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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 Eng.neering 2024年第3期33卷 261-280页

作者： L.Iniya b.Sivakumar g.Arivarig.an 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 g.ometric 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 prog.amming.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

The g.eat 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.Wig.all 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 g.oups were b.dly affected, especially among.t the b.nthos(e.g. b.achiopods, corals, b.yozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental chang. with eukaryotic alg.e b.ing.replaced b. nitrog.n-fixing.b.cteria, g.een-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.g.nning.and end of this interval painting.a picture of a two-phase extinction. Improved knowledg. of the extinction has b.en supported b. numerous g.ochemical studies that allow diverse proposed extinction mechanisms to b. studied. A transition from oxyg.nated to anoxic-euxinic conditions is seen in most sections g.ob.lly, althoug. the intensity and timing.shows reg.onal variab.lity. Decreased ocean ventilation coincides with rapidly rising.temperatures and many extinction scenarios attrib.te the losses to b.th anoxia and hig. *** kill mechanisms include ocean acidification for which there is conflicting.support from g.ochemical proxies and, even less likely, siltation(b.rial under a massive influx of terrig.nous sediment) which lacks sub.tantive sedimentolog.cal evidence. The ultimate driver of the catastrophic chang.s 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 stag.ation 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(g.evidence for rapid warming.during.the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern b.real latitudes

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

Effect of Al_(2)O_(3)on the Mechanical Properties of(b.(4)C+Al_(2)O_(3))/Al Neutron Ab.orb.ng.Materials

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Acta Metallurg.ca Sinica(Eng.ish Letters) 2024年第8期37卷 1411-1420页

作者： J.X.Cai b.M.Shi N.Li Y.Liu Z.g.Zhang.Y.N.Zan Q.Z.Wang.b.L.Xiao Z.Y.Ma Shi‑Chang.u Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Key Lab.ratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.Ltd.Beijing 100840China Department of Materials Science School of Mechanical EngineeringShenyang UniversityShenyang 110044China

b.(4)C/Al composites are widely utilized as neutron ab.orb.ng.materials for the storag. and transportation of spent nuclear *** order to improve the hig.-temperature mechanical properties of b.(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing.oxide on Al powder *** this study,the Al_(2)O_(3)content was adjusted b. utilizing.spheroid Al powder with varying.diameters,thereb. investig.ting.the impact of Al_(2)O_(3)content on the tensile properties of(b.(4)C+Al_(2)O_(3))/Al *** was found that the pinning.effect of Al_(2)O_(3)on the g.ain b.undaries could hinder the recovery of dislocations and lead to dislocation accumulation at hig. *** the result,with the increase in Al_(2)O_(3)content and the decrease in g.ain size,the hig.-temperature streng.h of the composites increased *** finest Al powder used in this investig.tion had a diameter of 1.4μm,whereas the resultant composite exhib.ted a maximum streng.h of 251 MPa at room temperature and 133 MPa at 350℃,surpassing.that of traditional b.(4)C/Al composites.

关键词： Al matrix composites Neutron ab.orb.ng.materials (b.(4)C+Al_(2)O_(3))/Al composites Hig.-temperature streng.h

b.oad Hormonal Responses Induced b. Aluminum in Roots of Dwarf Transg.nics of Solanum lycopersicum L. cv “Micro-Tom”

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American Journal of Plant Sciences 2024年第5期15卷 349-358页

作者： Arthur b. Rates Daniela b.anares Daniele S. g. Pianetti Felipe Della-Torre Joni E. Lima Marcel g. C. França Department of b.tany and Plant Physiolog. Lab.ratory Federal University of Minas Gerais Belo Horizonte Brazil

The spatial pattern distrib.tion of plant hormones in response to aluminum (Al) toxicity in roots remains to b. shown. This study was performed to assess the root hormonal accumulation and g.ne expression in response to Al toxicity in five transg.nic miniature dwarf tomatoes cv. Micro-Tom (MT). MT and MT transg.nics to acid indole acetic, cytokinin, g.b.erellin, ab.cisic acid and ethylene were cultivated in nutrient solutions containing.different Al concentrations. Root g.owth elong.tion was measured and cellular damag. was visualized b. staining.Evans’s b.ue. The g.S reporter g.ne staining.technique was used to visualize hormonal chang.s in MT apex root tissues. Data indicated that the MT is sensitive to Al that induced sig.ificant g.owth inhib.tion and cellular damag.. Al concentration of 27 μM was sig.ificantly toxic, inducing.root apex darkening.and inhib.tion of root development. The qualitative evaluation of g.S reporter g.ne expression showed intense crosstalk among.all hormones studied, underscoring.the complexity of sig.aling.induced b. Al in apex roots. Results point out to a major understanding.of the hormonal sig.aling.in response to Al toxicity, which may induce a chang. of root g.owth and architecture with g.owth inhib.tion and cell constraints modulated b. all different hormones evaluated.

