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Analysis of catchment evapotranspiration at different scales using bottom-up and top-down approaches

Xiangyu XU, Dawen YANG,

《结构与土木工程前沿（英文）》 2010年 第4卷 第1期   页码 65-77 doi: 10.1007/s11709-010-0002-9

摘要： Physically-based hydrological models are used to predict catchment water balance through detailed simulation of hydrological processes at small temporal and spatial scales. However, annual catchment water balance can also be easily and simply predicted using lumped conceptual model. Comparison between physically-based hydrological models and lumped conceptual models can help us understand the dominant factors on catchment water balance at different scales. In this paper, a distributed physically-based hydrological model (i.e., bottom-up approach) and a simple water-energy balance model (i.e., top-down approach) are used to predict actual evapotranspiration in nine sub-catchments, and the whole basin of the Luan River in northern China. Both simulations give very close values of annual evapotranspiration and show the same complementary relationship between actual and potential evapotranspiration at annual time scale. From the analysis at different time scales through comparison of the top-down and the bottom-up methods, it is shown that the annual catchment evapotranspiration is controlled mainly by annual precipitation and potential evapotranspiration, and the variability of soil water and vegetation becomes more important at a smaller time scale in the study areas. It is also known that the relationship between potential and actual evapotranspiration shows a highly nonlinear relationship at the annual and catchment scale but can be simplified to a linear relationship at hourly temporal and hillslope scales, which is commonly used in the physically-based hydrological models.

关键词： catchment evapotranspiration     distributed hydrological model     water-energy balance model     top-down and bottom-up approaches    

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Water, energy and food interactions–Challenges and opportunities

Gustaf OLSSON

《环境科学与工程前沿（英文）》 2013年 第7卷 第5期   页码 787-793 doi: 10.1007/s11783-013-0526-z

摘要： Water and energy are inextricably linked, and as a consequence both have to be addressed together. This is called the water-energy nexus. When access to either is limited, it becomes obvious that it is necessary to consider their interdependence. Population growth, climate change, urbanization, increasing living standards and food consumption will require an integrated approach where food, water and energy security are considered together. In this paper we examine water, energy and food security and their couplings. The nexus also creates conflicts between water use, energy extraction and generation as well as food production. Some of these conflicts are illustrated. It is argued that there is an urgent need for integrated planning and operation. Not only will better technology be needed, but also better integration of policies, organizations and political decisions.

关键词： water security     energy security     food security     water-energy nexus     water conflicts    

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Quantitative analysis of yield and soil water balance for summer maize on the piedmont of the North China

Jingjing WANG,Feng HUANG,Baoguo LI

《农业科学与工程前沿（英文）》 2015年 第2卷 第4期   页码 295-310 doi: 10.15302/J-FASE-2015074

摘要： The North China Plain (NCP) is a major grain production area in China, but the current winter wheat-summer maize system has resulted in a large water deficit. This water-shortage necessitates the improvement of crop water productivity in the NCP. A crop water model, AquaCrop, was adopted to investigate yield and water productivity (WP) for rain-fed summer maize on the piedmont of the NCP. The data sets to calibrate and validate the model were obtained from a 3-year (2011–2013) field experiment conducted on the Yanshan piedmont of the NCP. The range of root mean square error (RMSE) between the simulated and measured biomass was 0.67–1.25 t·hm , and that of relative error (RE) was 9.4%–15.4%, the coefficient of determination ( ) ranged from 0.992 to 0.994. The RMSE between the simulated and measured soil water storage at depth of 0–100 cm ranged from 4.09 to 4.39 mm; and RE and in the range of 1.07%–1.20% and 0.880–0.997, respectively. The WP as measured by crop yield per unit evapotranspiration was 2.50–2.66 kg·m . The simulated impact of long-term climate (i.e., 1980–2010) and groundwater depth on crop yield and WP revealed that the higher yield and WP could be obtained in dry years in areas with capillary recharge from groundwater, and much lower values elsewhere. The simulation also suggested that supplementary irrigation in areas without capillary groundwater would not result in groundwater over-tapping since the precipitation can meet the water required by both maize and ecosystem, thus a beneficial outcome for both food and ecosystem security can be assured.

