Accountable role

The Accountable role includes sponsoring the changes, specifying the end results, overseeing progress, and being held responsible for results. 

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There have been some studies of the equilibrium shape of two droplets pressed against each other (see Ref. 59) and of the rate of film Winning [60, 61], but these are based on hydrodynamic equations and do not take into account film-film barriers to final rupture. It is at this point, surely, that the chemistry of emulsion stabilization plays an important role. 

Energy minimisation and normal mode analysis have an important role to play in the study of the solid state. Algorithms similar to those discussed above are employed but an extra feature of such systems, at least when they form a perfect lattice, is that it is can be possible to exploit the space group symmetry of the lattice to speed up the calculations. It is also important to properly take the interactions with atoms in neighbouring cells into account. 

The equation does not take into account such pertubation factors as steric effects, solvent effects, and ion-pair formation. These factors, however, may be neglected when experiments are carried out in the same solvent at the same temperature and concentration for an homogeneous set of substrates. So, for a given ambident nucleophile the rate ratio kj/kj will depend on A and B, which vary with (a) the attacked electrophilic center, (b) the solvent, and (c) the counterpart cationic species of the anion. The important point in this kind of study is to change only one parameter at a time. This simple rule has not always been followed, and little systematic work has been done in this field (12) stiH widely open after the discovery of the role played by single electron transfer mechanism in ambident reactivity (1689). 

Even if the specific role attributed to benzothiazolium was not confirmed later (24), all these syntheses account for the significant and common behavior of quaternary salts, carbocations giving either symmetrical or asymmetrical reactive anhydrobases. They constitute the mam step in cyanine dye formation. 

For an account of Carothers role in the creation of nylon see the September 1988 issue of the Journal of Chemical Education (pp 803-808)... 

Deteriora.tlon. An important source of damage to stone objects is mechanical in nature. Both breakage and abrasion account for much of the losses on objects made of this relatively fragile material. More difficulties are offered by the processes of a chemical nature which play a role in stone deterioration (132—134). 

Product innovation absorbs considerable resources in the fine chemicals industry, in part because of the shorter life cycles of fine chemicals as compared to commodities. Consequently, research and development (R D) plays an important role. The main task of R D in fine chemicals is scaling-up lab processes, as described, eg, in the ORAC data bank or as provided by the customers, so that the processes can be transferred to pilot plants (see Pilot PLANTS AND microplants) and subsequently to industrial-scale production. Thus the R D department of a fine chemicals manufacturer typically is divided into a laboratory or process research section and a development section, the latter absorbing the Hon s share of the R D budget, which typically accounts for 5 to 10% of sales. Support functions include the analytical services, engineering, maintenance, and Hbrary. 

Cell Adhesion. The membranes of leukocytes and platelets contain a variety of components that promote ceU-surface contact. Although numerous ceU-surface molecules are likely to play a role in ceU-surface adhesion, the group of selectins are of particular interest to research on this subject. Selectins are molecules that are known to promote leukocyte—platelet adhesion. However, selectin-based models have not been able to account for the fact that platelets are allowed to pass through the filter and leukocytes are not. 

Pulse radiolysis results (74) have led other workers to conclude that adsorbed OH radicals (surface trapped holes) are the principal oxidants, whereas free hydroxyl radicals probably play a minor role, if any. Because the OH radical reacts with HO2 at a diffusion controlled rate, the reverse reaction, that is desorption of OH to the solution, seems highly unlikely. The surface trapped hole, as defined by equation 18, accounts for most of the observations which had previously led to the suggestion of OH radical oxidation. The formation of H2O2 and the observations of hydroxylated intermediate products could all occur via... 

Nonferrous alloys account for only about 2 wt % of the total chromium used ia the United States. Nonetheless, some of these appHcations are unique and constitute a vital role for chromium. Eor example, ia high temperature materials, chromium ia amounts of 15—30 wt % confers corrosion and oxidation resistance on the nickel-base and cobalt-base superaHoys used ia jet engines the familiar electrical resistance heating elements are made of Ni-Cr alloy and a variety of Ee-Ni and Ni-based alloys used ia a diverse array of appHcations, especially for nuclear reactors, depend on chromium for oxidation and corrosion resistance. Evaporated, amorphous, thin-film resistors based on Ni-Cr with A1 additions have the advantageous property of a near-2ero temperature coefficient of resistance (58). 

Over the last 30 years, ethanol s role as a solvent has increased sharply, while its role as a chemical intermediate has declined. In 1990, 59% of the 890 X 10 L demand was used for solvents and the remaining 41% was used for chemical intermediates (283). In 1960, solvents accounted for only 24% of the demand. The 1990 solvent uses were toiletries and cosmetics, 33% coatings, inks, and proprietary blends, 29% detergents and household cleaners, 14% external pharmaceuticals, 7% insecticides and disinfectants, 7% and miscellaneous, 10%. Ethanol demand for solvent appHcations has been fairly stable in recent years, growing at an average aimual rate of 2%. VOC regulations could impact its solvent use, particularly in areas like California, where ethanol in aerosols like hair spray and deodorants have come under scmtiny. 

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