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Low temperature annealing of metals with electrical wind force effects

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Journal of Materials Science & Technology 2019年第4期35卷 465-472页

作者： Daudi Waryoba Zahabul islam Baoming Wang Aman Haque Engineering Applied MaterialsPenn State UniversityCollege Place Mechanical & Nuclear Engineering Penn State UniversityUniversity Park

Conventional annealing is a slow, high temperature process that involves heating atoms uniformly, i.e., in both defective and crystalline regions. This study explores an electrical alternative for energy efficiency,where moderate current density is used to generate electron wind force that produces the same outcome as the thermal annealing process. We demonstrate this on a zirconium alloy using in-situ electron back scattered diffraction(EBSD) inside a scanning electron microscope(SEM) and juxtaposing the results with that from thermal annealing. Contrary to common belief that resistive heating is the dominant factor, we show that 5 × 10~4 A/cm^2 current density can anneal the material in less than 15 min at only135?C. The resulting microstructure is essentially the same as that obtained with 600?C processing for360 min. We propose that unlike temperature, the electron wind force specifically targets the defective regions, which leads to unprecedented time and energy efficiency. This hypothesis was investigated with molecular dynamics simulation that implements mechanical equivalent of electron wind force to provide the atomistic insights on defect annihilation and grain growth.

关键词： Annealing Grain-growt Electron backscattered diffraction(EBSD) Molecular dynamics simulations Electron wind force

Composite Solid Rocket Propellant Based on GAP Polyurethane Matrix with Different Binder Contents

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火炸药学报 2020年第4期43卷 362-367页

作者： islam KBoshra Ahmed Elbeih GUO Lin Mohamed GZaki School of Chemistry and Environment Beihang UniversityBeijing 100191China Military Technical College Kobry ElkobbahCairoEgypt

Different GAP-based CSRP samples with different binder contents were prepared and compared with that of conventional HTPB *** crosslinker mixture of trimethylol propane(TMP)and butane diol(BD)was used in the GAP matrix beside the addition of dibutyltin dilaurate(DBTDL)to ensure cross-linking and curing completion of the prepared *** viscosity and hardness of all prepared formulations were monitored continuously during the curing *** mechanical characteristics of cured samples were *** burning rate at operating pressure and specific impulse were measured,while the theoretical specific impulse(i sp)was calculated by iCT code and compared with the measured *** to the results,DOA was found to be a suitable plasticizer for GAP when using in *** mechanical properties of CSRP with 25%GAP can produce the optimum mechanical behavior,which is close to that of HTPB-based *** optimum GAP-based formulation is one candidate to replace the traditional HTPB-based CSRP with high burning rate for some applications.

关键词： physical chemistry glycidyl azide polymer(GAP) hydroxyl terminated polybutadiene(HTPB) cross-linker mechanical properties

Origin of the regional stress field along the Liquine-Ofqui Fault Zone(LOFZ),Southern Chilean Andes by means of FE Simulation

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Journal of Mountain Science 2009年第1期6卷 1-13页

作者： Md.Rafiqul islam Department of Physics and Earth Sciences University of the RyukyusOkinawa 903-0213 Japan

The Liquine-Ofqui Fault Zone(LOFZ) of southern Chilean Andes is one of the largest active strike-slip fault *** is an ongoing debate regarding the origin of the stress field along the LOFZ due to its complex *** paper represents a study of the origins of the LOFZ regional stress *** fields are calculated by finite element(FE) *** two possible stress origins, i.e., oblique plate convergence and ridge collision/indenter tectonics of Chile ridge against Peru-Chile trench, have been emphasized in the present *** types of boundary conditions for the three particular models have been applied to calculate stress *** are assumed to be elastic and plane stress *** results are presented in terms of four parameters, i.e., orientation of maximum horizontal stress(σ H max ), displacement vector, s train distribution, and maximum shear stress(τmax ) contour line within the *** results of the first model with oblique plate convergence show inconsistency between the geometric shape of the LOFZ and the distribution of the four *** more realistic results are obtained from the second model with normal ridge collision, there are few coincident in the LOFZ geometry and regional stress *** third model with normal and oblique ridge collision is reasonable in understanding the origin of stress field and geometrical condition in the lithosphere of the LOFZ.

关键词： Liquine-Ofqui Fault Zone FE analysis Elastic rheology Oblique plate convergence Ridgecollision.

