Trophic ecology is a key component in describing patterns of variation between and within populations, particularly in Arctic marine systems wherein climate change is impacting food webs. This thesis investigates the trophic ecology of Arctic char (Salvelinus alpinus) in the Cumberland Sound region using a multi-indicator approach. My data show trophic niche differences between resident and anadromous ecotypes and evidence for estuarine feeding by residents. I document a shift in the marine diet of Arctic char from zooplankton to capelin (Mallotus villosus) – a novel prey species in this region – that has occurred in less than a decade. Changes in Arctic char growth imply population-level effects of this shift; however, more research is required. Finally, I find lipid effects on δ13C and lipid-extraction effects on δ15N and δ34S for Arctic char muscle tissue. Lipid-correction models did not provide adequate δ13C estimates; thus, chemical extraction or ecotype-specific validation of models is recommended.

The purpose of this thesis is to analyse the function and the modulations of the figure of Rimbaud in the works of Rene Char, from 1927 to 1988 approximately. / This analysis, which traces the passage---from the latent to the manifest---of the figure of Rimbaud through Char's works, is situated at the junction of two series of texts, one "interior" (Char's writings on Rimbaud), the other "exterior" (twentieth-century interpretations of Rimbaud). Intertexuality, understood to mean the influence of Rimbaud on Rene Char, emerges as a reading, that is a "critique" of Rimbaud, the elaboration of a "Rimbaldian" text of which Char himself is the legatee. / What is designated in this thesis as the "metaphore Rimbaud" in the work of Rene Char refers to a process of aesthetic conceptualization rooted in the figure of Rimbaud. The "conceptual metaphor" (a notion borrowed from the works of Judith Schlanger) constructs rather than describes an interpretation. The metaphor is thus a means of intellectual invention, a heuristic act and an instrument of investigation. For Char, the metaphorical Rimbaud is the space into which he projects and imagines the work to be created. Thus, the figure of Rimbaud, through a working and reworking of discrepancies and margins, is gradually transformed by the poet and becomes, finally, a true metaphor, that is, a conceptual hypothesis which is supple and ample enough to accommodate all of Char's poetry.

Arctic charr are susceptible to cestodes like Diphyllobothrium dendriticum which are transmitted through the food web. Field studies investigating Arctic charr-Diphyllobothrium relationships often provide little data from which to fully understand Diphyllobothrium transmission or to assess their impact on copepod or fish hosts. Experimental studies may, therefore, be the only direct way to investigate these issues. The research goal of this thesis was to duplicate the D. dendriticum life cycle in the laboratory to investigate parasite development and host specificity, and to apply the experimental data to natural situations. Results indicated that at 10°C, D. dendriticum eggs develop slowly and 65 days are required for complete embryonation. In many Canadian Arctic lakes water temperatures rarely exceed 4°C, and this study has shown that at this temperature embryonation requires several months, necessitating more than one ice-free season for life cycle completion. The results also showed that embryos developed more rapidly and significantly more eggs hatched when incubated with light or aeration, results that were consistent for D. dendriticum originating from Canada and Norway. To continue the life cycle, coracidia must be consumed by suitable copepod hosts. This study showed that although D. dendriticum will infect the European copepods Cyclops scutifer and Eudiaptomus graciloides, prevalence was higher and procercoids developed more rapidly in E. graciloides. These results showed that E. graciloides is a better host for D. dendriticum than is C. scutifer, contradicting published literature. In North America, E. graciloides is not found in lakes containing D. dendriticum and no North American calanoid species have been tested to determine their host suitability to this cestode. This study identified two North American species, Diaptomus minutus and D. leptopus, which are suitable laboratory hosts. D. minutus is almost certainly a natural host for D. den

