Dissertations / Theses on the topic 'Back extraction'

Lactic acid is a fermentation-derived organic acid used in a wide range of industries, such as food processing and pharmaceuticals. Its market is expected to expand due to the worldwide concern for the environment, as it is an essential feedstock for biodegradable polymers. However, fermentation product is a very dilute, multicomponent aqueous solution. Subsequent separation, purification and concentration of organic acids is difficult because of high affinity of the acids for water. Reactive extraction is a viable alternative to classical separation techniques. Amine extractants dissolved in organic diluents are suitable agents with reasonable ranges of viscosity and density of the solvent phase. The product is obtained in an organic phase after reactive extraction. The aim of this study is to obtain equilibrium data of back extraction of lactic acid into appropriate aqueous solutions from the organic phase. Aqueous solutions of NaCl, NaOH, Na2SO4, NaNO3 and Na2CO3 were examined as back extractant in various initial concentrations (0.005 &ndash
3 M). The organic phase consists of tri-n-octylmethylammonium lactate (TOMA(La)) dissolved in either oleyl alcohol or octanol with initial concentrations between 0.1 and 0.3 M. According to results of the experiments, the level of back extraction generally increased with increasing initial salt concentration in aqueous phase and decreased with increasing initial TOMA(La) concentration in organic phase. For all salts investigated, considerable levels of back extraction were obtained. NaOH was considered as the most suitable back extractant among the salts investigated since it exhibits higher distribution coefficients, regenerates tri-n-octylmethylammonium hydroxide (TOMAOH) in the organic phase and has no adverse effect on fermentation medium when forward and backward extraction steps are coupled with the fermentation. The effect of diluent type of TOMA(La) was also investigated during the experiments and it was concluded that octanol is a better diluent since it gives higher equilibrium distribution coefficients in addition to its higher solvating power and lower viscosity. The present work is a part of a comprehensive research program aiming to collect data and develop knowledge for the design of an industrial reactive extraction process coupling forward and backward extraction of lactic acid in a single unit and integrating fermentation and product separation. The kinetic parameters should be obtained as the next step for the design of such a process.

The world’s growing population results in increased energy needs that cannot yet be fully supported by the renewable sources of energy. These modern conditions and restraints have created the need to further research methods to enhance the recovery of resources previously unavailable due to technical and/or economic reasons and to reduce the environmental impacts of using fossil fuels. In this dissertation, applications of electrokinetic phenomena for the improvement of subsurface energy resource extraction are investigated using experimental and numerical tools. Electrodialysis is proposed as a method of pre-treatment of the flow-back water produced during fracturing stage of shale gas extraction. The method targets the reduction of Total Dissolved Solids levels in the flow-back water so that it can either be treated further or be reused directly. The treatment and reuse of the flow-back water can potentially improve the sustainability of the shale gas extraction, controlling the amounts of water used and the general environmental footprint of the process. In addition, the electrically assisted oil recovery is investigated as a potential technique for the enhancement of oil extraction, especially for the case of heavy crude oil. The high viscosity and low mobility of heavy crude oil render it almost impossible or not economical to extract. The method uses the application of low electrical field (direct current) to the oil reservoir to facilitate and increase the oil recovery by taking advantage of the mechanisms involved in electrokinetic phenomena.

This research addresses the problem of automatic keyphrase extraction from large documents and back of the book indexing. The potential benefits of automating this process are far reaching, from improving information retrieval in digital libraries, to saving countless man-hours by helping professional indexers creating back of the book indexes. The dissertation introduces a new methodology to evaluate automated systems, which allows for a detailed, comparative analysis of several techniques for keyphrase extraction. We introduce and evaluate both supervised and unsupervised techniques, designed to balance the resource requirements of an automated system and the best achievable performance. Additionally, a number of novel features are proposed, including a statistical informativeness measure based on chi statistics; an encyclopedic feature that taps into the vast knowledge base of Wikipedia to establish the likelihood of a phrase referring to an informative concept; and a linguistic feature based on sophisticated semantic analysis of the text using current theories of discourse comprehension. The resulting keyphrase extraction system is shown to outperform the current state of the art in supervised keyphrase extraction by a large margin. Moreover, a fully automated back of the book indexing system based on the keyphrase extraction system was shown to lead to back of the book indexes closely resembling those created by human experts.

La tesi della ha come obiettivo la valorizzazione delle acque di scarto derivanti dalla produzione del bioetanolo da colture cerealicole dedicate. Nella prima parte si studia la produzione di VFA mediante digestione anaerobica. In seguito, sono eseguiti batch tests per valutare la conversione dei VFA in MCFA. Infine, si focalizza sul processo di dowstream per il recupero degli acidi carbossilici dal brodo di fermentazione attraverso reactive extraction e back extraction.

The master´s thesis is focused on detail calculation of back-pressure steam turbine with reactionary blades, with non-control exctraction line with electrical output 8 MW. Thermodynamic calculation of flow stage (canal) and stress calculation of rotor blade carrier of regulation stage, is carried out in firts part of master´s thesis. Preliminary turbine design and description, is carried out in second part of master´s thesis. Master´s thesis tasks has been created in EKOL spol. s.r.o.

