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Articles 4651 - 4680 of 6122

Full-Text Articles in Civil and Environmental Engineering

Assessing Near-Field Black Carbon Variability Due To Wood Burning And Evaluating Regression Models And Isc Dispersion Modeling, Stella Tan Sep 2011

Assessing Near-Field Black Carbon Variability Due To Wood Burning And Evaluating Regression Models And Isc Dispersion Modeling, Stella Tan

Master's Theses

PM2.5 variability within the neighborhood scale has not been thoroughly studied for wood burning communities. High variability in near-field PM2.5 concentration may lead to harmful public exposure since monitoring does not occur on that scale. This study measures near-field PM2.5 variability by measuring black carbon (BC), a component of PM2.5, in a 1 km2 area located in Cambria, California. BC and meteorological data (when meteorological instruments were available) were measured over thirteen 12-hour intensive operation periods (IOPs) occurring over the winters of 2009 and 2010. Near-field BC variability was measured to understand the type …


A Field And Modeling Assessment Of Methyl Mercury Accumulation In An Engineered Retention Pond, Lauren C. Blazeck Aug 2011

A Field And Modeling Assessment Of Methyl Mercury Accumulation In An Engineered Retention Pond, Lauren C. Blazeck

Master's Theses

The accumulation of methyl mercury (MeHg) in lakes during summer stratification has been demonstrated to affect biotic mercury (Hg) accumulation. However, small, shallow polymictic lakes can experience short-term stratification and mixing events that are largely unstudied in their abilities to affect Hg cycling and MeHg accumulation. Short-term stratification events and changing lake characteristics impact lake biogeochemical cycles, and therefore, MeHg production and transport. A field and modeling analysis was performed on a small suburban lake located on the University of Connecticut campus to determine the impact of lake characteristics on the potential for MeHg accumulation. MeHg concentrations ranged from non-detect …


Dissolved Organic Matter Characterization And Impact On Mercury Binding In An Urbanizing Watershed, Mykel Mendes Aug 2011

Dissolved Organic Matter Characterization And Impact On Mercury Binding In An Urbanizing Watershed, Mykel Mendes

Master's Theses

Dissolved organic matter (DOM) is ubiquitous in aquatic ecosystems, interacting with and controlling the bioavailability and transport of mercury (Hg) and other trace metals through complexation. The complexation of ionic Hg (Hg2+) with DOM can either limit methyl mercury (MeHg) bioavailability or increase MeHg production by stimulating microbial growth. While substantial investigations have examined Hg-DOM interactions in forested ecosystems, little research has been conducted on the Hg-DOM relationship within an urbanized river setting subjected to various anthropogenic sources. The various runoff and pollutant sources vary in DOM quality and character. Three sources of organic matter from the North …


Constitutive Model For Rate Dependent Behavior Of Clay Internal Geotechnical Report 2011-3, Harry Martindale, Dipanjan Basu Aug 2011

Constitutive Model For Rate Dependent Behavior Of Clay Internal Geotechnical Report 2011-3, Harry Martindale, Dipanjan Basu

Technical Reports

This report presents a strain-rate dependent plastic constitutive model for clays. Based on the concepts of critical-state soil mechanics and bounding surface plasticity theory, the model reproduces the mechanical response of clays under multi-axial loading conditions and predicts both the drained and undrained behavior. The model parameters are determined for Boston Blue Clay, London Clay and Kaolin Clay, and the performance of the model in simulating the mechanical response of these clays is demonstrated for low to medium strain rates. The sensitivity of each model parameter is checked by perturbing the calibrated values by ±20%. Subsequently, a probabilistic analysis using …


A High Strain-Rate Constitutive Model For Sand With Application In Finite Element Analysis Internal Geotechnical Report 2011-4, William Higgins, Dipanjan Basu Aug 2011

A High Strain-Rate Constitutive Model For Sand With Application In Finite Element Analysis Internal Geotechnical Report 2011-4, William Higgins, Dipanjan Basu

