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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Microcompósitos, nanocompósitos e coberturas a base de materiais biodegradáveis obtidos a partir do Biri (Canna indica L.) / Microcomposites, nanocamposites and edible coatings based on biodegradable materials from Canna indica L

Andrade Mahecha, Margarita Maria, 1979- 05 April 2012 (has links)
Orientadores: Florencia Cecilia Menegalli, Delia Rita Tapia Blácido / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-20T05:16:21Z (GMT). No. of bitstreams: 1 AndradeMahecha_MargaritaMaria_D.pdf: 4721286 bytes, checksum: d81a0051c1f91a999e9ea8c3e9fe0b20 (MD5) Previous issue date: 2012 / Doutorado / Engenharia de Alimentos / Doutor em Engenharia de Alimentos
2

Elaboração e caracterização de biofilmes de farinha de biri (Canna indica L.) / Development and characterization of films based on Canna indica L. flour

Andrade Mahecha, Margarita Maria, 1979- 14 August 2018 (has links)
Orientadores: Florencia Cecilia Menegalli, Delia Rita Tapia Blacido / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-14T13:43:25Z (GMT). No. of bitstreams: 1 AndradeMahecha_MargaritaMaria_M.pdf: 13503554 bytes, checksum: 744c46669728d982aa8ab0cda3d79f8a (MD5) Previous issue date: 2009 / Resumo: O interesse em filmes biodegradavéis éuma tendência mundial que tem aumentado de modo significativo nos ?timos anos motivando assim, estudos relacionados com o desenvolvimento e caracterização de filmes a base de macromoléculas naturais. O objetivo deste trabalho foi elaborar biofilmes a partir de farinha de biri (Canna indica L.) e avaliar o efeito de quatro variaveis de processo: concentração de glicerol (15 ¿ 35%), temperatura de processo (70 ¿90 °C), temperatura de secagem (35 ¿ 55 °C) e umidade relativa de secagem (30 ¿ 70%) sobre as propriedades mecânicas (força, deformação, tensão, elongação e módulo secante), ópticas (cor, brilho e opacidade) e a solubilidade em água dos biofilmes. Na primeira etapa do trabalho, foram obtidos farinha e amido a partir de rizomas de biri cultivados no estado de São Paulo (Brasil). Estes materiais foram caracterizados quanto à composição centesimal, propriedades físicas e térmicas, análiise de microestrutura por microscopía eletrica de varredura (MEV), distribuição de tamanho dos grânulos de amido e análise estrutural por espectroscopia de absorção no infravermelho (FTIR). Numa segunda etapa, filmes a partir de farinha de biri foram elaborados segundo um Delineamento Composto Central Rotacional 24 (DCCR). Os resultados obtidos foram analisados estatisticamente empregando a metodologia de superfície de resposta (RSM) que juntamente com a função de desejabilidade (D) permitiu a obtenção das condiçoes de processo ótimas (concentração de glicerol de 17%, temperatura de processo de 90 °C, temperatura de secagem de 44,8 °C e umidade relativa de 36,4%). Nas condições ótimas os biofilmes apresentaram altos valores de resistência mecânica (7,0 MPa), baixa solubilidade (38,3%) e valores de elongação satisfatórios (14,6%). Na útima etapa do trabalho, foram elaborados biofilmes de farinha e de amido de biri para determinar o efeito das fibras, proteínas e lipídios sobre as propriedades dos filmes de farinha. Os biofilmes foram caracterizados com base em suas propriedades mecânicas, ópticas, microestrutura e analise estrutural por MEV e FTIR. Os biofilmes de farinha apresentaram maior flexibilidade em termos de elonga?o (14,6%), maior permeabilidade ao vapor de ?ua (5,3 ?0,2 x 10 ¿10 g.m/m2.h.Pa) e menor resistência mecânica e rigidez (7,0 N e 231,7 MPa) quando comparados com os biofilmes de amido de biri (1,4%; 18,6 N; 1772 MPa e 3,2 ± 0,01 x 10 -10 g.m/m2.h.Pa, respectivamente). A partir das análiises MEV, observouse que os biofilmes de farinha apresentaram imperfeições na sua superfície e uma seção transversal menos densa e com pequenas fissuras quando comparados com os biofilmes de amido. Os espectros de FTIR evidenciaram a presença De grupos OH, CH2 e amida III em ambos os biofilmes enquanto que o grupo amida I só foi evidenciado nos filmes de farinha. Em relação às propriedades ópticas, os filmes de farinha apresentaram cor amarelada enquanto que os filmes de amido apresentaram-se mais claros e menos opacos / Abstract: The focus in biodegradable films is a global trend and has received a significant attention in recent years, thus motivating studies related to the development and characterization of films based on natural macromolecules. The objective of this study is to develop edible films from biri flour (Canna indica L.) and evaluate the effect of four process variables: glycerol concentration (15 - 35%), process temperature (70 - 90 °C), drying temperature (35 ¿ 55 °C) and drying air relative humidity (30 ¿ 70%), on both mechanical (puncture force, deformation, tensile strength, elongation at break and secant modulus), and optical (color, brightness and opacity ) properties, as well as on water solubility of films. In the first stage of this work, flour and starch were obtained from rhizomes of biri cultivated in the S? Paulo State (Brazil). The evaluation of such materials dealt with proximate chemical composition, physical and thermal properties, microstructural analysis by Scanning Electron Microscopy (SEM), size distribution of starch granules and structural analysis by Fourier Transform Infrared (FTIR) spectroscopy. On the second stage, edible films from the biri flour were prepared according to a Central Composite Rotational Design 24 (CCRD). The results were statistically analyzed using the response surface methodology (RSM), which along with the desirability function (D) allowed to obtain the optimum process conditions (17% for glycerol concentration, 90 °C for process temperature, 44,8 °C for drying temperature and 36,4% for air drying relative humidity). In optimum conditions the films showed high values of tensile strength (7,0 MPa), low solubility (38,3%) and satisfactory values of elongation at break (14,6%). On the last stage of this work, the films were prepared from flour and starch biri in order to determine the effect of fiber, protein and fat on the properties of the flour biofilms. The films were characterized based on their mechanical and optical properties, microstructure and structural analysis by means of SEM and FTIR. The results showed that flour films have greater flexibility in terms of elongation at break (14,6%), high water vapor permeability (5,3 ?0,2 x 10 -10 g.m/m2.h.Pa) and lower tensile strength and secant modulus (7,0 N and 231,7 MPa) when compared with the starch films (1,4%; 18,6 N; 1772 MPa and 3,2 ?0,01 x 10 -10 g.m/m2.h.Pa respectively). From SEM analysis it was observed that the flour films have flaws in its surface and a cross section less dense, with small cracks compared with the starch films. FTIR spectra showed presence of OH groups, CH2 and amide III in both films, while the amide group I was only observed in flour film. Optical properties showed that the flour films were yellowish while the starch films were clearer and less opaque / Mestrado / Mestre em Engenharia de Alimentos
3

