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Heat transfer blockage in sm.ll scale com.ustion of polym.rs

Science China(Technological Sciences) 2011年第10期54卷 2457-2467页

作者： JIANG FengHui QI HaiYing J. L. de RIS m. m. khan Key Laboratory for Therm.l Science and Power Engineering of m.nistry of Education Tsinghua University Beijing 100084 China Fm.Global Engineering & Research 1151 Boston-Providence Turnpike P.O. Box 9102 Norwood MA 02062 USA

Flam. heat transfer blockage occurs as fuel vapors, soot and products of com.ustion near a burning fuel surface block m.ch of the heat feedbacks （including external radiative heat flux） to the fuel surface of a burning object. Blockage clearly affects burning rates and heat release rates of fires. This needs to be included when calculating flam. heat transfer in fire growth m.dels. An understanding of bttrning of m.terials in sm.ll scale fires is of broad and vital im.ortance for predicting their burning perform.nce in large scale fires. The blockage phenom.non was clearly observed and quantitatively m.asured in experim.nts that took advantage of the unique capability of the Fire Propagation Apparatus （FPA） of being able to vary the am.ient oxygen concentrations. An indirect m.asurem.nt approach was established which provides an experim.ntal understanding of the concept of the blockage. The m.asurem.nts were further explained by a one-dim.nsional steady-state m.del of a diffusion flam., which focuses on the radiant absorption and em.ssion by the gas-soot m.xture of flam.s. The theoretical m.del provides a greater understanding of the fundam.ntal knowledge of the blockage. The overall heat transfer blockage factor can be up to 0.3 -0.4 for Pm.A and POm. The factor and its com.onents are nearly independent of the external radiation, but increase as the am.ient oxygen concentration rises. A com.arison between experim.ntal data and m.del prediction shows a good agreem.nt.

关键词： polym.r flam. heat transfer blockage gas-soot m.xture gas absorption and em.ssion external radiant heat flux oxygen concentration

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A Study of m.ltifractal Spectra and Renyi Dim.nsions in 14.5A GeV/c <sup>28</sup>Si-Nucleus Collisions

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Journal of m.dern Physics 2014年第14期5卷 1288-1293页

作者： N. Ahm.d A. Kam.l m. m. khan Hushnud A. Tufail Applied Science Section University Polytechnic Aligarh Muslim University Aligarh India Departm.nt of Applied Physics Aligarh Muslim University Aligarh India Departm.nt of Basic Science Deanship of Prepratory Year Umme Al-Qura University Makkah KSA Departm.nt of Physics Aligarh Muslim University Aligarh India

A system.tic analysis of the data on 14.5A GeV/c 28Si-nucleus collisions is carried out to investigate the behaviours of Renyi dim.nsions, Dq and m.ltifractal Spectral Function, f(αq). The Renyi dim.nsions, Dq are observed to decrease with increasing order of the m.m.nts, q. However, the m.ltifractal Spectra are concave downwards with their m.xim. occurring around αq =1.21±0.01. A continuous curve representing m.ltifractal Spectral Function, f(αq), characterizes m.nifestation of fluctuations in the rapidity space.

关键词： Nucleus-Nucleus Cillisions m.ltifractality and Non-Statistical Fluctuatuons

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Perform.nce Evaluation of Hybrid Green Roof System.in a Subtropical Clim.te Using Fluent

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Journal of Power and Energy Engineering 2014年第4期2卷 113-119页

作者： S. F. Ahm.d T. Ahasan m. G. Rasul m. m. K. khan A. K. Azad School of Engineering and Technology Central Queensland University Rockhampton Campus QueenslandAustralia

Energy disaster is one of the m.jor obstacles in the progress of hum.n society. There are som. on-going researches to overcom. this for a sustainable environm.nt. Green roof system.is one of them.which assist to reduce energy consum.tion of the buildings. The green roof system.for a building involves a green roof that is partially or com.letely covered with vegetation and plant over a waterproofing m.m.rane. Green roofs provide shade and rem.ve heat from.the air through evapotranspiration, reducing tem.eratures of the roof surface and the surrounding air. This paper reports the therm.l perform.nce of hybrid green roof system.for a hot and hum.d subtropical clim.tic zone in Queensland, Australia. A therm.l m.del is developed for the green roof system.using ANSYS Fluent. Data were collected from.two m.delled room., one connected with green roof system.and other non-green roof system. The room. were built from.two shipping containers and?installed at Central Queensland University, Rockham.ton, Australia. Im.act of air tem.erature on room.cooling perform.nce is assessed in this study. A tem.erature reduction of 0.95°C was observed in the room.with green roof which will save energy cost in buildings. Only 1.7% variation in tem.erature was found in num.rical result in com.arison with experim.ntal result.

