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  • Thesis

  • Assessing seismic collapse safety of modern reinforced concrete moment frame buildings

    • Authors: Haselton, Curt B. (2006)

  • A primary goal of seismic design requirements of building codes is to protect the life safety of building inhabitants during extreme earthquakes. First and foremost, this requires that the likelihood of structural collapse be at an acceptably low level. However, building codes and standards are empirical in nature, which results in the collapse safety of new buildings not being well understood. In this research, we develop the tools and methods to quantitatively assess the collapse risk of reinforced concrete (RC) special moment frame (SMF) buildings designed by the 2003 International Building Code. While RC SMF buildings are the focus on this study, the methodology and many of the tools can be used to assess any type of structural system. This rigorous analytical collapse assessme...
  • Thesis

  • Behavior of reinforced concrete girders under cyclic torsion and torsion combined with shear: Experimental investigation and analytical models

    • Authors: Greene, Gary Gordon, Jr. (2006)

  • Torsion can be a significant action in many structural members that are part of civil engineering infrastructure. Gravity loads can induce torsional stresses in curved bridges and spandrel beams. Seismic loads can induce cyclic torsion combined with other actions in the beams and columns of bridges with outriggers. Reliable models are needed to predict the effect of torsional stresses on a reinforced concrete (RC) member's hysteretic load-deformation response, and also on the monotonic behavior at service and ultimate load levels. Little previous research has focused on the hysteretic behavior of RC members under cyclic torsion and torsion combined with other actions. This research study was intended to improve the understanding of the behavior of such members and provide analytical...
  • Thesis

  • Characterizing grain-scale availability of aromatic hydrocarbons in MGP site soils and assessment of the impact on the dynamics of soil and pore water concentration during and after remediation

    • Authors: Luper, Robert Bryan (2006)

  • To predict groundwater concentration levels which emanate from a contaminated source, early release models assumed local equilibrium partitioning. As the validity of this assumption has been questioned, models have been developed which incorporate kinetic release. To further this work, two complementary studies were performed. The first involved applying developed laboratory and analytical techniques for measuring availability during the remediation of an existing contaminated site. The second involved the application of a two-site equilibrium/rate-limited release model to illustrate the impact of specific degrees of limited availability. For the first study, as an initial measure of contaminant availability, short-term batch tests were performed before, during and after the remedi...
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  • Colloidal silica transport mechanisms for passive site stabilization of liquefiable soils

    • Authors: Lin, Yuanzhi (2006)

  • Passive site stabilization is a new ground improvement technique to mitigate earthquake-induced liquefaction risk at developed sites. It consists of long-distance permeation grouting in which colloidal silica grout is slowly injected into the soil through wells located at the up gradient edge of the treatment area. The stabilizer is transported to the treatment area by the groundwater. Transport is augmented by extraction wells at the down gradient edge of the treatment area. The practical feasibility of this technique depends on the ability to deliver the grout to the liquefiable soil formation efficiently and in an adequate concentration to stabilize the soil. The purpose of this research was to determine if colloidal silica grout can be delivered uniformly over long distances in ...
  • Thesis

  • Comparative analyses of geophysical methods for determining shear wave velocity of soils

    • Authors: Thitimakorn, Thanop (2006)

  • The Missouri Department of Transportation (MoDOT) routinely acquires seismic cone penetrometer (SCPT) shear wave velocity control as part of the routine investigation of soils at highway structures or other geotechnical sites within the Mississippi Embayment. In an effort to ensure their geotechnical investigations are as effective and efficient as possible, the SCPT tool and several available alternatives (crosshole: CH; multichannel analysis of surface waves: MASW; and refraction microtremor: ReMi) were evaluated and compared on the basis of the interpretation of processed field data acquired at two test sites in the Poplar Bluff area, southeast Missouri. These four methods for determining the shear wave velocity of soils were subsequently ranked in terms of accuracy, functionalit...
  • Thesis

  • Computational methods for automatic image registration

    • Authors: Zuliani, Marco (2006)

  • Image registration is the process of establishing correspondences between two or more images taken at different times, from different viewpoints, under different lighting conditions, and/or by different sensors, and aligning them with respect to a coordinate system that is coherent with the three dimensional structure of the scene. Once feature correspondences have been established and the geometric alignment has been performed, the images are combined to provide a representation of the scene that is both geometrically and photometrically consistent. This last process is known as image mosaicking. The primary contribution of this research is the development of computational frameworks that tackle in a general and principled way the problems arising in the construction of an image r...
  • Thesis

  • Computational study of amyloid beta protein in implicit and explicit solvent models: Probing the initial stages of aggregation

    • Authors: Tarus, Bogdan (2006)

  • It has been proposed that the amyloid ,3-protein (A/3-protein) plays a crucial role in the development of Alzheimer's Disease (AD). This dissertation presents the results of computational studies of the initial stages of A3-protein association. The objective of this work was to determine the stability and role of the A/3-protein monomers and low-order oligomers as metastable intermediates on the pathway for formation of larger aggregates and fibrils. A protocol based on shape complementarity is used to generate an assortment of possible dimer structures of the A310_35-protein congener. The ensemble of dimer structures are evaluated using rapidly computed estimates of the desolvation and electrostatic interaction energies to identify a putative stable dimer structure. Using the umbre...
  • Thesis

  • Cranial neural crest cell migration in the avian embryo and the roles of Eph-A4 and ephrin-A5

    • Authors: Lu, Carole Chih-Chen (2006)

  • The neural crest is a transient population of cells that migrate away from the dorsal neural tube in the vertebrate embryo. As the developing hindbrain constricts into rhombomeres, cranial neural crest cells migrate in three discrete streams adjacent to even-numbered rhombomeres, rhombomere 2 (r2), r4, and r6. To test the role of intrinsic versus extrinsic cues in influencing an individual cell's trajectory, we implanted physical barriers in the chick mesoderm, distal to emerging neural crest cells (NCCs). We analyzed spatio-temporal dynamics as NCCs encountered and responded to the barriers by using time-lapse confocal microscopy and cell tracking analysis. The majority of NCCs were able to overcome physical barriers. Even though the lead cells become temporarily blocked by a barr...