Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-12T14:56:31Z No. of bitstreams: 1 ALAIN CHARLES DE MELO ALVES - DISSERTAÇÃO (PPGEQ) 2017.pdf: 2958576 bytes, checksum: da6d8a9342aea19b0bd4eb2403563d7c (MD5) / Made available in DSpace on 2018-04-12T14:56:31Z (GMT). No. of bitstreams: 1 ALAIN CHARLES DE MELO ALVES - DISSERTAÇÃO (PPGEQ) 2017.pdf: 2958576 bytes, checksum: da6d8a9342aea19b0bd4eb2403563d7c (MD5) Previous issue date: 2017-02-17 / Capes / Os processos indústrias em sua maioria são multivariáveis e apresentam uma grande interação entre suas variáveis. A fim de reduzir essas interações algumas técnicas têm sido desenvolvidas. Análise de Componentes Independentes (ICA) tem sido uma técnica bastante promissora quando se deseja reduzir ou até mesmo eliminar o acoplamento entre as variáveis. Essa técnica é usada na separação de fontes desconhecidas. Embora já existam diversos trabalhos recentes sobre a aplicação do ICA em processos industriais, poucos são voltados para aplicação da técnica em colunas de destilação. Este trabalho estabelece uma estratégia de controle aplicado a uma coluna de destilação de alta pureza com recompressão de vapor utilizando o ICA. Além disso, o trabalho estabeleceu uma estratégia de controle para as composições de base e topo. Para tanto foi feita uma comunicação entre o Aspen Plus DynamicsTM e o Simulink/Matlab®. A comunicação foi estabelecida por meio do bloco AMSimulation. Duas estratégias de controle foram comparadas: MPC com o ICA e MPC sem o ICA. Os resultados da estratégia MPC com ICA se apresentaram mais promissoras mostrando que a técnica ICA é uma ferramenta desacoplante útil para sistemas com forte acoplamento. / The industrial processes are in its majority are multivariable and show a high number of interactions between its variables. Some techniques have been developed to target the reduction of these interactions. Independent Component Analysis (ICA) has been a very promising technique when it is desired to reduce or even eliminate the coupling between variables. The ICA technique has been utilized on the separation of unknown sources. Although there are several different studies targeting the application of ICA in industrial processes, just a few of them geared for technical applications in distillation columns. This dissertation attempts to establish a control strategy applied to a high purity distillation column with vapor recompression using the ICA. In addition, the dissertation proposes to establish a control strategy for the bottom and top of compositions. For this will be a communication between the Aspen Plus DynamicsTM and Simulink / Matlab®. The communication will be established through the AMSimulation block. Two control strategies were compared: MPC with ICA and MPC without MPC. The results of the MPC with ICA strategy were shown to be more promising, showing that the ICA technique is a useful decoupling tool for systems with strong coupling.

Orientador: Rubens Maciel Filho, Maria Regina Wolf Maciel / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-09T09:35:16Z (GMT). No. of bitstreams: 1 Custodio_AlineFerrao_D.pdf: 2173448 bytes, checksum: 27b046c8dc2de1781ef672eb1c4ab063 (MD5) Previous issue date: 2007 / Resumo: Este trabalho de tese propôs um processo para a produção de acetato de etila através da reação de esterificação do ácido acético com o etanol, utilizando conceitos de intensificação de processos e de Engenharia Verde (Zero Avoidable Pollution com renweable feedstock). A contribuição principal desta pesquisa é a proposta de uma planta conceitual com alta pureza de todas as correntes do processo, o que diminui desperdícios, de modo que o produto indesejado ou os reagentes não convertidos não estejam presentes nas correntes de saída do sistema. No processo proposto, todos os reagentes são de origem renovável. O acetato de etila é um solvente orgânico importante utilizado na produção de vernizes, de tintas, de resinas sintéticas e de agentes adesivos, sendo produzido normalmente, através da reação reversível do ácido acético com o etanol, com ácido sulfúrico com catalisador. O processo deste sistema de obtenção é bastante complexo porque o produto (acetato de etila) não é o componente mais volátil nem o menos volátil no sistema, de modo que a etapa de separação não é fácil de definir. O projeto conceitual proposto inclui um reator de tanque contínuo (CSTR) acoplado a um retificador, um decantador e duas colunas de purificação, para a água e o acetato de etila. O software comercial ASPEN PLUS® foi utilizado para a realização dos estudos do processo proposto através de simulação computacional em estado estacionário, e o simulador ASPEN DYNAMICS® foi utilizado para a simulação dinâmica / Abstract: This work proposes a process for ethyl acetate production via esterification of acetic acid with ethanol using concepts of process intensification and zero avoidable pollution. The main contribution of this work is the high-purity of all process streams, including the wastes ones, so that undesired product or unconverted reactants are not present in any throughput streams. Ethyl acetate is an important organic solvent widely used in the production of varnishes, ink, synthetic resins, and adhesive agents and it is normally produced via reversible reaction of acetic acid with ethanol, with sulfuric acid as catalyst. The process design of such system is complex because the ethyl acetate product is neither the lightest nor the heaviest component in the system, so that the separation stage is not an easy task. The proposed process design includes a continuous-stirred tank reactor (CSTR) coupled with a rectifier, a decanter and two purification columns for water and ethyl acetate. The commercial ASPEN PLUS® software was used to steady state simulation and ASPEN DYNAMICS® was used to dynamic simulation / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

