Engineering Commons^™

Long-Term Functionality Of Rural Water Services In Developing Countries: A System Dynamics Approach To Understanding The Dynamic Interaction Of Causal Factors, Jeffrey P. Walters, Amy N. Javernick-Will

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Research has shown that sustainability of rural water infrastructure in developing countries is largely affected by the dynamic and systemic interactions of technical, social, financial, institutional, and environmental factors that can lead to premature water system failure. This research employs systems dynamic modeling, which uses feedback mechanisms to understand how these factors interact dynamically to influence long-term rural water system functionality. To do this, the research first identified and aggregated key factors from literature, then asked water sector experts to indicate the polarity and strength between factors through Delphi and cross impact survey questionnaires, and finally used system dynamics modeling …

Integrating Ecological And Engineering Concepts Of Resilience In Microbial Communities, Hyun-Seob Song, Ryan S. Renslow, Jim K. Fredrickson, Stephen R. Lindemann

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Many definitions of resilience have been proffered for natural and engineered ecosystems, but a conceptual consensus on resilience in microbial communities is still lacking. We argue that the disconnect largely results from the wide variance in microbial community complexity, which range from compositionally simple synthetic consortia to complex natural communities, and divergence between the typical practical outcomes emphasized by ecologists and engineers. Viewing microbial communities as elasto-plastic systems that undergo both recoverable and unrecoverable transitions, we argue that this gap between the engineering and ecological definitions of resilience stems from their respective emphases on elastic and plastic deformation, respectively. We …

A New Methodology For Evaluating The Effectiveness Of Bus Rapid Transit Strategies, Ahmad Alomari

Electronic Theses and Dissertations

Over the last few years, public transportation has become more desirable as capacity of existing roadways failed to keep up with rapidly increasing traffic demand. Buses are one of the most common modes of public transportation with low impact on network capacity, especially in small and congested urban areas. However, the use of regularly scheduled buses as the main public transport mode can become useless with the presence of traffic congestion and dense construction areas. In cases like these, innovative solutions, such as bus rapid transit (BRT), can provide an increased level of service without having to resort to other, …

Drinking Water Infrastructure Assessment With Teleconnection Signals, Satellite Data Fusion And Mining, Sanaz Imen

Electronic Theses and Dissertations

Adjustment of the drinking water treatment process as a simultaneous response to climate variations and water quality impact has been a grand challenge in water resource management in recent years. This desired and preferred capability depends on timely and quantitative knowledge to monitor the quality and availability of water. This issue is of great importance for the largest reservoir in the United States, Lake Mead, which is located in the proximity of a big metropolitan region - Las Vegas, Nevada. The water quality in Lake Mead is impaired by forest fires, soil erosion, and land use changes in nearby watersheds …

Bs News January/February

Building Services Engineering

No abstract provided.

The Applicability Of Western Management In The Middle East, Zamaan Al-Shabbani

Theses and Dissertations--Civil Engineering

The Middle Eastern construction industry is still suffering from cost overruns, delays, and disputes. Inefficient management practices and lack of management are frequently reported reasons for such problems. Researchers attribute such problems to the traditional management practices that are utilized in the Middle East. However, International companies who practice their best management strategies are still suffering from the same problems. These issues become more significant in joint ventures when two different management styles work together. Therefore, it becomes crucial to understand the characteristics of Middle Eastern construction environment in terms of the management practices and regulations that are used and …

Quality Control For Wet-Mix Fiber Reinforced Shotcrete In Ground Support, Lihe (John) Zhang, Dudley R. Morgan

Shotcrete for Underground Support XII

No abstract provided.

