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The Joback method , often named Joback–Reid method , predicts eleven important and commonly used pure component thermodynamic properties from molecular structure only. It is named after Kevin G. Joback in 1984 [ 1 ] and developed it further with Robert C. Reid. [ 2 ] The Joback method is an extension of the Lydersen method [ 3 ] and uses very similar groups, formulas, and parameters for the three properties the Lydersen already supported ( critical temperature , critical pressure , critical volume).
Joback and Reid extended the range of supported properties, created new parameters and modified slightly the formulas of the old Lydersen method.
The Joback method is a group-contribution method . These kinds of methods use basic structural information of a chemical molecule, like a list of simple functional groups, add parameters to these functional groups, and calculate thermophysical and transport properties as a function of the sum of group parameters.
Joback assumes that there are no interactions between the groups, and therefore only uses additive contributions and no contributions for interactions between groups. Other group-contribution methods, especially methods like UNIFAC , which estimate mixture properties like activity coefficients, use both simple additive group parameters and group-interaction parameters. The big advantage of using only simple group parameters is the small number of needed parameters. The number of needed group-interaction parameters gets very high for an increasing number of groups (1 for two groups, 3 for three groups, 6 for four groups, 45 for ten groups and twice as much if the interactions are not symmetric).
Nine of the properties are single temperature-independent values, mostly estimated by a simple sum of group contribution plus an addend.
Two of the estimated properties are temperature-dependent: the ideal-gas heat capacity and the dynamic viscosity of liquids. The heat-capacity polynomial uses 4 parameters, and the viscosity equation only 2. In both cases the equation parameters are calculated by group contributions.
The popularity and success of the Joback method mainly originates from the single group list for all properties. This allows one to get all eleven supported properties from a single analysis of the molecular structure.
The Joback method additionally uses a very simple and easy to assign group scheme, which makes the method usable for people with only basic chemical knowledge.
Newer developments of estimation methods [ 4 ] [ 5 ] have shown that the quality of the Joback method is limited. The original authors already stated themselves in the original article abstract: "High accuracy is not claimed, but the proposed methods are often as or more accurate than techniques in common use today."
The list of groups does not cover many common molecules sufficiently. Especially aromatic compounds are not differentiated from normal ring-containing components. This is a severe problem because aromatic and aliphatic components differ strongly.
The data base Joback and Reid used for obtaining the group parameters was rather small and covered only a limited number of different molecules. The best coverage has been achieved for normal boiling points (438 components), and the worst for heats of fusion (155 components). Current developments that can use data banks, like the Dortmund Data Bank or the DIPPR data base, have a much broader coverage.
The formula used for the prediction of the normal boiling point shows another problem. Joback assumed a constant contribution of added groups in homologous series like the alkanes . This doesn't describe the real behavior of the normal boiling points correctly. [ 6 ] Instead of the constant contribution, a decrease of the contribution with increasing number of groups must be applied. The chosen formula of the Joback method leads to high deviations for large and small molecules and an acceptable good estimation only for mid-sized components.
In the following formulas G i denotes a group contribution. G i are counted for every single available group. If a group is present multiple times, each occurrence is counted separately.
T b [ K ] = 198.2 + ∑ T b , i . {\displaystyle T_{\text{b}}[{\text{K}}]=198.2+\sum T_{{\text{b}},i}.}
T m [ K ] = 122.5 + ∑ T m , i . {\displaystyle T_{\text{m}}[{\text{K}}]=122.5+\sum T_{{\text{m}},i}.}
T c [ K ] = T b [ 0.584 + 0.965 ∑ T c , i − ( ∑ T c , i ) 2 ] − 1 . {\displaystyle T_{\text{c}}[{\text{K}}]=T_{\text{b}}\left[0.584+0.965\sum T_{{\text{c}},i}-\left(\sum T_{{\text{c}},i}\right)^{2}\right]^{-1}.}
This critical-temperature equation needs a normal boiling point T b . If an experimental value is available, it is recommended to use this boiling point. It is, on the other hand, also possible to input the normal boiling point estimated by the Joback method. This will lead to a higher error.
P c [ bar ] = [ 0.113 + 0.0032 N a − ∑ P c , i ] − 2 , {\displaystyle P_{\text{c}}[{\text{bar}}]=\left[0.113+0.0032\,N_{\text{a}}-\sum P_{{\text{c}},i}\right]^{-2},}
where N a is the number of atoms in the molecular structure (including hydrogens).
V c [ cm 3 / mol ] = 17.5 + ∑ V c , i . {\displaystyle V_{\text{c}}[{\text{cm}}^{3}/{\text{mol}}]=17.5+\sum V_{{\text{c}},i}.}
H formation [ kJ / mol ] = 68.29 + ∑ H form , i . {\displaystyle H_{\text{formation}}[{\text{kJ}}/{\text{mol}}]=68.29+\sum H_{{\text{form}},i}.}
G formation [ kJ / mol ] = 53.88 + ∑ G form , i . {\displaystyle G_{\text{formation}}[{\text{kJ}}/{\text{mol}}]=53.88+\sum G_{{\text{form}},i}.}
C P [ J / ( mol ⋅ K ) ] = ∑ a i − 37.93 + [ ∑ b i + 0.210 ] T + [ ∑ c i − 3.91 ⋅ 10 − 4 ] T 2 + [ ∑ d i + 2.06 ⋅ 10 − 7 ] T 3 . {\displaystyle C_{P}[{\text{J}}/({\text{mol}}\cdot {\text{K}})]=\sum a_{i}-37.93+\left[\sum b_{i}+0.210\right]T+\left[\sum c_{i}-3.91\cdot 10^{-4}\right]T^{2}+\left[\sum d_{i}+2.06\cdot 10^{-7}\right]T^{3}.}
The Joback method uses a four-parameter polynomial to describe the temperature dependency of the ideal-gas heat capacity. These parameters are valid from 273 K to about 1000 K. But you are able to extend it to 1500K if you don't mind a bit of uncertainty here and there.
Δ H vap [ kJ / mol ] = 15.30 + ∑ H vap , i . {\displaystyle \Delta H_{\text{vap}}[{\text{kJ}}/{\text{mol}}]=15.30+\sum H_{{\text{vap}},i}.}
Δ H fus [ kJ / mol ] = − 0.88 + ∑ H fus , i . {\displaystyle \Delta H_{\text{fus}}[{\text{kJ}}/{\text{mol}}]=-0.88+\sum H_{{\text{fus}},i}.}
η L [ Pa ⋅ s ] = M w e x p [ ( ∑ η a − 597.82 ) / T + ∑ η b − 11.202 ] , {\displaystyle \eta _{\text{L}}[{\text{Pa}}\cdot {\text{s}}]=M_{\text{w}}exp{\left[\left(\sum \eta _{a}-597.82\right)/T+\sum \eta _{b}-11.202\right]},}
where M w is the molecular weight .
The method uses a two-parameter equation to describe the temperature dependency of the dynamic viscosity. The authors state that the parameters are valid from the melting temperature up to 0.7 of the critical temperature ( T r < 0.7).
Acetone (propanone) is the simplest ketone and is separated into three groups in the Joback method: two methyl groups (−CH 3 ) and one ketone group (C=O). Since the methyl group is present twice, its contributions have to be added twice. | https://en.wikipedia.org/wiki/Joback_method |
The Jobar sarin attack took place on 24 August 2013 around 11:00 in Jobar , a suburb of the Syrian capital city Damascus .
Jobar is a suburb of Syria 's capital city Damascus . The suburb is located approximately 3 kilometers (1.9 mi) northeast of the Damascus city center.
On 24 August 2013, a group of Syrian Army soldiers were clearing buildings from opposition forces in Jobar. Around 11:00, the intensity of the shooting from the opposition side subsided and the soldiers believed the rebels were retreating. Then, an improvised explosive device detonated with a low noise about 10 meters from them. The IED reportedly released "a very badly smelling gas". [ 1 ] : 15, 16
10 soldiers were injured and evacuated to the nearest medical point where they were treated with intravenous fluids and oxygen before being sent to Martyr Yusuf Al Azmah Military Hospital for further treatment. Four of them were severely affected. Another 20 soldiers came later with similar symptoms, but they were in stable condition and could, after some time, be sent back to their units. [ 1 ] : 15–17, 61–70 All patients received "atropine, HI-6, steroids, oxygen therapy and fluids treatment." [ 1 ] : 67
The UN mission received soil samples from the impact site and remnants of two IEDs allegedly used to disperse the chemical agent. The soil samples tested positive for sarin . However, the UN mission "could not verify the chain of custody for this sampling and subsequent analysis". [ 1 ] : 16, 65 On 30 August 2013, the UN mission visited the affected soldiers at a military hospital. [ 2 ] | https://en.wikipedia.org/wiki/Jobar_sarin_attack |
In organic chemistry , the Jocic reaction , also called the Jocic–Reeve reaction (named after Zivojin Jocic [ 1 ] and Wilkins Reeve [ 2 ] ) is a name reaction that generates α-substituted carboxylic acids from trichloromethylcarbinols and corresponding nucleophiles in the presence of sodium hydroxide . The reaction involves nucleophilic displacement of the hydroxyl group in a 1,1,1-trichloro-2-hydroxyalkyl structure with concomitant conversion of the trichloromethyl portion to a carboxylic acid or other acyl group .
The key stages of the reaction involve an S N 2 reaction , where the nucleophile displaces the oxygen with geometric inversion .
The reaction mechanism involves an epoxide intermediate that undergoes an S N 2 reaction by the nucleophile. As a result of this mechanistic aspect, the reaction can easily occur on secondary or tertiary positions, and chiral products can be made by using chiral alcohol substrates. [ 3 ] [ 4 ] The reaction is one stage of the Corey–Link reaction , the Bargellini reaction , and other processes for synthesizing α- amino acids and related structures. Using hydride as the nucleophile, which also reduces the carbonyl of the product, allows this sequence to be used as a homologation reaction for primary alcohols . [ 5 ]
Examples of this reaction include: Generation of α-azidocarboxylic acids with the use of sodium azide as the nucleophile in DME with the presence of sodium hydroxide. [ 6 ] Conversion of aldehydes to homoelongated carboxylic acids, by first reacting with trichloromethide to form a trichloromethylcarbinol, then undergoing a Jocic reaction with either sodium borohydride or sodium phenylseleno(triethoxy)borate as the nucleophile in sodium hydroxide. [ 7 ] This reaction can be followed by the introduction of an amine , to form the corresponding homoelongated amides. [ 8 ] | https://en.wikipedia.org/wiki/Jocic_reaction |
In organic chemistry , the Jocic reaction , also called the Jocic–Reeve reaction (named after Zivojin Jocic [ 1 ] and Wilkins Reeve [ 2 ] ) is a name reaction that generates α-substituted carboxylic acids from trichloromethylcarbinols and corresponding nucleophiles in the presence of sodium hydroxide . The reaction involves nucleophilic displacement of the hydroxyl group in a 1,1,1-trichloro-2-hydroxyalkyl structure with concomitant conversion of the trichloromethyl portion to a carboxylic acid or other acyl group .
The key stages of the reaction involve an S N 2 reaction , where the nucleophile displaces the oxygen with geometric inversion .
The reaction mechanism involves an epoxide intermediate that undergoes an S N 2 reaction by the nucleophile. As a result of this mechanistic aspect, the reaction can easily occur on secondary or tertiary positions, and chiral products can be made by using chiral alcohol substrates. [ 3 ] [ 4 ] The reaction is one stage of the Corey–Link reaction , the Bargellini reaction , and other processes for synthesizing α- amino acids and related structures. Using hydride as the nucleophile, which also reduces the carbonyl of the product, allows this sequence to be used as a homologation reaction for primary alcohols . [ 5 ]
Examples of this reaction include: Generation of α-azidocarboxylic acids with the use of sodium azide as the nucleophile in DME with the presence of sodium hydroxide. [ 6 ] Conversion of aldehydes to homoelongated carboxylic acids, by first reacting with trichloromethide to form a trichloromethylcarbinol, then undergoing a Jocic reaction with either sodium borohydride or sodium phenylseleno(triethoxy)borate as the nucleophile in sodium hydroxide. [ 7 ] This reaction can be followed by the introduction of an amine , to form the corresponding homoelongated amides. [ 8 ] | https://en.wikipedia.org/wiki/Jocic–Reeve_reaction |
Joel Lexchin is a professor emeritus at the York University Faculty of Health where he taught about pharmaceutical policy , an Associate Professor in the Department of Family and Community Medicine at the University of Toronto , an emergency physician at the Toronto General Hospital and a Fellow in the Canadian Academy of Health Sciences . [ 1 ] [ 2 ] [ 3 ] Lexchin is the author of over 160 peer-reviewed publications. [ 3 ] [ 4 ]
Lexchin received his MD from the University of Toronto in 1977. [ 1 ]
From 1992 for two years Lexchin was a member of the Ontario Drug Quality and Therapeutics Committee. He was the chair of the Drugs and Pharmacotherapy Committee of the Ontario Medical Association from 1997 for two years. [ 1 ]
In 2013, he was quoted in a learned article on Drug patents: the evergreening problem , [ 5 ] and he wrote the article on the pharmaceutical industry for the Canadian Encyclopedia . [ 6 ]
Lexchin is frequently critical of Canada 's drug regulator, the Health Products and Food Branch , [ 7 ] [ 8 ] as has been noticed in the learned press. [ 9 ]
In 2006, Lexchin was quoted by Manzer: "Drug approvals are not all science. There’s always decisions to be made around how much risk are we willing to take in terms of drugs, and I think as the industry takes on a larger role in funding the regulatory bodies that those kinds of decisions tend to be made more in favour of the drug companies," [ 10 ] and in 2010 was noticed in a Toronto Star article entitled "Health Canada keeps some drug studies secret". [ 11 ] | https://en.wikipedia.org/wiki/Joel_Lexchin |
A jog dial , jog wheel , shuttle dial , or shuttle wheel is a type of knob, ring, wheel, or dial which allows the user to shuttle or jog through audio or video media. It is commonly found on models of CD players which are made for disc jockeys , and on professional video equipment such as video tape recorders . [ 1 ] More recently, they are found on handheld PDAs , and as the scroll wheel on computer mice . "Jog" refers to going at a very slow speed, whereas "shuttle" refers to a very fast speed.
There are two basic types of wheels. One type has no stops and can be spun the entire way around, because it is a rotary incremental encoder . [ 2 ] This type depends on tracking the actual motion of the dial: the faster it spins forward or back, the faster it fast-forwards or rewinds. Once the dial stops moving, the media continues playing or remains paused at that point. Another type has stops on either side, and often has three or so speeds which depend on how far it is turned. Once the wheel is released, it springs back to the middle position and the media pauses or begins playing again.
If the device is set or designed to pause after the wheel is used, the audio is often stuttered , repeating a small section over and over again. This is usually done on DJ CD players, for the purpose of beatmatching , and is equivalent to an earlier turntablist DJ moving a phonograph record back and forth slightly to find the physical location of a starting beat within the groove. On the video, the pause is a freeze frame of the current video frame .
Sony Corporation holds a patent [ 3 ] for a 5-way version of the jog dial. A 5-way jog dial allows up and down scrolling, right and left deflections, and a press-to-click action. Such jog dial was a feature of the Sony CLIÉ PDA series and Sony Ericsson P800 , P900 and P910 smartphones. A 5-way jog dial has not been used by Sony or its subsidiaries since 2006. | https://en.wikipedia.org/wiki/Jog_dial |
Johan Antony Barrau (3 April 1873, Oisterwijk – 8 January 1953, Utrecht) was a Dutch mathematician, specializing in geometry. [ 1 ]
Barrau was educated at the Dutch Royal Naval College at Willemsoord and then at the University of Amsterdam . From 1891 to 1898, Barrau was an officer with the Royal Netherlands Navy , later with the Netherlands Marine Corps . However, he left the service and became a mathematics teacher at a Hogere Burgerschool in Dordrecht until 1900, then in Amsterdam. [ 1 ] In 1907 he obtained his PhD at the University of Amsterdam under the supervision of Diederik Korteweg . [ 2 ] From 1908 to 1913 Barrau was a mathematics professor at the Delft University of Technology . He was a professor of synthetic, analytical and descriptive differential geometry at the University of Groningen from 1913 to 1928. [ 1 ] From 1928 until his retirement at age 70, he was a professor at Utrecht University . [ 3 ] He received the military service medal consisting of the Expedition Cross with the Atjeh clasp and was named Knight of the Order of the Netherlands Lion . Barrau published a textbook on analytical geometry and various articles in national and international journals. [ 1 ]
He was an Invited Speaker of the ICM in 1920 at Strasbourg [ 4 ] and in 1924 at Toronto. [ 5 ] | https://en.wikipedia.org/wiki/Johan_Antony_Barrau |
Johann Bernoulli [ a ] (also known as Jean in French or John in English; 6 August [ O.S. 27 July] 1667 – 1 January 1748) was a Swiss mathematician and was one of the many prominent mathematicians in the Bernoulli family . He is known for his contributions to infinitesimal calculus and educating Leonhard Euler in the pupil's youth.
Johann was born in Basel , the son of Nicolaus Bernoulli, an apothecary , and his wife, Margarethe Schongauer, and began studying medicine at University of Basel . His father desired that he study business so that he might take over the family spice trade, but Johann Bernoulli did not like business and convinced his father to allow him to study medicine instead. Johann Bernoulli began studying mathematics on the side with his older brother Jacob Bernoulli . [ 5 ] Throughout Johann Bernoulli's education at Basel University , the Bernoulli brothers worked together, spending much of their time studying the newly discovered infinitesimal calculus. They were among the first mathematicians to not only study and understand calculus but to apply it to various problems. [ 6 ] In 1690, [ 7 ] he completed a degree dissertation in medicine, [ 8 ] reviewed by Gottfried Leibniz , [ 7 ] whose title was De Motu musculorum et de effervescent et fermentation . [ 9 ]
After graduating from Basel University, Johann Bernoulli moved to teach differential equations . Later, in 1694, he married Dorothea Falkner, the daughter of an alderman of Basel, and soon after accepted a position as the professor of mathematics at the University of Groningen . At the request of his father-in-law , Bernoulli began the voyage back to his home town of Basel in 1705. Just after setting out on the journey he learned of his brother's death to tuberculosis . Bernoulli had planned on becoming the professor of Greek at Basel University upon returning but instead was able to take over as professor of mathematics, his older brother's former position. As a student of Leibniz 's calculus, Bernoulli sided with him in 1713 in the Leibniz–Newton debate over who deserved credit for the discovery of calculus. Bernoulli defended Leibniz by showing that he had solved certain problems with his methods that Newton had failed to solve. Bernoulli also promoted Descartes ' vortex theory over Newton's theory of gravitation . This ultimately delayed acceptance of Newton's theory in continental Europe . [ 10 ]
In 1724, Johann Bernoulli entered a competition sponsored by the French Académie Royale des Sciences , which posed the question:
In defending a view previously espoused by Leibniz, he found himself postulating an infinite external force required to make the body elastic by overcoming the infinite internal force making the body hard. In consequence, he was disqualified for the prize, which was won by Maclaurin . However, Bernoulli's paper was subsequently accepted in 1726 when the Académie considered papers regarding elastic bodies, for which the prize was awarded to Pierre Mazière. Bernoulli received an honourable mention in both competitions.
Although Johann and his brother Jacob Bernoulli worked together before Johann graduated from Basel University, shortly after this, the two developed a jealous and competitive relationship. Johann was jealous of Jacob's position and the two often attempted to outdo each other. After Jacob's death, Johann's jealousy shifted toward his own talented son, Daniel . In 1738 the father–son duo nearly simultaneously published separate works on hydrodynamics (Daniel's Hydrodynamica in 1738 and Johann's Hydraulica in 1743). Johann attempted to take precedence over his son by purposely and falsely predating his work six years prior to his son's. [ 11 ] [ 12 ]
The Bernoulli brothers often worked on the same problems, but not without friction. Their most bitter dispute concerned the brachistochrone curve problem, or the equation for the path followed by a particle from one point to another in the shortest amount of time, if the particle is acted upon by gravity alone. Johann presented the problem in 1696, offering a reward for its solution. Entering the challenge, Johann proposed the cycloid, the path of a point on a moving wheel, also pointing out the relation this curve bears to the path taken by a ray of light passing through layers of varied density. Jacob proposed the same solution, but Johann's derivation of the solution was incorrect, and he presented his brother Jacob's derivation as his own. [ 13 ]
Bernoulli was hired by Guillaume de l'Hôpital for tutoring in mathematics. Bernoulli and l'Hôpital signed a contract which gave l'Hôpital the right to use Bernoulli's discoveries as he pleased. L'Hôpital authored the first textbook on infinitesimal calculus, Analyse des Infiniment Petits pour l'Intelligence des Lignes Courbes in 1696, which mainly consisted of the work of Bernoulli, including what is now known as l'Hôpital's rule . [ 14 ] [ 15 ] [ 16 ] Subsequently, in letters to Leibniz, Pierre Varignon and others, Bernoulli complained that he had not received enough credit for his contributions, in spite of the preface of his book:
I recognize I owe much to the insights of the Messrs. Bernoulli, especially to those of the younger (John), currently a professor in Groningen. I did unceremoniously use their discoveries, as well as those of Mr. Leibniz. For this reason I consent that they claim as much credit as they please, and will content myself with what they will agree to leave me. | https://en.wikipedia.org/wiki/Johann_Bernoulli |
Johannes Trolle Hjelmslev ( Danish: [ˈjelˀmsle̝w] ; 7 April 1873 – 16 February 1950) was a mathematician from Hørning , Denmark . Hjelmslev worked in geometry and history of geometry . He was the discoverer and eponym of the Hjelmslev transformation , a method for mapping an entire hyperbolic plane into a circle with a finite radius .
He was the father of Louis Hjelmslev .
Originally named Johannes Trolle Petersen, he changed his patronymic to the surname Hjelmslev to avoid confusion with Julius Petersen . Some of his results are known under his original name, including the Petersen–Morley theorem . [ 1 ] | https://en.wikipedia.org/wiki/Johannes_Hjelmslev |
Johannes Widmann (c. 1460 – after 1498) was a German mathematician . The + and - symbols first appeared in print in his book Mercantile Arithmetic or Behende und hüpsche Rechenung auff allen Kauffmanschafft published in Leipzig in 1489 in reference to surpluses and deficits in business problems. [ 1 ]
Born in Eger , Bohemia , Widmann attended the University of Leipzig in the 1480s. In 1482 he earned his " Baccalaureus " (Bachelor of Art degree) and in 1485 his " Magister " (doctorate).
Widman published Behende und hübsche Rechenung auff allen Kauffmanschafft ( German ; i.e. Nimble and neat calculation in all trades), his work making use of the signs, in Leipzig in 1489. [ 1 ] Further editions were published in Pforzheim , Hagenau , and Augsburg .
Handwritten entries in a surviving collection show that after earning his "Magister" Widman announced holding lectures on e.g. calculating on the lines of a calculating board and on algebra. There is evidence that the lecture on algebra actually took place, making it the first known university lecture on this topic. [ citation needed ]
Around 1495 Widmann published the Latin writings Algorithmus integrorum cum probis annexis , Algorithmus linealis , Algorithmus minutiarum phisicarum , Algorithmus minutiarum vulgarium , Regula falsi apud philosophantes augmenti et decrementi appellata und Tractatus proportionum plusquam aureus .
He died in Leipzig .
When Adam Ries was in Erfurt between 1518 and 1522 he got to know Widmann's algebra lecture script (today in the Saxon State Library) wherefrom he took examples for his own writings.
This article about a German mathematician is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Johannes_Widmann |
Johannes Wislicenus ( German pronunciation: [joˈhanəs vɪsliˈt͜seːnʊs] ; 24 June 1835 – 5 December 1902) was a German chemist , most famous for his work in early stereochemistry .
The son of the radical Protestant theologian Gustav Wislicenus , [ 1 ] Johannes was born on 24 June 1835 in Kleineichstedt (now part of Querfurt , Saxony-Anhalt ) in Prussian Saxony , and entered University of Halle-Wittenberg in 1853. [ 2 ] In October 1853 he immigrated to the United States with his family. For a brief time he acted as assistant to Harvard chemist Eben Horsford , and in 1855 was appointed lecturer at the Mechanics' Institute in New York. Returning to Europe in 1856, he continued to study chemistry with Wilhelm Heinrich Heintz at the University of Halle. In 1860, he began lecturing at the University of Zürich , and at the Swiss Polytechnical Institute and by 1868 he was Professor of Chemistry at the university. In 1870, he was chosen to succeed Georg Staedeler as Professor of General Chemistry at the Swiss Polytechnical Institute in Zürich, retaining also the position of full professor at the University of Zürich. In 1872, he succeeded Adolph Strecker in the chair of chemistry at University of Würzburg , and in 1885, he succeeded Hermann Kolbe as Professor of Chemistry at the University of Leipzig , where he died on 6 December 1902. [ 2 ]
By the late 1860s, [ citation needed ] Wislicenus devoted his research to organic chemistry. [ 2 ] His work on the isomeric lactic acids from 1868 to 1872 [ 3 ] resulted in the discovery of two substances with different physical properties but with an identical chemical structure . [ 2 ] He called this difference "geometrical isomerism". [ 2 ] He would later promote J. H. van't Hoff 's theory of the tetrahedral carbon atom, believing that it, together with the supposition that there are "specially directed forces, the affinity-energies", [ 2 ] which determine the relative position of atoms in the molecule , afforded a method by which the spatial arrangement of atoms in particular cases may be ascertained by experiment. While at Würzburg, Wislicenus developed the use of ethyl aceto acetate in organic synthesis. [ 2 ] However, he was also active in inorganic chemistry, finding a reaction for the production of sodium azide . He was the first to prepare cyclopentane in 1893 [ 4 ]
In 1898 Wislicenus was awarded the Davy Medal by the Royal Society of London . [ 2 ] | https://en.wikipedia.org/wiki/Johannes_Wislicenus |
Johari–Goldstein relaxation , also known as the JG β -relaxation , is a universal property of glasses and certain other disordered materials.
Proposed in 1969 [ 1 ] by Martin Goldstein, JG β -relaxation were described as a secondary relaxation mechanism required to explain the viscosity behavior of liquids approaching the glass transition in the potential energy landscape picture presented in Goldstein's seminal 1969 paper. Previous experiments on glass forming liquids showed multiple relaxation times present in liquids measured by time dependent compliance measurements. [ 2 ] Gyan Johari and Martin Goldstein [ 3 ] measured the dielectric loss spectrum of a set of rigid glass forming molecules to further test the hypothesis of Goldstein in 1969. The relaxation, a peak in mechanical or dielectric loss at a particular frequency, had previously been attributed to a type of molecular flexibility. [ citation needed ] The fact that such a loss peak shows up in glasses of rigid molecules lacking this flexibility demonstrated its universal character.
The JG β -relaxation process is speculated to be a precursor of the structural α-relaxation, [ 4 ] [ 5 ] i.e., its occurrence facilitates viscous flow, however the microscopic mechanism of the β -relaxation has not been definitively identified. [ 6 ]
Johari determined the temperature dependence of the α-relaxation and β -relaxation as a function of frequency by measuring the dielectric loss ε″ as a function of frequency at multiple temperatures. [ 7 ] They observed two peaks in the system with the lower frequency peak attributed to the structural α-relaxation and the higher frequency peak related to the fast (high frequency short time) β -relaxation. The peak in the high frequency ε″ response of the β -relaxation has also been shown to broaden and shift to lower frequencies. Furthermore, the α-relaxation peak changes more rapidly on cooling than the rate of JG β -relaxation, where the α-relaxation times diverge following the VFT law as glass transition temperature (Tg) is approached which is much faster than the Arrhenius temperature dependence observed for the peak in the β -relaxation curve over the same temperature ranges. [ 7 ]
The J.G. β -relaxation was developed based on the theoretical predictions of Martin Goldstein in his seminal 1969 paper discussing the potential energy landscape picture and activated energy barrier hopping for viscous liquids. [ 1 ] These developments have often focused on understanding secondary relaxations below Tg that are present in small molecule and metallic glasses. Polymer glasses also show multiple relaxation mechanisms at temperatures below Tg, with β , γ , and δ relaxations having been measured well below Tg into the glassy state. [ 8 ] However, the exact molecular mechanism for these relaxations is often subject to debate and how they may relate to J. G β -relaxations is not established by the literature. | https://en.wikipedia.org/wiki/Johari–Goldstein_relaxation |
The Academy of Motion Picture Arts and Sciences awards the John A. Bonner Medal of Commendation upon the recommendation of its Scientific and Technical Awards Committee. The medal is awarded with a citation reading "in appreciation for outstanding service and dedication in upholding the high standards of the Academy." The inaugural Medal of Commendation was given at the 50th Academy Awards in April 1978, and is given irregularly. [ 1 ]
The medal was originally called the Medal of Commendation but was named in 1997 for the American sound engineer John A. Bonner who served for several years as the governor of the academy's Sound Branch; and as chair of its Scientific and Technical Awards Committee and its Theater Sound Inspection Committee. [ 1 ] Bonner had also been the director of special projects at Warner-Hollywood Studios . The president of the Academy of Motion Picture Arts and Sciences , Arthur Hiller said that no person "...better represents the concept of service and dedication to the Academy" than Bonner and that he was "...dedicated to the Academy for more than 30 years. His devotion to the Academy's Samuel Goldwyn Theater was legendary and his commitment to the Academy was simply extraordinary." [ 1 ] | https://en.wikipedia.org/wiki/John_A._Bonner_Medal_of_Commendation |
John Bannister Goodenough ( / ˈ ɡ ʊ d ɪ n ʌ f / GUUD -in-uf ; July 25, 1922 – June 25, 2023) was an American materials scientist, a solid-state physicist , and a Nobel laureate in chemistry . From 1986 he was a professor of Materials Science, Electrical Engineering and Mechanical Engineering, [ 3 ] at the University of Texas at Austin . He is credited with
identifying the Goodenough–Kanamori rules of the sign of the magnetic superexchange in materials, with developing materials for computer random-access memory and with inventing cathode materials for lithium-ion batteries .
Goodenough was awarded the National Medal of Science , the Copley Medal , the Fermi Award , the Draper Prize , and the Japan Prize . The John B. Goodenough Award in materials science is named for him. In 2019, he was awarded the Nobel Prize in Chemistry alongside M. Stanley Whittingham and Akira Yoshino ; at 97 years old, he became the oldest Nobel laureate in history. [ 4 ] From August 27, 2021, until his death, he was the oldest living Nobel Prize laureate.
John Goodenough was born in Jena, Germany , on July 25, 1922, [ 5 ] to American parents, Erwin Ramsdell Goodenough (1893–1965) and Helen Miriam (Lewis) Goodenough. [ 6 ] He came from an academic family. His father, a graduate student at Oxford when John was born, eventually became a professor of religious history at Yale . [ 7 ] [ 8 ] His brother Ward became an anthropology professor at the University of Pennsylvania . [ 9 ] John also had two half-siblings from his father's second marriage: Ursula Goodenough , emeritus professor of biology at Washington University in St. Louis ; and Daniel Goodenough, emeritus professor of biology at Harvard Medical School . [ 10 ]
In his school years Goodenough suffered from dyslexia . At the time, dyslexia was poorly understood by the medical community, and Goodenough's condition went undiagnosed and untreated. [ 10 ] Although his primary schools considered him "a backward student," he taught himself to write so that he could take the entrance exam for Groton School , the boarding school where his older brother was studying at the time. [ 10 ] [ 11 ] He was awarded a full scholarship. [ 7 ] At Groton, his grades improved and he eventually graduated at the top of his class in 1940. [ 10 ] [ 12 ] He also developed an interest in exploring nature, plants, and animals. [ 13 ] Although he was raised an atheist, he converted to Protestant Christianity in high school. [ 11 ] [ 14 ] [ 15 ]
After Groton, Goodenough graduated summa cum laude from Yale , where he was a member of Skull and Bones . [ 16 ] He completed his coursework in early 1943 (after just two and a half years) and received his degree in 1944, [ 17 ] covering his expenses by tutoring and grading exams. [ 16 ] He had initially sought to enlist in the military following the Japanese attack on Pearl Harbor , but his mathematics professor convinced him to stay at Yale for another year so that he could finish his coursework, which qualified him to join the U.S. Army Air Corps' meteorology department. [ 11 ] [ 16 ]
After World War II ended, Goodenough obtained a master's degree and a Ph.D. in physics from the University of Chicago , the latter in 1952. [ 11 ] [ 18 ] His doctoral supervisor was Clarence Zener , a theorist in electrical breakdown ; he also worked and studied with physicists, including Enrico Fermi and John A. Simpson . While at Chicago, he met Canadian history graduate student Irene Wiseman. [ 19 ] [ 20 ] They married in 1951. [ 10 ] [ 7 ] The couple had no children. [ 10 ] Irene died in 2016. [ 20 ]
Goodenough turned 100 on July 25, 2022. [ 21 ] He died at an assisted living facility in Austin, Texas , on June 25, 2023, one month shy of what would have been his 101st birthday. [ 22 ] [ 23 ] [ 10 ]
Over his career, Goodenough authored more than 550 articles, 85 book chapters and reviews, and five books, including two seminal works, Magnetism and the Chemical Bond (1963) [ 24 ] and Les oxydes des metaux de transition (1973). [ 25 ]
After his studies, Goodenough was a research scientist and team leader at the MIT Lincoln Laboratory for 24 years. At MIT, he was part of an interdisciplinary team responsible for developing random access magnetic memory . [ 26 ] His research focused on magnetism and on the metal–insulator transition behavior in transition-metal oxides . His research efforts on RAM led him to develop the concepts of cooperative orbital ordering, also known as a cooperative Jahn–Teller distortion , in oxide materials. [ 27 ] They subsequently led him to develop (with Junjiro Kanamori ) the Goodenough–Kanamori rules , a set of semi-empirical rules to predict the sign of the magnetic superexchange in materials; superexchange is a core property for high-temperature superconductivity . [ 28 ] [ 29 ] [ 30 ]
The U.S. government eventually terminated Goodenough's research funding, so during the late 1970s and early 1980s, he left the United States and continued his career as head of the Inorganic Chemistry Laboratory at the University of Oxford . [ 27 ] Among the highlights of his work at Oxford, Goodenough is credited with significant research essential to the development of commercial lithium-ion rechargeable batteries . [ 27 ] Goodenough was able to expand upon previous work from M. Stanley Whittingham on battery materials, and found in 1980 that by using Li x CoO 2 as a lightweight, high energy density cathode material, he could double the capacity of lithium-ion batteries.
Although Goodenough saw a commercial potential of batteries with his LiCoO2 and LiNiO2 cathodes and approached the University of Oxford with a request to patent this invention, it refused. Unable to afford the patenting expenses with his academic salary, Goodenough turned to UK's Atomic Energy Research Establishment in Harwell , which accepted his offer, but under the terms, which provided zero royalty payment to the inventors John B. Goodenough and Koichi Mizushima . In 1990, the AERE licensed Goodenough's patents to Sony Corporation , which was followed by other battery manufacturers. It was estimated, that the AERE made over 10 mln. British pounds from this licensing. [ citation needed ]
The work at Sony on further improvements to Goodenough's invention was led by Akira Yoshino , who had developed a scaled up design of the battery and manufacturing process. [ 31 ] Goodenough received the Japan Prize in 2001 for his discoveries of the materials critical to the development of lightweight high energy density rechargeable lithium batteries, [ 32 ] and he, Whittingham, and Yoshino shared the 2019 Nobel Prize in Chemistry for their research in lithium-ion batteries. [ 31 ]
From 1986, Goodenough was a professor at The University of Texas at Austin in the Cockrell School of Engineering departments of Mechanical Engineering and Electrical Engineering . [ 33 ] During his tenure there, he continued his research on ionic conducting solids and electrochemical devices; he continued to study improved materials for batteries, aiming to promote the development of electric vehicles and to help reduce human dependency on fossil fuels . [ 34 ] Arumugam Manthiram and Goodenough discovered the polyanion class of cathodes. [ 35 ] [ 36 ] [ 37 ] They showed that positive electrodes containing polyanions , e.g., sulfates , produce higher voltages than oxides due to the inductive effect of the polyanion. The polyanion class includes materials such as lithium-iron phosphates that are used for smaller devices like power tools. [ 38 ] His group also identified various promising electrode and electrolyte materials for solid oxide fuel cells. [ 25 ] He held the Virginia H. Cockrell Centennial Chair in Engineering. [ 39 ]
Goodenough still worked at the university at age 98 as of 2021, [ 40 ] hoping to find another breakthrough in battery technology. [ 41 ] [ 42 ]
On February 28, 2017, Goodenough and his team at the University of Texas published a paper in the journal Energy and Environmental Science on their demonstration of a glass battery , a low-cost all-solid-state battery that is noncombustible and has a long cycle life with a high volumetric energy density , and fast rates of charge and discharge. Instead of liquid electrolytes, the battery uses glass electrolytes that enable the use of an alkali -metal anode without the formation of dendrites . [ 43 ] [ 42 ] [ 44 ] However, this paper was met with widespread skepticism by the battery research community and remains controversial after several follow-up works. The work was criticized for a lack of comprehensive data, [ 45 ] spurious interpretations of the data obtained, [ 45 ] and that the proposed mechanism of battery operation would violate the first law of thermodynamics . [ 46 ]
In April 2020, a patent was filed for the glass battery on behalf of Portugal's National Laboratory of Energy and Geology (LNEG), the University of Porto , Portugal, and the University of Texas. [ 47 ]
In 2010, Goodenough joined the technical advisory board of Enevate, a silicon-dominant Li-ion battery technology startup based in Irvine, California . [ 48 ] Goodenough also served as an adviser to the Joint Center for Energy Storage Research (JCESR) , a collaboration led by Argonne National Laboratory and funded by the Department of Energy . [ 49 ] From 2016, Goodenough also worked as an adviser for Battery500, a national consortium led by Pacific Northwest National Laboratory (PNNL) and partially funded by the U.S. Department of Energy . [ 50 ] [ 51 ]
Goodenough was elected a member of the National Academy of Engineering in 1976 for his work designing materials for electronic components and clarifying the relationships between the properties, structures, and chemistry of substances. He was also a member of the American National Academy of Sciences and its French , Spanish , and Indian counterparts. [ 52 ] In 2010, he was elected a Foreign Member of the Royal Society . [ 53 ] The Royal Society of Chemistry grants a John B. Goodenough Award in his honor. [ 27 ] The Electrochemical Society awards a biannual John B. Goodenough Award of The Electrochemical Society . [ 54 ]
Goodenough received the following awards:
Goodenough was 97 when he received the Nobel Prize. He remains the oldest person ever to have been awarded the prize. | https://en.wikipedia.org/wiki/John_B._Goodenough |
John Brass was a manager and later director of Houghton Main Colliery Co Ltd. According to the Colliery Year Book and Coal Trades Directory he was "one of the most prominent figures in the South Yorkshire coal mining industry". [ 1 ] He held significant posts in the mining, gas and coke industries both in South Yorkshire and nationally. Between 1934 and 1937 he was one of the assessors in the Gresford disaster inquiry and, along with the other assessor, published dissenting reports to the main inquiry.
Brass' father Thomas Francis Brass OBE, JP, MA(Durham) was born in 1858, the son of a blacksmith in Sherburn Hill , County Durham. [ 2 ] TF Brass rose from colliery clerk through colliery cashier, to become a Surface Manager and eventually the Under Manager for Kimblesworth Colliery. By 1921 he was the agent (responsible for the general laying out and supervision of the workings) for Charlaw & Sacriston Collieries Co Ltd. [ 2 ] In 1903 he was one of the team of rescuers who entered the flooded Sacriston pit. For this he was awarded the silver medal of the Royal Humane Society . TF Brass retired in 1934 and died in 1937. [ 2 ]
Brass was born 1879 in Wingate, County Durham. [ 3 ] He was the eldest son of Thomas Francis Brass, the agent for Charlaw & Sacriston Collieries Co Ltd. Brass attended the Royal Grammar School, Newcastle upon Tyne . In 1894 he started work at Charlaw & Sacriston Collieries in County Durham. In 1902 he gained his Manager's certificate (number 2,098) and in 1903 became the manager or Primrose Colliery. In that year he was one of the rescuers who entered Sacriston Colliery along with his father. For this action he was awarded The Royal Humane Society's silver medal.<Royal Humane Society citation><Messrs. Spinks medal sale 19 November 2015> The Colliery Year Book and Coal Trades Directory for 1940 credits him with the medal, but the issues for 1933, 1945 and 1950 do not. [ 3 ] The Mines Inspectors Report for 1903 states that: "six of the explorers ; those selected being Mr. W. Walker, Inspector of Mines, Mr. W. C. Blackett, the Agent of the Colliery, Mr. S. Tate, the Agent for Messrs. Walter Scott, Ltd., Mr. T. F. Brass, Assistant Manager, and H. Blackburn and J. Hall, two Deputy-Overmen." [ 4 ] By 1909 he was a member of the Institute of Mining Engineers.
