Analytical and Numerical Investigation of a Mechanically Stabilized Earth Wall on I-15

This dissertation is the culmination of extensive research into the behavior of a 11 mechanically stabilized earth (MSE) wall at 1-15 and 3600 South in Salt Lake City, Utah. The wall is about 30 ft tall and is constructed on a compressible, soft clay foundation. Research on this project has included extensive instrumentation and monitoring of stresses and deformations in the wall and its foundation, a study of the effects of drilling and sampling method on disturbance of samples, and extensive laboratory testing to determine strength and deformation properties of soils at the site. The results of these portions of the project are summarized. All of this work has been used to develop and calibrate an analytical model of the MSE wall. This dissertation presents this analytical model. The analytical model of this wall is a valuable and powerful tool to understand the behavior of tall MSE walls on compressible foundations. By using such a model, the effects of pore pressure dissipation during construction can be evaluated. This allows for accurate evaluation of the stability of the embankment during construction and long term for any construction sequence. The model can be used to evaluate soil reinforcement interaction and to evaluate different reinforcement configurations. This research contains discussions of the soil model that was developed for Bonneville clay, a comparison between measured and calculated deformations in the wall foundation, the time-settlement behavior of the wall, soil-reinforcement interactions, and stability evaluations, as well as a comparison of traditional slope stability analysis results to the finite element results obtained from this model

Performance Monitoring of a Bridge Abutment Spread Footing From Construction Through Service

The use of spread footings over compressible soils is becoming more common for Minnesota Department of Transportation bridges as technologies improve to better predict, mitigate, and evaluate settlement. In August of 2011 the north abutment of a new bridge crossing I-494 was constructed over compressible soils following a soil fill preload, designed to reduce the foundation settlement from several inches to less than one inch, to meet project requirements. Spread footing foundations are seldom outfitted with instrumentation; adequate performance is frequently assumed based on the decision to use shallow foundations. Here, a monitoring plan was developed to validate the preloading technique for mitigating otherwise unacceptable deformations, assess the efficacy of shallow foundation monitoring methods, and gain a better understanding of shallow foundation behavior with time. Instrumentation consisted of two earth pressure cells, a horizontal MEMS SAA deformation monitoring array, and four optical survey reflectors which were installed during the construction of the foundation and abutment wall. During the course of construction, portions of the abutment backfill soil volume were placed and removed to accommodate the construction of the bridge deck and the adjacent wall footings. The effect of the various loading and unloading conditions was observed on the sensors. The abutment foundation performance over the construction timeline is discussed, including apparent loading, deflection, and rotation. The data from the manually observed survey targets is compared to the automated data from the SAA and earth pressure cells

Temperature and electrolyte optimization of the α-hemolysin latch sensing zone for detection of base modification in double-stranded DNA

The latch region of the wild-type protein pore α-hemolysin (α-HL) constitutes a sensing zone for individual abasic sites (and furan analogs) in double-stranded DNA (dsDNA). The presence of an abasic site or furan within a DNA duplex, electrophoretically captured in the α-HL vestibule and positioned at the latch region, can be detected based on the current blockage prior to duplex unzipping. We investigated variations in blockage current as a function of temperature (12–35°C) and KCl concentration (0.15–1.0 M) to understand the origin of the current signature and to optimize conditions for identifying the base modification. In 1 M KCl solution, substitution of a furan for a cytosine base in the latch region results in an ∼8 kJ mol−1 decrease in the activation energy for ion transport through the protein pore. This corresponds to a readily measured ∼2 pA increase in current at room temperature. Optimal resolution for detecting the presence of a furan in the latch region is achieved at lower KCl concentrations, where the noise in the measured blockage current is significantly lower. The noise associated with the blockage current also depends on the stability of the duplex (as measured from the melting temperature), where a greater noise in the measured blockage current is observed for less stable duplexes

Energetics of base flipping at a DNA mismatch site confined at the latch constriction of α-hemolysin

Unique, two-state modulating current signatures are observed when a cytosine-cytosine mismatch pair is confined at the 2.4 nm latch constriction of the [small alpha]-hemolysin ([small alpha]HL) nanopore. We have previously speculated that the modulation is due to base flipping at the mismatch site. Base flipping is a biologically significant mechanism in which a single base is rotated out of the DNA helical stack by 180[degree]. It is the mechanism by which enzymes are able to access bases for repair operations without disturbing the global structure of the helix. Here, temperature dependent ion channel recordings of individual double-stranded DNA duplexes inside [small alpha]-HL are used to derive thermodynamic ([capital Delta]H, [capital Delta]S) and kinetic (Ea) parameters for base flipping of a cytosine at an unstable cytosine-cytosine mismatch site. The measured activation energy for flipping a cytosine located at the latch of [small alpha]HL out of the helix (18 +/- 1 kcal mol-1) is comparable to that previously reported for base flipping at mismatch sites from NMR measurements and potential mean force calculations. We propose that the [small alpha]HL nanopore is a useful tool for measuring conformational changes in dsDNA at the single molecule level

How the Faculty Fellows Program Supports Faculty\u27s Scholarly Innovations and Teaching Innovations

This panel discussion will feature Dr. Aaron Budge and Dr. Karen Lybeck, who will discuss CETL\u27s Faculty Fellows program. They will also discussthe benefits for faculty who engaging in these programs and how the programcan support faculty member\u27s Professional Development Plans and Reports.Lastly, they will discuss the benefits for student success and our campuscommunity

An Ocularist\u27S Approach To Human Iris Synthesis

A methodology used in the field of ocular prosthetics is translated into a toolkit for creating and rendering realistic looking irises. The method creates patterns and colors that match existing human irises. The method mimics the ocularist\u27s approach by adding one layer at a time to the model and rendering an intermediate result

An Ocularist's Approach to Human Iris Synthesis

Human irises gain their appearance from a layered and highly complex structure that is difficult to model and render with conventional techniques. We present an approach that uses domain knowledge from the field of ocular prosthetics. In that field, ocularists create an artificial iris by painting many simple semi-transparent layers. We translate this methodology into a simple and effective toolkit which can be used to create and render realistic looking irises

Determining what works in the treatment of PTSD

Many researchers accept that trauma-focused treatments are superior to non-trauma focused treatments for Post-Traumatic Stress Disorder (PTSD). However, Benish, Imel, and Wampold (2008) recently published a meta-analysis of clinical trials directly comparing 'bona fide' PTSD treatments that failed to reject the null hypothesis that PTSD treatments are similarly effective. They concluded that the results of previous meta-analysis may have been influenced by several confounds, including the use of control treatments, to make conclusions about the relative efficacy of specific PTSD treatments. Ehlers et al. (2010) claim that the selection procedures of the Benish et al. meta-analysis were biased and cite results from individual studies and previous meta-analyses that suggest trauma-focused psychological treatments are superior to non-trauma focused treatments. We first offer a review and justification of the coding criteria and procedure used in Benish et al. In addition, we discuss the appropriateness of utilizing treatments designed to control for non-specifics or common factors such as 'supportive therapy' for determining the relative efficacy of specific PTSD treatments. Finally, we note several additional confounds, such as therapist effects, allegiance, and alteration of legitimate protocols, in PTSD research and describe conceptual problems involved in the classification scheme used to determine the "trauma focus" of interventions, which lead to inappropriate conclusions about what works in the treatment of PTSD