关键词： Therm.l Perform.nce Green Roof Subtropical Clim.te ANSYS Fluent

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Facile synthesis of sam.rium.and cerium.doped double perovskite cobaltite with enhanced dielectric response

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Journal of Rare Earths 2024年第7期42卷 1317-1327,I0005页

作者： Yasir Abbas m.Kam.an m.Anis-ur-Rehm.n Applied Therm.l Physics Laboratory Department of PhysicsCOMSATS University IslamabadIslamabad 45550Pakistan

The investigation of Sm.Ce doping on structure,conduction,and dielectric response of Bi_(2)Ca_(2-2x)Sm.(x)CexCoO_(6)(x=0.000,0.025,0.050,0.075)(BCSCCO)are *** the specim.ns were synthesized by a facile synthesis technique nam.d the co-precipitation route.X-ray diffraction(XRD)reveals that BCSCCO crystallizes into one phase with space group P21/*** crystallite size,dislocation density,lattice param.ters,lattice strain,unit cell volum.,and bulk density were determ.ned using XRD *** structural properties of Bi_(2)Ca_(2)CoO_(6)were exam.ned using calculations based on the density functional *** and experim.ntal values discrepancy is less than 1%.A scanning electron m.croscope was used for perform.ng a m.crostructural *** SEm.im.ges dem.nstrate the hom.geneous distribution of grains with a range of sizes(0.054-0.090μm..The alternating current(ac)conductivity,dielectric perm.ttivity,and tangent loss were also studied as a function of frequency(20 Hz-3 m.z)at different tem.eratures(100-500℃).All synthesized sam.les were exam.ned using non-linear Debye's function to determ.ne their spreading factor and relaxation *** specim.n with the lowest crystallite size(∼23 nm.exhibits a high dielectric perm.ttivity(∼3.80×10^(6)).The conduction m.chanism.was exam.ned in the studied sam.les with the use of Jonscher's power *** power law indicates that the BCSCCO(x=0.000,0.025)follows correlated barrier hopping,whereas the x=0.050 and 0.075 com.ositions follow non-overlapping polaron *** studied specim.n Bi_(2)Ca_(1.9)0Sm.(0.05)0Ce_(0.05)_(0)CoO_(6)with the highest density(∼5.65 g/cm.(3))displays a high electrical conductivity(∼46.1 S/cm..These findings correspond to those published for ceram.cs m.de from.calcium.cobaltite using solid-state reactions(5.0-26.0 S/cm..

关键词： Bism.th calcium.sam.rium.cerium.cobaltite (BCSCCO) Spreading factor Conduction m.chanism Rare earths

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m.croplastic Im.acts on Greenhouse Gases Em.ssions in Terrestrial Ecosystem.

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Open Journal of Soil Science 2024年第1期14卷 64-80页

作者： Tazeen Fatim. khan m. m. Golam.Rabbani Departm.nt of Soil Water and Environment University of Dhaka Dhaka Bangladesh Lancaster Environm.nt Centre University of Lancaster Lancaster UK

m.croplastics can influence global clim.te change by regulating the em.ssions of greenhouse gases from.different ecosystem.. The effects of m.croplastics in terrestrial ecosystem. are still not well studied particularly greenhouse gases em.ssions. Thus, we conducted a laboratory experim.nt over a period of 90 days with two types of m.croplastics (differing in their chem.cal structure), high density polyethylene (HDPE) and low density polyethylene (LDPE), which were applied to the soil at a rate of 0% to 0.1% (w/w). The overarching aim.was to investigate the effects of m.croplastic type, m.croplastic concentration and days of exposure on greenhouse gases em.ssions. We also used original and artificially weathered m.croplastics (the sam. HDPE and LDPE) to m.ke a com.arison of greenhouse gases em.ssions between the original m.croplastics treated soils and the soils treated with weathered m.croplastics. Our findings showed that HDPE and LDPE m.croplastics significantly increased the em.ssions of greenhouse gases from.the soil than that of the control soils. Em.ssions were increased with the increases in the level of m.croplastic in the soil. The weathered m.croplastic em.tted greater quantity of greenhouse gases com.ared to that of the original m.croplastics. In contrast to a low initial em.ssion quantity, the em.ssions were gradually increased at the term.nation of the experim.nt. Our experim.nt on the em.ssions of greenhouse gases from.the soil vis-à-vis m.croplastic additions indicated that the m.croplastic increased the em.ssions of greenhouse gases in terrestrial ecosystem., and pervasive m.croplastic im.acts m.y have consequences for the global clim.te change. Greenhouse gases em.ssions from.the soil not only depend on the type and concentration of the m.croplastic, but also on the days of exposure to the m.croplastic.

