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A method for quantifying bias in modeled concentrations and source impacts for secondary particulate matter

Cesunica E. Ivey, Heather A. Holmes, Yongtao Hu, James A. Mulholland, Armistead G. Russell

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0866-6

摘要: A method for quantifying source impacts for secondary PM species is derived. The method provides estimates of bias in modeled concentrations. Adjusted concentrations match corresponding observations at monitored locations. Sources impacts on secondary species are estimated over the US for 20 sources. Community Multi-Scale Air Quality (CMAQ) estimates of sulfates, nitrates, ammonium, and organic carbon are highly influenced by uncertainties in modeled secondary formation processes, such as chemical mechanisms, volatilization, and condensation rates. These compounds constitute the majority of PM mass, and reducing bias in estimated concentrations has benefits for policy measures and epidemiological studies. In this work, a method for adjusting source impacts on secondary species is developed that provides estimates of source contributions and reduces bias in modeled concentrations compared to observations. The bias correction adjusts concentrations and source impacts based on the difference between modeled concentrations and observations while taking into account uncertainties at the location of interest; and it is applied both spatially and temporally. We apply the method over the US for 2006. The mean bias for initial CMAQ concentrations compared to observations is −0.28 (OC), 0.11 (NO ), 0.05 (NH ), and −0.08 (SO ). The normalized mean bias in modeled concentrations compared to observations was effectively zero for OC, NO , NH , and SO after applying the secondary bias correction. 10-fold cross-validation was conducted to determine the performance of the spatial application of the bias correction. Cross-validation performance was favorable; correlation coefficients were greater than 0.69 for all species when comparing observations and concentrations based on kriged correction factors. The methods presented here address model uncertainties by improving simulated concentrations and source impacts of secondary particulate matter through data assimilation. Secondary-adjusted concentrations and source impacts from 20 emissions sources are generated for 2006 over continental US.

关键词: Particulate matter     Source apportionment     Secondary particulate matter     Chemical transport modeling     Receptor modeling    

Two-dimensional numerical and eco-toxicological modeling of chemical spills

Suiliang HUANG, Yafei JIA, Sam S. Y. WANG

《环境科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 178-185 doi: 10.1007/s11783-009-0020-9

摘要: The effects of chemical spills on aquatic non-target organisms were evaluated in this study. Based on a review of three types of current eco-toxicological models of chemicals, i.e., ACQUATOX model of the US-EPA, Hudson River Model of PCBs, and critical body residual (CBR) model and dynamic energy budget (DEBtox) model, this paper presents an uncoupled numerical eco-toxicological model. The transport and transformation of spilled chemicals were simulated by a chemical transport model (including flow and sediment transport), and the mortalities of an organism caused by the chemicals were simulated by the extended threshold damage model, separately. Due to extreme scarcity of data, this model was applied to two hypothetical cases of chemical spills happening upstream of a lake. Theoretical analysis and simulated results indicated that this model is capable of reasonably predicting the acute effects of chemical spills on aquatic ecosystems or organism killings.

关键词: chemical spills     acute effects     aquatic ecosystem     eco-toxicological modeling    

Mass transport mechanisms within pervaporation membranes

Yimeng Song, Fusheng Pan, Ying Li, Kaidong Quan, Zhongyi Jiang

《化学科学与工程前沿(英文)》 2019年 第13卷 第3期   页码 458-474 doi: 10.1007/s11705-018-1780-1

摘要: Pervaporation is an energy-efficient membrane technology for separating liquid molecules of similar physical properties, which may compete or combine with distillation separation technology in a number of applications. With the rapid development of new membrane materials, the pervaporation performance was significantly improved. Fundamental understanding of the mass transport mechanisms is crucial for the rational design of membrane materials and efficient intensification of pervaporation process. Based on the interactions between permeate molecules and membranes, this review focuses on two categories of mass transport mechanisms within pervaporation membranes: physical mechanism (solution-diffusion mechanism, molecular sieving mechanism) and chemical mechanism (facilitated transport mechanism). Furthermore, the optimal integration and evolution of different mass transport mechanisms are briefly introduced. Material selection and relevant applications are highlighted under the guidance of mass transport mechanisms. Finally, the current challenges and future perspectives are tentatively identified.

