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Nanosecond pulse and dual-wavelength Q-switched 1.5 μm fiber laser using mAX 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 Department of Electrical Engineering Faculty of Engineering University of Anbar Department of Laser and Optoelectronics Engineering University of Technology-Iraq

We demonstrated a new type of mAX phase material, chromium titanium.aluminum carbide（Cr2TialC2） polymer film, to generate a passively Q-switched erbium-doped fiber laser（EDFL）. The film thickness was measured to be around 45 μm, which was fabricated using the embedding method with polyvinyl alcohol（PVA） polymer as hoster. The saturable absorber（SA） film demonstrates 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 pumping range from 154 mW to 300 mW. The maximum output power and pulse energy of 15.05 mW and 141.18 nJ were obtained at the maximum input power of 300 mW, respectively.

关键词： Saturable absorbers

Temperature Uniformity,Correlations and the Flow Field in Swirling Impinging Jets

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Journal of Thermal Science 2023年第2期32卷 662-679页

作者： Zahir U.ahmed Yasir m.al-ABDELI Department of mechanical Engineering Khulna University of Engineering&TechnologyKhulna 9203Bangladesh School of Engineering Edith Cowan UniversityJoondalupWA 6027Australia

Infrared thermography,velocity and impingement pressure measurements alongside numerical modelling are used in this study to resolve(heated)surface temperature distributions of turbulent swirling impinging jets for two Reynolds numbers(Re=11600 and 24600).Whilst building upon earlier discoveries for this same geometry,this paper provides three new contributions:(1)identifying the role of impingement distance(H/D)as a deciding factor in the trade-off between more efficient heat transfer(at high swirl numbers)and achieving better substrate temperature uniformity(lower gradients),(2)developing correlations to predict Nusselt number for swirling and non-swirling cooling jets,and(3)predicting the underlying mixing field in these jets and its interplay with the thermal distributions *** indicate substrate temperature uniformity varies based on H/D and swirl intensity(S)with a significant level of thermal non-uniformity occurring in near-field impingement(H/D=1)at stronger swirl(S=0.59 and 0.74).Four correlations describing the effects of S,Re,and H on the average heat transfer and stagnation heat transfer are developed and yield accuracies of 8%and 12%,*** recirculation near the impingement surface is predicted at H/D=1 for stronger swirl jets which disappears at other substrate *** peak wall shear stress reduces and the flow impingement becomes radially wider at higher H/D and *** turbulence or eddy viscosity regions for non-swirling jets(S=0)are predicted in the shear layer and entrainment regions at H/D=1,but such turbulence is confined to the impingement and wall jet regions for strongly swirling flows.

关键词： Temperature uniformity Nusselt number IR imaging CTA RANS

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Hydromechanical behavior of unsaturated expansive clay under repetitive loading

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Journal of Rock mechanics and Geotechnical Engineering 2021年第5期13卷 1136-1146页

作者： ahmed m.al-mahbashi mosleh A.al-Shamrani mohammad F.Abbas Bugshan Research Chair in Expansive Soils Department of Civil EngineeringKing Saud UniversityRiyadh11421Saudi Arabia Civil Engineering Department Prince Sattam bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia Soil mechanics and Geotechnical Engineering Research Institute Housing and Building National Research Center(HBRC)Giza11511Egypt

Compacted layers of expansive soils are used in different engineering projects,such as subgrades,engineered clay barriers,and buffers for radioactive waste *** layers are exposed to a variety of stresses and wetting conditions during field *** between hydraulic and mechanical repeated loading provides insight understanding to the induced progressive deformation of expansive *** study was conducted to investigate the hydromechanical behavior of unsaturated compacted expansive clay under repeated loadingeunloading(RLU)*** series of onedimensional(1D)oedometer tests were conducted under controlled matric suction up to 1500 kPa using the axis translation technique(Fredlund soil-water characteristic curve device,SWC-150).The first test series was carried out at different levels of controlled matric suction for non-repeated loading eunloading(NRLU)*** cycles were applied in the second test series at different repetitivestress levels and under different levels of matric *** results indicated increasing axial wetting strainε_(a)(s),axial swell pressure ss(s),compression index C_(c)(s),and swell index C_(s)(s)with suction *** estimated loadecollapse(LC)curves obtained from NRLU series(LCN)and RLU series(LCR)indicated increasing yield stress sy(s)with increasing *** is attributed to the developed apparent cohesion between soil particles,which in turn rigidifies the material *** repetitive loading induced a notable reduction of compression index C_(c)(s)at the same level of suction,whereas swell index C_(s)(s)seems to be independent of repetitive ***,repetitive loading exceeding initial yield stresses results in plastic hardening and,hence,enlargement of yield stress locus(*** curve).

