This study investigated the commissioning and maintenance of a Pennells two-tank bioreactor system with specific reference to its application in rural areas of KwaZulu- Natal, South Africa to treat sewage and generate biogas. The septic tank configuration was installed in a community which lacked electricity and domestic waste disposal. An artificial wetland was constructed at the outlet of the system to facilitate further treatment. Inefficient operation and maintenance of the system occurred due to various social/community-related problems which are typical of a field- and community-based project of this nature in a rural region of a Third World African country. These problems affected both maintenance and digester performance. The Pennells system was characterized by incomplete anaerobiosis which limited methanogenesis. Despite this, and attendant problems of low temperatures and elevated pH values, COD removal resulted. Laboratory-scale batch cultures, in conjunction with fluorescence and scanning electron microscopy, were used to identify a suitable anaerobic digester sludge for inoculation purposes. Perturbation experiments with locally used detergents and toxic compounds demonstrated the inimical effects of these agents. In contrast, low concentrations of penicillin and tetracycline promoted methanogenesis. Further analysis with light, fluorescence and scanning electron microscopy identified the acidogens as the predominant bacterial species, whilst fluorescence microscopy confirmed the absence of methanogens in the bioreactor. / Thesis (M.Sc)-University of Natal, Pietermaritzburg, 1997.

A large-scale experimental, state of the art storage facility was constructed on the Macdonald Campus of McGill University. This storage facility will serve as a tool to further investigate many of the laboratory experiments performed in agricultural and food science topics, by providing a representation of actual storage facilities in use in the industry today. The storage facility was fully instrumented to provide valuable data of the stored commodity and it's environment. A custom control software was developed with a user friendly graphical interface. This fully automated software allows data acquisition and control of temperature and relative humidity of the experimental storage facility. / Experiments were performed and the control software provided an adequate temperature and relative humidity control. The controller was based on a conventional PID or proportional, integral and derivative controller. To further improve the control of the storage facility, a novel multivariable PID controller was developed using enthalpy as the process variable, which encompasses both temperature and relative humidity. The novel controller was tested using a mathematical model developed. Simulations were performed comparing the performance of the novel multivariable controller to two other conventional controllers. The results demonstrate that the novel multivariable PID controller is capable of controlling temperature and relative humidity better than the other two conventional control techniques.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Machine learning techniques have been around for a few decades now and are being established as a pre-dominant feature in most control applications. Elevators create a unique control application where traffic flow is controlled and directed according to certain control philosophies. Machine learning techniques can be implemented to predict and control every possible traffic flow scenario and deliver the best possible solution. Various techniques will be implemented in the elevator application in an attempt to establish a degree of artificial intelligence in the decision making process and to be able to have increased interaction with the passengers at all times. The primary objective for this thesis is to investigate the potential of machine learning solutions and the relevancy of such technologies in elevator control applications. The aim is to establish how the research field of machine learning, specifically neural network science, can be successfully utilised with the goal of creating an artificial intelligent (AI) controller. The AI controller is to adapt to its existing state and change its control parameters as required without the intervention of the user. The secondary objective for this thesis is to develop an elevator model that represents every aspect of the real-world application. The purpose of the model is to improve the accuracy of existing theoretical and simulated models, by modulating previously unknown and complex variables and constraints. The aim is to create a complete and fully functional testing platform for developing new elevator control philosophies and testing new elevator control mechanisms. To achieve these objectives, the main focus is directed to how waiting time, probability theory and power consumption predictions can be optimally utilised by means of machine learning solutions. The theoretical background is provided for these concepts and how each subject can potentially influence the decision making process. The reason why this approach has been difficult to implement in the past, is possibly mainly due to the lack of adequate representation for these concepts in an online environment without the continuous feedback from an Expert System. As a result of this thesis, the respective online models for each of