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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

m.tigation of the blast load effects on a building structure using newly com.osite structural configurations

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Defence Technology（防务技术） 2021年第1期17卷 75-84页

作者： ahmed K.taha m.S.Zahran Zhengguo Gao School of Transportation Science and Engineering Beihang University(Beijing University of Aeronautics and Astronautics)Beijing100191PR China Departm.nt of Civil Engineering Military Technical CollegeEgypt

In this study,a nonlinear three-dim.nsional hydrocode num.rical sim.lation was carried out using AUTODYN-3D to investigate the effect of blasting of a high explosive m.terial(TNT)against several configurations of the com.osite *** num.rical m.dels were carried out to study the effect of varying the thickness of the walls and the effect of adding an air layer or alum.num.foam.layer inside two layers of concrete in m.tigating the effect of blast waves on the structure *** results showed that increasing the thickness of walls has a good effect on m.tigating the effect of blast *** a layer of air was added,the effect of blast waves was exaggerated,while when a layer of alum.num.foam.was added the blast wave effects were m.tigated with a reasonable percentage.

关键词： Concrete structures Blast waves Num.rical sim.lation TNT

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

Finite elem.nt m.deling assum.tions im.act on seism.c response dem.nds of m.F-buildings

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Earthquake Engineering and Engineering Vibration 2018年第4期17卷 821-834页

作者： Shehata E Abdel Raheem.ahmed K Abdel Zaher ahmed m. taha Civil Engineering Departm.nt Engineering College Taibah University Civil Engineering Departm.nt Faculty of Engineering Assiut University

Recent seism.c events have raised concerns over the safety and vulnerability of reinforced concrete m.m.nt resisting fram. ＂RC-m.F＂ buildings. The seism.c response of such buildings is greatly dependent on the com.utational tools used and the inherent assum.tions in the m.delling process. Thus, it is essential to investigate the sensitivity of the response dem.nds to the corresponding m.delling assum.tion. m.ny param.ters and assum.tions are justified to generate effective structural finite elem.nt（FE） m.dels of buildings to sim.late lateral behaviour and evaluate seism.c design dem.nds. As such, the present study focuses on the developm.nt of reliable FE m.dels with various levels of refinem.nt. The effects of the FE m.delling assum.tions on the seism.c response dem.nds on the design of buildings are investigated. the predictive ability of a FE m.del is tied to the accuracy of num.rical analysis; a num.rical analysis is perform.d for a series of sym.etric buildings in active seism.c zones. The results of the seism.c response dem.nds are presented in a com.arative form.t to confirm.drift and strength lim.ts requirem.nts. A proposed m.del is form.lated based on a sim.lified m.deling approach, where the m.st refined m.del is used to calibrate the sim.lified m.del.

关键词： RC-m.F buildings design codes provisions seism.c design finite elem.nt m.deling m.deling assum.tions response dem.nds

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

Preparation and application of am.no functionalized m.soporous nanofiber m.m.rane via electrospinning for adsorption of Cr^(3+) from.aqueous solution

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Journal of Environm.ntal Sciences 2012年第4期24卷 610-616页

作者： ahmed A.taha Junlian Qiao Fengting Li Bingru Zhang College of Environm.ntal Science and Engineering UNEP Tongji Institute of Environment for Sustainable DevelopmentState Key Laboratory of Pollution Control and Resource ReuseTongji University

Novel am.no （-NH2） functionalized m.soporous polyvinyl pyrrolidone （PVP）/SiO2 com.osite nanofiber m.m.ranes were fabricated by a one-step electrospinning m.thod using poly （vinyl alcohol） and tetraethyl orthosilicate （TEOS） m.xed with cationic surfactant, cety｜trim.thyl am.onium.brom.de （CTAB） as the structure directing agent. Ureidopropyltriethoxysilane was used for functionalization of the internal pore surfaces. The m.m.ranes were characterized by scanning electron m.croscopy （SEm., high-resolution transm.ssion electron m.croscopy （HRTEm. im.ges, X-ray diffraction （XRD）, Fourier-transform.infrared spectroscopy （FT-IR）, elem.nt analyzer and Nz adsorption-desorption isotherm., The nanofiber diam.ters, average pore diam.ters and surface areas were 100-700 nm. 2.86 nm.and 873,62 m./g, respectively. These m.soporous m.m.ranes functionalized with -NH2 groups exhibited very high adsorptions properties based on the adsorption of Cr3＋ from.an aqueous solution. Equilibrium.adsorption was achieved after approxim.tely 20 rain and m.re than 97% of chronium.ions in the solution were rem.ved. The m.m.rane could be regenerated through acidification.

关键词： m.soporous electrospinning nanofiber am.no groups adsorption

m.dified particle swarm.optim.zation for optim.m.design of spread footing and retaining wall

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第6期12卷 415-427页

作者： m.ham.ad KHAJEHZADEH m.hd Raihan taha ahmed EL-SHAFIE m.hdiyeh ESLAm. Departm.nt of Civil Engineering Anar BranchIslamic Azad University Departm.nt of Civil and Structural Engineering University Kebangsaan Malaysia Departm.nt of Electrical Engineering Anar BranchIslamic Azad University

This paper deals with the econom.cally optim.zed design and sensitivity of two of the m.st widely used system. in geotechnical engineering: spread footing and retaining wall. Several recent advanced optim.zation m.thods have been developed, but very few of these m.thods have been applied to geotechnical problem.. The current research develops a m.dified particle swarm.optim.zation (m.SO) approach to obtain the optim.m.design of spread footing and retaining wall. The algorithm.handles the problem.specific constraints using a penalty function approach. The optim.zation procedure controls all geotechnical and structural design constraints while reducing the overall cost of the structures. To verify the effectiveness and robustness of the proposed algorithm. three case studies of spread footing and retaining wall are illustrated. Com.arison of the results of the present m.thod, standard PSO, and other selected m.thods em.loyed in previous studies shows the reliability and accuracy of the algorithm. m.reover, the param.tric perform.nce is investigated in order to exam.ne the effect of relevant variables on the optim.m.design of the footing and the retaining structure utilizing the proposed m.thod.

关键词： Particle swarm.optim.zation (PSO) Spread footing Retaining wall Sensitivity analysis

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