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Surface hardness,thermal,optical,and photon attenuation coefficients assessment for dysprosium-doped tellurite glasses

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Journal of Rare Earths 2023年第7期41卷 1083-1090,I0004页

作者： h.sh.m.m.h.zakaly D.E.Abulyazied h.A.Saudi B.m.Alotaibi shams A.m.Issa Institute of Physics and Technology Ural Federal UniversityYekaterinburg620002Russia Faculty of Science Al-Azhar UniversityAssuit BranchAssuit71524Egypt Polymer Lab Department of PetrochemicalsEgyptian Petroleum Research InstituteNasr CityCairoEgypt Department of Physics Faculty of ScienceUniversity of TabukTabukSaudi Arabia Physics Department Faculty of ScienceAl-Azhar University(Girls Branch)Nasr CityCairoEgypt Department of Physics College of SciencePrincess Nourah Bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia

Using a melt-cooling process with the host glass,Dy_(2)O_(3)(1 wt%,2 wt%,3 wt%,and 4 wt%) doped tellurite glasses were produced.A(65-x)TeO_(2)-20B_(2)O_(3)-10Al_(2)O_(3)-SGeO_(2)-xDy_(2)O_(3) glass system was analyzed by Xray *** patterns have a hump at 2θ=27°-29° and no sharp peaks,indicating that all the glass samples are *** Vickers microhardness determines how resistant a glass is to persistent deformation produced by a harder *** scanning calorimetry(DSC) at 300-550℃ was used to evaluate the thermal properties of the Dy_x glass *** glass transition temperature T_g(small endothermic peak),start crystallization temperature T_x and crystallization temperature T_c can all be seen on the DSC thermogram(exothermic peaks).The UV-Vis transmittance and absorption spectra were *** optical data show that the values of E_d^(ir),E_g^(Ind) and E_U decrease as the amount of Dy_(2)O_(3)increases,indicating a narrowing of the tails due to localized states in the forbidden gap.A concentration quenching event occurs when Dy^(3+) concentrations are above a certain threshold(1%).The addition of Dy_(2)O_(3) increases glass density,while the addition of other Dy(Ⅲ) oxides increases sample *** radiation shielding values change as a consequence of density *** sample with the highest amount of Dy_(2)O_(3)(Dy_(4)) has stronger radiation shielding characteristics;hence,it is superior in terms of shielding outcomes at all energy *** Dy_x samples can be used in various forms of ionizing radiation shielding.

关键词： melt-cooling process DSC Dysprosium(Ⅲ)oxides Surface hardness Photon attenuation Rare earths

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Improving electrical,optical and radiation shielding properties of polyvinyl alcohol yttrium oxide composites

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Journal of Rare Earths 2023年第12期41卷 2002-2009,I0007页

作者： shams A.m.Issa D.E.Abulyazied Albandari W.Alrowaily h.A.Saudi E.S.Ali A.m.A.henaish h.sh.m.m.h.zakaly Department of Physics Faculty of ScienceUniversity of TabukTabukSaudi Arabia Faculty of Science Al-Azhar UniversityAssiut BranchAssiut71524Egypt Polymer Lab Department of PetrochemicalEgyptian Petroleum Research InstituteNasr CityCairoEgypt Department of Physics College of SciencePrincess Nourah Bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Physics Department Faculty of ScienceAl-Azhar University(Girls Branch)Nasr CityCairoEgypt Institute of Physics and Technology Ural Federal UniversityYekaterinburg620002Russia Physics Department Faculty of ScienceTanta UniversityTanta31527Egypt Istinye University Faculty of Engineering and Natural SciencesComputer Engineering DepartmentIstanbul34396Turkey

