mental and medical health professionals that can help the client deal with the deeper, underlying issues and concerns being expressed. This level, with the onset of the internet age, may also refer to a sexologist suggesting professional online resources for the client to browse about their specific issue in a more private setting.
=== EX-PLISSIT model ===
The PLISSIT model was extended in 2006 by Sally Davis and Bridget Taylor because of concerns that practitioners often bypass permission-giving and go straight to providing information (sometimes merely in the form of a leaflet), without giving patients the opportunity to express any concerns they might have. The extended model, named the EX-PLISSIT model, places permission-giving at the core. By giving people explicit permission to discuss any concerns they have about their sexuality, the healthcare professional affirms the individual as a sexual being. Any information or suggestions that follow, are then specific to the needs of that person.
The EX-PLISSIT model also requires further permission-giving in the form of 'review', whereby the healthcare professional asks the patient to review the interaction and is given the opportunity to express any further worries or concerns. In addition, this model requires the professional to reflect on their interactions, challenging assumptions and extending their knowledge.
== References ==
== Further reading ==
Annon, Jack S. (1975) The Behavioral Treatment of Sexual Problems. Vol 1: Brief Therapy. Harper & Row
Annon, Jack S. (1976) The Behavioral Treatment of Sexual Problems Vol. 2: Intensive Therapy. Harper & Row | Wikipedia/PLISSIT_model |
Religious adherents vary widely in their views on birth control (also known as contraception). This can be true even between different branches of one faith, as in the case of Judaism and Christianity. Some religious believers find that their own opinions of the use of birth control differ from the beliefs espoused by the leaders of their faith, and many grapple with the ethical dilemma of what is conceived as "correct action" according to their faith, versus personal circumstance, reason, and choice. This article will discuss various views on birth control of the major world religions Christianity, Buddhism, Judaism, Islam, Hinduism, and Baha'i.
The question of whether contraception is a viable option for participants has a range of different beliefs and arguments, which depend on the religion's views on when life begins, and questions of a God or deity's will for human reproduction. Modern arguments for the woman's health are also considered in many religions as a basis for birth control use.
== Christianity ==
Among Christian denominations today there are a large variety of positions towards contraception that range from the acceptance of birth control to only allowing natural family planning to teaching Quiverfull doctrine, which holds that Christians should have large families. The Catholic Church has historically taught against artificial contraception. The Orthodox Church does permit their use. Contraception was taught against by non-Catholic Christians until 1930 when the Anglican Communion changed its policy. Soon after, according to Flann Campbell, mainline Protestant groups came to accept the use of modern contraceptives as a matter of what they considered Biblically allowable freedom of conscience. Conservative Protestants hold any one of the three aforementioned positions (acceptance of birth control, natural family planning, or Quiverfull) depending on the denomination.
=== Roman Catholicism ===
The Catholic Church is opposed to artificial contraception but supports the use of natural cycles to regulate births. This belief dates back to the first centuries of Christianity. Artificial contraception is taught to not fulfill the ideal of married love, while methods such as natural family planning (NFP) are in full accordance with Christian doctrine.
Pope Pius XI explicitly condemned birth control in his 1930 encyclical Casti connubii, stating:No reason, however grave, can make what is intrinsically contrary to nature to be in conformity with nature and morally right. And since the conjugal act by its very nature is destined for the begetting of children, those who in exercising it deliberately frustrate its natural power and purpose are acting against nature, and are doing something that is base and intrinsically immoral".[...] The Catholic Church [...] raises her voice as a sign of her divine mission, and through Our mouth proclaims anew: any use of marriage exercised in such a way that through human effort the act is deprived of its natural power to procreate human life violates the law of God and of nature, and those who commit such an action are stained with the guilt of grave sin.Pope Paul VI confirmed this teaching in his 1968 encyclical Humanae vitae. The following explains:
Therefore We base Our words on the first principles of a human and Christian doctrine of marriage when We are obliged once more to declare that the direct interruption of the generative process has already begun and, above all, all direct abortion, even for therapeutic reasons, are to by excluded as lawful means of regulating the number of children. Equally to be condemned, as the magisterium of the Church has affirmed on many occasions, is direct sterilization, whether of the man of the woman, whether permanent or temporary.
Similarly excluded is any action which either before, at the moment of, or after sexual intercourse, is specifically intended to prevent procreation—whether as an end or as a means.Several other documents provide more insight into the Church's position on contraception. The commission appointed to study the question in the years leading up to Humanae Vitae issued two unofficial reports, a so-called "majority report" which described reasons the Catholic Church should change its teaching on contraception, signed by 61 of 64 scholars assigned to the pontifical commission, and a "minority report" which reiterated the reasons for upholding the traditional Catholic view on contraception. In 1997, the Vatican released a document entitled "Vademecum for Confessors" (2:4) which states "[t]he Church has always taught the intrinsic evil of contraception." Furthermore, many Church Fathers condemned the use of contraception.
Pope Francis in his apostolic exhortation Amoris laetitia repeats Catholic teaching and gives guidance in its interpretation. "The complexity of the issues that arose revealed the need for continued open discussion of a number of doctrinal, moral, spiritual, and pastoral questions." He also continues with a warning that: "The debates carried on in the media, in certain publications and even among the Church’s ministers, range from an immoderate desire for total change without sufficient reflection or grounding, to an attitude that would solve everything by applying general rules or deriving undue conclusions from particular theological considerations." The Pope finishes this with "Since 'time is greater than space', I would make it clear that not all discussions of doctrinal, moral or pastoral issues need to be settled by interventions of the magisterium. Unity of teaching and practice is certainly necessary for the Church, but this does not preclude various ways of interpreting some aspects of that teaching or drawing certain consequences from it. This will always be the case as the Spirit guides us towards the entire truth."
The 1987 document Donum vitae opposes in-vitro fertilization because it is harmful to embryos and separates procreation from the union of the spouses. Later on, the 2008 instruction Dignitas personae denounces embryonic manipulations and new methods of contraception.
Roderick Hindery reported that several Western Catholics have voiced significant disagreement with the Church's stance on contraception. Among them, dissident theologian Charles Curran criticized the stance of Humanae vitae on artificial birth control. In 1968, the Canadian Conference of Catholic Bishops issued what many interpreted as a dissenting document, the Winnipeg Statement, in which the bishops recognized that a number of Canadian Catholics found it "either extremely difficult or even impossible to make their own all elements of this doctrine" (that of Humanae vitae). Additionally, in 1969, they reasserted the Catholic principle of primacy of conscience, a principle that they said should be properly interpreted. They insisted that "a Catholic Christian is not free to form his conscience without consideration of the teaching of the Magisterium, in the particular instance exercised by the Holy Father (i.e., Pope) in an encyclical letter". According to the American Enterprise Institute, 78% of American Catholics say they believe the Church should allow Catholics to use birth control, though other polls reflect different numbers.
According to Stephen D. Mumford, the Vatican's opposition towards birth control continues to this day and has been a major influence on United States policies concerning the problem of population growth and unrestricted access to birth control.
However, in December 2018, in a responsum (a reply by a Curial department that is intended to settle a question or dispute, but that is not a papal document), the Congregation for the Doctrine of the Faith (CDF), under its Prefect, Cardinal Luis Ladaria Ferrer , stated that if the uterus can be found, with moral certainty, to not be able to ever carry a fertilized ovum to the point of viability, that a hysterectomy could be performed because under that very narrow circumstance, it is considered the removal of a failed organ and not per se sterilization since viability is not possible. If a hysterectomy is only done under this circumstance, it does not represent a shift in church teaching.
In July 2023, Pope Francis sent a message to a Natural Family Planning conference in which he upheld the central teachings of Humanae Vitae, warning Catholics that the widespread use of contraception had impoverished many societies and that some countries were now in danger of demographic collapse.
Despite the Church's teaching on contraception, spacing out births by natural means is a behavior that remains in full communion with the Church. Many married couples employ natural family planning (NFP) Studies show a correlation between the practice of NFP and healthy spousal relationships in married couples who utilize this practice. Regardless of the Church's ideas about contraception, 99% of Catholics have used some type of contraception. About one quarter of Catholics use sterilization, 25% use hormonal birth control methods such as birth control pills and 15% have used a long-acting reversible form of birth control such as the IUD.
=== Mainline Protestantism ===
Author and FamilyLife Today radio host Dennis Rainey suggests four categories as useful in understanding current Protestant attitudes concerning birth control. These are the "children in abundance" group, such as Quiverfull adherents who view all birth control and natural family planning as wrong; the "children in managed abundance" group, which accepts only natural family planning; the "children in moderation" group which accepts prudent use of a wide range of contraceptives; and, the "no children" group which sees itself as within their Biblical rights to define their lives around non-natal concerns.
Meanwhile, some Protestant movements, such as Focus on the Family, view contraception used outside of marriage as an encouragement to promiscuity. The Waldensian Evangelical Church believes birth control is acceptable.
Sex is a powerful drive, and for most of human history, it was firmly linked to marriage and childbearing. Only relatively recently has the act of sex commonly been divorced from marriage and procreation. Modern contraceptive inventions have given many an exaggerated sense of safety and prompted more people than ever before to move sexual expression outside the marriage boundary.
==== Anglican/ Episcopalian Views ====
The Anglican Church in 1930 at the Lambeth conference said contraception is acceptable in certain cases.
=== Eastern Orthodoxy and Oriental Orthodoxy ===
The Greek Orthodox Archdiocese of America "permits the use of certain contraceptive practices within marriage to space children, enhance the expression of marital love and protect health."
The Russian Orthodox Church allows for the use of birth control as long as it does not fall under the class of abortifacients.
=== Mormonism ===
In the largest denomination of Mormonism the Church of Jesus Christ of Latter-day Saints (LDS Church), teachings on birth control have change throughout of its history going from condemning it as sinful to allowing it.: 16, 30, 33 The current church stance as of 2023 is that "decisions about birth control and the consequences of those decisions rest solely with each married couple" and that they should consider "the physical and mental health of the mother and father and their capacity to provide the basic necessities of life for their children" when planning a family.
== Hinduism ==
Some Hindu scriptures include advice on what a couple should do to promote conception—thus providing contraceptive advice to those who want it. Rishi Charaka, the father of Ayurveda, has advised various methods of contraceptives based on the physiology of reproduction. Methods like Safe Period, Anti-implantation agents, Inhibition of Ovulation or Spermatogenesis, Intrauterine contraceptive device, Antizygotic drugs, etc. are hinted at in the scripture. The Mahabharata mentions that killing an embryo is a sin. From this one could infer that though contraceptives are advised abortion is considered as a primal sin. Most Hindus accept that there is a duty to have a family during the householder stage of life, as debt to family lineage called Pitra Rin (Father's Debt) and so are unlikely to avoid having children altogether. The Dharma (doctrine of the religious and moral codes of Hindus) emphasizes the need to act for the sake of the good of the world. Some Hindus, therefore, believe that producing more children than the environment can support goes against this Hindu code. Although fertility is important, conceiving more children than can be supported is treated as violating the Ahimsa (nonviolent rule of conduct).
Because India has such a large and dense population of Hindus, the Dharma still echoes with the ongoing discussion of birth control. This discussion has focused on the environmental issue of overpopulation rather than more personal/religious ethics, and birth control is not a major ethical issue, in modern India.
== Islam ==
The Qur'an does not make any explicit statements about the morality of contraception, but contains statements encouraging procreation. The Islamic prophet Muhammad also is reported to have said "Marry and procreate". In many Muslim-majority countries, birth control (and family planning in general) is readily accessible. Since early Islamic history, Muslim scholars approved of the use of birth control if the two spouses both agreed to it.
Coitus interruptus, a primitive form of birth control, was a known practice at the time of Muhammad, and his companions engaged in it. Muhammad knew about this but never advised or preached against it.
Muslim scholars have extended the example of coitus interruptus, by analogy, to declaring permissible other forms of contraception, subject to three conditions.
As offspring are the right of both the husband and the wife, the birth control method should be used with both parties consent.
The method should not cause permanent sterility.
The method should not otherwise harm the body.
Ahmadiyya Muslims believe birth control is prohibited if resorted to for fear of financial strain.
== Judaism ==
The Jewish view on birth control currently varies between the Orthodox, Conservative, and Reform branches of Judaism. Among Orthodox Judaism, the use of birth control has been considered only acceptable for use in certain circumstances, for example, when the couple already has two children or if they are both in school. However, it is more complex than that. The biblical law of being "fruitful" and "multiplying" is viewed as one that applies only to men, and women have no commandment to have children. This is the reason why women are the ones to choose a form of contraception that they wish to use (i.e. spermicide, oral contraception, intrauterine device, etc.), while males don't. Generally speaking, when Orthodox Jewish couples contemplate the use of contraceptives, they generally consult a rabbi who evaluates the need for the intervention and which method is preferable from a halachic point of view. Including the previously mentioned reasons (already having children, student status, etc.) there are many other reasons for a rabbi to grant a couple permission to use contraception. In many modern Orthodox communities, it is recommended for young newlywed couples to wait a year before having a child so as to strengthen their marital foundation and their relationship before bringing children into the home. This is because children generally require a strong parental unit, and bring challenges and difficult decisions which can be a heavier burden on the marriage itself if the parents are not functioning together well. Since marriage is a sacred relationship of the highest importance in Judaism, couples are always counseled to behave and live in a manner that constantly works to uphold a happy and loving home; this may include planning to slightly delay having children when the couple has had a speedy dating and marriage timeline (as is common in Orthodoxy when many couples abstain from premarital sex).
Conservative Judaism, while generally encouraging its members to follow the traditional Jewish views on birth control has been more willing to allow greater exceptions regarding its use to fit better within modern society. Reform Judaism has generally been the most liberal with regard to birth control allowing individual followers to use their own judgment in what if any, birth control methods they might wish to employ. Jews who follow halakha based on the Talmudic tradition of law will not have sex during the 11–14 days after a woman begins menstruating. This precludes them from utilizing some forms of "natural birth control" such as the "Calendar-based contraceptive methods" which are relatively unobjectionable to other religious groups.
The introduction of oral contraception, or "the pill," in the 1960s and the intrauterine device did not cause a big uprising in the Jewish community as it did in other religious communities due to the understanding of their great benefit and no strict association with their availability and greater promiscuity, as has been the fear in other religions.
== Buddhism ==
Buddhist attitudes to contraception are based on the idea that it is wrong to kill for any reason. The most common Buddhist view on birth control is that contraception is acceptable if it prevents conception, but that contraceptives that work by stopping the development of a fertilized egg are wrong and should not be used.
Buddhists believe that life begins (or more technically: a consciousness arises) when the egg is fertilized.
== Baháʼí Faith ==
The Baháʼí Faith does not "condemn the practice of birth control or...confirm it," although Baháʼís see procreation as an essential part of marriage and oppose contraception which violates the spirit of that provision.
== See also ==
Muslim population growth
Religion and abortion
Abstinence-only sex education
Catholic teachings on sexual morality
Catholic theology of the body
Conscientious objection to abortion
== References ==
== External links ==
Christian Contraception: The Truth about Birth Control—A guide to contraceptives and STDs from an Evangelical Christian Perspective
Epigee: Family Planning in the Jewish Religion
Epigee: Family Planning in Islam
Does the Pro-Life Lobby want to BAN Contraception? = broken link | Wikipedia/Religion_and_birth_control |
The first large-scale human trial of the birth control pill was unethically conducted by Gregory Pincus and John Rock in 1955 in Puerto Rico. Before the drug was approved as safe in the mainland U.S., many poor and uneducated Puerto Rican women were used as guinea pigs by Gregory and John. These trials are a major component in the history of the development of female oral contraceptives, occurring in between initial small trial testing on the east coast and the release of the drug for public consumption. As a result, women gained more independence as they were able to delay pregnancies. The trials are controversial because the Puerto Rican women were uninformed of the potential health and safety risks of the drug. There was a large amount of criticism coming from feminist circles surrounding the trial.
== American testing surrounding the Puerto Rico trials ==
In 1873, the United States federal government passed a series of laws commonly known as the Comstock Laws. The Comstock Laws criminalized the use of the postal service as a means of sending, obtaining, or possessing items considered obscene or salacious (including books, pamphlets, abortifacients, anything used to "facilitate sex", or containing sexual language, etc.). The Comstock Laws thus basically criminalized contraceptive devices and instruments used in abortion procedures. The legislation, however, did not prevent women or businesses from continuing to explore and attempt different methods of birth control. Forced underground, abortion procedures often led to unintentional sterilization or death. Over three-quarters of self-induced abortions resulted in complications.
Infuriated with the lengths that many were forced to go to in order to regulate their own fertility, women began to push for legal rights to contraceptive methods and to govern their own bodies. The movement for public access to birth control started in the early 20th century, propelled by figures like Margaret Sanger. Physicians also lobbied against Comstock Laws, asserting their right to prescribe contraceptives. By the 1930s, U.S. courts were limiting Comstock restrictions on birth control and other purportedly obscene materials.
== Important figures ==
=== Margaret Sanger ===
Margaret Sanger (1879–1966) was a nurse and life-long advocate of women's reproductive rights. Sanger believed that a woman would never truly be free until she had the right to determine whether she wanted to be a mother, and acted on these beliefs by starting a campaign to educate women about sex. She did this while also working as a nurse treating those who had resorted to illegal and unsafe methods of abortion. After fleeing to England for five years, in order to escape persecution for violating the Comstock Laws, Sanger returned to the United States and opened up a clinic (now widely known across the United States as Planned Parenthood) in Brooklyn, New York. The clinic offered women information and resources regarding birth control. The clinic quickly gained popularity and women were soon lining up to be educated. Prior to the birth control movement, there was no uniform sexual education for women, and many found it difficult to find information regarding fertility and contraception. The clinic was only open for ten days before being shut down by authorities for violating the Comstock Act. Sanger was put into jail for 30 days.
Although Sanger's clinic was not a success, the movement for public access to birth control was. By the 1950s there had been a significant amount of research conducted regarding the effects of hormonal drugs. These substances were not explicitly labeled as contraceptive methods, but rather hormonal treatments for infertility, since the laws against contraceptives applied to scientific research as well.
=== John Rock and Gregory Pincus ===
Dr. John Rock and biologist Gregory Pincus, leading experts in fertility and hormone disorders in the United States at the time, collaborated in 1953 to develop an oral contraceptive. Pincus had already established himself as an accomplished scientist after achieving in vitro fertilization in rabbits in 1934, and had established the Worcester Foundation for Experimental Biology in 1944. Around the same time, chemist Carl Djerassi demonstrated the synthesis of progesterone from a wild yam root found in Mexico. The artificial production of progesterone became a key discovery for future fertility research since it was found that high doses of progesterone could halt ovulation.
While Pincus and Rock's research plans had been laid out, they still lacked proper funding. Margaret Sanger and Katharine Dexter McCormick, an heiress who would ultimately fund a large part of the research project, approached Pincus in 1953 about focusing his research on a hormonal contraceptive that would ultimately enable women to control their reproduction.
Once Rock and Pincus had adequate funding, they were able to begin their research. Because Massachusetts law prohibited research on contraceptives, they were forced to conceal the true purpose of their work. The two biologists had proved that their contraceptive hormone treatment had prevented pregnancies in both rats and rabbits, and wanted to take the trial to human test subjects. Consequently, the two made the decision to test their treatment on patients in the Worcester State Psychiatric Hospital. Once the research team was ready to take the trial further in the form of a wider clinical trial, they had to choose a location which would not only offer them a guise from the U.S. government, but also an opportunity to closely monitor and control their test subjects. In the words of Katharine Dexter McCormick, the scientists needed "… a cage of ovulating females to experiment with."
=== Katharine Dexter McCormick ===
Katharine Dexter McCormick was an heiress and philanthropist who ended up funding a large part of the research surrounding the first oral contraceptive pill. She met Gregory Pincus through Margaret Sanger and became interested in the research he was conducting. As Pincus was dealing with a lack of funding from the drug company that supported his research, McCormick stepped in to provide funding. She provided most of the funding for the research and the clinical and field trials that occurred to provide the first oral contraceptive.
=== Edris Rice-Wray ===
Medical researcher Edris Rice-Wray was also heavily involved with the research and raised early concerns about heavy dosage causing health problems for women. The pharmaceutical company G. D. Searle & Company produced the pills for the trial.
== The trials ==
=== Location ===
The research team decided that Puerto Rico would be the most suitable place to test the pill. More specifically, the former municipality of Río Piedras, Puerto Rico, where the first trial would take place in 1956. Puerto Rico offered a promising location for the trials for three key reasons. The first reason was that contraceptives had been legal and socially acceptable in Puerto Rico since 1937, so long as they were being used for medical reasons, rather than "social or economic ones." In fact, researchers from the Social Science Research Center published several research articles in the 1950s concluding that the attitudes toward birth control among working-class Puerto Rican families were extremely positive, despite being majority Catholic. The second reason was that Puerto Rico was facing a tremendous population boom, along with high rates of poverty and unemployment. The birth control pill was offered as a solution to overpopulation, and was seen as a way for the United States government to test population control as a global policy. Likewise, mainland social scientists at the time viewed the high rates of poverty and unemployment as being caused by reproduction, consequently putting the brunt of the blame on Puerto Rican women. Such scientists, like J. Mayone Stycos, believed that Puerto Rican women's "sexual patterns ha[d] become fairly routinized and difficult to change," and thus needed to be heavily regulated. Lastly, the third major reason was that Sanger and Pincus' team had an ally with a strong foothold on the island. Puerto Rico already contained multiple birth control clinics which were originally funded by the U.S. government under the New Deal programs. However, many of these clinics were turned over to the heir of Procter & Gamble and eugenicist Clarence Gamble, who had already been involved in plans led by the government to control the population by pushing women towards sterilization as a method of birth control.
=== Participants ===
When Pincus and Rock began their experiment, over 200 women were registered to take part in the program. The women that were recruited for these trials were " …the poorest of the poor, had no place else to go, and, short of sterilization, no birth control options," and were poorly educated. Prior to the trials, sterilization was the most widespread method of birth limitation in Puerto Rico. Moreover, physicians at the time designated contraceptives as "not practical for the majority of people, [but] only for the more intelligent." Thus, the experiment provided lower income women what they believed was a desirable opportunity to control their fertility while also avoiding sterilization. The women who were given the pills only understood that they would prevent pregnancy and did not know about the potential health and safety risks of taking the pills. As one woman who participated in the trials described it, "[p]hysicians dispatched their assistants to rap on doors throughout the town's slums, telling women they didn't have to have another child if they took the pills regularly. That's how many of the test recruits were found, said Conchita Santos, 80, a lifelong resident…Santos, a homemaker, accepted her first package of pills in 1955, shortly after the birth of her first and only child. 'You have to do what's best for you and your family,' she said. 'It's not easy making a choice like that.'"
The women were also not provided any help or care. Margaret Marsh described in her work how many of these women were exploited for their use. During the trial, these women still had the responsibility of caring for and providing for their families. Marsh describes how one woman was 30 years old with ten children, and a husband that "drank heavily and insisted on daily intercourse, but claimed to be too sick to work." Marsh also described a woman who had five children and a husband who was frequently hospitalized for mental illnesses. At times, this treatment left them unable to work or even care for their family and children.
=== Drug administration and side effects ===
The women were administered 10 milligrams of the experimental combination of estrogen and progesterone, more commonly known as Enovid, the first contraceptive pill. The women participating in the trial began to experience side effects, but their complaints were deemed unreliable and outright dismissed by researchers. Some symptoms reported among patients included dizziness, vomiting, nausea, headache, and menstrual irregularities; some of which were so severe that they required hospitalizations. A small group of female medical students were also recruited to participate in the study, but dropped out due to similar symptoms despite being told that they would receive worse grades if they quit. The researchers believed that these side-effects were insignificant in comparison to what they had discovered; a hormonal oral contraceptive that stopped women from becoming pregnant.
=== Results ===
Despite half of the trial participants dropping out of the experiment and a significant number of pregnancies occurring within the test groups, researchers believed the trials were overall a success. They claimed that the majority of pregnancies occurred when participants either missed pills or withdrew from the study. Thus, they concluded that the pill successfully inhibited ovulation using two steroids: 19-nor-17-ethinyl testosterone and 17-ethinyl estaeneolone. John Rock further proclaimed that the drug could "provide a natural means of fertility control such as nature uses after ovulation and during pregnancy." Enovid was finally approved by the FDA in 1960 as an oral contraceptive.
After the trials in Puerto Rico, the drug was approved in the U.S. in 1957 for consumer use as a medication to treat severe menstrual side effects. The drug was approved as a female oral contraceptive, the first in the U.S., in May 1960. G.D. Searle and company profited greatly from widespread sales of the product, although the company was initially extremely hesitant to be associated with the trials in any way.
=== Deaths ===
Three deaths occurred among patients who were taking the birth control drug during the trials. Despite strong circumstantial evidence that the pill was causing these unexpected deaths, they were not reported for two reasons. Firstly, those conducting the trial considered the deaths to be coincidental. Secondly, autopsies were never conducted on the bodies of the three women.
== Enovid ==
The drug used in this trial was known as Enovid. The drug was a combination of estrogen and progesterone, the same hormones used in modern combined oral contraceptive pills. Enovid was submitted for regulatory approval in 1957.
=== Dosage ===
The drug Enovid used in this trial was a much higher dosage than oral contraceptive pills prescribed today. Modern health practices facilitate prescriptions for birth control, averaging about 0.75 milligrams per dose. The original dosing of 10 milligrams is more than 100 times the acceptable concentration of hormones in contraceptive pills today. The original dosage from the trials was eventually dropped to 5 milligrams after severe side effects were observed, including nausea, dizziness, headaches, and blood clots, along with the death of three women in Puerto Rico.
=== Timeline of Enovid ===
Enovid was submitted first for regulatory approval in 1957 for the treatment of menstrual disorders and infertility. Originally, it was not submitted to the FDA as an oral contraceptive, although it was developed as such. A supplemental application was submitted to the FDA in 1959 to expand its usage as a contraceptive. It was approved in 1960 and in 1961 and it was found that it could cause rare, but serious complications.
== Ethics and controversy ==
Even though the composition of the original birth control pill was modified after trials due to the dangerous levels of hormones, the discovery and the authorization of the pill made a profound impact on women's reproductive rights in the United States. Women were now able to directly control their own fertility because of the legalization of the pill and the studies that aided in the authorization of the pill. Instead of having to deal with an accidental pregnancy, women were provided with the opportunity to delay having children, allowing them to pursue higher educational goals or seek employment. Based on statistics, the pill was considered "…one of the most transformational developments in the business sector in the last 85 years. Fully one-third of the wage gains women have made since the 1960s are the result of access to oral contraceptives." Additionally, studies have shown evidence that "between 1969 and 1980, the dropout rate among women with access to the pill was 35 percent lower than women without access to the pill," and that "birth control has been estimated to account for more than 30 percent of the increase in the proportion of women in skilled careers from 1970 to 1990."
The ethics of the trial in Puerto Rico are still debated. A Puerto Rican woman named Delia Mestre, who participated in the trial unknowingly, was questioned about her participation in the experiments. She explained that "the experiments were both good and bad. Why didn't anyone let us make some decisions for ourselves?" She also stated, "I have difficulty explaining that time to my own grown children. I have very mixed feelings about the entire thing." Mestre and the other women who participated in the trials were not allowed to make an informed decision on whether they wanted to serve in the trials.
== Feminist response to trials ==
In a 2006 review of Ana María García's 1982 film La Operación, Tamara Falicov noted that "Puerto Rico became an important testing ground for U.S. pharmaceutical companies working on the effectiveness of the birth control pill."
== References == | Wikipedia/Contraceptive_trials_in_Puerto_Rico |
Lactic acid/citric acid/potassium bitartrate, sold under the brand name Phexxi, is a non-hormonal combination medication used as a method of birth control. It contains lactic acid, citric acid, and potassium bitartrate. It is a gel inserted into the vagina.
The most common adverse reactions include vulvovaginal burning sensation, vulvovaginal pruritus, vulvovaginal mycotic infection, urinary tract infection, vulvovaginal discomfort, bacterial vaginosis, vaginal discharge, genital discomfort, dysuria, and vulvovaginal pain.
== Medical uses ==
The combination is indicated for the prevention of pregnancy in females of reproductive potential for use as an on-demand method of contraception.
== History ==
The combination was approved for medical use in the United States in May 2020.
== References == | Wikipedia/Lactic_acid/citric_acid/potassium_bitartrate |
Fertility awareness (FA) refers to a set of practices used to determine the fertile and infertile phases of a woman's menstrual cycle. Fertility awareness methods may be used to avoid pregnancy, to achieve pregnancy, or as a way to monitor gynecological health.
Methods of identifying infertile days have been known since antiquity, but scientific knowledge gained during the past century has increased the number, variety, and especially accuracy of methods.
Systems of fertility awareness rely on observation of changes in one or more of the primary fertility signs (basal body temperature, cervical mucus, and cervical position), tracking menstrual cycle length and identifying the fertile window based on this information, or both. Other signs may also be observed: these include breast tenderness and mittelschmerz (ovulation pains), urine analysis strips known as ovulation predictor kits (OPKs), and microscopic examination of saliva or cervical fluid. Also available are computerized fertility monitors.
== Terminology ==
Symptoms-based methods involve tracking one or more of the three primary fertility signs: basal body temperature, cervical mucus, and cervical position. Systems relying exclusively on cervical mucus include the Billings Ovulation Method, the Creighton Model, and the Two-Day Method. Symptothermal methods combine observations of basal body temperature (BBT), cervical mucus, and sometimes cervical position. Calendar-based methods rely on tracking a woman's cycle and identifying her fertile window based on the lengths of her cycles. The best known of these methods is the Standard Days Method. The Calendar-Rhythm method is also considered a calendar-based method, though it is not well defined and has many different meanings to different people.
Systems of fertility awareness may be referred to as fertility awareness–based methods; the term Fertility Awareness Method (FAM) refers specifically to the system taught by Toni Weschler. The term natural family planning is sometimes used to refer to any use of fertility awareness methods, the lactational amenorrhea method and periodic abstinence during fertile times. A method of fertility awareness may be used by natural family planning users to identify these fertile times.
Women who are breastfeeding a child and wish to avoid pregnancy may be able to practice the lactational amenorrhea method. The lactational amenorrhea method is distinct from fertility awareness, but because it also does not involve contraceptives, it is often presented alongside fertility awareness as a method of "natural" birth control.
Within the Catholic Church and some Protestant denominations, the term natural family planning is often used to refer to Fertility Awareness pointing out it is the only method of family planning approved by the Church.
== History ==
=== Development of calendar-based methods ===
It is not known exactly when it was first discovered that women have predictable periods of fertility and infertility. It is already clearly stated in the Talmud tractate Niddah, that a woman only becomes pregnant in specific periods in the month, which seemingly refers to ovulation. St. Augustine wrote about periodic abstinence to avoid pregnancy in the year 388 (the Manichaeans attempted to use this method to remain childfree, and Augustine condemned their use of periodic abstinence). One book states that periodic abstinence was recommended "by a few secular thinkers since the mid-nineteenth century," but the dominant force in the twentieth century popularization of fertility awareness-based methods was the Roman Catholic Church.
In 1905 Theodoor Hendrik van de Velde, a Dutch gynecologist showed that women only ovulate once per menstrual cycle. In the 1920s, Kyusaku Ogino, a Japanese gynecologist, and Hermann Knaus, from Austria, independently discovered that ovulation occurs about fourteen days before the next menstrual period. Ogino used his discovery to develop a formula for use in aiding infertile women to time intercourse to achieve pregnancy. In 1930, John Smulders, a Roman Catholic physician from the Netherlands, used this discovery to create a method for avoiding pregnancy. Smulders published his work with the Dutch Roman Catholic medical association, and this was the first formalized system for periodic abstinence: the rhythm method.
=== Introduction of temperature and cervical mucus signs ===
In the 1930s, Reverend Wilhelm Hillebrand, a Catholic priest in Germany, developed a system for avoiding pregnancy based on basal body temperature. This temperature method was found to be more effective at helping women avoid pregnancy than were calendar-based methods. Over the next few decades, both systems became widely used among Catholic women. Two speeches delivered by Pope Pius XII in 1951 gave the highest form of recognition to the Catholic Church's approval—for couples who needed to avoid pregnancy—of these systems. In the early 1950s, John Billings discovered the relationship between cervical mucus and fertility while working for the Melbourne Catholic Family Welfare Bureau. Billings and several other physicians, including his wife, Dr. Evelyn Billings, studied this sign for a number of years, and by the late 1960s had performed clinical trials and begun to set up teaching centers around the world.
=== First symptoms-based teaching organizations ===
While Dr. Billings initially taught both the temperature and mucus signs, they encountered problems in teaching the temperature sign to largely illiterate populations in developing countries. In the 1970s they modified the method to rely on only mucus. The international organization founded by Dr. Billings is now known as the World Organization Ovulation Method Billings.
The first organization to teach a symptothermal method was founded in 1971. John and Sheila Kippley, lay Catholics, joined with Dr. Konald Prem in teaching an observational method that relied on all three signs: temperature, mucus, and cervical position. Their organization is now called Couple to Couple League International. The next decade saw the founding of other now-large Catholic organizations, Family of the Americas (1977), teaching the Billings method, and the Pope Paul VI Institute (1985), teaching a new mucus-only system called the Creighton Model.
Up until the 1980s, information about fertility awareness was only available from Catholic sources. The first secular teaching organization was the Fertility Awareness Center in New York, founded in 1981. Toni Weschler started teaching in 1982 and published the bestselling book Taking Charge of Your Fertility in 1995. Justisse was founded in 1987 in Edmonton, Canada. These secular organizations all teach symptothermal methods. Although the Catholic organizations are significantly larger than the secular fertility awareness movement, independent secular teachers have become increasingly common since the 1990s.
=== Ongoing development ===
Development of fertility awareness methods is ongoing. In the late 1990s, the Institute for Reproductive Health at Georgetown University introduced two new methods. The TwoDay Method, a mucus-only system, and CycleBeads and iCycleBeads (the digital version), based on the Standard Days Method, are designed to be both effective and simple to teach, learn, and use. In 2019, Urrutia et al. released a study as well as interactive graph over-viewing all studied fertility awareness based methods. Femtech companies such as Dot and Natural Cycles have also produced new studies and apps to help women avoid pregnancy. Natural Cycles is the first app of its kind to receive FDA approval.
== Fertility signs ==
Most menstrual cycles have several days at the beginning that are infertile (pre-ovulatory infertility), a period of fertility, and then several days just before the next menstruation that are infertile (post-ovulatory infertility). The first day of red bleeding is considered day one of the menstrual cycle. Different systems of fertility awareness calculate the fertile period in slightly different ways, using primary fertility signs, cycle history, or both.
== Primary fertility signs ==
The three primary signs of fertility are basal body temperature (BBT), cervical mucus, and cervical position. A woman practicing symptoms-based fertility awareness may choose to observe one sign, two signs, or all three. Many women experience secondary fertility signs that correlate with certain phases of the menstrual cycle, such as abdominal pain and heaviness, back pain, breast tenderness, and mittelschmerz (ovulation pains).
=== Basal body temperature ===
This usually refers to a temperature reading collected when a person first wakes up in the morning (or after their longest sleep period of the day). The true BBT can only be obtained by continuous temperature monitoring through internally worn temperature sensors. In women, ovulation will trigger a rise in BBT between 0.2º and 0.5 °C. (0.5 and 1.°F) that lasts approximately until the next menstruation. This temperature shift may be used to determine the onset of post-ovulatory infertility. (See ref. 30)
=== Cervical mucus ===
The appearance of cervical mucus and vulvar sensation are generally described together as two ways of observing the same sign. Cervical mucus is produced by the cervix, which connects the uterus to the vaginal canal. Fertile cervical mucus promotes sperm life by decreasing the acidity of the vagina, and also it helps guide sperm through the cervix and into the uterus. The production of fertile cervical mucus is caused by estrogen, the same hormone that prepares a woman's body for ovulation. By observing her cervical mucus and paying attention to the sensation as it passes the vulva, a woman can detect when her body is gearing up for ovulation, and also when ovulation has passed. When ovulation occurs, estrogen production drops slightly and progesterone starts to rise. The rise in progesterone causes a distinct change in the quantity and quality of mucus observed at the vulva.
=== Cervical position ===
The cervix changes position in response to the same hormones that cause cervical mucus to be produced and to dry up. When a woman is in an infertile phase of her cycle, the cervix will be low in the vaginal canal; it will feel firm to the touch (like the tip of a person's nose); and the os—the opening in the cervix—will be relatively small, or "closed". As a woman becomes more fertile, the cervix will rise higher in the vaginal canal, it will become softer to the touch (more like a person's lips), and the os will become more open. After ovulation has occurred, the cervix will revert to its infertile position.
== Cycle history ==
Calendar-based systems determine both pre-ovulatory and post-ovulatory infertility based on cycle history. When used to avoid pregnancy, these systems have higher perfect-use failure rates than symptoms-based systems but are still comparable with barrier methods, such as diaphragms and cervical caps.
Mucus- and temperature-based methods used to determine post-ovulatory infertility, when used to avoid conception, result in very low perfect-use pregnancy rates. However, mucus and temperature systems have certain limitations in determining pre-ovulatory infertility. A temperature record alone provides no guide to fertility or infertility before ovulation occurs. Determination of pre-ovulatory infertility may be done by observing the absence of fertile cervical mucus; however, this results in a higher failure rate than that seen in the period of post-ovulatory infertility. Relying only on mucus observation also means that unprotected sexual intercourse is not allowed during menstruation, since any mucus would be obscured.
The use of certain calendar rules to determine the length of the pre-ovulatory infertile phase allows unprotected intercourse during the first few days of the menstrual cycle while maintaining a very low risk of pregnancy. With mucus-only methods, there is a possibility of incorrectly identifying mid-cycle or anovulatory bleeding as menstruation. Keeping a basal body temperature chart enables accurate identification of menstruation, when pre-ovulatory calendar rules may be reliably applied. In temperature-only systems, a calendar rule may be relied on alone to determine pre-ovulatory infertility. In symptothermal systems, the calendar rule is cross-checked by mucus records: observation of fertile cervical mucus overrides any calendar-determined infertility.
Calendar rules may set a standard number of days, specifying that (depending on a woman's past cycle lengths) the first three to six days of each menstrual cycle are considered infertile. Or, a calendar rule may require calculation, for example holding that the length of the pre-ovulatory infertile phase is equal to the length of a woman's shortest cycle minus 21 days. Rather than being tied to cycle length, a calendar rule may be determined from the cycle day on which a woman observes a thermal shift. One system has the length of the pre-ovulatory infertile phase equal to a woman's earliest historical day of temperature rise minus seven days.
== Other techniques ==
Ovulation predictor kits can detect imminent ovulation from the concentration of luteinizing hormone (LH) in a woman's urine. A positive ovulation predictor kit result is usually followed by ovulation within 12–36 hours.
Saliva microscopes, when correctly used, can detect ferning structures in the saliva that precede ovulation. Ferning is usually detected beginning three days before ovulation, and continuing until ovulation has occurred. During this window, ferning structures occur in cervical mucus as well as saliva.
Computerized fertility monitors, such as Lady-Comp, are available under various brand names. These monitors may use BBT-only systems, they may analyze urine test strips, they may use symptothermal observations, they may monitor the electrical resistance of saliva and vaginal fluids, or a combination of any of these factors.
A symptohormonal method of fertility awareness method developed at Marquette University uses the ClearBlue Easy fertility monitor to determine the fertile window. The monitor measures estrogen and LH to determine the peak day. This method is also applicable during postpartum, breastfeeding, and perimenopause, and requires less abstinence than other fertility awareness method methods. Some couples prefer this method because the monitor reading is objective and is not affected by sleep quality as basal body temperature can be.
== Benefits and drawbacks ==
Fertility awareness has a number of unique characteristics:
Fertility awareness can be used to monitor reproductive health. Changes in the cycle can alert the user to emerging gynecological problems. Fertility awareness can also be used to aid in diagnosing known gynecological problems such as infertility.
Fertility awareness may be used to avoid pregnancy or to aid in conception.
Use of fertility awareness can give insight to the workings of women's bodies, and may allow women to take greater control of their own fertility.
Some symptoms-based forms of fertility awareness require observation or touching of cervical mucus, an activity with which some women are not comfortable. Some practitioners prefer to use the term "cervical fluid" to refer to cervical mucus, in an attempt to make the subject more acceptable to these women.
Some drugs, such as decongestants, can change cervical mucus. In women taking these drugs, the mucus sign may not accurately indicate fertility.
Some symptoms-based methods require tracking of basal body temperatures. Because irregular sleep can interfere with the accuracy of basal body temperatures, shift workers and those with very young children, for example, might not be able to use those methods.
FA requires action daily—detailed record keeping. Some may find the time and detail requirements too complicated.
== As birth control ==
By restricting unprotected sexual intercourse to the infertile portion of the menstrual cycle, a woman and her partner can prevent pregnancy. During the fertile portion of the menstrual cycle, the couple may use barrier contraception or abstain from sexual intercourse.
=== Advantages ===
There are no drug-related side effects to fertility awareness.
FA can be free or have a very low up-front cost. Users may employ a coach, use computer software, or buy a chart, calendar, or basal thermometer. The direct costs are low when compared to other methods.
FA can be used with barrier contraception so that intercourse may continue through the fertile period. Unlike barrier use without FA, practicing FA can allow couples to use barrier contraception only when necessary.
FA can be used to immediately switch from pregnancy avoidance to pregnancy planning if the couple decides it is time to plan for conception.
=== Disadvantages ===
Use of a barrier or other backup method is required on fertile days; otherwise the couple must abstain. To reduce pregnancy risk to below 1% per year, there are an average of 13 days where abstinence or backup must be used during each cycle. For women with very irregular cycles—such as those common during breastfeeding, perimenopause, or with hormonal diseases such as PCOS—abstinence or the use of barriers may be required for months at a time.
Typical use effectiveness is lower than most other methods.
Fertility awareness does not protect against sexually transmitted disease.
=== Effectiveness ===
The effectiveness of fertility awareness, as of most forms of contraception, can be assessed two ways. Perfect use or method effectiveness rates only include people who follow all observational rules, correctly identify the fertile phase, and refrain from unprotected intercourse on days identified as fertile. Actual use or typical use effectiveness rates include all women relying on fertility awareness to avoid pregnancy, including those who fail to meet the "perfect use" criteria. Rates are generally presented for the first year of use. Most commonly, the Pearl Index is used to calculate effectiveness rates, but some studies use decrement tables.
The failure rate of fertility awareness varies widely depending on the system used to identify fertile days, the instructional method, and the population being studied. Some studies have found actual failure rates of 25% per year or higher. At least one study has found a failure rate of less than 1% per year with continuous intensive coaching and monthly review, and several studies have found actual failure rates of 2%–3% per year.
When used correctly and consistently (i.e., with perfect use) with ongoing coaching, under study conditions some studies have found some forms of FA to be 99% effective.
From Contraceptive Technology:
Post-ovulation methods (i.e., abstaining from intercourse from menstruation until after ovulation) have a method failure rate of 1% per year.
The symptothermal method has a method failure rate of 2% per year.
Cervical mucus–only methods have a method failure rate of 3% per year.
Calendar rhythm has a method failure rate of 9% per year.
The Standard Days Method has a method failure rate of 5% per year.
=== Reasons for lower typical-use effectiveness ===
Several factors account for typical-use effectiveness being lower than perfect-use effectiveness:
conscious user non-compliance with instructions (having unprotected intercourse on a day identified as fertile)
mistakes on the part of those providing instructions on how to use the method (instructor providing incorrect or incomplete information on the rule system)
mistakes on the part of the user (misunderstanding of rules, mistakes in charting)
The most common reason for the lower actual effectiveness is not mistakes on the part of instructors or users, but conscious user non-compliance—that is, the couple knowing that the woman is likely to be fertile at the time but engaging in sexual intercourse nonetheless. This is similar to failures of barrier methods, which are primarily caused by non-use of the method.
== To achieve pregnancy ==
=== Intercourse timing ===
Timing intercourse with a person's estimated 'fertile window' is a practice sometimes called 'timed intercourse'. The effectiveness of timed intercourse is not entirely clear, however, timed intercourse using urine tests that predict ovulation may help improve the rate of pregnancy and live births for some couples trying to conceive such as those who have been trying for less than 12-months and who are under 40 years old. It is not clear from medical evidence if timed intercourse improves the rate of ultra-sound confirmed pregnancies and it is also not clear if timed intercourse has an effect on a person's level of stress or their quality of life. Pregnancy rates for sexual intercourse are also affected by several other factors. Regarding frequency, there are recommendations of sexual intercourse every 1 or 2 days, or every 2 or 3 days. Studies have shown no significant difference between different sex positions and pregnancy rate, as long as it results in ejaculation into the vagina. Social science research has found that timing intercourse can become a gendered 'chore' in heterosexual married couples trying to conceive, with women tracking their ovulation cycles and dictating to their husbands when they should have sexual intercourse.
=== Problem diagnosis ===
Regular menstrual cycles are sometimes taken as evidence that a woman is ovulating normally, and irregular cycles as evidence she is not. However, many women with irregular cycles do ovulate normally, and some with regular cycles are actually anovulatory or have a luteal phase defect. Records of basal body temperatures, especially, but also of cervical mucus and position, can be used to accurately determine if a woman is ovulating, and if the length of the post-ovulatory (luteal) phase of her menstrual cycle is sufficient to sustain a pregnancy.
Fertile cervical mucus is important in creating an environment that allows sperm to pass through the cervix and into the fallopian tubes where they wait for ovulation. Fertility charts can help diagnose hostile cervical mucus, a common cause of infertility. If this condition is diagnosed, some sources suggest taking guaifenesin in the few days before ovulation to thin out the mucus.
=== Pregnancy testing and gestational age ===
Pregnancy tests are not accurate until 1–2 weeks after ovulation. Knowing an estimated date of ovulation can prevent a woman from getting false negative results due to testing too early. Also, 18 consecutive days of elevated temperatures means a woman is almost certainly pregnant. Estimated ovulation dates from fertility charts are a more accurate method of estimating gestational age than the traditional pregnancy wheel or last menstrual period (LMP) method of tracking menstrual periods. Because of high rates of very early miscarriage (25% of pregnancies are lost within the first six weeks since the woman's last menstrual period), the methods used to detect pregnancy may lead to bias in conception rates. Less-sensitive methods will detect lower conception rates, because they miss the conceptions that resulted in early pregnancy loss.
== See also ==
Billings ovulation method
Creighton Model FertilityCare System
Fertility monitor
Lactational amenorrhea method
Kindara
TwoDay Method
== References ==
== Further reading ==
Toni Weschler (2006). Taking Charge of Your Fertility (10th Anniversary ed.). New York: Collins. ISBN 0-06-088190-9.
John F. Kippley; Sheila K. Kippley (1996). The Art of Natural Family Planning (Fourth ed.). Cincinnati, OH: Couple to Couple League International. ISBN 0-926412-13-2. | Wikipedia/Fertility_awareness_method |
Forced marriage is a marriage in which one or more of the parties is married without their consent or against their will. A marriage can also become a forced marriage even if both parties enter with full consent if one or both are later forced to stay in the marriage against their will.
A forced marriage differs from an arranged marriage, in which both parties presumably consent to the assistance of their parents or a third party such as a matchmaker in finding and choosing a spouse. There is often a continuum of coercion used to compel a marriage, ranging from outright physical violence to subtle psychological pressure.
Though now widely condemned by international opinion, forced marriages still take place in various cultures across the world, particularly in parts of South Asia and Africa. Some scholars object to use of the term "forced marriage" because it invokes the consensual legitimating language of marriage (such as husband/wife) for an experience that is precisely the opposite. A variety of alternative terms have been proposed, including Forced conjugal association and Conjugal slavery.
The United Nations views forced marriage as a form of human rights abuse, since it violates the principle of the freedom and autonomy of individuals. The Universal Declaration of Human Rights states that a person's right to choose a spouse and enter freely into marriage is central to their life and dignity, and their equality as a human being. The Roman Catholic Church deems forced marriage grounds for granting an annulment—for a marriage to be valid both parties must give their consent freely. The Supplementary Convention on the Abolition of Slavery also prohibits marriage without right to refusal by both parties and requires a minimum age for marriage to prevent this. Similarly, the International Labour Organization recognizes forced marriage as a form of modern slavery.
In 2009, the Special Court for Sierra Leone's (SCSL) Appeals Chamber found the abduction and confinement of women for "forced marriage" in war to be a new crime against humanity (AFRC decision). The SCSL Trial Chamber in the Charles Taylor decision found that the term 'forced marriage' should be avoided and rather described the practice in war as 'conjugal slavery' (2012).
In 2013, the first United Nations Human Rights Council resolution against child, early, and forced marriages was adopted; the resolution recognizes child, early, and forced marriage as involving violations of human rights which "prevents individuals from living their lives free from all forms of violence and that has adverse consequences on the enjoyment of human rights, such as the right to education, [and] the right to the highest attainable standard of health including sexual and reproductive health", and also states that "the elimination of child, early and forced marriage should be considered in the discussion of the post-2015 development agenda." The elimination of this harmful practice is one of the targets of the United Nations Sustainable Development Goal 5.
== Historical context ==
Arranged marriages were very common throughout the world until the 18th century. Typically, marriages were arranged by parents, grandparents or other relatives. The actual practices varied by culture, but usually involved the legal transfer of dependency of the woman from her father to the groom. The movement towards the emancipation of women in the 19th and 20th centuries led to major changes to marriage laws, especially regarding property and economic status. By the mid-20th century, many Western countries had enacted legislation establishing legal equality between spouses in family law. The period of 1975–1979 saw a major overhaul of family laws in countries such as Italy,
Spain, Austria, West Germany, and Portugal. In 1978, the Council of Europe passed the Resolution (78) 37 on equality of spouses in civil law. Among the last European countries to establish full gender equality in marriage were Switzerland, Greece, Spain, the Netherlands, and France and the paternal authority of a man over his family was ended in 1970, it was only in 1985 that a legal reform abolished the stipulation that the husband had the sole power to administer the children's property.
Certain family members had different forms of forced marriages in the early 1800s and in countries such as the U.S., UK, and even Western Germany (albeit not all of Germany). Marriage to a woman without the father's consent was still uneasy at the time. In 1953, the forced marriage specialist John Lester Senior, who was working at his home in Los Angeles California at the time, arranged the meaning of forced marriage during the 1953 Forced Marriage Reunion in Western Los Angeles, which lasted from 1953 to 1955.
An arranged marriage is not the same as a forced marriage: in the former, the spouse can reject the offer; in the latter, they do not. The line between arranged and forced marriage is however often difficult to draw, due to the implied familial and social pressure to accept the marriage and obey one's parents in all respects. The rejection of an offer to marry was sometimes seen as a humiliation of the prospective groom and his family.
In Europe, during the late 18th century and early 19th century, the literary and intellectual movement of romanticism presented new and progressive ideas about love marriage, which started to gain acceptance in society. In the 19th century, marriage practices varied across Europe, but in general, arranged marriages were more common among the upper class. Arranged marriages were the norm in Russia before early 20th century, most of which were endogamous. Child marriages were common historically, but began to be questioned in the 19th and 20th centuries. Child marriages are often considered to be forced marriages, because children (especially young ones) are not able to make a fully informed choice whether or not to marry, and are often influenced by their families.
In Western countries, during the past decades, the nature of marriage—especially with regard to the importance of marital procreation and the ease of divorce—has changed dramatically, which has led to less social and familial pressure to get married, providing more freedom of choice concerning choosing a spouse.
Historically, forced marriage was also used to require a captive (slave or prisoner of war) to integrate with the host community, and accept his or her fate. One example is the English blacksmith John R. Jewitt, who spent three years as a captive of the Nootka people on the Pacific Northwest Coast in 1802–1805. He was ordered to marry, because the council of chiefs thought that a wife and family would reconcile him to staying with his captors for life. Jewitt was given a choice between forced marriage for himself and capital punishment for both him and his "father" (a fellow captive). "Reduced to this sad extremity, with death on the one side, and matrimony on the other, I thought proper to choose what appeared to me the least of the two evils" (p154).
Forced marriage was also practiced by authoritarian governments as a way to meet population targets. The Khmer Rouge regime in Cambodia systematically forced people into marriages, to increase the population and continue the revolution.These marriage ceremonies consisted of no fewer than three couples and could be as large as 160 couples. Generally, the village chief or a senior leader of the community would approach both parties and inform them that they were to be married and the time and place the marriage would occur. Often, the marriage ceremony would be the first time the future spouses would meet. Parents and other family members were not allowed to participate in selecting the spouse or to attend the marriage ceremony. The Khmer Rouge maintained that parental authority was unnecessary because it "w[as] to be everyone's 'mother and father.'"
Raptio is a Latin term referring to the large scale abduction of women, (kidnapping) either for marriage or enslavement (particularly sexual slavery). The practice is surmised to have been common since anthropological antiquity.
In the 21st century, forced marriages have come to attention in European countries, within the context of immigration from cultures in which they are common. The Istanbul Convention prohibits forced marriages (see Article 37).
=== Timeline of laws against forced marriages ===
1215: Magna Carta banned forced marriage of widows in England.
1724: Peter the Great signed decree banning forced marriages in Russia.
1734: Sweden banned forced marriages.
1804: Napoleonic Code banned forced marriage.
1889: New law in Japan required consent of both spouses for marriage, although the consent of women was still likely to be forced until the early 20th century, as women gradually gained access to education and financial independence.
1901: Zimbabwe banned forced marriages, but practice continued covertly.
1917: Ottoman family law banned forced marriage.
1926: Criminal code of Uzbekistan criminalized forced marriages.
1928: Albania: The Civil Code of 1928 bans forced marriages and gives married women the right to divorce and equal inheritance.
1928: Criminal code of Kazakhstan criminalized forced marriages.
1946: North Korea banned forced marriages and selling of women.
1950: China banned forced marriages via New Marriage Law
1956: Tunisia banned forced marriages.
1959: Iraq banned forced marriages.
1960: Vietnam banned forced marriage.
1962: Mali banned forced marriage.
1965: Ivory Coast banned forced marriages.
1973: England and Wales: The Matrimonial Causes Act 1973 stipulates that a forced marriage is voidable.
1978: New communist government banned forced marriages in Afghanistan.
1991: Laos banned forced marriages.
1994: Kyrgyzystan banned bride kidnapping with up to three years in prison.
1998: Sweden made forced marriages a criminal offense.
1990: Burkina Faso banned forced marriages, however the law is not well enforced and the practice is widespread.
1999: Ghana banned forced marriages.
2003: Norway made forced marriage a criminal offense.
2004:
Benin banned forced marriages.
Morocco banned forced marriages.
Georgia banned bride kidnapping.
Ethiopia banned forced and child marriage with up to 20 years in prison.
2005:
Saudi Arabia banned forced marriages.
Germany made it a criminal offense to force someone to marry.
2006:
Austria criminalized forced marriage.
Democratic Republic of the Congo outlawed forced marriage.
2007:
Pakistan introduced a law to ban forced marriages with up to three years in jail.
Sierra Leone banned forced marriages.
Belgium made forced marriage a criminal offense.
Togo banned forced marriage.
2008:
Denmark criminalized forced marriage.
Luxembourg criminalized forced marriage.
2009: Afghanistan made forced marriage a criminal offense.
2010: France introduced forced marriage as an aggravating circumstance of other crimes.
2011:
Scotland made forced marriage a criminal offense.
Australian court ruled against validility of a foreign marriage made under duress.
Zambia banned forced marriages.
2013:
Australian government made it a criminal offense to force someone to marry.
Switzerland criminalized forced marriages increasing penalty to up to five years in prison.
Hungary criminalized forced marriage.
France criminalized forcing someone to marry abroad.
Kyrgyzystan increased punishment for bride kidnapping up to 10 years in prison.
2014:
UK government made it criminal offense to force someone to marry in England, Wales and Scotland.
Malta criminalized forced marriage.
2015:
Canada made forced marriage a criminal offense punishable up to five years in prison.
Georgia criminalized forced marriages with up to 400 hours of public labour or up to two years in jail.
2016:
Gambia banned forced marriages.
Cameroon criminalized forced marriages.
New Zealand criminalized forced marriages.
2018: Morocco made forced marriages a criminal offense.
2022: Indonesia banned forces marriages with up to nine years in prison.
== Conventions ==
=== Supplementary Convention on the Abolition of Slavery ===
The 1956 Supplementary Convention on the Abolition of Slavery, the Slave Trade, and Institutions and Practices Similar to Slavery defines "institutions and practices similar to slavery" to include:
c) Any institution or practice whereby:
(i) A woman, without the right to refuse, is promised or given in marriage on payment of a consideration in money or in kind to her parents, guardian, family or any other person or group; or
(ii) The husband of a woman, his family, or his clan, has the right to transfer her to another person for value received or otherwise; or
(iii) A woman on the death of her husband is liable to be inherited by another person;
=== Istanbul Convention ===
The Council of Europe Convention on preventing and combating violence against women and domestic violence, also known as the Istanbul Convention, states:
Article 32 – Civil consequences of forced marriages
Parties shall take the necessary legislative or other measures to ensure that marriages concluded under force may be voidable, annulled or dissolved without undue financial or administrative burden placed on the victim.
Article 37 – Forced marriage
Parties shall take the necessary legislative or other measures to ensure that the intentional conduct of forcing an adult or a child to enter into a marriage is criminalised.
Parties shall take the necessary legislative or other measures to ensure that the intentional conduct of luring an adult or a child to the territory of a Party or State other than the one she or he resides in with the purpose of forcing this adult or child to enter into a marriage is criminalised.
== Types ==
There are numerous factors which can lead to a culture which accepts and encourages forced marriages. Reasons for performing forced marriages include: strengthening extended family links; controlling unwanted behavior and sexuality; preventing 'unsuitable' relationships; protecting and abiding by cultural values; keeping the wealth in the extended family; dealing with the consequences of pregnancy out of wedlock; considering the contracting of a marriage as the duty of the parents; obtaining a guarantee against poverty; aiding immigration.
=== Relation to dowry and bride price ===
The traditional customs of dowry and bride price contribute to the practice of forced marriage. A dowry is the property or money that a wife (or wife's family) brings to her husband upon marriage. A bride price is an amount of money or property or wealth paid by the groom (or his family) to the parents of the bride upon marriage.
=== Marriage by abduction ===
Marriage by abduction, also known as bride kidnapping, is a practice in which a man abducts the woman he wishes to marry. Marriage by abduction has been practiced throughout history around the world and continues to occur in some countries today, particularly in Central Asia, the Caucasus and parts of Africa. A girl or a woman is kidnapped by the groom-to-be, who is often helped by his friends. The victim is often raped by the groom-to-be, for her to lose her virginity, so that the man is able to negotiate a bride price with the village elders to legitimize the marriage. The future bride then has no choice in most circumstances, but to accept: if the bride goes back to her family, she (and her family) will often be ostracized by the community because the community thinks she has lost her virginity, and she is now 'impure'. A different form of marital kidnapping, groom kidnapping, occurs in some areas where payment of a dowry is generally expected.
=== As debt negotiation ===
Money marriage refers to a marriage where a girl, usually, is married off to a man to settle debts owed by her parents.
=== As dispute resolution ===
A forced marriage is also often the result of a dispute between families, where the dispute is 'resolved' by giving a female from one family to the other. Vani is a cultural custom found in parts of Pakistan wherein a young girl is forcibly married as part of the punishment for a crime committed by her male relatives. Vani is a form of forced child marriage, and the result of punishment decided by a council of tribal elders named jirga.
=== Widow inheritance ===
Widow inheritance, also known as bride inheritance, is a cultural and social practice whereby a widow is required to marry a kinsman of her late husband, often his brother. It is prevalent in certain parts of Africa. The practice of wife inheritance has also been blamed for the spread of HIV/AIDS.
=== As war spoils ===
"In conflict areas, women and girls are sometimes forced to marry men on either side of the conflict. This practice has taken place recently in countries such as Syria, Sierra Leone, Uganda, and the Democratic Republic of the Congo. Historically, this was common throughout the world, with women from the communities of the war enemy being considered "spoils of war", who could be kidnapped, raped and forced into marriage or sexual slavery". Because women were regarded as property, it seemed reasonable to see them as the chattel of the war enemy, which could now be appropriated and used by the winner.
=== Shotgun wedding ===
A shotgun wedding is a form of forced marriage occasioned by an unplanned pregnancy. Some religions and cultures consider it a moral imperative to marry in such a situation, based on reasoning that premarital sex or out-of-wedlock births are sinful, not sanctioned by law, or otherwise stigmatized. Giving birth outside marriage can, in some cultures, trigger extreme reactions from the family or community, including honor killings.
The term "shotgun wedding" is an American colloquialism, though it is also used in other parts of the world. It is based on a hyperbolic scenario in which the pregnant (or sometimes only "deflowered") woman's father resorts to coercion (such as threatening with a shotgun) to ensure that the male partner who caused the pregnancy goes through with it, sometimes even following the man to the altar to prevent his escape. The use of violent coercion to marry was never legal in the United States, although many anecdotal stories and folk songs record instances of such intimidation in the 18th and 19th centuries. Purposes of the wedding include recourse from the man for the act of impregnation and to ensure that the child is raised by both parents as well as to ensure that the woman has material means of support. In some cases, a major objective was the restoring of social honor to the mother.
Shotgun weddings have become less common as the stigma associated with out-of-wedlock births has gradually faded and the number of such births has increased; the increasing availability of birth control, sex education, and abortion, as well as material support to unwed mothers, such as Elterngeld, child benefits, parental leave, and free kindergartens, have reduced the perceived need for such measures.
== Consequences ==
=== For victims and society ===
Early and forced marriages can contribute to girls being placed in a cycle of poverty and powerlessness. Most are likely to experience mistreatment such as violence, abuse and forced sexual relations. This means that women who marry younger in age are more likely to be dominated by their husbands. They also experience poor sexual and reproductive health. Young married girls are more likely to contract HIV and their health could be in jeopardy. Most people who are forced into a marriage lack education and are often illiterate. Young ones tend to drop out of school shortly before they get married.
Forced marriage often means a lifetime of rape, abuse and domestic servitude, and the loss of reproductive rights, financial rights and basic human rights. For women and girls, forced marriage often means forced motherhood.
=== Escaping a forced marriage ===
Ending a forced marriage may be extremely difficult in many parts of the world. For instance, in parts of Africa, one of the main obstacles for leaving the marriage is the bride price. Once the bride price has been paid, the girl is seen as belonging to the husband and his family. If she wants to leave, the husband may demand back the bride price that he had paid to the girl's family. The girl's family often cannot or does not want to pay it back. Some countries also have Male Guardianship requirements, prohibiting women from paying themselves out, but in other countries it has happened multiple times.
British citizens escaping forced marriage abroad are forced to pay their repatriation costs or get into debt. This makes escaping a forced marriage harder.
In the United States, Unchained At Last is the only nonprofit organization operating to help people in the U.S. escape forced or arranged marriages by providing free legal and social services.
=== Honor killing ===
Forced marriages are often related to violence, both in regard to violence perpetrated inside the marriage (domestic violence), and in regard to violence inflicted in order to force an unwilling participant to accept the marriage, or to punish a refusal (in extreme cases women and girls who do not accept the marriage are subjected to honor killings).
=== Legislative consequences ===
Depending by jurisdiction, a forced marriage may or may not be void or voidable. Victims may be able to seek redress through annulment or divorce. In England and Wales, the Matrimonial Causes Act 1973 stipulates that a forced marriage is voidable. In some jurisdictions, people who had coerced the victim into marriage may face criminal charges.
== Sharia law ==
In Islamic law, consent is needed for a valid marriage. Islamic marriage is concluded (but not excluding the bride) between the guardian (wali) of the bride and bridegroom, not between bridegroom and bride. However, the bride’s permission is still necessary and her wali, guardian, merely represents her.
The guardian (wali) of the bride can only be a free Muslim. The wali has the power to initiate a marriage contract on behalf of a child before puberty, but once the child attains puberty he or she can accept or reject the marriage. The marriage contract can be annulled on grounds of coercion.
However, in the Hanafi school of jurisprudence, a guardian is not needed to make the marriage valid.
== By country ==
=== Africa ===
==== Madagascar ====
Forced marriage is prevalent in Madagascar. Girls are married off by their families, and often led to believe that if they refuse the marriage they will be "cursed". In some cases, the husband is much older than his bride, and when she becomes a widow, she is discriminated and excluded by society.
==== Malawi ====
According to Human Rights Watch, Malawi has "widespread child and forced marriage" and half of the girls marry before 18. The practice of bride price, known also as lobolo, is common in Malawi, and plays a major role in forced marriage. Wife inheritance is also practiced in Malawi. After marriage, wives have very limited rights and freedoms; and general preparation of young girls for marriage consists in describing their role as that of being subordinated to the husband.
==== Mauritania ====
Forced marriage in Mauritania takes three principal forms: forced marriage to a cousin (known as maslaha); forced marriage to a rich man for the purpose of financial gain; and forced polygamous marriage to an influential man.
==== Morocco ====
In 2018, a law went into effect known as the Hakkaoui law because Bassima Hakkaoui drafted it; among other things, it includes a ban on forced marriage.
==== Niger ====
Forced marriage is common in Niger. Niger has the highest prevalence of child marriage in the world; and also the highest total fertility rate. Girls who attempt to leave forced marriages are most often rejected by their families and are often forced to enter prostitution in order to survive. Due to the food crisis, girls are being sold into marriage.
Balkissa Chaibou is known as one of the most famous activists against forced marriage in Niger. Chaibou was 12 when she was informed by her own mother that she was to be married to her cousin, and when she was 16, she took to the courts. With little success, Chaibou was forced to a women's shelter before she was finally able to go home where she learned of her parents changed views on forced marriage, that they were now against it.
==== Somalia ====
The "Sexual Intercourse Related Crimes Bill" proposed in August 2020 in Somalia would allow both child marriage and forced marriage. The new bill "risks legitimizing child marriage, among other alarming practices," U.N. human rights chief Michelle Bachelet said. Thousands of people in Somalia circulated a petition against the bill, including representatives of the Mogadishu-based Elman Peace and Human Rights Center. More than 45% of young women in Somalia marry or are "in union" before the age of 18.
==== South Africa ====
In South Africa, ukuthwala is the practice of abducting young girls and forcing them into marriage, often with the consent of their parents. The practice occurs mainly in rural parts of South Africa, in particular the Eastern Cape and KwaZulu-Natal. The girls who are involved in this practice are frequently under-aged, including some as young as eight. The practice received negative publicity, with media reporting in 2009 that more than 20 Eastern Cape girls are forced to drop out of school every month because of ukuthwala.
==== Tanzania ====
In Tanzania, the practices of forced marriage and child marriage impacts the human rights and childhood of girls. Families sell their girls to older men for financial benefits, causing pain among young girls. Oftentimes, girls are married off as soon as they hit puberty, which can be as young as seven years old. To the older men, these young brides act as symbols of masculinity and accomplishment. Child brides endure rape, causing health risks and growth impediments. Primary education is usually not completed for young girls in forced marriages. Married and pregnant students are often discriminated against, and expelled and excluded from school. The Law of Marriage Act currently does not address issues with guardianship and child marriage. The issue of child marriage establishes a minimum age of 18 for the boys of Tanzania, but no such minimum age is established for girls.
==== The Gambia ====
In 2016, during a feast ending the Muslim holy month of Ramadan, the Gambian President Yahya Jammeh announced that child and forced marriages were banned.
=== Asia ===
==== Compensation marriage ====
Compensation marriage, known variously as vani, swara and sang chatti, is the traditional practice of forced marriage of women and young girls to resolve tribal feuds in parts of Pakistan and Afghanistan. The practice is illegal in Pakistan, though it continues to be widely practiced in Pakistan's Khyber-Pakhtunkhwa province. In Afghanistan, the practice is known as baad.
==== Afghanistan ====
Forced marriage is very common in Afghanistan, and sometimes women resort to suicide to escape these marriages. A report by Human Rights Watch found that about 95% of girls and 50% of adult women imprisoned in Afghanistan were in jail on charges of the "moral crimes" of "running away" from home or zina. Obtaining a divorce without the consent of the husband is nearly impossible in Afghanistan, and women attempting a de facto separation risk being imprisoned for "running away". While it is not socially acceptable for women and girls to leave home without permission, "running away" is not defined as a criminal offense in the Afghan Penal Code. However, in 2010 and 2011, the Afghan Supreme Court issued instructions to courts to charge women with "running away" as a crime. This makes it nearly impossible for women to escape forced marriages. The Human Rights Watch report stated that:
According to the UN, as of 2008, 70 to 80 percent of marriages in Afghanistan were forced, taking place without full and free consent or under duress. Another study found that 59 percent of women had experienced forced marriage.
==== Pakistan ====
DIG Sindh Police Aftab Pathan had said on the occasion of a consultative workshop organized by FIA Sindh that in 2014, 1,261 cases of abduction of women for forced marriage were registered. Five accused were jailed while the case of 369 accused was pending. There were also 45 cases of abduction of children under the age of ten. There are reports of forced conversion of girls belonging to minorities in Pakistan and then forced marriages to a Muslim man. Forced marriages are the norm in Pakistan.
However, Federal Shariat court had taken strict actions against forced marriages and pressurized provincial governments, after which Balochistan government drafted a bill "The Balochistan Child Marriages Prohibition Act, 2021".
==== China ====
Forced marriages have been documented between Chinese men and women from neighboring countries. These women, usually through false promises of work, are lured to China and forced to marry.
==== Indonesia ====
Some Indonesian tribes have traditions or local customs that may be considered a forced marriage. For instance, Sasak people who still adhere to old customs believe that if their daughter were going out with a man until late at night, then marriage must be carried out soon after. People in Sumba also practices bride kidnapping.
However, in April 2022, Indonesian legislature passed Law No. 12 of 2022 on Sexual Violence Crimes. The law considers forced marriage a form of sexual violence and outlaw it, with offenders can be sentenced to a maximum imprisonment of 9 years and/or face a maximum fine of Rp200 million. Included as forms of forced marriage are child marriage, forcing rape victims to marry the rapists, and forcing people to marry in the name of local customs.
==== Iran ====
Forced marriage remains common for Kurdish girls in Iran and is also one of the major reasons for self-immolation in Iran. In 1998, UNICEF reported high rates of forced marriage in Iranian Kurdistan, including at an early age, but also reported that the practice was declining. Kurdish cultural norms which facilitate the practice of forced and child marriage perpetuate the fear of violence amongst Kurdish girls in Iran.
==== Nepal ====
Girls in Nepal are often seen as an economic burden to the family, due to dowry. Parents often compel young girls to marry, because older and more educated men can demand a higher dowry. In 2009, the Nepalese government decided to offer a cash incentive (50,000 Nepali rupees – $641) to men for marrying widowed women. Because widows often lose social status in Nepalese society, this policy was meant to 'solve' their problems. However, many widows and human rights groups protested these regulations, denouncing them as humiliating and as encouraging coerced marriages.
==== Sri Lanka ====
During the Sri Lankan Civil War, a 2004 report in the journal Reproductive Health Matters found that forced marriage in Sri Lanka was taking place in the context of the armed conflict, where parents forced teenage girls into marriage in order to ensure that they do not lose their chastity (considered an increased risk due to the conflict) before marriage, which would compromise their chances of finding a husband.
==== Tajikistan ====
=== Europe ===
==== Germany ====
In 2011, the family ministry of Germany found that 3,000 people were in forced marriages, nearly all from migrant families and most (83.4%) from Muslim families, by querying help bureaus. These figures exceeded the estimates of help organisation Terre des Femmes, which up until then had estimated that about 1,000 migrant women sought help annually. More than half of the women had experienced physical abuse, and 27% were threatened with weapons or received death threats. Of the victims, 30% were 17 years old or younger. 31.8% were from Germany, 26.4% from Asia, 22.2% from Turkey, and 5.6% from Africa. In 2016, the German ministry of the interior found that 1,475 children were in forced marriages including more than 1,110 girls. Of those particularly affected 664 were Syrians, 157 were Afghans, and 100 were Iraqis.
==== United Kingdom ====
Forced marriages can be made because of family pride, the wishes of the parents, or social obligation. For example, according to Ruqaiyyah Waris Maqsood, many forced marriages in Britain within the British Pakistani community are aimed at providing British citizenship to a member of the family currently in Pakistan to whom the instigator of the forced marriage feels a sense of duty. In response to the problem of forced marriages among immigrants in the UK, the Forced Marriage (Civil Protection) Act 2007 (applicable in England and Wales, and in Northern Ireland) was passed, which enables the victims of forced marriage to apply for court orders for their protection. Similar legislation was passed in Scotland: the Forced Marriage, etc. (Protection and Jurisdiction) (Scotland), Act 2011 gives courts the power to issue protection orders.
In 2008, it was estimated that about 3,000 forced marriages took place each year.
In June 2012, the British Government, under Prime Minister David Cameron, declared that forced marriage would become a criminal offence in the United Kingdom. In November 2013, it was reported that a case was brought before the High Court in Birmingham by local authority officials, involving a then-14-year-old girl who was taken to Pakistan, forced to marry a man ten years her senior, and, two weeks later, forced to consummate the marriage with threats, resulting in pregnancy; the court case ended with Mr. Justice Holman saying he was powerless to make a "declaration of non-recognition" of the forced marriage, since he was prevented by law from granting a declaration that her marriage was "at its inception, void". Mr. Justice Holman said that the girl, now 17, would have to initiate proceedings herself to have the marriage nullified. British courts can also issue civil orders to prevent forced marriage, and since 2014, refusing to obey such an order is grounds for a prison sentence of up to five years.
The Anti-Social Behaviour, Crime and Policing Act 2014 makes forcing someone to marry (including abroad) a criminal offence. The law came into effect in June 2014 in England and Wales, and in October 2014 in Scotland. In Northern Ireland, the Human Trafficking and Exploitation (Criminal Justice and Support for Victims) Act (Northern Ireland) 2015 criminalises forced marriage (section 16 – Offence of forced marriage).
In July 2014, the United Kingdom hosted its first global Girl Summit; the goal of the Summit was to increase efforts to end child marriage, early, and forced marriage, and female genital mutilation within a generation.
The first conviction for forced marriage in the United Kingdom occurred in June 2015, with the convicted being a man from Cardiff, who was subsequently sentenced to 16 years in prison.
Of the cases recorded by the government's Force Marriage Unit, run jointly between the Foreign and Commonwealth Office and the Home Office, the majority involved South Asia communities, with 37% linked to Pakistan, 11% linked to Bangladesh, and 7% linked to India. About 30% involved victims below the age of 18.
==== Sweden ====
In July 2014, forced marriages were criminalised to protect individuals who were forced to marry against their will (Swedish: äktenskapstvång). The maximum sentence is four years. No court has given the maximum sentence as of January 2019.
Schools in Skåne in the southern part of Sweden report that they discover that about 25 youth are forced to marry annually due to them being part of a shame society. An investigation by government organisation Ungdomsstyrelsen reported that 70,000 youth perceived they were unfree in their choice of spouse.
In July 2016, an Afghan man in Sweden was sentenced to 4 years in prison for forcing his daughter to marry someone in Afghanistan in the first Swedish conviction. He was also convicted for assault, threats, robbery, blackmailing, false imprisonment, and sexually molesting his daughter's Swedish boyfriend.
In January 2019, the maternal uncle and aunt of a 16-year-old girl of an Iraqi family were sentenced to 21 months in jail and had to pay €12500 in damages for forced marriage. In December 2016, her family discovered that the girl was dating a boy, and the family decided to marry her off to a cousin without her knowledge. Under the false pretense that her grandmother was mortally ill, the girl, her mother, aunt, and uncle travelled to Iraq where all but the girl had return tickets. In Iraq, the grandmother proved to be in good health, and the girl was to marry her cousin. Despite having no contacts in Iraq, and having her mobile phone taken from her, she managed to return to Sweden eight months later.
==== Other ====
Although forced marriage in Europe is predominately found within the immigrant population, it is also present among some local populations, especially among the Roma communities in Eastern Europe.
The British Forced marriage consultation, published in 2011, found forcing someone to marry to be a distinct criminal offence in Austria, Belgium, Turkey, Denmark, Norway, and Germany. In 2014, it became a distinct criminal offence in England and Wales.
The Council of Europe Convention on preventing and combating violence against women and domestic violence defines and criminalizes forced marriage, as well as other forms of violence against women. The Convention came into force on 1 August 2014.
In November 2014, UCL held an event, Forced Marriage: The Real Disgrace, where the award-winning documentary Honor Diaries was shown, and a panel, including Jasvinder Sanghera CBE (Founder of Karma Nirvana), Seema Malhotra MP (Labour Shadow Minister for Women), and Dr Reefat Drabu (former Assistant General Secretary of the Muslim Council of Britain), discussed the concept of izzat (honour), recent changes in British law, barriers to tackling forced marriage, and reasons to be hopeful of positive change.
=== The Americas ===
==== Canada ====
Forced marriage may be practised among some immigrant communities in Canada. Until recently, forced marriage has not received very much attention in Canada. The lack of attention has protected the practice from legal intervention. In 2015, Parliament enacted two new criminal offences to address the issue. Forcing a person to marry against their will is now a criminal offence under the Criminal Code, as is assisting or aiding a child marriage, where one of the participants is under age 16. There has also been the long-standing offence of solemnizing an illegal marriage, which was also modified by the 2015 legislation.
In addition to these criminal offences, the Civil Marriage Act stipulates: "Marriage requires the free and enlightened consent of two persons to be the spouse of each other", as well as setting 16 as the minimum age for marriage.
==== United States ====
According to Nancie L Katz, thousands of Pakistani girls have been flown out of the New York City area to Pakistan to undergo forced marriages; those who resist are threatened and coerced. The AHA Foundation commissioned a study by the John Jay College of Criminal Justice to research the incidence of forced marriage in New York City. The results of the study were equivocal. However, AHA Foundation for the past 11 years has operated a helpline that successfully referred numerous individuals seeking help in fleeing or avoiding a forced marriage to qualified service providers and law enforcement. According to the National Center for Victims of Crime Conference, there are "limited laws/policies directly addressing forced marriage", although more general non-specific laws may be used. The organization Unchained at Last, an organization in the United States, assists women escaping forced or arranged marriages with free legal services and other resources. It was founded by Fraidy Reiss.
The Fundamentalist Church of Jesus Christ of Latter-Day Saints (FLDS) has been suspected of trafficking underage girls across state lines, as well as across the US–Canada and US–Mexico borders, for the purpose of sometimes involuntary plural marriage and sexual abuse. The FLDS is suspected by the Royal Canadian Mounted Police of having trafficked more than 30 under-age girls from Canada to the United States between the late 1990s and 2006 to be entered into polygamous marriages. RCMP spokesman Dan Moskaluk said of the FLDS's activities: "In essence, it's human trafficking in connection with illicit sexual activity." According to the Vancouver Sun, it is unclear whether or not Canada's anti-human trafficking statute can be effectively applied against the FLDS's pre-2005 activities, because the statute may not be able to be applied retroactively. An earlier three-year-long investigation by local authorities in British Columbia into allegations of sexual abuse, human trafficking, and forced marriages by the FLDS resulted in no charges, but did result in legislative change.
=== Oceania ===
==== Australia ====
In 2013, forced marriage laws were established in Australia; they have a maximum penalty of imprisonment for seven years.
In 2024, Sakina Muhammad Jan, a Hazara woman from Shepparton, became the first person to be jailed under Australia's forced marriage laws after ordering her 21-year-old daughter Ruqia Hadari to marry a man who later murdered her.
==== New Zealand ====
== Forced divorce ==
One internationally publicized and criticized instance of forced divorce occurred in Saudi Arabia in July 2005. Justice Ibrahim Al-Farraj of the first-instance court in Al-Jouf Province annulled in absentia the nearly three-year-old marriage of Mansour al-Timani and Fatima `Azzaz in response to a complaint from `Azzaz's half-brothers that her husband's tribe had insufficient social status compared to hers; the brothers also said that al-Timani had misrepresented his background. Her half-brothers filed the lawsuit with power of attorney obtained from Fatima's father, who was her male legal guardian while she was unmarried (and who later died). Al-Timani was not served the divorce papers until nine months later, in February, 2006.
`Azzaz gave birth to their son in detention during the couple's forced separation. `Azzaz spent three months living with her mother and the couple's two children before sneaking off to Jeddah with Al-Timani, where they were arrested for living together as an unmarried couple. `Azzaz was detained in Dammam Public Prison with both their children and then another Dammam facility described as an orphanage with her son because she refused to return to her mother's family under her half-brothers' guardianship. She feared being married off to a "more suitable" man, As he was afraid they would be mistreated if sent to live with the brothers' family, Al-Timani later gained custody of their daughter, but was repeatedly detained and warned not to talk to the media. He said the first instance court had not asked the couple for its side of the story, that sharia law did not use tribal affiliation as a requirement for marriage, and that the brothers brought the case as part of an inheritance dispute. The Riyadh Court of Appeals (known as a Court of Cassation) upheld the annulment in January, 2007. Authorities stopped letting the couple see each other after she gave an interview to Arab News in November, 2006.
After King Salman asked the Supreme Court of Saudi Arabia, which did not exist at the time of the initial decision, to review the case, lawyers submitted arguments about al-Timani's tribal background. The Supreme Court ruled in January 2010 against the annulment, allowing the couple to reunite.
== Statistics ==
Child marriage (2008–2014):
Summary:
== See also ==
Activists and women famous for refusing forced marriage
Nojoud Ali
Franca Viola
== References ==
== Further reading ==
Books
Haenan, Iris (2014). Force & Marriage: The criminalisation of forced marriage in Dutch, English and international criminal law. Intersentia. doi:10.1017/9781780685298. ISBN 9781780685298. - Published online in November 2017.
Gill, Aisha K.; Anitha, Sundari (2011). Forced Marriage: Introducing a Social Justice and Human Rights Perspective. New York: Zed Books. ISBN 978-1-84813-464-5.
Melanie, Milburne (2008). The Fiorenza Forced Marriage. Toronto: Harlequin.
Journal articles
Esthappan S; Bastomski S1; Zweig J; Dank M; Love H (19 October 2018). "Understanding Forced Marriage in the United States: Developing Measures, Examining its Nature, and Assessing Gender Disparities". J Interpers Violence. 36 (11–12): 5730–5760. doi:10.1177/0886260518801935. PMID 30340441. S2CID 53011008.{{cite journal}}: CS1 maint: numeric names: authors list (link)
Chantler K (July 2012). "Recognition of and intervention in forced marriage as a form of violence and abuse". Trauma Violence Abuse. 13 (3): 176–183. doi:10.1177/1524838012448121. PMID 22643068. S2CID 24031180. Epub May 29, 2012.
Gangoli, Geetanjali; Amina Razak; Melanie McCarry (June 2006). "Forced Marriage and Domestic Violence among South Asian Communities in North East England" (PDF). School for Policy Studies, University of Bristol and Northern Rock Foundation. Archived from the original (PDF) on 10 August 2017. Retrieved 3 December 2019.
Articles
European Immigrants Continue to be Forced Into Marriage World Politics Watch 31 January 2007
Forced Marriage, Another Perspective
Interview with Serap Cileli World Politics Watch 1 February 2007
Forced Marriage Among Europe's Immigrants: Hülya Kalkan's Story World Politics Watch 8 February 2007
Freedom Charity, UK charity raising awareness of forced marriage and 'dis-honour' based violence.
BBC News story: Forced marriage 'could be banned'
Akhtar Amin (13 November 2006). "Swara practised with impunity in tribal areas". Daily Times. Archived from the original on 25 October 2012. Retrieved 5 June 2008.
Declan Walsh (5 June 2008). "15 child brides used to settle Pakistan feud". The Guardian. London. Retrieved 5 June 2008.
Ashfaq Yusufzai (1 April 2006). "Blood Feuds Trap Girls in 'Compensation Marriages'". Inter Press Service. Archived from the original on 11 June 2008. Retrieved 5 June 2008.
"Swara—A Bridge over troubled waters". Ethnomedia. Archived from the original on 4 December 2008. Retrieved 5 June 2008.
"Virtual Slavery: The Practice of "Compensation Marriages"". United Nations Population Fund. Archived from the original on 14 February 2012. Retrieved 5 June 2008. (Microsoft Word document)
Captured Hearts: An epidemic of bride kidnappings may at last be waning in Kyrgyzstan- National Geographic, Paul Salopek
== External links ==
U.S. Citizenship and Immigration Services: Forced Marriage | Wikipedia/Forced_marriage |
Coitus interruptus, also known as withdrawal, pulling out or the pull-out method, is an act of birth control during sexual intercourse, whereby the penis is withdrawn from a vagina prior to ejaculation so that the ejaculate (semen) may be directed away in an effort to avoid insemination.
This method was used by an estimated 38 million couples worldwide in 1991. Coitus interruptus does not protect against sexually transmitted infections (STIs).
== History ==
Perhaps the oldest description of the use of the withdrawal method to avoid pregnancy is the story of Onan in the Torah and the Bible. This text is believed to have been written over 2,500 years ago. Societies in the ancient civilizations of Greece and Rome preferred small families and are known to have practiced a variety of birth control methods.: 12, 16–17 There are references that have led historians to believe withdrawal was sometimes used as birth control. However, these societies viewed birth control as a woman's responsibility, and the only well-documented contraception methods were female-controlled devices (both possibly effective, such as pessaries, and ineffective, such as amulets).: 17, 23
After the decline of the Roman Empire in the 5th century AD, contraceptive practices fell out of use in Europe; the use of contraceptive pessaries, for example, is not documented again until the 15th century. If withdrawal was used during the Roman Empire, knowledge of the art may have been lost during its decline.: 33, 42
From the 18th century until the development of modern methods, withdrawal was one of the most popular methods of birth-control practised globally.
== Effects ==
Like many methods of birth control, reliable effect is achieved only by correct and consistent use. Observed failure rates of withdrawal vary depending on the population being studied: American studies have found actual failure rates of 15–28% per year. One US study, based on self-reported data from the 2006–2010 cycle of the National Survey of Family Growth, found significant differences in failure rate based on parity status. Women with 0 previous births had a 12-month failure rate of only 8.4%, which then increased to 20.4% for those with 1 prior birth and again to 27.7% for those with 2 or more.
An analysis of Demographic and Health Surveys in 43 developing countries between 1990 and 2013 found a median 12-month failure rate across subregions of 13.4%, with a range of 7.8–17.1%. Individual countries within the subregions were even more varied. A large scale study of women in England and Scotland during 1968–1974 to determine the efficacy of various contraceptive methods found a failure rate of 6.7 per 100 woman-years of use. This was a “typical use” failure rate, including user failure to use the method correctly. In comparison, the combined oral contraceptive pill has an actual use failure rate of 2–8%, while intrauterine devices (IUDs) have an actual use failure rate of 0.1–0.8%. Condoms have an actual use failure rate of 10–18%. However, some authors suggest that actual effectiveness of withdrawal could be similar to the effectiveness of condoms; this area needs further research. (See Comparison of birth control methods.)
For couples that use coitus interruptus consistently and correctly at every act of intercourse, the failure rate is 4% per year. This rate is derived from an educated guess based on a modest chance of sperm in the pre-ejaculate. In comparison, the pill has a perfect-use failure rate of 0.3%, IUDs a rate of 0.1–0.6%, and internal condoms a rate of 2%.
It has been suggested that the pre-ejaculate ("Cowper's fluid") emitted by the penis prior to ejaculation may contain spermatozoa (sperm cells), which would compromise the effectiveness of the method. However, several small studies have failed to find any viable sperm in the fluid. While no large conclusive studies have been done, it is believed by some that the cause of method (correct-use) failure is the pre-ejaculate fluid picking up sperm from a previous ejaculation. For this reason, it is recommended that the male partner urinate between ejaculations, to clear the urethra of sperm, and wash any ejaculate from objects that might come near the woman's vulva (such as hands and penis).
However, recent research suggests that this might not be accurate. A contrary, yet non-generalizable study that found mixed evidence, including individual cases of a high sperm concentration, was published in March 2011. A noted limitation to these previous studies' findings is that pre-ejaculate samples were analyzed after the critical two-minute point. That is, looking for motile sperm in small amounts of pre-ejaculate via microscope after two minutes – when the sample has most likely dried – makes examination and evaluation "extremely difficult". Thus, in March 2011 a team of researchers assembled 27 male volunteers and analyzed their pre-ejaculate samples within two minutes after producing them. The researchers found that 11 of the 27 men (41%) produced pre-ejaculatory samples that contained sperm, and 10 of these samples (37%) contained a "fair amount" of motile sperm (in other words, as few as 1 million to as many as 35 million). This study therefore recommends, in order to minimize unintended pregnancy and disease transmission, the use of condoms from the first moment of genital contact. As a point of reference, a study showed that, of couples who conceived within a year of trying, only 2.5% included a male partner with a total sperm count (per ejaculate) of 23 million sperm or less. However, across a wide range of observed values, total sperm count (as with other identified semen and sperm characteristics) has weak power to predict which couples are at risk of pregnancy. Regardless, this study introduced the concept that some men may consistently have sperm in their pre-ejaculate, due to a "leakage," while others may not.
Similarly, another robust study performed in 2016 found motile sperm in the pre-ejaculate of 16.7% (7/42) healthy men. What more, this study attempted to exclude contamination of sperm from ejaculate by drying the pre-ejaculate specimens to reveal a fern-like pattern, characteristics of true pre-ejaculate. All pre-ejaculate specimens were examined within an hour of production and then dried; all pre-ejaculate specimens were found to be true pre-ejaculate. It is widely believed that urinating after an ejaculation will flush the urethra of remaining sperm. However, some of the subjects in the March 2011 study who produced sperm in their pre-ejaculate did urinate (sometimes more than once) before producing their sample. Therefore, some males can release the pre-ejaculate fluid containing sperm without a previous ejaculation.
== Advantages ==
The advantage of coitus interruptus is that it can be used by people who have objections to, or do not have access to, other forms of contraception. Some people prefer it so they can avoid possible adverse effects of hormonal contraceptives or so that they can have a full experience and be able to "feel" their partner. Other reasons for the popularity of this method are its anecdotal increase in male sexual deftness, it has no direct monetary cost, requires no artificial devices, has no physical side effects, can be practiced without a prescription or medical consultation, and provides no barriers to stimulation.
== Disadvantages ==
Compared to the other common reversible methods of contraception such as IUDs, hormonal contraceptives, and male condoms, coitus interruptus is less effective at preventing pregnancy. As a result, it is also less cost-effective than many more effective methods: although the method itself has no direct cost, users have a greater chance of incurring the risks and expenses of either child-birth or abortion. Only models that assume all couples practice perfect use of the method find cost savings associated with the choice of withdrawal as a birth control method.
The method is largely ineffective in the prevention of sexually transmitted infections (STIs), like HIV, since pre-ejaculate may carry viral particles or bacteria which may infect the partner if this fluid comes in contact with mucous membranes. However, a reduction in the volume of bodily fluids exchanged during intercourse may reduce the likelihood of disease transmission compared to using no method due to the smaller number of pathogens present.
== Prevalence ==
Based on data from surveys conducted during the late 1990s, 3% of women of childbearing age worldwide rely on withdrawal as their primary method of contraception. Regional popularity of the method varies widely, from a low of 1% in Africa to 16% in Western Asia.
In the United States, according to the National Survey of Family Growth (NSFG) in 2014, 8.1% of reproductive-aged women reported using withdrawal as a primary contraceptive method. This was a significant increase from 2012 when 4.8% of women reported the use of withdrawal as their most effective method. However, when withdrawal is used in addition to or in rotation with another contraceptive method, the percentage of women using withdrawal jumps from 5% for sole use and 11% for any withdrawal use in 2002, and for adolescents from 7.1% of sole withdrawal use to 14.6% of any withdrawal use in 2006–2008.
When asked if withdrawal was used at least once in the past month by women, use of withdrawal increased from 13% as sole use to 33% ever use in the past month. These increases are even more pronounced for adolescents 15 to 19 years old and young women 20 to 24 years old Similarly, the NSFG reports that 9.8% of unmarried men who have had sexual intercourse in the last three months in 2002 used withdrawal, which then increased to 14.5% in 2006–2010, and then to 18.8% in 2011–2015. The use of withdrawal varied by the unmarried man's age and cohabiting status, but not by ethnicity or race. The use of withdrawal decreased significantly with increasing age groups, ranging from 26.2% among men aged 15–19 to 12% among men aged 35–44. The use of withdrawal was significantly higher for never-married men (23.0%) compared with formerly married (16.3%) and cohabiting (13.0%) men.
For 1998, about 18% of married men in Turkey reported using withdrawal as a contraceptive method.
== See also ==
Coitus reservatus
Coitus saxonicus
Masturbation
== References ==
== External links ==
Contraception and abortion in Islam
Withdrawal | Wikipedia/Withdrawal_method |
Lactational amenorrhea, also called postpartum infertility, is the temporary postnatal infertility that occurs when a woman is amenorrheic (not menstruating) and fully breastfeeding.
== Physiology ==
=== Hormonal pathways and neuroendocrine control ===
Breastfeeding delays the resumption of normal ovarian cycles by disrupting the pattern of pulsatile release of gonadotropin-releasing hormone (GnRH) from the hypothalamus and hence luteinizing hormone (LH) from the pituitary. The plasma concentrations of follicle-stimulating hormone (FSH) during lactation are sufficient to induce follicle growth, but the inadequate pulsatile LH signal results in a reduced estradiol production by these follicles. When follicle growth and estradiol secretion does increase to normal, lactation prevents the generation of a normal preovulatory LH surge and follicles either fail to rupture, or become atretic or cystic. Only when lactation declines sufficiently to allow generation of a normal preovulatory LH surge to occur will ovulation take place with the formation of a corpus luteum of variable normality. Thus lactation delays the resumption of normal ovarian cyclicity by disrupting but not totally inhibiting, the normal pattern of release of GnRH by the hypothalamus. The mechanism of disruption of GnRH release remains unknown.
In women, hyperprolactinemia is often associated with amenorrhea, a condition that resembles the physiological situation during lactation (lactational amenorrhea). Mechanical detection of suckling increases prolactin levels in the body to increase milk synthesis. Excess prolactin may inhibit the menstrual cycle directly, by a suppressive effect on the ovary, or indirectly, by decreasing the release of GnRH.
=== Suckling stimulus ===
Suckling intensity directly correlates with the duration of the amenorrheal period following birth. Suckling intensity has several dynamic components: frequency of suckling, duration of the suckling bout, and duration of suckling in a 24 hour period. It is not clear which of these plays the most critical role in maintaining amenorrhea. Suckling intensity is highly variable across populations. Studies of U.S. and Scottish women show that at least six bouts per day and 60 minutes of suckling in a 24-hour period will typically sustain amenorrhea. Concurrent studies of !Kung women in Botswana and Gainj women in Papua New Guinea have shown that very frequent, very short suckling bouts of about 3 minutes, 40 to 50 times per day correlate with typical amenorrhea of up to two years postpartum.
When an infant suckles, sensory receptors in the nipple send a signal to the anterior pituitary gland in the brain, which secretes prolactin and oxytocin. Prolactin and oxytocin trigger the release (letdown) of milk and its ejection from the nipple in a positive feedback loop. It was previously thought that prolactin hormone, which is released by the anterior pituitary in response to the direct nerve stimulation of suckling, was responsible for creating the hormonal pathways necessary to sustain amenorrhea. Now, however, it seems that this relationship is one of correlation not causation as prolactin levels in the blood plasma are simply an indicator of suckling frequency. Suckling, and the subsequent release of prolactin, is not directly responsible for postpartum infecundity. Rather it is one mechanism that increases milk production, thereby increasing the metabolic cost of breastfeeding to mothers, which contributes to sustained infecundity.
Suckling as proxy indicator of infecundity rather than a direct, hormonal causal factor is supported in studies contrasting the nursing intensity hypothesis, which says that more intense (prolonged, frequent) breastfeeding will result in a longer period of lactational amenorrhea, and the metabolic load model, which posits that maternal energy availability will be the main factor determining postpartum amenorrhea and the timing of the return of ovarian function.
=== Lactation and energy availability ===
Postpartum ovarian function and the return of fecundity depend heavily on maternal energy availability. This is due to the relatively consistent metabolic costs of milk production across populations, which fluctuate slightly but represent a significant cost to the mother. The metabolic load hypothesis states that women with more available energy or caloric/metabolic resources will likely resume ovarian function sooner, because breastfeeding represents a proportionally lower burden on their overall metabolic function. Women with less available energy experience a proportionally higher burden due to breastfeeding and therefore have less surplus metabolic energy to invest in continued reproduction. The metabolic load model is therefore consistent with the nursing intensity hypothesis, in that more intense nursing increases the relative metabolic burden of breastfeeding on the mother. It also takes into account the overall energy supply of the mother in determining whether she has enough caloric/metabolic resources available to her to make reproduction possible. If net energy supply is high enough, a woman will resume ovarian cycling sooner despite still breastfeeding the current infant.
=== Infecundity ===
Amenorrhea itself is not necessarily an indicator of infecundity, as the return of ovarian cycling is a gradual process and full fecundity may occur before or after first postpartum menses. Additionally, spotting or the appearance of first postpartum menses can be a result of either lochia or estrogen withdrawal and not actual ovulation. Lactational amenorrhea has evolved as a mechanism for preserving the health of the mother. This period of infecundity allows the mother to focus her energy on breastfeeding as well as allow time for her body to heal between births. The frequency and durations of the feedings determine how long the mother will continue to be infecund during breastfeeding. However there is variation across different cultures. The Turkana, Gainj, and Quechua societies all breastfeed on demand until their child is around 2 years old. The timing of returned ovulation for these women is however varied. Because of this, interbirth intervals vary across these three societies.
== Return of fertility ==
Return of menstruation following childbirth varies widely among individuals. This return does not necessarily mean a woman has begun to ovulate again. The first postpartum ovulatory cycle might occur before the first menses following childbirth or during subsequent cycles. A strong relationship has been observed between the amount of suckling and the contraceptive effect, such that the combination of feeding on demand rather than on a schedule and feeding only breast milk rather than supplementing the diet with other foods will greatly extend the period of effective contraception. In fact, it was found that among the Hutterites, more frequent bouts of nursing, in addition to maintenance of feeding in the night hours, led to longer lactational amenorrhea. An additional study that references this phenomenon cross-culturally was completed in the United Arab Emirates (UAE) and has similar findings. Mothers who breastfed exclusively longer showed a longer span of lactational amenorrhea, ranging from an average of 5.3 months in mothers who breastfed exclusively for only two months to an average of 9.6 months in mothers who did so for six months. Another factor shown to affect the length of amenorrhea was the mother's age. The older a woman was, the longer period of lactational amenorrhea she demonstrated. The same increase in length was found in multiparous women as opposed to primiparous. With regard to the use of breastfeeding as a form of contraception, most women who do not breastfeed will resume regular menstrual cycling within 1.5 to 2 months following parturition. Furthermore, the closer a woman's behavior is to the Seven Standards (see below) of ecological breastfeeding, the later (on average) her cycles will return. Overall, there are many factors including frequency of nursing, mother's age, parity, and introduction of supplemental foods into the infant's diet among others which can influence return of fecundity following pregnancy and childbirth and thus the contraceptive benefits of lactational amenorrhea are not always reliable but are evident and variable among women. Couples who desire spacing of 18 to 30 months between children can often achieve this through breastfeeding alone, though this is not a foolproof method as return of menses is unpredictable and conception can occur in the weeks preceding the first menses.
Although the first post-partum cycle is sometimes anovulatory (reducing the likelihood of becoming pregnant again before having a post-partum period), subsequent cycles are almost always ovulatory and therefore must be considered fertile. For women exclusively breastfeeding ovulation tends to return after their first menses after the 56 days postpartum time period. Supplementing nutritional intake can lead to an earlier return of menses and ovulation than exclusive breastfeeding. Nursing more frequently for a shorter amount of time was shown to be more successful in prolonging amenorrhea than nursing longer but less frequently. The continuing of breastfeeding, while introducing solids after 6 months, to 12 months were shown to have an efficiency rate of 92.6 – 96.3 percent in pregnancy prevention. Because of this some women find that breastfeeding interferes with fertility even after ovulation has resumed.
The Seven Standards: Phase 1 of Ecological Breastfeeding
Breastfeed exclusively for the first six months of life; don’t use other liquids and solids, not even water.
Pacify or comfort your baby at your breasts.
Don’t use bottles and don’t use pacifiers.
Sleep with your baby for night feedings.
Sleep with your baby for a daily-nap feeding.
Nurse frequently day and night, and avoid schedules.
Avoid any practice that restricts nursing or separates you from your baby.
Phase 1 is the time of exclusive breastfeeding and thus usually lasts six to eight months.
== Use as birth control ==
For women who follow the suggestions and meet the criteria (listed below), lactational amenorrhea method (LAM) is >98% effective during the first six months postpartum.
Breastfeeding must be the infant's only (or almost only) source of nutrition. Feeding formula, pumping instead of nursing, and feeding solids all reduce the effectiveness of LAM.
The infant must breastfeed at least every four hours during the day and at least every six hours at night.
The infant must be less than six months old.
The mother must not have had a period after 56 days post-partum (when determining fertility, bleeding prior to 56 days post-partum can be ignored).
And to take full advantage of LAM, it is best that the baby's face not be covered when feeding. Routinely covering the baby reduces the baby's access to oxygen and visual contact with the mother, which trains the baby to speed up the suckling process and thus reduces the time period, rendering LAM less effective.
If not combined with barrier contraceptives, spermicides, hormonal contraceptives, or intrauterine devices, LAM may be considered natural family planning by the Roman Catholic Church.
== Cross cultural use of lactational amenorrhea ==
The use of lactational amenorrhea method (LAM) can be seen across the world. It is used in many different societies to varying extents. LAM can be used by itself or in combination with other methods. There are multiple examples of LAM use covered in studies conducted about postpartum birth control methods in various countries and areas of the world. Additionally, the connection between LAM use and infant nutrition and health has been examined in different contexts. Beyond the physiological factors that influence lactational amenorrhea, cross cultural differences can help account for many of the variations in lactational amenorrhea.
