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Exergetic sustainability evaluation and optimization of an irreversible Brayton cycle performance

Frontiers in Energy 2019年第2期13卷 399-410页

作者： Mohammad H. AHMADI Mohammad-Ali AHMADI Esmaeil ABOUKAZEMPOUR Lavinia GROSU Fathollah POURFAYAZ mokhtar bidi Renewable Energies Faculty of New Sciences and Technologies University of Tehran Tehran *** Iran Department of Petroleum Engineering Ahwaz Faculty of Petroleum Engineering Petroleum University of Technology (PUT) Ahwaz 61963165 Iran Graduate School of the Environment and Energy Science and Research Branch Islamic Azad University Tehran *** Iran University of Paris Ouest Nanterre La Defense 50 rue Sevres 92 410 Ville dAvray France Faculty of Mechanical & Energy Engineering Shahid Beheshti University A.C.Tehran ***Iran

Owing to the energy demands and global warming issue, employing more effective power cycles has become a responsibility. This paper presents a thermo-dynamical study of an irreversible Brayton cycle with the aim of optimizing the performance of the Brayton cycle. Moreover, four different schemes in the process of multi-objective optimization were suggested, and the outcomes of each scheme are assessed separately. The power output, the concepts of entropy generation, the energy, the exergy output, and the exergy efficiencies for the irreversible Brayton cycle are considered in the analysis. In the first scheme, in order to maximize the exergy output, the ecological function and the ecological coefficient of performance, a multi-objective optimization algorithm (MOEA) is used. In the second scheme, three objective functions including the exergetic performance criteria, the ecological coefficient of performance, and the ecological function are maximized at the same time by employing MOEA. In the third scenario, in order to maximize the exergy output, the exergetic performance criteria and the ecological coefficient of performance, a MOEA is performed. In the last scheme, three objective functions containing the exergetic performance criteria, the ecologi-cal coefficient of performance, and the exergy-based ecological function are maximized at the same time by employing multi-objective optimization algorithms. All the strategies are implemented via multi-objective evolu-tionary algorithms based on the NSGAII method. Finally, to govern the final outcome in each scheme, three well- known decision makers were employed.

关键词： entropy generation exergy Brayton cycle ecological function irreversibility

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Wave propagation of a functionally graded plate via integral variables with a hyperbolic arcsine function

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 547-561页

作者： mokhtar Ellali mokhtar Bouazza Ashraf M.Zenkour Smart structures Laboratory University of Ain TemouchentAin Temouchent 46000Algeria Department of Civil Engineering University Tahri Mohamed of BecharBechar 08000Algeria Department of Mathematics Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia Laboratory of Materials and Hydrology(LMH) University of Sidi Bel AbbesSidi Bel Abbes 22000Algeria Department of Mathematics Faculty of ScienceKafrelsheikh UniversityKafrelsheikh 33516Egypt

Several studies on functionally graded materials(FGMs)have been done by researchers,but few studies have dealt with the impact of the modification of the properties of materials with regard to the functional propagation of the waves in *** work aims to explore the effects of changing compositional characteristics and the volume fraction of the constituent of plate materials regarding the wave propagation response of thick plates of *** model is based on a higher-order theory and a new displacement field with four unknowns that introduce indeterminate integral variables with a hyperbolic arcsine *** FGM plate is assumed to consist of a mixture of metal and ceramic,and its properties change depending on the power functions of the thickness of the plate,such as linear,quadratic,cubic,and inverse *** utilizing Hamilton’s principle,general formulae of the wave propagation were obtained to establish wave modes and phase velocity curves of the wave propagation in a functionally graded plate,including the effects of changing compositional characteristics of materials.

关键词： FGM plate effects of material properties wave propagation indeterminate integral variables inverse sinus hyperbolic function

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Assessment of micro-scale heat exchangers efficiency using lattice Boltzmann method and design of experiments

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Energy and Built Environment 2024年第6期5卷 840-852页

作者： mokhtar Ferhi Sameh Abidi Ridha Djebali Fateh Mebarek-Oudina UR22ES12:Modeling Optimization and Augmented Engineering ISLAIBUniversity of JendoubaBéja 9000Tunisia Higher Institute of Humanities of Jendouba University of JendoubaTunisia Department of Management Information Systems College of Business AdministrationQassim UniversityAl-RassAl-QassimSaudi Arabia Department of Physics Faculty of SciencesUniversity of 20 août 1955-SkikdaB.P 26 Road El-HadaiekSkikda 21000Algeria Laboratoire des Matériaux et Génie Energétique(LMGE) University of 20 août 1955-SkikdaSkikda 21000Algeria

