Thesis (Ph. D.)--University OF MICHIGAN.

Thesis (M.S.)--University of Michigan, 1976.

Thesis (M.S.)--University of Michigan, 1976.

Thesis (Ph. D.)--University of Missouri--Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 153-159). Also available on the Internet.

Thesis (Ph. D.)--University OF MICHIGAN.

Made available in DSpace on 2014-06-11T19:23:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-09-28Bitstream added on 2014-06-13T20:50:33Z : No. of bitstreams: 1 pinto_jt_me_arafcf.pdf: 1063344 bytes, checksum: 3d55af6aa3dad875adb86aa30580f082 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The vermicomposting of coffee grounds shows great promise for urban areas and university campuses. Several studies have examined using coffee grounds as a substrate for vermicomposting, however, little is known about its effect on plant growth, yield and quality. Therefore, two studies were conducted to assess these effects on greenhouse spinach and field grown bell peppers. Coffee vermicompost (VC) was utilized in a greenhouse spinach study over two spring growing seasons (2011 and 2012). Coffee VC was added to a 1:1:1 (peat, soil, sand) medium by volume (0, 25, 50 and 75%) in 4.5 L clay pots and seeded with `Bloomsdale Longstanding' spinach (Spinacia oleracea). Growth parameters evaluated were fresh leaf weight (FLW), leaf area (LA), spinach plant height, number of leaves, fresh leaf ascorbic acid (AA) and dry leaf nitrate (DLN). In 2011, the highest FLW, LA, number of leaves, AA and nitrate content were seen at the 75% VC application rate. Many parameters were correlated: The FLW and the VC application rate (r=0.41, P<0.0001); the AA content in leaves and the VC application rate (r=0.60, P<0.0001); and the AA and nitrate content in leaves (r=0.45, P=0.011). In 2012, the greatest FLW, height and number of leaves were observed at the 50% VC application rate; the highest nitrate content at 75% VC application rate, with no difference in AA content. A field study was conducted over three seasons (2009–-2011) to compare four treatments (coffee VC, dairy compost, standard fertility (SFT) and no treatment) for their effects on growth, yield, and AA content of bell peppers. Coffee VC and dairy compost were applied to beds at the rate of 22 t/ha and SFT was applied as 212 kg/ha 12:12:12 (N:P:K). Parameters evaluated were total number and weight of marketable and cull (unmarketable) pepper fruits, plant height, leaf chlorophyll index, and fresh fruit AA content. There were no differences detected for pepper fruit yields or AA content, however, plant height and chlorophyll index were greater for the VC and SFT treatments than for the compost and control treatments. These results indicated that coffee VC can improve the yield of greenhouse spinach and that the AA content does not decrease with higher VC application rates, even as nitrate content increases. Results of the bell pepper field study indicated that the coffee VC treatment produces similar growth, yield and AA content as SFT.

