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Thermomechanical Analysis of (Cu_(0.5)Tl_(0.5))-1223 Substituted by Pr and La

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Journal of Materials Science & Technology 2012年第2期28卷 169-176页

作者： A.i.Abou Aly R.Awad i.h.ibrahim M.Kamal M.Anas Physics Department Faculty of ScienceAlexandria University Physics Department Faculty of ScienceMansoura University

The thermomechanical analysis （TMA） of Cu0.5T10.5Ba2Ca2-xRxCu30110-δ, where R=Pr and La, with 0.0〈x〈0.15, was carried out in temperature range from 450 to 1145 K. The samples were prepared by singlestep solid state reaction technique. The prepared samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The superconductivity of the prepared samples was investigated by electrical resistivity measurement. The results showed that low substitution content enhanced the （Cu0.5Tlo.5）- 1223 phase formation, while the higher substitution content degraded this phase. The higher superconducting transition temperatures Tc were found to be 114 K and 109 K at x= 0.025 for Pr- and La-substitutions, respectively. The average linear thermal expansion coefficient increased as x increased, while the shrinkage temperature decreased as x increased. Those results were emphasized by porosity and Vickers microhardness calculations. Debye temperature 0D was calculated from the linear thermal expansion coefficient data and correlated to Tc to estimate the electron-phonon coupling λep.

关键词： (Cu0.5Tl0.5)-1223 Thermomechanical analysis Thermal expansion coefficient Debye temperature

Electrical and mechanical properties of (Bi, Pb)-2223 substituted by holmium

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Journal of Advanced Ceramics 2016年第1期5卷 54-69页

作者： W.ABDEEN S.MARAhBA R.AWAD A.i.ABOU ALY i.h.ibrahim M.MATAR Superconductivity and Metallic Glass Lab Physics Department Faculty of ScienceAlexandria University Alexandria EgyptPhysics Department University College at Al-Gamom Umm Al-Qura University Saudi Arabia Physics Department Faculty of Science Beirut Arab University(BA U) Beirut Lebanon Superconductivity and Metallic Glass Lab Physics Department Faculty of ScienceAlexandria University Alexandria Egypt

The effect of the partial substitution of Ca2+ by ho3+ ions on the electrical and mechanical properties of the superconducting phase (Bi,Pb)-2223 was studied. Superconducting samples of the type (Bi1.8Pb0.4)Sr2Ca2.1?x ho xCu3.1O10+δ were prepared by solid-state reaction technique under ambient pressure, and characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The superconducting transition temperature T c and pseudogap temperature T* were estimated from electrical resistivity measurements, while the critical current density J c was determined from i-V curves. The electrical resistivity data were discussed according to bipolaron model in the absence of thermally excited individual polarons. The sample with x = 0.025 showed the highest phase volume fraction, T c, and J c. Room temperature Vickers microhardness measurements were carried out at different applied loads (0.25-5 N) in order to investigate the performance of the mechanical properties of (Bi1.8Pb0.4)Sr2Ca2.1?x ho xCu3.1O10+δ phase. it was found that all the samples exhibit normal indentation size effect (iSE). The Vickers microhardness number h V increased as x increased from 0 to 0.025. The experimental results were discussed in view of Meyer’s law, hays-Kendall (hK) approach, elastic/plastic deformation (EPD) model, and proportional specimen resistance (PSR) model. The load independent (true) microhardness of (Bi1.8Pb0.4)Sr2Ca2.1?x ho xCu3.1O10+δ superconducting samples showed identical behavior to that of the PSR model.