This research aims to study the impact of yttrium oxide on the radiation protection features of polyvinyl alcohol(PVA) for gamma shielding *** yttrium oxide(Y_(2)O_(3)) was instilled through the PVA matrix by different contents(x=0.1 wt%,0,3 wt%,0,7 wt%,0,9 wt%),The morphology of the prepared PVA/Y_(2)O_(3)composites was characterized using scanning electron microscopy(SEm).The samples were investigated using absorption edge,transmittance spectra and dielectric *** transmittance and the bandgap energy decrease as the Y2O3content increases while there is an increase in ε’ and ε" as well as the ac conductivity with the content increment of Y_(2)O_(3)till 0.7 wt%.The te mperature dependence of the dc conductivity was measured for all samples in the range of 260-460 K,and it increases with the temperature *** correlate the electrical characteristics of the PVA/Y_(2)O_(3)composites with their structure and evaluate electrical properties with the help of equivalent circuit matching with the experimentally electrical response in the impedance spectrum,the radiation protection properties were also investigated to get the radiation shielding performance of these PVA/Y_(2)O_(3)composite films with varying Y_(2)O(3)*** linear attenuation coefficient(μ),half value layer(T_(0.5)),and mass attenuation coefficient(μm) were *** to all obtained data,PVA/Y_(2)O_(3)composite films with various percentages(0.1 wt%,0.3 wt%,0.7 wt%,0.9 wt%) can be used as a radiation shielding material.

关键词： Yttriumoxide/PVA Electrical properties Optical properties Gamma shielding Rare earths

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Inverse heat Transfer Problem of Thermal Contact Conductance Estimation in Periodically Contacting Surfaces

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Journal of Thermal Science 2009年第2期18卷 150-159页

作者： m.h.shojaeefard K.Goudarzi m.sh.mazidi Dept. of mechanical Engineering Iran University of Science and Technology

The problems involving periodic contacting surfaces have different practical applications. An inverse heat conductionproblem for estimating the periodic Thermal Contact Conductance (TCC) between one-dimensional, constantproperty contacting solids has been investigated with conjugate gradient method (CGm) of function *** method converges very rapidly and is not so sensitive to the measurement errors. The advantage of thepresent method is that no a priori information is needed on the variation of the unknown quantities, since the solutionautomatically determines the functional form over the specified domain. A simple, straight forward techniqueis utilized to solve the direct, sensitivity and adjoint problems, in order to overcome the difficulties associatedwith numerical methods. Two general classes of results, the results obtained by applying inexact simulatedmeasured data and the results obtained by using data taken from an actual experiment are presented. In addition,extrapolation method is applied to obtain actual results. Generally, the present method effectively improves theexact TCC when exact and inexact simulated measurements input to the analysis. Furthermore, the results obtainedwith CGm and the extrapolation results are in agreement and the little deviations can be negligible.

关键词： thermal contact inverse problem conjugates gradient method

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Sorption of certain lanthanides by kieselguhr loaded with Cyanex 572 from sulfate medium

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Journal of Rare Earths 2020年第3期38卷 299-305页

作者： sh.sh.Emam m.S.Gasser N.E.El-hefny W.h.mahmoud h.F.Aly hot Laboratories Centre Atomic Energy AuthorityCairo 13759Egypt Department of Chemistry Faculty of ScienceAin Shams UniversityCairoEgypt

Kieselguhr for chromatography was loaded with Cyanex 572 extractant and characterized using X-ray diffraction(XRF),scanning electron microscopy(SEm),Fourier transform infra-red(FT-IR),and thermal *** of some heavy lanthanides together with yttrium by the prepared kieselguhr/Cy-572 sorbent was investigated by batch experiment in terms of initial metal ions concentrations,volume to solid mass ratio(V/m),sulfuric acid concentration as well as *** sorption equilibrium of Cy-572 loaded kieselguhr was satisfactorily explained by the pseudo second-order kinetic model and Langmuir isotherm ***,the values of thermodynamic parameters △G°,△h°,and △S°at25℃of the studied metal ions show that the process is spontaneous and endothermic in nature.2.0 mol/L hNO3 is promising to desorb these metal ions.

关键词： Sorption Cyanex 572 Lanthanides Kieselguhr Sulfate medium Rare earths

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Comparative studies on Y(Ⅲ)and Dy(Ⅲ)extraction from hydrochloric and nitric acids by Cyanex 572 as a novel extractant

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Journal of Rare Earths 2018年第12期36卷 1342-1350页

作者： N.E.El-hefny m.S.Gasser sh.sh.Emam W.h.mahmoud h.F.Aly hot Laboratories Centre Atomic Energy Authority Faculty of Science Ain Shams University

Extraction of Y(III) and Dy(III) from hydrochloric and nitric acids by Cy-572 in kerosene was studied. The factors affecting the extraction were separately investigated. The stoichiometry of the extracted species was deduced on the basis of slope analysis method. Evaluation of extraction equilibrium and stripping investigation was studied as well as saponification effect of Cy-572. The composition of the extracted metal species in the organic phase was found to be [mA·(hA)] for Y(III) or Dy(III) in both media.1.0 mol/L hCI is the best stripping agent for each metal ion from the studied acidic media in one *** Cy-572 does not exhibit any selectivity towards the extraction of Y(III) or Dy(III) from both hCI and hNOsolutions. Based on the obtained results, the data were compared and the separation feasibility between lanthanides and Y(III) in the two media was discussed.

