Civil and Environmental Engineering Commons^™

Navigating The Academic Job Search For Environmental Engineers: Guidance For Job Seekers And Mentors, David A. Ladner, Stephanie C. Bolyard, Defne Apul, Andrew J. Whelton

Publications

Students and postdoctoral associates interested in tenure-track environmental engineering positions have limited resources to aid them. The Student Services Committee (SSC) of the Association of Environmental Engineering and Science Professors (AEESP) organized a workshop to fill some of the need. Newly hired faculty and experienced search committee and department chairs shared information on how to create competitive applications. Students and postdoctoral associates were also provided with individualized feedback on their faculty application packages. Survey data were collected for all participants, and these data are presented in this paper along with tips shared during the workshop and information collected from the …

Analysis Of Internet Visitors On Educational Websites, Georgia Romig, Byungik Chang, Kenneth Leitch, Aaron Hunt

Civil Engineering Faculty Publications

This study examines usage patterns of educational websites that employ databases, wikis, and general resources for information sharing and dissemination. To gather data about website usage, a quantitative survey was sent out to students and to the users of an existing educational website. Additionally, participants provided data on learning preferences and practices. Findings from the survey show that users visit an education website for finding information and getting connected to a community. The survey results also show that while communicating information should remain a top priority, educational web sites will need to adapt to an increasing desire for interpersonal communication …

Dynamics And Dislodgment From Pore Constrictions Of A Trapped Nonwetting Droplet Stimulated By Seismic Waves, Wen Deng, M. Bayani Cardenas

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Seismic waves affect fluid flow and transport processes in porous media. Therefore, quantitative understanding of the role of seismic waves in subsurface hydrodynamics is important for the development of practical applications and prediction of natural phenomena. We present a theoretical fluid dynamics model to describe how low-frequency elastic waves mobilize isolated droplets trapped in pores by capillary resistance. The ability of the theoretical model to predict the critical mobilization amplitudes (A_c) and the displacement dynamics of the nonwetting droplet are validated against computational fluid dynamics (CFD) simulations. Our theory has the advantage of rapid calculation of A_{c …}

Photocatalytic Degradation Of Air Emissions From Municipal Solid Waste Landfills, Mita S. Upadhyay, Melanie L. Sattler

Civil Engineering Faculty Publications - Archive

No abstract provided.

Weighing The Financial And Sustainable Benefits Of High Performance Structures In Seismically Active Regions, Alia Talina Barajas

Master's Theses

This thesis investigated the potential advantages and disadvantages of high performance structures by comparing the financial and environmental impacts of a performance based four-story office building to one designed to meet minimum code-level requirements.

To generate a comparison, the lateral system of a four-story structure utilizing buckling restrained braced frames was designed to meet code-level requirements per the American Society of Civil Engineers’ Minimum Design Loads for Buildings and Other Structures (ASCE 7-05) and again to meet the immediate occupancy criteria defined by ASCE 41-06 Seismic Rehabilitation of Existing Buildings. The following was then performed:

• Test the structural performance of …

Reliability-Based Topology Optimization Of Trusses With Stochastic Stiffness, Mehdi Jalalpour, James K. Guest, Takeru Igusa

Civil and Environmental Engineering Faculty Publications

A new method is proposed for reliability-based topology optimization of truss structures with random geometric imperfections and material variability. Such imperfections and variability, which may result from manufacturing processes, are assumed to be small in relation to the truss dimensions and mean material properties and normally distributed. Extensive numerical evidence suggests that the trusses, when optimized in terms of a displacement-based demand metric, are characterized by randomness in the stiffness that follow the Gumbel distribution. Based on this observation, it was possible to derive analytical expressions for the structural reliability, enabling the formulation of a computationally efficient single-loop reliability-based topology …

Evaluation Of Mechanically Stabilized Earth Walls For Bridge Ends In Kentucky; What Next?, Charlie Sun, Clark Graves

Kentucky Transportation Center Research Report

This report summarizes the nationwide survey results on MSE wall abutment status. Many of handy features on MSE Wall Abutment Inspection/Rating In KY web application are highlighted, and various graphical user interfaces of the web application are illustrated and described. The inspection/rating results for fifty-six (56) existing MSE wall abutments are presented and discussed.

