Preparo do solo e emissão de CO2, temperatura e umidade do solo em área canavieira

Soil tillage is one of the agricultural practices that may contribute to increase the loss of carbon through emission of CO2 (FCO2). The aim of this study was to investigate the effect of three soil tillage systems on FCO2, soil temperature and soil moisture in a sugarcane area under reform. The experimental area consisted of three tillage plots: conventional tillage (CT), conventional subsoiling (CS), and localized subsoiling (LS). FCO2, soil temperature and soil moisture were measured over a period of 17 days. FCO2 showed the highest value in CT (0.75 g CO2 m(-2) h(-1)). Soil temperature presented no significant difference (p > 0.05) between LS (26.2 degrees C) and CS (25.9 degrees C). Soil moisture was higher in LS (24%), followed by CS (21.8%) and CT (18.3%). A significant correlation (r = -0.71; p < 0.05) between FCO2 and soil temperature was observed only in CT. The conventional tillage presented a total emission (2,864.3 kg CO2 ha(-1)) higher than the emissions observed in CS (1,970.9 kg CO2 ha(-1)) and LS (1,707.7 kg CO2 ha(-1)). The conversion from CT to LS decreased soil CO2 emissions, reducing the contribution of agriculture in increasing the concentration of greenhouse gases in the atmosphere.

Baixa umidade do solo na eficácia de herbicidas aplicados em pré-emergência

The aim of this study was to evaluate the effect of low soil moisture on the efficacy of applying herbicides ametryn + clomazone, sulfentrazone and tebuthiuron in pre-emergence application submitted to simulated rainfalls at different time intervals after application in control of B. pilosa, C. echinatus and U. plantaginea plants. The experiment was carried out in pots with a capacity of 2.5 L in green-house conditions and experimental design was completely randomized with four replications, arranged in a 3x5 factorial (three herbicides and five rains intervals). The herbicides clomazone + ametryn (Sinerge EC) 5.0 L commercial product (cp) ha(-1), sulfentrazone (Boral 500 SC) 1.2 L cp ha(-1) and tebuthiuron (combine SC) 2.0 L cp ha(-1) were applied in pre-emergence and the precipitation of 20 mm were applied under de pots in five time intervals after the herbicide application (0h, 4h, 8h, 12h and 24hours). Visual evaluations of plants control that emerged plants were realized at 14 and 21 days after treatment application and the plant emergence percentage was calculated. The application of these three herbicides in dry soil then rain within 24 hours after application provided C. echinatus plants emergence, reduced B. pilosa emergency but in the end of the experiment effectively controlled these two species and U. plantaginea plants.

Avaliação do desgalhador florestal de discos em função de diferentes teores de umidade da madeira de eucalipto

Pós-graduação em Ciência Florestal - FCA

Efeito da umidade no esmalte dental na interação de dois sistemas de colagem ortodôntica

Objetivo: a proposta desse estudo foi avaliar, por meio de microscopia eletrônica de varredura (MEV), a interface adesiva após a descolagem de acessórios ortodônticos, fixados em dentes bovinos com emprego de adesivo hidrofílico e hidrofóbico, em condições distintas de umidade do substrato dentário. Métodos: foram utilizados 20 incisivos inferiores, divididos em quatro grupos (n = 5): Grupo I , empregou-se o sistema de colagem contendo o primer hidrofílico Transbond MIP e a pasta adesiva Transbond XT, aplicados em substrato úmido; Grupo II, empregou-se o sistema de colagem primer hidrofóbico Transbond XT e pasta adesiva em substrato úmido; Grupos III e IV, os braquetes foram colados com os mesmos sistemas de união dos Grupos I e II, porém com esmalte dentário seco. Removidos os acessórios, avaliou-se em MEV, em diferentes magnificações, a interface adesiva e a interação dos sistemas adesivos com o esmalte dentário. As imagens foram avaliadas qualitativamente, observando-se o embricamento mecânico para o adesivo hidrófilo em quaisquer condições de substrato. Resultados: a falta de umidade no esmalte condicionado permitiu uma melhor interação entre os materiais de ligação e a estrutura adamantina. O adesivo hidrofóbico apresentou o pior resultado de interação micromecânica quando aplicado a uma estrutura dentária úmida; já o sistema hidrofílico mostrou-se versátil, obtendo resultados aceitáveis em condições de umidade e excelente interação na ausência de contaminação. Conclusão: os autores afirmam que a melhor condição do esmalte dentário para a aplicação de primers é com a ausência de umidade.

