bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulador de Oscilações Mecânicas
Authors: Silva Adilson Costa da , Helayël Neto José Abdalla
Published: June 2016

Recentemente desenvolvemos um software com o objetivo de proporcionar uma visão do fenômeno físico, sem a necessidade de conhecer a equação que descreve o movimento. Desta forma, este simulador visa ilustrar o comportamento das variáveis de interesse, tais como, posição, velocidade, aceleração e energia evoluindo no tempo. Neste artigo, apresentamos soluções analíticas para cada caso de interesse, bem como, soluções numéricas usando o método de diferenças finitas. Um oscilador harmônico representa um sistema em movimento a ser repetido ao longo do tempo, isto é, move-se de uma posição inicial até outra posição, em torno de uma posição de equilíbrio. Desta forma, apresentaremos uma visão geral do problema a ser resolvido e os casos mais simples serão obtidos por simplificações deste problema. Como um dos objetivos deste artigo é incentivar os leitores a utilizarem métodos numéricos de soluções aplicados à física, logo, abordamos de forma bastante simples a solução numérica do oscilador mecânico. Avaliamos também o comportamento da energia e verificamos sob quais condições ela é conservada. Para validar o método numérico implementado neste artigo, comparamos os resultados obtidos pela solução numérica com os resultados obtidos pela solução analítica usada neste artigo.
The problem of the electrical discharge in an internally wired capacitor
Authors: Rizzato F. B.
Published: June 2016

The present work investigates the dynamics of electrical discharges in a capacitor where both plates are internally connected by a conducting wire. A simplifying assumption used to solve the problem is to consider a uniform distribution of the surface charges on the plates. This implies uniform electric fields as well, and allows to calculate the current in the wire as if it were flowing along a simple RC circuit. We show that although the assumption is good if the conductivity of the wire is small, it fails if the conductivity becomes larger than a critical value. The device's behavior beyond this critical value is then analyzed and discussed. The relevance of the problem is discussed in connection to solid-state devices, as well as in problem solving contexts.
Organic compost and wastewater on the initial growth of oilseed plants
Authors: Pereira Júlia S. , Guimarães Jean P. , Lopes Riuzuani M. B. P. , Farias Maria S. S. de , Lima Vera L. A. de , Azevedo Carlos A. V. de
Published: June 2016

ABSTRACT The study was conducted in two experiments in greenhouse of the CTRN/UFCG, aiming to evaluate the use of organic compost from household garbage and irrigation with treated domestic wastewater on the growth of castor bean 'BRS-188/Paraguaçu' and sunflower 'Embrapa 122-V2000'. Both experiments were conducted a randomized block design in 6 x 2 factorial scheme, with three replicates, which corresponded to six doses of organic compost (0, 1.2, 2.0, 2.8, 3.6 and 4.4 kg pot-1, equivalent to 0, 60, 100, 140, 180 and 220 kg N ha-1) and two types of water (freshwater and wastewater). It was found that the organic compost doses significantly influenced the growth of sunflower and castor bean in all evaluations, except for stem diameter. The maximum plant heights were 91.7 cm for castor bean and 85.2 cm for sunflower at the doses of 180 and 220 kg N ha-1, respectively. The highest values of number of leaves were obtained for the N dose of 220 kg ha-1 in both crops. The influence of wastewater on growth variables was only observed in the final evaluations, for both sunflower and castor bean.
Artificial neural networks employment in the prediction of evapotranspiration of greenhouse-grown sweet pepper
Authors: Pandorfi Héliton , Bezerra Alan C. , Atarassi Roberto T. , Vieira Frederico M. C. , Barbosa Filho José A. D. , Guiselini Cristiane
Published: June 2016

ABSTRACT This study aimed to investigate the applicability of artificial neural networks (ANNs) in the prediction of evapotranspiration of sweet pepper cultivated in a greenhouse. The used data encompass the second crop cycle, from September 2013 to February 2014, constituting 135 days of daily meteorological data, referring to the following variables: temperature and relative air humidity, wind speed and solar radiation (input variables), as well as evapotranspiration (output variable), determined using data obtained by load-cell weighing lysimeter. The recorded data were divided into three sets for training, testing and validation. The ANN learning model recognized the evapotranspiration patterns with acceptable accuracy, with mean square error of 0.005, in comparison to the data recorded in the lysimeter, with coefficient of determination of 0.87, demonstrating the best approximation for the 4-21-1 network architecture, with multilayers, error back-propagation learning algorithm and learning rate of 0.01.
Modeling of soil water infiltration with rainfall simulator in different agricultural systems
Authors: Santos Thais E. M. dos , Souza Edivan R. de , Montenegro Abelardo A. A.
Published: June 2016

ABSTRACT This study aimed to compare models for predicting soil water infiltration rate and erosive rates using a rainfall simulator in different systems of common bean (Phaseolus vulgaris L.) cultivation. The evaluated mathematical models were: Kostiakov, Kostiakov-Lewis, Green-Ampt and Horton. Infiltration tests were carried out considering six treatments: bean cultivated on contour with rock barriers spaced at 0.5 m between crop rows (BC1); bean cultivated on contour with rock barriers spaced at 1.0 m between crop rows (BC2); bean cultivated downslope (BDS); bean cultivated on contour with mulch (BCM); bare soil (BS) and soil under natural cover (NC). Four replicates were considered, totaling 24 field tests. Kostiakov-Lewis's equation showed the lowest values of standard error. Soil water infiltration rate was equal to 53.3 mm h-1 in the natural vegetation treatment and to 9.49 mm h-1 in the downslope treatment. Surface roughness and the time of beginning of surface runoff were significantly higher for the conditions with mulch cover.
Growth of young Tabebuia aurea seedlings under irrigation with wastewater from fish farming
Authors: Pinto José R. de S. , Freitas Rômulo M. O. de , Leite Tiago de S. , Oliveira Francisco de A. de , Ferreira Hugo , Leite Moadir de S.
Published: June 2016

