Thesis (M.F.A.)--Rochester Institute of Technology, 1977. / Typescript. Includes bibliographical references (leaves 47-48).

Thesis (Ph.D) - University of Queensland, 2007. / Includes bibliography.

Thesis (M.S.)--Ohio State University, 1986. / Includes bibliographical references (leaf 149). Available online via OhioLINK's ETD Center

Universiẗat, Diss., 2003--Bonn.

ROCHA, Francisca de Oliveira. Secagem de polpa de manga (Mangifera indica, L.) cv. Palmer em spray-dryer: condições de secagem e estabilidade. 2017. 158 f. Dissertação (Mestrado em Ciência e Tecnologia de Alimentos)-Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Paulo Alencar (ppgcta@ufc.br) on 2017-07-03T18:51:36Z No. of bitstreams: 1 2017_dis_forocha.pdf: 3160710 bytes, checksum: 13fe9efd905ce8c88fd5ee70f29e16af (MD5) / Approved for entry into archive by Anderson Silva Pereira (anderson.pereiraaa@gmail.com) on 2017-07-04T20:13:42Z (GMT) No. of bitstreams: 1 2017_dis_forocha.pdf: 3160710 bytes, checksum: 13fe9efd905ce8c88fd5ee70f29e16af (MD5) / Made available in DSpace on 2017-07-04T20:13:42Z (GMT). No. of bitstreams: 1 2017_dis_forocha.pdf: 3160710 bytes, checksum: 13fe9efd905ce8c88fd5ee70f29e16af (MD5) Previous issue date: 2017 / The mango is a typically tropical fruit that has fallen in the taste of the Brazilian consumer. The Palmer variety is well accepted in the intern market because it has large, aromatic fruits and no fiber. The objective of this research was to obtain powder of mango pulp cv. Palmer through spray-dryer dehydration, as well as perform the study of drying conditions, quality parameters and product stability. For this, the pulp characterization was carried out, followed by the analysis of the influence of the maltodextrin concentration (%) and drying air temperature (°C) on the humidity (%), hygroscopicity, yield (%) and color (L *, a *, b *), through an experimental planning (DCCE). Physical, physical-chemical and morphological characterization were performed in the powder. The adsorption isotherms were determined at temperatures of 25, 35 and 45ºC. The stability of the powder was also evaluated for a period of 90 days under four storage conditions: laminated packaging with and without vacuum, and polyethylene with and without vacuum. The results revealed that the physico-chemical parameters of fresh pulp are in accordance with the legislation for fruit pulp except for acidity, the best drying conditions for mango pulp cv. Palmer and with addition of 30% dehydrated maltodextrin at a temperature of 150 °C. In the mango powder with 30% maltodextrin dehydrated at 150 ° C, there was an increase of ºBrix, of the total and reducing sugars, as well as a reduction in the content of ascorbic acid, carotenoids, moisture and water activity. The increased concentration of the adjuvant maltodextrin provided powders with lower wall friction angle, greater ease of flow, higher apparent densities, larger particles and more dispersed with each other. The GAB model was the one that better adjusted the experimental data of the isotherms of the mango powders with 10, 20 and 30% of maltodextrin at temperatures of 25, 35 and 45ºC. The stability study showed that vacuum-laminated packaging was more efficient against moisture gain, offering a greater barrier to water vapor and greater color retention. It was concluded that maltodextrin concentration influenced the physical, physical-chemical and morphological characteristics of mango powder, the spray-dryer dehydration process resulted in the loss of nutrients such as ascorbic acid and carotenoids, mango powder remained well during the 90 days of stability, with the laminated vacuum packaging being the most recommended for storage. / A manga é uma fruta tipicamente tropical que caiu no gosto do consumidor brasileiro. A variedade Palmer, é bem aceita no mercado interno, por apresentar frutos grandes, aromáticos e ausência de fibras. O objetivo desta pesquisa foi a obtenção do pó da polpa de manga cv. Palmer através da desidratação em spray-dryer, bem como realizar o estudo das condições de secagem, parâmetros de qualidade e estabilidade do produto. Para isso, realizou-se a caracterização da polpa, seguida da análise da influência da concentração de maltodextrina (%) e da temperatura do ar de secagem (ºC) sobre a umidade (%), higroscopicidade, rendimento (%) e cor (L*, a*, b*), através de um planejamento experimental (DCCE). No pó foi realizada caracterização física, físico-química e morfológica. Determinou-se as isotermas de adsorção nas temperaturas de 25, 35 e 45°C. Também avaliou-se a estabilidade do pó por um período de 90 dias, em quatro condições de armazenamento: embalagem laminada com e sem vácuo, e de polietileno com e sem vácuo. Os resultados revelaram que os parâmetros físico-químicos da polpa in natura estão de acordo com a legislação para polpa de frutas com exceção para acidez, as melhores condições de secagem para polpa de manga cv. Palmer e com adição de 30% de maltodextrina desidratado a uma temperatura de 150ºC. No pó de manga com 30% de maltodextrina desidratado a 150°C, verificou-se aumento do ºBrix, dos açúcares totais e redutores, bem como uma redução no conteúdo de ácido ascórbico, carotenoides, umidade e atividade de água. O aumento da concentração do adjuvante maltodextrina propiciou pós com menor ângulo de fricção da parede, maior facilidade de escoamento, maiores densidades aparentes, partículas maiores e mais dispersas entre si. O modelo de GAB foi o que melhor ajustou os dados experimentais das isotermas dos pós de manga com 10, 20 e 30% de maltodextrina nas temperaturas de 25, 35 e 45ºC. O estudo da estabilidade mostrou que a embalagem laminada a vácuo foi mais eficiente contra o ganho de umidade, ofertando maior barreira ao vapor de água e maior retenção da cor. Concluiu-se que concentração de maltodextrina influenciou nas características físicas, físico-químicas e morfológicas do pó de manga, o processo de desidratação em spray-dryer resultou na perda de nutrientes como ácido ascórbico e carotenoides, o pó de manga conservou-se bem durante os 90 dias da estabilidade, sendo a embalagem laminada a vácuo a mais recomendada para seu armazenamento.

