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A framework for dynamic modelling of railway track switches considering the switch blades,actuators and control systems

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Railway Engineering Science 2024年第2期32卷 162-176页

作者： Saikat Dutta Tim Harrison christopher ward Roger Dixon Phil Winship Institute of Thermofluids School of Mechanical EngineeringUniversity of LeedsLeedsWest YorkshireUK Wolfson School of Mechanical Electrical and Manufacturing EngineeringLoughborough UniversityLoughboroughLeicestershireUK Birmingham Centre for Railway Research and Education School of EngineeringUniversity of BirminghamBirminghamWest MidlandsUK Network Rail Milton KeynesBuckinghamshireUK

The main contribution of this paper is the development and demonstration of a novel methodology that can be followed to develop a simulation twin of a railway track switch system to test the functionality in a digital *** is important because,globally,railway track switches are used to allow trains to change routes;they are a key part of all railway ***,because track switches are single points of failure and safety-critical,their inability to operate correctly can cause significant delays and concomitant *** order to better understand the dynamic behaviour of switches during operation,this paper has developed a full simulation twin of a complete track switch *** approach fuses finite element for the rail bending and motion,with physics-based models of the electromechanical actuator system and the control ***,it provides researchers and engineers the opportunity to explore and understand the design space around the dynamic operation of new switches and switch machines before they are *** is useful for looking at the modification or monitoring of existing switches,and it becomes even more important when new switch concepts are being considered and *** simulation is capable of running in real time or faster meaning designs can be iterated and checked *** paper describes the modelling approach,demonstrates the methodology by developing the system model for a novel“REPOINT”switch system,and evaluates the system level performance against the dynamic performance requirements for the *** the context of that case study,it is found that the proposed new actuation system as designed can meet(and exceed)the system performance requirements,and that the fault tolerance built into the actuation ensures continued operation after a single actuator failure.

关键词： Railway track switch Mathematical modelling Redundant actuation Finite element analysis

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An investigation into intermittent electrification strategies and an analysis of resulting CO_(2) emissions using a high-fidelity train model

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Railway Engineering Science 2021年第3期29卷 314-326页

作者： Bilal M.Abdurahman Tim Harrison christopher P.ward William J.B.Midgley Wolfson School of Mechanical Electrical and Manufacturing EngineeringLoughborough UniversityLoughborough LE113TUUK

A near-term strategy to reduce emissions from rail vehicles,as a path to full electrification for maximal decarbonisation,is to partially electrify a route,with the remainder of the route requiring an additional self-powered traction *** rail vehicles are usually powered by a diesel engine when not operating on electrified track and are referred to as bi-mode *** paper analyses the benefits of discontinuous electrification compared to continuous electrification using the CO_(2)estimates from a validated high-fidelity bi-mode(diesel-electric)rail vehicle *** analysis shows that 50%discontinuous electrification provides a maximum of 54%reduction in operational CO_(2)emissions when compared to the same length of continuously electrified *** highest emissions savings occurred when leaving train stations where vehicles must accelerate quickly to line *** results were used to develop a linear regression model for fast estimation of CO_(2)emissions from diesel running and electrification *** model was able to estimate the CO_(2)emissions from a route to within 10%of that given by the high-fidelity ***,additional considerations such as cost and the embodied CO_(2)in electrification infrastructure were analysed to provide a comparison between continuous and discontinuous *** electrification can cost up to 56%less per reduction in lifetime emissions than continuous electrification and can save up to 2.3 times more lifetime CO_(2)per distance electrified.

