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Adsorptive removal of iron and manganese ions from aqueous solutions with microporous chitosan/polyethylene glycol blend membrane

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Journal of Environmental Sciences 2012年第8期24卷 1425-1432页

作者： Nea.a.A.Reiad Omar E.Abdel salam.ehab F.a.a.ir Farid A.Harraz Sanitary&Environmental Department Housing&Building National Research Center87 el Tahrir st.DokkiEgypt Department of Chemical Engineering Faculty of EngineeringCairo UniversityGizaEgypt Advanced Materials Technology Department Central Metallurgical R&D InstituteHelwanEgypt

Microporous chitosan （CS） membranes were directly prepared by extraction of poly（ethylene glycol）（PEG） from CS/PEG blend membrane and were examined for iron and manganese ions removal from aqueous solutions. The different variables affecting the adsorption ca.a.ity of the membranes such as contact time, pH of the sorption medium, and initial metal ion concentration in the feed solution were investigated on a batch adsorption basis. The affinity of CS/PEG blend membrane to adsorb Fe（II） ions is higher than that of Mn（II） ions, with adsorption equilibrium achieved after 60 min for Fe（II） and Mn（II） ions. By increasing CS]PEG ratio in the blend membrane the adsorption ca.a.ity of metal ions increased. Among all pa.a.eters, pH has the most significant effect on the adsorption ca.a.ity, particularly in the range of 2.9-5.9. The increase in CS/PEG ratio was found to enhance the adsorption ca.a.ity of the membranes. The effects of initial concentration of metal ions on the extent of metal ions removal were investigated in detail. The experimental da.a.were better fitted to Freundlich equation than Langmuir. In addition, it was found that the iron and manganese ions adsorbed on the membranes can be effectively desorbed in 0.1 mol/L HCl solution （up to 98% desorption efficiency） and the blend membranes can be reused almost without loss of the adsorption ca.a.ity for iron and manganese ions.

关键词： chitosan blend membrane iron and manganese ions adsorption

Metaheuristic Lightweight Cryptography for Security Enhancement in Internet of Things

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Computers, Materials & Continua 2022年第8期72卷 3009-3023页

作者： Mahmoud Ra.a. ehab Ba.a.dien Ashary Information Technology Department Faculty of Computing and Information TechnologyKing Abdulaziz UniversityJeddah21589Saudi Arabia Centre of Artificial Intelligence for Precision Medicines King Abdulaziz UniversityJeddah21589Saudi Arabia Mathematics Department Faculty of ScienceAl-Azhar UniversityNaser City11884CairoEgypt Electrical and Computer Engineering Department Faculty of EngineeringKing Abdulaziz UniversityJeddah21589Saudi Arabia

The advancements made in Internet of Things(IoT)is projected to alter the functioning of healthcare industry in addition to increased penetration of different ***,da.a.security and private are challenging tasks to accomplish in IoT and necessary measures to be taken to ensure secure *** this background,the current paper proposes a novel lightweight cryptography method for enhance the security in *** proposed encryption algorithm is a blend of Cross Correlation Coefficient(CCC)and Black Widow Optimization(BWO)*** the presented encryption technique,CCC operation is utilized to optimize the encryption process of cryptography *** projected encryption algorithm works in line with encryption and decryption *** key selection is performed with the help of Artificial Intelligence(AI)tool named BWO *** the combination of AI technique and CCC operation,optimal security operation is improved in *** different sets of images collected from da.a.ases,the projected technique was validated in MATLAB on the basis of few performance metrics such as encryption time,decryption time,Peak Signal to Noise Ratio(PSNR),CC,Error,encryption time and decryption *** results were compared with existing methods such as Elliptical Curve cryptography(ECC)and Rivest-Shamir-Adleman(RSa.a.d the supremacy of the projected method is established.

关键词： Security images encryption time correlation coefficient black widow optimization artificial intelligence decryption time

Mathematical a.a.yses of the GPS receiver interference tolerance and mean time to loss lock

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Defence Technology（防务技术） 2019年第3期15卷 440-449页

作者： ehab M.Shaheen Sherif A.Elgamel Electronic Warfare Department Military Technical College

In this paper, novel mathematical expressions are derived for the Global Positioning System (GPS) receiver interference tolerance in the presence of different types of interference signals such as: continuous wave interference, narrowband interference, partial band interference, broadband interference, match spectrum interference and pulse interference. Also, in this paper the mean time to loss lock is determined in order to a.a.yse the mentioned interferences effect on the GPS receiver. These derived a.a.ytical expressions are validated with the aid of extensive simulation experiments.

