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| Registros recuperados: 47 | |
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| Gonçalves,CA; de Almeida,MA; Faria-Júnior,MJA; Pinto,MF; Garcia-Neto,M. |
| Nutritionists need to make commercial decisions about the optimal nutrient content broiler feeds. In order to demonstrate that broiler prices may influence dietary nutrient density, this study developed quadratic feed intake and weight gain equations, according to broiler sex and feeding phase, to be applied in a nonlinear feed formulation model. Four hundred and eighty Cobb broilers were allotted to a completely randomized experimental with six treatments, each with four replicates of 10 birds each, from 1 to 56 days old. Treatments consisted of diets containing 2800, 2900, 3000, 3100, 3200, or 3300 kcal metabolizable energy (ME)/kg and constant nutrient to ME ratio. A nonlinear version of the PPFR feed formulation software (http://www.fmva.unesp.br/ppfr)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Energy; Excel; Mathematical modeling; Nutrition; Response surface. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2015000200173 |
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| Ponciano,Patrícia F.; Yanagi Junior,Tadayuki; Lima,Renato R. de; Schiassi,Leonardo; Teixeira,Vitor H.. |
| The broiler rectal temperature (t rectal) is one of the most important physiological responses to classify the animal thermal comfort. Therefore, the aim of this study was to adjust regression models in order to predict the rectal temperature (t rectal) of broiler chickens under different thermal conditions based on age (A) and a meteorological variable (air temperature - t air) or a thermal comfort index (temperature and humidity index -THI or black globe humidity index - BGHI) or a physical quantity enthalpy (H). In addition, through the inversion of these models and the expected t rectal intervals for each age, the comfort limits of t air, THI, BGHI and H for the chicks in the heating phase were determined, aiding in the validation of the equations and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Thermal environment; Poultry; Thermal comfort; Mathematical modeling; Physiological responses. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162012000100002 |
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| Silva,Alysson Jalles da; Sanches,Adhemar; Andrade,Andréa Carla Bastos; Oliveira,Gustavo Hugo Ferreira de; Mauro,Antonio Orlando Di. |
| Abstract: The objective of this work was to compare the Bayesian approach and the frequentist methods to estimate means and genetic parameters in soybean multienvironment trials. Fifty-one soybean lines and four controls were evaluated in a randomized complete block design, in six environments, with three replicates, and soybean grain yield was determined. The half-normal prior and uniform distributions were used in combination with parameters obtained from data of 18 genotypes collected in previous and related experiments. The genotypic values of the genotypes of high- and low-grain yield, clustered by the Bayesian approach, differed from the means obtained by the frequentist inference. Soybean assessed through the Bayesian approach showed genetic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glycine max; Mathematical modeling; Prior distribution in plant breeding. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018001001093 |
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| Campos,Renata C.; Corrêa,Paulo C.; Fernandes,Lara S.; Baptestini,Fernanda M.; Costa,Cristian F.; Bustos-Vanegas,Jaime D.. |
| ABSTRACT This study aimed to evaluate the effect of mechanical damage on the hysteresis of beans with induced mechanical damage under different conditions of temperature and relative humidity. Beans (Phaseolus vulgaris L.) harvested manually with 35% water content (w.b.) were used. Part of this product was subjected to induced mechanical damage by Stein Breakage Tester and controlled drying (damaged and control sample), for sorption processes. The sorption isotherms of water were analyzed for different temperature conditions: 20, 30, 40 and 50 oC; and relative humidity: 0.3; 0.4; 0.5; 0.7 and 0.9 (decimal). Equilibrium moisture content data were correlated with six mathematical models, and the Modified Oswin model was the one that best fitted to the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mechanical damage; Equilibrium moisture content; Sorption isotherms; Mathematical modeling; Phaseolus vulgaris L.. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016001000930 |
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| Corrêa,Paulo Cesar; Zeymer,Juliana Soares; Oliveira,Gabriel Henrique Horta de; Araujo,Marcos Eduardo Viana de; Silva,Camilla Sena da. |
| ABSTRACT It is necessary to determine the sorption isotherms of seeds to develop adequate systems of storage and drying. The chemical composition of a product affects the sorption process; products with a high oil content adsorb a lower amount of moisture from the environment than products with a high carbohydrate content. Given the importance of the hygroscopicity of different agricultural products, this work aimed to determine, model and evaluate the difference between desorption isotherms of ryegrass and flax seeds grown at different temperature and relative humidity conditions. Ryegrass and flax seeds, which contained initial moisture contents of 10.4 and 8.7% (db), respectively, were used. The equilibrium moisture content of the seeds was determined... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equilibrium moisture content; Chemical composition; Mathematical modeling; Chung Pfost; Smith.. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542020000100215 |
