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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.
31

Utilization of Sorghum in El Salvador: Grain, Flour and End-Product Quality

Pinilla, Luz Eliana 2010 December 1900 (has links)
There is limited information on the utilization of sorghum for human consumption in El Salvador. Increased wheat prices have driven the baking industry to seek alternative cereals for manufacturing of their products. The white color and bland taste characteristics of Salvadorian sorghum is ideal for use as a partial substitute of wheat (up to 50 percent) or alone in baked goods and a wide variety of foods. Further information on the grain quality, milling characteristics and impact on end-product was assessed to make better use of the available grain. Three different varieties of improved and local cultivars (RCV, Native and ZAM 912) were evaluated for their grain, flour and end-product quality. Grain hardness, color and composition of the grains varied from hard to intermediate to soft. Burr, hammer and roller milling were used for sorghum flour production. Impact of grain characteristics and milling quality was evaluated through the flours produced and their end-product quality. Grain hardness significantly affects flour and final product characteristics. Harder grain, RCV, produced flours more difficult to cook and with a grittier texture than those produced from Native cultivars (floury endosperm). Cupcakes produced from harder grain flours had lower volume and harder texture than cupcakes made from the Native varieties. ZAM 912 was an intermediate hard sorghum variety and produced the darkest flour and darkest cupcakes due to its pericarp hue. Appropriate use of this grain’s flour can be used in baked products with a darker hue (e.g. chocolate pastries). Harder grain flours can be utilized in coarse crumb products (e.g. cookies, horchata, and atole). Hammer mills produced the coarsest particles for all the varieties evaluated. Burr mills produced flour with similar cooking and end-product texture qualities as the roller mill. However, burr mills are not suitable for production of large quantities of whole sorghum flour. Nevertheless, they are more affordable for small entrepreneurs. Cultivars analyzed produce quality flour that can be used in an array of baked foods, i.e. ethnic beverages, porridges, cookies, flour mixes, tortillas, sweet breads. Whole sorghum flour substitution as low as 25 percent in wheat-based foods can represent significant cost savings for its users.
32

A Novel Design/Fabrication for Micro Fuel Cell Stack Bipolar Plates and Performance Tests

Feng, Chih-Lun 20 July 2006 (has links)
The H2/air micro PEMFC stacks were designed and fabricated in-house through MEMS (Micro-Electro-Mechanical System) technology with deep UV lithography manufacturing processes (SU-8 photoresist) and micro electroforming manufacturing processes to construct a novel metallic bipolar plate. The effect of different operating parameters on micro PEMFC stacks performance was experimentally investigated for serpentine flow-field configuration. Experiments were conducted through a serious laboratory experiments with different operating conditions of temperature (25oC, 35 oC and 50 oC), anode backpressures (97kPa, 153kPa, 207kPa) as well as anode humidifier temperature (25oC, 35 oC and 50 oC). Experimental results are presented in the form of polarization VI curves and PI curves under above operating conditions. The influence of the aforementioned parameters was presented and discussed.
33

Study of The Analytical Method for Chromium(VI) in Seawater

Huang, Li-Li 28 August 2006 (has links)
In this research, in order to set up the ultimate approaches to determine the content of chromium(¢¾) in seawater, different pH values, the amount of chelating agent, chelating time and extraction time were investigated in two different solvent extraction systems, APDC-MIBK and Aliquat 336-MIBK. In APDC-MIBK system, the ultimate extracting condition is that 400 mL sample is adjusted to pH 3.0, added 4 % APDC 4 mL to chelate chromium(¢¾) for 60 minutes, and added 20 mL MIBK to partiton into two fractions for 5 minutes. The recovery in APDC-MIBK system is 68 %~ 123 %. The method detection limit is 0.2 ppb. In Aliquat 336-MIBK system, the ultimate extracting condition is that 400 mL sample is adjusted to pH 2.0, added 5 % Aliquat 336 4 mL to chelate chromium(¢¾), added 20 mL MIBK to be shaken for 2 minutes, and partitoned into two fractions for 5 minutes. The recovery in Aliquat 336-MIBK system is 80 %~ 120 %. The method detection limit is 0.1ppb. Although in APDC-MIBK system assorted metals can be extracted at same time, it is steadier in Aliquat 336-MIBK system than APDC-MIBK system. Therefore, it is a feasible extraction method to adopt Aliquat 336-MIBK system to determine the content of chromium(¢¾) in seawater.
34

Ochratoxin A in overripe grapes, raisings and special wines in vitro and in vivo studies on fungi isolated from grapes and raisins affected by physical, chemical and biotic agents

