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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

Accelerated aging of thick glass second surface silvered reflectors under sandstorm conditions

Caron, Simon January 2011 (has links)
Concentrated solar power systems are expected to be sited in desert locations where the direct normal irradiation is above 1800 kWh/m2.year. These systems include large solar collector assemblies, which account for a significant share of the investment cost. Solarreflectors are the main components of these solar collector assemblies and dust/sand storms may affect their reflectance properties, either by soiling or by surface abrasion. While soiling can be reverted by cleaning, surface abrasion is a non reversible degradation.The aim of this project was to study the accelerated aging of second surface silvered thickglass solar reflectors under simulated sandstorm conditions and develop a multi-parametric model which relates the specular reflectance loss to dust/sand storm parameters: wind velocity, dust concentration and time of exposure. This project focused on the degradation caused by surface abrasion.Sandstorm conditions were simulated in a prototype environmental test chamber. Material samples (6cm x 6cm) were exposed to Arizona coarse test dust. The dust stream impactedthese material samples at a perpendicular angle. Both wind velocity and dust concentrationwere maintained at a stable level for each accelerated aging test. The total exposure time in the test chamber was limited to 1 hour. Each accelerated aging test was interrupted every 4 minutes to measure the specular reflectance of the material sample after cleaning.The accelerated aging test campaign had to be aborted prematurely due to a contamination of the dust concentration sensor. A robust multi-parametric degradation model could thus not be derived. The experimental data showed that the specular reflectance loss decreasedeither linearly or exponentially with exposure time, so that a degradation rate could be defined as a single modeling parameter. A correlation should be derived to relate this degradation rate to control parameters such as wind velocity and dust/sand concentration.The sandstorm chamber design would have to be updated before performing further accelerated aging test campaigns. The design upgrade should improve both the reliability of the test equipment and the repeatability of accelerated aging tests. An outdoor exposure test campaign should be launched in deserts to learn more about the intensity, frequencyand duration of dust/sand storms. This campaign would also serve to correlate the results of outdoor exposure tests with accelerated exposure tests in order to develop a robust service lifetime prediction model for different types of solar reflector materials.
2

Accelerated Aging Effects on Kevlar KM2 Fiber Survivability

Yang, Tony 02 October 2013 (has links)
Kevlar materials offer excellent tensile and thermal properties but can rapidly degrade under exposure to hot and humid environmental conditions. Currently Kevlar fiber's survival probability comes from a single filament test. Unfortunately, the single filament test is a tedious process and prone to operator bias, leading to inaccurate survival function that does not represent the actual survival function. This research aims to validate the fiber bundle test to replace the single filament test in extracting Kevlar’s survival function. Another important aspect is determining the factors that cause the fiber to lose its properties. This research also aims to determine the factors that degrade Kevlar fibers and those factors’ combined effects on degrading the KM2 fiber. This information is essential for safety factor design when exposure to these environmental factors would cause the Kevlar KM2 to fail prematurely. Results from experimental data and analysis indicate that the fiber bundle test is a good replacement for single filament tests and estimation techniques can determine the bundle Weibull parameters. Furthermore, the survival function for treated fibers is better if the bundle is lubricated. The accelerated aging experiments show that accelerated aging is possible with combined temperature and moisture. Kevlar KM2 bundle conditioned at 270 °C and 150 g water for 3 hours lost over 95% of its breaking strength. This is comparable to Kevlar bundles treated for over 500 hours in 250 °C or treated for over 100 days in 100% relative humidity environment at 80 °C found in literature.
3

Estudo in vitro da estabilidade de cor e opacidade de cinco sistemas cerâmicos sob influência do envelhecimento artificial acelerado / \"In vitro\" study of color stability and opacity of five ceramic systems under influence of accelerated aging

