Chemical detection, including analysis of gases and liquids, is a large field in environmental research and industry. It requires sensitive, rapid, and inexpensive chemical sensors. Many industrial materials such as coatings and adhesives readily absorb chemical analytes, which may result in changes of their chemical, mechanical, and optical properties. This uptake of volatile organic compounds either from the gas phase or from an aqueous solution into a thin film is frequently accompanied by a change in material refractive index and film thickness. While the undesired swelling of thin film coatings and their refractive index changes affect their use in harsh environments, the sensitivity of some polymers to solvent vapours can also be exploited for sensing applications. In this project, a method is reported for real-time monitoring of vapour uptake by simultaneous detection of the refractive index, n, and thickness, d, of thin transparent films with a precision of 10-4 for refractive index and 100 nm for thickness. The setup combines a total internal reflection refractometer with an interferometric imaging method. Two setups using 1550 nm and 635 nm measurement wavelengths were developed, with a detection rate of 1 second per measurement. Two processing methods using a fast Fourier transform algorithm to calculate n and d are applied to the experimental results and compared. Both methods could extract n and d simultaneously from each image captured by the refractometer. The results show that the setup is capable of monitoring film RI and thickness change in real-time. The partitioning of volatile organic compound vapours into polydimethylsiloxane (PDMS) and PDMS-polydiphenylsiloxane (PDPS) copolymers is described. The system is also suited for characterization of other solid and liquid films like SU-8 photoresist and crude oil. It shows great potential in commercial applications of thin film characterization. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2013-09-19 22:21:38.836

Volatile organic compounds (VOCs) are organic chemicals typically characterized as having low molecular weight, low solubility in water, and high vapor pressure. Consequently, they readily evaporate from liquid to the gaseous phase at standard temperature and pressure. VOCs are produced by many microorganisms as a result of both uninduced and induced metabolic pathways. Volatile-based microbial inhibition in environments such as soil is well founded, with numerous antimicrobial VOCs and formulations having been identified. Inhibitory VOCs are of particular interest as microbial control agents, as low concentrations of gaseous VOCs have been observed to elicit significant antimicrobial effects. It is believed that this contact-independent antagonism may present unique advantages over traditional microbial control methods, particularly where contact-dependent treatment methods are either impractical or inconvenient. This method may be of particular benefit for managing infections where disease may become pervasive in the population, such as with white-nose syndrome (WNS) among bats. A list of potential antifungal compounds and formulations was compiled by referencing the scientific literature. Screening of compounds and formulations was conducted through toxicity analyses and antimicrobial susceptibility testing for the in vitro ability of VOCs and formulations to inhibit growth of select pathogenic fungi. A dispersal system was developed that entailed electrical circuit and software engineering as well as quantitative analysis to validate consistent and accurate dispersal of potential treatment compounds and formulations. Successful completion of these goals culminated in exposure trials involving live bats to determine any significant toxicological effects. Ex and in situ treatment trials were conducted to determine efficacy of promoting the reduction of disease severity and increasing survivorship of infected bat populations. The identification of volatile-based inhibitory compounds, in conjunction with a novel method for accurate and automated delivery, could prove a promising treatment and prophylactic in combatting microbial pathogenesis and contamination.

