Radioactive decay Hall of Fame-Part I

Michael F. Fifty'Annunziata , in Radioactivity, 2007

DEMOCRITUS (c.460–c.370 B.C.)

Democritus was a Greek philosopher born in Abdera in the n of Greece. Democritus was a pupil of Leucippus, who proposed the atomic theory of affair. There is little documentation on the philosophy of Leucippus; nevertheless, information technology was Democritus, who elaborated extensive works on his theories on the atomic structure of the physical world, of the universe, and the void of space. Although Democritus was a philosopher, he is included here among the list of great pioneers of physics and chemistry of the 19th and 20th centuries, because many of his teachings on the structure of matter were demonstrated finally by scientists over 2000 years after his death.

Democritus taught the theory of atomism, which held the conventionalities that indivisible and indestructible atoms are the basic components of all affair in the universe. Thus the word atom is derived from the Greek atomos meaning indivisible. It was not until 20 centuries after Democritus did Rutherford, Bohr, Soddy, and others demonstrate the atom to exist the smallest unit of an element consisting of a positively charged nucleus surrounded by electrons equal to the number of protons in the nucleus. Modern science has demonstrated that atoms remain undivided in affair (in accord with the early on philosophical teachings of Democritus) or in chemical reactions with the exception of a limited removal, commutation, or transfer of electrons. The atom is as well the basic unit of elements and is the source of nuclear free energy. The postage stamp stamp illustrated here was issued by Greece in 1961 to commemorate Democritus' teachings of atomism and the evolution of peaceful applications of atomic energy in the world.

Democritus was not lonely in the teaching of atomism, only his writings on this philosophy were most extensive. He held that atoms were the tiniest of particles, too minor to be perceived past the senses, of which all affair was composed, and that the atoms differed in size, shape, and mass. He also argued that atoms were in constant motion and could coagulate to course the larger bodies of matter that we can see, experience, and gustation. The backdrop of matter that we tin perceive with the senses such every bit color, gustation, and hardness were the effect of the interactions of atoms that constituted a given substance and the interactions of atoms with our body. For instance, the gustation of a substance would be the result of the interactions of atoms with the atoms of our tongue. Democritus also held to the conventionalities of the beingness of the "void" or empty space to which atoms or thing can movement into. He argued that the lights of the Milky Mode were the lights of afar stars, and that at that place existed other worlds, some with suns and moons, and others without. Likewise there would be other worlds with animal life, plants, and water and others without.

Much of Democritus' philosophy of atomism was demonstrated by modern science to exist true. In honor of Democritus the national institution dedicated to research on peaceful applications of atomic energy for development in Greece is named the Democritus Nuclear Inquiry Center. For additional reading on one of the greatest philosopher–scientists from artifact see Taylor's book The Atomists (1999).

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Accommodation of the Rare Earths in the Periodic Table

Pieter Thyssen , Koen Binnemans , in Handbook on the Physics and Chemical science of Rare Earths, 2011

6 Seaborg's Actinide Concept

Although Bohr considered thorium, protactinium, and uranium as members of a second series of rare earths, the majority of chemists remained convinced that these elements were homologues of hafnium, tantalum and tungsten, for a time later on Bohr had formulated his atomic theory. The reason for the delay of acceptance of a second rare-earth series was mainly due the fact that the highest valence states of thorium (+  Iv), protactinium (+   V) and uranium (+   Half-dozen) suggested that these elements were transition metals. Moreover, with the exception of thorium and cerium, at that place are, as well the similarities in electronic configuration, merely few similarities in chemic properties between the early actinide elements and the lanthanides. The chemical properties of uranium seem to differ very much from those of neodymium, whereas on the other hand there are hit similarities between uranium and the elements of group 5 (Cr, Mo, W). For instance, uranium and tungsten both form hexachlorides (UCl6 and WClhalf-dozen). Uranium forms the ion U2O7 2− and the compound UO2Cl2, while chromium forms Cr2O7 ii− and CrOiiClii. Nevertheless, 1 should note that the dissimilarities between uranium and neodymium are simply evident when hexavalent uranium (the well-nigh mutual oxidation state for uranium) and trivalent neodymium (the about common oxidation state for neodymium) are compared. Uranium(III) on one mitt, shows many similarities with neodymium(Iii), whereas on the other manus, uranium(Four) resembles thorium(Iv) and cerium(Four). Another bespeak of confusion was the very small energy differences betwixt the 5f- and 6d-beat, even in the range of the chemic binding free energy, so that it was hard to predict when the 5f-beat started to exist filled. Information technology was assumed that in thorium, protactinium, and uranium the 6d-shell was existence filled. Goldschmidt (1924) predicted that the transuranium elements up to element 96 would be platinum grouping elements. Nevertheless, several researchers believed in the existence of a 2d series of rare earths, even before the introduction of Bohr'south atomic theory in 1922. As early equally 1892, Bassett considered thorium and uranium to be analogous to cerium and praseodymium, respectively (Bassett, 1892). It should be noted that he preferred the order {Ce, Nd, Pr} rather than {Ce, Pr, Nd} for the lanthanides. Werner considered thorium as an analogue of cerium and uranium every bit an analogue of europium. Both authors reserved open up spaces in their periodic tables for other members of the second rare earths serial that were nevertheless undiscovered at that fourth dimension.

