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This article contains a list of sample Hilbert-style deductive systems for propositional logics .
Classical propositional calculus is the standard propositional logic. Its intended semantics is bivalent and its main property is that it is strongly complete , otherwise said that whenever a formula semantically follows from a set of premises, it also follows from that set syntactically. Many different equivalent complete axiom systems have been formulated. They differ in the choice of basic connectives used, which in all cases have to be functionally complete (i.e. able to express by composition all n -ary truth tables ), and in the exact complete choice of axioms over the chosen basis of connectives.
The formulations here use implication and negation { → , ¬ } {\displaystyle \{\to ,\neg \}} as functionally complete set of basic connectives. Every logic system requires at least one non-nullary rule of inference . Classical propositional calculus typically uses the rule of modus ponens :
We assume this rule is included in all systems below unless stated otherwise.
Frege 's axiom system: [ 1 ]
Hilbert 's axiom system: [ 1 ]
Łukasiewicz 's axiom systems: [ 1 ]
Arai 's axiom system: [ 2 ]
Łukasiewicz and Tarski 's axiom system: [ 3 ]
Meredith 's axiom system:
Mendelson 's axiom system: [ 4 ]
Russell 's axiom system: [ 1 ]
Sobociński 's axiom systems: [ 1 ]
Instead of negation, classical logic can also be formulated using the functionally complete set { → , ⊥ } {\displaystyle \{\to ,\bot \}} of connectives.
Tarski– Bernays – Wajsberg axiom system:
Church 's axiom system:
Meredith's axiom systems:
Instead of implication, classical logic can also be formulated using the functionally complete set { ¬ , ∨ } {\displaystyle \{\neg ,\lor \}} of connectives. These formulations use the following rule of inference;
Russell–Bernays axiom system:
Meredith's axiom systems: [ 9 ]
Dually, classical propositional logic can be defined using only conjunction and negation.
Rosser J. Barkley created a system based on conjunction and negation { ∧ , ¬ } {\displaystyle \{\wedge ,\neg \}} , with the modus ponens as inference rule. In his book, [ 10 ] he used the implication to present his axiom schemes. " C → D {\displaystyle C\rightarrow D} " is an abbreviation for " ¬ ( C ∧ ¬ D ) {\displaystyle \neg (C\wedge \neg D)} ":
If we don't use the abbreviation, we get the axiom schemes in the following form:
Also, modus ponens becomes:
Because Sheffer's stroke (also known as NAND operator) is functionally complete , it can be used to create an entire formulation of propositional calculus. NAND formulations use a rule of inference called Nicod 's modus ponens:
Nicod's axiom system: [ 6 ]
Łukasiewicz's axiom systems: [ 6 ]
Wajsberg's axiom system: [ 6 ]
Argonne axiom systems: [ 6 ]
Computer analysis by Argonne has revealed over 60 additional single axiom systems that can be used to formulate NAND propositional calculus. [ 8 ]
The implicational propositional calculus is the fragment of the classical propositional calculus which only admits the implication connective. It is not functionally complete (because it lacks the ability to express falsity and negation) but it is however syntactically complete . The implicational calculi below use modus ponens as an inference rule.
Bernays–Tarski axiom system: [ 12 ]
Łukasiewicz and Tarski's axiom systems:
Łukasiewicz's axiom system: [ 13 ] [ 12 ]
Intuitionistic logic is a subsystem of classical logic. It is commonly formulated with { → , ∧ , ∨ , ⊥ } {\displaystyle \{\to ,\land ,\lor ,\bot \}} as the set of (functionally complete) basic connectives. It is not syntactically complete since it lacks excluded middle A∨¬A or Peirce's law ((A→B)→A)→A which can be added without making the logic inconsistent. [ disputed (for: These principles can be added to intuitionistic logic, but doing so effectively turns it into classical logic.) – discuss ] It has modus ponens as inference rule, and the following axioms:
Alternatively, intuitionistic logic may be axiomatized using { → , ∧ , ∨ , ¬ } {\displaystyle \{\to ,\land ,\lor ,\neg \}} as the set of basic connectives, replacing the last axiom with
Intermediate logics are in between intuitionistic logic and classical logic. Here are a few intermediate logics:
The positive implicational calculus is the implicational fragment of intuitionistic logic. The calculi below use modus ponens as an inference rule.
Łukasiewicz's axiom system:
Meredith's axiom systems:
Hilbert's axiom systems:
Positive propositional calculus is the fragment of intuitionistic logic using only the (non functionally complete) connectives { → , ∧ , ∨ } {\displaystyle \{\to ,\land ,\lor \}} . It can be axiomatized by any of the above-mentioned calculi for positive implicational calculus together with the axioms
Optionally, we may also include the connective ↔ {\displaystyle \leftrightarrow } and the axioms
Johansson 's minimal logic can be axiomatized by any of the axiom systems for positive propositional calculus and expanding its language with the nullary connective ⊥ {\displaystyle \bot } , with no additional axiom schemas. Alternatively, it can also be axiomatized in the language { → , ∧ , ∨ , ¬ } {\displaystyle \{\to ,\land ,\lor ,\neg \}} by expanding the positive propositional calculus with the axiom
or the pair of axioms
Intuitionistic logic in language with negation can be axiomatized over the positive calculus by the pair of axioms
or the pair of axioms [ 16 ]
Classical logic in the language { → , ∧ , ∨ , ¬ } {\displaystyle \{\to ,\land ,\lor ,\neg \}} can be obtained from the positive propositional calculus by adding the axiom
or the pair of axioms
Fitch calculus takes any of the axiom systems for positive propositional calculus and adds the axioms [ 16 ]
Note that the first and third axioms are also valid in intuitionistic logic.
Equivalential calculus is the subsystem of classical propositional calculus that only allows the (functionally incomplete) equivalence connective, denoted here as ≡ {\displaystyle \equiv } . The rule of inference used in these systems is as follows:
Iséki's axiom system: [ 17 ]
Iséki–Arai axiom system: [ 18 ]
Arai's axiom systems;
Łukasiewicz's axiom systems: [ 19 ]
Meredith's axiom systems: [ 19 ]
Kalman 's axiom system: [ 19 ]
Winker 's axiom systems: [ 19 ]
XCB axiom system: [ 19 ] | https://en.wikipedia.org/wiki/List_of_axiomatic_systems_in_logic |
This is a list of axioms as that term is understood in mathematics . In epistemology , the word axiom is understood differently; see axiom and self-evidence . Individual axioms are almost always part of a larger axiomatic system .
Together with the axiom of choice (see below), these are the de facto standard axioms for contemporary mathematics or set theory . They can be easily adapted to analogous theories, such as mereology .
See also Zermelo set theory .
With the Zermelo–Fraenkel axioms above, this makes up the system ZFC in which most mathematics is potentially formalisable. | https://en.wikipedia.org/wiki/List_of_axioms |
The following is an incomplete list of backmasked messages in music. | https://en.wikipedia.org/wiki/List_of_backmasked_messages |
In organic chemistry the addition of the prefix benzo to the name of a chemical compound indicates the addition of an even number of carbon atoms to an unsaturated or already aromatic compound by which a new aromatic ring is formed. Between the prefix benzo and the name of the parent compound then place of the addition of the extra carbon atoms is indicated by letters written between square brackets. [ 1 ] Quite often the number of added carbon atoms is four, although sometimes two else will do the job as shown in the following table. The first entry also shows different routes to the name of the same molecule. | https://en.wikipedia.org/wiki/List_of_benzo_compounds |
This is a list of some binary codes that are (or have been) used to represent text as a sequence of binary digits "0" and "1". Fixed-width binary codes use a set number of bits to represent each character in the text, while in variable-width binary codes, the number of bits may vary from character to character.
Several different five-bit codes were used for early punched tape systems.
Five bits per character only allows for 32 different characters, so many of the five-bit codes used two sets of characters per value referred to as FIGS (figures) and LTRS (letters), and reserved two characters to switch between these sets. This effectively allowed the use of 60 characters.
Standard five-bit standard codes are:
The following early computer systems each used its own five-bit code:
The steganographic code, commonly known as Bacon's cipher uses groups of 5 binary-valued elements to represent letters of the alphabet.
Six bits per character allows 64 distinct characters to be represented.
Examples of six-bit binary codes are:
See also: Six-bit character codes
Examples of seven-bit binary codes are:
Data compression systems such as Lempel–Ziv–Welch can compress arbitrary binary data. They are therefore not binary codes themselves but may be applied to binary codes to reduce storage needs. | https://en.wikipedia.org/wiki/List_of_binary_codes |
The following is a list of some referenced bioacoustics software . | https://en.wikipedia.org/wiki/List_of_bioacoustics_software |
This list of biochemistry awards is an index to articles on notable awards for contributions to biochemistry , the study of chemical processes within and relating to living organisms. The list gives the country of the organization that gives the award, but the award may not be limited to people from that country. | https://en.wikipedia.org/wiki/List_of_biochemistry_awards |
This is a list of biochemists . It should include those who have been important to the development or practice of biochemistry. Their research or applications have made significant contributions in the area of basic or applied biochemistry.
Scientists in fields close to biochemistry | https://en.wikipedia.org/wiki/List_of_biochemists |
This article provides a list of sites in the United Kingdom which are recognised for their importance to biodiversity conservation . The list is divided geographically by region and county.
England Southwest • Southeast • Midlands • East Anglia • Northwest • Northeast Wales Scotland See also
Sites are included in this list if they are given any of the following designations:
Sites of importance in a global context
Sites of importance in a European context
Sites of importance in a national context
Rye Harbour Nature Reserve | https://en.wikipedia.org/wiki/List_of_biodiversity_conservation_sites_in_the_United_Kingdom |
This is a list of biodiversity databases . Biodiversity databases store taxonomic information alone or more commonly also other information like distribution (spatial) data and ecological data, which provide information on the biodiversity of a particular area or group of living organisms. They may store specimen-level information, species-level information, information on nomenclature, or any combination of the above. Most are available online.
Specimen-focused databases contain data about individual specimens, as represented by vouchered museum specimens, collections of specimen photographs, data on field-based specimen observations and morphological or genetic data. Species-focused databases contain information summarised at the species-level. Some species-focused databases attempt to compile comprehensive data about particular species ( FishBase ), while others focus on particular species attributes, such as checklists of species in a given area (FEOW) or the conservation status of species ( CITES or IUCN Red List ). Nomenclators act as summaries of taxonomic revisions and set a key between specimen-focused and species-focused databases. They do this because taxonomic revisions use specimen data to determine species limits. | https://en.wikipedia.org/wiki/List_of_biodiversity_databases |
This page features a list of biogeographic provinces that were developed by Miklos Udvardy in 1975, [ 1 ] [ 2 ] later modified by other authors. [ according to whom? ] Biogeographic Province is a biotic subdivision of biogeographic realms subdivided into ecoregions , which are classified based on their biomes or habitat types and, on this page, correspond to the floristic kingdoms of botany.
The provinces represent the large areas of Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from one another by geographic features, such as oceans, broad deserts, or high mountain ranges, that constitute barriers to migration.
Biomes are characterized by similar climax vegetation , though each realm may include a number of different biomes. A tropical moist broadleaf forest in Brazil, for example, may be similar to one in New Guinea in its vegetation type and structure, climate, soils, etc., but these forests are inhabited by plants with very different evolutionary histories.
The hierarchy of the scheme is (with early replaced terms in parentheses): [ 1 ]
So, for example, the Australian Central Desert province is in the Australasian realm (6), is the 9th biogeographic province in that realm, and its biome falls within "warm deserts and semideserts" (7), so it is coded 6.9.7.
The realms and provinces of the scheme are hence coded as follows: | https://en.wikipedia.org/wiki/List_of_biogeographic_provinces |
This is a list of taxa whose location or distribution is notably difficult to explain; e.g., species which came to occupy a range distant from that of their closest relatives by a process or history that is not understood, or is a subject of controversy. | https://en.wikipedia.org/wiki/List_of_biogeographical_puzzles |
This is a list of notable peer-reviewed scientific journals that focus on bioinformatics and computational biology . | https://en.wikipedia.org/wiki/List_of_bioinformatics_journals |
The following is a list of terms used to describe biological disorders of development, arranged by root word and shared prefix: | https://en.wikipedia.org/wiki/List_of_biological_development_disorders |
Bioluminescence is the production of light by living organisms. The environment organizes this list of bioluminescent organisms, covering terrestrial, marine, and microorganisms. | https://en.wikipedia.org/wiki/List_of_bioluminescent_organisms |
This is a list of articles that describe particular biomolecules or types of biomolecules.
For substances with an A- or α- prefix such as α-amylase , please see the parent page (in this case Amylase ).
For substances with an l- or L- prefix such as L-alanine or DL-alanine, please see the parent page (in this case alanine ). | https://en.wikipedia.org/wiki/List_of_biomolecules |
Crystal structures of protein and nucleic acid molecules and their complexes are central to the practice of most parts of biophysics , and have shaped much of what we understand scientifically at the atomic-detail level of biology. Their importance is underlined by the United Nations declaring 2014 as the International Year of Crystallography , as the 100th anniversary of Max von Laue 's 1914 Nobel Prize for discovering the diffraction of X-rays by crystals. This chronological list of biophysically notable protein and nucleic acid structures is loosely based on a review in the Biophysical Journal . [ 1 ] The list includes all the first dozen distinct structures, those that broke new ground in subject or method, and those that became model systems for work in future biophysical areas of research.
1958 – Myoglobin was the very first crystal structure of a protein molecule. [ 2 ] Myoglobin cradles an iron-containing heme group that reversibly binds oxygen for use in powering muscle fibers, and those first crystals were of myoglobin from the sperm whale , whose muscles need copious oxygen storage for deep dives. The myoglobin 3-dimensional structure is made up of 8 alpha-helices , and the crystal structure showed that their conformation was right-handed and very closely matched the geometry proposed by Linus Pauling , with 3.6 residues per turn and backbone hydrogen bonds from the peptide NH of one residue to the peptide CO of residue i+4. Myoglobin is a model system for many types of biophysical studies, [ 3 ] especially involving the binding process of small ligands such as oxygen and carbon monoxide .
1960 – The hemoglobin crystal structure [ 4 ] showed a tetramer of two related chain types and was solved at much lower resolution than the monomeric myoglobin, but it clearly had the same basic 8-helix architecture (now called the "globin fold"). Further hemoglobin crystal structures at higher resolution (PDB 1MHB, 1DHB) soon showed the coupled change of both local and quaternary conformation between the oxy and deoxy states of hemoglobin, [ 5 ] which explains the cooperativity of oxygen binding in the blood and the allosteric effect of factors such as pH and DPG . For decades hemoglobin was the primary teaching example for the concept of allostery, as well as being an intensive focus of research and discussion on allostery. In 1909, hemoglobin crystals from >100 species were used to relate taxonomy to molecular properties. [ 6 ] That book was cited by Perutz in the 1938 report [ 7 ] of horse hemoglobin crystals that began his long saga to solve the crystal structure. Hemoglobin crystals are pleochroic — dark red in two directions and pale red in the third [ 6 ] — because of the orientation of the hemes, and the bright Soret band of the heme porphyrin groups is used in spectroscopic analysis of hemoglobin ligand binding.
1965 – Hen-egg-white lysozyme (PDB file 1lyz). [ 8 ] was the first crystal structure of an enzyme (it cleaves small carbohydrates into simple sugars), used for early studies of enzyme mechanism. [ 9 ] It contained beta sheet (antiparallel) as well as helices, and was also the first macromolecular structure to have its atomic coordinates refined (in real space). [ 10 ] The starting material for preparation can be bought at the grocery store, and hen-egg lysozyme crystallizes very readily in many different space groups ; it is the favorite test case for new crystallographic experiments and instruments. Recent examples are nanocrystals of lysozyme for free-electron laser data collection [ 11 ] and microcrystals for micro electron diffraction. [ 12 ]
1967 – Ribonuclease A (PDB file 2RSA) [ 13 ] is an RNA-cleaving enzyme stabilized by 4 disulfide bonds. It was used in Anfinsen 's seminal research on protein folding which led to the concept that a protein's 3-dimensional structure was determined by its amino-acid sequence. Ribonuclease S , the cleaved, two-component form studied by Fred Richards , was also enzymatically active, had a nearly identical crystal structure (PDB file 1RNS), [ 14 ] and was shown to be catalytically active even in the crystal, [ 15 ] helping dispel doubts about the relevance of protein crystal structures to biological function.
1967 – The serine proteases are a historically very important group of enzyme structures, because collectively they illuminated catalytic mechanism (in their case, by the Ser-His-Asp "catalytic triad"), the basis of differing substrate specificities, and the activation mechanism by which a controlled enzymatic cleavage buries the new chain end to properly rearrange the active site. [ 16 ] The early crystal structures included chymotrypsin (PDB file 2CHA), [ 17 ] chymotrypsinogen (PDB file 1CHG), [ 18 ] trypsin (PDB file 1PTN), [ 19 ] and elastase (PDB file 1EST). [ 20 ] They also were the first protein structures that showed two near-identical domains, presumably related by gene duplication . One reason for their wide use as textbook and classroom examples was the insertion-code numbering system, which made Ser195 and His57 consistent and memorable despite the protein-specific sequence differences. [ citation needed ]
1968 – Papain
1969 – Carboxypeptidase A is a zinc metalloprotease . Its crystal structure (PDB file 1CPA) [ 21 ] showed the first parallel beta structure: a large, twisted, central sheet of 8 strands with the active-site Zn located at the C-terminal end of the middle strands and the sheet flanked on both sides with alpha helices. It is an exopeptidase that cleaves peptides or proteins from the carboxy-terminal end rather than internal to the sequence. Later a small protein inhibitor of carboxypeptidase was solved (PDB file 4CPA) [ 22 ] that mechanically stops the catalysis by presenting its C-terminal end just sticking out from between a ring of disulfide bonds with tight structure behind it, preventing the enzyme from sucking in the chain past the first residue.
1969 – Subtilisin (PDB file 1sbt [ 23 ] ) was a second type of serine protease with a near-identical active site to the trypsin family of enzymes, but with a completely different overall fold. This gave the first view of convergent evolution at the atomic level. Later, an intensive mutational study on subtilisin documented the effects of all 19 other amino acids at each individual position. [ 24 ]
1970 – Lactate dehydrogenase
1970 – Basic pancreatic trypsin inhibitor , or BPTI (PDB file 2pti [ 25 ] ), is a small, very stable protein that has been a highly productive model system for study of super-tight binding, disulfide bond (SS) formation, protein folding , molecular stability by amino-acid mutations or hydrogen-deuterium exchange, and fast local dynamics by NMR . Biologically, BPTI binds and inhibits trypsin while stored in the pancreas , allowing activation of protein digestion only after trypsin is released into the stomach.
1970 – Rubredoxin (PDB file 2rxn [ 26 ] ) was the first redox structure solved, a minimalist protein with the iron bound by 4 Cys sidechains from 2 loops at the top of β hairpins. It diffracted to 1.2Å, enabling the first reciprocal-space refinement of a protein (4,5rxn [ 27 ] ). (NB: note that 4rxn was done without geometry restraints.) Archaeal rubredoxins account for many of the highest-resolution small structures in the PDB.
1971 – Insulin (PDB file 1INS) [ 28 ] is a hormone central to the metabolism of sugar and fat storage, and important in human diseases such as obesity and diabetes . It is biophysically notable for its Zn binding, its equilibrium between monomer, dimer, and hexamer states, its ability to form crystals in vivo, and its synthesis as a longer "pro" form which is then cleaved to fold up as the active 2-chain, SS-linked monomer. Insulin was a success of NASA 's crystal-growth program on the Space Shuttle , producing bulk preparations of very uniform tiny crystals for controlled dosage.
1971 – Staphylococcal nuclease
1971 – Cytochrome C
1974 – T4 phage lysozyme
1974 – Immunoglobulins
1975 – Cu,Zn Superoxide dismutase
1976 – Transfer RNA
1976 – Triose phosphate isomerase | https://en.wikipedia.org/wiki/List_of_biophysically_important_macromolecular_crystal_structures |
This is a list of works classified as biopunk , a subgenre of science fiction and derivative of the cyberpunk movement. Some works may only be centered around biotechnologies and not fit a more constrained definition of biopunk which may include additional cyberpunk or postcyberpunk elements. | https://en.wikipedia.org/wiki/List_of_biopunk_works |
This list of black holes (and stars considered probable candidates) is organized by mass (including black holes of undetermined mass); some items in this list are galaxies or star clusters that are believed to be organized around a black hole. Messier and New General Catalogue designations are given where possible.
As of February 2019 [update] , 10 mergers of binary black holes have been observed. In each case two black holes merged to a larger black hole. In addition, one neutron star merger has been observed ( GW170817 ), forming a black hole. In addition, over 30 alerts have been issued since April 2019, of black hole merger candidates.