关键词： (Bi,Pb)-2223 phase ho substitution Vickers microhardness bipolaron model pesudogap temperature

Arctic sea-ice extent: No record minimum in 2023 or recent years

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Atmospheric and Oceanic Science Letters 2025年第1期18卷 52-55页

作者： Ola M.Johannessen Tor i.Olaussen Nansen Scientific Society BergenNorway Nansen Environmental and Remote Sensing Center BergenNorway

Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(***^(2)). This was not a record low, which occurred in 2012, when the minimum was 4.175 ***^(2), 0.794 ***^(2) less than the minimum in 2023. however, the ice extent had decreased by 0.432 ***^(2) compared with 2022. Nevertheless, the summer melting in 2023 was remarkably less than expected when considering the strong heat waves in the atmosphere and ocean, with record temperatures set around the world. in general, there is a high correlation between the long-term decrease in sea-ice extent and the increasing CO_(2) in the atmosphere, where the increase of CO_(2) in recent decades explains about 80% of the decrease in sea ice in September, while the remainder is caused by natural variability.

关键词： Sea ice Arctic Minimum ice Climate

Effect of graphene addition on the physicomechanical and tribological properties of Cu nanocomposites

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international Journal of Minerals,Metallurgy and Materials 2022年第1期29卷 161-167页

作者： Adnan i.Khdair A.ibrahim Mechanical Engineering Department Faculty of EngineeringKing Abdulaziz UniversityP.O.Box 80204JeddahSaudi Arabia Jordan University of Science and Technology Mech.Eng.Dep.P.O.Box 3030Irbid 2011Jordan higher Technological institute Tenth of Ramadan CityEgypt

This paper presents an experimental investigation of the mechanical and tribological properties of Cu-graphene nanosheets(GN)*** employed the electroless coating process to coat GNs with Ag particles to avoid its reaction with Cu and the formation of intermetallic *** analyzed the effect of GN content on the structural,mechanical,and tribological properties of the produced *** showed that the electroless coating process is an efficient technique to avoid the reaction between Cu and C and the formation of intermetallic *** addition of GNs significantly improves the mechanical and tribological properties of Cu ***,the addition of GNs needs to be done carefully because,after a certain threshold value,the mechanical and tribological properties are negatively *** optimum GN content is determined to be 0.5vol%,at which hardness,wear rate,and coefficient of friction are im-proved by 13%,81.9%,and 49.8%,respectively,compared with Cu *** improved properties are due to the reduced crys-tallite size,presence of GNs,and homogenous distribution of the composite constituents.

关键词： copper graphene nanosheets coating mechanical properties wear

Comparison of impact Properties for Carbon and Low Alloy Steels

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Journal of Materials Science & Technology 2011年第10期27卷 931-936页

作者： O.h.ibrahim Metallurgy Dept. Nuclear Research CentreAtomic Energy Authority

The impact properties of hot rolled carbon steel （used for the manufacture of reinforcement steel bars） and the quenched ＆ tempered （Q＆T） low alloy steel （used in the pressure vessel industry） were determined. The microstructure of the hot rolled carbon steel contained ferrite/pearlite phases, while that of the quenched and tempered low alloy steel contained bainite structure. impact properties were determined for both steels by instrumented impact testing at temperatures between -150 and 200℃. The impact properties comprised total impact energy, ductile to brittle transition temperature, crack initiation and propagation energy, brittleness transition temperature and cleavage fracture stress. The Q＆T low alloy steel displayed much higher resistance to ductile fracture at high test temperatures, while its resistance to brittle fracture at low test temperatures was a little higher than that of the hot rolled carbon steel. The results were discussed in relation to the difference in the chemical composition and microstructure for the two steels.

关键词： Ferritic/pearlitic steel Bainitic steel impact properties

Structural, M?ssbauer spectroscopy, magnetic properties, and thermal measurements of Y(3-x)Dy_x Fe_5O_(12)

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Chinese Physics B 2018年第10期27卷 558-564页

作者： Mahdi Lataifeh Qassem i Mohaidat Sami h Mahmood ibrahim Bsoul Mufeed Awawdeh ibrahim Abu-Aljarayesh Mu'ath Altheeba Physics Department Yarmouk University Irbid 21163 Jordan Physics Department The University of Jordan Amman 11942 Jordan Physics Department AI al-Bayt University Mafraq 13040 Jordan

