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Experimental and analytical investigation on friction resistance force between buried coated pressurized steel pipes and soil

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 615-629页

作者： Shaurav ALAM Tanvir MANZUR john matthews Chris BARTLETT Erez ALLOUCHE Brent KEIL john KRAFT Department of Civil Engineering and Construction Engineering Technology Louisiana Tech UniversityRustonLA 71270USA Department of Civil Engineering Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh Georgia Tech Research Institute AtlantaGA 30332USA Stantec Inc. Edmonton T5J0K4Canada North West Pipe Company VancouverWA 98684USA

This paper presents an analytical approach for estimating frictional resistance to pipe movement at soil and external pipe surface of buried coated pressurized steel pipes relative to the internal thrust *** proposed analytical method was developed based on 36 experiments,which involved three coating types(cement mortar(CM),polyurethane type-I(PT-I),prefabricated plastic tape(PPT))on pipes’surfaces,three different soils(pea-gravel(PG),sand(S),silty-clay(SC)),and four simulated over burden depths above the pipe’s *** showed frictional resistance decreased with increasing over burden depth above the pipe’s *** degree of frictional resistance at the pipe-soil interface was found to be in the order of PG>SC>S for all coating variations and overburden *** coated pipe buried in all three types of soil produced significantly higher frictional resistance as compared to other coating *** on experimental data,the developed analytical introduced a dimensionless factor“Z”,which included effects of types of coatings,soil,and overburden depths for simplified rapid *** showed that the method provided a better prediction of frictional resistance forces,in comparison to previous analytical methods,which were barely close in predicting friction resistance for different coating variations,soil types,and overburden *** resistance force values reported herein could be considered conservative.

关键词： friction resistance force thrust force coated pressurized steel pipe soil type overburden depth

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国外天然气管道检测技术现状及启示

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天然气工业 2018年第2期38卷 103-111页

作者：卢泓方吴晓南 Tom Iseley john matthews 彭善碧西南石油大学石油与天然气工程学院美国路易斯安那理工大学非开挖技术中心西南石油大学土木工程与建筑学院

中国天然气管道即将进入事故高发的老龄化阶段,如何高效进行管道检测成为亟待解决的问题。为此,在调研大量论文、研究报告和企业信息的基础上,围绕天然气管道可视化检测、管壁金属损失检测、泄漏检测和在线监测技术,对国外已成熟应用而... 详细信息

中国天然气管道即将进入事故高发的老龄化阶段,如何高效进行管道检测成为亟待解决的问题。为此,在调研大量论文、研究报告和企业信息的基础上,围绕天然气管道可视化检测、管壁金属损失检测、泄漏检测和在线监测技术,对国外已成熟应用而国内正处于起步阶段的天然气管道检测技术进行了全面介绍,分析了该技术在我国应用所面临的主要障碍,并从检测功能、技术适应性、技术改进等方面总结了检测技术的发展方向。结论认为:(1)国外天然气管道检测技术主要针对腐蚀坑、缺陷、剩余壁厚和泄漏,很多技术都以管道机器人为载体,配合其他技术理论及多种传感器行使技术功能,管道检测的技术和设备必将朝着综合检测(检测多种数据)的方向发展;(2)国外天然气管道的部分检测技术仅可应用于小口径管道,对于大口径管道则具有一定的局限性,提高检测设备的适应性是必然趋势;(3)国外天然气管道检测技术在我国应用的难点主要体现在目前国内尚未形成检测技术实施和验收的标准体系,很多检测数据需要人为解释且暂时缺乏相关的专业培训;(4)自动解读数据成为管道检测的一个新兴发展方向,届时机器可自动识别管道内缺陷、腐蚀状况等参数并提供可靠性较高的检测报告;(5)提高检测设备的续航能力、数据存储能力和远传能力是检测技术改进的发展方向;(6)管道检测技术配套完整性管理平台的研发,能够促进天然气管道的智能化管理。

