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| Registros recuperados: 131 | |
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| Siqueira, Valdiney Cambuy; Universidade Federal de Lavras; Resende, Osvaldo; Instituto Federal de Educação, Ciência e Tecnologia Goiano - Campus Rio Verde; Chaves, Tarcísio Honório; Instituto Federal de Educação, Ciência e Tecnologia Goiano - Campus Rio Verde. |
| The objective of this study was to determine the geometric diameter of volumetric shrinkage in Jatropha seeds subjected to drying under six air conditions and to fit different mathematical models to the experimental values. Seeds with an approximate initial moisture content of 0.61 kgw kgdm-1 (kilogram of water per kilogram of dry matter) were dried in a convection oven at temperatures of 36, 45, 60, 75, 90, and 105°C until they reached a moisture content of 0.11 ± 0.006 kgw kgdm-1. The experimental data were fitted to five mathematical models used to represent volumetric shrinkage in agricultural products. The models were analyzed using the coefficient of determination, chi-square, mean relative error, mean estimated error, and residual distribution.... |
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Palavras-chave: Mathematical models; Moisture content; Polynomial model. |
| Ano: 2012 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/14402 |
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| Sheremeta, Roman; Kuzminskyj, Roman. |
| Dimensions of 100 randomly selected coffee beans of the Arabica and Robusta variety were determined by measuring their length (l), width (b) and thickness (h). The results of the measurements were processed by the methods of mathematical statistics. Parameters of distributions of separate sizes as random variables are determined. By the value of the coefficient of variation, the density function of normal distribution (Gaussian distribution) is taken as a model of separate sizes of beans. Models of two-dimensional distributions of beans sizes as independent random variables are presented. The coefficients of correlation between the geometric sizes of beans are calculated. The obtained values of the correlation coefficients indicate that the geometric sizes... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffee beans; Geometric parameters; Mathematical models; Distribution function. |
| Ano: 2019 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/5018 |
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| Moretti de Souza, Jorge Luiz; de Oliveira, Cibelle Tamiris; Kreutz Rosa, Stefanie Lais; Yoiti Tsukahara, Rodrigo. |
| Crop growth models are abstract tools that represent a real system, being a simple and important technology to develop studies aiming to improve the yields of the most agricultural crops, like the maize in Brazil. The objective of this study was to analyze the sensitivity of the main AquaCrop model input parameters, as well as their responses in maize yield estimation, in Parana State, Southern Brazil. The analyses were performed with the genotype 30R50YH, 2014/15 harvest, planted on April 11, 2014. The parameters analyzed refer to crop, soil and soil management. The parameters were modified individually, maintaining the others fixed. With the results, the Sensitivity Index (SI) was calculated, which allowed the identification of the most sensitive... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Modeling; Mathematical models; Sensitivity analysis; Maize; Zea mays. |
| Ano: 2022 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7541 |
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| FERNANDES,FRANCISCO S.; GODOY,WESLEY A.C.; RAMALHO,FRANCISCO S.; GARCIA,ADRIANO G.; SANTOS,BÁRBARA D.B.; MALAQUIAS,JOSÉ B.. |
| ABSTRACT Population dynamics of aphids have been studied in sole and intercropping systems. These studies have required the use of more precise analytical tools in order to better understand patterns in quantitative data. Mathematical models are among the most important tools to explain the dynamics of insect populations. This study investigated the population dynamics of aphids Aphis gossypii and Aphis craccivora over time, using mathematical models composed of a set of differential equations as a helpful analytical tool to understand the population dynamics of aphids in arrangements of cotton and cowpea. The treatments were sole cotton, sole cowpea, and three arrangements of cotton intercropped with cowpea (t1, t2 and t3). The plants were infested with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aphids; Cotton; Cowpea; Dynamics; Mathematical models. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000100311 |
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| CARVALHO,JULIANA O. DE; TOEBE,MARCOS; TARTAGLIA,FRANCIELI L.; BANDEIRA,CIRINEU T.; TAMBARA,ANDRÉ L.. |
| ABSTRACT The goal of this study was to estimate the leaf area of Crotalaria juncea according to the linear dimensions of leaves from different ages. Two experiments were conducted with C. juncea cultivar IAC-KR1, in the 2014/2015 sowing seasons. At 59, 82, 102, 129 days after sowing (DAS) of the first and 61, 80, 92, 104 DAS of the second experiment, 500 leaves were collected, totaling 4,000 leaves. In each leaf, the linear dimensions were measured (length, width, length/width ratio and length × width product) and the specific leaf area was determined through Digimizer and Sigma Scan Pro software, after scanning images. Then, 3,200 leaves were randomly separated to generate mathematical models of leaf area (Y) in function of linear dimension (x), and 800... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Non-destructive method; Image processing; Mathematical models; Model validation. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652017000401851 |
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| Gerrard,Andrew Mark; Havranek,Josef; Novak,Vratislav; Halecky,Martin; Jones,Kim; Soccol,Carlos Ricardo; Paca,Jan. |
| The aim of this work was the study a trickling biofilter, where water was circulated throughout the bed. In the first steady state experiment, the packing materials used were 25mm Pall rings. The airflow rate was increased gradually and the concentration of styrene in the air stream was held constant. In the second experiment, 15mm Pall rings were used. In this case, the feed contained both styrene and a small amount of acetone. The concentration of acetone and the air flow rate were kept constant, but the styrene inlet concentration was increased. The concentrations were measured at the input, and also at an intermediate and the outlet position in the biotrickling filter to determine the concentration profile along the reactor. Using the values of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biotrickling filter; Steady state; Unsteady state; Mathematical models; Styrene; Acetone. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132010000500028 |
