Teste de condutividade elétrica em sementes de maracujazeiro-amarelo

O teste de condutividade elétrica pode proporcionar informações importantes e complementares sobre o potencial fisiológico de sementes em período de tempo relativamente curto, visto que o teste de germinação se completa aos 28 dias para sementes de maracujá. Dessa forma, o objetivo deste trabalho foi avaliar a eficiência do teste de condutividade elétrica na avaliação do potencial fisiológico e padronizar a metodologia para sementes de maracujá-amarelo. Quatro lotes de sementes foram submetidos aos testes de germinação e vigor (primeira contagem, envelhecimento acelerado, índice de velocidade de germinação e emergência de plântulas em casa de vegetação), incluindo o teste de condutividade elétrica, conduzido com 25 e 50 sementes imersas em 50 e 75 mL de água desionizada,e as leituras realizadas após três, seis, nove, 12 e 24 h de embebição. Somente o lote 2 apresentou comportamento de baixo vigor apontado pelos testes de primeira contagem, emergência de plântulas e condutividade elétrica. A determinação do vigor de sementes de maracujá-amarelo por meio do teste de condutividade elétrica pode ser realizada utilizando 50 sementes e 75 mL após 24 h de embebição.

Teste de envelhecimento acelerado para avaliação do potencial fisiológico de sementes de grama-bermuda

A utilização de sementes para formação de gramados esportivos e ornamentais tem assumido grande importância no Brasil, principalmente pelo baixo custo em relação à formação por placas de tapetes naturais. As bermudas [Cynodon dactylon (L.) Pers] são as principais gramas utilizadas na formação de campos esportivos e, dentre os problemas enfrentados, destaca-se a dificuldade de estabelecimento adequado da cultura, fato que exige a utilização de sementes de alto potencial fisiológico, de modo a permitir rápida emergência e desenvolvimento das plantas. Assim, estudaram-se procedimentos para a condução do teste de envelhecimento acelerado para determinar o potencial fisiológico de sementes dessa espécie, incluindo a avaliação da eficiência do uso de solução saturada de NaCl como alternativa para a realização do teste. Para tanto, cinco lotes de sementes foram submetidos aos testes de germinação, emergência de plântulas e envelhecimento acelerado (períodos de 48, 72 e 96 h, a 41 e 45 ºC, com e sem o uso de solução saturada de NaCl). O experimento foi conduzido em delineamento inteiramente casualizado. O envelhecimento acelerado com o uso de solução saturada de NaCl, dentre os procedimentos estudados, é o método mais adequado para avaliação do potencial fisiológico de sementes de grama-bermuda, sendo que a combinação 45 ºC/48 h é eficiente para a classificação dos lotes em diferentes níveis de vigor.

Teste de condutividade elétrica para sementes de mamoneira

The aim was to study the efficiency of electrical conductivity test in evaluating the quality of castor seeds. Emergence of seedlings was evaluated in the field, with five seed lots of cv. AL Guarany 2002. The seeds were submitted to the following tests: germination; first count of germination; accelerated aging (45 degrees C by 24 to 100% UR), emergence of seedlings in the field, rate of speed of development of seedlings and electrical conductivity, testing the periods (2, 4, 6, 8 and 24 hours) and the number of seeds (25,50 and 75) in 75ml of distilled water conditioning to 25 degrees C. A completely randomized design was used. The averages were compared by the Tukey test at 5%. The mean laboratory and field test data were correlated. Electrical conductivity test for 4 hours with 25 seeds and 6 hours with 50 seeds, and the rate of speed emergency proved efficient in the selection of lots vigor by providing information equivalent to the emergence of seedlings in the field.

Vermiculita como substrato para o teste de germinação de sementes de ipê-amarelo

Vermiculite is a substrate used in seedling production of forest species and can be an option for the germination test of ipe seeds. The objective of this research was to evaluate the use of vermiculite in the germination test of Tabebuia chrysotricha seeds and to stablish appropriate particle size and moisture for this substrate. Four replications of 20 seeds were sown in soil, sand, paper rolls, and vermiculite with different particle sizes: micron (0.15-0.20 mm), superthin (0.21-0.30 mm), thin (0.30-0.50 mm) and medium (0.50-1.19 mm) moistened with water equivalent to 0.5, 1.0, 1.5 and 2.0 times the weight of the dry subtrate. Germination test was carried out at 30 degrees C. The percentage of normal seedlings was obtained seven days after sowing (first count) and then weekly until 28 days, when abnormal seedlings and dead seeds were also counted. It was concluded that the germination test of ipe seeds can be carried out with thin or medium vermiculite moistened with water equivalent to 1.5 times the dry weight of the substrate. These treatments resulted in higher and faster germination (21 days).