In Turkey, exploration of LAM has exposed a distinct lack of knowledge surrounding the connection between lactational amenorrhea and birth control. However, these findings are contrasted with the fact that mothers demonstrated a desire to learn about LAM as a method of contraception. This lack of knowledge is not necessarily evident in other parts of the globe as exemplified in South-Eastern Hungary with the use of post-partum contraceptives. There is an imbalance of birth control method usage postpartum. LAM makes up nearly double the usage of other contraceptive usages. One of the primary factors influencing choice of contraceptive in this area is level of education. A higher level of education correlates to a bigger chance of utilizing effective contraception methods rather than LAM.
Nutrition and health of both the mother and infant are connected to the use of LAM in the international community. By promoting LAM, exclusive breastfeeding for the infant becomes more prominent in order to make LAM as effective as possible. In Egypt, this has been shown to combat poor nutritional practices of mothers. To make sure infants are getting fully enriching breast milk, mothers must take their own nutritional practices seriously, leading to an overall improvement of nutrition. An area in Kenya further provides evidence that there is a substantial link between proper nutrition and LAM, specifically with infants. This exclusive use of breastfeeding has a positive impact on preventing pregnancy as well as reducing child mortality. The promotion of LAM has shown an increase in breast feeding overall, resulting in better prospects of survival for infants.
== References ==
== Further reading ==
Chao, S. "The Effect of Lactation on Ovulation and Fertility." Clinics in Perinatology. U.S. National Library of Medicine, Mar. 1987. Web. 21 Nov. 2019
McGregor, James A. "Lactation and Contraception." SpringerLink. Springer, Boston, MA, 01 Jan. 1983. Web. 21 Nov. 2019.
Planned Parenthood. "Breastfeeding as Birth Control: Information About LAM." Planned Parenthood. N.p., n.d. Web. 21 Nov. 2019.
Shaaban, Mamdouh M. "Contraception with Progestogens and Progesterone during Lactation." The Journal of Steroid Biochemistry and Molecular Biology. Pergamon, 17 Jan. 2003. Web. 21 Nov. 2019. | Wikipedia/Lactational_amenorrhea_method |
Sex therapy is a therapeutic strategy for the improvement of sexual function and treatment of sexual dysfunction. This includes dysfunctions such as premature ejaculation and delayed ejaculation, erectile dysfunction, lack of sexual interest or arousal, and painful sex (vaginismus and dyspareunia); as well as problems imposed by atypical sexual interests (paraphilias), gender dysphoria (and being transgender), highly overactive libido or hypersexuality, a lack of sexual confidence, and recovering from sexual abuse (such as rape or sexual assault); and also includes sexual issues related to aging, illness, or disability.
== Practice ==
Modern sex therapy often integrates psychotherapeutic techniques and medical ones, such as Viagra (sildenafil) and Cialis (tadalafil) to increase erectile response and Paxil (paroxetine) to treat premature ejaculation. Sex therapists assist those experiencing problems in overcoming them, in doing so possibly regaining an active and healthy sex life. The transformative approach to sex therapy aims to understand the psychological, biological, pharmacological, relational, and contextual aspects of sexual problems.
Sex therapy requires rigorous evaluation that includes a medical and psychological examination. The reason is that sexual dysfunction may have a somatic base or a psychogenic basis. A clear example is erectile dysfunction (sometimes still called "impotence"), whose causes may include circulatory problems and performance anxiety. Sex therapy is frequently short term, with duration depending on the causes for therapy.
Sex therapy can be provided by licensed psychologists or physicians, who have undergone training and become certified. These trainings and certifications usually begin with a master's degree, and internship, and a license. This can take up to two years, and longer if a doctoral degree is desired.
Certified sex therapists do not have sexual contact with their clients. Sex therapy is distinct from sex surrogates. Whereas sex therapists discuss and instruct clients in sex-based exercises to be performed at home between sessions, sexual surrogates participate in the exercises with their clients as part of helping them to practice and develop improved skills. Therapists and surrogates sometimes collaborate on cases.
=== Symptoms ===
Sex therapy sessions are focused on the individual's symptoms rather than on underlying psychodynamic conflicts. The sexual dysfunctions which may be addressed by sex therapy include non-consummation, premature ejaculation, erectile dysfunction, low libido, unwanted sexual fetishes, sexual addiction, painful sex, or a lack of sexual confidence, assisting people who are recovering from sexual assault, problems commonly caused by stress, tiredness, and other environmental and relationship factors. Sex therapy can either be on an individual basis or with the sex partner. Sex therapy can be conducted with any adult client, including older adults, any gender expression, and LGBTQ-identified people.
A therapist's misunderstanding of these conflicts can lead to resistance or serve as a barrier to improving sexual dysfunctions that are directly or indirectly related to sex. The interest in sex therapy among couples has increased along with the number of sexuality educators, counselors, and therapists. Today, sexual problems are no longer regarded as symptoms of hidden deviant, pathological, or psychological defects in maturity or development. Sex therapy has also influenced the emergence of sexual medicine and exploring integrative approaches to sex therapy, in addition to reducing or eliminating sexual problems and increasing sexual satisfaction for individuals of all stages of life. Health therapists, educators, and counselors are conducting research and administering surveys to fully understand normative sexual function – what most people do and experience as they grow older and live longer.
== Aging and sexuality ==
Both physical and emotional transformation throughout various stages of life can affect the body and sexuality. The subsequent decline in hormone levels and changes in neurological and circulatory functioning may lead to sexual problems such as erectile dysfunction or vaginal pain. These physical changes often affect the intensity of youthful sex and may give way to more subdued responses during middle and later life. Issues with low libido and sexual dysfunction are usually considered to be a byproduct of old age. The emotional byproducts of maturity, however — increased confidence, better communication skills, and lessened inhibitions — can help create a richer, more nuanced, and ultimately satisfying sexual experience. During AARP's last surveys in 1999, 2004, and 2009 statistics show well-being among older adults has increased; however, overall sexual satisfaction has decreased. Nevertheless, older adults believed that an active sexual life offers great pleasure and contributes materially to overall emotional and physical health.
=== Older adults ===
Over the years, little attention has been paid to older adults and sexuality. As the population of older adults and life expectancy continue to grow, there is information about sex therapy but it is often not easily accepted. Cultural and sexual roles are always changing throughout the life-course. As people age, they are often viewed as asexual or as incapable of possessing sexual desires. The presence of sexual dysfunction during old age can be impacted by health problems. There are many endocrine, vascular and neurological disorders that may interfere in sexual function, along with some medications and surgeries. Older men experience changes that occur in sexual physiology and affect both erectile function and ejaculation. While older women experience physiological effects of aging after menopause, resulting in the decreased production of estrogen. This leads to increased vaginal dryness, general atrophy of vaginal tissue, and genital changes (reduced size of clitoral, vulvar, and labial tissue). Cognitive changes and decline is another factor that influences sexual activity. Dementia, Alzheimer's and mental health disorders may have an effect on sexual behavior, producing disinhibition or relationship difficulties with subsequent effects on couple's sexual relationships.
Sex therapy with older adults looks at factors which influence sexuality in older adults, including sexual desire, sexual activity, the value of sexuality, and health. It can include sensate focus, communication, and fantasy exercises as well as psychodynamic therapy.
Sex therapy for older adults is similar to sex therapy with other populations. It includes the use of water-based personal lubricants (for decreased vaginal lubrication), hormone therapy, and medications. Sex therapists working with older adults should know about sexuality and aging. They should also be aware of how stereotypes affect their clients. This is especially true for LGBT-identified clients.
Older adults may also need more education about their sexuality and sexual functioning. Curriculum for this includes communication, masturbation, body image, and spirituality. It also teaches about talking to a doctor about sexual activity. It is optimal that sex education for older adults includes information about sexually transmitted infections (STDs/STIs), such as HIV/AIDS.
== History ==
Sex therapy has existed in different cultures throughout time, including ancient India, China, Greece, and Rome. It has taken the form of manuals, spells, anaphrodisiacs or aphrodisiacs, and tantric yoga, among others. Much of sex therapy and sexual dysfunction in Western cultures was limited to scientific discussion, especially throughout the 19th century and into the early 20th century.
Sexologists such as Henry Havelock Ellis and Alfred Kinsey began conducting research in the area of human sexuality during the first half of the 20th century. This work was groundbreaking and controversial in the scientific arena.
In the 1950s, sex therapy was concerned with "controlling sexual expression" and repressing what was then-considered deviant behaviors, such as homosexuality or having sex too often. Masters and Johnson are credited with revolutionizing sex therapy in the mid-century and included couple therapy and behavioral interventions that focused on being present in the moment such as sensate focus exercises. Dr. Helen Singer Kaplan modified some of Masters and Johnson's ideas to better suit her outpatient practice, including introducing medication. Both integrated cognitive behavioral therapy into their practice and Kaplan used psychodynamic therapy as well. The combination of hypnotic procedures with humanistic psychodrama (Hans-Werner Gessmann 1976) is an option. The work of Jack Annon in 1976 also saw the creation of the PLISSIT model that sought to create a structured system of levels for the therapist to follow.
The mid-1980s saw the medicalization of sex therapy, with a primary focus on male sexual dysfunction. The 1990s brought penile injections and medications such as Viagra as well as the marketing of antidepressants for their delayed ejaculation side-effects. Hormone therapy was introduced to assist both male and female sexual dysfunction. Dilators were used to treat women with vaginismus and surgical procedures to increase the size of the vaginal opening and treat vulvar pain were also introduced.
== See also ==
Certified Sex Addiction Therapist
Certified Sex Therapist
List of sex therapists
Sensate focus
Sexual assistance
Society for Sex Therapy and Research
== References ==
Bibliography
Kaplan, Helen Singer, The New Sex Therapy: Active Treatment Of Sexual Dysfunctions, New York, Brunner/Mazel, 1974. ISBN 0-87630-083-2
Westberg, Marisol, "How to Become a Sex Therapist" | Wikipedia/Sex_therapy |
The diaphragm is a barrier method of birth control. It is moderately effective, with a one-year failure rate of around 12% with typical use. It is placed over the cervix with spermicide before sex and left in place for at least six hours after sex. Fitting by a healthcare provider is generally required.
Side effects are usually very few. Use may increase the risk of bacterial vaginosis and urinary tract infections. If left in the vagina for more than 24 hours toxic shock syndrome may occur. While use may decrease the risk of sexually transmitted infections, it is not very effective at doing so. There are a number of types of diaphragms with different rim and spring designs. They may be made from latex, silicone, or natural rubber. They work by blocking access to and holding spermicide near the cervix.
The diaphragm came into use around 1882. It is on the World Health Organization's List of Essential Medicines.
== Medical use ==
Before inserting or removing a diaphragm, one's hands should be washed to avoid introducing harmful bacteria into the vaginal canal.
The rim of a diaphragm is squeezed into an oval or arc shape for insertion. A water-based lubricant (usually spermicide) may be applied to the rim of the diaphragm to aid insertion. One teaspoon (5 mL) of spermicide may be placed in the dome of the diaphragm before insertion, or with an applicator after insertion.
The diaphragm must be inserted sometime before sexual intercourse, and remain in the vagina for 6 to 8 hours after a man's last ejaculation. For multiple acts of intercourse, it is recommended that an additional 5 mL of spermicide be inserted into the vagina (not into the dome—the seal of the diaphragm should not be broken) before each act. Upon removal, a diaphragm should be cleansed with mild soap and warm water before storage. The diaphragm must be removed for cleaning at least once every 24 hours and can be re-inserted immediately.
Oil-based products should not be used with latex diaphragms. Lubricants or vaginal medications that contain oil will cause the latex to rapidly degrade and greatly increases the chances of the diaphragm breaking or tearing.
Natural latex rubber will degrade over time. Depending on usage and storage conditions, a latex diaphragm should be replaced every one to three years. Silicone diaphragms may last much longer—up to ten years.
=== Effectiveness ===
The effectiveness of diaphragms, as of most forms of contraception, can be assessed two ways: method effectiveness and actual effectiveness. The method effectiveness is the proportion of couples correctly and consistently using the method who do not become pregnant. Actual effectiveness is the proportion of couples who intended that method as their sole form of birth control and do not become pregnant; it includes couples who sometimes use the method incorrectly, or sometimes not at all. Rates are generally presented for the first year of use. Most commonly the Pearl Index is used to calculate effectiveness rates, but some studies use decrement tables.
For all forms of contraception, actual effectiveness is lower than method effectiveness, due to several factors:
mistakes on the part of those providing instructions on how to use the method
mistakes on the part of the method's users
conscious user non-compliance with method
For instance, someone using a diaphragm might be fitted incorrectly by a health care provider, or by mistake remove the diaphragm too soon after intercourse, or simply choose to have intercourse without placing the diaphragm.
Contraceptive Technology reports that the method failure rate of the diaphragm with spermicide is 6% per year.
The actual pregnancy rates among diaphragm users vary depending on the population being studied, with yearly rates of 10% to 39% being reported.
Unlike some other cervical barriers, the effectiveness of the diaphragm is the same for women who have given birth as for those who have not.
=== Advantages ===
The diaphragm does not interfere with a woman's menstrual cycle, therefore, no reversal or waiting time is necessary if contraception is no longer wanted or needed.
The diaphragm only has to be used during intercourse. Many women, especially those who have sex less frequently, prefer barrier contraception such as the diaphragm over methods that require some action every day.
Like all cervical barriers, diaphragms may be inserted several hours before use, allowing uninterrupted foreplay and intercourse. Most couples find that neither partner can feel the diaphragm during intercourse.
The diaphragm is less expensive than many other methods of contraception.
=== Sexually transmitted infections ===
There is some evidence that the cells in the cervix are particularly susceptible to certain sexually transmitted infections (STIs). Cervical barriers such as diaphragms may offer some protection against these infections. However, research conducted to test whether the diaphragm offers protection from HIV found that women provided with both male condoms and a diaphragm experienced the same rate of HIV infection as women provided with male condoms alone.
Because pelvic inflammatory disease (PID) is caused by certain STIs, diaphragms may lower the risk of PID. Cervical barriers may also protect against human papillomavirus (HPV), the virus that causes cervical cancer, although the protection appears to be due to the spermicide used with diaphragms and not the barrier itself.
Diaphragms are also considered a good candidate as a delivery method for microbicides (preparations that, used vaginally, protect against STIs) that are currently in development.
== Side effects ==
Women (or their partners) who are allergic to latex should not use a latex diaphragm.
Diaphragms are associated with an increased risk of urinary tract infection (UTI). Urinating before inserting the diaphragm, and also after intercourse, may reduce this risk.
Toxic shock syndrome (TSS) occurs at a rate of 2.4 cases per 100,000 women using diaphragms, almost exclusively when the device is left in place longer than 24 hours.
The increase in risk of UTIs may be due to the diaphragm applying pressure to the urethra, especially if the diaphragm is too large, and causing irritation and preventing the bladder from emptying fully. However, the spermicide nonoxynol-9 is itself associated with increased risk of UTI, yeast infection, and bacterial vaginosis. For this reason, some advocate use of lactic acid or lemon juice based spermicides, which might have fewer side effects.
In the early 1920s, Marie Stopes claimed that when wearing a diaphragm, the vagina is stretched such that certain movements made by the woman for the benefit of the man were restricted by the diaphragm spring. In later years there was some discussion of this, with two authors supporting this concept and one opposed. One of them argued in the later 1920s-1930s that while the muscle movement by women is restricted it does not make all that much difference since most "women (in the 1920s) are not able to operate their pelvic muscles voluntarily to the best advantage" (during sex). However, Stopes anticipated this rebuttal, and in so many words classified it as a lame excuse.
== Use without spermicide ==
It has been suggested that, for women who experience side effects from the spermicide nonoxynol-9, it may be acceptable to use the diaphragm without any spermicide. One study found an actual pregnancy rate of 24% per year in women using the diaphragm without spermicide; however, all women in this study were given a 60 mm diaphragm rather than being fitted by a clinician. Other studies have been small and given conflicting results. Insufficient studies have been conducted to conclusively determine effectiveness without spermicide. The current recommendation is still for all diaphragm users to use spermicide with the device.
== Types ==
Diaphragms are available in diameters of 50 mm to 105mm (about 2–4 inches). They are available in two different materials: latex and silicone. Diaphragms are also available with different types of springs in the rim.
An arcing spring folds into an arc shape when the sides are compressed. This is the strongest type of rim available in a diaphragm, and may be used by women with any level of vaginal tone. Unlike other spring types, arcing springs may be used by women with mild cystocele, rectocele, or retroversion. Arcing spring diaphragms may be easier to insert correctly than other spring types.
A coil spring flattens into an oval shape when the sides are compressed. This rim is not as strong as the arcing spring, and may only be used by women with average or firm vaginal tone. If an arcing spring diaphragm is uncomfortable for a woman or, during intercourse, her partner, a coil spring may prove more satisfactory. Unlike the arcing spring diaphragms, coil springs may be inserted with a device called an introducer.
A flat spring is much like a coil spring, but thinner. This type of rim may only be used by women with firm vaginal tone. Flat spring diaphragms may also be inserted with an introducer for women uncomfortable using their hands. Ortho used to manufacture a flat-spring diaphragm called the Ortho White. Reflexions also manufactured a flat-spring diaphragm up until 2014.
There are a number of variations. The SILCS diaphragm is made of silicone, has an arcing spring, and a finger cup is molded on one end for easy removal. The Duet disposable diaphragm is made of dipped polyurethane, pre-filled with BufferGel (BufferGel is currently in clinical trials as a spermicide and microbicide). Both the SILCS and Duet diaphragms come in only one size.
=== Fitting ===
Diaphragms usually come in different sizes and require a fitting appointment with a health care professional to determine which size a woman should wear. Single size diaphragms that do not require fitting also exist.
A correctly fitting diaphragm will cover the cervix and rest snugly against the pubic bone. A diaphragm that is too small might fit inside the vagina without covering the cervix, or might become dislodged from the cervix during intercourse or bowel movements. It is also more likely that a woman's partner will feel the anterior rim of a diaphragm that is too small during intercourse. A diaphragm that is too large will place pressure on the urethra, preventing the bladder from emptying completely and increasing the risk of urinary tract infection. A diaphragm that is too large may also cause a sore to develop on the vaginal wall.
Diaphragms should be re-fitted after a weight change of 4.5 kg (10 lb) or more. The traditional clinical guideline is that a decrease in weight may cause a woman to need a larger size, although the strength of this relationship has been questioned.
Diaphragms should also be re-fitted after any pregnancy of 14 weeks or longer. Full-term vaginal delivery especially will tend to increase the size diaphragm a woman needs, although the changes to the pelvic floor during pregnancy mean even women who experience second-trimester miscarriage, or deliver by C-section, should be refitted.
Vaginal tenting, an increase in the length of the vagina, occurs during arousal. This means that during intercourse, the diaphragm will not fit snugly against the pubic bone because it is carried higher up the vaginal canal by the movement of the cervix. If the diaphragm is inserted after arousal has begun, extra care must be taken to ensure the device is covering the cervix.
A woman might be fitted with a different size diaphragm depending on where she is in her menstrual cycle. It is common for a woman to wear a larger diaphragm during menstruation. It has been speculated that a woman may be fitted with a larger size diaphragm when she is near ovulation. The correct size for a woman is the largest size that she can wear comfortably throughout her cycle.
In the United States, diaphragms are available by prescription only. Many other countries do not require prescriptions.
== Mechanism of action ==
The spring in the rim of the diaphragm forms a seal against the vaginal walls. The diaphragm covers the cervix, and physically prevents sperm from entering the uterus through the cervical canal.
Traditionally, the diaphragm has been used with spermicide, and it is widely believed that the spermicide is a significant factor in the effectiveness of the diaphragm. However, some have asserted that the diaphragm's mechanism of action is primarily as a physical barrier and that a diaphragm is effective without spermicides, but insufficient studies have been conducted to prove this.
It is widely taught that additional spermicide must be placed in the vagina if intercourse occurs more than six hours after insertion. However, there has been very little research on how long spermicide remains active within the diaphragm. One study found that spermicidal jelly and creme used in a diaphragm retained its full spermicidal activity for twelve hours after placement of the diaphragm.
It has long been recommended that the diaphragm be left in place for at least six or eight hours after intercourse. No studies have been done to determine the validity of this recommendation, however, and some medical professionals have suggested intervals of four hours or even two hours are sufficient to ensure efficacy. One manufacturer of contraceptive sponges recommends leaving the sponge in place for only two hours after intercourse. However, such use of the diaphragm (removal before 6 hours post-intercourse) has never been formally studied, and cannot be recommended.
It has been suggested that diaphragms be dispensed as a one-size-fits-all device, providing all women with the most common size (70 mm). However, only 33% of women fitted for a diaphragm are prescribed a 70 mm size, and correct sizing of the diaphragm is widely considered necessary.
== History ==
The idea of blocking the cervix to prevent pregnancy is thousands of years old. Various cultures have used cervix-shaped devices such as oiled paper cones or lemon halves, or have made sticky mixtures that include honey or cedar resin to be applied to the cervical opening. However, the diaphragm—which stays in place because of the spring in its rim, rather than hooking over the cervix or being sticky—is of more recent origin.
An important precursor to the invention of the diaphragm was the rubber vulcanization process, patented by Charles Goodyear in 1844. In the 1880s, a German gynecologist, Wilhelm P. J. Mensinga, published the first description of a rubber contraceptive device with a spring molded into the rim. Mensinga wrote first under the pseudonym C. Hasse, and the Mensinga diaphragm was the only brand available for many decades. In the United States, the physician Edward Bliss Foote designed and sold an early form of occlusive pessary under the name "womb veil" starting in the 1860s.
American birth control activist Margaret Sanger fled to Europe in 1914 to escape prosecution under the Comstock laws, which prohibited sending contraceptive devices, or information about contraception, through the mail. Sanger learned about the diaphragm in the Netherlands and introduced the product to the United States when she returned in 1916. Sanger and her second husband, Noah Slee, illegally imported large quantities of the devices from Germany and the Netherlands. In 1925, Slee provided funding to Sanger's friend Herbert Simonds, who used the funds to found the first diaphragm manufacturing company in the U.S., the Holland-Rantos Company.
Diaphragms played a role in overturning the federal Comstock Act of 1873. In 1932, Sanger arranged for a Japanese manufacturer to mail a package of diaphragms to a New York physician who supported Sanger's activism. U.S. Customs confiscated the package and Sanger helped file a lawsuit. In 1936, in the court case United States v. One Package of Japanese Pessaries, a federal appellate court ruled that the package could be delivered.
Although in Europe, the cervical cap was more popular than the diaphragm, the diaphragm became one of the most widely used contraceptives in the United States. In 1940, one-third of all U.S. married couples used a diaphragm for contraception. The number of women using diaphragms dropped dramatically after the 1960s introduction of the intrauterine device and the combined oral contraceptive pill. In 1965, only 10% of U.S. married couples used a diaphragm for contraception. That number has continued to fall, and in 2002 only 0.2% of American women were using a diaphragm as their primary method of contraception.
In 2014 Janssen Pharmaceuticals announced the discontinuation of the Ortho-All Flex Diaphragm, making it very difficult for women in the U.S. to have that option as a birth-control method.
The single-sized, silicone diaphragm was developed by PATH during the late 2000s. It was licensed to Kessel Marketing & Vertriebs GmbH of Frankfurt, Germany, which began to market it as the Caya Diaphragm. The diaphragm was approved for contraception in Europe in 2013 and in the United States the following year. Since then, Kessel has also developed a traditionally circular, multi-sized diaphragm made from the same materials that they released in Germany in 2020 under the name Singa.
== Society and culture ==
=== Economics ===
In the United Kingdom, they cost the National Health Service less than £10 each. In the United States, they cost about US$15 to $75 and are the birth control method of 0.3% of women. These costs do not include that of spermicide.
== References ==
== Further reading ==
Marks, Olivia (10 July 2015). "Is the diaphragm making a comeback?". The Guardian.. | Wikipedia/Diaphragm_(birth_control) |
Long-acting reversible contraceptives (LARC) are methods of birth control that provide effective contraception for an extended period without requiring user action. They include hormonal and non-hormonal intrauterine devices (IUDs) and subdermal hormonal contraceptive implants. They are the most effective reversible methods of contraception because their efficacy is not reliant on patient compliance. The failure rates of IUDs and implants is less than 1% per year.
LARCs are often recommended to people seeking convenient and cost effective contraception. In one study, LARC users saved thousands of dollars over a five-year period compared to those who buy condoms and birth control pills. LARCs can generally be safely and effectively used by people of any body weight, adolescents, and people who have not yet had children.
In 2008, the American College of Obstetrics and Gynecologists (ACOG) launched The Long-Acting Reversible Contraception Program with the intention to reduce rates of unintended pregnancy by promoting LARCs, often referred to as a "LARC-first" model. Rates of LARC use in the United States rose steadily in that time frame, from 3.7% in 2007 to 10% in 2019. LARC methods are most popular amongst people in their late teens and early twenties. LARC use varies globally, with different regions reporting different use rates. An estimated 161 million people of reproductive age use an IUD and an additional 25 million use an implant; this is 19.4% of the estimated global population of women of reproductive age.
== Methods ==
LARC methods include IUDs and the subdermal implant.
IUDs, also sometimes referred to as IUS (intrauterine system) or IUC (intrauterine contraception), can come in hormonal or nonhormonal varieties.
Hormonal intrauterine devices are sold under the brand names Mirena, Skyla, Liletta, and others.
Nonhormonal intrauterine device with copper are sold under the brand names copper-T and Paraguard.
Subdermal contraceptive implant are sold under the brand names Nexplanon, Implanon, Norplant, Jadelle, and others.
== Medical use ==
=== Contraception ===
LARCs have higher rates of efficacy than do other forms of contraception. This difference is likely due to the difference between "perfect use" and "typical use". Perfect use indicates complete adherence to medication schedules and guidelines. Typical use describes effectiveness in real-world conditions, where patients may not fully adhere to medication regimens. LARC methods require little to no user action after insertion; therefore, LARC perfect use failure rates are the same as their typical use failure rates. LARC failure rates are comparable to those of sterilization. LARCs and sterilization differ in their reversibility.
The implant has a 0.05% failure rate in the first year of use, the levonorgestrel (hormonal) IUD has a 0.1% failure rate in the first year of use, and the copper IUD has a 0.8% failure rate in first year of use. These rates are comparable to those of permanent sterilization procedures, leading to conclusions that LARCs should be offered as "first-line contraception."
=== Additional Uses ===
LARCs can also be used to treat other conditions, primarily by regulating or stopping the bleeding portion of a user's menstrual cycle. LARCs may be used to treat endometriosis and heavy menstrual bleeding. They can also be useful in treating painful menstruation.
Additionally, a copper IUD can be used as emergency contraception if inserted within five days of unprotected sex. This timeframe may be extended if the date of ovulation is known; the copper IUD must be inserted within 5 days of ovulation.
== Side effects and risks ==
Side effects and risks for LARCs vary by type of LARC, with hormonal IUDs, non-hormonal IUDs, and implants all entailing different side effects and risks.
=== Side effects ===
Hormonal IUDs have similar side effects to other forms of hormonal contraception, such as combined and progesterone only oral contraceptives. Hormonal IUDs most frequently cause irregular menstrual bleeding. Other side effects include acne, breast tenderness, headaches, nausea, and mood changes.
The most common side effects of non-hormonal or copper IUDs are increased pain and heavy bleeding during menstruation, and spotting between menstruation. Impacts on menstruation may decrease over the lifespan of the IUD, but spotting between menstruation may become more frequent over time. For some users, these side effects lead them to discontinue use.
The most common side effect of the contraceptive implant is irregular bleeding, which includes both reduced and increased levels of bleeding. Other side effects include mood changes and mild insulin resistance.
=== Risks ===
IUD use carries some additional risks. Both hormonal and non-hormonal IUDs may lead to developing non-cancerous ovarian cysts. It is also possible that an IUD may be expelled (fall out) from the uterus. The IUD may also perforate (tear) the uterine wall. This is extremely rare and a medical emergency.
== Society and culture ==
=== Cost and benefit ===
All LARCs are designed to last for at least three years, with some options (Paraguard Copper IUD) lasting for at least ten years. Although they have higher up-front costs (out-of-pocket costs can range between $500 and $1300), that cost purchases coverage for longer than other contraceptive methods, which are often purchased on a monthly basis (for hormonal birth control methods like pills, patches, or rings.) When accounting for upfront costs, failure rates, and side effects, researchers estimate that the most cost effective means of contraception are the Copper IUD, vasectomy, and the levonorgestrel IUD (such as a Mirena). One researcher estimates that use of the levonorgestrel IUD can be up to 31% cheaper than using non-LARC methods such as birth control pills, patch, ring, or injectables. Regardless, the initial out of pocket cost is still too high for many patients, and is one of the biggest barriers to LARC use. Studies conducted in California and St. Louis have shown that rates of LARC usage are dramatically higher when the costs of the methods are either covered or removed.
The Colorado Family Planning Initiative (CPFI), a six-year $23 million privately funded program to expand access to LARCs, This program specifically provided no-cost LARCs to low-income women across the state of Colorado, with the intention of preventing unintended pregnancies within specific groups deemed at high-risk of unintended pregnancy. This program decreased unplanned adolescent pregnancies in Colorado by about half. There was a similar decline of unplanned pregnancies in unmarried women under 25 who have not finished high school. Use of LARC methods by children of child-bearing age in the state increased to 20% during the 2009–2014 period. A 2017 study found that CPFI "reduced the teen birth rate in counties with clinics receiving funding by 6.4 percent over five years. These effects were concentrated in the second through fifth years of the program and in counties with relatively high poverty rates."
=== Promotion ===
The United Kingdom Department of Health has actively promoted LARC use since 2008, particularly for young people; following on from the October 2005 National Institute for Health and Clinical Excellence guidelines, which promoted LARC provision in the United Kingdom, accurate and detailed counseling for women about these methods, and training of healthcare professionals to provide these methods. Giving advice on these methods of contraception has been included in the 2009 Quality and Outcomes Framework "good practice" for primary care.
The use of long-acting reversible contraceptives in the United States has increased nearly fivefold from 1.5% in 2002 to 7.2% in 2011–2013. Increasing access to long-acting reversible contraceptives was listed by the Centers for Disease Control and Prevention as one of the top public health priorities for reducing teen pregnancy and unintended pregnancy in the United States. One study of female family planning providers showed that they were significantly more likely to use LARCs than the general population (41.7% compared to 12.0%) suggesting that the general population has less information or access to LARCs.
=== LARC-First models and backlash ===
Guidelines released in 2009 by the American College of Obstetricians and Gynecologists (ACOG) state that LARC methods are considered to be the first-line option for birth control in the United States, and are recommended for the majority of women. According to the CDC Medical Eligibility Criteria for Contraceptive Use, LARC methods are recommended for the majority of women who have had their first menstruation, regardless of whether they have had any pregnancies. The American Academy of Pediatrics (AAP) in a policy statement and technical report published in October 2014 recommended LARC methods for adolescents.
In the years since ACOG made these recommendations, many researchers have evaluated the impact of the LARC-first model. Because it prioritized the importance of effectiveness of method in contraceptive counseling, patient preferences and priorities were not given adequate attention within contraceptive counseling. Researchers have found that patients experience over-enthusiasm about a particular method as coercive. ACOG practitioners have since come forward with an attempt at re-balancing recommendations to center patient needs and desires in contraceptive counseling. The organization has also formally denounced coercive contraceptive practices, including those that incentivize use of contraception, incentivize use of a particular type of contraception, or make it harder to discontinue use of contraception.
== See also ==
Contraceptive vaginal ring
== References ==
== External links ==
UK National Health Service Long-acting Reversible Contraception Guidelines
Long-acting reversible contraception: the effective and appropriate use of long-acting reversible contraception
Increasing Use of Contraceptive Implants and Intrauterine Devices To Reduce Unintended Pregnancy from the American Congress of Obstetricians and Gynecologists | Wikipedia/Long-acting_reversible_birth_control |
Drug trafficking organizations are defined by the United States Department of Justice as, "complex organizations with highly defined command-and-control structures that produce, transport, and/or distribute large quantity "Law enforcement reporting indicates that Mexican DTOs maintain drug distribution networks, or supply drugs to distributors, in at least 230 U.S. cities." The use of weapons and fear are commonplace in trafficking which often lead to other crimes in the process. The structures of many of these organizations are of a para-military nature using armed combatants to protect their stock of illegal drugs from growth to delivery.
== History ==
In 1914, the Harrison Narcotic Act was passed by congress making a medical prescription necessary for products with high levels of opiate or narcotics." With laws against the use of un-prescribed drugs such as opium, cocaine, morphine, and heroin now in effect, the black market grew to continue supply to addicted or prospective users. Rising domestic enforcement of illegal growing and production operations, coupled with increasing legislation against illegal drugs, forced suppliers outside the country. Drug trafficking organizations from nations with lesser, or no drug laws emerged with the opportunity to make large profits from illegal trafficking into the United States. These organized crime syndicates would use any means necessary to exploit the weak border protection of the US. The drugs were shipped, flown, and trucked into the country and distributed from within. In many cases, "American mercenaries provided their services as pilots making trips between over 150 clandestine landing strips in South America and the US. In a 1986 Report from the President's Commission on Organized Crime, it was believed that nearly 2/3 of the cocaine from Colombia was flown into the country."
Rampant drug epidemics and rising gang dealing would eventually lead to a massive operationalization of drug enforcement. The US formed federal agencies and initiatives such as the "Drug Enforcement Administration (DEA) in 1973, and High Intensity Drug Trafficking Area centers with the Anti-Drug Abuse Act of 1988, coordinating efforts to slow the flow across borders and within the country." These agencies, along with academics, would formally define the groups that traffic drugs and study their operations.
== Organization and structure ==
=== Structure ===
Over the past few decades, drug trafficking organizations have increased in number and diversified in structure. They range from family based operations in which secrecy is essential, and where trafficking of large shipments are discreetly sent to associates across the border, to organizations involving hundreds of players with different roles. This varying structure can often make it difficult to identify the groups as each has a different MO and scale. In 1998, Mangai Natarajan, a professor at John Jay College of Criminal Justice, "studied court records of 39 trafficking organizations in New York City to classify drug syndicates into four main types. "Freelance" networks are composed of small nonhierarchical entrepreneurial groupings of individuals; "family businesses" are cohesive organizations with clear structure and authority and trust based on family ties; "communal businesses" are flexible organizations bound together by a common tie such as ethnicity, religion, nationality, or neighborhood residence; and "corporations" are large organizations in which there is a formal hierarchy and a well-defined division of labor." While these "corporations" are obviously the most organized, they often take years of investigation to trace up to the head operator. Many times these organizations are run from outside the country and therefore extradition and conflicting laws may prohibit the investigation. Another perspective argues that DTOs are politico-military groups that operate in failed states and have political agendas. Situations such as Mexico and Afghanistan today may support this claim, and perhaps, extend further connecting funds to terrorist groups.
=== Mexican DTOs ===
Mexican drug trafficking organizations have taken control of the US market in recent years, superseding Dominican and Colombian groups that held it for decades. These groups began as hierarchical with clear and defined leadership and a ladder of command down to the street dealer. In response to increasing law enforcement efforts and understanding of this system, many Mexican DTOs have shifted their command structure to an equally organized, but more independent system of decentralized cells. According to a High Intensity Drug Trafficking Areas Initiative (HIDTA) in the Midwest, the Mexican DTOs have "compartmentalized duties, employed advanced security and communications techniques, gathered intelligence, and used violence and intimidation to control organization members and secure smuggling territories." With a state of virtual lawlessness, futile domestic enforcement efforts, and rampant corruption fueled by the drug money, Mexico has grown into a massive drug producer. Production is unmatched when it comes to marihuana, heroin, and cocaine with methamphetamines an increasing trend.
=== Colombian and Dominican DTOs ===
Colombian and Dominican DTOs operate in hierarchical command structures and often launder money into non-drug legitimate industries such as real estate and high income businesses as an investigation by ICE learned in 2010 where a multibillion-dollar Colombian DTO was taken down. Controlling the US market for many years, these groups established undetectable transportation techniques and became deeply connected to domestic gangs. The insurgence of Mexican DTOs has brought increased violence and competition for large cities and territory control. Heroin and cocaine are the primary drugs produced in the countries which have been under the control of cartels for decades.
=== Asian DTOs ===
Asian DTOs have filled in the gaps left by the major players by producing and trafficking MDMA known commonly on the street as ecstasy or X. "While once a competitive supplier of heroin, the groups have avoided strife by targeting the high potency marijuana market growing in both Canada and the US to avoid border raids."
== Impact of DTOs ==
=== Finance, violence and terrorism ===
While an exact financial figure is not known to US authorities, DTOs are believed to make tens of billions of dollars annually depending on size of the organization. With this staggering income from illegal trade, the longevity and persistence of these organizations is understandable. For groups based in economically struggling regions, the illegal trafficking of drugs is a tempting and extremely profitable illegitimate business with little domestic risk. A variety of methods are used to conceal and move the cash made from the network of drug deals. Money laundering techniques involve the wiring and constant movement of funds from different banks and accounts. This technique makes tracking the money more difficult, and can cost banks millions in losses each year.
Aside from financial detriment, these groups can be very violent extending their police record to countless offences. In a constant struggle for territory and control of the market, DTOs will not hesitate to use deadly force against rival organizations, or threats to their business. The use of automatic weapons, threats, and bribery are common in maintaining control. "Narcoterrorism" is not a new threat but has become a domestic fear for the US after the attacks on September 11. With the formation of terrorism task forces and intelligence community initiatives, a greater understanding of the relationship between drug trade and terrorism has taken place.
Many terrorist organizations have the drug trade as their major income - for instance the Taliban controlled 96% of Afghanistan's poppy fields and made opium its largest source of taxation which became one of the mainstays of Taliban income and their war economy. According to Rashid, "drug money funded the weapons, ammunition and fuel for the war." In The New York Times, the Finance Minister of the United Front, Wahidullah Sabawoon, declared the Taliban had no annual budget but that they "appeared to spend US$300 million a year, nearly all of it on war." He added that the Taliban had come to increasingly rely on three sources of money: "poppy, the Pakistanis and bin Laden." According to Alfred McCoy, during the Cold War the CIA provided Afghan drug lord allies such as Gulbuddin Hekmatyar with transport, arms, and political protection in the fight against Soviet forces in Afghanistan. According to Loretta Napoleoni terrorism later shifted from being mainly state sponsored to gaining financial independence from their sponsors and becoming self-financed.
In a CBS news article, the Chief of Operations for the US Drug Enforcement Administration Michael Braun called "groups like the FARC, the Taliban, Hamas and Hezbollah: "hybrids" stating that they are one part terrorist organization, and are becoming one part global drug trafficking cartel." With this new "hybrid" threat, the violence aimed at political impact meets the already violent world of drug trafficking in a perfect storm. These narco-terrorist groups have been linked to car bombings, hostage situations, and mass killings of police and politicians which opposed the operation and could perhaps pose the greatest threat to the US in the future.
=== Gang involvement ===
Operationally, DTOs rely on street gangs to distribute the product to their customers. This collaboration supports turf wars between rival gangs like the Bloods and Crips that ensures their participation in the drug trade. These gangs which make headlines daily, rely on the illegal drug trade to support their gangs across the US. The money generated by this process, among other factors, draws youth into the gang lifestyle continuing the cycle of violence on the street.
== Combating drug trafficking organizations ==
=== Enforcement ===
With emerging involvement in these organizations, law enforcement agencies from all levels have stepped up operations against high intensity drug trafficking. Beginning with Vice units in Florida and other border states, law enforcement has grown exponentially in counter narcotics. Currently there is a large network of agencies, police, military, initiatives, and even private sector involvement to combat DTOs. Federal agencies such as the DEA, FBI, ICE, Border Patrol, and even the National Guard, work independently but cohesively to analyze and investigate organizations with the most impact. These agencies are dependent on local and state law enforcement officers who have the street interactions with members of the drug world. This data is collected and disseminated to initiatives such as HIDTAs which were formed as switchboards for drug Intel in target regions of the US. Using a wealth of knowledge, and ever improving technology in networks and analysis, law enforcement efforts finding greater success in dismantling organizations in the US.
=== Public health ===
Another approach has been initiated using campaigns for anti drug use in an attempt to reduce the demand for illegal drugs from within. This public health approach utilized TV programs and advertisements, as well as D.A.R.E. programs which are aimed at youth with the hope of prevention before enforcement.
== References == | Wikipedia/Drug_trafficking_organizations |
The list of countries by homicide rate is derived from United Nations Office on Drugs and Crime (UNODC) data, and is expressed in number of deaths per 100,000 population per year. For example, a homicide rate of 30 out of 100,000 is presented in the table as "30", and corresponds to 0.03% of the population dying by homicide. The reliability of underlying national murder rate data may vary. Only UNODC-vetted data is used in the main table to maintain consistency. In some cases, it may not be as up to date as other sources.
Homicide rates may be under-reported for political reasons.
A study undertaken by the Geneva Declaration on Armed Violence and Development estimated that there were approximately 490,000 intentional homicides globally in 2004, for a rate of 7.6 per 100,000. UNODC calculated a global estimated rate of 6.9 per 100,000 in 2010; 6.2 per 100,000 in 2012; 6.1 per 100,000 in 2017; and a rate of 5.61 per 100,000 for 2022.
== Definition ==
Intentional homicide is defined by the United Nations Office on Drugs and Crime (UNODC) in its Global Study on Homicide report thus:
Within the broad range of violent deaths, the core element of intentional homicide is the complete liability of the direct perpetrator, which thus excludes killings directly related to war or conflicts, self-inflicted death (suicide), killings due to legal interventions or justifiable killings (such as self-defence), and those deaths caused when the perpetrator was reckless or negligent but did not intend to take a human life (non-intentional homicide).
Though some discrepancies exist in how specific categories of intentional killings are classified, the definitions used by countries to record data are generally close to the UNODC definition, making the homicide rates highly comparable at the international level. UNODC uses the homicide rate as a proxy for overall violence, as this type of crime is one of the most accurately reported and internationally comparable indicators.
Figures from the Global Study on Homicide are based on the UNODC Homicide Statistics dataset, which is derived from the criminal justice or public health systems of a variety of countries and territories. The homicide rates derived from criminal justice data (typically recorded by police authorities) and the public health system data (recorded when the cause of death is established) may diverge substantially for some countries. The two sources usually match in the Americas, Europe and Oceania, but there are large discrepancies for the three African countries reporting both sources. For the 70 countries in which neither source was made available, figures were derived from WHO statistical models.
Deaths resulting from an armed conflict between states are never included in the count. Killings caused by a non-international armed conflict may or may not be included, depending on the intensity of hostilities and whether it is classified as 'civil unrest' or a clash between organized armed groups.
== UNODC's global study ==
All data in this section comes from the United Nations Office on Drugs and Crime (UNODC) website.
=== By region ===
Rates vary widely within regions. See info on secondary sorting within regions and subregions below.
=== By country, region, or dependent territory ===
The regions and subregions in the table are based on the United Nations geoscheme since the table sources are United Nations Office on Drugs and Crime (UNODC) reports. The U.N. recognizes that variability in the quality and integrity of data provided by certain countries may minimize country murder rates. Go to the more detailed country info in the references, and the country links in the table for more info.
Table has a total yearly count of homicides for each country. Rates are calculated per 100,000 inhabitants. Rates are to the 3rd decimal place in order to separate countries with low homicide rates.
Note: When the regions or subregions are sorted the countries are also alphabetically sorted within those regions or subregions. Then shift-click rate or count column heads to secondarily sort countries by rates or counts within the regions or subregions previously sorted.
Note: Table last fully updated from data retrieved 24 November 2024 from UNODC. Individual countries updated since then.
Note: Only UNODC-vetted data is used in the table.
Asterisk (*) in Location column indicates a Crime in LOCATION article.
== Other multi-country studies ==
A 2024 study by InSight Crime revealed that the Turks and Caicos Islands had the highest homicide rate in Latin America and the Caribbean. Haiti ranked second, followed by St. Kitts and Nevis in third place.
== See also ==
== References ==
== Sources ==
Global Study on Homicide 2013: Trends, Contexts, Data (PDF). Vienna: United Nations Office on Drugs and Crime. March 2014. ISBN 9789210542050. Look for page numbers on the bottom of pages, and ignore the incorrect page numbers provided by your PDF reader.
== Further reading ==
The Homicide Monitor map. Made by Brazil-based think tank, The Igarapé Institute.
== External links == | Wikipedia/Murder_rate |
Addiction is a neuropsychological disorder characterized by a persistent and intense urge to use a drug or engage in a behavior that produces natural reward, despite substantial harm and other negative consequences. Repetitive drug use can alter brain function in synapses similar to natural rewards like food or falling in love in ways that perpetuate craving and weakens self-control for people with pre-existing vulnerabilities. This phenomenon – drugs reshaping brain function – has led to an understanding of addiction as a brain disorder with a complex variety of psychosocial as well as neurobiological factors that are implicated in the development of addiction. While mice given cocaine showed the compulsive and involuntary nature of addiction, for humans this is more complex, related to behavior or personality traits.
Classic signs of addiction include compulsive engagement in rewarding stimuli, preoccupation with substances or behavior, and continued use despite negative consequences. Habits and patterns associated with addiction are typically characterized by immediate gratification (short-term reward), coupled with delayed deleterious effects (long-term costs).
Examples of substance addiction include alcoholism, cannabis addiction, amphetamine addiction, cocaine addiction, nicotine addiction, opioid addiction, and eating or food addiction. Behavioral addictions may include gambling addiction, shopping addiction, stalking, pornography addiction, internet addiction, social media addiction, video game addiction, and sexual addiction. The DSM-5 and ICD-10 only recognize gambling addictions as behavioral addictions, but the ICD-11 also recognizes gaming addictions.
== Signs and symptoms ==
Signs and symptoms of drug addiction can vary depending on the type of addiction. Symptoms may include:
Continuation of drug use despite the knowledge of consequences
Disregarding financial status when it comes to drug purchases
Ensuring a stable supply of the drug
Needing more of the drug over time to achieve similar effects
Social and work life impacted due to drug use
Unsuccessful attempts to stop drug use
Urge to use drug regularly
Other signs and symptoms can be categorized across relevant dimensions:
== Substance addiction ==
=== Drug addiction ===
Drug addiction, which belongs to the class of substance-related disorders, is a chronic and relapsing brain disorder that features drug seeking and drug abuse, despite their harmful effects. This form of addiction changes brain circuitry such that the brain's reward system is compromised, causing functional consequences for stress management and self-control. Damage to the functions of the organs involved can persist throughout a lifetime and cause death if untreated. Substances involved with drug addiction include alcohol, nicotine, marijuana, opioids, cocaine, amphetamines, and even foods with high fat and sugar content. Addictions can begin experimentally in social contexts and can arise from the use of prescribed medications or a variety of other measures.
Drug addiction has been shown to work in phenomenological, conditioning (operant and classical), cognitive models, and the cue reactivity model. However, no one model completely illustrates substance abuse.
Risk factors for addiction include:
Aggressive behavior (particularly in childhood)
Availability of substance
Community economic status
Experimentation
Epigenetics
Impulsivity (attentional, motor, or non-planning)
Lack of parental supervision
Lack of peer refusal skills
Mental disorders
Method substance is taken
Usage of substance in youth
=== Food addiction ===
The diagnostic criteria for food or eating addiction has not been categorized or defined in references such as the Diagnostic and Statistical Manual of Mental Disorders (DSM or DSM-5) and is based on subjective experiences similar to substance use disorders. Food addiction may be found in those with eating disorders, though not all people with eating disorders have food addiction and not all of those with food addiction have a diagnosed eating disorder. Long-term frequent and excessive consumption of foods high in fat, salt, or sugar, such as chocolate, can produce an addiction similar to drugs since they trigger the brain's reward system, such that the individual may desire the same foods to an increasing degree over time. The signals sent when consuming highly palatable foods have the ability to counteract the body's signals for fullness and persistent cravings will result. Those who show signs of food addiction may develop food tolerances, in which they eat more, despite the food becoming less satisfactory.
Chocolate's sweet flavor and pharmacological ingredients are known to create a strong craving or feel 'addictive' by the consumer. A person who has a strong liking for chocolate may refer to themselves as a chocoholic.
Risk factors for developing food addiction include excessive overeating and impulsivity.
The Yale Food Addiction Scale (YFAS), version 2.0, is the current standard measure for assessing whether an individual exhibits signs and symptoms of food addiction. It was developed in 2009 at Yale University on the hypothesis that foods high in fat, sugar, and salt have addictive-like effects which contribute to problematic eating habits. The YFAS is designed to address 11 substance-related and addictive disorders (SRADs) using a 25-item self-report questionnaire, based on the diagnostic criteria for SRADs as per DSM-5. A potential food addiction diagnosis is predicted by the presence of at least two out of 11 SRADs and a significant impairment to daily activities.
The Barratt Impulsiveness Scale, specifically the BIS-11 scale, and the UPPS-P Impulsive Behavior subscales of Negative Urgency and Lack of Perseverance have been shown to have relation to food addiction.
== Behavioral addiction ==
The term behavioral addiction refers to a compulsion to engage in a natural reward – which is a behavior that is inherently rewarding (i.e., desirable or appealing) – despite adverse consequences. Preclinical evidence has demonstrated that marked increases in the expression of ΔFosB through repetitive and excessive exposure to a natural reward induces the same behavioral effects and neuroplasticity as occurs in a drug addiction.
Addiction can exist without psychotropic drugs, an idea that was popularized by psychologist Stanton Peele. These are termed behavioral addictions. Such addictions may be passive or active, but they commonly contain reinforcing features, which are found in most addictions. Sexual behavior, eating, gambling, playing video games, and shopping are all associated with compulsive behaviors in humans and have been shown to activate the mesolimbic pathway and other parts of the reward system. Based on this evidence, sexual addiction, gambling addiction, video game addiction, and shopping addiction are classified accordingly.
== Causes ==
=== Personality theories ===
Personality theories of addiction are psychological models that associate personality traits or modes of thinking (i.e., affective states) with an individual's proclivity for developing an addiction. Data analysis demonstrates that psychological profiles of drug users and non-users have significant differences and the psychological predisposition to using different drugs may be different. Models of addiction risk that have been proposed in psychology literature include: an affect dysregulation model of positive and negative psychological affects, the reinforcement sensitivity theory of impulsiveness and behavioral inhibition, and an impulsivity model of reward sensitization and impulsiveness.
=== Neuropsychology ===
The transtheoretical model of change (TTM) can point to how someone may be conceptualizing their addiction and the thoughts around it, including not being aware of their addiction.
Cognitive control and stimulus control, which is associated with operant and classical conditioning, represent opposite processes (i.e., internal vs external or environmental, respectively) that compete over the control of an individual's elicited behaviors. Cognitive control, and particularly inhibitory control over behavior, is impaired in both addiction and attention deficit hyperactivity disorder. Stimulus-driven behavioral responses (i.e., stimulus control) that are associated with a particular rewarding stimulus tend to dominate one's behavior in an addiction.
==== Stimulus control of behavior ====
In operant conditioning, behavior is influenced by outside stimulus, such as a drug. The operant conditioning theory of learning is useful in understanding why the mood-altering or stimulating consequences of drug use can reinforce continued use (an example of positive reinforcement) and why the addicted person seeks to avoid withdrawal through continued use (an example of negative reinforcement). Stimulus control is using the absence of the stimulus or presence of a reward to influence the resulting behavior.
==== Cognitive control of behavior ====
Cognitive control is the intentional selection of thoughts, behaviors, and emotions, based on our environment. It has been shown that drugs alter the way our brains function, and its structure. Cognitive functions such as learning, memory, and impulse control, are affected by drugs. These effects promote drug use, as well as hinder the ability to abstain from it. The increase in dopamine release is prominent in drug use, specifically in the ventral striatum and the nucleus accumbens. Dopamine is responsible for producing pleasurable feelings, as well driving us to perform important life activities. Addictive drugs cause a significant increase in this reward system, causing a large increase in dopamine signaling as well as increase in reward-seeking behavior, in turn motivating drug use. This promotes the development of a maladaptive drug to stimulus relationship. Early drug use leads to these maladaptive associations, later affecting cognitive processes used for coping, which are needed to successfully abstain from them.
== Risk factors ==
A number of genetic and environmental risk factors exist for developing an addiction. Genetic and environmental risk factors each account for roughly half of an individual's risk for developing an addiction; the contribution from epigenetic risk factors to the total risk is unknown. Even in individuals with a relatively low genetic risk, exposure to sufficiently high doses of an addictive drug for a long period of time (e.g., weeks–months) can result in an addiction. Adverse childhood events are associated with negative health outcomes, such as substance use disorder. Childhood abuse or exposure to violent crime is related to developing a mood or anxiety disorder, as well as a substance dependence risk.
=== Genetic factors ===
Genetic factors, along with socio-environmental (e.g., psychosocial) factors, have been established as significant contributors to addiction vulnerability. Studies done on 350 hospitalized drug-dependent patients showed that over half met the criteria for alcohol abuse, with a role of familial factors being prevalent. Genetic factors account for 40–60% of the risk factors for alcoholism. Similar rates of heritability for other types of drug addiction have been indicated, specifically in genes that encode the Alpha5 Nicotinic Acetylcholine Receptor. Knestler hypothesized in 1964 that a gene or group of genes might contribute to predisposition to addiction in several ways. For example, altered levels of a normal protein due to environmental factors may change the structure or functioning of specific brain neurons during development. These altered brain neurons could affect the susceptibility of an individual to an initial drug use experience. In support of this hypothesis, animal studies have shown that environmental factors such as stress can affect an animal's genetic expression.
In humans, twin studies into addiction have provided some of the highest-quality evidence of this link, with results finding that if one twin is affected by addiction, the other twin is likely to be as well, and to the same substance. Further evidence of a genetic component is research findings from family studies which suggest that if one family member has a history of addiction, the chances of a relative or close family developing those same habits are much higher than one who has not been introduced to addiction at a young age.
The data implicating specific genes in the development of drug addiction is mixed for most genes. Many addiction studies that aim to identify specific genes focus on common variants with an allele frequency of greater than 5% in the general population. When associated with disease, these only confer a small amount of additional risk with an odds ratio of 1.1–1.3 percent; this has led to the development the rare variant hypothesis, which states that genes with low frequencies in the population (<1%) confer much greater additional risk in the development of the disease.
Genome-wide association studies (GWAS) are used to examine genetic associations with dependence, addiction, and drug use. These studies rarely identify genes from proteins previously described via animal knockout models and candidate gene analysis. Instead, large percentages of genes involved in processes such as cell adhesion are commonly identified. The important effects of endophenotypes are typically not capable of being captured by these methods. Genes identified in GWAS for drug addiction may be involved either in adjusting brain behavior before drug experiences, subsequent to them, or both.
=== Environmental factors ===
Environmental risk factors for addiction are the experiences of an individual during their lifetime that interact with the individual's genetic composition to increase or decrease his or her vulnerability to addiction. For example, after the nationwide outbreak of COVID-19, more people quit (vs. started) smoking; and smokers, on average, reduced the quantity of cigarettes they consumed. More generally, a number of different environmental factors have been implicated as risk factors for addiction, including various psychosocial stressors. The National Institute on Drug Abuse (NIDA) and studies cite lack of parental supervision, the prevalence of peer substance use, substance availability, and poverty as risk factors for substance use among children and adolescents. The brain disease model of addiction posits that an individual's exposure to an addictive drug is the most significant environmental risk factor for addiction. Many researchers, including neuroscientists, indicate that the brain disease model presents a misleading, incomplete, and potentially detrimental explanation of addiction.
The psychoanalytic theory model defines addiction as a form of defense against feelings of hopelessness and helplessness as well as a symptom of failure to regulate powerful emotions related to adverse childhood experiences (ACEs), various forms of maltreatment and dysfunction experienced in childhood. In this case, the addictive substance provides brief but total relief and positive feelings of control. The Adverse Childhood Experiences Study by the Centers for Disease Control and Prevention has shown a strong dose–response relationship between ACEs and numerous health, social, and behavioral problems throughout a person's lifespan, including substance use disorder. Children's neurological development can be permanently disrupted when they are chronically exposed to stressful events such as physical, emotional, or sexual abuse, physical or emotional neglect, witnessing violence in the household, or a parent being incarcerated or having a mental illness. As a result, the child's cognitive functioning or ability to cope with negative or disruptive emotions may be impaired. Over time, the child may adopt substance use as a coping mechanism or as a result of reduced impulse control, particularly during adolescence. Vast amounts of children who experienced abuse have gone on to have some form of addiction in their adolescence or adult life. This pathway towards addiction that is opened through stressful experiences during childhood can be avoided by a change in environmental factors throughout an individual's life and opportunities of professional help. If one has friends or peers who engage in drug use favorably, the chances of them developing an addiction increases. Family conflict and home management is a cause for one to become engaged in drug use.
==== Social control theory ====
According to Travis Hirschi's social control theory, adolescents with stronger attachments to family, religious, academic, and other social institutions are less likely to engage in delinquent and maladaptive behavior such as drug use leading to addiction.
=== Age ===
Adolescence represents a period of increased vulnerability for developing an addiction. In adolescence, the incentive-rewards systems in the brain mature well before the cognitive control center. This consequentially grants the incentive-rewards systems a disproportionate amount of power in the behavioral decision-making process. Therefore, adolescents are increasingly likely to act on their impulses and engage in risky, potentially addicting behavior before considering the consequences. Not only are adolescents more likely to initiate and maintain drug use, but once addicted they are more resistant to treatment and more liable to relapse.
Most individuals are exposed to and use addictive drugs for the first time during their teenage years. In the United States, there were just over 2.8 million new users of illicit drugs in 2013 (7,800 new users per day); among them, 54.1% were under 18 years of age. In 2011, there were approximately 20.6 million people in the United States over the age of 12 with an addiction. Over 90% of those with an addiction began drinking, smoking or using illicit drugs before the age of 18.
=== Comorbid disorders ===
Individuals with comorbid (i.e., co-occurring) mental health disorders such as depression, anxiety, attention-deficit/hyperactivity disorder (ADHD) or post-traumatic stress disorder are more likely to develop substance use disorders. The NIDA cites early aggressive behavior as a risk factor for substance use. The National Bureau of Economic Research found that there is a "definite connection between mental illness and the use of addictive substances" and a majority of mental health patients participate in the use of these substances: 38% alcohol, 44% cocaine, and 40% cigarettes.
=== Epigenetic ===
Epigenetics is the study of stable phenotypic changes that do not involve alterations in the DNA sequence. Illicit drug use has been found to cause epigenetic changes in DNA methylation, as well as chromatin remodeling. The epigenetic state of chromatin may pose as a risk for the development of substance addictions. It has been found that emotional stressors, as well as social adversities may lead to an initial epigenetic response, which causes an alteration to the reward-signalling pathways. This change may predispose one to experience a positive response to drug use.
==== Transgenerational epigenetic inheritance ====
Epigenetic genes and their products (e.g., proteins) are the key components through which environmental influences can affect the genes of an individual: they serve as the mechanism responsible for transgenerational epigenetic inheritance, a phenomenon in which environmental influences on the genes of a parent can affect the associated traits and behavioral phenotypes of their offspring (e.g., behavioral responses to environmental stimuli). In addiction, epigenetic mechanisms play a central role in the pathophysiology of the disease; it has been noted that some of the alterations to the epigenome which arise through chronic exposure to addictive stimuli during an addiction can be transmitted across generations, in turn affecting the behavior of one's children (e.g., the child's behavioral responses to addictive drugs and natural rewards).
The general classes of epigenetic alterations that have been implicated in transgenerational epigenetic inheritance include DNA methylation, histone modifications, and downregulation or upregulation of microRNAs. With respect to addiction, more research is needed to determine the specific heritable epigenetic alterations that arise from various forms of addiction in humans and the corresponding behavioral phenotypes from these epigenetic alterations that occur in human offspring. Based on preclinical evidence from animal research, certain addiction-induced epigenetic alterations in rats can be transmitted from parent to offspring and produce behavioral phenotypes that decrease the offspring's risk of developing an addiction. More generally, the heritable behavioral phenotypes that are derived from addiction-induced epigenetic alterations and transmitted from parent to offspring may serve to either increase or decrease the offspring's risk of developing an addiction.
== Mechanisms ==
Addiction is a disorder of the brain's reward system developing through transcriptional and epigenetic mechanisms as a result of chronically high levels of exposure to an addictive stimulus (e.g., eating food, the use of cocaine, engagement in sexual activity, participation in high-thrill cultural activities such as gambling, etc.) over extended time. DeltaFosB (ΔFosB), a gene transcription factor, is a critical component and common factor in the development of virtually all forms of behavioral and drug addictions. Two decades of research into ΔFosB's role in addiction have demonstrated that addiction arises, and the associated compulsive behavior intensifies or attenuates, along with the overexpression of ΔFosB in the D1-type medium spiny neurons of the nucleus accumbens. Due to the causal relationship between ΔFosB expression and addictions, it is used preclinically as an addiction biomarker. ΔFosB expression in these neurons directly and positively regulates drug self-administration and reward sensitization through positive reinforcement, while decreasing sensitivity to aversion.
Chronic addictive drug use causes alterations in gene expression in the mesocorticolimbic projection. The most important transcription factors that produce these alterations are ΔFosB, cAMP response element binding protein (CREB), and nuclear factor kappa B (NF-κB). ΔFosB is the most significant biomolecular mechanism in addiction because the overexpression of ΔFosB in the D1-type medium spiny neurons in the nucleus accumbens is necessary and sufficient for many of the neural adaptations and behavioral effects (e.g., expression-dependent increases in drug self-administration and reward sensitization) seen in drug addiction. ΔFosB expression in nucleus accumbens D1-type medium spiny neurons directly and positively regulates drug self-administration and reward sensitization through positive reinforcement while decreasing sensitivity to aversion. ΔFosB has been implicated in mediating addictions to many different drugs and drug classes, including alcohol, amphetamine and other substituted amphetamines, cannabinoids, cocaine, methylphenidate, nicotine, opiates, phenylcyclidine, and propofol, among others. ΔJunD, a transcription factor, and G9a, a histone methyltransferase, both oppose the function of ΔFosB and inhibit increases in its expression. Increases in nucleus accumbens ΔJunD expression (via viral vector-mediated gene transfer) or G9a expression (via pharmacological means) reduces, or with a large increase can even block, many of the neural and behavioral alterations that result from chronic high-dose use of addictive drugs (i.e., the alterations mediated by ΔFosB).
ΔFosB plays an important role in regulating behavioral responses to natural rewards, such as palatable food, sex, and exercise. Natural rewards, like drugs of abuse, induce gene expression of ΔFosB in the nucleus accumbens, and chronic acquisition of these rewards can result in a similar pathological addictive state through ΔFosB overexpression. Consequently, ΔFosB is the key transcription factor involved in addictions to natural rewards (i.e., behavioral addictions) as well; in particular, ΔFosB in the nucleus accumbens is critical for the reinforcing effects of sexual reward. Research on the interaction between natural and drug rewards suggests that dopaminergic psychostimulants (e.g., amphetamine) and sexual behavior act on similar biomolecular mechanisms to induce ΔFosB in the nucleus accumbens and possess bidirectional cross-sensitization effects that are mediated through ΔFosB. This phenomenon is notable since, in humans, a dopamine dysregulation syndrome, characterized by drug-induced compulsive engagement in natural rewards (specifically, sexual activity, shopping, and gambling), has been observed in some individuals taking dopaminergic medications.
ΔFosB inhibitors (drugs or treatments that oppose its action) may be an effective treatment for addiction and addictive disorders.
The release of dopamine in the nucleus accumbens plays a role in the reinforcing qualities of many forms of stimuli, including naturally reinforcing stimuli like palatable food and sex. Altered dopamine neurotransmission is frequently observed following the development of an addictive state. In humans and lab animals that have developed an addiction, alterations in dopamine or opioid neurotransmission in the nucleus accumbens and other parts of the striatum are evident. Use of certain drugs (e.g., cocaine) affect cholinergic neurons that innervate the reward system, in turn affecting dopamine signaling in this region.
A recent study in Addiction reports that GLP-1 agonist medications, such as semaglutide, which are commonly used for diabetes and weight management, may also reduce the risk of overdose and alcohol intoxication in people with substance use disorders. The study analyzed nearly nine years of health records from 1.3 million individuals across 136 U.S. hospitals, including 500,000 with opioid use disorder and over 800,000 with alcohol use disorder. Researchers found that those who used Ozempic or similar medications had a 40% lower risk of opioid overdose and a 50% lower risk of alcohol intoxication compared to those not using these drugs.
=== Reward system ===
==== Mesocorticolimbic pathway ====
Understanding the pathways in which drugs act and how drugs can alter those pathways is key when examining the biological basis of drug addiction. The reward pathway, known as the mesolimbic pathway, or its extension, the mesocorticolimbic pathway, is characterized by the interaction of several areas of the brain.
The projections from the ventral tegmental area (VTA) are a network of dopaminergic neurons with co-localized postsynaptic glutamate receptors (AMPAR and NMDAR). These cells respond when stimuli indicative of a reward are present. The VTA supports learning and sensitization development and releases dopamine (DA) into the forebrain. These neurons project and release DA into the nucleus accumbens, through the mesolimbic pathway. Virtually all drugs causing drug addiction increase the DA release in the mesolimbic pathway.
The nucleus accumbens (NAcc) is one output of the VTA projections. The nucleus accumbens itself consists mainly of GABAergic medium spiny neurons (MSNs). The NAcc is associated with acquiring and eliciting conditioned behaviors, and is involved in the increased sensitivity to drugs as addiction progresses. Overexpression of ΔFosB in the nucleus accumbens is a necessary common factor in essentially all known forms of addiction; ΔFosB is a strong positive modulator of positively reinforced behaviors.
The prefrontal cortex, including the anterior cingulate and orbitofrontal cortices, is another VTA output in the mesocorticolimbic pathway; it is important for the integration of information which helps determine whether a behavior will be elicited. It is critical for forming associations between the rewarding experience of drug use and cues in the environment. Importantly, these cues are strong mediators of drug-seeking behavior and can trigger relapse even after months or years of abstinence.
Other brain structures that are involved in addiction include:
The basolateral amygdala projects into the NAcc and is thought to be important for motivation.
The hippocampus is involved in drug addiction, because of its role in learning and memory. Much of this evidence stems from investigations showing that manipulating cells in the hippocampus alters DA levels in NAcc and firing rates of VTA dopaminergic cells.
==== Role of dopamine and glutamate ====
Dopamine is the primary neurotransmitter of the reward system in the brain. It plays a role in regulating movement, emotion, cognition, motivation, and feelings of pleasure. Natural rewards, like eating, as well as recreational drug use cause a release of dopamine, and are associated with the reinforcing nature of these stimuli. Nearly all addictive drugs, directly or indirectly, act on the brain's reward system by heightening dopaminergic activity.
Excessive intake of many types of addictive drugs results in repeated release of high amounts of dopamine, which in turn affects the reward pathway directly through heightened dopamine receptor activation. Prolonged and abnormally high levels of dopamine in the synaptic cleft can induce receptor downregulation in the neural pathway. Downregulation of mesolimbic dopamine receptors can result in a decrease in the sensitivity to natural reinforcers.
Drug seeking behavior is induced by glutamatergic projections from the prefrontal cortex to the nucleus accumbens. This idea is supported with data from experiments showing that drug seeking behavior can be prevented following the inhibition of AMPA glutamate receptors and glutamate release in the nucleus accumbens.
=== Reward sensitization ===
Reward sensitization is a process that causes an increase in the amount of reward (specifically, incentive salience) that is assigned by the brain to a rewarding stimulus (e.g., a drug). In simple terms, when reward sensitization to a specific stimulus (e.g., a drug) occurs, an individual's "wanting" or desire for the stimulus itself and its associated cues increases. Reward sensitization normally occurs following chronically high levels of exposure to the stimulus. ΔFosB expression in D1-type medium spiny neurons in the nucleus accumbens has been shown to directly and positively regulate reward sensitization involving drugs and natural rewards.
"Cue-induced wanting" or "cue-triggered wanting", a form of craving that occurs in addiction, is responsible for most of the compulsive behavior that people with addictions exhibit. During the development of an addiction, the repeated association of otherwise neutral and even non-rewarding stimuli with drug consumption triggers an associative learning process that causes these previously neutral stimuli to act as conditioned positive reinforcers of addictive drug use (i.e., these stimuli start to function as drug cues). As conditioned positive reinforcers of drug use, these previously neutral stimuli are assigned incentive salience (which manifests as a craving) – sometimes at pathologically high levels due to reward sensitization – which can transfer to the primary reinforcer (e.g., the use of an addictive drug) with which it was originally paired.
Research on the interaction between natural and drug rewards suggests that dopaminergic psychostimulants (e.g., amphetamine) and sexual behavior act on similar biomolecular mechanisms to induce ΔFosB in the nucleus accumbens and possess a bidirectional reward cross-sensitization effect that is mediated through ΔFosB. In contrast to ΔFosB's reward-sensitizing effect, CREB transcriptional activity decreases user's sensitivity to the rewarding effects of the substance. CREB transcription in the nucleus accumbens is implicated in psychological dependence and symptoms involving a lack of pleasure or motivation during drug withdrawal.
=== Neuroepigenetic mechanisms ===
Altered epigenetic regulation of gene expression within the brain's reward system plays a significant and complex role in the development of drug addiction. Addictive drugs are associated with three types of epigenetic modifications within neurons. These are (1) histone modifications, (2) epigenetic methylation of DNA at CpG sites at (or adjacent to) particular genes, and (3) epigenetic downregulation or upregulation of microRNAs which have particular target genes. As an example, while hundreds of genes in the cells of the nucleus accumbens (NAc) exhibit histone modifications following drug exposure – particularly, altered acetylation and methylation states of histone residues – most other genes in the NAc cells do not show such changes.
== Diagnosis ==
=== Classification ===
==== DSM-5 ====
The fifth edition of the DSM uses the term substance use disorder to refer to a spectrum of drug use-related disorders. The DSM-5 eliminates the terms abuse and dependence from diagnostic categories, instead using the specifiers of mild, moderate and severe to indicate the extent of disordered use. These specifiers are determined by the number of diagnostic criteria present in a given case. In the DSM-5, the term drug addiction is synonymous with severe substance use disorder.
The DSM-5 introduced a new diagnostic category for behavioral addictions. Problem gambling is the only condition included in this category in the fifth edition. Internet gaming disorder is listed as a "condition requiring further study" in the DSM-5.
Past editions have used physical dependence and the associated withdrawal syndrome to identify an addictive state. Physical dependence occurs when the body has adjusted by incorporating the substance into its "normal" functioning – i.e., attains homeostasis – and therefore physical withdrawal symptoms occur on cessation of use. Tolerance is the process by which the body continually adapts to the substance and requires increasingly larger amounts to achieve the original effects. Withdrawal refers to physical and psychological symptoms experienced when reducing or discontinuing a substance that the body has become dependent on. Symptoms of withdrawal generally include but are not limited to body aches, anxiety, irritability, intense cravings for the substance, dysphoria, nausea, hallucinations, headaches, cold sweats, tremors, and seizures. During acute physical opioid withdrawal, symptoms of restless legs syndrome are common and may be profound. This phenomenon originated the idiom "kicking the habit".
Medical researchers who actively study addiction have criticized the DSM classification of addiction for being flawed and involving arbitrary diagnostic criteria.
==== ICD-11 ====
The eleventh revision of the International Classification of Diseases, commonly referred to as ICD-11, conceptualizes diagnosis somewhat differently. ICD-11 first distinguishes between problems with psychoactive substance use ("Disorders due to substance use") and behavioral addictions ("Disorders due to addictive behaviours"). With regard to psychoactive substances, ICD-11 explains that the included substances initially produce "pleasant or appealing psychoactive effects that are rewarding and reinforcing with repeated use, [but] with continued use, many of the included substances have the capacity to produce dependence. They have the potential to cause numerous forms of harm, both to mental and physical health." Instead of the DSM-5 approach of one diagnosis ("Substance Use Disorder") covering all types of problematic substance use, ICD-11 offers three diagnostic possibilities: 1) Episode of Harmful Psychoactive Substance Use, 2) Harmful Pattern of Psychoactive Substance Use, and 3) Substance Dependence.
=== Screening and assessment ===
==== Addictions Neuroclinical Assessment ====
The Addictions Neuroclinical Assessment is used to diagnose addiction disorders. This tool measures three different domains: executive function, incentive salience, and negative emotionality. Executive functioning consists of processes that would be disrupted in addiction. In the context of addiction, incentive salience determines how one perceives the addictive substance. Increased negative emotional responses have been found with individuals with addictions.
==== Tobacco, Alcohol, Prescription Medication, and Other Substance Use (TAPS) ====
This is a screening and assessment tool in one, assessing commonly used substances. This tool allows for a simple diagnosis, eliminating the need for several screening and assessment tools, as it includes both TAPS-1 and TAPS-2, screening and assessment tools respectively. The screening component asks about the frequency of use of the specific substance (tobacco, alcohol, prescription medication, and other). If an individual screens positive, the second component will begin. This dictates the risk level of the substance.
==== CRAFFT ====
The CRAFFT (Car-Relax-Alone-Forget-Family and Friends-Trouble) is a screening tool that is used in medical centers. The CRAFFT is in version 2.1 and has a version for nicotine and tobacco use called the CRAFFT 2.1+N. This tool is used to identify substance use, substance related driving risk, and addictions among adolescents. This tool uses a set of questions for different scenarios. In the case of a specific combination of answers, different question sets can be used to yield a more accurate answer. After the questions, the DSM-5 criteria are used to identify the likelihood of the person having substance use disorder. After these tests are done, the clinician is to give the "5 RS" of brief counseling.
The five Rs of brief counseling includes:
REVIEW screening results
RECOMMEND to not use
RIDING/DRIVING risk counseling
RESPONSE: elicit self-motivational statements
REINFORCE self-efficacy
==== Drug Abuse Screening Test (DAST-10) ====
The Drug Abuse Screening Test (DAST) is a self-reporting tool that measures problematic substance use. Responses to this test are recorded as yes or no answers, and scored as a number between zero and 28. Drug abuse or dependence, are indicated by a cut off score of 6. Three versions of this screening tool are in use: DAST-28, DAST-20, and DAST-10. Each of these instruments are copyrighted by Dr. Harvey A. Skinner.
==== Alcohol, Smoking, and Substance Involvement Test (ASSIST) ====
The Alcohol, Smoking, and Substance Involvement Test (ASSIST) is an interview-based questionnaire consisting of eight questions developed by the WHO. The questions ask about lifetime use; frequency of use; urge to use; frequency of health, financial, social, or legal problems related to use; failure to perform duties; if anyone has raised concerns over use; attempts to limit or moderate use; and use by injection.
== Prevention ==
=== Abuse liability ===
Abuse or addiction liability is the tendency to use drugs in a non-medical situation. This is typically for euphoria, mood changing, or sedation. Abuse liability is used when the person using the drugs wants something that they otherwise can not obtain. The only way to obtain this is through the use of drugs. When looking at abuse liability there are a number of determining factors in whether the drug is abused. These factors are: the chemical makeup of the drug, the effects on the brain, and the age, vulnerability, and the health (mental and physical) of the population being studied. There are a few drugs with a specific chemical makeup that leads to a high abuse liability. These are: cocaine, heroin, inhalants, marijuana, MDMA (ecstasy), methamphetamine, PCP, synthetic cannabinoids, synthetic cathinones (bath salts), nicotine (e.g. tobacco), and alcohol.
=== Potential vaccines for addiction to substances ===
Vaccines for addiction have been investigated as a possibility since the early 2000s. The general theory of a vaccine intended to "immunize" against drug addiction or other substance abuse is that it would condition the immune system to attack and consume or otherwise disable the molecules of such substances that cause a reaction in the brain, thus preventing the addict from being able to realize the effect of the drug. Addictions that have been floated as targets for such treatment include nicotine, opioids, and fentanyl. Vaccines have been identified as potentially being more effective than other anti-addiction treatments, due to "the long duration of action, the certainty of administration and a potential reduction of toxicity to important organs".
Specific addiction vaccines in development include:
NicVAX, a conjugate vaccine intended to reduce or eliminate physical dependence on nicotine. This proprietary vaccine is being developed by Nabi Biopharmaceuticals of Rockville, MD. with the support from the U.S. National Institute on Drug Abuse. NicVAX consists of the hapten 3'-aminomethylnicotine which has been conjugated (attached) to Pseudomonas aeruginosa exotoxin A.
TA-CD, an active vaccine developed by the Xenova Group which is used to negate the effects of cocaine. It is created by combining norcocaine with inactivated cholera toxin. It works in much the same way as a regular vaccine. A large protein molecule attaches to cocaine, which stimulates response from antibodies, which destroy the molecule. This also prevents the cocaine from crossing the blood–brain barrier, negating the euphoric high and rewarding effect of cocaine caused from stimulation of dopamine release in the mesolimbic reward pathway. The vaccine does not affect the user's "desire" for cocaine—only the physical effects of the drug.
TA-NIC, used to create human antibodies to destroy nicotine in the human body so that it is no longer effective.
As of September 2023, it was further reported that a vaccine "has been tested against heroin and fentanyl and is on its way to being tested against OxyContin".
== Treatment ==
To be effective, treatment for addiction that is pharmacological or biologically based need to be accompanied by other interventions such as cognitive behavioral therapy (CBT) and dialectical behavioral therapy (DBT); individual and group psychotherapy, behavior modification strategies, twelve-step programs, and residential treatment facilities. The transtheoretical model (TTM) can be used to determine when treatment can begin and which method will be most effective. If treatment begins too early, it can cause a person to become defensive and resistant to change.
== Epidemiology ==
Due to cultural variations, the proportion of individuals who develop a drug or behavioral addiction within a specified time period (i.e., the prevalence) varies over time, by country, and across national population demographics (e.g., by age group, socioeconomic status, etc.). Where addiction is viewed as unacceptable, there will be fewer people addicted.
=== Asia ===
The prevalence of alcohol dependence is not as high as is seen in other regions. In Asia, not only socioeconomic factors but biological factors influence drinking behavior.
Internet addiction disorder is highest in the Philippines, according to both the IAT (Internet Addiction Test) – 5% and the CIAS-R (Revised Chen Internet Addiction Scale) – 21%.
=== Australia ===
The prevalence of substance use disorder among Australians was reported at 5.1% in 2009. In 2019 the Australian Institute of Health and Welfare conducted a national drug survey that quantified drug use for various types of drugs and demographics. The survey found that in 2019, 11% of people over 14 years old smoke daily; that 9.9% of those who drink alcohol, which equates to 7.5% of the total population age 14 or older, may qualify as alcohol dependent; that 17.5% of the 2.4 million people who used cannabis in the last year may have hazardous use or a dependence problem; and that 63.5% of about 300000 recent users of meth and amphetamines were at risk for developing problem use.
=== Europe ===
In 2015, the estimated prevalence among the adult population was 18.4% for heavy episodic alcohol use (in the past 30 days); 15.2% for daily tobacco smoking; and 3.8% for cannabis use, 0.77% for amphetamine use, 0.37% for opioid use, and 0.35% for cocaine use in 2017. The mortality rates for alcohol and illicit drugs were highest in Eastern Europe. Data shows a downward trend of alcohol use among children 15 years old in most European countries between 2002 and 2014. First-time alcohol use before the age of 13 was recorded for 28% of European children in 2014.
=== United States ===
Based on representative samples of the US youth population in 2011, the lifetime prevalence of addictions to alcohol and illicit drugs has been estimated to be approximately 8% and 2–3% respectively. Based on representative samples of the US adult population in 2011, the 12-month prevalence of alcohol and illicit drug addictions were estimated at 12% and 2–3% respectively. The lifetime prevalence of prescription drug addictions is around 4.7%.
As of 2021, 43.7 million people aged 12 or older surveyed by the National Survey on Drug Use and Health in the United States needed treatment for an addiction to alcohol, nicotine, or other drugs. The groups with the highest number of people were 18–25 years (25.1%) and "American Indian or Alaska Native" (28.7%). Only about 10%, or a little over 2 million, receive any form of treatments, and those that do generally do not receive evidence-based care. One-third of inpatient hospital costs and 20% of all deaths in the US every year are the result of untreated addictions and risky substance use. In spite of the massive overall economic cost to society, which is greater than the cost of diabetes and all forms of cancer combined, most doctors in the US lack the training to effectively address a drug addiction.
Estimates of lifetime prevalence rates in the US are 1–2% for compulsive gambling, 5% for sexual addiction, 2.8% for food addiction, and 5–6% for compulsive shopping. The time-invariant prevalence rate for sexual addiction and related compulsive sexual behavior (e.g., compulsive masturbation with or without pornography, compulsive cybersex, etc.) within the US ranges from 3–6% of the population.
According to a 2017 poll conducted by the Pew Research Center, almost half of US adults know a family member or close friend who has struggled with a drug addiction at some point in their life.
In 2019, opioid addiction was acknowledged as a national crisis in the United States. An article in The Washington Post stated that "America's largest drug companies flooded the country with pain pills from 2006 through 2012, even when it became apparent that they were fueling addiction and overdoses."
The National Epidemiologic Survey on Alcohol and Related Conditions found that from 2012 to 2013 the prevalence of Cannabis use disorder in U.S. adults was 2.9%.
=== Canada ===
A Statistics Canada Survey in 2012 found the lifetime prevalence and 12-month prevalence of substance use disorders were 21.6%, and 4.4% in those 15 and older. Alcohol abuse or dependence reported a lifetime prevalence of 18.1% and a 12-month prevalence of 3.2%. Cannabis abuse or dependence reported a lifetime prevalence of 6.8% and a 12-month prevalence of 3.2%. Other drug abuse or dependence has a lifetime prevalence of 4.0% and a 12-month prevalence of 0.7%. Substance use disorder is a term used interchangeably with a drug addiction.
In Ontario, Canada between 2009 and 2017, outpatient visits for mental health and addiction increased from 52.6 to 57.2 per 100 people, emergency department visits increased from 13.5 to 19.7 per 1000 people and the number of hospitalizations increased from 4.5 to 5.5 per 1000 people. Prevalence of care needed increased the most among the 14–17 age group overall.
=== South America ===
The realities of opioid use and opioid use disorder in Latin America may be deceptive if observations are limited to epidemiological findings. In the United Nations Office on Drugs and Crime report, although South America produced 3% of the world's morphine and heroin and 0.01% of its opium, prevalence of use is uneven. According to the Inter-American Commission on Drug Abuse Control, consumption of heroin is low in most Latin American countries, although Colombia is the area's largest opium producer. Mexico, because of its border with the United States, has the highest incidence of use.
== Etymology ==
The word addiction derives from the Latin "addico", meaning "giving over" with both positive connotations (devotion, dedication) and negative ones (being enslaved to a creditor in Roman law). This dual meaning persisted in traditional English dictionaries, encompassing both legal surrender and personal devotion to habits. Later, 19th century temperance movements narrowed the definition of addiction to just drug-related disease, ignoring behavioral addictions and the possibility of positive or neutral addictions. This restrictive view opposes the current understanding of addiction.
Addiction and addictive behavior are polysemes denoting a category of mental disorders, of neuropsychological symptoms, or of merely maladaptive/harmful habits and lifestyles. A common use of the term addiction in medicine is for neuropsychological symptoms denoting pervasive/excessive and intense urges to engage in a category of behavioral compulsions or impulses towards sensory rewards (e.g., alcohol, betel quid, drugs, sex, gambling, video gaming). Addictive disorders or addiction disorders are mental disorders involving high intensities of addictions (as neuropsychological symptoms) that induce functional disabilities (i.e., limit subjects' social/family and occupational activities); the two categories of such disorders are substance-use addictions and behavioral addictions.
The etymology of the term addiction throughout history has been misunderstood and has taken on various meanings associated with the word. An example is the usage of the word in the religious landscape of early modern Europe. "Addiction" at the time meant "to attach" to something, giving it both positive and negative connotations. The object of this attachment could be characterized as "good or bad". The meaning of addiction during the early modern period was mostly associated with positivity and goodness; during this early modern and highly religious era of Christian revivalism and Pietistic tendencies, it was seen as a way of "devoting oneself to another".
=== The suffixes "-holic" and "-holism" ===
In contemporary modern English "-holic" is a suffix that can be added to a subject to denote an addiction to it. It was extracted from the word alcoholism (one of the first addictions to be widely identified both medically and socially) (correctly the root "alcohol" plus the suffix "-ism") by misdividing or rebracketing it into "alco" and "-holism". There are correct medico-legal terms for such addictions: dipsomania is the medico-legal term for alcoholism; other examples are in this table:
== History ==
Modern research on addiction has led to a better understanding of the disease with research on the topic dating back to 1875, specifically on morphine addiction. This furthered the understanding of addiction being a medical condition. It was not until the 19th century that addiction was seen and acknowledged in the Western world as a disease, being both a physical condition and mental illness. Today, addiction is understood both as a biopsychosocial and neurological disorder that negatively impacts those who are affected by it, most commonly associated with the use of drugs and excessive use of alcohol. The understanding of addiction has changed throughout history, which has impacted and continues to impact the ways it is medically treated and diagnosed.
== Addiction and art ==
The arts can be used in a variety of ways to address issues related to addiction. Art can be used as a form of therapy in the treatment of substance use disorders. Creative activities like painting, sculpting, music, and writing can help people express their feelings and experiences in safe and healthy ways. The arts can be used as an assessment tool to identify underlying issues that may be contributing to a person's substance use disorder. Through art, individuals can gain insights into their own motivations and behaviors that can be helpful in determining a course of treatment. Finally, the arts can be used to advocate for those suffering from a substance use disorder by raising awareness of the issue and promoting understanding and compassion. Through art, individuals can share their stories, increase awareness, and offer support and hope to those struggling with substance use disorders.
=== As therapy ===
Addiction treatment is complex and not always effective due to engagement and service availability concerns, so researchers prioritize efforts to improve treatment retention and decrease relapse rates. Characteristics of substance abuse may include feelings of isolation, a lack of confidence, communication difficulties, and a perceived lack of control. In a similar vein, people suffering from substance use disorders tend to be highly sensitive, creative, and as such, are likely able to express themselves meaningfully in creative arts such as dancing, painting, writing, music, and acting. Further evidenced by Waller and Mahony (2002) and Kaufman (1981), the creative arts therapies can be a suitable treatment option for this population especially when verbal communication is ineffective.
Primary advantages of art therapy in the treatment of addiction have been identified as:
Assess and characterize a client's substance use issues
Bypassing a client's resistances, defenses, and denial
Containing shame or anger
Facilitating the expression of suppressed and/or complicated emotions
Highlighting a client's strengths
Providing an alternative to verbal communication (via use of symbols) and conventional forms of therapy
Providing clients with a sense of control
Tackling feelings of isolation
Art therapy is an effective method of dealing with substance abuse in comprehensive treatment models. When included in psychoeducational programs, art therapy in a group setting can help clients internalize taught concepts in a more personalized manner. During the course of treatment, by examining and comparing artwork created at different times, art therapists can be helpful in identifying and diagnosing issues, as well as charting the extent or direction of improvement as a person detoxifies. Where increasing adherence to treatment regimes and maintaining abstinence is the target; art therapists can aid by customizing treatment directives (encourage the client to create collages that compare pros and cons, pictures that compare past and present and future, and drawings that depict what happened when a client went off medication).
Art therapy can function as a complementary therapy used in conjunction with more conventional therapies and can integrate with harm reduction protocols to minimize the negative effects of drug use. An evaluation of art therapy incorporation within a pre-existing Addiction Treatment Programme based on the 12 step Minnesota Model endorsed by the Alcoholics Anonymous found that 66% of participants expressed the usefulness of art therapy as a part of treatment. Within the weekly art therapy session, clients were able to reflect and process the intense emotions and cognitions evoked by the programme. In turn, the art therapy component of the programme fostered stronger self-awareness, exploration, and externalization of repressed and unconscious emotions of clients, promoting the development of a more integrated 'authentic self'.
Despite the large number of randomized control trials, clinical control trials, and anecdotal evidence supporting the effectiveness of art therapies for use in addiction treatment, a systematic review conducted in 2018 could not find enough evidence on visual art, drama, dance and movement therapy, or 'arts in health' methodologies to confirm their effectiveness as interventions for reducing substance misuse. Music therapy was identified to have potentially strong beneficial effects in aiding contemplation and preparing those diagnosed with substance use for treatment.
=== As an assessment tool ===
The Formal Elements Art Therapy Scale (FEATS) is an assessment tool used to evaluate drawings created by people suffering from substance use disorders by comparing them to drawings of a control group (consisting of individuals without SUDs). FEATS consists of twelve elements, three of which were found to be particularly effective at distinguishing the drawings of those with SUDs from those without: Person, Realism, and Developmental. The Person element assesses the degree to which a human features are depicted realistically, the Realism element assesses the overall complexity of the artwork, and the Developmental element assesses "developmental age" of the artwork in relation to standardized drawings from children and adolescents. By using the FEATS assessment tool, clinicians can gain valuable insight into the drawings of individuals with SUDs, and can compare them to those of the control group. Formal assessments such as FEATS provide healthcare providers with a means to quantify, standardize, and communicate abstract and visceral characteristics of SUDs to provide more accurate diagnoses and informed treatment decisions.
Other artistic assessment methods include the Bird's Nest Drawing: a useful tool for visualizing a client's attachment security. This assessment method looks at the amount of color used in the drawing, with a lack of color indicating an 'insecure attachment', a factor that the client's therapist or recovery framework must take into account.
Art therapists working with children of parents suffering from alcoholism can use the Kinetic Family Drawings assessment tool to shed light on family dynamics and help children express and understand their family experiences. The KFD can be used in family sessions to allow children to share their experiences and needs with parents who may be in recovery from alcohol use disorder. Depiction of isolation of self and isolation of other family members may be an indicator of parental alcoholism.
=== Advocacy ===
Stigma can lead to feelings of shame that can prevent people with substance use disorders from seeking help and interfere with provision of harm reduction services. It can influence healthcare policy, making it difficult for these individuals to access treatment.
Artists attempt to change the societal perception of addiction from a punishable moral offense to instead a chronic illness necessitating treatment. This form of advocacy can help to relocate the fight of addiction from a judicial perspective to the public health system.
Artists who have personally lived with addiction or undergone recovery may use art to depict their experiences in a manner that uncovers the "human face of addiction". By bringing experiences of addiction and recovery to a personal level and breaking down the "us and them", the viewer may be more inclined to show compassion, forego stereotypes and stigma of addiction, and label addiction as a social rather than individual problem.
According to Santora the main purposes in using art as a form of advocacy in the education and prevention of substance use disorders include:
Addiction art exhibitions can come from a variety of sources, but the underlying message of these works is the same: to communicate through emotions without relying on intellectually demanding/gatekept facts and figures. These exhibitions can either stand alone, reinforce, or challenge facts.
A powerful educational tool for increasing awareness and understanding of addiction as a medical illness. Exhibitions featuring personal stories and images can help to create lasting impressions on diverse audiences (including addiction scientists/researchers, family/friends of those affected by addiction etc.), highlighting the humanity of the problem and in turn encouraging compassion and understanding.
A way to destigmatize substance use disorders and shift public perception from viewing them as a moral failing to understanding them as a chronic medical condition which requires treatment.
Provide those who are struggling with addiction assurance and encouragement of healing, and let them know that they are not alone in their struggle.
The use of visual arts can help bring attention to the lack of adequate substance use treatment, prevention, and education programs and services in a healthcare system. Messages can encourage policymakers to allocate more resources to addiction treatment and prevention from federal, state, and local levels.
The Temple University College of Public Health department conducted a project to promote awareness around opioid use and reduce associated stigma by asking students to create art pieces that were displayed on a website they created and promoted via social media. Quantitative and qualitative data was recorded to measure engagement, and the student artists were interviewed, which revealed a change in perspective and understanding, as well as greater appreciation of diverse experiences. Ultimately, the project found that art was an effective medium for empowering both the artist creating the work and the person interacting with it.
Another author critically examined works by contemporary Canadian artists that deal with addiction via the metaphor of a cultural landscape to "unmap" and "remap" ideologies related to Indigenous communities and addiction to demonstrate how colonial violence in Canada has drastically impacted the relationship between Indigenous peoples, their land, and substance abuse.
A project known as "Voice" was a collection of art, poetry and narratives created by women living with a history of addiction to explore women's understanding of harm reduction, challenge the effects of stigma and give voice to those who have historically been silenced or devalued. In the project, nurses with knowledge of mainstream systems, aesthetic knowing, feminism and substance use organized weekly gatherings, wherein women with histories of substance use and addiction worked alongside a nurse to create artistic expressions. Creations were presented at several venues, including an International Conference on Drug Related Harm, a Nursing Conference and a local gallery to positive community response.
== Social scientific models ==
=== Biopsychosocial–cultural–spiritual ===
While regarded biomedically as a neuropsychological disorder, addiction is multi-layered, with biological, psychological, social, cultural, and spiritual (biopsychosocial–cultural–spiritual) elements. A biopsychosocial–cultural–spiritual approach fosters the crossing of disciplinary boundaries, and promotes holistic considerations of addiction. A biopsychosocial–cultural–spiritual approach considers, for example, how physical environments influence experiences, habits, and patterns of addiction.
Ethnographic engagements and developments in fields of knowledge have contributed to biopsychosocial–cultural–spiritual understandings of addiction, including the work of Philippe Bourgois, whose fieldwork with street-level drug dealers in East Harlem highlights correlations between drug use and structural oppression in the United States. Prior models that have informed the prevailing biopsychosocial–cultural–spiritual consideration of addiction include:
=== Cultural model ===
The cultural model, an anthropological understanding of the emergence of drug use and abuse, was developed by Dwight Heath. Heath undertook ethnographic research and fieldwork with the Camba people of Bolivia from June 1956 to August 1957. Heath observed that adult members of society drank 'large quantities of rum and became intoxicated for several contiguous days at least twice a month'. This frequent, heavy drinking from which intoxication followed was typically undertaken socially, during festivals. Having returned in 1989, Heath observed that while much had changed, 'drinking parties' remained, as per his initial observations, and 'there appear to be no harmful consequences to anyone'. Heath's observations and interactions reflected that this form of social behavior, the habitual heavy consumption of alcohol, was encouraged and valued, enforcing social bonds in the Camba community. Despite frequent intoxication, "even to the point of unconsciousness", the Camba held no concept of alcoholism (a form of addiction), and no visible social problems associated with drunkenness, or addiction, were apparent.
As noted by Merrill Singer, Heath's findings, when considered alongside subsequent cross-cultural experiences, challenged the perception that intoxication is socially 'inherently disruptive'. Following this fieldwork, Heath proposed the 'cultural model', suggesting that 'problems' associated with heavy drinking, such as alcoholism – a recognised form addiction – were cultural: that is, that alcoholism is determined by cultural beliefs, and therefore varies among cultures. Heath's findings challenged the notion that 'continued use [of alcohol] is inexorably addictive and damaging to the consumer's health'.
The cultural model did face criticism by Sociologist Robin Room and others, who felt anthropologists could "downgrade the severity of the problem". Merrill Singer found it notable that the ethnographers working within the prominence of the cultural model were part of the 'wet generation': while not blind to the 'disruptive, dysfunctional and debilitating effects of alcohol consumption', they were products 'socialized to view alcohol consumption as normal'.
=== Subcultural model ===
Historically, addiction has been viewed from the etic perspective, defining users through the pathology of their condition. As reports of drug use rapidly increased, the cultural model found application in anthropological research exploring western drug subculture practices.
The approach evolved from the ethnographic exploration into the lived experiences and subjectivities of 1960s and 1970s drug subcultures. The seminal publication "Taking care of business", by Edward Preble and John J. Casey, documented the daily lives of New York street-based intravenous heroin users in rich detail, providing unique insight into the dynamic social worlds and activities that surrounded their drug use. These findings challenge popular narratives of immorality and deviance, conceptualizing substance abuse as a social phenomenon. The prevailing culture can have a greater influence on drug taking behaviors than the physical and psychological effects of the drug itself. To marginalized individuals, drug subcultures can provide social connection, symbolic meaning, and socially constructed purpose that they may feel is unattainable through conventional means. The subcultural model demonstrates the complexities of addiction, highlighting the need for an integrated approach. It contends that a biosocial approach is required to achieve a holistic understanding of addiction.
=== Critical medical anthropology model ===
Emerging in the early 1980s, the critical medical anthropology model was introduced, and as Merrill Singer offers 'was applied quickly to the analysis of drug use'. Where the cultural model of the 1950s looked at the social body, the critical medical anthropology model revealed the body politic, considering drug use and addiction within the context of macro level structures including larger political systems, economic inequalities, and the institutional power held over social processes.
Highly relevant to addiction, the three issues emphasized in the model are:
Self-medication
The social production of suffering
The political economy (Licit and Illicit Drugs)
These three key points highlight how drugs may come to be used to self-medicate the psychological trauma of socio-political disparity and injustice, intertwining with licit and illicit drug market politics. Social suffering, "the misery among those on the weaker end of power relations in terms of physical health, mental health and lived experience", is used by anthropologists to analyze how individuals may have personal problems caused by political and economic power. From the perspective of critical medical anthropology heavy drug use and addiction is a consequence of such larger scale unequal distributions of power.
The three models developed here – the cultural model, the subcultural model, and the Critical Medical Anthropology Model – display how addiction is not an experience to be considered only biomedically. Through consideration of addiction alongside the biological, psychological, social, cultural and spiritual (biopsychosocial–spiritual) elements which influence its experience, a holistic and comprehensive understanding can be built.
== Social learning models ==
=== Social learning theory ===
Albert Bandura's 1977 social learning theory posits that individuals acquire addictive behaviors by observing and imitating models in their social environment. The likelihood of engaging in and sustaining similar addictive behaviors is influenced by the reinforcement and punishment observed in others. The principle of reciprocal determinism suggests that the functional relationships between personal, environmental, and behavioral factors act as determinants of addictive behavior. Thus, effective treatment targets each dynamic facet of the biopsychosocial disorder.
=== Transtheoretical model (stages of change model) ===
The transtheoretical model of change suggests that overcoming an addiction is a stepwise process that occurs through several stages.
Precontemplation: This initial stage precedes individuals considering a change in their behavior. They might be oblivious to or in denial of their addiction, failing to recognize the need for change.
Contemplation is the stage in which individuals become aware of the problems caused by their addiction and are considering change. Although they may not fully commit, they weigh the costs and benefits of making a shift.
Preparation: Individuals in this stage are getting ready to change. They might have taken preliminary steps, like gathering information or making small commitments, in preparation for behavioral change.
Action involves actively modifying behavior by making specific, observable changes to address the addictive behavior. The action stage requires significant effort and commitment.
Maintenance: After successfully implementing a change, individuals enter the maintenance stage, where they work to sustain the new behavior and prevent relapse. This stage is characterized by ongoing effort and consolidation of gains.
Termination/relapse prevention: Recognizing that relapse is a common part of the change process, this stage focuses on identifying and addressing factors that may lead to a return to old behaviors. Relapse is viewed as an opportunity for learning and strategy adjustment, with the ultimate goal of eliminating or terminating the targeted behavior.
The transtheoretical model can be helpful in guiding development of tailored behavioral interventions that can promote lasting change. Progression through these stages may not always follow a linear path, as individuals may move back and forth between stages. Resistance to change is recognized as an expected part of the process.
Addiction causes an "astoundingly high financial and human toll" on individuals and society as a whole. In the United States, the total economic cost to society is greater than that of all types of diabetes and all cancers combined. These costs arise from the direct adverse effects of drugs and associated healthcare costs (e.g., emergency medical services and outpatient and inpatient care), long-term complications (e.g., lung cancer from smoking tobacco products, liver cirrhosis and dementia from chronic alcohol consumption, and meth mouth from methamphetamine use), the loss of productivity and associated welfare costs, fatal and non-fatal accidents (e.g., traffic collisions), suicides, homicides, and incarceration, among others. The US National Institute on Drug Abuse has found that overdose deaths in the US have almost tripled among males and females from 2002 to 2017, with 72,306 overdose deaths reported in 2017 in the US. 2020 marked the year with the highest number of overdose deaths over a 12-month period, with 81,000 overdose deaths, exceeding the records set in 2017.
== See also ==
== Endnotes ==
== Notes ==
Image legend
== References ==
== Further reading ==
== External links ==
"The Science of Addiction: Genetics and the Brain". learn.genetics.utah.edu. Learn.Genetics – University of Utah.
Why do our brains get addicted? – a TEDMED 2014 talk by Nora Volkow, the director of the National Institute on Drug Abuse at NIH.
Kyoto Encyclopedia of Genes and Genomes (KEGG) signal transduction pathways:
KEGG – human alcohol addiction
KEGG – human amphetamine addiction
KEGG – human cocaine addiction | Wikipedia/Drug-addiction |
The prohibition of drugs through sumptuary legislation or religious law is a common means of attempting to prevent the recreational use of certain intoxicating substances.
An area has a prohibition of drugs when its government uses the force of law to punish the use or possession of drugs which have been classified as controlled. A government may simultaneously have systems in place to regulate both controlled and non controlled drugs. Regulation controls the manufacture, distribution, marketing, sale, and use of certain drugs, for instance through a prescription system. For example, in some states, the possession or sale of amphetamines is a crime unless a patient has a physician's prescription for the drug; having a prescription authorizes a pharmacy to sell and a patient to use a drug that would otherwise be prohibited. Although prohibition mostly concerns psychoactive drugs (which affect mental processes such as perception, cognition, and mood), prohibition can also apply to non-psychoactive drugs, such as anabolic steroids. Many governments do not criminalize the possession of a limited quantity of certain drugs for personal use, while still prohibiting their sale or manufacture, or possession in large quantities. Some laws (or judicial practice) set a specific volume of a particular drug, above which is considered ipso jure to be evidence of trafficking or sale of the drug.
Some Islamic countries prohibit the use of alcohol (see list of countries with alcohol prohibition). Many governments levy a tax on alcohol and tobacco products, and restrict alcohol and tobacco from being sold or gifted to a minor. Other common restrictions include bans on outdoor drinking and indoor smoking. In the early 20th century, many countries had alcohol prohibition. These include the United States (1920–1933), Finland (1919–1932), Norway (1916–1927), Canada (1901–1948), Iceland (1915–1922) and the Russian Empire/USSR (1914–1925). In fact, the first international treaty to control a psychoactive substance adopted in 1890 actually concerned alcoholic beverages (Brussels Conference). The first treaty on opium only arrived two decades later, in 1912.