Band To Band Calibration And Relative Gain Analysis Of Satellite Sensors Using Deep Convective Clouds, Suman Bhatta

Electronic Theses and Dissertations

Two calibration techniques were developed in this research. First, a calibration technique, in which calibration was transferred to cirrus band and coastal aerosol band from well calibrated reflective bands of Landsat 8 using SCIAMACHY Deep Convective Cloud (DCC) spectra. Second, a novel method to derive relative gains using DCCs and improve the image quality of cirrus band scenes was developed. DCCs are very cold, bright clouds located in the tropopause layer. At small sun elevation and sensor viewing angles, they act as near Lambertian solar reflectors. They have very high signal to noise ratio and can easily be detected using …

An Adaptive Photovoltaic Topology To Overcome Shading Effect In Pv Systems, Mohamed Amer Chaaban, Lana El Chaar, Mahmoud Alahmad

Durham School of Architectural Engineering and Construction: Faculty Publications

Shading in photovoltaic systems can cause many undesired effects.When shading occurs, the power generated from the PV system is much less than nominal power, increasing the electrical mismatching losses between PV system components. Active research to address this power loss focuses on static and adaptive systems.This paper addresses an adaptive system solution and proposes a new method to adaptively overcome losses due to shading during low radiation conditions. In addition, a statistical analysis for choosing the most feasible and efficient configuration for the system size is presented. The proposed system has been validated under shade conditions in a simulation and …

Quantification Of Food Waste Disposal In The United States: A Meta-Analysis, Krista L. Thyberg, David J. Tonjes, Jessica Gurevitch

Technology & Society Faculty Publications

Food waste has major consequences for social, nutritional, economic, and environmental issues, and yet the amount of food waste disposed in the U.S. has not been accurately quantified. We introduce the transparent and repeatable methods of meta-analysis and systematic reviewing to determine how much food is discarded in the U.S., and to determine if specific factors drive increased disposal. The aggregate proportion of food waste in U.S. municipal solid waste from 1995 to 2013 was found to be 0.147 (95% CI 0.137-0.157) of total waste, which is lower than that estimated by USEPA for the same period (0.176). The proportion …

Sustainable Disposal Of Coal Processing Waste Streams, Mohammad Rezaee

Theses and Dissertations--Mining Engineering

Modern coal preparation facilities incorporate a wide array of solid-solid and solid-liquid separation processes for rejecting mineral matter to meet market specifications. The coarse mineral matter is typically placed into engineered refuse piles whereas the fine refuse is either stored in impoundments or co-disposed with the coarse refuse. The discharge water from the refuse material represents an environmental concern due to the potential release of trace elements, and the subsequent elevation of total dissolved solids and conductivity. The research findings reported in this dissertation addresses sustainable coal processing waste disposal through using strategies aimed at minimizing the environmental impacts. To …

Introducing Pbl Into Civil And Structural Engineering, Niall Holmes, Una Beagon

Teaching Fellowships

The benefits of problem based learning for students are a deeper understanding of lecture material, and the development of problem solving and collaboration skills which will greatly enhance their educational experience. This approach has been successful in other programmes as it departs from the traditional ‘what I am told I need to know’ to ‘what I need to know to solve the problem’ promoting self-directed learning. Lecturers in turn transition from the giver of information to the facilitator of learning through support, guidance and monitoring. This project introduced an active learning element into two concrete technology modules by replacing traditional …

A Technical And Cultural Feasibility Assessment Of Household Microbial Fuel Cells For Use In Hanan'g District, Tanzania, Erinn Kunik

Dissertations, Master's Theses and Master's Reports

Microbial fuel cells (MFCs) are an emerging electricity generation technology that has the potential for use in developing countries. This study assessed the feasibility of using MFCs in Tanzania through technical analysis of a MFC prototype alongside with interviews with Tanzanians for a cultural feasibility assessment of MFCs. For the technical analysis, this study evaluated the inputs needed for a household MFC to operate and produce electricity with cattle manure as a fuel and evaluated the electrochemical and chemical performance as well as the fecal coliform reduction of the manure during MFC operation. For this study, a MFC was built …

Calculation Of Surface Leakage Currents On High Voltage Insulators By Ant Colony Algorithm-Supported Fem, Dursun Öztürk, Mehmet Cebeci̇

