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Distribution, characteristics and daily fluctuations of microplastics throughout wastewater treatment

《环境科学与工程前沿(英文)》 2022年 第16卷 第1期   页码 6-6 doi: 10.1007/s11783-021-1440-4

摘要:

• MPs were analyzed throughout three WWTPs with mixed domestic–industrial influents.

关键词: Microplastic     Wastewater treatment plant     Mixed domestic-industrial influent     Characteristic     Daily fluctuation    

Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

Binrong WEN, Sha WEI, Kexiang WEI, Wenxian YANG, Zhike PENG, Fulei CHU

《机械工程前沿(英文)》 2017年 第12卷 第3期   页码 321-332 doi: 10.1007/s11465-017-0434-1

摘要:

The magnitude and stability of power output are two key indices of wind turbines. This study investigates the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine. First, wind speed models, particularly the wind shear model and the tower shadow model, are described in detail. The widely accepted tower shadow model is modified in view of the cone-shaped towers of modern large-scale wind turbines. Power fluctuation and power loss due to wind shear and tower shadow are analyzed by performing theoretical calculations and case analysis within the framework of a modified version of blade element momentum theory. Results indicate that power fluctuation is mainly caused by tower shadow, whereas power loss is primarily induced by wind shear. Under steady wind conditions, power loss can be divided into wind farm loss and rotor loss. Wind farm loss is constant at 3α(3α−1)R2/(8H2). By contrast, rotor loss is strongly influenced by the wind turbine control strategies and wind speed. That is, when the wind speed is measured in a region where a variable-speed controller works, the rotor loss stabilizes around zero, but when the wind speed is measured in a region where the blade pitch controller works, the rotor loss increases as the wind speed intensifies. The results of this study can serve as a reference for accurate power estimation and strategy development to mitigate the fluctuations in aerodynamic loads and power output due to wind shear and tower shadow.

关键词: wind turbine     wind shear     tower shadow     power fluctuation     power loss    

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

《能源前沿(英文)》 2012年 第6卷 第1期   页码 89-97 doi: 10.1007/s11708-012-0176-z

摘要: This paper discusses two problems in in-line particle sizing when using light fluctuation method. First, by retrieving the ratio of particle concentrations at different time, the intensity of incident light is obtained. There exists narrow error between the calculated and pre-detected value of the intensity of incident light. Secondly, by combining spectrum analysis with Gregory’s theory, a multi-sub-size zone model is proposed, with which the relationship between the distribution of turbidity and the particle size distribution (PSD) can be established, and an algorithm developed to determine the distribution of turbidity. Experiments conducted in the laboratory indicate that the measured size distribution of pulverized coal conforms well with the imaging result.

关键词: in-line measurement     particle size distribution (PSD)     incident light intensity     particle concentration     light fluctuation    

Evaluation of SWAT sub-daily runoff estimation at small agricultural watershed in Korea

Ganga Ram Maharjan, Youn Shik Park, Nam Won Kim, Dong Seok Shin, Jae Wan Choi, Geun Woo Hyun, Ji-Hong Jeon, Yong Sik Ok, Kyoung Jae Lim

《环境科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 109-119 doi: 10.1007/s11783-012-0418-7