== Definitions ==
Drugs, in the context of prohibition, are any of a number of psychoactive substances whose use a government or religious body seeks to control. What constitutes a drug varies by century and belief system. What is a psychoactive substance is relatively well known to modern science. Examples include a range from caffeine found in coffee, tea, and chocolate, nicotine in tobacco products; botanical extracts morphine and heroin, and synthetic compounds MDMA and fentanyl. Almost without exception, these substances also have a medical use, in which case they are called pharmaceutical drugs or just pharmaceuticals. The use of medicine to save or extend life or to alleviate suffering is uncontroversial in most cultures. Prohibition applies to certain conditions of possession or use. Recreational use refers to the use of substances primarily for their psychoactive effect outside of a clinical situation or doctor's care.
In the twenty-first century, caffeine has pharmaceutical uses. Caffeine is used to treat bronchopulmonary dysplasia. In most cultures, caffeine in the form of coffee or tea is unregulated. Over 2.25 billion cups of coffee are consumed in the world every day. Some religions, including the Church of Jesus Christ of Latter-day Saints, prohibit coffee. They believe that it is both physically and spiritually unhealthy to consume coffee.
A government's interest to control a drug may be based on its negative effects on its users, or it may simply have a revenue interest. The British parliament prohibited the possession of untaxed tea with the imposition of the Tea Act of 1773. In this case, as in many others, it is not a substance that is prohibited, but the conditions under which it is possessed or consumed. Those conditions include matters of intent, which makes the enforcement of laws difficult. In Colorado possession of "blenders, bowls, containers, spoons, and mixing devices" is illegal if there was intent to use them with drugs.
Many drugs, beyond their pharmaceutical and recreational uses, have industrial uses. Nitrous oxide, or laughing gas is a dental anesthetic, also used to prepare whipped cream, fuel rocket engines, and enhance the performance of race cars. Ethanol, or drinking alcohol, is also used as a fuel, industrial solvent and disinfectant.
== History ==
The cultivation, use, and trade of psychoactive and other drugs has occurred since ancient times. Concurrently, authorities have often restricted drug possession and trade for a variety of political and religious reasons. In the 20th century, the United States led a major renewed surge in drug prohibition called the "War on Drugs".
=== Early drug laws ===
The prohibition on alcohol under Islamic Sharia law, which is usually attributed to passages in the Qur'an, dates back to the early seventh century. Although Islamic law is often interpreted as prohibiting all intoxicants (not only alcohol), the ancient practice of hashish smoking has continued throughout the history of Islam, against varying degrees of resistance. A major campaign against hashish-eating Sufis were conducted in Egypt in the 11th and 12th centuries resulting among other things in the burning of fields of cannabis.
Though the prohibition of illegal drugs was established under Sharia law, particularly against the use of hashish as a recreational drug, classical jurists of medieval Islamic jurisprudence accepted the use of hashish for medicinal and therapeutic purposes, and agreed that its "medical use, even if it leads to mental derangement, should remain exempt [from punishment]". In the 14th century, the Islamic scholar Az-Zarkashi spoke of "the permissibility of its use for medical purposes if it is established that it is beneficial".
In the Ottoman Empire, Murad IV attempted to prohibit coffee drinking to Muslims as haraam, arguing that it was an intoxicant, but this ruling was overturned soon after he died in 1640. The introduction of coffee in Europe from Muslim Turkey prompted calls for it to be banned as the devil's work, although Pope Clement VIII sanctioned its use in 1600, declaring that it was "so delicious that it would be a pity to let the infidels have exclusive use of it". Bach's Coffee Cantata, from the 1730s, presents a vigorous debate between a girl and her father over her desire to consume coffee. The early association between coffeehouses and seditious political activities in England led to the banning of such establishments in the mid-17th century.
A number of Asian rulers had similarly enacted early prohibitions, many of which were later forcefully overturned by Western colonial powers during the 18th and 19th centuries. In 1360, for example, King Ramathibodi I, of Ayutthaya Kingdom (now Thailand), prohibited opium consumption and trade. The prohibition lasted nearly 500 years until 1851 when King Rama IV allowed Chinese migrants to consume opium. The Konbaung Dynasty prohibited all intoxicants and stimulants during the reign of King Bodawpaya (1781–1819). After Burma became a British colony, the restrictions on opium were abolished and the colonial government established monopolies selling Indian-produced opium.
In late Qing China, opium imported by foreign traders, such as those employed by Jardine Matheson and the East India Company, was consumed by all social classes in Southern China. Between 1821 and 1837, imports of the drug increased fivefold. The wealth drain and widespread social problems that resulted from this consumption prompted the Chinese government to attempt to end the trade. This effort was initially successful, with Lin Zexu ordering the destruction of opium at Humen in June 1839. However, the opium traders lobbied the British government to declare war on China, resulting in the First Opium War. The Qing government was defeated and the war ended with the Treaty of Nanking, which legalized opium trading in Chinese law
=== First modern drug regulations ===
The first modern law in Europe for the regulating of drugs was the Pharmacy Act 1868 in the United Kingdom. There had been previous moves to establish the medical and pharmaceutical professions as separate, self-regulating bodies, but the General Medical Council, established in 1863, unsuccessfully attempted to assert control over drug distribution. The act set controls on the distribution of poisons and drugs. Poisons could only be sold if the purchaser was known to the seller or to an intermediary known to both, and drugs, including opium and all preparations of opium or of poppies, had to be sold in containers with the seller's name and address.
Despite the reservation of opium to professional control, general sales did continue to a limited extent, with mixtures with less than 1 percent opium being unregulated.
After the legislation passed, the death rate caused by opium immediately fell from 6.4 per million population in 1868 to 4.5 in 1869. Deaths among children under five dropped from 20.5 per million population between 1863 and 1867 to 12.7 per million in 1871 and further declined to between 6 and 7 per million in the 1880s.
In the United States, the first drug law was passed in San Francisco in 1875, banning the smoking of opium in opium dens. The reason cited was "many women and young girls, as well as young men of a respectable family, were being induced to visit the Chinese opium-smoking dens, where they were ruined morally and otherwise." This was followed by other laws throughout the country, and federal laws that barred Chinese people from trafficking in opium. Though the laws affected the use and distribution of opium by Chinese immigrants, no action was taken against the producers of such products as laudanum, a tincture of opium and alcohol, commonly taken as a panacea by white Americans. The distinction between its use by white Americans and Chinese immigrants was thus a form of racial discrimination as it was based on the form in which it was ingested: Chinese immigrants tended to smoke it, while it was often included in various kinds of generally liquid medicines often (but not exclusively) used by Americans of European descent. The laws targeted opium smoking, but not other methods of ingestion.
Britain passed the All-India Opium Act of 1878, which limited recreational opium sales to registered Indian opium-eaters and Chinese opium-smokers and prohibiting its sale to emigrant workers from British Burma.
Following the passage of a regional law in 1895, Australia's Aboriginals Protection and Restriction of the Sale of Opium Act 1897 addressed opium addiction among Aborigines, though it soon became a general vehicle for depriving them of basic rights by administrative regulation. Opium sale was prohibited to the general population in 1905, and smoking and possession were prohibited in 1908.
Despite these laws, the late 19th century saw an increase in opiate consumption. This was due to the prescribing and dispensing of legal opiates by physicians and pharmacists to relieve menstruation pain. It is estimated that between 150,000 and 200,000 opiate addicts lived in the United States at the time, and a majority of these addicts were women.
=== Changing attitudes and the drug prohibition campaign ===
Foreign traders, including those employed by Jardine Matheson and the East India Company, smuggled opium into China in order to balance high trade deficits. Chinese attempts to outlaw the trade led to the First Opium War and the subsequent legalization of the trade at the Treaty of Nanking. Attitudes towards the opium trade were initially ambivalent, but in 1874 the Society for the Suppression of the Opium Trade was formed in England by Quakers led by the Rev. Frederick Storrs-Turner. By the 1890s, increasingly strident campaigns were waged by Protestant missionaries in China for its abolition. The first such society was established at the 1890 Shanghai Missionary Conference, where British and American representatives, including John Glasgow Kerr, Arthur E. Moule, Arthur Gostick Shorrock and Griffith John, agreed to establish the Permanent Committee for the Promotion of Anti-Opium Societies.
Due to increasing pressure in the British parliament, the Liberal government under William Ewart Gladstone approved the appointment of a Royal Commission on Opium to India in 1893. The commission was tasked with ascertaining the impact of Indian opium exports to the Far East, and to advise whether the trade should be banned and opium consumption itself banned in India. After an extended inquiry, the Royal Commission rejected the claims made by the anti-opium campaigners regarding the supposed societal harm caused by the trade and the issue was finalized for another 15 years.
The missionary organizations were outraged over the Royal Commission on Opium's conclusions and set up the Anti-Opium League in China; the league gathered data from every Western-trained medical doctor in China and published Opinions of Over 100 Physicians on the Use of Opium in China. This was the first anti-drug campaign to be based on scientific principles, and it had a tremendous impact on the state of educated opinion in the West. In England, the home director of the China Inland Mission, Benjamin Broomhall, was an active opponent of the opium trade, writing two books to promote the banning of opium smoking: The Truth about Opium Smoking and The Chinese Opium Smoker. In 1888, Broomhall formed and became secretary of the Christian Union for the Severance of the British Empire with the Opium Traffic and editor of its periodical, National Righteousness. He lobbied the British parliament to ban the opium trade. Broomhall and James Laidlaw Maxwell appealed to the London Missionary Conference of 1888 and the Edinburgh Missionary Conference of 1910 to condemn the continuation of the trade. As Broomhall lay dying, an article from The Times was read to him with the welcome news that an international agreement had been signed ensuring the end of the opium trade within two years.
In 1906, a motion to 'declare the opium trade "morally indefensible" and remove Government support for it', initially unsuccessfully proposed by Arthur Pease in 1891, was put before the House of Commons. This time the motion passed. The Qing government banned opium soon afterward.
These changing attitudes led to the founding of the International Opium Commission in 1909. An International Opium Convention was signed by 13 nations at The Hague on January 23, 1912, during the First International Opium Conference. This was the first international drug control treaty and it was registered in the League of Nations Treaty Series on January 23, 1922. The Convention provided that "The contracting Powers shall use their best endeavors to control or to cause to be controlled, all person manufacturing, importing, selling, distributing, and exporting morphine, cocaine, and their respective salts, as well as the buildings in which these persons carry such an industry or trade."
The treaty became international law in 1919 when it was incorporated into the Treaty of Versailles. The role of the commission was passed to the League of Nations, and all signatory nations agreed to prohibit the import, sale, distribution, export, and use of all narcotic drugs, except for medical and scientific purposes.
=== Prohibition ===
In the UK the Defence of the Realm Act 1914, passed at the onset of the First World War, gave the government wide-ranging powers to requisition the property and to criminalize specific activities. A moral panic was whipped up by the press in 1916 over the alleged sale of drugs to the troops of the British Indian Army. With the temporary powers of DORA, the Army Council quickly banned the sale of all psychoactive drugs to troops, unless required for medical reasons. However, shifts in the public attitude towards drugs—they were beginning to be associated with prostitution, vice and immorality—led the government to pass further unprecedented laws, banning and criminalising the possession and dispensation of all narcotics, including opium and cocaine. After the war, this legislation was maintained and strengthened with the passing of the Dangerous Drugs Act 1920 (10 & 11 Geo. 5. c. 46). Home Office control was extended to include raw opium, morphine, cocaine, ecogonine and heroin.
Hardening of Canadian attitudes toward Chinese-Canadian opium users and fear of a spread of the drug into the white population led to the effective criminalization of opium for nonmedical use in Canada between 1908 and the mid-1920s.
The Mao Zedong government nearly eradicated both consumption and production of opium during the 1950s using social control and isolation. Ten million addicts were forced into compulsory treatment, dealers were executed, and opium-producing regions were planted with new crops. Remaining opium production shifted south of the Chinese border into the Golden Triangle region. The remnant opium trade primarily served Southeast Asia, but spread to American soldiers during the Vietnam War, with 20 percent of soldiers regarding themselves as addicted during the peak of the epidemic in 1971. In 2003, China was estimated to have four million regular drug users and one million registered drug addicts.
In the US, the Harrison Act was passed in 1914, and required sellers of opiates and cocaine to get a license. While originally intended to regulate the trade, it soon became a prohibitive law, eventually becoming legal precedent that any prescription for a narcotic given by a physician or pharmacist – even in the course of medical treatment for addiction – constituted conspiracy to violate the Harrison Act. In 1919, the Supreme Court ruled in Doremus that the Harrison Act was constitutional and in Webb that physicians could not prescribe narcotics solely for maintenance. In Jin Fuey Moy v. United States, the court upheld that it was a violation of the Harrison Act even if a physician provided prescription of a narcotic for an addict, and thus subject to criminal prosecution. This is also true of the later Marijuana Tax Act in 1937. Soon, however, licensing bodies did not issue licenses, effectively banning the drugs.
The American judicial system did not initially accept drug prohibition. Prosecutors argued that possessing drugs was a tax violation, as no legal licenses to sell drugs were in existence; hence, a person possessing drugs must have purchased them from an unlicensed source. After some wrangling, this was accepted as federal jurisdiction under the interstate commerce clause of the U.S. Constitution.
==== Alcohol prohibition ====
The prohibition of alcohol commenced in Finland in 1919 and in the United States in 1920. Because alcohol was the most popular recreational drug in these countries, reactions to its prohibition were far more negative than to the prohibition of other drugs, which were commonly associated with ethnic minorities, prostitution, and vice. Public pressure led to the repeal of alcohol prohibition in Finland in 1932, and in the United States in 1933. Residents of many provinces of Canada also experienced alcohol prohibition for similar periods in the first half of the 20th century.
In Sweden, a referendum in 1922 decided against an alcohol prohibition law (with 51% of the votes against and 49% for prohibition), but starting in 1914 (nationwide from 1917) and until 1955 Sweden employed an alcohol rationing system with personal liquor ration books ("motbok").
=== War on Drugs ===
In response to rising drug use among young people and the counterculture movement, government efforts to enforce prohibition were strengthened in many countries from the 1960s onward. Support at an international level for the prohibition of psychoactive drug use became a consistent feature of United States policy during both Republican and Democratic administrations, to such an extent that US support for foreign governments has often been contingent on their adherence to US drug policy. Major milestones in this campaign include the introduction of the Single Convention on Narcotic Drugs in 1961, the Convention on Psychotropic Substances in 1971 and the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances in 1988. A few developing countries where consumption of the prohibited substances has enjoyed longstanding cultural support, long resisted such outside pressure to pass legislation adhering to these conventions. Nepal only did so in 1976.
In 1972, United States President Richard Nixon announced the commencement of the so-called "War on Drugs". Later, President Reagan added the position of drug czar to the President's Executive Office. In 1973, New York introduced mandatory minimum sentences of 15 years to life imprisonment for possession of more than 113 grams (4 oz) of a so-called hard drug, called the Rockefeller drug laws after New York Governor and later Vice President Nelson Rockefeller. Similar laws were introduced across the United States.
California's broader 'three strikes and you're out' policy adopted in 1994 was the first mandatory sentencing policy to gain widespread publicity and was subsequently adopted in most United States jurisdictions. This policy mandates life imprisonment for a third criminal conviction of any felony offense. A similar 'three strikes' policy was introduced to the United Kingdom by the Conservative government in 1997. This legislation enacted a mandatory minimum sentence of seven years for those convicted for a third time of a drug trafficking offense involving a class A drug.
=== Calls for legalization, relegalization or decriminalization ===
The terms relegalization, legalization, legal regulations, or decriminalization are used with very different meanings by different authors, something that can be confusing when the claims are not specified. Here are some variants:
Sales of one or more drugs (e.g., marijuana) for personal use become legal, at least if sold in a certain way.
Sales of an extracts with a specific substance become legal sold in a certain way, for example on prescription.
Use or possession of small amounts for personal use do not lead to incarceration if it is the only crime, but it is still illegal; the court or the prosecutor can impose a fine. (In that sense, Sweden both legalized and supported drug prohibition simultaneously.)
Use or possession of small amounts for personal use do not lead to incarceration. The case is not treated in an ordinary court, but by a commission that may recommend treatment or sanctions including fines. (In that sense, Portugal both legalized and supported drug prohibitions).
There are efforts around the world to promote the relegalization and decriminalization of drugs. These policies are often supported by proponents of liberalism and libertarianism on the grounds of individual freedom, as well as by leftists who believe prohibition to be a method of suppression of the working class by the ruling class.
Prohibition of drugs is supported by proponents of conservatism as well various NGOs. A number of NGOs are aligned in support of drug prohibition as members of the World Federation Against Drugs. In the WFAD constitution, the "Declaration of the World Forum Against Drugs" (2008) advocates for "no other goal than a drug-free world", and states that a balanced policy of drug abuse prevention, education, treatment, law enforcement, research, and supply reduction provides the most effective platform to reduce drug abuse and its associated harms and calls on governments to consider demand reduction as one of their first priorities. It supports the UN drug conventions, the inclusion of cannabis as one of the "hard drugs", and the use of criminal sanctions "when appropriate" to deter drug use. It opposes legalization in any form, and harm reduction in general.
According to some critics, drug prohibition is responsible for enriching "organised criminal networks" while the hypothesis that the prohibition of drugs generates violence is consistent with research done over long time-series and cross-country facts.
In the United Kingdom, where the principal piece of drug prohibition legislation is the Misuse of Drugs Act 1971, criticism includes:
Drug classification: making a hash of it?, Fifth Report of Session 2005–06, House of Commons Science and Technology Committee, which said that the present system of drug classification is based on historical assumptions, not scientific assessment
Development of a rational scale to assess the harm of drugs of potential misuse, David Nutt, Leslie A. King, William Saulsbury, Colin Blakemore, The Lancet, 24 March 2007, said the act is "not fit for purpose" and "the exclusion of alcohol and tobacco from the Misuse of Drugs Act is, from a scientific perspective, arbitrary"
The Drug Equality Alliance (DEA) argue that the Government is administering the Act arbitrarily, contrary to its purpose, contrary to the original wishes of Parliament and therefore illegally. They are currently assisting and supporting several legal challenges to this alleged maladministration.
In February 2008 the then-president of Honduras, Manuel Zelaya, called on the world to legalize drugs, in order, he said, to prevent the majority of violent murders occurring in Honduras. Honduras is used by cocaine smugglers as a transiting point between Colombia and the US. Honduras, with a population of 7 million, suffers an average of 8–10 murders a day, with an estimated 70% being a result of this international drug trade. The same problem is occurring in Guatemala, El Salvador, Costa Rica and Mexico, according to Zelaya. In January 2012 Colombian President Juan Manuel Santos made a plea to the United States and Europe to start a global debate about legalizing drugs. This call was echoed by the Guatemalan President Otto Pérez Molina, who announced his desire to legalize drugs, saying "What I have done is put the issue back on the table."
In a report dealing with HIV in June 2014, the World Health Organization (WHO) of the UN called for the decriminalization of drugs particularly including injected ones. This conclusion put WHO at odds with broader long-standing UN policy favoring criminalization. Eight states of the United States (Alaska, California, Colorado, Maine, Massachusetts, Nevada, Oregon, and Washington), as well as the District of Columbia, have legalized the sale of marijuana for personal recreational use as of 2017, although recreational use remains illegal under U.S. federal law. The conflict between state and federal law is, as of 2018, unresolved.
Since Uruguay in 2014 and Canada in 2018 legalized cannabis, the debate has known a new turn internationally.
On March 14th, 2025, the United Nations Commission on Narcotic Drugs decided to create a panel of independent experts to rethink the global drug control regime.
== Drug prohibition laws ==
The following individual drugs, listed under their respective family groups (e.g., barbiturates, benzodiazepines, opiates), are the most frequently sought after by drug users and as such are prohibited or otherwise heavily regulated for use in many countries:
Among the barbiturates, pentobarbital (Nembutal), secobarbital (Seconal), and amobarbital (Amytal)
Among the benzodiazepines, temazepam (Restoril; Normison; Euhypnos), flunitrazepam (Rohypnol; Hypnor; Flunipam), and alprazolam (Xanax)
Cannabis products, e.g., marijuana, hashish, and hashish oil
Among the dissociatives, phencyclidine (PCP), and ketamine are the most sought after.
hallucinogens such as LSD, mescaline, peyote, and psilocybin
Empathogen-entactogen drugs like MDMA ("ecstasy")
Among the narcotics, it is opiates such as morphine and codeine, and opioids such as diacetylmorphine (Heroin), hydrocodone (Vicodin; Hycodan), oxycodone (Percocet; Oxycontin), hydromorphone (Dilaudid), and oxymorphone (Opana).
Sedatives such as GHB and methaqualone (Quaalude)
Stimulants such as cocaine, amphetamine (Adderall), dextroamphetamine (Dexedrine), methamphetamine (Desoxyn), methcathinone, and methylphenidate (Ritalin)
The regulation of the above drugs varies in many countries. Alcohol possession and consumption by adults is today widely banned only in Islamic countries and certain states of India. Although alcohol prohibition was eventually repealed in the countries that enacted it, there are, for example, still parts of the United States that do not allow alcohol sales, though alcohol possession may be legal (see dry counties). New Zealand has banned the importation of chewing tobacco as part of the Smoke-free Environments Act 1990. In some parts of the world, provisions are made for the use of traditional sacraments like ayahuasca, iboga, and peyote. In Gabon, iboga (tabernanthe iboga) has been declared a national treasure and is used in rites of the Bwiti religion. The active ingredient, ibogaine, is proposed as a treatment of opioid withdrawal and various substance use disorders.
In countries where alcohol and tobacco are legal, certain measures are frequently undertaken to discourage use of these drugs. For example, packages of alcohol and tobacco sometimes communicate warnings directed towards the consumer, communicating the potential risks of partaking in the use of the substance. These drugs also frequently have special sin taxes associated with the purchase thereof, in order to recoup the losses associated with public funding for the health problems the use causes in long-term users. Restrictions on advertising also exist in many countries, and often a state holds a monopoly on manufacture, distribution, marketing, and/or the sale of these drugs.
=== List of principal drug prohibition laws by jurisdiction (non-exhaustive) ===
Australia: Standard for the Uniform Scheduling of Medicines and Poisons
Bangladesh: Narcotics Substances Control Act, 2018
Belize: Misuse of Drugs Act (Belize)
Canada: Controlled Drugs and Substances Act
Estonia: Narcotic Drugs and Psychotropic Substances Act (Estonia)
Germany: Narcotic Drugs Act
India: Narcotic Drugs and Psychotropic Substances Act (India)
Netherlands: Opium Law
New Zealand: Misuse of Drugs Act 1975
Pakistan: Control of Narcotic Substances Act 1997
Philippines: Comprehensive Dangerous Drugs Act of 2002
Poland: Drug Abuse Prevention Act 2005
Portugal: Decree-Law 15/93
Ireland: Misuse of Drugs Act (Ireland)
South Africa: Drugs and Drug Trafficking Act 1992
Singapore: Misuse of Drugs Act (Singapore)
Sweden: Lag om kontroll av narkotika (SFS 1992:860)
Thailand: Psychotropic Substances Act (Thailand) and Narcotics Act
United Kingdom: Misuse of Drugs Act 1971 and Drugs Act 2005
United States: Controlled Substances Act
International: Single Convention on Narcotic Drugs
=== Legal dilemmas ===
The sentencing statutes in the United States Code that cover controlled substances are complicated. For example, a first-time offender convicted in a single proceeding for selling marijuana three times, and found to have carried a gun on him all three times (even if it were not used) is subject to a minimum sentence of 55 years in federal prison.
In Hallucinations: Behavior, Experience, and Theory (1975), senior US government researchers Louis Jolyon West and Ronald K. Siegel explain how drug prohibition can be used for selective social control:
The role of drugs in the exercise of political control is also coming under increasing discussion. Control can be through prohibition or supply. The total or even partial prohibition of drugs gives the government considerable leverage for other types of control. An example would be the selective application of drug laws ... against selected components of the population such as members of certain minority groups or political organizations.
Linguist Noam Chomsky argues that drug laws are currently, and have historically been, used by the state to oppress sections of society it opposes:
Very commonly substances are criminalized because they're associated with what's called the dangerous classes, poor people, or working people. So for example in England in the 19th century, there was a period when gin was criminalized and whiskey wasn't, because gin is what poor people drink.
=== Legal highs and prohibition ===
In 2013 the European Monitoring Centre for Drugs and Drug Addiction reported that there are 280 new legal drugs, known as "legal highs", available in Europe. One of the best known, mephedrone, was banned in the United Kingdom in 2010. On November 24, 2010, the U.S. Drug Enforcement Administration announced it would use emergency powers to ban many synthetic cannabinoids within a month. An estimated 73 new psychoactive synthetic drugs appeared on the UK market in 2012. The response of the Home Office has been to create a temporary class drug order which bans the manufacture, import, and supply (but not the possession) of named substances.
=== Corruption ===
In certain countries, there is concern that campaigns against drugs and organized crime are a cover for corrupt officials tied to drug trafficking themselves. In the United States, Federal Bureau of Narcotics chief Harry Anslinger's opponents accused him of taking bribes from the Mafia to enact prohibition and create a black market for alcohol. More recently in the Philippines, one death squad hitman told author Niko Vorobyov that he was being paid by military officers to eliminate those drug dealers who failed to pay a 'tax'. Under President Rodrigo Duterte, the Philippines has waged a bloody war against drugs that may have resulted in up to 29,000 extrajudicial killings.
When it comes to social control with cannabis, there are different aspects to consider. Not only do we assess legislative leaders and the way they vote on cannabis, but we also must consider the federal regulations and taxation that contribute to social controls. For instance, according to a report on the U.S. customs and border protections, the American industry, although banned the main usage of marijuana, was still using products similar such as hemp seeds, oils etc. leading to the previously discussed marijuana tax act.
The Tax act provisions required importers to register and pay an annual tax of $24 and receive an official stamp. Stamps for Products were then affixed to each original order form and recorded by the state revenue collector. Then, a customs collector was to maintain the custody of imported marijuana at entry ports until required documents were received, reviewed and approved.Shipments were subject to searches, seizures and forfeitures if any provisions of the law were not met. Violations would result in fines of no more than $2000 or potential imprisonment for up to 5 years. Oftentimes, this created opportunity for corruption, stolen imports that would later lead to smuggling, oftentimes by state officials and tight knit elitists.
== Penalties ==
=== United States ===
Drug possession is the crime of having one or more illegal drugs in one's possession, either for personal use, distribution, sale or otherwise. Illegal drugs fall into different categories and sentences vary depending on the amount, type of drug, circumstances, and jurisdiction. In the U.S., the penalty for illegal drug possession and sale can vary from a small fine to a prison sentence. In some states, marijuana possession is considered to be a petty offense, with the penalty being comparable to that of a speeding violation. In some municipalities, possessing a small quantity of marijuana in one's own home is not punishable at all. Generally, however, drug possession is an arrestable offense, although first-time offenders rarely serve jail time. Federal law makes even possession of "soft drugs", such as cannabis, illegal, though some local governments have laws contradicting federal laws.
In the U.S., the War on Drugs is thought to be contributing to a prison overcrowding problem. In 1996, 59.6% of prisoners were drug-related criminals. The U.S. population grew by about +25% from 1980 to 2000. In that same 20 year time period, the U.S. prison population tripled, making the U.S. the world leader in both percentage and absolute number of citizens incarcerated. The United States has 5% of the world's population, but 25% of the prisoners.
About 90% of United States prisoners are incarcerated in state jails. In 2016, about 572,000, over 44%, of the 1.3 million people in these state jails, were serving time for drug offenses. 728,000 were incarcerated for violent offenses.
The data from Federal Bureau of Prisons online statistics page states that 45.9% of prisoners were incarcerated for drug offenses, as of December 2021.
=== European Union ===
In 2004, the Council of the European Union adopted a framework decision harmonizing the minimum penal provisions for illicit drug-related activities. In particular, article 2(9) stipulates that activities may be exempt from the minimum provisions "when it is committed by its perpetrators exclusively for their own personal consumption as defined by national law." This was made, in particular, to accommodate more liberal national systems such as the Dutch coffee shops (see below) or the Spanish Cannabis Social Clubs.
==== The Netherlands ====
In the Netherlands, cannabis and other "soft" drugs are decriminalised in small quantities. The Dutch government treats the problem as more of a public health issue than a criminal issue. Contrary to popular belief, cannabis is still technically illegal. Coffee shops that sell cannabis to people 18 or above are tolerated, and pay taxes like any other business for their cannabis and hashish sales, although distribution is a grey area that the authorities would rather not go into as it is not decriminalised. Many "coffee shops" are found in Amsterdam and cater mainly to the large tourist trade; the local consumption rate is far lower than in the US.
The administrative bodies responsible for enforcing the drug policies include the Ministry of Health, Welfare and Sport, the Ministry of Justice, the Ministry of the Interior and Kingdom Relations, and the Ministry of Finance. Local authorities also shape local policy, within the national framework.
When compared to other countries, Dutch drug consumption falls in the European average at six per cent regular use (twenty-one per cent at some point in life) and considerably lower than the Anglo-Saxon countries headed by the United States with an eight per cent recurring use (thirty-four at some point in life).
=== Australia ===
A Nielsen poll in 2012 found that only 27% of voters favoured decriminalisation. Australia has steep penalties for growing and using drugs even for personal use. with Western Australia having the toughest laws. There is an associated anti-drug culture amongst a significant number of Australians. Law enforcement targets drugs, particularly in the party scene. In 2012, crime statistics in Victoria revealed that police were increasingly arresting users rather than dealers, and the Liberal government banned the sale of bongs that year.
=== Indonesia ===
Indonesia carries a maximum penalty of death for drug dealing, and a maximum of 15 years prison for drug use. In 2004, Australian citizen Schapelle Corby was convicted of smuggling 4.4 kilograms of cannabis into Bali, a crime that carried a maximum penalty of death. Her trial reached the verdict of guilty with a punishment of 20 years imprisonment. Corby claimed to be an unwitting drug mule. Australian citizens known as the "Bali Nine" were caught smuggling heroin. Two of the nine, Andrew Chan and Myuran Sukumaran, were executed April 29, 2015 along with six other foreign nationals. In August 2005, Australian model Michelle Leslie was arrested with two ecstasy pills. She pleaded guilty to possession and in November 2005 was sentenced to 3 months imprisonment, which she was deemed to have already served, and was released from prison immediately upon her admission of guilt on the charge of possession.
At the 1961 Single Convention on Narcotic Drugs, Indonesia, along with India, Turkey, Pakistan and some South American countries opposed the criminalisation of drugs.
=== Republic of China (Taiwan) ===
Taiwan carries a maximum penalty of death for drug trafficking, while smoking tobacco and wine are classified as legal entertainment drug. The Department of Health is in charge of drug prohibition.
== Cost ==
In 2020, the direct cost of drug prohibition to United States taxpayers was estimated at over $40 billion annually. Prohibition can increase organized crime, government corruption, and mass incarceration via the trade in illegal drugs, while racial and gender disparities in enforcement are evident.
Although drug prohibition is often portrayed by proponents as a measure to improve public health, evidence is lacking. In 2016, the Johns Hopkins–Lancet Commission concluded that the "harms of prohibition far outweigh the benefits", citing increased risk of overdoses and HIV infection and detrimental effects on the social determinants of health. Some proponents argue that drug prohibition's effect on suppressing usage rates (although the magnitude of this effect is unknown) outweighs the negative effects of prohibition.
Alternative approaches to prohibition include drug legalization, drug decriminalization, and government monopoly.
== See also ==
Alcohol law
Arguments for and against drug prohibition
Chasing the Scream
Drug liberalization
Demand reduction
Drug policy of the Soviet Union
Harm reduction
List of anti-cannabis organizations
Medellín Cartel
Mexican drug war
Puerto Rican drug war
Prohibitionism
Tobacco control
War on Drugs
US specific:
Allegations of CIA drug trafficking
School district drug policies
Drug Free America Foundation
Drug Policy Alliance
DrugWarRant
Gary Webb
Marijuana Policy Project
National Organization for the Reform of Marijuana Laws
Students for Sensible Drug Policy
Woman's Christian Temperance Union
== References ==
== Further reading ==
== External links ==
Making Contact: The Mission to End Prohibition. Radio piece featuring LEAP founder and former narcotics officer Jack Cole, and Drug Policy Alliance founder Ethan Nadelmann
EMCDDA – Decriminalisation in Europe? Recent developments in legal approaches to drug use Archived January 12, 2007, at the Wayback Machine.
10 Downing Street's Strategy Unit Drugs Report
War on drugs Archived April 30, 2011, at the Wayback Machine Part I: Winners, documentary (50 min) explaining 'War on Drugs' by Tegenlicht of VPRO Dutch television. After short introduction in Dutch (1 min), English spoken. Broadband internet needed.
War on drugs Archived April 30, 2011, at the Wayback Machine Part II: Losers, documentary (50 min) showing downside of the 'War on Drugs' by Tegenlicht of VPRO Dutch television. After short introduction in Dutch (1 min), English spoken. Broadband internet needed.
After the War on Drugs: Options for Control (Report)
The Drug War as a Socialist Enterprise by Milton Friedman
Free from the Nightmare of Prohibition Archived February 23, 2006, at the Wayback Machine by Harry Browne
Prohibition news page – Alcohol and Drugs History Society
Drugs and conservatives should go together | Wikipedia/Drug_prohibition_laws |
The prohibition of drugs through sumptuary legislation or religious law is a common means of attempting to prevent the recreational use of certain intoxicating substances.
An area has a prohibition of drugs when its government uses the force of law to punish the use or possession of drugs which have been classified as controlled. A government may simultaneously have systems in place to regulate both controlled and non controlled drugs. Regulation controls the manufacture, distribution, marketing, sale, and use of certain drugs, for instance through a prescription system. For example, in some states, the possession or sale of amphetamines is a crime unless a patient has a physician's prescription for the drug; having a prescription authorizes a pharmacy to sell and a patient to use a drug that would otherwise be prohibited. Although prohibition mostly concerns psychoactive drugs (which affect mental processes such as perception, cognition, and mood), prohibition can also apply to non-psychoactive drugs, such as anabolic steroids. Many governments do not criminalize the possession of a limited quantity of certain drugs for personal use, while still prohibiting their sale or manufacture, or possession in large quantities. Some laws (or judicial practice) set a specific volume of a particular drug, above which is considered ipso jure to be evidence of trafficking or sale of the drug.
Some Islamic countries prohibit the use of alcohol (see list of countries with alcohol prohibition). Many governments levy a tax on alcohol and tobacco products, and restrict alcohol and tobacco from being sold or gifted to a minor. Other common restrictions include bans on outdoor drinking and indoor smoking. In the early 20th century, many countries had alcohol prohibition. These include the United States (1920–1933), Finland (1919–1932), Norway (1916–1927), Canada (1901–1948), Iceland (1915–1922) and the Russian Empire/USSR (1914–1925). In fact, the first international treaty to control a psychoactive substance adopted in 1890 actually concerned alcoholic beverages (Brussels Conference). The first treaty on opium only arrived two decades later, in 1912.
== Definitions ==
Drugs, in the context of prohibition, are any of a number of psychoactive substances whose use a government or religious body seeks to control. What constitutes a drug varies by century and belief system. What is a psychoactive substance is relatively well known to modern science. Examples include a range from caffeine found in coffee, tea, and chocolate, nicotine in tobacco products; botanical extracts morphine and heroin, and synthetic compounds MDMA and fentanyl. Almost without exception, these substances also have a medical use, in which case they are called pharmaceutical drugs or just pharmaceuticals. The use of medicine to save or extend life or to alleviate suffering is uncontroversial in most cultures. Prohibition applies to certain conditions of possession or use. Recreational use refers to the use of substances primarily for their psychoactive effect outside of a clinical situation or doctor's care.
In the twenty-first century, caffeine has pharmaceutical uses. Caffeine is used to treat bronchopulmonary dysplasia. In most cultures, caffeine in the form of coffee or tea is unregulated. Over 2.25 billion cups of coffee are consumed in the world every day. Some religions, including the Church of Jesus Christ of Latter-day Saints, prohibit coffee. They believe that it is both physically and spiritually unhealthy to consume coffee.
A government's interest to control a drug may be based on its negative effects on its users, or it may simply have a revenue interest. The British parliament prohibited the possession of untaxed tea with the imposition of the Tea Act of 1773. In this case, as in many others, it is not a substance that is prohibited, but the conditions under which it is possessed or consumed. Those conditions include matters of intent, which makes the enforcement of laws difficult. In Colorado possession of "blenders, bowls, containers, spoons, and mixing devices" is illegal if there was intent to use them with drugs.
Many drugs, beyond their pharmaceutical and recreational uses, have industrial uses. Nitrous oxide, or laughing gas is a dental anesthetic, also used to prepare whipped cream, fuel rocket engines, and enhance the performance of race cars. Ethanol, or drinking alcohol, is also used as a fuel, industrial solvent and disinfectant.
== History ==
The cultivation, use, and trade of psychoactive and other drugs has occurred since ancient times. Concurrently, authorities have often restricted drug possession and trade for a variety of political and religious reasons. In the 20th century, the United States led a major renewed surge in drug prohibition called the "War on Drugs".
=== Early drug laws ===
The prohibition on alcohol under Islamic Sharia law, which is usually attributed to passages in the Qur'an, dates back to the early seventh century. Although Islamic law is often interpreted as prohibiting all intoxicants (not only alcohol), the ancient practice of hashish smoking has continued throughout the history of Islam, against varying degrees of resistance. A major campaign against hashish-eating Sufis were conducted in Egypt in the 11th and 12th centuries resulting among other things in the burning of fields of cannabis.
Though the prohibition of illegal drugs was established under Sharia law, particularly against the use of hashish as a recreational drug, classical jurists of medieval Islamic jurisprudence accepted the use of hashish for medicinal and therapeutic purposes, and agreed that its "medical use, even if it leads to mental derangement, should remain exempt [from punishment]". In the 14th century, the Islamic scholar Az-Zarkashi spoke of "the permissibility of its use for medical purposes if it is established that it is beneficial".
In the Ottoman Empire, Murad IV attempted to prohibit coffee drinking to Muslims as haraam, arguing that it was an intoxicant, but this ruling was overturned soon after he died in 1640. The introduction of coffee in Europe from Muslim Turkey prompted calls for it to be banned as the devil's work, although Pope Clement VIII sanctioned its use in 1600, declaring that it was "so delicious that it would be a pity to let the infidels have exclusive use of it". Bach's Coffee Cantata, from the 1730s, presents a vigorous debate between a girl and her father over her desire to consume coffee. The early association between coffeehouses and seditious political activities in England led to the banning of such establishments in the mid-17th century.
A number of Asian rulers had similarly enacted early prohibitions, many of which were later forcefully overturned by Western colonial powers during the 18th and 19th centuries. In 1360, for example, King Ramathibodi I, of Ayutthaya Kingdom (now Thailand), prohibited opium consumption and trade. The prohibition lasted nearly 500 years until 1851 when King Rama IV allowed Chinese migrants to consume opium. The Konbaung Dynasty prohibited all intoxicants and stimulants during the reign of King Bodawpaya (1781–1819). After Burma became a British colony, the restrictions on opium were abolished and the colonial government established monopolies selling Indian-produced opium.
In late Qing China, opium imported by foreign traders, such as those employed by Jardine Matheson and the East India Company, was consumed by all social classes in Southern China. Between 1821 and 1837, imports of the drug increased fivefold. The wealth drain and widespread social problems that resulted from this consumption prompted the Chinese government to attempt to end the trade. This effort was initially successful, with Lin Zexu ordering the destruction of opium at Humen in June 1839. However, the opium traders lobbied the British government to declare war on China, resulting in the First Opium War. The Qing government was defeated and the war ended with the Treaty of Nanking, which legalized opium trading in Chinese law
=== First modern drug regulations ===
The first modern law in Europe for the regulating of drugs was the Pharmacy Act 1868 in the United Kingdom. There had been previous moves to establish the medical and pharmaceutical professions as separate, self-regulating bodies, but the General Medical Council, established in 1863, unsuccessfully attempted to assert control over drug distribution. The act set controls on the distribution of poisons and drugs. Poisons could only be sold if the purchaser was known to the seller or to an intermediary known to both, and drugs, including opium and all preparations of opium or of poppies, had to be sold in containers with the seller's name and address.
Despite the reservation of opium to professional control, general sales did continue to a limited extent, with mixtures with less than 1 percent opium being unregulated.
After the legislation passed, the death rate caused by opium immediately fell from 6.4 per million population in 1868 to 4.5 in 1869. Deaths among children under five dropped from 20.5 per million population between 1863 and 1867 to 12.7 per million in 1871 and further declined to between 6 and 7 per million in the 1880s.
In the United States, the first drug law was passed in San Francisco in 1875, banning the smoking of opium in opium dens. The reason cited was "many women and young girls, as well as young men of a respectable family, were being induced to visit the Chinese opium-smoking dens, where they were ruined morally and otherwise." This was followed by other laws throughout the country, and federal laws that barred Chinese people from trafficking in opium. Though the laws affected the use and distribution of opium by Chinese immigrants, no action was taken against the producers of such products as laudanum, a tincture of opium and alcohol, commonly taken as a panacea by white Americans. The distinction between its use by white Americans and Chinese immigrants was thus a form of racial discrimination as it was based on the form in which it was ingested: Chinese immigrants tended to smoke it, while it was often included in various kinds of generally liquid medicines often (but not exclusively) used by Americans of European descent. The laws targeted opium smoking, but not other methods of ingestion.
Britain passed the All-India Opium Act of 1878, which limited recreational opium sales to registered Indian opium-eaters and Chinese opium-smokers and prohibiting its sale to emigrant workers from British Burma.
Following the passage of a regional law in 1895, Australia's Aboriginals Protection and Restriction of the Sale of Opium Act 1897 addressed opium addiction among Aborigines, though it soon became a general vehicle for depriving them of basic rights by administrative regulation. Opium sale was prohibited to the general population in 1905, and smoking and possession were prohibited in 1908.
Despite these laws, the late 19th century saw an increase in opiate consumption. This was due to the prescribing and dispensing of legal opiates by physicians and pharmacists to relieve menstruation pain. It is estimated that between 150,000 and 200,000 opiate addicts lived in the United States at the time, and a majority of these addicts were women.
=== Changing attitudes and the drug prohibition campaign ===
Foreign traders, including those employed by Jardine Matheson and the East India Company, smuggled opium into China in order to balance high trade deficits. Chinese attempts to outlaw the trade led to the First Opium War and the subsequent legalization of the trade at the Treaty of Nanking. Attitudes towards the opium trade were initially ambivalent, but in 1874 the Society for the Suppression of the Opium Trade was formed in England by Quakers led by the Rev. Frederick Storrs-Turner. By the 1890s, increasingly strident campaigns were waged by Protestant missionaries in China for its abolition. The first such society was established at the 1890 Shanghai Missionary Conference, where British and American representatives, including John Glasgow Kerr, Arthur E. Moule, Arthur Gostick Shorrock and Griffith John, agreed to establish the Permanent Committee for the Promotion of Anti-Opium Societies.
Due to increasing pressure in the British parliament, the Liberal government under William Ewart Gladstone approved the appointment of a Royal Commission on Opium to India in 1893. The commission was tasked with ascertaining the impact of Indian opium exports to the Far East, and to advise whether the trade should be banned and opium consumption itself banned in India. After an extended inquiry, the Royal Commission rejected the claims made by the anti-opium campaigners regarding the supposed societal harm caused by the trade and the issue was finalized for another 15 years.
The missionary organizations were outraged over the Royal Commission on Opium's conclusions and set up the Anti-Opium League in China; the league gathered data from every Western-trained medical doctor in China and published Opinions of Over 100 Physicians on the Use of Opium in China. This was the first anti-drug campaign to be based on scientific principles, and it had a tremendous impact on the state of educated opinion in the West. In England, the home director of the China Inland Mission, Benjamin Broomhall, was an active opponent of the opium trade, writing two books to promote the banning of opium smoking: The Truth about Opium Smoking and The Chinese Opium Smoker. In 1888, Broomhall formed and became secretary of the Christian Union for the Severance of the British Empire with the Opium Traffic and editor of its periodical, National Righteousness. He lobbied the British parliament to ban the opium trade. Broomhall and James Laidlaw Maxwell appealed to the London Missionary Conference of 1888 and the Edinburgh Missionary Conference of 1910 to condemn the continuation of the trade. As Broomhall lay dying, an article from The Times was read to him with the welcome news that an international agreement had been signed ensuring the end of the opium trade within two years.
In 1906, a motion to 'declare the opium trade "morally indefensible" and remove Government support for it', initially unsuccessfully proposed by Arthur Pease in 1891, was put before the House of Commons. This time the motion passed. The Qing government banned opium soon afterward.
These changing attitudes led to the founding of the International Opium Commission in 1909. An International Opium Convention was signed by 13 nations at The Hague on January 23, 1912, during the First International Opium Conference. This was the first international drug control treaty and it was registered in the League of Nations Treaty Series on January 23, 1922. The Convention provided that "The contracting Powers shall use their best endeavors to control or to cause to be controlled, all person manufacturing, importing, selling, distributing, and exporting morphine, cocaine, and their respective salts, as well as the buildings in which these persons carry such an industry or trade."
The treaty became international law in 1919 when it was incorporated into the Treaty of Versailles. The role of the commission was passed to the League of Nations, and all signatory nations agreed to prohibit the import, sale, distribution, export, and use of all narcotic drugs, except for medical and scientific purposes.
=== Prohibition ===
In the UK the Defence of the Realm Act 1914, passed at the onset of the First World War, gave the government wide-ranging powers to requisition the property and to criminalize specific activities. A moral panic was whipped up by the press in 1916 over the alleged sale of drugs to the troops of the British Indian Army. With the temporary powers of DORA, the Army Council quickly banned the sale of all psychoactive drugs to troops, unless required for medical reasons. However, shifts in the public attitude towards drugs—they were beginning to be associated with prostitution, vice and immorality—led the government to pass further unprecedented laws, banning and criminalising the possession and dispensation of all narcotics, including opium and cocaine. After the war, this legislation was maintained and strengthened with the passing of the Dangerous Drugs Act 1920 (10 & 11 Geo. 5. c. 46). Home Office control was extended to include raw opium, morphine, cocaine, ecogonine and heroin.
Hardening of Canadian attitudes toward Chinese-Canadian opium users and fear of a spread of the drug into the white population led to the effective criminalization of opium for nonmedical use in Canada between 1908 and the mid-1920s.
The Mao Zedong government nearly eradicated both consumption and production of opium during the 1950s using social control and isolation. Ten million addicts were forced into compulsory treatment, dealers were executed, and opium-producing regions were planted with new crops. Remaining opium production shifted south of the Chinese border into the Golden Triangle region. The remnant opium trade primarily served Southeast Asia, but spread to American soldiers during the Vietnam War, with 20 percent of soldiers regarding themselves as addicted during the peak of the epidemic in 1971. In 2003, China was estimated to have four million regular drug users and one million registered drug addicts.
In the US, the Harrison Act was passed in 1914, and required sellers of opiates and cocaine to get a license. While originally intended to regulate the trade, it soon became a prohibitive law, eventually becoming legal precedent that any prescription for a narcotic given by a physician or pharmacist – even in the course of medical treatment for addiction – constituted conspiracy to violate the Harrison Act. In 1919, the Supreme Court ruled in Doremus that the Harrison Act was constitutional and in Webb that physicians could not prescribe narcotics solely for maintenance. In Jin Fuey Moy v. United States, the court upheld that it was a violation of the Harrison Act even if a physician provided prescription of a narcotic for an addict, and thus subject to criminal prosecution. This is also true of the later Marijuana Tax Act in 1937. Soon, however, licensing bodies did not issue licenses, effectively banning the drugs.
The American judicial system did not initially accept drug prohibition. Prosecutors argued that possessing drugs was a tax violation, as no legal licenses to sell drugs were in existence; hence, a person possessing drugs must have purchased them from an unlicensed source. After some wrangling, this was accepted as federal jurisdiction under the interstate commerce clause of the U.S. Constitution.
==== Alcohol prohibition ====
The prohibition of alcohol commenced in Finland in 1919 and in the United States in 1920. Because alcohol was the most popular recreational drug in these countries, reactions to its prohibition were far more negative than to the prohibition of other drugs, which were commonly associated with ethnic minorities, prostitution, and vice. Public pressure led to the repeal of alcohol prohibition in Finland in 1932, and in the United States in 1933. Residents of many provinces of Canada also experienced alcohol prohibition for similar periods in the first half of the 20th century.
In Sweden, a referendum in 1922 decided against an alcohol prohibition law (with 51% of the votes against and 49% for prohibition), but starting in 1914 (nationwide from 1917) and until 1955 Sweden employed an alcohol rationing system with personal liquor ration books ("motbok").
=== War on Drugs ===
In response to rising drug use among young people and the counterculture movement, government efforts to enforce prohibition were strengthened in many countries from the 1960s onward. Support at an international level for the prohibition of psychoactive drug use became a consistent feature of United States policy during both Republican and Democratic administrations, to such an extent that US support for foreign governments has often been contingent on their adherence to US drug policy. Major milestones in this campaign include the introduction of the Single Convention on Narcotic Drugs in 1961, the Convention on Psychotropic Substances in 1971 and the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances in 1988. A few developing countries where consumption of the prohibited substances has enjoyed longstanding cultural support, long resisted such outside pressure to pass legislation adhering to these conventions. Nepal only did so in 1976.
In 1972, United States President Richard Nixon announced the commencement of the so-called "War on Drugs". Later, President Reagan added the position of drug czar to the President's Executive Office. In 1973, New York introduced mandatory minimum sentences of 15 years to life imprisonment for possession of more than 113 grams (4 oz) of a so-called hard drug, called the Rockefeller drug laws after New York Governor and later Vice President Nelson Rockefeller. Similar laws were introduced across the United States.
California's broader 'three strikes and you're out' policy adopted in 1994 was the first mandatory sentencing policy to gain widespread publicity and was subsequently adopted in most United States jurisdictions. This policy mandates life imprisonment for a third criminal conviction of any felony offense. A similar 'three strikes' policy was introduced to the United Kingdom by the Conservative government in 1997. This legislation enacted a mandatory minimum sentence of seven years for those convicted for a third time of a drug trafficking offense involving a class A drug.
=== Calls for legalization, relegalization or decriminalization ===
The terms relegalization, legalization, legal regulations, or decriminalization are used with very different meanings by different authors, something that can be confusing when the claims are not specified. Here are some variants:
Sales of one or more drugs (e.g., marijuana) for personal use become legal, at least if sold in a certain way.
Sales of an extracts with a specific substance become legal sold in a certain way, for example on prescription.
Use or possession of small amounts for personal use do not lead to incarceration if it is the only crime, but it is still illegal; the court or the prosecutor can impose a fine. (In that sense, Sweden both legalized and supported drug prohibition simultaneously.)
Use or possession of small amounts for personal use do not lead to incarceration. The case is not treated in an ordinary court, but by a commission that may recommend treatment or sanctions including fines. (In that sense, Portugal both legalized and supported drug prohibitions).
There are efforts around the world to promote the relegalization and decriminalization of drugs. These policies are often supported by proponents of liberalism and libertarianism on the grounds of individual freedom, as well as by leftists who believe prohibition to be a method of suppression of the working class by the ruling class.
Prohibition of drugs is supported by proponents of conservatism as well various NGOs. A number of NGOs are aligned in support of drug prohibition as members of the World Federation Against Drugs. In the WFAD constitution, the "Declaration of the World Forum Against Drugs" (2008) advocates for "no other goal than a drug-free world", and states that a balanced policy of drug abuse prevention, education, treatment, law enforcement, research, and supply reduction provides the most effective platform to reduce drug abuse and its associated harms and calls on governments to consider demand reduction as one of their first priorities. It supports the UN drug conventions, the inclusion of cannabis as one of the "hard drugs", and the use of criminal sanctions "when appropriate" to deter drug use. It opposes legalization in any form, and harm reduction in general.
According to some critics, drug prohibition is responsible for enriching "organised criminal networks" while the hypothesis that the prohibition of drugs generates violence is consistent with research done over long time-series and cross-country facts.
In the United Kingdom, where the principal piece of drug prohibition legislation is the Misuse of Drugs Act 1971, criticism includes:
Drug classification: making a hash of it?, Fifth Report of Session 2005–06, House of Commons Science and Technology Committee, which said that the present system of drug classification is based on historical assumptions, not scientific assessment
Development of a rational scale to assess the harm of drugs of potential misuse, David Nutt, Leslie A. King, William Saulsbury, Colin Blakemore, The Lancet, 24 March 2007, said the act is "not fit for purpose" and "the exclusion of alcohol and tobacco from the Misuse of Drugs Act is, from a scientific perspective, arbitrary"
The Drug Equality Alliance (DEA) argue that the Government is administering the Act arbitrarily, contrary to its purpose, contrary to the original wishes of Parliament and therefore illegally. They are currently assisting and supporting several legal challenges to this alleged maladministration.
In February 2008 the then-president of Honduras, Manuel Zelaya, called on the world to legalize drugs, in order, he said, to prevent the majority of violent murders occurring in Honduras. Honduras is used by cocaine smugglers as a transiting point between Colombia and the US. Honduras, with a population of 7 million, suffers an average of 8–10 murders a day, with an estimated 70% being a result of this international drug trade. The same problem is occurring in Guatemala, El Salvador, Costa Rica and Mexico, according to Zelaya. In January 2012 Colombian President Juan Manuel Santos made a plea to the United States and Europe to start a global debate about legalizing drugs. This call was echoed by the Guatemalan President Otto Pérez Molina, who announced his desire to legalize drugs, saying "What I have done is put the issue back on the table."
In a report dealing with HIV in June 2014, the World Health Organization (WHO) of the UN called for the decriminalization of drugs particularly including injected ones. This conclusion put WHO at odds with broader long-standing UN policy favoring criminalization. Eight states of the United States (Alaska, California, Colorado, Maine, Massachusetts, Nevada, Oregon, and Washington), as well as the District of Columbia, have legalized the sale of marijuana for personal recreational use as of 2017, although recreational use remains illegal under U.S. federal law. The conflict between state and federal law is, as of 2018, unresolved.
Since Uruguay in 2014 and Canada in 2018 legalized cannabis, the debate has known a new turn internationally.
On March 14th, 2025, the United Nations Commission on Narcotic Drugs decided to create a panel of independent experts to rethink the global drug control regime.
== Drug prohibition laws ==
The following individual drugs, listed under their respective family groups (e.g., barbiturates, benzodiazepines, opiates), are the most frequently sought after by drug users and as such are prohibited or otherwise heavily regulated for use in many countries:
Among the barbiturates, pentobarbital (Nembutal), secobarbital (Seconal), and amobarbital (Amytal)
Among the benzodiazepines, temazepam (Restoril; Normison; Euhypnos), flunitrazepam (Rohypnol; Hypnor; Flunipam), and alprazolam (Xanax)
Cannabis products, e.g., marijuana, hashish, and hashish oil
Among the dissociatives, phencyclidine (PCP), and ketamine are the most sought after.
hallucinogens such as LSD, mescaline, peyote, and psilocybin
Empathogen-entactogen drugs like MDMA ("ecstasy")
Among the narcotics, it is opiates such as morphine and codeine, and opioids such as diacetylmorphine (Heroin), hydrocodone (Vicodin; Hycodan), oxycodone (Percocet; Oxycontin), hydromorphone (Dilaudid), and oxymorphone (Opana).
Sedatives such as GHB and methaqualone (Quaalude)
Stimulants such as cocaine, amphetamine (Adderall), dextroamphetamine (Dexedrine), methamphetamine (Desoxyn), methcathinone, and methylphenidate (Ritalin)
The regulation of the above drugs varies in many countries. Alcohol possession and consumption by adults is today widely banned only in Islamic countries and certain states of India. Although alcohol prohibition was eventually repealed in the countries that enacted it, there are, for example, still parts of the United States that do not allow alcohol sales, though alcohol possession may be legal (see dry counties). New Zealand has banned the importation of chewing tobacco as part of the Smoke-free Environments Act 1990. In some parts of the world, provisions are made for the use of traditional sacraments like ayahuasca, iboga, and peyote. In Gabon, iboga (tabernanthe iboga) has been declared a national treasure and is used in rites of the Bwiti religion. The active ingredient, ibogaine, is proposed as a treatment of opioid withdrawal and various substance use disorders.
In countries where alcohol and tobacco are legal, certain measures are frequently undertaken to discourage use of these drugs. For example, packages of alcohol and tobacco sometimes communicate warnings directed towards the consumer, communicating the potential risks of partaking in the use of the substance. These drugs also frequently have special sin taxes associated with the purchase thereof, in order to recoup the losses associated with public funding for the health problems the use causes in long-term users. Restrictions on advertising also exist in many countries, and often a state holds a monopoly on manufacture, distribution, marketing, and/or the sale of these drugs.
=== List of principal drug prohibition laws by jurisdiction (non-exhaustive) ===
Australia: Standard for the Uniform Scheduling of Medicines and Poisons
Bangladesh: Narcotics Substances Control Act, 2018
Belize: Misuse of Drugs Act (Belize)
Canada: Controlled Drugs and Substances Act
Estonia: Narcotic Drugs and Psychotropic Substances Act (Estonia)
Germany: Narcotic Drugs Act
India: Narcotic Drugs and Psychotropic Substances Act (India)
Netherlands: Opium Law
New Zealand: Misuse of Drugs Act 1975
Pakistan: Control of Narcotic Substances Act 1997
Philippines: Comprehensive Dangerous Drugs Act of 2002
Poland: Drug Abuse Prevention Act 2005
Portugal: Decree-Law 15/93
Ireland: Misuse of Drugs Act (Ireland)
South Africa: Drugs and Drug Trafficking Act 1992
Singapore: Misuse of Drugs Act (Singapore)
Sweden: Lag om kontroll av narkotika (SFS 1992:860)
Thailand: Psychotropic Substances Act (Thailand) and Narcotics Act
United Kingdom: Misuse of Drugs Act 1971 and Drugs Act 2005
United States: Controlled Substances Act
International: Single Convention on Narcotic Drugs
=== Legal dilemmas ===
The sentencing statutes in the United States Code that cover controlled substances are complicated. For example, a first-time offender convicted in a single proceeding for selling marijuana three times, and found to have carried a gun on him all three times (even if it were not used) is subject to a minimum sentence of 55 years in federal prison.
In Hallucinations: Behavior, Experience, and Theory (1975), senior US government researchers Louis Jolyon West and Ronald K. Siegel explain how drug prohibition can be used for selective social control:
The role of drugs in the exercise of political control is also coming under increasing discussion. Control can be through prohibition or supply. The total or even partial prohibition of drugs gives the government considerable leverage for other types of control. An example would be the selective application of drug laws ... against selected components of the population such as members of certain minority groups or political organizations.
Linguist Noam Chomsky argues that drug laws are currently, and have historically been, used by the state to oppress sections of society it opposes:
Very commonly substances are criminalized because they're associated with what's called the dangerous classes, poor people, or working people. So for example in England in the 19th century, there was a period when gin was criminalized and whiskey wasn't, because gin is what poor people drink.
=== Legal highs and prohibition ===
In 2013 the European Monitoring Centre for Drugs and Drug Addiction reported that there are 280 new legal drugs, known as "legal highs", available in Europe. One of the best known, mephedrone, was banned in the United Kingdom in 2010. On November 24, 2010, the U.S. Drug Enforcement Administration announced it would use emergency powers to ban many synthetic cannabinoids within a month. An estimated 73 new psychoactive synthetic drugs appeared on the UK market in 2012. The response of the Home Office has been to create a temporary class drug order which bans the manufacture, import, and supply (but not the possession) of named substances.
=== Corruption ===
In certain countries, there is concern that campaigns against drugs and organized crime are a cover for corrupt officials tied to drug trafficking themselves. In the United States, Federal Bureau of Narcotics chief Harry Anslinger's opponents accused him of taking bribes from the Mafia to enact prohibition and create a black market for alcohol. More recently in the Philippines, one death squad hitman told author Niko Vorobyov that he was being paid by military officers to eliminate those drug dealers who failed to pay a 'tax'. Under President Rodrigo Duterte, the Philippines has waged a bloody war against drugs that may have resulted in up to 29,000 extrajudicial killings.
When it comes to social control with cannabis, there are different aspects to consider. Not only do we assess legislative leaders and the way they vote on cannabis, but we also must consider the federal regulations and taxation that contribute to social controls. For instance, according to a report on the U.S. customs and border protections, the American industry, although banned the main usage of marijuana, was still using products similar such as hemp seeds, oils etc. leading to the previously discussed marijuana tax act.
The Tax act provisions required importers to register and pay an annual tax of $24 and receive an official stamp. Stamps for Products were then affixed to each original order form and recorded by the state revenue collector. Then, a customs collector was to maintain the custody of imported marijuana at entry ports until required documents were received, reviewed and approved.Shipments were subject to searches, seizures and forfeitures if any provisions of the law were not met. Violations would result in fines of no more than $2000 or potential imprisonment for up to 5 years. Oftentimes, this created opportunity for corruption, stolen imports that would later lead to smuggling, oftentimes by state officials and tight knit elitists.
== Penalties ==
=== United States ===
Drug possession is the crime of having one or more illegal drugs in one's possession, either for personal use, distribution, sale or otherwise. Illegal drugs fall into different categories and sentences vary depending on the amount, type of drug, circumstances, and jurisdiction. In the U.S., the penalty for illegal drug possession and sale can vary from a small fine to a prison sentence. In some states, marijuana possession is considered to be a petty offense, with the penalty being comparable to that of a speeding violation. In some municipalities, possessing a small quantity of marijuana in one's own home is not punishable at all. Generally, however, drug possession is an arrestable offense, although first-time offenders rarely serve jail time. Federal law makes even possession of "soft drugs", such as cannabis, illegal, though some local governments have laws contradicting federal laws.
In the U.S., the War on Drugs is thought to be contributing to a prison overcrowding problem. In 1996, 59.6% of prisoners were drug-related criminals. The U.S. population grew by about +25% from 1980 to 2000. In that same 20 year time period, the U.S. prison population tripled, making the U.S. the world leader in both percentage and absolute number of citizens incarcerated. The United States has 5% of the world's population, but 25% of the prisoners.
About 90% of United States prisoners are incarcerated in state jails. In 2016, about 572,000, over 44%, of the 1.3 million people in these state jails, were serving time for drug offenses. 728,000 were incarcerated for violent offenses.
The data from Federal Bureau of Prisons online statistics page states that 45.9% of prisoners were incarcerated for drug offenses, as of December 2021.
=== European Union ===
In 2004, the Council of the European Union adopted a framework decision harmonizing the minimum penal provisions for illicit drug-related activities. In particular, article 2(9) stipulates that activities may be exempt from the minimum provisions "when it is committed by its perpetrators exclusively for their own personal consumption as defined by national law." This was made, in particular, to accommodate more liberal national systems such as the Dutch coffee shops (see below) or the Spanish Cannabis Social Clubs.
==== The Netherlands ====
In the Netherlands, cannabis and other "soft" drugs are decriminalised in small quantities. The Dutch government treats the problem as more of a public health issue than a criminal issue. Contrary to popular belief, cannabis is still technically illegal. Coffee shops that sell cannabis to people 18 or above are tolerated, and pay taxes like any other business for their cannabis and hashish sales, although distribution is a grey area that the authorities would rather not go into as it is not decriminalised. Many "coffee shops" are found in Amsterdam and cater mainly to the large tourist trade; the local consumption rate is far lower than in the US.
The administrative bodies responsible for enforcing the drug policies include the Ministry of Health, Welfare and Sport, the Ministry of Justice, the Ministry of the Interior and Kingdom Relations, and the Ministry of Finance. Local authorities also shape local policy, within the national framework.
When compared to other countries, Dutch drug consumption falls in the European average at six per cent regular use (twenty-one per cent at some point in life) and considerably lower than the Anglo-Saxon countries headed by the United States with an eight per cent recurring use (thirty-four at some point in life).
=== Australia ===
A Nielsen poll in 2012 found that only 27% of voters favoured decriminalisation. Australia has steep penalties for growing and using drugs even for personal use. with Western Australia having the toughest laws. There is an associated anti-drug culture amongst a significant number of Australians. Law enforcement targets drugs, particularly in the party scene. In 2012, crime statistics in Victoria revealed that police were increasingly arresting users rather than dealers, and the Liberal government banned the sale of bongs that year.
=== Indonesia ===
Indonesia carries a maximum penalty of death for drug dealing, and a maximum of 15 years prison for drug use. In 2004, Australian citizen Schapelle Corby was convicted of smuggling 4.4 kilograms of cannabis into Bali, a crime that carried a maximum penalty of death. Her trial reached the verdict of guilty with a punishment of 20 years imprisonment. Corby claimed to be an unwitting drug mule. Australian citizens known as the "Bali Nine" were caught smuggling heroin. Two of the nine, Andrew Chan and Myuran Sukumaran, were executed April 29, 2015 along with six other foreign nationals. In August 2005, Australian model Michelle Leslie was arrested with two ecstasy pills. She pleaded guilty to possession and in November 2005 was sentenced to 3 months imprisonment, which she was deemed to have already served, and was released from prison immediately upon her admission of guilt on the charge of possession.
At the 1961 Single Convention on Narcotic Drugs, Indonesia, along with India, Turkey, Pakistan and some South American countries opposed the criminalisation of drugs.
=== Republic of China (Taiwan) ===
Taiwan carries a maximum penalty of death for drug trafficking, while smoking tobacco and wine are classified as legal entertainment drug. The Department of Health is in charge of drug prohibition.
== Cost ==
In 2020, the direct cost of drug prohibition to United States taxpayers was estimated at over $40 billion annually. Prohibition can increase organized crime, government corruption, and mass incarceration via the trade in illegal drugs, while racial and gender disparities in enforcement are evident.
Although drug prohibition is often portrayed by proponents as a measure to improve public health, evidence is lacking. In 2016, the Johns Hopkins–Lancet Commission concluded that the "harms of prohibition far outweigh the benefits", citing increased risk of overdoses and HIV infection and detrimental effects on the social determinants of health. Some proponents argue that drug prohibition's effect on suppressing usage rates (although the magnitude of this effect is unknown) outweighs the negative effects of prohibition.
Alternative approaches to prohibition include drug legalization, drug decriminalization, and government monopoly.
== See also ==
Alcohol law
Arguments for and against drug prohibition
Chasing the Scream
Drug liberalization
Demand reduction
Drug policy of the Soviet Union
Harm reduction
List of anti-cannabis organizations
Medellín Cartel
Mexican drug war
Puerto Rican drug war
Prohibitionism
Tobacco control
War on Drugs
US specific:
Allegations of CIA drug trafficking
School district drug policies
Drug Free America Foundation
Drug Policy Alliance
DrugWarRant
Gary Webb
Marijuana Policy Project
National Organization for the Reform of Marijuana Laws
Students for Sensible Drug Policy
Woman's Christian Temperance Union
== References ==
== Further reading ==
== External links ==
Making Contact: The Mission to End Prohibition. Radio piece featuring LEAP founder and former narcotics officer Jack Cole, and Drug Policy Alliance founder Ethan Nadelmann
EMCDDA – Decriminalisation in Europe? Recent developments in legal approaches to drug use Archived January 12, 2007, at the Wayback Machine.
10 Downing Street's Strategy Unit Drugs Report
War on drugs Archived April 30, 2011, at the Wayback Machine Part I: Winners, documentary (50 min) explaining 'War on Drugs' by Tegenlicht of VPRO Dutch television. After short introduction in Dutch (1 min), English spoken. Broadband internet needed.
War on drugs Archived April 30, 2011, at the Wayback Machine Part II: Losers, documentary (50 min) showing downside of the 'War on Drugs' by Tegenlicht of VPRO Dutch television. After short introduction in Dutch (1 min), English spoken. Broadband internet needed.
After the War on Drugs: Options for Control (Report)
The Drug War as a Socialist Enterprise by Milton Friedman
Free from the Nightmare of Prohibition Archived February 23, 2006, at the Wayback Machine by Harry Browne
Prohibition news page – Alcohol and Drugs History Society
Drugs and conservatives should go together | Wikipedia/Drug_prohibition_law |
The Drug Enforcement Administration (DEA) is a United States federal law enforcement agency under the U.S. Department of Justice tasked with combating illicit drug trafficking and distribution within the U.S. It is the lead agency for domestic enforcement of the Controlled Substances Act, sharing concurrent jurisdiction with the Federal Bureau of Investigation and U.S. Customs and Border Protection. The DEA is responsible for coordinating and pursuing U.S. drug investigations both domestically and internationally.
It was established in 1973 as part of the U.S. government's war on drugs. The DEA has an intelligence unit that is also a member of the U.S. Intelligence Community. While the unit is part of the DEA chain-of-command, it also reports to the director of national intelligence. The DEA has been criticized for scheduling drugs that have medicinal uses, and for focusing on operations that allow it to seize money rather than those involving drugs that cause more harm.
== History and mandate ==
The Drug Enforcement Administration was established on July 1, 1973, by Reorganization Plan No. 2 of 1973, signed by President Richard Nixon on July 28. It proposed the creation of a single federal agency to enforce the federal drug laws as well as consolidate and coordinate the government's drug control activities. Congress accepted the proposal, as they were concerned with the growing availability of drugs. As a result, the Bureau of Narcotics and Dangerous Drugs (BNDD), the Office of Drug Abuse Law Enforcement (ODALE); approximately 600 Special Agents of the Bureau of Customs, Customs Agency Service, and other federal offices merged to create the DEA.
The DEA is the primary federal agency charged with implementing and enforcing the Controlled Substances Act (CSA), which is Title II of a larger Federal Act called the Comprehensive Drug Abuse Prevention and Control Act of 1970. The DEA is responsible for drugs listed in the CSA's five drug Schedules, categories that rank drugs by their potential for harm, and whether they have a medical use. The CSA seeks to ensure legitimate access to controlled pharmaceuticals, while preventing illicit use of controlled drugs. To these ends, the DEA implements two intersecting legal schemes created by the CSA, registration provisions for entities involved in legal activities, violations of which are not usually criminal offenses, and trafficking provisions for illegal activities, violations of which are criminal offenses.
From the early 1970s, DEA headquarters was located at 1405 I ("Eye") Street NW in downtown Washington, D.C. With the overall growth of the agency in the 1980s (owing to the increased emphasis on federal drug law enforcement efforts) and concurrent growth in the headquarters staff, the DEA began to search for a new headquarters location; locations in Arkansas, Mississippi and various abandoned military bases around the United States were considered. However, then–attorney general Edwin Meese determined that the headquarters had to be located close to the attorney general's office. Thus, in 1989, the headquarters relocated to 600–700 Army-Navy Drive in the Pentagon City area of Arlington County, Virginia, near the eponymous Metro station.
On April 19, 1995, Timothy McVeigh carried out a terrorist attack on the Alfred P. Murrah Federal Building in Oklahoma City. He was targeting regional offices for the Federal Bureau of Investigation (FBI), Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) and DEA, all of which had carried out raids that he viewed as unjustified intrusions on the rights of the people. This attack caused the deaths of two DEA employees, one task force member and two contractors in the Oklahoma City bombing. Subsequently, the DEA headquarters complex was classified as a Level IV installation under United States federal building security standards, meaning it was to be considered a high-risk law enforcement target for terrorists. Security measures include hydraulic steel roadplates to enforce standoff distance from the building, metal detectors and guard stations.
In February 2003, the DEA established a Digital Evidence Laboratory within its Office of Forensic Sciences.
== Organization ==
The DEA is headed by an administrator of the Drug Enforcement Administration appointed by the president of the United States and confirmed by the U.S. Senate. The Administrator reports to the attorney general through the deputy attorney general. The administrator is assisted by a deputy administrator, the chief of operations, the chief inspector, and three assistant administrators (for the Operations Support, Intelligence, and Human Resources divisions). Other senior staff includes the chief financial officer and the chief counsel. The administrator and deputy administrator are the only presidentially appointed personnel in the DEA; all other DEA officials are career government employees. DEA's headquarters is located in Arlington County, Virginia, across from the Pentagon. It maintains its own DEA Academy located on the Marine Corps Base Quantico at Quantico, Virginia, alongside the FBI Academy. As of 2024, it maintains 241 domestic offices in 23 divisions, and 93 foreign offices in 69 countries. With a budget exceeding $3 billion, DEA employs 10,169 people, including 4,924 special agents and 800 intelligence analysts.
c. 2015 its headquarters and the DEA Museum were in 503,776 square feet (46,802.3 m2) in Lincoln Place, a rented office building in Pentagon City in Arlington County, Virginia. In September 2018 this lease was scheduled to end. The General Services Administration (GSA), circa 2015, was checking to see where in Northern Virginia the DEA could be headquartered. In 2018 the government of the United States extended the lease at Lincoln Place, now to expire circa 2033. The DEA administration favored retaining the original location.
=== Structure ===
Administrator
Deputy Administrator
Human Resource Division
Career Board
Board of Professional Conduct
Office of Training
Operations Division
Aviation Division
Office of Operations Management
Special Operations Division
Office of Diversion Control
Office of Global Enforcement
Office of Financial Operations
Intelligence Division
Office of National Security Intelligence (ONSI)
Office of Strategic Intelligence
Office of Special Intelligence
El Paso Intelligence Center
OCDETF Fusion Center
Financial Management Division
Office of Acquisition and Relocation Management
Office of Finance
Office of Resource Management
Operational Support Division
Office of Administration
Office of Information System
Office of Forensic Science
Office of Investigative Technology
Inspection Division
Office of Inspections
Office of Professional Responsibility
Office of Security Programs
Field Divisions and Offices
=== Special agents ===
As of 2017, there were 4,650 special agents employed by the Drug Enforcement Administration. DEA agents' starting salary is $49,746–$55,483. After four years, the salary rises to above $92,592. This figure doesn’t include Cost of living allowance (COLA) or LEAP which rated at 25% of base pay including COLA. Special Agents at the 13 step 5 level in high cost of living areas of the United States make near the federal pay cap of $191,000.
After receiving a conditional offer of employment, recruits must then complete an 18-week rigorous training which includes lessons in firearms proficiency (including basic marksmanship), weapons safety, tactical shooting, and deadly-force decision training. To graduate, students must maintain an academic average of 80 percent on academic examinations, pass the firearms qualification test, successfully demonstrate leadership and sound decision-making in practical scenarios, and pass rigorous physical-task tests. Upon graduation, recruits earn the title of DEA Special Agent.
Because the DEA is responsible for enforcing the Controlled Substances Act, it excludes from consideration job applicants who use or have a recent history of using narcotics or illicit drugs. As of June 27, 2024, DEA applicants cannot have used cannabis or marijuana within three years of submitting their application and cannot have used any other narcotic substance within seven years of applying, although allowances are made for the use of marijuana prior to an applicant's 18th birthday. Background investigations usually include a polygraph test for special-agent, diversion-investigator, and intelligence research specialist positions.
The DEA's relatively firm stance on personal drug use contrasts with those of the Central Intelligence Agency and the Federal Bureau of Investigation, which in 2023 considered further relaxing their eligibility guidelines so as to combat dwindling recruitment rates.
=== Aviation Division ===
The DEA Aviation Division or Office of Aviation Operations (OA) (formerly Aviation Section) is an airborne division based in Perot Field Fort Worth Alliance Airport, Texas. The current OA fleet consists of 106 aircraft and 124 DEA pilots.
The DEA shares a communications system with the Department of Defense for communication with state and regional enforcement independent of the Department of Justice and police information systems and is coordinated by an information command center called the El Paso Intelligence Center (EPIC) near El Paso, Texas.
=== Special Response Teams ===
Rapid Response Teams (RRT), previously known as Foreign-Deployed Advisory and Support Teams (FAST), were decommissioned by DEA acting administrator Chuck Rosenburg in March 2017 via memorandum. A need for domestic high-risk service teams led to the hybrid creation of specialized tactical units residing within various geographical regions throughout the United States.
DEA officially created and standardized its Special Response Team (SRT) program in 2016. The SRT was designed as a stop-gap between tactical operations conducted by field agents and those necessitating specialized tactics as a result of elevated risks. SRT operators are highly trained in various weapons systems and entry tactics/maneuvers. Because of the clandestine nature of the DEA mission, SRT training protocols and activation requirements are highly sensitive and not available to the public. Some of the SRT missions consist of high-risk arrests, vehicle assaults, air assault/infiltration, specialized surveillance, custody of high-profile individuals, dignitary and witness protection, tactical surveillance and interdiction, advanced breaching, tactical training to other police units, and urban and rural fugitive searches. Covertly located throughout the nation, DEA SRT teams are available to respond to practically any CONUS geographical area with little to no preparation or notification. The DEA SRT has been involved in several high-profile operations in recent years, however, DEA involvement is often not publicized due to operational and intelligence considerations. Considered one of the most covert outfits in federal law enforcement, very little is known about DEA SRT capabilities and its operator selection process.
In the past, DEA had other tactical teams like the High-risk Entry Apprehension Teams (HEAT) in some Field Divisions, and Operation Snowcap Teams (predecessor of FAST). The teams administered by the Mobile Enforcement Section, the Mobile Enforcement Teams (MET), and Regional Enforcement Teams (RET), were mobile investigative units intended to deploy resources to state and local agencies (MET) or DEA Field Divisions (RET) in need of assistance with a particular investigation or trafficking group. These programs ended in the early 2000s.
=== Special Operations Division ===
The DEA Special Operations Division (SOD) is a division within the DEA, which forwards information from wiretaps, intercepts, and databases from various sources to federal agents and local law enforcement officials. The SOD came under scrutiny following the 2010s global surveillance disclosures.
=== Domestic Cannabis Eradication/Suppression Program ===
The Domestic Cannabis Eradication/Suppression Program (DCE/SP) began funding eradication programs in Hawaii and California in 1979. The program rapidly expanded to include programs in 25 states by 1982. By 1985, all 50 states were participating in the DCE/SP. In 2015, the DCE/SP was responsible for the eradication of 3,932,201 cultivated outdoor cannabis plants and 325,019 indoor plants for a total of 4,257,220 marijuana plants. In addition, the DCE/SP accounted for 6,278 arrests and the seizure in excess of $29.7 million of cultivator assets.
In 2014, the DEA spent $73,000 to eradicate marijuana plants in Utah, though they did not find a single marijuana plant. Federal documents obtained by journalist Drew Atkins detail the DEA's continuing efforts to spend upwards of $14 million per year to completely eradicate marijuana within the United States despite the government funding allocation reports showing that the Marijuana Eradication Program often leads to the discovery of no marijuana plants. This prompted twelve members of Congress to push for the elimination of the program and use the money instead to fund domestic-violence prevention and deficit-reduction programs.
== Budget ==
In 2018, the DEA budget was $2.086 billion. $445 million was spent on international enforcement and $1.627 billion was spent on domestic enforcement.
Breaking foreign and domestic sources of supply ($1.0149 billion) via domestic cannabis eradication/suppression; domestic enforcement; research, engineering, and technical operations; the Foreign Cooperative Investigations Program; intelligence operations (financial intelligence, operational intelligence, strategic intelligence, and the El Paso Intelligence Center); and drug and chemical diversion control.
Reduction of drug-related crime and violence ($181.8 million) funding state and local teams and mobile enforcement teams.
Demand reduction ($3.3 million) via anti-legalization education, training for law enforcement personnel, youth programs, support for community-based coalitions, and sports drug awareness programs.
== Firearms ==
DEA agents' primary service weapons are the Glock 17 and Glock 19, Remington 870 12-gauge shotgun, and Rock River Arms LAR-15 semi-automatic carbine in 5.56×45mm NATO. Agents may also qualify to carry a firearm listed on an authorized carry list maintained and updated by the Firearms Training Unit (FTU), Quantico, Virginia.
Special Agents may qualify with their own personally-owned handguns, rifle, and shotgun, and certain handguns are allowed to be used with permission from the FTU. Agents are required to attend tactical and firearms proficiency training quarterly, and to qualify with their handguns twice per year. The DEA has one of the most challenging handgun qualification courses in all of the federal law enforcement. Failure to achieve a passing qualification score is the reason for most Academy dismissals and special agents in the field may have their authority to carry a firearm revoked for failure to qualify.
Basic Agent Trainees (BATs) who fail the initial pistol qualification course of fire are placed in a remedial program to receive additional training. In remedial training, BATs receive five extra two-hour range sessions, for a total of 10 more hours of live fire training on their issued sidearm, to further aid them in helping pass the pistol qualification. After passing their pistol qualification, Basic Agent Trainees move on to receive formal training on the DEA's standard-issue long guns and will continue to frequently shoot the agency-issued sidearms that they have already qualified on. In all, BATs receive a total of 32 firearms training sessions, when combining classroom instruction, gear issue, and pistol, rifle, and shotgun live fire training at the DEA Academy. They will shoot the qualification courses for all three weapons systems during their initial training but must pass their final qualification attempts only on their Glock pistols to become a Special Agent.
Agents are trained to use shoulder-fired weapons, such as the Rock River LAR-15, adopted in 2004, and the LWRC M6A2, the standard carbine of DEA. The Colt 9mm SMG was previously issued, but no longer in service. Agents are required to complete a two-day (16-hour) proficiency course to carry a shoulder weapon on enforcement operations. They may carry a Rock River LAR-15 or LWRC carbine as authorized, personally-owned weapons, provided they meet the same training and proficiency standards.
== Impact on the drug trade ==
In 2005, the DEA seized a reported $1.4 billion in drug trade related assets and $477 million worth of drugs. According to the White House's Office of Drug Control Policy, the total value of all of the drugs sold in the U.S. is as much as $64 billion a year, giving the DEA an efficiency rate of less than 1% at intercepting the flow of drugs into and within the United States. Critics of the DEA (including recipient of the Nobel Memorial Prize in Economic Sciences, Milton Friedman, prior to his death a member of Law Enforcement Against Prohibition) point out that demand for illegal drugs is inelastic; the people who are buying drugs will continue to buy them with little regard to price, often turning to crime to support expensive drug habits when the drug prices rise. One recent study by the DEA showed that the price of cocaine and methamphetamine is the highest it has ever been while the quality of both is at its lowest point ever. This is contrary to a collection of data done by the Office of National Drug Control Policy, which states that purity of street drugs has increased, while price has decreased. In contrast to the statistics presented by the DEA, the United States Department of Justice released data in 2003 showing that purity of methamphetamine was on the rise.
=== Registration and licensing ===
The DEA has a registration system in place which authorizes anyone to manufacture, import, export, and distribute by filing DEA form 225 Archived November 8, 2015, at the Wayback Machine along with medical professionals, researchers and manufacturers access to "Schedule I" drugs, as well as Schedules 2, 3, 4 and 5. Authorized registrants apply for and, if granted, receive a "DEA number". An entity that has been issued a DEA number is authorized to manufacture (drug companies), distribute research, prescribe (doctors, pharmacists, nurse practitioners and physician assistants, etc.), or dispense (pharmacy) a controlled substance.
=== Diversion control system ===
Many problems associated with substance use disorders are the result of legitimately manufactured controlled substances being diverted from their lawful purpose into the illicit drug traffic. Many of the analgesics, depressants and stimulants manufactured for legitimate medical use can often carry the potential for addiction. Therefore, those scheduled substances have been brought under legal control for prevention and population safety. The goal of controls is to ensure that these "controlled substances" are readily available for medical use while preventing their distribution for illicit distribution and non-medical use. This can be a difficult task, sometimes providing difficulty for legitimate patients and healthcare providers while circumventing illegal trade and consumption of scheduled drugs.
Under federal law, all businesses which manufacture or distribute controlled drugs, all health professionals entitled to dispense, administer or prescribe them, and all pharmacies entitled to fill prescriptions must register with the DEA. Registrants must comply with a series of regulatory requirements relating to drug security, records accountability, and adherence to standards.
All of these investigations are conducted by Diversion Investigators (DIs). DIs conduct investigations to uncover and investigate suspected sources of diversion and take appropriate civil and administrative actions. Prescription Database Management Programs (PDMP) aid and facilitate investigation and surveillance.
=== Fentanyl overdose crisis ===
In 2019 and 2020, record overdoses from illicit fentanyl tablets or as a deadly adulterant in heroin have ravaged North America. An estimated 19,416 individuals died of a drug overdose in the United States in the first 3 months of 2020 compared with 16,682 in the same 3-month period in 2019; this trend was fueled by synthetic opioids (especially illicitly manufactured fentanyl and analogs). Furthermore, between May 2020 and April 2021, the estimated number of drug overdose deaths in the United States exceeded 100,000 over this time period, with 64.0% of deaths involving synthetic opioids other than methadone (the same illicitly manufactured fentanyls and analogs). In contrast, Europe has seen a decrease from heroin overdoses, and a practical absence of illicit, synthetic opioids.
Fentanyl, originally developed in the 1970s by Janssen Pharmaceutica, is a potent anesthetic primarily used in hospital or hospice settings. In Europe, heroin is mainly supplied from Western Asia (from Afghanistan and neighboring countries), and less likely to be contaminated with fentanyl. In North America, there are now fewer deaths involving heroin than either meth or cocaine, a striking change that has taken place over the last two years as heroin has all but disappeared from some regions. Due to the absence of heroin from Asian sources, fentanyl-laced heroin powder or tablets have filled that void.
In October 2021, the US reported another record in fentanyl deaths, as federal agencies were unable to stem the tide of illicit, synthetic drugs entering the US. Originally, introduced to replace much of the white powder heroin in the Eastern United States, the drug continues to move further west. Between July 2019–December 2020, illicitly manufactured fentanyl involved deaths increased sharply in midwestern (33.1%), southern (64.7%), and western (93.9%) jurisdictions.
=== MDMA DEA scheduling overturn ===
In 1985 MDMA and its analogues were under review by the American government as a drug with a potential for addiction. During this time, several public hearings on the new drug were held by the DEA. Based on all of the evidence and facts presented at the time, the DEA's administrative law judge did not see MDMA and its analogues as being of large concern and recommended that they be placed in Schedule III. The DEA administrator, expressing concern for addictive potential, overruled the recommendation and ruled that MDMA be put in Schedule I, the Controlled Substances Act's most restrictive category.
== Rank structure ==
The following is a listing of the rank structure found within the DEA (in ascending order):
Agents
Agent Trainee
Special Agent
Senior Special Agent
Supervising Special Agent
Assistant Special Agent in Charge (ASAC)
Special Agent in Charge (SAC)
Management
Assistant Administrator
Associate Deputy Administrator
Deputy Administrator
Principal Deputy Administrator
Chief of Staff
Administrator
== Line of duty deaths ==
54 DEA agents have been killed in the line of duty.
== Criticism and controversies ==
The DEA has been criticized for placing highly restrictive schedules on a few drugs that researchers in the fields of pharmacology and medicine regard as having medical uses. Critics assert that some such decisions are motivated primarily by political factors stemming from the U.S. government's war on drugs and that many benefits of such substances remain unrecognized due to the difficulty of conducting scientific research. A counterpoint to that criticism is that under the Controlled Substances Act it is the Department of Health and Human Services (through the Food and Drug Administration and the National Institute on Drug Abuse), not the DEA, which has the legal responsibility to make scientific and medical determinations with respect to drug scheduling; no drug can be scheduled if the secretary of health and human services recommends against it on a scientific or medical basis, and no drug can be placed in the most restrictive schedule (Schedule I) if DHHS finds that the drug has an accepted medical use. Jon Gettman's essay Science and the End of Marijuana Prohibition describes the DEA as "a fall guy to deflect responsibility from the key decision-makers" and opines, "HHS calls the shots when it comes to marijuana prohibition, and the cops at DEA and the general over at ONDCP take the heat."
The DEA is also criticized for focusing on the operations from which it can seize the most money, namely the organized cross-border trafficking of marijuana. Some individuals contemplating the nature of the DEA's charter advise that, based on danger, the DEA should be most focused on cocaine. Others suggest that, based on opiate popularity, the DEA should focus much more on prescription opiates used recreationally, which critics contend comes first before users switch to heroin.
Practitioners who legally prescribe medicine however must possess a valid DEA license. According to federal law, the budget of the DEA Diversion Control Program is to be paid by these license fees. In 1984 a three-year license cost $25. In 2009 the fee for a three-year license was $551. Some have likened this approach to license fees unreasonable, "like making pilot licenses support the entire Federal Aviation Administration (FAA) budget." The renewal fee for 2020 as of October 1, 2020, is $888 for a three-year license.
In 2005, the DEA estimated that it had over 4,000 informants without which they "could not effectively enforce the controlled substances laws of the United States." To gather information, agents permitted their informants to buy and sell drugs, engage in Medicaid fraud rings, and other illicit acts. Despite this, the DEA claims that they are "in compliance" with the rules for using informants to gather information about illicit activities.
=== Costs ===
The total budget of the DEA from 1972 to 2014, according to the agency website, was $50.6 billion. The agency had 11,055 employees in 2014. For the year 2014 the average cost per arrest made was $97,325.
=== Civil liberties ===
Others, such as former Republican congressman Ron Paul, the Cato Institute, The Libertarian Party and the Drug Policy Alliance criticize the very existence of the DEA and the war on drugs as both hostile, and contrary, to the concept of civil liberties by arguing that anybody should be free to put any substance they choose into their own bodies for any reason, particularly when legal drugs such as alcohol, tobacco and prescription drugs are also open to addiction, and that any harm caused by a drug user or addict to the general public is a case of conflicting civil rights. Recurrently, billions of dollars are spent yearly, focusing largely on criminal law and demand reduction campaigns, which has resulted in the imprisonment of thousands of U.S. citizens. Demand for recreational drugs is somewhat static as the market for most illegal drugs has been saturated, forcing the cartels to expand their market to Europe and other areas than the United States. United States federal law registers cannabis as a Schedule I drug.
=== Incarceration of Daniel Chong ===
In April 2012 in San Diego, California, DEA agents detained a student, Daniel Chong, and left him locked in a holding room for five days. The cell contained no food, water or bathroom facilities. When he was found, he had to be hospitalized for several days for a variety of medical problems. The incident touched off a national furor, resulting in several investigations. The incident has been described as a "Kafkaesque nightmare," a "debacle," and "one of the worst cases of its kind." Chong subsequently sued the DEA; the government settled the suit for $4.1 million.
=== Department of Justice Smart on Crime Program ===
On August 12, 2013, at the American Bar Association's House of Delegates meeting, Attorney General Eric Holder announced the "Smart on Crime" program, which is "a sweeping initiative by the Justice Department that in effect renounces several decades of tough-on-crime anti-drug legislation and policies." Holder said the program "will encourage U.S. attorneys to charge defendants only with crimes "for which the accompanying sentences are better suited to their individual conduct, rather than excessive prison terms more appropriate for violent criminals or drug kingpins..." Running through Holder's statements, the increasing economic burden of over-incarceration was stressed. As of August 2013, the Smart on Crime program is not a legislative initiative but an effort "limited to the DOJ's policy parameters."
=== International events ===
David Coleman Headley (born Daood Sayed Gilani, June 30, 1960) who was working as an informant for the U.S. Drug Enforcement Administration (DEA) simultaneously made periodic trips to Pakistan for LeT training and was one of the main conspirators in the 2008 Mumbai attacks.
On January 24, 2013, Headley, then 52 years old, was sentenced by U.S. district judge Harry Leinenweber of the United States District Court for the Northern District of Illinois in Chicago to 35 years in prison for his part in the 2008 Mumbai attacks, in which at least 164 victims (civilians and security personnel) and nine attackers were killed. Among the dead were 28 foreign nationals from 10 countries. One attacker was captured. The bodies of many of the dead hostages showed signs of torture or disfigurement. A number of those killed were notable figures in business, media, and security services.
The DEA was accused in 2005 by the Venezuelan government of collaborating with drug traffickers, after which President Hugo Chávez decided to end any collaboration with the agency. In 2007, after the U.S. State Department criticized Venezuela in its annual report on drug trafficking, the Venezuelan Minister of Justice reiterated the accusations: "A large quantity of drug shipments left the country through that organization. We were in the presence of a new drug cartel."
In his 1996 series of articles and subsequent 1999 book, both titled Dark Alliance, journalist Gary Webb asserts that the DEA helped harbor Nicaraguan drug traffickers. Notably, they allowed Oscar Danilo Blandón political asylum in the USA despite knowledge of his cocaine-trafficking organization.
The government of Bolivia has also taken similar steps to ban the DEA from operating in the country. In September 2008, Bolivia drastically reduced diplomatic ties with the United States, withdrawing its ambassador from the US and expelling the US ambassador from Bolivia. This occurred soon after Bolivian president Evo Morales expelled all DEA agents from the country due to a revolt in the traditional coca-growing Chapare Province. The Bolivian government claimed that it could not protect the agents, and Morales further accused the agency of helping incite the violence, which claimed 30 lives. National agencies were to take over control of drug management. Three years later, Bolivia and the US began to restore full diplomatic ties. However, Morales maintained that the DEA would remain unwelcome in the country, characterising it as an affront to Bolivia's "dignity and sovereignty".
In the Netherlands, both the Dutch government and the DEA have been criticized for violations of Dutch sovereignty in drug investigations. According to Peter R. de Vries, a Dutch journalist present at the 2005 trial of Henk Orlando Rommy, the DEA has admitted to activities on Dutch soil. Earlier, then Minister of Justice Piet Hein Donner, had denied to the Dutch parliament that he had given permission to the DEA for any such activities, which would have been a requirement by Dutch law in order to allow foreign agents to act within the territory.
The DEA conducted a covert operation over several years in which undercover operatives were sent to Venezuela to build drug-trafficking cases against Venezuela's leadership, including Nicholas Maduro. The plan was part of "Operation Money Badger", which the DEA and prosecutors in Miami created in 2013. It potentially breached Venezuelan and international law and therefore required the approval of the Sensitive Activity Review Committee, a secretive panel of senior State and Justice Department officials that oversees the most sensitive DEA cases involving tricky ethical, legal or foreign policy considerations.
Following the Colombian peace process, which brought an end to the Colombian conflict between the Colombian government and the Revolutionary Armed Forces of Colombia (FARC–EP), the Special Jurisdiction for Peace found that the DEA had plotted with Colombian Attorney General Néstor Humberto Martínez to fabricate drug trafficking charges against Jesús Santrich, in a bid to jeopardize the peace agreement by inciting the FARC to take up arms again.
=== Special Operations Division fabricated evidence trails ===
In 2013, Reuters published a report about the DEA's Special Operations Division (SOD) stating that it conceals where an investigative trail about a suspect truly originates from and creates a parallel set of evidence given to prosecutors, judges, and defense lawyers. This DEA program mainly affects common criminals such as drug dealers. The concealment of evidence means the defendant is unaware of how his or her investigation began and will be unable to request a review of possible sources of exculpatory evidence. Exculpatory evidence may include biased witnesses, mistakes, or entrapment. Nancy Gertner, a former federal judge who had served from 1994 to 2011 and a Harvard Law School professor, stated that "It is one thing to create special rules for national security. Ordinary crime is entirely different. It sounds like they are phonying up investigations." Andrew O'Hehir of Salon wrote that "It's the first clear evidence that the “special rules” and disregard for constitutional law that have characterized the hunt for so-called terrorists have crept into the domestic criminal justice system on a significant scale."
=== Cannabis rescheduling ===
A 2014 report by the Multidisciplinary Association for Psychedelic Studies and the Drug Policy Alliance accuses the DEA of unfairly blocking the removal of cannabis from Schedule I. The report alleges that the methods employed by the DEA to achieve this include: delaying rescheduling petitions for years, overruling DEA administrative law judges, and systematically impeding scientific research. The DEA continues to refuse the removal of cannabis from Schedule I despite wide-scale acceptance of the substance among the medical community, including 76% of doctors, for the treatment of various diseases.
=== Domestic anti-drug advocacy ===
The DEA, in addition to enforcement, also regularly engage in advocacy, specifically against rescheduling marijuana, by publishing policy-based papers on certain drugs. Figures such as Ifetayo Harvey, founder and executive of the People of Color Psychedelic Collective, have criticized the DEA for using tax dollars in what they call an attempt to change public opinion, a practice they call an overreach from the scope of the agency's job of enforcement. They claim that the DEA releasing such non-peer-reviewed reports is a transparent attempt to justify its own activities and that since it is not by law an advocacy group but rather a legal enforcement group, those press releases are tantamount to what they consider domestic propaganda.
=== Insufficient monitoring of David Headley ===
The DEA faced a major setback for not keeping stringent observation on Pakistani-American informant David Headley, for involvement in the November 2008 terror attacks in Mumbai, as well as conspiring a terror attack on the Danish newspaper Jyllands-Posten for the cartoons of Muhammad. Headley, while working with the DEA, took part in the plot by providing reconnaissance to the Pakistan based terror outfit Lashkar-e-Taiba, which he was introduced to while visiting Pakistan. On January 24, 2013, a U.S. federal court eventually sentenced Headley to 35 years in prison for his role in Mumbai and Copenhagen.
== Raids on medical marijuana dispensaries ==
The DEA has taken a particularly strong stance on enforcement of the Controlled Substances Act on persons and organizations acting within state laws that allow medical cannabis cultivation and distribution. DEA chief Chuck Rosenberg has made negative comments on patients who use medical marijuana, saying he considers medical marijuana to be a "joke". As a reaction against the negative statements made by Rosenberg towards medical marijuana, an international online petition has been formed. More than 159,737 signatures have been gathered globally with the intention that Rosenberg be fired or forced to resign as head of DEA.
"The people of California and the County of Santa Cruz have overwhelmingly supported the provision of medical marijuana for people who have serious illnesses," county Supervisor Mardi Wormhoudt told the San Francisco Chronicle. "These people (blocking the road) are people with AIDS and cancer and other grave illnesses. To attack these people, who work collectively and have never taken money for their work, is outrageous."
As a result, the Wo/Men's Alliance for Medical Marijuana, with the City and County of Santa Cruz, had sued the DEA, Attorney General Michael Mukasey, and the ONDCP. The most recent court decision rejected the government's motion to dismiss, which allowed discovery to move forward. The American Civil Liberties Union hailed the decision as "a first-of-its-kind ruling."
More recently, the DEA has escalated its enforcement efforts on the recently proliferated Los Angeles area medical cannabis collectives. On July 25, 2007, the DEA raided the California Patients Group, Hollywood Compassionate Collective, and Natural Hybrid (NHI Caregivers) in Hollywood, California. Earlier that day, the operators of those collectives participated in a press conference with LA City Council members announcing the city's intention to regulate the collectives and asking the DEA to halt raids on collectives while the City drafted regulations. The dispensary operator of Natural Hybrid (NHI Caregivers) was forced to close down the collective due to the tremendous loss caused by the DEA conducted joint task force raid against them.
== Project Cassandra ==
In 2008 the Special Operations part of the agency launched a multi-agency effort named Project Cassandra to investigate Hezbollah for allegations of illicit drug trafficking and terrorist financing. The investigation identified an Iranian cell in the U.S. which worked in concert with a Lebanese bank called the Lebanese Canadian Bank to launder money using the purchase of used automobiles exported to Africa. Project Cassandra also identified hemispheric drug syndicates involved in cocaine trafficking in order to finance Hezbollah activities. The Department of Justice issued several sealed indictments but declined to seize, prosecute, extradite, or further investigate likely targets of these alleged foreign criminal activities operating in the United States due to White House diplomatic objectives involving the international nuclear agreement with Iran. On December 22, 2017, Attorney General Jeff Sessions ordered a review of prior cases in the project.
== DEA Museum ==
In 1999, the DEA opened the Drug Enforcement Administration Museum in Arlington County, Virginia. The original permanent exhibit – Illegal Drugs in America: A Modern History – remains the museum's centerpiece. The exhibit features "the more than 150 year history of drugs and drug abuse and the DEA," including a considerable collection of drug paraphernalia and an image of a smiling drug vendor under the heading "Jimmy's Joint".
== In popular culture ==
The DEA are commonly featured in crime drama films and TV, as both protagonists and antagonists.
Hank Schrader is one of the main protagonists in AMC's Breaking Bad. He is both a DEA agent (later promoted to ASAC) and brother-in-law to drug kingpin Walter White, unknowingly investigating Walt's alter-ego Heisenberg for the duration of the show.
Javier Peña and Stephen Murphy are two of the main protagonists in Netflix's Narcos. They are responsible for the capture and killing of the Colombian drug lord Pablo Escobar on December 2, 1993, of which the show was based on.
Norman Stansfield leads a team of corrupt DEA agents, who along with the NYPD, hunt an assassin in the 1994 movie Léon: The Professional.
In the film Sabotage, a group of special agents with the DEA's Special Operations Team, are hunted down after stealing a large amount of cartel cash during a raid.
== See also ==
DEA Purple Heart Award
Departamento Administrativo de Seguridad (former Colombian counterpart)
Diplomatic Security Service (DSS), U.S. State Department
Federal Bureau of Investigation (FBI)
Federal Drug Control Service (Russian former counterpart)
Immigration and Customs Enforcement (ICE)
List of United States federal law enforcement agencies
Main Directorate for Drugs Control (Russian counterpart)
Office of Criminal Investigations
Operation Money Badger
Operation Panama Express
Operation Tiburon (most successful counter-drug operation)
Regulation of therapeutic goods in the United States
Title 21 of the Code of Federal Regulations
U.S. Customs and Border Protection (CBP)
== References ==
== Further reading ==
Harry J. Anslinger and Will Oursler (1961). The Murderers: The Story of the Narcotic Gangs. New York: Farrar, Straus and Cudahy.
Edward Jay Epstein (1977). Agency of Fear: Opiates and Political Power in America. New York: Putnam.
King, Rufus (1972). The Drug Hang-Up: America's Fifty Year Folly
Luno, Nathan Results of America's Drug War; Archived January 14, 2009, at the Wayback Machine. TheDEA.og.
"98 Percent of All Domestically Eradicated Marijuana Is 'Ditchweed,' DEA Admits". NORML. September 7, 2006. Archived from the original on September 27, 2011. Retrieved March 27, 2007.
Major Studies of Drugs and Drug Policy—Schaffer Library of Drug Policy
Smith, Wayne (2012). Waffle House Diaries. Chattanooga, TN: Bluehotel Press.
