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Cryogenic and conventional milling of AZ91 magnesium alloy

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Journal of Magnesium and Alloys 2024年第6期12卷 2503-2519页

作者： Vikas Marakini Srinivasa pai p Gururaj Bolar Bhaskara p Achar Department of Mechanical Engineering Nitte(Deemed to be University)NMAM Institute of Technology(NMAMIT)Nitte 574110India Department of Mechanical and Industrial Engineering Manipal Institute of TechnologyManipal Academy of Higher EducationManipal 576104India

Use of magnesium is the need of the hour due to its low density as well as its high strength-to-weight and stiffness-to-weight ratio *** study focuses on the effectiveness of liquid nitrogen(LN_(2))assisted cryogenic machining on the surface integrity(SI)characteristics of AZ91 magnesium *** milling using uncoated carbide inserts have been performed under liquid nitrogen(LN_(2))assisted cryogenic condition and compared with conventional(dry)*** are performed using machining parameters in terms of cutting speeds of 325,475,625 m/min,feed rates of 0.05,0.1,0.15 mm/teeth and depth of cuts of 0.5,1,1.5 mm *** significant surface integrity characteristics such as surface roughness,microhardness,microstructure,and residual stresses have been *** of SI characteristics with respect to milling parameters have been identified using statistical technique such as ANOVA and signal-to-noise(S/N)ratio ***,the multi criteria decision making(MCDM)techniques such as additive ratio assessment method(ARAS)and complex proportional assessment(COpRAS)have been utilized to identify the optimal conditions for milling AZ91 magnesium alloy under both dry and cryogenic *** of LN_(2)during machining,resulted in reduction in machining temperature by upto 29%with a temperature drop from 251.2℃under dry condition to 178.5℃in cryogenic *** showed the advantage of performing cryogenic milling in improving the surface integrity to a significant *** machining considerably minimized the roughness by upto 28%and maximised the microhardness by upto 23%,when compared to dry *** speed has caused significant impact on surface roughness(95.33%-dry,92.92%-cryogenic)and surface microhardness(80.33%-dry,82.15%-cryogenic).Due to the reduction in machining temperature,cryogenic condition resulted in compressive residual stresses(maximumσ║=-113 Mpa)on the alloy *** indicate no

关键词： Magnesium alloy Cryogenic machining Roughness Microhardness Microstructure Residual stress Multi criteria decision making

*** model of riboflavin transporter deficiency(RTD)disorder reveals deficits in synaptic transmission and movement

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Genes & Diseases 2024年第4期11卷 120-123页

作者： Ramesh k.Narayanan Gonzalo perez-siles kamila A.Marzec Alexandra Boyling Brent Neumann Manoj p.Menezes Marina L.kennerson Northcott Neuroscience Laboratory ANZAC Research Institute-Sydney Local Health DistrictSydneyNSW 2139Australia Sydney Medical School University of SydneySydneyNSw 2050Australia ANZAC Research Institute-Sydney Local Health District SydneyNSW 2139Australia Neuroscience program Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental BiologyMonash UniversityMelbourneVictoria 3800Australia TY Nelson Department of Neurology and Neurosurgery and kids Neuroscience Children's Hospital at WestmeadWestmeadSydneyNSW2145Australia paediatrics and Child Health The University of SydneySydneySydneyNSW 2145Australia Molecular Medicine Laboratory Concord General Repatriation HospitalSydneyNSW 2139Australia

Riboflavin transporter deficiency(RTD),previously known as Brown-Vialetto-Van Laere syndrome,is a childhoodonset neurodegenerative disorder characterized by sensory and motor neuron degeneration causing ataxia,muscle weakness,optic atrophy,and respiratory *** in SLC52A2 and SLC52A3,solute carrier family members that encode riboflavin(RF)transporters RFVT2 and RFVT3,are known to cause RTD types 2 and 3,respectively.

关键词： RTD degeneration TD

Risk of hepatitis B virus reactivation in cancer patients undergoing treatment with tyrosine kinase-inhibitors

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World Journal of Gastroenterology 2024年第24期30卷 3052-3058页

作者： Bansi p Savaliya Ramin Shekouhi Fatima Mubarak Harsheen k Manaise paola Berrios Jimenez Gabrielle kowkabany Reed A popp kyle popp Emmanuel Gabriel Department of Surgery Medical Academy Named after SI Georgievsky of Vernadsky Crimean Federal UniversitySimferopol 295015CrimeaRussia Division of plastic and Reconstructive Surgery Department of SurgeryUniversity of FloridaGainesvilleFL 32608United States Department of Surgery Aga Khan UniversityKarachi 74800SindhPakistan Department of Surgery Government Medical College and HospitalChandigarh 160030PunjabIndia Department of Surgery University of Puerto Rico School of MedicineSan Juan 00921Puerto Rico Department of Chemical and Biological Engineering University of AlabamaTuscaloosaAL 35487United States Department of Surgery University of Florida College of MedicineGainesvilleFL 32610United States Department of Surgery Florida State UniversityTallahasseeFL 32306United States Department of Surgery Mayo ClinicJacksonvilleFL 32224United States