During the First World War he was Acting Major, 13th York and Lancaster Service Battalion. [ 3 ] [ a ] Later in the war Brass was appointed Divisional Commander of Special Police for the Staincross Division of Yorkshire and became a Military Representative on Tribunals. [ 3 ]
In 1923 Brass was Director and General Manager of Houghton Main Colliery Co Ltd. Between 1923 and 1925 he was the President of the Midland Institute of Mining Engineers during which time he also became a member of the Institution of Civil Engineers . [ 3 ] In 1929 Brass was a member of the committee which examined the issues surrounding the replacement of rail mounted tubs with conveyor belts. [ 6 ]
In 1935 he was awarded the Medal of the Institution of Mining Engineers "in recognition of distinguished services to the mining profession and industry over a period of many years". [ 7 ] He was also awarded the Peake Gold Medal by the Midland Institute of Mining Engineers. [ 3 ]
On Saturday 22 September 1934 at 2:08 a.m. a violent explosion ripped through the Dennis section of Gresford Colliery . [ 8 ] An inquiry into the Gresford disaster was ordered on 11 October 1934 and sat intermittently from 25 October 1934 to 13 December 1936. [ 8 ] The report was laid before Parliament and debated on 23 February 1937. [ 9 ] The inquiry sat with a commissioner and two assessors, one of whom was Brass. The outcome was unusual for all three men arrived at different conclusions with the assessors' reports being presented as appendices to the main report. [ 8 ] The official finding, as presented by the commissioner Sir Henry Walker, viewed with suspicion shot firing activities. The other assessor, Mr Joseph Jones , was concerned about a possible firedamp build up on one of the faces which was ignited by an accident with a safety lamp or from a spark from a mechanised coalcutter. Brass however was concerned about the telephones which were not of an approved type. He surmised that the explosion could have been caused by a gas build on one of the main access tunnels which was ignited by the telephone being called. [ 8 ] | https://en.wikipedia.org/wiki/John_Brass_(colliery_manager) |
John Casey (12 May 1820, Kilbehenny , County Limerick , Ireland – 3 January 1891, Dublin ) was a respected Irish geometer . He is most famous for Casey's theorem on a circle that is tangent to four other circles, an extension of Ptolemy's theorem . However, he contributed several novel proofs and perspectives on Euclidean geometry . He and Émile Lemoine are considered to be the co-founders of the modern geometry of the circle and the triangle. [ 1 ]
He was born at Kilbehenny in Limerick, Ireland and educated locally at Mitchelstown, before becoming a teacher under the Board of National Education. He later became headmaster of the Central Model Schools in Kilkenny City . He subsequently entered Trinity College Dublin in 1858, where he was elected a Scholar in 1861 and was awarded the degree of BA in 1862. He was then Mathematics Master at Kingston School (1862–1873), Professor of Higher Mathematics and Mathematical Physics at the newly founded Catholic University of Ireland (1873–1881) and Lecturer in Mathematics at its successor, the University College Dublin (1881–1891). [ 2 ]
In 1869, the University of Dublin awarded Casey the Honorary Degree of Doctor of Laws. He was elected a Fellow of the Royal Society in June 1875. [ 3 ] He was elected to the Royal Irish Academy and in 1880 became a member of its council. In 1878 the Academy conferred upon him the much coveted Cunningham Gold Medal. [ 4 ] His work was also acknowledged by the Norwegian Government, among others. He was elected a member of the Societe Mathematique de France in 1884 and received the honorary degree of Doctor of Laws from the Royal University of Ireland in 1885. | https://en.wikipedia.org/wiki/John_Casey_(mathematician) |
John Dudley Corbett (March 23, 1926 – September 2, 2013) was an American chemist who specialized in inorganic solid-state chemistry . At Iowa State and Ames Lab, Corbett lead a research group that focused on the synthesis and characterization of two broad classes of materials, notably Zintl phases [ 1 ] and condensed transition metal halide clusters. [ 2 ] [ 3 ] [ 4 ] Both classes of materials are important for their uses, for instance thermoelectrics , and for the theoretical advances they made possible by working to understand their complex bonding and electronic properties. [ 5 ] [ 6 ]
After graduating from Yakima High School , serving in the United States Navy until the end of World War II , and attending the North Dakota Teachers College , the University of Wisconsin–Madison , and the University of Washington , Corbett remained at Washington to complete his Ph.D. in 1952. [ 7 ] [ 8 ] He joined the chemistry faculty of Iowa State University and the scientific staff of Ames Laboratory in 1953. He was affiliated with both institutions for his entire career, and served as chair of the Department of Chemistry between 1968 and 1973. [ 9 ] He was elected a Fellow of the American Association for the Advancement of Science . He was awarded two DOE Awards for Outstanding Scientific Accomplishments and Sustained Research in Materials Chemistry, the Humboldt Prize (1985), the 2005 Spedding Award from the Rare Earth Research Conference, [ 10 ] the 2008 Monie A. Ferst Award from Sigma Xi , and several ACS Awards for both Inorganic Chemistry and Distinguished Service in the Advancement of Inorganic Chemistry. [ 11 ] He was elected to the United States National Academy of Sciences in 1992. [ 12 ] [ 13 ]
Corbett was born to parents Alexander and Elizabeth Corbett in Yakima, Washington , on March 23, 1926, and had two brothers. He was married to F. Irene Lienkaemper from 1948 until her death in 1996. [ 14 ] The couple raised three children. Corbett died on September 2, 2013, at the age of 87, following a stroke. [ 11 ] [ 7 ] The John D. Corbett Professorship was established in 2007, within Iowa State University's Department of Chemistry. [ 11 ] [ 15 ] | https://en.wikipedia.org/wiki/John_Corbett_(chemist) |
Sir John Warcup Cornforth Jr. , [ 3 ] AC , CBE , FRS , FAA (7 September 1917 – 8 December 2013) was an Australian–British chemist who won the Nobel Prize in Chemistry in 1975 for his work on the stereochemistry of enzyme - catalysed reactions, [ 4 ] [ 5 ] becoming the only Nobel laureate born in New South Wales . [ 2 ] [ 6 ] [ 7 ]
Cornforth investigated enzymes that catalyse changes in organic compounds, the substrates, by taking the place of hydrogen atoms in a substrate's chains and rings. In his syntheses and descriptions of the structure of various terpenes , olefins , and steroids , Cornforth determined specifically which cluster of hydrogen atoms in a substrate were replaced by an enzyme to effect a given change in the substrate, allowing him to detail the biosynthesis of cholesterol . [ 8 ] For this work, he won a share of the Nobel Prize in Chemistry in 1975, alongside co-recipient Vladimir Prelog , and was knighted in 1977. [ 9 ]
Born in Sydney, Cornforth was the son and the second of four children of English-born, Oxford -educated schoolmaster and teacher John Warcup Cornforth and Hilda Eipper (1887–1969), a granddaughter of pioneering missionary and Presbyterian minister Christopher Eipper . Before her marriage, Eipper had been a maternity nurse. [ 3 ] [ 10 ]
Cornforth was raised in Sydney as well as Armidale , in the north of New South Wales, [ 11 ] where he undertook primary school education. [ 10 ]
At about 10 years old, [ 12 ] Cornforth had noted signs of deafness, which led to a diagnosis of otosclerosis , a disease of the middle ear which causes progressive hearing loss. This left him completely deaf by the age of 20 but also fatefully influenced his career direction away from law, his original intended field of study, and towards chemistry. [ 13 ] [ 14 ] In an interview with Sir Harry Kroto for the Vega Science Trust , Cornforth explained:
I had to find something in which the loss of hearing would not be too severe a handicap...I chose chemistry...The most liberating thing was the realization that the literature wasn't entirely correct. It gave me quite a shock at first, and then a thrill. Because I can set this right! And always, and ever since, I've relied upon the primary literature exclusively. [ 15 ]
Cornforth was educated at Sydney Boys' High School , where he excelled academically, passed tests in English , mathematics , science , French , Greek , and Latin , [ 16 ] and was inspired by his chemistry teacher, Leonard ("Len") Basser, [ 17 ] [ 18 ] to change his career directions from law to chemistry. [ 12 ] [ 19 ] Cornforth graduated as the dux of the class of 1933 at Sydney Boys' High School, at the age of 16. [ 20 ]
In 1934, Cornforth matriculated and studied at the University of Sydney , [ 20 ] [ 21 ] where he studied organic chemistry at the University of Sydney's School of Chemistry and from which he graduated with a Bachelor of Science with First-Class Honours and the University Medal in 1937. [ 9 ] [ 22 ] During his studies, his hearing became progressively worse, thus making listening to lectures difficult. [ 23 ] At the time, he could not use hearing aids as the sound became distorted, and he did not significantly use lip reading . [ citation needed ]
While studying at the University of Sydney, Cornforth met his future wife, fellow chemist and scientific collaborator, Rita Harradence . [ 24 ] [ 25 ] Harradence was a graduate of St George Girls High School [ 24 ] [ 25 ] and a distinguished academic achiever [ 10 ] [ 26 ] [ 27 ] who had topped the state in Chemistry in the New South Wales Leaving Certificate Examination. [ 28 ] Harradence graduated with a Bachelor of Science with First-Class Honours and the University Medal in Organic Chemistry in 1936, a year ahead of Cornforth. [ 29 ] Harradence also graduated with a MSc in 1937, [ 30 ] writing a master's thesis titled "Attempts to synthesise the pyridine analogue of vitamin B1". [ 31 ]
In 1939, Cornforth and Harradence, independently of each other, each won one of two Science Research Scholarships (the 1851 Research Fellowship ) from the Royal Commission for the Exhibition of 1851 , [ 32 ] tenable overseas for two years. [ 29 ] At the University of Oxford, Harradence was a member of Somerville College while Cornforth was at St. Catherine's College [ 33 ] and they worked with Sir Robert Robinson , with whom they collaborated for 14 years. [ 10 ] During his time at Oxford, Cornforth found working for and with Robinson stimulating, and the two often deliberated to no end until one had a cogent case against the other's counterargument. [ 34 ] In 1941, Cornforth and Harradence both graduated with a D.Phil. in Organic Chemistry. [ 35 ] [ 36 ] At the time, there were no institutions or facilities at which a PhD in chemistry could be done in Australia. [ 37 ]
After his arrival at Oxford and during World War II , Cornforth significantly influenced the work on penicillin , particularly in purifying and concentrating it. Penicillin is usually very unstable in its crude form; as a consequence of this, researchers at the time were building upon Howard Florey 's work on the drug. In 1940, Cornforth and other chemists measured the yield of penicillin in arbitrary units to understand the conditions that favoured penicillin production and activity, and he contributed to the writing of The Chemistry of Penicillin . [ 38 ]
In 1946, the Cornforths, who had by now married, left Oxford and joined the Medical Research Council (MRC), working at the National Institute for Medical Research (NIMR), where they continued on earlier work in synthesising sterols, including cholesterol. The Cornforths' collaboration with Robinson continued and flourished. In 1951, they completed, simultaneously with Robert Burns Woodward [ citation needed ] , the first total synthesis of the non-aromatic steroids. At the NIMR, Cornforth collaborated with numerous biological scientists, including George Popják , [ 39 ] with whom he shared an interest in cholesterol. Together, they received the Davy Medal in 1968 in recognition of their distinguished joint work on the elucidation of the biosynthetic pathway to polyisoprenoids and steroids.
While working at the MRC, Cornforth was appointed a professor at the University of Warwick and was employed there from 1965 to 1971. [ 40 ]
In 1975, Cornforth was awarded a share of the Nobel Prize in Chemistry, alongside Vladimir Prelog . In his acceptance speech, Cornforth said:
Throughout my scientific career my wife has been my most constant collaborator. Her experimental skill made major contributions to the work; she has eased for me beyond measure the difficulties of communication that accompany deafness; her encouragement and fortitude have been my strongest support. [ 41 ]
Also in 1975, he moved to the University of Sussex in Brighton as a Royal Society Research Professor . [ 11 ] [ 42 ] Cornforth remained there as a professor and was active in research until his death. [ 43 ] [ 44 ]
In 1941, the year in which they graduated from the University of Oxford, Cornforth married Rita Harriet Harradence (b. 1915), [ 5 ] [ 24 ] [ 45 ] with whom he had one son, John, and two daughters, Brenda and Philippa. [ 3 ] [ 46 ] Cornforth had met Harradence after she had broken a Claisen flask in their second year at the University of Sydney; Cornforth, with his expertise of glassblowing and the use of a blowpipe , mended the break. [ 47 ] Rita Cornforth died on 6 November 2012, [ 48 ] at home with her family around her, [ 49 ] following a long illness. [ 50 ]
On an important author or paper that was integral to his success, Cornforth stated that he was particularly impressed by the works of German chemist Hermann Emil Fischer . [ 47 ]
Cornforth died in Sussex on 8 December 2013. [ 46 ] [ 51 ] [ 52 ] [ 53 ] at the age of 96. [ 54 ] Cornforth is survived by his three children and four grandchildren. [ 55 ] He was a sceptic and an atheist . [ 56 ]
Cornforth was named the Australian of the Year in 1975, [ 57 ] jointly with Maj. Gen. Alan Stretton . [ 58 ] In 1977, Cornforth was recognised by his alma mater, the University of Sydney, with the award of an honorary Doctor of Science . [ 59 ] [ 60 ] Cornforth's other awards and recognitions follow:
Cornforth's certificate of election for the Royal Society reads:
Distinguished as an Organic Chemist of outstanding originality and exceptional experimental skill, particularly in microchemical manipulation. He was the first to attribute the correct constitution to penicillamine and to synthesise the amino-acid. After making significant contributions to the synthesis of penicillin he notably developed the chemistry of the oxazole group and made oxazole itself for the first time.
The important share he took in the total synthesis of androgenic hormones and other steroids is gratefully recognised by all his collaborators in the investigation.
Miscellaneous work on natural products and chemotherapy equally displays individual thought, invention, and superlative technical accomplishment. [ 1 ]
Cornforth was the focus of a skit on an episode of Comedy Inc . , whereby a fictional Who Wants to Be A Millionaire? contestant (played by Genevieve Morris ) is asked "Which Australian scientist won the Nobel Prize for Chemistry in 1975?" for the million-dollar question. As it happens, the contestant gleefully claims they are second cousins with Cornforth (despite being nearly 50 years his junior) and knows Cornforth is the answer, confidently rattling off a bunch of highly specific and esoteric facts about Cornforth's life and achievements, all the while the host (a satirical portrayal of Eddie McGuire ) stubbornly and continuously stalls her for dramatic effect, asking her for several minutes if she'd like to think about it more to an absurd degree. [ 65 ]
On September 7, 2017, Google celebrated his 100th birthday with a Google Doodle . [ 66 ]
The Royal Australian Chemical Institute (RACI) honours Cornforth by naming its prize for the best PhD thesis in chemical science completed at an Australian university the Cornforth Medal. [ 67 ] | https://en.wikipedia.org/wiki/John_Cornforth |
John Douglas Eshelby FRS (21 December 1916 – 10 December 1981) was a scientist in micromechanics . He made significant contributions to the fields of defect mechanics and micromechanics of inhomogeneous solids for fifty years, including important aspects of the controlling mechanisms of plastic deformation and fracture.
Eshelby was born at Puddington, Cheshire , the son of Captain Alan Douglas Eshelby and Phoebe Mason Hutchinson. He was educated at St Cyprian's School , Eastbourne and was due to go to Charterhouse School but developed rheumatic fever and received his secondary education privately at home. At about this time the family moved to Manor House at Farrington Gurney , Somerset where his tutors were the village schoolmaster and a local clergyman. He relied extensively on self-instruction and obtained a place in the Physics Department of Bristol University and was awarded a first class honours in physics in 1937. He then worked in a research laboratory under H W B Skinner and W Sucksmith on magnetism and the soft X-ray spectra of solids. [ 1 ]
In World War II Eshelby began working for the Admiralty on the degaussing of ships, but on 4 May 1940 he joined the Technical Branch of the Royal Air Force . His work from February 1941 to June 1942 was for the Coastal Command Development Unit conducting performance trials of air-to-surface-vessel radar and other operational devices in all types of aircraft. He was then involved in radar work, from August 1942 to February 1943 with 76 signals wing and from February 1943 to September 1944 at the radar establishment at Malvern. He was then transferred to disarmament work and then to the Air Historical branch in September 1945. He left the RAF as a squadron leader on 4 October 1946. [ 1 ]
After the war Eshelby returned to Bristol University to study for a PhD and taught himself the theory of elasticity for his thesis on "Stationary and moving dislocations". He obtained his PhD in 1950 under Nevill Mott . In 1951 he moved to the University of Illinois Urbana-Champaign as a Research Associate, where he stayed until 1953 when he was appointed a lecturer at the University of Birmingham , [ 1 ] [ 2 ] where he taught from 1953 to 1964 at the Department of Metallurgy. During this time, he worked on point defects and dislocations, developing the method of 'transformation strains' and studying the Eshelby inclusion problems for the first time, as well as the study of forces on elastic singularities. [ 1 ] [ 2 ]
In 1964 he moved to the Cavendish Laboratory at Cambridge University at the behest of Neville Mott, and was a Fellow of Churchill College from 1965 to 1966. He was then appointed Reader in the Faculty of Materials (Theory of Materials) at the University of Sheffield , where he became Professor in 1971. [ 1 ]
Eshelby was clear and amusing as a lecturer, and prepared his lectures with great care, but was not keen on doing experimental work. He was well versed in Sanskrit (among other classical languages) and was an avid second-hand book buyer. [ 1 ]
Eshelby died on 10 December 1981. [ 1 ]
Eshelby was elected a Fellow of the Royal Society in March 1974. He was awarded the Timoshenko Medal in 1977. [ 2 ] [ 1 ]
In 2012, the Eshelby Mechanics Award for Young Faculty and the Eshelby Memorial Bursary was founded in his memory. was launched to commemorate the memory of Eshelby. The award is given annually to rapidly emerging junior faculty who exemplify the creative use and development of mechanics, and awardees are formally recognised at the annual Applied Mechanics Division Banquet at the American Society of Mechanical Engineers ' International Mechanical Engineering Congress and Exposition (ASME-IMECE) meeting. [ 3 ]
Eshelby work helped shape the fields of defect mechanics and micromechanics of inhomogeneous solids for fifty years, including the controlling mechanisms of plastic deformation and fracture.The scientific phenomenon called Eshelby's inclusion is named after this scientist, and points at an ellipsoidal subdomain in an infinite homogeneous body, subjected to a uniform transformation strain. [ 4 ] [ 5 ]
Bilby, B. A. (1990). John Douglas Eshelby. 21 December 1916-10 December 1981 . Biographical Memoirs of Fellows of the Royal Society. 36: 127–150. ISSN 0080-4606 . | https://en.wikipedia.org/wiki/John_D._Eshelby |
John David Hunt FRS [ 1 ] (12 December 1936 – 8 December 2012) was a British metallurgist . His research career was mainly based at the University of Oxford , from 1966 to 2002.
His legacy includes the Institute of Materials, Minerals and Mining 's John Hunt Medal, awarded for 'outstanding contribution to the science and/or technology of casting and solidification of metals'. [ 2 ] He was elected Fellow of the Royal Society in 2001.
This article about a British scientist is a stub . You can help Wikipedia by expanding it .
This metallurgy -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/John_David_Hunt |
The John Desmond Bernal Prize is an award given annually by the Society for Social Studies of Science (4S) to scholars judged to have made a distinguished contribution to the interdisciplinary field of Science and Technology Studies (STS). [ 1 ] The award was launched in 1981, with the support of Eugene Garfield . [ 2 ]
The award is named after the scientist John Desmond Bernal .
Source: Society for Social Studies of Science Archived 2017-08-06 at the Wayback Machine | https://en.wikipedia.org/wiki/John_Desmond_Bernal_Prize |
The John Elder Professor of Naval Architecture and Ocean Engineering at the University of Glasgow , Scotland, was established in 1883 and endowed by Isabella Elder (1828-1905) in honor of her husband, John Elder . John Elder was a renowned marine engineer and shipbuilder of Randolph, Elder & Co. (1824-1869).
This article relating to education in Scotland is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/John_Elder_Professor_of_Naval_Architecture_and_Ocean_Engineering |
John Flinders Petrie (26 April 1907 – 1972) was an English mathematician. Petrie was the great grandson of the explorer and navigator, Matthew
Flinders. He met the geometer Harold Scott MacDonald Coxeter as a student, beginning a lifelong friendship. They collaborated in discovering infinite warped polyhedra and (finite) warped polyhedra in the fourth dimension, analogous to the previous ones. In addition to being the first to realize the importance of the warped polygon that now bears his name, he was also skilled as a draftsperson.
Petrie was born on 26 April 1907, in Hampstead , London. He was the only son of the renowned Egyptologists Sir William Matthew Flinders Petrie (and through him the great grandson of the explorer and navigator Matthew Flinders) and Hilda Petrie . [ 1 ] While studying at a boarding school, he met Coxeter in a sanatorium while recovering from a minor illness, beginning a friendship that would remain throughout their lives. [ 2 ] Looking at a geometry textbook with an appendix on Platonic polyhedra, they wondered why there were only five and tried to increase their number. Petrie commented: How about we put four squares around one corner? In practice, they would lie on a plane, forming a pattern of squares covering the plane. He called this arrangement a "tesserohedron", reaching the similar structure of triangles a "trigonohedron."
In 1926, Petrie told Coxeter that he had discovered two new regular polyhedra, infinite but free of "false vertices" (points distinct from the vertices, where three or more faces meet, like those that characterize regular star polyhedra): one consisting of squares, six at each vertex and another consisting of hexagons, four at each vertex, which form a dual or reciprocal pair. To the common objection that there is no room for more than four squares around a vertex, he revealed the trick: allow the faces to be arranged up and down, marking a zigzag. When Coxeter understood this, he mentioned a third possibility: hexagons, six around a vertex, its dual.
Coxeter suggested a modified Schläfli symbol , {l, m | n} for these figures, with the emblem {l, m} implying the vertex figure, m l-gons around a vertex and n-gonal holes. Then it occurred to them that, although the new polyhedra are infinite, they could find analogous finite polyhedra by delving into the fourth dimension. Petrie cited one consisting of n2 squares, four at each vertex. They called these figures "regular skew polyhedra". Later, Coxeter would delve deeper into the subject.
Because his father belonged to University College London , Petrie enrolled in this institution, where he successfully completed his studies. When the Second World War broke out, he enlisted as an officer and was captured as a prisoner by the Germans, organizing a choir during his captivity. After the war ended and he was released, he went to Darlington Hall, a school in southwest England. He worked many years as a schoolteacher. He was one of the tutors who attended to the children doing poorly in school.
Petrie continued to correspond with Coxeter and was the first to notice that, among the edges of a regular polyhedron , a skew polygon forming a zigzag can be distinguished, in which the first and second are the edges of one face, the second and third are the edges of another face and so on, successively. This zigzag is known as the " Petrie polygon " and has many applications. The Petrie polygon of a regular polyhedron can be defined as the skew polygon (whose vertices do not all lie in the same plane) such that every two consecutive sides (but not three) belong to one of the faces of the polyhedron.
Each finite regular polyhedron can be orthogonally projected onto a plane so that the Petrie polygon becomes a regular polygon, with the rest of the projection inside. These polygons and their projected graphs help visualize the symmetrical structure of regular polytopes of higher dimensions, which are difficult to conceive or imagine without this aid.
His skills as a draftsman are shown in an exquisite set of drawings of the stellated icosahedron, which provides much of the fascination of the much-discussed book he illustrates. On another occasion, to explain the symmetry of the icosahedron, Coxeter showed an orthogonal projection, representing 10 of the 15 great circles as ellipses. The difficult task of drawing was performed by Petrie around 1932. It now prominently features on the cover of a popular recreational mathematics book garnished with a touch of colour. It is reported that, in periods of intense concentration, he could answer questions about complex figures of the fourth dimension by "visualizing" them.
Petrie got married and had a daughter. In late 1972, his wife suffered a sudden heart attack and passed away. He missed her so much and was so distracted that one day he walked onto a highway near his home and was hit by a car while trying to cross it running. He died in Surrey, at 64, just two weeks after his wife. [ citation needed ] | https://en.wikipedia.org/wiki/John_Flinders_Petrie |
John William Gofman (21 September 1918 – 15 August 2007) was an American scientist and advocate. He was Professor Emeritus of Molecular and Cell Biology at the University of California at Berkeley .
Gofman pioneered the field of clinical lipidology , and in 2007 was honored by the Journal of Clinical Lipidology with the title of "Father of Clinical Lipidology". [ 2 ] With Frank T. Lindgren and other research associates, Gofman discovered and described three major classes of plasma lipoproteins , fat molecules that carry cholesterol in the blood. The team he led at the Donner Laboratory went on to demonstrate the role of lipoproteins in the causation of heart disease .
Gofman advocated for the adoption of the Linear No-Threshold (LNT) model as a means of estimating actual cancer risks from low-level radiation and as the foundation of the international guidelines for radiation protection.
Gofman's earliest research was in nuclear physics and chemistry, in close connection with the Manhattan Project . He codiscovered several radioisotopes , notably uranium-233 and its fissionability; he was the third person ever to work with plutonium and, having devised an early process for separating plutonium from fission products at J. Robert Oppenheimer 's request, [ 3 ] he was the first chemist ever to try and isolate milligram quantities of plutonium. [ 4 ]
In 1963 Gofman established the Biomedical Research Division for the Livermore National Laboratory , where he researched the connection between chromosomal abnormalities and cancer.
Later in life, Gofman became an anti-nuclear advocate. Beginning in 1971, he was Chairman of the Committee for Nuclear Responsibility . He was awarded the Right Livelihood Award for "his pioneering work in exposing the health effects of low-level radiation" on the Chernobyl disaster 's area population. [ 5 ]
In his 1996 book [ 6 ] Gofman claimed that exposure to medical x-rays was responsible for about 75 percent of breast cancers in the United States. This order of magnitude has been somehow confirmed by the increase in breast cancer incidence following mammography screening in the USA and in France. [ 7 ]
John Gofman graduated from Oberlin College with a bachelor's in chemistry in 1939, and received a doctorate in nuclear and physical chemistry from Berkeley in 1943, where he worked as a graduate student under Glenn T. Seaborg . In his PhD dissertation, Gofman described the discovery of radioisotopes protactinium -232, uranium-232 , protactinium-233, as well as uranium-233 and the characterization of its fissionability. [ 1 ]
Gofman shared three patents with collaborators on their discoveries :
Gofman later became the group co-leader of the Plutonium Project, an offshoot of the Manhattan Project . [ 9 ]
Dr. Gofman earned his medical degree from the University of California, San Francisco , in 1946. After that, he and his collaborators investigated the body's lipoproteins , which contain both proteins and fats , and their circulation within the bloodstream. The researchers described low-density and high-density lipoproteins and their roles in metabolic disorders and coronary disease. This work continued throughout the late 1940s and early 1950s. [ 9 ]
At the request of Ernest Lawrence , Gofman established the Medical Department at the Lawrence Livermore National Laboratory (LLNL) in early 1954 and acted as the medical director until 1957. [ 10 ]
Gofman retired as a teaching professor in 1973 and became a professor emeritus of molecular and cell biology.
Gofman used his low-level radiation health model to predict 333 excess cancer or leukemia deaths from the 1979 Three Mile Island accident . [ 11 ]
Three months after the Chernobyl disaster , Gofman predicted that Chernobyl would cause "475,000 fatal cancers plus about
an equal number of additional non-fatal cases, occurring over time both inside and outside the ex-Soviet Union". [ 12 ]
Gofman was born in Cleveland, Ohio to Jewish parents, David and Sarah Gofman, who immigrated to the US from the Russian Empire in about 1905. [ 13 ] His father had been "involved in some of the early revolutionary activities against the Czar ." [ 14 ] Gofman died of heart failure at age 88 on August 15, 2007, in his home in San Francisco. [ 15 ] | https://en.wikipedia.org/wiki/John_Gofman |
John William Hinchley (1871-1931) was a chemical engineer who was the first Secretary of the Institution of Chemical Engineers .
Hinchley was born 21 January 1871 in Grantham , [ 2 ] [ 1 ] and studied at Lincoln Grammar School . [ 2 ] [ 3 ] From 1887 to 1890 he served an engineering apprenticeship at Ruston, Proctor and Company [ 3 ] while attending science classes in the evening, being a prizewinner in chemistry, followed by a year as a science teacher. [ 4 ] A national scholarship and the support of a friend enabled him to go to Imperial College, London [ 2 ] where he graduated in 1895 with first class honours. [ 3 ] [ 5 ] He successfully sat the exam for a Whitworth Scholarship . [ 2 ]
After Imperial College, he went to Dublin to assist Professor John Joly with the development of colour photography . [ 3 ] [ 5 ] Returning to London he became assistant to a designer of acid plants and acetone production which stopped when his employer was killed in a road accident, so he became a chemical engineering consultant. [ 6 ] In 1903 he went to Siam to be the technical head of the new Royal Mint of Bangkok , [ 2 ] [ 3 ] [ 7 ] successfully developing a process melting 2.5 tons of silver a day and coinage to British Royal Mint standards. [ 8 ] Back in London he was again a consultant, designing and erecting a variety of chemical plants. [ 9 ]
In 1909 he was invited to give a series of 25 lectures on chemical engineering at Battersea Technical College , [ 10 ] the first regular curriculum in the subject in the UK. [ 11 ] [ 12 ] These were popular, and in 1911 he was appointed lecturer in chemical engineering for two days a week at Imperial College, [ 13 ] [ 10 ] in 1917 becoming assistant professor, all the while continuing with his professional work, but passing on the course at Battersea. [ 14 ] [ 15 ] The same year he was promoted to the class of Fellows of the Institute of Chemistry. [ 16 ] In 1926 he was made full Professor. [ 2 ] [ 17 ] The same year the article on Chemical Engineering in Encyclopedia Britannica was his work. [ 18 ]
George E. Davis proposed the formation of a Society of Chemical Engineers, but instead the Society of Chemical Industry (SCI) was formed. [ 19 ] [ 20 ] In 1918 Hinchley, who was a Council Member of the SCI, petitioned it to form a Chemical Engineers Group, which was done, with him as chairman and 510 members [ 21 ] In 1920 this group voted to form a separate Institution of Chemical Engineers, which was achieved in 1922 with Hinchley as the Secretary, a role he held until his death. [ 22 ] According to the editor of Chemical Age just after his death, "The establishment, a few years later, of the Institution of Chemical Engineers was due to him perhaps more than any single person." [ 23 ] The journal Nature described him as instrumental in its formation. [ 3 ]
It was while at Imperial College that he was introduced to a student at the Royal College of Art , Edith Mary Mason . [ 24 ] She was later a member of the Royal Society of Miniature Painters, Sculptors and Gravers . [ 25 ] They were married on 4 August 1903. [ 7 ] She designed the Seal for the Institution of Chemical Engineers, which was executed by medallist Cecil Thomas , a fellow member of the same Royal Society. [ 26 ] [ 27 ]
While in Siam, he became a freemason and was involved in setting up the Imperial College Masonic lodge . [ 3 ]
He died 13 August 1931 after a long illness. [ 2 ] [ 28 ] [ 29 ] He was cremated at Golders Green Crematorium and the ashes scattered in the Garden of Rest, [ 30 ] where there is now a memorial. [ 31 ]
The Institution of Chemical Engineers instituted an annual Hinchley Memorial Lecture in 1932 [ 32 ] and a Hinchley Medal in 1943 for the most meritorious student of chemical engineering at Imperial College. The Medal continues, but is now directly awarded by the college. [ 33 ] [ 34 ] | https://en.wikipedia.org/wiki/John_Hinchley |
John Horton Conway FRS (26 December 1937 – 11 April 2020) was an English mathematician. He was active in the theory of finite groups , knot theory , number theory , combinatorial game theory and coding theory . He also made contributions to many branches of recreational mathematics , most notably the invention of the cellular automaton called the Game of Life .
Born and raised in Liverpool , Conway spent the first half of his career at the University of Cambridge before moving to the United States, where he held the John von Neumann Professorship at Princeton University for the rest of his career. [ 2 ] On 11 April 2020, at age 82, he died of complications from COVID-19 . [ 3 ]
Conway was born on 26 December 1937 in Liverpool , the son of Cyril Horton Conway and Agnes Boyce. [ 2 ] [ 4 ] He became interested in mathematics at a very early age. By the time he was 11, his ambition was to become a mathematician. [ 5 ] [ 6 ] After leaving sixth form , he studied mathematics at Gonville and Caius College, Cambridge . [ 4 ] A "terribly introverted adolescent" in school, he took his admission to Cambridge as an opportunity to transform himself into an extrovert, a change which would later earn him the nickname of "the world's most charismatic mathematician". [ 7 ] [ 8 ]
Conway was awarded a BA in 1959 and, supervised by Harold Davenport , began to undertake research in number theory. Having solved the open problem posed by Davenport on writing numbers as the sums of fifth powers , Conway became interested in infinite ordinals. [ 6 ] It appears that his interest in games began during his years studying the Cambridge Mathematical Tripos , where he became an avid backgammon player, spending hours playing the game in the common room. [ 2 ]
In 1964, Conway was awarded his doctorate and was appointed as College Fellow and Lecturer in Mathematics at Sidney Sussex College, Cambridge . [ 9 ]
After leaving Cambridge in 1986, he took up the appointment to the John von Neumann Chair of Mathematics at Princeton University. [ 9 ] There, he won the Princeton University Pi Day pie-eating contest. [ 10 ]
Conway's career was intertwined with that of Martin Gardner . When Gardner featured Conway's Game of Life in his Mathematical Games column in October 1970, it became the most widely read of all his columns and made Conway an instant celebrity. [ 11 ] [ 12 ] Gardner and Conway had first corresponded in the late 1950s, and over the years Gardner had frequently written about recreational aspects of Conway's work. [ 13 ] For instance, he discussed Conway's game of Sprouts (July 1967), Hackenbush (January 1972), and his angel and devil problem (February 1974). In the September 1976 column, he reviewed Conway's book On Numbers and Games and even managed to explain Conway's surreal numbers . [ 14 ]
Conway was a prominent member of Martin Gardner's Mathematical Grapevine . He regularly visited Gardner and often wrote him long letters summarizing his recreational research. In a 1976 visit, Gardner kept him for a week, pumping him for information on the Penrose tilings which had just been announced. Conway had discovered many (if not most) of the major properties of the tilings. [ 15 ] Gardner used these results when he introduced the world to Penrose tiles in his January 1977 column. [ 16 ] The cover of that issue of Scientific American features the Penrose tiles and is based on a sketch by Conway. [ 12 ]
Conway invented the Game of Life, one of the early examples of a cellular automaton . His initial experiments in that field were done with pen and paper, long before personal computers existed. Since Conway's game was popularized by Martin Gardner in Scientific American in 1970, [ 17 ] it has spawned hundreds of computer programs, web sites, and articles. [ 18 ] It is a staple of recreational mathematics. The LifeWiki is devoted to curating and cataloging the various aspects of the game. [ 19 ] From the earliest days, it has been a favorite in computer labs, both for its theoretical interest and as a practical exercise in programming and data display. Conway came to dislike how discussions of him heavily focused on his Game of Life, feeling that it overshadowed deeper and more important things he had done, although he remained proud of his work on it. [ 20 ] The game helped to launch a new branch of mathematics, the field of cellular automata . [ 21 ] The Game of Life is known to be Turing complete . [ 22 ] [ 23 ]
Conway contributed to combinatorial game theory (CGT), a theory of partisan games . He developed the theory with Elwyn Berlekamp and Richard Guy , and also co-authored the book Winning Ways for your Mathematical Plays with them. He also wrote On Numbers and Games ( ONAG ) which lays out the mathematical foundations of CGT.
He was also one of the inventors of the game sprouts , as well as philosopher's football . He developed detailed analyses of many other games and puzzles, such as the Soma cube , peg solitaire , and Conway's soldiers . He came up with the angel problem , which was solved in 2006.
He invented a new system of numbers, the surreal numbers , which are closely related to certain games and have been the subject of a mathematical novelette by Donald Knuth . [ 24 ] He also invented a nomenclature for exceedingly large numbers , the Conway chained arrow notation . Much of this is discussed in the 0th part of ONAG .
In the mid-1960s with Michael Guy , Conway established that there are sixty-four convex uniform polychora excluding two infinite sets of prismatic forms. They discovered the grand antiprism in the process, the only non-Wythoffian uniform polychoron . [ 25 ] Conway also suggested a system of notation dedicated to describing polyhedra called Conway polyhedron notation .
In the theory of tessellations, he devised the Conway criterion which is a fast way to identify many prototiles that tile the plane. [ 26 ]
He investigated lattices in higher dimensions and was the first to determine the symmetry group of the Leech lattice .
In knot theory, Conway formulated a new variation of the Alexander polynomial and produced a new invariant now called the Conway polynomial. [ 27 ] After lying dormant for more than a decade, this concept became central to work in the 1980s on the novel knot polynomials . [ 28 ] Conway further developed tangle theory and invented a system of notation for tabulating knots, now known as Conway notation , while correcting a number of errors in the 19th-century knot tables and extending them to include all but four of the non-alternating primes with 11 crossings. [ 29 ] The Conway knot is named after him.
Conway's conjecture that, in any thrackle , the number of edges is at most equal to the number of vertices, is still open.
He was the primary author of the ATLAS of Finite Groups giving properties of many finite simple groups . Working with his colleagues Robert Curtis and Simon P. Norton he constructed the first concrete representations of some of the sporadic groups . More specifically, he discovered three sporadic groups based on the symmetry of the Leech lattice , which have been designated the Conway groups . [ 30 ] This work made him a key player in the successful classification of the finite simple groups .
Based on a 1978 observation by mathematician John McKay , Conway and Norton formulated the complex of conjectures known as monstrous moonshine . This subject, named by Conway, relates the monster group with elliptic modular functions , thus bridging two previously distinct areas of mathematics— finite groups and complex function theory . Monstrous moonshine theory has now been revealed to also have deep connections to string theory . [ 31 ]
Conway introduced the Mathieu groupoid , an extension of the Mathieu group M 12 to 13 points.
As a graduate student, he proved one case of a conjecture by Edward Waring , that every integer could be written as the sum of 37 numbers each raised to the fifth power, though Chen Jingrun solved the problem independently before Conway's work could be published. [ 32 ] In 1972, Conway proved that a natural generalization of the Collatz problem is algorithmically undecidable . Related to that, he developed the esoteric programming language FRACTRAN . While lecturing on the Collatz conjecture, Terence Tao (who was taught by him in graduate school) mentioned Conway's result and said that he was "always very good at making extremely weird connections in mathematics". [ 33 ]
Conway wrote a textbook on Stephen Kleene 's theory of state machines, and published original work on algebraic structures , focusing particularly on quaternions and octonions . [ 34 ] Together with Neil Sloane , he invented the icosians . [ 35 ]
He invented a base 13 function as a counterexample to the converse of the intermediate value theorem : the function takes on every real value in each interval on the real line, so it has a Darboux property but is not continuous .
For calculating the day of the week, he invented the Doomsday algorithm . The algorithm is simple enough for anyone with basic arithmetic ability to do the calculations mentally. Conway could usually give the correct answer in under two seconds. To improve his speed, he practised his calendrical calculations on his computer, which was programmed to quiz him with random dates every time he logged on. One of his early books was on finite-state machines .
In 2004, Conway and Simon B. Kochen , another Princeton mathematician, proved the free will theorem , a version of the " no hidden variables " principle of quantum mechanics . It states that given certain conditions, if an experimenter can freely decide what quantities to measure in a particular experiment, then elementary particles must be free to choose their spins to make the measurements consistent with physical law. Conway said that "if experimenters have free will , then so do elementary particles." [ 36 ]
Conway was married three times. With his first two wives he had two sons and four daughters. He married Diana in 2001 and had another son with her. [ 37 ] He had three grandchildren and two great-grandchildren. [ 2 ]
On 8 April 2020, Conway developed symptoms of COVID-19 . [ 38 ] On 11 April, he died in New Brunswick , New Jersey , at the age of 82. [ 38 ] [ 39 ] [ 40 ] [ 41 ] [ 42 ]
Conway received the Berwick Prize (1971), [ 43 ] was elected a Fellow of the Royal Society (1981), [ 44 ] [ 45 ] became a fellow of the American Academy of Arts and Sciences in 1992, was the first recipient of the Pólya Prize (LMS) (1987), [ 43 ] won the Nemmers Prize in Mathematics (1998) and received the Leroy P. Steele Prize for Mathematical Exposition (2000) of the American Mathematical Society . In 2001 he was awarded an honorary degree from the University of Liverpool , [ 46 ] and in 2014 one from Alexandru Ioan Cuza University . [ 47 ]
His Fellow of the Royal Society nomination in 1981 reads:
A versatile mathematician who combines a deep combinatorial insight with algebraic virtuosity, particularly in the construction and manipulation of "off-beat" algebraic structures which illuminate a wide variety of problems in completely unexpected ways. He has made distinguished contributions to the theory of finite groups, to the theory of knots, to mathematical logic (both set theory and automata theory) and to the theory of games (as also to its practice). [ 44 ]
In 2017 Conway was given honorary membership of the British Mathematical Association . [ 48 ]
Conferences called Gathering 4 Gardner are held every two years to celebrate the legacy of Martin Gardner, and Conway himself was often a featured speaker at these events, discussing various aspects of recreational mathematics. [ 49 ] [ 50 ] | https://en.wikipedia.org/wiki/John_Horton_Conway |
The John Innes Centre ( JIC ), located in Norwich , Norfolk, England, is an independent centre for research and training in plant and microbial science founded in 1910. It is a registered charity (No 223852) grant-aided by the Biotechnology and Biological Sciences Research Council (BBSRC) , the European Research Council (ERC) and the Bill and Melinda Gates Foundation and is a member of the Norwich Research Park . [ 2 ] [ 3 ] In 2017, the John Innes Centre was awarded a gold Athena SWAN Charter award. [ 4 ]
The John Innes Horticultural Institution [ 5 ] was founded in 1910 at Merton Park , Surrey (now London Borough of Merton ), with funds bequeathed by John Innes , a merchant and philanthropist. The Institution occupied Innes's former estate at Merton Park, Surrey until 1945 when it moved to Bayfordbury , Hertfordshire. It moved to its present site in 1967. [ 6 ]
In 1910, William Bateson became the first director of the John Innes Horticultural Institution and moved with his family to Merton Park. John Innes compost was developed by the institution in the 1930s, who donated the recipe to the " Dig for Victory " war effort. The John Innes Centre has never sold John Innes compost.
During the 1980s, the administration of the John Innes Institute was combined with that of the Plant Breeding Institute [ 7 ] [ 8 ] [ 9 ] [ 10 ] (formerly at Trumpington, Cambridgeshire ) and the Nitrogen Fixation Laboratory. In 1994, following the relocation of the operations of other two organisations to the Norwich site, the three were merged as the John Innes Centre. [ 6 ]
As of 2011 the institute was divided into six departments: Biological Chemistry, Cell & Developmental Biology, Computational & Systems Biology, Crop Genetics, Metabolic Biology and Molecular Microbiology. [ 11 ]
The John Innes Centre has a tradition of training PhD students and post-docs. PhD degrees obtained via the John Innes Centre are awarded by the University of East Anglia . The John Innes Centre has a contingent of postdoctoral researchers , many of whom are recruited onto the institute's Post-doctoral Training Fellowship programme. The John Innes Centre also sponsors seminars and lectures, including the Bateson Lecture , Biffen Lecture , Chatt Lecture , Darlington Lecture and Haldane Lecture . [ 12 ] In February 2025, the John Innes Centre announced the appointment [ 13 ] of Professor Cristóbal Uauy as its next director, effective September 2025.
The research at the John Innes Centre is divided into four Institute Strategic Programs (ISPs) funded by the Biotechnology and Biological Sciences Research Council (BBSRC) . [ 14 ] These ISPs, which combine the research of multiple groups to address a greater aim, were, from 2017 to 2023 as follows:
The John Innes Centre co-located with The Sainsbury Laboratory (Norwich), [ 15 ] an institute focused studying plant disease. The Sainsbury Laboratory is closely affiliated with the University of East Anglia . [ 16 ] Along with the Institute of Food Research [ 17 ] and University of East Anglia (UEA), [ 16 ] JIC hosted the BA Festival of Science (now the British Science Festival ) in September 2006. [ 18 ] The John Innes Centre, University of East Anglia (UEA) [ 16 ] The Sainsbury Laboratory , [ 15 ] The Earlham Institute and Quadram Institute Bioscience have since 2016, run Women of the Future [ 19 ] an event aimed at promoting career in science to young women.
The John Innes Centre has been directed by:
Notable staff and alumni include:
The John Innes Foundation (JIF) is an independent charitable foundation (registered Charity No. 1111527) and was formed in 1910 by John Innes . JIF set up the John Innes Horticultural Institution (JIHI) in London. Currently, the JIF owns the land and buildings at Newfound Farm in Bawburgh, Norfolk which are used by researchers from the John Innes Centre. The JIF trustees also play an active part in the management of John Innes Centre research and have the right to appoint three members of the Governing Council. The foundation sponsors several graduate studentships each year, support for educational programmes and the infrastructure of the site. They also fund student awards for scientific excellence and science communication. [ 20 ] It also owns a very significant collection of archive material held in the Historical Collections library at the John Innes Centre. [ 21 ]
The John Innes Centre is home to a collection of rare botanical books, lab books, manuscripts and letters documenting the history of genetics and research carried out by its scientists. This includes a letter from William Bateson documenting the first use of the word " genetics ". [ 22 ] The History of Genetics library also contains the archives of the Genetical Society. [ 23 ] [ 24 ]
An important part of the John Innes Centre is the John Innes Centre Germplasm Resources Unit (GRU). [ 25 ] This seedbank houses a number of germplasm collections, including the Watkins Landrace Wheat Collection , the John Innes Centre Pisum Collection , BBSRC Small Grain Cereal Collection, Crop wild relative collection and several specialist genetic stocks collections. This material is extensively used by UK and non-UK researchers and breeders, and is an available upon request to research, academic and commercial efforts, subject to availability. The complete list of the material can be found in the GRU database. [ 26 ] | https://en.wikipedia.org/wiki/John_Innes_Centre |
The John J. Abel Award is an annual award presented by the American Society for Pharmacology and Experimental Therapeutics (ASPET). The award is given for outstanding research in the field of pharmacology and/or experimental therapeutics; which comes with a $5000 prize, An engraved plaque, and all travel expenses paid to attend the ASPET Annual Meeting at Experimental Biology. [ 1 ] The Award is named after American biochemist and pharmacologist , John Jacob Abel . | https://en.wikipedia.org/wiki/John_J._Abel_Award |
John Joseph Jolly Kyle FRSA (2 February 1838 – 23 February 1922) was a pioneering Argentine chemist . Born and educated in Scotland , he emigrated to Argentina in 1862, and on the outbreak of the Paraguayan War served as a pharmacist in the Argentine Army medical corps . He became an Argentine citizen in 1873. At the time Kyle was active specialisation was not an option in Latin American chemistry and it was necessary for a chemist to be a sort of polymath or jack-of-all-trades. [ 1 ] Kyle was appointed professor of chemistry at the Colegio Nacional de Buenos Aires in 1871, and chief chemist to the Casa de Moneda de la República Argentina (the Argentine Mint) in 1881. He was appointed professor of organic chemistry at the University of Buenos Aires (1889); Chemist to the Inspectorate-General of Sanitary Works (1890); professor of industrial chemistry at the Colegio Nacional (1892); and professor of inorganic chemistry at Buenos Aires University (1896). He was director of the first chemistry doctoral thesis in Argentina (1901). [ 2 ]
The Dr. Juan J. J. Kyle Award [ es ] , awarded quinquennially by the Argentine Chemical Association for the best contribution to any branch of chemistry, and its most prestigious prize, is named in his honour. [ 3 ]
Kyle was born in Stirling , Scotland on 2 February 1838. He completed an apprenticeship with an Edinburgh pharmacy in 1854 and became assistant to Dr Stevenson Macadam , lecturer in chemistry to Surgeons' Hall , Edinburgh. He made his first scientific discovery at the age of 18. [ 4 ] Moving to the field of industrial chemistry, he was head of the chemical laboratory of Glasgow University and then manager of an animal charcoal manufacturer in Greenock . He was a fellow of the Royal Society of Arts . [ 5 ]
He emigrated to Argentina in July 1862. When President-Marshall Solano Lopez of Paraguay invaded Corrientes Province in 1865 there broke out the War of the Triple Alliance and Kyle joined the medical corps of the Argentine Army as a pharmacist with the rank of lieutenant. He participated in the siege of Uruguaiana (where the defenders were reduced to living on lump sugar), the three-day battle of the Boquerón and in the Battle of Tuyutí , the bloodiest international battle in the history of South America. He served on board the hospital ship Pavón and returned to Buenos Aires in December 1866 in charge of a convoy of wounded soldiers. His wartime experiences led him to take a foundational interest in the Argentine Red Cross Society, of which he was made an honorary member in 1896.
By the time of his retirement in 1906 he had published some 65 chemical papers, most of them in the Spanish language, on such diverse topics as the chemical compositions of Argentine rivers, the medicinal plants of Córdoba Province, Argentina , the incrustation of locomotive boilers, the presence of organic matter in drinking water, the caffeine content of yerba mate , the adulteration of saffron , the wines of the Argentine Republic, compositions of meteorites fallen in Buenos Aires Province , Patagonian guano , the petroleum of Jujuy Province , a new alkaloid he isolated from Ruprechtia salicifolia , Cape Virgins gold, Tierra del Fuego platinum , well water , the cement of a failed dam, the destruction of masonry by cloacal gases, and a silver-yielding manganese ore from Mendoza Province . [ 6 ] [ 7 ]
According to Rapela and Depetris, Kyle was the first Argentine geochemist . Of his papers,
The most relevant are those related to the characteristics and composition of ground waters in the province of Buenos Aires. Along with studies on the best location for groundwater wells, he advised on the collection of freshwater from rivers to supply the city of Buenos Aires [ 8 ]
On a vanadiferous lignite found in the Argentine Republic with analysis of the ash [ 9 ] was read before the British Association Edinburgh meeting in 1892. His last work, published in Ambrosetti, El bronce en la region calchaquí [ 10 ] established that the Calchaquí Amerindians were a Bronze Age people. He died in Buenos Aires on 23 February 1922. | https://en.wikipedia.org/wiki/John_Joseph_Jolly_Kyle |
John Kay (17 June 1704 – c. 1779) was an English inventor whose most important creation was the flying shuttle , which was a key contribution to the Industrial Revolution . He is often confused with his namesake , [ 10 ] [ 11 ] who built the first "spinning frame". [ 12 ]
John Kay was born on 17 June 1704 in the Lancashire hamlet of Walmersley , [ 4 ] just north of Bury . His yeoman farmer father, Robert, owned the "Park" estate in Walmersley, and John was born there. [ 13 ] Robert died before John was born, leaving Park House to his eldest son. As Robert's fifth son (out of ten children), John was bequeathed £40 (at age 21) and an education until the age of 14. [ 14 ] His mother was responsible for educating him until she remarried.
