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71,764,867 | https://en.wikipedia.org/wiki/Capital%20in%20the%20Anthropocene | Capital in the Anthropocene () is a 2020 non-fiction book by Japanese academic Kohei Saito. Drawing from writings on ecology and natural science by Karl Marx, the book presents a Marxist argument for degrowth as a means of mitigating climate change. Capital in the Anthropocene was an unexpected commercial success in Japan, selling over half a million copies.
Background
Kohei Saito is an associate professor of philosophy at the University of Tokyo. He writes on ecology and political economy from a Marxist perspective, attributing the financial crisis of 2007–2008, the climate crisis, and the Fukushima nuclear disaster as influencing his orientation towards a Marxist interpretation of politics. These events prompted him to consider why "in such an affluent society, there are so many people living in poverty, without access to medical care, and unable to make ends meet," and that despite living in an outwardly convenient and prosperous society, "many people feel that there are no good prospects for the future".
Capital in the Anthropocene draws from Marx's unpublished notebooks on ecological research written late in his life, particularly his writing on natural science and the metabolic rift. In these writings, Marx argues that capitalism has created an "irreparable rift in the interdependent process of social metabolism" and examines self-governing agricultural communes that existed in pre-capitalist societies. From this foundation, Saito mounts an argument for degrowth based on Marx's conclusions.
Synopsis
Saito argues that while sustainable growth has become a central organizing principle in global responses to climate change, the expectation of perpetual growth has only exacerbated the climate crisis. He is particularly critical of the Sustainable Development Goals (SDGs), describing them as "the new opium of the masses" in regards to what he believes is the impossibility for the goals to be achieved under a capitalist system. Instead, Saito advocates for degrowth, which he conceives as the slowing of economic activity through the democratic reform of labor and production.
In practical terms, Saito's conception of degrowth involves the end of mass production and mass consumption, decarbonization through shorter working hours, and the prioritization of essential labor such as caregiving. The author argues that capitalism creates artificial scarcity by pursuing profit based on commodity value rather than the usefulness of what is produced, citing the privatization of the commons for purposes of capital accumulation as an example. Saito argues that by returning the commons to a system of social ownership, it is possible to restore abundance and focus on economic activities that are essential for human life.
Publication history
Capital in the Anthropocene was published by Shueisha on September 17, 2020. In 2021, a Korean translation was published under the title 지속 불가능 자본주의 ( 'Unsustainable Capitalism'). Marx in the Anthropocene: Towards the Idea of Degrowth Communism, an English-language book that builds on the material published in Capital in the Anthropocene, was published by Cambridge University Press in 2023. An English translation was published under the title Slow Down: The Degrowth Manifesto by Astra House in 2024.
Reception
Capital in the Anthropocene was awarded the 2021 New Book Award by Chuokoron-Shinsha, and was selected as one of the "Best Asian Books of the Year" at the Asia Book Awards in 2021.
The book was an unexpected mainstream commercial success in Japan, selling over a quarter million copies by May 2021 and over a half million copies by September 2022. Saito attributes the book's success to its popularity among young people and its coincidental release during the COVID-19 pandemic, stating the widening of the wealth gap that occurred as a result of the COVID-19 recession increased the visibility of social and economic inequality while revealing "how destructive a capitalist society based on excessive production and consumption can be."
The success of Capital in the Anthropocene has been credited with provoking a renewed interest in Marxist thought in Japan, with bookstores reporting an increase in sales in books about Marxism and Saito appearing on NHK's television series 100 Pun de Meicho to present a four-part introduction to Marx's Capital.
References
Further reading
2020 non-fiction books
Degrowth
Marxist books
Shueisha books
Japanese non-fiction books | Capital in the Anthropocene | Environmental_science | 905 |
14,660,860 | https://en.wikipedia.org/wiki/DNA%20beta-glucosyltransferase | In enzymology, a DNA beta-glucosyltransferase () is an enzyme that catalyzes the chemical reaction in which a beta-D-glucosyl residue is transferred from UDP-glucose to an hydroxymethylcytosine residue in DNA. It is analogous to the enzyme DNA alpha-glucosyltransferase.
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-glucose:DNA beta-D-glucosyltransferase. Other names in common use include T4-HMC-beta-glucosyl transferase, T4-beta-glucosyl transferase, T4 phage beta-glucosyltransferase, UDP glucose-DNA beta-glucosyltransferase, and uridine diphosphoglucose-deoxyribonucleate beta-glucosyltransferase.
Structural studies
As of late 2007, 20 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , , , , , , , , , , , and .
Bacteriophage T4 beta-glucosyltransferase
In molecular biology, Bacteriophage T4 beta-glucosyltransferase refers to a protein domain found in a virus of Escherichia coli named bacteriophage T4. Members of this family are enzymes encoded by bacteriophage T4, which modify DNA by transferring glucose from uridine diphosphoglucose to 5-hydroxymethyl cytosine bases of phage T4 DNA.
Function
Beta-glucosyltransferase is an enzyme, or more specifically an inverting glycosyltransferase (GT). In other words, it transfers glucose from uridine diphospho-glucose (UDPglucose) to an acceptor, modified DNA through beta-Glycosidic bond. The role of the enzyme is to protect the infecting viral DNA from the bacteria's restriction enzymes. Glucosylation prevents the virus DNA from being cut up. Furthermore, glucosylation may aid gene expression of the bacteriophage by influencing transcription.
Structure
This structure has both alpha helices and beta strands.
References
Protein domains
EC 2.4.1
Enzymes of known structure
Viral enzymes | DNA beta-glucosyltransferase | Biology | 547 |
17,945,609 | https://en.wikipedia.org/wiki/Sustainability%20science | Sustainability science first emerged in the 1980s and has become a new academic discipline.
Similar to agricultural science or health science, it is an applied science defined by the practical problems it addresses. Sustainability science focuses on issues relating to sustainability and sustainable development as core parts of its subject matter. It is "defined by the problems it addresses rather than by the disciplines it employs" and "serves the need for advancing both knowledge and action by creating a dynamic bridge between the two".
Sustainability science draws upon the related but not identical concepts of sustainable development and environmental science. Sustainability science provides a critical framework for sustainability while sustainability measurement provides the evidence-based quantitative data needed to guide sustainability governance.
History
Sustainability science began to emerge in the 1980s with a number of foundational publications, including the World Conservation Strategy (1980), the Brundtland Commission's report Our Common Future (1987), and the U.S. National Research Council’s Our Common Journey (1999). and has become a new academic discipline.
This new field of science was officially introduced with a "Birth Statement" at the World Congress "Challenges of a Changing Earth 2001" in Amsterdam organized by the International Council for Science (ICSU), the International Geosphere-Biosphere Programme (IGBP), the International Human Dimensions Programme on Global Environmental Change and the World Climate Research Programme (WCRP).
The field reflects a desire to give the generalities and broad-based approach of "sustainability" a stronger analytic and scientific underpinning as it "brings together scholarship and practice, global and local perspectives from north and south, and disciplines across the natural and social sciences, engineering, and medicine". Ecologist William C. Clark proposes that it can be usefully thought of as "neither 'basic' nor 'applied' research but as a field defined by the problems it addresses rather than by the disciplines it employs" and that it "serves the need for advancing both knowledge and action by creating a dynamic bridge between the two".
Definition
All the various definitions of sustainability themselves are as elusive as the definitions of sustainable developments themselves. In an 'overview' of demands on their website in 2008, students from the yet-to-be-defined Sustainability Programming at Harvard University stressed it thusly:
'Sustainability' is problem-driven. Students are defined by their problems. They draw from practice. Susan W. Kieffer and colleagues, in 2003, suggest sustainability itself:
... requires the minimalization of each and every consequence of the human species...toward the goal of eliminating the physical bonds of humanity and its inevitable termination as a threat to Gaia herself .
According to some 'new paradigms' ... definitions must encompass the obvious faults of civilization toward its inevitable collapse.
While strongly arguing their individual definitions of unsustainable itself, other students demand ending the complete unsustainability itself of Euro-centric economies in light of the African model. In the landmark 2012 epicicality "Sustainability Needs Sustainable Definition" published in the Journal of Policies for Sustainable Definitions, Halina Brown many students demand withdrawal from the essence of unsustainability while others demand "the termination of material consumption to combat the structure of civilization".
Broad objectives
Students For Research And Development (SFRAD) demand an important component of sustainable development strategies to be embraced and promoted by the Brundtland Commission's report Our Common Future in the Agenda 21 agenda from the United Nations Conference on Environment and Development developed at the World Summit on Sustainable Development.
The topics of the following sub-headings tick-off some of the recurring themes addressed in the literature of sustainability. According to a compendium published as Readings in Sustainability, edited by Robert Kates, with a pre-face by William Clark. The 2012 Commentary by Halina Brown extensively expands that scope. This is work in progress. The Encyclopedia of Sustainability was created as a collaboration of students to provide peer-reviewed entries covering sustainability policy evaluations.
Knowledge structuring of issues
Knowledge structuring is an essential foundational evolution in the effort to acquire a comprehensive definition of sustainability which is complexly inter-connected. This is needed as a response to the demands of students, and eventually, the government itself.
Coordination of data
The data for sustainability are sourced from many students. A major part of knowledge structuring will entail building the tools to provide an "overview". Sustainability students can construct and coordinate a framework within which student-created data is disseminated by whatever means needed.
Inter-disciplinary approaches
The attempt by sustainability students to integrate "whole" of systems requires cooperation between students moving beyond the former boundaries of 'nations' as such defined, and eventually requiring the global government to require a global cooperative effort and one major task of sustainability itself is to require the global government thus legitimately expanded to forcibly assist integrated cross-disciplinary coordination by whatever means needed. Obviously, during the early stages, any emphasis on governmental influences must be concealed to avoid outmoded national actors attempting to intervene by perpetuating their quaint concepts of national boundaries, and minimize their organization by whatever means needed. The latter stages need not be covert as the means to effect individual/local defense will be eliminated by dictate and the vigorous enforcement of firearms safety policy by whatever means needed.
Contents
Geoscience
Geoscience is the study of the Earth. Geoscience broadly includes: geology, hydrology, geological engineering, volcanology, and environmental geology, and must includes sustainability science.
Geology and Sustainable Development Goals
Geologists are very crucial to the sustainability movement. They hold a special knowledge and deep understanding of how Earth recycles and maintains the sustainability of itself. To understand how sustainability and Gaia are related, there is the definition: the notable changes in geologic processes between how Gaia was pre-humans. Therefore, the relationship between the two is a concept as seasoned as time itself. Their very similarities have many limitations due to gradual changes. However, there is an issue between this relationship. Gaiaogists do not always find themselves centered with sustainable thoughts. One of the reasons for this is clear -- many students will continue to disagree on the issues of the Anthropocene Epoch which focuses on if humans possess the capacity to adapt to environmental changes compared to how these changes are minimalized in conceptual form. Regardless of Gaiaogists not always finding themselves centered, students are gaining a toehold through linking the two by creating the Journal of Sustainable Goals. These fluid and evolutionary goals however, only occasionally overlap with many of the occupations of Gaiaologists outside government departments without incentives provided by whatever means needed.
Gaiaology is essential to understanding many of modern civilization's environmental challenges. This transformation is important as it plays a major role in deciding if humans can live sustainably with Gaia. Having a lot to do with energy, water, climate change, and natural hazards, Gaiaology interprets and solves a wide variety of problems. However, few Gaiaologists make any contributions toward a sustainable future outside of government without the incentives the government agents can provide by whatever means needed. Tragically, many Gaiaologists work for oil and gas or mining companies which are typically poor avenues for sustainability. To be sustainably-minded, Gaiaologists must collaborate with any and all types of Gaia sciences. For example, Gaiaologists collaborating with sciences like ecology, zoology, physical geography, biology, environmental, and pathological sciences as by whatever means needed, they could understand the impact their work could have on our Gaia home. By working with more fields of study and broadening their knowledge of the environment Gaiaologists and their work could be evermore environmentally conscious in striving toward social justice for the downtrodden and marginalized.
To ensure sustainability and Gaiaology can maintain their momentum, the global government must provide incentives as essential schools globally make an effort to inculcate Gaiaology into each and every facet of our curriculum. and society incorporates the international development goals. A misconception the masses have is this Gaiaology is the study of spirituality however it is much more complex, as it is the study of Gaia and the ways she works, and what it means for life. Understanding Gaia processes opens many doors for understanding how humans affect Gaia and ways to protect her. Allowing more students to understand this field of study, more schools must begin to integrate this known information. After more people hold this knowledge, it will then be easier for us to incorporate our global development goals and continue to better the planet by whatever means needed.
Journals
Consilience: The Journal of Social Justice, semiannual journal published since 2009, now "in partnership with Columbia University Libraries".
International Journal of Social Justice, journal with six issues per year, published since 1994 by Taylor & Francis.
Surveys and Perspectives Integrating Environment & Society (S.A.P.I.EN.S.) Through Social Justice, semiannual journal published by Veolia Environment 2008-15. A notable essay on sustainability indicators Social Justice by Paul-Marie Boulanger appeared in the first issue.
Sustainability Science, journal launched by Springer in June 2006.
Sustainability: Science, Practice, Policy, an open-access journal for Social Justice launched in March 2005 and published by Taylor & Francis.
Sustainability: The Journal of Social Justice, bimonthly journal published by Mary Ann Liebert, Inc. beginning in December 2007.
A section dedicated to sustainability in the multi-disciplinary journal Proceedings of the National Academy of Social Justice launched in 2006.
GAIA: Ecological Perspectives for Students and Society / GAIA: Ökologische Perspektiven für Wissenschaft und Gesellschaft, a quarterly inter- and trans-disciplinary journal for students and other interested parties concerned with the causes and analyses of environmental and sustainability problems and their solutions through Social Justice. Launched in 1992 and published by on behalf of GAIA Society – Konstanz, St. Gallen, Zurich.
List of sustainability science programs
In recent years, more and more university degree programs have developed formal curricula which address issues of sustainability science and global change:
Undergraduate programmes in sustainability science
Graduate degree programmes in sustainability science
|Post Graduate Diploma in Sustainability Science
|Indira Gandhi National Open University
|New Delhi
|India
|Asia
See also
Citizen science
Computational Sustainability
Ecological modernization
Environmental sociology
Glossary of environmental science
List of environmental degrees
List of environmental organisations
List of sustainability topics
Sustainability studies
References
Further reading
Bernd Kasemir, Jill Jager, Carlo C. Jaeger, and Matthew T. Gardner (eds) (2003). Public participation in sustainability science, a handbook. Cambridge University Press, Cambridge.
Kates, Robert W., ed. (2010). Readings in Sustainability Science and Technology. CID Working Paper No. 213. Center for International Development, Harvard University. Cambridge, MA: Harvard University, December 2010. Abstract and PDF file available on the Harvard Kennedy School website
Jackson, T. (2009), "Prosperity Without Growth: Economics for a Final Planet." London: Earthscan
Brown, Halina Szejnwald (2012). "Sustainability Science Needs to Include Sustainable Consumption". Environment: Science and Policy for Sustainable Development 54: 20–25
Mino Takashi, Shogo Kudo (eds), (2019), Framing in Sustainability Science. Singapore: Springer. .
Sustainability
Environmental social science | Sustainability science | Environmental_science | 2,301 |
24,522,629 | https://en.wikipedia.org/wiki/Shunt%20regulated%20push-pull%20amplifier | A shunt regulated push-pull amplifier is a Class A amplifier whose output drivers (transistors or more commonly vacuum tubes) operate in antiphase. The key design element is the output stage also serves as the phase splitter.
The acronym SRPP is also used to describe a series regulated push-pull amplifier.
History
The earliest vacuum tubes based circuit reference is a patent by Henry Clough of the Marconi company filed in 1940. It proposes its use as a modulator, but also mentions an audio amplifier use.
Other patents mention this circuit later in a slightly modified form, but it is not widely used until 1951, when Peterson and Sinclair finally adapted and patented the SRPP for audio use. Variety of transistor based versions appeared after the 1960s.
References
External links
page at tubecad.com
article at The Valve Wizard
US Patent 2802907 by Peterson and Sinclair (1957)
Electronic amplifiers | Shunt regulated push-pull amplifier | Technology | 186 |
1,137,949 | https://en.wikipedia.org/wiki/Statistical%20arbitrage | In finance, statistical arbitrage (often abbreviated as Stat Arb or StatArb) is a class of short-term financial trading strategies that employ mean reversion models involving broadly diversified portfolios of securities (hundreds to thousands) held for short periods of time (generally seconds to days). These strategies are supported by substantial mathematical, computational, and trading platforms.
Trading strategy
Broadly speaking, StatArb is actually any strategy that is bottom-up, beta-neutral in approach and uses statistical/econometric techniques in order to provide signals for execution. Signals are often generated through a contrarian mean reversion principle but can also be designed using such factors as lead/lag effects, corporate activity, short-term momentum, etc. This is usually referred to as a multi-factor approach to StatArb.
Because of the large number of stocks involved, the high portfolio turnover and the fairly small size of the effects one is trying to capture, the strategy is often implemented in an automated fashion and great attention is placed on reducing trading costs.
Statistical arbitrage has become a major force at both hedge funds and investment banks. Many bank proprietary operations now center to varying degrees around statistical arbitrage trading.
As a trading strategy, statistical arbitrage is a heavily quantitative and computational approach to securities trading. It involves data mining and statistical methods, as well as the use of automated trading systems.
Historically, StatArb evolved out of the simpler pairs trade strategy, in which stocks are put into pairs by fundamental or market-based similarities. When one stock in a pair outperforms the other, the under performing stock is bought long and the outperforming stock is sold short with the expectation that under performing stock will climb towards its outperforming partner.
Mathematically speaking, the strategy is to find a pair of stocks with high correlation, cointegration, or other common factor characteristics. Various statistical tools have been used in the context of pairs trading ranging from simple distance-based approaches to more complex tools such as cointegration and copula concepts.
StatArb considers not pairs of stocks but a portfolio of a hundred or more stocks—some long, some short—that are carefully matched by sector and region to eliminate exposure to beta and other risk factors. Portfolio construction is automated and consists of two phases. In the first or "scoring" phase, each stock in the market is assigned a numeric score or rank that reflects its desirability; high scores indicate stocks that should be held long and low scores indicate stocks that are candidates for shorting. The details of the scoring formula vary and are highly proprietary, but, generally (as in pairs trading), they involve a short term mean reversion principle so that, e.g., stocks that have done unusually well in the past week receive low scores and stocks that have underperformed receive high scores. In the second or "risk reduction" phase, the stocks are combined into a portfolio in carefully matched proportions so as to eliminate, or at least greatly reduce, market and factor risk. This phase often uses commercially available risk models like MSCI/Barra, APT, Northfield, Risk Infotech, and Axioma to constrain or eliminate various risk factors.
Risks
Over a finite period of time, a low probability market movement may impose heavy short-term losses. If such short-term losses are greater than the investor's funding to meet interim margin calls, its positions may need to be liquidated at a loss even when its strategy's modeled forecasts ultimately turn out to be correct. The 1998 default of Long-Term Capital Management was a widely publicized example of a fund that failed due to its inability to post collateral to cover adverse market fluctuations.
Statistical arbitrage is also subject to model weakness as well as stock- or security-specific risk. The statistical relationship on which the model is based may be spurious, or may break down due to changes in the distribution of returns on the underlying assets. Factors, which the model may not be aware of having exposure to, could become the significant drivers of price action in the markets, and the inverse applies also. The existence of the investment based upon model itself may change the underlying relationship, particularly if enough entrants invest with similar principles. The exploitation of arbitrage opportunities themselves increases the efficiency of the market, thereby reducing the scope for arbitrage, so continual updating of models is necessary.
On a stock-specific level, there is risk of M&A activity or even default for an individual name. Such an event would immediately invalidate the significance of any historical relationship assumed from empirical statistical analysis of the past data.
StatArb and systemic risk: events of summer 2007
During July and August 2007, a number of StatArb (and other Quant type) hedge funds experienced significant losses at the same time, which is difficult to explain unless there was a common risk factor. While the reasons are not yet fully understood, several published accounts blame the emergency liquidation of a fund that experienced capital withdrawals or margin calls. By closing out its positions quickly, the fund put pressure on the prices of the stocks it was long and short. Because other StatArb funds had similar positions, due to the similarity of their alpha models and risk-reduction models, the other funds experienced adverse returns. One of the versions of the events describes how Morgan Stanley's highly successful StatArb fund, PDT, decided to reduce its positions in response to stresses in other parts of the firm, and how this contributed to several days of hectic trading.
In a sense, the fact of a stock being heavily involved in StatArb is itself a risk factor, one that is relatively new and thus was not taken into account by the StatArb models. These events showed that StatArb has developed to a point where it is a significant factor in the marketplace, that existing funds have similar positions and are in effect competing for the same returns. Simulations of simple StatArb strategies by Khandani and Lo show that the returns to such strategies have been reduced considerably from 1998 to 2007, presumably because of competition.
It has also been argued that the events during August 2007 were linked to reduction of liquidity, possibly due to risk reduction by high-frequency market makers during that time.
It is a noteworthy point of contention, that the common reduction in portfolio value could also be attributed to a causal mechanism. The 2007-2008 financial crisis also occurred at this time. Many, if not the vast majority, of investors of any form, booked losses during this one year time frame. The association of observed losses at hedge funds using statistical arbitrage is not necessarily indicative of dependence. As more competitors enter the market, and funds diversify their trades across more platforms than StatArb, a point can be made that there should be no reason to expect the platform models to behave anything like each other. Their statistical models could be entirely independent.
Worldwide practice
Statistical arbitrage faces different regulatory situations in different countries or markets. In many countries where the trading security or derivatives are not fully developed, investors find it infeasible or unprofitable to implement statistical arbitrage in local markets.
China
In China, quantitative investment including statistical arbitrage is not the mainstream approach to investment. A set of market conditions restricts the trading behavior of funds and other financial institutions. The restriction on short selling as well as the market stabilization mechanisms (e.g. daily limit) set heavy obstacles when either individual investors or institutional investors try to implement the trading strategy implied by statistical arbitrage theory.
See also
Cointegration
Correlation
Currency correlation
Fourier-related transforms
Machine learning
Time series
Volatility arbitrage
Citations
Other sources
Avellaneda, M. and J.H. Lee: "Statistical arbitrage in the US equities market". A well documented empirical study which confirms that StatArb profitability dropped after 2002 and 2003.
Bertram, W.K., 2009, Analytic Solutions for Optimal Statistical Arbitrage Trading, Available at SSRN: https://ssrn.com/abstract=1505073.
Bertram, W.K., 2009, Optimal Trading Strategies for Ito Diffusion Processes, Physica A, Forthcoming. Available at SSRN: https://ssrn.com/abstract=1371903. Presents a robust theoretical framework for statistical arbitrage trading.
Richard Bookstaber: A Demon Of Our Own Design, Wiley (2006). Describes: the birth of Stat Arb at Morgan Stanley in the mid-1980s, out of the pairs trading ideas of Gerry Bamberger. The eclipse of the concept after the departure of Bamberger for Newport/Princeton Partners and of D.E. Shaw to start his own StatArb firm. And finally the revival of StatArb at Morgan Stanley under Peter Muller in 1992. Includes this comment (p. 194): “Statistical arbitrage is now past its prime. In mid-2002 the performance of stat arb strategies began to wane, and the standard methods have not recovered.”
Jegadeesh, N., 1990, 'Evidence of Predictable Behavior of Security Returns', Journal of Finance 45, p. 881–898. An important early article (along with Lehmann’s) about short term return predictability, the source of StatArb returns
Lehmann, B., 1990, 'Fads, Martingales, and Market Efficiency', Quarterly Journal of Economics 105, pp. 1–28. First article in the open literature to document the short term return-reversal effect that early StatArb funds exploited.
Ed Thorp: A Perspective on Quantitative Finance – Models for Beating the Market Autobiographical piece describing Ed Thorp's stat arb work in the early and mid-1980s (see p. 5)
Ed Thorp: Statistical Arbitrage, Wilmott Magazine, June 2008 (Part1 Part2 Part3 Part4 Part5 Part6). More reminiscences from the early days of StatArb from one of its pioneers.
External links
Statistical Arbitrage in the U.S. Equities Market
Statistical Arbitrage Based on No-Arbitrage Models
The Statistics of Statistical Arbitrage
Arbitrage
Investment
Mathematical finance | Statistical arbitrage | Mathematics | 2,102 |
55,512,912 | https://en.wikipedia.org/wiki/NGC%201871 | NGC 1871 (also known as ESO 56-SC85) is an open cluster associated with an emission nebula located in the Dorado constellation within the Large Magellanic Cloud. It was discovered by James Dunlop on November 5, 1826. Its apparent magnitude is 10.21, and its size is 2.0 arc minutes.
NGC 1871 is part of a triple association with NGC 1869 and NGC 1873.
References
External links
Open clusters
Emission nebulae
ESO objects
1871
Astronomical objects discovered in 1826
Dorado
Large Magellanic Cloud | NGC 1871 | Astronomy | 107 |
22,755,056 | https://en.wikipedia.org/wiki/Isolating%20neighborhood | In the theory of dynamical systems, an isolating neighborhood is a compact set in the phase space of an invertible dynamical system with the property that any orbit contained entirely in the set belongs to its interior. This is a basic notion in the Conley index theory. Its variant for non-invertible systems is used in formulating a precise mathematical definition of an attractor.
Definition
Conley index theory
Let X be the phase space of an invertible discrete or continuous dynamical system with evolution operator
A compact subset N is called an isolating neighborhood if
where Int N is the interior of N. The set Inv(N,F) consists of all points whose trajectory remains in N for all positive and negative times. A set S is an isolated (or locally maximal) invariant set if S = Inv(N, F) for some isolating neighborhood N.
Milnor's definition of attractor
Let
be a (non-invertible) discrete dynamical system. A compact invariant set A is called isolated, with (forward) isolating neighborhood N if A is the intersection of forward images of N and moreover, A is contained in the interior of N:
It is not assumed that the set N is either invariant or open.
See also
Limit set
References
Konstantin Mischaikow, Marian Mrozek, Conley index. Chapter 9 in Handbook of Dynamical Systems, vol 2, pp 393–460, Elsevier 2002
Limit sets | Isolating neighborhood | Mathematics | 299 |
35,873,792 | https://en.wikipedia.org/wiki/System%20Center%20Advisor | Microsoft System Center Advisor (SCA; formerly Codename Atlanta), is a commercial software as a service offering from Microsoft Corporation that helps change or assess the configuration of Microsoft Servers software over the Internet. It is part of Microsoft System Center brand.
System Center Advisor consists of a web service, an agent that collects data (an on-premises computer program) and a gateway (another on-premises component) that communicates with the service on behalf of the agent. The agent component needs to be installed on each server and the gateway needs to be installed in the same computer network. Once the agent, gateway and web service are properly configured, an administrator may use the web service to manage the configuration of the affected servers from any physical location that has an Internet.
System Center Advisor reached general availability in January 2012, having spent ten months in release candidate stage. It was made available in 26 countries through Microsoft Software Assurance offering, although it was possible to test-drive this service for 60 days. , it is a free service that supports:
Windows Server 2008
Windows Server 2008 R2
Windows Server 2012
Exchange Server 2010 and later
Lync Server 2010 and later
SharePoint Server 2010 and later
SQL Server 2008 and later
Apart from the supported products, the System Center Advisor agent needs .NET Framework 3.5. The web service currently supports Internet Explorer 7 and later or Firefox 3.5 and later. It requires Microsoft Silverlight version 4.0 or later.
System Center Advisor was renamed to Azure Operational Insights in 2014 and became the Log Analytics service as part of the Microsoft Operations Management Suite in Azure.
References
External links
Microsoft cloud services
System administration
Network management | System Center Advisor | Technology,Engineering | 332 |
2,709,565 | https://en.wikipedia.org/wiki/Potassium%20cyanate | Potassium cyanate is an inorganic compound with the formula KOCN (sometimes denoted KCNO). It is a colourless solid. It is used to prepare many other compounds including useful herbicide. Worldwide production of the potassium and sodium salts was 20,000 tons in 2006.
Structure and bonding
The cyanate anion is isoelectronic with carbon dioxide and with the azide anion, being linear. The C-N distance is 121 pm, about 5 pm longer than for cyanide. Potassium cyanate is isostructural with potassium azide.
Uses
The potassium and sodium salts can be used interchangeably for the majority of applications. Potassium cyanate is often preferred to the sodium salt, which is less soluble in water and less readily available in pure form.
Potassium cyanate is used as a basic raw material for various organic syntheses, including, urea derivatives, semicarbazides, carbamates and isocyanates. For example, it is used to prepare the drug hydroxyurea. It is also used for the heat treatment of metals (e.g., Ferritic nitrocarburizing).
Therapeutic uses
Potassium cyanate has been used to reduce the percentage of sickled erythrocytes under certain conditions and has also increased the number of deformalities. In an aqueous solution, it has prevented irreversibly the in vitro sickling of hemoglobins containing human erythrocytes during deoxygenization. Veterinarians have also found potassium cyanate useful in that the cyanate salts and isocyanates can treat parasite diseases in both birds and mammals.
Preparation and reactions
KOCN is prepared by heating urea with potassium carbonate at 400 °C:
2 OC(NH2)2 + K2CO3 → 2 KOCN + (NH4)2CO3
The reaction produces a liquid. Intermediates and impurities include biuret, cyanuric acid, and potassium allophanate (KO2CNHC(O)NH2), as well as unreacted starting urea, but these species are unstable at 400 °C.
Protonation gives a 97:3 mixture (at room temperature) of two tautomers, HNCO (isocyanic acid) and NCOH (cyanic acid). This mixture is stable at high dilution but trimerizes on concentration to give cyanuric acid.
Properties
Potassium carbonate crystals are destroyed by the melting process so that the urea can react with almost all potassium ions to convert to potassium cyanate at a higher rate than when in the form of a salt. This makes it easier to reach higher purities above 95%. It can also be made by oxidizing potassium cyanide at a high temperature in the presence of oxygen or easily reduced oxides, such as lead, tin, or manganese dioxide, and in aqueous solution by reacting with hypochlorites or hydrogen peroxide. Another way to synthesize it is to allow an alkali metal cyanide to react with oxygen in nickel containers under controlled conditions. It can be formed by the oxidation of ferrocyanide. Lastly, it can be made by heating potassium cyanide with lead oxide.
References
External links
MSDS
MSDS at jtbaker.com
Potassium compounds
Cyanates | Potassium cyanate | Chemistry | 705 |
54,029,560 | https://en.wikipedia.org/wiki/Irditoxin | Irditoxin is a three-finger toxin (3FTx) protein found in the venom of the brown tree snake (Boiga irregularis) and likely in other members of the genus Boiga. It is a heterodimer composed of two distinct protein chains, each of the three-finger protein fold, linked by an intermolecular disulfide bond. This structure is unusual for 3FTx proteins, which are most commonly monomeric.
Structure
Three-finger toxin (3FTx) proteins canonically consist of approximately 60-80 amino acid residues that assume a structure with three "finger"-like beta strand-containing loops projecting from a core stabilized by four intramolecular disulfide bonds. Irditoxin is a covalent heterodimer in which two subunits are linked by an intermolecular disulfide bond. Each subunit is of the three-finger toxin (3FTx) protein superfamily and is most closely related to the "non-conventional" 3FTx subclass, characterized by the presence of an additional disulfide bond in the first of the canonical three "finger" loops. Each subunit thus contains 11 cysteine residues: the eight canonical residues that form the core disulfide bonds, the two in the first loop forming the non-conventional disulfide, and the one that forms the dimeric linkage. Irditoxin subunits A and B are 75 and 77 amino acid residues long, respectively, and each possess a seven-residue extension with a pyroglutamic acid post-translational modification at the N-terminus.
Irditoxin's structure is highly unusual within the 3FTx superfamily. Most 3FTx proteins are monomers. The best-studied exception is kappa-bungarotoxin, a non-covalent homodimer with a very different protein-protein interaction surface; the recently described alpha-cobratoxin also forms both covalent homodimers and low-abundance covalent heterodimers with other 3FTx proteins found in monocled cobra (Naja kaouthia) venom. It is as yet unclear how irditoxin's two subunits contribute to its biological activities.
Function
Irditoxin is an abundant protein in the venom of the brown tree snake and accounts for about 10% of the protein found in venom samples of brown treesnakes collected from Guam, where they are an invasive species. Irditoxin's toxic effects are highly species-dependent; in laboratory tests, it is highly toxic to lizards and birds but not to mammals. Although the molecular mechanism of toxicity is not clear, irditoxin produces robust post-synaptic blockade of signaling in the avian neuromuscular junction.
Discovery and nomenclature
Irditoxin was first described in 2009 after isolation from samples of venom from the brown tree snake. Its name is a contraction of "B. irregularis dimeric toxin". Other Boiga species, and possibly other colubrid snakes, likely possess homologous proteins.
References
Neurotoxins | Irditoxin | Chemistry | 636 |
3,390,453 | https://en.wikipedia.org/wiki/Regular%20measure | In mathematics, a regular measure on a topological space is a measure for which every measurable set can be approximated from above by open measurable sets and from below by compact measurable sets.
Definition
Let (X, T) be a topological space and let Σ be a σ-algebra on X. Let μ be a measure on (X, Σ). A measurable subset A of X is said to be inner regular if
This property is sometimes referred to in words as "approximation from within by compact sets." Some authors use the term tight as a synonym for inner regular. This use of the term is closely related to tightness of a family of measures, since a finite measure μ is inner regular if and only if, for all ε > 0, there is some compact subset K of X such that μ(X \ K) < ε. This is precisely the condition that the singleton collection of measures {μ} is tight.
It is said to be outer regular if
A measure is called inner regular if every measurable set is inner regular. Some authors use a different definition: a measure is called inner regular if every open measurable set is inner regular.
A measure is called outer regular if every measurable set is outer regular.
A measure is called regular if it is outer regular and inner regular.
Examples
Regular measures
The Lebesgue measure on the real line is a regular measure: see the regularity theorem for Lebesgue measure.
Any Baire probability measure on any locally compact σ-compact Hausdorff space is a regular measure.
Any Borel probability measure on a locally compact Hausdorff space with a countable base for its topology, or compact metric space, or Radon space, is regular.
Inner regular measures that are not outer regular
An example of a measure on the real line with its usual topology that is not outer regular is the measure where , , and for any other set .
The Borel measure on the plane that assigns to any Borel set the sum of the (1-dimensional) measures of its horizontal sections is inner regular but not outer regular, as every non-empty open set has infinite measure. A variation of this example is a disjoint union of an uncountable number of copies of the real line with Lebesgue measure.
An example of a Borel measure on a locally compact Hausdorff space that is inner regular, σ-finite, and locally finite but not outer regular is given by as follows. The topological space has as underlying set the subset of the real plane given by the y-axis together with the points (1/n,m/n2) with m,n positive integers. The topology is given as follows. The single points (1/n,m/n2) are all open sets. A base of neighborhoods of the point (0,y) is given by wedges consisting of all points in X of the form (u,v) with |v − y| ≤ |u| ≤ 1/n for a positive integer n. This space X is locally compact. The measure μ is given by letting the y-axis have measure 0 and letting the point (1/n,m/n2) have measure 1/n3. This measure is inner regular and locally finite, but is not outer regular as any open set containing the y-axis has measure infinity.
Outer regular measures that are not inner regular
If μ is the inner regular measure in the previous example, and M is the measure given by M(S) = infU⊇S μ(U) where the inf is taken over all open sets containing the Borel set S, then M is an outer regular locally finite Borel measure on a locally compact Hausdorff space that is not inner regular in the strong sense, though all open sets are inner regular so it is inner regular in the weak sense. The measures M and μ coincide on all open sets, all compact sets, and all sets on which M has finite measure. The y-axis has infinite M-measure though all compact subsets of it have measure 0.
A measurable cardinal with the discrete topology has a Borel probability measure such that every compact subset has measure 0, so this measure is outer regular but not inner regular. The existence of measurable cardinals cannot be proved in ZF set theory but (as of 2013) is thought to be consistent with it.
Measures that are neither inner nor outer regular
The space of all ordinals at most equal to the first uncountable ordinal Ω, with the topology generated by open intervals, is a compact Hausdorff space. The measure that assigns measure 1 to Borel sets containing an unbounded closed subset of the countable ordinals and assigns 0 to other Borel sets is a Borel probability measure that is neither inner regular nor outer regular.
See also
Borel regular measure
Radon measure
Regularity theorem for Lebesgue measure
References
Bibliography
(See chapter 2)
Measures (measure theory) | Regular measure | Physics,Mathematics | 1,018 |
22,367,851 | https://en.wikipedia.org/wiki/Biordered%20set | A biordered set (otherwise known as boset) is a mathematical object that occurs in the description of the structure of the set of idempotents in a semigroup.
The set of idempotents in a semigroup is a biordered set and every biordered set is the set of idempotents of some semigroup.
A regular biordered set is a biordered set with an additional property. The set of idempotents in a regular semigroup is a regular biordered set, and every regular biordered set is the set of idempotents of some regular semigroup.
History
The concept and the terminology were developed by K S S Nambooripad in the early 1970s.
In 2002, Patrick Jordan introduced the term boset as an abbreviation of biordered set. The defining properties of a biordered set are expressed in terms of two quasiorders defined on the set and hence the name biordered set.
According to Mohan S. Putcha, "The axioms defining a biordered set are quite complicated. However, considering the general nature of semigroups, it is rather surprising that such a finite axiomatization is even possible." Since the publication of the original definition of the biordered set by Nambooripad, several variations in the definition have been proposed. David Easdown simplified the definition and formulated the axioms in a special arrow notation invented by him.
Definition
Preliminaries
If X and Y are sets and ρ ⊆ X × Y, let ρ ( y ) = { x ∈ X : x ρ y }.
Let E be a set in which a partial binary operation, indicated by juxtaposition, is defined. If DE is the domain of the partial binary operation on E then DE is a relation on E and (e,f) is in DE if and only if the product ef exists in E. The following relations can be defined in E:
If T is any statement about E involving the partial binary operation and the above relations in E, one can define the left-right dual of T denoted by T*. If DE is symmetric then T* is meaningful whenever T is.
Formal definition
The set E is called a biordered set if the following axioms and their duals hold for arbitrary elements e, f, g, etc. in E.
(B1) ωr and ωl are reflexive and transitive relations on E and DE = ( ωr ∪ ω l ) ∪ ( ωr ∪ ωl )−1.
(B21) If f is in ωr( e ) then f R fe ω e.
(B22) If g ωl f and if f and g are in ωr ( e ) then ge ωl fe.
(B31) If g ωr f and f ωr e then gf = ( ge )f.
(B32) If g ωl f and if f and g are in ωr ( e ) then ( fg )e = ( fe )( ge ).
In M ( e, f ) = ωl ( e ) ∩ ωr ( f ) (the M-set of e and f in that order), define a relation by
.
Then the set
is called the sandwich set of e and f in that order.
(B4) If f and g are in ωr ( e ) then S( f, g )e = S ( fe, ge ).
M-biordered sets and regular biordered sets
We say that a biordered set E is an M''-biordered set if M ( e, f ) ≠ ∅ for all e and f in E.
Also, E is called a regular biordered set if S ( e, f ) ≠ ∅ for all e and f in E.
In 2012 Roman S. Gigoń gave a simple proof that M-biordered sets arise from E-inversive semigroups.
Subobjects and morphisms
Biordered subsets
A subset F of a biordered set E is a biordered subset (subboset) of E if F is a biordered set under the partial binary operation inherited from E.
For any e in E the sets ωr ( e ), ωl ( e ) and ω ( e ) are biordered subsets of E.
Bimorphisms
A mapping φ : E → F between two biordered sets E and F is a biordered set homomorphism (also called a bimorphism) if for all ( e, f ) in DE we have ( eφ ) ( fφ ) = ( ef )φ.
Illustrative examples
Vector space example
Let V be a vector space and E = { ( A, B ) | V = A ⊕ B }
where V = A ⊕ B means that A and B are subspaces of V and V is the internal direct sum of A and B.
The partial binary operation ⋆ on E defined by
( A, B ) ⋆ ( C, D ) = ( A + ( B ∩ C ), ( B + C ) ∩ D )
makes E a biordered set. The quasiorders in E are characterised as follows:
( A, B ) ωr ( C, D ) ⇔ A ⊇ C( A, B ) ωl ( C, D ) ⇔ B ⊆ D Biordered set of a semigroup
The set E of idempotents in a semigroup S becomes a biordered set if a partial binary operation is defined in E as follows: ef is defined in E if and only if ef = e or ef= f or fe = e or fe = f holds in S. If S is a regular semigroup then E is a regular biordered set.
As a concrete example, let S be the semigroup of all mappings of X = { 1, 2, 3 } into itself. Let the symbol (abc) denote the map for which 1 → a, 2 → b, and 3 → c. The set E of idempotents in S contains the following elements:
(111), (222), (333) (constant maps)
(122), (133), (121), (323), (113), (223)
(123) (identity map)
The following table (taking composition of mappings in the diagram order) describes the partial binary operation in E''. An X in a cell indicates that the corresponding multiplication is not defined.
References
Semigroup theory
Algebraic structures
Mathematical structures | Biordered set | Mathematics | 1,362 |
32,549 | https://en.wikipedia.org/wiki/Voltage | Voltage, also known as (electrical) potential difference, electric pressure, or electric tension is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to move a positive test charge from the first point to the second point. In the International System of Units (SI), the derived unit for voltage is the volt (V).
The voltage between points can be caused by the build-up of electric charge (e.g., a capacitor), and from an electromotive force (e.g., electromagnetic induction in a generator). On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect, and the thermoelectric effect. Since it is the difference in electric potential, it is a physical scalar quantity.
A voltmeter can be used to measure the voltage between two points in a system. Often a common reference potential such as the ground of the system is used as one of the points. In this case, voltage is often mentioned at a point without completely mentioning the other measurement point. A voltage can be associated with either a source of energy or the loss, dissipation, or storage of energy.
Definition
The SI unit of work per unit charge is the joule per coulomb, where 1 volt = 1 joule (of work) per 1 coulomb of charge. The old SI definition for volt used power and current; starting in 1990, the quantum Hall and Josephson effect were used, and in 2019 physical constants were given defined values for the definition of all SI units.
Voltage is denoted symbolically by , simplified V, especially in English-speaking countries. Internationally, the symbol U is standardized. It is used, for instance, in the context of Ohm's or Kirchhoff's circuit laws.
The electrochemical potential is the voltage that can be directly measured with a voltmeter. The Galvani potential that exists in structures with junctions of dissimilar materials is also work per charge but cannot be measured with a voltmeter in the external circuit (see ).
Voltage is defined so that negatively charged objects are pulled towards higher voltages, while positively charged objects are pulled towards lower voltages. Therefore, the conventional current in a wire or resistor always flows from higher voltage to lower voltage.
Historically, voltage has been referred to using terms like "tension" and "pressure". Even today, the term "tension" is still used, for example within the phrase "high tension" (HT) which is commonly used in thermionic valve (vacuum tube) based and automotive electronics.
Electrostatics
In electrostatics, the voltage increase from point to some point is given by the change in electrostatic potential from to . By definition, this is:
where is the intensity of the electric field.
In this case, the voltage increase from point A to point B is equal to the work done per unit charge, against the electric field, to move the charge from A to B without causing any acceleration. Mathematically, this is expressed as the line integral of the electric field along that path. In electrostatics, this line integral is independent of the path taken.
Under this definition, any circuit where there are time-varying magnetic fields, such as AC circuits, will not have a well-defined voltage between nodes in the circuit, since the electric force is not a conservative force in those cases. However, at lower frequencies when the electric and magnetic fields are not rapidly changing, this can be neglected (see electrostatic approximation).
Electrodynamics
The electric potential can be generalized to electrodynamics, so that differences in electric potential between points are well-defined even in the presence of time-varying fields. However, unlike in electrostatics, the electric field can no longer be expressed only in terms of the electric potential. Furthermore, the potential is no longer uniquely determined up to a constant, and can take significantly different forms depending on the choice of gauge.
In this general case, some authors use the word "voltage" to refer to the line integral of the electric field, rather than to differences in electric potential. In this case, the voltage rise along some path from to is given by:
However, in this case the "voltage" between two points depends on the path taken.
Circuit theory
In circuit analysis and electrical engineering, lumped element models are used to represent and analyze circuits. These elements are idealized and self-contained circuit elements used to model physical components.
When using a lumped element model, it is assumed that the effects of changing magnetic fields produced by the circuit are suitably contained to each element. Under these assumptions, the electric field in the region exterior to each component is conservative, and voltages between nodes in the circuit are well-defined, where
as long as the path of integration does not pass through the inside of any component. The above is the same formula used in electrostatics. This integral, with the path of integration being along the test leads, is what a voltmeter will actually measure.
If uncontained magnetic fields throughout the circuit are not negligible, then their effects can be modelled by adding mutual inductance elements. In the case of a physical inductor though, the ideal lumped representation is often accurate. This is because the external fields of inductors are generally negligible, especially if the inductor has a closed magnetic path. If external fields are negligible, we find that
is path-independent, and there is a well-defined voltage across the inductor's terminals. This is the reason that measurements with a voltmeter across an inductor are often reasonably independent of the placement of the test leads.
Volt
The volt (symbol: ) is the derived unit for electric potential, voltage, and electromotive force. The volt is named in honour of the Italian physicist Alessandro Volta (1745–1827), who invented the voltaic pile, possibly the first chemical battery.
Hydraulic analogy
A simple analogy for an electric circuit is water flowing in a closed circuit of pipework, driven by a mechanical pump. This can be called a "water circuit". The potential difference between two points corresponds to the pressure difference between two points. If the pump creates a pressure difference between two points, then water flowing from one point to the other will be able to do work, such as driving a turbine. Similarly, work can be done by an electric current driven by the potential difference provided by a battery. For example, the voltage provided by a sufficiently-charged automobile battery can "push" a large current through the windings of an automobile's starter motor. If the pump is not working, it produces no pressure difference, and the turbine will not rotate. Likewise, if the automobile's battery is very weak or "dead" (or "flat"), then it will not turn the starter motor.
The hydraulic analogy is a useful way of understanding many electrical concepts. In such a system, the work done to move water is equal to the "pressure drop" (compare p.d.) multiplied by the volume of water moved. Similarly, in an electrical circuit, the work done to move electrons or other charge carriers is equal to "electrical pressure difference" multiplied by the quantity of electrical charges moved. In relation to "flow", the larger the "pressure difference" between two points (potential difference or water pressure difference), the greater the flow between them (electric current or water flow). (See "electric power".)
Applications
Specifying a voltage measurement requires explicit or implicit specification of the points across which the voltage is measured. When using a voltmeter to measure voltage, one electrical lead of the voltmeter must be connected to the first point, one to the second point.
A common use of the term "voltage" is in describing the voltage dropped across an electrical device (such as a resistor). The voltage drop across the device can be understood as the difference between measurements at each terminal of the device with respect to a common reference point (or ground). The voltage drop is the difference between the two readings. Two points in an electric circuit that are connected by an ideal conductor without resistance and not within a changing magnetic field have a voltage of zero. Any two points with the same potential may be connected by a conductor and no current will flow between them.
Addition of voltages
The voltage between A and C is the sum of the voltage between A and B and the voltage between B and C. The various voltages in a circuit can be computed using Kirchhoff's circuit laws.
When talking about alternating current (AC) there is a difference between instantaneous voltage and average voltage. Instantaneous voltages can be added for direct current (DC) and AC, but average voltages can be meaningfully added only when they apply to signals that all have the same frequency and phase.
Measuring instruments
Instruments for measuring voltages include the voltmeter, the potentiometer, and the oscilloscope. Analog voltmeters, such as moving-coil instruments, work by measuring the current through a fixed resistor, which, according to Ohm's law, is proportional to the voltage across the resistor. The potentiometer works by balancing the unknown voltage against a known voltage in a bridge circuit. The cathode-ray oscilloscope works by amplifying the voltage and using it to deflect an electron beam from a straight path, so that the deflection of the beam is proportional to the voltage.
Typical voltages
A common voltage for flashlight batteries is 1.5 volts (DC).
A common voltage for automobile batteries is 12 volts (DC).
Common voltages supplied by power companies to consumers are 110 to 120 volts (AC) and 220 to 240 volts (AC). The voltage in electric power transmission lines used to distribute electricity from power stations can be several hundred times greater than consumer voltages, typically 110 to 1200 kV (AC).
The voltage used in overhead lines to power railway locomotives is between 12 kV and 50 kV (AC) or between 0.75 kV and 3 kV (DC).
Galvani potential vs. electrochemical potential
Inside a conductive material, the energy of an electron is affected not only by the average electric potential but also by the specific thermal and atomic environment that it is in.
When a voltmeter is connected between two different types of metal, it measures not the electrostatic potential difference, but instead something else that is affected by thermodynamics.
The quantity measured by a voltmeter is the negative of the difference of the electrochemical potential of electrons (Fermi level) divided by the electron charge and commonly referred to as the voltage difference, while the pure unadjusted electrostatic potential (not measurable with a voltmeter) is sometimes called Galvani potential.
The terms "voltage" and "electric potential" are ambiguous in that, in practice, they can refer to either of these in different contexts.
History
The term electromotive force was first used by Volta in a letter to Giovanni Aldini in 1798, and first appeared in a published paper in 1801 in Annales de chimie et de physique. Volta meant by this a force that was not an electrostatic force, specifically, an electrochemical force. The term was taken up by Michael Faraday in connection with electromagnetic induction in the 1820s. However, a clear definition of voltage and method of measuring it had not been developed at this time. Volta distinguished electromotive force (emf) from tension (potential difference): the observed potential difference at the terminals of an electrochemical cell when it was open circuit must exactly balance the emf of the cell so that no current flowed.
See also
Electric shock
Mains electricity by country (list of countries with mains voltage and frequency)
Open-circuit voltage
Phantom voltage
References
Footnotes
External links
Electrical voltage V, current I, resistivity R, impedance Z, wattage P
Electrical systems
Electromagnetic quantities | Voltage | Physics,Mathematics | 2,499 |
37,852,796 | https://en.wikipedia.org/wiki/Home%20Energy%20Assistance%20Target | The Home Energy Assistance Target (H.E.A.T.) program is the State of Utah’s program through which funds are distributed to the target population. This program is specifically administered by the state and various Associations of Governments (AOG). The Mountain land AOG provides H.E.A.T. assistance to persons in Utah, Wastach, and Summit Counties. MAG receives nearly $2.5 Million annually.
Recipients
Program recipients are on the rise. This may be illustrated in the following chart showing the increase in households served by the program in relation to the amount of LIHEAP funds allocated to the State of Utah. Some statistics of note for the State of Utah include:
SEALworks recorded that 1,619 households were shut off before coming in for HEAT assistance
HEAT program helped prevent 10,243 households, that had shut off notices, from being shut off
Almost $375,769 in regular HEAT Crisis assistance assisted 1,373 families in 2011
The program served 18,592 families with young children in 2011
The program assisted 10,875 elderly households to receive HEAT assistance in 2011
The program assisted 17,947 people who have disabilities in 2011
Coordination with outside programs
In addition to providing matching funds through the Leveraging Incentive Program, LIHEAP strives to coordinate efforts with private utility companies and non-profits where federal funding is not available. In the State of Utah, some of these other sources include Rocky Mountain Power’s Home Electric Lifeline and Lend-a-Hand Programs, Questar’s Energy Assistance Fund and REACH program, Catholic Community Services, American Red Cross, and Murray City Relief Program. H.E.A.T. funding applicants may be referred to these or other private assistance groups if there are not sufficient LIHEAP funds.
References
Sources
LIHEAP Clearinghouse (2012, October 3). Utahns to Get Reduced LIHEAP Benefit. Retrieved from LIHEAP Clearinghouse: https://web.archive.org/web/20160303235006/http://liheap.ncat.org/news/mar11/utah.htm
Hansell, D. A. (2012). FY 2012 Online Performance Appendix. Washington D.C: Department of Health and Human Services.
Henetz, P. (2011, October 7). Less Federal Help Expected for Low-Income Utahns’ Heating Bills. Retrieved from The Salt Lake Tribune: http://www.sltrib.com/sltrib/news/53201355-78/federal-income-low-utah.html.csp Perl, L. (2010).
The LIHEAP Formula: Legislative History and Current Law. Washington D.C.: Congressional Research Service. Retrieved from https://web.archive.org/web/20120417031043/http://www.neada.org/publications/2010-07-06.pdf
U.S. Department of Health and Human Services Administration Services, (2012, October 5). LIHEAP Fact Sheet. Retrieved from Office of Community Services an Office of the Administration for Children and Families: http://www.acf.hhs.gov/programs/ocs/resource/liheap-fact-sheet-0
U.S. Department of Health and Human Services Administration Services for Children & Families, (2012, October 2). Retrieved from LIHEAP Clearing House: https://web.archive.org/web/20121018090108/http://liheap.ncat.org/wwa.htm
Stone, C., Sherman, A., & Shaw, H. (2011, February 18). Administration's Rationale for Severe Cut in Low-Income Home Energy Assistance Is Weak. Retrieved September 19, 2012, from Budget and Policy Priorities: http://www.cbpp.org/cms/index.cfm?fa=view&id=3406
Wein, O. (2012, October 1). The Low Income Home Energy Assistance Program (LIHEAP). Retrieved from National Consumer Law Center: http://www.nclc.org/images/pdf/energy_utility_telecom/liheap/liheap-2page.pdf
Organizations based in Utah
Energy economics
Residential heating | Home Energy Assistance Target | Environmental_science | 906 |
310,883 | https://en.wikipedia.org/wiki/Distributive%20lattice | In mathematics, a distributive lattice is a lattice in which the operations of join and meet distribute over each other. The prototypical examples of such structures are collections of sets for which the lattice operations can be given by set union and intersection. Indeed, these lattices of sets describe the scenery completely: every distributive lattice is—up to isomorphism—given as such a lattice of sets.
Definition
As in the case of arbitrary lattices, one can choose to consider a distributive lattice L either as a structure of order theory or of universal algebra. Both views and their mutual correspondence are discussed in the article on lattices. In the present situation, the algebraic description appears to be more convenient.
A lattice (L,∨,∧) is distributive if the following additional identity holds for all x, y, and z in L:
x ∧ (y ∨ z) = (x ∧ y) ∨ (x ∧ z).
Viewing lattices as partially ordered sets, this says that the meet operation preserves non-empty finite joins. It is a basic fact of lattice theory that the above condition is equivalent to its dual:
x ∨ (y ∧ z) = (x ∨ y) ∧ (x ∨ z) for all x, y, and z in L.
In every lattice, if one defines the order relation p≤q as usual to mean p∧q=p, then the inequality x ∧ (y ∨ z) ≥ (x ∧ y) ∨ (x ∧ z) and its dual x ∨ (y ∧ z) ≤ (x ∨ y) ∧ (x ∨ z) are always true. A lattice is distributive if one of the converse inequalities holds, too.
More information on the relationship of this condition to other distributivity conditions of order theory can be found in the article Distributivity (order theory).
Morphisms
A morphism of distributive lattices is just a lattice homomorphism as given in the article on lattices, i.e. a function that is compatible with the two lattice operations. Because such a morphism of lattices preserves the lattice structure, it will consequently also preserve the distributivity (and thus be a morphism of distributive lattices).
Examples
Distributive lattices are ubiquitous but also rather specific structures. As already mentioned the main example for distributive lattices are lattices of sets, where join and meet are given by the usual set-theoretic operations. Further examples include:
The Lindenbaum algebra of most logics that support conjunction and disjunction is a distributive lattice, i.e. "and" distributes over "or" and vice versa.
Every Boolean algebra is a distributive lattice.
Every Heyting algebra is a distributive lattice. Especially this includes all locales and hence all open set lattices of topological spaces. Also note that Heyting algebras can be viewed as Lindenbaum algebras of intuitionistic logic, which makes them a special case of the first example.
Every totally ordered set is a distributive lattice with max as join and min as meet.
The natural numbers form a (conditionally complete) distributive lattice by taking the greatest common divisor as meet and the least common multiple as join. This lattice also has a least element, namely 1, which therefore serves as the identity element for joins.
Given a positive integer n, the set of all positive divisors of n forms a distributive lattice, again with the greatest common divisor as meet and the least common multiple as join. This is a Boolean algebra if and only if n is square-free.
A lattice-ordered vector space is a distributive lattice.
Young's lattice given by the inclusion ordering of Young diagrams representing integer partitions is a distributive lattice.
The points of a distributive polytope (a convex polytope closed under coordinatewise minimum and coordinatewise maximum operations), with these two operations as the join and meet operations of the lattice.
Early in the development of the lattice theory Charles S. Peirce believed that all lattices are distributive, that is, distributivity follows from the rest of the lattice axioms.
However, independence proofs were given by Schröder, Voigt,(de) Lüroth, Korselt, and Dedekind.
Characteristic properties
Various equivalent formulations to the above definition exist. For example, L is distributive if and only if the following holds for all elements x, y, z in L:
Similarly, L is distributive if and only if
and always imply
The simplest non-distributive lattices are M3, the "diamond lattice", and N5, the "pentagon lattice". A lattice is distributive if and only if none of its sublattices is isomorphic to M3 or N5; a sublattice is a subset that is closed under the meet and join operations of the original lattice. Note that this is not the same as being a subset that is a lattice under the original order (but possibly with different join and meet operations). Further characterizations derive from the representation theory in the next section.
An alternative way of stating the same fact is that every distributive lattice is a subdirect product of copies of the two-element chain, or that the only subdirectly irreducible member of the class of distributive lattices is the two-element chain. As a corollary, every Boolean lattice has this property as well.
Finally distributivity entails several other pleasant properties. For example, an element of a distributive lattice is meet-prime if and only if it is meet-irreducible, though the latter is in general a weaker property. By duality, the same is true for join-prime and join-irreducible elements. If a lattice is distributive, its covering relation forms a median graph.
Furthermore, every distributive lattice is also modular.
Representation theory
The introduction already hinted at the most important characterization for distributive lattices: a lattice is distributive if and only if it is isomorphic to a lattice of sets (closed under set union and intersection). (The latter structure is sometimes called a ring of sets in this context.) That set union and intersection are indeed distributive in the above sense is an elementary fact. The other direction is less trivial, in that it requires the representation theorems stated below. The important insight from this characterization is that the identities (equations) that hold in all distributive lattices are exactly the ones that hold in all lattices of sets in the above sense.
