The Early Days

Despite the existence of an early paper by Ito et al. (1983), the first actual implementation of an MOEA is normally attributed to David Schaffer, who developed the Vector Evaluated Genetic Algorithm (VEGA) in the mid 1980s (Schaffer, 1985). 

Srinivas and Deb (1994) proposed the Nondominated Sorting Genetic Algorithm (NSGA) which is based on several layers of classifications of the individuals as suggested by Goldberg (1989). Before selection is performed, the population is ranked on the basis of nondomination all nondominated individuals are classified into one 

After the publication of the SPEA paper, most researchers in the field started to incorporate external populations in their MOEAs as their elitist mechanism. In 2001, a revised version of SPEA (called SPEA2) was introduced. SPEA2 has three main differences with respect to its predecessor (Zitzler et al, 2001) (1) it incorporates a fine-grained fitness assignment strategy which takes into account for each individual, the 

Claude Bernard (1813-1878) dedicated his life to the search for an understanding, in terms of physics and chemistry, of those processes by which we live, by which we become ill, by which we are healed, and by which we die. His research transformed medical science from its anatomical to a new foundation in physiology. 

In 1890, William James wrote, Chemical action must of course accompanybrain activity, but little is known of its exact nature. What would James think about today s molecular imaging of the brain  

Seymour Kety was the first to measure the blood flow to the brain of a human being, applying the Pick principle after injecting nitrous oxide (N2O), a diffusible gas, into a cerebral artery, and then measuring the difference in tracer concentrations in the arterial blood going to the brain and in venous blood coming from the brain. 

Arterial blood was sampled from the femoral artery to reflect cerebral arterial blood. Venous blood was sampled from the superior bulb of the internal jugular vein. After the subject had breathed nitrous oxide for 10 minutes, the concentrations in the brain and cerebral venous blood were close enough to equilibrium to allow calculation of brain NjO concentration from the measured cerebral venous concentration at that time and the relative solubility (i.e., partition coefficient) of N2O in brain and blood. 

In 1913, George Hevesy introduced the use of radioactive indicators when he used radioactive lead to track the movement of lead from the soil into plants and then back to the soil. He later extended these studies to living animals. In 1935, he showed how elements and molecules are taken up and released continually by living cells, a process called the dynamic state of body constituents. 

Based on X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), electron spin resonance (ESR), Mbssbauer, and extended X-ray absorption fine structure spectroscopy (EXAFS) , van Veen and collaborators concluded that the thermal treatment at temperatures where catalytic activity is maximum ( 500-600°C) does not lead to complete destruction of the macrocycles, but rather to a ligand modification which preserves the Me-N4 moiety intact. Furthermore, the stability of this catalytic site is improved because the reactive parts of the ligands are bound to the carbon support and thus are no longer susceptible to an oxidative attack. Thermal treatments at higher temperatures (up to 850°C) led to some decomposition of the Me-N4 moiety, and thus to a decrease of the catalytic activity, and to the reduction of some of the ions to their metallic state. 

On the other hand, based on pyrolysis mass spectrometry, pyrolysis gas chromatography, microanalysis and mainly Mossbauer spectroscopy , Yeager and his collaborators who were mainly working at high pyrolysis temperatures (800-850°C) disagreed with the previous school. They concluded that the decomposition of Me-N4 macrocycles starts at about 400-500°C. At 800°C, despite the fact that heat-treated samples retain more than 80% of the nitrogen atom content measured for the untreated 

A third school, led by Wiesener, proposed that the Co or Fe ions of the adsorbed N4 chelates promote the decomposition of the chelate upon thermal treatment followed by the formation, at high temperature, of a special form of carbon that would be the true catalyst. In this scenario the metal is only an intermediate and has no active role in the electroreduction of oxygen. In a later publication, they concluded that nitrogen is involved in the electrocatalytic active group on carbon. 

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STOIIP" s a term which normalises volumes of oil contained under high pressure and temperature in the subsurface to surface conditions (e.g. 1 bar, 15°C). In the early days of the industry this surface volume was referred to as stock tank oit and since measured prior to any production having taken place it was the volume initially in placd. ... 

The ERS may not be misunderstood as being the defect s real size, since it only considers the portion of sound being reflected by the defect, and therefore the influences of the shape, the surface condition and the orientation of the defect are not taken into consideration. Unfortunately a lot of criticism was loaded onto the DGS method, because exactly this mistake was made in the early days of the DGS technique, and many people described the DGS-method as a technique for defect sizing". 

