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Impact of strain relaxation on the growth rate of heteroepitaxial germanium tin binary alloy

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Journal of Semiconductors 2024年第10期45卷 35-41页

作者： pedram Jahandar Maksym Myronov Department of Physics University of WarwickCoventryCV47ALUnited Kingdom

The growth of high-quality germanium tin(Ge_(1–y)Sn_(y))binary alloys on a Si substrate using chemical vapor deposition(CVD)techniques holds immense potential for advancing electronics and optoelectronics applications,including the development of efficient and low-cost mid-infrared detectors and light ***,achieving precise control over the Sn concentration and strain relaxation of the Ge_(1–y)Sn_(y)epilayer,which directly influence its optical and electrical properties,remain a significant *** this research,the effect of strain relaxation on the growth rate of Ge_(1–y)Sn_(y)epilayers,with Sn concentration>11at.%,is *** is successfully demonstrated that the growth rate slows down by~55%due to strain relaxation after passing its critical thickness,which suggests a reduction in the incorporation of Ge into Ge_(1–y)Sn_(y)growing *** the increase in Sn concentration as a result of the decrease in the growth rate,it has been found that the Sn incorporation rate into Ge_(1–y)Sn_(y)growing layers has also decreased due to strain *** valuable insights could offer a foundation for the development of innovative growth techniques aimed at achieving high-quality Ge_(1–y)Sn_(y)epilayers with tuned Sn concentration and strain relaxation.

关键词： GeSn germanium tin strain relaxation groupⅣsemiconductor chemical vapour deposition CVD

Identification of time-varying system and energy-based optimization of adaptive control in seismically excited structure

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 227-240页

作者： Elham Aghabarari Fereidoun Amini pedram Ghaderi Department of Civil Engineering Iran University of Science and TechnologyTehran 16844Iran

The combination of structural health monitoring and vibration control is of great importance to provide components of smart *** synthetic algorithms have been proposed,adaptive control that is compatible with changing conditions still needs to be used,and time-varying systems are required to be simultaneously estimated with the application of adaptive *** this research,the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are ***,reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares(MFRLS)***,the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be *** is also performed based on the probability density function of the energy under the seismic excitation at any ***,the optimal control force is obtained by the simple adaptive control(SAC)algorithm and energy coefficient.A numerical example and benchmark structure are employed to investigate the efficiency of the proposed *** simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.

关键词： integrated online identification time-varying systems structural energy multiple forgetting factor recursive least squares optimal simple adaptive control algorithm

Quantifying the thermal damping effect in underground vertical shafts using the nonlinear autoregressive with external input(NARX) algorithm

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International Journal of Mining Science and Technology 2019年第2期29卷 255-262页

作者： pedram Roghanchi Karoly C.Kocsis Mineral Engineering Derpartment New Mexico Institute of Mining and Technology Mining Engineering Derpartment University of Nevada

As air descends the intake shaft, its infrastructure, lining and the strata will emit heat during the night when the intake air is cool and, on the contrary, will absorb heat during the day when the temperature of the air becomes greater than that of the strata. This cyclic phenomenon, also known as the "thermal damping effect" will continue throughout the year reducing the effect of surface air temperature variation. The objective of this paper is to quantify the thermal damping effect in vertical underground airways. A nonlinear autoregressive time series with external input(NARX) algorithm was used as a novel method to predict the dry-bulb temperature(Td) at the bottom of intake shafts as a function of surface air temperature. Analyses demonstrated that the artificial neural network(ANN) model could accurately predict the temperature at the bottom of a shaft. Furthermore, an attempt was made to quantify typical "damping coefficient" for both production and ventilation shafts through simple linear regression models. Comparisons between the collected climatic data and the regression-based predictions show that a simple linear regression model provides an acceptable accuracy when predicting the Tdat the bottom of intake shafts.