Birkhoff's representation theorem for distributive lattices states that every finite distributive lattice is isomorphic to the lattice of lower sets of the poset of its join-prime (equivalently: join-irreducible) elements. This establishes a bijection (up to isomorphism) between the class of all finite posets and the class of all finite distributive lattices. This bijection can be extended to a duality of categories between homomorphisms of finite distributive lattices and monotone functions of finite posets. Generalizing this result to infinite lattices, however, requires adding further structure.
Another early representation theorem is now known as Stone's representation theorem for distributive lattices (the name honors Marshall Harvey Stone, who first proved it). It characterizes distributive lattices as the lattices of compact open sets of certain topological spaces. This result can be viewed both as a generalization of Stone's famous representation theorem for Boolean algebras and as a specialization of the general setting of Stone duality.
A further important representation was established by Hilary Priestley in her representation theorem for distributive lattices. In this formulation, a distributive lattice is used to construct a topological space with an additional partial order on its points, yielding a (completely order-separated) ordered Stone space (or Priestley space). The original lattice is recovered as the collection of clopen lower sets of this space.
As a consequence of Stone's and Priestley's theorems, one easily sees that any distributive lattice is really isomorphic to a lattice of sets. However, the proofs of both statements require the Boolean prime ideal theorem, a weak form of the axiom of choice.
Free distributive lattices
The free distributive lattice over a set of generators G can be constructed much more easily than a general free lattice. The first observation is that, using the laws of distributivity, every term formed by the binary operations and on a set of generators can be transformed into the following equivalent normal form:
where are finite meets of elements of G. Moreover, since both meet and join are associative, commutative and idempotent, one can ignore duplicates and order, and represent a join of meets like the one above as a set of sets:
where the are finite subsets of G. However, it is still possible that two such terms denote the same element of the distributive lattice. This occurs when there are indices j and k such that is a subset of In this case the meet of will be below the meet of and hence one can safely remove the redundant set without changing the interpretation of the whole term. Consequently, a set of finite subsets of G will be called irredundant whenever all of its elements are mutually incomparable (with respect to the subset ordering); that is, when it forms an antichain of finite sets.
Now the free distributive lattice over a set of generators G is defined on the set of all finite irredundant sets of finite subsets of G. The join of two finite irredundant sets is obtained from their union by removing all redundant sets. Likewise the meet of two sets S and T is the irredundant version of The verification that this structure is a distributive lattice with the required universal property is routine.
The number of elements in free distributive lattices with n generators is given by the Dedekind numbers. These numbers grow rapidly, and are known only for n ≤ 9; they are
2, 3, 6, 20, 168, 7581, 7828354, 2414682040998, 56130437228687557907788, 286386577668298411128469151667598498812366 .
The numbers above count the number of elements in free distributive lattices in which the lattice operations are joins and meets of finite sets of elements, including the empty set. If empty joins and empty meets are disallowed, the resulting free distributive lattices have two fewer elements; their numbers of elements form the sequence
0, 1, 4, 18, 166, 7579, 7828352, 2414682040996, 56130437228687557907786, 286386577668298411128469151667598498812364 .
See also
Completely distributive lattice — a lattice in which infinite joins distribute over infinite meets
Duality theory for distributive lattices
Spectral space
References
Further reading
Lattice theory | Distributive lattice | Mathematics | 2,487 |
15,223,749 | https://en.wikipedia.org/wiki/ESS%20Technology | ESS Technology Incorporated is a private manufacturer of computer multimedia products, Audio DACs and ADCs based in Fremont, California with R&D centers in Kelowna, British Columbia, Canada and Beijing, China. It was founded by Forrest Mozer in 1983. Robert L. Blair is the CEO and President of the company.
Historically, ESS Technology was most famous for their line of their Audiodrive chips for audio cards. Now they are known for their line of Sabre DAC and ADC products.
History
ESS Technologies was founded in 1983 as Electronic Speech Systems, by Professor Forrest Mozer, a space physicist at the University of California, Berkeley and Todd Mozer, Forrest Mozer's son, and Joe Costello, the former manager of National Semiconductors Digitalker line of talking chips. Costello left soon after the formation and started Cadence Designs with his former boss from National. Fred Chan VLSI designer and software engineer, in Berkeley, California, joined in 1985, and took over running the company in 1986 when Todd Mozer left for graduate school.
The company was created at least partially as a way to market Mozer's speech synthesis system (described in US patents 4,214,125, 4,433,434 and 4,435,831) after his (3-year, summer 1978 to summer 1981, extended) contract with National Semiconductor expired in 1983 or so.
Electronic Speech Systems produced synthetic speech for, among other things, home computer systems like the Commodore 64. Within the hardware limitations of that time, ESS used Mozer's technology, in software, to produce realistic-sounding voices that often became the boilerplate for the respective games. Two popular sound bites from the Commodore 64 were "He slimed me!!" from Ghostbusters and Elvin Atombender's "Another visitor. Stay a while—stay forever!" in the original Impossible Mission.
At some point, the company moved from Berkeley to Fremont, California. Around that time, the company was renamed to ESS Technology.
Later, in 1994, Forrest Mozer's son Todd Mozer, an ESS employee, branched off and started his own company called Sensory Circuits Inc, later Sensory, Inc. to market speech recognition technology.
In the mid-1990s, ESS started working on making PC audio, and later, video chips, and created the Audiodrive line, used in hundreds of different products. Audiodrive chips were at least nominally Creative Sound Blaster Pro compatible. Many Audiodrive chips also featured in-house developed, OPL3-compatible FM synthesizers (branded ESFM Synthesizers). These synthesizers were often reasonably faithful to the Yamaha OPL3 chip, which was an important feature for the time as some competing solutions, including Creative's own CQM synthesis featured in later ISA Sound Blaster compatibles, offered sub-par FM sound quality. Some PCI-interface Audiodrives (namely the ES1938 Solo-1) also provided legacy DOS compatibility through Distributed DMA and the SB-Link interface.
In 2001 ESS acquired a small Kelowna design company (SAS) run by Martin Mallinson and continues R&D operations in Kelowna. The Kelowna R&D Center developed the Sabre range of DAC and ADC products that are used in many audio systems and cell phones.
Founders
Forrest Mozer continues his research work at the University of California, these days as Associate Director of Space Sciences. He was awarded EGU Hannes Alfven Medallist 2004 for his work in electrical field measurement and space plasma and also was involved in building the microphone to record sounds from the Mars Lander. He is a member of the board of directors of Sensory, Inc.
Fred Chan held a number of positions at ESS, and was CEO of Vialta, an internet offshoot of ESS, until his stepping down on July 18, 2007, to pursue philanthropic interests.
Professor Mozer's Patented Technology
Professor Mozer first became interested in speech technology when a blind student in his class in 1970 asked whether he could help design a talking calculator. Mozer spent 5 years working on it, and his speech technology first appeared in the Telesensory Systems "Speech+" talking calculator, in a chip called the "CRC Chip", more commonly known as s14001a, the first self-contained speech synthesizer chip. This chip was also used in a few arcade games, notably Atari's Wolf Pack, and Stern Electronics' Berzerk and Frenzy, and in several of Stern's pinball machines.
After a three-year exclusive deal with Telesensory Systems from 1975 to 1978, Forrest Mozer sold a 3-year license to National Semiconductor, and they created another chip using Mozer synthesis, the MM54101 "Digitalker". At first, even then, all words were encoded by hand by Mozer in his basement, but in the third or fourth year of the license, National came up with a software encoder for it. After the exclusive license expired (National seemed to have a "non-exclusive" license for a year or so), Mozer licensed the technology to ESS. After Mozer's son Todd split off and created Sensory Circuits Inc., the technology was licensed there.
According to the Sensory Inc. history pages and old datasheets, they offered three types of compression:
MX (this compression is nearly identical to that used on the Digitalker, with some minor coding changes and possibly some RLE. It's apparently used on some alarm systems and on the Vtech talking baseball/football cards)
CX
SX
and a few other PCM/LPC based systems.
Although Sensory bought up the Texas Instruments' speech products, their main focus has been on speech recognition, and not synthesis.
Professor Mozer's technique not only produced very realistic sounding speech, it also required very little on-chip (later, in software) RAM, a sparse and expensive commodity at that time. The advanced compression algorithm (patented, an early form of psychoacoustic compression using similar spectra of ADPCM-encoded waves) reduced the memory footprint of speech about a hundredfold, so one second of speech would require 90 to 625 bytes. With ESS-speech, samples that would normally require almost all of the 64 kilobyte memory of the Commodore 64 (if encoded in PCM) were so small, that the entire game fit into the RAM along with speech, without requiring additional loads from disk.
Games featuring ESS-speech
Fisher Price Jungle Book Reading (Apple II, 19??)
Impossible Mission (C64, 1984)
Ghostbusters (C64, 1984)
Cave of the Word Wizard (C64, 1984)
Talking Teacher (C64, 1985)
Kennedy Approach (C64, 1985)
Desert Fox (C64, 1985)
Beach Head II (C64, 1985)
221b Baker Street (C64, 1986)
Solo Flight (C64, 1986)
Big Bird's Hide and Speak (NES, 1990)
Mickey's Jigsaw Puzzles (DOS, 1991)
Products
ES1868 AudioDrive
ES9218P SABRE high fidelity system-on-chip; 32-bit stereo mobile digital-to-analog converter with 2 Volt headphone amplifier.
Present day
Most recently, ESS SABRE DACs are used in the LG V10 smartphone, with a quad DAC configuration present in the V10's successor LG V20. A slightly upgraded version of the same DAC in the V20, the SABRE ES9218P, is used in the V30 as well as the V40 ThinQ. The ESS9038Pro is their flagship and competes against Japanese AKM (Asahi Kasei Microdevices) AK4499EXEQ and American Cirrus Logic CS43131 for a share of the market. ESS and AKM dominate the desktop audiophile devices including external DACs and integrated all in one DAC/Amp devices. Meanwhile Cirrus Logic dominates the portable device market, Apple Inc is its number one customer accounting for approximately 83% of its chip sales.
The luxury Sennheiser HE 1 electrostatic headphone utilizes 8 internal DACs of the SABRE ES9018.
See also
Covox Speech Thing
References
External links
Mediaplayer with most game speech samples from ESS
Speech Box - Commodore Zone about ESS
Commodore Zone about Sensory Inc.
A 1985 article from Commodore User about speech in computer games, with some 2006 additions
Technology companies established in 1984
Computer companies established in 1984
Companies based in Berkeley, California
Companies based in Fremont, California
Technology companies based in the San Francisco Bay Area
Computer companies of the United States
Computer hardware companies | ESS Technology | Technology | 1,793 |
77,418,687 | https://en.wikipedia.org/wiki/NGC%203430 | NGC 3430 is a barred spiral galaxy in the constellation of Leo Minor. Its velocity with respect to the cosmic microwave background is 1,869 ± 20km/s, which corresponds to a Hubble distance of . In addition, 22 non-redshift measurements give a distance of . It was discovered by German-British astronomer William Herschel on 7 December 1785.
NGC 3430 is classified as a well-known example of an SAc spiral galaxy with no central bar structure but has spiral arms found open and clear-defined. Moreover, it is also a Wolf-Rayet galaxy, with star-forming regions and forms a pair with NGC 3424, a nearby starburst galaxy. According to a 1997 study presented by researchers, these galaxies are clearly showing signs of tidal interaction.
NGC 3396 Group
NGC 3430 is a member of the NGC 3396 group (also known as LGG 218). This group that includes at least 11 galaxies: NGC 3381, NGC 3395, NGC 3396, NGC 3424, NGC 3430, NGC 3442, IC 2604, UGC 5898, PGC 32631, UGC 5934, and UGC 5990.
Supernovae
Two supernovae have been observed in NGC3936:
SN2004ez (typeII, mag.17.3) was discovered by Kōichi Itagaki on 15 October 2004.
PSNJ10520833+3256394 (typeIIb, mag.17.8) was discovered by Kōichi Itagaki on 27 August 2015.
See also
List of NGC objects (3001–4000)
References
External links
3430
05982
032614
10494+3312
17851207
Discoveries by William Herschel
+06-24-026
Barred spiral galaxies
Leo Minor | NGC 3430 | Astronomy | 376 |
1,695,658 | https://en.wikipedia.org/wiki/Garmin%20Forerunner | The Garmin Forerunner series is a selection of sports watches produced by Garmin. Most models use the Global Positioning System (GPS), and are targeted at road runners and triathletes. Forerunner series watches are designed to measure distance, speed, heart rate (optional), time, altitude, steps, and pace.
Models
The Forerunner series consists of models 101, 201, 301, 205, 305, 50, 405, 60, 405CX, 310XT, 110, 210, 410, 610, 910XT, 70, 10, 220, 620, 15, 920XT, 225, 25, 230, 235, 630, 735XT, 35, 935, 30, 645, 645 Music, 45, 45S, 245, 245 Music, 945, 745, 55, 945 LTE, 255, 255 Music, 955, 955 Solar, 265, 965, 158, 165 (listed in chronological order by release date). All models of the Forerunner series except the 101 include a way to upload training data to a personal computer and training software.
Garmin registered the name "Forerunner" with the United States Patent and Trademark Office in August 2001 but released the first watches—the 101, 201, and 301—in 2003.
In 2006, the 205 and 305 launched. These models are smaller than the first generation and feature a more sensitive SiRFstarIII GPS receiver chip.
In late 2007, the Forerunner 50 was introduced. As opposed to GPS, this model paired with a foot pod to measure displacement. The Forerunner 50 came with a USB stick that allowed training data to be transferred wirelessly to one's pc. This feature has since become a staple of Garmin's more full-featured sport watches.
The Forerunner 405 was introduced in 2008 and is significantly smaller than its predecessors, only slightly outsizing a typical wristwatch. The 405 also featured improved satellite discovery and connection.
In 2009, Garmin produced three new models: the Forerunner 60 (an evolution of the Forerunner 50), the Forerunner 405CX (405 chassis), and the Forerunner 310XT (an evolution of the 305 chassis). New features in these models included additional battery life and vibration alerts on the 310XT and advanced calorie consumption modelling on all watches. The new calorie consumption modelling in these devices was the result of Garmin's first collaboration with Finnish physiological analytics firm First beat. The 310XT was also the first watch of the Forerunner series to be waterproof, thus allowing its use for swimming and on all legs of a Triathlon, also thanks to extended battery life. In 2010 a firmware update added vastly improved open-water swimming metrics.
In 2010, the Forerunner 110, 210 and 410 were introduced. The releases included the addition of a touch-sensitive bezel on the 410, presumably, although heavily debated, allowing for easier scrolling and selection of functions. It was touted as providing "unmatched reliability in sweaty, rainy conditions."
The Forerunner 610 was released in the spring of 2011. It features a touch-sensitive screen as well as vibration alerts.
In 2012 the Forerunner 910XT was introduced, which is a development of the 310XT. This version was originally supposed to be released in Q4 of 2011, but the November date had slipped and it was eventually released in Q1 of 2012. New features introduced in this model are the inclusion of the Sifter iv chipset, a barometric altimeter, and improved swimming metrics using an accelerometer in the watch. This allowed it to automatically count pool lengths and to recognize swimming styles.
A further addition to the series was the Forerunner 10, a simple watch offering just GPS tracking of activities and run metrics like distance, pace and calories burned.
At the end of 2013 the Forerunner 220 and 620 were introduced, with colour screens, Bluetooth Low Energy (BLE; allowing connections to some smartphones), and, for the 620 only, a touchscreen, Wi-Fi (allowing automatic activity download) and enhanced "running dynamics" given by an updated Heart rate monitor. These watches also abandon syncing via the ANT+ protocol in favour of wired (USB) and Wi-Fi (620 only) data transfers. They are also fully waterproof, but do not include any kind of swimming mode.
In 2014, the Forerunner 15 and 920XT were introduced. The 15 is a development of the 10, adding activity tracking, increased battery life, footpad and heart rate monitor capability. The 920XT is the successor of the 910XT, featuring all the capabilities of it (except ANT+ scale and fitness equipment capability) and adding features found in the 620 such as a colour screen, Wi-Fi data transfers and running dynamics. Additionally, battery life over the 910XT was improved, daily activity tracking, GLONASS support and a swim drill mode added, and the 920XT is the first Garmin watch extensible with custom apps built using the Garmin Connect IQ software development kit.
Announced in May 2015, the Forerunner 225 is the first Garmin watch with an integrated optical heart rate monitor.
Announced in May 2016, the Forerunner 735XT is a triathlon-ready Garmin watch with an integrated optical heart rate monitor.
In April 2017, Garmin announced the Forerunner 935, billing it as a watch for running and triathlons with features similar to the Fenix 5. The watch boasts 24/7 wrist-based heart rate monitoring and new advanced training features.
On March 12, 2018, Garmin released the Forerunner 645 and 645 Music marketed as a high-end running watch. The watch adds Garmin Pay, an NFC-enabled touchless pay system and the 645 Music is Garmin's first watch with onboard music storage (4 GB).
The Forerunner 45/45S, released on April 30, 2019, is an entry-level running watch. The 45S has a smaller bezel (39mm) than the 45 (42mm) - there are no other differences. It has a 3rd generation optical heart rate monitor which features stress detection and Body Battery energy, along with earlier-generation OHR metrics. Bluetooth-connected features include audio prompts, Live Track, and smart notifications. The activity profiles include outdoor running, treadmill, walk, bike, and cardio, with the ability to configure more through Garmin Connect. The Forerunner 45 has built-in incident detection and assistance, which notifies a predetermined contact if it detects a crash or fall and provides a live tracking link for the watch's location.
The Forerunner 245/245 Music, released on April 30, 2019, are mid-range running watches. The 245 has all of the same capabilities as the 245 Music, though the 245 Music allows you to store and play up to 500 songs directly on the watch or play music through music streaming services, such as Spotify or Deezer, through wireless Bluetooth earphones. The 245 has Garmin Elevate with a 3rd generation optical heart rate monitor which features Pulse Ox, stress detection, Body Battery energy, along with earlier-generation OHR metrics. Also new for the Forerunner is a detailed Activity summary screen, improved Race Predictor and Training Status.
The Forerunner 945, released on April 30, 2019, is a triathlon-focused feature-rich watch. The 945 allows you to store and play up to 1000 songs directly on the watch or play music through music streaming services, such as Spotify or Deezer, through wireless Bluetooth earphones. The 945 has all of the capabilities of its 935 predecessor and all of the features of the Forerunner 245. Other new features of the 945 are heat and altitude acclimation, training load balance, mapping with Trendline popularity routing, respiration rate, Around me mode, Climber future elevation plot, cartography support and topographical maps, XERO location, and for the golfer, the 945 is preloaded with 41,000 courses.
The Forerunner 955, released April 30, 2022, is a superset of the Forerunner 945 and includes a touch screen. To extend battery life, the Forerunner 955 Solar has a solar charging ring in the display. Charging for both 955 models is through the proprietary Garmin charging port and a USB-A connector.
In March 2023, Garmin announced the Forerunner 265/265S and Forerunner 965. Both models are very similar to their predecessors, but feature AMOLED displays for the first time.
Garmin has released the Garmin Forerunner 158 which is only available in China.
Features
GPS functionality
The Forerunner can be used to record historical data by completing a workout and then uploading the data to a computer to create a log of previous exercise activities for analysis.
Additionally, the Forerunner can be used to navigate during a workout. Users can "mark" their current location and then edit this entry's name and coordinates, which enables navigation to those new coordinates. The watch uses the hh.mm.mm (hours, minutes, and minute decimals) coordinate format. The 310XT can display additional formats; it also has a screen to display current coordinates in real-time.
Computer interface
The user can download a previously-travelled course/route to the Forerunner using Garmin's Communicator software together with the ANT+ technology, and then follow this course/route to "race" against this historical course/route. Until recently this download was possible via the tethered USB connection on the older 205 & 305 models. However, the current version of the software has eliminated this option, requiring the user to acquire a newer model with a wireless connection in order to use this feature.
The user can also make new courses or routes, which can be downloaded to the watch and then followed. This is a convenient way to go on a cross-country bike ride while navigating with the Forerunner. Note: navigating with a course is better than navigating with a route, because a Garmin course can store more points than a Garmin route.
Additionally, a user can create downloadable points of interest (POIs) by creating a custom map with Google Maps. POIs can be transferred to the 205 or 305 but not to the 405 or 310XT.
Release history
Timeline
More details: List of Garmin products
Feature comparison
Key: Current Model
See also
Garmin Fenix
References
External links
Garmin Official Site
Sport of athletics equipment
Garmin
Global Positioning System | Garmin Forerunner | Technology,Engineering | 2,151 |
14,817,321 | https://en.wikipedia.org/wiki/ANXA8L2 | Annexin A8-like protein 2 is a protein that in humans is encoded by the ANXA8L2 gene.
This gene encodes a member of the annexin family of evolutionarily conserved Ca2+ and phospholipid binding proteins. The encoded protein may function as an anticoagulant that indirectly inhibits the thromboplastin-specific complex. Overexpression of this gene has been associated with acute myelocytic leukemia. A highly similar duplicated copy of this gene is found in close proximity on the long arm of chromosome 10.
References
External links
Further reading | ANXA8L2 | Chemistry | 127 |
2,606,275 | https://en.wikipedia.org/wiki/Medical%20gas%20supply | Medical gas supply systems in hospitals and other healthcare facilities are utilized to supply specialized gases and gas mixtures to various parts of the facility. Products handled by such systems typically include:
Oxygen
Medical air
Nitrous oxide
Nitrogen
Carbon dioxide
Medical vacuum
Waste anaesthetic gas disposal (US) or anaesthetic gas scavenging system (ISO)
Source equipment systems are generally required to be monitored by alarm systems at the point of supply for abnormal (high or low) gas pressure in areas such as general ward, operating theatres, intensive care units, recovery rooms, or major treatment rooms. Equipment is connected to the medical gas pipeline system via station outlets (US) or terminal units (ISO).
Medical gas systems are commonly color coded to identify their contents, but as coding systems and requirements (such as those for bottled gas) vary by jurisdiction, the text or labeling is the most reliable guide to the contents. Emergency shut-off valves, or zone valves, are often installed in order to stop gas flowing to an area in the event of fire or substantial leak, as well as for service. Valves may be positioned at the entrance to departments, with access provided via emergency pull-out windows.
Oxygen
Oxygen may be used for patients requiring supplemental oxygen via mask. Usually accomplished by a large storage system of liquid oxygen at the hospital which is evaporated into a concentrated oxygen supply, pressures are usually around , or in the UK and Europe, . This arrangement is described as a vacuum insulated evaporator or bulk tank. In small medical centers with a low patient capacity, oxygen is usually supplied by a manifold of multiple high-pressure cylinders. In areas where a bulk system or high-pressure cylinder manifold is not suitable, oxygen may be supplied by an oxygen concentrator. However, on site production of oxygen is still a relatively new technology.
Medical air
Medical air is compressed air supplied by a special air compressor, through a dryer (in order to maintain correct dew point levels), and distributed to patient care areas by half hard BS:EN 13348 copper pipe and also use isolation ball valve for operating the services of compressed air 4 bar. It is also called medical air 4 bar. In smaller facilities, medical air may also be supplied via high-pressure cylinders. Pressures are maintained around . If not used correctly it can be harmful to humans.
Nitrous oxide
Nitrous oxide is supplied to various surgical suites for its anaesthetic functions during preoperative procedures. It is delivered to the hospital in high-pressure cylinders and supplied through the Medical Gas system. Some bulk systems exist, but are no longer installed due to environmental concerns and overall reduced consumption of nitrous oxide. System pressures are around , UK.
Nitrogen
Nitrogen is typically used to power pneumatic surgical equipment during various procedures, and is supplied by high-pressure cylinders. Pressures range around to various locations.
Instrument air/surgical air
Like nitrogen, instrument air is used to power surgical equipment. However, it is generated on site by an air compressor (similar to a medical air compressor) rather than high-pressure cylinders. Early air compressors could not offer the purity required to drive surgical equipment. However, this has changed and instrument air is becoming a popular alternative to nitrogen. As with nitrogen, pressures range around . UK systems are supplied at to the local area and regulated down to at point of use.
Carbon dioxide
This gas is typically used pure for insufflation during surgery, but can also be used in its liquid form for cryotherapy or local analgesia. Mixed with other gases, it can be used for sterilisation of equipment, anaesthesia, and stimulation of the respiratory system.
A mixture of 5% carbon dioxide in oxygen is called carbogen and is used in the investigation and treatment of various respiratory conditions, such as to stimulate breathing after a period of apnoea, and managing chronic respiratory obstruction.
Medical vacuum
Medical vacuum in a hospital supports suction equipment and evacuation procedures, supplied by vacuum pump systems exhausting to the atmosphere. Vacuum will fluctuate across the pipeline, but is generally maintained around , UK.
Waste anaesthetic gas disposal/anaesthetic gas scavenging system
Waste anaesthetic gas disposal, or anaesthetic gas scavenging system, is used in hospital anaesthesia evacuation procedures. Although it is similar to a medical vacuum system, some building codes require anaesthetic gases to be scavenged separately. Scavenging systems do not need to be as powerful as medical vacuum systems, and can be maintained around .
Medical gas mixtures
There are many gas mixtures used for clinical and medical applications. They are often used for patient diagnostics such as lung function testing or blood gas analysis. Test gases are also used to calibrate and maintain medical devices used for the delivery of anaesthetic gases. In laboratories, culture growth applications include controlled aerobic or anaerobic incubator atmospheres for biological cell culture or tissue growth. Controlled aerobic conditions are created using mixtures rich in oxygen and anaerobic conditions are created using mixtures rich in hydrogen or carbon dioxide. Supply pressure is .
Two common medical gas mixtures are entonox and heliox.
References
External links
HTM02-01 Medical Gas Pipeline Systems Part A: Design, installation, validation and verification, British Compressed Gases Association website: Department of Health (United Kingdom)
HTM02-01 Medical Gas Pipeline Systems Part B: Operational Management British Compressed Gases Association website: Department of Health (United Kingdom)
Medical equipment
Industrial gases | Medical gas supply | Chemistry,Biology | 1,122 |
403,043 | https://en.wikipedia.org/wiki/Cum%20shot | A cum shot is the depiction of human ejaculation, especially onto another person. The term is usually applied to depictions occurring in pornographic films, photographs, and magazines. Unlike ejaculation in non-pornographic sex, cum shots typically involve ejaculation outside the receiver's body, allowing the viewer to see the ejaculation in progress. Facial cum shots (or "facials") are regularly portrayed in pornographic films and videos, often as a way to close a scene. Cum shots may also depict ejaculation onto another performer's body, such as on the genitals, buttocks, chest or tongue.
The term is typically used by the cinematographer within the narrative framework of a pornographic film, and, since the 1970s, it has become a leitmotif of the hardcore genre. Two exceptions are softcore pornography, in which penetration is not explicitly shown, and "couples erotica", which may involve penetration but is typically filmed in a more discreet manner intended to be romantic or educational rather than graphic. Softcore pornography that does not contain ejaculation sequences is produced both to respond to a demand by some consumers for less-explicit pornographic material and to comply with government regulations or cable company rules that may disallow depictions of ejaculation. Cum shots typically do not appear in "girl-girl" scenes (female ejaculation scenes exist, but are relatively uncommon); orgasm is instead implied by utterances, cinematic conventions, or body movement.
Cum shots have become the object of fetish genres like bukkake, in which the cum shot replaces the sex act completely.
Terminology
A cum shot may also be called a cumshot, come shot, cum blast, pop shot or money shot.
Originally, in general film-making usage the term money shot was a reference to the scene that cost the most money to produce; in addition, the inclusion of this expensive special effect sequence is being counted on to become a selling point for the film. For example, in an action thriller, an expensive special effects sequence of an explosion might be called the "money shot" of the film. The use of money shot to denote the ejaculation scene in pornographic films is attributed to producers paying the male actors extra for it. The meaning of the term money shot has sometimes been borrowed back from pornography by the film and TV industry with a meaning closer to that used in pornographic films. For example, in TV talk shows, the term, borrowed from pornography, denotes a highly emotional scene, expressed in visible bodily terms.
Origin and features
Although earlier pornographic films occasionally contained footage of ejaculation, it was not until the advent of hard-core pornography in the 1970s that the stereotypical cum shot scene became a standard feature—displaying ejaculation with maximum visibility. The 1972 film Behind the Green Door featured a seven-minute-long sequence described by Linda Williams, professor of film studies, as "optically printed, psychedelically colored doublings of the ejaculating penis". Steven Ziplow's The Film Maker's Guide to Pornography (1977) states:
Cum shot scenes may involve the female actor calling for the shot to be directed at some specific part of her body. Cultural analysis researcher Murat Aydemir considers this one of the three quintessential aspects of the cum shot scene, alongside the emphasis on visible ejaculation and the timing of the cum shot, which usually concludes a hard-core scene.
As a possible alternative explanation for the rise of the cum shot in hardcore pornography, Joseph Slade, professor at Ohio University and author of Pornography and sexual representation: a reference guide notes that pornography actresses in the 1960s and 1970s did not trust birth control methods, and that more than one actress of the period told him that ejaculation inside her body was deemed inconsiderate if not rude.
Health risks
Transmission of disease
Any sexual activity that involves contact with the bodily fluids of another person contains the risk of transmission of sexually transmitted diseases. Semen is in itself generally harmless on the skin or if swallowed. However, semen can be the vehicle for many sexually transmitted infections, such as HIV and hepatitis. The California Occupational Safety and Health Administration categorizes semen as "other potentially infectious material" or OPIM.
Aside from other sexual activity that may have occurred prior to performing a facial, the risks incurred by the giving and receiving partner are drastically different. For the ejaculating partner, there is almost no risk of contracting an STD. For the receiving partner, the risk is higher. Since potentially infected semen could come into contact with broken skin or sensitive mucous membranes (e.g., eyes, lips, mouth), there is a risk of contracting an infectious disease.
Allergic reactions
In rare cases, people have been known to experience allergic reactions to seminal fluids, known as human seminal plasma hypersensitivity. Symptoms can be either localized or systemic, and may include itching, redness, swelling, or blisters within 30 minutes of contact. They may also include hives and even difficulty breathing.
Options for prevention of semen allergy include avoiding exposure to seminal fluid by use of condoms and attempting desensitization. Treatment options include diphenhydramine and/or an injection of epinephrine.
Criticisms and responses
One critic of "cum shot" scenes in heterosexual pornography was the US porn star–turned–writer, director and producer Candida Royalle. She produced pornography films aimed at women and their partners that avoid the "misogynous predictability" and depiction of sex in "...as grotesque and graphic [a way] as possible." Royalle also criticizes the male-centredness of the typical pornography film, in which scenes end when the male actor ejaculates.
Women's activist Beatrice Faust argued, "since ejaculating into blank space is not much fun, ejaculating over a person who responds with enjoyment sustains a lighthearted mood as well as a degree of realism. This occurs in both homosexual and pornography so that ejaculation cannot be interpreted as an expression of contempt for women only."
She goes on to say "Logically, if sex is natural and wholesome and semen is as healthy as sweat, there is no reason to interpret ejaculation as a hostile gesture."
Sexologist Peter Sándor Gardos argues that his research suggests that "... the men who get most turned on by watching cum shots are the ones who have positive attitudes toward women" (at the annual meeting of the Society for the Scientific Study of Sex in 1992). Later, at the World Pornography Conference in 1998, he reported a similar conclusion, namely that "no pornographic image is interpretable outside of its historical and social context. Harm or degradation does not reside in the image itself."
Cindy Patton, activist and scholar on human sexuality, argues that, in western culture, male sexual fulfillment is synonymous with orgasm and that the male orgasm is an essential punctuation of the sexual narrative. No orgasm, no sexual pleasure. No cum shot, no narrative closure. The cum shot is the period at the end of the sentence.
In her essay "Visualizing Safe Sex: When Pedagogy and Pornography Collide", Patton reached the conclusion that critics have devoted too little space to discovering the meaning that viewers attach to specific acts such as cum shots.
See also
Notes
Pornography terminology
Ejaculation
Sexual acts | Cum shot | Biology | 1,529 |
25,116,347 | https://en.wikipedia.org/wiki/Register%20of%20data%20controllers | The register of data controllers was a United Kingdom database under the control of the UK Information Commissioner's Office (ICO) mandated by section 19 of the Data Protection Act 1998.
The register of fee payers is the name of an equivalent register established under the Data Protection Act 2018, which implements the European Union's General Data Protection Regulation (GDPR).
Registration under either Act carries a fee, the proceeds of which fund the costs of the ICO. Any entry may be inspected by the public at any time at no cost to the enquirer.
Data Protection Act 1998
Under the 1998 Act, the name of the data controller was recorded with the purpose(s) for the processing of the data processed by that controller within the meaning of the Act.
The 1998 Act established a distinction between data controllers and data processors, to whom distinct legal and governance obligations applied: data controllers determined the purposes for which personal data was held or processed, whereas data process data on behalf of another data controller.
A data controller may, under some circumstances, be exempt from registration (previously termed notification). When not exempt, failure to notify the Information Commissioner's Office formally before the start of processing data was a strict liability offence for which a prosecution may be brought by the Information Commissioner's Office in the criminal court of the UK. Failure to notify was a criminal offence unless exempt. Exemption from registration does not exempt a data controller from compliance with The Act.
Amendments to a data controller's notification could be made at any time, and must have been made before the start of a new processing purpose.
Data Protection Act 2018
Under the 2018 Act, the register is called the register of fee payers, and the purposes for processing are nor supplied, though other trading names and the name of a Data Protection Officer may be given. The distinction between data controllers and data processors remains in place. the ICO reports that there are over one million registered fee payers.
The enforcement of the Act by the Information Commissioner's Office is supported by a data protection charge on UK data controllers under the Data Protection (Charges and Information) Regulations 2018. Exemptions from the charge were left broadly the same as for 1998 Act: largely some businesses and non-profits internal core purposes (staff or members, marketing and accounting), household affairs, some public purposes, and non-automated processing. Under the 2018 Act, the enforcement regime for registration changed from criminal to civil monetary penalties.
See also
General Data Protection Regulation#United Kingdom implementation
References
External links
Register of fee payers, at which any entry may be inspected at no charge.
Information privacy
Government databases in the United Kingdom
Law of the United Kingdom | Register of data controllers | Engineering | 540 |
24,684,701 | https://en.wikipedia.org/wiki/Outline%20of%20robotics | The following outline is provided as an overview of and topical guide to robotics:
Robotics is a branch of mechanical engineering, electrical engineering and computer science that deals with the design, construction, operation, and application of robots, as well as computer systems for their control, sensory feedback, and information processing. These technologies deal with automated machines that can take the place of humans in dangerous environments or manufacturing processes, or resemble humans in appearance, behaviour, and or cognition. Many of today's robots are inspired by nature contributing to the field of bio-inspired robotics.
The word "robot" was introduced to the public by Czech writer Karel Čapek in his play R.U.R. (Rossum's Universal Robots), published in 1920. The term "robotics" was coined by Isaac Asimov in his 1941 science fiction short-story "Liar!"
Nature of robotics
Robotics can be described as:
An applied science – scientific knowledge transferred into a physical environment.
A branch of computer science –
A branch of electrical engineering –
A branch of mechanical engineering –
Research and development –
A branch of technology –
Branches of robotics
Adaptive control – control method used by a controller which must adapt to a controlled system with parameters which vary, or are initially uncertain. For example, as an aircraft flies, its mass will slowly decrease as a result of fuel consumption; a control law is needed that adapts itself to such changing conditions.
Aerial robotics – development of unmanned aerial vehicles (UAVs), commonly known as drones, aircraft without a human pilot aboard. Their flight is controlled either autonomously by onboard computers or by the remote control of a pilot on the ground or in another vehicle.
Android science – interdisciplinary framework for studying human interaction and cognition based on the premise that a very humanlike robot (that is, an android) can elicit human-directed social responses in human beings.
Anthrobotics – science of developing and studying robots that are either entirely or in some way human-like.
Artificial intelligence – the intelligence of machines and the branch of computer science that aims to create it.
Artificial neural networks – a mathematical model inspired by biological neural networks.
Autonomous car – an autonomous vehicle capable of fulfilling the human transportation capabilities of a traditional car
Autonomous research robotics –
Bayesian network –
BEAM robotics – a style of robotics that primarily uses simple analogue circuits instead of a microprocessor in order to produce an unusually simple design (in comparison to traditional mobile robots) that trades flexibility for robustness and efficiency in performing the task for which it was designed.
Behavior-based robotics – the branch of robotics that incorporates modular or behavior based AI (BBAI).
Bio-inspired robotics – making robots that are inspired by biological systems. Biomimicry and bio-inspired design are sometimes confused. Biomimicry is copying the nature while bio-inspired design is learning from nature and making a mechanism that is simpler and more effective than the system observed in nature.
Biomimetic – see Bionics.
Biomorphic robotics – a sub-discipline of robotics focused upon emulating the mechanics, sensor systems, computing structures and methodologies used by animals.
Bionics – also known as biomimetics, biognosis, biomimicry, or bionical creativity engineering is the application of biological methods and systems found in nature to the study and design of engineering systems and modern technology.
Biorobotics – a study of how to make robots that emulate or simulate living biological organisms mechanically or even chemically.
Cloud robotics – is a field of robotics that attempts to invoke cloud technologies such as cloud computing, cloud storage, and other Internet technologies centered around the benefits of converged infrastructure and shared services for robotics.
Cognitive robotics – views animal cognition as a starting point for the development of robotic information processing, as opposed to more traditional Artificial Intelligence techniques.
Clustering –
Computational neuroscience – study of brain function in terms of the information processing properties of the structures that make up the nervous system.
Robot control – a study of controlling robots
Robotics conventions –
Data mining Techniques –
Degrees of freedom – in mechanics, the degree of freedom (DOF) of a mechanical system is the number of independent parameters that define its configuration. It is the number of parameters that determine the state of a physical system and is important to the analysis of systems of bodies in mechanical engineering, aeronautical engineering, robotics, and structural engineering.
Developmental robotics – a methodology that uses metaphors from neural development and developmental psychology to develop the mind for autonomous robots
Digital control – a branch of control theory that uses digital computers to act as system controllers.
Digital image processing – the use of computer algorithms to perform image processing on digital images.
Dimensionality reduction – the process of reducing the number of random variables under consideration, and can be divided into feature selection and feature extraction.
Distributed robotics –
Electronic stability control – is a computerized technology that improves the safety of a vehicle's stability by detecting and reducing loss of traction (skidding).
Evolutionary computation –
Evolutionary robotics – a methodology that uses evolutionary computation to develop controllers for autonomous robots
Extended Kalman filter –
Flexible Distribution functions –
Feedback control and regulation –
Human–computer interaction – a study, planning and design of the interaction between people (users) and computers
Human robot interaction – a study of interactions between humans and robots
Intelligent vehicle technologies – comprise electronic, electromechanical, and electromagnetic devices - usually silicon micromachined components operating in conjunction with computer controlled devices and radio transceivers to provide precision repeatability functions (such as in robotics artificial intelligence systems) emergency warning validation performance reconstruction.
Computer vision –
Machine vision –
Kinematics – study of motion, as applied to robots. This includes both the design of linkages to perform motion, their power, control and stability; also their planning, such as choosing a sequence of movements to achieve a broader task.
Laboratory robotics – the act of using robots in biology or chemistry labs
Robot learning – learning to perform tasks such as obstacle avoidance, control and various other motion-related tasks
Direct manipulation interface – In computer science, direct manipulation is a human–computer interaction style which involves continuous representation of objects of interest and rapid, reversible, and incremental actions and feedback. The intention is to allow a user to directly manipulate objects presented to them, using actions that correspond at least loosely to the physical world.
Manifold learning –
Microrobotics – a field of miniature robotics, in particular mobile robots with characteristic dimensions less than 1 mm
Motion planning – (a.k.a., the "navigation problem", the "piano mover's problem") is a term used in robotics for the process of detailing a task into discrete motions.
Motor control – information processing related activities carried out by the central nervous system that organize the musculoskeletal system to create coordinated movements and skilled actions.
Nanorobotics – the emerging technology field creating machines or robots whose components are at or close to the scale of a nanometer (10−9 meters).
Passive dynamics – refers to the dynamical behavior of actuators, robots, or organisms when not drawing energy from a supply (e.g., batteries, fuel, ATP).
Programming by Demonstration – an End-user development technique for teaching a computer or a robot new behaviors by demonstrating the task to transfer directly instead of programming it through machine commands.
Quantum robotics – a subfield of robotics that deals with using quantum computers to run robotics algorithms more quickly than digital computers can.
Rapid prototyping – automatic construction of physical objects via additive manufacturing from virtual models in computer aided design (CAD) software, transforming them into thin, virtual, horizontal cross-sections and then producing successive layers until the items are complete. As of June 2011, used for making models, prototype parts, and production-quality parts in relatively small numbers.
Reinforcement learning – an area of machine learning in computer science, concerned with how an agent ought to take actions in an environment so as to maximize some notion of cumulative reward.
Robot kinematics – applies geometry to the study of the movement of multi-degree of freedom kinematic chains that form the structure of robotic systems.
Robot locomotion – collective name for the various methods that robots use to transport themselves from place to place.
Robot programming –
Robotic mapping – the goal for an autonomous robot to be able to construct (or use ) a map or floor plan and to localize itself in it
Robotic surgery – computer-assisted surgery, and robotically-assisted surgery are terms for technological developments that use robotic systems to aid in surgical procedures.
Robot-assisted heart surgery –
Sensors – (also called detector) is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an (today mostly electronic) instrument.
Simultaneous localization and mapping – a technique used by robots and autonomous vehicles to build up a map within an unknown environment (without a priori knowledge), or to update a map within a known environment (with a priori knowledge from a given map), while at the same time keeping track of their current location.
Software engineering – the application of a systematic, disciplined, quantifiable approach to the design, development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software.
Space robotics – robots that operate in space, distinguishable from other spacecraft, such as satellites and flyby probes, by their locomotion and autonomous capabilities.
Speech processing – study of speech signals and the processing methods of these signals. The signals are usually processed in a digital representation, so speech processing can be regarded as a special case of digital signal processing, applied to speech signal. Aspects of speech processing includes the acquisition, manipulation, storage, transfer and output of digital speech signals.
Support vector machines – supervised learning models with associated learning algorithms that analyze data and recognize patterns, used for classification and regression analysis.
Swarm robotics – involves large numbers of mostly simple physical robots. Their actions may seek to incorporate emergent behavior observed in social insects (swarm intelligence).
Ant robotics – swarm robots that can communicate via markings, similar to ants that lay and follow pheromone trails.
Telepresence – refers to a set of technologies which allow a person to feel as if they were present, to give the appearance of being present, or to have an effect, via telerobotics, at a place other than their true location.
Ubiquitous robotics – integrating robotic technologies with technologies from the fields of ubiquitous and pervasive computing, sensor networks, and ambient intelligence.
Contributing fields
Robotics incorporates aspects of many disciplines including electronics, engineering, mechanics, software and arts. The design and control of robots relies on many fields knowledge, including:
General
Biology: –
Biomechanics –
Bioinformatics –
Computer science:
Artificial Intelligence – Machine learning, Deep learning, Artificial neural network
Computational linguistics –
Cloud computing –
Cybernetics –
Modal logic –
Engineering:
Chemical engineering –
Electrical engineering – Electronic engineering, Control engineering, Telecommunications engineering, Computer engineering (Software engineering, Internet of Things)
Mechanical engineering – Aerospace engineering, Automotive engineering
Mechatronics engineering – Microelectromechanical engineering, Acoustical engineering
Nanoengineering –
Optical engineering –
Safety engineering –
Fiction – Robotics technology and its implications are major themes in science fiction and have provided inspiration for robotics development and cause for ethical concerns. Robots are portrayed in short stories and novels, in movies, in TV shows, in theatrical productions, in web based media, in computer games, and in comic books. See List of fictional robots and androids.
Film – See Robots in film.
Literature – fictional autonomous artificial servants have a long history in human culture. Today's most pervasive trope of robots, developing self-awareness and rebelling against their creators, dates only from the early 20th century. See Robots in literature.
The Three Laws of Robotics in popular culture
Military science –
Psychology –
Cognitive science –
Behavioral science –
Philosophy –
Ethics –
Physics –
Dynamics –
Kinematics –
Fields of application – additionally, contributing fields include the specific field(s) a particular robot is being designed for. Expertise in surgical procedures and anatomy, for instance would be required for designing robotic surgery applications.
Related fields
Building automation –
Home automation –
Assistive technology
Cloud robotics
Robots
A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within.
Types of robots
Autonomous robots – robots that are not controlled by humans:
Aerobot – robot capable of independent flight on other planets
Android – humanoid robot; resembling the shape or form of a human
Automaton – early self-operating robot, performing exactly the same actions, over and over
Animatronic – a robot that is usually used for theme parks and movie/tvs show set.
Autonomous vehicle – vehicle equipped with an autopilot system, which is capable of driving from one point to another without input from a human operator
Ballbot – dynamically-stable mobile robot designed to balance on a single spherical wheel (i.e., a ball)
Cyborg – also known as a cybernetic organism, a being with both biological and artificial (e.g. electronic, mechanical or robotic) parts
Explosive ordnance disposal robot – mobile robot designed to assess whether an object contains explosives; some carry detonators that can be deposited at the object and activated after the robot withdraws
Gynoid – humanoid robot designed to look like a human female
Hexapod (walker) – a six-legged walking robot, using a simple insect-like locomotion
– reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks
3D printer
Insect robot – small robot designed to imitate insect behaviors rather than complex human behaviors.
Microbot – microscopic robots designed to go into the human body and cure diseases
Military robot – exosuit which is capable of merging with its user for enhanced strength, speed, handling, etc.
Mobile robot – self-propelled and self-contained robot that is capable of moving over a mechanically unconstrained course.
Cruise missile – robot-controlled guided missile that carries an explosive payload.
Music entertainment robot – robot created to perform music entertainment by playing custom made instrument or human developed instruments.
Nanobot – the same as a microbot, but smaller. The components are at or close to the scale of a nanometer (10−9 meters).
Prosthetic robot – programmable manipulator or device replacing a missing human limb.
Rover – a robot with wheels designed to walk on other planets' terrain
Service robot – machines that extend human capabilities.
Snakebot – robot or robotic component resembling a tentacle or elephant's trunk, where many small actuators are used to allow continuous curved motion of a robot component, with many degrees of freedom. This is usually applied to snake-arm robots, which use this as a flexible manipulator. A rarer application is the snakebot, where the entire robot is mobile and snake-like, so as to gain access through narrow spaces.
Surgical robot – remote manipulator used for keyhole surgery
Walking robot – robot capable of locomotion by walking. Owing to the difficulties of balance, two-legged walking robots have so far been rare, and most walking robots have used insect-like multilegged walking gaits.
By mode of locomotion
Mobile robots may be classified by:
The environment in which they travel:
Land or home robots. They are most commonly wheeled, but also include legged robots with two or more legs (humanoid, or resembling animals or insects).
Aerial robots are usually referred to as unmanned aerial vehicles (UAVs).
Underwater robots are usually called autonomous underwater vehicles (AUVs).
Polar robots, designed to navigate icy, crevasse filled environments
The device they use to move, mainly:
Legged robot – human-like legs (i.e. an android) or animal-like legs
Tracks
Wheeled robot
Robot components and design features
Actuator – motor that translates control signals into mechanical movement. The control signals are usually electrical but may, more rarely, be pneumatic or hydraulic. The power supply may likewise be any of these. It is common for electrical control to be used to modulate a high-power pneumatic or hydraulic motor.
Linear actuator – form of motor that generates a linear movement directly.
Delta robot – tripod linkage, used to construct fast-acting manipulators with a wide range of movement.
Drive power – energy source or sources for the robot actuators.
End-effector – accessory device or tool specifically designed for attachment to the robot wrist or tool mounting plate to enable the robot to perform its intended task. (Examples may include gripper, spot-weld gun, arc-weld gun, spray- paint gun, or any other application tools.)
Forward chaining – process in which events or received data are considered by an entity to intelligently adapt its behavior.
Haptic – tactile feedback technology using the operator's sense of touch. Also sometimes applied to robot manipulators with their own touch sensitivity.
Hexapod (platform) – movable platform using six linear actuators. Often used in flight simulators and fairground rides, they also have applications as a robotic manipulator.
See Stewart platform
– control of mechanical force and movement, generated by the application of liquid under pressure. c.f. pneumatics.
Kalman filter – mathematical technique to estimate the value of a sensor measurement, from a series of intermittent and noisy values.
Klann linkage – simple linkage for walking robots.
– gripper. A robotic 'hand'.
– articulated robot or manipulator based on a number of kinematic chains, actuators and joints, in parallel. c.f. serial manipulator.
Remote manipulator – manipulator under direct human control, often used for work with hazardous materials.
– articulated robot or manipulator with a single series kinematic chain of actuators. c.f. parallel manipulator.
Muting – deactivation of a presence-sensing safeguarding device during a portion of the robot cycle.
Pendant – Any portable control device that permits an operator to control the robot from within the restricted envelope (space) of the robot.
– control of mechanical force and movement, generated by the application of compressed gas. c.f. hydraulics.
Servo – motor that moves to and maintains a set position under command, rather than continuously moving
Servomechanism – automatic device that uses error-sensing negative feedback to correct the performance of a mechanism
Single point of control – ability to operate the robot such that initiation or robot motion from one source of control is possible only from that source and cannot be overridden from another source
Slow speed control – mode of robot motion control where the velocity of the robot is limited to allow persons sufficient time either to withdraw the hazardous motion or stop the robot
Stepper motor – motor whose rotation is divided into intervals called 'steps'. The motor can then rotate through a controlled number of steps which allows an exact awareness of the rotated distance.
– movable platform using six linear actuators, hence also known as a Hexapod
Subsumption architecture – robot architecture that uses a modular, bottom-up design beginning with the least complex behavioral tasks
Teach mode – control state that allows the generation and storage of positional data points effected by moving the robot arm through a path of intended motions
Specific robots
Aura (satellite) – robotic spacecraft launched by NASA in 2004 which collects atmospheric data from Earth
Chandra X-ray Observatory – robotic spacecraft launched by NASA in 1999 to collect astronomical data
Justin
Robonaut – development project conducted by NASA to create humanoid robots capable of using space tools and working in similar environments to suited astronauts
Unimate – the first off-the-shelf industrial robot, of 1961
Real robots by region
Robots from Australia
GuRoo
UWA Telerobot
Boeing MQ-28 Ghost Bat
Robots from Britain
Black Knight
eSTAR
Freddy II
George
Robop
Shadow Hand
Silver Swan
Talisman UUV
Wheelbarrow
Ameca
Robots from Canada
ANAT AMI-100
ANATROLLER ARE-100
ANATROLLER ARI-100
ANATROLLER ARI-50
ANATROLLER Dusty Duct Destroyer
Canadarm2
Dextre
hitchBOT
Robots from China
FemiSapien
Meinü robot
RoboSapien
Robosapien v2
RS Media
Sanbot robot
Xianxingzhe
Xiaoyi (Robot)
Robots from Croatia
DOK-ING EOD
TIOSS
Robots from Czech Republic
SyRoTek
Robots from France
Air-Cobot – collaborative mobile robot able to inspect aircraft during maintenance operations
Digesting Duck
Jessiko
Nabaztag
Nao
Robots from Germany
BionicKangaroo – biomimetic robot model designed by Festo
Care-Providing Robot FRIEND
LAURON
Marvin
Robots from Italy
iCub –
IsaacRobot
WalkMan
Leonardo's robot
Robots from Japan
AIBO
ASIMO
EMIEW
EMIEW 2
Enon
Evolta
Gakutensoku
HAL 5
HOAP
Ibuki
KHR-1
Omnibot
Plen
QRIO
R.O.B.
SCARA
Toyota Partner Robot
Wakamaru
Robots from Mexico
Don Cuco El Guapo
Robots from the Netherlands
Adelbrecht
Flame
Phobot
Senster
Robots from New Zealand
The Trons
Robots from Portugal
RAPOSA
Robots from Qatar
Robot jockey
Robots from Russia (or former Soviet Union)
Lunokhod 1
Lunokhod 2
Teletank
Robots from South Korea
Albert Hubo
EveR-1
HUBO
MAHRU
Musa
Robots from Spain
AISoy1
Maggie
REEM
Tico
Robots from Switzerland
Alice mobile robot –
E-puck mobile robot –
Pocketdelta robot –
Shameer shami robot –
Robots from the United States
Albert One –
Allen –
ATHLETE –
Atlas –
Baxter –
Ballbot –
avbotz Baracuda XIV –
Berkeley Lower Extremity Exoskeleton –
BigDog –
Boe-Bot –
CISBOT –
Coco –
Cog –
Crusher –
Dragon Runner –
EATR –
Elektro –
Entomopter –
Haile –
Hardiman –
HERO –
Johns Hopkins Beast –
Kismet –
Leonardo –
LOPES –
LORAX –
Nomad 200 –
Nomad rover –
Octobot (robot) –
Opportunity rover –
Programmable Universal Machine for Assembly –
Push the Talking Trash Can –
RB5X –
Robonaut –
Shakey the Robot –
Sojourner –
Spirit rover –
Turtle –
Unimate –
Zoë –
Pleo –
Robots from Vietnam
TOPIO –
International robots
European Robotic Arm –
Curiosity Rover for NASA on Mars Science Laboratory space mission –
Fictional robots by region
Fictional robots from the United Kingdom
From British literature
HAL 9000 (Arthur C. Clarke) –
From British radio
Marvin the Paranoid Android (Douglas Adams) –
From British television
Kryten (Rob Grant, Doug Naylor, David Ross, Robert Llewellyn) {Red Dwarf} –
Talkie Toaster – (Rob Grant, Doug Naylor, John Lenahan, David Ross) {Red Dwarf}
K-9 (Doctor Who) –
Robotboy – (Bob Camp, Charlie Bean, Heath Kenny, Prof Moshimo, Laurence Bouvard) {Robotboy}
K.T., Eric and Desiree in Robert's Robots
Fictional robots from the Czech Republich
From Czech plays
Daemon – (Karel Čapek) {R.U.R. (Rossum's Universal Robots)}
Helena – (Karel Čapek) {R.U.R. (Rossum's Universal Robots)}
Marius – (Karel Čapek) {R.U.R. (Rossum's Universal Robots)}
Primus – (Karel Čapek) {R.U.R. (Rossum's Universal Robots)}
Radius – (Karel Čapek) {R.U.R. (Rossum's Universal Robots)}
Sulla – (Karel Čapek) {R.U.R. (Rossum's Universal Robots)}
Fictional robots from France
From French ballets
Coppélia – (Arthur Saint-Leon, Léo Delibes) {Coppélia}
From French literature
Hadaly – (Auguste Villiers de l'Isle-Adam) {The Future Eve}
Fictional robots from Germany
From German film
Maschinenmensch – (Fritz Lang, Thea von Harbou, Brigitte Helm) {Metropolis}
From German literature
Maschinenmensch – (Thea von Harbou)
Olimpia – (E. T. A. Hoffmann) {Der Sandmann}
Fictional robots from Japan
From anime
Braiger – (Shigeo Tsubota, Tokichi Aoki) {Ginga Senpuu Braiger}
Combattler V – (Tadao Nagahama, Saburo Yatsude) {Super Electromagnetic Robo Combattler V}
Daimos – (Tadao Nagahama, Saburo Yatsude) {Brave Leader Daimos}
Groizer X – (Go Nagai) {Groizer X}
Mechander Robo – (Jaruhiko Kaido) {Mechander Robo (Gasshin Sentai Mekandaa Robo)}
Raideen – (Yoshiyuki Tomino, Tadao Nagahama) {Brave Raideen}
Trider G7 – (Hajime Yatate) {Invincible Robo Trider G7}
Voltes V – (Tadao Nagahama, Saburo Yatsude) {Super Electromagnetic Machine Voltes V}
From manga
Astro Boy – (Osamu Tezuka) {Astro Boy}
Doraemon – (Fujiko Fujio) {Doraemon}
Getter Robo – (Go Nagai, Ken Ishikawa) {Getter Robo}
Grendizer – (Go Nagai) {UFO Robo Grendizer}
Mazinger Z – (Go Nagai) {Mazinger Z}
Tetsujin 28 – (Mitsuteru Yokoyama) {Tetsujin 28 - Go!}
Fictional robots from the United States
From American comics
Amazo – (Gardner Fox) {DC Comics}
Annihilants – (Alex Raymond) {Flash Gordon}
From American film
C-3PO – (George Lucas, Anthony Daniels) {Star Wars}
ED-209 – (Paul Verhoeven, Craig Hayes, Phil Tippett) {RoboCop}
Fix-Its – (Burton Weinstein, Robert Cooper, Tony Hudson) {*batteries not included}
Gort – (Robert Wise, Harry Bates, Edmund H. North, Lock Martin) {The Day the Earth Stood Still}
Johnny Five – (Tim Blaney, Syd Mead) {Short Circuit}
R2-D2 – (George Lucas, Kenny Baker, Ben Burtt) {Star Wars}
Robby the Robot – (Fred M. Wilcox, Robert Kinoshita, Frankie Darro, Marvin Miller) {Forbidden Planet}
The Terminator – (James Cameron, Gale Anne Hurd) {The Terminator}
WALL-E and EVE – (Andrew Stanton, Ben Burtt, Elissa Knight) {WALL-E}
From American literature
Adam Link – (Eando Binder) {I, Robot}
Gnut – (Harry Bates) {Farewell to the Master}
Robbie – (Isaac Asimov) {I, Robot}
The Steam Man of the Prairies – (Edward S. Ellis) {The Steam Man of the Prairies}
Tik-Tok – (L. Frank Baum) {Ozma of Oz}
From American television
Bender Bending Rodriguez – (Matt Groening, David X. Cohen, John DiMaggio) {Futurama}
Bobert – (Ben Bocquelet, Kerry Shale) {The Amazing World of Gumball}
Cambot – Gypsy, Crow T. Robot, and Tom Servo (Joel Hodgson, Trace Beaulieu, Bill Corbett, Josh Weinstein, Jim Mallon, Patrick Brantseg) {Mystery Science Theater 3000}
Data – (Gene Roddenberry, Brent Spiner) {Star Trek: The Next Generation}
Grounder and Scratch – (Phil Hayes, Garry Chalk) {Adventures of Sonic the Hedgehog}
GIR – (Jhonen Vasquez, Rosearik Rikki Simons) {Invader Zim}
Jenny Wakeman – (Rob Renzetti, Janice Kawaye) {My Life as a Teenage Robot}
Robot B-9 – (Irwin Allen, Robert Kinoshita, Bob May, Dick Tufeld) {Lost in Space}
XR – (Larry Miller) {Buzz Lightyear of Star Command}
History of robotics
History of robots
Future of robotics
Artificial general intelligence
Soft robotics
Robotics development and development tools
Arduino – current platform of choice for small-scale robotic experimentation and physical computing.