Doutoramento em Engenharia Química
A indústria da pasta e do papel é um sector importante da economia mundial, particularmente a que assenta em espécies de Eucalyptus. No entanto, essas indústrias geram quantidades significativas de correntes secundárias de subprodutos e resíduos de biomassa que podem ser exploradas em aplicações de valor acrescentado em vez de serem queimadas para produção de energia. Um exemplo nobre pode ser a produção de ácidos triterpénicos com estruturas dos tipos lupano, oleanano e ursano, dada a sua abundância em alguns destes resíduos, em particular na casca, adotando o conceito de biorrefinaria integrada numa fábrica de pasta. Estes compostos são conhecidos pelas suas inúmeras actividades biológicas, por exemplo, antioxidante, anti-inflamatória e antitumoral, e podem encontrar aplicações em produtos de elevado valor, tais como cosméticos, nutracêuticos ou farmacêuticos. Neste sentido, o estudo das potencialidades das cascas das espécies de eucalipto mais exploradas enquanto fontes de compostos triterpénicos é um tópico relevante. Por conseguinte, foram analisados e comparados em pormenor os teores e composições em ácidos triterpénicos (TTAs) das cascas externas de várias espécies de eucalipto (E. globulus, E. grandis, E. urograndis, E. maidenii e E. nitens). Os teores dos principais TTAs identificados nestas espécies variaram entre 4.5 g/kg no E. urograndis e 21.6 g/kg no E. nitens. Observou-se que as cascas externas de Eucalyptus de zonas temperadas e Mediterrânicas, nomeadamente E. nitens e E. globulus, são mais ricas em TTAs que as espécies de regiões tropicais e subtropicais. Além disso, a casca externa do E. globulus é claramente a mais rica em ácidos com estruturas do tipo ursano enquanto a do E. nitens é a mais rica em ácidos do tipo oleanano e lupano. Estes resultados levaram-nos a estudar a extração dos TTAs da casca de Eucalyptus, bem como a sua posterior concentração e purificação, a qual foi efetuada por extração sólido-líquido convencional combinada com a precipitação de solutos, e por extração com fluidos supercríticos (SFE). No que diz respeito à primeira abordagem referida, foi desenvolvido neste trabalho um método patenteado que permite obter extratos enriquecidos em TTAs das cascas de eucalipto baseado em tecnologias disponíveis no imediato. Em relação à segunda abordagem, e de forma a apostar em processos de baixo impacto ambiental exigidos pelas biorrefinarias do futuro, a SFE surge como uma opção natural. Assim, foi efetuada a SFE da casca caduca do E. globulus com dióxido de carbono puro e modificado para recuperar a fração de TTAs, e os resultados foram comparados com os obtidos por extração em Soxhlet com diclorometano. Foram realizados estudos preliminares sobre a influência da pressão (100-200 bar), a adição de co-solvente (0, 5 e 8% m/m de etanol), e operação em múltiplos passos a fim de avaliar a aplicabilidade da alternativa supercrítica para a sua produção eficiente e selectiva. Os resultados destacaram a influência da pressão e o importante papel resumo (cont.) desempenhado pelo co-solvente neste processo, cujo efeito foi mais relevante do que o aumento da pressão em várias dezenas de bar. Este trabalho foi depois otimizado, usando o planeamento factorial de experiências e a metodologia de superfícies de resposta, para analisar a influência da temperatura (40-60 ºC), pressão (100-200 bar), e teor de etanol (0.0-5.0% m/m) na recuperação dos TTAs e respectiva concentração nos extractos. Nestes intervalos, as melhores condições de operação encontradas foram 200 bar, 40 °C e 5% de etanol, para as quais os modelos de regressão estatisticamente validados previram um rendimento de extração de 1.2% com 50% de concentração em TTAs, correspondendo ao rendimento em TTAs de 5.1 g/kg de casca e uma recuperação de 79.2% comparativamente ao valor do Soxhlet. Os TTAs livres e acetilados apresentaram tendências de extracção bastante distintas devido às suas diferentes afinidades para o CO2 causadas pelas diferentes polaridades: os derivados acetilados aproximam-se de um patamar máximo a cerca de 200 bar e 5% de etanol, enquanto a extração dos TTAs livres apresenta uma tendência sempre crescente no intervalo de condições estudado. Foram também medidas curvas cumulativas de SFE da casca do E. globulus de forma a analisar o comportamento cinético do processo em termos de rendimento total, rendimento em TTAs, rendimento em TTAs livres, rendimento em TTAs acetilados, e concentração dos TTAs nos extractos. Foi analisada a influência da pressão, temperatura, teor de co-solvente e caudal do dióxido de carbono sobre as respostas anteriores. Os dados experimentais foram modelados com os modelos Logístico, de Dessorção, de Placa Plana Simples, e de Difusão. Na globalidade, os resultados confirmaram que a pressão e o teor de etanol têm um efeito significativo sobre as curvas de extração, os rendimentos finais e as concentrações dos extratos, e mostraram a presença de limitações externas à transferência de massa em alguns ensaios. Mais uma vez, as famílias individuais de TTAs livres e acetilados apresentaram diferentes tendências de extracção. A modelação permitiu-nos confirmar não só o importante papel desempenhado pela difusão intraparticular na SFE, mas também a contribuição da resistência no filme em alguns ensaios. Após a análise de todos os resultados, foi efetuado um ensaio em duas etapas em série, possibilitando o enriquecimento do teor em TTAs no extracto devido às diferentes condições adotadas em cada etapa. Por último, um éster metílico de um ácido triterpénico do tipo oleanano - morolato de metilo - foi identificado pela primeira vez enquanto componente da casca de Eucalyptus na casca externa do Eucalyptus grandis x globulus, onde ocorre em teores elevados. A sua extração com CO2 supercrítico foi também realizada, visando a conceção de uma alternativa de extração ambientalmente benigna para este composto. A 200 bar e 60 ºC, a remoção do morolato de metilo atingiu um patamar às 6 h para 5.1 kg h-1 de CO2 / kg de casca. Em geral, e de forma semelhante à SFE da casca do E. globulus, os TTAs acetilados foram mais significativamente extraídos quando comparados com os seus ácidos livres, o que está diretamente relacionado com a natureza menos polar destas moléculas. O trabalho apresentado nesta tese é uma contribuição para a valorização de uma corrente de biomassa com baixo valor na indústria de pasta em duas vertentes complementares. Por um lado, aumentou o conhecimento da composição lipofílica das cascas de Eucalyptus spp. com interesse comercial para a produção de pasta, destacando o seu potencial enquanto fontes de ácidos triterpénicos. Por outro lado, foram desenvolvidos dois processos alternativos e facilmente integráveis numa fábrica de pasta para a sua exploração a partir da casca: um baseado em tecnologias convencionais bem estabelecidas a nível industrial, prevendo a sua aplicação a curto prazo, e um outro baseado na SFE, seguindo as tendências das futuras biorrefinarias.
The pulp and paper industries are an important sector in the world economy, particularly those based on Eucalyptus species. However these industries generate substantial amounts of by-products and biomass side streams which may be exploited in added value applications, rather than being burned for energy production. A noble example could be the production of triterpenic acids with lupane, oleanane, and ursane skeletons, by adopting the concept of a biorefinery integrated into a pulp mill, since they are highly abundant in some of those residues, particularly in the bark. These compounds are known by their innumerous biological properties, e.g. antioxidant, anti-inflammatory or antitumor, and can find valuable applications in products such as nutraceuticals, cosmetics or pharmaceuticals. In this sense, the study of the potentialities of the barks of the most exploited Eucalyptus species as sources of triterpenic compounds is an important issue. Accordingly, the analysis of the triterpenic acids (TTAs) composition of the outer barks of several Eucalyptus species (E. globulus, E. grandis, E. urograndis, E. maidenii and E. nitens) was carried and compared in detail. The contents of the main TTAs identified in these species varied between 4.5 g/kg in E. urograndis and 21.6 g/kg in E. nitens. It was observed that the outer barks from Eucalyptus of temperate and Mediterranean zones, namely E. nitens and E. globulus, are richer in TTAs than those species from sub-tropical and tropical regions. Furthermore, E. globulus outer bark is clearly the richest in ursane acids while E. nitens is the richest in oleanane and lupane acids. These results induced us to investigate the TTAs extraction from Eucalyptus bark and their further concentration and purification, which were accomplished by conventional solid-liquid extraction combined with solutes precipitation, and by supercritical fluid extraction (SFE). With respect to the first mentioned approach, a patented method for obtaining extracts enriched in TTAs from Eucalyptus barks based on readily available technologies was developed in this work. Concerning the second approach, in order to contribute for the low environmental impact processes required by future biorefineries, the SFE arises as a natural option. Hence, the SFE of E. globulus deciduous bark was performed with pure and modified carbon dioxide to recover the TTAs fraction, and the results were compared with those obtained by Soxhlet extraction with dichloromethane. The influence of pressure (100-200 bar), co-solvent content (0, 5 and 8 wt.% of ethanol), and multistep operation were preliminary studied in order to evaluate the applicability of the supercritical alternative for their selective and efficient production. Results pointed out the influence of pressure and the important role played by co-solvent, whose effect was more important than increasing pressure by several tens of bar. This work was further optimized using factorial design of experiments and the response surface abstract (cont.) methodology to analyze the influence of temperature (40-60 ºC), pressure (100- 200 bar), and ethanol content (0.0-5.0 wt.%) upon TTAs recovery and concentration in extracts. In these intervals, the best operating conditions found were 200 bar, 40ºC and 5% ethanol, for which the statistically validated regression models provided an extraction yield of 1.2% and TTAs concentration of 50%, which correspond to TTAs yield of 5.1 g/kg of bark and a recovery of 79.2% in comparison to the Soxhlet value. The trends of the free and acetylated TTAs were very different, due to their distinct CO2-philic character caused by dissimilar polarities: the acetyl derivatives approached a plateau near 200 bar and 5% ethanol, while the free TTAs extraction always increased in the range of the conditions studied. The cumulative curves of SFE of E. globulus bark were also measured in order to examine the kinetic behavior of this process in terms of total yield, TTAs yield, free TTAs yield, acetylated TTAs yield, and TTAs concentration in the extracts. The influence of pressure, temperature, co-solvent content, and carbon dioxide flow rate upon the previous responses was analyzed. The experimental curves were modeled with Logistic, Desorption, Simple Single Plate, and Diffusion models. In the whole, results confirmed that pressure and ethanol content imparted a significant effect upon extraction curves, final yields, and extracts concentrations, and showed that external limitations to mass transfer affected some runs. Once again, the individual families of free and acetylated TTAs exhibited distinct extraction trends. Modeling allowed us to confirm not only the major role played by intraparticle diffusion upon the SFE but also the contribution of film resistance in some assays. After analyzing all results, a two-step experiment in series has been performed, making possible to enrich the TTAs content in the extract due to the distinct conditions adopted in each stage. Finally, a highly abundant oleanane type triterpenic acid methyl ester – the methyl morolate – was identified for the first time as a component of Eucalyptus bark tissues in outer barks of Eucalyptus grandis x globulus. Its supercritical CO2 extraction was also carried out, aiming at designing an environmentally friendly extraction alternative for this compound. At 200 bar and 60 ºC, the methyl morolate removal attained a plateau at 6 h for 5.1 kg h-1 of CO2 / kg of bark. In the whole, and similarly to the SFE of E. globulus bark, the acetylated TTAs obtained were more significantly extracted when compared to their free acids, which is directly related with the less polar nature of the former molecules. The work presented in this thesis is a contribution for the upgrading of a low value biomass stream from the pulp industry from two complementary points of view. In one hand, it increased the knowledge of the lipophilic composition of the bark of Eucalyptus spp. with commercial interest for pulpwood, highlighting their potential as triterpenic acids sources. On the other hand, two alternative processes were developed for their exploitation from the bark, being easily integrated within a pulp mill: one based on well establish conventional technologies foreseeing its short term implementation, and another based on SFE, following the trends of future biorefineries.

