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粉喷桩复合地基大刚度垫层特性研究及应用

粉喷桩复合地基大刚度垫层特性研究及应用

作者： Bashir abdi khalif 中南大学

学位级别：硕士

目前粉喷桩桩复合地基技术已经广泛应用于软土、粉土、淤泥质土等各类地基土的处理加固工程,取得了良好的社会经济效益。众多学者和工程技术人员也对粉喷桩复合地基进行了详细的研究,理论也趋于完善。但对垫层的研究相对较少,主要是因... 详细信息

目前粉喷桩桩复合地基技术已经广泛应用于软土、粉土、淤泥质土等各类地基土的处理加固工程,取得了良好的社会经济效益。众多学者和工程技术人员也对粉喷桩复合地基进行了详细的研究,理论也趋于完善。但对垫层的研究相对较少,主要是因为其破坏机理复杂,工作状态难以模拟。垫层是复合地基的重要组成部分,可以调整桩土的荷载分担比例,保证复合地基在荷载作用下桩与土始终共同发挥承载力。在粉喷桩复合地基中,若垫层刚度过大,垫层就成为基础的一部分,若垫层刚度过小,垫层就成为桩间土体的一部分,这两种情况都不利于垫层效应的发挥。为了充分发挥桩土复合地基的承载性能,改善桩体的荷载承担比,国内外学者进行了大量的理论与试验研究,研究发现在基础下设置适当厚度的有散体材料组成的垫层,可以调整复合地基中桩与土的荷载分配,优化并提高复合地基的承载性能。这是因为在荷载作用下,桩体相对于桩间土因具有较大的刚度会对垫层产生向上的刺入,从而产生复合地基中的刺入变形。同时,垫层中的散体材料会因桩顶的刺入向桩间土产生滑动,以补充桩间土较大的压缩变形。整个受力过程中,桩体与桩间土体始终通过垫层的调节共同承担上部基础荷载,即桩间土体的承载力得到了发挥。因此,对于桩体为粘结材料的复合地基,垫层的设置对其承载机理有着很大的影响。粉喷桩复合地基技术是利用机械进行深部搅拌的一种地基加固处理技术,是利用专门机械通过高压气流将粉体加固材料喷射入被加固的软弱土层中,同时机械叶片旋转使其与原位土体充分混合。这样,软弱土体会与粉料发生水化、固结等一系列化学反应,在短期内凝结形成具有较强整体性、水稳定性和承载能力的柱状体。在荷载作用下与地基土共同形成复合地基,降低原位软弱土体的沉降。粉喷桩加固软土地基,还有很多的独特的好处:由于粉喷桩施工时直接将粉体固化材料和软弱地基土拌合,因此充分利用了原位土体;并且在粉喷桩施工时,地基土不会发生侧向挤出,因此对周围土体及建筑物扰动很小;水泥土的配合比可以根据设计要求和地基土的属性灵活设计;与混凝土桩相比,节省了大量的建材,降低了成本;粉喷桩的布置形式可以根据上部结构灵活设置。粉喷桩的施工方法属于深层搅拌法,主要适用于加固工程性质较差的粉土以及含水量大且承载力较低的粘性土体。对于没有工程经验的地区或者泥炭土、有机土以及粘土塑性指数大于25时,需要进行现场试验来指导设计。通过水泥加固土的室内试验发现,当土中的粘土矿物如蒙脱石、多水高岭石等含量较高时,粉喷桩的加固效果较好;而土中含有较多的多水氯石英、伊利石以及氯化物的时,或者好友较多的有机质、PH值较低、有地下水硫酸盐的侵蚀时,加固效果较差。粉喷桩复合地基的沉降与基础刚度、桩长、垫层厚度和刚度、下卧层土、桩侧土特性、桩土置换率等因素都有较大的关系。模拟试验和数值分析均表明:刚性基础下,由于受到刚性基础的约束作用,桩与桩间土的沉降协调一致,桩承受较大的荷载,桩土荷载分担比较大,且随着沉降发展逐步增加;而柔性基础下由于不受约束,桩与土的沉降并不同步,桩体产生沉降的同时还会向上刺入柔性基础,此时,土体相对刚性基础承担较大的载荷。相对于刚性基础来说,柔性基础下的复合地基会产生较大的沉降,且极限承载力也较小。同一基础荷载作用下,桩长不同,桩、土荷载分担比不同,从而桩间土的压缩变形也不同。临界桩长范围内,桩的长度与桩间土的压缩变形呈反比。不同厚度和刚度的垫层也会对粉喷桩复合地基的沉降产生影响,垫层刚度相同时,厚度越小,桩承担的荷载越多,桩体向上刺入量也就越小。对于粉喷桩,由于桩身强度并不高,当垫层刚度较大时,桩顶几乎没有向垫层的刺入。下卧层土的性质越好,桩向下刺入就越困难,桩侧土性质越好,桩长范围内的土的压缩量也越大,进而基础总沉降量越大。为了最大程度发挥粉喷桩复合地基的承载特性,实际工程应用时常常在基础下设置垫层,以改善粉喷桩复合地基中的桩土荷载分配。并且很多学者对垫层的效应进行了深入的研究。研究表明,垫层作为上部荷载向下部复合地基传递过程中的过渡,其厚度和模量的变化都会对粉喷桩复合地基荷载传递过程有着显著的影响。设置垫层后,粉喷桩桩体的最大应力点下移到某一深度,且会随着垫层厚度的增加继续下移。垫层厚度在一定范围内也影响桩土应力比的变化,可以达到优化桩、土荷载分配的效果。数值试验结果亦表明,垫层对复合地基的影响均发生在浅层范围内,并随着桩体刚度的增大变得明显。路堤荷载下的粉喷桩复合地基中,随着垫层刚度的增加,桩土应力比增大,当垫层刚度大到一定值时,桩土应力比趋于稳定,近似于桩基础。由于垫层的设置,桩与土因模量差异而产生不均匀沉降,并且得到垫层的补偿,这样一来,会在桩侧产生一定深度的负摩阻区,致使桩身的最大应力区往往发生在桩身某个部位,而不是桩顶。若垫层刚度较小,则会产生桩体刺入路堤对路堤造成破坏,并且如此一来导致桩间土应力过大,提早破坏