He apprenticed with a hand-loom reed maker, but is said to have returned home within a month claiming to have mastered the business. [ 15 ] He designed a metal substitute for the natural reed that proved popular enough for him to sell throughout England. [ 11 ] After travelling the country, making and fitting wire reeds, he returned to Bury and, on 29 June 1725, both he and his brother, William, married Bury women. John's wife was Anne Holte. [ 16 ] His daughter Lettice was born in 1726, and his son Robert in 1728. [ 17 ]
In Bury he continued to design improvements to textile machinery; in 1730 he patented a cording and twisting machine for worsted . [ 18 ]
In 1733, [ 19 ] he received a patent for his most revolutionary device: a "wheeled shuttle " for the hand loom . [ 20 ] [ 21 ] It greatly accelerated weaving , [ 22 ] by allowing the shuttle carrying the weft to be passed through the warp threads faster and over a greater width of cloth. [ 23 ] It was designed for the broad loom, for which it saved labour over the traditional process , needing only one operator per loom (before Kay's improvements a second worker was needed to catch the shuttle). [ 24 ]
Kay always called this invention a "wheeled shuttle", but others used the name "fly-shuttle" (and later, "flying shuttle") because of its continuous speed, especially when a young worker was using it in a narrow loom. The shuttle was described as travelling at "a speed which cannot be imagined, so great that the shuttle can only be seen like a tiny cloud which disappears the same instant." [ 25 ]
In July 1733, Kay formed a partnership in Colchester , Essex to begin fly-shuttle manufacturing. [ 26 ] No industrial unrest was anticipated, this being the first device of the modern era to significantly enhance productivity. [ 27 ] But by September 1733 the Colchester weavers, were so concerned for their livelihoods that they petitioned the King to stop Kay's inventions. [ 26 ]
The flying shuttle was to create a particular imbalance by doubling weaving productivity without changing the rate at which thread could be spun, [ 28 ] disrupting spinners and weavers alike.
Kay tried to promote the fly-shuttle in Bury, but could not convince the woollen manufacturers that it was sufficiently robust; he spent the next two years improving the technology, until it had several advantages over the device specified in the 1733 patent. This was to be one of his difficulties in the coming patent disputes. [ 29 ]
In 1738 Kay went to Leeds , where his problem had become royalty collection [ 30 ] (the annual licence fee was 15 Shillings per shuttle). [ 5 ] He continued to invent, patenting some machines in the same year, though these were not taken up industrially. [ 31 ]
Kay (and, initially, his partners) launched numerous patent infringement lawsuits, but if any of these cases were successful, [ 32 ] compensation was below the cost of prosecution. Rather than capitulate, the manufacturers formed "the Shuttle Club", a syndicate which paid the costs of any member brought to court; their strategy of patent piracy and mutual indemnification nearly bankrupted Kay. [ 33 ]
In 1745, he and Joseph Stell patented a machine for cloth ribbon weaving , which they anticipated might be worked by water wheel , [ 19 ] but they were unable to advance their plans because of Kay's legal costs. [ 31 ] Impoverished and harassed, Kay was compelled to leave Leeds, and he returned to Bury. [ 34 ] Also in 1745, John's twelfth, and final, child, William, was born. [ 9 ]
Kay remained inventive; in 1746 he was working on an efficient method of salt production, [ 35 ] and designing improvements to spinning technology: but that made him unpopular among Bury spinners. [ 34 ] Also, fly-shuttle use was becoming widespread in weaving, [ 36 ] increasing cotton yarn demand and its price ; and Kay was blamed. [ 37 ]
He had suffered violent treatment in England, but he did not leave the country on that account, but because of his inability to enforce (or profit from) his patent rights. [ 38 ] Trudaine's Bureau de Commerce was known to support textile innovations (and would later actively recruit immigrant inventors). [ 39 ] Probably encouraged by the prospect of state support, [ 40 ] in 1747, Kay left England for France (where he had never been before, and did not speak the language).
Kay went to Paris, and throughout 1747 negotiated with the French Government (in English) to sell them his technology. [ 41 ]
Denied the huge lump sum he wanted, Kay finally agreed to 3,000 livres plus a pension of 2,500 livre , [ 5 ] (annually from 1749) in exchange for his patent, and instruction in its use (to the manufactures of Normandy ). He retained the sole rights to shuttle production in France, [ 42 ] and brought three of his sons to Paris to make them. Although wary of entering the manufacturing provinces (because of his experiences with rioting weavers in England) he was prevailed upon to do so.
At one time, the French authorities may have discouraged his communication with England, [ 43 ] but Kay wrote about the unanticipated use of his technology in England to the French government: "My new shuttles are also used in England to make all sorts of narrow woollen goods, although their use could have been more perfect had the weavers consulted me ". [ 44 ]
The beginning of mechanisation in French textile production is traditionally dated to 1753, with the widespread adoption of the flying shuttle there. [ 45 ] Most of these new shuttles were copies, not made by the Kays. John Kay unsuccessfully tried to enforce his manufacturing monopoly, and began to quarrel with the French authorities, briefly returning to England, in 1756 [ 46 ] (it is said [ by whom? ] that he was in his Bury home in 1753 when it was vandalised by a mob, and that he narrowly escaped with his life, [ 31 ] [ 47 ] but this is probably a 19th-century tale based on earlier Colchester riots; Kay was probably in France throughout the early 1750s). [ 48 ]
He found his prospects in England unimproved; by 1758 he was back in France, which became his adopted country, [ 5 ] though he was to visit England at least twice more. In the winter of 1765/66 he appealed to the Royal Society of Arts to reward him for his inventions, and exhibited his card-making machine for them. The Society could find no-one who understood the shuttle, [ 34 ] and there was a breakdown in correspondence, so that no award was ever made. He was in England again in 1773, but returned to France in 1774 having lost his pension (at aged 70).
His offer to teach pupils if the pension were restored was not taken up, and he spent his remaining years developing and building machines for cotton manufacturers in Sens and Troyes . Though he was busy with engineering and letter-writing until 1779, he received only 1,700 livres from the French state over these five years, reaching a state of penury in March 1778 before receiving his final advance (to develop yet more machinery). [ 49 ]
His last known letter (8 June 1779) listed his latest achievements for the Intendant de Commerce , and proposed further inventions. But since these were never made, and no more is heard of the 75-year-old Kay, it is believed that he must have died later in 1779. [ 7 ]
In Bury, Kay has become a local hero: there are still several pubs named after him, as are the Kay Gardens. [ 50 ] Bury town centre has William Venn Gough 's 1908 Memorial to John Kay (sculpture by John Cassidy ). [ 51 ] Planning began after a 1903 Bury public meeting launched a public subscription. 19th century efforts to acknowledge Kay achieved little, but by 1903 it was felt that Bury "owed John Kay's memory an atonement ", and that all Bury should contribute in restitution to "that wonderfully ingenious and martyred man". [ 52 ]
John Kay's son, Robert, stayed in Britain , [ 53 ] and in 1760 developed the "drop-box", [ 19 ] [ 54 ] which enabled looms to use multiple flying shuttles simultaneously, allowing multicolour wefts. [ 23 ]
His son John ("French Kay") had long resided with his father in France. In 1782 he provided an account of his father's troubles to Richard Arkwright , who sought to highlight problems with patent defence in a parliamentary petition. [ 55 ]
Ford Madox Brown portrayed Kay and his invention in a mural painting in Manchester Town Hall .
In the 1840s, one of Kay's great-grandsons, Thomas Sutcliffe , campaigned to promote a Colchester heritage for Kay's family. In 1846 he unsuccessfully sought a parliamentary grant for Kay's descendants in compensation for his ancestor's treatment in England. [ 31 ] He was inaccurate in the details of his grandfather's genealogy and story, and his "Fanciful and Erroneous Statements" were discredited by John Lord's detailed examination of primary sources . [ 56 ] [ 57 ] [ 58 ] | https://en.wikipedia.org/wiki/John_Kay_(flying_shuttle) |
John L. Pollock (1940–2009) was an American philosopher known for influential work in epistemology , philosophical logic , cognitive science , and artificial intelligence .
Born John Leslie Pollock in Atchison, Kansas, on January 28, 1940, Pollock earned a triple-major physics , mathematics , and philosophy degree at the University of Minnesota in 1961. In 1965, his doctoral dissertation Analyticity and Implication at the University of California, Berkeley was advised by Ernest Adams (making Pollock an intellectual descendant of Gottfried Leibniz and Immanuel Kant , through Ernest Nagel and Patrick Suppes ). [ 1 ] This dissertation contained an appendix on defeasible reasoning that would eventually blossom into his main contribution to philosophy.
Pollock held faculty positions at SUNY Buffalo , University of Rochester , University of Michigan , and University of Arizona , where he spent most of his career. At Arizona, he helped found the Cognitive Science Program. He was an avid mountain biker and founded a riding club in Southern Arizona.
Knowledge and Justification is the book that established Pollock in epistemology. It appeared at a time when American philosophy, and especially American epistemology, was obsessed with the analysis of what it means to know something. For instance, the Gettier problem , one of the most frequently discussed problems of the day, asks why it is that holding a "justified true belief" that x is not equivalent to knowing that x. Pollock's book steps back from trying to identify the "analytic criteria" which might constitute the necessary and sufficient conditions for knowledge. His epistemic norms are governed by defeasible reasoning; they are ceteris paribus conditions that can admit exceptions. Several other epistemologists (notably at Brown University , such as Ernest Sosa , and especially Roderick Chisholm ), as well as his Arizona colleague Keith Lehrer , had written about defeasibility and epistemology. But Pollock's book, which combined a broad scope and a crucial innovation, brought the ideas into the philosophical mainstream.
Pollock became known as "Mr. Defeasible Reasoning" among philosophers in the two decades before his death. In artificial intelligence , where non-monotonic reasoning had caused intellectual upheaval, scholars sympathetic to Pollock's work held him in great esteem for his early commitment and clarity. Pollock's most direct pronouncement is the paper "Defeasible reasoning" in Cognitive Science , 1987, though his non-syntactic ideas were almost fully mature in Knowledge and Justification . Pollock traced the history of his own thinking (e.g., in a footnote in Pollock and Cruz, Contemporary Theories of Knowledge, 1999, p. 36, note 37, and elsewhere) to his first paper on epistemology, "Criteria and our knowledge of the material world," Philosophical Review 76 , 1967. He thought that Roderick Chisholm had influenced his thinking on the subject, but he also said he was attempting to interpret Ludwig Wittgenstein directly, and sometimes credited Stephen Toulmin on the subject of argument. Although his work had considerable impact in the area of Artificial intelligence and law , Pollock was not himself interested much in jurisprudence or theories of legal reasoning, and he never acknowledged the inheritance of defeasible reasoning through H.L.A. Hart . Pollock also held informal logicians and scholars of rhetoric at a distance, though defeasible reasoning has natural affinities in argument .
Pollock's "undercutting defeat" and "rebutting defeat" are now fixtures in the defeasible reasoning literature. He later added "self-defeat" and other kinds of defeat mechanisms, but the original distinction remains the most popular.
Although aided by a strong tail wind from AI and a few contemporary like minded philosophers (e.g., Donald Nute, Nicholas Asher, Bob Causey), it is certain that defeasible reasoning went from the obscure to the mainstream in philosophy because of John Pollock, in the short time between the publication of Knowledge and Justification and the second edition of Contemporary Theories of Knowledge .
Pollock devoted considerable time later in his career to a software project called OSCAR , an artificial intelligence software prototype he called an "artilect". OSCAR was largely an implementation of Pollock's ideas on defeasible reasoning, but it also embodied his less well known and often unpublished ideas about intentions, interests, strategies for problem solving, and other cognitive architectural design. OSCAR was a LISP -based program that had an "interest-based" reasoner. Pollock claimed that the efficiency of his theorem-prover was based on its unwillingness to draw "uninteresting" conclusions. Although OSCAR did not benefit from the contributions of a large number of professional programmers, it must be compared to CyC , Soar (cognitive architecture) , and Novamente for its inventor's ambition.
Pollock described Oscar's main features as the ability to reason defeasibly about perception,
change and persistence, causation, probabilities, plan construction and evaluation, and decision. [ 2 ] He described the evolution of Oscar in the Fable of Oscar in his book.
OSCAR grew out of the Prologemena on How to Build a Person , which colleagues must have assumed was a facetious use of personhood at the time. However, Pollock's own attitude toward OSCAR was more machinating: he looked forward to future cognitive taxonomies that would classify OSCAR generously as a legitimate anthropomorphic form.
Nomic Probability and the Foundations of Induction, Oxford, 1990 was Pollock's deep investigation of the relationship between defeasible reasoning and the estimation of probability from frequencies (direct inference of probability). It is a maturation of ideas originally found in a 1983 Theory and Decision paper. This work must be compared to Henry E. Kyburg 's theories of probability, although Pollock believed that he was theorizing about a broader variety of statistical inferences . | https://en.wikipedia.org/wiki/John_L._Pollock |
John Lane Bell FRSC (born March 25, 1945) is an Anglo-Canadian philosopher, mathematician and logician. He is Professor Emeritus of Philosophy at the University of Western Ontario in Canada. His research includes such topics as set theory , model theory , lattice theory , modal logic , quantum logic , constructive mathematics , type theory , topos theory , infinitesimal analysis , spacetime theory, and the philosophy of mathematics . He is the author of more than 70 articles and of 13 books. In 2009, he was elected a Fellow of the Royal Society of Canada .
John Bell was awarded a scholarship to Oxford University at the age of 15, and graduated with a D.Phil. in Mathematics: his dissertation supervisor was John Crossley . During 1968–89 he was Lecturer in Mathematics and Reader in Mathematical Logic at the London School of Economics . [ 1 ]
Bell's students include Graham Priest (Ph.D. Mathematics LSE, 1972), Michael Hallett (Ph.D. Philosophy LSE, 1979), David DeVidi (Ph.D. Philosophy UWO, 1994), Elaine Landry (Ph.D. Philosophy UWO, 1997) and Richard A. Feist (Ph.D. Philosophy UWO, 1999). | https://en.wikipedia.org/wiki/John_Lane_Bell |
Edward John Lemmon (1 June 1930 – 29 July 1966) was a British logician and philosopher born in Sheffield , England . He is most well known for his work on modal logic , particularly his joint text with Dana Scott published posthumously (Lemmon and Scott, 1977).
Lemmon attended King Edward VII School [ 1 ] in Sheffield until 1947, before reading Literae humaniores at Magdalen College, Oxford , as an undergraduate, and was appointed Fellow of Trinity College, Oxford , in 1957. In 1963, following a visiting professorship in Texas , Lemmon emigrated to the United States to lecture at the Claremont Graduate School (now Claremont Graduate University ). Lemmon died from heart failure while climbing.
John Lemmon became interested in modal logic when Arthur Prior visited Oxford University in 1956 to give the John Locke lectures , later published as his Time and Modality (Prior 1957). Prior returned for twelve months soon after, to lead a small group including Lemmon, Peter Geach and Ivo Thomas (Copeland 2004). John Lemmon became one of the early champions of Prior's distinctive approach to tense logic , and Lemmon's later work on alethic modality and applications of modal logic to ethics bear the mark of Prior's influence. At this time, Lemmon published a treatment of alethic and epistemic modalities that introduced some systems of non- normal modal logics that have proven to have had lasting interest, the alethic system S0.5 and the epistemic systems E1–E5 linked to the systems S0.5 and Lewis's systems S2–S5, but which lack the law of necessitation (Lemmon 1957).
Lemmon was a pioneer of the modern approach to the semantics of modal logic, particularly through his collaboration with Dana Scott , but also became interested in the rival algebraic semantics of modal logic that follows more closely the kind of semantics found in the work of Tarski and Jónsson . | https://en.wikipedia.org/wiki/John_Lemmon |
Sir John Edward Lennard-Jones KBE , FRS [ 1 ] (27 October 1894 – 1 November 1954) was a British mathematician and professor of theoretical physics at the University of Bristol , and then of theoretical science at the University of Cambridge . He was an important pioneer in the development of modern computational chemistry and theoretical chemistry . [ 3 ] [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ] [ 12 ]
Lennard-Jones was born John Edward Jones on 27 October 1894 at Leigh , Lancashire, the eldest son of Mary Ellen and Hugh Jones, an insurance agent. He was educated at Leigh Grammar School, going on to study at the University of Manchester , graduating in 1915 with a first-class honours degree in mathematics. [ 13 ] Following service with the Royal Flying Corps during World War I , where he trained as a pilot, he studied for a Doctorate of Science (DSc) degree in Mathematics at Manchester, graduating in 1922. On the advice of Sydney Chapman , he then successfully applied for a Senior 1851 Exhibition at Trinity College, Cambridge , where he was supervised by Ralph H. Fowler and graduated with a second doctorate in 1924.
Lennard-Jones is well known among scientists for his work on molecular structure , valency and intermolecular forces . Much research of these topics over several decades grew from a paper he published in 1929. [ 6 ] His theories of liquids and of surface catalysis also remain influential. He wrote few, albeit influential, papers.
His main interest was of atomic and molecular structure, especially the forces between atomic particles, the nature of chemical bonds and such basic matters as why water expands when it freezes. Holding the first Chair of Theoretical Chemistry in the United Kingdom (at the University of Cambridge ), he established a research school applying to phenomena in physics and organic chemistry new concepts of quantum mechanics and the interactions of subatomic particles. The department attracted many notable scientists and mathematicians, including S.F. Boys , C.A. Coulson , G.G. Hall , A. Hurley, and J. Pople .
Atoms of a noble gas interact via a potential in which an attracting van der Waals force balances a repelling force which results from overlapping electron orbits. A well-known approximation to this potential is the so-called Lennard-Jones potential , [ 14 ] [ 15 ] a description of the potential energy as a function of the separation of the atoms. Also named after him, the Lennard-Jones Laboratory houses the School of Chemistry and Physics at Keele University . The Royal Society of Chemistry awards a Lennard-Jones Medal [ 16 ] and hosts the Lennard-Jones lecture every second year.
Keele University holds a collection of Lennard-Jones's published work, as well as a laboratory named in his honour. Professor C.A. Coulson's collected lecture notes from 1928 to 1932, held in Cambridge University Library , record Lennard-Jones' lectures. Coulson wrote 'I suspect that these are the first lectures on theoretical chemistry (or perhaps more accurately quantum chemistry ) that had been given in Britain'. Lennard-Jones's private papers are held at Churchill Archives Centre , in Cambridge. [ 17 ]
On 26 August 1925 he married Kathleen Mary Lennard, and added her surname to his own to become Lennard-Jones. The couple had two children, John and Mary. He died of cancer at Stoke-on-Trent on 1 November 1954. [ 13 ]
The Lennard-Jones Centre [ 19 ] at the University of Cambridge is named in his honour.
The school of chemistry/medicinal chemistry and physics at Keele university is named after him. | https://en.wikipedia.org/wiki/John_Lennard-Jones |
John Randolph Lucas FBA (18 June 1929 – 5 April 2020) [ 1 ] was a British philosopher .
Lucas was educated at Winchester College and then, as a pupil of R.M. Hare , among others, at Balliol College, Oxford . [ 2 ] He studied first mathematics, then Greats (Greek, Latin, Philosophy and Ancient History), obtaining first class honours in both. He sat for Finals in 1951, and took his MA in 1954. He spent the 1957–58 academic year at Princeton University , studying mathematics and logic. For 36 years, until his 1996 retirement, he was a Fellow and Tutor of Merton College, Oxford , and he remained an emeritus member of the University Faculty of Philosophy. He was a Fellow of the British Academy . [ 3 ]
Lucas is perhaps best known for his paper " Minds, Machines and Gödel ," arguing that an automaton cannot represent a human mathematician, attempting to refute computationalism .
An author with diverse teaching and research interests, Lucas wrote on the philosophy of mathematics , especially the implications of Gödel's incompleteness theorem , the philosophy of mind , free will and determinism , the philosophy of science including one book on physics co-authored with Peter E. Hodgson , causality , political philosophy , ethics and business ethics , and the philosophy of religion .
The son of a Church of England clergyman, and an Anglican himself, Lucas described himself as "a dyed-in-the-wool traditional Englishman." He had four children ( Edward , Helen , Richard and Deborah) with Morar Portal, among them Edward Lucas , a former journalist at The Economist .
In addition to his philosophical career, Lucas had a practical interest in business ethics . He helped found the Oxford Consumers' Group, [ 4 ] and was its first chairman in 1961–3, serving again in 1965.
Lucas (1961) began a lengthy and heated debate over the implications of Gödel's incompleteness theorems for the anthropic mechanism thesis , by arguing that: [ 5 ]
His argument was strengthened by the discovery by Hava Siegelmann in the 1990s that sufficiently complex analogue recurrent neural networks are more powerful than Turing Machines . [ 6 ]
Lucas wrote several books on the philosophy of science and space-time (see below). In A treatise on time and space [ 7 ] he introduced a transcendental derivation of the Lorenz Transformations based on Red and Blue exchanging messages (in Russian and Greek respectively) from their respective frames of reference which demonstrates how these can be derived from a minimal set of philosophical assumptions.
In The Future Lucas gives a detailed analysis of tenses and time, arguing that "the Block universe gives a deeply inadequate view of time. It fails to account for the passage of time, the pre-eminence of the present, the directedness of time and the difference between the future and the past" [ 8 ] and in favour of a tree structure in which there is only one past or present (at any given point in spacetime) but a large number of possible futures. "We are by our own decisions in the face of other men's actions and chance circumstances weaving the web of history on the loom of natural necessity" [ 9 ] | https://en.wikipedia.org/wiki/John_Lucas_(philosopher) |
John Macadam (29 May 1827 – 2 September 1865), was a Scottish - Australian chemist , medical teacher, Australian politician and cabinet minister, and honorary secretary of the Burke and Wills expedition . The genus Macadamia (macadamia nut) was named after him in 1857. He died at sea, on a voyage from Australia to New Zealand, aged 38.
John Macadam was born at Northbank, Glasgow , Scotland , on 29 May 1827, [ 1 ] the son of William Macadam (1783-1853) and Helen, née Stevenson (1803-1857). [ 2 ] His father was a Glasgow businessman, who owned a spinning and textile printing works in Kilmarnock , and was a burgess and a bailie (magistrate) of Glasgow. [ 3 ] His fellow industrialists and he in the craft had developed, using chemistry, the processes for the large-scale industrial printing of fabrics for which these plants in the area became known. [ 4 ]
John Macadam was privately educated in Glasgow; he studied chemistry at the Andersonian University (now the University of Strathclyde ) and went for advanced study at the University of Edinburgh under Professor William Gregory . In 1846–47, he went on to serve as assistant to Professor George Wilson at the University of Edinburgh in his laboratory in Brown Square. [ 5 ] He was elected a fellow of the Royal Scottish Society of Arts that year, and in 1848, a member of the Glasgow Philosophical Society. He then studied medicine at the University of Glasgow (LFPS, MD,1854; FFPSG,1855). [ 6 ]
He was a member of what became a small dynasty of Scottish scientists and lecturers in analytical chemistry, which included, other than himself, his eldest half brother William Macadam, his immediate younger brother Stevenson Macadam (a younger brother Charles Thomas Macadam, [ 7 ] although not involved as a scientist, was also indirectly involved in chemistry becoming a senior partner in a chemical fertiliser company) [ 8 ] and nephews William Ivison Macadam and Stevenson J. C. G. Macadam, [ 9 ] as well as the former nephew's daughter, his great niece Elison A. Macadam. [ 10 ]
On 8 June 1855, aged 28, Macadam sailed for Melbourne in the Colony of Victoria , Australia, on the sailing ship Admiral. He arrived on 8 September 1855. [ 11 ] [ 12 ]
In 1855 he was a lecturer on chemistry and natural science at Scotch College , having been engaged for the position before leaving Scotland. [ 13 ]
In 1857 he was awarded an MD ad eundem from the University of Melbourne in acknowledgment of his MD from the University of Glasgow. [ 14 ]
In 1857-1858 he also taught at Geelong Church of England Grammar School (now Geelong Grammar School ). [ 15 ] In 1858, he was appointed the Victorian government analytical chemist. [ 16 ] In 1860 he became health officer to the City of Melbourne . He wrote several reports on public health. [ 17 ]
On 3 March 1862 he was appointed as the first lecturer in medicine (chemistry and practical chemistry) at the University of Melbourne School of Medicine . For the next few years he held classes for a small number of medical students in the Analytical Laboratory behind the Public Library. [ 18 ] [ 19 ] He was also a member of the Board of Agriculture. [ 20 ]
Macadam became a member of the Victorian Legislative Assembly of the self-governing Colony of Victoria [ 21 ] as a radical and supporter of the Land Convention, [ 22 ] representing Castlemaine .
Appointed postmaster-general of Victoria in 1861, [ 23 ] [ 22 ] Macadam resigned from the legislature in 1864. He had sponsored bills on medical practitioners and adulteration of food which became law in 1862 and 1863. [ 22 ]
Between 1857 and 1862, Macadam served as honorary secretary of the Philosophical Institute of Victoria , which then became the Royal Society of Victoria in 1860, [ 24 ] and was appointed vice-president of it in 1863. He was editor of first five volumes of the society's Transactions . [ 25 ] He was active in erecting the Society's Meeting Hall (their present building) [ 26 ] and was involved in the institute's initiative to obtain a royal charter. He saw both happen while he held office, when in January 1860, the Philosophical Institute became the Royal Society of Victoria and met in their new building. [ 27 ] [ 28 ]
Between 1857 and 1865, Macadam served as honorary secretary to the Exploration Committee of the Royal Society of Victoria, which organised the Burke and Wills expedition .
The expedition was organised by the society with the aim of crossing the continent of Australia from the south to the north coasts, map it, and collect scientific data and specimens. At that time, most of the interior of Australia had not been explored by the European settlers and was unknown to them.
In 1860–61, Robert O'Hara Burke and William John Wills led the expedition of 19 men with that intention, crossing Australia from Melbourne in the south, to the Gulf of Carpentaria in the north, a distance around 2,000 miles.
Three men ultimately travelled over 3,000 miles from Melbourne to the shores of the Gulf of Carpentaria and back to the Depot Camp at Cooper Creek . Seven men died in the attempt, including the leaders Burke and Wills. Of the four men who reached the north coast, only one, John King , survived with the help of the indigenous people to return to Melbourne. [ 29 ]
This expedition became the first to cross the Australian continent. It was of great importance to the subsequent development of Australia and could be compared in importance to the Lewis and Clark Expedition overland to the North American Pacific Coast to the development of the United States. [ 30 ]
After the heavy death toll of the expedition, initial criticism fell on the Royal Society, but it became clear that their foresight could not have prevented the deaths and this was then widely recognised [ 31 ] when it became known that as Secretary of the Exploration Committee of the Burke and Wills expedition, Dr. Macadam had insisted on adequate provisions for their safety. [ 32 ]
The macadamia (genus Macadamia ) nut was discovered by the European settlers, [ 33 ] and subsequently the tree was named after him by his friend and colleague, Ferdinand von Mueller (1825-1896), [ 34 ] Director of the Royal Botanic Gardens, Melbourne . [ 35 ] The tree gave his name to macadamia nuts . The genus Macadamia was first described scientifically in 1857 by Dr. Mueller and he named the new genus in honour of his friend Dr John Macadam. Mueller had done a great deal of taxonomy of the flora, naming innumerable genera but chose this "...a beautiful genus dedicated to John Macadam, M.D. the talented and deserving secretary of our institute." [ 36 ]
On 7 August 1858, Macadam, along with Tom Wills , officiated at a game of football played between Scotch College and Melbourne Grammar . This game was a predecessor to the modern game of Australian rules football and is commemorated by a statue outside the Melbourne Cricket Ground . [ 37 ]
The two schools have competed annually ever since, lately for the Cordner–Eggleston Cup. [ 38 ]
On 18 September 1856, a year after he arrived from Scotland, he married Elizabeth Clark in Melbourne, Australia. [ 44 ] She had arrived three days before the wedding with her maid on the Admiral , the same ship on which he had travelled out a year earlier, which reached Hobson's Bay (Melbourne's port) on 15 September 1856, having set sail from London on 7 June 1856. [ 45 ] Elizabeth Clark was probably born on 7 October 1832 in Barony parish Scotland, near Glasgow (her mother being Mary McGregor). She was the second daughter of John Clark, [ 46 ] of Levenfield House in Alexandria, [ 47 ] the Vale of Leven, a short distance north of Glasgow in West Dunbartonshire. [ 48 ] His Levenfield Works were involved in similar work to Dr John Macadam's father William Macadam in Kilmarnock in the then lucrative business of textile printing for domestic and European markets. The Clarks and Macadams must have become known to each other in Scotland because of their respective fathers' business connections. Elizabeth died in 1915, in Brighton, Victoria. [ 49 ]
John and Elizabeth had two sons:
John Melnotte Macadam was born 29 August 1858 at Fitzroy, Melbourne, Australia, and died on 30 January 1859, [ 50 ] aged 5 months (he was reburied with his father, whose monument bears the additional inscription: In memory of his only children John Melnotte Macadam Born August 29, 1858 Died January 30, 1859 followed by an inscription to his second son below it). [ 51 ]
William Castlemaine Macadam was born on 2 July 1860 and died 17 December 1865 [ 52 ] at Williamstown, Victoria, Australia. He died aged five and had survived his father by a few months. [ 53 ] The inscription on his father's burial monument under His only children has him listed under his elder brother (above), who died in infancy, but does not for some reason give William's date of death on it. [ 54 ]
In March 1865 Macadam sailed to New Zealand to give evidence at the trial of Captain W. A. Jarvey, accused of fatally poisoning his wife, but the jury did not reach a verdict. [ 55 ] During the return voyage, Macadam fractured his ribs during a storm. He was advised, on medical grounds, not to return for the adjourned trial but did so and died on the ship on 2 September 1865. His medical-student assistant John Drummond Kirkland gave evidence at the trial in Macadam's place, and Jarvey was convicted. [ 56 ] [ 57 ]
The Australian News commented, "At the time of his death, Dr Macadam was but 38 years of age; there can be little doubt that the various and onerous duties he discharged for the public must be attributed in great measure the shortening of his days." [ 58 ] The Australian Medical Journal stated, "For some time it had been evident to his friends that his general health was giving way: that a frame naturally robust and vigorous was gradually becoming undermined by the incessant and harassing duties of the multifarious offices he filled." The inquest verdict (he died at sea) stated, "His death was caused by excessive debility and general exhaustion." [ 59 ]
The funeral was large. The newspapers carried tributes and subsequently lengthier obituaries from learned societies were published, such as that in the Australian Medical Journal [ 60 ] and elsewhere. The Melbourne Leader described the funeral: "The coffin was drawn by four horses. Four mourning coaches contained the chief mourners and the more intimate friends of the deceased gentleman. A large procession followed, in which were several members of Parliament, the members of the Royal Society, the Chief Justice; the Mayor and corporation of the city of Melbourne. A number of private carriages and the public wound up the procession....At the University, the chancellor, the vice-chancellor, and a number of the students, all in their academic robes, met the funeral cortege, and proceeded the remainder of the distance". [ 61 ] The chief mourner was his youngest brother, George Robert Macadam (1837-1918). [ 62 ] John Macadam's grave, surmounted by a marble obelisk, is in Melbourne General Cemetery . [ 63 ]
After John Macadam and her children's deaths his widow, Elizabeth Clark, later remarried. She married the Reverend John Dalziel Dickie, who was pastor at Colac for 32 years. They married on 26 February 1868 [ 64 ] They had four daughters. [ 65 ] Elizabeth Dickie died aged 82 in 1915, in Brighton, Victoria , as the widow of the Rev. Dickie. [ 66 ] Dickie had died 25 December 1909. [ 67 ]
Hartog, Philip Joseph (1893). "Macadam, John" . In Lee, Sidney (ed.). Dictionary of National Biography . Vol. 34. London: Smith, Elder & Co. | https://en.wikipedia.org/wiki/John_Macadam |
John Henry McDowell FBA (born 7 March 1942) is a South African philosopher , formerly a fellow of University College, Oxford , and now university professor at the University of Pittsburgh . Although he has written on metaphysics , epistemology , ancient philosophy , nature , and meta-ethics , McDowell's most influential work has been in the philosophy of mind and philosophy of language . McDowell was one of three recipients of the 2010 Andrew W. Mellon Foundation's Distinguished Achievement Award, [ 8 ] and is a Fellow of both the American Academy of Arts & Sciences and the British Academy .
McDowell has, throughout his career, understood philosophy to be "therapeutic" and thereby to "leave everything as it is" ( Ludwig Wittgenstein , Philosophical Investigations ), which he understands to be a form of philosophical quietism (although he does not consider himself to be a "quietist"). The philosophical quietist believes that philosophy cannot make any explanatory comment about how, for example, thought and talk relate to the world but can, by offering re-descriptions of philosophically problematic cases, return the confused philosopher to a state of intellectual perspicacity.
However, in defending this quietistic perspective McDowell has engaged with the work of leading contemporaries in such a way as to therapeutically dissolve what he takes to be philosophical error, while defending major positions and interpretations from major figures in philosophical history, and developing original and distinctive theses about language, mind and value. In each case, he has tried to resist the influence of what he regards as a scientistic , reductive form of philosophical naturalism that has become very commonplace in our historical moment, while nevertheless defending a form of "Aristotelian naturalism, [ 9 ] " bolstered by key insights from Hegel , Wittgenstein, and others.
McDowell was born in Boksburg , South Africa and completed a B.A. at the University College of Rhodesia and Nyasaland . In 1963, he moved to New College , Oxford as a Rhodes scholar , where he earned another B.A. in 1965 and an M.A. in 1969. [ 10 ] He taught at University College, Oxford , from 1966 until 1986, when he joined the faculty at the University of Pittsburgh , where he is now a University Professor. He has also been a visiting professor at many universities, including Harvard University , University of Michigan , and University of California, Los Angeles .
McDowell was elected a Fellow of the British Academy in 1983 [ 11 ] and a Fellow of the American Academy of Arts and Sciences in 1992. [ 12 ] In 2010 he received the Andrew W. Mellon Foundation Distinguished Achievement Award in the Humanities. [ 13 ]
McDowell delivered the John Locke Lectures in Philosophy at Oxford University in 1991 (these became his book Mind and World .) [ 14 ] He has also given the Woodbridge Lectures at Columbia University in 1997 [ 15 ] and the Howison Lectures in Philosophy at the University of California at Berkeley in 2006. [ 16 ]
He received an honorary degree from the University of Chicago in 2008. [ 17 ]
McDowell's earliest published work was in ancient philosophy, most notably including a translation of and commentary on Plato 's Theaetetus . In the 1970s he was active in the Davidsonian project of providing a semantic theory for natural language , co-editing (with Gareth Evans ) a volume of essays entitled Truth and Meaning . McDowell edited and published Evans's influential posthumous book The Varieties of Reference (1982).
In his early work, McDowell was very much involved both with the development of the Davidsonian semantic programme and with the internecine dispute between those who take the core of a theory that can play the role of a theory of meaning to involve the grasp of truth conditions, and those, such as Michael Dummett , who argued that linguistic understanding must, at its core, involve the grasp of assertion conditions. If, Dummett argued, the core of a theory that is going to do duty for a theory of a meaning is supposed to represent a speaker's understanding, then that understanding must be something of which a speaker can manifest a grasp. McDowell argued, against this Dummettian view and its development by such contemporaries as Crispin Wright , both that this claim did not, as Dummett supposed, represent a Wittgensteinian requirement on a theory of meaning and that it rested on a suspect asymmetry between the evidence for the expressions of mind in the speech of others and the thoughts so expressed. This particular argument reflects McDowell's wider commitment to the idea that, when we understand others, we do so from "inside" our own practices: Wright and Dummett are treated as pushing the claims of explanation too far and as continuing W. V. O. Quine 's project of understanding linguistic behaviour from an "external" perspective.
In these early exchanges and in the parallel debate over the proper understanding of Wittgenstein's remarks on rule-following, some of McDowell's characteristic intellectual stances were formed: to borrow a Wittgensteinian expression, the defence of a realism without empiricism, an emphasis on the human limits of our aspiration to objectivity, the idea that meaning and mind can be directly manifested in the action, particularly linguistic action, of other people, and a distinctive disjunctive theory of perceptual experience.
The latter is an account of perceptual experience, developed at the service of McDowell's realism, in which it is denied that the argument from illusion supports an indirect or representative theory of perception as that argument presupposes that there is a "highest common factor" shared by veridical and illusory (or, more accurately, delusive) experiences. (There is clearly a distinction between perceiving and acquiring a belief: one can see an "apparently bent" stick in the water but not believe that it is bent as one knows that one's experience is illusory. In illusions, you need not believe that things are as the illusory experiences represent them as being; in delusions, a person believes what their experience represents to them. So the argument from illusion is better described as an argument from delusion if it is to make its central point.)
In the classic argument from illusion (delusion) you are asked to compare a case where you succeed in perceiving, say, a cat on a mat, to the case where a trick of light deceives you and form the belief that the cat is on the mat, when it is not. The proponent of the argument then says that the two states of mind in these contrasting cases share something important in common, and to characterise this we need to introduce an idea like that of "sense data." Acquaintance with such data is the "highest common factor" across the two cases. That seems to force us into a concession that our knowledge of the external world is indirect and mediated via such sense data. McDowell strongly resists this argument: he does not deny that there is something psychologically in common between the subject who really sees the cat and the one that fails to do so. But that psychological commonality has no bearing on the status of the judger's state of mind from the point of view of assessing whether she is in a position to acquire knowledge. In favourable conditions, experience can be such as to make manifest the presence of objects to observers – that is perceptual knowledge. When we succeed in knowing something by perceiving it, experience does not fall short of the fact known. But this just shows that a successful and a failed perceptual thought have nothing interesting in common from the point of view of appraising them as knowledge.
In this claim that a veridical perception and a non-veridical perception share no highest common factor, a theme is visible which runs throughout McDowell's work, namely, a commitment to seeing thoughts as essentially individuable only in their social and physical environment, so called externalism about the mental. McDowell defends, in addition to a general externalism about the mental, a specific thesis about the understanding of demonstrative expressions as involving so-called "singular" or "Russellian" thoughts about particular objects that reflects the influence on his views of Gareth Evans. According to this view, if the putative object picked out by the demonstrative does not exist, then such an object dependent thought cannot exist – it is, in the most literal sense, not available to be thought.
In parallel with the development of this work on mind and language, McDowell also made significant contributions to moral philosophy, specifically meta-ethical debates over the nature of moral reasons and moral objectivity. McDowell developed the view that has come to be known as secondary property realism, or sensibility or moral sense theory . The theory proceeds via the device of an ideally virtuous agent: such an agent has two connected capacities. She has the right concepts and the correct grasp of concepts to think about situations in which she finds herself by coming to moral beliefs. Secondly, for such a person such moral beliefs are automatically over-riding over other reasons she may have and in a particular way: they "silence" other reasons, as McDowell puts it. He believes that this is the best way to capture the traditional idea that moral reasons are specially authoritative.
McDowell rejects the Humean theory that every intentional action is the result of a combination of a belief and a desire, with the belief passively supplying a representation and the desire supplying the motivation. McDowell, following Thomas Nagel , holds that the virtuous agent's perception of the circumstances (i.e. her belief) justifies both the action and the desire. In order to understand the desire, we must understand the circumstances that the agent experienced and that compelled her to act. So, while the Humean thesis may be true about explanation, it is not true about the structure of justification— it should be replaced by Nagel's motivated desire theory . [ 18 ]
Implicit in this account is a theory of the metaphysical status of values: moral agents form beliefs about the moral facts, which can be straightforwardly true or false. However, the facts themselves, like facts about colour experience, combine anthropocentricity with realism. Values are not there in the world for any observer, for example, one without our human interest in morality. However, in that sense, colours are not in the world either, but one cannot deny that colours are both present in our experience and needed for good explanations in our common sense understanding of the world. The test for the reality of a property is whether it is used in judgements for which there are developed standards of rational argument and whether they are needed to explain aspects of our experience that are otherwise inexplicable. McDowell thinks that moral properties pass both of these tests. There are established standards of rational argument and moral properties fall into the general class of those properties that are both anthropocentric but real.
The connection between McDowell's general metaphysics and this particular claim about moral properties is that all claims about objectivity are to be made from the internal perspective of our actual practices, the part of his view that he takes from the later Wittgenstein. There is no standpoint from outside our best theories of thought and language from which we can classify secondary properties as "second grade" or "less real" than the properties described, for example, by a mature science such as physics. Characterising the place of values in our worldview is not, in McDowell's view, to downgrade them as less real than talk of quarks or the Higgs boson.
McDowell's later work reflects the influence of G. W. F. Hegel , P. F. Strawson , Robert Brandom , Richard Rorty , and Wilfrid Sellars ; both Mind and World and the Woodbridge lectures focus on a broadly Kantian understanding of intentionality (the mind's capacity to represent). Influenced by Sellars's famous diagnosis of the " Myth of the Given " in traditional empiricism, [ nb 1 ] McDowell's goal in Mind and World is to explain how we are passive in our perceptual experience of the world but active in conceptualizing it. In his account, he tries to avoid any connection with idealism, and develops an account of what Kant called the "spontaneity" of our judgement in perceptual experience.
Mind and World rejects a reductively naturalistic account: what McDowell calls "bald naturalism." He contrasts this with his own "naturalistic" perspective in which the distinctive capacities of mind are a cultural achievement of our "second nature", an idea that he adapts from Gadamer . The book concludes with a critique of Quine 's narrow conception of empirical experience and also a critique of Donald Davidson 's view of beliefs as being answerable only to other beliefs, in which Davidson plays the role of the pure coherentist .
In his later work, McDowell denies that there is any philosophical use for the idea of nonconceptual content — the idea that our experience contains representations that are not conceptually structured. Starting with a careful reading of Sellars's Empiricism and the Philosophy of Mind , he argues that we need to separate the use of concepts in experience from a causal account of the preconditions of experience. He argues that the idea of "nonconceptual content" is philosophically unacceptable because it straddles the boundary between these two. This denial of nonconceptual content has provoked considerable discussion because other philosophers have claimed that scientific accounts of our mental lives (particularly in cognitive science ) need this idea.
While Mind and World represents an important contemporary development of a Kantian approach to philosophy of mind and metaphysics, one or two of the uncharitable interpretations of Kant's work in that book receive important revisions in McDowell's later Woodbridge Lectures, published in the Journal of Philosophy , Vol. 95, 1998, pp. 431–491. Those lectures are explicitly about Wilfrid Sellars, and assess whether or not Sellars lived up to his own critical principles in developing his interpretation of Kant (McDowell claims not). McDowell has, since the publication of Mind and World, largely continued to reiterate his distinctive positions that go against the grain of much contemporary work on language, mind, and value, particularly in North America where the influence of Wittgenstein has significantly waned.
McDowell's work has been heavily influenced by, among others, Aristotle , Immanuel Kant , G. W. F. Hegel , Karl Marx , John Cook Wilson , [ 20 ] Ludwig Wittgenstein , Hans-Georg Gadamer , Philippa Foot , [ 21 ] Elizabeth Anscombe , [ 22 ] P. F. Strawson , Iris Murdoch , [ 23 ] David Wiggins , and, especially in the case of his later work, Wilfrid Sellars . Many of the central themes in McDowell's work have also been pursued in similar ways by his Pittsburgh colleague Robert Brandom (though McDowell has stated strong disagreement with some of Brandom's readings and appropriations of his work). Both have been influenced by Richard Rorty , in particular Rorty's Philosophy and the Mirror of Nature (1979). In the preface to Mind and World (pp. ix–x) McDowell states that "it will be obvious that Rorty's work is [...] central for the way I define my stance here." | https://en.wikipedia.org/wiki/John_McDowell |
John Edward McGinness (born November 19, 1943), is an American physicist and physician . McGinness worked in the fields of organic electronics and nanotechnology .
McGinness studied physics at the University of Houston , and after his B.S. in 1966 he received his PhD in Nuclear Physics, Material Science, and Space Science at Rice University in 1970. [ 1 ]
He received his MD from the University of Texas Health Science Center at Houston (UTHealth) in 1985 and worked in internal medicine for one year, changing to psychiatry and working at the Department of Psychiatry, UTHealth, from 1989 to 1992. He authored roughly 40 research publications, book chapters, and presentations.
John McGinness materially contributed to the modern field of organic electronics . [ 2 ]
In 1972, while working at the Metallurgy department at Youngstown State University , McGinness suggested that electronic conduction in melanins ( polyacetylene , polypyrrole , and polyaniline "blacks" and their copolymers) is analogous to conduction in amorphous solids such as the chalcogenide glasses . [ 4 ] This area was originally pioneered by Sir Nevill Mott , among others. That is, it involves such things as mobility gaps, phonon -assisted hopping, polarons , quantum tunneling , and so forth.
From Youngstown, McGinness moved to the Physics Department of The University of Texas M. D. Anderson Cancer Center . The department had an interest in the physical properties of melanin as a possible hook to treating melanoma . While of enormous importance now, this area was a research backwater at the time. With the notable exception of Bolto et al. , who had reported [ 5 ] high conductivity in iodine-doped polypyrrole , [ 5 ] few but melanoma researchers had much reason to look at the electronic properties of such rigid-backbone polymer "blacks". This is why the putative first molecular electronic device came from a cancer hospital.
The chalcogenide glasses show "switching", in which an applied "threshold voltage" reversibly switches a material from a low-conductivity "OFF" state to a high-conductivity "ON' state. The similarity of conduction mechanisms suggested that the melanins might also demonstrate voltage-controlled switching. Following this lead, McGinness and his MD Anderson coworkers constructed a voltage-controlled switch incorporating melanin as its active element . [ 6 ] They also further characterized its electronic behavior. [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ] [ 12 ]
Since he was at a cancer research institute, McGinness' other interests included the role of free radicals in the action and toxicity of the anticancer drugs cisplatin , adriamycin , and bleomycin . He was the first to show that the kidney toxicity of cisplatin involves reactive oxygen species . [ 2 ] Some of this work was done with Harry Demopoulos . McGinness was also involved in the dielectric spectroscopy of water bound to membranes. [ 13 ] This was related to the future development of magnetic resonance imaging . | https://en.wikipedia.org/wiki/John_McGinness |
John Michael Ramsey is an American analytical chemist at the University of North Carolina at Chapel Hill . He currently holds the position of Minnie N. Goldby Distinguished Professor of Chemistry. [ 1 ] His current research with the university focuses on microscale and nanoscale devices such as microchip electrospray , microscale Ion trap mass spectrometers , and microfluidic point of care devices. [ 2 ] He is ranked #2 in the "Giants of Nano" field on The Analytical Scientist Power List. [ 3 ]
Michael Ramsey attended Bowling Green State University for his undergraduate studies where he obtained his Bachelor of Science in Chemistry with dual minors in Physics and Mathematics in June 1974. [ 4 ]
He then went on to obtain his Doctor of Philosophy in Analytical chemistry from Indiana University Bloomington in January 1979. Dr. Ramsey conducted his research under the direction of Gary M. Hieftje from 1974 to 1979 culminating in his published dissertation "New Approaches for the Measurement of Subnanosecond Chemical Phenomena" [1] . [ 4 ]
The Ramsey Group at the University of Chapel Hill is interested in utilizing micro- and nano fabrication strategies to create devices that facilitate people's ability to gather chemical and biochemical information. Their motivations for fabricating devices include clinical diagnostics, high-throughput biochemical experimentation, understanding of transport mechanisms in nanoscale -confined spaces, and development of portable mass spectrometers operating at high-pressures (>1 Torr).