The study is focused on the use of nanofluids in a micro-open tall cavity,which is a type of micro heat exchanger(MHE).The cavity is heated from the bottom sidewall in a sinusoidal pattern,and the effects of four input parameters(Ra,Ha,Kn,and Vf)on heat transfer and irreversibility are investigated using numerical simulations based on Lattice Boltzmann Method(LBM).The findings of the study suggest that the local heat transfer on the bottom sidewall is strongly influenced by Ra and Ha,while the surface distribution of entropy generation is mainly dependent on *** study also shows that the optimization of the magnitude and wavelength of the sinusoidal temperature can improve both local heat transfer and surface distribution of entropy *** results of the study provide valuable insights into the design of micro heat exchangers and suggest that the optimization of micro-porous geometries using DOE could lead to increased energy *** study contributes to our understanding of the complex interactions between input parameters in micro heat exchangers and highlights the importance of considering multiple parameters in the design process.

关键词： MHD Slip flow regime Micro heat exchanger Design of experiments Optimization

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Evolution of the“ancient Kedah”:A study on urban forms at Sungai Batu Archaeological Complex(SBAC),Bujang Valley,Kedah,Malaysia

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Frontiers of Architectural Research 2024年第1期13卷 127-143页

作者： Mohd Hasfarisham Abd Halim Naizatul Akma Mohd mokhtar Nor Khairunnisa Talib Shyeh Sahibul Karamah Masnan Ahmad Fadly Jusoh mokhtar Saidin Kedah Malaysia Universiti Utara Malaysia KedahMalaysia Universiti Sains Malaysia PenangMalaysia

Archaeological research at the Sungai Batu Archaeological Complex(SBAC),which has been carried out until 2023,aims to complete the chronological data and urbanization process of the ancient *** study will especially prove that the ongoing urbanization process is aimed at developing the iron smelting industry and trade in ancient Kedah,especially in *** is because archaeological research at SBAC has proven that with the existence of the ancient Kedah iron smelting workshop at SBAC,river jetties,port management,rituals,and Buddhist monuments began to be erected,all of which can be determined by chronometric *** results of the chronometric dating have proven that the ancient Kedah Kingdom existed since the 6th century BC and was oriented towards the trade of iron resources,which allowed the use of the area to grow *** process of urbanization and land use clearly conforms to Lynch’s principle,which emphasizes the principles of 1)paths,2)edges,3)districts,4)nodes,and 5)landmarks in the development process of land use and urbanization in the complex.

关键词： Chronometric dating Urbanization Land use Monument Iron smelting site

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Research progress in friction stir processing of magnesium alloys and their metal matrix surface composites: Evolution in the 21^(st )century

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Journal of Magnesium and Alloys 2024年第6期12卷 2091-2146页

作者： Roshan Vijay Marode Tamiru Alemu Lemma Nabihah Sallih Srinivasa Rao Pedapati mokhtar Awang Adeel Hassan Department of Mechanical Engineering Universiti Teknologi PETRONASBandarSeri IskandarPerak 32610Malaysia Department of Mechanical Engineering College of EngineeringThe University of Texas Permian BasinMidland-OdessaUnited States Mechanical Engineering Department Universiti Teknologi BruneiBrunei

Rising concerns about climate change drive the demand for lightweight ***(Mg)alloys are highly valued for their low weight,making them increasingly important in various *** focusing on enhancing the characteristics of Mg alloys and developing their Metal Matrix Composites(MMCs)have gained significant attention worldwide over the past decade,driven by the global shift towards lightweight *** Stir Processing(FSP)has emerged as a promising technique to enhance the properties of Mg alloys and produce ***,FSP adapted to refine grain size from the micro to the nano level and accelerated the development of MMCs due to its solid-state nature and the synergistic effects of microstructure refinement and reinforcement,improving strength,hardness,ductility,wear resistance,corrosion resistance,and fatigue ***,producing defect-free and sound FSPed Mg and Mg-MMCs requires addressing several variables and their interdependencies,which opens up a broad range of practical *** existing reviews on individual FSP of Mg,its alloys,and MMCs,an attempt has been made to analyze the latest research on these three aspects collectively to enhance the understanding,application,and effectiveness of FSP for Mg and its *** review article discusses the literature,classifies the importance of Mg alloys,provides a historical background,and explores developments and potential applications of FSPed Mg *** focuses on novel fabrication methods,reinforcement strategies,machine and tool design parameters,material characterization,and integration with other methods for enhanced *** influence of process parameters and the emergence of defects are examined,along with specific applications in mono and hybrid composites and their microstructure *** study identifies promising reinforcement materials and highlights research gaps in FSP for Mg alloys and MMCs *** conclude

关键词： Magnesium alloys Friction stir processing Metal matrix composites Lightweight Surface modification

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Challenges to establishing and maintaining kidney transplantation programs in developing countries:What are the coping strategies?