Technical Reports

The report presents a constitutive model for simulating the high strain-rate behavior of sands. Based on the concepts of critical-state soil mechanics, the bounding surface plasticity theory and the overstress theory of viscoplasticity, the constitutive model simulates the high strain-rate behavior of sands under uniaxial, triaxial and multiaxial loading conditions. The model parameters are determined for Ottawa and Fontainebleau sands, and the performance of the model under extreme transient loading conditions is demonstrated through simulations of split Hopkinson pressure bar tests up to a strain rate of 2000/sec. The constitutive model is implemented in a finite element analysis software to …


Empirical Critical Loads Of Atmospheric Nitrogen Deposition For Nutrient Enrichment And Acidification Of Sensitive Us Lakes, Jill S. Baron, Charles T. Driscoll, John L. Stoddard, Eric E. Richer Aug 2011

Empirical Critical Loads Of Atmospheric Nitrogen Deposition For Nutrient Enrichment And Acidification Of Sensitive Us Lakes, Jill S. Baron, Charles T. Driscoll, John L. Stoddard, Eric E. Richer

Civil and Environmental Engineering - All Scholarship

No abstract provided.


A History-Dependent Nonwetting Phase Trapping Model For Multiphase Flow Characteristic Curves, Christopher Patterson Aug 2011

A History-Dependent Nonwetting Phase Trapping Model For Multiphase Flow Characteristic Curves, Christopher Patterson

All Theses

Characteristic curves used in numerical multiphase flow simulators describe relative permeability-saturation and capillary pressure-saturation relationships for flow simulations. Characteristic curves are typically non-hysteretic; meaning they are monotonic functions of saturation and are limited to a single value for residual saturation. Implications of residual saturation are important for environmental, petroleum, and geologic carbon sequestration modeling. However, hysteretic characteristic curves predict that trapped residual saturation depends on the local saturation history. The use of hysteretic characteristic curves is critical to predicting the residual saturation and ultimately the mobility of a nonwetting phase such as supercritical CO2 or a nonaqueous phase liquid (NAPL). …


Influence Of Natural Organic Matter On Plutonium Sorption To Gibbsite, Laura Simpkins Aug 2011

Influence Of Natural Organic Matter On Plutonium Sorption To Gibbsite, Laura Simpkins

All Theses

Understanding plutonium geochemical behavior is imperative to the development of schemes for remediation of plutonium environmental contamination and accurate assessment of risks posed by the disposal of plutonium bearing wastes. The primary mechanism of plutonium mobility in the environment is subsurface transport. The mobility of plutonium is significantly influenced by redox and complexation reactions. Although the effects of surface mediated redox reactions on plutonium's subsurface mobility have been previously documented, little has been done to determine the impact of organic materials on sorption behavior and oxidation states. To adequately predict the behavior of plutonium in the environment, the influence of …


Determination Of Freshwater Algal Biomass And Sulfolipid Content As Functions Of Inorganic Carbon Treatment, Melissa Morella Aug 2011

Determination Of Freshwater Algal Biomass And Sulfolipid Content As Functions Of Inorganic Carbon Treatment, Melissa Morella

All Theses

Cultures of mixed freshwater algae were grown in open batch reactors made up of modified BG-11 media that contained 0, 25, 50 or 100% of the suggested inorganic carbon content (0, 0.5, 0.1 and 0.2 g/L Na2CO3) to assess the subsequent production of the high-value product, sulfoquinovosyl diacylglycerol (SQDG). After 25 days of growth, the reactors were composed of primarily Oscillatoria growth. All four reactors exhibited a trend of increasing biomass and alkalinity with time, and an initial increase then decrease in pH. The total inorganic carbon (TIC) in all reactors exhibited a mirrored, opposite trend …


A Three-Dimensional Hydro-Environmental Model Of Dublin Bay, Zeinab Bedri, Michael Buen, Aodh Dowley Aug 2011

A Three-Dimensional Hydro-Environmental Model Of Dublin Bay, Zeinab Bedri, Michael Buen, Aodh Dowley

