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作者： alanazi hani owaid s 华南理工大学

学位级别：硕士

在2019年,中国提出了“新基建”规划,特高压作为所提的七大建设领域之一,受到了中国政府的特别关注。高压输电塔作为特高压领域中的关键部分,是整个高压电力系统中电能的载体,具有十分重要的地位。输电电压等级的提高直接导致了输电塔... 详细信息

在2019年,中国提出了“新基建”规划,特高压作为所提的七大建设领域之一,受到了中国政府的特别关注。高压输电塔作为特高压领域中的关键部分,是整个高压电力系统中电能的载体,具有十分重要的地位。输电电压等级的提高直接导致了输电塔的高度也随之增加,而现有研究对此缺乏量化分析,这对其耗材、承载能力和优化设计提出了新要求。因此,有必要对高压输电塔的结构与稳定性进行研究,以便适应新型电力系统的大容量电量运送需求。本文的主要研究内容和创新如下:依据高压输电塔输电线的构造原理,对输电塔塔架、输电线和绝缘子串进行造型,建立了在自重和水平张力作用下的塔-线初始状态模型及其动力特性。在此基础上,选用梁单元模拟塔架、受拉力单元模拟输电线和刚性杆模拟绝缘子串,通过有限元软件Midas Gen建立有限元模型,进而对输电塔和输电线进行动力特性模拟。以高压输电塔的空间桁架模型、空间刚架模型和空间梁桁组合模型为对象,基于弹塑性增量法和弹性模量缩减法对超高压输电塔结构的极限承载能力和失效模式进行了分析,进而对比上述三种超高压输电塔模型的差异。算例分析表明鼓型输电塔的空间刚架模型和空间梁桁组合模型都能反映出铁塔结构的延性破坏性质,而梁桁组合模型的极限承载力计算结果偏于安全。提出了高压输电塔的结构优化模型和超高压输电塔的塔座优化模型,并通过Python调用商业求解软件CPLEX对模型进行了求解。其中,高压输电塔的结构优化模型以结构总重量最小为目标,计及了杆单元轴心受力的强度约束、杆单元轴心受压的稳定约束,以10杆桁架结构为算例分析对象,有效验证了模型的有效性;高压输电塔的支座优化模型以输电塔腿的总重量最小为目标,计及了应力约束、稳定约束、杆件单元细长比约束、节点位移约束和角度约束等,以酒杯型直线塔为算例分析对象,有效验证了模型的有效性。

关键词：高压输电塔有限元模型动力特性分析极限承载力失效模式结构优化支座优化

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Rheological and Morphological Characterization of Modified Bitumen with Cup Lump Rubber

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Journal of Renewable Materials 2023年第5期11卷 2433-2451页

作者： Mohammed Albuaymi suleiman Abdulrahman Fayez alanazi hani alanazi Musa Adamu Department of Civil and Environmental Engineering College of EngineeringMajmaah UniversityAl-Majmaah11952Saudi Arabia Department of Civil Engineering Kebbi State University of Science and TechnologyAlieroKebbiNigeria school of Civil Engineering Universiti Teknologi MalaysiaJohor Bahru81310Malaysia Department of Civil Engineering College of EngineeringJouf UniversitySakaka72388Saudi Arabia Engineering Management Department College of EngineeringPrince Sultan UniversityRiyadh11586Saudi Arabia Department of Civil Engineering Bayero UniversityKanoPMB 3011Nigeria

Pure bitumen is not suitable for heavy traffic loads;hence modifiers are used to improve the bitumen ***,cup lump rubber(CLR)has become a preferred modifier due to its outstanding performance and less ***,little is known about the interactions between CLR and ***,this study investigates the behavior of bitumen with *** percentages of CLR(2.5%,5.0%,7.5%,and 10.0%by weight of bitumen)were used to modify conventional 60/70 penetration grade *** modified bitumen was evaluated through different laboratory testing such as dynamic shear rheometer,rotational viscosity,softening point,bending beam rheometer,ductility,and elastic *** testing results show that the addition of CLR increased the bitumen’s rutting resistance by 3 PG grades at high *** low pavement temperatures,the cup lump rubber modified bitumen(CMB)can withstand up to−34℃.Fourier Transform Infrared(FTIR)analysis shows that the Aromaticity index at 1600 cm^(−1) rose as the CLR percentage increased,indicating the formation of a binder with a compact *** is expected to improve the elasticity of bitumen throughπ-π*** Force Microscopy(AFM)results showed the Catana phase increased in size and quantity at 5.0%and 7.5%CLR *** contact angle measurement revealed that the binders are hydrophobic and tend to repel the dropped water on the bitumen surface.

关键词： Cup lump rubber polymer modified bitumen hydrophobicity natural rubber

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Irritable Bowel syndrome among Medical and Non-Medical Northern Border University students, Kingdom of saudi Arabia: Across sectional study

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Open Journal of Gastroenterology 2016年第6期6卷 188-195页

作者： Nagah Mohamed Abo El-Fetoh Mohamed Mousa Abd El-Mawgod Nesreen A. Mohammed Hanan saleh A. Alruwaili Entsar owaid M. alanazi Public Health and Community Medicine Department Faculty of Medicine Sohag University Sohag Egypt Northern border University Arar KSA Public Health and Community Medicine Department Faculty of Medicine Al-Azhar University Assiut Egypt Public Health Faculty of Medicine Sohag University Sohag Egypt

Background: Irritable Bowel syndrome (IBs) is a common functional gastrointestinal disorder (FGID), characterized by abdominal pain or discomfort and alteration in bowel habits. Aim of the study: To determine the overall prevalence, prevalence of each type and risk factors of IBs among Northern Border University (NBU) students, Arar, Kingdom of saudi Arabia. Material and methods: We use cross sectional, descriptive study with multistage cluster probability sample. Using Rome III criteria questionnaire of IBs;which is a self-administrated consists of ten questions assessing the current status of an apparently normal person. The questionnaire is administrated to Northern Border University students. Results: A total of 228 University students of them, 94 (41.2%) males and 134 (58.8%) females were included in the study. The overall prevalence of IBs according to Rome III criteria in northern border University was (32.5%). The disease prevalence was 33.6% in females and 30.9% in males. Among the study participants, the most common type of IBs was the mixed one 12.7%, followed by the constipation predominant type 10.5%, then the diarrhea pre-dominant type 5.7% while the least common was unsubtyped cases (3.5%). statistically significant increase in prevalence of this disease was found among female students (60.8% vs. 39.2% in males) (p-value students who experienced psychic stress and irritability (79.7%) (p-value students who were obese (p-value sion: The results of this study concluded the prevalence rate of 32.5% for IBs among the students studying in Northern Border University. stress and high body mass index were significantly associated with IBs. In addition, this study concluded that IBs was not significantly associated with socio-demographic characteristics and smoking.

关键词： Prevalence Irritable Bowel syndrome IBs Rome III Criteria

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