Модернизация ректификационной колонны разделения пропан-пропиленовой фракции

Объектом проектирования является ректификационная колонна непрерывного действия для разделения пропан пропиленовой фракции, а также конденсатора-холодильника для конденсации пропилена. Целью работы является расчет ректификационной колонны и конденсатора-холодильника. В ходе расчета колонны был составлен материальный баланс колонны, рассчитано оптимальное флегмовое число и оптимальное значение числа теоретических тарелок. Так же был выполнен конструктивно-механический расчет. Входе которого определили исполнительную марку стали ректификационной колонны, условия прочности и устойчивости, найдены значения толщины стенки цилиндрической обечайки, эллиптических днища и крышки. Произведен расчет штуцеров и фланцев. В технологическом расчете теплообменника был составлен тепловой баланс. РассчитаныThe design object is a continuous distillation column for the separation of propane propylene fraction, as well as a condenser-cooler for condensation of propylene. The aim of the work is to calculate the distillation column and condenser-refrigerator. During the calculation of the column, the material balance of the column was compiled, the optimal reflux ratio and the optimal value of the number of theoretical plates were calculated. A structural and mechanical calculation was also performed. The inlet of which the executive grade of the distillation column was determined, the strength and stability conditions, the wall thickness of the cylindrical shell, elliptical bottom and cover were found. Calculation of fittings and flanges. In the technological calculation of the heat exchanger,

Motives and comprehension in a public goods game with induced emotions

This study analyses the sensitivity of public goods contributions through the lens of psychological motives. We report the results of a public goods experiment in which subjects were induced with the motives of care and anger through autobiographical recall. Subjects' preferences, beliefs, and perceptions under each motive are compared with those of subjects experiencing a neutral autobiographical recall control condition. We find, but only for those subjects with the highest comprehension of the game, that care elicits significantly higher contributions than anger, with the control treatment in between. This positive influence of the care motive on unconditional giving is accounted for partly by preferences for giving and partly by the beliefs concerning greater contributions by others. Anger also affects attention to own and other's payoffs (using mouse tracking) and perceptions of the game's incentive structure (cooperative or competitive)

Search for neutral charmless B decays at LEP

A search for rare charmless decays of \Bd and \Bs mesons has been performed in the exclusive channels \Bd_{(\mathrm s)}\ra\eta\eta, \Bd_{(\mathrm s)}\ra\eta\pio and \Bd_{(\mathrm s)}\ra\pio\pio. The data sample consisted of three million hadronic \Zo decays collected by the L3 experiment at LEP from 1991 through 1994. No candidate event has been observed and the following upper limits at 90\% confidence level on the branching ratios have been set \begin{displaymath} \mathrm{Br}(\Bd\ra\eta\eta)<4.1\times 10^{-4},\,\, \mathrm{Br}(\Bs\ra\eta\eta)<1.5\times 10^{-3},\,\, \end{displaymath} \begin{displaymath} \mathrm{Br}(\Bd\ra\eta\pio)<2.5\times 10^{-4},\,\, \mathrm{Br}(\Bs\ra\eta\pio)<1.0\times 10^{-3},\,\, \end{displaymath} \begin{displaymath} \mathrm{Br}(\Bd\ra\pio\pio)<6.0\times 10^{-5},\,\, \mathrm{Br}(\Bs\ra\pio\pio)<2.1\times 10^{-4}. \end{displaymath} These are the first experimental limits on \Bd\ra\eta\eta and on the \Bs neutral charmless modes

Galaxy Clusters Associated with Short GRBs. II. Predictions for the Rate of Short GRBs in Field and Cluster Early-Type Galaxies

We determine the relative rates of short GRBs in cluster and field early-type galaxies as a function of the age probability distribution of their progenitors, P(\tau) \propto \tau^n. This analysis takes advantage of the difference in the growth of stellar mass in clusters and in the field, which arises from the combined effects of the galaxy stellar mass function, the early-type fraction, and the dependence of star formation history on mass and environment. This approach complements the use of the early- to late-type host galaxy ratio, with the added benefit that the star formation histories of early-type galaxies are simpler than those of late-type galaxies, and any systematic differences between progenitors in early- and late-type galaxies are removed. We find that the ratio varies from R(cluster)/R(field) ~ 0.5 for n = -2 to ~ 3 for n = 2. Current observations indicate a ratio of about 2, corresponding to n ~ 0 - 1. This is similar to the value inferred from the ratio of short GRBs in early- and late-type hosts, but it differs from the value of n ~ -1 for NS binaries in the Milky Way. We stress that this general approach can be easily modified with improved knowledge of the effects of environment and mass on the build-up of stellar mass, as well as the effect of globular clusters on the short GRB rate. It can also be used to assess the age distribution of Type Ia supernova progenitors.Comment: ApJ accepted versio

Measurement of cross sections and leptonic forward-backward asymmetries at the Z pole and determination of electroweak parameters

We report on the measurement of the leptonic and hadronic cross sections and leptonic forward-backward asymmetries at the Z peak with the L3 detector at LEP. The total luminosity of 40.8 pb −1 collected in the years 1990, 1991 and 1992 corresponds to 1.09·10 6 hadronic and 0.98·10 5 leptonic Z decays observed. These data allow us to determine the electroweak parameters. From the cross sections we derive the properties of the Z boson: assuming lepton universality. We obtain an invisible width of Γ inv =496.5±7.9 MeV which, in the Standard Model, corresponds to a number of light neutrino species of N v =2.981±0.050.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47894/1/10052_2005_Article_BF01574160.pd