Applications for the devices that they develop include drug discovery , health care , environmental monitoring , chemical process control, and high-throughput laboratory analysis and basic research.
The four main areas of active research in the Ramsey group include:
He is a founding scientist and current director of 908 Devices incorporated, [ 5 ] a company which focuses on building handheld mass spectrometry devices for applications in laboratory analysis, safety and security, as well as for use in the life sciences. [ 6 ] In 2017 908 Devices Inc. received the Federal Laboratory Consortium Excellence in Technology Transfer Award. [ 4 ] The company is known for several products, including the zipchip ™ separations platform for quick and high quality separation and mass spectrometry analysis of biological samples and the M908 ™ handheld High Pressure Mass Spectrometry tool for analysis of chemical warfare agents. [ 6 ] Dr. Ramsey is also a founding scientist and former scientific advisory board member of Caliper Technologies incorporated, later renamed Caliper Life Sciences , a company that commercializes microfluidics and lab-on-a-chip technologies. [ 4 ] Caliper Life Sciences was acquired by PerkinElmer in 2011 for $650M. [ 6 ]
Between 1979 and 2004, Ramsey worked as a Eugene P. Wigner Fellow, research associate, and eventually a group leader for Oak Ridge National Laboratory . [ 4 ] [ 7 ]
Awards that Ramsey has received include the Ralph N. Adams Award in Bioanalytical Chemistry (2013), [ 8 ] the CASSS Award for Outstanding Achievements in Separation Science (2012), [ 9 ] the American Chemical Society Award in Chromatography (2007), [ 10 ] the Pittsburgh Analytical Chemistry Award (2006), [ 11 ] the ACS Division of Analytical Chemistry Award in Chemical Instrumentation (2003), [ 12 ] [ 13 ] the Battelle Distinguished Inventor Award (2003), [ 13 ] and the Frederick Conference Capillary Electrophoresis Award (2000). [ 4 ] [ 14 ]
Ramsey holds professional memberships with National Academy of Engineering , the American Chemical Society , and the Analytical Division of the American Chemical Society . [ 4 ]
He has 108 issues patents, 2 allowed patents, and 20 pending patents. [ 4 ] | https://en.wikipedia.org/wiki/John_Michael_Ramsey |
John Alexander Reina Newlands (26 November 1837 – 29 July 1898) was a British chemist who worked concerning the periodicity of elements. [ 1 ]
Newlands was born in London in England, at West Square in Southwark , the son of a Scottish Presbyterian minister and his Italian wife. [ 2 ]
Newlands was home-schooled by his father, and later studied at the Royal College of Chemistry , now part of Imperial College London . He was interested in social reform and during 1860 served as a volunteer with Giuseppe Garibaldi in his military campaign to unify Italy. [ 3 ] Returning to London, Newlands established himself as an analytical chemist in 1864. In 1868 he became chief chemist of James Duncan's London sugar refinery , where he introduced a number of improvements in processing. Later he quit the refinery and again became an analyst with his brother, Benjamin.
Newlands was the first person to devise a periodic table of chemical elements arranged in order of their relative atomic masses [ 4 ] published in Chemical News in February 1863. [ 3 ] [ 5 ] Continuing Johann Wolfgang Döbereiner 's work with triads and Jean-Baptiste Dumas ' families of similar elements, he published in 1865 his " Law of Octaves ", which stated that "any given element will exhibit analogous behaviour to the eighth element following it in the table." Newlands arranged all of the known elements, starting with hydrogen and ending with thorium (atomic weight 232), into eight groups of seven, which he likened to octaves of music . [ 6 ] [ 7 ] In Newlands' table, the elements were ordered by the atomic weights that were known at the time and were numbered sequentially to show their order. Groups were shown going across the table, with periods going down – the opposite from the modern form of the periodic table.
The incompleteness of the table alluded to the possible existence of additional, undiscovered elements. However, the Law of Octaves was ridiculed by some of Newlands' contemporaries, and the Society of Chemists did not accept his work for publication. [ 8 ]
After Dmitri Mendeleev and Lothar Meyer received the Davy Medal from the Royal Society for their later 'discovery' of the periodic table in 1882, Newlands fought for recognition of his earlier work and eventually received the Davy Medal in 1887.
John Newlands died due to complications of surgery at his home in Lower Clapton , Middlesex and was buried at West Norwood Cemetery . His businesses was continued after his death by his younger brother, Benjamin. | https://en.wikipedia.org/wiki/John_Newlands_(chemist) |
John Scott Newman (born November 17, 1938) is an American retired academic.
A professor and renowned battery and electrochemical engineer researcher, he worked at the University of California in the Department of Chemical Engineering. The Newman Research Group was established with the goal of identifying "efficient and economical methods for electrochemical energy conversion and storage, development of mathematical models to predict the behavior of electrochemical systems and to identify important process parameters, and experimental verification of the completeness and accuracy of the models". [ 1 ]
Newman also worked for the Electrochemical Technologies Group at Lawrence Berkeley National Laboratory [ 2 ] where he was a Faculty Senior Scientist. [ 3 ] While at LBNL he served as director of several Department of Energy ’s energy storage programs, including the Batteries for Advanced Transportation Technologies Program. [ 4 ] He was elected a member of the National Academy of Engineering in 1999 for contributions to applied electrochemistry and for their reduction to practice through advances in electrochemical engineering. He was an Onsager Professor at the Norwegian University of Science and Technology in 2002. [ 4 ] Newman is regarded by many as "the father of electrochemical engineering." [ 5 ] The Newman Method is a "numerical technique...developed for solving coupled electrochemical reaction–diffusion equations". [ 6 ] [ 4 ]
Professor Newman has authored more than 339 scientific publications, with more the 47000 citations, and an h-index of 95. He is the author of Electrochemical Systems with Karen E. Thomas-Alyea which is "used throughout the world as a monograph and graduate text in electrochemical engineering." [ 4 ]
In 2010 he received the Edward Goodrich Acheson Award of the Electrochemical Society , his tenth award from the society. [ 4 ]
Newman has graduated thirty masters and forty-three Ph.D. students and seventeen have gone on to become faculty members as of 2008. [ 7 ] The faculty include Thomas W. Chapman (Ph.D., 1967), Kemal Nisancioglu (Ph.D. 1973), Nader Vahdat (MS, 1972), Peter Willem Appel (Ph.D. 1976), Ralph Edward White (PhD, 1977), Peter S. Fedkiw (Ph.D., 1978), James Arthur Trainham, III (Ph.D., 1979), Richard Pollard (Ph.D., 1979), Mark Edward Orazem (Ph.D., 1983), Michael John Matlosz (Ph.D., 1985), Alan C. West (Ph.D., 1989), Thomas F. Fuller (Ph.D., 1992), Bavanethan Pillay (Ph.D., 1996), Jeremy Patrick Meyers (Ph.D., 1998), Heather Darya Yaros (Ph.D., 2002), Dean Richard Wheeler (Ph.D., 2002), Charles Monroe (Ph.D., 2004), Paul Albertus (Ph.D., 2009), and Maureen H. Tang (Ph.D., 2012). | https://en.wikipedia.org/wiki/John_Newman_(scientist) |
John Peter Novembre (born 1977 or 1978) is a computational biologist at the University of Chicago . He received a MacArthur Fellowship in 2015. Novembre has developed data visualization and analysis techniques to investigate correlations between genomic diversity, geography, and demographic structure. [ 1 ]
Novembre completed his undergraduate education in biochemistry at Colorado College in 2000. [ 2 ] He then received a PhD in population genetics in 2006 at UC Berkeley ; he was supervised by Montgomery Slatkin . [ 3 ] He then went on to do postdoctoral research with Matthew Stephens in Chicago. [ 3 ] In 2008, Novembre joined the Department of Ecology and Evolutionary Biology at the University of California, Los Angeles . [ 4 ]
This article about a biologist from the United States is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/John_Novembre |
John P. Ferraris (born April 1947) is an American chemist and professor at the University of Texas at Dallas . He is known for his pioneering work in the field of organic electronics, particularly the discovery that a charge-transfer complex between tetrathiafulvalene (TTF) and tetracyanoquinodimethane (TCNQ) exhibits high electrical conductivity. [ 1 ] This finding helped establish the foundation for the development of conducting polymers and organic electronic materials.
Ferraris earned his B.A. in chemistry from Saint Michael's College in Vermont in 1969. [ 2 ] He then completed both an M.A. (1971) and a Ph.D. (1974) in organic chemistry at Johns Hopkins University . [ 2 ] While a graduate student, he co-authored a seminal paper demonstrating high conductivity in a 1:1 charge-transfer salt of TTF and TCNQ, marking a significant advance in the field of organic conductors. [ 1 ]
Following his doctoral studies, Ferraris was a National Research Council postdoctoral fellow at the National Bureau of Standards (now NIST) from 1973 to 1975. [ 3 ]
Ferraris joined the chemistry faculty at the University of Texas at Dallas in 1975. [ 2 ] He became a full professor in 1992 and served as Head of the Department of Chemistry and Biochemistry from 1995 to 2017. [ 3 ] Between 2003 and 2006, he was Interim Dean of the School of Natural Sciences and Mathematics. From 2006 to 2009, he held the Cecil H. and Ida Green Chair in Systems Biology Science. [ 2 ]
He has authored over 150 publications and holds numerous U.S. patents. [ 2 ] Ferraris has collaborated on interdisciplinary research in electroactive polymers, nanomaterials, gas separation membranes, and artificial muscles. He played a key role in the UT Dallas NanoTech Institute , working alongside Alan MacDiarmid, Ray Baughman, and Anvar Zakhidov. [ 4 ]
Ferraris co-authored the 1973 paper reporting high conductivity in the TTF-TCNQ charge-transfer complex. [ 1 ] This was the first demonstration of metallic-like conductivity in an organic material and laid the foundation for the field of organic metals and conducting polymers.
He developed low bandgap conjugated polymers for use in optoelectronic devices and contributed to the design of conductive membranes and polymer-based supercapacitors. [ 5 ]
Ferraris co-developed super-tough carbon nanotube fibers [ 6 ] and co-invented chemically powered artificial muscles. [ 4 ] | https://en.wikipedia.org/wiki/John_P._Ferraris |
John Charles Polanyi PC CC FRSC OOnt FRS ( Hungarian : Polányi János Károly ; born 23 January 1929) is a German-born Canadian chemist . He was awarded the 1986 Nobel Prize in Chemistry for his research in chemical kinetics .
Polanyi was born into the prominent Hungarian Polányi (Pollacsek) family in Berlin , Germany, prior to emigrating in 1933 to the United Kingdom where he was subsequently educated at the University of Manchester , and did postdoctoral research at the National Research Council in Canada and Princeton University in New Jersey . Polanyi's first academic appointment was at the University of Toronto , and he remains there as of 2019 [update] .
In addition to the Nobel Prize, Polanyi has received numerous other awards, including 33 honorary degrees, the Wolf Prize in Chemistry and the Gerhard Herzberg Canada Gold Medal for Science and Engineering . Outside his scientific pursuits, Polanyi is active in public policy discussion, especially concerning science and nuclear weapons. His father, Mihály ( Michael ), was a noted chemist and philosopher. His uncle, Károly ( Karl ) was a renowned political economist, best known for his seminal work, The Great Transformation . [ 2 ] According to György Marx , he was one of " The Martians ", a group of prominent Hungarian scientists who emigrated to the United States in the first half of the 20th century. [ 3 ]
Polanyi's father Michael was born Jewish and converted to Catholicism. Polanyi's family moved from Germany to Britain in 1933, partly as a result of the persecution of Jews under Adolf Hitler . [ 4 ] During World War II , Polanyi's father sent him to Canada for three years when he was 11, so he would be safe from German bombings . [ 5 ] While living in Toronto, he attended the University of Toronto Schools . After returning to Britain, Polanyi finished high school and attended university at Manchester , where he received his undergraduate degree in 1949 and his PhD in 1952. [ 6 ] Although his university education was focused in science, he was not convinced it was his calling after finishing high school, when he briefly considered a career as a poet. [ 7 ] His father, Michael Polanyi , was a professor in the chemistry department during his first year of university, before transferring to a newly created position in the social studies department. Polanyi's supervisor during his graduate studies was Ernest Warhurst , a former student of his father's. [ 8 ] After completing his PhD studies, Polanyi did postdoctoral research at the National Research Council in Ottawa, Ontario from 1952 until 1954, where he worked with Edgar William Richard Steacie . [ 8 ] From 1954 until 1956, he was a research associate at Princeton University . [ 6 ]
John Polanyi started at the University of Toronto as a lecturer in 1956. He moved up the ranks quickly at the university, being promoted to assistant professor in 1957, associate professor in 1960 and becoming a full professor in 1962. In 1975, he was named University Professor, an honorary title he has retained since. [ 6 ]
Polanyi's PhD studies at Manchester University focused on measuring the strengths of chemical bonds using thermal dissociation, building on Warhurst's graduate studies using a sodium flame apparatus to determine the likelihood that a collision between a sodium atom and another molecule would lead to a chemical reaction . [ 8 ] For the majority of his career, Polanyi's research has focused on chemical dynamics, attempting to determine the mechanics of a chemical reaction , and the properties of chemical species in the transition state . [ 5 ] While at the National Research Council (NRC), Polanyi evaluated transition state theory for its predictive powers, coming to the conclusion that the theory was flawed, largely due to a lack of knowledge about the forces at play in the transition state. [ 8 ] Near the end of his stay at NRC, Polanyi worked in Gerhard Herzberg 's lab, using spectroscopy to examine vibrational and rotational excitation in iodine molecules. [ 8 ] During Polanyi's time at Princeton University , he worked with Sir Hugh Taylor and his colleagues, Michael Boudart and David Garvin. He was influenced by studies conducted at Princeton looking at the vibrationally excited reaction products between atomic hydrogen and ozone . [ 8 ]
When Polanyi moved to the University of Toronto , his first graduate students were looking for enhanced reaction rates with vibrationally excited hydrogen, as well as looking for the presence of vibrationally excited hydrogen chloride during the exothermic reaction of molecular chlorine with atomic hydrogen. [ 8 ] Graduate student Kenneth Cashion was working with Polanyi when they made their first discoveries about chemiluminescence , the light emitted by an atom molecule when it is in an excited state . This work was first published in 1958. [ 9 ]
In 2009, Polanyi and his colleagues published a paper in Nature Chemistry , entitled "Molecular dynamics in surface reactions." [ 10 ] This more recent research could be influential in nanotechnology , building devices from single atoms and molecules. [ 11 ] Polanyi's work still focuses on the basic workings of chemical reactions, but since his Nobel Prize win in 1986, his methods have changed. While in Sweden for the award ceremony, he encountered the three scientists who were awarded the 1986 Nobel Prize in Physics , who were honoured for their work in electron optics and scanning tunneling microscopy . [ 12 ] This technology allowed Polanyi and his colleagues to monitor chemical reactions on a very small scale, rather than observing the energy being released using infrared technology. His lab at the University of Toronto currently has 4 scanning tunneling microscopes, valued at approximately $750,000 each. [ 11 ]
In addition to his scientific pursuits, Polanyi has also always been keenly aware of the world at large. As a student, he edited a newspaper and displayed an interest in politics. [ 8 ] Although his father was a scientist, he did not demonstrate an immediate affinity for chemistry. [ 5 ] Beginning in the 1950s, Polanyi became involved in public affairs, especially concerning nuclear weapons . [ 8 ] He founded Canada's Pugwash group in 1960, and served as the chairman for the group from its inception until 1978. [ 8 ] Pugwash is a global movement that received the Nobel Peace Prize in 1995. Their goal is to reduce armed conflict and seek solutions to global problems. [ 13 ] He has also been a supporter of "pure" science, and a critic of government policies that do not support such research. [ 9 ] He is also a supporter of the Campaign for the Establishment of a United Nations Parliamentary Assembly , an organisation which campaigns for democratic reformation of the United Nations, and the creation of a more accountable international political system. [ 14 ] Polanyi often accepts speaking engagements to discuss issues relating to social justice, peace and nuclear proliferation, despite his busy research schedule. [ 11 ] He frequently comments on science and public policy issues via the Letters to the Editor and Opinion sections of The Globe and Mail newspaper. [ 15 ] [ 16 ] [ 17 ] He currently serves on the National Advisory Board of the Center for Arms Control and Non-Proliferation, the research arm of Council for a Livable World . [ 18 ]
Polanyi was awarded the 1986 Nobel Prize in Chemistry for his work in chemical kinetics . He shared the prize with Dudley Herschbach of Harvard University and Yuan T. Lee of the University of California . The trio were honoured for "their contributions concerning the dynamics of chemical elementary processes." [ 19 ] Polanyi's contributions were centred around the work he did developing the technique of infrared chemiluminescence . This technique was used to measure weak infrared emissions from a newly formed molecule in order to examine energy disposal during a chemical reaction. [ 19 ] Polanyi's Nobel lecture upon receipt of the award was entitled "Some Concepts in Reaction Dynamics." [ 20 ]
Polanyi had mixed feelings about the impact of the Nobel Prize on his research, feeling that his name on research proposals and papers often brought additional scrutiny, and also had people questioning his dedication to science after the honour. Polanyi said, "There is a very reasonable suspicion that you are so busy doing the things that Nobel Prize winners do that you are actually only giving half your mind to science." [ 11 ]
His Nobel victory also signaled a change in his research direction. The 1986 Nobel Prize in Physics was awarded to Ernst Ruska , Gerd Binnig and Heinrich Rohrer for their work in electron microscopes and scanning tunnelling microscopy (STM). [ 12 ] This research piqued Polanyi's interest while he was in Sweden for the ceremony. After returning to Toronto, Polanyi and his colleagues looked into the technique and now have four STMs, which they use to picture chemical reactions at the molecular level, rather than using infrared detection and chemiluminescence. [ 11 ]
Polanyi's Nobel medal is on display at Massey College (University of Toronto) where he is also a Senior Fellow.
He was elected a Fellow of the Royal Society (FRS) in 1971 . [ 1 ] In 1974, Polanyi was made an Officer of the Order of Canada . [ 21 ] In 1979, he was promoted to Companion. [ 6 ] He has received many other awards throughout his career, including the Marlow Medal of the Faraday Society in 1962, Centenary Medal of the British Chemical Society in 1965, the Steacie Prize for Natural Sciences in 1965 (shared), the Noranda Award of the Chemical Institute of Canada in 1967, the Henry Marshall Tory Medal of the Royal Society of Canada in 1977, the Wolf Prize in Chemistry in 1982 (shared), the Izaak Walton Killam Memorial Prize in 1988, the Royal Medal of the Royal Society in 1989, and the John C. Polanyi Lecture Award of the Canadian Society for Chemistry in 1992. [ 6 ] In 2007, Polanyi was awarded the Gerhard Herzberg Canada Gold Medal for Science and Engineering . [ 22 ] The Royal Society of Chemistry honoured Polanyi as their 2010 Faraday Lectureship Prize . [ 23 ]
Polanyi has received many honorary degrees from 25 institutions, including Waterloo in 1970, Harvard University in 1982, Ottawa in 1987, and Queen's in 1992. [ 6 ] He is a fellow of the Royal Society of Canada , the Royal Society of London , the Royal Society of Edinburgh , and a member of the American Academy of Arts and Sciences , the U.S. National Academy of Sciences , the Pontifical Academy of Sciences , and an Honorary Fellow of the Royal Society of Chemistry of the United Kingdom and the Chemical Institute of Canada . [ 6 ]
Polanyi was pictured on a Canada Post first class postage stamp on 3 October 2011, issued to salute the International Year of Chemistry . In 1992, Polanyi was appointed to the Queen's Privy Council of Canada. [ 24 ]
Polanyi was awarded the 2022 Andrei Sakharov Prize. The award cites Polanyi's seven decades of activism for a nuclear-weapons-free world, for upholding human rights and freedom of speech globally, for public education on the essential role of science in society, and for a visionary approach to bringing about a hopeful, peaceful future. [ 25 ]
In honour of Polanyi's Nobel Prize win, the Ontario government established the "John Charles Polanyi Prizes". These prizes are each worth $20,000, and are awarded to young researchers in the province in a postdoctoral fellowship or who have recently started a faculty appointment at an Ontario university. The prizes are awarded in similar categories to the Nobel Prizes, broadly defined as: Physics , Chemistry , Physiology or Medicine, Economics and Literature. [ 26 ]
Canada's Natural Sciences and Engineering Research Council (NSERC) created the John C. Polanyi award to recognize a researcher or researchers whose work in an NSERC-supported field has led to an outstanding advance in the field. The research must have been conducted in Canada, and have been at least partially supported by NSERC funding. The award consists partially of a $250,000 grant for the winner. [ 27 ] The inaugural winner of the John C. Polanyi Award was the Sudbury Neutrino Observatory . [ 28 ] In 2011, the award was presented to Victoria M. Kaspi , an astrophysicist at McGill University . [ 29 ]
Polanyi started publishing his scientific research in 1953. As of 2010, he has published over 250 scientific papers. [ 30 ] His writing is not limited to his scientific interests, as he has published over 100 articles on policy, the impact of science on society and armament control. [ 6 ] In 1970, he produced a film entitled Concepts in Reaction Dynamics , and he co-edited a book called The Dangers of Nuclear War . [ 6 ]
In 2010, the Toronto District School Board voted to change the name of Sir Sandford Fleming Academy to the John Polanyi Collegiate Institute to coincide with a move to a new location. The new school opened in September 2011. [ 13 ]
Polanyi was born in 1929 to Michael and Magda Elizabeth Kemény Polanyi in Berlin , Germany. [ 6 ] His father was born in 1891, in Hungary . [ 4 ] His uncle, Karl was an economist, noted for his criticism of market capitalism . [ 9 ] His brother George was noted for his defence of market capitalism. His paternal grandfather, Mihaly Pollacsek, built railways. [ 9 ] Mihaly Pollacsek Magyarised the family's name to Polanyi, but did not change his own name. [ 4 ] The Polanyi's were non-observant Jews , although Michael Polanyi became a Christian .
In 1958, Polanyi married Anne Ferrar Davidson (1929–2013). [ 31 ] He has two children – a daughter, Margaret, born in 1961 and a son, Michael, born in 1963. [ 6 ] His daughter is a journalist, and his son is a political scientist who started his career as a physicist. [ 8 ] Polanyi is currently married to portrait artist Brenda Bury . [ 32 ] Outside his scientific and policy endeavours, Polanyi's interests include art, literature and poetry. He was an avid white water canoeist in his younger days, but has replaced that with walking and skiing. [ 8 ] | https://en.wikipedia.org/wiki/John_Polanyi |
Sir John Anthony Pople KBE FRS [ 1 ] (31 October 1925 – 15 March 2004) [ 1 ] [ 6 ] was a British theoretical chemist who was awarded the Nobel Prize in Chemistry with Walter Kohn in 1998 for his development of computational methods in quantum chemistry . [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ]
Pople was born in Burnham-on-Sea , Somerset, and attended the Bristol Grammar School . He won a scholarship to Trinity College, Cambridge , in 1943. He received his Bachelor of Arts degree in 1946. Between 1945 and 1947 he worked at the Bristol Aeroplane Company . He then returned to the University of Cambridge and was awarded his PhD in mathematics in 1951 on lone pair electrons . [ 2 ]
After obtaining his PhD, he was a research fellow at Trinity College, Cambridge and then from 1954 a lecturer in the mathematics faculty at Cambridge . In 1958, he moved to the National Physical Laboratory , near London as head of the new basics physics division. He moved to the United States of America in 1964, where he lived the rest of his life, though he retained British citizenship. Pople considered himself more of a mathematician than a chemist, but theoretical chemists consider him one of the most important of their number. [ 12 ] In 1964 he moved to Carnegie Mellon University in Pittsburgh, Pennsylvania , where he had experienced a sabbatical in 1961 to 1962. In 1993 he moved to Northwestern University in Evanston, Illinois , where he was Trustees Professor of Chemistry until his death. [ 13 ]
Pople's major scientific contributions were in four different areas: [ 14 ]
Pople's early paper on the statistical mechanics of water, according to Michael J. Frisch , "remained the standard for many years". [ 14 ] [ 15 ] This was his thesis topic for his PhD at Cambridge supervised by John Lennard-Jones . [ 2 ] [ 12 ]
In the early days of nuclear magnetic resonance he studied the underlying theory, and in 1959 he co-authored the textbook High Resolution Nuclear Magnetic Resonance with W.G. Schneider and H.J. Bernstein. [ 14 ]
He made major contributions to the theory of approximate molecular orbital (MO) calculations, starting with one identical to the one developed by Rudolph Pariser and Robert G. Parr on pi electron systems, and now called the Pariser–Parr–Pople method . [ 16 ] Subsequently, he developed the methods of Complete Neglect of Differential Overlap ( CNDO ) (in 1965) and Intermediate Neglect of Differential Overlap ( INDO ) for approximate MO calculations on three-dimensional molecules, and other developments in computational chemistry . In 1970 he and David Beveridge coauthored the book Approximate Molecular Orbital Theory describing these methods.
Pople pioneered the development of more sophisticated computational methods, called ab initio quantum chemistry methods , that use basis sets of either Slater type orbitals or Gaussian orbitals to model the wave function. While in the early days these calculations were extremely expensive to perform, the advent of high speed microprocessors has made them much more feasible today. He was instrumental in the development of one of the most widely used computational chemistry packages, the Gaussian suite of programs, including coauthorship of the first version, Gaussian 70. [ 17 ] One of his most important original contributions is the concept of a model chemistry whereby a method is rigorously evaluated across a range of molecules. [ 14 ] [ 18 ] His research group developed the quantum chemistry composite methods such as Gaussian-1 (G1) and Gaussian-2 (G2). In 1991, Pople stopped working on Gaussian and several years later he developed (with others) the Q-Chem computational chemistry program. [ 19 ] Prof. Pople's departure from Gaussian, along with the subsequent banning of many prominent scientists, including himself, from using the software gave rise to considerable controversy among the quantum chemistry community. [ 20 ]
The Gaussian molecular orbital methods were described in the 1986 book Ab initio molecular orbital theory by Warren Hehre, Leo Radom, Paul v.R. Schleyer and Pople. [ 21 ]
Pople received the Wolf Prize in Chemistry in 1992, and the Nobel Prize in Chemistry in 1998. [ 22 ] He was elected a Fellow of the Royal Society (FRS) in 1961 . [ 1 ] He was made a Knight Commander (KBE) of the Order of the British Empire in 2003. He was a founding member of the International Academy of Quantum Molecular Science .
An IT room and a scholarship are named after him at Bristol Grammar School , as is a supercomputer at the Pittsburgh Supercomputing Center .
Pople married Joy Bowers in 1952 and was married until her death from cancer in 2002. Pople died of liver cancer in Chicago in 2004. He was survived by his daughter Hilary, and sons Adrian, Mark and Andrew. [ 23 ] In accordance with his wishes, Pople's Nobel Medal was given to Carnegie Mellon University by his family on 5 October 2009. | https://en.wikipedia.org/wiki/John_Pople |
John Robert Huizenga (April 21, 1921 – January 25, 2014) was an American physicist who helped build the first atomic bomb and who also debunked University of Utah scientists' claim of achieving cold fusion . [ 1 ] [ 2 ] [ 3 ]
John Robert Huizenga was born on a farm near Fulton, Illinois , the son of Henry and Josie (Brands) Huizenga. [ 4 ] He attended Erie High School and Morrison High School , graduating from the latter in 1940. He continued his education at Calvin College in Michigan, from which he received a bachelor's degree in 1944. He would maintain his ties to Calvin later in life, for example collaborating on fundamental nuclear research with his Calvin friend Roger Griffioen , [ 5 ] who had gone on to become a professor there. Calvin would name him one of the college's Distinguished Alumni in 1975. [ 6 ]
Along with other Calvin students, he was recruited after graduation to work for the Manhattan Project , at the Project's site in Oak Ridge, Tennessee , that was dedicated to the production of highly enriched uranium . Following his time in Oak Ridge, he continued his education at the University of Illinois , receiving a Doctor of Philosophy degree in physical chemistry in 1949. On completing his studies he held joint appointments at the University of Chicago and Argonne National Laboratory . [ 2 ]
During World War II, Huizenga supervised teams at the Manhattan Project in Oak Ridge, Tenn., involved in enriching uranium used in the atomic weapon dropped on Hiroshima in August 1945. During his Argonne years, as a result of examining debris from the " Ivy Mike " nuclear test in 1952, Huizenga was part of the team that added two new synthetic chemical elements , einsteinium and fermium , to the periodic table . [ 1 ] [ 2 ] [ 7 ] [ 8 ] Huizenga and his colleagues were at first unable to publish papers on their discoveries in the open literature, because of classification concerns relating to the nuclear test, [ 9 ] but these concerns were eventually resolved and the team was able to publish in Physical Review and thus claim priority for their discovery. During his Argonne years he was one of the founders of the Gordon Research Conferences on nuclear chemistry , serving as chairman of the nuclear chemistry Gordon Conference in 1958. [ 10 ] He received a Guggenheim Fellowship in 1964 and took a sabbatical from Argonne to further his studies as a visiting professor at the University of Paris for the 1964–1965 academic year.
In 1967, he became a professor of chemistry and physics at the University of Rochester where he worked for the remainder of his career, apart from a second Guggenheim Fellowship that allowed him to engage in research during the 1973–1974 school year at the University of California, Berkeley , the Technische Universität München , and the Niels Bohr Institute in Copenhagen . His research interests at Rochester covered topics in nuclear structure of actinides , nuclear fission , and nuclear reactions between heavy ions. He was chairman of the Department of Chemistry from 1983 to 1988, [ 11 ] retiring as Tracy H. Harris Professor (later Professor Emeritus) of Chemistry.
During Huizenga's time at Rochester, the university had its own particle accelerator , a tandem Van de Graaff accelerator that produced beams of nuclei accelerated to energies of several MeV per nucleon. This facility, which opened in 1966, [ 12 ] afforded him the opportunity to continue his research program in experimental nuclear science. However, the limited beam energies available led him to more powerful accelerators, such as the SuperHILAC at Berkeley and the Los Alamos Meson Physics Facility , LAMPF, at Los Alamos National Laboratory , for his experimental work. His LAMPF proposal to study actinide muonic atoms was one of the earliest experiments to receive beam time at the LAMPF stopped-muon facility. [ 13 ]
In 1989, Huizenga co-chaired, with Norman Ramsey , a panel convened by the United States Department of Energy which attempted to debunk claims by two University of Utah chemists that they had achieved nuclear fusion at room temperature . The findings of the Huizenga/Ramsey panel, although highly skeptical of the reality of cold fusion, were cautious:
Based on the examination of published reports, reprints, numerous communications to the Panel and several site visits, the Panel concludes that the experimental results of excess heat from calorimetric cells reported to date do not present convincing evidence that useful sources of energy will result from the phenomena attributed to cold fusion. ... The Panel concludes that the experiments reported to date do not present convincing evidence to associate the reported anomalous heat with a nuclear process. ...
Current understanding of the very extensive literature of experimental and theoretical results for hydrogen in solids gives no support for the occurrence of cold fusion in solids. Specifically, no theoretical or experimental evidence suggests the existence of D-D distances shorter than that in the molecule D2 or the achievement of "confinement" pressure above relatively modest levels. The known behavior of deuterium in solids does not give any support for the supposition that the fusion probability is enhanced by the presence of the palladium, titanium, or other elements.
Nuclear fusion at room temperature, of the type discussed in this report, would be contrary to all understanding gained of nuclear reactions in the last half century; it would require the invention of an entirely new nuclear process. [ 14 ]
However, Huizenga later published a book titled "Cold Fusion: The Scientific Fiasco of the Century". [ 1 ] [ 2 ]
Huizenga was elected to the National Academy of Sciences in 1976 and the American Academy of Arts and Sciences (Fellow) in 1992. He was a 1966 recipient of the Ernest Orlando Lawrence Award bestowed by the United States Atomic Energy Commission .
Huizenga married Dorothy Koeze in 1946. [ 4 ] They had two sons and two daughters. One son, Dr. Robert Huizenga , is a prominent physician whose career has included a stint as team physician for the Los Angeles Raiders American football team.
Following his retirement from Rochester, Huizenga and his wife moved to North Carolina , where he continued to serve on advisory committees at major accelerator laboratories, worked to debunk cold fusion, and wrote his memoirs. Dolly Huizenga died in 1999. John Huizenga died of heart failure in San Diego, California , in January 2014, aged 92. [ citation needed ] | https://en.wikipedia.org/wiki/John_R._Huizenga |
The John R. Ragazzini Education Award is an annual accolade bestowed by the American Automatic Control Council (AACC) since 1979, [ 1 ] [ 2 ] [ 3 ] named in honor of John R. Ragazzini , a pioneering American electrical engineer and educator. [ 4 ] [ 5 ] [ 6 ] [ 7 ] This prestigious award recognizes outstanding contributions to education in the field of automatic control .
The award celebrates those who have made significant advancements in control education in the United States, either through teaching, textbook authorship, mentoring, or other forms of educational activity that promote the discipline of automatic control. It is one of the highest honors in the field of control education and underscores the commitment to academic excellence and innovation in engineering education. | https://en.wikipedia.org/wiki/John_R._Ragazzini_Award |
John Read Cronin (August 3, 1936 – June 30, 2010) was an American biochemist and organic geochemist renowned for his pioneering research in the field of meteoritic organic chemistry . His work significantly advanced the understanding of the role of extraterrestrial organic molecules in the origin of life .
John Read Cronin was born on August 3, 1936, in Marietta, Ohio. He grew up in New Philadelphia, Ohio, where he developed an early interest in science and nature. Cronin's fascination with chemistry and the natural world led him to pursue a career in biochemistry . [ citation needed ]
Cronin attended The College of Wooster , where he obtained his undergraduate degree in chemistry. He then went on to earn a Ph.D. in biochemistry from the University of Colorado School of Medicine in Denver. His doctoral research laid the foundation for his later work in organic chemistry and prebiotic chemistry . [ citation needed ]
In 1966, Cronin joined the faculty at Arizona State University (ASU) as a professor of biochemistry. At ASU, he became involved in the emerging field of exobiology , focusing on the study of organic materials in extraterrestrial environments. His work at the ASU Center for Meteorite Studies , particularly with carbonaceous chondrite meteorites, positioned him as a leading figure in the field. [ citation needed ]
Cronin's research explored the organic chemistry of meteorites, with a specific focus on carbonaceous chondrites like the Murchison meteorite . His work provided valuable insights into the diversity and complexity of extraterrestrial organic compounds and their potential role in the origin of life on Earth. John worked closely with Sandra Pizzarello with whom he made a number of important discoveries and collaborated extensively.
The meteorite center explained the significance of Cronin's findings and contributions. [ 1 ] As the world consensus at the time was skeptical about the presence of amino acids in meteorites , John Cronin and his colleagues conducted independent tests using different analytical techniques to detect amino acids in various meteorites, including Murchison, Murray, and Allende. Their findings showed that:
This led Cronin and his team to further study the organics present in meteorites. They identified various compounds, including carboxylic acids , complex amino acids, and aliphatic hydrocarbons also using nuclear magnetic resonance .
The team also collaborated with Samuel Epstein from Caltech to examine the isotopic signatures of organic molecules in meteorites, which further supported their extraterrestrial origin. Cronin and Sandra Pizzarello discovered the asymmetry of organic molecules before they fell to Earth, which might have originated from the interstellar medium. This research is significant because the exclusively left-handed nature of life's molecules is essential for the structures and functions of terrestrial biopolymers and is assumed to be crucial for the emergence of life.
Cronin's extensive analysis of carbonaceous chondrite meteorites revealed a rich diversity of organic molecules, including amino acids, hydrocarbons, and nucleobases. His research demonstrated that these meteorites contain complex organic compounds that could have been significant in prebiotic chemistry. [ citation needed ]
Key publication:
Cronin's research on the chirality of meteoritic amino acids provided evidence of non-racemic mixtures, suggesting a potential extraterrestrial source of chiral asymmetry. This finding has implications for the development of homochirality in biological molecules on Earth.
Key publication:
Cronin conducted isotopic analyses of meteoritic organic compounds, revealing distinct isotopic compositions that supported their non-terrestrial origin. This work provided crucial insights into the extraterrestrial sources of prebiotic molecules. They investigated and published significant work on the Murchison meteorite [ 2 ]
Key publication:
Cronin's research explored how meteorite impacts could synthesize organic compounds from simpler precursors, highlighting the potential role of impact-generated environments in prebiotic chemistry.
Key publication: | https://en.wikipedia.org/wiki/John_Read_Cronin |
John S. Rodwell (1946 – present) is an ecologist who was based at the University of Lancaster , noted for his role in the development of the British National Vegetation Classification and as editor of the five volumes of British Plant Communities . [ 1 ]
Rodwell graduated in Botany from the University of Leeds in 1968, then researched limestone vegetation at the University of Southampton under Joyce Lambert for his PhD in Biology , awarded in 1974. He also trained for the priesthood at Ripon College Cuddesdon , University of Oxford , maintaining this vocation as a non-stipendiary priest since 1974 in the Diocese of Blackburn since 1975 and is honorary canon of Blackburn Cathedral . [ 2 ] [ 3 ] [ 4 ] [ 5 ]
In the same year, 1975, he became co-ordinator of research leading to the development of the British National Vegetation Classification (NVC). at Lancaster University , becoming editor of the NVC, a task that dominated his working life for more than two decades. [ 2 ] All five volumes of British Plant Communities , which describe the NVC, were edited by Rodwell. [ 6 ]
He joined the faculty of Lancaster University in 1991, was made Professor of Ecology in 1997 and retired in 2004 but has continued to teach and publish since then. In 2009 he was awarded the Institute of Ecology and Environmental Management medal of honour. [ 2 ]
He is a Honorary Member of the International Association for Vegetation Science (2010). [ 7 ] | https://en.wikipedia.org/wiki/John_S._Rodwell |
John H. Safer (September 6, 1922 – December 7, 2018) was an American sculptor. Safer's varied career spanned work in theater lighting , television, real estate , politics and banking.
Safer was best known for his monumental sculptures, but he has also created many smaller works. These include award sculptures for organizations such as the National Air and Space Museum , the PGA Tour , the Georgetown University Lombardi Cancer Center , the World Peace Foundation, and the Shakespeare Guild.
Safer's works stand in museums, galleries and embassies throughout the world. In 1972 and in 1989 the U.S. Department of State sent a group of Safer sculptures abroad to be exhibited as examples of America's finest art. He died in December 2018 at the age of 96. [ 1 ] [ 2 ]
Safer's earliest sculptures in the 1950s and 1960s were small works of Lucite . Over time he also began to work in bronze and stainless steel . The pieces became larger and in 1979 his first public commission, Judgment , a multi-ton patinated bronze , was installed at Harvard Law School in Cambridge, Massachusetts . [ 3 ] [ 4 ]
This was the first in a long string of public installations.
As the commissions grew in number they grew in size as well. Interplay , created in 1987, is 18 feet (5.5 m) high. Leading Edge , created in 1989, is 20 feet (6.1 m) high. His hallmark work, Ascent , which stands at the entrance of the Smithsonian Institution's Udvar-Hazy Center at Dulles Airport in Virginia , is 75 feet (23 m) high.
"Through his work, John has tried to capture the essence and reduce the subject to the pure line in space that Aristotle believed to be the basis of sculpture." [ 5 ]
John Safer was born and raised in Washington, D.C. , the only child of John and Rebecca Herzmark Safer. His father, who operated a moving and storage business, was a lawyer who graduated from Georgetown University Law School at the head of his class. His mother Rebecca Herzmark Safer was a social activist , suffragette and intellectual. John learned to read and write by the age of four. At this time his mother entered him into first grade at the Maret French School.
Safer continued as a precocious student. Fluent in French , he entered high school at the age of eleven and graduated when he was fourteen. He was pressured by his mother to enroll at Harvard University . Safer, uncomfortable at the thought of being a fourteen-year-old college student, deliberately failed the Harvard entrance exam by handing in blank pages. [ 6 ]
Safer instead attended Woodward Prep School. There he discovered his love for and ability in athletics . This theme would greatly influence his art and his life. Until then, his age and size had prevented him from participating in sports and left him with the sense that he was a misfit.
At the age of sixteen, Safer entered George Washington University where he majored in economics . He became an assistant to Professor Edward Acheson –– brother of the United States Secretary of State Dean Acheson –– who became a mentor. At the beginning of World War II , Safer enlisted in the United States Air Force to become a flying cadet .
Safer became a first lieutenant and served in India , Burma and China . When the war ended in 1945 he opted for an additional year in the Air Force hoping to fulfill a dream of seeing Europe 's great works of art while he was stationed there. His new assignment allowed him to visit the Parthenon , the Tate , and the Louvre . While in Rome , he learned that he was suddenly to be transferred to Athens . Unwilling to leave Italy without visiting the Accademia in Florence , Safer "borrowed" a jeep to make the drive to see Michelangelo 's David . The Accademia was closed but he convinced the caretaker to let him in. The two hours Safer spent alone with the masterpiece resulted in a seminal experience, but it was Michelangelo's other sculptures in the Gallery, The Prisoners , which gave Safer an insight that was to impact his entire life and transform his artistic career.
The Prisoners are heroic figures rising from rough hewn stone. The upper portion of the figures are finished while the lower part remains uncarved. As Safer studied The Prisoners he realized the power of the abstract –– a realization that gave direction to his future work.
After Safer graduated from Harvard Law School in 1949 his fascination with the emerging technology and promise of television prompted him to take a job as a handyman at WXEL in Cleveland, Ohio . He quickly rose to the position of program director . During this time his innovations led the new independent station to "beat the ratings of all the network affiliates." [ 7 ]
In 1953 Safer's father became terminally ill and he returned to Washington, D.C. to take over his father's affairs. Although Safer successfully parlayed these into a major real estate development business he did not find his commercial life a rewarding one.
In 1974 Safer entered the world of banking, becoming chairman of the executive committee of Financial General Bankshares, and in 1981 the chairman of the Board of DC National Bank which later became part of Bank of America .
In 1999 Safer became chairman of the Board of Materia, Inc. Materia specializes in Olefin metathesis , and is noted for its Nobel Prize–winning Green chemistry .
Safer never formally studied art. His first forays into sculpture were experiments with plastic swizzle sticks. In 1957 he made his first creations, and he continued to experiment, eventually beginning to carve Lucite . In 1969 Safer had his first show in Pittsburgh, Pennsylvania at the Michael Berger Gallery. Several shows in private galleries followed with a major exhibition at the Pyramid Gallery in Washington, D.C. [ 8 ]
In 1971 the renowned art collector and U.S. Ambassador to Great Britain , Walter Annenberg , invited Safer to have an exhibition at the American Embassy in London .
In 1972 President Gerald Ford presented Safer's Limits of Infinity to King Juan Carlos of Spain as a gift of state. This in turn led to several major events in Safer's sculptural career. As a result of a news report of President Ford's gift, the Dean of Harvard Law School sought to acquire a Safer sculpture for the school. This culminated in 1979 with the installation of Judgment , a monumental bronze work which was presented to Harvard Law School as a gift of Safer's class of 1949. This was Safer's first monumental public work.
John McArthur , the Dean of Harvard Business School visited the palace at Zarzuela where King Juan Carlos had installed Limits of Infinity . Moved by the sculpture, Dean McArthur returned to America and commissioned Safer's 20-foot-high (6.1 m) Search for Harvard Business School. The patinated bronze was installed on the Business School grounds in 1984 adjacent to the spot where Safer's daughter, Janine, received her MBA five days later.
In 1985 Safer was invited to exhibit sculpture in the Pioneers of Flight Hall at the Smithsonian Institution's National Air and Space Museum , in Washington, D.C. He has the distinction of being the only artist to have ever had an exhibition in the central gallery of the most visited museum in the
world. [1]
In 1989 the U.S. Department of State again sent Safer sculptures to Europe. As of 2008, the department has exhibited Safer sculpture in London , Paris , Beijing , Dublin , Bern , Lisbon , Brussels , Bucharest , Belgrade , Nassau , Washington, and New Deli. Both public and private exhibitions of Safer sculpture can be seen in venues throughout the world.
Safer continues to create sculpture. He works with his stepdaughter Kathryn Scott, to whom he taught his trade and offered his mantle. [ 9 ] In 2007, they began work on a monumental sculpture, Quest, for the Johns Hopkins Wilmer Eye Institute . The 35-foot-high (11 m) stainless steel fabricated sculpture and state of the art research center, the Robert H. and Clarice Smith Building, [ 10 ] was dedicated two years later, on October 16, 2009, 80 years to the day after the pioneering institute's first building made its debut. Safer, a patient, donated the multi-ton sculpture as a gift of appreciation [ 11 ] It is one of the largest gifts of art that Johns Hopkins has received. In December 2011, Scott and Safer began work on a model for a monumental sculpture for the Marine Aviation Memorial.
Over the next ten years the Safer-Scott partners continued to collaborate on private and public projects. The eleven foot-high (3.4 m) mirror finished, Interplay , was commissioned for the LEED wing of the $340M Kimmel Cancer Center expansion at Sibley Memorial Hospital in Washington, DC. In 2014 Scott began negotiations with MGM Resorts International for a centerpiece at MGM National Harbor in Maryland. The 60 foot high (18.3 m) stainless steel sculpture, Unity , weighting eighteen thousand pounds and unprecedented in its scale, was installed two years later on November 12, 2016—one month before the opening of the $1.4B resort.
Safer explains the motivation behind his sculpture:
At its best, sculpture can give a glimpse of the relationship between that which lies within us and that which does not. I strive to make works that will elevate the human spirit. What I see and try to capture is the movement of beauty. I try to freeze a line of motion that expresses strength, power, or grace. I try to grasp and make permanent something that is ephemeral.
What I aspire to, as an artist, is contained in the philosophy of the Golden Age of Greece : Truth is beauty; nothing in excess; know thyself. The essential thought behind the creation of my Sculpture is humanity. My goal is to increase the awareness of the beauty of life for myself and for others.
