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Influence of railway wheel tread damage on wheel-rail impact loads and the durability of wheelsets

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Railway Engineering Science 2024年第1期32卷 20-35页

作者： Michele Maglio Tore Vernersson Jens C.o.Nielsen Anders Ekberg Elena Kabo CHARMEC Department of Mechanical and Maritime SciencesChalmers University of TechnologySE‑41296 GothenburgSweden

Dynamic wheel-rail contact forces induced by a severe form of wheel tread damage have been measured by a wheel impact load detector during full-scale field tests at different vehicle *** on laser scanning,the measured three-dimensional damage geometry is employed in simulations of dynamic vehicle-track interaction to calibrate and verify a simulation *** relation between the magnitude of the impact load and various operational parameters,such as vehicle speed,lateral position of wheel-rail contact,track stiffness and position of impact within a sleeper bay,is *** calibrated model is later employed in simulations featuring other forms of tread damage;their effects on impact load and subsequent fatigue impact on bearings,wheel webs and subsurface initiated rolling contact fatigue of the wheel tread are *** results quantify the effects of wheel tread defects and are valuable in a shift towards condition-based maintenance of running gear,and for general assessment of the severity of different types of railway wheel tread damage.

关键词： Wheel tread damage Rolling contact fatigue cluster Field measurements Dynamic vehicle-track interaction Wheel-rail impact load Wheelset durability

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Are dogs not susceptible to retroviral infections?

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Animal Diseases 2024年第3期4卷 217-223页

作者： Jorge Casseb João Henrique Campos Luciano Rodrigo Lopes Laboratory of Investigation in Dermatology and Immunodefciencies Department of DermatologyUniversity of São Paulo Medical SchoolSão PauloSPBrazil Igen-Institute of Immunogenetics São PauloSPBrazil Bioinformatics and Biomedical Data Science Division Health Informatics DepartmentUniversidade Federal de São Paulo–UNIFESP.Rua Botucatu 862Prédio Leal PradotérreoVila ClementinoCEP 04023-062São PauloSPBrazil

Retroviruses have been proven to cause infections and diseases in a series of mammalian hosts but not in ***,this letter discussed the dog susceptibility to retrovirus infection,encompassing arguments to understand why dogs may have not been infected by retroviruses thus *** potential resistance of retrovirus in dogs enables this provocative short communication to discuss this question,looking at some evolutive *** lineage of canids has shown,throughout its evolutionary history,a smaller accumulation of retroviruses in canid genomes,classifed as endogenous *** this context,the genomes of canids seem to ofer obstacles,which have been evolutionarily conserved,in the face of retroviral infection.

关键词： Retrovirus dogs Endogenous retrovirus

A hybrid solar-biogas system for post-CoVID-19 rural energy access

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Clean Energy 2024年第1期8卷 84-99页

作者： ochuko K.overen KeChrist obileke Edson L Meyer Golden Makaka oliver o.Apeh Fort Hare Institute of Technology University of Fort HarePrivate Bag X1314Alice 5700South Africa Department of Physics Renewable Energy Research CentreUniversity of Fort HarePrivate Bag X1314Alice 5700South Africa Department of Electrical and Electronic Engineering Science Faculty of Engineering and Build EnvironmentUniversity of JohannesburgAuckland Park 2006South Africa

Solar home systems for rural electrification are often designed with a limited energy supply,which presents a drawback for the ***,uncontrolled livestock faeces in rural communities constitute environmental sanitation and health *** excrement can be used through a biogas digester to supplement solar energy to provide adequate and sustainable elec-tricity access to underserved rural communities while achieving waste ***,this study presents a hybrid solar-biogas system for a more dynamic energy supply and waste management for post-Covid recovery plans in rural communities.A parametric research approach that involves the use of the Integrated Environment Solution Virtual Environment software application and mathematical models to design the desired household load and the hybrid system sizing is used in the *** findings show that the daily household energy consumption was 6.6 kWh,equivalent to 206.40 kWh/month.A 1.2-kWp and 1.2-m^(3)hybrid solar-biogas system was found to adequately power the ***,the total initial investment cost of the system was$5777.20 with a net present value of$6566.78,net profit of$4443.6,a payback period of 14 years and 8 months,and a levelized cost of energy of$0.21/kWh;these include a 60%initial investment and maintenance costs *** performance contracting and energy-as-a-service were recommended to effectively run and operate the *** study successfully revealed the design,specifications and upscaling mechanism of the proposed hybrid solar-biogas *** research is required to unveil the efficacy of the system,the performance gap and the perception of the technology by the beneficiaries.

