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Experimental and mathematical modeling of Cr(Ⅵ) removal using nano-magnetic Fe3O4-coated perlite from the liquid phase

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Chinese Journal of Chemical Engineering 2020年第6期28卷 1582-1590页

作者： Ismail m.Ahmed mostafa m.hamed Sayed S.metwally Chemistry Department College of ScienceJouf UniversitySkakaSaudi Arabia Hot Laboratories and Waste management Center Atomic Energy Authority13759 CairoEgypt

modification of perlite using nano-magnetic iron oxide was implemented to produce nano-magneticFe3O4-coated perlite composite(Fe3O4/Perlite).The prepared composite was characterized using Scanning Electron microscopy,Fourier-Transform Infrared spectroscopy and Powder X-ray *** potentiality of both perlite and Fe3O4/Perlite composite to eliminate Cr(VI)from the environmentally relevant water was *** influence of main factors which could affect the adsorption was studied including;pH of medium,shaking time and Cr(VI)ions *** experimental outcome demonstrated that the modification of perlite by nano-magnetic Fe3O4 showed a significantly enhanced Cr(VI)removal efficiency relative to that of unmodified *** the kinetic studies,the experimental data fitted well with the pseudo-second-order ***,it proposes that Langmuir isotherm is more adequate than the Freundlich isotherm for both perlite and modified *** results recommended that Fe3O4/Perlite composite had a great potential as an economic and efficient adsorbent of Cr(VI)from contaminated water,which has huge application potential.

关键词： Nano-magnetic Composite Kinetics Isotherm Perlite Adsorption

Utilization of iron oxide bearing pellets waste for preparing hard and soft ferromagnetic glass ceramics

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Journal of Advanced Ceramics 2014年第4期3卷 259-268页

作者： Salwa A.m.ABDEL-HAmEED Ibrahim m.hamed Nehal A.ERFAN Glass Research Department National Research CenterDokkiCairoEgypt Chemical Engineering Department Faculty of EngineeringMinia UniversityMiniaEgyp

About 8%of the imported iron oxide pellets burdens to Egypt are *** this paper,broken pellets waste(BPW)is used as raw material for the preparation of hard magnetic glass ceramics(HmGC)as well as soft magnetic glass ceramics(SmGC).About 54 wt%and 37 wt%of BPW are used to prepare SmGC and HmGC,*** thermal analysis(DTA)reveals two broad exothermic peaks for HmGC at 591℃and 697℃,whereas one exothermic peak at 820℃is detected for SmGC.X-ray diffraction(XRD)shows the crystallization of hematite as the sol phase in BPW,and meanwhile,Zn-ferrite and Ba-hexaferrite are identified in SmGC and HmGC,*** electron microscopy(TEm)reveals the crystallization of nanosize particles of~20 nm for SmGC and~12 nm for *** scanning magnetometer(VSm)reveals an increase in saturation magnetization from~1 emu/g for BPW to~77 emu/g for SmGC and 21 emu/g for HmGC.

关键词： magnetic materials nanostructure pellets waste

Introducing a proper hydrogen liquefaction concept for using wasted heat of thermal power plants-case study: Parand gas power plant

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Chinese Journal of Chemical Engineering 2021年第12期34卷 187-196页

作者： hamed Rezaie Azizabadi masoud Ziabasharhagh mostafa mafi Faculty of mechanical Engineering K.N.Toosi University of TechnologyTehranIran Department of mechanical Engineering Imam Khomeini International UniversityQazvinIran

A hydrogen liquefaction concept with an innovative configuration and a capacity of 4 kg·s^(-1)(345.6 t·d^(-1))is *** concept involves an ammonia absorption refrigeration system for the pre-cooling of hydrogen and mR streams from 25℃ to-30℃.The ammonia absorption refrigeration system is fed by exhaust gases of the Pa rand gas power plant that are normally dissipated to the environment with a temperature of 546℃.The simulation is performed by Aspen HYSYS V9.0,using two separate equations of state for simulating hydrogen and mR streams to gain more accurate results especially for ortho-para *** show that conversion enthalpy estimated by Aspen HYSYS,fits very well to the experimental *** the important independent variables and composition of mRs are done using trial and error procedure,a functional and straightforward method for complicated *** minimum temperature limit in the cooling section is lowered,and an ortho-para converter is implemented in this *** proposed concept performs well from energy aspects and leads to COP and SEC equal to 0.271 and 4.54 kW·h·kg^(-1),*** main advantage of this study is in the low SEC,eliminating the losses of the distribution network,and improving the ability of the hydrogen liquefaction for energy storage in off-peak times.