Valero Rello, Ana 13 July 2007 (has links)
Ochratoxin A (OTA) is a fungal secondary metabolite produced by Aspergillus and Penicillium species. It has been detected in a wide range of commodities, including cereals, coffee, grapes, raisins, must and wine. Within grape derivative products, the raisins, red wine and sweet wines have reported to contain the highest OTA levels. Aspergillus section Nigri (A. niger and A. carbonarius) are considered the OTA source in these commodities and they are commonly isolated among other fungi from grapes and raisins.Starting from this basis the objectives of this thesis were focused into three main aspects: (1) Evaluation of the food products: vine dried fruits and special wines, concerning the mycobiota and OTA occurrence and incidence; (2) Ecophysiological studies of the ochratoxigenic fungi and accompanying mycobiota as affected by environmental conditions; (3) Control and preventive methods such as the evaluation of residual activity of pre-harvest fungicides during grape dehydration and the use of modified atmospheres.Wine origin and winemaking procedure showed to be determinant for the final OTA content. All special wines analysed from northern European regions were negative for OTA while more than 50% of wines from warmer regions were positive for OTA contamination. The wines with higher OTA levels were fortified musts followed by those made from dried grapes. Acoholic and malo-lactic fermentations, biological 'crianza' (Flor yeast) and the action of Botrytis cinerea in noble rot of grapes may diminish the OTA levels in wine.In grapes, the presence of Aspergillus section Nigri became predominant at harvest and mainly during sun-drying. Prevalence of Aspergillus section Nigri can be explained by their adaptation to environmental conditions of sun-drying, and by their ability to dominate other fungal species involved when coming into contact with them. Among the Aspergillus section Nigri, A. niger aggregate was dominant, although A. carbonarius increased its inci
35

Samarbete i grupp : En studie i hur idrottslärare arbetar med gruppens samarbete i ämnet Idrott och Hälsa.

Holm, Johan, Kjellqvist, Marc January 2012 (has links)
Syftet med vår uppsats är att undersöka vilka metoder och strategier idrottslärare använder för att få elever att samarbeta i grupp. Detta utifrån arbetssätt som konflikthantering och kommunikation. Vidare var vår mening att undersöka vad lärarna ansåg att deras arbetsmetoder hade för effekter på eleverna.   Vår teori bygger vi på Svedbergs (2007, s.192) modell som presenterar hur gruppens samarbete beror på tre faktorer i lärandet.   Metoden i undersökningen bygger på kvalitativa intervjuer med öppna frågor. Tanken var att undersöka vad som var det centrala i lärarnas arbetsmetoder för att främja gruppsamarbetet i undervisningen. Vidare ville vi även undersöka hur de intervjuade lärarna beskriver sin ledarstil. Till undersökningen valdes sex idrottslärare där samtliga arbetade på skolor som var skilda från varandra. Med tanke på att två av dessa lärare för närvarande arbetar på gymnasiet, och resterande på högstadiet, kan det ha en påverkan på våra resultat.     Utifrån undersökningens resultat fann vi att gruppens samarbete beror på hur läraren använder sina arbetsverktyg med hjälp av de riktlinjer som kursplanen idrott och hälsa och skolans värdegrund belyser kring gruppsamarbete. Dessa arbetsverktyg tolkade vi till att kommunikationen var det centrala arbetsverktyget för lärare för att främja gruppsamarbetet. Inom kommunikationen belyste lärarna feedback, konflikthantering och att skapa en trygg miljö bland eleverna. Resultaten visade även att det råder liten skillnad i vilka arbetsmetoder lärarna använder i undervisningen. Ett antagande vi gör är att arbetslagen lärare ingår i på skolan har en avgörande roll för hur lärare arbetar, med tanke på att resultaten visar på små skillnader för hur lärare med större yrkesvana kontra lärare med mindre yrkesvana arbetar. Syftet med lektionen var även en avgörande faktor till vilken arbetsmetod som valdes. Samtliga lärare beskriver sitt ledarskap som en demokratisk ledarstil med en handledarroll.
36