Made available in DSpace on 2015-04-01T12:17:40Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3247441 bytes, checksum: c1dfc0c3debca7991c14dcc71ed16144 (MD5) Previous issue date: 2013-11-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The current work aims at investigate the effect of incorporation of a new antioxidant vitamin C(ascorbic acid) in ultrahigh molecular weight polyethylene (UHMWPE) matrix from thermooxidation perspective. Ultrahigh molecular weight polyethylene/vitamin C) blends, with different vitamin C contents (0.5, 1 and 2 wt%) were prepared via compression molding technique, have been investigated using several analytical steps (SEM, DSC, TG, FTIR and antioxidant activity). Thermal degradation behavior of neat UHMWPE and its blends were estimated using the Friedman, the Ozawa, Flynn, and Wall (OFW) methods. Results indicated that the polymer/vitamin C blends have homogeneous morphology. The addition of ascorbic acid seems to have no influence in crystallization and melting properties of the polymer. Moreover, the antioxidant activity of Vitamin C remained in their mixtures with UHMWPE. The analysis of the fracture surface of UHMWPE / vitamin C showed that there was no adhesion between the phases and Spectroscopy results do not show chemical interaction between UHMWPE and vitamin C. In addition, vitamin C was effective to secure the thermal performance of UHMWPE, especially when added at a concentration of 1%wt, it´s increasing the activation energy (Ea) of UHMWPE without changing its profileof reaction order (n). / O presente trabalho teve por objetivo investigar o efeito da incorporação de vitamina C(ácido ascórbico) como um novo antioxidante na matriz de polietileno de ultra alta massa molar (UHMWPE). Foram investigadas misturas de UHMWPE com diferentes teores de vitamina C (0,5;1 e 2%em peso) preparadas por moldagem por compressão. Todas as amostras foram caracterizadas por diferentes técnicas analíticas (MEV, DSC, TG, FTIR e atividade antioxidante). Parâmetros da degradação térmica do UHMWPE puro e incorporado com vitamina C foram determinados pelo método de Friedman, Ozawa, Flynn, e Wall (OFW). Os resultados encontrados apontam para uma distribuição homogênea da vitamina C na matriz polimérica. A sua adição não afetou os processos de cristalização e de fusão da matriz de UHMWPE. Além disso, a atividade antioxidante da vitamina C se manteve nas suas misturas com o UHMWPE. A análise da superfície de fratura do UHMWPE/vitamina C mostrou que não ocorreu adesão entre as fases e a análise de infravermelho indicou a falta de interação química entre estes componentes. Finalmente, a vitamina C foi eficiente para garantir a performance térmica do UHMWPE, principalmente quando foi adicionada em uma concentração de 1% em peso, de modo a aumentar a energia de ativação (Ea) do UHMWPE sem alterar o seu perfil da ordem de reação (n).

Orientador: Célia Maria de Sylos / Banca: João Bosco Faria / Banca: Neura Bragagnolo / Mestre

Existing instrumental techniques must be adaptable to the analysis of novel explosives if science is to keep up with the practices of terrorists and criminals. The focus of this work has been the development of analytical techniques for the analysis of two types of novel explosives: ascorbic acid-based propellants, and improvised mixtures of concentrated hydrogen peroxide/fuel. In recent years, the use of these explosives in improvised explosive devices (IEDs) has increased. It is therefore important to develop methods which permit the identification of the nature of the original explosive from post-blast residues. Ascorbic acid-based propellants are low explosives which employ an ascorbic acid fuel source with a nitrate/perchlorate oxidizer. A method which utilized ion chromatography with indirect photometric detection was optimized for the analysis of intact propellants. Post-burn and post-blast residues if these propellants were analyzed. It was determined that the ascorbic acid fuel and nitrate oxidizer could be detected in intact propellants, as well as in the post-burn and post-blast residues. Degradation products of the nitrate and perchlorate oxidizers were also detected. With a quadrupole time-of-flight mass spectrometer (QToFMS), exact mass measurements are possible. When an HPLC instrument is coupled to a QToFMS, the combination of retention time with accurate mass measurements, mass spectral fragmentation information, and isotopic abundance patterns allows for the unequivocal identification of a target analyte. An optimized HPLC-ESI-QToFMS method was applied to the analysis of ascorbic acid-based propellants. Exact mass measurements were collected for the fuel and oxidizer anions, and their degradation products. Ascorbic acid was detected in the intact samples and half of the propellants subjected to open burning; the intact fuel molecule was not detected in any of the post-blast residue. Two methods were optimized for the analysis of trace levels of hydrogen peroxide: HPLC with fluorescence detection (HPLC-FD), and HPLC with electrochemical detection (HPLC-ED). Both techniques were extremely selective for hydrogen peroxide. Both methods were applied to the analysis of post-blast debris from improvised mixtures of concentrated hydrogen peroxide/fuel; hydrogen peroxide was detected on variety of substrates. Hydrogen peroxide was detected in the post-blast residues of the improvised explosives TATP and HMTD.