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World Journal of Methodology 2024年第2期14卷 1-16页

作者： Rabea Ahmed Gadelkareem Amr Mostafa Abdelgawad Nasreldin Mohammed Mohammed Ali Zarzour Mahmoud Khalil Ahmed Reda Hisham mokhtar Hammouda Department of Urology Assiut Urology and Nephrology HospitalFaculty of MedicineAssiut UniversityAssiut 71515Egypt

Kidney transplantation(KT)is the optimal form of renal replacement therapy for patients with end-stage renal ***,this health service is not available to all patients,especially in developing *** deceased donor KT programs are mostly absent,and the living donor KT centers are ***-center studies presenting experiences from developing countries usually report a variety of *** review addresses these challenges and the opposing strategies by reviewing the single-center experiences of developing *** financial challenges hamper the infrastructural and material availability,coverage of transplant costs,and qualification of medical *** sociocultural challenges influence organ donation,equity of beneficence,and regular follow-up *** interests and motives for transplantation may result from high medicolegal responsibilities in KT practice,intense potential psychosocial burdens,complex qualification protocols,and low productivity or compensation for KT *** medical literacy about KT advantages is prevalent among clinicians,patients,and the *** inefficient organizational and regulatory oversight is translated into inefficient healthcare systems,absent national KT programs and registries,uncoordinated job descriptions and qualification protocols,uncoordinated on-site investigations with regulatory constraints,and the prevalence of commercial KT *** challenges resulted in noticeable differences between KT services in developed and developing *** coping strategies can be summarized in two main mechanisms:The first mechanism is maximizing the available resources by increasing the rates of living kidney donation,promoting the expertise of medical personnel,reducing material consumption,and supporting the establishment and maintenance of KT *** latter warrants the expansion of the public sector and the elimination of non-ethical KT *** second mechanism is recru

关键词： Challenges Coping strategies Developing countries Kidney transplantation Low resources Single-center

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An Efficient Fuzzy Logic Fault Detection and Identification Method of Photovoltaic Inverters

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Computers, Materials & Continua 2021年第5期67卷 2283-2299页

作者： mokhtar Aly Hegazy Rezk Department of Electrical Engineering Aswan UniversityAswan81542Egypt Electronics Engineering Department Universidad Tecnica Federico Santa MariaValparaiso2390123Chile College of Engineering at Wadi Addawaser Prince Sattam Bin Abdulaziz UniversityWadi Addawaser11991Saudi Arabia Electrical Engineering Department Faculty of EngineeringMinia UniversityMinia61111Egypt

Fuzzy logic control(FLC)systems have found wide utilization in several industrial *** paper proposes a fuzzy logic-based fault detection and identification method for open-circuit switch fault in grid-tied photovoltaic(PV)*** installations and ambitious plans have been recently achieved for PV systems as clean and renewable power generation sources due to their improved environmental impacts and availability *** converters represent the main parts for the grid integration of PV ***,PV power converters contain several power switches that construct their *** power switches in PV systems are highly subjected to high stresses due to the continuously varying operating ***,the grid-tied systems represent nonlinear systems and the system model parameters are changing ***,the grid-tied PV systems have a nonlinear factor and the fault detection and identification(FDI)methods based on using mathematical models become more *** proposed fuzzy logic-based FDI(FL-FDI)method is based on employing the fuzzy logic concept for detecting and identifying the location of various switch *** proposed FL-FDI method is designed and extracted from the analysis and comparison of the various measured voltage/current components for the control ***,the proposed FL-FDI method does not require additional components or measurement ***,the proposed method can detect the faulty condition and also identify the location of the faulty switch for replacement and maintenance *** proposed method can detect the faulty condition within only a single fundamental line period without the need for additional sensors and/or performing complex calculations or precise *** proposed FL-FDI method is tested on the widely used T-type PV inverter system,wherein there are twelve different switches and the FDI process represents a challenging *** results sho