关键词： Underground mining Vertical openings Thermal damping effect Artificial neural network Nonlinear autoregressive with external input(NARX)

Correlations between direct and indirect strength test methods

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International Journal of Mining Science and Technology 2015年第3期25卷 355-360页

作者： Kallu Raj Roghanchi pedram Department of Mining Engineering University of Nevada

The difficulties associated with performing direct compression strength tests on rocks lead to the development of indirect test methods for the rock strength assessment. Indirect test methods are simple, more economical, less time-consuming, and easily adaptable to the field. The main aim of this study was to derive correlations between direct and indirect test methods for basalt and rhyolite rock types from Carlin trend deposits in Nevada. In the destructive methods, point load index, block punch index, and splitting tensile strength tests are performed. In the non-destructive methods, Schmidt hammer and ultrasonic pulse velocity tests are performed. Correlations between the direct and indirect compression strength tests are developed using linear and nonlinear regression analysis methods. The results show that the splitting tensile strength has the best correlation with the uniaxial compression ***, the Poisson's ratio has no correlation with any of the direct and indirect test results.

关键词： Uniaxial compression strength test Indirect strength test methods Correlation Regression analysis

In-situ polymerization of lignocelluloses of autohydrolysis process with acrylamide

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Journal of Bioresources and Bioproducts 2023年第3期8卷 235-245页

作者： Haosong Zhao Weijue Gao pedram Fatehi Biorefining Research Institute and Chemical Engineering Department Lakehead UniversityThunder Bay P7B 5E1Canada

In the present study,the hydrolysates generated via autohydrolysis of spruce wood chips were di-rectly used as feedstock for producing *** in-situ polymerization of acrylamide(AM)and lignocellulose(LC)of hydrolysates was successfully *** reaction was optimized to generate lignocellulose-acrylamide(LC-AM)with the highest molecular weight(41,060 g/mol)and charge density(-0.25 meq/g)under the optimum conditions,which were 3 h,60◦C,4%(w)initiator based on the dried mass of hydrolysate,and an AM/LC molar ratio of 5.63.A nuclear magnetic resonance(NMR)spectroscopy confirmed the grafting of acrylamide on *** prop-erties of LC-AM were characterized by the elemental analyzer,zeta potential analyzer,gel per-meation chromatography(GPC),and particle charge detector(PCD).The LC-AM was applied as a coagulant for removing ethyl violet dye from a simulated dye *** results indicated that 47.2%dye was removed from the solution at a low dosage of 0.2 g/*** dual flocculation of LC-AM with other polymers for dye removal is suggested to further improve its effectiveness.

关键词： Polymerization Hydrolysate Lignocellulose Acrylamide Biorefining

Synthetic and lignin-based surfactants:Challenges and opportunities

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Carbon Resources Conversion 2018年第2期1卷 126-138页

作者： Norah Alwadani pedram Fatehi Chemical Engineering Department Lakehead University955 Oliver RoadThunder BayOntario P7B5E1Canada

Surface active agents(surfactants)are chemicals that can accumulate at the surface of a liquid,or interface between two phases with the role of changing the surface tension of the *** on their structures,they have many applications in industries,such as the petroleum,mining,pulping and textiles,wherein they are utilized as detergents,wetting agents,emulsifiers,foaming agents and *** of commonly used surfactants are oil-based ***,using environmentally friendly feedstocks to produce surfactant is desirable to lessen the environmental impact of surfactant production and use in *** is an attractive candidate for this purpose as it is inexpensive and readily *** and lignin derivatives,such as lignosulfonates,can be chemically modified to produce surfactants with different chemical and physical properties,which makes them suitable for a wide variety of *** lignin types and the processes performed for lignin production affect the properties of generated lignin significantly,which in turn influence the reactivity and the efficiency of the reaction for surfactant *** this review,the characteristics and applications of oil-based surfactants,and the efforts to produce lignin-based surfactants are *** oil-based surfactants with altered properties are available in the market,several different pathways can be followed for producing lignin-based *** advantages and disadvantages of using lignin-based surfactants are also discussed.