关键词：天然气管道状态评价国外检测技术可视化检测金属损失泄漏在线监测中国

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国外天然气管道非开挖安装、修复及更换技术

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天然气工业 2018年第3期38卷 110-120页

目前,我国天然气管道行业主要面临多数老龄期天然气管道需要修复或更换、天然气管道的建设速度与天然气需求量的增速高度不匹配等问题,如何高效安装、修复和更换天然气管道便成为我国大力推动天然气市场发展需要解决的重点问题。为此,... 详细信息

目前,我国天然气管道行业主要面临多数老龄期天然气管道需要修复或更换、天然气管道的建设速度与天然气需求量的增速高度不匹配等问题,如何高效安装、修复和更换天然气管道便成为我国大力推动天然气市场发展需要解决的重点问题。为此,在分析我国天然气管道非开挖安装、修复和更换技术需求的基础上,围绕天然气管道非开挖安装、修复及更换技术,对国外已成熟应用的技术进行了全面介绍,并分析了非开挖系列技术的发展方向。结论认为:(1)天然气管道非开挖安装技术正处于不断改进的阶段,并正在朝着"能够适用于各种类型的土壤、能够铺设更大管径的管道、能够以更快的速度施工"的方向发展;(2)我国目前非开挖修复和更换技术所面临的问题主要体现在缺乏评价管道修复或更换的质量标准、缺乏具有非开挖修复和更换技术经验的设计和施工人员;(3)国外非开挖修复技术已能够适用于城镇燃气中低压管道,但对于高压管道其应用还存在着一定的局限性,因此提高内衬材料强度是解决该问题的关键;(4)天然气管道非开挖检测、安装、修复(或更换)技术需要形成完整的体系,才能更有利于提高管道完整性管理的水平。

关键词：天然气管道国外非开挖技术安装修复更换发展方向管道完整性管理中国

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Challenges and Opportunities in Preserving Key Structural Features of 3D-Printed Metal/Covalent Organic Framework

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Nano-Micro Letters 2024年第8期16卷 362-381页

作者： Ximeng Liu Dan Zhao john Wang Department of Materials Science and Engineering National University of SingaporeSingapore 117574Singapore Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117585Singapore National University of Singapore(Chongqing)Research Institute Chongqing 401123People’s Republic of China

Metal-organic framework(MOF)and covalent organic framework(COF)are a huge group of advanced porous materials exhibiting attractive and tunable microstructural features,such as large surface area,tunable pore size,and functional surfaces,which have significant values in various application *** emerging 3D printing technology further provides MOF and COFs(M/COFs)with higher designability of their macrostructure and demonstrates large achievements in their performance by shaping them into advanced 3D ***,the currently available 3D printing M/COFs strategy faces a major challenge of severe destruction of M/COFs’microstructural features,both during and after 3D *** is envisioned that preserving the microstructure of M/COFs in the 3D-printed monolith will bring a great improvement to the related *** this overview,the 3D-printed M/COFs are categorized into M/COF-mixed monoliths and M/COF-covered *** differences in the properties,applications,and current research states are *** up-to-date advancements in paste/scaffold composition and printing/covering methods to preserve the superior M/COF microstructure during 3D printing are further discussed for the two types of 3D-printed M/*** the analysis of the current states of 3D-printed M/COFs,the expected future research direction to achieve a highly preserved microstructure in the 3D monolith is proposed.

关键词： Metal-organic frameworks Covalent organic frameworks 3D printing Microstructure Monolith

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滑坡对埋地天然气管道的作用机理分析

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中国地质灾害与防治学报 2019年第6期30卷 59-67页

作者：彭善碧廖文徐明军 TomIseley johnmatthews 西南石油大学土木工程与建筑学院四川成都610500 塔里木油田克拉油气开发部新疆塔里木841000 美国路易斯安那理工大学非开挖技术中心美国路易斯安娜州71270

滑坡是危害天然气管道安全的地质灾害之一,在研究滑坡对埋地天然气管的作用机理以来,各种分析方法和模型都有着不同的优点与缺陷,在调研、分析大量论文、研究报告的基础上,笔者以滑坡区埋地天然气管道为对象,总结了管土作用研究方法并... 详细信息