Methods to extract vessel networks in medical images have been in high demand for its applications to health risk predictions. For example, vessel enhancement of retinal images has shown promises in diagnosing diabetes. Within the existing literature, multiscale vessel enhancement stands out as one of the best for its accuracy, speed, and simplicity. But like many vessel extraction techniques, the efficacy of the method is greatly hindered in the presence of noise, lighting variations, and decreased resolution. This deficiency is presents itself in retinal images and are particularly pronounced in digital photographs of human placenta.

Retinal images have a been popular data set of testing vessel extraction methods because of its simplicity in anatomical structure yet high hopes in diagnosing conditions such as diabetic retinopathy and glaucoma. Thus, the thesis will focus on the application of vessel extraction methods on retinal images. Specifically, we focus on the DRIVE and STARE database.

Also, recent placental pathology evidence has contributed to current understanding of causes of low birth weight and preterm birth, each has been linked to increased risk of later neurodevelopmental disorders. Among various factors that cause such disorders, the vessel network on the placenta has been hypothesized to offer the most clue in bridging that connection. Herein lies the most essential step of the blood vessel extraction, which has only been done manually through a laborious process.

Motivated by its ability to handle curvilinear structures, we propose the use of directional filter banks to further enhance the results obtained from the multiscale method. Validating experiments will be performed on a private database that is made available by the Placental Analytics, LLC.

It will be shown that for retinal images, the directional filter bank approach significantly improves the performance over the well-known multiscale vessel enhancement method. However, the directional filter bank approach are comparable to multiscale vessel enhancement on placentas.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
The coconut (Cocos nucifera) is a tropical fruit of high economic power in the Brazilian sphere being consumed largely in an immature stage that presents with a significant volume of coconut water. Associated with this market performance, it is remarkable the considerable amount of waste that this fruit when is consumed. The shell represents about 85% of the gross weight of the fruit and is associated with an increased resistance to degradation. The accumulation of this material contributes to the life of landfills decreases, making the problem of concern. Inserted in this issue of the reuse of biomass, coconut has been studied intended to application of high performance. Its physicochemical characterization was performed bringing the percentage of insoluble lignin result in the order of 28.27% which makes it compatible for extraction of this component. In this study, lignin was extracted from green coconut fiber for subsequent use in polyurethane. Targeting a process that does not destroys the fraction of sugars present, the process used to extract lignin was organosolv using acetic acid. The treatment showed an appreciable maximum yield of 78%, which can enable full utilization of the coconut fiber within a biorefinery approach. The lignin extracted by the method acetosolv was used as a source of hydroxyl for the production of polyurethane, since lignin is a amorphous aromatic polyphenol. Analysis by Nuclear Magnetic Resonance of Hydrogen (1H NMR) and Infrared (FTIR) showed characteristic profiles of lignin showing the extraction method was suitable for extraction of lignin. Polyurethane samples produced showed two degradation events in the ranges of 325 Â C and 400 Â C respectively, which is in agreement with the literature. Analysis by High Performance Liquid Chromatography of the solvent extraction and precipitation of lignin effluent showed the presence of furfural and hydroxymethylfurfural, where the first had a good production level of 604 mg in 10 g of coconut fiber. Thermal and spectroscopic characterizations were used to explore the behavior of the polyurethanes obtained.
O coco (cocos nucÃfera) à uma fruta tropical de elevado poder econÃmico na esfera brasileira, sendo consumido largamente no estado imaturo, fase em que se apresenta com um expressivo volume de Ãgua em seu interior. Associado a este desempenho mercadolÃgico, à notÃvel o enorme volume de resÃduo que este fruto deixa quando consumido. A casca corresponde a cerca de 85% do peso bruto do fruto e à associada a elevada resistÃncia à degradaÃÃo. O acÃmulo deste material contribui para que a vida Ãtil de aterros sanitÃrios diminua, tornando o problema preocupante. Inserido nesta temÃtica de reaproveitamento de biomassa, o coco foi estudado para se propor uma aplicaÃÃo de alto desempenho. A caracterizaÃÃo fÃsico-quÃmica do mesmo foi realizada, obtendo-se resultado percentual de lignina insolÃvel da ordem de 28,27% o que o torna compatÃvel para extraÃÃo deste componente. No presente trabalho, lignina foi extraÃda de fibras de coco verde para posterior utilizaÃÃo em poliuretano. Visando um processo que nÃo inutilizasse a fraÃÃo de aÃÃcares presentes, o processo utilizado para extraÃÃo de lignina foi o organossolve com a utilizaÃÃo de Ãcido acÃtico. O tratamento realizado mostrou um rendimento mÃximo apreciÃvel de 78%, o que pode possibilitar o aproveitamento integral da fibra de coco dentro de uma abordagem de biorrefinaria. A lignina extraÃda pelo processo acetossolve, foi utilizada como fonte de hidroxilas para produÃÃo de poliuretano, uma vez que a lignina consiste em um polifenol aromÃtico amorfo. As anÃlises por RessonÃncia MagnÃtica Nuclear de HidrogÃnio (NMR 1H) e Infravermelho (FTIR) apresentaram perfis caracterÃsticos da lignina, mostrando que o mÃtodo empregado foi adequado para a sua extraÃÃo. As amostras de poliuretano produzidas presentaram dois eventos de degradaÃÃo nas temperaturas de 325ÂC e 400ÂC, o que està de acordo com a literatura. A anÃlise por Cromatografia LÃquida de Alta EficiÃncia do solvente de extraÃÃo e do efluente de precipitaÃÃo da lignina mostrou a presenÃa de furfural e hidroximetilfurfural onde o primeiro apresentou um bom nÃvel de produÃÃo de 604mg em cada 10 g de fibra de coco. A termogravimetria mostrou 2 eventos caracterÃsticos de degradaÃÃo na regiÃo de 320 e 400ÂC e a anÃlise por FTIR mostrou uma reaÃÃo completa de grupos isocianatos.

