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Substance flow analysis for an urban drainage system of a representative hypothetical city in China

Hua BAI, Siyu ZENG, Xin DONG, Jining CHEN

《环境科学与工程前沿（英文）》 2013年 第7卷 第5期   页码 746-755 doi: 10.1007/s11783-013-0551-y

摘要： This paper discusses the use of substance flow analysis (SFA) as a tool to support quantified research on urban drainage systems. Based on the principle of mass balance, a static substance flow model is established to describe and examine the routes and intensities of water, chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) for a representative hypothetical city (RH city) in China, which is a devised and scaled city using statistical characteristics of urban circumstances at the national level. It is estimated that the annual flux of water, COD, TN and TP through the urban drainage system in 2010 was 55.1 million m , 16037.3 t, 1649.5 t and 209.7 t, respectively. The effluent of wastewater treatment plant (WWTP) was identified as the most important pathway for pollutant emissions, which contributed approximately 60% of COD, 65% of TN and 50% of TP to receiving water. During the wastewater treatment process, 1.0 million m , 7042.5 t, 584.2 t and 161.4 t of the four studied substances had been transmitted into sludge, meanwhile 3813.0 t of COD and 394.0 t of TN were converted and emitted to the atmosphere. Compared with the representative hypothetical city of 2000, urban population and the area of urban built districts had expanded by approximately 90% and 80% respectively during the decade, resulting in a more than threefold increase in the input of substances into the urban drainage system. Thanks to the development of urban drainage systems, the total loads of the city were maintained at a similar level.

关键词： substance flow analysis (SFA)     urban drainage system     representative hypothetical city (RH city)     water pollution control    

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REGIONAL ASSESSMENT OF SOIL NITROGEN MINERALIZATION IN DIVERSE CROPLAND OF A REPRESENTATIVE INTENSIVE

《农业科学与工程前沿（英文）》 2023年 第10卷 第4期   页码 530-540 doi: 10.15302/J-FASE-2023515

摘要：

Soil nitrogen mineralization (Nmin) is a key process that converts organic N into mineral N that controls soil N availability to plants. However, regional assessments of soil Nmin in cropland and its affecting factors are lacking, especially in relation to variation in elevation. In this study, a 4-week incubation experiment was implemented to measure net soil Nmin rate, gross nitrification (Nit) rate and corresponding soil abiotic properties in five field soils (A–C, maize; D, flue-cured tobacco; and E, vegetables; with elevation decreasing from A to E) from different altitudes in a typical intensive agricultural area in Dali City, Yunnan Province, China. The results showed that soil Nmin rate ranged from 0.10 to 0.17 mg·kg−1·d−1 N, with the highest value observed in field E, followed by fields D, C, B, and A, which indicated that soil Nmin and Nit rates varied between fields, decreasing with elevation. The soil Nit rate ranged from 434.2 to 827.1 µg·kg−1·h−1 N, with the highest value determined in field D, followed by those in fields E, C, B, and A. The rates of soil Nmin and Nit were positively correlated with several key soil parameters, including total soil N, dissolved organic carbon and dissolved inorganic N across all fields, which indicated that soil variables regulated soil Nmin and Nit in cropland fields. In addition, a strong positive relationship was observed between soil Nmin and Nit. These findings provide a greater understanding of the response of soil Nmin among cropland fields related to spatial variation. It is suggested that the soil Nmin from cropland should be considered in the evaluation of the N transformations at the regional scale.

关键词： cropland     gross nitrification rate     regulatory factors     soil nitrogen mineralization     spatial variation    

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increasing numbers of RE-inverters on the power quality in the distribution grids: A PQ case study of a representative

Przemyslaw JANIK, Grzegorz KOSOBUDZKI, Harald SCHWARZ

《能源前沿（英文）》 2017年 第11卷 第2期   页码 155-167 doi: 10.1007/s11708-017-0469-3

摘要： This paper presents the selected power quality (PQ) indicia of a wind generator and a photovoltaic installation considered to be the representative of medium voltage and low voltage distribution grids. The analysis of measured values suggests that the decrease in PQ is a case of specific combination of distributed generation, grid parameters and load behaviour. Modern generators have a limited impact on PQ. On the other hand, fluctuations in power generation are regarded as an emerging PQ indicator. The growing number of distributed renewable installations causes stochastic, variable, and hardly predictable power flows in the distribution grid. The nature of fluctuations in wind and solar generation is different. In both cases, new indexes for the quantification of fluctuations are needed and are yet not standardised. Proper assessment of these fluctuations enables definition of useful fluctuation limits and rules for optimal storage system integration.

