Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

The ultrafine scale microstructure of three MA/ODS ferritic alloys (12YWT, 14YWT and MA957) have been characterized by atom probe tomography in the as-received condition and after isothermal heat treatments at temperatures of up to 24 h at 1300 °C (∼85% T m ). Atom probe tomography revealed the presence of a high number density of 2–4 nm diameter titanium-, yttrium- and oxygen-enriched particles. These ultrafine particles were found to be extremely resistant to coarsening during isothermal aging at 1300 °C. Solute segregation of the alloying elements to dislocations and grain boundaries was also observed.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1431927604881169

Stability of Ferritic MA/ODS Alloys at High Temperatures

Algae waste is one of the potential substrates for biogas and biohydrogen production and can comprehend multiple benefits of waste treatment and resource utilization. In view of the key bottlenecks such as low substrate degradation rate and poor productivity of algae waste production process, this study analyzes the combined effect of two metallic and metallic oxide nanoparticles with different substrate pretreatment methods (autoclave, ultrasonic, and microwave methods) to investigate the effect of anaerobic digestion of green algae (Enteromorpha). The results showed that out of the three pretreatment methods, microwave pretreatment and nanoparticles' synergistic effect significantly increases biogas production. The microbial community composition at the phylum level was analyzed. It was observed that the Firmicutes were most abundant across all samples. The relative abundance of Firmicutes for control, Ni NPs + MW, Co NPs + MW, and Fe3O4 NPs + MW groups were 51.78, 70.37, 75.77, and 83.93%,      respectively. The second most abundant was of Bacteroidetes that also contributes to hydrogen production. This relatively high abundance of Firmicutes and Bacteroidetes promises its potential applications in a hydrogen production facility. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

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Nanoparticles Synergistic Effect with Various Substrate Pretreatment and their Comparison on Biogas Production from Algae Waste

DOI: http://doi.org/10.25130/tjes.27.2.09 ةرطيسلا ةيبوساحلا ىلع ةموظنم عبتت يسمش ةيئانث روحملا فلخ مولس ديعك / مسق ةسدنهلا ةيئابرهكلا / ةيلك ةسدنهلا / ةعماج تيركت / قارعلا ، دمحم ريصن نيدلا / ةسدنهلا مسق ةيئابرهكلا / ةسدنهلا ةيلك / ةعماج ديهكيل / ادنك دمحم ميرك دمحم / مسق ةسدنهلا ةيئابرهكلا / ةيلك ةسدنهلا / ةعماج تيركت / قارعلا ، رمع عفان دومحم / مسق ةسدنهلا ةيئابرهكلا / ةيلك ةسدنهلا / ةعماج تيركت / قارعلا ةصلاخلا نا ضرغلا يسيئرلا نم اذه لمعلا وه ميدقت ةركف موقت ىلع ميمصت ريوطتو ةموظنم بقعت ةقاطلا ةيسمشلا يئاقلتلا قيقحتل ىصقأ ردق نم جاتنا ةقاطلا اضيأو دحلل نم هجرد ةرارح ةحوللا ، ةدايزل ةءافكلا ةيئوضورهكلا ماق قيرفلا يف هذه ،ثحبلا ريوطتب ماظن عبتتلا يسمشلا يئاقلتلا ماظنل ةقاطلا ةيسمشلا ةريغصلا قاطنلا . دقو مت ريوطت ءزج ةزهجلأا ءزجو ةجمربلا يف تقو دحاو نم لجأ ماظن عبتت ةقاطلا ةيسمشلا لوصحلل ىلع ةموظنم لمعت ةقدب ةيلاع . مت لامعتسا ونيودرا ،ونوا ةمواقملا ةيئوضلا ( LDR ) ، ساسح هجرد ةرارحلا ( LM35 ) ، هحول ةيلاع ةءافكلا ةقاطلل ،ةيسمشلا تاكرحملا ةصاخلا ةرطيسلاب ىلع نحصلا مدختسملا طاقتللا ةراشإ ثب تاونقلا ،ةيئاضفلا جمانرب Protuse ةاكاحمل ةغل ةجمربلا ةيلاع يوتسملا دقو مت اهنيمضت يف ةزهجلأا ليغشتل ماظن عبتتلا ديربتلاو لكشب لاعف . دقو رهظا ماظن عبتتلا ديربتلاو ةيلاعف ةريبك يف ليصوت ةقاطلا ىلإ حاولأ ةقاطلا ةيسمشلا . :ةلادلا تاملكلا ،كمدلا ،ةيويحلا تارميلوبلا .ناثنزلا غمص ،صقلا ةمواقم ،ةيسبجلا ةبرتلا ،رايهنلاا ةيلامتحا

Design and Implement of Dual Axis Solar Tracker System Based Arduino

Molecular dynamics simulation of strengthening dependence on precipitate Cr composition in Fe-15at.%Cr alloy.