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Orientador: Adilma Regina Pippa Scamparini / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T14:50:51Z (GMT). No. of bitstreams: 1 Boza_YolandaEugeniaAlamoGabrine_D.pdf: 25908915 bytes, checksum: b42e98d535b8f68469cf340abb3e0f01 (MD5) Previous issue date: 2003 / Resumo: A escolha adequada do material de parede é um dos fatores determin antes no grau de viabilidade e na manutenção da atividade fermentativa do inóculo encapsulado. Maltodextrina, glicose, amido modificado e goma arábica foram testadas como encapsulantes. Beijerínckíaencapsulada em maltodextrina, reidratada e inoculada em meio de fermentação previamente esterilizado, após um período de estocagem de dois meses, apresentou maior estabilidade da atividade fermentativa. A sobrevivencia e a atividade fermentativa das células de Beijerínckía encapsulada em maltodextrina foram tes tadas sob várias condições do spray-drier e durante posterior período de estocagem. A viabilidade bacteriana para todas condições testadas apresentou declinio pórem quando se utilizou menores temperatura de saída no spray -drier e teor de sólidos na suspen são obteve-se maior grau de sobrevivência. Para verificar a influência da encapsulação em maltodextrina sobre a produção de biopolímero comparou -se a atividade fermentativa das células de Beijerínckía encapsulada e não encapsulada. A partir das característ icas reológicas e químicas dos biopolímeros produzidos e da cinética fermentativa dos inóculos concluiuise que encapsulaçao de Beijerínckía influe no crescimento celular e na produção de biopolímero. / Abstract: An adequate choice of the wall (coating) material is one of the factors, which will determine the degree of cell survival and the maintenance of fermentative activity in the encapsulated inoculum. Malt dextrin, dehydrated glucose syrups, modified starch and acacia (gum Arabic) were used as wall ma terials. The results showed that spray dried Beijerinckia encapsulated in malt dextrin, stored for two months and inoculated into sterile must after re -hydration, presented the greatest stability related to fermentative activity and percent viability durin 9 spray drying and storage period. The survival and fermentative activity of Beijerinckia sp cultures encapsulated in malt dextrin by spray drying were determined under various conditions of spray drying and during the subsequent storage period of the products. The survival of Beijerinckia sp was greater with lower outlet air temperatures and with lower solids contents in the feed suspension during spray drying. Increasing either the spray dryer outlet air temperature or the feed solids content resulted in a decrease in the moisture content of the spray dried powders. A gradual decrease in viability was observed during storage for all treatments, although there was a relatively greater retention of fermenting activity in the inoculae obtained with lower outlet air temperatures and lower solids contents in the feed suspension. Was to examine the effects of encapsulation in malt dextrin on the production of biopolymer, comparing encapsulated and non-encapsulated Beijerinckia cells. From the characterization of the biopolymers and study of the fermentation kinetics, it was shown that the encapsulation of Beijerinckia mainly influenced cell growth and biopolymer production. / Doutorado / Doutor em Ciência de Alimentos