关键词： power quality     harmonics     sags     photovoltaic(PV) system     doubly feed induction generator (DFIG)     inverters    

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Thermal and catalytic pyrolysis of a synthetic mixture representative of packaging plastics residue

Simona Colantonio, Lorenzo Cafiero, Doina De Angelis, Nicolò M. Ippolito, Riccardo Tuffi, Stefano Vecchio Ciprioti

《化学科学与工程前沿（英文）》 2020年 第14卷 第2期   页码 288-303 doi: 10.1007/s11705-019-1875-3

摘要： A synthetic mixture of real waste packaging plastics representative of the residue from a material recovery facility (plasmix) was submitted to thermal and catalytic pyrolysis. Preliminary thermogravimetry experiments coupled with Fourier transform infrared spectroscopy were performed to evaluate the effects of the catalysts on the polymers’ degradation temperatures and to determine the main compounds produced during pyrolysis. The thermal and catalytic experiments were conducted at 370°C, 450°C and 650°C using a bench scale reactor. The oil, gas, and char yields were analyzed and the compositions of the reaction products were compared. The primary aim of this study was to understand the effects of zeolitic hydrogen ultra stable zeolite Y (HUSY) and hydrogen zeolite socony mobil-5 (HZSM5) catalysts with high silica content on the pyrolysis process and the products’ quality. Thermogravimetry showed that HUSY significantly reduces the degradation temperature of all the polymers—particularly the polyolefines. HZSM5 had a significant effect on the degradation of polyethylene due to its smaller pore size. Mass balance showed that oil is always the main product of pyrolysis, regardless of the process conditions. However, all pyrolysis runs performed at 370°C were incomplete. The use of either zeolites resulted in a decrease in the heavy oil fraction and the prevention of wax formation. HUSY has the best performance in terms of the total monoaromatic yield (29 wt-% at 450°C), while HZSM5 promoted the production of gases (41 wt-% at 650°C). Plasmix is a potential input material for pyrolysis that is positively affected by the presence of the two tested zeolites. A more effective separation of polyethylene terephthalate during the selection process could lead to higher quality pyrolysis products.

关键词： packaging plastics waste     plasmix     pyrolysis     zeolite catalyst     degradation temperature    

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Computational model generation and RVE design of self-healing concrete

Md. Shahriar QUAYUM,Xiaoying ZHUANG,Timon RABCZUK

《结构与土木工程前沿（英文）》 2015年 第9卷 第4期   页码 383-396 doi: 10.1007/s11709-015-0320-z

摘要： Computational homogenization is a versatile tool that can extract effective properties of heterogeneous or composite material through averaging technique. Self-healing concrete (SHC) is a heterogeneous material which has different constituents as cement matrix, sand and healing agent carrying capsules. Computational homogenization tool is applied in this paper to evaluate the effective properties of self-healing concrete. With this technique, macro and micro scales are bridged together which forms the basis for multi-scale modeling. Representative volume element (RVE) is a small (microscopic) cell which contains all the microphases of the microstructure. This paper presents a technique for RVE design of SHC and shows the influence of volume fractions of different constituents, RVE size and mesh uniformity on the homogenization results.

关键词： homogenization     self-healing concrete (SHC)     representative volume element     multiscale modelling    

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Critical flow-storm approach to total maximum daily load (TMDL) development: an analytical conceptual model

Zhang Harry, Yu Shaw

《环境科学与工程前沿（英文）》 2008年 第2卷 第3期   页码 267-273 doi: 10.1007/s11783-008-0058-0

摘要： One of the key challenges in the total maximum daily load (TMDL) development process is how to define the critical condition for a receiving waterbody. The main concern in using a continuous simulation approach is the absence of any guarantee that the most critical condition will be captured during the selected representative hydrologic period, given the scarcity of long-term continuous data. The objectives of this paper are to clearly address the critical condition in the TMDL development process and to compare continuous and event-based approaches in defining critical condition during TMDL development for a waterbody impacted by both point and nonpoint source pollution. A practical, event-based critical flow-storm (CFS) approach was developed to explicitly addresses the critical condition as a combination of a low stream flow and a storm event of a selected magnitude, both having certain frequencies of occurrence. This paper illustrated the CFS concept and provided its theoretical basis using a derived analytical conceptual model. The CFS approach clearly defined a critical condition, obtained reasonable results and could be considered as an alternative method in TMDL development.

关键词： representative hydrologic     occurrence     simulation approach     scarcity     alternative    

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Current progress on internal medicine in China—2006 Part II

YAO Dingkang, ZHU Liang, YU Renqian, MEI Changlin

《医学前沿（英文）》 2007年 第1卷 第4期   页码 343-351 doi: 10.1007/s11684-007-0066-7

摘要： A lot of progress has been made on internal medicine in the past year. Here a great deal of data were collected about internal medicine in China by searching for some most important medicine magazines published in China in 2006. Because there are so many articles on internal medicine, some representative reports were selected and further reviewed. In the part II, a summary of advances made in four branches includes nephrology, hematology, endocrinology and metabolism, rheumatology.

