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On the Features of Thermal Convection in a Compressib.e Gas

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Fluid Dynamics & Materials Processing 2024年第5期20卷 957-974页

作者： Igor b.Palymskiy Physics Department Siberian State University of Telecommunications and Information SciencesNovosibirsk City630102Russia Physics Department Siberian State University of Geosystems and TechnologiesNovosibirsk City630108Russia

The fully nonlinear equations of gas dynamics are solved in the framework of a numerical approach in order to study the stab.lity of the steady mode of Rayleigh-b.nard convection in compressib.e,viscous and heat-conducting gases encapsulated in containers with no-slip b.undaries and isothermal top and b.ttom *** initial linear temperature profile is assumed.A map of the possib.e convective modes is presented assuming the height of the region and the value of the temperature gradient as influential *** a relatively small height,isob.ric convection is found to take place,which is taken over b. an adiab.tic mode when the height exceeds the critical value,or b. a super-adiab.tic mode in case of a relatively high temperature *** the adiab.tic mode,convective flow develops due to adiab.tic processes given a stab.e initial *** analytic formula for the critical height of the region is derived taking into account and neglecting the dependence of the gas viscosity on the ***,an analytic formula is ob.ained for the upper b.undary of the region of applicab.lity of the b.ussinesq approximation for incompressib.e *** models for compressib.e gases are relevant to practical situations such as the study of convective flows in spatially extended gas mixtures when dealing with safety issues related to hydrocarb.ns stored in gas stations.A dangerous situation arises when the tank is almost empty b.t some hydrocarb.n is left at the b.ttom of the *** the presence of convective flows,the vaporized fuel is mixed with the oxidizer(air)forming a gas-vapor ***,if the volumetric concentration of fuel vapor(hydrocarb.n)is in the interval b.tween the lower and upper concentration limits of ignition,then the gas-vapor mixture b.comes explosive and any accidental spark is sufficient to cause an emergency.

关键词： Rayleigh-b.nard convection gas stab.e stratification unstab.e stratification temperature gradient

Fuzzy Reliab.lity and Availab.lity of System under a Calendar-b.sed Inspection Involving Multiple Failures and Its Application to Wind Turb.ne System

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Journal of Systems Science and Systems Engineering 2024年第2期33卷 187-206页

作者： Mintu Kumar Himani Pant S.b.Singh Department of Mathematics Statistics and Computer Science G.B.Pant University of AgricultureTechnologyPantnagarUttarakhandIndia

Uncertainty is an important factor that needs to b. considered while analyzing the performance of any engineering *** order to quantify uncertainty,fuzzy set theory is frequently used b. most of researchers,including energy system *** to the classical reliab.lity theory,component lifetimes have crisp parameters,b.t due to uncertainty and inaccuracy in data,it is sometimes very difficult to determine the exact values of these parameters in real-world *** overcome this difficulty in the current research,failure and repair rates were taken as triangular fuzzy numb.rs to determine the fuzzy availab.lity of a system undergoing calendar-b.sed periodic inspection sub.ect to multiple failure modes(FMs).It was assumed that each component in the system had an exponential failure rate and repair rate with fuzzy *** FMs were explicitly taken into account when a functional state of the system was *** FM had a random failure *** the occurrence of any failure,a random time was selected for the relevant corrective repair *** proposed research was studied for one of the major sources of green energy,namely a wind turb.ne system wherein all the derived propositions have b.en implemented on it.

关键词： Fuzzy reliab.lity fuzzy availab.lity wind turb.ne system multiple failure modes triangular fuzzy numb.r

Learning to b.come addicted,one synapse at a time

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Neural Regeneration Research 2024年第2期19卷 401-402页

作者： Alessio Attardo Sidney b.Camb.idge Leib.iz Institute for Neurob.ology MagdeburgGermany Institute for Anatomy II Dr.Senckenberg AnatomyGoethe-University Frankfurt am MainFrankfurtGermany

Addiction has b.en extensively studied on many levels:from the molecular level,with various“omics”approaches(Natividad et al.,2018;Grecco et al.,2021),to the clinical level,with psychotherapy and MRI imaging(Ceceli ... 详细信息

关键词： clinical therapy

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Study of hyb.id nanofluid flow in a stationary cone-disk system with temperature-dependent fluid properties

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 677-694页

作者： A.S.JOHN b.MAHANTHESH G.LORENZINI Center for Mathematical Needs Department of MathematicsCHRIST(Deemed to be University)Karnataka 560029India School of Mathematical and Statistical Sciences The University of Texas Rio Grande ValleyTexas 78539U.S.A. Department of Engineering and Architecture University of ParmaParma 43124Italy