these concepts were successfully developed in order to deal with the identified shortcomings. The developed online models for projected waiting times, probability networks and power consumption feedback were then combined to form a new Intelligent Elevator Controller (IEC) structure as opposed to the Expert System approach, mostly used in present computer based elevator controllers. / AFRIKAANSE OPSOMMING: Masjienleertegnieke bestaan al vir 'n paar dekades en is 'n oorwegende kenmerk in hedendaagse beheertoestelle. Hysbakke skep 'n unieke beheertoepassing, waar verkeersvloei beheer en gerig kan word volgens sekere beheer loso e. Masjienleertegnieke kan geïmplementeer word om elke moontlike verkeersvloei situasie te voorspel en te beheer en die beste moontlike oplossing te lewer. Verskeie tegnieke sal in die tesis ondersoek word in 'n poging om 'n mate van kunsmatige intelligensie in die besluitneming proses te skep asook verhoogte interaksie met die passasiers te alle tye. Die prim^ere doel van hierdie tesis is om die potensiaal van 'n masjienleer oplossing en die toepaslikheid van dit in hysbakbeheertoepassings te ondersoek. Die doel is om vas te stel hoe die navorsing in die veld van die masjienleer, spesi ek in neurale netwerk wetenskappe, suksesvol aangewend kan word met die doel om 'n kunsmatige intelligente beheerder te skep. Die kunsmatige intelligente beheerder moet kan aanpas by sy onmidelike omgewing en sy beheer parameters moet kan verander soos nodig sonder die ingryping van die gebruiker. Die sekond^ere doelwit vir hierdie tesis is om 'n hysbakmodel, wat elke aspek van die werklike w^ereld verteenwoordig, te ontwikkel. Die doel van die model is om die akkuraatheid van die bestaande teoretiese en gesimuleerde modelle te verbeter deur voorheen onbekende en komplekse veranderlikes en beperkings in ag te neem. Die doel is om 'n funksionele toetsplatform te skep vir die ontwikkeling van nuwe hysbakbeheer loso e en vir die toets van nuwe hysbakbeheermeganismes. Om hierdie doelwitte te bereik, is die hoo okus gerig om wagtyd, waarskynlikheidsteorie en kragverbruik voorspellings optimaal te gebruik deur middel van die masjienleer oplossings. Die teoretiese agtergrond is voorsien vir hierdie konsepte en hoe elke konsep potensieel die besluitneming kan beïnvloed. Die rede waarom hierdie benadering moeilik was om te implementeer tot hede, is moontlik te wyte aan die gebrek aan voldoende verteenwoordiging vir hierdie konsepte in 'n aanlynomgewing sonder die voortdurende terugvoer van 'n Deskundige Stelsel. As gevolg van hierdie tesis word die onderskeie aanlynmodelle vir elk van hierdie konsepte suksesvol ontwikkel om die geïdenti seerde tekortkominge te oorkom. Die ontwikkelde aanlynmodelle vir geprojekteerde wagtye, waarskynlikheidsnetwerke en kragverbruik terugvoer is dan gekombineer om 'n nuwe intelligente hysbakbeheerder struktuur te skep, in teenstelling met die Deskundige Stelsel benadering in die huidige rekenaar gebaseerde hysbakbeheerders.

Thesis (MPhil)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: With the emergence of Web 2.0 (social network platforms) some Knowledge Management theorists saw the potential for incorporating its collaborative and networking features in Knowledge Management Systems. However, the consensus is that harnessing Web 2.0 features for Knowledge Management is still in its infancy and according to some it seems that Web 2.0 success in the social sphere is hard to translate to the work context. The thesis argues that Web 2.0 primarily facilitates Personal Knowledge Management (PKM) and in this way indirectly contributes to Organisational Knowledge Management. Furthermore not all Web 2.0 features are equally useful in facilitating Personal Knowledge Management. The thesis identifies the group features of social network platforms as the prime locations for networking and learning. The thesis is theoretically based on Cheong and Tsui's PKM 2.0 model, in particular the Interpersonal Knowledge Transferring phase that in turn is based on Nonaka's SECI model of knowledge conversion. The thesis starts out with considering the distinction and relationship between Organisational Knowledge Management (OKM) and Personal Knowledge Management (PKM). Thereafter Cheong and Tsui's PKM 2.0 model is described as well as Nonaka's SECI model. The Web 2.0 phenomenon is introduced through a literature review of various studies on the usefulness of social network platforms and the group features are specifically highlighted. A survey is conducted among users of a particular Web 2.0 group feature, based on questions developed from the SECI and PKM 2.0 models. The thesis comes to the conclusion that the group features of Web 2.0 social network platforms are useful for Knowledge Management, because it is indeed a component of users' Personal Knowledge Management. / AFRIKAANSE OPSOMMING: Sekere Kennisbestuursteoretici het met die opkoms van Web 2.0 (sosiale netwerk-platforms) die moontlikheid waargeneem om die samewerks- en netwerk-funksionaliteit van Web 2.0 platforms met bestaande Kennisbestuurstelsels te integreer. Die konsensus is egter dat sulke pogings nog veel tekortskiet en sommige waarnemers meen dat dit baie moeilik sal wees om Web 2.0 se sukses in die sosiale sfeer in die werksplek in te span. Die tesis argumenteer dat Web 2.0 hoofsaaklik Persoonlike Kennisbestuur (PKB) fasiliteer en langs hierdie ompad 'n bydrae lewer tot Organisatoriese Kennisbestuur (OKB). Verder lewer alle funksionaliteite van Web 2.0 nie 'n bruikbare bydra tot Kennisbestuur nie, maar is dit hoofsaaklik die groepsfunksies wat bruikbaar is in terme van netwerking en leer. Die tesis is teoreties gewortel in Cheong en Tsui se PKB 2.0 model, veral die Interpersoonlike Kennisoordragsfase wat weer op Nonaka se SEKI model gebaseer is. Die tesis oorweeg aanvanklik die onderskeid en verhouding tussen Organisatoriese Kennisbestuur (OKB) en Persoonlike Kennisbestuur (PKB). Daarna word Cheong en Tsui se PKB 2.0 model en Nonaka se SEKI model bespreek. Die Web 2.0 fenomeen word beskryf aan die hand van 'n literatuurstudie van navorsing oor die bruikbaarheid van Web 2.0 platforms en die groepsfunksionaliteit word spesifiek belig. 