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The source and transport of bioaerosols in the air: A review

《环境科学与工程前沿(英文)》 2021年 第15卷 第3期 doi: 10.1007/s11783-020-1336-8

摘要:

• Emission of microbe from local environments is a main source of bioaerosols.

关键词: Bioaerosols     Diffusion     Source identification     Biogeography    

Identification and ranking of the risky organic contaminants in the source water of the Danjiangkou reservoir

Qingwei BU, Donghong WANG, Zijian WANG, Junnong GU

《环境科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 42-53 doi: 10.1007/s11783-013-0499-y

摘要: The Danjiangkou reservoir was selected to provide the source water for the middle routes of the South to North Water Transfer Project, which has provoked many environmental concerns. To date, investigations of water contamination of the source water of the Danjiangkou reservoir with organic micro-pollutants have been limited. This study was conducted to identify and rank organic contaminants that pose risks in the Danjiangkou reservoir. To this end, the Chemical Hazard Evaluation and Management Strategies (CHEMS-1) approach was adapted to integrate the deconvolution technology of qualitative identifying contaminants for site-specific environmental matrices. The samples were screened for the presence of 1093 contaminants using deconvolution technologies and the hazard values of the identified contaminants were calculated using the adapted CHEMS-1 approach according to their hazardous properties and occurrence in source water. The results showed that 46 contaminants from 1093 targets were present in Danjiangkou water, 23 of which appeared at frequencies higher than 50%, and 15 of which were identified as priorities. Over half (53%) of the high-ranked contaminants were polycyclic aromatic hydrocarbons (PAHs), with chrysene ranked highest on the list. Health risk assessment of the top-ranked PAHs was conducted and revealed that cancer risks of PAHs detected in the source water of Danjiangkou to different populations ranged from 10 to 10 , indicating a low cancer risk to consumers. The results of this study indicated that the adapted CHEMS-1 approach was feasible for site-specific screening of organic contaminants to identify and rank potential priority pollutants.

关键词: identification and ranking     source water     deconvolution     risk assessment     Danjiangkou     South to North Water Transfer Project    

Nitrogen pollution and source identification of urban ecosystem surface water in Beijing

Yufen REN, Zhiwei XU, Xinyu ZHANG, Xiaoke WANG, Xiaomin SUN, D. J. BALLANTINE, Shengzhong WANG

《环境科学与工程前沿(英文)》 2014年 第8卷 第1期   页码 106-116 doi: 10.1007/s11783-012-0474-z

摘要: Nitrogen contamination of surface water is a worldwide environmental problem with intensive agriculture and high population densities. We assessed the spatial and seasonal variation in concentrations of total nitrogen and different nitrogen species present in surface-water in Beijing, China. Also, chemical ( ) and isotopic ( ) indicators were used to identify nitrate sources. The results showed that, during 2009 and 2010, nitrate nitrogen concentrations ranged from 0.7 to 7.6 mg·L , ammonium nitrogen from 0.1 to 3.4 mg·L , and total nitrogen from 2.4 to 17.0 mg·L . Inorganic nitrogen accounted for between 60 and 100% of total nitrogen at the ten monitoring sites. Nitrate nitrogen, ammonium nitrogen, and total nitrogen concentrations at the 2 downstream monitoring sites in south-eastern Beijing were significantly higher than those at the other eight upstream monitoring sites ( <0.01). Examination of seasonal variation showed that there was a significant inverse relationship between nitrate nitrogen concentrations and precipitation, and that nitrate nitrogen concentrations peaked in the dry seasons. The information given by the values and nitrate nitrogen concentrations, combined with the ratio distribution, showed that domestic sewage was the major source of nitrate in Beijing. Methods to control and reduce sewage pollution are urgently needed to help manage surface water quality in Beijing.

