Civil and Environmental Engineering Commons^™

Thermographic Laplacian-Pyramid Filtering To Enhance Delamination Detection In Concrete Structure, Chongsheng Cheng, Ri Na, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Despite decades of efforts using thermography to detect delamination in concrete decks, challenges still exist in removing environmental noise from thermal images. The performance of conventional temperature-contrast approaches can be significantly limited by environment-induced non-uniform temperature distribution across imaging spaces. Time-series based methodologies were found robust to spatial temperature non-uniformity but requires extended period to collect data. A new empirical image filtering method is introduced in this paper to enhance the delamination detection using blob detection method that originated from computer vison. The proposed method employs a Laplacian of Gaussian filter to achieve multi-scale detection of abnormal thermal patterns by …

Evaluation Of Selected Watershed Characteristics To Identify Best Management Practices To Reduce Nebraskan Nitrate Loads From Nebraska To The Mississippi/Atchafalaya River Basin, Aaron R. Mittelstet, Troy E. Gilmore, Tiffany Messer, Daran Rudnick, Thomas Heatherly

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Nebraskan streams contribute excess nitrogen to the Mississippi/Atchafalaya River Basin and Gulf of Mexico, which results in major water-quality impairments. Reducing the amount of nitrogen (N) exported in these streams requires the use of best management practices (BMPs) within the landscape. However, proper BMP utilization has rarely been statistically connected to potential controls of N export within watersheds, particularly precipitation and soil characteristics. In this study, 19 watershed variables were evaluated in five categories (hydrological, physiographic, point sources, land use, and soil properties) to determine the characteristics that influenced variable nitrate nitrogen (NO₃-N) concentrations in 17 Nebraska watersheds …

Changes In Snow Phenology From 1979 To 2016 Over The Tianshan Mountains, Central Asia, Tao Yang, Qian Li, Sajjad Ahmad, Hongfei Zhou, Lanhai Li

Civil and Environmental Engineering and Construction Faculty Research

Snowmelt from the Tianshan Mountains (TS) is a major contributor to the water resources of the Central Asian region. Thus, changes in snow phenology over the TS have significant implications for regional water supplies and ecosystem services. However, the characteristics of changes in snow phenology and their influences on the climate are poorly understood throughout the entire TS due to the lack of in situ observations, limitations of optical remote sensing due to clouds, and decentralized political landscapes. Using passive microwave remote sensing snow data from 1979 to 2016 across the TS, this study investigates the spatiotemporal variations of snow …

Inactivation Of The Bacterial Pathogens Staphylococcus Pseudintermedius And Acinetobacter Baumannii By Butanoic Acid, G. M. Kennedy, M. Y. Min, J. F. Fitzgerald, M. T. Nguyen, S. L. Schultz, M. T. Crum, Jeffrey A. Starke, M. A. Butkus, D. D. Bowman, M. P. Labare

Civil and Environmental Engineering Faculty Research and Publications

Aims

This study was performed to evaluate the efficacy of butanoic acid against bacterial pathogens including Acinetobacter baumannii and Staphylococcus pseudintermedius.

Methods and Results

Vegetative bacteria were exposed to butanoic acid in vitro and log reduction was quantified using viable count assays. The maximum (8 and 9) log inactivation was determined by qualitatively assaying for growth/no-growth after a 48-h incubation (37°C). Membrane integrity after exposure to butanoic acid was determined by propidium iodide staining, scanning electron microscopy, membrane depolarization and inductively coupled plasma analysis. Cytosolic pH was measured by 5-(6-)carboxyfluorescein succinimidyl ester.

Conclusions

Inhibitory concentrations of butanoic acid ranged …

Study Of Various Construction Job Functions To Address Workforce Challenge, Abraham Bonilla, Dhaval Gajjar, Kenneth Sullivan

The Professional Constructor

Lack of construction workforce is one of the most predominant challenges faced by the construction industry. It is predicted that the industry will have a major shortage of skilled labor in the next decade due to the retirement of baby boomers and the lack of new talent entering the industry to replace these baby boomers. To attract young talent into the construction industry, it is critical to make them aware about the industry regarding various job functions as it relates to job satisfaction, compensation and career fulfilment. The purpose of this study is to gain insight of various construction job …

Consumer Perception And Willingness To Pay For Extended New Home Warranties, C. Todd Usher, Joseph M. Burgett

