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Development of AZ91/siC surface composite by FsP:effect of vibration and process parameters on microstructure and mechanical characteristics

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Advances in Manufacturing 2020年第1期8卷 82-96页

作者： Behrouz Bagheri mahmoud Abbasi Department of Mining and Metallurgy Amirkabir University of TechnologyTehranIran Faculty of Engineering University of Kashan.KashanIran

A surface composite layer enhances the mechanical characteristics of a surface while retaining the properties of the base *** stir processing(FsP)is a method for forming surface metal matrix composites(sMMCs)that reinforce a surface with *** the current study,a new method entitled friction stir vibration processing(FsVP)was applied to form sMMCs on the surface of AZ91 magnesium alloy with siC particles as the reinforcing *** to FsP,in FsVP,the workpiece was vibrated normal to the processing line while the tool rotated and *** microstructure and mechanical properties of friction stir(Fs)and friction stir vibration(FsV)processed specimens were ***,the effects of vibration frequency and process parameters on different characteristics of Fs and FsV processed specimens were *** results showed that the stir zone grains for FsV processed specimens were finer than those for Fs processed specimens,and the second phase particles(siC particles)had a more homogenous distribution in the former specimens than in the latter *** was related to the effect of workpiece vibration during FsVP,which increased the material deformation and led to enhanced dynamic recrystallization and the breakdown of agglomerated siC *** results indicated that the stir zone grain size decreased,and the distribution homogeneity of the siC particles increased as vibration frequency *** was also observed that the stir zone grain size increased,and the mechanical properties of the processed specimens decreased as tool rotation speed increased.

关键词： Friction stir processing(FsP) Vibration AZ91 magnesium alloy Dynamic recrystallization Microstructure Mechanical properties

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A spatiotemporal algebra in Hadoop for moving objects

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Geo-spatial Information science 2018年第2期21卷 102-114页

作者： Mohamed s.Bakli mahmoud A.sakr Taysir Hassan A.soliman Faculty of Computers and Information Assiut UniversityAssiutEgypt Faculty of Computer and Information sciences Ain Shams UniversityCairoEgypt Universitélibre de Bruxelles BruxellesBelgium

spatiotemporal data represent the real-world objects that move in geographic space over *** enormous numbers of mobile sensors and location tracking devices continuously produce massive amounts of such *** leads to the need for scalable spatiotemporal data management *** systems shall be capable of representing spatiotemporal data in persistent storage and in *** shall also provide a range of query processing operators that may scale out in a cloud ***,very few researches have been conducted to meet this *** paper proposes a Hadoop extension with a spatiotemporal *** algebra consists of moving object types added as Hadoop native types,and operators on top of *** Hadoop file system has been extended to support parameter passing for files that contain spatiotemporal data,and for operators that can be unary or *** the types and operators are accessible for the MapReduce *** an extension allows users to write Hadoop programs that can perform spatiotemporal *** queries may call more than one operator for different jobs and keep these operators running in *** paper describes the design and implementation of this algebra,and evaluates it using a benchmark that is specific to moving object databases.

关键词： spatiotemporal algebra Hadoop MapReduce moving objects

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Unveiling the complexities of microbiologically induced corrosion:mechanisms,detection techniques,and mitigation strategies

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Frontiers of Environmental science & Engineering 2024年第10期18卷 15-48页

作者： mahmoud A.Ahmed safwat A.mahmoud Ashraf A.Mohamed Veolia Water Technologies Cairo 11835Egypt Chemistry department Faculty of ScienceAin Shams UniversityCairo 11566Egypt Physics Department Faculty of ScienceNorthern Border UniversityArar 13211Saudi Arabia

