Cno Abundances Of Hydrogen-Deficient Carbon And R Coronae Borealis Stars: A View Of The Nucleosynthesis In A White Dwarf Merger

We present high-resolution (R similar to 50,000) observations of near-IR transitions of CO and CN of the five known hydrogen-deficient carbon (HdC) stars and four R Coronae Borealis (RCB) stars. We perform an abundance analysis of these stars by using spectrum synthesis and state-of-the-art MARCS model atmospheres for cool hydrogen-deficient stars. Our analysis confirms reports by Clayton and colleagues that those HdC stars exhibiting CO lines in their spectrum and the cool RCB star SAps are strongly enriched in (18)O(with (16)O/(18)Oratios ranging from 0.3 to 16). Nitrogen and carbon are in the form of (14)N and (12)C, respectively. Elemental abundances for CNO are obtained from C I, Ci2, CN, and CO lines. Difficulties in deriving the carbon abundance are discussed. Abundances of Na from Na I lines and S from S I lines are obtained. Elemental and isotopic CNO abundances suggest that HdC and RCB stars may be related objects, and that they probably formed from a merger of an He white dwarf with a C-O white dwarf.Robert A. Welch Foundation of Houston, TexasSwedish Research CouncilGS-2006A-C-13GS-2007A-DD-1McDonald Observator

The Ethical Practice of Human-Centered Civil Justice Design

Over the past two decades, legal professionals have increasingly engaged in a new form of professional activity: civil justice design. In the past, legal professionals handled cases and transactions for clients or served as neutrals, including mediators and arbitrators, who helped to resolve disputes between parties. Today, legal professionals increasingly play a principal design role in creating systems that resolve streams of conflicts, disputes, and grievances between parties. Lawyers regularly now create internal grievance procedures, procedures for companies to resolve disputes with customers, and court-annexed alternative dispute resolution systems. The emergence of this new role raises difficult questions about the ethics and responsibilities that attach to legal professionals who serve as civil justice designers. The primary ethical dilemma for these civil justice designers will be the tension between, on the one hand, maximizing a client\u27s interest and, on the other, providing the public with vibrant, fair, just, and legitimate institutions for resolving disputes. The Model Rules of Professional Conduct offer little guidance on how to resolve these tensions, and socialization into the legal profession may lead legal professionals to distance themselves from ethical responsibilities. These trends and conditions may result in systemic civil justice problems and a tragedy of the commons, which saps the longevity of our legal institutions. Yet there is a wider more virtuous moral principle that applies to all human relations: the principle of neighborly morality. In this article, I discuss the principle of neighborly morality and an analytical framework developed by professors Howard Gardner, Mihaly Csikszentmihalyi, and William Damon for understanding role ethics. I discuss the ethical responsibilities that apply to civil justice designers, including the criteria of excellence, engagement, and ethics, and a reflective practice of dispute system design, human-centered civil justice design, which assists civil justice designers in resolving this tension

A Case History of Chemical Attack of a Clay Shale

This paper describes the results of an extensive investigation made to determine the cause of excessive settlements of two 800 MN steam turbine units located at the Four Corners Steam Electric Station near Farmington, New Mexico. The units are located on a clay-shale formation with numerous gypsum seams. The settlement was originally attributed to the solutioning of these gypsum seams. It was found that the construction of a large unlined cooling pond raised the ground water table in the vicinity of the power plant. In this saturated environment, a chemical attack of the existing clay shales began. It is believed that the chemical reaction causing the degradation of the clay-shale has been identified and that a chemical solution to the problem has been found. The reaction involves the removal of the exchangeable cation from the clay lattice, which goes into solution. As the cations are leached out, the clays tend to weather toward the montmorillonite end of the transformation series

A computer program for hydrostatic bearings including the effects of non-uniform film thickness and relative velocity for various methods of lubricant supply final technical report

Computer program for hydrostatic bearing - effects of nonuniform film thickness and lubricant suppl

Gas damping force noise on a macroscopic test body in an infinite gas reservoir

We present a simple analysis of the force noise associated with the mechanical damping of the motion of a test body surrounded by a large volume of rarefied gas. The calculation is performed considering the momentum imparted by inelastic collisions against the sides of a cubic test mass, and for other geometries for which the force noise could be an experimental limitation. In addition to arriving at an accurated estimate, by two alternative methods, we discuss the limits of the applicability of this analysis to realistic experimental configurations in which a test body is surrounded by residual gas inside an enclosure that is only slightly larger than the test body itself.Comment: 8 pages. updated with correct translational damping coefficient for cylinder on axis. added cylinder orthogonal to symmetry axis, force and torque. slightly edited throughou