摘要: A study was undertaken for the prediction of runoff flow from 0.8 ha field-sized agricultural watershed in South Korea using Soil and Water Assessment Tool (SWAT) sub-daily. The SWAT model with sub-daily configuration predicted flow from the watershed within the range of acceptable accuracy. The SWAT sub-daily simulations were carried out for a total of 18 rainfall events, 9 each for calibration and validation. Overall trend and extent of matching simulated flow for the rainfall events in 2007-2008 with measured data during the calibration process were coefficient of determination ( ) value of 0.88 and Nash and Sutcliffe Efficiency ( ) value of 0.88. For validation, and values were 0.9 and 0.84, respectively. Whereas and values for simulation results using daily rainfall data were 0.79 and -0.01, respectively, that were observed to be out of acceptable limits for the model simulation. The importance of higher time resolution (hourly) precipitation records for flow simulation were evaluated by comparing and with 15 min, 2 h, 6 h and 12 h precipitation data, which resulted in lower statistics with increases in time resolution of precipitation data. The SWAT sub-daily sensitivity analysis was performed with the consideration of hydraulic parameter and was found as in the rank order of CN2 (curve number), ESCO (soil evaporation compensation factor), GW_DELAY (ground water delay time), ALPHA_BF ( base flow alpha factor), GWQMN ( a threshold minimum depth of water in the shallow aquifer required for return flow to occur) , REVAPMN (minimum depth of water in shallow aquifer for re-evaporation to occur) , LAT_TIME (lateral flow travel time) respectively. These sensitive parameters were evaluated at 10% higher and lower values of the parameters, corresponding to 70.5% higher and 23.2% lower in simulated flow out from the SWAT model. From the results obtained in this study, hourly precipitation record for SWAT sub-daily with Green-Ampt infiltration method was proven to be efficient for runoff estimation at field sized watershed with higher accuracies that could be efficiently used to develop site-specific Best Management Practices (BMPs) considering rainfall intensity, rather than simply using daily rainfall data.

关键词: Soil and Water Assessment Tool (SWAT)     sub-daily simulation     runoff     rainfall    

价值工程在日化企业产品开发中的应用

陈志祥,张国兴

《中国工程科学》 2005年 第7卷 第6期   页码 84-87

摘要:

越来越多的企业开始从产品和市场推广竞争转向产品源头竞争,即通过降低产品开发成本,提高产品开发速度,价值工程是降低开发成本的行之有效的方法;以广东高露洁公司为背景,介绍了日化企业利用价值工程降低产品开发成本的做法。

关键词: 日化企业     产品开发     价值工程    

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

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    

利用地球同步轨道InSAR每日生成DEM的质量分析 Article

杨泽发, 张庆君, 丁晓利, 陈武

《工程(英文)》 2020年 第6卷 第8期   页码 913-918 doi: 10.1016/j.eng.2020.07.003

摘要:

最新的数字高程模型(DEM)产品在灾害防治、城市管理等诸多领域中扮演着重要角色。利用机载或低地球轨道(LEO)的星载干涉合成孔径雷达(InSAR)生成DEM已被证明是可行且极具价值的方法。然而,受成本和卫星重返周期的限制,该技术难以频繁(如每天)生成或更新大区域范围(如大陆尺度或更大范围)的DEM。由于对地同步合成孔径雷达(GEOSAR)卫星运行于地球静止轨道,因此它们能以相当短的重返时间(每天或更短)观测同一地面区域,这为实现生成每日DEM这一理想但目前难以实现的目标提供了潜在可能。为此,本文系统地分析了利用GEOSAR卫星生成的每日DEM产品质量。结果表明:GEOSAR卫星生成的每日DEM产品精度通常远低于利用传统低轨星载合成孔径雷达(SAR)获得的DEM产品。因此,研究GEOSAR DEM生成过程中的误差削弱方法显得至关重要。

关键词: 每日DEM生成     InSAR     地球同步SAR     精度分析    

基于同步波动原理的抗冲蚀弹性涂层设计

郭源君,肖华林,徐大清,李文斌

《中国工程科学》 2008年 第10卷 第9期   页码 60-63

摘要:

基于过流面冲蚀波纹形貌特征与流体边界层扰动波参数的对应关系,提出了实现弹性涂层边壁与边界层扰动波的同步波动,从而变边壁被动承受粒子冲击为主动回避与粒子的碰撞的抗冲蚀设计思想;分析了实现弹性涂层边壁与边界层扰动波同步波动的条件,并由此确定出弹性涂层的材料常数。

关键词: 冲蚀     边界层     弹性边壁     弹性涂层     同步波动    

峰谷电价体制下东北输油管网日输油优化研究

崔慧,吴长春,吴江林,孙青峰

《中国工程科学》 2004年 第6卷 第8期   页码 69-73

摘要:

东北原油长输管网是中国规模最大的地区性原油运输系统,就该管网基于峰谷电价体制下的运行现状,建立了线性规划数学模型,提出了日输油计划优化问题,并以铁秦线为例进行分析;初步揭示了峰谷电价体制下日输油计划方式的一些基本规律, 表明在该体制下东北管网具有一定的节能降耗潜力。但该方式在一定程度上受到管道本身运行特性的约束,与热油管道相比它更适合于等温管道。

