Effects of gamma radiation on SCR'S used in switching mode and in application to attitude control motor drive bridge

Effects of cobalt 60 gamma radiation on silicon control rectifiers used in switching mod

The determinations of consistent orderings for the sor iterative method

The concept of consistent ordering is central to the theory of the successive over-relaxation (SOR) iterative method for the solution of the set of equations Ax = b. (1

Multifluid, Magnetohydrodynamic Shock Waves with Grain Dynamics II. Dust and the Critical Speed for C Shocks

This is the second in a series of papers on the effects of dust on multifluid, MHD shock waves in weakly ionized molecular gas. We investigate the influence of dust on the critical shock speed, v_crit, above which C shocks cease to exist. Chernoff showed that v_crit cannot exceed the grain magnetosound speed, v_gms, if dust grains are dynamically well coupled to the magnetic field. We present numerical simulations of steady shocks where the grains may be well- or poorly coupled to the field. We use a time-dependent, multifluid MHD code that models the plasma as a system of interacting fluids: neutral particles, ions, electrons, and various ``dust fluids'' comprised of grains with different sizes and charges. Our simulations include grain inertia and grain charge fluctuations but to highlight the essential physics we assume adiabatic flow, single-size grains, and neglect the effects of chemistry. We show that the existence of a phase speed v_phi does not necessarily mean that C shocks will form for all shock speeds v_s less than v_phi. When the grains are weakly coupled to the field, steady, adiabatic shocks resemble shocks with no dust: the transition to J type flow occurs at v_crit = 2.76 v_nA, where v_nA is the neutral Alfven speed, and steady shocks with v_s > 2.76 v_nA are J shocks with magnetic precursors in the ion-electron fluid. When the grains are strongly coupled to the field, v_crit = min(2.76 v_nA, v_gms). Shocks with v_crit < v_s < v_gms have magnetic precursors in the ion-electron-dust fluid. Shocks with v_s > v_gms have no magnetic precursor in any fluid. We present time-dependent calculations to study the formation of steady multifluid shocks. The dynamics differ qualitatively depending on whether or not the grains and field are well coupled.Comment: 43 pages with 17 figures, aastex, accepted by The Astrophysical Journa

Covalent bonding of antibodies of polystyrene latex beads: A concept

Technique facilitates purification of vaccines and production of immunoadsorption columns exhibiting relatively long stability. Information interests biochemists, medical researchers, and pharmaceutical manufacturers

Carrier transport coefficients across GaAs-GaAIAs (100) interfaces

We present calculations of reflection and transmission coefficients for electrons and holes at (100) interfaces for the GaAs–Ga_(1–x)Al_xAs system. We consider semi‐infinite crystals of the two semiconductors joined at an abrupt or compositionally graded interface. The calculations are performed using the empirical tight binding approximation. The transport coefficients were computed as a function of the components of the incident carrier wavevector normal and parallel to the interface. We have investigated the transport coefficients for incident states near various band minima into different final state channels. The transmission into states with qualitatively similar character to the incident state is found to be much greater than transmission into states of different character. For example, an electron near the X minimum normal to the interface in Ga_(1–xAl_xAs transmits into the X valley of GaAs with much greater probability than it transmits into the Γ minimum of GaAs. We have investigated the dependence of the transport coefficients on alloy composition. The effect of compositional grading of the interface on the transport coefficients has also been investigated

Adverse socioeconomic conditions in childhood and cause specific adult mortality: prospective observational study

&lt;b&gt;Objective:&lt;/b&gt; To investigate the association between social circumstances in childhood and mortality from various causes of death in adulthood. Design: Prospective observational study. Setting: 27 workplaces in the west of Scotland. &lt;b&gt;Subjects:&lt;/b&gt; 5645 men aged 35-64 years at the time of examination. &lt;b&gt;Main outcome measures:&lt;/b&gt; Death from various causes. &lt;b&gt;Results:&lt;/b&gt; Men whose fathers had manual occupations when they were children were more likely as adults to have manual jobs and be living in deprived areas. Gradients in mortality from coronary heart disease, stroke, lung cancer, stomach cancer, and respiratory disease were seen (all P&#60;0.05), generally increasing from men whose fathers had professional and managerial occupations (social class I and II) to those whose fathers had semiskilled and unskilled manual occupations (social class IV and V). Relative rates of mortality adjusted for age for men with fathers in manual versus non-manual occupations were 1.52 (95&#37; confidence interval 1.24 to 1.87) for coronary heart disease, 1.83 (1.13 to 2.94) for stroke, 1.65 (1.12 to 2.43) for lung cancer, 2.06 (0.93 to 4.57) for stomach cancer, and 2.01 (1.17 to 3.48) for respiratory disease. Mortality from other cancers and accidental and violent death showed no association with fathers' social class. Adjustment for adult socioeconomic circumstances and risk factors did not alter results for mortality from stroke and stomach cancer, attenuated the increased risk of coronary heart disease and respiratory disease, and essentially eliminated the association with lung cancer. &lt;b&gt;Conclusions:&lt;/b&gt; Adverse socioeconomic circumstances in childhood have a specific influence on mortality from stroke and stomach cancer in adulthood, which is not due to the continuity of social disadvantage throughout life. Deprivation in childhood influences risk of mortality from coronary heart disease and respiratory disease in adulthood, although an additive influence of adulthood circumstances is seen in these cases. Mortality from lung cancer, other cancer, and accidents and violence is predominantly influenced by risk factors that are related to social circumstances in adulthood

Some social and physical correlates of intergenerational social mobility: evidence from the west of Scotland Collaborative Study

Mainstream sociological studies of intergenerational social mobility have emphasised social factors such as education and the material and cultural resources of the family of origin as the main influences on the chances and direction of social mobility. Medical sociology in contrast has been more interested in its physical correlates such as height and health status. Data from the West of Scotland Collaborative study allow an examination of the relationship between social mobility and both social and physical factors. Height, education and material circumstances in the family of origin, indexed as the number of siblings, were each independently associated with the chances of both upward and downward social mobility in this dataset. In each case the net effect of this social mobility was to constrain the social distribution of these variables. Any role which these factors may play in indirect health selection, it is argued, cannot account for social class differences in adult health

Viscosity and Thermal Relaxation for a resonantly interacting Fermi gas

The viscous and thermal relaxation rates of an interacting fermion gas are calculated as functions of temperature and scattering length, using a many-body scattering matrix which incorporates medium effects due to Fermi blocking of intermediate states. These effects are demonstrated to be large close to the transition temperature $T_c$ to the superfluid state. For a homogeneous gas in the unitarity limit, the relaxation rates are increased by nearly an order of magnitude compared to their value obtained in the absence of medium effects due to the Cooper instability at $T_c$. For trapped gases the corresponding ratio is found to be about three due to the averaging over the inhomogeneous density distribution. The effect of superfluidity below $T_c$ is considered to leading order in the ratio between the energy gap and the transition temperature.Comment: 7 pages, 3 figure