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2011

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Articles 211 - 240 of 934

Full-Text Articles in Civil and Environmental Engineering

Structural Health Monitoring Of Historic Masonry Monuments, Saurabh Prabhu Aug 2011

Structural Health Monitoring Of Historic Masonry Monuments, Saurabh Prabhu

All Theses

Structural Health Monitoring (SHM) is a well-accepted diagnostic technique being used to evaluate modern structures. This method involves monitoring the vibration response of a structure to detect changes in its structural state. The primary intention of this thesis is to address two practical and technical difficulties encountered in deploying SHM on historic masonry monuments: (i) the selection of suitable low dimensional vibration response features that are highly sensitive to the presence and extent of damage, while having low sensitivity to extraneous noise and (ii) the selection of optimal sensor locations for efficient system identification applied to Gothic Cathedrals. Both of …


Retrofit Solutions For Sealed Pervious Concrete Pavements, Gregory Bunting Aug 2011

Retrofit Solutions For Sealed Pervious Concrete Pavements, Gregory Bunting

All Theses

The goal of this research was to design, implement, and evaluate several retrofit solutions for sealed pervious concrete. Properly functioning pervious concrete pavements allow water to drain through the structure, eliminating the need for traditional drainage infrastructure. A recent study of South Carolina porous pavements (Putman 2010) revealed that some pervious concrete pavements are not properly draining, either because of sealing at the surface. Sealed pavements are generally a result of construction processes, and sealed pavements cannot be fixed with sediment removal techniques such as vacuuming and pressure washing. This study investigates a technique to increase infiltration of sealed pervious …


Phytoforensics, Dendrochemistry, And Phytoscreening: New Green Tools For Delineating Contaminants From Past And Present, Joel Gerard Burken, Don A. Vroblesky, Jean Christophe Balouet Aug 2011

Phytoforensics, Dendrochemistry, And Phytoscreening: New Green Tools For Delineating Contaminants From Past And Present, Joel Gerard Burken, Don A. Vroblesky, Jean Christophe Balouet

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

As Plants Evolved to Be Extremely Proficient in Mass Transfer with their Surroundings and Survive as Earth's Dominant Biomass, They Also Accumulate and Store Some Contaminants from Surroundings, Acting as Passive Samplers. Novel Applications and Analytical Methods Have Been Utilized to Gain Information About a Wide Range of Contaminants in the Biosphere Soil, Water, and Air, with Information Available on Both Past (Dendrochemistry) and Present (Phytoscreening). Collectively These Sampling Approaches Provide Rapid, Cheap, Ecologically Friendly, and overall "Green" Tools Termed "Phytoforensics". © 2011 American Chemical Society.


Effectiveness Study Of Non-Nuclear Gauge For Hot Mix Asphalt (Hma) Pavement Construction, Ziqing Zhuang Aug 2011

Effectiveness Study Of Non-Nuclear Gauge For Hot Mix Asphalt (Hma) Pavement Construction, Ziqing Zhuang

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Density is an important measure for hot-mix asphalt (HMA) pavement quality control. Traditionally, the nuclear gauge method is widely used in pavement density testing. However, some disadvantages of nuclear gauges (such as the handling, storage, and transportation of radioactive materials) have created the need of non-nuclear technology. This thesis evaluated the Pavement Quality Indicator (PQI) model 301, which was promised to be more efficient than the nuclear method. The PQI utilizes many electrical impedance principles by using the current going through the pavement to determine its density and moisture content. Test data were collected in the field during pavements, and …


Effectiveness Study On Temporary Pavement Marking Removals Methods, Koudous Kabassi Aug 2011

Effectiveness Study On Temporary Pavement Marking Removals Methods, Koudous Kabassi

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

This study was conducted to identify effective temporary marking removal methods and procedures on concrete and asphalt pavements. Pavement markings provide guidance to road travelers and can lead to accidents when not properly removed. Current state guidelines on removal do not provide clear and objective methods of measurement. After testing the most common removal methods, this research concluded that removing markings by chemical was not only cost and results-oriented effective compared to other methods, but it was also safe to the environment and road users. Finally, a baseline of measurements was developed for this project, along with the feasibility of …