Influência do manejo de residuos vegetais na umidade do solo e na produtividade do feijoeiro irrigado por pivô central

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Calibração de um equipamento TDR (Reflectometria por Dominio do Tempo) para a Determinação da Umidade da Madeira de Grevillea robusta (Cunn.)

This study aimed to establish a calibration model of a TDR equipment to determinate thewood moisture of Grevillea robusta (Cunn.). It was selected alleatory, 11 logs of Grevillea robusta (Cunn.), it was dried in a regulate electric greenhouse at 40o C. During the dry process, the moisture was determinate, periodically and systematically by gravimetric and TDR methods. Through the gravimetric method, moisture vary from 125,88% to 6,62% while the TDR method, the variation was from 119,83% to 5,79%. The best model adjusted to the wood moisture in the determination of the function of relative dielectric constant, using this technique, was the exponential 50,20 132,72 140,27 K U e − = − ⋅ , with a R2 = 0,96, with indicator of trust or performance 0,97 they were classified as very good, according to Camargo and Sentelhas (1997). The correlation between the gravimetric method (reference) and TDR, showed to be equivalent for both methodologies. It was concluded that the TDR can be used to the determination of wood moisture of Grevillea robusta (Cunn.), in a precise and fast way, once it was established it calibration.

Avaliação do efeito da inclinação e umidade antecedente na qualidade e quantidade das parcelas escoadas, percoladas e armazenadas em telhado verde extensivo

This study investigated the effect of slope and antecedent soil moisture on the water depth stored and percolated on extensive green roofs built in pilot scale. For this purpose, slopes of 10, 20 and 30% were investigated. Moisture was measured before and after each test in order to determine the differential moisture (∆U). The experimental runoff and percolated flow were analyzed by varying moisture and slope. Apparent color and turbidity were measured on runoff and percolated flow for each one of the modules. The results yielded that for the slopes of 10% the smaller values of runoff was obtained (average of 1,01% ± 0,7%). For the others slopes (20% and 30%), the runoffs were around 35% ± 15%. The sum of runoff and percolated water results in 77% (average) for slope of 10% and 80% for 20% and 30%. The slope and moisture have explained 87% of data for retained water and 81% for runoff. For percolated flow the inverse trend was observed. The retained water was 11,6±1,4mm for the module with 10% of slope, around 10,0±1,2 mm for the module with 20% of slope, and about 9,5±1,1 mm for the module with 30%. The results pointed out that both slope and antecedent moisture are crucial for runoff reduction and for material transportation.

Variabilidade espacial da umidade relativa do ar no interior de uma casa de vegetação em clima tropical

Greenhouse with natural ventilation is widely used in tropical countries, and little knowledge is available about how this type of structure affects the spatial variability of agroclimatic variables. The aim of this study was to analyse the spatial variability of relative humidity inside a greenhouse with natural ventilation. The measurement of relative humidity was done at 114 points inside the greenhouse at 9, 12 and 16 hours and on heights of 0.3, 1.2 and 2.0 m. The acquired data were processed by the geostatistical software GS+ and maps were generated and displayed for each time and height using the Surfer 10.3.705 software. The results showed that there were variations in the spatial distribution of relative humidity inside the greenhouse.

Umidade na folha de amoreira (Morus sp.) em ambientes de armazenamento

Mulberry leaves (IZ 56/4 cultivar) in the pos-harvest, had been taken to the laboratory and submitted to six storage environments (8 hours in open ambient-O, 8 hours in cover ambientC, 1hO/7hC, 2hO/6hC, 3hO/5hC and 4hO/4hC), aiming to evaluate moisture exchange capacity . It was utilized the experimental design split plot with five replications (blocks), six principal treatments (parcels) and nine secondary treatments (sub parcels, weighing of hour in hour, of 08h00min. until 16h00min.). In the period of eight hours of experimentation mulberry leaves moisturedevreased in all the ambients evaluated. However, for cover leaves with wet cloth, for all periods, the water purport (74,63%) was maintained close to the original value (08h00min.- 76,07%), demonstrating the efficiency technique in the conservation of the humidity of leaves for feeding silkworm.

Determinação de atividade de água, umidade e sal em peixes salgados e secos importados

Brazil is a major importer in the world salted fish trade. The sale of these products must meet the established standards, based mainly on the salt and moisture levels. The aim of this study was to analyze the salt and moisture levels in imported Atlantic cod and Pacific cod, and in the dried salted fish Ling, Zarbo and Saithe, which are not classified as cod since they do not belong to the genus Gadus. The water activity was also analyzed, which could be a useful parameter to determine the quality of salted fish.The results showed that the legal limits for salt were much lower than the values found in the analyses. The moisture contents established for the category of salted fish, as determined by the Portuguese legislation, were more reliable. We suggest the inclusion of the water activity as a parameter for the evaluation of these products.

