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Structural Studies on Ag2O-P2O5Glasses

New Journal of Glass and Ceramics 2017年第3期7卷 77-89页

作者： gomaa el-damrawi Abdelmajued Hassan Hamdy Doweidar Ahamed Shaboub Glass Research Group Physics Department Faculty of Science Mansoura University Mansoura Egypt

Silver phosphate glasses of general formula xAg2O·(100 - x)P2O5 have been investigated over compositional range from x = 40 to 62.5 mol%. The local structure around phosphorus atom has been studied via 31P nuclear magnetic resonance. The distribution of [PO4]Qn species as a function of composition has been shown to slightly deviate from the simple binary alkali phosphate model. An anomalous behavior has been recorded and interpreted in terms of mixed ring-chain effect in metaphosphate composition. The splitting of NMR spectra into sub resonances is assigned to different binding sites characterizing Q1 ring and Q1 chain structure. Higher Ag2O concentration (≥50 mol%) leads to formation of phosphate groups with specific resonance peaks which are mainly related to pyro and orthophosphate species. The rate of change of the chemical shift of the 31P NMR depends on the bond type, which in turn reflects the extent of double bonding between phosphorus and oxygen atoms. Increasing concentration of Q0 with increasing Ag2O content leads to decreasing quantities of bridging and double bonds. As a consequence, specific symmetric resonance peak of higher intensity and chemical shift (Q0) is a feature of silver rich glasses (orthophosphate). The latter species is therefore proposed to compose of separated membered rings,?which cause deshielding of phosphate units.?XRD and EDP studies have shown that, amorphous phosphate network is the dominant structure of glasses containing ≤ 55 mol% Ag2O. Some ordered and well crystallized phases are formed at higher Ag2O concentration. Increasing non-bridging oxygen atoms is shown to have the main effect on crystallization behavior. Orthophosphate composition is the most crystalline one among the other compositions (ultra, meta- and pyrophosphate). Presence of orthophosphate species which typically contains highest concentration from isolated Q0 units is the main reason for building up crystalline Ag3PO4phosphate phase.

关键词： Nuclear Magnetic Resonance Chemical Shift Phosphate Species Orthophosphates

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Structural Characterization of Novel Cerium Phosphate Glass Ionomer Cements (GICs) Doped with GaCl (Phthalocyanine)

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New Journal of Glass and Ceramics 2018年第2期8卷 23-38页

作者： gomaa el-damrawi Amal Behairy Amr M. Abdelghany Glass Research Group Physics Department Faculty of Science Mansoura University Mansoura Egypt The High Institute of Engineering and Technology New Damietta Egypt Spectroscopy Department Physics Division National Research Center Giza Egypt

Cerium Pyrophosphate glass is prepared and investigated by different structural techniques. Resin modified glass ionomer cements (RGICs) of pyro cerium phosphate (40CeO2-60P2Os) composition doped with different concentrations from GaCl Phthalocyanine (C32H16ClGaN8) have been also prepared and studied for the first time. Different techniques have been applied to shed?light on the structural changes induced upon addition of GaCl-Phthalocyanine. The corresponding changes in material structure are widely approved by results of 31P magic angle spinning nuclear magnetic resonance (MAS-NMR), X-Ray diffraction and FTIR spectroscopy. The network structure of both base glass and GIC free from C32H16ClGaN8 is confirmed to be amorphous. Doping even with little concentration from GaCl-Phthalocyanine leads to changing the network structure from amorphous to a highly crystalline one. Formulation of GaCl-Phthalocyanine with water soluble acid leads to monocrystalline structure due to monoclinic lattice structure of Phthalocyanine. Carbonated hydroxyl cerium and gallium phosphate structural phases are evidenced to be formed upon GaCl-Phthalocyanine addition. Presence of such bioactive phases can support that the prepared GICs of considerable C32H16ClGaN8 concentration (1 and 1.5 mol%) can be applied as biocompatible materials used in biodental applications. The morphologies of some selected samples were characterized by SEM. The micrographs have revealed that formulating of cerium phosphate powder of the amorphous glass with polymeric acid successfully led to the formation of CePO4-H2O nanofibrous bundles. But formulation with GIC containing GaCl-Phthalocyanine can simply form co-aligned and elongated nanofibers (15 - 40 nm thick and up to ca. 1.2 m long). The formed nanofibers are mainly consisted of hydrated and carbonated CePO4 and GaPO4 nanocrystals. The hardness of the cemented material increases with increasing GaCl-Phthalocyanine concentrations.

