19,863 research outputs found

    Flow properties of suspensions rich in solids

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    Mathematical evaluation of flow properties of fluids carrying high concentrations of solids in suspension relates suspension viscosity to physical properties of the solids and liquids, and provides a means for predicting flow behavior. A technique for calculating a suspensions flow rates is applicable to the design of pipelines

    Enhancing the work of the Islington Integrated Gangs Team: A pilot study on the response to serious youth violence in Islington

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    This report is the result of research conducted by the Centre for City Criminology at City, University of London, in partnership with Islington’s Integrated Gangs Team (IGT) and the Metropolitan Police Service (MPS). The research was co-funded by MPS and the School of Arts and Social Sciences, City, University of London. Following a collaborative research event in October 2017, City Criminologists were commissioned to carry out a small-scale research project to capture the work of the IGT and to make recommendations regarding its operations, coherence, effectiveness and sustainability. The research team conducted semi-structured interviews over several months with 23 practitioners across the services that constitute the IGT. This report presents the findings and recommendations

    Temperature Dependent Neutron Scattering Sections for Polyethylene

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    This note presents neutron scattering cross sections for polyethylene at 296 K, 77 K and 4 K derived from a new scattering kernel for neutron scattering off of hydrogen in polyethylene. The kernel was developed in ENDF-6 format as a set of S(alpha,beta) tables using the LEAPR module of the NJOY94 code package. The polyethylene density of states (from 0 to sub eV) adopted to derive the new kernel is presented. We compare our calculated room temperature total scattering cross sections and double differential cross sections at 232 meV at various angles with the available experimental data (at room temperature), and then extrapolate the calculations to lower temperatures (77K and 4K). The new temperature dependent scattering kernel gives a good quantitative fit to the available room temperature data and has a temperature dependence that is qualitatively consistent with thermodynamics.Comment: 6 page

    Instantaneous current prediction for Naval Operations

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    OCEANS2005, MTS/IEEE Conference Proceedings, DVD-ROMNaval operations depend highly upon environmental conditions that can either adversely affect successful completion or hinder the safety of personnel. Each warfare community has defined environmental thresholds and operating limits that restrict the execution of any intended maneuver. As the warfare environment continues to shift from the open ocean to the littoral, prediction of the shallow water environment is an urgent need in order to support these operations. The value-aided of using a hydrodynamic model (WQMAP) for the mission planning of the naval operations in San Diego Bay is demonstrated in this study. A new model verification procedure (i.e., compatibility verification) is proposed for the tidal dominated littoral basin prediction

    Conditional operation of a spin qubit

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    We report coherent operation of a singlet-triplet qubit controlled by the arrangement of two electrons in an adjacent double quantum dot. The system we investigate consists of two pairs of capacitively coupled double quantum dots fabricated by electrostatic gates on the surface of a GaAs heterostructure. We extract the strength of the capacitive coupling between qubit and double quantum dot and show that the present geometry allows fast conditional gate operation, opening pathways to multi-qubit control and implementation of quantum algorithms with spin qubits.Comment: related papers here: http://marcuslab.harvard.ed

    Introduction

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    What are the strategies, modalities and aspirations of island-based, stateless nationalist and regionalist parties in the twenty-first century? Political independence is now easier to achieve, even by the smallest of territories; yet, it is not so likely to be pursued with any vigour by the world's various persisting sub-national (and mainly island) jurisdictions. Theirs is a pursuit of different expressions of sub-national autonomy, stopping short of independence. And yet, a number of independence referenda are scheduled, including one looming in Scotland in autumn 2014

    Thermal Properties of Pineapple Leaf Composite and its Suitability as a Viable Alternative for Efficient Roofing Material

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    For self-cooling building designs, the thermal properties of pineapple (Ananas Comosus) stalk composite were investigated and compared with those of asbestos with a view to establishing its suitability as ceiling material. Sample boards from pineapple leaves were prepared by drying and grinding, then forming them into boards without an external binder. The major parameter, thermal conductivity К was determined using Lee’s Disc apparatus. Other parameters determined were specific heat capacity c, density ρ, thermal resistivity ρth, thermal diffusivity λ, and thermal absorptivity α, were determined by using the appropriate experimental methods or calculations. The thermal conductivity of Ananas Comosus was determined to be 0.0719±0.0007Wm-1K-1. Using the same Lee’s Disc apparatus method, the thermal conductivity of the commercial asbestos ceiling sheet was measured to be 0.195Wm-1K-1. This value is about 85% of the value (0.17Wm-1K-1) \) quoted in textbooks. Our pineapple stalk sheet is clearly a poorer heat conductor than the asbestos sheet.  Other parameters determined here – the specific heat capacity, the thermal diffusivity, etc, support our findings that the investigated material can serve as a good material for efficient “cool roof” building desig

    The Impact of Atmospheric Fluctuations on Degree-scale Imaging of the Cosmic Microwave Background

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    Fluctuations in the brightness of the Earth's atmosphere originating from water vapor are an important source of noise for ground-based instruments attempting to measure anisotropy in the Cosmic Microwave Background. This paper presents a model for the atmospheric fluctuations and derives simple expressions to predict the contribution of the atmosphere to experimental measurements. Data from the South Pole and from the Atacama Desert in Chile, two of the driest places on Earth, are used to assess the level of fluctuations at each site.Comment: 29 pages, 7 figures, 1 table, appears in The Astrophysical Journa
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