关键词: nitrogen concentration     spatial and seasonal variation     stable nitrogen isotope     urban ecosystem     source    

Inverse uncertainty characteristics of pollution source identification for river chemical spill incidents

Jiping Jiang, Feng Han, Yi Zheng, Nannan Wang, Yixing Yuan

《环境科学与工程前沿(英文)》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1081-4

摘要:

Uncertainty rules of pollution source inversion are revealed by stochastic analysis

A release load is most easily inversed and source locations own largest uncertainty

Instantaneous spill assumption has much less uncertainty than continuous spill

The estimated release locations and times negatively deviate from real values

The new findings improve monitoring network design and emergency response to spills

关键词: River chemical spills     Emergency response     Pollution source inversion     Inverse uncertainty analysis     Regional Sensitivity Analysis method (RSA)     Monte Carlo analysis toolbox (MCAT)    

Mercury source zone identification using soil vapor sampling and analysis

David WATSON,Carrie MILLER,Brian LESTER,Kenneth LOWE,George SOUTHWORTH,Mary Anna BOGLE,Liyuan LIANG,Eric PIERCE

《环境科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 596-604 doi: 10.1007/s11783-014-0709-2

摘要: Development and demonstration of reliable measurement techniques that can detect and help quantify the nature and extent of elemental mercury (Hg(0)) in the subsurface are needed to reduce uncertainties in the decision-making process and increase the effectiveness of remedial actions. We conducted field tests at the Y-12 National Security Complex in Oak Ridge, Tennessee, USA, to determine if sampling and analysis of Hg(0) vapors in the shallow subsurface (<0.3 m depth) can be used to as an indicator of the location and extent of Hg(0) releases in the subsurface. We constructed a rigid polyvinyl chloride push probe assembly, which was driven into the ground. Soil gas samples were collected through a sealed inner tube of the assembly and were analyzed immediately in the field with a Lumex and/or Jerome Hg(0) analyzer. Time-series sampling showed that Hg vapor concentrations were fairly stable over time, suggesting that the vapor phase Hg(0) was not being depleted and that sampling results were not sensitive to the soil gas purge volume. Hg(0) vapor data collected at over 200 push probe locations at 3 different release sites correlated very well to areas of known Hg(0) contamination. Vertical profiling of Hg(0) vapor concentrations conducted at two locations provided information on the vertical distribution of Hg(0) contamination in the subsurface. We conclude from our studies that soil gas sampling and analysis can be conducted rapidly and inexpensively at large scales to help identify areas contaminated with Hg(0).

关键词: push probe     spill     characterization     mapping     gas    

Development of source profiles and their application in source apportionment of PM

Ningning Zhang, Mazhan Zhuang, Jie Tian, Pengshan Tian, Jieru Zhang, Qiyuan Wang, Yaqing Zhou, Rujin Huang, Chongshu Zhu, Xuemin Zhang, Junji Cao

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0879-1

摘要: Seasonal and spatial distribution of PM and its component were shown. Local source profiles of major PM sources were developed. Source apportionment was conducted using CMB model. Inorganic secondary components is the biggest contribution at Xiamen. Ambient PM samples were collected at four sites in Xiamen, including Gulangyu (GLY), Hongwen (HW), Huli (HL) and Jimei (JM) during January, April, July and October 2013. Local source samples were obtained from coal burning power plants, industries, motor vehicles, biomass burning, fugitive dust, and sea salt for the source apportionment studies. The highest value of PM mass concentration and species related to human activities (SO , NO , Pb, Ni, V, Cu, Cd, organic carbon (OC) and elemental carbon (EC)) were found in the ambient samples from HL, and the highest and lowest loadings of PM and its components occurred in winter and summer, respectively. The reconstructed mass balance indicated that ambient PM consisted of 24% OM (organic matter), 23% sulfate, 14% nitrate, 9% ammonium, 9% geological material, 6% sea salt, 5% EC and 10% others. For the source profiles, the dominant components were OC for coal burning, motor vehicle, biomass burning and sea salt; SO for industry; and crustal elements for fugitive dust. Source contributions were calculated using a chemical mass balance (CMB) model based on ambient PM concentrations and the source profiles. GLY was characterized by high contributions from secondary sulfate and cooking, while HL and JM were most strongly affected by motor vehicle emissions, and biomass burning and fugitive dust, respectively. The CMB results indicated that PM from Xiamen is composed of 27.4% secondary inorganic components, 20.8% motor vehicle emissions, 11.7% fugitive dust, 9.9% sea salt, 9.3% coal burning, 5.0% biomass burning, 3.1% industry and 6.8% others.