In addition, the signal of several binary black holes merging into a single black hole and in so doing producing gravitational waves have been observed by the LIGO instrument. These are listed above in the section Black holes detected by gravitational wave signals .
As of 2014, there are 5 triple black hole systems known. [ 25 ] | https://en.wikipedia.org/wiki/List_of_black_holes |
There are several psychological and physiological effects that cause blindness to some visual stimulus . | https://en.wikipedia.org/wiki/List_of_blindness_effects |
This is a list of blue plaques erected by the Royal Society of Chemistry .
The Chemical Landmark Scheme (CLS) is a Royal Society of Chemistry initiative recognising sites where the chemical sciences have made a significant contribution to health, wealth, or quality of life. The blue plaques are publicly visible, and are intended to give everyone an insight into chemistry's relevance to everyday lives. [ 1 ] CLS plaques for the first few years of the scheme (begun in 2001) were rectangular, black lettering on a steel background, but later plaques are hexagonal, white lettering on a blue background. Round plaques bearing RSC attribution do not bear the word "landmark" and are apparently without the scheme. The scheme was suspended in mid-2018 or earlier. [ 2 ] As of mid-August 2021, the RSC promise to provide a formal nomination process for new plaques "shortly". [ 3 ]
A list of plaques awarded to date can be found below.
Recently (as of mid-August 2021) the RSC have listed plaques on their own website. [ 3 ] Currently that list omits the 2015 plaque for Robert Angus Smith below, but has the following additional plaques: four awarded later than the two 2016 plaques listed here, an extra 2006 plaque to Perkin, and a 1997 plaque relating to histamine H2-receptor antagonists. The RSC list has no inscriptions or photographs in contrast to this list, but it does have the precise date of the plaque award (whereas this list gives an approximate date of installation, normally some time after the award ceremony).
In 1957 scientists working for Beecham Research Laboratories at nearby Brockham Park discovered a chemical which they used to develop many new penicillins with unique properties for the treatment of bacterial infections. These medicines have relieved suffering and saved millions of lives worldwide.
Shell Research Ltd Milstead Laboratory of Chemical Enzymology. In recognition of the pioneering work carried out here when he was co-director of the laboratory. Cornforth led a team that revealed the detailed chemistry of how enzymes work, and explained how cholesterol builds up in the body. He was awarded the Nobel Prize in Chemistry in 1975.
Professor of Chemistry. Attended this school 1837–1839. Discovered many new chemical compounds, made important contributions to chemical theory, and improved the quality of domestic water supplies. President of the Chemical Society and the Institute of Chemistry.
Apprentice apothecary to John Bingham Borlase in this building, 1795–1798. Progressed to the Medical Pneumatic Institution, Bristol, 1798 and to the Royal Institution, London, 1801. Davy established the nature of acids, identified 9 elements and invented the miner's safety lamp.
First Chief Inspector of the Alkali Inspectorate (1864–1884) Robert Angus Smith lived and worked in Manchester for 40 years, and for much of this time his laboratory was at 20 Grosvenor Square. Following his research in Manchester on air quality, in 1859 he was the first person to use the term 'acid rain'.
To mark the 100th birthday of Daniel Eley, pioneering physical chemist. His research, much of it conducted in Nottingham, bridges chemistry, physics and biology. It includes the Eley-Rideal mechanism of gas-surface reactions, organic semiconductors , discovery of the conductivity of DNA, ortho/para hydrogen conversion and understanding the structure of aqueous solutions.
In recognition of 100 years of innovation in supplying the UK with transportation fuels and important base chemicals. Saltend has uniquely combined in one location the research, development and commercialisation of numerous new processes for the manufacture of organic acids, alcohols and their derivatives.
In recognition of the 40th anniversary of the world's first commercial autocatalysts being manufactured on this site, and the subsequent development of catalysts and filters for gasoline and diesel vehicles that have cleaned billions of tonnes of pollutants from the environment worldwide.
Led pioneering work in this building from 1956–1972 and elsewhere in Oxford on the structures of antibiotics, vitamins and proteins including penicillin, vitamin B12 and insulin, using X-ray diffraction techniques for which she received the Nobel Prize in Chemistry in 1964
In recognition of the work during the 1980s by The Boots Company PLC on the development of ibuprofen which resulted in its move from prescription only status to over the counter sale, therefore expanding its use to millions of people worldwide
In recognition of the pioneering research work, here on Pennyfood Street, by Dr Stewart Adams and Dr John Nicholson in the Research Department of Boots which led to the discovery of ibuprofen used by millions worldwide for the relief of pain.
University of Southampton Chemistry. On this site in 1973, Martin Fleischmann, Patrick J. Hendra and A. James McQuillan recorded the first surface enhanced Raman spectra (SERS) leading to the development of a highly sensitive surface spectroscopic technique that is now used worldwide.
For his contribution to fireworks research, development, professional displays and for services to the pyrotechnic industry for over 50 years
1985–2002 Chairman, Centre for Photomolecular Sciences and Visiting Professor, Imperial College. 1967 Nobel Laureate for the study of fast reactions by flash photolysis.
Glucose Sensor. In this laboratory on 20 July 1982, Allen Hill , Tony Cass and Graham Davis made the crucial discovery which led to the development of a unique electronic blood glucose sensor now used by millions of diabetics worldwide.
This plaque, at the home of the Royal Society of Chemistry's publishing operations, commemorates the 170th anniversary of the society's scientific publishing, which has made a profound contribution to the advancement of the chemical sciences.
In recognition of the outstanding scientific contribution made by Charles Suckling and others, close to this site in 1951, in the synthesis and subsequent commercial development of halothane , the world's first synthetic inhalation anaesthetic .
On the occasion of the 100th anniversary of the discovery of the atomic nucleus by Ernest Rutherford, a Nobel Laureate in Chemistry and pioneer in nuclear physics, at the University of Manchester. [NB This is presumed to be the inscription on the RSC plaque, but the photograph in this entry is of a different plaque of unknown date with a different legend, donated by the Council of the City of Manchester. Research on these plaques is in progress, but hampered by Covid-19 restrictions.]
In recognition of the outstanding scientific contribution to the home and personal care industry made by Unilever Port Sunlight's laboratory since 1911. 100 years on, the people on site continue to deliver innovative products to enhance the lives of billions of consumers around the world.
Inorganic Chemistry Laboratory. Where in 1980, John B. Goodenough with Koichi Mizushima , Philip C. Jones and Philip J. Wiseman identified the cathode material that enabled development of the rechargeable lithium-ion battery. This breakthrough ushered in the age of portable electronic devices.
In recognition of the significant and enduring contribution made by Pfizer Scientists to health and quality of life through the discovery, development and manufacture of novel medicines for human and animal use. Sandwich Research laboratories established 1957.
In recognition of the pioneering research and manufacturing work carried out at the May & Baker (sanofi-aventis) Dagenham site in a wide range of chemical and pharmaceutical fields since 1934. These products continue to benefit patients and their quality of life around the world.
This plaque is in recognition of the pioneering work in the nutrition science carried out by Dr Elsie Widdowson (1906–2000). Her research provided a foundation for the work which continues in this laboratory today to improve the health of the population.
In recognition of the pioneering research and development work performed by scientists at Harwell since 1946. Their work has provided fundamental support in the development of nuclear power in the UK and a greater understanding of the chemistry of the actinide elements.
[ 24 ]
Chemist, physicist and inventor of the incandescent light bulb which he first demonstrated at a public lecture here on 3 February 1879. Nearby Mosley Street was the first street in the world to be lit by such electric bulbs.
During the period 1930–1970 Professor Sir Christopher Ingold pioneered our understanding of the electronic basis of structure, mechanism and reactivity in organic chemistry, which is fundamental to modern-day chemistry.
In recognition of the pioneering work carried out by chemists at the Alderley Park site since 1957 which has led to the discovery of therapeutic medicines, including beta-blockers and cancer therapies, that continue to provide benefits for patients throughout the world.
Founding father of Epidemiology . In 1854 his research linked deaths to the water pump near this site and thus determined that cholera is a water borne disease.
Chemistry Department University College London During the period 1930–1970 Professor Sir Christopher Ingold pioneered our understanding of the electronic basis of structure, mechanism and reactivity in organic chemistry, which is fundamental to modern-day chemistry.
This plaque is in recognition of the pioneering work carried out by scientists on this site since 1928. Research at Jealott's Hill has led to global developments in agriculture which have helped feed people and improve their quality of life.
Clarendon Laboratory where H.G.J. Moseley (1887–1915) completed his pioneering studies on the frequencies of X-rays emitted from the elements. His work established the concept of atomic number and helped reveal the structure of the atom. He predicted several new elements and laid the ground for a major tool in chemical analysis. (Plaque as shown in photograph deteriorated further - note bulging of paint - and was replaced in 2019 with a new plaque identical in inscription but with the current RSC logo as shown for instance in photographs on plaques dated 2015.)
1778–1793: Teacher (Eaglesfield, Pardshaw, Kendal) 1793–1844: Scientist and Educator (Manchester) 1817–1844: President, Manchester Lit & Phil Soc Laws of Partial Pressures and Multiple Proportions, recognised Colour Blindness and revolutionised Chemistry through his Atomic Theory
1938–1942 Student, 1957–1978 Professor, Imperial College 1969 Nobel Laureate for new concept of organic conformational analysis Erected in the Centenary Year of Imperial College London
1939–1943 Student, 1956–1996 Professor, Imperial College 1973 Nobel Laureate for pioneering studies on organometallic compounds Erected in the Centenary Year of Imperial College London
discovered mauveine, the world's first synthetic dyestuff, in 1856. He and his brother Thomas produced mauveine from a factory on this site in 1857, and later alizarin, thus laying the foundations of the organic chemicals industry. This replaces a centenary plaque unveiled by Sir R Robinson in 1957.
This plaque recognises Hexagon Site as a Chemical Landmark. Since 1786, this site has been at the heart of dyestuffs development and production in the UK.
Research in the Department of Chemistry at Cambridge over more than 50 years has established the structures and many principles of the synthesis of molecules that control the processes of life. Notably, Lord Alexander Todd FRS and his co-workers invented the chemical synthesis of nucleotides which led to the elucidation of the chemical structure of DNA.
Research in the Department of Chemistry at Hull over more than 50 years has established many principles of the design, synthesis and properties of liquid crystals for applications in display devices. Notably, Professor George Gray FRS, CBE and his co-workers invented the cyanobiphenyl class of materials, which were key to developing the first successful liquid crystal display devices.
Between 1894 and 1910, in a laboratory near this site, William Ramsay discovered and characterised the noble gases, completing the structure of the Periodic Table of Elements .
This plaque commemorates the discovery of polyethylene (better known as polythene) by R O Gibson and E W Fawcett on 27 March 1933 working in the former ICI research laboratory close to this site.
This laboratory was a major centre for Organic Chemistry from 1916–2003. It had four Heads in that time, the Waynflete Professors W H Perkin Jnr, Sir Robert Robinson OM, Sir Ewart Jones, and Sir Jack Baldwin. Sir Robert was awarded the Nobel Prize in 1947 for work done here on natural products.
Commemorating the pioneering work into the development of silicone polymers conducted by Professor Frederic S. Kipping , FRS, first Sir Jesse Boot Professor of Chemistry, at the University College laboratories in Shakespeare Street, Nottingham (1897–1928), and the Trent Building laboratories, University Park (1928–1936). His research formed the basis for the worldwide development of the synthetic rubber and silicone-based lubricant industries.
Near this site, between 1912 and 1914, Sir William H. Bragg and his son Sir W. Lawrence Bragg carried out research that led to the Nobel Prize in Physics in 1915. Their work formed the basis of crystal structure determination by X-ray diffraction which has made an outstanding contribution to chemical science.
The College was modelled on Liebig 's Laboratory at Giessen, Germany by AW Hofmann. Here, Hofmann inspired the young to do great things in chemistry, and relate them to both academic and everyday life.
Near this site Rosalind Franklin , Maurice Wilkins , Raymond Gosling , Alexander Stokes and Herbert Wilson performed experiments that led to the discover of the structure of DNA . This work revolutionised our understanding of the chemistry behind life itself.
In 1984 the principles behind DNA fingerprinting were discovered in this building by Professor Sir Alec Jeffreys and his research group.
For over 300 years explosives and propellants were developed and produced on this site. Work performed here has been influential in the development of the Bouncing Bomb , Kevlar and Ejector Seat technology.
Close to this site, in the Torridon Laboratories of the Wool Industries Research Association between 1940 and 1943, Dr Archer John Porter Martin and Dr Richard Laurence Millington Synge developed the technique of partition chromatography . Originally developed for the separation of amino acids from wool proteins , the technique became the basis for future widespread chromatographic analysis in research and development in many branches of chemistry. Drs Martin and Synge were jointly awarded the Nobel Prize for Chemistry in 1952 for this research.
Pioneering work has been carried out in these laboratories since 1970 on the chemistry of Platinum Group Metals for the development of car exhaust catalysts and the design of platinum anti-cancer drugs. Exhaust catalysts are fitted to most modern vehicles and make a global contribution to air quality. Platinum-based drugs play a major role in cancer therapy.
1846 Professor of Chemistry at the Manchester Royal Institution (City Art Gallery) 1850 F C Calvert and Co near this site 1857 First commercial production of phenol, carbolic acid, used as a disinfectant in soaps and powders and for making dyes
Born in Glasgow and Professor of Chemistry at Anderson's University (now University of Strathclyde) from 1830–1837. His famous contributions to Science were Graham's Law of Diffusion and his pioneering work on dialysis. He founded the Chemical Society of London in 1841, and became Master of the Mint. He is commemorated by this building and by a statue in George Square.
In recognition of his outstanding contribution, started on a site close to here in Birniehill Bathgate, where in c. 1850 he processed torbanite ('cannel coal') to create the first commercial production of paraffin oil in the world, leading to the major shale oil industry in West Lothian
Student 1744–1752 Lecturer in Chemistry 1756–1766 Professor of Medicine 1757–1766 Discoverer of Latent Heat, at the Old College, High Street
Graduate of Medicine 1754 Professor of Chemistry 1766–1799 Discovered the Properties of Fixed Air (Carbon Dioxide) Promoter of the Scottish Chemical Industry
Close to this site, in 1869, Andrews discovered the 'critical temperature' for the liquefaction of carbon dioxide, the basis of cryogenics and of low temperature chemistry and physics
Professor Edward (Ted) D Hughes FRS, who conducted ground breaking work on kinetics and mechanisms in organic chemistry 1943–48, played a prominent role in the 125 year history (1884–2009) of Chemistry at Bangor. Gwnaeth yr Athro Edward (Ted) D Hughes FRS waith arloesol ar gineteg a mecanwaith ym maes cemeg organig rhwng 1943 a 1948, gan chwarae rhan amiwg yn hanes cemeg ym Mangor (1884–2009)
Recognising his pioneering work at Ghent University (1858–1867) on structural and organic aromatic chemistry
In tribute to the Institut de France for honouring British Chemist Sir Humphry Davy in 1808 and encouraging the international exchange of scientific knowledge.
Sir Edward Frankland PhD FRS Professor of Chemistry 1851–1857 Organometallic compounds. Bonding and Valency. Water Analysis First President of the Institute of Chemistry.
Sir Henry Enfield Rosecoe BA PhD FRS Professor of Chemistry 1857–1886 Vanadium. Photochemistry. Spectroscopy. First President of the Society of Chemical Industry Active in the transfer of Owens College from this building to Oxford Road in 1873 and in the foundation of the Victory University in 1880
In 1928, at St. Mary's Hospital, London , Alexander Fleming discovered penicillin . This discovery led to the introduction of antibiotics that greatly reduced the number of deaths from infection. Howard W. Florey , at the University of Oxford working with Ernst B. Chain , Norman G. Heatley and Edward P. Abraham , successfully took penicillin from the laboratory to the clinic as a medical treatment in 1941. The large-scale development of penicillin was undertaken in the United States of America during the 1939–1945 World War, led by scientists and engineers at the Northern Regional Research Laboratory of the US Department of Agriculture , Abbott Laboratories, Lederle Laboratories, Merck & Co., Inc., Chas. Pfizer & Co. Inc., and E.R. Squibb & Sons. The discovery and development of penicillin was a milestone in twentieth century pharmaceutical chemistry.
On this site in the former New Meeting House Joseph Priestley LLD FRS scholar, scientist, theologian and discoverer of oxygen ministered to his congregation from 1870 to 1791
John Dalton 1766–1844 taught natural philosophy and mathematics at the Academy on this site 1793–1800. His Atomic Theory was first presented on 21 October 1803 to the Manchester Literary and Philosophical Society of which he was President 1816–1844
Download coordinates as: | https://en.wikipedia.org/wiki/List_of_blue_plaques_erected_by_the_Royal_Society_of_Chemistry |
This is a list of bridges and overpasses whose low clearance causes a notable amount of accidents, also known as bridge strikes . Simply being struck by a vehicle is not criteria for inclusion on this list. To be included, the bridge should have a notable history of strikes.
Many countries establish minimum standards for the structure gauge of bridges. For example, the United States requires a height of 14 feet (4.27 m) for highway bridges. [ 1 ] Some vehicle standards are made to conform to these expectations. In much of the United States, the maximum height of a semi truck , in the absence of an approved overheight permit, is 13 feet, 6 inches (4.12 m). [ 2 ] Some bridges were built before the adoption of these standards, and are undersized. Accidents involving these bridges have spurred mitigation efforts, such as installing sensors and signs that warn drivers. [ 3 ] These efforts do not entirely eliminate strikes, prompting some efforts to increase the clearance height. [ 4 ]
Viral videos of bridge strikes have generated substantial public interest. [ 5 ] [ 6 ] One of the most famous examples of this is the Norfolk Southern–Gregson Street Overpass , also known as the "11foot8" bridge, which was popularized by a YouTube channel. [ 7 ]
The bridges are listed in no particular order.
Before 2019: 3.56 m (11 ft 8 in) | https://en.wikipedia.org/wiki/List_of_bridges_known_for_strikes |
This page lists notable software build automation tools and systems .
These tools sequence build operations – often based on dependencies – sometimes running tasks in parallel.
Called meta-build tools, these generate configuration files for other build tools such as those listed above.
Continuous integration systems automate build operations at a relatively high level via features including: scheduling and triggering builds, storing build log and output files and integrating with version control systems. | https://en.wikipedia.org/wiki/List_of_build_automation_software |
This is a list of caffeinated alcoholic drinks with at least 9 mg caffeine — a 2005 clinical trial showed psychoactive effects in caffeine doses as low as 9 mg. [ 1 ] | https://en.wikipedia.org/wiki/List_of_caffeinated_alcoholic_drinks |
This is a list of calculus topics .
See also list of numerical analysis topics
For further developments: see list of real analysis topics , list of complex analysis topics , list of multivariable calculus topics . | https://en.wikipedia.org/wiki/List_of_calculus_topics |
This is a list of capsaicinoids , a class of compound found in members of the capsicum family . They are the chemical responsible for making chili peppers hot . The heat intensity of capsaicinoids is measured in Scoville heat units (SCU) by the Scoville heat scale . [ 1 ] | https://en.wikipedia.org/wiki/List_of_capsaicinoids |
Carboxylic acids are organic acids characterized by a carboxyl (-COOH) functional group. The naming of these compounds is governed by IUPAC nomenclature , which ensures systematic and consistent naming of chemicals. Numerous organic compounds have other common names, often originating in historical source material thereof. The systematic IUPAC name is not always the preferred IUPAC name , for example, lactic acid is a common, and also the preferred, name for what systematic rules call 2-hydroxypropanoic acid.
This list is ordered by the number of carbon atoms in a carboxylic acid.
methylbutanoic acid | https://en.wikipedia.org/wiki/List_of_carboxylic_acids |
The following is a list of centaurs , a group of non-resonant small Solar System bodies whose orbit around the Sun lie typically between the orbits of Jupiter and Neptune (5 to 30 AU ). Centaurs are minor planets with characteristics of comets , and often classified as such. The dynamical group is formed due to Neptune's eroding effect on the Kuiper belt by means of gravitational scattering, sending objects inward to become centaurs, or outward to become scattered-disc objects , or removing them from the Solar System entirely. Centaurs themselves have unstable orbits with short lifetimes, transitioning from the inactive population of Kuiper belt objects to the active group of Jupiter-family comets within a few million years. [ 1 ] [ 2 ]
The list of centaurs is compiled from MPC's MPCORB data file [ 3 ] based on criteria defined by the JPL-SBDB , [ a ] and completed with objects from the List of Known Trans-Neptunian Objects [ 4 ] and The Deep Ecliptic Survey Object Classifications . [ 5 ] by William Johnston and Marc Buie , respectively. As of April 2022 [update] , this table contains 928 objects . A dedicated column for each of these sources inidcates whether an object is considered to be a centaur ( ✓ ) or not ( ✗ ). [ b ] The table highlights red and grey centaurs with a distinct background color (see legend) . [ 2 ] [ c ]
Grey centaur (52 objs.) Red centaur (32 objs.) Centaur w/o color indices (439 objs.) Unlikely centaurs are greyed-out (405 objs.) [ d ]
Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Local Sheet → Virgo Supercluster → Laniakea Supercluster → Local Hole → Observable universe → Universe Each arrow ( → ) may be read as "within" or "part of". | https://en.wikipedia.org/wiki/List_of_centaurs_(small_Solar_System_bodies) |
The following is a list of centroids of various two-dimensional and three-dimensional objects. The centroid of an object X {\displaystyle X} in n {\displaystyle n} - dimensional space is the intersection of all hyperplanes that divide X {\displaystyle X} into two parts of equal moment about the hyperplane. Informally, it is the " average " of all points of X {\displaystyle X} . For an object of uniform composition, or in other words, has the same density at all points, the centroid of a body is also its center of mass . In the case of two-dimensional objects shown below, the hyperplanes are simply lines.