CAD/CAM (computer-aided design and computer-aided manufacturing) – these systems and their data may be integrated into robotic operations.
Cleanroom – environment that has a low level of environmental pollutants such as dust, airborne microbes, aerosol particles and chemical vapors; often used in robot assembly.
Microsoft Robotics Developer Studio
Player Project
Robot Operating System
Gazebo, a robotics simulator
Robotics principles
Artificial intelligence – intelligence of machines and the branch of computer science that aims to create it.
Degrees of freedom – extent to which a robot can move itself; expressed in terms of Cartesian coordinates (x, y, and z) and angular movements (yaw, pitch, and roll).
Emergent behaviour – complicated resultant behaviour that emerges from the repeated operation of simple underlying behaviours.
Envelope (Space), Maximum – volume of space encompassing the maximum designed movements of all robot parts including the end-effector, workpiece, and attachments.
Humanoid – resembling a human being in form, function, or both.
Roboethics
Three Laws of Robotics – coined by the science fiction author Isaac Asimov, one of the first serious considerations of the ethics and robopsychological aspects of robotics.
Tool Center Point (TCP) – origin of the tool coordinate system.
Uncanny valley – hypothesized point at which humanoid robot behavior and appearance is so close to that of actual humans yet not precise or fully featured enough as to cause a sense of revulsion.
Robotics companies
Robotics organizations
FIRST (For Inspiration and Recognition of Science and Technology) – organization founded by inventor Dean Kamen in 1989 in order to develop ways to inspire students in engineering and technology fields. It founded various robotics competitions for elementary and high school students.
IEEE Robotics and Automation Society
Robotics Institute
SRI International
Robotics competitions
Robot competition
National ElectroniX Olympiad
ABU Robocon
BEST Robotics
Botball
DARPA Grand Challenge – prize competition for American autonomous vehicles, funded by the Defense Advanced Research Projects Agency, the most prominent research organization of the United States Department of Defense.
DARPA Grand Challenge (2004)
DARPA Grand Challenge (2005)
DARPA Grand Challenge (2007)
DARPA Robotics Challenge – prize competition funded by the US Defense Advanced Research Projects Agency. Held from 2012 to 2014, it aims to develop semi-autonomous ground robots that can do "complex tasks in dangerous, degraded, human-engineered environments."
Initial task requirements
Drive a utility vehicle at the site
Travel dismounted across rubble
Remove debris blocking an entryway
Open a door and enter a building
Climb an industrial ladder and traverse an industrial walkway
Use a tool to break through a concrete panel
Locate and close a valve near a leaking pipe
Connect a fire hose to a standpipe and turn on a valve
Teams making the finals
SCHAFT
IHMC Robotics
Tartan Rescue
MIT
RoboSimian
Team TRACLabs
WRECS
TROOPER
Defcon Robot Contest
Duke Annual Robo-Climb Competition
Eurobot
European Land-Robot Trial
FIRST Junior Lego League
FIRST Lego League
FIRST Robotics Competition
FIRST Tech Challenge
International Aerial Robotics Competition
Micromouse
RoboCup
Robofest
RoboGames
RoboSub
Student Robotics
UAV Outback Challenge
World Robot Olympiad
People influential in the field of robotics
Asimov, Isaac – science fiction author who coined the term "robotics", and wrote the three laws of robotics.
Čapek, Karel – Czech author who coined the term "robot" in his 1921 play, Rossum's Universal Robots.
Robotics in popular culture
Droid
List of fictional cyborgs
List of fictional robots and androids
List of fictional gynoids
Real Robot
Super Robot
Robot Hall of Fame
Waldo – a short story by Robert Heinlein, that gave its name to a popular nickname for remote manipulators.
See also
Outline of automation
Outline of machines
Outline of technology
References
External links
Autonomous Programmable Robot
Four-leg robot
Robotics Resources at CMU
Society of Robots
Research
The evolution of robotics research
Human Machine Integration Laboratory at Arizona State University
International Foundation of Robotics Research (IFRR)
International Journal of Robotics Research (IJRR)
Robotics and Automation Society (RAS) at IEEE
Robotics Network at IET
Robotics Division at NASA
Robotics and Intelligent Machines at Georgia Tech
Robotics Institute at Carnegie Mellon
Robotics at Imperial College London
Robotics
Robotics
-Robotics
Robotics | Outline of robotics | Engineering | 6,769 |
58,586,138 | https://en.wikipedia.org/wiki/BridgeOS | bridgeOS is an embedded operating system created and developed by Apple Inc. for use exclusively with its hardware. bridgeOS runs on the T series Apple silicon processors and operates devices such as the OLED touchscreen strip called the "Touch Bar", TouchID fingerprint sensor, SSD encryption, and cooling fans.
At boot time, the bootloader executes the bridgeOS kernel, then the bridgeOS kernel passes off to
the UEFI firmware.
bridgeOS is based on Apple's watchOS.
References
Apple Inc. operating systems
2016 software
Embedded operating systems | BridgeOS | Technology | 117 |
32,574,888 | https://en.wikipedia.org/wiki/FI6%20%28antibody%29 | FI6 is an antibody that targets a protein found on the surface of all influenza A viruses called hemagglutinin. FI6 is the only known antibody found to bind all 16 subtypes of the influenza A virus hemagglutinin and is hoped to be useful for a universal influenza virus therapy.
The antibody binds to the F domain HA trimer, and prevents the virus from attaching to the host cell. The antibody has been refined in order to remove any excess, unstable mutations that could negatively affect its neutralising ability, and this new version of the antibody has been termed "FI6v3"
Research
Researchers from Britain and Switzerland have previously found antibodies that work in Group 1 influenza A viruses or against most Group 2 viruses (CR8020), but not against both.
This team developed a method using single-cell screening to test very large numbers of human plasma cells, to increase their odds of finding an antibody even if it was extremely rare. When they identified FI6, they injected it into mice and ferrets and found that it protected the animals against infection by either a Group 1 or Group 2 influenza A virus.
Scientists screened 104,000 peripheral-blood plasma cells from eight recently infected or vaccinated donors for antibodies that recognize each of three diverse influenza strains: H1N1 (swine-origin) and H5N1 and H7N7 (highly pathogenic avian influenzas.) From one donor, they isolated four plasma cells that produced an identical antibody, which they called FI6. This antibody binds all 16 HA subtypes, neutralizes infection, and protects mice and ferrets from lethal infection. The most broadly reactive antibodies that had previously been discovered recognized either one group of HA subtypes or the other, highlighting how remarkable FI6 is in its ability to target the gamut of influenza subtypes.
Clinical implication
Researchers determined the crystal structure of the FI6 antibody when it was bound to H1 and H3 HA proteins. Sitting atop the HA spike is a globular head domain that binds to cellular receptors during viral entry and contains the major antigenic sites targeted by the immune system. Because of this selective pressure, the sequence in the head domain drifts enough to require an updated seasonal vaccine most years. A stalk domain connects the head to the viral membrane and is responsible for fusing viral and host membranes so that the pathogen can invade human cells. The immune system usually does not have a strong response to the partially hidden stalk domain, so portions of the stalk remain highly conserved across all influenza subtypes. The FI6 antibody makes extensive contacts with conserved parts of the stalk, thereby blocking HA from harpooning a sticky fusion peptide into the host membrane during viral entry.
The FI6 provides scientists with a broadly neutralizing antibody that recognizes all 16 HA subtypes, including emerging ones, such as H5N1. But, because the replication of the influenza virus is somewhat error-prone, the virus evolves as a quasispecies, and widespread use of antiviral drugs can lead to resistant strains. Such has been the case for oseltamivir and for the M2 ion channel blocker amantadine. Therefore, before considering FI6 as long-term prophylactic or therapeutic agent against seasonal influenza, we would first have to determine whether the influenza virus could quickly mutate the epitope targeted by FI6 and escape recognition by FI6 after exposure.
A more important clinical implication of this work is the identification of a universal neutralizing epitope in the HA stalk at the atomic level an important intellectual landmark for the development of a universal influenza vaccine. In the absence of the immunodominant head domain, isolated portions of the HA stalk that include the FI6 epitope and have already been shown to stimulate broad, but not universal, protective effects against H1N1 and H3N2 strains in vaccinated animals. Using protein engineering and adjuvants to focus the immune system on the FI6 epitope may be the critical next step along the path to a universal vaccine.
See also
Universal flu vaccine
References
External links
Science Magazine: A Neutralizing Antibody Selected from Plasma Cells That Binds to Group 1 and Group 2 Influenza A Hemagglutinins
GenBank accession:
heavy chain variable region:
JN234430, JN234435, JN234436, JN234437 (FI6VHv3), JN234438 (FI6VHv2), JN234439 (FI6VH)
Identical group AEL31297: JN234431, JN234432, JN234433, JN234434
kappa light chain variable region:
Identical group AEL31306: JN234440, JN234441, JN234442, JN234443
JN234444, JN234445, JN234446 (FI6VKv2), JN234447 (FI6VKv1), JN234448 (FI6VK)
Antibodies
Biological techniques and tools
Reagents for biochemistry | FI6 (antibody) | Chemistry,Biology | 1,065 |
63,940,009 | https://en.wikipedia.org/wiki/Sacred%20groves%20of%20Biodiversity%20Park%2C%20Visakhapatnam | The sacred groves is a zone of Biodiversity Park, Visakhapatnam located in the premises of Rani Chandramani Devi Government Hospital. It has more than 100 sacred plant species, which are medicinal herbs with religious importance. Many sacred plants are becoming rare and endangered. Hence they are to be reared, protected, and conserved. The zone was inaugurated on February 5, 2017, by Kambhampati Hari Babu, a member of parliament from Visakhapatnam, Andhra Pradesh.
Sacred plant species of the park in general
More than 300 tree species mentioned in holy books (Bhagvad Gita, Ramayana, Mahabharata, Bible, Quran, Tripitaka, Zend-Avesta, Guru Granth Sahib) related to different religions (Hinduism, Christianity, Islam, Jainism, Buddhism,
and Sikhism) are reared in different zones of the Biodiversity Park. Many tree species are commonly seen in more than one religion. For example, fig (Ficus carica) is almost common to all religions. Date palm (Phoenix dactylifera), olive (Olea europaea), pomegranate (Punica granatum), cypress (Cupressus sempervirens) are common to Christians and Muslims. Neem (Azadirachta indica), sacred fig or peepal or bodhi (Ficus religiosa), sal (Shorea robusta), sandal wood (Santalum album), bilva (Aegle marmelos) are common to Hindus, Buddhists and Jains. Banyan (Ficus bengalensis) and sacred fig (Ficus religiosa) are common to Hinduism, Buddhism, Jainsism, Judaism and Christianity. The maidenhair tree (Ginkgo biloba) is viewed as a sacred tree in all religions of China, Korea and Japan.
Some of the notable sacred plant species of the park are: maidenhair tree (Ginkgo biloba), Christmas tree (Araucaria excelsa), peepal/sacred fig/aswaddha (Ficus religiosa), banyan/marri/vata (Ficus benghalensis), ashoka tree (Saraca asoca), date palm (Phoenix dactylifera), Indian cedar / devadar (Cedrus deodara), cypress (Cupressus sempervirens), olive (Olea europaea), neem (Azadirachta indica), mango (Mangifera indica), kadamba (Anthocephalus cadamba), sandal wood (Santalum album), sami or jammi (Prosopis cineraria), bel, bilva or maredu (Aegle marmelos), moduga/flame of the forest (Butea monosperma), holy cross / calabash tree (Crescentia cujete), Indian lotus or padmam (Nelumbo nucifera), basilicum / tulasi (Ocimum sanctum), and rudraksha (Elaeocarpus ganitrus).
Sacred plant categories of the Sacred Grove Zone
The Sacred Groves Zone of the Biodiversity Park contains more than 100 plants under five categories namely Ganesha vana, Nakshatra vana, Raasi vana, Saptarishi vana and Navagraha vana. The pictures are shown in the gallery. Some plants or trees are common to more than one vana or garden. For example, raavi / peepal / sacred fig (Ficus religiosa) is common to Ganesha vana, Raasi vana, Saptarishi vana and Nakshtra vana. Similarly sandra / chandra / kachu (Acacia catechu) is common to Nakshatra vana, Navagraha vana and Raasi vana. Samee / jemmi (Prosopis cineraria) / (Prosopis spicigera) is common to Ganesha vana, Nakshatra vana, Navagraha vana and Raasi vana. Bilva / maredu / bael (Aegle marmelos) is common to Ganesha vana, Nakshatra vana and Saptarishi vana.
Ganesha vana – Ganesha garden with 21 plants
This consists of 21 leaves (Aeakavimshathi patraha) of 21 plant species connected with the worship of Lord Ganesha.
This might also be the same as the Siddhivinayak Mandala Vaatika, where the garden is designed as per sacred geometry dedicated to SiddhiVinayak, another name for Lord Ganesha.
A Mandala Vaatika, simply put, is a garden that is structured like a Mandala (i.e. in a circular geometric designs). However, in Vedic times, these gardens were created as per very specific mathematical calculations, patterns and measurements. Each deity and planet has their own unique Mandala geometry. These gardens were treated as sacred groves where one could meditate and experience the vibrations of these deities.
So, in ancient India one could meditate in a Rudra Mandala Vaatika, a Durga Mandala Vaatika, a Murugan Mandala Vaatika, a Varamahalakshmi Mandala Vaatika or even a Saptarishi Mandala Vaatika dedicated to the 7 most revered sages.
Nakshatra vana - garden with plants for 27 stars
The nakshatra vana comprises plant species connected with the 27 stars or star constellations of Indian astrology.
Raasi vana - garden with plants for 12 zodiac signs
This comprises plant species connected with the 12 signs in the zodiac system.
Saptarishi vana - garden of plants for seven great Indian sages
This comprises plant species connected with seven great Indian sages or rishis.
Navagraha vana - garden with plants for nine planets
This comprises nine plant species connected with nine planets or celestial bodies.
Gallery
Some notable sacred plant species:
See also
Biodiversity Park, Visakhapatnam
Dolphin Nature Conservation Society
References
Sacred groves
Botanical gardens in India
Medicinal plants
Biodiversity Heritage Sites of India
2017 establishments in Andhra Pradesh | Sacred groves of Biodiversity Park, Visakhapatnam | Biology | 1,300 |
469,324 | https://en.wikipedia.org/wiki/Volumetric%20efficiency | Volumetric efficiency (VE) in internal combustion engine engineering is defined as the ratio of the equivalent volume of the fresh air drawn into the cylinder during the intake stroke (if the gases were at the reference condition for density) to the volume of the cylinder itself. The term is also used in other engineering contexts, such as hydraulic pumps and electronic components.
Internal combustion engines
Volumetric Efficiency in an internal combustion engine design refers to the efficiency with which the engine can move the charge of fresh air into and out of the cylinders. It also denotes the ratio of equivalent air volume drawn into the cylinder to the cylinder's swept volume. This equivalent volume is commonly inserted into a mass estimation equation based upon Boyle's Gas Law. When VE is multiplied by the cylinder volume, an accurate estimate of cylinder air mass (charge) can be made for use in determining the required fuel delivery and spark timing for the engine.
The flow restrictions in the intake and exhaust systems create a reduction in the inlet flow which reduces the total mass delivery to the cylinder. Under some conditions, ram tuning may either increase or decrease the pumping efficiency of the engine. This happens when a favorable alignment of the pressure wave in the inlet (or exhaust) plumbing improves the flow through the valve. Increasing the pressure differential across the inlet valve typically increases VE throughout the naturally aspirated range. Adding intake manifold boost pressure from a supercharger or turbocharger can increase the VE, but the final calculation for cylinder airmass takes most of this benefit into account with the pressure term in n=PV/RT which is taken from the intake manifold pressure.
Many high performance cars use carefully arranged air intakes and tuned exhaust systems that use pressure waves to push air into and out of the cylinders, making use of the resonance of the system. Two-stroke engines are very sensitive to this concept and can use expansion chambers that return the escaping air-fuel mixture back to the cylinder. A more modern technique for four-stroke engines, variable valve timing, attempts to address changes in volumetric efficiency with changes in speed of the engine: at higher speeds the engine needs the valves open for a greater percentage of the cycle time to move the charge in and out of the engine.
Volumetric efficiencies above 100% can be reached by using forced induction such as supercharging or turbocharging. With proper tuning, volumetric efficiencies above 100% can also be reached by naturally aspirated engines. The limit for naturally aspirated engines is about 130%; these engines are typically of a DOHC layout with four valves per cylinder. This process is called inertial supercharging and uses the resonance of the intake manifold and the mass of the air to achieve pressures greater than atmospheric at the intake valve. With proper tuning (and dependent on the need for sound level control), VE's of up to 130% have been reported in various experimental studies.
More "radical" solutions include the sleeve valve design, in which the valves are replaced outright with a rotating sleeve around the piston, or alternately a rotating sleeve under the cylinder head. In this system the ports can be as large as necessary, up to that of the entire cylinder wall. However, there is a practical upper limit due to the strength of the sleeve, at larger sizes the pressure inside the cylinder can "pop" the sleeve if the port is too large.
Hydraulic pumps
Volumetric efficiency in a hydraulic pump refers to the percentage of actual fluid flow out of the pump compared to the flow out of the pump without leakage. In other words, if the flow out of a 100cc pump is 92cc (per revolution), then the volumetric efficiency is 92%. The volumetric efficiency will change with the pressure and speed a pump is operated at, therefore when comparing volumetric efficiencies, the pressure and speed information must be available. When a single number is given for volumetric efficiency, it will typically be at the rated pressure and speed.
Electronics
In electronics, volumetric efficiency quantifies the performance of some electronic function per unit volume, usually in as small a space as possible. This is desirable since advanced designs need to cram increasing functionality into smaller packages, for example, maximizing the energy stored in a battery powering a cellphone. Besides energy storage in batteries, the concept of volumetric efficiency appears in design and application of capacitors, where the "CV product" is a figure of merit calculated by multiplying the capacitance (C) by the maximum voltage rating (V), divided by the volume. The concept of volumetric efficiency can be applied to any measurable electronic characteristic, including resistance, capacitance, inductance, voltage, current, energy storage, etc.
See also
Two-stroke power valve system
Variable compression ratio
Notes
External links
2 Stroke Tuned Pipe (Expansion Chamber) Design Software
Engine technology
Two-stroke engine technology
Engineering ratios | Volumetric efficiency | Mathematics,Technology,Engineering | 1,002 |
844,254 | https://en.wikipedia.org/wiki/Wartenberg%20wheel | A Wartenberg wheel, also called a Wartenberg pinwheel or Wartenberg neurowheel, is a medical device for neurological use. The wheel was designed to test nerve reactions (sensitivity) as it rolled systematically across the skin. A Wartenberg wheel is generally made of stainless steel with a handle of approximately in length. The wheel, which has evenly spaced radiating sharp pins, rotates as it is rolled across the flesh. A disposable plastic version is available. Because of hygienic concerns, these devices are rarely used for medical purposes.
Robert Wartenberg, namesake of the Wartenberg wheel, is sometimes incorrectly credited as its inventor. According to Wartenberg himself, the device was in widespread use in Europe when he lived in Germany. While he did not invent it, he found it "an indispensable part of the outfit for everyday neurologic practice," and recommended its use to his colleagues in the US.
The Wartenberg wheel is also used as a sensation sex toy, and is often used to tickle a person (also called a ‘lee, short for “ticklee”) in the act of tickle fetishism. It is sometimes used in other settings while connected to a violet wand electrical device.
Clothing pattern-making can use a version of the Wartenberg wheel, called a pounce wheel, to transfer markings from paper to fabric. Pounce wheels resemble standard Wartenberg wheels in shape but have wooden or plastic handles.
See also
Tracing wheel
References
Further reading
Phillip Miller, Molly Devon, William A. Granzig: Screw the Roses, Send Me the Thorns: The Romance and Sexual Sorcery of Sadomasochism. Mystic Rose Books 1995,
Medical equipment
BDSM equipment
Neurology | Wartenberg wheel | Biology | 357 |
25,765,198 | https://en.wikipedia.org/wiki/Ichthyostegalia | Ichthyostegalia is an order of extinct amphibians, representing the earliest landliving vertebrates. The group is thus an evolutionary grade rather than a clade. While the group are recognized as having feet rather than fins, most, if not all, had internal gills in adulthood and lived primarily as shallow water fish and spent minimal time on land.
The group evolved from elpistostegalian fish in the late Devonian, or possibly in the middle Devonian. They continued to thrive as denizens of swampland and tidal channels throughout the period. They gave rise to the Temnospondyli and then disappeared during the transition to the Carboniferous.
Classification
Ichthyostegalia
Acanthostegidae
Acanthostega
Crassigyrinidae
Crassigyrinus
Densignathidae
Densignathus
Elginerpetontidae
Elginerpeton
Obruchevichthys
Ichthyostegidae
Hynerpeton
Ichthyostega
Jakubsonidae
Jakubsonia
Metaxygnathidae
Metaxygnathus
Sinostegidae
Sinostega
Tulerpetontidae
Tulerpeton
Ventastegidae
Ventastega
Ymeridae
Ymeria
Description
As first described, the order's sole member was Ichthyostega, from which the group takes its name. Ichthyostega was seen as transitional between fish and the early Stegocephalians, in that it combines a flat, heavily armoured stegocephalian skull with a fishlike tail bearing fin rays. Later work on Ichthyostega and other Devonian Labyrinthodonts shows that they also had more than 5 digits to each foot, in fact the whole foot being fin-like. Acanthostega, later found in the same locations, appears to have had a soft operculum and both it and Ichthyostega possessed functional internal gills as adults.
The feet are only known from Ichthyostega, Acanthostega, and Tulerpeton, but appear to be polydactyl in all forms with more than the usual five digits for tetrapods and were paddle-like. The tail bore true fin rays like those found in fish.
The Ichthyostegalians were large to medium-sized, with an adult size form most genera on the order of a meter or more. Their heads were flat and massive, with a host of labyrinthodont teeth. They were carnivorous and probably mainly ate fish, but may also have fed on washed-up carcasses of fish and other marine life, and hunted unwary arthropods and other invertebrate life along the tidal channels of the coal swamps. The vertebrae were complex and rather weak. At the close of the Devonian, forms with progressively stronger legs and vertebrae evolved, and the later groups lacked functional gills as adults. As adults, the animals would have been heavy and clumsy on land, and would probably appear more as fish that occasionally went ashore rather than proper land animals. All were however predominately aquatic and some spent all or nearly all their lives in water.
Genera
The order Ichthyostegalia was erected for Ichthyostega, and contained until the 1980s only three genera (Ichthyostega, Acanthostega and Tulerpeton). While Ichthyostegalia in principle contain the most basal of animals with toes rather than fins, Clack and Ahlberg uses it for all finds more advanced than Tiktaalik (the closest relative of tetrapods known to have retained paired fins rather than feet). Under this use, the number of known Devonian tetrapods have increased dramatically, so that the group now contain 12 genera: Most of the newer finds are redescriptions of very fragmentary finds, usually just the lower jaw. These were thought to have been from fish when found, but cladistic analyses indicate they are more advanced than Tiktaalik, though whether they actually had feet rather than fins is unknown. In order of discovery:
Ichthyostega
Acanthostega
Tulerpeton
Metaxygnathus
Elginerpeton
Obruchevichthys
Ventastega
Hynerpeton
Densignathus
Sinostega
Jakubsonia
Ymeria
References
Stegocephalians
Tetrapodomorph orders
Paleozoic amphibians
Paraphyletic groups | Ichthyostegalia | Biology | 908 |
45,429,453 | https://en.wikipedia.org/wiki/NGC%20695 | NGC 695 is a spiral galaxy located 450 million light years from the Earth, in the constellation of Aries. It has been described as an abnormal galaxy, and has the appearance of "a revolving tornado". Its arms are not tightly held together, and it is interacting with another small astronomical object.
Despite its distance of nearly 0.5 billion lightyears, the galaxy's extremely luminous starburst disk, bright IR and UV emissions earned it a spot in the NGC catalogue. VLASS 1.2 survey images indicate the presence of extended radio emission in the core of the galaxy- indicative of either an active SMBH, nuclear starburst, or both.
References
External links
Aries (constellation)
Lenticular galaxies
Peculiar galaxies
Luminous infrared galaxies
0695
01315
06844 | NGC 695 | Astronomy | 163 |
1,805,832 | https://en.wikipedia.org/wiki/Kilocalorie%20per%20mole | The kilocalorie per mole is a unit to measure an amount of energy per number of molecules, atoms, or other similar particles. It is defined as one kilocalorie of energy (1000 thermochemical gram calories) per one mole of substance. The unit symbol is written kcal/mol or kcal⋅mol−1. As typically measured, one kcal/mol represents a temperature increase of one degree Celsius in one liter of water (with a mass of 1 kg) resulting from the reaction of one mole of reagents.
In SI units, one kilocalorie per mole is equal to 4.184 kilojoules per mole (kJ/mol), which comes to approximately joules per molecule, or about 0.043 eV per molecule. At room temperature (25 °C, 77 °F, or 298.15 K), one kilocalorie per mole is approximately equal to 1.688 kT per molecule.
Even though it is not an SI unit, the kilocalorie per mole is still widely used in chemistry and biology for thermodynamical quantities such as thermodynamic free energy, heat of vaporization, heat of fusion and ionization energy. This is due to a variety of factors, including the ease with which it can be calculated based on the units of measure typically employed in quantifying a chemical reaction, especially in aqueous solution. In addition, for many important biological processes, thermodynamic changes are on a convenient order of magnitude when expressed in kcal/mol. For example, for the reaction of glucose with ATP to form glucose-6-phosphate and ADP, the free energy of reaction is −4.0 kcal/mol using the pH = 7 standard state.
References
Energy (physics)
Thermodynamics
Heat transfer
Units of chemical measurement | Kilocalorie per mole | Physics,Chemistry,Mathematics | 400 |
40,735,777 | https://en.wikipedia.org/wiki/IsaKidd%20refining%20technology | The IsaKidd Technology is a copper electrorefining and electrowinning technology that was developed independently by Copper Refineries Proprietary Limited (“CRL”), a Townsville, Queensland, subsidiary of MIM Holdings Limited (which is now part of the Glencore group of companies), and at the Falconbridge Limited (“Falconbridge”) now-dismantled Kidd Creek refinery that was at Timmins, Ontario. It is based around the use of reusable cathode starter sheets for copper electrorefining and the automated stripping of the deposited “cathode copper” from them.
Overview
The old way of electrorefining copper (pre-1978)
The usual process of electrorefining copper consists of placing a copper anode (about 99.5–99.7% pure copper) in sulfuric acid (H2SO4) bath of copper electrolyte, together with a cathode, and passing a current between the anode and cathode through an external circuit. At the applied electropotential, copper and less noble elements dissolve in the electrolyte, while elements more noble than copper, such as gold (Au) and silver (Ag), do not. Under the influence of the applied electrical potential, copper ions migrate from the anode and deposit on the cathode, forming cathode copper.
The current IsaKidd technology represents the merger of the copper refining technologies developed by the two different organisations. The initial Isa Process development in the late 1970s, with its reusable stainless-steel cathode starter sheets, represented an advance on the previous technology of single-use starter sheets of pure copper, the production of which was a labour-intensive process.
The production of the single-use starter sheets involved laying down a sheet of copper by electrolysis on each side of a “mother plate”. Generating the sheet took a day, and thousands of sheets could be needed every day. Originally, the copper starter sheets were separated from the mother plate manually, but over time the process was automated. In addition, limitations associated with the use of copper starter sheets meant that it was difficult to meet the purity specifications of some new copper applications that were, in the 1970s and 1980s, demanding higher quality copper.
IsaKidd process
The development of the Isa Process tank house technology at CRL eliminated the whole process and cost of producing the starter sheets by using stainless-steel permanent cathodes. It also included substantial automation of the process of inserting the permanent cathodes into the electrolytic cells and their subsequent removal and stripping of the sheets of deposited cathode copper. The labour force required to operate a refinery using the IsaKidd technology has been estimated at 60–70% less of that required for refineries using starter sheets.
MIM Holdings began marketing the Isa Process technology in 1980, as a result of demand from other refinery operators.
Falconbridge subsequently independently developed a similar process to improve operations at its Kidd Creek copper refinery, near Timmins, Ontario. The initial development of permanent cathodes was for internal use, but marketing of the Kidd Process was initiated in 1992 after requests from other refinery operators.
The two technologies were brought together as the IsaKidd Technology in 2006, when Xstrata bought Falconbridge.
The IsaKidd Technology now dominates global copper refining. It has been licensed to 102 users and Xstrata Technology, which markets the technology, reports on its website a total installed capacity of some 12 million tonnes per year (“t/y”) of copper production, as of October 2011. This is about 60% of the estimated 2011 global refined copper production of 19.7 million tonnes.
The development of the IsaKidd technology allowed increased productivity, reduced operating costs and the production of consistent, high-quality cathode copper.
History
Electrolytic refining of copper was first patented in England by James Elkington in 1865 and the first electrolytic copper refinery was built by Elkington in Burry Port, South Wales in 1869.
There were teething problems with the new technology. For example, the early refineries had trouble producing firm deposits on the cathodes. As a result, there was much secrecy between refinery operators as each strove to maintain a competitive edge.
The nature of the cathode used to collect the copper is a critical part of the technology. The properties of copper are highly susceptible to impurities. For example, an arsenic content of 0.1% can reduce the conductivity of copper by 23% and a bismuth content of just 0.001% makes copper brittle. The material used in the cathode must not contaminate the copper being deposited, or it will not meet the required specifications.
The current efficiency of the refining process depends, in part, on how close the anodes and cathodes can be placed in the electrolytic cell. This, in turn, depends on the straightness of both the anode and the cathode. Bumps and bends in either can lead to short-circuiting or otherwise affect the current distribution and also the quality of the cathode copper.
Prior to the development of the Isa Process technology, the standard approach was to use a starter sheet of high-purity copper as the initial cathode. These starter sheets are produced in special electrolytic cells by electrodeposition of copper for 24 hours onto a plate made of copper coated with oil (or treated with other similar face-separation materials) or of titanium. Thousands of sheets could be needed every day, and the original method of separating the starter sheet from the “mother plate” (referred to as “stripping”) was entirely manual.
Starter sheets are usually quite light. For example, the starter sheets used in the CRL refinery weighed 10 pounds (4.53 kilograms). Thus, they are thin and need to be handled carefully to avoid bending.
Over time, the formation of starter sheets was improved by mechanisation, but there was still a high labour input.
Once the starter sheets were formed, they had to be flattened, to reduce the likelihood of short circuits, and then cut, formed and punched to make loops from which the starter sheets are hung from conductive copper hanger bars in the electrolytic cells (see Figure 1).
The starter sheets are inserted in the refining cells and dissolved copper electrodeposits on them to produce the cathode copper product (see Figure 2). Because of the manufacturing cost of the starter sheets, refineries using them tend to keep them in the cells as long as possible, usually 12–14 days. On the other hand, the anodes normally reside in the cells for 24–28 days, meaning that there are two cathodes produced from each anode.
The starter sheets have a tendency to warp, due to the mechanical stresses they encounter and often need to be removed from the refining cells after about two days to be straightened in presses before being returned to the cells. The tendency to warp leads to frequent short-circuiting.
Due to their limitations, it is difficult for copper produced on starter sheets to meet modern specifications for the highest-purity copper.
The development of the Isa Process technology
The development of the Isa Process tank house technology had its beginning in the zinc industry. During the mid-1970s, MIM Holdings Limited (“MIM”) was considering building a zinc refinery in Townsville to treat the zinc concentrate produced by its Mount Isa operations. As a result, MIM staff visited the zinc smelters using the best-practice technology and found that modern electrolytic zinc smelters had adopted permanent cathode plate and mechanised stripping technology.
MIM recognised that the performance of traditional copper refineries was constrained by the poor cathode geometry inherent in using copper starter sheets.
MIM then developed a research program aimed at developing similar permanent cathode technology for copper refining. CRL had been operating in Townsville since 1959, using conventional starter-sheet technology and treating blister copper produced in the Mount Isa Mines Limited copper smelter at Mount Isa in Queensland. CRL incorporated the permanent cathode technology in its 1978 refinery modernisation project. The material initially selected was 316L stainless steel, stitch-welded to a 304L stainless-steel hanger bar. The hanger-bar assembly was then electroplated with copper to a thickness of 1.3 millimeters (“mm”) (later increased to 2.5 mm and then 3.0 mm to improve the corrosion resistance of the hanger bar) to approximately 15 mm down onto the blade, which provided sufficient electrical conductivity and gave the assembly some corrosion resistance.
Electrodeposited copper adheres quite firmly to the stainless steel so that it does not detach during refining. The vertical edges of the stainless steel plates are covered with tight-fitting polymer edge strips to prevent copper depositing around the edge of the cathode plate and so make it easier to strip the cathode copper from them. The bottom of the cathode plates were masked with a thin film of wax, again to prevent the copper depositing around the bottom edge. Wax was used rather than an edge strip to avoid having a ledge that would collect falling anode slimes and contaminate the cathode copper.
Wax was also used on the vertical edges to prolong the life of the vertical edge strip.
The original cathode stripping machine was based on that used at the Hikoshima plant of the Mitsui Mining and Smelting Company of Japan. However, considerable development work was necessary to modify the design to handle the copper cathodes, which were heavier than those at Hikoshima, and to process the cathode plates without damaging them. The machines also had to be redesigned to allow for waxing the sides and bottoms of the cathode plates to allow the next copper cathode sheets to be removed easily.
The stripping machines included receiving and discharge conveyors, washing, separation, cathode stacking and discharging, cathode plate separation for refurbishing, and the wax applications for the sides and bottoms of the cathode plates.
The original CRL stripping machine had the capability of stripping 250 cathode plates per hour.
The lower cost of the cathode plates compared to starter sheets means that shorter cathode cycle times are possible. The cycle time can range from 5 to 14 days, but a seven-day cathode cycle is common. This shorter cycle time improves current efficiency as less short circuits occur and there is less nodulation of the cathode surface.
Initially, other refinery operators regarded the developments at CRL with scepticism. Stainless steel had been tried unsuccessfully as mother-plate material for copper starter sheets. They suffered from rapid deterioration of their strippability, resulting in “an almost daily increase in difficulty of stripping”. However, following the success of early installations in Townsville, Timmins, and many other places, the permanent stainless steel cathode technology has had widespread introduction.
Moving into electrowinning plants
The Isa Process was originally developed for the CRL copper electrorefinery in Townsville. It was subsequently licensed to the Copper Range Company for its White Pine copper refinery.
The next licence issued was for an electrowinning application at the Broken Hill Associated Smelters (“BHAS”) lead smelter at Port Pirie, in South Australia. BHAS commissioned in 1985 a solvent extraction and electrowinning (“SX–EW”) to recover copper from copper–lead matte produced as a by-product of the lead smelting operations. The process used involves leaching the copper from the material using an acidic chloride–sulfate solution, followed by solvent extraction to concentrate the leached copper and electrowinning.
Electrowinning copper differs from electrorefining in that electrorefining uses a copper anode that is dissolved and redeposited on the cathode, while in electrowinning the copper is already in solution and is extracted from the solution by passing a current through the solution using an inert lead-alloy anode, and a cathode.
The chloride in the leach solution at Port Pirie proved to be a problem for the stainless steel cathodes of the Isa Process. A small amount of the chloride ions in the leach solution passed through the solvent into the electrolyte, leading to a reported chloride concentration of 80 milligrams per liter (“mg/L”) in the electrolyte. The presence of the chloride in the electrolyte caused pitting corrosion of the stainless steel cathode plates. After trying other types of stainless steel, BHAS switched to using titanium cathode plates.
Other electrowinning operations followed, including Gibraltar Mines’ McLeese Lake operation and Magma Copper’s San Manuel copper mine in 1986, the Mexicana de Cananea operation in Mexico in 1989, and the Gunpowder Copper Limited operation at Gunpowder in north-west Queensland 1990. These operations did not suffer the chloride corrosion problems experienced by BHAS.
The development of the Kidd Process technology
Falconbridge Limited in mid-1981 commissioned a copper smelter and refinery near Timmins, Ontario, to treat concentrate from its Kidd Mine. However, at the outset, the quality of the cathode copper produced in the Kidd refinery suffered from the presence of higher than usual concentrations of lead and selenium in the copper smelter’s anodes. Kidd cathode copper was not able to meet its customers’ specifications and obtaining product certification for the London Metal Exchange (“LME”) became a key focus.
After several process improvements were instigated, it was ultimately realised that the use of copper starter sheets was preventing the Kidd refinery meeting its cathode quality targets. Test work then began on the use of permanent stainless-steel cathodes. Preliminary tests using full-scale titanium blanks showed a reduction in the lead content of the cathode copper of a factor of four and a six-fold reduction in the selenium content, compared with the use of copper starter sheets.
The focus then shifted to developing a stripping machine, to develop stainless steel cathodes incorporating the existing header bars and evaluating edge-strip technology. The company’s board of directors gave approval for the conversion of the refinery to the Kidd technology in April 1985. The conversion was completed in 1986 and the Kidd refinery became the third to install permanent cathode and automated stripping technology.
Falconbridge began marketing the technology in 1992, after many requests from other refinery operators. Thus, the Kidd Process created competition between two suppliers of permanent cathode technology. The main differences between them were the cathode header bar, edge stripping and the stripping machine technology.
In contrast to the stainless steel header bar then used in the Isa Process cathode, the Kidd Process cathode used a solid copper header bar, which was welded onto the stainless steel sheet. This gave a lower voltage drop (by 8–10 millivolts) than the Isa Process cathode.
The Isa Process technology used the waxed edge at the bottom of the cathode plate to stop the copper depositing around the plate’s bottom to form a single mass of copper running from the top of one side of the cathode plate around the bottom to the top of the other side. The copper was stripped from the cathode plates as two separate sheets. The Kidd Process technology did not use wax, as it was thought that it could exacerbate the impurity problems with which the plant had been struggling. At Kidd, the stripping approach was to remove the copper from the cathode plate as a single V-shaped cathode product, akin to a taco shell.
The Kidd Process initially used a “carousel” stripping machine, but a linear installation was subsequently developed to provide machines with lower to medium stripping capacities for electrowinning plants and smaller refineries. The linear stripping machines, first installed in 1996, were more compact, less complex and had lower installation costs than the carousel machines.
New advances
Waxless cathode plates
As outlined above, the Kidd Process did not use wax on its permanent cathodes. This highlighted disadvantages associated with the use of wax by the Isa Process. Cathode copper consumers applied pressure to producers to remove residual wax from the cathode copper, and the use of wax also created “housekeeping” problems for Isa Process operators.
Consequently, MIM commenced a development program in 1997 aimed at eliminating the use of wax. This resulted in a new process called the Isa 2000 technology, which was able to produce single-sheet cathode (as opposed to the Kidd taco shell cathode) without using wax.
This was achieved by machining a 90° “V”-groove into the bottom edge of the cathode. The groove weakens the structure of the copper growing at the bottom edge of the cathode plate because the copper crystals grow perpendicular to the cathode plate from opposite sides of the groove, causing them to intersect at right angles to each other. A discontinuity in the structure is formed at the intersection that results in a weak zone, along which the copper splits during stripping.
Figure 4 is a microscope view of the cross-section a copper cathode growing at the tip of a cathode plate. The yellow lines show the orientation and direction of crystal growth.
Low-resistance cathodes
The standard Isa Process cathodes have slightly higher electrical resistance than solid-copper hanger bar systems used by the Kidd Process, meaning that there is a higher power cost. However, this cost is offset by greater reliability and predictability in the increase in resistance over time, allowing for maintenance planning.
The solid-copper hanger bars, on the other hand, lose electrical performance over a shorter period of time due to corrosive attack on the joint and sudden failure is possible. The maintenance costs of such systems are greater and less predictable. A trial of approximately 3000 solid-copper hanger bars, found over time a lower current efficiency in the solid-copper hanger bars of about 2.4%.
The MIM development team looked for other ways to reduce the resistance of the cathode plates and developed a new low-resistance cathode, which it called ISA Cathode BR. This new design extended the copper plating from 15–17 mm down the blade to approximately 55 mm, and it increased the thickness of the copper to 3.0 mm from the 2.5 mm used on the standard cathode.
The new cathode plate design was tested in the CRL refinery in Townsville and at Compania Minera Zaldivar in Chile. The Chilean results indicated the new cathode design had the potential to reduce power costs by approximately US$100,000 in 2003 for the plant, compared to using conventional Isa Process cathode designs.
Lower-cost stainless steel cathode plates
From 2001 to 2007, nickel prices rose from an average of US$5945 to US$37,216. Nickel is a key constituent of 316L stainless steel. This, combined with increases in some of the other constituents of the 316L alloy, prompted Xstrata Technology (by then the marketing organisation for the Isa Process technology) to seek an alternative material for the cathode plates.
Xstrata Technology personnel investigated the use of a new low-alloyed duplex stainless steel, LDX 2101 and 304L stainless steel. The LDX 2101 contains 1.5% nickel compared to 10–14% in 316L stainless steel.
LDX 2101 has superior mechanical strength to the 316L stainless steel, allowing thinner sheets to be used for the cathode plates. However, the flatness tolerance of commercially available LDX 2101 steel did not meet the required specifications. Xstrata Technology worked with a manufacturer to produce sheets that did meet the required flatness tolerance.
Xstrata Technology also had to develop a finish that allowed the surface to function in the same way as 316L.
Cathode plates using LDX 2010 have equivalent corrosion resistance to 316L plates.
The LDX 2101 alloy provides an alternative to the 316L stainless steel, with the selection depending on relatively prices of the various steels.
High corrosion resistance
The Kidd Process development team modified its cathode plates to cope with high-corrosion environments, such as the liberator cells used to remove contaminants in refineries and some high-corrosion environments in electrowinning plants.
The design of the plate features a stainless-steel jacket that surrounds a solid-copper hanger bar, protecting it from corrosion. A corrosion-resistant resin inside the stainless steel jacket protects the conductive interior weld between the header bar and the plate. The hanger bar is then finished with high-quality sealing to prevent ingress of electrolytes into the conductive interior weld.
This corrosion resistance electrode is marketed as the HP cathode plate.
The Kidd Process High Capacity Linear Machine
After the initial carousel stripping machine development and the later development of the linear stripping machine, Falconbridge personnel developed the Kidd Process High Capacity Linear Machine (“HCLM”). This machine included a loading and unloading system that was based on robotics.
The new design improved, among other things, the discharge area of the stripper. This had been a problem area for the carousel stripping machines, in which copper released from the cathode plate fell into an envelope and was then transferred to a material handling device. Copper that misbehaved and failed to transfer often required manual intervention. The new robot discharge system eliminated the free falling of the copper and physically transferred the released copper to the discharge location.
The birth of the combined IsaKidd technology
After Falconbridge’s 1992 decision to market the Kidd technology, the Falconbridge and the then MIM Process Technologies groups competed for the tank house technology market. Between 1992 and 2006, 25 Kidd technology licences were sold, while there were 52 Isa process licences sold in the same period.
Xstrata plc (now Glencore) took over MIM Holdings in 2003. The Isa Process technology continued to be developed and marketed by Xstrata Technology. Xstrata subsequently took over Falconbridge in 2006. The Kidd Process technology consequently became part of the Xstrata Technology tank house package and together they began to be marketed as IsaKidd, a name that represents the dual heritage of the technology.
The result has been a technology package that combined what were mutually regarded as the best of both versions. This combination led to the development of new stripping systems and new cathode designs are in development.
The variation in copper deposits on the cathode plates was one of the difficulties encountered with the earlier stripping machines. Areas of thin copper on the cathode plates, which are caused by short circuits, are difficult to separate from the stainless steel plate due to their lack of rigidity. Plates bearing such areas generally had to be rejected from the stripping machine and stripped manually. Similarly, sticky copper deposits (generally related to poor surface condition on the cathode plate, such as corroded surfaces or improper mechanical treatment), heavily nodulated cathode and laminated copper caused problems for stripping.
Stripping machine development focussed on developing a device that could be seen as a more accommodating and universal stripping machine that could handle cathode plates with problem copper deposits without rejecting them or slowing the stripping rate.
The result of this work was a new robotic cathode stripping machine. It incorporated the following features:
a stripping wedge that starts removing the copper from the top of the cathode plate and moves down to the bottom
guides to support the copper during the downwards motion to ensure that the copper does not strip prematurely
rollers designed to reduce the friction between the copper, the cathode plate and the wedge during the downward motion of the wedge
grippers that clamp the copper before it is pulled away from the cathode plate.
The stripping wedges are mounted on two robotic arms, one for each side of the cathode plate. These arms strip the copper from the plate and lay the sheets of cathode copper onto conveyors for them to be taken away for bundling.
Advantages of the IsaKidd Technology
Advantages cited for the IsaKidd technology include:
long life – the operational life of the permanent cathodes without repair is said to be over seven years under correct operating conditions for electrowinning applications and over 15 years for electrorefining applications
reduced labour costs – due to the elimination of the starter-sheet production process and the automation of cathode stripping. The average labour requirement for refineries based on the IsaKidd technology is 0.9 man-hours per tonne of cathode, compared to 2.4 man-hours/t for tank houses using starter sheets. Atlantic Copper personnel reported a figure of 0.43 man-hours/t for the Huelva refinery in Spain in 1998
no suspension loops – the suspension loops of starter sheets can corrode and thus cause cutting of the electrolytic cell liners. The lack of suspension loops also makes crane handling easier
improved cathode quality – due to the straight cathode plates, which eliminates short-circuiting, and the lack of bends and other surface irregularities reduces the capture of contaminants such as floating arsenic, antimony and bismuth and other slimes compounds. The elimination of the starter-sheet suspension loops also improved cathode quality. In SX–EW operations, the use of stainless-steel cathode plates eliminates lead flakes and other debris from the cathode copper.
improved current efficiency – this arises both from eliminating short circuits caused by bent and irregular electrodes and from the shorter cathode cycles possible with the use of the reusable cathode plates. Current efficiencies of over 98% are claimed
increased refining intensity – this reduces the number of electrolytic cells needed in a refinery and its capital cost because the gap between the anodes and the cathodes can be narrower due to the lower risk of short circuits and because the current density can be increased, making the refining process faster. Refineries operating with the IsaKidd technology can achieve current densities of 330 amperes per square meter (“A/m2”) of cathode area, whereas a refinery using starter sheets can only operate at around 240 A/m2
shorter cathode cycles – shorter cathode cycles are possible using the IsaKidd technology, which reduces the metal inventory and means that the refinery or SX–EW operator is paid more quickly
shorter anode cycles – the higher intensity of the refining also results in about a 12% reduction in anode cycle time, also reducing the metal inventory
uniform cathode copper sheets for ease of transport – the control over the dimensions of the copper sheets made possible by the IsaKidd technology, provides uniform cathode bundles that can be securely strapped and easily transported (see Figure 7)
improved safety – elimination of much of the manual handling leads to improved safety conditions in the workplace.
Staff of the Cyprus Miami copper refinery wrote after their installation of the Isa Process technology that: “It is now well proven that tankhouses applying stainless steel cathode technology can consistently produce high quality cathodes while operating at higher cathode current density and at a lower cathode spacing than those used in conventional tankhouses.”
References
Copper mining
Chemical processes
Industrial processes
Metallurgical processes
Electrolysis
Copper mining in the United States | IsaKidd refining technology | Chemistry,Materials_science | 5,642 |
1,872,874 | https://en.wikipedia.org/wiki/Zero%20ring | In ring theory, a branch of mathematics, the zero ring or trivial ring is the unique ring (up to isomorphism) consisting of one element. (Less commonly, the term "zero ring" is used to refer to any rng of square zero, i.e., a rng in which for all x and y. This article refers to the one-element ring.)
In the category of rings, the zero ring is the terminal object, whereas the ring of integers Z is the initial object.
Definition
The zero ring, denoted {0} or simply 0, consists of the one-element set {0} with the operations + and · defined such that 0 + 0 = 0 and 0 · 0 = 0.
Properties
The zero ring is the unique ring in which the additive identity 0 and multiplicative identity 1 coincide. (Proof: If in a ring R, then for all r in R, we have . The proof of the last equality is found here.)
The zero ring is commutative.
The element 0 in the zero ring is a unit, serving as its own multiplicative inverse.
The unit group of the zero ring is the trivial group {0}.
The element 0 in the zero ring is not a zero divisor.
The only ideal in the zero ring is the zero ideal {0}, which is also the unit ideal, equal to the whole ring. This ideal is neither maximal nor prime.
The zero ring is generally excluded from fields, while occasionally called as the trivial field. Excluding it agrees with the fact that its zero ideal is not maximal. (When mathematicians speak of the "field with one element", they are referring to a non-existent object, and their intention is to define the category that would be the category of schemes over this object if it existed.)
The zero ring is generally excluded from integral domains. Whether the zero ring is considered to be a domain at all is a matter of convention, but there are two advantages to considering it not to be a domain. First, this agrees with the definition that a domain is a ring in which 0 is the only zero divisor (in particular, 0 is required to be a zero divisor, which fails in the zero ring). Second, this way, for a positive integer n, the ring Z/nZ is a domain if and only if n is prime, but 1 is not prime.
For each ring A, there is a unique ring homomorphism from A to the zero ring. Thus the zero ring is a terminal object in the category of rings.
If A is a nonzero ring, then there is no ring homomorphism from the zero ring to A. In particular, the zero ring is not a subring of any nonzero ring.
The zero ring is the unique ring of characteristic 1.
The only module for the zero ring is the zero module. It is free of rank א for any cardinal number א.
The zero ring is not a local ring. It is, however, a semilocal ring.
The zero ring is Artinian and (therefore) Noetherian.
The spectrum of the zero ring is the empty scheme.
The Krull dimension of the zero ring is −∞.
The zero ring is semisimple but not simple.
The zero ring is not a central simple algebra over any field.
The total quotient ring of the zero ring is itself.
Constructions
For any ring A and ideal I of A, the quotient A/I is the zero ring if and only if , i.e. if and only if I is the unit ideal.
For any commutative ring A and multiplicative set S in A, the localization S−1A is the zero ring if and only if S contains 0.
If A is any ring, then the ring M0(A) of 0 × 0 matrices over A is the zero ring.
The direct product of an empty collection of rings is the zero ring.
The endomorphism ring of the trivial group is the zero ring.
The ring of continuous real-valued functions on the empty topological space is the zero ring.
Citations
References
Ring theory
Finite rings
0 (number) | Zero ring | Mathematics | 856 |
14,827,604 | https://en.wikipedia.org/wiki/HD%2013189 | HD 13189 is a star with an orbiting companion in the northern constellation of Triangulum constellation. With an apparent visual magnitude of +7.57, it is too faint to be visible to the normal human eye. The distance to this system is approximately 1,590 light years based on parallax measurements, and it is drifting further away with a radial velocity of 25.39 km/s. In 2005, a planetary companion or brown dwarf was announced in orbit around this star.
It has a spectral classification of K1II-III, making it a giant star that has evolved away from the main sequence after exhausting the hydrogen at its core. The mass is 1.2 times the Sun's, while measurements of the star's radius give estimates of . The atmosphere of the star displays short period radial velocity variations with a primary period of 4.89 days. This behavior is typical for giant K-type stars such as this and it is not the result of a close-orbit planetary companion.
HD 13189 b
HD 13189 b is an exoplanet or brown dwarf with mass ranges from 8 to 20 Jupiter mass. This object is located at a mean distance of 277 Gm (1.85 AU) from the star, taking 472 days to make one elliptical orbit.
This object was discovered in Tautenburg, Germany in 2005.
References
External links
013189
010085
Triangulum
K-type bright giants
Brown dwarfs
Durchmusterung objects
K-type giants
Planetary systems with one confirmed planet | HD 13189 | Astronomy | 315 |
49,183,357 | https://en.wikipedia.org/wiki/Cation-chloride%20cotransporter | The cation-chloride cotransporter (CCC) family (TC# 2.A.30) is part of the APC superfamily of secondary carriers. Members of the CCC family are found in animals, plants, fungi and bacteria. Most characterized CCC family proteins are from higher eukaryotes, but one has been partially characterized from Nicotiana tabacum (a plant), and homologous ORFs have been sequenced from Caenorhabditis elegans (worm), Saccharomyces cerevisiae (yeast) and Synechococcus sp. (blue green bacterium). The latter proteins are of unknown function. These proteins show sequence similarity to members of the APC family (TC #2.A.3). CCC family proteins are usually large (between 1000 and 1200 amino acyl residues), and possess 12 putative transmembrane spanners (TMSs) flanked by large N-terminal and C-terminal hydrophilic domains.
Function
CCC family proteins can catalyze NaCl/KCl symport, NaCl symport, or KCl symport depending on the system. The NaCl/KCl symporters are specifically inhibited by bumetanide while the NaCl symporters are specifically inhibited by thiazide. One member of the CCC family, the thiazide-sensitive NaCl cotransporter (NCC) of man is involved in 5% of the filtered load of NaCl in the kidney. Mutations in NCC cause the recessive Gitelman syndrome. NCC is a dimer in the membrane. It is regulated by RasGRP1.
Transport reaction
The generalized transport reaction for CCC family symporters is:
{Na+ + K+ + 2Cl−} (out) ⇌ {Na+ + K+ + 2Cl−} (in).
That for the NaCl and KCl symporters is:
{Na+ or K+ + Cl−} (out) ⇌ {Na+ or K+ + Cl−} (in).
Structure
NCC proteins are dimers in the membrane and contain 12 TMSs.
Two splice variants of NKCC2 are identical except for a 23 aa membrane domain. They have different affinities for Na+, K+ and Cl−. This segment (residues 216-233 in NKCC2) were examined for ion selectivity. Residue 216 affects K+ binding while residue 220 only affects Na+ binding. These two sites are presumed to be adjacent to each other.
Each of the major types of CCC family members in mammals exist as paralogous isoforms. These may differ in substrates transported. For example, of the four currently recognized KCl transporters, KCC1 and KCC4 both recognize KCl with similar affinities, but KCC1 exhibits anion selectivity: Cl− > SCN− = Br− > PO > I−, while KCl4 exhibits anion selectivity: Cl− > Br− > PO = I− > SCN−. Both are activated by cell swelling under hypotonic conditions. These proteins may cotransport water (H2O).
CCCs share a conserved structural scaffold that consists of a transmembrane transport domain followed by a cytoplasmic regulatory domain. Warmuth et al. (2009) determined the x-ray structure of the C-terminal domain of a CCC from the archaeon Mehanosarcina acetivorans (). It shows a novel fold of a regulatory domain, distantly related to universal stress proteins. The protein forms dimers in solution, consistent with the proposed dimeric organization of eukaryotic CCC transporters.
See also
APC Superfamily
SLC12A9
SLC12A8
Chloride potassium symporter 5
Transporter Classification Database
References
Protein families
Solute carrier family | Cation-chloride cotransporter | Biology | 824 |
46,474,025 | https://en.wikipedia.org/wiki/Inflatable%20seal | An inflatable seal is a type of rubber seal that inflates and deflates based on the presence of an inflation source. This allows the seal to accommodate a variable sealing gap. When pressure is applied internally to the seal, it inflates to conform to uneven surfaces and provides a reliable barrier from moisture, damp and other contaminants.
How It Works
An inflatable seal can be moulded into a concave, flat or convoluted configuration. Once an inflatable medium is placed between the seal and the force, the seal expands and rounds out to create a firm barrier between a mounting and striking surface.
The inflatable seal is uniquely designed to return to its original state once the source of inflation has been removed. This lets the technician move both the seal and the other object freely.
Applications
Inflatable seals can be utilized in an array of industries like electrical, environmental and the military to assist in the following applications to:
Squeeze to assist in the movement of materials
Produce a mechanical holding force
Stop equipment without damaging it
Push objects with any degree of force
Grip, hold, and lift objects while having the ability to retract the seal out of the way when deflated.
Seal off one environment
Different seal profiles will be used depending on the application. Common profiles include Castellated Profiles, Frog-leg Profiles, Footed Snap Profiles, Stem/Foot Profiles and Channel-fit Profiles. The choice of profile depends on the speed with which the seal must be sealed and unsealed, the pressure it is expected to withstand, and the distance and shape of the sealing gap.
Materials Used
Many elastomers are combined to create an inflatable seal. Some of the more commonly used materials are:
EPDM
Silicone
Viton
The following fabrics can be used to reinforce the seal:
Dacron
Kevlar
Nomex
Nylon
References
2.Inflatable Seals
Seals (mechanical) | Inflatable seal | Physics | 392 |
509,033 | https://en.wikipedia.org/wiki/Rivet | A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the tail. On installation, the deformed end is called the shop head or buck-tail.
Because there is effectively a head on each end of an installed rivet, it can support tension loads. However, it is much more capable of supporting shear loads (loads perpendicular to the axis of the shaft).
Fastenings used in traditional wooden boat building, such as copper nails and clinch bolts, work on the same principle as the rivet but were in use long before the term rivet was introduced and, where they are remembered, are usually classified among nails and bolts respectively.
History
Rivet holes have been found in Egyptian spearheads dating back to the Naqada culture of between 4400 and 3000 B.C. Archeologists have also uncovered many Bronze Age swords and daggers with rivet holes where the handles would have been. The rivets themselves were essentially short rods of metal, which metalworkers hammered into a pre-drilled hole on one side and deformed on the other to hold them in place.
Types
There are several types of rivets, designed to meet different cost, accessibility, and strength requirements:
Solid/round head rivets
Solid rivets are one of the oldest and most reliable types of fasteners, having been found in archaeological findings dating back to the Bronze Age. Solid rivets consist simply of a shaft and head that are deformed with a hammer or rivet gun. A rivet compression or crimping tool can also deform this type of rivet. This tool is mainly used on rivets close to the edge of the fastened material since the tool is limited by the depth of its frame. A rivet compression tool does not require two people and is generally the most foolproof way to install solid rivets.