关键词： Fault detection and identification fuzzy logic T-type inverter photovoltaic(PV)

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Portable device for the local three-dimensional deformation measurement using a single camera

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Science China(Technological Sciences) 2018年第1期61卷 51-60页

作者： MOHAMMED mokhtar Eisa SHAO XinXing HE XiaoYuan School of Civil Engineering Department of Engineering Mechanics Southeast University

The aim of this paper is to establish and validate a portable device for the local three dimensional deformation measurements using a single camera combined with a triangular prism mirror and two mirrors. The mirrors were utilized to convert a single camera into a stereo image system, which views a test object from two different directions and records the surface images of the test specimen on the two halves of the camera sensor in order to achieve a three-dimensional measurement. The proposed system consists of a single camera and the reflection system was integrated into a portable device to achieve a truly portable, low-cost, local three-dimensional deformation measurement, one-time calibration and easy implementation in situ. The optical design and measurement procedures to obtain the three-dimensional （3D） deformation measurements of the proposed system were described in detail. The efficiency and precision of the proposed system were verified by measuring the displacements of a translated fiat plate. As a practical application, the proposed system is used to measure the out-of-plane displacement of an aluminum circular plate with a central load. Moreover, the normal strain measurement of a plastic beam under symmetric four-point bending via an outer loading frame was also presented. The measurement results are in good accordance with the data obtained by strain gauges. The experimental results revealed that the proposed system was practicable and effective for the local three-dimensional deformation measurement. This system well-suited to both laboratory and field condition and will have significant application in the fields of engineering.

关键词： digital image correlation single camera strain analysis local 3D deformation

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Performance analysis of a hybrid optical CDMA/DWDM system against inter-symbol interference and four wave mixing

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Digital Communications and Networks 2021年第1期7卷 151-156页

作者： Naif Alsowaidi Tawfig Eltaif Mohd Ridzuan mokhtar Faculty of Engineering Technology Multimedia University75450Bukit BeruangMelakaMalaysia School of Engineering University of TasmaniaHobartTasmania7005Australia School of Electrical and Computer Engineering Xiamen University Malaysia43900 SepangSelangorMalaysia Faculty of Engineering Multimedia University63100CyberjayaSelangorMalaysia

This paper reports the implementation and theoretical model for analyzing an optical CDMA/DWDM hybrid system to reduce two major problems,the Inter-Symbol Interference(ISI)and the Four-Wave Mixing(FWM)effects and improve the performance of optical subscriber access networks by using Zero Cross-Correlation(ZCC)optical codes,which helps to reduce the effect of the Multiple Access Interference(MAI).A squeezing method is used in the proposed hybrid system to completely suppress the *** this method,the sequence interval of the signature code is squeezed into a duration of less than *** hybrid system is capable of accommodating 120 optical CDMA users carried by only 10 DWDM wavelengths spaced by 0.2 nm with 60 Gb/s/wavelength transmitted over 105.075 km of optical *** result shows that the optimum interval of the code sequence is a quarter(i.e.,25%)of the bit ***,the results reveal that the CDMA technology based on the spread spectrum is capable of increasing the nonlinear tolerance of the proposed hybrid system as the energy of bits is distributed over the chip sequence ***,the number of ones/weight and the positions between them have a significant effect on the performance of the proposed hybrid system.

关键词： Optical CDMA Dense wavelength division multiplexing Four wave mixing Inter-symbol interference

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Conduction properties of condensed lanthanum phosphates:La(PO_3)_3 and LaP_5O_(14)

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Journal of Rare Earths 2010年第3期28卷 321-328页

作者： Ines Hammas Karima Horchani-Naifer mokhtar Férid Research Unit of Rare Earth Materials National Research Center in Sciences of MaterialsB.P.95 Hammam-Lif2050Tunisia

Single crystals of LaP3O9·3H2O were prepared using a classical method of aqueous chemistry whereas those of the ultraphosphate LaP5O14 were obtained by flux *** treatment of LaP3O9·3H2O up to 700 °C allowed us to obtain the lanthanum polyphosphate La(PO3)*** conductivity as well as the vibrational study of the lanthanum ultraphosphate and polyphosphate were analysed in order to explain the mechanism of *** energies of 0.45 and 0.84 eV,deduced from the Arrhenius relation,were r...

关键词： condensed lanthanum phosphates electrical conductivity Grotthuss mechanism rare earths

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