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Teenagers' Mode Choice To And From School And Technology Use For Transportation: Analysis Of Students From Five High Schools In Vermont And California, Paola Rekalde Aizpuru

Graduate College Dissertations and Theses

The carhops and drive-ins of the 1950s are symbolic of the freedom that the automobile has granted Americans. What the general public has gained from the automobile, however, may come at the expense of independent mobility and choices for today's adolescents, particularly those not yet old enough to drive or those from lower income families. Sprawl land use development patterns and limited transportation choices in most American cities often hold teenagers and their chauffeuring parents captive to the automobile. At the same time, information and communication technology is fast evolving and changing the ways in which teenagers live, interact, and …

Characterization Of Fillite As A Planetary Soil Simulant In Support Of Rover Mobility Assessment In High-Sinkage/High-Slip Environments, Michael Edwards

Graduate College Dissertations and Theses

This thesis presents the results of a research program characterizing a soil simulant called Fillite, which is composed of alumino-silicate hollow microspheres harvested from the pulverized fuel ash of coal-fired power plants. Fillite is available in large quantities at a reasonable cost and it is chemically inert. Fillite has been selected by the National Aeronautics and Space Administration (NASA) Glenn Research Center to simulate high-sinkage/high-slip environment in a large test bed such as the ones encountered by the Spirit rover on Mars in 2009 when it became entrapped in a pocket of soft, loose regolith on Mars. The terms high-sinkage …

Characterization Of Real-World Particle Number Emissions During Re-Ignition Events From A 2010 Light-Duty Hybrid-Electric Vehicle, Matthew Beach Conger

Graduate College Dissertations and Theses

Despite the increasing popularity of hybrid-electric vehicles (HEVs), few studies have quantified their real-world particle emissions from internal combustion engine (ICE) re-ignition events (RIEVs). RIEVs have been known to occur under unstable combustion conditions which frequently result in particle number emission rates (PNERs) that exceed stabilized engine operation. Tailpipe total PN (5 to 560 nm diameter) emission rates (#/s) from a conventional vehicle (CV) and hybrid electric vehicle (HEV) 2010 Toyota Camry were quantified on a 50 km (32 mi) route over a variety of roadways in Chittenden County, Vermont using the Total On-board Tailpipe Emissions Measurement System (TOTEMS). While …

Bayesian Filtering In Nonlinear Structural Systems With Application To Structural Health Monitoring, Kalil Erazo

Graduate College Dissertations and Theses

During strong earthquakes structural systems exhibit nonlinear behavior due to low-cycle fatigue, cracking, yielding and/or fracture of constituent elements. After a seismic event it is essential to assess the state of damage of structures and determine if they can safely resist aftershocks or future strong motions. The current practice in post-earthquake damage assessment relies mainly on visual inspections and local testing. These approaches are limited to the ability of inspectors to reach all potentially damaged locations, and are typically intended to detect damage near the outer surfaces of the structure leaving the possibility of hidden undetected damage. Some structures in …

Organic Chemical Characterization Of Primary And Secondary Biodiesel Exhaust Particulate Matter, John Kasumba

Graduate College Dissertations and Theses

Biodiesel use and production has significantly increased in the United States and in other parts of the world in the past decade. This change is driven by energy security and global climate legislation mandating reductions in the use of petroleum-based diesel. Recent air quality research has shown that emission of some pollutants such as CO, particulate matter (PM), SO2, hydrocarbons, and carcinogenic polycyclic aromatic hydrocarbons (PAHs) is greatly reduced with biodiesel. However, studies have also shown that some unregulated emissions, such as gas-phase carbonyls, are increased with biodiesel combustion. Very limited research has been done to investigate the particle-phase carbonyl …

The Effect Of Biodiesel Blends On Particle Number Emissions From A Light Duty Diesel Engine, Tyler Samuel Feralio

Graduate College Dissertations and Theses

Numerous studies have shown that respirable particles contribute to adverse human health outcomes including discomfort in irritated airways, increased asthma attacks, irregular heartbeat, non-fatal heart attacks, and even death. Particle emissions from diesel vehicles are a major source of airborne particles in urban areas. In response to energy security and global climate regulations, the use of biodiesel as an alternative fuel for petrodiesel has significantly increased in recent years. Particle emissions from diesel engines are highly dependent on fuel composition and, as such, the increased use of biodiesel in diesel vehicles may potentially change the concentration, size, and composition of …

Geomechanical Characterization Of Marcellus Shale, Rafael Villamor Lora

Graduate College Dissertations and Theses

Given their potential applications for a number of engineering purposes, the geomechanics of shale reservoirs is becoming one of the most important issues in modern geomechanics. Borehole stability modeling, geophysics, shale oil and shale gas reservoirs, and underground storage of CO2 and nuclear waste are some of these potential applications to name a few. The growing interest in these reservoirs, as a source for hydrocarbons production, has resulted in an increasing demand for fundamental material property data.

Laboratory analysis and constitutive models have shown that rock elastic and deformational properties are not single-value, well-defined parameters for a given rock. Finding …

Evaluation Of Key Geomechanical Aspects Of Shallow And Deep Geothermal Energy, Robert Alexander Caulk

Graduate College Dissertations and Theses

Geothermal energy has become a focal point of the renewable energy revolution. Both shallow and deep types of geothermal energy have the potential to offset carbon emissions, reduce energy costs, and stimulate the economy. Before widespread geothermal exploration and exploitation can occur, both shallow and deep technologies require improvement by theoretical and experimental investigations. This thesis investigated one aspect of both shallow and deep geothermal energy technologies. First, a group of shallow geothermal energy piles was modeled numerically. The model was constructed, calibrated, and validated using available data collected from full-scale in-situ experimental energy piles. Following calibration, the model was …

Phosphate Removal And Recovery From Wastewater By Natural Materials For Ecologically Engineered Wastewater Treatment Systems, Daniel Thomas Curran

Graduate College Dissertations and Theses

Eutrophication due to excess loading of phosphorus (P) is a leading cause of water quality degradation within the United States. The aim of this study was to investigate P removal and recovery with 12 materials (four calcite varieties, wollastonite, dolomite, hydroxylapatite, eggshells, coral sands, biochar, and activated carbon. This was accomplished through a series of batch experiments with synthetic wastewater solutions ranging from 10-100 mg PO₄-P/ L. The results of this study were used to establish large-scale, calcite-based column filter experiments located in the Rubenstein School of Environment and Natural Resources' Eco-Machine. Influent and effluent wastewater samples were routinely collected …