关键词: PM2.5     Source profile     Source apportionment     CMB     Xiamen    

δN-stable isotope analysis of NH: An overview on analytical measurements, source sampling and its source

《环境科学与工程前沿(英文)》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1414-6

摘要:

• Challenges in sampling of NH3 sources for d15N analysis are highlighted.

关键词: Aerosol ammonium     Atmospheric gaseous ammonia     Isotope fingerprinting     Isotope-based source apportionment     Ammonia gas-to-particle conversion    

Fault tolerant control strategy for modular PWM current source inverter

《能源前沿(英文)》 2023年 第17卷 第2期   页码 228-238 doi: 10.1007/s11708-022-0852-6

摘要: In this paper, a fault-tolerant control method for an input-series output-parallel modular grid-tied pulse-width modulation (PWM) current source inverter is proposed to address the most commonly seen single symmetrical gate-commutated thyristor (SGCT) open-circuit fault problems. This method actively offsets the neutral point of the current space vector to ensure a sinusoidal output of the grid current, and it can achieve the upper limit power of the inverter under the condition of a single SGCT open-circuit fault. In addition, an active damping control method based on grid harmonic current feedback is proposed after analyzing the influence of the transformer ferromagnetic resonance caused by the neutral point offset on the power quality of the grid current. It has been demonstrated that the proposed method effectively suppresses the resonance caused by the transformer and the modified modulation, improving the grid current’s power quality.

关键词: current source converter (CSC)     fault-tolerant control     space vector modulation     active damping     resonance suppression     power quality    

Variational mode decomposition based modal parameter identification in civil engineering

Mingjie ZHANG, Fuyou XU

《结构与土木工程前沿(英文)》 2019年 第13卷 第5期   页码 1082-1094 doi: 10.1007/s11709-019-0537-3

摘要: An out-put only modal parameter identification method based on variational mode decomposition (VMD) is developed for civil structure identifications. The recently developed VMD technique is utilized to decompose the free decay response (FDR) of a structure into to modal responses. A novel procedure is developed to calculate the instantaneous modal frequencies and instantaneous modal damping ratios. The proposed identification method can straightforwardly extract the mode shape vectors using the modal responses extracted from the FDRs at all available sensors on the structure. A series of numerical and experimental case studies are conducted to demonstrate the efficiency and highlight the superiority of the proposed method in modal parameter identification using both free vibration and ambient vibration data. The results of the present method are compared with those of the empirical mode decomposition-based method, and the superiorities of the present method are verified. The proposed method is proved to be efficient and accurate in modal parameter identification for both linear and nonlinear civil structures, including structures with closely spaced modes, sudden modal parameter variation, and amplitude-dependent modal parameters, etc.

关键词: modal parameter identification     variational mode decomposition     civil structure     nonlinear system     closely spaced modes    

Non-convex sparse optimization-based impact force identification with limited vibration measurements

《机械工程前沿(英文)》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0762-2

摘要: Impact force identification is important for structure health monitoring especially in applications involving composite structures. Different from the traditional direct measurement method, the impact force identification technique is more cost effective and feasible because it only requires a few sensors to capture the system response and infer the information about the applied forces. This technique enables the acquisition of impact locations and time histories of forces, aiding in the rapid assessment of potentially damaged areas and the extent of the damage. As a typical inverse problem, impact force reconstruction and localization is a challenging task, which has led to the development of numerous methods aimed at obtaining stable solutions. The classical 2 regularization method often struggles to generate sparse solutions. When solving the under-determined problem, 2 regularization often identifies false forces in non-loaded regions, interfering with the accurate identification of the true impact locations. The popular 1 sparse regularization, while promoting sparsity, underestimates the amplitude of impact forces, resulting in biased estimations. To alleviate such limitations, a novel non-convex sparse regularization method that uses the non-convex 12 penalty, which is the difference of the 1 and 2 norms, as a regularizer, is proposed in this paper. The principle of alternating direction method of multipliers (ADMM) is introduced to tackle the non-convex model by facilitating the decomposition of the complex original problem into easily solvable subproblems. The proposed method named 12-ADMM is applied to solve the impact force identification problem with unknown force locations, which can realize simultaneous impact localization and time history reconstruction with an under-determined, sparse sensor configuration. Simulations and experiments are performed on a composite plate to verify the identification accuracy and robustness with respect to the noise of the 12-ADMM method. Results indicate that compared with other existing regularization methods, the 12-ADMM method can simultaneously reconstruct and localize impact forces more accurately, facilitating sparser solutions, and yielding more accurate results.