Artifact suppression and analysis of brain activities with electroencephalography signals

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Neural Regeneration Research 2013年第16期8卷 1500-1513页

作者： Md. Rashed-Al-Mahfuz Md. Rabiul islam Keikichi Hirose Md. Khademul islam Molla Department of Computer Science and Engineering Pabna University of Science and Technology Department of information and Communication Engineering The University of Tokyo Department of Computer Science and Engineering Rajshahi University

Brain-computer interface is a communication system that connects the brain with computer （or other devices） but is not dependent on the normal output of the brain （i.e., peripheral nerve and muscle）. Electro-oculogram is a dominant artifact which has a significant negative influence on further analysis of real electroencephalography data. This paper presented a data adaptive technique for artifact suppression and brain wave extraction from electroencephalography signals to detect regional brain activities. Empirical mode decomposition based adaptive thresholding approach was employed here to suppress the electro-oculogram artifact. Fractional Gaussian noise was used to determine the threshold level derived from the analysis data without any training. The purified electroencephalography signal was composed of the brain waves also called rhythmic components which represent the brain activities. The rhythmic components were extracted from each electroencephalography channel using adaptive wiener filter with the original scale. The regional brain activities were mapped on the basis of the spatial distribution of rhythmic components, and the results showed that different regions of the brain are activated in response to different stimuli. This research analyzed the activities of a single rhythmic component, alpha with respect to different motor imaginations. The experimental results showed that the proposed method is very efficient in artifact suppression and identifying individual motor imagery based on the activities of alpha component.

关键词： neural regeneration brain activity brain waves data adaptive filtering electroencephalography electro-oculogram artifact topographic mapping Wiener filtering neuroregeneration

Possibilities of urban flood reduction through distributed-scale rainwater harvesting

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Water Science and Engineering 2020年第2期13卷 95-105页

作者： Aysha Akter Ahad Hasan Tanim MdKamrul islam Department of Civil Engineering Chittagong University of Engineering&Technology(CUET)Chittagong 4349Bangladesh Center for River Harbor and Landslide ResearchChittagong University of Engineering&Technology(CUET)Chittagong 4349Bangladesh Department of Urban and Regional Planning Chittagong University of Engineering&Technology(CUET)Chittagong 4349Bangladesh

Urban flooding in Chittagong City usually occurs during the monsoon season and a rainwater harvesting(RWH)system can be used as a remedial *** study examines the feasibility of rain barrel RWH system at a distributed scale within an urbanized area located in the northwestern part of Chittagong City that experiences flash flooding on a regular *** flood modeling,the storm water management model(SWMM)was employed with rain barrel low-impact development(LiD)as a flood reduction *** Hydrologic Engineering Center's River Analysis System(HEC-RAS)inundation model was coupled with SWMM to observe the detailed and spatial extent of flood *** to SWMM simulated floods,the simulated inundation depth using remote sensing data and the HEC-RAS showed a reasonable match,i.e.,the correlation coefficients were found to be 0.70 and 0.98,***,using LiD,i.e.,RWH,a reduction of 28.66%could be achieved for reducing flood ***,the study showed that 10%e60%imperviousness of the subcatchment area can yield a monthly RWH potential of 0.04e0.45 m3 from a square meter of rooftop *** model can be used for necessary decision making for flood reduction and to establish a distributed RWH system in the study area.

关键词： Low-impact development(LiD) SWMM HEC-RAS Remote sensing Urban flooding inundation depth

A New Hybrid System Design for Thermal Energy Storage

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Journal of Thermal Science 2020年第5期29卷 1300-1308页

作者： CEYLA ilhan ALi ismail Hamad Guma ERGUN Alper GUREL Ali Etem ACAR Bahadir islam Nurse Department of Energy Systems Engineering Faculty of TechnologyKarabtik UniversityKarabik 78050Turkey Department of Mechanical and Manufacturing Engineering Faculty of TechnologyDuzce UniversityDtizce 81620Turkey

Due to some serious environmental problems like global warming and greenhouse effect,studies on solar energy systems are being conducted all over the *** studies conducted in recent years are on hybrid designs in which solar energy systems can realize both electricity and heat production at the same *** this way,both electrical energy and heat energy can be generated from the same system in this study,the design and analysis of a concentrated solar air collector with a heat storage unit were carried *** the solar air collector,heat energy was depot in paraffin wax,and the electrical energy which was stored in the battery using the PV(photovoltaic)modules in the system enabled the operation of the system *** experiments which aimed at determining system performance were carried out in winter when the ambient temperature was *** experiments were performed with or without a heat storage unit,and a comparative analysis was *** was found that the temperature of the air released from the collector ranged from 15°C to 40°C when the exterior temperature was-5°*** average efficiency of the concentrated system without the heat storage unit was calculated as 67%.The average efficiency of the concentrated system with the heat storage unit was calculated as 96%.

