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Chinese Journal of Polymer Science 2023年第6期41卷 942-955,I0010页

作者： Bu-Yong Wu Yu-Dong Cai Xiao-Wen Zhao Lin Ye State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu 610065China School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Synthetic Resin Laboratory Petrochemical Research InstitutePetro ChinaBejing 102206China

Fabrication of polyethylene(PE)pipe with significantly enhanced hoop strength and burst pressure is essential necessary for high transportation *** this work,biaxially oriented PE/ultrahigh molecular weight polyethylene(PE/UHMWPE)blend pipes were fabricated on self-made pipe solid-phase die drawing *** to formation of chain entanglement network and enhanced viscoelasticity,incorporation of UHMWPE chains improved stretchability and biaxial orientation degree of blend *** die drawing,formation of more miscible blend system make long UHMWPE chains be sufficiently stretched under load,and such extended-chain conformation of UHMWPE acted as shish structure and induced short PE chains to array orderly and form kebab *** increasing axial draw ratio,the lamellae remarkably deviated from hoop to axial direction,while the blend pipe exhibited higher crystallinity and orientation degree than that of PE pipe,presenting a more uniform and dense biaxial orientation structure with shish-kebab *** a result,the blend pipe showed roughly 99%increase in tensile strength along hoop direction and 25%increase in burst pressure,*** biaxial self-reinforced PE/UHMWPE blend pipes exhibit promising application prospect as high-pressure transportation pipelines in civil engineering.

关键词： axial chains pipes

Investigating the influence of delamination on the stiffness of composite pipes under compressive transverse loading using cohesive zone method

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1316-1323页

作者： Sattar MALEKI Roham RAFIEE Abolfazl HASANNIA Mohammad Reza HABIBAGAHI Department of Mechanical Engineering Faculty of EngineeringQuchan University of TechnologyQuchan 94771-67335Iran Composites Research Laboratory Faculty of New Sciences and TechnologiesUniversity of TehranTehran ***Iran

The effect of delamination on the stiffness reduction of composite pipes is studied in this *** stiffness test of filament wound composite pipes is simulated using cohesive zone *** modeling is accomplished to study the effect of the geometrical parameters including delamination size and its position with respect to loading direction on stiffness of the composite *** first,finite element results for stiffness test of a perfect pipe without delamination are validated with the experimental results according to ASTM *** is seen that the finite element results agree well with experimental *** the finite element model is developed for composite pips with delaminated areas with different primary ***,the effect of the size of delaminated region on longitudinal and tangential directions and also its orientation with respect to loading direction on delamination propagation and stiffness reduction of the pipes is assessed.

关键词： delamination composite pipes stiffness test cohesive zone method

3D fracture modelling and limit state analysis of prestressed composite concrete pipes

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Frontiers of Structural and Civil Engineering 2019年第1期13卷 165-175页

作者： Pengfei HE Yang SHEN Yun GU Pangyong SHEN School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China Shanghai SMI Engineering Project Management Co. Ltd.Shanghai 201103China

In this manuscript,we study fracture of prestressed cylindrical concrete *** concrete pipes play a major role in tunneling and underground *** structure is modelled fully in 3D using three-dimensional continuum elements for the concrete structure which beam elements are employed to model the *** allows the method to capture important phenomena compared to a pure shell model of concrete.A continuous approach to fracture is chosen when concrete is subjected to compressive loading while a combined continuous-discrete fracture method is employed in *** model is validated through comparisons with experimental data.

关键词： cylindrical concrete structures limit state analysis 3D fracture modelling prestressed composite pipes reinforced concrete three-point bending test

Self-Detection of Leaking pipes by One-Dimensional Photonic Crystals

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Chinese Physics Letters 2012年第6期29卷 172-174页

作者： ZHOU Yan YIN Li-Qun Department of Physics Yanshan UniversityQinhuangdao 066004 Educational Administration Hebei Normal University of Science and TechnologyQinhuangdao 066004

We report a new self-detection control system for leaking pipes by making use of the surface defects of 1D photonic crystals,where the key concept is analog to the Bragg fiber *** current low costs and coating techniques of SiO2 are beneficial to the applications,and its error is below the standard *** problem of leaking pipes can be resolved by devising a remote pipeline control system which combines a long-distance pipeline and a signal transmission system.

