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Numerical investigation of Reynolds number and scaling effects in microchannels flows

Journal of Hydrodynamics 2017年第4期29卷 647-658页

作者： s.A.si salah E.g.Filali s.Djellouli Faculty of Mechanical and Process Engineering Houari Boumedienne University

Compared with conventional channels, experiments of microchannel often exhibit some controversial findings and sometimes even opposite trends, most notably the effects of the Reynolds number and the scaled channel height on the Poiseuille number. The experimental method has still been constrained by two key facts, firstly the current ability to machine microstructures and secondly the limitation of measurement of parameters related to the Poiseuille number. As a consequence, numerical method was adopted in this study in order to analyze a flow in two-dimensional rectangular microchannels using water as working fluid. Results are obtained by the solution of the steady laminar incompressible Navier-stokes equations using control volume finite element method（CVFEM） without pressure correction. The computation was made for channel height ranging from 50 ？m to 4.58 ？m and Reynolds number varying from 0.4 to 1 600. The effect of Reynolds number and channel heights on flow characteristics was investigated. The results showed that the Poiseuille numbers agree fairly well with the experimental measurements proving that there is no scale effect at small channel height. This scaling effect has been confirmed by two additional simulations being carried out at channel heights of 2.5 ？m and 0.5 ？m, respectively and the range of Reynolds number was extended from 0.01 up to 1 600. This study confirm that the conventional analysis approach can be employed with confidence for predicting flow behavior in microchannels when coupled with carefully matched entrance and boundary conditions in the dimensional range considered here.

关键词： Rectangular microchannel Poiseuille number control volume finite element method(CVFEM) laminar flow minichannels

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Dynamic Fracture Toughness of Armour grade Quenched and Tempered steel Joints Fabricated Using Low Hydrogen Ferritic Fillers

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Journal of Iron and steel Research International 2010年第5期17卷 51-56页

作者： g Magudeeswaran V Balasubramanian s sathyanarayanan g Madhusudhan Reddy A Moitra s Venugopal g sasikala Department of Mechanical Engineering Pannaikkadu Veerammal Paramasivam College of Engineering andTechnology for Women Department of Manufacturing Engineering Annamalai University Materials Mechanics section Indira Gandhi Center for Atomic Research Metal Joiningsection Defence Metallurgical Research Laboratory

The armour grade quenched and tempered steel joints fabricated using low hydrogen ferritic steel （LHF） filler exhibited superior joint efficiency owing to preferential ferrite microstructure in the welds and also they offered required resistance to HIC. However, the combat vehicles used in military operations will be required to operate under a wide range of road conditions ranging from first class to cross country. structural components in combat vehicles are subjected to dynamic loading with high strain rates during operation. stress loadings within the vehicle hull of these vehicles are expected to fluctuate considerably and structural cracking especially in welds during the service life of these vehicles can lead to catastrophic failures. Under these conditions, fracture behaviour of high strain rate sensitive structural steels can be better understood by dynamic fracture toughness （K1d）. Hence, an attempt was made to study dynamic fracture toughness of the armour grade quenched and tempered steel and their welds fabricated using LHF consumables. The experimental results indicate that the K1d values of the joints fabricated by shielded metal arc welding （sMAW） are higher than those of the joints fabricated using flux cored arc welding （FCAW） process.

关键词： quenched steel tempered steel low hydrogen ferritic steel dynamic fracture toughness

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The Relationship Between Developmental Accumulation of Leaf soluble Proteins and Vernalization Response of Wheat(Triticum aestivum ***. Thell)

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Agricultural sciences in China 2009年第4期8卷 410-417页

作者： M Majdi g Karimzadeh s Mahfoozi Plant Breeding and Biotechnology Department Faculty of AgricultureTarbiat Modares UniversityP.O.Box 14115-336Tehran ***Iran Physiology-Agronomy Unit of Department of Cereals Research Seed and Plant Improvement InstituteKaraj 315854119Iran

