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A direct method for source determination of atmospheric formic and acetic acid, through carbon isotopic analysis of the ambient acids and their potential sources, has been successfully developed and tested. These first carbon isotopic measurements of formic acid in the atmosphere were found to be fairly constant, regardless of location. This is consistent with a single dominating source of formic acid, with vegetation emissions being the most likely controlling source. Collection of relatively large quantities (0.3$-$3.0 mg) of the organic acids, which was necessary for carbon isotopic measurements, was effectively accomplished by a new method using calcium hydroxide-treated filters with a high-volume sampler. Samples were collected on a regular basis at Mount Lemmon, Arizona (elevation = 9200 feet A.S.L.). Atmospheric concentrations showed a well-defined seasonal pattern, with the lowest concentrations (about 0.2 ppbv) occurring in the middle of the winter, which steadily increased to a maximum of nearly 2 ppbv in the summer. The ¹³C content (δ ¹³C) of HCOOH averaged -20.9 ± 2.5 ‰ during the growing season (April-September) and -23.2 ± 3.5 ‰ during the non-growing season at Mount Lemmon. Isotopic measurements of formic acid from several other locations included two west coast marine sites (δ ¹³C range of -19.1 to -24.6 ‰), three Colorado Rocky Mountain samples averaging -23.2 ± 1.0 ‰, two from the prairie of North Dakota (-23.5 ± 1.0 ‰) and three samples collected in the urban Tucson, Arizona area (-20.8 ± 3.4 ‰). Source measurements included HCOOH emissions from two species of formicine ants (-18.8 ± 1.7 ‰), and HCOOH in automobile exhaust (-28 ‰ from leaded gasoline, and -48.6 ‰ from unleaded). Further support for a biogenic source of atmospheric HCOOH came from the carbon-14 analysis of six Mount Lemmon HCOOH samples (93-113% modern carbon), using accelerator mass spectrometry. Carbon isotopic fractionation during exchange of HCOOH between the liquid and gas phases was investigated through a gas/liquid partitioning experiment. A first experimental measurement of the Henry's Law coefficient (Kᴴ) averaged 7400 ± 800 M/atm. Fractionation between HCOOH(g) and HCOOH(aq) was found to be negligible.

The overall goal of this research is to characterize the potential-dependent structure and composition of the alcohol-Ag electrochemical interface. The approach involves the use of a variety of electrochemical and spectroscopic tools to arrive at a consistent model for a series of straight-chain alcohols (methanol, ethanol, 1-propanol, and 1-pentanol) at Ag electrodes. There are essentially four areas of investigation presented in this dissertation. The first portion of this work has been directed at the development of charge coupled device detection in Raman spectroscopy so that many of the interface investigations could be performed. The advantages and limitations of these detectors in Raman spectroscopy are addressed. The second area involves the characterization of in-situ alcohol-Ag electrochemical interfaces using Raman spectroscopy and associated surface selection rules for the evaluation of solvent orientation and bonding. Since the series of alcohols offers a systematic variation in solvent properties, these studies provide substantial insight regarding some of the chemical interactions which can dictate orientation. The development of emersed electrode technologies is also presented as a means to improve selectivity for surface molecular species over bulk molecular species. The utility of this approach is demonstrated for a variety of straight-chain alcohols at both rough and smooth Ag electrodes. Conditions for emersing the molecular interface, intact, under potential control are presented. Finally, double layer capacitance measurements are performed to offer additional insight regarding alcohol solvent structure and interfacial composition as a function of electrode potential. In addition, capacitance-potential plots are used along with the Hurwitz-Parsons analysis to determine absolute surface coverage of Br⁻ as a function of electrode potential. These results are correlated with the Raman spectroscopic results to obtain a consistent model for the structure and composition of the alcohol-Ag electrochemical interface.