'n Vraelys, gebaseer op die SEKI en PKB 2.0 modelle, is onder gebruikers van 'n spesifieke Web 2.0 groepsfunksie geadministreer. Die tesis kom tot die konklusie dat die groepsfunksies van Web 2.0 sosiale netwerk-platforms bruikbaar is vir Kennisbestuur, want dit is inderdaad 'n komponent van gebruikers se Persoonlike Kennisbestuur (PKB).

Made available in DSpace on 2014-11-10T11:09:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-05-29Bitstream added on 2014-11-10T11:58:01Z : No. of bitstreams: 1 000789630_20141229.pdf: 409322 bytes, checksum: ffbf7ab412d7ca57518c2014df4f7a52 (MD5) Bitstreams deleted on 2015-01-05T11:00:54Z: 000789630_20141229.pdf,Bitstream added on 2015-01-05T11:01:50Z : No. of bitstreams: 1 000789630.pdf: 2048959 bytes, checksum: 453ad5bd7d63b78e68c4bf76a6845403 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho visou dar tratamento tecnológico a extratos enzimáticos ricos em endoglucanases obtidos por cultivo em estado sólido (CES) do fungo termofílico Myceliophtora thermophila M77, através da secagem por spray-drying. A fim de garantir a estabilidade das enzimas durante um período de armazenamento, o extrato enzimático bruto (EEB) foi seco em spray-dryer sendo investigados os parâmetros operacionais e os adjuvantes de secagem para garantir a maior retenção da atividade enzimática após a secagem. Os ensaios foram divididos entre discriminação do adjuvante que proporcionasse maior proteção às enzimas, otimização das condições de secagem, armazenamento do EEB e dos pós secos, avaliação do efeito da secagem sobre as propriedades físico-químicas das endoglucanases e morfologia dos pós. Utilizou-se de planejamentos estatísticos para analisar os efeitos das variáveis temperatura de saída do ar de secagem, vazão de alimentação de solução, proporção entre o EEB e adjuvante, e teor de sólidos na formulação, sendo as respostas retenção de atividade enzimática e umidade dos pós. Nos ensaios de discriminação foi selecionado o adjuvante goma arábica. Em seguida, nos ensaios para otimização das condições de secagem, foi identificado menor vazão de alimentação e menores temperaturas de saída do ar de secagem para maiores retenções de atividade enzimática e maiores temperaturas e menores vazões para menores teores de umidade dos pós, o teor de sólidos revelou-se não significativo. O pó obtido nas condições mais favorável e menos favorável para a retenção da atividade enzimática foi armazenado à temperatura ambiente e sob refrigeração e a atividade enzimática determinada quinzenalmente. A análise estatística revelou não haver diferença na retenção da atividade enzimática após longos períodos para ambas as condições de secagem selecionadas e alternativas de armazenamento... / This work aimed to provide technological treatment to enzymatic extract rich in endoglucanase, obtained by solid state culture using the fungus Myceliophtora thermophila M77, through spray-drying. Operational parameters and adjuvants were varied in order to obtain stable enzymes with high activities during storage. The experiments were divided into adjuvant discrimination, optimization of the drying conditions, storage of the raw enzymatic extract (REE) and powders, evaluation of drying on the physical-chemical characteristics of the endoglucanase, and powder morphology. Statistical experimental designs were used to evaluate the effect of the variables exit air temperature, solution flow rate, proportion REE/adjuvant, and total solid content on the enzyme activity retention and powder moisture content. The adjuvant Arabic gum was selected from the discrimination assays. From the optimization experiments, it was determined that the lower flow rate and air exit temperature resulted in the highest enzyme activity retention, while low temperature and solution flow rate resulted in the lowest retention. The total solid concentration was not statistically significant. The powders produced in the Best and in the worst drying conditions were stored at room temperature and under refrigeration and the enzymatic activity was measured at 15 days intervals. The statistical analysis did not show any difference in the enzymatic activity retention after long periods of storage for both drying conditions and both storage alternatives. The influence of temperature and pH on the enzyme activity was also investigated before and after the drying process, and it was noticed that these physical-chemical properties were not affected by the adjuvants and by the drying process. The morphology of the powders, obtained using the inert gas adsorption method, indicated that the powder obtained under the worst drying condition presented specific superficial area twice ...