Most clonal plants exhibit a modular structure at multiple levels. At the level of the organs, they are characterized by functional modules, such as, internodes, leaves, branches. At the level of the genetic individual (clone or genet), they possess independent evolutionary and physiological units (ramets). These evolutionary units arise through the widespread phenomenon of clonal reproduction, achieved in a variety of ways including rhizomes, stolons, bulbils, or lateral roots. The focus of this study was Populus tremuloides, trembling aspen, a dioecious tree that reproduces sexually by seed and asexually through lateral roots. Local forest patches in western populations of Populus tremuloides consisted largely of multiple genotypes. Multi-clonal patches were dominated by a single genotype, and in one population (Riske Creek) we found several patches (five out of 17) consisting of a single genotype. A second consequence of modularity is that during the repeated cycle of ramet birth, development and death, somatic mutations have the opportunity to occur. Eventually, the clone becomes a mosaic of mutant and non-mutant cell lineages. We found that neutral somatic mutations accumulated across 14 microsatellite loci at a rate of between 10^-6 and 10^-5 per locus per year. We suggest that neutral genetic divergence, under a star phylogeny model of clonal growth, is an alternative way to estimate clone age. Previous estimates of clone age couple the mean growth rate per year of shoots with the area covered by the clone. This assumes a positive linear relationship between clone age and clone size. We found, however, no repeatable pattern across our populations in terms of the relationship of either shape or size to the number of somatic changes. A final consequence of modularity is that during clonal growth, natural selection is relaxed for traits involving sexual function. This means that mutations deleterious to sexual function can accumulate, reducing the overall sexual fitness of a clone. We coupled neutral genetic divergence within clones with pollen fitness data to infer the rate and effect of mildly deleterious mutations. Mutations reduced relative sexual fitness in clonal aspen populations by about 0.12x10^-3 to 1.01x10^-3 per year. Furthermore, the decline in sexual function with clone age is evidence that clonal organisms are vulnerable to the effects of senescence. / Medicine, Faculty of / Medical Genetics, Department of / Graduate

The purpose of the study was to find alternatives to fences by comparing the frequency of damages on different configurations of chemical treated, mechanically protected and untreated hybrid aspen seedlings, planted on agricultural land. The study also explored whether anthropogenic disturbance (proximity to roads and buildings) had any effect on the frequency of seedlings damages. The study was conducted as a quantitative study with field measurements over the course of a year, in two sample plots with hybrid aspen seedlings planted in May 2016 in Vimmerby kommun, Kalmar län. The field data was compiled into Excel and compared for differences between treatments and proximity to anthropogenic disturbance. The result showed that seedlings closer to anthropogenic disturbance showed a lower frequency of damage. There was no significant difference between the mechanical (Taimitassu) and chemical (Arbinol B) seedling protection. The highest frequency of damages occurred in the summer, peaking in July. In conclusion, when choosing a place to plant hybrid aspen, there should be anthropogenic disturbance to minimize the frequency of browsing.