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| Zeymer,Juliana S.; Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Baptestini,Fernanda M.; Freitas,Rita C. P.. |
| ABSTRACT Lactuca sativa seeds are highly sensitive to climate conditions; thus, they should be stored securely to maintain their qualitative and quantitative characteristics. Studies on hygroscopicity aim to decrease possible changes in agricultural products under specific environmental conditions. Accordingly, this study aims to develop an appropriate mathematical model to represent the desorption isotherms of Lactuca sativa seeds. The hygroscopic equilibrium was achieved using a static-gravimetric method at temperatures of 10, 20, 30, 40 and 50 °C and water activity in the range 0.11-0.96. Six mathematical models were fitted to the experimental data of the equilibrium moisture content of Lactuca sativa seeds. The best model was chosen based on the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mathematical modeling; Hygroscopic equilibrium; Relative humidity; Temperature. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000800568 |
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| Santos,Francislaine S. dos; Figueirêdo,Rossana M. F. de; Queiroz,Alexandre J. de M.; Santos,Dyego da C.. |
| ABSTRACT The objective of this work was to obtain the drying kinetic curves of white-fleshed ‘pitaya’ peels and characterize the obtained powder regarding physical and chemical parameters. Different mathematical models were fitted to the experimental data of drying kinetics, considering the coefficient of determination (R2), mean square deviation (MSD) and residual distribution as fit criteria. The peels had an initial moisture content of 93.38% (w.b.) and final moisture contents of 5.39% at temperature of 50 °C, 5.27% at 60 °C and 4.40% at 70 °C. After drying, the peels were disintegrated to obtain the powders and characterized for moisture content, reducing sugars, total titratable acidity, ascorbic acid, betacyanins, betaxanthins, water activity and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hylocereus undatus; Dehydration; Mathematical modeling; Betalains. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017001200872 |
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| Resende,Osvaldo; Oliveira,Daniel E. C. de; Costa,Lílian M.; Ferreira Júnior,Weder N.. |
| ABSTRACT This study aimed to fit different mathematical models to the experimental data on drying of baru fruits (Dipteryx alata Vogel), determine and assess the effective diffusion coefficient, as well as obtain the activation energy and thermodynamic properties for the drying process under different air temperature conditions. Baru fruits with an initial moisture content of 0.429 ± 0.044 (dry basis, db) were dried in a forced air ventilation oven under four temperature conditions (40, 60, 80, and 100 °C) until reaching a moisture content of 0.065 ± 0.018 (decimal db). These data were fitted to mathematical models frequently used to represent the drying of vegetal products. The Logarithmic model presented the best fit to describe the phenomenon. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mathematical modeling; Liquid diffusivity; Logarithmic. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000100103 |
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| Smaniotto,Thaís A. de S.; Resende,Osvaldo; Sousa,Kelly A. de; Oliveira,Daniel E. C. de; Campos,Rafael C.. |
| ABSTRACT The objectives of this study were to fit different mathematical models to experimental data of drying of sunflower grains, determine and evaluate the effective diffusion coefficient and obtain the activation energy for the process during the drying under various conditions of air. The sunflower grains were collected with an initial moisture content of 0.5267 dry basis (d.b.) and dried in an oven with forced air ventilation under five temperature conditions: 35, 50, 65, 80 and 95 °C, until reaching the moisture content of 0.0934 ± 0.0061 (d.b.). Among the analyzed models, Wang and Singh showed the best fit to describe the drying phenomenon. The effective diffusion coefficient of sunflower grains increased with the increment in air temperature and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mathematical modeling; Heliantus annus; Liquid diffusivity. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000300203 |
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| Brondani, Gilvano Ebling; Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ/USP); Wendling, Ivar; Empresa Brasileira de Pesquisa Agropecuária (Embrapa - Florestas); Brondani, André Ebling; Universidade Federal Fluminense; Araujo, Marla Alessandra; Universidade Federal de Lavras; Silva, André Luís Lopes da; Universidade Federal do Paraná; Gonçalves, Antonio Natal; Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo. |
| It is possible to determine the optimum time for permanence of vegetative propagules (mini-cuttings) inside a greenhouse for rooting, and this value can be used to optimize the structure of the nursery. The aim of this study was to determine the dynamics of adventitious rooting in mini-cuttings of three clones of Eucalyptus benthamii x Eucalyptus dunnii. Sprouts of H12, H19 and H20 clones were collected from mini-stumps that were planted in gutters containing sand and grown in a semi-hydroponic system. The basal region of the mini-cuttings was immersed in 2,000 mg L-1 indole-3-butyric acid (IBA) solution for 10 seconds. The rooting percentage of the mini-cuttings, the total length of the root system and the rooting rate per mini-cutting were also evaluated... |
| Tipo: Pesquisa |
Palavras-chave: 5.01.03.04-0 vegetative propagation; Clonal forestry; Organogenesis; Mathematical modeling; Rhizogenesis; Clonal mini-garden 5.01.03.04-0. |
