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Abundance, spatial distribution, and physical characteristics of microplastics in stormwater detention

《环境科学与工程前沿（英文）》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1724-y

摘要： Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms driving the substantial transport of MP across different environmental compartments. Storm events can transport MP beyond boundaries, such as from the land to groundwater or the ocean, as has already been discovered for organic carbon transport. Urban stormwater detention ponds are suitable environments to study the impact of stormwater on the environmental fate and transport of MP. Herein, we investigate the longitudinal and vertical distribution of MP within two detention ponds with different physical characteristics. Soil samples were collected at various locations and from multiple depths (surface and subsurface layers) for measuring MP concentrations using fluorescence microscopy. Our findings show that MP are retained more near the inlet of the ponds, and MP of larger sizes were found more abundantly near inlets than outlets. We also found that MP mass and sizes decrease from surface soil to subsurface soil. In the pond, where vegetation (grass root network) was more considerable, MP were found more evenly distributed along the depth. In terms of shape, the fragments were the most abundant MP shape.

关键词： Microplastic     Environmental transport     Soil pollution     Stormwater     Detention ponds    

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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    

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Design and characteristics of electric supercharger for diesel engine acceleration by additional rapid

YAO Chun-de, ZHOU Hong-xiu

《机械工程前沿（英文）》 2006年 第1卷 第4期   页码 409-412 doi: 10.1007/s11465-006-0048-5

摘要： The ES (electric supercharger) driven by a high-speed brushless motor was developed to solve the problem of smoke caused by the turbocharger s sluggish response during acceleration. Its rotation speed was from 6 000 r/min to 24 000 r/min, and the maximum flux was 0.1 kg/s. The structural design of the electric supercharger is novel, which makes it easier to set the lubricating installation and to assemble. The velocity distribution at the outlet of the electric supercharger is determined by hot-wire anemometry under various rotation speeds in steady state. Furthermore, the trends of the flux and charge rate with various speeds were analyzed. In addition, the transient response was detected from the motor setup to smooth running within 10 s, 15 s, 20 s and 25 s respectively, and the characteristic of the transient flux is under pilot study. Research results indicate that the electric supercharger can respond rapidly with the great flux, and it is independent of the operating conditions of a diesel engine. Therefore, it is a feasible way to reduce smoke emission and improve the acceleration performance.

关键词： acceleration     velocity distribution     high-speed brushless     turbocharger     electric supercharger    

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Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿（英文）》 2008年 第3卷 第1期   页码 28-36 doi: 10.1007/s11465-008-0007-4

摘要： This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.

关键词： numerical solution     temperature corresponding     temperature distribution     end-most     ball-screw    

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CFD Simulation of thermal hydraulic characteristics in a typical upper plenum of RPV

Mingjun WANG, Lianfa WANG, Yingjie WANG, Wenxi TIAN, Jian DENG, Guanghui SU, Suizheng QIU

《能源前沿（英文）》 2021年 第15卷 第4期   页码 930-945 doi: 10.1007/s11708-021-0728-1

摘要： A comparative computational fluid dynamics (CFD) study was conducted on the three different types of pressurized water reactor (PWR) upper plenum, named TYPE 1 (support columns (SCs) and control rod guide tubes (CRGTs) with two large windows), TYPE 2 (SCs and CRGTs without windows), and TYPE 3 (two parallel perforated barrel shells and CRGTs). First, three types of upper plenum geometry information were collected, simplified, and adopted into the BORA facility, which is a 1/5 scale system of the four-loop PWR reactor. Then, the geometry, including the upper half core, upper plenum region, and hot legs, was built using the platform. After that, an unsteady calculation to simulate the reactor balance operation at hot full power scenario was performed. Finally, the differences of flowrate distribution at the core outlet and temperature distribution and transverse velocity inside the hot legs with different upper plenum internals were compared. The results suggest that TYPE 1 upper plenum internals cause the largest flowrate difference at the core outlet while TYPE 3 leads to the most even distributed flowrate. The distribution and evolution pattern of the tangential velocity inside hot legs is highly dependent on the upper plenum internals. Two counter-rotating swirls exist inside the TYPE 1 hot leg and only one swirl revolving around the hog leg axis exist inside the TYPE 2 hot leg. For TYPE 3, two swirls like that of TYPE 1 rotating around the hot leg axis significantly increase the temperature homogenization speed. This research provides meaningful guidelines for the future optimization and design of advanced PWR upper plenum internal structures.