关键词： Extraction Cyanex-572 Yttrium Lanthanides Separation factor Saponification

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Experimental and numerical study on plasma nitriding of AISI P20 mold steel

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International Journal of minerals,metallurgy and materials 2016年第9期23卷 1065-1075页

作者： N.Nayebpashaee h.Vafaeenezhad sh.Kheirandish m.Soltanieh materials Processing Simulation Laboratory(mPS-LAB) School of Materials and Metallurgical EngineeringIran University of Science and Technology(IUST) School of materials and metallurgical Engineering Iran University of Science and Technology(IUST)

In this study, plasma nitriding was used to fabricate a hard protective layer on AISI P20 steel, at three process temperatures（450℃, 500℃, and 550℃） and over a range of time periods（2.5, 5, 7.5, and 10 h）, and at a fixed gas N2：h2 ratio of 75vol%：25vol%. The morphology of samples was studied using optical microscopy and scanning electron microscopy, and the formed phase of each sample was determined by X-ray diffraction. The elemental depth profile was measured by energy dispersive X-ray spectroscopy, wavelength dispersive spectroscopy, and glow dispersive spectroscopy. The hardness profile of the samples was identified, and the microhardness profile from the surface to the sample center was recorded. The results show that ε-nitride is the dominant species after carrying out plasma nitriding in all strategies and that the plasma nitriding process improves the hardness up to more than three times. It is found that as the time and temperature of the process increase, the hardness and hardness depth of the diffusion zone considerably increase. Furthermore, artificial neural networks were used to predict the effects of operational parameters on the mechanical properties of plastic mold steel. The plasma temperature, running time of imposition, and target distance to the sample surface were all used as network inputs; Vickers hardness measurements were given as the output of the model. The model accurately reproduced the experimental outcomes under different operational conditions; therefore, it can be used in the effective simulation of the plasma nitriding process in AISI P20 steel.

关键词： tool steel plasma nitriding sputtering neural networks

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Study of Sintering Behaviour and Electrical Conductivity of Cr-Zn-Fe-O System

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Journal of materials Science & Technology 1999年第1期15卷 79-82页

作者： hanna, A.A. Khalil, m.sh. Saleh, h.I. Ali, A.F. Inorganic Chemistry Department National Research Centre Dokki Cairo Egypt

A series of chemical composition based on Cr, Fe and O with Zn as a partially substituting ion has been prepared in the general formula Zn//xCr//1// minus //xFe//2O by coprecipitation method using Nh//4Oh as the precipitating agent at ph equals 10.3. The prepared samples were identified by both thermal analysis (DTA and TGA) and X-ray diffraction. It was found that no single phase is obtained for any of the studied compositions but a mixture of different phases is observed, depending on the molar percentage of zinc ion substitution as well as on the sintering temperature. The temperature dependence of the electrical conductivity, sigma , of the prepared samples is plotted between 25 and 680 degree C. It was observed that the electrical conductivity increases with temperature for both samples with x equals 0.00 and 0.80 Zn ion content while it is nearly temperature independent for samples with intermediate Zn concentration x equals 0.2 and 0.5 mol fraction. The activation energy, E//a, calculated from the linear relation, lg sigma -1000/T for the final mixtures (sintered at 1300 degree C) was calculated. (Edited author abstract) 16 Refs.