The Professional Constructor

Construction standards and methods for building new homes has improved over the last two decades resulting in significant improvements in energy efficiency, comfort, indoor air quality, and durability of new homes. Despite these improvements, the most common builder warranty for a new home in the United States ranges from 6 months to two years in duration. During the past two decades, manufacturer warranties on other durable goods such as automobiles has increased significantly. This study measures consumer perceptions of extended 12 year new home warranties with a survey completed by 162 adults in the United States. The results indicate that …

Wastewater Treatment And Nitrogen Removal In Bench-Scale Photobioreactors Operated With Solids Recycling, Erik Hoffnagle

Master's Theses

This thesis examines the effect of solids recycling on nitrification, organic carbon removal, and algal-bacterial productivity in bench-scale photobioreactors (PBRs) simulating winter pond conditions in San Luis Obispo, California and a 6-acre raceway system in Delhi, California. Two sets of duplicate photobioreactors operated with or without solids recycling were fed primary clarifier effluent (1^oEff) for the first experiment, and facultative pond effluent (FAC) for the second experiment.

In both experiments mean productivity was lower in solids recycled PBRs (3.67 and 2.3 g/m²-day), than in controls without solids recycling (4.15 and 3.9 g/m²-day). When fed …

Implementing Unbiased Decision-Making In Construction: A Lean Approach, Somik Ghosh, Michelle Robinette, Howard Tapia

The Professional Constructor

Construction project-teams are frequently faced with the task of decision-making as part of their responsibility. The positive effects of the decisions made at various stages of the projects lead to improved project performances, while negative effects can hinder the performances. The project teams take up the task of decision-making surrounded by multiple criteria, which can be arduous and clouded with subjectivity. This paper presents an approach based on the Lean principle of providing more autonomy to the project-teams and supporting collaborative and decentralized process in pursuit of unbiased decision-making. This Lean way of decision-making is formalized as Choosing by Advantage …

Attracting And Retaining Future Top Performing Employees: A Student Perspective, Julia Allen

The Professional Constructor

This essay provides insight as to how construction companies can both attract and retain top performing employees. By making the standard interview and recruiting processes more personal, construction companies can evaluate potential hires to see is they are a good fit for the company for years to come. Once employees are hired, companies then need to provide opportunities for both personal and professional growth. From personal experiences, I share the characteristics I find most important in an ideal employer and emphasize the importance of having an in-depth, genuine conversation with potential hires.

Attracting And Retaining Top Employees By Placing Proper Value On Their Contribution To The Company, Joseph Franklin Iii

The Professional Constructor

Due to an optimistic economic future, construction companies want to attract and retain the best employees to ensure company success. Because of a larger job market, employees now look for the optimal work values to be met in long-term employment opportunities. Construction companies have many challenges when attracting and retaining top employees in a growing market. Therefore; it is beneficial for employers to consider the evolving work values of employees and for these values to be promoted throughout company culture. Offering employees good value for their contribution to the company attracts and retains top employees.

Social Resources Of Mechanical Contracting Management Personnel, Blake Wentz, Sarabeth Gandara

The Professional Constructor

The construction industry in the United States is projected to grow faster than average compared to other industries through 2026. The Baby Boomer generation is leaving a significant gap in the labor force as they reach retirement. Retention of high quality management personnel is a priority for all companies in the construction industry, including mechanical contracting companies. Firms that fail to retain these employees will be left with an understaffed and underqualified workforce, which will hinder their ability to be competitive in the marketplace. In order to aid in retention efforts, mechanical contracting firms need to focus their attention on …

Essay Winners, American Institute Of Constructors

The Professional Constructor

No abstract provided.

Attracting And Retaining Future Top Performing Employees, Caleb Bardin

The Professional Constructor

The goal of this essay is to explore the key factors that influence top-performing employees’ decisions to change companies or remain with their current employers. A few of these factors are salary and benefits, work environment, and corporate advancement. This essay will address such factors and propose solutions using my own educational and professional experience. A key theme to note is the constant evaluation of employees and workplace environment by employers. No company can hope to be successful or have the best people if this skill is not enhanced and implemented well.

