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INSITU, RAPID RESPONSE MEASUREMENT OF H2SO4/(NH4)2SO4 AEROSOLS IN URBAN HOUSTON - A COMPARISON WITH RURAL VIRGINIA

ATMOSPHERIC ENVIRONMENT 1983年第9期17卷 1723-1731页

作者： WAGGONER, AP WEISS, RE LARSON, TV Department of Civil Engineering FC-05 Environmental Engineering and Science Program University of Washington Seattle WA 98195 U.S.A.

We report measurements taken in Houston, Texas of the chemical composition and degree of hydration of haze particles and compare these results with previously reported measurements taken in rural Virginia. Our in-situ, real time measurements are based on detecting changes in particle light scattering extinction with changes in relative humidity and air temperature. With these methods we can determine fine particle mass and sulfate mass concentrations, and sulfate to ammonium ion molar ratio. In Houston, fine particle sulfate averaged 42 % of fine particle mass and the composition in terms of ammonium to sulfate molar ratio ranged from 0.5 to 2 with strong diurnal variation. The particles were most acid during the period 1500 to 2000 and neutral during 0200 to 0900. About 1 3 of the time the particles were droplets supersaturated in terms of salt content. In Virginia, the particles were on average more acidic and contained more water than those in Houston, but the particles were never observed to be supersaturated solution droplets. The difference in the hygroscopic behavior of the particles at the two sites is consistent with differences in both particle chemistry and ambient relative humidity.

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Initiation of ice jam in front of bridge piers-An experimental study

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Journal of Hydrodynamics 2019年第1期31卷 117-123页

作者： Jun Wang Jian Hua Pang-pang Chen Jueyi Sui Peng Wu Todd Whitcombe College of Civil and Hydraulic Engineering Hefei University of TechnologyHefei 230009China Modern Green Development Co.LTD Beijing 100028China Environmental Sciences and Engineering Program University of Northern British ColumbiaPrince GeorgeBCCanada Environmental System Engineering Program University of ReginaReginaCanada

The presence of bridge piers in natural rivers significantly changes the flow and boundary *** a consequence,ice jams can often be initiated in front of bridge *** the changes in flow conditions,two types of ice jam formation may appear:surface accumulation of ice blocks (surface ice blockage) and thickened accumulation of ice blocks (vertical ice blockage).In the present study,the initiation process of ice jam was studied based on *** is found that the critical ice concentration for ice jam blockage depends on the ice block dimension,channel opening and flow *** surface blockage conditions,a larger ratio of ice cube dimension to channel opening (between piers) can result in a smaller critical ice concentration for ice jam blockage,which has no obvious relation with flow *** vertical blockage conditions,the critical ice concentration for ice jam blockage increases with flow Froude number and decreases with the ratio of ice dimension to channel opening (between piers).Based on experiments conducted in laboratory,equations for determining critical ice concentration for these two types of ice jam blockage have been developed.

关键词： Bridge piers surface ice blockage vertical ice blockage critical ice concentrations

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THE UPTAKE, TRANSLOCATION AND RELEASE OF PHOSPHORUS BY ELODEA-DENSA

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HYDROBIOLOGIA 1984年第1期111卷 43-48页

作者： GABRIELSON, JO PERKINS, MA WELCH, EB Department of Civil Engineering FX-10 Environmental Engineering and Science Program University of Washington 98195 Seattle WA U.S.A.

Short-term (16 h) laboratory studies of 32P uptake by E. densa rooted in sediment demonstrated both foliar and root uptake, and that translocation occurred acropetally and basipetally. Root absorption is projected to provide 83-85% of total P uptake during 12-16 h photoperiod days. Measured foliar uptake and excretion rates suggest that there would be no net leakage of P into the water by undamaged actively-growing E. densa. Foliar uptake decreased and root uptake increased in the dark relative to rates under light.

