• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • 1
  • Tagged with
  • 4
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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

Phenolic compounds in Ecuadorian fruits /

Vasco, Catalina, January 2009 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2009. / Härtill 5 uppsatser.
2

Anaerobic digestion at mesophilic and thermophilic temperature : with emphasis on degradation of phenols and structures of microbial communities /

Levén, Lotta, January 2006 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2006. / Härtill 3 uppsatser.
3

Variabilidade de compostos fenólicos e voláteis durante o amadurecimento de frutos de três variedades de Eugenia uniflora L. / Variability of phenolic and volatile compounds during the fruit ripening of three varieties of Eugenia uniflora L.

Ramalho, Ruver Rodrigues Feitosa 23 September 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-11-19T12:44:41Z No. of bitstreams: 2 Dissertação - Ruver Rodriques Feitosa Ramalho - 2015.pdf: 3672502 bytes, checksum: 9452919a961824a1718a9111d9ee60ad (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-11-19T12:46:53Z (GMT) No. of bitstreams: 2 Dissertação - Ruver Rodriques Feitosa Ramalho - 2015.pdf: 3672502 bytes, checksum: 9452919a961824a1718a9111d9ee60ad (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-11-19T12:46:53Z (GMT). No. of bitstreams: 2 Dissertação - Ruver Rodriques Feitosa Ramalho - 2015.pdf: 3672502 bytes, checksum: 9452919a961824a1718a9111d9ee60ad (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-09-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The composition of essential oils and the content of phenolic compounds in fruits of three varieties of pitanga (fruits red, red-orange and purple) were analyzed for four ripening stages. The analysis of variance (two-way ANOVA) showed that the anthocyanins differ significantly between the three pitanga varieties, especially at the final stage. Levels of flavonoids varied during maturation differently for each variety, and only at the third stage the levels of these metabolites were similar for the three varieties. No differences were observed in tannin concentrations during fruit ripening and total phenols between the three varieties. Through analysis by GC/MS was possible to identify a total of 28 substances in essential oils of pitanga fruit. The red variety was characterized by the presence of germacrone (39.67-46.54%) curzerene (14.36- 15.75%) and atractylone (6.90-10.10%), while the red-orange presents as major compounds: selina-1,3,7(11)-trien-8-one (36.06-41.22%) and selina-1,3,7(11)-trien-8- one epoxide (19.36-34.28%). The purple variety contains germacrone (51.56-56.80%), curzerene (4.10-5.11%), atractylone (0.72-1.50%), selina-1,3,7(11)-trien-8-one (11.04- 14.31%) and selina-1,3,7(11)-trien-8-one epoxide (3.70-5.86%). Total sesquiterpenes are the major constituents of the fruits of the three varieties at all stages of maturation, and the oxygenated sesquiterpenes were more abundant in red and purple varieties, while hydrocarbons sesquiterpenes were dominant in the red-orange variety. Generally no significant differences were observed in the concentrations of the major volatile compounds of the three varieties during the period of maturation, only the orange-red variety showed variations in the total levels of sesquiterpenes and monoterpenes. It was concluded that the composition of essential oils and anthocyanin levels are the factors that distinguish the three varieties, while in relation to the ripening process the anthocyanins, flavonoids, phenolic compounds and some minor constituents of the oils have varied significantly. / A composição de óleos essenciais e os teores de compostos fenólicos em frutos de três variedades de pitanga (frutos vermelho, vermelho-laranja e roxo) foram analisados durante quatro estádios de maturação. A análise de variância (ANOVA two-way) mostrou que os teores de antocianinas diferem significativamente entre as três variedades de pitanga, principalmente no último estádio. Teores de flavonóides variaram durante a maturação de forma diferente para cada variedade e somente no terceiro estádio os níveis destes metabólitos foram iguais para as três variedades. Não foram observadas diferenças nas concentrações de taninos durante o amadurecimento dos frutos e de fenóis totais entre as três variedades. Através de análise por CG/EM foi possível identificar no total 28 substâncias nos óleos essenciais dos frutos de pitanga. A variedade vermelha foi caracterizada pela presença de germacrona (39,67-46,54%), curzereno (14,36-15,75%) e atractilona (6,90-10,10%), enquanto a variedade vermelhaalaranjada possui como compostos majoritários: selina-1,3,7(11)-trien-8-one (36,06- 41,22%) e epóxido de selina-1,3,7(11)-trien-8-one (19,36-34,28%). A variedade roxa contém tanto germacrona (51,56-56,80%), curzereno (4,10-5,11%) e atractilona (0,72- 1,50%) quanto selina-1,3,7(11)-trien-8-one (11,04-14,31%) e epóxido de selina- 1,3,7(11)-trien-8-one (3,70-5,86%). Os sesquiterpenos totais são os constituintes majoritários dos frutos das três variedades em todos os estádios de maturação, sendo que os sesquiterpenos oxigenados foram mais abundantes nas variedades vermelha e roxa, enquanto os hidrocarboneto sesquiterpênicos foram dominantes na variedade vermelha-alaranjada. Em geral não foram observadas diferenças significativas nas concentrações dos compostos voláteis majoritários das três variedades durante o período de maturação, somente a variedade vermelho-alaranjada apresentou variações nos teores totais de sesquiterpenos e monoterpenos. Concluiu-se que a composição dos óleos essenciais e os níveis de antocianinas são os fatores que mais distinguem as três variedades, em relação ao processo de amadurecimento dos frutos temos que antocianinas, flavonóides, fenóis totais e alguns constituintes minoritários dos óleos variaram de forma significativa.
4