Made available in DSpace on 2014-12-02T11:16:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-11-29Bitstream added on 2014-12-02T11:21:22Z : No. of bitstreams: 1 000791747_20160107.pdf: 391327 bytes, checksum: 7bae48548e730d96c10d4d65576e4e26 (MD5) Bitstreams deleted on 2016-01-12T18:57:18Z: 000791747_20160107.pdf,. Added 1 bitstream(s) on 2016-01-12T18:58:35Z : No. of bitstreams: 1 000791747.pdf: 1679458 bytes, checksum: cbef661cf8e1e32aaff5b1b1acd034bc (MD5) / Devido à ampliação das aplicações industriais das celulases e hemicelulases, é crescente o interesse na produção destas enzimas por micro-organismos através de processos que promovam altos rendimentos a baixo custo. Assim, o cultivo de fungos filamentosos por fermentação em estado sólido (FES) utilizando-se resíduos lignocelulósicos como substratos tem sido frequentemente citado na literatura. Os fungos termofílicos tem se destacado neste sentido, por produzirem enzimas geralmente mais ativas e estáveis sob altas temperaturas, uma vantagem do ponto de vista das aplicações industriais. No presente trabalho, foram isolados 32 fungos termofílicos do ambiente a partir de amostras de silagem, compostagem e outros materiais orgânicos. Uma triagem inicial dos melhores produtores foi feita pelo cultivo dos isolados, por FES, em mistura de bagaço de cana-de-açúcar e farelo de trigo (1:1 p/p) como substratos, por 96h. A partir destes cultivos foram pré-selecionados 7 isolados, os quais foram então cultivados por FES em diferentes misturas de resíduos agro-industriais, por 96h, a fim de se avaliar a influência dos mesmos na produção das enzimas, buscando-se maiores rendimentos. Foram então selecionados para dar continuidade ao trabalho os isolados que mais se destacaram na produção das enzimas: Myceliophthora thermophila JCP 1-4 (endoglucanase, -glicosidase, xilanase e avicelase) e DABM 11/45 (-glicosidase, xilanase e avicelase). A influência do tempo de cultivo na produção das enzimas pelos dois isolados selecionados foi avaliada e as enzimas foram caracterizadas físico-quimicamente. O extrato enzimático produzido por M. thermophila, por FES, em mistura de bagaço de cana-de-açúcar e farelo de soja (1:1 p/p) foi utilizado para a sacarificação de bagaço de cana in natura e pré-tratado com ozônio. Foram ainda realizados ensaios de sacarificação com enzimas comerciais, para fins comparativos. Os bagaços in . / Due to the expansion of industrial applications of cellulases and hemicellulases, there is increasing interest in the production of these enzymes by micro-organisms through processes that promote high yields at low cost. Thus, the cultivation of filamentous fungi by solid state fermentation (SSF) using lignocellulose residues as substrates has been frequently cited in the literature. The thermophilic fungi has excelled in this regard, since they produce enzymes usually more active and stable under high temperatures, an advantage from the point of view of industrial applications. In this work, 32 thermophilic fungi were isolated from the environment, from samples of silage, composting and other organic materials. An initial screening of the best producers was made by cultivation of isolates, by SSF, in a mixture of sugar cane bagasse and wheat bran (1:1 w/w) as substrates, for 96h. From these cultivations 7 isolates were pre-selected, which were then cultured by SSF in different mixtures of agro-industrial residues, for 96h, in order to assess the influence of these substrates in enzymes production, seeking higher yields. Then, were selected to give continuity to the work the isolates that stood out in the production of enzymes: Myceliophthora thermophila JCP 1-4 (endoglucanase, -glucosidase, xylanase and avicelase) and DABM 11/45 (-glucosidase, xylanase and avicelase). The influence of the time on the enzymes production by the two selected isolates was assessed and the enzymes were characterized physico-chemically. The enzymatic extract produced by M. thermophila, by FES, in a mixture of sugar cane bagasse and soybean meal (1:1 w/w) was used for the saccharification of in natura and pre-treated with ozone sugarcane bagasse. Saccharification assays were also performed with commercial enzymes, for comparative purposes. The in natura and ozonized bagasse were characterized regarding the content of cellulose, hemicellulose and lignin ...

