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| Registros recuperados: 5.225 | |
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| Spagnolo,Roger T.; Rosa,David P. da; Pinho,Marivan da S.; Schiavon,Cheiner S.; Schmechel,Diego K.. |
| ABSTRACT The use of microgranular fertilizers is currently increasing, with low application rates as an obstacle in the mechanization. This study aimed to verify the performance of helical metering mechanisms using microgranular fertilizer. Four different fertilizer-metering mechanisms were tested at two pre-established dose rates (35 and 50 kg ha−1) and seven longitudinal angles (−15°, −10°, −5°, 0°, +5°, +10°, and +15°). The experiment was carried out according to Brazilian standards. The results showed that the longitudinal inclination affects the actual fertilizer dose in all tested metering systems. Metering mechanisms with a helicoid with longitudinal and lateral overflow presented a similar dose, according to the variation of the longitudinal... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Agricultural equipment; Longitudinal inclination; Precision agriculture. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000400481 |
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| Banchi,Ângelo D.; Garcia,Angel P.; Albiero,Daniel; Galvão,Cezário B.; Favarin,Luis G. A.. |
| ABSTRACT Recently, Brazilian agriculture and the mechanization process have been improved and developed, particularly in sugarcane cultivation. The developed processes should adopt suitable management practices in terms of the technical, economic, and operational logistical aspects. As a management tool, the present study aimed to measure the impact of the accumulated use of harvesters (life in h) and agricultural productivity (Mg · ha−1) on the harvesting operational capacity (HOC). Mathematical modeling was performed on data obtained from eight sugarcane production units, and equations corresponding to the HOC as a function of the harvester's life and the crop agricultural productivity were developed. The equation that best represented the phenomenon was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Performance indicators; Maintenance management; Harvesting operational capacity; Agricultural mechanization. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000500601 |
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| Costa,Edilson; Alixame,Danieli; Silva,Abimael G. da; Pupim,Rafael de S.; Binotti,Flávio F. da S.. |
| ABSTRACT Ornamental pepper plants produced in containers under protected environments have high added value. We carried out research with an aim to evaluate the growth and development of ornamental pepper in containers of different colors under two protected environments, both with thermal-reflective screens under a polyethylene film: one with 18–22 % shading and the other with 42–50 % in colored containers (brown, blue, black, and red). The treatments formed by a 2 × 4 factorial (environments × container colors) were arranged in a completely random pattern with 4 replications and 5 plants per plot, and a joint analysis of experiments was used to compare environments. The protected environment covered with low-density polyethylene film having 42–50 % of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Capsicum frutescens; Plant ambiance; Pot colors. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000500581 |
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| Franco Junior,Hélio C.; Morais,Romulo A.; Silva,Warley G. da; Oliveira,Maria O. S.; Martins,Glêndara A. de S.. |
| ABSTRACT Cowpea beans are of great socioeconomic expression for the rural population in North and Northeastern Brazil. This legume is rich in essential nutrients and exhibits great resistance to water stress. However, for grain processing, it is fundamental to study legume behavior during the hydration process. This study aims to evaluate the mass transfer of different cowpea beans via mathematical modeling to determine the viability of hydration for commercialization as a canned product. Physical and chemical analyses of lipids and moisture were performed. The soaking process was performed in a water bath with distilled water at 30, 40, and 50 °C. The mathematical model of Peleg presented satisfactory adjustments, with R2 values ranging between 99.78% and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Leguminous; Peleg model; Hydration; Beans. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000200201 |
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| Isquierdo,Eder P.; Caldeira,Daniela S. A.; Siqueira,Valdiney C.; Martins,Elton A. S.; Quequeto,Wellytton D.. |
| ABSTRACT This study aimed to obtain and evaluate thermodynamic properties and hygroscopic equilibrium isotherms of urunday seeds as a function of air relative humidity and temperature, as well as identify the best-fitted mathematical models for adsorption phenomenon. A static-gravimetric method was used to obtain hygroscopic equilibrium moisture content. Seeds were placed in airtight containers with different saturated saline solutions for relative humidity control. These were then kept in BOD incubator chambers at 10, 20, 30, and 40 °C. Hygroscopic equilibrium moisture content decreased as temperature increased, for the same water activity. The Sigma-Copace model best-fitted seed adsorption data for equilibrium water activity intervals between 0.1129 and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Water activity; Isokinetic; Sorption isotherms; Myracrodruon urundeuva; Relative humidity. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000300374 |
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| Farias,Marcelo S. de; Dagios,Ravel F.; Santi,Antônio L.; Cherubin,Maurício R.. |
| ABSTRACT The automatic control of section shut-off in seed drills minimizes seeding overlap and can reduce productivity losses, especially in responsive crops such as corn. In that context, this study evaluated the effect of sowing overlap on the grain yield and productivity of three corn hybrids. A DB-50 precision seed drill, with 33 rows equipped with a 16-row automatic section control, was used in this experiment. A randomized block design was applied to test three corn hybrids under two sowing conditions (without sowing overlap - WOSO; and with sowing overlap - WSO), with four replications. The analyzed variables were the number of plants per hectare, the number of cobs per hectare, cob length, the number of grains per cob, the thousand grain weight,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Precision agriculture; Section control; Plant population. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000400489 |
