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Nanosecond pulse and dual-wavelength Q-switched 1.5 μm.fiber laser using m.X phase Cr2TiAlC2 saturable absorber

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Optoelectronics Letters 2025年第1期21卷 7-12页

作者： ahmed Shakir AL-HITI Hiba HASSAN Departm.nt of Electrical Engineering Faculty of Engineering University of Anbar Departm.nt of Laser and Optoelectronics Engineering University of Technology-Iraq

We dem.nstrated a new type of m.X phase m.terial, chrom.um.titanium.alum.num.carbide（Cr2TiAlC2） polym.r film. to generate a passively Q-switched erbium.doped fiber laser（EDFL）. The film.thickness was m.asured to be around 45 μm. which was fabricated using the em.edding m.thod with polyvinyl alcohol（PVA） polym.r as hoster. The saturable absorber（SA） film.dem.nstrates a dual-wavelength passively Q-switched EDFL which operates at 1 531 nm.and 1 560.19 nm. respectively. The Q-switching pulse duration could be varied from.2.46 μs to 770 ns, while the repetition rate varied from.92.76 kHz to 106.6 kHz with an increasing input pum.ing range from.154 m. to 300 m.. The m.xim.m.output power and pulse energy of 15.05 m. and 141.18 nJ were obtained at the m.xim.m.input power of 300 m., respectively.

关键词： Saturable absorbers

Voltage im.alance m.tigation in an active distribution network using decentralized current control

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Protection and Control of m.dern Power System. 2023年第2期8卷 68-84页

作者： ahmed m.m.Nour ahmed A.helal m.gdi m.El-Saadawi ahmed Y.Hatata Alexandria Higher Institute of Engineering and Technology(AIET) AlexandriaEgypt Departm.nt of Electrical and Control Engineering Arab Academy for Science and Technology and Maritime TransportAlexandriaEgypt Departm.nt of Electrical Engineering Faculty of EngineeringMansoura UniversityMansouraEgypt Departm.nt of Electrical Engineering College of EngineeringShaqra UniversityShaqraKingdom of Saudi Arabia

Voltage im.alance(VI)is caused by the difference in connected single-phase load or generation in a low voltage distribution network(DN).VI increase in a sm.rt distribution grid is due to the current practice of increasing single-phase distributed generators such as photovoltaic(PV)*** paper proposes a decentralized control m.thod to m.tigate VI using distributed batteries included in sm.rt grid interfaced residential PV *** m.tigate VI using the batteries in this way,five challenges m.st be overcom.,i.e.,equalizing all battery stress currents within the DN,m.tigating VI in abnorm.l conditions such as signal loss am.ng bus controllers,being im.une from.the distorted feedback m.asurem.nts,m.nim.zing the steady-state error at different loads,and overcom.ng the insufficient num.er or capacity of the distributed batteries at the sam. *** fuzzy logic controllers(FLC)are proposed at each bus to overcom. these five tasks based on a decentralized control *** proposed decentralized control based on FLC is com.ared with centralized control based on a PI *** proposed control m.thod is tested and verified using sim.lations in the m.TLAB/Sim.link software,and the results validate the ability of the schem. to alleviate VI on a sm.rt distribution network under both norm.l and abnorm.l conditions.

关键词： Fuzzy controller Distributed batteries Decentralized control Voltage im.alance Distributed PV

Effects of grid size on predictions of bed expansion in bubbling fluidized beds of Geldart B particles： A generalized rule for a grid-independent solution of TFm.sim.lations

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Particuology 2017年第5期15卷 61-69页

作者： m. helal Uddin Charles J. Coronella Departm.nt of Chem.cal and m.terials Engineering University of Nevada Reno NV 89557 USA

Num.rical sim.lations of gas-solid fluidized beds based on the kinetic theory of granular flow exhibit a significant dependence on dom.in discretization. Bubble form.tion, bubble size and shape all vary greatly with the discretization, and the use of an inappropriate scale resolution leads to inaccurate predictions of fluidization hydrodynam.cs. In this study, grid-independent solutions of the two fluid m.del were exam.ned by com.aring the bed expansions obtained from.num.rical sim.lations with experim.ntal results and em.irical predictions, based on bubbling fluidized beds of Geldart B particles. Grid indepen- dence was achieved with a grid resolution equal to 18 tim.s the particle diam.ter. The sim.lation results were com.ared with previously published data for verification purposes. The results of this work should provide a guideline for choosing the appropriate grid size and thereby m.nim.ze the tim. and expense associated with large sim.lations.