ABSTRACT This study aimed to evaluate the growth of young Tabebuia aurea seedlings irrigated with different concentrations of wastewater from fish farming. The experiment was conducted in a seedling nursery, from June to August 2013. The treatments consisted of five concentrations of wastewater from fish farming diluted in freshwater (0, 25, 50, 75 and 100% of wastewater). Plant height, stem diameter and plant height/stem diameter ratio were evaluated every 15 days to verify the effects of treatments on seedlings growth. At the end of the experiment, individual leaf area, leaf area, leaf dry matter, stem dry matter, root dry matter, total dry matter and Dickson quality index were also evaluated. The reuse of wastewater from fish farming diluted at concentrations of 25 and 50% in freshwater is a viable alternative in the production of Tabebuia aurea seedlings. However, higher concentrations hinder the production of seedlings of this species.
Gas exchange and leaf contents in bell pepper under energized water and biofertilizer doses
Authors: Borges Francisca R. M. , Viana Thales V. de A. , Marinho Albanise B. , Pinheiro Neto Luis G. , Azevedo Benito M. de
Published: June 2016

ABSTRACT The objective of this study was to evaluate the effect of energized water and bovine biofertilizer doses on the gas exchange and NPK contents in leaves of yellow bell pepper plants. The experiment was conducted at the experimental area of the Federal University of Ceará, in Fortaleza-CE, Brazil, from June to November 2011. The experiment was set in a randomized block design, in a split-plot scheme; the plots were composed of treatments with energized and non-energized water and the subplots of five doses of liquid biofertilizer (0, 250, 500, 750 and 1000 mL plant-1 week-1). The following variables were analyzed: transpiration, stomatal conductance, photosynthesis and leaf contents of nitrogen (N), phosphorus (P) and potassium (K). Water energization did not allow significant increases in the analyzed variables. The use of biofertilizer as the only source of fertilization was sufficient to provide the nutrients N, P and K at appropriate levels for the bell pepper crop.
Pasture production under different irrigation depths
Authors: Antoniel Laísa S. , Prado Giuliani do , Tinos Adriano C. , Beltrame Gabriel A. , Almeida João V. C. de , Cuco Gustavo P.
Published: June 2016

ABSTRACT This study aimed to evaluate the production of two pasture species, Brachiaria brizantha cv. BRS Piatã and Panicum maximum cv. Mombaça, under different irrigation depths. The experiment was carried out from May to December 2014, at the State University of Maringá, in the municipality of Cidade Gaúcha-PR, Brazil. The experiment was set out in a strip-plot design, with four replicates, six irrigation depths in the plot and two pasture species in the subplot. Irrigation depths were represented by a percentage of reference evapotranspiration (ET0), which was estimated by the Penman-Monteith equation. Four pasture cuts were performed during the studied period and there were no differences between the yields of both evaluated pasture species; however, irrigation depths caused a quadratic response on pasture yield. The maximum values of dry matter yield of the pastures under irrigated conditions were 52.1, 41.6, 26.2 and 25.1% higher than under non-irrigated conditions, for the 1st, 2nd, 3rd and 4th cuts, respectively. Irrigation depths that applied water volumes close to ET0 promoted considerable increases in pasture yield.
Yield and vegetative growth of cactus pear at different spacings and under chemical fertilizations
Authors: Silva João A. da , Donato Sérgio L. R. , Donato Paulo E. R. , Souza Evilasio dos S. , Padilha Júnior Milton C. , Silva Junior Ancilon A. e
Published: June 2016

ABSTRACT The objective was to evaluate the effect of different spacings and mineral fertilizations on cactus pear growth and production in a randomized block design, with three replicates, in a 3 x 4 factorial scheme: three spacings, 1.00 x 0.50 m, 2.00 x 0.25 m and 3.00 x 1.00 x 0.25 m, and four fertilizations, 000-000-000, 000-150-000, 200-150-000 and 200-150-100 kg ha-1 of N, P2O5 and K2O, respectively. Plant growth was evaluated between 90 and 390 days and production and growth were evaluated at 620 days after planting. There were significant interactions between spacing and fertilization for plant height, number of cladodes and cladode area index from 90 to 390 days and for production of fresh and dry matter at 620 days after planting. Spacing influenced cladode area index, while fertilization influenced plant height, number of cladodes and cladode area index at 620 days after planting. Plant height showed cubic effect for the days after planting. Number of cladodes and cladode area index were dependent on spacing, fertilization and plant age, and fitted to cubic models. The best results of growth and production of fresh and dry matter are associated with NPK and NP fertilizations and the spacing of 1.00 x 0.50 m.
Spatial variability of enthalpy in broiler house during the heating phase
Authors: Ferraz Patrícia F. P. , Yanagi Junior Tadayuki , Ferraz Gabriel A. e S. , Schiassi Leonardo , Campos Alessandro T.
Published: June 2016

