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Improved nitrogen removal in dual-contaminated surface water by photocatalysis

Yongming ZHANG, Rong YAN, Zhen ZOU, Jiewei WANG, Bruce E. RITTMANN

《环境科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 428-436 doi: 10.1007/s11783-012-0401-3

摘要: River waters in China have dual contamination by nutrients and recalcitrant organic compounds. In principle, the organic compounds could be used to drive denitrification of nitrate, thus arresting eutrophication potential, if the recalcitrant organics could be made bioavailable. This study investigated the potential to make the recalcitrant organics bioavailable through photocatalysis. Batch denitrification tests in a biofilm reactor demonstrated that dual-contaminated river water was short of available electron donor, which resulted in low total nitrogen (TN) removal by denitrification. However, the denitrification rate was increased significantly by adding glucose or by making the organic matters of the river water more bioavailable through photocatalysis. Photocatalysis for 15 min increased the Chemical Oxygen Demand (COD) of the river water from 53 to 84 mg·L and led to a 4-fold increase in TN removal. The increase in TN removal gave the same effect as adding 92 mg·L of glucose. During the photocatalysis experiments, the COD increased because photocatalysis transformed organic molecules from those that are resistant to dichromate oxidation in the COD test to those that can be oxidized by dichromate. This phenomenon was verified by testing photocatalysis of pyridine added to the river water. These findings point to the potential for N removal via denitrification after photocatalysis, and they also suggest that the rivers in China may be far more polluted than indicated by COD assays.

关键词: dual contamination     eutrophication     photocatalysis     remediation     surface water    

Spatial prediction of soil contamination based on machine learning: a review

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1693-1

摘要:

● A review of machine learning (ML) for spatial prediction of soil contamination.

关键词: Soil contamination     Machine learning     Prediction     Spatial distribution    

Strategies to manage the risk of heavy metal(loid) contamination in agricultural soils

Fang-Jie ZHAO

《农业科学与工程前沿(英文)》 2020年 第7卷 第3期   页码 333-338 doi: 10.15302/J-FASE-2020335

摘要:

Soil contamination with heavy metal(loid)s threatens soil ecological functions, water quality and food safety; the latter is the focus of this review. Cadmium (Cd) and arsenic (As) are the toxic elements of most concern for food safety because they are relatively easily taken up by food crops. Rice is a major contributor of both Cd and As intakes to the Chinese population. Contamination and soil acidification are the main causes of high Cd levels in rice grains produced in some areas of southern China. The risk of Cd and As accumulation in food crops can be mitigated through agronomic practices and crop breeding. Liming is effective and economical at reducing Cd uptake by rice in acid soils. Paddy water management can produce opposite effects on Cd and As accumulation. Many genes controlling Cd and As uptake and translocation have been characterized, paving the way to breeding low accumulating crop cultivars through marker-assisted molecular breeding or genetic engineering. It is important to protect agricultural soils from future contamination. Long-term monitoring of anthropogenic additions and accumulation of heavy metal(loid)s in agricultural soils should be undertaken. Mass-balance models should be constructed to evaluate future trends of metal(loid)s in agricultural soils at a regional scale.

关键词: arsenic     cadmium     food safety     heavy metals     soil contamination    

Nitrobenzene contamination of groundwater in a petrochemical industry site

Yongsheng Zhao, Lin Lin, Mei Hong

《环境科学与工程前沿(英文)》 2019年 第13卷 第2期 doi: 10.1007/s11783-019-1107-6

摘要:

The contaminant transport distance is predicted using numerical model.

Zero-valent iron can be used to effectively transform nitrobenzene to aniline.

Experiment shows that two-layer PRB systems have a very good treatment effect.