Turkish Journal of Electrical Engineering and Computer Sciences

The weakness of the outer insulation at high voltages is the reduction of the surface resistance as a result of the environmental pollution yielding formation of flashover due to the surface leakage currents. In this study, it was shown how to calculate the surface leakage currents resulting in flashover in polluted insulators and therefore power cuts by means of the ant colony algorithm (ACA). For this purpose, first, field distribution on the sample insulator surface in question was defined by the Laplace equation ($\nabla^{2}$V = 0). With the help of the finite element method (FEM), the Laplace equation was obtained …

The Integrated Control Of Fuzzy Logic And Model-Based Approach For Variable-Speed Wind Turbine, Jian Yang, Dongran Song, Hua Han, Pengsha Tong, Ling Zhou

Turkish Journal of Electrical Engineering and Computer Sciences

For a variable-speed wind turbine (VSWT), the primary objective of control is to maximize power generation while maintaining the desired rotor speed and avoiding equipment overloads. To fulfill the control objectives, the classical model-based control (MBC) has been widely used, which refers to two controllers: torque controller (TC) and pitch controller (PC). In this work, the drawbacks of MBC for VSWTs are studied extensively. It reveals that there are transition issues between the TC and PC, and over-speed problems under large turbulent wind when only MBC is taken. To improve the control performance of the VSWT, an integrated control solution …

Transient Stability Analysis Of Vsc Hvdc Transmission With Power Injection On The Dc-Link, Agha Francis Nnachi, Josiah Munda, Dan Valentine Nicolae, Augustin Mabwe Mpanda

Turkish Journal of Electrical Engineering and Computer Sciences

The utilization of a DC-link transmission corridor of embedded VSC HVDC for a DC power injection from renewable energy sources to increase the power flow capability and AC network stability support is a promising technology. However, DC faults on the DC transmission line are likely to threaten the system's operation and stability, especially when the DC power injection exceeds certain limits. A DC single line-to-earth fault is the most likely fault scenario and its effect on the VSC HVDC operation will depend on the earth-loop impedance. Adding an injection point on the DC-link will reduce the earth-loop impedance, hence imposing …

Renewable Energy Integration In Smart Grids-Multicriteria Assessment Using The Fuzzy Analytical Hierarchy Process, Aleksandar Janjic, Suzana Savic, Lazar Velimirovic, Vesna Nikolic

Turkish Journal of Electrical Engineering and Computer Sciences

Unlike the traditional way of efficiency assessment of renewable energy sources integration, the smart grid concept is introducing new goals and objectives regarding increased use of renewable electricity sources, grid security, energy conservation, energy efficiency, and deregulated energy market. Possible benefits brought by renewable sources integration are evaluated by the degree of the approach to the ideal smart grid. In this paper, fuzzy analytical hierarchy process methodology for the integration efficiency has been proposed, taking into account the presence of multiple criteria of both qualitative and quantitative nature, different performance indicators, and the uncertain environment of the smart grid. The …

A Novel Approach For Identifying Cloud Clusters Developing Into Tropical Cyclones, Chaunte' W. Lacewell

Dissertations

Providing advance notice of rare events, such as a cloud cluster (CC) developing into a tropical cyclone (TC), is of great importance. Having advance warning of such rare events possibly can help avoid or reduce the risk of damages and allow emergency responders and the affected community enough time to respond appropriately. Considering this, forecasters need better data mining and data driven techniques to identify developing CCs. Prior studies have attempted to predict the formation of TCs using numerical weather prediction models as well as satellite and radar data. However, refined observational data and forecasting techniques are not always available …

Influence Of Spatial Variations Of Railroad Track Stiffness And Material Inclusions On Fatigue Life, Celestin Nkundineza