Articles

This paper compares a 3-dimensional hydro-ecological model with a 2-dimensional model simulating the distribution and fate of Escherichia Coli (E.Coli) discharges from a sewage treatment plant discharging into Dublin Bay, Ireland. Before being discharged, the effluent from the sewage treatment plant is mixed with cooling water from a thermal generation plant resulting in a warm buoyant sewage plume that can be 7 − 9oC higher than the ambient water in the Bay. The mixing of the stratified plume is complicated by the tidal currents which transport the plume into and out of the estuary. These processes have a direct impact …


Application Of Shredded-Tire Biofilter And Membrane Bioreactor For Greywater Reclamation, Meng Hu Aug 2011

Application Of Shredded-Tire Biofilter And Membrane Bioreactor For Greywater Reclamation, Meng Hu

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Water scarcity is a pressing global issue. Greywater (GW) reclamation is a viable option to reduce freshwater demand. The objectives of this work were to: a) evaluate the feasibility of the combination of shredded tire biofilter (STB) technology and membrane bioreactor (MBR) technology in GW reclamation; b) study the effects of various parameters on STB performance; and c) understand the fouling mechanisms to lower the energy consumption in MBRs. Bench-scale STBs and MBRs (flat-sheet membranes) were constructed to address the first two objectives, while an independent membrane (hollow-fiber membranes) fouling experiment was designed for the third objective.

It was found …


Contaminant Mass Transfer During Boiling In Fractured Geologic Media, Fei Chen Aug 2011

Contaminant Mass Transfer During Boiling In Fractured Geologic Media, Fei Chen

All Dissertations

Remediation of fractured geologic media contaminated with chlorinated volatile organic compounds that diffuse into the matrix is challenging using isothermal methods. Due to the low permeability of the matrix material and uncertainty of fracture networks, it is difficult to flush the system with any type of fluid or deliver remediation agents into the matrix. However, thermal methods have some promises. When the matrix is heated above water boiling temperature, depressurization in the fractures may trigger water boiling in the matrix, which, as a result, generates a large volumetric steam flow toward adjacent fractures, stripping the adsorbed or dissolved volatile contaminants …


Applied And Mechanistic Studies Of Microbial 17beta-Estradiol Degradation, Zhongtian Li Jul 2011

Applied And Mechanistic Studies Of Microbial 17beta-Estradiol Degradation, Zhongtian Li

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The presence of natural estrogens, a class of endocrine disrupting compounds, in water has caused increasing concerns over their adverse impacts on the health of aquatic eco-systems and human beings. In this study, adsorption characteristics of two natural estrogens, 17β-estradiol (E2) and estrone (E1), on granular activated carbon (GAC) were investigated in isotherm tests and in a GAC column. The GAC column was then converted to a biologically active carbon (BAC) column and the removal efficiency of E2 and its primary biodegradation intermediate E1 were monitored. During BAC operation, the impacts of various reactor operation parameters, such as the carbon …


Do Wind Turbines Affect Weather Conditions?: A Case Study In Indiana, Meghan F. Henschen, Brittany Herrholtz, Lacey Rhudy, Kathryn Demchak, Brian Doogs, Joshua Holland, Erik Larson, Johnny Martin, Matthew Rudkin Jul 2011

Do Wind Turbines Affect Weather Conditions?: A Case Study In Indiana, Meghan F. Henschen, Brittany Herrholtz, Lacey Rhudy, Kathryn Demchak, Brian Doogs, Joshua Holland, Erik Larson, Johnny Martin, Matthew Rudkin

The Journal of Purdue Undergraduate Research

Wind turbines are becoming increasingly widespread in the United States as the world looks for cleaner sources of energy. Scientists, policymakers, and citizens have strong opinions regarding the positive and negative effects of wind energy projects, and there is a great deal of misinformation about wind energy circulating on the Web and other media sources. The purpose of this study is to gain a better understanding of how the rotation of hundreds of turbines can influence local weather conditions within a wind farm and in the surrounding areas. This experiment measures temperature, atmospheric pressure, wind speed, wind direction, relative humidity, …