关键词: Nitrobenzene     Benzene     Groundwater     Zero-valent iron     Permeable reactive barrier    

Evaluating heavy metal contamination of riverine sediment cores in different land-use areas

Wenzhong Tang, Liu Sun, Limin Shu, Chuang Wang

《环境科学与工程前沿(英文)》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1283-4

摘要: Abstract • Metal pollution was studied in riverine sediments from different land-use areas. • Cd was the most serious heavy metal contaminant in riverine sediment cores. • Riverine sediment cores from industrial area were most polluted by heavy metals. • B1 fraction determined metal pollution, risk and toxicity in riverine sediments. Anthropogenic activities are regarded as the main sources of heavy metal pollution, yet few studies have investigated the effects of land-use setting on heavy metal accumulation in riverine sediments. Based on both total contents and geochemical fractions, heavy metal pollution, risk and toxicity were determined in riverine sediment cores from different land-use areas (mountain area- MA, farm area- FA, city area- CA, and industrial area- IA) of the Yang River Basin in North China. The results showed that FA had higher contents of riverine sedimentary Cu; CA had higher contents of Cd; IA had higher contents of both Cd and Zn. Most riverine sediments from FA and IA were contaminated with the investigated metals, although these concentrations were evaluated to have low potential ecological risk and no toxicity to benthic organisms. However, a high proportion of Cd in the B1 fraction of riverine sediments in IA indicating high risk should receive more attention. The B1 fraction largely determined the contamination, risk and toxicity levels associated with heavy metals in the riverine sediments of the Yang River Basin.

关键词: Heavy metals     Riverine sediments     Pollution     Land-use    

E-waste environmental contamination and harm to public health in China

null

《医学前沿(英文)》 2015年 第9卷 第2期   页码 220-228 doi: 10.1007/s11684-015-0391-1

摘要:

The adverse effects of electronic waste (e-waste) on the human body have stirred up concern in recent years. China is one of the countries that confront serious pollution and human exposure of e-waste, and the majority of the population is exposed to potentially hazardous substances that are derived from informal e-waste recycling processes. This study reviews recent reports on human exposure to e-waste in China, with particular focus on exposure routes (e.g., inhalation and ingestion) and several toxicities of human (e.g., endocrine system, respiratory system, reproductive system, developmental toxicity, neurotoxicity, and genetic toxicity). Pieces of evidence that associate e-waste exposure with human health effects in China are assessed. The role of toxic heavy metals (e.g., lead, cadmium, chromium, mercury, and nickel) and organic pollutants (e.g., polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyl (PCBs), polycyclic aromatic hydrocarbons (PAHs), polybrominated biphenyls (PBBs), polyhalogenated aromatic hydrocarbons (PHAHs), bisphenol A (BPA)) on human health is also briefly discussed.

关键词: e-waste     heavy metal     organic pollutant     hazardous     toxicity     human health     China    

Hazard and vulnerability evaluation of water distribution system in cases of contamination intrusion

Kunlun XIN, Tao TAO, Yong WANG, Suiqing LIU

《环境科学与工程前沿(英文)》 2012年 第6卷 第6期   页码 839-848 doi: 10.1007/s11783-012-0409-8

摘要: In this paper, it proposed an index system for hazard and vulnerability evaluations of water distribution networks, based on the simulation of contamination events caused by pollutant injections at different junctions. It attempted to answer the following two questions in the case of contamination events: 1) Which are the most hazardous junctions? 2) Which are the most vulnerable junctions? With EPANET toolkit, it simulated the propagation of the contaminant, and calculated the peak concentration of the contaminant and mass delivered at different nodes. According to types of consumers, different weights were assigned to the consumer nodes for assessing the influence of the contaminant on the consumers. Using the method proposed herein, both the hazard index and vulnerability index were calculated for each node in the pipe network. The presented method was therefore applied to the water network of the city of Zhenjiang, which contains two water plants, two booster pump stations with storage tanks. In conclusion, the response time, the relationships between the peak concentration of contaminant and the total absorption are the most important factors in hazard and vulnerability evaluation of the water distribution network.

关键词: water distribution network     hazard     vulnerability     contaminant accident    

A novel task-oriented framework for dual-arm robotic assembly task

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 528-545 doi: 10.1007/s11465-021-0638-2

摘要: In industrial manufacturing, the deployment of dual-arm robots in assembly tasks has become a trend. However, making the dual-arm robots more intelligent in such applications is still an open, challenging issue. This paper proposes a novel framework that combines task-oriented motion planning with visual perception to facilitate robot deployment from perception to execution and finish assembly problems by using dual-arm robots. In this framework, visual perception is first employed to track the effects of the robot behaviors and observe states of the workpieces, where the performance of tasks can be abstracted as a high-level state for intelligent reasoning. The assembly task and manipulation sequences can be obtained by analyzing and reasoning the state transition trajectory of the environment as well as the workpieces. Next, the corresponding assembly manipulation can be generated and parameterized according to the differences between adjacent states by combining with the prebuilt knowledge of the scenarios. Experiments are set up with a dual-arm robotic system (ABB YuMi and an RGB-D camera) to validate the proposed framework. Experimental results demonstrate the effectiveness of the proposed framework and the promising value of its practical application.