When coring thick-barked trees, increment cores often become compressed and jammed inside the narrow region of the borer shaft. These jams can be problematic for two reasons: first, it often leaves the core unusable; second, the jam may be so tightly compressed in the borer that removal is difficult, especially in the field. Although procedures to evacuate these jams are documented in the literature, methods of prevention are not. Here, a modified manual method of increment boring that can reduce the likelihood of jams and, in addition, decrease the number of deformed core samples is described. Traditional and modified boring methods were randomly assigned to 40 Douglas-fir trees (80 cores) at a research site along the Oregon coast. Results show that jams were associated with traditional boring over six times more than with the proposed modified technique.

The objective of this study was to determine the effectiveness of suction cup lysimeters (SCL) in extracting substrate solution from pine bark substrates. Lysimeter types tested were 4.8-cm diameter with a ½ or 1-bar air-entry value (AEV) and 2.2-cm diameter also with a ½ or 1-bar AEV. Sufficient volume could be obtained when a vacuum pressure of 30, 40 or 50 cb was applied to lysimeters with a minimum extraction time of five minutes. The 2.2-cm lysimeters were found to be suitable for extracting solution if smaller sample volumes were needed. To determine effect of vacuum pressure and extraction time on volume extracted, the 4.8-cm ½-bar lysimeters were installed in containers with pine bark substrate and Quercus phellos L. (willow oak) trees. Volumes extracted were somewhat erratic and not strongly dependent upon centibars of vacuum or extraction time. Lysimeters immersed in water demonstrated that variability was not due to individual lysimeters, but to the coarse nature of the pine bark substrate. Substrate EC levels were not affected when volume of substrate solution extracted by the SCL's varied from 10 to190 ml.â To determine the effectiveness of SCL's to monitor nutrient status of container-grown shade trees, two-year-old container-grown willow oak trees were grown in a pine bark substrate and fertilized with 0, 50, 100, 150, 200, 250 or 300 grams Osmocote Plus Northern (15N â 3.9P â 9.8K). Plant height and trunk diameter increased with up to 200 grams of Osmocote per container. There was a good relationship between solution EC and plant growth
Master of Science

Intresset för användningen av material från förnybara råvaror ökar. Produktionen av vedmassa och material i skogsindustrin genererar dagligen stora mängder biprodukter, särskilt bark. Barken innehåller många värdefulla komponenter som kan förädlas och öka värdet för barken, men först måste de separeras. Målet med denna undersökning var att separera dessa genom att jämföra två olika typer av extraktionsmetoder. Den första metoden använde programmerbar utrustning som namnges accelerated solvent extraction (ASE) och den andra använde manuell teknik som namnges Soxhlet extraktion. Syftet med undersökningen var att avgöra vilken extraktionsmetod som kan användas till att utvinna bark komponenter mest effektivt. Metoden ASE omfattar acetonextraktion och varmvattenextraktion där trycket var 100 bar, temperaturen 100oC och tiden drygt en timme. Soxhletextraktion omfattade enbart acetonextraktion under atmosfäriskt tryck, kontinuerlig värme och tiden 90 minuter. ASE-metoden gav fyra extrakt; acetonextrakt vid 100oC samt varmvattenextrakt vid 100oC, 140oC och 160oC.  Barken som studerades var uppdelad i två fraktioner, fuktig bark och torr bark. En beräkning av utbyte % utfördes efter varje extraktion. Extrakten från fuktig bark hade mörkare färg än extrakten från torr bark. Det uppmätes pH-värden för alla vattenextrakt och den som gav lägst pH var vattenextrakt som erhölls vid 160oC. Slutligen visade utbyteresultaten inga stora skillnader mellan de utförda ASE vattenextraktionerna exklusive extraktfärgen som kan vara en indikation till skillnad i extraherade molekyler. Användningen av sand under varmvattenextraktionerna gav inga förbättringar i extraktionsmetoden.
Interest in the use of materials from renewable sources is increasing. The production of wood pulp and materials in the forest industry generates large amounts of by- products daily, especially tree bark. Bark contains many valuable components which if separated can be used in various types of applications. The aim of this study was to compare two extraction methods. The first method used programmable equipment and is named accelerated solvent extraction (ASE) and the second used manual technology and is named Soxhlet extraction.  The purpose of the study was to determine which extraction method can be used to extract bark components more efficiently. The ASE method included acetone extraction and hot water extraction where the pressure was 100 bar, the temperature 100oC and the time just over an hour. Soxhlet extraction involved only acetone extraction under atmospheric pressure, continuous heating, and a time of 90 minutes. The ASE method yielded four extracts: acetone extract at 100oC and hot water extract at 100oC, 140oC and 160oC.  The bark studied was divided into two parts, undried bark and dry bark. Total calculation of yield% was performed after each extraction. The extracts from undried bark had a darker color than the extracts from dry bark. The pH values were measured for all water extracts and the one that gave the lowest pH was obtained at 160oC. Finally, the extraction results did not show any major differences between the ASE water extractions performed excluding the extract color which may be an indication of difference in extracted molecules. The use of sand during the hot water extractions did not improve the extraction method.