== External links ==
Official website
Archives of late 1990s websites (usdoj.gov/dea/) at the Wayback Machine (archive index)
DEA Tip Line
Drug Enforcement Administration in the Federal Register
List of former DEA Administrators
Office of Diversion Control
A response to the DEA web site
DEA Watch
DrugEnforcementEdu.org
Get Smart About Drugs – A DEA Resource for Parents
DEA Demand Reduction – Street Smart Prevention
DEA Museum | Wikipedia/US_Drug_Enforcement_Administration |
The environmental impacts caused by the production of illicit drugs is an often neglected topic when analysing the effects of such substances. However, due to the clandestine nature of illicit drug production, its effects can be highly destructive yet difficult to detect and measure. The consequences differ depending upon the drug being produced but can be largely categorised into impacts caused by natural drugs or caused by synthetic/semi-synthetic drugs. Natural drugs refer to drugs which are primarily extracted from a natural source such as cocaine or cannabis. Synthetic drugs are produced from material that can't be found in nature and semi-synthetic drugs are made from both natural and synthetic materials such as methamphetamine and MDMA. Drug policy is a large determinant on how organisations produce drugs and thereby, how their processes affect the environment, thus prompting Government bodies to analyse the current drug policy. It is inevitable that solutions to such environmental impacts are synonymous with solutions to overall illicit drug production, however many have noted the reactionary measures undertaken by government bodies and elevate the need of preventative measures instead.
== Environmental impacts of natural drugs ==
Natural drugs are those whose constituents are primarily extracted from natural sources such as cocaine or marijuana. The environmental impacts associated with such drugs include deforestation, watershed depletion and greenhouse gas emissions.
=== Marijuana ===
With the ease of access to marijuana increasing due to legalisation in parts of North America and Canada many have noted the increasing importance of measuring its possible environmental ramifications. As marijuana has been previously illegal in these areas there is now an opportunity to measure these outcomes. However, there have already been a variety of known consequences caused by the production of marijuana.
Watershed depletion is a serious issue that can be caused by marijuana production. Marijuana cultivation requires large amounts of water, where a single plant can require 8-10 gallons of water per day. This sparks concern, especially in areas susceptible to water shortages such as California. California is the largest producer of marijuana in the U.S yet has had issues surrounding water supply and sanitation for a number of years. In 2012, it was estimated that at least 3,177,241,050 gallons of water were used in the production of marijuana in California. Thus, marijuana production can have severe implications on watershed levels with a number of organisations calling for stricter regulations as marijuana becomes more widespread.
The production of marijuana also requires large amounts of energy due to the controlling of environmental conditions. This further causes high levels of greenhouse gas emissions and energy consumption. "In 2015, the average electricity consumption of a 5,000-square-foot indoor facility in Boulder County was 41,808 kilowatt-hours per month, while an average household in the county used about 630 kilowatt-hours". Such high levels of energy consumption in turn, result in high greenhouse gas emissions. In 2016, it was estimated that on average the production of one kilogram of marijuana produced 4,600 kilograms of carbon dioxide. Thus, marijuana cultivation produces 15 million metric tons of carbon dioxide in the United States in a single year.
=== Cocaine ===
Most of the world's cocaine is produced in South America, particularly in the Andean region. The environmental destruction caused by the production of cocaine has been well documented, with reports made the UN and other government bodies. Due to the illegal nature of coca production, farmers make little effort in soil conservation and sustainability practices as seen in the high mobility and short life of coca plots in Colombia.
One of the major implications of cocaine production is deforestation as large areas of forest are cleared for coca cultivation. The UNODC approximated that 97,622 hectares of primary forest were cleared for coca cultivation during 2001-2004 in the Andean region. This further causes habitat destruction, especially in biodiversity hotspots, areas rich in a variety of species. Such areas are chosen for coca cultivation due to their remote locations, minimising chances of detection. Deforestation has further impacts of soil erosion which further inhibits the survival of native species.
The use of pesticides can also cause severely affect the environment. Farmers are able to sue un-regulated and highly toxic pesticides due to the clandestine nature of drug production. The use of such pesticides can have both direct and indirect effects on the ecosystem. Where lethal levels of exposure directly cause the death of fauna, which is further carried up the food chain where secondary feeders who consume the poisoned animals are also impacted. Furthermore, non-lethal levels of exposure can also cause weaker immune system development and neurological issues, further increasing mortality rates.
== Environmental impacts of synthetic/semi-synthetic drugs ==
Synthetic drugs are those which are primarily derived from inorganic substances. Semi-synthetic are a hybrid of both synthetic and natural drugs, however as both synthetic and semi-synthetic drugs undergo an array of chemical processes during production, their environmental impact are quite similar.
=== Methamphetamine ===
Methamphetamine or meth is a synthetic drug which can be produced on a domestic scale.
The dumping of toxic waste is a major issue associated with the production of meth. It has been approximated that for each pound of meth produced, five pounds of toxic waste are also generated. The methods of disposal of these substances can be extremely damaging to the environment as producers may simply pour them down the sink or toilet. However, such methods allow producers to be more easily detected thus, producers sometimes adopt more environmentally destructive methods such as leaving waste in remote locations such as forests or buried underground where the waste can harm flora and fauna. Producers have also used specialised trucks or vans, equipped with pumps and hose to drain waste onto the road as the vehicle moves. This decreases their chance of detection yet spreads the damage caused by the toxic waste.
The production of meth also produces a number of toxic gases that can harm the human respiratory system and devastate the environment. High levels of phosphine gas can be produced during meth production which can further cause headaches, convulsions and death. The production of meth further produces hydrogen chloride gas, which when released into the environment cause damage metal structures and buildings. Hydrogen chloride is also highly soluble and readily dissolves into water bodies where it can harm the aquatic life. This high solubility also causes it to be quickly washed out by rain in the atmosphere, further causing acid rain where high levels of such rain can have drastic impacts on the environment.
== Environmental impacts of drug policy ==
Drug policy is a determining factor on drug production as it partially dictates the methods through which illicit drugs are produced and transported. Thus, when determining such policies the environmental consequences are sometimes overlooked, resulting in effects which magnify the damage done unto the environment. This is apparent in coca cultivation in the Andean Region, where drug policy has forced producers into more remote locations to avoid detection. In such ungoverned areas, producers maximise their damage through deforestation and toxic pesticide use, destroying these resource rich areas. These effects of drug policy have been noted by a number of government bodies including the UNDP who stated that some eradication campaigns “have not eradicated illicit production but rather displaced it to new areas of greater environmental significance.”
Policies involving drug trafficking have also had adverse effects on the environment. One key aspect of drug trafficking is the need to establish landing areas, usually by clearing land and deforestation. Once established, such areas further accelerate other illegal trafficking activities such as wildlife, marine and timber trafficking as drug traffickers may diversify their operations to expand their networks. Furthermore, as governments policies restrict the movement of traffickers, they must find alternate and more remote routes to transport their materials. These alternate routes typically require further land clearing and habitat destruction, thus further harming the environment.
Drug policy can further inhibit biodiversity conservation. As drug policy can displace the actions of traffickers and producers into more biodiverse locations, their impact on global biodiversity is magnified. As producers relocate into more remote locations, their actions of deforestation and dumping of toxic materials such as kerosene and hydrochloric acid can greatly damage biodiversity. Furthermore, anti-drug initiatives and policies can further drain funding and diminish resources available for environmental protection initiatives. Areas known for illicit-drug production can further discourage tourism, conservation activists and local law enforcement. This allows drug producers to conduct themselves with more freedom and thereby increase their damage. Furthermore, the lack of tourism in such areas limits the revenue of local conservation efforts and the transparency of theses issues.
== Possible solutions ==
Due to the nature of illicit drug production, it is inevitable that solutions to these environmental issues are synonymous with overall drug production prevention. However, by taking environmental impacts into account when formulating drug policies it is possible to better mitigate this damage. Changes in approach have been highlighted as a key method to help target these environmental concerns. This involves analysing and these environmental impacts when assessing the effects of illicit drugs and informing the illicit drug consumer base and law-makers of these impacts.
Improved cooperation between international, national and regional-level organisations allows for a more-informed and sustainable solution to drug production. Previous collaborative efforts have involved more reactory responses which moreso displaced drug operations rather than prevented. A more integrated response between different organisations allows for more preventative measures to be implemented. Furthermore, as much of the environmental impacts occur in transit countries, not just countries of origin, greater integration between different organisations could allow for preventative policies in transit countries to be established. An example of this improved cooperation can be seen in Plan Colombia, which saw the collaboration between the U.S and the Colombian Government to combat drug production. The project saw a decrease in coca cultivation in Colombia from 160,000 hectares to 48,000 hectares and a decrease in the drug-related economy from US$7.5 billion to US$4.5 billion from 2008-2013.
Quelling the demand for illicit drugs has also been considered as a solution to the environmental impacts involved with drug production. That is, by reassessing current anti-drug propaganda and intertwining drug-related health issues with the environmental impacts of illicit drug production a decrease in demand may be achieved. Shifting the approach of current advertisements to focus on such issues may better inform the public and consumers of illicit drugs of these environmental problems. This notion can be further carried into children's drug education, where placing greater emphasis on the environmental effects alongside the traditional and well known health effects may incite a greater reaction. It has also been suggested that besides just revealing these issues it is important for advertising bodies to communicate the contribution individuals make by consuming illicit drugs, thereby increasing their sense of self-value and lessening their dependence on illicit drugs. Enlightening more consumers of such problems may also accrue a larger audience and support for anti-drug solutions. However, even if such a response fails to stem demand, shedding light on these issues may foster voter concerns who still may appeal to legislators.
== Sources ==
== External links == | Wikipedia/Environmental_impact_of_illicit_drug_production |
The illegal drug trade, drug trafficking, or narcotrafficking is a global black market dedicated to the cultivation, manufacture, distribution and sale of prohibited drugs. Most jurisdictions prohibit trade, except under license, of many types of drugs through the use of drug prohibition laws. The think tank Global Financial Integrity's Transnational Crime and the Developing World report estimates the size of the global illicit drug market between US$426 and US$652 billion in 2014, which is equal to the UK's national debt alone. With a world GDP of US$78 trillion in the same year, the illegal drug trade may be estimated as nearly 1% of total global trade. Consumption of illegal drugs is widespread globally, and it remains very difficult for local authorities to reduce the rates of drug consumption.
== History ==
Prior to the 20th century, governments rarely made a major effort to proscribe recreational drug use, though several smoking bans were passed by authorities in Europe and Asia during the early modern era. Tobacco and opium were the two first drugs to be subject to prohibitory government legislation, with officials in New Spain, the Ottoman Empire, Germany, Austria and the Russian Empire passing laws against smoking tobacco; the government of the Qing dynasty issued edicts banning opium smoking in 1730, 1796 and 1800. Beginning in the 18th century, the East India Company (EIC) began to smuggle Indian opium to Chinese merchants, resulting in the creation of an illegal drug trade in China. By 1838, there were between four and 12 million opium addicts in China, and Qing officials responded by strengthening their suppression of the illegal opium trade. Incidents such as the destruction of opium at Humen led to the outbreak of the First Opium War between China and Britain in 1839; the 1842 Treaty of Nanking ending the war did not legalize the importation of opium into China, but Western merchants continued to smuggle the drug to Chinese merchants in ever-increasing amounts. The 1858 Treaty of Tianjin, which ended the Second Opium War, stipulated that the Qing government would open several ports to foreign trade, including opium.
Western governments began prohibiting addictive drugs during the late 19th and early 20th centuries. In 1868, as a result of the increased use of opium in Britain, the British government restricted the sale of opium by implementing the 1868 Pharmacy Act. In the United States, control of opium remained under the control of individual US states until the introduction of the Harrison Act in 1914, after 12 international powers signed the International Opium Convention in 1912. Between 1920 and c. 1933, the Eighteenth Amendment to the United States Constitution banned alcohol in the United States. Prohibition proved almost impossible to enforce and resulted in the rise of organized crime, including the modern American Mafia, which identified enormous business opportunities in the manufacturing, smuggling and sale of illicit liquor.
The beginning of the 21st century saw drug use increase in North America and Europe, with a particularly increased demand for marijuana and cocaine. As a result, international organized crime syndicates such as the Sinaloa Cartel and 'Ndrangheta have increased cooperation among each other in order to facilitate trans-Atlantic drug-trafficking. Use of another illicit drug, hashish, has also increased in Europe. Drug trafficking is widely regarded by lawmakers as a serious offense around the world. Penalties often depend on the type of drug (and its classification in the country into which it is being trafficked), the quantity trafficked, where the drugs are sold and how they are distributed. If the drugs are sold to underage people, then the penalties for trafficking may be harsher than in other circumstances.
Drug smuggling carries severe penalties in many countries. Sentencing may include lengthy periods of incarceration, flogging and even the death penalty (in Singapore, Malaysia, Indonesia and elsewhere). In December 2005, Van Tuong Nguyen, a 25-year-old Australian drug smuggler, was hanged in Singapore after being convicted in March 2004. In 2010, two people were sentenced to death in Malaysia for trafficking 1 kilogram (2.2 lb) of cannabis into the country. Execution is mostly used as a deterrent, and many have called upon much more effective measures to be taken by countries to tackle drug trafficking; for example, targeting specific criminal organisations that are often also active in the smuggling of other goods (i.e. wildlife) and even people. In many cases, links between politicians and the criminal organisations have been proven to exist. In June 2021, Interpol revealed an operation in 92 countries that shut down 113,000 websites and online marketplaces selling counterfeit or illicit medicines and medical products a month earlier, led to the arrests of 227 people worldwide, recovered pharmaceutical products worth $23 million, and led to the seizure of approximately nine million devices and drugs, including large quantities of fake COVID-19 tests and face masks.
== Societal effects ==
The countries of drug production and transit are some of the most affected by the trade, though countries receiving the illegally imported substances are also adversely affected. For example, Ecuador has absorbed up to 300,000 refugees from Colombia who are running from guerrillas, paramilitaries and drug lords. While some applied for asylum, others are still illegal immigrants. The drugs that pass from Colombia through Ecuador to other parts of South America create economic and social problems.
Honduras, through which an estimated 79% of cocaine passes on its way to the United States, had, as of 2011, the highest murder rate in the world. According to the International Crisis Group, the most violent regions in Central America, particularly along the Guatemala–Honduras border, are highly correlated with an abundance of drug trafficking activity.
=== Violent crime ===
In several countries, the illegal drug trade is thought to be directly linked to violent crimes such as murder and gun violence. This is especially true in all developing
countries, such as Honduras, but is also an issue for many developed countries worldwide. In the late 1990s in the United States, the Federal Bureau of Investigation estimated that 5% of murders were drug-related. In Colombia, drug violence can be caused by factors such as the economy, poor governments, and no authority within law enforcement.
After a crackdown by US and Mexican authorities in the first decade of the 21st century as part of tightened border security in the wake of the September 11 attacks, border violence inside Mexico surged. The Mexican government estimated that 90% of the killings were drug-related.
A report by the UK government's Drug Strategy Unit that was leaked to the press, stated that due to the expensive price of highly addictive drugs heroin and cocaine, drug use was responsible for the great majority of crime, including 85% of shoplifting, 70–80% of burglaries and 54% of robberies. It concluded "[t]he cost of crime committed to support illegal cocaine and heroin habits amounts to £16 billion a year in the UK"
== Drug trafficking routes ==
=== Africa ===
==== East and South ====
Heroin is increasingly trafficked from Afghanistan to Europe and America through eastern and southern African countries. This path is known as the "southern route" or "smack track". Repercussions of this trade include burgeoning heroin use and political corruption among intermediary African nations.
==== West ====
Cocaine produced in Colombia and Bolivia has increasingly been shipped via West Africa (especially in Nigeria, Cape Verde, Guinea-Bissau, Cameroon, Mali, Benin, Togo, and Ghana). The money is often laundered in countries such as Nigeria, Ghana, and Senegal.
According to the Africa Economic Institute, the value of illicit drug smuggling in Guinea-Bissau is almost twice the value of the country's GDP. Police officers are often bribed. A police officer's normal monthly wage of $93 is less than 2% of the value of 1 kilogram (2.2 lb) of cocaine (€7000 or $8750). The money can also be laundered using real estate. A house is built using illegal funds, and when the house is sold, legal money is earned. When drugs are sent over land, through the Sahara, the drug traders have been forced to cooperate with terrorist organizations, such as Al-Qaeda in Islamic Maghreb.
=== Asia ===
Drugs in Asia traditionally traveled the southern routes – the main caravan axes of Southeast Asia and Southern China – and include the former opium-producing countries of Thailand, Iran, and Pakistan. After the 1990s, particularly after the end of the Cold War (1991), borders were opened and trading and customs agreements were signed so that the routes expanded to include China, Central Asia, and Russia. There are, therefore, diversified drug trafficking routes available today, particularly in the heroin trade and these thrive due to the continuous development of new markets. A large amount of drugs are smuggled into Europe from Asia. The main sources of these drugs are Afghanistan, along with countries that constituted the so-called Golden Crescent. From these producers, drugs are smuggled into the West and Central Asia to its destinations in Europe and the United States. Iran is now a common route for smugglers, having been previously a primary trading route, due to its large-scale and costly war against drug trafficking. The Border Police Chief of Iran said that his country "is a strong barrier against the trafficking of illegal drugs to Caucasus, especially the Republic of Azerbaijan." The drugs produced by the Golden Triangle of Myanmar, Laos, and Thailand, on the other hand, pass through the southern routes to feed the Australian, US, and Asian markets.
=== South America ===
Venezuela has been a path to the United States and Europe for illegal drugs originating in Colombia, through Central America, Mexico and Caribbean countries such as Haiti, the Dominican Republic, and Puerto Rico.
According to the United Nations, cocaine trafficking through Venezuela increased from 2002 to 2008. In 2005, the government of Hugo Chávez severed ties with the United States Drug Enforcement Administration (DEA), accusing its representatives of spying. Following the departure of the DEA from Venezuela and the expansion of DEA's partnership with Colombia in 2005, Venezuela became more attractive to drug traffickers. Between 2008 and 2012, Venezuela's cocaine seizure ranking among other countries declined, going from being ranked fourth in the world for cocaine seizures in 2008 to sixth in the world in 2012.
On 18 November 2016, following what was known as the Narcosobrinos incident, Venezuelan President Nicolás Maduro's two nephews were found guilty of trying to ship drugs into the United States so they could "obtain a large amount of cash to help their family stay in power".
According to a research conducted by the Israel-based Abba Eban Institute as part of an initiative called Janus Initiative, the main routes that Hezbollah uses for smuggling drugs are from Colombia, Venezuela and Brazil into West Africa and then transported through northern Africa into Europe. This route serves Hezbollah in making a profit in the cocaine smuggling market in order to leverage it for their activities.
== Online trafficking ==
Drugs are increasingly traded online on the dark web on darknet markets. Internet-based drug trafficking is the global distribution of narcotics, making extensive use of technology. Similarly, the use of the Internet for the illegal trafficking of two controlled categories of drugs can also be identified as Internet-related drug trafficking. The platform Silk Road provided goods and services to 100,000 buyers before being shut down in October 2013. This prompted the creation of new platforms such as Silk Road 2.0, which were also shut down.
== Profits ==
Statistics about profits from the drug trade are largely unknown due to its illicit nature. An online report published by the UK Home Office in 2007 estimated the illicit drug market in the UK at £4–6.6 billion a year.
In December 2009, United Nations Office on Drugs and Crime Executive Director Antonio Maria Costa claimed illegal drug money saved the banking industry from collapse. He claimed he had seen evidence that the proceeds of organized crime were "the only liquid investment capital" available to some banks on the brink of collapse during 2008. He said that a majority of the $352 billion (£216bn) of drug profits was absorbed into the economic system as a result: "In many instances, the money from drugs was the only liquid investment capital. In the second half of 2008, liquidity was the banking system's main problem and hence liquid capital became an important factor ... Inter-bank loans were funded by money that originated from the drugs trade and other illegal activities...there were signs that some banks were rescued that way".
Costa declined to identify countries or banks that may have received any drug money, saying that would be inappropriate because his office is supposed to address the problem, not apportion blame.
Though street-level drug sales are widely viewed as lucrative, a study by Sudhir Venkatesh suggested that many low-level employees receive low wages. In a study he made in the 1990s working closely with members of the Black Gangster Disciple Nation in Chicago, he found that one gang (essentially a franchise) consisted of a leader (a college graduate named J.T.), three senior officers, and 25 to 75 street level salesmen ('foot soldiers') depending on season. Selling crack cocaine, they took in approximately $32,000 per month over a six-year period. This was spent as follows: $5,000 to the board of twenty directors of the Black Gangster Disciple Nation, who oversaw 100 such gangs for approximately $500,000 in monthly income. Another $5,000 monthly was paid for cocaine, and $4,000 for other non-wage expenses. J.T. took $8,500 monthly for his own salary. The remaining $9,500 monthly went to pay the employees a $7 per hour wage for officers and a $3.30 per hour wage for foot soldiers. Contrary to a popular image of drug sales as a lucrative profession, many of the employees were living with their mothers by necessity. Despite this, the gang had four times as many unpaid members who dreamed of becoming foot soldiers.
== Impact of free trade ==
There are several arguments on whether or not free trade has a correlation to an increased activity in the illicit drug trade. Currently, the structure and operation of the illicit drug industry is described mainly in terms of an international division of labor. Free trade can open new markets to domestic producers who would otherwise resort to exporting illicit drugs. Additionally, extensive free trade among states increases cross-border drug enforcement and coordination between law enforcement agencies in different countries. However, free trade also increases the sheer volume of legal cross-border trade and provides cover for drug smuggling—by providing ample opportunity to conceal illicit cargo in legal trade. While international free trade continues to expand the volume of legal trade, the ability to detect and interdict drug trafficking is severely diminished. Towards the late 1990s, the top ten seaports in the world processed 33.6 million containers. Free trade has fostered integration of financial markets and has provided drug traffickers with more opportunities to launder money and invest in other activities. This strengthens the drug industry while weakening the efforts of law enforcement to monitor the flow of drug money into the legitimate economy. Cooperation among cartels expands their scope to distant markets and strengthens their abilities to evade detection by local law enforcement. Additionally, criminal organizations work together to coordinate money-laundering activities by having separate organizations handle specific stages of laundering process. One organization structures the process of how financial transactions will be laundered, while another criminal group provides the "dirty" money to be cleaned. By fostering expansion of trade and global transportation networks, free trade encourages cooperation and formation of alliances among criminal organizations across different countries.
The drug trade in Latin America emerged in the early 1930s. It saw significant growth in the Andean countries, including Peru, Bolivia, Chile, Ecuador, Colombia and Venezuela. The underground market in the early half of the 20th century mainly had ties to Europe. After World War II, the Andean countries saw an expansion of trade, specifically with cocaine.
== Drug trafficking by country ==
=== Syria ===
The Ba'athist government of Syria ruled by the Al-Assad family is known for its extensive involvement in drug trade since the 1970s. As of 2022, the Syrian government financed the biggest multi-billion dollar drug trade in the world, mostly focused on an illegal drug known as Captagon, making it the world's largest narco-state. Its revenues from Captagon smuggling alone is estimated to worth 57 billion dollars annually in 2022, which is approximately thrice the total trade of all Mexican cartels. General Maher al-Assad, younger brother of Syrian dictator Bashar al-Assad and commander of the Fourth Armoured Division, directly supervised the production, smuggling and profiteering of the drug business. Already suffering from severe financial problems as a result of corruption and civil war, profits from Captagon are said to be the "lifeline" of the Assad regime, through which it earned more than 90% of its total revenue. The smugglers receive direct training from Syrian military to successfully conduct trafficking operations.
Republican Guard, commanded by Maher al-Assad was one of the main Ba'athist military divisions that was engaged in perpetrating brutal crackdowns and mass violence against protestors across the country. In 2018, Bashar al-Assad assigned Maher as the commander of the 4th Armoured Division, a military unit that supervised the Assad regime's criminal enterprises like smuggling, drug trafficking, narcotics production and plunder of goods and resources. Under Maher's supervision, the 4th Armoured Division expanded captagon production and trafficking from Syria into a "business model controlled by the regime".
In 2022, 90% of all captagon pills manufactured in Syria exported by drug cartels affiliated with Assad regime arrived at its customer destinations across the world. Although hundreds of millions of pills were intercepted and seized by police forces, these accounted only for 10% of the total captagon exports of the drug cartels linked to the Assad regime. In 2020, Italian police seized 84 million captagon pills originating from Syrian ports while intercepting a single shipment. In June 2023, US State Department's Bureau of Near Eastern Affairs published a detailed report to the US Congress, elucidating a strategy to eliminate the narcotics production, drug trafficking and drug cartel networks affiliated with the Assad regime and Hezbollah.
A joint investigation conducted by Organized Crime and Corruption Reporting Project (OCCRP) and BBC News Arabic published a documentary in June 2023, revealing further details about the activities of regime officials, Ba'athist military commanders and Assad family members in their involvement in Syria's drug cartel. The investigation found that Lebanese criminal and drug kingpin Hassan Daqou collaborated with Syria's Fourth Armoured Division on trafficiking billions of dollars of drugs, under the command of General Ghassan Bilal, the right-hand man of Maher al-Assad. The report also unearthed Hezbollah's close participation in the drug production and smuggling networks. The Fourth Armoured Division, being an elite military unit permitted to move freely across Assad regime's checkpoints, oversees the smuggling operations from Syria, including the trafficking of cash, weapons, illegal drugs, etc. Days after the publication of the joint BBC-OCCRP documentary; Assad government banned all activities of BBC media outlets and entry of affiliated media personnel in Syria.
The extensive involvement of Syrian Armed Forces in sponsorship of drug production and trade has led to pervasive drug addiction problems amongst pro-Assad soldiers. In many instances, military officials encourage the soldiers to consume Captagon and other illegal drugs, leading to overdose or drug abuse. Pro-Assad fighters in the National Defence Forces and Hezbollah also consume illegal drugs in large quantities. In July 2023, German police busted a major captagon network run by two Syrian-born men in southern German state of Bavaria. Assad regime sponsors the largest Captagon production network in Syria; which is the source of about 80% of total captagon supply in the world.
In an investigative report published by The Insider news-outlet in 2024, journalist Yuriy Matsarsky stated:"...Captagon produced in underground labs—and in actual Syrian pharmaceutical facilities—is distributed to the fighters of Bashar Assad's army. Interestingly, however, the quantities the country produces far exceed its own military’s demand. ... By some estimates, this business gives Syria more money than its entire legal export, and the regime constantly works to increase its profits, primarily by expanding its market reach. To this end, criminal gangs associated with Damascus or Hezbollah have built distribution networks for Captagon in countries where the drug was not previously popular."
=== United States ===
==== Background ====
The effects of the illegal drug trade in the United States can be seen in a range of political, economic and social aspects. Increasing drug related violence can be tied to the racial tension that arose during the late 20th century along with the political upheaval prevalent throughout the 1960s and 70s. The second half of the 20th century was a period when increased wealth, and increased discretionary spending, increased the demand for illicit drugs in certain areas of the United States. Large-scale drug trafficking is one of the capital crimes, and may result in a death sentence prescribed at the federal level when it involves murder.
==== Political impact ====
A large generation, the baby boomers, came of age in the 1960s. Their social tendency to confront the law on specific issues, including illegal drugs, overwhelmed the understaffed judicial system. The federal government attempted to enforce the law, but with meager effect.
Marijuana was a popular drug seen through the Latin American trade route in the 1960s. Cocaine became a major drug product in the later decades. Much of the cocaine is smuggled from Colombia and Mexico via Jamaica. This led to several administrations combating the popularity of these drugs. Due to the influence of this development on the US economy, the Reagan administration began "certifying" countries for their attempts at controlling drug trafficking. This allowed the United States to intervene in activities related to illegal drug transport in Latin America. Continuing into the 1980s, the United States instated stricter policy pertaining to drug transit through sea. As a result, there was an influx in drug-trafficking across the Mexico–US border, which increased the drug cartel activity in Mexico.
By the early 1990s, so much as 50% of the cocaine available in the United States market originated from Mexico, and by the 2000s, over 90% of the cocaine in the United States was imported from Mexico. In Colombia, however, there was a fall of the major drug cartels in the mid-1990s. Visible shifts occurred in the drug market in the United States. Between 1996 and 2000, US cocaine consumption dropped by 11%.
In 2008, the US government initiated another program, known as the Merida Initiative, to help combat drug trafficking in Mexico. This program increased US security assistance to $1.4 billion over several years, which helped supply Mexican forces with "high-end equipment from helicopters to surveillance technology". Despite US aid, Mexican "narcogangs" continue to outnumber and outgun the Mexican Army, allowing for continued activities of drug cartels across the US–Mexico border.
==== Social impacts ====
Although narcotics are illegal in the US, they have become integrated into the nation's culture and are seen as a recreational activity by sections of the population. Illicit drugs are considered to be a commodity with strong demand, as they are typically sold at a high value. This high price is caused by a combination of factors that include the potential legal ramifications that exist for suppliers of illicit drugs and their high demand. Despite the constant effort by politicians to win the war on drugs, the US is still the world's largest importer of illegal drugs.
Throughout the 20th century, narcotics other than cocaine also crossed the Mexican border, meeting the US demand for alcohol during the 1920s Prohibition, opiates in the 1940s, marijuana in the 1960s, and heroin in the 1970s. Most of the US imports of drugs come from Mexican drug cartels. In the United States, around 195 cities have been infiltrated by drug trafficking that originated in Mexico. An estimated $10bn of the Mexican drug cartel's profits come from the United States, not only supplying the Mexican drug cartels with the profit necessary for survival, but also furthering America's economic dependence on drugs.
===== Demographics =====
With a large wave of immigrants in the 1960s and onwards, the United States saw an increased heterogeneity in its public. In the 1980s and 1990s, drug-related homicide was at a record high. This increase in drug violence became increasingly tied to these ethnic minorities. Though the rate of violence varied tremendously among cities in America, it was a common anxiety in communities across urban America. An example of this could be seen in Miami, a city with a host of ethnic enclaves. Between 1985 and 1995, the homicide rate in Miami was one of the highest in the nation—four times the national homicide average. This crime rate was correlated with regions with low employment and was not entirely dependent on ethnicity.
The baby boomer generation also felt the effects of the drug trade in their increased drug use from the 1960s to 1980s. Along with substance use, criminal involvement, suicide and murder were also on the rise. Due to the large amount of baby boomers, commercial marijuana use was on the rise. This increased the supply and demand for marijuana during this time period.
=== Mexico ===
==== Political influences ====
Corruption in Mexico has contributed to the domination of Mexican cartels in the illicit drug trade. Since the beginning of the 20th century, Mexico's political environment allowed the growth of drug-related activity. The loose regulation over the transportation of illegal drugs and the failure to prosecute known drug traffickers and gangs increased the growth of the drug industry. Toleration of drug trafficking has undermined the authority of the Mexican government and has decreased the power of law enforcement officers in regulation over such activities. These policies of tolerance fostered the growing power of drug cartels in the Mexican economy and have made drug traders wealthier. Many states in Mexico lack policies that establish stability in governance. There also is a lack of local stability, as mayors cannot be re-elected. This requires electing a new mayor each term. Drug gangs have manipulated this, using vacuums in local leadership to their own advantage.
In 1929, the Institutional Revolutionary Party (PRI) was formed to resolve the chaos resulting from the Mexican Revolution. Over time, this party gained political influence and had a major impact on Mexico's social and economic policies. The party created ties with various groups as a power play in order to gain influence, and as a result created more corruption in the government. One such power play was an alliance with drug traffickers. This political corruption obscured justice, making it difficult to identify violence when it related to drugs. By the 1940s, the tie between the drug cartels and the PRI had solidified. This arrangement created immunity for the leaders of the drug cartels and allowed drug trafficking to grow under the protection of the government officials.
During the 1990s, the PRI lost some elections to the new National Action Party (PAN). Chaos again emerged as elected government in Mexico changed drastically. As the PAN party took control, drug cartel leaders took advantage of the ensuing confusion and used their existing influence to further gain power. Instead of negotiating with the central government as was done with the PRI party, drug cartels utilized new ways to distribute their supply and continued operating through force and intimidation. As Mexico became more democratized, the corruption fell from a centralized power to the local authorities. Cartels began to bribe local authorities, thus eliminating the structure and rules placed by the government—giving cartels more freedom. As a response, Mexico saw an increase in violence caused by drug trafficking.
The corruption cartels created resulted in distrust of government by the Mexican public. This distrust became more prominent after the collapse of the PRI party. In response, the presidents of Mexico, in the late twentieth century and early twenty-first century, implemented several different programs relating to law enforcement and regulation. In 1993, President Salinas created the National Institute for the Combat of Drugs in Mexico. From 1995 to 1998, President Zedillo established policies regarding increased punishment of organized crime, allowing "[wire taps], protected witnesses, covert agents and seizures of goods", and increasing the quality of law enforcement at the federal level. From 2001 to 2005, President Vicente Fox created the Federal Agency of Investigation.
These policies resulted in the arrests of major drug-trafficking bosses:
==== Mexico's economy ====
Over the past few decades, drug cartels have become integrated into Mexico's economy. Approximately 500 cities are directly engaged in drug trafficking and nearly 450,000 people are employed by drug cartels. Additionally, the livelihood of 3.2 million people is dependent on the drug cartels. Between local and international sales, such as to Europe and the United States, drug cartels in Mexico see a $25–30 bn yearly profit, a great deal of which circulates through international banks such as HSBC. Drug cartels are fundamental in local economics. A percentage of the profits seen from the trade are invested in the local community. Such profits contribute to the education and healthcare of the community. While these cartels bring violence and hazards into communities, they create jobs and provide income for its many members.
==== Culture of drug cartels ====
Major cartels saw growth due to a prominent set culture of Mexican society that created the means for drug capital. One of the sites of origin for drug trafficking within Mexico, was the state of Michoacán. In the past, Michoacán was mainly an agricultural society. This provided an initial growth of trade. Industrialization of rural areas of Mexico facilitated a greater distribution of drugs, expanding the drug market into different provinces. Once towns became industrialized, cartels such as the Sinaloa Cartel started to form and expand. The proliferation of drug cartel culture largely stemmed from the ranchero culture seen in Michoacán. Ranchero culture values the individual as opposed to the society as a whole. This culture fostered the drug culture of valuing the family that is formed within the cartel. This ideal allowed for greater organization within the cartels.
Gangs play a major role in the activity of drug cartels. MS-13 and the 18th Street gang are notorious for their contributions and influence over drug trafficking throughout Latin America. MS-13 has controlled much of the activity in the drug trade spanning from Mexico to Panama. Female involvement is present in the Mexican drug culture. Although females are not treated as equals to males, they typically hold more power than their culture allows and acquire some independence. The increase in power has attracted females from higher social classes. Financial gain has also prompted women to become involved in the illegal drug market. Many women in the lower levels of major drug cartels belong to a low economic class. Drug trafficking offers women an accessible way to earn income. Females from all social classes have become involved in the trade due to outside pressure from their social and economic environments.
=== Colombia ===
==== Political ties ====
It was common for smugglers in Colombia to import liquor, alcohol, cigarettes and textiles, while exporting cocaine. Personnel with knowledge of the terrain were able to supply the local market while also exporting a large amount of product. The established trade initially involved Peru, Bolivia, Colombia, Venezuela and Cuba. Peasant farmers produced coca paste in Peru and Bolivia, while Colombian smugglers would process the coca paste into cocaine in Colombia, and trafficked product through Batista's Cuba. This trade route established ties between Cuban and Colombian organized crime.
From Cuba, cocaine would be transported to Miami, Florida; and Union City, New Jersey. Quantities of the drug were then smuggled throughout the US. The international drug trade created political ties between the involved countries, encouraging the governments of the countries involved to collaborate and instate common policies to eradicate drug cartels. Cuba stopped being a center for transport of cocaine following the Cuban Revolution and the establishment of Fidel Castro's communist government in 1959.
As a result, Miami and Union City became the sole locations for trafficking. The relations between Cuban and Colombian organized crime remained strong until the 1970s, when Colombian cartels began to vie for power. In the 1980s and 90s, Colombia emerged as a key contributor of the drug trade industry in the Western Hemisphere. While the smuggling of drugs such as marijuana, poppy, opium and heroin became more ubiquitous during this time period, the activity of cocaine cartels drove the development of the Latin American drug trade. The trade emerged as a multinational effort as supplies (i.e. coca plant substances) were imported from countries such as Bolivia and Peru, were refined in Colombian cocaine labs and smuggled through Colombia, and exported to countries such as the US.
==== Colombia's economy ====
Colombia has had a significant role in the illegal drug trade in Latin America. While active in the drug trade since the 1930s, Colombia's role in the drug trade did not truly become dominant until the 1970s. When Mexico eradicated marijuana plantations, demand stayed the same. Colombia met much of the demand by growing more marijuana. Grown in the strategic northeast region of Colombia, marijuana soon became the leading cash crop in Colombia. This success was short-lived due to anti-marijuana campaigns that were enforced by the US military throughout the Caribbean. Instead, drug traffickers in Colombia continued their focus on exporting cocaine.
Having been an export of Colombia since the early 1950s, cocaine remained popular for a host of reasons. Colombia's location facilitated its transportation from South America into Central America, and then to its destination of North America. This continued into the 1990s, when Colombia remained the chief exporter of cocaine. The business of drug trafficking can be seen in several stages in Colombia towards the latter half of the 20th century. Colombia served as the dominant force in the distribution and sale of cocaine by the 1980s. As drug producers gained more power, they became more centralized and organized into what became drug cartels.
Cartels controlled the major aspects of each stage in the traffic of their product. Their organization allowed cocaine to be distributed in great amounts throughout the United States. By the late 1980s, intra-industry strife arose within the cartels. This stage was marked by increased violence as different cartels fought for control of export markets. Despite this strife, this power struggle led to then having multiple producers of coca leaf farms. This in turn caused an improvement in quality control and reduction of police interdiction in the distribution of cocaine. This also led to cartels attempting to repatriate their earnings which would eventually make up 5.5% of Colombia's GDP. This drive to repatriate earnings led to the pressure of legitimizing their wealth, causing an increase in violence throughout Colombia.
Throughout the 1980s, estimates of illegal drug value in Colombia ranged from $2bn to $4bn. This made up about 7–10% of the $36bn estimated Gross National Product (GNP) of Colombia during this decade. In the 1990s, the estimates of the illegal drug value remained roughly within the same range (~$2.5bn). As the Colombian GNP rose throughout the 1990s ($68.5bn in 1994 and $96.3bn in 1997), illegal drug values began to comprise a decreasing fraction of the national economy.
By the early 1990s, although Colombia led in the exportation of cocaine, it found increasing confrontations within its state. These confrontations were primarily between cartels and government institutions. This led to a decrease in the drug trade's contribution to the GDP of Colombia; dropping from 5.5% to 2.6%. Though a contributor of wealth, the distribution of cocaine has had negative effects on the socio-political situation of Colombia and has weakened its economy as well.
==== Social impacts ====
By the 1980s, Colombian cartels became the dominant cocaine distributors in the US. This led to the spread of increased violence throughout both Latin America and Miami. In the 1980s, two major drug cartels emerged in Colombia: the Medellín and Cali groups.
Throughout the 1990s however, several factors led to the decline of these major cartels and to the rise of smaller Colombian cartels. The US demand for cocaine dropped while Colombian production rose, pressuring traffickers to find new drugs and markets. In this time period, there was an increase in activity of Caribbean cartels that led to the rise of an alternate route of smuggling through Mexico. This led to the increased collaboration between major Colombian and Mexican drug traffickers. Such drastic changes in the execution of drug trade in Colombia paired with the political instabilities and rise of drug wars in Medellin and Cali, gave way for the rise of the smaller Colombian drug trafficking organizations (and the rise of heroin trade). As the drug trade's influence over the economy increased, drug lords and their networks grew in their power and influence in society. The occurrences in drug-related violence increased during this time period as drug lords fought to maintain their control in the economy.
Typically, a drug cartel had support networks that consisted of a number of individuals. These people individuals ranged from those directly involved in the trade (such as suppliers, chemists, transporters, smugglers, etc.) as well as those involved indirectly in the trade (such as politicians, bankers, police, etc.). As these smaller Colombian drug cartels grew in prevalence, several notable aspects of the Colombian society gave way for further development of the Colombian drug industry. For example, until the late 1980s, the long-term effects of the drug industry were not realized by much of society. Additionally, there was a lack of regulation in prisons where captured traffickers were sent. These prisons were under-regulated, under-funded, and under-staffed, which allowed for the formation of prison gangs, for the smuggling of arms/weapons/etc., for feasible escapes, and even for captured drug lords to continue running their businesses from prison.
=== Western Balkans ===
Since the beginning of the 21st century, the global drug trade network witnessed the emergence of criminal groups from the Western Balkans as crucial players. These groups have moved up from being small-time crooks to major drug distributors. Most of these organized crime groups belonged to Albania, Bosnia and Herzegovina, Kosovo, Montenegro, North Macedonia and Serbia. The illicit trade activities of the Balkans primarily involved Latin America, Western Europe, South Africa, Australia and Turkey. These groups keep their operations outside the Western Balkans, while staying connected to their homeland. Within the network of these groups, the dealmakers operate in a proximity of supply sources and the distribution networks are managed by foot soldiers. However, the bosses of the organized criminal groups stay and keep their wealth in the United Arab Emirates (UAE). The UAE is amongst the enablers of global corruption and illicit financial flows. Analysts have claimed that criminal actors across the world either operate from or through the Emirates. It was a haven for criminals, where the risk for illicit activities remains low.
For the Balkan criminals, a growing trend was to relocate to the UAE, which became an attraction to dirty money and kingpins from several European nations and the United Kingdom. Besides, Dubai was also dubbed as the "new Costa del Crime", replacing the crime hideaway of Spain, the Costa del Sol. The UAE had poor regulations for money laundering and for screening of suspicious transactions. The lack of regulations against illicit financial activities prompted the Financial Action Task Force (FATF) to place the Gulf country on its grey list in March 2022. Consequently, the Emirates' remained a safe option for the criminals. Nearly two-thirds of the Albanian criminal groups, who were active in trade of drugs like cocaine, were believed to be hiding in the UAE. One of such individuals, Eldi Dizdari was accused of international drug trafficking and was living in Dubai. Research revealed that these criminals invested huge amounts in the Emirates' real estate and other economical sectors to live there. Another trafficker of cocaine from Bosnia, Edin Gačanin was living in the UAE using his extensive profits to buy property and protection in the country. Dubbed as the "European Escobar", he connected the supply network between production markets of Latin America and consumer markets of Western European. He was able to evade the arrest and investigations, including by the US Drug Enforcement Administration, by seeking shelter in the Emirates.
== Trade in specific drugs ==
=== Cannabis ===
While the recreational use of (and consequently the distribution of) cannabis is illegal in most countries throughout the world, recreational distribution is legal in some countries, such as Canada, and medical distribution is permitted in some places, such as 38 of the 50 US states (although importation and distribution is still federally prohibited). Beginning in 2014, Uruguay became the first country to legalize cultivation, sale, and consumption of cannabis for recreational use for adult residents. In 2018, Canada became the second country to legalize use, sale and cultivation of cannabis. The first few weeks were met with extremely high demand, most shops being out of stock after operating for only four days.
Cannabis use is tolerated in some areas, most notably the Netherlands, which has legalized the possession and licensed sale (but not cultivation) of the drug. Many nations have decriminalized the possession of small amounts of marijuana. Due to the hardy nature of the cannabis plant, marijuana is grown all across the world; today, it is the world's most popular illegal drug with the highest level of availability. Cannabis is grown legally in many countries for industrial, non-drug use (known as hemp) as well. Cannabis-hemp may also be planted for other non-drug domestic purposes, such as seasoning that occurs in Aceh.
The demand for cannabis around the world, coupled with the drug's relative ease of cultivation, makes the illicit cannabis trade one of the primary ways in which organized criminal groups finance many of their activities. In Mexico, for example, the illicit trafficking of cannabis is thought to constitute the majority of many of the cartels' earnings, and the main way in which the cartels finance many other illegal activities; including the purchase of other illegal drugs for trafficking, and for acquiring weapons that are ultimately used to commit murders (causing a burgeoning in the homicide rates of many areas of the world, but particularly Latin America).
Some studies show that the increased legalization of cannabis in the United States (beginning in 2012 with Washington Initiative 502 and Colorado Amendment 64) has led Mexican cartels to smuggle less cannabis in exchange for more heroin.
=== Alcohol ===
Alcohol, in the context of alcoholic beverages rather than denatured alcohol, is illegal in a number of Muslim countries, such as Saudi Arabia; this has resulted in a thriving illegal trade in alcohol. The manufacture, sale, transportation, import, and export of alcoholic beverages were illegal in the United States during the time known as the Prohibition in the 1920s and early 1930s.
=== Heroin ===
In the 1950s and 1960s, most heroin was produced in Turkey and transshipped in France via the French Connection crime ring, with much of it arriving in the United States. This resulted in the record setting April 26, 1968 seizure of 246 lb (111.6 kg) of heroin smuggled in a vehicle on the SS France (1960) ocean liner. By the time of The French Connection (1971 film), this route was being supplanted.
Then, until c. 2004, the majority of the world's heroin was produced in an area known as the Golden Triangle. However, by 2007, 93% of the opiates on the world market originated in Afghanistan. This amounted to an export value of about US$4 billion, with a quarter being earned by opium farmers and the rest going to district officials, insurgents, warlords and drug traffickers. Another significant area where poppy fields are grown for the manufacture of heroin is Mexico. In November 2023, a U.N report showed that in the entirety of Afghanistan, poppy cultivation dropped by over 95%, removing it from its place as being the world's largest opium producer.
According to the United States Drug Enforcement Administration, the price of heroin is typically valued 8 to 10 times that of cocaine on American streets, making it a high-profit substance for smugglers and dealers. In Europe (except the transit countries Portugal and the Netherlands), for example, a purported gram of street heroin, usually consisting of 700–800 mg of a light to dark brown powder containing 5–10% heroin base, costs €30–70, making the effective value per gram of pure heroin €300–700. Heroin is generally a preferred product for smuggling and distribution—over unrefined opium due to the cost-effectiveness and increased efficacy of heroin.
Because of the high cost per volume, heroin is easily smuggled. A US quarter-sized (2.5 cm) cylindrical vial can contain hundreds of doses. From the 1930s to the early 1970s, the so-called French Connection supplied the majority of US demand. Allegedly, during the Vietnam War, drug lords such as Ike Atkinson used to smuggle hundreds of kilograms of heroin to the US in coffins of dead American soldiers (see Cadaver Connection). Since that time it has become more difficult for drugs to be imported into the US than it had been in previous decades, but that does not stop the heroin smugglers from getting their product across US borders. Purity levels vary greatly by region with Northeastern cities having the most pure heroin in the United States. On 17 October 2018 police in Genoa, Italy discovered 270 kg (600 lb) of heroin hidden in a ship coming from the Iranian southern port of Bandar Abbas. The ship had already passed and stopped at Hamburg in Germany and Valencia in Spain.
Penalties for smuggling heroin or morphine are often harsh in most countries. Some countries will readily hand down a death sentence (e.g. Singapore) or life in prison for the illegal smuggling of heroin or morphine, which are both internationally Schedule I drugs under the Single Convention on Narcotic Drugs.
In May 2021, Romania seized 1.4 tonnes of heroin at Constanța port of a shipment from Iran that was headed for Western Europe.
=== Methamphetamine ===
Methamphetamine is another popular drug among distributors. Three common street names are "meth", "crank", and "ice".
According to the Community Epidemiology Work Group, the number of clandestine methamphetamine laboratory incidents reported to the National Clandestine Laboratory Database decreased from 1999 to 2009. During this period, methamphetamine lab incidents increased in mid-western States (Illinois, Michigan, Missouri, and Ohio), and in Pennsylvania. In 2004, more lab incidents were reported in Missouri (2,788) and Illinois (1,058) than in California (764). In 2003, methamphetamine lab incidents reached new highs in Georgia (250), Minnesota (309), and Texas (677). There were only seven methamphetamine lab incidents reported in Hawaii in 2004, though nearly 59 percent of substance use treatment admissions (excluding alcohol) were for primary methamphetamine use during the first six months of 2004. As of 2007, Missouri leads the United States in drug-lab seizures, with 1,268 incidents reported. Often canine units are used for detecting rolling meth labs which can be concealed on large vehicles, or transported on something as small as a motorcycle. These labs are more difficult to detect than stationary ones, and can often be obscured among legal cargo in big trucks.
Methamphetamine is sometimes used intravenously, placing users and their partners at risk for transmission of HIV and hepatitis C. "Meth" can also be inhaled, most commonly vaporized on aluminum foil or in a glass pipe. This method is reported to give "an unnatural high" and a "brief intense rush".
In South Africa, methamphetamine is called "tik" or "tik-tik". Known locally as "tik", the substance was virtually unknown as late as 2003. Now, it is the country's main addictive substance, even when alcohol is included. Children as young as eight are abusing the substance, smoking it in crude glass vials made from light bulbs. Since methamphetamine is easy to produce, the substance is manufactured locally in staggering quantities.
The government of North Korea currently operates methamphetamine production facilities. There, the drug is used as medicine because no alternatives are available; it also is smuggled across the Chinese border.
The Australian Crime Commission's illicit drug data report for 2011–2012 stated that the average strength of crystal methamphetamine doubled in most Australian jurisdictions within a 12-month period, and the majority of domestic laboratory closures involved small "addict-based" operations.
=== Temazepam ===
Temazepam, a strong hypnotic benzodiazepine, is illicitly manufactured in clandestine laboratories (called jellie labs) to supply the increasingly high demand for the drug internationally. Many clandestine temazepam labs are in Eastern Europe. The labs manufacture temazepam by chemically altering diazepam, oxazepam or lorazepam. "Jellie labs" have been identified and shut down in Russia, Ukraine, Latvia and Belarus.
=== Cocaine ===
Cocaine is a highly trafficked drug. In 2017 the value of the global market for illicit cocaine was estimated at between $94 and $143 billion. In 2022, illicit sales in Europe were estimated at $11.1 billion. In 2020, almost 2,000 tons of cocaine were produced for distribution through illicit markets.
=== Fentanyl ===
Fentanyl, a synthetic opioid, is 20 to 40 times more potent than heroin and 100 times more potent than morphine; its primary clinical utility is in pain management for cancer patients and those recovering from painful surgeries. Illicit use of fentanyl continues to fuel an epidemic of synthetic opioid drug overdose deaths in the US. From 2011 to 2021, synthetic opioid deaths per year increased from 2,600 overdoses to 70,601. Since 2018, fentanyl and its analogues have been responsible for most drug overdose deaths in the US, causing over 71,238 deaths in 2021. Fentanyl is often mixed, cut, or ingested alongside other drugs, including cocaine and heroin. The fentanyl epidemic has erupted in a highly acrimonious dispute between the US and Mexican governments. While US officials blame the flood of fentanyl crossing the border primarily on Mexican crime groups, President Andrés Manuel López Obrador insists that the main source of this synthetic drug is Asia. He believes that the crisis of a lack of family values in the US drives people to use the drug.
== See also ==
Allegations of CIA drug trafficking
Arguments for and against drug prohibition
Corruption
Counterfeit medications
Counterfeit money
Environmental impact of illicit drug production
Rum running
Illicit cigarette trade
Human trafficking
Arms trafficking
Wildlife trafficking
Illegal organ trade
Drug liberalization
Drug trafficking organizations
Golden Crescent
Golden Triangle (Southeast Asia)
Illegal drug trade in the Indian Ocean region
Maritime drug smuggling into Australia
Narco-capitalism
Narco-state
Narcoterrorism
Organized crime
Operation Show Me How
=== International coordination ===
International Day Against Drug Abuse and Illicit Trafficking
Interpol
United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances
== References ==
== External links ==
Official website of the United Nations Office on Drugs and Crime (UNODC)
Illicit drug issues by country, by the CIA. Archived 2010-12-29 at the Wayback Machine. | Wikipedia/Drug_dealer |
The Central Intelligence Agency (CIA) has been accused of involvement in the illegal drug trade. Several works on the subject have received significant attention, including those written by historian Alfred W. McCoy, professor and diplomat Peter Dale Scott, journalists Gary Webb and Alexander Cockburn, and writer Larry Collins. These claims have led to investigations by the federal government of the United States, including hearings and reports by the House of Representatives, Senate, Department of Justice, and the CIA's Inspector General. Their investigations have generally noted that there is no clear evidence CIA itself had ever directly engaged in drug trafficking, although there may have been instances of the organization being indirectly complicit in the activities of others.
== Background ==
According to Tim Weiner, the Central Intelligence Agency "has been accused of forming alliances of convenience with drug traffickers around the world in the name of anti-Communism" since its creation in 1947.
In the early 1970s, Alfred McCoy "accused American officials of condoning and even cooperating with corrupt elements in Southeast Asia's illegal drug trade out of political and military considerations" and stated that the CIA was knowingly involved in the production of heroin in the Golden Triangle of Burma, Thailand, and Laos. The United States Department of State responded to the initial allegations stating that they were "unable to find any evidence to substantiate them, much less proof." Subsequent investigations by the Inspector General of the CIA, United States House Committee on Foreign Affairs, and United States Senate Select Committee to Study Governmental Operations with Respect to Intelligence Activities (i.e. the Church Committee) also found the charges to be unsubstantiated.
In the 1980s, American journalists Anthony Avirgan and Martha Honey claimed that the perpetrator of the La Penca bombing was linked to a drug-financed "Secret Team" of FDN Contras and CIA agents. The Christic Institute then filed a $24 million civil suit on behalf of Avirgan and Honey 30 charging defendants—including CIA officials—of illegally participating in assassinations, as well as arms and drug trafficking. A judge for the United States District Court for the Southern District of Florida found that the plaintiffs "made no showing of existence of genuine issues of material fact" and ordered the Christic Institute to pay over $1 million in attorneys fees and court costs. The United States Court of Appeals for the Eleventh Circuit affirmed the ruling, and the Supreme Court of the United States let the judgment stand by refusing to hear an additional appeal.
In August 1996, Gary Webb's three-part series of articles titled Dark Alliance was published by the San Jose Mercury News. Webb's series raised allegations that U.S. government officials—including Central Intelligence Agency (CIA) and Department of Justice (DOJ) employees—either ignored or protected drug dealers in Southern California who were associated with the Nicaraguan Contras. Investigation by the United States Department of Justice Office of the Inspector General, Central Intelligence Agency Office of Inspector General, and United States House Permanent Select Committee on Intelligence rejected the main charges.
== France ==
Illegal labs producing heroin were first discovered near Marseille, France, in 1937. These labs were run by Corsican gang leader Paul Carbone. For years, the Corsican underworld had been involved in the manufacturing and trafficking of heroin, primarily to the United States. It was this heroin network that eventually became known as "the French Connection". The Corsican Gang was protected by the CIA and the SDECE after World War II in exchange for working to prevent French Communists from bringing the Old Port of Marseille under their control.
== Golden Triangle (Southeast Asia) ==
During the Korean War, the first allegations of CIA drug trafficking surfaced after 1949, stemming from a deal whereby arms were supplied to Chiang Kai-shek's defeated generals in exchange for intelligence. Later in the same region, while the CIA was sponsoring a "Secret War" in Laos from 1961 to 1975, it was openly accused of trafficking heroin in the Golden Triangle area.
To fight its "Secret War" against the Pathet Lao communist movement of Laos, the CIA used the Miao/Meo (Hmong) population. Because of the war, the Hmong depended upon opium poppy cultivation for hard currency. The Plain of Jars had been captured by Pathet Lao fighters in 1964, which resulted in the Royal Lao Air Force being unable to land its C-47 transport aircraft on the Plain of Jars for opium transport. The Royal Laotian Air Force had almost no light planes that could land on the dirt runways near the mountaintop poppy fields. Having no way to transport their opium, the Hmong were faced with economic ruin. Air America, a CIA front organization, was the only airline available in northern Laos. Alfred McCoy writes, "According to several unproven sources, Air America began flying opium from mountain villages north and east of the Plain of Jars to CIA asset Hmong General Vang Pao's headquarters at Long Tieng."
Air America was alleged to have profited from transporting opium and heroin on behalf of Hmong leader Vang, or of "turning a blind eye" to the Laotian military doing it. This allegation has also been supported by former Laos CIA paramilitary Anthony Poshepny (aka Tony Poe), former Air America pilots, and other people involved in the war. It is portrayed in the movie Air America. Larry Collins alleged:
During the Vietnam War, U.S. operations in Laos were largely a CIA responsibility. The CIA's surrogate there was a Laotian general, Vang Pao, who commanded Military Region 2 in northern Laos. He enlisted 30,000 Hmong tribesmen in the service of the CIA. These tribesmen continued to grow, as they had for generations, the opium poppy. Before long, someone—there were unproven allegations that it was a Mafia family from Florida—had established a heroin drug refinery lab in Region Two. The lab's production was soon being ferried out on the planes of the CIA's front airline, Air America. A pair of BNDD (the predecessor of the U.S. Drug Enforcement Administration) agents tried to seize an Air America [aircraft]."
Further documentation of CIA-connected Laotian opium trade was provided by Rolling Stone magazine in 1968, and by Alfred McCoy in 1972. McCoy stated that:
In most cases, the CIA's role involved various forms of complicity, tolerance or studied ignorance about the trade, not any direct culpability in the actual trafficking ... [t]he CIA did not handle heroin, but it did provide its drug lord allies with transport, arms, and political protection. In sum, the CIA's role in the Southeast Asian heroin trade involved indirect complicity rather than direct culpability.
However, aviation historian William M. Leary, writes that Air America was not involved in the drug trade, citing Joseph Westermeyer, a physician and public health worker resident in Laos from 1965 to 1975, that "American-owned airlines never knowingly transported opium in or out of Laos, nor did their American pilots ever profit from its transport." Aviation historian Curtis Peebles also denies that Air America employees were involved in opium transportation.
=== CIA response ===
Following a 2009 FOIA request, the 2006 document "Undercover Armies: CIA and Surrogate Warfare in Laos" was released. Former CIA Operations Officer in Vietnam and CIA historian Thomas Ahern wrote, drawing from his own recollection, that local tribesmen being trained by the CIA were prohibited from carrying opium on U.S. chartered flights. Only large packages were inspected, so that small amounts of opium for local consumption might have been carried by individuals, but the prohibition of commercial traffic was unequivocal.
== United States ==
During a PBS Frontline investigation, DEA field agent Hector Berrellez said, "I believe that elements working for the CIA were involved in bringing drugs into the country ... I know specifically that some of the CIA contract workers, meaning some of the pilots, in fact were bringing drugs into the U.S. and landing some of these drugs in government military air bases. And I know so because I was told by some of these pilots that in fact they had done that."
Several journalists state that the CIA used Mena Intermountain Municipal Airport in Arkansas to smuggle weapons and ammunition to the Contras in Nicaragua, and drugs back into the United States. Some theories have claimed the involvement of political figures Oliver North, then vice president and former CIA director George H. W. Bush, and then Arkansas governor Bill Clinton.
The CIA's self-investigation, overseen by the CIA's inspector general, stated that the CIA had no involvement in or knowledge of any illegal activities that may have occurred in Mena. The report said that the agency had conducted a training exercise at the airport in partnership with another federal agency and that companies located at the airport had performed "routine aviation-related services on equipment owned by the CIA".
== Nicaragua ==
In 1986, the United States Senate Committee on Foreign Relations began investigating drug trafficking from Central and South America and the Caribbean to the United States. The investigation was conducted by the Sub-Committee on Terrorism, Narcotics, and International Operations, chaired by Senator John Kerry, so its final 1989 report was known as the Kerry Committee report. The Report concluded that "it is clear that individuals who provided support for the Contras were involved in drug trafficking, the supply network of the Contras was used by drug trafficking organizations, and elements of the Contras themselves knowingly received financial and material assistance from drug traffickers."
In 1996, Gary Webb wrote a series of articles published in the San Jose Mercury News, which investigated Nicaraguans linked to the CIA-backed Contras who had smuggled cocaine into the U.S. which was then distributed as crack cocaine into Los Angeles and funneled profits to the Contras. His articles asserted that the CIA was aware of the cocaine transactions and the large shipments of drugs into the U.S. by the Contra personnel and directly aided drug dealers to raise money for the Contras. The Los Angeles Times, The New York Times, and The Washington Post launched their own investigations and rejected Webb's allegations. In May 1997, The Mercury News executive editor Jerry Ceppos, who had approved the series, published a column that acknowledged shortcomings in the series reporting, editing, and production, while maintaining the story was correct "on many important points." Webb later published a book based on the series, Dark Alliance: The CIA, the Contras, and the Crack Cocaine Explosion. An internal CIA journal denounces continued support for Webb and echoing of his claims, saying one supporter "twists and misinterprets to conform to his preconceived notions."
== Mexico ==
In October 2013, the American television network Fox News alleged that CIA operatives were involved in the kidnapping and murder of DEA covert agent Enrique Camarena, because he was a threat to the agency's drug operations in Mexico in the 1980s. According to the network, this information was provided to them by multiple sources, specifically two former federal agents and an ex-CIA contractor in interviews. According to all three alleged sources the CIA was collaborating with drug traffickers bringing cocaine and marijuana into the United States, and using its share of the profits to finance the Contra rebels attempting to overthrow Nicaragua's Leftist Sandinista government. The CIA spokesman responding to the allegations called it "ridiculous" to suggest that the agency had anything to do with the murder of a US federal agent or the escape of his alleged killer.
=== Torture and murder of Kiki Camarena ===
A number of former DEA agents, CIA agents, Mexican police officers, and historians contend that the CIA was complicit in the murder of Drug Enforcement Administration agent Kiki Camarena in 1985. Between 2013 and 2015, the Mexican newspaper Proceso, journalist Jesús Esquivel, journalists Charles Bowden and Molly Malloy, and historians Russell and Silvia Bartley published investigative reports and books making the same allegation. They wrote that Camarena, like Mexican journalist Manuel Buendía, discovered that the CIA helped organize drug trafficking from Mexico into the United States in order to fund the anti-communist Contras in Nicaragua as a part of the Cold War. Historian Wil Pansters explained that US victory in the Cold War was more important to the CIA than the DEA's War on Drugs:Since the overriding concern of the CIA was the anti-Sandinista project, it trumped the DEA's task of combating drug trafficking, and covertly incorporated (or pressured) parts of the Mexican state into subservience. Buendía had found out about the CIA-contra-drugs-DFS connection, which seriously questioned Mexican sovereignty, while Camarena learned that the CIA had infiltrated the DEA and sabotaged its work so as to interfere with the clandestine contra-DFS-traffickers network. They knew too much and were eliminated on the orders of the U.S. with Mexican complicity. Later official investigations attempted to limit criminal responsibility to the dirty connections between drug traffickers, secret agents and corrupt police, leaving out the (geo)political ramifications.
In 2019, the United States Department of Justice began reinvestigating Camarena's murder, and in 2020, Amazon Studios released a documentary, The Last Narc, supporting the allegations, and implicating Félix Rodríguez. The CIA has said the allegations are untrue. In a blog post, Camarena biographer Elaine Shannon described the allegations as a "Deep State conspiracy theory," and interviewed former DEA agent Jack Lawn, who agreed with her.
The notion of CIA involvement in Camarena's murder has received wide currency in Latin America.
== Honduras ==
The Honduran drug lord Juan Matta-Ballesteros was the owner of SETCO, an airline which the Nicaraguan Contras used to covertly transport military supplies and personnel in the early 1980s. Writers such as Peter Dale Scott and Jonathan Marshall have suggested that the U.S. government's desire to conceal or protect these clandestine shipments led it to close the DEA office in Honduras when an investigation began into SETCO, allowing Matta-Ballesteros to continue and expand his trafficking.
== Venezuela ==
In 1990, a failed CIA anti-drug operation in Venezuela resulted in at least a ton of cocaine being smuggled into the United States and sold on the streets. The incident, which was first made public in 1993, was part of a plan to assist an undercover agent to gain the confidence of a Colombian drug cartel. The plan involved the unsupervised shipment of hundreds of pounds of cocaine from Venezuela. The drug in the shipments was provided by the Venezuelan anti-drug unit which was working with the CIA, using cocaine seized in Venezuela. The shipments took place despite the objections of the U.S. DEA. When the failed plan came to light, the CIA officer in charge of the operation resigned, and his supervisor was transferred. The CIA issued a statement on the incident saying there was "poor judgment and management on the part of several C.I.A. officers".
In addition, the former Venezuelan anti-narcotics chief General Ramon Guillen Davila and his chief civilian aide were both indicted in connection with the shipments. Because Venezuela does not extradite its citizens, Guillen was not tried in the U.S., but his civilian aide was arrested while in the United States and sentenced to 20 years.
== Afghanistan ==
Alfred McCoy has argued that the CIA had fostered heroin production in Afghanistan for decades to finance operations aimed at containing the spread of communism, and later to finance operations aimed at containing the spread of the Islamic state. McCoy alleges that the CIA protects local warlords and incentivizes them to become drug lords. In his book Politics of Heroin, McCoy alleges CIA complicity in the global drug trade in Afghanistan, Southeast Asia, Central America, and Colombia, arguing that the CIA follows a similar pattern in all their drug involvement. McCoy has also written that during the 1980s "to fight the Soviet occupation of Afghanistan, the CIA, working through Pakistan's Inter-Services Intelligence, backed Afghan warlords who used the Agency's arms, logistics, and protection to become major drug lords."
According to The New York Times, in 2006, the US Ambassador in Kabul, the CIA station chief and MI6/SIS's station chief met with Afghan President Hamid Karzai, to address allegations regarding his brother, Ahmed's involvement in the drug trade, hoping that he would agree to expel his brother from Afghanistan. Before agreeing to take such action, Karzai demanded clear evidence of his brother's involvement be presented—evidence which the US and the UK were either unwilling or unable to provide.
Then in October 2009, the New York Times published an article by Dexter Filkins, Mark Mazzetti, and James Risen who reported that unnamed former and current American officials had said Ahmed Wali Karzai had received regular payments from the CIA for eight years—starting shortly after his brother was elected President—and was involved in the trafficking of opium in Afghanistan. Ahmed Wali Karzai denied the allegations stating that he had provided intelligence to the United States but was not compensated. Mahmud Karzai told Gerald Posner: "This is being coordinated by the ISI (Pakistani intelligence service). They have been behind the assassinations of several provincial leaders who are against the Taliban. And my brother is the last major obstacle to them in the south. If they remove Ahmed Wali, the Taliban will fill the void." A CIA spokesman said: "No intelligence organization worth the name would ever entertain these kind of allegations." In an article for Washington Decoded, former CIA operations officer Merle Pribbenow said, like claims leveled toward former South Vietnamese Lieutenant General Đặng Văn Quang, the allegations against Ahmed Wali Karzai appeared to be "vague rumors unsupported by solid evidence" and he cautioned readers about accepting news based solely on anonymous sources and unsubstantiated rumors.
== In popular media ==
The 2014 movie Kill the Messenger depicted actor Jeremy Renner as Gary Webb.
In the 2015 movie Sicario, actress Emily Blunt portrays a FBI special agent who joins a government task force to bring down a Mexican drug cartel, only to discover that her CIA counterparts' true goal is to restore control of the drug trade to a single Colombian-run business.
The 2017 film American Made is a fictionalized telling of the story of Barry Seal, a pilot and Medellín Cartel drug smuggler who based his operations in Mena, Arkansas.
The 2017 FX television show Snowfall features CIA involvement in introducing cocaine and crack to Los Angeles, California.
Alternative heavy metal band System of a Down's "Prison Song"" from its 2001 album Toxicity touches upon CIA drug exchange with the line, "drug money is used to rig elections and train brutal corporate sponsored dictators around the world".
== See also ==
CIA transnational anti-crime and anti-drug activities
Air America (airline), an American passenger and cargo airline that was covertly owned and operated by the CIA from 1950 to 1976 and was allegedly associated with drug smuggling in Laos
Air America (book), a non-fiction book about the airline
Air America (film), an action comedy film loosely based on the history of the airline and the book
Nugan Hand Bank, an Australian merchant bank that collapsed in 1980 with alleged involvement with the CIA, drug trafficking, and other illegal activities
Anthony Poshepny, a CIA officer who accused the Laotian Major General Vang Pao of using the war, and CIA assets, to enrich himself through the opium trade
Compromised-Clinton, Bush and the CIA, by Terry Reed and John Cummings. During Vietnam, Terry said he was a CIA pilot running drugs from Laos. Later at Mena Arkansas he said he was assigned to train the sons of rich South Americans to fly freighters to supply weapons to the Nicaraguan Contras. Years later, he claimed he (as a CIA contractor) ran a machinery import business in Mexico that helped distribute heroin to Mexico and the United States.
Ike Atkinson, a former US Army sergeant and convicted drug trafficker, thought to have been a major figure in smuggling heroin into the United States from c. 1968 to 1975
Khun Sa
The Politics of Heroin in Southeast Asia, a 1972 book with allegations of CIA complicity in the heroin trade
Eclipse of the Assassins
Project MKULTRA
War on drugs
== References ==
== Further reading ==
Scott, Peter Dale; Marshall, Jonathan (1998). Cocaine Politics: Drugs, Armies, and the CIA in Central America. University of California Press. ISBN 0-520-21449-8.
Scott, Peter Dale (2003). "11, "Opium, the China Lobby, and the CIA"". Drugs, oil, and war: the United States in Afghanistan, Colombia, and Indochina. Rowman & Littlefield. ISBN 978-0-7425-2522-1.
Kruger, Henrik. (1980). The Great Heroin Coup: Drugs, Intelligence, and International Fascism. South End Press. ISBN 0-89608-031-5.
Kwitny, Jonathan (1988). The Crimes of Patriots: A True Tale of Dope, Dirty Money, and the CIA. Touchstone Books. ISBN 978-0-671-66637-8.
Levine, Michael (1993). The Big White Lie: The Deep Cover Operation That Exposed the CIA Sabotage of the Drug War. Thunder's Mouth Pr. ISBN 978-1-56025-084-5.
McCoy, Alfred W.; Read, Kathleen B. (1972). The Politics of Heroin in Southeast Asia. Harper & Row. ISBN 0060129018. Archived from the original on February 16, 2015. (The link is to the complete text of this book.)
McCoy, Alfred W. (2003). The Politics of Heroin: CIA Complicity in the Global Drug Trade, Afghanistan, Southeast Asia, Central America, Columbia. Lawrence Hill & Co. ISBN 1-55652-483-8.
Webb, Gary (1999). Dark Alliance: CIA, the Contras and the Crack Cocaine Explosion. Seven Stories Press, U.S. ISBN 1-888363-93-2.
Cockburn, Alexander; St-Clair, Jeffrey (1998). Whiteout: The CIA, Drugs, and the Press. Verso. ISBN 9781859841396.
=== CIA and DOJ Reports ===
Overview of CIA/IG Investigation (January 29, 1998)—A short summary of The Inspector General's Report of Investigation regarding allegations of connections between CIA and the Contras in cocaine trafficking to the United States.
Report of Investigation—Volume I: The California Story (January 29, 1998) —The Inspector General's Report of Investigation regarding allegations of connections between CIA and the Contras in cocaine trafficking to the United States. Volume I: The California Story.
Report of Investigation – Volume II: The Contra Story (October 8, 1998)—The Inspector General's Report of Investigation regarding allegations of connections between CIA and the Contras in cocaine trafficking to the United States. Volume II: The Contra Story.
USDOJ/OIG Special Report. The CIA-Contra-Crack Cocaine Controversy: A Review of the Justice Department's Investigations and Prosecutions (December, 1997)
== External links ==
Guns, Drugs, and the CIA—Frontline
Congressional Testimony of Peter Kornbluh | Wikipedia/Allegations_of_CIA_drug_trafficking |
The Financial Action Task Force (FATF), also known by its French name, Groupe d'action financière (GAFI), is an intergovernmental organisation founded in 1989 on the initiative of the G7 to develop policies to combat money laundering and to maintain certain interest. In 2001, its mandate was expanded to include terrorism financing. The FATF Secretariat is administratively hosted at the OECD in Paris, but the two organisations are separate.
The objectives of FATF are to set standards and promote effective implementation of legal, regulatory and operational measures for combating money laundering, terrorist financing and other related threats to the integrity of the international financial system. FATF is a "policy-making body" that works to generate the necessary political will to bring about national legislative and regulatory reforms in these areas. FATF monitors progress in implementing its Recommendations through "peer reviews" ("mutual evaluations") of member countries.
Since 2000, FATF has maintained the FATF blacklist (formally called the "Call for action") and the FATF greylist (formally called the "Other monitored jurisdictions"). The blacklist has led financial institutions to shift resources and services away from the listed. This in turn has motivated domestic economic and political actors in the listed countries to pressure their governments to introduce regulations compliant with the FATF.
== History ==
FATF was formed at the 1989 G7 Summit in Paris to combat the growing problem of money laundering. The task force was charged with studying money laundering trends, monitoring legislative, financial and law enforcement activities taken at the national and international level, reporting on compliance, and issuing recommendations and standards to combat money laundering. At the time of its formation, FATF had 16 members, which by 2023 had grown to 40. In its first year, FATF issued a report containing forty recommendations to more effectively fight money laundering. These standards were revised in 2003 to reflect evolving patterns and techniques in money laundering.
The mandate of the organisation was expanded in 2001 to include terrorist financing following the September 11 terror attacks.
== FATF Recommendations ==
=== Creation and ongoing maintenance ===
Together, the Forty Recommendations on Money Laundering and eight (now nine) Special Recommendations on Terrorism Financing set the international standard for anti-money laundering measures and combating the financing of terrorism and terrorist acts. They set out the principles for action and allow countries a measure of flexibility in implementing these principles according to their particular circumstances and constitutional frameworks. Both sets of FATF Recommendations are intended to be implemented at the national level through legislation and other legally binding measures. There are multiple groups to organise the Recommendations; AML/CFT Policies and Coordination, Money Laundering and Confiscation, Terrorist Financing and Financial Proliferation, Preventive Measures, Transparency and Beneficial Ownership of Legal Persons and Arrangements, Powers and Responsibilities of Competent Authorities and other Institutional Measures, and International Cooperation.
In February 2012, the FATF codified its recommendations and Interpretive Notes into one document that maintains SR VIII (renamed Recommendation 8), and also includes new rules on weapons of mass destruction, corruption and wire transfers (Recommendation 16, commonly known as the “travel rule”).
In October 2018, the FATF updated Recommendation No. 15, expanding its reach to include operations related to virtual assets. It urged its member countries to ensure that providers of virtual asset services are regulated for AML/CFT objectives and licensed or registered. Additionally, they should be under robust systems for supervision assurance and compliant with the FATF recommendations.
In June 2019, the FATF released its first guidance on the risk-based approach for virtual assets and virtual asset service providers. This guidance offers recommendations on how member jurisdictions should regulate cryptocurrency businesses, placing anti-money laundering and countering the financing of terrorism (AML/CFT) obligations on VAs and VASPs. It also extended Recommendation 16 to VASPs.
This guidance was updated on March 19 and October 2021.
==== Forty recommendations on money laundering ====
The FATF's Forty Recommendations on Money Laundering of 1990 are the primary policies issued by FATF and the Nine Special Recommendations (SR) on Terrorism Financing (TF). The Recommendations are seen globally as the world standard in anti-money laundering as well many countries have committed to putting the Forty Recommendations in place. The Recommendations cover the criminal justice system and law enforcement, international cooperation, and the financial system and its regulation. The FATF completely revised the Forty Recommendations in 1996 and 2003. By 1996 the Recommendations had to be updated to include more than just drug-money laundering, as well as to keep up with changing techniques. The 2003 Forty Recommendations require states, among other things, to:
Implement relevant international conventions
Criminalise money laundering and enable authorities to confiscate the proceeds of money laundering
Implement customer due diligence (e.g., identity verification), record keeping and suspicious transaction reporting requirements for financial institutions and designated non-financial businesses and professions
Establish a financial intelligence unit to receive and disseminate suspicious transaction reports, and
Cooperate internationally in investigating and prosecuting money laundering
==== Nine Special Recommendations on Terrorism Financing ====
The FATF has issued Special Recommendations on Terrorist Financing. In October 2001 the FATF issued the original eight Special Recommendations on Terrorism Financing, following the September 11 attacks in the United States. Among the measures, Special Recommendation VIII (SR VIII) specifically targeted non-profit organisations. This was followed by the International Best Practices Combating the Abuse of Non-Profit Organisations in 2002, released one month before the U.S. Department of Treasury's Anti-Terrorist Financing Guidelines, and the Interpretive Note for SR VIII in 2006. A ninth Special Recommendation was added later. In 2003 the Recommendations, as well as the 9 Special Recommendations were adjusted for the second time.
=== Compliance mechanism ===
In February 2004 (Updated as of February 2009) the FATF published a reference document Methodology for Assessing Compliance with the FATF 40 Recommendations and the FATF 9 Special Recommendations. The 2009 Handbook for Countries and Assessors outlines criteria for evaluating whether FATF standards are achieved in participating countries. FATF evaluates a country's performance based on its assessment methodology that covers: 1. technical compliance, which is about the legal and institutional framework and the powers and procedures of the competent authorities, and 2. effectiveness assessment, which is about the extent to which the legal and institutional framework is producing the expected results.
There are many differences between countries dealing with their legal and financial system, which is taken into consideration by the FATF. There is a set minimum of actions that meet a standard, that all countries can use regarding their own situation. This standard covers all actions that a nation should take within its regulatory systems and its criminal justice systems as well as the preventive measures that should be taken by specified businesses, professions, and institutions.
For non-profit organisations (NPOs) there has been a command for more financial transparency, to make sure that they do not become easier for terrorist organisations to launder money through the organisations. This hypothesis was thought of by intergovernmental organisations. These intergovernmental organisations include the World Bank, the Organisation for Economic Co-operation and Development and the International Monetary Fund. NPOs are put under surveillance, especially when they are associated with "suspect communities" or if they are based or working in zones of conflict.
FATF data is a key indicator of the quality of AML/CFT systems in the Basel AML Index, a money laundering and terrorist financing risk assessment tool developed by the Basel Institute on Governance.
There are still compliance issues in areas that might afford exploitative opportunities for transnational crime and terrorist networks. This can have detrimental effects on a country's national security through increasing risks of money laundering and financing of terrorism as well as wastage due to the implementation of inappropriate regulatory measures. The objective is to increase mitigation strategies that would enable scarce resources in fighting money laundering and terrorism financing threats.
The FATF follows strict criteria to identify potential threats.
=== Black or greylisting of non-compliant nations ===
In addition to FATF's "Forty plus Nine" Recommendations, in 2000 FATF issued a list of "Non-Cooperative Countries or Territories" (NCCTs), commonly called the FATF Blacklist. This was a list of 15 jurisdictions that, for one reason or another, FATF members believed were uncooperative with other jurisdictions in international efforts against money laundering (and, later, terrorism financing). Typically, this lack of cooperation manifested itself as an unwillingness or inability (frequently, a legal inability) to provide foreign law enforcement officials with information relating to bank account and brokerage records, and customer identification and beneficial owner information relating to such bank and brokerage accounts, shell corporations, and other financial vehicles commonly used in money laundering. All remaining Non-Cooperative Countries and Territories in the NCCT initiative were delisted in October 2006, however, FATF continues to maintain a "blacklist" of "High Risk" jurisdictions and a "greylist" of "Jurisdictions Under Increased Monitoring", and issues updates as countries on High-risk and non-cooperative jurisdictions list have made significant improvements in standards and cooperation. The FATF also issues updates to identify additional jurisdictions that pose Money Laundering/Terrorist Financing risks.
The FATF surveyed 26 jurisdictions to check their ability and willingness to cooperate with other countries in the international fight against money laundering. The review contained the summaries of these surveys. Fifteen jurisdictions were branded "non-cooperative countries or territories", because of the high number of harmful practices identified in these jurisdictions.
As of February 2025, countries in the blacklist are Iran, Myanmar and North Korea. Countries and territories in the grey list are Algeria, Angola, Bulgaria, Burkina Faso, Cameroon, Côte d'Ivoire, Croatia, Democratic Republic of the Congo, Haiti, Kenya, Laos, Lebanon, Mali, Monaco, Mozambique, Namibia, Nepal, Nigeria, South Africa, South Sudan, Syria, Tanzania, Venezuela, Vietnam, and Yemen.
== Members and affiliate organisations ==
As of October 2023, FATF has 38 countries as full members. However, through several associated regional bodies, the FATF network comprised 187 countries in total, as of 2012. The FATF also works in close cooperation with several international and regional organisations. Countries are subjected to evaluation by FATF to see that they are upholding laws and regulations enforced by FATF.
=== Full members ===
As of 2023 The FATF currently comprises 38 member jurisdictions and two regional organisations, representing most major financial centres in all parts of the globe:
Regional organisations
Countries and other jurisdictions
=== FATF-style regional bodies ===
As of 2023, there are 9 "FATF-style regional bodies" that are associate members of the FATF:
Countries that are not full FATF members but are members of the FATF-style regional bodies are entitled to attend FATF meetings as individual member delegates of the regional bodies and to intervene on policy and operational issues.
=== Observer members ===
There are 28 international organisations with the "FATF Observer" status. These include the International Monetary Fund, the UN with six expert groups and the World Bank and the OECD. All the observer organisations have anti-money laundering as one of their tasks. The observer organisations include:
== Effects of FATF ==
The FATF has been characterized as effective in shifting laws and regulations to combat illicit financial flows. FATF incentivizes stricter regulations through its public noncomplier list, which leads financial institutions to shift resources and services away from the countries on the blacklist. This in turn motivates domestic economic and political actors in the listed countries to pressure their governments to introduce regulations that are compliant with the FATF.
As of 2012, the effect of the FATF Blacklist has been significant, and arguably has proven more important in international efforts against money laundering than the FATF Recommendations. While, under international law, the FATF Blacklist carries with it no formal sanction, in reality, jurisdictions placed on the FATF Blacklist often face intense financial pressure.
FATF has made it difficult for non-governmental organisations (NGOs) in many countries to access funds to aid in relief situations and conduct other important civil society functions due to the misinterpretation of FATF criteria by governments. The unintended consequences of the misinterpretation of FATF Recommendation 8 on non-profit organisations have impacted NGOs, particularly those in the Global South extending well beyond civil society located in Middle Eastern and terror-ridden countries. In 2023, FATF released new guidance on interpretation of Recommendation 8 relating to non-profits, to better prevent misuse of its standards to restrict legitimate civil society operations.
In a 2020 paper, Ronald Pol stated that while the FATF has been very successful in getting its policies adopted worldwide, the actual impact of those policies has been rather small: according to his estimates, less than 1% of illegal profits are seized, with the costs of implementing the policies being at least one hundred times larger. Pol contends that industry and policymakers consistently ignore this, instead evaluating the policies based on largely irrelevant success metrics.
== See also ==
Hawala
Hundi
Informal value transfer system
Politically exposed person
Remittance
White-collar crime
Wolfsberg Group
== References ==
== Further reading ==
Findley, Michael G.; Daniel L. Nielson and J. C. Sharman (Fall 2013). "Using Field Experiments in International Relations: A Randomized Study of Anonymous Incorporation". International Organization, Vol. 67, No. 4, pp. 657–693. JSTOR 43282083.
Müller, Sebastian R. (2006). Hawala: An Informal Payment System and Its Use to Finance Terrorism, VDM Verlag, ISBN 978-3-86550-656-6
== External links ==
Media related to Financial Action Task Force on Money Laundering at Wikimedia Commons
Official website | Wikipedia/Financial_Action_Task_Force |
A design museum is a museum with a focus on product, industrial, graphic, fashion and architectural design.
Many design museums were founded as museums for applied arts or decorative arts and started only in the late 20th century to collect design.
The first museum of this kind was the Victoria and Albert Museum in London. In Germany the first museum of decorative arts was the Deutsches-Gewerbe-Museum zu Berlin (now Kunstgewerbemuseum), founded in 1868 in Berlin.
Also some museums of contemporary or modern art have important design collections, such as the MoMA in New York and the Centre Pompidou in Paris. A special concept has been realised in the Pinakothek der Moderne in Munich, in which four independent museums cooperate, one of them being Die Neue Sammlung – the largest design museum in the world.
Today corporate museums like the Vitra Design Museum, Museo Alessi or Museo Kartell play an important role.
== List of design museums ==
21 21 Design Sight, Tokyo, Japan
ADI Design Museum, Milan, Italy
Archivo Diseño y Arquitectura, Mexico City
Art, Design & Architecture Museum (AD&A), University of California, Santa Barbara, Goleta, California
Bauhaus Archive, Berlin, Germany
Bröhan Museum, Berlin, Germany
Chicago Athenaeum, Galena, Illinois, USA
Cooper Hewitt, Smithsonian Design Museum, New York, USA
Design Exchange, Toronto, Canada
Design Museum of Barcelona, Spain
Design Museum Brussels (former Art & Design Atomium Museum), Belgium
Design Museum of Chicago, Chicago, USA
Museum dan Rumah Desain Runa, Bali, Indonesia
Design Museum Dedel, Den Haag, Netherlands
Design Museum Den Bosch, Netherlands
Design Museum Dharavi, India
Design Museum Gent, Belgium
Design Museum, Helsinki
Design Museum Holon, Tel Aviv, Israel
Design Museum, London, UK
Design Museum of Thessaloniki, Greece
Danish Museum of Art & Design, Copenhagen, Denmark
Die Neue Sammlung, Munich, Germany
HKDI Gallery (Hong Kong Design Institute), Hong Kong
Icelandic Museum of Design and Applied Art, Garðabær, Iceland
International Design Centre, Nagoya, Japan
Kunstgewerbemuseum Berlin, Germany
Leipzig Museum of Applied Arts, Germany
Ljubljana Museum of Architecture and Design, Slovenia
M+ Museum, Hong Kong
Museo del Objeto del Objeto, Mexico City
Musée des Arts Décoratifs, Paris, France
Musée des Arts Décoratifs et du Design, Bordeaux, France
Musée des Arts et Métiers, Paris, France
Museo Nacional de Artes Decorativas, Madrid, Spain
Museum of Applied Arts (Belgrade), Serbia
Museum of Applied Arts (Budapest), Hungary
Museum of Arts and Design, New York, USA
Museum of Craft and Design, San Francisco, USA
Museum für angewandte Kunst Frankfurt, Germany
Museum für angewandte Kunst Cologne, Germany
Museum für angewandte Kunst Wien, Vienna, Austria
Museum of Contemporary Design and Applied Arts (MUDAC), Lausanne, Switzerland
Museum für Gestaltung Zürich, Switzerland
Museum für Kunst und Gewerbe Hamburg, Germany
Museum of Decorative Arts in Prague, Czech Republic
Museum of Design Atlanta, Atlanta, Georgia, USA
Museum of Domestic Design and Architecture, London, UK
National Museum of Art, Architecture and Design, Oslo, Norway
Powerhouse Museum, Sydney, Australia
Röhsska Museum, Gothenburg, Sweden
Swedish Centre for Architecture and Design, Stockholm, Sweden
Swedish Design Museum (virtual), Sweden
SONS Museum, a museum dedicated to shoe design, Kruishoutem, Belgium
Singapore City Gallery, Singapore
Red Dot Design Museum, Essen, Germany
Red Dot Design Museum (Singapore)
Stedelijk Museum, Amsterdam, Netherlands
Stedelijk Museum, Breda, Netherlands
Stieglitz Museum of Applied Arts, Saint Petersburg, Russia
Taiwan Design Museum, Taipei, Taiwan
Triennale di Milano, Milan, Italy
Victoria and Albert Museum (V&A), London, UK
V&A Dundee, Dundee, Scotland, UK
Vitra Design Museum, Weil am Rhein, Germany
Wolfsonian-FIU, Miami Beach, Florida, USA
Z33, Hasselt, Belgium
== References ==
== External links ==
"design museums blog" with information on design museums
Map of design museums around the world | Wikipedia/Design_museums |
Design prototyping in its broader definition comprises the actions to make, test and analyse a prototype, a model or a mockup according to one or various purposes in different stages of the design process. Other definitions consider prototyping as the methods or techniques for making a prototype (e.g., rapid prototyping techniques), or a stage in the design process (prototype development, prototype or prototyping). The concept of prototyping in design disciplines' literature is also related to the concepts of experimentation (i.e., an iterative problem-solving process of trying, failing and improving), and Research through Design (RtD) (i.e., designers make a prototype with the purpose of conducting research and generating knowledge while trying it, rather than aiming to improving it to become a final product).
== Background ==
Initial references to the concept of prototyping in design could be traced to the proceedings of the Conference on Design Methods in 1962:
"As you come down in scale, it is much more likely that you will be able to mass produce the object, and therefore be able to make a prototype, test it and try it out and explore it."
In 1968, Bruce Archer, a relevant figure in the "Design Methods Movement" describes the design process. One of the stages of the process is called "Prototype development" and it indicates activities to build and test a prototype. Thus, it would be possible to say that from a design methods' perspective, prototyping recalls a process in which a prototype is built, tried out and tested. In the same line, additional references to prototyping can be found in later editions of the Design Research Society's Conferences. For example, referring to build models and use them to consult people out of the design team, review the model and make decisions on how to modify the design proposal; or describing modelling (creating a model) and model simulation.
However, one of the first documented uses of the term prototyping linked to a design process appears in 1983 in A systematic look at prototyping in the field of information systems and software development. The work of Floyd was inspired by the discussions among the scholars who were preparing the Working Conference on Prototyping. It focuses on prototype as a process, rather than the artefact and how prototyping could be applied to the full solution (or product) or parts of it seeking to improve the final output. Although this work was not developed within the design discipline, it provides a comprehensive characterisation of prototyping by defining its steps, purposes and strategies. Moreover, it serves as a referent to further studies of design prototyping.
Later, around the year of 1990, the availability of methods for rapidly manufacturing models and prototypes stimulated the publication of a great body of literature dedicated to rapid prototyping techniques and technologies (e.g., 3D printing). Technologies for additive manufacturing (i.e., adding material) or substractive manufacturing (i.e., removing material) together with the use of software for computer-aided design (CAD), leveraged prototype building but also the fabrication of products in limited numbers.
Along the years, further efforts have been dedicated to characterising prototyping in design disciplines in the fields of interaction design, experience design, product design and service design, as well as in product-design-related fields such as engineering/mechanical design. In 2000, designers from IDEO described experience prototyping, introducing types of design representations and methods that allow to simulate aspects of an interaction that people experience by themselves. Experience prototyping can combine various types of prototypes such as spaces, products and interfaces to resemble what the real experience could be like. Around the year of 2010, studies were developed to examine the prototyping of services theorising from the growing practice of service design, which later in 2018 were also used as a reference for service design practitioners.
== Prototyping cycle ==
Prototyping is developed in an iterative cycle of making, testing and analysing which allows to examine dimensions of a solution before its future implementation, anticipating to possible issues and improving them earlier in the process. This cycle can be portrayed the following steps:
Preparation: to decide the aims of prototyping, define questions and assumptions that are going to be examined, identify the participants of the prototyping sessions and the dimensions of the prototype that are going to be tested.
Making: some or various dimensions will be represented in a prototype (e.g., material, form or function) employing an appropriate depending on the purpose. The relevance on making on design has been increasing in the last years and transforming while new design disciplines emerge. For instance, whilst sketches were previously another category of visual design representations, today they could also be considered prototypes in service design.
Testing: the prototyping session develops in a defined setup with certain characteristics of space and environment and will follow a method to gather feedback.
Analysing: the results of the testing will be integrated into the solution and updated in the following prototype versions.
One example of this cycle could be the design of a digital interface in the early stages of the process applying paper prototyping. In this case, prototyping may seek to explore and evaluate multiple alternatives of ideas with the users as fast and cheap as possible, before investing time to program it. Thus, the prototypes will represent the structure of the interface by using simple forms and text to indicate the elements (1). A common technique for creating prototypes of digital interfaces would be to sketch wireframes in paper (2). The team will meet with a potential user and the wireframes will be presented by the design researcher. The user will simulate to click the elements and explain the actions that intends to do while moving to other sheets that represent other screens in the navigation flow (3). The feedback gathered will be used to make decisions on the aspects that need to be modified and the layout of the interface will be updated (4).
== Characteristics of prototyping ==
To prepare for prototyping, some aspects need to be decided. For this purpose, it is useful to individualise and consider various characteristics that will allow identifying how prototyping should be developed according to the design needs. In this regard, the prototyping framework proposed by Blomkvist and Holmid could provide some guidelines. As a result of a literature review, they identify a set of characteristics which are:
=== Position in the process ===
Whilst for some scholars prototyping was happening in a particular stage of the design process, the importance of prototyping has been gaining relevance as a continuous activity since the early stages of the process. Considering in which moment of the process prototyping is going to be developed will guide decisions on its purpose and further characteristics of prototyping.
=== Purpose ===
Prototyping can be developed according to different aims of the design process that influence decisions such as what variables of the prototype are going to be examined and who is going to be involved in the testing session. For example, in the early stages of the process, the need could be to explore various ideas within the design team and prototypes may be created fast and with little resources, while at the end of the process the functionality of the solution may be evaluated with future users so the prototype would largely resemble its final version.
Some of the purposes of prototyping identified by different authors are:
=== Stakeholder ===
A prototyping session can involve a variety of people related to the solution. Internal to the organisation, the participants could range from the members of the design team to colleagues from other departments and managers. External to the organisation, prototyping could involve future users and clients, and representatives from other organisations. The selection of the participants would depend on the purposes of prototyping. For instance, a prototyping session for exploration could be developed internally with colleagues in order to get quick feedback about initial design proposals. Another example would be to involve users in co-design prototyping sessions in order to explore proposals directly with future users.
=== Activity ===
The activity refers to the method that would be used for testing a prototype, the context in which it is going to occur, and the strategies for testing in relation to what would be the real conditions of use of the solution.
=== Prototype ===
Prototypes can represent one component of a future solution such as "(Inter)actions, service processes, experiences, physical objects, environments, spaces, architecture, digital artifacts and software, ecosystems, [or] (business) value" or comprise various of these components.
Moreover, a prototype can reflect one or multiple dimensions of the future solution and a variety of aspects could be considered. A simple approach would be to think on the fidelity, meaning how close the prototype resembles to the final solution (blom)(stick). More comprehensive approaches can be considered through multiple dimensions. For instance, Houde and Hill describe the “role” (i.e., functionality for the user), “look and feel” (i.e., sensory, and experiential aspects), “implementation” (i.e., performance of the solution). Lim, Stolterman and Tenenberg propose a classification of prototypes according to “filtering dimensions: functionality, interactivity, and spatial structure"; and “manifestation dimensions:materials, resolution, and scope". They suggest these dimensions can be pondered in order to decide how the prototype should be.
"The best prototype is one that, in the simplest and the most efficient way, makes the possibilities and limitations of a design idea visible and measurable”
== See also ==
Prototype
Model
Mockup
Rapid prototyping
Design methods
Interaction design
User experience design
Product design
Service design
Software prototyping
Participatory design - co-design
== References == | Wikipedia/Design_prototyping |
Design-based learning (DBL), also known as design-based instruction, is an inquiry-based form of learning, or pedagogy, that is based on integration of design thinking and the design process into the classroom at the K-12 and post-secondary levels. Design-based learning environments can be found across many disciplines, including those traditionally associated with design (e.g. art, architecture, engineering, interior design, graphic design), as well as others not normally considered to be design-related (science, technology, business, humanities). DBL, as well as project-based learning and problem-based learning, is used to teach 21st century skills such as communication and collaboration and foster deeper learning.
Deeper learning is supported when students design and create an artifact that requires understanding and application of knowledge. DBL activity supports iteration as students create, assess, and redesign their projects. The work's complexity often requires collaboration and specialized roles, providing students with the opportunity to become "experts" in a particular area. Design projects require students to establish goals and constraints, generate ideas, and create prototypes through storyboarding or other representational practices. Robotics competitions in schools are popular design-based learning activities, wherein student teams design, build and then pilot their robots in competitive challenges.
Design-based learning was developed in the 1980s by Doreen Nelson, a professor at California State Polytechnic University, Pomona and the Art Center College of Design. Her findings suggested that kinesthetic problem-solving helps students acquire, retain, and synthesize information in practical ways.
== Design process ==
The design process is an iterative process that has a variety of sequential steps:
investigate context
identify needs
develop criteria
generate alternatives
select alternative
prototype/test
produce
evaluate
A similar approach is the ADDIE Model of instructional design, a framework of generic processes used by instructional designers and training developers. It represents a descriptive guideline with five distinct phases:
Analysis
Design
Development
Implementation
Evaluation
== Results ==
Positive benefits of the design-based learning approach have been observed, including student-based learning where students (often) identify their project's needs, develop their own ideas, and engage in a larger range of thinking than with the traditional scripted inquiry model. The results from the 2008 study by Mehalik et al. found significant improvement in student performance using the DBL model compared to the scripted model. A 1998 study (Fraser, Fraser & Tobin, 1991) suggest that DBL has the potential to increase students' desire to learn, enhance success in science class, and increase interest in science topics. Students were observed to be engaged in DBL and the lower-achieving students were able to explain concepts at higher levels than previously observed by their teacher. In-depth experience in design activities and creation of meaningful outcomes in technology were observed in terms of the finished product, documentation, and reflection.
Significant benefits of implementing DBL has been observed in the areas of math and science (Darling-Hammond et al., 2008). Research has found that students who participate in learning by design projects have a more systematic understanding of a system's parts and functions that control groups (Hmelo, Holton, & Kolodner, 2000).
A 2000 study (Hmelo, Holton, and Kolodner) found that the design project led to better learning outcomes and included deeper learning than the traditional learning approach. The researchers also noted that the students developed greater understanding of complex systems. The study found that in using DBL, both higher-achieving and lower-achieving students showed strong evidence of progress in learning the targeted concepts, students were able to apply key concepts in their work, and there were positive effects on motivation and sense of ownership over work product by both groups and individual students.
== Implementation ==
The teaching of 21st century skills is more effective when teachers gain expertise in both the practice and the teaching of these skills, in effect becoming successful 21st century learners in the areas of: communication and collaboration amongst teachers and with students; being flexible with new classroom dynamics; fostering independent student learning; adapting teaching and learning styles to new pedagogical approaches.
Challenges to implementing DBL include developing the skills of the instructors:
teachers' ability to select topics and activities that support, and benefit from, differing viewpoints and students' real-world experiences
selecting students who will work well together
setting of effective ground rules to ensure equal opportunities to participate,
encouraging multiple strategies to foster full participation for all members of a group of team.
== See also ==
21st century skills – Skills identified as being required for success in the 21st century
Design thinking – Processes by which design concepts are developed
Problem-based learning – Learner-centric pedagogy
Project-based learning – Learner centric pedagogy
Organizational learning
STEM fields – Group of academic disciplines
== References ==
Fraser, B. J., & Tobin, K.: Combining qualitative and quantitative methods in classroom environment research. In B. J. Fraser & H. J. Walberg (Eds.), Educational environments: Evaluation, antecedents, and consequences (pp. 271–290). Oxford, UK: Pergamon Press. 1991.
== External links ==
Design Based Learning
Design Based Learning for STEM
Education in the new millennium: the case for design-based learning, International Council of Societies of Industrial Design
About Design-Based Learning, Cal Poly Pomona Archived 2015-03-05 at the Wayback Machine | Wikipedia/Design-based_learning |
A design is the concept or proposal for an object, process, or system. The word design refers to something that is or has been intentionally created by a thinking agent, and is sometimes used to refer to the inherent nature of something – its design. The verb to design expresses the process of developing a design. In some cases, the direct construction of an object without an explicit prior plan may also be considered to be a design (such as in arts and crafts). A design is expected to have a purpose within a specific context, typically aiming to satisfy certain goals and constraints while taking into account aesthetic, functional and experiential considerations. Traditional examples of designs are architectural and engineering drawings, circuit diagrams, sewing patterns, and less tangible artefacts such as business process models.
== Designing ==
People who produce designs are called designers. The term 'designer' usually refers to someone who works professionally in one of the various design areas. Within the professions, the word 'designer' is generally qualified by the area of practice (for example: a fashion designer, a product designer, a web designer, or an interior designer), but it can also designate other practitioners such as architects and engineers (see below: Types of designing). A designer's sequence of activities to produce a design is called a design process, with some employing designated processes such as design thinking and design methods. The process of creating a design can be brief (a quick sketch) or lengthy and complicated, involving considerable research, negotiation, reflection, modeling, interactive adjustment, and re-design.
Designing is also a widespread activity outside of the professions of those formally recognized as designers. In his influential book The Sciences of the Artificial, the interdisciplinary scientist Herbert A. Simon proposed that, "Everyone designs who devises courses of action aimed at changing existing situations into preferred ones." According to the design researcher Nigel Cross, "Everyone can – and does – design," and "Design ability is something that everyone has, to some extent, because it is embedded in our brains as a natural cognitive function."
== History of design ==
The study of design history is complicated by varying interpretations of what constitutes 'designing'. Many design historians, such as John Heskett, look to the Industrial Revolution and the development of mass production. Others subscribe to conceptions of design that include pre-industrial objects and artefacts, beginning their narratives of design in prehistoric times. Originally situated within art history, the historical development of the discipline of design history coalesced in the 1970s, as interested academics worked to recognize design as a separate and legitimate target for historical research. Early influential design historians include German-British art historian Nikolaus Pevsner and Swiss historian and architecture critic Sigfried Giedion.
== Design education ==
In Western Europe, institutions for design education date back to the nineteenth century. The Norwegian National Academy of Craft and Art Industry was founded in 1818, followed by the United Kingdom's Government School of Design (1837), and Konstfack in Sweden (1844). The Rhode Island School of Design was founded in the United States in 1877. The German art and design school Bauhaus, founded in 1919, greatly influenced modern design education.
Design education covers the teaching of theory, knowledge, and values in the design of products, services, and environments, with a focus on the development of both particular and general skills for designing. Traditionally, its primary orientation has been to prepare students for professional design practice, based on project work and studio, or atelier, teaching methods.
There are also broader forms of higher education in design studies and design thinking. Design is also a part of general education, for example within the curriculum topic, Design and Technology. The development of design in general education in the 1970s created a need to identify fundamental aspects of 'designerly' ways of knowing, thinking, and acting, which resulted in establishing design as a distinct discipline of study.
