Constitutive modelling of the behaviour of clays under cyclic loading

Includes bibliography.This research work involved the implementation of a constitutive model based on plasticity theory to model the behaviour of a clay under cyclic loading. The modelling must be based on an understanding of the soil response and the critical state theory provides a description of the soil response which then be formulated in terms of plasticity theory. A literature review showed that there is a shortage of information on the behaviour of soils under cyclic loading. Constitutive models for 'cyclic loading are discussed to compare the predictions and thus select a model

Analysis of control concepts for gas and shaft-coupled V/STOL aircraft lift fan systems

For lift-fan powered V/STOL aircraft, two unconventional propulsion system types were proposed. The first type uses fans connected by hot gas ducting, and the second type uses fans connected by cross shafting. An analytical study identified the basic steady-state and dynamic characteristics for each type of system. For the gas-coupled system, the control concepts analyzed were variable-area fan turbines and throttling valves in the ducting. For the shaft-coupled system, the control concepts analyzed were variable-pitch fans and variable fan inlet guide vanes. All of these concepts are capable of meeting V/STOL aircraft control moment and transient response requirements when appropriate propulsion controls are used

Propulsion system mathematical model for a lift/cruise fan V/STOL aircraft

A propulsion system mathematical model is documented that allows calculation of internal engine parameters during transient operation. A non-realtime digital computer simulation of the model is presented. It is used to investigate thrust response and modulation requirements as well as the impact of duty cycle on engine life and design criteria. Comparison of simulation results with steady-state cycle deck calculations showed good agreement. The model was developed for a specific 3-fan subsonic V/STOL aircraft application, but it can be adapted for use with any similar lift/cruise V/STOL configuration

Owner Reported Outcomes on Two Psychometric Tests Do Not Predict Behavior on a Spatial Discounting Test.

Impulsivity is an inability to control inappropriate responses to stimuli in the environment. It refers to an inability to inhibit an action or to delay gratification for an immediate small reward versus a deferred large reward. Poor impulse control in dogs is a leading cause of owner relinquishment, rejection from assistance- and working-dog programs, and returns to shelter and foster care. The ability to reliably identify dogs who engage in impulsive behavior would improve these dogs’ welfare by facilitating appropriate interventions in a timely manner. To investigate if the tendency of impulsive choice could be predicted by available psychometric tests, twenty-four dog/handler teams were recruited to participate in this study. All teams were composed of veterinary professionals employed at a single community animal hospital and their dogs. Handlers completed both the Canine Behavioral Assessment & Research Questionnaire (C-BARQ) and the Dog Impulsivity Assessment Scale (DIAS) psychometric tests. All dog/handler teams then completed a spatial discounting test, assessing their dog’s ability to inhibit the choice of a close small food reward versus a more distant larger food reward. Twenty-one C-BARQ and DIAS sub-scales were found to have a statistically significant association. After performing a Bonferroni error correction calculation, two sets of pairwise associations related to arousability emerged as highly correlated and significant. However, we did not see a statistically significant association between C-BARQ, or DIAS sub-scales and maximum distance traveled in the spatial discounting test. This outcome raises the question of whether the attribution of impulsivity based on an owner reported questionnaire is subject to bias. Additionally, the spatial discounting test may not be an appropriate measure of impulsivity as a single test. The conclusion of this study suggests that veterinarians must carefully consider the limitations of behavioral diagnostic tests and be aware that erroneous results can influence welfare outcomes for companion dogs

Sustainable Development and Ending Hunger: Connecting Students to Global Issues

This presentations will focus on connecting students to the UN Sustainable Development Goals through both student and faculty perspectives. The presentation is based on a collaboration between a McNair Scholar and her faculty mentor. The presenters will explore ways in which connections between the university and community partners may enhance students\u27 awareness of global issues and specifically Goal 2 of the UN Sustainable Development Goals