Content: Traditional chromium tanning agents cannot conform to the requirement of sustainable and cleaner development under current leather producing. Compared with chromium tanning agents, vegetable tanning agents have been widely used in tanning process by the virtue of its non-toxicity, low pollution, biodegradability and regenerability. In this study, a novel vegetable tanning agent was extracted from the Coriaria nepalensis bark (CNB) by alkali solution. In order to optimize extraction conditions, the response surface Box-Behnken design was used in this experiment. The key factors including alkali concentration, extraction time, extraction temperature, liquid to solid ratio and extraction times. The experimental results showed that under the conditions of 0.22% sodium hydroxide concentration, 63 min extraction time, 83℃ extraction temperature and 24 liquid to solid ratio, the yield of tannins in CNB is 15%, tannins in extractives up to 50%. Afterwards, the composition and molecular mass were evaluated, we discovered that the extractives belong to hydrolyzable tannins and its molecular mass ranged from 599 to 1457 Da. Furthermore, the extractives were used in sheep garment tanning process. The results showed that the shrinking temperature of tanned leather can reach to 75 ℃. Applying the extractives to the retanning process, the shrinking temperature of retanned leather can reach to 130 ℃. Surprisingly, the color of tanned or retanned leather coincide with the requirement of light leather. Take-Away: 1 New vegetable tanning agent from Coriaria nepalensis bark. 2 The vegetable tanning agent belongs to hydrolyzable tannins and its molecular mass ranged from 599 to 1457 Da. 3 The shrinking temperature of tanned leather and retanned leather can reach to 75 ℃ and 130 ℃ respectively.

Cette étude a deux objectifs principaux : l’extraction de tanins condensés d’écorces de pin maritime et la formulation de colles tanin-lignosulfonate. Deux méthodes d’extraction ont été étudiées. La première est une extraction à l’eau chaude ; c’est une technique simple, peu coûteuse, sans solvant. La deuxième est une extraction assistée par micro-ondes ; c’est une technique innovante, rapide et peu consommatrice en solvant. L’optimisation des conditions d’extraction à l’eau chaude a été réalisée. Les extraits ont été caractérisés par des dosages colorimétriques, leur réactivité au formaldéhyde, par infrarouge à transformée de Fourier (IRTF), par chromatographie en phase liquide à haute pression, par 1H RMN et 2D HSQC RMN. L’impact de la granulométrie sur l’extraction de polyphénols et particulièrement de tanins condensés par extraction assistée par micro-ondes a été étudié pour la première fois. Les deux types d’extraction ont été comparés. L’extraction assistée par micro-ondes a un rendement en extractibles inférieur à l’extraction à l’eau chaude. Mais elle extrait plus de tanins condensés, de flavonoïdes simples et plus de sucres. Quelle que soit la méthode d’extraction, les tanins condensés majoriatires extraits de l’écorce de pin maritime sont de la catéchine, de l’épicatéchine, de l’épicatéchine gallate et de l’épigallocatéchine. Des colles tanin-lignosulfonate ont été produites en utilisant l’héxaméthylènetetramine comme durcisseur. Dans un premier temps, des tanins de mimosa ont été utilisés avec des lignosulfonates de sodium et des lignosulfonates d’ammonium. Les lignosulfonates ont subi deux traitements au glyoxal qui ont été comparés par analyse thermogravimétrique (ATG), par calorimétrie différentielle à balayage (DSC), par les propriétés thermiques et mécaniques de colles et de panneaux de particules avec des lignosulfonates ayant subi les deux traitements ont également été étudiées. L’optimisation du ratio tanin de mimosa-lignosulfonate glyoxalé a été menée et les propriétés thermiques des colles mesurées. L’optimisation des conditions de pressage de panneaux de particules a été réalisée. Des panneaux de particules avec de bonnes performances mécaniques ont été fabriqués. Des colles à base de tanins d’écorce de pin maritime et de lignosulfonates ont été réalisées avec 40% de tanins et 60% de lignosulfonates. Ces colles ont été caractérisées par IRTF, analyse thermomécanique, ATG et DSC. Ces colles sont rentrées dans la fabrication de panneaux de particules. Les émissions de formaldéhyde et la cohésion interne des panneaux ont été mesurées et comparées à des panneaux encollés avec une colle tanin de mimosa-lignosulfonate et une résine urée-formaldéhyde. Grâce à ces résultats, il a été possible de montrer que les panneaux de particules fabriqués à partir de colles bio-sourcées n’émettaient pas de formaldéhyde
This study has two main objectives: the extraction of condensed tannins from maritime pine bark and the preparation of tannin-lignosulfonate adhesives. Two extraction methods were studied. The first is hot water extraction which is a simple, cheap method without the use of an organic solvent. The second is microwave-assisted extraction which is a fast, innovative method using only a small amount of solvent. Optimum extraction conditions were determined for hot water extraction. The extracts were characterised by their reaction to formaldehyde and by using colorimetric tests, Fourier Transformed Infrared spectroscopy (FTIR), high pressure liquid chromatography, 1H NMR and heteronuclear single quantum correlation 2D NMR.. The two types of extraction were compared. It was found that microwave-assisted extraction produced a lower yield of extractibles than the hot water method but that it produced more condensed tannins, simple flavonoids and sugars. The condensed tannins extracted from maritime pine bark are catechin, epicatechin, epicatechin gallate and epigallocatechin, whatever the extraction method used. Tannin-lignosulfonate adhesives were produced using hexamethylenetetramine as a hardener. First, mimosa tannins were used with sodium lignosulfonates and ammonium lignosulfonates. The lignosulfonates underwent two glyoxal treatments which were compared using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and by determining the thermal and mechanical properties of the adhesives and of the particle boards made using the lignosulfonates resulting from the two treatments. The optimum mimosa tannin-glyoxalated lignosulfonate ratio was determined and the thermal properties of the adhesives were measured. The optimum conditions of pressing the particle boards were determined. Particle boards which recorded a good mechanical performance were produced. Adhesives using maritime pine bark tannins and lignosulfonates were prepared with 40% tannins and 60% lignosulfonates. These adhesives were characterised using FTIR, thermomechanical analysis, TGA and DSC. These adhesives were used to produce particle boards. The emission of formaldehyde and the internal bond of the boards were measured and compared to those of boards made with a mimosa tannin-lignosulfonate adhesive and to those of boards made with a urea-formaldehyde resin. Thanks to these results, we were able to produce particleboards with bio-based adhesives that didn’t emit formaldehyde

Reproduction de : Thèse de doctorat : Genie des procédés et de l'environnement : Toulouse, INPT : 2006. Reproduction de : Thèse de doctorat : Genie des procédés et de l'environnement : Budapest, Université des Sciences techniques et économiques : 2006.
Thèse soutenue en co-tutelle. Titre provenant de l'écran-titre. Bibliogr. 110 réf.