关键词: impact force identification     inverse problem     sparse regularization     under-determined condition     alternating direction method of multipliers    

The research on structural damage identification using rough set and integrated neural network

Juelong LI, Hairui LI, Jianchun XING, Qiliang YANG

《机械工程前沿(英文)》 2013年 第8卷 第3期   页码 305-310 doi: 10.1007/s11465-013-0259-5

摘要:

A huge amount of information and identification accuracy in large civil engineering structural damage identification has not been addressed yet. To efficiently solve this problem, a new damage identification method based on rough set and integrated neural network is first proposed. In brief, rough set was used to reduce attributes so as to decrease spatial dimensions of data and extract effective features. And then the reduced attributes will be put into the sub-neural network. The sub-neural network can give the preliminary diagnosis from different aspects of damage. The decision fusion network will give the final damage identification results. The identification examples show that this method can simplify the redundant information to reduce the neural network model, making full use of the range of information to effectively improve the accuracy of structural damage identification.

关键词: rough set     integrated neural network     damage identification     decision making fusion    

DITCHES AND PONDS CAN BE THE SOURCES OR SINKS OF NON-POINT SOURCE POLLUTION: OBSERVATIONS IN AN UPLAND

《农业科学与工程前沿(英文)》 2023年 第10卷 第4期   页码 607-626 doi: 10.15302/J-FASE-2023517

摘要:

As the common features of agroecosystems, ditches and ponds benefit the irrigation and drainage, as well as intercepting non-point source pollutants. However, most ditch-pond studies have been conducted in lowland areas. To test this source-sink assumption in upland areas, this study made observations on the ecological function of the ditch and pond system in a typical catchment in China. First, the changes in ponds in the catchment were analyzed using high-resolution remote sensing data. Then, the migration of agricultural pollutants in ditches and ponds were analyzed by field sampling and laboratory detection. The results showed that over the past 15 years the length of ditches in the catchment and the number of small ponds (< 500 m2) have increased by 32% and 75%, respectively. The rate of change in nutrient concentrations in the ditches and ponds were mostly from −20% to 20%, indicating ditches and ponds can be both sources and sinks for agricultural pollutants. Lastly, the contributing factors were explored and it was found that ditches and ponds are important sinks in dry season. However, during the rainy season, ditches and ponds become sources of pollutants, with the rapid drainage of ditches and the overflow of ponds in upland areas. The results of this study revealed that the ditches and ponds could be used for ecological engineering in upland catchments to balance drainage and intercept pollutants.

关键词: ditches     ponds     non-point source pollution     mountainous areas     nitrogen     phosphorus    

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

《农业科学与工程前沿(英文)》 2023年 第10卷 第4期   页码 503-509 doi: 10.15302/J-FASE-2023528

摘要:

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

关键词: GREEN     AGRICULTURAL     PROMOTE     POLLUTION     SOURCE     DEVELOPMENT     POINT     STRENGTHENING     CONTROL    

Mechanical design, modeling, and identification for a novel antagonistic variable stiffness dexterous