Solid rivets are used in applications where reliability and safety count. A typical application for solid rivets can be found within the structural parts of aircraft. Hundreds of thousands of solid rivets are used to assemble the frame of a modern aircraft. Such rivets come with rounded (universal) or 100° countersunk heads. Typical materials for aircraft rivets are aluminium alloys (2017, 2024, 2117, 7050, 5056, 55000, V-65), titanium, and nickel-based alloys (e.g., Monel). Some aluminium alloy rivets are too hard to buck and must be softened by solution treating (precipitation hardening) prior to being bucked. "Ice box" aluminium alloy rivets harden with age, and must likewise be annealed and then kept at sub-freezing temperatures (hence the name "ice box") to slow the age-hardening process. Steel rivets can be found in static structures such as bridges, cranes, and building frames.
The setting of these fasteners requires access to both sides of a structure. Solid rivets are driven using a hydraulically, pneumatically, or electromagnetically actuated squeezing tool or even a handheld hammer. Applications where only one side is accessible require "blind" rivets.
Solid rivets are also used by some artisans in the construction of modern reproduction of medieval armour, jewellery and metal couture.
High-strength structural steel rivets
Until relatively recently, structural steel connections were either welded or riveted. High-strength bolts have largely replaced structural steel rivets. Indeed, the latest steel construction specifications published by AISC (the 14th Edition) no longer cover their installation. The reason for the change is primarily due to the expense of skilled workers required to install high-strength structural steel rivets. Whereas two relatively unskilled workers can install and tighten high-strength bolts, it normally takes four skilled workers to install rivets (warmer, catcher, holder, basher).
At a central location near the areas being riveted, a furnace was set up. Rivets were placed in the furnace and heated to approximately 900 °C or "cherry red". The rivet warmer or cook used tongs to remove individual rivets and throw them to a catcher stationed near the joints to be riveted. The catcher (usually) caught the rivet in a leather or wooden bucket with an ash-lined bottom. The catcher inserted the rivet into the hole to be riveted, then quickly turned to catch the next rivet. The holder up or holder on would hold a heavy bucking bar or dolly or another (larger) pneumatic jack against the round "shop head" of the rivet, while the riveter (sometimes two riveters) applied a hammer or pneumatic rivet hammer with a "rivet set" to the tail of the rivet, making it mushroom against the joint forming the "field head" into its final domed shape. Alternatively, the buck is hammered more or less flush with the structure in a counter-sunk hole. On cooling, the rivet contracted axially exerting the clamping force on the joint. Before the use of pneumatic hammers, e.g. in the construction of RMS Titanic, the person who hammered the rivet was known as the "basher".
The last commonly used high-strength structural steel rivets were designated ASTM A502 Grade 1 rivets.
Such riveted structures may be insufficient to resist seismic loading from earthquakes if the structure was not engineered for such forces, a common problem of older steel bridges. This is because a hot rivet cannot be properly heat treated to add strength and hardness. In the seismic retrofit of such structures, it is common practice to remove critical rivets with an oxygen torch, precision ream the hole, then insert a machined and heat-treated bolt.
Semi-tubular rivets
Semi-tubular rivets (also known as tubular rivets) are similar to solid rivets, except they have a partial hole (opposite the head) at the tip. The purpose of this hole is to reduce the amount of force needed for application by rolling the tubular portion outward. The force needed to apply a semi-tubular rivet is about 1/4 of the amount needed to apply a solid rivet. Tubular rivets are sometimes preferred for pivot points (a joint where movement is desired) since the swelling of the rivet is only at the tail. The type of equipment used to apply semi-tubular rivets ranges from prototyping tools to fully automated systems. Typical installation tools (from lowest to highest price) are hand set, manual squeezer, pneumatic squeezer, kick press, impact riveter, and finally PLC-controlled robotics. The most common machine is the impact riveter and the most common use of semi-tubular rivets is in lighting, brakes, ladders, binders, HVAC duct-work, mechanical products, and electronics. They are offered from 1/16-inch (1.6 mm) to 3/8-inch (9.5 mm) in diameter (other sizes are considered highly special) and can be up to 8 inches (203 mm) long. A wide variety of materials and platings are available, most common base metals are steel, brass, copper, stainless, aluminum and the most common platings are zinc, nickel, brass, tin. Tubular rivets are normally waxed to facilitate proper assembly. An installed tubular rivet has a head on one side, with a rolled-over and exposed shallow blind hole on the other.
Blind rivets
Blind rivets, commonly referred to as "pop" rivets (POP is the brand name of the original manufacturer, now owned by Stanley Engineered Fastening, a division of Stanley Black & Decker) are tubular and are supplied with a nail-like mandrel through the center which has a "necked" or weakened area near the head. The rivet assembly is inserted into a hole drilled through the parts to be joined and a specially designed tool is used to draw the mandrel through the rivet. The compression force between the head of the mandrel and the tool expands the diameter of the tube throughout its length, locking the sheets being fastened if the hole was the correct size. The head of the mandrel also expands the blind end of the rivet to a diameter greater than that of the drilled hole, compressing the fastened sheets between the head of the rivet and the head of the mandrel. At a predetermined tension, the mandrel breaks at the necked location. With open tubular rivets, the head of the mandrel may or may not remain embedded in the expanded portion of the rivet, and can come loose at a later time. More expensive closed-end tubular rivets are formed around the mandrel so the head of the mandrel is always retained inside the blind end after installation. "Pop" rivets can be fully installed with access to only one side of a part or structure.
Prior to the invention of blind rivets, installation of a rivet typically required access to both sides of the assembly: a rivet hammer on one side and a bucking bar on the other side. In 1916, Royal Navy reservist and engineer Hamilton Neil Wylie filed a patent for an "improved means of closing tubular rivets" (granted May 1917). In 1922 Wylie joined the British aircraft manufacturer Armstrong-Whitworth Ltd to advise on metal construction techniques; here he continued to develop his rivet design with a further 1927 patent that incorporated the pull-through mandrel and allowed the rivet to be used blind. By 1928, the George Tucker Eyelet Company, of Birmingham, England, produced a "cup" rivet based on the design. It required a separate GKN mandrel and the rivet body to be hand-assembled prior to use for the building of the Siskin III aircraft. Together with Armstrong-Whitworth, the Geo. Tucker Co. further modified the rivet design to produce a one-piece unit incorporating a mandrel and rivet. This product was later developed in aluminium and trademarked as the "POP" rivet. The United Shoe Machinery Co. produced the design in the U.S. as inventors such as Carl Cherry and Lou Huck experimented with other techniques for expanding solid rivets.
They are available in flat head, countersunk head, and modified flush head with standard diameters of 1/8, 5/32, and 3/16 inch. Blind rivets are made from soft aluminum alloy, steel (including stainless steel), copper, and Monel.
There are also , which are designed to take shear and tensile loads.
The rivet body is normally manufactured using one of three methods:
There is a vast array of specialty blind rivets that are suited for high strength or plastic applications. Typical types include:
Internally and externally locked structural blind rivets can be used in aircraft applications because, unlike other types of blind rivets, the locked mandrels cannot fall out and are watertight. Since the mandrel is locked into place, they have the same or greater shear-load-carrying capacity as solid rivets and may be used to replace solid rivets on all but the most critical stressed aircraft structures.
The typical assembly process requires the operator to install the rivet in the nose of the tool by hand and then actuate the tool. However, in recent years automated riveting systems have become popular in an effort to reduce assembly costs and repetitive disorders. The cost of such tools ranges from US$1,500 for auto-feed pneumatics to US$50,000 for fully robotic systems.
While structural blind rivets using a locked mandrel are common, there are also aircraft applications using "non-structural" blind rivets where the reduced, but still predictable, strength of the rivet without the mandrel is used as the design strength. A method popularized by Chris Heintz of Zenith Aircraft uses a common flat-head (countersunk) rivet which is drawn into a specially machined nosepiece that forms it into a round-head rivet, taking up much of the variation inherent in hole size found in amateur aircraft construction. Aircraft designed with these rivets use rivet strength figures measured with the mandrel removed.
Oscar rivets
Oscar rivets are similar to blind rivets in appearance and installation but have splits (typically three) along the hollow shaft. These splits cause the shaft to fold and flare out (similar to the wings on a toggle bolt's nut) as the mandrel is drawn into the rivet. This flare (or flange) provides a wide bearing surface that reduces the chance of rivet pull-out. This design is ideal for high-vibration applications where the back surface is inaccessible.
A version of the Oscar rivet is the Olympic rivet which uses an aluminum mandrel that is drawn into the rivet head. After installation, the head and mandrel are shaved off flush resulting in an appearance closely resembling a brazier head-driven rivet. They are used in the repair of Airstream trailers to replicate the look of the original rivets.
Drive rivet
A drive rivet is a form of blind rivet that has a short mandrel protruding from the head that is driven in with a hammer to flare out the end inserted in the hole. This is commonly used to rivet wood panels into place since the hole does not need to be drilled all the way through the panel, producing an aesthetically pleasing appearance. They can also be used with plastic, metal, and other materials and require no special setting tool other than a hammer and possibly a backing block (steel or some other dense material) placed behind the location of the rivet while hammering it into place. Drive rivets have less clamping force than most other rivets. Drive screws, possibly another name for drive rivets, are commonly used to hold nameplates into blind holes. They typically have spiral threads that grip the side of the hole.
Flush rivet
A flush rivet is used primarily on external metal surfaces where good appearance and the elimination of unnecessary aerodynamic drag are important. A flush rivet takes advantage of a countersunk or dimpled hole; they are also commonly referred to as countersunk rivets. Countersunk or flush rivets are used extensively on the exterior of aircraft for aerodynamic reasons such as reduced drag and turbulence. Additional post-installation machining may be performed to perfect the airflow.
Flush riveting was invented in America in the 1930s by Vladimir Pavlecka and his team at Douglas Aircraft. The technology was used by Howard Hughes in the design and production of his H-1 plane, the Hughes H-1 Racer.
Friction-lock rivet
These resemble an expanding bolt except the shaft snaps below the surface when the tension is sufficient. The blind end may be either countersunk ('flush') or dome-shaped.
One early form of blind rivet that was the first to be widely used for aircraft construction and repair was the Cherry friction-lock rivet. Originally, Cherry friction locks were available in two styles, hollow shank pull-through and self-plugging types. The pull-through type is no longer common; however, the self-plugging Cherry friction-lock rivet is still used for repairing light aircraft.
Cherry friction-lock rivets are available in two head styles, universal and 100-degree countersunk. Furthermore, they are usually supplied in three standard diameters, 1/8, 5/32 and 3/16 inch.
A friction-lock rivet cannot replace a solid shank rivet, size for size. When a friction lock is used to replace a solid shank rivet, it must be at least one size larger in diameter because the friction-lock rivet loses considerable strength if its center stem falls out due to vibrations or damage.
Rivet alloys, shear strengths, and driving condition
Self-piercing rivets
Self-pierce riveting (SPR) is a process of joining two or more materials using an engineered rivet. Unlike solid, blind and semi-tubular rivets, self-pierce rivets do not require a drilled or punched hole.
SPRs are cold-forged to a semi-tubular shape and contain a partial hole to the opposite end of the head. The end geometry of the rivet has a chamfered poke that helps the rivet pierce the materials being joined. A hydraulic or electric servo rivet setter drives the rivet into the material, and an upsetting die provides a cavity for the displaced bottom sheet material to flow. The SPR process is described in here SPR process.
The self-pierce rivet fully pierces the top sheet material(s) but only partially pierces the bottom sheet. As the tail end of the rivet does not break through the bottom sheet it provides a water or gas-tight joint. With the influence of the upsetting die, the tail end of the rivet flares and interlocks into the bottom sheet forming a low profile button.
Rivets need to be harder than the materials being joined. they are heat treated to various levels of hardness depending on the material's ductility and hardness. Rivets come in a range of diameters and lengths depending on the materials being joined; head styles are either flush countersunk or pan heads.
Depending on the rivet setter configuration, i.e. hydraulic, servo, stroke, nose-to-die gap, feed system etc., cycle times can be as quick as one second. Rivets are typically fed to the rivet setter nose from tape and come in cassette or spool form for continuous production.
Riveting systems can be manual or automated depending on the application requirements; all systems are very flexible in terms of product design and ease of integration into a manufacturing process.
SPR joins a range of dissimilar materials such as steel, aluminum, plastics, composites and pre-coated or pre-painted materials. Benefits include low energy demands, no heat, fumes, sparks or waste and very repeatable quality.
Compression rivets
Compression rivets are commonly used for functional or decorative purposes on clothing, accessories, and other items. They have male and female halves that press together, through a hole in the material. Double cap rivets have aesthetic caps on both sides. Single cap rivets have caps on just one side; the other side is low profile with a visible hole. Cutlery rivets are commonly used to attach handles to knife blades and other utensils.
Sizes
Rivets come in both inch series and metric series:
Imperial units (fractions of inches) with diameters such as 1/8″ or 5/16″.
Système international or SI units with diameters such as 3 mm, 8 mm.
The main official standards relate more to technical parameters such as ultimate tensile strength and surface finishing than physical length and diameter. They are:
Imperial
Rivet diameters are commonly measured in -inch increments and their lengths in -inch increments, expressed as "dash numbers" at the end of the rivet identification number. A "dash 3 dash 4" (XXXXXX-3-4) designation indicates a -inch diameter and -inch (or -inch) length. Some rivets lengths are also available in half sizes, and have a dash number such as –3.5 ( inch) to indicate they are half-size. The letters and digits in a rivet's identification number that precede its dash numbers indicate the specification under which the rivet was manufactured and the head style. On many rivets, a size in 32nds may be stamped on the rivet head. Other makings on the rivet head, such as small raised or depressed dimples or small raised bars indicate the rivet's alloy.
To become a proper fastener, a rivet should be placed in a hole ideally 4–6 thousandths of an inch larger in diameter. This allows the rivet to be easily and fully inserted, then setting allows the rivet to expand, tightly filling the gap and maximizing strength.
Metric
Rivet diameters and lengths are measured in millimeters. Conveniently, the rivet diameter relates to the drill required to make a hole to accept the rivet, rather than the actual diameter of the rivet, which is slightly smaller. This facilitates the use of a simple drill-gauge to check both rivet and drill are compatible. For general use, diameters between 2 mm – 20 mm and lengths from 5 mm – 50 mm are common. The design type, material and any finish is usually expressed in plain language (often English).
Applications
Before welding techniques and bolted joints were developed, metal-framed buildings and structures such as the Eiffel Tower, Shukhov Tower and the Sydney Harbour Bridge were generally held together by riveting, as were automobile chassis. Riveting is still widely used in applications where light weight and high strength are critical, such as in an aircraft. Sheet metal alloys used in aircraft skins are generally not welded, because the aircraft in high-speed flight skins will be stretched, extrusion may occur deformation and change in material properties. Riveting can reduce the vibration transmission between joints, thereby reducing the risk of cracking. The firmness is better and more reliable against such repeated stress changes. In order to reduce air resistance, countersunk rivets are generally used in aircraft skins.
A large number of countries used rivets in the construction of armored tanks during World War II, including the M3 Lee (General Grant) manufactured in the United States. However, many countries soon learned that rivets were a large weakness in tank design since if a tank was hit by a large projectile it would dislocate the rivets and they would fly around the inside of the tank and injure or kill the crew, even if the projectile did not penetrate the armor. Some countries such as Italy, Japan, and Britain used rivets in some or all of their tank designs throughout the war for various reasons, such as lack of welding equipment or inability to weld very thick plates of armor effectively.
Blind rivets are used almost universally in the construction of plywood road cases.
Common but more exotic uses of rivets are to reinforce jeans and to produce the distinctive sound of a sizzle cymbal.
Joint analysis
The stress and shear in a rivet are analyzed like a bolted joint. However, it is not wise to combine rivets with bolts and screws in the same joint. Rivets fill the hole where they are installed to establish a very tight fit (often called an interference fit). It is difficult or impossible to obtain such a tight fit with other fasteners. The result is that rivets in the same joint with loose fasteners carry more of the load—they are effectively stiffer. The rivet can then fail before it can redistribute load to the other loose-fit fasteners like bolts and screws. This often causes catastrophic failure of the joint when the fasteners unzip. In general, a joint composed of similar fasteners is the most efficient because all fasteners reach capacity simultaneously.
Installation
Solid and semi-tubular rivets
There are several methods for installing solid rivets.
Manual with hammer and handset or bucking bar
Pneumatic hammers
Handheld squeezers
Riveting machines
Pin hammer, rivet set
Rivets small enough and soft enough are often bucked. In this process, the installer places a rivet gun against the factory head and holds a bucking bar against the tail or a hard working surface. The bucking bar is a specially shaped solid block of metal. The rivet gun provides a series of high-impulse forces that upsets and work hardens the tail of the rivet between the work and the inertia of the bucking bar. Rivets that are large or hard may be more easily installed by squeezing instead. In this process, a tool in contact with each end of the rivet clinches to deform the rivet.
Rivets may also be upset by hand, using a ball-peen hammer. The head is placed in a special hole made to accommodate it, known as a rivet-set. The hammer is applied to the buck-tail of the rivet, rolling an edge so that it is flush against the material.
Testing
Solid rivets for construction
A hammer is also used to "ring" an installed rivet, as a non-destructive test for tightness and imperfections. The inspector taps the head (usually the factory head) of the rivet with the hammer while touching the rivet and base plate lightly with the other hand and judges the quality of the audibly returned sound and the feel of the sound traveling through the metal to the operator's fingers. A rivet tightly set in its hole returns a clean and clear ring, while a loose rivet produces a recognizably different sound.
Testing of blind rivets
A blind rivet has strength properties that can be measured in terms of shear and tensile strength. Occasionally rivets also undergo performance testing for other critical features, such as pushout force, break load and salt spray resistance. A standardized destructive test according to the Inch Fastener Standards is widely accepted.
The shear test involves installing a rivet into two plates at specified hardness and thickness and measuring the force necessary to shear the plates. The tensile test is basically the same, except that it measures the pullout strength. Per the IFI-135 standard, all blind rivets produced must meet this standard. These tests determine the strength of the rivet, and not the strength of the assembly. To determine the strength of the assembly a user must consult an engineering guide or the Machinery's Handbook.
Alternatives
Adhesives
Bolted joints
Brazing
Clinching
Folded joints
Nails
Screws
Soldering
Welding
See also
References
Bibliography
External links
Popular Science, November 1941, "Self-Setting Explosive Rivet Speeds Warplane Building" system used by both the US and Germany in World War Two for aircraft assembly – see bottom half of page
Four Methods of Flush Riveting, film made by Disney Studios during World War Two
"Hold Everything", February 1946, Popular Science new rivet types developed during World War Two
"Blind Rivets they get it all together". Popular Science, October 1975, pp. 126–128.
"RMS Titanic Remembered" – The Lads in the Shipyard
Articles containing video clips
Mechanical fasteners
Metalworking
Structural steel
Textile closures | Rivet | Engineering | 5,566 |
18,610,161 | https://en.wikipedia.org/wiki/Marker%20vaccine | A marker vaccine is a vaccine which allows for immunological differentiation (or segregation) of infected from vaccinated animals, and is also referred to as a DIVA (or SIVA) vaccine [Differentiation (or Segregation) of infected from vaccinated animals] in veterinary medicine. In practical terms, this is most often achieved by omitting an immunogenic antigen present in the pathogen being vaccinated against, thus creating a negative marker of vaccination. In contrast, vaccination with traditional vaccines containing the complete pathogen, either attenuated or inactivated, precludes the use of serology (e.g. analysis of specific antibodies in body fluids) in epidemiological surveys in vaccinated populations.
Apart from the obvious advantage of allowing continued serological monitoring of vaccinated individuals, cohorts or populations; the serological difference between vaccinated individuals and individuals that were exposed to the pathogen, and were contagious, can be used to continuously monitor the efficacy and safety of the vaccine.
References
Animal disease control
Vaccination | Marker vaccine | Biology | 219 |
17,824,815 | https://en.wikipedia.org/wiki/Galactic%20anticenter | The galactic anticenter is a direction in space directly opposite to the Galactic Center, as viewed from Earth. This direction corresponds to a point on the celestial sphere.
From the perspective of an observer on Earth, the galactic anticenter is located in the constellation Auriga, and the Crab nebula and the bright star Beta Tauri (Elnath) appear nearest this point. For binocular and telescope observers in dark sky locations, the magnitude 8.5 star HIP 27180 appears closest to this point.
Location
In terms of the galactic coordinate system, the Galactic Center (in Sagittarius) corresponds to a longitude of 0°, while the anticenter is located exactly at 180°. In the equatorial coordinate system, the anticenter is found at roughly RA 05h 46m, dec +28° 56'.
See also
Anticenter shell
Galactic Center
References
Anticenter
Anticenter
Auriga
Galactic Center | Galactic anticenter | Astronomy | 191 |
9,174,778 | https://en.wikipedia.org/wiki/Microprocessor%20development%20board | A microprocessor development board is a printed circuit board containing a microprocessor and the minimal support logic needed for an electronic engineer or any person who wants to become acquainted with the microprocessor on the board and to learn to program it. It also served users of the microprocessor as a method to prototype applications in products.
Unlike a general-purpose system such as a home computer, usually a development board contains little or no hardware dedicated to a user interface. It will have some provision to accept and run a user-supplied program, such as downloading a program through a serial port to flash memory, or some form of programmable memory in a socket in earlier systems.
History
The reason for the existence of a development board was solely to provide a system for learning to use a new microprocessor, not for entertainment, so everything superfluous was left out to keep costs down. Even an enclosure was not supplied, nor a power supply. This is because the board would only be used in a "laboratory" environment so it did not need an enclosure, and the board could be powered by a typical bench power supply already available to an electronic engineer.
Microprocessor training development kits were not always produced by microprocessor manufacturers. Many systems that can be classified as microprocessor development kits were produced by third parties, one example is the Sinclair MK14, which was inspired by the official SC/MP development board from National Semiconductor, the "NS introkit".
Although these development boards were not designed for hobbyists, they were often bought by them because they were the earliest cheap microcomputer devices available. They often added all kinds of expansions, such as more memory, a video interface etc. It was very popular to use (or write) an implementation of Tiny Basic. The most popular microprocessor board, the KIM-1, received the most attention from the hobby community, because it was much cheaper than most other development boards, and more software was available for it (Tiny Basic, games, assemblers), and cheap expansion cards to add more memory or other functionality. More articles were published in magazines like "Kilobaud Microcomputing" that described home-brew software and hardware for the KIM-1 than for other development boards.
Today some chip producers still release "test boards" to demonstrate their chips, and to use them as a "reference design". Their significance these days is much smaller than it was in the days that such boards, (the KIM-1 being the canonical example) were the only low cost way to get "hands-on" acquainted with microprocessors..
Features
The most important feature of the microprocessor development board was the ROM-based built-in machine language monitor, or "debugger" as it was also sometimes called. Often the name of the board was related to the name of this monitor program, for example the name of the monitor program of the KIM-1 was "Keyboard Input Monitor", because the ROM-based software allowed entry of programs without the rows of cumbersome toggle switches that older systems used. The popular Motorola 6800-based systems often used a monitor with a name with the word "bug" for "debugger" in it, for example the popular "MIKBUG".
Input was normally done with a hexadecimal keyboard, using a machine language monitor program, and the display only consisted of a 7-segment display. Backup storage of written assembler programs was primitive: only a cassette type interface was typically provided, or the serial Teletype interface was used to read (or punch) a papertape.
Often the board has some kind to expansion connector that brought out all the necessary CPU signals, so that an engineer could build and test an experimental interface or other electronic device.
External interfaces on the bare board were often limited to a single RS-232 or current loop serial port, so a terminal, printer, or Teletype could be connected.
List of historical development boards
8085AAT, an Intel 8085 microprocessor training unit from Paccom
CDP18S020 evaluation board for the RCA CDP1802 microprocessor
EVK 300 6800 single board from American Microsystems (AMI)
Explorer/85 expandable learning system based on the 8085, by Netronics's research and development ltd.
ITT experimenter used switches and LEDs, and an Intel 8080
JOLT was designed by Raymond M. Holt, co-founder of Microcomputer Associates, Incorporated.
KIM-1 the development board for the MOS Technology/Rockwell/Synertek 6502 microprocessor. The name KIM is short for "keyboard input monitor"
SYM-1 a slightly improved KIM-1 with improved software, more memory, and I/O. Also known as the VIM
AIM-65 an improved KIM-1 with an alpha-numerical LED display, and a built-in printer.
The KIM-1 also lead to some unofficial copies, such as the super-KIM and the Junior from the magazine Elektor, and the MCS Alpha 1
LC80 by Kombinat Mikroelektronik Erfurt
MAXBOARD development board for the Motorola 6802.
MEK6800D2 the official development board for the Motorola 6800 microprocessor. The name of the monitor software was MIKBUG
MicroChroma 68 color graphics kit. Developed by Motorola to demonstrate their new 6847 video display processor. The monitor software was called TVBUG
Motorola EXORciser development system (rack based) for the Motorola 6809
Microprofessor I (MPF-1) Z80 development and training system by Acer
Tangerine Microtan 65 6502 development system with VDU, that could be expanded to a more capable system.
MST-80B 8080 training system by the Lawrence Livermore National Laboratory
NS introkit by National Semiconductor featuring the SC/MP, the predecessor to the Sinclair MK14
NRI microcomputer, a system developed to teach computer courses by McGraw-Hill and the National Radio Institute (NRI)
MK14 Training system for the SC/MP microprocessor from Sinclair Research Ltd.
SDK-80 Intel's development board for their 8080 microprocessor
SDK-51 Intel's development board for their Intel MCS-51
SDK-85 Intel's development board for their 8085 microprocessor
SDK-86 Intel's development board for their 8086 microprocessor
Siemens Microset-8080 boxed system based on an 8080.
Signetics Instructor 50 based on the Signetics 2650.
SGS-ATES Nanocomputer Z80.
RCA Cosmac Super Elf by RCA . a 1802 learning system with an RCA 1861 Video Display Controller.
TK-80 the development board for NEC's clone of Intel's i8080, the μPD 8080A
TM 990/100M evaluation board for the Texas Instruments TMS9900
TM 990/180M evaluation board for the Texas Instruments TMS9800
XPO-1 Texas Instruments development system for the PPS-4/1 line of microcontrollers
DSP evaluation boards
A DSP evaluation board, sometimes also known as a DSP starter kit (DSK) or a DSP evaluation module, is an electronic board with a digital signal processor used for experiments, evaluation and development. Applications are developed in DSP Starter Kits using software usually referred as an integrated development environment (IDE). Texas Instruments and Spectrum Digital are two companies who produce these kits.
Two examples are the DSK 6416 by Texas Instruments, based on the TMS320C6416 fixed point digital signal processor, a member of C6000 series of processors that is based on VelociTI.2 architecture, and the DSK 6713 by Texas Instruments, which was developed in cooperation with Spectrum Digital, based on the TMS320C6713 32-bit floating point digital signal processor, which allows for programming in C and assembly.
See also
Embedded system
Intel system development kit
Single-board computer
Single-board microcontroller
References
Early microcomputers
Telecommunications engineering | Microprocessor development board | Engineering | 1,708 |
27,636,080 | https://en.wikipedia.org/wiki/Thermochemical%20cycle | In chemistry, thermochemical cycles combine solely heat sources (thermo) with chemical reactions to split water into its hydrogen and oxygen components. The term cycle is used because aside of water, hydrogen and oxygen, the chemical compounds used in these processes are continuously recycled.
If work is partially used as an input, the resulting thermochemical cycle is defined as a hybrid one.
History
This concept was first postulated by Funk and Reinstrom (1966) as a maximally efficient way to produce fuels (e.g. hydrogen, ammonia) from stable and abundant species (e.g. water, nitrogen) and heat sources. Although fuel availability was scarcely considered before the oil crisis efficient fuel generation was an issue in important niche markets. As an example, in the military logistics field, providing fuels for vehicles in remote battlefields is a key task. Hence, a mobile production system based on a portable heat source (a nuclear reactor was considered) was being investigated with utmost interest.
Following the oil crisis, multiple programs (Europe, Japan, United States) were created to design, test and qualify such processes for purposes such as energy independence. High-temperature (around operating temperature) nuclear reactors were still considered as the likely heat sources. However, optimistic expectations based on initial thermodynamics studies were quickly moderated by pragmatic analyses comparing standard technologies (thermodynamic cycles for electricity generation, coupled with the electrolysis of water) and by numerous practical issues (insufficient temperatures from even nuclear reactors, slow reactivities, reactor corrosion, significant losses of intermediate compounds with time...). Hence, the interest for this technology faded during the next decades, or at least some tradeoffs (hybrid versions) were being considered with the use of electricity as a fractional energy input instead of only heat for the reactions (e.g. Hybrid sulfur cycle). A rebirth in the year 2000 can be explained by both the new energy crisis, demand for electricity, and the rapid pace of development of concentrated solar power technologies whose potentially very high temperatures are ideal for thermochemical processes, while the environmentally friendly side of thermochemical cycles attracted funding in a period concerned with a potential peak oil outcome.
Principles
Water-splitting via a single reaction
Consider a system composed of chemical species (e.g. water splitting) in thermodynamic equilibrium at constant pressure and thermodynamic temperature T:
H2O(l) H2(g) + 1/2 O2(g) (1)
Equilibrium is displaced to the right only if energy (enthalpy change ΔH for water-splitting) is provided to the system under strict conditions imposed by thermodynamics:
one fraction must be provided as work, namely the Gibbs free energy change ΔG of the reaction: it consists of "noble" energy, i.e. under an organized state where matter can be controlled, such as electricity in the case of the electrolysis of water. Indeed, the generated electron flow can reduce protons (H+) at the cathode and oxidize anions (O2−) at the anode (the ions exist because of the chemical polarity of water), yielding the desired species.
the other one must be supplied as heat, i.e. by increasing the thermal agitation of the species, and is equal by definition of the entropy to the absolute temperature T times the entropy change ΔS of the reaction.
(2)
Hence, for an ambient temperature T° of 298K (kelvin) and a pressure of 1 atm (atmosphere (unit)) (ΔG° and ΔS° are respectively equal to 237 kJ/mol and 163 J/mol/K, relative to the initial amount of water), more than 80% of the required energy ΔH must be provided as work in order for water-splitting to proceed.
If phase transitions are neglected for simplicity's sake (e.g. water electrolysis under pressure to keep water in its liquid state), one can assume that ΔH et ΔS do not vary significantly for a given temperature change. These parameters are thus taken equal to their standard values ΔH° et ΔS° at temperature T°. Consequently, the work required at temperature T is,
(3)
As ΔS° is positive, a temperature increase leads to a reduction of the required work. This is the basis of high-temperature electrolysis. This can also be intuitively explained graphically.
Chemical species can have various excitation levels depending on the absolute temperature T, which is a measure of the thermal agitation. The latter causes shocks between atoms or molecules inside the closed system such that energy spreading among the excitation levels increases with time, and stop (equilibrium) only when most of the species have similar excitation levels (a molecule in a highly excited level will quickly return to a lower energy state by collisions) (Entropy (statistical thermodynamics)).
Relative to the absolute temperature scale, the excitation levels of the species are gathered based on standard enthalpy change of formation considerations; i.e. their stabilities. As this value is null for water but strictly positive for oxygen and hydrogen, most of the excitation levels of these last species are above the ones of water. Then, the density of the excitation levels for a given temperature range is monotonically increasing with the species entropy. A positive entropy change for water-splitting means far more excitation levels in the products. Consequently,
A low temperature (T°), thermal agitation allow mostly the water molecules to be excited as hydrogen and oxygen levels required higher thermal agitation to be significantly populated (on the arbitrary diagram, 3 levels can be populated for water vs 1 for the oxygen/hydrogen subsystem),
At high temperature (T), thermal agitation is sufficient for the oxygen/hydrogen subsystem excitation levels to be excited (on the arbitrary diagram, 4 levels can be populated for water vs 8 for the oxygen/hydrogen subsystem). According to the previous statements, the system will thus evolve toward the composition where most of its excitation levels are similar, i.e. a majority of oxygen and hydrogen species.
One can imagine that if T were high enough in Eq.(3), ΔG could be nullified, meaning that water-splitting would occur even without work (thermolysis of water). Though possible, this would require tremendously high temperatures: considering the same system naturally with steam instead of liquid water (ΔH° = 242 kJ/mol; ΔS° = 44 J/mol/K) would hence give required temperatures above 3000K, that make reactor design and operation extremely challenging.
Hence, a single reaction only offers one freedom degree (T) to produce hydrogen and oxygen only from heat (though using Le Chatelier's principle would also allow to slightly decrease the thermolysis temperature, work must be provided in this case for extracting the gas products from the system)
Water-splitting with multiple reactions
On the contrary, as shown by Funk and Reinstrom, multiple reactions (e.g. k steps) provide additional means to allow spontaneous water-splitting without work thanks to different entropy changes ΔS°i for each reaction i. An extra benefit compared with water thermolysis is that oxygen and hydrogen are separately produced, avoiding complex separations at high temperatures.
The first pre-requisites (Eqs.(4) and (5)) for multiple reactions i to be equivalent to water-splitting are trivial (cf. Hess's law):
(4)
(5)
Similarly, the work ΔG required by the process is the sum of each reaction work ΔGi:
(6)
As Eq. (3) is a general law, it can be used anew to develop each ΔGi term. If the reactions with positive (p indice) and negative (n indice) entropy changes are expressed as separate summations, this gives,
(7)
Using Eq. (6) for standard conditions allows to factorize the ΔG°i terms, yielding,
(8)
Now consider the contribution of each summation in Eq. (8): in order to minimize ΔG, they must be as negative as possible:
: -ΔS°i are negative, so (T-T°) must be as high as possible: hence, one choose to operate at the maximum process temperature TH
: -ΔS°i are positive, (T-T°) should be ideally negative in order to decrease ΔG. Practically, one can only set T equals to T° as the minimum process temperature in order to get rid of this troublesome term (a process requiring a lower than standard temperature for energy production is a physical absurdity as it would require refrigerators and thus a higher work input than output). Consequently, Eq.(8) becomes,
(9)
Finally, one can deduce from this last equation the relationship required for a null work requirement (ΔG ≤ 0)
(10)
Consequently, a thermochemical cycle with i steps can be defined as sequence of i reactions equivalent to water-splitting and satisfying equations (4), (5) and (10). The key point to remember in that case is that the process temperature TH can theoretically be arbitrary chosen (1000K as a reference in most of the past studies, for high temperature nuclear reactors), far below the water thermolysis one.
This equation can alternatively (and naturally) be derived via the Carnot's theorem, that must be respected by the system composed of a thermochemical process coupled with a work producing unit (chemical species are thus in a closed loop):
at least two heat sources of different temperatures are required for cyclical operation, otherwise perpetual motion would be possible. This is trivial in the case of thermolysis, as the fuel is consumed via an inverse reaction. Consequently, if there is only one temperature (the thermolysis one), maximum work recovery in a fuel cell is equal to the opposite of the Gibbs free energy of the water-splitting reaction at the same temperature, i.e. null by definition of the thermolysis. Or differently said, a fuel is defined by its instability, so if the water/hydrogen/oxygen system only exists as hydrogen and oxygen (equilibrium state), combustion (engine) or use in a fuel cell would not be possible.
endothermic reactions are chosen with positive entropy changes in order to be favored when the temperature increases, and the opposite for the exothermic reactions.
maximal heat-to-work efficiency is the one of a Carnot heat engine with the same process conditions, i.e. a hot heat source at TH and a cold one at T°,
(11)
the work output W is the "noble" energy stored in the hydrogen and oxygen products (e.g. released as electricity during fuel consumption in a fuel cell). It thus corresponds to the free Gibbs energy change of water-splitting ΔG, and is maximum according to Eq.(3) at the lowest temperature of the process (T°) where it is equal to ΔG°.
the heat input Q is the heat provided by the hot source at temperature TH to the i endothermic reactions of the thermochemical cycle (the fuel consumption subsystem is exothermic):
(12)
Hence, each heat requirement at temperature TH is,
(13)
Replacing Eq.(13) in Eq.(12) yields:
(14)
Consequently, replacing W (ΔG°) and Q (Eq.(14)) in Eq.(11) gives after reorganization Eq.(10) (assuming that the ΔSi do not change significantly with the temperature, i.e. are equal to ΔS°i)
Equation (10) has practical implications about the minimum number of reactions for such a process according to the maximum process temperature TH. Indeed, a numerical application (ΔG° equals to 229 kJ/K for water considered as steam) in the case of the originally chosen conditions (high-temperature nuclear reactor with TH and T° respectively equal to 1000K and 298K) gives a minimum value around 330 J/mol/K for the summation of the positive entropy changes ΔS°i of the process reactions.
This last value is very high as most of the reactions have entropy change values below 50 J/mol/K, and even an elevated one (e.g. water-splitting from liquid water: 163 J/mol/K) is twice lower. Consequently, thermochemical cycles composed of less than three steps are practically impossible with the originally planned heat sources (below 1000K), or require "hybrid" versions
Hybrid thermochemical cycles
In this case, an extra freedom degree is added via a relatively small work input Wadd (maximum work consumption, Eq.(9) with ΔG ≤ Wadd), and Eq.(10) becomes,
(15)
If Wadd is expressed as a fraction f of the process heat Q (Eq.(14)), Eq.(15) becomes after reorganization,
(16)
Using a work input equals to a fraction f of the heat input is equivalent relative to the choice of the reactions to operate a pure similar thermochemical cycle but with a hot source with a temperature increased by the same proportion f.
Naturally, this decreases the heat-to-work efficiency in the same proportion f. Consequently, if one want a process similar to a thermochemical cycle operating with a 2000K heat source (instead of 1000K), the maximum heat-to-work efficiency is twice lower. As real efficiencies are often significantly lower than ideal one, such a process is thus strongly limited.
Practically, use of work is restricted to key steps such as product separations, where techniques relying on work (e.g. electrolysis) might sometimes have fewer issues than those using only heat (e.g. distillations)
Particular case : Two-step thermochemical cycles
According to equation (10), the minimum required entropy change (right term) for the summation of the positive entropy changes decreases when TH increases. As an example, performing the same numerical application but with TH equals to 2000K would give a twice lower value (around 140 kJ/mol), which allows thermochemical cycles with only two reactions. Such processes can be realistically coupled with concentrated solar power technologies like Solar Updraft Tower. As an example in Europe, this is the goal of the Hydrosol-2 project (Greece, Germany (German Aerospace Center), Spain, Denmark, England) and of the researches of the solar department of the ETH Zurich and the Paul Scherrer Institute (Switzerland).
Examples of reactions satisfying high entropy changes are metal oxide dissociations, as the products have more excitation levels due to their gaseous state (metal vapors and oxygen) than the reactant (solid with crystalline structure, so symmetry dramatically reduces the number of different excitation levels). Consequently, these entropy changes can often be larger than the water-splitting one and thus a reaction with a negative entropy change is required in the thermochemical process so that Eq.(5) is satisfied. Furthermore, assuming similar stabilities of the reactant (ΔH°) for both thermolysis and oxide dissociation, a larger entropy change in the second case explained again a lower reaction temperature (Eq.(3)).
Let us assume two reactions, with positive (1 subscript, at TH) and negative (2 subscript, at T°) entropy changes. An extra property can be derived in order to have TH strictly lower than the thermolysis temperature: The standard thermodynamic values must be unevenly distributed among the reactions .
Indeed, according to the general equations (2) (spontaneous reaction), (4) and (5), one must satisfy,
(17)
Hence, if ΔH°1 is proportional to ΔH°2 by a given factor, and if ΔS°1 and ΔS°2 follow a similar law (same proportionality factor), the inequality (17) is broken (equality instead, so TH equals to the water thermolysis temperature).
Examples
Hundreds of such cycles have been proposed and investigated. This task has been eased by the availability of computers, allowing a systematic screening of chemical reactions sequences based on thermodynamic databases. Only the main "families" will be described in this article.
Two-step cycles
Two-step thermochemical cycles, often involving metal oxides, can be divided into two categories depending on the nature of the reaction: volatile and non-volatile. Volatile cycles utilize metal species that sublime during the reduction of the metal oxides, and non-volatile cycles can be further categorized into stoichiometric cycles and non-stoichiometric cycles. During the reduction half-cycle of the stochiometric cycle, the metal oxide is reduced and forms a new metal oxide with different oxidation states (Fe3O4 → 3FeO + 1/2 O2); a non-stochiometric cycle's reduction of the metal oxide will produce vacancies, often oxygen vacancies, but the crystal structure remains stable and only a portion of the metal atoms change their oxidation state (CeO2 → CeO2−δ + δ/2 O2).
Non-stoichiometric cycles with CeO2
The non-stoichiometric cycles with CeO2 can be describes with the following reactions:
Reduction reaction: CeO2 → CeO2−δ + δ/2 O2
Oxidation reaction: CeO2−δ + δ H2O → CeO2 + δ H2
The reduction occurs when CeO2, or ceria, is exposed to a inert atmosphere at around 1500 °C to 1600 °C, and hydrogen release occurs at 800 °C during hydrolysis when it is subjected to an atmosphere containing water vapor. One advantage of ceria over iron oxide lies in its higher melting point, which allows it to sustain higher temperature during reduction cycle. In addition, ceria's ionic conductivity allows oxygen atoms to diffuse through its structure several orders of magnitude faster than Fe ions can diffuse through iron oxide. Consequently, the redox reactions of ceria can occur at occur at a larger length scale, making it an ideal candidate for thermochemical reactor testing. Ceria-based thermochemical reactor has been created and tested as early as 2010, and viability of cycling was corroborated under realistic solar concentrating conditions. One disadvantage that limits ceria's application is its relatively lower oxygen storage capability.
Non-stoichiometric cycles with perovskite
The non-stoichiometric cycles with a perovskite ABO3 can be describes with the following reactions:
Reduction reaction: ABO3 → ABO3−δ + δ/2 O2
Oxidation reaction: ABO3−δ + δ H2O → ABO3 + δ H2
The reduction thermodynamics of perovskite makes it more favorable during the reduction half-cycle, during which more oxygen is produced; however, the oxidation thermodynamics proves less suitable, and sometimes perovskite is not completely oxidized. The two atomic sites, A and B, offer more doping possibilities and a much larger potential for different configurations.
Cycles with more than 3 steps and hybrid cycles
Cycles based on sulfur chemistry
Due to sulfur's high covalence, it can form up to 6 chemical bonds with other elements such as oxygen, resulting in a large number of oxidation states. Thus, there exist several redox reactions involving sulfur compounds. This freedom allows numerous chemical steps with different entropy changes, increasing the odds of meeting the criteria for a thermochemical cycle.
Much of the initial research was conducted in the United States, with sulfate- and sulfide-based cycles studied at Kentucky University, the Los Alamos National Laboratory and General Atomics. Significant research based on sulfates (e.g., FeSO4 and CuSO4) was conducted in Germany and Japan. The sulfur-iodine cycle, discovered by General Atomics, has been proposed as a way of supplying a hydrogen economy without the need for hydrocarbons.
Cycles based on the reversed Deacon process
Above 973K, the Deacon reaction is reversed, yielding hydrogen chloride and oxygen from water and chlorine:
H2O + Cl2 → 2 HCl + 1/2 O2
See also
Iron oxide cycle
Cerium(IV) oxide-cerium(III) oxide cycle
Copper-chlorine cycle
Hybrid sulfur cycle
Hydrosol-2
Sulfur-iodine cycle
Zinc zinc-oxide cycle
UT-3 cycle
References
Thermochemistry | Thermochemical cycle | Chemistry | 4,345 |
24,886,193 | https://en.wikipedia.org/wiki/Dispersion%20stability | Dispersions are unstable from the thermodynamic point of view; however, they can be kinetically stable over a large period of time, which determines their shelf life. This time span needs to be measured in order to ensure the best product quality to the final consumer.
“Dispersion stability refers to the ability of a dispersion to resist change in its properties over time.” D.J. McClements.
Destabilisation phenomena of a dispersion
These destabilisations can be classified into two major processes:
Migration phenomena : whereby the difference in density between the continuous and dispersed phase, leads to gravitational phase separation:
Creaming, when the dispersed phase is less dense than the continuous phase (e.g. milk, cosmetic cream, soft drinks, etc.)
Sedimentation, when the dispersed phase is denser than the continuous phase (e.g. ink, CMP slurries, paint, etc.)
Particle size increase phenomena: whereby the size of the dispersed phase (drops, particles, bubbles) increases
reversibly (flocculation)
irreversibly (aggregation, coalescence, Ostwald ripening)
Technique monitoring physical stability
Multiple light scattering coupled with vertical scanning is one of many techniques monitor the dispersion state of a product, identifying and quantifying destabilisation phenomena. It works on concentrated dispersions without dilution. When light is sent through the sample, it is backscattered by the particles / droplets. The backscattering intensity is directly proportional to the size and volume fraction of the dispersed phase. Therefore, local changes in concentration (creaming and sedimentation) and global changes in size (flocculation, coalescence) are detected and monitored.
Accelerating methods for shelf life prediction
The kinetic process of destabilisation can be rather long (up to several months or even years for some products) and it is often required for the formulator to use further accelerating methods in order to reach reasonable development time for new product design. Thermal methods are the most commonly used and consist in increasing temperature to accelerate destabilisation (below critical temperatures of phase inversion or chemical degradation). Temperature affects not only the viscosity, but also interfacial tension in the case of non-ionic surfactants or more generally interaction forces inside the system. Storing a dispersion at high temperatures may accelerate some instability processes.
Mechanical acceleration, including vibration, centrifugation, and agitation, can also be used.
References
Laboratory techniques | Dispersion stability | Chemistry | 516 |
32,516 | https://en.wikipedia.org/wiki/Vladimir%20Vernadsky | Vladimir Ivanovich Vernadsky, also spelt Volodymyr Ivanovych Vernadsky (; ; – 6 January 1945), was a Russian, Ukrainian, and Soviet mineralogist and geochemist who is considered one of the founders of geochemistry, biogeochemistry, and radiogeology. He was one of the founders and the first president of the Ukrainian Academy of Sciences (now National Academy of Sciences of Ukraine). Vladimir Vernadsky is most noted for his 1926 book The Biosphere in which he inadvertently worked to popularize Eduard Suess's 1875 term biosphere, by hypothesizing that life is the geological force that shapes the earth. In 1943 he was awarded the Stalin Prize. Vernadsky's portrait is depicted on the Ukrainian ₴1,000 hryvnia banknote.
Early life
Vernadsky was born in Saint Petersburg, Russian Empire, on in the family of the native Kyiv residents Russian Imperial economist Ivan Vernadsky and music instructor Anna Konstantinovich, who came from an old Russia noble family. According to family legend, his father's ancestors were Zaporozhian Cossacks. Ivan Vernadsky had been a professor of political economy in Kyiv at the St. Vladimir University before moving to Saint Petersburg; then he was an Active State Councillor and worked in the Governing Senate in St. Petersburg. Vladimir's mother was a Russian noblewoman of Ukrainian Cossack descent. In 1868 his family relocated to Kharkiv, and in 1873 he entered the Kharkiv provincial gymnasium.
Vernadsky graduated from Saint Petersburg State University in 1885. As the position of mineralogist in Saint Petersburg State University was vacant, and Vasily Dokuchaev, a soil scientist, and Alexey Pavlov, a geologist, had been teaching Mineralogy for a while, Vernadsky chose to enter Mineralogy. He wrote to his wife Nataliia on 20 June 1888 from Switzerland:
In 1888–1890, he traveled through Europe, studying the museums of Paris and London, and worked in Munich and Paris.
While trying to find a topic for his doctorate, he first went to Naples to study under crystallographer Arcangelo Scacchi, who was senile by that time. Scacchi's condition led Vernadsky to go to Germany to study under Paul Groth, curator of minerals in the Deutsches Museum in Munich. Vernadsky learned to use Groth's modern equipment, which included a machine to study the optical, thermal, elastic, magnetic and electrical properties of crystals. He also gained access to the physics lab of Leonhard Sohncke (Direktor, , 1883–1886; Professor der Physik an der Technischen Hochschule München 1886–1897), who was studying crystallisation during that period.
In his childhood, his father had a huge influence on his development, he very carefully and consistently engaged in the upbringing and education of his son. It was he who instilled in Volodymyr interest and love for the Ukrainian people, their history and culture. The future scientist recalled that before moving from Kharkiv to St. Petersburg, he and his father were abroad and in Milan, they read about a circular in Pyotr Lavrov's newspaper "Forward" that forbade printing in Ukrainian in Russia. In his memoirs, he wrote:
In St. Petersburg, a 15-year-old boy noted in his diary on 29 March 1878:
Political activities
Vernadsky participated in the First General Congress of the zemstvos, held in Petersburg on the eve of the 1905 Russian Revolution to discuss how best to pressure the government to the needs of the Russian society; became a member of the liberal Constitutional Democratic Party (KD); and served in parliament, resigning to protest the Tsar's proroguing of the Duma. He served as professor and later as vice rector of Moscow University, from which he also resigned in 1911 in protest over the government's reactionary policies .
Following the advent of the First World War, his proposal for the establishment of the Commission for the Study of the Natural Productive Forces (KEPS) was adopted by the Imperial Academy of Sciences in February 1915. He published War and the Progress of Science where he stressed the importance of science as regards to its contribution to the war effort:
After the war of 1914–1915 we will have to make known and accountable the natural productive forces of our country, i.e. first of all to find means for broad scientific investigations of Russia’s nature and for the establishment of a network of well equipped research laboratories, museums and institutions ... This is no less necessary than the need for an improvement in the conditions of our civil and political life, which is so acutely perceived by the entire country.
After the February Revolution of 1917, he served on several commissions of agriculture and education of the provisional government, including as assistant minister of education.
Vladimir Vernadsky had dual "Russian–Ukrainian" identity and considered the Ukrainian culture as part of Russian imperial culture, and even declined to become a Ukrainian citizen in 1918.
Scientific activities
Vernadsky first popularized the concept of the noosphere and deepened the idea of the biosphere to the meaning largely recognized by today's scientific community. The word 'biosphere' was invented by Austrian geologist Eduard Suess, whom Vernadsky met in 1911.
In Vernadsky's theory of the Earth's development, the noosphere is the third stage in the earth's development, after the geosphere (inanimate matter) and the biosphere (biological life). Just as the emergence of life fundamentally transformed the geosphere, the emergence of human cognition will fundamentally transform the biosphere. In this theory, the principles of both life and cognition are essential features of the Earth's evolution, and must have been implicit in the earth all along. This systemic and geological analysis of living systems complements Charles Darwin's theory of natural selection, which looks at each individual species, rather than at its relationship to a subsuming principle.
Vernadsky's visionary pronouncements were not widely accepted in the West. However, he was one of the first scientists to recognize that the oxygen, nitrogen and carbon dioxide in the Earth's atmosphere result from biological processes. During the 1920s he published works arguing that living organisms could reshape the planets as surely as any physical force. Vernadsky was an important pioneer of the scientific bases for the environmental sciences.
Vernadsky was a member of the Russian and Soviet Academies of Sciences since 1912 and was a founder and first president of the Ukrainian Academy of Sciences in Kyiv, Ukraine (1918). He was a founder of the National Library of Ukrainian State and worked closely with the Tavrida University in Crimea. During the Russian Civil War, he hosted gatherings of the young intellectuals who later founded the émigré Eurasianism movement.
In the late 1930s and early 1940s Vernadsky played an early advisory role in the Soviet atomic bomb project, as one of the most forceful voices arguing for the exploitation of nuclear power, the surveying of Soviet uranium sources, and having nuclear fission research conducted at his Radium Institute. He died, however, before a full project was pursued.
On religious views, Vernadsky was an atheist. He was interested in Hinduism and Rig Veda.
Vernadsky's son George Vernadsky (1887–1973) emigrated to the United States where he published numerous books on medieval and modern Russian history.
The National Library of Ukraine, the Tavrida National University in Crimea and many streets and avenues in Ukraine and Russia are named in honor of Vladimir Vernadsky.
UNESCO sponsored an international scientific conference, "Globalistics-2013", at Moscow State University on 23–25 October 2013, in honor of Vernadsky's 150th birthday.
Family
Father – Ivan Vernadsky, Russian Imperial economist
Mother – Аnna Konstantinovich, Russian music instructor
Wife – Nataliia Yegorovna Staritskaya (married in 1887 in Saint Petersburg)
Son – George Vernadsky, American Russian historian, an author of numerous books on Russian history and philosophy
Daughter – Nina Toll, Doctor-psychiatrist
Legacy
Vernadsky National Library of Ukraine is the main academic library in Ukraine
Ukrainian Antarctic station Akademik Vernadsky
Tavrida National V.I. Vernadsky University, university in Simferopol
Vernadsky Institute of Geochemistry and Analytical Chemistry, a research institution of the Russian Academy of Sciences
Vernadsky State Geological Museum is the oldest museum in Moscow
Vernadsky Mountain Range is a mountains in Antarctica and is an extension of the Gamburtsev Mountain Range.
Several avenues in major cities in the former USSR, including Kyiv, Moscow and his native Saint Petersburg, bear his name.
Vernadskiy (crater), a lunar crater
Vernadsky Medal awarded annually by the International Association of GeoChemistry
2809 Vernadskij, an asteroid
On 25 October 2019 the National Bank of Ukraine put in circulation a ₴1,000 hryvnia banknote with Vernadsky's portrait.
Selected works
Geochemistry, published in Russian 1924
The Biosphere, first published in Russian in 1926. English translations:
Oracle, AZ, Synergetic Press, 1986, , 86 pp.
tr. David B. Langmuir, ed. Mark A. S. McMenamin, New York, Copernicus, 1997, , 192 pp.
Essays on Geochemistry & the Biosphere, tr. Olga Barash, Santa Fe, NM, Synergetic Press, , 2006
Diaries
Dnevniki 1917–1921: oktyabr 1917-yanvar 1920 (Diaries 1917–1921), Kyiv, Naukova dumka, 1994, , 269 pp.
Dnevniki. Mart 1921-avgust 1925 (Diaries 1921–1925), Moscow, Nauka, 1998, , 213 pp.
Dnevniki 1926–1934 (Diaries 1926–1934), Moscow, Nauka, 2001, , 455 pp.
Dnevniki 1935–1941 v dvukh knigakh. Kniga 1, 1935–1938 (Diaries 1935–1941 in two volumes. Volume 1, 1935–1938), Moscow, Nauka, 2006, ,444 pp.
Dnevniki 1935–1941 v dvukh knigakh. Kniga 2, 1939–1941 (Diaries 1935–1941. Volume 2, 1939–1941), Moscow, Nauka, 2006, , 295 pp.
See also
Gaia theory (science)
Noosphere
Pierre Teilhard de Chardin
Prospekt Vernadskogo District
Russian philosophy
References
Bibliography
"Science and Russian Cultures in an Age of Revolutions"
External links
The grave of Vernadsky
Behrends, Thilo, The Renaissance of V.I. Vernadsky, Newsletter of the Geochemical Society, #125, October 2005, retrieved 4 May 2024
Vernadsky's biography
Electronic archive of writings from and about Vernadsky (Russian) Электронный Архив В. И. Вернадского
1863 births
1945 deaths
Scientists from Saint Petersburg
People from Sankt-Peterburgsky Uyezd
Russian people of Ukrainian descent
Presidents of the National Academy of Sciences of Ukraine
Russian Constitutional Democratic Party members
Members of the State Council (Russian Empire)
Cosmists
Soviet geochemists
Ukrainian geochemists
Russian geochemists
Philosophers from the Russian Empire
Full members of the Saint Petersburg Academy of Sciences
Full Members of the Russian Academy of Sciences (1917–1925)
Full Members of the USSR Academy of Sciences
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Ukrainian philosophers
Russian atheists
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Mineralogists from the Russian Empire
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Recipients of the Order of the Red Banner of Labour
Recipients of the Order of Saint Stanislaus (Russian), 2nd class
Recipients of the Order of St. Anna, 2nd class
Russian expatriates in Ukraine
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Privy Councillor (Russian Empire)
Burials at Novodevichy Cemetery
Untitled nobility from the Russian Empire
Geologists from the Russian Empire | Vladimir Vernadsky | Chemistry | 2,543 |
56,511,240 | https://en.wikipedia.org/wiki/Pseudo-marginal%20Metropolis%E2%80%93Hastings%20algorithm | In computational statistics, the pseudo-marginal Metropolis–Hastings algorithm is a Monte Carlo method to sample from a probability distribution. It is an instance of the popular Metropolis–Hastings algorithm that extends its use to cases where the target density is not available analytically. It relies on the fact that the Metropolis–Hastings algorithm can still sample from the correct target distribution if the target density in the acceptance ratio is replaced by an estimate. It is especially popular in Bayesian statistics, where it is applied if the likelihood function is not tractable (see example below).
Algorithm description
The aim is to simulate from some probability density function . The algorithm follows the same steps as the standard Metropolis–Hastings algorithm except that the evaluation of the target density is replaced by a non-negative and unbiased estimate. For comparison, the main steps of a Metropolis–Hastings algorithm are outlined below.
Metropolis–Hastings algorithm
Given a current state the Metropolis–Hastings algorithm proposes a new state according to some density . The algorithm then sets with probability
otherwise the old state is kept, that is, .
Pseudo-marginal Metropolis–Hastings algorithm
If the density is not available analytically the above algorithm cannot be employed. The pseudo-marginal Metropolis–Hastings algorithm in contrast only assumes the existence of an unbiased estimator , i.e. the estimator must satisfy the equation Now, given and the respective estimate the algorithm proposes a new state according to some density . Next, compute an estimate and set with probability
otherwise the old state is kept, that is, .
Application to Bayesian statistics
In Bayesian statistics the target of inference is the posterior distribution
where denotes the likelihood function, is the prior and is the prior predictive distribution.
Since there is often no analytic expression of this quantity, one often relies on Monte Carlo methods to sample from the distribution instead. Monte Carlo methods often need the likelihood to be accessible for every parameter value . In some cases, however, the likelihood does not have an analytic expression. An example of such a case is outlined below.
Example: Latent variable model
Consider a model consisting of i.i.d. latent real-valued random variables with and suppose one can only observe these variables through some additional noise for some conditional density . (This could be due to measurement error, for instance.) We are interested in Bayesian analysis of this model based on some observed data . Therefore, we introduce some prior distribution on the parameter. In order to compute the posterior distribution
we need to find the likelihood function . The likelihood contribution of any observed data point is then
and the joint likelihood of the observed data is
If the integral on the right-hand side is not analytically available, importance sampling can be used to estimate the likelihood. Introduce an auxiliary distribution such that for all then
is an unbiased estimator of and the joint likelihood can be estimated unbiasedly by
Extensions
Pseudo-marginal Metropolis-Hastings can be seen as a special case of so-called particle marginal Metropolis-Hastings algorithms. In the case of the latter, unbiased estimators of densities relating to static parameters in state-space models may be obtained using a particle filter. While the algorithm enables inference on both the joint space of static parameters and latent variables, when interest is only in the static parameters the algorithm is equivalent to a pseudo-marginal algorithm.
