6 research outputs found

    Development and Applications of High Resolution Kinetic Atmospheric Pressure Ionization Mass Spectrometry in Atmospheric Chemistry

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    Much important work has been done to understand reaction pathways and identify products, yields, and reaction rates for atmospheric oxidation processes. Non-methane hydrocarbons (NMHCs) are the most significant of the organic compounds present in the atmosphere from a chemical perspective and are released into the atmosphere from both natural and anthropogenic sources. The oxidation of these hydrocarbons by hydroxyl radical HO generates products that may themselves be toxic, that play a major role in the formation of photochemical smog, and that to a lesser extent contribute to the formation of acid precipitation. NMHCs have chemical reactivities many times that of methane, the most abundant HC in the atmosphere. However, the atmospheric oxidation processes of less than 50% of atmospheric NMHCs are known. A new experimental technique is needed that can provide insight into atmospheric oxidation products, reaction intermediates, and the relative importance of secondary reaction pathways that follow the initial attack of HO upon a hydrocarbon. The technique should operate at atmospheric pressure to better represent natural reaction processes and conditions, and provide a rapid and direct measure of product identities and yields. In this study we will describe the development and application of a technique that we believe meets these requirements, a technique we call High Resolution Kinetic Atmospheric Pressure Ionization Mass Spectrometry (HRKAPIMS). We begin with the use of atmospheric pressure ionization mass spectrometry in studies of atmospheric oxidation processes. We first describe a potential pitfall in the use of APIMS for the analysis of smog chamber experiments, a common APIMS application, discussing methods to eliminate interference reactions that would otherwise make interpretation difficult. A new experimental approach to the use of APIMS for the analysis of oxidation processes is next described and its use demonstrated. The oxidation of toluene by API source-generated HO produces oxidation products that are protonated and detected by the mass spectrometer. With this approach, we observe all the products found in a variety of previous studies employing a large array of experimental setups and analytical instrumentation. This is significant because our experiments are carried out in a far simpler experimental environment. Toluene is chosen for these experiments because it is an important constituent in polluted urban atmospheres with a complex oxidation mechanism that remains poorly understood. We describe the development of HRKAPIMS, a powerful new approach that allows the simultaneous detection of stable products along with free radical intermediates. The use of nitric oxide to affect product yields is demonstrated, giving valuable insights into reaction kinetics and mechanisms. We also address the theoretical aspects of HRKAPIMS, describing semiempirical calculations to estimate gas-phase basicities for a wide variety of compounds and discuss the errors implicit in this approach. The use of gas-phase basicities is discussed in terms of mass spectrometric analysis and analyte response. Kinetic and thermodynamic modeling is used to address the issues of APIMS and HRKAPIMS sensitivity and response and gain insights into the conditions necessary for linear response and quantitative detection of analytes

    Vale Oliver MacDonagh

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    Contos de Camp Wilde: tornando queer a pesquisa em educação ambiental Tales from Camp Wilde: queer(y)ing environmental education research

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    Este artigo questiona o relativo silêncio da teoria e da teorização queer sobre a pesquisa em educação ambiental. Exploramos algumas possibilidades para tornar queer a pesquisa em educação ambiental ao criar (estimulando outras/os a fazer o mesmo) narrativas de Camp Wilde, um local imaginário que nos ajuda a expor o fato de este ser um campo marcado por uma construção heteronormativa. Essas narrativas propõem métodos alternativos de representação e (re)produção do sujeito e do objeto de nossas indagações e nossas identidades como pesquisadoras/es. As/os colaboradoras/es utilizam-se de diferentes recursos teóricos como história da arte, desconstrução, ecofeminismo, crítica literária, estudos culturais populares e pós-estruturalismo feminista a fim de desenvolver uma nova orientação para a pesquisa em Educação Ambiental, a qual esperamos que jamais seja categorizada como um 'novo gênero'.<br>This paper questions the relative silence of queer theory and theorizing in environmental education research. We explore some possibilities for queering environmental education research by fabricating (and inviting colleagues to fabricate) stories of Camp Wilde, a fictional location that helps usto expose the facticity of the field's heteronormative constructedness. These stories suggest alternative ways of (re)presenting and (re)producing both the subjects/objects of our inquiries and our identities as researchers. The contributors draw on a variety of theoretical resources from art history, deconstruction, ecofeminism, literary criticism, popular cultural studies, and feminist poststructuralism to perform an orientation to environmental education research that we hope will never be arrested by its categorization as a "new genre.
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