关键词： Hydrogen Liquefaction Absorption refrigeration Waste treatment mixed-refrigerant Ortho-para conversion

Correlation between microstructural features and tensile strength for friction welded joints of AA-7005 aluminum alloy

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Journal of Central South University 2016年第8期23卷 1839-1846页

作者： Seyyed mostafa Tahsini Ayyub Halvaee hamed Khosravi School of metallurgy and materials Engineering College of Engineering University of Tehran Department of materials Engineering Faculty of Engineering University of Sistan and Baluchestan

Similar friction welded joints of AA-7005 aluminum rods were fabricated using different combinations of process parameters such as friction pressure(1.0, 1.5 and 2.0 mPa) and friction time(10, 15 and 20 s). Interfacial microstructure and formation of intermetallic compounds at the joint interface were evaluated via scanning electron microscopy(SEm) equipped with energy dispersive spectrum(EDS), and optical microscopy(Om). microstructural observations reveal the formation of intermetallic phases during the welding process which cannot be extruded from the interface. Theses phases influence the tensile strength of the resultant joints. From the tensile characteristics viewpoint, the greatest tensile strength value of 365 mPa is obtained at 1.5 mPa and 15 s. Finally, the role of microstructural features on tensile strength of resultant joints is discussed.

关键词： friction welding AA-7005 aluminum alloy microstructure intermetallics tensile strength

Achalasia and thyroid disease

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World Journal of Gastroenterology 2007年第4期13卷 594-599页

作者： mohammad Hassan Emami mostafa Raisi Jaleh Amini hamed Daghaghzadeh Isfahan University of medical Sciences and Poursina Hakim Research Institution Isfahan Iran Poursina Hakim Research Institution Isfahan Iran

AIm: To investigate some possible etiologies of achalasia by screening patients with achalasia for some autoimmune diseases such as thyroid disease. mETHODS: We examined 30 known cases of achalasia (20 females, 10 males). Their age ranged 15-70 years. All of them were referred to our institute for treatment. Their sera were evaluated to detect some possible associations with rheumatoid disease, thyroid disease, inflammatory process, anemia, etc. RESULTS: Seven out of 30 patients (23%) had thyroid disease including four patients with hypothyroidism (13.3%), two patients with hyperthyroidism (6.6%), and one had only thyroid nodule but was in euthyroid state (3.3%). Two of these hypothyroid patients had no related clinical symptoms (subclinical) and two had clinical manifestations of hypothyroidism. There were no correlations between the intensity of thyroid diseases and the severity of achalasia symptoms. CONCLUSION: The etiology of achalasia is unknown although autoimmunity has been implicated and is supported by several studies. Thyroid disease presents concomitantly with achalasia in about one fourth of our patients who may have a common etiology.

关键词： Achalasia Thyroid disease Hypothyroidism Esophageal motility Etiology

Improvement of medium Composition and Utilization of mixotrophic Cultivation for Green and Blue Green microalgae towards Biodiesel Production

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Advances in microbiology 2014年第3期4卷 167-174页

作者： Seham m.hamed Gerd Klock microbiology Department SoilsWater and Environment InstituteAgricultural Research CenterGizaEgypt Biochemical Engineering Hochschule Bremen University of Applied SciencesBremenGermany

A possible source of biological material for the production of biodiesel is represented by microalgae, in particular by their lipid content. The aim of the present work was to optimize culture medium composition for improving growth and lipid content of green microalgae Chlorella sorokiniana, Scenedesmus acuminatus and blue green Cyanobacterium aponicum. Lipids were quantitatively determined by spectrofluorometric method using Nile red flurometric stain. Initially, the effect of two different medium types, Bold’s and optimized culture medium (OCm), four types of carbon source (glucose and sodium acetate, molasses, glycerol, control) and four nitrogen concentrations (100%, -75%, -50%, -25%) on the enhancement of biomass and lipid content and lipid productivity were studied;indeed, optimized culture medium significantly improved growth, CDW for three microalgae, beside increasing lipid content and lipid productivity for S. acuminatus and C. aponicum by 7.5 and 5 folds respectively at 25th day compared to Bold’s medium. moreover, 25% nitrogen deficient medium significantly increased lipid content and lipid productivity for both C. sorokiniana and C. aponicum at 2nd week of re-propagation to 10.6 and 2.6 folds over control (100% nitrogen). While S. acuminatus recorded the significant lipid content & productivity at 2nd week under recommended nitrogen dose in medium (100% N) by 4.4 folds over 25% deficient medium. meanwhile 0.3% glycerol medium enhanced CDW, lipid content of S. acuminatus to 1.68 gL-1. While C. sorokiniana and C. aponicum recorded significant CDW under 0.3% acetate medium 1.37 and 0.76 gL-1. C. aponicum exhibited no growth under glycerol medium. The highest lipid content and lipid productivity were obtained under glycerol medium for C. sorokiniana and S. acuminatus (64.3 and 52.8 mg·g·gǃ·dǃ).