Um sistema para estimação da vazão de gás de poços produzindo por Plunger Lift para vaso separador de teste em plataformas de petróleo

This work intends to analyze the behavior of the gas flow of plunger lift wells producing to well testing separators in offshore production platforms to aim a technical procedure to estimate the gas flow during the slug production period. The motivation for this work appeared from the expectation of some wells equipped with plunger lift method by PETROBRAS in Ubarana sea field located at Rio Grande do Norte State coast where the produced fluids measurement is made in well testing separators at the platform. The oil artificial lift method called plunger lift is used when the available energy of the reservoir is not high enough to overcome all the necessary load losses to lift the oil from the bottom of the well to the surface continuously. This method consists, basically, in one free piston acting as a mechanical interface between the formation gas and the produced liquids, greatly increasing the well s lifting efficiency. A pneumatic control valve is mounted at the flow line to control the cycles. When this valve opens, the plunger starts to move from the bottom to the surface of the well lifting all the oil and gas that are above it until to reach the well test separator where the fluids are measured. The well test separator is used to measure all the volumes produced by the well during a certain period of time called production test. In most cases, the separators are designed to measure stabilized flow, in other words, reasonably constant flow by the use of level and pressure electronic controllers (PLC) and by assumption of a steady pressure inside the separator. With plunger lift wells the liquid and gas flow at the surface are cyclical and unstable what causes the appearance of slugs inside the separator, mainly in the gas phase, because introduce significant errors in the measurement system (e.g.: overrange error). The flow gas analysis proposed in this work is based on two mathematical models used together: i) a plunger lift well model proposed by Baruzzi [1] with later modifications made by Bolonhini [2] to built a plunger lift simulator; ii) a two-phase separator model (gas + liquid) based from a three-phase separator model (gas + oil + water) proposed by Nunes [3]. Based on the models above and with field data collected from the well test separator of PUB-02 platform (Ubarana sea field) it was possible to demonstrate that the output gas flow of the separator can be estimate, with a reasonable precision, from the control signal of the Pressure Control Valve (PCV). Several models of the System Identification Toolbox from MATLAB® were analyzed to evaluate which one better fit to the data collected from the field. For validation of the models, it was used the AIC criterion, as well as a variant of the cross validation criterion. The ARX model performance was the best one to fit to the data and, this way, we decided to evaluate a recursive algorithm (RARX) also with real time data. The results were quite promising that indicating the viability to estimate the output gas flow rate from a plunger lift well producing to a well test separator, with the built-in information of the control signal to the PCV

Nota científica: teste de aceitação de bebida mista de soja e amora

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Teste de acidez graxa como índice de qualidade em arroz

Pesquisas visando a redução de perdas de grãos e sementes durante o armazenamento têm ocupado destaque em vários países. Dentro deste contexto, a avaliação da eficácia de um índice de qualidade de boa aplicabilidade, com metodologia simples e de resposta imediata visando tomadas rápidas de decisão é de suma importância. O presente trabalho, conduzido no Laboratório de Processamento de Produtos Agrícolas UNESP, Botucatu/SP teve como objetivos: (a) estabelecer correspondência entre o nível de ácidos graxos livres e as classes de vigor em sementes; (b) estabelecer correspondência entre o nível de ácidos graxos livres e a classificação comercial por tipos, em grãos de arroz (Oryza sativa L.). A correspondência entre o nível de ácidos livres e as classes de vigor em sementes foi avaliada utilizando-se sementes envelhecidas artificialmente, obtendo-se assim níveis diferenciados de vigor. A correspondência entre o nível de ácidos graxos livres e a classificação por tipos, em grãos de arroz, foi realizada utilizando-se amostras de arroz com as porcentagens máximas de grãos defeituosos permitidos pela legislação vigente. Utilizou-se a análise de variância de um delineamento inteiramente ao acaso e, para comparação entre médias, aplicou-se o teste de Tukey ao nível de 5% de probabilidade. Por meio dos resultados obtidos, observou-se que o teste de acidez graxa mostrou-se exeqüível para avaliar o vigor de sementes de arroz. Na pesquisa que buscava uma correspondência entre os valores de acidez graxa e classificação comercial, os dados revelaram a tendência do nível de ácidos graxos livres acompanhar a classificação comercial por tipos.

