检索结果-南通市图书馆

Calculation of Mass Concrete Temperature and Creep Stress under the Influence of Local Air Heat Transfer

Computer Modeling in engineering & Sciences 2024年第9期140卷 2977-3000页

作者： Heng Zhang Chao Su Xiaohu Chen Zhizhong Song Weijie Zhan Academy of Science and Technology Changjiang Institute of Survey Planning Design and ResearchWuhan430010China College of Water Conservancy and Hydropower engineering Hohai UniversityNanjing210098China Chief engineer Office Wujiang Company of Goupitan Power Construction CooperationYuqing564408China

Temperature-induced cracking during the construction of mass concrete is a significant *** simulations of concrete temperature have primarily assumed that the concrete is placed in an open *** problem of heat transfer between the air and concrete has been simplified to the concrete’s heat dissipation ***,in the case of tubular concrete structures,where air inlet and outlet are relatively limited,the internal air temperature does not dissipate promptly to the external environment as it *** accurately simulate the temperature and creep stress in tubular concrete structures with enclosed air spaces during construction,we establish an air–concrete coupled heat transfer model according to the principles of conjugate heat transfer,and the accuracy of the model is verified through ***,we conduct a case study to analyze the impact of airflow within the ship lock corridor on concrete temperature and creep *** results demonstrate that enhancing airflow within the corridor can significantly reduce the maximum concrete *** with cases in which airflow within the corridor is neglected,the maximum concrete temperature and maximum tensile stress can be reduced by 12.5°C and 0.7 MPa,respectively,under a wind speed of 4 m/*** results of the traditional calculation method are relatively close to those obtained at a wind speed of 1 m/***,the temperature reduction process in the traditional method is faster,and the method yields greater tensile stress values for the corridor location.

关键词： Conjugate heat transfer temperature field mass concrete creep stress

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A methodology for damage evaluation of underground tunnels subjected to static loading using numerical modeling

引用

Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 1993-2005页

作者： Shahriyar Heidarzadeh Ali Saeidi Rock Mechanics engineer AtkinsRéalisMontrealQuebecCanada Department of Applied Sciences Universitédu QuébecàChicoutimiChicoutimiQuebecCanada

We have proposed a methodology to assess the robustness of underground tunnels against potential *** involves developing vulnerability functions for various qualities of rock mass and static loading *** account for these variations,we utilized a Monte Carlo Simulation(MCS)technique coupled with the finite difference code FLAC^(3D),to conduct two thousand seven hundred numerical simulations of a horseshoe tunnel located within a rock mass with different geological strength index system(GSIs)and subjected to different states of static *** quantify the severity of damage within the rock mass,we selected one stress-based(brittle shear ratio(BSR))and one strain-based failure criterion(plastic damage index(PDI)).Based on these criteria,we then developed fragility ***,we used mathematical approximation techniques to produce vulnerability functions that relate the probabilities of various damage states to loading intensities for different quality classes of blocky rock *** results indicated that the fragility curves we obtained could accurately depict the evolution of the inner and outer shell damage around the ***,we have provided engineers with a tool that can predict levels of damages associated with different failure mechanisms based on variations in rock mass quality and in situ stress *** method is a numerically developed,multi-variate approach that can aid engineers in making informed decisions about the robustness of underground tunnels.

关键词： Fragility curves Underground tunnels Vulnerability functions Brittle damage FLAC3D Numerical modeling

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Active Magnetic Compensation Based on Parametric Resonance Magnetometer

引用

Journal of Shanghai Jiaotong university(Science) 2024年第2期29卷 280-289页

作者：郭阳李绍良黄艺明骆曼箬刘华 School of Electronic Information and Electrical engineering Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Institute of Spacefight Control Technology Shanghai Key Laboratory of Space Intelligent Control TechnologyShanghai Engineer Research Center of InertiaShanghai 201109China

Based on the parametric resonance magnetometer(PRM)theory,this paper establishes an experimen-tal system of *** experimental results are consistent with the theoretical predictions.A PRM has been developed with sensitivity of 0.5 pT/Hz^(1/2),which can detect the magnitude of residual magnetic field;furthermore,a proportion-integration-differentiation(PID)closed-loop magnetic compensation system of the residual magnetic field also has been *** with open-loop compensation,the PID closed-loop compensation reduces the average value of the residual magnetic field in the z-axis direction from 0.0244nT to-0.0023nT,and the mean-square error from 0.2083 nT to 0.0691 *** the same way,the average value of the residual magnetic field in the y-axis direction is reduced from 0.0816nT to-0.0042nT,and the mean-square error from 0.1316nT to 0.0461 *** magnitude of residual magnetic fields in both directions is decreased to the order of picotesla(pT).In addition,based on the signal waveforms of the magnetometer,a method of verifying the effect of magnetic compensation is proposed.