Invisible Pension Investments

A large share of the more than $6.28 trillion in private pension plan assets is held in certain types of indirect investment vehicles. If those vehicles file their own annual return with the Department of Labor they are called “direct filing entities” (or DFEs), and pension plans that invest in them are excused from providing detailed information concerning the assets, liabilities, and investment performance of the DFEs. Consequently, the publicly-available summary financial information reported by pension plans investing through one or more DFEs is seriously incomplete: while a plan must identify the categorical nature of its direct investments (for example, as common or preferred stock, corporate or government debt, real estate, etc.), indirect investments through a DFE are reported only as interests in the DFE, without regard to the underlying nature of the DFE’s assets and liabilities. Matching the DFE’s return with the returns filed by plans that invest through the DFE is theoretically possible, but it is technically difficult and has not been comprehensively achieved. This study undertakes the task of linking returns filed by large private pension plans and DFEs in 2008. After explaining the types of DFEs, summary statistics on the extent of pension plan investment through DFEs and the composition of DFE portfolios are reported. The process employed to link the holdings of each DFE to its investor-plans is described, followed by description and analysis of the results. Important differences in the asset allocations of pension plans of various types are revealed, and the portfolio compositions of plans that do and do not invest through DFEs are compared. Because thirty-five percent of plans that invest in a DFE are found to file internally inconsistent returns that preclude successful linking of DFE financial information to the investor-plan, the plan characteristics associated with such deficient filings are investigated. Although the composition of DFE portfolios is currently invisible to plan participants and the general public, we find little evidence that DFEs have been systematically exploited to obscure the identity of pension plan investments. Finally, the results of this study are reviewed in light of the purposes of pension plan financial disclosure. Even if routine, accurate, and comprehensive matching of DFE financial information with investor-plans were available, ERISA’s text and policies support the regulatory formulation of a far more detailed digital disclosure regime.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116092/1/vatr13.pd

Sub-milliarcsecond precision spectro-astrometry of Be stars

The origin of the disks around Be stars is still not known. Further progress requires a proper parametrization of their structure, both spatially and kinematically. This is challenging as the disks are very small. Here we assess whether a novel method is capable of providing these data. We obtained spectro astrometry around the Pa beta line of two bright Be stars, alpha Col and zeta Tau, to search for disk signatures. The data, with a pixel to pixel precision of the centroid position of 0.3..0.4 milliarcsecond is the most accurate such data to date. Artefacts at the 0.85 mas level are present in the data, but these are readily identified as they were non-repeatable in our redundant datasets. This does illustrate the need of taking multiple data to avoid spurious detections. The data are compared with simple model simulations of the spectro astrometric signatures due to rotating disks around Be stars. The upper limits we find for the disk radii correspond to disk sizes of a few dozen stellar radii if they rotate Keplerian. This is very close to observationally measured and theoretically expected disk sizes, and this paper therefore demonstrates that spectro-astrometry, of which we present the first such attempt, has the potential to resolve the disks around Be stars.Comment: 6 pages, A&A accepte

Sensitivity analysis of the reactor safety study

Originally presented as the first author's thesis, (M.S.) in the M.I.T. Dept. of Nuclear Engineering, 1979.The Reactor Safety Study (RSS) or Wash-1400 developed a methodology estimating the public risk from light water nuclear reactors. In order to give further insights into this study, a sensitivity analysis has been performed to determine the significant contributors to risk for both the PWR and BWR. The sensitivity to variation of the point values of the failure probabilities reported in the RSS was determined for the safety systems identified therein, as well as for many of the generic classes from which individual failures contributed to system failures. Increasing as well as decreasing point values were considered. An analysis of the sensitivity to increasing uncertainty in system failure probabilities was also performed. The sensitivity parameters chosen were release category prob- abilities, core melt probability, and the risk parameters of early fatalities, latent cancers and total property damage. The latter three are adequate for describing all public risks identified in the RSS. The results indicate reductions of public risk by less than a factor of two for factor reductions in system or generic failure probabilities as hignh as one hundred. There also appears to be more benefit in monitoring the most sensitive systems to verify adherence to RSS failure rates than to backfitting present reactors. The sensitivity analysis results do indicate, however, possible benefits in reducing human error rates.Final report for research project sponsored by Northeast Utilities Service Company, Yankee Atomic Electric Company under the M.I.T. Energy Laboratory Electric Utility Program