ABSTRACT The thermal environment inside a broiler house has a great influence on animal welfare and productivity during the production phase. Enthalpy is a thermodynamic property that has been proposed to evaluate the internal broiler house environment, for being an indicator of the amount of energy contained in a mixture of water vapor and dry air. Therefore, this study aimed to characterize the spatial variability of enthalpy in a broiler house during the heating phase using geostatistics. The experiment was conducted in the spring season, in a commercial broiler house with heating system consisting of two furnaces that heat the air indirectly, in the first 14 days of the birds' life. It was possible to characterize enthalpy variability using geostatistical techniques, which allowed observing the spatial dependence through kriging maps. The analyses of the maps allowed observing problems in the heating system in regions inside the broiler house, which may cause a thermal discomfort to the animals besides productive and economic losses.
Mathematical modeling and determination of thermodynamic properties of jabuticaba peel during the drying process
Authors: Costa Cristian F. , Corrêa Paulo C. , Vanegas Jaime D. B. , Baptestini Fernanda M. , Campos Renata C. , Fernandes Lara S.
Published: June 2016

ABSTRACT Jabuticaba is a fruit native of Brazil and, besides containing many nutritional qualities, it also has a good field for use in products such as flour for cakes and biscuits, juice, liqueur, jelly and others. This study aimed to model the drying kinetics and determine the thermodynamic properties of jabuticaba peel at different drying air temperatures. Ripe fruits of jabuticaba (Myrciaria jaboticaba) were collected and pulped manually. Drying was carried out in a forced-air circulation oven with a flow of 5.6 m s-1 at temperatures of 40, 50, 60 and 70 °C. Six mathematical models commonly used to represent the drying process of agricultural products were fitted to the experimental data. The Arrhenius model was used to represent the drying constant as a function of temperature. The Midilli model showed the best fit to the experimental data of drying. The drying constant increased with the increment in drying temperature and promoted an activation energy of 37.29 kJ mol-1. Enthalpy and Gibbs free energy decreased with the increase in drying temperature, while entropy decreased and was negative.
Preservation of roasted and ground coffee during storage Part 1: Moisture content and repose angle
Authors: Corrêa Paulo C. , Oliveira Gabriel H. H. de , Oliveira Ana P. L. R. de , Vargas-Elías Guillermo A. , Santos Fábio L. , Baptestini Fernanda M.
Published: June 2016

ABSTRACT The present study evaluates the influence of the level of roasting and the grind size on the moisture content and repose angle of coffee during storage. Raw coffee beans (Coffea canephora and Coffea arabica), hulled and dried, were roasted to two different levels: medium light (SCAA#65) and moderately dark (SCAA#45). The beans were then ground into three different grind sizes: fine (0.59 mm), medium (0.84 mm) and coarse (1.19 mm). An additional coffee lot was kept whole. Following grinding, samples were stored at two different temperatures (10 and 30 ºC) and analyzed after five different storage durations (0, 30, 60, 120 and 180 days). The moderately dark roast was found to have a lower moisture content. Finely ground samples had higher angles of repose. It is concluded that the grind size, level of roasting and duration of storage significantly affect the moisture content and angle of repose of coffee.
Fuel consumption of a sugarcane harvester in different operational settings
Authors: Ramos Carlos R. G. , Lanças Kléber P. , Lyra Gabriel A. de , Sandi Jefferson
Published: June 2016

ABSTRACT The interventions performed during the mechanized harvesting are essential to improve the operational performance of sugarcane harvesters and reduce operational costs. The objective of the present study was to evaluate the fuel consumption of a sugarcane harvester in different forward speeds and engine rotations. Harvesting was conducted in a green cane plot, with the variety RB 855156. Flow meters were installed in the harvester's fuel supply system and an electronic device was used for data acquisition. The experiment was carried out in a completely randomized design in a factorial scheme (3 x 2), using three engine rotations and two forward speeds, with six replicates. Harvesting capacity and fuel consumption per hour, per area and per ton of harvested sugarcane were analyzed. The results were subjected to analysis of variance and means were compared by Tukey test. The variations in engine rotation did not affect the performance for harvesting capacity, but influenced fuel consumption. Forward speed influenced both harvesting capacity and fuel consumption.
The effects of irrigation management on floral induction of ‘Tommy Atkins' mango in bahia semiarid
Authors: Faria Leandro N. , Soares In memoriam Antônio A. , Donato Sérgio L. R. , Santos Marcelo R. dos , Castro Luciana G.
Published: June 2016

ABSTRACT This study aimed to evaluate reduction strategies of irrigation for proper management of floral induction and production of 'Tommy Atkins' mangoes, in the semiarid region of the Bahia state, Brazil. Five treatments with reduced irrigation levels based on crop evapotranspiration (ETc) were applied in two development stages, FI - flowering and FII – fruiting. Water depths were T1 - 0% of ETc in FI and 100% in FII; T2 - 25% of ETc in FI and 100% in FII; T3 - 50% of ETc in FI and 100% in FII; T4 - 75% of ETc in FI and 100% in FII; and T5 - 100% of ETc in FI and FII. The treatments were arranged in a randomized complete block design with six replications. Photosynthesis and transpiration rates in phases FI and FII were larger at 8 am than at 2 pm, regardless of the strategies used. These strategies lead to smaller values of photosynthesis, transpiration and leaf water potential within flowering stage. Productive characteristics were not affected by irrigation level reduction for flower induction process, only for the cycles evaluated. Strategies with 0% of ETc in FI and 100% in FII or 25% of ETc in FI and 100% in FII are appropriate to flower induction in 'Tommy Atkins' mango.
Anaerobic biodigestion of manure from finishing pig supplemented with ractopamine over different periods
Authors: Santos Tânia M. B. dos , Trevizan Paula S. F. , Xavier Cristiane A. N. , Kiefer Charles , Ferraz André L. J.
Published: June 2016