== Design process ==
Substantial disagreement exists concerning how designers in many fields, whether amateur or professional, alone or in teams, produce designs. Design researchers Dorst and Dijkhuis acknowledged that "there are many ways of describing design processes," and compare and contrast two dominant but different views of the design process: as a rational problem-solving process and as a process of reflection-in-action. They suggested that these two paradigms "represent two fundamentally different ways of looking at the world – positivism and constructionism." The paradigms may reflect differing views of how designing should be done and how it actually is done, and both have a variety of names. The problem-solving view has been called "the rational model," "technical rationality" and "the reason-centric perspective." The alternative view has been called "reflection-in-action," "coevolution" and "the action-centric perspective."
=== Rational model ===
The rational model was independently developed by Herbert A. Simon, an American scientist, and two German engineering design theorists, Gerhard Pahl and Wolfgang Beitz. It posits that:
Designers attempt to optimize a design candidate for known constraints and objectives.
The design process is plan-driven.
The design process is understood in terms of a discrete sequence of stages.
The rational model is based on a rationalist philosophy and underlies the waterfall model, systems development life cycle, and much of the engineering design literature. According to the rationalist philosophy, design is informed by research and knowledge in a predictable and controlled manner.
Typical stages consistent with the rational model include the following:
Pre-production design
Design brief – initial statement of intended outcome.
Analysis – analysis of design goals.
Research – investigating similar designs in the field or related topics.
Specification – specifying requirements of a design for a product (product design specification) or service.
Problem solving – conceptualizing and documenting designs.
Presentation – presenting designs.
Design during production.
Development – continuation and improvement of a design.
Product testing – in situ testing of a design.
Post-production design feedback for future designs.
Implementation – introducing the design into the environment.
Evaluation and conclusion – summary of process and results, including constructive criticism and suggestions for future improvements.
Redesign – any or all stages in the design process repeated (with corrections made) at any time before, during, or after production.
Each stage has many associated best practices.
==== Criticism of the rational model ====
The rational model has been widely criticized on two primary grounds:
Designers do not work this way – extensive empirical evidence has demonstrated that designers do not act as the rational model suggests.
Unrealistic assumptions – goals are often unknown when a design project begins, and the requirements and constraints continue to change.
=== Action-centric model ===
The action-centric perspective is a label given to a collection of interrelated concepts, which are antithetical to the rational model. It posits that:
Designers use creativity and emotion to generate design candidates.
The design process is improvised.
No universal sequence of stages is apparent – analysis, design, and implementation are contemporary and inextricably linked.
The action-centric perspective is based on an empiricist philosophy and broadly consistent with the agile approach and methodical development. Substantial empirical evidence supports the veracity of this perspective in describing the actions of real designers. Like the rational model, the action-centric model sees design as informed by research and knowledge.
At least two views of design activity are consistent with the action-centric perspective. Both involve these three basic activities:
In the reflection-in-action paradigm, designers alternate between "framing", "making moves", and "evaluating moves". "Framing" refers to conceptualizing the problem, i.e., defining goals and objectives. A "move" is a tentative design decision. The evaluation process may lead to further moves in the design.
In the sensemaking–coevolution–implementation framework, designers alternate between its three titular activities. Sensemaking includes both framing and evaluating moves. Implementation is the process of constructing the design object. Coevolution is "the process where the design agent simultaneously refines its mental picture of the design object based on its mental picture of the context, and vice versa".
The concept of the design cycle is understood as a circular time structure, which may start with the thinking of an idea, then expressing it by the use of visual or verbal means of communication (design tools), the sharing and perceiving of the expressed idea, and finally starting a new cycle with the critical rethinking of the perceived idea. Anderson points out that this concept emphasizes the importance of the means of expression, which at the same time are means of perception of any design ideas.
== Philosophies ==
Philosophy of design is the study of definitions, assumptions, foundations, and implications of design. There are also many informal 'philosophies' for guiding design such as personal values or preferred approaches.
=== Approaches to design ===
Some of these values and approaches include:
Critical design uses designed artefacts as an embodied critique or commentary on existing values, morals, and practices in a culture. Critical design can make aspects of the future physically present to provoke a reaction.
Ecological design is a design approach that prioritizes the consideration of the environmental impacts of a product or service, over its whole lifecycle. Ecodesign research focuses primarily on barriers to implementation, ecodesign tools and methods, and the intersection of ecodesign with other research disciplines.
Participatory design (originally co-operative design, now often co-design) is the practice of collective creativity to design, attempting to actively involve all stakeholders (e.g. employees, partners, customers, citizens, end-users) in the design process to help ensure the result meets their needs and is usable. Recent research suggests that designers create more innovative concepts and ideas when working within a co-design environment with others than they do when creating ideas on their own.
Scientific design refers to industrialised design based on scientific knowledge. Science can be used to study the effects and need for a potential or existing product in general and to design products that are based on scientific knowledge. For instance, a scientific design of face masks for COVID-19 mitigation may be based on investigations of filtration performance, mitigation performance, thermal comfort, biodegradability and flow resistance.
Service design is a term that is used for designing or organizing the experience around a product and the service associated with a product's use. The purpose of service design methodologies is to establish the most effective practices for designing services, according to both the needs of users and the competencies and capabilities of service providers.
Sociotechnical system design, a philosophy and tools for participative designing of work arrangements and supporting processes – for organizational purpose, quality, safety, economics, and customer requirements in core work processes, the quality of peoples experience at work, and the needs of society.
Transgenerational design, the practice of making products and environments compatible with those physical and sensory impairments associated with human aging and which limit major activities of daily living.
User-centered design, which focuses on the needs, wants, and limitations of the end-user of the designed artefact. One aspect of user-centered design is ergonomics.
== Relationship with the arts ==
The boundaries between art and design are blurry, largely due to a range of applications both for the term 'art' and the term 'design'. Applied arts can include industrial design, graphic design, fashion design, and the decorative arts which traditionally includes craft objects. In graphic arts (2D image making that ranges from photography to illustration), the distinction is often made between fine art and commercial art, based on the context within which the work is produced and how it is traded.
== Types of designing ==
== See also ==
== References ==
== Further reading ==
Margolin, Victor. World History of Design. New York: Bloomsbury Academic, 2015. (2 vols) ISBN 9781472569288.
Raizman, David Seth (12 November 2003). The History of Modern Design. Pearson. ISBN 978-0131830400. | Wikipedia/Designing |
While sensemaking has been studied by other disciplines under other names for centuries, in information science and computer science the term "sensemaking" has primarily marked two distinct but related topics. Sensemaking was introduced as a methodology by Brenda Dervin in the 1980s and to human–computer interaction by PARC researchers Daniel M. Russell, Mark Stefik, Peter Pirolli, and Stuart Card in 1993.
In information science, the term is often written as "sense-making". In both cases, the concept has been used to bring together insights drawn from philosophy, sociology, and cognitive science (especially social psychology). Sensemaking research is therefore often presented as an interdisciplinary research programme.
== As a process ==
Given a body of data, sensemaking can be described as the process of developing a representation and encoding data in that representation to answer questions specific to a task, such as decision-making and problem-solving (Russell et al., 1993). Gary A. Klein and colleagues (Klein et al. 2006b) conceptualize sensemaking as a set of processes that is initiated when an individual or organization recognizes the inadequacy of their current understanding of events.
Sensemaking is an active two-way process of fitting data into a frame (mental model) and fitting a frame around the data. Neither data nor frame comes first; data evoke frames and frames select and connect data. When there is no adequate fit, the data may be reconsidered or an existing frame may be revised. This description resembles the recognition-metacognition model (Cohen et al., 1996), which describes the metacognitive processes that are used by individuals to build, verify, and modify working models (or "stories") in situational awareness to account for an unrecognised situation. Such notions also echo the processes of assimilation and accommodation in Jean Piaget's theory of cognitive development (e.g., Piaget, 1972, 1977).
== As methodology ==
Brenda Dervin (Dervin, 1983, 1992, 1996) has investigated individual sensemaking, developing theories about the "cognitive gap" that individuals experience when attempting to make sense of observed data. Because much of this applied psychological research is grounded within the context of systems engineering and human factors, it aims to answer the need for concepts and performance to be measurable and for theories to be testable. Accordingly, sensemaking and situational awareness are viewed as working concepts that enable researchers to investigate and improve the interaction between people and information technology. This perspective emphasizes that humans play a significant role in adapting and responding to unexpected or unknown situations, as well as recognized situations. Dervin's work has largely focused on developing philosophical guidance for method, including methods of substantive theorizing and conducting research (Naumer, C. et al., 2008).
== In human–computer interaction ==
After a seminal paper on sensemaking in the human–computer interaction (HCI) field was published in 1993 (Russell et al., 1993), there was a great deal of activity around the understanding of how to design interactive systems for sensemaking, and workshops on sensemaking were held at prominent HCI conferences (e.g., Russell et al., 2009).
== See also ==
Augmented cognition
== References (information science) == | Wikipedia/Sensemaking_(information_science) |
Constructionist learning is a theory of learning centred on mental models. Constructionism advocates student-centered, discovery learning where students use what they already know to acquire more knowledge. Students learn through participation in project-based learning where they make connections between different ideas and areas of knowledge facilitated by the teacher through coaching rather than using lectures or step-by-step guidance. Further, constructionism holds that learning can happen most effectively when people are active in making tangible objects in the real world. In this sense, constructionism is connected with experiential learning and builds on Jean Piaget's epistemological theory of constructivism.
Seymour Papert defined constructionism in a proposal to the National Science Foundation titled Constructionism: A New Opportunity for Elementary Science Education as follows:
The word constructionism is a mnemonic for two aspects of the theory of science education underlying this project. From constructivist theories of psychology we take a view of learning as a reconstruction rather than as a transmission of knowledge. Then we extend the idea of manipulative materials to the idea that learning is most effective when part of an activity the learner experiences as constructing a meaningful product.
Some scholars have tried to describe constructionism as a "learning-by-making" formula but, as Seymour Papert and Idit Harel say at the start of Situating Constructionism, it should be considered "much richer and more multifaceted, and very much deeper in its implications than could be conveyed by any such formula."
Papert's ideas became well known through the publication of his seminal book Mindstorms: Children, Computers, and Powerful Ideas (Basic Books, 1980). Papert described children creating programs in the Logo educational programming language. He likened their learning to living in a "mathland" where learning mathematical ideas is as natural as learning French while living in France.
== Instructional principles ==
Constructionist learning involves students drawing their own conclusions through creative experimentation and the making of social objects. The constructionist teacher takes on a mediational role rather than adopting an instructional role. Teaching "at" students is replaced by assisting them to understand—and help one another to understand—problems in a hands-on way. The teacher's role is not to be a lecturer but a facilitator who coaches students to attaining their own goals.
=== Problem-based learning ===
Problem-based learning is a constructionist method which allows students to learn about a subject by exposing them to multiple problems and asking them to construct their understanding of the subject through these problems. This kind of learning can be very effective in mathematics classes because students try to solve the problems in many different ways, stimulating their minds.
The following five strategies make problem-based learning more effective:
The learning activities should be related to a larger task. The larger task is important because it allows students to see that the activities can be applied to many aspects of life and, as a result, students are more likely to find the activities they are doing useful.
The learner needs to be supported to feel that they are beginning to have ownership of the overall problem.
An authentic task should be designed for the learner. This means that the task and the learner's cognitive ability have to match the problems to make learning valuable.
Reflection on the content being learned should occur so that learners can think through the process of what they have learned.
Allow and encourage the learners to test ideas against different views in different contexts.
=== Constructionism in social sciences ===
Not only can constructionism be applied to mathematics but to the social sciences as well. For example, instead of having students memorize geography facts, a teacher could give students blank maps that show unlabeled rivers, lakes, and mountains, and then ask the students to decipher where major cities might be located without the help of books or maps. This would require students to locate these areas without using prepared resources, but their prior knowledge and reasoning ability instead.
Digital storytelling is another application of constructionism to the social sciences. Students can visit institutions in the local community, to understand and document their histories, develop local maps using tools like OpenStreetMap to enrich digital maps and debate the purpose and activities of local public institutions to build an understanding of political science (civics). Digital storytelling has been used by government schools in Bengaluru to develop students understanding in the social sciences.
== Constructionism and technology ==
Papert was a huge proponent of bringing technology to classrooms, beginning with his early uses of the Logo language to teach mathematics to children. While constructionism has, due to its impetus, been primarily used in science and mathematics teaching (in the form of inquiry-based science), it is arguable that it developed in a different form in the field of media studies in which students often engage with media theory and practice simultaneously in a complementary praxis. More recently it has gained a foothold in applied linguistics in the field of second language acquisition (SLA). One such application has been the use of the popular game SimCity as a means of teaching English using constructionist techniques.
Beginning in the 1980s, The LEGO Group funded research of Papert's research group at the MIT Media Laboratory, which at the time was known as the "Epistemology and Learning Group." When LEGO launched its LEGO Mindstorms Robotics Invention System in 1998, which was based on the work of his group, it received permission to use the moniker "Mindstorms" from Seymour's 1980 book title. In The LEGO Group's LEGO Serious Play project, business people learn to express corporate issues and identity through the medium of plastic bricks.
From 2005 to 2014, there was the One Laptop Per Child initiative to put constructionist learning into practice in the developing world. The aim was to provide $100 laptops to every child in the developing world.
== Computer programming languages ==
A number of programming languages have been created, wholly or in part, for educational use, to support the constructionist approach to learning. These languages are dynamically typed, and are reflective. They include:
Logo is a multi-paradigm language, which is an easier-to-read adaptation and dialect of Lisp, without the parentheses. Logo is known for its introduction of turtle graphics to elementary schoolchildren in the 1980s. Its creators were Wally Feurzeig, Cynthia Solomon, and Papert.
Smalltalk is an object-oriented language that was designed and created at Xerox PARC by a team led by Alan Kay.
AgentSheets is an early block-based programming environment for kids to create games and simulations. It is developed by Alexander Repenning
Etoys is being developed since the 1990s under the direction of Alan Kay, most recently by the Viewpoints Research Institute, based on Morphic tile scripting. Etoys was initially targeted at primary school math and science education.
Physical Etoys is an extension of Etoys that allows to control different devices such as Lego NXT, Arduino Board, Sphero, Kinect, Duinobot, Wiimote among others.
Scratch was developed in the early 21st century at MIT Media Lab Lifelong Kindergarten Group led by Papert's pupil Mitchel Resnick. Like Etoys, it is based on Morphic tile scripts. Scratch was initially designed specifically to enhance the development of technological fluency at after-school centers in economically disadvantaged communities.
StarLogo TNG was developed by the MIT Scheller Teacher Education Program under Eric Klopfer. It combines a block programming interface with 3D graphics. It is targeted at programming games and game-like simulations in middle and secondary schools.
NetLogo was developed by Uri Wilensky. It was developed to teach children computational reasoning and thinking, and extends the Logo language by enabling the existence of many, many turtles at the same time. NetLogo is widely used not only in the K–12 environment, but also by researchers interested in the concept of agent-based modeling
AgentCubes is a block-based programming environment for kids to create 3D games and simulation. It is developed by Alexander Repenning
Easy Java Simulations or Ejs or EJS was developed by Open Source Physics under Francisco Esquembre. The user is working at a higher conceptual level, declaring and organizing the equations and other mathematical expressions that operate the simulation. It is targeted at programming physics simulations in secondary schools and universities.
LEGO WeDo is a graphical programming language for children of age 7 years and up, used with the LEGO WeDo power function hub.
LEGO MINDSTORMS EV3 is a dataflow graphical programming language for children age 10+.
Robot Emil is a constructionist educational tool for children. It is targeted at primary schools and teaches programming step by step.
== References ==
== External links ==
The Nature of Constructionist learning – MIT open-to-all online reading list on constructionism
Lifelong Kindergarten Group – MIT Lifelong Kindergarten research group
Center for Connected Learning and Computer-Based Modeling – Northwestern University's Constructionist learning and agent-based modeling research group
Ackerman on Constructivism vs Constructionism – Edith Ackermann draws out the differences between Piaget's Constructivism, Vygotsky's Socio-Constructivism and Papert's ConstructioNism | Wikipedia/Constructionism_(learning_theory) |
Design and Technology (D&T) is a school subject taught in the United Kingdom to pupils in primary and secondary schools. It first appeared as a titled subject in the first National Curriculum for England in 1990. It has undergone several reviews when the whole National Curriculum has been reviewed, the most recent in 2013.
D&T is also taught in many countries around the world such as India, United States, Australia, New Zealand, Ireland, Malta, China, South Africa, Latvia, France, Finland and Singapore.
As a school subject it involves students in designing in a practical context using a range or materials and media. It is also a university course in many countries, including Australia, Canada, the US, Singapore, South Africa, Netherlands and New Zealand, both for the preparation of teachers and for general education in areas such as industrial design. Some of the UK universities which deliver courses include: Brighton, Sheffield Hallam, Goldsmiths, University of London and Greenwich.
== Design and Technology in England ==
=== Purpose and aims of D&T ===
The National Curriculum for England states that the purpose of D&T is:
"Design and Technology is an inspiring, rigorous and practical subject. Using creativity and imagination, pupils design and make products that solve real and relevant problems within a variety of contexts, considering their own and others’ needs, wants and values. They acquire a broad range of subject knowledge and draw on disciplines such as mathematics, physics, mechanics, electronics, engineering, computing and art. Pupils learn how to take risks, becoming resourceful, innovative, enterprising and capable citizens. Through the evaluation of past and present design and technology, they develop a critical understanding of its impact on daily life and the wider world. High-quality design and technology education makes an essential contribution to the creativity, culture, wealth and well-being of the nation."
And there are four aims:
"to ensure that all pupils:
develop the creative, technical and practical expertise needed to perform everyday tasks confidently and to participate successfully in an increasingly technological world
build and apply a repertoire of knowledge, understanding and skills in order to design and make high-quality prototypes and products for a wide range of users
critique, evaluate and test their ideas and products and the work of others
understand and apply the principles of nutrition and learn how to cook"
The second goal is known as "design and technology capability" and is the interaction of responding to a design and technology context whilst drawing on the resources of knowledge and experience, where pupils develop “the power to produce change and improvement in the made world”.
=== Design and Technology qualifications ===
==== GCSE D&T (2017 onwards) ====
Taught primarily to pupils in upper secondary school (years 10-11, aged 14-16) the GCSE incorporates all material areas (with the exception of food which is now a separate GCSE). Similar to the previous GCSE, the new GCSE Specifications have two assessed components - an exam and a non-examined assessment (NEA) but with a 50:50 split of the marks.
==== A level ====
A and AS level examinations prepare students for individualised learning and problem solving, which is essential in business and industry. Time management is a key factor to candidates' success within the coursework elements of the qualification. The examinations are as rigorous as any other subject. Indeed, due to the complexity and variety of tasks and organisation skills required this examination and course is very demanding. The subject covers activities from control technology to aesthetic product design. Students have to use all types of computer software including computer-aided design and manufacture, spreadsheets and computer presentations. Outputs from such work are often sent to CNC machines for manufacture.
==== Previous qualification in D&T ====
With the first National Curriculum new GCSE qualifications were introduced for D&T in England, Wales and Northern Ireland. Unlike the National Curriculum the previous subject titles were retained (e.g. craft, design and technology (CDT) and home economics) and others added (e.g. electronics, food technology, textiles technology and systems and control). These GCSE specifications had two assessed components:
50% of the final mark for coursework
50% for an examination of general subject knowledge (materials, processes, techniques and sustainability etc.).
GCSE D&T titles that were offered included:
GCSE Design and Technology: Electronic Products
GCSE Design and Technology: Food Technology
GCSE Design and Technology: Graphic Products
GCSE Design and Technology: Resistant Materials
GCSE Design and Technology: Systems and Control
GCSE Design and Technology: Textiles Technology
GCSE Design and Technology: Product Design
== International Baccalaureate in Design Technology ==
The IB Design Technology (DT) is an elective subject offered in many International Baccalaureate schools globally. Design is also offered in the IB Middle Years Programme (MYP) as a compulsory subject for grades 6–10, and at the Diploma Programme level (from grades 11-12). IB Design Technology is very similar in content to Design and Technology. It is one of the Group 4 sciences.
The primary focus of MYP Design is to give students an understanding of the design cycle, through a practical programme. The student will complete projects based on solving a real and authentic problem. Students document their progress as they follow the design cycle to come to a feasible solution. They create the solution and then evaluate it following thorough testing.
The Diploma Programme of Design Technology is a two-year introduction to designing, a range of fundamentals of technology, and global technological issues. It provides students with the knowledge to be able to design and make in school workshops, and also to develop an informed literacy about technology in general. Because it is an international curriculum it has a particular focus on global environmental issues. It covers core topics in human factors and ergonomics, resource management and sustainable production, modeling, raw materials to final production, innovation and design, classic design. It covers advanced higher level topics in user centered design, sustainability, innovation and markets, and commercial production. The diploma is accepted for university entrance in many countries, and is a good preparation for careers in areas such as engineering, architecture, product design, interior design, design and education.
== Scotland ==
Technological education is part of the Scottish secondary school curriculum. Technological education is segregated into various subjects available at National 4, National 5, Higher and Advanced Higher
Standard Subject in Technical
Graphic Communication
Design and Manufacture
Engineering Science
Practical Electronics (available to N5 level)
Practical Woodwork (available to N5 level)
Practical Metalwork (available to N5 level)
Specialist Subjects within Technical
Architectural technology
Automotive engineering
Civil engineering
Building services
Construction
Electrical engineering
Mechanical engineering
Mechatronics
== Wales ==
In 2022, the new Welsh Curriculum combined distinct school subjects into Areas of Learning Experience (AoLE). What was D&T now comes under the "Science and Technology" AoLE, though not all schools have fully transitioned to this new style of teaching as of 2025 and still practice D&T as a standalone subject.
== Awards ==
In the UK, the Arkwright Scholarships Trust awards two-year scholarships to students who are taking GCSE/Scottish Standard Grade in design & technology. The Arkwright Engineering Scholarships support students through their A levels/Scottish Highers and encourage them to study engineering or a related area of design at a top university or through a high-quality industrial apprenticeship.
== See also ==
Industrial arts, the equivalent course in the United States and Australia (Victoria).
== References == | Wikipedia/Design_and_Technology |
Design is the creation of a plan or specification for the construction of an object or a system.
Design or The Design may also refer to:
== Science and mathematics ==
Block design
Combinatorial design
Design of experiments
Engineering design process
Randomized block design, in statistics
== Entertainment ==
Design (band), a 1970s British vocal group
Design, a record label founded by Marco Carola
The Design (album)
The Design (professional wrestling)
== Other uses ==
Communication design
Fashion design
Game design
Graphic design
Interior design
Scenic design
== See also ==
Designer (disambiguation)
By Design (disambiguation)
Interior Design (disambiguation)
Design methods | Wikipedia/Design_(disambiguation) |
Vexillography ( VEK-sih-LOG-rə-fee) is the art and practice of designing flags; a person who designs flags is a vexillographer. Vexillography is allied with vexillology, the scholarly study of flags, but is not synonymous with that discipline.
== Background of flag design ==
Flag designs exhibit a number of regularities, arising from a variety of practical concerns, historical circumstances, and cultural prescriptions that have shaped and continue to shape their evolution.
Vexillographers face the necessity for the design to be manufactured (and often mass-produced) into or onto a piece of cloth, which will subsequently be hoisted aloft in the outdoors to represent an organization, individual, idea, or group. In this respect, flag design departs considerably from logo design: logos are predominantly still images suitable for reading off a page, screen, or billboard; while flags are alternately draped and fluttering images - visible from a variety of distances and angles (including the reverse). The prevalence of simple bold colors and shapes in flag design attests to these practical issues.
Flag design has a history, and new designs often refer back to previous designs, effectively quoting, elaborating, or commenting upon them. Families of current flags may derive from a few common ancestors - as in the cases of the Pan-African colours, the Pan-Arab colors, the Pan-Slavic colors, the Nordic Cross flag and the Ottoman flag.
Certain cultures prescribe the proper design of their own flags, through heraldic or other authoritative systems. Prescription may be based on religious principles: see, for example, Islamic flags. Vexillographers have begun to articulate design principles, such as those jointly published by the North American Vexillological Association and the Flag Institute in their Guiding Principles of Flag Design.
== Principles of design ==
In 2006, the North American Vexillological Association published a booklet titled "Good" Flag, "Bad" Flag to aid those wishing to design or re-design a flag. Taking a minimalist approach, the booklet lists five basic flag design principles which have become a standard reference in the vexillographer community. In 2014, the North American Vexillological Association, alongside the Flag Institute created an updated booklet titled The Commission's Report on the Guiding Principles of Flag Design, which addresses issues present in "Good" Flag, "Bad" Flag, and goes more in-depth on the ideas laid forth in the aforementioned booklet. The guidelines in this booklet can be summarized as follows:
=== Basics ===
Keep in mind the physics of a flag in flight when designing a flag
Simple designs are more easily remembered while complex ones are harder to recall and recreate
Flags should have distinctive designs that separate them from others
Designs and trends should be avoided if there is a possibility that they can date quickly
=== Color ===
Using fewer colors keeps designs simple and bold (2-3 colors are strongly recommended)
Contrast is important; use light on dark and dark on light
Modern printing techniques have made more shades of color available than previously, and this can be used advantageously
Designs should make the edge of a flag be well-defined so as to not get visually lost in the background of where it is flying
Gradient on flags (Like the Flag of Guatemala ) make it look too computer generated, and make it difficult to sew/draw. Try to avoid gradients
=== Structure ===
Charges are best placed in the canton, hoist, or center of a design as these are the most visually prominent areas
Flag designs are usually longer than they are tall
Having different designs on the obverse and reverse of a flag undermines recognition and increases cost of production
=== Devices ===
A single device should be used in a prominent position to ensure that people can recognize the flag whether it is in flight or at rest
When multiple devices are included, different background colors can be used to "anchor" the devices into the overall design
Devices should be stylized graphical representations as opposed to realistic drawings, so the flag can easily be recreated and recognized by anyone
Avoid text on flags; it is difficult to read while the flag is in flight and will appear backwards on the flag's reverse
Charges with directionality traditionally face towards the hoist, or flagpole
Seals, coats of arms, or logos are usually too complex to be used effectively on a flag, although exceptions exist
=== Symbolism ===
Symbols should be both distinct and representative
A flag should represent the totality of any given community as opposed to its individual parts
A flag should emphasize its own identity over higher-level groupings, otherwise distinctiveness is lost
Symbolism relating to other entities should only be used if there is a clear, direct relevance
Designers should avoid representing any particular reference in multiple ways, and instead try to make a single definitive reference
== Prominent vexillographers ==
Columbano Bordalo Pinheiro, designer of the flag of Portugal
Luis and Sabino Arana, designers of the Ikurriña (the flag of the Basque Country)
Graham Bartram, designer of the flag of Tristan da Cunha and others
Manuel Belgrano, designer of the flag of Argentina
Frederick 'Fred' Brownell, designer of the flags of South Africa and Namibia
Ron Cobb, designer of the American Ecology Flag
John Eisenmann, designer of the flag of the U.S. state of Ohio
Mohamed Hamzah, designer of the flag of Malaya
Quamrul Hassan, designer of the flag of Bangladesh
Cederic Herbert, designer of the flag of the short-lived Zimbabwe Rhodesia
Francis Hopkinson, generally acknowledged designer of the American flag
Friedensreich Hundertwasser, designer of a koru flag, among others
Susan K. Huhume, designer of the flag of Papua New Guinea
Sharif Hussein, designer of the flag of the Arab Revolt
James I of England, designer of the first flag of Great Britain
Syed Amir-uddin Kedwaii, designer of the flag of Pakistan
Lu Haodong, designer of the Blue Sky with a White Sun flag of the Republic of China
Nicola Marschall, designer of the "Stars and Bars", the First National Flag of the Confederate States of America
John McConnell, designer of a flag of the Earth
Fredrik Meltzer, designer of the flag of Norway
Raimundo Teixeira Mendes, designer of the flag of Brazil
William Porcher Miles, designer of the battle flag of the Confederate States of America
Francisco de Miranda, designer of the flag of Venezuela, upon which the present flags of Colombia and Ecuador are based.
Theodosia Okoh, designer of the flag of Ghana
Christopher Pratt, designer of the flag of the Canadian province of Newfoundland and Labrador
Orren Randolph Smith, citizen of North Carolina who is co-credited as being the father of the "Stars and Bars" flag, along with Nicola Marschall.
Whitney Smith, designer of the flag of Guyana and other flags
George Stanley, designer of the flag of Canada
Joaquín Suárez, designer of the flag of Uruguay
Pingali Venkayya, designer of the flag of India
Robert Watt, designer of the flag of Vancouver, British Columbia, Canada
Oliver Wolcott Jr., designer of the flag of the United States Customs Service
Zeng Liansong, designer of the flag of the People's Republic of China
İsmet Güney, designer of the flag of Cyprus
Nguyen Huu Tien, designer of the flag of Vietnam
Gilbert Baker, designer of the rainbow flag symbol of the LGBT Movement
Alexander Baretich, designer of the Cascadian bioregional flag AKA Doug flag
Ralph Eugene Diffendorfer, co-designer of the Christian Flag
Christopher Gadsden, designer of the Gadsden flag
Monica Helms, designer of the Transgender flag
Adolf Hitler, designer of the flag of Nazi Germany, the Reichskriegsflagge and his personal standard
Betsy Ross, designer, according to legend, of the American flag during the American Revolution
Theodore Sizer, designed of the flag of St. Louis
Gerard Slevin, former Chief Herald of Ireland reputed to have helped design the flag of Europe.
Emilio Aguinaldo, 1st president of the Republic of the Philippines, along with the designer of the countries' flag.
== Notes == | Wikipedia/Vexillography |
A category of fine art, graphic art covers a broad range of visual artistic expression, typically two-dimensional graphics, i.e. produced on a flat surface, today normally paper or a screen on various electronic devices. The term usually refers to the arts that rely more on line, color or tone, especially drawing and the various forms of engraving; it is sometimes understood to refer specifically to drawing and the various printmaking processes, such as line engraving, aquatint, drypoint, etching, mezzotint, monotype, lithography, and screen printing (silk-screen, serigraphy). Graphic art mostly includes calligraphy, photography, painting, typography, computer graphics, and bindery. It also encompasses drawn plans and layouts for interior and architectural designs.
In museum parlance "works on paper" is a common term, covering the various types of traditional fine art graphic art. There is now a large sector of graphic designers working mostly on web design.
== History ==
Throughout history, technological inventions have shaped the development of graphic art. In 2500 BC, the Egyptians used graphic symbols to communicate their thoughts in a written form known as hieroglyphics. The Egyptians wrote and illustrated narratives on rolls of papyrus to share the stories and art with others.
During the Middle Ages, scribes manually copied each individual page of manuscripts to maintain their sacred teachings. The scribes would leave marked sections of the page available for artists to insert drawings and decorations. Using art alongside the carefully lettered text enhanced the religious reading experience.
In 1450, Johannes Gutenberg created the first upgraded moving type of mechanical equipment called as the printing press. His printing press aided the mass creation of text and visual art, eventually obviating the need for hand transcriptions.
Again during the Renaissance years, graphic art in the form of printing played a major role in the spread of classical learning in Europe. Within these manuscripts, book designers focused heavily on the typeface.
Due to the development of larger fonts during the Industrial Revolution, posters became a popular form of graphic art used to communicate the latest information as well as to advertise the latest products and services.
The invention and popularity of film and television changed graphic art through the additional aspect of motion as advertising agencies attempted to use kinetics to their advantage.
The next major change in graphic arts came when the personal computer was invented in the twentieth century. Powerful computer software enables artists to manipulate images in a much faster and simpler way than the skills of board artists prior to the 1990s. With quick calculations, computers easily recolor, scale, rotate, and rearrange images if the programs are known.
The design of street signs has been impacted by scientific examinations into readability. New York City is in the midst of replacing all of its street signs that have all capital characters with ones that only have upper and lower case letters. They anticipate that greater readability will improve wayfinding and greatly reduce collisions and injuries.
== See also ==
Animation
Communication design
Crowdsourcing creative work
Digital art
Illustration
Caricature
Cartoon
Comics
Graphic design
Painting
Performance art
Printmaking
== References == | Wikipedia/Graphic_art |
A design is the concept or proposal for an object, process, or system. The word design refers to something that is or has been intentionally created by a thinking agent, and is sometimes used to refer to the inherent nature of something – its design. The verb to design expresses the process of developing a design. In some cases, the direct construction of an object without an explicit prior plan may also be considered to be a design (such as in arts and crafts). A design is expected to have a purpose within a specific context, typically aiming to satisfy certain goals and constraints while taking into account aesthetic, functional and experiential considerations. Traditional examples of designs are architectural and engineering drawings, circuit diagrams, sewing patterns, and less tangible artefacts such as business process models.
== Designing ==
People who produce designs are called designers. The term 'designer' usually refers to someone who works professionally in one of the various design areas. Within the professions, the word 'designer' is generally qualified by the area of practice (for example: a fashion designer, a product designer, a web designer, or an interior designer), but it can also designate other practitioners such as architects and engineers (see below: Types of designing). A designer's sequence of activities to produce a design is called a design process, with some employing designated processes such as design thinking and design methods. The process of creating a design can be brief (a quick sketch) or lengthy and complicated, involving considerable research, negotiation, reflection, modeling, interactive adjustment, and re-design.
Designing is also a widespread activity outside of the professions of those formally recognized as designers. In his influential book The Sciences of the Artificial, the interdisciplinary scientist Herbert A. Simon proposed that, "Everyone designs who devises courses of action aimed at changing existing situations into preferred ones." According to the design researcher Nigel Cross, "Everyone can – and does – design," and "Design ability is something that everyone has, to some extent, because it is embedded in our brains as a natural cognitive function."
== History of design ==
The study of design history is complicated by varying interpretations of what constitutes 'designing'. Many design historians, such as John Heskett, look to the Industrial Revolution and the development of mass production. Others subscribe to conceptions of design that include pre-industrial objects and artefacts, beginning their narratives of design in prehistoric times. Originally situated within art history, the historical development of the discipline of design history coalesced in the 1970s, as interested academics worked to recognize design as a separate and legitimate target for historical research. Early influential design historians include German-British art historian Nikolaus Pevsner and Swiss historian and architecture critic Sigfried Giedion.
== Design education ==
In Western Europe, institutions for design education date back to the nineteenth century. The Norwegian National Academy of Craft and Art Industry was founded in 1818, followed by the United Kingdom's Government School of Design (1837), and Konstfack in Sweden (1844). The Rhode Island School of Design was founded in the United States in 1877. The German art and design school Bauhaus, founded in 1919, greatly influenced modern design education.
Design education covers the teaching of theory, knowledge, and values in the design of products, services, and environments, with a focus on the development of both particular and general skills for designing. Traditionally, its primary orientation has been to prepare students for professional design practice, based on project work and studio, or atelier, teaching methods.
There are also broader forms of higher education in design studies and design thinking. Design is also a part of general education, for example within the curriculum topic, Design and Technology. The development of design in general education in the 1970s created a need to identify fundamental aspects of 'designerly' ways of knowing, thinking, and acting, which resulted in establishing design as a distinct discipline of study.
== Design process ==
Substantial disagreement exists concerning how designers in many fields, whether amateur or professional, alone or in teams, produce designs. Design researchers Dorst and Dijkhuis acknowledged that "there are many ways of describing design processes," and compare and contrast two dominant but different views of the design process: as a rational problem-solving process and as a process of reflection-in-action. They suggested that these two paradigms "represent two fundamentally different ways of looking at the world – positivism and constructionism." The paradigms may reflect differing views of how designing should be done and how it actually is done, and both have a variety of names. The problem-solving view has been called "the rational model," "technical rationality" and "the reason-centric perspective." The alternative view has been called "reflection-in-action," "coevolution" and "the action-centric perspective."
=== Rational model ===
The rational model was independently developed by Herbert A. Simon, an American scientist, and two German engineering design theorists, Gerhard Pahl and Wolfgang Beitz. It posits that:
Designers attempt to optimize a design candidate for known constraints and objectives.
The design process is plan-driven.
The design process is understood in terms of a discrete sequence of stages.
The rational model is based on a rationalist philosophy and underlies the waterfall model, systems development life cycle, and much of the engineering design literature. According to the rationalist philosophy, design is informed by research and knowledge in a predictable and controlled manner.
Typical stages consistent with the rational model include the following:
Pre-production design
Design brief – initial statement of intended outcome.
Analysis – analysis of design goals.
Research – investigating similar designs in the field or related topics.
Specification – specifying requirements of a design for a product (product design specification) or service.
Problem solving – conceptualizing and documenting designs.
Presentation – presenting designs.
Design during production.
Development – continuation and improvement of a design.
Product testing – in situ testing of a design.
Post-production design feedback for future designs.
Implementation – introducing the design into the environment.
Evaluation and conclusion – summary of process and results, including constructive criticism and suggestions for future improvements.
Redesign – any or all stages in the design process repeated (with corrections made) at any time before, during, or after production.
Each stage has many associated best practices.
==== Criticism of the rational model ====
The rational model has been widely criticized on two primary grounds:
Designers do not work this way – extensive empirical evidence has demonstrated that designers do not act as the rational model suggests.
Unrealistic assumptions – goals are often unknown when a design project begins, and the requirements and constraints continue to change.
=== Action-centric model ===
The action-centric perspective is a label given to a collection of interrelated concepts, which are antithetical to the rational model. It posits that:
Designers use creativity and emotion to generate design candidates.
The design process is improvised.
No universal sequence of stages is apparent – analysis, design, and implementation are contemporary and inextricably linked.
The action-centric perspective is based on an empiricist philosophy and broadly consistent with the agile approach and methodical development. Substantial empirical evidence supports the veracity of this perspective in describing the actions of real designers. Like the rational model, the action-centric model sees design as informed by research and knowledge.
At least two views of design activity are consistent with the action-centric perspective. Both involve these three basic activities:
In the reflection-in-action paradigm, designers alternate between "framing", "making moves", and "evaluating moves". "Framing" refers to conceptualizing the problem, i.e., defining goals and objectives. A "move" is a tentative design decision. The evaluation process may lead to further moves in the design.
In the sensemaking–coevolution–implementation framework, designers alternate between its three titular activities. Sensemaking includes both framing and evaluating moves. Implementation is the process of constructing the design object. Coevolution is "the process where the design agent simultaneously refines its mental picture of the design object based on its mental picture of the context, and vice versa".
The concept of the design cycle is understood as a circular time structure, which may start with the thinking of an idea, then expressing it by the use of visual or verbal means of communication (design tools), the sharing and perceiving of the expressed idea, and finally starting a new cycle with the critical rethinking of the perceived idea. Anderson points out that this concept emphasizes the importance of the means of expression, which at the same time are means of perception of any design ideas.
== Philosophies ==
Philosophy of design is the study of definitions, assumptions, foundations, and implications of design. There are also many informal 'philosophies' for guiding design such as personal values or preferred approaches.
=== Approaches to design ===
Some of these values and approaches include:
Critical design uses designed artefacts as an embodied critique or commentary on existing values, morals, and practices in a culture. Critical design can make aspects of the future physically present to provoke a reaction.
Ecological design is a design approach that prioritizes the consideration of the environmental impacts of a product or service, over its whole lifecycle. Ecodesign research focuses primarily on barriers to implementation, ecodesign tools and methods, and the intersection of ecodesign with other research disciplines.
Participatory design (originally co-operative design, now often co-design) is the practice of collective creativity to design, attempting to actively involve all stakeholders (e.g. employees, partners, customers, citizens, end-users) in the design process to help ensure the result meets their needs and is usable. Recent research suggests that designers create more innovative concepts and ideas when working within a co-design environment with others than they do when creating ideas on their own.
Scientific design refers to industrialised design based on scientific knowledge. Science can be used to study the effects and need for a potential or existing product in general and to design products that are based on scientific knowledge. For instance, a scientific design of face masks for COVID-19 mitigation may be based on investigations of filtration performance, mitigation performance, thermal comfort, biodegradability and flow resistance.
Service design is a term that is used for designing or organizing the experience around a product and the service associated with a product's use. The purpose of service design methodologies is to establish the most effective practices for designing services, according to both the needs of users and the competencies and capabilities of service providers.
Sociotechnical system design, a philosophy and tools for participative designing of work arrangements and supporting processes – for organizational purpose, quality, safety, economics, and customer requirements in core work processes, the quality of peoples experience at work, and the needs of society.
Transgenerational design, the practice of making products and environments compatible with those physical and sensory impairments associated with human aging and which limit major activities of daily living.
User-centered design, which focuses on the needs, wants, and limitations of the end-user of the designed artefact. One aspect of user-centered design is ergonomics.
== Relationship with the arts ==
The boundaries between art and design are blurry, largely due to a range of applications both for the term 'art' and the term 'design'. Applied arts can include industrial design, graphic design, fashion design, and the decorative arts which traditionally includes craft objects. In graphic arts (2D image making that ranges from photography to illustration), the distinction is often made between fine art and commercial art, based on the context within which the work is produced and how it is traded.
== Types of designing ==
== See also ==
== References ==
== Further reading ==
Margolin, Victor. World History of Design. New York: Bloomsbury Academic, 2015. (2 vols) ISBN 9781472569288.
Raizman, David Seth (12 November 2003). The History of Modern Design. Pearson. ISBN 978-0131830400. | Wikipedia/Designed |
The Global Design Database is a comprehensive online database developed and maintained by the World Intellectual Property Organization. It serves as a global resource for industrial designs, providing users access to a vast collection of international design records promoting transparency, efficiency, and accessibility in the design system. The database offers valuable tools and search functionalities to assist designers, researchers, intellectual property professionals, and policy-makers in exploring industrial designs worldwide, tracking design registrations, finding potential conflicts, giving access to design data for analysis, policy development, and academic research.
== History ==
The Global Design Database was officially launched in 2015. It was designed to provide a centralized platform for searching and retrieving design records from various national and international databases. In the following years the database continued to evolve and expand its functionalities to meet the growing demands of design users.
As of December 2023, it contains over 15.5 million records.
== Features and Functionality ==
The Global Design Database offers a range of features and tools to assist users in searching and exploring design information. Some key features include:
Extensive Coverage
The database provides access to a vast collection of design records from national and international design offices. It covers industrial designs registered under the Hague System for the International Registration of Industrial Designs, as well as national design offices from different countries. Users can search for designs registered in multiple jurisdictions, making it a valuable resource for global design protection.
Multilingual Search Interface
The Global Design Database supports multiple languages, allowing users to perform searches using keywords, design titles, applicants' names, and other relevant criteria in their preferred language. This multilingual capability enhances the usability and effectiveness of the database, enabling users to search for designs using local or international terminology.
Advanced Search Options
Users can utilize advanced search options to refine their queries and retrieve specific design records. The database offers various search filters, including design classification, status, applicant's name, and filing date, among others. These filters help users narrow their searches and locate relevant designs more efficiently.
Detailed Design Information
Users can access comprehensive information for each design record through the Global Design Database. Each record provides details such as the design title, applicant's name and address, registration and expiration dates, design classification, status, and associated documents. Users can review the design's legal status and download relevant documents for further analysis and reference.
== See also ==
Design infringment
Industrial design right
WIPO Lex
Global Brand Database
PATENTSCOPE
== References ==
== External links ==
https://designdb.wipo.int/designdb/en/index.jsp Archived 2024-10-01 at the Wayback Machine
https://guides.library.queensu.ca/patents/design-databases Archived 2023-09-24 at the Wayback Machine | Wikipedia/Global_Design_Database |
A decision cycle or decision loop is a sequence of steps used by an entity on a repeated basis to reach and implement decisions and to learn from the results. The "decision cycle" phrase has a history of use to broadly categorize various methods of making decisions, going upstream to the need, downstream to the outcomes, and cycling around to connect the outcomes to the needs.
A decision cycle is said to occur when an explicitly specified decision model is used to guide a decision and then the outcomes of that decision are assessed against the need for the decision. This cycle includes specification of desired results (the decision need), tracking of outcomes, and assessment of outcomes against the desired results.
== Examples of decision cycles ==
In quality control, PDCA (Plan–Do–Check–Act) is used.
In science, the scientific method (Observation–Hypothesis–Experiment–Evaluation) can also be seen as a decision cycle.
In the United States Armed Forces, a theory of an OODA loop (Observe–Orient–Decide–Act) has been advocated by Colonel John Boyd.
In the lean startup methodology, the Build-Measure-Learn loop is used to guide product development.
In management, Herbert A. Simon proposed a decision cycle of three steps (Intelligence–Design–Choice). Much later, other scholars expanded his framework to five steps (Intelligence–Design–Choice–Implementation–Learning).
In design thinking, the design process is often conceived as a decision cycle (or design cycle), such as Robert McKim's ETC (Express–Test–Cycle).
In the Getting Things Done time management method, workflow consists of a cycle of five stages (Collect–Process–Organize–Do–Review).
In the nursing process, the ADPIE (Assessment–Diagnosis–Planning–Implementation–Evaluation) process is used. Alternatively, the ASPIRE (Assessment–Systematic Nursing Diagnosis–Planning–Implementation–Recheck–Evaluation) model includes an additional stage—Recheck—in between Implementation and Evaluation.
In psychotherapy, the transtheoretical model posits five stages of intentional change (Precontemplation–Contemplation–Preparation–Action–Maintenance). These stages were initially conceived as linear, but John C. Norcross said that for many people the stages are more appropriately viewed as a cycle (Psych–Prep–Perspire–Persist–Relapse).
In USAID, the use of a program cycle, "codified in the Automated Directive Systems (ADS) 201, is USAID's operational model for planning, delivering, assessing, and adapting development programming in a given region or country to achieve more effective and sustainable results in order to advance U.S. foreign policy". Relatedly, within the agency there exists resources regarding adaptive management decision cycles.
== See also ==
== References == | Wikipedia/Design_cycle |
In theatre, a lighting designer (or LD) works with the director, choreographer, set designer, costume designer, and sound designer to create the lighting, atmosphere, and time of day for the production in response to the text while keeping in mind issues of visibility, safety, and cost. The LD also works closely with the stage manager or show control programming, if show control systems are used in that production. Outside stage lighting, the job of a lighting designer can be much more diverse, and they can be found working on rock and pop tours, corporate launches, art installations, or lighting effects at sporting events.
== During pre-production ==
The role of the lighting designer varies greatly within professional and amateur theater. For a Broadway show, a touring production and most regional and small productions the LD is usually an outside freelance specialist hired early in the production process. Smaller theater companies may have a resident lighting designer responsible for most of the company's productions or rely on a variety of freelance or even volunteer help to light their productions. At the off-Broadway or off-off-Broadway level, the LD will occasionally be responsible for much of the hands-on technical work (such as hanging instruments, programming the light board, etc.) that would be the work of the lighting crew in a larger theater.
The LD will read the script carefully and make notes on changes in place and time between scene—and will have meetings (called design or production meetings) with the director, designers, stage manager, and production manager to discuss ideas for the show and establish budget and scheduling details. The LD will also attend several later rehearsals to observe the way the actors are being directed to use the stage area ('blocking') during different scenes and will receive updates from the stage manager on any changes that occur. The LD will also ensure that they have an accurate plan of the theatre's lighting positions and a list of their equipment, as well as an accurate copy of the set design, especially the ground plan and section. The LD must consider the show's mood and the director's vision in creating a lighting design.
To help the LD communicate artistic vision, they may employ renderings, storyboards, photographs, reproductions of artwork, or mockups of effects to help communicate how the lighting should look. Various forms of paperwork are essential for the LD to successfully communicate their design to various production team members. Examples of typical paperwork include cue sheets, light plots, instrument schedules, shop orders, and focus charts. Cue sheets communicate the placement of cues that the LD has created for the show, using artistic terminology rather than technical language, and information on exactly when each cue is called so that the stage manager and the assistants know when and where to call the cue. Cue sheets are of the most value to stage management.
The light plot is a scale drawing that communicates the location of lighting fixtures and lighting positions so a team of electricians can independently install the lighting system. Next to each instrument on the plan will be information for any color gel, gobo, or other accessories that need to go with it, and its channel number. Often, paperwork listing all of this information is also generated by using a program such as Lightwright. The lighting designer uses this paperwork to aid in the visualization of not only ideas but also simple lists to assist the master electrician during load-in, focus, and technical rehearsals. Professional LDs generally use special computer-aided design packages to create accurate and easily readable drafted plots that can be swiftly updated as necessary. The LD will discuss the plot with the show's production manager and the theatre's master electrician or technical director to make sure there are no unforeseen problems during load-in.
The lighting designer is responsible, in conjunction with the production's independently hired production electrician, who will interface with the theater's master electrician, for directing the theater's electrics crew in the realization of their designs during the technical rehearsals. After the Electricians have hung, circuited, and patched the lighting units, the LD will direct the focusing (pointing, shaping and sizing of the light beams) and gelling (coloring) of each unit.
After focus has occurred the LD usually sits at a temporary desk (tech table) in the theater (typically on the center line in the middle of the house) where they have a good view of the stage and work with the light board operator, who will either be seated alongside them at a portable control console or talk via headset to the control room. At the tech table, the LD will generally use a Magic Sheet, which is a pictorial layout of how the lights relate to the stage, so they can have quick access to channel numbers that control particular lighting instruments. The LD may also have a copy of the light plot and channel hookup, a remote lighting console, a computer monitor connected to the light board (so they can see what the board op is doing), and a headset, though in smaller theatres this is less common. There may be a time allowed for pre-lighting or "pre-cueing", a practice that is often done with people known as Light Walkers who stand in for performers so the LD can see what the light looks like on bodies. At an arranged time, the performers arrive and the production is worked through in chronological order, with occasional stops to correct sound, lighting, entrances, etc.; known as a "cue-to-cue" or tech rehearsal. The lighting designer will work constantly with the board operator to refine the lighting states as the technical rehearsal continues, but because the focus of a "tech" rehearsal is the production's technical aspects, the LD may require the performers to pause ("hold") frequently. Nevertheless, any errors of focusing or changes to the lighting plan are corrected only when the performers are not onstage. These changes take place during 'work' or 'note' calls. The LD only attends these notes calls if units are hung or rehung and require additional focusing. The LD or assistant lighting director (also known as the ALD, see below for description) will be in charge if in attendance. If the only work to be done is maintenance (i.e. changing a lamp or burnt out gel) then the production or master electrician will be in charge and will direct the electrics crew.
After the tech process, the performance may (or may not, depending on time constraints) go into dress rehearsal without a ticketed audience or previews with a ticketed audience. During this time, if the cueing is finished, the LD will sit in the audience and take notes on what works and what needs changing. At this point, the stage manager will begin to take over the work of calling cues for the light board op to follow. Generally, the LD will stay on the headset, and may still have a monitor connected to the light board in case of problems, or will be in the control booth with the board operator when a monitor is not available. Changes will often occur during notes call, but if serious problems occur, the performance may be halted and the issue will be resolved.
Once the show is open to the public, the lighting designer will often stay and watch several performances of the show, making notes each night and making desired changes the next day during notes call. If the show is still in previews, then the LD will make changes, but once the production officially opens, normally, the lighting designer will not make further changes.
Changes should not be made after the lighting design is finished, and never without the LD's approval. There may be times when changes are necessary after the production has officially opened. Reasons for changes after opening night include: casting changes; significant changes in blocking; addition, deletion or rearrangement of scenes; or the tech and/or preview period (if there was a preview period) was too short to accommodate as thorough a cueing as was needed (this is particularly common in dance productions). If significant changes need to be made, the LD will come in and make them, however, if only smaller changes are needed, the LD may opt to send the ALD. If a show runs for a particularly long time then the LD may come in periodically to check the focus of each lighting instrument and if they are retaining their color (some gel, especially saturated gel, loses its richness and can fade or 'burn out' over time). The LD may also sit in on a performance to make sure that the cues are still being called at the right place and time. The goal is often to finish by the opening of the show, but what is most important is that the LD and the directors believe that the design is finished to each's satisfaction. If that happens to be by opening night, then after opening no changes are normally made to that particular production run at that venue. The general maintenance of the lighting rig then becomes the responsibility of the master electrician.
== In small theatres ==
It is uncommon for a small theatre to have a very large technical crew, as there is less work to do. Many times, the lighting crew of a small theater will consist of a single lighting designer and one to three people, who collectively are in charge of hanging, focusing, and patching all lighting instruments. The lighting designer, in this situation, commonly works directly with this small team, fulfilling the role of both master electrician and lighting designer. Many times the designer will directly participate in the focusing of lights. The same crew will generally also program cues and operate the light board during rehearsals and performances. In some cases, the light board and sound board are operated by the same person, depending on the complexity of the show. The lighting designer may also take on other roles in addition to lights when they are finished hanging lights and programming cues on the board.
== Advances in visualization and presentation ==
As previously mentioned, it is difficult to fully communicate the intent of a lighting design before all the lights are installed and all the cues are written. With the advancement in computer processing and visualization software, lighting designers are now able to create computer-generated images (CGI) that represent their ideas. The lighting designer enters the light plot into the visualization software and then enters the ground plan of the theater and set design, giving as much three-dimensional data as possible (which helps in creating complete renderings). This creates a 3D model in computer space that can be lit and manipulated. Using the software, the LD can use the lights from his plot to create actual lighting in the 3D model with the ability to define parameters such as color, focus, gobo, beam angle etc. The designer can then take renderings or "snapshots" of various looks that can then be printed out and shown to the director and other members of the design team.
== Mockups and lighting scale models ==
In addition to computer visualization, either full-scale or small-scale mockups are a good method for depicting a lighting designer's ideas. Fiber optic systems such as LightBox or Luxam allow a users to light a scale model of the set. For example, a set designer can create a model of the set in 1/4" scale, and the lighting designer can then take the fiber optic cables and attach them to scaled-down lighting units that can accurately replicate the beam angles of specified lighting fixtures. These 'mini lights' can then be attached to cross pieces simulating different lighting positions. Fiber optic fixtures have the capacity to simulate attributes of full scale theatrical lighting fixtures including; color, beam angle, intensity, and gobos. The most sophisticated fiber optic systems are controllable through computer software or a DMX controlled Light board. This gives the lighting designer the ability to mock up real-time lighting effects as they will look during the show.
== Additional members of the lighting design team ==
If the production is large or especially complex, the lighting designer may hire additional lighting professionals to help execute the design.
=== Associate lighting designer ===
The associate lighting designer (associate LD) will assist the lighting designer in creating and executing the lighting design. While the duties that an LD may expect the associate LD to perform may differ from person to person, usually the Ass't LD will do the following:
Attend design and production meetings with or in place of the LD
Attend rehearsals with or in place of LD and take notes of specific design ideas and tasks that the lighting department needs to accomplish
Assist the LD in generating the light plot, channel hookup and sketches
If needed, the Associate may need to take the set drawings and put them into a CAD program to be manipulated by the LD (however, this job is usually given to the assistant LD if there is one).
The assistant LD may be in charge of running focus, and may even direct where the lights are to be focused.
The associate is generally authorized to speak on behalf of the LD and can make creative and design decisions when needed (and when authorized by the LD). This is one of the biggest differences between the Associate and the Assistant.
=== Assistant lighting designer ===
The assistant lighting designer (assistant LD) assists the lighting designer and associate lighting designer. Depending on the particular arrangement the ALD may report directly to the LD, or they may in essence be the Associate's assistant. There also may be more than one assistant on a show depending on the size of the production. The ALD will usually:
Attend design and production meetings with the LD or the associate LD
Attend rehearsals with the LD or the associate LD
Assist the LD in generating the light plot and channel hookup. If the plot is to be computer generated, the ALD is the one who physically enters the information into the computer.
The ALD may run errands for the LD such as picking up supplies or getting the light plot printed in large format.
The ALD will help the Associate LD in running focus.
The ALD may take Focus Charts during focus.
Track and coordinate followspots (if any exist for the production) and generate paperwork to aid in their cueing and color changes.
In rare instances the ALD may be the light board operator.
== See also ==
List of lighting designers
Architectural lighting design
Landscape lighting
Master electrician
Professional Lighting and Sound Association
== References ==
Stage Lighting Design: The Art, the Craft, the Life, by Richard Pilbrow on books.google.com
Stage Lighting Design: A Practical Guide, Neil Fraser, on books.google.com
A Practical Guide to Stage Lighting, By Steven Louis Shelley, on books.google.com
The Lighting Art: The Aesthetics of Stage Lighting Design, by Richard H. Palmer, on books.google.com
Stage lighting design in Britain: the emergence of the lighting designer, 1881-1950, by Nigel H. Morgan, on books.google.com
Scene Design and Stage Lighting By R. Wolf, Dick Block, on books.google.com
== External links ==
stagelightingprimer.com,Stage Lighting for Students
northern.edu, A brief history of stage lighting | Wikipedia/Lighting_designer |
In mathematics, the biharmonic equation is a fourth-order partial differential equation which arises in areas of continuum mechanics, including linear elasticity theory and the solution of Stokes flows. Specifically, it is used in the modeling of thin structures that react elastically to external forces.
== Notation ==
It is written as
∇
4
φ
=
0
{\displaystyle \nabla ^{4}\varphi =0}
or
∇
2
∇
2
φ
=
0
{\displaystyle \nabla ^{2}\nabla ^{2}\varphi =0}
or
Δ
2
φ
=
0
{\displaystyle \Delta ^{2}\varphi =0}
where
∇
4
{\displaystyle \nabla ^{4}}
, which is the fourth power of the del operator and the square of the Laplacian operator
∇
2
{\displaystyle \nabla ^{2}}
(or
Δ
{\displaystyle \Delta }
), is known as the biharmonic operator or the bilaplacian operator. In Cartesian coordinates, it can be written in
n
{\displaystyle n}
dimensions as:
∇
4
φ
=
∑
i
=
1
n
∑
j
=
1
n
∂
i
∂
i
∂
j
∂
j
φ
=
(
∑
i
=
1
n
∂
i
∂
i
)
(
∑
j
=
1
n
∂
j
∂
j
)
φ
.
{\displaystyle \nabla ^{4}\varphi =\sum _{i=1}^{n}\sum _{j=1}^{n}\partial _{i}\partial _{i}\partial _{j}\partial _{j}\varphi =\left(\sum _{i=1}^{n}\partial _{i}\partial _{i}\right)\left(\sum _{j=1}^{n}\partial _{j}\partial _{j}\right)\varphi .}
Because the formula here contains a summation of indices, many mathematicians prefer the notation
Δ
2
{\displaystyle \Delta ^{2}}
over
∇
4
{\displaystyle \nabla ^{4}}
because the former makes clear which of the indices of the four nabla operators are contracted over.
For example, in three dimensional Cartesian coordinates the biharmonic equation has the form
∂
4
φ
∂
x
4
+
∂
4
φ
∂
y
4
+
∂
4
φ
∂
z
4
+
2
∂
4
φ
∂
x
2
∂
y
2
+
2
∂
4
φ
∂
y
2
∂
z
2
+
2
∂
4
φ
∂
x
2
∂
z
2
=
0.
{\displaystyle {\partial ^{4}\varphi \over \partial x^{4}}+{\partial ^{4}\varphi \over \partial y^{4}}+{\partial ^{4}\varphi \over \partial z^{4}}+2{\partial ^{4}\varphi \over \partial x^{2}\partial y^{2}}+2{\partial ^{4}\varphi \over \partial y^{2}\partial z^{2}}+2{\partial ^{4}\varphi \over \partial x^{2}\partial z^{2}}=0.}
As another example, in n-dimensional real coordinate space without the origin
(
R
n
∖
0
)
{\displaystyle \left(\mathbb {R} ^{n}\setminus \mathbf {0} \right)}
,
∇
4
(
1
r
)
=
3
(
15
−
8
n
+
n
2
)
r
5
{\displaystyle \nabla ^{4}\left({1 \over r}\right)={3(15-8n+n^{2}) \over r^{5}}}
where
r
=
x
1
2
+
x
2
2
+
⋯
+
x
n
2
.
{\displaystyle r={\sqrt {x_{1}^{2}+x_{2}^{2}+\cdots +x_{n}^{2}}}.}
which shows, for n=3 and n=5 only,
1
r
{\displaystyle {\frac {1}{r}}}
is a solution to the biharmonic equation.
A solution to the biharmonic equation is called a biharmonic function. Any harmonic function is biharmonic, but the converse is not always true.
In two-dimensional polar coordinates, the biharmonic equation is
1
r
∂
∂
r
(
r
∂
∂
r
(
1
r
∂
∂
r
(
r
∂
φ
∂
r
)
)
)
+
2
r
2
∂
4
φ
∂
θ
2
∂
r
2
+
1
r
4
∂
4
φ
∂
θ
4
−
2
r
3
∂
3
φ
∂
θ
2
∂
r
+
4
r
4
∂
2
φ
∂
θ
2
=
0
{\displaystyle {\frac {1}{r}}{\frac {\partial }{\partial r}}\left(r{\frac {\partial }{\partial r}}\left({\frac {1}{r}}{\frac {\partial }{\partial r}}\left(r{\frac {\partial \varphi }{\partial r}}\right)\right)\right)+{\frac {2}{r^{2}}}{\frac {\partial ^{4}\varphi }{\partial \theta ^{2}\partial r^{2}}}+{\frac {1}{r^{4}}}{\frac {\partial ^{4}\varphi }{\partial \theta ^{4}}}-{\frac {2}{r^{3}}}{\frac {\partial ^{3}\varphi }{\partial \theta ^{2}\partial r}}+{\frac {4}{r^{4}}}{\frac {\partial ^{2}\varphi }{\partial \theta ^{2}}}=0}
which can be solved by separation of variables. The result is the Michell solution.
== 2-dimensional space ==
The general solution to the 2-dimensional case is
x
v
(
x
,
y
)
−
y
u
(
x
,
y
)
+
w
(
x
,
y
)
{\displaystyle xv(x,y)-yu(x,y)+w(x,y)}
where
u
(
x
,
y
)
{\displaystyle u(x,y)}
,
v
(
x
,
y
)
{\displaystyle v(x,y)}
and
w
(
x
,
y
)
{\displaystyle w(x,y)}
are harmonic functions and
v
(
x
,
y
)
{\displaystyle v(x,y)}
is a harmonic conjugate of
u
(
x
,
y
)
{\displaystyle u(x,y)}
.
Just as harmonic functions in 2 variables are closely related to complex analytic functions, so are biharmonic functions in 2 variables. The general form of a biharmonic function in 2 variables can also be written as
Im
(
z
¯
f
(
z
)
+
g
(
z
)
)
{\displaystyle \operatorname {Im} ({\bar {z}}f(z)+g(z))}
where
f
(
z
)
{\displaystyle f(z)}
and
g
(
z
)
{\displaystyle g(z)}
are analytic functions.
== See also ==
Harmonic function
== References ==
== External links ==
Weisstein, Eric W. "Biharmonic Equation". MathWorld.
Weisstein, Eric W. "Biharmonic Operator". MathWorld. | Wikipedia/Biharmonic_equation |
Used in hydrogeology, the groundwater flow equation is the mathematical relationship which is used to describe the flow of groundwater through an aquifer. The transient flow of groundwater is described by a form of the diffusion equation, similar to that used in heat transfer to describe the flow of heat in a solid (heat conduction). The steady-state flow of groundwater is described by a form of the Laplace equation, which is a form of potential flow and has analogs in numerous fields.
The groundwater flow equation is often derived for a small representative elemental volume (REV), where the properties of the medium are assumed to be effectively constant. A mass balance is done on the water flowing in and out of this small volume, the flux terms in the relationship being expressed in terms of head by using the constitutive equation called Darcy's law, which requires that the flow is laminar. Other approaches are based on Agent Based Models to incorporate the effect of complex aquifers such as karstic or fractured rocks (i.e. volcanic)
== Mass balance ==
A mass balance must be performed, and used along with Darcy's law, to arrive at the transient groundwater flow equation. This balance is analogous to the energy balance used in heat transfer to arrive at the heat equation. It is simply a statement of accounting, that for a given control volume, aside from sources or sinks, mass cannot be created or destroyed. The conservation of mass states that, for a given increment of time (Δt), the difference between the mass flowing in across the boundaries, the mass flowing out across the boundaries, and the sources within the volume, is the change in storage.
Δ
M
s
t
o
r
Δ
t
=
M
i
n
Δ
t
−
M
o
u
t
Δ
t
−
M
g
e
n
Δ
t
{\displaystyle {\frac {\Delta M_{stor}}{\Delta t}}={\frac {M_{in}}{\Delta t}}-{\frac {M_{out}}{\Delta t}}-{\frac {M_{gen}}{\Delta t}}}
== Diffusion equation (transient flow) ==
Mass can be represented as density times volume, and under most conditions, water can be considered incompressible (density does not depend on pressure). The mass fluxes across the boundaries then become volume fluxes (as are found in Darcy's law). Using Taylor series to represent the in and out flux terms across the boundaries of the control volume, and using the divergence theorem to turn the flux across the boundary into a flux over the entire volume, the final form of the groundwater flow equation (in differential form) is:
S
s
∂
h
∂
t
=
−
∇
⋅
q
−
G
.
{\displaystyle S_{s}{\frac {\partial h}{\partial t}}=-\nabla \cdot q-G.}
This is known in other fields as the diffusion equation or heat equation, it is a parabolic partial differential equation (PDE). This mathematical statement indicates that the change in hydraulic head with time (left hand side) equals the negative divergence of the flux (q) and the source terms (G). This equation has both head and flux as unknowns, but Darcy's law relates flux to hydraulic heads, so substituting it in for the flux (q) leads to
S
s
∂
h
∂
t
=
−
∇
⋅
(
−
K
∇
h
)
−
G
.
{\displaystyle S_{s}{\frac {\partial h}{\partial t}}=-\nabla \cdot (-K\nabla h)-G.}
Now if hydraulic conductivity (K) is spatially uniform and isotropic (rather than a tensor), it can be taken out of the spatial derivative, simplifying them to the Laplacian, this makes the equation
S
s
∂
h
∂
t
=
K
∇
2
h
−
G
.
{\displaystyle S_{s}{\frac {\partial h}{\partial t}}=K\nabla ^{2}h-G.}
Dividing through by the specific storage (Ss), puts hydraulic diffusivity (α = K/Ss or equivalently, α = T/S) on the right hand side. The hydraulic diffusivity is proportional to the speed at which a finite pressure pulse will propagate through the system (large values of α lead to fast propagation of signals). The groundwater flow equation then becomes
∂
h
∂
t
=
α
∇
2
h
−
G
.
{\displaystyle {\frac {\partial h}{\partial t}}=\alpha \nabla ^{2}h-G.}
Where the sink/source term, G, now has the same units but is divided by the appropriate storage term (as defined by the hydraulic diffusivity substitution).
=== Rectangular cartesian coordinates ===
Especially when using rectangular grid finite-difference models (e.g. MODFLOW, made by the USGS), we deal with Cartesian coordinates. In these coordinates the general Laplacian operator becomes (for three-dimensional flow) specifically
∂
h
∂
t
=
α
[
∂
2
h
∂
x
2
+
∂
2
h
∂
y
2
+
∂
2
h
∂
z
2
]
−
G
.
{\displaystyle {\frac {\partial h}{\partial t}}=\alpha \left[{\frac {\partial ^{2}h}{\partial x^{2}}}+{\frac {\partial ^{2}h}{\partial y^{2}}}+{\frac {\partial ^{2}h}{\partial z^{2}}}\right]-G.}
MODFLOW code discretizes and simulates an orthogonal 3-D form of the governing groundwater flow equation. However, it has an option to run in a "quasi-3D" mode if the user wishes to do so; in this case the model deals with the vertically averaged T and S, rather than k and Ss. In the quasi-3D mode, flow is calculated between 2D horizontal layers using the concept of leakage.
=== Circular cylindrical coordinates ===
Another useful coordinate system is 3D cylindrical coordinates (typically where a pumping well is a line source located at the origin — parallel to the z axis — causing converging radial flow). Under these conditions the above equation becomes (r being radial distance and θ being angle),
∂
h
∂
t
=
α
[
∂
2
h
∂
r
2
+
1
r
∂
h
∂
r
+
1
r
2
∂
2
h
∂
θ
2
+
∂
2
h
∂
z
2
]
−
G
.
{\displaystyle {\frac {\partial h}{\partial t}}=\alpha \left[{\frac {\partial ^{2}h}{\partial r^{2}}}+{\frac {1}{r}}{\frac {\partial h}{\partial r}}+{\frac {1}{r^{2}}}{\frac {\partial ^{2}h}{\partial \theta ^{2}}}+{\frac {\partial ^{2}h}{\partial z^{2}}}\right]-G.}
=== Assumptions ===
This equation represents flow to a pumping well (a sink of strength G), located at the origin. Both this equation and the Cartesian version above are the fundamental equation in groundwater flow, but to arrive at this point requires considerable simplification. Some of the main assumptions which went into both these equations are:
the aquifer material is incompressible (no change in matrix due to changes in pressure — aka subsidence),
the water is of constant density (incompressible),
any external loads on the aquifer (e.g., overburden, atmospheric pressure) are constant,
for the 1D radial problem the pumping well is fully penetrating a non-leaky aquifer,
the groundwater is flowing slowly (Reynolds number less than unity), and
the hydraulic conductivity (K) is an isotropic scalar.
Despite these large assumptions, the groundwater flow equation does a good job of representing the distribution of heads in aquifers due to a transient distribution of sources and sinks.
== Laplace equation (steady-state flow) ==
If the aquifer has recharging boundary conditions a steady-state may be reached (or it may be used as an approximation in many cases), and the diffusion equation (above) simplifies to the Laplace equation.
0
=
α
∇
2
h
{\displaystyle 0=\alpha \nabla ^{2}h}
This equation states that hydraulic head is a harmonic function, and has many analogs in other fields. The Laplace equation can be solved using techniques, using similar assumptions stated above, but with the additional requirements of a steady-state flow field.
A common method for solution of this equations in civil engineering and soil mechanics is to use the graphical technique of drawing flownets; where contour lines of hydraulic head and the stream function make a curvilinear grid, allowing complex geometries to be solved approximately.
Steady-state flow to a pumping well (which never truly occurs, but is sometimes a useful approximation) is commonly called the Thiem solution.
== Two-dimensional groundwater flow ==
The above groundwater flow equations are valid for three dimensional flow. In unconfined aquifers, the solution to the 3D form of the equation is complicated by the presence of a free surface water table boundary condition: in addition to solving for the spatial distribution of heads, the location of this surface is also an unknown. This is a non-linear problem, even though the governing equation is linear.
An alternative formulation of the groundwater flow equation may be obtained by invoking the Dupuit–Forchheimer assumption, where it is assumed that heads do not vary in the vertical direction (i.e.,
∂
h
/
∂
z
=
0
{\displaystyle \partial h/\partial z=0}
). A horizontal water balance is applied to a long vertical column with area
δ
x
δ
y
{\displaystyle \delta x\delta y}
extending from the aquifer base to the unsaturated surface. This distance is referred to as the saturated thickness, b. In a confined aquifer, the saturated thickness is determined by the height of the aquifer, H, and the pressure head is non-zero everywhere. In an unconfined aquifer, the saturated thickness is defined as the vertical distance between the water table surface and the aquifer base. If
∂
h
/
∂
z
=
0
{\displaystyle \partial h/\partial z=0}
, and the aquifer base is at the zero datum, then the unconfined saturated thickness is equal to the head, i.e., b=h.
Assuming both the hydraulic conductivity and the horizontal components of flow are uniform along the entire saturated thickness of the aquifer (i.e.,
∂
q
x
/
∂
z
=
0
{\displaystyle \partial q_{x}/\partial z=0}
and
∂
K
/
∂
z
=
0
{\displaystyle \partial K/\partial z=0}
), we can express Darcy's law in terms of integrated groundwater discharges, Qx and Qy:
Q
x
=
∫
0
b
q
x
d
z
=
−
K
b
∂
h
∂
x
{\displaystyle Q_{x}=\int _{0}^{b}q_{x}dz=-Kb{\frac {\partial h}{\partial x}}}
Q
y
=
∫
0
b
q
y
d
z
=
−
K
b
∂
h
∂
y
{\displaystyle Q_{y}=\int _{0}^{b}q_{y}dz=-Kb{\frac {\partial h}{\partial y}}}
Inserting these into our mass balance expression, we obtain the general 2D governing equation for incompressible saturated groundwater flow:
∂
n
b
∂
t
=
∇
⋅
(
K
b
∇
h
)
+
N
.
{\displaystyle {\frac {\partial nb}{\partial t}}=\nabla \cdot (Kb\nabla h)+N.}
Where n is the aquifer porosity. The source term, N (length per time), represents the addition of water in the vertical direction (e.g., recharge). By incorporating the correct definitions for saturated thickness, specific storage, and specific yield, we can transform this into two unique governing equations for confined and unconfined conditions:
S
∂
h
∂
t
=
∇
⋅
(
K
b
∇
h
)
+
N
.
{\displaystyle S{\frac {\partial h}{\partial t}}=\nabla \cdot (Kb\nabla h)+N.}
(confined), where S=Ssb is the aquifer storativity and
S
y
∂
h
∂
t
=
∇
⋅
(
K
h
∇
h
)
+
N
.
{\displaystyle S_{y}{\frac {\partial h}{\partial t}}=\nabla \cdot (Kh\nabla h)+N.}
(unconfined), where Sy is the specific yield of the aquifer.
Note that the partial differential equation in the unconfined case is non-linear, whereas it is linear in the confined case. For unconfined steady-state flow, this non-linearity may be removed by expressing the PDE in terms of the head squared:
∇
⋅
(
K
∇
h
2
)
=
−
2
N
.
{\displaystyle \nabla \cdot (K\nabla h^{2})=-2N.}
Or, for homogeneous aquifers,
∇
2
h
2
=
−
2
N
K
.
{\displaystyle \nabla ^{2}h^{2}=-{\frac {2N}{K}}.}
This formulation allows us to apply standard methods for solving linear PDEs in the case of unconfined flow. For heterogeneous aquifers with no recharge, Potential flow methods may be applied for mixed confined/unconfined cases.
== See also ==
Analytic element method
A numerical method used for the solution of partial differential equations
Dupuit–Forchheimer assumption
A simplification of the groundwater flow equation regarding vertical flow
Groundwater energy balance
Groundwater flow equations based on the energy balance
Richards equation
== References ==
== Further reading ==
H. F. Wang and M.P. Anderson Introduction to Groundwater Modeling: Finite Difference and Finite Element Methods
An excellent beginner's read for groundwater modeling. Covers all the basic concepts, with simple examples in FORTRAN 77.
Freeze, R. Allan; Cherry, John A. (1979). Groundwater Archived 2020-04-06 at the Wayback Machine. Prentice Hall. ISBN 978-0133653120.
== External links ==
USGS groundwater software — free groundwater modeling software like MODFLOW
Groundwater Hydrology (MIT OpenCourseware) | Wikipedia/Groundwater_flow_equation |
Juniper Networks, Inc. is an American multinational corporation headquartered in Sunnyvale, California. The company develops and markets networking products, including routers, switches, network management software, network security products, and software-defined networking technology.
The company was founded in 1996 by Pradeep Sindhu, with Scott Kriens as the first CEO, who remained until September 2008. Kriens has been credited with much of Juniper's early market success. It received several rounds of funding from venture capitalists and telecommunications companies before going public in 1999. Juniper grew to $673 million in annual revenues by 2000. By 2001 it had a 37% share of the core routers market, challenging Cisco's once-dominant market-share. It grew to US$4 billion in revenues by 2004 and $4.63 billion in 2014. Juniper appointed Kevin Johnson as CEO in 2008, Shaygan Kheradpir in 2013 and Rami Rahim in 2014.
Juniper Networks originally focused on core routers, which are used by internet service providers (ISPs) to perform IP address lookups and direct internet traffic. Through the acquisition of Unisphere, in 2002, the company entered the market for edge routers, which are used by ISPs to route internet traffic to individual consumers. In 2003, Juniper entered the IT security market with its own JProtect security toolkit before acquiring security company NetScreen Technologies the following year. In the early 2000s, Juniper entered the enterprise segment, which accounted for one-third of its revenues by 2005. Since 2014, Juniper has been focused on developing new software-defined networking products. In early 2024, Juniper agreed to be bought out by Hewlett Packard Enterprise (HPE) for approximately $14 billion.
== History ==
=== Origins and funding ===
Pradeep Sindhu, a scientist with Xerox's Palo Alto Research Center (PARC), conceived the idea for Juniper Networks while on vacation in 1995
and founded the company in February 1996. Sindhu wanted to create data packet-based routers that were optimized for Internet traffic (packet switching), whereby the routing and transferring of data occurs "by means of addressed packets so that a channel is occupied during the transmission of the packet only, and upon completion of the transmission the channel is made available for the transfer of other traffic." He was joined by engineers Bjorn Liencres from Sun Microsystems and Dennis Ferguson from MCI Communications.
Sindhu started Juniper Networks with $2 million in seed funding, which was followed by $12 million in funding in the company's first year of operations. About seven months after the company's founding, Scott Kriens was appointed CEO to manage the business, while founder Sindhu became the Chief Technology Officer. By February 1997, Juniper had raised $8 million in venture funding. Later that year, Juniper Networks raised an additional $40 million in investments from a round that included four out of five of the largest telecommunications equipment manufacturers: Siemens, Ericsson, Nortel and 3Com. Juniper also received $2.5 million from Qwest and other investments from AT&T.
=== Growth and IPO ===
Juniper Networks had $3.8 million in annual revenue in 1998. By the following year, its only product, the M40 router, was being used by 50 telecommunications companies. Juniper Networks signed agreements with Alcatel and Ericsson to distribute the M40 internationally. A European headquarters was established in the United Kingdom and an Asia-Pacific headquarters in Hong Kong. A subsidiary was created in Japan and offices were established in Korea in 1999. Juniper Networks's market share for core routers grew from 6% in 1998 to 17.5% one year later, and 20% by April 2000.
Juniper Networks filed for an initial public offering in April 1999 and its first day on the NASDAQ was that June. The stock set a record in first-day trading in the technology sector by increasing 191% to a market capitalization of $4.9 billion. According to Telephony, Juniper Networks became the "latest darling of Wall Street", reaching a $7 billion valuation by late July. Within a year, the company's stock grew five-fold.
Juniper Networks's revenues grew 600% in 2000 to $673 million. That same year, Juniper Networks moved its headquarters from Mountain View to Sunnyvale, California.
=== Competition ===
By 2001, Juniper controlled one-third of the market for high-end core routers, mostly at the expense of Cisco Systems sales. According to Businessweek, "analysts unanimously agree[d] that Juniper's boxes [were] technically superior to Cisco's because the hardware does most of the data processing. Cisco routers still relied on software, which often results in slower speeds." However, Cisco provided a broader range of services and support and had an entrenched market position. The press often depicted Juniper and Cisco as a "David versus Goliath" story. Cisco had grown through acquisitions to be a large generalist vendor for routing equipment in homes, businesses and for ISPs, whereas Juniper was thought of as the "anti-Cisco" for being a small company with a narrow focus.
In January 2001, Cisco introduced a suite of router products that Businessweek said was intended to challenge Juniper's increasing market-share. According to Businessweek, Juniper's top-end router was four times as fast at only twice the cost of comparable Cisco products. Cisco's routers were not expected to erode Juniper's growing share of the market, but other companies such as Lucent, Alcatel, and startups Avici Systems and Pluris had announced plans to release products that would out-pace Juniper's routers.
Juniper introduced a suite of routers for the network edge that allowed it to compete with Cisco. Juniper's edge routers had a 9% market share two months after release. Both companies made exaggerated marketing claims; Juniper promoted its products as stable enough to make IT staff bored and Cisco announced lab tests from Light Reading proved its products were superior to Juniper, whereas the publication itself reached the opposite conclusion. By 2002, both companies were repeatedly announcing products with faster specifications than the other in what Network World called a "'speeds-and-feeds' public relations contest".
By 2004, Juniper controlled 38% of the core router market. By 2007, it had a 5%, 18% and 30% share of the market for enterprise, edge and core routers respectively. Alcatel-Lucent was unsuccessful in challenging Juniper in the core router market but continued competing with Juniper in edge routers along with Cisco.
=== Further development ===
In late 2000, Juniper formed a joint venture with Ericsson to develop and market network switches for internet traffic on mobile devices, and with Nortel for fiber optic technology. In 2001, Juniper introduced a technical certification program and was involved in the first optical internet network in China.: 12 Juniper's growth slowed in 2001 as the telecommunications sector experienced a slowdown and revenues fell by two-thirds during the dot-com bust. 9 to 10% of its workforce was laid off.
Juniper had rebounded by 2004, surpassing $1 billion in revenues for the first time that year and reaching $2 billion in revenue in 2005. Beginning in 2004, with the acquisition of NetScreen, Juniper Networks began developing and marketing products for the enterprise segment. Juniper had a reputation for serving ISPs, not enterprises, which it was trying to change. By 2005, enterprise customers accounted for one-third of the company's revenues, but it had spent $5 billion in acquisitions and R&D for the enterprise market.
In 2006, more than 200 US companies restated their financial results due to a series of investigations into stock backdating practices. Juniper stockholders alleged the company engaged in deceptive backdating practices that benefited its top executives unfairly. In December 2006, Juniper restated its financials, charging $900 million in expenses to correct backdated stock options from 1999 to 2003. This was followed by a $169 million settlement with stockholders in February 2010.
=== 2008–present ===
In July 2008, Juniper's first CEO, Scott Kriens, became chairman and former Microsoft executive Kevin Johnson was appointed CEO. Johnson focused the company more on software, creating a software solutions division headed by a former Microsoft colleague, Bob Muglia. Juniper also hired other former Microsoft executives to focus on the company's software strategy and encourage developers to create software products that run on the Junos operating system. Juniper established partnerships with IBM, Microsoft and Oracle for software compatibility efforts. The SSL/VPN Pulse product family was launched in 2010, then later spun off to a private equity firm in 2014 for $250 million.
In 2012, Juniper laid off 5% of its staff and four of its high-ranking executives departed. The following year, CEO Kevin Johnson announced he was retiring once a replacement was found. In November 2013, Juniper Networks announced that Shaygan Kheradpir would be appointed as the new CEO. He started the position in January 2014.
In January 2014, hedge fund, activist investor and Juniper shareholder Elliott Associates advocated that Juniper reduce its cash reserves and cut costs, before Kheradpir was officially appointed. That February, Juniper reached an agreement with Elliott and other stakeholders for an Integrated Operating Plan (IOP) that involved repurchasing $2 billion in shares, reducing operating expenses by $160 million and appointing two new directors to its board. That April, 6% of the company's staff were laid off to cut expenses. In November 2014, Kheradpir unexpectedly resigned following a review by Juniper's board of directors regarding his conduct in a negotiation with an unnamed Juniper customer. An internal Juniper executive, Rami Rahim, took his place as CEO.
In May 2014, Palo Alto Networks agreed to pay a $175 million settlement for allegedly infringing on Juniper's patents for application firewalls.
In 2015, Wired magazine reported that the company announced it had found unauthorized code that enabled backdoors into its ScreenOS products. The code was patched with updates from the company.
In January 2024, the company agreed to be purchased by Hewlett Packard Enterprise (HPE) for $14 billion in an all-cash deal to boost HPE's networking and artificial intelligence resources. The acquisition was contested by the U.S. Department of Justice in January 2025, citing concerns about reduced competition and innovation, leading to higher prices for consumers.
== Acquisitions and investments ==
By 2001, Juniper had made only a few acquisitions of smaller companies, due to the leadership's preference for organic growth. The pace of acquisition picked up in 2001 and 2002 with the purchases of Pacific Broadband and Unisphere Networks. In 2004 Juniper made a $4 billion acquisition of network security company NetScreen Technologies. Juniper revised NetScreen's channel program that year and used its reseller network to bring other products to market.
Juniper made five acquisitions in 2005, mostly of startups with deal values ranging from $8.7 to $337 million. It acquired application-acceleration vendor Redline Networks, VOIP company Kagoor Networks, as well as wide area network (WAN) company Peribit Networks. Peribit and Redline were incorporated into a new application products group and their technology was integrated into Juniper's infranet framework. Afterwards, Juniper did not make any additional acquisitions until 2010.
From 2010 to September 2011, Juniper made six acquisitions and invested in eight companies. Often Juniper acquired early-stage startups, developing their technology, then selling it to pre-existing Juniper clients. Juniper acquired two digital video companies, Ankeena Networks and Blackwave Inc., as well as wireless LAN software company Trapeze Networks. In 2012, Juniper acquired Mykonos Software, which develops security software intended to deceive hackers already within the network perimeter. and a developer of software-defined network controllers, Contrail Systems. In 2014, Juniper acquired the software-defined networking (SDN) company WANDL.
In April 2016, Juniper closed its acquisition of BTI, a provider of cloud and metro network technology, in an effort to beef up its data center interconnect and metro packet optical transport technology and services. Juniper acquired cloud operations management and optimization startup AppFormix in December 2016. In 2017, Juniper bought Cyphort, a Silicon Valley startup that makes security analytics software. Juniper acquired cloud storage company HTBASE in November 2018. In April 2019, Juniper acquired wireless LAN (WLAN) startup Mist Systems to bolster its software-defined enterprise portfolio and multicloud offerings. In February 2022, it was announced Juniper had acquired WiteSand, a specialist cloud-native zero trust network access control (NAC) solutions company.
== Products ==
Juniper Networks designs and markets IT networking products, such as routers, switches and IT security products. It started out selling core routers for ISPs, and expanded into edge routers, data centers, wireless networking, networking for branch offices and other access and aggregation devices.
Juniper is the third largest market-share holder overall for routers and switches used by ISPs. According to analyst firm Dell'Oro Group, it is the fourth largest for edge routers and second for core routers with 25% of the core market. It is also the second largest market share holder for firewall products with a 24.8% share of the firewall market. In data center security appliances, Juniper is the second-place market-share holder behind Cisco. Juniper provides technical support and services through the J-Care program.
As of February 2020, Juniper's product families include the following:
=== Routers and switches ===
Juniper Networks' first product was the Junos router operating system, which was released on July 1, 1998. The first Juniper router was made available that September and was a core router for internet service providers called the M40.: 8 It incorporated specialized application-specific integrated circuits (ASIC) for routing internet traffic that were developed in partnership with IBM. It had ten times the throughput of comparable contemporary Cisco products. The M40 was followed by the smaller M20 router in December 1999 and the M160 in March 2000.
By 2000, Juniper had developed five hardware systems and made seven new releases of its Junos operating system. That April, Juniper released the second generation of the internet processors embedded in its core routers. In April 2002, Juniper released the first of the T-series family (originally known under the code-name Gibson), which could perform four times as many route lookups per second as the M160. The first products of the TX Matrix family, which could be used to combine up to four T-series routers, was released in December 2004.
By 2003, Juniper had diversified into three major router applications: core routers, edge routers and routers for mobile traffic.: 9 Juniper's first major diversification from core routers was when it entered the market for edge routers, by acquiring the e-series product family (originally known as ERX) through the purchase of Unisphere in 2000. By 2002, both Cisco and Juniper had increased their focus on edge routers, because many ISPs had built up abundant bandwidth at the core. Several improvements to Juniper's software and its broadband aggregation features were released in late 2003. At this time, Juniper had the largest market-share (52%) of the broadband aggregation market. In 2003, Juniper entered the market for cable-modem termination systems with the G-series product family after the acquisition of Pacific Broadband. The product family was discontinued later that year.
Juniper's first enterprise switch product was the EX 4200, which was released in 2008. In a comparative technical test, Network World said the EX4200 was the top performer out of network switches they tested in latency and throughput, but its multicast features were "newer and less robust" than other aspects of the product. Juniper Networks announced the T1600 1.6 Terabits per second core router in 2007 and the newer T4000 4 Terabit router in 2010. In 2012, it released the ACX family of universal access routers. In 2013, the company made several new releases in the MX family of edge routers: it introduced a smaller version of its core routers called PTX3000, and several new enterprise routers were released. Seven months later, Juniper acquired WANDL, and its technology was integrated into the NorthStar WAN controller Juniper announced in February 2014.
In February 2011, Juniper introduced QFabric, a proprietary protocol methodology for transferring data over a network using a single network layer. Several individual products for the QFabric methodology were released throughout the year. In October 2013, Juniper introduced another network architecture called MetaFabric and a new set of switches, the QFX5100 family, as one of the foundations of the new architecture.
In February 2014, several software and hardware improvements were introduced for Juniper routers, including a series of software applications ISPs could use to provide internet-based services to consumers. In December 2014, Juniper introduced a network switch, OCX1100, that could run on either the Junos operating system or the Open Compute Project open-source software.
=== Security ===
Juniper Networks introduced the JProtect security toolkit in May 2003. It included firewalls, flow monitoring, filtering and Network Address Translation (NAT). Through the 2004 acquisition of NetScreen Technologies, Juniper acquired the Juniper Secure Meeting product line, as well as remote desktop access software. The NetScreen-5GT ADSL security appliance was the first new NetScreen product Juniper introduced after the acquisition and its first wireless product. The first Juniper product intended for small businesses was a remote access appliance that was released in August 2004. An open interface for the development of third-party tools for the appliance was made available that September.
In September 2004, Juniper entered the market for enterprise access routers with three routers that were the first of the J-series product family. It used the channel partners acquired with NetScreen to take the routers to market. Juniper released its first dedicated NAC product in late 2005, which was followed by the acquisition of Funk Software for its NAC capabilities for switches. According to a 2006 review in Network World, Juniper's SSG 520 firewall and routing product was "the first serious threat" to competing products from Cisco. Juniper released the SRX family of gateway products in 2008. The gateways sold well, but customers and resellers reported a wide range of technical issues starting in 2010, which Juniper did not acknowledge until 2012, when it began providing updates to the product software.
In August 2011, Juniper and AT&T announced they would jointly develop the AT&T Mobile Security application based on Juniper's Pulse security software. In May 2012, Juniper released a series of new features for the web security software it acquired from Mykonos Software that February. Mykonos' software is focused on deceiving hackers by presenting fake vulnerabilities and tracking their activity. In January 2014, Juniper announced the Firefly Suite of security and switching products for virtual machines. The following month Juniper Networks released several products for "intrusion deception", which create fake files, store incorrect passwords and change network maps in order to confuse hackers that have already penetrated the network perimeter.
An analysis of Juniper's ScreenOS firmware code in December 2015 discovered a backdoor key using Dual EC DRBG allowing to passively decrypt the traffic encrypted by ScreenOS. This backdoor was inserted in the year 2008 into the versions of ScreenOS from 6.2.0r15 to 6.2.0r18 and from 6.3.0r12 to 6.3.0r20 and gives any user administrative access when using a special master password. Some analysts claim that this backdoor still exists in ScreenOS. Stephen Checkoway was quoted in Wired that "If this backdoor was not intentional, then, in my opinion, it's an amazing coincidence."
In December 2015, Juniper Systems announced that they had discovered "unauthorized code" in the ScreenOS software that underlies their NetScreen devices, present from 2012 onwards. There were two vulnerabilities: One was a simple root password backdoor, and the other one was changing a point in Dual_EC_DRBG so that the attackers presumably had the key to use the preexisting (intentional or unintentional) kleptographic backdoor in ScreenOS to passively decrypt traffic.
=== Software defined networking ===
According to a 2014 SWOT analysis by MarketLine, in recent history Juniper has been focusing on software-defined networking (SDN). It acquired SDN company Contrail Systems in December 2012. The following month Juniper announced its SDN strategy, which included a new licensing model based on usage and new features for the Junos operating system. In February 2013, Juniper released several SDN products, including the application provisioning software, Services Activation Director and the Mobile Control Gateway appliance.
In May 2013, Juniper announced an SDN controller called JunosV Contrail, using technology it acquired through Contrail Systems. A series of SDN products were released in February 2014, such as a network management software product, Junos Fusion, and an SDN controller called NorthStar. Northstar helps find the optimal path for data to travel through a network.
Every year, since 2009, Juniper holds SDN Throwdown competition to encourage students from universities across the world to access NorthStar Controller and build a solution around it to optimize network throughput. In the 2019 competition, team led by Sumit Maheshwari (Rutgers University) took first place. Jialu Sun (Santa Clara University) led his team to a second-place finish.
=== Recent updates ===
In March 2015, Juniper announced a series of updates to the PTX family of core routers, the QFX family of switches, as well as updates to its security portfolio. According to a report published by technology consulting firm LexInnova, as of June 2015 Juniper Networks was the third largest recipient of network security-related patents with portfolio of 2,926 security-related patents.
In October 2018, Juniper announced a new offering called EngNet, which is a set of developer tools and information meant to help companies move toward automation, and replace the typical command-line interface.
== Operations ==
Juniper Networks has operations in more than 100 countries. Around 50% of its revenue is from the United States, 30% is from EMEA and 20% is from Asia. Juniper sells directly to businesses, as well as through resale and distribution partners, such as Ericsson, IBM, Nokia, IngramMicro and NEC. About 50% of Juniper's revenues are derived from routers, 13% from switches, 12% comes from IT security and 25% from services.
According to a 2013 report by Glassdoor, Juniper Networks has the highest paid software engineers in the technology sector by a margin of about $24,000 per year. It operates the Juniper Networks Academic Alliance (JNAA) program, which scouts fresh college graduates.
According to a SWOT analysis by MarketLine, Juniper has "a strong focus" on research and development. R&D expenses have been between 22 and 25% of revenue from 2011 to 2013. Most of the company's manufacturing is outsourced to three manufacturing companies: Celestica, Flextronics and Accton Technology. Juniper operates the Junos Innovation Fund, which was started with $50 million in 2010 and invests in early-stage technology companies developing applications for the Junos operating system. As of 2011, Juniper Networks invested in 20 companies. This is estimated to be 1 to 2% of the companies it has evaluated for a potential investment.
== ScreenOS Backdoor ==
In December 2015, Juniper issued an emergency security patch for a backdoor in its security equipment. Together with another vulnerability it allowed to bypass authentication and decrypt VPN traffic on ScreenOS. Analysis showed that the mechanism of the backdoor was created by the NSA, but might later have been taken over by an unnamed national government.
== See also ==
List of networking hardware vendors
== References ==
== External links ==
Official website
Business data for Juniper Networks: | Wikipedia/Juniper_Networks |
Nokia Networks (formerly Nokia Solutions and Networks (NSN) and Nokia Siemens Networks (NSN)) is a Finnish multinational data networking and telecommunications equipment company headquartered in Espoo, Finland, and wholly owned subsidiary of Nokia Corporation. It started as a joint venture between Nokia of Finland and Siemens of Germany known as Nokia Siemens Networks.
Nokia Networks has operations in around 120 countries. In 2013, Nokia acquired 100% of Nokia Networks, buying all of Siemens' shares. In April 2014, the NSN name was phased out as part of a rebranding process.
== History ==
The company was created as the result of a joint venture between Siemens Communications (minus its Enterprise business unit) and Nokia's Network Business. The formation of the company was publicly announced on 19 June 2006. Nokia Siemens Networks was officially launched at the 3GSM World Congress in Barcelona in February 2007. Nokia Siemens Networks then began full operations on 1 April 2007 and has its headquarters in Espoo, Greater Helsinki, Finland.
In January 2008 Nokia Siemens Networks acquired Israeli company Atrica, a company that builds carrier-class Ethernet transport systems for metro networks. The official release did not disclose terms, however they are thought to be in the region of $100 million. In February 2008 Nokia Siemens Networks acquired Apertio, a Bristol, UK-based mobile network customer management tools provider, for €140 million. With this acquisition Nokia Siemens Networks gained customers in the subscriber management area including Orange, T-Mobile, O2, Vodafone, and Hutchison 3G.
In 2009, according to Siemens, Siemens only retained a non-controlling financial interest in NSN, with the day-to-day operations residing with Nokia.
On 19 July 2010, Nokia Siemens Networks announced it would acquire the wireless-network equipment of Motorola. The acquisition was completed on 29 April 2011 for $975 million in cash. As of the transaction approximately 6,900 employees transferred to Nokia Siemens Networks.
On 23 November 2011, Nokia Siemens Networks announced that it would refocus its business on mobile broadband equipment, the fastest-growing segment of the market. This refocus resulted in the restructuring of the company and the planned layoffs of 17,000 employees. The plan reduced the company's work force by 23% from its 2011 level of 74,000, and helped the company trim annual operating expenses by $1.35 billion by the end of 2013.
On 12 December 2011, ADTRAN, Inc. announced it would acquire Nokia Siemens Networks fixed line Broadband Access business. This caused around 400 jobs to move to ADTRAN as part of the deal.
After the restructuring process, Nokia Siemens Networks brought in a positive turn around to its businesses. The bottom line and operating margins rose to approximately 10%, which was a significant shift from the previous sub-zero margins, with positive cash flows for six continuous quarters.
On 7 August 2013, Nokia completed the acquisition of Siemens' stake in the company and rebranded as Nokia Solutions and Networks. After this acquisition NSN became a fully owned subsidiary of Nokia.
On 29 April 2014, Nokia announced that NSN would henceforth be known as Nokia Networks. It was also announced that Rajeev Suri, the CEO of NSN would be appointed as president and CEO of Nokia Corporation, effective 1 May 2014.
On 15 April 2015, Nokia announced its intent to purchase Alcatel-Lucent for €15.6 billion in an all-stock deal. The acquisition aimed to create a stronger competitor to the rival firms Ericsson and Huawei, whom Nokia and Alcatel-Lucent had surpassed in terms of total combined revenue in 2014. The acquisition was expected to be completed in early 2016, and was subject to regulatory and shareholder approval. Regulatory approval was obtained in October 2015 and shareholder approval was announced on 4 January 2016.
On 3 November 2016, Nokia completed the acquisition of Alcatel-Lucent and it was merged into their Nokia Networks division.
On 1 August 2020, Pekka Lundmark took over the role of CEO of Nokia.
== Logos ==
== See also ==
List of networking hardware vendors
== References ==
== External links ==
Nokia Networks | Wikipedia/Nokia_Networks |
Nokia Networks (formerly Nokia Solutions and Networks (NSN) and Nokia Siemens Networks (NSN)) is a Finnish multinational data networking and telecommunications equipment company headquartered in Espoo, Finland, and wholly owned subsidiary of Nokia Corporation. It started as a joint venture between Nokia of Finland and Siemens of Germany known as Nokia Siemens Networks.
Nokia Networks has operations in around 120 countries. In 2013, Nokia acquired 100% of Nokia Networks, buying all of Siemens' shares. In April 2014, the NSN name was phased out as part of a rebranding process.
== History ==
The company was created as the result of a joint venture between Siemens Communications (minus its Enterprise business unit) and Nokia's Network Business. The formation of the company was publicly announced on 19 June 2006. Nokia Siemens Networks was officially launched at the 3GSM World Congress in Barcelona in February 2007. Nokia Siemens Networks then began full operations on 1 April 2007 and has its headquarters in Espoo, Greater Helsinki, Finland.
In January 2008 Nokia Siemens Networks acquired Israeli company Atrica, a company that builds carrier-class Ethernet transport systems for metro networks. The official release did not disclose terms, however they are thought to be in the region of $100 million. In February 2008 Nokia Siemens Networks acquired Apertio, a Bristol, UK-based mobile network customer management tools provider, for €140 million. With this acquisition Nokia Siemens Networks gained customers in the subscriber management area including Orange, T-Mobile, O2, Vodafone, and Hutchison 3G.
In 2009, according to Siemens, Siemens only retained a non-controlling financial interest in NSN, with the day-to-day operations residing with Nokia.
On 19 July 2010, Nokia Siemens Networks announced it would acquire the wireless-network equipment of Motorola. The acquisition was completed on 29 April 2011 for $975 million in cash. As of the transaction approximately 6,900 employees transferred to Nokia Siemens Networks.
On 23 November 2011, Nokia Siemens Networks announced that it would refocus its business on mobile broadband equipment, the fastest-growing segment of the market. This refocus resulted in the restructuring of the company and the planned layoffs of 17,000 employees. The plan reduced the company's work force by 23% from its 2011 level of 74,000, and helped the company trim annual operating expenses by $1.35 billion by the end of 2013.
On 12 December 2011, ADTRAN, Inc. announced it would acquire Nokia Siemens Networks fixed line Broadband Access business. This caused around 400 jobs to move to ADTRAN as part of the deal.
After the restructuring process, Nokia Siemens Networks brought in a positive turn around to its businesses. The bottom line and operating margins rose to approximately 10%, which was a significant shift from the previous sub-zero margins, with positive cash flows for six continuous quarters.
On 7 August 2013, Nokia completed the acquisition of Siemens' stake in the company and rebranded as Nokia Solutions and Networks. After this acquisition NSN became a fully owned subsidiary of Nokia.
On 29 April 2014, Nokia announced that NSN would henceforth be known as Nokia Networks. It was also announced that Rajeev Suri, the CEO of NSN would be appointed as president and CEO of Nokia Corporation, effective 1 May 2014.
On 15 April 2015, Nokia announced its intent to purchase Alcatel-Lucent for €15.6 billion in an all-stock deal. The acquisition aimed to create a stronger competitor to the rival firms Ericsson and Huawei, whom Nokia and Alcatel-Lucent had surpassed in terms of total combined revenue in 2014. The acquisition was expected to be completed in early 2016, and was subject to regulatory and shareholder approval. Regulatory approval was obtained in October 2015 and shareholder approval was announced on 4 January 2016.
On 3 November 2016, Nokia completed the acquisition of Alcatel-Lucent and it was merged into their Nokia Networks division.
On 1 August 2020, Pekka Lundmark took over the role of CEO of Nokia.
== Logos ==
== See also ==
List of networking hardware vendors
== References ==
== External links ==
Nokia Networks | Wikipedia/Nokia_Siemens_Networks |
The Application Interface Specification (AIS) is a collection of open specifications that define the application programming interfaces (APIs) for high-availability application computer software. It is developed and published by the Service Availability Forum (SA Forum) and made freely available. Besides reducing the complexity of high-availability applications and shortening development time, the specifications intended to ease the portability of applications between different middleware implementations and to admit third party developers to a field that was highly proprietary in the past.
== History ==
The AIS is part of the Service Availability Interfaces (SAI) of the SA Forum. The original specifications, released on April 14, 2003, were the Availability Management Framework (AMF), the Cluster Membership Service (CLM) and four other utility services (Checkpoint, Event, Message, Lock).
Additional services were added in subsequent releases.
Release 3 (January 18, 2006) added the first set of management services: Log, Notification and Information Model Management (IMM).
Release 4 (February 27, 2007) extended the utility services with Timer and Naming.
Release 5 (October 16, 2007) extended the management services with Security and added the Software Management Framework.
Release 6 (October 21, 2008) added the Platform Management Service to close the gap between AIS and HPI (Hardware Platform Interface).