关键词： Expansive clay Repetitive loading Suction Hydromechanical behavior Loadecollapse curve

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maize response to elevated plant density combined with lowered N-fertilizer rate is genotype-dependent

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The Crop Journal 2015年第2期3卷 96-109页

作者： ahmed medhat m.al-Naggar Reda A.Shabana mohamed m.m.Atta Tarek H.al-Khalil Agronomy Department Faculty of Agriculture Cairo University

Increasing plant density and improving N fertilizer rate along with the use of high density-tolerant genotypes would lead to maximizing maize(Zea mays L.) grain productivity per unit land area. The objective of this investigation was to match the functions of optimum plant density and adequate nitrogen fertilizer application to produce the highest possible yields per unit area with the greatest maize genotype efficiency. Six maize inbred lines differing in tolerance to low N and high density(D) [three tolerant(T); L-17, L-18, L-53,and three sensitive(S); L-29, L-54, L-55] were chosen for diallel crosses. Parents and crosses were evaluated in the 2012 and 2013 seasons under three plant densities: low(47,600),medium(71,400), and high(95,200) plants ha-1and three N fertilization rates: low(no N addition), medium(285 kg N ha-1) and high(570 kg N ha-1). The T × T crosses were superior to the S × S and T × S crosses under the low N–high D environment in most studied traits across seasons. The relationships between the nine environments and grain yield per hectare(GYPH) showed near-linear regression functions for inbreds L54, L29, and L55 and hybrids L18 × L53 and L18 × L55 with the highest GYPH at a density of47,600 plants ha-1and N rate of 570 kg N ha-1and a curvilinear relationship for inbreds L17, L18, and L53 and the rest of the hybrids with the highest GYPH at a density of95,200 plants ha-1combined with an N rate of 570 kg N ha-1. Cross L17 × L54 gave the highest grain yield in this study under both high N–high-D(19.9 t ha-1) and medium N–high-D environments(17.6 t ha-1).

关键词： Quadratic regression Appropriate N rate High-density tolerant maize Unit area productivity

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Control of hybrid DC/AC microgrid system employing fuel cell and solar photovoltaic sources using grey wolf optimization

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Clean Energy 2022年第4期6卷 659-670页

作者： ahmed m.al-Antaki T.V.Golubchik mushtaq A.al-Furaiji H.J.mohammed moscow Automobile and Road Construction State Technical University(mADI) Leningradsky Ave.64Moscow125319Russian Federation Bauman moscow State Technical University MoscowRussian Federation Faculty of Energy and Ecotechnology ITMO University49 Kronverksky prospectSt.Petersburg197101Russian Federation Department of mechanical Engineering College of EngineeringUniversity of MisanMisanAl-Amarah62001Iraq Institute of Energy Peter the Great St.Petersburg Polytechnic UniversitySaint Petersburg 195251Russian Federation

The outcome of this study is to improve and enhance the power quality of the hybrid DC/AC microgrid(mG).The photovoltaic(PV)system and the proton exchange membrane fuel cell(PEmFC)are used as renewable energy sources to deliver the optimum active power to the utility *** mG system based on the PV system,PEmFC and voltage source inverter is modelled ***,the maximum power point tracking(mPPT)-based grey wolf optimization(GWO)is used to increase the PV module efficiency and enhance ***,to improve the PEmFC performance,a digital proportional-integral controller is used to control the PEmFC *** proposed inverter is controlled using synchronous reference frame theory,called the direct-quadrature(dq)control ***,the performance of the proposed mG system is tested using mATLAB®for various weather and loading condi*** the simulation results,the proposed mG system can deliver and absorb an active power based on the PV and fuel cell *** a result,the hybrid DC/AC mG is enhanced in terms of stabilization of the DC-bus ***,the power quality of the mG is improved using GWO optimization based on ***,good results are achieved using GWO in terms of the total harmonic distortion of the output current of 2.3%and higher efficiency of 98.9%.

