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Master of Science / Department of Civil Engineering / Mustaque Hossain / A recent study at Kansas State University has shown that asphalt producers in Kansas are producing hot-mix asphalt (HMA) mixtures with lower asphalt contents than those in the job-mix formula. These drier mixtures are thought to be susceptible to moisture. This project evaluated the effect of asphalt content on rutting and moisture resistance of HMA. Two different mixtures and four varying asphalt contents, optimum and lower, were selected. Another large-size mixture with four varying asphalt contents was also studied. The Hamburg Wheel Tracking Device (HWTD)test (TEX-242-F) and the Kansas Standard Test-56 (KT-56), or modified Lottman test, were used to predict moisture damage and rutting potential of these mixes. All specimens tested were prepared with the Superpave gyratory compacter. Results of this study showed the drier mixtures performed better in rutting and were less susceptible to moisture.Asphalt content significantly affects the number of wheel passes in the HWTD test. The study also revealed a weak correlation between asphalt film thickness and performance test results. Thus, the effect of varying asphalt content is nonconclusive from a durability point of view. However, performance simulations using a theoretical model show that very dry mixes in asphalt pavements are likely to have shorter performance lives.

Made available in DSpace on 2014-12-17T15:01:30Z (GMT). No. of bitstreams: 1 FranciscoESJ_DISSERT.pdf: 2170552 bytes, checksum: 7eb8333582d6093d8dba28f6fb660743 (MD5) Previous issue date: 2012-08-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this research, the drying process of acerola waste was investigated by using a spouted bed drier. The process was conducted using high density polyethylene inert particles with the objective of producing an ascorbic acid-rich final product. The fruit waste was ground and used to prepare different water-maltodextrin suspensions. Initially, fluidynamical experiments were conducted in order to evaluate the feeding effect on the spouted bed drier fluidynamics behavior. The experimental planning 23 + 3 was used to investigate the effect of the following variables: solids concentration, drying air temperature, intermittence time, production efficiency, solids retention and product losses by elutriation of fine particles on drier walls. The effect of selected independent variables on the drier stability was also evaluated based on a parameter defined as the ratio between the feed suspension volume and the total inert particles volume. Finally, the powder quality was verified in experiments with fixed feed flow and varying air drying temperature, drying air velocity and intermittence time. It was observed that the suspension interferes in the spouted bed drier fluidynamics behavior, and higher air flow is necessary to stabilize the drier. The suspension also promotes the expansion of the spouted bed diameter, decreases the solid circulation and favors the air distribution at the flush area. All variables interfere in the spouted bed performance, and the solids concentration has a major effect on the material retention and losses. The intermittence time also has great effect on the stability and material retention. When it comes to production efficiency, the main effect observed was the drying air temperature. First order models were well adjusted to retention and losses data. The acerola powder presented ascorbic acid levels around 600 to 700 mg/100g. Similar moisture and ascorbic acid levels were obtained for powders obtained by spouted bed and spray drier. However, the powder production efficiency of the spray drier was lower when compared to spouted bed drier. When it comes to energetic analysis, the spray drier process was superior. The results obtained for spouted bed drier are promising and highly dependent on the operational parameters chosen, but in general, it is inferred that this drying process is adequate for paste and suspension drying / No presente trabalho estudou-se a secagem do res?duo industrial da acerola em secador de leito de jorro com part?culas inertes de polietileno de alta densidade, visando a obten??o de um produto seco com elevado valor agregado, principalmente no que concerne ao teor de ?cido asc?rbico. O res?duo foi triturado, preparando-se uma suspens?o com adi??o de ?gua e de maltodextrina em diferentes propor??es. Realizou-se inicialmente uma s?rie de experimentos fluidodin?micos para avaliar o efeito da alimenta??o da suspens?o sobre o comportamento fluidodin?mico do leito de jorro. Realizaram-se experimentos de secagem com base em um planejamento experimental 23 com 3 r?plicas no ponto central, onde foram avaliados os efeitos das vari?veis, teor de s?lidos, temperatura do ar de secagem e tempo de intermit?ncia sobre