滑坡是危害天然气管道安全的地质灾害之一,在研究滑坡对埋地天然气管的作用机理以来,各种分析方法和模型都有着不同的优点与缺陷,在调研、分析大量论文、研究报告的基础上,笔者以滑坡区埋地天然气管道为对象,总结了管土作用研究方法并进行了模型对比,并发现在现有的土体对埋地天然气管道的作用研究中主要考虑水平、轴向和竖向三个方向的作用,未考虑三者的相互影响。另外提出随着聚乙烯塑料管(PE管)在城市燃气输配管网中的广泛应用,未来对非线性管材在滑坡作用下的力学响应及全尺寸模型试验等方面还需进一步研究。

关键词：滑坡天然气管道管土作用

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A Population Dynamics Approach to the Distribution of Space Debris in Low Earth Orbit

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Communications on Applied Mathematics and Computation 2024年第1期6卷 340-353页

作者： john Jurkiewicz Peter Hinow Department of Mathematical Sciences University of Wisconsin-MilwaukeeMilwaukeeWI53201USA

The presence of the debris in the Earth’s orbit poses a significant risk to human activity in outer *** debris population continues to grow due to ground launches,the loss of external parts from space ships,and uncontrollable collisions between objects.A computationally feasible continuum model for the growth of the debris population and its spatial distribution is therefore *** we propose a diffusion-collision model for the evolution of the debris density in the low-Earth orbit and its dependence on the ground-launch *** parametrize this model and test it against data from publicly available object catalogs to examine timescales for the uncontrolled ***,we consider sensible launch policies and cleanup strategies and how they reduce the future risk of collisions with active satellites or space ships.

关键词： Population dynamics Space debris Kessler syndrome Diffusion Low-Earth orbit

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Erosion response to anthropogenic activity and climatic changes during the Holocene: case studies in northwestern China and southern Norway

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Journal of Geographical Sciences 2002年第4期12卷 467-471页

作者： HE Xiubin1,2, TANG Keli1, john A matthews3, Geraint Owen3(1. Institute of Soil and Water Conservation, CAS, Yangling 712100, China 2. Northwest SCI-Tech University of Agriculture and Forestry, Yangling 712100, China 3. Department of Geography, Univer Institute of Soil and Water Conservation CAS Yangling China Northwest SCI-Tech University of Agriculture and Forestry Yangling China Department of Geography University of Wales Swansea UK

Soil erosion assessment and prediction play critical roles in addressing problems associated with erosion control or soil conservation. The past dynamics of soil erosion can provide valuable information for us to understand the relations of soil erosion to environmental change and anthropogenic activity. The present paper has compared Holocene climatic changes in northwestern China with those in southern Norway, and investigated the past dynamics of erosion activity during the Holocene. Modern soil erosion on the Loess Plateau is a combination of the intensive natural erosion and human-induced erosion, the latter being four times greater than the former. Because of global warming and increasing human activities, climate on the Loess Plateau is becoming dryer and more unstable, causing an enhanced erosion problem and water scarcity. In the arctic-alpine region of southern Norway, however, the global warming and regional wetting caused expansion of the largest European ice cap. This has accentuated the erosion in that region, with a higher frequency of avalanches and debris flows.

关键词： anthropogenic activity China climate changes erosion response Norway

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Surgical treatment of inflammatory bowel disease:From the gastroenterologist’s stand-point

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World Journal of Gastrointestinal Surgery 2024年第5期16卷 1235-1254页

作者： john K Triantafillidis Inflammatory Bowel Disease Unit “Metropolitan General”HospitalHolargos 15562AtticaGreece Hellenic Society of Gastrointestinal Oncology Haidari 12461AthensGreece