For each two-dimensional shape below, the area and the centroid coordinates ( x ¯ , y ¯ ) {\displaystyle ({\bar {x}},{\bar {y}})} are given:
The area between the curve y = h b 2 x 2 {\displaystyle y={\frac {h}{b^{2}}}x^{2}} and the y {\displaystyle \,\!y} axis, from y = 0 {\displaystyle \,\!y=0} to y = h {\displaystyle \,\!y=h}
For each three-dimensional body below, the volume and the centroid coordinates ( x ¯ , y ¯ , z ¯ ) {\displaystyle ({\bar {x}},{\bar {y}},{\bar {z}})} are given: | https://en.wikipedia.org/wiki/List_of_centroids |
This lists the character tables for the more common molecular point groups used in the study of molecular symmetry . These tables are based on the group-theoretical treatment of the symmetry operations present in common molecules , and are useful in molecular spectroscopy and quantum chemistry . Information regarding the use of the tables, as well as more extensive lists of them, can be found in the references. [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ]
For each non-linear group, the tables give the most standard notation of the finite group isomorphic to the point group, followed by the order of the group (number of invariant symmetry operations). The finite group notation used is: Z n : cyclic group of order n , D n : dihedral group isomorphic to the symmetry group of an n –sided regular polygon, S n : symmetric group on n letters, and A n : alternating group on n letters.
The character tables then follow for all groups. The rows of the character tables correspond to the irreducible representations of the group, with their conventional names, known as Mulliken symbols, [ 6 ] in the left margin. The naming conventions are as follows:
All but the two rightmost columns correspond to the symmetry operations which are invariant in the group. In the case of sets of similar operations with the same characters for all representations, they are presented as one column, with the number of such similar operations noted in the heading.
The body of the tables contain the characters in the respective irreducible representations for each respective symmetry operation, or set of symmetry operations. The symbol i used in the body of the table denotes the imaginary unit : i 2 = −1. Used in a column heading, it denotes the operation of inversion. A superscripted uppercase "C" denotes complex conjugation .
The two rightmost columns indicate which irreducible representations describe the symmetry transformations of the three Cartesian coordinates ( x , y and z ), rotations about those three coordinates ( R x , R y and R z ), and functions of the quadratic terms of the coordinates( x 2 , y 2 , z 2 , xy , xz , and yz ).
A further column is included in some tables, such as those of Salthouse and Ware [ 7 ] For example,
The last column relates to cubic functions which may be used in applications regarding f orbitals in atoms.
These groups are characterized by a lack of a proper rotation axis, noting that a C 1 {\displaystyle C_{1}} rotation is considered the identity operation. These groups have involutional symmetry: the only nonidentity operation, if any, is its own inverse.
In the group C 1 {\displaystyle C_{1}} , all functions of the Cartesian coordinates and rotations about them transform as the A {\displaystyle A} irreducible representation.
The families of groups with these symmetries have only one rotation axis.
The cyclic groups are denoted by C n . These groups are characterized by an n -fold proper rotation axis C n . The C 1 group is covered in the nonaxial groups section.
The reflection groups are denoted by C nh . These groups are characterized by i) an n -fold proper rotation axis C n ; ii) a mirror plane σ h normal to C n . The C 1 h group is the same as the C s group in the nonaxial groups section.
The pyramidal groups are denoted by C nv . These groups are characterized by i) an n -fold proper rotation axis C n ; ii) n mirror planes σ v which contain C n . The C 1 v group is the same as the C s group in the nonaxial groups section.
The improper rotation groups are denoted by S n . These groups are characterized by an n -fold improper rotation axis S n , where n is necessarily even. The S 2 group is the same as the C i group in the nonaxial groups section. S n groups with an odd value of n are identical to C n h groups of same n and are therefore not considered here (in particular, S 1 is identical to C s ).
The S 8 table reflects the 2007 discovery of errors in older references. [ 4 ] Specifically, ( R x , R y ) transform not as E 1 but rather as E 3 .
The families of groups with these symmetries are characterized by 2-fold proper rotation axes normal to a principal rotation axis.
The dihedral groups are denoted by D n . These groups are characterized by i) an n -fold proper rotation axis C n ; ii) n 2-fold proper rotation axes C 2 normal to C n . The D 1 group is the same as the C 2 group in the cyclic groups section.
The prismatic groups are denoted by D nh . These groups are characterized by i) an n -fold proper rotation axis C n ; ii) n 2-fold proper rotation axes C 2 normal to C n ; iii) a mirror plane σ h normal to C n and containing the C 2 s. The D 1 h group is the same as the C 2 v group in the pyramidal groups section.
The D 8 h table reflects the 2007 discovery of errors in older references. [ 4 ] Specifically, symmetry operation column headers 2S 8 and 2S 8 3 were reversed in the older references.
The antiprismatic groups are denoted by D nd . These groups are characterized by i) an n -fold proper rotation axis C n ; ii) n 2-fold proper rotation axes C 2 normal to C n ; iii) n mirror planes σ d which contain C n . The D 1 d group is the same as the C 2 h group in the reflection groups section.
These symmetries are characterized by having more than one proper rotation axis of order greater than 2.
These polyhedral groups are characterized by not having a C 5 proper rotation axis.
These polyhedral groups are characterized by having a C 5 proper rotation axis.
These groups are characterized by having a proper rotation axis C ∞ around which the symmetry is invariant to any rotation. | https://en.wikipedia.org/wiki/List_of_character_tables_for_chemically_important_3D_point_groups |
A list of chemical analysis methods with acronyms. | https://en.wikipedia.org/wiki/List_of_chemical_analysis_methods |
Chemical arms control is the attempt to limit the use or possession of chemical weapons through arms control agreements. These agreements are often motivated by the common belief "that these weapons ...are abominable", [ 1 ] and by a general agreement that chemical weapons do "not accord with the feelings and principles of civilized warfare ." [ 2 ]
The first chemical arms control agreement was the Strasbourg Agreement of 1675 between France and the Holy Roman Empire . This bilateral pact prohibited the use of poisoned bullets in any war between the two states. [ 3 ] In the several centuries after that agreement, as chemistry advanced, states developed more sophisticated chemical weapons, and the primary concern in arms control shifted from poison bullets to poison gases. Thus, in the Hague Convention of 1899 , a large group of states agreed "to abstain from the use of projectiles the sole objective of which is the diffusion of asphyxiating or deleterious gases". [ 4 ] The 1907 Hague Convention and other early attempts at chemical arms control were also significant in restricting the use of chemical weapons in warfare.
World War I broke out in Europe less than 20 years after the signing of the Hague Conventions. During that conflict, chemical weapons were used extensively by all sides in what still remains the largest case of chemical warfare . [ 5 ] The use of chemical weapons in warfare was a war crime as such use was in direct violation of the 1899 Hague Declaration Concerning Asphyxiating Gases and the 1907 Hague Convention on Land Warfare , which prohibited the use of "poison or poisoned weapons" in warfare. [ 6 ] [ 7 ] After World War I, arms control agreements in general, and chemical arms control agreements in particular, gained renewed support. After seeing the gas attacks of the war, the general public overwhelmingly supported provisions that strongly regulated chemical weapons. In one survey of Americans, 367,000 favored banning chemical warfare while 19 supported its continuation in the future. This public opinion stimulated increased efforts for a ban on chemical weapons. [ 8 ] These efforts led to several agreements in the years before World War II , including the Geneva Protocol . [ 9 ]
World War II was seen as a significant success for chemical arms control as none of the belligerents made significant use of chemical weapons. [ 10 ] In the immediate aftermath of the war, arms control efforts focused primarily on nuclear weapons given their immense destructive power, and chemical disarmament was not a priority. [ 11 ] Nonetheless, chemical warfare began to expand again with gas attacks during the Yemeni Civil War , [ 12 ] and allegations of use during the Korean War . [ 13 ] [ 14 ] [ 15 ] Along with the substantial use of chemical weapons in the Iran–Iraq War , these incidents led to a renewed interest in chemical disarmament and increased the push towards disarmament, [ 16 ] finally culminating in the 1993 Chemical Weapons Convention , a full-scale ban on the use, production and stockpiling of weapons, which took force in 1997. [ 17 ] | https://en.wikipedia.org/wiki/List_of_chemical_arms_control_agreements |
Chemical classification systems attempt to classify elements or compounds according to certain chemical functional or structural properties. Whereas the structural properties are largely intrinsic , functional properties and the derived classifications depend to a certain degree on the type of chemical interaction partners on which the function is exerted. Sometimes other criteria like purely physical ones (e.g. molecular weight ) or – on the other hand – functional properties above the chemical level are also used for building chemical taxonomies .
Some systems mix the various levels, resulting in hierarchies where the domains are slightly confused, for example having structural and functional aspects end up on the same level. Whereas chemical function is closely dependent on chemical structure, the situation becomes more involved when e.g. pharmacological function is integrated, because the QSAR can usually not be directly computed from structural qualities. | https://en.wikipedia.org/wiki/List_of_chemical_classifications |
There are more than 1,000 chemical compounds in coffee , [ 1 ] and their molecular and physiological effects are areas of active research in food chemistry .
There are a large number of ways to organize coffee compounds. The major texts in the area variously sort by effects on flavor, physiology, pre- and post-roasting effects, growing and processing effects, botanical variety differences, country of origin differences, and many others. Interactions between chemical compounds also is a frequent area of taxonomy , as are the major organic chemistry categories ( protein , carbohydrate , lipid , etc.) that are relevant to the field. In the field of aroma and flavor alone, Flament gives a list of 300 contributing chemicals in green beans, and over 850 after roasting. He lists 16 major categories to cover those compounds related to aroma and flavor. [ 2 ]
The chemical complexity of coffee is emerging, especially due to observed physiological effects which cannot be related only to the presence of caffeine . Moreover, coffee contains an exceptionally substantial amount of antioxidants such as chlorogenic acids , hydroxycinnamic acids , caffeine and Maillard reaction products, such as melanoidins . [ 3 ] Chemical groups, such as alkaloids and caffeoylquinic acids , are common insecticides ; their effects on coffee quality and flavor have been investigated in most studies. [ 4 ] Although health effects are certainly a valid taxonomy category, less than 30 of the over 1,000 compounds have been subjected to juried, health-related research (e.g. official potential carcinogen classification — see furans , for example), so health categorization has been avoided.
On the other hand, physiological effects are well documented in some (e.g. stimulant effects of caffeine), and those are listed where they are relevant and well-documented. Internet claims for individual chemicals, or compound synergies, such as preventing dental cavities (speculative but unproven effect of the alkaloid trigonelline with in vitro bacterial attachment research, but missing in vivo research on any health effects), preventing kidney stones , or negative effects, also have been avoided.
Chemicals found in coffee can be categorized in the following groups:
Quinic acid , 3,5-Di-caffeoylquinic acid
Caffeine , Putrescine , Theophylline , Trigonelline
Quinic acid , Acetoin
3,5-Di-caffeoylquinic acid
Acetoin
Dimethyl disulfide
3,5-Di-caffeoylquinic acid | https://en.wikipedia.org/wiki/List_of_chemical_compounds_in_coffee |
Chemical nomenclature , replete as it is with compounds with very complex names, is a repository for some names that may be considered unusual. A browse through the Physical Constants of Organic Compounds in the CRC Handbook of Chemistry and Physics (a fundamental resource) will reveal not just the whimsical work of chemists , but the sometimes peculiar compound names that occur as the consequence of simple juxtaposition . Some names derive legitimately from their chemical makeup, from the geographic region where they may be found, the plant or animal species from which they are isolated or the name of the discoverer.
Some are given intentionally unusual trivial names based on their structure, a notable property or at the whim of those who first isolate them. However, many trivial names predate formal naming conventions. Trivial names can also be ambiguous or carry different meanings in different industries, geographic regions and languages.
Godly noted that "Trivial names having the status of INN or ISO are carefully tailor-made for their field of use and are internationally accepted". [ 1 ] In his preface to Chemical Nomenclature , Thurlow wrote that "Chemical names do not have to be deadly serious". [ 2 ] A website in existence since 1997 [ 3 ] and maintained at the University of Bristol lists a selection of "molecules with silly or unusual names" strictly for entertainment. These so-called silly or funny trivial names (depending on culture) can also serve an educational purpose. In an article in the Journal of Chemical Education , Dennis Ryan argues that students of organic nomenclature (considered a "dry and boring" subject) may actually take an interest in it when tasked with the job of converting funny-sounding chemical trivial names to their proper systematic names. [ 4 ]
The collection listed below presents a sample of trivial names and gives an idea how chemists are inspired when they coin a brand new name for a chemical compound outside of systematic naming. It also includes some examples of systematic names and acronyms that accidentally resemble English words.
Glenn Seaborg told his students that he proposed the chemical symbol Pu (from P U ) instead of the conventional "Pl" for plutonium as a joke, only to find it officially adopted. [ 5 ] Unununium (Uuu) was the former temporary name of the chemical element number 111, a synthetic transuranium element . This element was named roentgenium (Rg) in November 2004.
There are no chemical or practical uses for the NanoKid molecule or any of its known derivatives. However, James Tour has turned the NanoKid into a lifelike character to educate children in the sciences. It was found that 82% of students found that NanoKids made learning science more interesting and led to a 10–59% increase in understanding of the material presented, lending this otherwise purposeless thing some small value. [ 10 ]
A mineral named after the US amateur mineralogist Wilfred R. Welsh. Its formula is Ca 2 SbMg 4 FeBe 2 Si 4 O 20 . | https://en.wikipedia.org/wiki/List_of_chemical_compounds_with_unusual_names |
This is a list of websites that contain lists of chemicals, or databases of chemical information. There is further detail on the content of these and other resources in a Wikibook of information sources .
MetaCyc
metabolic pathways
20412 targets
Organic Compounds
Toxic Exposome Database
DOT + others | https://en.wikipedia.org/wiki/List_of_chemical_databases |
This article lists the etymology of chemical elements of the periodic table .
Throughout the history of chemistry , many chemical elements have been discovered. In the 19th century, Dmitri Mendeleev formulated the periodic table , a table of elements which describes their structure. Because elements have been discovered at various times and places, from antiquity through the present day, their names have derived from several languages and cultures.
41 of the 118 known elements have names associated with, or specifically named for, places around the world or among astronomical objects. 32 of these have names tied to the places on Earth, and the other nine are named after to Solar System objects: helium and selenium for the Sun and Moon ; mercury (indirectly), tellurium , uranium and neptunium for the planets Mercury , Earth , Uranus and Neptune ; plutonium and cerium for the dwarf planets Pluto and Ceres , both considered planets when the elements were named; and palladium for the asteroid Pallas . [ 1 ]
Nineteen elements are connected with the names of twenty people (as curium honours both Marie and Pierre Curie ). Of these, only gadolinium and samarium occur in nature; the rest are synthetic . Fifteen elements were named after scientists; four other have indirect connection to the names of non-scientists. [ 1 ] Only Glenn T. Seaborg and Yuri Oganessian were honored during their lifetime by having elements named after them, and Oganessian is the only one still living. Elements named after four non-scientists in this table were actually named for a place or thing which in turn had been named for these people. Samarium was named for the mineral from which it was isolated, samarskite , which was named for Vassili Samarsky-Bykhovets . Berkelium and livermorium were named for the California cities Berkeley and Livermore , the locations of the Lawrence Berkeley and Lawrence Livermore national laboratories; the cities were named for George Berkeley and Robert Livermore . Americium was named for America, which was named for Amerigo Vespucci .
Also, mythological entities have had a significant impact on the naming of elements, directly or indirectly. Cerium , europium , helium , iridium , mercury , neptunium , niobium , palladium , plutonium , promethium , selenium , tantalum , titanium , thorium , uranium and vanadium are all connected to mythological deities.
Elements may also have been named after minerals (in which they were discovered). For example, beryllium is named after beryl .
Other element names given after people have been proposed but failed to gain official international recognition. These include columbium (Cb), hahnium (Ha), joliotium (Jl), and kurchatovium (Ku), names connected to Christopher Columbus , Otto Hahn , Irène Joliot-Curie , and Igor Kurchatov ; and also cassiopeium (Cp), a name coming from the constellation Cassiopeia and is hence indirectly connected to the mythological Cassiopeia .
For the last two decades, IUPAC has been the governing body for naming elements. IUPAC has also provided a temporary name and symbol for unknown or recently synthesized elements. | https://en.wikipedia.org/wiki/List_of_chemical_element_name_etymologies |
118 chemical elements have been identified and named officially by IUPAC . A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number , or Z ). [ 1 ]
The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding developments of modern chemistry . It is a tabular arrangement of the elements by their chemical properties that usually uses abbreviated chemical symbols in place of full element names, but the linear list format presented here is also useful. Like the periodic table, the list below organizes the elements by the number of protons in their atoms; it can also be organized by other properties, such as atomic weight , density , and electronegativity . For more detailed information about the origins of element names, see List of chemical element name etymologies . | https://en.wikipedia.org/wiki/List_of_chemical_elements |
This list of chemical elements named after people includes elements named for people both directly and indirectly. Of the 118 elements, 19 are connected with the names of 20 people. 15 elements were named to honor 16 scientists (as curium honours both Marie and Pierre Curie ). Four others have indirect connection to the names of non-scientists. [ 1 ] Only gadolinium and samarium occur in nature; the rest are man-made .
These 19 elements are connected to the names of people. Seaborg and Oganessian were the only living persons honored by having elements named after them; Oganessian is the only one still alive. Names were proposed to honor Einstein and Fermi while they were still alive, but they had both died by the time those names became official. [ 2 ]
The four elements associated with non-scientists were not named in their honor but named for something else bearing their name: samarium for the mineral samarskite from which it was isolated; and americium , berkelium and livermorium after places named for them. The cities of Berkeley, California and Livermore, California are the locations of the University of California Radiation Laboratory and Lawrence Livermore National Laboratory , respectively.
Other element names connected with people (real or mythological) have been proposed but failed to gain official international recognition. The following such names received past significant use among scientists:
Names had also been suggested (but not used) to honour Henri Becquerel ( becquerelium ) and Paul Langevin ( langevinium ). [ 4 ] [ 5 ] George Gamow , Lev Landau , and Vitalii Goldanski [ ru ] (who was alive at the time) were suggested for consideration for honoring with elements during the Transfermium Wars , but were not actually proposed. [ 2 ]
(See the article on element naming controversies and List of chemical elements named after places .)
Also, mythological entities have had a significant impact on the naming of elements. Helium , titanium , selenium , palladium , promethium , cerium , europium , tantalum , mercury , thorium , uranium , neptunium and plutonium are all given names connected to mythological characters. With some, that connection is indirect:
Titanium is unique in that it refers to a group of deities rather than any particular individual. So Helios, Selene, Pallas, and Prometheus actually have two elements named in their honor.
And for elements given a name connected with a group, there is also xenon , named for the Greek word ξένον (xenon), neuter singular form of ξένος (xenos), meaning 'foreign(er)', 'strange(r)', or 'guest'. [ 6 ] [ 7 ] Its discoverer William Ramsay intended this name to be an indication of the qualities of this element in analogy to the generic group of people.
Gallium was discovered by French scientist Paul-Émile Lecoq de Boisbaudran , who named it in honor of France ("Gallia" in Latin); allegations were later made that he had also named it for himself, as "gallus" is Latin for " le coq ", but he denied that this had been his intention. [ 8 ] | https://en.wikipedia.org/wiki/List_of_chemical_elements_named_after_people |
This is the list of chemical engineering societies in the world. They are sorted by continent and alphabetically. They include national or international ones, but not student societies or those otherwise restricted to a particular university or institution. | https://en.wikipedia.org/wiki/List_of_chemical_engineering_societies |
This is a list of notable chemical engineers , people who studied or practiced chemical engineering . The main list is those who achieved status in chemical engineering or a closely related field such as management or science. At the foot of the page is a list of people with chemical engineering qualifications who are notable for other reasons, such as actors, sportspeople and authors. These are people sufficiently notable to have an article in Wikipedia. Further articles on chemical engineers would be welcome. See the talk page for suggestions of people who should be added to the encyclopedia (and then to this list).