O primeiro capítulo desta dissertação é dedicado a uma revisão teórica da interação dos raios-X com cristais e métodos utilizados para a determinação de estruturas cristalinas. Nos capítulos seguintes, descreve-se os equipamentos experimentais utilizados e resolução de duas estruturas cristalinas cujos principais resultados são apresentados a seguir: Estrutura do complexo HO(ReO4)34 TDTD 3 H2O. Sistema cristalino; monoclínico; grupo espacial P21/c; a=17.955(3) Å b=17.100(6) Å c=12.570(3) Å &#946=92.48(2) ° V=3855(3) ޵ z=4; Dc = 2.720 g/cm3; (MoK&#945)= 0.71073 Å &#181=114.08 cm-1. O índice de discordância final foi de R = 6.4% para 3050 reflexões com I >3&#963(I). O cátion HO+3 é coordenado por oito átomos de oxigênio, que configuram um dodecaedro (simetrias D2d). Os poliedros de coordenação são ligados por grupos TDTD, dando origem a cadeias infinitas na direção a. Estrutura de Ormosalin - C14H16O6. Sistema cristalino: monoclínico, grupo espacial: P21/c; a=10.765(4) Å b=14.692(5) Å c=8.374(4); &#946=98.02(3)° V=1305(2) &#1973, z=4, Dc = 1.43 g/cm3, &#955(MoK&#945)=0.71073 &#197, &#191=0.07 mm-1; R=0.058 para 807 reflexões com estrutura conta com dois anéis de cinco membros em conformação torcida antissimétrica / In the first chapter of this work we review some theoretical aspects concerning the interaction of X-rays with crystals and the methods used to determine crystal structure. The following chapters describe the experimental equipments used and the determination of two crystalline structures. The main results obtained are now out11ned. The structure of the complex HO(ReO4)34 TDTD 3 H2O. Crystal system, monoclinic, space P21/c; a=17.955(3) Å b=17.100(6) Å c=12.570(3) Å &#946=92.48(2) ° V=3855(3) ޵ z=4; Dc = 2.720 g/cm3; (MoK&#945)= 0.71073 Å &#181=114.08 cm-1. The final R factor was 6.4 % for 3050 ref1eetions with I&#88053&#963(I). The cation HO+3 is coordinated by eight oxygen atoms which have a dodecahedron configuration (symme - try D2d). The coordination polyhedrons are linked together by a TDTD group that coordinates two neighbouring cations HO+3, giving rise to an infinite chain along the crystallographic a direction. The structure of Orrnosalin C14H16O6. Crystal system, monoclinic; space group P21/c; a=10.765(4) Å b=14.692(5) Å c=8.374(4); &#946=98.02(3)° V=1305(2) &#1973, z=4, Dc = 1.43 g/cm3, &#955(MoK&#945)=0.71073 &#197, &#191=0.07 mm-1; R=0.058 for 807 reflections with I&#88053&#963(I). The structure consists of two five membered rings forming a anti - symmetric twisted conformation

O presente trabalho teve por objetivo verificar a possibilidade de obtenção de filmes finos pela polimerização por plasma de éter etílico, acetato de metila e de etila, e testes dos referidos filmes quanto à possibilidade de adsorção de compostos orgânicos polares, pois filmes adsorventes podem ser usados na construção de sensores e pré-concentradores. Utilizou-se para a polimerização por plasma os reagentes puros, mistura de éter etílico com oxigênio ou acetona ou os acetatos de metila e etila. Em todos os casos obtiveram-se filmes sobre substrato de silício e estes filmes apresentaram pouco ou nenhum descolamento por cerca de um ano. Os filmes foram caracterizados por perfilometria, para determinar a taxa de deposição, por espectroscopia de infravermelho, para avaliar as espécies polares e medida de ângulo de contato com uma gota de 4 µL de água destilada e soluções aquosas de 2-propanol ou acetona, para comprovar o caráter hidrofílico e organofílico, respectivamente. Os filmes a base de éter etílico apresentaram taxas de deposição entre 80 e 300 Å/min, além de alta intensidade relativa da banda de OH, medida por espectroscopia de infravermelho. Os ângulos de contato ficaram próximos a 75°, mostrando uma superfície hidrofílica. Adição de oxigênio ao plasma favoreceu a oxidação da molécula, conseqüente formação de CO e aumento da medida de ângulo de contato. Acetona, por sua vez, além de favorecer a produção de CO aumenta a formação de particulados e a medida de ângulo de contato. Deposição em câmara fechada favorece o aumento da taxa de deposição e formação de OH, além de pequena diminuição da medida de ângulo de contato. Adições dos acetatos de metila e/ou etila torna o sistema complexo e de difícil controle. Para os ésteres obteve-se janela de processo estreita, onde para acetato de metila observaram-se taxas de deposição maiores e medidas de ângulo de contato menores, entre 160 e 510 Å/min, e 54° a 68°, respectivamente, o que prova que a superfície é hidrofílica. A espectroscopia de infravermelho mostrou bandas