Neste trabalho, são descritos os detalhes da montagem de um sistema de cultivo microbiano em estado sólido, cujo elemento principal é um biorreator de tambor rotativo em escala de bancada, com casco em vidro refratário com aproximadamente 6,2 litros de volume. A montagem do equipamento exigiu estudos para a definição dos seguintes aspectos: geometria do reator; controle de frequência e período de agitação; umidificação, aquecimento e controle do fluxo do ar injetado no sistema; mistura do meio de cultivo; medição e controle da temperatura do meio; retirada de amostras. O sistema desenvolvido foi avaliado, tendo como processo fermentativo modelo o cultivo de Aspergillus niger T0005/007-2, microrganismo produtor de enzimas pectinolíticas. Os testes foram feitos em um meio contendo farelo de trigo como suporte sólido, avaliando-se a influência de três parâmetros principais agitação, massa de meio de cultivo e temperatura do meio sobre o crescimento celular e a produção de endo-poligalacturonase (PG) por A. niger. Três formas de agitação do meio sólido foram comparadas: sem agitação; agitação a 1 rpm por 5 minutos a cada duas horas; agitação a 1 rpm por 1 hora e 55 minutos a cada duas horas. A segunda forma de agitação levou ao melhor crescimento celular, 81 mg.g-1, e a atividade de endo-PG da ordem de 80 U.g-1, semelhante ao estimado com o sistema estático. Com a terceira forma de agitação, aparentemente houve dano ao micélio fúngico e, com isso, resultados inferiores foram alcançados. A avaliação do efeito da massa de meio de cultivo sobre o processo foi feita com cargas crescentes de meio que resultaram na ocupação de 30, 45 e 60 % do volume útil do reator. Quanto ao crescimento celular, o melhor resultado foi alcançado com a menor carga de meio, enquanto que a carga intermediária resultou no mais alto título enzimático final, 107,2 U.g-1. Nos experimentos sobre a influência da temperatura sobre o cultivo de A. niger, a maior atividade enzimática (80,6 U.g-1) foi obtida numa condição de trabalho que permitiu que a temperatura do meio atingisse valores da ordem de 45ºC. Com o meio mantido a 30ºC, a atividade enzimática máxima foi substancialmente mais baixa, 46,4 U.g-1. Nos testes realizados com o processo modelo, não se verificou uma clara influência positiva da agitação sobre a produção de endo-PG. Entretanto, a partir dos experimentos com temperatura controlada, é possível sugerir que a formação de endo-PG é favorecida por uma condição de estresse para o microrganismo, no caso representado por temperaturas do meio acima de 40ºC, visto que a temperatura ideal de crescimento de A. niger encontra-se na faixa de 28 a 34ºC. Este resultado, que discorda do que é genericamente descrito na literatura especializada sobre cultivos em estado sólido, é um exemplo da importância de dispor-se de um biorreator de tambor rotativo de pequena escala como equipamento básico para a realização de estudos fundamentais a respeito deste tipo de processo. Adicionalmente, o fato de o corpo do reator ser construído em vidro permite a visualização do espaço interno do tambor rotativo e observar o efeito da agitação sobre o meio de cultivo. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-02T17:41:21Z No. of bitstreams: 1 Dissertacao Tomas Augusto Polidoro.pdf: 1493269 bytes, checksum: 0ed8a1384e54fe0a00f47be237707cbf (MD5) / Made available in DSpace on 2014-06-02T17:41:21Z (GMT). No. of bitstreams: 1 Dissertacao Tomas Augusto Polidoro.pdf: 1493269 bytes, checksum: 0ed8a1384e54fe0a00f47be237707cbf (MD5) / In this work, details on the assembling of a solid state cultivation system, whose main component is a bench scale rotating-drum bioreactor, are described. The bioreactor was built in refractory glass and has an approximate volume of 6.2 liters. To assemble the equipment, the following aspects have been studied: geometry of the bioreactor; control of frequency and period of agitation; moistening, warming and controlling of the inlet air flux; mixing of cultivation medium; determination and control of medium temperature; sample withdrawn. The developed system was evaluated, being the cultivation of the pectinolytic enzymeproducing microorganism Aspergillus niger T0005/007-2 used as the model process. The fermentative tests were carried out in a medium containing wheat-straw as solid support and were used to evaluate the effects of three main parameters agitation, mass of cultivation medium and medium temperature on the cell growth and the production of endopolygalacturonase (endo-PG) by A. niger. For agitation of the solid medium, three modes were compared: no agitation; agitation of 1 rpm for 5 minutes each 2 hours; agitation for 1 hour and 55 minutes, each 2 hours. The second mode of agitation led to the best cell growth, 81 mg.g-1, and to endo-PG activity of approximately 80 U.g-1, similar to that obtained with the static system. With the third mode of agitation occurred, apparently, some damage to fungus mycelium and inferior results were achieved. The evaluation of the mass of cultivation medium