关键词： magnetometer parametric resonance nuclear magnetic resonance gyroscope magnetic compensa-tion proportion-integration-differentiation(PID)

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Calculation of Mass Concrete Temperature Containing Cooling Water Pipe Based on Substructure and Iteration Algorithm

引用

工程与科学中的计算机建模(英文) 2024年第1期138卷 813-826页

作者： Heng Zhang Chao Su Zhizhong Song Zhenzhong Shen Huiguang Lei Changjiang Institute of Survey PlanningDesign and ResearchWuhan430010China College ofWater Conservancy and Hydropower engineering Hohai UniversityNanjing210098China Chief engineer Office Wujiang Company of Goupitan Power Construction CooperationYuqing564408China

Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and *** such equation is the Fourier equation,which is a commonly used and effective method for evaluating the effectiveness of temperature control measures for mass *** important measure for temperature control in mass concrete is the use of cooling water ***,the mismatch of grids between large-scale concrete models and small-scale cooling pipe models can result in a significant waste of calculation time when using the finite element ***,the temperature of the water in the cooling pipe needs to be iteratively calculated during the thermal transfer *** substructure method can effectively solve this problem,and it has been validated by *** Abaqus/Python secondary development technology provides engineers with enough flexibility to combine the substructure method with an iteration algorithm,which enables the creation of a parametric modeling calculation for cooling water *** paper proposes such a method,which involves iterating the water pipe boundary and establishing the water pipe unit substructure to numerically simulate the concrete temperature field that contains a cooling water *** verify the feasibility and accuracy of the proposed method,two classic numerical examples were *** results showed that this method has good applicability in cooling pipe *** the value of the iteration parameterαis 0.4,the boundary temperature of the cooling water pipes can meet the accuracy requirements after 4∼5 iterations,effectively improving the computational ***,this approach provides a useful tool for engineers to analyze the temperature control measures accurately and efficiently for mass concrete,such as cooling water pipes,using Abaqus/Python secondary development.

关键词： Fourier equation cooling water pipe mass concrete iteration algorithm

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A novel responsive stabilizing Janus nanosilica as a nanoplugging agent in water-based drilling fluids for exploiting hostile shale environments

引用

Petroleum Science 2024年第2期21卷 1190-1210页

作者： Alain Pierre Tchameni Lv-Yan Zhuo Lesly Dasilva Wandji Djouonkep Robert Dery Nagre Lu-Xin Chen Lin Zhao Chao Ma Bin-Qiang Xie College of Petroleum engineering Yangtze UniversityWuhan430100HubeiChina Key Laboratory of Drilling and Production engineering for Oil and Gas HubeiChina Lost Circulation Control Laboratory National Engineering Laboratory for Petroleum Drilling EngineeringYangtze UniversityWuhan430100HubeiChina College of Petroleum engineering Shandong Institute of Petroleum and Chemical TechnologyDongying257061ShandongChina Petroleum engineer research Institute of Petrochina Dagang Oilfield Tianjin300280China Department of Chemical engineering Kumasi Technical UniversityP.O.Box 854KumasiGhana

Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not been very effective in high-temperature drilling operations. Thermo-responsive Janus nanocomposites are expected to strongly interact with clay particles from the inward hemisphere of nanomaterials, which drive the establishment of a tighter hydrophobic membrane over the shale surface at the outward hemisphere under geothermal conditions for shale stabilization. This work combines the synergistic benefits of thermo-responsive and zwitterionic nanomaterials to synchronously enhance the chemical inhibitions and plugging performances in shale under harsh conditions. A novel thermoresponsive Janus nanosilica(TRJS) exhibiting zwitterionic character was synthesized, characterized,and assessed as shale stabilizer for WBDFs at high temperatures. Compared to pristine nanosilica(Si NP)and symmetrical thermo-responsive nanosilica(TRS), TRJS exhibited anti-polyelectrolyte behaviour, in which electrolyte ions screened the electrostatic attraction between the charged particles, potentially stabilizing nanomaterial in hostile shaly environments(i.e., up to saturated brine or API brine). Macroscopically, TRJS exhibited higher chemical inhibition than Si NP and TRS in brine, prompting a better capability to control pressure penetration. TRJS adsorbed onto the clay surface via chemisorption and hydrogen bonding, and the interactions became substantial in brine, according to the results of electrophoretic mobility, surface wettability, and X-ray diffraction. Thus, contributing to the firm trapping of TRJS into the nanopore structure of the shale, triggering the formation of a tight hydrophobic membrane over the shale surface from the outward hemisphere. The addition of TRJS into WBDF had no deleterious effect on fluid properties after hot-treatment at 190℃, implying that TRJ