The study of clean surfaces encompassed a lot of interest in the early days of surface science. From this, we now have a reasonable idea of the geometric and electronic structure of many clean surfaces, and the tools are readily available for obtaining this infonnation from other systems, as needed. 

As described above, classical infrared spectroscopy using grating spectrometers and gas cells provided some valuable infonnation in the early days of cluster spectroscopy, but is of limited scope. However, tire advent of tunable infrared lasers in tire 1980s opened up tire field and made rotationally resolved infrared spectra accessible for a wide range of species. As for microwave spectroscopy, tunable infrared laser spectroscopy has been applied botli in gas cells and in molecular beams. In a gas cell, tire increased sensitivity of laser spectroscopy makes it possible to work at much lower pressures, so tliat strong monomer absorjDtions are less troublesome. 

In Section V.A, we present a few analytical examples showing that the reshictions on the x-matrix elements are indeed quantization conditions that go back to the early days of quantum theory. Section V.B will be devoted to the general case. 

A vexing puzzle m the early days of valence bond theory concerned the fact that methane is CH4 and that the four bonds to carbon are directed toward the corners of a tetrahedron Valence bond theory is based on the overlap of half filled orbitals of the connected atoms but with an electron configuration of s 2s 2p 2py carbon has only two half filled orbitals (Figure 2 8a) How can it have bonds to four hydrogens ... 

The ubiquitous use of the word Tine to describe an experimentally observed transition goes back to the early days of observations of visible spectra with spectroscopes in which the lines observed in, say, the spectmm of a sodium flame are images, formed at various wavelengths, of the entrance slit. Although, nowadays, observations tend to be in the form of a plot of some measure of the intensity of the transition against wavelength, frequency or wavenumber, we still refer to peaks in such a spectmm as lines. 

In the early days following the discovery of chirality it was thought that only molecules of the type CWXYZ, multiply substituted methanes, were important in this respect and it was said that a molecule with an asymmetric carbon atom forms enantiomers. Nowadays, this definition is totally inadequate, for two reasons. The first is that the existence of enantiomers is not confined to molecules with a central carbon atom (it is not even confined to organic molecules), and the second is that, knowing what we do about the various possible elements of symmetry, the phrase asymmetric carbon atom has no real meaning. 

The method of excitation was, in the early days, by an electron beam but now a transverse electrical discharge, like that for the nitrogen laser shown in Figure 9.14, is used. Indeed such an excimer laser can be converted to a nitrogen laser by changing the gas. 

In the early days of KMnO manufacture, the yield was only two-thhds of the theoretical the yield of NaAlnO never exceeded one-half theoretical. It is now known that the formation of manganate(VI) from Mn02 passes through a manganate(V) step. 

A second type of index, the keyword-in-context (KWIC) index, arose during the early days of computer processing. The same entry would appear in a KWIC index as follows ... 

Sulfuric Acid Concentrators. Concentrators for increasing the strength of dilute sulfuric acid by removing water have been used since the early days of the industry. A two-volume text on this subject was pubHshed ia 1924 (135) more recent discussions of the subject are also available (32,136-141). 

Although in the early days of resin finishing there was continued debate over the mechanism by which these agents achieved smooth-dry performance, by the 1950s most textile chemists beHeved that cross-linking was primarily responsible for achieving smooth-dry performance. 

Coke deposition is essentially independent of space velocity. These observations, which were developed from the study of amorphous catalysts during the early days of catalytic cracking (11), stiU characteri2e the coking of modem day 2eohte FCC catalysts over a wide range of hydrogen-transfer (H-transfer) capabihties. 

Saffron is found in the pistils of the plant Crocus sativus. Saffron is often confused with safflower, sometimes known as bastard saffron. The name of the plant. Crocus sativus, comes from the Arabic word faran, meaning yellow. The Romans and the Greeks used saffron not only as a dye but also as a spice. In the early days of Greece, yellow was the official color, and Grecian women were especially fond of clothes dyed with saffron. Because of its scarcity, saffron ranked among the most expensive dyes of the ancient world. 