In 1926, Goldschmidt demonstrated the analogies between the elements {Th, Pa, U} and the lanthanides on the basis of the observation that the volumes of Thiv+ and U4+ showed the same contractions as the ions of the lanthanide series. Hit early examples of periodic tables in which actinium, thorium, protactinium, and uranium are considered as homologues of the rare earths lanthanum, cerium, praseodymium, and neodymium are the circular organisation and left-step table of Charles Janet (Janet, 1929).

Seaborg (1944, 1945) noticed that whereas thorium, protactinium, and uranium showed similarities in chemical behavior with zirconium, tantalum, and tungsten, respectively, neptunium and plutonium did not show such similarities with rhenium and osmium, or with technetium and ruthenium. For instance, in contrast to the volatiles osmium tetroxide and ruthenium tetroxide, there exists no volatile plutonium tetroxide. On the other hand, the chemical properties of neptunium and plutonium are very like to those of thorium and uranium. These four elements accept a stable +   4 oxidation state. ThOii, UOii, NpO2, and PuO2 are isomorphous and in that location is a steady decrease of the metal ion radius when going from Th4+ to Pu4+. Other evidence was based on magnetic susceptibility data, on the assimilation spectra of the ions in aqueous solution and in crystals, on the spectra of the gaseous atoms, and on additional crystallographic and chemical data. These observations fabricated Seaborg suggest the being of a second rare-globe series that begins with actinium, in the same sense equally that the lanthanide serial begins with lanthanum. He termed this 2d rare-earth series the "actinide serial.≥ The actinide elements do not tend to occupy the 6d orbital, but there is a gradual filling of the 5f shell over the actinide series. Although Seaborg assumed that thorium would be the starting time element at which the 5f orbital becomes occupied, he also considered the possibility that thorium and protactinium do not have 5f electrons, and that uranium has three 5f electrons. The actinide concept has every bit a outcome that +   III is a characteristic oxidation state for the actinides. Nonetheless, a striking difference between the lanthanide and actinide series is the being of oxidation states higher than +   Four in the actinide series (+   5 and +   VI). This is an indication that the 5f electrons are less tightly bonded than the 4f electrons. Seaborg (1949) introduced the form of the periodic table with which so many chemists are familiar with: i that considers the lanthanides and actinides as footnotes of the master body of the periodic table. A detailed account of the evolution of the actinide concept tin can be constitute in Chapter 118 in this Handbook (Seaborg, 1994).

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František Wald (1861–1930)

Klaus Ruthenberg , in Philosophy of Chemistry, 2012

Publisher Summary

The Czech chemist František Wald (1861–1930) was professor of physicochemistry and metallurgy in the Czech Technical University of Prague from 1908 until the twelvemonth of his expiry. He developed a theory of substances based on the concept of stage in response to his critique of diminutive theories inspired in large part by Ernst Mach. Although František Wald left out of account topics which would, peradventure, be appropriate for a "complete" theory and philosophy of chemistry (such as an business relationship of the character of processes, the relation between fourth dimension and potentiality, the predictive power of certain, even "metaphysical" theoretical concepts, the periodicity of elements, and so on), his approach is original and highly suggestive. He gave intriguing and substantial pointers to how the theoretical gap between the existing, positive knowledge nearly stuff and the phenomenalist, operational description of the path leading to that knowledge might be airtight.

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Prehistory of the Philosophy of Chemistry

Jaap van Brakel , in Philosophy of Chemical science, 2012

5 Ostwald, Cassirer, Paneth

In his anti-atomism, philosopher-chemist Ostwald aimed, first, to distinguish between what is given in experience and what is postulated past the mind: nothing compels us to assert that mercury oxide "contains" mercury and oxygen. Second, he aimed to show that energy is the almost full general concept of the physical sciences. 23

In his Faraday lecture of 1904 he still argued vehemently against the atomic theory and, acknowledging his debt to Franz Wald, 24 stressed that the deduction of the laws governing the nature of substances must kickoff from the conception of "phase," a concept far more general than that of substance. Ostwald was ane of the first physical chemists to give reasonably precise empirical (macroscopic, thermodynamic) definitions of chemic substances. In his terminology, if the properties of 2 circumstantial phases remain invariant during a phase change, the system is called hylotropic. If information technology is hylotropic over a range of temperatures as the pressure varies, it is a pure chemical substance. If it is not, it is a mixture. If it is hylotropic over all pressures and temperatures except the nigh extreme ones, it is a simple substance.