Impact Of Water Mixing And Ice Formation On The Warming Of Lake Superior: A Model-Guided Mechanism Study, Xinyu Ye, Eric J. Anderson, Philip Y. Chu, Chenfu Huang, Pengfei Xue

Michigan Tech Publications, Part 1

The Laurentian Great Lakes are one of the most prominent hotspots for the study of climate change induced lake warming. Warming trends in large, deep lakes, which are often inferred by the observations of lake surface temperature (LST) in most studies, are strongly linked to the total lake heat content. In this study, we use a 3D hydrodynamic model to examine the nonlinear processes of water mixing and ice formation that cause changes in lake heat content and further variation of LST. With a focus on mechanism study, a series of process-oriented experiments is carried out to understand the interactions …

Climate‐Induced Changes In The Risk Of Hydrological Failure Of Major Dams In California, Iman Mallakpour, Amir Aghakouchak, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Existing major reservoirs in California, with average age above 50 years, were built in the previous century with limited data records and flood hazard assessment. Changes in climate and land use are anticipated to alter statistical properties of inflow to these infrastructure systems and potentially increase their hydrological failure probability. Because of large socioeconomic repercussions of infrastructure incidents, revisiting dam failure risks associated with possible shifts in the streamflow regime is fundamental for societal resilience. Here we compute historical and projected flood return periods as a proxy for potential changes in the risk of hydrological failure of dams in a …

Effect Of Stoniness On The Hydraulic Properties Of A Soil From An Evaporation Experiment Using The Wind And Inverse Estimation Methods, Nerea Arias, Iñigo Virto, Alberto Enrique, Paloma Bescansa, Riley Walton, Ole O. Wendroth

Plant and Soil Sciences Faculty Publications

Stony soils are distributed all over the world. The study of their characteristics has gained importance lately due to their increasing use as agricultural soils. The effect that rock fragments exert on the soil hydraulic properties is difficult to measure in situ, and is usually derived from the fine earth properties. However, the corrections used so far do not seem accurate for all types of stony soils. Our objective was to assess the adequacy of estimating the hydraulic properties of a stony soil from the fine earth ones by correcting the latter by the volume occupied by rock fragments. To …

Health Benefits From Upgrading Public Buses For Cleaner Air: A Case Study Of Clark County, Nevada And The United States, John O. Olawepo, L.-W. Antony Chen

School of Public Health Faculty Research

Public transit buses, which move more than 5 billion passengers annually in the United States (U.S.), can contribute substantially to the environmental health burden through emitted air pollutants. As a leader in transforming to cleaner bus fleets, the Regional Transport Commission of Southern Nevada (RTC) has been transitioning from diesel to compressed natural gas (CNG) transit buses since 1999. By 2017, ~75% of RTC’s buses operating in Clark County, Nevada were CNG-powered. This study assesses the health benefits of the venture using the US Environmental Protection Agency’s (EPA) Co-Benefits Risk Assessment (COBRA) model, considering the emission and exposure changes from …

Webinar: Rethinking Streets For Bikes: An Evidence Based Guide Of Bike-Friendly Street Retrofits, Marc Schlossberg, Roger Lindgren

TREC Webinar Series

There is a growing demand for better infrastructure and fewer barriers to biking and other forms of space-efficient micromobility. Tackling daily trips by bike is easier on the environment, healthier for users and non-users alike, uses precious urbanized public and private land more efficiently, costs taxpayers less to build and maintain infrastructure, and when routes are safe and comfortable, moving by bike is also fun! Complete Streets policies are being adopted across the country, and there is an active conversation around the safety imperative of a Complete Streets approach. Yet, local officials often need both design guidance and the …

Assessing Data Availability And Research Reproducibility In Hydrology And Water Resources, James H. Stagge, David E. Rosenberg, Adel M. Abdallah, Hadia Akbar, Nour A. Atallah, Ryan James

Civil and Environmental Engineering Faculty Publications

There is broad interest to improve the reproducibility of published research. We developed a survey tool to assess the availability of digital research artifacts published alongside peer-reviewed journal articles (e.g. data, models, code, directions for use) and reproducibility of article results. We used the tool to assess 360 of the 1,989 articles published by six hydrology and water resources journals in 2017. Like studies from other fields, we reproduced results for only a small fraction of articles (1.6% of tested articles) using their available artifacts. We estimated, with 95% confidence, that results might be reproduced for only 0.6% to 6.8% …