关键词：喷桩复合地基垫层工作机理试验数值模拟

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砂砾岩油藏注CO2开采数值模拟研究

砂砾岩油藏注CO2开采数值模拟研究

作者： Abdourahman Mahamoud abdi 中国石油大学(华东)

学位级别：硕士

砂砾岩储层具有高度非均质性,岩性在以快速相变为特征的深部和复杂的孔隙结构之间变化如此之快,导致驱油效率低下。CO2注入是开发这类高采收率油藏的良好选择。应选择CO注入方法并评估CO封存潜力。在目标区数据收集的基础上,构建了用于... 详细信息

砂砾岩储层具有高度非均质性,岩性在以快速相变为特征的深部和复杂的孔隙结构之间变化如此之快,导致驱油效率低下。CO2注入是开发这类高采收率油藏的良好选择。应选择CO注入方法并评估CO封存潜力。在目标区数据收集的基础上,构建了用于模拟的概念性油藏模型类型。使用计算优化工具PVT Winprop,收集了一系列实验数据来构建和分析流体模型数据的行为。使用CMG的模拟器GEM(广义状态方程模型组合油藏模拟器)通过流体模型的表征来执行CO-EOR的优化性能,通过考虑许多因素来分析CO驱和WAG过程的混相过程参数注入周期、注入速率和产量、WAG比和段塞大小,以评估不同的注入策略和注入时间,以优化石油采收率和CO储存能力。随着储层压力降低或接近最小混相压力(MMP),窜流和指压效应变得有利。结果表明,注入CO可以提高砂砾岩油藏的采收率。由于CO驱油过程中的油藏压力略低于最低混相压力,CO2可以溶解到油中,降低油的粘度。但在WAG过程中,储层压力略低于MMP,因此与CO注入过程中发生的窜流和指流一样多。与CO驱油方法和恒定WAG比相比,在WAG注入中,CO2注入使采收率提高了70%,WAG比可变。此外,CO也可以储存在水库中。

