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Energy Storage and Saving 2022年第4期1卷 259-271页

作者： Atef Chibani Slimane Merouani Aissa Dehane cherif Bougriou Laboratory of Environmental Process Engineering Department of Chemical EngineeringUniversity Salah Boubanider Constantine 3ConstantineP.O.Box 72Algeria Department of Mechanical Engineering University of Mostefa Ben BoulaidBatna 2Batna05000Algeria Department of Process Engineering Faculty of Sciences and Applied SciencesLarbi Ben M’hidi University04000Oum El BouaghiAlgeria

An advanced ANSYS FLUENT-based model was developed for hydrogen recovery from a multi-tubular fixed-bed metal hydride(MH)reactor of large-scale *** model was firstly validated by comparing its results to specific experimental *** and heat transfer processes inside the fixed bed were investigated for various pressures and thermochemical characteristics of the MH(thermal conductivity,porosity and reaction parameters).The findings were reported as average,local and spatial changes in the metal’s bed temperature and hydrogen *** the initial stage of the endothermic desorption(telease continued until the MH was completely *** dehydrogenation rate of the MH was enhanced when the discharge pressure was ***,some other characteristics of the MH,i.e.,porosity,thermal conductivity,desorption rate constant and activation energy,significantly impacted the resulting mass and heat fluxes inside the bed material.

关键词： Hydrogen storage Metal hydride(MH) Desorption Heat and mass transfer Mathematical model

Sol-gel synthesis,properties and protein loading/delivery capacity of hollow bioactive glass nanospheres with large hollow cavity and mesoporous shell

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Frontiers of Materials Science 2022年第3期16卷 145-157页

作者： Ahmed el-FIQI Glass Research Department National Research CentreCairo 12622Egypt

Hollow nanospheres exhibit unique properties and find a wide interest in several potential applications such as drug ***,novel hollow bioactive glass nanospheres(HBGn)with large hollow cavity and large mesopores in their outer shells were synthesized by a simple and facile one-pot ultrasound assisted sol-gel method using PEG as the core ***,the produced HBGn exhibited large hollow cavity with ~43 nm in diameter and mesoporous shell of ~37 nm in thickness and 7 nm pore size along with nanosphere size around 117 *** confirmed the presence of Si and Ca elements at the surface of the HBGn outer ***,HBGn showed high protein loading capacity(~570 mg of Cyto c per 1 g of HBGn)in addition to controlled protein release over 5 *** also demonstrated a good in vitro capability of releasing calcium(Ca^(2+):170 ppm)and silicate(SiO_(4)^(4-):78 ppm)ions in an aqueous medium over 2 weeks under physiological-like *** in vitro growth of bone-like hydroxyapatite nanocrystals was exhibited by HBGn during the soaking in SBF.A possible underlying mechanism involving the formation of spherical aggregates(coils)of PEG was proposed for the formation process of HBGn.

关键词： bioactive glass hollow nanosphere hollow cavity mesoporous shell soft-template ultrasound assisted sol-gel synthesis therapeutic protein delivery

Three-dimensional printing of biomaterials for bonetissue engineering: a review

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Frontiers of Materials Science 2023年第2期17卷 1-43页

作者： Ahmed el-Fiqi Glass Research Department Advanced Materials Technology and Mineral Resources Research InstituteNational Research CentreCairo 12622Egypt

Processing biomaterials into porous scaffolds for bone tissueengineering is a critical and a key step in defining and controlling their physicochemical,mechanical,and biological *** such as polymers are commonlyprocessed into porous scaffolds using conventional processing techniques,e.g.,***,these traditional techniques have shown unavoidable limitations andseveral *** instance,tissue-engineered porous scaffolds with a complexthree-dimensional(3D)geometric architecture mimicking the complexity of theextracellular matrix of native tissues and with the ability to fit into irregular tissue defectscannot be produced using the conventional processing techniques.3D printing hasrecently emerged as an advanced processing technology that enables the processing ofbiomaterials into 3D porous scaffolds with highly complex architectures and tunableshapes to precisely fit into irregular and complex tissue defects.3D printing providescomputer-based layer-by-layer additive manufacturing processes of highly precise andcomplex 3D structures with well-defined porosity and controlled mechanical propertiesin a highly reproducible ***,3D printing technology provides anaccurate patient-specific tissue defect model and enables the fabrication of a patientspecifictissue-engineered porous scaffold with pre-customized properties.