Luciana de Paula Ribeiro dos Santos Porto 30 July 2007 (has links)
O objetivo deste estudo foi avaliar a estabilidade de cor e opacidade de cinco sistemas cerâmicos glazeados naturalmente e com pintura extrínseca, utilizando os espectrofotômetros Color Guide 45/0 (BYK-Gardner) e Easyshade (Vita), sob influência do envelhecimento artificial acelerado. Foram confeccionados 14 corpos de prova para cada grupo testado de cerâmica - metalocerâmica Ceramco 3 (Dentsply) (grupo 1), cerâmica pura Ceramco 3 (grupo 2), cerâmica pura EX -3 (Noritake) (grupo 3), Vitroceram (Angelus) recoberta com Allceram (Degudent) (grupo 4) e Vitroceram recoberta com Cerabien (Noritake) (grupo 5). Sete corpos de prova de cada grupo cerâmico foram glazeados naturalmente e sete foram submetidos à pintura extrínseca com pigmento Vita Chrom 712. Uma leitura inicial foi realizada em todos os corpos de prova utilizando o espectrofotômetro Color Guide, obtendo valores de opacidade e das coordenadas L*, a*, b* e E*; e utilizando o espectrofotômetro Easyshade, obtendo valores de L*, C*, h* e E*. Após o envelhecimento artificial de 500h, foram realizadas novas leituras nos espectrofotômetros. Os resultados encontrados foram submetidos à análise estatística e concluiu-se que os grupos 2, 3 e 4 foram influenciados estatisticamente pelo envelhecimento artificial acelerado quanto à opacidade; e que o grupo 5 foi o que obteve o pior desempenho de estabilidade de cor (E* = 3,32 - VTCE e E* = 2,68 = VTCEPE) para o espectrofotômetro Color Guide. Com o espectrofotômetro Easyshade os grupos 4 e 5 e as cerâmicas MC, CER, EX foram considerados ineficazes quanto à estabilidade de cor (p<0,05). / The aim of this study was to evaluate the color stability and opacity of five ceramic systems naturally glazed and with extrinsic porcelain colorant, under influence of accelerated aging, using two spectrophotometers Color Guide 45/0 (BYK-Gardner) and Easyshade (Vita) as a tool for color and opacity measurement. Fourteen samples were provided for each tested group of ceramics: metal-ceramic Ceramco3 (Dentsply) (Group 1), Ceramco3 (Group 2), EX3 (Noritake) (Group 3), Vitroceram (Angelus) with Allceram (Degudent) (Group 4) and Vitroceram with Cerabien (Noritake) (Group 5). Seven samples of each group were submitted to extrinsic colorant (Vita Chrom 712) and the other seven were naturally glazed. An initial measurement was performed and the values of opacity, L*, a*, b* and E* were obtained using the Color Guide spectrophotometer, and using Easyshade the values of L*, C*, h* and E* were obtained. After the process of 500h accelerated aging a new measurement was performed for all samples. The results were statistically analyzed and the conclusion was that the opacity of groups 2, 3 and 4 were statistically influenced by the accelerated aging and the group 5 had the worst assessment in color stability (E* = 3,32 - VTCE e E* = 2,68 - VTCEPE) with the Color Guide spectrophotometer. With Easyshade, groups 4 and 5 and MC, CER and EX ceramics were considered ineffective as for color stability (p<0,05).
4

Estudo in vitro da estabilidade de cor e opacidade de cinco sistemas cerâmicos sob influência do envelhecimento artificial acelerado / \"In vitro\" study of color stability and opacity of five ceramic systems under influence of accelerated aging

