A thesis submitted to the Faculty of Geography, Archaeology, and Environmental Studies University of the Witwatersrand, Johannesburg, in fulfilment of the requirements of the degree of Doctor of Philosophy. 2015. / An imaging DOAS instrument, along with in situ trace-gas and aerosol instrumentation was deployed on board a research aircraft over the Highveld region of South Africa, to make regional-scale measurements of nitrogen dioxide (NO2). The presence of a “hotspot” of NO2 over the Highveld is confirmed. Case-study estimates of NO2 emission flux were made downwind of a power station (10 tons.hr−1), a petrochemical plant (36 tons.hr−1) and the entire Highveld region (395 tons.hr−1). Vertical profile measurements were used to develop scenarios for a radiative transfer sensitivity study. From this, suitable air-mass factors for the DOAS measurements were determined. Comparisons between the airborne DOAS and satellite instruments show a good agreement where the spatial scales of the satellite ground pixels and the features in the two-dimensional trace-gas distribution are matched. A long-term record of satellite data was analysed. Analysis of radiative transfer revealed a possible artefact in the adjacent positive and negative trends evident on the Highveld. A correction to the satellite record for a seasonal bias was made, and found to be important over biomass burning regions in Angola and Zambia. Spatial features in a seasonal model of the satellite record are shown to correspond with known urban, industrial and biomass burning sources in the region. Signatures of soil emissions are also detected.

Most of recent studies indicate that people are negatively predisposed toward utilizing autonomous systems. These findings highlight the necessity of conducting research to better understand the evolution of trust between humans and growing autonomous technologies such as self-driving cars (SDC). This research therefore presents a new approach for real-time trust measurement between passengers and SDCs. We utilized a new structured data collection approach along with a virtual reality (VR) SDC simulator to understand how various autonomous driving scenarios can increase or decrease human trust and how trust can be re-built in the case of incidental failures. To verify our methodology, we designed and conducted an empirical experiment on 50 human subjects. The results of this experiment indicated that most subjects could rebuild trust during a reasonable timeframe after the system demonstrated faulty behavior. Furthermore, we discovered that the cultural background and past trust-related experiences of the subjects affect how they lose or regain their trust in SDCs. Our analysis showed that this model is highly effective for collecting real-time data from human subjects and lays the foundation for more-involved future research in the domain of human trust and autonomous driving. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

by Lo, Chi Ho Chester. / Title also in Chinese characters. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 159-163). / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.iv / List of Figures --- p.vii / List of Tables --- p.xii / Chapter Chapter One --- Introduction --- p.1 / Chapter Chapter Two --- Domain Theory --- p.8 / Chapter 2.1 --- Energies in Magnetic Domain Structure --- p.8 / Chapter 2.2 --- Domains in Iron and Nickel --- p.13 / Chapter 2.3 --- Magnetization Process --- p.15 / Chapter 2.4 --- Effect of Applied Stress --- p.19 / Chapter Chapter Three --- Magnetoacoustic Emission --- p.25 / Chapter 3.1 --- Models of MAE --- p.25 / Chapter 3.1.1 --- Discontinuous Wall Motion --- p.25 / Chapter 3.1.2 --- Displacement Model --- p.28 / Chapter 3.1.3 --- DW Creation and Annihilation --- p.30 / Chapter 3.1.4 --- Combined Model of MAE --- p.31 / Chapter 3.2 --- MAE and Magnetic Induction --- p.34 / Chapter 3.2.1 --- Eddy Current Shielding --- p.34 / Chapter 3.2.2 --- Magnetic Reluctance Calculation --- p.35 / Chapter Chapter Four --- Experiments / Chapter 4.1 --- Instrumentation --- p.40 / Chapter 4.1.1 --- Introduction --- p.40 / Chapter 4.1.2 --- Basic Setup --- p.41 / Chapter 4.1.3 --- Arrangement for Stress Measurement --- p.46 / Chapter 4.1.4 --- Specimen Preparation --- p.43 / Chapter 4.2 --- Methodology / Chapter 4.2.1 --- The Fundamental Study of MAE --- p.53 / Chapter 4.2.1.1 --- Effects of Demagnetizing and Stray Fields on MAE --- p.53 / Chapter 4.2.1.2 --- Dependence of MAE on Frequency of Applied Field --- p.55 / Chapter 4.2.1.3 --- Dependence of MAE on Specimen Thickness and Width --- p.55 / Chapter 4.2.2 --- Stress Measurement --- p.58 / Chapter 4.2.2.1 --- Effect of Uniaxial Stress on MAE --- p.58 / Chapter 4.2.2.2 --- Effect of Biaxial Stresses on MAE --- p.58 / Chapter 4.2.3 --- Defect Detection --- p.60 / Chapter 4.2.3.1 --- Nickel --- p.60 / Chapter 4.2.3.2 --- Mild Steel --- p.61 / Chapter Chapter Five --- Results and Discussion / Chapter 5.1 --- Effects of Demagnetizing and Stray Fields on MAE --- p.63 / Chapter 5.1.1 --- MAE Profiles --- p.63 / Chapter 5.1.2 --- Magnetic Reluctance Calculation --- p.68 / Chapter 5.1.3 --- Effect of Annealing --- p.74 / Chapter 5.1.3.1 --- Experimental Results --- p.74 / Chapter 5.1.3.2 --- Discussion --- p.77 / Chapter 5.1.3.3 --- Magnetic Reluctance Calculation --- p.78 / Chapter 5.2 --- Dependence of MAE on Frequency of Applied Field --- p.83 / Chapter 5.2.1 --- Experimental Results --- p.83 / Chapter 5.2.2 --- Theoretical Consideration --- p.88 / Chapter 5.3 --- Dependence of MAE on Specimen Thickness and Width --- p.96 / Chapter 5.3.1 --- Experimental Results --- p.96 / Chapter 5.3.2 --- Theoretical Consideration --- p.99 / Chapter 5.4 --- Effects of Uniaxial and Biaxial Stresses on MAE --- p.107 / Chapter 5.4.1 --- Effect of Uniaxial Stress --- p.107 / Chapter 5.4.1.1 --- Experimental Results --- p.107 / Chapter 5.4.1.2 --- Discussion --- p.116 / Chapter 5.4.2 --- Effect of Biaxial Stresses --- p.120 / Chapter 5.4.2.1 --- Study on Mild Steel Specimen --- p.120 / Chapter 5.4.2.2 --- Study on Nickel Specimen --- p.132 / Chapter 5.5 --- Defect Detection by MAE --- p.137 / Chapter 5.5.1 --- Study on Nickel Specimen --- p.137 / Chapter 5.5.1.1 --- Experimental Results --- p.137 / Chapter 5.5.1.2 --- Discussion --- p.140 / Chapter 5.5.2 --- Study on Mild Steel Specimen --- p.142 / Chapter 5.5.2.1 --- Experimental Results --- p.142 / Chapter 5.5.2.2 --- Discussion --- p.151 / Chapter Chapter Six --- Conclusions and Suggestions for Further Studies --- p.153 / References --- p.159

Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / Includes bibliographical references. / M.S.

Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

With the advent of the new high Tc superconductors, liquid nitrogen will be one of the preferred cryogens used to cool these materials. Consequently, a more thorough understanding of the heat transfer characteristics of liquid nitrogen is required. In our investigations we examine the transient heating characteristics of liquid nitrogen to states of nucleate and film boiling under different liquid flow conditions. Using a platinum hot wire technique, it is verified that there is a premature transition to film boiling in the transient case at power levels significantly lower than under steady state nucleate boiling conditions. It is also shown that the premature transition can be reduced or eliminated depending on the flow velocity.

An energy analyzer for electron beams, based on a retarding-potential method, has been studied both experimentally and theoretically. In this method a potential energy barrier at right-angles to the beam acts as a high-pass energy filter allowing electrons having energies greater than the barrier height to pass through while turning back electrons of lower energy. The potential barrier in the present study was created by applying a negative potential to an electrode consisting of a 600/inch hexagonal copper mesh or an electrode having a pair of single apertures in series (compound aperture). Two different compound apertures, of diameters 0.4 mm and 1.0 mm, were used. The retarding electrode was mounted between two grounded outer electrodes having openings centered on the axis for entrance and exit of electrons. The barrier height was adjusted by means of a small variable bias voltage between the electron gun cathode and the retarding electrode. Auxiliary electron lenses external to the retarding module were used to satisfy the conditions that the beam be normal to the retarding electrode and, for an imaging filter, that an image plane be focused at the retarding electrode. A beam having a narrow distribution of energies was used to calibrate the energy analyzer as a function of bias voltage for the three different configurations of retarding electrode. The calibration curves were then compared with the transmission curve for a beam having a broadened energy distribution. The feasibility of obtaining a filtered image was explored by observing the image of a fine mesh focused into an aperture of the retarding electrode. The experiments were carried out for a beam voltage of 15 kV. At this beam voltage the energy resolution is poor, being 3. 6 volts for the smaller compound aperture, 3. 7 volts for the mesh, and 5.2 volts for the larger compound aperture. Typically, electrostatic analyzers operate on a beam which has been decelerated to low energies before entering the analyzer, in which case the energy resolution is proportionately better. For example, at 150 V the above resolution figures would be 0.036, 0.037, and 0.052, respectively. In view of the potential for high energy-resolution and the attractive features of in-line, rotationally-symmetric systems, it is felt that the retarding-potential analyzer is a promising candidate for further development.

Includes bibliographical references (leaves 174-188). Describes several aspects of cosmic ray composition studies using the Utah Fly's Eye and High Resolution Fly's Eye detectors.

Typescript Includes bibliographical references