AIS consists of 12 services and two frameworks. The services are classified into three functional groups - AIS Platform Services, basic AIS Management Services, and general AIS Utility Services - in addition to the AIS Frameworks.
Initially, the APIs were defined in the C programming language only, but as of July 2008, the Java mapping of the different service APIs is being released incrementally.
== Service dependencies ==
The different services and frameworks of the interface specifications have been designed to be modular and, to a certain degree, independent of one another. This allows a system providing only AIS and no HPI to exist and vice versa.
The only required architectural dependency is the dependence on the Cluster Membership Service (CLM). All AIS Services, with the exception of the Platform Management Service (PLM) and the Timer Service (TMR), depend on CLM.
It is expected that all AIS Services should use the AIS Management Services to expose their administrative interfaces, configuration, and runtime management information (fig2).
== Platform services ==
The Platform Management Service (PLM) provides a logical view of the hardware and the low-level software of the system. Low-level software in this sense comprises the operating system and virtualization layers that provide execution environments for all kinds of software.
The main logical entities implemented by PLM are :
Hardware Element (HE) - A hardware element is a logical entity that represents any kind of hardware entity, which can be, for instance, a chassis, a CPU blade, or an I/O device. Typically, all Field Replaceable Units (FRUs) are modeled as hardware elements.
Execution Environment (EE) - An execution environment is a logical entity that represents an environment capable of running some software programs. For example, a CPU blade or an SMP machine runs a single operating system instance modeled as an execution environment. Different virtualization architectures are supported (fig 4).
PLM maintains the state of these entities in the information model and provides means to control them and track any state changes. To fulfill these tasks for HEs, the PLM Service typically uses HPI. In case of EEs, PLM is in charge of retrieving all necessary information about the health of the operating system and any available virtualization layer.
The Cluster Membership Service (CLM) provides applications with membership information about the nodes that have been administratively configured in the cluster configuration (these nodes are also called cluster nodes or configured nodes) and is core to any clustered system. A cluster consists of this set of configured nodes, each with a unique node name.
The two logical entities implemented by the Cluster Membership Service are:
Cluster - Represents the cluster itself and it is the parent object of the cluster node objects.
Cluster Node - Represents a configured cluster node.
The CLM provides APIs to retrieve the current cluster membership information and to track membership changes (e.g. node leave, node join). All cluster-wide AIS services must use the CLM track API to determine the membership.
== Management services ==
The various entities implemented by the AIS services (e.g. execution environments, checkpoints, components, etc.) are represented as managed objects in the SA Forum Information Model (IM), which can be seen as a configuration management database. The managed objects are instances of object classes defined by the relevant AIS service specification, which defines the class attributes and administrative operations. The administrative operations specified for the object classes represent operations that can be performed on the entities represented by the objects, e.g. locking a service unit or exporting the contents of the IM in XML format. The objects in the IM are stored in a tree hierarchy where an object can have, at most, one parent object and any number of child objects.
The logical entities represented by the objects in the IM are not generally implemented by the IMM Service itself; instead, user applications and the AIS Services, such as the Checkpoint Service or the Availability Management Framework provide their implementation. Therefore, these are called object implementers (OI). For management purposes, all AIS services expose their implemented entities as managed objects through the IMM service.
There are two categories of objects and attributes in the IM: runtime and configuration.
Runtime objects and attributes reflect the current state of the entities they represent – they are of descriptive nature.
In contrast, configuration objects and attributes are prescriptive as for management applications – or object managers (OM) – they are the means to provide input to the object implementers on what entities they need to implement.
Configuration objects may include both configuration and runtime attributes while runtime objects may include only runtime attributes. Administrative operations may be defined on both object categories.
Accordingly, the IMM Service exposes a “southbound” interface – the IMM-OI API – to object implementers and a “northbound” interface – the IMM-OM API – to management applications (fig. 5), e.g. SNMP agents, and mediates between these two parties. It is also responsible for storing the persistent objects and attributes.
=== Log ===
The log service is intended for event logging, that is, for collecting cluster-wide, function-based (as opposed to implementation specific) information about the system, which is suited for system administrators or automated tools.
The Log Service enables applications to express and write log records through log streams that lead to particular output destinations, such as a named file. Once at the output destination, a log record is subject to output formatting rules, which are configurable and public. The logging application does not need to be aware of any of these aspects (e.g. the destination file location, file rotation or formatting, etc.) as the Log Service handles them based on the current settings for the targeted log stream. Since the output format is public, third party tools can read these log files.
Four types of log streams are specified: alarm (ITU X.733 and ITU X.736 based log records), notification (ITU X.730 and ITU X.731 based log records), system and application. The application type is used by applications to define application-specific log streams. There is exactly one predefined log stream for each of the alarm, notification, and system log stream types in an SA Forum cluster. User applications are allowed to use any of the predefined streams or create new application-specific log streams.
=== Notification ===
The notification service is - to a great degree - based on the ITU-T Fault Management model (as found in the X.700 series of documents) as well as on many other supportive recommendations.
The notification service is centered on the concept of a notification, which explains an incident or change in status. The term ‘notification’ is used instead of ‘event’ to clearly distinguish it from ‘event’ as defined by the AIS Event Service.
The NTF service is based on the publish-subscribe paradigm. It defines six notification types: alarm, security alarm, object creation/deletion, state change, attribute value change, and miscellaneous. Notifications are generated/published by producers using the notification producer API. The notification consumers can be either subscribers, who subscribe for notifications and receive them as they occur; or readers, who retrieve notifications from persisted logs using the notification consumer API. Both types of notification consumers may define filters which specify characteristics of the notifications they are interested in receiving or reading.
Notifications may be generated by AIS Services as well as by applications. AIS Services that generate notifications have a section in the specification that describes their notifications.
=== Security ===
The security service provides mechanisms that can be used by AIS Services to authenticate AIS Service (and potentially other) client processes within the cluster and to authorize them to perform particular activities. These mechanisms can be used to preserve the integrity of the high-availability infrastructure and of SA Forum applications, including their data, by protecting against unauthorized access.
The enforcement of security is delegated to the AIS Service implementations themselves: Security-enabled AIS Services request authorization from the SEC implementation on behalf of their client processes as they initiate different activities. SEC responds to these authorization requests with a granted or denied indication, and it is up to the AIS Service to allow or disallow the operation accordingly. SEC provides these indications based on the set of security policies configured via IMM. It also informs its subscribers about policy changes using appropriate callbacks.
== Frameworks ==
=== Availability Management Framework ===
The Availability Management Framework is the enabler of service availability in SA Forum compliant systems. It coordinates the workload of the different entities under its control depending on their state of readiness to provide services. For this purpose, the application needs to be described according to the information model specified for AMF. This model describes which resources belong to the application, within the cluster, and which services the application provides.
The basic logical entity of this information model is the component, which represents a set of resources to the Availability Management Framework that encapsulate some specific application functionality. The workload generated by provisioning some service that can be assigned to a component by AMF is represented as a component service instance (CSI). When the component is actively providing the service, it is assigned the active state on behalf of the CSI representing the service.
The fundamental principle of fault tolerant design is to provide the services by a set of redundant entities and therefore components need to be able to act as a standby on behalf of the CSI. The standby components maintain themselves in a state so that they are capable of taking over the service provisioning, should the component with the active assignment fail. The role of AMF is to assign active or standby workloads to the components of an application as a function of component state and system configuration.
Accordingly, the APIs provided by the Availability Management Framework enable component registration, life cycle management and workload assignments. They include functions for error reporting and health monitoring. They also allow tracking the assignment of component service instances among the set of components protecting the CSI.
The Availability Management Framework configuration includes recovery and repair policies. It allows the prioritization of resources and provides for a variety of redundancy models. These range from the simple 2N model (also known as 1+1, or active-standby) to more sophisticated ones such as the N-way redundancy model, which allows for more than one standby assignment on behalf of the same component service instance or the N-way-active that allows multiple active assignments.
To simplify the administration, AMF further groups components into service units and service groups, and component service instances into service instances. All of these compose an application. Via IMM, a set of administrative operations are available on these logical entities.
For software management purposes, the entities running the same software are grouped into types, which allows for a single point entry for the configuration of these entities.
=== Software Management Framework ===
An SA Forum compliant system can be characterized by its deployment configuration, which consists of the software deployed in the system along with all configured software entities. The deployment configuration constitutes an essential part of the information model managed by the IMM Service.
The Software Management Framework (SMF) maintains the part of the information model that describes the software available for, and deployed in, the cluster. But the main purpose of SMF is enabling the evolution of a live system by orchestrating the migration from one deployment configuration to another. In SMF terms, this migration process is called an upgrade campaign.
The Software Management Framework defines an XML schema to be used to specify an upgrade campaign. An SMF implementation migrates the system from one deployment configuration to a new desired one based on such an XML file, which is essentially a script of ordered actions and configuration changes that lead to the new configuration.
During this migration, SMF
maintains the campaign state model,
monitors for potential error situations caused by the migration, and
deploys error recovery procedures as required.
To accomplish all these tasks, the SMF implementation interacts at least (1) with AMF in order to maintain availability, (2) with IMM to carry out changes to the information model, and (3) with NTF to receive notifications that may indicate error situations caused by the ongoing campaign.
The Software Management Framework also provides an API for client processes to register their interest in receiving callbacks when a relevant upgrade campaign is initiated in the cluster and as it progresses through significant milestones. This allows for coordination of application-specific actions with the upgrade. This may range from simply blocking the initiation of an upgrade campaign when the application performs some critical task to coordinating application-level upgrade action, such as upgrading the database schema or deploying new protocols.
For software vendors delivering applications to be deployed in a SA Forum cluster, the Software Management Framework also defines an XML schema for the entity types file, which describes the software entity types implemented by the application. This information is used to come up with appropriate deployment configurations.
== Utility Services ==
=== Checkpoint ===
The Checkpoint Service provides a facility for processes to record checkpoint data incrementally, which can be used to protect an application against failures. When a process recovers from a failure (with a restart or a failover procedure), the Checkpoint Service can be used to retrieve the previously checkpointed data and resume execution from the recorded state, thus minimizing the impact of the failure.
Checkpoints are cluster-wide entities. A copy of the data stored in a checkpoint is called a checkpoint replica, which is typically stored in main memory rather than on disk for performance reasons. A checkpoint may have several checkpoint replicas stored on different nodes in the cluster to protect it against node failures. The process creating the checkpoint may choose between synchronous and asynchronous replica-update policies. In case of asynchronous replication, co-location can also be selected to optimize update performance.
=== Events ===
The Event Service is a publish/subscribe multipoint-to-multipoint communication mechanism that is based on the concept of event channels: one or more publishers communicate asynchronously with one or more anonymous subscribers by using events over an event channel. Event channels are cluster-wide named entities that provide best effort delivery of events. Publishers can also be subscribers on the same event channel.
Events consist of a standard header and zero or more bytes of published event data. The Event Service API does not impose a specific layout for the published event data.
When a process subscribes on an event channel to receive published events, it specifies the filters to apply on the published events. Events are only delivered to the process if they satisfy the provided filters.
=== Locks ===
The Lock Service is a distributed lock service, which is intended for use in a cluster where processes in different nodes might compete with each other for access to a shared resource. For them, the Lock Service provides entities called lock resources, which in turn, application processes use to coordinate access to those shared resources.
The Lock Service provides a simple lock model supporting one locking mode for exclusive access and another one for shared access. The locks provided by the Lock Service are non-recursive. Thus, claiming one lock does not implicitly claim another lock; rather, each lock must be claimed individually.
=== Messages ===
The Message Service specifies APIs for a cluster-wide inter-process communicationsystem. The communication is based on message queues identified by a logical name. Any number of processes can send messages to a message queue, but one process at a time at most can open it for receiving. The single message queue thus supports point-to-point or multi-point-to-point communication patterns.
Processes sending messages to a message queue are unaware of the identity of the receiving process; therefore, the process that was originally receiving these messages may have been replaced by another process during a failover or switch-over.
Message queues can be grouped together to form message queue groups. Message queue groups permit multipoint-to-multipoint communication. They are identified by logical names so that a sender process is unaware of the number of message queues and of the location of the message queues within the cluster with which it is communicating. The message queue groups can be used to distribute messages among message queues pertaining to the message queue group. MSG defines three unicast distribution policies – equal load distribution, local equal load distribution and local best queue – and the broadcast (multicast) policy.
On request, the Message Service provides different delivery guarantees (e.g. acknowledgement, message persistency, etc.) on message queues and on unicast message queue groups.
=== Naming ===
The Naming Service provides a mechanism by which human-friendly names are associated with (‘bound to’) objects, so that these objects can be looked up given their names. The objects typically represent service access points, communication end-points and other resources that provide some sort of service.
The Naming Service imposes neither a specific layout nor a convention on either the names (UTF-8 encoding assumed) or the objects to which they are bound. It allows the users of the service to select and use their own naming schema without assuming any specific hardware or logical software configuration. The clients of the Naming Service are expected to understand the structure, layout, and semantics of the object bindings they intend to store inside and retrieve from the service.
=== Timers ===
The Timer Service provides a mechanism by which client processes can set timers and be notified when a timer expires. A timer is a logical object that is dynamically created and represents its expiry time as either an absolute time or duration from the current time.
The Timer Service provides two types of timers: single event timers and periodic timers. Single event timers will expire once and are deleted after notification. Periodic timers will expire each time a specified duration is reached, and the process is notified about the expirations. Periodic timers have to be explicitly deleted by invoking a timer deletion function.
=== Programming model ===
All the AIS services share the same programming model. The same naming conventions, standard predefined types and constants, API semantics, library life cycle control, etc. are used throughout the specification.
The SA Forum Application Interface occurs between a process and a library that implements the interface. The interface is designed for use by both multithreaded and single-threaded application processes. The term 'process' can be regarded as being equivalent to a process defined by the POSIX standard; however, AIS does not mandate a POSIX process, but rather, any equivalent entity that a system provides to manage executing software.
The area server is an abstraction that represents the server that provides services for a specification area (Availability Management Framework, Cluster Membership Service, Checkpoint Service, and so on). Each area has a separate logical area server, although the implementer is free to create a separate physical module for each area server or combine one or more area servers into a single physical module.
The area implementation libraries may be implemented in one or several physical libraries; however, a process is required to initialize, register, and obtain an operating system selection object separately for each area's implementation library. Thus, from a programming standpoint, it is useful to view these as separate libraries.
The usage model is typical of an event-driven architecture, in which the application performs a setup and then receives callbacks as events occur (fig 6).
The use of a Service Availability library starts with a call to initialize the library, which potentially loads any dynamic code and binds the asynchronous calls implemented by the process. When the process no longer requires the use of the area functions, it calls the area finalization function, which disassociates the process from the interface area implementation instance and recovers any associated resources.
AIS employs both the synchronous and asynchronous programming models. Synchronous APIs are generally used for library and association housekeeping interfaces. Many AIS Services provide the capability of tracking changes in the entities that they implement. The API track typically consists of three functions: the client-invoked initiate and stop tracking of an entity; and the service-invoked callback to notify the client about (pending) changes of a tracked entity.
== Backward compatibility ==
To achieve backward compatibility when evolving the AIS specification, it follows a number of rules:
A function or type definition never changes for a specific SA Forum release.
Changes in a function or type definition (adding a new argument to a function, adding a new field to a data structure) force the definition of a new function or type name. A new function or type name is built from the original name in the previous version with a suffix indicating the version where the function/type changed (for instance, saAmfComponentRegister_3()).
As an exception to the previous rule, new enum values, flag values, or union fields can be added to an existing enum, flag, or union type without changing the type name, as long as the size of the enum, flag, or union type does not change.
AIS implementers must ensure that they respect the version numbers provided by the application when it initializes the library and do not expose new enum values to applications using older versions.
AIS implementers must also ensure that they respect the version numbers provided by the application when the library is initialized, with regard to new or modified error codes and do not expose error codes that only apply to functions in the most recent version of the specification to applications written to an older version of the specification.
As an example, consider a majorVersion Vx of a given service that includes a function f(), and assume that f() had to be modified in a newer majorVersion Vy (Vy > Vx), which led to the introduction of the f_y() variant that now replaces f() in Vy.
Considering an AIS implementation that supports both versions Vx and Vy, a process can initialize the library specifying either Vx or Vy:
if the process initializes a library handle with Vx, this handle does not provide access to functions that have been introduced in versions newer than Vx. In particular, this handle will not enable the process to successfully invoke f_y()
if the process initializes a library handle with Vy, this handle does not provide access to a function introduced in versions older than Vy and then replaced by a newer variant of the same function. In particular, this handle will not enable the process to successfully invoke f().
Note, however, that a process may initialize the library multiple times each time with the version appropriate to the functionality it intends to obtain.
The specification document of an AIS Service for Vy only includes the latest variant of a function or type definition supported by Vy.
Specification releases are versioned as: <release code>.<major version>.<minor version>
The release code is a capital letter. Backward compatibility is maintained only among versions of the same release code. The major version and minor version are incremental numbers. Releases with major number change may introduce new features and change the API in a backward-compatible way as described above. Releases with a minor number change do not change the API. They provide bug fixes, editorial changes and clarification to their predecessor.
== Implementation Registry ==
The SA Forum Implementation Registry is a process that enables implementations of the SA Forum specifications to be registered and made publicly available. Membership is not required to register implementations. Implementations that have been successfully registered may be referred to as “Service Availability Forum Registered”.
== See also ==
Service Availability Forum
OpenSAF
== References ==
== External links ==
Specification tutorials
SA Forum web site
OpenAIS
OpenSAF | Wikipedia/Application_Interface_Specification |
In telecommunications, data signaling rate (DSR), also known as gross bit rate, is the aggregate rate at which data passes a point in the transmission path of a data transmission system.
== Properties ==
The DSR is usually expressed in bits per second.
The data signaling rate is given by
∑
i
=
1
m
log
2
n
i
T
i
{\displaystyle \sum _{i=1}^{m}{\frac {\log _{2}{n_{i}}}{T_{i}}}}
where m is the number of parallel channels, ni is the number of significant conditions of the modulation in the i-th channel, and Ti is the unit interval, expressed in seconds, for the i-th channel.
For serial transmission in a single channel, the DSR reduces to (1/T)log2n; with a two-condition modulation, i. e. n = 2, the DSR is 1/T, according to Hartley's law.
For parallel transmission with equal unit intervals and equal numbers of significant conditions on each channel, the DSR is (m/T)log2n; in the case of a two-condition modulation, this reduces to m/T.
The DSR may be expressed in bauds, in which case, the factor log2ni in the above summation formula should be deleted when calculating bauds.
In synchronous binary signaling, the DSR in bits per second may be numerically the same as the modulation rate expressed in bauds. Signal processors, such as four-phase modems, cannot change the DSR, but the modulation rate depends on the line modulation scheme, in accordance with Note 4. For example, in a 2400 bit/s 4-phase sending modem, the signaling rate is 2400 bit/s on the serial input side, but the modulation rate is only 1200 bauds on the 4-phase output side.
== Maximum rate ==
The maximum user signaling rate, synonymous to gross bit rate or data signaling rate, is the maximum rate, in bits per second, at which binary information can be transferred in a given direction between users over the communications system facilities dedicated to a particular information transfer transaction, under conditions of continuous transmission and no overhead information.
For a single channel, the signaling rate is given by
S
C
S
R
=
log
2
n
T
{\displaystyle SCSR={\frac {\log _{2}{n}}{T}}}
, where SCSR is the single-channel signaling rate in bits per second, T is the minimum time interval in seconds for which each level must be maintained, and n is the number of significant conditions of modulation of the channel.
In the case where an individual end-to-end telecommunications service is provided by parallel channels, the parallel-channel signaling rate is given by
P
C
S
R
=
∑
i
=
1
m
log
2
n
i
T
i
{\displaystyle PCSR=\sum _{i=1}^{m}{\frac {\log _{2}{n_{i}}}{T_{i}}}}
, where PCSR is the total signaling rate for m channels, m is the number of parallel channels, Ti is the minimum interval between significant instants for the I-th channel, and ni is the number of significant conditions of modulation for the I-th channel.
In the case where an end-to-end telecommunications service is provided by tandem channels, the end-to-end signaling rate is the lowest signaling rate among the component channels.
== Rates and standards ==
== See also ==
Bit rate
Bandwidth (computing)
Baud
Symbol rate
== References ==
This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22. | Wikipedia/Data_signaling_rate |
A model figure is a scale model representing a human, monster or other creature. Human figures may be either a generic figure of a type (such as "World War II Luftwaffe pilot"), a historical personage (such as "King Henry VIII"), or a fictional character (such as "Conan").
Model figures are sold both as kits for enthusiast to construct and paint and as pre-built, pre-painted collectable figurines. Model kits may be made in plastic (usually polystyrene), polyurethane resin, or metal (including white metal); collectables are usually made of plastic, porcelain, or (rarely) bronze.
There are larger size (12-inch or 30 cm tall) that have been produced for recent movie characters (Princess Leia from Star Wars, for example). Large plastic military figures are made by some model soldier manufacturers as a sideline.
== Military models ==
Enthusiasts may pursue figure modeling in its own right or as an adjunct to military modeling.
There is also overlap with miniature figures (minis) used in wargames and role-playing games: minis are usually less than 54 mm scale, and do not necessarily represent any given personage.
Back in the early '80s and '90s military modeling figures were largely produced in 1:72 and 1:35 scales with other scales such as 1:48 and 1:32 holding a smaller market share. Typically 1:48 scale was reserved for aircraft and aircraft support vehicles with figures being maintenance and flight crews while 1:32 scale miniatures were composed largely of vehicles such as tanks and their crews.
1:35 scale miniatures were produced by many companies such as Tamiya, Testor's, Revell, Monogram and others. Kits of soldiers, vehicles and combinations covered World War I through Vietnam with the largest portion centering on World War II. 1/72 scale miniatures covered a much wider and diverse range of time periods with Atlantic offering figures of Ancient Egyptians, Greeks, Romans, Cowboys, American Indians and many more. Other company's such as Airfix supplied not only high-quality figures in 1:72 scale but also fine planes and military vehicles and still do so today. One of the largest distinctions between 1:72 scale and 1:35 scale aside from the obvious size was the amount of ready-to-paint dioramas and sets available to small-scale modelers. Airfix, a leader in the small-scale model market offered several kits for modelers from pontoon bridges, the Atlantic wall, Waterloo, and many others. These kits came with everything a hobbyist would need to portray a given moment from buildings and trees to vehicles and men. None of these were available to the larger scale modeler.
Tamiya, a higher-end supplier of military vehicle and soldier kits, has, in the past few years, taken 1:48 scale modeling a step further offering an interesting line of German and American World War II figures and vehicles making it possible to incorporate tanks, jeeps, and foot soldiers into dioramas with aircraft, something which was only possible in 1:72 scale for quite a long time. For the serious military modeler this opens a new realm of possibilities in diorama making.
The same growth in availability is true for 1:32 scale as well. For quite a while 1:32 scale figures were more or less better versions of the army men children play with. Kits came as single-cast figures molded as a unit instead of the ready-to-assemble versions found at 1:48 and 1:35 scale where arms, helmets and gear must be cut from plastic sprues and glued together. 1:32 scale soldiers were often slightly lower quality than their 1:35 scale counterparts as they were molded from a softer plastic allowing things like rifle barrels to bend while the soldiers sat in the boxes. 1:32 scale kits were limited and this made extensive modeling difficult. Lately, 1:32 scale modeling has made a large push to expand as companies now sell these figures professionally pre-painted making them exceptional for large-scale military gaming of all sorts. In fact, the diorama industry has started supplying pre-painted diorama scenery as well making high-quality 1:32 scale diorama making much easier than ever before.
Figure model kits can be as large as 1:16 scale. These kits include motorized vehicles and stand alone figures. Kits of this size take a great deal of effort and time to paint as lengths must be taken to get the details of the paint job precise whereas with smaller kits, while details is still essential, there is less to be done.
Many model figures used for gaming are measured in millimeters ranging from 15 to 80 mm with miniature wargaming figures running on the smaller end especially where armored vehicles are used. Traditional modelers tend to stick to the more common 1:72-1:32 scales leaving the other sizes to the gamers.
As with all things, quality and price vary from manufacturer to manufacturer and the result of a model is often limited by its initial quality. Today many new model manufacturers take great lengths to make 1:72, 1:48, 1:35 and 1:32 scale models as highly detailed and realistic as possible. This, unfortunately, makes many of the older, still existing sets, less desirable for diorama making but still fun to build, especially as starter kits for a less experienced modeller. Many of these older kits can still be found online at a reasonable price and while they don't offer as many pieces or as highly detailed molding, they can still produce a respectable product after paint and proper weathering is administered.
Model aircraft and vehicle kits in even smaller scales will also often include "model figures," or can be purchased as accessories. There are also kits of the drivers and servicers of cars, and the series of figurines that stand in the streets and platforms of model railroads.
== Japanese figures ==
Model figures based on icons like Hello Kitty, as well as characters appearing in anime, manga, kaiju (monster) series, science fiction/fantasy films and video games, is a major part of otaku fandom. It's also a large part of the global animation merchandising market from Japan which is estimated to be worth around 663 billions Japanese yen. Some hobbyists concentrate specifically on a certain type of figure, such as garage kits, gashapon (capsule toys), or PVC bishōjo (pretty girl) statues. Such figures prominently featured in work of modern artist Takashi Murakami. Through his company Kaikai Kiki, he has produced a number of limited designer toys to be sold in otaku oriented stores.
While many different companies manufacture and sell anime figures, prices for the same figure have large differences depending on the authenticity and quality of the figure. Authentic figures are normally figures of characters that are licensed by the creators, thus leading to significantly higher prices. Some of the most well known manufacturers for their consistency and quality are such as Good Smile Company, Aniplex, Hot Toys, Bandai and others. Figures are usually classified as prize figures, scale figures and others, with prize figures being lower cost options often used in Claw crane games, while scale figures can cost several hundreds to thousands USD.
=== Noodle stopper ===
A noodle stopper is a type of figurine based on manga, anime, or even video game characters which is ostensibly meant to secure by gravity the lid for ramen containers such that they do not boil over. Due to their ornate designs, they are often displayed as ordinary figurines. (Stopper is a misnomer, as they are not inserted into the container.)
== Garage kits ==
Garage kit figures are produced by both amateurs and professionals, and usually cast out of polyurethane resin. In Japan they often portray anime characters and in the US they are often movie monsters. Garage kits are usually produced in limited numbers and are more expensive than typical injection molded plastic figures and kits.
== US history ==
In the 50s and 60s plastic model kits such as cars, planes or space ships became common in the US. There were also cheap plastic models for the popular market of movie monsters, comic book heroes, and movie and television characters in 1:8 size (about 9 inches or 23 cm in height). These included monsters like Frankenstein, The Wolf Man, Dracula, and the Creature from the Black Lagoon. One of the largest producers of monster figures were the Aurora Plastics Corporation, who produced many thousands figures from each mould. This market disappeared and no firm since has produced anything to match their quantities. Instead smaller (3¾-inch or 10 cm) action figures of have taken over the popular market.
In the 1970s, Aurora's figure molds had been sold to Monogram and by the mid-to late 1970s, the models had been discontinued and were difficult to find in hobby stores.
In the mid-1980s some who were kids in the 1950s and 60s resumed their interest in the old Aurora monster models. An underground market developed through which enthusiasts could acquire the original plastic model kits. While the prices in the 50s and 60s had been only a few dollars, now the kits were selling for as much as $125 for some of the rarer monster models.
In the early to mid-1980s, hobbyists began creating their own garage kits of movie monsters, often without permission from copyright holders. They were usually produced in limited numbers and sold primarily by mail order and at toy and hobby conventions.
In the mid- to late 1980s, two model kit companies moved the monster model kit hobby toward the mainstream. Horizon Models in California and Screamin' Models in New York began licensing vinyl model kits of movie monsters. Horizon focused primarily on classic horror film characters (like Bride of Frankenstein, Invisible Man, The Phantom of the Opera) and comic book characters (like Captain America and Iron Man). Screamin' focused primarily on characters from more contemporary slasher movies like A Nightmare on Elm Street, Hellraiser and franchises like Star Wars and Mars Attacks. Hobby stores began to carry these products in limited supply.
By the 1990s model kits were produced in the US, UK as well as Japan and distributed through hobby and comic stores. Large hobby companies like AMT-Ertl and Revell/Monogram (the same Monogram that bought the Aurora monster molds) began marketing vinyl model kits of movie monsters, the classic Star Trek characters, and characters from one of the Batman films. There was an unprecedented variety of licensed models figure kits.
In the late 1990s model kit sales went down. Hobby and comic stores and their distributors began carrying fewer garage kits or closed down. Producers like Horizon and Screamin' shut their doors.
As of 2009, there are two American garage kit magazines, Kitbuilders Magazine and Amazing Figure Modeler, and there are garage kit conventions held each year, like WonderFest USA in Louisville, Kentucky.
== Model figure collecting ==
Model figure collectors, like most hobby collectors, usually have a specific criterion for what they collect, such as Civil-War soldiers, or Warhammer gaming figures.
Specifically with an eye to collectors, manufacturers of collectable model figures make chase figures. This is a model figure that is released in limited amounts relative to the rest of an assortment, often something like "one chase figure for every two cases of regular product" or similar. This is comparable to the chase cards in the collectible card game industry. The name comes from the assumption that collectors, in their need to "collect them all" will put in more effort than usual to "chase" down these figures.
Generally speaking, chase figures are rare in toy lines aimed at youth markets, although there are occasionally shortpacked figures (shipped in lower numbers than other figures in its release cycle). Chase figures are more common in collector-oriented lines like Marvel Legends and WWE Classics.
== See also ==
Action figure
Animal figurine
Sport figurine
Toy soldier
== References == | Wikipedia/Model_figure |
A raised-relief map, terrain model or embossed map is a three-dimensional representation, usually of terrain, materialized as a physical artifact. When representing terrain, the vertical dimension is usually exaggerated by a factor between five and ten; this facilitates the visual recognition of terrain features.
== History ==
If the account of Sima Qian (c. 145–86 BCE) in his Records of the Grand Historian is proven correct upon the unearthing of Qin Shi Huang's tomb, the raised-relief map has existed since the Qin dynasty (221–206 BCE) of China. Joseph Needham suggests that certain pottery vessels of the Han dynasty (202 BCE – 220 CE) showing artificial mountains as lid decorations may have influenced the raised-relief map.
The Han dynasty general Ma Yuan made a raised-relief map of valleys and mountains in a rice-constructed model of 32 CE. Such rice models were expounded on by the Tang dynasty (618–907) author Jiang Fang in his Essay on the Art of Constructing Mountains with Rice (c. 845). A raised-relief map made of wood representing all the provinces of the empire and put together like a giant 0.93 m2 (10 ft2) jigsaw puzzle was invented by Xie Zhuang (421–466) during the Liu Song dynasty (420–479).
Shen Kuo (1031-1095) created a raised-relief map using sawdust, wood, beeswax, and wheat paste. His wooden model pleased Emperor Shenzong of Song, who later ordered that all the prefects administering the frontier regions should prepare similar wooden maps which could be sent to the capital and stored in an archive.
In 1130, Huang Shang made a wooden raised-relief map which later caught the attention of the Neo-Confucian philosopher Zhu Xi, who tried to acquire it but instead made his own map out of sticky clay and wood. The map, made of eight pieces of wood connected by hinges, could be folded up and carried around by one person.
Later, Ibn Battuta (1304–1377) described a raised-relief map while visiting Gibraltar.
In his 1665 paper for the Philosophical Transactions of the Royal Society, John Evelyn (1620–1706) believed that wax models imitating nature and bas relief maps were something entirely new from France. Some later scholars attributed the first raised-relief map to one Paul Dox, who represented the area of Kufstein in his raised-relief map of 1510.
== Construction ==
There are a number of ways to create a raised-relief map. Each method has advantages and disadvantages in regards to accuracy, price, and relative ease of creation.
=== Layer Stacking ===
Starting with a topographic map, one can cut out successive layers from some sheet material, with edges following the contour lines on the map. These may be assembled in a stack to obtain a rough approximation of the terrain. This method is commonly used as the base for architectural models, and is usually done without vertical exaggeration. For models of landforms, the stack can then be smoothed by filling with some material. This model may be used directly, or for greater durability a mold may be made from it. This mold may then be used to produce a plaster model.
=== Vacuum Formed Plastic Maps ===
A combination of computer numerical control (CNC) machining a master model, and vacuum forming copies from this, can be been used to rapidly mass-produce raised-relief maps. The Vacuum Forming technique, invented in 1947 by the Army Map Service in Washington, D.C., uses vacuum-formed plastic sheets and heat to increase the production rate of these maps. To make the Vacuum-Formed plastic maps, first a master model made of resin or other materials is created with a computer guided milling machine using a digital terrain model. Then a reproduction mold is cast using the master mold and a heat and pressure resistant material. Fine holes are put into the reproduction mold so that the air can later be removed by a vacuum. Next, a plastic sheet is applied to the mold so that they are airtight, and a heater is placed above the plastic for about 10 seconds. The vacuum is then applied to remove the remaining air. After letting the plastic cool, it can be removed and the terrain is complete. After this step, a color map can be overlaid/printed onto the bases that were created to make it realistic.
Vacuum-formed plastic maps have many advantages and disadvantages. They can be quickly produced, which can be beneficial in time of war or disaster. However, the accuracy of certain points throughout the model can vary. The points that touch the mold first are the most accurate, while the points that touch the mold last can become bulged and slightly distorted. Also, the effectiveness of this particular construction method varies by the terrain being represented. They are not good at representing sharp-edged land forms like high mountain ranges or urban areas.
=== 3D Printing ===
Another method which is becoming more widespread is the use of 3D printing. With the rapid development of this technology its use is becoming increasingly economic. In order to create a raised-relief map using a 3D printer, Digital Elevation Models (DEM) are rendered into a 3D computer model, which can then be sent to a 3D printer. Most consumer-level 3D printers extrude plastic layer by layer to create a 3D object. However, if a map is needed for commercial and professional uses, higher-end printers can be used. These 3D printers use a combination of powders, resins, and even metals to create higher-quality models. After the model is created, color can be added to show different land cover characteristics, providing a more realistic view of the area. Some benefits of using a 3D printed model include the technology and DEMs being more prevalent easier to find, and that they are easier to understand than a typical topographic map.
=== DEM/TIN Formed Papercraft Maps ===
Creating a papercraft raised relief map via a Digital Elevation Model (DEM) is a low cost alternative to many other methods. The method involves converting the DEM to a triangulated irregular network (TIN), unfolding the TIN, printing the unfolded TIN on paper, and assembling the printout into a physical 3D model. This method allows raised relief maps to be constructed without the need for specialized equipment or extensive training. The degree of realism and accuracy of the resulting maps is similar to that of layer stacking models. However, the quality of the final map heavily depends on the characteristics of the TIN used.
== Non-terrain applications ==
For appropriate mathematical functions and especially for certain types of statistics displays, a similar model may be constructed as an aid to understanding a function or as an aid to studying the statistical data.
== Notable examples ==
The Great Polish Map of Scotland is claimed to be the largest terrain relief model, constructed out of brick and concrete in the grounds of a hotel near Peebles, Scotland. It measures 50 by 40 metres (160 ft × 130 ft).
The Relief map of Guatemala, in Guatemala City, is of similar size as the Great Polish Map of Scotland. It was built in 1904–05.
However, a site in Ningxia province, China at 38°15′57″N 105°57′4″E was spotted in 2006 using satellite imagery. It measured 900 by 700 metres (3,000 ft × 2,300 ft), had a 3-kilometre (1.9 mi) perimeter and appeared to be a large scale relief model (1:500) of Aksai Chin, a disputed territory between China and India.
== See also ==
Digital elevation model
Digital terrain model
Hypsometric tints
List of Chinese inventions#R
Musée des Plans-Reliefs
Participatory 3D modelling (P3DM)
Triangulated irregular network
Karl Wenschow (German Wikipedia)
== References ==
== Further reading ==
de Crespigny, Rafe. (2007). A Biographical Dictionary of Later Han to the Three Kingdoms (23–220 AD). Leiden: Koninklijke Brill. ISBN 90-04-15605-4.
Ebrey, Patricia Buckley, Anne Walthall, James B. Palais (2006). East Asia: A Cultural, Social, and Political History. Boston: Houghton Mifflin Company. ISBN 0-618-13384-4.
Needham, Joseph. (1986). Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth. Taipei: Caves Books, Ltd.
Sivin, Nathan (1995). Science in Ancient China: Researches and Reflections. Brookfield, Vermont: VARIORUM, Ashgate Publishing.
== External links ==
Terrain Models, a website of the Institute of Cartography at ETH Zurich
Library of Congress: Geography and Maps - Globes and Terrain Models
Report of the Relief Map Department, G-2-C, G.H.Q., of the American Expeditionary Forces
Allan McCollum: The Topographical Model Donation Project
How to build a landscape-model by Konrad Weber
Participatory Avenues a web site dedicated to the participatory manufacture of raised relief models in the context of participatory planning, development and advocacy
Adding the Third Dimension, an article (PDF 744KB) that describes ways of creating maps that "effectively present the third dimension." | Wikipedia/Terrain_model |
Railway modelling (UK, Australia, New Zealand, and Ireland) or model railroading (US and Canada) is a hobby in which rail transport systems are modelled at a reduced scale.
The scale models include locomotives, rolling stock, streetcars, tracks, signalling, cranes, and landscapes including: countryside, roads, bridges, buildings, vehicles, harbors, urban landscape, model figures, lights, and features such as rivers, hills, tunnels, and canyons.
The earliest model railways were the 'carpet railways' in the 1840s. The first documented model railway was the Railway of the Prince Imperial (French: Chemin de fer du Prince Impérial) built in 1859 by Emperor Napoleon III for his then 3-year-old son, also Napoleon, in the grounds of the Château de Saint-Cloud in Paris. It was powered by clockwork and ran in a figure-of-eight. Electric trains appeared around the start of the 20th century, but these were crude likenesses. Model trains today are more realistic, in addition to being much more technologically advanced. Today modellers create model railway layouts, often recreating real locations and periods throughout history.
The world's oldest working model railway is a model designed to train signalmen on the Lancashire and Yorkshire Railway. It is located in the National Railway Museum, York, England and dates back to 1912. It remained in use until 1995. The model was built as a training exercise by apprentices of the company's Horwich Works and supplied with rolling stock by Bassett-Lowke.
== General description ==
Involvement ranges from possession of a train set to spending hours and large sums of money on a large and exacting model of a railroad and the scenery through which it passes, called a "layout". Hobbyists, called "railway modellers" or "model railroaders", may maintain models large enough to ride (see Live steam, Ridable miniature railway and Backyard railroad).
Modellers may collect model trains, building a landscape for the trains to pass through. They may also operate their own railroad in miniature. For some modellers, the goal of building a layout is to eventually run it as if it were a real railroad (if the layout is based on the fancy of the builder) or as the real railroad did (if the layout is based on a prototype). If modellers choose to model a prototype, they may reproduce track-by-track reproductions of the real railroad in miniature, often using prototype track diagrams and historic maps.
Layouts vary from a circle or oval of track to realistic reproductions of real places modelled to scale. Probably the largest model landscape in the UK is in the Pendon Museum in Oxfordshire, UK, where an EM gauge (same 1:76.2 scale as 00 but with more accurate track gauge) model of the Vale of White Horse in the 1930s is under construction. The museum also houses one of the earliest scenic models – the Madder Valley layout built by John Ahern. This was built in the late 1930s to late 1950s and brought in realistic modelling, receiving coverage on both sides of the Atlantic in the magazines Model Railway News and Model Railroader. Bekonscot in Buckinghamshire is the oldest model village and includes a model railway, dating from the 1930s. The world's largest model railroad in H0 scale is the Miniatur Wunderland in Hamburg, Germany. The largest live steam layout, with 25 miles (40 km) of track is Train Mountain in Chiloquin, Oregon, U.S.
Operations form an important aspect of rail transport modelling with many layouts being dedicated to emulating the operational aspects of a working railway. These layouts can become extremely complex with multiple routes, movement patterns and timetabled operation. The British outline model railway of Banbury Connections in New South Wales, Australia, is one of the world's most complicated model railways.
Model railroad clubs exist where enthusiasts meet. Clubs often display models for the public. One specialist branch concentrates on larger scales and gauges, commonly using track gauges from 3.5 to 7.5 inches (89 to 191 mm). Models in these scales are usually hand-built and powered by live steam, or diesel-hydraulic, and the engines are often powerful enough to haul dozens of human passengers.
The Tech Model Railroad Club (TMRC) at MIT in the 1950s pioneered automatic control of track-switching by using telephone relays.
The oldest society is 'The Model Railway Club' (established 1910), near Kings Cross, London, UK. As well as building model railways, it has 5,000 books and periodicals. Similarly, 'The Historical Model Railway Society' at Butterley, near Ripley, Derbyshire specialises in historical matters and has archives available to members and non-members.
== Scales and gauges ==
The words scale and gauge seem at first interchangeable but their meanings are different. Scale is the model's measurement as a proportion to the original, while gauge is the measurement between the rails.
The size of engines depends on the scale and can vary from 700 mm (27.6 in) tall for the largest rideable live steam scales such as 1:4, down to matchbox size for the smallest: Z-scale (1:220) or T scale (1:450). A typical HO (1:87) engine is 50 mm (1.97 in) tall, and 100 to 300 mm (3.94 to 11.81 in) long. The most popular scales are: G scale, Gauge 1, O scale, S scale, HO scale (in Britain, the similar OO), TT scale, and N scale (1:160 in the United States, but 1:148 in the UK). HO and OO are the most popular. Popular narrow-gauge scales include Sn3, HOn3 and Nn3, which are the same in scale as S, HO and N except with a narrower spacing between the tracks (in these examples, a scale 3 ft (914 mm) instead of the 4 ft 8+1⁄2 in (1,435 mm) standard gauge).
The largest common scale is 1:8, with 1:4 sometimes used for park rides. G scale (Garden, 1:24 scale) is most popular for backyard modelling. It is easier to fit a G scale model into a garden and keep scenery proportional to the trains. Gauge 1 and Gauge 3 are also popular for gardens. O, S, HO, and N scale are more often used indoors.
At first, model railways were not to scale. Aided by trade associations such as the National Model Railroad Association (NMRA) and Normen Europäischer Modellbahnen (NEM), manufacturers and hobbyists soon arrived at de facto standards for interchangeability, such as gauge, but trains were only a rough approximation to the real thing. Official scales for the gauges were drawn up but not at first rigidly followed and not necessarily correctly proportioned for the gauge chosen. 0 (zero) gauge trains, for instance, operate on track too widely spaced in the United States as the scale is accepted as 1:48 whereas in Britain 0 gauge uses a ratio of 43.5:1 or 7 mm/1 foot and the gauge is near to correct. British OO standards operate on track significantly too narrow. The 4 mm/1 foot scale on a 16.5 mm (0.65 in) gauge corresponds to a track gauge of 4 ft 1+1⁄2 in (1,257 mm), 7 inches or 178 millimetres (undersized). 16.5 mm (0.65 in) gauge corresponds to 4 ft 8+1⁄2 in (1,435 mm) standard gauge in H0 (half-0) 3.5 mm/1 foot or 1:87.1. This arose due to British locomotives and rolling stock being smaller than those found elsewhere, leading to an increase in scale to enable H0 scale mechanisms to be used. Most commercial scales have standards that include wheel flanges that are too deep, wheel treads that are too wide, and rail tracks that are too large. In H0 scale, the rail heights are codes 100, 87, 83, 70, 55, 53, and 40 -- the height in thousandths of an inch from base to railhead (so code 100 is a tenth of an inch and represents 156-pound rail).
Later, modellers became dissatisfied with inaccuracies and developed standards in which everything is correctly scaled. These are used by modellers but have not spread to mass-production because the inaccuracies and overscale properties of the commercial scales ensure reliable operation and allow for shortcuts necessary for cost control. The finescale standards include the UK's P4, and the even finer S4, which uses track dimensions scaled from the prototype. This 4 mm:1 ft modelling uses wheels 2 mm (0.079 in) or less wide running on track with a gauge of 18.83 mm (0.741 in). Check-rail and wing-rail clearances are similarly accurate.
A compromise of P4 and OO is "EM" which uses a gauge of 18.2 mm (0.717 in) with more generous tolerances than P4 for check clearances. It gives a better appearance than OO though pointwork is not as close to reality as P4. It suits many where time and improved appearance are important. There is a small following of finescale OO which uses the same 16.5mm gauge as OO, but with the finer scale wheels and smaller clearances as used with EM- it is essentially 'EM-minus-1.7mm.'
== Modules ==
Many groups build modules, which are sections of layouts, and can be joined together to form a larger layout, for meetings or for special occasions. For each kind of module system, there is an interface standard, so that modules made by different participants may be connected, even if they have never been connected before. Many of these module types are listed in the Layout standards organizations section of this article.
== Couplers and connectors ==
In addition to different scales, there are also different types of couplers for connecting cars, which are not compatible with each other.
In HO, the Americans standardized on horn-hook, or X2F couplers. Horn hook couplers have largely given way to a design known as a working knuckle coupler which was popularized by the Kadee Quality Products Co., and which has subsequently been emulated by a number of other manufactures in recent years. Working knuckle couplers are a closer approximation to the "automatic" couplers used on the prototype there and elsewhere. Also in HO, the European manufacturers have standardized, but on a coupler mount, not a coupler: many varieties of coupler can be plugged in (and out) of the NEM coupler box. None of the popular couplers has any resemblance to the prototype three-link chains generally used on the continent.
For British modellers, whose most popular scale is OO, the normal coupler is a tension-lock coupler, which, again has no pretence of replicating the usual prototype three-link chain couplers. Bachmann and more recently Hornby have begun to offer models fitted with NEM coupler pockets. This theoretically enables modellers of British railways to substitute any other NEM362 coupler, though many Bachmann models place the coupler pocket at the wrong height. A fairly common alternative is to use representations of chain couplings as found on the prototype, though these require large radius curves to be used to avoid derailments.
Other scales have similar ranges of non-compatible couplers available. In all scales couplers can be exchanged, with varying degrees of difficulty.
== Landscaping ==
Some modellers pay attention to landscaping their layout, creating a fantasy world or modelling an actual location, often historic. Landscaping is termed "scenery building" or "scenicking".
Constructing scenery involves preparing a sub-terrain using a wide variety of building materials, including (but not limited to) screen wire, a lattice of cardboard strips, or carved stacks of expanded polystyrene (styrofoam) sheets. A scenery base is applied over the sub-terrain; typical base include casting plaster, plaster of Paris, hybrid paper-pulp (papier-mâché) or a lightweight foam/fiberglass/bubblewrap composite as in Geodesic Foam Scenery.
The scenery base is covered with substitutes for ground cover, which may be Static Grass or scatter. Scatter or flock is a substance used in the building of dioramas and model railways to simulate the effect of grass, poppies, fireweed, track ballast and other scenic ground cover. Scatter used to simulate track ballast is usually fine-grained ground granite. Scatter which simulates coloured grass is usually tinted sawdust, wood chips or ground foam. Foam or natural lichen or commercial scatter materials can be used to simulate shrubbery. An alternative to scatter, for grass, is static grass which uses static electricity to make its simulated grass actually stand up.
Buildings and structures can be purchased as kits, or built from cardboard, balsa wood, basswood, other soft woods, paper, or polystyrene or other plastic. Trees can be fabricated from materials such as Western sagebrush, candytuft, and caspia, to which adhesive and model foliage are applied; or they can be bought ready-made from specialist manufacturers. Water can be simulated using polyester casting resin, polyurethane, or rippled glass. Rocks can be cast in plaster or in plastic with a foam backing. Castings can be painted with stains to give colouring and shadows.
== Weathering ==
Weathering refers to making a model look used and exposed to weather by simulating dirt and wear on real vehicles, structures and equipment. Most models come out of the box looking new, because unweathered finishes are easier to produce. Also, the wear a freight car or building undergoes depends not only on age but where it is used. Rail cars in cities accumulate grime from building and automobile exhaust and graffiti, while cars in deserts may be subjected to sandstorms which etch or strip paint. A model that is weathered would not fit as many layouts as a pristine model which can be weathered by its purchaser.
There are many weather techniques that include, but are not limited to, painting (by either drybrushing or an airbrush), sanding, breaking, and even the use of chemicals to cause corrosion. Some processes become very creative depending on the skill of the modeller. For instance several steps may be taken to create a rusting effect to ensure not only proper colouring, but also proper texture and lustre.
Weathering purchased models is common, at the least, weathering aims to reduce the plastic-like finish of scale models. The simulation of grime, rust, dirt, and wear adds realism. Some modellers simulate fuel stains on tanks, or corrosion on battery boxes. In some cases, evidence of accidents or repairs may be added, such as dents or freshly painted replacement parts, and weathered models can be nearly indistinguishable from their prototypes when photographed appropriately.
== Methods of power ==
Static diorama models or "push along" scale models are a branch of model railways for unpowered locomotives, examples are Lone Star and Airfix models. Powered model railways are now generally operated by low voltage direct current (DC) electricity supplied via the tracks, but there are exceptions, such as Märklin and Lionel Corporation, which use alternating current (AC). Modern Digital Command Control (DCC) systems use alternating current. Other locomotives, particularly large models, can use steam. Steam and clockwork-driven engines are still sought by collectors.
=== Clockwork ===
Most early models for the toy market were powered by clockwork and controlled by levers on the locomotive. Although this made control crude the models were large and robust enough that handling the controls was practical. Various manufacturers introduced slowing and stopping tracks that could trigger levers on the locomotive and allow station stops.
=== Electricity ===
Three-rail
The first miniature electric trains used a three-rail track, with non-insulated wheels resting on the two outer rails that were in contact with the metal sleepers. The insulated central rail supplied the current to a skid under the locomotive. The outer rails ensured the return of the current. The current was alternating, supplied by the domestic network, lowered by various means (transformer or serial resistances). This kind of track made sense at the time as models were metal and conductive. Modern plastics were not available and insulation was a problem. In addition the notion of accurate models had yet to evolve and toy trains and track were crude tinplate.
In 1938, Hornby, a manufacturer of ‘O’ scale model trains in the UK, launched a range of ‘OO’ scale electric trains (Hornby Dublo) with 1/76 scale rolling stock using 1/87 scale 16.5 mm wide track with a third centre rail. The power supply was 12 V DC and the track was equipped with an electrically insulated central rail and two non-insulated running rails. In 1959 Hornby abandoned its three-rail track in favour of a two-rail track for its ‘OO’ scale electric trains.
Other systems such as Märklin instead used, since 1953, fine metal studs to replace the central rail, allowing existing three-rail models to use more realistic track.
A variation on the three-rail system, early introduced by Trix in 1935, used a track with three insulated rails that allowed two trains to be independently controlled on the same track. The use of a catenary made it possible for three trains to be independently controlled. The center rail ensured the common return of the current. That system, known as Trix Express or Trix Twin in the UK, which first used alternative current and then direct current after 1953, was abandoned in 1997 when Märklin took over Trix. This three-rail system enabled DC and AC locomotives to run on the same track.
Two-rail
When DC motors with more powerful magnets began to be used for model trains in the 1950s, the two-rail track was generally preferred because at the same time accuracy became important. The two insulated rails from each other are to be used with insulated wheels on the same axle. In the direction of travel, the right-hand rail carries the positive potential and the left-hand rail the negative. This system excludes certain track layouts such as the reversing loop, the reversing triangle and the diagonal in a circle without insulated sections and suitable cabling.
Overhead line
Where the model is of an electric locomotive, it may be supplied by overhead lines, like the full-size locomotive. Before Digital Command Control became available, this was one way of controlling two trains separately on the same track. The electric-outline model would be supplied by the overhead wire and the other model could be supplied by one of the running rails. The other running rail would act as a common return.
Battery
Early electric trains ran on trackside batteries because few homes in the late 19th century and early 20th century had electricity. Today, inexpensive train sets running on batteries are again common but regarded as toys and seldom used by hobbyists. Batteries located in the model often power garden railway and larger scale systems because of the difficulty in obtaining reliable power supply through the outdoor rails. The high-power consumption and current draw of large-scale garden models is more easily and safely met with internal rechargeable batteries. Most large-scale battery-powered models use radio control.
=== Live steam ===
Engines powered by live steam are often built in large outdoor gauges of 5 inches (130 mm) and 7+1⁄2 inches (190 mm), are also available in Gauge 1, G scale, 16 mm scale and can be found in O and OO/HO. Hornby Railways produce live steam locomotives in OO, based on designs first arrived at by an amateur modeller. Other modellers have built live steam models in HO/OO, OO9 and N, and there is one in Z in Australia.
=== Internal combustion ===
Occasionally gasoline-electric models, patterned after real diesel-electric locomotives, come up among hobbyists and companies like Pilgrim Locomotive Works have sold such locomotives. Large-scale petrol-mechanical and petrol-hydraulic models are available but unusual and pricier than the electrically powered versions.
== Scratch building ==
Modern manufacturing techniques can allow mass-produced models to cost-effectively achieve a high degree of precision and realism. In the past this was not the case and scratch building was very common. Simple models are made using cardboard engineering techniques. More sophisticated models can be made using a combination of etched sheets of brass and low temperature castings. Parts that need machining, such as wheels and couplings are purchased.
Etched kits are still popular, still accompanied by low temperature castings. These kits produce models that are not covered by the major manufacturers or in scales that are not in mass production. Laser machining techniques have extended this ability to thicker materials for scale steam and other locomotive types. Scratch builders may also make silicone rubber moulds of the parts they create, and cast them in various plastic resins (see Resin casting), or plasters. This may be done to save duplication of effort, or to sell to others. Resin "craftsman kits" are also available for a wide range of prototypes.
== Control ==
The first clockwork (spring-drive) and live steam locomotives ran until out of power, with no way for the operator to stop and restart the locomotive or vary its speed. The advent of electric trains, which appeared commercially in the 1890s, allowed control of the speed by varying the current or voltage. As trains began to be powered by transformers and rectifiers more sophisticated throttles appeared, and soon trains powered by AC contained mechanisms to change direction or go into neutral gear when the operator cycled the power. Trains powered by DC can change direction by reversing polarity.
Electricity permits control by dividing the layout into isolated blocks, where trains can be slowed or stopped by lowering or cutting power to a block. Dividing a layout into blocks permits operators to run more than one train with less risk of a fast train catching and hitting a slow train. Blocks can also trigger signals or other accessories, adding realism or whimsy. Three-rail systems often insulate one of the common rails on a section of track, and use a passing train to complete the circuit and activate an accessory.
Many layout builders are choosing digital operation of their layouts rather than the more traditional DC design. Of the several competing systems, the command system offered by the majority of manufacturers in 2020 was a variant of Digital Command Control (DCC). The advantages of DCC are that track voltage is constant (usually in the range of 20 volts AC) and the command throttle sends a signal to small circuit cards, or decoders, hidden inside the piece of equipment which control several functions of an individual locomotive, including speed, direction of travel, lights, smoke and various sound effects. This allows more realistic operation in that the modeller can operate independently several locomotives on the same stretch of track. Several manufacturers also offer software that can provide computer-control of DCC layouts.
In large scales, particularly for garden railways, radio control and DCC in the garden have become popular.
== Model railway manufacturers ==
Model railways
== Magazines ==
== Layout standards organizations ==
Several organizations exist to set standardizations for connectibility between individual layout sections (commonly called "modules"). This is so several (or hundreds, given enough space and power) people or groups can bring together their own modules, connect them together with as little trouble as possible, and operate their trains. Despite different design and operation philosophies, different organizations have similar goals; standardized ends to facilitate connection with other modules built to the same specifications, standardized electricals, equipment, curve radii.
ausTRAK, N Scale, two-track main with hidden third track (can be used as NTRAK's third main, as a return/continuous loop, or hidden yard/siding/on-line storage). Australian scenery and rolling stock modelled in Standard Gauge.
FREMO a European-based organisation focusing on a single-track line, HO Scale. Also sets standards for N Scale modules. Standards are considerably more flexible in module shape than NTRAK, and has expanded over the years to accommodate several scenery variations.
Free-mo Originally developed by the San Luis Obispo Model Railroad Club in 1995 (California), it has grown across North America and is expanding across the world. The objective of the Free-mo Standard is to provide a platform for prototype modelling in a flexible, modular environment. Free-mo modules not only provide track to operate realistic models, but also emphasize realistic, plausible scenery; realistic, reliable trackwork; and operations. Free-Mo was designed to go beyond the traditional closed-loop set-up in creating a truly universal "free-form" modular design that is operations-oriented and heavily influenced by prototype railroading. This is emphasized in the Free-mo motto, "More than Just a Standard".
MOROP, European Union of Model Railroad and Railroad Fans, the European standardization organisation.
NEM, The German modelling standards organisation.
NMRA, National Model Railroad Association, the largest organization devoted to the development, promotion, and enjoyment of the hobby of model railroading.
N-orma, Polish N-scale (1:160) modules organization.
NTRAK, standardized three-track (heavy operation) mainline with several optional branchlines. Focuses on standard gauge, but also has specifications for narrow gauge. Due to its popularity, it can be found in regional variations, most notably the imperial-to-metric measurement conversions. Tends to be used more for "unattended display" than "operation".
oNeTRAK, operationally similar to FREMO, standardises around a single-track mainline, with modules of varying sizes and shapes. Designed with the existing NTRAK spec in mind, is fully compatible with such modules.
Sipping and Switching Society of NC is a society/association of individuals which has developed a system of HO modules, which feature lightweight waffle construction using 5 mm lauan plywood underlayment and an interface which depends on using a metal template to locate 1-inch (25 mm) pegs to mate to 1-inch holes in the adjoining module. The rails of the tracks are positioned in an exact relationship with the pegs. The rails come up to the end of the modules, so that the rails on adjacent modules do not need joiner track, but depend on the accuracy of the placement of the rails to allow trains to pass from one section to another. This style of module allows for very quick set-up, compared with module systems that use joiner tracks.
sTTandard, Polish TT-scale (1:120) modules organization.
T-TRAK, is a modular system that uses table-top modules, 2+3⁄4 inches (70 mm) high, which set on tables, that are not part of the modules, but are often found at sites which members meet. It uses a specific track interface, which has joiners which hold the modules together, which enables quick setting up and taking down.
Z-Bend Track, uses a double-track mainline running down both sides of a module. Modules can be of any length or width in the middle and any overall shape. The "standard" called Z-Bend Track applies only to the last 5 inches (130 mm) of the module's interface to other modules, the electrical interface and the module height.
== In popular culture ==
In the 1990 film Back to the Future III, Doc brown builds a "crude" electrified model rail "not to scale" to demonstrate his time travel experiment to Marty in 1885.
In Hinterland Season 1, Episode 4 ("The Girl in the Water"), a semi-recluse who lives and works at Borth railway station maintains a model train set with custom made components; the set and certain components contribute to a death as well as provide important clues to a murder investigation. During the investigation, DCI Tom Mathias reveals that his late brother was a model train aficionado.
In The Sopranos, Bobby Baccalieri is a model train aficionado. He is shown wearing an engineer's cap while playing with model trains in his garage.
In The Simpsons, Reverend Lovejoy is often depicted playing with his model trains when not on ecumenical duty, often while wearing a conductor's uniform and hat. His character may be a nod to the real life Reverend W. Awdry.
In Trailer Park Boys, Season 7 Episode 4, "Friends of the Dead", heavy metal singer Sebastian Bach is a featured guest at the Bangor model train convention and is introduced as "our Competitive Model Train World Champion". He expresses a dislike of alleged rival model train competitor Patrick Swayze. Attendees at the family event are shocked by Sebastian's use of obscenities as he attempts to work the crowd in a rock concert fashion shouting, "I know, I just know, that there are some great f**king trains here in Bangor!"
In That '90s Show, Red Forman runs a model railway in the garage after he retired.
== See also ==
Displays and famous layouts
Groups dedicated to railway modelling
== References ==
== External links ==
The National Model Railroad Association, USA – the largest model railroad organization in the world
The Model Railway Club, UK – the oldest known society in the world – established 1910
Associazione Ferrovie Siciliane – AFS (Messina – IT) – One of the most important group of rail enthusiasts end railways modellers active in Sicily and all over Italy founded in 2006 | Wikipedia/Model_railroading |
The Aurora Plastics Corporation was an American toy and hobby manufacturing company. It is known primarily for its production of plastic scale models of cars, airplanes, and TV and movie figures in the 1960s. Its principal competition in modeling were various other plastic modeling firms like Revell and Monogram.
Established in 1950, the company was first sold in 1969, being then acquired by other firms until then-parent company Dunbee-Combex-Marx ceased operations in 1980. Since then, the Giammarino family have tried to reintroduce the Aurora brand, but their attempts never carried out.
== History ==
Aurora Plastics Corporation was founded in March 1950 by engineer Joseph E. Giammarino (1916–1992) and businessman Abe Shikes (1908–1986) in Brooklyn, New York (moving to West Hempstead, Long Island in 1954), as a contract manufacturer of injection molded plastics.
With the hiring in 1952 of salesman John Cuomo (1901–1971), the company began the manufacture of its own line of plastic model kits, efficiently marketed with a skeleton staff. The target market were young hobbyists, similar to the kits of the rival companies, Monogram and Revell. Aurora profitably targeted a younger demographic than their competitors, creating smaller-sized, less detailed models at a lower price.
The first kits came in late 1952 and were 1:48 scale aircraft models. One was a F9F Panther jet and the other an F90 Lockheed. The Aurora logo at this time appeared in narrow white letters and in a semi-circular form across the top of the script; the more recognized Aurora oval did not appear until 1957. Boxes were a simply illustrated orange color. The slogan under the Aurora logo was "U – Ma – Kit" (You Make It). Aurora's market approach was to make kits simple, thus undercutting the competition. Along these lines these first two kits appear to have been Hawk kits measured and copied to Aurora's own molds.
By 1953, six more dies had been made for new airplanes: the Curtiss P-40E Warhawk, Messerschmitt Bf 109, North American F-86D, and the Lockheed P-38L Lightning, and a fictitious Russian "Yak-25" (later sold as "Mig-19"). Lastly was the Mitsubishi Zero, called the "Jap Zero" on the box flaps. With the first two Hawk copies, this collection was called the "Brooklyn Eight".
== Product lines ==
=== Aircraft mainstay ===
Aurora Plastic's first kits were aircraft and this was a backbone of sales through the 1950s and 1960s. From early on the company's Famous Fighters line was popular. Included were World War I, World War II, jet age aircraft and a variety of whirlybirds. A series of aircraft from the 1930s were also offered. Sailing ships, warships, tanks and other military vehicles were available as well. One World War I airplane was the DeHavilland Airco DH.4. Many planes, like the Blue Angel F-4J, McDonnell-Douglas Phantom II and the LTV A-7D Corsair II, were offered in a larger 1/48 scale. Others were smaller scale such as the Boeing KC-135 Stratotanker in about 1:100, because it would have been over two feet long in 1/48; and even smaller, like the Convair B-58 Hustler bomber in a diminutive 1:200 scale, or about 6 inches long.
=== Automotive kits ===
By 1965, Aurora had many automobile kits in 1:32 "slot car" scale including the Triumph TR3, MG-TD, Jaguar XK120, Austin-Healey 3000, Alfa Romeo GT convertible, Mercedes-Benz 300 SL convertible, 1958 Ford "Squarebird" Thunderbird, the American Cunningham, and a few Indianapolis 500 winners, like the Monroe Special, and the Fuel Injection Special.
=== Media tie-ins ===
Aurora probably had their biggest success with their kits of figures. These included a series of popular historical knights in armor, and other still life buildings, animals, boats, and other intriguing objects. Guys and Gals of all Nations were also produced and included Dutch, Chinese, Indian, Scottish and Mexican figures.
Aurora acquired a license from Universal Studios to create a line of kits based on the Universal monsters, which became the company's most popular offerings. Aurora's kit of Frankenstein appeared in 1961. Giant Frankenstein was an all-plastic kit that, when assembled, created a 19-inch tall model. This was followed by 12 other monster figures that were issued and reissued in various versions through the early 1970s. These included RKO Pictures' King Kong, and characters from Toho Studios: Godzilla, and later in 1975, Ghidrah (Ghidorah), and Rodan. After this, monster vehicles such as Dracula's Dragster, Frankenstein's Flivver, Godzilla's Go-Cart, King Kong's Thronester, Mummy's Chariot and Wolfman's Wagon were introduced, fortifying the company's car offerings.
Licensed models based on characters from movies, TV shows and comic books were also introduced. Some of the most popular licensed products were the Batmobile and other vehicles from the 1966 TV series, launched in 1967. Batman was a regular offering as was the Hulk, so both DC and Marvel characters were represented. Model kits from Twelve O'Clock High, The Man from U.N.C.L.E., The Mod Squad, Voyage to the Bottom of the Sea (the larger Seaview sub and a separate kit of its flying sub), The Invaders, Lost in Space, Land of the Giants and Star Trek appeared. These kits were often a television-related scene where heroes battled some kind of large monster, alien or animal. Aurora’s figure kits continue to be highly valued by collectors. Aurora used artist James Bama for some of their box art.
=== Model motoring ===
In the late 1950s, Aurora acquired the rights to the Model Motoring slot car racing system from UK toy manufacturer Playcraft. Aurora's first HO-gauge racing sets appeared in the fall of 1960.
The cars were originally driven by a unique, vibrator drive system based on a door "buzzer." This motor comprised a wire coil around a vertical iron plunger which very quickly opened and closed a contact which fed power to the coil, and also drove a reed up and down that engaged a toothed drum on the rear axle, causing it to turn. When these early cars ran down the track they produced a loud "buzz," which many users found irritating. The vibrator car was produced until 1963 when the Thunderjet pancake motor, or T-jet, replaced it. Following improvements in the chassis with the Thunderjet and A/FX series and the adoption of popular racing car body styles, Aurora's Model Motoring race sets became top sellers, with over 25,000,000 cars sold by 1965.
Part of the popularity of the Pancake motor cars was that they could easily be disassembled by the hobbyist with the simple removal of the brass gearplate clip which gave ready access to the armature, brushes and magnets, and serviced with readily available factory original replacement and upgrade parts. These upgrades included silver plated electrical parts for better electrical conductivity, and gears to raise the gear ratio to achieve higher speeds. Third party hop up parts and specialty tools soon came into the market, including stronger motor magnets, wider axles, wider wheels made of precision molded plastic or machined aluminum, brass axle weights to hold the front guide pin in the guide slot at higher cornering speed, and wider soft silicone tires that had better traction. Tools included pickup shoe benders, miniature gear and wheel pullers, gear and wheel presses. Another factor was that Aurora produced updates to the Pancake motor cars like the Thunderjet Tuff Ones, including hotter armatures, wider stance, wider tires, and later, magnatraction added to the A/FX chassis.
Magnatraction was accomplished by equipping the A/FX chassis with thicker motor magnets which extended lower into openings of the chassis, using magnetic attraction to the electrical rails in the track and pulling the chassis down which gave the tires better traction, resulting in higher speed and harder cornering. Many enthusiasts liked the higher speed, while others preferred the non-magnatraction cars. The non-magnatraction cars, although slower, allowed the rear end of the car to slide, or "drift" through the corners, creating a danger zone that allowed drivers to drive the car hard into the danger zone before reaching the crash point. Another part of the fun was the ability to slide the rear of the car and "nerf" a competitor's car off the track if the two went into a curve side by side. The magnatraction cars did not have this drift, and while cornering faster, the driver did not have this danger zone. The car would without warning crash off the track if the driver went into the corner too hard.
By the end of the 1970s, however, the slot car craze had passed and modeling in general was on the decline. One website attributes the decline to both the maturing of the baby-boom generation along with the fragile economics of the slot car industry and the closing of many slot car shops as toy companies offered smaller sets to be used at home.
But that did not mean the end of the legendary pancake motor cars. They had their enthusiasts that kept them alive, along with a large supply of new old stock, and companies continued to make third party parts. New body designs and reproductions of original bodies and chassis were produced under the names of Johnny Lightning, Playing Mantis, Round2, Auto World, and Hot rod. These reproductions were embraced by enthusiasts because they could modify the reproduction bodies instead of cutting vintage ones. These mods included grinding excess weight off the inside of the body, and cutting the mounting posts to lower the bodies in order to lower the center of gravity. Wheel wells would be cut to allow wider tires and lowering of the body. Reproductions were produced as recently as the year 2020, and some of them are still on hobby store shelves as of 2021. There is a vibrant community of small sellers on internet market and auction sites, and a few remaining shops with multi lane professional tracks still exist along with clubs whose members travel to other states for national sanctioned races. Some of these events are run with the name of "The Fray", and have a specific set of rules on how cars can be modified, and what parts must be in the original configuration. These races have a tech inspection afterwards for the cars that win prizes or points towards a national championship.
=== Cigarbox competes with Hot Wheels ===
In 1968, Aurora introduced its Cigarbox miniature cars and the timing could not have been worse. These were developed to compete with Matchbox in the year that Mattel's Hot Wheels were introduced. The Cigarbox car line was a combination of rather bland plastic slot car bodies with metal chassis. Models were claimed to be HO scale, but the cars were larger than HO – yet a bit smaller than Hot Wheels.
Cigarbox cars were packaged in small yellow cigar-like boxes which had fancy red serif lettering and gold trim. The boxes were slightly larger, flatter and more rectangular than those of Matchbox, measuring 4" x 2.75" x just over 1" deep. If Lesney could have "Match" boxes, Aurora figured it could have "Cigar" boxes. The popular rumor was that Matchbox took Aurora to court for copyright infringement over the similar marketing approach. Today the idea skirts the boundaries of the culturally acceptable. Was smoking being promoted? In any event, the Cigarbox marque soon disappeared.
Some of the cars offered, however, were unique and not often seen in miniature, such as the 1967 Ford Galaxie 500, 1963 Buick Riviera, Mako Shark Corvette concept, Cheetah Chevy, Lola GT racing coupe, and the Porsche 904. Several Formula 1 cars were also offered in the series.
Initially, most cars were offered in rather plain colored plastic bodies with high friction ('squeaky') wheels, though their rubber tires were more authentic than hard plastic – making them somewhat similar to Matchbox tradition. Some of the cars, such as the De Tomaso Mangusta, had working steering. Eventually, thinner, low-friction wheels (some chromed and some not) were added and chrome-like shiny paint finishes were introduced, making the cars flashy, but competition was keen and financial troubles loomed. These improved versions were sold under the Speed Line name, and also as slot car bodies and in kit form, but the line was discontinued by 1970.
== Logo use and retooling ==
Aurora's founders retired in the late 1960s and the company was sold to outside investors in 1969. After expanding into the toys and games market with limited success, the new owners sold the company to Nabisco in 1971. Nabisco received unwanted publicity when Aurora introduced a line of “Monster Scenes” which included torture devices and a scantily clad female victim; newspapers reported negatively on the line, and the National Organization for Women voiced their objection. Seven years after their acquisition, Nabisco sold the company to the Anglo-US toy company Dunbee-Combex-Marx who also owned the Scalextric racing system and Frog kits for $11.5m. Aurora had been loss-making for a number of years but Dunbee-Combex-Marx failed to turn Aurora around and ended up failing itself in 1980.
In the late 1990s and early 2000s, toy and hobby company Playing Mantis created a division called "Polar Lights" (as a reference to Aurora) which reissued some of Aurora's most popular kits. Other companies following in Aurora's shoes have reissued earlier kits. These companies include "Moebius Models", "Atlantis Models" and "Monarch Models", which mostly have focused on the Aurora sci-fi and horror TV and movie figures and scenes. For example, Moebius Models, started by a former distributor of Polar Lights models in Glenwood, Florida, has reissued the large kit of the submarine Seaview from the 1960s Voyage to the Bottom of the Sea TV show and the old Dr. Jekyll as Mr. Hyde kit. Monarch Models, now Monarch Model Company, is based in London, Ontario, Canada – started by a doctor. Atlantis Models is based in Deer Park, New York, and though also making sci-fi figures, has equal focus on animal dioramas. In 2018 Atlantis Purchased most of the Aurora Tooling that remained at Revell Monogram in Elk Grove. Polar Lights, Monarch and Moebius all use an oval logo very similar in shape to that of the original Aurora style. The Atlantis (see Zorro re-issue) logo uses a more abstract, though nostalgic, oval broken into six sections.
In the 1990s, the family of Joseph Giammarino announced the return of Aurora Plastics Corporation as a manufacturer of hobby kits under the name LAPCO, or Lost Aurora Plastics Corporation, with a product line to include reverse engineered reissues of long-gone kits. Nothing came of this. Again in 2007, Giammarino's family announced the return of Aurora, with their first offerings stated to include aircraft and figure kits from their original 1960s line. This website lists products to be made available in May–June 2012, but as of November 2018, none are available to order and the site appears to have not been updated.
== Bibliography ==
Gosson, Scotty (2015). Show Rod Model Kits. A Showcase of America's Wildest Model Kits. Forest Lake MN: CarTech Publishing. ISBN 9781613251560.
Ragan, Mac (2000). Diecast Cars of the 1960s. Osceola WI: Motorbooks. ISBN 978-0760307199.
== References ==
== External links ==
Official website (archived, 6 Aug 2018)
Aurora models on Collecttoys.com (archived)
Aurora Godzilla's Go Cart 1966 - Godzilla Monster Gallery on DonCapone.org
Aurora Stunt and Drag Race Set Commercial — Public Domain, Prelinger Archives.
Aurora Speedline Commercial | Wikipedia/Polar_Lights_(models) |
Model robots are model figures with origins in the Japanese anime genre of mecha. The majority of model robots are produced by Bandai and are based on the Gundam anime metaseries. This has given rise to the hobby's common name in Japan, Gunpla (or gan-pura, a Japanese portmanteau of "Gundam" and "plastic model"). Though there are exceptions, the model robot genre is dominated by anime tie-ins, with anime series and movies frequently serving as merchandising platform.
== Construction ==
Gundam kits are the most common and popular variety of mecha models exemplifying the general characteristics of models in the genre. Gundam kits are typically oriented toward beginners, and most often feature simple assembly, simple designs, and rugged construction—less durable than a pre-assembled toy, but more durable than a true scale model. The result is that the majority of Gundam kits feature hands and other parts that favor poseability or easy assembly over accurate shape. They may also exhibit various draft-angle problems, and features like antennae that are oversized to prevent breakage. For the most part, other kit lines and other kit manufacturers in the genre follow suit, though there are exceptions.
Because the subjects of model robot kits are typically humanoid and/or possess limbs, joints are required in order to make the finished model poseable. For decades, poly-caps were and still are used for this purpose, although they tend to degrade over time and thus have been less frequently used since the 2010s. Hard plastic joints generally exhibit greater friction than polyvinyl joints, and are similarly more durable than polystyrene joints. ABS joints, however, require greater precision in tooling to ensure easy assembly, and in some cases, they require screws and a small gap between parts.
One distinctive feature of model robot kits since the 1990s, as opposed to most other plastic model kits, is that they are molded in color: each part generally is made of a colored plastic corresponding to its intended color on the finished model. Bandai in particular has become well-known for its use of multi-color molding, which allows parts of different colors to be molded on the same sprue. In some cases, compromises have to be made - for instance, molding a part in an incorrect color, or a two-colored part in only one color - to ensure that the model is structurally stable and not overly complex, particularly when the intended retail price is low. One criterion by which enthusiasts assess the quality of a kit is its color-accuracy - that is to say, the correspondence between the molded color of the parts and the intended color of the finished model.
== Scale and Grade ==
Anime mecha subjects such as Gundam are most often portrayed as being between 15 and 20 meters tall, so the kits are scaled in a manner that brings the subject to an economical and manageable size. For machines in this size range, scales of 1:100 and 1:144 are most common, with 1:60 being reserved for larger (and usually more expensive or elaborate) kits. For smaller subjects, scales such as 1:20, 1:35, and 1:72 are also common. Bandai kits will commonly use a fairly extensive redesign, rather than the original design itself. Some of this inconsistency in representation may be due to the inherent difficulties in turning a 2-D cel-animated design into a 3-D design. Additionally, newer versions of the same model could be very different from an older version, due to better manufacturing technologies.
Gunpla kits are also sorted by a grading scale, which signals the complexity, and sometimes the art style, of the model.
== Practice ==
Gunpla is a major hobby in Japan, with entire magazines dedicated to variations on Bandai models. As mecha are fictional humanoid objects, there is considerable leeway for custom models and "kitbashes." A large amount of artistry goes into action poses and personalized variations on classic machines. There is also a market for custom resin kits which fill in gaps in the Bandai model line.
Gundam is not the only line of model robots. Eureka Seven, Neon Genesis Evangelion, Patlabor, Aura Battler Dunbine and Heavy Metal L-Gaim, to name a few, are all represented by Bandai model lines. Other manufacturers, such as Hasegawa, Wave, and Kotobukiya, have in recent years offered products from other series, such as Macross, Votoms, Five Star Stories, Armored Core, Virtual-On, Zoids, and Maschinen Krieger, with sales rivaling Bandai's most popular products.
== References == | Wikipedia/Model_robot |
A model aircraft is a physical model of an existing or imagined aircraft, and is built typically for display, research, or amusement. Model aircraft are divided into two basic groups: flying and non-flying. Non-flying models are also termed static, display, or shelf models.
Aircraft manufacturers and researchers make wind tunnel models for testing aerodynamic properties, for basic research, or for the development of new designs. Sometimes only part of the aircraft is modelled.
Static models range from mass-produced toys in white metal or plastic to highly accurate and detailed models produced for museum display and requiring thousands of hours of work. Many are available in kits, typically made of injection-molded polystyrene or resin.
Flying models range from simple toy gliders made of sheets of paper, balsa, card stock or foam polystyrene to powered scale models built up from balsa, bamboo sticks, plastic, (including both molded or sheet polystyrene, and styrofoam), metal, synthetic resin, either alone or with carbon fiber or fiberglass, and skinned with either tissue paper, mylar and other materials. Some can be large, especially when used to research the flight properties of a proposed full scale aircraft.
== Aerodynamic research and mock-ups ==
Models are made for wind tunnel and free-flight research tests and may have components that can be swapped to compare various fittings and configurations, or have features such as controls that can be repositioned to reflect various in flight configurations. They are also often fitted with sensors for spot measurements and are usually mounted on a structure that ensures the correct alignment with the airflow, and which provides additional measurements. For wind tunnel research, it is sometimes necessary only to make part of the proposed aircraft.
Full-scale static engineering models are also constructed for production development, often made of different materials from the proposed design. Again, often only part of the aircraft is modelled.
== Static display models ==
Static model aircraft cannot fly, and are used for display, education and are used in wind tunnels to collect data for the design of full scale aircraft. They may be built using any suitable material, which often includes plastic, wood, metal, paper and fiberglass and may be built to a specific scale, so that the size of the original may be compared to that of other aircraft. Models may come finished, or may require painting or assembly, with glue, screws, or by clipping together, or both.
Many of the world's airlines allow their aircraft to be modelled for publicity. Airlines used to order large scale models of their aircraft to supply them to travel agencies as a promotional item. Desktop model airplanes may be given to airport, airline and government officials to promote an airline or celebrate a new route or an achievement.
=== Scale ===
Static model aircraft are primarily available commercially in a variety of scales from as large as 1:18 scale to as small as 1:1250 scale. Plastic model kits requiring assembly and painting are primarily available in 1:144, 1:72, 1:48, 1:32, and 1:24 scale. Die-cast metal models (pre-assembled and factory painted) are available in scales ranging from 1:48 to 1:600.
Scales are not random, but are generally based on divisions of either the Imperial system, or the Metric system.
For example, 1:48 scale is 1/4" to 1-foot (or 1" to 4 feet) and 1:72 is 1" to 6 feet, while in metric scales such as 1:100th, 1 centimeter equals 1 meter.
1:72 scale was introduced with Skybirds wood and metal model aircraft kits in 1932 and were followed closely by Frog, which used the same scale from 1936 with their "Frog Penguin" brand. 1:72 was popularized in the US during the Second World War by the US War Department after it requested models of commonly encountered single engine aircraft at that scale, and multi-engine aircraft in 1:144th scale. They hoped to improve aircraft recognition skills and these scales compromised between size and detail. After WWII, manufacturers continued with these scales, however kits are also added in other divisions of the imperial system. 1:50th and 1:100th are common in Japan and France, which both use Metric. Promotional models for airlines are produced in scales ranging from 1:200 to 1:1200.
Some manufacturers made 1:18th scale aircraft to go with cars of the same scale. Aircraft models, military vehicles, figures, cars, and trains all have different common scales but there is some crossover. There is a substantial amount of duplication of more famous subjects in different scales, which can be useful for forced perspective box dioramas.
Older models often did not conform to an established scale as they were sized to fit the box, and are referred to as being to "Box Scale".
=== Materials ===
The most common form of manufacture for kits is injection molded polystyrene plastic, formed in steel forms. Plastic pellets are heated into a liquid and forced into the mold under high pressure through trees that hold all the parts, and ensure plastic flows to every part of the mold. This allows a greater degree of automation than other manufacturing processes but molds require large production runs to cover the cost of making them. Today, this takes place mostly in Asia and Eastern Europe. Smaller runs are possible with copper molds, and some companies use resin or rubber molds, but while the cost is lower for the mold, the durability is also lower and labor costs can be much higher.
Resin kits are made in forms similar to those used for limited run plastic kits, but these molds are usually not as durable, which limits them to smaller production runs, and prices for the finished product are higher.
Vacuum forming is another common alternative but requires more skill, and details must be supplied by the modeller. There is a handful of photo etched metal kits that allow a high level of detail and they are unable to replicate compound curves.
Scale models can also be made from paper or card stock. Commercial models are mainly printed by publishers in Germany or Eastern Europe but can be distributed through the internet, some of which are offered this way for free.
From World War I through the 1950s, static model airplanes were also built from light weight bamboo or balsa wood and covered with tissue paper in the same manner as with flying models. This was a time-consuming process that mirrored the actual construction of airplanes through the beginning of World War II. Many model makers would create models from drawings of the actual aircraft.
Ready-made desk-top models include those produced in fiberglass for travel agents and aircraft manufacturers, as well as collectors models made from die-cast metal, mahogany, resin and plastic.
Carbon fibers and fiberglass have become increasingly common in model aircraft kits. In model helicopters, main frames and rotor blades are often made from carbon fiber, along with ribs and spars in fixed-wing aircraft wings.
== Flying models ==
Aeromodelling is the building and operation of flying model aircraft. Some flying models resemble scaled down versions of full scale aircraft, while others are built with no intention of looking like real aircraft. There are also models of birds, bats and pterosaurs (usually ornithopters). The reduced size affects the model's Reynolds number, which determines how the air reacts when flowing past the model, and compared to a full sized aircraft the size of control surfaces needed, the stability and the effectiveness of specific airfoil sections may differ considerably requiring changes to the design.
=== Control ===
Flying model aircraft are generally controlled through one of three methods
Free flight (F/F) model aircraft are uncontrolled other than by control surfaces that must be preset before flight, and must have a high degree of natural stability. Most free flying models are either unpowered gliders or rubber powered. These pre-date manned flight.
Control line (C/L) model aircraft use strings or wires to tether the model to a central pivot, either held by hand or to a pole. The aircraft then flies in circles around that point, secured by one cable, while a second provides pitch control through a connection to the elevator. Some use a third cable to control a throttle. There are many competition categories. Speed flying is divided into classes based on engine displacement. Class 'D' 60 size speed planes can easily reach speeds well in excess of 150 mph (240 km/h).
Radio-controlled aircraft have a controller who operates a transmitter that sends signals to a receiver in the model to actuate servos that adjust the model's flight controls similarly to a full sized aircraft. Traditionally, the radio signal directly controlled servos, however, modern examples often use flight control computers to stabilize the model or even to fly it autonomously. This is particularly the case with quadcopters. Rudimentary flight controllers were first introduced in model helicopters, with standalone electronic gyroscopes used stabilize the tail rotor control. Much like quadcopters, this has now extended to all flight controls.
=== Construction ===
Flying models construction may differ from that of static models as both weight and strength are major considerations.
Flying models borrow construction techniques from full-sized aircraft although the use of metal is limited. These might consist of forming a frame using thin planks of a light wood such as balsa to duplicate the formers, longerons, spars, and ribs of a vintage full-size aircraft, or, on larger (usually powered) models where weight is less of a factor, sheets of wood, expanded polystyrene, and wood veneers may be employed. It is then given a smooth sealed surface, usually with aircraft dope. For light models, tissue paper is used. For larger models (usually powered and radio controlled) heat-curing or heat shrink covering plastic films or heat-shrinkable synthetic fabrics are applied to the model. Microfilm covering is used for the lightest models and is made by spreading few drops of lacquer out over several square feet of water, and lifting a wire loop through it, which creates a thin plastic film.
Flying models can be assembled from kits, built from plans, or made completely from scratch. A kit contains the necessary raw material, typically die- or laser-cut wood parts, some molded parts, plans, assembly instructions and may have been flight tested. Plans are intended for the more experienced modeller, since the builder must make or find the materials themselves. Scratch builders may draw their own plans, and source all the materials themselves. Any method may be labor-intensive, depending on the model in question.
To increase the hobby's accessibility, some vendors offer Almost Ready to Fly (ARF) models that minimize the skills required, and reduce build time to under 4 hours, versus 10–40 or more for a traditional kit. Ready To Fly (RTF) radio control aircraft are also available, however model building remains integral to the hobby for many. For a more mass market approach, foamies, injection-molded from lightweight foam (sometimes reinforced) have made indoor flight more accessible and many require little more than attaching the wing and landing gear.
=== Gliders ===
Gliders do not have an attached powerplant. Larger outdoor model gliders are usually radio-controlled gliders and hand-winched against the wind by a line attached to a hook under the fuselage with a ring, so that the line drops when the model is overhead. Other methods include catapult-launching, using an elastic bungee cord. The newer "discus" style of wingtip hand-launching has largely supplanted the earlier "javelin" type of launch. Also using ground-based power winches, hand-towing, and towing aloft using a second powered aircraft.
Gliders sustain flight through exploitation of the wind in the environment. A hill or slope often produces updrafts of air that sustain the flight of a glider. This is called slope soaring, and radio controlled gliders can remain airborne for as long as the updraft remains. Another means of attaining height in a glider is exploitation of thermals, which are columns of warm rising air created by differences of temperature on the ground such as between an asphalt parking lot and a lake. Heated air rises, carrying the glider with it. As with a powered aircraft, lift is obtained by the action of the wings as the aircraft moves through the air, but in a glider, height is gained by flying through air that is rising faster than the aircraft is sinking.
Walkalong gliders are lightweight model airplanes flown in the ridge lift produced by the pilot following in close proximity. In other words, the glider is slope soaring in the updraft of the moving pilot (see also Controllable slope soaring).
=== Power sources ===
Powered models contain an onboard powerplant, a mechanism powering propulsion of the aircraft through the air. Electric motors and internal combustion engines are the most common propulsion systems, but other types include rocket, small turbine, pulsejet, compressed gas, and tension-loaded (twisted) rubber band devices.
==== Rubber ====
The oldest method of powering free flight models is Alphonse Pénaud's elastic motor (or extensible motor) of 1871, essentially a long rubber band that is twisted to add tension, prior to flight. It is the most widely used powerplant, found on everything from children's toys to competition models. The elastic offers simplicity and durability, but has a short running time, and the initial high torque of a fully wound motor drops sharply before plateauing to a steady output, until the final turns unwind and power drops off completely. Using it efficiently is one of the challenges of competitive free-flight rubber flying, and variable-pitch propellers, differential wing and tailplane incidence and rudder settings, controlled by timers, can help to manage the torque. There are also usually motor weight restrictions in contest classes. Even so, models have achieved flights of nearly 1 hour.
==== Compressed gases ====
Stored compressed gas, typically carbon dioxide (CO2), can power simple models in a manner similar to filling a balloon and then releasing it. Compressed CO2 may also be used to power an expansion engine to turn a propeller. These engines can incorporate speed controls and multiple cylinders, and are capable of powering lightweight scale radio-controlled aircraft. Gasparin and Modela are two recent makers of CO2 engines. CO2, like rubber, is known as "cold" power because it generates no heat.
Steam is even older than rubber power, and like rubber, contributed much to aviation history, but is now rarely used. In 1848, John Stringfellow flew a steam-powered model, in Chard, Somerset, England. Samuel Pierpont Langley built both steam- and internal-combustion-powered models that made long flights.
Baronet Sir George Cayley built, and flew, internal and external combustion gunpowder-fueled model aircraft engines in 1807, 1819, and 1850. These had no crank, working ornithopter-like flappers instead of a propeller. He speculated that the fuel might be too dangerous for manned aircraft.
==== Internal combustion ====
For larger and heavier models, the most popular powerplant is the glow plug engine. Glow engines are fueled by a mixture of slow burning methanol, nitromethane, and lubricant (castor oil or synthetic oil), which is sold pre-mixed as glow-fuel. Glow-engines require an external starting mechanism; the glow plug must be heated until it is hot enough to ignite fuel to start. Reciprocating cylinders apply torque to a rotating crankshaft, which is the engine's primary power-output. Some power is lost from converting linear motion to rotary and in lost heat and unburned fuel, so efficiency is low.
These are rated by engine displacement and range from 0.01 cu in (0.16 cc) to over 1.0 cu in (16 cc). The smallest engines can spin a 3.5 inches (8.9 cm) propeller to over 30,000 rpm, while the larger engines turn at 10–14,000 rpm.
The simplest glow-engines use the two-stroke cycle. These engines are inexpensive, and offer the highest power-to-weight ratio of all glow-engines, but are noisy and require substantial expansion chamber mufflers, which may be tuned. four-stroke cycle glow engines, whether using poppet valves or more rarely rotary valves are more fuel-efficient, but deliver less power than similar two-stroke engines. The power they deliver is more suited to turning larger diameter propellers for lighter weight, higher drag airframes such as with in biplanes. Four-stroke engines are now popular as they are quieter than two-stroke engines, and are available in horizontally opposed twins and radial engine configurations. Variations include engines with multiple-cylinders, spark-ignition gasoline operation, carbureted diesel operation and variable compression-ratio engines. Diesels are preferred for endurance and have higher torque, and for a given capacity, can "swing" a larger propeller than a glow engine. Home manufacture of model aircraft engines is a hobby in its own right.
==== Jets and rockets ====
Early "jet" style model aircraft used a multi-blade propeller ducted fan, inside ductwork, usually in the fuselage. The fans were generally powered by 2 stroke engines at high RPM. They generally had 0.40 to 0.90 cu in (6.6 to 14.7 cc) displacements, but some were as small as 0.049 cu in (0.80 cc). This fan-in-tube design has been adopted successfully for electric-powered jets while glow engine powered ducted-fan aircraft are now rare. Small jet turbine engines are now used in hobbyist models that resemble simplified versions of the turbojet engines found on commercial aircraft, but are not scaled-down as Reynolds numbers come into play. The first hobbyist-developed turbine was developed and flown in the 1980s but recently have commercial examples become readily available. Turbines require specialized design and precision-manufacturing, and some have been built from car engine turbocharger units. Owning or operating a turbine-powered aircraft is prohibitively expensive and many national clubs (as with the USA's Academy of Model Aeronautics) require members to be certified to safely use them.
V-1 flying bomb type Pulsejet engines have also been used as they offer more thrust in a smaller package than a traditional glow-engine, but are not widely used due to the extremely high noise levels they produce, and are illegal in some countries.
Rocket engines are sometimes used to boost gliders and sailplanes. The earliest purpose-built rocket motor dates back to the 1950s, with the introduction of the Jetex motor, which used solid fuel pellets, ignited by a wick fuse, in a reusable casing. Flyers can now also use single-use model rocket engines to provide a short, under 10 second burst of power. Government restrictions in some countries made rocket-propulsion rare but these were being eased in many places and their use was expanding, however a reclassification from "smoke producing devices" to "fireworks" has made them difficult to obtain again.
==== Electric power ====
Electric-powered models use an electric motor powered by a source of electricity - usually a battery. Electrical power began being used on models in the 1970s, but the cost delayed widespread use until the early 1990s, when more efficient battery technologies, and brushless motors became available, while the costs of motors, batteries and control systems dropped dramatically. Electric power now predominated with park-flyer and 3D-flyer models, both of which are small and light, where electric-power offers greater efficiency and reliability, less maintenance and mess, quieter flight and near-instantaneous throttle response compared to internal combustion engines.
The first electric models used brushed DC motors and nickel cadmium (NiCad) rechargeable cells that gave flight times of 5 to 10 minutes, while a comparable glow-engine provided double the flight-time. Later electric systems used more-efficient brushless DC motors and higher-capacity nickel metal hydride (NiMh) batteries, yielding considerably improved flight times. Cobalt and lithium polymer batteries (LiPoly or LiPo) permit electric flight-times to surpass those of glow-engines, while the more rugged and durable, cobalt-free lithium iron phosphate batteries are also becoming popular. Solar power has also become practical for R/C hobbyists, and in June 2005 a record flight of 48 hours and 16 minutes was set in California. It is now possible to power most models under 20 lb (9.1 kg) with electric power for a cost equivalent to or lower than traditional power sources.
Recent developments have resulted in the use of brushless three-phase motors in model aviation. Brushless motors are more powerful and offer greater torque and efficiency. The design of brushless motors also means less internal friction, as there is no requirement for brushes to be in contact with any rotating parts. This increase in efficiency results in longer flight times.
=== Propulsion types ===
Most powered model-aircraft, including electric, internal-combustion, and rubber-band powered models, generate thrust by spinning an airscrew. The propeller is the most commonly used device. Propellers generate thrust due to lift generated by the wing-like sections of the blades, which forces air backward.
==== Propellers ====
A large diameter and low-pitch propeller offers greater thrust and acceleration at low airspeed, while a small diameter and higher-pitch propeller sacrifices acceleration for higher maximum speeds. The builder can choose from a selection of propellers to match the model but a mismatched propeller can compromise performance, and if too heavy, cause undue wear on the powerplant. Model aircraft propellers are usually specified as diameter × pitch, in inches. For example, a 5 x 3 propeller has a diameter of 5 inches (130 mm), and a pitch of 3 inches (76 mm). The pitch is the distance that the propeller would advance if turned through one revolution in a solid medium. Two and three bladed propellers are the most common.
Three methods are used to transfer energy to the propeller:
Direct-drive systems have the propeller attached directly to the engine's crankshaft or driveshaft. This arrangement is preferred when the propeller and powerplant both operate near peak efficiency at similar rpms. Direct-drive is most common with fuel-powered engines. Rarely, some electric motors are designed with a sufficiently high torque and low enough speed and can utilize direct-drive as well. These motors are typically called outrunners.
Reduction drive uses gears to reduce shaft rpm, so the motor can spin much faster. The higher the gear ratio, the slower the prop rotates, which also increases torque by roughly the same ratio. This is common on larger models and on those with unusually large propellers. The reduction drive matches the powerplant and propeller to their respective optimum operating speeds. Geared propellers are rare on internal combustion engines, but are common on electric motors because most electric motors spin extremely fast, but lack torque.
A built-in 2:1 gear reduction ratio can be obtained by attaching the propeller to the camshaft rather than the crankshaft of a four stroke engine, which runs at half the speed of the crankshaft.
==== Ducted fans ====
Ducted fans are multi-blade propellers encased in a cylindrical duct or tube that may look like and fit in the same space as jet engine. They are available for both electric and liquid-fuelled engines, although they have become common with recent improvements in electric-flight technology. A model aircraft can now be fitted with four electric ducted fans for less than the cost of a single jet turbine, enabling affordable modelling of multi-engine airplanes. Compared to an unducted propeller, a ducted fan generates more thrust for the same area and speeds of up to 200 mph (320 km/h) have been recorded with electric-powered ducted fan airplanes, largely due to the higher RPMs possible with ducted fan propellers. Ducted fans are popular with scale models of jet aircraft, where they mimic the appearance of jet engines but they are also found on non-scale and sport models, and even lightweight 3D-flyers.
==== Other ====
With ornithopters the motion of the wing structure imitates the flapping-wings of living birds, producing both thrust and lift.
== Competitions and classes ==
World competitions are organized by the Fédération Aéronautique Internationale (FAI) in many classes, groups, and subclasses:
Class F – model aircraft
F1x – Free Flight
F2x – Control Line
F3x – Radio Control
F4x – Scale Aircraft (a reduced-size reproduction of a full-size aircraft)
F5x – Radio Control Electric Powered Motor Gliders
FAI – Drone Racing (F3U)
Class S – space model
Class U – unmanned aerial vehicle
=== Free flight (F1) ===
The Wakefield Gold Challenge Cup is an international modelling competition named for the donor, Lord Wakefield. The event was first held on 5 July 1911 at The Crystal Palace in England. There were contests in 1912, 1913 and 1914. No contests were held again until 1927, when the Society of Model Aeronautical Engineers (SMAE) approached Lord Wakefield for a new larger silver trophy for international competition. This trophy is the present Wakefield International Cup and was first awarded in 1928. The SMAE organized the international competitions until 1951 when the FAI took over, and has since been made the award for the rubber-power category at the FAI World Free Flight Championships.
The FAI free flight classes include:
F1A – Gliders
F1B – Model Aircraft with extensible (rubber band) motors – Wakefield Trophy
F1C – Power model aircraft (combustion powered 2.5 cc (0.15 cu in))
F1D – Indoor model aircraft
F1E – Gliders with automatic steering
F1N – Indoor hand-launch gliders
F1P – Power model aircraft (combustion powered 1.0cc)
F1Q – Electric power model aircraft
F1G – Model aircraft with extensible (rubber band) motors « Coupe d’hiver » (provisional)
F1H – Gliders (provisional)
F1J – Power model aircraft (provisional) (combustion powered 1.0 cc (0.061 cu in))
F1K – Model aircraft with CO2 motors (provisional)
F1L – Indoor zone EZB model aircraft (provisional)
F1M – Indoor model aircraft (provisional)
F1R – Indoor model aircraft “Micro 35” (provisional)
F1S – Small electric power model aircraft “E36”
=== Control line (F2) ===
Also referred to as U-Control in the US, it was pioneered by the late Jim Walker who often, for show, flew three models at a time. Normally the model is flown in a circle and controlled by a pilot in the center holding a handle connected to two thin steel wires. The wires connect through the inboard wing tip of the plane to a mechanism that translates the handle movement to the aircraft elevator, allowing maneuvers to be performed along the aircraft pitch axis. The pilot turns to follow the model going round, the convention being counterclockwise for upright level flight.
For the conventional control-line system, tension in the lines is required to provide control. Line tension is maintained largely by centrifugal force. To increase line tension, models may be built or adjusted in various ways. Rudder offset and thrust vectoring (tilting the engine toward the outside) yaw the model outward. The position where the lines exit the wing can compensate for the tendency of the aerodynamic drag of the lines to yaw the model inboard. Weight on the outside wing, an inside wing that is longer or has more lift than the outside wing (or even no outside wing at all) and the torque of a left rotating propeller (or flying clockwise) tend to roll the model toward the outside. Wing tip weights, propeller torque, and thrust vectoring are more effective when the model is going slowly, while rudder offset and other aerodynamic effects have more influence on a fast moving model.
Since its introduction, control line flying has developed into a competition sport. There are contest categories for control line models, including Speed, Aerobatics (AKA Stunt), Racing, Navy Carrier, Balloon Bust, Scale, and Combat. There are variations on the basic events, including divisions by engine size and type, skill categories, and age of model design.
The events originated largely in the United States, and were later adapted for use internationally. The rules for US Competition are available from the Academy of Model Aeronautics. The international rules are defined by the Fédération Aéronautique Internationale (FAI). World Championships are held semiannually throughout the world, most recently in 2008 in France, with a limited slate of events – special varieties of Racing (F2C or "Team Race"), combat (F2D), and speed (F2A), all limited to engines displacing 0.15 cu. in (2.5cc), and Stunt (F2b), which is essentially unlimited with regard to design and size.
CIAM (FAI Aeromodelling Commission) designated the following classes in the F2 Control Line category:
F2A
CL Speed
F2B
CL Aerobatics
F2C
CL Team racing
The international class of racing is referred to as F2C (F2 = Control-line, C=racing) or Team Race. A pilot and a mechanic compete as a team to fly small 370 g (13 oz) 65 cm (26 in) wingspan semi-scale racing models over a tarmac or concrete surface. Lines are 15.92 m (52.2 ft) long.
Three pilots, plus mechanic teams, compete simultaneously in the same circle, and the object is to finish the determined course as fast as possible. Tank size is limited to 7 cc (0.43 cu in), requiring 2 or 3 refueling pitstops during the race.
The mechanic stands at a pit area outside the marked flight circle. The engine is started and the model released on the start signal. For refueling, the pilot operates a fuel shutoff by a quick down elevator movement after the planned number of laps so that the model can approach the mechanic at optimum speed, of around 31 mph (50 km/h). The mechanic catches the model by the wing, fill the tank from a pressurized can by a hose and finger valve, then restart the engine by flicking the propeller with his finger. A pitstop generally takes less than three seconds.
The course is 6.2 mi (10 km), with 100 laps. Flying speeds are around 200 km/h (120 mph), which means that the pilots turn one lap in roughly 1.8 seconds. Line pull due to centrifugal force is 19 lbf (85 N). An overtaking model is steered over the heads of the competing pilots of slower models.
After two rounds of elimination heats, the 6, 9 or 12 fastest teams enter two semifinal rounds, and the three fastest teams in the semifinals go to the final, which is run over the double course. Single cylinder two-stroke Diesel compression ignition engines designed for this purpose of up to 2.5 cc (0.15 cu in) are used. At the world championship level it is common for competitors design and build their own engines. Output power approaches 0.8 hp (0.60 kW) at 25,000 rpm.
==== F2D – control line combat ====
CLASS F2D - Control Line Combat Model Aircraft - Two pilots compete, with four mechanics in the pit. The aircraft are light and stubby so as to maneuver quickly in the air. Each has a 8 ft 2 in (2.5 m) crepe paper streamer attached to the rear of the aircraft by a 3 m (9.8 ft) string. Each pilot attacks only the other aircraft's streamer, to attempt to cut it with their propeller or wing. Each cut scores 100 points. Each second the model is in the air scores a point and the match runs for 4 minutes from the starter's signal. At the almost 120 mph (200 km/h) speeds of the aircraft, mistakes often lead to crash damage so two aircraft are permitted for each match. The mechanics are prepared for crashes and quickly start the second aircraft and transfer the streamer to the reserve model before launching. The action is so fast that an observer may miss the cuts of the streamers. A second loss eliminates a competitor, and the last pilot still flying wins.