关键词： Janus nanosilica Thermo-responsive copolymer Anti-polyelectrolyte effect Shale stabilizer Inhibition Plugging Drilling fluid

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

珠海市城市设计数字化管控研究

引用

China City Planning Review 2024年第1期33卷 79-86页

作者：周作江 Registered Consulting engineer Natural Resources and Planning Technology CenterZhuhaiP.R.China

With China's urbanization entering a stage of high-quality development,refined urban governance has become an important part in the modernization of governance capacity,in which urban design plays a major *** paper briefly reviews the background of urban design digi-talization and discusses the issues that need to be addressed in digital management and control of urban design in *** this basis,the paper summarizes the practice of digital management and control of urban design in Zhuhai in three aspects:building a rule base for digital management and control,developing a 3D quantitative analysis method for urban space from the macro,meso,and micro perspectives,and establishing a digital urban design management platform and storing 2D and 3D urban design schemes in the database according to unified standards,so as to realize the standardized management,intelligent review,and scientific decision-making of urban design.

关键词： urban design digital management and control high-quality space Zhuhai

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Deciphering the population structure and genetic basis of growth traits from whole-genome resequencing of the leopard coral grouper(Plectropomus leopardus)

引用

Zoological research 2024年第2期45卷 329-340页

作者： Shao-Xuan Wu Qi-Fan Zeng Wen-Tao Han Meng-Ya Wang Hui Ding Ming-Xuan Teng Ming-Yi Wang Pei-Yu Li Xin Gao Zhen-Min Bao Bo Wang Jing-Jie Hu MOE Key Laboratory of Marine Genetics and Breeding College of Marine Life Sciences/Key Laboratory of Tropical Aquatic Germplasm of Hainan ProvinceSanya Oceanographic InstitutionOcean University of ChinaQingdaoShandong/SanyaHainan 266100/572025China Hainan Seed Industry Laboratory SanyaHainan 572025China Southern Marine Science and engineer Guangdong Laboratory GuangzhouGuangdong 511458China

The leopard coral grouper(Plectropomus leopardus)is a species of significant economic *** artificial cultivation of *** has thrived in recent decades,the advancement of selective breeding has been hindered by the lack of comprehensive population genomic *** this study,we identified over 8.73 million single nucleotide polymorphisms(SNPs)through whole-genome resequencing of 326 individuals spanning six distinct ***,we categorized 226 individuals with high-coverage sequencing depth(≥14×)into eight clusters based on their genetic profiles and phylogenetic ***,four of these clusters exhibited pronounced genetic differentiation compared with the other *** identify potentially advantageous loci for ***,we examined genomic regions exhibiting selective sweeps by analyzing the nucleotide diversity(θπ)and fixation index(FST)in these four *** these high-coverage resequencing data,we successfully constructed the first haplotype reference panel specific to *** achievement holds promise for enabling high-quality,***,we combined low-coverage sequencing data with imputation techniques for a genome-wide association study,aiming to identify candidate SNP loci and genes associated with growth traits.A significant concentration of these genes was observed on chromosome 17,which is primarily involved in skeletal muscle and embryonic development and cell ***,our detailed investigation of growth-related SNPs across the eight clusters revealed that cluster 5 harbored the most promising candidate SNPs,showing potential for genetic selective breeding *** findings provide a robust toolkit and valuable insights into the management of germplasm resources and genome-driven breeding initiatives targeting ***.

关键词： Plectropomus leopardus Whole-genome resequencing Growth Haplotype reference panel Single nucleotide polymorphisms

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Oxygen vacancy engineering for tuning the catalytic activity of LaCoO_(3) perovskite

引用

Journal of Rare Earths 2024年第3期42卷 506-514,I0003页

作者： Jeong Hyun Cho Minjae Kim Inchan Yang Kyung Tae Park Chang Houn Rhee Hai Woong Park Ji Chul Jung Department of Chemical engineering Myongji UniversityYongin 17058Republic of Korea Institute of Advanced Composite Materials Korea Institute of Science and TechnologyWanju-gunJeollabuk-do 55324Republic of Korea Iron&Steel Process engineering research Group POSCOPohang 37859Republic of Korea Hydrogen research Center Research Institute of Industrial Science&Technology(RIST)Pohang 37673Republic of Korea