Porto, Luciana de Paula Ribeiro dos Santos 30 July 2007 (has links)
O objetivo deste estudo foi avaliar a estabilidade de cor e opacidade de cinco sistemas cerâmicos glazeados naturalmente e com pintura extrínseca, utilizando os espectrofotômetros Color Guide 45/0 (BYK-Gardner) e Easyshade (Vita), sob influência do envelhecimento artificial acelerado. Foram confeccionados 14 corpos de prova para cada grupo testado de cerâmica - metalocerâmica Ceramco 3 (Dentsply) (grupo 1), cerâmica pura Ceramco 3 (grupo 2), cerâmica pura EX -3 (Noritake) (grupo 3), Vitroceram (Angelus) recoberta com Allceram (Degudent) (grupo 4) e Vitroceram recoberta com Cerabien (Noritake) (grupo 5). Sete corpos de prova de cada grupo cerâmico foram glazeados naturalmente e sete foram submetidos à pintura extrínseca com pigmento Vita Chrom 712. Uma leitura inicial foi realizada em todos os corpos de prova utilizando o espectrofotômetro Color Guide, obtendo valores de opacidade e das coordenadas L*, a*, b* e E*; e utilizando o espectrofotômetro Easyshade, obtendo valores de L*, C*, h* e E*. Após o envelhecimento artificial de 500h, foram realizadas novas leituras nos espectrofotômetros. Os resultados encontrados foram submetidos à análise estatística e concluiu-se que os grupos 2, 3 e 4 foram influenciados estatisticamente pelo envelhecimento artificial acelerado quanto à opacidade; e que o grupo 5 foi o que obteve o pior desempenho de estabilidade de cor (E* = 3,32 - VTCE e E* = 2,68 = VTCEPE) para o espectrofotômetro Color Guide. Com o espectrofotômetro Easyshade os grupos 4 e 5 e as cerâmicas MC, CER, EX foram considerados ineficazes quanto à estabilidade de cor (p<0,05). / The aim of this study was to evaluate the color stability and opacity of five ceramic systems naturally glazed and with extrinsic porcelain colorant, under influence of accelerated aging, using two spectrophotometers Color Guide 45/0 (BYK-Gardner) and Easyshade (Vita) as a tool for color and opacity measurement. Fourteen samples were provided for each tested group of ceramics: metal-ceramic Ceramco3 (Dentsply) (Group 1), Ceramco3 (Group 2), EX3 (Noritake) (Group 3), Vitroceram (Angelus) with Allceram (Degudent) (Group 4) and Vitroceram with Cerabien (Noritake) (Group 5). Seven samples of each group were submitted to extrinsic colorant (Vita Chrom 712) and the other seven were naturally glazed. An initial measurement was performed and the values of opacity, L*, a*, b* and E* were obtained using the Color Guide spectrophotometer, and using Easyshade the values of L*, C*, h* and E* were obtained. After the process of 500h accelerated aging a new measurement was performed for all samples. The results were statistically analyzed and the conclusion was that the opacity of groups 2, 3 and 4 were statistically influenced by the accelerated aging and the group 5 had the worst assessment in color stability (E* = 3,32 - VTCE e E* = 2,68 - VTCEPE) with the Color Guide spectrophotometer. With Easyshade, groups 4 and 5 and MC, CER and EX ceramics were considered ineffective as for color stability (p<0,05).
5

橋梁支承用ゴムの環境劣化特性に関する基礎的研究

伊藤, 義人, ITOH, Yoshito, 矢澤, 晃夫, YAZAWA, Akio, 佐藤, 和也, SATOH, Kazuya, 顧, 浩声, GU, Haosheng, 惣那, 幸浩, KUTSUNA, Yukihiro, 山本, 吉久, YAMAMOTO, Yoshihisa 07 1900 (has links)
No description available.
6

