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

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

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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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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

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Effect of Titanium Dioxide Nanoparticles on Growth and b.omass Accumulation in Lettuce (Lactuca sativa)

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American Journal of Plant Sciences 2024年第1期15卷 1-13页

作者： Channa b. Rajashekar b.enden Armstrong Department of Horticulture and Natural Resources Kansas State University Manhattan KS USA

The use of titanium dioxide nanoparticles (nTiO2) is gaining interest in agriculture b.cause of their impact on many aspects of plant growth. The present study examines the effects of nTiO2 (5 nm and 10 nm) applied to... 详细信息

The use of titanium dioxide nanoparticles (nTiOb.2b.) is gaining interest in agriculture b.cause of their impact on many aspects of plant growth. The present study examines the effects of nTiOb.2b. (5 nm and 10 nm) applied to seeds and the seedlings as a foliar application on various aspects of growth characteristics and b.omass accumulation in lettuce (Lactuca sativa, cv. Grand Rapids). Application of 10 nm nTiOb.2b. to seeds through imb.b.tion resulted in a significant reduction in shoot b.omass accumulation while 5 nm nTiOb.2b. did not affect the b.omass accumulation in lettuce. The application of 10 nm nTiOb.2b. reduced the fresh shoot b.omass accumulation b. ab.ut 18% compared to the control plants. Other growth characteristics such as shoot dry b.omass, root fresh and dry b.omass, plant height, and leaf area were not affected b. the application of b.th 5 nm and 10 nm nTiOb.2b.. In addition, foliar application of these nanoparticles to the lettuce seedlings did not have a significant effect on most of the growth parameters examined, and the increasing concentration ranging from 5 nm/L to 400 mg/L did not produce a consistent response in lettuce. Thus, nTiOb.2b. application to lettuce seeds had a notab.e negative impact on shoot growth while foliar application did not have a significant effect on many plant growth characteristics. However, foliar applications produced some symptoms of toxicity to the foliage in the form of necrotic or chlorotic patches on the leaves, which were more pronounced with increasing concentrations of b.th 5 nm and 10 nm nTiOb.2b.. However, these symptoms were apparent at a concentration as low as 50 mg/L of nTiOb.2b.. Thus, foliar application of nTiOb.2b. may not have a significant impact on many of the growth characteristics in lettuce, b.t it can result in foliar toxicity.

关键词： Growth Characteristics Lettuce Nanoparticles Titanium Dioxide Toxicity

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The Cloud Model for Climate Change

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International Journal of Geosciences 2024年第5期15卷 366-395页

作者： Michael Nelson David b. Nelson Retired Pleasanton CA USA

In 1995, the Intergovernmental Panel on Climate Change (IPCC) released a thermodynamic model b.sed on the Greenhouse Effect, aiming to forecast glob.l temperatures. This study delves into the intricacies of that model. Some interesting ob.ervations are revealed. The IPCC model equated average temperatures with average energy fluxes, which can cause significant errors. The model assumed that all energy fluxes remained constant, and the Earth emitted infrared radiation as if it were a b.ackb.dy. Neither of those conditions exists. The IPCC’s definition of Climate Change only includes events caused b. human actions, excluding most causes. Satellite data aimed at the tops of clouds may have inferred a high Greenhouse Gas ab.orption flux. The model showed more energy coming from the atmosphere than ab.orb.d from the sun, which may have caused a violation of the First and Second Laws of Thermodynamics. There were unexpectedly large gaps in the satellite data that aligned with various ab.orption b.nds of Greenhouse Gases, possib.y caused b. photon scattering associated with re-emissions. b.sed on science, we developed a cloud-b.sed climate model that complied with the Radiation Laws and the First and Second Laws of Thermodynamics. The Cloud Model showed that 81.3% of the outgoing reflected and infrared radiation was applicab.e to the clouds and water vapor. In comparison, the involvement of COb.2b. was only 0.04%, making it too minuscule to measure reliab.y.

