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Numerical analysis of high‑speed railway slab tracks using calibrated and validated 3D time‑domain modelling

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Railway Engineering Science 2024年第1期32卷 36-58页

作者： A.F.Esen O.Laghrouche p.K.Woodward D.Medina‑pineda Q.Corbisez J.Y.Shih D.p.Connolly Institute for High‑Speed Rail and System Integration University of LeedsLeeds LS29JTUK Institute for Infrastructure and Environment Heriot-Watt UniversityEdinburgh EH144ASUK Alstom Transport Saint‑OuenFrance Birmingham Centre for Railway Research and Education University of BirminghamBirmingham B152TTUK

Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks,provide safe and smooth rides,and reduce the maintenance *** this paper,the elastic performance of a novel slab trackform for high-speed railways is investigated using three-dimensional finite element modelling in *** is then compared to the performance of a ballasted ***,slab and ballasted track models are developed to replicate the full-scale testing of track *** the models are calibrated with the experimental results,the novel slab model is developed and compared against the calibrated slab track *** slab and ballasted track models are then extended to create linear dynamic models,considering the track geodynamics,and simulating train passages at various speeds,for which the Ledsgard documented case was used to validate the *** travelling at low and high speeds are analysed to investigate the track deflections and the wave propagation in the soil,considering the issues associated with critical *** train loading methods are discussed,and the most practical approach is retained and ***,correlations are made between the geotechnical parameters of modern high-speed rail and conventional *** is found that considering the same ground condition,the slab track deflections are considerably smaller than those of the ballasted track at high speeds,while they show similar behaviour at low speeds.

关键词： High-speed railways Slab track New ballastless track Ballasted track Critical speeds Finite element modelling Calibration of numerical models

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Temperature and structure measurements of heavy-ion-heated diamond using in situ X-ray diagnostics

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Matter and Radiation at Extremes 2024年第4期9卷 80-89页

作者： J.Lutgert p.Hesselbach M.Schorner V.Bagnoud R.Belikov p.Drechsel B.Heuser O.SHumphries p.Katrik B.Lindqvist C.Qu R.Redmer D.Riley G.Schaumann S.Schumacher A.Tauschwitz D.Varentsov K.Weyrich X.Yu B.Zielbauer Zs.Major p.Neumayer D.Kraus Institut fur physik Universitat RostockAlbert-Einstein-Str.2318059 RostockGermany GSI Helmholtzzentrum fur Schwerionenforschung Planckstr.164291 DarmstadtGermany Institut für Angewandte physik Goethe-Universität Frankfurt am MainMax-von-Laue-Str.160438 Frankfurt am MainGermany Institut fur Geowissenschaften Goethe-Universitat Frankfurt am MainAltenhoferallee 160438 Frankfurt am MainGermany Helmholtz-Zentrum Dresden-Rossendorf Bautzner Landstr.40001328 DresdenGermany European XFEL GmbH Holzkoppel 422869 SchenefeldGermany Centre for plasma physics School of Mathematics and PhysicsQueen’s University BelfastUniversity RoadBelfast BT71NNUnited Kingdom Institut für Kernphysik Technische Universität DarmstadtSchlossgartenstr.964289 DarmstadtGermany State Key Laboratory of Nuclear physics and Technology Institute of Heavy Ion PhysicsPeking UniversityBeijing 100871China Helmholtz Institut Jena Frobelstieg 307743 JenaGermany

We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heatedwith an intense pulse of heavy *** this way,we determine the samples’heating dynamics and their microscopic and macroscopic structuralintegrity over a timespan of several *** the ratio of elastic to inelastic scattering with state-of-the-art density functionaltheory molecular dynamics simulations allows the inference of average temperatures around 1300 K,in agreement with predictions fromstopping power *** simultaneous diffraction measurements show no hints of any volumetric graphitization of the material,butdo indicate the onset of fracture in the diamond *** experiments pave the way for future studies at the Facility for Antiproton andIon Research,where a substantially increased intensity of the heavy ion beam will be available.