关键词： Green microalgae Cyanobacteria mixotrophy Lipid Productivity Biomass Biodiesel Photobioreactor

Assessment of sediment yield using RS and GIS at two sub-basins of Dez Watershed,Iran

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International Soil and Water Conservation Research 2016年第3期4卷 199-206页

作者： hamed Noori Seyed mostafa Siadatmousavi Barat mojaradi School of Civil Engineering Iran University of Science&TechnologyNarmakTehran ***Iran

Soil erosion is a serious threat to soil and water resources in semi-arid *** Pacific Southwest Inter Agency Committee(mPSIAC)and Erosion Potential method(EPm),as two well-known models,have shown their performance in many case *** goal of present study is to assess the efficiency of these methods for estimating the sediments yield and erosion intensity within short-term and longterm timeframes over two sub-basins of Dez watershed,west of *** results showed that the study area can be categorized into slight,moderate,high and very high erosion *** half of the study area is highly susceptible to erosion due to the geological formations and land ***,the longterm(i.e.30 years)sediment yield of 387 and 615(kton)y^(-1) estimated by mPSIAC and EPm models demonstrated the superiority of *** to the measured value of 612(kton)y^(-1),the performance of EPm was *** splitting the dataset into six periods of five years,the sediment yield was predicted in short-term periods by both aforementioned *** segmentation provides the opportunity to evaluate the impact of extreme flooding events on the models *** results showed that both models failed in estimation of sediment load during flood ***,the correlation coefficients for estimating the sediment yield were found to be R=0.93 and R=0.85 for EPm and mPSIAC models respectively,for short-term simulations.

关键词： Soil erosion GIS Remote sensing modified Pacific South-West Inter Agency Committee method(mPSIAC) Erosion Potential method(EPm)

Imputing missing values using cumulative linear regression

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CAAI Transactions on Intelligence Technology 2019年第3期4卷 182-200页

作者： Samih m. mostafa Faculty of Science Mathematics DepartmentComputer ScienceSouth Valley UniversityQena 83523Egypt

The concept of missing data is important to apply statistical methods on the dataset. Statisticians and researchers may end up to an inaccurate illation about the data if the missing data are not handled properly. Of late, Python and R provide diverse packages for handling missing data. In this study, an imputation algorithm, cumulative linear regression, is proposed. The proposed algorithm depends on the linear regression technique. It differs from the existing methods, in that it cumulates the imputed variables;those variables will be incorporated in the linear regression equation to filling in the missing values in the next incomplete variable. The author performed a comparative study of the proposed method and those packages. The performance was measured in terms of imputation time, root-mean-square error, mean absolute error, and coefficient of determination (R^2). On analysing on five datasets with different missing values generated from different mechanisms, it was observed that the performances vary depending on the size, missing percentage, and the missingness mechanism. The results showed that the performance of the proposed method is slightly better.

关键词： Imputing missing values cumulative linear regression statistical methods

A multi-Factor Authentication-Based Framework for Identity management in Cloud Applications

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Computers, materials & Continua 2022年第5期71卷 3193-3209页

作者： Wael Said Elsayed mostafa m.m.Hassan Ayman m.hamed mostafa Faculty of Computers and Informatics Zagazig UniversityZagazig44519Egypt College of Computer and Information Sciences Jouf UniversitySakaka72314Saudi Arabia

User’s data is considered as a vital asset of several *** data to the cloud computing is not an easy decision for any organization due to the privacy and security *** providers must ensure that both data and applications that will be stored on the cloud should be protected in a secure *** data stored on the public cloud will be vulnerable to outside and inside *** paper provides interactive multi-layer authentication frameworks for securing user identities on the *** access control policies are applied for verifying users on the cloud.A security mechanism is applied to the cloud application that includes user registration,granting user privileges,and generating user authentication *** intrusion detection system is embedded to the security mechanism to detect malicious *** multi factor authentication,intrusion detection,and access control techniques can be used for ensuring the identity of the ***,encryption techniques are used for protecting the data from being *** results are carried out to verify the accuracy and efficiency of the proposed frameworks and *** results recorded high detection rate with low false positive alarms.

关键词： Cloud computing service providers multi-layer authentication frameworks and access control