In 1907, while addressing metamerism, polymerism, and the role of valence in construction theory, 25 he acknowledges that when compared with "structure theory," his account in terms of differences in energy content "predicts, however, nothing whatever about the chemical reactions which are to be expected." He further acknowledges "the spatial organization of elements" to be "a very important aid." When the results of the experiments of Thomson on ions in the gas phase and Perrin on Brownian motion became bachelor Ostwald finally surrendered in November 1908: 26

I have convinced myself that a short while ago we arrived at the possession of experimental proof for the discrete or particulate [körnige] nature of substances [Stoffe], which the atomic hypothesis has vainly sought for a hundred years, even a thousand years.

Referring to publications by Duhem, Ostwald, and Meyer, the neo-Kantian Ernst Cassirer included 17 pages of his Substanzbegriff und Funktionsbegrif (1910) on chemical concepts. Cassirer associated the progress of science with the change from "purely empirical" descriptions of their subject matter, toward the rational stage of "constructive concepts" and wrote: "The conceptual construction of exact natural scientific discipline is incomplete on the logical side as long as information technology does not take into consideration the central concepts of chemical science" (203). Constructive concepts (which lend themselves to mathematical treatment) were realised in theoretical physics from the very beginning (Galileo, Newton), only were only slowly adult in chemistry, the first examples being Richter'south police force of definite proportions, Dalton's law of multiple proportions, Gibbs'south phase rule, the chemic atom characterised by diminutive number, and the theory of composite radicals. Similar many earlier him Cassirer stressed the relational aspect of chemical concepts and argued that the concept of a (chemical) atom is (since Dalton'south law of multiple proportions) a relational, regulative ideal concept, "a mere relative resting point." The concept of the cantlet is (merely) a mediator; therefore, "we may abstract from all metaphysical assertions regarding the existence of atoms" (208).

The pharmacist Paneth, already cited twice, is of importance for the philosophy of chemical science because of his engagement in the debate with Fajans and von Hevesy concerning chemical identity in view of the discovery of isotopes [van der Vet, 1979] and because of a thoroughly researched lecture he gave in 1931. 27 It addresses the familiar question how "elements" persist in compounds. Co-ordinate to Paneth the credible contradictions which arise can be dissolved by distinguishing conspicuously the double meaning or dissimilar aspects of the chemical concept of chemical element, which are divers referring to i some other. The Grundstoff or basic substance is "the indestructible stuff present in compounds and simple substances"; the einfacher Stoff or simple substance is "that form of occurrence in which an isolated basic substance uncombined with any other appears to our senses" (129-30, emphasis original). The latter is a chemical substance like others, except that it cannot be decomposed (further) by chemical ways. 28 The former provides the basis for the systematic ordering of the elements in the periodic system. Although the atomic theory contributes enormously to our understanding, "the concept of basic substance as such does non in itself contain any idea of atomism", as Lavoisier best-selling (133). Paneth extended his distinction to the radicals of organic chemistry (normally unobservable), compounds of higher club (such as SO3.H2O), also as (forms of occurrence of) simple substances (because of different phases, allotropy, etc.). 29

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Atmospheric Thermodynamics

John M. Wallace , Peter V. Hobbs , in Atmospheric Scientific discipline (Second Edition), 2006

The kinetic theory of gases pictures a gas as an assemblage of numerous identical particles (atoms or molecules) 3 4 5 6 that motility in random directions with a variety of speeds. The particles are causeless to be very small-scale compared to their average separation and are perfectly elastic (i.e., if one of the particles hits another, or a fixed wall, it rebounds, on boilerplate, with the same speed that it possessed just prior to the collision). It is shown in the kinetic theory of gases that the mean kinetic free energy of the particles is proportional to the temperature in degrees kelvin of the gas.

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Nuclear Physics

Christopher R. Gould , ... Philip J. Siemens , in Encyclopedia of Physical Science and Technology (Third Edition), 2003

I Twentieth-Century History

The foundations of both modern nuclear physics and modernistic atomic physics were established past Ernest (Lord) Rutherford through a series of historic experiments first published in 1911. He used blastoff particles from naturally radioactive emitters as projectiles to bombard a variety of targets, and he detected the scattered alpha particles past visually observing scintillations on a phosphorescent screen. From the distribution of scattered particles, he was able to demonstrate that the interaction of alpha particles with atoms obeyed Coulomb'due south changed-square law downward to distances on the social club of ten−xiii  m   =   100 fm (one fm   =   10−fifteen  m).

The flick that emerged from Rutherford'southward experiments was that of an atom consisting of a massive core—the nucleus—of positive electric charge Ze, where –east is the accuse on the electron and Z is the atomic number. The nucleus is surrounded by a negatively charged electron gas. Earlier diminutive theories cruel, nearly notably J. J. Thomson's model of electrons embedded in a positively charged "jelly." In 1913, Niels Bohr announced his atomic theory of electrons circling the nucleus in quantized planetary orbits. Further studies in diminutive physics led to the discovery (invention) of quantum mechanics past Werner Heisenberg (1925) and Erwin Schrödinger (1926).