semelhantes às bandas encontradas para éter etílico. Deposição em câmara fechada aumentou a taxa de deposição e favoreceu a diminuição das medidas de ângulo de contato. No plasma de acetato de etila observaram-se taxas de deposição alta e ângulos de contato intermediários entre filmes a base de éter etílico e acetato de metila, entre 350 e 1200 Å/min, e 61° a 72°, respectivamente. A superfície é hidrofílica e a espectrocopia de infravermelho mostrou bandas semelhantes às bandas encontradas para éter etílico, porém a banda CO apresenta alta intensidade relativa. A deposição em câmara fechada aumentou a taxa de deposição e a intensidade relativa de CO, obtendo-se ângulos de contato menores se comparados aos da deposição em fluxo contínuo.A medida de ângulo de contato para soluções aquosas de 2-propanol e acetona mostrou que os filmes são organofílicos e que apresentam maior afinidade por 2-propanol. A deposição sobre estrutura padrão em alumínio mostrou boa conformidade de degrau para todos os filmes. Medidas em microbalança de quartzo mostraram que os filmes adsorvem compostos orgânicos polares. Deposição dos filmes de éter e ésteres sobre filme a base de hexametildissilazana mostrou a formação de um filme contínuo, mas que rapidamente apresenta estresse, apesar de não ocorrer descolamento. A deposição sobre placas planas de acrílico mostrou um filme aderente tanto para éter etílico quanto para os ésteres. Estes filmes se apresentam hidrofílicos e organofílicos. Microcanais usinados em acrílico demonstraram a possibilidade do uso do filme na produção de estruturas pré-concentradoras. / The aim of this work is to characterize thin films obtained by plasma polymerization of ethyl ether, ethyl or methyl acetate. The films were tested for adsorption of polar organic compounds in order to evaluate their use for sensors or preconcentrators manufacturing. It was tried plasma polymerization of pure reactants and mixtures of ethyl ether with oxygen, acetone, methyl or ethyl acetate. For all reactants and mixtures films were obtained on silicon and peeling did not occur during one year of observation. Measurements of profilemeter, infrared spectroscopy, contact angle for drop of water, 2-propanol and acetone aqueous solutions were used to determine deposition rate, polar species and hydrophilic or organophilic character, respectively. For ethyl ether the films show a deposition rate between 80 and 300 Å/min and high OH relative intensity. Water contact angles were approximately 75º for all films, therefore the surfaces are hydrophilic. Oxygen addition to the plasma favors ethyl ether oxidation, increase in CO relative intensity and water contact angle. Acetone addition favors rise not only in CO relative intensity and water contact angle but also in particle formation. Deposition on closed chamber mode favors the increase of deposition rate and OH formation but the diminish on water contact angle. Mixture with methyl or ethyl acetate turns the system complex and difficult to control. The acetates process window acetates were narrow but presented higher deposition rates, from 160 A/min to 510 A/min, and lower water contact angles, from 54 º to 68º. Infrared spectroscopy shows the same species found for ethyl ether deposition. Deposition on closed chamber mode increases deposition rate and decreases the water contact angle. Ethyl acetate plasmas show high deposition rate but low water contact angle values when compared to methyl acetate. The deposition rates and water contact angles lie between 350 and 1200 A/min and 61º and 72º, respectively. Infrared spectroscopy shows the same species found on ethyl ether deposition but co presents high relative intensity. Deposition on closed chamber mode not only rises the deposition rate and CO relative intensity but also lowers the water contact angle. Contact angle measurements for 2-propanol and acetone aqueous solution show the surface is organophilic and show bigger affinity for 2-propanol aqueous solution. Deposition on aluminum lines deposited on silicon shows conformal deposition for all films. Quartz crystal measurements show the films adsorb polar organic compounds. Plasma deposited ethyl ether, methyl or ethyl acetate films on plasma deposited hexametyldisilazane substrates showed a continuous film that easily stress, although peeling was not observed. Deposition on poly(methyl methacrylate) showed good adhesion for all films. These films are also hydrophilic and organophilic. Micromachinned microchannels showed the possibility of adsorption and preconcentrators development.