关键词： fiber Crystal pipes

Sustainable dropwise condensation enabled ultraefficient heat pipes

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Droplet 2023年第1期2卷 64-72页

作者： Wei Chang Kai Luo Pengtao Wang Ahmed A.Abdulshaheed Chen Li State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchunChina Department of Thermal Engineering College of Automotive EngineeringJilin UniversityChangchunChina Department of Mechanical Engineering University of South CarolinaColumbiaSouth CarolinaUSA Oak Ridge National Laboratory Oak RidgeTennesseeUSA

Heat pipes play a critical role in determining the operations,safety,and energy efficiency of *** main focus to improve the heat pipe performance is on the evaporator design or wicking ***,the intrinsic limitation comes from the condenser,which is fundamentally constrained by inefficient filmwise condensation(FWC).In this study,we successfully achieved a peak effective thermal conductivity(keff)of~140 kW/(m·K)on widely used groove heat pipes by implementing sustianble dropwise condensation(DWC)and integrating with enhanced *** better understand the working mechanisms of the ultraefficient heat pipe,both the evaporator and condenser of the heat pipes have been modified *** results show that up to 296%enhancements on the keff can be achieved under various inclination angles by only inducing DWC in the condenser *** drawback of temperature fluctuations induced by DWC in smooth heat pipes appears to be effectively solved using the grooves‐wicking ***,by integrating the nanostructured evaporator,the keff of the heat pipe can be boosted up to 517%compared to conventional groove heat *** study,for the first time,demonstrates the huge potential of engineering both the condenser and evaporator simultaneously in developing ultraefficient heat pipes.

关键词： pipes integrating operations

Measurement of thin liquid film thickness in pipes based on optical interferometry

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Optoelectronics Letters 2022年第8期18卷 489-494页

作者： XUE Ting WU Yan School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China

Accurate measurement of the thin liquid film thickness in pipes is the foundation for studying the characteristics of the *** this paper,an interferometry-based measurement of liquid film thickness in transparent pipes is developed,which can greatly improve the accuracy,extend the lower limit of measurement and provide a new technical approach for the calibration and *** light intensity distribution is established based on the optical path analysis and a mathematical model.A new algorithm to solve the direction ambiguity is developed to reconstruct the phase ***,the effect of the pipe wall is taken into account,which can be suppressed by image subtraction and enhancement *** proposed method is of high accuracy and robustness,whose reconstruction errors are 0.064%and 0.25%for the smooth and slight fluctuating liquid films,respectively.

关键词： film. pipes interferometry

Analytic study on the optimal control of water hammer waves in pipes

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Journal of Harbin Institute of Technology(New Series) 2009年第6期16卷 756-760页

作者：曹慧哲贺志宏何钟怡谈和平 School of Municipal and Environmental Engineering Harbin Institute of Technology School of Energy Science and Engineering Harbin Institute of Technology

To realize the accurate control of water hammer in pipes by valve stroking, based on basic differential equations of water hammer subjected to initial and boundary conditions, the traveling solution of wave equations in finite region was applied to the linear water hammer problem. With the given velocity function at the valve and the introduction of curve integration independent of integral path, the exact analytic solution of dimensionless water hammer pressure was obtained in the course of valve closing. Based on the definition of eigen wave height, optimal eigen wave height and observation time, the control goal of water hammer pressure and the judgment rule of the optimal eigen wave height were determined, then the optimal velocity function in the calculated example was derived, which can reduce the water hammer pressure maximally. According to this function, a valve closing program was set, and the optimal control of water hammer could be realized.

关键词： pipes water hammer waves traveling solution optimal control extremum

Evidence relating cigarettes,cigars and pipes to cardiovascular disease and stroke:Meta-analysis of recent data from three regions

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World Journal of Meta-Analysis 2023年第6期11卷 290-312页

作者： Peter Nicholas Lee Katharine J Coombs Jan S Hamling Medical Statistics and Epidemiology P.N.Lee Statistics and Computing Ltd.Sutton SM25DASurreyUnited Kingdom