关键词： heat storage phase change material concentrated solar air collector

Cohesive Strength and Seismogenic Stress Pattern along the Active Basement Faults of the Precordillera-Sierras Pampeanas Ranges,Western Argentina:An Experimental Analysis by Means of Numerical Model

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Journal of Mountain Science 2009年第4期6卷 331-345页

作者： Md. Rafiqul islam Department of Physics and Earth Sciences Faculty of ScienceUniversity of the Ryukyus

A two-dimensional finite element method （FEM） model that incorporates faults, elastic rock physical properties, topographical load due to gravity and far-field plate velocity boundary conditions was used to recognize the seismogenic stress state along the fold-and-thrust belt of the Precordillera-Sierras Pampeanas ranges of western Argentina. A plane strain model with nine experiments was presented here to examine the fault strength with two major rock phyical properties： cohesion and angle of internal friction. Mohr-Coulomb failure criterion with bulk rock properties were applied to analyse faults. The stress field at any point of the model was assumed to be comprised of gravitational and tectonic components. The analysis was focused to recognize the seismogenic shear strain concentrated in the internal-cristaline domain of the orogene shown by the modeling. Modeling results are presented in terms of four parameters, i. e., （i） distributions, orientations, and magnitudes of principal stresses （σ1 and σ3）, （ii） displacement vector1 （iii） strain distribution, and （iv） maximum shear stress （τmax） contour line within the model. The simulation results show that the compressive stress is distributed in and around the fault systems. The overall orientation of of σ1 is in horizontal directions, although reorientations do occur within some stress weaker parts, especially subsequent to the faults. A large-scale shear stress is accumulating along the active faults of Tapias-Villicum Fault （TVF）, Salinas-Berros Fault （SBF）, Ampacama-Niquizanga Fault （ANF） and Las Charas Fault （CF）, which could act as local stress and strain modulators to localize the earthquakesoccurrence.

关键词： Finite element method Rock physical property Fold-and-thrust belt Fault strength Seismogenic shear stress pattern

Synthesis and reactions of 4-aryl-1(2H) phthalazinones

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Chinese Journal of Chemistry 1991年第1期9卷 45-53页

作者： SAYED,M.A. islam,i. MOHAMED,A.A. SOLiMAN,A.Y. BAKEER,H.M. Department of Chemistry Faculty of ScienceAin Shams and El-Azher UniversitiesEgypt Department of Chemistry Faculty of Education at FayoumCairo UniversityEgypt

The behavior of 4-aryl-1(2H)-phthalazinones (1a-c) toward some electrophilic and nucleophilic reagents has been described with the aim of preparing some new phthalazinone deriva- tives of the expected pharmacological ... 详细信息

关键词： Synthesis and reactions of 4-aryl-1 phthalazinones

improved voltage tracking of autonomous microgrid technology using a combined resonant controller with lead-lag compensator adopting negative imaginary theorem

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Protection and Control of Modern Power Systems 2022年第1期7卷 149-164页

作者： Md.Yah-Ya Ul Haque Md.Rashidul islam Tanvir Ahmed Md.Rafiqul islam Sheikh Department of Electrical and Electronic Engineering Varendra UniversityRajshahi 6204Bangladesh Department of Electrical and Electronic Engineering Rajshahi University of Engineering&TechnologyRajshahi 6204Bangladesh

Growing application of distributed generation units at remote places has led to the evolution of microgrid(MG)*** an MG system functions independently,i.e.,in autonomous mode,unpredictable loads and uncertainties emerge throughout the *** obtain stable and flexible operation of an autonomous MG,a rigid control mechanism is *** this paper,a robust high-performance controller is introduced to improve the performance of voltage tracking of an MG system and to eliminate stability problems.A combination of a resonant controller and a lead-lag compensator in a positive position feedback path is designed,one which obeys the negative imaginary(Ni)theorem,for both single-phase and three-phase autonomous MG *** controller has excellent tracking *** is investigated through considering various uncertainties with different load *** feasibility and effectiveness of the controller are also determined with a comparative analysis with some well-known controllers,such as linear quadratic regulator,model predictive and Ni approached resonant *** confirms the superi-ority of the designed controller.

关键词： Negative imaginary theorem Resonant controller Lead-lag compensator Autonomous microgrid Voltage tracking