Linear Programming Algorithm With Mixed Real-Integer Variables In Matlab Environments, Gelareh Bakhtyar

Civil & Environmental Engineering Theses & Dissertations

Efficient numerical procedures for solving general Linear Programming (LP) problems with mixed real-integer variables are developed in this work. The proposed algorithms employ the revised dual simplex with Branch and Bound (B&B) algorithms, with special procedures for limited search of subsequent branches. Computational time can be significantly reduced by incorporating the updated inverse formulas into the developed procedures. Both generic LP problems and deterministic pavement maintenance and rehabilitation (M&R) problems are used in this study to vaiidate the developed procedures. Medium to large-scale examples ( 11 pavement M&R) presented in this work have demonstrated that the developed numerical procedures consistently …

Ground Shock Resistance Of Mechanically Stabilized Earth Walls, Christopher Y. Tuan

Civil Engineering Faculty Publications

A simple analytical method has been developed that characterizes plane shock wave propagation through reinforced soil and the dynamic interaction between soil and retaining wall panels. The shock wave due to an explosion in the backfill was modeled as a velocity boundary condition at a standoff distance from the wall. The exact solution to this problem was obtained using the Laplace transform method. Full-scale explosive test data from 4.6-m high and 24-m wide reinforced soil walls were used to validate the analytical methodology. The accuracy of the analytical method has further been verified by finite element analysis. The method is …

Development Of A New Energy-Absorbing Roadside/Median Barrier System With Restorable Elastomer Cartridges, Ronald K. Faller, Dean L. Sicking, Karla A. Lechtenberg, Robert W. Bielenberg, Scott K. Rosenbaugh, James C. Holloway, John D. Reid, Jennifer D. Schmidt

Nebraska Department of Transportation: Research Reports

No abstract provided.

Observations Of Peak Strength Behavior In Csa Cement Mortars, Joshua V. Brien, Kevin R. Henke, Kamyar C. Mahboub

Civil Engineering Faculty Publications

The purpose of this study was to assess the mechanical property performance behavior of calcium sulfoaluminate (CSA) cement mortar when cured at ambient laboratory temperature of ~23°C (73°F) and constant 50% relative humidity for an extended period of time. Four CSA cement mortars were tested. Three CSA cement mortars contained equivalent mass amounts of calcium sulfate; whereas, the fourth mortar contained double the amount of calcium sulfate. The three CSA cement mortars containing constant mass amounts of calcium sulfate differed as the specific type of calcium sulfate varied across the three formulations—one mortar containing solely anhydrite, one mortar contained half …

Effects Of Hinged Dowel System On The Performance Of Concrete Pavement Joints, Alireza Zeinali, Kamyar C. Mahboub, Herbert F. Southgate

Civil Engineering Faculty Publications

Concrete joint failure is a major distress mode in rigid pavements. Improving the joint performance in concrete pavements could yield substantial savings in terms of reduced maintenance and rehabilitation costs. The newly developed Hinged Dowel System (HDS) is a means for transferring loads across the concrete pavement joints. The HDS was patented as a new invention by the United States Patent and Trademark Office, and it is envisioned that it could significantly reduce the potential for joint failure in concrete pavements. The HDS assembly comprises a number of dowel bars and a collective hinge provided at the mid-length of the …

Triclosan Enriches For Dehalococcoides-Like Chloroflexi In Anaerobic Soil At Environmentally Relevant Concentrations, Patrick J. Mcnamara, Mark J. Krzmarzick