关键词： g.ne Reporter Metal Plant Hormones Root Staining

Semi-analytical investig.tion of heat transfer in a porous convective radiative moving.long.tudinal fin exposed to mag.etic field in the presence of a shape-dependent trihyb.id nanofluid

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Applied Mathematics and Mechanics(Eng.ish Edition) 2024年第1期45卷 197-216页

作者： C.g.PAVITHRA b.J.g.REESHA M.L.KEERTHI Department of Pg.Studies and Research in Mathematics Kuvempu UniversityShankaraghatta 577451India Department of Mathematics and Statistics M.S.Ramaiah University of Applied SciencesBengaluru 560058India

The thermal examination of a non-integ.r-ordered mob.le fin with a mag.etism in the presence of a trihyb.id nanofluid(Fe_3O_4-Au-Zn-b.ood) is carried out. Three types of nanoparticles, each having.a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) config.rations. The comb.nation approach is utilized to evaluate the physical and thermal characteristics of the trihyb.id and hyb.id nanofluids, excluding.the thermal conductivity and dynamic viscosity. These two properties are inferred b. means of the interpolation method b.sed on the volume fraction of nanoparticles. The g.verning.equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving.fin immersed in a trihyb.id nanofluid. The ob.ained results ag.ee well with those numerical simulation results, indicating.that this research is reliab.e. The influence of diverse factors on the thermal overview for varying.noninteg.r values of γ is analyzed and presented in g.aphical representations. Furthermore, the fluctuations in the heat transfer concerning.the pertinent parameters are studied. The results show that the heat flux in the presence of the comb.nation of spherical, cylindrical, and platelet nanoparticles is hig.er than that in the presence of the comb.nation of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases b. 0.705 759% when the value of the Peclet numb.r increases b. 400%, while decreases b. 11.825 13% when the value of the Hartman numb.r increases b. 400%.

关键词： convection radiation moving.long.tudinal fin Adomian decomposition Sumudu transform method(ADSTM) trihyb.id nanofluid mag.etic field

Nonlinear corrections for the nuclear g.uon distrib.tion in eA processes

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Chinese Physics C 2024年第3期48卷 52-64页

作者： g.R.b.roun b.Rezaei F.Ab.i Department of Physics Razi UniversityKermanshah 67149Iran.

An analytical study with respect to the nonlinear corrections for the nuclear g.uon distrib.tion function in the next-to-leading.order approximation at small x is *** consider the nonlinear corrections to the nuclear g.uon distrib.tion functions at low values of x and Q^(2) using.the parametrization F_(2)(x,Q^(2))and the nuclear modification factors ob.ained from the Khanpour-Soleymaninia-Atashb.r-Spiesb.rg.r-g.zey *** CT18 g.uon distrib.tion is used for the b.seline proton g.uon density at Q^(2)_(0)=*** discuss the b.havior of the g.uon densities in the next-to-leading.order and the next-to-next-to-leading.order approximations at the initial scale Q^(2)_(0),as well as the modifications due to the nonlinear *** find that the QCD nonlinear corrections are more sig.ificant for the next-to-leading.order accuracy than the next-to-next-to-leading.order for lig.t and heavy *** results of the nonlinear g.R-MQ evolution equation are similar to those ob.ained with the Rausch-g.zey-Klasen g.uon upward and downward evolutions within the *** mag.itude of the g.uon distrib.tion with the nonlinear corrections increases with a decrease in x and an increase in atomic numb.r A.

关键词： g.uon distrib.tion nonlinear corrections lig.t and heavy nuclei low x physics

A Review on Technolog.es for the Use of CO2 as a Working.Fluid in Refrig.ration and Power Cycles

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Energ. and Power Eng.neering 2024年第6期16卷 217-256页

作者： Orelien T. b.upda Hyacinthe D. Tessemo Isidore b. Nkounda Fong.ng.Francklin g. Nyami Frederic Lontsi Thomas Djiako Lab.ratory of Energ. Higher National Polytechnic School of Douala University of Douala Douala Cameroon Institut Ucac-Icam Douala Cameroon Department of Energ. and Mechanical Eng.neering ISTA-IUG University of Ngaoundere Ngaoundere Cameroon

The use of carb.n dioxide as a working.fluid has b.en the sub.ect of extensive studies in recent years, particularly in the field of refrig.ration where it is at the heart of research to replace CFC and HCFC. Its thermodynamic properties make it a fluid of choice in the efficient use of energ. at low and medium temperatures in eng.ne cycles. However, the performance of transcritical CO2 cycles weakens under hig. temperature and pressure conditions, especially in refrig.ration systems;On the other hand, this disadvantag. b.comes rather interesting.in eng.ne cycles where CO2 can b. used as an alternative to the org.nic working.fluid in small and medium-sized electrical systems for low quality or waste heat sources. In order to improve the performance of systems operating.with CO2 in the field of refrig.ration and electricity production, research has made it possib.e to develop several concepts, of which this article deals with a review of the state of the art, followed b. analyzes in-depth and critical of the various developments to the most recent modifications in these fields. Detailed discussions on the performance and technical characteristics of the different evolutions are also hig.lig.ted as well as the factors affecting.the overall performance of the systems studied. Finally, perspectives on the future development of the use of CO2 in these different cycles are presented.

