Ab Initio Calculations on the H_(2)+D_(2)=2HD Four‐Center Exchange Reaction. I. Elements of the Reaction Surface

We present the results of ab initio calculations on some interesting regions of the reaction surface for the four‐center exchange reaction H_(2)+D_(2)=2HD. These calculations, which use a minimum basis set of Slater orbitals, indicate that for all geometries appropriate to the transition state of the reaction, a barrier height of at least 148 kcal/mole is present. This is far greater than the energy required to produce free radicals and more than three times the experimental energy of activation, 42 kcal/mole. Considering the sources and magnitudes for errors due to correlation and basis set restrictions, we estimate the barrier height for this exchange reaction to be 132 ± 20 kcal/mole exclusive of zero‐point energies. In this paper we discuss the surface as determined by configuration interaction techniques. We find that the most favorable geometries for the exchange reactions are the square, rhombus, and kite configurations. However, all of these states are unstable with respect to H_(2) + 2H. In addition we find no evidence of collision complexes for any of the likely transition state geometries. In the following paper we will examine the G1 wavefunctions for this system in order to obtain an understanding of the factors responsible for the shape of the surface

A discussion Oof physical factors governing the distribution of microorganisms in the atmosphere

The preceding paper by Rittenberg, together with the number of articles on the same subject which have appeared recently, indicate an ever increasing interest on the part of biologists in the atmosphere as a medium for the dispersal of bacteria, molds, spores and pollens. Meteorologists, on the other hand, are interested in the results of such biological investigation to the extent that they show certain mixing processes within the atmosphere and the movements of air masses. In view of the large quantity of data which has already been accumulated by the biologists, it becomes of considerable interest to consider some of the results from the standpoint of fluid mechanics

Sea level departures of the California coast as related to the dynamics of the atmosphere over the North Pacific Ocean

Considerable attention is being directed at the present time toward fluctuations in sea level as related to the dynamics of the oceans and, to a lesser degree, the dynamics of the atmosphere. Most of the work along these lines, however, has been concerned with seasonal rather than nonperiodic variations. Nevertheless, an analysis of sea level data compiled over a period of many years at four California tidal stations indicates that non-periodic fluctuations of considerable magnitude also occur. Since these fluctuations are probably the direct or indirect result of variations in certain meteorological elements, it becomes of interest to investigate the nature of those atmospheric changes that occur simultaneously with changes in sea level

On the energy exchange between sea and atmosphere

The present paper is a preliminary report on an investigation of the exchange of heat and water vapor between the sea and atmosphere with particular reference to the regional and seasonal variations in these quantities over the North Atlantic and North Pacific oceans. The mean annual evaporation over the oceans according to latitude ranges can be considered fairly well established (Wüst, 1936; Mosby, 1936; McEwen, 1938), but there has been no extensive investigation of the seasonal and intra-latitudinal variations...

Flash Point and Chemical Composition of Aviation Kerosene (Jet A)

The relationship between chemical composition, flash point, and ignition energy was examined for eight samples of aviation kerosene (Jet A) with flash points between 29°C (84°F) and 74°C (165°F). We report the results of liquid characterization by two different laboratories. We use the results of headspace gas chromatography carried out by Woodrow and Seiber to characterize the vapor composition at liquid mass loading fractions of 3 and 400 kg/m^3. The composition data were analyzed to obtain analytical representations of vapor pressure and average molar mass as a function of temperature for each flash point fuel. The relationship between composition and flash point is examined by using two prediction methods. The first method is based on the notion of a critical value of fuel-air mass ratio at the flammability limit. The second method is based on Le Chatelier's rule for flammability limits. Both methods show a reasonable correlation between measured and predicted flash point. The relationship between flash point and ignition temperature threshold at a fixed spark ignition energy was examined for four fuels. A linear correlation was obtained for an ignition energy of 0.3 J. The effect of fuel weathering was examined by determining the flashpoints of seven fuel samples obtained from flight tests. The flash point increased about 8°C for fuel that had been exposed to 5 take-off, cruise, and landing cycles

Studies on the Effect of Ultra-Violet Rays upon Yeast Metabolism - I. The Effect of Ultra Violet Light upon the Medium

74. Studies on the effect Exposure of the medium (composed of optimum concentrations of salts and sugar) to ultra-violet light renders it less effective for the growth of yeast. The development of the toxicity increases with duration and intensity of irradiation. An exposure of seven hours through quartz at about l5 cm from a quartz mercury vapor lamp affects the medium in such a way that yeast will show practically no growth in the medium. The work is being continued in order to obtain quantitative results and to explain the phenomenon

Leadership and approaches to the management of workplace bullying

Leadership behaviour has been identified as an important antecedent of workplace bullying, since managers may prevent, permit or engage in the mistreatment of others. However, the issue of how managers respond when bullying occurs has received limited attention. With this in mind, the aim of this study was to explore how managers behave when bullying occurs in their work group, and to elucidate the contextual issues that underlie this behaviour. This was achieved through analysis of in-depth interviews with individuals involved in cases of bullying. The findings revealed a typology of four types of management behaviour in cases of bullying, each underpinned by contextual factors at the individual, group and organizational level. The study shows that the role of leadership in workplace bullying is more complex than previously thought, and suggests several ways in which managers and organizations could deal with bullying behaviour