关键词： phosphorus cycling macrophytes absorption sediment phosphorus

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ON THE EVAPORATION OF AMMONIUM-NITRATE AEROSOL

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ATMOSPHERIC ENVIRONMENT 1983年第12期17卷 2489-2495页

作者： LARSON, TV TAYLOR, GS Environmental Engineering and Science Program Department of Civil Engineering FC-05 University of Washington Seattle WA 98195 U.S.A.

Gaseous NH 3 and HNO 3 were continuously and rapidly removed from an aerosol containing small, aqueous solution droplets of NH 4 NO 3 (MMD = 0.4 μm), resulting in evaporation of the NH 4 NO 3 from the droplets. The rate of evaporation was measured by following changes in the size distribution of the aerosol with time. The measured rates agree well with those predicted from existing theories of gaseous diffusion and concentrated solution chemistry. The resulting ‘evaporation’ coefficient for both NH 3 and HNO 3 was unity, implying that resistance to transport of molecules across the vapor-liquid interface is small. The observed rates imply negligible sampling errors from evaporation of NH 4 NO 3 in gas denuder tubes used in atmospheric measurements of HNO 3 and particulate nitrate compounds.

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OZONE DOSE-RESPONSE OF ESCHERICHIA-COLI IN ACTIVATED-SLUDGE EFFLUENT

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WATER RESEARCH 1989年第8期23卷 1017-1025页

作者： FINCH, GR SMITH, DW Environmental Engineering and Science Program Department of Civil Engineering University of Alberta Edmonton Alberta Canada T6G 2G7

The response of E. coli ATCC 11775 in activated sludge effluent to various doses of ozone and for various contact times was studied using batch and semi-batch reactors at bench-scale and pilot-scale under controlled environmental conditions. The results indicated that there was no significant effect associated with contact time or scale. Also, the empirical dose-response model form described by the U.S. environmental Protection Agency for sizing ozone wastewater disinfection systems was found to have lack-of-fit over the experimental region studied. The inadequacy of the model was confirmed at both scales. It was found that the bench-scale experiments provided a reasonable estimate of the required ozone dose to achieve a specified reduction of bacteria thereby potentially eliminating the need for costly pilot-scale feasibility studies in many cases.

关键词： ozone disinfection dose-response Escherichia coli faecal coliform water wastewater model

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Mechanisms of ice accumulation in a river bend-an experimental study

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International Journal of Sediment Research 2012年第4期27卷 521-537页

作者： Jun WANG Jue-yi SUI Hong-ya ZHANG Pang-pang CHEN Faye HIRSHFIELD School of Civil Engineering Hefei University of Technology Environmental Engineering Program University of Northern British Columbia Prince George Anhui Institute of Architectural and Industry Environmental Science Program University of Northern British Columbia Prince George

In this study,under conditions of different flow and ice discharge,extensive experiments have been carried out in a 180°-bend flume and an S-shaped bend *** phenomenon and mechanisms of ice accumulation in the bend channel have been *** accumulation along the convex bank was normally thicker than that along the concave *** maximum thickness of ice accumulation in the downstream bend channel occurred close to the convex *** difference between the maximum thickness and the minimum thickness of ice accumulation was *** entire ice accumulation became unstable if flow Froude number was *** the flow Froude Number is high,the entire ice accumulation becomes *** Froude Number between 0.035 and 0.060,the bottom surface of ice accumulation became waved in *** changes in Froude number and ice discharge rate can change a channel from a state of no ice accumulation to uniform accumulation over the channel *** higher the ice discharge,the more uniform the ice *** experimental results have been compared with field observations of ice jams at the Hequ Reach of the Yellow River.

关键词： 180°bend flume Frazil ice Ice jam or ice accumulation S-shape bend channel Thickness profile

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Preliminary Analysis of Blackwater and Greywater Characteristics in the Jakarta Greater Region Area

Preliminary Analysis of Blackwater and Greywater Characteris...