关键词： pressurized water reactor (PWR)     upper plenum     internal structures     temperature distribution     computational fluid dynamics (CFD)    

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中美页岩气成藏条件、分布特征差异研究与启示

李建忠,李登华,董大忠,王社教

《中国工程科学》 2012年 第14卷 第6期   页码 56-63

摘要：

美国页岩气大多为海相热成因型，产气页岩主要分布在前陆和克拉通盆地的泥盆—石炭系，埋藏深度一般为1 500~3 500 m。我国页岩分为海相、海陆过渡相与煤系、湖相三类，其中海相页岩主要发育在坳拉槽和克拉通盆地的下古生界，富有机质集中段分布稳定，热成熟度偏高，有较高的含气量，勘探前景最好；海陆过渡相与煤系页岩主要发育在大型坳陷和前陆盆地，层系以石炭系—侏罗系为主，没有明显的富有机质集中段，含气量差别较大，勘探潜力有待落实；湖相页岩主要发育在中、新生代陆相盆地，富有机质集中段厚度大，成熟度较高的凹陷中心区可能具有一定资源前景。预测我国页岩气勘探将经历较长的探索期，未来年产量可达500亿～600亿m3规模。

关键词： 页岩气     成藏条件     分布特征     富有机质页岩     中美对比     启示    

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Characteristics and energy distribution of modulated multi-pulse injection modes based diesel HCCI combustion

LIU Bin, SU Wanhua, WANG Hui, HUANG Haozhong

《能源前沿（英文）》 2007年 第1卷 第4期   页码 420-427 doi: 10.1007/s11708-007-0061-7

摘要： Cycle fuel energy distribution and combustion characteristics of early in-cylinder diesel homogenous charge compression ignition (HCCI) combustion organized by modulated multi-pulse injection modes are studied by the engine test.

关键词： combustion     compression     homogenous     in-cylinder     modulated multi-pulse    

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Enhanced dewatering characteristics of waste activated sludge with Fenton pretreatment: effectiveness

Guangyin ZHEN, Xueqin LU, Baoying WANG, Youcai ZHAO, Xiaoli CHAI, Dongjie NIU, Tiantao ZHAO

《环境科学与工程前沿（英文）》 2014年 第8卷 第2期   页码 267-276 doi: 10.1007/s11783-013-0530-3

摘要： In this work, the enhanced dewaterabing characteristics of waste activated sludge using Fenton pretreatment was investigated in terms of effectiveness and statistical optimization. Response surface method (RSM) and central composite design (CCD) were applied to evaluate and optimize the effectiveness of important operational parameters, i.e., H O concentrations, Fe concentrations and initial pH values. A significant quadratic polynomial model was obtained ( 0.9189) with capillary suction time (CST) reduction efficiency as the response. Numerical optimization based on desirability function was carried out. The optimum values for H O , Fe , and initial pH were found to be 178 mg·g VSS (volatile suspended solids), 211 mg·g VSS and 3.8, respectively, at which CST reduction efficiency of 98.25% could be achieved. This complied well with those predicted by the established polynomial model. The results indicate that Fenton pretreatment is an effective technique for advanced waste activated sludge dewatering. The enhancement of sludge dewaterability by Fenton’s reagent lies in the migration of sludge bound water due to the disintegration of sludge flocs and microbial cells lysis.

关键词： Fenton pretreatment     response surface methodology (RSM)     capillary suction time (CST)     dewaterabilty     molecular weight distribution    

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我国煤炭资源“井”字形分布特征与可持续发展战略

彭苏萍,张博,王佟

《中国工程科学》 2015年 第17卷 第9期   页码 29-35

摘要：

煤炭是我国的主体能源，科学地认识煤炭资源现状，需要对煤炭资源分布格局与赋存特征有系统的区划辨识，进而制订相应的可持续发展战略。研究发现，我国煤炭资源分布受东西向展布的天山—阴山、昆仑山—秦岭—大别山两条纬向构造带和南北向展布的大兴安岭—太行山—雪峰山、贺兰山—六盘山—龙门山两条经向构造带控制，呈“两横”和“两纵”相区隔的“井”字形分布特征。“井”字形区划格局不仅辨识了含煤盆地和煤炭资源的聚集与分布特征，还与区域自然地理、生态环境以及社会经济发展水平等要素直接关联。“井”字形区划格局下，中部晋陕蒙（西）宁区和蒙东区以及西部北疆区煤炭资源富集，勘探开发潜力巨大，而东部除黄淮海区少数省市以外，可供开发的煤炭资源面临枯竭。本文在系统分析我国煤炭资源发展面临的形势和问题的基础上，从攸关能源安全、生态安全和社会经济发展的角度，提出了实现我国煤炭资源可持续发展的战略思路、目标、重点实施路径以及相应的保障措施。

