This thesis describes a study of the technique and development of a system known as ASIA (Atomiser, Source, Inductively Coupled Plasmas (ICPs) in Atomic fluorescence spectrometry). Copper, nickel and lead boosted-discharge hollow-cathode lamps (BDHCLs), have been compared with the ICP, as excitation sources. A detailed study of the spectra of nickel and lead was performed. No evidence was found for the differences in the radiances between the two sources when the copper lamp was overrun. Although the lamps gave rise to lower blank standard deviation values, the detection limits were worse with the lamp source compared to ICP source. The modified Optica CF4 monochromator originally used, has been replaced by a Bentham Instruments computer controlled monochromator with better light gathering power. The optical arrangement for gathering the fluorescent radiation has also been re-designed. The performance of the modified system has been studied, based on detection limits (DLs), for a number of elements. In general, an improvement of 2 to 3 times in DLs is achieved. Further, improvements in the detection limits for molybdenum and tungsten have been achieved with the development of an on-line preconcentration procedure using a miniature column of Amberlite (IRA-93) anion-exchange resin. A heated spray chamber desolvation system has been evaluated as a sample introduction device for atomiser and source plasmas but, unfortunately the results obtained with the device were unsatisfactory. Problems included periodic instability of the plasmas and salt deposition on the inner walls of the spray chamber when high concentration solutions were aspirated. Also, a brief study of the feasibility of an aerosol modulation device has been performed. Finally, an interference study has been made to investigate the interference effects of high concentrations of interferent elements on a number of analyte elements. Spectral scans were obtained to visualise any possible interference effect. No spectral interference effect was observed on any of the analyte elements due to the interferent elements studied.

M.Ing. / Please refer to full text to view abstract

An experimental search based on previous published theoretical work was made for de Haas-van Alphen-like quantum oscillations in field emission current. The study was motivated by the possible applicability of de Haas-van Alphen measurements to the study of Fermi surfaces near real surfaces, Field emitters were fabricated from bismuth single crystals grown from the melt by a modified Bridgeman technique. Field emission current was measured with the field emitter cooled by contact with a liquid helium bath. Most measurements were made at 4.2° K, although a few measurements were made at 2.02°K; Fowler-Nordheim plots of the experimental current-voltage data were linear over several orders of magnitude. The field emission current was measured as a function of magnetic field strength to twenty kilogauss and as a function of direction, with respect to the emitter axis, for a steady field of ten kilogauss. The results of measurements on four field emitter crystals are reported in this thesis. In most of this work, de Haas-van Alphen-like quantum oscillations were not observed. In one set of data, however, de Haas-van Alphen-like oscillations having a period of 0.50 x 10⁻⁵ G⁻¹ appear to be present. The published theoretical work was reevaluated. As a result of a large effective Dingle temperature for field emitters, and because the effective masses of carriers in bismuth are anisotropic, the de Haas-van Alphen effect in field emission current could be several times smaller than has been suggested in the literature. The sensitivity of the experiments reported in this thesis was not sufficient to allow unambiguous identification of quantum oscillations at the reduced level. An outline of an experimental procedure suitable for observation of the de Haas-van Alphen-like effect in field emission current at the reduced level is provided in the final chapter.

The National Air Emission Monitoring Study (NAEMS) project was funded by the Agricultural Air Research Council (AARC) to evaluate agricultural emissions nationwide. Utah State University (USU) is conducting a parallel study on agricultural emissions at a Cache Valley poultry facility. As part of this parallel study, samples of animal feed, eggs and animal waste were collected weekly from three manure barns (designated: manure barn, barn 4 - manure belt and barn 5 - high rise) from May 2008 to November 2009. These samples were analyzed to determine ammonia content, total Kjeldahl nitrogen content and ammonia emission. The yearly average calculated NH3 values for manure barn, barn 4 and barn 5 were determined in units of mg NH3/gmanure as: 1.1 ± 0.2, 0.6 ± 0.1 and 0.8 ± 0.1, respectively. The yearly average calculated TKN values in units of % N were determined as: 2.0% ± 0.3, 1.6% ± 0.3 and 1.9% ± 0.3 for manure barn, barn 4 and barn 5, respectively. The yearly average of NH3 emission in units of mg NH3/bird-day was determined to be 440 ± 180 mg NH3/bird-day for barn 4, and 540 ± 190 mg NH3/bird-day for barn 5. The ammonia and organic amines emissions in ambient air at a Cache valley confined poultry facility were measured by using a sulfuric acid trapping solution in an impinger train followed ion chromatography (IC) detection. The yearly average concentrations of ammonia in ambient air at the barns were calculated at 11.9 ± 2.9 ppm at the manure belt barn and 12.7 ± 3.1 ppm at the high rise barn. No organic amines were detected in the collected ambient air samples by the ion chromatography method. Because there were no amines detected by the IC method, limits of detection of organic amines in air were studied. The results showed that the organic amines in the manure must occur at a minimum concentration of 1 ppm in order to have sufficient vapor pressure so that enough is transported to the impingers for trapping and subsequently be detected by the IC.

Thesis (Ph. D.)--Oregon Graduate Center, 1980.