a umidade, efici?ncia de produ??o, reten??o de material no leito e perdas do produto em p? por elutria??o de finos e aderido ?s paredes do equipamento. Analisaram-se tamb?m os efeitos das vari?veis independentes sobre a estabilidade do secador representada a partir de um par?metro definido pela raz?o entre o volume de suspens?o alimentado ao leito e o volume total das part?culas inertes. Finalmente, com o objetivo de se verificar o desempenho do processo no que se refere ? qualidade do p?, realizaram-se na concentra??o de s?lidos mais favor?vel a obten??o do p?, experimentos de secagem fixando-se a vaz?o de alimenta??o e variando-se a temperatura e velocidade do ar de secagem e o tempo de intermit?ncia. De acordo com os resultados obtidos, a suspens?o interfere de forma importante no comportamento fluidodin?mico do leito, necessitando de maior vaz?o de ar para manter as condi??es de jorro. A suspens?o promove expans?o no di?metro do jorro, diminui a taxa de circula??o de s?lidos al?m de favorecer a distribui??o do ar na regi?o do jorro. Com respeito aos experimentos realizados conforme o planejamento experimental, todas as vari?veis interferiram no desempenho do secador, destacando-se o importante efeito do teor de s?lidos sobre a reten??o de material no leito e perdas, bem como o efeito da intermit?ncia sobre a estabilidade e reten??o de material no leito. Na efici?ncia de produ??o o efeito principal foi atribu?do ? temperatura do ar de secagem. Foram obtidos modelos de primeira ordem que se ajustaram bem aos dados de reten??o e perdas. Em rela??o aos experimentos finais, foram obtidos p?s com teor de ?cido asc?rbico na faixa de 600 a 700 mg/100g. Os resultados desses experimentos foram comparados com os resultados obtidos na secagem da mesma suspens?o, em spray dryer. A secagem no spray dryer forneceu um produto com teores de umidade e de ?cido asc?rbico compat?veis com o produzido no jorro, todavia na condi??o de opera??o testada a efici?ncia de produ??o de p? no spray foi inferior a do jorro. A compara??o dos dois processos mediante an?lise dos recursos energ?ticos favorece a opera??o de secagem no spray dryer. Todavia, os resultados obtidos no secador de leito de jorro s?o promissores, demonstrando que dependendo do ajuste das condi??es operacionais este secador se ad?qua bem a secagem de pastas e suspens?es

Orientador: Sandra Cristina dos Santos Rocha / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-06T13:17:18Z (GMT). No. of bitstreams: 1 Vieira_MelissaGurgelAdeodato_D.pdf: 15789035 bytes, checksum: a4310c5dbe44a9a8965201da94b3f2d8 (MD5) Previous issue date: 2006 / Resumo: o papel ainda desempenha um fator chave na cultura e na difusão da informação apesar dos grandes avanços tecnológicos. Embora seja produzido a partir de um recurso renovável, como é a madeira, existe tecnologia que permite a sua reutilização a partir de fibras recuperadas. A recic1agem do papel permite uma grande redução na quantidade de resíduos sólidos urbanos, evitando a utilização de recursos naturais tais como a madeira e a água, além de diminuir bastante o consumo energético na indústria papeleira. A produção da polpa de celulose é o grande consumidor de energia no processo de fabricação do papel, seguido da secagem do papel, que é o segundo processo neste tipo de indústria que mais consome energia. A secagem é um processo complexo, de grande importância tanto em termos energéticos como também na qualidade do produto final. Neste contexto, este trabalho teve como proposta analisar a secagem de polpa de celulose a partir de fibras recuperadas para a fabricação de papel cartão recic1ado. Para tanto, projetou-se um secador convectivo, em escala laboratorial, para a secagem da polpa de papel. Foram determinadas as curvas de secagem em função de diferentes condições operacionais e as isotermas de dessorção do papel pelo método dinâmico. Uma análise da qualidade do produto foi realizada para as diferentes condições, além da análise energética do processo. Paralelamente, fez-se um estudo comparativo entre a secagem natural ao ar livre (utilizada em pequenas produções) e a secagem .por convecção forçada no secador projetado. Complementando o estudo da secagem, analisou-se o encolhimento do papel durante a secagem, relacionando-o com as condições operacionais do processo, as características físicas e a qualidade do produto. O secador desenvolvido neste trabalho mostrou-se adequado para a secagem do papel recic1ado tipo cartão, apresentando uma eficiência energética compatível com a dos secadores utilizados na indútria papeleira (24,53%). Verificou-se que o aumento da temperatura e da velocidade do ar de secagem influencia positivamente no processo, reduzindo significativamente o tempo de secagem. No entanto, a qualidade do papel é inferior nas condições mais dráticas de secagem, obtendo-se um produto final com superfície menos uniforme e mais