Made available in DSpace on 2014-06-11T19:31:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-28Bitstream added on 2014-06-13T20:41:07Z : No. of bitstreams: 1 cardozo_mtd_dr_jabo.pdf: 446876 bytes, checksum: 0b413178ee7b84a67f1f7a95da08f058 (MD5) / Na produção de hortaliças é fator determinante a adubação aplicada nas dosagens corretas e a reposição de água no solo em quantidades ideais. A adubação com compostos orgânicos pode diminuir o custo da produção e proporcionar aumento da produtividade. O presente trabalho teve como objetivos determinar os efeitos das reposições de água de irrigação na produtividade, e a dosagem do composto de lixo a ser utilizada na cultura do pimentão quando cultivada em ambiente protegido. O experimento foi conduzido em estufa modelo arco com 280 m2. O delineamento experimental foi em blocos casualizados com 24 tratamentos em esquema fatorial de 6 x 4 (formas de adubação e reposição de água no solo, respectivamente). Quanto à adubação, foram seis formas: adubação mineral e adubação com composto de lixo orgânico (4 t ha-1, 8 t ha-1, 12 t ha-1 e 16 t ha-1), mais uma testemunha sem adição de adubos. Quanto às reposições de água no solo foram de 70%, 100%, 130% e 160% da lâmina necessária para elevar o solo à capacidade de campo. Foram determinados o número de frutos, altura das plantas, diâmetro do caule, eficiência do uso da água e a produtividade da cultura. Dentre os resultados, verificou-se que quando a reposição de água no solo foi efetuada integralmente (100% de reposição) a produtividade foi similar entre as adubações com composto de lixo orgânico de 16 t ha-1, 12 t ha-1 e 8 t ha-1 / In vegetables production, the correct dosages of applied fertilizer and replacement of water in the soil in optimal amounts is a determining factor. The fertilization with organic compounds can decrease the production cost and provide increased productivity. This study aimed to: determine the effects of different replacement of irrigation water in crop yield, and optimal dosage of organic compound to be used in sweet pepper when grown in a greenhouse. The experiment was conducted in a bow model greenhouse with 280 m2. The experiment was designed in randomized blocks with 24 treatments in a factorial arrangement of 6 x 4 (types of fertilization and water replacement in the soil, respectively). As for fertilization, it’s used six forms: fertilization with mineral fertilizer and organic compound (4 t ha-1, 8 t ha-1, 12 t ha-1 and 16 t ha-1) and one as control, without addition of fertilizers. For the water replacement in the soil, it’s used 70%, 100%, 130% and 160% of the blade to raise the soil at field capacity. It was determined the number of fruits, plants height, stalk diameter, efficiency of water use and crop productivity. Among the results, it was found that when the replacement of water in the soil was made in full (100% replacement) the productivity was similar between the fertilizer with organic waste compound of 16 t ha-1, 12 t ha-1 and 8 t ha-1

No description available.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Nesta pesquisa, objetivou-se avaliar o processo de compostagem utilizando-se matÃria orgÃnica disponÃvel no banco de mudas da cidade de Sobral - CE, (esterco eqÃino e palhas de carnaÃba) em trÃs sistemas de aeraÃÃo: com injeÃÃo de ar, sucÃÃo de ar e injeÃÃo e sucÃÃo ar em ciclo (hÃbrido), observando-se os parÃmetros recomendados pela legislaÃÃo brasileira vigente, durante as fases de degradaÃÃo ativa e de maturaÃÃo. O experimento foi instalado com trÃs tratamentos, sendo um (01) sob o modo positivo; um (01) sob o modo negativo e um (01) sob o modo hÃbrido, obedecendo as proporÃÃes de 30% de esterco eqÃino e 70% de palhas, para todos os tratamentos. Cada tratamento foi repetido 3 (trÃs) vezes, perfazendo, assim, um total de 9 (nove) parcelas. Foi realizada a avaliaÃÃo destes processos, tendo sido observadas, principalmente, a influÃncia da aeraÃÃo e da umidade no desempenho destas tÃcnicas de tratamento, em leiras estÃticas aeradas. Durante a fase ativa, as leiras sob o modo positivo apresentaram