6,351 research outputs found

    Identified particle measurements at large transverse momenta from p+p to Au+Au collisions at RHIC

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    Measurements of various particle species over an extended momentum range provide a sensitive experimental tool for investigating particle production mechanisms in hadronic collisions. Comparison of the spectral shapes from different collision centralities measured with the STAR detector at RHIC allows one to study the interplay of soft and hard particle production for mesons and investigate various baryon-meson effects. Systematic studies of identified particle spectra for various colliding systems and different incident energies provide additional insights toward the interplay between fragmentation and non-fragmentation contributions to the particle production. In these proceedings we present a systematic study of transverse momentum spectra for charged pions, protons and antiprotons from Au+Au and Cu+Cu data at sqrt(s_NN)=200 and 62.4 GeV as a function of collision centrality. We compare those measurements with p+p and d+Au data, investigating the system effects on energy loss.Comment: 6 pages, 4 figures, proceedings for the Lake Louise Winter Institute 2007, 19th-24th February 2007, Alberta, Canad

    Method of construction of a multi-cell solar array

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    The method of constructing a high voltage, low power, multicell solar array is described. A solar cell base region is formed in a substrate such as but not limited to silicon or sapphire. A protective coating is applied on the base and a patterned etching of the coating and base forms discrete base regions. A semiconductive junction and upper active region are formed in each base region, and defined by photolithography. Thus, discrete cells which are interconnected by metallic electrodes are formed

    High and low threshold P-channel metal oxide semiconductor process and description of microelectronics facility

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    The fabrication techniques and detail procedures for creating P-channel Metal-Oxide-Semiconductor (P-MOS) integrated circuits at George C. Marshall Space Flight Center (MSFC) are described. Examples of P-MOS integrated circuits fabricated at MSFC together with functional descriptions of each are given. Typical electrical characteristics of high and low threshold P-MOS discrete devices under given conditions are provided. A general description of MSFC design, mask making, packaging, and testing procedures is included. The capabilities described in this report are being utilized in: (1) research and development of new technology, (2) education of individuals in the various disciplines and technologies of the field of microelectronics, and (3) fabrication of many types of specially designed integrated circuits which are not commercially feasible in small quantities for in-house research and development programs

    System size dependence of freeze-out properties at RHIC

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    The STAR experiment at RHIC has measured identified pi(+/-), K(+/-) and p(pbar) spectra and ratios from sqrt(s_NN) = 62.4 and 200 GeV Cu+Cu collisions. The new Cu+Cu results are studied with hydro-motivated blast-wave and statistical model frameworks in order to characterize the freeze-out properties of this system. Along with measurements from Au+Au and p+p collisions, the obtained freeze-out parameters are discussed as a function of collision energy, system size, centrality and inferred energy density. This multi-dimensional systematic study reveals the importance of the collision geometry and furthers our understanding of the QCD phases.Comment: 6 pages, 6 figures, poster proceedings for the Quark Matter 2006 Conference, Shanghai, China, 14th-20th Novermber 2006, submitted to the International Journal of Modern Physics

    Distributed Roughness Effects on Blunt-Body Transition and Turbulent Heating

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    An experimental program has been conducted to obtain data on the effects of surface roughness on blunt bodies at laminar, transitional, and turbulent conditions. Wind tunnel models with distributed surface roughness heights from 0.06 mm to 1.75 mm were tested and heating data were obtained using global surface thermography. Heating rates of up to 85% higher than predicted, smooth-surface turbulent levels were measured
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