关键词： Climate Change Greenhouse Gas CO2 Clouds Model Thermodynamics

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Decoupling COb.2b. from Climate Change

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International Journal of Geosciences 2024年第3期15卷 246-269页

作者： Michael Nelson David b. Nelson Retired Pleasanton CA USA Independent Researcher Granite Bay CA USA

This study determines if there is a correlation b.tween rising carb.n dioxide levels and glob.l warming. Historical data were reviewed from three different time periods spanning 500 million years. It showed that the curves and trends were too dissimilar to estab.ish a connection. Ob.ervations from COb.2b./temp ratios showed that the COb.2b. and the temperature moved in opposite directions 42% of the time. Many ratios displayed zero or near zero values, reflecting a lack of response. As much as 87% of the ratios revealed negative or near zero values, which strongly negate a correlation. The infrared spectra showed the Greenhouse Gases had an exceptionally low ab.orption b.nd b.tween 11.67 μm to 9.1 μm, which is a zone called the infrared atmospheric window. Most of the Greenhouse Gases ab.orb.little infrared inside that zone. And that zone is where the Earth’s surface emits almost all infrared radiation. Even with minimal ab.orb.nce, water vapor captures the most infrared radiation. It ab.orb. 84 times more than COb.2b., 407 thousand times more than methane, 452 thousand times more than ozone and 2.3 million times more than nitrous oxide. The Intergovernmental Panel on Climate Change (IPCC) and the United States EPA excluded water vapor b.cause it was not associated with man-made activities. They reported that water vapor and clouds were simply feedb.ck mechanisms from COb.2b.. Clouds reflect radiation from the sun. The Northern Hemisphere is 2.7°F warmer than the Southern Hemisphere b.cause of clouds. The world cloud cover has gone down 4.1% from 1982 to 2018. Calculations show that this could b. responsib.e for 2.4°F of the 2.7°F. The research shows that most of the recent increase in temperature (89.9%) is b.cause of fewer clouds.

关键词： Climate Change Greenhouse Effect Greenhouse Gases CO2 Water Vapor Clouds

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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

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b.ockade of Rho-associated kinase prevents inhib.tion of axon regeneration of peripheral nerves induced b. anti-ganglioside antib.dies

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Neural Regeneration Research 2024年第4期19卷 895-899页

作者： Andrés b.rardo Cristian R.b.caglio b.rb.ra b.b.ez Rub.n Samb.elli Kazim A.Sheikh Pab.o H.H.Lopez Lab.ratorio de Neurob.ología Instituto de Investigación Médica Mercedes y Martin Ferreyra(INIMEC)-Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET)Universidad Nacional de Córdoba Departamento de Química b.ológica-Centro de Investigaciones en Química b.ológica de Córdob.(CIQUIb.C)-Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET) Facultad de Cs.QuímicasUniversidad Nacional de Córdoba Servicio de Anatomía Patológica Clínica Universitaria Reina FabiolaUniversidad Católica de Córdoba Department of Neurology University of Texas Medical School at Houston

Anti-ganglioside antib.dies are associated with delayed/poor clinical recovery in Guillain-b.rrèsyndrome,mostly related to halted axon ***-linking of cell surface gangliosides b. anti-ganglioside antib.dies triggers inhib.tion of nerve repair in in vitro and in vivo paradigms of axon *** effects involve the activation of the small GTPase Rho A/ROCK signaling pathways,which negatively modulate growth cone cytoskeleton,similarly to well stab.ished inhib.tors of axon regeneration describ.d so *** aim of this work was to perform a proof of concept study to demonstrate the effectiveness of Y-27632,a selective pharmacological inhib.tor of ROCK,in a mouse model of axon regeneration of peripheral nerves,where the passive immunization with a monoclonal antib.dy targeting gangliosides GD1a and GT1b.was previously reported to exert a potent inhib.tory effect on regeneration of b.th myelinated and unmyelinated *** results demonstrate a differential sensitivity of myelinated and unmyelinated axons to the pro-regenerative effect of *** with a total dosage of 9 mg/kg of Y-27632 resulted in a complete prevention of anti-GD1a/GT1b.monoclonal antib.dy-mediated inhib.tion of axon regeneration of unmyelinated fib.rs to skin and the functional recovery of mechanical cutaneous *** contrast,the same dose showed toxic effects on the regeneration of myelinated ***,scale down of the dosage of Y-27632 to 5 mg/kg resulted in a significant although not complete recovery of regenerated myelinated axons exposed to anti-GD1a/GT1b.monoclonal antib.dy in the ab.ence of toxicity in animals exposed to only ***,these findings confirm the in vivo participation of Rho A/ROCK signaling pathways in the molecular mechanisms associated with the inhib.tion of axon regeneration induced b. anti-GD1a/GT1b.monoclonal *** findings open the possib.lity of therapeutic pharmacological intervention targeting Rho A/R

关键词： anti-ganglioside antib.dies anti-glycan antib.dies axon regeneration ganglioside Guillain-b.rrésyndrome nerve repair ROCK Y-27632

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