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A coal rib monitoring study in a room-and-pillar retreat mine

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International Journal of Mining Science and Technology 2021年第1期31卷 127-135页

作者： gamal Rashed Khaled Mohamed Robert Kimutis gCB/PMRD//NIOSH/CDC PittsburghPA 15236USA

The National Institute for Occupational Safety and Health(NIOSH)conducted a comprehensive monitoring program in a room-and-pillar mine located in Southern *** deformation and the stress change in an instrumented pillar were monitored during the progress of pillar retreat mining at two sites of different geological conditions and depths of *** main objectives of the monitoring program were to better understand the stress transfer and load shedding on coal pillars and to quantify the rib deformation due to pillar retreat mining;and to examine the effect of rib geology and overburden depth on coal rib *** instrumentation at both sites included pull-out tests to measure the anchorage capacity of rib bolts,load cells mounted on rib bolts to monitor the induced loads in the bolts,borehole pressure cells(BPCs)installed at various depths in the study pillar to measure the change in vertical pressure within the pillar,and roof and rib extensometers installed to quantify the vertical displacement of the roof and the horizontal displacement of the rib that would occur during the retreat mining *** outcome from the monitoring program provides insight into coal pillar rib support optimization at various depths and geological ***,this study contributes to the NIOSH rib support database in U.S coal mines and provides essential data for rib support design.

关键词： Coal rib performance Coal rib design Coal rib monitoring Coal rib failure load transfer Retreat mining

Effects of γ-irradiation and Deformation Temperature on Tensile Properties of Pb-2 mass% Sb Alloy

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Journal of Iron and Steel Research International 2016年第7期23卷 733-738页

作者： gh MOHAMMED S.EI-gamal Physics Department Faculty of ScienceNorthern Borders University Physics Department Faculty of EducationAin Shams University

Effects ofγ-irradiation and deformation temperature（T）on the tensile properties of Pb-2mass% Sb alloys were *** samples were annealed at 458 Kfor 2hin air,then water quenched after they wereγ-irradiated（the different doses were 0.5,1.0,1.5,and 2.0 Mgy）.The tensile properties were performed using stress-strain measurements at a constant strain rate（1.2×10^（-3） s^（-1））and at different T（303-393K）.It was found that at constant dose,the fracture stress（σF）decreases while the fracture strain（εF）increases as *** particular T,σFincreases whileεFdecreases with increasing *** strain-hardening exponent（n）,which is the slope of the relation between ln（σ）and ln（ε）of the parabolic part of the stress-strain curve,was determined and its values increase as Tincreases and decrease as the dose *** value of the activation energy increases as the dose increases from 0.07 eV for un-irradiated sample to 0.1eV for the 2 Mgy-irradiated *** values are in accordance with that needed for dislocation movement and ordering *** interpretation of the results was given,based on the creation of point and line defects due toγ-irradiation,and that results in a distribution of beta phase（Sb-phase）,leading to a difficulty in the movement of dislocations,so there is an increase in alloy hardness.

关键词： γ-irradiation deformation temperature tensile property Pb-2 mass% Sb alloy

loading characteristics of mechanical rib bolts determined through testing and numerical modeling

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International Journal of Mining Science and Technology 2020年第1期30卷 17-24页

作者： Khaled Mohamed gamal Rashed Zorica Radakovic-guzina Centers for Disease Control National Institute for Occupational Safety and HealthPittsburghPA 15236USA ITASCA Consulting group MinneapolisMN 55401USA

Underground coal mines use mechanical bolts in addition to other types of bolts to control the rib deformation and to stabilize the yielded coal *** research has been conducted to understand the performance of the mechanical bolts in coal *** from the National Institute for Occupational Safety and Health(NIOSH)conducted this work to understand the loading characteristics of mechanical bolts(stiffness and capacity)installed in coal ribs at five underground coal *** pull-out tests were performed in this study to define the loading characteristics of mechanical rib *** installation torques were applied to the tested bolts based on the strength of the coal seam.A typical tri-linear load-deformation response for mechanical bolts was obtained from these *** was found that the anchorage capacity depended mainly on the coal *** for modeling mechanical bolts have been developed using the tri-linear load-deformation *** outcome of this research provides essential data for rib support design.