I read once that Mozart could conceptualize a whole symphony in an instantaneous flash. Then he would have the laborious task of committing it to paper. This struck a chord , Mozartian I hope, in me. That's the way I create most of my sculpture. I get a kind of instantaneous flash, a look, a total concept, and then I have to give it substance, make it occupy space. [ 12 ]
Safer credits his wife, Joy, with giving him "a new perspective on the world ... which lifted my sculpture to a level I had not previously attained."
Safer's interest in sports has provided the inspiration behind many of his sculptures. Dancer and the Dance , Serve , Before the Wind , and Line of Flight are works that capture a line of athletic motion. [ 13 ]
As a youngster, Safer was ahead of, and therefore smaller than his classmates in school, so it was later that he discovered his own athletic prowess. [ 14 ] Safer has awards in marksmanship , baseball and bowling . Safer, now ninety, still plays competitive golf . In November 2012, Safer and his partner Jack Frazee won the Lyford Cay Shootout. Later that week, Safer and his team won the "B" flight in the Lyford Cay Four-Ball Invitational tournament, a tournament they won in 2007, when Safer was 85.
Safer has been awarded two honorary degrees: Doctor of Philosophy from Daniel Webster College and Doctor of Literature from Lees-McRae College . In May 2009, Safer received a third honorary degree– Doctor of Fine Arts from George Washington University . [ 15 ] Along with Rahm Emanuel and Jeanne L. Narum, Safer delivered a commencement speech, [ 16 ] from the National Mall , to the graduating class of 2009.
Safer explains the motivation behind his career:
There is one other basic principle that guides my work, my business career, and my life in general, and that is balance. I believe that the Aristotelian golden mean is as good a guiding philosophy for life as you can find. In business, I adhere to it continually, trying to balance the necessity for a successful business always to move forward with the caveat that too much motion can be counterproductive or unnecessarily dangerous. In art, the human spirit is gratified by balance, by a tonic note. And so I try to express a sense of balance and completeness in my work. [ 17 ]
Digitized Nov 13, 2007 ISBN 0-89674-008-0 , ISBN 978-0-89674-008-2
Contributor David Finn Published by Hudson Hills Press, 1992 Original from the University of Michigan
Digitized Nov 13, 2007 ISBN 1-55595-063-9 , ISBN 978-1-55595-063-7
Published by The Galleries, 1975 | https://en.wikipedia.org/wiki/John_Safer |
The John Stewart Bell Prize for Research on Fundamental Issues in Quantum Mechanics and their Applications (short form: Bell Prize ) was established in 2009, funded and managed by the University of Toronto , Centre for Quantum Information and Quantum Control (CQIQC). [ 1 ] Named after John Stewart Bell (the physicist behind Bell's theorem , a theorem whose experimental vindication led to a Nobel Prize), it is awarded every odd-numbered year, for significant contributions relating to the foundations of quantum mechanics and to the applications of these principles – this covers, but is not limited to, quantum information theory , quantum computation , quantum foundations, quantum cryptography and quantum control . [ 2 ] The selection committee has included Gilles Brassard , Peter Zoller , Alain Aspect , John Preskill , and Juan Ignacio Cirac Sasturain , in addition to previous winners Sandu Popescu , Michel Devoret and Nicolas Gisin . [ 3 ] | https://en.wikipedia.org/wiki/John_Stewart_Bell_Prize |
Koffler Scientific Reserve
John R. Stinchcombe (born 1974) is an American and Canadian ecological geneticist who is a professor of ecology and evolutionary biology at the University of Toronto . His research is on the ecology of natural selection, and the role of genetics in facilitating or constraining evolution, focusing almost exclusively on plants.
Stinchcombe grew up in Syracuse, NY, USA, in an outdoors-loving family. He was an undergraduate at Bucknell University , graduating in 1996. He then spent a summer working for the National Marine Fisheries Service, in Washington, D.C., before starting his Ph.D. at Duke University in 1996. He started in the Zoology Department, and finished his PhD in 2001 in the Biology Department, with a Certificate in Ecology. His PhD research was on the evolution of resistance and tolerance to herbivory in the Ivyleaf morning glory ( Ipomoea hederacea ). [ 1 ] Stinchcombe's post-doctoral work was at Brown University , working with Johanna Schmitt . His work there was on flowering time clines and genetics in mouse ear cress ( Arabidopsis thaliana ), [ 2 ] as well as growth plasticity in touch-me-nots ( Impatiens capensis ). [ 3 ]
Stinchcombe started a faculty position at the University of Toronto in 2005, in the Botany Department, and joined the Department of Ecology and Evolutionary Biology [ 4 ] at its creation.
Stinchcombe's research is on plant ecological genetics. Topics investigated by his lab include the genetics of flowering time, clines, phenotypic plasticity , plant-microbe interactions , natural selection in the field, evolution of gene expression , and the evolution of herbicide resistance . [ 5 ]
Stinchcombe served as the Secretary [ 6 ] for the Society for the Study of Evolution , and since 2013 he has been the Director of the Koffler Scientific Reserve , the University of Toronto's field research station. [ 7 ]
From Google Scholar Profile [ 8 ] | https://en.wikipedia.org/wiki/John_Stinchcombe |
John Stuart Anderson FRS , [ 1 ] FAA , (9 January 1908 – 25 December 1990) was a British and Australian scientist who was Professor of Chemistry at the University of Melbourne and Professor of Inorganic Chemistry at the University of Oxford . [ 2 ]
He was born in Islington , London , the son of a Scottish cabinet-maker, and attended school in the area but learned most of his chemistry at the Islington Public Library. His tertiary education was at the Northern Polytechnic Institute , Imperial College and the Royal College of Science , all in London. [ 2 ]
Anderson's most important research work was: [ 2 ]
In addition he carried out practical investigations on the composition of minerals mined in Australia, assisted on one project by Masters candidate Ken McTaggart who went on to be a senior research officer at CSIRO. He developed a love of the Australian bush and, with his family, a lifelong attachment to the country.
Anderson was co-author with Harry Julius Emeléus of the seminal textbook Modern Aspects of Inorganic Chemistry , first published in 1938, which went through numerous editions and translations for over thirty years. [ 4 ]
John Stuart Anderson died from cancer in Canberra on Christmas Day, 1990.
In memory of John, the University of Melbourne created the JS Anderson Prize awarded to a promising research student in the area of Chemistry.
Source [ 2 ]
Source [ 2 ] | https://en.wikipedia.org/wiki/John_Stuart_Anderson |
Sir John Edward Sulston CH FRS MAE (27 March 1942 – 6 March 2018 [ 11 ] [ 12 ] ) was a British biologist and academic who won the Nobel Prize in Physiology or Medicine for his work on the cell lineage and genome of the worm Caenorhabditis elegans in 2002 with his colleagues Sydney Brenner and Robert Horvitz at the MRC Laboratory of Molecular Biology . [ 13 ] He was a leader in human genome research and Chair of the Institute for Science, Ethics and Innovation at the University of Manchester . [ 14 ] [ 15 ] [ 16 ] Sulston was in favour of science in the public interest, such as free public access of scientific information and against the patenting of genes and the privatisation of genetic technologies. [ 17 ]
Sulston was born in Fulmer, Buckinghamshire , England [ 18 ] to Arthur Edward Aubrey Sulston and Josephine Muriel Frearson, née Blocksidge. [ 5 ] [ 19 ] His father was an Anglican priest and administrator of the Society for the Propagation of the Gospel . His mother quit her job as an English teacher at Watford Grammar School , to care for him and his sister Madeleine. [ 20 ] and home-tutored them until he was five. At age five he entered the local preparatory school, York House School, where he soon developed an aversion to games. He developed an early interest in science, having fun with dissecting animals and sectioning plants to observe their structure and function. [ 4 ] Sulston won a scholarship to Merchant Taylors' School, Northwood [ 5 ] and then to Pembroke College, Cambridge graduating in 1963 with a Bachelor of Arts [ 5 ] degree in Natural Sciences (Chemistry) . He joined the Department of Chemistry, University of Cambridge , after being interviewed by Alexander Todd [ 4 ] [ 21 ] and was awarded his PhD in 1966 for research in nucleotide chemistry. [ 3 ]
Between 1966 and 1969 he worked as a postdoctoral researcher at the Salk Institute for Biological Studies in La Jolla , California. [ 19 ] His academic advisor Colin Reese [ 3 ] [ 4 ] had arranged for him to work with Leslie Orgel , who would turn his scientific career onto a different pathway. Orgel introduced him to Francis Crick and Sydney Brenner , who worked in Cambridge. He became inclined to biological research. [ 20 ]
Although Orgel wanted Sulston to remain with him, Sydney Brenner persuaded Sulston to return to Cambridge [ when? ] to work on the neurobiology of Caenorhabditis elegans at the Medical Research Council (MRC) Laboratory of Molecular Biology (LMB). Sulston soon produced the complete map of the worm's neurons. [ 22 ] He continued work on its DNA and subsequently the whole genome sequencing. In 1998, the whole genome sequence was published in collaboration with the Genome Institute at Washington University in St. Louis , [ 23 ] [ 24 ] so that C. elegans became the first animal to have its complete genome sequenced. [ 25 ]
Sulston played a central role in both the C. elegans [ 7 ] and human genome [ 26 ] sequencing projects. He had argued successfully for the sequencing of C. elegans to show that large-scale genome sequencing projects were feasible. As sequencing of the worm genome proceeded, the Human Genome Project began. At this point he was made director of the newly established Sanger Centre (named after Fred Sanger [ 27 ] ), located in Cambridgeshire , England.
In 2000, after the 'working draft' of the human genome sequence was completed, Sulston retired from directing the Sanger Centre. With Georgina Ferry, he narrated his research career leading to the human genome sequence in The Common Thread: A Story of Science, Politics, Ethics, and the Human Genome (2002). [ 28 ]
Sulston was elected a Fellow of the Royal Society (FRS) in 1986 . [ 1 ] His certificate of election reads:
John Sulston is distinguished for his work on the molecular and developmental genetics of Caenorhabditis elegans . His initial research was in the field of chemical synthesis of oligonucleotides. Sulston began his work on C. elegans in 1974 characterising its DNA. Since then he has carried out a wide range of genetical and developmental studies on the nematode but his major research has been on the developmental lineage and mutations that affect it. In a series of studies, culminating in a paper published in 1983, Sulston has analysed and described the total cell lineage of the nematode making it the first organism for which the origin of every cell is exactly known. This work is the basis for the study of mutations affecting lineages and is the foundation on which detailed studies of development in this organism will be based. Sulston has now turned his attention to an analysis of the genome of C. elegans and was constructing a total physical map using a novel method of analysing cloned DNA fragments. [ 29 ]
He was elected an EMBO Member in 1989 [ 30 ] and awarded the George W. Beadle Award in 2000. [ 2 ] In 2001 Sulston gave the Royal Institution Christmas Lectures on The Secrets of Life . In 2002, he won the Dan David Prize and the Robert Burns Humanitarian Award . Later, he shared the Nobel Prize in Physiology or Medicine [ 31 ] with Sydney Brenner and Robert Horvitz , both of whom he had collaborated with at the MRC Laboratory of Molecular Biology (LMB) , for their discoveries concerning 'genetic regulation of organ development and programmed cell death'.
One of Sulston's most important contributions during his research years at the LMB was to elucidate the precise order in which cells in C. elegans divide. In fact, he and his team succeeded in tracing the nematode's entire embryonic cell lineage. [ 8 ]
In 2004, Sulston received the Golden Plate Award of the American Academy of Achievement . [ 32 ] In 2006, he was awarded the George Dawson Prize in Genetics by Trinity College Dublin . [ 33 ] In 2013, Sulston was awarded the Royal Society of New Zealand 's Rutherford Memorial Lecture , which he gave on the subject of population pressure. [ 34 ]
He was appointed a Member of the Order of the Companions of Honour (CH) in the 2017 Birthday Honours for services to science and society. [ 35 ]
On 23 October 2017 he was awarded the Cambridge Chemistry Alumni Medal. [ 36 ]
Sulston was a leading campaigner against the patenting of human genetic information.
John Sulston met Daphne Bate, a research assistant in Cambridge. [ 18 ] They got married in 1966 [ 18 ] just before they left for US for postdoctoral research. Together they had two children. Their first child, Ingrid, was born in La Jolla in 1967, and their second, Adrian, later in England. [ 37 ] The couple lived in Stapleford, Cambridgeshire where they were active members of the local community: [ citation needed ] John regularly volunteered in the local library and in working parties at Magog Down ; he was a Trustee of Cambridge Past, Present and Future. [ 38 ] [ verification needed ]
Although brought up in a Christian family, Sulston lost his faith during his student life at Cambridge, and remained an atheist. [ 4 ] [ 19 ] He was a distinguished supporter of Humanists UK . [ 39 ] In 2003 he was one of 22 Nobel Laureates who signed the Humanist Manifesto . [ 40 ]
Sulston was in favour of free public access of scientific information. He wanted genome information freely available, and he described as "totally immoral and disgusting" the idea of profiteering from such research. He also wanted to change patent law, and argued that restrictions on drugs such as the anti-viral drug Tamiflu by Roche are a hindrance to patients whose lives are dependent on them. [ 19 ]
In December 2010, Sulston backed Julian Assange by acting as a bail surety for him, according to Assange's attorney Mark Stephens . [ 41 ] Sulston forfeited £15,000 of the £20,000 pledged in June 2012, as Assange had entered the embassy of Ecuador to escape the jurisdiction of the English courts. [ 42 ] [ 43 ]
Sulston died on 6 March 2018 of stomach cancer, aged 75 years. [ 17 ] | https://en.wikipedia.org/wiki/John_Sulston |
John Ulric Nef (née Johann Ulrich Nef ; June 14, 1862 – August 13, 1915) was a Swiss-born American chemist and the discoverer of the Nef reaction and Nef synthesis . [ 1 ] He was a member of the American Academy of Arts and Sciences and the National Academy of Sciences . [ 1 ]
His parents emigrated from Switzerland to the United States, where Nef studied chemistry at Harvard University until 1884. Upon graduation, he joined Adolf von Baeyer at the University of Munich , where he received his Ph.D. in 1887. [ 2 ]
He was a professor at Purdue University from 1887 till 1889 and at Clark University from 1889 till 1892. In 1892 Nef joined the newly formed University of Chicago as professor of chemistry, where he spent the rest of his academic career. [ 2 ] [ 1 ] He died in Carmel-by-the-Sea, California on August 13, 1915. [ 3 ]
His son John Ulric Nef (1899–1988) became a professor of economic history and published several books. [ 2 ] [ 1 ]
The discovery of the Nef reaction and the papers about divalent carbon ( carbenes ) were his major achievements. [ 2 ] [ 1 ]
This biographical article about an American chemist is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/John_Ulric_Nef_(chemist) |
John Wallis ( / ˈ w ɒ l ɪ s / ; [ 2 ] Latin : Wallisius ; 3 December [ O.S. 23 November] 1616 – 8 November [ O.S. 28 October] 1703) was an English clergyman and mathematician , who is given partial credit for the development of infinitesimal calculus .
Between 1643 and 1689 Wallis served as chief cryptographer for Parliament and, later, the royal court. [ 3 ] He is credited with introducing the symbol ∞ to represent the concept of infinity . [ 4 ] He similarly used 1/∞ for an infinitesimal . He was a contemporary of Newton and one of the greatest intellectuals of the early renaissance of mathematics . [ 5 ]
On 14 March 1645, he married Susanna Glynde ( c. 1600 – 16 March 1687). They had three children:
John Wallis was born in Ashford, Kent . He was the third of five children of Revd. John Wallis and Joanna Chapman. He was initially educated at a school in Ashford but moved to James Movat's school in Tenterden in 1625 following an outbreak of plague . Wallis was first exposed to mathematics in 1631, at Felsted School (then known as Martin Holbeach's school in Felsted); he enjoyed maths, but his study was erratic, since "mathematics, at that time with us, were scarce looked on as academical studies, but rather mechanical" ( Scriba 1970 ). At the school in Felsted , Wallis learned how to speak and write Latin . By this time, he also was proficient in French , Greek , and Hebrew . [ 9 ] As it was intended he should be a doctor, he was sent in 1632 to Emmanuel College, Cambridge . [ 10 ] While there, he kept an act on the doctrine of the circulation of the blood ; that was said to have been the first occasion in Europe on which this theory was publicly maintained in a disputation. His interests, however, centred on mathematics. He received his Bachelor of Arts degree in 1637 and a Master's in 1640, afterwards entering the priesthood. From 1643 to 1649, he served as a nonvoting scribe at the Westminster Assembly . He was elected to a fellowship at Queens' College, Cambridge in 1644, from which he had to resign following his marriage. [ citation needed ]
Throughout this time, Wallis had been close to the Parliamentarian party, perhaps as a result of his exposure to Holbeach at Felsted School. He rendered them great practical assistance in deciphering Royalist dispatches. The quality of cryptography at that time was mixed; despite the individual successes of mathematicians such as François Viète , the principles underlying cipher design and analysis were very poorly understood. Most ciphers were ad hoc methods relying on a secret algorithm , as opposed to systems based on a variable key . Wallis realised that the latter were far more secure – even describing them as "unbreakable", though he was not confident enough in this assertion to encourage revealing cryptographic algorithms. He was also concerned about the use of ciphers by foreign powers, refusing, for example, Gottfried Leibniz 's request of 1697 to teach Hanoverian students about cryptography. [ 11 ]
Returning to London – he had been made chaplain at St Gabriel Fenchurch in 1643 – Wallis joined the group of scientists that was later to evolve into the Royal Society . He was finally able to indulge his mathematical interests, mastering William Oughtred 's Clavis Mathematicae in a few weeks in 1647. He soon began to write his own treatises, dealing with a wide range of topics, which he continued for the rest of his life. Wallis wrote the first survey about mathematical concepts in England where he discussed the Hindu-Arabic system. [ 12 ]
Wallis joined the moderate Presbyterians in signing the remonstrance against the execution of Charles I , by which he incurred the lasting hostility of the Independents. In spite of their opposition he was appointed in 1649 to the Savilian Chair of Geometry at Oxford University, where he lived until his death on 8 November [ O.S. 28 October] 1703. In 1650, Wallis was ordained as a minister. After, he spent two years with Sir Richard Darley and Lady Vere as a private chaplain . In 1661, he was one of twelve Presbyterian representatives at the Savoy Conference . [ citation needed ]
Besides his mathematical works he wrote on theology , logic , English grammar and philosophy, and he was involved in devising a system for teaching a deaf boy to speak at Littlecote House . [ 13 ] William Holder had earlier taught a deaf man, Alexander Popham, to speak "plainly and distinctly, and with a good and graceful tone". [ 14 ] Wallis later claimed credit for this, leading Holder to accuse Wallis of "rifling his Neighbours, and adorning himself with their spoyls". [ 15 ]
The Parliamentary visitation of Oxford , that began in 1647, removed many senior academics from their positions, including in November 1648, the Savilian Professors of Geometry and Astronomy. In 1649 Wallis was appointed as Savilian Professor of Geometry. Wallis seems to have been chosen largely on political grounds (as perhaps had been his Royalist predecessor Peter Turner , who despite his appointment to two professorships never published any mathematical works); while Wallis was perhaps the nation's leading cryptographer and was part of an informal group of scientists that would later become the Royal Society , he had no particular reputation as a mathematician. Nonetheless, Wallis' appointment proved richly justified by his subsequent work during the 54 years he served as Savilian Professor. [ 16 ]
Wallis made significant contributions to trigonometry , calculus , geometry , and the analysis of infinite series . In his Opera Mathematica I (1695) he introduced the term " continued fraction ".
In 1655, Wallis published a treatise on conic sections in which they were defined analytically. This was the earliest book in which these curves are considered and defined as curves of the second degree . It helped to remove some of the perceived difficulty and obscurity of René Descartes ' work on analytic geometry .
In Treatise on the Conic Sections , Wallis popularised the symbol ∞ for infinity. He wrote, "I suppose any plane (following the Geometry of Indivisibles of Cavalieri) to be made up of an infinite number of parallel lines, or as I would prefer, of an infinite number of parallelograms of the same altitude; (let the altitude of each one of these be an infinitely small part 1/∞ of the whole altitude, and let the symbol ∞ denote Infinity) and the altitude of all to make up the altitude of the figure." [ 17 ]
Arithmetica Infinitorum , the most important of Wallis's works, was published in 1656. In this treatise the methods of analysis of Descartes and Cavalieri were systematised and extended, but some ideas were open to criticism. He began, after a short tract on conic sections, by developing the standard notation for powers, extending them from positive integers to rational numbers :
Leaving the numerous algebraic applications of this discovery, he next proceeded to find, by integration , the area enclosed between the curve y = x m , x -axis, and any ordinate x = h , and he proved that the ratio of this area to that of the parallelogram on the same base and of the same height is 1/( m + 1), extending Cavalieri's quadrature formula . He apparently assumed that the same result would be true also for the curve y = ax m , where a is any constant, and m any number positive or negative, but he discussed only the case of the parabola in which m = 2 and the hyperbola in which m = −1. In the latter case, his interpretation of the result is incorrect. He then showed that similar results may be written down for any curve of the form
and hence that, if the ordinate y of a curve can be expanded in powers of x , its area can be determined: thus he says that if the equation of the curve is y = x 0 + x 1 + x 2 + ..., its area would be x + x 2 /2 + x 3 /3 + ... . He then applied this to the quadrature of the curves y = ( x − x 2 ) 0 , y = ( x − x 2 ) 1 , y = ( x − x 2 ) 2 , etc., taken between the limits x = 0 and x = 1. He shows that the areas are, respectively, 1, 1/6, 1/30, 1/140, etc. He next considered curves of the form y = x 1/ m and established the theorem that the area bounded by this curve and the lines x = 0 and x = 1 is equal to the area of the rectangle on the same base and of the same altitude as m : m + 1. This is equivalent to computing
He illustrated this by the parabola, in which case m = 2. He stated, but did not prove, the corresponding result for a curve of the form y = x p / q .
Wallis showed considerable ingenuity in reducing the equations of curves to the forms given above, but, as he was unacquainted with the binomial theorem , he could not effect the quadrature of the circle , whose equation is y = 1 − x 2 {\displaystyle y={\sqrt {1-x^{2}}}} , since he was unable to expand this in powers of x . He laid down, however, the principle of interpolation . Thus, as the ordinate of the circle y = 1 − x 2 {\displaystyle y={\sqrt {1-x^{2}}}} is the geometrical mean of the ordinates of the curves y = ( 1 − x 2 ) 0 {\displaystyle y=(1-x^{2})^{0}} and y = ( 1 − x 2 ) 1 {\displaystyle y=(1-x^{2})^{1}} , it might be supposed that, as an approximation, the area of the semicircle ∫ 0 1 1 − x 2 d x {\displaystyle \int _{0}^{1}\!{\sqrt {1-x^{2}}}\,dx} which is 1 4 π {\displaystyle {\tfrac {1}{4}}\pi } might be taken as the geometrical mean of the values of
that is, 1 {\displaystyle 1} and 2 3 {\displaystyle {\tfrac {2}{3}}} ; this is equivalent to taking 4 2 3 {\displaystyle 4{\sqrt {\tfrac {2}{3}}}} or 3.26... as the value of π. But, Wallis argued, we have in fact a series 1 , 1 6 , 1 30 , 1 140 , {\displaystyle 1,{\tfrac {1}{6}},{\tfrac {1}{30}},{\tfrac {1}{140}},} ... and therefore the term interpolated between 1 {\displaystyle 1} and 1 6 {\displaystyle {\tfrac {1}{6}}} ought to be chosen so as to obey the law of this series. [ clarification needed ] This, by an elaborate method that is not described here in detail, leads to a value for the interpolated term which is equivalent to taking
(which is now known as the Wallis product ).
In this work the formation and properties of continued fractions are also discussed, the subject having been brought into prominence by Brouncker 's use of these fractions.
A few years later, in 1659, Wallis published a tract containing the solution of the problems on the cycloid which had been proposed by Blaise Pascal . In this he incidentally explained how the principles laid down in his Arithmetica Infinitorum could be used for the rectification of algebraic curves and gave a solution of the problem to rectify (i.e., find the length of) the semicubical parabola x 3 = ay 2 , which had been discovered in 1657 by his pupil William Neile . Since all attempts to rectify the ellipse and hyperbola had been (necessarily) ineffectual, it had been supposed that no curves could be rectified, as indeed Descartes had definitely asserted to be the case. The logarithmic spiral had been rectified by Evangelista Torricelli and was the first curved line (other than the circle) whose length was determined, but the extension by Neile and Wallis to an algebraic curve was novel. The cycloid was the next curve rectified; this was done by Christopher Wren in 1658. [ citation needed ]
Early in 1658 a similar discovery, independent of that of Neile, was made by van Heuraët , and this was published by van Schooten in his edition of Descartes's Geometria in 1659. Van Heuraët's method is as follows. He supposes the curve to be referred to rectangular axes; if this is so, and if ( x , y ) are the coordinates of any point on it, and n is the length of the normal, [ clarification needed ] and if another point whose coordinates are ( x , η ) is taken such that η : h = n : y , where h is a constant; then, if ds is the element of the length of the required curve, we have by similar triangles ds : dx = n : y . Therefore, h ds = η dx . Hence, if the area of the locus of the point ( x , η ) can be found, the first curve can be rectified. In this way van Heuraët effected the rectification of the curve y 3 = ax 2 but added that the rectification of the parabola y 2 = ax is impossible since it requires the quadrature of the hyperbola. The solutions given by Neile and Wallis are somewhat similar to that given by van Heuraët, though no general rule is enunciated, and the analysis is clumsy. A third method was suggested by Fermat in 1660, but it is inelegant and laborious.
The theory of the collision of bodies was propounded by the Royal Society in 1668 for the consideration of mathematicians. Wallis, Christopher Wren , and Christiaan Huygens sent correct and similar solutions, all depending on what is now called the conservation of momentum ; but, while Wren and Huygens confined their theory to perfectly elastic bodies ( elastic collision ), Wallis considered also imperfectly elastic bodies ( inelastic collision ). This was followed in 1669 by a work on statics (centres of gravity), and in 1670 by one on dynamics : these provide a convenient synopsis of what was then known on the subject.
In 1685 Wallis published Algebra , preceded by a historical account of the development of the subject, which contains a great deal of valuable information. The second edition, issued in 1693 and forming the second volume of his Opera , was considerably enlarged. This algebra is noteworthy as containing the first systematic use of formulae. A given magnitude is here represented by the numerical ratio which it bears to the unit of the same kind of magnitude: thus, when Wallis wants to compare two lengths he regards each as containing so many units of length. This perhaps will be made clearer by noting that the relation between the space described in any time by a particle moving with a uniform velocity is denoted by Wallis by the formula
where s is the number representing the ratio of the space described to the unit of length; while the previous writers would have denoted the same relation by stating what is equivalent to the proposition
Wallis has been credited as the originator of the number line "for negative quantities" [ 18 ] and "for operational purposes." [ 19 ] This is based on a passage in his 1685 treatise on algebra in which he introduced a number line to illustrate the legitimacy of negative quantities: [ 20 ]
Yet is not that Supposition (of Negative Quantities) either Unuseful or Absurd; when rightly understood. And though, as to the bare Algebraick Notation, it import a Quantity less than nothing: Yet, when it comes to a Physical Application, it denotes as Real a Quantity as if the Sign were + {\displaystyle +} ; but to be interpreted in a contrary sense... + 3 {\displaystyle +3} , signifies 3 {\displaystyle 3} Yards Forward; and − 3 {\displaystyle -3} , signifies 3 {\displaystyle 3} Yards Backward.
It has been noted that, in an earlier work, Wallis came to the conclusion that the ratio of a positive number to a negative one is greater than infinity. The argument involves the quotient 1 x {\displaystyle {\tfrac {1}{x}}} and considering what happens as x {\displaystyle x} approaches and then crosses the point x = 0 {\displaystyle x=0} from the positive side. [ 21 ] Wallis was not alone in this thinking: Leonhard Euler came to the same conclusion by considering the geometric series 1 1 − x = 1 + x + x 2 + ⋯ {\displaystyle {\tfrac {1}{1-x}}=1+x+x^{2}+\cdots } , evaluated at x = 2 {\displaystyle x=2} , followed by reasoning similar to Wallis's (he resolved the paradox by distinguishing different kinds of negative numbers). [ 18 ]
He is usually credited with the proof of the Pythagorean theorem using similar triangles . However, Thabit Ibn Qurra (AD 901), an Arab mathematician, had produced a generalisation of the Pythagorean theorem applicable to all triangles six centuries earlier. It is a reasonable conjecture that Wallis was aware of Thabit's work. [ 22 ]
Wallis was also inspired by the works of Islamic mathematician Sadr al-Tusi, the son of Nasir al-Din al-Tusi , particularly by al-Tusi's book written in 1298 on the parallel postulate . The book was based on his father's thoughts and presented one of the earliest arguments for a non-Euclidean hypothesis equivalent to the parallel postulate. After reading this, Wallis then wrote about his ideas as he developed his own thoughts about the postulate, trying to prove it also with similar triangles. [ 23 ]
He found that Euclid's fifth postulate is equivalent to the one currently named "Wallis postulate" after him. This postulate states that "On a given finite straight line it is always possible to construct a triangle similar to a given triangle". This result was encompassed in a trend trying to deduce Euclid's fifth from the other four postulates which today is known to be impossible. Unlike other authors, he realised that the unbounded growth of a triangle was not guaranteed by the four first postulates. [ 24 ]
Another aspect of Wallis's mathematical skills was his ability to do mental calculations. He slept badly and often did mental calculations as he lay awake in his bed. One night he calculated in his head the square root of a number with 53 digits. In the morning he dictated the 27-digit square root of the number, still entirely from memory. It was a feat that was considered remarkable, and Henry Oldenburg , the Secretary of the Royal Society, sent a colleague to investigate how Wallis did it. It was considered important enough to merit discussion in the Philosophical Transactions of the Royal Society of 1685. [ 25 ] [ 26 ]
Wallis translated into Latin works of Ptolemy and Bryennius, and Porphyrius's commentary on Ptolemy. He also published three letters to Henry Oldenburg concerning tuning. He approved of equal temperament , which was being used in England's organs. [ 27 ]
His Institutio logicae , published in 1687, was very popular. [ 4 ] The Grammatica linguae Anglicanae was a work on English grammar , that remained in print well into the eighteenth century. He also published on theology. [ 4 ]
While employed as lady Vere's chaplain in 1642 Wallis was given an enciphered letter about the fall of Chicester which he managed to decipher within two hours. This started his career as a cryptographer. He was a moderate supporter of the Parliamentarian side in the First English Civil War and therefore worked as a decipherer of intercepted correspondence for the Parliamentarian leaders. For his services he was rewarded with the Livings of St. Gabriel and St. Martin's in London . [ 28 ]
Because of his Parliamentarian sympathies Wallis was not employed as a cryptographer after the Stuart Restoration , [ 29 ] but after the Glorious Revolution he was sought out by lord Nottingham and frequently employed to decipher encrypted intercepted correspondence, though he thought that he was not always adequately rewarded for his work. [ a ] King William III from 1689 also employed Wallis as a cryptographer, sometimes almost on a daily basis. Couriers would bring him letters to be decrypted and waited in front of his study for the product. The king took a personal interest in Wallis' work and well-being as witnessed by a letter he sent to Dutch Grand pensionary Anthonie Heinsius in 1689. [ 29 ]
In these early days of the Williamite reign directly obtaining foreign intercepted letters was a problem for the English, as they did not have the resources of foreign Black Chambers as yet, but allies like the Elector of Brandenburg without their own Black Chambers occasionally made gifts of such intercepted correspondence, like the letter of king Louis XIV of France to king John III Sobieski of Poland that king William in 1689 used to cause a crisis in French-Polish diplomatic relations. He was quite open about it and Wallis was rewarded for his role. [ 31 ] But Wallis became nervous that the French might take action against him. [ 32 ]
Wallis relationship with the German mathematician Gottfried Wilhelm Leibniz was cordial. But Leibniz also had cryptographic interests and tried to get Wallis to divulge some of his trade secrets, which Wallis declined to do as a matter of patriotic principle. [ 33 ]
Smith gives an example of the painstaking work that Wallis performed, as described by himself in a letter to Richard Hampden of 3 August 1689. In it he gives a detailed account of his work on a particular letter and the parts he had encountered difficulties with. [ 34 ]
Wallis' correspondence also shows details of the way he stood up for himself, when he thought he was under-appreciated, financially or otherwise. He lobbied enthusiastically, both on his own behalf, and that of his relatives, as witnessed by letters to Lord Nottingham, Richard Hampden and the MP Harbord Harbord that Smith quotes. [ 35 ] In a letter to the English envoy to Prussia, James Johnston Wallis bitterly complains that a courtier of the Prussian Elector, by the name of Smetteau, had done him wrong in the matter of just compensation for services rendered to the Elector. In the letter he gives details of what he had done and gives advice on a simple substitution cipher for the use of Johnston himself. [ 36 ]
Wallis' contributions to the art of cryptography were not only of a "technological" character. De Leeuw points out that even the "purely scientific" contributions of Wallis to the science of linguistics in the field of the "rationality" of Natural language as it developed over time, played a role in the development of cryptology as a science. Wallis' development of a model of English grammar, independent of earlier models based on Latin grammar, is a case in point of the way other sciences helped develop cryptology in his view. [ 37 ]
Wallis tried to teach his own son John, and his grandson by his daughter Anne, William Blencowe the tricks of the trade. With William he was so successful that he could persuade the government to allow the grandson to get the survivorship of the annual pension of £100 Wallis had received in compensation for his cryptographic work. [ 38 ]
William Blencowe eventually succeeded Wallis as official Cryptographer to Queen Anne after Wallis' death in 1703. [ 39 ] | https://en.wikipedia.org/wiki/John_Wallis |
John Wesley Young (17 November 1879, Columbus, Ohio – 17 February 1932, Hanover, New Hampshire ) was an American mathematician who, with Oswald Veblen , introduced the axioms of projective geometry , coauthored a 2-volume work on them, and proved the Veblen–Young theorem . He was a proponent of Euclidean geometry and held it to be substantially "more convenient to employ" than non-Euclidean geometry . [ 1 ] His lectures on algebra and geometry were compiled in 1911 and released as Lectures on Fundamental Concepts of Algebra and Geometry.
John Wesley Young was born in 1879 to William Henry Young and Marie Louise Widenhorn Young. William Henry Young was from West Virginia and was of Native American parentage. After serving in the Civil War he was appointed to the consulate in Germany. He taught Mathematics at Ohio University. Marie Louise Widehorn Young was born in Paris, France and spoke French and German fluently. [ 2 ]
John Wesley grew up in both Europe and America due to his father's profession and attended schools in Baden Baden and Karlsruhe , Germany and Columbus , Ohio . Young was awarded a Master's degree in Mathematics from Cornell University in 1903.
John Wesley Young was married to Mary Louise Aston on July 20, 1907. They had one daughter, Mary Elizabeth, later Mrs. Allyn. [ 2 ]
Between 1903 and 1911, Young held positions at Northwestern University , Princeton University , the University of Illinois , the University of Kansas , and the University of Chicago . He was head of the department of Mathematics at Dartmouth College from 1911 to 1919 and chair of the department from 1923 to 1925. He continued teaching until two days before he died. [ 3 ]
This article about an American mathematician is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/John_Wesley_Young |
John Whitby Allen (July 2, 1913 – January 6, 1973) was a prominent American model railroader . He pioneered or developed several aspects of the hobby on his HO scale Gorre & Daphetid model railroad in Monterey, California , popularizing them with numerous magazine articles and photographs starting in the 1940s.
Allen was renowned for his skill at scratch building and creating scenery. He also pioneered the technique of weathering his models for a more realistic appearance. In addition to his superdetailing of locomotives, rolling stock , structures, and scenery, Allen was known for populating his model world with scale figures in humorous scenes. Other techniques Allen promoted were realistic train operation and the use of forced perspective to create the illusion of a model railroad layout larger than it really was.
Born in Joplin, Missouri , Allen lost his father to typhoid fever when he was three; his mother died during the flu epidemic about nine years later. Allen lived with relatives in Missouri until attending school in Minnesota. While there, he developed rheumatic fever , and on the advice of a doctor, moved to California to live with an aunt and uncle. His health improved, but the rheumatic fever weakened his heart.
After completing high school, Allen attended UCLA , and joined the Reserve Officers' Training Corps (ROTC). He became comfortable around military people, and later recruited servicemen to help run the Gorre & Daphetid.
In 1934, Allen and his brother went to the World's Fair in Chicago, and saw scale model trains in operation, and he was impressed. He was attending UCLA studying economics, but switched to art school, which he attended for three years, specializing in photography. There he acquired the skills that set his layout and model photography apart.
In 1935, John's paternal grandparents died, leaving him about $1,900 ($43,575 today [ 1 ] ), then the equivalent of a year's salary for a middle-class man. John invested the money with the help of his brother, and in about 11 years, the value was such that he did not have to work. His investments, combined with a frugal lifestyle, resulted in a sum of over $500,000 at the time of his death.
After completing school, John and another student opened a photography business in the Westlake Park area of Los Angeles.
Before World War II , Allen and his brother Andrew visited an uncle living near Oakland who had a model railroad. He became interested in working on it.
When the U.S. entered the war, Andrew joined the military and John offered his services as a photo analyst .
Allen came to Monterey, California , to visit his brother, and decided to stay. He opened a new photography shop on the main street with partner Weston Booth, and did a brisk business photographing servicemen. In 1946, John sold his business, invested the money, and retired.
Allen said that he got into model railroading just before the end of the war. Due to a limited supply of hobby materials, he began building things from scratch. He spent a lot of time studying and observing railroads in operation, and how prototype equipment was built. Allen built models, then meticulously arranged and photographed them.
In July 1946, he published the first of many articles and photographs to appear in Model Railroader magazine: "How to make realistic model photos." [ 2 ] Another photo was used for the cover of the December 1947 issue of Railroad Model Craftsman. [ 3 ]
Over the next three decades, Allen produced many articles and photographs for prominent hobby magazines. His last feature article for a major model railroad magazine likely appeared in the March and April 1971 issues of Railroad Model Craftsman. [ 3 ]
Allen also devised or inspired trends and ideas in the hobby. In 1948, his two-stall enginehouse took first award in the national model-railroading contest in the structures category. Wrote Westcott: "It aroused comment because John had modeled pigeons and their evidences along the ridge of the roof. Pigeons and other animate detail, once considered un-acceptable in this hobby, were given another look; and many a modeler began to humanize his railroad. While ' weathering ' was not entirely new, the work of Allen and a few others in this period showed how effective it could be in adding atmosphere to otherwise very stiff-looking modelwork. This also created a trend." [ 2 ]
Allen also devised " Timesaver ", a well-known model railroad switching puzzle . [ 4 ] [ 5 ]
Allen's model railroad, the HO scale Gorre & Daphetid, has been called "the world's most famous model railroad." Allen built three versions, each larger than the last. [ 6 ]
He moved into a house in 1946 and began construction of the first version of the Gorre & Daphetid. (The name is a play on words; pronounced "Gory and Defeated.") In 1953 he needed more space, and decided to move. He offered a railroad for sale, with free house. When no one was interested in buying the house with the railroad, he dismantled it. The original 3.5 ft (1.1 m) by 6.5 ft (2.0 m) G&D was saved and incorporated into the final version, while other parts were given to friends.
Allen moved to his final house, chosen for its unfinished basement. He excavated the basement, poured a concrete floor and prepared it for construction of the final layout. He allocated about half the 1,200 sq ft (110 m 2 ) to the layout, with the remainder used as workshop and storage.
Allen built a scale model of the house to aid in planning, in addition to models of the layout he planned to build. His planning was very thorough. Early plans included the use of real water in scale rivers and lakes. Construction began in January 1954. One feature of the layout was Devil's Gulch, a part of the basement not excavated, but shaped, with concrete poured over it. Allen constructed the layout almost completely by himself. He devoted the next 20 years to this project.
During this period, Allen revolutionized model railroading with realistic operations, lighting (including night lighting), and weathering of models. He used forced perspective to enhance the illusion of realism, and only allowed photography under his conditions.
John Allen suffered at least one heart attack in the 1960s. As his health declined, he continued to work to complete the Gorre & Daphetid. In a telephone conversation with Linn Westcott , he suggested that he would drive the last spike in the spring of 1973, and that Linn should come for a visit then. In 1972, he was already suggesting that things might not be going well, and wondering "what to do with the railroad" in letters to a friend. He suffered a fatal heart attack on the evening of January 6, 1973.
Ten days after Allen died, some of his friends gathered for an operating session and discussion on the preservation of the railroad in accordance with Allen's wishes.
When they left, someone set a small gas furnace in the train room to 65 °F. Allen had rarely used the furnace, because he liked to keep the house cool, or possibly because it was not vented correctly. He had covered it with tar paper .
This caused a fire, investigators later determined, according to Linn Westcott's book Model Railroading with John Allen. The fire was quickly reported and extinguished fast enough to save the house, but it destroyed the final, still-unfinished incarnation of Allen's railroad. Linn Westcott was asked by John's brother Andrew Allen to see whether the layout could be salvaged. They tried to save the "French Gulch" section, but it collapsed as they moved it after two hours of work.
The damage was mainly contained to the layout room, and the house was rehabilitated and sold.
A few model railroad items attributed to Allen survive and have been authenticated.
The first wide public mention of Allen's death was an obituary penned by editor Tony Koester in the March 1973 issue of Railroad Model Craftsman . [ 3 ] "John Allen was an institution, Although his material had appeared in print on countless occasions (the December 1947 issue of Railroad Model Craftsman featured a John Allen cover), reader enthusiasm for his well known HO scale Gorre & Daphetid never wore down," Koester wrote. "The hobby has lost an all-time great." [ 3 ]
The April 1973 issue of Model Railroader magazine contained an obituary by editor Linn Westcott and a cover photo of Allen. [ 2 ]
The January 2003 issue of Model Railroader contained a remembrance of him 30 years after his death.
Former Model Railroader editor Linn Westcott's final book, entitled Model Railroading with John Allen , was published posthumously in 1981. Westcott died in 1980 while writing the book. It contained various quotes and photographs from Allen demonstrating his techniques.
There is a video about John Allen's railroad by Sunday River Productions called The Gorre & Daphetid [ 7 ] with footage shot by Richard Reynolds with a small intro by Glenn Beier who also operated on the G&D. Glenn Beier says "it is the only motion picture ever made of the world's most famous model railroad". Until February 2007, only a VHS copy of the video was for sale. Now both VHS and DVD versions are available. | https://en.wikipedia.org/wiki/John_Whitby_Allen |
John William Draper (May 5, 1811 – January 4, 1882) was an English scientist, philosopher, physician, chemist , historian and photographer. He is credited with pioneering portrait photography (1839–40) and producing the first detailed photograph of the moon in 1840. He was also the first president of the American Chemical Society (1876–77) and a founder of the New York University School of Medicine .
One of Draper's books, the History of the Conflict between Religion and Science , popularised the conflict thesis proposing intrinsic hostility in the relationship between religion and science . It was widely read and was translated into several languages. [ 1 ]
His son, Henry Draper , and his granddaughter, Antonia Maury , were astronomers. His granddaughter, Carlotta Maury (Antonia's younger sister), was a paleontologist. His eldest son, John Christopher Draper , was a chemist; and son Daniel Draper , a meteorologist. [ 2 ]
John William Draper was born May 5, 1811, in St. Helens , Lancashire, England, [ 3 ] to John Christopher Draper, a Wesleyan clergyman, and Sarah (Ripley) Draper. He also had three sisters, Dorothy Catherine Draper (August 6, 1807 – December 10, 1901), [ 4 ] Elizabeth Johnson, and Sarah Ripley. On June 23, he was baptized by the Wesleyan Methodist minister Jabez Bunting . His father often needed to move the family due to serving various congregations throughout England. John Wm. Draper was home tutored until 1822, when he entered Woodhouse Grove School . He returned to home instruction (1826) prior to entering University College London in 1829. [ 5 ] While at University College London , Draper studied chemistry under the direction of Edward Turner (chemist) . [ 6 ]
On September 13, 1831, John William Draper married Antonia Caetana de Paiva Pereira Gardner ( c. 1814 –1870), the daughter of Daniel Gardner, a court physician to John VI of Portugal and Charlotte of Spain . Antonia was born in Brazil after the royal family fled Portugal with Napoleon 's invasion . There is dispute as to the identity of Antonia's mother. Around 1830, Antonia was sent with her brother Daniel to live with their aunt in London. [ 7 ]
Following his father's death in July 1831, John William's mother was urged to move with her children to the US state of Virginia . John William hoped to acquire a teaching position at a local Methodist college. [ 8 ]
In 1832, the family settled in Mecklenburg County, Virginia , 7 miles (11 km) east of Christiansville (now Chase City ). Although he arrived too late to obtain the prospective teaching position, John William established a laboratory in Christiansville. Here he conducted experiments and published eight papers before entering medical school. His sister Dorothy Catherine Draper provided finances through teaching drawing and painting for his medical education. In March 1836, he graduated from the University of Pennsylvania School of Medicine . That same year, he began teaching at Hampden–Sydney College in Virginia . [ 9 ]
In 1837, Draper accepted an appointment to be head of chemistry in a proposed medical school at New York University , but sufficient funds were not available to go ahead with the project. In 1839, Draper was elected undergraduate professor of chemistry and botany at the university, and moved with his family to New York City . [ 10 ] Once there he helped to found the New York University Medical School , acting as a professor there from 1840 to 1850, president of the school from 1850 to 1873, and as a professor of chemistry until 1881.
Draper did important research in photochemistry , made portrait photography possible by his improvements (1839) on Louis Daguerre's process , and published Organization of Plants (1844), a textbook on Chemistry (1846), textbook on Natural Philosophy (1847), textbook on Physiology (1866), and Scientific Memoirs (1878) on radiant energy .
