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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

Avaliação de adjuvantes obtidos a partir de extratos de plantas bioativas / Evaluation of adjuvants derived from bioactive plant extracts

Müller, Lillian Espindola 12 August 2017 (has links)
Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-07-05T15:59:33Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Lillian Espindola Müller.pdf: 1571545 bytes, checksum: 45f2e65629e91e4df8579311ccb3058b (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-07-11T21:13:16Z (GMT) No. of bitstreams: 2 Dissertação Lillian Espindola Müller.pdf: 1571545 bytes, checksum: 45f2e65629e91e4df8579311ccb3058b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-07-11T21:13:16Z (GMT). No. of bitstreams: 2 Dissertação Lillian Espindola Müller.pdf: 1571545 bytes, checksum: 45f2e65629e91e4df8579311ccb3058b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-12 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / A necessidade de alternativas que tornem as aplicações mais eficientes no manejo fitossanitário é uma constante e para isto o uso de adjuvantes junto às caldas fitoprotetoras trazem grandes benefícios como o aumento na molhabilidade, na aderência, no espalhamento, a redução da tensão superficial e o ângulo de contato da gota e na dispersão da calda de pulverização, além de aumentar a penetração cuticular promovendo assim a eficácia contra espécies de difícil controle melhorando a atividade química e as características de aplicação. Com isso, este trabalho teve por objetivo investigar fontes de adjuvantes obtidas a partir de extratos de plantas bioativas. Foram avaliadas a presença de saponinas na composição fitoquímica, a qualidade saponosídica, o potencial tensoativo e adesivo e a melhor forma de preparo e concentração para cada espécie. As médias dos resultados obtidos pelos tratamentos foram comparadas estatisticamente pelo teste de Tukey, em nível de 5% de probabilidade. A presença de saponinas foi constatada na maioria das espécies analisadas com qualidades distintas, obtendo-se maior capacidade tensoativa para o fator de comparação utilizado (sabão neutro) enquanto a maior capacidade adesiva foi observada na espécie Aloe vera. A melhor forma de preparo e concentração se deu de acordo com as análises realizadas, sendo que para os tensoativos os melhores resultados foram através da massa seca e triturada enquanto que para os adesivos a forma verde processada em suco obteve maior destaque. No entanto ainda são necessários maiores estudos quanto às concentrações e associações passíveis de serem utilizadas no manejo fitossanitário para a agricultura familiar. / The need for alternatives which make the most efficient applications in plant management is constant and that the use of adjuvants together with the grout fitoprotetoras bring great benefits as increased wettability in adhering, the spreading, to reduce the surface tension and the angle contact drop and dispersion of the spray solution, in addition to increasing cuticular penetration thereby promoting effective against species unwieldy improving the chemical activity and application characteristics. Therefore, this study aimed to investigate sources of adjuvants derived from bioactive plant extracts. We evaluated the presence of saponins in phytochemical composition, saponosídica quality, surfactant and adhesive potential and the best way of preparation and concentration for each species. The average results for the treatments were compared statistically by the Tukey test at the level of 5% probability. The presence of saponins was observed in most of the species analyzed with distinct qualities, obtaining higher surface-active capacity for comparison factor used (neutral soap) while the higher adhesive strength was observed in the Aloe vera species. The best form of preparation and concentration was in accordance with the analysis carried out, and for the surfactants the best results were dried and crushed through mass while for the adhesives processed green form in juice obtained greater prominence. However further studies are still needed as the concentrations and associations that can be used in pest management for family farming.
2

Développement de bio-composites à base de fibres végétales et de colles écologiques / Development of plant fibers and ecological adhesives bio-based composites