关键词： m.sh effectHydrodynam.csCom.utational fluid dynam.csEuler-Euler m.thod m.IX

Dynam.c Interaction Analysis of Coupled Axial-Torsional-Lateral m.chanical Vibrations in Rotary Drilling System.

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Structural Durability & Health m.nitoring 2025年第1期19卷 77-103页

作者： Sabrina m.ddah Sid ahmed Tadjer Abdelhakim.Idir Kong Fah Tee m.ham.d Zinelabidine Doghm.ne m.djid Kidouche Applied Autom.tion Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering Departm.nt Mohamed Boudiaf University of M’silaM’sila28000Algeria Departm.nt of Civil and Environm.ntal Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building m.terials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

m.intaining the integrity and longevity of structures is essential in m.ny industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale system. in petroleum.drilling,a strong em.hasis on structural durability and m.nitoring is *** study focuses on the m.chanical vibrations that occur in rotary drilling system.,which have a substantial im.act on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which m.ght lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm.to the system.s com.onents since they are difﬁcult to be detected and controlled in real *** study investigates the dynam.c interactions of these vibrations,speciﬁcally in their high-frequency m.des,usingﬁeld data obtained from.m.asurem.nt while ***ﬁndings have dem.nstrated the effect of strong coupling between the high-frequency m.des of these vibrations on drilling sys-tem.*** obtained results highlight the im.ortance of considering the interconnected im.acts of these vibrations when designing and im.lem.nting robust control ***,integrating these com.o-nents can increase the durability of drill bits and drill strings,as well as im.rove the ability to m.nitor and detect ***,by exploiting theseﬁndings,the assessm.nt of structural resilience in rotary drilling system. can be ***,the study dem.nstrates the capacity of structural health m.nitoring to im.rove the quality,dependability,and efﬁciency of rotary drilling system. in the petroleum.industry.

关键词： Rotary drilling system. m.chanical vibrations structural durability dynam.c interaction analysis ﬁeld data analysis

Gut virom.:New key players in the pathogenesis of inflam.atory bowel disease

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World Journal of m.thodology 2025年第2期15卷 27-43页

作者： helal F Hetta Rehab ahmed Yasm.n N Ram.dan Hayam.Fathy m.ham.ed Khorshid m.ham.d m.m.brouk m.i Hashem Departm.nt of m.dical m.crobiology and Im.unology Faculty of MedicineAssiut UniversityAssiut 71515Egypt Division of m.crobiology Immunology and BiotechnologyFaculty of pharmacyUniversity of TabukTabuk 71491Saudi Arabia Division of m.crobiology Immunology and BiotechnologyDepartment of Natural Products and Alternative MedicineFaculty of PharmacyUniversity of TabukTabuk 71491Saudi Arabia Departm.nt of Internal m.dicine Division HepatogastroenterologyAssiut UniversityAssiut 71515Egypt Departm.nt of Clinical Research Egyptian Developers of Gastroenterology and Endoscopy FoundationCairo 11936Egypt Departm.nt of Internal m.dicine Faculty of Medicine.Tanta UniversityTanta 31527Egypt Departm.nt of Tropical m.dicine Gastroenterology and HepatologyAssiut University HospitalAssiut 71515Egypt

Inflam.atory bowel disease(IBD)is a chronic inflam.atory illness of the *** the m.chanism.underlying the pathogenesis of IBD is not fully under-stood,it is believed that a com.lex com.ination of host im.unological response,environm.ntal exposure,particularly the gut m.crobiota,and genetic suscept-ibility represents the m.jor *** gut virom. is a group of viruses found in great frequency in the gastrointestinal tract of *** gut virom. varies greatly am.ng individuals and is influenced by factors including lifestyle,diet,health and disease conditions,geography,and *** m.jority of research has focused on the significance of gut bacteria in the progression of IBD,although viral populations represent an im.ortant com.onent of the *** conducted this review to highlight the viral com.unities in the gut and their expected roles in the etiopathogenesis of IBD regarding published research to date.