关键词： energy access sustainable rural development clean energy waste management post-CoVID-19 recovery plan

optimization of bio-oil production parameters from the pyrolysis of elephant grass (Pennisetum purpureum) using response surface methodology

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Clean Energy 2024年第5期8卷 241-251页

作者： Sunday C.Ikpeseni Samuel o.Sada Ufuoma J.Efetobor Henry o.orugba Mathias Ekpu Hilary I.owamah Jeremiah L.Chukwuneke Solomon oyebisi Uche P.onochie Department of Mechanical Engineering Delta State UniversityP.M.B.1AbrakaNigeria Department of Mechanical Engineering Delta State PolytechnicP.M.B.3Otefe-OgharaNigeria Department of Chemical Engineering Delta State UniversityP.M.B.1AbrakaNigeria Department of Civil Engineering Delta State UniversityP.M.B.1AbrakaNigeria Department of Mechanical Engineering Nnamdi Azikiwe UniversityP.M.B.2025AwkaNigeria Department of Civil Engineering Covenant UniversityP.M.B.1023OttaNigeria Department of Civil Engineering The University of the South PacificP.M.B.9072SuvaFiji Department of Mechanical Engineering Delta State University of Science and TechnologyP.M.B.5OzoroNigeria

The need to increase bio-oil yield from biomass and enhance its fuel properties has driven research into optimizing the pyrolysis *** study investigated the influence of three key process parameters—temperature,heating rate,and nitrogen flow rate—on the pyrolysis of elephant grass(Pennisetum purpureum)in a fixed-bed *** surface methodology was used to study the im-pact of the aforementioned variables on bio-oil yield to improve its production *** analysis of the biomass revealed 79.24 wt%volatile matter,14.22 wt%fixed carbon,and 5.86%ash,with ultimate analysis showing 45.44%carbon,5.59%hydrogen,and 40.95%*** high volatile matter content and favourable carbon and hydrogen percentages indicate that elephant grass is a vi-able energy source due to its potential for high bio-oil yield and energy *** resulting bio-oil exhibited a higher heating value of 20.9 MJ/kg,indicating its suitability for various heating applications.A second-order regression model was developed for bio-oil yield,with optimal conditions identified as a temperature of 550°C,a heating rate of 17°C/min,and a nitrogen flow rate of 6 ml/*** study achieved an optimal bio-oil yield of 59.03 wt%,and the model’s high R²value of 0.8683 from analysis of variance analysis confirmed its predictive *** research highlights elephant grass as a sustainable feedstock for bio-oil production,offering valuable insights into optimizing pyrolysis conditions to enhance bio-oil yield,thus advancing biofuel technology.

关键词： renewable energy biomass sustainable feedstock regression model fixed-bed reactor

A decomposition of light’s spin angular momentum density

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Light(Science & Applications) 2024年第8期13卷 1578-1589页

作者： Alex J.Vernon Sebastian Golat Claire Rigouzzo Eugene A.Lim Francisco J.Rodríguez-Fortuño Department of Physics King’s College LondonStrandLondon WC2R 2LSUK London Centre for Nanotechnology LondonUK

Light carries intrinsic spin angular momentum(SAM)when the electric or magnetic field vector rotates over time.A familiar vector equation calculates the direction of light’s SAM density using the right-hand rule with reference to the electric and magnetic polarisation *** Maxwell’s equations,this vector equation can be decomposed into a sum of two distinct terms,akin to the well-known Poynting vector decomposition into orbital and spin *** present the first general study of this spin decomposition,showing that the two terms,which we call canonical and Poynting spin,are chiral analogies to the canonical and spin momenta of light in its interaction with *** canonical momentum,canonical spin is directly *** canonical and Poynting spin incorporate spatial variation of the electric and magnetic fields and are influenced by optical *** decomposition allows us to show that a linearly polarised vortex beam,which has no total SAM,can nevertheless exert longitudinal chiral pressure due to equal and opposite canonical and Poynting spins.

关键词： canonical momentum angular

Elucidating the Degradation Pathways of Human Insulin in the Solid State

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Journal of Analysis and Testing 2024年第3期8卷 288-299页

作者： Andrew Fagan Lorraine M.Bateman Joseph P.o'Shea Abina M.Crean SSPC the SFI Centre for Pharmaceutical Research School of Pharmacy University College Cork School of Pharmacy University College Cork Analytical and Biological Chemistry Research Facility (ABCRF) University College Cork School of Chemistry University College Cork

While there have been significant advances in the development of peptide oral dosage forms in recent years, highlighted by the clinical and commercial success of approved peptides such as Rybelsus?, there remain several barriers in the way of broad range applicability of this approach to peptide delivery. one such barrier includes the poor physical and chemical stability inherent to their structures, which persists in the solid state although degradation typically occurs at different rates and via different pathways in comparison to the solution state. Using insulin as a model peptide, this work sought to contribute to the development of analytical techniques for investigating common insulin degradation pathways. Chemically denatured,deamidated and aggregated samples were prepared and used to benchmark circular dichroism spectroscopy, reverse phase HPLC and size exclusion chromatography methods for the investigation of unfolding, chemical modifications and covalent aggregation of the insulin molecule respectively. Solid state degraded samples were prepared by heating insulin powder at 60 °C and 75% relative humidity for 1, 3, 5 and 7 d, and the degradation profiles of the samples were evaluated and compared with those observed in solution. While no unfolding was observed to occur, significant deamidation and covalent aggregation were detected. Reductive disulfide bond cleavage using dithiothreitol allowed for separation of the insulin A-and B-chains,offering a facile yet novel means of assessing the mechanisms of deamidation and covalent aggregation occurring in the solid state.