In the spring of 1839, Draper, with years of experience in photochemistry, took Talbotype photographs at Hampden Sydney College in Virginia. However, he was dissatisfied with the results and decided to wait for the publication of the daguerreotype process. Once the details of the process arrived in America in late September 1839, Draper, now a professor at New York University , captured landscape photographs. On or around September 23, he took one of the earliest daguerreotype portraits, which depicted his assistant, William Henry Goode. [ 11 ] [ 12 ]
Throughout 1839 and 1840, Draper focused on solving the challenge of creating daguerreotype portraits. He collaborated with Samuel Morse and in spring 1840 operated a daguerreotype studio, one of the earliest of its kind, in a building on the roof of the New York University . [ 13 ] Draper also photographed his sister, Dorothy Catherine Draper , and one of those pictures (see image) became known to the public via the letter which Draper sent to John Herschel in 1840. Several copies were made of this picture in the 19th century, and the photograph attached with Draper's letter was also likely a copy made by Draper himself. [ 4 ] [ 14 ]
In March 1840 Draper became the second person to produce photographs of an astronomical object, the Moon , considered the first astrophotographs . [ 15 ] In 1843 he made daguerreotypes of the solar spectrum that revealed new infra-red and ultra violet lines. [ 16 ] In 1850 he was making photomicrographs and engaged his son, Henry (then 13 years old), into their production.
Draper developed the proposition in 1842 that only light rays that are absorbed can produce chemical change. [ 17 ] It came to be known as the Grotthuss–Draper law when his name was teamed with a prior but apparently unknown promulgator Theodor Grotthuss of the same idea in 1817.
In 1847 he published the observation that all solids glow red at about the same temperature, about 977 °F (798 K), which has come to be known as the Draper point . [ 18 ] [ 19 ]
On Saturday 30 May the 1860 Oxford evolution debate featured Draper's lecture on his paper "On the Intellectual Development of Europe, considered with reference to the views of Mr. Darwin and others, that the progression of organisms is determined by law." Draper's presentation was an early example of applying a Darwinian metaphor of adaptation and environment to social and political studies, but was thought to be long and boring. The hall was crowded to hear Bishop Samuel Wilberforce 's views on Charles Darwin 's recent publication of On the Origin of Species , and the occasion was a historically significant part of the reaction to Darwin's theory due to reports of Thomas Henry Huxley 's response to Wilberforce. [ 20 ] [ 21 ]
Contributions to the discipline of history: Draper is well known also as the author of The History of the Intellectual Development of Europe (1862), applying the methods of physical science to history, a History of the American Civil War (3 vols., 1867–1870), and a History of the Conflict between Religion and Science (1874). [ 2 ] The last book listed is among the most influential works on the conflict thesis , which takes its name from Draper's title. His book examined the relationship between religion and science , dismissing ideas of harmony and presenting the history of science as "not a mere record of isolated discoveries; it is a narrative of the conflict of two contending powers, the expansive force of the human intellect on the one side, and the compression arising from traditional faith and human interests on the other." After outlining the origins of science in ancient Greek philosophy , Draper presented the development of Christianity as leading to repression of science. His argument, aimed at his fellow Protestants, employed anti-Catholic rhetoric, but also said that these "two rival divisions of the Christian church" were "in accord on one point: to tolerate no science except such as they considered agreeable to the Scriptures", and both were liable to "theological odium". The book went through fifty printings in the United States alone, and was translated into ten languages. [ 1 ] Professor Ronald Numbers has pointed to Draper's book as a source of popular misconceptions about historical conflict between science and religion, saying that it was "less of a dispassionate history, which it wasn't, than a screed against Roman Catholics" motivated by personal animus at the behavior of his sister, a Catholic nun, regarding the death of his son. [ 22 ]
Draper was elected a member of the American Philosophical Society in 1844. [ 23 ] He served as the first president of the American Chemical Society in 1876. [ 24 ] He was elected to the National Academy of Sciences in 1877. [ 25 ]
He died on January 4, 1882, at his home in Hastings-on-Hudson, New York , at the age of 70. [ 26 ] The funeral was held at St Mark's Church in-the-Bowery in New York City. He was buried in Green-Wood Cemetery , Brooklyn, New York . [ 27 ]
In 1975, Draper's house, known as the Henry Draper Observatory , in Hastings was designated a National Historic Landmark .
In 1976, New York University founded the John W. Draper Interdisciplinary Master's Program in Humanities and Social Thought (Draper Program) [ 28 ] in honor of his lifelong commitment to interdisciplinary study.
In 2001, Draper and the founding of the American Chemical Society were designated a National Historic Chemical Landmark at New York University . [ 29 ]
Draper wrote a number of books and articles for magazines and journals ( Google Scholar ). His books include: | https://en.wikipedia.org/wiki/John_William_Draper |
The John William Strutt, Lord Rayleigh Medal and Prize is an award of the UK-based Institute of Physics (IOP) for "distinguished contributions to theoretical (including mathematical and computational) physics". The award, named in honour of Lord Rayleigh , consists of a medal with £1,000 and a certificate. [ 1 ]
The John William Strutt, Lord Rayleigh Medal and Prize (established in 2008) [ 2 ] should not be confused with the Rayleigh Medal , which was established by the Institute of Acoustics in 1970. | https://en.wikipedia.org/wiki/John_William_Strutt,_Lord_Rayleigh_Medal_and_Prize |
The John von Neumann Computer Society ( Hungarian : Neumann János Számítógép-tudományi Társaság ) is the central association for Hungarian researchers of Information communication technology [ 1 ] and official partner of the International Federation for Information Processing [ 2 ] founded in 1968.
This computing article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/John_von_Neumann_Computer_Society |
Johnjoe McFadden (born 17 May 1956) is an Anglo-Irish scientist, academic and writer. He is Professor of Molecular Genetics at the University of Surrey , United Kingdom.
McFadden was born in Donegal, Ireland but raised in the UK . He holds joint British and Irish Nationality . He obtained his BSc in Biochemistry University of London in 1977 and his PhD at Imperial College London in 1982. He went on to work on human genetic diseases and then infectious diseases , at St Mary's Hospital Medical School , London (1982–84) and St George's Hospital Medical School , London (1984–88) and then at the University of Surrey in Guildford , UK.
For more than a decade, McFadden has researched the genetics of microbes such as the agents of tuberculosis and meningitis and invented a test for the diagnosis of meningitis. He has published more than 100 articles in scientific journals on subjects as wide-ranging as bacterial genetics, tuberculosis, idiopathic diseases and computer modelling of evolution . He has contributed to more than a dozen books and has edited a book on the genetics of mycobacteria . He produced a widely reported artificial life computer model which modelled evolution in organisms.
McFadden has lectured extensively in the UK, Europe, the US and Japan and his work has been featured on radio, television and national newspaper articles particularly for the Guardian . His present post, which he has held since 2001, is Professor of Molecular Genetics at the University of Surrey. Living in London, he is married and has one son.
McFadden wrote the popular science book, Quantum Evolution . [ 1 ] The book examines the role of quantum mechanics in life, evolution and consciousness . The book has been described as offering an alternative evolutionary mechanism, beyond the neo-Darwinian framework. [ 2 ]
The book received positive reviews by Kirkus Reviews and Publishers Weekly . [ 3 ] [ 4 ] It was negatively reviewed in the journal Heredity by evolutionary biologist Wallace Arthur . [ 5 ]
In 2006 McFadden co-edited the book, Human Nature: Fact and Fiction on the insights of both science and literature on human nature, with contributions from Ian McEwan , Philip Pullman , Steven Pinker , A.C. Grayling and others. [ 6 ]
in 2014 McFadden co-wrote the popular science book, Life on the Edge: The Coming Age of Quantum Biology , in which he and Jim Al-Khalili further explore quantum biology and particularly recent findings in photosynthesis, enzyme catalysis, avian navigation, olfaction, mutation and neurobiology. [ 7 ] The book received positive reviews, for example:
McFadden regularly writes articles for The Guardian newspaper [ 8 ] on topics as varied as quantum mechanics, evolution and genetically modified crops , and has reviewed books there. The Washington Post and Frankfurter Allgemeine Sonntagszeitung have also published his articles. | https://en.wikipedia.org/wiki/Johnjoe_McFadden |
The Johnsen–Rahbek effect occurs when an electric potential is applied across the boundary between a metallic surface and the surface of a semiconducting material or a polyelectrolyte . Under these conditions an attractive force appears, whose magnitude depends on the voltage and the specific materials involved. The attractive force is much larger than would be produced by Coulombic attraction.
The effect is named after Danish engineers F. A. Johnsen and K. Rahbek, the first to investigate the effect at length.
This classical mechanics –related article is a stub . You can help Wikipedia by expanding it .
This electricity-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Johnsen–Rahbek_effect |
Johnson's figure of merit is a measure of suitability of a semiconductor material for high frequency power transistor applications and requirements. More specifically, it is the product of the charge carrier saturation velocity in the material and the electric breakdown field under same conditions, first proposed by Edward O. Johnson of RCA in 1965. [ 1 ]
Note that this figure of merit (FoM) is applicable to both field-effect transistors (FETs), and with proper interpretation of the parameters, also to bipolar junction transistors (BJTs).
[ 2 ]
JFM figures vary wildly between sources – see external links and talk page.
This article about materials science is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Johnson's_figure_of_merit |
In structural engineering , Johnson's parabolic formula is an empirically based equation for calculating the critical buckling stress of a column . The formula was developed by John Butler Johnson in 1893 as an alternative to Euler's critical load formula under low slenderness ratio (the ratio of radius of gyration to effective length) conditions. [ 1 ] The equation interpolates between the yield stress of the material to the critical buckling stress given by Euler's formula relating the slenderness ratio to the stress required to buckle a column.
Buckling refers to a mode of failure in which the structure loses stability. It is caused by a lack of structural stiffness. [ 2 ] Placing a load on a long slender bar may cause a buckling failure before the specimen can fail by compression. [ 3 ]
Eulers formula for buckling of a slender column gives the critical stress level to cause buckling but doesn't consider material failure modes such as yield which has been shown to lower the critical buckling stress. Johnson's formula interpolates between the yield stress of the column material and the critical stress given by Euler's formula. It creates a new failure border by fitting a parabola to the graph of failure for Euler buckling using
There is a transition point on the graph of the Euler curve, located at the critical slenderness ratio. At slenderness values lower than this point (occurring in specimens with a relatively short length compared to their cross section), the graph will follow the Johnson parabola; in contrast, larger slenderness values will align more closely with the Euler equation.
Euler's formula is
where
Euler's equation is useful in situations such as an ideal pinned-pinned column, or in cases in which the effective length can be used to adjust the existing formula (ie. Fixed-Free). [ 4 ]
(L is the original length of the specimen before the force was applied.)
However, certain geometries are not accurately represented by the Euler formula. One of the variables in the above equation that reflects the geometry of the specimen is the slenderness ratio, which is the column's length divided by the radius of gyration. [ 5 ]
The slenderness ratio is an indicator of the specimen's resistance to bending and buckling, due to its length and cross section. If the slenderness ratio is less than the critical slenderness ratio, the column is considered to be a short column. In these cases, the Johnson parabola is more applicable than the Euler formula. [ 6 ] The slenderness ratio of the member can be found with ( l k ) = L e A I {\displaystyle \left({\frac {l}{k}}\right)=L_{e}{\sqrt {A \over I}}}
The critical slenderness ratio is
One common material in aerospace applications is aluminum 2024. Certain material properties of aluminum 2024 have been determined experimentally, such as the tensile yield strength (324 MPa) and the modulus of elasticity (73.1 GPa). [ 7 ] The Euler formula could be used to plot a failure curve, but it would not be accurate below a certain l k {\displaystyle {\frac {l}{k}}} value, the critical slenderness ratio.
Therefore, the Euler equation is applicable for values of l k {\displaystyle {\frac {l}{k}}} greater than 66.7.
Johnson's parabola takes care of the smaller l k {\displaystyle {\frac {l}{k}}} values. | https://en.wikipedia.org/wiki/Johnson's_parabolic_formula |
Johnson Matthey Technology Review , known as Platinum Metals Review before 2014, is a quarterly, open access , peer-reviewed scientific journal publishing reports on scientific research on the platinum group metals and related industrial developments. [ 1 ]
The journal was established in 1957 under the name Platinum Metals Review and was published by Johnson Matthey and Co. , [ 2 ] [ 3 ] with the support of the Rustenburg Platinum Mines . [ 4 ] This was done in the hopes of increasing the availability of information on the properties of Platinum and to link both academic and industrial research with "the aims of finding practical solutions to the material problems of modern technology (McDonald/Hunt)". [ 4 ] From the July 2004 issue onward, it was published in electronic format only. [ 5 ] In 2014 the journal was relaunched as Johnson Matthey Technology Review . [ 6 ] [ 7 ]
The journal included reviews of research, books, and academic conferences , as well as primary results in the form of brief reports. It also reviewed what it considered to be notable aspects of patents and relevant scientific literature . Occasionally articles on the history, geological occurrences, and exploitation of platinum group metals were also published. [ 8 ]
While between 2016 and October 2022 the journals content was published as CC BY-NC-ND 4.0 , the journal is now published under CC-BY 4.0 from January 2023 onward, in accordance with the definition of open access given by the Budapest Open Access Initiative . [ 9 ]
Currently, Johnson Matthey Technology Review was abstracted and indexed by: [ 6 ]
While it was still known as Platinum Metals Review , it was abstracted and indexed by: [ 6 ] | https://en.wikipedia.org/wiki/Johnson_Matthey_Technology_Review |
In applied mathematics, the Johnson bound (named after Selmer Martin Johnson ) is a limit on the size of error-correcting codes , as used in coding theory for data transmission or communications.
Let C {\displaystyle C} be a q -ary code of length n {\displaystyle n} , i.e. a subset of F q n {\displaystyle \mathbb {F} _{q}^{n}} . Let d {\displaystyle d} be the minimum distance of C {\displaystyle C} , i.e.
where d ( x , y ) {\displaystyle d(x,y)} is the Hamming distance between x {\displaystyle x} and y {\displaystyle y} .
Let C q ( n , d ) {\displaystyle C_{q}(n,d)} be the set of all q -ary codes with length n {\displaystyle n} and minimum distance d {\displaystyle d} and let C q ( n , d , w ) {\displaystyle C_{q}(n,d,w)} denote the set of codes in C q ( n , d ) {\displaystyle C_{q}(n,d)} such that every element has exactly w {\displaystyle w} nonzero entries.
Denote by | C | {\displaystyle |C|} the number of elements in C {\displaystyle C} . Then, we define A q ( n , d ) {\displaystyle A_{q}(n,d)} to be the largest size of a code with length n {\displaystyle n} and minimum distance d {\displaystyle d} :
Similarly, we define A q ( n , d , w ) {\displaystyle A_{q}(n,d,w)} to be the largest size of a code in C q ( n , d , w ) {\displaystyle C_{q}(n,d,w)} :
Theorem 1 (Johnson bound for A q ( n , d ) {\displaystyle A_{q}(n,d)} ):
If d = 2 t + 1 {\displaystyle d=2t+1} ,
If d = 2 t + 2 {\displaystyle d=2t+2} ,
Theorem 2 (Johnson bound for A q ( n , d , w ) {\displaystyle A_{q}(n,d,w)} ):
(i) If d > 2 w , {\displaystyle d>2w,}
(ii) If d ≤ 2 w {\displaystyle d\leq 2w} , then define the variable e {\displaystyle e} as follows. If d {\displaystyle d} is even, then define e {\displaystyle e} through the relation d = 2 e {\displaystyle d=2e} ; if d {\displaystyle d} is odd, define e {\displaystyle e} through the relation d = 2 e − 1 {\displaystyle d=2e-1} . Let q ∗ = q − 1 {\displaystyle q^{*}=q-1} . Then,
where ⌊ ⌋ {\displaystyle \lfloor ~~\rfloor } is the floor function .
Remark: Plugging the bound of Theorem 2 into the bound of Theorem 1 produces a numerical upper bound on A q ( n , d ) {\displaystyle A_{q}(n,d)} . | https://en.wikipedia.org/wiki/Johnson_bound |
In mathematics, the Johnson scheme , named after Selmer M. Johnson , is also known as the triangular association scheme . It consists of the set of all binary vectors X of length ℓ and weight n , such that v = | X | = ( ℓ n ) {\displaystyle v=\left|X\right|={\binom {\ell }{n}}} . [ 1 ] [ 2 ] [ 3 ] Two vectors x , y ∈ X are called i th associates if dist( x , y ) = 2 i for i = 0, 1, ..., n . The eigenvalues are given by
where
and E k ( x ) is an Eberlein polynomial defined by
This combinatorics -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Johnson_scheme |
In solid mechanics , the Johnson–Holmquist damage model is used to model the mechanical behavior of damaged brittle materials, such as ceramics , rocks , and concrete , over a range of strain rates . Such materials usually have high compressive strength but low tensile strength and tend to exhibit progressive damage under load due to the growth of microfractures .
There are two variations of the Johnson-Holmquist model that are used to model the impact performance of ceramics under ballistically delivered loads. [ 1 ] These models were developed by Gordon R. Johnson and Timothy J. Holmquist in the 1990s with the aim of facilitating predictive numerical simulations of ballistic armor penetration. The first version of the model is called the 1992 Johnson-Holmquist 1 (JH-1) model. [ 2 ] This original version was developed to account for large deformations but did not take into consideration progressive damage with increasing deformation; though the multi-segment stress-strain curves in the model can be interpreted as incorporating damage implicitly. The second version, developed in 1994, incorporated a damage evolution rule and is called the Johnson-Holmquist 2 (JH-2) model [ 3 ] or, more accurately, the Johnson-Holmquist damage material model.
The Johnson-Holmquist material model (JH-2), with damage, is useful when modeling brittle materials, such as ceramics,
subjected to large pressures, shear strain and high strain rates. The model attempts to include the phenomena encountered when brittle materials are subjected to load and damage, and is one of the most widely used models when dealing with ballistic impact on ceramics. The model simulates the increase in strength shown by ceramics subjected to hydrostatic pressure as well as the reduction in strength shown by damaged ceramics. This is done by basing the model on two sets
of curves that plot the yield stress against the pressure. The first set of curves accounts for the intact material, while the second one accounts for the failed material. Each curve set depends on the plastic strain and plastic strain rate. A damage variable D accounts for the level of fracture.
The JH-2 material assumes that the material is initially elastic and isotropic and can be described by a relation of the form (summation is implied over repeated indices)
where σ i j {\displaystyle \sigma _{ij}} is a stress measure , p ( ϵ k k ) {\displaystyle p(\epsilon _{kk})} is an equation of state for the pressure, δ i j {\displaystyle \delta _{ij}} is the Kronecker delta , ϵ i j {\displaystyle \epsilon _{ij}} is a strain measure that is energy conjugate to σ i j {\displaystyle \sigma _{ij}} , and μ {\displaystyle \mu } is a shear modulus . The quantity ϵ k k {\displaystyle \epsilon _{kk}} is frequently replaced by the hydrostatic compression ξ {\displaystyle \xi } so that the equation of state is expressed as
where ρ {\displaystyle \rho } is the current mass density and ρ 0 {\displaystyle \rho _{0}} is the initial mass density.
The stress at the Hugoniot elastic limit is assumed to be given by a relation of the form
where p H E L {\displaystyle p_{\rm {HEL}}} is the pressure at the Hugoniot elastic limit and σ H E L {\displaystyle \sigma _{\rm {HEL}}} is the stress at the Hugoniot elastic limit.
The uniaxial failure strength of the intact material is assumed to be given by an equation of the form
where A , C , n {\displaystyle A,C,n} are material constants, t {\displaystyle t} is the time, ϵ p {\displaystyle \epsilon _{p}} is the inelastic strain. The inelastic strain rate is usually normalized by a reference strain rate to remove the time dependence. The reference strain rate is generally 1/s.
The quantities σ ∗ {\displaystyle \sigma ^{*}} and p ∗ {\displaystyle p^{*}} are normalized stresses and T ∗ {\displaystyle T^{*}} is a normalized tensile hydrostatic pressure, defined as
The uniaxial stress at complete fracture is assumed to be given by
where B , C , m {\displaystyle B,C,m} are material constants.
The uniaxial strength of the material at a given state of damage is then computed at a linear interpolation between the initial strength and the stress for complete failure, and is given by
The quantity D {\displaystyle D} is a scalar variable that indicates damage accumulation.
The evolution of the damage variable D {\displaystyle D} is given by
where the strain to failure ϵ f {\displaystyle \epsilon _{f}} is assumed to be
where D 1 , D 2 {\displaystyle D_{1},D_{2}} are material constants.
The function p ( ξ ) {\displaystyle p(\xi )} used in the Johnson–Holmquist material model is often called the Johnson–Holmquist equation of state and has the form
where Δ p {\displaystyle \Delta p} is an increment in the pressure and k 1 , k 2 , k 3 {\displaystyle k_{1},k_{2},k_{3}} are material constants. The increment in pressure arises from the conversion of energy loss due to damage into internal energy . Frictional effects are neglected.
The Johnson-Holmquist material model is implemented in LS-DYNA as * MAT_JOHNSON_HOLMQUIST_CERAMICS. [ 5 ]
The Johnson-Holmquist material model is implemented in the IMPETUS Afea Solver as * MAT_JH_CERAMIC.
The Johnson-Holmquist material model is implemented in Radioss Solver as /MAT/LAW79 (JOHN_HOLM) .
The Johnson-Holmquist (JH-2) material model is implemented in Abaqus as ABQ_JH2 material name . | https://en.wikipedia.org/wiki/Johnson–Holmquist_damage_model |
In mathematics, the Johnson–Lindenstrauss lemma is a result named after William B. Johnson and Joram Lindenstrauss concerning low-distortion embeddings of points from high-dimensional into low-dimensional Euclidean space . The lemma states that a set of points in a high-dimensional space can be embedded into a space of much lower dimension in such a way that distances between the points are nearly preserved . In the classical proof of the lemma, the embedding is a random orthogonal projection .
The lemma has applications in compressed sensing , manifold learning , dimensionality reduction , graph embedding , and natural language processing . Much of the data stored and manipulated on computers, including text and images, can be represented as points in a high-dimensional space (see vector space model for the case of text). However, the essential algorithms for working with such data tend to become bogged down very quickly as dimension increases. [ 1 ] It is therefore desirable to reduce the dimensionality of the data in a way that preserves its relevant structure.
Given 0 < ε < 1 {\displaystyle 0<\varepsilon <1} , a set X {\displaystyle X} of N {\displaystyle N} points in R n {\displaystyle \mathbb {R} ^{n}} , and an integer k > 8 ( ln N ) / ε 2 {\displaystyle k>8(\ln N)/\varepsilon ^{2}} , [ 2 ] there is a linear map f : R n → R k {\displaystyle f:\mathbb {R} ^{n}\rightarrow \mathbb {R} ^{k}} such that
for all u , v ∈ X {\displaystyle u,v\in X} .
The formula can be rearranged: ( 1 + ε ) − 1 ‖ f ( u ) − f ( v ) ‖ 2 ≤ ‖ u − v ‖ 2 ≤ ( 1 − ε ) − 1 ‖ f ( u ) − f ( v ) ‖ 2 {\displaystyle (1+\varepsilon )^{-1}\|f(u)-f(v)\|^{2}\leq \|u-v\|^{2}\leq (1-\varepsilon )^{-1}\|f(u)-f(v)\|^{2}}
Alternatively, for any ϵ ∈ ( 0 , 1 ) {\displaystyle \epsilon \in (0,1)} and any integer k ≥ 15 ( ln N ) / ε 2 {\displaystyle k\geq 15(\ln N)/\varepsilon ^{2}} [ Note 1 ] there exists a linear function f : R n → R k {\displaystyle f:\mathbb {R} ^{n}\rightarrow \mathbb {R} ^{k}} such that the restriction f | X {\displaystyle f|_{X}} is ( 1 + ε ) {\displaystyle (1+\varepsilon )} - bi-Lipschitz . [ Note 2 ]
Also, the lemma is tight up to a constant factor, i.e. there exists a set of points of size N that needs dimension
in order to preserve the distances between all pairs of points within a factor of ( 1 ± ε ) {\displaystyle (1\pm \varepsilon )} . [ 3 ] [ 4 ]
The classical proof of the lemma takes f {\displaystyle f} to be a scalar multiple of an orthogonal projection P {\displaystyle P} onto a random subspace of dimension k {\displaystyle k} in R n {\displaystyle \mathbb {R} ^{n}} . An orthogonal projection collapses some dimensions of the space it is applied to, which reduces the length of all vectors, as well as distance between vectors in the space. Under the conditions of the lemma, concentration of measure ensures there is a nonzero chance that a random orthogonal projection reduces pairwise distances between all points in X {\displaystyle X} by roughly a constant factor c {\displaystyle c} . Since the chance is nonzero, such projections must exist, so we can choose one P {\displaystyle P} and set f ( v ) = P v / c {\displaystyle f(v)=Pv/c} .
To obtain the projection algorithmically, it suffices with high probability to repeatedly sample orthogonal projection matrices at random. If you keep rolling the dice, you will eventually obtain one in polynomial random time.
Based on. [ 5 ]
Construct a random matrix A ∼ N ( 0 , 1 ) k × n {\displaystyle A\sim {\mathcal {N}}(0,1)^{k\times n}} , obtained by sampling each entry from the standard normal distribution. Then define P := A / k {\displaystyle P:=A/{\sqrt {k}}} . Then, for any nonzero vector x ∈ R n {\displaystyle x\in \mathbb {R} ^{n}} , let the projected vector be x ^ := P x {\displaystyle {\hat {x}}:=Px} . Standard geometric argument show that r := ‖ x ^ ‖ 2 ‖ x ‖ 2 {\displaystyle r:={\frac {\|{\hat {x}}\|^{2}}{\|x\|^{2}}}} is chi-square distributed , that is, r ∼ χ 2 ( k ) {\displaystyle r\sim \chi ^{2}(k)} . Thus, it satisfies a concentration inequality P r ( r ∈ ( 1 ± ϵ ) k ) ≥ 1 − 2 e − k 2 ( 1 2 ϵ 2 − 1 3 ϵ 3 ) {\displaystyle Pr(r\in (1\pm \epsilon )k)\geq 1-2e^{-{\frac {k}{2}}({\frac {1}{2}}\epsilon ^{2}-{\frac {1}{3}}\epsilon ^{3})}} By the union bound, the probability that this relation is true for all of x 1 , … , x N {\displaystyle x_{1},\dots ,x_{N}} is greater than 1 − 2 N e − k 2 ( 1 2 ϵ 2 − 1 3 ϵ 3 ) {\displaystyle 1-2Ne^{-{\frac {k}{2}}({\frac {1}{2}}\epsilon ^{2}-{\frac {1}{3}}\epsilon ^{3})}} .
When k ≥ 4 ln 2 N ϵ 2 ( 1 − 2 ϵ / 3 ) {\displaystyle k\geq {\frac {4\ln 2N}{\epsilon ^{2}(1-2\epsilon /3)}}} , the probability is nonzero.
More generally, when k ≥ 4 ( d + 1 ) ln 2 N ϵ 2 ( 1 − 2 ϵ / 3 ) {\displaystyle k\geq {\frac {4(d+1)\ln 2N}{\epsilon ^{2}(1-2\epsilon /3)}}} , the probability is ≥ 1 − 1 / ( 2 N ) d {\displaystyle \geq 1-1/(2N)^{d}} , allowing arbitrarily high probability of success per sample, and a fortiori polynomial random time.
A related lemma is the distributional JL lemma. This lemma states that for any 0 < ε , δ < 1 / 2 {\displaystyle 0<\varepsilon ,\delta <1/2} and positive integer d {\displaystyle d} , there exists a distribution over R k × d {\displaystyle \mathbb {R} ^{k\times d}} from which the matrix A {\displaystyle A} is drawn such that for k = O ( ε − 2 log ( 1 / δ ) ) {\displaystyle k=O(\varepsilon ^{-2}\log(1/\delta ))} and for any unit-length vector x ∈ R d {\displaystyle x\in \mathbb {R} ^{d}} , the claim below holds. [ 6 ]
One can obtain the JL lemma from the distributional version by setting x = ( u − v ) / ‖ u − v ‖ 2 {\displaystyle x=(u-v)/\|u-v\|_{2}} and δ < 1 / n 2 {\displaystyle \delta <1/n^{2}} for some pair u , v both in X . Then the JL lemma follows by a union bound over all such pairs.
(Achlioptas, 2003) [ 7 ] proposed "database-friendly" JL transform, using matrices with only entries from (-1, 0, +1).
Theorem (Achlioptas, 2003, Theorem 1.1) — Let the random k × n {\textstyle k\times n} projection matrix R {\textstyle R} have entries drawn i.i.d., either from
R i j = { + 1 with probability 1 / 2 − 1 with probability 1 / 2 {\displaystyle R_{ij}={\begin{cases}+1&{\text{ with probability }}1/2\\-1&{\text{ with probability }}1/2\end{cases}}}
or from R i j = { + 3 with probability 1 / 6 0 with probability 2 / 3 − 3 with probability 1 / 6 {\displaystyle R_{ij}={\begin{cases}+{\sqrt {3}}&{\text{ with probability }}1/6\\0&{\text{ with probability }}2/3\\-{\sqrt {3}}&{\text{ with probability }}1/6\end{cases}}}
Given a vector v {\textstyle v} , we define the random projection f ( v ) = 1 k R v {\textstyle f(v)={\frac {1}{\sqrt {k}}}Rv} . Then for any vector v ∈ R n {\textstyle v\in \mathbb {R} ^{n}} , we have − ln P r ( ‖ f ( v ) ‖ 2 2 ≥ ( 1 + ϵ ) ‖ v ‖ 2 2 ) ≥ k 2 ( ϵ 2 2 − ϵ 3 3 ) ∀ ϵ > 0 − ln P r ( ‖ f ( v ) ‖ 2 2 ≤ ( 1 − ϵ ) ‖ v ‖ 2 2 ) ≥ k 2 ( ϵ 2 2 − ϵ 3 3 ) ∀ ϵ ∈ ( 0 , 1 ) {\displaystyle {\begin{aligned}&-\ln Pr(\|f(v)\|_{2}^{2}\geq (1+\epsilon )\|v\|_{2}^{2})\geq {\frac {k}{2}}\left({\frac {\epsilon ^{2}}{2}}-{\frac {\epsilon ^{3}}{3}}\right)\quad &\forall \epsilon >0\\&-\ln Pr(\|f(v)\|_{2}^{2}\leq (1-\epsilon )\|v\|_{2}^{2})\geq {\frac {k}{2}}\left({\frac {\epsilon ^{2}}{2}}-{\frac {\epsilon ^{3}}{3}}\right)\quad &\forall \epsilon \in (0,1)\end{aligned}}}
Fix some unit vector v ∈ R n {\textstyle v\in \mathbb {R} ^{n}} . Define Q i := ∑ j R i j v j {\textstyle Q_{i}:=\sum _{j}R_{ij}v_{j}} . We have ‖ f ( v ) ‖ 2 2 = 1 k ∑ i Q i 2 {\textstyle \|f(v)\|_{2}^{2}={\frac {1}{k}}\sum _{i}Q_{i}^{2}} .
Now, since the Q 1 , … , Q k {\textstyle Q_{1},\dots ,Q_{k}} are IID, we want to apply a Chernoff concentration bound for 1 k ∑ i Q i 2 {\textstyle {\frac {1}{k}}\sum _{i}Q_{i}^{2}} around 1. This requires upper-bounding the cumulant generating function (CGF).
Moment bounds (Achlioptas, 2003, Section 6) — For any k ∈ 1 , 2 , … {\textstyle k\in 1,2,\dots } , the moment of Q i {\textstyle Q_{i}} is upper-bound by the standard gaussian Z ∼ N ( 0 , 1 ) {\textstyle Z\sim N(0,1)} : E [ Q i 2 k − 1 ] = 0 = E [ Z 2 k − 1 ] , E [ Q i 2 k ] ≤ E [ Z 2 k ] {\displaystyle E[Q_{i}^{2k-1}]=0=E[Z^{2k-1}],\quad E[Q_{i}^{2k}]\leq E[Z^{2k}]}
E [ Q i 2 k − 1 ] = 0 {\textstyle E[Q_{i}^{2k-1}]=0} is easy: just apply the fact that E [ R i j 1 … R i j l ] = 0 {\textstyle E[R_{ij_{1}}\dots R_{ij_{l}}]=0} when l {\textstyle l} is odd, since we can decompose it into a product of expectations, and one of those is the expectation of an odd power of Radamacher, which is zero.
Now, the trick is that we can rewrite Z {\textstyle Z} as Z = ∑ i Z i v i {\textstyle Z=\sum _{i}Z_{i}v_{i}} , where each Z 1 , … , Z d {\textstyle Z_{1},\dots ,Z_{d}} is a standard gaussian. Then we need to compare: E [ Q i 2 k ] = ∑ j 1 , j 2 , … , j 2 k − 1 , j 2 k E [ R i j 1 R i j 2 … R i j 2 k − 1 R i j 2 k ] v j 1 v j 2 … v j 2 k − 1 v j 2 k {\displaystyle E[Q_{i}^{2k}]=\sum _{j_{1},j_{2},\dots ,j_{2k-1},j_{2k}}E[R_{ij_{1}}R_{ij_{2}}\dots R_{ij_{2k-1}}R_{ij_{2k}}]v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}} and E [ Z 2 k ] = ∑ j 1 , j 2 , … , j 2 k − 1 , j 2 k E [ Z j 1 Z j 2 … Z j 2 k − 1 Z j 2 k ] v j 1 v j 2 … v j 2 k − 1 v j 2 k {\displaystyle E[Z^{2k}]=\sum _{j_{1},j_{2},\dots ,j_{2k-1},j_{2k}}E[Z_{j_{1}}Z_{j_{2}}\dots Z_{j_{2k-1}}Z_{j_{2k}}]v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}}
In the top sum, a term E [ R i j 1 R i j 2 … R i j 2 k − 1 R i j 2 k ] v j 1 v j 2 … v j 2 k − 1 v j 2 k {\displaystyle E[R_{ij_{1}}R_{ij_{2}}\dots R_{ij_{2k-1}}R_{ij_{2k}}]v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}} decomposes into a product of expectations, times v j 1 v j 2 … v j 2 k − 1 v j 2 k {\textstyle v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}} . The product of expectations is zero, unless the indices j 1 , j 2 , … , j 2 k {\textstyle j_{1},j_{2},\dots ,j_{2k}} are paired off. In that case, the term v j 1 v j 2 … v j 2 k − 1 v j 2 k {\textstyle v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}} is the square of something, and so v j 1 v j 2 … v j 2 k − 1 v j 2 k ≥ 0 {\displaystyle v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}\geq 0} while R i j 1 R i j 2 … R i j 2 k − 1 R i j 2 k {\textstyle R_{ij_{1}}R_{ij_{2}}\dots R_{ij_{2k-1}}R_{ij_{2k}}} is also the square of ± 1 {\textstyle \pm 1} , and so E [ R i j 1 R i j 2 … R i j 2 k − 1 R i j 2 k ] = 1 {\displaystyle E[R_{ij_{1}}R_{ij_{2}}\dots R_{ij_{2k-1}}R_{ij_{2k}}]=1}
In the bottom sum, we run a similar argument with each such term E [ Z j 1 Z j 2 … Z j 2 k − 1 Z j 2 k ] v j 1 v j 2 … v j 2 k − 1 v j 2 k {\displaystyle E[Z_{j_{1}}Z_{j_{2}}\dots Z_{j_{2k-1}}Z_{j_{2k}}]v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}} but in this case, since we have E [ Z 2 k ] = ( 2 k − 1 ) ! ! ≥ 1 {\textstyle E[Z^{2k}]=(2k-1)!!\geq 1} , we find that in each case, E [ R i j 1 R i j 2 … R i j 2 k − 1 R i j 2 k ] v j 1 v j 2 … v j 2 k − 1 v j 2 k ≤ E [ Z j 1 Z j 2 … Z j 2 k − 1 Z j 2 k ] v j 1 v j 2 … v j 2 k − 1 v j 2 k {\displaystyle E[R_{ij_{1}}R_{ij_{2}}\dots R_{ij_{2k-1}}R_{ij_{2k}}]v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}\leq E[Z_{j_{1}}Z_{j_{2}}\dots Z_{j_{2k-1}}Z_{j_{2k}}]v_{j_{1}}v_{j_{2}}\dots v_{j_{2k-1}}v_{j_{2k}}}
And so, summing all of them up, E [ Q i 2 k ] ≤ E [ Z 2 k ] {\textstyle E[Q_{i}^{2k}]\leq E[Z^{2k}]} .
The same argument works for the other case. Specifically, if R i j {\textstyle R_{ij}} is distributed like that, then E [ R i j 2 k ] = 3 k − 1 ≤ ( 2 k − 1 ) ! ! {\textstyle E[R_{ij}^{2k}]=3^{k-1}\leq (2k-1)!!} , and the proof goes through exactly the same way.
Now that Q i {\textstyle Q_{i}} is stochastically dominated by the standard gaussian, and E [ Q i 2 ] = 1 {\textstyle E[Q_{i}^{2}]=1} , it remains to perform a Chernoff bound for Q i 2 {\textstyle Q_{i}^{2}} , which requires bounding the cumulant generating function on both ends.
For any t ∈ ( 0 , 1 / 2 ) {\textstyle t\in (0,1/2)} , we can compute the cumulant generating function K Q i 2 ( t ) = ln E [ e Q i 2 t ] = ln ∑ k t k k ! E [ Q i 2 k ] ≤ ln ( 1 + ∑ k t k k ! ( 2 k − 1 ) ! ! ) = − 1 2 ln ( 1 − 2 t ) {\displaystyle {\begin{aligned}K_{Q_{i}^{2}}(t)&=\ln E[e^{Q_{i}^{2}t}]\\&=\ln \sum _{k}{\frac {t^{k}}{k!}}E[Q_{i}^{2k}]\\&\leq \ln \left(1+\sum _{k}{\frac {t^{k}}{k!}}(2k-1)!!\right)\\&=-{\frac {1}{2}}\ln(1-2t)\end{aligned}}}
Similarly, for any t ∈ ( 0 , k / 2 ) {\textstyle t\in (0,k/2)} , K 1 k ∑ i Q i 2 ( t ) = ∑ i K Q i 2 ( t / k ) ≤ − k 2 ln ( 1 − 2 t / k ) {\displaystyle K_{{\frac {1}{k}}\sum _{i}Q_{i}^{2}}(t)=\sum _{i}K_{Q_{i}^{2}}(t/k)\leq -{\frac {k}{2}}\ln(1-2t/k)}
So by the standard Chernoff bound method, for any t ∈ ( 0 , k / 2 ) {\textstyle t\in (0,k/2)} and any ϵ > 0 {\textstyle \epsilon >0} , − ln P r ( 1 k ∑ i Q i 2 ≥ 1 + ϵ ) ≥ ( 1 + ϵ ) t + k 2 ln ( 1 − 2 t / k ) {\displaystyle -\ln Pr\left({\frac {1}{k}}\sum _{i}Q_{i}^{2}\geq 1+\epsilon \right)\geq (1+\epsilon )t+{\frac {k}{2}}\ln(1-2t/k)}
The right side is maximized at t = k ϵ 2 ( 1 + ϵ ) {\textstyle t={\frac {k\epsilon }{2(1+\epsilon )}}} , at which point we have − ln P r ( 1 k ∑ i Q i 2 ≥ 1 + ϵ ) ≥ k 2 ( ϵ − ln ( 1 + ϵ ) ) ≥ k 2 ( ϵ 2 / 2 − ϵ 3 / 3 ) {\displaystyle -\ln Pr\left({\frac {1}{k}}\sum _{i}Q_{i}^{2}\geq 1+\epsilon \right)\geq {\frac {k}{2}}(\epsilon -\ln(1+\epsilon ))\geq {\frac {k}{2}}(\epsilon ^{2}/2-\epsilon ^{3}/3)}
That’s one half of the bound done. For the other half, begin with some t > 0 {\textstyle t>0} , and expand the exponential to the second order: K Q i 2 ( − t ) = ln E [ e − Q i 2 t ] ≤ ln E [ 1 − Q i 2 t + Q i 4 t 2 / 2 ] ≤ ln ( 1 − t + 3 t 2 / 2 ) {\displaystyle {\begin{aligned}K_{Q_{i}^{2}}(-t)&=\ln E[e^{-Q_{i}^{2}t}]\\&\leq \ln E[1-Q_{i}^{2}t+Q_{i}^{4}t^{2}/2]\\&\leq \ln(1-t+3t^{2}/2)\\\end{aligned}}}
K 1 k ∑ i Q i 2 ( − t ) ≤ k ln ( 1 − t / k + 3 t 2 / ( 2 k 2 ) ) {\displaystyle K_{{\frac {1}{k}}\sum _{i}Q_{i}^{2}}(-t)\leq k\ln(1-t/k+3t^{2}/(2k^{2}))}
So by the standard Chernoff bound method, for any t > 0 {\textstyle t>0} and any ϵ ∈ ( 0 , 1 ) {\textstyle \epsilon \in (0,1)} , − ln P r ( 1 k ∑ i Q i 2 ≤ 1 − ϵ ) ≥ − k [ ( 1 − ϵ ) ( t / k ) + ln ( 1 − t / k + 3 t 2 / ( 2 k 2 ) ) ] {\displaystyle -\ln Pr\left({\frac {1}{k}}\sum _{i}Q_{i}^{2}\leq 1-\epsilon \right)\geq -k[(1-\epsilon )(t/k)+\ln(1-t/k+3t^{2}/(2k^{2}))]}
Plug in t = k ϵ 2 ( 1 + ϵ ) {\textstyle t={\frac {k\epsilon }{2(1+\epsilon )}}} , and simplify, we find the right side is ≥ k ( ( ϵ − 1 ) ϵ 2 ( ϵ + 1 ) − ln ( 7 ϵ 2 + 12 ϵ + 8 8 ( ϵ + 1 ) 2 ) ) {\displaystyle \geq k\left({\frac {(\epsilon -1)\epsilon }{2(\epsilon +1)}}-\ln \left({\frac {7\epsilon ^{2}+12\epsilon +8}{8(\epsilon +1)^{2}}}\right)\right)} and expand to third Taylor power, ≥ k ( ϵ 2 / 4 − 7 ϵ 3 / 48 ) > k 2 ( ϵ 2 / 2 − ϵ 3 / 3 ) {\displaystyle \geq k(\epsilon ^{2}/4-7\epsilon ^{3}/48)>{\frac {k}{2}}(\epsilon ^{2}/2-\epsilon ^{3}/3)}
(Matoušek, 2008) [ 8 ] proposed a variant of the above JL transform that is even more sparsified, though it only works on "well-spread" vectors.
Theorem (Matoušek 2008, Theorem 4.1) — Define n ∈ N , ϵ ∈ ( 0 , 1 / 2 ) , δ ∈ ( 0 , 1 ) , α ∈ [ n − 1 / 2 , 1 ] , q ∈ [ C 0 α 2 ln ( n / ϵ δ ) , 1 ] , k ∈ [ C 1 ϵ − 2 ln 4 δ , n ] {\textstyle n\in \mathbb {N} ,\epsilon \in (0,1/2),\delta \in (0,1),\alpha \in [n^{-1/2},1],q\in [C_{0}\alpha ^{2}\ln(n/\epsilon \delta ),1],k\in [C_{1}\epsilon ^{-2}\ln {\frac {4}{\delta }},n]} , where C 0 , C 1 {\textstyle C_{0},C_{1}} are absolute constants.
Let R {\textstyle R} be a k × n {\textstyle k\times n} matrix sampled IID with
R i j = { + q − 1 / 2 with probability 1 2 q − q − 1 / 2 with probability 1 2 q 0 with probability 1 − q {\displaystyle R_{ij}={\begin{cases}+q^{-1/2}&{\text{ with probability }}{\frac {1}{2}}q\\-q^{-1/2}&{\text{ with probability }}{\frac {1}{2}}q\\0&{\text{ with probability }}1-q\end{cases}}}
Then, for any unit vector v ∈ R n {\textstyle v\in \mathbb {R} ^{n}} such that ‖ v ‖ ∞ ≤ α {\textstyle \|v\|_{\infty }\leq \alpha } , we have P r ( ‖ f ( v ) ‖ 2 2 ∈ [ 1 ± ϵ ] ) ≥ 1 − δ {\displaystyle Pr(\|f(v)\|_{2}^{2}\in [1\pm \epsilon ])\geq 1-\delta }
where f ( v ) = 1 k R v {\displaystyle f(v)={\frac {1}{\sqrt {k}}}Rv} .
The above cases are generalized to the case for matrices with independent, mean-zero, unit variance, subgaussian entries in (Dirksen, 2016). [ 9 ]
Given A , computing the matrix vector product takes O ( k d ) {\displaystyle O(kd)} time. There has been some work in deriving distributions for which the matrix vector product can be computed in less than O ( k d ) {\displaystyle O(kd)} time.
There are two major lines of work. The first, Fast Johnson Lindenstrauss Transform (FJLT), [ 10 ] was introduced by Ailon and Chazelle in 2006.
This method allows the computation of the matrix vector product in just d log d + k 2 + γ {\displaystyle d\log d+k^{2+\gamma }} for any constant γ > 0 {\displaystyle \gamma >0} .
Another approach is to build a distribution supported over matrices that are sparse. [ 11 ] This method allows keeping only an ε {\displaystyle \varepsilon } fraction of the entries in the matrix, which means the computation can be done in just k d ε {\displaystyle kd\varepsilon } time.
Furthermore, if the vector has only b {\displaystyle b} non-zero entries, the Sparse JL takes time k b ε {\displaystyle kb\varepsilon } , which may be much less than the d log d {\displaystyle d\log d} time used by Fast JL.
It is possible to combine two JL matrices by taking the so-called face-splitting product , which is defined as the tensor products of the rows (was proposed by V. Slyusar [ 12 ] in 1996 [ 13 ] [ 14 ] [ 15 ] [ 16 ] [ 17 ] for radar and digital antenna array applications).
More directly, let C ∈ R 3 × 3 {\displaystyle {C}\in \mathbb {R} ^{3\times 3}} and D ∈ R 3 × 3 {\displaystyle {D}\in \mathbb {R} ^{3\times 3}} be two matrices.
Then the face-splitting product C ∙ D {\displaystyle {C}\bullet {D}} is [ 13 ] [ 14 ] [ 15 ] [ 16 ] [ 17 ]
This idea of tensorization was used by Kasiviswanathan et al. for differential privacy . [ 18 ]
JL matrices defined like this use fewer random bits, and can be applied quickly to vectors that have tensor structure, due to the following identity: [ 15 ]
where ∘ {\displaystyle \circ } is the element-wise ( Hadamard ) product.