The relationship between vernalization requirement and quantitative and qualitative changes in total leaf soluble proteins were determined in one spring （cv. Kohdasht） and two winter （cvs. sardari and Norstar） cultivars of wheat （Triticum aestivum L.） exposed to 4℃. Plants were sampled on days 2, 14, 21 and 35 of exposure to 4℃. The final leaf number （FLN） was determined throughout the vernalization periods （0, 7, 14, 24, and 35 d） at 4℃. The final leaf number decreased until days 24 and 35 in sardari and Norstar eultivars, respectively, indicating the vernalization saturation at these times. No clear changes were detected in the final leaf number of Kohdash cultivar, verifying no vernalization requirement for this spring wheat cultivar. Comparing with control, clear cold-induced 2-fold increases in proteins quantity occurred after 48 h following the 4℃-treatment in the leaves of the both winter wheat cultivars but, such response was not detected in the spring cultivar. However, the electrophoretic protein patterns showed between-cultivar and between-temperature treatment differences. With increasing exposure time to 4℃, the winter cultivars tended to produce more HMW polypeptides than the spring cultivar. similar proteins were induced in both sardari and Norstar winter wheat cultivars, however, the long vernalization requirement in Norstar resulted in high level and longer duration of expression of cold-induced proteins compared to sardari with a short vernalization requirement. These observations indicate that vernalization response regulates the expression of low temperature （LT） tolerance proteins and determines the duration of expression of LT- induced proteins.

关键词： soluble proteins wheat Triticum aestivum L. final leaf number vernalization cold

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Virtual Nursing Using Deep Belief Networks for Elderly People (DBN-EP)

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Computer systems science & Engineering 2022年第9期42卷 985-1000页

作者： s.Rajasekaran g.Kousalya Department of Information Technology KGiSL Institute of TechnologyCoimbatore641035India Department of Computer science and Engineering Coimbatore Institute of TechnologyCoimbatore641014India

The demand for better health services has resulted in the advancementof remote monitoring health, i.e., virtual nursing systems, to watch and supportthe elderly with innovative concepts such as being patient-centric, easier to use,and having smarter interactions and more accurate conclusions. While virtual nursing services attempt to provide consumers and medical practitioners with continuous medical and health monitoring services, access to allied healthcare expertssuch as nurses remains a challenge. In this research, we present Virtual NursingUsing Deep Belief Networks for Elderly People (DBN-EP), a new framework thatprovides a virtual nurse agent deployed on a senior citizen’s home, workplace, orcare centre to help manage their health condition on a continuous basis. Using thismethod, healthcare providers can assign various jobs to nurses by utilizing a general task definition mechanism, in which a task is defined as a combination ofmedical workflow, operational guidelines, and data gathered from a remotelymonitored virtual nursing system. Practitioners are in charge of DBN-EP andmake treatment decisions for patients. This allows a DBN-EP to act as a personalized full-time nurse for a client by carrying out practitioner support activitiesbased on information gathered about the client’s health. An electronic PersonalHealth Record (ePHR) system, such as a specialized web portal and mobile apps,could provide such patient information to elderly person family members and carecentres. We created a prototype system using a DBN-EP system that allows traditional client applications and healthcare provider systems to collaborate. Finally,we demonstrate how this system may benefit the elderly through a result anddebate.

