Classical Hadrodynamics: A New Approach to Ultrarelativistic Heavy-Ion Collisions

We discuss a new approach to ultrarelativistic heavy-ion collisions based on classical hadrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach that includes automatically spacetime nonlocality and retardation, nonequilibrium phenomena, interactions among all nucleons and particle production. In the current version of our theory, we consider $N$ extended unexcited nucleons interacting with massive neutral scalar ($\sigma$) and neutral vector ($\omega$) meson fields. The resulting classical relativistic many-body equations of motion are solved numerically without further approximation for soft nucleon-nucleon collisions at $p_{\rm lab}$ = 14.6, 30, 60, 100 and 200 GeV/$c$ to yield the transverse momentum imparted to the nucleons. For the future development of the theory, the isovector pseudoscalar ($\pi^+$, $\pi^-$, $\pi^0$), isovector scalar ($\delta^+$, $\delta^-$, $\delta^0$), isovector vector ($\rho^+$, $\rho^-$, $\rho^0$) and neutral pseudoscalar ($\eta$) meson fields that are known to be important from nucleon-nucleon scattering experiments should be incorporated. In addition, the effects of quantum uncertainty on the equations of motion should be included by use of techniques analogous to those used by Moniz and Sharp for nonrelativistic quantum electrodynamics.Comment: 6 pages, LA-UR-94-217

A study of commuter air service

A regionally oriented overview of the commuter air service industry is provided. A framework for an eventual assessment of potential technology directions that may be of benefit to the industry is presented. Data are provided on the industry's market characteristics, service patterns, patronage characteristics, aircraft and airport needs, economic characteristics and institutional issues. Using personal interview and literature survey methods, investigation of a considerable cross-section of the industry was made

Recent advances in structural technology for large deployable and erectable spacecraft

Ultra-low mass deployable and erectable truss structure designs for spacecraft are identified using computerized structural sizing techniques. Extremely slender strut proportions are shown to characterize minimum mass spacecraft which are designed for shuttle transport to orbit. Discrete element effects using a recently developed buckling theory for periodic lattice type structures are presented. An analysis of fabrication imperfection effects on the surface accuracy of four different antenna reflector structures is summarized. The tetrahedral truss has the greatest potential of the structures examined for application to accurate or large reflectors. A deployable module which can be efficiently transported is identified and shown to have significant potential for application to future antenna requirements. Investigations of erectable structure assembly are reviewed

Reduction of errors in vibratory gyroscopes by double modulation

Reduction of errors in vibratory gyroscopes by double modulatio

Reconstruction subgrid models for nonpremixed combustion

Large-eddy simulation of combustion problems involves highly nonlinear terms that, when filtered, result in a contribution from subgrid fluctuations of scalars, Z, to the dynamics of the filtered value. This subgrid contribution requires modeling. Reconstruction models try to recover as much information as possible from the resolved field Z, based on a deconvolution procedure to obtain an intermediate field ZM. The approximate reconstruction using moments (ARM) method combines approximate reconstruction, a purely mathematical procedure, with additional physics-based information required to match specific scalar moments, in the simplest case, the Reynolds-averaged value of the subgrid variance. Here, results from the analysis of the ARM model in the case of a spatially evolving turbulent plane jet are presented. A priori and a posteriori evaluations using data from direct numerical simulation are carried out. The nonlinearities considered are representative of reacting flows: power functions, the dependence of the density on the mixture fraction (relevant for conserved scalar approaches) and the Arrhenius nonlinearity (very localized in Z space). Comparisons are made against the more popular beta probability density function (PDF) approach in the a priori analysis, trying to define ranges of validity for each approach. The results show that the ARM model is able to capture the subgrid part of the variance accurately over a wide range of filter sizes and performs well for the different nonlinearities, giving uniformly better predictions than the beta PDF for the polynomial case. In the case of the density and Arrhenius nonlinearities, the relative performance of the ARM and traditional PDF approaches depends on the size of the subgrid variance with respect to a characteristic scale of each function. Furthermore, the sources of error associated with the ARM method are considered and analytical bounds on that error are obtained

Structural sizing considerations for large space structures

A number of missions for the space shuttle were proposed which involve placing large truss platforms on-orbit. These platforms range in size from tens of meters in span for reflector application to several thousand meters for solar power collector application. These proposed sizes and the operational requirements considered are unconventional in comparison to Earthbound structures and little information exists concerning efficient proportions of the structural elements forming the framework of the platforms. Such proportions are of major concern because they have a strong influence on the packaging efficiency and, thus, the transportation effectiveness of the shuttle. The present study is undertaken to: (1) identify efficient ranges of application of deployable and erectable platforms configured for shuttle transport to orbit, and (2) determine sensitivity to key parameters of minimum mass deployable and erectable platform designs

Transcript of The 127-Pound Halibut

This story is an excerpt from a longer interview that was collected as part of the Launching through the Surf: The Dory Fleet of Pacific City project. In this story, Robert Bush recounts the challenges of catching a 127-pound halibut

Letter, George Bush to Abraham Lincoln Association, September 11, 1992

This typed letter, dated September 11, 1992, is written from George Bush to Abraham Lincoln Association in which Bush sends greetings to the Members of the Association during the special conference on the President Lincoln and offers the hosting universities his congratulations. The letter goes on to talk about Lincoln\u27s character and importance to the history of the nation and concludes by wishing the association a successful conference. The letter is typed on White House letterhead.https://scholarsjunction.msstate.edu/fvw-manuscripts-original-manuscripts/1121/thumbnail.jp

Christian change agents : analyzing the effectiveness of a Christian leadership program among students in a central Kentucky restoration church

https://place.asburyseminary.edu/ecommonsatsdissertations/2550/thumbnail.jp