关键词： heated intense structure

Wettability,reactivity,and interface structure in Mg/Ni system

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Journal of Magnesium and Alloys 2024年第2期12卷 659-672页

作者： S.Terlicka N.Sobczak Ł.Maj p.Darłak J.J.Sobczak Institute of Metallurgy and Materials Science Polish Academy of Sciences25 Reymonta Str.KrakowPoland Faculty of Foundry Engineering AGH University23 Reymonta Str.KrakowPoland

The sessile drop method was applied to the experimental investigation of the wetting and spreading behaviors of liquid Mg drops on pure Ni *** comparison,the experiments were performed in two variants:(1)using the Capillary purification(Cp)procedure,which allows the non-contact heating and squeezing of a pure oxide-free Mg drop;(2)by classical Contact Heating(CH)*** high-temperature tests were performed under isothermal conditions(Cp:760℃for 30 s;CH:715℃for 300 s)using Ar+5 wt%H_(2) *** the sessile drop tests,images of the Mg/Ni couples were recorded by CCD cameras(57 fps),which were then applied to calculate the contact angles of metal/substrate *** and transmission electron microscopy analyses,both coupled with energy-dispersive X-ray spectroscopy,were used for detailed structural characterization of the solidified *** was found that an oxide-free Mg drop obtained by the Cp procedure showed a wetting phenomenon on the Ni substrate(an average contact angleθpreading and good wetting over the Ni substrate(θ_((Cp))~20°in 5 s)to form a final contact angle ofθ_(f(Cp))~18°.In contrast,a different wetting behavior was observed for the CH procedure,where the unavoidable primary oxide film on the Mg surface blocked the spreading of liquid Mg showing apparently non-wetting behavior after 300 s contact at the test ***,in both cases,the deep craters formed in the Ni substrates under the Mg drops and significant change in the structure of initially pure Mg drops to Mg-Ni alloys suggest a strong dissolution of Ni in liquid Mg and apparent values of the final contact angles measured for the Mg/Ni system.

关键词： Magnesium-based alloys Sessile drop tests Capillary purification procedure Wettability Reactivity Contact angle

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Selection of shaped charges parameters for producing aluminum particles with velocities in the range of 2.5-16 km/s

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Defence Technology（防务技术） 2024年第8期38卷 126-135页

作者： Vladimir I.Kolpakov Sergey V.Fedorov Ekaterina p.Vinogradova Irina A.Bolotina Bauman Moscow State Technical University Moscow 105005Russia

Testing rocket and space technology objects in ground conditions for resistance to the impact of meteoroids and fragments of space debris can be carried out using shaped charges. To substantiate the design parameters of shaped charges that ensure the formation of aluminum particles in a wide velocity range(from 2.5 to 16 km/s), numerical modeling of the formation process was carried out within the framework of a two-dimensional axisymmetric problem of continuum mechanics using three different computing codes to increase the reliability of the results. The calculations consider shaped charges with a diameter of 20-100 mm with aluminum liners of various shapes. It is shown that the formation of particles with velocities close to the lower limit of the considered range is ensured by gently sloping segmental liners of degressive thickness. To form higher-velocity particles with velocities over 5 km/s, it is proposed to use combined liners, the jet-forming part of which has the shape of a hemisphere of constant thickness or the shape of a semi-ellipsoid or semi-superellipsoid of rotation of degressive thickness.

关键词： Space debris Meteoric impact Explosion Shaped charge High-velocity aluminum element Segmental liner Combined liner Numerical simulation

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A flexible,thin-film microchannel electrode array device for selective subdiaphragmatic vagus nerve recording

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Microsystems & Nanoengineering 2024年第1期10卷 115-128页

作者： Jongcheon Lim peter A.Zoss Terry L.powley Hyowon Lee Matthew p.Ward Weldon School of Biomedical Engineering Purdue UniversityWest LafayetteINUSA Birck Nanotechnology Center Purdue UniversityWest LafayetteINUSA Center for Implantable Devices Purdue UniversityWest LafayetteINUSA Department of psychological Sciences Purdue UniversityWest LafayetteINUSA purdue Institute of Integrative Neuroscience Purdue UniversityWest LafayetteINUSA Indiana University School of Medicine IndianapolisINUSA