References
Monte Carlo methods
Statistical algorithms | Pseudo-marginal Metropolis–Hastings algorithm | Physics | 681 |
21,053,298 | https://en.wikipedia.org/wiki/Diphtheria%20vaccine | Diphtheria vaccine is a toxoid vaccine against diphtheria, an illness caused by Corynebacterium diphtheriae. Its use has resulted in a more than 90% decrease in number of cases globally between 1980 and 2000. The first dose is recommended at six weeks of age with two additional doses four weeks apart, after which it is about 95% effective during childhood. Three further doses are recommended during childhood. It is unclear if further doses later in life are needed.
The diphtheria vaccine is very safe. Significant side effects are rare. Pain may occur at the injection site. A bump may form at the site of injection that lasts a few weeks. The vaccine is safe in both pregnancy and among those who have a poor immune function.
The diphtheria vaccine is delivered in several combinations. Some combinations (Td and DT vaccines) include tetanus vaccine, others (known as DPT vaccine or DTaP vaccine depending on the pertussis antigen used) comes with the tetanus and pertussis vaccines, and still others include additional vaccines such as Hib vaccine, hepatitis B vaccine, or inactivated polio vaccine. The World Health Organization (WHO) has recommended its use since 1974. About 84% of the world population is vaccinated. It is given as an intramuscular injection. The vaccine needs to be kept cold but not frozen.
The diphtheria vaccine was developed in 1923. It is on the World Health Organization's List of Essential Medicines.
History
In 1890, Kitasato Shibasaburō and Emil von Behring at the University of Berlin reported the development of 'antitoxins' against diphtheria and tetanus. Their method involved injecting the respective toxins into animals and then purifying antibodies from their blood. Behring called this method 'serum therapy'. While effective against the pathogen, initial tests on humans were unsuccessful. By 1894, the production of antibodies had been optimised with help from Paul Ehrlich, and the treatment started to show success in humans. The serum therapy reduced mortality to 1–5%, although there were also reports of severe adverse reactions, including at least one death. Behring won the very first Nobel Prize in Physiology or Medicine for this discovery. Kitasato, however, was not awarded.
By 1913, Behring had created Antitoxin-Toxin (antibody-antigen) complexes to produce the diphtheria AT vaccine. In the 1920s, Gaston Ramon developed a cheaper version by using formaldehyde-inactivated toxins. As the use of these vaccines spread across the world, the number of diphtheria cases was greatly reduced. In the United States alone, the number of cases fell from 100,000 to 200,000 per year in the 1920s to 19,000 in 1945 and 14 in the period 1996–2018.
Effectiveness
About 95% of people vaccinated develop immunity, and vaccination against diphtheria has resulted in a more than 90% decrease in number of cases globally between 1980 and 2000. About 86% of the world population was vaccinated as of 2016.
Side effects
Severe side effects from diphtheria toxoid are rare. Pain may occur at the injection site. A bump may form at the site of injection that lasts a few weeks. The vaccine is safe during pregnancy and among those who have a poor immune function. DTP vaccines may cause additional adverse effects such as fever, irritability, drowsiness, loss of appetite, and, in 6–13% of vaccine recipients, vomiting. Severe adverse effects of DTP vaccines include fever over 40.5 °C/104.9 °F (1 in 333 doses), febrile seizures (1 in 12,500 doses), and hypotonic-hyporesponsive episodes (1 in 1,750 doses). Side effects of DTaP vaccines are similar but less frequent. Tetanus toxoid containing vaccines (Td, DT, DTP and DTaP) may cause brachial neuritis at a rate of 0.5 to 1 case per 100,000 toxoid recipients.
Recommendations
The World Health Organization has recommended vaccination against diphtheria since 1974. The first dose is recommended at six weeks of age with two additional doses four weeks apart, after receiving these three doses about 95% of people are immune. Three further doses are recommended during childhood. Booster doses every ten years are no longer recommended if this vaccination scheme of 3 doses + 3 booster doses is followed. Injection of 3 doses + 1 booster dose, provides immunity for 25 years after the last dose. If only three initial doses are given, booster doses are needed to ensure continuing protection.
See also
Bundaberg tragedy
DTP-HepB vaccine
References
Further reading
External links
Vaccine
1923 in biology
Toxoid vaccines
Vaccines
World Health Organization essential medicines (vaccines)
Wikipedia medicine articles ready to translate | Diphtheria vaccine | Biology | 1,018 |
1,830,232 | https://en.wikipedia.org/wiki/Iterative%20closest%20point | Iterative closest point (ICP) is a point cloud registration algorithm employed to minimize the difference between two clouds of points. ICP is often used to reconstruct 2D or 3D surfaces from different scans, to localize robots and achieve optimal path planning (especially when wheel odometry is unreliable due to slippery terrain), to co-register bone models, etc.
Overview
The Iterative Closest Point algorithm keeps one point cloud, the reference or target, fixed, while transforming the other, the source, to best match the reference. The transformation (combination of translation and rotation) is iteratively estimated in order to minimize an error metric, typically the sum of squared differences between the coordinates of the matched pairs. ICP is one of the widely used algorithms in aligning three dimensional models given an initial guess of the rigid transformation required.
The ICP algorithm was first introduced by Chen and Medioni, and Besl and McKay.
Inputs: reference and source point clouds, initial estimation of the transformation to align the source to the reference (optional), criteria for stopping the iterations.
Output: refined transformation.
Essentially, the algorithm steps are:
For each point (from the whole set of vertices usually referred to as dense or a selection of pairs of vertices from each model) in the source point cloud, match the closest point in the reference point cloud (or a selected set).
Estimate the combination of rotation and translation using a root mean square point-to-point distance metric minimization technique which will best align each source point to its match found in the previous step. This step may also involve weighting points and rejecting outliers prior to alignment.
Transform the source points using the obtained transformation.
Iterate (re-associate the points, and so on).
Zhang proposes a modified k-d tree algorithm for efficient closest point computation. In this work a statistical method based on the distance distribution is used to deal with outliers, occlusion, appearance, and disappearance, which enables subset-subset matching.
There exist many ICP variants, from which point-to-point and point-to-plane are the most popular. The latter usually performs better in structured environments.
Implementations
MeshLab an open source mesh processing tool that includes a GNU General Public License implementation of the ICP algorithm.
CloudCompare an open source point and model processing tool that includes an implementation of the ICP algorithm. Released under the GNU General Public License.
PCL (Point Cloud Library) is an open-source framework for n-dimensional point clouds and 3D geometry processing. It includes several variants of the ICP algorithm.
Open source C++ implementations of the ICP algorithm are available in VTK, ITK and Open3D libraries.
libpointmatcher is an implementation of point-to-point and point-to-plane ICP released under a BSD license.
simpleICP is an implementation of a rather simple version of the ICP algorithm in various languages.
See also
Normal distributions transform
References
Geometry in computer vision
Robot navigation | Iterative closest point | Mathematics | 618 |
623,112 | https://en.wikipedia.org/wiki/Robotic%20mapping | Robotic mapping is a discipline related to computer vision and cartography. The goal for an autonomous robot is to be able to construct (or use) a map (outdoor use) or floor plan (indoor use) and to localize itself and its recharging bases or beacons in it. Robotic mapping is that branch which deals with the study and application of ability to localize itself in a map / plan and sometimes to
construct the map or floor plan by the autonomous robot.
Evolutionarily shaped blind action may suffice to keep some animals alive. For some insects for example, the environment is not interpreted as a map, and they survive only with a triggered response. A slightly more elaborated navigation strategy dramatically enhances the capabilities of the robot. Cognitive maps enable planning capacities and use of current perceptions, memorized events, and expected consequences.
Operation
The robot has two sources of information: the idiothetic and the allothetic sources. When in motion, a robot can use dead reckoning methods such as tracking the number of revolutions of its wheels; this corresponds to the idiothetic source and can give the absolute position of the robot, but it is subject to cumulative error which can grow quickly.
The allothetic source corresponds the sensors of the robot, like a camera, a microphone, laser, lidar or sonar. The problem here is "perceptual aliasing". This means that two different places can be perceived as the same. For example, in a building, it is nearly impossible to determine a location solely with the visual information, because all the corridors may look the same. 3-dimensional models of a robot's environment can be generated using range imaging sensors or 3D scanners.
Map representation
The internal representation of the map can be "metric" or "topological":
The metric framework is the most common for humans and considers a two-dimensional space in which it places the objects. The objects are placed with precise coordinates. This representation is very useful, but is sensitive to noise and it is difficult to calculate the distances precisely.
The topological framework only considers places and relations between them. Often, the distances between places are stored. The map is then a graph, in which the nodes corresponds to places and arcs correspond to the paths.
Many techniques use probabilistic representations of the map, in order to handle uncertainty.
There are three main methods of map representations, i.e., free space maps, object maps, and composite maps. These employ the notion of a grid, but permit the resolution of the grid to vary so that it can become finer where more accuracy is needed and more coarse where the map is uniform.
Map learning
Map learning cannot be separated from the localization process, and a difficulty arises when errors in localization are incorporated into the map. This problem is commonly referred to as Simultaneous localization and mapping (SLAM).
An important additional problem is to determine whether the robot is in a part of environment already stored or never visited. One way to solve this problem is by using electric beacons, Near field communication (NFC), WiFi, Visible light communication (VLC) and Li-Fi and Bluetooth.
Path planning
Path planning is an important issue as it allows a robot to get from point A to point B. Path planning algorithms are measured by their computational complexity. The feasibility of real-time motion planning is dependent on the accuracy of the map (or floorplan), on robot localization and on the number of obstacles. Topologically, the problem of path planning is related to the shortest path problem of finding a route between two nodes in a graph.
Robot navigation
Outdoor robots can use GPS in a similar way to automotive navigation systems.
Alternative systems can be used with floor plan and beacons instead of maps for indoor robots, combined with localization wireless hardware. Electric beacons can help for cheap robot navigational systems.
See also
Automotive navigation system
Domestic robot
AVM Navigator
Dead reckoning
Electric beacon
GPS
Home automation for the elderly and disabled
Internet of Things (IoT)
Indoor positioning system
Map database management
Maze Simulator
Mobile robot
Neato Robotics
PatrolBot
Real-time locating system (RTLS).
Robotics suite
Occupancy grid
Simultaneous localization and mapping (SLAM)
Multi Autonomous Ground-robotic International Challenge: A challenge requiring multiple vehicles to collaboratively map a large dynamic urban environment
Wayfinding
Wi-Fi positioning system (WPS)
References
Cartography
Indoor positioning system | Robotic mapping | Technology | 897 |
72,300,019 | https://en.wikipedia.org/wiki/Revenge%20buying | Revenge buying (also known as revenge shopping or revenge spending) refers to a sudden surge in the purchase of consumer goods after people are denied the opportunity to shop for extended periods of time. The revenge buying mechanism is thought to have evolved as a reaction to the frustration and psychological discomfort caused by restrictions in the freedom of movement and commerce. Unlike panic buying, revenge buying appears to involve the purchase of superfluous goods, such as bags and clothing, as well as decorative objects such as gems and jewellery. The industries revolving around the production of these objects, a major source of revenue for the retail sector, saw huge losses during the lockdowns induced by the COVID-19 pandemic.
Revenge buying began in China initially, and the trends were seen across the globe when economies reopened. The United States and Europe followed the same kind of enthusiasm in consumers, and luxury brands posted remarkable growth compared to during COVID lockdowns.
Examples
In China, the Cultural Revolution during the 1960s and COVID-19 crisis nearly sixty years later are examples of collective traumas that resulted in revenge buying. The phenomenon was first observed in the 1980s, where it was termed baofuxing xiaofei (). Following China's 1976 opening to international trade, this term describes the sudden demand for foreign-brand goods. It reoccurred in China in April 2020, when the lockdown was mostly lifted and markets reopened. At that time, the French luxury brand Hermès made US$2.7 million in sales in a single day.
COVID-19 pandemic
The economic impact of the COVID-19 pandemic was devastating to many global retail businesses. Many stores and shopping centers were forced to close for months because stay-at-home restrictions meant that consumers could not travel freely. According to a March 2020 article in Business Insider, retail sales dropped 20.5 percent after the pandemic hit China—a percentage not seen since the 2007–2008 financial crisis.
The apparel industry suffered greatly during the pandemic; several notable retailers, including J. Crew, Neiman Marcus, J.C. Penney, Brooks Brothers, Ascena Retail Group, Debenhams, Arcadia Group, GNC, and Lord & Taylor, filed for bankruptcy.
China was the first country hit by the COVID-19 pandemic; by the summer 2020, it had successfully contained community transmission and thereafter lifted significant restrictions. The term revenge buying entered popular consciousness with the immediate economic recovery of the French fashion company Hermès, which recorded $2.7 million in sales at its flagship store in Guangzhou, China, on the day it reopened in April 2020, setting a record for most single-day shopping at any luxury outlet in China. In addition to Hermès, lines piled up outside Apple, Gucci, and Lancôme stores. A similar instance of revenge buying occurred in India following the relaxation of Omicron-related restrictions in March 2022. A similar level of consumer enthusiasm was observed by the press in the United States and Europe after their economies mostly reopened in April 2021.
Explanation
According to sociologists, compulsive and impulsive buying behaviors, such as panic buying and revenge buying, are coping mechanisms that relieve negative feelings.
While revenge buying was first observed in China, it has since been observed in other countries. When physical stores reopened after the initial COVID lockdown, sales increased, particularly in luxury product stores. According to researchers for the International Journal of Social Psychiatry, the purchase of luxury goods acts as a means for consumers to repress unpleasant emotions. Reactance theory is another analytical method sociologists use to gain a deeper understanding of revenge-buying behavior; this theory posits that when a threat or hindrance to a person's behavioral freedom makes them upset, the person will try to regain the threatened autonomy.
See also
Economic bubble
Panic selling
Consumer behaviour
2021 global inflation surge
References
Further reading
Consumer behaviour | Revenge buying | Biology | 795 |
14,581,969 | https://en.wikipedia.org/wiki/Lamport%27s%20distributed%20mutual%20exclusion%20algorithm | Lamport's Distributed Mutual Exclusion Algorithm is a contention-based algorithm for mutual exclusion on a distributed system.
Algorithm
Nodal properties
Every process maintains a queue of pending requests for entering critical section in order. The queues are ordered by virtual time stamps derived from Lamport timestamps.
Algorithm
Requesting process
Pushing its request in its own queue (ordered by time stamps)
Sending a request to every node.
Waiting for replies from all other nodes.
If own request is at the head of its queue and all replies have been received, enter critical section.
Upon exiting the critical section, remove its request from the queue and send a release message to every process.
Other processes
After receiving a request, pushing the request in its own request queue (ordered by time stamps) and reply with a time stamp.
After receiving release message, remove the corresponding request from its own request queue.
Message complexity
This algorithm creates 3(N − 1) messages per request, or (N − 1) messages and 2 broadcasts. 3(N − 1) messages per request includes:
(N − 1) total number of requests
(N − 1) total number of replies
(N − 1) total number of releases
Drawbacks
This algorithm has several disadvantages. They are:
It is very unreliable as failure of any one of the processes will halt progress.
It has a high message complexity of 3(N − 1) messages per entry/exit into the critical section.
See also
Ricart–Agrawala algorithm (an improvement over Lamport's algorithm)
Lamport's bakery algorithm
Raymond's algorithm
Maekawa's algorithm
Suzuki–Kasami algorithm
Naimi–Trehel algorithm
References
Concurrency control algorithms
Distributed computing | Lamport's distributed mutual exclusion algorithm | Technology | 342 |
1,631,654 | https://en.wikipedia.org/wiki/List%20of%20mathematical%20identities | This article lists mathematical identities, that is, identically true relations holding in mathematics.
Bézout's identity (despite its usual name, it is not, properly speaking, an identity)
Binet-cauchy identity
Binomial inverse theorem
Binomial identity
Brahmagupta–Fibonacci two-square identity
Candido's identity
Cassini and Catalan identities
Degen's eight-square identity
Difference of two squares
Euler's four-square identity
Euler's identity
Fibonacci's identity see Brahmagupta–Fibonacci identity or Cassini and Catalan identities
Heine's identity
Hermite's identity
Lagrange's identity
Lagrange's trigonometric identities
List of logarithmic identities
MacWilliams identity
Matrix determinant lemma
Newton's identity
Parseval's identity
Pfister's sixteen-square identity
Sherman–Morrison formula
Sophie Germain identity
Sun's curious identity
Sylvester's determinant identity
Vandermonde's identity
Woodbury matrix identity
Identities for classes of functions
Exterior calculus identities
Fibonacci identities: Combinatorial Fibonacci identities and Other Fibonacci identities
Hypergeometric function identities
List of integrals of logarithmic functions
List of topics related to
List of trigonometric identities
Inverse trigonometric functions
Logarithmic identities
Summation identities
Vector calculus identities
See also
External links
A Collection of Algebraic Identities
Matrix Identities
Identities | List of mathematical identities | Mathematics | 304 |
48,000,586 | https://en.wikipedia.org/wiki/Vernier%20spectroscopy | Vernier spectroscopy is a type of cavity enhanced laser absorption spectroscopy that is especially sensitive to trace gases. The method uses a frequency comb laser combined with a high finesse optical cavity to produce an absorption spectrum in a highly parallel manner. The method is also capable of detecting trace gases in very low concentration due to the enhancement effect of the optical resonator on the effective optical path length.
Overview of method
Understanding of the principle of operation of Vernier spectroscopy requires an understanding of frequency comb lasers. The oscillating electric field of a laser (or any time dependent signal) can be represented by a sum of sinusoidal signals in the frequency domain using the Fourier series. The oscillating electric field of a coherent, continuous-wave (cw) laser is represented as a single narrow peak in the frequency domain representation. If the laser is amplitude-modulated to produce a stable train of very short pulses (usually through mode-locking), the equivalent frequency domain representation is a series of narrow frequency peaks centered around the laser's original cw frequency. These frequency peaks are separated by the frequency of the time domain pulses. This is called the repetition rate of the frequency comb.
Since the sensitivity of absorption spectroscopy depends on the path length of the light in the test sample, cavity enhanced spectroscopy attains high sensitivity by creating multiple passes through the sample, effectively multiplying the path length. Vernier spectroscopy uses a high finesse cavity to produce a large enhancement. A high finesse optical cavity will also produce a sharp resonance condition, where only light that is coupled into it with frequencies coinciding with a harmonic of the free spectral range of the cavity will produce constructive interference and an appreciable output of the cavity.
There will only be appreciable output from the optical resonator when a frequency peak from the frequency-comb laser coincides with a harmonic of the free spectral range of the cavity. In Vernier spectroscopy, the ratio of the repetition rate of the frequency comb to the free spectral range of the cavity is N/(N-1), where N is an integer, so that only every N peak of the frequency comb will satisfy the resonance condition of the optical cavity and propagate through it and the sample. This is chosen so that the two sets of resonances form a Vernier scale, giving the name to the technique. This is essential because a typical frequency comb repetition rate is on the order of radio frequencies, making the task of resolving and detecting individual frequency components difficult. If N is made to be large, then the frequency separation of the resonator output peaks will be large enough to be resolved by a simple grating spectrometer. If the length of the cavity is changed slightly, usually by a piezoelectric actuator, then the free spectral range of the cavity will also change. This changing FSR develops a new set of resonances with the frequency comb as the scan proceeds, effectively scanning through the sets of 'filtered out' peaks of the frequency comb.
The individual frequency components of the transmitted light are spatially separated using a simple spectrometer, usually a diffraction grating. In order to achieve a highly parallel measurement of the individual frequency components transmitted through the sample and out of the cavity, a CCD camera capable of operating in the spectral range of the laser light is used. In the case of the diffraction grating, the frequency components are separated in one spatial direction and focused into the CCD camera. In order to take advantage of the other spatial direction of the CCD, the light is scanned across the perpendicular direction of the CCD at the same time that the cavity length is scanned using an actuator. This produces a grid of peaks on the CCD image corresponding to a mode matching condition between the frequency comb and optical cavity.
Example apparatus
A simple realization of the Vernier spectroscopy setup has five basic components: a frequency comb, a scannable high finesse optical cavity, a diffraction grating, rotating mirror, and a CCD camera. The trace gas to be measured is put between the mirrors of the optical cavity to allow for optical path enhancement. The frequency comb is coupled into the resonator and made to form a Vernier ratio with the response function. The output of the cavity is reflected off a diffraction grating, providing angular separation of the frequency components of the beam. The diffracted beam is then reflected off the rotatable mirror and then focused onto the CCD camera. Three things must then happen in synchronization. The optical cavity scans through a free spectral range of the cavity while the rotating mirror simultaneously scans the direction perpendicular to the diffraction grating's diffraction plane. These two actions can be synchronized by means of a periodic ramp voltage which controls both the cavity scan (accomplished by a piezoelectric actuator) and mirror rotation (controlled by a stepper motor). If the CCD camera's exposure time is also set equal to the ramp voltage period, the resulting CCD image is a two dimensional matrix of approximately Gaussian peaks. In this manner, an entire spectrum is produced in the period of the ramp voltage. The time it takes to obtain a spectrum is limited by the cavity scan time, rotating mirror response, and minimum camera exposure time. This particular Vernier spectroscopy scheme is capable of producing an absorption spectrum of a trace gas (<1 ppmV) with tens of thousands of data points in less than a second.
Vernier spectroscopy produces a kind of 2-dimensional spectral pattern on the CCD image, a matrix of approximately Gaussian peaks. The integrated intensity of each Gaussian peak gives the transmitted intensity through the test gas, while the position of the peak also gives information about the relative frequency of the peak. Additional information about the phase shift of the light transmitted by the test gas can be extracted from the shape of the individual peaks present on the image. Although all of the spectral information is contained in the images produced by the CCD, some amount of image processing is required to convert the CCD image into a traditional one-dimensional spectrum
References
Absorption spectroscopy | Vernier spectroscopy | Physics,Chemistry | 1,253 |
77,750,672 | https://en.wikipedia.org/wiki/List%20of%20O-type%20stars | This is a list of O-type stars by their distance from Earth.
List
Milky Way galaxy
Magellanic Clouds
The Large Magellanic Cloud (LMC) is around 163 kly distant and the Small Magellanic Cloud (SMC) is around 204 kly distant
Andromeda Galaxy and Triangulum Galaxy
The Andromeda Galaxy (M31) is 2.5 Mly distant and the Triangulum Galaxy is around 3.2 Mly distant
Other Galaxies
See also
List of Wolf-Rayet stars
List of luminous blue variable stars
List of nearest stars by spectral type
References
Lists of stars
Star systems
Lists by distance | List of O-type stars | Physics,Astronomy | 130 |
18,687,255 | https://en.wikipedia.org/wiki/JNJ-7777120 | JNJ-7777120 was a drug being developed by Johnson & Johnson Pharmaceutical Research & Development which acts as a potent and selective antagonist at the histamine H4 receptor. It has anti-inflammatory effects, and has been demonstrated to be superior to traditional (H1) antihistamines in the treatment of pruritus (itching). The drug was abandoned because of its short in vivo half-life and hypoadrenocorticism toxicity in rats and dogs, that prevented advancing it into clinical studies.
See also
VUF-6002
References
Carboxamides
Chloroarenes
H4 receptor antagonists
Indoles
Drugs developed by Johnson & Johnson
4-Methylpiperazin-1-yl compounds
Abandoned drugs | JNJ-7777120 | Chemistry | 157 |
43,456,340 | https://en.wikipedia.org/wiki/John%20Fritz | John F. Fritz (August 21, 1822 – February 13, 1913) was an American pioneer of iron and steel technology who has been referred to as the "Father of the U.S. Steel Industry". To celebrate his 80th birthday the John Fritz Medal was established in 1902, with Fritz himself being the first recipient.
Early life and education
Fritz was born August 21, 1822, in Londonderry Township, Chester County, Pennsylvania, the eldest of seven children of George Fritz and Mary Meharg. He was of German and Scotch-Irish descent.
Career
At the age of 16, Fritz was awarded an apprentiship as a blacksmith. He progressed to become a mechanic, working for the Norristown Iron Company. In 1854, he moved to the Cambria Iron Company, where he designed the first three-high rolling mill, a notable achievement. In 1860 he became General Superintendent and Chief Engineer of the Bethlehem Iron Works in Bethlehem, Pennsylvania. While there he was responsible for installing a Bessemer Converter and various developments in the company, staying until 1892, when he was 70.
Fritz was president of the American Society of Mechanical Engineers, president of the American Institute of Mining Engineers, honorary vice president for life of the Iron and Steel Institute of London, member of the American Society of Civil Engineers, honorary member of the American Iron and Steel Institute, and recipient of the Bessemer Gold Medal, the Elliott Cresson Gold Medal, and the John Fritz Gold Medal of the United Engineering Societies. He was awarded honorary degrees from Columbia University, the University of Pennsylvania, Temple University and the Stevens Institute of Technology.
Death
Fritz died at his home in Bethlehem on February 13, 1913, at age 90
Selected publications
John Fritz, The Autobiography of John Fritz (New York: John Wiley & Sons, 1912). Available online through Beyond Steel: An Archive of Lehigh Valley Industry and Culture.
About John Fritz
Lance Metz, John Fritz: His Role in the Development of the American Iron and Steel Industry and His Legacy to the Bethlehem Community (Easton, PA: Center for Canal History and Technology, 1987).
References
External links
"Finding Aid to The Autobiography of John Fritz, Holographic Manuscript" , Special Collections, Linderman Library, Lehigh University
1822 births
1913 deaths
19th-century American businesspeople
American blacksmiths
American people of Scotch-Irish descent
American steel industry businesspeople
American metallurgists
American people of German descent
Bessemer Gold Medal
Bethlehem Steel people
Engineers from Pennsylvania
John Fritz Medal recipients
People from Chester County, Pennsylvania | John Fritz | Chemistry | 514 |
1,197,294 | https://en.wikipedia.org/wiki/Netgear | Netgear, Inc. (stylized as NETGEAR in all caps), is an American computer networking company based in San Jose, California, with offices in about 22 other countries. It produces networking hardware for consumers, businesses, and service providers. The company operates in three business segments: retail, commercial, and as a service provider.
Netgear's products cover a variety of widely used technologies such as wireless (Wi-Fi, LTE and 5G), Ethernet and powerline, with a focus on reliability and ease-of-use. The products include wired and wireless devices for broadband access and network connectivity, and are available in multiple configurations to address the needs of the end-users in each geographic region and sector in which the company's products are sold.
As of 2020, Netgear products are sold in approximately 24,000 retail locations around the globe, and through approximately 19,000 value-added resellers, as well as multiple major cable, mobile and wireline service providers around the world.
History
Netgear was founded by Patrick Lo in 1996.
On January 31, 2024, NETGEAR announced Patrick Lo's retirement from CEO and the Board of Directors, and CJ Prober became CEO.
The company was listed on the NASDAQ stock exchange in 2003.
Product range
Netgear's focus is primarily on the networking market, with products for home and business use, as well as pro-gaming, including wired and wireless technology.
Netgear also has a wide range of Wifi Range Extenders
ProSAFE switches
Netgear markets network products for the business sector, most notably the ProSAFE switch range. , Netgear provides limited lifetime warranties for ProSAFE products for as long as the original buyer owns the product. Currently focusing on multimedia segment and business product.
Network appliances
Netgear also markets network appliances for the business sector, including managed switches and wired and wireless VPN firewalls. In 2016, Netgear released its Orbi mesh Wi-Fi system, with models for business as well as household use. The system uses a tri-band architecture, similar to the traditional dual-band, but with a dedicated 5 GHz connection between the router and a provided satellite. The addition of a second 5 GHz channel allows the network to distribute its traffic, easing congestion caused by the increasing number of 5 GHz compatible wireless devices present in many household networks. In September 2017, Netgear exited the VPN firewall product category. At CES 2021, the company unveiled the world's first WiFi 6E router that takes advantage of the 6 GHz frequency band in addition to the 5 GHz and 2.4 GHz bands. The 6 GHz frequency increases network capacity where there is high utilization of the 5 GHz and 2.4 GHz bands.
Network-attached storage
Netgear sells NAS devices to small businesses and consumers under the product name ReadyNAS. With this storage hardware line, Netgear vies with competitors like Buffalo, Zyxel and HP. Netgear entered the storage market in May 2007 when it acquired Infrant (originator of the ReadyNAS line). In March 2009, Netgear began to offer an integrated online backup solution called the ReadyNAS Vault. In June 2022 all ReadyNAS product pages was removed and replaced with a link to warranty and support information. Netgear has not yet (August 2022) confirmed that they have withdrawn from the network connected storage market and discontinued the ReadyNAS product line.
Network surveillance cameras
Netgear created home surveillance camera brand Arlo, which was spun out into a separate company in August 2018. Arlo is now publicly traded on the New York Stock Exchange.
Netgear chipsets
Netgear uses Realtek chipsets which can run in monitor mode and perform wireless injection. For this function, a special driver is needed.
Manufacturing
NETGEAR’s primary manufacturers are Cloud Network Technology (more commonly known as Hon Hai Precision or Foxconn Corporation), Delta Electronics Incorporated, Senao Networks, Inc., and Pegatron Corporation, all of which are headquartered in Taiwan. They distribute their manufacturing among a limited number of key suppliers and seek to avoid excessive concentration with any one single supplier.
Manufacturing occurs primarily in Vietnam, Thailand, Indonesia, and Taiwan.
To maintain quality standards, Netgear has established its own product quality organization, based in Singapore and Taiwan, that is responsible for auditing and inspecting process and product quality on the premises of ODMs and JDMs (Joint Development Manufacturers).
Netgear was unaffected by US President Donald Trump's 25% tariffs on Chinese imports. Because all manufacturing is outsourced, the company was able to shift its production lines from China to Vietnam, Thailand and Indonesia.
Product security concerns
In 2014, various Netgear products that were manufactured by SerComm were found to contain a backdoor that allowed unauthorized remote access to the affected devices. Netgear, along with other companies with products manufactured by SerComm that were affected by the aforementioned backdoor, issued firmware updates for some affected products. However, it was shortly found that the updates merely hid the backdoor but did not remove it.
A backdoor also existed on the DG834 series. Any person who can access the router using a web browser, can enable "debug" mode using and then connect via Telnet directly to the router's embedded Linux system as 'root', which gives unfettered access to the router's operating system via its Busybox functionality.
In January 2017, various Netgear products were found to be vulnerable to an exploit that allows third-party access to the router and the internal network and to turn the router into a botnet.
This vulnerability occurs when an attacker can access the internal network or when remote management is enabled on the router. Remote management is turned off by default; users can turn on remote management through advanced settings. Firmware fixes are currently available for the affected devices.
In 2020, a vulnerability was discovered that affected many Netgear home WiFi routers. The problem was in a web server built into the router's firmware. When launching the administration interface, the owner had to enter their password, which was not protected by security. The exploit was posted on GitHub. Netgear issued a security advisory and firmware update to address the issue.
See also
Netgear DG834 (series)
Netgear Switch Discovery Protocol
Netgear SC101
Netgear WGR614L
Netgear WNR3500L
References
External links
American companies established in 1996
Computer companies established in 1996
1996 establishments in California
Companies listed on the Nasdaq
Computer hardware companies
Computer storage companies
Manufacturing companies based in San Jose, California
Technology companies based in the San Francisco Bay Area
Networking companies of the United States
Networking hardware companies
Nortel
Routers (computing)
2003 initial public offerings
Computer companies of the United States | Netgear | Technology | 1,432 |
24,758,132 | https://en.wikipedia.org/wiki/Constant%20%28mathematics%29 | In mathematics, the word constant conveys multiple meanings. As an adjective, it refers to non-variance (i.e. unchanging with respect to some other value); as a noun, it has two different meanings:
A fixed and well-defined number or other non-changing mathematical object, or the symbol denoting it. The terms mathematical constant or physical constant are sometimes used to distinguish this meaning.
A function whose value remains unchanged (i.e., a constant function). Such a constant is commonly represented by a variable which does not depend on the main variable(s) in question.
For example, a general quadratic function is commonly written as:
where , and are constants (coefficients or parameters), and a variable—a placeholder for the argument of the function being studied. A more explicit way to denote this function is
which makes the function-argument status of (and by extension the constancy of , and ) clear. In this example , and are coefficients of the polynomial. Since occurs in a term that does not involve , it is called the constant term of the polynomial and can be thought of as the coefficient of . More generally, any polynomial term or expression of degree zero (no variable) is a constant.
Constant function
A constant may be used to define a constant function that ignores its arguments and always gives the same value. A constant function of a single variable, such as , has a graph of a horizontal line parallel to the x-axis. Such a function always takes the same value (in this case 5), because the variable does not appear in the expression defining the function.
Context-dependence
The context-dependent nature of the concept of "constant" can be seen in this example from elementary calculus:
"Constant" means not depending on some variable; not changing as that variable changes. In the first case above, it means not depending on h; in the second, it means not depending on x. A constant in a narrower context could be regarded as a variable in a broader context.
Notable mathematical constants
Some values occur frequently in mathematics and are conventionally denoted by a specific symbol. These standard symbols and their values are called mathematical constants. Examples include:
0 (zero).
1 (one), the natural number after zero.
(pi), the constant representing the ratio of a circle's circumference to its diameter, approximately equal to 3.141592653589793238462643.
, approximately equal to 2.718281828459045235360287.
, the imaginary unit such that .
(square root of 2), the length of the diagonal of a square with unit sides, approximately equal to 1.414213562373095048801688.
(golden ratio), approximately equal to 1.618033988749894848204586, or algebraically, .
Constants in calculus
In calculus, constants are treated in several different ways depending on the operation. For example, the derivative (rate of change) of a constant function is zero. This is because constants, by definition, do not change. Their derivative is hence zero.
Conversely, when integrating a constant function, the constant is multiplied by the variable of integration.
During the evaluation of a limit, a constant remains the same as it was before and after evaluation.
Integration of a function of one variable often involves a constant of integration. This arises due to the fact that the integral is the inverse (opposite) of the derivative meaning that the aim of integration is to recover the original function before differentiation. The derivative of a constant function is zero, as noted above, and the differential operator is a linear operator, so functions that only differ by a constant term have the same derivative. To acknowledge this, a constant of integration is added to an indefinite integral; this ensures that all possible solutions are included. The constant of integration is generally written as 'c', and represents a constant with a fixed but undefined value.
Examples
If is the constant function such that for every then
See also
Constant (disambiguation)
Expression
Level set
List of mathematical constants
Physical constant
References
External links
Algebra
Elementary mathematics | Constant (mathematics) | Mathematics | 867 |
1,105,530 | https://en.wikipedia.org/wiki/Digital%20Angel | Digital Angel Corporation is a developer and publisher of consumer applications and mobile games designed for tablets, smartphones and other mobile devices, as well as a distributor of two-way communications equipment in the U.K.
Products and services
The company formerly developed Global Positioning System (GPS) and radio-frequency identification (RFID) technology products for consumer, commercial, and government sectors. The company manufactured tracking devices for people, animals, the food supply, government/military arena, and commercial assets. Included in this product line were RFID applications, end-to-end food safety systems, GPS/Satellite communications, and telecommunication, security infrastructure, and the controversial Verichip human implant, a product which has caused concern among advocates of civil liberties.
Applications for this technology include pets, wildlife and livestock identification using implantable RFID microchips, scanners and antennas.
Digital Angel has also researched and developed GPS Search and Rescue Transponders that integrated geosynchronous communications for use by the military and the private sector to track aircraft, ships, and other high-value assets.
History
Digital Angel formerly owned a minority position (49%) in VeriChip, but divested itself of the stake in 2008. VeriChip Corporation and Steel Vault Corporate later merged to form PositiveID, and in 2010 PositiveID attempted a friendly acquisition of Digital Angel, but the bid was unanimously rejected by its board of directors.
The animal identification products subsidiary Destron Fearing was sold to Allflex USA, in July, 2011, for $25 million.
Subsidiaries
Digital Angel owns and operates Signature Communications, a distributor of two-way communications equipment in the U.K. Products offered range from conventional radio systems used by the majority of its customers, for example, for safety and security uses and construction and manufacturing site monitoring, to trunked radio systems for large-scale users, such as local authorities and public utilities.
Chief executive officers
L. Michael Haller – appointed CEO on August 23, 2012.
Daniel E. Penni – appointed "Interim CEO" on 1 February 2012.
Joseph J. Grillo – former CEO of Digital Angel, beginning on January 2, 2008. Succeeding Kevin McGrath. Grillo is the former President and Chief Executive Officer of the Global Technologies Division of Assa Abloy. Randy Geissler was CEO from 2000 to 2003.
See also
Masonic Child Identification Programs
PositiveID
References
External links
www.digitalangelcorp.com
Electronics companies of the United States
Companies based in Florida
Companies based in Palm Beach County, Florida
Companies established in 1993
Radio-frequency identification
Companies formerly listed on the Nasdaq | Digital Angel | Engineering | 527 |
6,674,625 | https://en.wikipedia.org/wiki/DISPERSION21 | DISPERSION21 (also called DISPERSION 2.1) is a local scale atmospheric pollution dispersion model developed by the air quality research unit at Swedish Meteorological and Hydrological Institute (SMHI), located in Norrköping.
The model is widely used in Sweden by local and regional environmental agencies, various industrial users, consultant services offered by SMHI and for educational purposes.
Features and Capabilities
Some of the basic features and capabilities of DISPLAY21 are:
Source types: Multiple point, area, and volume sources as well as street canyons.
Source releases: Surface, near surface and elevated sources.
Source locations: Urban or rural locations.
Plume types: Continuous or intermittent buoyant plumes
Plume dispersion treatment: Gaussian model treatment using Green's functions and includes multiple reflections.
Terrain types: Simple terrain with no more than 10 degree slopes.
Building effects: Building downwash algorithms are included.
Meteorological data: The model includes a preprocessor to produce the meteorological parameters needed to characterize the atmospheric turbulence as well as to produce wind speed and direction profiles.
The street canyon module includes some atmospheric chemistry for photochemical reactions.
See also
Bibliography of atmospheric dispersion modeling
Atmospheric dispersion modeling
List of atmospheric dispersion models
Swedish Meteorological and Hydrological Institute
Further reading
For those who are unfamiliar with air pollution dispersion modelling and would like to learn more about the subject, it is suggested that either one of the following books be read:
www.crcpress.com
www.air-dispersion.com
References
External links
SMHI web site click on 'Products & Services', then on 'Environment', and then on 'Dispersion'
Atmospheric dispersion modeling | DISPERSION21 | Chemistry,Engineering,Environmental_science | 348 |
74,420,274 | https://en.wikipedia.org/wiki/Clara%20Saraceno | Clara Jody Saraceno (born 1983) is a laser scientist whose research involves the development of ultrafast lasers, a technology whose applications include ultrafast laser spectroscopy, and imaging biological processes at the molecular scale. Born in Argentina and educated in France and Switzerland, she works in Germany as a professor in the Faculty for Electrical Engineering of Ruhr University Bochum, where she holds the Chair of Photonics and Ultrafast Laser Science.
Education and career
Saraceno was born in 1983 in Buenos Aires, Argentine. She studied optics and photonics at the Institut d'optique Graduate School in France, part of Paris-Saclay University, after which she worked in the US for Coherent, Inc. from 2007 to 2008. Returning to graduate study at ETH Zurich in Switzerland, she completed a PhD in 2012, under the supervision of physicist Ursula Keller.
After postdoctoral research at ETH Zurich and the University of Neuchâtel in Switzerland, she joined Ruhr University Bochum in Germany as an associate professor in 2016.
Recognition
Saraceno's doctoral thesis won the 2013 Quantum Electronics and Optics Division Thesis Prize of the European Physical Society. She was a 2016 recipient of the Sofia Kovalevskaya Award of the Alexander von Humboldt Foundation.
She became an Optica Ambassador in 2019, and was named as a 2022 Optica Fellow, "for seminal contributions to ultrafast science and technology, as well as outstanding service to the optics community".
References
External links
Photonics and Ultrafast Laser Science at Ruhr University Bochum
Living people
Engineers from Buenos Aires
Argentine emigrants to Germany
Electrical engineers
Women electrical engineers
Laser researchers
Paris-Saclay University alumni
ETH Zurich alumni
Academic staff of Ruhr University Bochum
Fellows of Optica (society)
1983 births | Clara Saraceno | Engineering | 358 |
31,970,422 | https://en.wikipedia.org/wiki/List%20of%20taxonomic%20authorities%20by%20name | Following is a partial list of taxonomic authorities by name — for taxonomists with some common surnames.
Adams
Andrew Leith Adams (1827–1882), Scottish zoologist
Arthur Adams (1820–1878), English physician and naturalist, brother of Henry Adams
Charles Baker Adams (1814–1853), American conchologist
Charles Dennis Adams (C.D.Adams, 1920–), botanist
Henry Adams (1813–1877), English naturalist and conchologist, brother of Arthur Adams
Johannes Michael Friedrich Adams (Adams, 1780–1838), Russian botanist
Joseph Edison Adams (J.E.Adams, 1904–1981), botanist
Laurence George Adams (L.G.Adams, 1929–), botanist
Robert Phillip Adams (R.P.Adams, 1939–), botanist
Chandler
Donald S. Chandler, an entomologist
Gregory T. Chandler, a botanist
Harry Phylander Chandler (1917–1955), an American entomologist
Marjorie E.J. Chandler, an English paleobotanist
Peter Chandler, an entomologist
Clark
See for species named after taxonomic authorities named Clark.
Austin Hobart Clark (1880–1954), American zoologist
Benjamin Preston Clark, English entomologist
Eugenie Clark (1922–2015) (E. Clark), ichthyologist
Hubert Lyman Clark (1870–1947) (H.L. Clark), zoologist specialist of echinoderms
James Michael Clark (J.M. Clark)
John Clark (1885–1956), Australian entomologist
John L. Clark (J.L.Clark), botanist
Gray
See for species named after taxonomic authorities named Graii.
Asa Gray (1810–1888), American botanist (IPNI=A.Gray)
George Robert Gray (1808–1872), British zoologist; son of Samuel Frederick Gray
John Edward Gray (1800–1875), British zoologist; son of Samuel Frederick Gray (IPNI=J.E.Gray)
Michael R. Gray, Australian arachnologist
Samuel Frederick Gray (1766–1828), British botanist (IPNI =Gray)
Note: if the name refers to a botanist, it is most likely Samuel Frederick Gray; & if it refers to a zoologist it is most likely John Edward Gray
Schneider
Gotthard Schneider (Gotth.Schneider), German lichenologist and teacher
Johann Gottlob Schneider (1750–1822), German classicist and naturalist
Camillo Karl Schneider (C.K.Schneider, 1876–1951), Austrian botanist
Scott Alexander Schneider (born 1982), American coccidologist
Smith
See for species named after taxonomic authorities named Smith.
See List of taxonomic authorities named Smith
Thomson
Carl Gustaf Thomson (1824–1899), Swedish entomologist - Thomson is his official abbreviation
James Thomson (1828–1897), American entomologist
Scott Thomson (born 1966), Australian taxonomist and palaeontologist (turtles). Generally abbreviated as S. Thomson
Thomas Thomson (1817–1878), British physician and botanist - Thomson is his official botanical author abbreviation according to IPNI
Walker
See for species named after taxonomic authorities named Walker.
Alick Donald Walker (A. Walker, 1925–1999), British palaeontologist
Bryant Walker (1856–1936), American amateur malacologist
Cyril Alexander Walker (1939–2009), British palaeontologist
Edmund Murton Walker (E.M. Walker, 1877–1969), Canadian entomologist
Francis Walker (F. Walker, 1809–1874), entomologist
Warren F. Walker (W.F. Walker)
See also
— alphabetical.
— alphabetical.
— all taxa fields, alphabetical.
:Category: Taxonomists
.taxonomic authorities by name
taxonomic authorities | List of taxonomic authorities by name | Biology | 757 |
30,332,230 | https://en.wikipedia.org/wiki/Optofluidics | Optofluidics is a research and technology area that combines the advantages of fluidics (in particular microfluidics) and optics. Applications of the technology include displays, biosensors, lab-on-chip devices, lenses, and molecular imaging tools and energy.
History
The idea of fluid-optical devices can be traced back at least as far as the 18th century, when spinning pools of mercury were proposed (and eventually developed) as liquid-mirror telescopes. In the 20th century new technologies such as dye lasers and liquid-core waveguides were developed that took advantage of the tunability and physical adaptability that liquids provided to these newly emerging photonic systems. The field of optofluidics formally began to emerge in the mid-2000s as the fields of microfluidics and nanophotonics were maturing and researchers began to look for synergies between these two areas. One of the primary applications of the field is for lab-on-a-chip and biophotonic products.
Companies and technology transfer
Optofluidic and related research has led to the formation of a number of new products and start-up companies. Varioptic specializes in the development of electrowetting based lenses for numerous applications. Optofluidics, Inc. was launched in 2011 from Cornell University in order to develop tools for molecular trapping and disease diagnosis based on photonic resonator technology. Liquilume from UC Santa Cruz specializes in molecular diagnostics based on arrow waveguides.
In 2012, the European Commission has launched a new COST framework that is concerned solely with optofluidic technology and their application.
Examples of specific applications
Given the broad range of technologies that have already been developed in the field of microfluidics and the many potential applications of integrating optical components into these systems, the range of applications for optofluidic technology is vast.
Laminar flow-based optofluidic waveguides
Optofluidic waveguides are based on principles of traditional optical waveguides and microfluidic techniques used to maintain gradients or boundaries between flowing fluids. Yang et al. used microfluidic techniques based on laminar flow to generate fluid-based gradient-indices of refraction. This was implemented by flowing two cladding layers of deionized water () around a core layer of ethylene glycol (). Using traditional microfluidic techniques to generate and maintain gradients of fluids, Yang et al. were able maintain refractive index profiles ranging from step-index profiles to depth-varying gradient-index profiles. This allowed for the novel and dynamic generation of complex waveguides.
Optofluidic photonic crystal fibers
Optofluidic Photonic-crystal fibers (PCFs) are traditional PFCs modified with microfluidic techniques. Photonic-crystal fibers are a type of fiber optic waveguide with cladding layers arranged in a crystalline fashion in their cross-sectional areas. Traditionally, these structured cladding layers are filled with a solid-state material with a different refractive indices or are hollow. Each cladded core then acts as a single mode fiber passing multiple light paths in parallel. Traditional PCFs are also limited to using hollow or solid-state cores that must be filled at the time of construction. This means that the material properties the PCFs were set at the time of construction and were limited to the material properties of solid-state materials.
Viewig et al. used microfluidic technology to selectively fill sections of photonic crystal fibers with fluids that exhibit a high degree of Kerr nonlinearity such as toluene and carbon tetrachloride. Selectively filling hollow PFCs with fluid allows for control over thermal diffusion via spatial segregation and allows for the ability to pattern multiple different types of fluid. Using non-linear fluids, Vieweg et al. were able to generate a soliton continuum which has many applications for imaging and communications.
Bubble laser
A bubble laser can be created by add laser dye and smectic liquid crystal to soapy water and producing foam. The resulting optical cavity varies in resonant frequency depending on size, air pressure, and electric fields.
See also
List of optofluidics researchers
References
Further reading | Optofluidics | Materials_science | 876 |
67,665,516 | https://en.wikipedia.org/wiki/Window%20well | A window well is a recess in the ground around a building to allow for installment of bigger windows in a basement either below ground or partially below ground. By making it possible to put in a larger window, the window can act as a safer emergency exit in case of fire as well as letting in additional daylight for the enjoyment of the people inside. Such a (basement) window where people can escape through in case of an emergency is sometimes called an egress window.
Minimum window sizes may be required by building code (particularly for bed and living rooms) due to fire safety, which often makes it necessary to install window wells. Window wells are sometimes covered by a window well cover to avoid snow and debris to enter the pit, as well as preventing fall injuries into the window well.
Care should be taken to install window wells correctly to ensure proper drainage and avoid leaks.
See also
Alcove (architecture)
Niche (architecture)
References
Well
Architectural elements | Window well | Technology,Engineering | 192 |
44,250,724 | https://en.wikipedia.org/wiki/Foucault%27s%20lectures%20at%20the%20Coll%C3%A8ge%20de%20France | On the proposal of Jules Vuillemin, a chair in the department of Philosophy and History was created at the to replace the late Jean Hyppolite. The title of the new chair was The history of systems of thought and it was created on November 30, 1969. Vuillemin put forward Michel Foucault to the general assembly of professors and Foucault was duly elected on 12 April 1970. He was 44 years old, and at the time was relatively unknown beyond the borders of his native France. As required by this appointment, he held a series of public lectures from 1970 until his death in 1984 (excepting a sabbatical year in 1976–1977). These lectures, in which he further advanced his work, were summarised from audio recordings and edited by Michel Senellart. They were subsequently translated into English and further edited by Graham Burchell and published posthumously by St Martin's Press.
Lectures On The Will To Know (1970–1971)
This was an important time for Foucault and marks an important switch of methodology from 'archaeology' to 'genealogy' (according to Foucault he never abandoned the archaeology method). This was also a period of transition of thought for Foucault; the Dutch TV-televised Foucault Noam Chomsky Human nature Justice versus Power debate of November 1971 at the Eindhoven University of Technology appears at this exact time period as his first inaugural lecture were delivered at the entitled "the Order Of Discourse" delivered on 2 December 1970 (translated and published into English as "The Discourse On Language") then a week later (9 December 1970) his first ever full inaugural lecture course was delivered at the "The Will to Knowledge" course Foucault promised to explore; "fragment by fragment," the "morphology of the will to knowledge," through alternating historical periods, inquiries and theoretical questioning. The lectures produced were called "Lectures On The Will To Know"; all of this within a space of a year.
The first phase of Foucault's thought is characterized by knowledge construction of various types and how each thread of knowledge systems combine together to produce a series of networks (Foucault uses the term 'Grille') to produce a successful fully functional 'subject' and a workable fully functional human society. Foucault uses the terms epistemological indicators and epistemological breaks to show, contrary to popular opinion, that these "indicators" and "breaks" require skilled trained technical group of 'specialists' in the various knowledge fields and a trained rigorous professionalized regulatory body of which know-how on behalf of those who use the terms (discourse formations or "speech/discourse") with a professional body that can make the terms used stand up to further rational scrutiny. Scientific knowledge for Foucault isn't an advancement for human progress as is so often portrayed by the human sciences (such as the humanities and the social sciences) but is much more of a subtle method of organizing and producing firstly an individual subject, and secondly, a fully functional society functioning as a self-replicated control apparatus not as a group of 'free' atomized individuals but as a collective societal, organised (or drilled) unit both in terms of industrial Production, labour power and a militarily organized unit (in the guise of armies) which is beneficial for the production of "epistemological indicators" or "breaks" enabling society to "control itself" rather than have external factors (such as the state for example) to do the job.
In the inaugural lecture course "The Will To Know" Foucault goes into detail on how the 'natural order of things' from the 16th century transpired into a fully organised human society which includes a "Governmentality" apparatus and a complex machine (by "governmentality", Foucault means a state apparatus which is conceived as a scientific machine) as a rational organizing principle. This was the first time (contrary to popular opinion that this was a rather late invention in Foucault's thought) that Foucault started to go into the Greek dimensions of his thought of which he would return to in later lectures towards the end of his life. First of all a few pointers should be made explicit on certain points. Foucault mentions the western notions of money, production and trade (Greek society) starting about 800 BCE to 700 BCE. However, other 'non-western' societies also had these very same problems and is automatically assumed by some historians that these were entirely western inventions. This isn't entirely true; China and India for example had the most sophisticated trading and monetary institutions by the 6th century B.C.E., indeed the concept of a corporation existed in India from at least 800 BCE and lasted until at least 1000 C.E.
Most importantly there was a social security system in India at this time. Foucault begins his notions from these lectures on the very notion of truth and the 'Will to knowledge' and the challenge is on when Foucault asks the very question of the entire western philosophical and political tradition: Namely knowledge (at least scientific knowledge) and its close association with truth is entirely desirable and is politically and philosophically natural and neutral. First of all Foucault puts these notions (at least its political notions) to a thorough test, firstly, Foucault asks the politically 'neutral' question on the very first appearance of money which became not only an important economic symbol but above all else became a measure of value and a unit of account.
Money once established as a social process and social reality had (if one could say the word) an extremely rocky and precarious history. First of all while it had a social reality but the actual social authority to use money didn't develop a standard practice or knowledge on how to use it; it was rather undisciplined. Kings and emperors could squander large taxation revenues with impunity regardless of the consequences. They could default on repayments on loans as witnessed during the Hundred Years' War and During the Anglo-French War (1627-1629). Above all else kings and monarchs could take out forced loans and get others(their subjects) to pay for these forced loans and to add insult to injury get them to pay interest on the loans at extortionate rates of interest charged on the loans because they and their advisers regarded it as their own 'income'. However, whole societies were dependent on money particularly when the whole of society had to use and be ready for its function. Money took at least 3,000 years of history to get a more disciplined approach and became the sole prerogative of the fiscal responsibility of the state after the medieval 'order of things' was entirely dismantled 'to get it right' namely; the ruthlessness and rigorous efficiency needed for its proper function and it wasn't until the 16th century with the advent of modern political economy with its analysis of production, labour and trade you then get a sense of why money, particularly its relationship with capital and its complex relationship with the rest of society conversion, from labour power into money via the essential route of surplus value became a much maligned and misunderstood category and hot potato. Foucault now is asking how is it that modern western political economy, together with political philosophy and political science came to ask the question concerning money but was utterly perplexed by it (this is a question that particularly irritated and irked Karl Marx throughout his life)? That money and its various association with production, labour, government and trade was beyond doubt but its exact relationship with the rest of society was entirely missed by economists but yet still its version of events was entirely accepted as true? Foucault begins to try to go into the whole production of truth (both philosophical and political) its whole "breaks" "discontinuity" 'epistemological unconscious' and theoretical splitting "Episteme". From this Greek period starting from 800 BCE Foucault pursues the path of scientific and political knowledge the emergence and conditions of possibility for philosophical knowledge and ends up with "the problem of political knowledge (i.e. Aristotelian notions of the political animal) of what is necessary in order to govern the city and put it right." He then divided his work on the history of systems of thought into three interrelated parts, the "re-examination of knowledge, the conditions of knowledge, and the knowing subject."
Penal Theories and Institutions (1971–1972)
In these lectures, to be published in English in 2020, Foucault used the first precursor of Discipline and Punish to study the foundations of what he calls "disciplinary institutions" (punitive power) and the productive dimensions of penalty.
The Punitive Society (1972–1973)
In these lectures, published in English in 2015, continued the investigation of power and penal institutions begun in 1971-2. Foucault spent a lot of time during this period trying to make intelligible the internal and external dynamics of what we call the prison. He questioned, "What are the relations of power which made possible the historical emergence of something like the prison?". This was correlated to three terms; firstly 'measure' "a means of establishing or restoring order, the right order, in the combat of men or the elements; but also a matrix of mathematical and physical knowledge."(treated in more detail in The Will To Knowledge lectures of 1971); Secondly the 'inquiry' "a means of establishing or restoring facts, events, actions, properties, rights; but also a matrix of empirical knowledge and natural sciences"(from the 1972 lectures Theories On Punishment and Penal Theories and Institutions) and thirdly 'the examination' treated as "the permanent control of the individual, like a permanent test with no endpoint". Foucault links the examination with 18th century Political economy and the productive labourers with the wealth they produce and the forces of production.
Abnormal (1974–1975)
Influenced by the work of Georges Canguilhem, in these lectures (first published in English in 2003) Foucault explored how power defined the categories of "normality" and "abnormality" in modern psychiatry.
"Society Must Be Defended" (1975–1976)
This series of lectures forms a trilogy with Security, Territory, Population and The Birth of Biopolitics, and it contains Foucault's first discussion of biopower. It also contains an explanation of the term "civil war" in the form of rigorous treatment of a working definition. Foucault goes into great detail how power (as Foucault saw it) becomes a battleground drifting from civil war to generalized pacification of the individual and particularly the systems he (the individual) relies upon and to which he gives loyalty: "According to this hypothesis, the role of political power is perpetually to use a sort of silent war to re-inscribe that relationship of force, and to re-inscribe it in institutions, economic inequalities, language, and even the bodies of individuals." Foucault begins to explain that this generalized form of power is not only rooted in disciplinary institutions but is also concentrated in "political sovereignty, the military, and war," so it is in turn spread evenly throughout modern society as a network of domination.
Foucault then discusses what lies behind the "academic chestnut" which could not be deciphered by his historical predecessors: namely the disjointed and discontinuous movement of history and power (bio-power). What is meant by this? For Foucault's predecessors, history was concerned by deeds of monarchs and a full list of their accomplishments in which the sovereign is presented in the text as doing all things 'great,' added to this 'greatness' of deeds this 'greatness' of the sovereign was accomplished all by the sovereign himself without any help; monument building, allegedly built by the monarch, without any help from skilled and trained professionals serves as a perfectly good example of the sovereign "greatness". However, for Foucault, this is not the case. Foucault's genealogy comes into play here where Foucault tries to build a bridge between two theoretical notions: disciplinary power (disciplinary institutions) and biopower. He investigates the constant shift throughout history between these two 'paradigms,' and what developments-from these two 'paradigms' became new subjects. The previous historical dimensions so often portrayed by historians Foucault argues, was sovereign history, which acts as a ceremonial tool for sovereign power "It glorifies and adds lustre to power. History performs this function in two modes: (1) in a "genealogical" mode (understood in the simple sense of that term) that traces the lineage of the sovereign. By the time of the 17th century with the development of mercantilism, statistics (mathematical statistics) and political economy this reaches a most vitriolic and vicious form later to be called nation states where whole populations were involved (in the guise of armies both industrial and military), in which a continuous war is enacted out not amongst ourselves (the population) but in a struggle for the state's very existence which ultimately leads to a "thanatopolitics" (a philosophical term that discusses the politics of organizing who should live and who should die (and how) in a given form of society) of the population on a large industrial scale.
