Source of CP Violation for the Baryon Asymmetry of the Universe

We give a description of why the existence of a fourth generation is likely to provide enough CP violation for baryogenesis, and trace how this observation came about. We survey the current experimental and theoretical pursuits and outline a research agenda, touching upon unitarity violation and very heavy chiral quarks, and comment on how the electroweak phase transition picture might be altered.Comment: Invited talk presented at 2nd International Workshop on Dark Matter, Dark Energy and Matter-antimatter Asymmetry, Hsinchu, Taiwan, November 5-6, 201

The Superscattering Matrix for Two Dimensional Black Holes

A consistent Euclidean semi classical calculation is given for the superscattering operator $\$$ in the RST model for states with a constant flux of energy. The $\$$ operator is CPT invariant. There is no loss of quantum coherence when the energy flux is less than a critical rate and complete loss when the energy flux is critical.Comment: 12 pages (R/94/4

On the discrepancies in the low energy neutron-deuteron breakup

In view of recent neutron-deuteron (nd) breakup data for neutron-neutron (nn) and neutron-proton (np) quasi-free-scattering (QFS) arrangements and the large discrepancy found between theoretical predictions and measured nn QFS cross sections, we analyze the sensitivity of the QFS cross sections to different partial wave components of the nucleon-nucleon (NN) interaction. We found that the QFS cross section is strongly dominated by the 1S0 and 3S1-3D1 contributions. Because the standard three-nucleon force (3NF) only weakly influence the QFS region, we conjecture, that it must be the nn 1S0 force component which is responsible for the discrepancy in the nn QFS peak. A stronger 1S0 nn force is required to bring theory and data into agreement. Such an increased strength of the nn interaction will, however, not help to explain the nd breakup symmetric-space-star (SST) discrepancy. Further experimental cross-checkings are required.Comment: 17 pages, 10 figure

Investigation of Micro Porosity Sintered wick in Vapor Chamber for Fan Less Design

Micro Porosity Sintered wick is made from metal injection molding processes, which provides a wick density with micro scale. It can keep more than 53 % working fluid inside the wick structure, and presents good pumping ability on working fluid transmission by fine infiltrated effect. Capillary pumping ability is the important factor in heat pipe design, and those general applications on wick structure are manufactured with groove type or screen type. Gravity affects capillary of these two types more than a sintered wick structure does, and mass heat transfer through vaporized working fluid determines the thermal performance of a vapor chamber. First of all, high density of porous wick supports high transmission ability of working fluid. The wick porosity is sintered in micro scale, which limits the bubble size while working fluid vaporizing on vapor section. Maximum heat transfer capacity increases dramatically as thermal resistance of wick decreases. This study on permeability design of wick structure is 0.5 - 0.7, especially permeability (R) = 0.5 can have the best performance, and its heat conductivity is 20 times to a heat pipe with diameter (Phi) = 10mm. Test data of this vapor chamber shows thermal performance increases over 33 %.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Unified models of the cosmological dark sector

We model the cosmological substratum by a viscous fluid that is supposed to provide a unified description of the dark sector and pressureless baryonic matter. In the homogeneous and isotropic background the \textit{total} energy density of this mixture behaves as a generalized Chaplygin gas. The perturbations of this energy density are intrinsically non-adiabatic and source relative entropy perturbations. The resulting baryonic matter power spectrum is shown to be compatible with the 2dFGRS and SDSS (DR7) data. A joint statistical analysis, using also Hubble-function and supernovae Ia data, shows that, different from other studies, there exists a maximum in the probability distribution for a negative present value $q_{0} \approx - 0.53$ of the deceleration parameter. Moreover, different from other approaches, the unified model presented here favors a matter content that is of the order of the baryonic matter abundance suggested by big-bang nucleosynthesis.Comment: 4 pages, 1 figure, submitted to the Proceedings of the Spanish Relativity Meeting - ERE 2010, Granada, September 6 - September 10, 201

van Vleck determinants: geodesic focussing and defocussing in Lorentzian spacetimes

The van Vleck determinant is an ubiquitous object, arising in many physically interesting situations such as: (1) WKB approximations to quantum time evolution operators and Green functions. (2) Adiabatic approximations to heat kernels. (3) One loop approximations to functional integrals. (4) The theory of caustics in geometrical optics and ultrasonics. (5) The focussing and defocussing of geodesic flows in Riemannian manifolds. While all of these topics are interrelated, the present paper is particularly concerned with the last case and presents extensive theoretical developments that aid in the computation of the van Vleck determinant associated with geodesic flows in Lorentzian spacetimes. {\sl A fortiori} these developments have important implications for the entire array of topics indicated. PACS: 04.20.-q, 04.20.Cv, 04.60.+n. To appear in Physical Review D47 (1993) 15 March.Comment: plain LaTeX, 18 page

Two-stage coaxial gas compressor

Compressor raises pressure of gases from low ambient supply during space experiments by a system of low weight, size, and power input. Dc rotary-torque motor and ball-screw drive shaft activate first and second stage of compressor, utilizing inertia forces to operate check valves