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中华高血压杂志 2016年第8期24卷 799-799页

作者： Nielsen OW Sajadieh A sabbah m Greve Am Olsen mH Boman K Nienaber CA Kes?niemi YA Pedersen TR Willenheimer R Wachtell K 刘莉叶鹏

无症状的主动脉瓣狭窄（aortic valve stenosis，AS）患者的高血压治疗研究较少。研究人员获取依折麦布辛伐他汀治疗主动脉瓣狭窄（the simvastatin ezetimibe in aortic stenosis, SEAS）研究的试验数据，来评估该类疾病患者的最佳血... 详细信息

无症状的主动脉瓣狭窄（aortic valve stenosis，AS）患者的高血压治疗研究较少。研究人员获取依折麦布辛伐他汀治疗主动脉瓣狭窄（the simvastatin ezetimibe in aortic stenosis, SEAS）研究的试验数据，来评估该类疾病患者的最佳血压水平。

关键词：主动脉瓣狭窄无症状高血压患者 simvastatin 评估 ezetimibe aortic

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Strength and Wear Behavior of mg Alloy AE42 Reinforced with Carbon Short Fibers

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Acta metallurgica Sinica(English Letters) 2019年第1期32卷 31-40页

作者： sabbah Ataya Naser A.Alsaleh mohamed m.El-Sayed Seleman metallurgical and materials Engineering Department Faculty of Petroleum and Mining Engineering Suez University Department of mechanical Engineering College of Engineering Al Imam Mohammad Ibn Saud University

In addition to the advantage of the lightweight of magnesium alloys, magnesium composites have moderate strength and elastic modulus. The proposed application of magnesium composites as diesel truck pistons makes it necessary to assess their wear performance. Little research data have been discussed on wear behavior of mg alloy AE42 matrix and its composites. Thus, this paper reports wear behavior of magnesium alloy AE42(mg–Al–mn—RE; rare earth) and its composite AE42-C, which contains 23 vol% of randomly oriented carbon short fibers. materials characterization, including density measurements, hardness testing, microstructures investigation, and compression testing at temperatures of 25, 150,and 300 °C, were conducted. Wear tests were performed under various loads and sliding distances. Wear mechanisms were also proposed based on the examination of worn surfaces using optical microscopy and scanning electron microscopy equipped with EDX(energy-dispersive X-ray spectrometry) analysis system. The hardness of AE42-23 vol% C composite is twice the hardness of the mg matrix alloy AE42. Significant improvements to yield stress and compressive strength at temperatures of 25, 150, and 300 °C of the composite versus the AE42 alloy are achieved. Wear resistance of the composite is improved considerably versus that of the mg alloy AE42 at the various sliding distances. Smearing of graphite on the worn surface produces a lubricating film that delays change from mild to severe wear of the composite, especially at high loads. EDX analysis of the worn surface shows oxidation of the matrix alloy at higher wear loads, and this mechanism decreases in the presence of carbon fibers under the same loads. Abrasive wear, oxidation, and plastic deformation are the dominant wear mechanisms for the alloy matrix AE42, whereas mainly abrasive wear is the wear mechanism of AE42-23 vol% C composite under the proposed testing conditions.

关键词： magnesium composites Carbon short fibers Compressive strength Wear resistance Wear mechanisms

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microstructure and mechanical properties of hot extruded 6016 aluminum alloy/graphite composites

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Journal of materials Science & Technology 2018年第9期34卷 1580-1591页

作者： mohamed m.El-Sayed Seleman mohamed m.Z.Ahmed sabbah Ataya Department of metallurgical and materials Engineering Faculty of Petroleum and Mining Engineering Suez University 43518 Suez Egypt Suez and Sinai metallurgical and materials Research Center of Scientific Excellence (SSmmR-CSE) 43518 Suez Egypt The British University in Egypt Mechanical Engineering Deportment El-Sherouk City 11837 Cairo Egypt Department of mechanical Engineering College of Engineering AI Imam Mohammad Ibn Saud Islamic University Riyadh 11432 saudi Arabia

The incorporation of graphite particles into AA6016 aluminum alloy matrix to fabricate metal/ceramic composites is still a great challenge and various parameters should be considered. In this study, dense AA6016 aluminum alloy/（0-20 wt%） graphite composites have successfully been fabricated by powder metallurgy process. At first, the mixed aluminum and graphite powders were cold compacted at 200 mPa and then sintered at 500 ℃ for 1 h followed by hot extrusion at 450 ℃. The influence of ceramic phases（free graphite and in-situ formed carbides） on microstructure, physical and mechanical properties of the produced composites were finally investigated. The results show that the fabricated composites have a relative density of over 98%. SEm observations indicate that the graphite has a good dispersion in the alloy matrix even at high graphite content. Hardness of all the produced composites was higher than that of aluminum alloy matrix. No cracks were observed at strain less than 23% for all hot extruded *** strength, reduction in height, ultimate tensile stress, fracture stress, yield stress, and fracture strain of all Al/graphite composites were determined by high precision second order equations. Both compressive and ultimate tensile strengths have been correlated to microstructure constituents with focusing on the in-situ formed ceramic phases, silicon carbide（SiC） and aluminum carbide（Al4 C3）. The ductile fracture mode of the produced composites became less dominant with increasing free graphite content and in-situ formed carbides. Wear resistance of Al/graphite composites was increased with increasing graphite content. Aluminum/20 wt% graphite composite exhibited superior wear resistance over that of AA6016 aluminum alloy.