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International Conference on Sustainable Insfrastructure 2018, ICSI 2018

作者： Hafiza, N. Abdillah, A. Islami, B.B. Priadi, C.R. Environmental Engineering Study Program Civil and Environmental Engineering Department Faculty of Engineering Universitas Indonesia Depok Indonesia

Domestic wastewater contributes about 40% as the source of water bodies pollutants in Indonesia, causing the spread of pathogens and bioaccumulation effects on the environment. The purpose of this study was to analyze the characteristics of household wastewater in Jakarta and Depok in terms of quantity and quality. The average wastewater quantity estimation results from laundry, bathroom, kitchen, and closet were 49 ± 18, 79.1 ± 5, 24.5 ± 12, and 29.9 ± 3 liters/person/day. The qualitative analysis results stated that blackwater tends to have higher concentration on conductivity 1606-2046 μs/cm, TDS 709-1007 mg/L, ammonia 78-167 mg/L, total nitrogen 511-836 mg/L, total phosphorus 16.6-21.3 mg/L, phosphate 33-46.8 mg/L, potassium 32.5-47.9 mg/L, and fecal coliform 430,000-1.600,000 MPN/100 mL compared to other sources. Meanwhile, laundry greywater tends to have higher concentration on COD 559-1991.6 mg/L, MBAS 0.3-0.31 mg/L, aluminum 1.65-5.09 mg/L, sodium 7.5-61.4 mg/L, and silica 17.7-23.2 mg/L compared to other sources. Statistical results show that some parameters have significant difference in average concentration between each source so that these parameters can be considered as source tracer. The high pollutant concentration and quantity leads to high estimation of pollutant load on the river, as water bodies receiver, in Jakarta and Depok, especially on organic and nutrient load. © 2019 Published under licence by IOP Publishing Ltd.

关键词： Silica

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Impacts of vegetation over bedforms on flow characteristics in gravel-bed rivers

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Journal of Hydrodynamics 2019年第5期31卷 986-998页

作者： Hossein Afzalimehr Mohammad Reza Maddahi Jueyi Sui Majid Rahimpour Department of Civil Engineering Iran University of Science and TechnologyTehranIran Department of Water Engineering Shahid Bahonar University of KermanKermanIran Environmental Engineering Program University of Northern British ColumbiaCanada

In the present study,among six gravel-bed river reaches,two natural gravel-bed river reaches with approximately similar bedforms and flow conditions have been found,one river reach with vegetation on bedforms and the other without vegetation on *** on field measurements,the impacts of vegetation over bedforms on flow characteristics have been *** velocity,Reynolds stress and turbulence intensity distributions over bedforms with vegetation have been compared with those over gravel bedforms without *** using the quadrant analysis,the dominant events of turbulent flow structures have been assessed for flows over gravel bedforms with vegetation and without *** show that the effect of vegetation enhances the anisotropy in turbulence and generates strong secondary currents,which lead to the occurrence of dip phenomenon at the stoss section and the crest of vegetated *** change of bed roughness from gravel bed to vegetated bed causes a development of a new boundary *** resulted in the different shape of velocity distributions over bedforms with vegetation from those over bedforms without vegetation,which can affect the lives of aquatic *** shear stress at downstream section of gravel bedform without vegetation is much higher than that of vegetated bedform,which shows that the erosion takes place from downstream of vegetated bedforms,while in the bare beds;the deposition is at downstream of *** is found that the presence of vegetation causes a chaotic distribution pattern of Reynolds shear stress,while it has more orderly pattern at the downstream section of gravel bedform without ***,the distribution of turbulence intensity in the lee side of vegetated bedform has a concave shape and in the stoss section,turbulence is generated in ejections and sweeps near the vegetation *** findings are significant to the practice of river ecological restoration.