Eficácia do teste de acidez graxa na avaliação da qualidade do café Arábica (Coffea arabica L.) submetido a diferente períodos e temperaturas de secagem

This work had the aim of evaluating the effect of different temperatures and pre-drying periods on yard on the chemical composition and quality of the beverage of peeled cherry coffee. Temperatures of 40 degrees C, 50 degrees C and 60 degrees C were used in the mass with air flow of 20m(3)m(-1)m(2). After drying, the visible defects of the coffee samples were removed. For evaluation of quality, the following analyses were performed: sensorial analyses, total sugars, reducing sugars and non-reducing sugars, electrical conductivity, potassium leaching and fatty acidity. One verified that lower drying temperature and greater pre-drying period had contributed for the attainment of a better quality drink. The increase of temperature and pre-drying periods decreased the non-reducing sugars content while the values of reducing sugars increased. The electrical conductivity, potassium leaching and fatty acidity increased significantly with the rise of temperature and potassium leaching reduced with increasing of the pre-drying period. The fatty acidity test showed to be sensible to the drying temperature.

Pré-condicionamento das sementes de mamoneira para o teste de tetrazólio

Preconditioning of castor bean seeds for the tetrazolium test. This research had the objective of standardizing the methodology for preconditioning of castor bean (Ricinus communis L.) seeds for the evaluation of their physiological potential by the tetrazolium test. The evaluated seed preconditioning methods were: seeds with coat between moist paper towel at 30, 35 and 40 degrees C for 6, 8, 10, 12, 14, 16 and 18 hours; and seeds without coat between moist paper towel; and seeds with coat immersed in water, at 25, 30, 35 and 40 degrees C for 1, 2, 3, 4, 5 and 6 hours. After preconditioning, the seed coat was removed, the seeds were cut lengthwise, and immersed in tetrazolium solution at a concentration of 0.2% for 120 minutes at 35 degrees C. The seeds' germination percentage, moisture content before and after preconditioning, and staining uniformity after the tetrazolium were evaluated. The statistical design was completely randomized, and the means comparisons were accomplished by the Tukey test at 0.05 level of probability. It was concluded that castor bean seeds should be preconditioned with coat between moist paper towel at 35 degrees C for 12 hours, so that the results of the tetrazolium test will be similar to those obtained in the germination test.

Procedimento para condução do teste de envelhecimento acelerado em sementes de algodão

The evaluation of the effect of seed has been fundamental tool in the program of quality control, and the accelerated aging test, an important part of that process. Some authors report that the germination and vigor are associated with seed size and facing the lack of consensus for the use of this test methodology and the relationship of seed size on the physiological quality, this work aimed to adapt the existing methodology as the temperature and period of conditioning on the performance of two sizes of seed cotton. The seeds were classified into two meshes of sieves, and then subjected to tests of water content, germination and electrical conductivity. The experimental design was completely randomized, analyzed statistically in a factorial threefold. Seeds of different sizes, showed no difference in percentage of germination. Seeds subjected to 40 degrees C for 42h of conditioning showed better percentage of germination.

Desenvolvimento de material compósito a base de raspa de pneu e látex para isolamento térmico

The process of recycling has been stimulated by the markets for several reasons, mainly on economical and environmental. Several products have been developed from recycled materials that already exist as well as several residues have been studied in different forms of applications. The greater majority of the applications for thermal insulation in the domestic, commercial and industrial systems have been elaborated in the temperature ranges between low to medium reaching up to 180oC. Many materials such as glass wool, rock wool, polystyrene are being used which are aggressive to the environment. Such materials in spite of the effectiveness in the retention of heat flow, they cost more and when discarded take several years to be absorbed by the nature. This way, in order to adapt to a world politics concerning the preservation of the environment, the present study was intended to develop a material composed of natural/biodegradable materials and industrial residues. The development of such a product in the form of a composite material based on tyre scrapes and latex for thermal insulation is presented in this research work. Thermal and physical properties of the tire scrapes as well as latex were studied in order to use them as raw materials for the manufacture of the intended composite to be applied as a thermal insulator in hot and cold systems varying between 0ºC and 200oC, respectively. Composite blankets were manufactured manually, in weight proportions of 1:1 (50:50%); 1:2 (33:67%) and 2:1 (67:33%) (tire scrapes: latex) respectively. Physical, mechanical and thermal properties of the composites were analyzed to obtain data about the viability of using the composite as a thermal insulator. The analyses carried out were based on standards ABNT, ASTM and UL. The maximum temperature obtained for the composite as a thermal insulator was 200ºC, which meets the range of applications that could be used as a thermal insulator in domestic as well as industrial purposes. The experimental results prove that the composite can be used as a thermal insulator on heated or cooled surface