关键词： AA6016/graphite composites Hot extrusion In-situ carbides mechanical properties Wear resistance Fracture behavior

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Vitamin D Receptor Expression in Lumbar Disc Degeneration Patients

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Open Journal of modern Neurosurgery 2017年第2期7卷 19-33页

作者： mahmoud m. Taha Norhan A. sabbah Noha A. Rezk Hosam mansour Neurosurgery Department Faculty of Medicine Zagazig University Zagazig Egypt medical Biochemistry Department Faculty of Medicine Zagazig University Zagazig Egypt Radiology Department Faculty of Medicine Zagazig University Zagazig Egypt

Background: Lumbar disc degeneration [LDD] is the main cause of low back pain, and is a medical circumstance that poses a great load on the global health care system with serious socioeconomic consequences. The aim of this study was to determine the association of vitamin D receptors (VDR) gene Fok1 polymorphism, VDR expression and vitamin D level with LDD susceptibility and severity in Egyptians. materials and methods: A total of unrelated 169 female patients with low back pain diagnosed as having lumbar disc degeneration and 169 controls were enrolled in the study. VDR Fok1 polymorphism was determined using restriction fragment length polymorphism-polymerase chain reaction [PCR-RFLP]. VDR expression was measured by reverse transcriptase PCR, while, serum levels of vitamin D were measured by high performance liquid chromatography [HPLC]. Results: Subjects with VDR Fok1 ff genotype were significantly more likely to develop LDD in Egyptians and associated with multilevel disc degeneration and disc herniation (adjusted OR = 7.9, 95% CI = 2.3-26.6 and P = 0.01) and (adjusted OR = 2.2, 95% CI = 1.6-3.7 and P = 0.031) respectively. VDR expression and vitamin D levels were significantly decreased in LDD patients and with multilevel disc degeneration and herniation, (adjusted P = 0.042 and adjusted P = 0.028) respectively. Conclusion: VDR Fok1 mutant alleles and genotypes are associated with the development and severity of LDD in Egyptians. Also, VDR expression and vitamin D level could be the marker for monitoring LDD.

关键词： Lumbar Disc Vitamin D Degeneration Polymorphism PCR

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A micro-Sized Light-Driven Pico-Second Oscillator

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Journal of Applied mathematics and Physics 2020年第12期8卷 2793-2800页

作者： Ali J. sabbah R. Hamam math and Physics Department Lebanese International University Beirut Lebanon

Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects such as solar sails, among many other important applications. While these efforts benefit from the average value of light’s linear momentum, in this article, we propose exploiting the temporal variation of light’s linear momentum to achieve an oscillatory force of microNewton amplitude and picosecond period. We validate our proposal by analytical calculations and time domain simulations of maxwell’s equations in the case of a high-index quarter-wave slab irradiated by a terahertz plane electromagnetic wave. In particular, we show that for plane wave terahertz light of electric field amplitude 5000 V/m and frequency 4.8 THz, an oscillatory radiation pressure of amplitude 1.8 × 10-4 N/m2 and 0.1 ps period can be achieved.

关键词： Radiation Force Optical manipulation/micromachines Instantaneous Electromagnetic Linear momentum Density Linear momentum Conservation Light Driven Oscillator

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Electroless Plating Lead and Lead-Tin on Copper Using an Eco-Friendly Plating Bath

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materials Sciences and Applications 2020年第12期11卷 867-879页

作者： A. B. Abdel-Aziz m. m. B. El-sabbah I. m. Ghayad Adham A. El-Zomrawy October High Institute for Engineering & Technology Giza Governorate Egypt Chemistry Department Faculty of Science Al-Azhar University Cairo Egypt Central metallurigical R & D Institute Cairo Egypt

Copper serpentines used in gas heaters are currently coated with lead-tin alloy using hot-dip technology where copper is immersed in molten lead (98%)-Tin at about 400°C. The major drawback of this technique is the pollution resulted from lead vapors which cause much harm to the labors in the unit. The present work investigates an eco-friendly plating technique to replace the currently used technology. Electroless plating of copper samples with lead or Lead (98%)-Tin alloy is carried out from a plating bath contained lead salt, tin salt, reducing agent and stabilizing agent. The parameters affecting the coating quality such as the plating time, temperature and bath composition were optimized. The chemical analysis and coating morphology of the formed coatings are examined by XRD, SEm and EDS to reach the best bath composition as well as the best conditions to coat copper with lead or lead-tin electrolessly. The electrochemical properties of copper and copper coated samples are also examined using electrochemical impedance spectroscopy.

关键词： Copper Serpentine Hot Dip Coating Lead-Tin Electro Plating Electroless Plating

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