The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Lysandros Pantelidis - One of the best experts on this subject based on the ideXlab platform.
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A Critical Review of Schmertmann’s Strain Influence Factor Method for Immediate Settlement Analysis
Geotechnical and Geological Engineering, 2019Co-Authors: Lysandros PantelidisAbstract:This paper offers an in-depth review of Schmertmann’s strain Influence Factor method for immediate settlement analysis. The method in question is among the most popular worldwide, whilst, it is included in various important design codes worldwide (e.g. Eurocode 7, FHWA NHI-06-089). As shown, Schmertmann’s method has been proposed without proper and adequate documentation, whilst it presents serious weaknesses related to its calibration and the values adopted for various Factors used. In addition, comparison between measured and calculated settlement values of structures or full-size test footings (data taken from independent studies) indicates that Schmertmann’s method is a poor prediction tool. In this respect, an integrated index is suggested for the quantification of the “effectiveness” of the various settlement analysis methods (including the Schmertmann’s one). This consists of the mean and the coefficient of variation of the calculated over the measured settlement ratio values and the percentage of the cases for which the calculated settlement results greater than or equal to the measured settlement. The very low “effectiveness” index values obtained gave rise to investigating the possible sources of error. A parametric finite element analysis was, finally, carried out for supporting the main findings.
Jian Kang - One of the best experts on this subject based on the ideXlab platform.
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thermal comfort range and Influence Factor of urban pedestrian streets in severe cold regions
Energy and Buildings, 2019Co-Authors: Hong Jin, Jian Kang, Siqi LiuAbstract:Abstract This study investigated thermal comfort on two urban pedestrian streets in Harbin, which is an extremely cold region with significant temperature variability, through an on-site survey to determine the thermal comfort range and Influence Factor. The results show that the ‘acceptable’ votes above 80% in Harbin are in the range of −3.8–23.0 °C universal thermal climate index (UTCI). The neutral temperatures in transition and hot seasons are 21.4 °C and 21.8 °C UTCI, respectively, and participants are more sensitive to the thermal environment during the hot season. The thermal sensation vote values of the preferred temperatures in transition and hot seasons are 0.48 and 0.65, respectively. This indicates that people expect a ‘neutral ∼ slightly warm’ thermal sensation. The modified UTCI range in Harbin is wider compared to those in Tianjin and the Mediterranean, whereas the UTCI for extreme cold stress reaches −30.2 °C. Thermal adaptation and demographic Factors also have a significant impact on thermal comfort. Working people always feel colder than walking people, and in the cold season, people who have lived in Harbin longer feel more comfortable. Males feel more comfortable than females, whereas older people are more adaptable to extreme weather conditions.
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study on erosion wear of fracturing pipeline under the action of multiphase flow in oil gas industry
Journal of Natural Gas Science and Engineering, 2016Co-Authors: Jixin Zhang, Jian KangAbstract:Abstract During hydraulic fracturing operations, pipelines are especially prone to particle erosion caused by high-rate pumping fracturing fluid. Previous studies likely ignore the stress state of equipment during the erosion wear process. In this study, fracturing pipeline erosion was evaluated under the action of multiphase flow through both experimental study and computational fluid dynamics (CFD) simulation. Firstly, a new erosion wear test rig which can apply tensile stress on erosion samples was developed to indicate the failure mechanism and main parameters of erosion Influence Factor. The results indicate the erosion wear was greatly Influenced by different states of stress. Secondly, according to the experimental results and fluid dynamic theory, the flow mode and erosion simulation model were established. The flow characteristic of particles in fracturing pipe can be described as comprehensive effects of centrifugal force, turbulent diffusion, main stream and secondary flow carrying effect. Based on the CFD simulation, the erosion distribution of pipes was also obtained. Finally, the correlation of erosion wear results from CFD simulation, experimental study, and field situation was validated in this study.
L I Shunguo - One of the best experts on this subject based on the ideXlab platform.