关键词: dual-arm assembly     AI reasoning     intelligent system     task-oriented motion planning     visual perception    

Strain and process engineering toward continuous industrial fermentation

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1336-1353 doi: 10.1007/s11705-022-2284-6

摘要: Most current biotechnology industries are based on batch or fed-batch fermentation processes, which often show low productivity and high production costs compared to chemical processes. To increase the economic competitiveness of biological processes, continuous fermentation technologies are being developed that offer significant advantages in comparison with batch/fed-batch fermentation processes, including: (1) removal of potential substrates and product inhibition, (2) prolonging the microbial exponential growth phase and enhancing productivity, and (3) avoiding repeated fermentation preparation and lowering operation and installation costs. However, several key challenges should be addressed for the industrial application of continuous fermentation processes, including (1) contamination of the fermentation system, (2) degeneration of strains, and (3) relatively low product titer. In this study, we reviewed and discussed metabolic engineering and synthetic biology strategies to address these issues.

关键词: continuous fermentation     productivity     contamination     strain degeneration     metabolic engineering    

Analysis and assessment of heavy metal contamination in surface water and sediments: a case study from

Zhaoming WANG,Ranhao SUN,Haiping ZHANG,Liding CHEN

《环境科学与工程前沿(英文)》 2015年 第9卷 第2期   页码 240-249 doi: 10.1007/s11783-014-0646-0

摘要: Concentrations of the heavy metals Cu, Ni, Pb, Zn, Cd, and Cr were examined in surface water and sediment from the Luan River inChina,. With a decline in Cu and Ni concentration found in surface water at downstream stations. This finding suggests that water currents are a major explanatory factor in heavy metal contamination. The abundance of Cr, Pb, and Cd observed in the middle reaches of the river indicates heavy metal contamination in local areas, although there was an obvious decrease in concentrations in the water downstream of the Daheiting Reservoir. The significant rising trend in Cu, Pb, and Ni seen the sediment farther away from the river also suggests that anthropogenic activities contribute to heavy metal pollution Sediments were therefore used as environmental indicators, with sediment assessment was conducted using the geo-accumulation index ( ) and the potential ecological risk index ( ). The values revealed that Cd (3.13) and Cr (2.39) had accumulated significantly in the Luan River. The values for most (89%) of the sampling stations were higher than 300, suggesting that sediment from the Luan River poses a severe ecological risk, with the potential ecological risks downstream higher than that in the upper and middle streams. Good correlations among Pb/Ni, Pb/Cd, Cu/Pb, and Cu/Cd in the water and Cr/Ni in the sediment were observed. Cluster analysis suggested that Cd may have various origins, being derived from anthropogenic sources.

关键词: heavy metal     water     sediment     geo-accumulation index     Luan River    

Comprehensive evaluation of heavy metal contamination of sediment in Lake Dianchi by using modified AHP

ZHANG Yan, GAO Xiang, ZHONG Zhenyu, PENG Buzhuo, DENG Xihai

《环境科学与工程前沿(英文)》 2008年 第2卷 第3期   页码 370-379 doi: 10.1007/s11783-008-0054-4

摘要: Through the use of general sampling and measurement by Cs dating, problems regarding the absence of monitoring data can easily be resolved. Further, weighted values need to be determined while Environment Quality Comprehensive Index (EQCI) is commonly used as applied in environmental quality comprehensive evaluation. In order to overcome the subjectivity in determining weights, the modified Analytical Hierarchy Process (AHP) method was designed. The modified AHP method involved the following key procedures: First, the parameters and were calculated based on the monitoring data; second, the factors were put in order according to the symbol and value of and ; third, the continuous odd integers, which represented the importance of factors, were given to factors according to their seating order; and, fourth, the factor weights were determined from the pair-wise comparison matrix calculated by the ratio of the given odd integers. Therefore, the weights were completely based on the monitoring data. In the present study, the comprehensive quality of sediments in five sections of Lake Dianchi were evaluated and the results indicated that the current contamination of sediments in each lake section is much more serious than at any other time in history.