关键词： AquaCrop     summer maize     soil water balance     water productivity    

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Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

《化学科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 162-172 doi: 10.1007/s11705-009-0267-5

摘要： Bubble columns are widely used in chemical and biochemical processes due to their excellent mass and heat transfer characteristics and simple construction. However, their fundamental hydrodynamic behaviors, which are essential for reactor scale-up and design, are still not fully understood. To develop design tools for engineering purposes, much research has been carried out in the area of computational fluid dynamics (CFD) modeling and simulation of gas-liquid flows. Due to the importance of the bubble behavior, the bubble size distribution must be considered in the CFD models. The population balance model (PBM) is an effective approach to predict the bubble size distribution, and great efforts have been made in recent years to couple the PBM into CFD simulations. This article gives a selective review of the modeling and simulation of bubble column reactors using CFD coupled with PBM. Bubble breakup and coalescence models due to different mechanisms are discussed. It is shown that the CFD-PBM coupled model with proper bubble breakup and coalescence models and interphase force formulations has the ability of predicting the complex hydrodynamics in different flow regimes and, thus, provides a unified description of both the homogeneous and heterogeneous regimes. Further study is needed to improve the models of bubble coalescence and breakup, turbulence modification in high gas holdup, and interphase forces of bubble swarms.

关键词： bubble column     computational fluid dynamics     bubble breakup and coalescence     population balance model     bubble size distribution    

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Nonlinear sealing force of a seawater balance valve used in an 11000-meter manned submersible

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0726-y

摘要： Balance valve is a core component of the 11000-meter manned submersible “struggle,” and its sealing performance is crucial and challenging when the maximum pressure difference is 118 MPa. The increasing sealing force improves the sealing performance and increases the system’s energy consumption at the same time. A hybrid analytical–numerical–experimental (ANE) model is proposed to obtain the minimum sealing force, ensuring no leakage at the valve port and reducing energy consumption as much as possible. The effects of roundness error, environmental pressure, and materials on the minimum sealing force are considered in the ANE model. The basic form of minimum sealing force equations is established, and the remaining unknown coefficients of the equations are obtained by the finite element method (FEM). The accuracy of the equation is evaluated by comparing the independent FEM data to the equation data. Results of the comparison show good agreement, and the difference between the independent FEM data and equation data is within 3% when the environmental pressure is 0–118 MPa. Finally, the minimum sealing force equation is applied in a balance valve to be experimented using a deep-sea simulation device. The balance valve designed through the minimum sealing force equation is leak-free in the experiment. Thus, the minimum sealing force equation is suitable for the ultrahigh pressure balance valve and has guiding significance for evaluating the sealing performance of ultrahigh pressure balance valves.

关键词： seawater balance valve     sealing performance     hybrid ANE model     FEM     minimum sealing force equation    

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Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0676-4

摘要： The control system presently used in shield posture rectification is based on driver experience, which is marginally reliable. The study of the related theory is flawed. Therefore, a decision-making approach for the deviation correction trajectory and posture rectification load for an earth pressure balance (EPB) shield is proposed. A calculation model of posture rectification load of an EPB shield is developed by considering the interactions among the cutter head, shield shell, and ground. The additional position change during the shield attitude correction is highlighted. The posture rectification loads and shield behaviors results can be solved by the proposed method. The influences of the stratum distribution (i.e., bedrock height in the upper-soft and lower-hard strata) on shield behaviors and posture rectification loads are analyzed. Results indicated that the increase of pitch angle in the upper-soft and lower-hard strata causes a sharp rise in vertical displacement. The bedrock height increases the magnitudes of the required posture rectification moments when hr/D > 0.5. For a tunnel with hr/D ≤ 0.5, the variation of hr/D has little effect on the posture rectification moments. Finally, the posture rectifying curves based on the theoretical model are compared with the target ones based on the double circular arc interpolation method. The required results can be obtained regardless of the soil–rock compound stratum distribution. The maximum rectification moment in the rock layer is almost 12.6 times that in the soil layer. Overall, this study provides a valuable reference for moment determination and the trajectory prediction of posture rectification in compound strata.