Project ABSS : Adhesive bonding of stainless steels

Andersson, Viktor, Larsson, Andreas January 2017 (has links)
This report aims to increase the scientific knowledge about long-term prospects for the adhesive and adhesive joints for bonding of stainless steels. The effects of water, temperature and chemicals on the adhesive and adhesive joints are investigated. Stainless steel plates are pretreated with a primer and isopropanol, there after joined together with single lap modeling. The strength of the joint is tested with a tensile test and additionally a watertightness test is performed to determine if the joints are watertight. For this project three versions of stainless steels is used and two different technologies of two- part adhesives, silicone and silane-modified polymer and one technology of tape, a double coated acrylic foam tape are tested. The result shows that all the adhesives fails cohesively and that tape fails partly adhesively. Result shows that all tests are affected by water, temperature and chemicals on different levels but tape is affected the most with a minimum of 40% loss in shear strength. Watertightness test shows that aged tape joints are not watertight. The polymer shows no signs of decreasing in shear strength and is watertight, but does become more viscous by aging. The report shows that a possible combination of adhesive and pretreatment that can withstand the effects of water, temperature and chemicals is found. The polymer presents a possibility to bond stainless steel with a simple pretreatment. Tape didn’t pass the test in a suitable way but presents opportunities if a sufficient pretreatment can be found.
7

Aluminium alloys ability to catalyse the oxidation of biodiesel : Development of a procedure to test alloys

Khudur, Ivan January 2017 (has links)
Biodiesel is a renewable and biodegradable fuel that has the possibility to replace conventional diesel fuel and reduce the environmental pollution. Despite its environmental benefits, it has been shown to cause damage to the vehicle engines, due to its oxidative properties. Different metals, such as copper, zinc and aluminium are present in the vehicle fuel system and have been shown to catalyse the oxidation of biodiesel. Several studies have been performed to investigate the interaction between these metals and fuel. However, some reports concluded contradicting results when it comes to the oxidation of biodiesel in contact with aluminium alloys. This project aimed therefore to investigate and create a simple method for comparing the catalytic effect on oxidation for metals, and use this method to evaluate the degradation rate of biodiesel in contact with aluminium alloys. Different heating methods and coating materials were tested using the biodiesel RME to develop the testing procedure. When a test procedure was established, three filter houses made from cast aluminium alloy and three aluminium ingots with different amount of copper were immersed in RME and the stability was evaluated. The results showed that using an oven at 80 °C to investigate the stability provided the most repeatable results, and the spray paint Auto K billack spray Universal appeared to be compatible to use with RME. The inner untreated surface of the fuel filter houses did not seem to increase the oxidation rate of biodiesel. Aluminium alloys with higher copper content degraded RME more than aluminium alloys with little/no copper, if the surface had been treated mechanically, but not to a large extent. This concludes that aluminium alloys may reduce the stability of biodiesel if it contains much copper and if the surface of the alloy has been treated. However, the detected reduction on oxidation stability could depend on other factors, and therefore it is recommended to conduct further experiments on test the aluminium alloys. / Biodiesel är ett förnybart och biologiskt nedbrytbart bränsle som har möjligheten att ersätta konventionell diesel och minska föroreningen av miljön. Trots dess fördelar så har det visats att bränslet skadar motorerna i fordon, vilket beror på dess oxidativa egenskaper. Olika metaller, såsom koppar, zink och aluminium förekommer i fordons bränslesystem, och dessa har påvisats katalysera oxidationen av biodiesel. Flera studier har genomförts där interaktionen mellan de tidigare nämnda metallerna och biodiesel har undersökts. En del av dessa studier har fått motsägelsefulla resultat när det kommer till interaktionen mellan aluminium legeringar ochbiodiesel. Detta projekt har därför haft som syfte att ta fram en enkelt metod att jämföra metallers katalystiska effekt på biodieslets oxidations stabilitet, samt använda denna metod för att bedöma nedbrytningen av biodiesel i kontakt med aluminium legeringar. Olika uppvärmningsmetoder och täckningsmaterial undersöktes med hjälp av biodiesel gjord på rapsolja, RME, för att ta fram mätmetoden. När ett tillvägagångssätt hade fastlagts, så sänktes bitar av tre olika bränslefilterhus tillverkade av aluminium legeringar, och tre olika aluminium tackor med olika kopparhalter i RME och bränslets stabilitet mättes. Användning av ugn vid 80 °C för att testa biodieslets oxidations stabilitet gav de mest upprepbara resultaten, och sprejfärgen Auto K billack spray Universal var mest kompatibel att använda som täckningsmaterial. Den inre, obehandlade ytan av bränslefilterhusen visade sig inte påverka oxidations stabiliteten på biodieslet. Aluminijm legeringar med en högre koppar halt bröt ned RME lite mer än aluminium legeringar med lite/ingen koppas, men endast om ytan hade blivit mekaniskt behandlad. Detta ger slutsatsen att aluminium legeringar kan minska biodieslets stabilitet om det innehåller mycket koppar och om legeringens yta har blivit behandlad. Däremot så kan den reduktionen av oxidations stabiliteten bero på andra faktorer och det rekommenderas därför att genomföra fler experiment med aluminum legeringar och biodiesel.
8