Yttrium iron garnet powder samples（Y3-xDyxFe5O12）, where part of yttrium ions are substituted by dysprosium ions with different concentrations are prepared by the solid state reaction method. The properties of the prepared samples are examined by different methods such as x-ray diffraction（XRD）, Mssbauer spectroscopy, macroscopic magnetization measurements, and thermal measurements. The XRD measurements show that all the samples reveal the presence of a single garnet phase with a BCC structure. Room temperature Mssbauer spectra indicate that iron ions occupy three magnetic sites, i.e., two octahedral sites and one tetrahedral site. The saturation magnetization and the initial magnetic susceptibility decrease with the increase of Dy^3＋ substitution. The Curie temperature obtained from the thermal measurements seems to be independent of Dy^3＋ substitution.

关键词： Mossbauer spectroscopy magnetic properties x-ray diffraction differential scanning calorimetry

Neuroinflammation as a therapeutic target in huntington's disease

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Neural Regeneration Research 2025年第3期20卷 817-818页

作者： Andrea Kwakowsky Thulani h.Palpagama Center for Brain Research and Department of Anatomy and Medical imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CentreUniversity of GalwayGalwayIreland

in 1872, George huntington presented his essay “On Chorea” to the Meigs and Mason Academy of Medicine and, in doing so, detailed a disease that would later bear his name. huntington's disease(hD) is a genetic, neurodegenerative disease that manifests as the loss of motor control,cognitive impairment,and mood and psychiatric changes in paents.

关键词： huntington inflammation Medicine

Glial response in the midcingulate cortex in huntington’s disease

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Neural Regeneration Research 2025年第1期20卷 207-208页

作者： Thulani h.Palpagama Andrea Kwakowsky Center for Brain Research and Department of Anatomy and Medical imaging Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand Pharmacology and Therapeutics School of MedicineGalway Neuroscience CenterUniversity of GalwayGalwayIreland

huntington’s disease(hD)is a genetic disease characterized by the progressive degeneration of the striatum and *** can present with a variety of symptoms that can broadly be classified into motor symptoms,inclusive of choreatic movements and rigidity,mood and psychiatric symptoms,such as depression and apathy,and cognitive symptoms,such as cognitive *** causal mutation underlying hD results from an expansion of a CAG repeat sequence on the iT15 gene,resulting in the formation and accumulation of a mutant huntingtin protein.

关键词： huntington degeneration cortex

Coarse to Fine: The Role of Severe Plastic Deformation in Advancing Titanium-Based Medical implants - A Comprehensive Review

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 295-306页

作者： Dragana R Mihajlović Bojan i Međo ivana Lj Cvijović-Alagić Veljko R Djokić Faculty of Technology and Metallurgy University of BelgradeKarnegijeva 411120 BelgradeSerbia Vinča institute of Nuclear Sci-ences-National institute of the Republic of Serbia University of Belgrade11001BeogradSerbia innovation Centre of the Faculty of Technology and Metallurgy Karnegijeva 411120 BelgradeSerbia

This paper describes severe plastic deformation(SPD)procedures,which are utilized to form an ultrafine-grained structure in metallic *** the SPD process,a solid material sample is subjected to very high loads without a significant change in sample *** the present work,the high-pressure torsion(hPT)process,as one of the SPD techniques,which achieves a high degree of deformation and ensures refinement of the microstructure,will be discussed in more *** that grain size control is accepted as a method to obtain materials with desired characteristics,an overview of the properties of ultrafine-grained titanium-based biomaterials to be used in medicine is ***,particular attention is dedicated to the influences of hPT process parameters,primarily hydrostatic pressure,and number of revolutions during torsion,on the grain size and physical and mechanical characteristics(modulus of elasticity,microhardness,and tensile properties),corrosion resistance,and biocompatibility of the titanium-based biomaterials.A review of the literature indicates that titanium-based materials obtained by the SPD process show improved mechanical and physical properties without losing biocompatibility and corrosion resistance,which suggests that these methods of obtaining implants are something that should be further developed in the future.

关键词： high-pressure torsion process ultrafine-grained titanium-based materials electrochemical anodization physical properties mechanical properties