Capturing The Lost Phosphorus, Bruce E. Rittmann, Brooke K. Mayer, Paul Westerhoff, Mark Edwards Aug 2011

Capturing The Lost Phosphorus, Bruce E. Rittmann, Brooke K. Mayer, Paul Westerhoff, Mark Edwards

Civil and Environmental Engineering Faculty Research and Publications

Minable phosphorus (P) reserves are being depleted and will need to be replaced by recovering P that currently is lost from the agricultural system, causing water-quality problems. The largest two flows of lost P are in agricultural runoff and erosion (∼46% of mined P globally) and animal wastes (∼40%). These flows are quite distinct. Runoff has a very high volumetric flow rate, but a low P concentration; animal wastes have low flow rates, but a high P concentration together with a high concentration of organic material. Recovering the lost P in animal wastes is technically and economically more tractable, and …


Resonant Microcantilevers For The Determination Of The Loss Modulus Of Thin Polymer Films, Cedric Ayela, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour Aug 2011

Resonant Microcantilevers For The Determination Of The Loss Modulus Of Thin Polymer Films, Cedric Ayela, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour

Civil and Environmental Engineering Faculty Research and Publications

The increasing interest in polymer materials creates the need for accurate tools to characterize their mechanical properties. Due to energy dissipation in polymers during deformation, these materials exhibit viscoelastic behavior. Accurate determination of these viscoelastic properties and, more specifically, viscous losses, remains challenging and mainly unknown for thin polymer films. In this paper, a straightforward method to determine the loss modulus of organic materials using resonating microcantilevers has been developed. The extracted results for polyisobutylene show the variation of viscous losses over a large range of frequencies (7-350 kHz).


Streambank Erosion And Instability Induced By Groundwater Seepage, Taber L. Midgley, Garey A. Fox, Glenn V. Wilson, Derek M. Heeren, Andrew Simon, Eddy J. Langendoen Aug 2011

Streambank Erosion And Instability Induced By Groundwater Seepage, Taber L. Midgley, Garey A. Fox, Glenn V. Wilson, Derek M. Heeren, Andrew Simon, Eddy J. Langendoen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Excessive sediment is one of the most common surface water pollutants. It diminishes water quality and destroys aquatic habitat. Streambank erosion is known to be a major source of sediment in streams and rivers, contributing as much as 80% of the total sediment load in some watersheds. Little work has been done to study the effects of seepage on streambank erosion and failure. Prior research, primarily in the laboratory under well-defined and controlled conditions, has examined seepage as a mechanism for bank erosion, but more needs to be done to validate conclusions derived from the laboratory with field data. This …


Bayesian Data-Driven Models For Irrigation Water Management, Alfonso F. Torres-Rua Aug 2011

Bayesian Data-Driven Models For Irrigation Water Management, Alfonso F. Torres-Rua

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A crucial decision in the real-time management of today’s irrigation systems involves the coordination of diversions and delivery of water to croplands. Since most irrigation systems experience significant lags between when water is diverted and when it should be delivered, an important technical innovation in the next few years will involve improvements in short-term irrigation demand forecasting.

The main objective of the researches presented was the development of these critically important models: (1) potential evapotranspiration forecasting; (2) hydraulic model error correction; and (3) estimation of aggregate water demands. These tools are based on statistical machine learning or data-driven modeling. These, …


Structural Identification And Damage Identification Using Output-Only Vibration Measurements, Shutao Xing Aug 2011

Structural Identification And Damage Identification Using Output-Only Vibration Measurements, Shutao Xing

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation studied the structural identification and damage detection of civil engineering structures. Several issues regarding structural health monitoring were addressed.

The data-driven subspace identification algorithm was investigated for modal identification of bridges using output-only data. This algorithm was tested through a numerical truss bridge with abrupt damage as well as a real concrete highway bridge with actual measurements. Stabilization diagrams were used to analyze the identified results and determine the modal characteristics. The identification results showed that this identification method is quite effective and accurate.