关键词：砂砾岩油藏 CO2驱气水交替驱 CO2埋存数值模拟

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卒中样起病的代谢性脑病3例

卒中样起病的代谢性脑病3例

作者： abdiWELI AHMED abdi 绍兴文理学院

学位级别：硕士

目的探讨与总结卒中样起病的代谢性脑病的诊断经验。方法跟踪并分析3例卒中样起病,最后明确为不同病因代谢性脑病的病例资料,对其临床检查以及诊断等资料进行获取。结果3例患者诊断为:肝性脑病、线粒体脑肌病伴高乳酸血症和脑卒中样发作... 详细信息

目的探讨与总结卒中样起病的代谢性脑病的诊断经验。方法跟踪并分析3例卒中样起病,最后明确为不同病因代谢性脑病的病例资料,对其临床检查以及诊断等资料进行获取。结果3例患者诊断为:肝性脑病、线粒体脑肌病伴高乳酸血症和脑卒中样发作(Mitochondrial encephalopathy with lactic acidosis and stroke-like episodes,MELAS)以及高钙、高甲状旁腺素引起的线粒体功能损害代谢性脑病。结论不同病因代谢性脑病的发生并非罕见,早期易被误诊,需要提高识别度。

关键词：卒中样起病代谢性脑病肝性脑病 MELAS

服务质量评估与顾客满意度研究——以埃塞俄比亚航空公司为例

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服务质量评估与顾客满意度研究——以埃塞俄比亚航空公司为例

作者： abdi Zeki Mohammed 河北地质大学

学位级别：硕士

Today competition is not only rife,but growing more intense ***,companies need to start paying keen attention to their competitors,they must understand their *** are suffering from each *** have to believe customers as core concept of their business;customer satisfaction is what guarantees the future of air lines and it is achievable by taking up their services and passengers’ *** other words,service quality is typically defined in terms of consumer *** purpose of this study is to measure the service quality and its subsequent effect on customer satisfaction at Ethiopian airlines using a model that describes various dimensions of service *** this purpose the researcher has studied the service quality of the airline using SERVQUAL *** sampling technique was used in the study to take a sample from the infinite population.A total sample of 150 respondents who have made a flight with Ethiopian airlines were taken as a respondent.A questionnaire was designed based on the model in order to examine all the five factors of service quality in the model for airline *** is inclusively concluded that passengers of EAL are not satisfied with the perceived services of three dimensions of the model and it warns the airline to focus on passengers ***,assurance,responsiveness,reliability and empathy are five features of the model and in tangibles and reliability the passengers are satisfied,but in the remaining three passengers feel *** should train employees,improve visually attractive facilities and coordinate all people,departments and organizations involved with the ***,managers at EAL should measure passengers’ satisfaction and service quality seasonally to keep the services corresponded with customers’ opinions.

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Handling and Hygienic Production Practices of Goat Milk in Degahbur District of Jarar Zone, Somali Regional State, Ethiopia

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Open Journal of Animal Sciences 2022年第3期12卷 524-536页

作者： abdi Ahmed Tadele Amentie Kawnin abdimahad Mohamud Mohamed Department of Animal and Range Sciences College of Dry Land Agriculture Jigjiga University Jigjiga Ethiopia

A cross-sectional study was carried out to assess handling and hygienic production practices of goat milk in Degahbur district of Jarar zone, Somali Regional State, Ethiopia. A total of 120 households were purposively selected for this study using a stratified sampling technique. The data were collected through the questionnaire, field observations, key informants interview and focus group discussions. The study showed that majority of the sampled households were illiterate. The goats were kept in an open kraal made of thorny acacia trees on an earthen floor that had no roof. The goats were milked inside these open kraals, and were sometimes contaminated with muck and animal dung mainly the rainy season which could raise the possibility of milk contamination & spoilage. Moreover, traditional hand milking was the only milking method and majority of the respondents didn’t wash their hands and the udder of the animal before milking, indicating low community awareness and knowledge of sanitary milk production procedures. Plastic equipment which is difficult to clean and can increase milk contamination and spoilage was used. About 43.3% of the pastoralists and 76.67% of the agro-pastoralists were cleaning milk vessels regularly. The most often used plant species for smoking milk handling equipment in the study area to extend shelf life and add flavor & aroma were Acacia ethaica, Blanites galabra, and Solanum Carense. The main constraints to hygienic goat milk in the area were identified to be poor barn hygiene, poor production procedures, disease, source of washing water and lack of extension services. In general, it can be concluded that handling and hygienic production practices of goat milk used in the study area were unsanitary, which may have been primarily caused by the community’s lack of awareness & understanding as well as a lack of supporting infrastructures. Therefore, the concerned bodies should place a high priority on the improvement of hygienic practices b