关键词： endocrinology     rheumatology     hematology     nephrology     representative    

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视频分层组织方案和技术

章毓晋,陆海斌

《中国工程科学》 2000年 第2卷 第3期   页码 18-22

摘要：

数字视频是多媒体信息系统中重要的数据类型。传统的视频表示方法仅是一个时间序列一媒体流， 所以对计算机来说，很难在内容层次上认知视频。为了有效地访问和利用视频信息，合适的视频数据组织非常 重要。文章提出将视频划分成四个层次即视频节目、情节、镜头和图像帧的组织方法。这样一种分层结构提供了紧凑和有意义的视频目录，方便了视频非线性浏览和基于内容的检索。为了得到这样一种组织，不仅要检测 出镜头和情节这些视频单元的边界，还要提取镜头关键帧和选择情节有代表性的镜头和代表帧。文章介绍一系 列分割视频和组织视频的准则和方法，并把它们结合起来组成了一个原型实验系统。文中还给出了一些对实际 视频进行组织的结果，它们表明该组织形式是非常有效的。

关键词： 视频组织     浏览     镜头     关键帧     情节     代表帧    

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混凝土中碱硅反应效应的多尺度均质化分析 Article

Roozbeh Rezakhani, Mohammed Alnaggar, Gianluca Cusatis

《工程（英文）》 2019年 第5卷 第6期   页码 1139-1154 doi: 10.1016/j.eng.2019.02.007

摘要：

碱硅反应（ASR）是混凝土结构（如桥梁和水坝）在长期的高湿度环境下发生的主要劣化机制之一。ASR是骨料中活性硅成分与水泥浆中碱金属离子之间发生的一种化学反应。这种化学反应会产生ASR凝胶，该凝胶吸水后膨胀，造成混凝土损坏和开裂，最终导致混凝土力学性能下降。本研究基于晶格离散粒子模型（LDPM），研究了混凝土的ASR损伤。LDPM可在粗骨料尺度上模拟混凝土，它是一种中尺度力学模型。作者已经成功地利用LDPM框架对ASR建模，并且通过实验数据对所得模型ASR-LDPM进行了校准和验证。本研究将ASR-LDPM用作中尺度模型，并采用最新开发的多尺度均质化框架来模拟ASR的宏观尺度效应。作者首先分析了由ASR-LDPM模拟的混凝土代表性体积元（RVE）在拉伸和压缩两种情况下的均质化行为，并研究了ASR对混凝土有效力学性能的影响。接下来，作者利用已开发的均质化框架再现了关于混凝土棱柱体自由体积膨胀的实验数据。最后，作者通过中尺度模型和所提出的多尺度方法，评估了压缩和四点弯曲梁中棱柱体的强度退化现象，以分析后者的准确性和计算效率。在所有数值分析中，作者考虑了具有不同内部粒子划分的RVE大小，以探讨它们对均质化响应的影响。

关键词： 多尺度均质化     代表性体积元     碱硅反应     晶格离散粒子模型    

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Two-scale modeling of granular materials: A FEM-FEM approach

Yun-Zhu CAI, Yu-Ching WU

《结构与土木工程前沿（英文）》 2013年 第7卷 第3期   页码 304-315 doi: 10.1007/s11709-013-0213-y

摘要： In the present paper, a homogenization-based two-scale FEM-FEM model is developed to simulate compactions of visco-plastic granular assemblies. The granular structure consisting of two-dimensional grains is modeled by the microscopic finite element method at the small-scale level, and the homogenized viscous assembly is analyzed by the macroscopic finite element method at large-scale level. The link between scales is made using a computational homogenization method. The two-scale FEM-FEM model is developed in which each particle is treated individually with the appropriate constitutive relations obtained from a representative volume element, kinematic conditions, contact constraints, and elimination of overlap satisfied for every particle. The method could be used in a variety of problems that can be represented using granular media.

