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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

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

Layered double hydroxide photocatalysts for solar fuel production

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Chinese Journal of Catalysis 2021年第11期42卷 1944-1975页

作者： Kailin Wang Tianqi Wang Quazi Arif islam Yan Wu Engineering Research Center of Nano-Geo Materials of Ministry of Education Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan 430074HubeiChina

Splitting water or reducing CO_(2) via semiconductor photocatalysis to produce H2 or hydrocarbon fuels through the direct utilization of solar energy is a promising approach to mitigating the current fossil fuel energy crisis and environmental *** enables not only the realization of clean,renewable,and high-heating-value solar fuels,but also the reduction of CO_(2) *** double hydroxides(LDHs)are a type of two-dimensional anionic clay with a brucite-like structure,and are characterized by a unique,delaminable,multidimensional,layered structure;tunable intralayer metal cations;and exchangeable interlayer guest ***,it has been widely investigated in the fields of CO_(2) reduction,photoelectrocatalytic water oxidation,and water photolysis to produce ***,the low carrier mobility and poor quantum efficiency of pure LDH limit its *** increasing number of scholars are exploring methods to obtain LDH-based photocatalysts with high energy conversion efficiency,such as assembling photoactive components into LDH laminates,designing multidimensional structures,or coupling different types of semiconductors to construct *** review first summarizes the main characteristics of LDH,i.e.,metal-cation tunability,intercalated guest-anion substitutability,thermal decomposability,memory effect,multidimensionality,and ***,LDHs,LDH-based composites(metal sulfide-LDH composites,metal oxide-LDH composites,graphite phase carbon nitride-LDH composites),ternary LDH-based composites,and mixed-metal oxides for splitting water to produce H_(2) are ***,graphite phase carbon nitride-LDH composites,MgAl-LDH composites,CuZn-LDH composites,and other semiconductor-LDH composites for CO_(2) reduction are *** the field of LDH-based photocatalysts has advanced considerably,the photocatalytic mechanism of LDHs has not been thoroughly elucidated;moreover,the photocatalytic active sites,the syne

关键词： Layered double hydroxides Hydrotalcite H_(2) production CO_(2) reduction Photocatalysis Solar fuel production

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

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

Origin of the regional stress field along the Liquine-Ofqui Fault Zone(LOFZ),Southern Chilean Andes by means of FE Simulation

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Journal of Mountain Science 2009年第1期6卷 1-13页

作者： Md.Rafiqul islam Department of Physics and Earth Sciences University of the RyukyusOkinawa 903-0213 Japan

The Liquine-Ofqui Fault Zone(LOFZ) of southern Chilean Andes is one of the largest active strike-slip fault *** is an ongoing debate regarding the origin of the stress field along the LOFZ due to its complex *** paper represents a study of the origins of the LOFZ regional stress *** fields are calculated by finite element(FE) *** two possible stress origins, i.e., oblique plate convergence and ridge collision/indenter tectonics of Chile ridge against Peru-Chile trench, have been emphasized in the present *** types of boundary conditions for the three particular models have been applied to calculate stress *** are assumed to be elastic and plane stress *** results are presented in terms of four parameters, i.e., orientation of maximum horizontal stress(σ H max ), displacement vector, s train distribution, and maximum shear stress(τmax ) contour line within the *** results of the first model with oblique plate convergence show inconsistency between the geometric shape of the LOFZ and the distribution of the four *** more realistic results are obtained from the second model with normal ridge collision, there are few coincident in the LOFZ geometry and regional stress *** third model with normal and oblique ridge collision is reasonable in understanding the origin of stress field and geometrical condition in the lithosphere of the LOFZ.

关键词： Liquine-Ofqui Fault Zone FE analysis Elastic rheology Oblique plate convergence Ridgecollision.