reduÃÃo mÃdia de matÃria orgÃnica de 26,55%, as leiras sob o modo negativo de 21,78%, enquanto que as leiras, sob o modo hÃbrido de 31,21%. Durante a fase de maturaÃÃo, foram reviradas trÃs leiras de cada sistema de aeraÃÃo. A reduÃÃo mÃdia da matÃria orgÃnica das mesmas foi de 50,63%, em 50 dias; as demais apresentaram reduÃÃo mÃdia de 39,54%, em 60 dias. Durante a fase ativa, as leiras operadas sob o modo positivo apresentaram, em mÃdia, reduÃÃo de Carbono de 26,55%, no perÃodo de 40 dias; as leiras sob o modo negativo, de 21,78%, no perÃodo de 50 dias; e as leiras sob o modo hÃbrido de 31,21%, no perÃodo de 30 dias. Durante a fase de maturaÃÃo, para as leiras que sofreram reviramento, a reduÃÃo mÃdia de Carbono foi de 50,63%, no perÃodo de 50 dias, enquanto que as demais apresentaram uma reduÃÃo mÃdia de 39,54%, no perÃodo de 60 dias. O pH se mostrou Ãcido no material e no inÃcio do processo de compostagem, em todas as leiras. Os resultados obtidos mostraram que os valores mÃdios do Ãndice pH foram aumentando de acordo com a degradaÃÃo da matÃria orgÃnica. Na fase de maturaÃÃo, o pH permaneceu na faixa alcalina em todas as leiras. Durante fase ativa, o teor de nitrogÃnio cresceu, em mÃdia, 41,12% nas leiras sob o modo positivo, 54,21% nas leiras sob o modo negativo e 32,05% nas leiras sob o modo hÃbrido. Durante fase ativa, as leiras operacionalizadas sob o modo positivo apresentaram uma reduÃÃo da relaÃÃo C/N de 47,89%, em 40 dias; as leiras sob o modo negativo, de 44,35%, em 50 dias; e as leiras sob o modo hÃbrido, de 48,33%, em 30 dias. PÃde-se observar que a relaÃÃo C/N final na fase de maturaÃÃo das leiras que foram reviradas, apresentou valores mÃdios na ordem de 10 a 15 no perÃodo de 50 dias. As leiras operacionalizadas sob o modo positivo tambÃm registraram valores dentro desta faixa, porÃm no perÃodo de 60 dias, enquanto que as leiras operacionalizadas sob o modo negativo registraram valores mÃdios superiores ao recomendado pela legislaÃÃo, tambÃm no perÃodo de 60 dias. Observou-se que em todos os sistemas os Coliformes Totais e Fecais ou Termotolerantes foram diminuindo durante a fase de aeraÃÃo (fase de degradaÃÃo ativa). As leiras operacionalizadas sob o modo positivo registraram valores de Coliformes Totais da ordem de 9,1x108 a 5,0x103 UFC. g-Âe de Coliformes Fecais da ordem de 6,2x108 a 3,1x103 UFCg-1; as leiras operacionalizadas sob o modo negativo registraram valores de Coliformes Totais da ordem de 8,4x108 a 4,8x103 UFC.g-1 e de Coliformes Fecais da ordem de 6,1x108 a 3,5x103 UFC.g-1 ; e as leiras operacionalizadas sob o modo hibrido registraram valores de Coliformes Totais da ordem de 9,2x107 a 4,1x103 UFC.g  e de Coliformes Fecais,da ordem de 5,2x108a 3,2x103 UFC.g-1 A temperatura foi o parÃmetro utilizado para avaliar a eficiÃncia do processo de compostagem, durante a fase ativa. O tÃrmino da fase de maturaÃÃo foi verificado por meio da relaÃÃo C/N. A anÃlise dos resultados obtidos para os parÃmetros fÃsicos, quÃmicos, e microbiolÃgicos nos trÃs sistemas avaliados neste trabalho permite inferir sobre o desempenho satisfatÃrio dos sistemas operacionalizados sob os modos positivo e hibrido. Com relaÃÃo à aeraÃÃo na primeira fase do processo, pode-se afirmar que seu efeito contribuiu satisfatoriamente, tanto na eliminaÃÃo de patÃgenos como na diminuiÃÃo do tempo de compostagem, acelerando a metabolizaÃÃo da matÃria orgÃnica. De posse dos resultados das anÃlises dos experimentos e interpretaÃÃo dos dados, observou-se que o sistema hÃbrido proposto neste trabalho apresentou ser mais eficiente que os demais. / In this research, it was aimed to evaluate the process of composting using the organic matter available at the bank of seedlings of the city of Sobral - CE, (horse manure and straw of carnauba) in three aeration systems: with injection of air, sucking of the air and injection and sucking in air cycle (hybrid), in compliance with the parameters recommended by Brazilian legislation in force, during the phases of active degradation and maturation. The experiment was installed with three treatments, one (01) under