The application of mass spectrometry to verification of the structure of 3-methyluridine (m³U) isolated by HPLC from normal human urine is described. m³U has been used as an internal standard for studies of urinary nucleosides, a practice that is discouraged with the confirmation of m³U as a naturally occurring compound. Mass spectrometry has been used for the identification of 5'-deoxyxanthosine (5'-dX) a novel nucleoside in normal human urine. Initial concern over availability of a reference sample of 5'-dX prompted investigations of the structure/fragmentation relationships of the TMS deratives of 2'-, 3'-, and 5'-deoxynucleosides toward differentiation between the three deoxynucleosides. Results are presented which allow discrimination between the model compounds, deoxyanalogs of adenosine. Subsequent to the deoxynucleoside fragmentation studies, a biosynthetically produced reference sample of 5'-dX became available for direct comparison of mass spectra and chromatographic retention times which, when combined with observations from the deoxynucleoside studies established the structure of 5'-dX. In response to the large number of mass spectra produced from the GC-MS analysis of a TMS derivatized urine sample, computer software has been written to aid in spectral analysis. Examples are shown in which the software uses established fragmentation rules to assign structure to ions in the mass spectrum and suggest modifications in the sugar portion of two urinary nucleosides. The structure/fragmentation relationships of the unique antitumor drug taxol has been studied by EI, CI and FAB mass spectrometry. Information is presented showing characteristic fragmentation of the side-chain and verification of functional groups attached to the taxane ring. Studies have been conducted to determine the relationship between target temperature and matrix and sample lifetime in the source of the mass spectrometer. Results are presented showing that cooling the target permits the use of matrix materials that are too volatile at ambient temperatures thus extending the range of compounds that can be studied by mass spectrometry. A recently constructed four-sector mass spectrometer is described with a detailed discussion of instrumental capabilities. Results of experiments designed to apply these capabilities to the structural analysis of TMS nucleosides using FAB ionization are discussed with an emphasis on the fragmentation unique to 4-sector daughter ion experiments compared with conventional studies and 2-sector daughter ion results.

A unique echelle spectrometer system employing charge injection device (CID) array detectors for use in inductively coupled plasma atomic emission spectroscopy (ICP-AES) is described. The echelle spectrometer described offers numerous advantages over previous systems including improved light throughput and extended wavelength coverage including the vacuum-ultraviolet (VUV) down to 165 nm. Several improvements in CID array detector technology are also described. Low exposure level linearity is improved and full well capacity is increased by fabricating the CIDs with <100> silicon as opposed to <111> silicon. Low sensitivity in the far-ultraviolet (far-UV) has been considered a major disadvantage when using silicon based detectors due to absorbance in the overlying gate structure of the devices. The problem has been circumvented by utilizing a wavelength conversion phosphor to improve the effective sensitivity in the far-UV. The read noise of the CID has been reduced by a factor of 3 by utilizing a preamplifier on every row of the device. Utilization of this system for ICP-AES yields numerous advantages over conventional photomultiplier tube (PMT) based systems. Elemental detection limits comparable to or better than those obtained on PMT based instrumentation are achieved in the UV and visible regions. Sensitivities at wavelength less than 200 nm are degraded by a factor of 5 relative to PMT based systems due to decreased echelle grating efficiency in that wavelength region. In most cases, the advantages of continuous wavelength coverage provided by CID array detectors outweighs any loss in sensitivity. Operating parameters including precision, resolution and background correction are also discussed. Analysis of both the National Institute of Standards and Technology (NIST) Standard Reference Materials (SRM) 1643b and 1646 demonstrates that the system is capable of the simultaneous determination of a large number of elements at a large number of wavelengths with a high degree of accuracy even in spectrally complex matrices.

A molecular hydrogen laser, with an output of 7.8 eV photons in the vacuum ultraviolet, is evaluated as a selective source for photoionization mass spectrometry. Types of compounds ionized by the laser include a variety of amines, nitrogen heterocycles, drugs of abuse, pharmaceuticals, and polynuclear aromatic hydrocarbons (PAHS). The laser is coupled to a time-of-flight mass analyzer, which allows a spectrum to be recorded with each laser pulse. The laser is a "soft" ionization source and mass spectra of nearly all of the compounds studied yield single ion peaks due to the parent molecule with no fragments. This results in simplified mass spectra with a one-to-one correspondence of photoactive molecules with molecular ion peaks. Since the photoionization threshold of the laser is relatively low, selectivity of the photoactive species is high in the presence of a complex sample matrix. The performance of the laser source is improved with a few changes in the original design. In addition, the previous method of recording mass spectra with a photographic emulsion is replaced with a digital oscilloscope, which averages spectra over many laser pulses. As a result, a true assessment of the technique's sensitivity is finally achieved. The time-of-flight mass spectrometer is modified with a new microchannel plate ion detector and preamplifier. As a result, detection limits for PAH's improve by nearly three orders of magnitude, from the 100 ng range to the 100 pg range. Selectivity of the laser photoionization source in complex mixture analysis is demonstrated with the ability to detect PAH's in a drinking water sample at concentrations below 100 parts-per-trillion, using a simple solid-phase extraction technique. Application of the technique for rapid screening of drugs of abuse in urine is demonstrated where solid-phase extraction columns are utilized for sample pretreatment. Urine samples spiked with drugs such as cocaine, codeine, morphine, phencyclidine, and methadone, yield photoionization mass spectra consisting of parent molecular ions for the drugs with a few noninterfering ion signals from the matrix. The technique is evaluated and compared to other drug screening techniques such as enzyme-multiplied immunoassay.