Development Of Sstreamflow Projections Under Changing Climate Conditions Over Colorado River Basin Headwaters, W. P. Miller, Thomas C. Piechota, S. Gangopadhyay, T. Pruitt Jul 2011

Development Of Sstreamflow Projections Under Changing Climate Conditions Over Colorado River Basin Headwaters, W. P. Miller, Thomas C. Piechota, S. Gangopadhyay, T. Pruitt

Civil and Environmental Engineering and Construction Faculty Research

The current drought over the Colorado River Basin has raised concerns that the US Department of the Interior, Bureau of Reclamation (Reclamation) may impose water shortages over the lower portion of the basin for the first time in history. The guidelines that determine levels of shortage are affected by relatively short-term (3 to 7 month) forecasts determined by the Colorado Basin River Forecast Center (CBRFC) using the National Weather Service (NWS) River Forecasting System (RFS) hydrologic model. While these forecasts by the CBRFC are useful, water managers within the basin are interested in long-term projections of streamflow, particularly under changing …


Possibility Of Consolidated Wetland Mitigation In A Multi-Layered Legislated State, Juan P. Correa Jul 2011

Possibility Of Consolidated Wetland Mitigation In A Multi-Layered Legislated State, Juan P. Correa

Master's Theses

No abstract provided.


Fourier Finite Element Analysis Of Laterally Loaded Piles In Elastic Media Internal Geotechnical Report 2011-1, William Higgins, Dipanjan Basu Jul 2011

Fourier Finite Element Analysis Of Laterally Loaded Piles In Elastic Media Internal Geotechnical Report 2011-1, William Higgins, Dipanjan Basu

Technical Reports

Laterally loaded piles are analyzed using the Fourier finite element method. Pile response was observed to be a function of the relative stiffness of pile and soil and of the pile slenderness ratio. The analysis is mostly performed for piles embedded in elastic soil with constant and linearly varying modulus although the pile response in two-layer soil profiles is also investigated. Equations describing pile head deflection, rotation and maximum bending moment are proposed for flexible long piles and stubby rigid piles. The design equations were developed after plotting the pile responses as functions of pile-soil stiffness ratio and pile slenderness …


Sustainability In Geotechnical Engineering Internal Geotechnical Report 2011-2, Aditi Misra, Dipanjan Basu Jul 2011

Sustainability In Geotechnical Engineering Internal Geotechnical Report 2011-2, Aditi Misra, Dipanjan Basu

Technical Reports

The built environment serves as a dynamic interface through which the human society and the ecosystem interact and influence each other. Understanding this interdependence is key to understanding sustainability as it applies to civil engineering. There is a growing consensus that delivering a sustainable built environment starts with incorporating sustainability thoughts at the planning and design stages of a project. Geotechnical engineering is the most resource intensive of all the civil engineering disciplines and can significantly influence the sustainability of infrastructure development because of its early position in the construction process. In this report, a review is made of the …


Nitrogen Mass Balance In A High Rate Algal Pond, Kevin Jones Jul 2011

Nitrogen Mass Balance In A High Rate Algal Pond, Kevin Jones

Biomedical Engineering

The objective of the study described herein was to perform a mass balance on nitrogen in four small high rate algal ponds (HRAPs) in order to determine the fate of the nitrogen. The total percentage of nitrogen lost via ammonia volatilization was calculated via the mass balance.