关键词： Chromium compounds

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Sliding Wear Behavior of a Grey Cast Iron Surface Remelted by TIG

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Journal of materials Science & Technology 2009年第5期25卷 622-628页

作者： h.mohamadzadeh h.Saghafian sh.Kheirandish Department of metallurgy and materials Engineering Iran University of Science and TechnologyTehranIran

The sliding wear behavior of a grey cast iron surface remelted by tungsten inert gas （TIG） was studied and compared with the unremelted one in the current work. To evaluate the wear behavior a Pin-on-Disk wear test machine was used. Pins which were prepared from the samples with the remelted layers of different thicknesses of 1.2, 1.8, 2.5 and 3 turn were worn on an AISID3 steel counterface having a hardness of 63hRC under the applied loads of 54, 76 and gg N at a constant sliding velocity of 0.45 m/s. Scanning electron microscopy （SEm） equipped with energy dispersive X-ray analysis （EDS） and X-ray diffraction （XRD） techniques were used to characterize worn surface and subsurface and also wear debris obtained from the wear tests under different test conditions. Results showed that surface remelted grey cast iron have better wear properties for all applied normal loads in comparison with unremelted ones. microscopic studies on the worn surfaces and subsurfaces of samples revealed that dominant wear mechanism for surface remelted samples was mild oxidative, while it was severe for unremelted samples. Increasing remelted layer thickness and then forming grosser microstructure lead to a decline of wear properties, whereas lower thickness of remelted layer with finer microstructure due to having higher cooling rate through remelting process can withstand better against wear.

关键词： Grey cast Iron Surface remelted Tungsten inert gas (TIG) Wear

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Laguerre reproducing kernel method in hilbert spaces for unsteady stagnation point ow over a stretching/shrinking sheet

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Applied mathematics(A Journal of Chinese Universities) 2021年第3期36卷 354-369页

作者： m.R.Foroutan A.S.Gholizadeh sh.Najafzadeh R.h.haghi Department of mathematics Payame Noor UniversityP O Box 19395-3697TehranIran

This paper investigates the nonlinear boundary value problem resulting from the exact reduction of the Navier-Stokes equations for unsteady magnetohydrodynamic boundary layer flow over the stretching/shrinking permeable sheet submerged in a moving *** solve this equation,a numerical method is proposed based on a Laguerre functions with reproducing kernel hilbert space *** the operational matrices of derivative,we reduced the problem to a set of algebraic *** also compare this work with some other numerical results and present a solution that proves to be highly accurate.

关键词： nonlinear boundary value problem Laguerre reproducing kernel method operational matrix of derivative existence and nonexistence of solutions approximate solution

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An authentication and plausibility model for big data analytic under LOS and NLOS conditions in 5G-VANET

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Science China(Information Sciences) 2020年第12期63卷 67-83页

作者： S.A.SOLEYmANI m.h.ANISI A.hanan ABDULLAh m.Asri NGADI sh.GOUDARZI m.Khurram KhAN m.Nazri KAmA School of Computing Faculty of Engineering Universiti Teknologi Malaysia (UTM) School of Computer Science and Electronic Engineering University of Essex Centre of Artificial Intelligence National University of Malaysia (UKM) Center of Excellence in Information Assurance (CoEIA) King Saud University Advanced Informatics School Menara Razak Universiti Teknologi Malaysia (UTM)

The exchange of correct and reliable data among legitimate nodes is one of the most important challenges in vehicular ad hoc networks(VANETs). malicious nodes and obstacles, by generating inaccurate information, have a negative impact on the security of 5G-VANET. The big data generated in the vehicular network is also an issue in the security of VANET. To this end, a security model based on authentication and plausibility is proposed to improve the safety of network named ‘AFPm’. In the first layer, an authentication mechanism using edge nodes along with 5G is proposed to deal with the illegitimate nodes who enter the network and broadcast wrong information. In the authentication mechanism, because of the growth of the connected vehicles to the edge nodes that lead to generating big data and hence the inappropriateness of the traditional data structures, cuckoo filter, as a space-efficient probabilistic data structure, is used. In the second layer, a plausibility model by performing fuzzy logic is presented to cope with inaccurate information. The plausibility model is based on detection of inconsistent data involved in the event message. The plausibility model not only tackles with inaccurate, incomplete, and inaccuracy data but also deals with misbehaviour nodes under both line-of-sight(LOS) and non-line-of-sight(NLOS) conditions. All obtained results are validated through well-known evaluation measures such as F-measure and communication overhead. The results presented in this paper demonstrate that the proposed security model possesses a better performance in comparison with the existing studies.

关键词： authentication plausibility fuzzy logic cuckoo filter 5G-VANET big data

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