Validation and Simulation of ARES I Scale Model Acoustic Test -1- Pathfinder Development

The Ares I Scale Model Acoustics Test (ASMAT) is a series of live-fire tests of scaled rocket motors meant to simulate the conditions of the Ares I launch configuration. These tests have provided a well documented set of high fidelity measurements useful for validation including data taken over a range of test conditions and containing phenomena like Ignition Over-Pressure and water suppression of acoustics. To take advantage of this data, a digital representation of the ASMAT test setup has been constructed and test firings of the motor have been simulated using the Loci/CHEM computational fluid dynamics software. Within this first of a series of papers, results from ASMAT simulations with the rocket in a held down configuration and without water suppression have then been compared to acoustic data collected from similar live-fire tests to assess the accuracy of the simulations. Detailed evaluations of the mesh features, mesh length scales relative to acoustic signals, Courant-Friedrichs-Lewy numbers, and spatial residual sources have been performed to support this assessment. Results of acoustic comparisons have shown good correlation with the amplitude and temporal shape of pressure features and reasonable spectral accuracy up to approximately 1000 Hz. Major plume and acoustic features have been well captured including the plume shock structure, the igniter pulse transient, and the ignition overpressure. Finally, acoustic propagation patterns illustrated a previously unconsidered issue of tower placement inline with the high intensity overpressure propagation path

Assessment of Autoimmune Responses Associated with Asbestos Exposure in Libby, Montana, USA

Systemic autoimmune responses are associated with certain environmental exposures, including crystalline particles such as silica. Positive antinuclear antibody (ANA) tests have been reported in small cohorts exposed to asbestos, but many questions remain regarding the prevalence, pattern, and significance of autoantibodies associated with asbestos exposures. The population in Libby, Montana, provides a unique opportunity for such a study because of both occupational and environmental exposures that have occurred as a result of the mining of asbestos-contaminated vermiculite near the community. As part of a multifaceted assessment of the impact of asbestos exposures on this population, this study explored the possibility of exacerbated autoimmune responses. Age- and sex-matched sets of 50 serum samples from Libby and Missoula, Montana (unexposed), were tested for ANA on HEp-2 cells using indirect immune, fluorescence. Data included frequency of positive tests, ANA titers, staining patterns, and scored fluorescence intensity, all against known controls. Serum immunoglobulin A (IgA), rheumatoid factor, and antibodies to extractable nuclear antigen (ENA) were also tested. The Libby samples showed significantly higher frequency of positive ANA and ENA tests, increased mean fluorescence intensity and titers of the ANAs, and higher serum IgA, compared with Missoula samples. In the Libby samples, positive correlations were found between ANA titers and both lung disease severity and extent of exposure. The results support the hypothesis that asbestos exposure is associated with autoimmune responses and suggests that a relationship exists between those responses and asbestos-related disease processes

Teleological Essentialism

Placeholder essentialism is the view that there is a causal essence that holds category members together, though we may not know what the essence is. Sometimes the placeholder can be filled in by scientific essences, such as when we acquire scientific knowledge that the atomic weight of gold is 79. We challenge the view that placeholders are elaborated by scientific essences. On our view, if placeholders are elaborated, they are elaborated Aristotelian essences, a telos. Utilizing the same kinds of experiments used by traditional essentialists—involving superficial change (study 1), transformation of insides (study 2), acquired traits (study 3) and inferences about offspring (study 4)—we find support for the view that essences are elaborated by a telos. And we find evidence (study 5) that teleological essences may generate category judgments

The environment power system analysis tool development program

The Environment Power System Analysis Tool (EPSAT) is being developed to provide space power system design engineers with an analysis tool for determining system performance of power systems in both naturally occurring and self-induced environments. The program is producing an easy to use computer aided engineering (CAE) tool general enough to provide a vehicle for technology transfer from space scientists and engineers to power system design engineers. The results of the project after two years of a three year development program are given. The EPSAT approach separates the CAE tool into three distinct functional units: a modern user interface to present information, a data dictionary interpreter to coordinate analysis; and a data base for storing system designs and results of analysis