关键词： Biopharmaceutical analysis Covalent aggregation Deamidation Disulfide cleavage Insulin Solid state Stability

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近代中国武术“学科意识”的觉醒

西安体育学院学报 2024年第2期41卷 261-270页

作者：刘红军白俊亚戴国斌上海政法学院警务学院上海201701 邯郸学院太极文化学院邯郸056005 上海体育大学武术学院上海200438

在近代学术转型背景下产生的分科治学思想,重组了武术知识,形塑了近代武术的学科意识。作为对学科的认识与理解,武术的学科意识在近代学术转型与分科治学背景下,借助报刊、议决案反复言说与教育活动的不断实践,在尝试将武术知识推介为... 详细信息

在近代学术转型背景下产生的分科治学思想,重组了武术知识,形塑了近代武术的学科意识。作为对学科的认识与理解,武术的学科意识在近代学术转型与分科治学背景下,借助报刊、议决案反复言说与教育活动的不断实践,在尝试将武术知识推介为教学内容的过程中,激发了武术由教学而学术的知识转型。在武术知识转型中,在中央与地方的学科认知互动中,在解纾学科建构之困中,在由教学而学术的转捩中,武术的学科意识逐渐觉醒。近代武术学科意识的觉醒,使武术知识获得新的书写方式,成为学校体育中的重要一环,折射出了西风东渐之后国人的文化自觉,也为当前民族传统体育的中国式现代化发展提供历史经验。

关键词：武术学科学科意识学科体系

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Evaluation of Mechanical Properties and Surface Quality of Wood from Bosnia and Herzegovina Exposed to outdoor Conditions

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Journal of Renewable Materials 2024年第8期12卷 1417-1431页

作者： Redžo Hasanagić UmejrŠljivo Leila Fathi Pallavi Gautam Mohsen Bahmani Miha Humar Department of Wood Science and Technology Faculty of Technical EngineeringUniversity of BihaćBihać77000Bosnia and Herzegovina Department of Wood and Furniture Industry Engineering Faculty of Resources and Earth ScienceShahrekord UniversityShahrekord64165478Iran Department of Botany Institute of ScienceBanaras Hindu UniversityVaranasiUttar Pradesh221005India Biotechnical Faculty Department of Wood ScienceUniversity of LjubljanaLjubljana1501Slovenia

This study investigated the mechanical properties of beech(Fagus sylvatica L.)and fir(Abies alba)wood from Bosnia and Herzegovina under outdoor *** were exposed for 3-month exposure to assess bending strength,color changes,and surface *** showed outdoor exposure negatively affected mechanical properties,particularly in samples with extended finger joints,causing significant surface cracks in uncoated *** wood exhibited notable color changes under exposure,with approximately 50%darkening without coating compared to 25%under covered *** samples displayed minimal color changes,affirming the efficacy of surface *** wood exhibited a roughness of 8.264μm,while beechwood average roughness increased from 6.767 to 13.916μm after exposure,with micro-pore development affecting water *** analysis identified prevalent fungal colonies,including Penicillium,Aureobasidium,Sclerophoma,and Chaetomium,underscoring their role in organic matter *** study highlights the importance of wood exposure and treatment selection for various applications.

关键词： Mechanical properties outdoor conditions cracks wood species

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胶原交联的改性研究进展（二）

西部皮革 2024年第15期46卷 12-19页

作者：曾俊雅成都科乐金生物科技有限责任公司科乐金生物胶原类再生与重建复合医用材料工程研究中心

胶原蛋白作为一种在各类结缔组织中广泛存在的重要结构蛋白，其独特的三螺旋结构和形成交联网络的能力，为其提供了显著的机械强度和耐久性。通过不同的交联方法，特别是化学交联，可以显著改善胶原蛋白的物理和化学性质，从而拓宽其在... 详细信息

胶原蛋白作为一种在各类结缔组织中广泛存在的重要结构蛋白，其独特的三螺旋结构和形成交联网络的能力，为其提供了显著的机械强度和耐久性。通过不同的交联方法，特别是化学交联，可以显著改善胶原蛋白的物理和化学性质，从而拓宽其在医学、食品工业、环保和化妆品等领域的应用范围。各种交联剂，包括戊二醛、EDC/NHS体系、酚酸、京尼平以及纳米粒子等，均显示出增强胶原蛋白力学性能、热稳定性和抗酶降解能力的潜力。这些性能的提升，为胶原蛋白基材料的生物医学应用，如血管移植、软骨修复、器官再生、角膜修复以及在食品包装和保湿化妆品中的应用，提供了重要支持。

关键词：胶原交联改性医学应用胶原基材料