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Friction 2020年第5期8卷 905-916页

作者： mohamed kamal ahmed ali Xianjun HOU mohamed AAABDELKAREEM Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Automotive and Tractors Engineering Department Faculty of EngineeringMinia UniversityEl-Minia 61111Egypt Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan 430070China

Owing to the significance of improving fuel economy, reducing emissions, and extending the durability of engine components, this study focused on the tribological performance of nano-additives. In this study, copper (Cu) and graphene (Gr) nanomaterials were dispersed in a fully formulated engine oil (5W-30) with different concentrations. The tribological trials were investigated under various speeds and loads, utilizing a reciprocating tribometer to mimic the ring/liner interfaces in the engine. The frictional surface morphologies were com-prehensively analyzed using electron probe X-ray microanalysis (EPMA), field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), and three dimensional (3D) surface profilometry to explore the mechanisms responsible for improving the tribological performance of the frictional sliding parts in the engine. The tribological test results illustrated that lubrication by nano-additives reduced the wear rate (WR) and friction coefficient (COF) by 25%–30% and 26.5%–32.6%, respectively, as compared with 5W-30. The results showed that this is a promising approach for increasing the durability and lifespan of frictional sliding components and fuel economy in automobile engines.

关键词： engine tribology nanomaterial nanolubricant friction wear tribofilm

纳米润滑添加剂改善摩擦磨损提高发动机性能的研究

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润滑与密封 2018年第6期43卷 1-5页

作者：侯献军王士成 mohamed kamal ahmed ali 现代汽车零部件技术湖北省重点实验室(武汉理工大学) 湖北武汉430070 汽车零部件技术湖北省协同创新中心湖北武汉430070

以5W-30润滑油为基础油,Al_2O_3/TiO_2为纳米添加剂,配制添加剂质量分数为2%的纳米润滑油。通过摩擦学性能试验台模拟缸套-活塞环摩擦副实际工作过程,研究Al_2O_3/TiO_2纳米添加剂对摩擦学性能的改善;通过场发射扫描电镜(FESEM)对活塞... 详细信息

以5W-30润滑油为基础油,Al_2O_3/TiO_2为纳米添加剂,配制添加剂质量分数为2%的纳米润滑油。通过摩擦学性能试验台模拟缸套-活塞环摩擦副实际工作过程,研究Al_2O_3/TiO_2纳米添加剂对摩擦学性能的改善;通过场发射扫描电镜(FESEM)对活塞环样本微观形貌进行观察,确定表面磨损情况;通过发动机台架实验研究确定实际使用工作过程中,纳米添加剂对发动机动力性能的影响。结果表明,润滑油中加入Al_2O_3/TiO_2纳米添加剂后,缸套-活塞环摩擦副摩擦磨损性能得到明显改善,摩擦因数和活塞环磨损率显著下降,摩擦因数最大下降50.6%,平均下降42%;活塞环磨损率最大下降34.8%,平均下降27.2%;活塞环表面微观形貌得到明显改善,磨损表面得到修复,划痕显著减少;在转速为4 400 r/min时随着负荷逐渐增大,发动机台架实验输出功率最高提升24.2%,低负荷功率增幅显著,高负荷范围内功率平均提升3.3%,动力性能得到较大提升。

关键词：润滑油纳米添加剂摩擦磨损

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缸套-活塞环摩擦学性能模拟实验研究

润滑与密封 2017年第3期42卷 8-11,17页

作者：侯献军陈必成蔡清平 mohamed kamal ahmed ali 彭辅明现代汽车零部件技术湖北省重点实验室(武汉理工大学) 湖北武汉430070 汽车零部件技术湖北省协同创新中心湖北武汉430070

为模拟内燃机缸套-活塞环运动,设计适用于缸套-活塞环的往复式摩擦性能试验台,由传动系统、加热系统、加载系统组成。根据系统中悬臂梁和活塞环专用夹具不同的使用要求,分别进行结构设计和有限元分析。结果表明,当实验条件达到预设极限... 详细信息