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)

Remimazolam for sedation in gastrointestinal endoscopy:A comprehensive review

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World Journal of Gastrointestinal Endoscopy 2024年第7期16卷 385-395页

作者： Dushyant Singh Dahiya Ganesh Kumar Syeda Parsa Manesh Kumar Gangwani Hassam Ali Amir Humza Sohail Saqr Alsakarneh Umar Hayat Sheza Malik Yash R Shah Bhanu Siva Mohan Pinnam Sahib Singh islam Mohamed Adishwar Rao Saurabh Chandan Mohammad Al-Haddad Division of Gastroenterology Hepatology&MotilityThe University of Kansas School of MedicineKansas CityMO 66160United States Department of Internal Medicine Chandka Medical CollegeSindh 77280Pakistan Department of Gastroenterology and Hepatology University of Arkansas For Medical SciencesLittle RockAR 72205United States Division of Gastroenterology Hepatology and NutritionEast Carolina University/Brody School of MedicineGreenvilleNC 27858United States Department of Surgery University of New Mexico School of MedicineAlbuquerqueNM 87106United States Department of Internal Medicine University of Missouri-Kansas CityKansas CityMO 64108United States Department of Internal Medicine Geisinger Wyoming Valley Medical CenterWilkes BarrePA 18711United States Department of Internal Medicine Rochester General HospitalRochesterNY 14621United States Department of Internal Medicine Trinity Health Oakland/Wayne State UniversityPontiacMI 48341United States Department of Internal Medicine John H.Stroger Hospital of Cook CountyChicagoIL 60612United States Department of Internal Medicine Sinai hospitalBaltimoreMD 21215United States Department of Hepatology University of MissouriColumbiaMO 65211United States Department of Internal Medicine Guthrie Robert Packer HospitalSayrePA 18840United States Division of Gastroenterology and Hepatology Creighton University School of MedicineOmahaNE 68131United States Division of Gastroenterology and Hepatology Indiana University School of MedicineIndianapolisIN 46202United States

Worldwide,a majority of routine endoscopic procedures are performed under some form of sedation to maximize patient ***,benzodiazepines and opioids continue to be widely ***,in recent years,Remimazolam is gaining immense popularity for procedural sedation in gastrointestinal(GI)*** is an ultra-short-acting benzodiazepine sedative which was approved by the Food and Drug Administration in July 2020 for use in procedural *** has shown a favorable pharmacokinetic and pharmacodynamic profile in terms of its non-specific metabolism by tissue esterase,volume of distribution,total body clearance,and negligible drug-drug *** also has satisfactory efficacy and has achieved high rates of successful sedation in GI ***,studies have demonstrated that the efficacy of Remimazolam is non-inferior to Propofol,which is currently a gold standard for procedural sedation in most parts of the ***,the use of Propofol is associated with hemodynamic instability and respiratory *** contrast,Remimazolam has lower incidence of these adverse effects intra-procedurally and hence,may provide a safer alternative to Propofol in procedural *** this comprehensive narrative review,highlight the pharmacologic characteristics,efficacy,and safety of Remimazolam for procedural *** also discuss the potential of Remimazolam as a suitable alternative and how it can shape the future of procedural sedation in gastroenterology.

关键词： Remimazolam Endoscopy Sedation Outcomes Efficacy Safety Pharmacokinetics

Artifact suppression and analysis of brain activities with electroencephalography signals

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Neural Regeneration Research 2013年第16期8卷 1500-1513页

作者： Md. Rashed-Al-Mahfuz Md. Rabiul islam Keikichi Hirose Md. Khademul islam Molla Department of Computer Science and Engineering Pabna University of Science and Technology Department of Information and Communication Engineering The University of Tokyo Department of Computer Science and Engineering Rajshahi University

Brain-computer interface is a communication system that connects the brain with computer （or other devices） but is not dependent on the normal output of the brain （i.e., peripheral nerve and muscle）. Electro-oculogram is a dominant artifact which has a significant negative influence on further analysis of real electroencephalography data. This paper presented a data adaptive technique for artifact suppression and brain wave extraction from electroencephalography signals to detect regional brain activities. Empirical mode decomposition based adaptive thresholding approach was employed here to suppress the electro-oculogram artifact. Fractional Gaussian noise was used to determine the threshold level derived from the analysis data without any training. The purified electroencephalography signal was composed of the brain waves also called rhythmic components which represent the brain activities. The rhythmic components were extracted from each electroencephalography channel using adaptive wiener filter with the original scale. The regional brain activities were mapped on the basis of the spatial distribution of rhythmic components, and the results showed that different regions of the brain are activated in response to different stimuli. This research analyzed the activities of a single rhythmic component, alpha with respect to different motor imaginations. The experimental results showed that the proposed method is very efficient in artifact suppression and identifying individual motor imagery based on the activities of alpha component.

关键词： neural regeneration brain activity brain waves data adaptive filtering electroencephalography electro-oculogram artifact topographic mapping Wiener filtering neuroregeneration