关键词： Railway electrification CO_(2)reduction Discontinuous electrification Bi-mode rail vehicle

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The development of Rehabilitation Medicine in Britain

The development of Rehabilitation Medicine in Britain

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中国医师协会第二届康复医学论坛、中国康复医学会第四届青年学术会议、北京康复医学会第三届会员代表大会

作者： christopher D.ward Professor of Rehabilitation Medicine University of Nottingham Consultant in Rehabilitation Medicine Derby Hospitals NHS Trust President-Elect British Society of Rehabilitation Medicine

Prof CD wardDivision of Rehabilitation Medicine Derby City General Hospital Derby DE22 3NE ***@nottingham, .*** would like to begin by thanking Professor Maobin Wang and the other organisers of this meeting for giving me the privilege of talking to you today. I bring the good wishes of my colleagues in our sister organisation, the British Society of Rehabilitation Medicine. I look forward to future dialogues with you since I am certain that we will all be able to serve our patients better if we learn from each other.

关键词： service The development of Rehabilitation Medicine in Britain

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Familial Alzheimer's disease modelling using induced pluripotent stem cell technology

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World Journal of Stem Cells 2014年第2期6卷 239-247页

作者： Lisa Mohamet Natalie J Miazga christopher M ward Stem Cell Biology Group Core Technology FacilityFaculty of Human and Medical SciencesThe University of Manchester

Alzheimer’s disease(AD)is a progressive neurodegenerative disease in which patients exhibit gradual loss of memory that impairs their ability to learn or carry out daily *** of AD is difficult,particularly in early stages of the disease,and largely consists of cognitive assessments,with only one in four patients being correctly *** of novel therapeutics for the treatment of AD has proved to be a lengthy,costly and relatively unproductive process with attrition rates of>90%.As a result,there are no cures for AD and few treatment options available for ***,there is a pressing need for drug discovery platforms that can accurately and reproducibly mimic the AD phenotype and be amenable to high content screening ***,we discuss the use of induced pluripotent stem cells(iPSCs),which can be derived from adult cells,as a method of recapitulation of AD phenotype in *** assess their potential use in high content screening assays and the barriers that exist to realising their full potential in predictive efficacy,toxicology and disease *** present,a number of limitations need to be addressed before the use of iPSC technology can be fully realised in AD therapeutic ***,whilst the use of AD-derived iPSCs in drug discovery remains a fledgling field,it is one with immense potential that is likely to reach fruition within the next few years.

关键词： Human induced pluripotent stem cells Alzheimer’ s disease Neurodegenerative diseases High-throughput screening assays Cholinergic neurons Drug discovery Stratified medicine

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用于降低能耗和控制二氧化碳排放的铁路车辆模型开发与应用

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智慧轨道交通 2023年第4期60卷 85-94页

作者： Tim J Harrison William JB Midgley Roger M Goodall christopher P ward 不详

为助力英国2050年前实现碳中和目标,铁路运输线路将全面实现电气化。这期间,英国应采用其他措施以降低铁路运输碳强度。本文运用MATLAB/Simulink开发了一种Class 800型双模动力列车的详细模型,并根据英格兰西南部全天铁路运行获得的数... 详细信息

为助力英国2050年前实现碳中和目标,铁路运输线路将全面实现电气化。这期间,英国应采用其他措施以降低铁路运输碳强度。本文运用MATLAB/Simulink开发了一种Class 800型双模动力列车的详细模型,并根据英格兰西南部全天铁路运行获得的数据对该模型进行了验证。基于经验证的列车模型分析不同电气化比例线路对二氧化碳排放的影响,及制定降低列车二氧化碳排放的控制措施。结果表明,当列车运行在一条典型线路时,通过自主调节限速控制与发动机选择性关闭相结合的方法可减少二氧化碳排放19.1%。同时,运用该模型调查(间歇性/非连续性)线路电气化排放效率表明,线路全面电气化可使二氧化碳排放量减少66%。

关键词：列车控制双模动力列车二氧化碳能源减排脱碳优化控制

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A general-purpose machine learning framework for predicting properties of inorganic materials

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npj Computational Materials 2016年第1期2卷 70-76页

作者： Logan ward Ankit Agrawal Alok Choudhary christopher Wolverton Department of Materials Science and Engineering Northwestern UniversityEvanstonILUSA Department of Electrical Engineering and Computer Science Northwestern UniversityEvanstonILUSA

A very active area of materials research is to devise methods that use machine learning to automatically extract predictive models from existing materials *** prior examples have demonstrated successful models for some applications,many more applications exist where machine learning can make a strong *** enable faster development of machine-learning-based models for such applications,we have created a framework capable of being applied to a broad range of materials *** method works by using a chemically diverse list of attributes,which we demonstrate are suitable for describing a wide variety of properties,and a novel method for partitioning the data set into groups of similar materials to boost the predictive *** this manuscript,we demonstrate how this new method can be used to predict diverse properties of crystalline and amorphous materials,such as band gap energy and glass-forming ability.