Omnivorousness in sport: The importance of social capital and networks

There has been for some time a significant and growing body of research around the relationship between sport and social capital. Similarly, within sociology there has been a corpus of work that has acknowledged the emergence of the omnivore–univore relationship. Surprisingly, relatively few studies examining sport and social capital have taken the omnivore–univore framework as a basis for understanding the relationship between sport and social capital. This gap in the sociology of sport literature and knowledge is rectified by this study that takes not Putnam, Coleman or Bourdieu, but Lin’s social network approach to social capital. The implications of this article are that researchers investigating sport and social capital need to understand more about how social networks and places for sport work to create social capital and, in particular, influence participating in sporting activities. The results indicate that social networks both facilitate and constrain sports participation; whilst family and friendship networks are central in active lifestyles, those who are less active have limited networks

Symplectic quantization, inequivalent quantum theories, and Heisenberg's principle of uncertainty

We analyze the quantum dynamics of the non-relativistic two-dimensional isotropic harmonic oscillator in Heisenberg's picture. Such a system is taken as toy model to analyze some of the various quantum theories that can be built from the application of Dirac's quantization rule to the various symplectic structures recently reported for this classical system. It is pointed out that that these quantum theories are inequivalent in the sense that the mean values for the operators (observables) associated with the same physical classical observable do not agree with each other. The inequivalence does not arise from ambiguities in the ordering of operators but from the fact of having several symplectic structures defined with respect to the same set of coordinates. It is also shown that the uncertainty relations between the fundamental observables depend on the particular quantum theory chosen. It is important to emphasize that these (somehow paradoxical) results emerge from the combination of two paradigms: Dirac's quantization rule and the usual Copenhagen interpretation of quantum mechanics.Comment: 8 pages, LaTex file, no figures. Accepted for publication in Phys. Rev.

Isometric group actions on Banach spaces and representations vanishing at infinity

Our main result is that the simple Lie group $G=Sp(n,1)$ acts properly isometrically on $L^p(G)$ if $p>4n+2$. To prove this, we introduce property ({\BP}_0^V), for $V$ be a Banach space: a locally compact group $G$ has property ({\BP}_0^V) if every affine isometric action of $G$ on $V$, such that the linear part is a $C_0$-representation of $G$, either has a fixed point or is metrically proper. We prove that solvable groups, connected Lie groups, and linear algebraic groups over a local field of characteristic zero, have property ({\BP}_0^V). As a consequence for unitary representations, we characterize those groups in the latter classes for which the first cohomology with respect to the left regular representation on $L^2(G)$ is non-zero; and we characterize uniform lattices in those groups for which the first $L^2$-Betti number is non-zero.Comment: 28 page

Decision and Discovery in Defining “Disease”

This version (May 17, 2005) was published in its final form as: Schwartz PH. Decision and discovery in defining 'disease'. In: Kincaid H, McKitrick J, editors. Establishing medical reality: essays in the metaphysics and epistemology of biomedical science. Dordrecht: Springer; 2007. p. 47-63. http://dx.doi.org/10.1007/1-4020-5216-2_5The debate over how to analyze the concept of disease has often centered on the question of whether to include a reference to values, in particular the ‘disvalue’of diseases, or whether to avoid such notions. ‘Normativists,’such as King ([1954], 1981) and Culver and Gert (1982) emphasize the undesirability of diseases, while ‘Naturalists,’ most prominently Christopher Boorse (1977, 1987, 1997), instead require just the presence of biological dysfunction. The debate between normativism and naturalism often deteriorates into stalemate, with each side able to point out significant problems with the other. It starts to look as if neither approach can work. In this paper, I argue that the standoff stems from deeply questionable assumptions that have been used to formulate the opposing positions and guide the debate. In the end, I propose an alternative set of guidelines that offer a more constructive way to devise and compare theories

Photoelectrochemical Hydrogen Evolution Using Si Microwire Arrays

Arrays of B-doped p-Si microwires, diffusion-doped with P to form a radial n+ emitter and subsequently coated with a 1.5-nm-thick discontinuous film of evaporated Pt, were used as photocathodes for H_2 evolution from water. These electrodes yielded thermodynamically based energy-conversion efficiencies >5% under 1 sun solar simulation, despite absorbing less than 50% of the above-band-gap incident photons. Analogous p-Si wire-array electrodes yielded efficiencies <0.2%, largely limited by the low photovoltage generated at the p-Si/H_2O junction