关键词: Dianchi     Analytical Hierarchy     monitoring     modified Analytical     importance    

Development of a dual temperature control system for isoprene biosynthesis in

《化学科学与工程前沿(英文)》 2022年 第16卷 第7期   页码 1079-1089 doi: 10.1007/s11705-021-2088-0

摘要: Conflict between cell growth and product accumulation is frequently encountered in the biosynthesis of secondary metabolites. To address the growth-production conflict in yeast strains harboring the isoprene synthetic pathway in the mitochondria, the dynamic control of isoprene biosynthesis was explored. A dual temperature regulation system was developed through engineering and expression regulation of the transcriptional activator Gal4p. A cold-sensitive mutant, Gal4ep19, was created by directed evolution of Gal4p based on an internally developed growth-based high-throughput screening method and expressed under the heat-shock promoter PSSA4 to control the expression of PGAL-driven pathway genes in the mitochondria. Compared to the control strain with constitutively expressed wild-type Gal4p, the dual temperature regulation strategy led to 34.5% and 72% improvements in cell growth and isoprene production, respectively. This study reports the creation of the first cold-sensitive variants of Gal4p by directed evolution and provides a dual temperature control system for yeast engineering that may also be conducive to the biosynthesis of other high-value natural products.

关键词: transcriptional activator     directed evolution     dynamic control     heat-shock     isoprene    

基于双CPU结构的数据监控系统设计

贾贵玺,齐乐

《中国工程科学》 2006年 第8卷 第4期   页码 68-71

摘要:

针对通信系统中,对所有客户线路的电压、电流、温度等数据进行实时多路采集监控,提出了一种基于双CPU结构的数据监控系统的设计方法以及硬件组成。讨论了系统主要芯片之间的连线方法以及软件流程。该系统已经成功应用在邮电系统48V通信线路监控。实践证明,双CPU设计方案不仅满足了系统高运算量、高实时性、抗干扰性要求,而且优化了软硬件设计。

关键词: 数据监控     双CPU     双口RAM    

Experimental study of stratified lean burn characteristics on a dual injection gasoline engine

Chun XIA, Tingyu ZHAO, Junhua FANG, Lei ZHU, Zhen HUANG

《能源前沿(英文)》 2022年 第16卷 第6期   页码 900-915 doi: 10.1007/s11708-021-0812-6

摘要: Due to increasingly stringent fuel consumption and emission regulation, improving thermal efficiency and reducing particulate matter emissions are two main issues for next generation gasoline engine. Lean burn mode could greatly reduce pumping loss and decrease the fuel consumption of gasoline engines, although the burning rate is decreased by higher diluted intake air. In this study, dual injection stratified combustion mode is used to accelerate the burning rate of lean burn by increasing the fuel concentration near the spark plug. The effects of engine control parameters such as the excess air coefficient (Lambda), direct injection (DI) ratio, spark interval with DI, and DI timing on combustion, fuel consumption, gaseous emissions, and particulate emissions of a dual injection gasoline engine are studied. It is shown that the lean burn limit can be extended to Lambda= 1.8 with a low compression ratio of 10, while the fuel consumption can be obviously improved at Lambda= 1.4. There exists a spark window for dual injection stratified lean burn mode, in which the spark timing has a weak effect on combustion. With optimization of the control parameters, the brake specific fuel consumption (BSFC) decreases 9.05% more than that of original stoichiometric combustion with DI as 2 bar brake mean effective pressure (BMEP) at a 2000 r/min engine speed. The NOx emissions before three-way catalyst (TWC) are 71.31% lower than that of the original engine while the particle number (PN) is 81.45% lower than the original engine. The dual injection stratified lean burn has a wide range of applications which can effectively reduce fuel consumption and particulate emissions. The BSFC reduction rate is higher than 5% and the PN reduction rate is more than 50% with the speed lower than 2400 r/min and the load lower than 5 bar.