This editorial commented on an article in the World Journal of Gastroenterology titled“Risks of Reactivation of Hepatitis B Virus in Oncological patients Using Tyrosine kinase-Inhibitors:Case Report and Literature Analysis”by Colapietro et *** this editorial,we focused on providing a more comprehensive exploration of hepatitis B virus reactivation(HBVr)associated with the usage of tyrosine kinase inhibitors(TkIs).It includes insights into the mechanisms underlying HBV reactivation,the temporal relationship between TkIs and HBV reactivation,and preventive *** aim is to understand the need for nucleos(t)ide analogs(NAT)and serial blood tests for early recognition of reactivation and acute liver injury,along with management *** are considered to be an intermediate(1%-10%)of *** guidelines stipulate that patients receiving therapy with high or moderate risks of reactivation or recent cancer diagnosis must have at least tested hepatitis B surface antigen,anti-hepatitis B core antigen(HBc),and anti-hepatitis B surface ***-HBc screening in highly endemic areas means people with negative tests should be vaccinated against *** or nucleotide analogs(NAs)like entecavir(ETV),tenofovir disoproxil fumarate(TDF),and tenofovir alafenamide(TAF)form the basis of HBV reactivation prophylaxis and treatment during ***,lamivudine,telbivudine,and adefovir are generally discouraged due to their reduced antiviral efficacy and higher risk of fostering drug-resistant viral ***,these less effective NAs may still be utilized in cases where ETV,TDF,and TAF are not feasible treatment options.

关键词： Hepatitis B virus Reactivation Chronic hepatitis B Tyrosine-kinase inhibitor Immunomodulators Immunosuppressant Nucleoside analogue Hemato-oncology

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

Modal Frequency prediction of Chladni patterns Using Machine Learning

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Open Journal of Acoustics 2024年第1期12卷 1-16页

作者： Atul kumar k. p. Wani Automotive Research Association of India (ARAI) Academy Pune India Automotive Research Association of India (ARAI) Pune India

The introduction of machine learning (ML) in the research domain is a new era technique. The machine learning algorithm is developed for frequency predication of patterns that are formed on the Chladni plate and focused on the application of machine learning algorithms in image processing. In the Chladni plate, nodes and antinodes are demonstrated at various excited frequencies. Sand on the plate creates specific patterns when it is excited by vibrations from a mechanical oscillator. In the experimental setup, a rectangular aluminum plate of 16 cm x 16 cm and 0.61 mm thickness was placed over the mechanical oscillator, which was driven by a sine wave signal generator. 14 Chladni patterns are obtained on a Chladni plate and validation is done with modal analysis in Ansys. For machine learning, a large number of data sets are required, as captured around 200 photos of each modal frequency and around 3000 photos with a camera of all 14 Chladni patterns for supervised learning. The current model is written in python language and model has one convolution layer. The main modules used in this are Tensor Flow keras, Numpy, CV2 and Maxpooling. The fed reference data is taken for 14 frequencies between 330 Hz to 3910 Hz. In the model, all the images are converted to grayscale and canny edge detected. All patterns of frequencies have an almost 80% - 99% correlation with test sample experimental data. This approach is to form a directory of Chladni patterns for future reference purpose in real-life application. A machine learning algorithm can predict the resonant frequency based on the patterns formed on the Chladni plate.

关键词： Chaldni pattern Modal Analysis Machine Learning Resonant Frequency Image processing

Direct scaling of residual displacements for bilinear and pinching oscillators

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 129-149页

作者： Mohammad Saifullah Vinay k.Gupta Department of Civil Engineering Indian Institute of Technology KanpurKanpur 208016India

The estimation of residual displacements in a structure due to an anticipated earthquake event has increasingly become an important component of performance-based earthquake engineering because controlling these displacements plays an important role in ensuring cost-feasible or cost-effective repairs in a damaged structure after the *** attempt is made in this study to obtain statistical estimates of constant-ductility residual displacement spectra for bilinear and pinching oscillators with 5%initial damping,directly in terms of easily available seismological,site,and model *** of the available models for the bilinear and pinching oscillators are useful when design spectra for a seismic hazard at a site are not *** statistical estimates of a residual displacement spectrum are proposed in terms of earthquake magnitude,epicentral distance,site geology parameter,and three model parameters for a given set of ductility demand and a hysteretic energy capacity coefficient in the case of bilinear and pinching models,as well as for a given set of pinching parameters for displacement and strength at the breakpoint in the case of pinching model *** proposed scaling model is applicable to horizontal ground motions in the western *** earthquake magnitudes less than 7 or epicentral distances greater than 20 km.