关键词： 煤炭资源；“井”字形分布；东部资源保护；可持续发展战略    

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Recovery of rare and precious metals from urban mines—A review

Mengmeng Wang, Quanyin Tan, Joseph F. Chiang, Jinhui Li

《环境科学与工程前沿（英文）》 2017年 第11卷 第5期 doi: 10.1007/s11783-017-0963-1

摘要： Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals (RPMs) from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional (pyrometallurgical, hydrometallurgical, and biometallurgical processing), and emerging (electrochemical, supercritical fluid, mechanochemical, and ionic liquids processing) technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used for RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies—electrochemical, supercritical fluid, ionic liquid, and mechanochemical—have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.

关键词： Rare and precious metals (RPMs)     Distribution characteristics     Recycling technology     Emerging technology     Supercritical fluid    

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中国古生代海相油气成藏特征

康玉柱

《中国工程科学》 2010年 第12卷 第5期   页码 11-17

摘要：

1970―1978年笔者在塔里木油气地质调研中首次提出古生代有发育的烃源岩，1984年沙参2井实现了古生代海相油田的首次重大突破。1992年通过多个古生代油气田深入研究建立了古生代海相油气成藏理论。其理论内涵：叠加复合盆地成藏，多时代多层系生油，多期成藏，多时代多类型储盖组合，多成藏模式，油气主要分布在古隆起、古斜坡、断裂带和不整合面附近。

关键词： 古生代     海相油气田     盆地     隆起     坳陷     油气分布    

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Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Jun Hu, Fengkui Duan, Kebin He, Yongliang Ma, Shuping Dong, Xiande Liu

《环境科学与工程前沿（英文）》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0861-y

摘要： Four types of S-rich particles are identified by SEM/FESEM-EDX With on-line observation, characteristics of S-rich particles are discovered Intensities of formation of S-rich particles are seasonally different Direct individual analysis using Scanning Electron Microscopy combined with online observation was conducted to examine the S-rich particles in PM of two typical polluted haze episodes in summer and winter from 2014 to 2015 in Beijing. Four major types of S-rich particles, including secondary CaSO particles (mainly observed in summer), S-rich mineral particles (SRM), S-rich water droplets (SRW) and (C, O, S)-rich particles (COS) were identified. We found the different typical morphologies and element distributions of S-rich particles and considered that (C, O, S)-rich particles had two major mixing states in different seasons. On the basis of the S-rich particles’ relative abundances, S concentrations and their relationships with PM as well as the seasonal comparison, we revealed that the S-participated formation degrees of SRM and SRW would enhance with increasing PM concentration. Moreover, C-rich matter and sulfate had seasonally different but significant impacts on the formation of COS.

关键词： S-rich particles     Morphology     Element distribution     Mixing state    

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Deformation field and crack analyses of concrete using digital image correlation method

Yijie HUANG, Xujia HE, Qing WANG, Jianzhuang XIAO

《结构与土木工程前沿（英文）》 2019年 第13卷 第5期   页码 1183-1199 doi: 10.1007/s11709-019-0545-3

摘要： The study on the deformation distribution and crack propagation of concrete under axial compression was conducted by the digital image correlation (DIC) method. The main parameter in this test is the water-cement ( / ) ratio. The novel analysis process and numerical program for DIC method were established. The displacements and strains of coarse aggregate, and cement mortar and interface transition zone (ITZ) were obtained and verified by experimental results. It was found that the axial displacement distributed non-uniformly during the loading stage, and the axial displacements of ITZs and cement mortar were larger than that of coarse aggregates before the occurrence of macro-cracks. The effect of / on the horizontal displacement was not obvious. Test results also showed that the transverse and shear deformation concentration areas (DCAs) were formed when stress reached 30%–40% of the peak stress. The transverse and shear DCAs crossed the cement mortar, and ITZs and coarse aggregates. However, the axial DCA mainly surrounded the coarse aggregate. Generally, the higher / was, the more size and number of DCAs were. The crack propagations of specimens varied with the variation of / . The micro-crack of concrete mainly initiated in the ITZs, irrespective of the / . The number and distribution range of cracks in concrete with high / were larger than those of cracks in specimen adopting low / . However, the value and width of cracks in high / specimen were relatively small. The / had an obvious effect on the characteristics of concrete deterioration. Finally, the characteristics of crack was also evaluated by comparing the calculated results.

