Social and Behavioral Sciences Commons^™

Dual Enrollment Participation In The United States: Findings From The High School Longitudinal Study Of 2009, Luis Eduardo Rivera

Open Access Theses & Dissertations

Today, dual enrollment programs are ubiquitous in the United States' secondary educational system. As a form of accelerated coursework, policy makers and school districts push dual enrollment as a means to improve college readiness and attainment. This paper studies the composition and characteristics of dual enrollment participants in the United States. Employing the High School Longitudinal Study of 2009 restricted dataset, three discrete logistic models are created to estimate the probability of a high school student participating in any dual enrollment coursework across the United States. The results from these models suggest that gender, prior academic achievement, and family socioeconomic …

Trade Cluster Impacts On Southern Border Transportation Costs, Ernesto Duarte Ronquillo

Open Access Theses & Dissertations

This Thesis develops a fixed effect model to analyze the impact of trade clusters on transportation costs. CIF/FOB ratios are utilized as the measures for transportation costs. Grubel-Lloyd and Herfindahl-Hirschman indexes are utilized as variables that identify trade clusters. The focus of this study encompasses four custom districts (El Paso, Laredo, Nogales, and San Diego) located on the southern border of the United-States over the period of 1995-2015. Driscoll-Kraay robust standard errors are calculated for each estimated model. The 9/11 terrorist attack effects are taken into account in the fixed effect model. Empirical results suggest that trade clusters have a …

Analysis Of Infectious Diseases Screening Systems For Transatlantic Air Passengers, Lukas Gold

Open Access Theses & Dissertations

Since transportation systems, especially air transportation, have the potential to spread infectious diseases (e.g. Ebola, SARS) quickly across large geographical area through its users, passenger health screening systems installed at the airports can help to slow down the international spread.

This Thesis identifies and tests health screening system designs using discrete event simulation. The three objectives are: (1) to provide the necessary background regarding the diseases and screening technologies, (2) to create models of an air transportation network in a simulation software, and (3) to conduct simulation experiments, analyze and interpret the results including the formulation of recommendations for decision …

Crash Rate As A Function Of Access Point Density And Traffic Flow, George Pinal

Open Access Theses & Dissertations

High crash rates on U.S. highways results in a considerable loss of human and economic resources. It is estimated that the U.S. loses about $10 billion every year in motor vehicle crashes in terms of fatalities, injuries, and property damage. Demand for access points from highways to properties has steadily increased due to rapid growth in local economies creating thereby compromises between accessibility and mobility or capacity and safety. On the other hand, the availability of access is essential to residential and commercial developments and often occurs at the cost of safety and traffic operations. This often directs the need …

Evaluation Of Mechanical Parameters Of Contaminated Road Base And Railway Ballast, Prajwol Tamrakar

Open Access Theses & Dissertations

This Dissertation comprises two topics in the area of transportation geotechnics that focus on the evaluation of stiffness parameters of contaminated road base and railway ballast. The abstracts of these two studies are provided in the following two paragraphs.

The performance of a flexible pavement depends on the mechanical characteristics of its unbound granular base layer. The mechanical characteristics such as stiffness and deformation resistance depend on many factors such as the material gradation, fines content, moisture content, physical properties of coarse aggregate and more. The base materials are often contaminated by the excessive fines that is caused by improper …

Development Of An Alternative Laboratory Testing Procedure For Tensile Characterization Of Cement Stabilized Base Layers, Jose Antonio Tarin

Open Access Theses & Dissertations

Proper characterization of the fatigue performance of stabilized materials in the laboratory is an integral component of the structural design of stabilized layers in multi-layer pavements. The new mechanistic pavement design protocols require modulus of rupture of the stabilized base layers as an input to the fatigue performance models. This study discusses the practical and theoretical discrepancies associated with the traditional tensile strength tests, and provides an alternative testing procedure for the determination of the tensile strength of the stabilized materials in the laboratory. To achieve this objective, a full factorial laboratory experiment design consisted of four aggregate sources with …

Impact Of Reclaimed Asphalt Pavement And Recycled Asphalt Shingles On Laboratory And Field Performance Of Texas Asphalt Concrete Pavements, Berenice Salaices Gomez

Open Access Theses & Dissertations

The use of recycled materials in Asphalt Concrete (AC) mixes is highly promoted in the transportation industry. Recycled materials minimize the use of virgin materials, reduce the consumption of resources, and cut costs for new construction or rehabilitation projects. The incorporation of Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) in the AC mixture is promoted as long as equal or improved performance is achieved. The Texas Department of Transportation (TxDOT) is currently placing asphaltic concrete (AC) mixes that are lasting less than their expected performance life when recycled materials are used.

The objective of this Thesis is to …