关键词： method properties inorganic

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An experimental study of elastic properties of dragonfly-like flapping wings for use in biomimetic micro air vehicles(BMAVs)

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Chinese Journal of Aeronautics 2017年第2期30卷 726-737页

作者： Praveena Nair Sivasankaran Thomas Arthur ward Erfan Salami Rubentheren Viyapuri christopher J.Fearday Mohd Rafie Johan Department of Mechanical Engineering University of Malaya KuaIa Lumpur 50603 Malaysia School of Engineering and Physical Sciences Heriot-Watt University Malaysia Putrajaya 62200 Malaysia Department of Electrical Engineering University of Malaya Kuala Lumpur 50603 Malaysia

This article studies the elastic properties of several biomimetic micro air vehicle（BMAV）wings that are based on a dragonfly *** are a new class of unmanned micro-sized air vehicles that mimic the flapping wing motion of flying biological organisms（e.g.,insects,birds,and bats）.Three structurally identical wings were fabricated using different materials：acrylonitrile butadiene styrene（ABS）,polylactic acid（PLA）,and *** wing frame structures were fabricated from these materials and then a nanocomposite film was adhered to them which mimics the membrane of an actual *** wings were then attached to an electromagnetic actuator and passively flapped at frequencies of 10-250 Hz.A three-dimensional high frame rate imaging system was used to capture the flapping motions of these wings at a resolution of 320 pixels x 240 pixels and 35000 frames per *** maximum bending angle,maximum wing tip deflection,maximum wing tip twist angle,and wing tip twist speed of each wing were measured and compared to each other and the actual dragonfly *** results show that the ABS wing has considerable flexibility in the chordwise direction,whereas the PLA and acrylic wings show better conformity to an actual dragonfly wing in the spanwise *** studies have shown that the aerodynamic performance of a BMAV flapping wing is enhanced if its chordwise flexibility is increased and its spanwise flexibility is ***,the ABS wing（fabricated using a 3D printer） shows the most promising results for future applications.

关键词： ABS Acrylic Biomimetic micro air vehicle Flapping mechanism PLA Wing structure

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Performance of silver nanoparticles in the catalysis of the oxygen reduction reaction in neutral media： Efficiency limitation due to hydrogen peroxide escape

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Nano Research 2013年第7期6卷 511-524页

作者： christopher C. M. Neumann Eduardo Laborda Kristina Tschulik Kristopher R. ward Richard G. Compton Department of Chemistry Physical and Theoretical Chemistry Laboratory Oxford University South Parks Road Oxford OXl 3QZUnited Kingdom

The electrocatalytic activity for oxygen reduction reaction （ORR） at neutral pH of citrate-capped silver nanoparticles （diameter = 18 nm） supported on glassy carbon （GC） is investigated voltammetrically. Novelly, the modification of the substrate by nanoparticles sticking to form a random nanoparticle array and the voltammetric experiments are carried out simultaneously by immersion of the GC electrode in an air-saturated 0.1 M NaC104 solution （pH = 5.8） containing chemically-synthesized nanoparticles. The experimental voltammograms of the resulting nanoparticle array are simulated with homemade programs according to the two-proton, two-electron reduction of oxygen to hydrogen peroxide where the first electron transfer is rate determining. In the case of silver electrodes, the hydrogen peroxide generated is partially further reduced to water via heterogeneous decomposition. Comparison of the results obtained on a silver macroelectrode and silver nanoparticles indicates that, for the silver nanoparticles and particle coverages （0.035%-0.457%） employed in this study, the ORR electrode kinetics is slower and the production of hydrogen peroxide larger on the glassy carbon-supported nanoparticles than on bulk silver.

