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Cryogenic and conventional milling of AZ91 magnesium alloy

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

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Background removal from global auroral images:Data-driven dayglow modeling

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Earth and planetary physics 2024年第1期8卷 247-257页

作者： A.Ohma M.Madelaire k.M.Laundal J.p.Reistad S.M.Hatch S.Gasparini S.J.Walker Birkeland Centre for Space Science Department of Physics and TechnologyUniversity of BergenBergenNorway

Global images of auroras obtained by cameras on spacecraft are a key tool for studying the near-Earth ***,the cameras are sensitive not only to auroral emissions produced by precipitating particles,but also to dayglow emissions produced by photoelectrons induced by *** emissions and scattered sunlight can contribute to the background *** fully utilize such images in space science,background contamination must be removed to isolate the auroral *** we outline a data-driven approach to modeling the background intensity in multiple images by formulating linear inverse problems based on B-splines and spherical *** approach is robust,flexible,and iteratively deselects outliers,such as auroral *** final model is smooth across the terminator and accounts for slow temporal variations and large-scale asymmetries in the *** demonstrate the model by using the three far ultraviolet cameras on the Imager for Magnetopause-to-Aurora Global Exploration(IMAGE)*** method can be applied to historical missions and is relevant for upcoming missions,such as the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.

关键词： aurora dayglow modeling global auroral images far ultraviolet images dayglow removal

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Effects of the level and source of dietary physically effective fiber on feed intake, nutrient utilization, heat energy, ruminal fermentation,and milk production by Alpine goats

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Animal Nutrition 2024年第2期17卷 312-324页

作者： Raquel V.Lourencon Amlan k.patra Luana p.S.Ribeiro Ryszard puchala Wei Wang Terry A.Gipson Arthur L.Goetsch American Institute for Goat Research Langston University

Thirty-two primiparous and 31 multiparous Alpine goats were used to determine influences of diets varying in level and source of forage on performance in early to mid-lactation for 16 wk. Diets consisted of 40%, 50%, 60%, and 70% forage(designated as 40F, 50F, 60F, and 70F, respectively) with 60F and 70F containing coarsely ground grass hay(primarily orchardgrass) and 40F and 50F containing cottonseed hulls, alfalfa pellets, and coarsely ground wheat hay. Diets contained 15.9% to 16.3% crude protein and37.8%, 42.1%, 53.5%, and 55.4% neutral detergent fiber(NDF) with 10.0%, 15.8%, 50.1%, and 55.5% particle retention on a 19-mm sieve, and 26.1%, 29.6%, 38.3%, and 40.0% physically effective NDF(pe NDF) for 40F,50F, 60F, and 70F, respectively. Dry matter intake(2.71, 2.75, 1.96, and 1.95 kg/d) and milk yield(2.82,2.71, 2.23, and 2.10 kg/d for 40F, 50F, 60F, and 70F, respectively) were lower(p p > 0.05), but digestibility of NDF was greater(p pectively). Diet affected(p k fat(3.16%, 3.37%, 2.93%, and 2.97%) and protein concentrations(2.62%, 2.69%, 2.58%, and 2.52% for 40F, 50F, 60F, and 70F, respectively). Milk energy yield was greater(p ke was not affected(p > 0.05) by diet and was lower(p primiparous vs. multiparous goats(2.71 and 3.09 MJ/kg). Ruminal p H and acetate proportion were greater for 60F and 70F than for the other diets and the proportion of butyrate was lower for the two diets highest in fiber. The mean lengths of time spent ruminating, eating, standing, and lying were not affected(p > 0.05) by diet or parity, but many interactions involving diet, period, hour, and parity were significant(p performance o

关键词： physically effective fiber Alpine goat Lactation Ruminal fermentation Feeding behavior

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Unmixing detrital zircon U-pb ages reveals tectonic and climatic depositional influences on the Carboniferous Ansilta Formation,Calingasta-Uspallata Basin,Western Argentina

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Geoscience Frontiers 2024年第4期15卷 61-77页

作者： J.R.Malone J.E.Malone J.L.Isbell D.H.Malone J.p.Craddock k.N.pauls Department of Geological Sciences Jackson School of GeosciencesUniversity of Texas at AustinAustinTX 78712USA Iowa Geological Survey University of IowaIowa CityIA 52240USA Department of Geosciences University of Wisconsin-MilwaukeeMilwaukeeWI 53211USA Department of Geography Geology and the EnvironmentIllinois State UniversityNormalIL 61790-4400USA

The Late paleozoic Ice Age(LpIA)was a principal control of sedimentation across Gondwana from the late Devonian through early *** assess the hypothesis that glacial to interglacial transitions in western Argentina were the primary control influencing sediment routing patterns among the various Carboniferous-permian basins in western *** Carboniferous Ansilta Formation consists of glaciomarine,nearshore,and fluvial systems deposited during the LpIA along the eastern margin of the Calingasta-Uspallata Basin in *** lower,glacially influenced succession of the Ansilta Formation records at least five glacial advances;the upper succession of consists of progradational shallow marine,deltaic,and fluvial *** combine 1225 new U-pb zircon ages from six samples of the Carboniferous Ansilta Formation in the Calingasta-Uspallata Basin with 5864 U-pb ages from 147 pub-lished samples in the detrital pymix forward mixture model to characterize provenance *** the glacially influenced lower Ansilta Formation,sediment was derived locally from the protoprecordillera,which was a prominent highland with alpine glaciers flowing west and east into the Calingasta-Uspallata and paganzo basins,***,there was little or no connection between these two basins during Serpukhovian-Bashkirian *** fluvial/deltaic upper Ansilta had distal sediment sources in the Sierras ***,our results support the collapse of the protoprecordillera topographic barrier,enabling drainage patterns connecting the paganzo and Calingasta-Uspallata basins by late pennsylvanian-early permian time.

关键词： Late paleozoic Ice Age Argentina Calingasta-Uspallata Basin Ansilta Formation Detrital zircon provenance

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Chronic disease patients have fewer social contacts:A pilot survey with implications for transmission dynamics

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Infectious Disease Modelling 2024年第3期9卷 926-930页

作者： J.Vanderlocht S.Møgelmose k.Van kerckhove p.Beutels N.Hens Interuniversity Institute of Biostatistics and Statistical Bioinformatics Data Science InstituteHasselt UniversityHasseltBelgium Centre for Health Economic Research and Modelling Infectious Diseases University of AntwerpAntwerpBelgium

Non-communicable diseases(NCD)are the most important cause of death in the *** socio-economic costs associated with NCDs makes it imperative to prevent and control them in the 21st *** severe toll that the COVID-19 pandemic has taken worldwide is an unfortunate illustration of our limited insight into the infectious risk for the global ***-incidence between NCD and infection offers an underexplored opportunity to design preventive *** a pilot survey,we observed that the NCD population displays a substantial reduction in their social contacting behavior as compared to the general *** indicates that existing mathematical models based on contact surveys in the general population are not applicable to the NCD population and that the risk of acquiring an infection following a contact is probably *** demonstration of reduced social mixing in several chronic conditions,raises the question to what extent the social mixing is influenced by the burden of *** advocate the design of disease-specific contact surveys to address how the burden of disease associates with social contact behavior and the risk of *** SARS-CoV-2 pandemic offers an unprecedented opportunity to gain insight into the importance of infection in the NCD population and to find ways to improve healthcare procedures.

关键词： survey mixing insight

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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

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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

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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

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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

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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

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