La thèse est consacrée à l'étude de deux procédés hybrides importants du point de vue de l'intensification des procédés : la distillation extractive discontinue (DED) et la distillation reactive discontinue (DRD). La faisabilité de la séparation d'un mélange azéotropique à maximum a été montrée en utilisant un solvant intermédiaire dans une configuration traditionnelle de la DED. Une nouvelle configuration avec une alimentation inversée est présentée et sa plus grande efficacité a été prouvée. Une méthode de faisabilité générale est développée dans la deuxième partie de la thèse pour la DRD. La déduction des équations de modèle et un algorithme pour les résoudre sont présentés. La nouvelle méthodologie a été validée sur deux systèmes réactifs. Les résultats ont été validés par des simulations dans les deux cas et expérimentalement pour la DED
The thesis deals with two hybrid processes from the viewpoint of feasibility : batch extractive distillation (BED) and batch reactive distillation (BRD). Both processes are important from the viewpoint of process intensification. Separation of a maximum boiling azeotrope with intermediate boiling entrainer and the traditional BED configuration is found feasible. A novel configuration of BED, namely the inversed-fed BED (IBED), is also proposed and found more efficient for the studied mixture than the traditional one. Sensitivity analyses are performed for both configurations with commercial simulator (ChemCAD). Feasibility of the BED configuration is validated experimentally, as well. A general feasibility method of BRD is presented in the second part of the thesis. The derivation of the reactive model equations and their solution algorithm is presented. The new methodology is presented on two reactive systems, and the main results are validated by dynamic simulation runs

Cette étude présente une dimension économique, sociale et environnementale très importante. Elle rentre dans le cadre du projet Franco-Marocain PHC Toubkal (Ecopama, Volubilis 2012). Son objectif majeur est de valoriser les écorces Marocaine d’Acacia mollissima par une extraction verte permettant l’obtention des produits réactifs, des tanins condensés, qui seront utilisés dans le collage des panneaux de contreplaqués. Trois méthodes d’extraction ont été étudiées. Deux sont conventionnelles, une macération et une infusion ; ces deux techniques d’extraction sont simples, peu coûteuses. La troisième est une extraction assistée par micro-ondes ; c’est une technique innovante, rapide et peu consommatrice en solvant. La méthodologie des plans d’expériences est utilisée dans cette étude pour déterminer les facteurs les plus significatifs pour l’amélioration du rendement d’extraction des tanins condensés, optimiser les conditions d’extractions, réduire la proportion de solvant utilisé ainsi que le temps d’extraction. L’impact des conditions d’extraction et des méthodes d’extraction sur la teneur des tanins condensés sont étudiés pour la première fois pour les écorces d’Acacia mollissima du Maroc. Les extraits ont été caractérisés par des dosages colorimétriques, par des analyses structurales et thermiques. Les trois méthodes d’extraction ont été comparées. La teneur des extractibles est affectée par la proportion de solvant utilisé et le temps d’extraction. L’extraction assistée par micro-onde présente des teneurs en tanins condensés supérieure à l’extraction par des méthodes conventionnelles mais la teneur en sucre extraits est aussi élevée. Des formulations de colles à base de tanin et de lignosulfonate ont été élaborées en utilisant l’hexamine comme durcisseur. La colle biosourcée et ses constituants ont été caractérisés par analyse thermogravimétrique (ATG), et par calorimétrie différentielle à balayage (DSC). Les propriétés thermomécaniques et mécaniques des colles élaborées sont évaluées. L’optimisation des conditions de pressage des panneaux de contreplaqués, ainsi que le ratio tanin-lignosulfonate glyoxalé, ont été réalisées. La résistance des panneaux à l’eau froide et chaude est améliorée par l’addition de la résine époxy aux formulations de colle. Les propriétés mécaniques des panneaux de contreplaqués encollés ont été évalués par des tests normatifs et ont été comparés à celle des résines synthétiques commerciales (urée formaldéhyde et phénol formaldéhyde). La qualité de collage des panneaux élaborés a été évaluée. Les différentes colles présentent des caractéristiques physiques et thermiques satisfaisantes et acceptables pour les industries de collage des panneaux de bois. Des panneaux de contreplaqués avec de bonnes performances mécaniques et une excellente résistance à l’eau froide et bouillante ont été fabriqués. Ces colles présentent une qualité de collage qui se rapproche de celle des résines phénol-formaldéhyde, et peuvent être utilisées avec succès, pour une application industrielle des panneaux de contreplaqués, en milieu sec, humide et extérieur
This study has an important economical, social and environmental dimension. It was conducted within the framework Franco-Moroccan PHC Toubkal "Ecopama, Volubilis 2012". The desire to enhance Moroccan bark of Acacia mollissima by the use of green extraction and also to obtain reagent products, condensed tannins, was the main objective of this study. These tannins will be used in the bonding of plywood panels. Three extraction methods were studied. Two are conventional, maceration and infusion; witch is simple and cheap extraction method. The third is microwave assisted extraction which is a fast, innovative method using a small amount of solvent. The experimental design methodology was used to identify the significant factors to improve yield extraction of condensed tannins, to optimize extraction process, to reduce solvent proportion and time extraction. The impact of extraction conditions and extraction process were studied for the first time on condensed tannins contents extracted from Moroccan bark of Acacia mollissima. The extracts were characterized using colorimetric assays, structural and thermal analysis.The three types of extraction were compared. The extractibles contents were affected by solvent proportion and also time extraction. Microwave assisted extraction produced a higher condensed tannins than the conventional method but in the other hand the sugars extracted is more important. Tannin-lignosulfonate adhesives were produced using hexamine as a hardener. The biobased adhesive formulations and their compounds were compared using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and by determining the thermal and mechanical proprieties of the adhesives. Optimal tannin-glyoxalated lignosulfonates ratio and pressing conditions of plywood panels were measured. The resistance of plywood panels to the cold and hot water was improved by the addition of epoxy resin in adhesive formulations. Mechanical properties of plywood panels made with tannin-lignosulfonates-epoxy adhesives were evaluated using normative standard and compared to those of panels made with a commercial resins (urea formaldehyde and phenol formaldehyde). The bonding quality of plywood panels elaborated was evaluated. The various adhesives elaborated have satisfactory and acceptable physical and thermal characteristics for bonding panels used in wood industries. Plywood panels with good mechanical performance, good resistance to cold water and to boiling water, were produced. The bonding quality of the adhesives elaborated in laboratory scale presented approximate proprieties than the phenol-formaldehyde resins which can use with successfully in dry, wet and exterior industrial application of plywood panels

Waste water containing high concentrations of dissolved metals were delivered to the environmental company SAKAB. After standard treatment procedure, involving regulation of pH and addition of flocculation agents, the water still contained nickel concentrations of 26 mg/l. Since SAKAB’s regulatory concentration limit value for nickel in outgoing water is 0.5 mg/l, further treatment was necessary. According to the supplier of the water, a complexing agent similar to EDTA had been added to the water. The aim of this study was to decrease concentrations of nickel, zinc and copper. One part of this study was the precipitation experiments as hydroxide, sulphide and adsorption to hydrous ferric oxide. The other part was adsorption to natural, organic materials such as peat, wood chips and one commercial bark compost. Adsorption to hydrous ferric oxide was the most efficient of the precipitation experiments. When 2000 mg FeCl3 was added to 100 ml waste water and pH of the solution was adjusted to pH 8, a decrease up to 74 % of total nickel concentrations was achieved. Most efficient of the adsorption experiments were the one with commercial bark compost which decreased nickel concentrations in solution up to 94 % after 20 hours of agitation.