关键词： additional position change     deviation correction trajectory     earth pressure balance shield     mechanical model     posture rectification    

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Cleaning the energy sources for water heating among Nanjing households: barriers and opportunities for

Lingyun ZHU,Beibei LIU,Jun BI

《环境科学与工程前沿（英文）》 2014年 第8卷 第5期   页码 757-766 doi: 10.1007/s11783-013-0603-3

摘要： Energy for water heating accounts for an increasing part in residential energy demand in China. An extensive survey was conducted to analyze the determinants of household energy choices for water heaters among residents in Nanjing, China. Two sets of variables were examined as potential influences: building features and household socio-economic characteristics. Results suggest that building features such as gas availability and building structures, and household characteristics such as household head’s education degree and energy-conserving sense are crucial determinants in choosing natural gas as water heater energy. Installation permission for solar water heater, building stories, and residential location serve as determining factors in choosing solar water heaters. Based on these, barriers and opportunities are discussed for transitions toward cleaner water heating energies, and suggestions are given for local governments to promote cleaner energy replacement in China.

关键词： residential energy demand     water heating     multinomial logit model    

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Modeling effects of a tidal barrage on water quality indicator distribution in the Severn Estuary

Guanghai GAO, Roger A. FALCONER, Binliang LIN

《环境科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 211-218 doi: 10.1007/s11783-012-0464-1

摘要： In this study, emphasis has focused on assessing the potential hydro-environmental impacts of a barrage across the Severn Estuary, with a numerical model being developed and applied to the estuary to assess the impacts of proposed Severn Barrage on the hydrodynamic, sediment transport and faecal indicator organism distribution within the estuary. The results show that the Severn Barrage has the potential to reduce the tidal currents in a highly dynamic estuary. This leads to the reduction of suspended sediment concentrations, which in turn affects the bacterial transport processes which is highly related to the sediment transport processes.

关键词： water quality indicator     Severn Estuary     numerical model     tidal energy    

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Leptin signaling and leptin resistance

null

《医学前沿（英文）》 2013年 第7卷 第2期   页码 207-222 doi: 10.1007/s11684-013-0263-5

摘要：

Leptin is secreted into the bloodstream by adipocytes and is required for the maintenance of energy homeostasis and body weight. Leptin deficiency or genetic defects in the components of the leptin signaling pathways cause obesity. Leptin controls energy balance and body weight mainly through leptin receptor b (LEPRb)-expressing neurons in the brain, particularly in the hypothalamus. These LEPRb-expressing neurons function as the first-order neurons that project to the second-order neurons located within and outside the hypothalamus, forming a neural network that controls the energy homeostasis and body weight. Multiple factors, including inflammation and endoplasmic reticulum (ER) stress, contribute to leptin resistance. Leptin resistance is the key risk factor for obesity. This review is focused on recent advance about leptin action, leptin signaling, and leptin resistance.

关键词： leptin signaling     leptin receptor     energy balance     leptin resistance     obesity    

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水平衡与国土空间协调发展战略研究

胡庆芳,陈秀敏,高娟,金君良,王银堂,张建云

《中国工程科学》 2022年 第24卷 第5期   页码 63-74 doi: 10.15302/J-SSCAE-2022.05.009

摘要：

构建健康水平衡是提升水土资源匹配性、促进国土空间高质量发展的基础，而科学系统保护与集约高效利用国土空间是实现健康水平衡、保障国家水安全的根本途径。鉴于我国水资源与生产力要素分布极不匹配、国土空间发展中未有效落实量水发展的情况，本文面向生态文明建设和国土空间规划需求，以“实现健康水平衡、促进国土空间高质量发展”为目标，根据“山水林田湖草”系统治理、水陆统筹的原则，构建了以“理清约束条件、制定控制目标，完善基础设施、优化时空配置，科学严格保护、系统综合整治，集聚协调开发、高效集约利用”为主要内容的水平衡与国土空间协调发展战略。最后，提出了系统监测评价水平衡状态、提升国家尺度水土资源匹配性、优化“三生”空间划分和科学务实绿化国土等重点建议。

关键词： 健康水平衡；国土空间；协调发展；综合应对战略；生态保护修复；高效集约利用    

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How did Archimedes discover the law of buoyancy by experiment?

