20,850 research outputs found

    Design of a second life product family from the perspective of the remanufacturing agent

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    This thesis presents a method of solving a newly posed Second Life Product Family Design problem. This is unique in that the architecture of the product is not speci ed to be identical to one of the recaptured products, rather it is determined through optimization. The problem is framed using Conjoint Analysis and the Multi Nomial Logit Model, formatted with respect to components available for inclusion in the nal products and then solved using an implementation of Genetic Algorithms. The solution method is also encapsulated in a software module which can be disseminated to industrial users without a background in optimization or familiarity with Genetic Algorithms. A case study is performed to determine the e ectiveness of the proposed solution method, and analyze the in uences di erent market conditions and component similarities can have on the optimal design. It is concluded that the proposed method converges to an optimal Second Life Product Family Design

    ARE CATTLE ON FEED REPORT REVISIONS RANDOM AND DOES INDUSTRY ANTICIPATE THEM?

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    Cattle on Feed (COF) reports are an important source of beef supply information. This study investigates whether COF report revisions are unbiased, random, and anticipated. Initial COF reports are biased, but the bias is economically small. Revisions to COF estimates are not random. Market analysts do not correctly anticipate revisions.Livestock Production/Industries,

    Electromagnetic cascade in high energy electron, positron, and photon interactions with intense laser pulses

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    The interaction of high energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution, which suppresses the emission of high energy photons, thus reducing the number of electron-positron pairs being generated. Therefore, this type of interaction suppresses the development of the electromagnetic avalanche-type discharge, i.e., the exponential growth of the number of electrons, positrons, and photons does not occur in the course of interaction. The suppression will occur when 3D effects can be neglected in the transverse particle orbits, i.e., for sufficiently broad laser pulses with intensities that are not too extreme. The final distributions of electrons, positrons, and photons are calculated for the case of a high energy e-beam interacting with a counter-streaming, short intense laser pulse. The energy loss of the e-beam, which requires a self-consistent quantum description, plays an important role in this process, as well as provides a clear experimental observable for the transition from the classical to quantum regime of interaction.Comment: 13 pages, 7 figure

    Crossover to Potential Energy Landscape Dominated Dynamics in a Model Glass-forming Liquid

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    An equilibrated model glass-forming liquid is studied by mapping successive configurations produced by molecular dynamics simulation onto a time series of inherent structures (local minima in the potential energy). Using this ``inherent dynamics'' approach we find direct numerical evidence for the long held view that below a crossover temperature, TxT_x, the liquid's dynamics can be separated into (i) vibrations around inherent structures and (ii) transitions between inherent structures (M. Goldstein, J. Chem. Phys. {\bf 51}, 3728 (1969)), i.e., the dynamics become ``dominated'' by the potential energy landscape. In agreement with previous proposals, we find that TxT_x is within the vicinity of the mode-coupling critical temperature TcT_c. We further find that at the lowest temperature simulated (close to TxT_x), transitions between inherent structures involve cooperative, string like rearrangements of groups of particles moving distances substantially smaller than the average interparticle distance.Comment: Expanded from 4 to 7 page

    Solution of nonlinear algebraic equations characteristic of filter circuits Summary technical report

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    Digital computer program developed for solving nonlinear algebraic equations characteristic of filter circuit

    Optical signatures of quantum delocalization over extended domains in photosynthetic membranes

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    The prospect of coherent dynamics and excitonic delocalization across several light-harvesting structures in photosynthetic membranes is of considerable interest, but challenging to explore experimentally. Here we demonstrate theoretically that the excitonic delocalization across extended domains involving several light-harvesting complexes can lead to unambiguous signatures in the optical response, specifically, linear absorption spectra. We characterize, under experimentally established conditions of molecular assembly and protein-induced inhomogeneities, the optical absorption in these arrays from polarized and unpolarized excitation, and demonstrate that it can be used as a diagnostic tool to determine the coherent coupling among iso-energetic light-harvesting structures. The knowledge of these couplings would then provide further insight into the dynamical properties of transfer, such as facilitating the accurate determination of F\"orster rates.Comment: 4 figures and Supplementary information with 7 figures. To appear in Journal of physical chemistry A, 201
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