Sistema de monitoramento da temperatura e umidade em silos graneleiros via radiofrequencia

The use of Information and Communication Technology has grown in most agricultural activities. As a consequence, it has changed the way of thinking and acting of the farmer who wants to establish a more and more competitive market. However, the high costs of acquisition and maintenance of those technologies may be a factor which can inhibit its spread and acceptance, mainly to a large number of small grain Brazilian farmers. In this context, there is a need for innovative solutions that are proper for this universe of farmers. Starting from this premise, this paper presents the development of a low cost prototype to the monitoring process of temperature and humidity values of grains stored in silos, using communication based on wireless technology by radio frequency. Therefore, the economic implications of cost/benefit ratio of innovative application of wireless transmission in the process of thermometry of grains were analysed. The prototype was made of two electronic units, one of acquisition and another one of data reception, as well as computational software, which offered the farmer more precise information for the control of aeration. By means of stability, integrity and reliability tests of data transmission via radio, using low cost electronic components, the development system can be considered as potentially viable. It presented the difference regarding the wireless communication via radio in the process of grains thermometry, providing mobility, reducing cabling costs and maintenance, and also offering an easy system expansion; it was also appropriate to temperature and humidity monitoring in grain silos; and revealed operational viability, besides the low cost development when compared to similar products available in the Brazilian market.

Umidificação e aquecimento do gás inalado em estação de anestesia com baixo fluxo de gases frescos com ou sem isolamento térmico do circuito ventilatório e com ou sem permutador de umidade e temperatura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Umidificação e aquecimento do gás inalado em estação de anestesia com baixo fluxo de gases frescos com ou sem isolamento térmico do circuito ventilatório e com ou sem permutador de umidade e temperatura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identificação e caracterização de ambientes homogêneos de eventos de seca/umidade com base em simulações climáticas regionais

O objetivo deste trabalho foi identificar e caracterizar ambientes homogêneos com base na ocorrência de eventos de seca/umidade na Região Centro-Norte do Brasil, compreendendo os Estados de Rondônia, Mato Grosso, Goiás e Tocantins. Para esse fim, utilizou-se o índice quantitativo de seca denominado Anomalia de Umidade de Palmer (Z-index). Os dados climáticos de entrada utilizados por esse índice para quantificar os eventos de seca/umidade foram simulados pelo modelo regional climático RegCM3 ("Regional ClimateModel - version3"), para o período de 1975 a 1989. Por meio de análise de agrupamento foram identificados 13 ambientes homogêneos. Esses ambientes homogêneos foram caracterizados por meio da probabilidade de ocorrência de eventos de seca/umidade, densidade relativa destes eventos, variabilidade da precipitação pluvial anual e a probabilidade de ocorrência de seca na época das águas (outubro a maio). No Estado do Mato Grosso observou-se o maior número de ambientes homogêneos e na Região Sudoeste desse Estado, o ambiente 11, obteve a maior probabilidade de ocorrência de eventos extremamente seco, 9%. O ambiente 10, localizado no extremo leste de Goiás, teve a menor mediana para a precipitação pluvial anual. O evento climático com maior probabilidade de ocorrência na região de estudo é o próximo ao normal ou normalidade de umidade.

Temperatura e umidade no armazenamento de materiais autoclavados: revisão integrativa

São diversificadas as recomendações referentes à temperatura (T°) e umidade relativa do ar (UR) no armazenamento de materiais esterilizados em Centrais de Material e Esterilização (CME), sem que essas recomendações estejam embasadas em referenciais teóricos ou experimentos. A prática mostra dificuldades em controlar esses parâmetros, suscitando dúvidas quanto ao risco para a manutenção da esterilidade dos materiais. Este artigo propôs, por meio de uma revisão bibliográfica integrativa, identificar e analisar as recomendações referentes à T° e UR indicadas para o setor de guarda dos materiais na CME. Não foi encontrada literatura que justifique tais recomendações. Foram incluídas sete publicações que analisaram as variáveis T° e UR da área de armazenagem como fatores que podem afetar a manutenção do material esterilizado, e apresentaram resultados contraditórios quanto à interferência desses fatores na manutenção da esterilidade dos materiais.