Limits To The World’S Green Water Resources For Food, Feed, Fiber, Timber, And Bioenergy, Joep F. Schyns, Arjen Y. Hoekstra, Martijn J. Booij, Rick J. Hogeboom, Mesfin Mekonnen

Daugherty Water for Food Global Institute: Faculty Publications

Green water––rainfall over land that eventually flows back to the atmosphere as evapotranspiration––is the main source of water to produce food, feed, fiber, timber, and bioenergy. To understand how freshwater scarcity constrains production of these goods, we need to consider limits to the green water footprint (WFg), the green water flow allocated to human society. However, research traditionally focuses on scarcity of blue water––groundwater and surface water. Here we expand the debate on water scarcity by considering green water scarcity (WSg). At 5 × 5 arc-minute spatial resolution, we quantify WFg and the maximum sustainable level to this footprint (WFg,m), …

Mechanical Behaviors Of Hydrogel-Impregnated Sand, Kejun Wen, Yang Li, Wei Huang, Catherine Armwood, Farshad Amini, Lin Li

Civil and Architectural Engineering Faculty Research

Hydrogel has been widely used in medical studies due to their unique integration of solid and liquid properties. There is limited studies of using hydrogel in construction materials. The goal of this study was to investigate the effect of hydrogel on mechanical behaviors of sandy materials. The effects of reaction time, sodium alginate content, and curing temperature on mechanical behaviors of hydrogel-impregnated sand were studied through unconfined compression tests, falling head permeability tests, consolidated and undrained triaxial tests, scanning electron microscopy, and durability tests. The unconfined compression strength (UCS) increased with sodium alginate content, but the hydraulic conductivity of hydrogel-impregnated …

Water Quality Modeling Of Mahabad Dam Watershed–Reservoir System Under Climate Change Conditions, Using Swat And System Dynamics, Mohammad Nazari-Sharabian, Masoud Taheriyoun, Sajjad Ahmad, Moses Karakouzian, Azadeh Ahmadi

Civil and Environmental Engineering and Construction Faculty Research

The total phosphorus (TP) concentration, as the primary limiting eutrophication factor in the Mahabad Dam reservoir in Iran, was studied, considering the combined impacts of climate change, as well as the scenarios on changes in upstream TP loadings and downstream dam water allocations. Downscaled daily projected climate data were obtained from the Beijing Normal University Earth System Model (BNU-ESM) under moderate (RCP4.5) and extreme (RCP8.5) scenarios. These data were used as inputs of a calibrated Soil and Water Assessment Tool (SWAT) model of the watershed in order to determine the effects of climate change on runoff yields in the watershed …

Flow-Induced Stresses And Displacements In Jointed Concrete Pipes Installed By Pipe Jacking Method, Moses Karakouzian, Mehrdad Karami, Mohammad Nazari-Sharabian, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

Transient flows result in unbalanced forces and high pressure in pipelines. Under these conditions, the combined effects of flow-induced forces along with sudden pipe displacements can create cracks in the pipeline, especially at the junctions. This situation consequently results in water leakage and reduced operational efficiency of the pipeline. In this study, displacements and stresses in a buried pressurized water transmission pipe installed by pipe jacking method are investigated using numerical modeling and considering interactions between fluid, pipe, and soil. The analyses were performed consecutively under no-flow, steady flow, and transient flow conditions, in order to investigate the effects of …

Quantifying And Correcting For Clay Content Effects On Soil Water Measurement By Reflectometers, Jasreman Singh, Tsz Him Lo, Daran Rudnick, Suat Irmak, Humberto Blanco-Canqui

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The presence of clay particles increases the specific surface area of a soil and can affect the calibration of electromagnetic soil water sensors including reflectometers. To quantify and correct for this effect in two relatively new reflectometers, three TDR315 and three CS655 sensors were installed in each of five soils with clay content ranging from 5 to 49%. As the soils were dried in a temperature controlled room, sensor reported soil volumetric water content (θ_v) according to the factory calibration was compared against reference θ_v determined by weighing the soils. Sensor reported θ_v was similar to …

The Influence Of Asphalt Ageing On Induction Healing Effect On Porous Asphalt Concrete, Shi Xu, Xueyan Liu, Amir Tabakovic, Erik Schlangen