Microbiologically induced corrosion(MIC)is a complex and destructive phenomenon that occurs in various sectors,involving the interaction between microorganisms and metal surfaces,resulting in accelerated corrosion *** review article provides a comprehensive analysis of MIC,encompassing microbial species involved,their metabolic activities,and influential environmental factors driving the corrosion *** mechanisms of MIC,both in the presence and absence of oxygen,are explored,along with the diverse effects of microbes on different types of corrosion and their economic *** and monitoring techniques,including traditional and advanced methods such as microbiological and electrochemical methods,are ***,it examines preventive and control measures,such as the use of biocides and their mechanisms of *** to enhance the performance of these control measures and the effectiveness of antimicrobial agents during disinfection processes,including surfactants and chelators,are ***,the review highlights enzymatic remediation as a sustainable alternative approach,providing detailed *** challenges in mitigating MIC and potential future developments and collaborative opportunities are also *** systematic review is a valuable resource for researchers,industry professionals,and policymakers seeking a comprehensive understanding of the complex phenomenon of MIC and effective strategies for its management.

关键词： Metal failure Biofilm formation Enzymatic remediation Antimicrobial agents Bio-corrosion mechanisms

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Efficient AUV Path Planning in Time-Variant Underwater Environment Using Differential Evolution Algorithm

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Journal of Marine science and Application 2018年第4期17卷 585-591页

作者： s.mahmoud Zadeh D.M.W Powers A.M.Yazdani K.sammut A.Atyabi school of Computer science Engineering and Mathematics Flinders University Tonsley Centre for Maritime Engineering Control and Imaging Flinders University seattle Children's Research Institute University of Washington

Robust and efficient AUV path planning is a key element for persistence AUV maneuvering in variable underwater environments. To develop such a path planning system, in this study, differential evolution(DE) algorithm is employed. The performance of the DE-based planner in generating time-efficient paths to direct the AUV from its initial conditions to the target of interest is investigated within a complexed 3D underwater environment incorporated with turbulent current vector fields, coastal area,islands, and static/dynamic obstacles. The results of simulations indicate the inherent efficiency of the DE-based path planner as it is capable of extracting feasible areas of a real map to determine the allowed spaces for the vehicle deployment while coping undesired current disturbances, exploiting desirable currents, and avoiding collision boundaries in directing the vehicle to its destination. The results are implementable for a realistic scenario and on-board real AUV as the DE planner satisfies all vehicular and environmental constraints while minimizing the travel time/distance, in a computationally efficient manner.

关键词： Path planning Differential evolution Autonomous underwater vehicles Evolutionary algorithms Obstacle avoidance

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Variant Wasserstein Generative Adversarial Network Applied on Low Dose CT Image Denoising

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Computers, Materials & Continua 2023年第5期75卷 4535-4552页

作者： Anoud A.mahmoud Hanaa A.sayed sara s.Mohamed Department of Mathematics and Computer science Faculty of ScienceNew Valley UniversityNew Valley72511Egypt Department of Computer science College of Computer Science and Engineering Taibah UniversityMedina42221KSA Department of Mathematics Faculty of ScienceAssiut UniversityAssiut71516Egypt

Computed Tomography(CT)images have been extensively employed in disease diagnosis and treatment,causing a huge concern over the dose of radiation to which patients are *** the radiation dose to get a better image may lead to the development of genetic disorders and cancer in the patients;on the other hand,decreasing it by using a Low-Dose CT(LDCT)image may cause more noise and increased artifacts,which can compromise the ***,image reconstruction from LDCT image data is necessary to improve radiologists’judgment and *** study proposed three novel models for denoising LDCT images based on Wasserstein Generative Adversarial Network(WGAN).They were incorporated with different loss functions,including Visual Geometry Group(VGG),structural similarity Loss(ssIM),and structurally sensitive Loss(ssL),to reduce noise and preserve important information on LDCT images and investigate the effect of different types of loss ***,experiments have been conducted on the Graphical Processing Unit(GPU)and Central Processing Unit(CPU)to compare the performance of the proposed *** results demonstrated that images from the proposed WGAN-ssIM,WGAN-VGG-ssIM,and WGAN-VGG-ssL were denoised better than those from state-of-the-art models(WGAN,WGAN-VGG,and sMGAN)and converged to a stable equilibrium compared with WGAN and *** proposed models are effective in reducing noise,suppressing artifacts,and maintaining informative structure and texture details,especially WGAN-VGG-ssL which achieved a high peak-signalto-noise ratio(PNsR)on both GPU(26.1336)and CPU(25.8270).The average accuracy of WGAN-VGG-ssL outperformed that of the state-ofthe-art methods by 1 *** prove that theWGAN-VGG-ssL is more stable than the other models on both GPU and CPU.