Biomass gasification may be an attractive alternative for meeting future energy demand. Although gasification is a mature technology, it has yet to be fully commercialised due to tar formation. This study focuses on the tar mitigation in gas produced in an atmospheric bubbling fluidised bed (ABFB) gasification system. Previous studies indicated significant tar variability along the system. In this work the experimental procedure has been improved for reliable results and better understanding of tar variability in the producer gas. After having introduced a new sample point for tar analysis to the system, experimental results indicated tar reduction in the gasifier, probably due to continuous accumulation of char and ash in the bed, as well as in the ceramic filter owing to thermal and catalytic effects. Iron-based materials, provided by Höganäs AB, were applied in a secondary catalytic bed reactor for tar decomposition in the producer gas. It was found that tar concentration depends on catalytic and gasification temperatures and catalyst material. When changing the gasification temperature from 850 °C to 800 °C the conditions in the producer gas also changed from reductive to oxidative, transforming the initial metallic state of catalyst into its oxidised form. It may be concluded that the catalysts in their metallic states in general exhibit a better tar cracking capacity than their corresponding oxides. Due to the low reactivity of petroleum coke, an alternative may be to convert it in combination with other fuels such as biomass. Co-gasification of petroleum coke and biomass was studied in this work. Biomass ash in the blends was found to have a catalytic effect on the reactivity of petroleum coke during co-gasification. Furthermore, this synergetic effect between biomass and petcoke was observed in the kinetics data. / <p>QC 20141022</p>

Trophic ecology is a key component in describing patterns of variation between and within populations, particularly in Arctic marine systems wherein climate change is impacting food webs. This thesis investigates the trophic ecology of Arctic char (Salvelinus alpinus) in the Cumberland Sound region using a multi-indicator approach. My data show trophic niche differences between resident and anadromous ecotypes and evidence for estuarine feeding by residents. I document a shift in the marine diet of Arctic char from zooplankton to capelin (Mallotus villosus) – a novel prey species in this region – that has occurred in less than a decade. Changes in Arctic char growth imply population-level effects of this shift; however, more research is required. Finally, I find lipid effects on δ13C and lipid-extraction effects on δ15N and δ34S for Arctic char muscle tissue. Lipid-correction models did not provide adequate δ13C estimates; thus, chemical extraction or ecotype-specific validation of models is recommended.

Due to security issues in energy supply and environmental concerns, renewable energy production from biomass becomes an increasingly important area of study. Thus, thermal conversion of biomass via pyrolysis and subsequent upgrading procedures were explored, in an attempt to convert an abundant agricultural residue, corn stover, into potential bio-fuels. Pyrolysis of corn stover was carried out at 400, 500 and 600oC and at moderate pressure. Maximum bio-char yield of 37.3 wt.% and liquid product yield of 31.4 wt.% were obtained at 400oC while the gas yield was maximum at 600oC (21.2 wt.%). Bio-char characteristics (energy content, proximate and ultimate analyses) indicated its potential as alternative solid fuel. The bio-oil mainly consisted of phenolic compounds, with significant proportions of aromatic and aliphatic compounds. The gas product has energy content ranging from 10.1 to 21.7 MJ m-3, attributed to significant quantities of methane, hydrogen and carbon dioxide. Mass and energy conversion efficiencies indicated that majority of the mass and energy contained in the feedstock was transferred to the bio-char. Fractional distillation of the bio-oil at atmospheric and reduced pressure yielded approximately 40-45 wt.% heavy distillate (180-250oC) with significantly reduced moisture and total acid number (TAN) and greater energy content. Aromatic compounds and oxygenated compounds were distributed in the light and middle fractions while phenolic compounds were concentrated in the heavy fraction. Finally, hydrotreatment of the bio-oil and the heavy distillate using noble metal catalysts such as ruthenium and palladium on carbon support at 100 bar pressure, 4 hours reaction time and 200o or 300oC showed that ruthenium performed better at the higher temperature (300oC) and was more effective than palladium, giving about 25-26% deoxygenation. The hydrotreated product from the heavy distillate with ruthenium as catalyst at 300oC had the lowest oxygen content and exhibited better product properties (lower moisture, TAN, and highest heating value), and can be a potential feedstock for co-processing with crude oils in existing refineries. Major reactions involved were conversion of phenolics to aromatics and hydrogenation of ketones to alcohols. Results showed that pyrolysis of corn stover and product upgrading produced potentially valuable sources of fuel and chemical feedstock.