关键词： Goat Milk Handling Hygienic Production

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页岩气藏数值模拟及参数优化

页岩气藏数值模拟及参数优化

作者： Ibrahim abdi Ibrahim 中国石油大学(华东)

学位级别：硕士

Unconventional gas reserves are mainly described by having low permeability which makes these reserves very challenging both technically and commercially to exploit than conventional *** gas production is intensifying globally and a lot of the activity is taking place in the United States and Canada,while others countries recently started to intensify the *** of the biggest and important deposits is Marcellus *** drilling and hydraulic fracturing technology gave the technical feasibility of production but there is a fear existing concerning the economics of shale gas *** of the worries related to limited production and economic data for shale gas *** gas is low permeable and porous formations which are both source rock and *** formations can be said to have very extreme low matrix ***’s required to carefully examine the *** drilling with multiple hydraulic fracturing along the horizontal well offers successful depletes *** modeling unconventional resources it’s necessary to effectively and efficiently model *** focus of this thesis is mainly in two *** first part is the analytical model of finite hydraulic fracture *** solution procedure is based on the analytical model developed for fractured horizontal *** addition,commercial reservoir simulator（CMG）is used to check and compare the result which is obtained from the analytical *** parameters which affect the productivity of the multiple fractured horizontal wells are studied by using trilinear *** study shows that productivity of shale reservoirs can increase when the matrix permeability and hydraulic fracture are *** thesis analysis and compares the sensitivity analysis of the two different models,trilinear model and the commercial reservoir simulator model（CMG）.The parameters which were studied include hydraulic fracture half length,hydraulic fracturing spaci

关键词：页岩气藏数值模拟参数优化

电子记录管理调查——吉布提国家社会保障基金（NSSF）的案例研究

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电子记录管理调查——吉布提国家社会保障基金（NSSF）的案例研究

作者： Nimaleh abdi Kabel 江苏大学

学位级别：硕士

记录管理在最近几十年中一直是受到学界广泛研究的主题。世界各地的组织都在努力地保持着其对记录管理研究近况的追踪。使用有效技术改善吉布提国家社会保障基金档案的相关实践举措具有重大意义,上述工作中发现的档案管理问题是推动本... 详细信息

记录管理在最近几十年中一直是受到学界广泛研究的主题。世界各地的组织都在努力地保持着其对记录管理研究近况的追踪。使用有效技术改善吉布提国家社会保障基金档案的相关实践举措具有重大意义,上述工作中发现的档案管理问题是推动本研究开展的重要因素。为了实现主要研究目标,本文提出了五项研究问题以阐明吉布提国家社会保障基金档案面临的挑战,并供给了适配的优化建议。本研究主题在吉布提尚属首次开展,有助于提升该领域的专业理论知识水平,且由于本文是针对吉布提的基准分析,因此可为其他前瞻性研究提供参考。本文主要使用定量研究手段,检测信息通信技术(ICT)对吉布提国家社会保障基金(NSSF)服务管理绩效(SMP)的影响。检验了采用电子记录管理(ERMA)的潜在中介效应作用。本研究使用SPSS软件进行了相关分析、多元回归分析和方差分析,以了解研究变量之间的关系。此外,使用结构方程模型的偏最小二乘法验证了ICT对ERMA、SMP的影响,以及ERMA对SMP的影响。研究发现,ICT的采用对ERMA和SMP产生了显著正向的影响(p<0.05),ERMA也对SMP产生了正向影响。考虑到ERMA对ICT与SMP间关系的中介作用,本文还测量了ICT对SMP的间接影响。研究结果表明,ICT对SMP的间接影响大于其直接影响,因此可以确定ERMA的中介作用。研究结果显示,增加对ICT投资和采用的管理部门决策,将对提升NSSF中ERM系统的应用水平具有基础性的意义。此外,在已经采用ICT的领域中,通过使用ERM系统也可以进一步增强SMP。