Bohr Institute University College London George Washington University Manhattan Project University of Chicago UC Davis UC Berkeley Lawrence Livermore Hoover Institution | https://en.wikipedia.org/wiki/List_of_chemical_engineers |
This is a list of software used to simulate the material and energy balances of chemical process plants. Applications for this include design studies, engineering studies, design audits, debottlenecking studies, control system check-out, process simulation , dynamic simulation , operator training simulators , pipeline management systems, production management systems, digital twins .
[30]
(former SimCentral) | https://en.wikipedia.org/wiki/List_of_chemical_process_simulators |
A chemical weapon agent (CWA), or chemical warfare agent, is a chemical substance whose toxic properties are meant to kill, injure or incapacitate human beings . About 70 different chemicals have been used or stockpiled as chemical weapon agents during the 20th century, although the Organisation for the Prohibition of Chemical Weapons (OPCW) has an online database listing 35,942 chemicals which may be used as weapons. [ 1 ] These agents may be in liquid, gas or solid form.
In general, chemical weapon agents are organized into several categories (according to the physiological manner in which they affect the human body). They may also be divided by tactical purpose or chemical structure. The names and number of categories may vary slightly from source to source, but, in general, the different types of chemical warfare agents are listed below.
These are substances that are not intended to kill or injure. They are often referred to as Riot Control Agents (RCAs) and may be used by civilian police forces against criminals and rioters, or in the military for training purposes. These agents also have tactical utility to force combatants out of concealed or covered positions for conventional engagement, and preventing combatants from occupying contaminated terrain or operating weapons. In general, harassing agents are sensory irritants that have fleeting concentration dependent effects that resolve within minutes after removal. Casualty effects are not anticipated to exceed 24-hours nor require medical attention.
These sensory irritants produce immediate pain to the eyes and irritate mucous membranes (aka lachrymatory agent or lachrymator ).
These sensory irritants are also termed sternators or nose irritants. They irritate the mucous membranes to produce congestion, coughing, sneezing, and eventually nausea.
These are compounds with a very strong and unpleasant smell, which produce powerfully aversive effects without the toxic effects of tear agents or vomiting agents.
These are substances that produce debilitating effects with limited probability of permanent injury or loss of life. The casualty effects typically last over 24 hours, and though medical evacuation and isolation is recommended, it is not required for complete recovery. These, together with harassing agents, are sometimes called nonlethal agents. There may be as high as 5% fatalities with the use of these agents.
These are substances that produce casualty effects through mental disturbances such as delirium or hallucination.
These substances have also been investigated as incapacitants, though they operate more through interactions outside the central nervous system.
These substances are for producing chemical casualties without regard to long-term consequences or loss of life. They cause injuries that require medical treatment.
A blister agent is a chemical compound that irritates and causes injury to the skin. These substances also attack the eyes, or any other tissue they contact.
The vesicants are substances that produce large fluid-filled blisters on the skin.
The urticants are substances that produce a painful wheal on the skin. These are sometimes termed skin necrotizers and are known as the most painful substances produced. [ according to whom? ]
These substances are metabolic poisons that interfere with the life-sustaining processes of the blood.
These substances are sometime referred to as pulmonary agent or lung irritants and cause injury to the lung-blood barrier resulting in Asphyxia .
Nerve agents are substances that disrupt the chemical communications through the nervous system. One mechanism of disruption, utilized by the G, GV, and V series of chemicals is caused by blocking the acetylcholinesterase , an enzyme that normally destroys and stops the activity of acetylcholine , a neurotransmitter . Poisoning by these nerve agents leads to an accumulation of acetylcholine at the nerve axon , producing a perpetual excited state in the nerve (e.g. constant muscle contraction). The eventual exhaustion of muscles leads to respiratory failure and death. A separate class of nerve agents are related to Tetrodotoxin, frequently abbreviated as TTX, is a potent neurotoxin with no known antidote. Tetrodotoxin blocks action potentials in nerves by binding to the voltage-gated, fast sodium channels in nerve cell membranes, essentially preventing any affected nerve cells from firing by blocking the channels used in the process.
These are high volatility nerve agents that are typically used for a nonpersistent to semipersistent effect.
These agents have a volatility between the V and G agents and are typically used for a semi-persistent to persistent effect.
These agents have low volatility and are typically used for a persistent effect or liquid contact hazard.
These agents are related to the puffer fish | https://en.wikipedia.org/wiki/List_of_chemical_warfare_agents |
Cheminformatics toolkits are notable software development kits that allow cheminformaticians to develop custom computer applications for use in virtual screening, chemical database mining, and structure-activity studies. [ 1 ] [ 2 ] Toolkits are often used for experimentation with new methodologies. Their most important functions deal with the manipulation of chemical structures and comparisons between structures. Programmatic access is provided to properties of individual bonds and atoms.
Toolkits provide the following functionality: | https://en.wikipedia.org/wiki/List_of_cheminformatics_toolkits |
This list of chemistry awards is an index to articles about notable awards for chemistry . It includes awards by the Royal Society of Chemistry , the American Chemical Society , the Society of Chemical Industry and awards by other organizations.
The Royal Society of the United Kingdom offers a number of awards for chemistry.
The American Chemical Society of the United States offers a number of awards related to chemistry.
The Society of Chemical Industry was established in 1881 by scientists, inventors and entrepreneurs. It offers a number of awards related to chemistry. | https://en.wikipedia.org/wiki/List_of_chemistry_awards |
This is a list of scientific journals in chemistry and its various subfields. For journals mainly about materials science, see List of materials science journals . | https://en.wikipedia.org/wiki/List_of_chemistry_journals |
The following is a list of chemistry societies : [ 1 ]
Lithuanian Chemical Society | https://en.wikipedia.org/wiki/List_of_chemistry_societies |
This is a list of chemists . It should include those who have been important to the development or practice of chemistry . Their research or application has made significant contributions in the area of basic or applied chemistry. | https://en.wikipedia.org/wiki/List_of_chemists |
This is a list of the 29 molecules of chlorinated propane in order of number of chlorine atoms. [ 1 ] | https://en.wikipedia.org/wiki/List_of_chlorinated_propanes |
Commercial tobacco smoke is a mixture of more than 5,000 chemicals . [ 1 ] A 2011 report in the International Journal of Environmental Research and Public Health (IJERPH) lists 65 carcinogens or possible carcinogens: "Our list of hazardous smoke components includes all nine components reported in mainstream cigarette smoke that are known human carcinogens ( IARC Group I carcinogens ), as well as all nine components that are probably carcinogenic to humans ( IARC Group 2A carcinogens ). In addition, it contains 34 of the 48 components that are possibly carcinogenic to humans ( IARC Group 2B carcinogens )." [ 1 ] | https://en.wikipedia.org/wiki/List_of_cigarette_smoke_carcinogens |
This list of circle topics includes things related to the geometric shape, either abstractly, as in idealizations studied by geometers, or concretely in physical space. It does not include metaphors like "inner circle" or "circular reasoning" in which the word does not refer literally to the geometric shape. | https://en.wikipedia.org/wiki/List_of_circle_topics |
Climate engineering geoengineering topics related to greenhouse gas remediation include: | https://en.wikipedia.org/wiki/List_of_climate_engineering_topics |
List of software for cluster management . | https://en.wikipedia.org/wiki/List_of_cluster_management_software |
The following is a list of compression formats and related codecs .
(low bit rate, optimized for speech)
Those codecs are used by many PC games which use voice chats via Microsoft DirectPlay API.
VP8, [ 68 ] VP9, [ 68 ] AV1, [ 68 ] and H.266/VVC support scalable modes by default. | https://en.wikipedia.org/wiki/List_of_codecs |
The World Geographical Scheme for Recording Plant Distributions (WGSRPD) is a biogeographical system developed by the international Biodiversity Information Standards (TDWG) organization, formerly the International Working Group on Taxonomic Databases. The system provides clear definitions and codes for recording plant distributions at four scales or levels, from "botanical continents" down to parts of large countries. Current users of the system include the International Union for Conservation of Nature (IUCN), and the Germplasm Resources Information Network (GRIN). [ 1 ] Plants of the World Online uses Kew 's data sources, [ 2 ] and hence also uses the WGSRPD for distributions.
The table is arranged in the systematic order used in the WGSRPD. The levels used in the scheme are: | https://en.wikipedia.org/wiki/List_of_codes_used_in_the_World_Geographical_Scheme_for_Recording_Plant_Distributions |
This list is divided into proprietary or free software, and open source software, with several comparison tables of different product and vendor characteristics. It also includes a section of project collaboration software, which is a standard feature in collaboration platforms .
Systems listed on a light purple background are no longer in active development.
The following are open source applications for collaboration: | https://en.wikipedia.org/wiki/List_of_collaborative_software |
This article is a list of column-oriented database management system software. | https://en.wikipedia.org/wiki/List_of_column-oriented_DBMSes |
In many countries, combat engineers are members of broader military engineering corps or branches. Examples of this include: | https://en.wikipedia.org/wiki/List_of_combat_engineering_corps |
List of combinatorial computational geometry topics enumerates the topics of computational geometry that states problems in terms of geometric objects as discrete entities and hence the methods of their solution are mostly theories and algorithms of combinatorial character.
See List of numerical computational geometry topics for another flavor of computational geometry that deals with geometric objects as continuous entities and applies methods and algorithms of nature characteristic to numerical analysis . | https://en.wikipedia.org/wiki/List_of_combinatorial_computational_geometry_topics |
This is a list of known combined sex-hormonal formulations . Brand names and developmental code names are in parentheses.
In birth control pills :
For menopausal hormone therapy and/or gynecological disorders :
In birth control pills :
In contraceptive patches :
For menopausal hormone therapy :
In contraceptive vaginal rings :
In combined injectable contraceptives :
For menopausal hormone therapy , gynecological disorders , habitual abortion , and other indications:
In combined injectable contraceptives :
For other indications: | https://en.wikipedia.org/wiki/List_of_combined_sex-hormonal_preparations |
Certain products related to computing, such as hardware , software , and smartphones , were mass-marketed and highly anticipated ahead of their launch, but are known to have failed commercially. Reasons for their failure include the products failing consumer expectations upon launch, the first round of units suffering defects, a controversy negatively affecting sales, or being the result of poor marketing, regardless of reception. In any case, these products failed to meet their companies' expectations needed to be considered successful, typically due to them failing on average to break even , resulting in the companies losing money. [ 1 ] These high-profile items tend to appear on computer- and hardware-related "worst" lists or lists of failures (e.g., "tech fails").
The CueCat is a cat-shaped barcode reader created by Dallas-based Digital Convergence Corporation amid the dot-com bubble and distributed from 2000 until the company's bankruptcy in 2001. Invented by Jovan Hutton Pulitzer (then named Jeffry Jovan Philyaw) intended to make accessing the websites of advertisers from newspapers, magazines, and catalogs easier, the device was plugged into a computer through its PS/2 port (later a USB port) and, along with regular barcodes , could read specialized barcodes on printed advertisements, which would then take the user to the target web page . The company heavily promoted the CueCat as it aimed to sell 50 million units by the end of 2001. The product's sponsors included The Coca-Cola Company , RadioShack , NBC , and Belo Corporation . [ 2 ] It also mailed hundreds of thousands to subscribers of newspapers and magazines; Forbes distributed about 830,000 units and Wired about 500,000. [ 3 ] [ 4 ]
The CueCat's concept of replacing typing in a URL with scanning barcodes for convenience was met with criticism and derision. Walt Mossberg of The Wall Street Journal lampooned the need to have a computer nearby when scanning, calling it "unnatural and ridiculous". He also found that the majority of the special barcodes did not match the printed URLs, instead linking to general web pages, for which he asserted he could have typed them in faster. [ 5 ] In addition, Digital Convergence received criticism for using the devices to send personally identifiable information of their users back to the company. The security concerns were amplified when, in late 2000, the CueCat website was subject to a breach that exposed the users' personal names and email addresses. [ 6 ] Digital Convergence ended up giving out four million units in the United States—far short of its 50 million goal—with six million left unsold, [ 2 ] and the company folded in 2001. The CueCat was ranked No. 20 on PC World ' s list of "The 25 Worst Tech Products of All Time". [ 7 ] It also landed on Time ' s list of "The 50 Worst Inventions", calling it "little more than a high-tech paperweight". [ 8 ] Despite its poor showing, the CueCat has been viewed as a precursor to QR codes , which have become ubiquitous. [ 6 ]
Itanium was a brand of 64-bit Intel microprocessors first announced in 1994 and released in 2001, [ 9 ] after long delays. [ 10 ] It was born in December 1988 as a secret Hewlett-Packard research project to succeed the company's PA-RISC instruction set architecture . [ 10 ] Intel had its own processor in development, which would have extended its own x86 architecture to 64 bits while still retaining x86 compatibility, but dropped all work on the chip's design by June 8, 1994, when it announced a collaboration with Hewlett-Packard to develop a new 64-bit architecture called IA-64 . [ 11 ]
Intel announced the Itanium in 1997 with considerable fanfare, with International Data Group initially projecting sales to reach $38 billion by 2001. [ 12 ] However, the first Itanium processor, codenamed Merced, suffered development delays, leading Silicon Graphics to cancel its first-generation Itanium system and Sun Microsystems to abandon the Itanium version of its Solaris operating system. Merced garnered a negative reception upon its May 2001 release for its sluggish performance and software incompatibility with x86-based processors. [ 10 ] Meanwhile, in 2003, Advanced Micro Devices announced the first fully x86-compatible 64-bit processor, AMD64 -based Opteron , and Intel faced a new challenger to its dominance in the office and home user markets. [ 13 ] Intel was also forced to lower its ambitions for the struggling Itanium to being only a niche product for high-end systems, or what Pat Gelsinger called "the biggest iron". Further trouble was spelled in 2005, when Microsoft canceled Windows for Itanium-based workstations and IBM and Dell dropped dropped Itanium servers, with HP being the only top server manufacturer to sell them. [ 10 ] When in 2019 Intel announced that it would accept orders up until January 30, 2020, and ship the last microprocessors by July 29, 2021, the only systems that were powered by a Itanium 9700-based chip, the last of the Itanium chips sold, were HPE Integrity Superdome computers. [ 14 ] Far short of IDG's original projections, the Itanium line of processors generated sales worth only $1.4 billion, [ 12 ] against an estimated billions invested into the project, and ultimately failed to replace the x86 architecture. [ 10 ] The Itanium was soon recognized as a failure, for which the computer industry dubbed it " Itanic ", after the ill-fated ocean liner . [ 12 ] [ 13 ]
The TI-99/4 was the first mass-marketed home computer with a 16-bit microprocessor, which in this case was the TMS9900 —the same processor used by TI-990 minicomputers . Manufactured by Texas Instruments , the TI-99/4 was born from two separate projects for a low-end video game console and a hobbyist-oriented personal computer, which were merged into one as a result of the two teams competing for the same company resources. The computer first retailed for $1,150 (equivalent to $4,982 in 2024) in 1979 and, due to the Federal Communications Commission 's strict RFI emissions regulations, shipped with a 13 in (33 cm) custom color TV monitor. [ 15 ] [ 16 ]
The TI-99/4, intended to serve both the video game and home computer markets, was received negatively. [ 15 ] The chiclet keyboard was widely criticized, which, according to Joseph Nocera of Texas Monthly , "became the symbol for everything that was wrong" with the computer. A dearth of third-party software was also noted, due to both the hurdles of writing programs imposed by the TMS9900 processor and Texas Instruments' insistence that it make a profit from third-party software. [ 17 ] The computer was referred to by The New York Times as "an embarrassing failure". [ 15 ] The high cost of the TMS9900's nonstandard packaging precluded the company from earning a profit for each machine sold, [ 15 ] and various reports estimate that only between 20,000 and 100,000 units were ever sold. [ 16 ] Two editors for Creative Computing voted the TI-99/4 as one of the world's worst computers, [ 18 ] ranked No. 6 on PC Magazine ' s list of "The 12 Biggest PC Duds Ever", [ 19 ] and PC World ranked the machine No. 6 on its list of "The 10 Worst PCs of All Time", both criticizing the chiclet keyboard and the latter magazine also citing the need to connect to the computer's own display as one of the reasons for its failure. The computer was supplanted in 1981 by an upgrade, the TI-99/4A , Texas Instruments' only other home computer before abandoning the market. [ 20 ]
The Apple III , released in November 1980 as the successor to Apple II , was the first Apple computer not designed by Steve Wozniak , but rather by a committee of engineers led by Steve Jobs . The Apple III was sold as a business computer and housed a 1.8 MHz Synertek 6502A or 6502B processor and 128 KB of dynamic RAM . [ 21 ] The Apple III was capable of resolutions of up to 560 × 192 pixels in black and white and up to 280 × 192 in up to 16 simultaneous colors, as well as displaying 80 columns and 24 rows of text, both capital and lowercase. [ 22 ]
The Apple III failed commercially for multiple reasons. The computer, initially priced between $4,340 (equivalent to $16,562 in 2024) and $7,800 depending on options, was deemed "absurdly" high even for professional users. In addition, the internal structure of the first batch of units, described as "a disaster" by The Daily Telegraph , [ 23 ] used an aluminum enclosure inside the plastic case as the heat sink instead of a cooling fan, reputedly to meet Steve Jobs' demands for a silent computer and reduce RFI emissions, a severe problem affecting the Apple II. The result was that the Apple III would overheat, with the components lacking airflow, the motherboard being distorted by the heat and some chips slipping out of their sockets. 20 percent of the units failed to work as a result of the chips slipping during their shipment. Apple's public relations department later suggested that users lift the front of their units and drop them six inches off the desktop in hopes of re-seating the chips. A revised edition, launched in December 1981 for $3,495, addressed the overheating problem. [ 24 ] Lastly, the Apple III shipped with an emulator mode that nominally ensured compatibility with Apple II software. However, many Apple II programs directly wrote on memory using PEEK and POKE commands, which did not align with the Apple III's memory structure. [ 25 ] : 1 InfoCorp, a research firm, estimated that Apple sold only 75,000 units in December 1983, when the company was forced to redesign the Apple III to meet the Federal Communications Commission 's requirements for low RFI emissions. The new computer, Apple III Plus , at a price of $2,995, brought the figure to an estimated 120,000 units sold, but the brand's reputation remained poor, and it was discontinued in April 1984. [ 24 ] The original Apple III has been described as one of the worst computers of all time by PC World [ 20 ] and Maximum PC , [ 26 ] as well as one of the "20 spectacular failures" according to Byte [ 27 ] and one of "the 10 greatest flops in computer history" according to The Daily Telegraph . [ 23 ]
Lisa is a home computer created and launched by Apple Computer on January 19, 1983, succeeding the company's best-selling computer, the Apple II . Lisa was the first commercialized personal computer with a graphical user interface , as opposed to a command-line interface . Lisa began development in 1978 and was to be a business computer with a built-in green phosphor display, keyboard, and command-line interface due to ship in March 1981 and retail for $2,000. However, it was discovered that designing a computer around a bit-slice microprocessor would be too expensive, so the idea was abandoned. Jef Raskin 's visit to Xerox PARC , known among the American computer industry for the Xerox Alto , in the early 1970s also changed the course of Lisa's development. Raskin would have his student at University of California, San Diego , software engineer Bill Atkinson , convince Steve Jobs to visit PARC, and Jobs would recognize the value of GUIs in personal computers. Lisa's original project manager, Ken Rothmuller, who had complained that Trip Hawkins 's market requirements document's specifications for a GUI, a mouse, a local area network , file servers , and innovative applications would take too long and be too costly to incorporate into the machine, was replaced with John Couch . The Lisa team demanded more than a computer with a Xerox Alto-inspired GUI, which it had reinvented to include novelties such as the menu bar , pull-down menus , the one-button mouse, cutting and pasting with the clipboard , and the Trash can. Ultimately, the computer's release date was pushed back to 1983, retailing for $9,995 (equivalent to $31,555 in 2024) as it shipped with a Motorola 68000 , 1 MB of RAM , two 5¼-inch floppy drives, a 5 MB hard disk drive, a built-in 12 in (30 cm) monochrome display, and seven applications. [ 28 ]