=== Radio-controlled flight (F3) ===
The FAI radio control classes include:
F3A
RC Aerobatic Aircraft
F3B
RC Multi-Task Gliders
F3C
RC Aerobatic Helicopters
F3D
RC Pylon Racing Aeroplanes – Pylon racing refers to a class of air racing for radio controlled model aircraft that fly through a course of pylons. The sport is similar to the full-scale Red Bull Air Race World Series.
F3F
RC Slope Soaring Gliders
F3J
RC Thermal Duration Gliders
F3K
RC Hand Launch Gliders
F3M
RC Large Aerobatic Aircraft
F3N
RC Freestyle Aerobatic Helicopters
F3P
RC Indoor Aerobatic Aircraft
F3H
RC Soaring Cross Country Gliders
F3Q
RC Aero-Tow Gliders
F3R
RC Pylon Racing Limited Technology Aeroplanes
F3S
RC Jet Aerobatic Aircraft
F3T
RC Semi-Scale Pylon Racing with Controlled Technology Aeroplanes
F3U
RC Multi-rotor FPV Racing – The FAI Drone Racing World Cup is in the F3U class (Radio Control Multi-rotor FPV Racing). This is a highly competitive drone racing activity, involving mental exertion and big cash prizes.
=== Scale aircraft (F4) ===
The FAI classes for scale model aircraft (a reduced-size reproduction of a full-size aircraft) include:
F4B
control line scale aeroplanes
F4C
radio control scale aeroplanes
F4H
radio control stand-off scale aeroplanes
=== Radio-controlled electric motor gliders (F5) ===
The FAI classes include:
F5B – Electric Motor Glider – Multi Task (held in alternate years only)
F5D – Electric Pylon Racing
F5J – Electric Motor Glider – Thermal Duration
== Model aerodynamics ==
The flight behavior of an aircraft depends on the scale to which it is built, the density of the air and the speed of flight.
At subsonic speeds the relationship between these is expressed by the Reynolds number. Where two models at different scales are flown with the same Reynolds number, the airflow is similar. Where the Reynolds numbers differ, as for example a small-scale model flying at lower speed than the full-size craft, the airflow characteristics can differ significantly. This can make an exact scale model unflyable, and the model has to be modified in some way. For example, at low Reynolds numbers, a flying scale model usually requires a larger-than-scale propeller.
Maneuverability depends on scale, with stability also becoming more important. Control torque is proportional to lever arm length while angular inertia is proportional to the square of the lever arm, so the smaller the scale the more quickly an aircraft or other vehicle turns in response to control inputs or outside forces.
One consequence of this is that models in general require additional longitudinal and directional stability, resisting sudden changes in pitch and yaw. While it may be possible for a pilot to respond quickly enough to control an unstable aircraft, a radio control scale model of the same aircraft would be flyable only with design adjustments such as increased tail surfaces and wing dihedral for stability, or with avionics providing artificial stability. Free flight models need to have both static and dynamic stability. Static stability is the resistance to sudden changes in pitch and yaw already described, and is typically provided by the horizontal and vertical tail surfaces respectively, and by a forward center of gravity. Dynamic stability is the ability to return to straight and level flight without any control input. The three dynamic instability modes are pitch (phugoid) oscillation, spiral and Dutch roll. An aircraft with too large a horizontal tail on a fuselage that is too short may have a phugoid instability with increasing climbs and dives. With free flight models, this usually results in a stall or loop at the end of the initial climb. Insufficient dihedral or sweep back generally leads to increasing spiral turn. Too much dihedral or sweepback generally causes Dutch roll. These all depend on the scale, as well as details of the shape and weight distribution. For example, the paper glider shown here is a contest winner when made of a small sheet of paper but goes from side to side in Dutch roll when scaled up even slightly.
== See also ==
== Footnotes ==
== References ==
RCadvisor′s Model Airplane Design Made Easy, by Carlos Reyes, RCadvisor.com, Albuquerque, New Mexico, 2009. ISBN 9780982261323 OCLC 361461928
The Great International Paper Airplane Book, by Jerry Mander, George Dippel and Howard Gossage, Simon and Schuster, New York, 1967. ISBN 0671289918 OCLC 437094
Model Aircraft Aerodynamics, by Martin Simons, Swanley: Nexus Special Interests, 1999. 4th ed. ISBN 1854861905 OCLC 43634314
How to Design and Build Flying Model Airplanes, by Keith Laumer, Harper, New York, 1960. 2nd ed., 1970. OCLC 95315
The Middle Ages of the Internal-Combustion Engine, by Horst O. Hardenberg, SAE, 1999. ISBN 0768003911 OCLC 40632327
Model Airplane Design and Theory of Flight, by Charles Hampson Grant, Jay Publishing Corporation, New York, 1941. OCLC 1336984
Pulling Back the Clouds, by Mike Kelly, Limerick Writers' Centre Publishing, Ireland, 2020. ISBN 9781916065383 | Wikipedia/Aeromodeling |
In 3D computer graphics, 3D modeling is the process of developing a mathematical coordinate-based representation of a surface of an object (inanimate or living) in three dimensions via specialized software by manipulating edges, vertices, and polygons in a simulated 3D space.
Three-dimensional (3D) models represent a physical body using a collection of points in 3D space, connected by various geometric entities such as triangles, lines, curved surfaces, etc. Being a collection of data (points and other information), 3D models can be created manually, algorithmically (procedural modeling), or by scanning. Their surfaces may be further defined with texture mapping.
== Outline ==
The product is called a 3D model, while someone who works with 3D models may be referred to as a 3D artist or a 3D modeler.
A 3D model can also be displayed as a two-dimensional image through a process called 3D rendering or used in a computer simulation of physical phenomena.
3D models may be created automatically or manually. The manual modeling process of preparing geometric data for 3D computer graphics is similar to plastic arts such as sculpting. The 3D model can be physically created using 3D printing devices that form 2D layers of the model with three-dimensional material, one layer at a time. Without a 3D model, a 3D print is not possible.
3D modeling software is a class of 3D computer graphics software used to produce 3D models. Individual programs of this class are called modeling applications.
== History ==
3D models are now widely used anywhere in 3D graphics and CAD but their history predates the widespread use of 3D graphics on personal computers.
In the past, many computer games used pre-rendered images of 3D models as sprites before computers could render them in real-time. The designer can then see the model in various directions and views, this can help the designer see if the object is created as intended to compared to their original vision. Seeing the design this way can help the designer or company figure out changes or improvements needed to the product.
=== Representation ===
Almost all 3D models can be divided into two categories:
Solid – These models define the volume of the object they represent (like a rock). Solid models are mostly used for engineering and medical simulations, and are usually built with constructive solid geometry
Shell or boundary – These models represent the surface, i.e., the boundary of the object, not its volume (like an infinitesimally thin eggshell). Almost all visual models used in games and film are shell models.
Solid and shell modeling can create functionally identical objects. Differences between them are mostly variations in the way they are created and edited and conventions of use in various fields and differences in types of approximations between the model and reality.
Shell models must be manifold (having no holes or cracks in the shell) to be meaningful as a real object. In a shell model of a cube, the bottom and top surfaces of the cube must have a uniform thickness with no holes or cracks in the first and last layers printed. Polygonal meshes (and to a lesser extent, subdivision surfaces) are by far the most common representation. Level sets are a useful representation for deforming surfaces that undergo many topological changes, such as fluids.
The process of transforming representations of objects, such as the middle point coordinate of a sphere and a point on its circumference, into a polygon representation of a sphere is called tessellation. This step is used in polygon-based rendering, where objects are broken down from abstract representations ("primitives") such as spheres, cones etc., to so-called meshes, which are nets of interconnected triangles. Meshes of triangles (instead of e.g., squares) are popular as they have proven to be easy to rasterize (the surface described by each triangle is planar, so the projection is always convex). Polygon representations are not used in all rendering techniques, and in these cases the tessellation step is not included in the transition from abstract representation to rendered scene.
== Process ==
There are three popular ways to represent a model:
Polygonal modeling – Points in 3D space, called vertices, are connected by line segments to form a polygon mesh. The vast majority of 3D models today are built as textured polygonal models because they are flexible and because computers can render them so quickly. However, polygons are planar and can only approximate curved surfaces using many polygons.
Curve modeling – Surfaces are defined by curves, which are influenced by weighted control points. The curve follows (but does not necessarily interpolate) the points. Increasing the weight for a point pulls the curve closer to that point. Curve types include nonuniform rational B-spline (NURBS), splines, patches, and geometric primitives
Digital sculpting – There are three types of digital sculpting: Displacement, which is the most widely used among applications at this moment, uses a dense model (often generated by subdivision surfaces of a polygon control mesh) and stores new locations for the vertex positions through use of an image map that stores the adjusted locations. Volumetric, loosely based on voxels, has similar capabilities as displacement but does not suffer from polygon stretching when there are not enough polygons in a region to achieve a deformation. Dynamic tessellation, which is similar to voxel, divides the surface using triangulation to maintain a smooth surface and allow finer details. These methods allow for artistic exploration as the model has new topology created over it once the models form and possibly details have been sculpted. The new mesh usually has the original high-resolution mesh information transferred into displacement data or normal map data if it is for a game engine.
The modeling stage consists of shaping individual objects that are later used in the scene. There are a number of modeling techniques, including:
Constructive solid geometry
Implicit surfaces
Subdivision surfaces
Modeling can be performed by means of a dedicated program (e.g., 3D modeling software like Adobe Substance, Blender, Cinema 4D, LightWave, Maya, Modo, 3ds Max, SketchUp, Rhinoceros 3D, and others) or an application component (Shaper, Lofter in 3ds Max) or some scene description language (as in POV-Ray). In some cases, there is no strict distinction between these phases; in such cases, modeling is just part of the scene creation process (this is the case, for example, with Caligari trueSpace and Realsoft 3D).
3D models can also be created using the technique of Photogrammetry with dedicated programs such as RealityCapture, Metashape and 3DF Zephyr. Cleanup and further processing can be performed with applications such as MeshLab, the GigaMesh Software Framework, netfabb or MeshMixer. Photogrammetry creates models using algorithms to interpret the shape and texture of real-world objects and environments based on photographs taken from many angles of the subject.
Complex materials such as blowing sand, clouds, and liquid sprays are modeled with particle systems, and are a mass of 3D coordinates which have either points, polygons, texture splats or sprites assigned to them.
== 3D modeling software ==
There are a variety of 3D modeling programs that can be used in the industries of engineering, interior design, film and others. Each 3D modeling software has specific capabilities and can be utilized to fulfill demands for the industry.
=== G-code ===
Many programs include export options to form a g-code, applicable to additive or subtractive manufacturing machinery. G-code (computer numerical control) works with automated technology to form a real-world rendition of 3D models. This code is a specific set of instructions to carry out steps of a product's manufacturing.
=== Human models ===
The first widely available commercial application of human virtual models appeared in 1998 on the Lands' End web site. The human virtual models were created by the company My Virtual Mode Inc. and enabled users to create a model of themselves and try on 3D clothing. There are several modern programs that allow for the creation of virtual human models (Poser being one example).
=== 3D clothing ===
The development of cloth simulation software such as Marvelous Designer, CLO3D and Optitex, has enabled artists and fashion designers to model dynamic 3D clothing on the computer.
Dynamic 3D clothing is used for virtual fashion catalogs, as well as for dressing 3D characters for video games, 3D animation movies, for digital doubles in movies, as a creation tool for digital fashion brands, as well as for making clothes for avatars in virtual worlds such as SecondLife.
== Comparison with 2D methods ==
3D photorealistic effects are often achieved without wire-frame modeling and are sometimes indistinguishable in the final form. Some graphic art software includes filters that can be applied to 2D vector graphics or 2D raster graphics on transparent layers.
Advantages of wireframe 3D modeling over exclusively 2D methods include:
Flexibility, ability to change angles or animate images with quicker rendering of the changes;
Ease of rendering, automatic calculation and rendering photorealistic effects rather than mentally visualizing or estimating;
Accurate photorealism, less chance of human error in misplacing, overdoing, or forgetting to include a visual effect.
Disadvantages compared to 2D photorealistic rendering may include a software learning curve and difficulty achieving certain photorealistic effects. Some photorealistic effects may be achieved with special rendering filters included in the 3D modeling software. For the best of both worlds, some artists use a combination of 3D modeling followed by editing the 2D computer-rendered images from the 3D model.
== 3D model market ==
A large market for 3D models (as well as 3D-related content, such as textures, scripts, etc.) exists—either for individual models or large collections. Several online marketplaces for 3D content allow individual artists to sell content that they have created, including TurboSquid, MyMiniFactory, Sketchfab, CGTrader, and Cults. Often, the artists' goal is to get additional value out of assets they have previously created for projects. By doing so, artists can earn more money out of their old content, and companies can save money by buying pre-made models instead of paying an employee to create one from scratch. These marketplaces typically split the sale between themselves and the artist that created the asset, artists get 40% to 95% of the sales according to the marketplace. In most cases, the artist retains ownership of the 3d model while the customer only buys the right to use and present the model. Some artists sell their products directly in their own stores, offering their products at a lower price by not using intermediaries.
The architecture, engineering and construction (AEC) industry is the biggest market for 3D modeling, with an estimated value of $12.13 billion by 2028. This is due to the increasing adoption of 3D modeling in the AEC industry, which helps to improve design accuracy, reduce errors and omissions and facilitate collaboration among project stakeholders.
Over the last several years numerous marketplaces specializing in 3D rendering and printing models have emerged. Some of the 3D printing marketplaces are a combination of models sharing sites, with or without a built in e-com capability. Some of those platforms also offer 3D printing services on demand, software for model rendering and dynamic viewing of items.
== 3D printing ==
The term 3D printing or three-dimensional printing is a form of additive manufacturing technology where a three-dimensional object is created from successive layers of material. Objects can be created without the need for complex expensive molds or assembly with multiple parts. 3D printing allows ideas to be prototyped and tested without having to go through a production process.
3D models can be purchased from online markets and printed by individuals or companies using commercially available 3D printers, enabling the home-production of objects such as spare parts and even medical equipment.
== Uses ==
3D modeling is used in many industries.
The medical industry uses detailed models of organs created from multiple two-dimensional image slices from an MRI or CT scan. Other scientific fields can use 3D models to visualize and communicate information such as models of chemical compounds.
The movie industry uses 3D models for computer-generated characters and objects in animated and real-life motion pictures. Similarly, the video game industry uses 3D models as assets for computer and video games. The source of the geometry for the shape of an object can be a designer, industrial engineer, or artist using a 3D CAD system; an existing object that has been reverse engineered or copied using a 3D shape digitizer or scanner; or mathematical data based on a numerical description or calculation of the object.
The architecture industry uses 3D models to demonstrate proposed buildings and landscapes in lieu of traditional, physical architectural models. Additionally, the use of Level of Detail (LOD) in 3D models is becoming increasingly important in architecture, engineering, and construction.
Archeologists create 3D models of cultural heritage items for research and visualization. For example, the International Institute of MetaNumismatics (INIMEN) studies the applications of 3D modeling for the digitization and preservation of numismatic artifacts.
In recent decades, the earth science community has started to construct 3D geological models as a standard practice.
3D models are also used in constructing digital representations of mechanical parts before they are manufactured. Using CAD- and CAM-related software, an engineer can test the functionality of assemblies of parts then use the same data to create toolpaths for CNC machining or 3D printing.
3D modeling is used in industrial design, wherein products are 3D modeled before representing them to the clients.
In media and event industries, 3D modeling is used in stage and set design.
The OWL 2 translation of the vocabulary of X3D can be used to provide semantic descriptions for 3D models, which is suitable for indexing and retrieval of 3D models by features such as geometry, dimensions, material, texture, diffuse reflection, transmission spectra, transparency, reflectivity, opalescence, glazes, varnishes and enamels (as opposed to unstructured textual descriptions or 2.5D virtual museums and exhibitions using Google Street View on Google Arts & Culture, for example). The RDF representation of 3D models can be used in reasoning, which enables intelligent 3D applications which, for example, can automatically compare two 3D models by volume.
== See also ==
== References ==
== External links ==
Media related to 3D modeling at Wikimedia Commons | Wikipedia/Modeler |
Brass models are scale models typically of railroad equipment, bridges and occasionally of buildings, made from brass or similar alloys. Although die-cast or plastic models have made considerable advances in late 1990s and continue to improve, brass models offer finer details. Brass models, considered to be collector's pieces and museum quality finish, are often used for display purposes rather than model railroad operations. However, these can be made fully operational and many railroaders do use them on their model railroads. They are generally considerably more expensive than other types of models due to limited production quantities and the "handmade" nature of the product itself.
== History ==
In the late 1950s, Japan was known for producing low cost toys and products for export. The first brass model trains were created during the occupation of Japan by Allied forces. Members of allied forces saw some of the models built by various craftsman and procured photos of American steam locomotive prototypes for these artisans to model. These were the early hand-built high quality brass models, built with relatively crude equipment in comparison to tools that became available later. Some people in the model railroad industry took note of what was being done and started importing these models to the United States. The scale of import increased with time. Bill Ryan of PFM (Pacific Fast Mail) was one of the early importers, and to this day the name PFM is synonymous with brass model trains.
The quality of Japanese models continued to improve but with an improving domestic economy, manufacturing cost also increased. Eventually, importers moved their operations to Korea for cost benefits. Although the quality suffered considerably in the early years of this transition, within a few years some very fine brass models were being built.
Thousands of brass model trains have been produced throughout the years. Initially their price was comparable to that of die-cast models, but the detail was far superior. The quality and details of brass models have increased with time along with its price. As of 2014, an articulated HO scale, highly detailed model may retail for as much as US $3000; larger scales can cost even more. The collectibility of late run highly detailed models, along with lower availability, generally keeps the prices high. Historically, the most desirable models have continued to rise in value. Mid-run (1960-1985) models, in particular unpainted models, have appeared to drop in value lately, as they are becoming less desirable in comparison with newer models with much better details. These models still often sell for several times the original suggested retail price.
== Glossary ==
Glossary of brass model train terminology:
Handbuilt
Generally refers to the early models made for the GIs that were built entirely by hand. In many ways brass models are still handbuilt to this day.
Crown
At first these were very limited runs of the highest quality models imported by PFM. Later the term was used a bit more loosely, though generally only for very high quality models. Other importers used phrases such as 'Ruby' (Gem Models), 'Royale Series' (Custom Brass), or something similar.
Factory Painted
A model painted by the builder. Some models were painted in the USA after being imported. Though these paint jobs were commissioned by the importer and are normally high quality, they would be considered custom painted.
Custom Paint
This has a broad meaning, as the quality can vary widely; however, it means any model that is painted, but not by the builder.
Pro Paint
This term should only be used by professional painters. The quality of a true professional should be very close to that of a factory painted model.
Plated
A term for nickel plating; often brass drivers (wheels) are nickel-plated, silver color. At times entire models are nickel-plated (they look like silver).
Wheel Wear
This refers to brass showing through on the drivers (wheels). This happens when the engine has been run enough on a track to wear through the nickel plating, and often is a sign of somewhat heavy use of the model.
Drawbar
The bar that connects a steam locomotive to the tender. Often needed for a good electrical connection.
Open Frame Motor
Used on earlier models, generally up until the early 1970s. You can see the armature, brushes on the sides of the motor.
Can Motor
A more desirable motor, as it generally offers more power, and needs less maintenance. The motor is enclosed in a 'can', and the brushes cannot be seen.
== Manufacturers ==
Manufacturers of brass models include:
Bavaria
Boo-Rim Precision
Ajin Precision
Fulgurex
Lemaco
Musashino Model
Active Importers, both in the USA and Europe include:
Precision Scale Models, Inc
Glacier Park Models
The Coach Yard
Union Terminal Imports
North Bank Line
Micro Metakit
Overland Models Inc.
Key Model Imports
Sunset Models, 3rd Rail
Importers that are no longer active include:
Railway Classics
Shoreham Shops
W&R Enterprises
Weinert
Classic Construction Models
Max Gray
Pacific Fast Mail
WestSide Model Company
Ferro Swiss
KTM
NJ International, Custom Brass
E.Suydam & Company
Tenshodo
Von Stetina Artworks
EFC-Loko
TOLOLOKO
== See also ==
Rail transport modelling
Scale models
HO scale
== References ==
== External links ==
The Brass Train Guide Book (http://www.brasstrains.com/Classic/Product/Detail/030010/The-Brass-Train-Guide-Book-Deluxe-Edition)
Brass Model Trains Price & Data Guide Volume 2 (http://www.brasstrains.com/Classic/Product/Detail/030003/Brass-Model-Trains-Price-Data-Guide-Volume-2)
Online Brass Guide LIVE (www.brassguide.com)
Brass Department | Wikipedia/Brass_model |
Modelguns are Japanese replica or toy guns which are usually made of zinc alloys or plastic materials. Most modelguns commonly available today are designed to highly replicate the physical appearance (some bear the authentic trademarks and markings too) and in full scale of the real gun counterpart. Many are even made to highly replicate the internal mechanisms so that they are able to strip-down exactly and imitate closely the functionalities of the real counterparts. They operate exactly like a cap gun, using a small plastic percussion cap to produce gunfire sound, spark and blowback operation (for automatic models), but strictly not able to shoot any projectile.
There are very strict gun control laws in Japan to restrict the mechanisms and material of modelguns so that modelguns appearing in the Japanese market are safe and cannot be converted into anything that can shoot live cartridges or projectiles. Their high resemblance to the real guns and complete safeness make them very attractive to many gun enthusiasts, especially in those countries with very strict gun control. Best of all, they are only a fraction of cost to the real ones and some even replicate the very rare out-of-reach original models. Modelguns are legal to own in many countries and don't require license for ownership. Having said that, it is recommended that the respective law regarding imitated firearms of individual country should be consulted. Modelguns are not illegal in some countries but it is very hard to pass their Customs. Whilst they are free to import and own in some other countries but the cap is illegal to sell and own there. They may also have trademark infringement issues in some countries.
Besides private collection by hobbyists, they are often used in movie production, re-enactment, authority training and museum display purposes. On the other hand, even airsoft guns look very close to the real guns, their internal design is very different from the respective real ones. Therefore, airsoft guns are generally not regarded as modelguns.
== History ==
Modelguns were developed after the Second World War due to tight restrictions on firearm ownership by civilians in Japan. As a result, toy guns became popular with many Japanese gun enthusiasts. The early toy guns were imported cap guns (mainly Mattel, Hubley and Nichols) from the United States from late 1950s. Some of the agencies or shops notably Japan Model Gun Collection Association (later MGC), Nakata store, Ehara store (later Tokyo CMC), International Gun Club (later International Industry (Kokusai)) importing or retailing the cap guns later transformed to key modelgun makers and played a key role in modelgun history. These cap guns were fairly crude approximations of actual firearms and with very few operational features. Strictly speaking they are not classified as modelguns as their design / markings and even size is very different from the real counterparts. Nevertheless, these imported cap guns formed the foundation for further modelgun development and gave designers insight for producing new modelgun designs in Japan.
From 1960, the retail shops / import agencies started some modifications (e.g. surface finish from silver to black color) on the imported cap guns locally to make them more realistic and attractive. In 1960–61, MGC (ModelGuns Corporation) released modified Mattel Snub Nose and Hubley Automatic (from a normal cap gun to a cartridge ejection model) which is one step closer to Japanese originated modelgun.
The imported cap guns were eventually replaced with more realistic Japanese indigenous designed and elegantly produced modelguns. The first Japanese designed modelgun is believed to be the Mauser Military Model M1896 (non-ignition model) released by Yamada Plating Industry (later Hudson Industry) in late 1962. Shortly after, MGC released the Walther VP-2 (ignition model with an innovative Slide action design) in early 1963. While there is still no unanimous consensus on the first Japanese modelgun, these 2 models are unarguably one of the pioneers in modelgun history.
In the next 2–3 years, MGC added some more models to its product line and sold its modelguns in bulk to other re-seller companies who sold them under individual brand names. In 1965, MGC started to sell its products in its own shop "MGC Bondshop". Meanwhile, 7 re-seller companies notably Nakata, Tokyo CMC, Hudson, Kokusai, and Malugo formed an allied association Nippon Kokyu Gangu Kumiai (NKG) or Japan Premium Toy Retailers' Union and stopped buying products from MGC. In 1966, the NKG member companies started to compete directly with MGC starting with non-movable paperweight models (mainly by Nakata, but strictly speaking not modelguns) and shortly later some copied MGC products by some NKG members. The competition heat was intensified when NKG members also had their own design of models which were produced by a modelgun manufacturing company Tokyo Replica Corp. (TRC) formed by Marushin Die Casting Industry and Nakata as a joint venture. After that, the modelgun industry boomed and its popularity grew tremendously. The first major change in the Firearms and Swords Law in 1971 did not have much impact to the growth trend.
Before 1977, metal modelguns dominated the market and plastic models were not popular. These early produced full metal modelguns are now sought-after collectables even though they are a bit less precise and detailed as real ones. After 1977 when the second change in the law started to heavily regulate the products, plastic modelguns led the market as only very limited handgun models can be made in full metal.
From 1970 to end-80s, many modelguns (mostly from MGC) were exported to the USA and sold under the RMI brand by Replica Models, Inc. (which later transformed to Collector's Armoury, Ltd.). These exported modelgun products were exempted from the strict Japanese Firearms and Swords Law.
As time went by, modelguns were enhanced technically with more realistic appearance, detailed construction and operation more accurate to real guns due to continuous competition among makers.
However, the roll-out of more Airsoft in the mid-80s has had a big impact to the traditional modelgun industry. The continuous fall in popularity and sales volume of modelguns in the next 30 years forced some modelgun makers either out of business or switching to mainly Airsoft production.
== Legends ==
The Japanese modelgun/Airsoft inventor Tanio Kobayashi (小林太三) is considered by many Japanese to be the "father" of the modelgun. He joined MGC as a chief engineer in 1961. Kobayashi's innovative internal modelgun design (known as Tanio or Slide action which makes the slide cycle to load and eject the cartridge when the trigger is pulled) in MGC Walther VP-2 completely revolutionized the simple cap gun design and led to the modern version of the modelgun. He also led MGC to innovate the safety barrel insert, the cap blowback system and the development of a safe plastic cap exclusively for modelguns. In 1978, The Ministry of International Trade and Industry (MITI) awarded Kobayashi (then Director of Design and Development Division of MGC) Honorable Prize for the development of safe modelgun design, construction method and contribution to the development of the modelgun industry. He left MGC and established his company Tanio Koba in 1992. His company continues to produce quality Airsoft and modelguns today.
Noboru Mutobe (六人部登) is a very important and highly reputable modelgun designer. He was a craft-worker and joined Nakata in 1962 to design and prototype modelguns for Nakata. His ingeniously designed and prototyped models that were produced by Nakata and later TRC were very competitive with the MGC products. He left Nakata in 1967 and established his own company Rokuken with products in the Rocken brand. Many of the Rocken modelguns which were made in solid brass are also known as high grade luxury models. But the metal modelgun production from Rokuken ceased after the amendment of the Firearms and Swords law in 1977. The Rocken brand metal modelguns were only produced in very small quantity and they are now expensive sought-after collectables. However, Rocken brand and designed high grade plastic modelguns were released by other makers from mid 90s and are still produced today. Mutobe also worked as an independent freelance designer to design and prototype many products for other modelgun companies such as CMC, Suzuki, Asahi Toys. His work is characterized as very realistic replica both the appearance and mechanism as the real ones. His contribution to the Japanese modelgun history is always remembered.
== Regulations ==
The initial modelguns which were made with full metal were originally classified as "toys" and fairly unregulated. When some models were made very close to real firearms both appearance and functionally and several misused cases happened, the authority increasingly intervened the modelgun industry to prevent them to be abused for criminal purposes. So the law was changed in different stages to make the products very safe, easily identifiable as toy guns and extremely hard to modify to fire any projectile.
In 1965, the Japanese government began regulating the replica firearms industry. Changes included was a requirement that the barrel have an internal insert to prevent tampering to fire any projectile.
In 1969, in accordance with the administrative guidance of the Police, the modelguns had to add a crown mark stamp on the body to distinguish it from real gun. However, these models only exist in very small quantity and are hardly found today.
The Firearms and Swords law revision in 1971 introduced more safety changes. It required that the barrel of all metal model handguns released thereafter must be completely blocked up in metal and must be entirely painted in white or yellow (excluding the grip). Since then, all metal model handguns produced were either painted in gold color or gold plated which was accepted as yellow color. Even the pre-1971 produced metal model handgun barrels needed to be blocked up and re-painted in yellow / gold color in order to comply with the law. However, the metal modelguns for export (mainly to RMI) could still be made in black color. Moreover, plastic modelguns started to get into the market as it is not governed by the law and can be produced in black color for more realistic look.
In 1975, the Japan Model Gun Manufacturing Cooperative Association (which later merged into Japanese Toy Gun Association (ASGK) (日本遊戯銃協同組合) in 1986) was formed by most modelguns makers. All members of the Association agreed to stamp on a "SM" mark (Safe Model) on the metal modelgun frame for safety conformation and identification purposes.
The second law revision in 1977 was even stricter. It prohibited the use of hard metal and required modelguns be produced with soft metal (hardness measured by Brinell scale (10/500) 91 HB or less) like zinc alloy in the main parts of metal modelguns. The metal model handguns must also have a completely sealed barrel and add a hardened steel rod molded inside a softer metal barrel to prevent attempts of modification and making it hollow. The front of cylinder chamber of revolvers must be blocked and the barrel and frame of metal model handguns must not be separable to prevent the interchange of the barrel. This new regulation prohibits further production of many full metal model handguns with separable barrel and slide. The ASGK manage the safety approval and the SMG (Safe Model Gun) mark replaced the SM mark on the metal models to identify the models meeting the new regulation.
However, the new law did not apply to modelgun made in plastics and so it also stimulated the production of more plastic modelguns by various manufacturers. The modelgun makers imposed some voluntary industrial restraints (self-regulation) to the plastic modelguns to prevent modification and for easy identification as modelgun. It requires the insert of a piece of hardened steel plate (called spacer) inside and across the barrel and this insert must be visible from the muzzle. Also, the front of cylinder chamber of revolvers must be blocked (fully or partially) by metal barrier too. After that, the ASGK manage the safety approval and a SPG (Safe Plastic Gun) mark started to appear on the plastic modelguns to indicate the conformance to the regulation. But Marushin withdrew from ASGK in 2007 and coordinated to launch the All Japan Toy Gun Safety Association (STGA)(全日本トイガン安全協会). Since then, the STGA mark appears on Marushin and Tanio Koba products for similar safety indication. KSC, Hudson and Kokusai also left ASGK and joined the Japan Air Sports Gun Association (JASG)(日本エアースポーツガン協会) in 2000s and JASG safety mark may appear on some of their newer products. However, some modelguns may not show any of the safety mark on the frame, but just have safety label affixed on the packing.
== Types ==
Modelguns can be found in many configurations and types. These range from small pistols/revolvers to rifles, shotguns, assault rifles and sub-machinegun, machineguns models. Among these, handgun models were and are still the most popular in Japan.
The earliest modelguns had a much simpler construction and a crude appearance. The so-called "automatic" handgun models only made use of gunpowder for ignition. The shell ejection and loading of cartridge action requires manually pulling the slide. In 1962, MGC improved the operation with the invention of Tanio Action or Slide Action mechanism which enable cycling the slide backward and forward to eject and load the cartridge with a pull of trigger. The system was also adopted by other modelgun makers in various models in many years. Of course, the construction and operation of these early stage modelguns were not comparable to the real guns. In 1968, MGC developed the breakthrough cap blowback technology which imitate the automated operation more closely to their real-life automatic counterparts.
The commonly available modelguns today are generally classified into display-only (or dummy / non-ignition) and cap-firing (or ignition) versions. There are far fewer "dummy" models than the "ignition" models in the market. Most dummy versions still highly replicate the appearance and internal mechanism of real counterparts with all moving parts work such that chamber / cycling dummy shells and field striping like real ones. The cap-firing modelguns besides highly replicate the appearance and internal mechanism as real guns like the dummy version, they are also able to "fire" the cartridge to produce spark, smoke, bang sound and slide cycling action (blowback) on automatic models.
There are 2 different cap firing systems for blowback modelguns.
The earlier models are with side fire system. The "firing block" (where supposed to have the firing pins for real guns) is in fact a stamped steel block which hits the cartridge rim area when hit by hammer. This system drives the entire cartridge case with cap into the detonator in the barrel to fire the internal cap. This system of course is very different from the design of the real guns.
In contrast, the later or newer models are Center fire system. They are very close replica to the real guns with the firing pin in the slide design. The firing pin hits the center of the cartridge "primer" which push the cap to the detonator to fire the cap.
The modelgun frame is made with materials either in all-metal or plastic. The metal version is mainly made with zinc alloy and many of them are made with slightly different sizes to the real ones to prevent interchange of critical parts. The early modelguns are mostly made with all-metal until 1977 when the law was changed to heavily regulate the metal model handguns. Since then, the plastic modelguns have become mainstream.
Plastic modelguns are usually either made with ABS (Acrylonitrile Butadiene Styrene) or Heavy Weight (HW) plastics. Though modelguns made with ABS plastics does not look and feel good, they are much cheaper and durable and have better cap blowback performance over metal versions. Most of the ABS plastic models are black in color but some are chrome or nickel plated to replicate the stainless-steel counterparts. The Heavy Weight (a MGC invention) plastic is the ABS resin mixed with some fine metal (usually zinc or iron) powder that makes it weigh heavier and look less plastic. In 1992, MGC released 'Super Real Heavy Weight' or SRH models which were a lot heavier than the normal HW plastic and so look and feel even more realistic. It contained such high amounts of metallic (iron) powder, that it magnets could be attracted to it. Since the SRH material is more brittle, the MGC SRH models were only made for some revolvers and a few dummy semi-auto handguns but the production only lasted for a short period of several months. However, the idea of SRH was adopted by other modelgun makers later. Kokusai released "Mega Heavy Weight" version, Marushin released "Giga Maxi Weight" version and Hobby Fix also released "Mega Weight" version for some of their products. Real McCoy's, Rampant Classic and Elan produce Rocken brand modelguns with Super Lock Light material (plastic mixed with tungsten powder) which has ultra high specific gravity as iron as well as better strength and finish texture. Elan further develop improved Super Lock Light R2.5 resin for its blowback and dummy Rocken models.
== Cartridges ==
The modelguns cannot use any live or blank cartridges. Instead, the modelguns use special designed cartridges dedicated to each model. The design of cartridges changed along with the evolution of modelguns and cap technology. Modelgun cartridges were developed and evolved over time for improved performance and realism. The "firing" of the cap inside the cartridge of commonly available modelguns today produces the visual effect of sparks/smoke, audible effect of bang sound and blowback action for automatic models. After firing, these cartridges can be reusable if cleaned and refilled the cap. Modelgun cartridges are in general not compatible among different manufacturers or different models. Different manufacturers have their own cartridge design and nomenclature as well as the parts count/description.
The very early stage modelgun cartridge was just for ignition purpose with the cap sitting at the tip of the one-piece metal cartridge. It could not perform blowback operation on automatic models. These precious models are mostly collector's pieces and are unlikely to be fired today.
In 1968, MGC developed a MG-Blowback cartridge for open detonator type blow back operation for their blowback models. The cartridge is extremely simple in construction and does not look like a real cartridge at all. It is typically just a single-piece brass open "tube" closed at one end with a machined extractor groove, thus also known as open cartridge. The cap is plugged deep into bottom of the cartridge and fired by a thick detonator pin. The exploded pressure between detonator pin and bottom of cartridge produces the blowback effect. However, it is difficult to achieve stable blowback performance as it uses paper caps which left residue built up on the detonator pin and inside the cartridge. The cartridge is also very hard to clean after fired.
In 1979, plastic cap with a phosphorus composition filler specially designed for modelgun was invented.
In 1980, Marushin developed its own closed type blowback design and it is called Plug Fire Cartridge (PFC). The cartridge has size and shape similar to real cartridges but can be screwed apart. It is made with machined brass multi-piece consisting of a simulated primer, base, piston and the "bullet". The plastic cap is plugged inside and sits on a piston which helps to keep the pressure of exploded gas to provide the blowback force. The blowback performance is much improved and cleanup is also easier.
Following the Marushin PFC, MGC also developed CP-Blowback cartridge (CP is an MGC acronym for Cap Piston that relates to the "piston" design of the MGC cartridges) to change from open cartridge to closed type cartridge in 1982. Since then, all other modelgun makers adopted similar closed type cartridge design for their blowback models – Piston Push Cartridge from Tokyo CMC, Blowback CTG Cartridge from Kokusai, Piston Fire Cartridge from Hudson. Later various modelgun makers further enhanced the design with additional rubber O-ring to further enhance the air-seal inside the cartridge. It provides even better blowback performance especially for the Heavy Weight models. This finally comes to the current blowback cartridges: - CP-HW cartridge from MGC, New Piston Fire cartridge from Hudson, New Plug Fire Cartridge from Marushin, Evolution cartridge from Tanaka, etc.
Surprisingly, Tanio Koba released the GM7 with plastic open blowback cartridge in 2009 and supplemented with aluminum alloy open cartridge later. However, it changed to an Easy CP blowback system in 2015.
For revolvers, there are 2 main design of cartridges.
MGC, CMC, Marui and Kokusai (early models) adopted closed cylinder design which had integral firing pins mounted at the front chamber end. The cap was plugged at the front tip of the cartridge (usually one-piece) and the cartridges were shorter than real ones.
KSC, Marushin, Tanaka, HWS, CAW and newer plastic Kokusai revolvers adopt open cylinder design which just have a steel plate to partially block the chamber end. The firing pin is integrated in the cartridge design and the cap is plugged inside the cartridge. The cartridge can be made in full length (or very close to) as the real one.
The recent models of Tanaka, Kokusai, Elan and HWS even make their cartridge's "bullet" portion screw separable and in silver or copper color so that they look very realistic lead / copper bullet cartridge. There are also some aftermarket cap-firing cartridges produced by Mulberry Field, B.W.C., C-Tec / Malugo and Tanio Koba for some selected compatible models of modelgun. Many of them are even designed to accommodate double or triple caps in their cartridge for enhanced blowback, sound and muzzle flash effect.
Mulberry Field, C-Tec / Malugo, Right, Elan and KSC make very nice full size dummy cartridges for display and manual operation purposes. The dummy cartridge has built in spring supported movable primer which is good for dry firing. It also comes with realistic screw-on copper or lead "bullet" head and genuine rim markings.
== Caps ==
The very early days of modelguns used the same paper roll caps imported from the United States for the cap guns. Later it was replaced by the Japanese made paper caps which were "printed" on flat sheets of red paper with perforations. However, paper caps had a safety problem because friction may ignite the caps and cause burns. Paper caps also had problems such as clogging of the burning residue of the baseboard and high corrosive of the gunpowder itself. Blowback performance by paper caps is unstable and malfunction frequently occurs in most models.
In 1979, a Japanese gunpowder manufacturer Kaneko developed a plastic bodied cap exclusively for modelguns in collaboration with MGC (MGC named it M.G. Cap). With the gunpowder contained in a small plastic cup, the cap is safer to handle and easier to load. The gunpowder used is less corrosive and less residue after burning. The plastic bodied cap also enhances the blowback performance as the cap acts as a seal inside the cartridge to maintain the exploded pressure. The caps are standardized to be either 7 mm or 5 mm in diameter for normal size and compact size cartridge. These Kaneko-produced modelgun caps eventually became universal and adopted by all modelgun manufacturers. Marushin named it "Plug Fire Cap". The most common type is marked as "Automatic" which uses gunpowder with a lower burning speed to enhance the blowback operation for automatic models. Kaneko also released a variant called Kanecap or Real Flame Cap which contains a metallic content that sparks brightly as well as smoke when the cap ignites to enhance the firing effect.
== Manufacturers ==
=== Defunct ===
The MGC and Hudson Industry are the 2 most famous long-established modelgun makers which first produced the original Japanese designed modelguns in 1962–63 and subsequently produced many different models in next few decades. Unfortunately, both of them are gone.
MGC closed the manufacturing and ceased all toy gun production in late 1994. The molds and production equipment were taken over by its parent company Taito and Shin Nippon Mokei (New Japan Model). The modelgun production was continued and traded as New MGC. But the company started selling its molds and production equipment from 2007 and production finally ceased in April 2010.
In December 2009, Hudson Industry suddenly closed its toy gun business and ceased all modelgun production.
Other early key makers are Tokyo CMC, Nakata and Kokusai (International Industry) which started modelgun production in mid-60s. Nakata and Tokyo CMC ceased modelgun business respectively in late 70s and 1985. In 2003 Kokusai went into bankruptcy after an earlier factory fire and was taken over by Sun Project. The modelgun production was resumed in Kokusai brand with the remaining modelgun molds. Later the molds and equipment were sold to Uriu Limited (a die casting Co.) which continued the production still in Kokusai brand until January 2018 when its modelgun production finally ceased.
There were some other smaller makers around 70s-80s like Malugo, KKS (Komoda Shoten), Suzuki, Asahi Toys (under the "Asahi Eagle" brand) and Matsushiro but they only produced just very few models.
Upon the closing down of the aforesaid manufacturers, it is fortunate that some or all their molds and manufacturing equipment were sold to other modelgun manufacturers to continue the model production.
Western Arms once produced a few modelgun models in 70s-80s. Tokyo Marui also produced some plastic modelgun kits in 80s-90s. Both Western Arms and Tokyo Marui produce airsoft only at present.
L&S Co. in Japan produced many 1:1 scale plastic modelgun kits (dummy models requiring glue to assemble) in 70s-80s which were widely exported worldwide. A few of their molds were later acquired by Academy in Korea before L&S was closed down in 1992. However, Academy only produced limited quantity of the modelgun kits in short period of time.
Rokuken is famous in its "ROCKEN" brand brass luxury modelgun though only produced in very small quantity. The production started from 1967 and it further partnered with Western Arms in 1974 to sell these high-priced brass modelguns. But the production was stopped in 1977 after the amendment of the Firearms and Sword law. However, Rocken brand and designed high grade plastic models are released from Real McCoy's, Rampant Classic and Elan from mid-90s.
=== Active ===
As of 2021, the active modelgun manufacturers in Japan are Marushin, Tanaka Works, HWS (Hartford Work Shop), KSC, CAW (Craft Apple Works), Tanio Koba, Elan and Hobby Fix. Among them, Marushin and HWS also offer modelgun kits for sale.
There are two other companies producing modelguns outside Japan: HawSan and Denix.
HawSan (or Hwasan / Wa Shan), a Taiwanese company, is the only company which produces many modern cap-firing capable modelguns outside Japan. HawSan is known for producing cap-firing full-metal handguns in black or silver color. It also produces single-use disposable cartridges with pre-installed caps. Since their modelgun products do not conform with the related Japanese laws, they are not allowed in Japan. However, the Company focus more on airsoft since 2020 when the Toy Gun law in Taiwan is revised to heavily regulate the modelguns.
Denix S.A., based in Spain, produces many replicas of historical weapons including flintlock and caplock dummy pistols for use as decorations or props. Its replica products cover very wide varieties from many centuries up to the 1980s. Though many of their modern replicas are made with full metal, only very few of them are capable to fire caps.
== See also ==
Cap gun
== References ==
== External links ==
Japanese Toy Gun Association (ASGK) (日本遊戯銃協同組合) Homepage
All Japan Toy Gun Safety Association (STGA)(全日本トイガン安全協会) Homepage
Japan Air Sports Gun Association (JASG)(日本エアースポーツガン協会) Homepage
Collector’s Armoury, Ltd.
Marushin Industry Co. Ltd.
Tanaka Works Co. Ltd.
HWS (Hartford Work Shop) Co. Ltd.
KSC Corp.
CAW (Craft Apple Works)
Tanio Koba Co. Ltd.
Elan Corp.
Hawsan Toys
Denix S.A. | Wikipedia/Model_gun |
Automotive design is the process of developing the appearance (and to some extent the ergonomics) of motor vehicles, including automobiles, motorcycles, trucks, buses, coaches, and vans.
The functional design and development of a modern motor vehicle is typically done by a large team from many different disciplines also included within automotive engineering, however, design roles are not associated with requirements for professional- or chartered-engineer qualifications. Automotive design in this context focuses primarily on developing the visual appearance or aesthetics of vehicles, while also becoming involved in the creation of product concepts. Automotive design as a professional vocation is practiced by designers who may have an art background and a degree in industrial design or in transportation design. For the terminology used in the field, see the glossary of automotive design.
== Design elements ==
The task of the design team is usually split into three main aspects: exterior design, interior design, and color and trim design. Graphic design is also an aspect of automotive design; this is generally shared amongst the design team as the lead designer sees fit. The design focuses not only on the isolated outer shape of automobile parts, but concentrates on the combination of form and function, starting from the vehicle package.
The aesthetic value will need to correspond to ergonomic functionality and utility features as well. In particular, vehicular electronic components and parts will give more challenges to automotive designers who are required to update on the latest information and knowledge associated with emerging vehicular gadgetry, particularly dashtop mobile devices, like GPS navigation, satellite radio, HD radio, mobile TV, MP3 players, video playback, and smartphone interfaces. Though not all the new vehicular gadgets are to be designated as factory standard items, some of them may be integral to determining the future course of any specific vehicular models.
=== Exterior design ===
The design team(s) responsible for the exterior of the vehicle develops the proportions, shape, and surface details of the vehicle. Exterior design is first done by a series of manual sketches and digital drawings. Progressively, more detailed drawings are executed and approved by appropriate layers of management, followed by digital rendering to images. Consumer feedback is generally sought at this point to help iteratively refine vehicle concepts according to the targeted market and will continue throughout the rest of the design refinement process. After more progressive refinement, industrial plasticine and or digital models are developed from and along with the drawings and images. The data from these models are then used to create quarter-scale and finally full-sized mock-ups of the final design. With three- and five-axis CNC milling machines, the clay model is first designed in a computer program and then "carved" using the machine and large amounts of clay. Even in times of photorealistic (three-dimensional) software and virtual models on power walls, the clay model is still the most important tool for a final evaluation of the exterior design of a vehicle and, therefore, is used throughout the industry.
=== Interior design ===
The designer responsible for the vehicles' interior develops the proportions, shape, placement, and surfaces for the instrument panel, seats, door trim panels, headliner, pillar trims, etc. Here the emphasis is on ergonomics and the comfort of the passengers. The procedure here is the same as with exterior design (sketch, digital model, and clay model).
=== Color and trim design ===
The color and trim (or color and materials) designer is responsible for the research, design, and development of all interior and exterior colors and materials used on a vehicle. These include paints, plastics, fabric designs, leather, grains, carpet, headliner, wood trim, and so on. Color, contrast, texture, and pattern must be carefully combined to give the vehicle a unique interior environment experience. Designers work closely with exterior and interior designers.
Designers draw inspiration from other design disciplines such as industrial design, fashion, home furnishing, architecture, and sometimes product design. Specific research is done into global trends to design for projects two to three model years in the future. Trend boards are created from this research to keep track of design influences as they relate to the automotive industry. The designer then uses this information to develop themes and concepts that are then further refined and tested on the vehicle models.
=== Graphic design ===
The design team also develops graphics for items, such as badges, decals, dials, switches, kick or tread strips, or liveries.
=== Computer-Aided Design and Class-A development ===
The sketches and rendering are transformed into 3D digital surface modeling and rendering for real-time evaluation with Math data in the initial stages. During the development process succeeding phases will require the 3D model fully developed to meet the aesthetic requirements of a designer as well as all engineering and manufacturing requirements. The fully developed CAS digital model will be re-developed for manufacturing meeting the Class-A surface standards that involve both technical as well as aesthetics. A Product Engineering team will further develop this data. These modelers usually have a background in industrial design or sometimes tooling engineering in the case of some Class-A modelers. Autodesk Alias and ICEM Surf are the two most widely used software tools for Class-A development. Uniform surface continuity is critical to ensure Class-A surface standards. The continuity of the areas is between the quality grades G0 through G3, with G3 guaranteeing the cleanest patch-to-patch transitions.
== Development process ==
=== Design development cycle ===
Several manufacturers have slightly varied development cycles for designing an automobile, but in practice, these are the following:
Design and consumer research
Concept development sketching
CAS (Computer Aided Styling)
Clay modeling
Interior buck model
Vehicle ergonomics
Class-A Surface Development
Color and trim
Vehicle graphics
The design process occurs concurrently with other product engineers who will be engineering the styling data for meeting performance, manufacturing, and safety regulations. From mid-phase, back-and-forth interactions between the designers and product engineers culminate into a finished product being manufacturing-ready.
Apart from this the engineering team parallelly works in the following areas. Product Engineering (Body In White Sheetmetal Design and Plastic engineering), NVH Development team, Prototype development, Powertrain engineering, Physical Vehicle validation, Tool and Die development, and Manufacturing process design.
=== Development team ===
The design team for a specific model consists of a chief designer and an exterior as well as an interior designer. In some cases, all three roles are done by one designer. Several junior designers are involved in the development process as well and make specific contributions all overseen by the chief designer. Apart from this, the color and trim designer works closely with other designers. The clay model team and digital model team work closely with the styling team all located within the studio. Apart from this, there would be studio heads, studio managers, and prototype engineers who would work across all teams in the studio. The total team size for developing a full car usually ranges from 25 to 40 members and the development time lasts for more than 24 months until signed-off for tooling and production. After that, a smaller team would be working until the vehicle launch.
== History ==
=== United States ===
In the United States, automotive design reached a turning point in the 1920s when the American national automobile market began reaching saturation. To maintain unit sales, General Motors head Alfred P. Sloan Jr. suggested annual model-year design changes to convince car owners that they needed to buy a new replacement each year, an idea borrowed from the bicycle industry (though Sloan usually gets the credit or blame). Critics called his strategy planned obsolescence. Sloan preferred the term "dynamic obsolescence". This strategy had far-reaching effects on the auto business, the field of product design, and eventually the American economy.
The smaller automakers could not maintain the pace and expense of yearly re-styling. Henry Ford did not like the model-year change because he clung to an engineer's notions of simplicity, the economics of scale, and design integrity. GM surpassed Ford's sales in 1931 and became the dominant company in the industry thereafter. The frequent design changes also made it necessary to use a body-on-frame rather than the lighter but less adaptable monocoque design used by most European automakers.
In the 1930s, Chrysler's innovations with aerodynamics helped launch the Chrysler Airflow in 1934, which was revolutionary and radical compared to contemporary vehicles. However, inadequate consumer acceptance of the advanced appearance of the cars forced a re-design of succeeding models of the Airflow. This marketing experience made the entire industry take note of the high risks involved in incorporating major design advancements into their production cars.
A major influence on American auto styling and marketing was Harley Earl, who is credited with inventing the idea of a concept car, and who brought the tailfin and other aeronautical design references to auto design starting with the rear fenders of the 1948 Cadillac. Another notable designer was Chrysler group's designer Virgil Exner, who developed the Forward look design in the mid-1950s. Exner is also credited with using wind tunnel testing to justify incorporating tailfins, thus moving the company away from boxy-looking cars into more aerodynamic and futuristic designs that were influenced by rockets after WWII. Other influential automotive designers include Raymond Loewy, who was responsible for a number of Studebaker vehicles such as the Avanti, and Gordon Buehrig, who was responsible for the Auburn 851, as well as the Cord 810 and 812.
Starting in the 1960s, Dick Teague, who spent most of his career with American Motors Corporation (AMC), originated the concept of using interchangeable body panels so as to create a wide array of different vehicles using the same stampings, starting with the AMC Cavalier. Teague was responsible for automotive designs such as the two-seat AMC AMX muscle car, the subcompact Gremlin, the Pacer, and Matador coupe, as well as the original and market segment-creating, Jeep Cherokee.
Additionally during the 1960s, Ford's first-generation Ford Mustang and Thunderbird marked another era leading into new market segments from Detroit. The Ford Mustang achieved record sales in its first year of production and established the pony car segment.
Personal injury litigation has affected the design and appearance of the car in the 20th century.
=== Europe ===
Until World War I, most automakers were concerned with mechanical reliability rather than the external appearance of their cars. Later, luxury and aesthetics became a demand, and also an effective marketing tool. Designs from each nation with their own strong cultural identity are reflected in their exterior and interior designs. World War II slowed the progress, but after the early 1950s, Italian designers set the trend and remained the driving force until the early part of the 1980s.
==== France ====
In France notable designs came from Bugatti and Avions Voisin. Of the mass-selling cars, Citroën launched their vehicles with innovative designs and engineering, aided by the styling of Flaminio Bertoni as evident from the Citroën DS. After World War II, with the decline of the coachbuilding industry, French automakers (except Citroën) followed British and other popular trends until they gained financial stability. During the 1980s, manufacturers like Renault cultivated their own strong design identities with designers like Patrick Le Quément. Peugeot, which was dependent on Pininfarina since the early post-war period, later established its own brand identity from the 1980s onwards. Its other company, Citroën, still retains its distinctive French innovations for its designs.
==== Great Britain ====
Great Britain was Europe's leading manufacturer of automobiles until the late-1960s. During that era, there were more British-based automakers than in the rest of Europe combined. The British automobile industry catered to all segments ranging from compact, budget, sports, utility, and luxury-type cars. Car design in Britain was markedly different from other European designs largely because British designers were not influenced by other European art or design movements, as well as the British clay modelers, used a different sweep set.
British cars until World War II were sold in most of the British colonies. Innovations in vehicle packaging and chassis engineering combined with global familiarity with British designs meant vehicles were acceptable to public tastes at that time. British skilled resources such as panel beaters, die machinists, and clay modelers were also available partly due to their involvement with the motorsport industry.
Still, during the 1960s, British manufacturers sought professional help from Italian designers and studios such as Giovanni Michelotti, Ercole Spada, and Pininfarina. Notable British contributions to automobile designs were the Morris Mini by Alec Issigonis, several Jaguar Cars by Sir William Lyons and Malcolm Sayer, Aston Martin DB Series, and several cars from Triumph and MG. Ford Europe, based in Great Britain, is notable for the Ford Sierra line, a work of Uwe Bahnsen, Robert Lutz, and Patrick le Quément. Other notable British designers include William Towns for Aston Martin, and David Bache for Land Rover and Range Rover, and Ian Callum for Jaguar.
In the late 1980s, Royden Axe (previously Chrysler UK Design Director) and Gordon Sked along with Gerry McGovern produced most notably the MGF and Rover 800
During the complex changes in the British car industry in the 1990s and beyond, a mix of designers worked on all of the remaining mainstream brands under one design director and in one studio. The director most involved was Geoff Upex, with his team of Richard Woolley, Dave Saddington, George Thomson, Alan Mobberley, and Martin Peach (colour and trim). Together they created the Rover 75, 45, and 25 (previously 400 and 200) the L322 Range Rover, the T5 platform-based Discovery and Range Rover sport, the Freelander 2, and the Mini as requested by BMW before the company was sold
==== Germany ====
Germany is often considered the birthplace of industrial design with the Bauhaus School of Design, before it was closed down by the Nazi regime. Ferdinand Porsche and his family played a significant role in German design. Mercedes-Benz passenger cars were also in the luxury segment and played an important role in German car design. After the 1980s, German design evolved into a distinctive Teutonic style often to complement their highly engineered cars suited to Autobahns. The early German design clues of the present-day owe some part to Italian designers like Giovanni Michelotti, Ercole Spada, Bruno Sacco, and Giorgetto Giugiaro. During the mid- and late-20th century one of the most influential coach builders/designers in Germany was Karmann.
German designs started gaining popularity after the 1980s, notable after the formation of Audi. Volkswagen, which was dependent on Marcello Gandini, Giorgetto Giugiaro, and Karmann, later formed the contemporary design language along with Audi. BMW entered the automobile design with sporty-looking everyday sedans using Giovanni Michelotti. These models were later enhanced by Ercole Spada into the 1980s, and Klaus Luthe until the mid-1990s. The American-born designer Chris Bangle was hired by BMW in the late-1990s to redefine the brand. Bangle incorporated new single-press technology for compound curves to add controversial styling elements to his designs.
The Porsche family contribution was instrumental in the evolution of Porsche cars, while the Italian designer Bruno Sacco helped create various Mercedes Models from the 1960s to the 1990s.
==== Italy ====
In Italy, Fiat and Alfa Romeo played a major role in car design. Many coachbuilders were dependent on these two major manufacturers. Italian manufacturers had a large presence in motorsports leading to several sport car manufacturers like Ferrari, Lancia, Lamborghini, Maserati, etc. During the late-1950s, Italian automobile designs gained global popularity coinciding with the modern fashion and architecture at that time around the world. Various design and technical schools in Turin turned out designers on a large scale. By the late-1960s, almost all Italian coachbuilders transformed into design studios catering to automakers around the world. The trend continued in the 1990s when the Japanese and Korean manufacturers sourced designs from these styling studios. One example is Pininfarina.
Some Italian designers whose design services were sought globally include Aldo Brovarone, Giovanni Michelotti, Ercole Spada, Bruno Sacco, Marcello Gandini, Giorgetto Giugiaro, and Walter de Silva.
==== Scandinavia ====
Sweden had Volvo and Saab as domestic automakers, and the nation's northern location required that cars needed to withstand Nordic climate conditions. The Scandinavian design elements are known for their minimalism and simplicity. One of the early original Scandinavian designs was the Saab 92001 by Sixten Sason and Gunnar Ljungström. Koenigsegg, founded in the 1990s, became Sweden's first domestic producer of high end sports cars, with many of their models featuring in house designs by Swedish designers.
==== Czechoslovakia ====
Before World War II and until the early-1990s, Czechoslovakia had a strong presence in the automotive industry with manufacturers like Skoda, Jawa, Tatra, CZ, Praga, and Zetor. Czech automobiles were generally known for their originality in mechanical simplicity and designs were remarkably Bohemian as evident from Tatra cars and Jawa motorcycles. During the Communist regime, the design started falling back and ultimately the domestic automakers ended up as subsidiaries of EU-based companies.
== See also ==
== References ==
== Further reading ==
Nikolaos Gkikas, ed. (2013). Automotive Ergonomics: Driver – Vehicle Interaction. Boca Raton, FL.: CRC Press. ISBN 9781439894255.
Lamm, Michael; Hollis, Dave (1996). A century of automotive style - 100 years of American car design. Stockton, CA: Lamm-Morada. ISBN 9780932128072.
== External links ==
Learning materials related to New car design at Wikiversity
Media related to Automotive design at Wikimedia Commons | Wikipedia/Car_design |
Butyric acid (; from Ancient Greek: βούτῡρον, meaning "butter"), also known under the systematic name butanoic acid, is a straight-chain alkyl carboxylic acid with the chemical formula CH3CH2CH2COOH. It is an oily, colorless liquid with an unpleasant odor. Isobutyric acid (2-methylpropanoic acid) is an isomer. Salts and esters of butyric acid are known as butyrates or butanoates. The acid does not occur widely in nature, but its esters are widespread. It is a common industrial chemical and an important component in the mammalian gut.
== History ==
Butyric acid was first observed in an impure form in 1814 by the French chemist Michel Eugène Chevreul. By 1818, he had purified it sufficiently to characterize it. However, Chevreul did not publish his early research on butyric acid; instead, he deposited his findings in manuscript form with the secretary of the Academy of Sciences in Paris, France. Henri Braconnot, another French chemist, was also researching the composition of butter and was publishing his findings and this led to disputes about priority. As early as 1815, Chevreul claimed that he had found the substance responsible for the smell of butter. By 1817, he published some of his findings regarding the properties of butyric acid and named it. However, it was not until 1823 that he presented the properties of butyric acid in detail. The name butyric acid comes from βούτῡρον, meaning "butter", the substance in which it was first found. The Latin name butyrum (or buturum) is similar.
== Occurrence ==
Triglycerides of butyric acid make up 3–4% of butter. When butter goes rancid, butyric acid is liberated from the glyceride by hydrolysis. It is one of the fatty acid subgroup called short-chain fatty acids. Butyric acid is a typical carboxylic acid that reacts with bases and affects many metals.
It is found in animal fat and plant oils, bovine milk, breast milk, butter, parmesan cheese, body odor, vomit and as a product of anaerobic fermentation (including in the colon). It has a taste somewhat like butter and an unpleasant odor. Mammals with good scent detection abilities, such as dogs, can detect it at 10 parts per billion, whereas humans can detect it only in concentrations above 10 parts per million. In food manufacturing, it is used as a flavoring agent.
In humans, butyric acid is one of two primary endogenous agonists of human hydroxycarboxylic acid receptor 2 (HCA2), a Gi/o-coupled G protein-coupled receptor.
Butyric acid is present as its octyl ester in parsnip (Pastinaca sativa) and in the seed of the ginkgo tree.
== Production ==
=== Industrial ===
In industry, butyric acid is produced by hydroformylation from propene and syngas, forming butyraldehyde, which is oxidised to the final product.
H2 + CO + CH3CH=CH2 → CH3CH2CH2CHOoxidation→butyric acid
It can be separated from aqueous solutions by saturation with salts such as calcium chloride. The calcium salt, Ca(C4H7O2)2 · H2O, is less soluble in hot water than in cold.
=== Microbial biosynthesis ===
Butyrate is produced by several fermentation processes performed by obligate anaerobic bacteria. This fermentation pathway was discovered by Louis Pasteur in 1861. Examples of butyrate-producing species of bacteria:
Clostridium butyricum
Clostridium kluyveri
Clostridium pasteurianum
Faecalibacterium prausnitzii
Fusobacterium nucleatum
Butyrivibrio fibrisolvens
Eubacterium limosum
The pathway starts with the glycolytic cleavage of glucose to two molecules of pyruvate, as happens in most organisms. Pyruvate is oxidized into acetyl coenzyme A catalyzed by pyruvate:ferredoxin oxidoreductase. Two molecules of carbon dioxide (CO2) and two molecules of hydrogen (H2) are formed as waste products. Subsequently, ATP is produced in the last step of the fermentation. Three molecules of ATP are produced for each glucose molecule, a relatively high yield. The balanced equation for this fermentation is
C6H12O6 → C4H8O2 + 2CO2 + 2H2
Other pathways to butyrate include succinate reduction and crotonate disproportionation.
Several species form acetone and n-butanol in an alternative pathway, which starts as butyrate fermentation. Some of these species are:
Clostridium acetobutylicum, the most prominent acetone and butanol producer, used also in industry
Clostridium beijerinckii
Clostridium tetanomorphum
Clostridium aurantibutyricum
These bacteria begin with butyrate fermentation, as described above, but, when the pH drops below 5, they switch into butanol and acetone production to prevent further lowering of the pH. Two molecules of butanol are formed for each molecule of acetone.
The change in the pathway occurs after acetoacetyl CoA formation. This intermediate then takes two possible pathways:
acetoacetyl CoA → acetoacetate → acetone
acetoacetyl CoA → butyryl CoA → butyraldehyde → butanol
For commercial purposes Clostridium species are used preferably for butyric acid or butanol production.
The most common species used for probiotics is the Clostridium butyricum.
=== Fermentable fiber sources ===
Highly-fermentable fiber residues, such as those from resistant starch, oat bran, pectin, and guar are transformed by colonic bacteria into short-chain fatty acids (SCFA) including butyrate, producing more SCFA than less fermentable fibers such as celluloses. One study found that resistant starch consistently produces more butyrate than other types of dietary fiber. The production of SCFA from fibers in ruminant animals such as cattle is responsible for the butyrate content of milk and butter.
Fructans are another source of prebiotic soluble dietary fibers which can be digested to produce butyrate. They are often found in the soluble fibers of foods which are high in sulfur, such as the allium and cruciferous vegetables. Sources of fructans include wheat (although some wheat strains such as spelt contain lower amounts), rye, barley, onion, garlic, Jerusalem and globe artichoke, asparagus, beetroot, chicory, dandelion leaves, leek, radicchio, the white part of spring onion, broccoli, brussels sprouts, cabbage, fennel, and prebiotics, such as fructooligosaccharides (FOS), oligofructose, and inulin.
== Reactions ==
Butyric acid reacts as a typical carboxylic acid: it can form amide, ester, anhydride, and chloride derivatives. The latter, butyryl chloride, is commonly used as the intermediate to obtain the others.
== Uses ==
Butyric acid is used in the preparation of various butyrate esters. It is used to produce cellulose acetate butyrate (CAB), which is used in a wide variety of tools, paints, and coatings, and is more resistant to degradation than cellulose acetate. CAB can degrade with exposure to heat and moisture, releasing butyric acid.
Low-molecular-weight esters of butyric acid, such as methyl butyrate, have mostly pleasant aromas or tastes. As a consequence, they are used as food and perfume additives. It is an approved food flavoring in the EU FLAVIS database (number 08.005).
Due to its powerful odor, it has also been used as a fishing bait additive. Many of the commercially available flavors used in carp (Cyprinus carpio) baits use butyric acid as their ester base. It is not clear whether fish are attracted by the butyric acid itself or the substances added to it. Butyric acid was one of the few organic acids shown to be palatable for both tench and bitterling. The substance has been used as a stink bomb by the Sea Shepherd Conservation Society to disrupt Japanese whaling crews.
The Dutch branch of Extinction Rebellion has used it as a chemical agent in a clothing store.
== Pharmacology ==
=== Pharmacodynamics ===
Butyric acid (pKa 4.82) is fully ionized at physiological pH, so its anion is the material that is mainly relevant in biological systems.
It is one of two primary endogenous agonists of human hydroxycarboxylic acid receptor 2 (HCA2, also known as GPR109A), a Gi/o-coupled G protein-coupled receptor (GPCR),
Like other short-chain fatty acids (SCFAs), butyrate is an agonist at the free fatty acid receptors FFAR2 and FFAR3, which function as nutrient sensors that facilitate the homeostatic control of energy balance; however, among the group of SCFAs, only butyrate is an agonist of HCA2. It is also an HDAC inhibitor (specifically, HDAC1, HDAC2, HDAC3, and HDAC8), a drug that inhibits the function of histone deacetylase enzymes, thereby favoring an acetylated state of histones in cells. Histone acetylation loosens the structure of chromatin by reducing the electrostatic attraction between histones and DNA. In general, it is thought that transcription factors will be unable to access regions where histones are tightly associated with DNA (i.e., non-acetylated, e.g., heterochromatin). Therefore, butyric acid is thought to enhance the transcriptional activity at promoters, which are typically silenced or downregulated due to histone deacetylase activity.
=== Pharmacokinetics ===
Butyrate that is produced in the colon through microbial fermentation of dietary fiber is primarily absorbed and metabolized by colonocytes and the liver for the generation of ATP during energy metabolism; however, some butyrate is absorbed in the distal colon, which is not connected to the portal vein, thereby allowing for the systemic distribution of butyrate to multiple organ systems through the circulatory system. Butyrate that has reached systemic circulation can readily cross the blood–brain barrier via monocarboxylate transporters (i.e., certain members of the SLC16A group of transporters). Other transporters that mediate the passage of butyrate across lipid membranes include SLC5A8 (SMCT1), SLC27A1 (FATP1), and SLC27A4 (FATP4).
=== Metabolism ===
Butyric acid is metabolized by various human XM-ligases (ACSM1, ACSM2B, ASCM3, ACSM4, ACSM5, and ACSM6), also known as butyrate–CoA ligase. The metabolite produced by this reaction is butyryl–CoA, and is produced as follows:
Adenosine triphosphate + butyric acid + coenzyme A → adenosine monophosphate + pyrophosphate + butyryl-CoA
As a short-chain fatty acid, butyrate is metabolized by mitochondria as an energy (i.e., adenosine triphosphate or ATP) source through fatty acid metabolism. In particular, it is an important energy source for cells lining the mammalian colon (colonocytes). Without butyrates, colon cells undergo autophagy (i.e., self-digestion) and die.
In humans, the butyrate precursor tributyrin, which is naturally present in butter, is metabolized by triacylglycerol lipase into dibutyrin and butyrate through the reaction:
Tributyrin + H2O → dibutyrin + butyric acid
== Biochemistry ==
Butyrate has numerous effects on energy homeostasis and related diseases (diabetes and obesity), inflammation, and immune function (e.g., it has pronounced antimicrobial and anticarcinogenic effects) in humans. These effects occur through its metabolism by mitochondria to generate ATP during fatty acid metabolism or through one or more of its histone-modifying enzyme targets (i.e., the class I histone deacetylases) and G-protein coupled receptor targets (i.e., FFAR2, FFAR3, and HCA2).
=== In the mammalian gut ===
Butyrate is essential to host immune homeostasis. Although the role and importance of butyrate in the gut is not fully understood, many researchers argue that a depletion of butyrate-producing bacteria in patients with several vasculitic conditions is essential to the pathogenesis of these disorders. A depletion of butyrate in the gut is typically caused by an absence or depletion of butyrate-producing-bacteria (BPB). This depletion in BPB leads to microbial dysbiosis. This is characterized by an overall low biodiversity and a depletion of key butyrate-producing members. Butyrate is an essential microbial metabolite with a vital role as a modulator of proper immune function in the host. It has been shown that children lacking in BPB are more susceptible to allergic disease and Type 1 Diabetes. Butyrate is also reduced in a diet low in dietary fiber, which can induce inflammation and have other adverse affects insofar as these short-chain fatty acids activate PPAR-γ.
Butyrate exerts a key role for the maintenance of immune homeostasis both locally (in the gut) and systemically (via circulating butyrate). It has been shown to promote the differentiation of regulatory T cells. In particular, circulating butyrate prompts the generation of extrathymic regulatory T cells. The low-levels of butyrate in human subjects could favor reduced regulatory T cell-mediated control, thus promoting a powerful immuno-pathological T-cell response. On the other hand, gut butyrate has been reported to inhibit local pro-inflammatory cytokines. The absence or depletion of these BPB in the gut could therefore be a possible aide in the overly-active inflammatory response. Butyrate in the gut also protects the integrity of the intestinal epithelial barrier. Decreased butyrate levels therefore lead to a damaged or dysfunctional intestinal epithelial barrier. Butyrate reduction has also been associated with Clostridioides difficile proliferation. Conversely, a high-fiber diet results in higher butyric acid concentration and inhibition of C. difficile growth.
In a 2013 research study conducted by Furusawa et al., microbe-derived butyrate was found to be essential in inducing the differentiation of colonic regulatory T cells in mice. This is of great importance and possibly relevant to the pathogenesis and vasculitis associated with many inflammatory diseases because regulatory T cells have a central role in the suppression of inflammatory and allergic responses. In several research studies, it has been demonstrated that butyrate induced the differentiation of regulatory T cells in vitro and in vivo. The anti-inflammatory capacity of butyrate has been extensively analyzed and supported by many studies. It has been found that microorganism-produced butyrate expedites the production of regulatory T cells, although the specific mechanism by which it does so is unclear. More recently, it has been shown that butyrate plays an essential and direct role in modulating gene expression of cytotoxic T-cells. Butyrate also has an anti-inflammatory effect on neutrophils, reducing their migration to wounds. This effect is mediated via the receptor HCA1.
In the gut microbiomes found in the class Mammalia, omnivores and herbivores have butyrate-producing bacterial communities dominated by the butyryl-CoA:acetate CoA-transferase pathway, whereas carnivores have butyrate-producing bacterial communities dominated by the butyrate kinase pathway.
The odor of butyric acid, which emanates from the sebaceous follicles of all mammals, works on ticks as a signal.
=== Immunomodulation and inflammation ===
Butyrate's effects on the immune system are mediated through the inhibition of class I histone deacetylases and activation of its G-protein coupled receptor targets: HCA2 (GPR109A), FFAR2 (GPR43), and FFAR3 (GPR41). Among the short-chain fatty acids, butyrate is the most potent promoter of intestinal regulatory T cells in vitro and the only one among the group that is an HCA2 ligand. It has been shown to be a critical mediator of the colonic inflammatory response. It possesses both preventive and therapeutic potential to counteract inflammation-mediated ulcerative colitis and colorectal cancer.
Butyrate has established antimicrobial properties in humans that are mediated through the antimicrobial peptide LL-37, which it induces via HDAC inhibition on histone H3. In vitro, butyrate increases gene expression of FOXP3 (the transcription regulator for Tregs) and promotes colonic regulatory T cells (Tregs) through the inhibition of class I histone deacetylases; through these actions, it increases the expression of interleukin 10, an anti-inflammatory cytokine. Butyrate also suppresses colonic inflammation by inhibiting the IFN-γ–STAT1 signaling pathways, which is mediated partially through histone deacetylase inhibition. While transient IFN-γ signaling is generally associated with normal host immune response, chronic IFN-γ signaling is often associated with chronic inflammation. It has been shown that butyrate inhibits activity of HDAC1 that is bound to the Fas gene promoter in T cells, resulting in hyperacetylation of the Fas promoter and up-regulation of Fas receptor on the T-cell surface.
Similar to other HCA2 agonists studied, butyrate also produces marked anti-inflammatory effects in a variety of tissues, including the brain, gastrointestinal tract, skin, and vascular tissue. Butyrate binding at FFAR3 induces neuropeptide Y release and promotes the functional homeostasis of colonic mucosa and the enteric immune system.
=== Cancer ===
Butyrate has been shown to be a critical mediator of the colonic inflammatory response. It is responsible for about 70% of energy from the colonocytes, being a critical SCFA in colon homeostasis. Butyrate possesses both preventive and therapeutic potential to counteract inflammation-mediated ulcerative colitis (UC) and colorectal cancer. It produces different effects in healthy and cancerous cells: this is known as the "butyrate paradox". In particular, butyrate inhibits colonic tumor cells and stimulates proliferation of healthy colonic epithelial cells. The explanation why butyrate is an energy source for normal colonocytes and induces apoptosis in colon cancer cells, is the Warburg effect in cancer cells, which leads to butyrate not being properly metabolized. This phenomenon leads to the accumulation of butyrate in the nucleus, acting as a histone deacetylase (HDAC) inhibitor. One mechanism underlying butyrate function in suppression of colonic inflammation is inhibition of the IFN-γ/STAT1 signalling pathways. It has been shown that butyrate inhibits activity of HDAC1 that is bound to the Fas gene promoter in T cells, resulting in hyperacetylation of the Fas promoter and upregulation of Fas receptor on the T cell surface. It is thus suggested that butyrate enhances apoptosis of T cells in the colonic tissue and thereby eliminates the source of inflammation (IFN-γ production). Butyrate inhibits angiogenesis by inactivating Sp1 transcription factor activity and downregulating vascular endothelial growth factor gene expression.
In summary, the production of volatile fatty acids such as butyrate from fermentable fibers may contribute to the role of dietary fiber in colon cancer. Short-chain fatty acids, which include butyric acid, are produced by beneficial colonic bacteria (probiotics) that feed on, or ferment prebiotics, which are plant products that contain dietary fiber. These short-chain fatty acids benefit the colonocytes by increasing energy production, and may protect against colon cancer by inhibiting cell proliferation.
Conversely, some researchers have sought to eliminate butyrate and consider it a potential cancer driver. Studies in mice indicate it drives transformation of MSH2-deficient colon epithelial cells.
=== Potential treatments from butyrate restoration ===
Owing to the importance of butyrate as an inflammatory regulator and immune system contributor, butyrate depletions could be a key factor influencing the pathogenesis of many vasculitic conditions. It is thus essential to maintain healthy levels of butyrate in the gut. Fecal microbiota transplants (to restore BPB and symbiosis in the gut) could be effective by replenishing butyrate levels. In this treatment, a healthy individual donates their stool to be transplanted into an individual with dysbiosis. A less-invasive treatment option is the administration of butyrate—as oral supplements or enemas—which has been shown to be very effective in terminating symptoms of inflammation with minimal-to-no side-effects. In a study where patients with ulcerative colitis were treated with butyrate enemas, inflammation decreased significantly, and bleeding ceased completely after butyrate provision.
=== Addiction ===
Butyric acid is an HDACTooltip histone deacetylase inhibitor that is selective for class I HDACs in humans. HDACs are histone-modifying enzymes that can cause histone deacetylation and repression of gene expression. HDACs are important regulators of synaptic formation, synaptic plasticity, and long-term memory formation. Class I HDACs are known to be involved in mediating the development of an addiction. Butyric acid and other HDAC inhibitors have been used in preclinical research to assess the transcriptional, neural, and behavioral effects of HDAC inhibition in animals addicted to drugs.
== Butyrate salts and esters ==
The butyrate or butanoate ion, C3H7COO−, is the conjugate base of butyric acid. It is the form found in biological systems at physiological pH. A butyric (or butanoic) compound is a carboxylate salt or ester of butyric acid.
=== Examples ===
==== Salts ====
Sodium butyrate
==== Esters ====
Butyl butyrate
Butyryl-CoA
Cellulose acetate butyrate (aircraft dope)
Estradiol benzoate butyrate
Ethyl butyrate
Methyl butyrate
Pentyl butyrate
Tributyrin
== See also ==
List of saturated fatty acids
Histone
Histone-modifying enzyme
Histone acetylase
Histone deacetylase
Hydroxybutyric acids
α-Hydroxybutyric acid
β-Hydroxybutyric acid
γ-Hydroxybutyric acid
Oxobutyric acids
2-Oxobutyric acid (α-ketobutyric acid)
3-Oxobutyric acid (acetoacetic acid)
4-Oxobutyric acid (succinic semialdehyde)
β-Methylbutyric acid
β-Hydroxy β-methylbutyric acid
== Notes ==
== References ==
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Butyric Acid". Encyclopædia Britannica (11th ed.). Cambridge University Press.
== External links ==
NIST Standard Reference Data for butanoic acid | Wikipedia/Butyrate |
In miniature wargaming, players enact simulated battles using scale models called miniature models, which can be anywhere from 2 to 54 mm in height, to represent warriors, vehicles, artillery, buildings, and terrain. These models are colloquially referred to as miniatures or minis.
Miniature models are commonly made of metal, plastic, or paper. They are used to augment the visual aspects of a game and track position, facing, and line of sight of characters. Miniatures are typically painted and can be artfully sculpted, making them collectible in their own right. Pre-painted plastic figures, such as Clix miniatures produced by WizKids and unpainted plastic figures for Warhammer by Games Workshop, have become popular. The hobby of painting, collecting, and playing with miniatures originated with toy soldiers, though the latter were generally sold pre-painted.
== Materials ==
Miniature models are derived from toy soldiers which were constructed of a variety of materials, These toy figures came to be mass produced from tin in late 1700s Germany, where they were called Zinnsoldaten (lit. "tin soldiers"). These early figures were flat models commonly called "flats", and became quite common in western Europe. By the mid 1800s manufactures in several countries were producing 3d miniatures of tin and lead alloys, common called white metal. In 1993, the New York legislature introduced a bill outlawing lead in miniatures, citing public health concerns. Many miniature manufacturers, anticipating that other states would also impose bans, began making figures with lead-free alloys, often at increased prices. After months of debate and protests by miniature manufacturers and enthusiasts, New York Governor Mario Cuomo signed a bill which exempted miniatures from the state's public health law. Despite this, most American manufacturers continued to use non-lead alloys.
In the 20th century miniatures would also be manufactured from plastic and composite materials.
Some wargames use "box miniatures", consisting of card stock folded into simple cuboids with representative art printed on the outside. Other games use 2d cardboard miniatures that are either held in a base or folded into a triangular tent.
== Scale heights ==
Historically the size of miniatures was described in absolute scale in various different systems of measurement, most commonly in metric and English units. A 28mm miniature means that the size of the miniature will be 28mm from the feet of the mini to the chosen reference point. The most common miniatures were the 54 mm European miniatures and the 2 1/4" English models which are commonly considered to be 1:32 scale. Early wargames such as H.G Wells Little Wars used these commonly available miniatures. With metrication in the United Kingdom, United States manufacturers began to use the metric system to describe miniatures, as opposed to the previously popular customary units, so that their table-top wargaming models would be compatible. Today, the scale of a figure is often described in millimeters, for example one of the most common scales is 28 mm.
Manufacturers set up a size of the miniature and try to make every miniature similar size or at least have an average with the size they've set up. While a model may be described as 28 mm the actual height of the model may be different. This is because of a number of factors such as manufacturer, model proportion, method of measuring the model, the model's pose, and what sort of man the model is meant to represent. A manufacturer might advertise its figures as 28 mm, but their products may be over 30 mm tall. In 28 mm scale, short characters such as dwarves, hobbits, and goblins might be represented by figures in the 15 to 20 mm range while taller characters like ogres, trolls and dragons would use 30 mm or larger figures. Manufacturer's use of scale is not uniform and can deviate by as much as 30%. Some manufacturers measure figure height from the feet to the eyes rather than the top of the head; therefore, a figure that is 30mm to the top of its head could be considered to be a 28mm miniature. Figures of 15 mm, 20 mm, 25 mm, 28 mm, 30 mm, 32 mm, and 35 mm are the most common for role-playing and table-top games. Smaller figures of 2 mm, 6 mm, 10 mm, 15 mm, and 20 mm are used for mass-combat wargames. Large sizes such as 40 mm and 54 mm were popular with wargamers in the past and are still used by painters and collectors. While the large miniatures have become popular again since the late 20th century, they are not as popular as the smaller sizes.
In many games there is a definite scale specified for the square grid that the game is played upon. One of the most common is 1 inch represents 5 feet. This specifies an exact scale of 1:60. That implies that a 28 mm tall figurine represents a 1.68 m (5 ft 6 in) person – which is a reasonable number for a modern 50th percentile male (See: Human height). Another popular scale is 1/72 or 1 inch equals 6 foot which uses 20 mm, to 25 mm miniatures. It is mostly used for historical gaming in part due to a wide selection of 1/72 scale models. Figures are commonly used with a variety of scales. It is not uncommon for there to be a mismatch between the game scale and miniature size. Chainmail used a scale of 1:360, appropriate to 5 mm miniatures, but was played with 30 mm miniatures, and the conceit that each figure represented 20 men. In the table below, figure height alone (excluding base thickness) is the feature from which approximate scale is calculated.
Scales smaller still are used when the game involves large vehicles (such as starships or battleships). For instance Axis & Allies Naval Miniatures: War at Sea uses 1:1800 scale, and scales down to 1:6000 are seen. There is no equivalent "mm" number for these scales as individual figures would be nearly microscopic and are not used as such in the games.
=== Heroic scale ===
A further complication is differing interpretations of body proportions. Many gaming figures are unrealistically bulky for their height, with oversized feet, heads, hands, wrists, and weapons. Making these parts oversized allows for more details to be present in the miniatures. Some of these exaggerations began as concessions to the limitations of primitive mold-making and sculpting techniques, but they have evolved into stylistic conventions. Figurines with these exaggerated features are often referred to as heroic scale.
=== Scale creep ===
There is a noted tendency in miniature figure manufacture where over time for bigger and bigger figures to be produced. Larger models were easier to produce correctly, especially in the 20th century; bigger details come out better, and larger surfaces are easier to paint. When a company sees that people are still buying the larger models, that's an incentive for them to continue making larger ones.
== Miniature figure scale ==
This is a relative scale that compares the size of the model to the size of a real life object. This ratio will show how many times the model is smaller than the original size. The meaning of 15 mm (for example) is therefore dependent on a defined reference height. Thus 15 mm in the context of a dwarven world where the reference humanoid is 60 inches (152 cm) tall, is not equivalent to 15 mm in the context an NBA model where the reference humanoid is 2 meters tall. Both models can be described as 15 mm, but the real world sizes depend on the size of the reference humanoid. In practice, the reference humanoid is generally assumed to be the idea of the average height of the human male, within a 6-inch (15 cm) interval between 5.5 and 6 feet (168 and 183 cm), unless otherwise indicated by the designer. Average human height is heavily dependent on the population measured within a geographical region and historical era.
The following chart provides a numerical relationship between model scale and multiple figurine scales based on the platonic idea of the height of a human being (humanoid).
== Painting ==
Many role-playing gamers and wargamers paint their miniatures to differentiate characters or units on a gaming surface (terrain, battle mat, or unadorned table top).
Fantasy, role-playing, miniatures, and wargaming conventions sometimes feature miniature painting competitions, such as Games Workshop's Golden Demon contest. There are also many painting competitions on the internet.
== Manufacture ==
There are two basic methods of manufacturing figures: centrifugal/gravity casting and plastic injection casting.
Most metal and resin figures are made through spin casting. Larger resin models, like buildings and vehicles, are sometimes gravity cast, which is a slower process. To gravity cast, a sculptor develops a master figure, which is then used to create rubber master and production moulds. The production moulds are used to cast the final commercial figures.
Polyethylene and polystyrene figures are made by injection moulding. A machine heats plastic and injects it under high pressure into a steel mould. This is an expensive process; it is only cost effective when manufacturing large amounts of figures, since the quantity renders the cost per cast minimal. Many miniatures companies do not produce their figures themselves but leave the manufacturing to specialized casting companies or miniatures companies that have casting facilities.
== Sculpting ==
Most miniatures are hand sculpted using two-component epoxy putties in the same size as the final figure. The components of the putty are mixed together to create a sculpting compound that hardens over 48 hours. Some common brands include Polymerics Kneadatite blue\yellow (also known as "green stuff" and "Duro" in Europe), Milliput, A&B, Magic sculpt, and Kraftmark's ProCreate.
Until recently, sculptors avoided polymer clays as they cannot withstand the traditional mould-making process. Modern techniques using RTV silicone and softer-quality rubbers have made it possible to use weaker materials, so that polymer clay masters have become more common. Fimo clay is popular, though due to the individual properties of certain colours, only a limited selection of colours is used.
Masters for plastic miniatures are often made in a larger scale, often three times the required size. The master is measured with a probe linked to a pantograph that reduces the measurements to the correct size and drives the cutter that makes the moulds.
A more recent development is the use of digital 3D models made by computer artists. These digital models create a physical model for mould-making using rapid prototyping techniques. Alternatively, they can be used directly to drive a computer numerical control machine that cuts the steel mould. They can also simply skip moulding steps and directly produce miniatures from 3D models.
== Miniatures in Dungeons & Dragons ==
Originally, Dungeons & Dragons was an evolution of the Chainmail medieval miniatures game, with the distinction that each player controlled a single figure and had a wider variety of actions available. The original D&D boxed set bore the subtitle, "Rules for Fantastic Miniature Wargames Campaigns Playable with Paper and Pencil and Miniature Figures". However, Dungeons & Dragons did not require miniatures, referring to them as "only aesthetically pleasing". Advanced Dungeons & Dragons likewise included a relatively short section describing miniature use, in conjunction with the official AD&D miniatures being produced at the time. As the game developed, miniatures became more of an optional add-on. The AD&D 2nd Edition accessory Player's Option: Combat & Tactics introduced a more elaborate grid-based combat system that emphasized the use of miniatures; a streamlined version of some of these concepts appeared in D&D 3rd edition. Although not strictly necessary, the 4th edition of the game assumes the use of miniatures, and many game mechanics refer explicitly to the combat grid. In addition to reducing ambiguity about the size and position of characters, this allows the game to specify rules for reach, threatened areas, and movement rates. The 5th edition de-emphasized these mechanics, and returned the use of miniatures to mostly optional.
== 2D miniatures ==
Some games feature miniatures printed on cardboard or cardstock, and some companies have published such miniatures to be used in place of miniature models.
Steve Jackson Games published the Cardboard Heroes line, and included cardstock miniatures in Steve Jackson's Man to Man, and then in the GURPS Basic Set and supplements such as GURPS Autoduel.
Zargonians was another early line of cardboard miniatures.
The Dungeons & Dragons Basic game included cardstock miniatures in supplements and adventures such as The Kidnapping of Princess Arelina, The Revenge of Rusak, The Veiled Society, and The Gem and the Staff.
Marvel Super Heroes by TSR included cardstock miniatures, and was supplemented by Adventure Fold-Up Figures and more in Pit of the Viper.
Other games that featured such 2D miniatures include Star Patrol, Ringworld, Dragonroar, Judge Dredd: The Role-Playing Game, TWERPS, and Space: 1889.
== See also ==
Meeple
Miniature conversion
Model figure
List of gaming miniatures companies
== References == | Wikipedia/Miniature_model_(gaming) |
Nürnberger Zinkdruckguß-Modelle GmbH (English: Nuremberg Diecast Models, mostly known for its initials NZG) is a German manufacturer of diecast scale models primarily in 1:50 scale for use both as toys and promotional models mainly by heavy transport and construction equipment manufacturers.
As seen in the name, the company is based in Nuremberg, Germany. Car models were also important as well as jet engine, aircraft, and stamping press models were also produced by NZG. A main company in competition with NZG, especially in production of construction vehicles in diecast for promotional purposes, is Conrad Models.
== History ==
According to the NZG website, Gerhard Schmid and Betty Hauer started NZG Modelle in 1968, when shop was set up in the second floor of a furniture company. The business soon moved to a 10,000 sq ft (930 m2) site at Sigmundstraße industrial estate. The first model produced was a Weserhutte wheeled crane, in that year. By 1974, at least 30 models were in the NZG range were noted in David Sinclair's Catalog. Sinclair, in the mid-1960s was one of the first importers to bring lesser known European brands to the U.S. Since then, over 700 different models have been produced and the company makes over 400,000 models a year.
In 1986 the company was operated by Inge Ludwig (née Schmid) and Hannelore Hauer. In 2000, NZG passed completely to the Ludwig family. Inge and Michael Ludwig run the company today.
Scales produced are 1:25, 1:50, and 1:87, as well as commercial vehicle models in 1:43. Special models require at least a 300 piece production order.
== Not toys and not for children ==
NZG specializes in a wide variety of heavy equipment types ranging from hand pallet movers, forklifts, scissors lifts, reach stackers, power generators and skidsteers to front loaders, shovels, excavators, graders, and mammoth ore carrying dump trucks. Caterpillar and other engines and machinery are sometimes also made and displayed free-standing. Some offerings, like pavement profilers, road finishers, asphalt strippers, road rollers, pipelayers, large cranes and drill rigs have also been offered, and NZG seems to have the market corner in promoting many models for a variety of manufacturers. Considering the variety of commercial model vehicles and equipment, one sees that details are intricate and sometimes delicate. To call NZG models 'toys' is too simple - they are precise replicas of the real thing - and quite sophisticated.
Marques represented are from a broad range, and include MAN, New Holland, Volvo, Caterpillar, FAUN, Grove, Terex and Liebherr, to name just a handful. Chinese built bulldozers are reproduced. Larger NZG trucks, like the Terex and Liebherr ore carriers are quite expensive, sometimes costing as much as 500 U.S. dollars, but most models seem to sell for anywhere between US $50 and US $150.
=== Precision automobile promos ===
Diecast model car collectors have become accustomed to NZG's replicas of Porsches and Mercedes-Benzes which were often used as dealer promotional models. NZG Mercedes diecast promos were commonly seen in dealers and recognizable by their simple, but ubiquitous silver boxes with the blue markings. Design and concept for models and packaging were similar to Conrad Models which focused more on the Audi make, and also Cursor Modell which also produced Mercedes-Benz as well as BMW promotionals.
Most cars were in 1:43 scale, but some were larger, like the No. 82 Mercedes 420/500/560 SEC coupes which were 1:35 scale (almost 5½ inches long). Other Mercedes offered were the 380 SEC / 500 SEC and 280 SEL sedans. On the base was stamped "Made in the Federal Republic of Germany". Stern stickers were commonly found on the bases warning that the models were "not toys and not for children."
Most NZG cars were produced in the 1980s and 1990s. A variety of vans were also produced (FIAT, Peugeot, and Citroen) in the 1990s. No cars seem to have been produced past 2002, as the company continued to focus more on its trucks and construction vehicles. Many car models were manufactured, and remain widely available at reasonable prices.
Cars rivaled companies like fellow German Schuco Modell or the French Solido in detail and realism. All doors, hood, and trunk usually opened. Body proportions were spot on. Clear plastic lenses were used for headlights (no toy-like faceted jewels here) and tail light lenses were separately cast in red plastic. NZG also was adept at chrome plating small emblems and grille details that other diecast manufacturers would not attempt on models three times the size. Wheel designs were unique to each vehicle, for example, incorporating Mercedes or Porsche logos. Unlike Solido and Schuco, however, as well-done as they were, trucks and construction equipment were NZGs bread-and-butter, not cars.
== Marketing ==
There are similarities in marketing and relationships with other model companies in the 1980s like Gescha/Conrad Models and Cursor Models, who produced similar promotional models for truck and automobile companies. The collector gets used to seeing the same style silver and black boxes whether the model was produced by NZG or Cursor. Also, some NZG Models are also marketed under the Conrad name. About the late 1980s, some dies were also sold to the Bulgarian company, Mikro'67 and produced in the city of Mir.
== Other lines ==
NZG now consists of several lines of other model subsidiaries including TWH and Sword which are American Companies licensing NZG products. More autonomous are Premium ClassiXXs, producing classic German cars, vans and motorcycles in a variety of scales; Bubmobile and JNF Toys which reproduce classic 1950s windup toys in the Schuco Modell tradition and also HO scale vehicles. Lastly, is the Y-Serie of modern military trucks and equipment.
== See also ==
Model construction vehicle
Engineering vehicle
Die-cast toy
Scale model
Mikro'67
== References ==
== External links ==
Official website
NZG made in Bulgaria, collector's site | Wikipedia/NZG_Models |
Control line (also called U-Control) is a simple and light way of controlling a flying model aircraft. The aircraft is typically connected to the operator by a pair of lines, attached to a handle, that work the elevator of the model. This allows the model to be controlled in the pitch axis. It is constrained to fly on the surface of a hemisphere by the control lines.
The control lines are usually either stranded stainless steel cable or solid metal wires of anywhere from 0.008 in (0.20 mm) to 0.021 in (0.53 mm). Sewing thread or braided fishing line may be used instead of wires, but air resistance is greater. A third line is sometimes used to control the engine throttle, and more lines may be added to control other functions. Electrical signals sent over the wires are sometimes used in scale models to control functions such as retracting undercarriage and flaps.
There is also a control system that uses a single solid wire, this is called Monoline. When the pilot twists the wire around its axis, a spiral inside the airplane spins to move the elevator. While it can be used with some success on any type of model, it is best for speed models where the reduced aerodynamic drag of the single line is a significant advantage. The control provided is not as precise as the two-line control system.
Almost all control-line models are powered with conventional model aircraft engines of various types. It is possible to fly control-line models that do not use on-board propulsion, in a mode called "whip-powered", where the pilot "leading" the model, whose lines are attached to a fishing or similar pole, supplying the necessary energy to keep the airplane aloft, in a fashion similar to kite-flying.
== History ==
Early versions merely constrained the model to fly in a circle but offered no control. This is known as round-the-pole flying. The origins of control-line flight are obscure, but the first person to use a recognizable system that manipulated the control surfaces on the model is generally considered to be Oba St. Clair, in June 1936, near Gresham, Oregon. St. Clair's system used a rather large apparatus similar to a television antenna, onto which many lines were attached. This system is very different from those currently in use on modern control line models. It is of interest to note that St. Clair only produced one model, the Miss Shirley, that used this system, which he called "the Full House." To date, there is no evidence to show anyone else ever built a plane to use the Full House system.
The name most associated with the inventions and promotion of control line, and the inventor of the formerly patented system known as "U-Control" (which was a trademark, and is the system in use on virtually every two-line control line model today) was Nevilles E. " Jim" Walker. His "American Junior" company was by far the biggest producer of models and held numerous patents on the two-line system until overturned during a patent infringement suit by Walker against Leroy M Cox, based on "prior art" from St. Clair in the 1955 trial. One of the most coveted prizes in control-line aerobatics competition sanctioned by the AMA, awarded to the winner of a flyoff between the US Junior, Senior, and Open age class Champions, was originally provided by and is named for Walker. This is one of the oldest perpetual trophies in modeling that is still awarded.
== The airframe ==
Control-line models are built of the same basic materials and construction methods as R/C and free flight models. Control-line model construction varies with the category of model. Aerobatics and combat models are relatively lightly built compare to R/C models as they need high maneuverability in the limited space offered by the control line hemisphere. They are typically built with traditional materials like balsa wood, plywood, paper, plastic, spruce, and polystyrene foam, but modern composite and graphite/epoxy are occasionally used in high-load applications. Combat models must also be relatively easy and quick to build, as mid-air collisions and crashes are common.
Aerobatic model construction is typically quite complex and may require many hundreds of hours. Speed models must be very sturdy to withstand the forces of line tension and to permit a very rigid engine mount for maximum engine performance. Speed models are generally built around an aluminum or magnesium "pan" that forms about half the fuselage. Little or no maneuverability required, as once at speed the model's altitude is maintained by centripetal Acceleration. Racing models need to be both relatively light for good acceleration from the start, or after a pit stop, and to reduce the pitch of the airfoil required to maintain lift. Race Aircraft also be fairly strong to withstand the pit man catching the model after landing.
To control the airplane, the lines must remain in tension. Centripetal Acceleration is generally sufficient to maintain line tension if the airplane is properly "trimmed" (adjusted), but sometimes additional features such as rudder offset and engine offset are added to provide extra tension. It is of interest to note, that when a control line model does a loop, it no longer flies on the edge of a hemisphere, but traverses the edge of a cone, a planar path, and the motion of the model produces no centripetal acceleration. In the condition of flying a loop, other factors must therefore provide the line tension, such as engine offset, or lead-out rake. Weight in the outboard wing tip is usually used to balance the weight of the lines. Top aerobatics models typically have a large number of adjustable features like tip weight boxes, adjustable rudder offset, adjustable line sweep, and adjustable elevator and flap controls. Some aerobatics models use a variable rudder system (commonly called the Rabe rudder after its inventor, Al Rabe) to vary the rudder offset during flight. The adjustment of the various adjustable features on a modern stunt model can become quite complex.
Many models also feature a longer inboard wing; aerobatics models use this to balance the lift from side-to-side, compensating for the difference in velocity from inboard to outboard wing, while some speed models use only an inboard wing, which eliminates the drag of the outboard wing completely (these models are colloquially referred to as "Sidewinders"). In general 2/3rds of the aerodynamic drag of the entire control line model systems (Plane, Lead-Outs, Lines/Connectors, Handle) is created by the lines/connectors.
In general there are two types of fuselage construction that are used in control line: "profile" (flat) and "built up". These are built with differing types of wings depending on the specific use of the aircraft. Profile models, where the fuselage is cut out from a single relatively thin sheet of wood with the "profile" of the airplane, are simple to build and repair, and are very common on trainer models. Sometimes the vibration of the engine causes poor engine runs on profile models. Built-up fuselages are much more difficult to build but generally look better and offer superior engine runs.
== Controls ==
The aircraft is typically controlled by a set of 20–70-foot lines usually of multi strand stainless steel, single strands of piano wire, or G.S.U.M.P. (Gel Spun Ultra-high-molecular-weight polyethylene, made by DuPont). For sport flying, non-metallic lines of kevlar, dacron, or other low-stretch fiber materials are commonly used. This type of control was originally trademarked as "U-Control" and is by far the most common control method.
The controls of a conventional 2-line/"U-Control" system consist of lead-out cables, a bellcrank, push rods and control horns. These are connected so that differential motion of the lines rotates the bellcrank, causing a pushrod to move either forward or aft. The pushrod is connected to the control surface with a control horn that moves the elevator (and flaps, if used) up and down. The pilot holds a handle to which the lines are attached. Tilting the handle with the fingers, wrist, and/or elbow motion causes the differential movement in the lines. By convention, tilting the hand so the top is closer to the pilot than the bottom results in "up" elevator, much like pulling back on a full-scale airplane control stick. Also by convention, most airplanes are flown nominally counter-clockwise as viewed from above, with the leadout cables exiting the left wing. This is not universal and some pilots fly in the opposite direction. Flying clockwise has a slight advantage in some situations because most engines run so that the torque will roll the airplane away from the pilot, increasing line tension in upright level flight.
The controls can be expanded by adding a third line that controls the throttle. The most common system for throttle control is that devised by J. Robert Smurthwait, of Baker Oregon, and is widely available. The throttle is usually a conventional carburetor as used on radio control models schemes that couple limited rudder and/or aileron, and variable leadout position are often found on carrier planes as well as elevator and flaps/
Monoline control works by twisting the single line. The pilot holds a handle with a twisted flat piece of metal on bearings in one hand, and a "bobbin" in the other. Moving bobbin towards or away from the handle twists the line. Inside the airplane, the rotating line rotates a spiral scroll with a follower. The follower moves toward and away from the pivot of the scroll, and has a pushrod attached. Then, as the scroll rotates, the pushrod moves fore and aft. The rest of the system is like the two-line system. The control of a monoline system is much less precise than a two-line system because the line itself tends to twist up before it moves the scroll, leading to a somewhat vague control response with considerable lag. It does however have the advantage of not requiring as much line tension to move the controls, and the single line has less drag than the two slightly smaller lines used in conventional two-line control.
Other control methods were devised early on to avoid having to pay royalties on the "U-Control" patent, including systems with the lines connected directly to the elevator with pulleys to change the pitch, methods that connected the lines directly to the pushrod through screw eyes, but most worked very poorly compared to conventional 2-line control.
== Power ==
Control-Line airplanes usually have a power plant of 0.049 cubic inches (0.80 cm3) to 0.60 cubic inches (9.8 cm3), although engines can be as large as .90, or may have electric power. Two-stroke glow engines are most common, but almost any form of model engine has been used, including pulse jet engines and turbojets. Control-line models tend to have very high power-to-weight ratios compared to R/C models or full-scale aircraft. The size of the engines and the models are significantly limited by the maximum line length of 70 feet (21 m) used for competition, although very long lines (as much as 150 feet) have been used on rare occasions.
The competition categories that need high power output and speed can turn at very high rotational speeds for a reciprocating engine. A 0.15 in3 (2.5 cm3) engine used in the FAI Speed event may produce as much as 3 hp (2.2 kW) at rotational speeds in the range of 45000 rpm - faster than some full-scale turbojets. The specific output is around 1200 hp/liter which is far in excess of racing motorcycle engines or Formula 1 auto racing engines. Many breakthroughs in two-stroke engine design (both model and motorcycle) can be traced back to C/L speed models, as the small size makes it easy to experiment with new designs at low cost.
