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Composite Solid Rocket Propellant Based on GAP Polyurethane Matrix with Different Binder Contents

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火炸药学报 2020年第4期43卷 362-367页

作者： islam KBoshra Ahmed Elbeih GUO Lin Mohamed GZaki School of Chemistry and Environment Beihang UniversityBeijing 100191China Military technical College Kobry ElkobbahCairoEgypt

Different GAP-based CSRP samples with different binder contents were prepared and compared with that of conventional HtPB *** crosslinker mixture of trimethylol propane(tMP)and butane diol(BD)was used in the GAP matrix beside the addition of dibutyltin dilaurate(DBtDL)to ensure cross-linking and curing completion of the prepared *** viscosity and hardness of all prepared formulations were monitored continuously during the curing *** mechanical characteristics of cured samples were *** burning rate at operating pressure and specific impulse were measured,while the theoretical specific impulse(I sp)was calculated by ICt code and compared with the measured *** to the results,DOA was found to be a suitable plasticizer for GAP when using in *** mechanical properties of CSRP with 25%GAP can produce the optimum mechanical behavior,which is close to that of HtPB-based *** optimum GAP-based formulation is one candidate to replace the traditional HtPB-based CSRP with high burning rate for some applications.

关键词： physical chemistry glycidyl azide polymer(GAP) hydroxyl terminated polybutadiene(HtPB) cross-linker mechanical properties

A critical review of the emerging research on the detection and assessment of microplastics pollution in the coastal,marine,and urban Bangladesh

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Frontiers of Environmental Science & Engineering 2022年第10期16卷 39-52页

作者： Zaki Alam Pushan Ehsanur Rahman Nafisa islam Nirupam Aich Department of Chemical Engineering Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh Department of Civil Environmentaland Geo-EngineeringUniversity of Minnesota-Twin CitiesMinneapolisMN 55455USA Department of Civil Structural and Environmental EngineeringUniversity at BuffaloThe State University of New YorkBuffaloNY 14260USA

the research on the extent and effects of microplastics pollution in the Global South is only getting *** is a South Asian country with one of the fastest growing economies in the world,however,such exponential economic growth has also increased the pollution threats to its natural and urban *** this paper,we reviewed the recent primary research on the assessment of the extent of microplastics pollution in *** online databases,we developed a compilation of emergingresearch articles that detected and quantified microplastics in different coastal,marine,and urban environments in *** of the studies focused on the coastal environment(e.g.,beach sediment)and marine fish,while limited data were available for the urban *** also discussed the relationship of the type of anthropogenic activities with the observed microplastic *** Cox's Bazar sea beach in south-east Bangladesh experienced microplastics pollution due to tourism activities,while fishing and other anthropogenic activities led to microplastics pollution in the Bay of *** microplastics larger than 1 mm were prevalent in the beach sediments,smaller microplastics with size below 0.5 mm were prevalent in marine fish ***,the differences m microplastic abundance,size,shape,color,and polymer type found were depended on the sampling sites and relevant anthropogenic *** is imperative to identify majorsources of microplastics pollution in both natural and urban environment,determine potential environmental and human health effects,and develop mitigating and prevention strategies for reducing microplastics pollution.

关键词： Plastic pollution Waste management Global south Sustainability Marine pollution

the impact of alpha-fetoprotein (AFP), child-turcotte-pugh (CtP) score and disease staging on the survival of hepatocellular carcinoma (HCC) patients: a retrospective cohort from single oncology center

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Oncology research 2025年第1期33卷 149-160页

作者： Nasser Mulla Yousef Katib Asim M Almughamsi Duaa S Alkhayat Mohamed Mosaad Samir t Alfotih Rawan Alaofi Department of Internal Medicine Faculty of Medicine Taibah University Madinah 42278 Saudi Arabia. Department of Radiology Faculty of Medicine Taibah University Madinah 42278 Saudi Arabia. Department of Surgery Faculty of Medicine Taibah University Madinah 42278 Saudi Arabia. Department of Endemic and Infectious Diseases Suez Canal University Ismailia 41522 Egypt. King Salman bin Abdulaziz Medical City Madinah 42311 Saudi Arabia. Prince Mohammed Bin Abdulaziz Hospital Madinah 41511 Saudi Arabia.