关键词： Deep belief networks RBM video mining elder people elder care

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Novel electrocardiographic dyssynchrony criteria that may improve patient selection for cardiac resynchronization therapy

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Journal of geriatric Cardiology 2022年第1期19卷 31-43页

作者： gábor Katona András Vereckei Department of Medicine and Hematology Semmelweis UniversityBudapestHungary

Cardiac resynchronization therapy(CRT)is an evidence-based effective therapy of symptomatic heart failure with reduced ejection fraction refractory to optimal medical treatment associated with intraventricular conduction disturbance,that results in electrical dyssynchrony and further deterioration of systolic ventricular ***,the non-response rate to CRT is still 20%−40%,which can be decreased by better patient *** main determinant of CRT outcome is the presence or absence of significant ventricular dyssynchrony and the ability of the applied CRT technique to eliminate *** current guidelines recommend the determination of QRs morphology and QRs duration and the measurement of left ventricular ejection fraction for patient selection for ***,QRs morphology and QRs duration are not perfect indicators of electrical dyssynchrony,which is the cause of the not negligible non-response rate to CRT and the missed CRT implantation in a significant number of patients who have the appropriate substrate for *** imaging modalities,many ventricular dyssynchrony criteria were devised for the detection of mechanical dyssynchrony,but their utility in patient selection for CRT is not yet proven,therefore their use is not recommended for this ***,CRT can eliminate only mechanical dyssynchrony due to underlying electrical dyssynchrony,for this reason ECg has a greater role in the detection of ventricular dyssynchrony than imaging *** improve assessment of electrical dyssynchrony,we devised two novel ECg dyssynchrony criteria,which can estimate interventricular and left ventricular intraventricular dyssynchrony in order to improve patient selection for *** we discuss the results achieved by the application of these new ECg dyssynchrony criteria,which proved to be useful in predicting the CRT response in patients with nonspecific intraventricular conduction disturbance pattern(the second greatest group of CRT candidates),an

关键词： patient synchronization eliminate

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synthesis of mesostructured thin films by ionic wind assisted electrostatic spray deposition

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Particuology 2016年第4期14卷 128-132页

作者： s. Khodadadi g.M.H. Meesters g. Biskos Faculty of Applied sciences Delft University of Technology Delft 2628-BL Netherlands Faculty of Civil Engineering and geosciences Delft University of Technology Delft 2628-CN Netherlands Energy Environment and Water Research Center The Cyprus Institute Hicosia 2121 Cyprus

Thin films produced by electrostatic spray deposition （EsD） have nanometer-sized structures despite the initial sprayed droplets being typically a few tens of microns in diameter. The size and morphology of the resulting structures is not only affected by the solvent properties and drying kinetics, hut also by Coulomb fission owing to the high surface charge density that the droplets build up upon evaporation. In this work we modulate the charge density of the droplets by inducing ionic wind along the spray, and produce mesoscopic structures. Using WO3 as an example, we show that the technique provides a practical way to control the morphology of thin films produced by EsD.

关键词： Electrohydrodynamic atomization Electrospray Aerosol Tungsten oxide Porous thin film

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Performance Analysis of Intelligent Robust Facility Layout Design

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Chinese Journal of Mechanical Engineering 2017年第2期30卷 407-418页

作者： g MOsLEMIPOUR T s LEE Y T LOONg Department of Industrial Engineering Payame Noor University Faculty of Engineering and Technology Multimedia University

Design of a robust production facility layout with minimum handling cost （MHC） presents an appropriate approach to tackle facility layout problems in a dynamic volatile environment, in which product demands randomly change in each planning period. The objective of the design is to find the robust facility layout with minimum total material handling cost over the entire multiperiod planning horizon. This paper proposes a new mathematical model for designing robust machine layout in the stochastic dynamic environment of manufacturing systems using quadratic assignment problem （QAP） formulation. In this investigation, product demands are assumed to be normally distributed random variables with known expected value, variance, and covariance that randomly change from period to period. The proposed model was verified and validated using randomly generated numerical data and benchmark examples. The effect of dependent product demands and varying interest rate on the total cost function of the proposed model has also been investigated. sensitivity analysis on the proposed model has been performed. Dynamic programming and simulated annealing optimization algorithms were used in solving the modeled example problems.