Quaking aspen (Populus tremuloides) is the most widely distributed tree in North America (Lindroth and St Clair 2013), and a keystone species in our western montane forests (Worrall et al. 2015). Aspen has become a model organism for studies of genetics and physiology in woody plants (Bradshaw et al. 2000, Taylor 2002). Aspen is also economicallyimportant (Worrall et al. 2015) – wood is harvested for various uses, its scenic beauty helps sustain the tourism economy in many areas, and it has recently been studied as a possible source of biofuel (Sannigrahi et al. 2010). Aspen is also a species of conservation concern, due to recent large-scale deterioration and decline of many aspen forests in the last two decades (Worrall et al. 2013). Several causal factors have been identified: fire suppression (Calder et al. 2011, Smith et al. 2011), increased ungulate herbivory (Kay and Bartos 2000), disease (Marchetti et al. 2011), and climate change (Worrall et al. 2013). My thesis focuses on two different biotic stressors of aspen: a fungal pathogen and ungulate herbivory. Understanding the relationship between aspen and their biotic stressors adds to our knowledge of aspen ecology and helps manage the increasing risk of decline in our aspen forests. Chapter 1 is a study of the relationship between aspen and a necrotrophic fungal pathogen (Drepanopeziza sp.) during a major disease outbreak in 2015. I quantified the relationship between Drepanopeziza infection severity and aspen leaf functional traits, including morphological, chemical and phenological traits. I found that severe Drepanopeziza infection was associated with low concentrations of a key class of herbivore defense compounds (phenolic glycosides), and strongly associated with early budbreak and leaf-out in aspen stands. The association between infection and early budbreak was likely caused by unusually rainy conditions in May of 2015, which may have exposed leaf tissue to wet conditions that favor thedispersal of Drepanopeziza spores. Chapter 2 is an experiment designed to determine whether the mode and timing of herbivory can influence aspen's defensive response. I specifically asked whether removing leaves, twigs and meristems together and removing leaves alone had unique effects on aspen sucker growth, survival, and phytochemistry. Additionally, I applied these simulated herbivory treatments to suckers on different dates to see whether early- or late-summer herbivory had greater effects on suckers. I found strong mode and timing effects on growth and survival, but not foliar chemistry.

Sixteen stands representing a range of structural variation in aspen, mixed aspen-conifer, and spruce-fir communities of the Wasatch Plateau, Utah, were censused by the sample count method. The stands were classified as eleven community types based on the understory dominants or indicator species and the cover types. Fifty bird species were recorded during the two seasons; thirty-two occurred in aspen cover, forty-four in mixed aspen-conifer cover, and twenty-two in spruce-fir. Comparisons of the composition and density of bird populations were made between uniform stands of a single life form and more structurally complex stands of either single or mixed life forms. Limiting factors in the structural characteristics of the stands were identified for birds restricted to particular stands. Low avian similarities between some aspen stands were attributed to the differences in structure between the stands. Bird species which favored the deciduous life form tended to decrease in abundance in the mixed stands as the canopy coverage of conifers increased, and they were absent in the spruce-fir stand. Coniferous forest bird species were more abundant in mixed stands with high coniferous coverage than in the aspen-dominated stands. Low individual bird numbers were found in the conifer stand of uniform small trees. Several vegetational characteristics of the stands were evaluated to determine if any was an index of forest heterogeneity predictive of bird species diversity. The habitat features of ecological relevance to most of the bird species were the size, spacing, and life form of the trees. The diversity of the distribution of diameter measurements at breast height for the tree species was predictive of bird species diversity. High diversity in the distribution of tree measurements at breast height was correlated with variation in tree height, tree canopy diameter, and the spacing of the life forms. It was therefore an index of three dimensional environmental patchiness, easily visualized by the variation in life forms and the number of stories within the stand.