ressecada. No estudo de encolhimento durante a secagem, assim como na análise da qualidade da superfície (J / Abstract: Even though the great technological advances, the paper still carries out an important role in the culture and in the diffusion of information. Although it is produced by a renewable source, as the wood, technology allowing paper reuse is available. A selective pick up is necessary for the pulp processing from recovered fibers. The paper recycling allows a great reduction of the amount of urban solid residues, avoiding the use of natural sources as wood and water, besides decreasing a lot the energy consumption in the paper industry. The production of the cellulose pulp is the first great energy consumer in the process of paper production, followed by the paper drying process. The drying is a complex process, of great importance, not only in energy terms, but for the quality of the final product. In this context, this work had the objective to analyze the drying of cellulose pulp made from recovered fibers for the production of card type recycled paper. For this, a convective dryer was projected, in laboratorial scale, for the drying of the paper pulp. The drying curves as a function of different operating conditions were analyzed and the paper dessorption isotherms were determined by the dynamic method. An analysis of the product quality was accomplished for different conditions, as well as the process energy consumption evaluation. A comparative study between the natural drying (used in small productions) and the drying by forced convection was also effectuated. To complement the drying analysis, the shrinkage of the paper was evaluated during the drying and related to the operating conditions, physical characteristics and quality of the product. The dryer developed in this work showed to be appropriate for the drying of the recycled card type paper , presenting energy efficiency compatible with dryers used in paper industries (24,53%). It was verified that the increase of the temperature and velocity of the drying air influenced the process reducing the drying time. However, the quality of the paper is poor for severe operating conditions, leading to a less uniform final product, having a very dry surface. In the paper shrinkage study during drying, as well as in the analysis of the surface quality, similar results were gotten for the papers dried at 70 and 80°C. Significant modifications of structural properties and a low quality of the product were verified for the paper dried at 90°C, indicating a limit to the air temperature for the convective drying of the analyzed recycled papeI. The paper dried at 90°C suffered 15% of surface shrinkage and also 40% of linear and volume reduction during the falling rate drying phase. The paper dried under softer operating conditions (66°C; O,22m/s) presented characteristics similar to the paper naturally dried. Thus, a type card recycled paper can be producted with adequate quality using the convective drier, reducing significantly the necessary time for the drying af the paper sheet / Doutorado / Engenharia de Processos / Doutor em Engenharia Química

This thesis is devided into two parts. First part is a bibliographic search and speaks about maths modeling, simulations, a MATLAB Simulink programme, and a laundy process. Second part deals with a math model of an industrial laundry. In this part, there is a detailed descripton of the model and how the model was created.

Made available in DSpace on 2014-12-17T15:01:14Z (GMT). No. of bitstreams: 1 AndreiaSS.pdf: 675563 bytes, checksum: 8fb6ac6948a845dc7f3157989cb415a1 (MD5) Previous issue date: 2008-02-08 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work deals with the kinetics assay of Caj? (Spondias mombin L.) bagasse drying by an experimental design using a tray dryer. In order to add-value to this product a kinetic study has been carried out. A central composite experimental design has been carried out to evaluate the influence of the operational variables: input air temperature (55; 65 e 75?C); the drying air velocity (3.2; 4.6 e 6.0 m/s) and the fixed bed thickness (0.8; 1.2 e 1.6 cm) and as response variable the the moisture content (dry basis). The results showed that the diffusional Fick model fitted quite well the experimental data. The best condition found has been input air temperature of 75?C, drying air velocity of 6.0 m/s as well as fixed bed thickness of 0.8 cm. The experimental design assay showed that the main effects as well as the second ones were significant at 95% confindance level. The best operational condition according to statistical planning was 75 oC input air temperature, 6.0 m.s-1 drying air velocity and 0.8 cm fixed bed thickness. In this case, the equilibrium moisture content (1.3% dry basis) occured at 220 minutes / O presente trabalho teve como objetivo estudar a cin?tica de secagem