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| Registros recuperados: 58 | |
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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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| SCORZA JUNIOR, R. P.; NÉVOLA, F. A.; AYELO, V. S.. |
| Modelos matemáticos e simuladores têm sido desenvolvidos para prever a lixiviação de agrotóxicos em solos, permitindo grande economia de tempo e recursos financeiros, além de permitir análises de risco com maior representatividade e confiabilidade. O Brasil ainda não faz uso dessas ferramentas no processo de avaliação de risco e classificação ambiental dos agrotóxicos. Estas ferramentas não são utilizadas pelas autoridades nacionais por não estarem adaptadas às condições brasileiras. O presente trabalho teve como objetivo desenvolver uma ferramenta computacional para simulação da lixiviação de agrotóxicos em cenários agrícolas brasileiros. A ferramenta computacional recebeu o nome de ACHA, que se refere ao acrônimo de Avaliação da Contaminação Hídrica por... |
| Tipo: Folhetos |
Palavras-chave: Modelagem matemática; Pesticide; Mathematical modeling; Agrotóxico; Lixiviação; Leaching. |
| Ano: 2010 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/880316 |
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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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| Coutinho,Mônica Ronobo; Conceição,Wagner André dos Santos; Paraíso,Paulo Roberto; Andrade,Cid Marcos Gonçalves; Omoto,Edilson Sadayuki; Jorge,Regina Maria Matos; Maciel Filho,Rubens; Jorge,Luiz Mario de Matos. |
| A comparative analysis of the theoretical-experimental study, developed by Hsu on the hydration of Amsoy 71 soybean grain, was performed through several soaking experiments using CD 202 soybean at 10, 20, 30, 40, and 50 °C, measuring moisture content over time. The results showed that CD 202 soybean equilibrium moisture content, Xeq, does not depend on temperature and is 21% higher than that found by Hsu, suggesting that soybean cultivar exerts great influence on Xeq. The Hsu model was numerically solved and its parameters were adjusted by the least squares method, with maximum deviations of +/- 10% relative to the experimental values. The limiting step in the mass transfer process during hydration corresponds to water diffusion inside the grain, leading... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soaking; Mathematical modeling; Distributed parameters; Mass diffusivity; Equilibrium moisture. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612010000100003 |
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| Ansorena,María Roberta; Agüero,María Victoria; Goñi,María Grabriela; Roura,Sara; Ponce,Alejandra; Moreira,María del Rosario; Di Scala,Karina. |
| During postharvest, lettuce is usually exposed to adverse conditions (e.g. low relative humidity) that reduce the vegetable quality. In order to evaluate its shelf life, a great number of quality attributes must be analyzed, which requires careful experimental design, and it is time consuming. In this study, the modified Global Stability Index method was applied to estimate the quality of butter lettuce at low relative humidity during storage discriminating three lettuce zones (internal, middle, and external). The results indicated that the most relevant attributes were: the external zone - relative water content, water content , ascorbic acid, and total mesophilic counts; middle zone - relative water content, water content, total chlorophyll, and ascorbic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Butter lettuce; Quality indices; Shelf life; Mathematical modeling; Weibull distribution. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612012000200024 |
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| MARQUES,Tadeu Alcides; RAMPAZO,Érick Malheiros; ZILLIANI,Rafael Rebes; MARQUES,Patricia Angélica Alves; BENINCASA,Fabio. |
| Abstract Sugarcane monosaccharides are reducing sugars, and classical analytical methodologies (Lane-Eynon, Benedict, complexometric-EDTA, Luff-Schoorl, Musson-Walker, Somogyi-Nelson) are based on reducing copper ions in alkaline solutions. In Brazil, certain factories use Lane-Eynon, others use the equipment referred to as “REDUTEC”, and additional factories analyze reducing sugars based on a mathematic model. The objective of this paper is to understand the relationship between variations in millivolts, mass and tenors of reducing sugars during the analysis process. Another objective is to generate an automatic model for this process. The work herein uses the equipment referred to as “REDUTEC”, a digital balance, a peristaltic pump, a digital camcorder,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mathematical modeling; Monosaccharide; Chemical determination. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612016000100070 |
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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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| OMOLOLA,Adewale Olusegun; KAPILA,Patrick Francis; SILUNGWE,Henry. |
| Abstract Drying characteristics of Cleome leaves in an oven dryer was studied. The impact of oven drying temperature (50, 60 and 70 °C) on moisture composition of the plant at a uniform air speed was considered. Eight drying models, namely, simple exponential, Page, Verma, modified Henderson and Pabis, Lewis, two term exponential, Newton, logarithmic, and Wang and Singh were fitted to drying data. Modified Henderson and Pabis model satisfactorily depicts the drying behaviour of Cleome leaves. Effective moisture diffusivity of Cleome ranged from 1.03 × 10−6 to 1.77 × 10−5 m2/s. Reliance of the calculated effective diffusivity on oven temperature was unavoidable. The required activation energy for oven drying of Cleome leaves was found to be 24.46 kJ/mol.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cleome gynandra L.; Colour; Oven drying; Effective diffusivity; Mathematical modeling; Activation energy. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612019000600588 |
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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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| Registros recuperados: 58 | |
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