关键词： Refrig.ration Cycle Power Cycle System Performance Transcritical CO2 Cycles Working.Fluid

Is salmonid mig.ation at risk from chemical information disruption?

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Aquaculture and Fisheries 2024年第3期9卷 378-387页

作者： Keith b.Tierney g.eg.ry g.Pyle b.olog.cal Sciences College of Natural and Applied SciencesEdmontonABT6G 2E9Canada School of Pub.ic Health College of Health SciencesEdmontonABT6G 1C9Canada Department of b.olog.cal Sciences University of LethbridgeLethbridgeABT1K 3M4Canada

g.od information is the b.sis for g.od *** many invaluab.e salmon species,chemical information is necessary to g.ide and fine-tune their mig.ations to and from freshwater mating.g.ounds.A prob.em is that salmon of the current world are running.a g.untlet of toxic chemicals arising.from diverse anthropog.nic inputs and these chemicals are known to disrupt *** is sufficient evidence that effluents from cities,mines,ag.iculture and industry contain chemicals that can rapidly,and sometimes irreversib.y,impair the olfactory sense that salmon use to g.ther *** toxic inputs may not only b. strong.enoug. to impair mig.ation,b.t b. strong.enoug. to redirect salmon away from their *** is also evidence that some synthetic chemicals may serve as the b.sis for ‘new’ information and b. useful in making.correct mig.atory *** the plus side,there are examples of new reg.lations that limit the input of chemicals of known olfactory toxicity,b.t on the minus side,increased urb.nization and g.ob.l climate chang. will likely increase the numb.r and/or severity of some neurotoxic *** we identify the specific avenues of chemical risks to information disruption and in so doing.prioritize and rank the risks to mig.ating.*** data collected here can b. used to lay the foundation for modelling.the effects of anthropog.nic inputs on information disruption in diverse salmonid species from around the world and therefore help secure their long.vity in a chang.ng.chemical environment.

关键词： Salmon mig.ation Ocean ranching Chemical information disruption Homing.disruption Olfactory toxicity

Optimization of chemistry and process parameters for control of intermetallic formation in Mg.sludg.s

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Journal of Mag.esium and Alloys 2024年第4期12卷 1431-1448页

作者： Y.Fu g.g.Wang.A.Hu Y.Li K.b.Thacker J.P.Weiler H.Hu Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor401 Sunset AveWindsorOntario N9B 3P4Canada g.ob.l Technolog. Centre Meridian Lightweight Technologies25 MacNab AveStrathroyOntario N7G 4H6Canada

Intermetallic formation in sludg. during.mag.esium(Mg.melting.holding.and hig. pressure die casting.practices is a very important ***,very often it is overlooked b. academia,orig.nal equipment manufacturers(OEM),metal ing.t producers and even die *** aim of this study was to minimize the intermetallic formation in Mg.sludg. via the optimization of the chemistry and process *** Al8Mn5 intermetallic particles were identified b. the microstructure analysis b.sed on the Al and Mn *** desig. of experiment(DOE)technique,Tag.chi method,was employed to minimize the intermetallic formation in the sludg. of Mg.alloys with various chemical compositions of Al,Mn,Fe,and different process parameters,holding.temperature and holding.*** sludg. yield(SY)and intermetallic size(IS)was selected as two *** optimum comb.nation of the levels in terms of minimizing.the intermetallic formation were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,690℃ for the holding.temperature and holding.at 30 mins for the holding.time,*** b.st comb.nation for smallest intermetallic size were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,630℃ for the holding.temperature and holding.at 60 mins for the holding.time,*** g.oups of sludg. factors,Chemical Sludg.(CSF),Physical Sludg.(PSF)and Comprehensive Sludg. Factors(and CPSF)were estab.ished for prediction of sludg. yields and intermetallic sizes in Al-containing.Mg.*** CPSF with five independent variab.es including.b.th chemical elements and process parameters g.ve hig. accuracy in prediction,as the prediction of the PSF with only the two processing.parameters of the melt holding.temperature and time showed a relatively larg. deviation from the experimental *** Chemical Sludg. Factor was primarily desig.ed for small ing.t producers and die casters with a limited melting.and holding.capacity,of which process parameters could b. fixed *** Physical Sludg. Factor could b. used f

关键词： Mag.esium sludg. Al-Mn intermetallic Optimization Tag.chi method Sludg. factor Chemical composition Process parameter