关键词： Bedform Reynolds shear stress distribution turbulence intensity vegetation velocity profiles

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CIWARS: A Web Server for Antibiotic Resistance Surveillance Using Longitudinal Metagenomic Data

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Journal of Molecular Biology 2025年

作者： Emon, Muhit Islam Cheung, Yat Fei Stoll, James Rumi, Monjura Afrin Brown, Connor Choi, Joung Min Moumi, Nazifa Ahmed Ahmed, Shafayat Song, Haoqiu Sein, Justin Yao, Shunyu Khan, Ahmad Gupta, Suraj Kulkarni, Rutwik Butt, Ali Vikesland, Peter Pruden, Amy Zhang, Liqing Department of Computer Science Virginia Tech Blacksburg 24060 VA United States Fralin Life Science Institute Virginia Tech Blacksburg 24060 VA United States Department of Civil and Environmental Engineering Virginia Tech Blacksburg 24060 VA United States The Interdisciplinary PhD Program in Genetics Bioinformatics and Computational Biology Virginia Tech Blacksburg 24060 VA United States

The rise of antibiotic resistance (AR) poses a substantial threat to human and animal health, food security, and economic stability. Wastewater-based surveillance (WBS) has emerged as a powerful strategy for population-level AR monitoring, providing valuable data to guide public health and policy decisions. Metagenomic sequencing is especially promising, as it can yield comprehensive profiles of antibiotic resistance genes (ARGs) and other genes relevant to AR in a single run. However, online analytical platforms to facilitate analysis of longitudinal metagenomic data are lacking. To address this, we introduce CyberInfrastructure for Waterborne Antibiotic Resistance Surveillance (CIWARS), a web server configured for characterizing key AR trends from longitudinal metagenomic WBS data. CIWARS offers comprehensive profiling of ARGs and taxonomic profiling of pathogen-associated bacterial taxonomic groups, identifies potential associations of ARGs with mobile genetic elements (MGEs) and pathogen-containing taxa, and assesses resistome risk based on the co-occurrence of ARGs, MGEs, and pathogen-like sequences. Additionally, it detects anomalous AR indicators over time, aiding in identifying potential events of concern, such as the emergence of resistant strains or outbreaks. Through interactive temporal data visualization, CIWARS enables AR monitoring and can serve as a tool to inform effective and timely interventions to mitigate the spread and transmission of AR. Here, CIWARS is demonstrated using longitudinal metagenomic data from a wastewater treatment plant (WWTP) influent and effluent, but it can be extended to any environment. CIWARS provides a valuable tool to support global efforts to combat the evolution and spread of AR, while also guiding agricultural and public health efforts aimed at optimizing antibiotic use. The web server is freely available at https://***/. © 2025 Elsevier Ltd

关键词： anomaly detection antibiotic resistance (AR) AR indicator profiling longitudinal metagenomics wastewater-based surveillance

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Dimensionality reduction and prediction of soil consolidation coefficient using random forest coupling with Relief algorithm

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Frontiers of Structural and civil engineering 2022年第2期16卷 224-238页

作者： Hai-Bang LY Huong-Lan Thi VU Lanh Si HO Binh Thai PHAM Department of Civil Engineering University of Transport TechnologyHanoi100000Vietnam Civil and Environmental Engineering Program Hiroshima UniversityHiroshima739-8527Japan Department of Science Technology and International CooperationUniversity of Transport TechnologyHanoi100000Vietnam

The consolidation coefficient of soil(C_(v))is a crucial parameter used for the design of structures leaned on soft *** general,the C_(v) is determined experimentally in the ***,the experimental tests are time-consuming as well as ***,researchers tried several ways to determine C_(v) via other simple soil *** this study,we developed a hybrid model of Random Forest coupling with a Relief algorithm(RF-RL)to predict the C_(v) of *** conduct this study,a database of soil parameters collected from a case study region in Vietnam was used for *** performance of the proposed models was assessed via statistical indicators,namely Coefficient of determination(R^(2)),Root Mean Squared Error(RMSE),and Mean Absolute Error(MAE).The proposal models were constructed with four sets of soil variables,including 6,7,8,and 13 *** results revealed that all models performed well with a high performance(R^(2)>0.980).Although the RF-RL model with 13 variables has the highest prediction accuracy(R^(2)=0.9869),the difference compared with other models was negligible(i.e.,R^(2)=0.9824,0.9850,0.9825 for the cases with 6,7,8 inputs,respectively).Thus,it can be concluded that the hybrid model of RF-RL can be employed to predict C_(v) based on the basic soil parameters.

关键词： soil consolidation coefficient machine learning random forest Relief

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