The Treatment of Swine Wastewater by Horizontal Biofilter and Subsurface Constructed Wetland

Hsieh, Hsiao-Yu 09 August 2011 (has links)
Swine wastewater is one of the major pollutions in Taiwan. The abundant nutrition and organic matters in it may lead eutrophication of water body. Meanwhile, the low dissolved oxygen level and high suspended solids concentration may also make it more difficult to handle the wastewater treatment. At present facility of swine wastewater in Taiwan is the three-process treatment which includes the solid-liquid separation, anaerobic digestion, and activated sludge system. Even though the three-process treatment is widely used, the efficiency of sediment and filter effectively to remove the nutrition, e.g., ammonia and phosphate is still in question. On the other hand, the activated sludge system is a difficult technique that the swine farmers can¡¦t easily to operate. Based on these reasons, an efficient swine wastewater treatment process should be established. In this study, we replace the activated sludge system in three-process treatment with the horizontal biofilter (HBF) and subsurface system constructed wetland (SFSCW) to assess the practicability of improving the traditional process. HBF is a fix-biofilm system which is superior to the suspended growth of activated sludge system by its simple operation and no need to return the sludge from the final clarifier. Porosity in the gravel of SFSCW and the root zone of Canna indica can also help to remove the nutrients from the outflow of HBF. The tested HRT (hydraulic retention time) has been controlled at about 30 hours and results show that SS, BOD and COD removal efficiencies as 84.07%, 86.48%, and 68.45%, respectively. HBF and SFSCW provided approximate 70~80% and 10~20% removal efficiencies, respectively. This design of combining HBF and SFSCW system has high potential to treat the swine wastewater, and adding the backwash unit may further facilitate the operation in the future.
4

Plant growth and nutrient removal in simulated secondary-treated municipal wastewater in wetland microcosmos

Zhang, Zhenhua January 2008 (has links)
[Truncated abstract] The use of constructed wetlands for tertiary purification of municipal wastewater has received increasing attention around the world because direct discharge of secondary-treated municipal wastewater to water bodies has caused eutrophication. Plant species selection and vegetation management may enhance nutrient removal efficiency in constructed wetlands. However, there is a lack of knowledge on the relations between plant growth and nutrient removal efficiency in constructed wetlands. The objective of this study is to better understand how plant growth and resource allocation are influenced by nutrients in wastewater and how nutrient removal efficiencies are affected by plant species and vegetation management. The preliminary experiment was conducted to select macrophytes, especially ornamental species, to grow in the wastewater in the wetland microcosms. Ten plant species, comprising six ornamental species: Alocasia macrorrhiza, Canna indica, Iris louisiana, Lythrum sp., Zantedeschia aethiopica, Zantedeschia sp., and four sedge species: Baumea articulate, Baumea juncea, Carex tereticaulis and Schoenoplectus validus, were planted in the wetland microcosms and fed a simulated wastewater solution in the concentrations similar to the secondary-treated municipal wastewater. C. indica has shown vigorous and healthy growth, and a relatively high potential of rooting-zone aeration and nutrient removal efficiency. B. articulata and S. validus also showed relatively high nutrient removal efficiency. ... The high nutrient availability and optimum N/P ratio were required for stimulating plant growth, resulting in allocation of more resources to above-ground tissues compared to below-ground parts, and enhancing nutrient removal efficiency. Nutrient removal efficiencies were significantly influenced by growth of C. indica and S. validus, nutrient loading rates and N/P ratios in the wastewater. The nutrient uptake kinetics of C. indica and S. validus were investigated to elucidate the differences in nutrient uptake between species. Wetland plant species have shown differential nutrient uptake efficiency and different preferences for inorganic N source, with C. indica preferring NO3-N and S. validus preferring NH4-N. C. indica had greater capacity than S. validus to take up PO4-P when the concentration of PO4-P in the solution was relatively low, whereas S. validus was more capable than C. indica to take up NO3-N when the concentration of NO3-N in the solution was relatively low. The PO4-P uptake capacity was higher in younger than older plants. Overall, the study has suggested that different plant species have differential capacity to take up nutrients. In addition to nutrient uptake, plants have significant other roles in terms of nutrient removal from the wastewater (such as leaking oxygen into the rhizosphere in which oxidation of substances like ammonia can occur). The properly high nutrient availability and optimum N/P ratio are required to stimulate the plant growth, resulting in enhancing the treatment performance in the wetlands. These findings have important implications for improving our ability to engineer ecological solutions to the problems associated with nutrient-rich wastewater.

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