关键词： homogenization     two-scale     representative volume element     compaction     granular assembly     finite element method    

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Schedule refinement for homogeneousmulti-core processors in the presence of manufacturing-caused heterogeneity

Zhi-xiang CHEN,Zhao-lin LI,Shan CAO,Fang WANG,Jie ZHOU

《信息与电子工程前沿（英文）》 2015年 第16卷 第12期   页码 1018-1033 doi: 10.1631/FITEE.1500035

摘要： Multi-core homogeneous processors have been widely used to deal with computation-intensive embedded applications. However, with the continuous down scaling of CMOS technology, within-die variations in the manufacturing process lead to a significant spread in the operating speeds of cores within homogeneous multi-core processors. Task scheduling approaches, which do not consider such heterogeneity caused by within-die variations, can lead to an overly pessimistic result in terms of performance. To realize an optimal performance according to the actual maximum clock frequencies at which cores can run, we present a heterogeneity-aware schedule refining (HASR) scheme by fully exploiting the heterogeneities of homogeneous multi-core processors in embedded domains. We analyze and show how the actual maximum frequencies of cores are used to guide the scheduling. In the scheme, representative chip operating points are selected and the corresponding optimal schedules are generated as candidate schedules. During the booting of each chip, according to the actual maximum clock frequencies of cores, one of the candidate schedules is bound to the chip to maximize the performance. A set of applications are designed to evaluate the proposed scheme. Experimental results show that the proposed scheme can improve the performance by an average value of 22.2%, compared with the baseline schedule based on the worst case timing analysis. Compared with the conventional task scheduling approach based on the actual maximum clock frequencies, the proposed scheme also improves the performance by up to 12%.

关键词： Schedule refining     Multi-core processor     Heterogeneity     Representative chip operating point    

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人体胃肠道–菌群相互作用的工程学研究模型

Marc Mac Giolla Eain, Joanna Baginska, Kacy Greenhalgh, Joëlle V. Fritz, Frederic Zenhausern, Paul Wilmes

《工程（英文）》 2017年 第3卷 第1期   页码 60-65 doi: 10.1016/J.ENG.2017.01.011

摘要：

研究宿主–胃肠道微生物的相互作用已经成为管理人类健康和疾病的关键组成部分。微生理系统的发展正在为研究人员提供前所未有的对于这种复杂关系的获取和理解。这些系统结合了微型工程、微流体和细胞培养的优点，来创建人类肠道中普遍存在的环境条件。在这里我们提出的HuMiX(人类微生物交联对话) 平台，是一个利用这种多学科方法提供具有代表性的人体胃肠道的体外模型系统，用于研究宿主–微生物分子的相互作用。我们总结了使用该平台获得的概念验证结果，强调其对于大大增强我们对宿主–微生物相互作用了解的潜力，且其可能对药物、食品和营养以及医疗保健行业产生的巨大影响。同时讨论了这些技术面临的一些关键问题和挑战。

关键词： 微生物     微流体     肠道芯片     HuMiX    

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标题 作者 时间 类型 操作

Substance flow analysis for an urban drainage system of a representative hypothetical city in China

Hua BAI, Siyu ZENG, Xin DONG, Jining CHEN

期刊论文

REGIONAL ASSESSMENT OF SOIL NITROGEN MINERALIZATION IN DIVERSE CROPLAND OF A REPRESENTATIVE INTENSIVE

期刊论文

increasing numbers of RE-inverters on the power quality in the distribution grids: A PQ case study of a representative

Przemyslaw JANIK, Grzegorz KOSOBUDZKI, Harald SCHWARZ

期刊论文

Thermal and catalytic pyrolysis of a synthetic mixture representative of packaging plastics residue

Simona Colantonio, Lorenzo Cafiero, Doina De Angelis, Nicolò M. Ippolito, Riccardo Tuffi, Stefano Vecchio Ciprioti

期刊论文

Computational model generation and RVE design of self-healing concrete

Md. Shahriar QUAYUM,Xiaoying ZHUANG,Timon RABCZUK

期刊论文

Critical flow-storm approach to total maximum daily load (TMDL) development: an analytical conceptual model

Zhang Harry, Yu Shaw

期刊论文

Current progress on internal medicine in China—2006 Part II

YAO Dingkang, ZHU Liang, YU Renqian, MEI Changlin

期刊论文

视频分层组织方案和技术

章毓晋,陆海斌

期刊论文

混凝土中碱硅反应效应的多尺度均质化分析

Roozbeh Rezakhani, Mohammed Alnaggar, Gianluca Cusatis

期刊论文

Two-scale modeling of granular materials: A FEM-FEM approach

Yun-Zhu CAI, Yu-Ching WU

期刊论文

Schedule refinement for homogeneousmulti-core processors in the presence of manufacturing-caused heterogeneity

Zhi-xiang CHEN,Zhao-lin LI,Shan CAO,Fang WANG,Jie ZHOU

期刊论文

人体胃肠道–菌群相互作用的工程学研究模型

Marc Mac Giolla Eain, Joanna Baginska, Kacy Greenhalgh, Joëlle V. Fritz, Frederic Zenhausern, Paul Wilmes

期刊论文