关键词： Coal rib Mechanical bolt Conventional bolt Tension bolt Point-anchored bolt Rib support Pull-out test Numerical modeling FlAC3D

Double compound combination synchronization among eight n-dimensional chaotic systems

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Chinese Physics B 2018年第8期27卷 150-158页

作者： gamal M Mahmoud Tarek M Abed-Elhameed Ahmed A Farghaly Department of Mathematics Faculty of Science Assiut University

Depending on double compound synchronization and compound combination synchronization, a new kind of syn- chronization is introduced which is the double compound combination synchronization （DCCS） of eight n-dimensional chaotic systems. This kind may be considered as a generalization of many types of synchronization. In the communica- tion, based on many of drive and response systems, the transmitted and received signals will be more secure. Using the lyapunov stability theory and nonlinear feedback control, analytical formulas of control functions are obtained to insure our results. The corresponding analytical expression and numerical treatment are used to show the validity and feasibility of our proposed synchronization scheme. The eight memristor-based Chua oscillators are considered as an example. Other examples can be similarly investigated. The proposed synchronization technique is supported using the MATlAB simula- tion outcomes. We obtain the same results of numerical treatment of our synchronization using simulation observations of our example.

关键词： double compound synchronization compound combination synchronization chaotic system lya-punov stability

Video Identification Based on Watermarking Schemes and Visual Cryptography

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Computer Systems Science & Engineering 2022年第2期40卷 441-453页

作者： Maged Wafy Samr gamal Zanaty Mahmoud Elkhouly Department of Information Technology Computers and Artificial Intelligence Helwan UniversityCairoEgypt Department of Information Technology Computing Studies Arab Open UniversityCairoEgypt Department of Information Technology Information Technology and Computer Science Sinai UniversityIsmailiaEgypt

Related to the growth of data sharing on the Internet and the wide-spread use of digital media,multimedia security and copyright protection have become of broad *** cryptography(VC)is a method of sharing a secret image between a group of participants,where certain groups of participants are defined as qualified and may combine their share of the image to obtain the original,and certain other groups are defined as prohibited,and even if they combine knowledge of their parts,they can’t obtain any information on the secret *** visual cryptography is one of the techniques which used to transmit the secrete image under the cover *** vision systems are connected to visual *** black and white image was originally used as a hidden *** order to achieve the owner’s copy right security based on visual cryptography,a watermarking algorithm is *** suggest an approach in this paper to hide multiple images in video by meaningful shares using one binary *** a common share,which we refer to as a smart key,we can decrypt several images *** on a given share,the smart key decrypts several hidden *** smart key is printed on transparency and the shares are involved in video and decryption is performed by physically superimposing the transparency on the *** binary,grayscale,and color images,we test the proposed method.

关键词： Visual cryptography(VC) video watermarking PSNR

A new systematic firefly algorithm for forecasting the durability of reinforced recycled aggregate concrete

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Frontiers of Structural and Civil Engineering 2022年第3期16卷 329-346页

作者： Wafaa Mohamed SHABAN Khalid ElBAZ Mohamed AMIN Ayat gamal ASHOUR Department of Civil and Environmental Engineering College of EngineeringShantou UniversityShantou 515063China Department of Civil Engineering Misr Higher Institute of Engineering and TechnologyMansouraEgypt Department of Civil Engineering Higher Future Institute of Engineering and TechnologyMansouraEgypt guangdong Engineering Center for Structure Safety and Health Monitoring Shantou UniversityShantou 515063China Civil and Architectural Construction Department Faculty of Technology and EducationSuez UniversityIsmailiaEgypt Department of Civil and Environmental Engineering Collage of EngineeringUniversity of SharjahSharjah 27272UAE

This study presents a new systematic algorithm to optimize the durability of reinforced recycled aggregate *** proposed algorithm integrates machine learning with a new version of the firefly algorithm called chaotic based firefly algorithm(CFA)to evolve a rational and efficient predictive *** CFA optimizer is augmented with chaotic maps and levy flight to improve the firefly performance in forecasting the chloride penetrability of strengthened recycled aggregate concrete(RAC).A comprehensive and credible database of distinctive chloride migration coefficient results is used to establish the developed algorithm.A dataset composite of nine effective parameters,including concrete components and fundamental characteristics of recycled aggregate(RA),is used as input to predict the migration coefficient of strengthened RAC as output,k-fold cross validation algorithm is utilized to validate the hybrid *** numerical benchmark analyses are applied to prove the superiority and applicability of the CFA algorithm in predicting chloride *** show that the developed CFA approach significantly outperforms the firefly algorithm on almost tested functions and demonstrates powerful *** addition,the proposed strategy can be an active tool to recognize the contradictions in the experimental results and can be especially beneficial for assessing the chloride resistance of RAC.