Growth and Characterization of ZnSe and ZnTe Alloy Nanowires

Li, Zhong 06 December 2012 (has links)
The objective of this thesis is to explore the synthesis and characterization of high quality binary ZnTe nanowires with great potential for development of optoelectronic devices including high efficiency photovoltaic cells for energy conversion and high sensitivity photodetectors for green fluorescent protein bioimaging at single molecule level. To systematically explore the fabrication process for high quality nanowires, a chemical vapour deposition system was built for nanowire growth. Computational fluid dynamics simulations were used to optimize the reactor and growth parameters. The simulations were validated by experimental measurements. Room temperature photoluminescence measurements showed that high crystal quality with very low defects by single step growth was achieved. This single step growth technique makes a great improvement compared to the reported growth followed by annealing, which achieved equivalent crystal quality. This simplification could be of use in large scale synthesis of nanowires. The simulation results also showed that reactant species concentration is a key factor influencing the growth. A metal-organic chemical vapour deposition system was thus built to independently control reactant concentrations for ZnTe nanowire growth. Temperature-dependent photoluminescence measurements of as-grown ZnTe nanowires showed a strong near band-edge emission. In addition, a deep level oxygen-related band was observed for the first time. From the detailed analysis of thermal quenching of the photoluminescence, it was shown that the deep level emission was partially from the intermediate band of the material. This is of great importance due to the theoretical absorption efficiency that is as high as 63% for intermediate band materials, which is more than two times of that of current single junction concentrators, and few materials possessing this property. Individual ZnTe nanowires, grown after optimization, were patterned and contacted, and their conductivity and photoconductivity were measured at room temperature. A single ZnTe nanowire serving as a photodetector was shown to have the highest reported visible responsivity of 360 A/W (at 530 nm), and a gain of 8,640 (at 3 V bias). The responsivity is roughly 18 times higher than that of silicon avalanche photodiodes. This demonstrates that ZnTe nanowires are strong candidates for single photon detection.
37

Föräldraskap i ”Nya Vi Föräldrar” : En kvalitativ analys av en tidnings framställning av småbarnsföräldrar

Brandt, Sara January 2014 (has links)
Syftet med denna uppsats är att undersöka hur tidningen ”Nya Vi Föräldrar” framställer småbarnsföräldrar i utvalda reportage. Metoden för arbetet är kvalitativ innehållsanalys och visuell metod eftersom reportagen består av både text och bild. Analysen grundar sig på teorier från Anthony Giddens, Yvonne Hirdman och Erving Goffman. I analysarbetet har det vuxit fram olika teman som sedan har blivit mina specifika avsnitt. Det första avsnittet i analysen heter ”Vardagens organisering” och handlar främst om hur familjerna talar om rutiner och planering, det andra avsnittet ”Arbetsfördelning” beskriver hur föräldrarna talar om hushållssysslor och omsorg av barnen. Vidare behandlar avsnittet ”Framställningen av mammor och pappor” hur framför allt tidningen har valt att framställa könen i reportagens bilder och slutligen beskrivs exempel på hur bilderna är komponerade under avsnittet ”Bildkomponering”. Analysen visar framförallt att föräldraskapets traditionella könsroller som manligt och kvinnligt fortfarande är en central del i föräldrarnas vardag. Det synliggörs också genom hur föräldrarna ser på sig själva och hur tidningen väljer att framställa dem. I analysen kan man se att viljan till jämställdhet är något som eftersträvas av både familjerna och tidningen genom tankar och framställningar.
38

Growth and Characterization of ZnSe and ZnTe Alloy Nanowires

Li, Zhong 06 December 2012 (has links)
The objective of this thesis is to explore the synthesis and characterization of high quality binary ZnTe nanowires with great potential for development of optoelectronic devices including high efficiency photovoltaic cells for energy conversion and high sensitivity photodetectors for green fluorescent protein bioimaging at single molecule level. To systematically explore the fabrication process for high quality nanowires, a chemical vapour deposition system was built for nanowire growth. Computational fluid dynamics simulations were used to optimize the reactor and growth parameters. The simulations were validated by experimental measurements. Room temperature photoluminescence measurements showed that high crystal quality with very low defects by single step growth was achieved. This single step growth technique makes a great improvement compared to the reported growth followed by annealing, which achieved equivalent crystal quality. This simplification could be of use in large scale synthesis of nanowires. The simulation results also showed that reactant species concentration is a key factor influencing the growth. A metal-organic chemical vapour deposition system was thus built to independently control reactant concentrations for ZnTe nanowire growth. Temperature-dependent photoluminescence measurements of as-grown ZnTe nanowires showed a strong near band-edge emission. In addition, a deep level oxygen-related band was observed for the first time. From the detailed analysis of thermal quenching of the photoluminescence, it was shown that the deep level emission was partially from the intermediate band of the material. This is of great importance due to the theoretical absorption efficiency that is as high as 63% for intermediate band materials, which is more than two times of that of current single junction concentrators, and few materials possessing this property. Individual ZnTe nanowires, grown after optimization, were patterned and contacted, and their conductivity and photoconductivity were measured at room temperature. A single ZnTe nanowire serving as a photodetector was shown to have the highest reported visible responsivity of 360 A/W (at 530 nm), and a gain of 8,640 (at 3 V bias). The responsivity is roughly 18 times higher than that of silicon avalanche photodiodes. This demonstrates that ZnTe nanowires are strong candidates for single photon detection.
39