The vagus nerve(VN)plays an important role in regulating physiological conditions in the gastrointestinal(GI)tract by communicating via the parasympathetic pathway to the enteric nervous system(ENS).However,the lack of knowledge in the neurophysiology of the VN and GI tract limits the development of advanced treatments for autonomic dysfunctions related to the *** better understand the complicated underlying mechanisms of the VN-GI tract neurophysiology,it is necessary to use an advanced device enabled by microfabrication *** several candidates including intraneural probe array and extraneural cuff electrodes,microchannel electrode array devices can be used to interface with smaller numbers of nerve fibers by securing them in the separate channel *** microchannel electrode array devices to interface teased nerve structures are relatively bulky with thickness around 200µ*** thick design can potentially harm the delicate tissue structures,including the nerve *** this paper,we present a flexible thin film based microchannel electrode array device(thickness:11.5µm)that can interface with one of the subdiaphragmatic nerve branches of the VN in a *** demonstrated recording evoked compound action potentials(ECAp)from a transected nerve ending that has multiple nerve ***,our analysis confirmed that the signals are from C-fibers that are critical in regulating autonomic neurophysiology in the GI tract.

关键词： electrode recording film

Multi-scale habitat influences sprainting and group size of a freshwater-obligate smooth-coated otter(Lutrogale perspicillata) in Tungabhadra Otter Conservation Reserve, India

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Ecological processes 2024年第1期13卷 159-175页

作者： Ankit Moun p.Ramesh Kumar M.Malathi priya T.Ramesh Riddhika Kalle Sálim Ali Centre for Ornithology and Natural History Deputy Conservator of Forests Bellary Territorial Forest Division Deputy Conservator of Forests Working Plan and Survey and Research WingBellary Territorial Forest Division Centre for Functional Biodiversity University of Kwa Zulu-Natal

Background The impact of changing land-use patterns and associated anthropogenic threats on scale-dependent habitat use of semi-aquatic mustelids in scent-marking and social behaviour can provide important insights into the habitat ecology of smooth-coated otters(Lutrogale perspicillata).Methods We sampled 180 stream segments(100–400 m) as spatial replicates of 60 1-km2 sites to record indirect evidence(i.e. spraints and mass latrine sites) and group sizes of smooth-coated otters along the Tungabhadra Otter Conservation Reserve(TOCR) during the dry season. To quantify habitat, we recorded stream characteristics, riparian vegetation, and anthropogenic disturbances at the local scale, and hydro-environmental characteristics and land uses at the landscape scale. Using Markovian-chain detection and occupancy models, we assessed the multi-scale habitat use of otters in their selection of suitable areas for scent-marking based on repeated presence-absence data on spraint/latrine locations along the TOCR. We further used linear regression techniques to explore relationships between the number of individuals in smooth-coated otter group and hydro-environmental characteristics, spraint/latrine encounter rate, anthropogenic pressure, land cover, topography, and *** At the local scale, the probability of spraint deposition and group size decreased with anthropogenic disturbance while the probability of spraint detections decreased with grass cover. At the landscape scale, the probability of otter site use for spraint deposition and group sizes increased in southeast flowing streams. Spraint deposition increased with the proportion of sugarcane fields, whereas in contrast, group size decreased with proportion of sugarcane *** Our findings highlight the first empirical evidence on multi-scale habitat use of a southern Indian population of smooth-coated otters in an inland freshwater ecosystem surrounded by the scrub jungle–agriculture matrix. We sug

关键词： presence-absence modelling Inland river Freshwater ecosystem Semi-aquatic mammal Smooth-coated otter

The potential of glutamine supplementation in reduced-crude protein diets for chicken-meat production

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Animal Nutrition 2024年第3期18卷 49-56页

作者： peter H.Selle Shemil p.Macelline Mehdi Toghyani Sonia Yun Liu poultry Research Foundation within the University of Sydney CamdenNSW 2570Australia Sydney School of Veterinary Science The University of SydneyCamdenNSW 2570Australia School of Life and Environmental Sciences Faculty of ScienceThe University of SydneyCamdenNSW 2570Australia