Civil and Environmental Engineering Faculty Research and Publications

Triclosan is an antimicrobial agent that is discharged to soils with land-applied wastewater biosolids, is persistent under anaerobic conditions, and yet its impact on anaerobic microbial communities in soils is largely unknown. We hypothesized that triclosan enriches for Dehalococcoides-like Chloroflexi because these bacteria respire organochlorides and are likely less sensitive, relative to other bacteria, to the antimicrobial effects of triclosan. Triplicate anaerobic soil microcosms were seeded with agricultural soil, which was not previously exposed to triclosan, and were amended with 1 mg kg⁻¹ of triclosan. Triplicate control microcosms did not receive triclosan, and the experiment was run for …

Resonant Characteristics Of Rectangular Hammerhead Microcantilevers Vibrating Laterally In Viscous Liquid Media, Jinjin Zhang, Fabien Josse, Stephen M. Heinrich, Nicholas J. Nigro, Isabelle Dufour, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

The resonant characteristics of laterally vibrating rectangular hammerhead microcantilevers in viscous liquid media are investigated. The rectangular hammerhead microcantilever is modeled as an Euler-Bernoulli beam (stem) and a rigid body (head). A modified semi-analytical expression for the hydrodynamic function in terms of the Reynolds number, Re, and aspect ratio, h/b, is proposed to rapidly evaluate the sensing characteristics. Using this expression, the resonance frequency, quality factor and normalized surface mass sensitivity are investigated as a function of the dimensions of the microcantilever and liquid properties. Guidelines for design of hammerhead microcantilever geometry are proposed to achieve efficient sensing platforms for …

Bs News July/August

Building Services Engineering

No abstract provided.

Nanowell-Trapped Charged Ligand-Bearing Nanoparticle Surfaces – A Novel Method Of Enhancing Flow-Resistant Cell Adhesion, Phat L. Tran, Jessica R. Gamboa, Katherine E. Mccracken, Mark R. Riley, Marvin J. Slepian, Jeong-Yeal Yoon

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Assuring cell adhesion to an underlying biomaterial surface is vital in implant device design and tissue engineering, particularly under circumstances where cells are subjected to potential detachment from overriding fl uid fl ow. Cell–substrate adhesion is a highly regulated process involving the interplay of mechanical properties, surface topographic features, electrostatic charge, and biochemical mechanisms. At the nanoscale level, the physical properties of the underlying substrate are of particular importance in cell adhesion. Conventionally, natural, pro-adhesive, and often thrombogenic, protein biomaterials are frequently utilized to facilitate adhesion. In the present study, nanofabrication techniques are utilized to enhance the biological functionality of …

Impact Of Measurement Scale On Infiltration And Phosphorus Leaching In Ozark Floodplains, Derek M. Heeren, Garey A. Fox, Daniel E. Storm, Brian E. Haggard, Chad J. Penn, Todd Halihan

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Increased nutrient loads have resulted in several adverse impacts on surface water quality, including excessive algal growth, fish kills, and drinking water taste and odor issues across the United States and especially in the Ozark ecoregion of northeastern Oklahoma and northwestern Arkansas. The significance of this problem has been highlighted by litigation, with one case even reaching the U.S. Supreme Court (Arkansas et al. v. Oklahoma et al., 503 U.S. 91) which required the upstream state to meet downstream water quality standards. The overarching objective of this line of research was to characterize phosphorus leaching to alluvial aquifers in the …

Finite Element Modeling Of Phosphorus Leaching Through Floodplain Soils Dominated By Preferential Flow Pathways, Ryan P. Freiberger, Derek M. Heeren, Garey A. Fox

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Phosphorus is a critical nutrient in soils, providing both positive and negative effects to different systems. While optimum crop growth requires a range of P above 0.2 mg/L, preventing surface water enrichment generally requires P to be below 0.03 mg/L. Proper application and control of phosphorus is important to increase farming efficiency and to protect freshwater systems from toxic algal growth. While the movement of phosphorus through many soil types has been well-documented, the presence of highly conductive, gravel outcrops and macropores in soil can have a significant, poorly-documented effect on phosphorus movement. In the Ozark ecoregion, for example, the …