The discovery of the neutron by James Chadwick in 1932 antiseptic both the trouble of isotopic composition and the connection between atomic weight A and nuclear spin. With protons and neutrons at present known to exist the edifice blocks of nuclei, the study of nuclear construction was launched.

In 1935, Hideki Yukawa postulated the beingness of a new, intermediate-weight elementary particle, which he chosen the mesotron, to act as the amanuensis to demark neutrons and protons together in the nucleus. Some confusion ensued when Carl Anderson and Seth Neddermeyer discovered a candidate particle in 1938 that did not seem to interact strongly with nuclei. The problem was resolved in 1947 by Cecil Powell and collaborators who identified two particles, the mu and the pi mesons, the latter being the Yukawa mesotron (at present called the pion); the mu meson, or muon, is the Anderson–Neddermeyer particle. This was a remarkable triumph of speculative theoretical consecration. It also completed the first stage in the microscopic clarification of nuclear structure. Subsequently, a host of simple particles has been institute, many of which play important roles in nuclear physics. (Meet Department VII.B.)

The discovery of fission past Otto Hahn and Fritz Strassmann in 1939 led to the development of the atomic (more properly nuclear) bomb during World War II and the attendant evolution of fission reactors for electrical ability generation. The fusion process, which is the machinery by which the sun and stars generate their free energy, was the basis for development of the hydrogen bomb in the 1950s, and there has been intense research during the subsequent decades to harness thermonuclear fusion as a power source. At the same time, nuclear physics and chemistry take provided radioactive isotopes, radioactive and stable isotope identification techniques, nuclear magnetic resonance, etc. for medical diagnosis and treatment, geological and archaeological dating, tracing of water and atmospheric flow patterns, planetary and solar system histories, and numerous other applications.

At present, much involvement is being concentrated on nuclear substructure, namely, the constituents of the protons, neutrons, and other particles previously considered to be elementary. The subparticles are chosen quarks; the proton and the neutron each contain three quarks.

Effigy 1 summarizes, from top to bottom, the historical evolution of nuclear physics and nuclear phenomena studied with particle accelerations. At the lowest energies (longest length scales), the collective modes of nuclei—rotations and vibrations—are axiomatic. As the energy increases (shorter length scales) the presence of individual nucleons in vanquish model orbits is revealed, the nucleons themselves interacting via the exchange of mesons. At the highest energies (shortest length scales), the quark and gluon structure of the nucleons is observed. The theory of nucleons interacting via the exchange of mesons is called breakthrough hadrodynamics (QHD). The theory of quark–gluon interactions is called quantum chromodynamics (QCD). Linking these descriptions of nuclear phenomena is a major challenge for theoretical physics.

Effigy 1. Structure of nuclei revealed past projectiles of low to high free energy (from top to lesser), probing shorter length scales equally the energy increases.

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The First Constabulary of Thermodynamics

In Applied Chemical Thermodynamics for Geoscientists, 2013

C Joule's experiments on the mechanical equivalent of heat

James Joule was one of the most remarkable apprentice scientists of the 19th century (encounter sidebar). Starting about 1840, Joule began a series of ingenious experiments in which different types of work were converted into oestrus and the proportionality betwixt the two was measured. In other words, Joule measured the mechanical equivalent of heat given past the ratio of work done to the heat produced. These experiments included the electric heating of a wire coil immersed in water, the heating produced by compressing air into a cylinder that was immersed in water, and the heating produced by

JAMES PRESCOTT JOULE (1818–1889)

Joule was mayhap the greatest amateur scientist of the 19th century. He was the son of a wealthy Manchester, England, brewer and conducted his experiments in the family brewery. John Dalton, who developed the atomic theory and Dalton's law, educated Joule and his blood brother. Joule published his starting time scientific newspaper nigh electric motors at the age of 19. His research on electricity led to Joule's law ( q

=

I ii Rt), which gives the amount of heat generated by a electric current I flowing through a wire with resistance R for fourth dimension t.

His electrical inquiry led Joule to study the transformation of work into heat. He constitute that a given corporeality of work generates the aforementioned amount of heat, regardless of how the work is done. Joule measured the mechanical equivalent of heat to exist 0.241 cal/J, which is quite close to the modern accepted value of 0.239 cal/J. His experimental piece of work established the start law of thermodynamics. Joule's free expansion experiment and his later on piece of work on gas expansion with William Thomson (Kelvin), known as the Joule–Thomson (Kelvin) effect, laid the foundation for much of modern refrigeration technology. Joule'southward scientific papers on these and other topics are remarkable for their insights into the basic laws of nature. They are also entertaining reading.

Perhaps the most remarkable thing about Joule was his talent for making very precise measurements with rudimentary equipment. His experimental accuracy is legendary. His colleague, Kelvin, said of him, "His boldness in making such large conclusions from such very pocket-size observational furnishings is almost equally noteworthy and beauteous as his skill in extorting accurateness from them."

paddle wheels stirring water, sperm whale oil, or mercury. A summary of Joule'due south results is given in Tabular array 3-i; you lot can see that some of the experiments Joule did were more accurate than others. All these information, however, led Joule to conclude that the amount of heat produced in his experiments depended just on the amount of piece of work done—not on how the work was washed or on the type of piece of work.