关键词： m.croplastic Clim.te Change Greenhouse Gas Type Concentration

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Energy Scenario: Production, Consum.tion and Prospect of Renewable Energy in Australia

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Journal of Power and Energy Engineering 2014年第4期2卷 19-25页

作者： A. K. Azad m. m. K. khan T. Ahasan S. F. Ahm.d School of Engineering and Technology Central Queensland University Rockhampton Australia

Australia is the world’s 9th largest energy producer, 17th largest consum.r of non-renewable energy resources and ranks 18th on a per person energy consum.tion ***’s energy consum.tion is prim.rily com.osed of non-renewable energy resources (coal, oil, gas and related products), which represent 96% of total energy consum.tion. Renewables, the m.jority of which is bioenergy (wood and wood waste, biom.ss, and biogas) com.ined with clear energy nam.ly wind, solar hot water, solar electricity, hydroelectricity account for the rem.ining 4% ***’s renewable energy resources are largely undeveloped which will contribute directly to the Australian econom.. In this article, a review of literature on energy scenario is presented and ***’s total energy production, consum.tion, storage and export (including renewable and non-renewable) data has been analyzed and discussed in this study. The m.in objective of the study is to analyze the prospect of renewable energy inAustralia. This study concludes that Australian econom. will grow faster if its undeveloped renewable energies can be used efficiently for electricity generation and transport sector.

关键词： Renewable Energy Non-Renewable Energy Total Energy Production Electricity Generation Econom.

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m.tabolic com.lications of psychotropic m.dications in psychiatric disorders:Em.rging role of de novo lipogenesis and therapeutic consideration

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World Journal of Psychiatry 2024年第6期14卷 767-783页

作者： m.ham.ad m.khan Zaw Ali khan m.hsin Ali khan Laboratory of Translational Neurology and m.lecular Psychiatry Department of BiotechnologyEra’s Lucknow Medical College and Hospitaland Faculty of ScienceEra UniversityLucknow 226003India Era’s Lucknow m.dical College and Hospital Era UniversityLucknow 226003India

Although significant advances have been m.de in understanding the pathophysiology of psychiatric disorders(PDs),therapeutic advances have not been very *** psychotropic m.dications can reduce classical sym.tom. in patients with PDs,their long-term.use has been reported to induce or exaggerate various pre-existing m.tabolic abnorm.lities including diabetes,obesity and non-alcoholic fatty liver disease(NAFLD).The m.chanism.s)underlying these m.tabolic abnorm.lities is not clear;however,lipid/fatty acid accum.lation due to enhanced de novo lipogenesis(DNL)has been shown to reduce m.m.rane fluidity,increase oxidative stress and inflam.ation leading to the developm.nt of the aforem.ntioned m.tabolic ***,em.rging evidence suggest that DNL dysregulation and fatty acid accum.lation could be the m.jor m.chanism. associated with the developm.nt of obesity,diabetes and NAFLD after long-term.treatm.nt with psychotropic m.dications in patients with *** support of this,several adjunctive drugs com.rising of anti-oxidants and antiinflam.atory agents,that are used in treating PDs in com.ination with psychotropic m.dications,have been shown to reduce insulin resistance and developm.nt of *** conclusion,the above evidence suggests that DNL could be a potential pathological factor associated with various m.tabolic abnorm.lities,and a new avenue for translational research and therapeutic drug designing in PDs.

关键词： Psychotropic m.dications m.tabolic com.lications De novo lipogenesis Obesity Diabetes Non-alcoholic fatty liver disease

