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Synthesis and study the influence of yttrium doping on band structure,optical,non-linear optical and dielectric results for Ca_(12)Al_(14)O_(33) (C12A7) single crystals grown using traveling-solvent floating zone (TSFZ) method

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Chinese Physics B 2022年第1期31卷 626-630页

作者： A.abdel Moez Ahmed I.Ali A.Tayel Solid State Physics Department Physical Research DivisionNational Research Centre(NRC)33 El Bohouth StreetDokkiGiza 12622Egypt Basic Science Department Faculty of Faculty of Technology and EducationHelwan UniversityKobry El-QopaCairo 11281Egypt

Ca_(12)Al_(14)O_(33)(C12A7)and Y_(0.02)Ca_(11.98)Al_(14)O_(33)(Y-C12A7)single crystals were grown by using the traveling-solvent floating zone(TSFZ)*** temperature was increased to avoid the bubbles and cracks which may be formed during the preparation of the ingot *** have started with the flux higher than the normal to avoid the bubbles and make good treatment for the solid-liquid *** structures of both Ca_(12)Al_(14)O_(33)(C12A7)and Y_(0.02)Ca_(11.98)Al_(14)O_(33)(Y-C12A7)were studied by using x-ray diffraction(XRD).Optical properties for C12A7 and Y-C12A7 single crystals have been studied in order to determine the optical parameters such as optical energy gap(Eg),refractive index n,oscillating energy(Eo),dispersion energy(Ed),volume energy loss function(VELF),and surface energy loss function(SELF).Finally,a new result for these samples is that the third-order nonlinear optical susceptibility(χ(3))was *** results have been discussed with effect of Y-doping on the C12A7 single crystals for optical and industrial applications.

关键词： syntheses Ca_(12)Al_(14)O_(33)(C12A7)single crystals Y-doping optical parameters dielectric results nonlinear optical susceptibility

Deep oxidative desulfurization of gas oil based on sandwich-type polysilicotungstate supported β-cyclodextrin composite as an efficient heterogeneous catalyst

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Chinese Journal of Chemical Engineering 2019年第10期27卷 2418-2426页

作者： Mohammad Ali Rezvani Sahar Khandan negin Sabahi hamid Saeidian Department of Chemistry Faculty of ScienceUniversity of ZanjanZanjanIran Department of Chemistry Payam Noor UniversityZanjanIran

In this work,in order to obtain deep clean gas oil,a novel organic–inorganic hybrid(n-C4H9)4n)7H5Si2W18Cd4O68@β-cyclodextrin(abbreviated as TBA-Si WCd@β-CD)composite was synthesized by supporting quaternary ammonium salt of sandwich-type polysilicotungstate onβ-cyclodextrin(TBA-SiWCd@β-CD)as an efficient catalyst for oxidative desulfurization(ODS)of gas *** successful composition of the materials explained by the formation of host–guest inclusion complex,which confirmed through FTIR,UV–vis,XRD,SEM,and EDX characterization *** results revealed that the levels of sulfur content and mercaptan compounds of gas oil lowered with 97%removal *** with the ODS treatment of gas oil,the TBA-Si WCd@β-CD composite showed an outstanding catalytic performance for the oxidation of dibenzothiophene(DBT)in the prepared model *** main factors that influence the desulfurization efficiency and the kinetic study of the ODS process were *** prepared heterogeneous catalyst was found to give remarkable reusability for five runs without a discernible decrease in its *** study suggested the potential application of the TBA-Si WCd@β-CD catalyst for removal of hazardous sulfur compounds from gas oil fuel.

关键词： Oxidative desulfurization Sandwich-type polyoxometalate β-Cyclodextrin Heterogeneous catalyst

Tracking Dengue on Twitter Using Hybrid Filtration-Polarity and Apache Flume

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Computer Systems Science & Engineering 2022年第3期40卷 913-926页

作者： norjihan Binti Abdul Ghani Suraya hamid Muneer Ahmad Younes Saadi n.Z.Jhanjhi Mohammed A.Alzain Mehedi Masud Department of Information Systems Faculty of Computer Science&Information TechnologyUniversiti Malaya50603Kuala LumpurMalaysia School of Computer Science and Engineering SCE Taylor’s UniversitySubang Jaya47500Malaysia Department of Information Technology College of Computers and Information TechnologyTaif UniversityTaif21944Saudi Arabia Department of Computer Science College of Computers and Information TechnologyTaif UniversityTaif21944Saudi Arabia

The world health organization(WHO)terms dengue as a serious illness that impacts almost half of the world’s population and carries no specific *** and accurate detection of spread in affected regions can save precious *** the severity of the disease,a few noticeable works can be found that involve sentiment analysis to mine accurate intuitions from the social media text ***,the massive data explosion in recent years has led to difficulties in terms of storing and processing large amounts of data,as reliable mechanisms to gather the data and suitable techniques to extract meaningful insights from the data are *** research study proposes a sentiment analysis polarity approach for collecting data and extracting relevant information about dengue via Apache *** method consists of two main parts:the first part collects data from social media using Apache Flume,while the second part focuses on querying and extracting relevant information via the hybrid filtration-polarity algorithm using Apache *** overcome the noisy and unstructured nature of the data,the process of extracting information is characterized by pre and post-filtration *** a result,only with the integration of Flume and Hive with filtration and polarity analysis,can a reliable sentiment analysis technique be offered to collect and process large-scale data from the social *** introduce how the Apache Hadoop ecosystem–Flume and Hive–can provide a sentiment analysis capability by storing and processing large amounts of *** important finding of this paper is that developing efficient sentiment analysis applications for detecting diseases can be more reliable through the use of the Hadoop ecosystem components than through the use of normal machines.