This review explores the potential of including glutamine,a so-called non-essential amino acid,in the formulation of reduced-crude protein(Cp)diets for broiler *** is a precedent for benefits when including glycine and serine in reduced-Cp *** this is due to decreases in non-essential amino acid concentrations in reduced-Cp diets—an unavoidable consequence of reducing Cp without amino acid *** situation for glutamine is complicated because analysed dietary concentrations are very rarely provided as standard assays do not differentiate between glutamine and glutamate and are reported on a combined basis as glutamic *** dietary requirement for glutamic acid is approximately 36.3 g/kg but it is increasingly unlikely that this requirement will be met as dietary Cp levels are progressively *** is an abundant and versatile amino acid and constitutes 50.5 mg/g of whole-body chicken protein and is the dominant free amino acid in systemic plasma where it has been shown to provide 22.6%(139.9 of 620.3μg/mL)of the total in birds offered 215 g/kg Cp,wheat-based *** addition to dietary intakes,glutamine biosynthesis is derived mainly from the condensation of glutamate and ammonia(NH3)catalysed by glutamine synthetase,a reaction that is pivotal to NH3 *** and NH3 are converted to glutamine by phosphate-dependent glutaminase in the reciprocal reaction;thus,glutamine and glutamate are interchangeable amino ***,the rate of glutamine biosynthesis may not be adequate in rapidly growing broiler chickens and exogenous and endogenous glutamine levels are probably insufficient in birds offered reduced-Cp *** many functional roles of glutamine,including NH3 detoxification and maintenance of acid-base homeostasis,then become *** feeding studies were identified where dietary glutamine supplementation,usually 10 g/kg,was evaluated in birds kept under thermoneutral ***

关键词： Broiler chicken Glutamate Glutamic acid Glutamine

Simulation and experimentation of propeller-Savonius turbine tested underwater surface

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Clean Energy 2024年第3期8卷 20-33页

作者： Sri Wuryanti Teguh Sasono Bambang p.Manunggal Wahyu B.Mursanto Sugianto Department of Energy Conversion Engineering Politeknik Negeri BandungIndonesia Department of Mechanical Engineering Politeknik Negeri BandungIndonesia

Indonesia’s vast maritime territory offers a unique opportunity for harnessing the potential Energy of seawater *** study explores the effectiveness of a combined Savonius and propeller-type turbine *** Savonius turbine,known for its efficiency in capturing ocean currents due to its large sweep area,is combined with a propeller-type turbine to enhance rotational speed and power generation.A novel approach is employed to induce turbulence and optimize energy extraction,first channeling water through the propeller turbine and then into the Savonius turbine.A comprehensive investigation is conducted through simulations and experimental tests within a controlled tunnel *** study explores the performance of two-bladed and three-bladed propeller-Savonius configurations at varying inlet water velocities(0.1,0.3,0.6 and 1.0 m/s).The simulation incorporates a turbulence model with 5%intensity and a hydraulic diameter of 0.216 *** indicate that the proposed configuration achieves a maximum power output of 2.0293 W with an impressive efficiency of 63.339%in ***,experimental testing yields a peak efficiency of 61.335%and turbine power of 0.3951 *** findings demonstrate the feasibility of the combined turbine system and highlight the importance of turbulence in optimizing energy extraction from seawater *** research contributes valuable insights into the design and performance of hybrid turbines for harnessing oceanic Energy,emphasizing the potential for sustainable power generation in maritime *** methodology and results presented herein offer a foundation for further exploration and refinement of seawater current energy conversion technologies.

关键词： hydro-turbine propeller-Savonius renewable energy water

Does enhanced recovery after surgery programs improve clinical outcomes in liver cancer surgery?

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World Journal of Gastrointestinal Oncology 2024年第2期16卷 255-258页

作者： Belinda Sánchez-pérez JoséM Ramia Department of General Digestive and Transplantation SurgeryUniversity Regional HospitalMálaga 29010MálagaSpain Department of Surgery Hospital General Universitario Dr.BalmisAlicante 03010Spain

Enhanced recovery after surgery(ERAS)programs have been widely applied in liver surgery since the publication of the first ERAS guidelines in 2016 and the new recommendations in *** surgery is usually performed in oncological patients(liver metastasis,hepatocellular carcinoma,cholangiocarcinoma,etc.),but the real impact of liver surgery ERAS programs in oncological outcomes is not clearly *** advantages of ERAS programs are:ERAS decreases postoperative complication rates and has been demonstrated a clear relationship between complications and oncological outcomes;a better and faster posto-perative recovery should let oncologic teams begin chemotherapeutic regimens on time;prehabilitation and nutrition actions before surgery should also improve the performance status of the patients receiving ***,ERAS could be another way to improve our oncological *** will discuss the literature about liver surgery ERAS focusing on its oncological implications and future investigations projects.

关键词： Enhanced recovery after surgery programs Liver surgery Key components Long-term oncological outcomes Enhanced recovery after surgery compliance