Saad, Houda 19 December 2013 (has links)
L’intégration des fibres naturelles cellulosiques de plantes annuelles ou de résidus agricoles ou agro-industriels dans l’élaboration de matériaux de structures composites et le développement de nouveaux liants biosourcés sont aujourd’hui un domaine de recherche d’intérêt croissant. La thèse s'est déroulée dans le cadre du programme « Eco-panneaux », dont les deux objectifs principaux furent tout d'abord de valoriser les fibres végétales d’origine tunisienne comme l’alfa, le jonc et les folioles de palme et ensuite d'évaluer le potentiel d'espèces végétales tunisiennes dont les écorces sont riches en tannins (fruit de grenade, racines du sumac et tronc de pin d’Alep). Les études de caractérisation des fibres ont montré que leurs masses volumiques sont inférieures à 1. Le calcul du point de saturation des fibres (FSP) montre des valeurs majoritairement comprises entre 60 et 100 %. Nous avons également pu caractériser la cinétique d'imprégnation d'eau pour chacune des fibres. L’imprégnation se stabilise après 24 h d’immersion. Riches en minéraux (concentrations supérieures à 1 %), les fibres ont montré des teneurs en cellulose, en lignines et en hémicellulose comparables à celles généralement rencontrées avec les fibres de bois. L’analyse thermogravimétrique (ATG) a permis de constater que les matrices végétales étudiées sont thermiquement stables pour des températures inférieures à 200°C. Le dosage colorimétrique pour étudier la composition en polyphénols des matrices tannifères, l’analyse infrarouge et l’étude structurale de l’extrait des tanins, ainsi que le calcul du « Stiasny number » , montrent la forte teneur de l’écorce de grenade en tanins hydrolysables et la richesse des écorces du tronc de pin d’Alep et des racines du sumac en tanins condensés. L’étude des propriétés thermiques des extraits de tanins par ATG montre que les tanins de pin d’Alep et du sumac sont thermiquement plus stables que ceux de la grenade. La colle formulée à partir d’hexamine et de tanins de pin d’Alep présente un module d’élasticité élevé. Alors que la colle à base de tanins de grenade forme le réseau le moins dense. Ces résultats ont été confirmés par l’étude de la résistance au cisaillement. L'étude réalisée sur les composites fibres-plâtre (mise en œuvre et caractérisation physico mécanique des composites) a montré que les fibres locales pourraient constituer une alternative aux fibres d'importation utilisées actuellement. Une première caractérisation de la conductivité thermique des panneaux isolants élaborés à partir des fibres locales et de colles de tanins montre une conductivité thermique moyenne de 0,106w/K.m. / The integration of natural cellulosic fibers from annual plants and agricultural residues and agro-industrial materials in the development of composite structures and the development of new bio-based adhesives, are now a research field with growing interest. The thesis was conducted within the framework of "Eco-panels" program, which its two main objectives were firstly, to enhance plant fibers of Tunisian origin as alfa, rush and palm leaflets and then to evaluate the potential of Tunisian plant species whose bark is rich in tannins (pomegranate fruit, sumac roots and Aleppo pine trunk). The characterization studies of fibers showed that their densities are less than 1. The calculation of the fiber saturation point (FSP) shows values mostly between 60 and 100 %. We were also able to characterize the impregnation kinetics of water for each of these fibers. The impregnation stabilizes after 24 h of immersion. Rich in minerals (concentrations greater than 1 %), the fibers showed levels of cellulose, lignin and hemicellulose comparable to those generally encountered with wood fibers. The thermogravimetric analysis (TGA) shows that the plant matrices are thermally stable for temperatures below 200 ° C. The colorimetric assay of the polyphenolic composition of tanniferous matrices, the infrared analysis and the structural study of the tannins extract, as well as the calculation of "Stiasny number" show the high content in hydrolysable tannins for pomegranate barks and richness of Aleppo pine trunk barks and sumac roots barks in condensed tannins. The study by TGA of the thermal properties of tannins extracts shows that Aleppo pine and sumac tannins are thermally more stable than those of pomegranate. The formulation made from hexamine and Aleppo pine tannins has the greatest elasticity modulus. While the formulation prepared from pomegranate tannins forms the least dense network. These results were confirmed by the study of the shear strength. The study conducted on fiber-plaster composites (implementation and physico-mechanical characterization of composites) showed that local fiber could be an alternative to imported fibers used currently. A first characterization of the thermal conductivity of insulation panels made from local plant fibers and tannins adhesives shows an average conductivity of 0,106 W / Km.
3

Mechanisch-enzymatischer Aufschluss von Kartoffelpülpe als Bindemittel zur Herstellung von Holzwerkstoffen / Mechanical-enzymatic decomposition of potato-pulp and the utilization as adhesive for wood-based composites

Müller, Cora 30 June 2005 (has links)
No description available.
4

Entwicklung eines naturnahen Bindemittels aus nachwachsenden Rohstoffen auf Proteinbasis zur Herstellung von Mitteldichten Faserplatten / Development of a near-natural protein based bonding agent for the production of medium density fibreboards

Schöpper, Christian 15 March 2006 (has links)
No description available.

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