Table three-ane. Joule's Determinations of the Mechanical Equivalent of Heat

Type of Work Work (ft-lb.) a
Turning paddle wheels in water (1849) 772.7
Turning paddle wheels in mercury (1849) 774.one
Rubbing together ii iron blocks immersed in mercury (1849) 775
Turning paddle wheels in water (1845, 1847) 781.5
Turning paddle wheels in sperm whale oil (1845, 1847) 782.1
Turning paddle wheels in mercury (1845, 1847) 787.six
Compressing gas into a cylinder immersed in water (1843) 798
Electrical current through a wire coil immersed in water (1843) 838
Mean value (±one sigma) for the corporeality of work done 789±22
The mod experimental value is equal to 777.72
The defined thermochemical calorie gives 777.65
a
From Joule (1850), "On the Mechanical Equivalent of Heat," Phil. Trans. Roy. Soc. London 140, 61, and references therein. The amount of work washed is the number of human foot pounds needed to raise the temperature of one pound of water by 1°F—in other words, foot pounds per BTU.

Joule'due south most famous and probably most authentic experiments were his paddle wheel experiments washed in 1849. Effigy 3-2 is a schematic diagram of these experiments in which falling weights were used to plow paddle wheels inside a tank of h2o. The tank contained stationary metal vanes to prevent rotation of water in the tank and to increase the frictional heating. The paddle wheels were positioned between the vanes; for instance, from bottom to tiptop the arrangement would be vane, paddle bike, vane, paddle bike, then on. This entire apparatus was within an insulated wood container (not shown) to prevent heat exchange with the surroundings. A system such as Joule's water tank, which is thermally insulated from the surroundings, is called an adiabatic system. The give-and-take adiabatic is derived from the Greek word adiabatos, which means impassable. Thus, an adiabatic wall is impassable to heat, an adiabatic system is perfectly thermally insulated from its surround, and an adiabatic process has no rut period betwixt the system and its surroundings.

FIGURE three-2. A schematic diagram of Joule's paddle cycle experiment. When the handle was released, the weights savage, unwinding the string and turning the paddles. This process was repeated several times and the resulting temperature increase of the water was measured.

The work done in Joule'due south experiments was calculated by multiplying the mass of the weights by the local acceleration of gravity and by the total altitude they fell. The heat produced was calculated by measuring the temperature increase of the known mass of water contained in the insulated tank. Based on his paddle wheel experiments with water, Joule concluded that "the quantity of rut capable of increasing the temperature of a pound of water (weighed in vacuo, and taken at between 55° and 60°) by one°Fahr. requires for its development the expenditure of a mechanical forcefulness represented by the fall of 772 lb. through the space of one human foot." Equally shown in Table 3-1, Joule computed like values for the amount of work needed to estrus one pound of water from his other experiments.

Case 3-ii. Using the free energy conversion factors given in Table 3-2, nosotros can convert Joule'due south results into more than user-friendly units. Joule measured the work done in human foot pounds (ft-lb) and gives the mechanical equivalent of estrus in terms of British thermal units (BTU), which is the amount of heat needed to increment the temperature of one pound of water by 1°F. He found that one BTU was equivalent to 772 ft-lb. From Tabular array iii-ii, we encounter that 1 BTU   =   252.0 cal and that 772 ft-lb = (1.356)(772)   =   1046.8 J. Equating the two expressions we find that

Table 3-ii. Free energy Conversion Factors a

J cal erg eV liter-bar
1 J   = 1 0.239006 x7 1.0364269   ×   10−five 10−ii
1 cal = 4.184 1 4.184   ×   107 4.336410   ×   x−five 4.184   ×   10−2
1 erg = ten−7 2.390057   ×   10−8 1 one.0364269   ×   ten−12 x−9
one eV = 96,485.3415 23,060.5501 nine.648534   ×   1011 1 964.853415
1 L bar = 100.000 23.90057 10ix ane.0364269   ×   10−3 1
one L atm = 101.325 24.2173 one.01325   ×   109 1.0501595   ×   10−3 1.01325
1 BTU = one,054.35 251.9957 one.05435   ×   1010 1.0927567   ×   10−2 10.5435
1 KWH a = iii.600   ×   xhalf dozen 860,420.65 3.600   ×   1013 37.311367 iii.600   ×   104
1 ft-lb = 1.355818 0.324048 1.355818   ×   107 1.4052062   ×   10−5 1.355818   ×   10−2
one cm−ane = 11.96266 2.85914 1.196266   ×   10viii one.2398422   ×   10−4 0.1196266
liter-atm BTU KWH ft-lb cm−1
1 J = ix.8692327   ×   x−3 9.484517   ×   10−four two.77778   ×   10−7 0.737562 viii.359345   ×   ten−2
1 cal = four.1292795   ×   ten−2 3.968322   ×   10−three 1.162222   ×   x−vi 3.085960 0.349756
1 erg = nine.869232   ×   ten−ten 9.48452   ×   10−xi two.77778   ×   ten−14 7.375621   ×   10−viii eight.359345   ×   10−9
1 eV = 952.23628 91.511682 ii.680148   ×   10−2 71,163.9331 8,065.5424
one L bar = 0.986923 9.484517   ×   10−ii 2.77778   ×   x−v 73.75621 viii.359345
1 L atm = one 9.610186   ×   10−2 two.814586   ×   10−5 74.73348 viii.470106
1 BTU = 10.405625 1 2.928750   ×   10−4 777.6486 88.136752
one KWH = 35,529.2376 three,414.426 1 two.655224   ×   tenhalf-dozen 3.009364   ×   10five
i ft-lb = i.338088   ×   ten−2 1.285928   ×   10−iii iii.766161   ×   10−7 1 0.113338
1 cm−1 = 0.1180623 i.134595   ×   ten−two 3.322961   ×   ten−vi 8.823205 one
a
eV   =   electron volts per mole; KWH   =   kilowatt hr; cm−1  =   cm−one per mole