Unintended Consequences: Potential Downsides Of The Air Force's Conversion To Biofuels, Mark N. Goltz, Charles A. Bleckmann, Charles M. Mackay, Khai Vuong, Jerrod P. Mccomb Jul 2011

Unintended Consequences: Potential Downsides Of The Air Force's Conversion To Biofuels, Mark N. Goltz, Charles A. Bleckmann, Charles M. Mackay, Khai Vuong, Jerrod P. Mccomb

Faculty Publications

The desire to reduce US dependence on foreign energy, ongoing environmental concerns, and the rising cost of petroleum have sparked significant development of greener alternative and renewable energy sources such as alcohol-based biofuels. To address these issues, the Department of Defense DOD has moved to diminish its reliance on petroleum for fueling aircraft and ground equipment. The US Air Force, in alignment with DOD objectives, has initiated several goals for reducing its use of energy: (1) decrease the use of petroleum-based fuel by 2 percent annually for the vehicle fleet, (2) increase the use of alternative fuel in motor vehicles …


Identifying Changes In Climatic Trends And The Fingerprints Of Landuse And Landcover Changes In The High Plains Of The Usa, Denis Mutiibwa Jul 2011

Identifying Changes In Climatic Trends And The Fingerprints Of Landuse And Landcover Changes In The High Plains Of The Usa, Denis Mutiibwa

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Human activities such as conversion of natural ecosystem to croplands and urban-centers, deforestation and afforestation impact biophysical properties of land surface such as albedo, energy balance, and surface roughness. Alterations in these properties affect the heat and moisture exchanges between the land surface and atmospheric boundary layer. The objectives of this research were; (i) to quantitatively identify the High plains’ regional climate change in temperatures over the period 1895 to 2006, (ii) detect the signatures of anthropogenic forcing of LULC changes on the regional climate change of the High Plains, and (iii) examine the trends in evolving regional latent heat …


Using Laser Scanning Cytometry To Investigate The Transport Of Nano-Scale Particles In Porous Media, Ryan May Jul 2011

Using Laser Scanning Cytometry To Investigate The Transport Of Nano-Scale Particles In Porous Media, Ryan May

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The increased production of nanomaterials in recent years has been unprecedented. Given their potential toxicity, understanding the mechanisms controlling the transport of nanoparticles in the subsurface is important. In this study, a technique was developed for using a Laser Scanning Cytometer (LSC) to visualize and quantify the stable attachment of nano-scale particles. Experiments using three different size particles, 510 nm, 210 nm and 57 nm, in conjunction with a flow cell system containing saturated glass beads under varied injection duration, solution chemistry, Darcy velocity and solids content were performed. A technique for using the LSC data to develop spatial distributions …


A Review Of Zero Discharge Wastewater Treatment Systems Using Reed Willow Bed Combinations In Ireland, Sean O'Hogain, Liam Mccarton, Anna Reid, John Turner Jun 2011

A Review Of Zero Discharge Wastewater Treatment Systems Using Reed Willow Bed Combinations In Ireland, Sean O'Hogain, Liam Mccarton, Anna Reid, John Turner

Articles

The concept of a reed willow bed combination has the potential to achieve a zero discharge wastewater treatment system. This paper will present results from a two year study to monitor the performance of a reed willow bed facility at Lynches Lane, Co. Dublin, Ireland. Outline design specifications for the facility will be presented. Monitoring results for a two year period including influent and effluent parameters, rainfall, potential evapotranspiration, and soil classification will be presented and discussed. During the two year monitoring period the system achieved a zero discharge. This paper will discuss the potential widespread application of similar systems …


Validated Trnsys Model For Forced Circulation Solar Water Heating Systems With Flat Plate And Heat Pipe Evacuated Tube Collectors, Lacour Ayompe, Aidan Duffy, Sarah Mccormack, Michael Conlon Jun 2011

Validated Trnsys Model For Forced Circulation Solar Water Heating Systems With Flat Plate And Heat Pipe Evacuated Tube Collectors, Lacour Ayompe, Aidan Duffy, Sarah Mccormack, Michael Conlon

Articles

This paper presents a validated TRNSYS model for forced circulation solar water heating systems used in temperate climates. The systems consist of two flat plate collectors (FPC) and a heat pipe evacuated tube collector (ETC) as well as identical auxiliary components. The systems were fitted with an automated unit that controlled the immersion heaters and hot water demand profile to mimic hot water usage in a typical European domestic dwelling. The main component of the TRNSYS model was the Type 73 FPC or Type 538 ETC. A comparison of modelled and measured data resulted in percentage mean absolute errors for …


