Engineering Commons^™

Enhancing Silymarin Fractionation Via Molecular Modeling Using The Conductor-Like Screening Model For Real Solvents, Emma C. Brace

Open Access Theses

The market for bio-based products from plant sources is on the rise. There is a global challenge to implement environmentally clean practices for the production of fuels and pharmaceuticals from sustainable resources. A significant hurdle for discovery of comparable plant-derived products is the extensive volume of trial-and-error experimentation required. To alleviate the experimental burden, a quantum mechanics based molecular modeling approach known as the COnductor-like Screening Model for Real Solvents (COSMO-RS) was used to predict the best biphasic solvent system to purify silymarins from an aqueous mixture. Silymarins are a class of flavonolignans present in milk thistle ( Silybum marianum …

Dynamic Green Split Optimization In Intersection Signal Design For Urban Street Network, Peng Jiao

Open Access Theses

In the past few decades, auto travel demand in the United States has significantly increased, but roadway capacity unfortunately has not expanded as quickly, which has led to severe levels of highway traffic congestion in many areas. In theory, the problem of congestion addressed through demand management and roadway expansion. However, system expansion in urban areas is difficult due to the extremely high cost of land; therefore, maximizing the existing capacity therefore often is considered the most realistic option. In urban areas, most of the traffic congestion and delays typically occur at signalized intersections. This thesis aims to prove the …

Investigating U.S. Resident Perceptions Of Corporate Social Responsibility In Food And Agriculture, Carissa Jae Morgan

Open Access Theses

Corporations are prioritizing corporate social responsibility (CSR) activities by investing in and actively promoting their social practices. In the U.S. of the modern food supply chain creates a unique challenge for corporations to address concerns about social issues of consumers and non-consumers alike. This study is motivated by the need to better understand individuals’ perceptions of CSR as it pertains to the food supply chain. In April 2015 an online survey collected information from 1,201 U.S. residents with the objective of investigating individuals’ perceptions of relative importance of eight prominent CSR areas relevant to food and agriculture. Demographic, household consumption, …

A Framework For Organizational Performance Assessment In The Construction Industry, Zenith Rathore

Open Access Theses

Organizations have been trying to increase their efficiency and improve their performance in order to achieve their goals. Organizational success is determined by various factors that impact organizational performance. Construction industry is a project based industry which is extremely dynamic in nature. The need to identify the weak points and search solutions to improve performance of construction organization is extremely crucial. Previous research works have primarily focused on the measurement of financial or tangible assets. Industry has always focused on measure of project success. However, previous studies lack the understanding of qualitative factors and their combine effect on organizational performance. …

A Methodology For Cooperation Between Electric Utilities And Consumers For Microgrid Utilization Based On A Systems Engineering Approach, Franklin E. Pacheco Chiguano

Open Access Theses

In recent years, the energy market has experienced important challenges in its structure and requirements of its actors, such as the necessity for more reliable electric service, energy efficiency, environmental care practices, and the incorporation of decentralized power generation based on distributed energy resources (DER). Given this context, microgrids offer several advantages to the grid and its actors. However, few microgrid projects have been implemented, and the participation of electric utilities is lower than the expected. Hence, this research explores how electric utility - customer interactions can accommodate mutual benefits for both parties through the proposal of a Microgrid Reference …

Asphalt Pavement Preservation Using Rejuvenating Fog Seals, Ammanuiel A. Kebede

Open Access Theses

Fog seal is a type of treatment that uses a diluted asphalt emulsion to seal and protect an existing asphalt surface from a variety of distresses. Fog seal is sprayed on top of an asphalt pavement surface to improve and protect it from further cracking and raveling. Rejuvenator is also a type of treatment that penetrates into the asphalt pavement and restores its original viscoelastic properties. Similarly, like fog seal, rejuvenators can be sprayed on top of an asphalt pavement surface. The use of rejuvenators has grown rapidly in the past decade. However, little is known about the actual effectiveness …

A Dynamic Stochastic Model For Converging Inbound Air Traffic, Jun Chen

Open Access Theses

Weather accounts for the majority of congestion in the National Airspace System which highlights the importance of addressing weather uncertainty to mitigate delays, and this paper presents an effort in this direction. Firstly, a new dynamic stochastic 0-1 Integer Programming (IP) model is proposed, which models the Single Airport Ground Holding Problem (SAGHP) with respect to uncertainty in the separation between flights instead of Airport Acceptance Rate (AAR) or landing capacity. Uncertainty in separation according to different weather conditions is represented through the scenario tree by using stochastic linear programming. Considering time separation constraints instead of AAR constraints, our model …

Heavy Vehicle Rollover Propensity At Roundabouts On Highspeed Roads, Thomas M. Hall