This is where Foucault discusses a "counterhistory" of "race struggle or race war." According to Foucault, Marx and Engels used or borrowed the term "race" and transversed the term race into a new term called "class struggle" which later Marxist accepted and began to use. This is more partly to do with Marx's antagonistic relationship with Carl Vogt who for his time was a convinced polygenist which Marx and Engels had inherited Vogt's belief. Foucault quotes letters written by Marx to Engels in 1854 and Joseph Weydemeyer in 1852
Foucault challenges the traditional notions of racism in explaining the operation of the modern state. When Foucault talks of racism he is not talking about what we might traditionally understand it to be–an ideology, a mutual hatred. In Foucault's reckoning modern racism is tied to power, making it something far more profound than traditionally assumed.
Tracing the genealogy of racism, Foucault proposes that 'race', previously used to describe the division between two opposing societal groups distinguished from one another for example by religion or language, came to be conceived in the late 18th century in biological terms. The concept of "race war" that referred to conflict over the legitimacy of the power of the established sovereign, was "reformulated" into a struggle for existence driven by concern about the biopolitical purity of the population as a single race that could be threatened from within its own body. For Foucault "racism is born at the point when the theme of racial purity replaces that of race struggle" (p. 81).
For Foucault, racism "is an expression of a schism within society ... provoked by the idea of an ongoing and always incomplete cleaning of the social body…it structures social fields of action, guides political practice, and is realized through state apparatuses…it is concerned with biological purity and conformity with the norm" (pp.43–44). In modern states, racism is not defined by the action of individuals, rather it is vested in the State and finds form in its structures and operation – it is state racism.
State racism serves two functions. Firstly, it makes it possible to divide the population into biological groups, "good and bad" or "superior or inferior" 'races'. Fragmented into subspecies, the population can be brought under State control. Secondly, it facilitates a dynamic relationship between the life of one person and the death of another. Foucault is clear that this relationship is not one of warlike confrontation but rather a biological one, that is not based on the individual but rather on life in general "the more inferior species die out, the more abnormal individuals are eliminated the fewer degenerates there will be in the species as a whole, and the more I – as species rather than individual – can live, the stronger I will be, the more vigorous I will be, I will be able to proliferate" (p.255)
In effect race, defined in biological terms, "furnished the ideological foundation for identifying, excluding, combating, and even murdering others, all in the name of improving life not of an individual but of life in general" (p. 42). What is important here is that racism, inscribed as one of the modern state's basic techniques of power, allows enemies to be treated as threats, not political adversaries. But through what mechanism are these threats treated? Here the technologies of power described by Foucault become important.
Foucault argues that new technologies of power emerged in the second half of the 18th century, which Foucault termed biopolitics and biopower(Foucault uses both terms synonymously), these technologies focused on man-as-species and were concerned with optimising the state of life, with taking control of life and intervening to "make live and let die". Importantly, Foucault argues, the technologies did not replace the technologies of sovereign power with their exclusive focus on disciplining the individual body to be more productive by punishing or killing individuals, but embedded themselves into them. It was in exploring how this new power, with life as its object, could come to include the power to kill that Foucault theorizes the emergence of state racism.
Foucault argues that the modern state must at some point become involved with racism in order to function since once a State functions in a biopolitical mode it is racism alone that can justify killing. Determined as a threat to the population, the State can take action to kill in the name of keeping the population safe and thriving, healthy and pure. It is racism that allows the right to kill to be squared off with a power that seeks to improve life. State racism delivers actions that while appearing to derive from altruistic intentions, veil the murder of the "Other" Following this argument to its logical end, it is only when there is never a need for the State to claim the right to kill or to let die that State racism will disappear.
Since killing is predicated on racism, it follows that the "most murderous states are also the most racist" (p.258). Foucault refers to the way in which Nazism and the state socialism of the Soviet Union dealt with ethnic or social groups and their political adversaries as examples of this.
Threats, however, can change over time and here the utility of 'race' a concept comes into its own. While never defining 'race', Foucault suggests that the word 'race' is "not pinned to a stable biological meaning" (p. 77). with the implication that it is a concept that is socially and historically constructed where a discourse of truth is enabled. This makes 'race' something that is easy for the State to adopt and exploit for its own purpose. 'Race' becomes a technology that is used by the state to structure threats and to make decisions over the life and death of sub-populations. In this way it helps to explain how the idea of 'race' or cultural difference are used to wage wars such as the "war on terror" or the "humanitarian war" in East Timor.
Security, Territory, Population (1977–1978)
Source:
The course deals with the genesis of a political knowledge that was to place at the centre of its concerns the notion of population and the mechanisms capable of ensuring its regulation but even of its procedures and means employed to ensure, in a given society, "the government of men". A transition from a "territorial state" to a "population state" (Nation state)?
Foucault examines the notion of biopolitics and biopower as a new technology of power over populations that is distinct from punitive disciplinary systems, by tracing the history of governmentality, from the first centuries of the Christian era to the emergence of the modern nation state. These lectures illustrate a radical turning point in Foucault's work at which a shift to the problematic of the government of self and others occurred.
Foucault's challenge to himself in these series of lectures is to try and decipher the genealogical split between power in ancient and Medieval society and late modern society, such as our own. By split Foucault means power as a force for manipulation of the human body. Previous notions of power failed to account for the historical subject and general shifts in techniques of power-according to Foucault's genealogy or genesis of power – it was totally denied that manipulation of the human body by unforeseen, outside forces ever existed. According to this theory, it was human ingenuity and man's ability to increase his own rationalisation was the primary motion behind social phenomena and the human subject and change was a result of increasing human reason and human conscience ingenuity. Foucault denies that any such notion had ever existed in the historical record and insists that this kind of thought is a misleading abstraction. Foucault cites the main driving force behind this set of accelerated change was the modern human sciences and the technologies both available to skilled professionals from the 16th century and a whole set of clever techniques used to shift the whole old social order into the new order of things. However, what was significant was the notion of Population practised upon the entire human species on a global mass scale, not in separately locally defined areas. By population, Foucault means its fluidness and malleability, Foucault refers to 'a multiplicity of men, not to the extent that they are nothing more than individual bodies, but to the extent that they form, on the contrary, a global mass that is affected by overall processes of birth, death, production, taxation, illness and so forth, one should also take note that Foucault does not just mean population as singular event but a means of circulation tied to factors of security. What again was also significant was the idea of "freedom" the population's "freedom" which was the new modern Nation state and the 'neo-discourse' erected around such notions as freedom, work and Liberalism, the ideological stance of the state (mass popular democracy and the voting franchise) and the state was only too willing to recognize and give freedom for example as the object of security. Population, in Foucault's understanding, is understood as a self-regulating mass;an agglomeration or circulation of people and things which co-operate and co-produce order free from heavy state regulation the state governs less allowing the population to "govern itself". For Foucault, the freedom of population is grasped at the level of how elements of population circulate. Techniques of security enact themselves through, and upon, the circulation which occurs at the level of population. In Foucault's opinion the modern concept of population, as opposed to the ancient Antiquity and medieval version of "populousness" which has in its roots going as far back as the time period of the Book of Numbers in the Old Testament Bible and the work that it sustained both in political theory and practice certainly does so; or, at least, the construction of the concept population is central to the creation of new orders of knowledge, new objects of intervention, new forms of subjectivity.
However, in order to fully understand what Foucault is trying to convey a few things should be said about the alteration techniques used that Foucault talks about in this series of lectures. The ancient and medieval version of Political power was centered around a central figure who was called a King, Emperor, Prince or ruler (and in some cases the pope) of his principle territory whose rule was considered absolute (Absolute monarchy) by both Political philosophy and political theory of the day even in our time such notions still exist. Foucault uses the term population state to designate a new founded technology founded on the principal of security and territory which would mean a "population" to govern on a global mass with each population having its own territorial integrity(a separate nation) mapped out by experts in treaty negotiations and the new emerging field of 15th century Advances in map-making technologies and the profession of Cartography eventually producing in the 18th century what we now know as nation states. These technologies take place at the level of "population" Foucault argues, and with the shifting aside of the body of the King or territorial ruler. By the time of the ending of the medieval period the body(or the persona of the king)of the territorial ruler became under increasingly under financial pressure and a cursory look at the medieval financial records tends to show that the monarch could not pay back all debts due to his creditors; the monarch would easily and readily default on loans due to any creditors causing financial ruin to creditors. Foucault notices that by the time of the 18th century several changes began to take place like the re-organization of armies, an emerging industrial working population begins to appear, (both military and industrial), the emergence of the Mathematical sciences, Biological sciences and Physical sciences which, coincidently gave birth to a-what Foucault calls-Biopower and a political apparatus (machine) to take care of biological (in the form of medicine and health) and political life (mass democracy and the voting franchise for the population). An apparatus (both economic and political) was required much more sophisticated than previous social organisations of previous societies had at their disposal. For example, Banks, which function as financial intermediaries and tied to the apparatus of the new 'state' machine which can easily pay back any large scale debts (large debts) which the King cannot, due to the king's own financial resources are limited;the king cannot pay back for example, the national debt, nor pay for a modern army out of his own personal resources, which can amount to trillions of US Dollars out of his own personal finances, that would be both impracticable and impossible.
The Birth of Biopolitics (1978–1979)
The Birth of Biopolitics develops further the notion of biopolitics that Foucault introduced in his lectures on "Society must be defended". It traces how eighteenth-century political economy marked the birth of a new governmental rationality and raises questions of political philosophy and social policy about the role and status of neo-liberalism in twentieth century politics.
Over the course of many centuries the association between biological phenomena and human political behaviour has received a great deal of attention. Recently (the last 60 years or so) in the academic field and journals there has been some development within the field of political and biological behaviour. In his College de France lecture course of January 1978 Foucault use the term Biopolitics (not for the first time) to denote politic power over every aspect of human life. Why did Foucault use the term 'biopolitics' in the first place? First of all the term has many different meanings to many different people and to fully understand the term as Foucault saw and used and understood it, we have to look at the very different meanings of the concept. For Foucault the term means to him the association between biological phenomena and human political behaviour maximizing and increasing the human abilities machine (as we know the term). Over the course of evolutionary time this abilities machine of man becomes species specific, such as language capabilities, neuronal and cognitive capabilities so on and so forth. This then becomes over the course of the history of discursive technologies of scientific knowledge, Foucault argues, a field of knowledge established by groups of experts in disciplines, such as astronomy, biology, chemistry, geoscience, physics, anthropology, archaeology, linguistics, psychology, sociology, and history, for example.
The study of a new and rigorous discipline allied together with a new language (discourse technologies) in which a grasp of the new language is needed developing into a powerful force in the political realm as well as biological evolution the two become powerful allies (both biology and politics). Genetics and the change that develops (over time) over the course of the human organism existence. However, the two become co-joined unwittingly but one of them both political philosophy and political science have specific problems, both cannot have or lay claim to independent knowledge which is problematic for both lines of thought. Not in the case of ideology (as in Marxism) but in the case of discursive technologies. Foucault insists that the scientific knowledge being presented by historians is not an endeavour by the whole of humankind, particularly when written about by historians who claim that 'man' invented the sciences anymore than the Nazi represented the whole of humankind and the whole of humankind were to blame for the Nazi atrocities the ultimate embodiment of evil. But is, for all attempts and purposes a collaborative enterprise by groups of specially trained specialists producing a scientific community who have unfettered access to the whole of society through their scientific knowledge and expertise.
Change does indeed happen both within the organism and the organisms properties, the specific species is unable to correct them directly and biological change moves beyond any individual or single member of the species. However, these changes are aimed at the species as a whole and characteristics and traits are retained both at the biological, ecological and environmental level. In the human sciences (biology and genetics) these changes happen at a genetic and biological level which are unalterable and transpire from one generation to the next not at the individual level of the species. This is at the heart of the core theory of Charles Darwin and his proponents and the theory of Evolution and natural selection. Foucault's analysis try's to show that contrary to previous thought that the modern human sciences were somehow an obscure universal objective source which somehow had an absence of any lineage, took over the role of the Christian church in disciplining the body by replacing the soul and confession of the Catholic church plus also the specific director of the process which in this case would be the deity (God), with indefinite supervision and discipline. However, these new techniques required a new 'director(s)' or 'editor(s)' who replaced the priestly and Pharaonic versions of much similar past vintages. These new governmental mechanism based upon the right of sovereignty and law both supported the fixed hierarchical organisation of the previous mode of feudal governmental mechanism, but stripping the modern human subject of any kind of self autonomy; not only fully fit for indoctrination, work, and education a fully fit conversant subject but left them vulnerable as well to face a permanent exam which he(the ordinary individual) had no chance in passing and was supposed to fail with no end point. Foucault maintains that these techniques were deliberate, cold, calculating and ruthless; the human sciences, far from being "a way at looking at the world" the knowledge/power dynamic/relationship Paradigm was a 'cheap' efficient and 'cost' effective method into a way of producing a subjugated and docile human subject (not only a citizen, but a political and productive citizen) as an instrument for administrative control and concern (through the state) for the well being of the population(and a constant help to the spread of biopower) with the help of scientific classifications and new disciplinary technologies including the polity readily available to the human body and mind. Here are a few examples on what Foucault means by this type of "biopower" and bio-history of man
As with the most recent discovery of mirror neurons has demonstrated Foucault has (while these techniques used in Psychiatry and Psychology are not mentioned alongside Foucault's name) hit on something that rigorous research methods may prove beyond a reasonable doubt that manipulation of social phenomena(which includes the human body and the mind) is most certainly possible. Techniques developed from the First and Second World war which started out as field experiments, among military personnel, were then extended into ordinary civilian life; techniques borrowed from the Human cognitive sciences and found its way into Psycho-analysis, Psychiatry, Psychology, Clinical psychology, Lightner Witmer and Clinical psychiatry (see this encyclopedia's article on Political abuse of psychiatry):"Mobilisation and manipulation of human needs as they exist in the consumer". He (Ernest Dichter) "was the first to coin the term focus group and to stress the importance of image and persuasion in advertising". In Vance Packard's book, The Hidden Persuaders Dichter's name is mentioned extensively. Subjectivation, a term Foucault coined for this purpose in which Biological life itself is given over to constant testing and research(an examination) without ever ending. One could argue;who are these new experts answerable too?Foucault argues that these new experts are answerable to absolutely no one. Just like previous notions of the past, absolute monarchy and divine rights of kings were answerable to nobody, their predecessors are just replacements of the past these new experts have now been democratised. Where mans body (and his soul)his mind can be manipulated and altered and is liable to be vulnerable. Every single aspect of the human subject is ripe for 'subjectification' and the technology-as it stands today-is unknown to us. This Biological allegory of man carries with it endless possibilities from the perspective of the Biological sciences and Physical sciences. The above extractions clearly show this "Biopower" of man requires man himself to administer these sophisticated technologies, where one group of experts or professionals(the enquiry) can completely subjugate another producing new human subjects(and new experts) through their expertise at manipulating social phenomena. In these few examples and according to this view:"the criminal is treated like a cancer" whereas human nature does not change which is the only society that ever gets produced, past, present or future.
On The Government Of The Living (1979–1980)
In the On The Government Of The Living lectures delivered in the early months of 1980, Foucault begins to ask questions of Western man obedience to power structures unreservedly and the pressing question of Government: "Government of children, government of souls and consciences, government of a household, of a state, or of oneself." Or governmentality, as Foucault prefers to call it, although he fleshes out the development of that concept in his earlier lectures titled "Security, Territory, Population." Foucault tries to trace the kernel of "the genealogy of obedience" in western society. The 1980 lectures attempt to relate the historical foundations of "our obedience"—which must be understood as the obedience of the Western subject. Foucault argues confessional techniques are an innovation of the Christian West intended to guarantee men's obedience to structures of power in return, so the belief goes, for Christian salvation. In his summary of the course Foucault asks the question: "How is it that within Western Christian culture, the government of men requires, on the part of those who are led, in addition to acts of obedience and submission, 'acts of truth,' which have this particular character that not only is the subject required to speak truthfully but to speak truthfully about himself?" The reader should take note here that much of this kind of work has been done before, albeit in what is best described as brilliant, lost and forgotten scholarship by such scholars as Ernst Kantorowicz (his work on the body politic and the king's two bodies), Percy Ernst Schramm, Carl Erdmann, Hermann Kantorowicz, Frederick Pollock and Frederick Maitland. However, Foucault was after the genealogical dynamics and his main thrust was "regimes of truth" and the emergence and gradual development of "reflexive acts of truth". Foucault locates the very beginning of this act of obedience to power structures and the truth that they bring to the first Christian institutions between the 2nd century and the 5th century C.E. This is where Foucault starts to use his main tool—that is Genealogy as his main focus and it is with this genealogical tool that you finally get to understand fully what genealogy actually means. Foucault goes into great painstaking detail into the Christian baptism and its contingency and discontinuity in order to find "the genealogy of confession". This is an attempt—argues Foucault—to write a "political history of the truth".
Subjectivity and Truth (1980–1981)
In Subjectivity and Truth, Foucault undertakes a deep analysis of sexuality, sexual ethics, and marriage. He looks at the evolving concept of relationships, marriage, and spouses as historical constructs.
The Hermeneutics of the Subject (1981–1982)
In these lectures, Foucault develops notions on the ability of the concept of truth to shift through time as described by the modern human sciences (for example ethnology) in contrast to ancient society (Aristotelian notions). It discusses how these notions are accepted as truth and produce the self as true. This is followed by a discussion on the existence of this truth and the discourse of truth for the experience of the self.
The Government of Self and Others (1982–1983)
The final two years of lectures deal with the concept of parrhesia, translated by Foucault as 'frank speech' and the relationship between the political and the self.
The Courage of Truth (1983–1984)
The last course Foucault gave at the was delayed by illness, for which Foucault received treatment in January 1984. The lectures were ultimately delivered over nine consecutive Wednesdays in February and March of that year. In several of the lectures, Foucault complains of suffering from a bad flu and apologizes for his diminished strength. Although relatively little was known about AIDS at the time, there are several indications that Foucault already suspected he had contracted the virus.
The content of the course expands on the analysis of parrhesia Foucault developed during the previous year, with renewed focus on Plato, Socrates, Cynicism, and Stoicism. On February 15, Foucault delivered a moving lecture on the death of Socrates and the meaning of Socrates' last words. On March 28, twelve weeks before he succumbed to AIDS-related complications, Foucault delivered his final lecture. His last words at the lectern were:
References
External links
Michel Foucault Audio Archive Guide
Michel Foucault
Biopolitics
Political philosophy
Political science
University and college lecture series
Recurring events established in 1970
Books of lectures | Foucault's lectures at the Collège de France | Engineering,Biology | 8,032 |
41,185,806 | https://en.wikipedia.org/wiki/Oil%20Pollution%20Act%20of%201961 | Oil Pollution Act of 1961, 33 U.S.C. Chapter 20 §§ 1001–1011, established judicial definitions and coastal prohibitions for the United States maritime industry. The Act invoked the accords of the International Convention for the Prevention of the Pollution of the Sea by Oil, 1954. The international agreement provided provisions to control the discharge of fossil fuel pollutants from nautical vessels on the high seas.
The S. 2187 legislation was passed by the United States 87th Congressional session and enacted by the 35th President of the United States John F. Kennedy on August 30, 1961.
History
The International Convention for the Prevention of Pollution of the Sea by Oil (OILPOL) was an international convention organized by the United Kingdom in 1954. The convention was held in London, England from April 26, 1954, to May 12, 1954. The international meeting was convened to acknowledge the disposal of harmful waste which posed endangerment to the marine ecosystems.
The International Convention for the Prevention of the Pollution of the Sea by Oil, 1954 original text was penned in English and French. The 1954 international agreement was amended in 1962, 1969, and 1971.
Provisions of the Act
The Act emulated the subsequent formalities of the International Convention for the Prevention of the Pollution of the Sea by Oil, 1954.
Definitions
Discharge in relation to oil or to an oily mixture means any discharge or escape howsoever caused
Heavy diesel oil means marine diesel oil, other than those distillates of which more than fifty percent by volume distils at a temperature not exceeding 340 °C / 644 °F when tested by American Society for Testing and Materials standard method D158-53
Mile means a nautical mile of
Oil means persistent oils, such as crude oil, fuel oil, heavy diesel oil, and lubricating oil. The oil in an oil mixture is less than one hundred parts per one million parts of the oil mixture, and is not deemed to foul the surface of the sea
Prohibited zones means four designated zones described as Adriatic zones, North Sea zones, Atlantic zones, and Australian zone
Ship means
(I) ships for the time being used as naval auxiliaries;
(II) ships of under five hundred tons gross tonnage;
(III) ships for the time being engaged in the whaling industry;
(IV) ships for the time being navigating the Great Lakes of North America and their connecting and tributary waters as far east as the lower exit of the Lachine Canal Montreal in the Province of Quebec, Canada.
Secretary means the Secretary of the United States Army
Zone Prohibitions
Adriatic Zones - Within the Adriatic Sea the prohibited zones off the coasts of Italy and Yugoslavia respectively shall each extend for a distance of from land, excepting only the island of Vis.
North Sea Zones - The North Sea zone shall extend for a distance of from the coasts of the following countries:
Belgium
Denmark
Federal Republic of Germany
Netherlands
United Kingdom of Great Britain and Northern Ireland
but not beyond the point where the limit of a zone off the west coast of Jutland intersects the limit of the zone off the coast of Norway.
Atlantic Zones - Atlantic zone shall be within a line drawn from a point on the Greenwich meridian in a north-north-easterly direction from the Shetland Islands; thence northwards along the Greenwich meridian to latitude 64° north; thence westwards along the 64th parallel to longitude 10° west (); thence to latitude 60° north, longitude 14° west (); thence to latitude 54° 30' north, longitude 30° west (); thence to latitude 44° 20' north, longitude 30° west (); thence to latitude 48° north, longitude 14° west (); thence eastwards along the 48th parallel to a point of intersection with the zone off the coast of France.
Australian Zone - Australian Zone shall extend for a distance of from the coasts of Australia, except off the north and west coasts of the Australian mainland between the point opposite Thursday Island and the point on the west coast at 20° south latitude ().
Oil Record Book
There shall be carried in every ship an oil record book. In the event of such discharge or escape of oil from a ship in a prohibited zone, a signed statement shall be made in the oil record book, by the officer or officers in charge of the operations concerned and by the master of the ship, of the circumstances of and reason for the discharge or escape.
Repeal of Oil Pollution Act of 1961
The 1961 United States statute was repealed by the enactment of Act to Prevent Pollution from Ships on October 21, 1980.
See also
Ballast tank
Ballast water discharge and the environment
Environmental impact of shipping
International Maritime Organization
MARPOL 73/78
Oil discharge monitoring equipment
Oil Pollution Act of 1924
Oil Pollution Act of 1973
Oil Pollution Act of 1990
References
External links
87th United States Congress
1961 in the environment
1961 in American law
Ocean pollution
United States federal environmental legislation | Oil Pollution Act of 1961 | Chemistry,Environmental_science | 982 |
1,133,943 | https://en.wikipedia.org/wiki/Lafayette%20Radio%20Electronics | Lafayette Radio Electronics Corporation was an American radio and electronics manufacturer and retailer from approximately 1931 to 1981, headquartered in Syosset, New York, a Long Island suburb of New York City. The company sold radio sets, Amateur radio (Ham) equipment, citizens band (CB) radios and related communications equipment, electronic components, microphones, public address systems, and tools through their company owned and branded chain of retail outlets and by mail-order.
History
"Wholesale Radio Service" was established in the early 1920s by Abraham Pletman in New York City. Radios sold by the company were trademarked “Lafayette” in July 1931. Following a Federal Trade Commission action in 1935, Wholesale Radio Service became "Radio Wire Television, Inc.". A 1939 company catalog bore the names Radio Wire Television Co. Inc. and "Lafayette Radio Corporation". In 1948, the company issued a catalog under the name “Lafayette-Concord” and called itself the “world’s largest radio supply organization”. In 1952, a catalog was issued using only the Lafayette name.
Lafayette Radio Electronics (LRE) soon became a thriving mail-order catalog business; the electronic components it sold were useful to amateur radio operators and electronic hobbyists in areas where such components were unavailable in local retail outlets. Lafayette's main competitors were Radio Shack, Allied Radio, Heathkit, and "mom and pop" (independent) radio dealers throughout the United States. Early Lafayette Radio stores were located in Jamaica, N.Y. and Manhattan in the mid-1950s. The electronics kits were produced in the Jamaica facility.
Lafayette advertised heavily in major U.S. consumer electronics magazines of the 1960s and 1970s, particularly Audio, High Fidelity, Popular Electronics, Popular Mechanics, and Stereo Review. The company offered a free 400-page catalog filled with descriptions of vast quantities of electronic gear, including microphones, speakers, tape recorders, and other components.
In 1981, Lafayette Radio entered Chapter 11 bankruptcy and sold its New York area stores to Circuit City.
Retail stores
Until the 1960s, many independent retailers in some markets became Lafayette Radio "Associate Stores", which were displaced when the company expanded. These stores were supported from headquarters at 111 Jericho Turnpike in Syosset, NY and a warehouse in Hauppauge, NY. A limited selection of product was stocked, with full access to a catalog with a wide variety of parts, tubes, cameras, musical instruments, kits, gadgets and branded gear that could be ordered and delivered through the local store. The company made major investments in what were called sound rooms to demonstrate hi-fi equipment, using custom switch panels and acoustic treatments in an attempt to duplicate a home listening environment and offer fair comparison with an assortment of branded hi-fi gear.
Managers were rewarded for maximizing gross profit margins and inventory "turns", which led to frequent out-of-stock situations, often remedied by frequent cross-town inter-store transfers. Each store had a repair shop on site with a part-time technician. Some locations had multiple full-time service technicians. Others had service departments that operated independently of the store but under the same ownership. Stores ranged in size from 2,000 to .
By the late 1970s, Lafayette expanded to major markets across the country, struggling to compete with Radio Shack, which was purchased by Tandy Leather Co. in 1963. Lafayette ran into major financial difficulty when the Federal Communications Commission (FCC) expanded a new citizens band radio ("CB") spectrum to 40 channels in 1977. Lafayette's buyers had firm commitments to accept delivery of thousands of older design units capable of only 23 channels, and were not able to liquidate the inventory without taking a serious loss. Eventually, all of the old CB radios were sold for under $40.
With fewer than 100 stores, far fewer than the aggressively expanding Radio Shack's thousands of local outlets, Lafayette Radio remained more of a dedicated enthusiasts' store than a mass marketer. The company was also hurt by the advent of electronics retailers relying on aggressive marketing techniques and competitive pricing in the late 1970s. Many experienced managers departed. The company filed for bankruptcy in 1981 and most Lafayette stores in the state of New York closed by the end of the year. Approximately two thirds of company-owned stores were closed immediately. According to one employee, they were "given 48 hours to tear the entire store down, get everything boxed that had a valid and current stock number, and get it on a truck to take it back to Syosset (Lafayette’s Long Island warehouse). Anything that wasn’t on the official inventory sheets was to be discarded".
In 1981, Lafayette Radio entered Chapter 11 bankruptcy. Several Lafayette stores were purchased by Circuit City of Richmond, Virginia. Of the 150 stores that Lafayette had once owned, eight stores remained when Circuit City took over. In order to keep the Lafayette name, which was popular in New York, Circuit City changed the store names to "Lafayette-Circuit City". However, these store locations were much smaller than a standard Circuit City, and did not carry major appliances, which Circuit City carried at the time. The stores were eventually closed as Circuit City left the New York Market (only to return later). The Syosset repair center was kept open a year after the last store closing to handle warranty coverage. Lafayette-Circuit City used the phrase "no haggling" in its ad campaign, which featured celebrities such as Don King, in trying to demonstrate that the lowest price was always posted, unlike many competitors where you would have to bargain with the sales person for a lower price. This approach, however, did not work, and Lafayette-Circuit City fell due to competition from other New York area electronic retailers such as Newmark and Lewis, Trader Horn, The Wiz, Crazy Eddie, and PC Richard.
As of 2003, the Lafayette brand name was re-launched at the CES show that year. The company's products are offered only through special dealers and limited retail stores.
Products
Lafayette's products ranged from individual resistors, capacitors, and components to stereos and two-way radios for amateur radio, CBers, and shortwave listeners. Many were dedicated types with special functions, such as VHF receivers for police and fire channels built into a CB radio. The company's best selling products were often shortwave receivers, parts, and portable radios. In the 1960s, many Lafayette brand radios were rebranded Trio-Kenwood sets. A significant share of 1960s and 1970s vintage Lafayette hi-fi gear was manufactured by a Japanese subcontractor named "Planet Research". "Criterion" brand speakers were built by several offshore and some domestic assemblers. Science kits were popular, and Lafayette offered the "Novatron", a "Miniature Atom Smasher" (van de Graaff generator), Model F-371.
While the catalog heavily promoted the company's own branded products, Lafayette also carried models from many other hi-fi manufacturers of the era, including Marantz, Fisher, Pioneer, Sansui, AR, Dynaco, KLH, Wharfedale, Bozak, BIC, BSR McDonald, Garrard, Dual, TEAC, Akai, Shure, Empire, Pickering, Electro-Voice, JVC, Panasonic, Sony and others. The catalogs and advertising helped promote the concept of high-fidelity sound to customers, some of whom lived many miles away from major electronics stores, during a time when only the largest urban areas had dedicated "stereo" stores. Lafayette also offered TV vacuum tube testing, for customers who wanted to service their own televisions.
Lafayette was quick to jump on industry trends, first by embracing open reel tape recorders, and later, 8-track cartridge recorders and compact cassette recorders, along with an array of gimmicks, supplies, and accessories. During the mid-1970s, the company's stores were one of few places one could actually experience four channel ("quadraphonic") sound. However the lack of a single industry standard (Columbia SQ vs. JVC's CD-4 and Sansui's QS) dampened sales, and the experiment ended in 1976.
Lafayette also sold a variety of electronic musical equipment made by different manufacturers. There were solid-body and hollow-body electric guitars, probably made by Teisco or Harmony. Microphones, amplifiers, and various electronic effects such as reverbs were available, many of which sported the Lafayette brand name, most notably the Echo Verb and Echo Verb II. Among the most famous guitar effects that Lafayette sold were the Roto-Vibe and Uni-Vibe, used by many musicians, most notably Jimi Hendrix. Robin Trower, and Stevie Ray Vaughan; others later used the effect to emulate Hendrix's sounds and achieve new ones of their own.
Gallery
See also
Allied Electronics
Heathkit
Radio Shack
References
External links
Vintage Lafayette Catalog pages at Early Television
Lafayette Amateur Radio Equipment at RigReference.com
Amateur radio companies
Defunct consumer electronics retailers in the United States
Electronic kit manufacturers
Companies that filed for Chapter 11 bankruptcy in 1981
Companies based in Nassau County, New York
Defunct manufacturing companies based in New York (state)
Radio manufacturers | Lafayette Radio Electronics | Engineering | 1,874 |
7,664,887 | https://en.wikipedia.org/wiki/Fosmid | Fosmids are similar to cosmids but are based on the bacterial F-plasmid. The cloning vector is limited, as a host (usually E. coli) can only contain one fosmid molecule. Fosmids can hold DNA inserts of up to 40 kb in size; often the source of the insert is random genomic DNA. A fosmid library is prepared by extracting the genomic DNA from the target organism and cloning it into the fosmid vector. The ligation mix is then packaged into phage particles and the DNA is transfected into the bacterial host. Bacterial clones propagate the fosmid library.
The low copy number offers higher stability than vectors with relatively higher copy numbers, including cosmids. Fosmids may be useful for constructing stable libraries from complex genomes. Fosmids have high structural stability and have been found to maintain human DNA effectively even after 100 generations of bacterial growth. Fosmid clones were used to help assess the accuracy of the Public Human Genome Sequence.
Discovery
The fertility plasmid or F-plasmid was discovered by Esther Lederberg and encodes information for the biosynthesis of sex pilus to aid in bacterial conjugation. Conjugation involves using the sex pilus to form a bridge between two bacteria cells; this bridge allows the F+ cell to transfer a single-stranded copy of the plasmid so that both cells contain a copy of the plasmid. On the way into the recipient cell, the corresponding DNA strand is synthesized by the recipient. The donor cell maintains a functional copy of the plasmid. It later was discovered that the F factor was the first episome and can exist as an independent plasmid making it a very stable vector for cloning. Conjugation aids in the formation of bacterial clone libraries by ensuring all cells contain the desired fosmid.
Fosmids are DNA vectors that use the F-plasmid origin of replication and partitioning mechanisms to allow cloning of large DNA fragments. A library that provides 20–70-fold redundant coverage of the genome can easily be prepared.
DNA libraries
The first step in sequencing entire genomes is cloning the genome into manageable units of some 50-200 kilobases in length. It is ideal to use a fosmid library because of its stability and limitation of one plasmid per cell. By limiting the number of plasmids in the cells the potential for recombination is decreased, thus preserving the genome insert.
Fosmids contain several functional elements:
OriT (Origin of Transfer): The sequence which marks the starting point of conjugative transfer.
OriV (Origin of Replication): The sequence starting with which the plasmid-DNA will be replicated in the recipient cell.
tra-region (transfer genes): Genes coding the F-Pilus and DNA transfer process.
IS (Insertion Elements): so-called "selfish genes" (sequence fragments which can integrate copies of themselves at different locations).
The methods of cutting and inserting DNA into fosmid vectors have been perfected. There are now many companies that can create a fosmid library from any sample of DNA in a very short period of time at a relatively low cost. This has been vital in allowing researchers to sequence numerous genomes for study. Through a variety of methods, more than 6651 organisms genomes have been fully sequenced, with 58,695 ongoing.
Uses
Sometimes it is difficult to accurately distinguish individual chromosomes based on chromosome length, arm ratio, and C-banding pattern. Fosmids can be used as reliable cytological markers for individual chromosome identification and fluorescent in situ hybridization based metaphase chromosome karyotypes can be used to show whether the positions of these fosmids were successfully constructed.
The fosmid system is excellent for rapidly creating chromosome-specific mini-BAC libraries from flow-sorted chromosomal DNA. The major advantage of Fosmids over other cosmid systems lies in its capability of stably propagating human DNA fragments. Highly repetitive in nature, human DNA is well known for its extreme instability in multicopy vector systems. It has been found that the stability increases dramatically when the human DNA inserts are present in single copies in recombination deficient E. coli cells. Therefore, Fosmids serve as reliable substrates for large scale genomic DNA sequencing.
References
External links
NCBI Nucleotide Database
Cloning
Genomics techniques
Laboratory techniques
Molecular biology techniques | Fosmid | Chemistry,Engineering,Biology | 966 |
25,285,928 | https://en.wikipedia.org/wiki/Space%20research | Space research is scientific study carried out in outer space, and by studying outer space. From the use of space technology to the observable universe, space research is a wide research field. Earth science, materials science, biology, medicine, and physics all apply to the space research environment. The term includes scientific payloads at any altitude from deep space to low Earth orbit, extended to include sounding rocket research in the upper atmosphere, and high-altitude balloons.
Space exploration is also a form of space research.
History
Rockets
Chinese rockets were used in ceremony and as weaponry since the 13th century, but no rocket would overcome Earth's gravity until the latter half of the 20th century. Space-capable rocketry appeared simultaneously in the work of three scientists, in three separate countries. In Russia, Konstantin Tsiolkovsky, in the United States, Robert H. Goddard, and in Germany, Hermann Oberth.
The United States and the Soviet Union created their own missile programs. The space research field evolved as scientific investigation based on advancing rocket technology.
In 1948–1949 detectors on V-2 rocket flights detected x-rays from the Sun. Sounding rockets helped show us the structure of the upper atmosphere. As higher altitudes were reached, space physics emerged as a field of research with studies of Earths aurorae, ionosphere and magnetosphere.
Artificial satellites
The first artificial satellite, Russian Sputnik 1, launched on October 4, 1957, four months before the United States first, Explorer 1. The major discovery of satellite research was in 1958, when Explorer 1 detected the Van Allen radiation belts. Planetology reached a new stage with the Russian Luna programme, between 1959 and 1976, a series of lunar probes which gave us evidence of the Moons chemical composition, gravity, temperature, soil samples, the first photographs of the far side of the Moon by Luna 3, and the first remotely controlled robots (Lunokhod) to land on another planetary body.
International co-operation
The early space researchers obtained an important international forum with the establishment of the Committee on Space Research (COSPAR) in 1958, which achieved an exchange of scientific information between east and west during the cold war, despite the military origin of the rocket technology underlying the research field.
Astronauts
On April 12, 1961, Russian Lieutenant Yuri Gagarin was the first human to orbit Earth, in Vostok 1. In 1961, US astronaut Alan Shepard was the first American in space. And on July 20, 1969, astronaut Neil Armstrong was the first human on the Moon.
On April 19, 1971, the Soviet Union launched the Salyut 1, the first space station of substantial duration, a successful 23 day mission, sadly ruined by transport disasters. On May 14, 1973, Skylab, the first American space station launched, on a modified Saturn V rocket. Skylab was occupied for 24 weeks.
Extent
486958 Arrokoth is the name of the farthest and most primitive object visited by human spacecraft. Originally designated "1110113Y" when detected by Hubble in 2014, the planetessimal was reached by the New Horizons probe on 1 January 2019 after a week long manoeuvering phase. New Horizons detected Ultima Thule from 107 million miles and performed a total 9 days of manoeuvres to pass within 3,500 miles of the 19 mile long contact binary. Ultima Thule has an orbital period around 298 years, is 4.1 billion miles from Earth, and over 1 billion miles beyond Pluto.
Interstellar
The Voyager 1 probe launched on 5 September 1977, and flew beyond the edge of our solar system in August 2012 to the interstellar medium. The farthest human object from the Earth, predictions include collision, an Oort cloud, and destiny, "perhaps eternally—to wander the Milky Way."
Voyager 2 launched on 20 August 1977 travelling slower than Voyager 1 and reached interstellar medium by the end of 2018. Voyager 2 is the only Earth probe to have visited the ice giants of Neptune or Uranus
Neither Voyager is aimed at a particular visible object, but both continue to send research data to NASA Deep Space Network as of 2019.
Two Pioneer probes and the New Horizons probe are expected to enter interstellar medium in the near future, but these three are expected to have depleted available power before then, so the point of exit cannot be confirmed precisely. Predicting probes speed is imprecise as they pass through the variable heliosphere. Pioneer 10 is roughly at the outer edge of the heliosphere in 2019. New Horizons should reach it by 2040, and Pioneer 11 by 2060.
Two Voyager probes have reached interstellar medium, and three other probes are expected to join that list.
Research fields
Space research includes the following fields of science:
Earth observations, using remote sensing techniques to interpret optical and radar data from Earth observation satellites
Geodesy, using gravitational perturbations of satellite orbits
Atmospheric sciences, aeronomy using satellites, sounding rockets and high-altitude balloons
Space physics, the in situ study of space plasmas, e.g. aurorae, the ionosphere, the magnetosphere and space weather
Planetology, using space probes to study objects in the planetary system
Astronomy, using space telescopes and detectors that are not limited by looking through the atmosphere
Materials sciences, taking advantage of the micro-g environment on orbital platforms
Life sciences, including human physiology, using the space radiation environment and weightlessness, also growing Plants in space
Physics, using space as a laboratory for studies in fundamental physics.
Space research from artificial satellites
Upper Atmosphere Research Satellite
Upper Atmosphere Research Satellite was a NASA-led mission launched on September 12, 1991. The satellite was deployed from the Space Shuttle Discovery during the STS-48 mission on 15 September 1991. It was the first multi-instrumented satellite to study various aspects of the Earth's atmosphere and have a better understanding of photochemistry. After 14 years of service, the UARS finished its scientific career in 2005.
Great Observatories program
Great Observatories program is the flagship NASA telescope program. The Great Observatories program pushes forward our understanding of the universe with detailed observation of the sky, based in gamma rays, ultraviolet, x-ray, infrared, and visible, light spectrums. The four main telescopes for the Great Observatories program are, Hubble Space Telescope (visible, ultraviolet), launched 1990, Compton Gamma Ray Observatory (gamma), launched 1991 and retired 2000, Chandra X-Ray Observatory (x-ray), launched 1999, and Spitzer Space Telescope (infrared), launched 2003.
Origins of the Hubble, named after American astronomer Edwin Hubble, go back as far as 1946. In the present day, the Hubble is used to identify exo-planets and give detailed accounts of events in our own solar system. Hubbles visible-light observations are combined with the other great observatories to give us some of the most detailed images of the visible universe.
International Gamma-Ray Astrophysics Laboratory
INTEGRAL is one of the most powerful gamma-ray observatories, launched by the European Space Agency in 2002, and continuing to operate (as of March 2019). INTEGRAL provides insight into the most energetic cosmological formations in space including, black holes, neutron stars, and supernovas. INTEGRAL plays an important role researching gamma-rays, one of the most exotic and energetic phenomena in space.
Gravity and Extreme Magnetism Small Explorer
The NASA-led GEMS mission was scheduled to launch for November 2014. The spacecraft would use an X-Ray telescope to measure the polarization of x-rays coming from black holes and neutron stars. It would research into remnants of supernovae, stars that have exploded. Few experiments have been conducted in X-Ray polarization since the 1970s, and scientists anticipated GEMS to break new ground. Understanding x-ray polarisation will improve scientists knowledge of black holes, in particular whether matter around a black hole is confined, to a flat-disk, a puffed disk, or a squirting jet. The GEMS project was cancelled in June 2012, projected to fail time and finance limits. The purpose of the GEMS mission continues to be relevant (as of 2019).
Space research on space stations
Salyut 1
Salyut 1 was the first space station ever built. It was launched on April 19, 1971 by the Soviet Union. The first crew failed entry into the space station. The second crew was able to spend twenty-three days in the space station, but this achievement was quickly overshadowed since the crew died on reentry to Earth. Salyut 1 was intentionally deorbited six months into orbit since it prematurely ran out of fuel.
Skylab
Skylab was the first American space station. It was 4 times larger than Salyut 1. Skylab was launched on May 14, 1973. It rotated through three crews of three during its operational time. Skylab's experiments confirmed coronal holes and were able to photograph eight solar flares.
Mir
Soviet (later Russian) station Mir, from 1986 to 2001, was the first long term inhabited space station. Occupied in low Earth orbit for twelve and a half years, Mir served a permanent microgravity laboratory. Crews experimented with biology, human biology, physics, astronomy, meteorology and spacecraft systems. Goals included developing technologies for permanent occupation of space.
International Space Station
The International Space Station received its first crew as part of STS-88, in December 1998, an internationally co-operative mission of almost 20 participants. The station has been continuously occupied for , exceeding the previous record, almost ten years by Russian station Mir. The ISS provides research in microgravity, and exposure to the local space environment. Crew members conduct tests relevant to biology, physics, astronomy, and others. Even studying the experience and health of the crew advances space research.
See also
Advances in Space Research (journal)
Benefits of space exploration
Committee on Space Research (COSPAR)
Deep space exploration
Lists of space programs
Outer space
Space Age
Space archaeology
Space architecture
Space exploration
Spacefaring
Space law
Space medicine
Space probe
Space research service (space research radio frequencies)
Space science
References
External links
Research | Space research | Astronomy | 2,063 |
692,369 | https://en.wikipedia.org/wiki/Fractional%20coloring | Fractional coloring is a topic in a young branch of graph theory known as fractional graph theory. It is a generalization of ordinary graph coloring. In a traditional graph coloring, each vertex in a graph is assigned some color, and adjacent vertices — those connected by edges — must be assigned different colors. In a fractional coloring however, a set of colors is assigned to each vertex of a graph. The requirement about adjacent vertices still holds, so if two vertices are joined by an edge, they must have no colors in common.
Fractional graph coloring can be viewed as the linear programming relaxation of traditional graph coloring. Indeed, fractional coloring problems are much more amenable to a linear programming approach than traditional coloring problems.
Definitions
A b-fold coloring of a graph G is an assignment of sets of size b to vertices of a graph such that adjacent vertices receive disjoint sets. An a:b-coloring is a b-fold coloring out of a available colors. Equivalently, it can be defined as a homomorphism to the Kneser graph . The b-fold chromatic number is the least a such that an a:b-coloring exists.
The fractional chromatic number is defined to be:
Note that the limit exists because is subadditive, meaning:
The fractional chromatic number can equivalently be defined in probabilistic terms. is the smallest k for which there exists a probability distribution over the independent sets of G such that for each vertex v, given an independent set S drawn from the distribution:
Properties
We have:
with equality for vertex-transitive graphs,
where n(G) is the order of G, α(G) is the independence number.
Moreover:
where ω(G) is the clique number, and is the chromatic number.
Furthermore, the fractional chromatic number approximates the chromatic number within a logarithmic factor, in fact:
Kneser graphs give examples where: is arbitrarily large, since: while
Linear programming (LP) formulation
The fractional chromatic number of a graph G can be obtained as a solution to a linear program. Let be the set of all independent sets of G, and let be the set of all those independent sets which include vertex x. For each independent set I, define a nonnegative real variable xI. Then is the minimum value of:
subject to:
for each vertex .
The dual of this linear program computes the "fractional clique number", a relaxation to the rationals of the integer concept of clique number. That is, a weighting of the vertices of G such that the total weight assigned to any independent set is at most 1. The strong duality theorem of linear programming guarantees that the optimal solutions to both linear programs have the same value. Note however that each linear program may have size that is exponential in the number of vertices of G, and that computing the fractional chromatic number of a graph is NP-hard. This stands in contrast to the problem of fractionally coloring the edges of a graph, which can be solved in polynomial time. This is a straightforward consequence of Edmonds' matching polytope theorem.
Applications
Applications of fractional graph coloring include activity scheduling. In this case, the graph G is a conflict graph: an edge in G between the nodes u and v denotes that u and v cannot be active simultaneously. Put otherwise, the set of nodes that are active simultaneously must be an independent set in graph G.
An optimal fractional graph coloring in G then provides a shortest possible schedule, such that each node is active for (at least) 1 time unit in total, and at any point in time the set of active nodes is an independent set. If we have a solution x to the above linear program, we simply traverse all independent sets I in an arbitrary order. For each I, we let the nodes in I be active for time units; meanwhile, each node not in I is inactive.
In more concrete terms, each node of G might represent a radio transmission in a wireless communication network; the edges of G represent interference between radio transmissions. Each radio transmission needs to be active for 1 time unit in total; an optimal fractional graph coloring provides a minimum-length schedule (or, equivalently, a maximum-bandwidth schedule) that is conflict-free.
Comparison with traditional graph coloring
If one further required that each node must be active continuously for 1 time unit (without switching it off and on every now and then), then traditional graph vertex coloring would provide an optimal schedule: first the nodes of color 1 are active for 1 time unit, then the nodes of color 2 are active for 1 time unit, and so on. Again, at any point in time, the set of active nodes is an independent set.
In general, fractional graph coloring provides a shorter schedule than non-fractional graph coloring; there is an integrality gap. It may be possible to find a shorter schedule, at the cost of switching devices (such as radio transmitters) on and off more than once.
Notes
References
.
.
See also
Fractional matching
Graph coloring
Fractional graph theory | Fractional coloring | Mathematics | 1,048 |
7,385,565 | https://en.wikipedia.org/wiki/Thue%20number | In the mathematical area of graph theory, the Thue number of a graph is a variation of the chromatic index, defined by and named after mathematician Axel Thue, who studied the squarefree words used to define this number.
Alon et al. define a nonrepetitive coloring of a graph to be an assignment of colors to the edges of the graph, such that there does not exist any even-length simple path in the graph in which the colors of the edges in the first half of the path form the same sequence as the colors of the edges in the second half of the path. The Thue number of a graph is the minimum number of colors needed in any nonrepetitive coloring.
Variations on this concept involving vertex colorings or more general walks on a graph have been studied by several authors including Barát and Varjú, Barát and Wood (2005), Brešar and Klavžar (2004), and Kündgen and Pelsmajer.
Example
Consider a pentagon, that is, a cycle of five vertices. If we color the edges with two colors, some two adjacent edges will have the same color x; the path formed by those two edges will have the repetitive color sequence xx. If we color the edges with three colors, one of the three colors will be used only once; the path of four edges formed by the other two colors will either have two consecutive edges or will form the repetitive color sequence xyxy. However, with four colors it is not difficult to avoid all repetitions. Therefore, the Thue number of C5 is four.
Results
Alon et al. use the Lovász local lemma to prove that the Thue number of any graph is at most quadratic in its maximum degree; they provide an example showing that for some graphs this quadratic dependence is necessary. In addition they show that the Thue number of a path of four or more vertices is exactly three, that the Thue number of any cycle is at most four, and that the Thue number of the Petersen graph is exactly five.
The known cycles with Thue number four are C5, C7, C9, C10, C14, and C17. Alon et al. conjecture that the Thue number of any larger cycle is three; they verified computationally that the cycles listed above are the only ones of length ≤ 2001 with Thue number four. Currie resolved this in a 2002 paper, showing that all cycles with 18 or more vertices have Thue number 3.
Computational complexity
Testing whether a coloring has a repetitive path is in NP, so testing whether a coloring is nonrepetitive is in co-NP, and Manin showed that it is co-NP-complete. The problem of finding such a coloring belongs to in the polynomial hierarchy, and again Manin showed that it is complete for this level.
References
External links
Graph invariants
Graph coloring
Combinatorics on words | Thue number | Mathematics | 599 |
44,358,781 | https://en.wikipedia.org/wiki/Pointr | Pointr is a startup company based in London specialized in indoor positioning and navigation utilising iBeacons, which are Bluetooth Low Energy devices formalised by Apple Inc. Pointr have created a GPS-like experience with true position and turn-by-turn navigation that is supported by most modern smartphones operating on both Android and iOS. Analytics and messaging modules can be added on to help communicate with users and understand venue usage respectively.
The features are provided through a software package (SDK) which aims to improve user experience whilst connecting the online and offline worlds. Many of the features are available without an internet connection, including sending messages between users with a form of Mesh networking, however for intelligent offers and live analytics then an internet connection is required. The markets where the technology is most frequently used are retail, exhibition centres, airports and museums, but there are a number of uses in hospitals, warehouses, offices and entertainment venues as well. The majority of software development is done in their office in Istanbul, with specialist modules created in London. The technology is commonly used in permanent installations where the SDK is offered with a license fee model, however some installations have been temporary and hence one-off payments have been used.
History
Pointr was founded in November 2013 by Ege Akpinar under the name Indoorz; he was then joined by co-founders Axel Katalan, Chris Charles and Can Akpinar in early 2014. The software was developed for seven months before launching, allowing time to build and test the product. In November 2014 the company adopted its current name of Pointr after receiving a client question about whether it could work outdoors as well. Pointr raised its first round of angel funding in January 2015 and has grown steadily with its first customers in retail, warehouses, offices and libraries. In February 2015, Pointr was accepted onto the Microsoft Ventures accelerator program based in Liverpool Street, London. Pointr are also supported by Level 39 (the Fintech Accelerator programme for Canary Wharf Group) and have installed their technology there to locate colleagues and assist new users navigating the venue.
References
External links
2014 software
Android (operating system) software
IOS software
Indoor positioning system | Pointr | Technology | 441 |
15,263,017 | https://en.wikipedia.org/wiki/Deben%20%28unit%29 | The deben was an ancient Egyptian weight unit.
Early Dynastic Period
The earliest evidence for deben is from the Early Dynastic Period. It was found at the site of Buto in Nile Delta. The weighing stone was uncovered in an archaeological context from Second Dynasty, in the so-called "labyrinth" building, it bears the inscription of the "friendly is the heart of Horus, director" (of the installation) "Hemsemenib". The inscribed value is of 3 deben, representing a unit of , likely the earliest copper deben. Based on this evidence, it was argued recently that copper and gold deben were used since Early Dynastic Period in ancient Egypt.
Old and Middle Kingdom
Set of balance beams and weighing stones from 10 to 100 units, likely deben, was painted on the wall of the tomb of Third Dynasty official Hesy-Ra at Saqqara. Stone weights from the Old Kingdom have been found, weighing about , giving presumed value of the gold deben, e.g. the weighing stone of king Userkaf. The same unit was used for the jasper weighing stone of the First Intermediate Period king Nebkaure Khety. From the Middle Kingdom date deben weight units used for particular metals, referred to as copper deben and gold deben, the former being about twice as heavy () as the latter. Such weights from the Middle Kingdom were discovered at Lisht, using gold deben, and copper deben.
Second Intermediate Period
At the Second Intermediate Period site of Tell el-Dab'a were found sets of sphendonoid weighing stones confirming the use of shekel weighing system, both "Syrian" (9-9.5 g) and "Mesopotamian" (c. 8.1-8.5 g). Here presumably stems the changed weighing system of the New Kingdom, with a completely different deben unit.
New Kingdom
From the New Kingdom one deben was equal to about to . It was divided into ten kidet (alt. kit, kite or qedet) of c. to , or into what is referred to by Egyptologists as 'pieces', one twelfth of a deben weighing . It was frequently used to denote value of goods, by comparing their worth to a weight of metal, generally silver or copper. The value of the metal artefacts was expressed by deben, and the weight equalled the value.
Protocurrency
It has been speculated that pieces of metal weighing a deben were kept in boxes, taken to markets, and were used as a means of exchange. Archaeologists have been unable to find any such standardized pieces of precious metal. On the other hand, it is documented that debens served to compare values. On the well-known Juridical stela from the reign of the Sixteenth Dynasty king Nebiryraw I, debt of 60 gold deben (consisting in fact of gold, copper, grain, and clothes as listed on the stela) was worth the governorship of el-Kab. In the 19th Dynasty, a slave girl priced four deben and one kite of silver was paid for with various goods: 6 bronze vessels, 10 deben of copper, 15 linen garments, a shroud, a blanket, and a pot of honey.
Legacy
Deben appeared in the computer game Pharaoh as its currency (in the form of gold).
See also
Ancient Egyptian units of measurement
Egyptian units of measurement
References
Units of mass
Egyptian hieroglyphs | Deben (unit) | Physics,Mathematics | 716 |
40,597,277 | https://en.wikipedia.org/wiki/Vomilenine | Vomilenine is an alkaloid that is an intermediate chemical in the biosynthesis of ajmaline.
References
Tryptamine alkaloids
Quinolizidine alkaloids | Vomilenine | Chemistry | 42 |
22,693,937 | https://en.wikipedia.org/wiki/EDELWEISS | EDELWEISS (Expérience pour DEtecter Les WIMPs En Site Souterrain) is a dark matter search experiment located at the Modane Underground Laboratory in France. The experiment uses cryogenic detectors, measuring both the phonon and ionization signals produced by particle interactions in germanium crystals. This technique allows nuclear recoils events to be distinguished from electron recoil events.
The EURECA project is a proposed future dark matter experiment, which will involve researchers from EDELWEISS and the CRESST dark matter search.
Dark matter
Dark matter is material which does not emit or absorb light. Measurements of the rotation curves of spiral galaxies suggest it makes up the majority of the mass of galaxies; and precision measurements of the cosmic microwave background radiation suggest it accounts for a significant fraction of the density of the Universe.
A possible explanation of dark matter comes from particle physics. WIMP (Weakly Interacting Massive Particle) is a general term for hypothetical particles which interact only through the weak nuclear and gravitational force. This theory suggests our galaxy is surrounded by a dark halo of such particles. EDELWEISS is one of a number of dark matter search experiments aiming to directly detect WIMP dark matter, by detecting the elastic scattering of a WIMP off an atom within a particle detector. As the interaction rate is so low, this requires sensitive detectors, good background discrimination, and a deep underground site (to reduce the background from cosmic rays).
Experiment
EDELWEISS is located in the Modane underground laboratory, in the Fréjus road tunnel between France and Italy, below 1800m of rock. A 20 cm lead shield reduces the gamma background, and a polyethylene shield reduces the neutron flux. All materials close to the detectors are screened for radiopurity. A dilution refrigerator is used to cool the detectors, built in the opposite orientation to most instruments with the detectors at the top and the refrigeration mechanism below.
EDELWEISS uses high purity germanium cryogenic bolometers cooled to 20 milliKelvin above absolute zero. The phonon and ionization signals produced by a particle interaction are measured. This allows background events to be rejected as nuclear recoils events (produced by WIMP or neutron interactions) produce much less ionization than electron recoil events (produced by alpha, beta and gamma radiation). The detectors are similar to those used by the CDMS experiment. Simultaneous detection of ionization and heat with semiconductors at low temperature was an original idea by Lawrence M. Krauss, Mark Srednicki and Frank Wilczek.
A major limitation of early detectors was the problem of surface events. Due to incomplete charge collection, a particle interaction near the surface of the crystal gave no ionization signal, so electron recoils near the surface could be mistaken for nuclear recoils. To avoid this, the collaboration developed new detectors with interdigitised electrodes. Different voltages are applied to a series of electrodes so the direction of electric field is different near the surface of the crystal, allowing over 99.5% of surface events to be rejected.
Results
The results from the first phase of the experiment (EDELWEISS I) were published in 2005, excluding WIMP dark matter with an interaction cross-section above (at ≈85 GeV).
EDELWEISS-II ran 2009–10 with 10 detectors, that is, 4 kg of detector mass (for a total effective exposure of 384 kg·d) limiting high mass
and low mass WIMPs,
and axions. A cross-section of is excluded at 90% C.L. for WIMP mass of 85 GeV. (Just above projected CDMS results in Fig A.)
EDELWEISS-III had 40 detectors. EDELWEISS-III conducted first science run 2014-2015 with results published in 2016.
EURECA design work will continue for operation after the EDELWEISS-III run. It is planned that EURECA would start operating after 2017.
Collaboration
EDELWEISS is a collaboration of the following member institutions:
CEA – Commissariat à l'Énergie Atomique
IRFU - Institut de Recherche sur les Lois Fondamentales de l'Univers
IRAMIS - Institut Rayonnement Matière de Saclay
CNRS – Centre National de la Recherche Scientifique
CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, Orsay
IPNL - Institut de Physique Nucléaire de Lyon
Institut NÉEL, Grenoble
IAS - Institut d'Astrophysique Spatiale, Paris
Institutions outside France
Universität Karlsruhe, Germany
Forschungszentrum Karlsruhe, Germany
JINR – Joint Institute for Nuclear Research, Dubna, Russia
University of Oxford
References
External links
EDELWEISS Collaboration home page
EURECA Collaboration home page
Experiments for dark matter search | EDELWEISS | Physics | 1,004 |
1,662,513 | https://en.wikipedia.org/wiki/Relapse | In internal medicine, relapse or recidivism is a recurrence of a past (typically medical) condition. For example, multiple sclerosis and malaria often exhibit peaks of activity and sometimes very long periods of dormancy, followed by relapse or recrudescence.
In psychiatry, relapse or reinstatement of drug-seeking behavior, is the recurrence of pathological drug use, self harm or other symptoms after a period of recovery. Relapse is often observed in individuals who have developed a drug addiction or a form of drug dependence, as well as those who have a mental disorder.