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| Diel,Patrícia Bellé; Casarin,Vanusa A.; Stracke,Marcelo P.; Silva,Deoclécio J. C. da; Santos,Antonio V. Dos; Przyczynski,Renato. |
| ABSTRACT Faced with the increasing demand for renewable energy, researchers have developed several ways to generate them, such as biogas. Thus, the present study aims to demonstrate the economic viability of electricity generation from biodigesters in a pig farm to contribute to sustainable development by reducing pollution in the environment. Studies focused on biomass derived from pig waste are still scarce. Moreover, one of the motivations of the present study is the fact that Brazil is a major producer and exporter of pig meat, with most of the production taking place in the south and southeast regions. The methodology used is defined as exploratory, descriptive, explanatory, and applied. The scientific procedures were documentary and bibliographic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biodigesters; Renewable energies; Pig farming; Economic management model. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000200132 |
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| Cunha,João P. A. R. da; França,Jorge A. L.; Alvarenga,Cleyton B. de; Alves,Guilherme S.; Antuniassi,Ulisses R.. |
| ABSTRACT For the successful application of phytosanitary products, it is essential to understand the spraying process well. The present work aims to evaluate the spectrum and speed of the droplets produced by different spray nozzle models with air induction, working under different operating conditions. The experiment was conducted using an entirely randomized design with five repetitions in a 3 × 3 × 3 factor scheme that incorporates three nozzle models (ADIA, AIXR, and GA), three nominal flows (0.76, 1.14, and 1.51 L min−1), and three operating pressures (200, 300, and 400 kPa). The spectrum and speed of the droplets were determined directly using a real-time droplet analyzer based on high-resolution image analysis. The spray nozzle model interfered with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spray tip; Droplet spectrum; Sprayer; Application technology. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000600711 |
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| Christoforo,André L.; Barbosa,Thaina Q.; Almeida,Diego H. de; Panzera,Tulio H.; Lahr,Francisco A. R.. |
| ABSTRACT This research aimed to evaluate the effect of the number of fatigue cycles (NC, 0 – reference, 450, 4500, 45000, and 90000) for frequencies (Fr) of oscillation equal to 0.5 and 1.0 Hz on the modulus of elasticity (Em) and operating stress (σm) in the static bending of Pinus caribaea wood. Em and σm were determined taking into account three specimens (SPEC) manufactured for reference condition and another three for each of the four NC levels and each Fr level, resulting in 27 SPEC. Sixty experimental determinations were obtained, being the approximate total time of sample exposure to fatigue of 350 hours. The same specimens used to determine Em and σm for the reference condition were also used (via non-destructive tests) to obtain these properties... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fatigue; Pinus caribaea; Static bending; Analysis of variance; Regression models. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000200238 |
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| Sousa,Izabelle de P.; Rosa,André P.; Borges,Alisson C.; Renato,Natália dos S.. |
| ABSTRACT Pig farming stands out as an alternative for decentralized electrical energy production from the use of biogas energy. However, its use is still limited. Thus, this study aimed to estimate and map the biogas production, as well as determine the electric power originated by the use of biogas produced in covered lagoon biodigester from pig farms of different sizes in the state of Minas Gerais, Brazil. The research was based on data provided by the Instituto Mineiro de Agropecuária (IMA). Three forms of electric power were estimated, as follows: (i) total, (ii) current, and (iii) installed. They were estimated from the volume of manure generated at each development stage of the animals. The total electric power corresponded to 31 MW, while the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Anaerobic digestion; Covered lagoon biodigester; Energy recovery; Biogas; Pig farming. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000300396 |
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| Andrade,Willian R.; Ferreira,Cecilia de F. S.; Gates,Richard S.; Borges,Alisson C.; Santos,Tânia M. B. dos. |
| ABSTRACT This study aimed to assess the anaerobic digestion response of laying hen manure with different inclusion levels of biochar in batch reactors as measured by physicochemical parameters, biogas production and digestate quality. Four levels of biochar inclusions (0, 2.5, 5.0 and 7.5%) were tested with 3 replicates each. Twelve two-liter anaerobic batch reactors were used for 86 days at 35°C. Substrate and digestate of each treatment were assessed for monitored parameters, biogas production and digestate quality. Increased levels (0, 2.5, 5.0 and 7.5%) of biochar were found to gradually reduce total ammonia nitrogen (1794.33, 140.84, 950.81 and 509.32 mg.L-1, respectively). Despite the positive effect of biochar to accelerate initial biogas... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biogas yield; Total ammonia nitrogen; Volatile solids. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000300315 |
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| Gondim,Rubens S.; Serrano,Luiz A. L.; Maia,Aline de H. N.; Silva,Janderson P. da. |