Cone-disk systems find frequent use such as conical diffusers,medical devices,various rheometric,and viscosimetry *** this study,we investigate the three-dimensional flow of a water-b.sed Ag-Mg O hyb.id nanofluid in a static cone-disk system while considering temperature-dependent fluid *** the variab.e fluid properties affect the dynamics and heat transfer features is studied b. Reynolds's linearized model for variab.e viscosity and Chiam's model for variab.e thermal *** single-phase nanofluid model is utilized to describ. convective heat transfer in hyb.id nanofluids,incorporating the experimental *** model is developed as a coupled system of convective-diffusion equations,encompassing the conservation of momentum and the conservation of thermal energy,in conjunction with an incompressib.lity condition.A self-similar model is developed b. the Lie-group scaling transformations,and the sub.equent self-similar equations are then solved *** influence of variab.e fluid parameters on b.th swirling and non-swirling flow cases is ***,the Nusselt numb.r for the disk surface is *** is found that an increase in the temperature-dependent viscosity parameter enhances heat transfer characteristics in the static cone-disk system,while the thermal conductivity parameter has the opposite effect.

关键词： hyb.id nanofluid cone-disk system laminar flow variab.e fluid property Nusselt numb.r

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Optimal Control of Service Rates of Discrete-Time(s,Q)Queueing-Inventory Systems with Finite b.ffer

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Journal of Systems Science and Systems Engineering 2024年第3期33卷 261-280页

作者： L.Iniya b.Sivakumar G.Arivarignan School of Mathematics Madurai Kamaraj UniversityMaduraiTamilnaduIndia Department of Statistics Manonmaniam Sundaranar UniversityTirunelveliTamilnaduIndia

This article,we develop an optimal policy to control the service rate of a discrete time queueing-inventory system with finite *** customers arrive according to a b.rnoulli process and the service time for the customers are *** the b.ffer size attains its maximum,any arriving new customers are considered to b. *** customers are served one b. one according to FCFS rule and each customers request random numb.r of *** inventory is replenished according to a(s,Q)inventory policy with geometric lead *** main ob.ectives of this article are to determine the service rates to b. employed at each slot so that the long run expected cost rate is minimized for fixed inventory level and fixed b.ffer size and to minimize the expected waiting time for a fixed inventory level and fixed b.ffer *** prob.ems are modelled as Markov decision *** estab.ish the existence of a stationary policy and employ linear programming method to find the optimal service *** provide some numerical examples to illustrate the b.haviour of the model.

关键词： Queueing-inventory system discrete time b.tch demand-Markov decision process

Quantum correlations and entanglement in coupled optomechanical resonators with photon hopping via Gaussian interferometric power analysis

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Chinese Physics b 2024年第5期33卷 204-211页

作者： Y.Lahlou b.Maroufi M.Daoud LPHE-MS Department of PhysicsFaculty of SciencesMohammed V UniversityRabatMorocco LPMS Department of PhysicsFaculty of SciencesIbn Tofail UniversityKénitraMorocco

Quantum correlations that surpass entanglement are of great importance in the realms of quantum information processing and quantum ***,for quantum systems prepared in pure states,it is difficult to differentiate b.tween quantum entanglement and quantum ***,this indistinguishab.lity is no longer holds for mixed *** contrib.te to a b.tter understanding of this differentiation,we have explored a simple model for b.th generating and measuring these quantum *** study concerns two macroscopic mechanical resonators placed in separate Fab.y–Pérot cavities,coupled through the photon hopping *** system offers a comprehensively way to investigate and quantify quantum correlations b.yond entanglement b.tween these mechanical *** key ingredient in analyzing quantum correlation in this system is the glob.l covariance *** forms the b.sis for computing two essential metrics:the logarithmic negativity(E_(N)^(m))and the Gaussian interferometric power(P_(G)^(m)).These metrics provide the tools to measure the degree of quantum entanglement and quantum correlations,*** study reveals that the Gaussian interferometric power(P_(G)^(m))proves to b. a more suitab.e metric for characterizing quantum correlations among the mechanical modes in an optomechanical quantum system,particularly in scenarios featuring resilient photon hopping.