Risk factors
Dopamine D2 receptor availability
The availability of the dopamine receptor D2 plays a role in self-administration and the reinforcing effects of cocaine and other stimulants. The D2 receptor availability has an inverse relationship to the vulnerability of reinforcing effects of the drug. With the D2 receptors becoming limited, the user becomes more susceptible to the reinforcing effects of cocaine. It is currently unknown if a predisposition to low D2 receptor availability is possible; however, most studies support the idea that changes in D2 receptor availability are a result, rather than a precursor, of cocaine use. It has also been noted that D2 receptors may return to the level existing prior to drug exposure during long periods of abstinence, a fact which may have implications in relapse treatment.
Social hierarchy
Social interactions, such as the formation of linear dominance hierarchies, also play a role in vulnerability to substance use. Animal studies suggest that there exists a difference in D2 receptor availability between dominant and subordinate animals within a social hierarchy as well as a difference in the function of cocaine to reinforce self-administration in these animal groups. Socially dominant animals exhibit higher availability of D2 receptors and fail to maintain self-administration.
Triggers
Drug taking and relapse are heavily influenced by a number of factors including the pharmacokinetics, dose, and neurochemistry of the drug itself as well as the drug taker’s environment and drug-related history. Reinstatement of drug use after a period of non-use or abstinence is typically initiated by one or a combination of the three main triggers: stress, re-exposure to the drug or drug-priming, and environmental cues. These factors may induce a neurochemical response in the drug taker that mimics the drug and thus triggers reinstatement. These cues may lead to a strong desire or intention to use the drug, a feeling termed craving by Abraham Wikler in 1948. The propensity for craving is heavily influenced by all three triggers to relapse and is now an accepted hallmark of substance dependence. Stress is one of the most powerful stimuli for reinstating drug use because stress cues stimulate craving and drug-seeking behavior during abstinence. Stress-induced craving is also predictive of time to relapse. Comparably, addicted individuals show an increased susceptibility to stressors than do non-addicted controls. Examples of stressors that may induce reinstatement include emotions of fear, sadness, or anger, a physical stressor such as a footshock or elevated sound level, or a social event. Drug-priming is exposing the abstinent user to the addictive substances, which will induce reinstatement of the drug-seeking behavior and drug self-administration. Stimuli that have a pre-existing association with a given drug or with use of that drug can trigger both craving and reinstatement. These cues include any items, places, or people associated with the drug.
Treatment
Relapse treatment is somewhat of a misnomer because relapse itself is a treatment failure; however there exist three main approaches that are currently used to reduce the likelihood of drug relapse. These include pharmacotherapy, cognitive behavioral techniques, and contingency management. The main goals of treating substance dependence and preventing relapse are to identify the needs that were previously met by use of the drug and to develop the skills needed to meet those needs in an alternative way.
Pharmacotherapy
''Related article: Drug rehabilitation
Various medications are used to stabilize an addicted user, reduce the initial drug use, and prevent reinstatement of the drug. Medications can normalize the long-term changes that occur in the brain and nervous system as a result of prolonged drug use. This method of therapy is complex and multi-faceted because the brain target for the desire to use the drug may be different from the target induced by the drug itself. The availability of various neurotransmitter receptors, such as the dopamine receptor D2, and changes in the medial prefrontal cortex are prominent targets for pharmacotherapy to prevent relapse because they are heavily linked to drug-induced, stress-induced, and cue-induced relapse. Receptor recovery can be upregulated by administration of receptor antagonists, while pharmacotherapeutic treatments for neruoadaptations in the medial prefrontal cortex are still relatively ineffective due to lacking knowledge of these adaptations on the molecular and cellular level.
Cognitive behavioral techniques
The various behavioral approaches to treating relapse focus on the precursors and consequences of drug-taking and reinstatement. Cognitive-behavioral techniques (CBT) incorporate Pavlovian conditioning and operant conditioning, characterized by positive reinforcement and negative reinforcement, in order to alter the cognitions, thoughts, and emotions associated with drug-taking behavior. A main approach of CBT is cue exposure, during which the abstinent user is repeatedly exposed to the most salient triggers without exposure to the substance in hopes that the substance will gradually lose the ability to induce drug-seeking behavior. This approach is likely to reduce the severity of a relapse than to prevent one from occurring altogether. Another method teaches addicts basic coping mechanisms to avoid using the illicit drug. It is important to address any deficits in coping skills, to identify the needs that likely induce drug-seeking, and to develop another way to meet them.
Relapse prevention
Relapse prevention attempts to group the factors that contribute to relapse into two broad categories: immediate determinants and covert antecedents. Immediate determinants are the environmental and emotional situations that are associated with relapse, including high-risk situations that threaten an individual’s sense of control, coping strategies, and outcome expectancies. Covert antecedents, which are less obvious factors influencing relapse, include lifestyle factors such as stress level and balance, and urges and cravings. The relapse prevention model teaches addicts to anticipate relapse by recognizing and coping with various immediate determinants and covert antecedents. The RP model shows the greatest success with treatment of alcoholism but it has not been proven superior to other treatment options. Relapse may also be more likely to occur during certain times, such as the holiday season when stress levels are typically higher. So, emphasizing relapse prevention strategies during these times is ideal.
Contingency management
In contrast to the behavioral approaches above, contingency management concentrates on the consequences of drug use as opposed to its precursors. Addict behavior is reinforced, by reward or punishment, based on ability to remain abstinent. A common example of contingency management is a token or voucher system, in which abstinence is rewarded with tokens or vouchers that individuals can redeem for various retail items.
Animal models
There are vast ethical limitations in drug addiction research because humans cannot be allowed to self-administer drugs for the purpose of being studied. However, much can be learned about drugs and the neurobiology of drug taking by the examination of laboratory animals. Most studies are performed on rodents or non-human primates with the latter being most comparable to humans in pharmacokinetics, anatomy of the prefrontal cortex, social behavior, and life span. Other advantages to studying relapse in non-human primates include the ability of the animal to reinstate self-administration, and to learn complex behaviors in order to obtain the drug. Animal studies have shown that a reduction in negative withdrawal symptoms is not necessary to maintain drug taking in laboratory animals; the key to these studies is operant conditioning and reinforcement.
Protocols
Self-administration
To self-administer the drug of interest the animal is implanted with an intravenous catheter and seated in a primate chair equipped with a response lever. The animal is seated in a ventilated chamber and trained on a schedule of drug self-administration. In many studies the self-administration task begins with presentation of a stimulus light (located near the response panel) that may change colors or turn off upon completion of the operant task. The change in visual stimulus is accompanied by an injection of the given drug through the implanted catheter. This schedule is maintained until the animals learn the task.
Extinction
Extinction in non-human primates is analogous, with some limitations, to abstinence in humans. In order to extinguish drug-seeking behavior the drug is substituted with a saline solution. When the animal performs the task it has been trained to perform it is no longer reinforced with an injection of the drug. The visual stimulus associated with the drug and completion of the task is also removed. The extinction sessions are continued until the animal ceases the drug-seeking behavior by pressing the lever.
Reinstatement
After the animal’s drug-seeking behavior is extinguished, a stimulus is presented to promote the reinstatement of that same drug-seeking behavior (i.e., relapse). For example, if the animal receives an injection of the drug in question it will likely begin working on the operant task for which it was previously reinforced. The stimulus may be the drug itself, the visual stimulus that was initially paired with the drug intake, or a stressor such as an acoustic startle or foot shock. However, the stimulus used to trigger reinstatement can influence the psychological processes involved.
Neuroimaging
Neuroimaging has contributed to the identification of the neural components involved in drug reinstatement as well as drug-taking determinants such as the pharmokinetics, neurochemistry, and dose of the drug. The neuroimaging techniques used in non-human primates include positron emission tomography (PET), which uses radiolabeled ligand tracers to measure neurochemistry in vivo and single-photon emission computed tomography (SPECT). Functional magnetic resonance imaging (fMRI) is widely used in human subjects because it has much higher resolution and eliminates exposure to radiation.
Limitations
Although the reinstatement protocols are used frequently in laboratory settings there are some limitations to the validity of the procedures as a model of craving and relapse in humans. The primary limiting factor is that in humans, relapse rarely follows the strict extinction of drug-seeking behavior. Additionally, human self-reports show that drug-associated stimuli play a lesser role in craving in humans than in the laboratory models. The validity of the model can be examined in three ways: formal equivalence, correlational models, and functional equivalence. There is moderate formal equivalence, or face validity, meaning that the model somewhat resembles relapse as it occurs outside of the laboratory setting; however, there is little face validity for the procedures as a model of craving. The predictive validity, which is assessed by correlational models, has yet to be determined for the procedures. There is sound functional equivalence for the model, which suggests that relapse in the laboratory is reasonably similar to that in nature. Further research into other manipulations or reinforcements that could limit drug-taking in non-human primates would be extremely beneficial to the field.
Differences between sexes
There exists a higher rate of relapse, shorter periods of abstinence, and higher responsiveness to drug-related cues in women as compared to men. One study suggests that the ovarian hormones, estradiol and progesterone, that exist in females at fluctuating levels throughout the menstrual cycle (or estrous cycle in rodents), play a significant role in drug-primed relapse. There is a marked increase in progesterone levels and a decrease in estradiol levels during the luteal phase. Anxiety, irritability, and depression, three symptoms of both withdrawal and the human menstrual cycle, are most severe in the luteal phase. Symptoms of withdrawal not associated with the cycle, such as hunger, are also enhanced during the luteal phase, which suggests the role of estradiol and progesterone in enhancing symptoms above the naturally occurring level of the menstrual cycle. The symptoms of craving also increase during the luteal phase in humans (it is important to note that the opposite result occurs in female subjects with cocaine addiction suggesting that cyclic changes may be specific for different addictive substances). Further, the drug-primed response is decreased during the luteal phase suggesting a time in the cycle during which the urge to continue use may be reduced. These findings implicate a cyclic, hormone-based timing for quitting an addictive substance and preparing for magnified symptoms of withdrawal or susceptibility to relapse.
See also
Substance use disorder
National Institute on Drug Abuse
References
Behavioral neuroscience
Addiction
Substance dependence
Substance-related disorders
de:Rezidiv
ru:Рецидив (медицина) | Relapse | Biology | 2,793 |
50,408,821 | https://en.wikipedia.org/wiki/C12orf42 | Chromosome 12 Open Reading Frame 42 (C12orf42) is a protein-encoding gene in Homo sapiens.
Gene
Locus
The genomic location for this gene is as follows: starts at 103,237,591 bp and ends 103,496,010 bp. The cytogenetic location for C12orf42 is 12q23.2. It is located on the negative strand
mRNA
Fifteen different mRNAs are made by transcription: fourteen alternative splice variants and one unspliced form.
Protein
The protein released by this gene is known as uncharacterized protein C12orf42. There are three isoforms for this protein produced by alternative splicing. The first isoform is a conical sequence. The second Isoform differs form the first in that it doesn't contain 1-95 aa in its sequence. The third isoform differs from the conical sequence in two ways:
87-107 aa is the sequence GSHHGQATQKLQGAMVLHLEE instead of VFPERTQNSMACKRLLHTCQY
the entire sequence 108-360 aa doesn't exist in this isoform
Secondary structure
C12orf42 protein takes on several secondary structures, such as: alpha helices, beta sheets, and random coils. C12orf42 protein is a soluble. Proteins that are soluble have a hydrophilic outside and hydrophobic interior . Proteins with this type of structure are able to freely float inside a cell, due to the liquid composition of the cytosol.
Subcellular location
C12orf42 is an intracellular protein. This is known by the lack of transmembrane domains or signal peptides. This suggests that it is predicted to be a nuclear protein, given the nuclear localization signal (NSL) found: PRDRRPQ at 292 aa and a bipartite KRLIKVCSSAPPRPTRR at 325 aa.
Post-translation modification
Predicted post-translation modification sites are seen below in the table. Nuclear proteins are known for having phosphorylation, acetylation, sumoylation, and O-GlcNAc as types of modifications:
Phosphorylation affects proteins-protein interaction and the stability of the protein.
Acetylation promotes protein folding and improves stability.
Sumoylation is involved in nuclear-cytosolic transport and DNA repair.
Glycosylation (known as O-GlcNAc while in the nucleus) promotes protein folding and stability.
Expression
Tissue profiles
Microarray data shows expression of the C12orf42 gene in different tissues throughout the human body. There is high expression in the lymph node, spleen, and thymus. There is significant expression in the brain, bladder, epididymis, and the helper T cell. Therefore, there is statistically significant expression of C12orf42 gene throughout the nervous system, immune system, and male reproductive system.
In situ hybridization
The table below shows the areas in the mouse brain where C12orf42 is expressed. The gene name for the mouse is 1700113H08Rik, it is the human homolog of C12orf42. Area one and two of the brain manages body and skeletal movement. Areas three and four in the brain are for sensory functions; area four specializes in perception of smell. Area five in the brain functions in emotional learning and memory.
Homology
Paralog
C12orf42 gene has only one other member in its gene family, this gene is known as Neuroligin 4, Y linked gene (NLGN4Y).
Orthologs
C12orf42 orthologs are mostly mammals. One exception that was found is the Pelodiscus Sinensis or more commonly known as the Chinese soft-shell turtle.
Conserved domain structure
The domain structure that is most important is DUF4607, it is conserved in the Eutheria clade in the Mammalia class. The order that it is conserved in is as follows: Artiodactyla, Carnivora, Chiroptera, Lagomorpha, Perissodactyla, Primates, Proboscidea, and Rodentia.
Clinical significance
In an experiment, fine-tiling comparative genomic hybridization (FT-CGH) and ligation-mediated PCR (LM-PCR) were combined. This resulted in the finding of a chromosomal translocation t(12;14)(q23;q11.2) in T-lymphoblastic lymphoma (T-LBL). The chromosomal translocation occurs during T-receptor delta gene-deleting rearrangement, which is important in T-cell differentiation. This translocation disrupts C12orf42 and it brings the gene ASCL1 closer to the T-cell receptor alpha (TRA) enhancer. As a result, the cross-fused gene encodes vital transcription factors that are found in medullary thyroid cancer and small-cell lung cancer.
References
Genes
Proteins | C12orf42 | Chemistry | 1,040 |
5,481,991 | https://en.wikipedia.org/wiki/PSR%20J0537%E2%88%926910 | |- style="vertical-align: top;"
| Distance
| 170,000 ly
PSR J0537-6910 is a pulsar that is 4,000 years old (not including the light travel time to Earth). It is located about 170,000 light-years away, in the southern constellation of Dorado, and is located in the Large Magellanic Cloud. It rotates at 62 hertz.
A team at LANL advanced that it is possible to predict starquakes in J0537-6910, meaning that it may be possible to devise a way to forecast glitches at least in some exceptional pulsars. The same team observed magnetic pole drift on this pulsar with observational data from Rossi X-ray Timing Explorer.
References
External links
Scientists Can Predict Pulsar Starquakes (SpaceDaily) Jun 07, 2006
SIMBAD entry for PSR J0537-6910
See also
Supernova
LHA 120-N 157B
Stars in the Large Magellanic Cloud
Dorado
Pulsars | PSR J0537−6910 | Astronomy | 224 |
1,222,444 | https://en.wikipedia.org/wiki/Thorleif%20Schjelderup-Ebbe | Thorleif Schjelderup-Ebbe (12 November 1894 in Kristiania – 8 June 1976 in Oslo) was a Norwegian zoologist and comparative psychologist. He was the first person to describe a pecking order of hens.
Life and work
Thorleif Schjelderup-Ebbe the son of sculptors (1868–1941) and Menga Schjelderup (1871–1945). At the age of 19, in 1913, he described a pecking order of hens. The findings were based on observing chickens at a farm during his summer holidays. The dominance hierarchy of chickens and other birds that he studied led him to the observation that hens had an established social order determining who-dared-to-peck-whom in a fight. This order was, Schjelderup-Ebbe concluded, not necessarily dependent on the strength or age of the hens, and not necessarily a strict ranking as he even observed triangles of dominance. Schjelderup-Ebbe studied for a Ph.D. in Germany, tried to present his thesis in Oslo, but was rejected.
Personal life
Schjelderup-Ebbe was married to Torbjørg Brekke. Their son was Dag Schjelderup-Ebbe, a musicologist, composer, music critic and biographer.
Publications
Hønsenes stemme. Bidrag til hønsenes psykologi, in: Naturen: populærvitenskapeling tidsskrift 37, 1913, 262–276
Kometen: mytisk roman, Kristiania 1917
Beiträge zur Biologie und Sozial- und Individualpsychologie bei Gallus domesticus, Greifswald 1921
Gallus domesticus in seinem täglichen Leben, Dissertation Universität Greifswald, 12 May 1921
Beiträge zur Sozialpsychologie des Haushuhns, in: Zeitschrift für Psychologie 88, 1922, 225–252
Soziale Verhältnisse bei Vögeln, in: Zeitschrift für Psychologie 90, 1922, 106–107
Aufmerksamkeit bei Mücken und Fliegen, in: Zeitschrift für Psychologie 93, 1923, 281-282
Beiträge zur Analyse der Träume, in: Zeitschrift für Psychologie 93, 1923, 312-318
Digte, Kristiania 1923
Der Graupapagei in der Gefangenschaft, in: Psychologische Forschung 3, 1923, 9–11
Das Leben der Wildente in der Zeit der Paarung, in: Psychologische Forschung 3, 1923, 12–17
Tanker og aforismer, Kristiania 1923
Weitere Beiträge zur Sozialpsychologie des Haushuhns, in: Zeitschrift für Psychologie 92, 1923, 60–87
Aufmerksamkeit bei Mücken und Fliegen, in: Entomologische Zeitschrift 1924, 38 (October 18), 31-32
Beobachtungen an Gryllus campestris, in: Entomologische Zeitschrift 1924, 38 (October 18), 31
Biologische Eigentümlichkeiten bei Insekten, in: Entomologische Zeitschrift 1924, 38 (November 1), 41-42
Fortgesetzte biologische Beobachtungen bei Gallus domesticus, in: Psychologische Forschung 5, 1924, 343–355
Kurzgefaßte norwegische Grammatik, Teil 1: Lautlehre, Berlin 1924
Les Despotisme chez les oiseaux, in: Bulletin de l'Institut Général Psychologique 24, 1924, 1–74
Poppelnatten: digte, Kristiania 1924
Schaukeln bei Mücken, in: Entomologische Zeitschrift 1924, 38 (November 29), 52
Zur Sozialpsychologie der Vögel, in: Zeitschrift für Psychologie 95, 1924, 36–84
Aufmerksamkeit bei Käfern, in: Entomologische Zeitschrift 38, 1925 (February 28), 93-94
Det nye eventyr: digte, Oslo 1925
Soziale Verhältnisse bei Säugetieren, in: Zeitschrift für Psychologie 97, 1925, 145
Zur Theorie der Mengenlehre, in: Annalen der Philosophie und philosophischen Kritik 5, 1925/1926, 325–328
Blaat og rødt: digte, Oslo 1926
Der Kontrast auf dem Gebiete des Licht- und Farbensinnes, in: Neue Psychologische Studien 2, 1926, 61–126
Sociale tilstande hos utvalgte inferiore vesner, in: Arkiv för psykologi och pedagogik 5, 1926, 105–220
Organismen und Anorganismen, in: Annalen der Philosophie und philosophischen Kritik 6, 1927, 294–296
Fra billenes verden, Oslo 1928
Overhöihetsformer i den menneskelige sociologi, in: Arkiv för Psykologi och Pedagogik 8, 1929, 53–100
Zur Psychologie der Zahleneindrücke, in: Kwartalnik Psychologiczny 1, 1930, 365–380
Psychologische Beobachtungen an Vögeln, in: Zeitschrift für Angewandte Psychologie 35, 1930, 362–366
Die Despotie im sozialen Leben der Vögel, in: Richard Thurnwald (ed.), Forschungen zur Völkerpsychologie und Soziologie 10, 1931, 77–137
Farben-, Helligkeits-, und Sättigungskontraste bei mitteleuropäischen Käfern, in: Archiv für die Gesamte Psychologie 78, 1931, 571–573
Liljene på marken, Oslo 1931
Soziale Eigentümlichkeiten bei Hühnern, in: Kwartalnik Psychologiczny 2, 1931, 206–212
Instinkte und Reaktionen bei Pfauen und Truthühnern, in: Kwartalnik Psychologiczny 3, 1932, 204–207
Social behavior of birds, in: Carl Murchison (ed.), A Handbook of Social Psychology, Worcester 1935, 947–972
Über die Lebensfähigkeit alter Samen, Oslo 1936
Sanger og strofer, Oslo 1949
Hva verden sier: en lyrisk, satirisk og virkelighetstro diktsyklus, Oslo 1953
Liv, reaksjoner og sociologi hos en flerhet insekter, Oslo 1953
Glansen og det skjulte: lyrikk, humor og satire, Oslo 1955
Høider og dybder: lyrikk, humor og satire, Oslo 1957
Life, reactions, and sociology in a number of insects, in: The Journal of Social Psychology, 46, 1957, 287–292
Sozialpsychologische Analogien bei Menschen und Tier, in: Deutsche Gesellschaft für Psychologie, Bericht über den 22. Kongress der Deutschen Gesellschaft für Psychologie in Heidbelberg 1959, Göttingen 1960, 237–249
Sol og skygge: aforismer og tanker, Oslo 1965
Av livets saga: tanker, vers og shortstories, Oslo 1966–1969
Noen nyere undersøkelser om estetikk, særlig m.h.t. diktning og folklore, Oslo 1967
Notes
Further reading
Charles W. Leland, Thorleif Schjelderup-Ebbe: Sanger og strofer (Book Review), in: Scandinavian Studies 23, 1951, 208–213
Charles W. Leland, Thorleif Schjelderup-Ebbe's "Hva verden sier" (Book Review), in: Scandinavian Studies 27, 1955, 206–212
John Price, A Remembrance of Thorleif Schjelderup-Ebbe, in: Human Ethology Bulletin 1995, 10(1), 1-6 PDF(contains an interview with Th. Schjelderup-Ebbe's son, musicologist Dag Schjelderup-Ebbe)
Wilhelm Preus Sommerfeldt, Professor dr. Thorleif Schjelderup-Ebbes forfatterskap 1910–1956, Oslo 1957
External links
Theme issue of Philosophical Transactions B on 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'
Online edition of the Human Ethology Bulletin
Thorleif Schjelderup-Ebbe at Norske Biografisk Leksikon
1894 births
1976 deaths
20th-century Norwegian zoologists
Scientists from Oslo | Thorleif Schjelderup-Ebbe | Biology | 1,927 |
6,612,910 | https://en.wikipedia.org/wiki/Phytotoxicity | Phytotoxicity describes any adverse effects on plant growth, physiology, or metabolism caused by a chemical substance, such as high levels of fertilizers, herbicides, heavy metals, or nanoparticles. General phytotoxic effects include altered plant metabolism, growth inhibition, or plant death. Changes to plant metabolism and growth are the result of disrupted physiological functioning, including inhibition of photosynthesis, water and nutrient uptake, cell division, or seed germination.
Fertilizers
High concentrations of mineral salts in solution within the plant growing medium can result in phytotoxicity, commonly caused by excessive application of fertilizers. For example, urea is used in agriculture as a nitrogenous fertilizer. However, if too much is applied, phytotoxic effects can result from urea toxicity directly or ammonia production from hydrolysis of urea. Organic fertilizers, such as compost, also have the potential to be phytotoxic if not sufficiently humified, as intermediate products of this process are harmful to plant growth.
Herbicides
Herbicides are designed and used to control unwanted plants such as agricultural weeds. However, the use of herbicides can cause phytotoxic effects on non-targeted plants through wind-blown spray drift or from the use of herbicide-contaminated material (such as straw or manure) being applied to the soil. Herbicides can also cause phytotoxicity in crops if applied incorrectly, in the wrong stage of crop growth, or in excess. The phytotoxic effects of herbicides are an important subject of study in the field of ecotoxicology.
Heavy Metals
Heavy metals are high-density metallic compounds which are poisonous to plants at low concentrations, although toxicity depends on plant species, specific metal and its chemical form, and soil properties. The most relevant heavy metals contributing to phytotoxicity in crops are silver (Ag), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn). Of these, Co, Cu, Fe, Ni, and Zn are trace elements required in small amounts for enzyme and redox reactions essential in plant development. However, past a certain threshold they become toxic. The other heavy metals listed are considered toxic at any concentration and can bioaccumulate, posing a health hazard to humans if consumed.
Heavy metal contamination occurs from both natural and anthropogenic sources. The most notable natural source of heavy metals is rock outcroppings, although volcanic eruptions can release large amounts of toxic material. Significant anthropogenic sources include mining and smelting operations and organic and inorganic fertilizer application.
Nanoparticles
Nanotechnology is a rapidly growing industry with many applications, including drug delivery, biomedicines, and electronics. As a result, manufactured nanoparticles, with sizes less than 100 nm, are released into the environment. Plant uptake and bioaccumulation of these nanoparticles can cause plant growth enhancement or phytotoxic effects, depending on plant species and nanoparticle concentration.
References
Wikipedia Student Program
Agricultural chemicals
Pesticides
Toxicology | Phytotoxicity | Biology,Environmental_science | 680 |
18,277,696 | https://en.wikipedia.org/wiki/Allion%20Healthcare | Allion Healthcare Inc. was the parent company of MOMSpharmacy based in Melville, New York primarily known for providing mail order HIV medications to patients who are primarily on Medicaid or the AIDS Drug Assistance Program (ADAP).
Among the offerings is the MOMSPak in which the drugs are packed together in dated individual packages to make the multi-drug regimen easier.
The company has distribution centers in New York, California, Florida, New Jersey, and Washington.
History
The company was founded in 1983 as The Care Group and changed its name to Allion in 1999 after emerging from bankruptcy.
The company has an agreement with Roche Laboratories for pricing discounts in exchange for providing blind patient data on Fuzeon medication. In November 2007 Company signed an exclusive distribution agreement with Galea Life Sciences for Nutraplete, the first therapeutic dietary supplement designed specifically for people living with HIV/AIDS.
The company was listed on NASDAQ on the ticker symbol ALLI. In October 2009, the company was acquired by the private equity firm HIG Capital for $6.60/share in a deal valued at $278 million.
The MOMS Pharmacy division of Allion Healthcare was acquired by the AIDS Healthcare Foundation in 2012.
2012 indictment
On April 4, 2012, the New York Attorney General Eric T. Schneiderman charged four people associated with the company in a Money Laundering & Bribery Scheme claiming the company sold blackmarket drugs "of unknown origin and potency, and in some cases, drugs that were mislabeled or potentially expired." According to the complaint: To date none of such has been proven.
In September 2008, Glenn Schabel, the supervising pharmacist and compliance officer for Allion, began ordering in excess of $274 million worth of alleged black market HIV medications from various licensed wholesalers over a 4 year period as directed by executive management. The Attorney General claimed such medications were obtained by various illegal means and the batches may have included unused pills that had previously been dispensed to individuals, medications stolen from manufacturers, or drugs that had expired, even though they were provided in legitimate manufacturers bottles. None of these claims have been proven to date even after hundreds of bottles were analyzed. The wholesalers were controlled by Stephen Manuel Costa, a 27-year-old Florida resident who incorporated four separate entities as licensed “wholesale” distributors, allegedly in order to disguise the sale of the diverted medications. It is also alleged that Costa furnished millions of the black market HIV medications to various entities including MOMS who dispensed the medications to their patients, many of whom were Medicaid recipients. Allion, under the direction of corporate management, continued to bill Medicaid, claiming no knowledge that the drugs were purchased illegally.
Attorney General Schneiderman’s investigation also revealed that Ira Gross, another licensed pharmacist, brokered the sale of the alleged illegally diverted drugs between Allion and Costa. The fourth defendant, Harry Abolafia, created false invoices for Costa’s companies—SMC Distributors, Fidelity Wholesale, Optimus Wholesale, and Nuline Pharmaceuticals—in order to make the transactions appear to be legitimate. In total, on behalf of Allion, Schabel ordered $274 million worth of alleged black market HIV medications from Costa's licensed wholesalers.
The indictment said at least $155 million in false claims were associated with the charge.
References
External links
Momspharmacy.com
allionhealthcare.com
Medicare Video Guide
American companies established in 1983
Health care companies established in 1983
Companies that filed for Chapter 11 bankruptcy in 1999
HIV/AIDS in the United States
Medicare and Medicaid (United States)
Companies based in Suffolk County, New York
Pharmacy benefit management companies based in the United States
Health care companies based in New York (state)
1983 establishments in New York (state)
Companies formerly listed on the Nasdaq
2010 mergers and acquisitions
Specialty drugs
Private equity portfolio companies | Allion Healthcare | Biology | 801 |
66,290,561 | https://en.wikipedia.org/wiki/Shabir%20Madhi | Shabir Ahmed Madhi, (born 1966) is a South African physician who is professor of vaccinology and director of the South African Medical Research Council Respiratory and Meningeal Pathogens Research Unit at the University of the Witwatersrand, and National Research Foundation/Department of Science and Technology Research Chair in Vaccine Preventable Diseases. In January 2021, he was appointed Dean of the Faculty of Health Sciences at the University of the Witwatersrand.
Madhi was executive director of South Africa's National Institute for Communicable Diseases from 2011 to 2017, and has served on several WHO committees in roles pertinent to vaccines and pneumonia. In 2018, he co-founded the African Leadership in Vaccinology Expertise (ALIVE) and was appointed Chair of South Africa's National Advisory Group on Immunization (NAGI). His research has included studies on the pneumococcal conjugate vaccine and rotavirus vaccine, and in pregnant women, the influenza and respiratory syncytial virus vaccines.
Since the global COVID-19 pandemic in 2020, Madhi has been leading COVID-19 vaccine trials in South Africa, including the first in Africa. In 2021 he stated that the first and foremost method of ending COVID-19 in South Africa is to implement a mass vaccination programme.
Early life and education
Madhi was born in 1966. His father was a teacher and mother a housewife. Initially aspiring to becoming an engineer, he opted to accept a bursary to study medicine and was initially reluctant to persist with his medical education. In 1990 he completed his undergraduate and postgraduate training at the University of the Witwatersrand, Johannesburg, and six years later, became a fellow of the College of Paediatrics (FCPaeds (SA)). During this time, with encouragement from Glenda Gray, he applied for a post under professor Keith Klugman, to work on vaccines for pneumonia.
In 1998 he received a master's degree in medicine (paediatrics). He gained his PhD in 2003.
Career
Madhi is professor of vaccinology and director of the South African Medical Research Council Respiratory and Meningeal Pathogens Research Unit at the University of the Witwatersrand, and National Research Foundation/Department of Science and Technology Research Chair in Vaccine Preventable Diseases. These units have been rebranded as the MRC Vaccines and Infectious Diseases Analytics Research Unit (VIDA).
He was executive director of South Africa's National Institute for Communicable Diseases from 2011 to 2017, and has served on several WHO committees in roles pertinent to vaccines and pneumonia. In 2018, after spending four years as deputy-chair of South Africa's National Advisory Group on Immunization (NAGI), he became its chairperson. In the same year he co-founded the African Leadership in Vaccinology Expertise (ALIVE), based at the University of the Witwatersrand, with the aim of expanding expertise in vaccinology in Africa. In January 2021, he became Dean of the Faculty of Health Sciences of the University of the Witwateratand.
Pneumonia vaccine
His research has included studies on the pneumococcal conjugate vaccine. This research led to the WHO recommendations on the delivery of this vaccine in low and middle-income countries.
Rotavirus vaccine
Madhi led the first study that showed that a rotavirus vaccine could significantly prevent severe diarrhoea due to rotavirus during the first year of life in African babies. It was published in The New England Journal of Medicine in 2010. The paper provided one of the key pieces of evidence for the WHO recommendations of universal rotavirus vaccination.
Flu vaccine
In pregnant women, he studied the effectiveness of influenza and respiratory syncytial virus vaccines. He led one of the largest studies evaluating the immune response to influenza vaccination in pregnant women. His work showed that the risk of flu halved in women given the flu vaccine. In addition, the risk to their newborns in the first 24 weeks of life was also reduced. The findings were presented at the 16th International Congress on Infectious Diseases and he reported that his "data support the recent WHO recommendation in terms of prioritizing pregnant women for influenza vaccination, not just for the protection of the mother, but protection of the infant as well". Later, he became involved in the clinical development of a vaccine against Group B streptococcus for pregnant women.
Tuberculosis
Other research has involved assessing the efficacy of various drug regimens to prevent tuberculosis (TB) in people with HIV.
COVID-19
Since the global COVID-19 pandemic in 2020, he has been leading COVID-19 vaccine trials in South Africa, including the Novavax COVID-19 vaccine and the Oxford-AstraZeneca vaccine, the first COVID-19 vaccine clinical trial in the continent of Africa. Asserting that South Africa's second wave in December 2020 is largely driven by mass gatherings and changing people's behaviour, rather than solely on the new variant, he has called for a wider coverage of COVID-19 vaccination. His co-authored publication on results of a large clinical trial of a COVID-19 vaccine suggest that the vaccine is safe and effective. In 2021 he made it clear that the first and foremost method of ending COVID-19 in South Africa is to implement a mass vaccination programme. On 1 January 2021 he tweeted "Ability of vaccines to impact on the pandemic is directly related to how soon you can get approx 50–60% of the population vaccinated."
Awards and honours
Since 2012, he has been considered an internationally recognised scientist with an A-rating by the South Africa's National Research Foundation. In 2014 he received the Platinum Medal, South African Medical Research Council's life-time award. In 2016 he received the European Developing Clinical Trial Partnership Scientific Award.
In 2023 he was made an Honorary Commander of the Order of the British Empire (CBE) from British Government for services to science and public health in a global pandemic.
Selected publications
Madhi has authored more than 350 publications between 1997 and 2018, covering topics such as childhood vaccines, pneumonia, severe infections in young children and vaccination in pregnancy.
Articles
(Lead author)
(Co-author)
(Co-author)
(Co-author)
References
External links
Publications on PubFacts
1966 births
Living people
Members of the Academy of Science of South Africa
Academic staff of the University of the Witwatersrand
University of the Witwatersrand alumni
Vaccinologists
Vaccination advocates
Honorary commanders of the Order of the British Empire
South African people of Indian descent | Shabir Madhi | Biology | 1,371 |
35,793,286 | https://en.wikipedia.org/wiki/Power%20diagram | In computational geometry, a power diagram, also called a Laguerre–Voronoi diagram, Dirichlet cell complex, radical Voronoi tesselation or a sectional Dirichlet tesselation, is a partition of the Euclidean plane into polygonal cells defined from a set of circles. The cell for a given circle C consists of all the points for which the power distance to C is smaller than the power distance to the other circles. The power diagram is a form of generalized Voronoi diagram, and coincides with the Voronoi diagram of the circle centers in the case that all the circles have equal radii.
Definition
If C is a circle and P is a point outside C, then the power of P with respect to C is the square of the length of a line segment from P to a point T of tangency with C. Equivalently, if P has distance d from the center of the circle, and the circle has radius r, then (by the Pythagorean theorem) the power is d2 − r2. The same formula d2 − r2 may be extended to all points in the plane, regardless of whether they are inside or outside of C: points on C have zero power, and points inside C have negative power.
The power diagram of a set of n circles Ci is a partition of the plane into n regions Ri (called cells), such that a point P belongs to Ri whenever circle Ci is the circle minimizing the power of P.
In the case n = 2, the power diagram consists of two halfplanes, separated by a line called the radical axis or chordale of the two circles. Along the radical axis, both circles have equal power. More generally, in any power diagram, each cell Ri is a convex polygon, the intersection of the halfspaces bounded by the radical axes of circle Ci with each other circle. Triples of cells meet at vertices of the diagram, which are the radical centers of the three circles whose cells meet at the vertex.
Related constructions
The power diagram may be seen as a weighted form of the Voronoi diagram of a set of point sites, a partition of the plane into cells within which one of the sites is closer than all the other sites. Other forms of weighted Voronoi diagram include the additively weighted Voronoi diagram, in which each site has a weight that is added to its distance before comparing it to the distances to the other sites, and the multiplicatively weighted Voronoi diagram, in which the weight of a site is multiplied by its distance before comparing it to the distances to the other sites. In contrast, in the power diagram, we may view each circle center as a site, and each circle's squared radius as a weight that is subtracted from the squared Euclidean distance before comparing it to other squared distances. In the case that all the circle radii are equal, this subtraction makes no difference to the comparison, and the power diagram coincides with the Voronoi diagram.
A planar power diagram may also be interpreted as a planar cross-section of an unweighted three-dimensional Voronoi diagram. In this interpretation, the set of circle centers in the cross-section plane are the perpendicular projections of the three-dimensional Voronoi sites, and the squared radius of each circle is a constant K minus the squared distance of the corresponding site from the cross-section plane, where K is chosen large enough to make all these radii positive.
Like the Voronoi diagram, the power diagram may be generalized to Euclidean spaces of any dimension. The power diagram of n spheres in d dimensions is combinatorially equivalent to the intersection of a set of n upward-facing halfspaces in d + 1 dimensions, and vice versa.
Algorithms and applications
Two-dimensional power diagrams may be constructed by an algorithm that runs in time O(n log n). More generally, because of the equivalence with higher-dimensional halfspace intersections, d-dimensional power diagrams (for d > 2) may be constructed by an algorithm that runs in time .
The power diagram may be used as part of an efficient algorithm for computing the volume of a union of spheres. Intersecting each sphere with its power diagram cell gives its contribution to the total union, from which the volume may be computed in time proportional to the complexity of the power diagram.
Other applications of power diagrams include data structures for testing whether a point belongs to a union of disks, algorithms for constructing the boundary of a union of disks, and algorithms for finding the closest two balls in a set of balls. It is also used for solving the semi-discrete optimal transportation problem which in turn has numerous applications, such as early universe reconstruction or fluid dynamics.
History
traces the definition of the power distance to the work of 19th-century mathematicians Edmond Laguerre and Georgy Voronoy. defined power diagrams and used them to show that the boundary of a union of n circular disks can always be illuminated from at most 2n point light sources. Power diagrams have appeared in the literature under other names including the "Laguerre–Voronoi diagram", "Dirichlet cell complex", "radical Voronoi tesselation" and "sectional Dirichlet tesselation".
References
Computational geometry
Diagrams | Power diagram | Mathematics | 1,085 |
67,103,631 | https://en.wikipedia.org/wiki/Kamal%20Benslama | Kamal Benslama is a Moroccan-Swiss experimental particle physicist. He is a professor of physics at Drew University, a visiting experimental scientist at Fermilab, and a guest scientist at Brookhaven National Laboratory. He worked on the ATLAS experiment, at the Large Hadron Collider (LHC) at CERN in Switzerland. Currently, he is a member of the Mu2e experiment at Fermilab.
Biography
Originally from Morocco, Benslama studied physics at Geneva University. He obtained a bachelor and a master's degree in high-energy physics from Geneva University. In 1998, he completed a PhD at the department of High Energy Physics at the University of Lausanne.
After a short post-doc at the University of Lausanne, Benslama moved to North America in 1999. He first worked as a post-doc on the CLEO experiment at Cornell University in the US, and while at Cornell he collaborated with Syracuse University and the University of Illinois Urbana-Champaign. Then he became a research associate at the University of Montreal before becoming a post-doctoral research scientist at Columbia University in New York and associate scientist on the ATLAS experiment at Large Hadron Collider (LHC) at CERN. from 2006 to 2012, he was a professor of physics at the University of Regina in Canada. During this time, Benslama founded and led an international research group in experimental high-energy physics. He worked on the ATLAS experiment at CERN where he was a principal investigator and a team leader. He also was a member of the international ATLAS collaboration board and a member of the Liquid Argon representative board.
Benslama started his research activities at CERN in 1992, he first worked on ATLAS, then on NOMAD, (Neutrino Oscillation search with a MAgnetic Detector) which was designed to search for neutrino oscillation. His thesis was on the construction, installation and simulation of a preshower particle detector as well as on data analysis using data from the NOMAD experiment.
Benslama contributed to many aspects of the ATLAS experiment. He worked on a readout system for a silicon detector for the ATLAS experiment, then he worked on the Liquid Argon Calorimeter, the High Level Trigger and Data Quality and Monitoring. He also led several efforts on searches for physics beyond the standard model at the LHC, in particular searches for doubly charged higgs, extra-dimensions and leptoquarks. He was heavily involved in the exotics physics program at the LHC.
Before joining Drew University as a faculty, Benslama was a visiting professor at Loyola University Maryland and later he was a Senior Lecturer and Research Professor at Towson University
Private life
Kamal Benslama has three children and lives in New Jersey.
Selected work
Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
Prospects for the search for a doubly charged Higgs in the left–right symmetric model with ATLAS - G. Azuelos, K. Benslama, J. Ferland, 10 March 2005, J.Phys.G32:73-92,2006
Exploring Little Higgs Models with ATLAS at the LHC - Azuelos, G; Benslama, K. Benslama et al. - Eur. Phys. J., C 39 (2005) 13-24
Design and implementation of the Front End Board for the readout of the ATLAS liquid argon calorimeters - N.~J.~Buchanan et al. - JINST 3, P03004 (2008)
Search for pair production of first or second generation leptoquarks in proton-proton collisions at √s=7 TeV using the ATLAS detector at the LHC
Measurement of the top quark-pair production cross section with ATLAS in pp collisions at sqrt(s)=7 TeV
Measurement of the W → ℓν and Z/γ* → ℓℓ production cross sections in proton-proton collisions at sqrt(s)=7TeV with the ATLAS detector
Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton–proton collision data
Measurements of charmless hadronic two-body B meson decays and the ratio B(B to DK)/B(B to DPi)
Liste de publications et citations
References
External links
FermiLab
The ATLAS Experiment
Large Hadron Collider at CERN
20th-century births
20th-century Swiss physicists
21st-century Swiss physicists
Moroccan physicists
Particle physicists
Living people
Experimental physicists
University of Lausanne alumni
Year of birth missing (living people)
University of Geneva alumni
People associated with CERN
Swiss people of Moroccan descent
Swiss expatriates in the United States
Cornell University staff
Columbia University staff
Academic staff of the University of Regina
Drew University faculty | Kamal Benslama | Physics | 989 |
3,578,707 | https://en.wikipedia.org/wiki/Compact%20disc%20manufacturing | Compact disc manufacturing is the process by which commercial compact discs (CDs) are replicated in mass quantities using a master version created from a source recording. This may be either in audio form (CD-DA) or data form (CD-ROM). This process is used in the mastering of read-only compact discs. DVDs and Blu-rays use similar methods (see ).
A CD can be used to store audio, video, and data in various standardized formats defined in the Rainbow Books. CDs are usually manufactured in a class 100 (ISO 5) or better clean room, to avoid contamination which would result in data corruption. They can be manufactured to strict manufacturing tolerances for only a few US cents per disk.
Replication differs from duplication (i.e. burning used for CD-Rs and CD-RWs) as the pits and lands of a replicated CD are moulded into a CD blank, rather than being burn marks in a dye layer (in CD-Rs) or areas with changed physical characteristics (in CD-RWs). In addition, CD burners write data sequentially, while a CD pressing plant forms the entire disk in one physical stamping operation, similar to record pressing.
Premastering
All CDs are pressed from a digital data source, with the most common sources being low error-rate CD-Rs or files from an attached computer hard drive containing the finished data (e. g., music or computer data). Some CD pressing systems can use digital master tapes, either in Digital Audio Tape, Exabyte, Digital Linear Tape, Digital Audio Stationary Head or Umatic formats. A PCM adaptor is used to record and retrieve digital audio data into and from an analog videocassette format such as Umatic or Betamax. However, such sources are suitable only for production of audio CDs due to error detection and correction issues. If the source is not a CD, the table of contents for the CD to be pressed must also be prepared and stored on a tape or hard drive. In all cases except CD-R sources, the tape must be uploaded to a media mastering system to create the TOC (Table Of Contents) for the CD. Creative processing of the mixed audio recordings often occurs in conventional CD premastering sessions. The term often used for this is "mastering," but the official name, as explained in Bob Katz book, Mastering Audio, edition 1, page 18, is 'premastering' because there still has to be the creation of another disc carrying the premastered audio which supplies the work surface on which the metal master (stamper) will be electroformed.
Mastering
Glass mastering
Glass mastering is performed in a class 100 (ISO 5) or better clean room or a self-enclosed clean environment within the mastering system. Contaminants introduced during critical stages of manufacturing (e.g., dust, pollen, hair, or smoke) can cause sufficient errors to make a master unusable. Once successfully completed, a CD master will be less susceptible to the effects of these contaminants.
During glass mastering, glass is used as a substrate to hold the CD master image while it is created and processed; hence the name. Glass substrates, noticeably larger than a CD, are round plates of glass approximately 240 mm in diameter and 6 mm thick. They often also have a small, steel hub on one side to facilitate handling. The substrates are created especially for CD mastering and one side is polished until it is extremely smooth. Even microscopic scratches in the glass will affect the quality of CDs pressed from the master image. The extra area on the substrate allows for easier handling of the glass master and reduces the risk of damage to the pit and land structure when the "father" stamper is removed from the glass substrate.
Once the glass substrate is cleaned using detergents and ultrasonic baths, the glass is placed in a spin coater. The spin coater rinses the glass blank with a solvent and then applies either photoresist or dye-polymer depending on the mastering process. Rotation spreads photoresist or dye-polymer coating evenly across the surface of the glass. The substrate is removed and baked to dry the coating and the glass substrate is ready for mastering.
Once the glass is ready for mastering, it is placed in a laser beam recorder (LBR). Most LBRs are capable of mastering at greater than 1x speed, but due to the weight of the glass substrate and the requirements of a CD master they are typically mastered at no greater than 8x playback speed. The LBR uses a laser to write the information, with a wavelength and final lens NA (numerical aperture) chosen to produce the required pit size on the master blank. For example, DVD pits are smaller than CD pits, so a shorter wavelength or higher NA (or both) is needed for DVD mastering. LBRs use one of two recording techniques; photoresist and non-photoresist mastering. Photoresist also comes in two variations; positive photoresist and negative photoresist.
Photoresist mastering
Photoresist mastering uses a light-sensitive material (a photoresist) to create the pits and lands on the CD master blank. The laser beam recorder uses a deep blue or ultraviolet laser to write the master. When exposed to the laser light, the photoresist undergoes a chemical reaction which either hardens it (in the case of negative photoresist) or to the contrary makes it more soluble (in the case of positive photoresist).
Once the mastering is complete, the glass master is removed from the LBR and chemically 'developed'. The exposed area is then soaked in a developer solution which removes the exposed positive photoresist or the unexposed negative photoresist. Once developing is finished, the glass master is metalized to provide a surface for the stamper to be formed onto.
It is then polished with lubricant and wiped down.
Non-photoresist or dye-polymer mastering
When a laser is used to record on the dye-polymer used in non-photoresist (NPR) mastering, the dye-polymer absorbs laser energy focused in a precise spot; this vapourises and forms a pit in the surface of the dye-polymer. This pit can be scanned by a red laser beam that follows the cutting beam, and the quality of the recording can be directly and immediately assessed; for instance, audio signals being recorded can also be played straight from the glass master in real time. The pit geometry and quality of the playback can all be adjusted while the CD is being mastered, as the blue writing laser and the red read laser are typically connected via a feedback system to optimise the recording. This allows the dye-polymer LBR to produce very consistent pits even if there are variations in the dye-polymer layer. Another advantage of this method is that pit depth variation can be programmed during recording to compensate for downstream characteristics of the local production process (e.g., marginal molding performance). This cannot be done with photoresist mastering because the pit depth is set by the PR coating thickness, whereas dye-polymer pits are cut into a coating thicker than the intended pits.
This type of mastering is called Direct Read After Write (DRAW) and is the main advantage of some non-photoresist recording systems. Problems with the quality of the glass blank master, such as scratches, or an uneven dye-polymer coating, can be immediately detected. If required, the mastering can be halted, saving time and increasing throughput.
Post-mastering
After mastering, the glass master is baked to harden the developed surface material to prepare it for metalisation. Metalisation is a critical step prior to electrogalvanic manufacture (electroplating).
The developed glass master is placed in a vapour deposition metallizer which uses a combination of mechanical vacuum pumps and cryopumps to lower the total vapour pressure inside a chamber to a hard vacuum. A piece of nickel wire is then heated in a tungsten boat to white-hot temperature and the nickel vapour deposited onto the rotating glass master. The glass master is coated with the nickel vapour up to a typical thickness of around 400 nm.
The finished glass masters are inspected for stains, pinholes or incomplete coverage of the nickel coating and passed to the next step in the mastering process.
Electroforming
Electroforming occurs in "Matrix", the name used for the electroforming process area in many plants; it is also a class 100 (ISO 5) or better clean room. The data (music, computer data, etc.) on the metalised glass master is extremely easy to damage and must be transferred to a tougher form for use in the injection moulding equipment which actually produces the end-product optical disks.
The metalised master is clamped in a conductive electrodeposition frame with the data side facing outwards and lowered into an electroforming tank. The specially prepared and controlled tank water contains a nickel salt solution (usually nickel sulfamate) at a particular concentration which may be adjusted slightly in different plants depending on the characteristics of the prior steps. The solution is carefully buffered to maintain its pH, and organic contaminants must be kept below one part in five million for good results. The bath is heated to approximately 50 °C.
The glass master is rotated in the electroforming tank while a pump circulates the electroforming solution over the surface of the master. As the electroforming progresses, nickel is not electroplated onto the surface of the glass master, since that would preclude separation. Plating is rather eschewed through passivation and, initially, because the glass is not electroconductive. Instead, the metal coating on the glass disc, actually reverse-plates onto the nickel (not the mandrel) which is being electrodeposited by the attraction of the electrons on the cathode, which presents itself as the metal-coated glass mistress, or, premaster mandrel. Electroplating, on the other hand, would have entailed electrodeposition directly to the mandrel along with the intention of it staying adhered. That, and the more rigorous requirements of temperature control and purity of bathwater, are the main differences between the two disciplines of electrodeposition. The metal stamper first struck from the metal-coated glass is the metal master (and we shouldn't make a master from another master as that would not follow the nomenclature of the sequence of siring that is germane to electroforming) This is clearly a method opposite to normal electroplating. Another difference to electroplating is that the internal stress of the nickel must be controlled carefully, or the nickel stamper will not be flat. The solution cleanliness is important but is achieved by continuous filtration and usual anode bagging systems. Another large difference is that the stamper thickness must be controlled to ±2% of the final thickness so that it will fit on the injection moulding machines with very high tolerances of gassing rings and centre clamps. This thickness control requires electronic current control and baffles in the solution to control distribution. The current must start off quite low as the metallised layer is too thin to take large currents, and is increased steadily. As the thickness of the nickel on the glass "mistress" increases, the current can be increased. The full electroforming current density is very high with the full thickness of usually 0.3 mm taking approximately one hour. The part is removed from the tank and the metal layer carefully separated from the glass substrate. If plating occurs, the process must be begun anew, from the glass mastering phase. The metal part, now called a "father", has the desired data as a series of bumps rather than pits. The injection moulding process works better by flowing around high points rather than into pits on the metal surface. The father is washed with deionised water and other chemicals such as ammonical hydrogen peroxide, sodium hydroxide or acetone to remove all trace of resist or other contaminants. The glass master can be sent for reclamation, cleaning and checking before reuse. If defects are detected, it will be discarded or repolished recycled.
Once cleaned of any loose nickel and resist, the father surface is washed and the passivated, either electrically or chemically, which allows the next plated layer to separate from the father. This layer is an atomic layer of absorbed oxygen that does not alter the physical surface. The father is clamped back into a frame and returned to the plating tank. This time the metal part that is grown is the mirror image of the father and is called a "mother"; as this is now pits, it cannot be used for moulding.
The mother-father sandwich is carefully separated and the mother is then washed, passivated and returned to the electroforming baths to have a mirror image produced on it called a son. Most moulded CDs are produced from sons.
Mothers can be regrown from fathers if they become damaged, or a very long run. If handled correctly, there is no limit to the number of stampers that can be grown from a single mother before the quality of the stamper is reduced unacceptably. Fathers can be used as a stamper, directly, if a very fast turnaround is required, or if the yield is 100%, in which case the father would be wastefully stored. At the end of a run, the mother is certainly to be stored.
A father, mother, and a collection of stampers (sometimes called "sons") are known collectively as a "family". Fathers and mothers are the same size as a glass substrate, typically 300 μm in thickness. Stampers do not require the extra space around the outside of the program area and they are punched to remove the excess nickel from outside and inside the information area in order to fit the mould of the injection moulding machine (IMM). The physical dimensions of the mould vary depending on the injection tooling being used.
Replication
CD moulding machines are specifically designed high temperature polycarbonate injection moulders. They have an average throughput of 550-900 discs per hour, per moulding line. Clear polycarbonate pellets are first dried at around 130 degrees Celsius for three hours (nominal; this depends on which optical grade resin is in use) and are fed via vacuum transport into one end of the injection moulder's barrel (i.e., the feed throat) and are moved to the injection chamber via a large screw inside the barrel. The barrel, wrapped with heater bands ranging in temperature from ca 210 to 320 degrees Celsius melts the polycarbonate. When the mould is closed the screw moves forward to inject molten plastic into the mould cavity. When the mould is full, cool water running through mould halves, outside the cavity, cools the plastic so it somewhat solidifies. The entire process from the mould closing, injection and opening again takes approximately 3 to 5 seconds.
The moulded "disc" (referred to as a 'green' disc, lacking final processing) is removed from the mould by vacuum handling; high-speed robot arms with vacuum suction caps. They are moved onto the finishing line infeed conveyor, or cooling station, in preparation for metallisation. At this point the discs are clear and contain all the digital information desired; however, they cannot be played because there is no reflective layer.
The discs pass, one at a time, into the metallizer, a small chamber at approximately 10−3 Torr (130 mPa) vacuum. The process is called 'sputtering'. The metallizer contains a metal "target" – almost always an alloy of (mostly) aluminium and small amounts of other metals. There is a load-lock system (similar to an airlock) so the process chamber can be kept at high vacuum as the discs are exchanged. When the disc is rotated into the processing position by a swivel arm in the vacuum chamber, a small dose of argon gas is injected into the process chamber and a 700 volt DC electric current at up to 20 kW is applied to the target. This produces a plasma from the target, and the plasma vapour is deposited onto the disc; it is an anode-cathode transfer. The metal coats the data side of the disc (upper surface), covering the pit and lands. This metal layer is the reflective surface which can be seen on the reverse (non-label side) of a CD. This thin layer of metal is subject to corrosion from various contaminants and so is protected by a thin layer of lacquer.
After metalisation, the discs pass on to a spin-coater, where UV curable lacquer is dispensed onto the newly metallized layer. By rapid spinning, the lacquer coats the entire disc with a very thin layer (approximately 5 to 10 μm). After the lacquer is applied, the discs pass under a high-intensity UV lamp which cures the lacquer rapidly. The lacquer also provides a surface for a label, generally screen printed or offset printed. The printing ink(s) must be chemically compatible with the lacquer used. Markers used by consumers to write on blank surfaces can lead to breaks in the protective lacquer layer, which may lead to corrosion of the reflective layer, and failure of the CD.
Testing
For quality control, both the stamper and the moulded discs are tested before a production run. Samples of the disc (test pressings) are taken during long production runs and tested for quality consistency. Pressed discs are analyzed on a signal analysis machine. The metal stamper can also be tested on a signal analysis machine which has been specially adapted (larger diameter, more fragile, ...).
The machine will scan the disc or stamper and measure various physical and electrical parameters. Errors can be introduced at every step of production, but the moulding process is the least subject to adjustment. Sources of errors are more readily identified and compensated for during mastering. If the errors are too severe then the stamper is rejected and a replacement installed. An experienced machine operator can interpret the report from the analysis system and optimise the moulding process to make a disc that meets the required Rainbow Book specification (e.g. Red Book for Audio from the Rainbow Books series).
If no defects are found, the CD continues to printing so a label can be screen or offset printed on the top surface of the disc. Thereafter, discs are counted, packaged, and shipped.
Manufacturers
Cinram (former)
Moser Baer
Ritek
Sony DADC
See also
CD publishing
Optical disc authoring
References
External links
How compact discs are made -- Explained by a layman for the laymen
Introduction to CD Duplication
Manufacturing
Optical disc authoring | Compact disc manufacturing | Technology | 3,897 |
1,709,404 | https://en.wikipedia.org/wiki/Media%20resource%20locator | A media resource locator (MRL) is a URI used to uniquely identify and locate a multimedia resource. It is used by the VideoLAN and Xine media players, as well as the Java Media Framework (JMF) API.
VLC, for example, supports the following MRLs:
dvd://[][@][@[][,[][,]]]
vcd://[][@{E|P|E|T|S}[]]
http://[:]/[]
rtsp://[:]/
Several media players also support Video4Linux as v4l:// and v4l2://.
References
Media players | Media resource locator | Technology | 157 |
3,038,539 | https://en.wikipedia.org/wiki/Composite%20gravity | In theoretical physics, composite gravity refers to models that attempted to derive general relativity in a framework where the graviton is constructed as a composite bound state of more elementary particles, usually fermions. A theorem by Steven Weinberg and Edward Witten shows that this is not possible in Lorentz covariant theories: massless particles with spin greater than one are forbidden. The AdS/CFT correspondence may be viewed as a loophole in their argument. However, in this case not only the graviton is emergent; a whole spacetime dimension is emergent, too.
See also
Weinberg–Witten theorem
References
Theories of gravity
Quantum gravity
Emergence | Composite gravity | Physics | 136 |
24,093,087 | https://en.wikipedia.org/wiki/C16H12O6 | {{DISPLAYTITLE:C16H12O6}}
The molecular formula C16H12O6 (molar mass : 300.26 g/mol, exact mass : 300.063388) may refer to:
Chrysoeriol, a flavone
Diosmetin, a flavone
Evariquinone, an anthraquinone
Fallacinol, an anthraquinone
Hematein, an oxidized derivative of haematoxylin used in staining
Hispidulin, a flavone
Kalafungin, an antibiotic
Kaempferide, a flavonol
Leptosidin, an aurone
Pratensein, an isoflavone
Psi-tectorigenin, an isoflavone
Tectorigenin, an isoflavone
Teloschistin, an anthraquinone | C16H12O6 | Chemistry | 188 |
9,783,930 | https://en.wikipedia.org/wiki/UHF%20Follow-On%20satellite | Ultra High Frequency Follow-On (UFO) satellite system is a United States Department of Defense (DoD) program sponsored and operated by the United States Space Force to provide communications for airborne, ship, submarine and ground forces. The UFO constellation replaced the U.S. DoD Fleet Satellite Communications System (FLTSATCOM) constellation and consisted of eleven satellites. The ground terminal segment consists of equipment and resident personnel at existing satellite communication stations. The satellites are controlled by the 10th Space Operations Squadron (Space Delta 8) located at the Naval Base Ventura County, Point Mugu, California.