Heteroeyeles structurally based on the phenalene ring system form an interesting elass, frequently possessing distinetive eolours. With nitrogen as the central atom we have the unstable 9b-azaphenalene (24), whieh has only fairly reeently been prepared and is still comparatively little studied (76JCS(Pl)34l). The cyclazine nomenclature is commonly applied to this and related compounds thus, (24) is (3.3.3)cyclazine. With further aza substitution, in positions alternant to the central atom, their stability increases the heptaazaphenalene (25) is (thermally) a very inert compound, derivatives of which, e.g. the triamine, have been known since the early days of organic chemistry (see Chapter 2.20). 

The lip seal, or oil. seal, used on modern centrifugal pumps is borrowed from the automotive industry. The lip seal was born with the invention of the automobile transmission and the universal joint in the early days of the family ear. It would effectively retain the transmission fluid and U-joint grea.se on jalopies with rumble seats. It really hasn t changed much in design since the 1920s. 

Energy recovery has been standard practice from the early days of ammonia oxidation plants with escalating energy costs energy recovery is becoming increasingly important. 

The startup speed and temperature acceleration curves as shown in Figure 19-2 are one such safety measure. If the temperature or speed are not reached in a certain time span from ignition, the turbine will be shutdown. In the early days when these acceleration and temperature curves were not used, the fuel, which was not ignited, was carried from the combustor and then deposited at the first or second turbine nozzle, where the fuel combusted which resulted in the burnout of the turbine nozzles. After an aborted start the turbine must be fully purged of any fuel before the next start is attempted. To achieve the purge of any fuel residual from the turbine, there must be about seven times the turbine volume of air that must be exhausted before combustion is once again attempted. 

How is the diffraction pattern obtained in an x-ray experiment such as that shown in Figure 18.5b related to the crystal that caused the diffraction This question was addressed in the early days of x-ray crystallography by Sir Lawrence Bragg of Cambridge University, who showed that diffraction by a crystal can be regarded as the reflection of the primary beam by sets of parallel planes, rather like a set of mirrors, through the unit cells of the crystal (see Figure 18.6b and c). 

In the early days of protein crystallography the determination of a protein structure was laborious and time consuming. The diffracted beams were obtained from weak x-ray sources and recorded on films that had to be manually scanned and measured. The available computers were far from adequate for the problem, with a computing power roughly equal to present-day pocket calculators. Computer graphics were not available, and models of the protein had to be built manually from pieces of steel rod. To determine the... 

In the early days of TEM, sample preparation was divided into two categories, one for thin films and one for bulk materials. Thin-films, particularly metal layers, were often deposited on substrates and later removed by some sort of technique involving dissolution of the substrate. Bulk materials were cut and polished into thin slabs, which were then either electropolished (metals) or ion-milled (ceramics). The latter technique uses a focused ion beam (typically Ar+) of high-energy, which sputters the surface of the thinned slab. These techniques produce so-called plan-view thin foils. 

Whilst plastics materials have been associated with electrical and electronic applications since the early days of the electrical industry, developments over the... 

It has been common practice to blend plasticisers with certain polymers since the early days of the plastics industry when Alexander Parkes introduced Parkesine. When they were first used their function was primarily to act as spacers between the polymer molecules. Less energy was therefore required for molecular bond rotation and polymers became capable of flow at temperatures below their decomposition temperature. It was subsequently found that plasticisers could serve two additional purposes, to lower the melt viscosity and to change physical properties of the product such as to increase softness and flexibility and decrease the cold flex temperature (a measure of the temperature below which the polymer compound loses its flexibility). 

In the early days of the commercial development of PVC, emulsion polymers were preferred for general purpose applications. This was because these materials exist in the form of the fine primary particles of diameter of the order of 0.1-1.0 p,m, which in the case of some commercial grades aggregate into hollow secondary particles or cenospheres with diameters of 30-100 p,m. These emulsion polymer particles have a high surface/volume ratio and fluxing and gelation with plasticisers is rapid. The use of such polymers was, however, restricted because of the presence of large quantities of soaps and other additives necessary to emulsion polymerisation which adversely affect clarity and electrical insulation properties. 

In the early days of flight, eontrol surfaees of aireraft were operated by eables eonneeted between the eontrol eolumn and the elevators and ailerons. Modern high-speed aireraft require power-assisted deviees, or servomeehanisms to provide the large forees neeessary to operate the eontrol surfaees. 

Riccati, J.F. (1724) Animadversiones In Aequationes Differentiales, Acta Eruditorum Lipsiae. Re-printed by Bittanti, S. (ed.) (1989) Count Riccati and the Early Days of the Riccati Equation, Pitagora Editrice, Bologna, Milano. 

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