关键词： deformation filed distribution     crack development     digital image correlation method     mechanical properties     water-cement ratio     characteristics of deformation and crack    

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Characterization of soil low-molecular-weight organic acids in the Karst rocky desertification region of Guizhou Province, China

Xiaoliang LI, Xiaomin CHEN, Xia LIU, Lianchuan ZHOU, Xinqiang YANG

《环境科学与工程前沿（英文）》 2012年 第6卷 第2期   页码 195-203 doi: 10.1007/s11783-012-0391-1

摘要： Soil low-molecular-weight (LMW) organic acids play important roles in the soil-forming process and the cycling of nutrients in Karst regions. In this study, we quantified the contents of LMW organic acids (including lactate, acetate, formate, malate, and oxalate) in soil solution over the Karst region of Guizhou Province, China using ion chromatography. The concentration of total LMW organic acids in topsoil solution ranged from 0.358 to 1.823 μmol·g , with an average of 0.912 μmol·g . The mean concentrations of lactate, acetate, formate, malate, and oxalate were 0.212±0.089, 0.302±0.228, 0.301±0.214, 0.014±0.018 and 0.086±0.118 μmol·g , respectively. There were also significant difference in the contents of these acids among four phases of rocky desertification, and their concentrations decreased with the aggravation of rocky desertification. The concentrations of the LMW organic acids were significantly positive correlated each other. Significant positive correlations were also observed among individual LMW organic acids in soil solution, and between them and soil available P, available K, exchangeable Ca, respectively. Furthermore, the concentrations of LMW organic acids were significantly positively correlated with inorganic anions (chlorides, nitrates, and sulfates) in Karst topsoil solution. Therefore, the concentrations of soil LMW organic acids might be one of driving force in the Karst rock desertification process in Guizhou Province.

关键词： Karst rocky desertification     low-molecular-weight (LMW) organic acids     distribution characteristics     soil    

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标题 作者 时间 类型 操作

Abundance, spatial distribution, and physical characteristics of microplastics in stormwater detention

期刊论文

Distribution, characteristics and daily fluctuations of microplastics throughout wastewater treatment

期刊论文

Distribution, enrichment mechanism and risk assessment for fluoride in groundwater: a case study of Mihe-Weihe

期刊论文

Design and characteristics of electric supercharger for diesel engine acceleration by additional rapid

YAO Chun-de, ZHOU Hong-xiu

期刊论文

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

期刊论文

CFD Simulation of thermal hydraulic characteristics in a typical upper plenum of RPV

Mingjun WANG, Lianfa WANG, Yingjie WANG, Wenxi TIAN, Jian DENG, Guanghui SU, Suizheng QIU

期刊论文

中美页岩气成藏条件、分布特征差异研究与启示

李建忠,李登华,董大忠,王社教

期刊论文

Characteristics and energy distribution of modulated multi-pulse injection modes based diesel HCCI combustion

LIU Bin, SU Wanhua, WANG Hui, HUANG Haozhong

期刊论文

Enhanced dewatering characteristics of waste activated sludge with Fenton pretreatment: effectiveness

Guangyin ZHEN, Xueqin LU, Baoying WANG, Youcai ZHAO, Xiaoli CHAI, Dongjie NIU, Tiantao ZHAO

期刊论文

我国煤炭资源“井”字形分布特征与可持续发展战略

彭苏萍,张博,王佟

期刊论文

Recovery of rare and precious metals from urban mines—A review

Mengmeng Wang, Quanyin Tan, Joseph F. Chiang, Jinhui Li

期刊论文

中国古生代海相油气成藏特征

康玉柱

期刊论文

Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Jun Hu, Fengkui Duan, Kebin He, Yongliang Ma, Shuping Dong, Xiande Liu

期刊论文

Deformation field and crack analyses of concrete using digital image correlation method

Yijie HUANG, Xujia HE, Qing WANG, Jianzhuang XIAO

期刊论文

Characterization of soil low-molecular-weight organic acids in the Karst rocky desertification region of Guizhou Province, China

Xiaoliang LI, Xiaomin CHEN, Xia LIU, Lianchuan ZHOU, Xinqiang YANG

期刊论文