The overall goal of this research is to characterize the solvent and electrolyte structure of the nonaqueous electrochemical double layer in the isomers of butanol on Ag and Au electrodes. Electrochemical and spectroscopic methods are employed to obtain structural information about the interface. In order to gain a better understanding of the Raman vibrational assignments of these alcohols, the Raman vibrational assignments were determined for a series of n-alcohols (n = 3-6, 8, 12, 14, and 18) in the spectral region from 700 to 1320 cm⁻¹ and 2800 to 3000 cm⁻¹. Solvent structure of the butanol isomers, 1-butanol, 2-butanol, and iso-butanol, were determined in-situ on rough Ag and Au electrodes using surface enhanced Raman scattering. Surface Raman selection rules were used to determine the average molecular orientation of these solvents at the electrode under potential control. The electrolyte structure in the nonaqueous electrochemical double layer has been determined using surface enhanced Raman scattering and differential capacitance measurements. Surface enhanced Raman scattering studies of the electrolyte structure were focused on probing the molecules solvating the cation and anion species, namely the alcohol and water impurity species. The ν(O-H) bands from these solvation species were monitored in these nonaqueous systems under potential control. These ν(O-H) bands distinctly describe the behavior of the LiClO₄, LiCl, LiBr, and LiI at the electrode under potential control. Differential capacitance measurements using an AC impedance method were performed to quantify anion coverages at smooth Ag electrodes in the butanol isomers. Cl⁻ and Br⁻ coverages were determined in the butanol isomers. This technique, coupled with SERS, provides complementary information about the electrolyte structure at the nonaqueous electrochemical double layer. The solvent and electrolyte structure is also determined ex-situ on emersed rough and smooth Ag and Au electrodes using Raman spectroscopy. Upon emersion of the electrodes into an inert Ar environment, solvent orientation and electrolyte behavior are investigated using Raman spectroscopy. These studies demonstrate both the utility of using Raman spectroscopy to probe emersed electrodes and the validity of emersing the electrode while preserving the double layer structure.

La matriz FODA es la herramienta de análisis por excelencia para fines de negocios, y se enseña en cursos de pregrado y postgrado. Sin embargo, se entiende que la elección de los factores críticos de éxito (FCEs) que se incluyen en la matriz para el análisis es un proceso muy subjetivo y no estructurado, que da cabida a sesgos y arbitrariedad. Una forma de dar una mejor base y respaldo a los resultados del análisis es mediante la utilización del Proceso Jerárquico Analítico (AHP) con el fin de ponderar la importancia de los FCEs en la matriz FODA y aumentar la fiabilidad de los resultados. Este documento contiene el diseño de una estrategia para enseñar este tema en un curso de planificación de marketing, con la adición de una técnica útil para superar las limitaciones de la herramienta. / The SWOT matrix is the quintessential analysis tool for business purposes, and is taught both in undergraduate and postgraduate courses. However, it is widely understood that the selection of the critical success factors (CSFs) that are included for analysis in the matrix is a very subjective and unstructured process, leaving room for bias and arbitrariness. One way to give a better foundation and support to the analysis results is by utilizing Analytic Hierarchical Process (AHP) in order to weigh the importance of CSFs in the SWOT matrix and increase reliability of the output. This paper contains the design of a strategy to teach this topic in a marketing planning course, with the addition of a useful technique to overcome the limitations of the tool.

Call number: LD2668 .T4 1957 S57 / Master of Science

We look at the algebraic properties of Gevrey, analytic and ultraanalytic function spaces, namely their closure under composition, division and inversion. We show that both Gevrey and ultra-analytic spaces, G s with 1 ≤ s &lt; ∞ and 0 &lt; s &lt; 1 respectively, form algebras. Closure under composition, division and inversion is shown to hold for the Gevrey case. For the ultra-analytic case we show it is not closed under composition. We also show that if a function is in G s , with 0 &lt; s &lt; 1 on a compact set, then it is in G s everywhere.