检索结果-南通市图书馆

Numerical Study of Flow and Gas Diffusion in the Near-Wake behind an Isolated Building

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2009年第6期26卷 1241-1252页

作者： Mohamed F.yassin Department of Environmental Technology Management College for WomenKuwait University P.O.Box 5969KuwaitSafat 13060Kuwait Faculty of Engineering Assiut UniversityAssiut-71516Egypt

To assist validation of the experimental data of urban pollution dispersion, the effect of an isolated building on the flow and gaseous diffusion in the wake region have been investigated numerically in the neutrally stratified rough-walled turbulent boundary layer. Numerical studies were carried out using Computational Fluid Dynamics （CFD） models. The CFD models used for the simulation were based on the steady-state Reynolds-Average Navier-Stoke equations （RANS） with κ-ε turbulence models; standard κ-ε and RNG κ-ε models. Inlet conditions and boundary conditions were specified numerically to the best information available for each fluid modeling simulation. A gas pollutant was emitted from a point source within the recirculation cavity behind the building model. The accuracy of these simulations was examined by comparing the predicted results with wind tunnel experimental data. It was confirmed that simulation using the model accurately reproduces the velocity and concentration diffusion fields with a fine-mish resolution in the near wake region. Results indicated that there is a good agreement between the numerical simulation and the wind tunnel experiment for both wind flow and concentration diffusion. The results of this work can help to improve the understanding of mechanisms of and simulation of pollutant transport in an urban environment.

关键词： atmospheric turbulence CFD model isolated building pollutant dispersion

Optimizing Cr^(3+) concentration and evaluating energy transfer from Cr^(3+) to Nd^(3+) in Cr,Nd:GGG nanocrystals prepared by sol-gel method

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2016年第11期34卷 1077-1082页

作者： yassin Alshikh Mohamad Yomen Atassi Zafer Moussa Department of Applied Physics Higher Institute for Applied Science and Technology

Nanopowder of Cr：GGG and nanopowder of Cr,Nd：GGG with different concentrations of Cr3＋ ranging from 0.1 at.% to 1.5 at.% were synthesized by the sol-gel method using acetic acid and ethylene glycol. Thermal gravimetric analysis and differential scanning calorimetry （TGA-DSC）, X-ray diffraction （XRD） and photoluminescence spectroscopy were used to characterize the powder. The crystallite size was about 58 nm when treated at 1000 oC for 2 h. Cr3＋ photoluminescence spectrum in GGG showed a broad band emission around 730 nm. The intensity of this band decreased when co-doped with Nd, indicating an efficient energy transfer from Cr3＋ to Nd3＋. Photoluminescence intensity of Nd in Cr,Nd：GGG at 1.06μm showed that the optimum concentration of Cr3＋ was about 1 at.% （more or less） for 1 at.% Nd3＋. This result was also confirmed by chromium fluorescence decay rate analysis. Energy transfer efficiency was found to be about 84% for 1 at.% concentration of each chromium and neodymium.

关键词： nanopowder Cr,Nd:GGG sol-gel fluorescence lifetime energy transfer efficiency rare earths

Experimental study and Shannon entropy analysis of pressure fluctuations and flow mode transition in fluidized dense phase pneumatic conveying of fly ash

在线全文

学校读者我要写书评

暂无评论

Particuology 2020年第2期18卷 169-178页

作者： yassin Alkassar Vijay KAgarwal RKPandey Niranjana Behera Industrial Tribology Machine Dynamic and Maintenance Engineering CentreIndian Institute of Technology DelhiNew Delhi 110016India Department of Mechanical Engineering Indian Institute of Technology DelhiNew Delhi 110016India School of Mechanical Engineering Vellore Institute of Technology UniversityVellore 632014India

The objective of this study was to relate experimental pressure fluctuation behavior to the transition in mode of flow observed in fluidized dense phase pneumatic conveying of fly *** entropy and wavelet analysis were utilized to extract features of the flow *** db4 wavelet analysis of pulsating air pressure revealed that the flow mechanism of fly ash in a fluidized dense phase possessed non-steady characteristics associated with gradual aeration of dunes along the direction of *** of Shannon entropy values along the length of the pipeline were assessed to determine the location at which the flow converted from dense to dilute phase *** effects of conveying parameters and specific power consumption on Shannon entropy and variations of the local power consumption coefficient are discussed.

关键词： Fluidized dense phase Mode transition Wavelet Shannon entropy

Digital twin in power system research and development:Principle,scope,and challenges

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy Reviews 2023年第3期2卷 84-98页

作者： Mohammed A.M.yassin Ashish Shrestha Suhaila Rabie Department of Electrical Engineering Information Technology and CyberneticsUniversity of South-Eastern NorwayPorsgrunnN-3918Norway

In order to address the issues that arise in modern power systems,such as system dynamics,stability,control,efficiency,reliability,economy,planning and policy,and so on,efforts have been made to develop new tools and techniques,components,methodologies,and scientific innovations in a variety of *** efforts have been undertaken to address these *** term“digital twin”(DT)refers to one of the most reliable and rapidly developing technologies that have recently been incorporated into a variety of applications,platforms,and realtime *** authors of this study offered a scoping review of DT technologies with a primary emphasis on power *** has been established that the underlying notion behind this technology,as well as its operating principle,types,communication channels and protocols,and standards,have all been thoroughly *** addition,the possibility of integrating other technologies with DT has also been considered,along with the potential benefits of doing so and the potential difficulties that may *** on the information gained from the current projects,the finished projects,the research publications,as well as the research and industry insights,a critical discussion has been made.