关键词： oxygen reduction reaction silver nanoparticles nanoelectrocatalysis hydrogen peroxide escape fuel cells

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Exploring the Spatial Control of Topotactic Phase Transitions Using Vertically Oriented Epitaxial Interfaces

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Nano-Micro Letters 2022年第1期14卷 47-58页

作者： Wenrui Zhang Jie Zhang Shaobo Cheng christopher M.Rouleau Kim Kisslinger Lihua Zhang Yimei Zhu Thomas Z.ward Gyula Eres Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingboZhejiang 315201P.R.China Condensed Matter Physics and Materials Science Brookhaven National LaboratoryUptonNY 11973USA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Center for Functional Nanomaterials Brookhaven National LaboratoryUptonNY 11973USA

Engineering oxygen vacancy formation and distribution is a powerful route for controlling the oxygen sublattice evolution that affects diverse functional *** controlling of the oxygen vacancy formation process is particularly important for inducing topotactic phase transitions that occur by transformation of the oxygen *** we demonstrate an epitaxial nanocomposite approach for exploring the spatial control of topotactic phase transition from a pristine perovskite phase to an oxygen vacancy-ordered brownmillerite(BM)phase in a model oxide La_(0.7)Sr_(0.3)MnO_(3)(LSMO).Incorporating a minority phase NiO in LSMO films creates ultrahigh density of vertically aligned epitaxial interfaces that strongly influence the oxygen vacancy formation and distribution in *** structural characterizations reveal strong interactions between NiO and LSMO across the epitaxial interfaces leading to a topotactic phase transition in LSMO accompanied by significant morphology evolution in *** the NiO nominal ratio as a single control parameter,we obtain intermediate topotactic nanostructures with distinct distribution of the transformed LSMO-BM phase,which enables systematic tuning of magnetic and electrical transport *** use of self-assembled heterostructure interfaces by the epitaxial nanocomposite platform enables more versatile design of topotactic phase structures and correlated functionalities that are sensitive to oxygen vacancies.

关键词： Epitaxial interface Nanocomposite Functional oxides Oxygen vacancy Topotactic phase transition

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Infiltration of Black Carbon Particles from Residential Woodsmoke into Nearby Homes

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Open Journal of Air Pollution 2014年第4期3卷 111-120页

作者： Tracy L. Thatcher Thomas W. Kirchstetter christopher J. Malejan Courtney E. ward Environmental Engineering Department California Polytechnic State University San Luis Obispo CA USA Environmental Energy Technologies Division Lawrence Berkeley National Laboratory Berkeley CA USA

In many communities, residential wood burning is the source of a significant fraction of wintertime PM2.5 and produces exposures to nearby residents inside their homes. To evaluate the magnitude of this effect, black carbon particles were measured as a proxy for woodsmoke indoors and outdoors in a community where residential woodsmoke is the only significant particle source. Thirteen indoor/outdoor measurement pairs were obtained at 4 different residences and showed an average indoor/outdoor concentration ratio of 0.78 ± 0.21 for residences without indoor generation. In addition, a time dependent mass balance model was used in conjunction with aethalometer measurements taken over 16 nights at a single residence to estimate an average air exchange rate of 0.26 ± 0.08 h-1, an average deposition loss rate of 0.08 ± 0.03 h-1, and an average penetration factor of 0.97 ± 0.02. Using a mechanistic approach which utilizes these average values in a steady state model, the predicted average infiltration factor was 0.74 for the residence studied. The high values for both measured I/O ratio and modeled infiltration factor show that residential environments provide inhabitants with relatively little protection from recently generated wood smoke particles.

关键词： I/O Ratio Infiltration Factor Black Carbon Woodsmoke Particles Indoor Exposure

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