关键词： DC/AC inverter optimization

Distinctive clinical and laboratory features of COVID-19 and H1N1 influenza infections among hospitalized pediatric patients

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World Journal of Pediatrics 2021年第3期17卷 272-279页

作者： ali alsuheel Asseri Ayed A.Shati Saleh m.al-Qahtani Ibrahim A.alzaydani ahmed A.al-Jarie mohammed J.alaliani Abdelwahid Saeed ali Department of Child Health College of MedicineKing Khalid UniversityAbhaSaudi Arabia Department of Pediatrics Abha Maternity and Children HospitalAbhaSaudi Arabia General Directorate of Health Affairs Infection Prevention and Control AdministrationAseer RegionMinistry of HealthAbhaSaudi Arabia Department of microbiology and Clinical Parasitology College of MedicineKing Khalid UniversityAbhaSaudi Arabia

Background It had been documented in many studies that pediatric coronavirus disease 2019(COVID-19)is characterized by low infectivity rates,low mortalities,and benign disease *** the other hand,influenza type A viruses are recognized to cause severe and fatal infections in children populations *** study is aimed to compare the clinical and laboratory characteristics of COVID-19 and H1N1 influenza *** A retrospective study comprising 107 children hospitalized at Abha maternity and Children Hospital,Southern region of Saudi Arabia,with laboratory-confirmed COVID-19 and H1N1 influenza infections was carried out.A complete follow-up for all patients from the hospital admission until discharge or death was *** clinical data and laboratory parameters for these patients were collected from the medical records of the *** Out of the total enrolled patients,73(68.2%)were diagnosed with COVID-19,and 34(31.8%)were diagnosed with H1N1 *** median age is 12 months for COVID-19 patients and 36 months for influenza patients.A relatively higher number of patients with influenza had a fever and respiratory symptoms than COVID-19 *** contrast,gastrointestinal symptoms were observed in a higher number of COVID-19 patients than in influenza patients.A statistically significant increase in white cell counts is noted in COVID-19 but not in influenza patients(Pmean period of duration of hospitalization between COVID-19 and influenza ***,the total intensive care unit length of stay was longer for influenza compared to COVID-19 *** A considerable number of children infected with COVID-19 and H1N1 influenza were noted and reported in this *** were no significant variations in the severity of the symptomatology and laboratory findings between the two groups of *** differences between these patients in some hospitalization facto

关键词： Children Coronavirus disease 2019 H1N1 influenza.Laboratory indices Symptoms

Effectiveness of in-office blood pressure measurement by eye care practitioners in early detection and management of hypertension

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International Journal of Ophthalmology(English edition) 2015年第3期8卷 612-621页

作者： Saud A.al Anazi Uchechukwu L.Osuagwu Turki m.al mubrad Hany K.ahmed Kelechi C.Ogbuehi Department of Optometry & Vision Science King Saud University Institute of Health and Biomedical Innovation Department of Optometry & Vision Sciences Faculty of HealthQueensland University of Technology al-Ghad International College of Applied medical Sciences Department of medicine Dunedin School of MedicineUniversity of Otago

AIm: To investigate the number of hypertensive patients, the optometrist is able to identify by routinely taking blood pressure(BP) measurements for patients in "at-risk" groups, and to sample patients’ opinions regarding in-office BP measurement. many of the optometrists in Saudi Arabia practice in optical *** stores are wide spread, easily accessible and seldom need appointments. The expanding role of the optometrist as a primary health care provider(PHCP) and the increasing global prevalence of hypertension,highlight the need for an integrated approach towards detecting and monitoring ***: Automated BP measurements were made twice(during the same session) at five selected optometry practices using a validated BP monitor(Omron m6) to assess the number of patients with high BP(HBP)- in at-risk groups-visiting the eye clinic routinely. Prior to data collection, practitioners underwent a two-day training workshop by a cardiologist on hypertension and how to obtain accurate BP readings. A protocol for BP measurement was distributed and retained in all participating clinics. The general,,.,attitude towards cardiovascular health of 480 patients aged 37.2(±12.4)y and their opinion towards in-office BP measurement was assessed using a self-administered ***: A response rate of 83.6% was obtained for the survey. Ninety-three of the 443 patients(21.0%)tested for BP in this study had HBP. Of these,(62subjects) 67.7% were unaware of their HBP status. Thirty of the 105 subjects(28.6%) who had previously been diagnosed with HBP, still had HBP at the time of this study, and only 22(73.3%) of these patients were on medication. also, only 25% of the diagnosed hypertensive patients owned a BP ***: Taking BP measurements in optometry practices, we were able to identify one previously undiagnosed patient with HBP for every 8 adults *** also identified 30 of 105 previously diagnosed patients whose BP was poorly controlled