The influence of temperature fluctuation on the frequencies of a highway concrete bridge was …


Sensitivity Analysis Of Load Distribution In Light-Framed Wood Roof System Due To Typical Modeling Parameters, Ranjith Shivarudrappa Aug 2011

Sensitivity Analysis Of Load Distribution In Light-Framed Wood Roof System Due To Typical Modeling Parameters, Ranjith Shivarudrappa

All Theses

Since failure of roof systems in past high wind events have demonstrated the consequences of not maintaining a continuous load path from the roof to the foundation, many studies have been conducted to better understand this load path, including how loads are distributed in the system. The present study looks to add to the current knowledge of the vertical load path by focusing on uplift loads and by considering the sensitivity of different modeling parameters. This is done by developing and assessing load influence coefficients for various roof-to-wall (RTW) connections. An analytical model of a light-framed wood structure using finite …


Evaluation Of Warm Mix Open Graded Friction Course Mixtures, James Wurst Aug 2011

Evaluation Of Warm Mix Open Graded Friction Course Mixtures, James Wurst

All Theses

The goal of this study was to evaluate EvothermTM (a chemical package) and foaming (a water-injection method) warm mix asphalt (WMA) technologies to determine their effectiveness in producing high quality open graded friction course (OGFC) mixes. Specifically, this study focused on the effect of the removal of stabilizing additives (fibers and polymers) on the optimum binder content and performance of WMA OGFC mixtures. By focusing on additive removal, this study attempted to evaluate practical production concerns and the possible benefits of WMA technologies combined with OGFC.
The EvothermTM WMA and foaming WMA mixes were compared to traditional HMA OGFC by …


Behavior Of The Next-D Beam Shear Key: A Finite Element Approach, Armando Flores Aug 2011

Behavior Of The Next-D Beam Shear Key: A Finite Element Approach, Armando Flores

All Theses

State Departments of Transportation have been using adjacent precast bridges for many years. A vital component of this type of bridges is the connection between the members, which is typically done with a grouted shear key. Shear keys have changed through time to adapt to the requirements of bridge design. An assessment of the Northeast Extreme Tee with integral deck (NEXT-D) was performed for the SCDOT as a development possibility for short span bridges. This research focuses on the finite element analysis study of the NEXT-D's specific shear key configuration.
A review of shear key configurations used by different DOTs …


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 …


An Experimental And Computational Study Of Windborne Debris In Severe Storms, Arash Karimpour Aug 2011

An Experimental And Computational Study Of Windborne Debris In Severe Storms, Arash Karimpour

All Dissertations

Abstract
This research focuses on an experimental and theoretical investigation of windborne debris emanating from loose gravel on built-up roofs. During severe storms, windborne debris can cause considerable physical harm and property damage. One of the major sources of flying debris in large commercial areas is loose gravel on built-up roofs. Such loose gravel can be responsible loss of life and significant property damage. Despite the high risk of windborne debris, their flight mechanics are poorly understood. To better understand windborne debris flight, a series of experiments were conducted in the Clemson University Boundary Layer Wind Tunnel. These experiments were …


The Effects Of Fundamental Mixture Parameters On Hot-Mix Asphalt Performance Properties, Wenbin Zhao Aug 2011

The Effects Of Fundamental Mixture Parameters On Hot-Mix Asphalt Performance Properties, Wenbin Zhao

All Dissertations

Asphalt pavements are composed of three components: aggregate, asphalt binder, and air. In the process of plant production and on-site construction, the construction quality can vary in the three component and the variability can further affect a pavement's future performance.. This research identifies aggregate gradation, binder content, and air voids content as the fundamental parameters. Understanding the fundamental parameters' influence on the HMA mixture's performance properties can provide valuable information on how to improve the current quality insurance practice. The objective of this study is to conduct well-controlled experiments to investigate how mix gradation, air voids and small range binder …


Social Sustainability Considerations During Planning And Design: A Framework Of Processes For Construction Projects, Rodolfo Valdes Vasquez Aug 2011

Social Sustainability Considerations During Planning And Design: A Framework Of Processes For Construction Projects, Rodolfo Valdes Vasquez