ABSTRACT This study aimed to evaluate the efficiency of anaerobic digestion and biogas production by manure from pig supplemented with ractopamine over different periods. We used manure of 50 finishing pigs according to the following diets: without supplementation and supplemented with 20-ppm ractopamine during 7, 14, 21, 28 and 35 days pre-slaughter. Continuous bench biodigesters were used in the experiment. We measured biogas production and made analyses of total (TS) and volatile solids (VS), pH, total phosphorus (total P), total nitrogen (total N) and ammoniacal nitrogen (ammoniacal N) in samples of manure, affluent and effluent from biodigesters. The pH and ammoniacal N as indicator parameters of the process balance and stability were satisfactory. Moreover, there was no difference in the reduction of TS and VS (50.04 and 56.51%, respectively). Manure of animals supplemented with ractopamine for 35 and 28 days presented higher biogas production (0.0722 and 0.0603 m3 kg−1, respectively). The supplementation with 20-ppm ractopamine for finishing pigs from 7 to 35 days does not present collapse risks for the anaerobic biodigestion process.
Diagnóstico energético de rotas de escoamento do etanol da região Centro-Oeste do Brasil para exportação
Authors: Bovolenta Fábio C. , Biaggioni Marco A. M.
Published: June 2016

RESUMO O grande desafio para o agronegócio nos próximos anos é a infraestrutura logística, uma vez que existem muitas dificuldades em escoar a produção. Para o escoamento do etanol, o País possui uma logística que abrange multimodais de transporte, terminais e vias que visam a fortalecer o corredor exportador. Assim, o presente trabalho analisou o fluxo energético, considerando rotas atualmente projetadas, em construção ou operantes, para o escoamento de etanol da região Centro-Oeste do Brasil (Aparecida do Taboado-MS) até o porto de São Sebastião (SP). Foram concebidas quatro rotas para a análise, contemplando a multimodalidade ou a unimodalidade, envolvendo os modais rodoviário, ferroviário, hidroviário e dutoviário. Foram utilizados fatores energéticos, diretos e indiretos, envolvidos nas operações, para contabilizar os inputs e outputs do sistema: óleo diesel, energia indireta de máquinas e equipamentos, energia de mão de obra, energia elétrica, além da depreciação energética e da manutenção das vias. Os resultados obtidos indicaram o modal dutoviário como o que menos despendeu energia e o modal rodoviário o de maior demanda energética. Os modais hidroviário e ferroviário também se apresentaram energeticamente viáveis, em comparação ao modal rodoviário.
Produção e pós-colheita de flores de girassóis sob estresse salino em hidroponia de baixo custo
Authors: Santos Júnior José A. , Gheyi Hans R. , Cavalcante Antônio R. , Dias Nildo da S. , Medeiros Salomão de S.
Published: June 2016

RESUMO Em face de características relacionadas à infraestrutura, situação edáfica, hídrica e social, peculiares do semiárido brasileiro, é precípua a utilização de sistemas de cultivo alternativos que considerem tais características, inclusive a qualidade da água disponível. Dentro desta lógica, o objetivo do presente trabalho foi avaliar os efeitos do estresse salino sobre as variáveis de produção e pós-colheita de flores de girassóis cultivadas em um sistema hidropônico alternativo de baixo custo. Utilizou-se de delineamento experimental inteiramente casualizado, analisado em esquema fatorial 4 x 3, com três repetições; os tratamentos consistiram na utilização de quatro níveis de salinidade da solução nutritiva (1,7 – testemunha; 4,3; 6,0 e 9,0 dS m-1) na produção de três cultivares de girassol (sol noturno, bonito de outono e anão de jardim). Verificou-se que, mesmo sob efeito da salinidade da solução nutritiva até o nível de 9 dS m-1, o número de pétalas e a duração pós-colheita mantiveram-se dentro dos padrões comerciais para as cultivares “Sol-Noturno” e “Anão-de-Jardim”.
Modeling and correction of soil penetration resistance for variations in soil moisture and soil bulk density
Authors: Silva Wininton M. da , Bianchini Aloísio , Cunha Cesar A. da
Published: June 2016

ABSTRACT This study aimed to describe the behavior of models for adjusting data of soil penetration resistance for variations in soil moisture and soil bulk density. The study was carried out in Lucas do Rio Verde, MT, Brazil in a typic dystrophic red-yellow Latosol (Oxisol) containing 0.366 kg kg−1 of clay. Soil penetration resistance measurements were conducted in the soil moistures of 0.33 kg kg−1, 0.28 kg kg−1, 0.25 kg kg−1 and 0.22 kg kg−1. Soil penetration resistance behavior due to variations in soil moisture and soil bulk density was assessed by estimating the soil resistance values by non-linear models. There was an increase of the soil penetration resistance values as soil was losing moisture. For the same edaphic condition studied, small differences in the data of soil bulk density affect differently the response of soil resistance as a function of moisture. Both soil bulk density and soil moisture are essential attributes to explain the variations in soil penetration resistance in the field. The good representation of the critical soil bulk density curve as a limiting compression indicator requires the proper choice of the restrictive soil resistance value for each crop.
Economic feasibility of irrigation systems in broccoli crop
Authors: Oliveira Fabricio C. de , Geisenhoff Luciano O. , Almeida Alexsandro C. dos S , Lima Junior Joaquim A. de , Lavanholi Rogério
Published: June 2016