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0691-5

摘要: This study traces the development of dexterous hand research and proposes a novel antagonistic variable stiffness dexterous finger mechanism to improve the safety of dexterous hand in unpredictable environments, such as unstructured or man-made operational errors through comprehensive consideration of cost, accuracy, manufacturing, and application. Based on the concept of mechanical passive compliance, which is widely implemented in robots for interactions, a finger is dedicated to improving mechanical robustness. The finger mechanism not only achieves passive compliance against physical impacts, but also implements the variable stiffness actuator principle in a compact finger without adding supererogatory actuators. It achieves finger stiffness adjustability according to the biologically inspired stiffness variation principle of discarding some mobilities to adjust stiffness. The mechanical design of the finger and its stiffness adjusting methods are elaborated. The stiffness characteristics of the finger joint and the actuation unit are analyzed. Experimental results of the finger joint stiffness identification and finger impact tests under different finger stiffness presets are provided to verify the validity of the model. Fingers have been experimentally proven to be robust against physical impacts. Moreover, the experimental part verifies that fingers have good power, grasping, and manipulation performance.

关键词: multifingered hand     mechanism design     robot safety     variable stiffness actuator    

Performance analysis of an air-source heat pump using an immersed water condenser

Jie JI, Huide FU, Hanfeng HE, Gang PEI,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 234-245 doi: 10.1007/s11708-009-0056-3

摘要: A distributed model of an air-source heat pump (ASHP) system and its experimental setup using an immersed water condenser were presented. Dynamic performance of the ASHP was then evaluated by both simulation and experiment. The results indicated that the system coefficient of performance (COP) decreased as the condenser temperature increased, ranging from 4.41 to 2.32 with the average COP equaling 3.29 during the experiment. Comparisons between simulation results and experimental measurements demonstrated that the model was able to yield satisfactory predictions. Furthermore, temperature profiles of the refrigerant in the evaporator and condenser were also given. This paper provides the theoretical and experimental background for ASHP system optimization and a valuable reference for a solar air-source heat pump water heater when the solar irradiation energy is insufficient on cloudy or rainy days.

关键词: air-source     heat pump     distributed model     immersed water condenser    

标题 作者 时间 类型 操作

The source and transport of bioaerosols in the air: A review

期刊论文

Identification and ranking of the risky organic contaminants in the source water of the Danjiangkou reservoir

Qingwei BU, Donghong WANG, Zijian WANG, Junnong GU

期刊论文

Nitrogen pollution and source identification of urban ecosystem surface water in Beijing

Yufen REN, Zhiwei XU, Xinyu ZHANG, Xiaoke WANG, Xiaomin SUN, D. J. BALLANTINE, Shengzhong WANG

期刊论文

Inverse uncertainty characteristics of pollution source identification for river chemical spill incidents

Jiping Jiang, Feng Han, Yi Zheng, Nannan Wang, Yixing Yuan

期刊论文

Mercury source zone identification using soil vapor sampling and analysis

David WATSON,Carrie MILLER,Brian LESTER,Kenneth LOWE,George SOUTHWORTH,Mary Anna BOGLE,Liyuan LIANG,Eric PIERCE

期刊论文

Development of source profiles and their application in source apportionment of PM

Ningning Zhang, Mazhan Zhuang, Jie Tian, Pengshan Tian, Jieru Zhang, Qiyuan Wang, Yaqing Zhou, Rujin Huang, Chongshu Zhu, Xuemin Zhang, Junji Cao

期刊论文

δN-stable isotope analysis of NH: An overview on analytical measurements, source sampling and its source

期刊论文

Fault tolerant control strategy for modular PWM current source inverter

期刊论文

Variational mode decomposition based modal parameter identification in civil engineering

Mingjie ZHANG, Fuyou XU

期刊论文

Non-convex sparse optimization-based impact force identification with limited vibration measurements

期刊论文

The research on structural damage identification using rough set and integrated neural network

Juelong LI, Hairui LI, Jianchun XING, Qiliang YANG

期刊论文

DITCHES AND PONDS CAN BE THE SOURCES OR SINKS OF NON-POINT SOURCE POLLUTION: OBSERVATIONS IN AN UPLAND

期刊论文

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

期刊论文

Mechanical design, modeling, and identification for a novel antagonistic variable stiffness dexterous

期刊论文

Performance analysis of an air-source heat pump using an immersed water condenser

Jie JI, Huide FU, Hanfeng HE, Gang PEI,

期刊论文