Genotypic diversity within populations can have important evolutionary consequences, but the ecological effects of intraspecific genetic variation on community and ecosystem function have only been studied in a few systems. I present the results of a three-year study designed to address the ecological impacts of genotypic diversity in quaking aspen (Populus tremuloides Michx.), using aspen genotypes planted across genotypic diversity levels (monoculture and mixture) and watering treatment levels (well-watered and water-limited). First, I demonstrated that significant variation exists among genotypes for a wide range of growth, morphological and physiological traits, and quantified high heritability and coefficient of genetic variation values for those traits. This demonstrates that heritable phenotypic variation exists within an aspen population, which could potentially have community and ecosystem implications. Secondly, I collected ground-dwelling arthropods across experimental treatment levels to determine if there are any community-level implications of genotypic diversity and watering treatment. Ground-dwelling arthropods were significantly affected by the genotypic diversity × watering treatment interaction, such that arthropod taxonomic diversity was lowest in water-limited genotypic mixtures. This result runs counter to the bulk of the plant diversity-arthropod diversity literature, which predicts that plant and arthropod diversity should be positively correlated, and highlights the importance of environmental conditions in mediating the plant-arthropod diversity relationship. Lastly, I show that there are no overall effects of genotypic diversity or watering treatment on tree growth patterns. Instead, there are high levels of variation among genotypes in their responses to treatments (significant genotype × diversity × watering treatment interactions), which are often opposing in direction. I also show that there are significant collection site × diversity × watering treatment interactions, demonstrating that genotypes vary in their response to experimental treatments based in part on their original collection site conditions in the field. This study demonstrates that aspen populations contain high levels of genotypic diversity, but that the ecological effects of genotypic diversity are mediated by the environment (in this case, watering treatment) and can be considerably more complicated than found in most previous studies.

Quacking aspen (Populus tremuloides Michx.) is an iconic species in western United States that offers multiple ecosystem services, including carbon sequestration. A shift in forest cover towards coniferous species due to natural succession, land management practices, or climate change may modify soil organic carbon (SOC) dynamics and CO2 emissions. The objectives of this study were to: (i) assess the effects of overstory composition on SOC storage and stability across the aspen-conifer ecotone, (ii) use Fourier transform infrared spectroscopy attenuated total reflectance (FTIR-ATR) to assess whether SOC storage is associated with preferential adsorption of certain organic molecules to the mineral surfaces, and (iii) develop models using near-infrared reflectance spectroscopy (NIRS) to predict aspen- and conifer-derived SOC concentration. Mineral soils (0 – 15 cm) were sampled in pure and mixed aspen and conifer stands in Utah and subjected to physical fractionation to characterize SOC stability (i.e., SOC protected against microbial decomposition), long term laboratory incubations (i.e., SOC decomposability), and hot water extractions (i.e., SOC solubility). Vegetation cover had no effect on SOC storage (47.0 ± 16.5 Mg C ha−1), SOC decomposability (cumulative released CO2-C of 93.2 ± 65.4 g C g−1 C), SOC solubility (9.8 ± 7.2 mg C g−1 C). Mineral-associated SOC (MoM) content was higher under aspen (31.2 ± 15.1 Mg C ha-1) than under mixed (25.7 ± 8.8 Mg C ha−1) and conifer cover (22.8 ± 9.0 Mg C ha−1), indicating that aspen favors long-term SOC storage. FTIR-ATR spectral analysis indicated that higher MoM content under aspen is not due to higher concentration of recalcitrant compounds (e.g., aliphatic and aromatic C), but rather to stabilization of simple molecules (e.g., polysaccharides) of plant or microbial origin. NIRS models performed well during calibration-validation stage (ratio of standard deviation of reference values to standard error of prediction (RPD) ≥ 2). However, model performance decreased during independent validation (RPD = 1.2 – 1.6), probably due to the influence of soil texture, mineralogy, understory vegetation, and land history on SOC spectra. Further improvement of NIRS models could provide insight on SOC dynamics under potential conifer encroachment in semiarid montane forests.

Aspen is the most widespread deciduous tree of the western United States and the aspen type is important for water, forage, and wood products. Aspen reproduction on cutover areas was thought to be hindered by browsing and other factors, therefore a study was conducted to determine the effects of livestock, pocket gophers, disease, and snowpack damage on aspen reproduction during the first three years after clear-cutting. An enclosure was constructed and divided into nine paddocks. Controlled grazing by cattle and sheep was applied to six different paddocks during three summer periods. Three paddocks were protected from grazing. Results show that sheep utilized more sprouts than cattle, but controlled grazing by sheep or cattle did not prevent adequate aspen regeneration on good sites. Pocket gophers and disease appeared to be the most important decimating factors under controlled grazing. Sheep tended to concentrate on cutover areas so proper herding is needed to prevent misuse, especially the first and second years after initial sprouting.

No description available.