Anaerobic Co-Digestion Of Microalgae With Food Waste And Wastewater Sludge, Ruth E. Spierling Jun 2011

Anaerobic Co-Digestion Of Microalgae With Food Waste And Wastewater Sludge, Ruth E. Spierling

Master's Theses

This research sought to optimize anaerobic co-digestion of microalgae biomass harvested from a wastewater treatment pond facility with locally-available wastes.  The goal was to produce high methane yields and stable digestion without the need for supplemental alkalinity addition.  A key research question was if algae digestion could be improved via the synergistic effects of co-digestion.  Cell disruption to increase digestibility was not pursued due to its relatively high mechanical complexity and high energy use.  For the wastewater treatment ponds studied, the most practical co-substrates identified were municipal wastewater sludge and food waste (sorted organic municipal waste).  Although wastewater sludge does …


Magnetic Seeding Aggregation To Enhance The Removal Efficiency Of Tio2 Nanoparticles From Water, Ashish Dhananjay Borgaonkar May 2011

Magnetic Seeding Aggregation To Enhance The Removal Efficiency Of Tio2 Nanoparticles From Water, Ashish Dhananjay Borgaonkar

Dissertations

Engineered nanoparticles, such as titanium dioxide (TiO2), are important building blocks for the evolution of nanotechnology in industries and commercial products. Ever so increasing use of the engineered nanoparticles is bound to result in a substantial fraction of these nanoparticles ending up in wastewater; or surface water and groundwater, which are sources of intake for drinking water treatment. Removal of these engineered nanoparticles in wastewater and drinking water treatment processes is a very important step towards the protection of environmental and public health as well as protecting water treatment units from fouling and other issues.

Experimental studies showed …


A Study Of The New York / New Jersey Coastal Water : Bio-Optical Characteristics Of The Harbor Estuary And The Effects Of Heavy Metals On Brown Tide Alga Of The Bight, Bin Wang May 2011

A Study Of The New York / New Jersey Coastal Water : Bio-Optical Characteristics Of The Harbor Estuary And The Effects Of Heavy Metals On Brown Tide Alga Of The Bight, Bin Wang

Dissertations

The New York / New Jersey (NY/NJ) coastal area is one of the most productive regions around the world and a major natural and scenic resource for New York and New Jersey. As a result of excessive nutrient loading in the water, algal blooms have been observed since 1950’s. The NY/NJ coastal area includes the NY/NJ Bight and the NY/NJ Harbor Estuary, and in the former, brown tides (Aureococcus anophagefferens) were first observed in 1985 becoming a more serious water quality problem over the last 25 years. The influence of micronutrients, namely trace metals, on A. anophagefferens that are widespread …


College Of Engineering Senior Design Competition Spring 2011, University Of Nevada, Las Vegas May 2011

College Of Engineering Senior Design Competition Spring 2011, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge.

The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …


College Of Engineering Senior Design Competition Fall 2011, University Of Nevada, Las Vegas May 2011

College Of Engineering Senior Design Competition Fall 2011, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge. The senior design competition helps focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects on …


How Much Do U.S. University Students Know, And Want To Know, About Sustainability And Green Building? The Findings Of A Survey, And Possible Implications For General Elective Curricula., Jeremy R. Farner May 2011

How Much Do U.S. University Students Know, And Want To Know, About Sustainability And Green Building? The Findings Of A Survey, And Possible Implications For General Elective Curricula., Jeremy R. Farner

Purdue Polytechnic Masters Theses

Using the survey approach, this investigation examined the attitudes and interest of college students at two universities in different geographic locations within the United States.  Approximately 24,000 students from all disciplines and majors at Weber State University (WSU) in Utah, and 4,000 at Purdue University in Indiana, were invited to participate in a study to determine current knowledge, familiarity, and interest in topics within the sustainability and Green Building educational arena. The goal of this study was to determine what students already know, would like to know, and how much interest there would be in developing …