关键词： Glass Ceramics-GIC-Crtstalline Structure Spectroscopy

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Advantage of NMR and FTIR Spectroscopy to Determine Structure Role of CeO2in Complicated Borosilicate Glasses: New Approach

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New Journal of Glass and Ceramics 2017年第2期7卷 22-33页

作者： gomaa el-damrawi Abdelmeguid K. Hassan Salma Ehmead Amal el Shahawy Physics Department Faculty of Science Mansoura University Mansoura Egypt

Microstructure of complicated glasses in the system 30Na2O-2Al2O3-25 SiO2-xCeO2 (43-x) B2O3, x changes from 0.5 to 20 mol% have been extensively studied. Structural determination of glasses containing high cerium oxide content (≥8 mol% CeO2) was carried out by 11B NMR and FTIR spectroscopy. On the other hand, 29Si MAS NMR experiment is hardly to be applied to glasses of CeO2 > 8 mol%. This is due to the paramagnetic action which is raised by cerium cations causing dilution or delaying in the resonance phenomenon. It is evidenced from NMR data that sodium oxide is high enough to modify the glass forming units which constitute the skeleton of the glass. Ceria is as well as silica and B2O3 all are acting as glass forming species. Decreasing of both fraction of boron tetrahedral units (N4) and chemical shift of silicon nuclei (δ) confirm the role of CeO2 as a glass former. On the other hand, fast decrease in N4 and chemical shift of Si nuclei with further increasing CeO2 contents (≥8 mol%) gives a clear evidence that the ability of cerium oxide to participate as a network former increases with increasing its content. New approach is applied to determine the fraction of CeO4 as a glass forming units. In this approach, we use the common advantage of 11B NMR and FTIR spectroscopy to obtain Ce4 fraction. The latter species cannot be determined from NMR spectroscopy, since very high relaxation time and magnetization of ceria cause intensive spectral broadening which prevent resonance spectra to be appeared.

关键词： NMR Spectroscpy Cerium Oxide New Approach Glasses

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Enhanced heavy and extra heavy oil recovery:Current status and new trends

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Petroleum 2024年第3期10卷 399-410页

作者： Sayed gomaa Khalaf G.Salem A.N.el-hoshoudy Mining and Petroleum Engineering Department Faculty of EngineeringAl-Azhar UniversityEgypt Department of Reservoir Engineering South Valley Egyptian Petroleum Holding Company(GANOPE)CairoEgypt PVT Lab-Production Department Egyptian Petroleum Research Institute(EPRI)Cairo 11727Egypt PVT-Service Center Egyptian Petroleum Research Institute(EPRI)Cairo 11727Egypt

Due to the increased demand for energy resources these days,especially due to the Russian-Ukrainian war,the focus of the major countries is turning strongly towards improving oil production,especially heavy and extra heavy oil,which represents 40%of the world oil ***-based and thermal(EOR)procedures are promising techniques for recovering heavy oil reservoirs,but they suffer from a sequence of problems and complications that arise after long-term *** complications comprise steam breakthrough,steam overlap,and steam/rock *** research presents the currently applied techniques to maximize the productivity of heavy oil,such as steam injection,cyclic steam stimulation,in-situ combustion,and steam-assisted gravity *** technologies face numerous obstacles,as they are energy and water-intensive processes that are not environmentally *** research also presents future trends in energy-saving and environmentally friendly techniques that enhance heavy oil recovery through vapor extraction(VAPEX)steam-solvent hybrid techniques,electromagnetic energy,sonication,and *** findings of this review reported that all the presented techniques focus on how to reduce the oil viscosity and in-situ upgrade the crude oil *** turn,these enhance both the productivity rate and oil recovery and minimize the production *** article can be considered a comprehensive review of thermal recovery methods in heavy and extra-heavy oil,in addition to screening criteria used for each method.

关键词： Enhanced oil recovery Heavy crude oil Steam flood Hybrid techniques Nanotechnology

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Strain engineering in electrocatalysis:Strategies,characterization,and insights

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Nano Research 2024年第5期17卷 3603-3621页

作者： Qibo Deng Peng Xu Hassanien gomaa Mohamed A.Shenashen Sherif A.el-Safty Cuihua An Li-Hua Shao Ning Hu School of Mechanical Engineering Hebei University of TechnologyTianjin 300401China Department of Chemistry Faculty of ScienceAl-Azhar University71524AssiutEgypt Department of Petrochemical Egyptian Petroleum Research Institute(EPRI)Nasr City11727CairoEgypt Center for Functional Materials National Institute for Materials Science(NIMS)1-2-1 SengenTsukubaIbaraki-ken305-0047Japan State Key Laboratory of Reliability and Intelligence electrical Equipment Key Laboratory of Advanced Intelligent Protective Equipment TechnologyMinistry of Educationand School of Mechanical EngineeringHebei University of TechnologyTianjin 300401China National Key Laboratory of Strength and Structural Integrity Institute of Solid MechanicsSchool of Aeronautic Science and EngineeringBeihang UniversityBeijing100191China Advanced Equipment Research Institute Co. Ltd.of HEBUTTianjin 300401China