Desenvolvimento e teste de um protótipo de reator de plasma com gaiola catódica rotatória para nitretação em lote de pequenas peças

The technique of ion nitriding, despite being fully consolidated in the industry, has great limitations when applied to the treatment of small parts. This is because effects that occur due to non-uniformity of the electric field, generate localized heating in parts, damaging the uniformity of nitrided layer. In addition, because the samples are treated static parts thereof are untreated. To expand the use of plasma nitriding, this work presents the development, assembly and testing of a prototype plasma reactor with rotatory cathodic cage [patent pending], able to meet these needs, giving the material a uniform treatment and opening doors to industrial scale production. The samples tested with hexagonal nuts are 6.0 mm in diameter, made of stainless steel AISI 304 nitrided at a pressure of 1 mbar in an atmosphere of 20% H2 + 80% N2 for 1 h. After treatment, testing visual inspection, optical microscopy and microhardness were carried out to check the effectiveness of the process for uniformity and hardness of the parts. All samples exhibited uniform color, and matte brownish, unlike the untreated samples, silver color and gloss. The hardness of the surface (top and sides) was 65% and even higher than the original hardness. The nitrided layer showed great uniformity in microstructure and thickness. It is concluded, therefore, that the unit was effective constructed for the purposes for which it was designed

Teste de condutividade elétrica em função do número de sementes e da quantidade de água para sementes de milheto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Método de preparo das sementes de mamoneira (Ricinus communis L.) para o teste de tetrazólio

O teste de tetrazólio é um método rápido e eficaz para avaliar a viabilidade e o vigor de sementes. O presente trabalho teve por objetivo padronizar o método de preparo das sementes de mamoneira (Ricinus communis L.) para a avaliação do potencial fisiológico pelo teste de tetrazólio. Foram testados os seguintes métodos de preparo das sementes: corte longitudinal mediano através do tegumento, endosperma e embrião; corte longitudinal diagonal sem atingir o eixo embrionário; remoção do tegumento; remoção do tegumento com corte longitudinal mediano através do endosperma e embrião; e remoção do tegumento com corte longitudinal mediano, paralelo aos cotilédones, através do endosperma e embrião. Antes dos preparos, as sementes foram pré-condicionadas entre papel toalha umedecido por 18 horas a 30ºC, e após os preparos, as sementes foram imersas na solução de tetrazólio na concentração de 0,5% e mantidas em câmara escura a 35ºC para o desenvolvimento da coloração. Avaliou-se a uniformidade da coloração das sementes após cada preparo, por meio da comparação entre eles. Para a avaliação do potencial fisiológico das sementes de mamoneira pelo teste de tetrazólio o método indicado de preparo é a remoção do tegumento, com posterior corte longitudinal e mediano, no sentido do comprimento, através do endosperma e embrião.

Concentração da solução de tetrazólio e período de coloração do teste para sementes de mamoneira

O objetivo do trabalho foi estudar a concentração da solução de tetrazólio e o período de coloração do teste para a avaliação do potencial fisiológico de sementes de mamoneira (Ricinus communis L.), padronizando a nomenclatura das cores observadas nas sementes após a coloração. Os tratamentos de concentração da solução de tetrazólio e períodos de coloração estudados foram: 0,075% e 0,1% por 120, 180 e 240 minutos, 0,2% por 60, 120 e 180 minutos, 0,5% por 60, 90 e 120 minutos e 1,0% por 30, 60 e 90 minutos. Os resultados foram comparados com os obtidos nos testes de germinação. A coloração das sementes após o teste de tetrazólio, em cada tratamento, foi avaliada mediante comparação com as fichas de cor do catálogo de Munsell, determinando-se a porcentagem de sementes observada em cada cor. O delineamento experimental foi o inteiramente casualizado e a comparação de médias realizada pelo teste de Tukey a 5% de probabilidade. Para avaliar o potencial fisiológico pelo teste de tetrazólio, as sementes de mamoneira devem ser imersas na solução de tetrazólio na concentração de 0,2% por 120 minutos, a 35ºC. Nesse tratamento, as sementes viáveis após a coloração na solução de tetrazólio apresentaram predominantemente as cores rosa e rosa-escuro em suas estruturas essenciais, portanto essas podem ser consideradas como as cores características para o teste de tetrazólio em sementes de mamoneira.