| ABSTRACT Important losses of dwarf cashew seedlings during the establishment of orchards in the Brazilian semiarid are related to the relatively short rainy season. This study aimed to evaluate biochar and hydrophilic polymer as soil amendments to increase water retention and reduce plant death in the first year. An experiment was conducted at the Curu Station, Paraipaba, CE, Brazil, using the clone BRS 226. The experimental design consisted of randomized blocks, with amounts of 0.5, 1.0, 2.0, and 4.0 kg of cashew wood biochar and 20, 40, 60, 80 g of hydrophilic polymer applied per pit, as well as a control treatment (no soil amendment). Seedlings were submitted to an irrigation regime to avoid water stress (5 L water seedling−1 when the tensiometer... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Anacardium occidentale L.; Climate change; Adaptation; Soil amendment; Biochar. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000300344 |
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| Cavalcante,Maisa D.; Belisário,Celso M.; Oliveira,Daniel Emanuel C. de; Maia,Geisa Priscilla A. G.. |
| ABSTRACT One of the factors that hinder the usability of Cerrado fruits is their perishable nature, requiring industrial processing to ensure prolonged shelf life. This study aims to determine the optimal foaming agent for industrial processing of this fruit, and to evaluate the physicochemical characteristics and antioxidant activity of dried cagaita powder (Eugenia dysenterica DC) in foam layers at temperatures of 40, 50, 60, and 70 °C. The effectiveness of three foaming agents at various concentrations were tested, and suitable agents were identified based on a factorial analysis of density, expansion, and stability. The physicochemical characteristics of the powder, along with its vitamin A and C and total carotenoid content and antioxidant activity,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cerrado fruits; Cagaita powder; Bioactive compounds; Antioxidant activity; Vitamin C; Vitamin A; Carotenoids; Foam layer drying. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000300381 |
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| Assunção,Heli H. T. de; Cunha,João P. A. R. da; Silva,Sérgio M.; Alves,Guilherme S.; Lemes,Ernane M.. |
| ABSTRACT It is a well-known fact that the application of pesticides can be improved using an electrostatic spray due to the reduction of the application rate and increase in deposition on plant targets. However, little information exists on the use of such technology in maize crops. Thus, this study is aimed to evaluate the spray deposition on maize resulting from spray application using an electrostatic sprayer in combination with low application rates and different spray compositions. A field experiment was conducted in a randomized block having a 2×2×2 factorial design with two application rates (95 and 52 L ha-1), with or without the spray electrification, and with or without the synthetic adjuvant. The droplet electrification ability, interference of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Application rate; Electrified droplet; Spray technology; Spray deposition. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000400503 |
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| Maciel,Roberta M. G.; Afonso,Marcos R. A.; da Costa,José M. C.; Araújo,Tayla M. R.. |
| ABSTRACT Guava is a fruit that stands out for its aroma, intense flavor, vitamins, and minerals. Its availability as a powdered food enhances its commercial applications. This study aimed to evaluate mathematical models for adsorption isotherms and determine the properties and flowability of guava pulp powder obtained by foam-mat drying. The models of GAB, BET, Henderson and Oswin were fitted to determine the isotherms of powders with 4 and 8% albumin, at temperatures of 35°C and 45°C. The powders were evaluated by wall friction angle, flow index, apparent density, and particle microstructure analysis. The best fit to the isotherms was obtained by the GAB model. Wall friction angle ranged from 15.7 to 21.9° and from 13.6 to 20.4° for samples containing 4... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Tropical fruit; Food powder; Isotherm. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000300388 |
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| Almeida,Dieimisson P.; Ferreira,Marcelo da C.; Santos,Renata T. da S.; Griesang,Fabiano; Santos,Eduardo de S. dos; Timossi,Paulo C.. |
| ABSTRACT The herbicide glyphosate is sprayed with varying application volumes that result in different concentrations used in the spray solutions. Thus, this study aimed to evaluate the effect of glyphosate concentrations on the potential risk of droplet drift, surface tension of spray solution, and contact angle of droplets on surfaces. Three experiments were conducted in a completely randomized design. Drift potential was evaluated by median volumetric diameter (MVD), percentage volume of droplets with diameter smaller than 100 μm (%V<100 μm), and coefficient of uniformity (Span), with 12 replications. The surface tension of spray solutions and contact angle of droplets were evaluated on Urochloa ruziziensis leaves, paraffin film, and glass, with four... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Surface tension; Contact angle; Droplets; MVD; Congo grass. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000100069 |
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| Marey,Samy; Aboukarima,Abdulwahed; Almajhadi,Yousef. |
| ABSTRACT This study examines the capability of an artificial neural network (ANN) approach using a backpropagation-learning algorithm to predict performance parameters for a chisel plow at three field sites with differing soils. The draft force, effective field capacity (EFC), fuel consumption rate (FC), overall energy efficiency (OEE), and rate of plowed soil volume (SVR) were predicted at varying plowing speeds, plowing depths, soil moisture contents, soil bulk densities, soil texture indexes, and tractor powers. Collected field data was divided into a training set (for predicting the required parameters) and testing set (for model validation). For the ANN algorithm, the number of hidden layers, neurons, and transfer functions were varied to construct... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Backpropagation-learning algorithm; Draft; Fuel consumption; Overall energy efficiency. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000600719 |
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| Registros recuperados: 5.225 | |
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