(3-viii) 1 BTU = 252.0 cal = 1046.8 J = 772 ft-lb

In other words, Joule's effect for the mechanical equivalent of oestrus is equal to 252.0 cal/1046.eight J   =   0.241 cal J−1, which is within i% of the modern value of 0.239 cal J−1.

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Friedrich Wilhelm Ostwald (1853–1932)

Robert J. Deltete , in Philosophy of Chemistry, 2012

2 Intellectual Odyssey

Ostwald's general philosophical development may be divided into four overlapping, but reasonably distinct, periods. During the beginning of these, which lasted until effectually 1890, he was an clear, if increasingly cautious, defender of much that was basic to the mechanical world-view. Ostwald was not always an opponent of the atomic theory in chemistry, or of kinetic and molecular theories generally. On the opposite, he enthusiastically endorsed such views, in works through the early on 1880's, and remained a qualified supporter of them until he began seriously to write on energetics almost ten years afterwards (meet [Görs, 1999; Deltete, 2007a]). This is clearly visible in his development — rather naive at get-go, but later more circumspect — of atomic and kinetic theories in a multifariousness of essays and textbooks. And information technology is evident, as well, in his defense of, and contributions to, the theories of Arrhenius and van 't Hoff, both of which developed particulate views of substances in solution. With certain exceptions, Ostwald no longer offered realistic interpretations of such theories after about 1885, but he defended their heuristic value until the end of the decade.

At the same time, though, Ostwald too began to appreciate more than than he had previously the heuristic advantages of phenomenological thermodynamics — its nifty success in deriving one-time results clearly and concisely, and in predicting new ones, without the complications and uncertainties associated with molecular and mechanical detours [1887a; 1887b; 1891; 1892]. This was initially evident to him in areas of physical chemical science to which he had himself already made important contributions, but he soon recognized the ability of thermodynamic reasoning in other areas as well. The key to that power, he thought, was the attention given in thermodynamics to energy and its transformations. Ostwald gradually came to believe that while theories based on micro-mechanical hypotheses had fabricated fiddling progress with many problems, non-mechanistic, energy-based approaches had been dramatically successful. Those successes encouraged him to study the various forms of energy more than carefully for himself (see Deltete 1995b and 2007a).

The 2nd catamenia, which partially overlaps the first, extends from the late 1880's until merely afterward the turn of the century. It is marked by Ostwald's rejection of atomism and mechanism — in any of their forms — and by his efforts to provide a comprehensive energetic alternative. In the early years of this period, Ostwald began to dubiousness even the heuristic value of molecular and mechanical theories. He questioned the complexity of their mathematical evolution and their reliance on, as he saw information technology, capricious and unjustifiable hypotheses. Increasingly, he viewed many such theories as irresponsibly speculative and unscientific. Afterward the mid-1890's, in fact, Ostwald'south mental attitude toward even well-established mechanical theories was so hostile that he sometimes denied that they had always been of any value at all. Several full general works from those years consist of little more than than sweeping condemnations of the mechanical world-view (due east.k., [1895b]).

Ostwald's views on energy during this period develop in two fairly singled-out stages. In writings from 1887 to 1890, he was concerned primarily to establish the importance of energy alongside matter every bit central to a progressive natural science [1887a; 1887b; Deltete, 2007a]. There he insisted on the importance of energy considerations, not simply for chemistry, but for other sciences as well. The emphasis in these works gradually shifts from chemical energy and its transformations to the creation of a general theory of energy. Increasingly, he saw any success of studies deploying quantities of free energy as reason for thinking that a theory of free energy could unify natural science. Ostwald'southward first efforts at constructing such a theory were tentative and incomplete (e.chiliad., [1889]), merely he became bolder every bit he gained confidence in his approach and its credible results.