Such computations have been used to efficiently compute polynomial kernels and many other linear-algebra algorithms [ clarification needed ] . [ 19 ]
In 2020 [ 20 ] it was shown that if the matrices C 1 , C 2 , … , C c {\displaystyle C_{1},C_{2},\dots ,C_{c}} are independent ± 1 {\displaystyle \pm 1} or Gaussian matrices, the combined matrix C 1 ∙ ⋯ ∙ C c {\displaystyle C_{1}\bullet \dots \bullet C_{c}} satisfies the distributional JL lemma if the number of rows is at least
For large ϵ {\displaystyle \epsilon } this is as good as the completely random Johnson-Lindenstrauss, but
a matching lower bound in the same paper shows that this exponential dependency on ( log 1 / δ ) c {\displaystyle (\log 1/\delta )^{c}} is necessary.
Alternative JL constructions are suggested to circumvent this. | https://en.wikipedia.org/wiki/Johnson–Lindenstrauss_lemma |
Johnson–Nyquist noise ( thermal noise , Johnson noise , or Nyquist noise ) is the electronic noise generated by the thermal agitation of the charge carriers (usually the electrons ) inside an electrical conductor at equilibrium, which happens regardless of any applied voltage . Thermal noise is present in all electrical circuits , and in sensitive electronic equipment (such as radio receivers ) can drown out weak signals, and can be the limiting factor on sensitivity of electrical measuring instruments. Thermal noise is proportional to absolute temperature , so some sensitive electronic equipment such as radio telescope receivers are cooled to cryogenic temperatures to improve their signal-to-noise ratio . The generic, statistical physical derivation of this noise is called the fluctuation-dissipation theorem , where generalized impedance or generalized susceptibility is used to characterize the medium.
Thermal noise in an ideal resistor is approximately white , meaning that its power spectral density is nearly constant throughout the frequency spectrum (Figure 2). When limited to a finite bandwidth and viewed in the time domain (as sketched in Figure 1), thermal noise has a nearly Gaussian amplitude distribution . [ 1 ]
For the general case, this definition applies to charge carriers in any type of conducting medium (e.g. ions in an electrolyte ), not just resistors . Thermal noise is distinct from shot noise , which consists of additional current fluctuations that occur when a voltage is applied and a macroscopic current starts to flow.
In 1905, in one of Albert Einstein 's Annus mirabilis papers the theory of Brownian motion was first solved in terms of thermal fluctuations. The following year, in a second paper about Brownian motion, Einstein suggested that the same phenomena could be applied to derive thermally-agitated currents, but did not carry out the calculation as he considered it to be untestable. [ 2 ]
Geertruida de Haas-Lorentz , daughter of Hendrik Lorentz , in her doctoral thesis of 1912, expanded on Einstein stochastic theory and first applied it to the study of electrons, deriving a formula for the mean-squared value of the thermal current. [ 2 ] [ 3 ]
Walter H. Schottky studied the problem in 1918, while studying thermal noise using Einstein's theories, experimentally discovered another kind of noise, the shot noise . [ 2 ]
Frits Zernike working in electrical metrology, found unusual random deflections while working with high-sensitive galvanometers . He rejected the idea that the noise was mechanical, and concluded that it was of thermal nature. In 1927, he introduced the idea of autocorrelations to electrical measurements and calculated the time detection limit. His work coincided with De Haas-Lorentz' prediction. [ 2 ]
The same year, working independently without any knowledge of Zernike's work, John B. Johnson working in Bell Labs found the same kind of noise in communication systems, but described it in terms of frequencies. [ 4 ] [ 5 ] [ 2 ] He described his findings to Harry Nyquist , also at Bell Labs, who used principles of thermodynamics and statistical mechanics to explain the results, published in 1928. [ 6 ]
Johnson's experiment (Figure 1) found that the thermal noise from a resistance R {\displaystyle R} at kelvin temperature T {\displaystyle T} and bandlimited to a frequency band of bandwidth Δ f {\displaystyle \Delta f} (Figure 3) has a mean square voltage of: [ 5 ]
where k B {\displaystyle k_{\rm {B}}} is the Boltzmann constant ( 1.380 649 × 10 −23 joules per kelvin ). While this equation applies to ideal resistors (i.e. pure resistances without any frequency-dependence) at non-extreme frequency and temperatures, a more accurate general form accounts for complex impedances and quantum effects. Conventional electronics generally operate over a more limited bandwidth , so Johnson's equation is often satisfactory.
The mean square voltage per hertz of bandwidth is 4 k B T R {\displaystyle 4k_{\text{B}}TR} and may be called the power spectral density (Figure 2). [ note 1 ] Its square root at room temperature (around 300 K) approximates to 0.13 R {\displaystyle {\sqrt {R}}} in units of nanovolts / √ hertz . A 10 kΩ resistor, for example, would have approximately 13 nanovolts / √ hertz at room temperature.
The square root of the mean square voltage yields the root mean square (RMS) voltage observed over the bandwidth Δ f {\displaystyle \Delta f} :
A resistor with thermal noise can be represented by its Thévenin equivalent circuit (Figure 4B) consisting of a noiseless resistor in series with a gaussian noise voltage source with the above RMS voltage.
Around room temperature, 3 kΩ provides almost one microvolt of RMS noise over 20 kHz (the human hearing range ) and 60 Ω·Hz for R Δ f {\displaystyle R\,\Delta f} corresponds to almost one nanovolt of RMS noise.
A resistor with thermal noise can also be converted into its Norton equivalent circuit (Figure 4C) consisting of a noise-free resistor in parallel with a gaussian noise current source with the following RMS current:
Ideal capacitors , as lossless devices, do not have thermal noise. However, the combination of a resistor and a capacitor (an RC circuit , a common low-pass filter ) has what is called kTC noise. The noise bandwidth of an RC circuit is Δ f = 1 4 R C . {\displaystyle \Delta f{=}{\tfrac {1}{4RC}}.} [ 7 ] When this is substituted into the thermal noise equation, the result has an unusually simple form as the value of the resistance ( R ) drops out of the equation. This is because higher R decreases the bandwidth as much as it increases the noise.
The mean-square and RMS noise voltage generated in such a filter are: [ 8 ]
The noise charge Q n {\displaystyle Q_{n}} is the capacitance times the voltage:
This charge noise is the origin of the term " kTC noise". Although independent of the resistor's value, 100% of the kTC noise arises in the resistor. Therefore, it would incorrect to double-count both a resistor's thermal noise and its associated kTC noise, [ 7 ] and the temperature of the resistor alone should be used, even if the resistor and the capacitor are at different temperatures. Some values are tabulated below:
An extreme case is the zero bandwidth limit called the reset noise left on a capacitor by opening an ideal switch . Though an ideal switch's open resistance is infinite, the formula still applies. However, now the RMS voltage must be interpreted not as a time average, but as an average over many such reset events, since the voltage is constant when the bandwidth is zero. In this sense, the Johnson noise of an RC circuit can be seen to be inherent, an effect of the thermodynamic distribution of the number of electrons on the capacitor, even without the involvement of a resistor.
The noise is not caused by the capacitor itself, but by the thermodynamic fluctuations of the amount of charge on the capacitor. Once the capacitor is disconnected from a conducting circuit, the thermodynamic fluctuation is frozen at a random value with standard deviation as given above. The reset noise of capacitive sensors is often a limiting noise source, for example in image sensors .
Any system in thermal equilibrium has state variables with a mean energy of kT / 2 per degree of freedom . Using the formula for energy on a capacitor ( E = 1 / 2 CV 2 ), mean noise energy on a capacitor can be seen to also be 1 / 2 C kT / C = kT / 2 . Thermal noise on a capacitor can be derived from this relationship, without consideration of resistance.
The Johnson–Nyquist noise has applications in precision measurements, in which it is typically called "Johnson noise thermometry". [ 9 ]
For example, the NIST in 2017 used the Johnson noise thermometry to measure the Boltzmann constant with uncertainty less than 3 ppm . It accomplished this by using Josephson voltage standard and a quantum Hall resistor , held at the triple-point temperature of water . The voltage is measured over a period of 100 days and integrated. [ 10 ]
This was done in 2017, when the triple point of water's temperature was 273.16 K by definition, and the Boltzmann constant was experimentally measurable. Because the acoustic gas thermometry reached 0.2 ppm in uncertainty, and Johnson noise 2.8 ppm, this fulfilled the preconditions for a redefinition. After the 2019 redefinition , the kelvin was defined so that the Boltzmann constant is 1.380649×10 −23 J⋅K −1 , and the triple point of water became experimentally measurable. [ 11 ] [ 12 ] [ 13 ]
Inductors are the dual of capacitors. Analogous to kTC noise, a resistor with an inductor L {\displaystyle L} results in a noise current that is independent of resistance: [ 14 ]
The noise generated at a resistor R S {\displaystyle R_{\text{S}}} can transfer to the remaining circuit. The maximum power transfer happens when the Thévenin equivalent resistance R L {\displaystyle R_{\rm {L}}} of the remaining circuit matches R S {\displaystyle R_{\text{S}}} . [ 14 ] In this case, each of the two resistors dissipates noise in both itself and in the other resistor. Since only half of the source voltage drops across any one of these resistors, this maximum noise power transfer is:
This maximum is independent of the resistance and is called the available noise power from a resistor. [ 14 ]
Signal power is often measured in dBm ( decibels relative to 1 milliwatt ). Available noise power would thus be 10 log 10 ( k B T Δ f 1 mW ) {\displaystyle 10\ \log _{10}({\tfrac {k_{\text{B}}T\Delta f}{\text{1 mW}}})} in dBm. At room temperature (300 K), the available noise power can be easily approximated as 10 log 10 ( Δ f ) − 173.8 {\displaystyle 10\ \log _{10}(\Delta f)-173.8} in dBm for a bandwidth in hertz. [ 14 ] [ 15 ] : 260 Some example available noise power in dBm are tabulated below:
Nyquist's 1928 paper "Thermal Agitation of Electric Charge in Conductors" [ 6 ] used concepts about potential energy and harmonic oscillators from the equipartition law of Boltzmann and Maxwell [ 16 ] to explain Johnson's experimental result. Nyquist's thought experiment summed the energy contribution of each standing wave mode of oscillation on a long lossless transmission line between two equal resistors ( R 1 = R 2 {\displaystyle R_{1}{=}R_{2}} ). According to the conclusion of Figure 5, the total average power transferred over bandwidth Δ f {\displaystyle \Delta f} from R 1 {\displaystyle R_{1}} and absorbed by R 2 {\displaystyle R_{2}} was determined to be:
Simple application of Ohm's law says the current from V 1 {\displaystyle V_{1}} (the thermal voltage noise of only R 1 {\displaystyle R_{1}} ) through the combined resistance is I 1 = V 1 R 1 + R 2 = V 1 2 R 1 {\textstyle I_{1}{=}{\tfrac {V_{1}}{R_{1}+R_{2}}}{=}{\tfrac {V_{1}}{2R_{1}}}} , so the power transferred from R 1 {\displaystyle R_{1}} to R 2 {\displaystyle R_{2}} is the square of this current multiplied by R 2 {\displaystyle R_{2}} , which simplifies to: [ 6 ]
Setting this P 1 {\textstyle P_{\text{1}}} equal to the earlier average power expression P 1 ¯ {\textstyle {\overline {P_{1}}}} allows solving for the average of V 1 2 {\textstyle V_{1}^{2}} over that bandwidth:
Nyquist used similar reasoning to provide a generalized expression that applies to non-equal and complex impedances too. And while Nyquist above used k B T {\displaystyle k_{\rm {B}}T} according to classical theory, Nyquist concluded his paper by attempting to use a more involved expression that incorporated the Planck constant h {\displaystyle h} (from the new theory of quantum mechanics ). [ 6 ]
The 4 k B T R {\displaystyle 4k_{\text{B}}TR} voltage noise described above is a special case for a purely resistive component for low to moderate frequencies. In general, the thermal electrical noise continues to be related to resistive response in many more generalized electrical cases, as a consequence of the fluctuation-dissipation theorem . Below a variety of generalizations are noted. All of these generalizations share a common limitation, that they only apply in cases where the electrical component under consideration is purely passive and linear.
Nyquist's original paper also provided the generalized noise for components having partly reactive response, e.g., sources that contain capacitors or inductors. [ 6 ] Such a component can be described by a frequency-dependent complex electrical impedance Z ( f ) {\displaystyle Z(f)} . The formula for the power spectral density of the series noise voltage is
The function η ( f ) {\displaystyle \eta (f)} is approximately 1, except at very high frequencies or near absolute zero (see below).
The real part of impedance, Re [ Z ( f ) ] {\displaystyle \operatorname {Re} [Z(f)]} , is in general frequency dependent and so the Johnson–Nyquist noise is not white noise. The RMS noise voltage over a span of frequencies f 1 {\displaystyle f_{1}} to f 2 {\displaystyle f_{2}} can be found by taking the square root of integration of the power spectral density:
Alternatively, a parallel noise current can be used to describe Johnson noise, its power spectral density being
where Y ( f ) = 1 Z ( f ) {\displaystyle Y(f){=}{\tfrac {1}{Z(f)}}} is the electrical admittance ; note that Re [ Y ( f ) ] = Re [ Z ( f ) ] | Z ( f ) | 2 . {\displaystyle \operatorname {Re} [Y(f)]{=}{\tfrac {\operatorname {Re} [Z(f)]}{|Z(f)|^{2}}}\,.}
With proper consideration of quantum effects (which are relevant for very high frequencies or very low temperatures near absolute zero ), the multiplying factor η ( f ) {\displaystyle \eta (f)} mentioned earlier is in general given by: [ 17 ]
At very high frequencies ( f ≳ k B T h {\displaystyle f\gtrsim {\tfrac {k_{\text{B}}T}{h}}} ), the spectral density S v n v n ( f ) {\displaystyle S_{v_{n}v_{n}}(f)} now starts to exponentially decrease to zero. At room temperature this transition occurs in the terahertz, far beyond the capabilities of conventional electronics, and so it is valid to set η ( f ) = 1 {\displaystyle \eta (f)=1} for conventional electronics work.
Nyquist's formula is essentially the same as that derived by Planck in 1901 for electromagnetic radiation of a blackbody in one dimension—i.e., it is the one-dimensional version of Planck's law of blackbody radiation . [ 18 ] In other words, a hot resistor will create electromagnetic waves on a transmission line just as a hot object will create electromagnetic waves in free space.
In 1946, Robert H. Dicke elaborated on the relationship, [ 19 ] and further connected it to properties of antennas, particularly the fact that the average antenna aperture over all different directions cannot be larger than λ 2 4 π {\displaystyle {\tfrac {\lambda ^{2}}{4\pi }}} , where λ is wavelength. This comes from the different frequency dependence of 3D versus 1D Planck's law.
Richard Q. Twiss extended Nyquist's formulas to multi- port passive electrical networks, including non-reciprocal devices such as circulators and isolators . [ 20 ] Thermal noise appears at every port, and can be described as random series voltage sources in series with each port. The random voltages at different ports may be correlated, and their amplitudes and correlations are fully described by a set of cross-spectral density functions relating the different noise voltages,
where the Z m n {\displaystyle Z_{mn}} are the elements of the impedance matrix Z {\displaystyle \mathbf {Z} } .
Again, an alternative description of the noise is instead in terms of parallel current sources applied at each port. Their cross-spectral density is given by
where Y = Z − 1 {\displaystyle \mathbf {Y} =\mathbf {Z} ^{-1}} is the admittance matrix .
This article incorporates public domain material from Federal Standard 1037C . General Services Administration . Archived from the original on 2022-01-22. (in support of MIL-STD-188 ). | https://en.wikipedia.org/wiki/Johnson–Nyquist_noise |
The joining technology is used in any type of mechanical joint which is the arrangement formed by two or more elements: typically, two physical parts and a joining element. The mechanical joining systems make possible to form a set of several pieces using the individual parts and the corresponding joining elements. There are fixed sets and removable sets.
Most common utensils (tools, furniture, weapons, clothing, footwear, vehicles, ...) are made up of sets of parts. [ 1 ] The study of mechanical joints is essential to ensure the proper functioning of the mentioned assemblies.”. [ 2 ]
The joints between pieces of wood (natural or processed), between materials similar to joint effects (for example, plastic foam boards) and combined materials can be various. If the parts to be joined include (in addition to wood) metals, ceramic materials or polymers, the joints can be more elaborate.
Joints of two pieces of wood . A mortise determines the shape of the ends of the two pieces of wood to be joined. Some of traditional joints are listed below:
Often the handle is wedged and forced. Sometimes with a skinny type bailer or similar.
Some manufactured items are made from a raw material using self unions, that is: unions without using other joining materials.
The replacement of cut stone tools by polished stone tools is not the most important innovation, although it is the one that gives the period its name. The diversification of tasks that needed to be done (cutting down trees, sowing seeds, harvesting cereals, much of the grain...) explains that the first farmers had to create new specific tools for each function. Most utensils were made of flint with a wooden handle, others were made of bone and animal horn. They made pottery to store food, fabric for clothing with wool and linen, musical instruments...
The mortice and tenon coupling was used to join the planks of the ancient Greek ships with double box and false wick. This set was fixed with a wooden peg on each side. [ 17 ] The construction system of the large ships of antiquity (the chaining with a guarantor of the lining plates) was of Phoenician origin. The Romans called it "Phoenician chains" ("coagmenta punicana", in Latin plural). [ 18 ]
The mortice and tenon coupling was used to join the planks of the ancient Greek ships with double box and false wick. This set was fixed with a wooden peg on each side. The construction system of the large ships of antiquity (the chaining with a guarantor of the lining plates) was of Phoenician origin. The Romans called it " Phoenician joints " ("coagmenta punicana", in Latin plural). [ 18 ]
The images show three material assemblies representing three mechanical joints and the corresponding joint elements. The first example, a solar boat, recalls the sewn joints of the wooden pieces that make up the boat's hull. In this particular case the joints were reinforced with box and wick fittings. The second example is that of the wheels of a war chariot. The button of a wheel was formed by the union of the six "vertices" of six pieces of wood - each bent at an angle - so that each spoke was formed by the union of two arms of contiguous angular pieces. The third example is based on the funerary mask of Tutankhamun and shows a kind of soft welding for metals.
Classical Greek culture offers many examples of ensembles made up of pieces mechanically joined together. The following sets are randomly presented: a hoplite spear, a hoplite shield, a mechanical system for chariot racing, [ 19 ] the Antikythera mechanism , and general war machines. [ 20 ]
In figure 1 you can see a Greek spear made up of three parts: the tip (of bronze or steel), the shaft (of ash or a similar wood) and the shaft (of bronze or steel). This set involves two unions.
The ships of the Vikings, the drakkars, had (almost all) tingled hulls.
The juxtaposed lath system was the most popular on the Mediterranean coast. Boats, oxen, gussies and ships of great harbor had ships according to this arrangement. The tingled can method (in which each can overlaps the bottom can) was typical of the Atlantic coasts. An example would be the ships of the Vikings, the drakkars. The method of sewing the tins was followed in various parts of the world, with examples in the Nordic countries and on the coasts of the Indian Ocean.
The union of two planks in a drakkar was secured by means of iron rivets (or nails with a dome on the outside and a bent point on the inside). The tightness was obtained with moss or wool impregnated with resin or glue.
Since about the fifteenth century, joining technologies have been the subject of patents and similar actions. Here follows a small, random sample, arranged chronologically. The listed patents include assembly tools for mounting or tightening fasteners. | https://en.wikipedia.org/wiki/Joining_technology |
A building joint is a junction where building elements meet without applying a static load from one element to another. When one or more of these vertical or horizontal elements that meet are required by the local building code to have a fire-resistance rating , the resulting opening that makes up the joint must be firestopped in order to restore the required compartmentalisation .
Such joints are often subject to movement. Firestops must be able to demonstrate the ability to withstand operational movement prior to fire testing . Firestops for such building joints can be qualified to UL 2079 -- Tests for Fire Resistance of Building Joint Systems .
The joint design must consider the anticipated operational movement of each joint. Timing is also important, as freshly poured concrete shrinks [ 1 ] particularly during the first few months of a new building, potentially causing joint size changes.
Where vertical fire-resistance rated wall assemblies meet the underside of the floor slab above, a movement joint results, which can be subject to compression, as the freshly placed concrete cures and shrinks all over a new building. This joint must be firestopped in a flexible manner. | https://en.wikipedia.org/wiki/Joint_(building) |
The Joint CMU-Pitt Ph.D Program in Computational Biology (CPCB) is an interdisciplinary graduate training program in computational biology . It is a joint program between Carnegie Mellon University and the University of Pittsburgh in Pittsburgh , Pennsylvania.
The Department of Computational Biology (DCB) at the University of Pittsburgh and the Computational Biology Department at Carnegie Mellon University together serve as the administrative homes of the CPCB. Dr. Ivet Bahar , the John K. Vries Chair of the Department of Computational Biology at Pitt, and Dr. Robert F. Murphy , Director of the Computational Biology Department at Carnegie Mellon, are the founding directors of the CPCB.
In 2009, the CPCB was selected as one of ten programs nationwide to receive an NIH T32 Training Grant as part of the NIBIB-HHMI Interfaces Program (award T32-EB009403). [ 1 ] | https://en.wikipedia.org/wiki/Joint_CMU-Pitt_Ph.D._Program_in_Computational_Biology |
The Joint Center for Artificial Photosynthesis ( JCAP ), founded in 2010, is a (DOE) Energy Innovation Hub whose primary mission is to find a cost-effective method to produce fuels using only sunlight, water, and carbon-dioxide. The program has a budget of $122M over five years, subject to Congressional appropriation. [ 1 ] [ 2 ] [ 3 ] [ 4 ]
The Director of JCAP is Professor Harry Atwater of Caltech and its two main centers are located at the California Institute of Technology and the Lawrence Berkeley National Laboratory . In addition, JCAP has partners from Stanford University , the University of California at Berkeley , University of California at Santa Barbara , University of California at Irvine , the University of California at San Diego , and Stanford Linear Accelerator . In addition, JCAP also serves as a hub for other solar fuels research teams across the United States, including 20 DOE Energy Frontier Research Center.
In Obama's 2011 State of the Union address , he mentioned the Joint Center for Artificial Photosynthesis. Specifically, he said, "We're issuing a challenge. We're telling America's scientists and engineers that if they assemble teams of the best minds in their fields, and focus on the hardest problems in clean energy, we'll fund the Apollo projects of our time. At the California Institute of Technology , they're developing a way to turn sunlight and water into fuel for our cars". [ 5 ] [ 6 ] [ 7 ] | https://en.wikipedia.org/wiki/Joint_Center_for_Artificial_Photosynthesis |
The Joint Committee on Structural Safety ( JCSS ) is an international scientific and technical association concerned with research , development and best practice in structural reliability in civil engineering . This includes methods for calculating the reliability of structures , but also the discussion and development of recommendations on acceptable reliability (how safe is safe enough).
The JCSS also deals with risk-based and risk-informed decision making for engineering systems. The JCSS is a voluntary organisation that aims to establish the foundations and benefits of probabilistic methods in engineering practice.
The JCSS has met twice a year since 1971 and coordinates and presents the work done. The JCSS regularly organises workshops to promote and facilitate professional exchange and regularly offers courses. [ 1 ]
The Joint Committee on Structural Safety (JCSS) is an international body established in 1971 by the Liaison Committee of International Associations of Civil Engineering (Liaison Committee), [ 2 ] i.e.
to improve the general knowledge of structural reliability and technical risk assessments among engineers and to coordinate the activities of civil engineering associations in the field of structural reliability. [ 3 ]
In the initial phase of the JCSS, the focus was particularly on pre-normative research and development in the field of structural reliability theory and risk analysis. Basic principles were discussed and developed to accompany the development of the first generation of European structural design standards, the EUROCODES , the development of which was decided by the European Union in 1975. The introduction of the Eurocodes meant a paradigm shift in building standards, from the concept of allowable stresses to the concept of partial safety factors . This paradigm shift required broad coordination in the scientific-technical field and the international professional associations in the construction industry.
In the course of the application of the EUROCODES , probabilistic methods were also increasingly used in practice in the field of civil engineering for new and existing structures, which resulted in questions and challenges for research. In the course of this, the JCSS has repeatedly founded task groups for new topics, some of which have manifested themselves as permanent working groups.
The work of the JCSS has found its way into various standards, e.g. in EUROCODES , [ 4 ] ISO 2394. [ 5 ]
Currently, the JCSS organises its activities into 3 working groups, WP1 "The Probabilistic Model Code", WP2 "Risk-Informed Decision Support for Systems Involving Structures", WP3 "The JCSS Continuing Education and Advanced School" and a task group TG1 "The JCSS Special Task Force on Resilience and Sustainability in the Built Environment".
This working group is concerned with updating and further developing the main publication of the JCSS, the Probabilistic Model Code (PMC). The PMC provides a basis for reliability-based design of structures. Principles, methods and models are compiled. The target audience for the PMC are standard developers as well as engineers who want to apply reliability-based methods in practice.
This working group deals with risk analysis of technical systems and addresses the issues of modelling consequences, modelling and formulation of acceptance criteria with best practice in the field of risk analysis and analyses problems with existing and applied procedures for risk identification. Furthermore, this working group deals with risk perception, risk communication and risk acceptance criteria (see also ALARP ).
This working group deals with knowledge transfer in all its facets. This includes sharing the experiences of the members of the JCSS and other experts and initiating workshops. In addition, this working group also organises courses worldwide. The target group of these courses are professionals from industry and authorities as well as students who want to learn about the use of probabilistic methods in civil engineering and develop their skills in this field.
This special working group, which was founded in 2017, aims to formulate the responsibility of civil engineers with regard to sustainable and resilient development and to make a positive contribution to a better future handling of resources in the built environment. In the process, methods for assessing the sustainability and resilience of structural design are to be identified. In 2020, the publication of the " Global Consensus on Sustainability in the Built Environment ", [ 6 ] was a significant first output of this special working group.
The JCSS is led by the President, who is responsible for the organisation of the JCSS and is the general interface with the Liaison Committee. The JCSS can propose new task and working groups. The establishment of new task groups requires the approval of the Liaison Committee. Meetings of the Board are held twice a year in conjunction with the general JCSS meetings. Membership in the JCSS is by invitation only through the JCSS Board of Directors.
The President shall be elected by the Board for a period of 5 years and may be re-elected without term limits. The designation of the representatives of the sector Associations on the Board shall be the responsibility of the sector Associations.
Presidents:
The Board is composed of representatives of the Liaison Committee and the reporters of the individual working groups.
Currently the board of the JCSS is composed as follows: | https://en.wikipedia.org/wiki/Joint_Committee_on_Structural_Safety |
The Joint Dark Energy Mission ( JDEM ) was an Einstein probe that planned to focus on investigating dark energy . JDEM was a partnership between NASA and the U.S. Department of Energy (DOE).
In August 2010, the Board on Physics and Astronomy of the National Science Foundation (NSF) recommended the Wide Field Infrared Survey Telescope (WFIRST) mission, a renamed JDEM-Omega proposal which has superseded SNAP, Destiny, and Advanced Dark Energy Physics Telescope (ADEPT), as the highest priority for development in the decade around 2020. This would be a 1.5-meter telescope with a 144-megapixel HgCdTe focal plane array, located at the Sun-Earth L2 Lagrange point . The expected cost is around US$1.6 billion.
The Dark Energy Space Telescope (Destiny), was a planned project by NASA and DOE , designed to perform precision measurements of the universe to provide an understanding of dark energy . The space telescope will derive the expansion of the universe by measuring up to 3,000 distant supernovae each year of its three-year mission lifetime, and will additionally study the structure of matter in the universe by measuring millions of galaxies in a weak gravitational lensing survey. The Destiny spacecraft features an optical telescope with a 1.8 metre primary mirror. The telescope images infrared light onto an array of solid-state detectors. The mission is designed to be deployed in a halo orbit about the Sun-Earth L 2 Lagrange point . [ 1 ]
The Destiny proposal has been superseded by the Wide Field Infrared Survey Telescope (WFIRST).
The SuperNova Acceleration Probe (SNAP) mission [ 2 ] was proposed to provide an understanding of the mechanism driving the acceleration of the universe and determine the nature of dark energy. To achieve these goals, the spacecraft needed to be able to detect these supernova when they are at their brightest moment. [ 3 ] The mission was proposed as an experiment for the JDEM. [ 2 ] The satellite observatory would be capable of measuring up to 2,000 distant supernovae each year of its three-year mission lifetime. SNAP was also planned to observe the small distortions of light from distant galaxies to reveal more about the expansion history of the universe. [ 4 ] SNAP was initially planned to launch in 2013.
To understand what is driving the acceleration of the universe, scientists need to see greater redshifts from supernovas than what is seen from Earth. The SNAP would detect redshifts of 1.7 from distant supernovas up to 10 billion light years away. At this distance, the acceleration of the universe is easily seen. To measure the presence of dark energy, a process called weak lensing can be used. [ 5 ]
The SNAP would have used an optical setup called the three-mirror anastigmat . This consists of a main mirror with a diameter of 2 meters to take in light. It reflects this light to a second mirror. Then this light is transferred to two additional smaller mirrors which direct the light to the spacecraft's instruments. It will also contain 72 different cameras. 36 of them are able to detect visible light and the other 36 detect infrared light . Its cameras combined produces the equivalence of a 600 megapixel camera. The resolution of the camera is about 0.2 arcseconds in the visible spectrum and 0.3 arcseconds in the infrared spectrum. The SNAP would also have a spectrograph attached to it. The purpose of it is to detect what type of supernova SNAP is observing, determine the redshift, detect changes between different supernovas, and store supernova spectra for future reference. [ 6 ]
JDEM recognized several potential problems of the SNAP project:
The SNAP proposal has been superseded by the Wide Field Infrared Survey Telescope (WFIRST). | https://en.wikipedia.org/wiki/Joint_Dark_Energy_Mission |
The Joint Electronics Type Designation System (JETDS) , which was previously known as the Joint Army-Navy Nomenclature System (AN System. JAN) and the Joint Communications-Electronics Nomenclature System , is a method developed by the U.S. War Department during World War II for assigning an unclassified designator to electronic equipment. In 1957, the JETDS was formalized in MIL-STD-196 .
Computer software and commercial unmodified electronics for which the manufacturer maintains design control are not covered.
Electronic material, from a military point of view, generally includes those electronic devices employed in data processing, detection and tracking (underwater, sea, land-based, air and space), recognition and identification, communications, aids to navigation, weapons control and evaluation, flight control, and electronics countermeasures. The JETDS applies to equipment throughout the DoD and select NATO allies today. [ 1 ] Nomenclature is assigned to:
This system is separate from the "M" designation used in the Army Nomenclature System (MIL-STD-1464A).
Items are given an Item Level which describes their hierarchy
The core of the JETDS system is the combination of a Type Designation with an Item Name to specify a particular item.
For example:
The type designation is a unique series of letters and numbers which specifies an item. There are three basic forms of type designator used:
The Type Designation is used in conjunction with an approved Item Name drawn from the H-6 Item Name Directory.
For example:
The type designation used to specify Systems, Subsystems, Centers, Central, and Sets is made up of a prefix AN/ , three type designation indicator letters, a hyphen, and a type designation number. The AN prefix signifies Army-Navy. The three type designation letters (chosen from the table below) specify where the equipment is used, what the equipment is, and what its purpose is. The type designation number helps specify the exact item; subsequent items with the same Installation/Type/Purpose are numbered sequentially (i.e. the next item developed after the AN/PRC-34 would be the AN/PRC-35).
For example:
* Additional info on Installation indicators:
** Additional info on Type of Equipment indicators:
The type designation used to specify Groups (assemblies that are used in conjunction with others to function) is made up of a two letter group indicator (from the table below), followed by a dash, a group number, followed by a slash, and 1-3 letters specifying the equipment it is "part of" or "used with" (see Table 1). If the group is unique and only "part of" or "used with" one particular equipment, that equipment may be specified. If the group may be used with multiple different items, then it is more appropriate to designate it more generally.
For example:
The type designation used to specify Units is made up of a unit letter(s) indicator (from the table below), followed by a dash, a unit number, followed by a slash, and 1-3 letters specifying the equipment it is part of or used with (see Table 1). As with Group type designations, if the Unit is unique and is "part of" or "used with" only one particular equipment, that equipment may be specified. If the unit is used with multiple different items, the equipment designation should include only the indicators which are common or appropriate. If a unit could be described by multiple indicators, the indicator which best describes the unit's primary function should be used. The exception would be if there exists a unit indicator which can describe the unit's multiple functions (see examples below); if such a multi-function describing unit indicator exists, then it should be used.
For example:
A modification letter is placed after the type designation number to signify a modification to a specific equipment that still retains at least one-way interchangeability with all previous versions. Modification letters begin with "A" and proceed sequentially. For more information on Interchangeability (see below).
Note: the letters "I", "O", "Q", "S", "T", "X", "Y", and "Z" are not to be used as modification letters
For example:
A suffix "(V)" following the type designation number and any modification letters indicates variable components or configurations for said Group/Set/Subsystem/System/Center/Central. A number may follow the parenthetical V to identify a specific configuration.
For example:
Note: A specific equipment should only be given a (V) signifier if it can be configured with different components, not simply because one of its components has a (V) signifier. The (V) signifier would be warranted if the item accepted variable configurations of a particular component.
For example:
A suffix of "(P)" following the type designation number and any modification letters indicates a Unit which is designed to accept "plug-in" modules capable of changing the function, frequency, or other technical characteristics of the unit. The plug-in is not considered part of the unit itself.
For example:
A suffix of "(C)" following the type designation number and any modification letters indicates an item which directly contains NSA-controlled cryptographic material.
For example:
A suffix of "-T n ", where n is a number, indicates equipment (Set, Subsystem, System, Center, or Central) designed to provide training in the operation of a specific set or multiple sets. If it is designed specifically to provide training for one particular unit, then that unit may be specified. If it is a training equipment which can provide practice for various different sets/subsystems/systems etc., then that should be indicated with the appropriate letter indicators.
For example:
For example:
A digit or digits in parentheses following the type designation letters indicates the type of ADPE included in the item.
For example:
Maintenance equipment that is given a type designation is set up as AN/xxM, where the first two letters after the slash (signifying Installation and Type of equipment) are followed by an M.
However, if a maintenance or test Unit or Group is considered a "part of" the item in question, it does not receive the M signifier.
For example:
A change in the power input voltage, phase, or frequency is denoted by addition of the letter(s) "X", "Y", or "Z". The first such modification would be denoted with an "X", the second with a "Y", the third with a "Z", the fourth with an "XX", etc. If simultaneous modifications are made that improve the equipment as well as affect power input, then both a modification letter (A, B, C, D, etc.) as well as a power requirement modification letter (X, Y, Z, etc.) will be used.
For example:
A pair of parentheses surrounding where the type designation number would be located is used to signify an experimental or developmental model. Type designation number is not required but is useful for clarity. When the developmental model is ready for production, the parentheses are struck off.
For example:
Electronic type (non-rotating) servo amplifiers are designated "AM"; rotating type servo amplifiers are designated "PU".
Plug-in Units which can be described by their function (like receiver, microphone, loudspeaker, etc.) will use those corresponding Unit indicators. If no indicator exists to describe the plug-in's function, then the generic plug-in unit indicator (PL) will be used.
For example:
Type designators for groups and units like cables, waveguides, cords, etc. may also include a parenthetical "( -FT, -IN)" to designate the specified length. These type designators will not include a specified System/Subsystem/Center/Central/Set type designator after the / but will be given a more generic indicator like /U or /GR. However, a group or unit type designation that is already linked to a specific system/subsystem/center/central/set may use ( -FT, -IN) if the system/subsystem/center/central/set uses multiple of the group/unit and they are only distinguishable by length. This use is only for new assignments and will not be retroactive
For example:
Primary batteries (non-rechargeable) are designated using "BA"; Secondary type batteries (rechargeable) are designated using "BB".
JETDS was adopted 16 February 1943 by the Joint Communications Board for all new Army and Navy airborne, radio, and radar equipment. [ 2 ] Over time it was extended to cover the Marine Corps and the Navy's ship, submarine, amphibious, and ground electronic equipment. When the Air Force was established as a separate department, it continued the use of the system for electronic equipment. JETDS was adopted by the United States Coast Guard in 1950, Canada in 1951 and the NSA in 1959 (though the NSA continued to use its own TSEC telecommunications security nomenclature [ 3 ] ). In 1957 the U.S. Department of Defense approved a military standard for the nomenclature, MIL-STD-196. The system has been modified over time, with some types (e.g. carrier pigeon -B- ) dropped and others (e.g. computers and cryptographic equipment) added. The latest version, MIL-STD-196G, was issued in 2018. [ 1 ] | https://en.wikipedia.org/wiki/Joint_Electronics_Type_Designation_System |
The Joint Enterprise Defense Infrastructure ( JEDI ) contract was a large United States Department of Defense cloud computing contract which has been reported as being worth $10 billion [ 1 ] [ 2 ] over ten years. JEDI was meant to be a commercial off-the-shelf (COTS) implementation of existing technology, while providing economies of scale to DoD.
Companies interested in the contract included Amazon , Google , Microsoft and Oracle . [ 3 ] After protests from Google employees, Google decided to drop out of contention for the contract because of conflict with its corporate values. [ 4 ] The deal was considered "gift-wrapped for Amazon" until Oracle (co-chaired by Safra Catz ) contested the contract, citing the National Defense Authorization Act over IDIQ contracts and the conflicts of interest from Deap Ubhi , who worked for Amazon both before and after his time in the Department of Defense. This led Eric G. Bruggink , senior judge of the United States Court of Federal Claims , to place the contract award on hold. [ 5 ] [ 6 ]
In August 2019, weeks before the winner was expected to be announced, President Donald Trump ordered the contract placed on hold again for Defense Secretary Mark Esper to investigate complaints of favoritism towards Amazon. [ 7 ] In October 2019, it was announced that the contract was awarded to Microsoft. Media has noted Trump's dislike towards Amazon's founder, Jeff Bezos , owner of the Washington Post , a newspaper critical of Trump. [ 8 ] [ 9 ] According to Bezos, Trump "used his power to 'screw Amazon' out of the JEDI Contract". [ 10 ] The JEDI contract was awarded to Microsoft on October 25, 2019, the DoD announced, [ 11 ] but AWS filed documents with the Court of Federal Claims on November 22, 2019 challenging the award; [ 12 ] its legal strategy included calling Trump to testify. [ 13 ]
A federal judge, Patricia Campbell-Smith, halted Microsoft's work on the project on February 13, 2020, a day before the system was scheduled to go live, awaiting a resolution in Amazon's suit. [ 14 ] She said that Amazon's claims are reasonable and "is likely to succeed on the merits of its argument that the DOD improperly evaluated" Microsoft's offer. [ 15 ] [ 16 ] As a result, the DOD was forced by a federal judge to reopen bidding for the contract. In the wake of that reopening, Amazon has filed additional protests related to modifications which have been made to selected sections of the contract. [ 17 ] Recent DOD legal filings have stated that the final award of the contract cannot take place until at least August 17, and may yet be delayed beyond that date as well. [ 18 ] On September 4, 2020, the Department of Defense reaffirmed that Microsoft won the JEDI Cloud contract after the reevaluation of the proposal, stating that Microsoft's proposal continues to represent the best value to the government. [ 19 ] DISA/CCPO ( Defense Information Systems Agency / Cloud Computing Program Office ) had not yet begun work, as of May 29, 2021, while Microsoft continued to mark time before an implementation. [ 20 ] In the meantime the several departments (Army, Navy, Air Force) are using their previous infrastructures to meet their several internal time lines, respectively. [ citation needed ]
The JEDI contract with Microsoft was cancelled on July 6, 2021 with the expectation that a new program called "Joint Warfighter Cloud Capability" (JWCC) would replace it, which would involve services from multiple vendors. [ 21 ] [ 22 ] On November 19, 2021 the Department of Defense issued formal solicitations to four of the original JEDI companies: Amazon, Google, Microsoft and Oracle; notably not including the fifth provider consulted, IBM. [ 23 ] On December 7, 2022, the JWCC contract was awarded to the four companies for a combined total of up to $9 billion under the program. [ 24 ]
This computing article is a stub . You can help Wikipedia by expanding it .
This military -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Joint_Enterprise_Defense_Infrastructure |
The Joint European Disruptive Initiative (JEDI) is a European funding agency aiming at promoting disruptive technologies . It funds innovation in different "missions" (environment and energy, healthcare , education, digital, space, and oceans), [ 1 ] with the goal of bringing " Europe in a leadership position in breakthrough technologies". [ 2 ] [ 3 ] It organizes scientific competitions focused on disruptive technologies. [ 4 ] JEDI also makes policy recommendations to strengthen European technology sovereignty. [ 5 ] As of 2024 [update] , JEDI was funding the projects of over 6,000 researchers in 29 countries across Europe and the world. It is operated independently from any European governments with funding from foundations, companies, individuals and public institutions. [ 6 ]
JEDI was inspired by DARPA (Defense Advanced Research Projects Agency), [ 7 ] the technology research and development agency of the United States Department of Defense . JEDI calls itself a "precursor" to a European advanced research projects agency. [ 6 ]
The Joint European Disruptive Initiative launched its first "Darpa-type GrandChallenge" [ 8 ] on Covid-19 on May 5, 2020. [ 9 ] The competition consisted in screening "billions of molecules with blocking interactions on SARS-CoV-2 " to develop a drug against the coronavirus — with each participant having to use at least three different calculation methods for the simulations. [ 10 ] The foundation claims to have had approximately 54 billions of molecules screened [ 11 ] and 878 of them being synthesized. A paper published in Nature showed that the protein PDB 6W9C was one of the most used in silico drug design against Covid-19 . [ 12 ] | https://en.wikipedia.org/wiki/Joint_European_Disruptive_Initiative |
The Joint Evaluated Fission and Fusion ( JEFF ) organization is an international collaboration for the production of nuclear data . It consists of members of the Nuclear Energy Agency (NEA) of the Organisation for Economic Co-operation and Development (OECD). [ 1 ]
JEFF produces the Joint Evaluated Fission and Fusion Nuclear Data Library , which is in the universal ENDF format.
This nuclear physics or atomic physics –related article is a stub . You can help Wikipedia by expanding it .
This article about a scientific organization is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Joint_Evaluated_Fission_and_Fusion |
Joint Expert Speciation System ( JESS ) is a package of computer software and data [ 1 ] [ 2 ] [ 3 ] developed collaboratively at Murdoch University and elsewhere by researchers interested in the chemical thermodynamics of water solutions with important applications in industry, biochemistry, medicine and the environment. Using information from the chemical literature, stored in databases for numerous chemical properties, JESS achieves coherence between frequently conflicting sources by automatic methods. [ 2 ]
JESS places a strong emphasis on the concept of chemical speciation ( i.e . the identity and relative abundance of different chemical entities which may be present), which can be predicted from known stability constants of metal-ligand complexes . Characteristic quantities for water solutions such as solubilities , equilibrium constants , activity coefficients , heat capacities and densities can be calculated from changes in the chemical speciation.
Recent examples of practical problems that can be investigated by JESS include kidney stones (mineral precipitation and dissolution in the kidney) [ 4 ] and Wilson’s disease (copper physiology in the human eye). [ 5 ]
At the core of the software package is a thermodynamic database called the ‘JESS Parent Database’ (JPD). JPD now comprises over 80,000 chemical reactions for which some 280,000 equilibrium constants and other thermodynamic parameters have been recorded from the chemical literature. Over 70,000 distinct chemical species are involved. The whole contents of this database in a set of associated PDF documents, which have been specifically prepared for free, widespread scientific dissemination, are available at the Zenodo repository. [ 6 ] | https://en.wikipedia.org/wiki/Joint_Expert_Speciation_System |
The Joint FAO/WHO Expert Committee on Food Additives ( JECFA ) is an international scientific expert committee that is administered jointly by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). It has been meeting since 1956 to provide independent scientific advice pertaining to the safety evaluation of food additives . Its current scope of work now also includes the evaluation of contaminants, naturally occurring toxicants and residues of veterinary drugs in food.
As the FAO/WTO publication describes, global food safety can be difficult to ensure without international reference standards. [ 1 ] While all countries require access to reliable risk assessments of the various chemicals in our food, not all have the resources or the funds available to conduct such evaluations for a large number of substances. Through expert-driven risk assessments JECFA defines the safe exposure levels to chemicals found in food. JECFA plays a key role by providing scientific advice that is both reliable and independent, thereby contributing to the setting of standards on a global scale for the protection of consumer health while ensuring trade of safe food. [ 2 ] Over time JECFA has developed and updated the methods for risk assessments of chemicals in food. The Environmental Health Criteria 240 or EHC 240 captures this work and constitutes the international point of reference recognized by national and regional food safety authorities. [ 3 ]
JECFA normally meets twice a year. The meetings either cover (i) food additives, contaminants and naturally occurring toxicants in food or (ii) residues of veterinary drugs in food. Different sets of experts (called Members for the purposes of the meeting) are invited to these meetings to solicit their expertise depending on the topics being discussed. [ 4 ]
Sometimes FAO and WHO may also convene expert meetings to provide scientific advice on issues that are related to chemical food safety but fall outside the purview of JECFA. These ad hoc meetings are called either in response to specific requests from Codex, and/or to advise national authorities on risks or incidents that affect consumers’ health and have serious economic and trade repercussions. [ 4 ]
The work of the Codex Alimentarius Commission (CAC), which is the most important international body in the field of food standards, is based on the scientific advice provided by bodies like JECFA. [ 5 ] This advice to CAC is normally provided to the various Codex Committees, such as the Codex Committee on Food Additives (CCFA), Codex Committee on Contaminants in Food (CCCF), and the Codex Committee on Residues of Veterinary Drugs (CCVRDF). [ 5 ]
FAO, WHO and the member countries of both the organizations also benefit from the evaluations made by JECFA. Some use the information from JECFA to establish their own national food safety control programs. [ 5 ]
The JECFA Committee also develops principles for the safety assessment of chemicals in food that are consistent with current scientific knowledge on risk assessments, while taking into account the recent developments in toxicology and other relevant scientific areas such as epidemiology, biotechnology, exposure assessment, food chemistry including analytical chemistry and assessment of maximum residue limits for veterinary drugs. [ 4 ]
Resources produced for or after the JECFA meetings include: [ 4 ] | https://en.wikipedia.org/wiki/Joint_FAO/WHO_Expert_Committee_on_Food_Additives |
The Joint Global Ocean Flux Study ( JGOFS ) was an international research programme on the fluxes of carbon between the atmosphere and ocean , and within the ocean interior. Initiated by the Scientific Committee on Oceanic Research (SCOR), the programme ran from 1987 through to 2003, and became one of the early core projects of the International Geosphere-Biosphere Programme (IGBP).