the positive way; one (01) under the negative way and one (01) under the hybrid way, following the proportions of 30% of horse manure and 70% of straw , for all treatments. Each treatment was repeated three (3) times, making, thus, a total of 9 (nine) parcels. It was conducted the evaluation of these processes, and it was observed mainly the influence of aeration and moisture in the performance of these techniques of treatment, on static. During the active phase, the under positive way they developed average reduction of organic matter of 26.55%, the under the negative way of 21.78%, while the, under the hybrid way of 31.21%. During the phase of maturation, it was turned three of each system of aeration. The reduction of organic matter of them was 50,63%, in 50 days; The other ones showed average reduction of 39,54%, in 60 days. During the active phase, the operated under the positive way had, on average, reduction of carbon of 26.55%, in the period of 40 days, the under the negative mode of 21.78%, in the period of 50 days, and the under the hybrid way of 31.21%, within 30 days. During the stage of maturity, for the that suffered of returning, the average reduction of carbon was 50.63%, in the period of 50 days, while the other ones showed an average decrease of 39.54%, in the period of 60 days. On all the, the pH developed in the material and in the beginning of the process of composting was acid. The results showed that the average pH was increasing according to the degradation of organic matter. At the stage of maturity, the pH remained in the alkaline range on all the. During the active phase, the content of nitrogen grown by an average of 41.12% on the under the positive way, 54.21% on the under the negative mode and 32.05% on the under the hybrid way. During the maturation, the content of nitrogen on all, regardless of the used method of aeration, presented quite different results. During active phase, the operated under the positive way showed a reduction of the C/N nitrogen of 47.89% in 40 days, the piles under the negative mode of 44.35% in 50 days; and piles under the hybrid way of 48.33%, in 30 days. It was observed that the C/N in the final stage of maturation of the that were returned, presented average values in the order of 10 to 15 in the period of 50 days. The under the operational way also recorded positive values within this range, but in the period of 60 days, while the piles under the operational mode registered negative average above the recommended by the law, in the period of 60 days. It was observed that in all the systems the Total Coliform and the Fecal Coliform were decreasing during the aeration (active phase of degradation). The under the operational mode recorded positive values of Total Coliform in the order of 9,1x108 to 5,0 x103 CFU.g-1 and of Fecal Coliform of the order of 6,2 x108 to 3,1 x103 UFCg-1, and the operational under the negative way registered values of Total Coliform in the order of 8,4 x108 to 4,8 x103 CFU.g-1 and of Fecal Coliform in the order of 6,1 x108 to 3,5 x103 CFU.g-1, and the piles under the hybrid way recorded values of Total Coliform in the order of 4,1 to 9,2 x107 and x103 CFU.g  and of Fecal Coliform, in the order of 5,2 x108 to 3,2 x103 CFU.g-1. The temperature was the factor used to evaluate the efficiency of the composting process, during the active phase. The end of the stage of maturity was verified by the C/N. The analysis of the results for the physical, chemical and microbiological systems in the three evaluated systems in this research were possible because of the satisfactory performance of the systems operated under the positive and hybrid ways. Regarding the aeration in the first phase of the trial, one can say that its effect contributed satisfactorily for the elimination of pathogens, such as decreasing the time of composting, accelerating the metabolism of organic matter. By the results of the analyses of the experiments and also the interpretation of the data, it was observed that the hybrid system of this research was more efficient than the others ones.