关键词： Mathematical a.a.yses GPS receiver interference tolerance

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 a.a.tive sparsity channel estimation(IASCE). In these techniques, the sparsity of the 1-bit ADC MIMO channel is exploited to propose a new a.a.tive 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

Beamforming techniques for massive MIMO systems in 5G:overview,classification,and trends for future research

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Frontiers of Information Technology & Electronic Engineering 2017年第6期18卷 753-772页

作者： ehab ALI Ma.a.od ISMAIL Rosdiadee NORDIN Nor Fadzilah ABDULAH Department of Electrical Electronic and System EngineeringUniversiti Kebangsaan Malaysia(UKM)Bangi 43600Malaysia

Massive multiple-input multiple-output(MIMO) systems combined with beamforming antenna.a.ray technologies are expected to play a key role in next-generation wireless communication systems(5G), which will be deployed in 2020 and beyond. The main objective of this review paper is to discuss the state-of-the-art research on the most favourable types of beamforming techniques that can be deployed in massive MIMO systems and to clarify the importance of beamforming techniques in massive MIMO systems for eliminating and resolving the many technical hitches that massive MIMO system implementation faces. Classifications of optimal beamforming techniques that are used in wireless communication systems are reviewed in detail to determine which techniques are more suitable for deployment in massive MIMO systems to improve system throughput and reduce intra.a.d inter-cell interference. To overcome the limitations in the literature, we have suggested an optimal beamforming technique that can provide the highest performance in massive MIMO systems, satisfying the requirements of next-generation wireless communication systems.

关键词： Beamforming classifications Massive MIMO Hybrid beamforming Millimetre-wave beamforming

d-EMR:Secure and distributed Electronic Medical Record ma.a.ement

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High-Confidence Computing 2023年第1期3卷 47-57页

作者： ehab Zaghloul Tongtong Li Jian Ren Department of Electrical and Computer Engineering Michigan State UniversityUSA

As more and more da.a.is produced,finding a secure and efficient da.a.access structure has become a major research *** centralized systems used by medical institutions for the ma.a.ement and transfer of Electronic Medical Records(EMRs)can be vulnerable to security and privacy threats,often lack interoperability,and give patients limited or no access to their own *** this paper,we first propose a privilege-based da.a.access structure and incorporates it into an attribute-based encryption mechanism to handle the ma.a.ement and sharing of big da.a.*** proposed privilege-based da.a.access structure makes ma.a.ing healthcare records using mobile healthcare devices efficient and feasible for large numbers of *** then propose a novel distributed multilevel EMR(d-EMR)ma.a.ement scheme,which uses blockchain to address security concerns and enables selective sharing of medical records among staff members that belong to different levels of a hierarchical *** deploy smart contracts on Ethereum blockchain and utilize a distributed storage system to alleviate the dependence on the record-generating institutions to ma.a.e and share patient *** preserve privacy of patient records,our smart contract is designed to allow patients to verify attributes prior to granting access *** provide extensive security,privacy,and evaluation a.a.yses to show that our proposed scheme is both efficient and practical.

关键词： Privilege-based access Hierarchy Attribute-based encryption EMRs Distributed da.a.sharing Blockchain Smart contract

Effects of Plasticizers,Antioxidants and Burning Rate Modifiers on Aging Performance of the HTPB/HMDI Composite Solid Propellant

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含能材料 2019年第1期27卷 21-27,90页

作者： Ahmed M Enew ehab a.a.ir Sa.a. Elmarsafy Karim K Elsharkawy Chemical Department Faculty of EngineeringCairo University School of Chemistry and Environment Beijing University of Aeronautics and Astronautics

The effects of plasticizers,antioxidants and burning rate modifiers on the aging performance of the composite solid propellant based on hydroxyl-terminated polybutadiene(HTPB)/hexamethylene diisocya.a.e(HMDI)were explored by apply-ing an accelerated aging program for 90 day at 70 ℃. The HTPB propellant matrix with the diisooctyl seba.a.e(DOS)as plasti-cizers and diisooctyl azelate(DOZ), antioxidants as N,N ′-Diphenyl-p-phenylenediamine(AO) and 2,2′-methylenebis(4-methyl-6-tert-butylphenol)(cyanox 2246)and burning rate modifiers as barium ferrite(BF),copper chromites(CC)and fer-ric oxide(FO)were varied. Results show that sample(S1)which based on DOS decreases the stress value and increases the strain value which considered to be an excellent start for aging program. Sample(S3)containing AO presents the higher resis-tance to oxidation showing the better performance that reflects on increasing the shelf life of the composite solid propellant mo-tor. Sample(S5)which based on BF enhances the ballistic performance among over the other tested two samples. The accelerat-ed aging program allowed us to estimate the motor in-service lifetime.