关键词： Big data analysis data filtration text analysis sentiment analysis social media event detection

Valence Stabilization of Fe(II) Ions during Extended Gamma Irradiation of Their Aqueous Acidic Solutions Containing Phenol, Acetone, 4-Ethylpyridine or Hydrazine Hydrate

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World Journal of nuclear Science and Technology 2015年第2期5卷 88-101页

作者： M. F. Barakat M. M. abdel hamid nuclear and Radiological Control Authority Cairo Egypt Hot Labs Center Atomic Energy Authority Cairo Egypt

Valence stabilization of polyvalent ions in acidic solutions during gamma irradiation is an important issue in nuclear aqueous chemical technology. Radiolysis and self irradiation problems encountered during chemical reprocessing of nuclear fuel or during chemical separation of transuranium elements or fission products are extremely important. Consequently studies on valence stabilization of polyvalent ions in strong gamma irradiation fields are very useful. In our previous publications, the valence stabilization of Fe(II) ions in acidic solutions during continuous gamma irradiation was achieved by using an inorganic compound;such as sodium sulfite, or some organic additives such as aliphatic alcohols, aldehyds or acids prior to irradiation. It was found that the efficiency of valence stabilization depends on the amount and chemical structure of the added compounds. In the present work, valence stabilization of divalent iron during gamma irradiation was studied in presence of some organic additives, belonging to some other classes of organic compounds such as Phenol (aromatic alcohol), Acetone (aliphatic ketone), 4-Aminopyridine (heterocyclic amino compound) and Hydrazine hydrate (aliphatic amino compound) to complement our previous studies. The results showed that valence stabilization of Fe(II) in presence of these compounds depends also on the amount and chemical structure of the additive used. Some interaction mechanisms have been proposed.

关键词： Water Radiolysis Valence Stabilization Extended Gamma Irradiation Competitive Reactions Polyvalent Ions Protective Effects

Characterization and beneficiation of the Egyptian black shale for possible extraction of organic matter

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International Journal of Mining Science and Technology 2014年第2期24卷 177-182页

作者： Abd El-Rahiem F.H. Hassan M.S. Selim K.A. abdel-Khalek n.A. Central Metallurgical Research and Development Institute

The present paper focuses on obtaining concentrate enriched with organic matter that could be suitable for a retorting process from black shale; this is black shale from the Safaga area on the Red Sea Coast. X-ray diffraction and optical polarising microscope are used in evaluating black shale minerals. Attrition scrubbing and flotation were conducted for enrichment of organic matter in the black shale sample. Mineralogical studies revealed that black shale samples contain bituminous calcareous clay stone, quartz, apatite and pyrite. Rabah mine black shale contains 28% organic matter. The results of the different separation techniques indicate that attrition and flotation techniques successively enriched the organic matter in the black shale. The organic matter could be enriched in the black shale and obtained a concen- trate with 59% assavinz and 85% recovery.

关键词： Black shale Kerogen Organic matter Attrition scrubbing Flotation

Aspects of Fretting Fatigue Finite Element Modelling

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Computers, Materials & Continua 2020年第7期64卷 97-144页

作者： Kyvia Pereira Libardo VVanegas-Useche Magd abdel Wahab Soete Laboratory Faculty of Engineering and ArchitectureGhent UniversityZwijnaardeB-9052Belgium Facultad de Ingeniería Mecánica Universidad Tecnológica de PereiraPereira660003Colombia Division of Computational Mechanics Ton Duc Thang UniversityHo Chi MinhVietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi MinhVietnam

Fretting fatigue is a type of failure that may affect various mechanical components,such as bolted or dovetail joints,press-fitted shafts,couplings,and *** to its importance,many researchers have carried out experimental tests and analytical and numerical modelling,so that the phenomena that govern the failure process can be understood or appropriately ***,the performance of systems subjected to fretting fatigue can be predicted and *** paper discusses different aspects related to the finite element modelling of fretting *** presents common experimental configurations and the analytical solutions for cylindrical ***,it discusses aspects of fretting fatigue crack initiation,such as crack location,orientation,and length,as well as stress averaging ***,it deals with the propagation stage;crack face interaction,orientation criteria,and crack growth rate are ***,additional aspects of recent research on fretting fatigue are reviewed:out-of-phase loading,cohesive zone modelling,wear effects,heterogeneity,and crystal *** fatigue is a phenomenon not well understood,and much more research is needed so that its understanding is increased and proper criteria and laws may be available for different cases.