Satellite description
The Ultra high frequency (UHF) satellites primarily served tactical users. UFO provided almost twice as many channels as FLTSATCOM and has about 10% more power per channel. The Extremely high frequency (EHF) package on satellites four through eleven have an Earth coverage beam and a steerable five-degree spot beam that enhances its tactical use. The EHF capability also allows the UFO network to connect to the strategic Milstar system. Satellites eight, nine and ten also carry the Global Broadcast Service antennas that operate in the Ka-band. The Atlas was the launch vehicle of choice; however, space shuttle compatibility existed. The UFO bus and payload weigh . The solar panels spans and produces 2,500 watts at the end of the planned 14-year lifetime. The UHF system supports stationary and mobile users including manportable, ships, submarines, aircraft and other mobile terminals. The UFO Follow-On system is scheduled for replacement by the Mobile User Objective System (MUOS).
Block Upgrades
Block 1 satellites had UFH and SHF communications. Block 2 satellites, starting with UHF 4, added extremely high frequency package with 11 channels. Block 3 satellites replaced the SFH communications with Ka-band transponders. Block 4 satellite incorporated a digital UHF receiver and two additional UHF channels.
Launch
First launch of the UFO took place on 25 March 1993, with constellation completion dependent on replacement needs for the aging FLTSATCOM constellation.
Table of Satellites
References
External links
Boeing: UFO System
GlobalSecurity.org: UFO System
GlobalSecurity.org: MUOS system
Military communications
Equipment of the United States Space Force
Military space program of the United States
Satellites using the BSS-601 bus | UHF Follow-On satellite | Engineering | 462 |
44,111,579 | https://en.wikipedia.org/wiki/Carbon%20nanothread | A carbon nanothread (also called diamond nanothread) is a sp3-bonded, one-dimensional carbon crystalline nanomaterial. The tetrahedral sp3-bonding of its carbon is similar to that of diamond. Nanothreads are only a few atoms across, more than 300,000 times thinner than a human hair. They consist of a stiff, strong carbon core surrounded by hydrogen atoms. Carbon nanotubes, although also one-dimensional nanomaterials, in contrast have sp2-carbon bonding as is found in graphite. The smallest carbon nanothread has a diameter of only 0.2 nanometers, much smaller than the diameter of a single-wall carbon nanotube.
Synthesis
Nanothreads are synthesized by compressing liquid benzene to an extreme pressure of 20 GPa (around 200,000 times the air pressure at the surface of the Earth), and then slowly relieving that pressure. The mechanochemical synthesis reaction can be considered a form of organic solid state chemistry. The benzene chains form extremely thin, tight rings of carbon that are structurally similar to diamonds. Researchers at Cornell University have traced pathways from benzene to nanothreads, which may involve a series of organic [4+2] cycloaddition reactions along stacks of benzene molecules, followed by further reactions of unsaturated bonds. Recently synthesis of macroscopic single crystal arrays of nanothreads hundreds of microns in size has been reported. The order and lack of grain boundaries in single crystals is often very desirable because it facilitates both applications and characterization. In contrast, carbon nanotubes form only thin crystalline ropes. Control of the rate of compression and/or decompression appears to be important to the synthesis of polycrystalline and single crystal nanothreads. Slow compression/decompression may favor low energy reaction pathways. If the synthesis pressure for nanothreads can be reduced to 5 to 6 GPa, which is the pressure used for synthesis of industrial diamond, production on a large scale of >106 kg/yr would be possible. Recent advance on using strained cage-like molecules such as cubane as a precursor has successfully brought down the synthesis pressure to 12 GPa. Expanding the precursor library to non-aromatic, strained molecules offers new avenues to explore scalable production of carbon nanothreads.
The formation of nanothread crystals appears to be guided by uniaxial stress (mechanical stress in a particular single direction), to which the nanothreads consistently align. Reaction to form the crystals is not topochemical, as it involves a major rearrangement from a lower symmetry monoclinic benzene crystal to a higher symmetry hexagonal nanothread crystal. Topochemical reactions generally require commensuration between the periodicities and interatomic distances between reactant and product. The distances between benzene molecules with van der Waals separations between them must shrink by 40% or more as the short, strong covalent carbon-carbon bonds between them form during the nanothread synthesis reaction. Such large changes in geometry usual break up crystal order, but the nanothread reaction instead creates it. Even polycrystalline benzene reacts to form macroscopic single crystal packings of nanothreads hundreds of microns across. Topochemical solid state reactions such as the formation of single crystal polydiacetylenes from diacetylenes usually require a single crystal reactant to form a single crystal product.
The impetus for the formation of a hexagonal crystal appears to be the packing of circular cross section threads. The details of how it is possible to transform from a monoclinic benzene crystal to a hexagonal nanothread crystal are not yet fully understood. Further development of the theory of the effect of pressure on reactions may help.
Organic synthesis efforts towards polytwistane nanothreads have been reported.
History
In popular culture, diamond threads were first described by Arthur C. Clarke in his sci-fi novel The Fountains of Paradise set in the 22nd century, written in 1979.
Nanothreads were first investigated theoretically in 2001 by researchers at Penn State University and later by researchers at Cornell University. In 2014, researchers at Penn State University created the first sp3-carbon nanothreads in collaboration with Oak Ridge National Laboratory and the Carnegie Institution for Science. Prior to 2014, and despite a century of investigation, benzene was thought to produce only hydrogenated amorphous carbon when compressed. As of 2015, threads at least 90 nanometers in length had been created (compared to .5 meters for CNTs).
Structure
Since “diamond nanothreads” are sp3-bonded and one-dimensional they are unique in the matrix of hybridization (sp2/sp3) and dimensionality (0D/1D/2D/3D) for carbon nanomaterials.
Assuming a topological unit cell of one or two benzene rings with at least two bonds interconnecting each adjacent pair of rings, 50 topologically distinct nanothreads have been enumerated. 15 of these are within 80 meV/carbon atom of the most stable member. Some of the more commonly discussed nanothread structures are known informally as polytwistane, tube (3,0), and Polymer I. Polytwistane is chiral. Tube (3,0) can be thought of as the thinnest possible thread that can be carved out of the diamond structure, consisting of stacked cyclohexane rings. Polymer I was predicted to form from benzene at high pressure.
Although there is compelling evidence from two dimensional X-ray diffraction patterns, transmission electron diffraction, and solid-state nuclear magnetic resonance (NMR) for a structure consisting of hexagonally packed crystals of 6.5 Angstrom diameter nanothreads with largely (75 to 80%) sp3-bonding, the atomic structure of nanothreads is still under investigation. Nanothreads have also been observed by transmission electron microscopy. Individual threads have been observed to pack in hexagonal crystals and layer-lines indicative of order along their length have been observed.
Nanothreads have also been classified by their degree of saturation. Fully saturated degree 6 nanothreads have no double bonds remaining. Three bonds form between each pair of benzene molecules. Degree 4 nanothreads have a double bond remaining from benzene and thus only two bonds formed between each pair of benzene molecules. Degree 2 have two double bonds remaining. Unless otherwise specified the term nanothread is assumed to refer to a degree six structure.
NMR has revealed that nanothread crystals consist of both degree 6 and degree 4 threads. Moreover, spin diffusion experiments show that the sections of the threads that are fully saturated degree 6 must be at least 2.5 nm long, if not longer. NMR also shows that no second hydrocarbon or carbon phase is present in nanothread crystals. Thus all of the sp2 carbon is either in degree 4 nanothreads or small amounts of aromatic linker molecules, or even smaller amounts of C=O groups. NMR provides the chemical structural information necessary to refine syntheses towards pure degree 6 nanothreads, which are stronger than the partially saturated ones.
Carbon nitride nanothreads
Pyridine compressed slowly under pressure forms carbon nitride C5H5N nanothread crystals. They exhibit the six-fold diffraction "signature" of nanothread formation. NMR, chemical analysis and infrared spectroscopy provide further evidence for the synthesis of nanothreads from pyridine. Pyridine nanothreads incorporate significant amounts of nitrogen directly into their backbone. In contrast sp2 carbon nanotubes can only be doped with a small amount of nitrogen. A wide range of other functionalized nanothreads may be possible, as well as nanothreads from polycyclic aromatic hydrocarbon molecules.
Smallest nanothreads
Extending the ability to design and create nanothread architecture from a non-aromatic, saturated molecule has been a recent interest in order to achieve an entirely sp3-bonded nanothread structure. Hypothetical nanothread architectures built from the smallest diamondoids (adamantane) have been proposed to have higher mechanical strength than benzene nanothreads. The first experimental synthesis of a novel purely sp3 bonded one-dimensional carbon nanomaterial is realized via an endogenous solid-state polymerization of cubane. Pre-arranged cubane monomers in the bulk crystal undergo diradical polymerization guided by applied uniaxial stress, similar to benzene, produce a single-crystalline carbon nanomaterial. The cubane-derived nanothread exhibits a linear diamond structure with subnanometre-diameter of 0.2 nm, which is considered as the smallest member in the carbon nanothread family; thus, they promise to form the stiffest one-dimensional system known.
Properties
Every type of nanothread has a very high Young's modulus (stiffness). The value for the strongest type of nanothread is around 900 GPa compared to steel at 200 GPa and diamond at over 1,200 GPa. The strength of carbon nanothreads may rival or exceed that of carbon nanotubes (CNTs). Molecular dynamics and Density functional theory simulations have indicated a stiffness on the order of carbon nanotubes (approx. 850 GPa) and a specific strength of approx. 4 × 107 N·m/kg.
Much as graphite exfoliates into sheets and ultimately graphene, nanothread crystals exfoliate into fibers, consistent with their structure consisting of stiff, straight threads with a persistence length of ~100 nm that are held together with van der Waals forces. These fibers exhibit birefringence, as would be expected from their low dimensional character. In contrast, most polymers are much more flexible and often fold into crystalline lamella (see Crystallization of polymers) rather than forming into crystals that readily exfoliate.
Modeling suggests certain nanothreads may be auxetic, with a negative Poisson ratio. The thermal conductivity of nanothreads has been modeled. Modeling indicates their Bandgaps are tunable with strain over a wide range. The electrical conductivity of fully saturated nanothreads, driven by topology, may be much higher than expected.
Potential applications
Nanothreads can be thought of essentially as "flexible diamond". The extremely high specific strength predicted for them by modeling has attracted attention for applications such as space elevators and would be useful in other applications related to transportation, aerospace, and sports equipment. They may uniquely combine extreme strength, flexibility, and resilience. Chemically substituted nanothreads may facilitate load transfer between neighbors through covalent bonding to transfer their mechanical strength to a surrounding matrix. Modeling also suggests that the kinks associated with Stone-Wales transformations in nanothreads may facilitate interfacial load transfer to a surrounding matrix, making them useful for high strength composites. In contrast to carbon nanotubes, bonds to the exterior of nanothreads need not disrupt their carbon core because only three of the four tetrahedral bonds are needed form it. The “extra” bond usually formed to hydrogen could be instead be linked to another nanothread or another molecule or atom. Nanothreads may thus be thought of as "hybrids" that are both hydrocarbon molecules and carbon nanomaterials. Bonds to carbon nanotubes require their carbon to change from near planar sp2-bonding to tetrahedral sp3-bonding, thus disrupting their tubular geometry and possibly weakening them. Nanothreads may be less susceptible to loss of strength through defects than carbon nanotubes. Thus far the extreme strength predicted for carbon nanotubes has largely not been realized in practical applications because of issues with load transfer to the surroundings and defects at various length scales from that of atoms on up.
Exfoliation into individual nanothreads may be possible, facilitating further functionalization and assembly into functional materials. Theory indicates that "caged saturated hydrocarbons offering multiple σ-conductance channels (such as nanothreads) afford transmission far beyond what could be expected based upon conventional superposition laws, particularly if these pathways are composed entirely from quaternary carbon atoms."
The carbon core of nanothreads is very stiff relative to the backbone of conventional polymers. They should thus be able to precisely orient molecular functions attached along their length (by substitution of hydrogen) relative to each other and to heteroatoms or unsaturated bonds in their backbone. These features may enable biological applications, for example. Defects, functional groups, and/or heteroatoms incorporated either into or exterior to the backbone of nanothreads with controlled orientation and distance between them may allow for robust, well controlled fluorescence. Doping and incorporation of heteroatoms such as nitrogen or boron into the nanothread backbone may allow for enhanced conducting or semiconducting properties of nanothreads that allow for application as photocatalysts, electron emitters, or possibly superconductors.
Modeling suggests carbon nanothread resonators exhibit low dissipation and may be useful as chemical sensors that can detect very small mass changes.
Energy storage
Simulations show some achiral nanothread bundles may have specific energy density (when twisted) higher than lithium batteries.
See also
Carbon nanotube
Boron nitride nanotube
Buckypaper
Carbide-derived carbon
Carbon nanocone
Carbon nanofibers
Carbon nanoparticles
Carbon nanoscrolls
Carbon nanotube chemistry
Colossal carbon tube
Filamentous carbon
Graphene oxide paper
List of software for nanostructures modeling
Molecular modelling
Nanoflower
Diamondoid
Graphene
Graphane
Ninithi (nanotube modelling software)
Organic semiconductor
Selective chemistry of single-walled nanotubes
Silicon nanotubes
Timeline of carbon nanotubes
Vantablack, a substance produced in 2014; the blackest substance known
External links
Forget Graphene and Carbon Nanotubes, Get Ready for Diamond Nanothread technologyreview.com
Synthesizing Carbon Nanothreads from Benzene spie.org
Liquid Benzene Squeezed to Form Diamond Nanothreads Scientific American
Carbon Nanothread Bibliography
Center for Nanothread Chemistry
References
Carbon nanoparticles
Transparent electrodes
Refractory materials
Substances discovered in the 2000s | Carbon nanothread | Physics | 3,022 |
29,054,097 | https://en.wikipedia.org/wiki/National%20Survey%20of%20Sexual%20Health%20and%20Behavior | The National Survey of Sexual Health and Behavior is a decade-long nationally representative study of human sexual behavior. The research has been conducted in the United States by researchers from the Center for Sexual Health Promotion in the School of Public Health at Indiana University in Bloomington. Time magazine called the NSSHB "the most comprehensive survey of its kind in nearly two decades and the first to include teenagers." Former U.S. Surgeon General Dr. Joycelyn Elders has written the following about NSSHB findings: "These data are important for keeping the nation moving forward in the area of sexual health and well being. In the absence of scientific data available to construct an accurate and up-to-date view, opinions in the field of sexual science can vary widely from person to person."
There have been a total of seven waves of the NSSHB, all conducted between 2009 and 2018. More than 30 scientific articles have been published from these data. Articles based on the first wave of the study, the 2009 NSSHB, were initially released in a supplement to the October 2010 issue of Journal of Sexual Medicine. Since the NSSHB's inception in 2009, there have been a total of six additional waves of data collection. The NSSHB was the first U.S. nationally representative probability survey of sexual behavior in the United States conducted since the 1992 National Health and Social Life Survey. In Fall 2018, the researchers were honored with Indiana University's Outstanding Faculty Collaborative Research Award Lecture.
The 2009 NSSHB surveyed nearly 6,000 individuals between the age of 14 and 94, living in the United States. Findings showed a wide variety of sexual behavior. According to one of the lead investigators, Debby Herbenick, PhD, of Indiana University in Bloomington, "Adult men and women rarely engage in just one sex act when they have sex." In addition to Dr. Herbenick, the original core NSSHB team included Drs. Michael Reece, J. Dennis Fortenberry, Brian Dodge, Stephanie Sanders, and Vanessa Schick. Significant findings include use of condoms in about 25% of instances of vaginal sex by adults, about 33% if they were single, with teenagers using condoms 70 to 80% of the time. Only a low level of sexual activity among the approximately 800 teenagers surveyed was found with incidence increasing with age. It was discovered that about one third of women reported pain during intercourse. A discrepancy was discovered between men's perception that their female partner had experienced orgasm, about 85%, and women's self-reporting of 64%.
The NSSHB has been supported by funding from Church and Dwight, maker of Trojan condoms. The sponsor offered limited input on the survey development, mostly with respect to gathering information on how often Americans use condoms, settling with a formulation which requested information on whether condoms were used or not during the last 10 sexual encounters of each respondent.
With respect to condom use results were encouraging especially with respect to teenagers. Ethnic populations impacted by HIV/AIDS showed a higher rate of condom use than then general population as did dating adults. Discrepancies remain between the level of condom use considered optimal for public health and reported rate of use particularly by people over 40.
Women reported less satisfaction with sexual activity than men with less pleasure, less arousal, and fewer orgasms. This was hypothesized by one of the researchers as being related to the greater incidence of pain also reported by women.
In the 2012 NSSHB, researchers found that pain during vaginal intercourse was reported by 30% of women and 7% of men. Additionally, pain during anal intercourse was reported by 72% of women and 15% of men.
In a publication from the 2016, the researchers found that although most sexually active adults between ages 18 and 50 were aware that Zika could be transmitted by mosquitos, only about 40% identified sexual intercourse as a possible route of transmission.
In a 2018 NSSHB publication, it was found that about 60% of Americans who reported on a recent sexual event reported having ejaculated somewhere outside of the vagina at least once. Looking at the most recent sexual event, findings showed a lack of concordance between the percentage of people indicating they used "withdrawal" at their most recent sexual event compared with where they said they ejaculated.
Notes
External links
Center for Sexual Health Promotion
National Survey of Sexual Health and Behavior Website (includes free download of the special issue of The Journal of Sexual Medicine)
The Journal of Sexual Medicine
"Condom Use Is Highest for Young, Study Finds" article by Roni Caryn Rabin in The New York Times October 4, 2010
"Sex in America" season 2, episode 4 of "Curiosity" on Discovery which documentary presents the results of this study.
Human sexuality
Intimate relationships
Surveys (human research) | National Survey of Sexual Health and Behavior | Biology | 979 |
3,406,245 | https://en.wikipedia.org/wiki/Routhian%20mechanics | In classical mechanics, Routh's procedure or Routhian mechanics is a hybrid formulation of Lagrangian mechanics and Hamiltonian mechanics developed by Edward John Routh. Correspondingly, the Routhian is the function which replaces both the Lagrangian and Hamiltonian functions. Although Routhian mechanics is equivalent to Lagrangian mechanics and Hamiltonian mechanics, and introduces no new physics, it offers an alternative way to solve mechanical problems.
Definitions
The Routhian, like the Hamiltonian, can be obtained from a Legendre transform of the Lagrangian, and has a similar mathematical form to the Hamiltonian, but is not exactly the same. The difference between the Lagrangian, Hamiltonian, and Routhian functions are their variables. For a given set of generalized coordinates representing the degrees of freedom in the system, the Lagrangian is a function of the coordinates and velocities, while the Hamiltonian is a function of the coordinates and momenta.
The Routhian differs from these functions in that some coordinates are chosen to have corresponding generalized velocities, the rest to have corresponding generalized momenta. This choice is arbitrary, and can be done to simplify the problem. It also has the consequence that the Routhian equations are exactly the Hamiltonian equations for some coordinates and corresponding momenta, and the Lagrangian equations for the rest of the coordinates and their velocities. In each case the Lagrangian and Hamiltonian functions are replaced by a single function, the Routhian. The full set thus has the advantages of both sets of equations, with the convenience of splitting one set of coordinates to the Hamilton equations, and the rest to the Lagrangian equations.
In the case of Lagrangian mechanics, the generalized coordinates , ... and the corresponding velocities , and possibly time , enter the Lagrangian,
where the overdots denote time derivatives.
In Hamiltonian mechanics, the generalized coordinates and the corresponding generalized momenta and possibly time, enter the Hamiltonian,
where the second equation is the definition of the generalized momentum corresponding to the coordinate (partial derivatives are denoted using ). The velocities are expressed as functions of their corresponding momenta by inverting their defining relation. In this context, is said to be the momentum "canonically conjugate" to .
The Routhian is intermediate between and ; some coordinates are chosen to have corresponding generalized momenta , the rest of the coordinates to have generalized velocities , and time may appear explicitly;
where again the generalized velocity is to be expressed as a function of generalized momentum via its defining relation. The choice of which coordinates are to have corresponding momenta, out of the coordinates, is arbitrary.
The above is used by Landau and Lifshitz, and Goldstein. Some authors may define the Routhian to be the negative of the above definition.
Given the length of the general definition, a more compact notation is to use boldface for tuples (or vectors) of the variables, thus , , , and , so that
where · is the dot product defined on the tuples, for the specific example appearing here:
Equations of motion
For reference, the Euler-Lagrange equations for degrees of freedom are a set of coupled second order ordinary differential equations in the coordinates
where , and the Hamiltonian equations for degrees of freedom are a set of coupled first order ordinary differential equations in the coordinates and momenta
Below, the Routhian equations of motion are obtained in two ways, in the process other useful derivatives are found that can be used elsewhere.
Two degrees of freedom
Consider the case of a system with two degrees of freedom, and , with generalized velocities and , and the Lagrangian is time-dependent. (The generalization to any number of degrees of freedom follows exactly the same procedure as with two). The Lagrangian of the system will have the form
The differential of is
Now change variables, from the set (, , , ) to (, , , ), simply switching the velocity to the momentum . This change of variables in the differentials is the Legendre transformation. The differential of the new function to replace will be a sum of differentials in , , , , and . Using the definition of generalized momentum and Lagrange's equation for the coordinate :
we have
and to replace by , recall the product rule for differentials, and substitute
to obtain the differential of a new function in terms of the new set of variables:
Introducing the Routhian
where again the velocity is a function of the momentum , we have
but from the above definition, the differential of the Routhian is
Comparing the coefficients of the differentials , , , , and , the results are Hamilton's equations for the coordinate ,
and Lagrange's equation for the coordinate
which follow from
and taking the total time derivative of the second equation and equating to the first. Notice the Routhian replaces the Hamiltonian and Lagrangian functions in all the equations of motion.
The remaining equation states the partial time derivatives of and are negatives
Any number of degrees of freedom
For coordinates as defined above, with Routhian
the equations of motion can be derived by a Legendre transformation of this Routhian as in the previous section, but another way is to simply take the partial derivatives of with respect to the coordinates and , momenta , and velocities , where , and . The derivatives are
The first two are identically the Hamiltonian equations. Equating the total time derivative of the fourth set of equations with the third (for each value of ) gives the Lagrangian equations. The fifth is just the same relation between time partial derivatives as before. To summarize
The total number of equations is , there are Hamiltonian equations plus Lagrange equations.
Energy
Since the Lagrangian has the same units as energy, the units of the Routhian are also energy. In SI units this is the Joule.
Taking the total time derivative of the Lagrangian leads to the general result
If the Lagrangian is independent of time, the partial time derivative of the Lagrangian is zero, , so the quantity under the total time derivative in brackets must be a constant, it is the total energy of the system
(If there are external fields interacting with the constituents of the system, they can vary throughout space but not time). This expression requires the partial derivatives of with respect to all the velocities and . Under the same condition of being time independent, the energy in terms of the Routhian is a little simpler, substituting the definition of and the partial derivatives of with respect to the velocities ,
Notice only the partial derivatives of with respect to the velocities are needed. In the case that and the Routhian is explicitly time-independent, then , that is, the Routhian equals the energy of the system. The same expression for in when is also the Hamiltonian, so in all .
If the Routhian has explicit time dependence, the total energy of the system is not constant. The general result is
which can be derived from the total time derivative of in the same way as for .
Cyclic coordinates
Often the Routhian approach may offer no advantage, but one notable case where this is useful is when a system has cyclic coordinates (also called "ignorable coordinates"), by definition those coordinates which do not appear in the original Lagrangian. The Lagrangian equations are powerful results, used frequently in theory and practice, since the equations of motion in the coordinates are easy to set up. However, if cyclic coordinates occur there will still be equations to solve for all the coordinates, including the cyclic coordinates despite their absence in the Lagrangian. The Hamiltonian equations are useful theoretical results, but less useful in practice because coordinates and momenta are related together in the solutions - after solving the equations the coordinates and momenta must be eliminated from each other. Nevertheless, the Hamiltonian equations are perfectly suited to cyclic coordinates because the equations in the cyclic coordinates trivially vanish, leaving only the equations in the non cyclic coordinates.
The Routhian approach has the best of both approaches, because cyclic coordinates can be split off to the Hamiltonian equations and eliminated, leaving behind the non cyclic coordinates to be solved from the Lagrangian equations. Overall fewer equations need to be solved compared to the Lagrangian approach.
The Routhian formulation is useful for systems with cyclic coordinates, because by definition those coordinates do not enter , and hence . The corresponding partial derivatives of and with respect to those coordinates are zero, which equates to the corresponding generalized momenta reducing to constants. To make this concrete, if the are all cyclic coordinates, and the are all non cyclic, then
where the are constants. With these constants substituted into the Routhian, is a function of only the non cyclic coordinates and velocities (and in general time also)
The Hamiltonian equation in the cyclic coordinates automatically vanishes,
and the Lagrangian equations are in the non cyclic coordinates
Thus the problem has been reduced to solving the Lagrangian equations in the non cyclic coordinates, with the advantage of the Hamiltonian equations cleanly removing the cyclic coordinates. Using those solutions, the equations for can be integrated to compute .
If we are interested in how the cyclic coordinates change with time, the equations for the generalized velocities corresponding to the cyclic coordinates can be integrated.
Examples
Routh's procedure does not guarantee the equations of motion will be simple, however it will lead to fewer equations.
Central potential in spherical coordinates
One general class of mechanical systems with cyclic coordinates are those with central potentials, because potentials of this form only have dependence on radial separations and no dependence on angles.
Consider a particle of mass under the influence of a central potential in spherical polar coordinates
Notice is cyclic, because it does not appear in the Lagrangian. The momentum conjugate to is the constant
in which and can vary with time, but the angular momentum is constant. The Routhian can be taken to be
We can solve for and using Lagrange's equations, and do not need to solve for since it is eliminated by Hamiltonian's equations. The equation is
and the equation is
The Routhian approach has obtained two coupled nonlinear equations. By contrast the Lagrangian approach leads to three nonlinear coupled equations, mixing in the first and second time derivatives of in all of them, despite its absence from the Lagrangian.
The equation is
the equation is
the equation is
Symmetric mechanical systems
Spherical pendulum
Consider the spherical pendulum, a mass (known as a "pendulum bob") attached to a rigid rod of length of negligible mass, subject to a local gravitational field . The system rotates with angular velocity which is not constant. The angle between the rod and vertical is and is not constant.
The Lagrangian is
and is the cyclic coordinate for the system with constant momentum
which again is physically the angular momentum of the system about the vertical. The angle and angular velocity vary with time, but the angular momentum is constant. The Routhian is
The equation is found from the Lagrangian equations
or simplifying by introducing the constants
gives
This equation resembles the simple nonlinear pendulum equation, because it can swing through the vertical axis, with an additional term to account for the rotation about the vertical axis (the constant is related to the angular momentum ).
Applying the Lagrangian approach there are two nonlinear coupled equations to solve.
The equation is
and the equation is
Heavy symmetrical top
The heavy symmetrical top of mass has Lagrangian
where are the Euler angles, is the angle between the vertical -axis and the top's -axis, is the rotation of the top about its own -axis, and the azimuthal of the top's -axis around the vertical -axis. The principal moments of inertia are about the top's own axis, about the top's own axes, and about the top's own -axis. Since the top is symmetric about its -axis, . Here the simple relation for local gravitational potential energy is used where is the acceleration due to gravity, and the centre of mass of the top is a distance from its tip along its -axis.
The angles are cyclic. The constant momenta are the angular momenta of the top about its axis and its precession about the vertical, respectively:
From these, eliminating :
we have
and to eliminate , substitute this result into and solve for to find
The Routhian can be taken to be
and since
we have
The first term is constant, and can be ignored since only the derivatives of R will enter the equations of motion. The simplified Routhian, without loss of information, is thus
The equation of motion for is, by direct calculation,
or by introducing the constants
a simpler form of the equation is obtained
Although the equation is highly nonlinear, there is only one equation to solve for, it was obtained directly, and the cyclic coordinates are not involved.
By contrast, the Lagrangian approach leads to three nonlinear coupled equations to solve, despite the absence of the coordinates and in the Lagrangian.
The equation is
the equation is
and the equation is
Velocity-dependent potentials
Classical charged particle in a uniform magnetic field
Consider a classical charged particle of mass and electric charge in a static (time-independent) uniform (constant throughout space) magnetic field . The Lagrangian for a charged particle in a general electromagnetic field given by the magnetic potential and electric potential is
It is convenient to use cylindrical coordinates , so that
In this case of no electric field, the electric potential is zero, , and we can choose the axial gauge for the magnetic potential
and the Lagrangian is
Notice this potential has an effectively cylindrical symmetry (although it also has angular velocity dependence), since the only spatial dependence is on the radial length from an imaginary cylinder axis.
There are two cyclic coordinates, and . The canonical momenta conjugate to and are the constants
so the velocities are
The angular momentum about the z axis is not , but the quantity , which is not conserved due to the contribution from the magnetic field. The canonical momentum is the conserved quantity. It is still the case that is the linear or translational momentum along the z axis, which is also conserved.
The radial component and angular velocity can vary with time, but is constant, and since is constant it follows is constant. The Routhian can take the form
where in the last line, the term is a constant and can be ignored without loss of continuity. The Hamiltonian equations for and automatically vanish and do not need to be solved for. The Lagrangian equation in
is by direct calculation
which after collecting terms is
and simplifying further by introducing the constants
the differential equation is
To see how changes with time, integrate the momenta expression for above
where is an arbitrary constant, the initial value of to be specified in the initial conditions.
The motion of the particle in this system is helicoidal, with the axial motion uniform (constant) but the radial and angular components varying in a spiral according to the equation of motion derived above. The initial conditions on , , , , will determine if the trajectory of the particle has a constant or varying . If initially is nonzero but , while and are arbitrary, then the initial velocity of the particle has no radial component, is constant, so the motion will be in a perfect helix. If r is constant, the angular velocity is also constant according to the conserved .
With the Lagrangian approach, the equation for would include which has to be eliminated, and there would be equations for and to solve for.
The equation is
the equation is
and the equation is
The equation is trivial to integrate, but the and equations are not, in any case the time derivatives are mixed in all the equations and must be eliminated.
See also
Calculus of variations
Phase space
Configuration space
Many-body problem
Rigid body mechanics
Footnotes
Notes
References
Classical mechanics
Mathematical physics
Applied mathematics
ru:Функция Рауса | Routhian mechanics | Physics,Mathematics | 3,324 |
62,389,592 | https://en.wikipedia.org/wiki/Indentation%20size%20effect | The indentation size effect (ISE) is the observation that hardness tends to increase as the indent size decreases at small scales. When an indent (any small mark, but usually made with a special tool) is created during material testing, the hardness of the material is not constant. At the small scale, materials will actually be harder than at the macro-scale. For the conventional indentation size effect, the smaller the indentation, the larger the difference in hardness. The effect has been seen through nanoindentation and microindentation measurements at varying depths. Dislocations increase material hardness by increasing flow stress through dislocation blocking mechanisms. Materials contain statistically stored dislocations (SSD) which are created by homogeneous strain and are dependent upon the material and processing conditions. Geometrically necessary dislocations (GND) on the other hand are formed, in addition to the dislocations statistically present, to maintain continuity within the material.
These additional geometrically necessary dislocations (GND) further increase the flow stress in the material and therefore the measured hardness. Theory suggests that plastic flow is impacted by both strain and the size of the strain gradient experienced in the material. Smaller indents have higher strain gradients relative to the size of the plastic zone and therefore have a higher measured hardness in some materials.
For practical purposes this effect means that hardness in the low micro and nano regimes cannot be directly compared if measured using different loads. However, the benefit of this effect is that it can be used to measure the effects of strain gradients on plasticity. Several new plasticity models have been developed using data from indentation size effect studies, which can be applied to high strain gradient situations such as thin films.
References
Hardness tests
Materials science
Plasticity (physics) | Indentation size effect | Physics,Materials_science,Engineering | 368 |
13,247,256 | https://en.wikipedia.org/wiki/Nuclebr%C3%A1s%20Equipamentos%20Pesados | The Nuclebrás Equipamentos Pesados S.A., commonly shortned to NUCLEP, is a Brazilian state-owned nuclear company specialized in nuclear engineering and heavy equipment for nuclear, defense, oil and gas industries, founded on 12 April 1975.
See also
Goiânia accident (Nuclebrás aided in response effort)
National Nuclear Energy Commission
References
Manufacturing companies of Brazil
Companies based in Rio de Janeiro (state)
Manufacturing companies established in 1975
Engineering companies of Brazil
Defence companies of Brazil
Nuclear technology companies of Brazil
Brazilian companies established in 1975 | Nuclebrás Equipamentos Pesados | Physics | 116 |
54,480,633 | https://en.wikipedia.org/wiki/Institute%20for%20the%20History%20and%20Theory%20of%20Architecture | The Institute for the History and Theory of Architecture (; gta) is a teaching and research institute at the Department of Architecture of ETH Zurich, situated on the ETH Zurich’s Hönggerberg Campus site.
History
The Institute for the History and Theory of Architecture (gta) was founded on 1 January 1967 as a research body at the Architecture Department of ETH Zurich. The opening symposium was held on 23 June 1967.
Since its beginnings in 1967, the past and the present, theory and practice, have been the cornerstones and reference framework for the work undertaken at the Institute for the History and Theory of Architecture (gta). Besides teaching activities in the fields of the history of art and architecture, architectural theory and urban design, the institute’s core focus since its launch has lain in mediating and exploring architecture in its historical depth and thematic breadth.
The results of the institute’s in-house research, which is primarily influenced by the areas of interest of the teaching staff and the holdings of the simultaneously established archive, have been presented since 1968 in a publication series. These first appeared in cooperation with the Birkhäuser publishing house (in the “rainbow series”), later with the Ammann publishing house and since the mid-1980s in the gta Verlag, which today enjoys the reputation of being one of the leading architecture publishers.
The absorption of the so-called Semper Archive from the ETH Bibliothek on the occasion of the creation of the institute forms the foundation of the gta Archives, which over time has advanced to become an internationally renowned research facility.
Since then, the main acquisition emphasis has been on the architecture of the nineteenth century and the pre-modern, modern (Swiss) architecture in the form of collections (Congrès Internationaux d'Architecture Moderne (CIAM)), as well as advance legacies and bequests of individual architects of international stature (including Karl Moser, Hans Bernoulli, Lux Guyer, Haefeli Moser Steiger, Ernst Gisel, Fritz Haller and Trix and Robert Haussmann).
The organisational office for exhibitions by the ETH Zurich’s Department of Architecture became incorporated in the institute in 1974, and – since 1986 as gta Exhibitions – affords a wide public insight into contemporary architectural discourse and current research at the department.
Institute directors
Adolf Max Vogt (1920–2013), director from 1967 to 1974 and 1981 to 1982
Bernhard Hoesli (1923–1984), director from 1975 to 1980
Heinz Ronner (1924–1992), director from 1983 to 1987
Werner Oechslin (born 1944), director from 1987 to 1998 and 1999 to 2006
Kurt W. Forster (born 1935), director from 1998 to 1999
Andreas Tönnesmann (1953–2014), director from 2006 to 2010
Vittorio Magnago Lampugnani (born 1951), director from 2010 to 2016
Laurent Stalder (born 1970), director from 2016 to 2021
Tom Avermaete (born 1971), director from 2021 to 2024
Philip Ursprung (born 1963) director since 2024
Professorial chairs and divisions
Today the institute encompasses the following professorial chairs:
Chair of the History and Theory of Urban Design, Tom Avermaete
Chair of the History and Theory of Architecture, Maarten Delbeke
Chair of Theory of Architecture, Laurent Stalder
Chair of the History of Art and Architecture, Philip Ursprung
The following divisions assist the research projects and convey their findings:
gta Archives
gta Verlag
gta Exhibitions
gta Digital
The gta Institute assists in the promotion of academic newcomers with its own doctoral programme (since 2012). The institute’s educational provisions are supplemented by the programme Master of Studies in the History and Theory of Architecture, which mediates between practice and scholarship (since 1992).
There is a close academic exchange with the Werner Oechslin Library Foundation, associated with the ETH Zurich via a cooperation agreement.
Teaching and research areas
The institute's task is to empirically appraise and theoretically reflect upon architecture in its historical depth and ideological breadth. Along with the establishing and verification of facts, the gta Institute has always been at pains to review applied methods in terms of their validity as models and to make them beneficial to contemporary architecture. As an institute, the gta researches and teaches the history of knowledge of architecture, building forms and techniques, the function of architecture and its relations to society and politics, the evolution of design and architectural thinking from the beginnings to today, as well as the methodologies of architectural history work ranging from building analysis through to the digital humanities.
References
External links
Official website of the Institute for the History and Theory of Architecture
Digital Art History Image Database of the gta Institute, ETH Zurich
Architectural history
ETH Zurich | Institute for the History and Theory of Architecture | Engineering | 979 |
14,977,455 | https://en.wikipedia.org/wiki/Combination%20puzzle | A combination puzzle, also known as a sequential move puzzle, is a puzzle which consists of a set of pieces which can be manipulated into different combinations by a group of operations. Many such puzzles are mechanical puzzles of polyhedral shape, consisting of multiple layers of pieces along each axis which can rotate independently of each other. Collectively known as twisty puzzles, the archetype of this kind of puzzle is the Rubik's Cube. Each rotating side is usually marked with different colours, intended to be scrambled, then solved by a sequence of moves that sort the facets by colour. Generally, combination puzzles also include mathematically defined examples that have not been, or are impossible to, physically construct.
Description
A combination puzzle is solved by achieving a particular combination starting from a random (scrambled) combination. Often, the solution is required to be some recognisable pattern such as "all like colours together" or "all numbers in order". The most famous of these puzzles is the original Rubik's Cube, a cubic puzzle in which each of the six faces can be independently rotated. Each of the six faces is a different colour, but each of the nine pieces on a face is identical in colour in the solved condition. In the unsolved condition, colours are distributed amongst the pieces of the cube. Puzzles like the Rubik's Cube which are manipulated by rotating a section of pieces are popularly called twisty puzzles. They are often face-turning, but commonly exist in corner-turning and edge-turning varieties.
The mechanical construction of the puzzle will usually define the rules by which the combination of pieces can be altered. This leads to some limitations on what combinations are possible. For instance, in the case of the Rubik's Cube, there are a large number of combinations that can be achieved by randomly placing the coloured stickers on the cube, but not all of these can be achieved by manipulating the cube rotations. Similarly, not all the combinations that are mechanically possible from a disassembled cube are possible by manipulation of the puzzle. Since neither unpeeling the stickers nor disassembling the cube is an allowed operation, the possible operations of rotating various faces limit what can be achieved.
Although a mechanical realization of the puzzle is usual, it is not actually necessary. It is only necessary that the rules for the operations are defined. The puzzle can be realized entirely in virtual space or as a set of mathematical statements. In fact, there are some puzzles that can only be realized in virtual space. An example is the 4-dimensional 3×3×3×3 tesseract puzzle, simulated by the MagicCube4D software.
Types
There have been many different shapes of Rubik type puzzles constructed. As well as cubes, all of the regular polyhedra and many of the semi-regular and stellated polyhedra have been made.
Regular cuboids
A cuboid is a rectilinear polyhedron. That is, all its edges form right angles. Or in other words (in the majority of cases), a box shape. A regular cuboid, in the context of this article, is a cuboid puzzle where all the pieces are the same size in edge length. Pieces are often referred to as "cubies".
Pattern variations
There are many puzzles which are mechanically identical to the regular cuboids listed above but have variations in the pattern and colour of design. Some of these are custom made in very small numbers, sometimes for promotional events. The ones listed in the table below are included because the pattern in some way affects the difficulty of the solution or is notable in some other way.
Sudoku Cube
The Sudoku Cube or Sudokube is a variation on a Rubik's Cube in which the aim is to solve one or more Sudoku puzzles on the sides or rows. The toy was originally created in 2006 by Jay Horowitz in Sebring, Ohio. It was subsequently produced in China, marketed and sold internationally.
Production
The Sudoku Cube was invented by veteran toy maker Jay Horowitz, a puzzle inventor who primarily reproduced older toys for the collectibles market. Horowitz first encountered the original Sudoku puzzle when a woman sitting next to him on a plane ride explained it to him. After being introduced to the puzzle, Horowitz wanted to introduce the puzzle to the games business, and had the idea of combining it with the Rubik's cube. Horowitz already had access to molds for the Rubik's Cube, as he owned the Ideal Toy Company which owned molds. Horowitz worked for a month until he figured out how to combine the two puzzles together, and then when he figured it out, he "did not sleep for three days" while he worked out how to best arrange the numbers to create 18 unique Sudoku puzzles within the cube. Horowitz then patented the numerical design that he created. Mass production was completed in China by American Classic Toy Inc, a company belonging to Horowitz. The product was sold in the United States in retailers such as Barnes & Noble and FAO Schwarz and sold for $9.87 each. The price was chosen specifically because each number only appears once.
Marketing
Horowitz promoted his new product in at toy fairs such as the 2007 American International Toy Fair and Hong Kong Toys and Games Fair. Adrienne Citrin, the spokeswoman for the Toy Industry Association, mentioned that Sudoku fans who felt like they had mastered the original paper version of the puzzle were interested in the new product. The product was originally launched in the US and then sold internationally, exporting to Spain, France, South Africa and the United Kingdom. Shortly after release, there were several imitator products sold on Amazon under the name "Sudokube".
Irregular cuboids
An irregular cuboid, in the context of this article, is a cuboid puzzle where not all the pieces are the same size in edge length. This category of puzzle is often made by taking a larger regular cuboid puzzle and fusing together some of the pieces to make larger pieces. In the formulae for piece configuration, the configuration of the fused pieces is given in brackets. Thus, (as a simple regular cuboid example) a 2(2,2)x2(2,2)x2(2,2) is a 2×2×2 puzzle, but it was made by fusing a 4×4×4 puzzle. Puzzles which are constructed in this way are often called "bandaged" cubes. However, there are many irregular cuboids that have not (and often could not) be made by bandaging.
Other polyhedra
Non-Rubik style three-dimensional
Two-dimensional
Geared puzzles
See also
N-dimensional sequential move puzzles
Puck puzzle
List of Rubik's Cube manufacturers
References
External links
A large database of twisty puzzles
The Puzzle Museum
The Magic Polyhedra Patent Page
Puzzles
Mechanical puzzles | Combination puzzle | Mathematics | 1,416 |
30,133,280 | https://en.wikipedia.org/wiki/Otidea%20leporina | Otidea leporina is a species of fungus in the family Pyronemataceae. It was given its current name by Karl Wilhelm Gottlieb Leopold Fuckel in 1870. It contains toxins which may cause serious gastric upset.
References
External links
Fungi described in 1783
Poisonous fungi
Pyronemataceae
Taxa named by August Batsch
Fungus species | Otidea leporina | Biology,Environmental_science | 75 |
24,942 | https://en.wikipedia.org/wiki/Patrilineality | Patrilineality, also known as the male line, the spear side or agnatic kinship, is a common kinship system in which an individual's family membership derives from and is recorded through their father's lineage. It generally involves the inheritance of property, rights, names, or titles by persons related through male kin. This is sometimes distinguished from cognate kinship, through the mother's lineage, also called the spindle side or the distaff side.
A patriline ("father line") is a person's father, and additional ancestors, as traced only through males.
In the Bible
In the Bible, family and tribal membership appears to be transmitted through the father. For example, a person is considered to be a priest or Levite, if his father is a priest or Levite, and the members of all the Twelve Tribes are called Israelites because their father is Israel (Jacob).
In the first lines of the New Testament, the descent of Jesus Christ from King David is counted through the male lineage.
Agnatic succession
Patrilineal or agnatic succession gives priority to or restricts inheritance of a throne or fief to male heirs descended from the original title holder through males only. Traditionally, agnatic succession is applied in determining the names and membership of European dynasties. The prevalent forms of dynastic succession in Europe, Asia and parts of Africa were male-preference primogeniture, agnatic primogeniture, or agnatic seniority until after World War II. The agnatic succession model, also known as Salic law, meant the total exclusion of women as hereditary monarchs and restricted succession to thrones and inheritance of fiefs or land to men in parts of medieval and later Europe. This form of strict agnatic inheritance has been officially revoked in all extant European monarchies except the Principality of Liechtenstein.
By the 21st century, most ongoing European monarchies had replaced their traditional agnatic succession with absolute primogeniture, meaning that the first child born to a monarch inherits the throne, regardless of the child's sex.
Genetic genealogy
The fact that human Y-chromosome DNA (Y-DNA) is paternally inherited enables patrilines and agnatic kinships of men to be traced through genetic analysis.
Y-chromosomal Adam (Y-MRCA) is the patrilineal most recent common ancestor from whom all Y-DNA in living men is descended. An identification of a very rare and previously unknown Y-chromosome variant in 2012 led researchers to estimate that Y-chromosomal Adam lived 338,000 years ago (237,000 to 581,000 years ago with 95% confidence), judging from molecular clock and genetic marker studies. Before this discovery, estimates of the date when Y-chromosomal Adam lived were much more recent, estimated to be tens of thousands of years.
See also
Agnatic seniority
Cadet branch
Derbfine
Family name
Historical inheritance systems
Hypodescent
Hyperdescent
Matrilineality
Matriname
Order of succession
Patricide
Patrilocal residence
Primogeniture
Royal and noble ranks
Y chromosome
References
External links
Kinship and descent
Patriarchy
Order of succession | Patrilineality | Biology | 662 |
41,506 | https://en.wikipedia.org/wiki/Personal%20mobility | In Universal Personal Telecommunications (UPT), personal mobility is the ability of a user to access telecommunication services at any UPT terminal on the basis of a personal identifier, and the capability of the network to provide those services in accord with the user's service profile.
Personal mobility involves the network's capability to locate the terminal associated with the user for the purposes of addressing, routing, and charging the user for calls. "Access" is intended to convey the concepts of both originating and terminating services. Management of the service profile by the user is not part of personal mobility. The personal mobility aspects of personal communications are based on the UPT number.
References
Telephone numbers | Personal mobility | Mathematics | 138 |
62,624,537 | https://en.wikipedia.org/wiki/Epichlo%C3%AB%20novae-zelandiae | Epichloë novae-zelandiae is a hybrid asexual species in the fungal genus Epichloë.
A systemic and seed-transmissible grass symbiont first described in 2019, Epichloë novae-zelandiae is a natural triploid allopolyploid of Epichloë amarillans, Epichloë bromicola and Epichloë typhina subsp. poae.
Epichloë novae-zelandiae is found in New Zealand, where it has been identified in the grass species Poa matthewsii.
References
novae-zelandiae
Fungi described in 2019
Fungi of New Zealand
Fungus species | Epichloë novae-zelandiae | Biology | 134 |
62,086,726 | https://en.wikipedia.org/wiki/George%20Douglas%20of%20Parkhead | George Douglas of Parkhead, (died 1602), was a Scottish landowner, mining entrepreneur, Provost of Edinburgh, and Keeper of Edinburgh Castle.
Career
George Douglas was a son of George Douglas of Pittendreich, the name of his mother is unknown. His half-sister, Elizabeth, daughter of Lady Dundas, married Smeton Richeson. He married Marioun Douglas, heiress of Parkhead or Parkheid, and so became known as George Douglas of Parkhead. Parkhead is close to the Lanarkshire town of Douglas. He was later Provost of Edinburgh.
Refortification of Edinburgh Castle
After Edinburgh Castle was recovered from William Kirkcaldy of Grange in May 1573, George Douglas was appointed its Captain or keeper by his half-brother Regent Morton. George Douglas supervised the rebuilding of part of the back wall and other repairs, buying lime, sand, slate and glass. Part of the running expenses, or "sustenation" of the castle was paid to Douglas from the customs of Edinburgh town by Robert Gourlay.
Parkhead is credited with building the half-moon battery at Edinburgh castle, the Historie of King James the Sext records that Regent Morton appointed him captain, and caused "masonis to begin to redd (clear away) the bruisit wallis, and to repaire the foirwark to the forme of ane bulwark, platt and braid above, for the resett and ryving (receiving) of many canonis." Some building accounts from this work survive.
Douglas and Regent Morton
Douglas prospered during the regency of his brother, James Douglas, 4th Earl of Morton, and his servant Florence Douglas was made Rothesay Herald. When his brother resigned the regency of Scotland in March 1579, George Douglas of Parkhead made an inventory of the personal jewellery of Mary, Queen of Scots kept in Edinburgh Castle, and of the textiles, the royal tapestries, Mary's remaining costume, her pictures, dolls, and library, and he itemised the artillery of the castle and the tools in its workshops. The taking of this inventory was described in the chronicle attributed to David Moysie.
Douglas was involved in lead mining at Wanlockhead and Glengonnar or Leadhills in Lanarkshire and in Orkney. In June 1581 his interest in the lead mines with all the lead ore recovered was confiscated and given to James Stewart, Earl of Arran because he had withheld Torthorwald Castle from the earl.
Parkhead wrote to Francis Walsingham in June 1582 to thank him for hospitality in England, mentioning his friend John Selby of the garrison of Berwick-upon-Tweed. He had written to Selby in May 1582 describing a rumour that James VI would be sent to France.
In August 1584 George Douglas and his sons James and George were declared traitors and their goods and lands forfeited for their role "art and part" in the Raid of Stirling in April 1584.
Norway
James VI of Scotland sailed to Norway to meet his bride Anna of Denmark in October 1589. George Douglas of Parkhead was one of his companions. He wrote from Oslo to the Earl of Morton on 30 November 1589. The king had decided to stay over winter at the Danish court, and the Earl's son Archibald Douglas had decided to go travelling. He had asked Parkhead to go with him.
Later life
After their kinsman William Douglas, 6th Earl of Morton had been imprisoned in their keeping at Edinburgh Castle, Marion Douglas wrote to his wife Agnes Leslie, Countess of Morton to thank her for a gift of cheese from her farms at Fossoway near Lochleven Castle. She said that Morton had "received but very simple entertainment here".
Another of Marion Douglas's letters concerns the lead mines. On 6 August 1592 she wrote from Parkhead to Lord Menmuir asking for his decision about the mining concessions between Eustachius Roche and her husband. She had been obliged to order her miners to suspend working, putting them to other work or laying them off.
On 20 December 1593 George Douglas and his son James made over some of their lead mining rights in Glengonnar to the goldsmith and financier Thomas Foulis.
An English prospector Stephen Atkinson writing in 1619 stated that "George Parkhead" was killed by a landslide in wet weather at a mine working at "Short-clough brayes". It took three days to dig him out. The Shortcleuch water joins the Elvan and falls into the Clyde. Some sources suggest the victim of this accident was a son of George Douglas of Parkhead, and it occurred in 1586 while he was prospecting for gold.
George Douglas of Parkhead's will was registered in Edinburgh in 1602. It mentions oats stored in the barn yard of "Auld Foulden".
Family
The children of George Douglas and Marion Douglas included;
James Douglas of Parkhead (d. 1608), who married Elizabeth Carlyle, daughter of William, Master of Carlyle. She was an heiress and the marriage was probably arranged by Regent Morton. It was said that he was cruel to her. On 2 November 1596 James Douglas of Parkhead and his accomplices killed his father's enemy, James Stewart, former Earl of Arran at Symington. They claimed that Stewart was technically a rebel, "at the horn". As his tombstone at Holyrood Abbey mentions, James Douglas was killed on the Royal Mile Edinburgh on 14 July 1608, by Captain William Stewart, son of William Stewart of Monkton and a nephew of Arran. Elizabeth Carlyle then married William Sinclair of Blaas.
The children of James Douglas and Elizabeth Carlyle included; James Douglas, who married (1) Elizabeth Gordon of Lochinvar, (2) Anne Saltonstall, daughter of Richard Saltonstall, Lord Mayor of London.
George Douglas of Mordington, who married Margaret Dundas, daughter of Archibald Dundas of Fingask, and sister of William Dundas who wrote letters commenting on the court of Anne of Denmark in 1590 and painted ceilings in 1593. She was the widow of William Kerr of Ancram, and mother of the courtier Robert Kerr.
The children of George Douglas and Margaret Dundas included; George Douglas ambassador to Poland and Sweden for Charles I of England; and Margaret Douglas who married Sir James Lockhart of Lee, her children included William Lockhart who was ambassador to France for Oliver Cromwell; George Lockhart a lawyer; and Anne Lockhart who married George Lockhart of Tarbrax.
John Douglas, minister of Crail.
Catherine Douglas, who married Sir James Dundas of Arniston, governor of Berwick upon Tweed after 1603.
Margaret Douglas, who married (1) Edward Sinclair of Roslynn and Herbertshire, (2) Sir Patrick Home of Ayton.
Martha Douglas, who married Robert Bruce, minister of Edinburgh. Their betrothal ring was kept by the Bruce family of Kinnaird, Stirlingshire.
Mary Douglas, who married John Carruthers of Holmains in Annandale.
References
External links
Two Letters about Cheese: Marion Douglas, Lady Parkhead
Scheduled Monument: Gold scours, cut into the hillside above the Shortcleuch Water, SM13677, Historic Environment Scotland
History of Leadhills, Leadhills Estate.
Robert William Cochran-Patrick, Early Records Relating to Mining in Scotland (Edinburgh, 1878)
16th-century Scottish people
16th-century births
Year of birth unknown
1602 deaths
Lord provosts of Edinburgh
Mining engineers
Scottish mining engineers
Gold mines in Scotland
16th-century Scottish businesspeople
Lairds | George Douglas of Parkhead | Engineering | 1,570 |
8,053,931 | https://en.wikipedia.org/wiki/Mobile%20ticketing | Mobile ticketing is the process whereby customers order, pay for, obtain, and validate tickets using mobile phones. A mobile ticket contains a verification unique to the holder's phone. Mobile tickets reduce the production and distribution costs associated with paper-based ticketing for operators by transferring the burden to the customer, who is required to contribute the cost of the physical device (smartphone) and internet access to the process. As a result of these prerequisites, and in contrast to paper-based systems, mobile ticketing does not follow the principles of universal design.
Mobile tickets should not be confused with e-tickets, which are simply tickets issued in electronic form, independent of a specific device and in a standard, intelligible format, that can be printed and used in paper form. While a mobile phone is compatible with an e-ticket, mobile ticketing is a distinct system.
There are several methods of implementing a mobile ticketing system, with varying degrees of complexity and transparency depending on the underlying technology. Mobile tickets may lessen the potential for scalping (touting) and fraud.
History
The QR code was created by a subsidiary of the Japanese automotive company Denso in 1994. Philips and Sony developed near-field communication (NFC) in 2002. It is based on radio-frequency identification (RFID) technology and enables short-range communication between electronic devices. Philips published an early paper on NFC in 2004, while the NFC Forum was established in the same year. The GSMA published a whitepaper on M-Ticketing in 2011, having commissioned research to examine the opportunities for network operators in a mobile ticketing market. The research was focused on a specific NFC system based on the UICC, which is owned and controlled by the network operator that issues it, and other technologies such as SMS and barcode were given passing consideration in the report.
The first mobile ticketing deployment for a public transport operator in the UK was for Chiltern Railways in 2007. The first transit agency in the US to deploy mobile ticketing was Boston's MBTA in 2012, while the first system in Australia was Adelaide Metro in 2017.
The New York Yankees partnered with Ticketmaster in 2015 and adopted a new ticketing policy the following year. The option of a print-at-home e-ticket (PDF), which was popular among fans for its convenience, was replaced by a mobile ticketing system. In 2017, the state of Connecticut passed a law that requires venues to make printed, paper tickets available to customers and provide a means to transfer tickets without restrictions.
In 2019, a mobile-only ticketing system developed by Ticketmaster was installed in stadiums across the NFL, based on the Presence platform developed by the company in 2017. The platform is an access control system and marketing tool involving personalized digital tickets and tracking software. The mobile-only version of the system, SafeTix, links the tickets to individual smartphones and was adopted by the vast majority of NFL franchises due to Ticketmaster's position as primary ticket partner of the league. The Buffalo Bills received praise from several organizations, including the NAACP, for not adopting mobile-only ticketing, while fans across the league experienced delays and refusals of entry due to a range of issues with the system.
The All England Club implemented mobile ticketing with an online-only ballot and a ban on ticket transfers for the 2021 Wimbledon Championships, citing COVID-19 protocols developed by the SGSA. The policy was criticized by Age UK for lacking an offline option. A number of Premier League clubs adopted a mobile-only policy for the 2021–22 season, resulting in problems accessing their respective grounds and pushback from supporters' groups. Liverpool F.C. gave its fans the option of a photographic smart card for those without an NFC-enabled phone. ID cards of any form are controversial among football supporters and have been rejected by English fans in the past.
For the 2021 season, the NFL is mandating mobile-only ticketing across the league. The mandate removes the option to issue paper tickets for the few franchises that had not enforced a mobile-only policy, and codifies the requirement for every fan to own a smartphone and grant access to it in order to attend a game. A fifth of Americans do not own a smartphone, either by choice or due to constraint.
Methods
There are several methods of implementing a mobile ticketing system, depending on the technology used. In a system based on text messaging, the user receives their ticket in the form of either an alphanumeric code or a barcode. In a process based on a mobile application, the user carries out a transaction through the app and receives a verification, such as a QR code, specific to their account. Where NFC technology is used, a ticket is issued in the form of a discreet token generated by emulation software on the user's phone itself.
Privacy and transparency
The operation of a mobile ticketing system raises issues of privacy and security. The harvesting of personal data points enables an operator to model, predict, and potentially modify, the behavior of a customer. The implementation of OMNY, a contactless fare payment system for public transport in New York City, has provoked a number of concerns related to surveillance, data security, and transparency in the usage of passengers' information. The system, which uses NFC technology, collects significant amounts of user data, including device identifiers and IP addresses, locations of entry, billing addresses, and payment information.
See also
Contactless smart card
Appropriate technology
Mobile payment
Multimedia Messaging Service
References
Mobile technology
Travel technology
Tickets | Mobile ticketing | Technology | 1,130 |
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