ABSTRACT This study aimed to analyze the economic feasibility of different irrigation systems in broccoli cropping, in Dourados - MS, Brazil. Initially, irrigation was performed using different systems (surface drip, subsurface drip, micro sprinkler, Santeno® and conventional sprinkler). Both yield of commercial inflorescence (CIY) and applied water depth (AWD) were determined during trial. Economic feasibility was analyzed through estimates of acquisition cost (AC), total annual cost (TAC), gross revenue (GR), net revenue (NR), benefit-cost rate (BCR), return rate (RR) and return time (RT). Subsurface drip irrigation was the most feasible in addition to using the second lowest AWD (170.3 mm) compared to the other systems. The values of CIY, AC, RR, BCR and TAC obtained by this system were 25.3 t ha-1, R $ 8,884.8 ha-1, R $ 65,446.9 ha-1 yr-1, 7.3 and 6.32%, respectively.
Intensity-Duration-Frequency relationships: stochastic modeling and disaggregation of daily rainfall in the lagoa Mirim watershed, Rio Grande do Sul, Brazil
Authors: Damé Rita de C. F , Teixeira-Gandra Claudia F. A. , Guedes Hugo A. S. , Silva Gisele M. da , Silveira Suélen C. R. da
Published: June 2016

ABSTRACT This study aimed to investigate information gain by using rainfall intensity-duration-frequency (IDF) relationships, with data gathered within N+M years from seven rain gauge stations located in the Lagoa Mirim Watershed (South Atlantic basin). After N years of daily rainfall, the transition probabilities of a time homogeneous two-state Markov chain were defined to simulate rainfall occurrence, as well as gamma distribution to measure it; for that, daily rainfall series were composed of N+M years, with M being the generated series. The series were adjusted to Gumbel distribution, being used in annual maximum daily rainfall disaggregation for durations of 10, 20, 30, 40, 50, 60, 120, 360, 720 and 1440 min. Daily rainfall disaggregation was validated through IDF relationships taken from pluviograph records of N years and from N+M years, using the “t” test of relative mean squared error. We can infer that there was information gain using IDF relationships of rainfall occurrence when using N years of observed data and M years of generated data by stochastic modeling compared to those obtained from a composed series of N years.
Corn yield under various simulated irrigation depths
Authors: Parizi Ana R. C. , Robaina Adroaldo D. , Gomes Ana C. dos S. , Peiter Marcia X. , Soares Fátima C.
Published: June 2016

ABSTRACT Mathematical models are tools to estimate and understand system behaviors against diverse situations; they may help in decision-making through simplified representations of the reality, allowing simulating various scenarios and estimating impacts of different courses of action on production systems, assisting thus in activity planning. Thus, this paper proposed a simulation of corn crop yields according to different field experiment characteristics and weather conditions in which it was conducted, with the purpose of setting a simulation model already calibrated and tested for corn crop cycle in the region of Santiago – RS, Brazil. The increasing water levels had a positive effect on grain yield and corn dry matter. On the other hand, a level of 800 mm reduced corn yield, as well as water application efficiency decreased from 550 mm. The proposed model can be used as a tool for regional planning in corn crop implementation under irrigation and enables identifying irrigation strategies for high grain yields, being considered a tool for yield prediction in irrigated crops.
Higroscopicidade das sementes de sorgo-sacarino
Authors: Ullmann Renan , Resende Osvaldo , Oliveira Daniel E. C. , Costa Lílian M. , Chaves Tarcísio H.
Published: June 2016

RESUMO Objetivou-se, neste trabalho, determinar as isotermas de dessorção das sementes de sorgo-sacarino para diversas condições de temperatura e atividades de água e obter o calor isostérico de dessorção. As sementes foram submetidas à secagem em estufa com ventilação de ar forçada a 40 °C até atingir os teores de água de aproximadamente 24; 19; 15; 12 e 8 (% b.s.). As isotermas de dessorção das sementes de sorgo-sacarino foram obtidas pelo método estático indireto, sendo a atividade de água (aw) determinada por meio do equipamento Hygropalm Model Aw 1. Para o controle da temperatura, utilizou-se de B.O.D., regulada a 10; 20; 30 e 40 °C. Aos dados experimentais, foram ajustados modelos matemáticos frequentemente utilizados para a representação da higroscopicidade de produtos vegetais. Verificou-se que o modelo de Chung-pfost é o que melhor representa a higroscopicidade das sementes de sorgo-sacarino. O calor isostérico integral de dessorção aumenta com a redução do teor de água, sendo que os valores, para as sementes de sorgo-sacarino na faixa de teor de água de 7,9 a 28,0 (% b.s.), variam de 3.136,54 a 2.493,33 kJ.kg-1.
Codigestão anaeróbia dos dejetos de bovinos leiteiros e óleo de descarte
Authors: Orrico Ana C. A. , Lopes Walter R. T. , Manarelli Débora M. , Orrico Junior Marco A. P , Sunada Natália da S
Published: June 2016

RESUMO Este trabalho foi realizado com o intuito de se avaliarem a codigestão dos dejetos de bovinos leiteiros e óleo de descarte, por meio das produções específicas de biogás, reduções dos teores de sólidos totais (ST) e voláteis (SV), da demanda química de oxigênio (DQO) e fibra em detergente neutro (FDN). Utilizaram-se 28 biodigestores batelada, abastecidos com substratos contendo 4% de ST e compostos por dejetos de bovinos leiteiros, óleo de descarte (nas doses de 0; 2; 4; 6; 8; 10 e 12% dos STs do substrato e representado pelo resíduo de frituras que foi doado por pastelaria), inóculo e água para diluição. As máximas reduções de SV, DQO e FDN, além das produções específicas de biogás, foram obtidas por modelos quadráticos de predição, estimando-se, assim, as doses ideais de inclusão de óleo. As maiores reduções de DQO, SV e FDN foram de 82,88; 47,53; 51,28 e 49,48%, alcançadas com as inclusões de 5,74; 5,93, 4,77 e 6,45% de óleo de descarte, respectivamente. A inclusão de 4,63% de óleo permitiu alcançar a produção de 0,25 litro de biogás por g SV adicionado, que foi superior em 13% ao rendimento observado nos substratos sem inclusão de óleo. A adição de óleo em substratos contendo dejetos de bovinos leiteiros nas doses entre 4,4 e 6,5% aumenta as produções de biogás e as reduções de sólidos.
Homogeneous Pinus sp. particle boards reinforced with laminated composite materials
Authors: Christoforo André L. , Nascimento Maria F. do , Panzera Tulio H. , Ribeiro Filho Sérgio L. M , Lahr Francisco A. R.
Published: June 2016