Aluminium alloys ability to catalyse the oxidation of biodiesel : Development of a procedure to test alloys

Khudur, Ivan January 2017 (has links)
Biodiesel is a renewable and biodegradable fuel that has the possibility to replace conventional diesel fuel and reduce the environmental pollution. Despite its environmental benefits, it has been shown to cause damage to the vehicle engines, due to its oxidative properties. Different metals, such as copper, zinc and aluminium are present in the vehicle fuel system and have been shown to catalyse the oxidation of biodiesel. Several studies have been performed to investigate the interaction between these metals and fuel. However, some reports concluded contradicting results when it comes to the oxidation of biodiesel in contact with aluminium alloys. This project aimed therefore to investigate and create a simple method for comparing the catalytic effect on oxidation for metals, and use this method to evaluate the degradation rate of biodiesel in contact with aluminium alloys. Different heating methods and coating materials were tested using the biodiesel RME to develop the testing procedure. When a test procedure was established, three filter houses made from cast aluminium alloy and three aluminium ingots with different amount of copper were immersed in RME and the stability was evaluated. The results showed that using an oven at 80 °C to investigate the stability provided the most repeatable results, and the spray paint Auto K billack spray Universal appeared to be compatible to use with RME. The inner untreated surface of the fuel filter houses did not seem to increase the oxidation rate of biodiesel. Aluminium alloys with higher copper content degraded RME more than aluminium alloys with little/no copper, if the surface had been treated mechanically, but not to a large extent. This concludes that aluminium alloys may reduce the stability of biodiesel if it contains much copper and if the surface of the alloy has been treated. However, the detected reduction on oxidation stability could depend on other factors, and therefore it is recommended to conduct further experiments on test the aluminium alloys. / Biodiesel är ett förnybart och biologiskt nedbrytbart bränsle som har möjligheten att ersätta konventionell diesel och minska föroreningen av miljön. Trots dess fördelar så har det visats att bränslet skadar motorerna i fordon, vilket beror på dess oxidativa egenskaper. Olika metaller, såsom koppar, zink och aluminium förekommer i fordons bränslesystem, och dessa har påvisats katalysera oxidationen av biodiesel. Flera studier har genomförts där interaktionen mellan de tidigare nämnda metallerna och biodiesel har undersökts. En del av dessa studier har fått motsägelsefulla resultat när det kommer till interaktionen mellan aluminium legeringar ochbiodiesel. Detta projekt har därför haft som syfte att ta fram en enkelt metod att jämföra metallers katalystiska effekt på biodieslets oxidations stabilitet, samt använda denna metod för att bedöma nedbrytningen av biodiesel i kontakt med aluminium legeringar. Olika uppvärmningsmetoder och täckningsmaterial undersöktes med hjälp av biodiesel gjord på rapsolja, RME, för att ta fram mätmetoden. När ett tillvägagångssätt hade fastlagts, så sänktes bitar av tre olika bränslefilterhus tillverkade av aluminium legeringar, och tre olika aluminium tackor med olika kopparhalter i RME och bränslets stabilitet mättes. Användning av ugn vid 80 °C för att testa biodieslets oxidations stabilitet gav de mest upprepbara resultaten, och sprejfärgen Auto K billack spray Universal var mest kompatibel att använda som täckningsmaterial. Den inre, obehandlade ytan av bränslefilterhusen visade sig inte påverka oxidations stabiliteten på biodieslet. Aluminijm legeringar med en högre koppar halt bröt ned RME lite mer än aluminium legeringar med lite/ingen koppas, men endast om ytan hade blivit mekaniskt behandlad. Detta ger slutsatsen att aluminium legeringar kan minska biodieslets stabilitet om det innehåller mycket koppar och om legeringens yta har blivit behandlad. Däremot så kan den reduktionen av oxidations stabiliteten bero på andra faktorer och det rekommenderas därför att genomföra fler experiment med aluminum legeringar och biodiesel.
9