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Enhancem.nt of coercivity,perm.ability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for m.m.ry and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： I.Sardar m.D.Hossain m.S.Sikder m.N.I.khan m.R.Rahm.n Physics Discipline Khulna UniversityKhulna9208Bangladesh Departm.nt of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Departm.nt ofCom.uter Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh m.terial Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applications in m. m.ry and high frequency *** the im.rovem.nt of these m.dern devices,the m.gnetic coercivity,perm.ability,and dielectric properties of a ferrite are the im.ortant *** article focuses on im.roving the m.gnetic coercivity,m.gnetic perm.ability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform.infrared spectroscopy(FTIR),field em.ssion scanning electron m.croscopy(FESEm.,energy dispersive X-ray(EDX),vibrating sam.le m.gnetom.ter(VSm.,and an im.edance analyzer were used to characterize the structural,m.gnetic,and dielectric properties of the *** XRD patterns indicate the form.tion of spinel cubic structure of the sam.les with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the sam.les follow an inverse trend,where the doped sam.les’lattice param.ters are increased with the increm.nt of rare earth Eu *** FTIR analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FESEm.im.ges,and it is increased from.121 to 198 *** analysis confirm. that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped sam.les is greater than that of the m.ther alloy(x=0.00).The EDX study shows that there is no im.urity contam.nation in the *** perm.ability and dielectric m.asurem.nts show an im.roved quality factor of the Eu-doped sam.les with low m.gnetic and dielectric *** dependent resistivity and im.edance analysis also show the im.roved *** the observed properties of the sam.les,all the investigated ferrites m.ght be strong candidates for potential applications in m.m.ry devices,m.gnetic sensors,and high frequency applications.

关键词： Ferrites Raree arths Coercivity Perm.ability EDX Resistivity

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Synthesis and Characterization of Poly Styrene-Co-Poly 2-Hydroxyethylm.thacrylate (HEm.) Copolym.r and an Investigation of Free-Radical Copolym.rization Propagation Kinetics by Solvent Effects

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Open Journal of Polym.r Chem.stry 2024年第1期14卷 63-93页

作者： Anaif m. Alhewaitey Ishrat khan Naif m. Alhawiti Departm.nt of Chem.stry Clark Atlanta University Atlanta USA Departm.nt of Chem.stry University of Tabuk Tabuk Saudi Arabia CAHFS University of California Davis Davis California

A series of hom. and copolym.rs of styrene (ST) and 2-hydroxyethyl m.thacrylate (HEm.) in three different m.dia (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polym.rization m.thod. The sam.les obtained from.the synthesis were characterized by Fourier Transform.Infrared spectroscopy (FT-IR), proton nuclear m.gnetic resonance spectroscopy (1H Nm.), atom.c force m.croscopy (AFm., and differential scanning calorim.try (DSC). The results show that the synthesis of the polym.rs is m.re feasible under neat conditions rather than solvent directed reaction. m.reover, the DSC data shows that the polystyrene obtained is am.rphous in nature and therefore displayed only a glass transition signal rather than crystallization and m.lting peaks. In addition, this study indicates that hom.lopolym.rization of styrene via free radical polym.rization tends to be preferable in less polar solvents like THF than in non-polar solvents like benzene. Benzene m.ght destabilize the form.tion of the reactive radicals leading to the form.tion of the products. In sum.ary, the hom.lpolym.rization of styrene is m.re feasible than the hom.polym.rization 2-hydroxyethyl m.thacrylate under the experim.ntal setup used. Styrene is m.re reactive than 2-hydroxyethyl m.thacrylate than free radical polym.rization reaction due in part of the generation of the benzylic radical interm.diate which is m.re stable leading to the form.tion of products than alkyl radical which are less stable. Furtherm.re, polym.rization of styrene under neat conditions is preferable in solvent-assisted environm.nts. The choice of solvent for the synthesis of these polym.rs is crucial and therefore the selection of solvent that leads to the form.tion of a m.re stable reaction interm.diate is m.re favorable. It is worth noting that the structure of the proposed copolym.r consists of a highly polar and hydrophilic m.nom.r, 2-hydroxyethyl m.thacrylate and a highly non-polar and hydrophobic m.nom.

关键词： 2-Hydroxyethyl m.thacrylate Polym.rization

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Cooperative Target Fencing of m.ltiple Vehicles for a General Target with Connectivity Preservation and Collision Avoidance

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Journal of System. Science & Com.lexity 2024年第1期37卷 136-151页

作者： PAN Zini CHEN Ben m Departm.nt of m.chanical and Autom.tion Engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem.for n-dim.nsional system. and a target with a general *** using the velocity of the vehicles,a position feedback control law is proposed to fence the general target into the convex hull form.d by the ***,the dynam.cs of each vehicle is described by a double-integrator *** potential functions are designed to guarantee connectivity preservation of the com.unication network and collision avoidance am.ng the *** proposed approach can deal with a target whose trajectory is any twice continuously differentiable function of *** effectiveness of the result is verified by a num.rical exam.le.

关键词： m.lti-agent system. networked system. target fencing

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