为模拟内燃机缸套-活塞环运动,设计适用于缸套-活塞环的往复式摩擦性能试验台,由传动系统、加热系统、加载系统组成。根据系统中悬臂梁和活塞环专用夹具不同的使用要求,分别进行结构设计和有限元分析。结果表明,当实验条件达到预设极限值(加热温度130℃,摩擦力500 N)时悬臂梁和活塞环专用夹具均能满足使用要求。试验台使用二维力测力传感器,通过特殊装配设计,可同时测量摩擦力和法向负载。通过摩擦性能实验验证,缸套-活塞环在较低负荷(61.7、92.6、123.4 N)条件下,摩擦因数随转速的增大而急剧减小;在较高负荷(250.8、322.5 N)条件下,摩擦因数随转速的增大有所减小并逐渐趋于稳定状态。

关键词：摩擦性能试验台结构设计缸套-活塞环摩擦因数

纳米TiO2和Al2O3添加剂润滑油对缸套-活塞环摩擦磨损性能的影响

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武汉理工大学学报（交通科学与工程版） 2017年第2期41卷 191-194页

作者：侯献军蔡清平陈必成 mohamed kamal ahmed ali 彭辅明现代汽车零部件技术湖北省重点实验室武汉430070 汽车零部件技术湖北省协同创新中心武汉430070 米尼亚大学工程学院米尼亚61111

以普通5W-30润滑油作为基础油,按一定配比添加纳米Al_2O_3和TiO_2粉末,通过实验台架高度模拟缸套-活塞环的工作环境,研究不同载荷下纳米添加剂润滑油对缸套-活塞环摩擦副摩擦磨损特性的影响.使用二分力拉压传感器和数据采集系统测量及... 详细信息

以普通5W-30润滑油作为基础油,按一定配比添加纳米Al_2O_3和TiO_2粉末,通过实验台架高度模拟缸套-活塞环的工作环境,研究不同载荷下纳米添加剂润滑油对缸套-活塞环摩擦副摩擦磨损特性的影响.使用二分力拉压传感器和数据采集系统测量及保存摩擦副的受力;用0.1mg精度电子天平测量摩擦前后活塞环的质量损失;用三维表面轮廓仪扫描试样表面形貌;用场发射扫描电镜对样本进行微观观察及能谱分析.实验结果表明,纳米Al_2O_3和TiO_2添加剂润滑油能够显著的改善缸套-活塞环摩擦副的摩擦磨损性能,同5W-30基础油相比,纳米Al_2O_3润滑油使摩擦副的摩擦因数和磨损率分别降低48.5%和21.6%,而纳米TiO_2润滑油则分别降低49.9%和37.6%,表面平整度及表面磨痕也相应得到改善.

关键词：缸套-活塞环纳米Al2O3 纳米TiO2 摩擦磨损

Al_2O_3/TiO_2纳米复合粉体的摩擦学性能研究

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化工新型材料 2017年第9期45卷 127-129页

作者：侯献军陈必成蔡清平 mohamed kamal ahmed ali 彭辅明现代汽车零部件技术湖北省重点实验室(武汉理工大学) 武汉430070 汽车零部件技术湖北省协同创新中心武汉430070

将油酸和硅烷偶联剂(KH-560)修饰的Al_2O_3/TiO_2纳米复合粉体添加到基础油中,用可见分光光度计表征纳米粒子在润滑油中的分散稳定性,在自主设计的摩擦磨损试验机上考察Al_2O_3/TiO_2纳米复合粉体作为润滑油添加剂的抗磨减摩性能,用3D... 详细信息