Geschichte der kolonialen demarkation zwischen Spanien und Portugal, 1493-1750

Oppliger, Friedrich. January 1913 (has links)
Inaug.-Diss.--Bern. / "Literatur": 1 p. at end.
40

Análise de mutações no gene arilsulfatase B em pacientes com mucopolissacaridose tipo VI do Brasil : definição de uma possível origem comum em Monte Santo/BA

Motta, Fabiana Maia Moura Costa January 2011 (has links)
Mucopolissacaridose tipo VI é uma doença lisossômica causada pela deficiência de arilsulfatase B. A incidência de MPS VI é muito baixa, geralmente menos de 1 caso para cada 1.000.000 recém-nascidos. Até o presente momento, 133 mutações e 13 polimorfismos foram identificados no gene da arilsulfatase B. Entretanto, a maioria dos alelos mutantes ou está presente somente em um indivíduo ou em poucos pacientes, o que demonstra a grande heterogeneidade alélica da MPS VI. No município de Monte Santo, Nordeste do Brasil, foram identificados treze pacientes com MPS VI. O objetivo deste trabalho foi identificar a(s) mutação(ões) presente(s) nos pacientes com MPS VI de Monte Santo/BA e os heterozigotos nas famílias; definir haplótipos utilizando SNPs para identificação de uma possível origem comum do alelo mutado nesta população e permitir aconselhamento genético eficiente, bem como orientações sobre a doença aos familiares com indivíduos afetados. Os 13 pacientes com MPS VI apresentavam a mutação p.H178L em homozigose e o mesmo haplótipo para os SNPs intragênicos. Nas viagens realizadas até o município durante este trabalho foram coletadas 236 amostras de sangue dos familiares, a mutação p.H178L foi detectada em 98 (20,8%) alelos, sendo 41,5% da amostra composta por indivíduos heterozigotos. Com base em dados atuais, a prevalência de MPS VI nesta região é estimada em 1:5.000 recémnascidos. As análises dos heredogramas indicam a presença de vários indivíduos com chance de 25% ou até 50% de serem heterozigotos. Monte Santo é uma região pequena e isolada e, os altos índices de endogamia fazem com que o alelo p.H178L permaneça frequente nesta região. Estes resultados, juntamente com a análise dos heredogramas, sugerem um efeito fundador, o que reforça a necessidade de um programa abrangente de genética comunitária para esta área, incluindo uma triagem neonatal e estudos com os membros das famílias para promover um aconselhamento genético. / Mucopolysaccharidosis type VI is a lysosomal disease caused by deficiency of arylsulfatase B. The incidence of MPS VI is very low, usually less than 1 case for every 1,000,000 newborns. To date, 133 mutations and 13 polymorphisms were identified in the arylsulfatase B gene. However, the majority of mutant alleles are present only in one individual or in a few patients, demonstrating the allelic heterogeneity of MPS VI. In the county of Monte Santo, northeast Brazil, thirteen patients with MPS VI were identified. The objective of this study was to characterize the mutation(s) present(s) in MPS VI patients from Monte Santo/BA and to detect heterozygous within the families. We also aimed to define haplotypes using SNPs to identify a possible common origin of the mutant allele in this population and allow efficient genetic counseling and assistance regarding the disease to families with affected individuals. The 13 MPS VI patients showed the p.H178L mutation in homozygosis and the same haplotype for intragenic SNPs. During field trips to Monte Santo along this study we collected 236 blood samples from family members, p.H178L mutation was detected in 98 (20.8%) alleles, and 41.5% of the samples were heterozygous individuals. Based on current data, the prevalence of MPS VI in this region is estimated at 1:5,000 newborns. Pedigree analysis indicates the presence of many individuals with a 50% and 25% chance of being heterozygous. Monte Santo is a small, isolated region and the high levels of inbreeding allows for p.H178L allele to remain common in this region. These results, together with the analysis of pedigrees suggest a founder effect, which reinforces the need for a comprehensive program of community genetics in this area, including a neonatal screening and studies of family members to promote a genetic counseling.

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