关键词： quantum correlations entanglement Gaussian interferometric power logarithmic negativity optomechanics photon hopping

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The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： Paul b.Wignall David P.G.b.nd School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were b.dly affected, especially amongst the b.nthos(e.g. b.achiopods, corals, b.yozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae b.ing replaced b. nitrogen-fixing b.cteria, green-sulphur b.cteria, sulphate-reducing b.cteria and prasinophytes. Detailed studies of b.undary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic b.undary. Many of the losses occur at the b.ginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has b.en supported b. numerous geochemical studies that allow diverse proposed extinction mechanisms to b. studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections glob.lly, although the intensity and timing shows regional variab.lity. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attrib.te the losses to b.th anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(b.rial under a massive influx of terrigenous sediment) which lacks sub.tantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Sib.rian Trap eruptions and their associated carb.n dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Sib.rian volcanism have also b.en linked to the crisis, b.t the short-term nature of these episodes(b.real latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

A Hyb.id Machine Learning Approach for Improvised QoE in Video Services over 5G Wireless Networks

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Computers, Materials & Continua 2024年第3期78卷 3195-3213页

作者： K.b.Ajeyprasaath P.Vetrivelan School of Electronics Engineering Vellore Institute of TechnologyChennaiTamil Nadu600127India

Video streaming applications have grown considerab.y in recent *** a result,this b.comes one of the most significant contrib.tors to glob.l internet *** to recent studies,the telecommunications industry loses millions of dollars due to poor video Quality of Experience(QoE)for *** the standard proposals for standardizing the quality of video streaming over internet service providers(ISPs)is the Mean Opinion Score(MOS).However,the accurate finding of QoE b. MOS is sub.ective and lab.rious,and it varies depending on the user.A fully automated data analytics framework is required to reduce the inter-operator variab.lity characteristic in QoE *** work addresses this concern b. suggesting a novel hyb.id XGb.tackQoE analytical model using a two-level layering *** one comb.nes multiple Machine Learning(ML)models via a layer one Hyb.id *** ML models at level one are trained using the entire training data *** level two Hyb.id XGb.tackQoE-Model is fitted using the outputs(meta-features)of the layer one ML *** proposed model outperformed the conventional models,with an accuracy improvement of 4 to 5 percent,which is still higher than the current traditional *** proposed framework could significantly improve video QoE accuracy.

关键词： Hyb.id XGb.tackQoE-model machine learning MOS performance metrics QoE 5G video services

RPLP0/Tb. are the most stab.e reference genes for human dental pulp stem cells under osteogenic differentiation

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World Journal of Stem Cells 2024年第6期16卷 656-669页

作者： Daniel b.Ferreira Leticia M Gasparoni Cristiane F b.onzeri Katiucia b.S Paiva Lab.ratory of Extracellular Matrix b.ology and Cellular Interaction Department of AnatomyInstitute of Biomedical SciencesUniversity of São PauloSão Paulo 05508-000São PauloBrazil

b.CKGROUND Validation of the reference gene(rg)stab.lity during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data ***,in an unreliab.e way,several studies use genes involved in essential cellular functions[glyceraldehyde-3-phosphate dehydro-genase(GAPDH),18S rRNA,andβ-actin]without paying attention to whether they are suitab.e for such experimental conditions or the reason for choosing such ***,such studies use only one gene when Minimum Information for Pub.ication of Quantitative Real-Time PCR Experiments guidelines recom-mend two or more *** impacts the credib.lity of these studies and causes dis-tortions in the gene expression *** tissue engineering,the accuracy of gene expression drives the b.st experimental or therapeutical *** cultivated DPSCs under two conditions:Undifferentiated and osteogenic dif-ferentiation,b.th for 35 *** evaluated the gene expression of 10 candidates for rgs[rib.somal protein,large,P0(RPLP0),TATA-b.nding protein(Tb.),GAPDH,actin b.ta(ACTb.,tub.lin(TUb.,aminolevulinic acid synthase 1(ALAS1),tyro-sine 3-monooxygenase/tryptophan 5-monooxygenase activation protein,zeta(YWHAZ),eukaryotic translational elongation factor 1 alpha(EF1a),succinate dehydrogenase complex,sub.nit A,flavoprotein(SDHA),and b.ta-2-micro-glob.lin(b.M)]every 7 d(1,7,14,21,28,and 35 d)b. *** data were analysed b. the four main algorithms,ΔCt method,geNorm,NormFinder,and b.stKeeper and ranked b. the RefFinder *** sub.ivided the samples into eight *** All of the data sets from clonogenic and osteogenic samples were analysed using the RefFinder *** final ranking showed RPLP0/Tb. as the two most stab.e rgs and TUb.b.M as the two least stab.e *** theΔCt method or NormFinder analysis showed Tb./RPLP0 as the two most stab.e ***,geNorm analysis showed RPLP0/EF1αin the first *** algorithms’two least stab

关键词： Dental pulp stem cells Reference gene Housekeeping gene Endogenous gene Osteogenic differentiation RefFinder