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research of unsafe Factors of 44 monosulfuron plus propazine wp on foxtail millet
Journal of Hebei Agricultural Sciences, 2012Co-Authors: L I ShunguoAbstract:Aim to the phytotoxicity problem of the herbicide 44% monosulfuron plus propazine WP,six Influence Factors were compared by the orthogonal experiment method.The results showed that the most important Influence Factor on the safety was the spraying dose,then the sprinkler irrigation amount,soil moisture and soil preparation quality.The technical scheme was that 1 200 g/hm2 of spraying dose,flat soil preparation,and 15% of soil water content without irrigation.The unsafe Factors included 2 400 g/hm2 of spraying dose,35 mm of sprinkler irrigation amount,loose soil preparation,and soil water content ≤10% with sprinkler irrigation.
H U Chengguang - One of the best experts on this subject based on the ideXlab platform.
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the industry agglomeration industry convergence between province and metropolitan in yangzi river delta and the economic effect of industry convergence an positive study on the industry agglomeration evolution in yangzi river delta
Journal of Chongqing University, 2007Co-Authors: H U ChengguangAbstract:Industry agglomeration is an important character of economic development in Yangtze River delta.This paper,based on the general Influence Factor of industry agglomeration and the Yangtze River delta economy reality,analyzes the drive mechanism,the space evolution path and impact of industry agglomeration.According to the author,the drive force of industry agglomeration results from the regional competitive advantage,while the Influence Factor of industry agglomeration from economic geography theories just deepens and enlarges the industry agglomeration process;the industry convergence in Yangtze River delta is the space evolution characteristic of industry agglomeration,which was shaped by the Yangtze River delta history,the regional competitive advantage and the open and reform policy of China.This paper also agrees with that the industry convergence based on industry agglomeration doesn't form "the repeated investment of industry" or "the destroyed market competition",and the externality,market effect and price effect,which result from the industry agglomeration on the basis of the comparison advantage of cheap labor in the world economy,make the industry convergence in Yangtze River delta have positive results.However,the regional industrialization progress has a negative impact to the related industry in the Yangtze River.The positive research testifies above-mentioned conclusions.
Dewen Zhao - One of the best experts on this subject based on the ideXlab platform.
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limit analysis based on gm criterion for defect free pipe elbow under internal pressure
International Journal of Mechanical Sciences, 2014Co-Authors: Shunhu Zhang, Xiaonan Wang, Binna Song, Dewen ZhaoAbstract:Abstract Analytical solution of limit load for a defect-free pipe elbow is obtained under internal pressure using GM (geometric midline), in which the strain hardening effect has been taken into account. The limit load is a function of ratio of thickness to radius t0/r0, strain hardening exponent n, curvature Influence Factor m and ultimate tensile strength. Comparison with FE and analytical results of other investigators was performed. Although the limit loads calculated by GM criterion are little higher than the traditional analytical results, the GM results are in good agreement with FE results. Besides, the effect of different criteria, strain hardening exponent, ratio of thickness to radius, as well as curvature Influence Factor on the limit loads are also discussed systematically.
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limit analysis of defect free pipe elbow under internal pressure with mean yield criterion
Journal of Iron and Steel Research International, 2013Co-Authors: Shunhu Zhang, Dewen Zhao, Cairu Gao, Guodong WangAbstract:With mean yield (MY) criterion, an analytical solution of the collapse load for a defect-free pipe elbow under internal pressure is first obtained. It is a function of ratio of thickness to radius t0/r0, strain hardening exponent n, curvature Influence Factor m and ultimate tensile strength. The collapse load increases with the increase of m, and it is the same as the burst pressure of straight pipe if m = 1 is assumed. The MY-based solution is compared with those based on Tresca, Mises and twin shear stress (TSS) yield criteria, and the comparison indicates that Tresca and twin shear stress yield criteria predict a lower bound and an upper bound to the collapse load respectively. However, the MY-based solution lies just between the TSS and Tresca solutions, and almost has the same precision with the Mises solution.