Lisa struggled in the market for multiple reasons. The first was the price of the computer compared to its competitors, such as the popular IBM PC , which was introduced for $1,565. Secondly, its operating system, Lisa OS, supported preemptive multitasking , [ 29 ] but it could not keep up with multiple programs running at the same time as it was paired with the Motorola 68000. [ 30 ] The third reason was the unreliability of the hard drives, which were built in-house at Jobs' behest despite none at Apple having prior experience building one from scratch. The fourth reason was the lack of third-party software, which has been attributed to Lisa's bundled suite of applications that in turn discouraged developers from supporting it. Lastly, the press anticipation building up around what became Macintosh , further dimmed the machine's prospects. Apple took steps to reduce the cost of Lisa and lure back customers, eventually launching the Lisa 2 series with the base model now costing $3,495 and the high-end model, Lisa 2/10, having more memory and twice the capacity of the hard drive. However, Macintosh still outsold Lisa three to one. Apple rebranded Lisa 2/10 as Macintosh XL , also bundling it with a Macintosh emulator called MacWorks, and dropped the remaining Lisa models in January 1985 to consolidate the Macintosh line. Although the newly renamed computer's sales began to improve, it was officially discontinued on April 29, leaving an installed base of 60,000 units. [ 31 ] Due to its price and the arrival of the much cheaper Macintosh, Lisa was named one of "20 spectacular failures" by Byte . [ 27 ] It was also ranked No. 8 both on PC Magazine ' s and Maximum PC ' s lists of "The 12 Biggest PC Duds Ever" [ 19 ] and "The 16 Worst Failed Computers of All Time", [ 26 ] respectively, and listed by The Daily Telegraph as one of "the 10 greatest flops in computer history". [ 23 ]
The Coleco Adam was Coleco 's home computer released in October 1983, after the success of the company's video game console, ColecoVision , and against the backdrop of the ongoing video game crash . [ 32 ] Initially retailed for less than $750 (equivalent to $2,368 in 2024), it was a complete low-cost system that shipped with a 75-key typewriter-style keyboard, a daisy-wheel printer , one drive for a class of proprietary data cassettes called Digital Data Packs with the option of a second, a Zilog Z80A as its main processor, and 80 KB of RAM expandable to 144 KB, with 16 KB dedicated to the video display . It was also fully backwards-compatible with all ColecoVision game cartridges and accessories via its cartridge and expansion slots and was packaged with a word processor, two ColecoVision joysticks, and three Digital Data Packs, one containing a version of BASIC called SmartBASIC, one preformatted to store programs and files, and a native copy of Buck Rogers: Planet of Zoom . [ 33 ] [ 34 ]
The Adam was sold in two versions: as a standalone unit and as Expansion Module No. #3 for the ColecoVision, which upgraded it to a home computer. Jules H. Gilder of Byte praised the high-speed tape system in general despite it not using floppy disks and wrote "three cheers" for the keyboard, but criticized the lack of a COPY command for creating backups, called the manual for SmartBASIC the worst he had ever seen, questioned Coleco's decision to limit the computer's technical information to licensed developers, and raised the Adam's aforementioned reliability record. He found the machine's potential to not be fully realized and, believing it could fail like the Mattel Aquarius before it, recommended holding off purchasing one until Coleco fixed all the problems and delivered its promises. [ 33 ] Rushed into production ahead of Christmas 1983, the computer was plagued with numerous faults, with rates of returns of defective machines estimated to be as high as 60 percent. One dramatic fault was the system's ability to erase contents on a Digital Data Pack; this would result from a surge of electromagnetic energy emitted from the system's power supply on startup while the pack was left in the drive. The unusual daisy-chaining of the computer's components reduced the number of cables connected to the base, but also had the power supply located in the printer, [ 25 ] : 1 and many Adams were rendered useless due to defective printers. The Adam was a marketing disaster for Coleco, which had spent $258 million repairing the computers, and price reductions down to $300 and even vouchers for a $500 college scholarship could not compensate for its continued poor sales. Only about 95,000 units were shipped by the end of 1983, a far cry from the original promise of 500,000, [ 35 ] and Coleco discontinued the Adam in January 1985. [ 36 ] The Adam was voted by three editors for Creative Computing as one of the world's worst computers, [ 18 ] No. 3 on Maximum PC ' s list of "The 16 Worst Failed Computers of All Time", [ 26 ] and as the third worst PC of all time by PC World . [ 20 ]
The Osborne Executive is a self-named portable computer developed in 1983 by Osborne Computer Corporation , founded in 1981 by Adam Osborne , as the successor to its Osborne 1 . The Osborne 1, credited as the world's first mass-marketed portable computer, was highly successful, but it had drawn criticism for its small screen size, meager memory , and a shortage of high-quality software. The Executive was released to address these issues, with a larger screen and more memory. However, it also cost more than the Osborne 1, at $2,495 (equivalent to $8,129 in 2024). [ 37 ] As with the Osborne 1, the Executive was opened to reveal the built-in monitor, two floppy drives , and a detachable keyboard. [ 23 ]
Before its announcement of the Executive, Osborne Computer Corporation was known to sell lightweight computers and for far less than its competitors, yet earn twice as much profit as the industry average. It was also one of the fastest growing companies in United States history, boasting yearly sales approaching $100 million. Nonetheless, it soon faced stiff competition from rivals such as IBM and Japanese computer manufacturers, who were producing more affordable machines with improved features. Seeking to stay ahead of the competition and vastly expand his company's operations to a $1 billion business in two years, Adam Osborne chose to invest in the development of three new products: the Executive 1, the more powerful IBM PC-compatible Executive 2, and the Vixen , which was to be sold at a lower price than the Osborne 1, and it became immediately apparent that their announcements was the company's liability. The announcement of the Executive's imminent release evaporated the 25-month backlog of orders for the Osborne 1, depriving the company of its major source of income, aggravated by a combination of repeated delays of the product, increasing consumer expectations for a computer, and IBM's unexpectedly aggressive endeavor in the portable market. The Executive was perceived as expensive compared to the competition and outdated due to its continued used of the CP/M when other manufacturers had adopted the IBM PC as the standard. In September 1983, Osborne Computer filed for bankruptcy, with only the first Executive model brought to fruition (although the Vixen was later revived and released). [ 37 ] [ 38 ] [ 39 ] The Osborne effect refers to an upcoming product cannibalizing the sales of an existing product as a result of the company prematurely announcing the successor. [ 26 ]
The Commodore SX-64 is a portable computer based on Commodore International 's most popular model, the Commodore 64 , that debuted at the Winter Consumer Electronics Show of 1984, although it was first introduced at the same show a year earlier as a prototype. [ 40 ] With a 5 in (13 cm) color screen, it is the first commercial portable computer with a color display. The SX-64 weighed 23 pounds (10 kg), [ 41 ] measured 14.5×14.5×5 in (37×37×13 cm), and was almost fully compatible with software for the original Commodore 64, although it lacked a cassette tape port. The machine shipped with a built-in 1541 drive that sat below a compartment for storing disks and with enough space for a theoretical second drive. It was possible to connect the unit to a larger monitor, but it lacked an RF output , and it needed to be connected to an AC power outlet . [ 42 ]
Sales of the SX-64 have been considered to be poor, disappointing Commodore as it had hoped that the portable would prove popular among business users, who instead viewed it as simply a portable version of the consumer-oriented Commodore 64. [ 43 ] Along with a lack of focus on business software, the weight and small screen size were cited as factors contributing to the sluggish sales, as was the introductory price of $995 (equivalent to $3,011 in 2024)—nearly five times the price of a Commodore 64. The SX-64 was discontinued in 1986. [ 44 ] Despite its lackluster sales, the computer has become a collector's item. [ 45 ]
In February 1982, after the launch of its highly successful IBM PC , IBM started three projects for the PC XT , PC AT , and PCjr . [ 46 ] The PCjr would be the low-end home computer and become the first mass-marketed IBM product. Its original project manager, Bill Sydnes, sought a machine that would compete with the Apple II at a lower price, and, although its capabilities would be more limited than an IBM PC, they could be improved with hardware upgrades. However, six months into development, problems began to arise when Don Estridge , corporate vice president and head of the PC division, decided he disliked the concept of a consumer-oriented computer. The two disagreed over the PCjr's design and marketing. Particularly, Sydnes wanted it sold by general retail stores such as K Mart and J. C. Penney , but Estridge limited the vendors to conventional computer outlets, likely due to the tedium of stores applying for authorization. In addition, whereas Sydnes aimed for complete compatibility with the IBM PC , Estridge claimed that it would greatly cannibalize the PC's sales, although he agreed that the two computers ought to be compatible with spreadsheets and word processors. [ 47 ] Sydnes resigned in the spring of 1983 and was replaced by Dave O'Connor. The design and production problems he inherited from his predecessor as a result of internal strife, along with what Dan Wilkie saw as a free hand for a team who lacked the competence to build the PCjr successfully, caused the team to miss engineering delays, [ 48 ] ultimately pushing actual shipping to March 1984. [ 49 ]
The PCjr was available in two models: a base model for $669 (equivalent to $2,025 in 2024) and the higher-end Expanded Model for $1,269 (equivalent to $3,841 in 2024). The base model contains 64 KB of RAM and produces 40 columns for video output, while the Expanded Model, to which the base model can be upgraded, holds a total of 128 KB of RAM, supports 80-column video displays, and has a built-in floppy drive that loads 5¼-inch double-sided double-density disks with 360 KB of storage. Both models equipped with an Intel 8088 microprocessor, a keyboard that is connected with a detachable cord or wirelessly via the infrared link or, and PC DOS 2.1 as the operating system, but a display device had to be bought separately. Notably, the computer could display up to 16 colors and play up to three musical voices simultaneously—two clear advantages over the IBM PC—along with two slots for ROM cartridges, two joystick ports , [ 50 ] and an unusual "user-friendly" design feature allowing for expansion modules called " sidecars " that could be daisy-chained , contributing significantly to the unit's width. [ 25 ] : 2 [ 51 ]
The PCjr's November 1983 debut drew a positive press reception. Several publishers briefly ran magazines dedicated to the PCjr, including Compute! for the PC and PCjr , the spinoff PCjr Magazine , and a supplement called PCjr World . [ 52 ] Developers of add-ons for the original IBM PC viewed the PCjr as a lucrative investment, believing, according to PCjr Magazine , that the computer would be "a runaway success". [ 53 ] The computer's reception upon launch was mixed, with computer magazines such as Byte praising the graphical and sound capabilities, the software base, and the documentation and customer service. However, its limited expandiblility, including beyond 128 of memory, and high price for a home computer received criticism. One widely maligned feature was the chiclet keyboard of the first models, which Byte called "a real loser" [ 50 ] and which continued to draw the machine scorn that would persist even after IBM had shipped an advanced version of the PCjr at the end of July 1984 replacing it with a typewriter-style keyboard. The computer struggled to capture the home computer market, as customers expected a machine that would handle all the major software running on their office PCs flawlessly. [ 54 ] IBM's July revision of the PCjr also allowed for expansion to 512 KB of memory, [ 55 ] and the Enhanced Model now cost $999. [ 56 ] However, the improvements and the price reduction did little to help the PCjr commercially. [ 57 ] Finally, for Christmas 1984, in its last-ditch effort to save the PCjr, IBM pursued an aggressive, unprecedented marketing campaign and allowed vendors to sell a unit with a color monitor for $799. The holiday promotion significantly bolstered the PCjr's sales, with sources attributing 80 percent of a quarter of a million units sold in 1984. Nevertheless, at that price, the company failed to generate sufficient profit, and some industry experts believed that IBM was selling each unit at a loss. IBM ended the PCjr's production on March 19, 1985. [ 58 ]
In adding the PCjr to its list of "20 spectacular failures", Byte deemed the computer a "cruelly crippled cousin of the IBM PC" that was overshadowed by Apple's Macintosh and "died a laughingstock" a year later. [ 27 ] The PCjr topped PC Magazine ' s list of "The 12 Biggest PC Duds Ever", [ 19 ] was named the 13th worst tech product of all time by PC World , [ 7 ] and the 16th worst failed computer by Maximum PC , [ 26 ] and as one of "the 10 greatest flops in computer history" by The Daily Telegraph . [ 23 ]
The Macintosh Portable is the first battery-powered Macintosh and Apple Computer 's first portable computer , released in 1989 and featuring 1 MB of static random-access memory , a 16 MHz Motorola 68HC000 , a black-and-white active matrix LCD display, a floppy disk drive, an SCSI mode allowing the unit to be used as a hard drive, and a removable trackball device. It weighed 16 pounds (7.3 kg) and measured up to 4 inches (10 cm) thick, with lead-acid batteries contributing to the bulk of the weight. Reviews of the Portable were mixed, which tended to praise the LCD display, considered state-of-the-art technology at the time, but criticize the weight, size, and its high price, which ranged from $5,700 (equivalent to $14,459 in 2024) to over $7,000 depending on which features were included. In comparison, a DOS -running portable could weigh lest than 10 pounds (4.5 kg) and cost under $3,000, and portables from Poqet and Atari —coincidentally released almost concurrently with the Macintosh Portable—would weigh under 2 pounds (0.91 kg) and fit inside a coat pocket. [ 59 ] One analyst, David Cearly of Gartner Group , said, "One can only wonder how many people are willing to pay $8,000 for what essentially is a second computer." The editor of a personal computer newsletter in New York , Richard Shaffer, wrote, "This machine would have been OK 12 months or 18 months ago. But not today." [ 60 ]
According to Tom Thompson of Byte , for the two years it was on the market, the Portable was the butt of jokes due to its size and weight compared to DOS portables. Sales of the Portable proved disappointing, with only 10,000 units sold in the first quarter of its availability, short of Apple's projection of 50,000 units in the first year, and the computer was superseded by three models of the PowerBook . [ 61 ] [ 62 ] The Portable has been ranked No. 17 of PC World ' s list of "The 25 Worst Tech Products of All Time" [ 7 ] and No. 14 on Maximum PC ' s list of "The 16 Worst Failed Computers of All Time". [ 26 ] Complex placed it No. 29 on its list of "The 50 Worst Fails In Tech History", [ 3 ] and the Spanish magazine Computer Hoy also listed the Portable as the 4th worst computer, with both publications citing the weight, cost, and poor battery life and the latter calling it ugly. [ 63 ]
3Com was an American company known for developing modems and network interface controllers . 3Com conceived of a simple, low-cost Internet appliance that would keep a household wirelessly connected and virtually informed on Internet content, emails, and schedules from anywhere in the house, especially the kitchen. [ 64 ] The result was the October 17, 2000, launch of the 3Com Audrey , a trapezoidal QNX -based tablet that had an 8 in (20 cm) touchscreen controlled with a stylus and was available in five kitchen colors. [ 65 ] As well as with a bundled wireless keyboard, the user could write or draw with the stylus and send the handwritten messages by email. [ 66 ] The Audrey also featured a built-in microphone used to record voicemail and a knob stylized like a television dial used to select websites formatted for the Audrey. Notably, as Palm, Inc. was a spinoff of 3Com, the tablet's HotSync technology allowed multiple Palm devices to synchronize with the unit's PIM . [ 67 ]
PC Magazine became less skeptical of Internet appliances after testing the Audrey, ultimately recommending it. [ 67 ] In contrast, David Pogue of The New York Times , while writing that the device "st[ood] head and shoulders" among the competition, criticized the small keyboard and the device's feminine design, which he viewed as patronizing. [ 66 ] Like other Internet appliances, the Audrey failed to take off due to low consumer demand for a computer that cost as much as a full-fledged one, and was thus discontinued on June 1, 2001, [ 68 ] although it gained popularity among hackers who reprogrammed the device for other purposes such as controlling household appliances. [ 69 ] For its limited functionality and lack of broadband support, PC World added the Audrey as one of its "(Dis)Honorable Mentions" on its list of the worst tech products, deeming it "a symbol" of why Internet appliances failed. [ 7 ] PC Magazine included the Audrey on its list of "The Biggest Hardware Flops of All Time", citing the price and the unfortunate timing of its release amid the dot-com crash. [ 4 ]
The Power Mac G4 Cube is a Mac developed by Apple Inc. between July 2000 and 2001. [ 70 ] Conceived as a miniaturized but powerful computer by then-Apple CEO Steve Jobs , it was marketed as being between the consumer iMac G3 and the professional Power Mac G4 in the product range. The computer, designed by Jony Ive , was encased and suspended in acrylic glass measuring 7.7×7.7×9.8 in (20×20×25 cm), with the transparent plastic intended to lend the impression of a floating machine. [ 71 ]
While the Cube received positive reviews and awards for its design, reviewers noted that it was expensive compared to its power and lacked expandability. It was further criticized for its tendency to develop cracks in its case, significantly impacting sales of a computer favored by potential buyers for its aesthetics. [ 19 ] The product was an immediate commercial failure, selling only about 150,000 units before it was discontinued just less than a year after its release. [ 70 ] Macworld ' s Benj Edwards wrote that consumers regarded the Cube as "an underpowered, over-expensive toy or [...] an emotionally inaccessible, ultra-geometric gray box suspended in an untouchable glass prison". [ 72 ] Maximum PC ranked the Cube No. 2 on its list of "The 16 Worst Failed Computers of All Time", citing its costs and cosmetic defects. [ 26 ] Despite its commercial failure, the Cube influenced future Apple products; capacitive touch would reappear in Apple's iPod and iPhone lines, [ 71 ] and the company's miniaturization efforts would benefit computers such as the iMac G4 and the Mac Mini , whose design was inspired by the Cube. [ 70 ]
The JooJoo was conceived by TechCrunch founder Michael Arrington , who in a 2008 blog post envisioned "dead simple Web tablet" that would cost about $200. [ 73 ] Originally named the CrunchPad, the tablet was produced by Singapore-based Fusion Garage, headed by CEO Chandra Rathakrishnan. However, despite the prototypes' positive feedback from the media, the Arrington–Rathakrishnan partnership would hamper the device's development, [ 74 ] with Arrington canceling plans for the tablet and Fusion Garage renaming it the JooJoo and raising the retail price to $499. While more expensive than a typical netbook , Rathakrishnan claimed that the original pricing was unrealistic. [ 75 ] Eventually, the feud culminated in a lawsuit against Fusion Garage, [ 73 ] further delaying the tablet's launch until March 29, 2010, as the official release date, although the legal battle hindered actual shipping for a few days. [ 76 ] Meanwhile, Apple's widely anticipated iPad , formerly considered a competitor of the JooJoo, was launched on April 3 the same year for the same price, undercutting Fusion Garage's innovative edge over Apple. [ 74 ]
The JooJoo was panned by reviewers upon release. PC Magazine called it a "woefully overpriced" "device that's essentially a Web browser trapped under a huge touch screen", and Engadget criticized the performance and short battery life as a result of the combination of the device's Intel Atom processor and Nvidia Ion chipset. Although its Adobe Flash support was seen as an advantage over the iPad, both publications criticized the device's poor responsiveness to user input and the generally frustrating user experience. [ 77 ] [ 78 ] A court document from the lawsuit revealed that only 90 preorders for the tablet were made, of which 15 were canceled. [ 76 ] As of late April, the JooJoo reportedly sold only 64 units, [ 79 ] and on November 19, it was discontinued. [ 80 ] Due to its abysmal performance critically and in the marketplace, the JooJoo was named by PC Magazine as one of "The Biggest Hardware Flops of All Time". [ 4 ]
Kin was a short-lived line of mobile phones created by Microsoft executive J Allard . Microsoft acquired Danger, Inc. , known for the T-Mobile Sidekick , and its cloud computing intellectual property for $500 million in 2008 to kick-start its project. Kin's development was stunted by corporate politics between Allard and senior vice president Andy Lees, who was spearheading the development of what became Windows Phone 7 . The two teams were separate, and Allard sought an original phone that would not share the same basis as Lees' project. However, Lees was reportedly jealous of Kin and probably concerned that it was distracting the Windows Phone team and diverting its resources. After enough pressure, Lees took the reins of Kin's development, and Allard's influence over the project dwindled considerably. [ 81 ] [ 82 ]