ABSTRACT This study aimed to evaluate the mechanical performance of laminated composite materials (fiberglass, carbon, sisal, palm fiber) in epoxy matrix as reinforcement in wood particleboards of Pinus sp. with bicomponent polyurethane resin from castor oil. Modulus of elasticity (MOE) and modulus of rupture (MOR) were investigated using a three-point bending test. Single-layered laminated plates were used to reinforce traction of specimens obtained from boards. MOE and MOR of materials developed without reinforcements exceeded limits in ABNT standards both NBR 12810-2:2002 and A208.1:199, proving therefore their feasibility. In all investigated cases, inclusion of reinforcements led to higher values for both MOE and MOR. Composites in fiberglass presented the best results.
Elasticity moduli in round wooden beams of Pinus caribaea
Authors: Zangiácomo André L. , Christoforo André L. , Lahr Francisco A. R.
Published: June 2016

ABSTRACT This research aimed at estimating both longitudinal (E) and shear (G) elasticity moduli of round structural-sized beams made of Pinus caribaea timber, verifying thus the validity of the G = E/ 20 relationship established by the Brazilian standard ABNT NBR 7190: 1997 (Designing of Wooden Structures). We tested twenty pieces of green wood with average length, diameter and conicity of 750 cm, 30 cm and 4%, respectively. Two static bending tests were applied at three points of each piece, being nondestructive and using different distances between supports. In the first trial, the length and diameter relationship (L/ d) was set as being equal to 24; yet in the second test, it was set at 12. The elasticity moduli were estimated by a successive use of the Timoshenko beam theory equation, which takes into account the shearing stress effect on displacement calculations. The results of both longitudinal and shear moduli were related through the least square assessment method; thus, we could find a relationship of G = E/ 43. As a result, we observed that the tested wooden pieces are at odds with the Brazilian standards.
SOIL CHEMICAL ATTRIBUTES AND LEAF NUTRIENTS OF 'PACOVAN' BANANA UNDER TWO COVER CROPS
Authors: FLORI JOSÉ EGÍDIO , RESENDE GERALDO MILANEZ DE
Published: June 2016

ABSTRACT: Banana is one of the most consumed fruits in the world, which is grown in most tropical countries. The objective of this work was to evaluate the main attributes of soil fertility in a banana crop under two cover crops and two root development locations. The work was conducted in Curaçá, BA, Brazil, between October 2011 and May 2013, using a randomized block design in split plot with five repetitions. Two cover crops were assessed in the plots, the cover 1 consisting of Pueraria phaseoloides, and the cover 2 consisting of a crop mix with Sorghum bicolor, Ricinus communis L., Canavalia ensiformis, Mucuna aterrima and Zea mays, and two soil sampling locations in the subplots, between plants in the banana rows (location 1) and between the banana rows (location 2). There were significant and independent effects for the cover crop and sampling location factors for the variables organic matter, Ca and P, and significant effects for the interaction between cover crops and sampling locations for the variables potassium, magnesium and total exchangeable bases. The cover crop mix and the between-row location presented the highest organic matter content. Potassium was the nutrient with the highest negative variation from the initial content and its leaf content was below the reference value, however not reducing the crop yield. The banana crop associated with crop cover using the crop mix provided greater availability of nutrients in the soil compared to the coverage with tropical kudzu.
EVALUATION OF THE REACTION OF WATERMELON PARENT AND F 1 PLANTS TO Meloidogyne enterolobii
Authors: DAMACENO LÉIA SANTOS , QUEIROZ MANOEL ABÍLIO DE , DIAS RITA DE CÁSSIA SOUZA , CASTRO JOSÉ MAURO DA CUNHA E , TEIXEIRA FÁTIMA ALVES
Published: June 2016

ABSTRACT: The aim of this study was to evaluate the performance of progenies from Citrullus lanatus var. lanatus (cultivated watermelons) when crossed with progenies from C. lanatus var. citroides (fodder watermelon with a historic of resistance to the nematode Meloidogyne enterolobii). The parents and their F1s were evaluated for resistance to this nematode. In the initial stages of eleven treatments, watermelon seedlings plantlets were transplanted to plastic bags of six kilograms once the first leaves developed. Ten inoculated plants with 5,200 eggs in the soil near the stem of the plant and four non-inoculated ones were used in each treatment, in a complete block design. Sixty-two days after sowing, the following characteristics were evaluated: the length of the aerial part of the plant (LAP, in m), fresh mass of the aerial part (FMAP, in g), root fresh mass (RFM, in g), egg number (EN) and reproduction factor (RF). A comparison between the averages of inoculated and non-inoculated plants was performed using Scott-Knott test at 5% and the diallelic analysis was performed using the GENES program. The morphological characteristics did not allow for the identification of the parent plants or the F1s with respect to nematode resistance, but the variables EN and RF were useful for such identification. The analyses of the general and specific combining abilities indicate highly significant effects with respect to this resistance, showing additive gene effects as well as dominance and epistatic gene effects, allowing for identification of parents and F1s that can be used in watermelon breeding programs to improve resistance to the M. enterolobii.
MORPHOPHYSIOLOGICAL ANALYSIS OF PASSION FRUIT PLANTS FROM DIFFERENT PROPAGATION METHODS AND PLANTING SPACING
Authors: SANTOS JERFFSON LUCAS , MATSUMOTO SYLVANA NAOMI , OLIVEIRA PERLA NOVAIS DE , OLIVEIRA LUAN SANTOS DE , SILVA RICARDO DE ANDRADE
Published: June 2016