All Dissertations

With increased awareness of issues such as global resource shortages and climate change, sustainability efforts are becoming more common in the construction industry. While these efforts often consider economic and environmental factors, a truly sustainable construction project also needs to include such social considerations as its impact on the surrounding community and the safety, health, and education of the workforce. For the construction industry, social sustainability requires integrating processes for improving safety, health and well-being over the project life cycle. However, an empirical and comprehensive framework defining these social sustainability processes in construction projects has yet to be clearly delineated. …


Investigation Into The Role Of Airfield Pavement Deicer In Concrete Pavement Deterioration, David Wingard Aug 2011

Investigation Into The Role Of Airfield Pavement Deicer In Concrete Pavement Deterioration, David Wingard

All Dissertations

Premature deterioration of concrete due to materials-related distresses has been observed with increased frequency in airfield pavements across the United States in the past two decades. The use of a new breed of deicing chemicals based on alkali-acetates and alkali-formates, starting in the early 1990s, has been suspected to be one of the significant reasons for the increase in the observed deterioration. Previous laboratory-based studies have found that the early-age deterioration in concrete is associated with exposure to deicers causing acceleration of the Alkali Silica Reaction (ASR) deterioration mechanism and consequent failure. However, no systematic forensic studies on the impact …


A Computationally Efficient Ground-Motion Selection Algorithm For Matching A Target Response Spectrum Mean And Variance, Nirmal Jayaram, Ting Lin, Jack W. Baker Aug 2011

A Computationally Efficient Ground-Motion Selection Algorithm For Matching A Target Response Spectrum Mean And Variance, Nirmal Jayaram, Ting Lin, Jack W. Baker

Civil and Environmental Engineering Faculty Research and Publications

Dynamic structural analysis often requires the selection of input ground motions with a target mean response spectrum. The variance of the target response spectrum is usually ignored or accounted for in an ad hoc manner, which can bias the structural response estimates. This manuscript proposes a computationally efficient and theoretically consistent algorithm to select ground motions that match the target response spectrum mean and variance. The selection algorithm probabilistically generates multiple response spectra from a target distribution, and then selects recorded ground motions whose response spectra individually match the simulated response spectra. A greedy optimization technique further improves the match …


Performance Rating Of De-Icing Chemicals For Winter Operations, Barbara M. Gerbino-Bevins Aug 2011

Performance Rating Of De-Icing Chemicals For Winter Operations, Barbara M. Gerbino-Bevins

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

The cost of deicing chemicals is a significant part of the Nebraska Department of Road's winter maintenance budget. Many products are available for use in highway and bridge deicing and new products are introduced each year. The objectives of this research are to develop a laboratory test to evaluate the performance of chemical deicers, to investigate national, state, and local standards, and to develop best maintenance practices to optimize the use of chemical deicers.

This research project consists of two phases:

Phase 1: conduct a literature survey to find data from existing laboratory tests used to evaluate deicer performance.

Phase …


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 …


Estimating Yield Of Irrigated Potatoes Using Aerial And Satellite Remote Sensing, Saravanan Sivarajan Aug 2011

Estimating Yield Of Irrigated Potatoes Using Aerial And Satellite Remote Sensing, Saravanan Sivarajan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Multispectral aerial and satellite remote sensing plays a major role in crop yield prediction due to its ability to detect crop growth conditions on spatial and temporal scales in a cost effective manner. Many empirical relationships have been established in the past between spectral vegetation indices and leaf area index, fractional ground cover, and crop growth rates for different crops through ground sampling. Remote sensing-based vegetation index (VI) yield models using airborne and satellite data have been developed only for grain crops like barley, corn, wheat, and sorghum. So it becomes important to validate and extend the VI-based model for …


Comparison Of Design-Build And Design-Bid-Build Performance Of Public University Projects, James David Fernane Aug 2011

Comparison Of Design-Build And Design-Bid-Build Performance Of Public University Projects, James David Fernane

UNLV Theses, Dissertations, Professional Papers, and Capstones

With an unsure market and scarce work, owners across the United States, especially universities, are finding themselves in situations where they are unable to complete their projects within cost and schedule using the traditional delivery method: Design-Bid-Build (DBB). Under the DBB project delivery method, many competent contractors are electing to send low bids on projects just to keep work on their books, with plans to receive change orders once the project is underway; this practice is leading to cost and schedule overruns. Public universities across the United States are beginning to elect to use Design-Build (DB) as an alternate project …