In 1891, Ostwald began to affirm first the priority, and then the absolute supremacy of free energy — conceptually, methodologically and ontologically. Though he had claimed reality and substantiality for free energy every bit early every bit 1887, his ambitions for information technology grew as his idea progressed, and by mid-decade he was prepared to assert, unequivocally, that energy was the but reality. The same years witnessed Ostwald's nigh persistent attempts to construct a consequent and coherent science of energetics. A variety of factors influenced those efforts: discussions with colleagues and students; continued reflection on the conceptual structure of thermodynamics; written report of earlier energetic writings, specially Georg Helm'south; encouragement from Helm, Boltzmann and others to limited his thoughts on energy in a systematic form; and a decisive encounter with the thermodynamic writings of Willard Gibbs (come across [Deltete, 1995a; 1995b]). In a serial of works, published between 1891 and 1895, Ostwald sought to show how the basic results of mechanics, thermodynamics and chemistry could all exist derived from energetic first principles [1891; 1892; 1893a; 1893b; 1895a]. His early declarations of success were mostly tentative and carefully worded, but those of the tardily l890's became increasingly emphatic. By the cease of the decade, he was convinced that while private issues nonetheless remained, the basic theoretical framework for their solution had been firmly established. Merely past then such residual problems were besides of less interest to Ostwald than another ambitious project which had captured his attention.

In what follows, I volition focus on these two periods in Ostwald's development, during which his efforts in behalf of energetics had its basis in concrete science. A third period, which lasted from around the turn of the century until the beginning of the Offset World War, had as its center a more broadly philosophical projection. Those years — most of them afterwards he had resigned his chair at Leipzig — were characterized past his attempt to bear witness that the sciences of life and the listen, such as biology and psychology, were as well embraced by energetics. At the same time, even so, the character and non just the content of his writings inverse. Ostwald had been interested in philosophical problems (in scientific methodology, for example) from his student days, simply beginning in the late 1890's such problems began to dominate his thoughts. Increasingly, he relied on full general philosophical arguments to defend energetics, and global references to "Monismus" and "Weltanschauung" replaced detailed discussions of chemical affinity and the forms of energy (e.g., [1902; 1908]). Nearly witnesses thought that the first decade of this century marked the demise of energetics as a serious scientific proposal and its continuation just as a rather vague philosophical movement (e.chiliad., [Arrhenius, 1923; Nernst, 1932]).

No attempt will be made hither to discuss the works of a fourth flow (which includes the development of his novel theory of colors) that completes Ostwald's intellectual odyssey, except to say that from but before the beginning of the WWI until the end of his life, Ostwald tried to formulate global social and political theories based on the principles of energetics (e.g. [1911; 1912; Deltete, 2008a]). There is much to admire in his efforts (Ostwald was internationalist, anti-war, and pro-environment), but they have at best just a vague connexion to the energetic theory he had proposed 2 decades earlier.

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Solar Radiation, Black Bodies, Rut Upkeep, and Radiations Residual

Grand.B. Kirkham , in Principles of Soil and Constitute Water Relations (2d Edition), 2014

25.fifteen Appendix: Biography of Ludwig Boltzmann

Ludwig Boltzmann (1844–1906), Austrian physicist, fabricated of import contributions to many branches of physics. His greatest achievements were the development of statistical mechanics and the statistical caption of the second law of thermodynamics. He was born in Vienna on February twenty, 1844, and studied at the university there, receiving his doctorate in 1866. He held professorships in mathematics (Vienna, 1873–1876), experimental physics (Graz, 1876–1889), and theoretical physics (Graz, 1869–1873; Munich, 1889–1893; Vienna, 1894–1900; Leipzig, 1900–1902; Vienna, 1902–1906). Despite his several professorships, theoretical physics was his real vocation (Klein, 1971).

In 1905, when he was professor of theoretical physics at the University of Vienna, Boltzmann was invited to give a class of lectures in the summer session at the University of California in Berkeley. His recollections of that summertime survive in his popular essay, "Reise eines deutschen Professors ins Eldorado." An abridged translation is presented in Physics Today (Boltzmann, 1905). Boltzmann's great sense of humour is axiomatic in this writing.

When Boltzmann began his scientific work, he attacked the problem, until and so unconsidered, of explaining the second constabulary of thermodynamics on the ground of the atomic theory of matter. In a series of papers published during the 1870s, Boltzmann showed that the second law could be understood by combining the laws of mechanics, practical to the motions of the atoms, with the theory of probability. In this fashion, he fabricated clear that the second law is an essentially statistical law and that a system will approach a land of thermodynamic equilibrium, because the equilibrium land is overwhelmingly the most probable state. The entropy role of thermodynamics, whose behavior shows the trend to equilibrium and whose maximum value characterizes the equilibrium country, is itself a measure of the probability of the macroscopic state. (The equation relating entropy and probability is engraved on the monument at Boltzmann's grave in Vienna.) He built much of the structure of statistical mechanics, a construction afterward elaborated past the U.South. mathematical physicist Josiah Willard Gibbs (1839–1903) ( Klein, 1971).