关键词： chloride penetrability recycled aggregate concrete machine learning concrete components durability

Iron Biomineralization Controls on geophysical Signatures of Hydrocarbon Contaminated Sediments

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Journal of Earth Science 2015年第6期26卷 835-843页

作者： Estella A.Atekwana gamal Z.Abdel Aal Boone Pickens School of geology Oklahoma State University geology Department Faculty of Science Assiut University

The interpretation of geophysical data from mature hydrocarbon contaminated sites has relied on a conductive plume model where the conductivity of the subsurface contaminant volume is the result of microbial mediated changes in pore fluid chemistry. This conductive anomalous region is characterized by high total dissolved solids and occurs within the water table fluctuation zone where microbial activity is the maximum. Here we update this conductive plume model by providing new insights from recent laboratory investigations and geophysical data from hydrocarbon contaminated sites suggesting the unrecognized role of the impact that microbial-mediated metallic mineral precipitates have on geophysical signatures. We show that microbial redox processes（e.g., iron and sulfate reduction） during the biodegradation process involve mineralogical transformations and the precipitation of new minerals（e.g., magnetite, and pyrite） that can impact the electrical and magnetic properties of contaminated sediments. We provide examples from laboratory experiments and field studies and suggest that knowledge of the dominant redox processes occurring at hydrocarbon contaminated sites and the mineral phases formed is critical for a more robust interpretation of geophysical data associated with microbial-mediated changes at hydrocarbon contaminated sites. We also show that integration of both magnetic and electrical techniques may help reduce ambiguity in data interpretation.

关键词： hydrocarbon redox processes magnetic susceptibility bioremediation conductivity.

Non-alcoholic steatohepatitis or metabolic-associated fatty liver:time to change

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Hepatobiliary Surgery and Nutrition 2021年第1期10卷 123-125页

作者： gamal Shiha Nasser Mousa Egyptian liver Research Institute and Hospital(ElRIAH) MansouraEgypt Hepatology and gastroenterology Unit Internal Medicine Department Tropical Medicine Department Faculty of MedicineMansoura UniversityMansouraEgypt

Non-alcoholic fatty liver disease(NAFlD)is a range of liver disease characterized by the occurrence of steatosis in greater than 5%of hepatocytes of people who drink tiny or no *** comprises,a benign non-alcoholic fatty liver(NAFl),and the more serious non-alcoholic steatohepatitis(NASH)described by steatosis,hepatocellular ballooning,lobular inflammation and lastly cirrhosis(1).

关键词： balloon NAFlD liver

Characteristic properties of date-palm fibre/sheep wool reinforced polyester composites

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Journal of Bioresources and Bioproducts 2023年第4期8卷 430-443页

作者： Mohammed Y.Abdellah Mustafa gamal Sadek Hamzah Alharthi g.T.Abdel-Jaber Ahmed H.Backar Mechanical Engineering Department Faculty of EngineeringSouth Valley UniversityQena83523Egypt Mechanical Engineering Department College of Engineering and Islamic ArchitectureUmm AL-Qura UniversityMakkah21955Saudi Arabia New Assiut Technological University(NAUT) Assiut71684Egypt Production Engineering Department Faculty of EngineeringAlexandria UniversityAlexandria21544Egypt

In this study,we attempted to characterise the effects of date-palm fibre(DPF)and a date-palm fibre/sheep wool hybrid in polyester to enhance high-performance and low-cost composite materials that can be used in insulation building systems,automotive parts,and home *** DPF was treated using 5%NaOH solution;and the sheep wool was cleaned with 50℃hot water and *** composite specimens were prepared with different fibre contents(0%,10%,20%,30%(w))using a compression moulding *** effect of fibre reinforcement was analysed in terms of the mechanical properties(tensile,flexural,impact,and hardness)and composite ***,scanning electron microscopy(SEM)was performed on the fibres before and after treatment,and the fractured surfaces of all composite specimens were examined after tensile *** results showed that the 20%DPF/sheep wool hybrid reinforced polyester produced the best *** ultimate tensile strength and modulus were 27 MPa and 3.69gPa,*** ultimate flexural strength and flexural modulus were 35.4 and 2507 MPa,*** impact strength was 39.5 kJ/m^(2)and the hardness was 64 *** density decreased to the lowest value of 1.02 g/cm^(3)with the 30%DPF/sheep wool *** SEM showed good adhesion and interfacial bonding between DPF/sheep wool hybrid fibres and the polyester matrix,particularly at 20%fibre content.

关键词： Date-palm fibre Polyester Compression moulding Mechanical property