关键词： Machine learning deep learning image denoising low dose CT loss function

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A machine vision-intelligent modelling based technique for in-line bell pepper sorting

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Information Processing in Agriculture 2023年第4期10卷 491-503页

作者： Khaled Mohi-Alden mahmoud Omid mahmoud soltani Firouz Amin Nasiri Department of Agricultural Machinery Engineering Faculty of Agricultural Engineering and TechnologyUniversity of TehranIran Department of Biosystems Engineering and soil science University of TennesseeKnoxvilleTN 37996USA

The uniformity of appearance attributes of bell peppers is significant for consumers and food *** automate the sorting process of bell peppers and improve the packaging quality of this crop by detecting and separating the not likable low-color bell peppers,developing an appropriate sorting system would be of high importance and *** to standards and export needs,the bell pepper should be graded based on maturity levels and size to five *** research has been aimed to develop a machine vision-based system equipped with an intelligent modelling approach for in-line sorting bell peppers into desirable and undesirable samples,with the ability to predict the maturity level and the size of the desirable bell *** perceptron(MLP)artificial neural networks(ANNs)as the nonlinear modelswere designed for that *** modelswere trained and evaluated through five-fold cross-validation *** optimum MLP classifier was compared with a linear discriminant analysis(LDA)*** results showed that the MLP outperforms the LDA *** processing time to classify each captured image was estimated as 0.2 s/sample,which is fast enough for in-line ***,the optimum MLP model was integrated with a machine vision-based sorting machine,and the developed system was evaluated in the in-line *** performance parameters,including accuracy,precision,sensitivity,and specificity,were 93.2%,86.4%,84%,and 95.7%,*** total sorting rate of the bell pepper was also measured as approximately 3000 samples/h.

关键词： Bell pepper sorting Image processing Machine vision Multilayer perceptron Linear discriminant analysis

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Anthropogenic mineral generation and its potential resource supply:The case of niobium

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science China Earth sciences 2024年第8期67卷 2583-2591页

作者： Xianlai ZENG Moisés Gómez mahmoud BAKRY Yong GENG Jinhui LI school of Environment Tsinghua UniversityBeijing 100084China school of Environmental science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China school of International and Public Affairs Shanghai Jiao Tong UniversityShanghai 200030China

The strategy of carbon neutrality is reshaping the global landscape of resource flow and *** the final sink of geological minerals,the proliferated anthropogenic minerals,also called secondary resources,play an increasingly important role in resource supply *** is a critical metal that lacks full concern for its *** fundamental principle of niobium circularity is to recycle and maintain the material as close to the manufacturing process as *** we estimate the niobium-containing applications lost at their end-of-life,underscoring the imperative to minimize such ***,we elucidate the extraction processes for scrap and alloy quantities throughout the industry's *** from anticipated waste generated by the majority of niobium applications,a forecast indicates a potential loss of approximately 168 kt by 2090 in the absence of ***,with a recycling efficiency of 90%for niobium,the projected loss diminishes to approximately 16 *** delve into the significance of niobium's circular economy and explore various aspects that demand further investigation for a seamless transition from linear to circular practices.