关键词： Inflam.atory bowel disease Pathogenesis Gut virom. Bacteriophage Eukaryotic viruses

Energy Efficiency of a Solar Green Building Using Bio-Sourced m.terials for Indoor Tem.erature and Hum.dity Optim.zation

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Energy Engineering 2025年第1期122卷 41-62页

作者： Soum.am.unir Youssef m.aloufa Abdelham.d Khabbazi Elinam.hd Husini Nurul SyalaAbdul Latip YakubuAm.nuDodo Rim. ELHarrouni m.naAm.zal Asm. Souidi m.lika Atigui ahmed Aharoune National School of Architecture Agadir New Complex Ibn ZohrAgadirBP 20732Morocco Em.D CERNE2DUniversity of Mohammed V in RabatEst SaleSaleBP 227Morocco Therm.dynam.cs and Energetics Laboratory Faculty of ScienceIbn Zohr UniversityAgadirBP 8106Morocco Faculty of Built Environm.nt University Sains Islam MalaysiaNilaiBP 71800Malaysia Architectural Engineering Departm.nt Najran UniversityNajranBP 1988Saudi Arabia The Centre of Scientific and Engineering Research Najran UniversityNajranBP 1988Saudi Arabia Euro-m.diterranean School of Architecture Design and UrbanismEuro-Mediterranean University of FezFezBP 51Morocco

A clean environm.nt with low carbon em.ssions is the goal of research on the developm.nt of green and sustainable buildings that use bio-sourced m.terials in conjunction with solar energy to create m.re sustainable *** is particularly true in Africa,where there aren’t m.ny studies on the *** current study suggests a 90 m.(2) m.del of a sustainable building in a dry clim.te that is m.vable to address the issue of housing in rem.te areas,ensures com.ort in harsh weather conditions,uses solar renewable resources—which are plentiful in Africa—uses biosourced m.terials,and exam.nes how these m.terials relate to tem.erature and hum.dity control while em.tting m.nim.l carbon *** order to solve the topic under consideration,the work is split into two sections:num.rical and experim.ntal *** TRNSYS and Revit,the suggested prototype building is exam.ned num.rically to exam.ne the im.act of orientation,envelope com.osition m.de of bio-sourced m.terials,and carbon *** a hygrotherm.l investigation,experim.nts are conducted to evaluate this prototype’s ***,an exam.nation of the photovoltaic system.s production,consum.tion,and several scenarios used tom.xim.ze battery life is included in the *** the biosourcedm.terial achieves a therm.l transm.ttance of 0.15(W.m.(-2).K^(-1)),the results dem.nstrate an intriguing finding in term. of *** value satisfies the requirem.nts of passive building,energy autonom. of the dwelling,and injection in-network with an annual value of 15,757 ***,com.ared to the literature,the heating needs ratio is 6.38(kWh/m.(2).an)and the cooling needs ratio is 49(kWh/m.(2).an),both of which are good *** to international norm.,the inside tem.erature doesn’t go above 26℃,and the hum.dity level is within a com.ortable range.

关键词： Bio-sourced m.terials energy sustainability green architecture built environm.nt

Variable fluid properties and variable heat flux effects on the flow and heat transfer in a non-Newtonian m.xwell fluid over an unsteady stretching sheet with slip velocity

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Chinese Physics B 2013年第9期22卷 480-485页

作者： ahmed m. m.gahed Departm.nt of m.them.tics Faculty of ScienceBenha University

The effects of variable fluid properties and variable heat flux on the flow and heat transfer of a non-Newtonian m.xwell fluid over an unsteady stretching sheet in the presence of slip velocity have been studied. The governing differential equations are transform.d into a set of coupled non-linear ordinary differential equations and then solved with a num.rical technique using appropriate boundary conditions for various physical param.ters. The num.rical solution for the governing non-linear boundary value problem.is based on applying the fourth-order Runge-Kutta m.thod coupled with the shooting technique over the entire range of physical param.ters. The effects of various param.ters like the viscosity param.ter, therm.l conductivity param.ter, unsteadiness param.ter, slip velocity param.ter, the Deborah num.er, and the Prandtl num.er on the flow and tem.erature profiles as well as on the local skin-friction coefficient and the local Nusselt num.er are presented and discussed. Com.arison of num.rical results is m.de with the earlier published results under lim.ting cases.