Groundwater Contamination Potential In Northern Nevada From Mining, Associated Communities, And Agriculture As Forecasted By Two Vulnerability Methods, John L. Swatzell Aug 2011

Groundwater Contamination Potential In Northern Nevada From Mining, Associated Communities, And Agriculture As Forecasted By Two Vulnerability Methods, John L. Swatzell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Two methodologies, DRASTIC and the NDEP method, were used to compare the groundwater vulnerability of mining, associated towns, and agricultural areas in northern Nevada. The DRASTIC and NDEP methods were compared to determine which method produces a more accurate depiction of vulnerability. Vulnerability maps were created using the United States Environmental Protection Agency's (USEPA) DRASTIC and Nevada Department of Environmental Protection (NDEP) methodologies. The DRASTIC map uses seven aspect layers of geologic and hydrologic information with assigned values and weights that are applied to a mathematical equation. The NDEP method uses field data collection for potential contaminant sources and well …


Seismic Characterization Of Select Engineered Nanoparticles In Essentially Saturated Glass Beads, Mohamed Nihad Rajabdeen Aug 2011

Seismic Characterization Of Select Engineered Nanoparticles In Essentially Saturated Glass Beads, Mohamed Nihad Rajabdeen

UNLV Theses, Dissertations, Professional Papers, and Capstones

A laboratory testing apparatus was developed for the study of seismic body wave propagation through nanoparticles dispersed in pore fluid that is essentially saturating glass beads. First, the responses of water-saturated glass bead specimens were studied to establish baseline signatures. Then the seismic responses in the presence of engineered nanoparticles of various concentrations dispersed in the pore fluid of the specimen chamber were studied to observe variances from baseline.

The testing apparatus incorporates piezoceramic bender elements to actuate and receive seismic body waves through a cylindrical column filled with glass beads and back-saturated at ambient pressure with liquid. The system …


Assessing The Surface Energy Balance Components In The Snake River Basin, W Thilini Ajanthik Jaksa Aug 2011

Assessing The Surface Energy Balance Components In The Snake River Basin, W Thilini Ajanthik Jaksa

Boise State University Theses and Dissertations

This study investigated the interaction of land-surface processes and vegetation in both natural ecosystems and irrigated agricultural lands in a semiarid region using the Noah land surface model (LSM) in combination with the Weather Research and Forecasting (WRF) Model. This study was conducted in the semiarid Snake River plains of south central Idaho comprising of both natural vegetation and agricultural lands. This area is characterized by warm, dry summers with irrigation being the main moisture source during the growing season. In order to properly represent the conditions of agricultural lands and also to investigate the effects of irrigation on land-surface …


Recycling Waste Latex Paint In Overlays, Rigid Pavements, And Pervious Concrete, Oscar Inez Quiroz Aug 2011

Recycling Waste Latex Paint In Overlays, Rigid Pavements, And Pervious Concrete, Oscar Inez Quiroz

UNLV Theses, Dissertations, Professional Papers, and Capstones

With over 16 million gallons of latex paint (WLP) being disposed every year it is the largest by volume, liquid hazardous waste in the United States. WLP is difficult to recycle and hazardous to the environment due to the volatile organic compounds it contains. Several methods exist for disposing WLP including paint swaps, combustion, drying and discarding in a landfill, and by placing pigments in cement. Many communities are moving to dispose WLP by drying and placing in a landfill due to the reduced cost. However, this is the least preferred technique for the environment because it creates a need …


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 …


Roadside Grading Guidance, Kevin D. Schrum Jul 2011

Roadside Grading Guidance, Kevin D. Schrum

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

Provisions for the design of roadside foreslopes are not readily available, and as a result, engineering judgment is often employed. Unfortunately, this can lead to inconsistent designs, where, inevitably, some designs will be too costly and other designs will be too dangerous. Therefore, a design guide was created to lend consistency to the design of these foreslopes while maintaining the most economical and safe design.

This design guide was prepared after conducting a benefit-cost analysis using the Roadside Safety Analysis Program (RSAP). A large test matrix was developed in an attempt to simulate the most possible scenarios, leaving interpolation to …


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, …