关键词: pervaporation membrane     mass transport mechanisms     physical mechanism     chemical mechanism    

Transport of bacterial cell (

Wei Fan, Qi Li, Mingxin Huo, Xiaoyu Wang, Shanshan Lin

《环境科学与工程前沿(英文)》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1242-0

摘要: Abstract • The recharge pond dwelling process induced changes in cell properties. • Cell properties and solution chemistry exerted confounding effect on cell transport. • E. coli cells within different recharge water displayed different spreading risks. Commonly used recharge water resources for artificial groundwater recharge (AGR) such as secondary effluent (SE), river water and rainfall, are all oligotrophic, with low ionic strengths and different cationic compositions. The dwelling process in recharge pond imposed physiologic stress on Escherichia coli (E. coli) cells, in all three types of investigated recharge water resources and the cultivation of E. coli under varying recharge water conditions, induced changes in cell properties. During adaptation to the recharge water environment, the zeta potential of cells became more negative, the hydrodynamic diameters, extracellular polymeric substances content and surface hydrophobicity decreased, while the cellular outer membrane protein profiles became more diverse. The mobility of cells altered in accordance with changes in these cell properties. The E. coli cells in rainfall recharge water displayed the highest mobility (least retention), followed by cells in river water and finally SE cells, which had the lowest mobility. Simulated column experiments and quantitative modeling confirmed that the cellular properties, driven by the physiologic state of cells in different recharge water matrices and the solution chemistry, exerted synergistic effects on cell transport behavior. The findings of this study contribute to an improved understanding of E. coli transport in actual AGR scenarios and prediction of spreading risk in different recharge water sources.

关键词: Artificial groundwater recharge     E. coli     Transport     Simulated column experiments     Modeling    

Modeling of Ce(IV) transport through a dispersion flat combined liquid membrane with carrier P507

Liang PEI,Liming WANG,Zhanying MA

《环境科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 503-509 doi: 10.1007/s11783-013-0540-1

摘要: A mathematical model for the transport of Ce(IV) from hydrochloric acid solutions through dispersion flat combined liquid membrane (DFCLM) with contain 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester (P507) as the carrier, dissolved in kerosene as the membrane solution have been studied. This process of facilitated transport, based on membrane technology, is a variation on the conventional technique of solvent extraction and may be described mathematically using Fick’s second law. The equations for transport velocity are derived considering the diffusion of P507 and its metallic complexes through the liquid membrane. In this work, the system is considered to be in a transient state, and chemical reaction between Ce(IV) and the carrier to take place only at the solvent–aqueous interfaces. Model concentration profiles are obtained for the Ce(IV), from which extraction velocities are predicted. The experimental and simulated Ce(IV) extractions showed similar tendencies for a high Ce(IV) concentration and acidity case.The model results indicate that high initial Ce(IV) concentrations and acidity both have detrimental effects on Ce(IV) extraction and stripping. The diffusion coefficient of Ce(IV) in the membrane and the thickness of diffusion layer between feed phase and membrane phase are obtained and the values are 6.31 × 10 m ·s and 31.2 μm, respectively. The results are in good agreement with experimental results.