This thesis draws on David Harvey’s concept of “accumulation by dispossession” and an international political economy (IPE) approach centred on the institutional arrangements and power structures that privilege certain actors and values, in order to critique current capitalist practices of primitive accumulation by the global corporate extractive industry. The thesis examines how accumulation by dispossession by the global extractive industry is facilitated by the “free entry” or “free mining” principle. It does so by focusing on Canada as a leader in the global extractive industry and the spread of this country’s mining laws to other countries – in other words, the transnationalisation of norms in the global extractive industry – so as to maintain a consistent and familiar operating environment for Canadian extractive companies. The transnationalisation of norms is further promoted by key international institutions such as the World Bank, which is also the world’s largest development lender and also plays a key role in shaping the regulations that govern natural resource extraction. The thesis briefly investigates some Canadian examples of resource extraction projects, in order to demonstrate the weaknesses of Canadian mining laws, particularly the lack of protection of landowners’ rights under the free entry system and the subsequent need for “free, prior and informed consent” (FPIC). The thesis also considers some of the challenges to the adoption and implementation of the right to FPIC. These challenges include embedded institutional structures like the free entry mining system, international political economy (IPE) as shaped by international institutions and powerful corporations, as well as concerns regarding ‘local’ power structures or the legitimacy of representatives of communities affected by extractive projects. The thesis concludes that in order for Canada to be truly recognized as a leader in the global extractive industry, it must establish legal norms domestically to ensure that Canadian mining companies and residents can be held accountable when there is evidence of environmental and/or human rights violations associated with the activities of Canadian mining companies abroad. The thesis also concludes that Canada needs to address underlying structural issues such as the free entry mining system and implement FPIC, in order to curb “accumulation by dispossession” by the extractive industry, both domestically and abroad.

Malgré l’enclavement du Tchad, le besoin de développement économique et social a conduit l’Etat à mettre en exploitation les gisements pétrolifères. Ces gisements étant ni « délocalisables », ni « déterritorilisables », leur exploitation dans un contexte on-shore, dans des milieux naturels et à vocation agropastorale pose des problèmes spécifiques que jusque-là le droit international et la plupart des systèmes juridiques des pays en développement peinent à saisir. Il s’agit notamment des problèmes liés à l’empreinte écologique et sociale des industries pétrolières on-shore. La prise en compte des préoccupations environnementales par le droit tchadien du pétrole est très embryonnaire et infime. Le droit tchadien de l’environnement et le droit foncier n’ont pas, non plus, pris en compte les risques liés à la recherche, l’exploitation et le transport par canalisation des hydrocarbures dans leurs dispositifs. Ils n’abordent pas aussi les problématiques relatives à la remise en l’état des sites pétroliers abandonnés ou en fin de vie. Dans un tel contexte, si le législateur ne procède pas à des reformes afin de prendre concomitamment en compte les opérations pétrolières et les préoccupations environnementales dans un dispositif juridique intégré, on risque d’assister à « un second Delta du Niger dans le bassin pétrolier de Doba »
Despite the isolation of Chad, the need for economic and social development led the government of Chad to explore and produce oil reserves. As these deposits are neither "delocalizable or movable" nor "deteriorisable or destructible", their exploitation in onshore context and natural environments with breeding vocation raises specific problems that international law and most legal systems in developing countries have difficulties to overcome until now. These include issues related to the ecological and social’s footprint of onshore oil industries. The Chadian’s law related to oil is still tiny and is at its embryonic level therefore it doesn’t take into consideration detailed environmental concerns. Chad's environmental law and land’s law didn’t also take into account risks associated with the exploration, exploitation and transport by pipeline of hydrocarbons in their plans. They also didn’t address issues related to the restoration of abandoned or end-of-life’s oilfields. In this context, if the legislator does not carry out reforms in order to simultaneously take into account petroleum operations and environmental concerns in an integrated legal system, there is a risk of "a second Niger Delta in Doba’s oilfield"

碩士
國立臺北科技大學
商業自動化與管理研究所
91
Artificial neural network (ANN) is machine learning technology. And back-propagation neural network (BPN) is one of the most popular learning paradigms of the network models.Despite the wide application and powerful capacity, A large number of inputs also dramatically increase the computational cost in learning phase. In this paper, we simplify the process of variable extraction and interpret the relative importance between variables. On the basis of back-propagation neural network (BPN), our improvement model which exchanged the input layer for output layer decreases convergent time, so that input variables can be extracted without training first in full model. In addition, we can extract approximate variables with variable extract model. . In conclusion, the accuracy between full model and reduced model which we develop is very close, and sometimes reduced model is even better than full model. Moreover, variable extraction model has converged quickly though the operating time is longer than full model. There are two contributions in our method: saving operation time and extracting variables effectively.

碩士
國立雲林科技大學
工業工程與管理系
102
Appendicitis is the most common cause of acute surgical abdomen in Emergency Room (ER).In the early, the acute appendicitis are similar with peritonitis, genital diseases of female, gastrointestinal disease and urinary disease. According to the literature review the percentage of negative appendectomies has been reported to vary in 25% to50 %. The important factors that influence the acute appendicitis were applied based on the index of symptoms, signs and laboratory data were applied in feature extraction with principal component analysis. Also, back propagation neural network and support vector machines combined with principal component analysis were used to establish the prediction model for acute appendicitis. 188 appendectomy cases form regional hospital located in southern Taiwan from were used to test to proposed system by four-fold cross validation. The result indicates that the proposed back propagation neural network combined with integrated type of principal component analysis is the best method to predict acute appendicitis, and the accuracy reaches 95.74%. This computer aided clinical evaluation system can help the hospital to decrease the numbers unnecessary operation of the derivative cost and dissension, assist the doctor to balance the rate of ruptured or negative appendectomies and the uncertainty of operation, and reduce the anxiety for the patient and their family.

碩士
國立中央大學
電機工程學系
103
The theme of this thesis is to improve the part of feature extraction in the speech keyword recognition. In the framework of the entire keyword recognition system, feature extraction is to highlight the individual features of different voices, and can reduce the amount of data by means of the extract process. Many researchers have presented different ways to extract the speech features in the literature, or on which making improvements at extracting feature coefficient method. 　　This thesis discusses several improved filter bank in mel-frequency cepstral coefficients (MFCC). The best filter bank is used to replace the original mel-triangular filter set. The experimental results showed that the application of this improved filter bank can effectively improve the recognition rate of the keyword extraction system.

