2,291 research outputs found

    Multiple Heat Exchangers Simulation Within the Newton-Raphson Framework

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    A general framework is proposed for simulating complex heat exchanger geometries in a manner suitable for sequential solution of the refrigerant- and air-side equations for mass, momentum and energy. The sequential solution enables the algorithm to be applied to a single module of a complex heat exchanger, and then integrated with other modules within a simultaneous equation solver employing a Newton-Raphson approach. This report also describes the integration of component subroutines into system simulation models for air conditioners and refrigerators. The modular approach is illustrated by describing its application to a dual-evaporator refrigerator simulation.Air Conditioning and Refrigeration Project 6

    The Sheffield Wargames Corpus.

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    Recognition of speech in natural environments is a challenging task, even more so if this involves conversations between sev-eral speakers. Work on meeting recognition has addressed some of the significant challenges, mostly targeting formal, business style meetings where people are mostly in a static position in a room. Only limited data is available that contains high qual-ity near and far field data from real interactions between par-ticipants. In this paper we present a new corpus for research on speech recognition, speaker tracking and diarisation, based on recordings of native speakers of English playing a table-top wargame. The Sheffield Wargames Corpus comprises 7 hours of data from 10 recording sessions, obtained from 96 micro-phones, 3 video cameras and, most importantly, 3D location data provided by a sensor tracking system. The corpus repre-sents a unique resource, that provides for the first time location tracks (1.3Hz) of speakers that are constantly moving and talk-ing. The corpus is available for research purposes, and includes annotated development and evaluation test sets. Baseline results for close-talking and far field sets are included in this paper. 1

    A semi-analytic meshfree method for Almansi–Michell problems of piezoelectric cylinders

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    AbstractSaint-Venant’s Problem, Almansi–Michell Problems, Meshfree Methods, Piezoelectricity. We present a semi-analytical method for analyzing prismatic nonhomogeneous piezoelectric cylinders with arbitrary cross-sectional geometry. The prescribed loads considered in this study include axial forces, torques, moments, and voltage resultants prescribed at the cylinder’s ends, as well as body forces, lateral surface shears, voltages, and pressures as long as they can be represented by a power series in the axial coordinate. This problem can be considered as an extension of Saint-Venant and Almansi–Michell problems for elastic bodies to piezoelectric bodies. In this computationally efficient method, the cross-sectional plane is discretized with a meshfree approach, and the solution is obtained analytically with respect to the axial coordinate. A number of examples are provided to demonstrate the veracity and utility of the proposed method

    An application of recent developments of Data Envelopment Analysis to the evaluation of secondary schools in Portugal

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    This paper highlights the potentialities of Data Envelopment Analysis to evaluate the performance of organisations, using the concept of super-efficiency - an extension of DEA which increases its performance - and presents an example from the public sector to illustrate the method. The example selected is that of a school network where a place in a school can be seen as a perishable good, as places which are not occupied during an academic year are wasted. Results for the Portuguese Secondary school network show that the average efficiency of overcrowded schools, that is, those exceeding their capacity, is lower than that of schools which are less crowded. This shows clearly that overcrowded schools, on average, are less efficient in transforming their inputs into academic performance. It is this conviction, seldom proved scientifically, which leads governments and international organisations to recommend planning criteria for public facilities

    Renormalizability of Massive Gravity in Three Dimensions

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    We discuss renormalizability of a recently established, massive gravity theory with particular higher derivative terms in three space-time dimensions. It is shown that this massive gravity is certainly renormalizable as well as unitary, so it gives us a physically interesting toy model of perturbative quantum gravity in three dimensions.Comment: 13 pages, no figure

    Finite Density Algorithm in Lattice QCD -- a Canonical Ensemble Approach

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    I will review the finite density algorithm for lattice QCD based on finite chemical potential and summarize the associated difficulties. I will propose a canonical ensemble approach which projects out the finite baryon number sector from the fermion determinant. For this algorithm to work, it requires an efficient method for calculating the fermion determinant and a Monte Carlo algorithm which accommodates unbiased estimate of the probability. I shall report on the progress made along this direction with the Pad\'{e} - Z2_2 estimator of the determinant and its implementation in the newly developed Noisy Monte Carlo algorithm.Comment: Invited talk at Nankai Symposium on Mathematical Physics, Tianjin, Oct. 2001, 18 pages, 3 figures; expanded and references adde

    Gravitational Corrections to the Energy-Levels of a Hydrogen Atom

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    The first order perturbations of the energy levels of a hydrogen atom in central internal gravitational field are investigated. The internal gravitational field is produced by the mass of the atomic nucleus. The energy shifts are calculated for the relativistic 1S, 2S, 2P, 3S, 3P, 3D, 4S and 4P levels with Schwarzschild metric. The calculated results show that the gravitational corrections are sensitive to the total angular momentum quantum number.Comment: 7 page

    Situational Voluntary Compliance: Adherence to COVID-19 Social Distancing Guidelines in the 2020 Local Outbreak in Beijing

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    To mitigate the COVID-19 pandemic many countries have adopted mandatory social distancing measures, but in China, social distancing was implemented only as an advisory guideline. This article seeks to understand whether, and why Chinese citizens adhered to such social distancing advice. The data, derived from a survey in the 2020 local outbreak in Beijing, show that voluntary compliance was hardly influ-enced by motivational predictors, but was almost exclusively dependent on a single, key situational predictor, namely people’s practical capacity to follow social distancing. These findings demonstrate that the emphasis on intrinsic and extrinsic motivations in existing compliance research does not do justice to the situational nature of voluntary compliance observed within this particular context. We discuss theoretical implications of these findings for the compliance literature. Moreover, we use these findings to provide (tentative) insight into the compliance challenges that China was facing during the course of the pandemic, and to speculate about ways in which compliance may be enhanced during future pandemic outbreaks in China.</p
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