关键词： Robust layout Dynamic stochastic environment Manufacturing system Dynamic programming

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Bake-Hardening Response of High Martensite Dual-Phase steel with Different Morphologies and Volume Fractions

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Acta Metallurgica sinica(English Letters) 2014年第2期27卷 279-289页

作者： Mustafa Trkmen sleyman gndz Department of Metallurgy Kocaeli University Hereke Vocational School Department of Manufacturing Engineering Technology FacultyKarabk University

Bake-hardening behaviour of carbon steel with different martensite morphologies and volume fraction was investigated. The specimens with fibrous and bulky martensite were prestrained in tension by 4%. After this, they were unloaded and bake hardened at 180 ℃ for 10-160 min. It was found that dual-phase steel samples which were bake hardened at 180 ℃ for 20 rain showed an increase in the yield stress （Ys） and ultimate tensile stress （UTs） but a decrease in ductility. Further increase in the bake-hardening time of 80 or 160 min has reduced the Ys and UTs, but increased the ductility. △σ （increase in stress due to bake hardening）, Ys and UTs values are higher for the microstructure containing fibrous martensite compared to the microstructure-containing bulky martensite. It was also observed that at a given baking temperature Aa, Ys and UTs increased by volume of martensite.

关键词： Dual-phase steel Bake hardening Martensitic transformation

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structure modeling of terbium doped strontium-lanthanum borate

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Journal of Rare Earths 2014年第3期32卷 248-253页

作者： A.shyichuk s.Lis g.Meinrath Department of Rare Earths Faculty of Chemistry Adam Mickiewicz University Radioactivity Environment Remediation (RER) Consultants

Terbium doped strontium-lanthanum borate, sr3La2（BO3）4：Tb （sLB）, was studied by semi-empirical computational ap- proaches using PM6 parametrization and the sPARKLE model for lanthanide（Ⅲ）（Ln（Ⅲ）） cations. The focus of interest was on structural aspects, e.g. the cell parameters and distribution of dopant ions between various sites as a function of dopant concentration. The cell linear dimensions were calculated to decrease linearly with increasing dopant molar concentration. sLB offered two sites for the dopant. Calculations predicted that one of these sites should be preferred by the Tb（Ⅲ） dopant. The optimized cell dimensions as well as the total energies differed for structures with dopant exclusively in site 1 or site 2. Computational predictions were tested against experimental results obtained for sLB synthesized by sol-gel method varying the dopant concentration. The agreement be- tween experimental and computational results was found sufficiently promising to continue the computational studies.

关键词： strontium-lanthanum borate terbium structure calculations rare earths

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Effect of Welding Processes and Consumables on Tensile and Impact Properties of High strength Quenched and Tempered steel Joints

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Journal of Iron and steel Research International 2008年第6期15卷 87-94页

作者： g Magudeeswaran V Balasubramanian g Madhusudhan Reddy T s Balasubramanian Center for Advanced Materials Joining and Research(CEMAJOR) Department of Manufacturing EngineeringAnnamalai University Metal Joining section Defence MetallurgicalResearch Laboratory special Vehicles Division Combat Vehicles Research and Development Establishment

Quenched and tempered steels are prone to hydrogen induced cracking in the heat affected zone after welding. The use of austenitic stainless steel consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase. In this investigation, an attempt was made to determine a suitable consumable to replace expensive austenitic consumables. Two different consumables, namely, austenitie stain less steel and low hydrogen ferritic steel, were used to fabricate the joints by shielded metal are welding （sMAW） and flux cored arc welding （FCAW） processes. The joints fabricated by using low hydrogen ferritic steel consumables showed superior transverse tensile properties, whereas joints fabricated by using austenitic stainless steel consumables exhibited better impact toughness, irrespective of the welding process used. The sMAW joints exhibited superior mechanical and impact properties, irrespective of the consumables used, than their FCAW counterparts.

关键词： shielded metal arc welding process flux cored arc welding process austenitie stainless steel low hydro gen ferritic steel transverse tensile property impact toughness

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