Dynamics of structural defects and plasticity: models and numerical implementation for dynamical problems

We report the plasticity model with explicit description of kinetics of the material defects (dislocations, grain boundaries). This method becomes especially effective for computation of the dynamical deformation of materials at high strain rates because it allows for a simple accounting of the strain rate effects. The equation system is written out and discussed; its implementation is demonstrated for the problem of the plastic flow localization

The Formation of Galaxy Disks

We present a new set of multi-million particle SPH simulations of the formation of disk dominated galaxies in a cosmological context. Some of these galaxies are higher resolution versions of the models already described in Governato et al (2007). To correctly compare simulations with observations we create artificial images of our simulations and from them measure photometric Bulge to Disk (B/D) ratios and disk scale lengths. We show how feedback and high force and mass resolution are necessary ingredients to form galaxies that have flatter rotation curves, larger I band disk scale lengths and smaller B/D ratios. A new simulated disk galaxy has an I-band disk scale length of 9.2 kpc and a B/D flux ratio of 0.64 (face on, dust reddened).Comment: To appear in proceedings of "Formation and Evolution of Galaxy Disks", Rome, October 2007, Eds. J.G. Funes, S.J. and E.M. Corsini. Bigger figures than in printed versio

Core-log-seismic integration as a framework for determining the basin-wide significance of regional reflectors in the eastern equatorial Pacific

ODP Leg 138 in the eastern equatorial Pacific (EEP) provided a unique opportunity to understand the paleoceanographic significance of seismic reflectors in this climatically sensitive region. Carefully offset multiple cores were spliced into a complete stratigraphic section for the upper 250 m at each site and accurate, astronomically tuned time scales were generated from these composites. Well log data provided a means to correct composite depths to true depths as well as density and velocity data for the generation of synthetic seismograms. These synthetic seismograms were used to determine the paleoceanographic significance of regionally traceable reflectors by linking variations in the core record to the seismic record. The EEP reflectors are due to changes in carbonate content, primarily due to variations in surface productivity, as indicated by the presence of mats of the upwelling diatom Thalassiothrix longissima. The EEP composite GRAPE records were successfully used as a tuning target for GRAPE records in the central equatorial Pacific (CEP), as a means to detelxnine the basin-wide extent of EEP reflectors, and as a guide to the further interpretation of the CEP seismic record. It was found that EEP reflectors R3-t, R5, R6, R8-b, and Site 844 reflectors R 10, R 12-b and R 13, correspond to reflectors i n the CEP. However, some of the CEP reflectors, which were postulated to be due to periods of enhanced dissolution, also con\u27espond to diatom mats, and hence the origin of these reflectors must be reconsidered

THE EFFECT OF CHANGES IN RESERVE REQUIREMENTS DURING THE 1930s:

The differential response of cash reserves of member banks and nonmember banks not subject to the 1936-37 increase in reserve requirements is estimated to determine whether the 1937-38 recession was caused by the increase in reserve requirements. We identify 17 states that maintained constant reserve requirements from June 1934 to June 1941. While member banks increased their cash reserve ratios relative to nonmember banks, the magnitude of the adjustment is too small to have contributed to the 1937-38 recession. Shock prices and public reaction to the increase in reserve requirements are consistent with the empirical results. While the Fed was responsible for the Great Contraction, the results are inconsistent with the view the Fed’s reserve requirement increase contributed significantly to the 1937-38 recession.excess reserves, Federal Reserve, Great Depression, reserve requirements, 1937-38

The Origins of the German Corporation – Finance, Ownership and Control

The ownership of German corporations is quite different today from that of Anglo-American firms. How did this come about? To what extent is it attributable to regulation? A specially constructed data set on financing and ownership of German corporations from the end of the 19th century reveals that, as in the UK, there was a high degree of activity on German stock markets with firms issuing equity in preference to borrowing from banks, and insider and family ownership declining rapidly. However, unlike in the UK, other companies and banks emerged as the main holders of equity, with banks holding shares primarily as custodians of other investors rather than on their own account. The changing pattern of ownership concentration was therefore very different from that of the UK with regulation reinforcing the control that banks exercised on behalf of other investors

Chargino Production and Decay in Photon-Photon-Collisions

We discuss the pair production of charginos in collisions of polarized photons $\gamma\gamma \to \tilde{\chi}_i^+ \tilde{\chi}_i^-$, ($i=1,2$) and the subsequent leptonic decay of the lighter chargino $\tilde{\chi}_1^+ \to \tilde{\chi}_1^0 e^+ \nu_e$ including the complete spin correlations. Analytical formulae are given for the polarization and the spin-spin correlations of the charginos. Since the production is a pure QED process the decay dynamics can be studied separately. For high energy photons from Compton backscattering of polarized laser pulses off polarized electron beams numerical results are presented for the cross section, the angular distribution and the forward-backward asymmetry of the decay positron. Finally we study the dependence on the gaugino mass parameter $M_1$ and on the sneutrino mass for a gaugino-like MSSM scenario.Comment: 22 pages, 15 figures, version to be published in Eur. Phys. J.

Chelate-modified polymers for atmospheric gas chromatography

Chromatographic materials were developed to serve as the stationary phase of columns used in the separation of atmospheric gases. These materials consist of a crosslinked porous polymer matrix, e.g., a divinylbenzene polymer, into which has been embedded an inorganic complexed ion such as N,N'-ethylene-bis-(acetylacetoniminato)-cobalt (2). Organic nitrogenous bases, such as pyridine, may be incorporated into the chelate polymer complexes to increase their chromatographic utility. With such materials, the process of gas chromatography is greatly simplified, especially in terms of time and quantity of material needed for a gas separation