Globally, the forestry sector is the second largest contributor of greenhouse gases, and sustainable forest management is a major target of international environmental policy. However, there is the assumption underlying many policy recommendations that an increase in above-ground carbon stocks correspond to long term increases in ecosystem carbon stocks, the majority of which is stored in soils. We analyzed soil carbon and nitrogen dynamics in forest soils that had undergone twenty years of organic inputs manipulations as part of the Detritus Input and Removal Treatment (DIRT) network. There was no statistically significant effect of the rate of litter or root inputs on the carbon or nitrogen in bulk soil, on respiration rates of soil in laboratory incubations, on the non-hydrolyzed fraction of soil organic matter, or on any organic matter associated with any density. However, there is evidence for positive priming due to increased litter inputs; doubling the rate of litter inputs decreased C and N contents of bulk soil and decreased respiration rates of soil. Furthermore, there is evidence that roots influence soil organic matter dynamics more strongly than above-ground inputs. Both of these results trends match data from other DIRT sites, and are supported by the literature. / Graduation date: 2012

In this study, a chlorinated-solvent contaminated groundwater site was used as the study site. Multivariate statistical analysis explains the huge and complicated current situation of the original data efficiently, concisely, and explicitly; it simplifies the original data into representative factors, or bases on the similarity between data to cluster and identify clustering outcome. The statistical software SPSS 12.0 was used to perform the multivariate statistical analysis to evaluate groundwater quality characteristics of this site. Results show that 20 analytical items of groundwater quality of the study site are simplified into seven major representative factors through factor analysis, including ¡§background¡¨, ¡§salt residual¡¨, ¡§hardness¡¨, ¡§ethylene chloride¡¨, ¡§alkalinity¡¨, ¡§organic pollutant¡¨, and ¡§chloroform¡¨. The factor score diagram was drawn according to the score of monitoring well on each factor and 89.6% of the variance could be obtained. This study used cluster analysis to cluster in two phrases, the groundwater quality monitoring wells were classified into seven clusters according to the similarity of monitored data nature and the differences between clusters. The groundwater quality characteristics and pollutant distributions of each cluster out this site were evaluated. The clustering result indicates that for the sixth cluster (where monitoring well SW-6 was the representative well), the average concentrations of chlorides such as 1,1-dichloroethylene, 1,1-dichloroethane, and cis-1,2-dichloroethylene were the highest among the clusters, indicating those the groundwater of nearby area might be polluted by chlorinated organic compounds. In addition, to evaluate whether the clustering of cluster analysis were appropriate or not, discriminant analysis is used to evaluate clustering accuracy, in which seven Fisher discriminant coefficient formulas that were exclusively suitable for this location were established. Then, the observed values were substituted to Fisher discriminant coefficient formula. Result shows that the monitoring well¡¦s clusters obtained from discriminant analysis were totally identical with the result of actual cluster analysis; the accuracy were 100%. After performing cross-validation analysis, the result shows that the accuracy were 80%, indicating the use of discriminant analysis (with forecasting function) to verify the clustering result of the cluster analysis was highly accurate. After analyzing the pollution condition of this site using time trend and space distribution, it were determined to conclude that trichloroethylene and 1,1-dichloroethylene were the major concerning pollutants; the pollutants appeared to be spreading on a large scale, so it was difficult to use the existing data to evaluate the pollution source. After assessing environmental medium characteristics and pollutant distribution of the site, this study suggests that the use of insitu bioremediation, which is cost-effective, can be applied as a remedial mothod.