Werkstoffeinflüsse auf den Spritzgussprozess von hochgefüllten Phenol-Formaldehydharz­-Formmassen

Scheffler, Thomas 11 January 2019 (has links)
Im Rahmen der vorliegenden Arbeit wurden verschiedene duroplastische Formmassen laboranalytisch hinsichtlich der rheologischen und thermischen Eigenschaften untersucht. Es wurde u.a. gezielt die absolute Materialfeuchte gesteigert, um den Einfluss dieser auf das Fließ­ Härtungsverhalten zu charakterisieren. Anschließend wurden die Materialien auf einer hochinstrumentierten Spritzgussmaschine mit einem Fließspiralenwerkzeug untersucht. Dabei konnte ein direkter Zusammenhang zwischen dem Rückfluss und dem Plastifizierdrehmoment in Abhängigkeit der Materialfeuchte und der Prozessparameter detektiert werden . Des Weiteren wurden über die Differenzdruckmessung im Fließspiralenwerkzeug die scheinbaren Viskositäten über den Fließweg ermittelt. Hierbei konnten unterschiedliche Aufschmelzeffekte über die Fließweglänge in Abhängigke it der duroplastischen Formmasse, der absoluten Materialfeuchte und der Prozessparameter detektiert werden . Durch Schererwärmung konnte die Formmassentemperatur teilweise die Werkzeugtemperatur übersteigen. Hinsichtlich der mechanischen Eigenschaften (Schlagzähigkeit, Biegefestigkeit) konnten keine signifikanten Einflussgrößen detektiert werden. Hinsichtlich des Tg konnten systematischen Unterschiede detektiert und begründet werden. Die beste Möglichkeit zur Ermittlung des Tg lieferte die TMA. Die thermischen Glasübergänge korrelieren mit den in der DSC ermittelten Aushärtegraden , wobei mit steigender Materialfeuchte ein geringer Aushärtegrad detektiert wird. / Within this paper, the rheologieal and thermie eharaeteristies of different thermosetting molding eompounds were investigated using lab analysis methods. Among others, the absolute moisture eontent was inereased purposefully to investigate its influenee on the flow-euring behavior. Subsequently, the materials were analyzed using a highly instrumented injeetion-molding maehine and a flow spiral tool. A direet link between the baekflow and the plastifieation torque dependent on the moisture eontent and proeess parameters was deteeted . Furthermore, a measurement of the differential pressure was eondueted within the flow spiral to deteet the apparent viseosity over the flow path. Within this proeess, different melting effeets over the flow eurve length depending on the molding eompound, the absolute moisture eontent and proeess parameters were deteeted. The shear heating lead to a material temperature inerease of the molding eompound, whieh was partly higher than the tool temperature . Coneerning the meehanieal eharaeteristies (impaet strength, flexural strength), no signifieant influeneing faetors eould be deteeted. In eontrast, systematie differenees of the glass transition temperature were deteeted and their eause eould be explained. The best way to determine the glass transition is the TMA. The glass transition temperatures eorrelate with the degree of eure determined with the DSC, whereas an inereasing moisture eontent is assoeiated with a lower degree of eure.

Page generated in 0.0507 seconds