关键词： 3D printing biomaterial ink printability 3D printing technique 3D printed scaffold bone tissue engineering

Intercalation and Stability of Layered Semiconductive Material in Corrosive Environment

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Journal of Materials Science & Technology 2006年第2期22卷 252-256页

作者： A.A.el-Meligi electrochem.and Corrosion Lab. Physical Chemistry Dept. National Research CentreDokkiCairoEgypt

The intercalation of 4-methyl pyridine （4-picoline） into layered semiconductive material （MnPS3） and the stability of the resulting materials in corrosive environments （water, HCI and open atmosphere） were investigated. Powder X-ray diffraction （XRD） indicated that the presence of water and hydrochloric acid greatly influenced the existing form of intercalation and its orientation in the interlayer of the host. Atmospheric environment （open air） affected the guest orientation in the interlayer of the host material. Phase transformation occurred and the material was stable. The intercalated compounds could be indexed in the trigonal unit cell. The XRD patterns exhibited sharp hkl reflections of the intercalated compounds, which formed in water and HCI, confirming that the materials were well crystalline and stable in corrosive environments.

关键词： MnPS3 Intercalation Stability XRD Corrosive environments

Effect of Heating Rates on the Formable Oxide Scale on a C-Steel Surface

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Journal of Materials Science & Technology 2004年第5期20卷 591-594页

作者： A.A.el-Meligi electrochemistry and Corrosion Lab. Dept.of Physical ChemistryNational Research CentreDokkiCairoEgypt

Oxide scale formation on a C-steel surface has been investigated using linear heating rates ranging from 0.1℃/min to 10℃/min at high temperatures. The studies on the oxide scale formation at high temperature (650℃) at slower heating rate (0.1℃/min) shows that the kinetic regime is linear. X-ray diffraction measurements revealed that the scale constituents are significantly influenced by the heating rate. The adherence of the scale was improved by using slower heating rate (0.1℃/min-≤650℃), while above such degree the scale was susceptible to cracking and flaking out of the alloy surface. In fact, the development of oxide growth stresses can cause considerable scale cracking. As well, variation of the crystallite sizes under the aforementioned conditions might affect the scale stacking to the alloy surface. The secondary electron detector images of the oxide scale shows that the scale was imperfectly smooth and there were a number of voids and defects in the scale skin, especially at fast heating rate. This observation could be attributed to defects of the as-received alloy. In general, slower heating rate reduced the defects of the scale and improved its adherence.

关键词： C-steel Oxide scale Heating rate Weight gain XRD

Corrosion Behaviours of Copper Alloy in Solutions Containing Na_2SO_4 and NaCl with Different Concentrations

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Journal of Materials Science & Technology 2002年第6期18卷 549-551页

作者： A.A.el-Meligi Chem. Dept. Durham Univ. Durham DH1 3LE South Road United Kingdom

Potentiodynamic polarisation, potential-time measurements, X-ray diffraction (XRD) and infrared spectroscopy (IR) have been used to investigate the effect of different concentrations of Na2SO4 in the absence and presence of NaCI, on the corrosion of Cu-alloy. The electrochemical measurements showed that the increase of Na2SO4 concentration led to increase the corrosion current density of Cu alloy and vice versa. The presence of NaCI shifted the potential to more cathodic potential, which had a great influence on the protectiveness of the Cu oxide layer formed on the surface in presence of Na2SO4. The spectrometric measurements indicated the constituents of the film formed on the alloy surface were mainly Cu2O, in addition to the oxides, NiO and Fe2O3, which were traced by XRD analysis.

关键词： Cu-alloy Polarisation X-ray diffraction Na2SO4 NaCl Oxide film

New Conditions for Intercalation of Organic Compounds into Semiconductor Nanomaterial

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Journal of Materials Science & Technology 2009年第4期25卷 470-474页

作者： A.A. el-Meligi National Research Centre Physical Chemistry Department

The intercalation of organic guests, 2-methyl pyridine （2-picoline） and 3-methyl pyridine （3-picoline） into semiconductor layered nanomaterial （MnPS3） was investigated. New conditions were applied. New phases appeared and lattice expansions were 0.36 nm for 2-picoline intercalation and 0.728 nm for 3-picoline inter- calation. The XRD （X- ray diffraction） patterns exhibit sharp hkl reflections confirming that the material is highly crystalline. The interlayer gap （0.64 nm） of the host plays a role for the arrangement of the guest in the interlayer region. The crystal structure of the MnPS3 was indexed in the monoclinic system before inter- calation. After intercalation, the crystal system was indexed in the trigonal unit cell. The lattice parameters were obtained and c-axis value was related to the （001） reflections.