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Railroad transportation is very important for economic growth and effective maintenance is one critical factor for its economic sustainability. The high repetitive forces from a moving railcar induce cyclic stresses that lead to rail bending and potential deterioration due to fatigue crack initiation and propagation. Previous research for prediction of fatigue life has been done under the assumptions of a uniform track bed and a homogeneous rail. However the spatial variation of the track stiffness is expected to increase the maximum stresses in the rail and, therefore, accelerate the fatigue process. The research described in this dissertation is focused on …

Predicting Scenarios For Successful Autodissemination Of Pyriproxyfen By Malaria Vectors From Their Resting Sites To Aquatic Habitats; Description And Simulation Analysis Of A Field-Parameterizable Model, Samson Sifael Kiware, George F. Corliss, Stephen Merrill, Dickson W. Lwetoijera, Gregor J. Devine, Silas Majambere, Gerry F. Killeen

Electrical and Computer Engineering Faculty Research and Publications

Background

Large-cage experiments indicate pyriproxifen (PPF) can be transferred from resting sites to aquatic habitats by Anopheles arabiensis - malaria vector mosquitoes to inhibit emergence of their own offspring. PPF coverage is amplified twice: (1) partial coverage of resting sites with PPF contamination results in far higher contamination coverage of adult mosquitoes because they are mobile and use numerous resting sites per gonotrophic cycle, and (2) even greater contamination coverage of aquatic habitats results from accumulation of PPF from multiple oviposition events.

Methods and Findings

Deterministic mathematical models are described that use only field-measurable input parameters and capture the biological …

Transport Properties Of Wet-Mix Shotcrete, Lihe (John) Zhang, Dudley R. Morgan

Shotcrete for Underground Support XII

No abstract provided.

Icao Aviation System Block Upgrades: A Method For Identifying Training Needs, Rebecca K. Lutte

Aviation Institute Faculty Publications

Since the mid-1970s, air traffic growth has expanded two-fold once every fifteen years (ICAO, 2013). The ICAO Global Air Navigation Plan (GANP) is a roadmap to achieve a “vision of an integrated, harmonized, and globally interoperable air traffic management (ATM) system” (ICAO, 2012, p. 1). A component of the GANP is the Aviation System Block Upgrades (ASBU), a framework for achieving that vision. A collaborative approach led by ICAO between public and private organizations and member states resulted in the development of the ASBU framework. However, obstacles exist for successful implementation. One area of concern is the need for training …

Korean Anthracite Coal Cleaning By Means Of Dry And Wet Based Separation Technologies, Majid Mahmoodabadi

Theses and Dissertations--Mining Engineering

Korean coals are typically high rank anthracite characterized by high ash content and difficult cleaning characteristics. The main objective of the study was to evaluate the feasibility of treating various size fractions within the coal using an assortment of physical coal cleaning technologies. Dry cleaning is preferred due to the friability of the coal. As such, three pneumatic processes were tested including Ore Sorting for the plus 10 mm material, Air Table Separation for 10 x 1 mm fraction and Tribo-electric Separator for - 1 mm fraction. The Dense Medium Cyclone is known to be one of the most efficient …

Pilot Scale Demonstration And Evaluation Of Innovative Non-Deslimed Non-Classified Gravity-Fed Hm Cyclone, Yumo Zhang

Theses and Dissertations--Mining Engineering

Coal preparation plants are required in some cases to produce a high-grade product using a low specific gravity cut-point. For these situations, a second higher gravity separation would be desirable to generate a mid-grade product that can be utilized for electricity generation thereby maximizing coal recovery. A study was conducted to evaluate the potential of achieving efficient separations at two different density cut-points in a single stage using a three-product dense medium cyclone. Variations in density cut-point and process efficiency values were quantified as a function of the feed medium density, feed medium-to-coal ratio, and feed pressure using a three-level …

Analysis Of The Armps Database Using Flac3d; A Pillar Stability Comparison For Room And Pillar Coal Mines During Development, Ali Soltani

