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A magneto -thermo-elastic problem for a half-space without energy dissipation subjected to rotation and gravity field

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Journal of Ocean Engineering and science 2019年第1期4卷 55-63页

作者： A.m.Abd-Alla s.m.Abo-Dahab s.m.ahmed m.m.Rashid Faculty of science Mathematics DepartmentSohag UniversityEgypt Faculty of science Mathematics DepartmentSouth Valley UniversityQena 83523Egypt Faculty of science Mathematics DepartmentTaif University888Saudi Arabia Faculty of science Mathematics DepartmentAl-Arish UniversityEgypt

The prime objective of the present paper is to analyze the effects of the rotation,magnetic field and gravity in a thermo-elastic half-space containing heat source on the boundary of the *** medium assumed under consideration is traction free,homogeneous,isotropic,as well as without energy *** normal mode analysis and eigenvalue approach technique are used to solve the resulting non-dimensional coupled *** comparisons for the physical quantities are established numerically and represented graphically in different cases with respect to the used effects.A comparative and remarkable study has been carried out through various graphs to deliberate the consequences of different parameter on the displacement components,stress components and temperature.

关键词： Green-Naghdi theory Thermo-elasticity Energy dissipation Rotation magnetic field Gravity field.

Community microgrid:an approach towards positive energy community in an urban area of Dhaka,Bangladesh

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Clean Energy 2023年第4期7卷 926-939页

作者： mohammad Zeyad s.m.masum ahmed sayeed Hasan Dewan mahnaaz mahmud Energy and Technology Research Division Advanced BioinformaticsComputational Biology and Data Science LaboratoryBangladesh(ABCD LaboratoryBangladesh)House:24Road:01Block:BHalishaharChattogram 4226Bangladesh school of Engineering and Physical sciences(EPs) Heriot-Watt UniversityCampus The AvenueEdinburghScotland EH144ASUK Department of Energy Engineering University of the Basque Country(UPV/EHU)Ingeniero Torres Quevedo Plaza1BilbaoBiscay 48013Spain Department of Electrical Electronic and Control EngineeringSchool of Industrial EngineeringUniversity of ExtremaduraCampus UniversitarioAv.de Elvass/nBadajozBadajoz 06006Spain Centre for Research on Geography ResourcesEnvironmentEnergy and Networks(Green)Bocconi UniversityVia Roentgen 1MilanoLombardy 20136Italy Control and Robotics(CORO) Ecole Centrale De Nantes1 Rue de la No?44300 NantesFrance

The pollution and toxic greenhouse gases produced by fossil fuel combustion are troubling as global energy demand continues to *** mitigate the consequences of global warming,a transition to sustainable energy sources is *** manuscript presents a feasible community microgrid design in Hazaribagh,Dhaka based on meteorological data that leads to photovoltaic installation on the rooftop of a local community *** study shows a microgrid design of a system with the lowest cost of energy and a large renewable fraction,which is analysed using the HOmER Pro *** real-time data,analysis of the system cost,cost of energy,renewable fraction,unmet load,energy purchased and energy sold is discussed.A suitable case for electrification is also identified and presented for the selected *** proposed case yields a cost of energy of$0.0357/kWh,which is 52%less than the current tariff rate,with a 70%renewable *** study will provide people in this community with more green energy at a lower cost;in addition,this designed microgrid sells additional energy to the grid to avoid possible power *** potential for a positive energy community is also investigated in terms of energy consumption and renewable output of the planned microgrid.