Apart from Boltzmann'south work on statistical mechanics, he made extensive calculations in the kinetic theory of gases. He was also i of the offset Europeans to recognize and to expound on the importance of James Clerk Maxwell'south (1831–1879; Scottish physicist) theory of electromagnetism, a subject on which he published a two-volume treatise. Boltzmann also derived, using thermodynamics, Stefan'due south police for blackness-body radiation, a derivation that Hendrik Antoon Lorentz (1853–1928, Dutch physicist who got the Nobel Prize in physics in 1902) called "a truthful pearl of theoretical physics" (Klein, 1971).

Boltzmann's work in statistical mechanics was strongly attacked by Wilhelm Ostwald (1853–1932; High german chemist who received the Nobel Prize in chemistry in 1909) and the energeticists who did not believe in atoms and wanted to base all of physical science on energy considerations just. Boltzmann also suffered from misunderstandings, on the role of others, nearly his ideas on the nature of irreversibility. They did non fully grasp the statistical nature of his reasoning. He was fully justified against both sets of opponents by the discoveries in diminutive physics, which began shortly earlier 1900 and by the fluctuation phenomena, such as Brownian motility, which could be understood only by statistical mechanics (Klein, 1971). In 1905, Einstein explained Brownian motion (Isaacson, 2009; pp. 25, 27) past means of Boltzmann'due south ideas (Cercignani, 1998; p. 102), simply Boltzmann died apparently earlier he knew about Einstein's confirmation of his work. Cercignani (1998) gives an in-depth give-and-take of the scientific world in which Boltzmann lived.

Depressed past the criticism of his piece of work, Boltzmann took his ain life by hanging on September v, 1906, at Duino, near Trieste, Italy (Klein, 1971).

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Development, Theory of

Gregory C. Mayer , Catherine Fifty. Craig , in Encyclopedia of Biodiversity (Second Edition), 2013

Introduction

What a Theory is

Before embarking on an exposition of the theory of development, it is necessary to clear up a common misunderstanding that arises from a confusion of the colloquial and technical meanings of the discussion "theory." In everyday speech, "theory" is often taken to mean a approximate, an hypothesis, or a speculation – something opposed to the more surely known "facts." In the context in which the word is used in the phrase "evolutionary theory," however, and indeed in much of scientific discipline, information technology signifies a serial of interconnected high-level generalizations based on a big torso of testify. Thus, one speaks of "atomic theory," "quantum theory," or the "germ theory of disease." Far from indicating that these sets of continued propositions are mere speculations, information technology indicates that they are well supported past a considerable corpus of data.

All scientific theories, of course, are provisional (as indeed are all scientific "facts") and subject to revision in the low-cal of further data. It is e'er salutary to bear this in mind, and also that some of the ideas and findings are more probable to be subject to revision than others. But information technology is important to know that the give-and-take "theory" does not division scientific propositions into those more or less likely to be revised. Rather, information technology attaches to some of the most well-supported propositions, equally in the examples just discussed. Information technology is in this sense that this article refers to the "theory of evolution."

What Evolution is

If "evolution" means "modify over fourth dimension," there are many things that evolve. Solar systems, for example, evolve. Stars condense, planets form, comets come and go, and stars age in predictable sequences. Languages also evolve. Within historical times, Latin has given rise to French, Castilian, Italian, and the other Romance languages, while contributing much vocabulary to the evolution of English. But the biological theory of evolution does non embrace cosmology or historical linguistics; rather information technology is restricted to organic evolution, that is, changes in living beings over time. This formulation is still too broad, since individual organisms grow and develop over time (i.east., have an ontogeny), but this is not evolution in the mod sense. The changes in life over time that business concern humans are those that persist beyond the lifetime of a single individual and are transmissible to offspring (i.e., are heritable). So organic evolution consists of changes in living beings that transcend a single generation, and which, in principle, can exist transmitted through an indefinite number of generations.

The theory of evolution, every bit considered here, is primarily concerned with the mechanisms of evolutionary change. The study of evolutionary mechanisms, or the causes of development, however, is but one of the two bully branches of evolutionary biological science (Futuyma, 1998). The other is the written report of the history of life – phylogeny in the wide sense. The biodiversity observed today, and in the fossil record of by times, is the product of evolutionary mechanisms in tandem with changes in environment and geography acting on organic beings over long periods of time. This history of life and its present condition and causes, of both item branches of the phylogenetic tree and biodiversity in general, are the bailiwick of the greater function of this Encyclopedia.

Genetics, ecology, and developmental biology are amidst the disciplines that contribute largely to the written report of evolutionary processes, whereas systematics and paleontology are amongst those that contribute to evolutionary history and the interpretation of the evolutionary chronicle (O'Hara, 1988). All these disciplines, however, collaborate in ways that do non allow a cracking separation of their contributions to the two sides of evolutionary biological science. Equally Dobzhansky (1973) noted, nothing in biological science makes sense unless it is studied in an evolutionary context, and all fields of biology provide insight into the processes of development and the history of life.

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