Theses and Dissertations--Mining Engineering

Designing a safe and economical mining activity is the main goal of every mine design engineer. With the rise of computer modeling in mine design there is a need for a standardized method to use geologic characterization of rocks in engineering design. In this research, first a review of empirical methods will be conducted and after that a step-by-step method is presented to adequately use FLAC3D, for development pillars, in room and pillar mine in development stage. ARMPS database is used to evaluate the FLAC3D model results. ARMPS database consists of 645 case study in room and pillar mines. 170 …

Modeling Social Norms In Real-World Agent-Based Simulations, Rahmatollah Beheshti

Electronic Theses and Dissertations

Studying and simulating social systems including human groups and societies can be a complex problem. In order to build a model that simulates humans' actions, it is necessary to consider the major factors that affect human behavior. Norms are one of these factors: social norms are the customary rules that govern behavior in groups and societies. Norms are everywhere around us, from the way people handshake or bow to the clothes they wear. They play a large role in determining our behaviors. Studies on norms are much older than the age of computer science, since normative studies have been a …

Characterization Of Two Biochars Derived From Horse Muck And Their Ability To Reduce Pathogen Transport In Soil, David Griffith

Theses and Dissertations--Biosystems and Agricultural Engineering

Biochars have been created and characterized from a variety livestock manure biomass including poultry, dairy, and swine. However, no research has been conducted on the physical and chemical makeup of biochar pyrolyzed from horse muck. Two horse muck derived biochars containing either straw (HS) or woodchip (HW) bedding were pyrolyzed at 700°C and characterized for their physical and chemical properties. Tests revealed both biochars had high alkalinity, moderate specific conductivity, and low surface area as compared to other biochars in the literature. HS contained more mineral structures than HW. Scanning electron microscopy presented differences in particle shape, size, and presence …

Exploration Of Cannabinoid And Opioid Agents From Plants Used In Traditional Medicine, John Fitzpatrick

Honors Theses

Ten plants, with known medicinal uses, were gathered to study for their possible production of secondary metabolites that act as opioid and cannabinoid agents. All plants were subjected to in vitro bioassays testing for their affinity for the opioid and cannabinoid receptors. Banisteriopsis caapi extracts displayed the greatest affinity for both opioid and cannabinoid receptors. B. caapi extracts underwent column fractionation yielding fractions that were subjected to further in vitro studies. We discovered that the ethanolic extract of this plant (foliage) binds to all three opioid receptors (µ, κ and δ) and cannabinoid receptors (CB1 and CB2) with values ranging …

A Microsimulation Of Novel Intersection Designs, Aman Kinfemichael Woldetinsae

Civil and Environmental Engineering Master's Project Reports

The focus of this project is to see how a turbo roundabout and a protected intersection designs behave when they are applied on two study sites in Portland, OR. PTV VISSM is used to model, analyze and compare the performances of these designs with the existing intersection. In addition, the best features of the protected intersection and the turbo roundabout were combined to create a new intersection design that is safer for the bicyclists and also performs better than the existing intersection.

The analysis is conducted for five different volume scenarios for both the study sites. The results of the …

The Skill Of Seasonal Ensemble Low-Flow Forecasts In The Moselle River For Three Different Hydrological Models, Mehmet C. Demirel, Martijn Booij, Arjen Hoekstra

Civil and Environmental Engineering Faculty Publications and Presentations

This paper investigates the skill of 90-day low-flow forecasts using two conceptual hydrological models and one data-driven model based on Artificial Neural Networks (ANNs) for the Moselle River. The three models, i.e. HBV, GR4J and ANN-Ensemble (ANN-E), all use forecasted meteorological inputs (precipitation P and potential evapotranspiration PET), whereby we employ ensemble seasonal meteorological forecasts. We compared low-flow forecasts for five different cases of seasonal meteorological forcing: (1) ensemble P and PET forecasts; (2) ensemble P forecasts and observed climate mean PET; (3) observed climate mean P and ensemble PET forecasts; (4) observed climate mean P and PET and (5) …