96 research outputs found

    2021 roadmap on lithium sulfur batteries

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    Batteries that extend performance beyond the intrinsic limits of Li-ion batteries are among the most important developments required to continue the revolution promised by electrochemical devices. Of these next-generation batteries, lithium sulfur (Li–S) chemistry is among the most commercially mature, with cells offering a substantial increase in gravimetric energy density, reduced costs and improved safety prospects. However, there remain outstanding issues to advance the commercial prospects of the technology and benefit from the economies of scale felt by Li-ion cells, including improving both the rate performance and longevity of cells. To address these challenges, the Faraday Institution, the UK's independent institute for electrochemical energy storage science and technology, launched the Lithium Sulfur Technology Accelerator (LiSTAR) programme in October 2019. This Roadmap, authored by researchers and partners of the LiSTAR programme, is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the LiSTAR consortium. In compiling this Roadmap we hope to aid the development of the wider Li–S research community, providing a guide for academia, industry, government and funding agencies in this important and rapidly developing research space

    Development of a distributed international patient data registry for hairy cell leukemia

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    Hairy cell leukemia (HCL) is a rare lymphoproliferative disorder, comprising only 2% of all leukemias. The Hairy Cell Leukemia Foundation (HCLF) has developed a patient data registry to enable investigators to better study the clinical features, treatment outcomes, and complications of patients with HCL. This system utilizes a centralized registry architecture. Patients are enrolled at HCL Centers of Excellence (COE) or via a web-based portal. All data are de-identified, which reduces regulatory burden and increases opportunities for data access and re-use. To date, 579 patients have been enrolled in the registry. Efforts are underway to engage additional COE’s to expand access to patients across the globe. This international PDR will enable researchers to study outcomes in HCL in ways not previously possible due to the rarity of the disease and will serve as a platform for future prospective research

    Real Estate valuation and forecasting in non-homogeneous markets: A case study in Greece during the financial crisis

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    In this paper we develop an automatic valuation model for property valuation using a large database of historical prices from Greece. The Greek property market is an inefficient, nonhomogeneous market, still at its infancy and governed by lack of information. As a result modelling the Greek real estate market is a very interesting and challenging problem. The available data cover a wide range of properties across time and include the financial crisis period in Greece which led to tremendous changes in the dynamics of the real estate market. We formulate and compare linear and non-linear models based on regression, hedonic equations and artificial neural networks. The forecasting ability of each method is evaluated out-of-sample. Special care is given on measuring the success of the forecasts but also on identifying the property characteristics that lead to large forecasting errors. Finally, by examining the strengths and the performance of each method we apply a combined forecasting rule to improve forecasting accuracy. Our results indicate that the proposed methodology constitutes an accurate tool for property valuation in a non-homogeneous, newly developed market

    2021 roadmap on lithium sulfur batteries

    Get PDF
    Abstract: Batteries that extend performance beyond the intrinsic limits of Li-ion batteries are among the most important developments required to continue the revolution promised by electrochemical devices. Of these next-generation batteries, lithium sulfur (Li–S) chemistry is among the most commercially mature, with cells offering a substantial increase in gravimetric energy density, reduced costs and improved safety prospects. However, there remain outstanding issues to advance the commercial prospects of the technology and benefit from the economies of scale felt by Li-ion cells, including improving both the rate performance and longevity of cells. To address these challenges, the Faraday Institution, the UK’s independent institute for electrochemical energy storage science and technology, launched the Lithium Sulfur Technology Accelerator (LiSTAR) programme in October 2019. This Roadmap, authored by researchers and partners of the LiSTAR programme, is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the LiSTAR consortium. In compiling this Roadmap we hope to aid the development of the wider Li–S research community, providing a guide for academia, industry, government and funding agencies in this important and rapidly developing research space

    Interfacial shear stress in wavy stratified gas-liquid flow in horizontal pipes

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    The scope of this study was to improve the Andritsos-Hanratty model for estimating interfacial friction factor and pressure drop in horizontal stratified gas-liquid two-phase flow. New experimental results (focusing on the effects of gas density and surface tension), combined with experimental data available in the literature, permit the development of semi-theoretical correlations for the transition from smooth stratified to 2-D wave region and from the latter to large-amplitude wave region and of different empirical relations for the interfacial friction factor in the two wave regions. The transition correlations agree reasonably well with existing and new data obtained in this work and the modified relations give improved predictions for both liquid holdup and pressure drop during gas-liquid stratified flow in horizontal and slightly downward pipelines as deduced from a statistical analysis of the results. (C) 2013 Elsevier Ltd. All rights reserved

    Distributed clustering of categorical data using the information bottleneck framework

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    We perform clustering of categorical data using the Information Bottleneck, (IB), framework at large scale. We examine the performance of existing solutions using multiple machine architectures. The IB method uses information theory to recast database relations as probability distributions and the proximity of their tuples as their loss of information when they are considered together. More precisely, we study the Agglomerative Information Bottleneck, the Sequential Information Bottleneck and LIMBO, a newer approach that uses summaries of the original data. First we evaluate the performance and limitations of these algorithms when confronted with large datasets in a single, powerful machine. We then propose new implementations that take advantage of distributed environments. Using real and large synthetic datasets of tens of Gigabytes in size, we finally evaluate their effectiveness and efficiency

    Modelling Tomato Dehydration in a Tunnel Dryer Using Geothermal Energy

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    Low-temperature geothermal waters can be used efficiently in drying various vegetables and fruits, replacing sun-drying or drying using conventional fuels. A geothermal tomato dehydration plant has been operating since 2001 in Neo Erasmio, northern Greece, producing high-quality, sun-dried tomatoes. The unit uses low-cost geothermal water to heat atmospheric air to 56-58 degrees C, which is introduced in a specially designed tunnel-type dryer. The scope of this work is to model the aforementioned tomato-drying process that uses low-enthalpy geothermal energy. The modelling procedure consists of two stages: the first stage focuses on the modelling of a single tomato piece, whereas the second stage is concerned with the modelling of air drying of tomatoes in a tunnel with trays moving in batches. The influence of air velocity, air temperature, and tomato tray loading on the drying process was investigated. The effect of flow configuration, i.e., co-current or counter-current operation, on the drying characteristics was also explored. The model can be used for the design and optimization of the continuous drying process existing in Neo Erasmio and can be easily extended and modified to deal with other agricultural products and tunnel designs

    Calcium carbonate scaling in a plate heat exchanger in the presence of particles

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    Scale formation of CaCO3 in a plate heat exchanger is investigated in the presence of various types of added particles under isothermal conditions. The parameters examined include the degree of supersaturation, the type of particles, the flow velocity, the particle concentration and the direction of flow inside the heat exchanger. The key result of this work is the strong synergistic effect of fine aragonite particles on the deposition rate and the morphology of the deposits. On the contrary, the presence of fine titanium oxide and of relatively large calcite particles does not seem to affect the main scaling characteristics of CaCO3. (C) 2003 Elsevier Ltd. All rights reserved
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