Strain engineering,as a cutting-edge method for modulating the electronic structure of catalysts,plays a crucial role in regulating the interaction between the catalytic surface and the adsorbed *** electrocatalytic performance is influenced by the electronic structure,which can be achieved by introducing the external forces or stresses to adjust interatomic spacing between surface *** challenges in strain engineering research lie in accurately understanding the mechanical impact of strain on *** paper first introduces the basic strategy for generating the strain,summarizes the different strain generation forms and their advantages and *** progress in researching the characterization means for the lattice strains and their applications in the field of electrocatalysis is also ***,the challenges of strain engineering are introduced,and an outlook on the future research directions is provided.

关键词： strain electrocatalysis characterization chemical reaction kinetics lattice mismatch

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Depositional Environment,Petrophysical Evaluation and electrical Properties of Zeit Formation,Northwestern Shore of Gulf of Suez,Egypt

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Journal of Earth Science 2024年第5期35卷 1720-1737页

作者： Mohamed M.gomaa Emad A.Abd el Aziz Geophysical Sciences Department National Research CentreEl-Behoos St.DokkiCairo 12622Egypt

The Zeit sand reservoir is one of the most prolific formations at Northwestern side of the Gulf of *** this research we will try to coordinate between electrical,petrophysical properties,depositional environment and facies discrimination in order to evaluate the hydrocarbon potentiality of studied Zeit *** statistical parameters for potassium(K),thorium(Th)and Th/U ratio contents have a general increase towards northwestern parts,whereas uranium(U)content has a general increase towards southeastern *** sandstone facies is distinguished from the other facies by its thorium content>4 ppm.U has high carbonate content(U≥1 ppm).Rocks'electrical properties vary greatly depending on a number of *** measurements were taken at frequencies range of(5×10^(-4)Hz-100 kHz)for fully saturated samples(clayey sandstone)with NaCl(20 gm/L).As salinity,clay content,and frequency increase,consequently does the electrical *** continental condition are present in northwestern part(back-sea)which is distinguished by high K percent,high Th,high Th/U ratio,and low U *** K,Th,and Th/U ratio contents,with high U contents,characterize the marine depositional environment that existed around the east and southeastern parts(foresea coincide with the dipping of strata).Furthermore,the studied Zeit Formation has good petrophysical properties that coincide with marine *** middle and eastern parts(around ISS-94 and CSS-288)is a good reservoir(porosity 36%-39%,shale content<15%,hydrocarbon saturation 71%-92%,and net pay thickness 17-63 feet).

关键词： Zeit Formation petrophysical evaluation depositional environment Spectral Gamma Ray electrical properties gulf of Suez sedimentology

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Ultralong hydroxyapatite-based forward osmosis membrane for freshwater generation

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Frontiers of Chemical Science and Engineering 2024年第9期18卷 37-49页

作者： Mohamed Gamal gomaa Hamdy Maamoun Abdel-Ghafar Francesco Galiano Francesca Russo Alberto Figoli el-Sayed Ali Abdel-Aal Abdel-Hakim Taha Kandil Bahaa Ahmed Salah Central Metallurgical Research and Development Institute(CMRDI) 11421 CairoEgypt Chemistry Department Faculty of ScienceHelwan University11795 CairoEgypt Institute on Membrane Technology(CNR-ITM) 87036 RendeItaly

Increasing global water shortages are accelerating the pace of membrane manufacturing,which generates many environmentally harmful *** challenges need a radical rethink of developing innovative membranes that can address freshwater production without generating environmentally harmful *** work utilized the synthesized ultra-long hydroxyapatite(UHA)by the solvothermal method using the green solvent oleic acid in preparing UHA-based forward osmosis *** membranes were developed using different loading ratios of graphene oxide(GO)by vacuum-assisted filtration *** prepared GO/UHA membranes were identified using X-ray diffraction,scanning electron microscope,Fourier-transform infrared spectroscopy,and X-ray photoelectron *** contact angle and pore size distribution were determined for the obtained GO/UHA *** obtained hierarchical porous structure in the prepared membranes with interconnected channels results in a stable water flux with reverse salt *** best water flux rate of 42±2 L·m^(–2)·h^(–1)was achieved using the 50 mg GO/UHA membrane,which is 3.3 times higher than the pristine membrane,and a reverse salt flux of 67 g·m^(-2)·h^(–1).The obtained results showed a promising capability of a new generation of sustainable inorganic-based membranes that can be utilized in freshwater generation by energy-efficient techniques such as forward osmosis.