Hidetaka KUROKI

《机械工程前沿（英文）》 2016年 第11卷 第1期   页码 26-32 doi: 10.1007/s11465-016-0368-z

摘要：

After Archimedes and Vitruvius era, for more than 2000 years, it has been believed that the displaced water measurement of golden crown is impossible, and at his Eureka moment, Archimedes discovered the law of buoyancy (Proposition 7 of his principles) and proved the theft of a goldsmith by weighing the golden crown in water.

A previous study showed that a small amount of displaced water was able to be measured with enough accuracy by the introduced method. Archimedes measured the weight of displaced water. He did not find the law of buoyancy but rather specific gravity of things at the moment.

After which, Archimedes continued to measure the specific gravity of various solids and fluids. Through these measurements, he reached the discovery of the law of buoyancy directly by experiment. In this paper, the process to the discovery of Archimedes’ principle (Proposition 5) is presented.

关键词： Archimedes’ principle     buoyancy     specific gravity     Eureka     Vitruvius     displaced water     balance     floating body    

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Cloud-Model-Based Feature Engineering to Analyze the Energy–Water Nexus of a Full-Scale Wastewater Treatment

Shan-Shan Yang,Xin-Lei Yu,Chen-Hao Cui,Jie Ding,Lei He,Wei Dai,Han-Jun Sun,Shun-Wen Bai,Yu Tao,Ji-Wei Pang,Nan-Qi Ren,

《工程（英文）》 doi: 10.1016/j.eng.2022.02.011

摘要： Wastewater treatment plants (WWTPs) are important and energy-intensive municipal infrastructures. High energy consumption and relatively low operating performance are major challenges from the perspective of carbon neutrality. However, water–energy nexus analysis and models for WWTPs have rarely been reported to date. In this study, a cloud-model-based energy-consumption analysis (CMECA) of a WWTP was conducted to explore the relationship between influent and energy consumption by clustering its influent’s parameters. The principal component analysis (PCA) and K-means clustering were applied to classify the influent condition using water quality and volume data. The energy consumption of the WWTP is divided into five standard evaluation levels, and its cloud digital characteristics (CDCs) were extracted according to bilateral constraints and golden ratio methods. Our results showed that the energy consumption distribution gradually dispersed and deviated from the Gaussian distribution with decreased water concentration and quantity. The days with high energy efficiency were extracted via the clustering method from the influent category of excessive energy consumption, represented by a compact-type energy consumption distribution curve to identify the influent conditions that affect the steady distribution of energy consumption. The local WWTP has high energy consumption with 0.3613 kW·h·m−3 despite low influent concentration and volumes, across four consumption levels from low (I) to relatively high (IV), showing an unsatisfactory operation and management level. The average oxygenation capacity, internal reflux ratio, and external reflux ratio during high energy efficiency days recognized by further clustering were obtained (0.2924–0.3703 kg O2·m−3, 1.9576–2.4787 and 0.6603–0.8361, respectively), which could be used as a guide for the days with low energy efficiency. Consequently, this study offers a water–energy nexus analysis method to identify influent conditions with operational management anomalies and can be used as an empirical reference for the optimized operation of WWTPs.

关键词： Wastewater treatment plants     Cloud-model theory     Data mining     Principal component analysis     K     -means clustering     Cloud-model-based energy-consumption analysis    

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面向 2050 年我国农业资源平衡与国际进口潜力研究

郑海霞,尤飞,罗其友,唐华俊

《中国工程科学》 2022年 第24卷 第1期   页码 20-28 doi: 10.15302/J-SSCAE-2022.01.003

摘要：

受农业高质量发展、食物消费结构转型升级、气候变化的多重影响，我国农业资源供需平衡日益趋紧，因而统筹利用国际国内两种资源、两个市场，保障我国中长期粮食安全至关重要。本文在对比分析国内、国际农业资源的基础上，研究了我国2035 年和2050 年的粮食消费需求、消费结构、供给结构，分析了未来农业资源供需缺口以及虚拟水、虚拟耕地的可进口潜力与进口来源地，据此展望了我国农业水土资源利用的目标。研究表明：我国虚拟耕地进口将在2048 年前后达到峰值，需进口虚拟耕地近6.147×107 hm2；虚拟水进口量在2045 年前后达到峰值，虚拟水进口量为1.136×108 m3（以蓝水估算），约为2017 年全国农业总用水量的30%；可增加的耕地进口潜力主要来自南美洲和非洲。