Sun energy is a considered to be one of most promising source to address the world energy crises. Photovoltaic cell is one of the prominent sources of energy. The most important factors that affect the efficiency of solar cells are cell temperature, maximum power point tracking (MPPT) and energy conversion efficiency. The optimization of these factors improves solar cells efficiency for more reliable applications. This study associated by means of the designing and manufacturing process of single axis tracker device by using photo voltaic conversion panels. This solar tracker system assures the conversion optimization of electricity from the source of sun energy by proper using of orientated photovoltaic panel in a manner conforming to the actual direction of sun. Experimental system based on the function of DC motor, which is controlled by dedicated drive astutely so as to move the PV panel in accordance with the signals be given as of effective light sensors. It has been found that at the same sunny day the energy output of solar panel with tracking system was 1742.88Wh and with non tracking system was 829.6Wh and

Design and Fabrication of Automatic Single Axis Solar Tracker for Solar Panel

In this study, we have investigated the effect of the grain boundary (GB) on the diffusion of a Phosphorus (P) atom in alpha-Fe using molecular dynamics simulations. A Fe-P mixed dumbbell is created in the six symmetric tilt grain boundary (STGB) models. The dumbbells are allowed to migrate at different temperatures from 400 K to 1000 K, with starting positions between 5 A to 10 A away from the GB core. The trajectories and mean square displacements (MSD) have been recorded to analyze the diffusion details. The Nudged Elastic Band (NEB) method has been used to study the energy barrier at different positions around the GBs. Our simulation results demonstrate that the GB structure affects the diffusion mechanisms of Fe-P dumbbell. The two low Σ favored GBs display significantly weak trapping effect, which is consistent with the formation energy distribution. The reduction in the migration barrier has been observed due to the decrease of distance from the GB center. Furthermore, the barriers of migration towards the GB are lower than the barriers of migration away from the GB. As evident by NEB calculation, absorption sink effect of GB has been observed. This effect saturates as the distance reaches 8 A or more. Our simulation results provide an insight into the GB trapping effect in alpha-Fe.

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Effect of Grain Boundary on Diffusion of P in Alpha-Fe: A Molecular Dynamics Study

Dislocation-oxide interaction in Y2O3 embedded Fe: A molecular dynamics simulation study

Radiation response of a material is a consequence of defects’ evolution in any radiation damage event. The radiation-induced defects can significantly alter the mechanical properties of a material. Radiation damage initiates from incident neutron by bombardment on solid material causing production and evolution of Frenkel defects. Since voids are formed due to aggregation of a large number of vacancies that cause dimensional changes and hence irradiation-induced swelling. In order to characterize the effect of irradiation defects, we have performed molecular dynamics (MD) simulations to investigate nanoindentation response of point defects and voids in Fe and their effects on mechanical parameters. The radial effect of voids and their interaction mechanism is also explored by nanoindentation simulation. It has been found that most of the dislocation produced are and during nanoindentation in all simulated models. There will be an increase in dislocation density which will harden the material and reduce its toughness. The mechanical parameters such as hardness H and reduced elastic modulus Er of irradiation defects are calculated from P-h curves. It is found that both H & Er of the point defects and voids are lower than the perfect model.

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M. Mustafa Azeem

Papers

Design and Fabrication of Automatic Single Axis Solar Tracker for Solar Panel

Effect of Grain Boundary on Diffusion of P in Alpha-Fe: A Molecular Dynamics Study

Dislocation-oxide interaction in Y2O3 embedded Fe: A molecular dynamics simulation study

Molecular dynamics simulation of strengthening dependence on precipitate Cr composition in Fe-15at.%Cr alloy.

Atomistic Simulations of Nanoindentation Response of Irradiation Defects in Iron