Produtividade e qualidade fisiológica de sementes de Trifolium pratense na região serrana de santa Catarina / Productivity and physiological quality of clover-red seeds(Trifolium pratense L.) in the Santa Catarina

Belizário, Karla Katy 08 September 2016 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-02-26T12:56:08Z No. of bitstreams: 1 PGPV16MA194.pdf: 1071160 bytes, checksum: 532abfafc565e7d83c257ec9a501bd35 (MD5) / Made available in DSpace on 2018-02-26T12:56:08Z (GMT). No. of bitstreams: 1 PGPV16MA194.pdf: 1071160 bytes, checksum: 532abfafc565e7d83c257ec9a501bd35 (MD5) Previous issue date: 2016-09-08 / FAPESC / The success in the establishment, production and storage of seeds depends on the physiological quality. The objective was evaluate the physiological quality and red clover seed yield of cultivars and Quiniquelli and Estanzuela 116, sown in two locations in the mountainous region of Santa Catarina State in 2014/2015 and 2015/2016 seasons. The seeds of the crop 2014/2015 were compared with seeds from Rio Grande do Sul crop harvested in the 2013/2014 and 2015/2016 crop seeds were compared with seeds harvested in the 2014/2015 crop. To assess the viability of the seeds was carried out the germination test (20°C, 10 days in germination chamber). The physiological quality was estimate by the accelerated aging test with saline (42°C, 48 h aging chamber) and seedling length (measured in cm with universal caliper). Productivity was established by harvest all mature inflorescences of the floor area of 3 m2 per repetition, 4 replicates per cultivar and the result was expressed in kg.ha. Regarding the effect the accelerated aging test, there was a reduction of 78% to 116 Estanzuela cultivate the environment 2. The productivity of seeds was higher for cultivar Estanzuela 116 independent environmental and crop, highlighting yet this cultivar in the first crop environment 1 with 304.84 kg / ha. The cultivar Estanzuela 116 was more promising for serrana region of Santa Catarina State / O sucesso no estabelecimento da pastagem, assim como a produção e armazenamento das sementes depende da qualidade fisiológica destas. O objetivo do trabalho foi verificar a qualidade fisiológica e a produtividade de sementes de trevo-vermelho das cultivares Quiniquelli e Estanzuela 116, semeadas a campo em dois ambientes (1 e 2) da região serrana de Santa Catarina nas safras 2014/2015 e 2015/2016. As sementes da safra 2014/2015 foram semeadas em épocas diferentes (19/05/2014 e 12/06/2014) e foram comparadas com sementes provenientes do Rio Grande do Sul colhidas da safra 2013/2014 e as sementes da safra 2015/2016 foram semeadas em uma única época (18/05/2015) e foram comparadas com as sementes colhidas na safra 2014/2015. Para avaliar a germinação colocou-se as sementes em câmara de germinação a 20°C por um período de 10 dias. A determinação do vigor foi estimada através do teste de envelhecimento acelerado com solução salina (42°C; 48 h em câmara de envelhecimento) e comprimento de plântulas (medidas em cm com paquímetro universal). A produtividade foi estabelecida pela colheita de todas as inflorescências maduras da área útil de 3 m2 por repetição, sendo 4 repetições por cultivar e o resultado foi expresso em kg ha-1. Com relação ao vigor pelo teste de envelhecimento acelerado, observou-se redução para a cultivar Estanzuela 116 no ambiente 2. A produtividade das sementes foi maior para a cultivar Estanzuela 116 independente do ambiente e da safra, destacando-se ainda esta cultivar no ambiente 1 da primeira safra, com 304,84 kg/ha. A cultivar Estanzuela 116, para produção de sementes, mostrou-se mais promissora para a região Serrana de Santa Catarina
10

