The First Half-Century

Although several other early studies were conducted using Supercritical Fluids (SFs), also termed at that time as dense gases , this field did not receive the attention it deserved during the first half century after its discovery. Even then, the small number of investigators dedicated to further explore the scientific and technological potential of supercritical fluids concentrated then efforts on industrial rather than analytical applications (9, 10). 

Ibid., 167 and A. N. Shimmin, The University of Leeds The First Half-Century (Cambridge ... 

Lewis published these ideas in his 1923 book Valence and the Structure of Atoms and Molecules, and they were widely taken up and developed in the U.S.A. and Europe, for example, by N. V. Sidgwick at Oxford, whose Electronic Theory of Valency appeared in 1927. The Nobel Prize in Chemistry was left unfilled in 1919, 1924 and 1933 for lack of candidates of suitable stature, and Lewis would have been an appropriate candidate for any of these years. In fact, he was nominated for a Nobel Prize by the inorganic chemist and historian of chemistry, J. R. Partington (1886-1965) at the University of London. For the first half-century after the award of the first Nobel Prize in Chemistry to van t Hoff in 1901, the chemistry prize went to those who had discovered or characterised new chemical elements, new physico-chemical principles, new chemical reactions, or had elucidated the structure and accomplished the synthesis of natural products. The first award for research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances went in 1954 to Linus Pauling at Caltech. 

Although both reliables and whimsicals will contribute during the transition to a fully developed hydrogen age, reliables will always dominate. And among reliables, I expect nuclear fission will be preeminent—at least during the first half-century of the fully developed hydrogen age. Thereafter, it gets harder to be sure. For example, by 2150 it is conceivable that... 

Blaustein SB (1993) Unemployment insurance in the United States The first half-century. 

Green and Rodgman (1373) reviewed presentations during the first half century (1947-1996) of the TCRC on the subject of the identification and quantitation of aldehydes and ketones in cigarette MSS and SSS as well as in ETS. 

True, F.W. (1913). A history on the first half-century of the National Academy of Sciences 1863-1913. National Academy of Sciences Washington DC. http //en.wikipedia.org/wiki/Julius Erasmus Hilgard P... 

To first order, the dispersion (a-a) interaction is independent of the structure in a condensed medium and should be approximately pairwise additive. Qualitatively, this is because the dispersion interaction results from a small perturbation of electronic motions so that many such perturbations can add without serious mutual interaction. Because of this simplification and its ubiquity in colloid and surface science, dispersion forces have received the most significant attention in the past half-century. The way dispersion forces lead to long-range interactions is discussed in Section VI-3 below. Before we present this discussion, it is useful to recast the key equations in cgs/esu units and SI units in Tables VI-2 and VI-3. 

In Chapter 1 we saw that a major achievement of the first half of the twentieth cen tury was the picture of atomic and molecular structure revealed by quantum mechan ICS In this the last chapter we examine the major achievement of the second half of that century—a molecular view of genetics based on the structure and biochemistry of nucleic acids... 

The earliest examples of analytical methods based on chemical kinetics, which date from the late nineteenth century, took advantage of the catalytic activity of enzymes. Typically, the enzyme was added to a solution containing a suitable substrate, and the reaction between the two was monitored for a fixed time. The enzyme s activity was determined by measuring the amount of substrate that had reacted. Enzymes also were used in procedures for the quantitative analysis of hydrogen peroxide and carbohydrates. The application of catalytic reactions continued in the first half of the twentieth century, and developments included the use of nonenzymatic catalysts, noncatalytic reactions, and differences in reaction rates when analyzing samples with several analytes. 

Galen, a physician whose views outUved him by about a thousand years, died about 200 AD. He beUeved that mercurials were toxic, and did not use any mercury compound therapeutically. However, as a result of Arabian influence, the therapeutic uses of mercury were slowly recognized by Western Europe. In the thirteenth century mercury ointments were prescribed for treating chronic diseases of the skin. Mercury and its compounds, such as mercurous chloride, mercuric oxide, mercuric chloride, and mercuric sulfide, were used widely from the fifteenth to the nineteenth centuries, and to some extent in the twentieth century. During the first half of the twentieth century, the primary therapeutic uses of mercury included bactericidal preparations, such as mercuric chloride, mercuric oxycyanide, and mercuric oxide and diuretics, such as aryl HgX (Novasural) and mercurated ahyl derivatives (14). 

Production. Commercial production of Hthopone started in the first half of the nineteenth century, and continued to grow until the middle of the twentieth century when titanium dioxide started to dominate the white, inorganic pigment market. Lithopone is prepared by combining barium sulfide and 2inc sulfate solutions at 50—60°C ... 

Unit Operations. The chemistries elaborated by all of these systems are described by seven unit operations (Fig. 5). The first six, the use of lime and carbon dioxide as clarification agents, were laid out during the first half of the twentieth century and only the appHcation technology has changed since, mainly from small batch processes designed to handle 1000 Hters in a few hours to continuous systems capable of processing up to 10,000 L/min. 

Pyrite is the most abundant of the metal sulfides. Eor many years, until the Erasch process was developed, pyrite was the main source of sulfur and, for much of the first half of the twentieth century, comprised over 50% of world sulfur production. Pyrite reserves are distributed throughout the world and known deposits have been mined in about 30 countries. Possibly the largest pyrite reserves in the world are located in southern Spain, Portugal, and the CIS. Large deposits are also in Canada, Cypms, Einland, Italy, Japan, Norway, South Africa, Sweden, Turkey, the United States, and Yugoslavia. However, the three main regional producers of pyrites continue to be Western Europe Eastern Europe, including the CIS and China. 

For many industrialized countries, efforts to improve the outdoor air quality have been under way for the majority of this century. In many locations around the world, significant improvements have taken place. Air quality in many major cities such as London, New York, and Chicago has improved from the conditions present in the first half of the twentieth century. Mechanisms and control programs are in place in the developed countries to continue the improvement of ambient air quality. Considerable effort and energy have been expended to characterize, evaluate, and control air pollution emissions to the atmosphere. 

All overview of the glycolytic pathway is presented in Figure 19.1. Most of the details of this pathway (the first metabolic pathway to be elucidated) were worked out in the first half of the 20th century by the German biochemists Otto Warburg, G. Embden, and O. Meyerhof. In fact, the sequence of reactions in Figure 19.1 is often referred to as the Embden-Meyerhof pathway. 

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