Treatment of ulcerative colitis(UC)and Crohn’s disease(CD)represents,in the majority of cases,a real challenge to the gastroenterologist’s abilities and skills as well as a clinical test concerning his/her levels of medical knowledge and *** the last two decades,our pharmaceutical arsenal was significantly strengthened,especially after the introduction of the so-called biological agents,drugs which to a large extent not only improved the results of conservative treatment but also changed the natural history of the ***,colectomy is still necessary for some patients with severe UC although smaller compared to the past,precisely because of the improvements achieved in the available conservative ***,surgeries to treat colon dysplasia and cancer are increasing to some *** the same time,satisfactory improvements in surgical techniques,the pre-and post-operative care of patients,as well as the selection of the appropriate time for performing the surgery have been *** patients with CD,the improvement of conservative treatment did not significantly change the need for surgical treatment since two-thirds of patients need to undergo surgery at some point in the course of their *** the other hand,the outcome of the operation has improved through good preoperative care as well as the wide application of more conservative surgical techniques aimed at keeping as much of the bowel in situ as *** article discusses the indications for surgical management of UC patients from the gastroenterologist’s point of view,the results of the emerging new techniques such as transanal surgery and robotics,as well as alternative operations to the classic ileo-anal-pouch *** author also discusses the basic principles of surgical management of patients with CD based on the results of the relevant *** self-evident is emphasized,that is,to achieve an excellent therapeutic result in patients with se

关键词： Inflammatory bowel disease Ulcerative colitis Crohn’s disease Surgery Treatment Ileo-anal-pouch anastomosis Indications Techniques

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Study of hybrid nanofluid flow in a stationary cone-disk system with temperature-dependent fluid properties

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 677-694页

作者： A.S.john B.MAHANTHESH G.LORENZINI Center for Mathematical Needs Department of MathematicsCHRIST(Deemed to be University)Karnataka 560029India School of Mathematical and Statistical Sciences The University of Texas Rio Grande ValleyTexas 78539U.S.A. Department of Engineering and Architecture University of ParmaParma 43124Italy

Cone-disk systems find frequent use such as conical diffusers,medical devices,various rheometric,and viscosimetry *** this study,we investigate the three-dimensional flow of a water-based Ag-Mg O hybrid nanofluid in a static cone-disk system while considering temperature-dependent fluid *** the variable fluid properties affect the dynamics and heat transfer features is studied by Reynolds's linearized model for variable viscosity and Chiam's model for variable thermal *** single-phase nanofluid model is utilized to describe convective heat transfer in hybrid nanofluids,incorporating the experimental *** model is developed as a coupled system of convective-diffusion equations,encompassing the conservation of momentum and the conservation of thermal energy,in conjunction with an incompressibility condition.A self-similar model is developed by the Lie-group scaling transformations,and the subsequent self-similar equations are then solved *** influence of variable fluid parameters on both swirling and non-swirling flow cases is ***,the Nusselt number for the disk surface is *** is found that an increase in the temperature-dependent viscosity parameter enhances heat transfer characteristics in the static cone-disk system,while the thermal conductivity parameter has the opposite effect.

关键词： hybrid nanofluid cone-disk system laminar flow variable fluid property Nusselt number

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Does photobiomodulation require glucose to work effectively?

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Neural Regeneration Research 2024年第5期19卷 945-946页

作者： Jaimie Hoh Kam john Mitrofanis UniversitéGrenoble Alpes Fonds de Dotation ClinatecGrenobleFrance University College London Institute of OphthalmologyUK

A main requirement for cells to function normally is the availability of ***,available either direct from circulation or storage,is converted to the essential energy that cells need to drive critical intrinsic *** cells are deprived of glucose,they become dysfunctional and suffer ***,the use of specific wavelengths of light on body tissues,has been shown to promote,through small organelles called mitochondria,the metabolism of glucose to make energy for cells;this energy can be used to improve cell function and *** this perspective,we hypothesize that the availability of glucose is central to the core mechanism of photobiomodulation;that photobiomodulation is at its most efficient in stimulating mitochondrial activity and improving cell function when there is glucose readily available.

关键词： metabolism distress stimulating

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