关键词： polybutadiene(HTPB)/hexamethylene diisocya.a.e(HMDI)composite solid propellant plasticizers antioxidants burning rate modifiers aging program

Simulation of Water-Soil-Structure Interactions Using Incompressible Smoothed Particle Hydrodynamics

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Computers, Materials & Continua 2020年第10期65卷 205-224页

作者： Abdelraheem M.Aly Mitsuteru a.a. ehab Mahmoud Mohamed Department of Mathematics College of ScienceKing Khalid UniversityAbha62529Saudi Arabia Department of Mathematics Faculty of ScienceSouth Valley UniversityQena83523Egypt Civil Engineering Department Kyushu UniversityFukuoka819-0395Japan Electrical Engineering Department College of EngineeringPrince Sattam Bin Abdulaziz UniversityWadi Addwasir11991Saudi Arabia Electrical Engineering Department Faculty of EngineeringAswan UniversityAswan81542Egypt

In the present work,an incompressible smoothed particle hydrodynamic(SPH)method is introduced to simulate water-soil-structure *** the current calculation,the water is modelled as a Newtonian *** soil is modelled in two different *** the first case,the granular material is considered as a fluid where a Bingham type constitutive model is proposed based on Mohr-Coulomb yield-stress criterion,and the viscosity is derived from the cohesion and friction *** addition,the fictitious suspension layers between water and soil depending on the concentration of soil are *** the second case,Hooke’s law introduces elastic *** ISPH,the pressure is evaluated by solving the pressure Poisson equation using a semi-implicit algorithm based on the projection method and an eddy viscosity for water is modelled by a large eddy simulation with the Smagorinsky *** the proposed ISPH method,the pressure is stabilized to simulate the multiphase flow between soil and *** experiments for water-soil suspension flow of Louvain erosional dam break with flat soil foundation,is simulated and validated using 3D-ISPH *** between water-soil interactions with different solid structures are *** results revealed that,the suspension layers with the Bingham model of soil gives more accurate results in the experiment as compared to the case of the Bingham model without suspension *** addition,the elastic soil model by the Hooke’s law can simulate soil hump accurately as compared to the Bingham *** the simulations,avoiding erosion behind the structure for preventing the structure break during flood are investigated by using an extended structure or a wedge structure.

关键词： Bingham model ISPH method rigid body water-soil interactions

Outcomes of pancreaticoduodenectomy in elderly patients

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Hepatobiliary & Pancreatic Diseases International 2016年第4期15卷 419-427页

作者： Ayman El Nakeeb ehab Atef ehab El Ha.a.y Ali Salem Waleed Askar Helmy Ezzat Ahmed Shehta Mohamed Abdel Wa.a. Gastroenterology Surgical Center Mansoura University

BACKGROUND： Although the mortality and morbidity of pancreaticoduodenectomy（PD） have improved significantly over the past years, the concerns for elderly patients undergoing PD are still present. Furthermore, the frequency of PD is increasing because of the increasing proportion of elderly patients and the increasing incidence of periampullary tumors. This study aimed to a.a.yze the outcomes of PD in elderly ***： We studied all patients who had undergone PD in our center between January 1995 and February 2015. The patients were divided into three groups based on age： group I（patients aged 〈60 years）, group II（those aged 60 to 69 years） and group III（those aged ≥70 years）. The primary outcome was the rate of total postoperative complications. Secondary endpoint included total operative time, hospital mortality, length of postoperative hospital stay, delayed gastric emptying, re-exploration, and survival ***： A total of 828 patients who had undergone PD for resection of periampullary tumor were included in this study. There were 579（69.9%） patients in group I, 201（24.3%） in group II, and 48（5.8%） in group III. The overall incidence of complications was higher in elderly patients（25.9% in group I, 36.8% in group II, and 37.5% in group III; P=0.006）. There were more patients complicated with delayed gastric emptying in group II compared with the other two groups. There was no significant difference in the incidence of postoperative pancreatic fistula, biliary lea.a.e, pancreatitis, pulmonary complications and hospital ***： PD can be performed safely in selected elderly patients. Advanced age alone should not be a contraindication for PD. The outcome of elderly patients who have undergone PD is similar to that of younger patients, and the increased rate of complications is due to the presence of associated comorbidities.

关键词： pancreaticoduodenectomy elderly pancreatic fistula delayed gastric emptying