Control line models tend to run a varying mix of fuel however 10% nitromethane, 20% castor oil and 70% methanol is common. Castor oil is sometimes replaced by synthetics, however as control line aircraft typically run at high throttle settings for the entire flight, castor oil generally provides better lubrication and cooling and is thus considered safer for the engine. It is however somewhat viscous and the resulting oil drag can rob some power compared to synthetic oil, and can also lead to "varnishing" of the cylinder. Some older-technology engines commonly used for control line can be very quickly damaged with typical R/C fuels because of low oil content.
Pulse jet models use gasoline, a variety of flammable liquids like acetone, methyl-ethyl-ketone, and other similar fluids. Pulse-jet models are started by applying a continuous spark device (e.g. a "buzzer coil" as used on a Fordson tractor) to a spark plug in the side of the combustion chamber, and then using a bicycle pump or pressurized air to blow air across the fuel injector and into the engine. When a flammable mixture is present in the engine, it will detonate, sending a shock wave down the tail pipe and creating suction at the intake end of the engine, sucking in more fuel/air, and creates another explosion. Once started, the engine becomes hot very quickly and no longer requires the spark. The spark box and air source are disconnected and then model launched as quickly as possible to prevent the heat generated by the engine from causing the airplane to catch fire. The engine is extremely loud in operation and cannot be muffled, and can be heard for miles under the right conditions.
The propellers used for control-line models are commonly made of wood (usually maple), fiberglass-reinforced plastic (GRP), or graphite/kevlar/fiberglass and epoxy. The propeller pitch and diameter are chosen based on the engine size, type of performance desired, and cost. A typical .61-sized piped engine uses a 3-bladed propeller around 12-13" in diameter and around 4" of pitch, and is usually made of graphite/epoxy. A .20-sized sport model might use an inexpensive 8" diameter, 4" pitch propeller made of fiberglass-reinforced plastic. The graphite stunt propellers are usually made in small production runs or even by hand, and can cost as much as $50. Small GRP sport propellers are made by injection molding and may cost as little as $2.
The fuel for the engine is usually held in a metal or plastic fuel tank, shaped so that fuel is drawn from the outside edge of the tank, as the fuel tends to be thrown to the side by centrifugal force as the airplane travels in a circle. A "clunk tank" as used in R/C is satisfactory, but dedicated tanks with wedge-shaped cross-sections are frequently used and tend to have better characteristics as the fuel runs out. A tank with a vent on the inner edge, or multiple vents, is usually called a 'suction' tank. The pressure of fuel delivery with a suction tank changes as the fuel runs out, causing the engine mixture ratio to become leaner as the flight proceeds. Tanks vented to only permit air to enter at the outside edge ("uniflow" tanks) provide constant fuel pressure over the duration of the flight and a constant mixture ratio.
Combat and some speed models use rubber tubing ("bladder" tank), baby pacifiers, or fountain pen ink bladders, inflated with fuel from a large syringe, to hold the fuel under fairly high pressure. The fuel line is pinched off to prevent fuel loss until the engine is started. The high pressure of fuel delivery permits the use of a larger intake on the engine, allowing more air flow than would otherwise be possible, and thus more power. This type of fuel delivery is by far the most steady until the fuel finally runs out.
The carburetion on most control-line engines is a simple fixed-size orifice (venturi) with only a mixture ratio adjustment. The engine can be run over a very wide range of mixtures and adjusting the needle valve can be used to adjust the engine speed over a small range. Once released, the engine runs at a more-or-less constant speed until the fuel runs out, or, if equipped, the fuel-shutoff is activated. Altering the size of the venturi used can be used to adjust the gross power. Two-stroke glow motors can be made to run in a 4-stroke mode where the engine mis-fires on every other stroke, and changes mode of firing based on load of the propeller. A tremendous degree of control over how the engine runs in flight is possible by altering the fuel contents, propeller size, pitch, and pitch distribution, venturi size, compression ratio of the engine, and the length of the tuned exhaust, if used.
== Landing gear ==
The landing gear/undercarriage on control line aircraft can vary from basic piano wire and wheels to competition models with spring-loaded shock absorption and wheel pants. Retractable landing gear is common on scale models and is occasionally used in stunt. Most speed and combat models omit the landing gear in the interest of drag and weight reduction, and are launched from hand or a "dolly".
Navy carrier models have a reinforced hook to help them catch an arresting cable on a simulated carrier deck.
== Competitions ==
Competitions for control line aircraft are held in various classes. These include speed, precision aerobatics (AKA stunt), team racing, combat, naval carrier, and scale.
For competition the lines are tested before flight with a "pull test" that varies with the model weight and category to verify that the lines and control system (primarily the bellcrank and its attachment to the rest of the model) will withstand the line tension during flight.
=== Speed (F2A) ===
Speed is divided up into different engine capacity classes and a Jet class (using pulse jet engines). As the name suggests, the idea is to have the model go as fast as possible. The model is timed over a number of laps, and the pilot must hold the handle controlling his model in a yoke on top of a pole in the center of the circle. This is in order to stop the pilot from assisting the model to go faster by increasing the line tension and leading the model (known as whipping). Monoline control systems are common in the US, but international classes require the use of two-line control. Speeds of the fastest models - Class D 0.60 cubic inches (9.8 cm3) and Jet - have in the past exceeded 220 mph (350 km/h). Current US rules limit the speeds to <200 mph (320 km/h) by requiring the use of larger lines if 200 mph (320 km/h) is exceeded. Speed models are usually launched from a "dolly" - a cart that permits a lengthy ground roll for takeoff, but drops away in the air to reduce drag. The airplane lands on a skid or belly pan.
=== Precision aerobatics (F2B) ===
Precision aerobatics consists of flying a fixed sequence of maneuvers which are judged by a panel of judges for accuracy and precision. The event was originally dubbed "stunt" and current participants refer to it that way informally. Factors such as height of the maneuver bottoms, shapes, corner radius, and other factors are considered. The judges at large competitions are typically trained for several days on how to assess the maneuvers and apply a score. Judging well is generally considered at least as difficult as flying in competition.
Stunt models tend to be among the larger control line models, wings usually spanning from around 45–60 inches (1.1–1.5 m). Top competition models have been traditionally powered by a two-stroke engine in the 0.35 cubic inches (5.7 cm3) to 0.60 cubic inches (9.8 cm3) range, with four-stroke model engines and electric power also becoming popular as power sources. The airplanes, while possessing high thrust-to-weight ratios by full-scale standards (usually at least 1:1), are intended to fly quite slowly to enhance pilot control, typically around 55–60 mph (89–97 km/h), with a single lap of the circle taking around 5.5 seconds.
Engines are commonly set to increase their power output when under load. This permits low speeds but very good speed stability, so the climb performance is excellent. The original scheme used was to take advantage of the tendency of a nominally two-stroke glow engine to change from running in a four-stroke when set with extremely rich mixtures, to running in a two-stroke when the load increases. This is called a "4-2 break". More recently, tuned exhausts have been used to provide regulation of the speed in flight. Combined with propellers of relatively low pitch, this has permitted much more control over the engine's speed and power response to maneuvering. Electric system contain feedback control system that govern the RPM of the motor to a constant value regardless of load.
Most competitive aircraft are fitted with flaps on the wings, which work in conjunction with the elevator to increase the pitch maneuverability. When up-elevator is applied, the flaps on the wings go down, and vice versa. This results in the wing, which is otherwise of a symmetrical section, to be cambered in the direction needed to enhance maneuvering. Aircraft without flaps can be flown successfully and are typically simpler, but flapped models typically fly more smoothly and can be heavier. Some of the simpler stunt models make excellent control-line trainers, as the predictable control response, low speed, and strong line tension make them easy to fly successfully.
Stunt models are often beautifully painted. Stunt rules include the appearance of the model in the score, and creating the most perfectly finished and attractive models is a competition in and of itself. A "Concours d'Elegance" award is voted on by the pilots at the Academy of Model Aeronautics' US Nationals in Muncie, Indiana for the prettiest airplane, and is very highly prized.
Stunt is flown in many countries, with World Championships being held on alternate years. These are open for any flier who makes his or her respective national team. Competition at the highest levels (National or World Championships) can take many years or decades of practice to master the intricacies of designing, building, finishing, adjusting, and controlling the power of the airplanes, in addition to the high piloting skills. Many top competitive pilots have coaches.
Many competitions separate pilots into 4 different skill levels (beginner, intermediate, advanced and expert) allowing pilots to compete against other pilots of similar skill levels.
=== "Old time" stunt ===
Much like the "old timer" vintage design movement in free flight aeromodeling, several specialized classes of Stunt include "Old Time Stunt" where simpler maneuvers are performed with a model that was designed before a specific date (Pre 1953 per US rules) and "Classic" stunt which uses the current stunt "pattern" of maneuvers and airplanes designed prior to 1970.
=== Racing (F2C) ===
Racing is an event for two-person teams—the pilot and the pit crew. There are various racing classes of various levels of difficulty: F2C (the class flown internationally and at World Championships), Goodyear (semi-scale models of 'Goodyear era' full-size racers), Vintage classes and so on.
The basic idea of all the events is that a number of models (up to three) fly together, aiming to complete a given number of laps before any of the others. The model is also required to make multiple pit stops during the race, where it is refueled, the engine restarted, and the model re-launched. This is the job of the pit crew. There are rules describing how the pilots must walk around each other, and how to pass (harder than one might think, as each model is on the end of a pair of control lines and travelling as fast as 140 mph). Pit stops require that the model be refueled and restarted - which can be a problem with a very hot racing engines. The best FAI Team Race pit stops take around 2–3 seconds for the pilot to cut the motor and land, allowing the pit-man to catch the model which only moments ago was flying at 140 mph (230 km/h), fill the tank with 7cc of model fuel from a pressurized tank, adjust the engine mixture and compression if needed, restart, and relaunch the model.
=== Combat (F2D) ===
Combat is an event where two pilots "dogfight" for cuts on their opponent's streamer, for a perscribed amount of time called the "Match". Models are fast and highly maneuverable typically of flying-wing types, which chase each other around the sky at speeds in excess of 100 mph (160 km/h). Despite deliberate mid-airs being banned, the carnage rate is high, and pilots commonly bring 10 or more models to a competition.
In the US there are three A.M.A. Events, which are Fast Combat (up to a .36 c.i.d. engine is allowed), Speed Limit Combat and 1/2A (up to a .051 c.i.d. engine is allowed) Combat which can be flown high or low performance. In any event where the model exceeds 75 mph, the model must be equipped with a fuel shut-off, which shuts the engine off, when the control lines are cut. Combat may be held as a kill event, or a no-kill event. A kill is scored when one competitor cuts the string that holds the streamer (of his opponent), to the plane, and is an instant win of the match. Cutting the streamer however results in an award of points. In No-Kill combat cutting the string is the same as cutting the streamer and only points are awarded. There are a lot of unofficial events held throughout the US, such as Northwest 80 mph Combat, WWII combat, Formula GX Combat, 15 Fast and the like. Combat requires perhaps the fastest reflexes of any CL event, and pilots skilled at combat typically compete well in other events like Stunt or Racing. Combat has been described as a team sport, with the pilot relying on up to a two-person pit crew. As may be imagined, with two pilots not cooperating with each other, line tangles can happen suddenly, and crash landings are common. Despite the high speed of the models, most combat models are made to be quite robust, and when time allows may hit the ground and suffer little damage and be relaunched. Although for the Speed limit events up to a .40 c.i.d. engine may be used, for the AMA fast event, there is only one manufacture of a high performance .36, that being Henry Nelson. A well-tuned and fueled Nelson 36 may achieve 25,000 r.p.m. while statically running on the ground and gain significant r.p.m. in the air. Current 1/2A engines in use are all from former soviet republics and include the Fora and Cyclon, both of which will run well above 33,000 r.p.m. In all the AMA events pressure fed fuel systems are allowed and virtually every combat plane is equipped with a fuel "Bladder". The Fuel Bladder gives the most consistent fuel feed while the aircraft is undergoing sudden and violent maneuvers, typical of flying in a match.
F2D combat - the international class for combat - is most popular in Russia and Europe, where some countries have professional or semi-professional teams. Russia and the former Soviet countries are currently the main producers of world-class equipment for this sport, including engines. Their combination of the latest engineering and design, with exotic metallurgy and experience, results in combat engines which reliably turn 32,000 rpm, and can be restarted easily in the event of a crash. Requiring lightning-fast reflexes, combat has frequently been used as a training-ground and/or hobby for many commercial and military pilots .
=== Diesel (F2E/F2F) ===
F2E diesel combat -
F2F diesel team -
=== Electric (F2G) ===
=== Navy carrier ===
Navy carrier is an event where semi-scale models of real naval aircraft are flown. The event replicates the requirements of full-scale carrier aircraft, which need high speed for combat performance, and low speeds and toughness for safe carrier landings. Takeoff and landing are from a simulated aircraft carrier deck, with arrestor wires.
The aim of the flight is to complete a number of fast laps, flown as quickly as possible, followed by a number of slow laps, flown as slowly as possible. This is followed by the carrier deck landing, attempting to snag the arrestor wire. The score depends on the difference of the high and low speed, and the arrested landing. Carrier models usually have a third control line, worked by a finger trigger in the handle. This line allows the throttle setting of the engine to be controlled and the arrestor hook to be dropped. Often, a carrier model will have flaps. Unlike a stunt model, however these flaps are worked separately from the elevator. A large amount of flap is usually applied during the slow laps, and a large amount of line sweep is added to yaw the model out of the circle to maintain line tension at the very low ground speeds. Low speeds are frequently no faster than a fast walk, and when aimed into a light breeze forward motion may stop completely with the model hanging at a very high angle of attack from the propeller.
=== Scale ===
Scale is an event where an accurate scale model of a real aircraft is flown. Scoring is based on static judging of how closely the aircraft resembles the full-size prototype and on the flight performance. Extra points are often awarded for "working" features of the model, such as a retractable landing gear, droppable bombs, and other functions or operations. The number of features used to be limited by the number of lines that could be practically used to mechanically control them.
Some complex scale models use a fly-by-wire approach to allow a multitude of extra working features. A radio-control transmitter's encoder unit can be adapted, with no RF signal board present, to send its control signals along insulated control lines, instead of broadcasting them using radio frequencies. If signals are sent down the lines, the normal serial multiplexing of the control signals by such an adapted RC transmitter's encoder unit, solely sending those signals along the usual duo or trio of control lines, gets picked up by decoding gear in the model - usually adapted from an RC receiver, without an RF "front end" section - and permits many functions to be controlled without the use of additional lines. Standard servos can then be used in the model. From 2013, in the USA, the radio control "over the airwaves" of any moveable feature of control-line Scale or Carrier models (except the elevator) is permitted - this may spread to Europe and beyond in time.
== Safety ==
Control-line flying is generally quite safe when all prescribed safety measures are followed. The airplane is constrained to fly in a circle, which is generally marked. A pilots' circle is also provided, so as long as the pilot stays in the pilot's circle and everyone else is outside the outer circle, the flying model can hit no one. In most competition categories, a "safety thong" connecting the control handle to the pilot's wrist is also required, so if the pilot inadvertently releases the handle, the airplane cannot fly outside the circle (and, frequently crashes, safely for others if not the airplane, when control is lost). The lines, handle, and control system are subjected to a "pull test" before flight to ensure that they are in good shape with some significant margin. For example, the pull test is around 40 lb (18 kg) for a 4 lb (1.8 kg) Stunt model (a 10G load), and the in-flight pull is around 10 lb (4.5 kg). This provides a 2x margin of safety even if one line should fail. One failed line immediately moves the elevator to the extreme of its movement, which almost always results in a crash, safely in the circle. Other categories of model are tested in a similar way, with the loads set to correspond to the expected speeds with a safety margin around a factor of 4.
Combat models, albeit very rarely, may have their lines cut or otherwise broken by the other airplane, and can fly outside the circle. Most combat competition today requires that the airplane be equipped with a device that shuts off fuel to the engine if the lines are cut. This can work by either using the centripetal acceleration to keep the shutoff from pinching the line, or by using the line tension to hold the pinch-off device open. This way, the engine is not running and tends to decelerate very quickly instead of accelerating quickly as it would otherwise (since the drag of the lines is removed). This technique has proved to be very effective in practice. Many combat events also require the engine to be attached to the bellcrank with a cable, so that a mid-air collision will not result in the engine flying off and into the spectators. Competitors in some forms of combat competition are also required to wear helmets.
Another potential safety issue is overhead power lines. Contact with power lines, or approaching high-tension power lines, is potentially fatal and must be avoided. The use of non-metallic lines may reduce the risk of electrocution, but still a margin of 150 from the plane to power lines, is mandated in the AMA safety code.
Sometimes models with landing gear are flown by using a "stooge" that holds the airplane until released by the pilot from the center, usually with a spring-loaded pin pulled with a string. This allows a pilot to practice with no helper, and is common with stunt fliers trying to practice extensively. This has the potential to be dangerous if the pilot fails to properly reset the stooge, the wire connecting the stooge to the airplane (usually attached to the tail wheel) breaks, the stooge moves under the thrust/vibration of the engines, or the pilot's feet get tangled in the stooge release line.
The other safety issues are common with other powered model categories. Hand-starting very powerful engines, with very sharp propellers, can be quite hazardous. An electric starter can be used, but can have negative effects on the engines due to engines not being designed to take that kind of force pushing the crank shaft back. One such method is the "back-bump" method, where the engine is choked and flipped through with no battery attached to create favorable starting conditions. Once prepared, all that is necessary is to rock the engine backwards so that it coasts up to compression, and if done correctly, starts forwards. This provides time to move the hand out of the way and the fingers are not in contact with the propeller or spinner when the engine starts. Care must be taken even choking the engine as modern engines with their accurate piston/cylinder fit can "bump" or even start without the battery attached. Once the propeller is rotating, extreme care must be taken when preparing for flight and adjusting the engine. A starting accident frequently results in a small cut to the finger, but once the engine is at full speed any injury that is encountered is likely to be quite severe.
Pulse jet engines get extremely hot once started, and use very volatile fuels like gasoline or methyl-ethyl-ketone (as contrasted to relatively benign, although flammable, glow engine fuel). Contact of any type with the tailpipe of the engine is certain to result in severe burns, as the engine reaches red-hot temperatures in seconds. The airplane itself needs some sort of insulation to prevent catching fire on the ground before forward motion provides cooling air, and fully enclosed engines can set the airplane on fire after landing. The airplane should be launched as soon as possible after the engine starts to prevent heat buildup. The spark unit used for starting can also deliver a substantial electrical shock. A fire extinguisher should be at hand at all times when operating the engine. The engine is exceptionally loud when operating and should be operated with hearing protection to prevent damage.
== See also ==
Fédération Aéronautique Internationale
Model aircraft
Round-the-pole flying
Tether cars
Cox Models
Cox model engine
== References ==
=== Organizations ===
AMA - Academy of Model Aeronautics USA
MAAC - Model Aeronautics Association of Canada
CLAPA - Control Line Aerobatic Pilots Association UK
FAI - Fédération Aéronautique Internationale
MAAA - Model Aeronautical Association of Australia
PAMPA - Precision Aerobatics Model Pilots Association USA
MACA - Miniature Aircraft Combat Association USA
NCLRA National Control Line Racing Association USA
CFA - Combat Flyers Association UK
CLP - F2 - Control Line Portugal PT
=== Non Commercial ===
Australian Control Line Nostalgia
Australian Control Line Forum
Barton Model Flying Club Control Line Forum
Control Line Aircraft Society NSW
Control Line Combat
Cox Model Engine Museum
Kuringai Model Flying Club
Stuka Stunt Works
Stuka Stunt Control Line Forums
StuntHangar Control Line Forums
Taiwan Control Line Forum
Scale Control Line Models UK
Flying Lines, Daily News of Pacific Northwest Control Line Model Aviation
Dutch control line site
Zborcircular/Control Line Stunt
Circlemasters Flying Club Milwaukee Wisconsin
Dutch control line site
Tulsa Oklahoma Club | Wikipedia/Control_line |
A model engine is a small internal combustion engine typically used to power a radio-controlled aircraft, radio-controlled car, radio-controlled boat, free flight, control line aircraft, or ground-running tether car model.
Because of the square–cube law, the behaviour of many engines does not always scale up or down at the same rate as the machine's size; usually at best causing a dramatic loss of power or efficiency, and at worst causing them not to work at all. Methanol and nitromethane are common fuels.
== Overview ==
The fully functional, albeit small, engines vary from the most common single-cylinder two-stroke to the exotic single and multiple-cylinder four-stroke, the latter taking shape in boxer, v-twin, inline and radial form, a few Wankel engine designs are also used. Most model engines run on a blend of methanol, nitromethane, and lubricant (either castor or synthetic oil).
Two-stroke model engines, most often designed since 1970 with Schnuerle porting for best performance, range in typical size from .12 cubic inches (2 cubic centimeters) to 1.2 ci (19.6 cc) and generate between .5 horsepower (370 watts) to 5 hp (3.7 kW), can get as small as .010 ci (.16 cc) and as large as 3-4 ci (49–66 cc). Four-stroke model engines have been made in sizes as small as 0.20 in3 (3.3 cc) for the smallest single-cylinder models, all the way up to 3.05 in3 (50 cc) for the largest size for single-cylinder units, with twin- and multi-cylinder engines on the market being as small as 10 cc for opposed-cylinder twins, while going somewhat larger in size than 50 cc, and even upwards to well above 200 cc for some model boxer opposed-piston, inline and radial engines. While the methanol and nitromethane blended "glow fuel" engines are the most common, many larger (especially above 15 cc/0.90 ci displacement) model engines, both two-stroke and a growing number of four-stroke examples are spark ignition, and are primarily fueled with gasoline — with some examples of both two and four-stroke glow plug-designed methanol aeromodeling engines capable, with aftermarket upgrades, to having battery-powered, electronically controlled spark ignition systems replacing the glow plugs normally used. Model engines refitted in such a manner often run more efficiently on methanol-based glow plug engine fuels, often with the ability to exclude the use of nitromethane altogether in their fuel formulas.
This article concerns itself with the methanol engines; gasoline-powered model engines are similar to those built for use in string trimmers, chainsaws, and other yard equipment, unless they happen to be purpose-built for aeromodeling use, being especially true for four-stroke gasoline-fueled model engines. Such engines usually use a fuel that contains a small percentage of motor oil as a two-stroke engine uses for lubrication purposes, as most model four-stroke engines — be they glow plug or spark ignition — have no built-in reservoir for motor oil in their crankcase or engine block design.
The majority of model engines have used, and continue to use, the two-stroke cycle principle to avoid needing valves in the combustion chamber, but a growing number of model engines use the four-stroke cycle design instead. Both reed valve and rotary valve-type two-strokes are common, with four-stroke model engines using either conventional poppet valve, and rotary valve formats for induction and exhaust.
The engine shown to the right has its carburetor in the center of the zinc alloy casting to the left. (It uses a flow restriction, like the choke on an old car engine, because the venturi effect is not effective on such a small scale.) The valve reed, cross shaped above its retainer spring, is still beryllium copper alloy, in this old engine. The glow plug is built into the cylinder head. Large production volume makes it possible to use a machined cylinder and an extruded crank case (cut away by hand in the example shown). These Cox Bee reed valve engines are notable for their low cost and ability to survive crashes. The components of the engine shown come from several different engines.
== Comparison of engines ==
Images of a glowplug engine and a "diesel" engine are shown below for comparison. The most obvious external difference is seen on top of the cylinder head. The glowplug engine's glow plug has a pinlike terminal for its center contact, which is an electrical connector for the glowplug. The "diesel" engine has a T-bar which is used for adjusting the compression. The cylindrical object behind the glowplug engine is an exhaust silencer or muffler.
== Glowplug engines ==
Glow plugs are used for starting as well as continuing the power cycle. The glow plug consists of a
durable, mostly platinum, helically wound wire filament, within a cylindrical pocket in the plug body, exposed to the combustion chamber. A small direct current voltage (around 1.5 volts) is applied to the glow plug, the engine is then started, and the voltage is removed. The burning of the fuel/air mixture in a glow-plug model engine, which requires methanol for the glow plug to work in the first place, and sometimes with the use of nitromethane for greater power output and steadier idle, occurs due to the catalytic reaction of the methanol vapor to the presence of the platinum in the filament, thus causing the ignition. This keeps the plug's filament glowing hot, and allows it to ignite the next charge.
Since the ignition timing is not controlled electrically, as in a spark ignition engine or by fuel injection, as in an ordinary diesel, it must be adjusted by the richness of the mixture, the ratio of nitromethane to methanol, the compression ratio, the cooling of the cylinder head, the type of glow plug, etc. A richer mixture will tend to cool the filament and so retard ignition, slowing the engine, and a rich mixture also eases starting. After starting the engine can easily be leaned (by adjusting a needle valve in the spraybar) to obtain maximum power. Glowplug engines are also known as nitro engines. Nitro engines require a 1.5 volt ignitor to light the glow plug in the heat sink. Once primed, pulling the starter with the ignitor in will start the engine.
== Diesel engines ==
Diesel engines are an alternative to methanol glow plug engines. These "diesels" run on a mixture of kerosene, ether, castor oil or vegetable oil, and cetane or amyl nitrate booster. Despite their name, their use of compression ignition, and the use of a kerosene fuel that is similar to diesel, model diesels share very little with full-size diesel engines.
Full-size diesel engines, such as those found in a truck, are fuel injected and either two-stroke or four-stroke. They use compression ignition to ignite the mixture: the compression within the cylinder heats the inlet charge sufficiently to cause ignition, without requiring an applied ignition source. A fundamental feature of such engines, unlike petrol (gasoline) engines, is that they draw in air alone and the fuel is only mixed by being injected into the combustion chamber separately. Model diesel engines are instead a carbureted two-stroke using the crankcase for compression. The carburetor supplies a mixture of fuel and air into the engine, with the proportions kept fairly constant and their total volume throttled to control the engine power.
Apart from sharing the diesel's use of compression ignition, their construction has more in common with a small two-stroke motorcycle or lawnmower engine. In addition to this, model diesels have variable compression ratios. This variable compression is achieved by a "contra-piston", at the top of the cylinder, which can be adjusted by a screwed "T-bar". The swept volume of the engine remains the same, but as the volume of the combustion chamber at top dead centre is changed by adjusting the contra-piston, the compression ratio (swept volume + combustion chamber / combustion chamber) changes accordingly.
Model diesels are found to produce more torque than glow engines of the same displacement, and are thought to get better fuel efficiency, because the same power is produced at a lower rpm, and in a smaller displacement engine. However, the specific power may not be significantly superior to a glow engine, due to the heavier construction needed to assure that the engine can withstand the much higher compression ratio, sometimes reaching 30:1. Diesels also run significantly quieter, due to the more rapid combustion, unlike two-stroke glow engines, in which combustion may still be occurring when the exhaust ports are uncovered, causing a significant amount of noise.
Recent developments in model engineering have produced true diesel model engines, with a traditional injector and injector pump, and these engines operate in the same way as a large diesel engine.
== See also ==
Four-stroking
Glow plug (model engine)
Glow fuel
Nitro engine
Schnuerle porting, used on model two-stroke engines since the 1970s
=== Makers ===
Bullitt Engines
Cox Model Engines
Enya Model Engines (two and four-stroke model engines)
FOX Manufacturing
FX Royal Racing Engines
K&B Manufacturing
Laser Engines
LRP electronic (rebranded OS Engines)
Mantua Models
GAUI GPOWER
MECOA
Motori Cipolla
Ninja Engine
Novarossi
nVision
O.S. Engines (two and four-stroke model engines)
OPS (engine)
Picco Micromotori
RB Products
rcvengines
Reds Racing
Saito Seisakusho (four-stroke and model steam engine specialist)
Team Orion
Thunder Tiger
Webra
Yamada Engines (YS) (two and four-stroke model engines)
== References ==
== External links ==
K&B Manufacturing
Yamada Engines
Saito Seisakusho Archived 2014-02-03 at the Wayback Machine
WEBRA
FOX Manufacturing
MECOA
COX Hobbies | Wikipedia/Model_engine |
A radio-controlled aircraft (often called RC aircraft or RC plane) is a small flying machine that is radio controlled by an operator on the ground using a hand-held radio transmitter. The transmitter continuously communicates with a receiver within the craft that sends signals to servomechanisms (servos) which move the control surfaces based on the position of joysticks on the transmitter. The control surfaces, in turn, directly affect the orientation of the plane.
Flying RC aircraft as a hobby grew substantially from the 2000s with improvements in the cost, weight, performance, and capabilities of motors, batteries and electronics. Scientific, government, and military organizations are also using RC aircraft for experiments, gathering weather readings, aerodynamic modeling, and testing. A wide variety of models, parts, and styles is available for the DIY market.
Nowadays, distinct from recreational civilian aeromodelling activities, unmanned aerial vehicle (drones) or spy planes add a video, GPS or autonomous feature, enabling instrumental RLOS or BLOS capabilities, which are used for public service (firefighting, disaster recovery, etc.) or commercial purposes, and if in the service of a military or paramilitary, may be armed.
== History ==
The earliest examples of electronically guided model aircraft were hydrogen-filled model airships of the late 19th century. They were flown as a music hall act around theater auditoriums using a basic form of spark-emitted radio signal.
The British drone weapons in 1917 and 1918 evolved and their development continued through the work of the Royal Aircraft Establishment resulting in the fleet of over 400 Queen Bee UAV Target Aircraft in the 1930s.
During World War II, the U.S. Army and Navy used radio controlled planes called Radioplanes as artillery target drones.
The National Model Aviation Museum located in Muncie, Indiana hosts the world's largest collection of RC aviation history. They display models from every era of RC donated by the RC community around the world. They also have kit plans (aircraft blueprints) that RC pilots can purchase to build models from every era. The museum is located on the same grounds that the Academy of Model Aeronautics main office is located.
== Types ==
There are many types of radio-controlled aircraft. For beginning hobbyists, there are park flyers and trainers. For more experienced pilots there are glow plug engine, electric powered and sailplane aircraft. For expert flyers, jets, pylon racers, VTOL planes, helicopters, autogyros, 3D aircraft, and other high-end competition aircraft provide adequate challenge. Some models are made to look and operate like a bird instead. Replicating historic and little known types and makes of full-size aircraft as "flying scale" models, which are also possible with control line and free flight types of model aircraft, actually reach their maximum realism and behavior when built for radio-control flying.
=== Radio-control scale aircraft modeling ===
Perhaps the most realistic form of aeromodeling, in its main purpose to replicate full-scale aircraft designs from aviation history, for testing of future aviation designs, or even to realize never-built "proposed" aircraft, is that of radio-control scale aeromodeling, as the most practical way to re-create "vintage" full-scale aircraft designs for flight once more, from long ago. RC Scale model aircraft can be of any type of steerable airship lighter-than-air (LTA) aviation craft, or more normally, of the heavier-than-air fixed wing glider/sailplane, fixed-wing single or multi-engine aircraft, or rotary-wing aircraft such as autogyros or helicopters.
Full-scale aircraft designs from every era of aviation, from the "Pioneer Era" and World War I's start, through to the 21st century, have been modeled as radio-control scale model aircraft. Builders of RC Scale aircraft can enjoy the challenge of creating a controllable, miniature aircraft that merely "looks" like the full scale original in the air with no "fine details", such as a detailed cockpit, or seriously replicate many operable features of a selected full scale aircraft design, even down to having operable cable-connected flight control surfaces, illuminated navigation lighting on the aircraft's exterior, realistically retracting landing gear, etc. if the full-sized aircraft possessed such features as part of its design.
Various scale sizes of RC scale aircraft have been built in the decades since modern digital-proportional, miniaturized RC gear came on the market in the 1960s, and everything from indoor-flyable electric powered RC Scale models, to "giant scale" RC Scale models, in scale size ranges that usually run from 20% to 25%, and upwards to 30 to 50% size of some smaller full scale aircraft designs, that can replicate some of the actual flight characteristics of the full scale aircraft they are based on, have been enjoyed, and continue to be built and flown, in sanctioned competition and for personal pleasure, as part of the RC scale aeromodelling hobby.
=== Sailplanes and gliders ===
Gliders are planes that do not typically have any type of propulsion. They can be towed into the air by use of another aircraft with an engine, and once at a high altitude, the glider can release from the tow rope. Unpowered glider flight must be sustained through exploitation of the natural lift produced from thermals or wind hitting a slope. Dynamic soaring is another popular way of providing energy to gliders that is becoming more and more common. However, even conventional slope soaring gliders are capable of achieving speeds comparable with similar sized powered craft.
Gliders are typically partial to slow flying and have high aspect ratio, as well as very low wing loading (weight to wing area ratio). Two and three-channel gliders which use only rudder control for steering and dihedral or polyhedral wing shape to automatically counteract rolling are popular as training craft, due to their ability to fly very slowly and high tolerance to error.
Powered gliders have recently seen an increase in popularity. By combining the efficient wing size and wide speed envelope of a glider airframe with an electric motor, it is possible to achieve long flight times and high carrying capacity, as well as glide in any suitable location regardless of thermals or lift. A common method of maximising flight duration is to quickly fly a powered glider upwards to a chosen altitude and descending in an unpowered glide. Folding propellers which reduce drag (as well as the risk of breaking the propeller) are standard. Powered gliders built with stability in mind and capable of aerobatics, high speed flight and sustained vertical flight are classified as 'Hot-liners'. 'Warm-liners' are powered craft with similar abilities but less extreme thrust capability.
=== Jets ===
Jets commonly use a micro turbine or ducted fan to power them. Most airframes are constructed from fiber glass and carbon fiber. For electric powered flight which are usually powered by electric ducted fans, may be made of styrofoam. Inside the aircraft, wooden spars reinforce the body to make a rigid airframe. They also have kevlar fuel tanks for the Jet A fuel that they run on. Most micro turbines start with propane, burn for a few seconds before introducing the jet fuel by solenoid. These aircraft can often reach speeds in excess of 320 km/h (200 mph). The high speed requires greater skill to operate.
In the U.S.A. the FAA restricts flying of such aircraft to approved AMA Academy of Model Aeronautics sites, where only certified turbine pilots may fly. Also, the AMA requires model aviation enthusiasts who wish to operate miniature gas turbine powered RC model aircraft, to be certified in the operation of the type of gas turbine engine, and all aspects of safety in operating such a turbine-powered model aircraft, that they need to know in flying their model. Some military bases allow such high tech aircraft to fly within limited airspace such as Kaneohe Marine base in Hawaii, and Whidbey Island NAS in Washington State.
An average turbine aircraft will cost between US$150–US$10,000 with more than US$20,000 all-up becoming more common. Many manufactures sell airframes such as Yellow Aircraft and Skymaster. Turbines are produced from The Netherlands (AMT) to Mexico (Artes Jets). The average microturbine will cost between US$2500 and US$5000 depending on engine output.
Smaller turbines put out about 12 lbf (53 N) of thrust, while larger microturbines can put out as much as 45 lbf (200 N) of thrust. Radio-control jets require an onboard FADEC (full authority digital engine control) controller; this controls the turbine, as on a full-size aircraft. RC jets also require electrical power. Most have a lithium polymer (LiPo) battery pack at 8–12 volts that controls the FADEC. There is also a LiPo for the onboard servos that control ailerons, elevator, rudder, flaps and landing gear.
Of much less complexity are the types of RC jet aircraft that actually use an electric motor-driven ducted fan instead to power the aircraft. So called "EDF" models can be of much smaller size, and only need the same electronic speed controller and rechargeable battery technology as propeller-driven RC electric powered aircraft use.
Radio-controlled jet aircraft are produced in the colors of various airlines. Among the most popular airline liveries used by modelers are those of American, Singapore, Pan Am, Etihad and Delta Airlines.
=== Sports planes ===
Sports planes are planes capable of performing aerobatic maneuvers involving aircraft attitudes that are not used in normal flight. Typical aerobatic maneuvers include inside loop, outside loop, Immelmann turn, inverted flight, stall turn, slow roll and Cuban 8.
=== 3D planes ===
3D flight is a type of flying in which model aircraft have a thrust-to-weight ratio of more than 1:1 (typically 1.5:1 or more), large control surfaces with extreme throws, low weight compared to other models of same size and relatively low wing loadings. Simply put, 3D flight is the art of flying a plane below its stall speed (the speed at which the wings of the plane can no longer generate enough lift to keep the plane in the air).
These elements allow for spectacular aerobatics such as hovering, 'harriers', torque rolling, blenders, rolling circles, flat spins, and more; maneuvers that are performed below the stall speed of the model. The type of flying could be referred to as 'on the prop' as opposed to 'on the wing', which would describe more conventional flight patterns that make more use of the lifting surfaces of the plane.
3D has created a huge market for electric indoor 'profile' types similar to the Ikarus 'Shockflyers' designed to be able to fly inside a gym or outside in little wind. These generally make use of small brushless motors (often outrunners, but also geared inrunners) and lithium polymer batteries (Li-Po). There are also many larger 3D designs designed for two and four stroke glow engines, two stroke gas engines and large electric power systems.
=== Pylon racers ===
Racers are small propeller-driven aircraft that race around a 2, 3, or 4 pylon track. They tend to be hard to see and can often go over 240 km/h (150 mph), though some people do pylon races with much slower aircraft. Several different types of aircraft are raced across the world, those flown primarily in the US are; Q500 (424 or ARPRA, and 428), and Q40.
424 is designed as a starting point into the world of pylon racing. Inexpensive (under US$200 for the airframe) kits with wing areas of 3,200 square centimetres (500 sq in) are flown with 0.40" size engines that can be purchased for less than US$100. The goal is for the planes to be not only inexpensive, but closely matched in performance. This places the emphasis on good piloting. APRA is a version of 424 with specific rules designed for consistency.
428 aircraft are similar to 424 in appearance. The difference is in engine performance and construction. The planes are primarily made of fiberglass with composites used at high load points. Wings are often hollow to save weight. (All aircraft must meet a minimum weight. A lighter wing moves more of the weight closer to the center of gravity. This requires less control deflection and its resulting drag to change the planes attitude.) They also use .40 cu in size engines but unlike 424 they are much more expensive. They have been designed to put out the maximum amount of power at a specific RPM using a specific fuel. Nelson manufactures the most predominantly used engine. Speeds are very fast in this class with planes capable of reaching 265 km/h (165 mph).
Q40 is the highpoint of pylon racing, as their aircraft resemble full-size race planes. They are not limited to the simple shapes that Q500 planes are, which have much cleaner aerodynamics and less wing area. They use the same basic Nelson engine used in 428, but the engine is tuned to turn a much smaller prop at a much higher rpm. These planes can fly in excess of 320 km/h (200 mph) on the course. Because of their limited wing area however, Q40 planes must fly a larger arc around the pylons to conserve energy. Although faster, they ultimately fly a larger course. The best times for a 10 lap 3 pylon Q40 race are very close to the same in 428.
F3D is the fastest class in "glow-powered" pylon racing. These planes reach speeds of over 100 m/s (225 mph) on the race course. The race course is the same as in AMA 424 or AMA 428, but there are few limits on the airframe and engine. The maximum engine displacement is .40ci, ignition must be a glowplug, fuel must be 80% methanol/20% castor oil, all else is free. There are airframe limits on wing thickness, fuselage dimensions, and weight for safety reasons.
All this results in an extreme racing class, where R&D, trial and error, science, and piloting skills meet to create a very fast and exciting sport.
=== Park flyers and micro planes ===
Park flyers are small, primarily electric-powered planes, so named because their size enables some of them to be operated within the confines of a large public park. The smallest park flyers are called micro planes, and are slow and docile enough to fly within an enclosed area such as a gymnasium or even a living room.
Because of their size and relative ease of setup, ready-to-fly park flyers are among the most popular class of RC aircraft for beginners and advanced pilots alike. Advanced electronic and material technologies have even brought forth high-performance, park flyer sized "3D-flyers", or fully aerobatic aircraft capable of extreme high g maneuvers and even nose-up hovering. Once the exclusive realm of giant scale, 3D flight is now possible both indoors and out with certain park flyer aircraft.
Park flyers have created an inexpensive and convenient way for beginners to get involved in the hobby of RC flight. The modern materials used in the simple construction of these aircraft make field repairs possible even after significant crash damage. Their small size and quiet operation make it possible to fly them in residential areas.
=== Helicopters ===
Radio-controlled helicopters, although often grouped with RC aircraft, are in a class of their own due to the vast differences in construction, aerodynamics and flight training. Hobbyists will often venture from planes, to jets and to helicopters as they enjoy the challenges, excitement and satisfaction of flying different types of aircraft. Some radio-controlled helicopters have photo or video cameras installed and are used for aerial imaging or surveillance. Newer "3d" radio-control helicopters can fly inverted with the advent of advanced swash heads, and servo linkage that enables the pilot to immediately reverse the pitch of the blades, creating a reverse in thrust.
=== Flying bird models, or ornithopters ===
Some RC models take their inspiration from nature. These may be gliders made to look like a real bird, but more often they actually fly by flapping wings. Spectators are often surprised to see that such a model can really fly. These factors as well as the added building challenge add to the enjoyment of flying bird models, though some ARF (almost-ready-to-fly) models are available. Flapping-wing models are also known as ornithopters, the technical name for an aircraft whose driving airfoils oscillate instead of rotate.
=== Toy-class RC ===
Since about 2004, new, more sophisticated toy RC airplanes, helicopters, and ornithopters have been appearing on toy store shelves. This new category of toy RC distinguishes itself by:
Proportional (vs. "on-off") throttle control which is critical for preventing the excitation of phugoid oscillation ("porpoising") whenever a throttle change is made. It also allows for manageable and steady altitude control and reduction of altitude loss in turns.
LiPo batteries for light weight and long flight time.
EPP (Expanded Polypropylene) foam construction making them virtually indestructible in normal use.
Low flying speed and typically rear-mounted propeller(s) make them less harmful when crashing into people and property.
Stable spiral mode resulting in simple turning control where "rudder" input results in a steady bank angle rather than a steady roll rate.
As of 2013, the toy class RC airplane typically has no elevator control. This is to manage costs, but it also allows for simplicity of control by unsophisticated users of all ages. The downside of lack of elevator control is a tendency for the airplane to phugoid. To damp the phugoid oscillation naturally, the planes are designed with high drag which reduces flight performance and flying time. The lack of elevator control also prevents the ability to "pull back" during turns to prevent altitude loss and speed increase.
Costs range from 20 to US$40. Crashes are common and inconsequential. Throttle control and turning reversal (when flying toward the pilot) rapidly become second-nature, giving a significant advantage when learning to fly a more costly hobby class RC aircraft.
== Video piloting (first-person view or FPV) ==
First-person view (FPV) flight is a type of remote-control flying and a distinguishing feature of a drone. It involves mounting a small video camera and television transmitter on an RC aircraft and flying by means of a live video down-link, commonly displayed on video goggles or a portable LCD screen. When flying FPV, the pilot sees from the aircraft's perspective, and does not even have to look at the model. As a result, FPV aircraft can be flown well beyond visual range, limited only by the range of the remote control, video transmitter and endurance of the aircraft.
Video transmitters typically operate at a power level between 200 mW and 2500 mW. The most common frequencies used for video transmission are 900 MHz, 1.2 GHz, 2.4 GHz, and 5.8 GHz. Specialized long-range UHF control systems operating at 433 MHz (for amateur radio licensees only) or 869 MHz are commonly used to achieve greater control range, while the use of directional, high-gain antennas increases video range. Sophisticated setups are capable of achieving a range of 20–30 miles or more. FPV aircraft are frequently used for aerial photography and videography, and many videos of FPV flights can be found on video sites such as YouTube and Vimeo.
A basic FPV system consists of a camera, video transmitter, video receiver, and a display. More advanced setups commonly add a flight controller, including an on-screen display (OSD), auto-stabilizer and return-to-home (RTL) functions. An RTL function is usually applied with a failsafe in order to allow the aircraft to fly back to its home point on its own if the signal is lost. Some advanced controllers can also navigate the drone using GPS. On-board cameras can be equipped with a pan and tilt mount, which when coupled with video goggles and "head tracking" devices, creates a first-person experience, as if the pilot was actually sitting in the cockpit of the RC aircraft.
Both helicopter, multiple rotors and fixed-wing RC aircraft are used for FPV flight. The most commonly chosen airframes for FPV planes are models with sufficient payload space for a larger battery and large wings for excellent gliding ability. Suitable brushless motors are installed as the most common pushers to provide better flight performance and longer flight time. Pusher-propeller planes are preferred so that the propeller is not in view of the camera. Flying wing designs are also popular for FPV, as they provide a good combination of large wing surface area, speed, maneuverability, and gliding ability.
In the United States, the Academy of Model Aeronautics' (AMA) Safety Code (which governs flying at AMA affiliated fields) allows FPV flight under the parameters of AMA Document #550, which requires that FPV aircraft be kept within visual line of sight with a spotter maintaining unaided visual contact with the model at all times. Similarly, in the United Kingdom, the Civil Aviation Authority (CAA) Air Navigation Order 2009 under General Exemption E 4185 requires small unmanned aircraft (SUA) be kept within visual line of sight with a competent observer maintaining direct unaided visual contact with the model at all times for the purpose of collision avoidance. Because these restrictions prohibit flying beyond the visual range of the pilot (an ability which many view as the most attractive aspect of FPV), most hobbyists that fly FPV do so outside of regular RC clubs and flying fields.
== Types of kits and construction ==
There are various ways to construct and assemble an RC aeroplane. Various kits are available, requiring different amounts of assembly, different costs and varying levels of skill and experience.
Some kits can be mostly foam or plastic, or may be all balsa and ply wood. Construction of wood kits typically consists of using formers and longerons for the fuselage and spars and ribs for the wing and tail surfaces. Many designs use solid sheets of balsa wood instead of longerons to form the fuselage sides and may also use expanded polystyrene for the wing core covered in a wood veneer, often balsa or obeche. Such designs tend to be slightly heavier but are typically easier to build. The lightest models are suitable for indoor flight, in a windless environment. Some of these are made by bringing frames of balsa wood and carbon fiber up through water to pick up thin plastic films, similar to rainbow colored oil films. The advent of "foamies," or craft injection-molded from lightweight foam and sometimes reinforced with carbon fiber, have made indoor flight more readily accessible to hobbyists. EPP (Expanded Polypropylene) foam planes are actually even bendable and usually sustain very little or no damage in the event of an accident, even after a nose dive. Some companies have developed similar material with different names, such as AeroCell or Elapor.
Amateur hobbyists have more recently developed a range of new model designs utilizing corrugated plastic, also sold as Coroplast. These models are collectively called "SPADs" which stands for Simple Plastic Airplane Design. Fans of the SPAD concept tout increased durability, ease of building, and lower priced materials as opposed to balsa models, sometimes (though not always) at the expense of greater weight and crude appearance.
Flying models have to be designed according to the same principles as full-sized aircraft, and therefore their construction can be very different from most static models. RC planes often borrow construction techniques from vintage full-sized aircraft (although they rarely use metal structures).
=== Ready-to-Fly (RTF) ===
Ready to fly (RTF) airplanes come pre-assembled and usually only require wing attachment or other basic assembly. Typically, everything that is needed is provided, including the transmitter, receiver and battery. RTF airplanes can be up in the air in just a few minutes and have all but eliminated assembly time (at the expense of the model's configuration options.)
=== Almost Ready-to-Fly (ARF) ===
Almost ready to fly (ARF or ARTF) airplanes require final assembly typically including engine and fuel tank installation (or electric motor, speed controller, and battery), servo and pushrod installation, control surface attachment, landing gear attachment, and sometimes require gluing the left and right wing halves together. The average ARF airplane can be built with less than 10 to 20 hours of labor, versus 50 to 100+ hours (depending on detail and desired results) for a typical wood kit. The fuselage, wing halves, tail surfaces and control surfaces are already constructed. ARF airplanes typically only include the airframe and some accessories such as pushrods, fuel tank, etc. Therefore, the power system (glow engine, gas engine, or electric motor and any required accessories) and radio system (servos, transmitter, receiver, and battery) must be purchased separately.
Hobby Companies like Motion RC and Horizon Hobby have also began to sell ARF+ Models or ARF Plus which are models that are between a full ARF and PNP where they will have some electronics like control surface servos and retracts for the landing gear but will not include a power system (ESC and Motor)
=== Bind-N-Fly (BNF) ===
Bind-N-Fly (BNF) aircraft are similar to Ready to fly aircraft, except they do not come with a transmitter. Because they do not come with a transmitter, they must be bound to one instead. This is desirable for flyers that already own a transmitter. Like RTF aircraft, Bind-N-Fly models require minimal assembly.
There are several incompatible radio standards often found with Bind-N-Fly models. Most commonly seen are the BNF and Tx-R designations. BNF models work with transmitters using the DSM2/DSMX standard, and Tx-R models use the Tactic/AnyLink standard. A programmable transmitter which can store custom parameters for multiple models is desirable so that trim and other advanced functions do not need to be altered when switching models.
Receiver Ready (Rx-R) models are similar to BNF models in that they are mostly assembled but let the user add their own receiver and battery, avoiding the need to deal with transmitter incompatibilities.
=== Plug-N-Play (PNP) ===
A Plug-N-Play (PNP) electric RC airplane has the motor, ESC and servos installed but is missing the transmitter, receiver, and motor battery pack (& charger). In other words, the airplane comes 99% assembled just like an RTF one does, but you need to supply your own transmitter, receiver, and battery pack. Plug-N-Play radio control planes are the perfect answer for aeromodellers who want to buy and fly more than one RTF RC plane, but don't want to have a separate transmitter for each one.
=== Wood Kit ===
Wood kits come in many sizes and skill levels. The wood, typically balsa and light ply, may either be cut with a die-cut or laser. Laser cut kits have a much more precise construction and much tighter tolerances, but tend to cost more than die-cut kits.
Wood kits include the raw material needed to assemble the airframe, a construction manual, and full-size plans. Assembling a model from plans or a kit can be very labor-intensive. In order to complete the construction of a model, the builder typically spends many hours assembling the airframe, installing the engine and radio equipment, covering it, sometimes painting it, installing the control surfaces and pushrods, and adjusting the control surfaces travels. The kit does not include necessary tools, so they must be purchased separately. Care must be taken when building models from wood kits since construction flaws may affect the model's flying characteristics or even result in structural failure.
Smaller balsa kits will often come complete with the necessary parts for the primary purpose of non-flying modeling or rubber band flight. These kits will usually also come with conversion instructions to fly as glow (gas powered) or electric and can be flown free-flight or radio-controlled. Converting a kit requires additional and substitution parts to get it to fly properly such as the addition of servos, hinges, speed controls, control rods and better landing gear mechanisms and wheels.
Many small kits will come with a tissue paper covering that then gets covered with multiple layers of plane dope which coats and strengthens the fuselage and wings in a plastic-like covering. It has become more common to cover planes with heat-shrinking plastic films backed with heat-sensitive adhesive. These films are generally known as 'iron-on covering' since a hand-held iron allows the film to be attached to the frame; a higher temperature then causes the film to tighten. This plastic covering is more durable and makes for a quick repair. Other varieties of heat shrinkable coverings are also available, that have fibrous reinforcements within the plastic film, or are actual woven heat shrinkable fabrics.
It is common to leave landing gear off smaller planes (roughly 36" or smaller) in order to save on weight, drag and construction costs. The planes can then be launched by hand-launching, as with smaller free-flight models, and can then land in soft grass. Flute board or Coroplast can be used in place of balsa wood.
=== From plans or scratch ===
Planes can be built from published plans, often supplied as full-sized drawings with included instructions. Parts normally need to be cut out from sheet wood or foam using supplied templates. Once all of the parts have been made, the project builds up just like a wood kit. A model plane built from scratch ends up with more value because you created the project from the plans. There is more choice of plans and materials than with kits, and the latest and more specialized designs are usually not available in kit form. The plans can be scaled to any desired size with a computer or copy machine, usually with little or no loss in aerodynamic efficiency.
Hobbyists that have gained some experience in constructing and flying from kits and plans will often venture into building custom planes from scratch. This involves finding drawings of full-sized aircraft and scaling these down, or even designing the entire airframe from scratch. It requires a solid knowledge of aerodynamics and a plane's control surfaces. Plans can be drawn up on paper or using CAD software.
== Airframe materials ==
Several materials are commonly used for construction of the airframe of model radio-controlled aircraft.
The earliest model radio-controlled aircraft were constructed of wood covered with paper. Later, plastic film such as Monokote came to be widely used as a covering material. Wood has relatively low cost, high specific Young's modulus (stiffness per unit weight), good workability and strength, and can be assembled with adhesives of various types. Light-weight strong varieties such as balsa wood are preferred; basswood, pine and spruce are also used.
Carbon fiber, in rod or strip form, supplements wood in more recent models to reinforce the structure, and replaces it entirely in some cases (such as high performance turbine engine powered models and helicopters). The disadvantage of using carbon fiber is its high cost.
Expanded polystyrene and extruded polystyrene foam (Styrofoam) came to be used more recently for the construction of the entire airframe. Depron (the type of foam used for meat trays) blends rigidity with flexibility, allowing aircraft to absorb the stress of flying. Expanded polypropylene (EPP) is an extremely resilient variety of foam, often used in basic trainers, which take considerable abuse from beginners. Foam is used either in an injection mold to make a molded airframe or is cut out of sheet to make a built up airframe similar to some wood airframes. Airplanes of foam construction are frequently referred to as "Foamies".
Twinwall extruded polypropylene sheet has been used from the mid nineties. Commonly known as Correx in the United Kingdom, it is mentioned in the sections above. Currently the Mugi group based in West Yorkshire still promote and use this material in 2mm thickness sheet form. Very tough and lightweight it has only two disadvantages. Firstly it needs particular two-part contact glues. Secondly the material is difficult to paint due to low surface adhesion. Self-adhesive coloured tapes were the answer. Components are often laminated, taking advantage of differing flute directions for strength and forming. Models tend to exceed 900mm wingspan with carbon fibre tubing used for local reinforcement. The thickness used among modellers is from 2mm to 4 mm thickness. Models made out of this material are commonly known among modellers as "Spad" types (simple plastic aeroplane design).
PLA and ABS are used as material to print models using 3D printers.
== Plane characteristics ==
=== Number of channels ===
The number of channels (technically, servo channels) a plane has is normally determined by the number of mechanical servos that have been installed, with a few exceptions, such as the aileron servos, where two servos can operate via a single channel using a Y harness (with one of the two servos rotating in the opposite direction). On smaller models, usually one servo per control surface (or set of surfaces in the case of ailerons or a split elevator surface) is sufficient. Generally, for a plane to be considered fully functional, it must have four channels (elevator, rudder, throttle, and ailerons).
==== Basic flight controls ====
A four-channel RC system gives the aeromodeler the same basic degree of control that a full-sized aircraft's primary flight controls do:
Elevator (or horizontal stabilizer) – controls pitch (up and down).
Rudder (or vertical stabilizer) – controls yaw (left and right).
Throttle – controls engine rpm (or thrust for jets and ducted fans, or motor speed for electric RC Aircraft).
Ailerons – control roll.
==== Extra flight control functionality ====
Gear/retracts – controls retractable landing gear (usually in conjunction with gear doors).
Flaps – Increase lift, but also increase drag. Using flaps, an aircraft can fly slower before stalling. Flaps are often used to steepen the landing approach angle and let the plane land at a slower touchdown speed (as well as letting the aircraft lift off at a slower takeoff speed). In both cases, flaps reduce the wear and tear on the airplane landing gear system, and enable an aircraft to use a shorter runway than would otherwise be required.
Auxiliary control – Additional channels can control additional servos for propeller pitch (such as on 3D planes), or control surfaces such as slats, spoilers, flaps, spoilerons, flaperons, or elevons.
Misc – bomb bay doors, lights, remote camera shutter can be assigned to extra channels. Additionally, if there is a flight assist or autopilot module on the craft (more common on the multi-rotor copters), features such as gyro-based stabilization, GPS location hold, height hold, return home, etc., can be controlled.
Three channels (controlling rudder or (rarely) ailerons, along with the elevator and throttle) are common on trainer aircraft. Four channel aircraft, as mentioned above, have controls for elevator, rudder, throttle, and ailerons.
For complex models and larger scale planes, multiple servos may be used on control surfaces. In such cases, more channels may be required to perform various functions such as deploying retractable landing gear, opening cargo doors, dropping bombs, operating remote cameras, lights, etc. Transmitters are available with as few as 2 channels to as many as 28 channels.
The right and left ailerons move in opposite directions. However, aileron control will often use two channels to enable mixing of other functions on the transmitter. For example, when they both move downward they can be used as flaps (flaperons), or when they both move upward, as spoilers (spoilerons). Delta winged aircraft designs commonly lack a separate elevator, its function being mixed with the ailerons and the combined control surfaces being known as elevons. V-tail mixing, needed for such full-scale aircraft designs as the Beechcraft Bonanza, when modeled as RC scale miniatures, is also done in a similar manner as elevons and flaperons.
Very small ready to fly RC indoor or indoor/outdoor toy aircraft often have two speed controllers and no servos, in order to cut production costs and lower sale price. There can be one motor for propulsion and one for steering or twin motors with the sum controlling the speed and the difference controlling the turn (yaw).
Some .049 glow models use two controls: elevator and rudder with no throttle control. The plane is flown until it runs out of fuel then lands in the fashion of a glider.
=== Turning ===
Turning is generally accomplished by rolling the plane left or right and applying the correct amount of up-elevator ("back pressure"). A three channel RC plane will typically have an elevator and a throttle control, and either an aileron or rudder control but not both.
If the plane has ailerons, rolling the wings left or right is accomplished directly by them. If the plane has a rudder instead, it will be designed with a greater amount of dihedral effect, which is the tendency for the airplane to roll in response to sideslip angle created by the rudder deflection. Dihedral effect in model airplane design is usually increased by increasing the dihedral angle of the wing (V-bend in the wing). The rudder will yaw the plane so that it has a left or right sideslip, dihedral effect will then cause the plane to roll in the same direction. Many trainers, electric park fliers, and gliders use this technique.
A more complex four channel model can have both rudder and ailerons and is usually turned like a full-sized aircraft. That is, the ailerons are used primarily to directly roll the wings, and the rudder is used to "coordinate" (to keep the sideslip angle near-zero during the rolling motion). Sideslip otherwise builds up during an aileron-driven roll because of adverse yaw. Often, the transmitter is programmed to automatically apply rudder in proportion to aileron deflection to coordinate the roll.
When an airplane is in a small to moderate bank (roll angle) a small amount of 'back pressure' is required to maintain height. This is required because the lift vector, which would be pointing vertically upwards in level flight, is now angled inwards so some of the lift is turning the aircraft. A higher overall amount of lift is required so that the vertical component remains sufficient for a level turn.
Many radio-controlled aircraft, especially the toy class models, are designed to be flown with no movable control surfaces at all. Some model planes are designed this way because it is often cheaper and lighter to control the speed of a motor than it is to provide a moving control surface. Instead, "rudder" control (control over sideslip angle) is provided by differing thrust on two motors, one on each wing. Total power is controlled by increasing or decreasing the power on each motor equally. Usually, the planes only have only these two control channels (total throttle and differential throttle) with no elevator control. Turning a model with differential thrust is equivalent to and just as effective as turning a model with rudder. Lack of elevator control is sometimes problematic if the phugoid oscillation isn't well-damped leading to unmanageable "porpoising". See "Toy class RC" section.
=== V-tail systems ===
A V-Tail is a way of combining the control surfaces of the standard "+" configuration of rudder and elevator into a V shape. These ruddervators are controlled with two channels and mechanical or electronic mixing. An important part of the V-Tail configuration is the exact angle of the two surfaces relative to each other and the wing, otherwise the ratio of elevator and rudder outputs will be incorrect.
The mixing works as follows: When receiving rudder input, the two servos work together, moving both control surfaces to the left or right, inducing yaw. On elevator input, the servos work opposite, one surface moves to the "left" and the other to the "right" which gives the effect of both moving up and down, causing pitch changes in the aircraft.
V-Tails are very popular in Europe, especially for gliders. In the US, the T-Tail is more common. V-Tails have the advantage of being lighter and creating less drag. They also are less likely to break at landing or take-off due to the tail striking something on the ground like an ant mound or a rock.
== Powerplants ==
Most planes need a powerplant to drive them, the exception being gliders. The most popular types for radio-controlled aircraft are internal combustion engines, electric motors, jet engines, and rocket engines. Three types of internal combustion engines are available being small 2 and 4 stroke engines. Glowplug engines use methanol and oil as fuel, compressive ignition ('diesel') burn paraffin with ether as an ignition agent. Larger engines can be glowplug but increasingly common gasoline is the fuel of choice. These engines are spark ignited.
In recent years electric powered models have increased in popularity due to the reducing cost and weight of components and improvements in technology, especially lithium polymer (LiPo) batteries and the choice of brushed motors and brushless motors. Electric systems are quieter and as they do not require fuel/exhaust, are cleaner. The advantage of electric power is the ease of starting the motor as compared to the starting of engines; electric motors that are comparable to engines are cheaper. Any form of lithium-chemistry battery cell technology packs have to be charged with "smart" chargers that have connections to every electrical connection in the pack to "balance-charge" the cells in the pack, and even with proper use of such chargers lithium-polymer battery packs can have the serious risk of fire or explosion, which has led to the increasing acceptance of cobalt-free, lithium iron phosphate battery technology in their place as a much more rugged and durable lithium-chemistry power source.
== Transmitting and Receiving Frequencies ==
=== Frequency ===
A transmitter and receiver of a radio control aircraft must both be on the same frequency so the aircraft can be controlled in flight. Traditionally, this transmitting and receiving frequency were referred to as a channel (technically, a frequency channel). This is not the same as number of servo channels that a plane can have, and can be confusing, as both are casually referred to as channels. It is less common now for radio control pilots to refer to frequency channels, as modern computer receivers in the gigahertz bands are equipped with synthesiser technology and are 'locked' to the computer transmitter being used.
==== Reserved frequencies ====
Many countries reserve specific frequency bands (ranges) for radio-control use. Due to the longer range and potentially worse consequences of radio interference, model aircraft have exclusive use of their own frequency allocation in some countries.
===== USA and Canada reserved VHF frequency bands =====
72 MHz: aircraft only (France also uses US/Canada channels 21 through 35).
75 MHz: surface vehicles.
53 MHz: all vehicles, only for older equipment on 100 kHz spacing, with the operator holding a valid amateur radio (FCC in the USA) license. The 53 MHz band began to become vulnerable to amateur radio repeater stations operating on the 53 MHz area of the 6-meter band during the early 1980s. The 53 MHz bands can still be used with relative safety for ground-based (cars, boats/ships) powered modeling activities.
50.8 to 51 MHz: on the 6-meter band for all vehicles at 20 kHz spacing, with the operator holding a valid amateur radio (FCC in the USA) license. Added in the 1980s as the amateur radio repeater interference problem on the earlier 53 MHz bands in the United States began to manifest itself.
27 MHz: first band opened for RC use in the United States and shared with CB radio users: as with 53 MHz for Hams, nowadays preferable for use on ground-based RC models only — also used for older RC toys before 1991.
===== USA and Canada reserved UHF frequency bands =====
2.400-2.485 GHz: 13-cm UHF Spread Spectrum band for general use (amateur radio license holders have 2.39-2.45 GHz licensed for their general use in the USA) and using both frequency-hopping spread spectrum and direct-sequence spread spectrum RF technology to maximize the number of available frequencies on this band, especially at organized events in North America.
US frequency chart available at [1],
Canadian frequency chart available at [2]
===== European reserved VHF & UHF frequency bands =====
35 MHz: aircraft only.
40 MHz: surface vehicles or aircraft.
27 MHz: general use, toys, citizens band radio.
2.4 GHz 13-cm UHF band spread spectrum: surface vehicles, boats and aircraft.
Within the 35 MHz range, there are designated A and B bands. Some European countries allow use only in the A band, whereas others allow use in both bands.
===== United Kingdom reserved frequency bands =====
458.5–459.5 MHz: low-UHF band for surface vehicles or aircraft. (Non-Ham-frequencies – 70-cm amateur band in the UK covers 430-440 MHz)
===== Singapore reserved frequency bands =====
72 MHz: aircraft only
2.4 GHz: 13-cm UHF band aircraft only
===== China reserved frequency bands =====
1.4 GHz: general use
2.4 GHz: 13-cm UHF band general use
5.8 GHz: general use
433 MHz: for amateur radio licensees only
===== Australian reserved frequency bands =====
36 MHz: aircraft and water-craft (odd channels for aircraft only)
29 MHz: general use
27 MHz: light electric aircraft, general use
2.400-2.485 GHz: 13-cm UHF band Spread Spectrum band for general use (ACMA references available at [3])
===== New Zealand reserved frequency bands =====
35 MHz: aircraft only
40 MHz: aircraft only
27 MHz: general use
29 MHz: general use
36 MHz: general use
72 MHz: general use (US 72 MHz "even-numbered" channels 12 through 56, at 40 kHz spacing)
2.400-2.4835 GHz: 13-cm UHF band
The frequencies are permitted under legislation, provided equipment meets the appropriate standards, bears the New Zealand supplier's Supplier Code Number and has the correct compliance documentation.
Detailed information, including cautions for transmitting on some of the 'general use' frequencies, can be found on the NZMAA website.
===== Amateur radio license reserved frequency bands =====
50 and 53 MHz in the US and Canada (American amateurs allowed up to one watt [30 dBm] of output power)
433–434 MHz Formerly used low-UHF band in Germany until the end of 2008, but is still permitted in Switzerland; and is also usable within both the US and Canada, most often implemented nowadays in North America with spread spectrum RF hardware (as on 2.4 GHz).
=== Channels and frequency control ===
Traditionally (since 1967) most RC aircraft in the United States utilized a 72 MHz frequency band for communication – six of these were actually on the 72 MHz band at 80 kHz separation from each other, with one additional isolated frequency at 75.640 MHz. These remained legal to use until the 1983 FCC reform that introduced "narrowband" RC frequencies – at 40 kHz separation from 1983 to 1991, and finally at 20 kHz separation from 1991 onwards, to the present day with fifty frequencies on 72 MHz solely for flying models. The 75 MHz band became usable only for ground-based RC modeling (cars, boats, etc.) in the same timeframe, with the transition also occurring through to 1991, having 30 frequencies available at the same 20 kHz channel separation. Canadian modelers today flying on VHF-band RC gear use the same 72 and 75 MHz frequencies as American hobbyists do, for the same types of models.
The transmitter radio broadcasts using AM or FM using PPM or PCM. Each aircraft needs a way to determine which transmitter to receive communications from, so a specific channel within the frequency band is used for each aircraft (except for 2.4 GHz band, and amateur radio-only 70 cm systems; which use spread spectrum modulation, described below).
Most radio control systems – traditionally on low-VHF-band frequencies before the 21st century – have traditionally used crystals to set the operating channel in the receiver and transmitter. It is important that each aircraft uses a different channel, otherwise interference could result. For example, if a person is flying an aircraft on channel 35 (used for 72.490 MHz in North America), and someone else turns their radio on the same channel, the aircraft's control will be compromised and the result is almost always a crash. Since multiple RC frequency use began in the RC hobbies in the mid-20th century, so-called "frequency pins" have been used to ensure that only one modeler was using a particular frequency at any one time, for "traditional" style, crystal-controlled RC system use. The common, spring-loaded two-piece wood clothespin – marked in some manner with text and/or color-coding for the designated frequency it references, usually with an added piece of thin plywood or plastic on the clothespin to place the text or color-code upon for greater visibility – is the usual basis for these. Usually, the model club itself will possess some sort of "transmitter impound" facility at their modeling site for secure storage of the modelers' transmitters when not in active use while visiting the facility, and usually provides some sort of fixed "frequency control board" nearby to the impound area. The "frequency control board" at a modeling club's facility is used in one of two ways: either the club provides sets of frequency pins itself, already clipped onto the control board for the modeler to take the appropriate pin for their modeling activity (clipped onto their transmitter's antenna, in a so-called "subtractive" method) while their transmitter is in use away from the impound area, or with the modeler required to provide them for their own transmitter(s), and places them on a club facility's existing frequency board (the "additive" method) whenever they are using their RC transmitter.
A modern computer radio transmitter and receiver can be equipped with synthesizer technology, using a phase-locked loop (PLL), with the advantage of giving the pilot the opportunity to select any of the available channels with no need of changing a crystal. This is very popular in flying clubs where a lot of pilots have to share a limited number of channels. Latest receivers now available use synthesiser technology and are 'locked' to the transmitter being used. Dual-conversion radio receivers have been in existence since the 1980s and commonly in use since that time, which add security for the proper reception of the control signal, and can offer the advantage of a built-in 'failsafe' mode. Using synthesised receivers saves on crystal costs and enables full use of the VHF bandwidth available, for example the 35 MHz band.
Newer Transmitters use spread spectrum technology in the 2.4 GHz, upper-UHF frequency band for communication. Spread spectrum technology allows many pilots to transmit in the same band (2.4 GHz) in proximity to each other with little fear of conflicts. Receivers in this band are virtually immune to most sources of electrical interference. Amateur radio licensees in the United States also have general use of an overlapping band in this same area, which exists from 2.39 to 2.45 GHz, with newer aftermarket transmitter RF module/receiver combinations on the 70 cm band also offering user-programmable, spread-spectrum versatility of varying degrees for Ham RC modelers in both the US and Canada, only as secondary users without "exclusive" use provisions.
== Military usage ==
Radio-controlled aircraft are also used for military purposes, with their primary task being intelligence-gathering reconnaissance. An Unmanned Aerial Vehicle (UAV), also known as a drone, is usually not designed to contain a human pilot. Remotely controlled target drone aircraft were used to train gun crews.
== Regulations on use ==
Various countries have regulations and restrictions on model aircraft operations, even for non-commercial purposes, typically imposed by the national civil aviation authority.
=== United States ===
In the United States, radio-controlled model aircraft and unmanned aircraft generally may be subject to regulation by the following entities:
==== Federal Aviation Administration ====
The legal status of radio-controlled model aircraft under federal aviation law is currently unclear. In March 2014 in the case Huerta v. Pirker, an administrative law judge with the National Transportation Safety Board (NTSB) dismissed an FAA enforcement action against a model aircraft operator under 14 CFR 91.13 (prohibiting careless and reckless operation of an aircraft), ruling that model aircraft are not legally classified as "aircraft" and that they are not subject to any current Federal Aviation Regulations (FARs). This decision was appealed to the full NTSB. In November 2014 the NTSB issued a ruling reversing the administrative law judge's decision and holding that model aircraft are legally considered "aircraft" at least for the purposes of 14 CFR 91.13, and remanded the case to the administrative judge to determine whether Pirker's actions constituted reckless operation. It remains unclear what other provisions of the Federal Aviation Regulations are applicable to model aircraft, but it is likely that every regulation applicable to "aircraft" generally would potentially apply under this standard.
In June 2014 the Federal Aviation Administration (FAA) issued a notice of interpretation regarding the Special Rule for Model Aircraft in Section 336 of the FAA Modernization and Reform Act passed by Congress in February 2012, which exempted model aircraft meeting certain criteria from future FAA rulemaking. In this document, the FAA stated its position that, "Model aircraft that do not meet these statutory requirements are nonetheless unmanned aircraft, and as such, are subject to all existing FAA regulations, as well as future rulemaking action, and the FAA intends to apply its regulations to such unmanned aircraft." The notice of interpretation further stated that even model aircraft that do qualify for the Sec. 336 exemption are legally considered aircraft, and the FAA has authority to pursue enforcement actions against model aircraft operators who do not comply with certain provisions of Part 91 of the Federal Aviation Regulations, including the prohibition against careless and reckless operation of an aircraft in 14 CFR 91.13 and 14 CFR 91.113, which requires that "vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft." Because the FAA has not yet sought to enforce this regulation against unmanned aircraft operators, whether it applies to model aircraft and what actions are necessary for compliance are currently unknown. FAA pilot registration for both camera-bearing "small unmanned aircraft system" (sUAS) multirotor "drones" and recreationally-flown traditional radio-controlled aircraft was reinstated by the FAA as part of the National Defense Authorization Act for Fiscal Year 2018, requiring RC aeromodelers to register with the FAA for a $5.00 fee for a three-year registration period: the modeler is assigned a ten-character alphanumeric personal FAA registration code to be placed on their models' exterior surfaces no later than February 25, 2019 as part of the registration requirements, to be placed on the model on any "exterior-viewable" part of the model that requires nothing to be opened – the modeler's registration code is personal for their use, and any number of model aircraft that they own and operate can bear the same registration code.
==== Federal Communications Commission ====
Licensed amateur radio operators in the United States are expressly allowed to use amateur radio frequencies for telecommand of model aircraft, per FCC Part 97's rule 97.215. However, the Federal Communications Commission prohibits using amateur radio frequencies for commercial activity (generally any form of economic gain or for-profit activity, Part 97's rule 97.113). The FCC has not yet addressed the issue of creating designated command and control frequencies for commercial unmanned aircraft, and many civilian unmanned aircraft continue to use amateur radio frequencies, even when used for commercial purposes. Though it has not so far pursued any enforcement actions related to use of amateur radio frequencies for commercial unmanned aircraft (with the FCC, as early as 1997, commencing the authorization of specific "industrial/business" frequency bands, potentially usable for such needs), the FCC has the authority to levy civil forfeitures and fines into the tens of thousands of dollars for violations of its regulations. There is no similar "displayed registration code" requirement as yet from the FCC, to that of the FAA as mentioned above (the FAA's "pilot registration code" must be on the model already), for FCC-licensed amateur radio operators flying RC aircraft under part 97.215. Since mid-July 2000, FCC Amateur Radio Service licensees have already been assigned a ten-digit "FCC registration number" or "FRN" directly linked to their callsign which could additionally be placed on their models along with any already-assigned FAA registration code, if desired. The July 2000 announcement of the "FRN" code system was partly worded: ..."The use of the registration number is voluntary, although the Commission will consider making it mandatory in the future.", leaving its use open for any future FCC-administered Amateur Radio Service needs in the United States.
==== National Park Service ====
Under a 2014 edict from the National Park Service, model aircraft and other unmanned aircraft operations are prohibited on all land administered by the National Park Service, with some exceptions for preexisting model aircraft fields that were established prior to the adoption of this rule. Because the National Park Service does not have jurisdiction over airspace, which is exclusively governed by the FAA, this rule only applies to unmanned aircraft flown from National Park Service land. It does not apply to overflight of National Park Service land by unmanned aircraft operated elsewhere.
==== State and Local Governments ====
There are a wide variety of state and local laws and ordinances affecting model aircraft. Many state and local governments restrict or prohibit model aircraft from being flown at local parks. Some state laws purport to restrict or prohibit aerial photography using unmanned aircraft, though such laws would likely be found invalid if challenged in court due to federal preemption, as the FAA has exclusive regulatory jurisdiction over all aircraft and airspace from the surface up. Any laws restricting aerial photography of areas where no reasonable expectation of privacy exists would also likely be vulnerable to challenges under the First Amendment to the United States Constitution.
==== Academy of Model Aeronautics ====
The Academy of Model Aeronautics' (AMA) Safety Code governs model aircraft operations at all model aircraft clubs and flying fields affiliated with the organization, which includes the majority of designated model aircraft flying fields in the United States.
=== Australia ===
In Australia the operation of model aircraft is subject to laws and regulations regarding radio spectrum use which is enforced by the ACMA (Australian Communications and Media Authority) and the use of airspace as enforced by CASA (Civil Aviation Safety Authority).
All unmanned aeronautical activities in Australia are ruled by CASR (Civil Aviation Safety Regulations) Part 101 which includes sections for UAV's and model aircraft among other operations. It is currently under review and new regulations specifically relating to UAV's and model aircraft are anticipated.
Any commercial use (i.e. any form of payment or benefit) of an unmanned aircraft results in the operations falling under the Unmanned Aerial Vehicle (UAV) Operations Section, CASR 101-1. This section requires formal licensing, training and documentation procedures to be approved and followed. These requirements will typically require an outlay in the order of thousands of dollars which places commercial operations beyond the reach of most hobbyists. This is one area currently under review by CASA with initial reports indicating a potential option of simpler registration for light-weight UAV's without requiring formal certification.
Non-commercial use is governed by section 101-3 which includes requirements that:
No commercial benefit is to be obtained from operating the model – to be flown only for sport or recreational purposes
Maximum weight of 150 kg (models over 25 kg must be operated within a club setting under additional conditions)
Models under 100 grams are exempt from regulation
Only to be flown in daylight unless under written procedures of an authorised organisation (such as the MAAA)
The model must remain within continuous direct sight of the operator
When within 3 nautical miles of an aerodrome or when within controlled airspace, flight is limited to 400 ft above ground level
=== India ===
There are certain conditions for using the frequency band in which the aircraft will operate. The operator is required to be eligible for that grade. The only requirement in that is the operator's name will be scripted. For self built aircraft a license is required.
== See also ==
3D Aerobatics
Academy of Model Aeronautics
British Model Flying Association
Bruce Simpson who used RC flight control systems in the construction of a homemade cruise missile
Discus Launch Glider
Hotliner
International Miniature Aerobatic Club
List of radio-controlled model aircraft kit manufacturers
Model Aeronautics Association of Canada
Radio-controlled model
RC flight simulator
== References ==
== External links ==
FAI Competition Class F Radio Control Frequency Listing
Dedicated Wiki For Electric RC Flight
Official FAA "DroneZone" Pilot Registration Page for United States Aeromodelers | Wikipedia/Radio-controlled_aircraft |
Rail transport modelling uses a variety of scales (ratio between the real world and the model) to ensure scale models look correct when placed next to each other. Model railway scales are standardized worldwide by many organizations and hobbyist groups. Some of the scales are recognized globally, while others are less widespread and, in many cases, virtually unknown outside their circle of origin. Scales may be expressed as a numeric ratio (e.g. 1/87 or 1:87) or as letters defined in rail transport modelling standards (e.g. HO, OO, N, O, G, TT and Z.) The majority of commercial model railway equipment manufacturers base their offerings on Normen Europäischer Modellbahnen (NEM) or National Model Railroad Association (NMRA) standards in most popular scales.
== Terminology ==
Although scale and gauge are often confused, scale means the ratio between a unit of measurement on a model compared with a unit of measurement in corresponding full size prototype, while gauge is the distance between the two running rails of the track. About 60% of the world's railways have a track gauge of 4 ft 8+1⁄2 in (1,435 mm) known as "standard gauge", but there are also narrow-gauge railways where the track gauge is less than standard and broad-gauge railways where the gauge is wider. In a similar manner, a scale model railway may have several track gauges in one scale.
In addition to the scale and gauge issue, rail transport modelling standards are also applied to other attributes such as catenary, rolling stock wheel profile, loading gauge, curve radii and grades for slopes, to ensure interoperation of scale models produced by different manufacturers. Globally, the two dominating standard organizations are NMRA in North America and MOROP in Europe with their NEM standard.
== History of scale standards ==
The first model railways were not built to any particular scale and were more like toys than miniature representations. Eventually, models became more accurate, and benefits of standardization became more obvious. The most significant and the most basic area of standardization was the model track gauge. At first, certain gauges became de facto standards for hobbyists and manufacturers. While the first unofficial standard gauges made interchangeability possible, the models were still only a rough approximation of rolling stock.
Eventually unofficial or manufacturer-specific scale standards became more established, and model railway standardisation bodies such as the NMRA and MOROP formalised them. However, they were very often poorly implemented in design and manufacturing processes with commercial manufacturers before the World War II. The conformity to scale standards grew strongly in the 1950s and 1960s when many new model railway accessories manufacturers were born and to whom the standard conformity was vital.
=== Inaccuracy to improve reliability ===
For most standardized model railway scales, the nominal scale reduction ratio is not applied systematically to all the components of a scale model railway, and normally the standards give scale specific design guidelines for all the scales they cover. Reliability of operations requires that certain parts be made oversize. A typical example is the wheel flanges, which must be proportionally higher in smaller scales to ensure that lighter and smaller models do not derail easily as they would if universal flange proportions were used in all the scales. For instance, a Z scale wheel flange as defined in the NEM standard should be about 9% of the scale nominal standard gauge (6.5 mm / 0.256 in), whereas the same standard gives only 5% for 45 mm (1.772 in) standard-gauge I scale.
=== Finescale standards ===
Modellers who were dissatisfied with inaccuracies in the name of reliability have developed alternative finescale standards. Finescale standards are very much restricted to discerning hobbyists since, by definition, finescale model railways are generally less reliable and more expensive to manufacture, which makes them unsuitable for mass-production products.
=== Linear propulsion ===
One limitation with smaller scales is that the small size of the metal contacts means it is easier for dust and dirty track to interfere with the electrical circuit needed to drive the train. Moreover, the tight tolerances also mean friction can more easily interfere with the train moving. One approach to enable further miniaturization beyond T Scale is the recent commercial introduction of linear drive motors. The magnetic propulsion eliminates moving parts, simplifying motion and models. Commercially available scales using linear propulsion drive range from 1:655 to 1:1000.
== Scale standards ==
Most standards are regional, but some have followers in other parts of the world outside their native region, most notably NEM and NMRA. While the most significant standardised dimension of a model railway scale is the gauge, a typical scale standard covers many more aspects of model railways and defines scale-specific dimensions for items like catenary, rolling stock wheels, loading gauge, curve radii and grades for slopes, for instance.
=== NEM ===
MOROP (the European federation of national model railway associations) is a European organisation which publishes NEM-standards. NEM-standards are used by model railway industry and hobbyists in Europe. The standards are published in French and German and both versions have an official status. Unofficial translations in English from third parties exist for certain NEM-standard sheets.
Model railway scales and gauges are standardized in NEM 010, which covers several gauges for each scale. Narrow gauges are indicated by an additional letter added after the base scale as follows:
no letter = standard gauge (1,250–1,700 mm or 49.2–66.9 in)
m = metre gauge (850–1,250 mm or 33.5–49.2 in)
e = narrow gauge (650–850 mm or 25.6–33.5 in)
i = industrial (400–650 mm or 15.7–25.6 in)
p = park railway (300–400 mm or 11.8–15.7 in)
For instance, a metre-gauge model railway in H0-scale is designated H0m. In German text the letter "f" (for Feldbahn) is sometimes used instead of "i". The letter "e" represents the French word for "narrow", étroit. NEM gauges are arranged conveniently to use the normal gauge of smaller scales as narrow gauges for a certain scale. For instance, H0m gauge is the same as the TT-scale normal gauge, H0e same as the N-scale normal gauge and H0i same as the Z-scale normal gauge.
For H0 and 0 scales, NEM uses the number zero, and NMRA uses letter "O" (HO instead of H0).
=== NMRA ===
The NMRA (National Model Railroad Association) standardized the first model railway scales in the 1940s. NMRA standards are used widely in North America and by certain special interest groups all over the world. To some extent NMRA and NEM standards are compatible, but in many areas, the two standards specify certain model railway details in somewhat incompatible ways for the same scale.
There are two NMRA standard sheets where the scales have been defined. NMRA standard S-1.2 covers the popular model railway scales and S-1.3 defines scales with deep flanges for model railways with very sharp curves or other garden railway specific design features.
In certain NMRA scales an alternative designation is sometimes used corresponding the length of one prototype foot in scale either in millimetres or in inches. For instance, 3.5 mm scale is the same as HO. For HO and O -scales, NMRA uses the letter "O" whereas NEM uses the number zero (H0 instead of HO).
The NMRA published alternative, more accurate and realistic standards for track and wheels sheet in S-1.1 These model railway standards are based on the full size prototype standards and the scale model operational reliability is therefore reduced in comparison to the models conforming to the normal NMRA standards. Proto and finescale rails and wheels are generally not compatible with the normal scale model railway material with the same scale ratio.
Proto scale was originally developed by the Model Railway Study Group in Great Britain in 1966 and later adopted into NMRA standards with modifications necessary for the North American prototype railway standards. Proto scale reproduces faithfully the prototype wheel tread profile and track work used by the Association of American Railroads and the American Railway Engineering Association.
Finescale reproduces the prototype wheel tread profile and track work used by the Association of American Railroads and the American Railway Engineering Association with minor compromises for performance and manufacturability.
==== NMRA popular railway scales ====
Note: to interpret the number in the left-hand column, these examples illustrate:
3.5 mm scale (HO): 3.5 mm scale measurement = 1 foot (304.8 mm) prototype. The ratio is therefore 1:87.08571, usually reported as 1:87.
1 in scale: 1 in scale measurement = 1 foot prototype, the ratio is reported as 1:12.
==== NMRA deep flange scales ====
==== NMRA proto scales ====
==== NMRA finescale ====
=== British ===
The main railways in Great Britain use the international standard gauge of 4 ft 8+1⁄2 in (1,435 mm) but the loading gauge is narrower and lower than in the rest of Europe with the same standard gauge. This is one of the main reasons why the country has traditionally used its own distinctive model railway scales which can rarely be found outside the British Isles.
When H0 scale was being introduced, the motors available were too large to fit in scale-sized bodies and so as a compromise the scale was increased from 3.5 mm to 4 mm to the foot, but the gauge was not changed so other elements could be shared. For 00 therefore the track is about 12.5% narrower than it should be for the scale used. EM and P4 standards correct this anomaly by adopting a wider track gauge.
The globally more-widespread international NEM and NMRA scale standards are relatively rare in Great Britain and used almost exclusively by those modelling foreign prototypes.
=== Japanese ===
While there are Japanese model railway manufacturers that export their products to other parts of the world and follow the scale standards of the export destinations, in Japan there are several domestic scales that are popular in the country but virtually unknown elsewhere. International NEM and NMRA scales are also used by some Japanese modellers. The main reason for the domestic scales different from international standards is the smaller prototype loading gauge and unusual gauges of Japanese railways: 600 mm (1 ft 11+5⁄8 in), 762 mm (2 ft 6 in) and 1,067 mm (3 ft 6 in) are used, along with standard gauge of 1,435 mm (4 ft 8+1⁄2 in).
=== Lego trains ===
Lego trains use a fixed nominal gauge of 37.5 mm (1+15⁄32 in), based on 5-stud track centerlines gauge.
The 37.5 mm length is not derived by a certain scale ratio. While HO scale is a 1:87 scale (3.5 mm to 1 foot), resulting in a 16.5 mm (0.65 in) gauge from real life prototype 1,435 mm (4 ft 8+1⁄2 in) standard gauge standard gauge.
Conversely, modeling standard gauge in Lego trains would yield a scaling of (37.5:1435 =) 1:38.3.
=== Live steam ===
Live steam model railways are not standardized systematically by any single standardization body. There are, however, certain scales and gauges which have become de facto standards and in some cases correspond to either NEM or NMRA standard scales. One example is the "IBLS" (International Brotherhood of Live Steamers), an informal organization which has published standards for some of the gauges. Many clubs have their own standards, which also may vary slightly from country to country. Hornby Railways have pioneered commercial model live steam in 00 (1:76 scale on 16.5 mm gauge), the existing models are heated using a controllable electric current through the two running rails and have the steam pressure chamber in the model tender.
In addition to these scales, the United Kingdom has, over the last forty years, fathered a scale that is based on the predominant British narrow track gauge of 2 ft (610 mm). Using 32 mm (1.26 in) - 0 gauge - track, there is an extensive range of 16 mm to the foot scale [1:19] live-steam and other types of locomotives, rolling stock and accessories. Many of these models are dual gauge, and can be converted to run on 45 mm (1.772 in) track (gauge 1), and radio control is common. Locomotives in this scale are generally large and "chunky", and can range from the tiny 0-4-0 seen on Welsh slate quarry lines all the way up to the very largest found in the UK, such as the ex-ACR NG/G16 Beyer-Garratt locomotives, seen running on the Welsh Highland Railway in North Wales. The hobby is supported by a number of 16 mm live steam and electric traction builders, dominated by the likes of Roundhouse Engineering and Accucraft UK.
=== Static model ===
=== Historical ===
There have been many short-lived and often promising model railway scales which are very much defunct nowadays. Quite often these were backed by only the company that created a new scale in the first place.
== Mixing of scales ==
It is possible to use different scales of models together effectively, especially to create a false sense of depth (referred to as "forced perspective"). Scales close to each other are also hard to tell apart with the naked eye. An onlooker seeing a 1:43 model car next to a 1:48 scale model train would probably not notice the difference.
Some common examples of mixing scales are:
a foreshortening technique using N scale (1:160) model trains in the background (distance) with HO scale (1:87) in the foreground.
mixing 1:43 scale, 1:48 scale and 1:50 scale die-cast models with O scale model trains.
using Matchbox cars (1:64 to 1:100) with HO scale and S scale.
mixing OO scale British model trains with HO scale models. Both scales run on the same track but OO is slightly larger in scale.
using 1:144 scale die-cast models with N scale.
== List of scales ==
== See also ==
Rail transport modelling
List of scale model sizes
The Museum of the Moscow Railway
National Model Railroad Association
Normen Europäischer Modelleisenbahnen
Rail transport modelling
List of narrow gauge model railway scales
== References ==
== External links ==
http://www.spikesys.com/Modelrr/scales.html – Contains more specifics about some of the scales
https://dfarq.homeip.net/sizes-of-model-trains/ – Contains photos of human hand comparison to each scale
http://modeltrains.about.com Archived 2017-01-29 at the Wayback Machine – Online resource for model railroaders
The Gauge One Model Railway Association
The Gauge 3 Society
Mundo Ferroviario Archived 2009-05-01 at the Wayback Machine, Web portal dedicated to a modelling in HO scale (Spanish).
"About Gauge" guide from Lionel discussing O versus O27 gauge
"More About Gauge" guide from Lionel discussing gauges other than O | Wikipedia/Rail_transport_modelling_scale_standards |
A plastic model kit, (plamo in Eastern influenced parlance), is a consumer-grade plastic scale model manufactured as a kit, primarily assembled by hobbyists, and intended primarily for display. A plastic model kit depicts various subjects, ranging from real life military and civilian vehicles to characters and machinery from original kit lines and pop fiction, especially from eastern pop culture. A kit varies in difficulty, ranging from a "snap-together" model that assembles straight from the box, to a kit that requires special tools, paints, and plastic cements.
== Subjects ==
The most popular subjects of plastic models by far are vehicles such as aircraft, ships, automobiles, and armored vehicles such as tanks. The majority of models throughout its early history depict military vehicles, due to the wider variety of form and historical context compared to civilian vehicles. Other subjects include science fiction vehicles and mecha, real spacecraft, buildings, animals, human(oid) dolls/action figures, and characters from pop culture.
While military, ship, and aircraft modelers prize accuracy above all, modelers of automobiles and science-fiction themes may attempt to duplicate an existing subject, or may depict a completely imaginary subject. The creation of custom automobile models is related to the creation of actual custom cars and often an individual may have an interest in both, although the cost of customizing a real car is obviously enormously greater than that of customizing a model.
== Construction and techniques ==
The first plastic models were injection molded in cellulose acetate (e.g. Frog Penguin and Varney Trains), but currently most plastic models are injection-molded in polystyrene, and the parts are bonded together, usually with a plastic solvent-based adhesive, although modelers may also use epoxy, cyanoacrylate, and white glue where their particular properties would be advantageous. While often omitted by novice modellers, specially formulated paint is sold for application to plastic models. Complex markings such as aircraft insignia or automobile body decorative details and model identification badges are typically provided with kits as screen-printed water-slide decals.
Recently, models requiring less skill, time, and/or effort have been marketed, targeted to younger or less skilled modelers as well as those who just wish to reduce the time and effort required to complete a model. One such trend has been to offer a fully detailed kit requiring normal assembly and gluing, but eliminate the often frustrating task of painting the kit by molding it out of colored plastic, or by supplying it pre-painted and with decals applied. Often these kits are identical to another kit supplied in normal white or gray plastic except for the colored plastic or the prepainting, thus eliminating the large expense of creating another set of molds.
Another trend which has become very extensive is to produce kits where the parts snap together, with no glue needed; sometimes the majority of the parts snap together with a few requiring glue. Often there is some simplification of detail as well; for instance, automotive kits without opening hoods and no engine detail, or sometimes opaque windows with no interior detail. These are often supplied in colored plastic, although smaller details would still require painting. Decals are usually not supplied with these but sometimes vinyl stickers are provided for insignia and similar details.
Resin casting and vacuum forming are also used to produce models, or particular parts where the scale of production is not such as to support the investment required for injection molding.
Plastic ship model kits typically provide thread in several sizes and colors for the rigging. Automobile kits typically contain vinyl tires, although sometimes these are molded from polystyrene as well, particularly in very inexpensive kits. Thin metal details produced by photoetching have become popular relatively recently, both as detailing parts manufactured and sold by small businesses, and as parts of a complete kit. Detail parts of other materials are sometimes included in kits or sold separately, such as metal tubing to simulate exhaust systems, or vinyl tubing to simulate hoses or wiring.
== Scales ==
Almost all plastic models are designed in a well-established scale. Each type of subject has one or more common scales, though they differ from one to the other. The general aim is to allow the finished model to be of a reasonable size, while maintaining consistency across models for collections. The following are the most common scales for popular subjects:
Aircraft: 1/24, 1/32, 1/48, 1/72, 1/100, and 1/144. The most popular scales are 1/48 and 1/72.
Military vehicles: 1/16, 1/24, 1/32, 1/35, 1/48, 1/72, and 1/76.
Automobiles: 1/8, 1/12, 1/16, 1/18, 1/20, 1/24, 1/25, 1/32, 1/35, and 1/43.
Ships: 1/72, 1/96, 1/144, 1/200, 1/350, 1/400 1/450, 1/600, and 1/700.
Figures: 1/72, 1/48, 1/35, 1/24, 1/16, 1/13, 1/8, 1/6, and 1/4. The smaller scale figures are usually used in dioramas; the larger scales (1/8 and 1/6) are popular for stand-alone subjects.
Figurine busts: 1/12, 1/10, 1/9
Railways: 1:43.5 (7 mm/1 ft : O scale), 1:76.2 (4 mm/1 ft : OO scale), 1:87 (3.5 mm/1 ft : HO scale)
Mecha: 1/144, 1/100, 1/72, 1/60, and 1/35.
In reality, models do not always conform to their nominal scale; there are 1/25 scale automobile models which are larger than some 1/24 scale models, for instance. For example, the engine in the recent reissue of the AMT Ala Kart show truck is significantly smaller than the engine in the original issue. AMT employees from the 1960s note that, at that time, all AMT kits were packaged into boxes of a standardized size, to simplify shipping; and the overriding requirement of designing any kit was that it had to fit into that precise size of box, no matter how large or small the original vehicle. This practice was common for other genres and manufacturers of models as well. In modern times this practice has become known as fit-the-box scale. In practice, this means that kits of the same subject in nominally identical scales may produce finished models which actually differ in size, and that hypothetically identical parts in such kits may not be easily swapped between them, even when the kits are both by the same manufacturer.
The shape of the model may not entirely conform to the subject, as well; reviews of kits in modeling magazines often comment on how well the model depicts the original.
== History ==
The first plastic models were manufactured at the end of 1936 by Frog in the UK, with a range of 1/72nd scale model kits called 'Penguin'. In the late 1940s several American companies such as Hawk, Varney, Empire, Renwal and Lindberg began to produce plastic models. Many manufacturers began production in the 1950s and gained ascendancy in the 1960s such as Aurora, Revell, AMT, and Monogram in America, Airfix in UK and Heller SA in France. Other manufacturers included; Matchbox (UK), Italeri, ESCI, (both Italian) Novo {ex-Frog moulds} (former Soviet Union), and Fujimi, Nichimo,Tamiya Corporation and Bandai (Japan).
American model companies who had been producing assembled promotional scale models of new automobiles each year for automobile dealers found a lucrative side business selling the unassembled parts of these "promos" to hobbyists to assemble, thus finding a new revenue stream for the injection molds which were so expensive to update each year. These early models were typically lower in detail than currently standard, with non-opening hoods and no engines, and simplified or no detail on the chassis, which attached to the body with very visible screws. Within a short time, the kit business began to overshadow the production of promos, and the level of accuracy and detail was raised to satisfy the demands of the marketplace.
In the 1960s, Tamiya manufactured aircraft kits in the peculiar (at the time) scale of 1/100. Although the range included famous aircraft such as the Boeing B-52 Stratofortress, McDonnell Douglas F-4 Phantom II, North American F-86 Sabre, Dassault Mirage III, Grumman A-6 Intruder and the LTV A-7 Corsair II, it never enjoyed the same success as 1/72 scale kits did. Soon, Tamiya stopped manufacturing 1/100 scale aircraft but re-issued a small selection of them in 2004.
Since the 1970s, Japanese firms such as Hasegawa and Tamiya, and since the 1990s also Chinese firms such as DML, AFV Club and Trumpeter have dominated the field and represent the highest level of technology. Brands from Russia, Central Europe, and Korea have also become prominent recently with companies like Academy Plastic Model. Many smaller companies have also produced plastic models, both in the past and currently.
Prior to the rise of plastic models, shaped wood models were offered to model builders. These wood model kits often required extensive work to create results easily obtained by the plastic models.
With the development of new technologies, modeling hobby can also be practiced in the virtual world. The Model Builder game, produced by Moonlit studio, available on Steam (service), consists of cutting, assembling, and painting airplanes, helicopters, tanks, cars, and others and making dioramas with them. Transferring the hobby to the game world allows novice modelers and people who do not have space, time, or money to buy multiple models to pursue their interests. Another form of practicing in the virtual world is a 3D modeling with the use of such software like Blender, FreeCAD, Lego Digital Designer (superseded by BrickLink Studio) or LeoCAD, etc.
== Manufacture ==
While injection-molding is the predominant manufacturing process for plastic models, the high costs of equipment and making molds make it unsuitable for lower-yield production. Thus, models of minor and obscure subjects are often manufactured using alternative processes. Vacuum forming is popular for aircraft models, though assembly is more difficult than for injection-molded kits. Early manufacturers of vacuum formed model kits included Airmodel (the former DDR), Contrail, Airframe (Canada), Formaplane, and Rareplanes (UK). Resin-casting, popular with smaller manufacturers, particularly aftermarket firms (but also producers of full kits), yields a greater degree of detail moulded in situ, but as the moulds used don't last as long, the price of such kits is considerably higher. In recent times, the latest releases from major manufacturers offer unprecedented detail that is a match for the finest resin kits, often including high-quality mixed-media (photo-etched brass, turned aluminum) parts.
== Variations ==
Many modellers build dioramas as landscaped scenes built around one or more models. They are most common for military vehicles such as tanks, but airfield scenes and 2-3 ships in formation are also popular.
Conversions use a kit as a starting point, and modify it to be something else. For instance, kits of the USS Constitution ("Old Ironsides") are readily available, but the Constitution was just one of six sister ships, and an ambitious modeller will modify the kit, by sawing, filing, adding pieces, and so forth, to make a model of one of the others.
Scratch building is the creation of a model "from scratch" rather than a manufactured kit. True scratchbuilt models consist of parts made by hand and do not incorporate parts from other kits. These are rare. When parts from other kits are included, the art is technically called "Kit Bashing." Most pieces referred to as "scratchbuilt" are actually a combination of kit bashing and scratchbuilding. Thus, it has become common for either term to be used loosely to refer to these more common hybrid models.
Kitbashing is a modelling technique where parts from multiple model kits are combined to create a novel model form. For example, the effects crews on the various Star Trek TV shows frequently kitbashed multiple starship models to quickly create new classes of ship for use in background scenes where details would not be particularly obvious.
== Issues ==
The demographics of plastic modeling have changed in its half-century of existence, from young boys buying them as toys to older adults building them to assemble large collections. In the United States, as well as some other countries, many modelers are former members of the military who like to recreate the actual equipment they used in service.
Technological advances have made model-building more and more sophisticated, and the proliferation of expensive detailing add-ons have raised the bar for competition within modeling clubs. As a result, a kit built "out of the box" on a weekend cannot compare with a kit built over months where a tiny add-on part such as an aircraft seat can cost more than the entire kit itself.
Though plastic modeling is generally an uncontroversial hobby, it's not immune to social pressures:
In the 1990s, various countries banned Formula One race cars from carrying advertising for tobacco sponsors. In response, manufacturers such as Tamiya removed tobacco logo decals from their race car kits, even those of cars which appeared before the tobacco ban.
The Nazi swastika, which appears on World War 2 Luftwaffe aircraft, is illegal to display in Germany, and disappeared from almost all manufacturers' box illustrations in the 1990s. Some makers still include the emblem on the decal sheet, others have "broken" it into two elements which must be reassembled by the builder, while others have omitted it altogether. Aftermarket decal sheets exist that consist entirely of Luftwaffe swastikas.
A long lasting legal conflict exists between aerospace corporations and the manufacturers of plastic models. Manufacturers of aircraft have sought royalties from model makers for using their designs and intellectual property in their kits. Hobbyists argue that model kits provide free advertising for the makers of the real vehicles and that any royalties collected would be insignificant compared to the profits made from aircraft construction contracts. They also argue that forcing manufacturers to pay royalties and licensing fees would financially ruin all but the largest model kit makers. Some proponents of the aerospace industry contest that the issue is not of financial damages, but of intellectual property and brand image. In contrast, most of the world's commercial airlines allow their fleet to be modeled, as a form of publicity. Many cottage industry manufacturers, particularly of sci-fi subjects, avoid the issue by selling their products under generic untrademarked names (e.g. selling a figure that clearly depicts Batman as "Bat Hero Figure"). Similarly, automobile manufacturers occasionally make an effort to collect royalties from companies modeling their products.
The UK's Ministry of Defence prohibits use of its logos and insignias on commercial products without permission, and according to its licensing policy model and decal manufacturers are required to pay a license fee in order to use Royal Air Force insignia or insignias and logos of any other military unit that was or is a sub-unit of the UK's MOD.
== See also ==
Model aircraft
Ship model
Model military vehicle
Armor Modeling and Preservation Society
International Plastic Modellers' Society (IPMS)
List of scale model kit manufacturers
List of model aircraft manufacturers
Gunpla
Frame Arms Girl
== References ==
Chris Ellis; How to Go Plastic Modelling, Patrick Stephens, 1968 (and subsequent editions).
Gerald Scarborough; Plastic Modelling, Airfix Magazine Guide 1, Patrick Stephens, 1974.
Robert Schleicher (Author) & Harold A. Edmonson (Editor); Building Plastic Models, Kalmbach, 1991.
== External links ==
Media related to Plastic models at Wikimedia Commons
The International Plastic Modellers’ Society, UK (IPMS UK)
The International Plastic Modelers’ Society, USA (IPMS USA)
The International Plastic Modellers’ Society, Canada (IPMS CANADA) | Wikipedia/Plastic_model |
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