关键词： Layered nanomaterials Organic guest Intercalation X-ray diffraction

First-principles prediction of the magnetism of 4f rare-earth-metal-doped wurtzite zinc oxide

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Journal of Rare Earths 2014年第8期32卷 715-721页

作者： A.G.el Hachimi H.Zaari A.Benyoussef M.el Yadari A.el Kenz Laboratoire de Magnétisme et Physique des Hautes Energies LMPHE (URAC 12) Département de Physique B.P.1014 Faculté des SciencesUniversité Mohammed V-Agdal Institut of Nanomaterials and Nanotechnology Hassan II Academy of Science and Technology Department of Science Moulay Ismail University Faculté Polydisciplinaire

electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth （RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb） atoms were studied using spin-polarized density functional theory based on the full-potential linear augmented plane wave （FP-LAPW） method as implemented in the Wien2k code. In this approach the generalized gradient approximation （GGA） was used for the exchange-correlation （XC） potential. Our results showed that the substitution of RE ions in ZnO induced spins polarized localized states in the band gap. Moreover, the studied DMSs compounds retained half metallicity at dopant concentration x=0.625%for most of the studied elements, with 100%spin polarization at the Fermi level （EF）. The total magnetic moments of these compounds existed due to RE 4f states present at EF, while small induced magnetic moments existed on other non-magnetic atoms as well. Finally, the energy difference between far and near configurations was investigated. It was found that the room temperature ferromagnetism was possible for RE-doped ZnO at near configuration. Since the RE-RE separation was long enough （far configuration） for magnetic coupling, the system became paramagnetic or antiferromagnetic ground state.

关键词： ZnO rare earths ferromagnetism DMS electronic structure magnetic properties half-metallic RE-doped ZnO FP-LAPW method density functional theory

Improvement of groundwater resources potential by artificial recharge technique: A case study of Charf el Akab aquifer in the Tangier region, Morocco

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Journal of Groundwater Science and Engineering 2019年第3期7卷 224-236页

作者： SADIKI Moulay Lhassan el MANSOURI Bouabid BENSEDDIK Badr CHAO Jamal KILI Malika el MEZOUARY Lhoussaine Laboratory of Geosciences of Natural Resources Hydroinformatic sectionFaculty of SciencesIbn Tofail UniversityMaamora CampusBP.1331400 KénitraMorocco Mathematical Analysis Laboratories Non-commutative Geometry and ApplicationsFaculty of ScienceIbn Tofail UniversityMaamora CampusBP.1331400 KénitraMorocco.

In arid and semi-arid zones,water is the most vulnerable resource to climate *** fact,various techniques such as artificial recharge are adopted to restore aquifers and to ensure aquifer sustainability in relation to the accelerated pace of *** is a Mediterranean country highly vulnerable to climate change,many of its main aquifers are subjected to excessive *** technique is practiced to increase potentiality of these *** the Northwestern area of Morocco,the significant development experienced by Tangier City in the industrial,tourism,and commercial sectors will lead to increased water requirements-up to 5 067 L/s(159.8 mm^3)by ***,the Charf el Akab aquifer system,subject to artificial recharge,is the only groundwater resource of Tangier region;hence,a rational management context is needed to ensure aquifer sustainability,and optimized exploitation under the background of differing constraints,such as increased water requirements,and climate change *** work aims to respond,for the first time,to the Charf el Akab aquifer overexploitation problem,and to evaluate the future scenarios of its exploitation in the event of failure of one of the superficial *** work also presents a synthesized hydrodynamic modeling based on the results of the numerical simulations carried out using Feflow software for 2004(date of cessation of injections)and 2011(date of resumption of these facilities),making it possible to evaluate the impact of the artificial recharge on the piezometric level of the aquifer on a spatiotemporal ***,the exploitation scenarios have shown that the aquifer of Charf el Akab will not adequatly provide for the region's water requirements on the future horizon,entailing an optimal management of water resources in the region and an intentionally increased recharge rate.

关键词： Artificial recharge Climate change Numerical modeling Chaf el Akab Feflow Exploitation scenarios

Formation of Alfvénic supernonlinear waves in a plasma containing double spectral distributed electrons

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Communications in Theoretical Physics 2024年第12期76卷 140-149页

作者： A A el-Tantawy W F el-Taibany S K el-Labany A M Abdelghany Department of Physics Faculty of Science Damietta University Center of Space Research and Its Application Damietta University

The characteristics of nonlinear and supernonlinear Alfvén waves propagating in a multicomponent plasma composed of a double spectral electron distribution and positive and negative ions were investigated. The Sagdeev technique was employed, and an energy equation was derived. Our findings show that the proposed system reveals the existence of a double-layer solution, periodic, supersoliton, and superperiodic waves. The phase portrait and potential analysis related to these waves were investigated to study the main features of existing waves. It was also found that decreasing the electron temperature helps the superperiodic structure to be excited in our plasma model. Our results help interpret the nonlinear and supernonlinear features of the recorded Alfvén waves propagating in the ionosphere D-region.

关键词： Alfvén waves double spectral distribution nonlinear waves Sagdeev method supernonlinear waves