关键词： cost of energy microgrid positive energy community renewable fraction

Grid-connected microgrid:design and feasibility analysis for a local community in Bangladesh

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Clean Energy 2022年第3期6卷 447-459页

作者： Dewan mahnaaz mahmud s.m.masum ahmed sayeed Hasan mohammad Zeyad Energy and Technology Research Division Advanced BioinformaticsComputational Biology and Data Science LaboratoryBangladesh Faculty of Engineering Erasmus Mundus Joint MSc in Smart Cities and Communities(SMACCs)University of Mons(UMONS)Belgium school of Engineering and Physical sciences(EPs) Erasmus Mundus Joint MSc in Smart Cities and Communities(SMACCs)Heriot-Watt University(HWU)UK

Global demand for electricity is growing significantly in developing *** energy accounts for barely 3%of total energy consumption in *** of renewable energy,***,are increasingly being acknowledged as viable supply-side choices for *** article presents a grid-connected microgrid design based on meteorological data for a local community situated in mohammadpur,*** study presents a feasible design of a system that gives the lowest cost of energy production and emissions that is evaluated using software named Hybrid Optimization multiple Energy Resources(HOmER Pro).Comparison and assessment of the net present cost,cost of energy,operating cost and environmental emission for five different feasible microgrids are analysed concerning real-time ***,a suitable case is sorted out and proposed for the local community for *** proposed case offers a$0.0442/kWh cost of energy,which is~32%cheaper than the current rate with a 57.5%renewable fraction and a payback period of 16.86 *** of this local community will have access to considerably more clean energy at a lower price by this study;also this design could sell the excess energy to the grid to avoid frequent electricity outages.

关键词： renewable energy communities microgrid community energy photovoltaic batteries emission cost of energy

Performance Characteristics of single Cylinder Diesel Engine under Different Operating Conditions

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Journal of Environmental science and Engineering 2011年第7期5卷 850-856页

作者： H.A. mohamed m.s. ahmed Faculty of Engineering Assiut Universiy Assiut 71516 Egypt Faculty of lndustrial Education Sohag University Sohag 71516 Egypt

Recently, it is predicted that the fossil fuels will be sufficient for a few decades at the present extraction rates. so, the performance studies of the internal combustion engines play an important role to achieve the best operating point at different weather temperatures. In the present study, the effects of the inlet air temperatures on the engine performance characteristics were studied at different cooling loads. several experiments were carried out on a single cylinder diesel engine （sCDI）. The performance characteristics of sCDI included： brake power, specific fuel consumption, brake thermal efficiency and exhaust emissions （carbon dioxide, CO2, carbon monoxide CO, and hydrocarbon HC）. The findings show that the inlet air temperature and cooling conditions have appreciable effect on the performance characteristics of the sCDI especially at low cooling rate. It can be concluded that the high cooling rate leads to the enhancement in the brake thermal efficiency, the b.s.f.c, and the emitted COz, CO, and HC. On the other hand the high cooling rate leads to the decrease in the volumetric efficiency. so, a compromising between the inlet air temperature and the cooling rate should be recommended for the engine best performance.

关键词： Diesel engine inlet conditions performance test single cylinder.

Phosphogypsum Utilization Part Ⅲ:as Adhesive Filler and Composite materials

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Journal of materials science & Technology 2000年第4期16卷 439-444页

作者： A.A.Hanna, Y.m.Abu-Ayana and s.m.ahmed (National Research Centre, Dokki, Cairo, Egypt)

The aim of this work is to make use of phosphogypsum (PG) waste material, which is produced in phosphoric acid and phosphate fertilizer manufactures. A number of wood adhesive formulations based on polyvinyl acetate (PVAc) polymer and phosphogypsum as a filler have been prepared. using different percentages of phosphogypsum, ranging between 5-20 wt pct. The prepared formulations were tested for adhesion strength and compared with both natural and pure gypsum fillers. The results indicate that PG improves the adhesion strength when 5 wt pct added, and that may be due to filling the porous surface of wood with the fine particles of PG, as well as coating the particles of the filler (PG) with PVAc units. Also, a number of formulations based on urea-formaldehyde polymer have been prepared using phosphogypsum as an active filler in the ratio of 40-75 wt pct to prepare composite materials used for some decoration purposes and construction. mechanical, physical, and thermal properties of these formulations were studied. Also, the activation energy was calculated. The results indicate that PG without acid hardener can be used for preparation of composite materials based on urea-formaldehyde between 40-63.64 wt pct for construction purposes in the humid atmosphere, while between 63.64-75 wt pct for decoration purposes. The improvement of the physical, mechanical and thermal properties of the composite material may be attributed to the simultaneous hydration hardening action of phosphogypsum and the presence of 0.8% P_2O_5. These effects act as an active hardener for urea-formaldehyde resin and accelerate the cross-linking and network formation reinforced by the fine dusty inorganic particles of PG. The advantage of this method is to prepare composite material gypsum-urea-formaldehyde, which achieves the utilization of large amount of PG, reducing the price of the main product phosphate, minimizing the pollution and producing new materials which possess high thermal resistanc