| Ano: 2012 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/13059 |
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| Absalan, Ghafour; Kianmehr, Mohammad Hossein; Arabhosseini, Akbar. |
| Compost compression processes, such as pelleting, increase bulk density, improve storability, reduce transportation costs and make easier materials handling using existing equipment for handling and storage of grains. It is important to prevent quality deterioration of pellets in long time storage. Therefore, it is necessary to reduce the moisture content of the pellets to less than or less. In this research the drying kinetics of compost pellets were studied at air temperatures of 50, 60 and 70 , air velocities of 0.5, 1 and 1.5 , particle sizes of 1.18 and 2 mm and pellet diameters of 6 and 8 mm. The maximum effective moisture diffusivity (1.78× ) was obtained at air velocity of , air temperature of 70 , particle size of 1.18 mm and pellet diameter of 8... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Drying kinetics; Effective moisture diffusivity; Mathematical modeling; Pellet. |
| Ano: 2016 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3656 |
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| Machin,A.B.; Nascimento,L.F.; Mantovani,K.; Machin,E.B.. |
| Exposure to air pollution is an important cause of hospital admissions due to respiratory diseases. Nevertheless, few studies use pollutant concentration data estimated by mathematical models. A time-series ecological study was developed, using data from hospitalizations due to respiratory diseases in people over 60 years of age, residents of Cuiabá, Brazil, during 2012, obtained from the Brazilian Ministry of Health. The independent variables were the concentrations of fine particulate matter (PM2.5) and carbon monoxide (CO) estimated by mathematical modeling, minimum temperature, and relative humidity (obtained from the Brazilian Meteorological Agency), and the number of forest fires. The generalized linear regression model of Poisson was used, with lags... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Air pollutants; Particulate matter; Respiratory diseases; Elderly health; Mathematical modeling. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2019000200604 |
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| Pereira,Emmanuel M.; Silva,Wilton P. da; Gomes,Josivanda P.; Silva,Cleide M. D. P. da S. e; Formiga,Anderson dos S.; Costa,Franciscleudo B. da. |
| ABSTRACT The objective of this study was to describe the technological process involved in the drying kinetics of fresh-cut prickly pear shoots through numerical and analytical solutions. Shoots of two different prickly pear species were used, ‘Gigante’ and ‘Miúda’. Drying was performed at different temperatures (50, 60, 70 and 80 °C) and weighing procedures were made continuously. The experimental data were expressed as moisture ratio. The Page model showed the best fit to the drying kinetics of minimally processed ‘Gigante’ and ‘Miúda’ prickly pear shoots, with the best coefficients of determination and Chi-square. Peleg and Wang & Singh models can not be used to simulate the drying of ‘Gigante’ and ‘Miúda’ prickly pear shoots within the evaluated... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mathematical modeling; Opuntia; Nopalea; Minimal processing. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017001100798 |
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| Abreu,Lucas H. P.; Yanagi Junior,Tadayuki; Campos,Alessandro T.; Lourençoni,Dian; Bahuti,Marcelo. |
| ABSTRACT Broiler chickens submitted to different intensities and durations of thermal stress are subject to variation in cloacal temperature and, consequently, to a decrease in performance. Given the complexity of these interactions, artificial intelligence is a useful methodology for decision-making. Thus, this study aimed to assess and predict, by means of a fuzzy model, the cloacal temperature of broiler chickens submitted to thermal stress in the second week of life, with varying durations and intensities, in climatized wind tunnels. Mamdani's inference and defuzzification methods by means of the center of gravity were used. One hundred and twenty rules were elaborated. The developed fuzzy model was used to predict the cloacal temperature of broiler... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Physiological response; Thermal environment; Mathematical modeling; Fuzzy logic. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000100018 |
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| Oliveira,Daniel E. C. de; Resende,Osvaldo; Costa,Lílian M.; Ferreira Júnior,Weder N.; Igor O. F.,Silva. |
| ABSTRACT With the knowledge on the hygroscopic equilibrium of the baru (Dipteryx alata Vogel) fruit, the product can be adequately handled to maintain the moisture content at the levels recommended for safe storage. Thus, this paper aimed to determine the water desorption isotherms of baru fruits at temperatures of 20, 25, 30 and 35 °C, and water activity between 0.14 and 0.80, and obtain the values of isosteric heat of desorption as a function of the equilibrium moisture content of the product. The equilibrium moisture content was obtained using the static-gravimetric method. Modified Halsey was the best model recommended to represent the hygroscopicity of baru fruits. The recommended moisture contents for safe storage of baru fruits are not more than... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equilibrium moisture content; Mathematical modeling; Desorption isotherms. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000400279 |
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| Registros recuperados: 47 | |
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