关键词: Dispersion flat combined liquid membrane (DFCLM)     dispersion phase     feed phase     2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester     Ce (IV)    

极端条件下材料化学和输运性质的第一原理研究 Review

John S. Tse

《工程(英文)》 2019年 第5卷 第3期   页码 421-433 doi: 10.1016/j.eng.2019.01.008

摘要:

地球是一个动态系统。从常温常压到地核的360 GPa 和6600 K,地球的热力学状态随着深度的变化而发生很大变化。因此,地球成分(如硅酸盐和碳酸盐矿物)的物理和化学性质受其所处环境的显著影响。在过去的30 年中,在极端条件下的材料表征的实验技术和理论模拟方法都取得了巨大的进步。这些进步提升了我们对矿物特性的理解,这对于充分认识这个星球的形成及其生命起源至关重要。本文回顾了用于预测极端条件下材料性质的最新计算技术,本研究仅限于应用第一原理分子动力学(first principle molecular dynamics, FPMD)方法研究与地球科学相关的化学和热力学输运过程。

关键词: 高压     高温     地幔     分子动力学     密度泛函方法     输运性质     化学反应    

Relations between indoor and outdoor PM

Cong Liu, Yinping Zhang

《环境科学与工程前沿(英文)》 2019年 第13卷 第1期 doi: 10.1007/s11783-019-1089-4

摘要:

Factors impacting indoor-outdoor relations are introduced.

Sulfate seems a fine tracer for other non-volatile species.

Particulate nitrate and ammonium desorb during outdoor-to-indoor transport.

OC load increases during the transport due to sorption of indoor SVOCs.

关键词: Indoor air quality     Exposure     SVOC     Reactive oxidative species     Oxidative potential     Chemical transport model    

Application of adaptive neuro-fuzzy inference system and cuckoo optimization algorithm for analyzing electro chemical

Reza TEIMOURI, Hamed SOHRABPOOR

《机械工程前沿(英文)》 2013年 第8卷 第4期   页码 429-442 doi: 10.1007/s11465-013-0277-3

摘要:

Electrochemical machining process (ECM) is increasing its importance due to some of the specific advantages which can be exploited during machining operation. The process offers several special privileges such as higher machining rate, better accuracy and control, and wider range of materials that can be machined. Contribution of too many predominate parameters in the process, makes its prediction and selection of optimal values really complex, especially while the process is programmized for machining of hard materials. In the present work in order to investigate effects of electrolyte concentration, electrolyte flow rate, applied voltage and feed rate on material removal rate (MRR) and surface roughness (SR) the adaptive neuro-fuzzy inference systems (ANFIS) have been used for creation predictive models based on experimental observations. Then the ANFIS 3D surfaces have been plotted for analyzing effects of process parameters on MRR and SR. Finally, the cuckoo optimization algorithm (COA) was used for selection solutions in which the process reaches maximum material removal rate and minimum surface roughness simultaneously. Results indicated that the ANFIS technique has superiority in modeling of MRR and SR with high prediction accuracy. Also, results obtained while applying of COA have been compared with those derived from confirmatory experiments which validate the applicability and suitability of the proposed techniques in enhancing the performance of ECM process.

关键词: electrochemical machining process (ECM)     modeling     adaptive neuro-fuzzy inference system (ANFIS)     optimization     cuckoo optimization algorithm (COA)    

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    

聚酰胺反渗透膜中水传递阻力的分子模拟——界面阻力和内部阻力 Article

宋阳, 魏明杰, 徐放, 汪勇

《工程(英文)》 2020年 第6卷 第5期   页码 577-584 doi: 10.1016/j.eng.2020.03.008

摘要:

在分子水平上理解水分子在聚酰胺(PA)反渗透(RO)膜中的传递阻力对于这些膜的设计、制备和应用具有非常重要的指导意义。本文通过分子模拟来计算总传递阻力,并将其分成两部分——内部阻力和界面阻力。内部阻力取决于PA层的厚度,而界面阻力则不然。基于5 nm 厚的PA层的模拟显示界面阻力对总阻力的贡献率很大(> 62%)。然而,现实世界中,对于具有200 nm PA层的RO膜,界面阻力起次要作用,其贡献率低于10%。这表明,当使用典型方法估算RO膜的传递阻力时,存在不准确的风险,因为该方法简单地将5 nm厚的PA层的总阻力进行倍增,使得界面阻力被错误放大。此外,界面阻力和内部阻力均取决于PA层的化学性质。我们的模拟显示,减少PA层中剩余羧基的数量会导致内部阻力降低,因此,可以在不牺牲离子截留的情况下改善水的渗透性,这与实验结果高度吻合。