关键词： 农业资源平衡     食物消费结构     虚拟水     虚拟耕地     进口潜力    

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Hybrid energy harvesting systems for self-powered sustainable water purification by harnessing ambientenergy

《环境科学与工程前沿（英文）》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1718-9

摘要：

● Energy harvesters harness multiple energies for self-powered water purification.

关键词： Piezocatalysis     Solar energy     Waste heat     Decentralized water treatment     Point-of-use     Nanogenerator    

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Gut microbial balance and liver transplantation: alteration, management, and prediction

null

《医学前沿（英文）》 2018年 第12卷 第2期   页码 123-129 doi: 10.1007/s11684-017-0563-2

摘要：

Liver transplantation is a conventional treatment for terminal stage liver diseases. However, several complications still hinder the survival rate. Intestinal barrier destruction is widely observed among patients receiving liver transplant and suffering from ischemia–reperfusion or rejection injuries because of the relationship between the intestine and the liver, both in anatomy and function. Importantly, the resulting alteration of gut microbiota aggravates graft dysfunctions during the process. This article reviews the research progress for gut microbial alterations and liver transplantation. Especially, this work also evaluates research on the management of gut microbial alteration and the prediction of possible injuries utilizing microbial alteration during liver transplantation. In addition, we propose possible directions for research on gut microbial alteration during liver transplantation and offer a hypothesis on the utilization of microbial alteration in liver transplantation. The aim is not only to predict perioperative injuries but also to function as a method of treatment or even inhibit the rejection of liver transplantation.

关键词： gut microbial balance     liver transplantation     ischemia–reperfusion     acute rejection    

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标题 作者 时间 类型 操作

Analysis of catchment evapotranspiration at different scales using bottom-up and top-down approaches

Xiangyu XU, Dawen YANG,

期刊论文

Water, energy and food interactions–Challenges and opportunities

Gustaf OLSSON

期刊论文

Quantitative analysis of yield and soil water balance for summer maize on the piedmont of the North China

Jingjing WANG,Feng HUANG,Baoguo LI

期刊论文

Simulation of bubble column reactors using CFD coupled with a population balance model

Tiefeng WANG

期刊论文

Nonlinear sealing force of a seawater balance valve used in an 11000-meter manned submersible

期刊论文

Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

期刊论文

Cleaning the energy sources for water heating among Nanjing households: barriers and opportunities for

Lingyun ZHU,Beibei LIU,Jun BI

期刊论文

Modeling effects of a tidal barrage on water quality indicator distribution in the Severn Estuary

Guanghai GAO, Roger A. FALCONER, Binliang LIN

期刊论文

Leptin signaling and leptin resistance

null

期刊论文

水平衡与国土空间协调发展战略研究

胡庆芳,陈秀敏,高娟,金君良,王银堂,张建云

期刊论文

How did Archimedes discover the law of buoyancy by experiment?

Hidetaka KUROKI

期刊论文

Cloud-Model-Based Feature Engineering to Analyze the Energy–Water Nexus of a Full-Scale Wastewater Treatment

Shan-Shan Yang,Xin-Lei Yu,Chen-Hao Cui,Jie Ding,Lei He,Wei Dai,Han-Jun Sun,Shun-Wen Bai,Yu Tao,Ji-Wei Pang,Nan-Qi Ren,

期刊论文

面向 2050 年我国农业资源平衡与国际进口潜力研究

郑海霞,尤飞,罗其友,唐华俊

期刊论文

Hybrid energy harvesting systems for self-powered sustainable water purification by harnessing ambientenergy

期刊论文

Gut microbial balance and liver transplantation: alteration, management, and prediction

null

期刊论文