关键词： hypertension blood pressure optometrist public health high blood pressure

Fission of Weakly Prolate 119Sn and Weakly Oblate ^(209)Bi Nuclei Induced by 500 and 672 meV Negative Pions

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Chinese Physics Letters 2011年第9期28卷 88-91页

作者： mukhtar ahmed Rana Gul Sher Shahid manzoor m.I.Shahzad Physics Division Pakistan Institute of Nuclear Science and Technology(PINSTECH)P.O.NiloreIslamabadPakistan

Fission cross-sections of ^(119)Sn and ^(209)Bi induced by negative pions of two energies 500 and 672 meV were measured using a CR−39 nuclear track ***-detector stacks were exposed to pion beams at the Brookhaven National Laboratory(USA).measurement results are compared with the corresponding calculations using the computer code *** between measurements and calculations is fairly good for the ^(209)Bi target nuclei whereas it is poor for 119Sn at both investigated energies of 500 and 672 *** cross−section results of^( 119)Sn and ^(209)Bi are explained using the equilibrium properties of these nuclides including nuclear electric quadrupole moments which determine the shapes of nuclei.A logarithmic dependence of fission cross−section on Z^(2)/A is observed for the above−mentioned reactions and a critical limit of Z^(2)/A is identified with the value of 30 which divides the curve ofσf versus Z2/A into two regimes,one with weak dependence and the other with strong dependence.

关键词： Weakly mentioned limit

Design of machine Learning Based Smart Irrigation System for Precision Agriculture

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Computers, materials & Continua 2022年第7期72卷 109-124页

作者： Khalil Ibrahim mohammad Abuzanouneh Fahd N.al-Wesabi Amani Abdulrahman albraikan mesfer al Duhayyim m.al-Shabi Anwer mustafa Hilal manar ahmed Hamza Abu Sarwar Zamani K.muthulakshmi Department of Information Technology College of ComputerQassim UniversityAl-Bukairiyah52571Saudi Arabia Department of Computer Science King Khalid UniversityMuhayel Aseer62529Saudi Arabia&Faculty of Computer and ITSana’a UniversitySana’a61101Yemen Department of Computer Science College of Computer and Information SciencesPrincess Nourah Bint Abdulrahman UniversityRiyadh11564Saudi Arabia Department of Natural and Applied Sciences College of Community-AflajPrince Sattam bin Abdulaziz UniversityAl-Kharj16278Saudi Arabia Department of management Information System College of Business and AdministrativeTaibah UniversityMedina42353Saudi Arabia Department of Computer and Self Development Preparatory Year DeanshipPrince Sattam bin Abdulaziz UniversityAl-Kharj16278Saudi Arabia Department of Electronics and Communication Engineering Dr.N.G.P Institute of TechnologyCoimbatore641048India

Agriculture 4.0,as the future of farming technology,comprises numerous key enabling technologies towards sustainable *** use of state-of-the-art technologies,such as the Internet of Things,transform traditional cultivation practices,like irrigation,to modern solutions of precision *** achieve effectivewater resource usage and automated irrigation in precision agriculture,recent technologies like machine learning(mL)can be *** this motivation,this paper design an IoT andmL enabled smart irrigation system(IoTmL-SIS)for precision *** proposed IoTmL-SIS technique allows to sense the parameters of the farmland and make appropriate decisions for *** proposed IoTmL-SIS model involves different IoT based sensors for soil moisture,humidity,temperature sensor,and ***,the sensed data are transmitted to the cloud server for processing and decision ***,artificial algae algorithm(AAA)with least squares-support vector machine(LS-SVm)model is employed for the classification process to determine the need for ***,the AAA is applied to optimally tune the parameters involved in the LS-SVm model,and thereby the classification efficiency is significantly *** performance validation of the proposed IoTmL-SIS technique ensured better performance over the compared methods with the maximum accuracy of 0.975.

关键词： Automatic irrigation precision agriculture smart farming machine learning cloud computing decision making internet of things