BACKGROUND More recent data are required relating to disease risk for use of various smoked products and of other products containing *** we published metaanalyses of recent results for chronic obstructive pulmonary disease and lung cancer on the relative risk(RR)of current compared to never product use for cigarettes,cigars and pipes based on evidence from North America,Europe and *** now report corresponding up-to-date evidence for acute myocardial infarction(AMI),ischaemic heart disease(IHD)and *** To estimate,using recent data,AMI,IHD and stroke RRs by region for current smoking of cigarettes,cigars and *** Publications in English from 2015 to 2020 were considered that,based on epidemiological studies in the three regions,estimated the current smoking RR of AMI,IHD or stroke for one or more of the three *** studies should involve at least 100 cases of stroke or cardiovascular disease(CVD),not be restricted to populations with specific medical conditions,and should be of cohort or nested case-control study design or randomized controlled trials.A literature search was conducted on MEDLINE,examining titles and abstracts initially,and then full *** papers were sought from reference lists of selected papers,reviews and *** each study identified,we entered the most recent available data on current smoking of each product,as well as the characteristics of the study and the RR *** RR estimates were derived using random-effects meta-analysis for stroke and,in the case of CVD,separately for IHD and *** cigarette smoking,where far more data were available,heterogeneity was studied by a wide range of *** cigar and pipe smoking,a more limited heterogeneity analysis was carried out.A more limited assessment of variation in risk by daily number of cigarettes smoked was also *** Current cigarette smoking:Ten studies gave a random-effects RR for AMI of 2.72[95%confide

关键词： Cigarettes Cigars pipes Cardiovascular disease Stroke Meta-analysis Review

The Interlayer Stress Analysis of Polyethylene-steel Composite pipes

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新型工业化 2016年第7期6卷 28-33页

作者： WEI Xu-guang Northeastern University Engineering & Research Institute Co. Ltd

Polyethylene-steel Composite pipes is widely used in conveying corrosive media occasions,but the pipe may lose effectiveness in the process of transporting hot and cold media,so the research of stress distribution and variation in polyethylene-steel composite pipes is very *** article first assume that a thin adhesive layer is in between the polyethylene and steel,the adhesive layer along the axial shear stress is the major cause of the polyethylene layer and the steel pipe off ***,we use a method of finite element to computer simulation by ANSYS,and verify initial ***,based on simulation data,we analyse the adhesive layer stress distribution and the variation with different parameters to *** the above research,preliminarily summarize the variation and distribution of interlaminar stress,and provide technical support for future design and process improvement of polyethylenesteel pipe.

关键词： Laminated Polyethylene-steel Composite pipes Interlaminar Stress Finite elements ANSYS

Performance Evaluation of Gated pipes Technique for Improving Surface Irrigation Efficiency in Maize Hybrids

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Agricultural Sciences 2015年第5期6卷 550-570页

作者： Osama A. M. Ali Ahmed S. H. Mohammed Crop Science Department Faculty of Agriculture Minufiya University Shebin El-Kom Egypt Irrigation Department Agricultural Engineering Research Institute ARC Giza Egypt

Waterlogging and low application efficiency are the main problems inherent with surface irrigation in the Nile Delta. Develop surface irrigation using gated pipes (GP) is a new method to be used to distribute water into furrow irrigated fields as strategy based on water saving. Laboratory calibration was conducted out to evaluate the hydraulic characteristics of pipe gates. Field experiments were conducted at the Experimental Farm of the Agriculture Faculty, Minufiya University during 2013 and 2014 seasons to evaluate the performance of utilize gated pipes technique for irrigating five maize varieties (S.C 10, S.C 130, S.C 131, S.C 2031 and T.W.C 321). The results revealed that the highest amount of water applied was with traditional surface irrigation (6423.81 m3·ha-1. Use of gated pipes system GP1 as compared to traditional irrigation reduced water application by 923.81 m3·ha-1 with grain and stover yields increases of 5.7% and 3.4%, respectively. Traditional irrigation system achieved lowest irrigation performance parameters compared to gated pipes systems. Maize physiological attributes, yield, water use efficiency (WUE) and nitrogen accumulation were significantly decreased by either deficit or surplus irrigation than of GP1 rate. S.C 2031 variety significantly surpassed other varieties in abovementioned traits. Significant interaction effects were detected in both seasons. Maize varieties respond differently to irrigation systems. The highest values of grain yield (11062.6 and 10911.8 kg·ha-1 and stover yield (13639.0 and 13902.2 kg·ha-1) were obtained by S.C 2031 irrigated with GP1 system in both seasons. From the above mentioned results, it is concluded that the gated pipes technique is better than traditional irrigation for improving WUE and maize productivity under Nile Delta conditions.

关键词： Maize Hybrids Gated pipes Irrigation Efficiency