I visualized the flash-boiling atomization of liquid jets released into a low pressure environment at frame rates of up to five million frames per second. Such a high temporal resolution allowed us to observe for the first time the bubble expansion mechanism that atomizes the jet. To visualize the dynamics in detail, I focused closely to the outflow of the nozzle using a long distance microscope objective. I documented an abrupt transition from a laminar to a fully external flashing jet by systematically reducing the ambient pressure. I performed experiments with different volatile liquids and using nozzles with different inner diameters. The inner diameters of the nozzles varied from 30 to 480 µm. Perfluorohexane (PFnH) was our main working fluid, but also methanol, ethanol and 1-bromopropane were tested. Surprisingly, minimum intensity profiles revealed spray angles close to θs ~360°, meaning drops are ejected in all directions. Also, I measured speeds of bubble expansion up to 140 m/s. That is 45 times faster than the upper bound for inertial growth speed in complete vacuum from the Rayleigh-Plesset equation. I also calculated the trajectories of the ejected droplets as well as the drop speed distribution using particle tracking. I expect that our results bring new insight into the flash-boiling atomization mechanism.

A combination of experimental and computational methods is used to explore the microstructure and mechanical behavior of cold sprayed 6061 aluminum alloy and Ti-6Al-4V alloy and their substrate materials. A variety of microscopic methods are used for characterization of the microstructure. The indentation size effect and characteristic length of strain gradient plasticity for the substrate materials are determined. An FEA simulation describes the behavior of a worn Berkovich nanoindenter. Stress strain is studied experimentally in the substrate materials for future comparison with bulk cold-sprayed materials. Abaqus FEA models are used to simulate a single particle impact for a particle with an oxide layer using a linear Johnson-Cook plasticity model and a bilinear Johnson-Cook plasticity model. The implications of the results are discussed for cold spray processes.

Various sub models of a multi-zone phenomenological model are developed by incorporating Dec’s conceptual model and Siebers’ mixing limited theory and validated with experiments. The spray penetration model, liquid length model and lift-off length model are verified with experiment data. The ignition delay model is then validated with experiment data at different injection timings and loads. The air entrainment model is based on Siebers’ jet theory. Sub models for the premixed heat release rate and diffusion burn rate are also included. The overall phenomenological model is at first used to match the motoring pressure curve. The important sub models are well validated independently and the phenomenological model is useful in simulating diesel spray combustion. Future work is needed to integrate these sub models and to resolve existing issues in temperature profiles of the preparing zone and liquid zone.