Articles

Induction healing is a proven technology which is able to improve the self‐healing capacity of asphalt concrete. Healing is achieved via electromagnetic current produced by passing induction machine, where steel asphalt constituents heat up which in turn soften the bitumen in the asphalt layer, allowing it to flow and close cracks, repairing the damage. This paper reports on the study which investigated the influence of ageing on the healing capacity of Porous Asphalt (PA) concrete. Porous Asphalt concrete mix was prepared first, then subjected to an accelerated (laboratory) ageing process using a ventilated oven. In order to further evaluate the …

Modeling Of Grace-Derived Groundwater Information In The Colorado River Basin, Md Mafuzur Rahaman, Balbhadra Thakur, Ajay Kalra, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

Groundwater depletion has been one of the major challenges in recent years. Analysis of groundwater levels can be beneficial for groundwater management. The National Aeronautics and Space Administration’s twin satellite, Gravity Recovery and Climate Experiment (GRACE), serves in monitoring terrestrial water storage. Increasing freshwater demand amidst recent drought (2000–2014) posed a significant groundwater level decline within the Colorado River Basin (CRB). In the current study, a non-parametric technique was utilized to analyze historical groundwater variability. Additionally, a stochastic Autoregressive Integrated Moving Average (ARIMA) model was developed and tested to forecast the GRACE-derived groundwater anomalies within the CRB. The ARIMA model …

Aesthetics, Ethics, And Lose-Lose Dilemmas In The Anthropocen, Adam Liska

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Anthropogenic climate change will cause violence to increase globally, and nonlinear increases in sea level could cause a major escalation in global conflict. After 2100, a 22-meter sea-level rise is estimated here to dislocate two billion people from coastal areas. These impending civilization-changing events require us to again reevaluate our prevalent aesthetic preferences for luxury that produce a significant fraction of anthropogenic greenhouse gas emissions. Due to industrial inertia, a central dilemma discussed here is the contradictions between the goals and impacts of aesthetics and ethics. Either we lose our own well-being (a loss of high-emission aesthetics) for the benefit …

Identification Of Critical Source Areas (Csas) And Evaluation Of Best Management Practices (Bmps) In Controlling Eutrophication In The Dez River Basin, Hadi Babaei, Mohammad Nazari-Sharabian, Moses Karakouzian, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

Best Management Practices (BMPs) are commonly used to control pollution in the river basins. Prioritization of BMPs helps improve the efficiency and effectiveness of pollution reduction, especially in Critical Source Areas (CSAs) that produce the highest pollution loads. Recently, the Dez River in Khuzestan, Iran, has become highly eutrophic from the overuse of fertilizers and pesticides. In this basin, dry and irrigated farming produce 77.34% and 6.3% of the Total Nitrogen (TN) load, and 83.56% and 4.3% of the Total Phosphorus (TP) load, respectively. In addition, residential, pasture, and forest land uses together account for 16.36% of the TN and …

Addressing Challenges For Mapping Irrigated Fields In Subhumid Temperate Regions By Integrating Remote Sensing And Hydroclimatic Data, Tianfang Xu, Jillian M. Deines, Anthony D. Kendall, Bruno Basso, David W. Hyndman

Publications

High-resolution mapping of irrigated fields is needed to better estimate water and nutrient fluxes in the landscape, food production, and local to regional climate. However, this remains a challenge in humid to subhumid regions, where irrigation has been expanding into what was largely rainfed agriculture due to trends in climate, crop prices, technologies and practices. One such region is southwestern Michigan, USA, where groundwater is the main source of irrigation water for row crops (primarily corn and soybeans). Remote sensing of irrigated areas can be difficult in these regions as rainfed areas have similar characteristics. We present methods to address …

A Data Model To Manage Data For Water Resources Systems Modeling, Adel M. Abdallah, David E. Rosenberg

Civil and Environmental Engineering Faculty Publications

Current practices to identify, organize, analyze, and serve data to water resources systems models are typically model and dataset-specific. Data are stored in different formats, described with different vocabularies, and require manual, model-specific, and time-intensive manipulations to find, organize, compare, and then serve to models. This paper presents the Water Management Data Model (WaMDaM) implemented in a relational database. WaMDaM uses contextual metadata, controlled vocabularies, and supporting software tools to organize and store water management data from multiple sources and models and allow users to more easily interact with its database. Five use cases use thirteen datasets and models focused …