on the process was done by loading the reactor with masses that result in the occupation of 30, 45 and 60% of the working volume of the bioreactor. With respect to the cell growth, the best result was attained with the smallest load of medium, whereas the intermediate load resulted in the highest endo-PG activity, 107.2 U.g-1. In the experiments on the influence of the temperature on the cultivation of A. niger, the largest endo-PG activity (80.6 U.g-1) was obtained in a process condition that allowed that the temperature reached values close to 45ºC. When the medium temperature was controlled at 30ºC, the endo-PG activity was substantially lower, 46.4 U.g-1. In the tests with the model process, no clearly positive influence of agitation on the production of endo-PG was observed. From the temperature-controlled experiments however, it is possible to suggest that endo-PG formation is favored by a stress condition for the microorganism, represented in this case by medium temperatures over 40ºC, since the optimal temperatures for A. niger growth is found in the range of 28 to 34ºC. This result disagrees from what is generically described in the specialized literature for the solid state cultivations, being this fact an example of the importance of having a small-scale rotating-drum bioreactor as a basic equipment for fundamental studies on that type of fermentative process. Additionally, the fact of the reactor body being built on glass allows the inspection of the internal space of the rotating drum and to observe the effects of agitation on the cultivation medium.

Orientador: João Cláudio Thoméo / Banca: Gustavo Orlando Bonilla Rodriguez / Banca: Izabela Dutra Alvin / Resumo: Este trabalho visou dar tratamento tecnológico a extratos enzimáticos ricos em endoglucanases obtidos por cultivo em estado sólido (CES) do fungo termofílico Myceliophtora thermophila M77, através da secagem por spray-drying. A fim de garantir a estabilidade das enzimas durante um período de armazenamento, o extrato enzimático bruto (EEB) foi seco em spray-dryer sendo investigados os parâmetros operacionais e os adjuvantes de secagem para garantir a maior retenção da atividade enzimática após a secagem. Os ensaios foram divididos entre discriminação do adjuvante que proporcionasse maior proteção às enzimas, otimização das condições de secagem, armazenamento do EEB e dos pós secos, avaliação do efeito da secagem sobre as propriedades físico-químicas das endoglucanases e morfologia dos pós. Utilizou-se de planejamentos estatísticos para analisar os efeitos das variáveis temperatura de saída do ar de secagem, vazão de alimentação de solução, proporção entre o EEB e adjuvante, e teor de sólidos na formulação, sendo as respostas retenção de atividade enzimática e umidade dos pós. Nos ensaios de discriminação foi selecionado o adjuvante goma arábica. Em seguida, nos ensaios para otimização das condições de secagem, foi identificado menor vazão de alimentação e menores temperaturas de saída do ar de secagem para maiores retenções de atividade enzimática e maiores temperaturas e menores vazões para menores teores de umidade dos pós, o teor de sólidos revelou-se não significativo. O pó obtido nas condições mais favorável e menos favorável para a retenção da atividade enzimática foi armazenado à temperatura ambiente e sob refrigeração e a atividade enzimática determinada quinzenalmente. A análise estatística revelou não haver diferença na retenção da atividade enzimática após longos períodos para ambas as condições de secagem selecionadas e alternativas de armazenamento... / Abstract: This work aimed to provide technological treatment to enzymatic extract rich in endoglucanase, obtained by solid state culture using the fungus Myceliophtora thermophila M77, through spray-drying. Operational parameters and adjuvants were varied in order to obtain stable enzymes with high activities during storage. The experiments were divided into adjuvant discrimination, optimization of the drying conditions, storage of the raw enzymatic extract (REE) and powders, evaluation of drying on the physical-chemical characteristics of the endoglucanase, and powder morphology. Statistical experimental designs were used to evaluate the effect of the variables exit air temperature, solution flow rate, proportion REE/adjuvant, and total solid content on the enzyme activity retention and powder moisture content. The adjuvant Arabic gum was selected from the discrimination assays. From the optimization experiments, it was determined that the lower flow rate and air exit temperature resulted in the highest enzyme activity retention, while low temperature and solution flow rate resulted in the lowest retention. The total solid concentration was not statistically significant. The powders produced in the Best and in the worst drying conditions were stored at room temperature and under refrigeration and the enzymatic activity was measured at 15 days intervals. The statistical analysis did not show any difference in the enzymatic activity retention after long periods of storage for both drying conditions and both storage alternatives. The influence of temperature and pH on the enzyme activity was also investigated before and after the drying process, and it was noticed that these physical-chemical properties were not affected by the adjuvants and by the drying process. The morphology of the powders, obtained using the inert gas adsorption method, indicated that the powder obtained under the worst drying condition presented specific superficial area twice ... / Mestre