关键词： Communication channel Cyber-physical systems Digital twin Internet of things Machine learning

On thermodynamic self-consistency of generic axiomatic-nonextensive statistics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2017年第5期41卷 73-90页

作者： Abdel Nasser Tawfik Hayam yassin Eman R.Abo Elyazeed Egyptian Center for Theoretical Physics (ECTP) Modern University for Technology and Information (MTI) 11571 Cairo Egypt World Laboratory for Cosmology and Particle Physics (WLCAPP) 11571 Cairo Egypt Physics Department Faculty of Women for Arts Science and Education Ain Shams University 11577 Cairo Egypt

Generic axiomatic-nonextensive statistics introduces two asymptotic properties,to each of which a scaling function is *** first and second scaling properties are characterized by the exponents c and d,*** the thermodynamic limit,a grand-canonical ensemble can be *** thermodynamic properties of a relativistic ideal gas of hadron resonances are studied,*** is found that this generic statistics satisfies the requirements of the equilibrium *** aspects of the thermodynamic self-consistency are *** expressions are proposed for the statistical fits of various transverse momentum distributions measured in most-central collisions at different collision energies and colliding *** for the freezeout temperature（T_（ch）） and the baryon chemical potential（μ_b） and the exponents c and d are *** earlier are found compatible with the parameters deduced from Boltzmann-Gibbs（BG） statistics（extensive）,while the latter refer to generic *** resulting equivalence class（c,d） is associated with stretched exponentials,where Lambert function reaches its asymptotic *** some measurements,the resulting nonextensive entropy is linearly composed on extensive *** from power-scaling,the particle ratios and yields are excellent quantities to highlighting whether the particle production takes place（non）*** particle ratios and yields measured by the STAR experiment in central collisions at 200,62.4 and 7.7 GeV are fitted with this novel *** found that both c and d 〈 1,*** to neither BG-nor Tsallis-type statistics,but to（c,d）-entropy,where Lambert functions exponentially *** freezeout temperature and baryon chemical potential are found comparable with the ones deduced from BG statistics（extensive）.We conclude that the particle production at STAR energies is likely a nonextensive process but not necessarily BG or Tsallis

关键词： thermodynamic consistency asymptotic relativistic momentum quantities exponentially collision entropy generic

Workhorse flaps for thumb reconstruction

在线全文

学校读者我要写书评

暂无评论

Plastic and Aesthetic Research 2022年第1期9卷 48-64页

作者： Ahmed M.yassin Suvashis Dash Dariush Nikkhah Plastic Surgery Department Faculty of MedicineMansoura UniversityMansoura 35511Egypt Department of Plastic and Reconstructive Surgery All India Institute of Medical SciencesNew Delhi 110029India Division of Surgery&Interventional Science University College London UCLLondon NW32PFUK Department of Plastic Surgery Royal Free Hospital NHS Foundation TrustHampsteadLondon NW32QGUK

Posttraumatic thumb defects result in significant functional *** reconstructive procedures have been described for the management and improvement of *** with no treatment,all reconstructive methods are *** of the available procedures may be more applicable under certain conditions,can offer great benefits,and have its own downsides as *** a thorough assessment and meticulous technique,the results of thumb reconstruction can be *** present a review of the current reconstructive procedures for traumatic thumb amputation.

关键词： Thumb reconstruction soft tissue reconstruction of thumb thumb injury hand flaps

Anti-Müllerian hormone and antral follicle count predict ovarian response in women less than 45 years following GnRH antagonist multiple-dose protocol

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian pacific Journal of Reproduction 2022年第5期11卷 208-216页

作者： Mohammed M.Laqqan Maged M.yassin Department of Laboratory Medical Sciences Faculty of Health SciencesIslamic University of GazaP.O.Box 108GazaPalestine Department of Human Physiology Faculty of MedicineIslamic University of GazaP.O.Box 108GazaPalestine