关键词： residual displacement spectrum bilinear hysteresis model pinching hysteresis model nonlinear analysis scaling model

Analysis of the Oscillatory Flows of Multiple Shock Waves in a Constant Area Duct

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Journal of Thermal Science 2024年第3期33卷 794-806页

作者： k JAMES Jintu kIM Heuy Dong Department of Mechanical Engineering Andong National UniversityAndong36729Republic of Korea CAD-IT korea Co. Ltd.Seoul08591Republic of Korea

The oscillatory response of multiple shock waves to downstream perturbations in a supersonic flow is studied numerically in a rectangular *** shock waves are formed inside the duct at a shock Mach number of *** duct has an exit height of H,and the effect of duct resonance on multiple shock oscillations is investigated by attaching exit ducts of lengths 0H,50H,and *** downstream disturbance frequency varied from 10 Hz to 200 Hz to explore the oscillation characteristics of the multiple shock *** oscillatory response of shock waves under self-excited and forced oscillation conditions are analyzed in terms of wall static pressure,shock train leading-edge location,shock train length,and the size of the separation *** extent of the initial shock location increases with an increase in exit duct length for the self-excited oscillation *** analysis of the shock train leading edge and the spectral analysis of wall static pressure variations are *** variation in the shock train length is analyzed using the pressure ratio method for self-excited as well as forced *** RMS amplitude of the normalized shock train length(ζ_(ST))increases with an increase in the exit duct length for the self-excited oscillation *** the downstream perturbation frequency is increased,ζ_(ST)is decreased for exit duct *** all exit duct designs and downstream forcing frequencies,the size of the separation bubble grows and shrinks during the shock oscillations,demonstrating the dependence on duct resonance and forced oscillations.

关键词： shock train downstream disturbance supersonic flow shock wave boundary layer interaction duct resonance flow separation

Impact of Fin Arrangement on Heat Transfer and Melting Characteristics of phase Change Material

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Journal of Thermal Science 2024年第2期33卷 435-456页

作者： Arun UNIYAL Yogesh k.pRAJApATI Department of Mechanical Engineering National Institute of Technology UttarakhandSrinagar(Garhwal)246174India Department of Mechanical Engineering BIT SindriDhanbadJharkhand828123India

present work investigates the heat transfer and melting behaviour of phase change material(pCM) in six enclosures(enclosure-1 to 6) filled with paraffin *** enclosures are equipped with distinct arrangements of the fins while keeping the fin's surface area equal in each *** analysis has been presented to recognize the suitable fin arrangements that facilitate improved heat transfer and melting rate of the *** wall of the enclosure is maintained isothermal for the temperature values 335 k,350 k and 365 *** length of the enclosure including fins is ranging between 0 and *** have been illustrated through the estimation of important performance parameters such as energy absorbing capacity,melting rate,enhancement ratio,and Nusselt *** has been found that melting time(to melt 100% of the pCM) is 60.5%less in enclosure-2(with two fins of equal length) as compared to the enclosure-1,having no *** the fin surface area equal,if the longer fin is placed below the shorter fin(enclosure-3),melting time is further decreased by 14.1% as compared to ***,among all the configurations,enclosure-6 with wire-mesh fin structure exhibits minimum melting time which is 68.4% less as compared to the *** on the findings,it may be concluded that fins are the main driving agent in the enclosure to transfer the heat from heated wall to the *** design and positioning of the fins improve the heat transfer rate followed by melting of the pCM in the entire area of the *** of the favourable vortices and natural convection current in the enclosure accelerate the melting phenomenon and help to reduce charging time.

关键词： phase change material enclosure fin melting fraction energy storage heat transfer

On the functions of astrocyte-mediated neuronal slow inward currents

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Neural Regeneration Research 2024年第12期19卷 2602-2612页

作者： Balázs pál Department of physiology Faculty of MedicineUniversity of DebrecenDebrecenHungary

Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of *** events are significantly slower than the excitatory postsynaptic *** of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto *** are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback *** as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological *** is a growing body of evidence on the roles of slow inward currents on a single neuron or local network *** events often occur in synchro ny on neurons located in the same astrocytic *** synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic *** addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory *** note,there might be important regionspecific differences in the roles and actions triggering slow inward *** greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological *** inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural *** inward currents are significant contributors to paroxysmal depolarizational shifts/interictal *** events are related to epilepsy,but also found in Alzheimer's disease,parkinson's disease,and stroke,leading to the decline of cognitive *** with features overlapping with slow inward currents(excitatory,N-methyl-Dasp

关键词： astrocyte cortical spreading depolarization gliotransmission glutamate neural synchronization NMDA receptor paroxysmal depolarizational shift slow inward current