A study of the interactions of the specifically interacting organic compound pyridine with a model soil organic matter sorbent (Pahokee peat) was carried out from different nonaqueous organic liquid media, including neat n-hexadecane, acetonitrile, acetone and nhexadecane mixtures with either acetone or acetonitrile. Kinetic and equilibrium studies using an activity-based comparison of the organic compounds in solution was used to study the interactions of soil organic matter (SOM) and pyridine sorption capability in the various non-aqueous organic liquid media. Quantification and qualification of pyridine and the other co-solvents were done using Gas Chromatography (GC). Sorption of pyridine from neat organic solvents was not masked by sorption of the organic solvent. The apparent sorbed amount calculated from the change in solute concentration and reported on a dry weight basis was considered to represent the true sorbed concentration of pyridine in the sorbent phase. Pyridine sorption was found to be non-linear and distribution coefficients decreased with solute concentration, by approximately three times in n-hexadecane, more than five times in acetonitrile, and by ten times in acetone over the experimental concentration range. Pyridine sorption from nhexadecane was also found to be comparable with sorbed amounts from acetone, but much lower in comparison to sorption from acetonitrile. Sorption of pyridine from n-hexadecane mixtures with acetonitrile or acetone demonstrated the solvent assisted effect of pyridine sorption. Sorption uptake of pyridine increased as initial acetonitrile concentration increased, this acetonitrile assisted trend for pyridine sorption was found in the presence of a large excess of n-hexadecane. Sorbed concentrations of pyridine measured in the presence of high concentrations of acetonitrile (close to it's solubility limit) were found to be very similar to pyridine sorption from neat acetonitrile. Sorption behaviour of pyridine in n-hexadecane-acetone mixtures showed that increasing acetone concentrations had no effect on pyridine sorption. Pyridine sorbed from n-hexadecane, n-hexadecane-acetonitrile, and n-hexadecaneacetone mixtures showed a hysteretic desorption to n-hexadecane. After a series of repeated solvent extractions with solvents of increasing solvating power(1,4-dioxane, ethanol, dimethylsulfoxide), a fraction of pyridine remained bound to the peat. This nonrecoverable fraction was approximately the same for the different organic media (OA5± 0.09 in n-hexadecane suspensions, 0.57±O.12 in n-hexadecane-acetonitrile mixtures, and OA6±0.07 in n-hexadecane-acetone mixtures). Acetonitrile sorption by peat from nhexadecane was found to be very non-linear and hysteretic. The acetonitrile sorbed was almost fully recoverable, around 90%, for the initial acetonitrile concentration range varying from 0.14-0.7% by volume. However in the presence of pyridine a significant portion of acetonitrile was not recovered even after multiple extractions of polar organic solvents. Pyridine irreversible binding was not induced by acetonitrile additions and was found to occur to the same extent in both neat n-hexadecane and n-hexadecane-acetone mixtures. The solubilities of acetonitrile and acetone were determined by the flask method at 25°C using GC analysis. Solubility in volume percent for acetonitrile in n-hexadecane, 0.9±0.07, 0.57±0.02 for n-hexadecane in acetonitrile, 24.0±OA for acetone in nhexadecane, and 13 A±O.2 for n-hexadecane in acetone, were found. Log Ostwald coefficient (1.63±O.02) for acetonitrile in n-hexadecane was measured at 25°C using head space analysis and was found to be constant in the acetonitrile concentration range 0.10.8% by volume. Log Ostwald coefficient for pyridine in hexadecane used was 3.02, for the pyridine concentration range 50 mgIL-500 mg/L, this value was constant even with 0.5% by volume additions of acetonitrile. Analyses of sorption isotherms were reported on an activity basis to eliminate the effect of differential solute interactions in the solvent, calculated using the solute equilibrium concentration, the concentration of saturated vapour, and the Ostwald coefficient. Dissolution of peat components into n-hexadecane are known to be negligible. Peat components extracted after 12 hours and 3,5 months acetonitrile and acetone treatment (solid liquid ratio 1: 10) Showed 15 to 20 times less visible absorbance respectively (A. 465, 620, and 665, E4:E6 ratios using DV-Visible Spectroscopy), than the 12 hours aqueous peat extract. Quantification of the dissolved humic materials in the aqueous extract was followed using a Total Organic Carbon analyser. The study found the degree of humification to be much lower in non-aqueous organic solvent extracts (2.5 for acetone extracts, and 3 for acetonitrile extracts) than in aqueous solution extracts (8.2). / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002. / The Moshe Greidinger Scholarship Fund.