Under the auspices of its new leadership, Kin was redesigned from the ground up in keeping with Windows Phone. As a result, the phone was delayed a total of 18 months [ 83 ] before being finally released on May 6, 2010, exclusively through Verizon Wireless . Marketed as a " chic " device toward teenagers and young adults, [ 83 ] it was available in two models, Kin ONE for $50 and Kin TWO for $100, with 4 GB and 8 GB of storage, respectively, and data automatically backed up in the cloud—innovative for a phone at the time. [ 84 ] While a desktop application called Kin Studio garnered unanimous praise, the devices themselves were criticized for the quality and quantity of built-in software and the mandatory $30 monthly data plan from Verizon, which PC World described as "appalling" and "hard to swallow". The devices were also seen as not true smartphones, given the inability to download third-party applications and games. [ 85 ] Kin failed to take off commercially, with estimates of sales below 10,000 units, and Microsoft halted both models' production on June 30. [ 83 ] Along with the negative reception, Microsoft's confusing attempts to distinguish the KIN OS from the platform of then-upcoming Windows Phone 7 and the company's mistake of not touting the device's automatic backup feature were cited as some of the factors for the poor sales. [ 84 ] Later that year, Verizon relaunched the phones, now rebranded ONEm and TWOm, as feature phones , with a modified operating system and improved software, but they did nothing to recover the brand's sales, and in August 2011, the models were discontinued. [ 83 ]
The HP TouchPad is a tablet computer designed by Hewlett-Packard . The TouchPad's development began after HP acquired Palm, Inc. , known for its personal digital assistants , for about $1.2 billion in July 2010. The tablet was announced in February 2011, with HP insisting a March release, but Palm pushed back, citing that the TouchPad barely functioned, and it was ultimately launched on July 1 that year. The TouchPad was soon recognized as a commercial failure, with tablets reportedly piling up at Best Buy stores and the electronics chain sending some back and refusing new deliveries. Its introductory prices of $499 and $599 for models with 16- and 32 GB of storage, respectively, compared to those of the iPad 2 and the bugs found in the tablet's webOS 3.0 operating system were cited as reasons for the failure. [ 86 ] HP attempted to lure customers with a rebate program, a weekend-only discount, and finally a permanent $100 price decrease in a single week in August, all of which proved fruitless. [ 87 ] The company discontinued the TouchPad on August 18—just 48 days after it was launched, with Best Buy reporting only 25,000 of the 270,000 units in its stock. Hours later, a fire sale was held for the 16- and 32 GB models for $99 and $149, respectively. This resulted in the TouchPad quickly selling out, with 350,000 units reportedly sold in the first 24 hours. [ 88 ] According to an NPD Group report published in November, the TouchPad became the best-selling non-iPad tablet in the United States in the first ten months of 2011, accounting for 17 percent of the 1.2 million tablets sold there. [ 89 ] Nevertheless, for the fiscal year of 2011, HP wrote off $885 million in assets and another $755 million in costs of pulling out of the webOS market. [ 90 ]
The Fire Phone was Amazon 's first smartphone. As of June 2024 [update] , it remains Amazon's only smartphone. [ 91 ] The company touted the Fire Phone's Dynamic Perspective and Firefly features. Dynamic Perspective uses the phone's four cameras to detect where the user is looking to apply a 3D effect to perspectives and gestures, and Firefly is a virtual assistant that can identify around 100 million products, including those sold by Amazon, using the phone's sensors. [ 92 ] Launched on July 25, 2014, the Fire Phone was available with 32 GB of storage for $649.99 (equivalent to $862 in 2024) or 64 GB for $749.99, the prices of which were reduced by $450 if purchased with a two-year AT&T contract. [ 93 ]
The Fire Phone received a lukewarm response from reviewers, who praised the free one-year subscription to Amazon Prime and the company's Mayday feature, which offers technical support, but criticized the phone's battery life, low amount of available software, and poor hardware design, which Farhad Manjoo , writing for The New York Times , described as "gimmicky". The phone was also seen as lacking incentive for iPhone and Samsung Galaxy users to buy one. The phone failed commercially, with Amazon writing down $170 million on unsold units and The Guardian estimating that only around 35,000 units were sold a month after it was launched, and the phone's price with the AT&T contract was reduced to just 99 cents by September. [ 94 ] [ 95 ] Amazon discontinued the Fire Phone on September 8, 2015. [ 96 ]
The Samsung Galaxy Note 7 was the sixth main device in Samsung 's Galaxy Note line of Android phablets . A high-end smartphone, it featured a 5.7 in (14 cm) screen and a stylus. The Note 7 was unveiled to critical acclaim before its August 19, 2016, launch, with reviewers lauding the design and ergonomics and a screen that was larger and sharper than that of Apple 's iPhone 6s . The device's retina scanner, waterproofing, and rear-facing dual cameras were also praised, as was the lithium-ion battery 's capacity, which, at 3,500 mAh , allowed up to 36 hours of constant use without recharging. [ 97 ] [ 98 ]
However, the praise and enthusiasm soon dissipated in the wake of numerous reports of the phones catching fire, in some cases exploding. Samsung halted production on September 2 as the company scrambled to send replacements and the news of the incidents wiped $26 billion off of the company's stock value. The problem, as an internal investigation concluded in January 2017 determined, was a defect in the batteries of the first batch of phones, which had been manufactured by Samsung SDI . The upper right corner of the battery's casing left too little room for the negative electrodes, leading to the electrodes being bent in each of the 200,000 recalled devices tested and stressing the insulating separator placed between the positive and negative electrode foils. The negative electrodes were also found to be too long, and the batteries of some units had too thin separators. If the separator failed, the battery would short-circuit , causing catastrophic thermal runaway . By September 21, retail stores began exchanging replacement devices containing batteries now supplied by Amperex Technology , and sales of the Note 7 resumed, but reports of the devices also catching fire began to surface. The January investigation found that the replacements' batteries, due to poor welding, had burrs on the positive electrode that would scrape the insulation tape and the separator, and some units were missing insulation tape, both rendering the devices prone to the same catastrophic failure. [ 99 ] [ 100 ] On October 11, 53 days after the Note 7 was launched, Samsung recalled 2.5 million units—the largest in smartphone history—and permanently discontinued production. [ 98 ]
The fiasco was estimated to cost Samsung $17 billion. [ 97 ] [ 98 ] Airlines across the United States, Asia, Europe, Australia, and New Zealand moved to ban the devices from flights. [ 101 ] Due to a reputation for combusting that has overshadowed its popularity, PC Magazine names the Note 7 as one of "The Biggest Hardware Flops of All Time". [ 4 ]
Apple Computer 's Macintosh debuted in January 1984 after a well-received introduction, but struggled to see widespread adoption by businesses. Apple sought a " killer application " that could boost the Macintosh's stagnant sales. When Lotus Development Corporation , known for its Lotus 1-2-3 spreadsheet application, itself considered the killer application for the IBM PC , [ 102 ] announced Lotus Jazz in November, Apple CEO John Sculley , who was present at the product's introduction, hailed it as "strategically significant for Apple", calling it "a very important day for, obviously, Lotus—but also for Apple and the industry". Jazz is a productivity suite similar to Lotus Symphony for MS-DOS that was bundled with a word processor , a spreadsheet program, a database manager, a graphics editor, and telecommunications software. The software package was planned for a March 1985 release, but ended up shipping in August, selling for $595 (equivalent to $1,740 in 2024). [ 103 ]
Unlike Lotus 1–2–3, Jazz's performance in the market was lackluster, capturing only 9 percent of the Macintosh software market compared to the top-selling software in February 1986, Microsoft Excel , with 36 percent of the share. By April, the company had sold only 42,000 copies. [ 104 ] The sales were partly attributed to the high pricing and the failure of Lotus Development to use the 1-2-3 brand. [ 102 ] The suite's reception was also poor. PC Magazine summed up the product as "a klutzy multifunction program that fell well short of Lotus's reputation for fast, innovative highly functional software". [ 105 ] The software's use of copy protection was also criticized. [ 102 ] Lotus Development co-founder Mitch Kapor admitted that Jazz was an "overly ambitious" project plagued with bugs that took the team longer to develop than expected. [ 106 ] An update, called Lotus Modern Jazz, was planned for a 1988 release, but Lotus Development canceled it later that year. [ 107 ] PC Magazine listed the original Jazz as one of "The 20 Biggest Software Flops of All Time". [ 105 ]
Microsoft Bob was a Microsoft software package that provided a graphical interface for users of Windows 3.x . Designed to make using Windows simpler, the software replaced the Program Manager and its pull-down menus and icons with a house in which one of 11 cartoon characters, the default being Rover the dog, guided the user with instructions inside speech balloons . The rooms consisted of objects that could be clicked on to run one of eight programs. For example, clicking on a piece of paper would allow the user to type a letter. [ 108 ] [ 109 ]
Microsoft touted Bob as the first kind of a social interface, and many analysts predicted that the interface's style could supplant the desktop-and-folders one invented by the Macintosh . Despite early praise for its presentation, Bob received generally negative reviews, with reviewers criticizing the room style of the interface, the guides, the lack of customizability and manual, high system requirements, and practicality. Stephen Manes , writing for The New York Times , ended his review by referring to the product as a "toy". [ 110 ] The apparent lack of an embargo on reviews between January and Bob's March 31 release negatively affected product sales; by early 1996, when Bob was discontinued, only about 58,000 copies were ever sold, compared to about 2.75 million licenses of Windows 95 sold in its first month, according to PC Data . [ 109 ]
Microsoft Bob is remembered as the application that the Comic Sans font was designed for (but was ultimately left out of) and for the debut of the characters Clippy , an anthropomorphic paperclip, and Rover. Comic Sans would later be bundled with Windows, and Clippy and Rover would reappear as assistants for Microsoft Office versions 97 to 2003 and Windows XP 's search feature, respectively. [ 109 ] Time named Bob and Clippy as two of "The 50 Worst Inventions", calling the former an "expensive and overly cutesy" piece of software that was "designed around Clippy". [ 8 ] PC World ranked the product No. 7 on its list of "The 25 Worst Tech Products of All Time" [ 7 ] and Complex No. 27 on its list of "The 50 Worst Fails In Tech History". [ 3 ]
Windows Phone is a discontinued mobile operating system that debuted in October 2010 [ 111 ] as a major update for and succeeding Microsoft 's earlier Windows Mobile , which itself has roots in the Windows CE -based Pocket PC . Appearing first as Windows Phone 7 after as much as about six years in the making, Windows Phone entered the market with stiff competition from Apple 's iPhone and Google 's Android . The operating system stood out from its rivals in its use of a simplified design language called Metro and also in grouping related applications into "hubs" intended to display and allow for important information and tasks without the need to switch between applications constantly. Reception of Windows Phone 7 was mixed, with reviewers praising the operating system's interface design, but criticizing the lack of basic features found in the iPhone and Android, such as copy-and-paste , custom ringtones, and tethering . Third-party applications were also limited by the available APIs and the multitasking extremely so, and the pace at which Microsoft added the missing features in updates further exacerbated user frustrations. However, Windows Phone's prospects were drastically improved a year later when Nokia , then the world's largest smartphone manufacturer, released the first of its Nokia Lumia phones, the 710 and the higher-end 800 , both with the Windows Phone 7.5 update installed; the update and the devices were received more favorably compared to the original Windows Phone at launch, though there were concerns regarding the price of the phones. Even so, Windows Phone consistently trailed Android and iPhone in shares of the smartphone market, [ 112 ] [ 113 ] peaking in its lifetime at just 3.6 percent in the third quarter of 2013, according to Gartner . [ 114 ]
In late 2012, Microsoft released an upgrade called Windows Phone 8 , now based on the Windows NT kernel (the same as Windows 8 and Windows RT ) supporting multi-core CPUs , near-field communication , microSD cards, and high-definition screens and making important software improvements such as a more customizable Start screen [ 113 ] and the ability to capture screenshots. Notable devices using the new operating system include the Nokia Lumia 520 , which remains the best-selling Windows Phone device, and the Nokia Lumia 1020 , known for its 41- megapixel camera. [ 112 ] [ 111 ] As with its predecessor, Windows Phone 8 received mixed reviews upon release, with users again criticizing the lack of basic features such as a screen rotation lock and custom notification sounds and the pace at which said features would be added in updates—a common critique that the Windows Phone family had come to endure— as well as the dearth of third-party applications on launch and the incomplete feel of the operating system. A major update, Windows Phone 8.1 , was released in April 2014, introducing a plethora of new features and improvements, among them a Swype -style keyboard, which briefly held a Guinness World Record for the fastest onscreen keyboard, and a widely anticipated virtual assistant called Cortana . [ 112 ] [ 113 ] Meanwhile, Nokia continued to expand its share of the Windows Phone market [ 113 ] such that, by September 2013, the Lumia phones had overwhelmingly dominated Windows Phone sales. Nevertheless, the Finnish phone manufacturer was designing and selling the phones at a loss, and Nokia was planning the launch of low-cost phones running a forked version of Android, threatening Microsoft's mobile ambitions. Microsoft acquired Nokia's phone business later in April 2014 in a deal worth about $7.2 billion. However, in July, Microsoft announced the biggest layoffs in company history, affecting 18,000 people, of whom over two-thirds had just joined following the Nokia acquisition. The following year, Microsoft was also forced to write off $7.6 billion—more than the entire cost of the acquisition—and lay off a further 7,800. [ 112 ]
The last major iteration of Windows Phone, Windows 10 Mobile , was released in early 2016, adding support for Universal Windows Platform apps, which are cross-compatible with Windows devices and Xbox One . It also featured Continuum , an application that provides a desktop-like interface for users who connect their devices to a keyboard and a mouse, and then to a display. [ 113 ] Still, developers saw little incentive to support the mobile operating system, [ 112 ] and the Windows Phone devices continued their downward trajectory. While Microsoft posted revenue of $1.397 billion for its hardware in the third quarter of fiscal year 2015, that figure plunged to $735 million the next year before collapsing to just $5 million the year after. [ 115 ] On October 8, 2017, Microsoft vice president of operating systems Joe Belfiore tweeted that the company would end mainstream support for Windows Phone, due to its low user base. According to IDC , shares had dwindled to a mere 0.1 percent by March 2017. [ 116 ] The last update, version 1709 for Windows 10 Mobile, arrived on December 10, 2019. [ 117 ] Due to the operating system's eventual inability to eat into the iPhone's and Android's market dominance, The Verge considers Windows Phone overall to be a failure. [ 111 ] | https://en.wikipedia.org/wiki/List_of_commercial_failures_in_computing |
There are a number of commercial products based on Red Hat Enterprise Linux (RHEL). Information about these products and the version of RHEL they are based on is often difficult to come by, since this fact is not widely publicised. Sometimes it is possible to run the 'uname -r' command to get the kernel release and then cross-reference it with the RHEL version history. | https://en.wikipedia.org/wiki/List_of_commercial_products_based_on_Red_Hat_Enterprise_Linux |
In computer engineering , logic synthesis is a process by which an abstract specification of desired circuit behavior, typically at register transfer level (RTL), is turned into a design implementation in terms of logic gates , typically by a computer program called a synthesis tool . Common examples of this process include synthesis of designs specified in hardware description languages , including VHDL and Verilog . [ 1 ] Some synthesis tools generate bitstreams for programmable logic devices such as PALs or FPGAs , while others target the creation of ASICs . Logic synthesis is one step in circuit design in the electronic design automation , the others are place and route and verification and validation .
The roots of logic synthesis can be traced to the treatment of logic by George Boole (1815 to 1864), in what is now termed Boolean algebra . In 1938, Claude Shannon showed that the two-valued Boolean algebra can describe the operation of switching circuits. In the early days, logic design involved manipulating the truth table representations as Karnaugh maps . The Karnaugh map-based minimization of logic is guided by a set of rules on how entries in the maps can be combined. A human designer can typically only work with Karnaugh maps containing up to four to six variables.
The first step toward automation of logic minimization was the introduction of the Quine–McCluskey algorithm that could be implemented on a computer. This exact minimization technique presented the notion of prime implicants and minimum cost covers that would become the cornerstone of two-level minimization . Nowadays, the much more efficient Espresso heuristic logic minimizer has become the standard tool for this operation. [ needs update ] Another area of early research was in state minimization and encoding of finite-state machines (FSMs), a task that was the bane of designers. The applications for logic synthesis lay primarily in digital computer design. Hence, IBM and Bell Labs played a pivotal role in the early automation of logic synthesis. The evolution from discrete logic components to programmable logic arrays (PLAs) hastened the need for efficient two-level minimization, since minimizing terms in a two-level representation reduces the area in a PLA.
Two-level logic circuits are of limited importance in a very-large-scale integration (VLSI) design; most designs use multiple levels of logic. Almost any circuit representation in RTL or Behavioural Description is a multi-level representation. An early system that was used to design multilevel circuits was LSS from IBM. It used local transformations to simplify logic. Work on LSS and the Yorktown Silicon Compiler spurred rapid research progress in logic synthesis in the 1980s. Several universities contributed by making their research available to the public, most notably SIS from University of California, Berkeley , RASP from University of California, Los Angeles and BOLD from University of Colorado, Boulder . Within a decade, the technology migrated to commercial logic synthesis products offered by electronic design automation companies.
The leading developers and providers of logic synthesis software packages are Synopsys , Cadence , and Siemens . Their synthesis tools are Synopsys Design Compiler, Cadence First Encounter and Siemens Precision RTL.
Logic design is a step in the standard design cycle in which the functional design of an electronic circuit is converted into the representation which captures logic operations , arithmetic operations , control flow , etc. A common output of this step is RTL description . Logic design is commonly followed by the circuit design step. In modern electronic design automation parts of the logical design may be automated using high-level synthesis tools based on the behavioral description of the circuit. [ 2 ]
Logic operations usually consist of Boolean AND, OR, XOR and NAND operations, and are the most basic forms of operations in an electronic circuit. Arithmetic operations are usually implemented with the use of logic operators.
With a goal of increasing designer productivity, research efforts on the synthesis of circuits specified at the behavioral level have led to the emergence of commercial solutions in 2004, [ 3 ] which are used for complex ASIC and FPGA design. These tools automatically synthesize circuits specified using high-level languages, like ANSI C/C++ or SystemC, to a register transfer level (RTL) specification, which can be used as input to a gate-level logic synthesis flow. [ 3 ] Using high-level synthesis, also known as ESL synthesis, the allocation of work to clock cycles and across structural components, such as floating-point ALUs, is done by the compiler using an optimisation procedure, whereas with RTL logic synthesis (even from behavioural Verilog or VHDL, where a thread of execution can make multiple reads and writes to a variable within a clock cycle) those allocation decisions have already been made.
Typical practical implementations of a logic function utilize a multi-level network of logic elements. Starting from an RTL description of a design, the synthesis tool constructs a corresponding multilevel Boolean network .
Next, this network is optimized using several technology-independent techniques before technology-dependent optimizations are performed. The typical cost function during technology-independent optimizations is total literal count of the factored representation of the logic function (which correlates quite well with circuit area).