ABSTRACT: The passion fruit (Passiflora cincinnata Mast.) is a perennial and drought resistant species that represents a new alternative crop for small farmers in rainfed conditions. This study aimed to evaluate the vegetative and physiological development of passion fruit plants derived from two propagation methods and grown at varied planting spacing. The experiment was conducted from January to June of 2012, in the Universidade Estadual do Sudoeste da Bahia (State University from Southwestern Bahia), in Brazil. It was carried out in a randomized block design under a 2 x 3 factorial scheme, which consisted of two propagation methods (cutting and seeds) and three planting spacing distances within a row (1.5; 3.0 and 4.0 m), however, at same distance between rows (3.0 m), with four replicates and four plants per plot. Cuttings and seeds were sampled from adult plants pre-selected in native areas from Vitória da Conquista - BA, Brazil. Growth (stem diameter and leaf area) and physiological parameters (leaf chlorophyll content, leaf water potential before dawn, relative water content and leaf gas exchange) were assessed on the 90th, 120th and 150th day after transplanting of seedlings into the field (DAT). Based on our results, we concluded that despite plants propagated via cuttings showed most favorable water status, vegetative growth and photosynthetic capacity were lower whether compared to plants obtained from seeds.
CHAMOMILE PRODUCTION USING SUPPLEMENTARY IRRIGATION AND ORGANIC FERTILIZATION IN SANDY SOILS
Authors: ALEMAN CATARINY CABRAL , MARQUES PATRICIA ANGÉLICA ALVES , PACHECO ANA CLAUDIA
Published: June 2016

ABSTRACT: The use of medicinal plants in the herbal medicine of Brazilian Health System has intensified production and the need for developing efficient agricultural techniques that promote greater productivity of these species. The objective of this work was to evaluate the chamomile production at field conditions as a function of irrigation depths and organic fertilizer rates. The experiment was conducted in the Universidade do Oeste Paulista (Campus II experimental area), in Presidente Prudente, São Paulo State, Brazil. A triple factorial experimental design was used, consisting of irrigation rates (150, 100, 75, 50, 25 and 0% of the reference evapotranspiration - ETo), organic manure types (poultry and cattle manure) and manure rates (0, 3 and 5 kg m-2), with four replications. The capitula production per plant, capitula dry weight and yield per water input (water use efficiency) were evaluated. The supplementary irrigation combined with organic manure fertilization provided the highest capitula yield for chamomile crop in the Presidente Prudente region. The combination of poultry manure at rate of 5 kg m-2 with water depth equal to 150% of the ETo resulted in higher average values of capitula fresh and dry weight and water use efficiency.
TRINEXAPAC-ETHYL AFFECTS GROWTH AND GAS EXCHANGE OF UPLAND RICE
Authors: ALVAREZ RITA DE CASSIA FÉLIX , CRUSCIOL CARLOS ALEXANDRE COSTA , NASCENTE ADRIANO STEPHAN , RODRIGUES JOÃO DOMINGOS , HABERMANN GUSTAVO , NETO VESPASIANO BORGES DE PAIVA
Published: June 2016

ABSTRACT: A major problem affecting some upland rice cultivars is the increase in plant size when subjected to high doses of nitrogen fertilizer, leading to high levels of lodging. A method to reduce the height of upland rice, and therefore lodging, would be to use plant growth regulators. However, little information exists on the effect of these regulators on plant physiological processes. Therefore, the objective of this study was to evaluate the influence of trinexapac-ethyl application in upland rice via analysis of growth and gas exchange. The experiment was carried out under greenhouse conditions using the BRS Primavera cultivar. A completely randomized design with eight replications was used. Treatments were carried out with and without the application of the plant growth regulator, and plants were subject to two-stage assessments in which physiological and gas-exchange indices were measured. The use of trinexapac-ethyl improved the growth of rice plants from the flowering to the physiological maturity stage, resulting in higher values of leaf area ratio, specific leaf area, and leaf matter ratio in treated plants. At the same time, it provided smaller reduction in net CO2 assimilation at the physiological maturity stage. Thus, net/apparent assimilation rate did not change after the application of growth regulator, but relative growth rate decreased in these treated plants. These results indicate the occurrence of self-shading in rice plants induced by what might be a supra-optimum trinexapac-ethyl concentration.
PERIODS OF WEED INTERFERENCE ON TRANSGENIC COTTON 'IMACD 6001LL'
Authors: SILVA MARCOS PAULO DA , PARREIRA MARIANA CASARI , BRESSANIN FERNANDA NUNES , ALVES PEDRO LUIS DA COSTA AGUIAR
Published: June 2016