关键词： forward osmosis ultra-long hydroxyapatite graphene oxide inorganic-based membrane

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Regulating electrochemical performances of lithium battery by external physical field

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Rare Metals 2024年第6期43卷 2391-2417页

作者： Shi-Kang Wang Shuai Wu Yi-Cheng Song Hassanien gomaa Cui-Hua An Qi-Bo Deng Ning Hu School of Mechanical Engineering School of Materials Science and EngineeringHebei University of TechnologyTianjin 300401China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai 200444China Department of Chemistry Faculty of ScienceAl-Azhar UniversityAssiut 71524Egypt Tianjin Key Laboratory of Power Transmission and Safety Technology for New Energy Vehicles Tianjin 300401China State Key Laboratory of Reliability and Intelligence electrical Equipment Key Laboratory of Advanced Intelligent Protective Equipment TechnologyMinistry of EducationHebei University of TechnologyTianjin 300130China

Lithium batteries have always played a key role in the field of new energy ***,non-controllable lithium dendrites and volume dilatation of metallic lithium in batteries with lithium metal as anodes have limited their ***,a large number of studies have shown that the electrochemical performances of lithium batteries can be enhanced through the regulation of external physical ***,it significantly hinders the growth of lithium dendrites and promoting the reaction *** review summarizes recent innovations in the investigation of various physical fields of lithium *** application of magnetic field in the synthesis of lithium battery electrode materials is *** influence factors and regulation mechanism of various physical fields on the electrochemical performance of lithium batteries are reviewed *** addition,the current research status and existing challenges,along with future directions for the evolution of lithium batteries,are minutely discussed and *** strategies for the further evolution of lithium batteries have also been provided.

关键词： Lithium battery External field assist Reaction kinetics Lithium dendrite

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Optimization of double chamber microbial fuel cell for domestic wastewater treatment and electricity production

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燃料化学学报 2015年第9期43卷 1092-1099页

作者： Amr el-Hag Ali Ola M.gomaa Reham Fathey Hussein Abd el Kareem Mohamed Abou Zaid Polymer Chemistry Department Microbiology Department National Center for Radiation Research and Technology (NCRRT) Egyptian Atomic energy Authority ( EAEA ) Nasr City Cairo Egypt DAS Taibah University Medinah KSA

Microbial fuel cells(M FCs)represent a new approach for treating w aste w ater along w ith electricity *** present study addressed electricity production from domestic w astew ater using a mediator-less double chamber M *** electricity production w as monitored under different operational conditions for both summer and w inter *** of the anodic and cathodic chambers resulted in a maximal current of 0.784 and 0.645 m A w ith the maximal pow er intensity of 209 and 117 m W/m2in pow er duration of 24 h for the summer and w inter samples,*** electron microscopy show ed that the bacterial biofilm formation on the anode w as denser for the summer sample than that w hen the w inter sample w as used,so w as the total bacterial ***,samples taken during summer w ere considered better in electricity production and w aste w ater treatment than those taken during w inter basically because of the high microbial load during the hot *** parallel,there w as a decrease in both biological oxygen demand(BOD5)and chemical oxygen demand(COD)values which reached 71.8%and 72.85%,respectively at the end of the operation process for the summer sample,w hile there w as no evident decrease for the w inter *** the operating conditions not only increased the potential of using domestic w aste w ater in microbial fuel cells to produce electricity,but also improved the quality of the domestic w aste w ater.

关键词：微生物引起的燃料房间国内废水处理操作条件电生产

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The vitreomacular interface in different types of agerelated macular degeneration

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International Journal of Ophthalmology(English edition) 2017年第2期10卷 246-253页

作者： Mohamed Abd elM onaem el-Hifnawy Hisham Ali Ibrahim Amir Ramadan gomaa Mohamed A elmasry Ophthalmology Department Alexandria University Faculty of MedicineKhartoum SquareAzaritaAlexandria 21526Egypt

AIM： To evaluate the vitreomacular interface in cases with wet age-related macular degeneration（AMD） and to compare them to eyes with dry AMD and normal ***： This was a cross-sectional comparative study that included 87 eyes with wet AMD,42 eyes with dry AMD and 40 eyes without AMD as a control *** coherence tomography（OCT） examination was performed for all patients to assess the vitreomacular ***： In the wet AMD group,34.5% of cases had vitreomacular adhesion（VMA）.Only 14.3% of dry AMD cases and 10% of control cases had *** was a significant difference between the control group and the wet AMD group（P=0.004） as well as the dry and wet AMD group（P=0.017）.There was also a significant difference between the incidence of VMA in patients with subretinal choroidal neovascularization（CNV,type 1） and intraretinal CNV（type 2 or type 3）（P=0.020）.CONCLUSION： There is an association between posterior vitreous attachment and *** is also an increased incidence of VMA with intra-retinal CNV.

关键词： age-related macular degeneration vitreomacular interface optical coherence tomography macula

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