Open Access Theses

There is a recent trend of building roundabouts on high-speed roads, often with significant heavy vehicle traffic. With the increased presence of trucks on roundabouts, the issue of rollover has become a concern. Geometric features that allow excessive speed on the approach and entry have been connected to rollover, as well as sudden changes in crossfall and radius. However, the effect on the rollover threshold of changing the roundabout's circulatory superelevation is not fully understood. The impact of aggressive driving behaviors, as displayed by high driver speed far from the roundabout, as well as errors that are manifested by the …

Application Of Bayesian Networks In Consumer Service Industry, Yuan Gao

Open Access Theses

Gao, Yuan. M.S.I.E., Purdue University. December 2014. Application of Bayesian Networks in Consumer Service Industry. Major professor: Vincent G. Duffy The purpose of the present study is to explore the application of Bayesian networks in the consumer service industry to model causal relationships within complex risk factor structures using aggregate data. An analysis of the Hawaii tourism market was conducted to find out how visitor characteristics affect their behavior and experience as consumers during the trips, and influence the tourism market outcomes represented by measurable factors. Two hypotheses were proposed regarding the use of aggregate data and the influence of …

Designing Sustainable Mentoring Programs: Examining The Role Of Social Community In The Stem College Student Experience, Joi-Lynn Mondisa

Open Access Theses

In order to begin to understand how to design programs that promote community development and produce beneficial outcomes for community members, we must first define the elements and functions of such a community. In this thesis, I define social community as an environment where like-minded individuals engage indynamic, multidirectional interactions that facilitate social support . Using a human-integrated systems approach, I propose a social community model for STEM minority mentoring programs to understand how a community's design plays a role in the learning and enrichment of its members. The social community model is comprised of three main components: program …

Evaluation Of Lane Use Management Strategies, Chaitanya Paleti Siva Sai Krishna

Open Access Theses

The limited funding available for roadway capacity expansion and the growing funding gap, in conjunction with the increasing congestion, creates a critical need for innovative lane use management options. Various cost-effective lane use management strategies have been implemented in the United States and worldwide to address these challenges. However, these strategies have their own costs, operational characteristics, and additional requirements for field deployment. Hence, there is a need for systematic methodologies to evaluate lane use management strategies.

In this thesis, a systematic simulation-based methodology is proposed to evaluate lane use management strategies. It involves identifying traffic corridors that are suitable …

Capacity-Related Driver Behavior On Modern Roundabouts Built On High-Speed Roads, Shaikh Ahmad

Open Access Theses

The objective of this thesis was to investigate the factors that affect capacity-related driver behavior on modern roundabouts built on high-speed roads. The capacity of roundabouts is strongly affected by the behavior of drivers as represented by critical headway (critical gap) and follow-up headway (follow-up time). The effects of heavy vehicles (single-unit truck, bus, and semi-trailer) and area type (rural or urban) on roundabout capacity were investigated by comparing the critical headways for roundabouts located on high-speed and low-speed roads. The effects of nighttime conditions (in the presence of street lighting) were also considered. Data were collected using the Purdue …

The Hong Kong-Zhu Hai-Macau Bridge: Impacts On The Greater Pearl River Delta, Jun He

Open Access Theses

This research looks at the impacts of megaprojects on their host regions through a case study of the Hong Kong-Zhu Hai-Macau Bridge (HZMB). The purpose of this study is to analyze the potential economic impact of the HZMB on the region through existing data and stakeholder interviews. The research will specifically focus on megaprojects' impacts on tourism industry and economic development in general. The research results are aimed to address the four research objectives of the study, which are similarities and differences between the HZBM and other megaprojects, common issues involved in developing megaprojects, the future impacts of the HZMB …

Detecting Air Traffic Controller Interventions In Recorded Air Transportation System Data, Yul Kwon

Open Access Theses

In this study, I propose a systematic method of detecting aircraft deviation due to air traffic controller (ATC) intervention. The aircraft deviations associated with ATC interventions are detected using a heuristic algorithm developed from analyzing the actual positions of an aircraft to its filed flight plan when the aircraft trajectories were identified as having an encounter in a loss-of-separation incident. An actual (closed-loop) flight trajectory of the Cleveland Air Route Traffic Control Center (ZOB ARTCC) was collected from the FlightAware database. This was compared with the corresponding planned (open-loop) trajectory dataset generated by the Microsoft© Flight Simulator X (FSX). I …

Investigating Surface Performance Trade-Offs Of Unimpeded Taxiways, Tiffany T. Le