Dissertation submitted in fulfilment of the requirements for the Masters Degree in Technology: Chemical Engineering in the Department of Chemical Engineering of Cape Peninsula University ofTechnology, 2005 / The emulsion used for this study is a new thermodynamically unstable multi-component waterin- oil (w/o) explosive type with an internal phase ratio of approximately 94%, i.e. far beyond the close packing limit of spherical droplets of 74%. Economic considerations and the ongoing need for continuous drilling, loading and blasting in the mining industry, has made long-distance pipeline transportation of these emulsion explosive systems a viable economic option. Presently, rheological characterization of emulsion explosives is well documented (Bampfield & Cooper, 1988, Utracki, 1980). However, very little or none has been done for this system, pertaining to the use of rheometry for prediction of pumping characteristics of these systems in long-distance pipeline transport. This Master's dissertation is devoted to develop rheological methods of testing, characterization and correlation in order to develop a basis for predicting the pumping characteristics of highly concentrated w/o emulsion explosives from rheometry. The literature and theory pertinent to the pipeline flow of high internal phase ratio emulsion explosives are presented, as well as the fundamentals of both concentric cylinder rheometry and pipe viscometry. The most relevant is the work of Bampfield and Cooper (1988), Utracki (1980) and Pal (1990). Two experimental test facilities were used for data collection. Pipeline experiments were done using an experimental test facility at African Explosives Limited (AEL), and rheometry was conducted at the Rheology Laboratory of the Cape Peninsula University of Technology Flow Process Research Centre. The AEL experimental test facility consisted of a four-stage Orbit progressive cavity pump, two fluid reservoirs, (a mixing tank and a discharge reservoir), five 45m HOPE (high density polyethylene) pipes of internal diameters of 35.9 mm, 48.1 mm, 55.9 mm, 65.9 mm and 77.6 mm pipes. The test work was done over a wide range of laminar flow rates ranging from 3 kg.min-I to 53 kg.min-I . Rheometry was done using a PaarPhysica MCR300 rheometer, and only standard rotational tests (i.e. flow curve) at 30 °c in controlled rate mode were done. Rheological characterisation was done using three rheological models, i.e. the Herschel-Bulkley, the Power Law and the Simplified Cross models. The coefficients obtained from these models were then used to predict pumping characteristics. The performances of these models were then evaluated by comparing the pipeline flow prediction to the actual pipeline data obtained from pipeline test experiments. It was found that the flow behaviour depicted by this explosive emulsion system was strongly non-Newtonian, and was characterized by two distinct regions of deformation behaviour, a lower Newtonian region of deformation behaviour in the shear rate region lower than 0.001 S-I and a strong shear thinning region in the shear rate range greater than 0.001 S-l. For all the models used for this study, it was evident that rheometry predicts the pumping characteristics of this high internal phase ratio emulsion reasonably well, irrespective of the choice of the model used for the predictions. It was also seen that the major difference between these models was in the lower shear rate domain. However, the Simplified Cross model was preferred over the other two models, since its parameter (the zero shear viscosity denoted by 110) can in general be correlated to the structure of the emulsion systems (i.e. mean droplet size, bulk modulus, etc.). Thus, structural changes induced by shearing (either inside the pump or when flowing inside a pipe) can be detected from changes in the value of the 110. The above statement implies that Tlo can be used as a quality control measure. Different pumping speeds were found to cause different degrees of shear-induced structural changes which were manifested by two opposing processes. These two opposing processes were the simultaneous coalescence and flocculation of droplets encountered at low rates of shear, and the simultaneous refinement and deflocculation of droplets encountered at high rates of shear. These two droplet phenomena were associated with a decrease or an increase in viscous effects, leading to both lower and higher viscous stresses and pumping pressures during pump start-up respectively.