Background:Hepatocellular carcinoma (HCC) is the most common cause of cancer-related death in Saudi Arabia. Our study aimed to investigate the patterns of HCC and the effect of tNM staging, Alfa-fetoprotein (AFP), and Child-turcotte Pugh (CtP) on patients' overall survival (OS).Methods:A retrospective analysis was conducted on 43 HCC patients at a single oncology center in Saudi Arabia from 2015 to 2020. All patients had to fulfill one of the following criteria: (a) a liver lesion reported as definitive HCC on dynamic imaging and/or (b) a biopsy-confirmed diagnosis.Results:the mean patient age of all HCC cases was 66.8 with a male-to-female ratio of 3.3:1. All patients were stratified into two groups: viral HCC (n = 22, 51%) and non-viral HCC (n = 21, 49%). Among viral-HCC patients, 55% were due to HBV and 45% due to HCV. Cirrhosis was diagnosed in 79% of cases. Age and sex did not significantly statistically differ in OS among viral and non-viral HCC patients (-value > 0.05). About 65% of patients had tumor size >5 cm during the diagnosis, with a significant statistical difference in OS (-value = 0.027). AFP was >400 ng/ml in 45% of the patients. there was a statistically significant difference in the OS in terms of AFP levels (-value = 0.021). A statistically significant difference was also observed between the CtP score and OS (-value = 0.02). CtP class B had the longest survival. BSC was the most common treatment provided to HCC patients followed by sorafenib therapy. there was a significant statistical difference in OS among viral and non-viral HCC patients (-value = 0.008).Conclusions:the most common predictors for OS were the underlying cause of HCC, AFP, and tumor size. Being having non-viral etiology, a tumor size >5 cm, an AFP > 400 ng/mL, and a CtP score class C were all negatively associated with OS.

关键词： Alpha-fetoprotein (AFP) Child-turcotte-pugh Hepatocellular carcinoma Pattern Progression free survival

Noise Reduction technique Applied to the Multichannel Analysis of Surface Waves

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Acta Geologica Sinica(English Edition) 2012年第5期86卷 1306-1311页

作者： taohidul islam Zamri CHIK Mohd Marzuki MUStAFA Department of Civil and Structural Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia43600 BangiMalaysia Department of Electrical and Electronics Engineering Patuakhali Science and Technology University8602 PatuakhaliBangladesh Department of Electrical and Electronics and System Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia43600 BangiMalaysia

this paper shows the presence of noises and technique to reduce these noises during the surface wave analysis. the frequency-dependent properties of Rayleigh-type surface waves can be used for imaging and characterizing the shallow subsurface. Interference by coherent source-generated noise inhibits the reliability of shear-wave velocities determined through inversion of the phase velocities of Rayleigh waves. Among these interferences by non-planar, non-fundamental mode Rayleigh waves （noise） are body waves, scattered and non-source-generated surface waves, and highermode surface waves. For the reduction of noise, the filtering technique is implemented in this paper for the multichannel analysis of surface wave method （MASW）. With the de-noising technique during the MASW method, more robust and reliable outcome is achieved. the significance of this paper is to obtain pre-awareness about noises during surface wave analysis and take better outcomes with denoising performance in near surface soil investigations.

关键词： multichannel analysis of surface wave method noises filtering near surface soil

Exact solutions for different vorticity functions of couple stress fluids

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第5期9卷 672-680页

作者： Saeed islam Chao-ying ZHOU Xiao-juan RAN Department of Mechanical Engineering and Automation Harbin Institute of technology Shenzhen Graduate School Shenzhen 518055 China COMSAtS Institute of lnformation technology Islamabad 44000 Pakistan

In this paper, inverse solutions are obtained for the class of 2D steady incompressible couple stress fluid flows. this class consists of flows for which the vorticity distribution is given by ▽2ψ=ψ+f(x,y). the solutions are obtained by applying the inverse method, which makes certain hypotheses regarding the form of the velocity field and pressure but without making any regarding the boundaries of the domain occupied by the fluid. Inverse solutions are derived for three different forms of f(x,y).

关键词： Exact solutions Vorticity functions Beltrami flow Couple stress fluid

Hot-pressed graphene nanoplatelets or/and zirconia reinforced hybrid alumina nanocomposites with improved toughness and mechanical characteristics

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Journal of Materials Science & technology 2020年第5期40卷 135-145页

作者： Iftikhar Ahmad Mohammad islam Nuha Al Habis Shahid Parvez Center of Excellence for Research in Engineering Materials Deanship of Scientific ResearchKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia Mechanical Engineering Department College of EngineeringKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia

this work explains the synergistic contribution of graphene nanoplatelets(GNP)and zirconia ceramic nanoparticles(ZrO2)on the microstructure,mechanical performance and ballistic properties of the alumina(Al2O3)ceramic hybrid *** the benchmarked monolithic alumina,the hotpressed hybrid nanocomposite microstructure demonstrated 68%lower grain size due to grain pinning phenomenon by the homogenously distributed reinforcing GNP(0.5 wt%)and zirconia(4 wt%)***,the hybrid nanocomposite manifested 155%better fracture toughness(KIC)and 17%higher microhardness as well as 88%superior ballistic trait over the monolithic alumina,*** superior mechanical and ballistic performance of the hybrid nanocomposites was attributed to the combined role of zirconia nanoparticles and GNP nanomaterial in refining the microstructure and inducing idiosyncratic strengthening/toughening *** combined electron microscopy revealed complicated physical interlocking of the GNP into the microstructure as well as excellent bonding of the GNP with alumina at their interface in the hybrid *** also probed the efficiency of the pull-out and crack-bridging toughening mechanisms through proven quantitative *** on the information extracted from the in-depth SEM/tEM investigation,we outlined schematic models for understating the reinforcing ability as well as toughening mechanisms in the hybrid nanocomposites and meticulously *** hot-pressed hybrid nanocomposites owning high toughness and hardness may have applications in advanced armor technology.