ABSTRACT: The objective of this study was to determine the periods of weed interference and its impact on productivity of cotton 'IMACD 6001LL'. The experiment was conducted in Jaboticabal, São Paulo, the second crop in 2011 and consisted of two treatment groups: the first culture remained free of competing weeds since of emergence up different periods of its development: (0-15 , 0-25, 0-35, 0-45, 0-55, 0-65, 0-75 and 0-183 days - harvest). In the second treatment group was held to the contrary: the crop was in harmony with the weeds since of emergence up to the same stages of development described above. The treatments were arranged in a randomized block design in four replications. During these periods was evaluated dry matter accumulation by weeds. The cotton yield data were subjected to regression analysis and resulting in a CPWC of 35 DAE, the CPWR was 133 DAE and .The weed community was composed mainly of Raphanus raphanistrum, Amaranthus spp., Cyperus rotundus, Alternanthera tenella and Eleusine indica. Living with this community throughout the cycle resulted in reduction almost 85% in cotton yield.
FLORISTIC-STRUCTURAL CHARACTERIZATION AND SUCCESSIONAL GROUP OF TREE SPECIES IN THE CERRADO BIOME OF TOCANTINS STATE, BRAZIL
Authors: MIGUEL EDER PEREIRA , REZENDE ALBA VALÉRIA , LEAL FABRÍCIO ASSIS , PEREIRA REGINALDO SÉRGIO , MELO RAFAEL RODOLFO DE
Published: June 2016

ABSTRACT: The objective of this study was to characterize the floristic composition, vegetation structure and ecological group of tree species in a cerradão forest (Cerrado biome) of Palmas, Tocantins State, Brazil. A forest inventory was performed in an area of 10.15 hectares, using systematic sampling with plots of 400 m², in which all standing trees, alive and dead, that had diameter at breast height (DBH) ≥ 5 cm were sampled and identified. A linear plateau regression model (LPR) was used for sample sufficiency analysis. The Shannon index (H') was used for assess the floristic diversity, and the Importance Value Index (IVI) for assess the horizontal structure. The forest was classified in three strata according to vertical structure analysis. The LPR showed that the sampling size was adequate. The predominate species in the area were Myrcia splendens, Emmotum nitens and Qualea parviflora, and species from the families Fabaceae and Chrysobalanaceae. The pioneer (613 individuals ha-1) and climax (530 individuals ha-1) species were the predominating groups. Regarding the richness index, the number of climax (57 species) and pioneer (25 species) species stood out. The alpha floristic diversity was 3.35 nats individuals-1 and the Pielou equability value J = 0.76. The diametric distribution showed a negative and balanced exponential pattern. Regarding the vertical stratification, the smallest amount of individuals was in the upper stratum (13%) and the highest in the mid stratum (63%) and in the lower stratum (24%). The use of floristic composition tools with horizontal and vertical structure analysis was effective for understand the tree community, which may be considered structured and diverse, thus able to restructure possible disturbances when preserved.
EMPIRICAL MODELS FOR PERFORMANCE OF DRIPPERS APPLYING CASHEW NUT PROCESSING WASTEWATER
Authors: SILVA KETSON BRUNO DA , BATISTA RAFAEL OLIVEIRA , MESQUITA FRANCISCO DE OLIVEIRA , COELHO DANIELA DA COSTA LEITE , SANTOS WESLEY DE OLIVEIRA
Published: June 2016

ABSTRACT: The objective of this work was to develop empirical models for hydraulic performance of drippers operating with cashew nut processing wastewater depending on operating time, operating pressure and effluent quality. The experiment consisted of two factors, types of drippers (D1=1.65 L h-1, D2=2.00 L h-1 and D3=4.00 L h-1), and operating pressures (70, 140, 210 and 280 kPa), with three replications. The flow variation coefficient (FVC), distribution uniformity coefficient (DUC) and the physicochemical and biological characteristics of the effluent were evaluated every 20 hours until complete 160 hours of operation. Data were interpreted through simple and multiple linear stepwise regression models. The regression models that fitted to the FVC and DUC as a function of operating time were square root, linear and quadratic, with 17%, 17% and 8%, and 17%, 17% and 0%, respectively. The regression models that fitted to the FVC and DUC as a function of operating pressures were square root, linear and quadratic, with 11%, 22% and 0% and the 0%, 22% and 11%, respectively. Multiple linear regressions showed that the dissolved solids content is the main wastewater characteristic that interfere in the FVC and DUC values of the drip units D1 (1.65 L h-1) and D3 (4.00 L h-1), operating at work pressure of 70 kPa (P1).
YIELD OF COMMON FIG FERTIGATED WITH BOVINE BIOFERTILIZER IN THE SEMIARID REGION OF CEARÁ
Authors: silva francisco limeira da , viana thales vinicius de araújo , sousa geocleber gomes de , costa solerne caminha , azevedo benito moreira de
Published: June 2016

ABSTRACT: The objective was to evaluate the productivity of the fig tree the organic fertirrigation cattle under different environmental conditions in Ceará semiarid region. The experiment was conducted in the experimental area of the Teaching Unit, Research and Extension, the IFCE, North Lemon Tree, EC. The experimental design was a randomized complete block design with split plots, with four replications and three plants per plot. The plots consisted of three rooms (full sun - PS; trellis - LT and greenhouse - EST), the subplots, the concentrations of bovine biofertilizer diluted in water in the following concentrations: T0 (0% of biofertilizer + 100% water); T1 (20% biofertilizer 80 +% water); T2 (40% biofertilizer + 60% water), T3 (60% biofertiliante + 40% water) and subsubplot, the production cycles. The variables were evaluated: average fruit weight, fruit diameter, number of fruits per plant and yield. The cultivation environments (greenhouse and trellis) promote better performance on average mass and diameter of the fruit compared to plants grown in full sun during the production cycles of the fig crop grown in Ceará semiarid region. The bovine biofertilizer in the concentration of 60% promoted the highest mass, diameter, number of fruits per plant and the fig crop yield.