Application Of Isothermal Calorimetry To The Study Of Phosphorus Sorption Onto Soils In A Flow-Through System, Chad J. Penn, Derek M. Heeren, Garey A. Fox

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The degree, mechanisms, and kinetics of phosphorus (P) sorption onto soils can have a significant influence on leaching losses of P from soil. The objectives of this study were to measure the impact of retention time (RT) on P sorption in a flow-through system intended to simulate downward movement of a P solution through two different riparian soils, and determine if isothermal titration calorimetry (ITC) can provide useful information reflective of flow-through results. Topsoil from two riparian/alluvial soils was sampled and characterized for P concentrations and parameters related to P sorption. Flow-through P sorption experiments were conducted in order to …

A Study Of Bicycle Signal Compliance Employing Video Footage, Sam R. Thompson, Kirk Paulsen, Christopher M. Monsere, Miguel A. Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

An overview of bicycle signal compliance.

Evaluation Of The Performance Of The Sydney Coordinated Adaptive Traffic System (Scats) On Powell Boulevard In Portland, Or, Miguel A. Figliozzi, Christopher Monsere

Civil and Environmental Engineering Faculty Publications and Presentations

The Sydney Coordinated Adaptive Traffic System (SCATS) is used to mitigate traffic congestion along urban arterial corridors. Although there has been research on SCATS' performance, this report combines three different areas of research about SCATS that are not known to be represented in any research literature. These include: (a) the relationship between SCATS, traffic volumes, and Transit Signal Priority (TSP); (b) between TSP and traffic conditions; and (c) the correlation between signal timing and air quality; in particular, human exposure to the air pollutant PM2.5 at intersections. In addition, this research looked at the key factors affecting transit user exposure …

Developing A Model To Enhance Labor Productivity Using Bridge Construction Benchmark Data, Seonghoon Kim, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

The Labor Working Status Monitoring (LWSM) Model that incorporates the WRITE and the industry benchmark data was developed through the five steps to enhance labor productivity in bridge construction operations. The first step of the development process was to conduct a literature review, followed by the second step which was to develop the WRITE. During the development, the authors identified the necessary hardware and software for the WRITE and outlined a schematic to show the connection of major hardware components. The third step was to develop the LWSM Model for monitoring the on-site construction labor working status by comparing data …

The Effect Of Microencapsulated Phase-Change Material On The Compressive Strength Of Structural Concrete, Chad Norvell, David J. Sailor, Peter Dusicka

Mechanical and Materials Engineering Faculty Publications and Presentations

Latent heat energy storage through phase-change materials (PCMs) is one possible strategy to control interior temperatures in buildings, improve thermal comfort, and passively reduce building energy use associated with heating and cooling. While PCMs integrated into building structure elements have been studied since the 1970s, challenges of integrating PCMs into building materials while maintaining their heat storage benefits have limited their application in practice. The recent introduction of microencapsulated phase-change materials provides the energy storage capability of PCMs in micron-scale, chemically-inert capsules that can be easily integrated into composite materials such as gypsum wallboard and concrete. The size and physical …

Driver Fatigue Enforcement Techniques And Their Effect On Crashes, Carrie Mohlman

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

Fatigued driving is a type of driver impairment caused by a lack of sleep, sleep disorders, long drive times, etc. Fatigued driving enforcement aims to improve safety by removing impaired drivers from the roadway. While fatigued driving is detrimental to safety, there exists the issue of identifying fatigue. There is a range between being awake and asleep and, in order to improve safety, enforcement officers must be able to identify the point at which drivers are impaired.