Objective:To speculate which of the following parameters:antral follicle count(AFC),anti-Müllerian hormone(AMH),follicle-stimulating hormone(FSH)and age can be used as a predictor of ovarian response to gonadotropin-releasing hormone(GnRH)antagonist stimulation multiple-dose protocol in women under 45 years,and to determine the cutoff value of these parameters and their correlations for predicting low and high ovarian ***:This prospective study included 462 women with the mean age of(29.3±6.5)*** women were subjected to the GnRH antagonist stimulation multiple-dose *** the second day of the menstrual cycle,ultrasonography was conducted to determine AFC in both *** blood samples were collected to evaluate the level of estradiol,FSH,luteinizing hormone,prolactin,thyroid-stimulating hormone,and *** women were divided into three groups:low response(AHH3.5 ng/mL,n=114).Results:A significant decrease was found in the age and FSH level in the high response group compared to other groups(P<0.001).Conversely,a significant increase was shown in AMH,estradiol on human chorionic gonadotropin(hCG)day,AFC,mature oocytes,fertilized oocytes,and embryos transferred in the high response group compared to the other two groups(P<0.001).The receiver operating characteristic(ROC)curves demonstrated that AFC and AMH had the highest accuracy,followed by basal FSH level and age in the prediction of low ovarian reserves(P<0.001)with cutoff values of≤4.50 and≤0.95 for AFC and AMH,***,the ROC analysis showed that AFC had the highest accuracy,followed by AMH level and age in the prediction of high ovarian reserves with a cutoff value of≥14.50,≥3.63,and≤27.50 years,respectively(P<0.01).A significant decrease was observed in women's age,estradiol level,and oocyte fertilization rate in pregnant women compared to non-pregnant women(P<0.001).Additionally,sign

关键词： Antral follicle count Anti-Müllerian hormone Antagonist Controlled ovarian stimulation GnRH Multiple-dose Ovarian response

*** acknowledges the financial support from the Engineering and Physical Sciences Research Council(***/L022559/1,EP/L022559/2,EP/V050311/1,and EP/W004399/1);Royal Society(***130230 and IE161214);H2020 Marie Skłodowska-Curie Actions(No.790666);*** supported by a PhD Studentship provided by Queen Mary University of London and China Scholarship Council(CSC).

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2022年第8期15卷 7432-7452页

作者： Lumin Chen Somia yassin Hussain Abdalkarim Houyong Yu Xiang Chen Dongping Tang Yingzhan Li Kam Chiu Tam The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education Zhejiang Sci-Tech UniversityHangzhou 310018China Department of Chemical Engineering University of WaterlooWaterlooOntario N2L 3G1Canada

Advanced energy and sensor devices with novel applications(e.g.,mobile equipment,electric vehicles,and medical-healthcare systems)are one of the important foundations of modern intelligent ***,there are still some scientific issues that seriously hinder the further development of devices,including unsustainability,high material cost,complex fabrication process,safety issues,and unsatisfactory *** has aroused tremendous attention in recent decades,because of its abundant resources,renewability,degradability,low-cost,and unique physical/chemical *** merits make nanocellulose as matrix materials to fabricate advanced functional composites for use in energy-related fields extremely ***,we comprehensively discuss the recent progress of nanocellulose for emerging energy storage/harvesting and sensor *** preparation methodologies of nanocellulose combined with conductive materials are firstly highlighted,including carbon materials,conductive polymers,metal/metal oxide nanoparticles,metal-organic frameworks(MOFs),and covalent organic frameworks(COFs).We then focus on the nanocellulose-based advanced materials for the application in the areas of supercapacitors,lithium-ion batteries,solar cells,triboelectric nanogenerators,moisture-enabled electric generators,and ***,the future research directions of nanocellulose-based functional materials in energy-related devices are presented.

关键词： nanocellulose conductive composites supercapacitors lithium-ion batteries solar cells nanogenerators sensors

Photoelectrochemical evaluation of SILAR-deposited nanoporous BiVO4 photoanodes for solar-driven water splitting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Materials Science 2020年第3期2卷 227-234页

作者： Siti Nur'ain Haji yassin Adrian Soong Leong Sim James Robert Jennings Faculty of Science Universiti Brunei DarussalamJalan Tungku LinkBE 1410Brunei Darussalam

We report a photoelectrochemical investigation of BiVO4 photoanodes prepared by successive ionic layer adsorption and reaction(SILAR),a facile method that yields uniform nanoporous *** characterization of the phase,morphology,composition,and optical properties of the prepared films,the efficiencies of charge separation(ηsep)and water oxidation(ηox)in solar water splitting cells employing these photoanodes were estimated following a previously reported *** wavelength and illumination direction dependencies were discovered in the derived efficiencies,casting doubt on the validity of the *** alternative approach using a diffusion–reaction model that explicitly considers the efficiency of electron collection resolved the discrepancies and explained the illumination direction dependence of the *** diffusion lengths(Ln)of 0.45μm and 0.55μm were derived for pristine and cobalt phosphate(Co-Pi)modified BiVO4,respectively,which are much shorter than the film thickness of^2.1μ*** Co-Pi treatment also increasedηoxfrom 0.86 to^1,which is the main reason for the overall performance enhancement caused by adding *** findings suggest that there is little scope for improving the performance of SILAR-deposited BiVO4 photoanodes by further catalyzing water oxidation,but enhanced performance is achievable if electron transport can be improved.

关键词： Bismuth vanadate BiVO4 Solar water splitting Electron diffusion length Charge collection efficiency Water oxidation efficiency Charge separation efficiency