Desempenho em laboratório e em campo de sementes de milho submetidas a diferentes tempos de envelhecimento

Nogueira, Débora Cristiane [UNESP] 02 September 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-09-02Bitstream added on 2014-06-13T19:46:24Z : No. of bitstreams: 1 nogueira_dc_dr_ilha.pdf: 465474 bytes, checksum: 73aaf83a41766ac828cf08b26abed5fe (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O uso de sementes com alto nível de vigor é fundamental para o sucesso de um empreendimento agrícola, pois apresentam melhor desempenho em campo, resultando em maior produção. O objetivo do trabalho foi verificar o nível do vigor em sementes de três híbridos de milho submetidas ao envelhecimento acelerado e seus desempenhos em laboratório e em campo. Para tanto sementes dos híbridos AG-5020, AG-8088 e BG-7049 foram envelhecidas artificialmente à 41oC por 0, 48 e 72 horas e secadas em estufa à 38 °C/48 horas para a formação dos diferentes lotes. Experimento 1 – No laboratório, verificou-se o nível de vigor e o desempenho das sementes dos diferentes lotes por meio de análises de germinação, primeira contagem, deterioração controlada, tetrazólio, comprimento de raiz primária e mesocótilo, número de raízes/plântula, massa de matéria seca de plântula e emergência em solo. Experimento 2 – No campo as sementes foram semeadas manualmente em parcelas de 8 linhas de 5m, espaçamento de 0,5m e densidade de 80.000 plantas ha-1. Verificou-se o nível de vigor e o desempenho das plantas em campo pelas avaliações de características morfológicas das plantas, caracteres da espiga e componentes de produtividade. O delineamento experimental foi o inteiramente casualizado com os tratamentos obtidos da combinação 3 x 3 (híbridos x níveis de vigor) com quatro repetições. Em laboratório as sementes mais vigorosas apresentaram melhores desempenhos e em campo proporcionaram a obtenção de maior produtividade, o que se deve principalmente ao maior estande final obtido. As características das plantas e das espigas estão relacionadas ao genótipo de cada híbrido não se verificando efeito do vigor das sementes / The use of seeds with high level of vigor is fundamental to the success of an agricultural development, since its have better performance in the field, resulting in increased production. The objective of this study was to assess the level of vigor in seeds of three maize hybrids submitted to accelerated aging and their performance in laboratory and field. Seeds of AG-5020, AG-8088 and BG-7049 were artificially aged at 41°C for 0, 48 and 72 hours and dried in an stove at 38 °C /48 hours for the formation of the different lots. Experiment 1 – in the laboratory, we found the level of vigor and the performance of different seed lots by means of analysis of germination, first count, controlled deterioration, tetrazolium, length of primary root and mesocotyl, number of roots/seedling, seedling mass dry matter and seedling emergence in soil. Experiment -2 the seeds were manually sown in plots of 8 rows of 5m, 0,5 m spacing and density of 80000 plants ha-1. The level of vigor and performance of plants in the field evaluations of morphological characteristics of plants, components and characters of the spike in productivity. The experimental design was completely randomized treatments obtained with the combination 3 x 3 (hybrid x vigor levels) with four replications. In the laboratory the most vigorous seeds showed better performances and the field higher productivity, which is mainly due to higher final stand. As characteristics of plants and spike are related to the genotype of each hybrid was not observed effect of vigor seeds

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