关键词： than PG PVAc Phosphogypsum Utilization Part

Phosphogypsum:Part Ⅰ:mineralogical,Thermogravimetric,Chemical and Infrared Characterization

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Journal of materials science & Technology 1999年第5期15卷 431-434页

作者： A.A.Hanna A.I.m.Akarish and s.m.ahmed(National Research Centre, Dokki, P-O-12311, Cairo, Egypt) To whom correspondence should be addressed

Phosphogypsum (PG) derived from the dissolution of phosphate ore in H2sO4 has been characterized by using chemical and thermogravimetric analyses, X-ray difFraction and infrared spectrum to give an idea about the future utifization of this waste material. The PG under the investigation was free from the radioactive elements and Cd and contained about 141 × 10-6 rare earth elements in total, which favours the utilization of this material. PG was formed mainIy of gypsum, little anhydrite and quartz and rare kaolinite. It exhibited two large endothermic peaks corresponding to the dehydration of the sample and a small one which may be attributed to the Iiberation of the residual water that may be found in the soluble anhydrite. Also, an exothermic peak was observed which may be related to the transformation of soluble (γ-anhydrite) to insoluble β-anhydrite. PG exhibited the same absorption bands as that observed for chemical CasO4.2H2O and natural gypsum samples besides the appearance of a weak band at 840 cm-1 which characterizes the vibration of H2PO4- group

关键词： III mineralogical,Thermogravimetric,Chemical and Infrared Characterization Phosphogypsum IV Nature

Vascular endothelial growth factor:a double-edged sword in the development of white matter lesions

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Neural Regeneration Research 2025年第1期20卷 191-192页

作者： Narek manukjan Daniel Fulton Zubair ahmed Wmatthijs Blankesteijn sébastien Foulquier Department of Pharmacology and Toxicology Maastricht UniversityMaastrichtThe Netherlands CARIm-school for Cardiovascular Diseases Maastricht UniversityMaastrichtThe Netherlands Neuroscience and Ophthalmology Institute of Inflammation and AgeingUniversity of BirminghamEdgbastonBirminghamUK Centre for Trauma sciences Research University of BirminghamEdgbastonBirminghamUK mHeNs-school for mental Health and Neuroscience Maastricht UniversityMaastrichtThe Netherlands Department of Neurology Maastricht University Medical CenterMaastrichtThe Netherlands

As the population ages,the burden of age-related diseases becomes ***,over 55 million people suffer from dementia worldwide,with Alzheimer’s disease being the most common ***,it is becoming clearer that underlying vascular pathology such as cerebral small vessel disease(csVD)may be a more detrimental cause for dementia(Cuadrado-Godia et al.,2018).It is estimated that 10%-30%of the elderly population and 35%-90%of all dementia patients exhibit signs of *** term csVD refers to pathology affecting the small vessels of the brain,which can lead to lacunar cerebral infarcts,enlarged perivascular spaces,and cortical hemorrhages(Cuadrado-Godia et al.,2018).CsVD is often associated with cognitive decline,gait problems,and dementia(Cuadrado-Godia et al.,2018).