关键词: 东北管网     峰谷电价     日输油     优化    

Optimal portfolio design of energy storage devices with financial and physical right market

《能源前沿(英文)》 2022年 第16卷 第1期   页码 95-104 doi: 10.1007/s11708-021-0788-2

摘要: With the continuous development of the spot market, in the multi-stage power market environment with the day-ahead market and right market, the study associated with the portfolio of energy storage devices requires that attention should be paid to transmission congestion and power congestion. To maximize the profit of energy storage and avoid the imbalance of power supply and consumption and the risk of node price fluctuation caused by transmission congestion, this paper presents a portfolio strategy of energy storage devices with financial/physical contracts. First, the concepts of financial/physical transmission rights and financial/physical storage rights are proposed. Then, the portfolio models of financial contract and physical contract are established with the conditional value-at-risk to measure the risks. Finally, the portfolio models are verified through the test data of the Pennsylvania-New Jersey-Maryland (PJM) electric power spot market, and the comparison between the risk aversion of portfolios based on financial/physical contract with the portfolio of the market without rights. The simulation results show that the portfolio models proposed in this paper can effectively avoid the risk of market price fluctuations.

关键词: portfolio     node price fluctuation     transmission right     energy storage right     risk aversion    

全球定位系统——建立太空卫星通信,改变地球上的日常生活

Peter Weiss

《工程(英文)》 2021年 第7卷 第3期   页码 290-303 doi: 10.1016/j.eng.2021.02.001

关键词: 工程成就    

Microplastics in municipal wastewater treatment plants: a case study of Denizli/Turkey

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1699-8

摘要:

● High amounts of microplastics are released to receiving media from WWTPs.

关键词: Microplastics     Wastewater treatment plant     Removal efficiency     Daily discharge    

Numerical simulation and analysis of periodically oscillating pressure characteristics of inviscid flow in a rolling pipe

Yan GU, Yonglin JU

《能源前沿(英文)》 2012年 第6卷 第1期   页码 21-28 doi: 10.1007/s11708-012-0173-2

摘要: Floating liquefied natural gas (LNG) plants are gaining increasing attention in offshore energy exploitation. The effects of the periodically oscillatory motion on the fluid flow in all processes on the offshore plant are very complicated and require detailed thermodynamic and hydrodynamic analyses. In this paper, numerical simulations are conducted by computational fluid dynamics (CFD) code combined with user defined function (UDF) in order to understand the periodically oscillating pressure characteristics of inviscid flow in the rolling pipe. The computational model of the circular pipe flow is established with the excitated rolling motion, at the excitated frequencies of 1–4 rad/s, and the excitated amplitudes of 3°–15°, respectively. The influences of flow velocities and excitated conditions on pressure characteristics, including mean pressure, frequency and amplitude are systematically investigated. It is found that the pressure fluctuation of the inviscid flow remains almost constant at different flow velocities. The amplitude of the pressure fluctuation increases with the increasing of the excitated amplitude, and decreases with the increasing of the excitated frequency. It is also found that the period of the pressure fluctuation varies with the excitated frequency. Furthermore, theoretical analyses of the flow in the rolling circular pipe are conducted and the results are found in qualitative agreement with the numerical simulations.

关键词: pressure fluctuation     rolling     floating production storage and offloading unit for liquefied natural gas (LNG-FPSO) offshore    

A novel high-temperature and high-pressure hydraulic pump based on mononeuron control

Linhui ZHAO, Xin FANG

《机械工程前沿(英文)》 2009年 第4卷 第2期   页码 219-223 doi: 10.1007/s11465-009-0024-y

摘要: Based on structures and characteristics of traditional hydraulic pumps, this paper proposes a novel high-temperature and high-pressure hydraulic pump (HHHP) that can work under 150°C and 28 MPa to overcome problems of traditional high-temperature plunger pumps. The HHHP is designed with the structure of mechanical division and double cylinder parallel. The control signals of two cylinders are two separate triangle waveforms with 90° phase difference. Because the output waveforms of two cylinders have the same characteristics as the control signals, the HHHP can obtain a stable output after two separate waveforms are superposed. A mononeuron self-adaptive PID control algorithm is also improved by modifying parameters and . Two improved controllers are used to control the two cylinders, respectively, making two displacements of plungers match each other. Therefore, reduced fluctuations and stable pressure output is obtained. Besides simulation, tests on the built prototype test system are carried out to verify the performance of HHHP. Results show that the improved control approach can limit fluctuations to a lower level and the HHHP system attains good outputs under different signal periods and different pressures.