Herein, we attempted to engineer oxygen vacancies on the surface of LaCoO_(3) perovskite through simple post-treatments(acid or reductive thermal treatments). Acid treatment induces oxygen vacancies through the selective etching of the La cations, whereas thermal treatment in a reducing atmosphere generates oxygen vacancies by directly removing lattice oxygen. The characterization results confirm that the number of surface oxygen vacancies, which are crucial in various catalytic oxidation reactions,considerably increases in the LaCoO_(3) catalysts treated with acid or reducing gas. Acid treatment enriches the oxygen vacancies while maintaining the structure of the LaCoO_(3) catalysts, which can not be achieved through reductive thermal treatment. Therefore, the acid treatment is considered a promising technique for oxygen vacancy engineering of perovskite catalysts for tuning their catalytic activities. Furthermore,the catalytic activities of the posttreated LaCoO_(3) catalysts for CO oxidation were evaluated and are noted to be considerably better than those of the pristine LaCoO_(3) catalyst due to their abundant oxygen vacancies. Consequently, we conclude that the oxygen vacancies of perovskite catalysts can be effectively engineered via two simple methods and play a significant role in CO oxidation.

关键词： LaCoO_(3)perovskite Acid treatment Reductive thermal treatment Oxygen vacancy CO oxidation Rare earths

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Measurements of coupled fluid and sediment motion over mobile sand dunes in a laboratory flume

引用

International Journal of Sediment research 2008年第4期23卷 329-337页

作者： Daniel G.WREN Roger A.KUHNLE research hydraulic engineer USD A-ARS-National Sedimentation LaboratoryPh.D research hydraulic engineer USD A-ARS-National Sedimentation Laboratory

The relationship between turbulent fluid motions and sediment particle motions over mobile sand dunes was investigated by using a laser Doppler velocimeter and an acoustic backscatter system in laboratory experiments performed at the USDA-ARS-National Sedimentation Laboratory. Profiles of acoustic backscatter from particles and at-a-point turbulence data were collected while translating both measurement devices downstream at the speed of mobile dune bedforms. The resulting data set was used to examine the frequency (recurrence frequency) at which the fluctuating backscatter and fluid velocity signals exceeded magnitude thresholds based on the standard deviation (σ) of the local velocity and the magnitude the acoustic signal resulting from backscatter from suspended particles. The slope of the downstream and vertical velocity recurrence frequencies generally indicated a gradually increasing recurrence time with increasing elevation. The recurrence frequency for acoustic backscatter data was not strongly variable with elevation. The closest correspondence between the recurrence frequencies of sediment backscatter and vertical velocities at the 1σ magnitude threshold was in a region defined by X/L<0.4 and y<6 cm. The downstream velocity was most closely related to backscatter in a small region at 0.4

关键词： Turbulence Suspended sediment Acoustic backscatter Dunes

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Runoff reduction due to environmental changes in the Sanchuanhe river basin

引用

International Journal of Sediment research 2008年第2期23卷 174-180页

作者： Guoqing WANG1,Jianyun ZHANG2,Ruimin HE3,Naiqian JIANG4,and Xin'ai JING5 1 Senior engineer,State Key Laboratory of Hydrology-Water Resources and hydraulic engineering,Nanjing hydraulic research Institute,Nanjing 210098,China research Center for Climate Change,MWR,Nanjing 210029,China Yellow River Institute of hydraulic research,Zhengzhou 450003,China 2 Prof.,3 engineer,State Key Laboratory of Hydrology-Water Resources and hydraulic engineering,Nanjing hydraulic research Institute,Nanjing 210098,China 4 Prof.,5 engineer,Yellow River Institute of hydraulic research,Zhengzhou 450003,China Senior engineer State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research Institute Nanjing 210098 China research Center for Climate Change MWR Nanjing 210029 China Yellow River Institute of hydraulic research Zhengzhou 450003 China Prof. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research Institute Nanjing 210098 China engineer State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research Institute Nanjing 210098 China Prof. Yellow River Institute of Hydraulic Research Zhengzhou 450003 China engineer Yellow River Institute of Hydraulic Research Zhengzhou 450003 China

Recently,runoff in many river basins in China has been ***,the role that climate change and human activities are playing in this decrease is currently of *** this study,we evaluated an assessment method that was designed to quantitatively separate the effects of climate change and human activities on runoff in river ***,we calibrated the SIMHYD rainfall runoff model using naturally recorded hydro-meteorologic data pertaining to the Sanchuanhe River basin and then determined the effects of climate change and human activities on runoff by comparing the estimated natural runoff that occurred during the period in which humans disturbed the basin to the runoff that occurred during the period prior to disturbance by *** results of this study revealed that the SIMHYD rainfall runoff model performs well for estimating monthly *** addition,we found that absolute runoff reductions have increased in response to human activities and climate change,with average reductions of 70.1% and 29.9% in total runoff being caused by human activities and climate change,*** together,the results of this study indicate that human activities are the primary cause of runoff reduction in the Sanchuanhe River basin.

关键词： Sanchuanhe River Hydrological simulation Climate change Human activities Impact

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：