关键词： Lignin Surfactant Lignosulfonate Biorefining Organic materials

Fuel efficiency optimization of tanker with focus on hull parameters

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Journal of Ocean Engineering and Science 2017年第2期2卷 76-82页

作者： pedram Edalat Amirhossein Barzandeh Faculty of Marine Engineering Petroleum University of TechnologyMahmudabadIran

Fuel efficiency optimization is of crucial importance in *** transportation industry is no ***-disciplinary optimization is a branch of engineering which uses optimization methods for solving problems in which the objective function is simultaneously affected by several different *** one of the tools for this type of optimization,genetic algorithm has a high quality and *** objective of the present study is to optimize fuel efficiency in *** presented equations and conditions are valid for *** consumption efficiency of tankers is a function of various influential *** the lack of equations for describing and modeling these factors and unavailability of valid performance database for inferring the equations as well as the lack of literature in this field,the preset study includes five optimizing factors affecting the fuel consumption efficiency of a tanker in genetic algorithm by using the genetic algorithm toolbox of MATLAB software package.

关键词： Fuel consumption efficiency Tanker Multi-disciplinary optimization Genetic algorithm Hull parameters

Mechanical properties and in vivo biodegradability of Mg-Zr-Y-Nd-La magnesium alloy produced by a combined severe plastic deformation

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Rare Metals 2021年第3期40卷 651-662页

作者： A.Torkian G.Faraji M.S.pedram School of Mechanical Engineering College of EngineeringUniversity of TehranTehran 11155-4563Iran Department of Veterinary Surgery and Radiology Faculty of Veterinary MedicineUniversity of Tehran14199-63111Iran

Permanent implants are going to be replaced by the implementation of biodegradable magnesium-based implants in fixation of internal bone fractures because of many concerns associated with conventional ***,biodegradable magnesium-based biomaterials exhibit higher biodegradation rate and low mechanical properties which are the main *** work aims to almost overcome both disadvantageous by grain refining of a WE43 magnesium alloy containing 93.04 wt% Mg,4.12 wt% Y,2.15 wt% Nd,0.43 wt% Zr,and 0.26 wt%*** this study,the consequences of combined severe plastic deformation(SPD) on the mechanical properties,microstructure,and in vivo degradation behavior of WE43 magnesium alloy were *** do so,WE43 magnesium alloy was chosen and processed through multipass equal channel angular pressing(ECAP) at 330℃ for up to four passes followed by an extrusion *** results showed that higher strength and hardness with minimum ductility less was obtained in the sample processed via two-pass ECAP followed by *** vivo biodegradation experiments showed higher degradation rate for the unprocessed coarse-grained(CG) WE43 *** two-pass ECAP and extruded sample with ultrafine-grained(UFG) structure exhibited the lowest in vivo biodegradation rate besides appropriate mechanical *** may be concluded that the WE43 magnesium alloy processed via two-pass ECAP and extrusion could be a very promising candidate for biodegradable implants from both mechanical and biocorrosion viewpoints.

关键词： Implant Severe plastic deformation WE43 Grain refinement Hardness Mechanical properties

Enrichment and immobilization of macromolecular analytes on a porous membrane utilizing permeation drag

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Journal of Pharmaceutical Analysis 2018年第3期8卷 187-193页

作者： pedram Madadkar Rahul Sadavarte Raja Ghosh Department of Chemical Engineering Mc Master University

Enrichment and immobilization of analytes by chemical bonding or physical adsorption is typically the first step in many commonly used analytical techniques. In this paper, we discuss a permeation drag based technique as an alternative approach for carrying out location-specific immobilization of macro- molecular analytes. Fluorescein isothiocyanate （FITC） labeled macromolecules and their complexes were enriched near the surface of ultrafiltration membranes and detected by direct visual observation and fluorescence imaging. The level of macromolecule enrichment at the immobilization sites could be controlled by manipulating the filtration rate and thereby the magnitude of permeation drag. Higher enrichment as indicated by higher fluorescence intensity was observed at higher filtration rates. Also, larger macromolecules were more easily enriched. The feasibility of using this technique for detecting immunocomplexes was demonstrated by carrying out experiments with FITC labeled bovine serum al- bumin （FITC-BSA） and its corresponding antibody. This permeation drag based enrichment technique could potentially be developed further to suit a range of analytical applications involving more sophis- ticated detection methods.

关键词： Macromolecule Enrichment Immobilization Concentration polarization Permeation draglmmunoassay Membrane Ultrafiltration