关键词: 传递阻力     反渗透     非平衡分子动力学     水分子亲水性     建模    

Intercontinental transport of air pollution

Lin ZHANG,

《环境科学与工程前沿(英文)》 2010年 第4卷 第1期   页码 20-29 doi: 10.1007/s11783-010-0014-7

摘要: There is an increasing interest on the intercontinental transport of air pollution among the three main emission regions at northern mid-latitudes: North America, Europe, and East Asia. Air pollutants with sufficient long lifetime can be transported from one continent to another. Observations from ground sites, aircraft and satellites have demonstrated this intercontinental-scale transport of air pollutants in the free troposphere. Numerical models have been applied to understand the pathways of the transport and the impact of intercontinental pollution transport. This paper reviews current observational evidence and modeling studies of intercontinental transport of ozone and its precursors, and the resulting impacts on air quality.

关键词: intercontinental transport     ozone     air pollution    

Future urban transport management

《工程管理前沿(英文)》   页码 534-539 doi: 10.1007/s42524-023-0255-3

摘要: The incorporation of disruptive innovations into the transportation industry will inevitably cause major upheavals in the transportation sector. However, existing research lacks systematic theories and methodologies to represent the underlying characteristics of future urban transport systems. Furthermore, emerging modes in urban mobility have not been sufficiently studied. The National Natural Science Foundation of China (NSFC) officially approved the Basic Science Center project titled “Future Urban Transport Management” in 2022. The project members include leading scientists and engineers from Beijing Jiaotong University, Beihang University, and Beijing Transport Institute. Based on a wide range of previous projects by the consortium on urban mobility and sustainable cities, this project will encompass transdisciplinary and interdisciplinary research to explore critical issues affecting future urban traffic management. It aims to develop fundamental theories and methods based on social and technological developments in the near future and explores innovative solutions to implement alongside these emerging developments in urban mobility.

关键词: future urban transport management     travel behavior characteristics     transportation operations     transportation emergency management     transportation decision intelligence    

Thermal transport properties of monolayer phosphorene: a mini-review of theoretical studies

Guangzhao QIN, Ming HU

《能源前沿(英文)》 2018年 第12卷 第1期   页码 87-96 doi: 10.1007/s11708-018-0513-y

摘要: Phosphorene, a two-dimensional (2D) elemental semiconductor with a high carrier mobility and intrinsic direct band gap, possesses fascinating chemical and physical properties distinctively different from other 2D materials. Its rapidly growing applications in nano-/opto-electronics and thermoelectrics call for fundamental understanding of the thermal transport properties. Considering the fact that there have been so many studies on the thermal transport in phosphorene, it is on emerging demand to have a review on the progress of previous studies and give an outlook on future work. In this mini-review, the unique thermal transport properties of phosphorene induced by the hinge-like structure are examined. There exists a huge deviation in the reported thermal conductivity of phosphorene in literature. Besides, the mechanism underlying the deviation is discussed by reviewing the effect of different functionals and cutoff distance in calculating the thermal transport properties of phosphorene. It is found that the (vdW) interactions play a key role in the formation of resonant bonding, which leads to long-ranged interactions. Taking into account of the vdW interactions and including the long-ranged interactions caused by the resonant bonding with large cutoff distance are important for getting the accurate and converged thermal conductivity of phosphorene. Moreover, a fundamental insight into the thermal transport is provided based on the review of resonant bonding in phosphorene. This mini-review summarizes the progress of the thermal transport in phosphorene and gives an outlook on future horizons, which would benefit the design of phosphorene based nano-electronics.