碩士
逢甲大學
通訊工程所
93
The purpose of this thesis is to develop a scheme of texture analysis and reconstruction based on a Gabor filter bank. The peak frequency components of a given texture are extracted from the outputs of the Gabor filter bank in the spatial and spatio-frequency domain. The extraction process could be implemented by either a supervised or non-supervised manner. Grouping the extracted peak frequency components facilitates the texture segmentation procedure. Provided with the parameters of the peak frequency components for a given texture, the texture image is approximately reconstructed by applying the frame theory.

碩士
逢甲大學
通訊工程所
93
Edge detection provides a representation that is used by all later stages of image processing. An edge representation must be perceptually complete. This means that a perceptually accurate estimate of the original image can be reconstructed from its edges. We present an algorithm for image reconstruction from edges using a redundant filter bank derived by a wavelet frame composed of derivatives of Gaussian functions. Edges of an image can be extracted by any edge detection method. The band-pass filtered image from this filter bank contains complete information of the original image. A two-stage scheme of image reconstruction from edges is established. First, the band-pass filtered image is approximated by a set of elementary functions specified by the initial edge parameters. The elementary functions comprise of the first three orders of Gaussian derivatives. Second, the optimally approximated band-pass filtered image plus the average of the image is applied to reconstruct the original image. We adopt a conjugate gradient algorithm for the reconstruction. Furthermore, the redundant filter bank is applied to irregular sampling of the original image. The sampled pixels are determined by the positions of valleys and ridges in the band-pass filtered image. The image can be reconstructed by an iterative interpolation method. The major contributions of this thesis are to lay down a theory of edge-based image reconstruction scheme and to provide an irregular sampling method.

碩士
逢甲大學
通訊工程所
96
The purpose of the thesis is to develop image representation schemes based on the filter bank of Gaussian derivative wavelets. The band-pass image from this filter bank contains complete information of the original image. This means that the original image can be reconstructed from the band-pass image plus the average of the image by a conjugate gradient algorithm. Two types of features characterized by zero-crossings and ridge-valley extremes are extracted from the band-pass image. We propose two image representation schemes described by zero-crossings and ridge-valley extremes, respectively. Methods of image analysis and synthesis based on these two representation schemes are developed. We have applied the zero-crossings representation scheme to evaluate the performances of different edge and contour detection methods. It is also suggested that zero-crossings are appropriate to describe the brightness contours. On the contrary, textures should be characterized by peak-valley extremes.

Phenol formaldehyde (PF) resol resins have long been used widely as wood adhesives due to their excellent bonding performance, water resistance and durability. With the growing concern for fossil fuel depletion and climate change, there is a strong interest in exploring renewable biomass materials as substitutes for petroleum-based feedstock. Bark, rich in phenolic compounds, has demonstrated potential to partially substitute phenol in synthesizing bio-based PF resins. In this study, acid-catalyzed phenol liquefaction and alkaline extraction were used to convert mountain pine beetle (MPB; Dendroctonus ponderosae) infested lodgepole pine (Pinus contorta) barks to phenol substitutes, liquefied bark and bark extractives. Two types of bio-based phenol formaldehyde (PF) resol resins, namely liquefied bark-PF resin and bark extractive-PF resins, were then synthesized and characterized. It was found that acid-catalyzed phenol liquefaction and alkaline extraction were effective conversion methods to obtain phenol substitute with the maximum yield of 85% and 68%, respectively. The bio-based PF resol resins had higher molecular weights, higher polydispersity indices, shorter gel times, and faster curing rates than the lab synthesized control PF resin without the bark components. Based on the lap-shear tests, the bio-based PF resol resins exhibited comparable wet and dry bonding strength to lab PF resin and commercial PF resin. The post-curing thermal stability of the bio-based PF resins was similar to the lab control PF resin. The liquid-state 13C nuclear magnetic resonance (NMR) study revealed significant influences on the resin structures by the inclusion of the bark components. Methylene ether bridges, which were absent in the lab PF resin, were found in the bio-based PF resins. The bark components favored the formation of para-ortho methylene linkages in the bio-based bark extractive-PF resins. The liquefied bark-PF resin showed a higher ratio of para-para/ortho-para methylene link (-CH2-), a higher unsubstituted/substituted hydrogen (-H/-CH2OH) ratio and a higher methylol/methylene (-CH2OH/-CH2-) ratio than the bark extractive-PF resin. Both tannin components of bark alkaline extractives and phenolated barks contributed to the acceleration of the curing rate of the bio-based resins. This research demonstrated the promise of the bio-based PF resins containing either bark alkaline extractives or liquefied barks as environmentally friendly alternatives to PF adhesives derived solely from fossil fuel based phenol and proposed a novel higher value-added application of the largely available barks from the mountain pine beetle-infested lodgepole pine trees.

La thèse est consacrée à l'étude de deux procédés hybrides importants du point de vue de l'intensification des procédés : la distillation extractive discontinue (DED) et la distillation réactive discontinue (DRD). La faisabilité de la séparation d'un mélange azéotropique à maximum a été montrée en utilisant un solvant intermédiaire dans une configuration traditionnelle de la DED. Une nouvelle configuration avec une alimentation inversée est présentée et sa plus grande efficacité a été prouvée. Une méthode de faisabilité générale est développée dans la deuxième partie de la thèse pour la DRD. La déduction des équations du modèle et un algorithme pour les résoudre sont présentés. La nouvelle méthodologie a été validée sur deux systèmes réactifs. Les résultats ont été validés par des simulations dans les deux cas et expérimentalement pour la DED.

碩士
國立屏東科技大學
土木工程系碩士班
93
To be able to utilize the interconnectivity between surface water and groundwater near a river an experiment was conducted by extracting groundwater from the river bank, as a reliable water resource, with as objective to meet the needs of water supply in the future. The study targeted the major river bed and wetland park in the upper reaches of the grade control structure of Caogong Canal, on the left bank of the Kaoping River, by carrying out a pumping test using a newly installed pumping well to obtain hydrogeological parameters. The K value obtained from a quantitative water test was 26.3 m/d, and that derived from the backwater test was 29.7 m/d. Both values are almost equal to that of 26.26 m/d found for the groundwater monitoring network at the Chishan Station, near the Pingtung Plain, and can therefore serve as a reference for future groundwater model simulations. In addition, according to the study's observations of nearly one year in the Kaoping River itself, the groundwater flux was not changed into outflow to the river as a result of constructing the Kaoping River Dashu Weir, the grade control structure of Caogong Canal, and the grade control structure at Kaoping Bridge. Pumping drawdown was simulated, calculated and compared in this study by using Huisman’s method, Bear’s imaging method, and a one-dimensional groundwater model. The results show that the smallest drawdown is derived when using the imaging method.