关键词： Niobium Anthropogenic mineral Circular economy Recycling sustainability

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Efficient Channel Estimation Techniques for MIMO systems with 1-Bit ADC

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China Communications 2020年第5期17卷 50-64页

作者： Hany sHussein shaimaa Hussein Ehab mahmoud Mohamed Electrical Engineering Dept. College of EngineeringKing Khalid UniversityAbha 61411King of Saudi Arabia Electrical Engineering Dept. Faculty of EngineeringAswan UniversityAswan 81542Egypt Electrical Engineering Dept. College of EngineeringPrince Sattam Bin Abdulaziz UniversityWadi Addwasir 11991King of Saudi Arabia

With a low resolution 1-bit ADC on its receiver(RX) side, MIMO with 1-bit ADC took a considerable step in the fulfillment of the hardware complexity constrains of the internet of things(IoT) PHY layer design. However, applying 1-bit ADC at MIMO RX results in severe nonlinear quantization error. By which, almost all received signal amplitude information is completely distorted. Thus, MIMO channel estimation is considered as a major barrier towards practical realization of 1-bit ADC MIMO system. In this paper, two efficient sparsity-based channel estimation techniques are proposed for 1-bit ADC MIMO systems, namely the low complexity sparsity-based channel estimation(LCsCE), and the iterative adaptive sparsity channel estimation(IAsCE). In these techniques, the sparsity of the 1-bit ADC MIMO channel is exploited to propose a new adaptive and iterative compressive sensing(Cs) recovery algorithm to handle the 1-bit ADC quantization effect. The proposed algorithms are tested with the state-of-the-art 1-bit ADC MIMO constant envelope modulation(MIMO-CEM). The 1-bit ADC MIMO-CEM system is chosen as it fulfills both energy and hardware complexity constraints of the IoT PHY layer. simulation results reveal the high effectiveness of the proposed algorithms in terms of spectral efficiency(sE) and computational complexity. The proposed LCsCE reduces the computational complexity of the 1-bit ADC MIMO-CEM channel estimation by 86%, while the IAsCE reduces it by 96% compared to the recent techniques of MIMO-CEM channel estimation. Moreover, the proposed LCsCE and IAsCE improve the spectrum efficiency by 76 % and 73 %, respectively, compared to the recent techniques.

关键词： channel estimation 1-bit ADC MIMO sparsity recovery compressive sensing Internet of things

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Novel synthesis of some Phthalazinone Derivatives

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Chinese Journal of Chemistry 2011年第7期29卷 1446-1450页

作者： mahmoud, mahmoud R. Abou-Elmagd, Wael s.I. Derbala, Hamed A. Hekal, Mohamed H. Chemistry Department Faculty of Science Ain Shams University Abassia 11566 Cairo Egypt

Dimethyl homophthalate condensed with isatin to give the unexpected five membered lactone 3 rather than the half ester 1 and the β-lactone 2. Treatment of compound 3 with excess hydrazine hydrate afforded phthalazinone carbohydrazide 4 which represents a novel method for the synthesis of phthalazinone derivatives. The carhohy- drazide 4 upon treatment with carbon disulphide afforded 1,3,4-oxadiazole derivative 5, which reacted with ethyl- chloroacetate to give the s-alkylated product 6. The structure of compound 3 compared with 2 was discussed using hyperchem professional （7） AM1 calculations, X-ray single crystal structure and complete spectral data.

关键词： phthalazinone carbohydrazide oxadiazole triazolo oxadiazole AMx calculation condensation

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Theoretical work on magnetocaloric effect in La_(0.75)Ca_(0.25)MnO_(3)

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Journal of Advanced Ceramics 2012年第4期1卷 290-295页

作者： mahmoud Aly HAMAD Physics Department College of ScienceAl-Jouf UniversityAl-JoufSkakaP.O.Box 2014Saudi Arabia

In this work,a phenomenological model is applied to describe the magnetocaloric effect for the La_(0.75)Ca_(0.25)MnO_(3)system near a second-order phase transition from a ferromagnetic to a paramagnetic *** on this model,it can predict the values of the magnetocaloric properties from calculation of magnetization as a function of temperature under different external magnetic *** magnetic entropy change reaches a peak of about 5.39 J/(kg·K)at 257 K upon 4 T applied field ***ΔsM distribution is much more uniform than that of gadolinium,which is desirable for an Ericson-cycle magnetic refrigerator.

关键词： magnetocaloric effect model magnetic entropy change heat capacity change relative cooling power

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