关键词: mononeuron PID control     hydraulic pump     pressure fluctuation    

Removal of pharmaceutical and personal care products by sequential ultraviolet and ozonation process in a full-scale wastewater treatment plant

Qian SUI, Jun HUANG, Shuguang LU, Shubo DENG, Bin WANG, Wentao ZHAO, Zhaofu QIU, Gang YU

《环境科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 62-68 doi: 10.1007/s11783-013-0518-z

摘要: The application of appropriate advanced treatment process in the municipal wastewater treatment plants (WWTPs) has become an important issue considering the elimination of emerging contaminants, such as pharmaceutical and personal care products (PPCPs). In the present study, the removal of 13 PPCPs belonging to different therapeutic classes by the sequential ultraviolet (UV) and ozonation process in a full-scale WWTP in Beijing was investigated over the course of ten months. Most of the target PPCPs were effectively removed, and the median removal efficiencies of individual PPCPs, ranging from -13% to 89%, were dependent on their reaction rate constants with molecular ozone. Noticeable fluctuation in the removal efficiencies of the same PPCPs was observed in different sampling campaigns. Nevertheless, the sequential UV and ozonation process still made a significant contribution to the total elimination of most PPCPs in the full-scale WWTP, by compensating for the poor or fluctuant removal performance of PPCPs by biologic treatment process.

关键词: PPCPs     advanced treatment     ozone     fluctuation     removal contribution    

标题 作者 时间 类型 操作

Distribution, characteristics and daily fluctuations of microplastics throughout wastewater treatment

期刊论文

Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

Binrong WEN, Sha WEI, Kexiang WEI, Wenxian YANG, Zhike PENG, Fulei CHU

期刊论文

A novel light fluctuation spectrum method for in-line particle sizing

Shouxuan QIN, Xiaoshu CAI, Li MA

期刊论文

Evaluation of SWAT sub-daily runoff estimation at small agricultural watershed in Korea

Ganga Ram Maharjan, Youn Shik Park, Nam Won Kim, Dong Seok Shin, Jae Wan Choi, Geun Woo Hyun, Ji-Hong Jeon, Yong Sik Ok, Kyoung Jae Lim

期刊论文

价值工程在日化企业产品开发中的应用

陈志祥,张国兴

期刊论文

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

Zhang Harry, Yu Shaw

期刊论文

利用地球同步轨道InSAR每日生成DEM的质量分析

杨泽发, 张庆君, 丁晓利, 陈武

期刊论文

基于同步波动原理的抗冲蚀弹性涂层设计

郭源君,肖华林,徐大清,李文斌

期刊论文

峰谷电价体制下东北输油管网日输油优化研究

崔慧,吴长春,吴江林,孙青峰

期刊论文

Optimal portfolio design of energy storage devices with financial and physical right market

期刊论文

全球定位系统——建立太空卫星通信,改变地球上的日常生活

Peter Weiss

期刊论文

Microplastics in municipal wastewater treatment plants: a case study of Denizli/Turkey

期刊论文

Numerical simulation and analysis of periodically oscillating pressure characteristics of inviscid flow in a rolling pipe

Yan GU, Yonglin JU

期刊论文

A novel high-temperature and high-pressure hydraulic pump based on mononeuron control

Linhui ZHAO, Xin FANG

期刊论文

Removal of pharmaceutical and personal care products by sequential ultraviolet and ozonation process in a full-scale wastewater treatment plant

Qian SUI, Jun HUANG, Shuguang LU, Shubo DENG, Bin WANG, Wentao ZHAO, Zhaofu QIU, Gang YU

期刊论文