将油酸和硅烷偶联剂(KH-560)修饰的Al_2O_3/TiO_2纳米复合粉体添加到基础油中,用可见分光光度计表征纳米粒子在润滑油中的分散稳定性,在自主设计的摩擦磨损试验机上考察Al_2O_3/TiO_2纳米复合粉体作为润滑油添加剂的抗磨减摩性能,用3D表面轮廓仪、扫描电镜和电子能谱分析试样表面形貌与成分变化及纳米粒子的作用机理。结果表明:在0.25%Al_2O_3/TiO_2纳米复合粉体(Al_2O_3∶TiO_2=1∶1)润滑油中添加2%KH-560时,具有最好的分散稳定性;在润滑油中添加0.25%Al_2O_3/TiO_2纳米复合粉体(Al_2O_3∶TiO_2=1∶1)时抗磨减摩效果最佳,在载荷500N、转速1100r/min时,摩擦系数和磨损量相比基础油时分别降低25.4%和43.8%。

关键词：硅烷偶联剂 Al2O3/TiO2纳米复合粉体抗磨减摩自修复作用

边界润滑条件下机油污染物对摩擦学性能的影响

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润滑与密封 2017年第2期42卷 1-5页

作者： mohamed kamal ahmed ali FAWZY M.H.Ezzat 侯献军陈必成蔡清平现代汽车零部件技术湖北省重点实验室(武汉理工大学) 湖北武汉430070 米尼亚大学工程学院米尼亚61111 汽车零部件技术湖北省协同创新中心湖北武汉430070

选用Fe、Cu、Al、Pb、SiO_2固体颗粒作为机油污染物,在模拟的发动机缸套-活塞环往复运动实验台上,研究边界润滑条件下固体污染物含量和尺寸对机油摩擦学性能的影响。实验结果表明:机油中的固体颗粒物导致摩擦因数和摩擦功损失增加,同时... 详细信息

选用Fe、Cu、Al、Pb、SiO_2固体颗粒作为机油污染物,在模拟的发动机缸套-活塞环往复运动实验台上,研究边界润滑条件下固体污染物含量和尺寸对机油摩擦学性能的影响。实验结果表明:机油中的固体颗粒物导致摩擦因数和摩擦功损失增加,同时增加摩擦副接触面的表面粗糙度;摩擦因数、摩擦功损失、磨损量均随污染物含量、颗粒物尺寸的增加而增加,其中铁粒子污染物影响最大,铜次之,铅的影响最小;固体颗粒物会降低发动机性能,增加燃油消耗,为降低固体颗粒物对机油的影响,必须提高机油过滤精度。

关键词：固体污染物机油边界润滑摩擦磨损

Summary of the current guidelines for managing iatrogenic colorectal perforations and the evolving role of endoluminal vacuum therapy

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World Journal of Clinical Cases 2025年第6期13卷 1-8页

作者： ahmed Tawheed Ibrahim Halil Bahcecioglu Mehmet Yalniz Mubin Ozercan ali Cagri Oral mohamed El-Kassas Department of Endemic Medicine Faculty of MedicineHelwan UniversityCairo 11795Egypt Department of Gastroenterology Firat UniversityElazig 23119Türkiye Liver Disease Research Center College of MedicineKing Saud UniversityRiyadh 7805Saudi Arabia

Colonoscopy represents a safe procedure that is widely used in medical practice either to diagnose or treat various gastrointestinal *** the last few years,the incidence rate of perforations in colonoscopic procedures has increased,especially in therapeutic *** recent advancements in endoscopic techniques and gastrointestinal tumoral resection procedures such as endoscopic mucosal resection,endoscopic full-thickness resection,and endoscopic submucosal dissection(ESD)could be a risk factor for this increased *** incidence rate of mortality of serious colonoscopic perforations is 7.1%.The management plan for these perforations starts with conservative treatment in mild cases,endoscopic closure,and surgical management in severe ***,endoluminal vacuum therapy was found to be effective in the management of colorectal perforations and this has been reported in multiple case *** editorial provides an overview of the current guidelines for the management of iatrogenic colorectal *** insights are from the perspectives of endoscopists and *** also present a management algorithm based on the guidelines of the European Society of Gastrointestinal Endoscopy,the American Gastroenterological Association,and the World Society of Emergency *** also discussed in brief the use of endoluminal vacuum therapy in colorectal perforations.

