Hybrid thermocouple development program

The design and development of a hybrid thermocouple, having a segmented SiGe-PbTe n-leg encapsulated within a hollow cylindrical p-SiGe leg, is described. Hybrid couple efficiency is calculated to be 10% to 15% better than that of a all-SiGe couple. A preliminary design of a planar RTG, employing hybrid couples and a water heat pipe radiator, is described as an example of a possible system application. Hybrid couples, fabricated initially, were characterized by higher than predicted resistance and, in some cases, bond separations. Couples made later in the program, using improved fabrication techniques, exhibited normal resistances, both as-fabricated and after 700 hours of testing. Two flat-plate sections of the reference design thermoelectric converter were fabricated and delivered to NASA Lewis for testing and evaluation

Probing Nucleon Strangeness with Neutrinos: Nuclear Model Dependences

The extraction of the nucleon's strangeness axial charge, Delta_s, from inclusive, quasielastic neutral current neutrino cross sections is studied within the framework of the plane-wave impulse approximation. We find that the value of Delta_s can depend significantly on the choice of nuclear model used in analyzing the quasielastic cross section. This model-dependence may be reduced by one order of magnitude when Delta_s is extracted from the ratio of total proton to neutron yields. We apply this analysis to the interpretation of low-energy neutrino cross sections and arrive at a nuclear theory uncertainty of plus/minus 0.03 on the value of Delta_s expected to be determined from the ratio of proton and neutron yields measured by the LSND collaboration. This error compares favorably with estimates of the SU(3)-breaking uncertainty in the value of Delta_s extracted from inclusive, polarized deep-inelastic structure function measurements. We also point out several general features of the quasielastic neutral current neutrino cross section and compare them with the analogous features in inclusive, quasielastic electron scattering.Comment: 40 pages (including 11 postscript figures), uses REVTeX and epsfig.st

Measurement of glucose exclusion from the fully hydrated DOPE inverse hexagonal phase

The degree of exclusion of glucose from the inverse hexagonal HII phase of fully hydrated DOPE is determined using contrast variation small angle neutron scattering and small angle X-ray scattering. The presence of glucose is found to favour the formation of the non-lamellar HII phase over the fluid lamellar phase, over a wide range of temperatures, while having no significant effect on the structure of the HII phase. Glucose is preferentially excluded from the lipid¿water interface resulting in a glucose concentration in the HII phase of less than half that in the coexisting aqueous phase. The degree of exclusion is quantified and the results are consistent with a hydration layer of pure water adjacent to the lipid head groups from which glucose is excluded. The osmotic gradient created by the difference in glucose concentration is determined and the influence of glucose on the phase behaviour of non-lamellar phase forming lipid systems is discussed

Partonic Energy Loss and the Drell-Yan Process

We examine the current status of the extraction of the rate of partonic energy loss in nuclei from A dependent data. The advantages and difficulties of using the Drell-Yan process to measure the energy loss of a parton traversing a cold nuclear medium are discussed. The prospects of using relatively low energy proton beams for a definitive measurement of partonic energy loss are presented.Comment: 12 pages, 2 figure

Juror First Votes in Criminal Trials

Our analysis of the voting behavior of over 3,000 jurors in felony cases tried in Los Angeles, Maricopa County, the District of Columbia, and the Bronx reveals that only in D.C. does a juror\u27s race appear to relate to how he or she votes. African-American jurors in D.C. appear more apt to vote not guilty on the jury\u27s first ballot in cases involving minority defendants charged with drug offenses. We find no evidence, however, that this effect survives into the jury\u27s final verdict

Tribute to Paul Oberst

A tribute to Professor Paul Oberst

Juror First Votes in Criminal Trials

Our analysis of the voting behavior of over 3,000 jurors in felony cases tried in Los Angeles, Maricopa County, the District of Columbia, and the Bronx reveals that only in D.C. does a juror\u27s race appear to relate to how he or she votes. African-American jurors in D.C. appear more apt to vote not guilty on the jury\u27s first ballot in cases involving minority defendants charged with drug offenses. We find no evidence, however, that this effect survives into the jury\u27s final verdict