Open Access Theses

Optimizing usage of unimpeded taxiways is a near-term operational change to mitigate emission impact on aviation and increase efficiency at airports. An unimpeded taxiway is a path for an aircraft to taxi around an active runway. Unimpeded taxiways provide benefits such as increased departure throughput, increased safety, reduced surface congestion, more efficient taxi-in procedures, and thereby also yield environmental benefits. The goals of this work are to investigate the use of current taxiways, examine surface performance and fuel burn trade-offs, and to develop a decision-support model based on potential fuel savings of unimpeded taxiways. This study analyzes unimpeded taxiway use …

A Comparative Analysis Of An Original And A Post-Hoc Application Of Lean Six Sigma Methodology, Jin Qiu

Open Access Theses

Current society develops faster and faster every day with customers' demands increasing rapidly. Decreasing time for product development and enhancing customer satisfaction are becoming more significant. In the business world, there is no industry that could exist without an efficient supply chain. In the fierce competitive environment of today, the supply chain must address potential problems and risks that may exist and assure continuous improvement.

One common supply chain management practice in many industries is to apply lean methodology to the supply chain model in order to maximize the customers' value and eliminate waste. By eliminating waste, the process can …

A Lean Logistics Assessment Tool For Smes In The Manufacturing Sector, Diana Lorena Sanchez Ramirez

Open Access Theses

This study developed an assessment tool to rate the maturity of the current and desired states of lean logistics operations in small and medium enterprises. The tool consists of 48 best practices classified into 8 critical factors: Inventory, Transportation, Administration, Information Systems, Warehouse, Forecasting, Packaging and Supplier Network. Each of the best practices and critical factors were identified throughout a thorough literature review and comparative analysis between authors to define commonalities among them. Using gap analysis; this tool results in a SWOT matrix providing a roadmap for lean implementation. The resulting model was evaluated by subject matter experts in different …

Guidelines For Construction Companies To Decide Between Outsourcing And Self-Performing For Prefabricated Components, Sebastian Soto Ortiz

Open Access Theses

Prefabrication and modularization has been used in the construction industry for decades. It has recently made a resurgence worldwide providing increased productivity, safety, quality and construction schedule. This research has focused on the situation where a construction company has decided to use prefabrication and faces two possibilities, they either will self-perform or they will outsource the construction of the prefabricated components. The decision making process used by a construction company to determine whether to outsource or self-perform prefabricated components is examined and analyzed.

Prefabrication is an industrial process in which certain components are manufactured in a specialized facility. These items …

Increasing The Supply Of Affordable Housing In Urban India - Mumbai, Upasna Viswanathan

Open Access Theses

The need for housing in today's world is irrefutable. The growing population, accompanied with the fast pace of urbanization, are producing great housing demand, in urban areas in particular. This study focused on one segment of housing - affordable housing, in Mumbai, India, the demand for which has been on a steady rise over the past decade. Though traditionally the State was the provider of affordable housing, private sector has been increasingly involved in the segment, beginning the economic meltdown of 2008-2009. Yet there is a huge demand-supply gap that exists, which needs to be filled. The researcher looks at …

Retrofiting Lid Practices Into Existing Neighborhoods: Is It Worth It?, Timothy Wright

Open Access Theses

Low impact development (LID) practices are gaining popularity as a way to manage stormwater close to the source. This reduces infrastructure requirements and helps to maintain hydrologic processes close to predevelopment conditions. Studies have shown LID practices to be effective in reducing runoff and improving water quality. However, little has been done to aid decision makers in selecting the most effective practices for their needs and budgets.

To this end, the L-THIA LID model has been applied. Using readily available data sources, multiple scenarios can quickly be examined, and then analyzed to determine the cost of implementation and the approximate …

An Analysis On Causes Of Late Final Payment And Release Of Retainage: Electrical Subcontractors’ View, Xuejing Zhang

Open Access Theses

Using the survey approach, this study identified the underlying causes of late payments and release of retainage for electrical subcontractors, attempting to answer the questions, "What were the minimum, maximum and average delay days of final payment and release of retainage?", "What were the rank of factors in terms of significance on delaying final payment and release of retainage?", and "What were the rank of factors in terms of frequency on delaying final payment and release of retainage?" A survey questionnaire was developed and distributed to about 150 professionals in electrical subcontractors. 29 reports were collected. Based upon the analysis …

The Effect Of Job Performance Aids On Quality Assurance, Erik David Fosshage

Open Access Theses

Job performance aids (JPAs) have been studied for many decades in a variety of disciplines and for many different types of tasks, yet this is the first known research experiment using JPAs in a quality assurance (QA) context. The objective of this thesis was to assess whether a JPA has an effect on the performance of a QA observer performing the concurrent dual verification technique for a basic assembly task. The JPA used in this study was a simple checklist, and the design borrows heavily from prior research on task analysis and other human factors principles. The assembly task and …