关键词: dual injection     stratified lean burn     gasoline engine     particulate matter emission     combustion analysis    

Optimization of the power, efficiency and ecological function for an air-standard irreversible Dual-Miller

Zhixiang WU, Lingen CHEN, Yanlin GE, Fengrui SUN

《能源前沿(英文)》 2019年 第13卷 第3期   页码 579-589 doi: 10.1007/s11708-018-0557-z

摘要: This paper establishes an irreversible Dual-Miller cycle (DMC) model with the heat transfer (HT) loss, friction loss (FL) and other internal irreversible losses. To analyze the effects of the cut-off ratio ( ) and Miller cycle ratio ( ) on the power output ( ), thermal efficiency ( ) and ecological function ( ), obtain the optimal and optimal , and compare the performance characteristics of DMC with its simplified cycles and with different optimization objective functions, the , and of irreversible DMC are analyzed and optimized by applying the finite time thermodynamic (FTT) theory. Expressions of , and are derived. The relationships among , , and compression ratio ( ) are obtained by numerical examples. The effects of and on , , , maximum power output ( ), maximum efficiency ( ) and maximum ecological function ( ) are analyzed. Performance differences among the DMC, the Otto cycle (OC), the Dual cycle (DDC), and the Otto-Miller cycle (OMC) are compared for fixed design parameters. Performance characteristics of irreversible DMC with the choice of , and as optimization objective functions are analyzed and compared. The results show that the irreversible DMC engine can reach a twice-maximum power, a twice-maximum efficiency, and a twice-maximum ecological function, respectively. Moreover, when choosing as the optimization objective, there is a 5.2% of improvement in while there is a drop of only 2.7% in compared to choosing as the optimization objective. However, there is a 5.6% of improvement in while there is a drop of only 1.3% in compared to choosing as the optimization objective.

关键词: finite-time thermodynamics     Dual-Miller cycle     power output     thermal efficiency     ecological function    

标题 作者 时间 类型 操作

Improved nitrogen removal in dual-contaminated surface water by photocatalysis

Yongming ZHANG, Rong YAN, Zhen ZOU, Jiewei WANG, Bruce E. RITTMANN

期刊论文

Spatial prediction of soil contamination based on machine learning: a review

期刊论文

Strategies to manage the risk of heavy metal(loid) contamination in agricultural soils

Fang-Jie ZHAO

期刊论文

Nitrobenzene contamination of groundwater in a petrochemical industry site

Yongsheng Zhao, Lin Lin, Mei Hong

期刊论文

Evaluating heavy metal contamination of riverine sediment cores in different land-use areas

Wenzhong Tang, Liu Sun, Limin Shu, Chuang Wang

期刊论文

E-waste environmental contamination and harm to public health in China

null

期刊论文

Hazard and vulnerability evaluation of water distribution system in cases of contamination intrusion

Kunlun XIN, Tao TAO, Yong WANG, Suiqing LIU

期刊论文

A novel task-oriented framework for dual-arm robotic assembly task

期刊论文

Strain and process engineering toward continuous industrial fermentation

期刊论文

Analysis and assessment of heavy metal contamination in surface water and sediments: a case study from

Zhaoming WANG,Ranhao SUN,Haiping ZHANG,Liding CHEN

期刊论文

Comprehensive evaluation of heavy metal contamination of sediment in Lake Dianchi by using modified AHP

ZHANG Yan, GAO Xiang, ZHONG Zhenyu, PENG Buzhuo, DENG Xihai

期刊论文

Development of a dual temperature control system for isoprene biosynthesis in

期刊论文

基于双CPU结构的数据监控系统设计

贾贵玺,齐乐

期刊论文

Experimental study of stratified lean burn characteristics on a dual injection gasoline engine

Chun XIA, Tingyu ZHAO, Junhua FANG, Lei ZHU, Zhen HUANG

期刊论文

Optimization of the power, efficiency and ecological function for an air-standard irreversible Dual-Miller

Zhixiang WU, Lingen CHEN, Yanlin GE, Fengrui SUN

期刊论文