关键词: thermal transport     phosphorene     resonant bonding    

EFFECTS OF TRANSPORT STRESS ON THE INTESTINES INVOLVING NEURONAL NITRIC OXIDE SYNTHASE

《农业科学与工程前沿(英文)》   页码 285-295 doi: 10.15302/J-FASE-2022469

摘要:

● Transport stress declined the level of leukocytes including lymphocytes in rat serum.

关键词: intestine     nNOS     nNOS-positive neurons     transport stress    

Numerical simulations of morphological changes in barrier islands induced by storm surges and waves using a supercritical flow model

Soumendra Nath KUIRY, Yan DING, Sam S Y WANG

《结构与土木工程前沿(英文)》 2014年 第8卷 第1期   页码 57-68 doi: 10.1007/s11709-014-0235-0

摘要: In this paper, an advanced explicit finite volume flow model in two-dimensions is presented for simulating supercritical coastal flows and morphological changes in a tidal/coastal inlet and barrier islands due to storm surges and waves. This flow model is coupled with existing wave-action model and sediment transport model. The resulting integrated coastal process model is capable of simulating flows induced by extreme conditions such as waves, surge tides, river flood flows, etc., and morphological changes induced by rapid coastal currents and waves. This developed supercritical flow model is based on the solution of the conservative form of the nonlinear shallow water equations with the effects of the Coriolis force, uneven bathymetry, wind stress, and wave radiation stresses. The forward Euler scheme is used for the unsteady term; and the convective term is discretized using the Godunov-type shock-capturing scheme along with the HLL Riemann solver on non-uniform rectilinear grids. The accuracy of the developed model is investigated by solving an experimental dam-break test case. Barrier island breaching, overflow and overwash due to severe storm attack are simulated and the predicted morphological changes associated to the events are analyzed to investigate the applicability of the model in a coast where all the physical forces are present.

关键词: coastal inlet     coastal process modeling     supercritical flow     sediment transport     barrier islands    

标题 作者 时间 类型 操作

A method for quantifying bias in modeled concentrations and source impacts for secondary particulate matter

Cesunica E. Ivey, Heather A. Holmes, Yongtao Hu, James A. Mulholland, Armistead G. Russell

期刊论文

Two-dimensional numerical and eco-toxicological modeling of chemical spills

Suiliang HUANG, Yafei JIA, Sam S. Y. WANG

期刊论文

Mass transport mechanisms within pervaporation membranes

Yimeng Song, Fusheng Pan, Ying Li, Kaidong Quan, Zhongyi Jiang

期刊论文

Transport of bacterial cell (

Wei Fan, Qi Li, Mingxin Huo, Xiaoyu Wang, Shanshan Lin

期刊论文

Modeling of Ce(IV) transport through a dispersion flat combined liquid membrane with carrier P507

Liang PEI,Liming WANG,Zhanying MA

期刊论文

极端条件下材料化学和输运性质的第一原理研究

John S. Tse

期刊论文

Relations between indoor and outdoor PM

Cong Liu, Yinping Zhang

期刊论文

Application of adaptive neuro-fuzzy inference system and cuckoo optimization algorithm for analyzing electro chemical

Reza TEIMOURI, Hamed SOHRABPOOR

期刊论文

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

期刊论文

聚酰胺反渗透膜中水传递阻力的分子模拟——界面阻力和内部阻力

宋阳, 魏明杰, 徐放, 汪勇

期刊论文

Intercontinental transport of air pollution

Lin ZHANG,

期刊论文

Future urban transport management

期刊论文

Thermal transport properties of monolayer phosphorene: a mini-review of theoretical studies

Guangzhao QIN, Ming HU

期刊论文

EFFECTS OF TRANSPORT STRESS ON THE INTESTINES INVOLVING NEURONAL NITRIC OXIDE SYNTHASE

期刊论文

Numerical simulations of morphological changes in barrier islands induced by storm surges and waves using a supercritical flow model

Soumendra Nath KUIRY, Yan DING, Sam S Y WANG

期刊论文