关键词：电子记录管理服务绩效信息通信技术技术接受度技术采用组织绩效

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超强力胶眼部损伤的研究进展

国际眼科杂志 2020年第9期20卷 1482-1486页

作者： Ali Torkashvand Arzhang Gordiz Fatemeh abdi Mohammad Soleimani 德黑兰医科大学Farabi眼科医院眼科研究中心伊朗德黑兰*** 伊朗医科大学 RassoulAkram医院眼科研究中心伊朗德黑兰***

该研究旨在对超强力胶可能对眼部造成的损伤问题进行回顾。本文对以往有关强力胶有害影响的文献进行了系统的研究。在过去的30年中,超强力胶对眼部的损伤问题是很常见的,其中大多数是意外事件,虽然它对眼部组织具有毒性,但通过安全教育... 详细信息

该研究旨在对超强力胶可能对眼部造成的损伤问题进行回顾。本文对以往有关强力胶有害影响的文献进行了系统的研究。在过去的30年中,超强力胶对眼部的损伤问题是很常见的,其中大多数是意外事件,虽然它对眼部组织具有毒性,但通过安全教育可以进行预防。本文阐述了眼部超强力胶损伤的处理方法,指出了预防眼部超强力胶损伤的重要性。

关键词：眼外伤胶水超强力胶水眼部损伤

Synergistic activity of lawsone methyl ether in combination with some antibiotics and artocarpin against methicillin-resistant Staphylococcus aureus, Candida albicans, and Trychophyton rubrum

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Chinese Herbal Medicines 2019年第3期11卷 321-325页

作者： Pharkphoom Panichayupakaranant abdi Wira Septama Akarawat Sinviratpong Department of Pharmacognosy and Pharmaceutical Botany Faculty of Pharmaceutical SciencesPrince of Songkla UniversityHat-YaiSongkhla 90112Thailand Phytomedicine and Pharmaceutical Biotechnology Excellence Center Faculty of Pharmaceutical SciencesPrince of Songkla UniversityHat-YaiSongkhla 90112Thailand Research Center for Chemistry Indonesian Institute of SciencesKawasan PUSPIPTEK SerpongTangerang SelatanBanten 15314Indonesia

Objective: One appealing strategy to overcome and prevent resistant problem is the use of combined two or more antibacterial substances. Lawsone methyl ether(LME) is the naphthoquinone found in the leaves of Impatiens balsamina. The objective of this study is to determine the interaction of LME with some antibiotics(ampicillin, tetracycline, norfloxacin, and clotrimazole) and a natural compound, artocarpin against methicillin-resistant Staphylococcus aureus(MRSA), Candida albicans, and Trychophyton ***: A broth microdilution method was used to determine the minimum inhibition concentration(MIC). Synergistic effects were evaluated at their own MIC using the checkerboard method and time-kill ***: LME showed moderate antibacterial activity against MRSA with MIC value of 15.6 μg/mL, and exhibited strong antifungal activities against T. rubrum and C. albicans with MIC values of 7.8 and 3.9 μg/m L,respectively. The interaction of LME with the natural compound artocarpin against MRSA produced a synergy with fractional inhibitory concentration index(FICI) value of 0.31, while the combination of LME and clotrimazole exhibited synergy against C. albicans and T. rubrum with FICI values of 0.38 and 0.24, respectively. The time-kill assays confirmed that the compounds in combination enhanced their antimicrobial activities against the resistant microorganisms with different ***: LME in combination with clotrimazole exhibited synergy effect against C. albicans and ***. In combination with artocarpin, it showed synergy effect against MRSA.

关键词： artocarpin Candida albicans clotrimazole lawsone methyl ether Staphylococcus aureus synergy Trychophyton rubrum