关键词： pathology becoming white

Phosphogypsum Utilization Part Ⅱ: Preparation of Ammonium sulphate

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Journal of materials science & Technology 1999年第6期15卷 571-574页

作者： A.A.Hanna and s.m.ahmed (Inorg. Chem. Dept., National Research Centre, Dokki, Cairo, Egypt)[ manuscript received

The aim of this work was to describe the conversion of raw phosphogypsum, issued from the manufacture of H3PO4 by dissolving the phosphate rock in H2sO4, into (NH4)2sO4 and *** thermal analysis technique was used to estimate the yield of conversion. (NH4)2CO3 or (NH4)2CO3 with excess NH4OH or (NH4)2CO3 with NH3 gas were used in the preparation of (NH4)2sO4 from phosphogypsum. The obtained samples were separated and tested by chemical and thermogravimetric analyses, infrared spectrum and X-ray diffraction and the optimum conditions of conversion were determined. The results indicated that the yield of conversion equals to 83.37 and 86.70% in case of using (NH4)2CO3 or (NH4)2CO3 with excess ammoniarespectively, while by using NH3 gas the percentage of conversion increased to 94.2% at a flow rate of 6 ml/min. Chemical analysis, infrared spectrum and X-ray diffraction patterns of the yield, (NH4)2sO4 were nearly similar to the standard sample.

关键词： NH Phosphogypsum Utilization Part Preparation of Ammonium sulphate

<i>gyrA</i>Gene mutation Conferring Phenotypic Cross-Resistance among Fluoroquinolones (Ofloxacin, Levofloxacin and Gatifloxacin) in multidrug Resistant <i>mycobacterium tuberculosis</i>strains Isolated from Pulmonary mDR-TB Patients in Bangladesh

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Journal of Tuberculosis Research 2018年第3期6卷 227-237页

作者： Tamanna Tasnim Fatema mohammad Alam s. m. Ali ahmed shirin Tarafder s. m. mostofa Kamal shamim Hossain Department of microbiology and Immunology Bangabandhu Sheikh Mujib Medical University (BSMMU) Dhaka Bangladesh National Tuberculosis Reference Laboratory (NTRL) National Institute of Diseases of the Chest and Hospital (NIDCH) Dhaka Bangladesh

Background and objectives: Fluoroquinolones (FLQs) are an essential component of multidrug resistant-tuberculosis (mDR-TB) treatment regimen but unfortunately the emergence of FLQ resistant mDR-TB cases is challenging the current mDR-TB treatment regimen. FLQ resistance is mainly caused by gyrA gene mutation and phenotypic cross-resistance may occur among the different FLQs. A limited number of data exists regarding the cross-resistance phenomenon among FLQs and it appears that resistance to the present class representative FLQ, ofloxacin (OFX), may or may not correlate with complete cross-resistance to other FLQs. so the study was designed to observe if gyrA gene mutations confer to the phenotypic cross-resistance among FLQs [OFX, Levofloxacin (LFX) and Gatifloxacin (GFX)] tested. methodology: sputum samples from 68 diagnosed pulmonary mDR-TB cases were collected. All samples were subjected to multiplex Real-time PCR for the detection of gyrA gene mutations and conventional culture on Lowenstein-Jensen (L-J) media followed by drug sensitivity testing (DsT) of culture isolates (mDR-TB strains) by indirect proportion method for the detection of phenotypic resistance pattern to OFX, LFX and GFX. Results: Out of the 68 mDR-TB sputum samples 13 (19.11%) had mDR-TB bacilli with mutations in the gyrA gene and 11(16.18%) of the mDR-TB culture isolates were found to have resistance to FLQs by DsT. The study observed that 11 mDR-TB samples with gyrA gene mutations showed complete phenotypic cross-resistance among OFX, LFX and GFX. Conclusion: This study found that mutation in the gyrA gene of the mDR-TB bacilli results in the complete cross-resistance among the FLQs (OFX, LFX and GFX) tested. It is therefore of utmost importance to carry out the base line resistance and cross-resistance tests for the individual FLQs prior to initiating the treatment of mDR-TB cases in Bangladesh for successful clinical outcomes.

关键词： multidrug Resistant-Tuberculosis (mDR-TB) gyrA Gene mutations Fluoroquinolones (FLQs) Cross-Resistance