The overarching goal of JGOFS was to advance the understanding of, as well as improve the measurement of, the biogeochemical processes underlying the exchange of carbon across the air—sea interface and within the ocean. The programme aimed to study these processes from regional to global spatial scales, and from seasonal to interannual temporal scales, and to establish their sensitivity to external drivers such as climate change . [ 1 ]
Early in the programme in 1988, two long-term time-series projects were established in the Atlantic and Pacific basins. These — Bermuda Atlantic Time-series Study (BATS) [ 2 ] and Hawaii Ocean Time-series (HOT) [ 3 ] — continue to make observations of ocean hydrography , chemistry and biology to the present-day. In 1989, JGOFS undertook the multinational North Atlantic Bloom Experiment (NABE) to investigate and characterise the annual spring bloom of phytoplankton , a key feature in the carbon cycle of the open ocean. [ 4 ]
An important aspect of JGOFS lay in its objective to develop an increased network of observations, made using routine procedures, and curated such that they were easily available to researchers. [ 1 ] JGOFS also oversaw the development of models of the marine system based on understanding gained from its observational programme. [ 5 ] | https://en.wikipedia.org/wiki/Joint_Global_Ocean_Flux_Study |
The Joint Interface Control Officer (JICO) is the senior multi-tactical data link interface control officer in support of joint task force operations. The JICO is responsible for effecting planning and management of the joint tactical data link network within a theater of operations . [ 1 ]
This military -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Joint_Interface_Control_Officer |
The Joint Precision Airdrop System (JPADS) is an American military airdrop system which uses the Global Positioning System (GPS), steerable parachutes , and an onboard computer to steer loads to a designated point of impact (PI) on a drop zone (DZ). The JPADS family of systems consists of several precision airdrop systems, ranging from extra light to heavy payloads. JPADS is used in conjunction with mission planning software that resides on a laptop. The function of this mission planning software includes computing release points, weather forecasting , acquiring measurements of wind velocity, altitude, air pressure, and temperature. It can also receive weather updates and en route mission changes through satellite links.
U.S. Army Research, Development and Engineering Command (RDECOM) was the primary developer for JPADS, which meets several requirements: increased ground accuracy, standoff delivery, increased air carrier survivability, and improved effectiveness/assessment feedback regarding airdrop mission operations. The U.S. Army and U.S. Air Force began jointly developing this system in 1993. The U.S. Air Force made its first operational/combat use of the system in Afghanistan in 2006. [ 1 ]
The steerable parachute or parafoil is called a "decelerator," and gives the JPADS system directional control throughout its descent by means of decelerator steering lines attached to the Autonomous Guidance Unit (AGU). They create drag on either side of the decelerator, which turns the parachute, thus achieving directional control.
The AGU contains a GPS, a battery pack , and the guidance, navigation and control (GN&C) software package. It also houses the hardware required to operate the steering lines. The AGU obtains its position prior to exiting the aircraft, and continues to calculate its position via the GPS throughout descent.
The Mission Planner software gives the aircrew the ability to plan the mission, in flight if necessary, as well as steer the aircraft to its Computed Air Release Point (CARP), where the load is released.
JPADS involves four increments, categorized by the weight of the cargo to be dropped:
Increment I: JPADS-2K / applies to loads up to 2,200 lb / classified as the “extra light” category / commensurate with Container Delivery System (CDS) bundles.
Increment II: JPADS-10K / applies to loads up to 10,000 lb.
Increment III: JPADS-30K / applies to loads up to 30,000 lb.
Increment IV: JPADS-60K / applies to loads up to 60,000 lb.
JPADS is reported to be accurate to 50–75 metres (164–246 ft), drastically reduces drop zone size requirements; significantly increasing the number of locations which can be used as a drop zone. This reduces both the risk of hostile fire to aircraft and aircrews and the amount of cargo that misses a drop zone. [ 2 ]
JPADS offers several main benefits, including an increase in the number of available drop zones and an increase in the cargo's precision, which benefits the user. JPADS also increases the survivability of the delivery aircraft and its crew.
Current drop zones are quite large; 600 yd (549 m) or more. Airdropping sequential loads (multiple loads aboard a single aircraft) requires very long drop zones on the order of 0.5 mi (0.8 km) or more, or else the aircraft must make multiple passes over the same area, a tactically unsound thing to do. Furthermore, achieving a high degree of accuracy (less than 100 yd (91 m)) requires the aircraft to fly at the lowest altitude possible, which can range from 400 ft (122 m) above ground level to as high as 1,500 ft (457 m), depending on the altitude of the drop zone, the weight of the load, and the number and type of parachutes required.
JPADs can achieve the same or better accuracy from greater heights, allowing the aircraft to drop the load at a much higher, and usually safer, altitude.
Because JPADS allows the aircraft to drop at high-altitude, the aircraft can actually drop the load a good distance away from the drop zone, which affords the aircrew to remain free of enemy threats which may be near the area where the load is being dropped.
Airdrops are usually performed at slow speeds for an aircraft, usually 130 kts for paratroopers and 140 kts for cargo. When combined with the low altitude required for precision, the aircraft are vulnerable to enemy ground fire. With JPADS, the aircraft is much more likely to survive, as it can drop at a much higher altitude, above most enemy ground fire.
Because the system can transmit its current position back to the airdrop aircraft, it provides its exact landing location which the aircrew can then transmit to ground forces which may not have arrived at the drop zone. | https://en.wikipedia.org/wiki/Joint_Precision_Airdrop_System |
The Joint Regional Information Exchange System ( JRIES ) began in December 2002 as an all-source intelligence / information sharing system, designed initially as a grassroots pilot system to connect the California Anti-Terrorism Information Center, the New York Police Department, and the Defense Intelligence Agency (DIA).
These groups designed JRIES, which was first deployed in February 2003, to facilitate the exchange of suspicious activity reports, register events potentially related to terrorist activity, and foster real-time intelligence and law enforcement collaboration in a secure environment across federal, state, and local jurisdictions. JRIES used a commercial, off-the-shelf software collaboration tool application to enable multiple groups to share the information securely. A JRIES executive board, composed of representatives from the participating groups, provided guidance and structure to help manage the system. JRIES proved useful during the northeast blackout in 2003 when information posted on the system allowed users across the country to quickly learn that the event was not related to terrorism. The system provided a very simple and efficient way for the law enforcement community to obtain situational awareness concurrently, without the need for hundreds of phone calls.
Although DIA originally operated and maintained JRIES, DIA transferred program management of the system to the U.S. Department of Homeland Security (DHS) in September 2003, due to funding constraints. DIA was concerned that managing JRIES to support domestic intelligence activities conflicted with its military intelligence role. As of February 2004, approximately 100 organizations–with more than 1,000 law enforcement and intelligence analysts from federal, state, and local government agencies—were using JRIES.
After acquiring JRIES, DHS recognized that the system's utility could be expanded beyond its existing counter-terrorism intelligence and threat awareness mission because JRIES met DHS' requirements for senior executive communications, crisis planning and management, and coordination and communications with first responder, emergency management, and military organizations. As such, in February 2004, DHS announced the expansion of JRIES as its primary communication, collaboration, situational awareness, and information-sharing system. The DHS Secretary renamed JRIES as the Homeland Security Information Network ( HSIN ) in order to reflect the system's broader scope. By December 2004, DHS had deployed HSIN to all 50 states, 53 major urban areas, five U.S. territories, the District of Columbia, and several international partners. DHS extended HSIN access beyond the law enforcement community to include state homeland security advisors, governors' offices, emergency managers, first responders, the National Guard, and an international component. DHS equipped each location with two laptops installed with the commercial, off-the-shelf software collaboration tool application.
In February 2004, because of the lack of scalability to accommodate a large increase in users, DHS decided to move HSIN away from the current software collaboration tool and to develop a series of web-based portals as replacements. Nonetheless, DHS continues to operate both the commercial software collaboration tool application and a portal to support the law enforcement community.
DHS has expanded the role of HSIN through a state and local initiative. The goals of this initiative are to identify and address requirements of state and local communities of interest, as well as to provide robust training to promote effective use of the network. As of January 2006, eight states had deployed HSIN throughout their respective departments and agencies. Declaring HSIN the primary system for operational information sharing and collaboration, the DHS Secretary asked that the department's senior managers as well as headquarters and field personnel support the ongoing growth and utilization of HSIN.
By Alice Lipowicz, Contributing Staff Writer: GCN.com https://web.archive.org/web/20080408024104/http://www.gcn.com/online/vol1_no1/37223-1.html | https://en.wikipedia.org/wiki/Joint_Regional_Information_Exchange_System |
Joint Service Lightweight Integrated Suit Technology ( JSLIST ), also known as Advanced Chemical Protective Garment ( ACPG ) by the U.S. Navy , is a suit used by the U.S. Military for protection against CBRN hazards. It is part of the MOPP ensemble. The JSLIST is made to be worn over the Battle Dress Uniform . The suit consists of lightweight chemical and biological protective clothing consisting of a two piece suit, overboots, gloves, and respiratory equipment. [ 1 ] The suit is air permeable to allow breathing to help with the user's comfort and reduce heat stress. The JSLIST has a 120-day service life when removed from packaging, can be worn for 45 consecutive days in an uncontaminated environment, and can be cleaned up to 6 times.
In 1993, command groups from the Marine Corps , Navy , Army , and Air Force signed an agreement that created the JSLIST program, to replace the Chemical Protection Overgarment used by the U.S. Navy. The JSLIST program worked on creating, testing, and manufacturing a better and unified CBRN protective suit for a reduced cost. The U.S. Military started procurement of the JSLIST in 1997. [ 2 ]
The JSLIST Overgarment includes the coat and trousers. Both pieces are made from 50/50 nylon/cotton rip-stop material with a waterproof coating for the outer material. [ 3 ] The inner material includes an activated charcoal layer. The overgarment comes in desert and woodland camouflage . The trousers have bellows pockets, adjustable suspenders and waistband, and a slide fastener with protective flap. [ 3 ] The coat is waist long, has a slide fastener and protective flap, and has an integral hood. [ 3 ] Multipurpose Rain, Snow, and CB overboot (MOLO) are used for footwear for the ensemble. [ 3 ] Butyl gloves and respiratory equipment are also used to complete the suit. [ 3 ] Military personnel often wrap M9 Detector Tape around the sleeve and trouser leg of the JSLIST for chemical agent detection. [ 4 ]
Joint Firefighter Integrated Response Ensemble (J-FIRE) is a military protective suit used for firefighting in the CBRN and WMD environment. [ 3 ] J-FIRE utilizes the JSLIST and an aluminized firefighting proximity suit. The J-FIRE is designed to resist water and standard firefighting chemicals, while still providing CBRN protection to the user. The U.S. Army started use of the J-FIRE suit in 1997. [ 5 ] | https://en.wikipedia.org/wiki/Joint_Service_Lightweight_Integrated_Suit_Technology |
Joint application design is a term originally used to describe a software development process pioneered and deployed during the mid-1970s by the New York Telephone Company 's Systems Development Center under the direction of Dan Gielan. Following a series of implementations of this methodology, Gielan lectured extensively in various forums on the methodology and its practices. Arnie Lind, then a Senior Systems Engineer at IBM Canada in Regina, Saskatchewan created and named joint application design in 1974. Existing methods, however, entailed application developers spending months learning the specifics of a particular department or job function, and then developing an application for the function or department. In addition to development backlog delays, this process resulted in applications taking years to develop, and often not being fully accepted by the application users.
Arnie Lind's idea was that rather than have application developers learn about people's jobs, people doing the work could be taught how to write an application. Arnie pitched the concept to IBM Canada's Vice President Carl Corcoran (later President of IBM Canada), and Carl approved a pilot project. Arnie and Carl together named the methodology JAD, an acronym for joint application design, after Carl Corcoran rejected the acronym JAL, or joint application logistics, upon realizing that Arnie Lind's initials were JAL (John Arnold Lind).
The pilot project was an emergency room project for the Saskatchewan Government. Arnie developed the JAD methodology, and put together a one-week seminar, involving primarily nurses and administrators from the emergency room, but also including some application development personnel. The one-week seminar produced an application framework, which was then coded and implemented in less than one month, versus an average of 18 months for traditional application development. And because the users themselves designed the system, they immediately adopted and liked the application. After the pilot project, IBM was very supportive of the JAD methodology, as they saw it as a way to more quickly implement computing applications, running on IBM hardware.
Arnie Lind spent the next 13 years at IBM Canada continuing to develop the JAD methodology, and traveling around the world performing JAD seminars, and training IBM employees in the methods and techniques of JAD. JADs were performed extensively throughout IBM Canada, and the technique also spread to IBM in the United States. Arnie Lind trained several people at IBM Canada to perform JADs, including Tony Crawford and Chuck Morris. Arnie Lind retired from IBM in 1987, and continued to teach and perform JADs on a consulting basis, throughout Canada, the United States, and Asia.
The JAD process was formalized by Tony Crawford and Chuck Morris of IBM in the late 1970s. It was then deployed at Canadian International Paper. JAD was used in IBM Canada for a while before being brought back to the US. Initially, IBM used JAD to help sell and implement a software program they sold, called COPICS. It was widely adapted to many uses (system requirements, grain elevator design, problem-solving, etc.). Tony Crawford later developed JAD-Plan and then JAR (joint application requirements). In 1985, Gary Rush wrote about JAD and its derivations – Facilitated Application Specification Techniques (FAST) – in Computerworld. [ 1 ]
Originally, JAD was designed to bring system developers and users of varying backgrounds and opinions together in a productive as well as creative environment. The meetings were a way of obtaining quality requirements and specifications. The structured approach provides a good alternative to traditional serial interviews by system analysts. JAD has since expanded to cover broader IT work as well as non-IT work (read about Facilitated Application Specification Techniques – FAST – created by Gary Rush in 1985 to expand JAD applicability. [ 2 ] | https://en.wikipedia.org/wiki/Joint_application_design |
In anatomy , a joint capsule or articular capsule is an envelope surrounding a synovial joint . [ 1 ] Each joint capsule has two parts: an outer fibrous layer or membrane, and an inner synovial layer or membrane.
Each capsule consists of two layers or membranes:
On the inside of the capsule, articular cartilage covers the end surfaces of the bones that articulate within that joint.
The outer layer is highly innervated by the same nerves which perforate through the adjacent muscles associated with the joint.
The fibrous membrane of the joint capsule is attached to the whole circumference of the articular end of each bone entering into the joint, and thus entirely surrounds the articulation. It is made up of dense connective tissue . It's a long spongy tissue.
Frozen shoulder (adhesive capsulitis) is a disorder in which the shoulder capsule becomes inflamed.
Plica syndrome is a disorder in which the synovial plica becomes inflamed and causes abnormal biomechanics in the knee.
This article incorporates text in the public domain from page 282 of the 20th edition of Gray's Anatomy (1918) | https://en.wikipedia.org/wiki/Joint_capsule |
Joint constraints are rotational constraints on the joints of an artificial system. [ 1 ] They are used in an inverse kinematics chain, in fields including 3D animation or robotics . [ 2 ] Joint constraints can be implemented in a number of ways, but the most common method is to limit rotation about the X, Y and Z axis independently. An elbow, for instance, could be represented by limiting rotation on X and Z axis to 0 degrees, and constraining the Y-axis rotation to 130 degrees.
To simulate joint constraints more accurately, dot-products can be used with an independent axis to repulse the child bones orientation from the unreachable axis. Limiting the orientation of the child bone to a border of vectors tangent to the surface of the joint, repulsing the child bone away from the border, can also be useful in the precise restriction of shoulder movement.
This computational physics -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Joint_constraints |
In universal algebra and model theory , a class of structures K is said to have the joint embedding property if for all structures A and B in K , there is a structure C in K such that both A and B have embeddings into C .
It is one of the three properties used to define the age of a structure.
A first-order theory has the joint embedding property if the class of its models of has the joint embedding property. [ 1 ] A complete theory has the joint embedding property. Conversely a model-complete theory with the joint embedding property is complete. [ 1 ]
A similar but different notion to the joint embedding property is the amalgamation property . To see the difference, first consider the class K (or simply the set) containing three models with linear orders , L 1 of size one, L 2 of size two, and L 3 of size three. This class K has the joint embedding property because all three models can be embedded into L 3 . However, K does not have the amalgamation property. The counterexample for this starts with L 1 containing a single element e and extends in two different ways to L 3 , one in which e is the smallest and the other in which e is the largest. Now any common model with an embedding from these two extensions must be at least of size five so that there are two elements on either side of e .
Now consider the class of algebraically closed fields . This class has the amalgamation property since any two field extensions of a prime field can be embedded into a common field. However, two arbitrary fields cannot be embedded into a common field when the characteristic of the fields differ.
This mathematical logic -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Joint_embedding_property |
In audio engineering , joint encoding is the joining of several channels of similar information during encoding in order to obtain higher quality, a smaller file size, or both.
The term joint stereo has become prominent as the Internet has allowed for the transfer of relatively low bit rate , acceptable-quality audio with modest Internet access speeds. Joint stereo refers to any number of encoding techniques used for this purpose. Two forms are described here, both of which are implemented in various ways with different codecs , such as MP3 , AAC and Ogg Vorbis .
This form of joint stereo uses a technique known as joint frequency encoding , which functions on the principle of sound localization . Human hearing is predominantly less acute at perceiving the direction of certain audio frequencies. By exploiting this characteristic, intensity stereo coding can reduce the data rate of an audio stream with little or no perceived change in apparent quality.
More specifically, the dominance of inter-aural time differences (ITD) for sound localization by humans is only present for lower frequencies. That leaves inter-aural amplitude differences (IAD) as the dominant location indicator for higher frequencies (the cutoff being ~2 kHz). The idea of intensity stereo coding is to merge the lower spectrum into just one channel (thus reducing overall differences between channels) and to transmit a little side information about how to pan certain frequency regions to recover the IAD cues. ITD is not lost completely in this scheme, however: the shape of the ear makes it such that the ITD can be recovered from IAD if the sound comes from free space, e.g. played through loudspeakers. [ 1 ]
This type of coding does not perfectly reconstruct the original audio because of the loss of information which results in the simplification of the stereo image and can produce perceptible compression artifacts . However, for very low bit rates this type of coding usually yields a gain in perceived quality of the audio. It is supported by many audio compression formats (including MP3 , AAC , Vorbis and Opus ) but not always by every encoder.
M/S stereo coding transforms the left and right channels into a mid channel and a side channel. The mid channel is the sum of the left and right channels, or M = L + R {\displaystyle M=L+R} . The side channel is the difference of the left and right channels, or S = L − R {\displaystyle S=L-R} . Unlike intensity stereo coding, M/S coding is a special case of transform coding , and retains the audio perfectly without introducing artifacts. Lossless codecs such as FLAC or Monkey's Audio use M/S stereo coding because of this characteristic.
To reconstruct the original signal, the channels are either added L = M + S 2 {\textstyle L={\frac {M+S}{2}}} or subtracted R = M − S 2 {\textstyle R={\frac {M-S}{2}}} .
This form of coding is also sometimes known as matrix stereo [ a ] and is used in many different forms of audio processing and recording equipment. It is not limited to digital systems and can even be created with passive audio transformers or analog amplifiers . One example of the use of M/S stereo is in FM stereo broadcasting, where L + R {\displaystyle L+R} modulates the carrier wave and L − R {\displaystyle L-R} modulates a subcarrier . This enables backwards compatibility with mono equipment, which will only require the mid channel. [ 2 ] Another example of M/S stereo is the stereophonic microgroove record . Lateral motions of a stylus represent the sum of two channels and the vertical motion represents the difference between the channels; two perpendicular coils mechanically decode the channels. [ 3 ]
M/S is also a common technique for production of stereo recordings. See Microphone practice § M/S technique .
M/S encoding does not strictly require that the left and right channels use the same weight. In Opus CELT, M/S encoding is combined with an angle parameter, so that different weights can be used to maximize de-correlation. [ 4 ] : 4.5.1
A similar form of joining multiple channels is seen in the ambisonics implementation of Opus 1.3. A matrix may be used to mix the spherical harmonic channels together, reducing redundancy. [ 5 ]
Parametric stereo is similar to intensity stereo, except that parameters beyond the intensity difference is used. In the MPEG-4 (HE-AAC) version, the intensity difference and time delay difference are used, allowing all bands to be used without hurting localization. HE-AAC also adds "correlation" information, which replicates ambience by synthesizing some difference between channels. [ 6 ]
Binaural cue coding (BCC) is the HE-AAC PS technique extended for many input channels, all downmixing to one. The very same ILD, ITD, and IC parameters were used. MPEG Surround is similar to BCC, but allows downmixing to multiple channels, and does not seem to use ITD. [ 7 ]
Joint frequency encoding is an encoding technique used in audio data compression to reduce the data rate .
The idea is to merge a given frequency range of multiple sound channels together so that the resulting encoding will preserve the sound information of that range not as a bundle of separate channels but as one homogeneous data stream. This will destroy the original channel separation permanently, as the information cannot be accurately reconstructed, but will greatly lessen the amount of required storage space. Only some forms of joint stereo use the joint frequency encoding technique, such as intensity stereo coding.
When used within the MP3 compression process, joint stereo normally employs multiple techniques, and can switch between them for each MPEG frame. Typically, a modern encoder's joint stereo mode uses M/S stereo for some frames and L/R stereo for others, whichever method yields the best result. Encoders use different algorithms to determine when to switch and how much space to allocate to each channel; quality can suffer if the switching is too frequent or if the side channel doesn't get enough bits. With some encoding software, it is possible to force the use of M/S stereo for all frames, mimicking the joint stereo mode of some early encoders like Xing . Within the LAME encoder, this is known as forced joint stereo. [ 8 ]
As with MP3, Ogg Vorbis stereo files can employ either L/R stereo or joint stereo. When using joint stereo, both M/S stereo and intensity stereo methods may be used. As opposed to MP3 where M/S stereo (when used) is applied before quantization, an Ogg Vorbis encoder applies M/S stereo to samples in the frequency domain after quantization, making application of M/S stereo a lossless step. After this step, any frequency area can be converted to intensity stereo by removing the corresponding part of the M/S signal's side channel. Ogg Vorbis' floor function will take care of the required left-right panning. [ citation needed ] Opus similarly has support for all three options in the CELT layer; the SILK layer is M/S-only. [ 9 ] | https://en.wikipedia.org/wiki/Joint_encoding |
In information theory , joint entropy is a measure of the uncertainty associated with a set of variables . [ 1 ]
The joint Shannon entropy (in bits ) of two discrete random variables X {\displaystyle X} and Y {\displaystyle Y} with images X {\displaystyle {\mathcal {X}}} and Y {\displaystyle {\mathcal {Y}}} is defined as [ 2 ] : 16
where x {\displaystyle x} and y {\displaystyle y} are particular values of X {\displaystyle X} and Y {\displaystyle Y} , respectively, P ( x , y ) {\displaystyle P(x,y)} is the joint probability of these values occurring together, and P ( x , y ) log 2 [ P ( x , y ) ] {\displaystyle P(x,y)\log _{2}[P(x,y)]} is defined to be 0 if P ( x , y ) = 0 {\displaystyle P(x,y)=0} .
For more than two random variables X 1 , . . . , X n {\displaystyle X_{1},...,X_{n}} this expands to
where x 1 , . . . , x n {\displaystyle x_{1},...,x_{n}} are particular values of X 1 , . . . , X n {\displaystyle X_{1},...,X_{n}} , respectively, P ( x 1 , . . . , x n ) {\displaystyle P(x_{1},...,x_{n})} is the probability of these values occurring together, and P ( x 1 , . . . , x n ) log 2 [ P ( x 1 , . . . , x n ) ] {\displaystyle P(x_{1},...,x_{n})\log _{2}[P(x_{1},...,x_{n})]} is defined to be 0 if P ( x 1 , . . . , x n ) = 0 {\displaystyle P(x_{1},...,x_{n})=0} .
The joint entropy of a set of random variables is a nonnegative number.
The joint entropy of a set of variables is greater than or equal to the maximum of all of the individual entropies of the variables in the set.
The joint entropy of a set of variables is less than or equal to the sum of the individual entropies of the variables in the set. This is an example of subadditivity . This inequality is an equality if and only if X {\displaystyle X} and Y {\displaystyle Y} are statistically independent . [ 2 ] : 30
Joint entropy is used in the definition of conditional entropy [ 2 ] : 22
and
For two variables X {\displaystyle X} and Y {\displaystyle Y} , this means that
Joint entropy is also used in the definition of mutual information [ 2 ] : 21
In quantum information theory , the joint entropy is generalized into the joint quantum entropy .
The above definition is for discrete random variables and just as valid in the case of continuous random variables. The continuous version of discrete joint entropy is called joint differential (or continuous) entropy . Let X {\displaystyle X} and Y {\displaystyle Y} be a continuous random variables with a joint probability density function f ( x , y ) {\displaystyle f(x,y)} . The differential joint entropy h ( X , Y ) {\displaystyle h(X,Y)} is defined as [ 2 ] : 249
For more than two continuous random variables X 1 , . . . , X n {\displaystyle X_{1},...,X_{n}} the definition is generalized to:
The integral is taken over the support of f {\displaystyle f} . It is possible that the integral does not exist in which case we say that the differential entropy is not defined.
As in the discrete case the joint differential entropy of a set of random variables is smaller or equal than the sum of the entropies of the individual random variables:
The following chain rule holds for two random variables:
In the case of more than two random variables this generalizes to: [ 2 ] : 253
Joint differential entropy is also used in the definition of the mutual information between continuous random variables: | https://en.wikipedia.org/wiki/Joint_entropy |
In the United States Armed Forces , the joint precision approach and landing system ( JPALS ) is an all-weather system for precision guidance of landing aircraft. It is based on real-time differential correction of the Global Positioning System (GPS) signal, augmented with a local area correction message, and transmitted to the user via secure means. It is used on terrestrial airfields as well as the US Navy 's amphibious assault ships and aircraft carriers ( hull classifications LH and CVN, respectively).
The onboard receiver compares the current GPS-derived position with the local correction signal, deriving a highly accurate three-dimensional position capable of being used for all-weather approaches via an Instrument Landing System -style display. Accuracy, while classified, is believed to be about 1 m or better. While JPALS is similar to Local Area Augmentation System , but intended primarily for use by the military, some elements of JPALS may eventually see their way into civilian use to help protect high-value civilian operations against unauthorized signal alteration.
The development of JPALS was the result of two main military requirements. First, the military needs an all-service, highly mobile all-weather precision approach system, tailorable to a wide range of environments, from shipboard use to rapid installation at makeshift airfields. Second, they need a robust system that can maintain a high level of reliability in combat operations, particularly in its ability to effectively resist jamming.
JPALS encompasses two main categories: SRGPS (shipboard relative GPS ) and LDGPS (land/local differential GPS). SRGPS provides highly accurate approach positioning for operations aboard ship, including aircraft carriers, helo and STO/VL carriers, and other shipboard operations, primarily helicopter operations.
LDGPS is further divided into three sub-categories: fixed base, tactical, and special missions. Fixed base is used for ongoing operations at military airfields around the world, while the tactical system is portable, designed for relatively short-term, austere airfield operations. The special missions system is a highly portable system capable of rapid installation and use by special forces .
The accuracy of local area augmentation system (LAAS) is better than CAT III ILS accuracy, and will provide horizontal and vertical resolutions of less than 1 m. Although the exact accuracy of JPALS will remain classified, it's estimated that JPALS will meet or exceed this accuracy for authorized users.
The main benefit of JPALS is that it's a system that can be taken anywhere, anytime, providing a safe and effective way to conduct 24/7, all-weather, anti-jam instrument landing system capability to all authorized users, worldwide. A secondary benefit is a significant reduction in cost over current systems.
The naval version of JPALS transmits a signal that has a low probability of intercept; so it is unlikely that an enemy will detect the signal and trace it back to its source. The existing system, tactical air navigation (TACAN), is not encrypted or concealed in any way, which can reveal the location of the ship on which it is installed. This is not acceptable in emissions control (EMCON) or stealth conditions.
The increase in both accuracy and reliability will significantly enhance operations while reducing non-operational periods due to weather or adversarial efforts. | https://en.wikipedia.org/wiki/Joint_precision_approach_and_landing_system |
The joint quantum entropy generalizes the classical joint entropy to the context of quantum information theory . Intuitively, given two quantum states ρ {\displaystyle \rho } and σ {\displaystyle \sigma } , represented as density operators that are subparts of a quantum system, the joint quantum entropy is a measure of the total uncertainty or entropy of the joint system. It is written S ( ρ , σ ) {\displaystyle S(\rho ,\sigma )} or H ( ρ , σ ) {\displaystyle H(\rho ,\sigma )} , depending on the notation being used for the von Neumann entropy . Like other entropies, the joint quantum entropy is measured in bits , i.e. the logarithm is taken in base 2.
In this article, we will use S ( ρ , σ ) {\displaystyle S(\rho ,\sigma )} for the joint quantum entropy.
In information theory , for any classical random variable X {\displaystyle X} , the classical Shannon entropy H ( X ) {\displaystyle H(X)} is a measure of how uncertain we are about the outcome of X {\displaystyle X} . For example, if X {\displaystyle X} is a probability distribution concentrated at one point, the outcome of X {\displaystyle X} is certain and therefore its entropy H ( X ) = 0 {\displaystyle H(X)=0} . At the other extreme, if X {\displaystyle X} is the uniform probability distribution with n {\displaystyle n} possible values, intuitively one would expect X {\displaystyle X} is associated with the most uncertainty. Indeed, such uniform probability distributions have maximum possible entropy H ( X ) = log 2 ( n ) {\displaystyle H(X)=\log _{2}(n)} .
In quantum information theory , the notion of entropy is extended from probability distributions to quantum states, or density matrices . For a state ρ {\displaystyle \rho } , the von Neumann entropy is defined by
Applying the spectral theorem , or Borel functional calculus for infinite dimensional systems, we see that it generalizes the classical entropy. The physical meaning remains the same. A maximally mixed state , the quantum analog of the uniform probability distribution, has maximum von Neumann entropy. On the other hand, a pure state , or a rank one projection, will have zero von Neumann entropy. We write the von Neumann entropy S ( ρ ) {\displaystyle S(\rho )} (or sometimes H ( ρ ) {\displaystyle H(\rho )} .
Given a quantum system with two subsystems A and B , the term joint quantum entropy simply refers to the von Neumann entropy of the combined system. This is to distinguish from the entropy of the subsystems.
In symbols, if the combined system is in state ρ A B {\displaystyle \rho ^{AB}} ,
the joint quantum entropy is then
Each subsystem has its own entropy. The state of the subsystems are given by the partial trace operation.
The classical joint entropy is always at least equal to the entropy of each individual system. This is not the case for the joint quantum entropy. If the quantum state ρ A B {\displaystyle \rho ^{AB}} exhibits quantum entanglement , then the entropy of each subsystem may be larger than the joint entropy. This is equivalent to the fact that the conditional quantum entropy may be negative, while the classical conditional entropy may never be.
Consider a maximally entangled state such as a Bell state . If ρ A B {\displaystyle \rho ^{AB}} is a Bell state, say,
then the total system is a pure state, with entropy 0, while each individual subsystem is a maximally mixed state, with maximum von Neumann entropy log 2 = 1 {\displaystyle \log 2=1} . Thus the joint entropy of the combined system is less than that of subsystems. This is because for entangled states, definite states cannot be assigned to subsystems, resulting in positive entropy.
Notice that the above phenomenon cannot occur if a state is a separable pure state. In that case, the reduced states of the subsystems are also pure. Therefore, all entropies are zero.
The joint quantum entropy S ( ρ A B ) {\displaystyle S(\rho ^{AB})} can be used to define of the conditional quantum entropy :
and the quantum mutual information :
These definitions parallel the use of the classical joint entropy to define the conditional entropy and mutual information . | https://en.wikipedia.org/wiki/Joint_quantum_entropy |
In information theory , joint source–channel coding is the encoding of a redundant information source for transmission over a noisy channel , and the corresponding decoding , using a single code instead of the more conventional steps of source coding followed by channel coding .
Joint source–channel coding has been proposed and implemented for a variety of situations, including speech and videotransmission. [ 1 ] [ 2 ]
This technology-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Joint_source_and_channel_coding |
In mathematics, the joint spectral radius is a generalization of the classical notion of spectral radius of a matrix, to sets of matrices. In recent years this notion has found applications in a large number of engineering fields and is still a topic of active research.
The joint spectral radius of a set of matrices is the maximal asymptotic growth rate of products of matrices taken in that set. For a finite (or more generally compact) set of matrices M = { A 1 , … , A m } ⊂ R n × n , {\displaystyle {\mathcal {M}}=\{A_{1},\dots ,A_{m}\}\subset \mathbb {R} ^{n\times n},} the joint spectral radius is defined as follows:
It can be proved that the limit exists and that the quantity actually does not depend on the chosen matrix norm (this is true for any norm but particularly easy to see if the norm is sub-multiplicative ). The joint spectral radius was introduced in 1960 by Gian-Carlo Rota and Gilbert Strang , [ 1 ] two mathematicians from MIT , but started attracting attention with the work of Ingrid Daubechies and Jeffrey Lagarias . [ 2 ] They showed that the joint spectral radius can be used to describe smoothness properties of certain wavelet functions . [ 3 ] A wide number of applications have been proposed since then. It is known that the joint spectral radius quantity is NP-hard to compute or to approximate, even when the set M {\displaystyle {\mathcal {M}}} consists of only two matrices with all nonzero entries of the two
matrices which are constrained to be equal. [ 4 ] Moreover, the question " ρ ≤ 1 ? {\displaystyle \rho \leq 1?} " is an undecidable problem . [ 5 ] Nevertheless, in recent years much progress has been done on its understanding, and it appears that in practice the joint spectral radius can often be computed to satisfactory precision, and that it moreover can bring interesting insight in engineering and mathematical problems.
In spite of the negative theoretical results on the joint spectral radius computability, methods have been proposed that perform well in practice. Algorithms are even known, which can reach an arbitrary accuracy in an a priori computable amount of time. These algorithms can be seen as trying to approximate the unit ball of a particular vector norm, called the extremal norm. [ 6 ] One generally distinguishes between two families of such algorithms: the first family, called polytope norm methods , construct the extremal norm by computing long trajectories of points. [ 7 ] [ 8 ] An advantage of these methods is that in the favorable cases it can find the exact value of the joint spectral radius and provide a certificate that this is the exact value.
The second family of methods approximate the extremal norm with modern optimization techniques , such as ellipsoid norm approximation, [ 9 ] semidefinite programming , [ 10 ] [ 11 ] Sum Of Squares , [ 12 ] and conic programming . [ 13 ] The advantage of these methods is that they are easy to implement, and in practice, they provide in general the best bounds on the joint spectral radius.
Related to the computability of the joint spectral radius is the following conjecture: [ 14 ]
"For any finite set of matrices M ⊂ R n × n , {\displaystyle {\mathcal {M}}\subset \mathbb {R} ^{n\times n},} there is a product A 1 … A t {\displaystyle A_{1}\dots A_{t}} of matrices in this set such that
In the above equation " ρ ( A 1 … A t ) {\displaystyle \rho (A_{1}\dots A_{t})} " refers to the classical spectral radius of the matrix A 1 … A t . {\displaystyle A_{1}\dots A_{t}.}
This conjecture, proposed in 1995, was proven to be false in 2003. [ 15 ] The counterexample provided in that reference uses advanced measure-theoretical ideas. Subsequently, many other counterexamples have been provided, including an elementary counterexample that uses simple combinatorial properties matrices [ 16 ] and a counterexample based on dynamical systems properties. [ 17 ] Recently an explicit counterexample has been proposed in. [ 18 ] Many questions related to this conjecture are still open, as for instance the question of knowing whether it holds for pairs of binary matrices . [ 19 ] [ 20 ]
The joint spectral radius was introduced for its interpretation as a stability condition for discrete-time switching dynamical systems . Indeed, the system defined by the equations
is stable if and only if ρ ( M ) < 1. {\displaystyle \rho ({\mathcal {M}})<1.}
The joint spectral radius became popular when Ingrid Daubechies and Jeffrey Lagarias showed that it rules the continuity of certain wavelet functions. Since then, it has found many applications, ranging from number theory to information theory, autonomous agents consensus, combinatorics on words ,...
The joint spectral radius is the generalization of the spectral radius of a matrix for a set of several matrices. However, many more quantities can be defined when considering a set of matrices: The joint spectral subradius characterizes the minimal rate of growth of products in the semigroup generated by M {\displaystyle {\mathcal {M}}} .
The p-radius characterizes the rate of growth of the L p {\displaystyle L_{p}} average of the norms of the products in the semigroup.
The Lyapunov exponent of the set of matrices characterizes the rate of growth of the geometric average. | https://en.wikipedia.org/wiki/Joint_spectral_radius |
Joinup is a collaboration platform created by the European Commission . It is funded by the European Union via its Interoperability Solutions for Public Administrations Programme (ISA Programme).
Joinup was launched on 9 December 2011. It replaced the Open Source Observatory and Repository (OSOR.eu) and the Semantic Interoperability Centre Europe (SEMIC.eu), themselves communities funded by the ISA Programme. These two became Joinup's initial communities.
The site aims to let public administrations promote their e-government systems.
More specifically, it offers a meeting place and a collaborative working environment for the development of interoperability . Joinup hosts communities of practice , such as the community for the Common Assessment Method for Standards and Specifications (CAMSS) [ 1 ] and the community for the National Interoperability Frameworks Observatory (NIFO). [ 2 ] The platform also raises awareness on free and open source software and semantic interoperability in the public sector . Joinup offers a catalogue of open source software, interoperability assets and models such as the Interoperability Maturity Model (IMM). [ 3 ] The target audience includes those using, developing and implementing e-government systems. The site focuses on the European public sector , but the projects are open to all others. [ 4 ]
The platform has three main functions: [ 5 ]
Joinup provides access to a Federation catalogue hosted by public administrations in EU member states and standardisation bodies such as the European Committee for Standardization (CEN) and European Telecommunications Standards Institute (ETSI).
Joinup is also used by the European Commission's Directorate General for Informatics to make available all of its applications. Examples include Circabc, [ 6 ] a document management system, Open e-Prior, [ 7 ] a tool to help manage electronic procurement, and OnLine Collection Software for ECI, [ 8 ] to help organisations gather signatures that support their request to the European Commission to propose legislation.
In December 2014, the ISA Programme added the ePractice community to the Joinup platform. ePractice offers services for the professional community of eGovernment, eInclusion and eHealth practitioners. [ 9 ] In January 2015, the OpenGovernment community [ 10 ] was added by the EC's Directorate General for Communications Networks, Content and Technology
A detailed list of all the potential services someone receives by registering at this platform can be found at JoinUp's website. [ 11 ]
A list of all the software contributions made by the community are at JoinUp's website. [ 12 ]
The Joinup platform is powered by a tailored version of the Drupal [ 13 ] content management framework (version 6) [ citation needed ] and can be downloaded from the Joinup web site. [ 14 ] Its latest version is 1.7.2 (released on March 15, 2015). [ 15 ] [ 16 ]
The source code of some past versions can be found at JoinUp's website. [ 17 ]
The development of the platform is done on hosts running Debian Linux. [ citation needed ]
The Joinup platform runs on 10 hosts in the EC's datacentre in Luxembourg . It includes a load balancer, some network-attached storage and a reverse-proxy. The main part of the platform is on three Red Hat Linux hosts, running Apache webserver and Drupal. A fourth
Linux host is running the Apache Tomcat Java server, the Apache Solr search engine and Apache Maven build automation tools. A fifth Linux
host is running the Apache Subversion software versioning and revisioning system. There is a sixth Linux host running the MySQL relational database system and a seventh for GNU Mailman .
The platform's software [ 18 ] is used to offer similar services involving
public administrations in other regions and countries. In Australia and New Zealand , the Openray platform [ 19 ] is being piloted since June
2012 by the Open Technology Foundation (OTF), a research organisation
supporting the government sector in the research, evaluation,
trialling and uptake of open technologies, standards and methods.
By 21 November 2013, all semantic services were federated and show up in the Openray repository.
Also on 21 November 2013, the government of South Australia announced that it would start piloting an internal version of
the Joinup platform software and test the use of the EC's Open
e-Prior. [ 20 ] Its aim is to improve collaboration and procurement activities. Openroad is a similar collaboration platform, begun by Vietnam 's Ministry of Science and Technology in January 2013. [ 21 ]
Joinup is itself a federation of other, similar projects, such as the
French Adullact. This was started in 2002 by the Association des
développeurs et utilisateurs de logiciels libres pour les
administrations et les collectivités territoriales, (Association of
developers and users of free software for governments and local
authorities). Adullact was actually an inspiration for the EC's
Open Source Observatory and Repository.
Other examples would be the Spanish Centro de Transferencia de
Tecnología (Centre for Technology Transfer), or La forja de
Guadalinex, hosted by Junta de Andalucia .
The platform could also be compared with the National Information Exchange Model (NIEM), an XML -based information exchange framework from the United States . However, NIEM is designed to develop,
disseminate, and support information exchange standards and processes that will enable jurisdictions to automate information sharing, the EC's Joinup is for sharing information technology.
Joinup might even be compared to the Comprehensive Knowledge Archive Network (CKAN). However, this focuses not on software packages or semantic assets, but on the storage and distribution of data, such as spreadsheets and the contents of databases. | https://en.wikipedia.org/wiki/Joinup |
A joist is a horizontal structural member used in framing to span an open space, often between beams that subsequently transfer loads to vertical members. When incorporated into a floor framing system, joists serve to provide stiffness to the subfloor sheathing, allowing it to function as a horizontal diaphragm . Joists are often doubled or tripled, placed side by side, where conditions warrant, such as where wall partitions require support.
Joists are either made of wood, engineered wood , or steel, each of which has unique characteristics. Typically, wood joists have the cross section of a plank with the longer faces positioned vertically. However, engineered wood joists may have a cross section resembling the Roman capital letter " I "; these joists are referred to as I -joists . Steel joists can take on various shapes, resembling the Roman capital letters "C", " I ", "L" and "S".
Wood joists were also used in old-style timber framing . The invention of the circular saw for use in modern sawmills has made it possible to fabricate wood joists as dimensional lumber .
Joists must exhibit the strength to support the anticipated load over a long period of time. In many countries, the fabrication and installation of all framing members including joists must meet building code standards. Considering the cross section of a typical joist, the overall depth of the joist is critical in establishing a safe and stable floor or ceiling system. The wider the spacing between the joists, the deeper the joist needs to be to limit stress and deflection under load. Lateral support called dwang , [ 1 ] blocking, [ 2 ] or strutting [ 2 ] increases its stability, preventing the joist from buckling under load. There are approved formulas for calculating the depth required and reducing the depth as needed; however, a rule of thumb for calculating the depth of a wooden floor joist for a residential property is to take half the span in feet, add two, and use the resulting number as the depth in inches; for example, the joist depth required for a 14-foot (4.3 m) span is 9 inches (230 mm). Many steel joist manufacturers supply load tables to allow designers to select the proper joist sizes for their projects.
Standard dimensional lumber joists have their limitations due to the limits of what farmed lumber can provide. Engineered wood products such as I-joists gain strength from expanding the overall depth of the joist, as well as by providing high-quality engineered wood for both the bottom and the top chords of the joist. A common saying regarding structural design is that "deeper is cheaper", referring to the more cost-effective design of a given structure by using deeper but more expensive joists, because fewer joists are needed and longer spans are achieved, which more than makes up for the added cost of deeper joists.
In traditional timber framing there may be a single set of joists which carry both a floor and ceiling called a single floor (single joist floor, single framed floor) or two sets of joists, one carrying the floor and another carrying the ceiling called a double floor (double framed floor). The term binding joist is sometimes used to describe beams at floor level running perpendicular to the ridge of a gable roof and joined to the intermediate posts . Joists which land on a binding joist are called bridging joists. [ 3 ] [ 4 ] A large beam in the ceiling of a room carrying joists is a summer beam . A ceiling joist may be installed flush with the bottom of the beam or sometimes below the beam. Joists left exposed and visible from below are called "naked flooring" or "articulated" (a modern U.S. term) and were typically planed smooth (wrought) and sometimes chamfered or beaded .
Joists may join to their supporting beams in many ways: joists resting on top of the supporting beams are said to be "lodged"; dropped in using a butt cog joint (a type of lap joint), half-dovetail butt cog, or a half-dovetail lap joint. Joists may also be tenoned in during the raising with a soffit tenon or a tusk tenon (possibly with a housing). Joists can also be joined by being slipped into mortises after the beams are in place such as a chase mortise (pulley mortise), L-mortise, or "short joist". Also, in some Dutch-American work, ground level joists are placed on a foundation and then a sill placed on top of the joists such as what timber frame builder Jack Sobon called an "inverted sill" or with a "plank sill".
Joists can have different joints on either ends such as being tenoned on one end and lodged on the other end.
A reduction in the under-side of cogged joist-ends may be square, sloped or curved. Typically joists do not tie the beams together, but sometimes they are pinned or designed to hold under tension. Joists on the ground floor were sometimes a pole (pole joist, half-round joist, log joist. A round timber with one flat surface) and in barns long joists were sometimes supported on a sleeper (a timber not joined to but supporting other beams).
Joists left out of an area form an opening called a "well" as in a stairwell or chimney-well. The joists forming the well are the heading joist (header) and trimming joist (trimmer). Trimmers take the name of the feature such as hearth trimmer, stair trimmer, etc.
Shortened joists are said to be crippled . The term rim joist is rare before the 1940s in America; it forms the edge of a floor. The outermost joist in half timber construction may be of a more durable species than the interior joists. In a barn, loose poles above the drive floor are called a scaffold . Between the joists, the area called a joist-bay, and above the ceiling in some old houses is material called pugging , which was used to deaden sound, insulate, and resist the spread of fire.
In platform framing , the joists may be connected to the rim joist with toenailing or by using a joist hanger . [ 5 ] | https://en.wikipedia.org/wiki/Joist |
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