do baga?o de caj? (mat?ria prima proveniente da ind?stria de processamento de polpa de frutas), em um secador convectivo de bandejas com leito fixo, em que se determinou o coeficiente de difusividade efetiva atrav?s do modelo difusional de Fick. Foi utilizado um planejamento fatorial composto central no qual foram avaliados os seguintes fatores: temperatura do ar de entrada no secador (55; 65 e 75?C); velocidade do ar de entrada (3,2; 4,6 e 6,0 m/s) e espessura da torta na bandeja (0,8; 1,2 e 1,6 cm). Os resultados mostraram que o modelo difusional de Fick descreve bem o processo de secagem e que a melhor condi??o foi com a temperatura de 75?C, velocidade do ar de secagem de 6,0 m/s e espessura da torta de 0,8 cm onde a difusividade efetiva calculada foi de 6,772 x 10-9 m2/s no tempo de 220 minutos. A an?lise do planejamento mostrou que todos os fatores e suas intera??es foram significativos, com n?vel de confian?a de 95%

Made available in DSpace on 2014-12-17T15:01:25Z (GMT). No. of bitstreams: 1 KatiaCB_DISSERT.pdf: 2815552 bytes, checksum: 5538a2db54454e17355a1ea7d2b7b8e5 (MD5) Previous issue date: 2011-02-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Fruits are rich sources of bioactive compounds, including phenolic compounds. Tropical fruit cultivation is an important productive segment in Brazilian Northeast. Its industrialization generates solid wastes as co-products, with potential environmental impact. Considering the recognized bioactive content of fruit and its derivatives, this research has the objective of investigating acerola (Malpighia glabra L.), caj?-umbu (Spondia ssp), jambolan (Syzygium cumini) and pitanga (Eugenia uniflora) dried wastes obtained by spouted bed drier. It was analyzed the physical-chemical composition, solubility and microphotographic aspect of these dried wastes. Besides this, it was also evaluated the bioactive content, antioxidant activity and inhibitory activity against aamylase and a-glycosidase enzymes of water and ethanol (70%, 80% e 100% v/v) extracts prepared from fruit dried wastes, as well as their possible correlations. The dried fruit wastes showed high phenolic (606.04 to 3074.6 mg GAE eq/100 g sample), anthocyanin (478.7 mg/100 g for jambolan) and ascorbic acid (2748.03 mg/100 g for acerola) contents, as well as high antioxidant DPPH activity (14.27 a 36.30 mg Trolox eq/g sample). The extracts exhibited moderate to high a-amylase inhibition (23.97% a 76.58%) and high α-glycosidase inhibition, which 99.32% peak was reached for ethanol 70% pitanga extracts. It was also observed great positive correlation between phenolic content and DPPH activity (0.97 for acerola), anthocyanin (0.95 for jambolan) and α- glycosidase inhibition (0.98 for acerola). The α-glycosidase inhibition also correlated well with the antioxidant activity for all fruit extracts. The results show that these dried fruit wastes are valuable material for further applications as functional ingredients / As frutas possuem importantes compostos bioativos, dentre eles os compostos fen?licos. O cultivo de frutas tropicais ? um importante segmento produtivo do Nordeste Brasileiro, mas sua industrializa??o gera res?duos s?lidos como c?-produtos da atividade, pass?veis de gerar impacto ambiental. Tendo em vista o reconhecido conte?do bioativo de frutas e seus c?-produtos, objetivou-se estudar o baga?o desidratado da acerola (Malpighia glabra L.), caj?-umbu (Spondia ssp), jambol?o (Syzygium cumini) e pitanga (Eugenia uniflora) obtidos em secador de leito de jorro. A partir disso, foi analisada a composi??o f?sico-qu?mica, solubilidade e aspecto microfotogr?fico dos baga?os secos. Al?m disso, foi avaliada a concentra??o de compostos bioativos, atividade antioxidante e atividade inibit?ria contra as enzimas α-amilase e α-glicosidase do extrato aquoso e extratos etan?licos (70%, 80% e 100% v/v) preparados a partir dos baga?os desidratados, bem como suas correla??es. Os p?s de fruta apresentaram elevado teor de compostos fen?licos (606,04 a 3074,6 mg GAE eq/100 g amostra), antocianinas (478,7 mg/100 g para jambol?o) e ?cido asc?rbico (2748,03 mg/100 g), bem como expressiva atividade antioxidante medida pelo m?todo DPPH (14,27 a 36,30 μg Trolox eq/g amostra). Os extratos foram capazes de expressar inibi??o da α-amilase de moderada a alta (23,97% a 76,58%) e expressiva inibi??o da α-glicosidase, cujo m?ximo de 99,32% foi alcan?ado pelos extratos etan?licos 70% da pitanga. Foi observada correla??o positiva entre o teor fen?lico e atividade antioxidante (0,97 para acerola), antocianinas (0,95 para jambol?o), inibi??o da α-amilase (0,99 para jambol?o) e inibi??o da α-glicosidase (0,93 para pitanga) e dessas duas ?ltimas com a atividade antioxidante para todos os frutos estudados. Os dados apresentados demonstram que os res?duos desidratados constituem valioso material de estudo para aplica??es como ingredientes funcionais