Finally, technology-dependent optimization transforms the technology-independent circuit into a network of gates in a given technology. The simple cost estimates are replaced by more concrete, implementation-driven estimates during and after technology mapping. Mapping is constrained by factors such as the available gates (logic functions) in the technology library, the drive sizes for each gate, and the delay, power , and area characteristics of each gate. | https://en.wikipedia.org/wiki/List_of_commercial_tools_for_logic_synthesis |
Insulin as a medication is sold under many different trade names, which are listed below. A dagger symbol (†) indicates discontinued brands. Different brands of insulin may offer any of the following preparation methods: vials , pens , cartridges, IV bags or inhalers . [ 2 ]
All insulin analogues and non-analogue insulins work by enhancing glucose uptake in tissues and reducing glucose production by the liver . [ 3 ] Insulin is prescribed for conditions such as type 1 diabetes , type 2 diabetes , [ 4 ] gestational diabetes , [ 5 ] and diabetes-related complications such as diabetic ketoacidosis . [ 6 ] Additionally, insulin is administered alongside glucose to treat elevated blood potassium levels ( hyperkalemia ). [ 7 ]
While all types are commonly referred to as insulin, the term in its strictest sense applies to the naturally occurring molecule, whereas insulin analogues have modified structures to alter their pharmacokinetics . [ 8 ]
Certain insulin brands can also have differing names regionally, such as how Novolog is called Novorapid outside of the United States. [ 9 ] [ 10 ] Brands may also be commonly referred to with different names. For example, Basaglar, Abasaglar, and Abasria all refer to the same brand. Abasria is the brand's former name, [ 11 ] while Basaglar and Abasaglar are regional. [ 11 ] [ 12 ] [ 13 ]
The three companies which produce the most insulin are Lilly , Novo Nordisk and Sanofi . These corporations control 99% of the global market by value and 96% by volume. [ 14 ] However, other smaller pharmacutical companies also produce insulin, such as Mannkind (Afrezza), Viatris (Semglee), Lupin (Lupisulin), Baxter (Myxredlin), Biocon (Basalog), Darou Pakhsh (Dipisulin), Glenmark (Insulong), Wockhardt (Wosulin), Julphar (Jusline), SciGen (SciLin), Bioton (Gensulin), and Cadila (Humanext). Many insulin analogues are available unbranded. [ 15 ] [ 16 ]
Insulin lispro, marketed under the brand name Humalog among others, is a modified form of medical insulin used to treat both type 1 and type 2 diabetes. [ 17 ] It is administered subcutaneously through injection or an insulin pump . [ 18 ] [ 19 ] The effects typically begin within 30 minutes and last for about 5 hours. [ 17 ] Sometimes, a longer-acting insulin, such as insulin NPH , is also used. [ 20 ]
Common side effects include low blood sugar , while more serious side effects may include low blood potassium . [ 21 ] It is generally considered safe for use during pregnancy and breastfeeding. [ 22 ] [ 23 ] It functions similarly to human insulin by increasing glucose uptake in tissues and reducing the amount of glucose produced by the liver in gluconeogenesis . [ 24 ]
Insulin lispro was first approved for use in the United States in 1996. [ 18 ] [ 25 ] [ 26 ] It is a synthetic analogue of human insulin, created by swapping two amino acids . [ 27 ] In 2022, it ranked as the 70th most commonly prescribed medication in the United States, with over 9 million prescriptions. [ 28 ] [ 29 ] Insulin lispro is available under a generic label from Lilly. [ 30 ]
Insulin aspart, marketed under the brand name Novolog among others, is a modified type of medical insulin used to treat both type 1 and type 2 diabetes. [ 38 ] It is typically administered by injection under the skin (into the abdomen, buttocks, thighs, or upper arms), but can also be injected into a vein. [ 39 ] Its maximum effect occurs after about 1–3 hours and lasts for 3–5 hours. [ 40 ] A biosimilar version of insulin aspart, insulin-aspart-szjj, was released in 2025. [ 41 ]
Common side effects include low blood sugar, allergic reactions, itchiness, and pain at the injection site. Serious side effects may include low blood potassium. [ 38 ] It is generally considered safe to use during pregnancy and breastfeeding. [ 42 ] [ 38 ] It works similarly to human insulin by enhancing glucose uptake in tissues and reducing glucose production by the liver. [ 38 ] It is a synthetic form of human insulin, with a single amino acid change, replacing proline with aspartic acid at the B28 position. [ 43 ]
Insulin aspart was approved for medical use in the United States in 2000. [ 44 ] In 2022, it was the 76th most commonly prescribed medication in the United States, with over 8 million prescriptions. [ 28 ] [ 45 ] Its production involves yeast that have had the gene for insulin aspart inserted into their genome, allowing the yeast to produce the insulin, which is then harvested from the bioreactor . [ 46 ] [ 47 ] Insulin aspart is available unbranded from Novo Nordisk. [ 15 ] [ 16 ]
Insulin glulisine is a rapid-acting modified form of insulin used to treat diabetes. It differs from human insulin by replacing the amino acid asparagine at position B3 with lysine and the lysine at position B29 with glutamic acid . [ 56 ] When injected subcutaneously, it enters the bloodstream faster than regular human insulin (RHI). [ 57 ] It was developed by Sanofi. The most common side effect is hypoglycemia (low blood glucose levels). [ 58 ]
Insulin glulisine was approved for medical use in the United States [ 59 ] [ 60 ] and the European Union in 2004. [ 61 ] It is currently patented by Sanofi, and is therefore only produced by said company under the brand name Apidra. [ 62 ]
Inhalable insulin, also known as technosphere insulin, [ 63 ] is a powdered form of insulin, delivered with an inhaler into the lungs where it is absorbed. [ 64 ] In general, inhaled insulins have been more rapidly absorbed than subcutaneous injected insulin, with faster peak concentration in serum and more rapid metabolism. [ 65 ]
Exubera, developed by Inhale Therapeutics (later named Nektar Therapeutics ), became the first inhaled insulin product to be marketed, in 2006 by Pfizer , but poor sales led Pfizer to withdraw it in 2007. [ 66 ] Afrezza, a monomeric inhaled, ultra rapid-acting insulin developed by Mannkind , was approved by the FDA in 2014 [ 67 ] and is the only inhaled insulin commercialized as of 2025. [ 68 ]
Regular insulin, also known as neutral insulin or soluble insulin, is a type of short-acting medical insulin. [ 71 ] It is used to treat type 1 diabetes, type 2 diabetes, gestational diabetes, and complications such as diabetic ketoacidosis and hyperosmolar hyperglycemic states . [ 72 ] It is also used with glucose to treat high blood potassium levels . [ 73 ] Typically administered by injection under the skin, it can also be injected into a vein or muscle . [ 71 ] Its effects usually begin within one hour and last around four hours. [ 74 ]
The most common side effect is low blood sugar. [ 72 ] Other side effects may include pain or skin changes at the injection sites, low blood potassium, and allergic reactions. [ 75 ] It is relatively safe to use during pregnancy for the baby. [ 76 ] Regular insulin can be derived from the pancreas of pigs or cows, with human versions created by modifying pig insulin or using recombinant technology. [ 71 ]
Insulin was first used as a medication in Canada by Charles Best and Frederick Banting in 1922. [ 77 ] It is listed on the World Health Organization's List of Essential Medicines . [ 78 ] In 2017, it ranked as the 209th most commonly prescribed medication in the United States, with over 2 million prescriptions. [ 79 ] There are also versions available that are mixed with longer-acting insulin, such as NPH insulin. [ 71 ] In 2020, the combination of human insulin and insulin isophane was the 246th most commonly prescribed medication in the US, with more than 2 million prescriptions. [ 28 ] [ 80 ]
Regular insulin is commonly sold under the name of an insulin product line followed by the letter R. [ 81 ]
Semilente insulin was an insulin from the lente family of insulin that was derived from pork. [ 105 ] It had smaller crystals than untralente, so it was absorbed faster, and therefore had a shorter duration of action which was similar to that of regular insulin. [ 106 ] Like the other lente insulins, it was phased out in the early 2000s. [ 107 ] It was produced by Lilly under the name Semilente Iletin I. [ 108 ]
Buffered regular insulin is a variation of regular insulin that is specifically formulated for use only in insulin pumps . [ 109 ] [ 110 ] [ 111 ]
NPH insulin, also known as isophane insulin, is an intermediate-acting insulin used to manage blood sugar levels in individuals with diabetes. The name NPH is an abbreviation for "neutral protamine Hagedorn", referring to neutral pH (pH = 7), protamine a protein attached to the insulin molecule, and Hans Christian Hagedorn , the insulin researcher who developed this formulation. [ 114 ] It was designed to enhance insulin delivery and is one of the early examples of engineered drug delivery. [ 114 ]
It is typically administered through subcutaneous injection once or twice daily. [ 114 ] Its effects usually begin within an hour and last for 24 hours. [ 115 ] There are versions available that are premixed with short-acting insulins, such as regular insulin . [ 71 ] The most common side effect is low blood sugar (hypoglycemia). Other potential side effects may include pain or skin changes at the injection sites, low blood potassium, and allergic reactions. [ 115 ] It is generally considered safe for use during pregnancy for the fetus. [ 115 ] [ 76 ] NPH insulin is produced by mixing regular insulin and protamine in precise proportions with zinc and phenol to maintain a neutral pH and form crystals. There are versions based on human and pig insulin. [ 114 ]
Protamine insulin was first created in 1936, and NPH insulin was introduced in 1946. [ 114 ] It is included in the World Health Organization's List of Essential Medicines [ 78 ] In 2020, insulin isophane was the 221st most commonly prescribed medication in the United States, with more than 2 million prescriptions. [ 28 ] [ 114 ]
NPH insulin is commonly sold under the name of an insulin product line followed by the letter N. [ 116 ]
Lente insulin (derived from the Italian word lento, meaning "slow"), also known as insulin zinc suspension, was an intermediate-acting insulin that is no longer used in humans. [ 107 ] Its effects begin one to two hours after administration, with peak activity occurring approximately 8 to 12 hours post-injection, and some residual effects lasting beyond 24 hours. [ 134 ]
Manufacturers discontinued Lente insulin and other similar insulin analogs in the mid-2000s, and it is no longer approved for human use in the United States. [ 135 ] [ 136 ] [ 137 ] This decision was partly due to the medical community's preference for more predictable insulin formulations, such as recombinant NPH insulin. [ 138 ]
Similarly to the modern brands of NPH and regular insulin, which are still sold, lente insulins would be marketed under the name of the rest of the insulins in a brand's product line, followed by the letter L. [ 139 ]
Insulin detemir is a long-acting modified form of medical insulin used to treat both type 1 and type 2 diabetes. [ 143 ] It is administered through subcutaneous injection. Its effects last for up to 24 hours. [ 143 ] [ 144 ]
Common side effects include (hypoglycemia, allergic reactions, pain at the injection site, and weight gain. [ 143 ] It appears to be safe for use during pregnancy and breastfeeding. [ 145 ] [ 146 ] Insulin detemir works by increasing the amount of glucose absorbed by tissues and reducing the amount of glucose produced by the liver. [ 143 ]
Insulin detemir was approved for medical use in the European Union in June 2004 and in the United States in June 2005. [ 147 ] [ 144 ] [ 148 ] It is listed on the World Health Organization's List of Essential Medicines. [ 78 ] In 2022, it was the 127th most commonly prescribed medication in the United States, with over 4 million prescriptions. [ 28 ] [ 149 ]
Insulin detemir is only sold under the name Levemir by Novo Nordisk, who owned its patent until 2019. in certain countries, Levemir and certain related products were discontinued in 2024. [ 150 ]
Insulin glargine is a long-acting modified form of medical insulin used in the management of type 1 and type 2 diabetes. [ 151 ] It is administered through subcutaneous injection. Its effects typically begin within an hour of injection. [ 151 ] [ 152 ]
Common side effects include (hypoglycemia, issues at the injection site, itchiness, and weight gain. [ 151 ] NPH insulin is generally preferred over insulin glargine during pregnancy. [ 153 ] After injection, microcrystals gradually release insulin over a period of approximately 24 hours. [ 151 ] This insulin works by facilitating the absorption of glucose by body tissues and reducing glucose production by the liver. [ 154 ]
Insulin glargine was patented, although the patent expired in most countries in 2014. It was approved for medical use in the United States in 2000. [ 152 ] It is listed on the World Health Organization's List of Essential Medicines. [ 78 ] In 2022, it ranked as the 28th most commonly prescribed medication in the United States, with more than 18 million prescriptions. [ 28 ] [ 155 ] In July 2021, the US Food and Drug Administration (FDA) approved an interchangeable biosimilar insulin product, Semglee (insulin glargine-yfgn), for the treatment of diabetes. [ 156 ] Unbranded versions of insulin glargine and insulin glargine-yfgn are sold by Sanofi [ 157 ] and Viatris. [ 158 ]
Ultralente insulin was a long-acting form of medical insulin, but not a true analogue. It had an onset of 4 to 6 hours, a peak effect between 14 and 24 hours, and a duration of 28 to 36 hours. [ 167 ] In the mid-2000s, ultralente insulin, along with lente insulin, was discontinued in the United States due to decreasing use in favor of NPH insulin and newer insulin products. [ 168 ] By 2011, the U.S. Food and Drug Administration (FDA) had officially withdrawn approval for ultralente insulin products. [ 169 ]
Insulin degludec is an ultralong-acting basal insulin analogue developed by Novo Nordisk. [ 172 ] Ultralong-acting insulins are a kind of insulin that can work up to a week. [ 173 ] It is administered through subcutaneous injection to assist in controlling blood sugar levels in individuals with diabetes. Its duration of action lasts up to 42 hours, which is significantly longer than other long-acting insulins, such as insulin glargine and insulin detemir, which typically last 18 to 26 hours. This makes insulin degludec a once-daily basal insulin, [ 174 ] [ 175 ] [ 176 ] providing a steady insulin level, in contrast to fast-acting bolus insulins.
Insulin degludec is a modified form of insulin in which a single amino acid is deleted compared to human insulin. It is also conjugated to hexadecanedioic acid via a gamma-L-glutamyl spacer at the amino acid lysine at position B29. [ 175 ]
It is included on the World Health Organization's List of Essential Medicines [ 78 ] as an alternative to insulin glargine. In 2022, it was the 138th most commonly prescribed medication in the United States, with more than 4 million prescriptions. [ 28 ] [ 177 ] Insulin Degludec is currently only produced by Novo Nordisk under the name Tresiba. [ 172 ] It is also available under a generic label until the start of 2026. [ 15 ]
Insulin icodec is a medication used to enhance glycemic control in individuals with diabetes. [ 178 ] It is an ultralong-acting basal insulin analogue developed by Novo Nordisk. [ 179 ] The analog has a plasma half-life exceeding eight days, which is significantly longer than the 25-hour half-life of insulin degludec, the previously longest-acting insulin analogue. Insulin icodec functions as a once-weekly basal insulin. [ 178 ]
Structurally, insulin icodec consists of two peptide chains connected by a disulfide bridge, similar to insulin. However, it includes a C20 fatty diacid-containing side chain to enable strong, reversible albumin binding. Additionally, three amino acid substitutions enhance molecular stability, reduce insulin receptor binding, and slow clearance, collectively extending its duration of action. [ 180 ]
Insulin icodec received approval for medical use in Canada in March 2024. [ 179 ] In the same month, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) issued a positive opinion, recommending marketing authorization for insulin icodec. [ 178 ] Subsequently, insulin icodec was approved for medical use in the European Union in May 2024. [ 180 ] Insulin icodec is currently marketed by Novo Nordisk under the name Awiqli (pronounced A-week-ly). [ 181 ]
Insulin mixtures can sometimes be combined in a single syringe, such as when mixing intermediate-acting insulin with rapid- or short-acting insulin. However, not all types of insulin are compatible for mixing. [ 182 ] [ 183 ]
For convenience, there are premixed formulations of rapid- and intermediate-acting insulins. [ 2 ] These come in fixed ratios like 75/25, 70/30, or 50/50. [ 183 ] For example, a 75/25 mix contains 75% intermediate-acting insulin and 25% rapid-acting insulin. [ 182 ] [ 2 ] These are typically injected twice a day at the start of meals. The mixture appears cloudy, and it begins to work as quickly as the rapid-acting insulin, but it lasts as long as the intermediate-acting insulin. [ 182 ]
Insulin glargine/lixisenatide, marketed under the brand name Soliqua, [ 192 ] is a fixed-dose combination medication that combines insulin glargine and lixisenatide for the treatment of diabetes. [ 193 ] The most common side effects include hypoglycemia, diarrhea, vomiting, and nausea . [ 194 ]
Insulin glargine/lixisenatide was approved for medical use in the United States in November 2016, and in the European Union in January 2017. [ 192 ] It is currently only marketed by Sanofi as Soliqua. [ 192 ]
Insulin degludec/liraglutide is a fixed-dose combination medication used to improve glycemic control in adults with type 2 diabetes, alongside diet and exercise. [ 195 ] [ 196 ] [ 197 ] It consists of insulin degludec and liraglutide and is administered through subcutaneous injection. [ 196 ] [ 197 ] Gastrointestinal side effects include nausea, diarrhea, vomiting, constipation, dyspepsia (indigestion), gastritis (stomach inflammation), abdominal pain, flatulence, gastroesophageal reflux disease (acid reflux), and abdominal distension. [ 196 ] [ 197 ] Severe symptomatic hypoglycemia was reported in a small number of patients during clinical trials. [ 197 ]
Insulin degludec functions as a replacement insulin, facilitating glucose uptake into cells and thereby reducing the symptoms and complications of diabetes. [ 196 ] [ 197 ] It differs slightly from human insulin, as it is absorbed more gradually and consistently, allowing for prolonged action. [ 196 ] Liraglutide, a GLP-1 receptor agonist, mimics the effects of incretin hormones by enhancing insulin secretion from the pancreas in response to food intake, thereby aiding blood glucose regulation. [ 198 ]
Insulin degludec/liraglutide is sold by Novo Nordisk under the name Xultophy. [ 199 ]
Insulins that are used mostly in humans are sometimes also used in animals such as cats and dogs. [ 200 ] These include Lantus (insulin glargine), Novolin (NPH insulin), Humulin (NPH insulin), and Levemir (Detemir). [ 201 ] It is of note that one of the listed insulins other than lente and PZI are FDA-approved for use in animals. [ 200 ]
Following the discontinuation of Lente insulin for human use, the FDA approved a veterinary formulation derived from porcine insulin, known as Vetsulin, for daily administration in dogs and twice-daily use in cats. [ 202 ] Insulin analogs developed for human use after Lente insulin's discontinuation have not yet been demonstrated to offer the same benefits and predictability in feline and canine patients. For this reason, along with other considerations, Lente insulin remains a widely used treatment for diabetes in both dogs and cats. [ 203 ]
Lente insulin is currently produced by Merck Animal Health under the name Vetsulin. [ 200 ] [ 202 ]
Protamine zinc insulin (PZI) is the name of a slight variation of NPH insulin that includes zinc, which is similar to lente. [ 204 ] It is used for cats and dogs. [ 205 ] It is manufactured by Boehringer Ingelheim Animal Health under the name ProZinc. [ 200 ] | https://en.wikipedia.org/wiki/List_of_commercially_available_insulins |
Roofing material is the outermost layer on the roof of a building, sometimes self-supporting, but generally supported by an underlying structure. A building's roofing material provides shelter from the natural elements. The outer layer of a roof shows great variation dependent upon availability of material, and the nature of the supporting structure. Those types of roofing material which are commercially available range from natural products such as thatch and slate to commercially produced products such as tiles and polycarbonate sheeting. Roofing materials may be placed on top of a secondary water-resistant material called underlayment.
Steep roof materials are roofs that are only recommended where water can freely and openly drain off the edge of the roof without retaining water for too long. [ 1 ] The aim is to drain off water completely due to the high water permeability of most of these materials, for instance: the Thatched roofs. In areas where the International Build Code or similar is utilized, the minimum slope required is 2:12, though some countries extend this as high as 4:12
Thatch roofing is typically made of plant stalks in overlapping layers.
A shingle is the generic term for an individual roofing unit that is applied with other such units in an overlapping fashion. [ 2 ]
While slates have high cost, they have a life expectancy of 80 to 400 years. See the article slate industry for an overview including names of quarries. Some of the famous quarries where the highest quality slate comes from that are available in Australia are Bethesda in Wales and areas of Spain.
Tile roofing traditionally consists of locally available materials such as clay, granite, terracotta or slate, though many modern applications contain concrete.
Metal roofing is any of a large variety of roof coverings made from metal and is characterized by its high resistance, impermeability, and longevity. While there are an infinite variety of how to produce metal roofing, thicknesses, and types for metal/finishes used, roofing is generally grouped into 2 categories: Exposed Fastener Panels and Hidden Fastener Panels. Exposed Fastener panels are held down by fasteners through the outside of the metal, whereas Hidden Fastener Panels are held by hidden fasteners, clips, and sometimes adhesives. Typical metals include Galvanized Steel, Galvalume, Aluminum, Copper, or Vinyl 9Which while not metal is included in many cases for its matching profiles).
Low slope materials include roofing materials that can be installed at below 2:12 slope, although in the majority of cases low slope materials can also be installed at steeper slopes.
Membrane roofing consists of large sheets, generally fused in some way at the joints to form a continuous surface.
Liquid roofing includes:
Modified bitumen are long rolls of asphalt-based materials, that can be heat-welded, self-adhering asphalt-adhered, or installed with adhesive. Asphalt is mixed with polymers such as APP or SBS, then applied to fiberglass and/or polyester mat, seams sealed by locally melting the asphalt with heat, hot mopping of asphalt, or adhesive. Lends itself well to most applications.
Built-up roofs (BURs) consist of multiple plies of bitumen-coated organic felt, polyester felt, or coated fiberglass felts. Three to five plies of felt are laminated to each other and to the substrate with hot asphalt, coal tar pitch, or made-for-purpose cold adhesive. Although the roof membrane can be left bare, it is typically covered with a thick flood coat of the bituminous adhesive and covered with gravel, mineral granules, or a reflective coating, each of which protects the BUR from ultraviolet (UV) light degradation (UV causes evaporation of tar and oxidation of asphalt). Gravel not only provides UV protection, it also helps accommodate sudden temperature changes (thermal shock), protects the surface from hail and mechanical damage, and increases the weight of the roof system to resist wind blow-off.
Concrete roofing is composed of concrete reinforced with fibers of some sort. | https://en.wikipedia.org/wiki/List_of_commercially_available_roofing_materials |
This is a compilation of symbols commonly used in astronomy, particularly professional astronomy .
Astrometry parameters
Cosmological parameters
Distance description for orbital and non-orbital parameters:
Galaxy type and spectral comparison:
Luminosity comparison:
Luminosity of certain object:
Mass comparison:
Mass of certain object:
Metallicity comparison:
Orbital Parameters of a Cosmic Object:
Radius comparison:
Spectral comparison:
Temperature description: | https://en.wikipedia.org/wiki/List_of_common_astronomy_symbols |
This is a list of some of the most commonly used coordinate transformations .
