2,118 research outputs found

    Observation of the Mott Effect in Heavy Ion Collisions

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    Possibility of observing the Mott momentum in the distribution of the deuterons produced in the process p+nd+γp + n \to d + \gamma, in the first stage of a nuclear reaction is presented. The correlation of a hard photon with a deuteron allows to select those deuterons produced at the beginning of a reaction.Comment: 10 pages, 5 Postscript figure

    Influence of urbanization on home range size and habitat selection of raccoons in northeastern Illinois

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    With the spread of urban areas, gaining a greater understanding of the effect of human presence on wildlife species is essential for wildlife managers. I determined the influence of urbanization on home range size and habitat selection of raccoons (Procyon lotor). I examined habitat selection of 120 raccoons (52 males, 68 females) at 3 sites near Chicago, IL using radiotelemetry data collected from 1996 to 2000 during the summer season (June – August). These 3 sites differed considerably in degree of urbanization; one was rural, one suburban, and one urban. The study sites were partitioned into 5 habitat categories using aerial photographs: human use, aquatic, short grass, tall grass, and woodland. The Animal Movement extension in ArcView was used to generate fixed kernel home range estimates and thus determine home range size of each animal. Home ranges were found to be significantly larger at the rural site relative to the suburban and urban sites. These results suggest that raccoons were able to occupy smaller home ranges at the suburban and urban sites since food and shelter resources may be more concentrated around areas of human activity such as buildings, housing areas, dumpsters, and picnic areas. By analyzing the radiotelemetry data using the Animal Movement extension in ArcView and compositional analysis, habitat selection of raccoons was examined at the second-order home range, the second-order core-area use, and the third-order home range scales. Human use areas received the highest selection at the urban site, intermediate selection at the suburban site, and no significant selection at the rural site. This illustrates the importance of anthropogenic resources to urban and suburban raccoons. By examining the use of human use areas, managers can better understand the needs and behaviors of this urban wildlife species

    Hidden asymmetry and forward-backward correlations

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    A model-independent method of studying the forward-backward correlations in symmetric high energy processes is developed. The method allows a systematic study of properties of various particle sources and to uncover asymmetric structures hidden in symmetric hadron-hadron and nucleus-nucleus inelastic reactions.Comment: 11 pages, no figure

    Rapid hydrodynamic expansion in relativistic heavy-ion collisions

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    Hydrodynamic expansion of the hot fireball created in relativistic Au-Au collisions at 200GeV in 3+1-dimensions is studied. We obtain a simultaneous, satisfactory description of the transverse momentum spectra, elliptic flow and pion correlation radii for different collision centralities and different rapidities. Early initial time of the evolution is required to reproduce the interferometry data, which provides a strong indication of the early onset of collectivity. We can also constraint the shape of the initial energy density in the beam direction, with a relatively high initial energy density at the center of the fireball.Comment: 10 pages, 13 fig

    CMS ridge effect at LHC as a manifestation of bremstralung of gluons due to the quark-anti-quark string formation

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    The recently reported effect of long-range near-side angular correlations at LHC occurs for large multiplicities of particles with 1GeV<pT<3GeV1\,GeV\,<p_T\,<\,3\,GeV. To understand the effect several possibilities have been discussed. In the letter we propose a simple qualitative mechanism which corresponds to gluon bremstralung of quarks moving with acceleration appropriate to the quark--anti-quark string. The smallness of azimuthal angle difference Δϕ\Delta \phi along with large Δη\Delta \eta at large multiplicities in this interval of pTp_T are natural in the mechanism. The mechanism predicts also bremstralung photons with mean values of pT2.9p_T \approx 2.9 and 0.72GeV0.72\,GeV.Comment: 5 pages, 3 figure

    New generation of cable screw connectors for electrical power engineering systems

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    The article presents a material analysis for a new generation of cable screw connectors with shear bolts designed for not only 1st and 2nd class of cables but also 5tth class of aluminium and copper conductors that have not been previously supported. The set of properties of aluminium series 6xxx designated for screw connectors production has been determined. Finite Element Method (FEM) simulation of the controlled shear of the bolt at the body of the screw connector has been carried out. The repeatability of the bolt shear in the actual conditions was also conducted in order to verify the prototypes of the new generation of cable screw connectors

    Research on the threaded connection system from AlMgSi alloy for electrical power cables under various clamping loads

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    This article presents strain gauge tests showing the force loads in the connection system of power cables, with AlMgSi sheer bolts. Among others, the analysis of the influence of the tightening torque of the clamping unit on the distribution of forces and the evaluation of the strain in the entire system was carried out. The knowledge of the force conditions and loads in the threaded connection system allowed to develop, with the use of Finite Element Method (FEM) modelling, the optimal geometry and material of elements for the power cable connection system

    New generation of cable screw connectors for electrical power engineering systems

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    The article presents a material analysis for a new generation of cable screw connectors with shear bolts designed for not only 1st and 2nd class of cables but also 5tth class of aluminium and copper conductors that have not been previously supported. The set of properties of aluminium series 6xxx designated for screw connectors production has been determined. Finite Element Method (FEM) simulation of the controlled shear of the bolt at the body of the screw connector has been carried out. The repeatability of the bolt shear in the actual conditions was also conducted in order to verify the prototypes of the new generation of cable screw connectors

    Experimental Verification of the Chemical Sensitivity of Two-Site Double Core-Hole States Formed by an X-ray FEL

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    We have performed X-ray two-photon photoelectron spectroscopy (XTPPS) using the Linac Coherent Light Source (LCLS) X-ray free-electron laser (FEL) in order to study double core-hole (DCH) states of CO2, N2O and N2. The experiment verifies the theory behind the chemical sensitivity of two-site (ts) DCH states by comparing a set of small molecules with respect to the energy shift of the tsDCH state and by extracting the relevant parameters from this shift.Comment: 11 pages, 2 figure
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