This thesis investigates potentially effective fatigued driving enforcement techniques for use by enforcement officers. These techniques were investigated through three primary means: a …

Assessing The Impact Of Speed Limit Reduction Near Signalized High Speed Intersections Equipped With Advance Warning Flashers: A Case Study In Nebraska, Shefang Wang

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

This thesis evaluated the effects of 5 mph and 10 mph speed limit reductions in the vicinity of high-speed, signalized intersections equipped with Advance Warning Flashers (AWF). The selected methodology involved a field study of the impact of speed limit reduction at 7 high-speed, signalized intersections with AWF, using quantile regression models developed for speed. The quantile regression models for speed indicated that reduction of the speed limit from 60 mph to 55 mph did not have significant impact on observed speed during the green time. However, it was found that speed limit reduction from 65 mph to 55 mph …

Structural Reliability Analysis Of Corroded Steel Girder Bridge, Mohammed Shaalan Al Badran

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

The natural aging, environmental impact, and appropriate design are certainly playing a serious role in safety of the bridges function. The functional safety of bridge constitutes a prime element of the transportation system serving commuters, passengers and freight. According to Federal Highway Administration, the steel bridges share represents a large amount of the United States’ bridges. In last century, the collapse of both the Silver Bridge at Point Pleasant, West Virginia over the Ohio River on December 15, 1967 and over the Mianus River Bridge in Connecticut on June 28, 1983 showed that steel corrosion has been the leading reason …

Velocity Measurements Of The Flow Over A Gate-Controlled Weir Structure, Mohamed M. Jalloh

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

The South Florida Water Management District (SFWMD) uses G304 control structures to manage flow into and out of a large storm-water treatment area (STA). These structures consist of a lateral unsuppressed weir, a sluice gate and a corrugated culvert for flow control and transfer through an embankment. For better flow control in the STAs, it is imperative to accurately measure the discharge through the G304 control structures and to determine the approach velocity over the weir for different field scenarios.

Flow behavior of the G304 structure was examined in a prototype during two days of testing for two canal headwater …

Cable Median Barrier Failure Analysis And Remediation Phase Ii, Cody S. Stolle, Dean L. Sicking, Ronald K. Faller, John D. Reid

Nebraska Department of Transportation: Research Reports

Cable median barrier crashes from a total of 12 states were analyzed. Crash data included scene diagrams, photographs, and field measurements, crash narratives, although the availability of data in each crash varied.

Major contributors to penetration crash propensity were identified: diving underride, in which the front end of the vehicle dropped below the bottom cable; prying, in which the vehicle profile caused cable separation or lifting; override; bouncing override, in which the vehicle rebounded after contact with the back slope and bounced over the top of the barrier; system failure, in which one component failure or design failure prevented the …

Isolation And Characterisation Of Micro-Organisms With Industrial Importance From Sisal Bole Rots, Consolatha Mhaiki

Tanzania Journal of Engineering and Technology (TJET)

Investigation of microorganisms naturally acclimatized to Agave hybrid H 11648 (sisal bole rot) was conducted, with the aim of isolating and characterizing Aspergillus niger strains for industrial use. Microorganism were identified morphologically and then confirmation made by polymerase chain reaction (PCR). Results showed the existence of four major groups, listed in order of abundances as follows; Aspergilli (36.0±0.8) %, Penicillin (28.0±0.1) %, Yeast (15.0±1.6) %and Fusarium (10.0±0.12) %. The main groups of Aspergilli strains were A. nidulans, A. tamari and A. niger in ratios (3:2:2), respectively. Several endo-spore forming non-enteric gram (-) rods and coccid bacteria identified by API 20 …

Improvement Of Hydraulic Press For Vegetable Oil Expression In Rural Areas, I. P. Bateebe

Tanzania Journal of Engineering and Technology (TJET)

Cultivation of oil producing crops especially Jatropha and croton as source of vegetable oil for biodiesel production is being encouraged in rural areas. To recover oil from seed, manual press is the feasible method in rural areas where there is no electricity. Research was conducted to improve hydraulic oil press machine for rural application. Factors affecting oil recovery were found to be: moisture content of seeds, operating pressure, seed oil content, and the amount of seeds pressed per batch. Percentage oil recovery was improved by reducing diameter of press cylinder, hence increasing expression pressure, and either reducing amount of seed …