Let ( x , y ) {\displaystyle (x,y)} be the standard Cartesian coordinates , and ( r , θ ) {\displaystyle (r,\theta )} the standard polar coordinates .
x = r cos θ y = r sin θ ∂ ( x , y ) ∂ ( r , θ ) = [ cos θ − r sin θ sin θ − r cos θ ] Jacobian = det ∂ ( x , y ) ∂ ( r , θ ) = r {\displaystyle {\begin{aligned}x&=r\cos \theta \\y&=r\sin \theta \\[5pt]{\frac {\partial (x,y)}{\partial (r,\theta )}}&={\begin{bmatrix}\cos \theta &-r\sin \theta \\\sin \theta &{\phantom {-}}r\cos \theta \end{bmatrix}}\\[5pt]{\text{Jacobian}}=\det {\frac {\partial (x,y)}{\partial (r,\theta )}}&=r\end{aligned}}}
x = e ρ cos θ , y = e ρ sin θ . {\displaystyle {\begin{aligned}x&=e^{\rho }\cos \theta ,\\y&=e^{\rho }\sin \theta .\end{aligned}}}
By using complex numbers ( x , y ) = x + i y ′ {\displaystyle (x,y)=x+iy'} , the transformation can be written as x + i y = e ρ + i θ {\displaystyle x+iy=e^{\rho +i\theta }}
That is, it is given by the complex exponential function .
x = a sinh τ cosh τ − cos σ y = a sin σ cosh τ − cos σ {\displaystyle {\begin{aligned}x&=a{\frac {\sinh \tau }{\cosh \tau -\cos \sigma }}\\y&=a{\frac {\sin \sigma }{\cosh \tau -\cos \sigma }}\end{aligned}}}
x = 1 4 c ( r 1 2 − r 2 2 ) y = ± 1 4 c 16 c 2 r 1 2 − ( r 1 2 − r 2 2 + 4 c 2 ) 2 {\displaystyle {\begin{aligned}x&={\frac {1}{4c}}\left(r_{1}^{2}-r_{2}^{2}\right)\\[1ex]y&=\pm {\frac {1}{4c}}{\sqrt {16c^{2}r_{1}^{2}-\left(r_{1}^{2}-r_{2}^{2}+4c^{2}\right)^{2}}}\end{aligned}}}
x = ∫ cos [ ∫ κ ( s ) d s ] d s y = ∫ sin [ ∫ κ ( s ) d s ] d s {\displaystyle {\begin{aligned}x&=\int \cos \left[\int \kappa (s)\,ds\right]ds\\y&=\int \sin \left[\int \kappa (s)\,ds\right]ds\end{aligned}}}
r = x 2 + y 2 θ ′ = arctan | y x | {\displaystyle {\begin{aligned}r&={\sqrt {x^{2}+y^{2}}}\\\theta '&=\arctan \left|{\frac {y}{x}}\right|\end{aligned}}} Note: solving for θ ′ {\displaystyle \theta '} returns the resultant angle in the first quadrant ( 0 < θ < π 2 {\textstyle 0<\theta <{\frac {\pi }{2}}} ). To find θ , {\displaystyle \theta ,} one must refer to the original Cartesian coordinate, determine the quadrant in which θ {\displaystyle \theta } lies (for example, (3,−3) [Cartesian] lies in QIV), then use the following to solve for θ : {\displaystyle \theta :}
θ = { θ ′ for θ ′ in QI: 0 < θ ′ < π 2 π − θ ′ for θ ′ in QII: π 2 < θ ′ < π π + θ ′ for θ ′ in QIII: π < θ ′ < 3 π 2 2 π − θ ′ for θ ′ in QIV: 3 π 2 < θ ′ < 2 π {\displaystyle \theta ={\begin{cases}\theta '&{\text{for }}\theta '{\text{ in QI: }}&0<\theta '<{\frac {\pi }{2}}\\[1.2ex]\pi -\theta '&{\text{for }}\theta '{\text{ in QII: }}&{\frac {\pi }{2}}<\theta '<\pi \\[1.2ex]\pi +\theta '&{\text{for }}\theta '{\text{ in QIII: }}&\pi <\theta '<{\frac {3\pi }{2}}\\[1.2ex]2\pi -\theta '&{\text{for }}\theta '{\text{ in QIV: }}&{\frac {3\pi }{2}}<\theta '<2\pi \end{cases}}}
The value for θ {\displaystyle \theta } must be solved for in this manner because for all values of θ {\displaystyle \theta } , tan θ {\displaystyle \tan \theta } is only defined for − π 2 < θ < + π 2 {\textstyle -{\frac {\pi }{2}}<\theta <+{\frac {\pi }{2}}} , and is periodic (with period π {\displaystyle \pi } ). This means that the inverse function will only give values in the domain of the function, but restricted to a single period. Hence, the range of the inverse function is only half a full circle.
Note that one can also use r = x 2 + y 2 θ ′ = 2 arctan y x + r {\displaystyle {\begin{aligned}r&={\sqrt {x^{2}+y^{2}}}\\\theta '&=2\arctan {\frac {y}{x+r}}\end{aligned}}}
r = r 1 2 + r 2 2 − 2 c 2 2 θ = arctan [ 8 c 2 ( r 1 2 + r 2 2 − 2 c 2 ) r 1 2 − r 2 2 − 1 ] {\displaystyle {\begin{aligned}r&={\sqrt {\frac {r_{1}^{2}+r_{2}^{2}-2c^{2}}{2}}}\\\theta &=\arctan \left[{\sqrt {{\frac {8c^{2}(r_{1}^{2}+r_{2}^{2}-2c^{2})}{r_{1}^{2}-r_{2}^{2}}}-1}}\right]\end{aligned}}}
Where 2 c is the distance between the poles.
ρ = log x 2 + y 2 , θ = arctan y x . {\displaystyle {\begin{aligned}\rho &=\log {\sqrt {x^{2}+y^{2}}},\\\theta &=\arctan {\frac {y}{x}}.\end{aligned}}}
κ = x ′ y ″ − y ′ x ″ ( x ′ 2 + y ′ 2 ) 3 2 s = ∫ a t x ′ 2 + y ′ 2 d t {\displaystyle {\begin{aligned}\kappa &={\frac {x'y''-y'x''}{\left({x'}^{2}+{y'}^{2}\right)^{\frac {3}{2}}}}\\s&=\int _{a}^{t}{\sqrt {{x'}^{2}+{y'}^{2}}}\,dt\end{aligned}}}
κ = r 2 + 2 r ′ 2 − r r ″ ( r 2 + r ′ 2 ) 3 2 s = ∫ a φ r 2 + r ′ 2 d φ {\displaystyle {\begin{aligned}\kappa &={\frac {r^{2}+2{r'}^{2}-rr''}{(r^{2}+{r'}^{2})^{\frac {3}{2}}}}\\s&=\int _{a}^{\varphi }{\sqrt {r^{2}+{r'}^{2}}}\,d\varphi \end{aligned}}}
Let (x, y, z) be the standard Cartesian coordinates, and (ρ, θ, φ) the spherical coordinates , with θ the angle measured away from the +Z axis (as [1] , see conventions in spherical coordinates ). As φ has a range of 360° the same considerations as in polar (2 dimensional) coordinates apply whenever an arctangent of it is taken. θ has a range of 180°, running from 0° to 180°, and does not pose any problem when calculated from an arccosine, but beware for an arctangent.
If, in the alternative definition, θ is chosen to run from −90° to +90°, in opposite direction of the earlier definition, it can be found uniquely from an arcsine, but beware of an arccotangent. In this case in all formulas below all arguments in θ should have sine and cosine exchanged, and as derivative also a plus and minus exchanged.
All divisions by zero result in special cases of being directions along one of the main axes and are in practice most easily solved by observation.
x = ρ sin θ cos φ y = ρ sin θ sin φ z = ρ cos θ ∂ ( x , y , z ) ∂ ( ρ , θ , φ ) = ( sin θ cos φ ρ cos θ cos φ − ρ sin θ sin φ sin θ sin φ ρ cos θ sin φ ρ sin θ cos φ cos θ − ρ sin θ 0 ) {\displaystyle {\begin{aligned}x&=\rho \,\sin \theta \cos \varphi \\y&=\rho \,\sin \theta \sin \varphi \\z&=\rho \,\cos \theta \\{\frac {\partial (x,y,z)}{\partial (\rho ,\theta ,\varphi )}}&={\begin{pmatrix}\sin \theta \cos \varphi &\rho \cos \theta \cos \varphi &-\rho \sin \theta \sin \varphi \\\sin \theta \sin \varphi &\rho \cos \theta \sin \varphi &\rho \sin \theta \cos \varphi \\\cos \theta &-\rho \sin \theta &0\end{pmatrix}}\end{aligned}}}
So for the volume element : d x d y d z = det ∂ ( x , y , z ) ∂ ( ρ , θ , φ ) d ρ d θ d φ = ρ 2 sin θ d ρ d θ d φ {\displaystyle dx\,dy\,dz=\det {\frac {\partial (x,y,z)}{\partial (\rho ,\theta ,\varphi )}}\,d\rho \,d\theta \,d\varphi =\rho ^{2}\sin \theta \,d\rho \,d\theta \,d\varphi }
x = r cos θ y = r sin θ z = z ∂ ( x , y , z ) ∂ ( r , θ , z ) = ( cos θ − r sin θ 0 sin θ r cos θ 0 0 0 1 ) {\displaystyle {\begin{aligned}x&=r\,\cos \theta \\y&=r\,\sin \theta \\z&=z\,\\{\frac {\partial (x,y,z)}{\partial (r,\theta ,z)}}&={\begin{pmatrix}\cos \theta &-r\sin \theta &0\\\sin \theta &r\cos \theta &0\\0&0&1\end{pmatrix}}\end{aligned}}}
So for the volume element: d V = d x d y d z = det ∂ ( x , y , z ) ∂ ( r , θ , z ) d r d θ d z = r d r d θ d z {\displaystyle dV=dx\,dy\,dz=\det {\frac {\partial (x,y,z)}{\partial (r,\theta ,z)}}\,dr\,d\theta \,dz=r\,dr\,d\theta \,dz}
ρ = x 2 + y 2 + z 2 θ = arctan ( x 2 + y 2 z ) = arccos ( z x 2 + y 2 + z 2 ) φ = arctan ( y x ) = arccos ( x x 2 + y 2 ) = arcsin ( y x 2 + y 2 ) ∂ ( ρ , θ , φ ) ∂ ( x , y , z ) = ( x ρ y ρ z ρ x z ρ 2 x 2 + y 2 y z ρ 2 x 2 + y 2 − x 2 + y 2 ρ 2 − y x 2 + y 2 x x 2 + y 2 0 ) {\displaystyle {\begin{aligned}\rho &={\sqrt {x^{2}+y^{2}+z^{2}}}\\\theta &=\arctan \left({\frac {\sqrt {x^{2}+y^{2}}}{z}}\right)=\arccos \left({\frac {z}{\sqrt {x^{2}+y^{2}+z^{2}}}}\right)\\\varphi &=\arctan \left({\frac {y}{x}}\right)=\arccos \left({\frac {x}{\sqrt {x^{2}+y^{2}}}}\right)=\arcsin \left({\frac {y}{\sqrt {x^{2}+y^{2}}}}\right)\\{\frac {\partial \left(\rho ,\theta ,\varphi \right)}{\partial \left(x,y,z\right)}}&={\begin{pmatrix}{\frac {x}{\rho }}&{\frac {y}{\rho }}&{\frac {z}{\rho }}\\{\frac {xz}{\rho ^{2}{\sqrt {x^{2}+y^{2}}}}}&{\frac {yz}{\rho ^{2}{\sqrt {x^{2}+y^{2}}}}}&-{\frac {\sqrt {x^{2}+y^{2}}}{\rho ^{2}}}\\{\frac {-y}{x^{2}+y^{2}}}&{\frac {x}{x^{2}+y^{2}}}&0\\\end{pmatrix}}\end{aligned}}}
See also the article on atan2 for how to elegantly handle some edge cases.
So for the element: d ρ d θ d φ = det ∂ ( ρ , θ , φ ) ∂ ( x , y , z ) d x d y d z = 1 x 2 + y 2 x 2 + y 2 + z 2 d x d y d z {\displaystyle d\rho \,d\theta \,d\varphi =\det {\frac {\partial (\rho ,\theta ,\varphi )}{\partial (x,y,z)}}\,dx\,dy\,dz={\frac {1}{{\sqrt {x^{2}+y^{2}}}{\sqrt {x^{2}+y^{2}+z^{2}}}}}\,dx\,dy\,dz}
ρ = r 2 + h 2 θ = arctan r h φ = φ ∂ ( ρ , θ , φ ) ∂ ( r , h , φ ) = ( r r 2 + h 2 h r 2 + h 2 0 h r 2 + h 2 − r r 2 + h 2 0 0 0 1 ) det ∂ ( ρ , θ , φ ) ∂ ( r , h , φ ) = 1 r 2 + h 2 {\displaystyle {\begin{aligned}\rho &={\sqrt {r^{2}+h^{2}}}\\\theta &=\arctan {\frac {r}{h}}\\\varphi &=\varphi \\{\frac {\partial (\rho ,\theta ,\varphi )}{\partial (r,h,\varphi )}}&={\begin{pmatrix}{\frac {r}{\sqrt {r^{2}+h^{2}}}}&{\frac {h}{\sqrt {r^{2}+h^{2}}}}&0\\{\frac {h}{r^{2}+h^{2}}}&{\frac {-r}{r^{2}+h^{2}}}&0\\0&0&1\\\end{pmatrix}}\\\det {\frac {\partial (\rho ,\theta ,\varphi )}{\partial (r,h,\varphi )}}&={\frac {1}{\sqrt {r^{2}+h^{2}}}}\end{aligned}}}
r = x 2 + y 2 θ = arctan ( y x ) z = z {\displaystyle {\begin{aligned}r&={\sqrt {x^{2}+y^{2}}}\\\theta &=\arctan {\left({\frac {y}{x}}\right)}\\z&=z\quad \end{aligned}}}
∂ ( r , θ , h ) ∂ ( x , y , z ) = ( x x 2 + y 2 y x 2 + y 2 0 − y x 2 + y 2 x x 2 + y 2 0 0 0 1 ) {\displaystyle {\frac {\partial (r,\theta ,h)}{\partial (x,y,z)}}={\begin{pmatrix}{\frac {x}{\sqrt {x^{2}+y^{2}}}}&{\frac {y}{\sqrt {x^{2}+y^{2}}}}&0\\{\frac {-y}{x^{2}+y^{2}}}&{\frac {x}{x^{2}+y^{2}}}&0\\0&0&1\end{pmatrix}}}
r = ρ sin φ h = ρ cos φ θ = θ ∂ ( r , h , θ ) ∂ ( ρ , φ , θ ) = ( sin φ ρ cos φ 0 cos φ − ρ sin φ 0 0 0 1 ) det ∂ ( r , h , θ ) ∂ ( ρ , φ , θ ) = − ρ {\displaystyle {\begin{aligned}r&=\rho \sin \varphi \\h&=\rho \cos \varphi \\\theta &=\theta \\{\frac {\partial (r,h,\theta )}{\partial (\rho ,\varphi ,\theta )}}&={\begin{pmatrix}\sin \varphi &\rho \cos \varphi &0\\\cos \varphi &-\rho \sin \varphi &0\\0&0&1\\\end{pmatrix}}\\\det {\frac {\partial (r,h,\theta )}{\partial (\rho ,\varphi ,\theta )}}&=-\rho \end{aligned}}}
s = ∫ 0 t x ′ 2 + y ′ 2 + z ′ 2 d t κ = ( z ″ y ′ − y ″ z ′ ) 2 + ( x ″ z ′ − z ″ x ′ ) 2 + ( y ″ x ′ − x ″ y ′ ) 2 ( x ′ 2 + y ′ 2 + z ′ 2 ) 3 2 τ = x ‴ ( y ′ z ″ − y ″ z ′ ) + y ‴ ( x ″ z ′ − x ′ z ″ ) + z ‴ ( x ′ y ″ − x ″ y ′ ) ( x ′ y ″ − x ″ y ′ ) 2 + ( x ″ z ′ − x ′ z ″ ) 2 + ( y ′ z ″ − y ″ z ′ ) 2 {\displaystyle {\begin{aligned}s&=\int _{0}^{t}{\sqrt {{x'}^{2}+{y'}^{2}+{z'}^{2}}}\,dt\\[3pt]\kappa &={\frac {\sqrt {\left(z''y'-y''z'\right)^{2}+\left(x''z'-z''x'\right)^{2}+\left(y''x'-x''y'\right)^{2}}}{\left({x'}^{2}+{y'}^{2}+{z'}^{2}\right)^{\frac {3}{2}}}}\\[3pt]\tau &={\frac {x'''\left(y'z''-y''z'\right)+y'''\left(x''z'-x'z''\right)+z'''\left(x'y''-x''y'\right)}{{\left(x'y''-x''y'\right)}^{2}+{\left(x''z'-x'z''\right)}^{2}+{\left(y'z''-y''z'\right)}^{2}}}\end{aligned}}} | https://en.wikipedia.org/wiki/List_of_common_coordinate_transformations |
This is a list of common household pests – undesired animals that have a history of living, invading, causing damage, eating human foods, acting as disease vectors or causing other harms in human habitation. | https://en.wikipedia.org/wiki/List_of_common_household_pests |
Commutative algebra is the branch of abstract algebra that studies commutative rings , their ideals , and modules over such rings. Both algebraic geometry and algebraic number theory build on commutative algebra. Prominent examples of commutative rings include polynomial rings , rings of algebraic integers , including the ordinary integers Z {\displaystyle \mathbb {Z} } , and p-adic integers . | https://en.wikipedia.org/wiki/List_of_commutative_algebra_topics |
This article lists the companies worldwide engaged in the development of quantum computing, quantum communication and quantum sensing . Quantum computing and communication are two sub-fields of quantum information science , which describes and theorizes information science in terms of quantum physics . While the fundamental unit of classical information is the bit , the basic unit of quantum information is the qubit . Quantum sensing is the third main sub-field of quantum technologies and it focus consists in taking advantage of the quantum states sensitivity to the surrounding environment to perform atomic scale measurements.
Computing/Communication
Quantum Hardware
Quantum Algorithms
Quantum Computing Software
Universitat de Barcelona ( UB )
Barcelona Supercomputing Center ( BSC )
Quantum Algorithms
Quantum Random Number Generator
Quantum Hardware
Computing
Crypto accelerators, High Performance Computing
Orquestra Quantum Operating Environment [ 116 ] | https://en.wikipedia.org/wiki/List_of_companies_involved_in_quantum_computing,_communication_or_sensing |
This page is intended to list all current compilers , compiler generators, interpreters , translators, tool foundations, assemblers , automatable command line interfaces ( shells ), etc.
cf. ALGOL 68s specification and implementation timeline
Notes:
Notes:
This list is incomplete. A more extensive list of source-to-source compilers can be found here .
Production quality, free/libre and open source compilers.
Research compilers are mostly not robust or complete enough to handle real, large applications. They are used mostly for fast prototyping new language features and new optimizations in research areas. | https://en.wikipedia.org/wiki/List_of_compilers |
Compounds are organized into the following lists:
Relevant links for chemical compounds are: | https://en.wikipedia.org/wiki/List_of_compounds |
This is a partial list of molecules that contain 1 carbon atom .
Each hydrogen added to a molecule can be considered as a proton plus a one-electron reduction of the redox state, while each oxygen counts as a two-electron oxidation. Thus a net addition of H 2 O is a simple hydration with no net change in redox state and frequently occurs reversibly in aqueous solution. These relationships may be viewed in the following table ( peroxides and ions are excluded; unstable or hypothetical compounds are italicized). | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_1 |
This is a partial list of molecules that contain 10 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_10 |
This is a partial list of molecules that contain 11 carbon atoms.
methylenedioxymethamphetamine | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_11 |
This is a partial list of molecules that contain 12 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_12 |
This is a partial list of molecules that contain 13 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_13 |
This is a partial list of molecules that contain 14 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_14 |
This is a partial list of molecules that contain 15 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_15 |
This is a partial list of molecules that contain 16 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_16 |
This is a partial list of molecules that contain 17 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_17 |
This is a partial list of molecules that contain 18 carbon atoms . | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_18 |
This is a partial list of molecules that contain 19 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_19 |
This is a partial list of molecules that contain 2 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_2 |
This is a partial list of molecules that contain 20 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_20 |
This is a partial list of molecules that contain 21 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_21 |
This is a partial list of molecules that contain 22 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_22 |
This is a partial list of molecules that contain 23 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_23 |
This is a partial list of molecules that contain 24 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_24 |
This is a partial list of molecules that contain 3 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_3 |
This is a partial list of molecules that contain 4 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_4 |
This is a partial list of molecules that contain 5 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_5 |
This is a partial list of molecules that contain 6 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_6 |
This is a partial list of molecules that contain 7 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_7 |
This is a partial list of molecules that contain 8 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_8 |
This is a partial list of molecules that contain 9 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_number_9 |
This is a partial list of molecules that contain 25 to 29 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_numbers_25–29 |
This is a partial list of molecules that contain 30 to 39 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_numbers_30–39 |
This is a partial list of molecules that contain 40 to 49 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_numbers_40–49 |
This is a partial list of molecules that contain at least 50 carbon atoms. | https://en.wikipedia.org/wiki/List_of_compounds_with_carbon_numbers_50+ |
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