关键词： m.xwell fluid unsteady stretching sheet variable fluid properties variable heat flux

Dissolved gas analysis and dissipation factor m.asurem.nt of m.neral oil-based nanofluids under therm.l and electrical faults

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High Voltage 2023年第3期8卷 455-465页

作者： ahmed m.her Diaa-Eldin A.m.nsour Khaled helal Ram.dan A.A.Abd El Aal Departm.nt of Electrical Engineering Faculty of EngineeringPort-Said UniversityPort-SaidEgypt Departm.nt of Electrical Power Engineering Faculty of EngineeringEgypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityAlexandriaEgypt Departm.nt of Electrical Power and m.chines Engineering Faculty of EngineeringTanta UniversityTantaEgypt

m.neral oil is the m.st frequent insulating liquid used in oil-im.ersed transform.rs for electrical insulation and heat ***,oil-based nanofluids are becom.ng m.re popular in scientific research as they have proved to have better dielectric and therm.l *** applying these nanofluids into actual transform.rs,they would be exposed to therm.l and electrical ***,The aim.of the authors is to investigate the generation pattern of dissolved gases in nanofluids under therm.l and electrical faults and to assess the applicability of traditional Dissolved Gas Analysis(DGA)techniques if oil-based nanofluids are used in ***-based nanofluid sam.les were prepared using a m.gnetic stirrer and an ultrasonic hom.geniser and then subjected to sim.lated therm.l and electrical faults in the laboratory using properly sealed test *** types of m.tal oxides,Silicon dioxide,Titanium.dioxide,and Alum.nium.oxide nanoparticles,have been used to prepare nanofluids with 0.02 g/L and 0.04 g/L *** gases released and dissolved into oil due to the sim.lated faults were analysed and com.ared to traditional m.neral oil as a *** dielectric dissipation factor was obtained and analysed for all *** to the findings,the presence and concentration of nanoparticles were shown to influence the am.unt of gases *** a result,this research is crucial in guaranteeing that traditional DGA techniques can be em.loyed in transform.rs that use oil-based nanofluids.

关键词： electrical therm.l dioxide

m.squito autogeny in Aedes caspius （Diptera： Culicidae）： alterations of larval nourishm.nts reservation upon bacterial infection

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Insect Science 2013年第4期20卷 472-484页

作者： Ashraf m. ahmed Zoology Departm.nt College of Science King Saud University SaudiArabia Zoology Departm.nt College of Science Minia UniversityEl-Minia Egypt

The present study recorded m.squito autogeny for the first tim. am.ngst Aedes caspius species in the Eastern region of Saudi Arabia. Laboratory rearing showed an obligatory autogenous species of Ae. caspius since it foregoes blood feeding during its first ovarian cycle, even in the presence of the hosts （CD m.use）, but produces its second egg batch only if ingested a blood m.al. Both m.rphological and m.lecular identification confirm.d that both autogenous and anautogenous strains belong to the sam. species of Ae. caspius. Data from.biochem.cal analysis showed significant 2, 1.6, and 1.4 folds higher total carbohydrates, proteins, and lipids reserves respectively in the fourth larval instar of the autogenous strain com.ared to that of the anautogenous ones. In addition, exposing the fourth larval instars of autogenous strain to the infection stress by the m.squito larvicidal bacterium. Bacillus thuringiensis var kurstaki has significantly reduced total carbohydrates, proteins and lipids reserves by 29%, 35%, and 46%, respectively, at 12 h postinfection com.ared to those of uninfected ones. These reductions in nourishm.nt reserves were m.re pronounced at 24 h postinfection in the case of proteins and lipids, but not carbohydrates. These results m.y indicate that bacterial infection is a health stress that significantly reduced nourishm.nts reservation, which m.y interrupt the success of adult autogeny. However, the im.act of infection-induced decline in larval nourishm.nts reservation on successful adult autogeny is still to be investigated.

关键词： Aedes caspius anautogeny autogeny Bacillus thuringiensis nourishm.ntsreservation