M.S. / Applied Physics / The interaction of oxygen with the (310) surface of LaB[subscript 6] has been investigated using Auger electron spectroscopy and mass spectrometric analysis. Measurements were made on both preadsorbed layers of oxygen and in fixed oxygen pressures. Desorption products observed were BO, B2O2, B2O3, and LaO. Oxygen saturation of the surface at room temperature was observed with adsorptions of 50L. Oxides on the surface appear as B2O3 and an unidentified lanthanum bearing oxide. Temperature and pressure dependencies of the desorption products were studied in detail. Faceting [sic Facetting] of the surface into (100) planes was observed.

This research work focused on studying the emission spectroscopy produced from the high energy ion-molecule collision processes in mass spectrometry. The collision experiments are described and divided into 4 chapters (Chapter 3, 4, 5, 6).N2O+● is an ion of atmospheric importance. In chapter 3 the investigation of the collision between high translational energy (4-8 keV range) N2O+● ions and Helium target gas in mass spectrometry using collision induced emission (CIE) spectroscopy is described.In chapter 4, the collision-induced emission (CIE) spectra from 4-8 keV collisions between projectile He+● ions and CO2 target gas (He+●/CO2) were obtained. In Chapter 5, to probe the validity of this hypothesis, CIE experiments were carried out to observe the photon emissions from keV collisions of a selection of projectile ions with O2 target gas. By studying the resulting CIE spectra, a second potential mechanism came to light, one that involves the nearly isoenergetic O2+. A → X state transition. In chapter 6, neutral hydroxymethylene and formaldehyde were generated by charge exchange neutralization of their respective ionic counterparts and then were reionized and detected as recovery signals in neutralization-reionization mass spectrometry in the modified VG-ZAB mass spectrometer.

This research work focused on studying the emission spectroscopy produced from the high energy ion-molecule collision processes in mass spectrometry. The collision experiments are described and divided into 4 chapters (Chapter 3, 4, 5, 6).N2O+● is an ion of atmospheric importance. In chapter 3 the investigation of the collision between high translational energy (4-8 keV range) N2O+● ions and Helium target gas in mass spectrometry using collision induced emission (CIE) spectroscopy is described.In chapter 4, the collision-induced emission (CIE) spectra from 4-8 keV collisions between projectile He+● ions and CO2 target gas (He+●/CO2) were obtained. In Chapter 5, to probe the validity of this hypothesis, CIE experiments were carried out to observe the photon emissions from keV collisions of a selection of projectile ions with O2 target gas. By studying the resulting CIE spectra, a second potential mechanism came to light, one that involves the nearly isoenergetic O2+. A → X state transition. In chapter 6, neutral hydroxymethylene and formaldehyde were generated by charge exchange neutralization of their respective ionic counterparts and then were reionized and detected as recovery signals in neutralization-reionization mass spectrometry in the modified VG-ZAB mass spectrometer.

Acoustic emission(AE) is one of the most sensitive techniques to non invasively monitor deformation, fatigue, and fracture of many materials. The purpose of this study was to evaluate the potential to use AE to detect local failure events within porous ceramic materials. The primary material of interest was mineralized trabecular bone. A better understanding of the failure of trabecular bone is highly relevant to skeletal fragility diseases such as osteoporosis. This study sought to develop a post processing technique that could strengthen the relation between the events detected and the phenomena occurring as a specimen is loaded. The deficiency in other techniques is that they did not fully make a quantitative correlation between acoustic emission event characteristics and the physical occurrence of damage events. The study evaluated the use of seismic power laws because these laws were able to attach a quantitative model to an earthquake and its successive aftershocks. Earthquake transmission has similar propagation attributes when compared to acoustic emission; seismic waves radiate from the epicenter of an earthquake. Acoustic waves radiate from the source of energy release in an acoustic emission event. The study measured the acoustic emission response of trabecular bone and highly oriented ceramics. The bone and ceramics were extracted in two perpendicular directions so that the structural orientation was different. The study sought to evaluate if the power-laws could differentiate the acoustic emission response based on varying the material and varying the structural orientation. The samples were quasi-statically compressed; the mechanical and acoustic emission data were simultaneously recorded. The study found that using the seismic power-law did not statistically differentiate the directional orientation for trabecular bone or ceramic specimens. Acoustic emission did indicate that event detection was different for each type of the of material. Correlations were established with the acoustic emission response and the mechanical testing data. These relationships were explainable because of the mechanical properties of the material.

The delayed neutron emission rates of U-235 and Pu-239 samples were measured accurately from a thermal fission reaction. A Monte Carlo calculation using the Geant4 code was used to demonstrate the neutron energy independence of the detector used in the counting station. A set of highly purified actinide samples (U-235 and Pu-239) was irradiated in these experiments by using the Texas A&M University Nuclear Science Center Reactor. A fast pneumatic transfer system, an integrated computer control system, and a graphite-moderated counting system were constructed to perform all these experiments. The calculated values for the five-group U-235 delayed neutron parameters and the six-group Pu-239 delayed neutron parameters were compared with the values recommended by Keepin et al. (1957) and Waldo et al. (1981). These new values differ slightly from literature values. The graphite-moderated counting station and the computerized pneumatic system are now operational for further delayed neutron measurement.