Orientador: Daniela Alonso Bocchini Martins / Coorientador: Eleni Gomes / Banca: Luis Henrique Souza Guimarães / Banca: João Cláudio Thoméo / Resumo: Devido à ampliação das aplicações industriais das celulases e hemicelulases, é crescente o interesse na produção destas enzimas por micro-organismos através de processos que promovam altos rendimentos a baixo custo. Assim, o cultivo de fungos filamentosos por fermentação em estado sólido (FES) utilizando-se resíduos lignocelulósicos como substratos tem sido frequentemente citado na literatura. Os fungos termofílicos tem se destacado neste sentido, por produzirem enzimas geralmente mais ativas e estáveis sob altas temperaturas, uma vantagem do ponto de vista das aplicações industriais. No presente trabalho, foram isolados 32 fungos termofílicos do ambiente a partir de amostras de silagem, compostagem e outros materiais orgânicos. Uma triagem inicial dos melhores produtores foi feita pelo cultivo dos isolados, por FES, em mistura de bagaço de cana-de-açúcar e farelo de trigo (1:1 p/p) como substratos, por 96h. A partir destes cultivos foram pré-selecionados 7 isolados, os quais foram então cultivados por FES em diferentes misturas de resíduos agro-industriais, por 96h, a fim de se avaliar a influência dos mesmos na produção das enzimas, buscando-se maiores rendimentos. Foram então selecionados para dar continuidade ao trabalho os isolados que mais se destacaram na produção das enzimas: Myceliophthora thermophila JCP 1-4 (endoglucanase, -glicosidase, xilanase e avicelase) e DABM 11/45 (-glicosidase, xilanase e avicelase). A influência do tempo de cultivo na produção das enzimas pelos dois isolados selecionados foi avaliada e as enzimas foram caracterizadas físico-quimicamente. O extrato enzimático produzido por M. thermophila, por FES, em mistura de bagaço de cana-de-açúcar e farelo de soja (1:1 p/p) foi utilizado para a sacarificação de bagaço de cana in natura e pré-tratado glicerol e explosão à vapor. Os bagaços in natura e pré-tratados foram... / Abstract: Due to the expansion of industrial applications of cellulases and hemicellulases, there is increasing interest in the production of these enzymes by micro-organisms through processes that promote high yields at low cost. Thus, the cultivation of filamentous fungi by solid state fermentation (SSF) using lignocellulose residues as substrates has been frequently cited in the literature. The thermophilic fungi has excelled in this regard, since they produce enzymes usually more active and stable under high temperatures, an advantage from the point of view of industrial applications. In this work, 32 thermophilic fungi were isolated from the environment, from samples of silage, composting and other organic materials. An initial screening of the best producers was made by cultivation of isolates, by SSF, in a mixture of sugar cane bagasse and wheat bran (1:1 w/w) as substrates, for 96h. From these cultivations 7 isolates were pre-selected, which were then cultured by SSF in different mixtures of agro-industrial residues, for 96h, in order to assess the influence of these substrates in enzymes production, seeking higher yields. Then, were selected to give continuity to the work the isolates that stood out in the production of enzymes: Myceliophthora thermophila JCP 1-4 (endoglucanase, -glucosidase, xylanase and avicelase) and DABM 11/45 (-glucosidase, xylanase and avicelase). The influence of the time on the enzymes production by the two selected isolates was assessed and the enzymes were characterized physico-chemically. The enzymatic extract produced by M. thermophila, by FES, in a mixture of sugar cane bagasse and soybean meal (1:1 w/w) was used for the saccharification of in natura and pre-treated glycerol and steam exploded sugarcane bagasse. The in natura and pre-treated bagasse were characterized regarding the content of cellulose, hemicellulose and lignin. The enzymatic extract produced by newly isolated fungus Myceliophtora... / Mestre