关键词： Fretting fatigue FEM modelling crack initiation crack growth

Exponential nonlinear Observer Based on the Differential State-dependent Riccati Equation

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International Journal of Automation and computing 2012年第4期9卷 358-368页

作者： Hossein Beikzadeh hamid D.Taghirad Department of Electrical and Computer Engineering University of Alberta Faculty of Electrical and Computer Engineering K.N.Toosi University of Technology

This paper presents a novel nonlinear continuous-time observer based on the differential state-dependent Riccati equation (SDRE) filter with guaranteed exponential stability. Although impressive results have rapidly emerged from the use of SDRE designs for observers and filters, the underlying theory is yet scant and there remain many unanswered questions such as stability and convergence. In this paper, Lyapunov stability analysis is utilized in order to obtain the required conditions for exponential stability of the estimation error dynamics. We prove that under specific conditions, the proposed observer is at least locally exponentially stable. Moreover, a new definition of a detectable state-dependent factorization is introduced, and a close relation between the uniform detectability of the nonlinear system and the boundedness property of the state-dependent differential Riccati equation is established. Furthermore, through a simulation study of a second order nonlinear model, which satisfies the stability conditions, the promising performance of the proposed observer is demonstrated. Finally, in order to examine the effectiveness of the proposed method, it is applied to the highly nonlinear flux and angular velocity estimation problem for induction machines. The simulation results verify how effectively this modification can increase the region of attraction and the observer error decay rate.

关键词： Detectability direct method of Lyapunov exponential stability nonlinear observer region of attraction state-dependent Riccati equation (SDRE) technique

URAnS simulations for a free-running container ship:Part 2. Added power

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Journal of Hydrodynamics 2021年第3期33卷 448-467页

作者： Dong-Hwan Kim Yugo Sanada hamid Sadat-Hosseini Frederick Stern IIHR-Hydroscience and Engineering The University of IowaIowa CityUSA Costal Development and Ocean Energy Research Center Korea Institute of Ocean Science and TechnologyBusanKorea Mechanical Engineering University of North TexasDentonUSA

Part 2 reports the validation,local force and local flow study results for the free-running added power simulations whose conditions are the same as the self-propulsion test except for the increased propeller rotational speed and the presence of *** targeting the same mean Froude number in the wave condition,the propeller requires the increased propeller rotational speed for the operation at the low advance ratio due to the added *** test is performed at five different wavelengths in head waves and four different headings in the oblique *** the validation study,the time series of the validation variables is decomposed with discrete Fourier transform to extract the harmonic *** variables are global parameters,including motions,propeller thrust,and torque coefficients,added power variables,and self-propulsion factors which show reasonable agreement against the experiment results and produces a similar error from the self-propulsion *** local force study shows that the added resistance mostly appears at the bow due to the bow plunging during the short head wave and resonance *** contributions of the gravitational force and the buoyant force are found to increase as the stern motion exceeds the bow motion during the long head wave *** oscillation of the propeller performances shows correlation with the first harmonic amplitude of the propeller ***,pitch,and roll decay tests are performed prior to the main test to assess the natural frequencies of the *** as Part 1,a discretized propeller is used.

关键词： Added power unsteady Reynolds-averaged navier-Stokes(URAnS) KRISO Container Ship(KCS) CFDShip-IOWA

Risk-based maintenance scheduling of generating units in the deregulated environment considering transmission network congestion

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Journal of Modern Power Systems and Clean Energy 2014年第2期2卷 150-162页

作者： Hessam GOLMOHAMADI Maryam RAMEZAnI Amir BASHIAn hamid FALAGHI Faculty of Electrical and Computer Engineering The University of BirjandBirjandIran Department of Power Electrical Engineering Ferdowsi University of MashhadMashhadIran

In restructured power systems,the traditional approaches of unit maintenance scheduling(UMS)need to undergo major changes in order to be compatible with new competitive *** the maintenance on generating units may decrease the security level of transmission network and result in electricity shortage in power system;as a result,it can impose a kind of cost on transmission network as called security ***,taking off line a generating unit for performing maintenance can change power flow in some transmission lines,and may lead to network *** this study,generating unit maintenance is scheduled considering security and congestion cost with n-1 examination for transmission lines random *** proposed UMS approach would lead to optimum operation of power system in terms of economy and *** achieve this goal,the optimal power flow(OPF)compatible with market mechanism is ***,the electricity price discovery mechanism as locational marginal pricing(LMP)is restated to analyze the impacts of UMS on nodal electricity *** security and congestion cost simultaneously,this novel approach can reveal some new costs which are imposed to transmission network on behalf of generation units;as a result,it provides a great opportunity to perform maintenance in a fair environment for both generating companies(GenCo)and transmission companies(TransCo).At the end,simulation results on nine-bus test power system demonstrate that by using this method,the proposed UMS can guarantee fairness among market participants including GenCos and TransCo and ensure power system security.

关键词： Congestion Security Transmission network Unit maintenance scheduling