关键词： Colon Rectum Iatrogenic colonic perforation Colonoscopy Guidelines Endovacuum Endolumical vacuum therapy Endoscopic management

Atezolizumab and bevacizumab combination in advanced hepatocellular carcinoma patients:The imperative for safety assessment studies

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World Journal of Clinical Cases 2025年第9期13卷 56-59页

作者： Mina Tharwat ahmed Tawheed mohamed El-Kassas Department of Tropical Medicine and Gastroenterology Faculty of MedicineAswan UniversityAswan 81528Egypt Department of Endemic Medicine Faculty of MedicineHelwan UniversityCairo 11795Egypt

Hepatocellular carcinoma(HCC)is the most prevalent cancer of the hepatobiliary tract and the third leading cause of cancer-related mortality *** and bevacizumab combination is currently considered among the frontline treatment modalities for advanced unresectable *** studies examining this combination were focused on evaluating its *** numerous case reports documenting some side effects,there is a limited number of large-scale studies assessing these side *** this article,we comment on the case report by Park et al published recently,reporting a fatal intra-tumoral hemorrhage in a patient with HCC who received systemic therapy in the form of the combination of atezolizumab and bevacizumab.

关键词： Hepatocellular carcinoma Atezolizumab Bevacizumab Hemorrhage Side effects

Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling Systems

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Structural Durability & Health Monitoring 2025年第1期19卷 77-103页

作者： Sabrina Meddah Sid ahmed Tadjer Abdelhakim Idir Kong Fah Tee mohamed Zinelabidine Doghmane Madjid Kidouche Applied Automation Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering Department Mohamed Boudiaf University of M’silaM’sila28000Algeria Department of Civil and Environmental Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building Materials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is *** study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm to the system’s components since they are difﬁcult to be detected and controlled in real *** study investigates the dynamic interactions of these vibrations,speciﬁcally in their high-frequency modes,usingﬁeld data obtained from measurement while ***ﬁndings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem *** obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control ***,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect ***,by exploiting theseﬁndings,the assessment of structural resilience in rotary drilling systems can be ***,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efﬁciency of rotary drilling systems in the petroleum industry.

关键词： Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis ﬁeld data analysis

Gut virome:New key players in the pathogenesis of inflammatory bowel disease

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World Journal of Methodology 2025年第2期15卷 27-43页

作者： Helal F Hetta Rehab ahmed Yasmin N Ramadan Hayam Fathy Mohammed Khorshid mohamed M Mabrouk Mai Hashem Department of Medical Microbiology and Immunology Faculty of MedicineAssiut UniversityAssiut 71515Egypt Division of Microbiology Immunology and BiotechnologyFaculty of pharmacyUniversity of TabukTabuk 71491Saudi Arabia Division of Microbiology Immunology and BiotechnologyDepartment of Natural Products and Alternative MedicineFaculty of PharmacyUniversity of TabukTabuk 71491Saudi Arabia Department of Internal Medicine Division HepatogastroenterologyAssiut UniversityAssiut 71515Egypt Department of Clinical Research Egyptian Developers of Gastroenterology and Endoscopy FoundationCairo 11936Egypt Department of Internal Medicine Faculty of Medicine.Tanta UniversityTanta 31527Egypt Department of Tropical Medicine Gastroenterology and HepatologyAssiut University HospitalAssiut 71515Egypt

Inflammatory bowel disease(IBD)is a chronic inflammatory illness of the *** the mechanism underlying the pathogenesis of IBD is not fully under-stood,it is believed that a complex combination of host immunological response,environmental exposure,particularly the gut microbiota,and genetic suscept-ibility represents the major *** gut virome is a group of viruses found in great frequency in the gastrointestinal tract of *** gut virome varies greatly among individuals and is influenced by factors including lifestyle,diet,health and disease conditions,geography,and *** majority of research has focused on the significance of gut bacteria in the progression of IBD,although viral populations represent an important component of the *** conducted this review to highlight the viral communities in the gut and their expected roles in the etiopathogenesis of IBD regarding published research to date.

关键词： Inflammatory bowel disease Pathogenesis Gut virome Bacteriophage Eukaryotic viruses