关键词： Graphene Alumina Zirconia toughness Hybrid nanocomposites

Multi-level supervisory emergency control for operation of remote area microgrid clusters

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Journal of Modern Power Systems and Clean Energy 2019年第5期7卷 1210-1228页

作者： Munira BAtOOL Farhad SHAHNIA Syed M.islam School of Electrical Engineering Computing and Mathematical SciencesCurtin UniversityPerthAustralia School of Engineering and Information technology Murdoch UniversityPerthAustralia School of Science Engineering and Information TechnologyFederation UniversityBallaratAustralia

Remote and regional areas are usually supplied by isolated and self-sufficient electricity systems,which are called as microgrids(MGs).to reduce the overall cost of electricity production,MGs rely on non-dispatchable renewable *** such as overloading or excessive generation by renewable sources can result in a substantial voltage or frequency deviation in *** paper presents a supervisory controller for such *** key idea is to remedy the emergencies by optimal internal or external support.A multi-level controller with soft,intermedial and hard actions is *** soft actions include the adjustment of the droop parameters of the sources and the controlling of the charge/discharge of energy *** intermedial action is exchanging power with neighboring MGs,which is highly probable in large remote *** the last remedying resort,curtailing loads or renewable sources are assumed as hard *** proposed controller employs an optimization technique consisting of certain objectives such as reducing power loss in the tie-lines amongst MGs and the dependency of an MG to other MGs,as well as enhancing the contribution of renewable sources in electricity *** of the fuel consumption and emissions of conventional generators,along with frequency and voltage deviation,is the other desired *** performance of the proposal is evaluated by several numerical analyses in MAtLAB~?.

关键词： Microgrids Emergency controller Optimization Remote area

Characterization of aerodynamic performance of wind-lens turbine using high-fidelity CFD simulations

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Frontiers in Energy 2022年第4期16卷 661-682页

作者： islam HASHEM Aida A.HAFIZ Mohamed H.MOHAMED Mechanical Power Engineering Department Faculty of Engineering-MatariaHelwan UniversityCairo 11718Egypt State Key Laboratory of Hydroscience and Engineering Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Mechanical Engineering Department College of Engineering and Islamic ArchitectureUmm Al-Qura UniversityMakkah5555Saudi Arabia

Wind-lens turbines(WLts)exhibit the prospect of a higher output power and more suitability for urban areas in comparison to bare wind *** wind-lens typically comprises a diffuser shroud coupled with a flange appended to the exit periphery of the ***-lenses can boost the velocity of the incoming wind through the turbine rotor owing to the creation of a lowpressure zone downstream the flanged *** this paper,the aerodynamic performance of the wind-lens is computationally assessed using high-fidelity transient CFD simulations for shrouds with different profiles,aiming to assess the effect of change of some design parameters such as length,area ratio and flange height of the diffuser shroud on the power *** power coefficient(Cp)is calculated by solving the URANS equations with the aid of the SSt k–ω***,comparisons with experimental data for validation are accomplished to prove that the proposed methodology could be able to precisely predict the aerodynamic behavior of the windlens *** results affirm that wind-lens with cycloidal profile yield an augmentation of about 58%increase in power coefficient compared to bare wind turbine of the same rotor *** is also emphasized that diffusers(cycloid type)of small length could achieve a twice increase in power coefficient while maintaining large flange heights.

关键词： shroud diffuser-augmented wind turbine(DAWt) Betz limit aerodynamics computational fluid dynamics(CFD)

Nature-inspired Hybrid Optimization Algorithms for Load Flow Analysis of Islanded Microgrids

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Journal of Modern Power Systems and Clean Energy 2020年第6期8卷 1250-1258页

作者： Saad Mohammad Abdullah Ashik Ahmed Quazi Nafees Ul islam the Department of Electrical and Electronic Engineering Islamic University of TechnologyBoard BazarGazipur 1704Bangladesh

Load flow analysis is a significant tool for proper planning,operation,and dynamic analysis of a power system that provides the steady-state values of voltage magnitudes and angles at the fundamental ***,due to the absence of a slack bus in an islanded microgrid,modified load flow algorithms should be adopted considering the system frequency as one of the solution *** paper proposes the application of nature-inspired hybrid optimization algorithms for solving the load flow problem of islanded *** nature-inspired algorithms such as genetic algorithm(GA),differential evolution(DE),flower pollination algorithm(FPA),and grasshopper optimization algorithm(GOA)are separately merged with imperialistic competitive algorithm(ICA)to form four hybrid algorithms named as ICGA,ICDE,ICFPA,and *** of these algorithms are tested on the 6-bus test system and the modified IEEE 37-bus test system.A comparison among the proposed algorithms is carried out in terms of statistical analysis conducted using SPSS statistics *** the statistical analysis,it is identified that on an average,ICDE takes less number of iterations and consequently needs less execution time compared with other algorithms in solving the load flow problem of islanded microgrids.

关键词： Nature-inspired hybrid algorithm global optimization islanded microgrid load flow analysis