Thesis (Ph. D.)--University of California, San Diego, 1998. / Vita. Includes bibliographical references (leaves 213-216).

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (p. 113-125).

Thesis (M. Sc.)--Memorial University of Newfoundland, 1997. / Restricted until November 1998. Bibliography: leaves 94-106.

Orientadores: Caio Glauco Sanchez, Anne Hélène Fostier / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-17T20:49:54Z (GMT). No. of bitstreams: 1 Figueiredo_RenataAndrade_D.pdf: 8352363 bytes, checksum: 340733555d15f8f34c549e841095bb6d (MD5) Previous issue date: 2011 / Resumo: O aproveitamento da casca de castanha de caju por meio da conversão térmica pode representar uma solução para o atual problema ambiental de descarte deste resíduo agrícola. Mediante o processo de pirólise, dependendo do tipo de biomassa, a mesma pode ser transformada em liquido, carvão e gases não condensáveis em diferentes proporções. A casca de castanha de caju triturada foi submetida à pirólise em reator de leito fixo, em escala laboratorial. Os experimentos foram realizados em atmosfera inerte (N2), variando a temperatura final (500, 700 e 900 °C) e a taxa de aquecimento (5, 10 e 15 °C/min). Os produtos líquidos (alcatrão+água), sólidos (carvão) e gasosos foram coletados avaliando-se os rendimentos e relacionando-os com os parâmetros previamente estabelecidos. Posteriormente, os produtos foram submetidos a vários testes de caracterização com o objetivo de obter informações que possam contribuir para a sua melhor utilização. O alcatrão foi analisado pela técnica de cromatografia gasosa acoplada a espectrometria de massa (CG-MS). O carvão foi submetido a testes de analise elementar, espectrometria de fluorescência de raio-X (EFRX), microscopia eletrônica de varredura (MEV) e a medida de área superficial por adsorção de N2. Os gases apos coletados foram analisados através de um cromatógrafo com detector de condutividade térmica (CG-DCT). Os resultados mostram que a taxa de aquecimento influi no rendimento e na composição dos produtos obtidos. Quanto a caracterização dos produtos sólidos, os mesmos apresentaram alto poder calorífico, podendo ser utilizado como combustível e características potenciais para serem incorporados ao solo. A fração liquida e composta basicamente de compostos fenólicos, caracterizando o alcatrão como insumo para diversas aplicações. Considerando o poder calorífico do gás produto sem nitrogênio, verifica-se que este pode ser utilizado como combustível em queima direta em caldeiras ou em motores e turbinas apos um pré-tratamento de limpeza / Abstract: The use of cashew nut shell by thermal conversion can represent a solution to the actual environmental problem of the disposal this of agricultural reject. By the process of pyrolysis, process depending on the biomass type, it can be transformed into liquid, char and non- condensable gases in different proportions. On this work, the crushed cashew nuts shells has been submitted to the pyrolysis in fixed bed reactor, at laboratory scale. The experiments have taken place into an inert atmosphere (N2), ranging the final temperature (500, 700 and 900 °C) and heating rate (5, 10 and 15 °C / min). The liquid products (tar and water), solids (char) and gases have been collected evaluating the yields and relating them to previously established parameters. Afterwards, the products have been submitted to a various characterization tests in order to obtain data that can contribute to their better use. The tar has been analyzed by gas chromatography coupled to a mass spectrometry (GC-MS). The char has been submitted to a ultimate analysis, fluorescence spectrometry X-ray (EFRX), electron microscopy of scanning (SEM) and measurement of surface area by adsorption of N2. The gases, after being collected, have been analyzed by a chromatography with thermal conductivity detector (GC-DCT). In order to check the heating rate influence on yield and composition of products obtained. The char obtained has a heating value higher and can be used as fuel characteristics and potential to be incorporated into the soil. As regards the tar composition phenolic compounds are most significant, characterizing the tar as a material for several applications. Considering the heating value of product gas without nitrogen, it appears that it can be used as fuel for direct combustion in boilers or in engines and turbines after a pre-cleaning treatment / Doutorado / Termica e Fluidos / Doutor em Engenharia Mecânica