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Filtering by: Creator Crown%2C David A. Remove constraint Creator: Crown%2C David A. Degree Field Civil Engineering Remove constraint Degree Field: Civil Engineering

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  • In situ measurement of the benthal oxygen requirements of tidal flat deposits

    Creator:
    Crook, Gene Ray
    Abstract:
    In situ light and dark planktonic and benthal respirometers were used to measure the oxygen requirements of Yaquina estuary water and benthal deposits. Respirometer devices were constructed so that actual conditions of mixing could be simulated and benthal deposit disturbance would be minimized. A mathematical model of a benthal respirometer...
    Resource Type:
    Masters Thesis
    Full Text:
    THE BENTHAL OXYGEN REQUIREMENTS OF TIDAL FLAT DEPOSITS Abstract approved: Dr. David A. Bella In

  • Development of a Reliability-Based Framework and Empirical Models for Justifying Allowable Chloride Limits and Quantifying Critical Input Variables for Predicting the Service Life of Reinforced Concrete Structures

    Creator:
    Shakouri Hassanabadi, Mahmoud
    Abstract:
    Significant progress has been made over the past 20 years in developing models to estimate the service-life of reinforced concrete systems. The basic understandings of the mechanisms that control the transport of ions and moisture in concrete systems have been well researched and models for determining corrosion initiation, specifically chloride-induced...
    Resource Type:
    Dissertation
    Full Text:
    September 22, 2017. Title: Development of a Reliability-Based Framework and Empirical Models for

  • Use of Flashing Lights in Traffic Safety of Vulnerable Road Users

    Creator:
    Ahmed, Ananna
    Abstract:
    Vulnerable road users, anyone interacting with the roadway facility without the protection of an automobile, experience greater risk for more severe crash outcomes. Multimodal roadway facilities often times provide less separation and more points of conflict between different types of road users. To promote vulnerable road user safety, transportation agencies...
    Resource Type:
    Dissertation
    Full Text:
    co-authors. In the third manuscript, Dr. David Hurwitz is a contributing co-author. ix

  • Critical Assessment of Chloride States and Quantities in Ordinary Portland and Specialty Cements

    Creator:
    Ahmed, Ahmed Abdulhaq
    Abstract:
    The constituent materials of concrete often contain chlorides. The presence of chlorides in sufficient amounts can disrupt the passive layer, also known as the passive film, that protects the reinforcing steel in concrete. This disruption can lead to premature corrosion of the reinforcing steel in concrete. To minimize the risk...
    Resource Type:
    Dissertation
    Full Text:
    Cements Abstract approved: ________________________________________________ David Trejo

  • Mathematical model of a phytoplankton community in a nitrate limited environment

    Creator:
    Grenney, William J.
    Abstract:
    Mathematical modeling of phytoplankton populations based on laboratory observations provides increased understanding of the interaction among the environmental and biological mechanisms. influencing growth dynamics. Such fundamental understanding is necessary to estimate the impact of man-made perturbations on natural population. A three-compartment mathematical model was developed to represent a phytoplankton population...
    Resource Type:
    Dissertation
    Full Text:
    Abstract approved: 'David A. Bella Mathematical modeling of phytoplankton populations based on laboratory

  • A study on the oxidation of sulfides in estuarine waters

    Creator:
    Korpalski, Thomas Paul
    Abstract:
    Waters of various salinities were secured from the Umpqua estuary, the Umpqua River, and the open ocean near the mouth of the estuary. The rate of oxidation of sulfides in these various waters was investigated to assess the potential longevity of free sulfides in estuarine waters. The rate of disappearance...
    Resource Type:
    Masters Thesis
    Full Text:
    STUDY ON THE OXIDATION OF SULFIDES IN ESTUARINE WATERS Abstract approved: Dr. David A. Bella Waters

  • Spatial, diel and seasonal variations in dissolved oxygen and temperature within a stratified lake

    Creator:
    Smith, Stanley Allan
    Abstract:
    Spatial, diel and seasonal variations in dissolved oxygen and temperature were measured in Triangle Lake, Oregon. Spatial dissolved oxygen and temperature variations measured in the stratified lake are presented to illustrate the horizontal uniformity of the lake and to demonstrate the applicability of the one dimensional assumption for sampling and...
    Resource Type:
    Masters Thesis
    Full Text:
    approved: Redacted for Privacy Dr. David A. Bella Spatial, diel and seasonal variations in dissolved

  • Modeling estuary pollution by computer simulation

    Creator:
    Grenney, William J.
    Abstract:
    A digital computer model was developed to simulate the time and space distribution of a dissolved pollutant in an estuary. The program is basically a one-dimensional finite-difference model, but two dimensions can be represented by attaching together several one-dimensional channels. The influence of convection, dispersion and decay are included in...
    Resource Type:
    Masters Thesis
    Full Text:
    : MODELING ESTUARY POLLUTION BY COMPUTER SIMULATION Abstract approved: Dr. David A. Belia A digital

  • Analysis of dichotomous response models for low-dose carcinogenic risk estimation

    Creator:
    Tabesh, Taraneh
    Abstract:
    Several dichotomous-response models of carcinogenesis are discussed and their implications for low-dose risk estimation are examined. In addition, a pharmacokinetic model incorporating non-linear kinetics is studied and the results are investigated with respect to multiple-pollutant exposures. None of these models appears to suggest the existence of "thresholds". The analysis of...
    Resource Type:
    Masters Thesis
    Full Text:
    estimation are examined. In addition, a pharmacokinetic model incorporating non- linear kinetics is studied

  • The effect of mixing on the oxygen uptake rate of estuarine bottom deposits

    Creator:
    Martin, Duane Collins
    Abstract:
    A study of the effect of mixing on the oxygen uptake rate of estuarine bottom deposits is presented. The method of study involved the mixing of samples of bottom deposits with the overlying water to result in concentrations of suspended matter in the same order as observed in the estuary....
    Resource Type:
    Masters Thesis
    Full Text:
    Professor Dr. David A. Bella for being a constant source of assistance and inspiration. My wife, Dottie