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| Siqueira,Valdiney Cambuy; Leite,Rafael Araújo; Mabasso,Geraldo Acácio; Martins,Elton Aparecido Siqueira; Quequeto,Wellytton Darci; Isquierdo,Eder Pedroza. |
| ABSTRACT Buckwheat has become important in the food sector as its flour does not contain gluten. Since buckwheat is a relatively new crop in the agricultural environment, there is little information available regarding its processing. Drying is one of the most important post-harvest stages of buckwheat. The aim of the present study was to describe the drying process of buckwheat grains. Buckwheat grains with a moisture content of 0.41 ± 0.01 (dry basis, d.b.) were harvested, followed by drying in an experimental dryer at the temperatures of 40, 50, 60, 70, and 80 °C, at an air speed of 0.8 m s-1. The drying rate was determined, and the mathematical models generally employed to describe the drying process of several agricultural products were fitted to the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Activation energy; Fagopyrum esculentum Moench; Mathematical models; AIC and BIC; Gluten. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542020000100235 |
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| Clemente,Edmar; Afonso,Marcos Rodrigues Amorim; Souza,Ana Paula; Correia,José Maria; Pires,Raquel Gomes; Maia,Geraldo Arraes. |
| Solid mixtures for refreshment are already totally integrated to the Brazilian consumers' daily routine, because of their quick preparation method, yield and reasonable price - quite lower if compared to 'ready-to-drink' products or products for prompt consumption, what makes them economically more accessible to low-income populations. Within such a context, the aim of this work was to evaluate the physicochemical and mineral composition, as well as the hygroscopic behavior of four different brands of solid mixture for mango refreshment. The BET, GAB, Oswim and Henderson mathematical models were built through the adjustment of experimental data to the isotherms of adsorption. Results from the physiochemical evaluation showed that the solid mixtures for... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Adsorption; Isotherms; Mathematical models; Nutritious powders; Refreshment; Mango. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612011000300010 |
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| Toebe,Marcos; Souza,Rafael Rodrigues de; Mello,Anderson Chuquel; Melo,Patrícia Jesus de; Segatto,Alexandre; Castanha,Ana Carla. |
| ABSTRACT: The objectives of this work were estimate the leaf area of squash ‘Brasileirinha’ by linear dimensions of the leaves and check models available in the literature. An experiment was conducted in the 2015/16 sowing season. Were collected 500 leaves and in each one, were measured the length (L), width (W) and length×width product (LW) and determined the real leaf area (LA). Then, 400 leaves were separated to generate models of the leaf area (LA) as a function of linear dimension (L, W or LW) of squash. The remaining 100 leaves were used for the validation of models. A second experiment was conducted in the 2016/17 sowing season. Were collected 250 leaves, used only for the validation of the models of the first experiment. There is collinearity... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cucurbita moschata; Image processing; Non-destructive method; Mathematical models. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000400203 |
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| Camargo,Flávio Anastácio de Oliveira; Gianello,Clesio; Tedesco,Marino José; Riboldi,João; Meurer,Egon José; Bissani,Carlos Alberto. |
| Empirical models are mathematical equations that can be fitted to experimental results. The use of these models aims to evaluate or predict observed phenomena or experimental data with the objective of helping the development of adequate soil management practices. Based on these considerations, eight mathematical models described in the literature are compared in the present work, using as experimental data the mineral N accumulated during 32 weeks of incubation in Southern Brazilian soils. To obtain mineralization values experimentally, an incubation-washing procedure with 0.01mol L-1 CaCl2 was used. Mineral N was determined at the beginning of the incubation and in the 2nd, 4th, 8th, 16th and 32nd weeks. Among the models, the best fit was obtained with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Potentially mineralizable N; Mathematical models; Simple and double exponential; N pools. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782002000300005 |
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| Lazzaretti,Bruno Pedro; Silva,Leandro Souza da; Drescher,Gerson Laerson; Dotto,André Carnieletto; Britzke,Darines; Nörnberg,José Laerte. |
| ABSTRACT: Among the soil constituents, special attention is given to soil organic matter (SOM) and clay contents, since, among other aspects, they are key factors to nutrient retention and soil aggregates formation, which directly affect the crop production potential. The methods commonly used for the quantification of these constituents have some disadvantages, such as the use of chemical reactants and waste generation. An alternative to these methods is the near-infrared spectroscopy (NIRS) technique. The aim of this research is to evaluate models for SOM and clay quantification in soil samples using spectral data by NIRS. A set (n = 400) of soil samples previously analyzed by traditional methods were used to generate a NIRS calibration curve. The clay... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calibration; Validation; Mathematical models; Spectral pretreatment.. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782020000100251 |
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| Lima,Máida Cynthia Duca de; Barreto-Garcia,Patrícia Anjos Bittencourt; Sanquetta,Carlos Roberto; Novaes,Adalberto Brito de; Melo,Lara Clímaco de. |
| ABSTRACT: There is a large number of studies evaluating methods to quantify biomass for the genus Pinus in different regions of Brazil. However, knowledge about this subject in the Northeast region of Brazil is still incipient. The objective of the present study was to assess the biomass and carbon stocks and select mathematical models to estimate these variables in Pinus caribaea var. hondurensis , which is established in homogenous stands in the Southwest region of the state of Bahia (Brazil). The biomass was quantified using the destructive method. Samples of needles, bole, bark, and branches were analyzed to determine their carbon contents. Ten models were tested, and the best of them were chosen based on the following statistical indicators: adjusted... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Exotic forest species; Mathematical models; Biomass. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016000600957 |
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| Hernández Regalado, Evelia. |
| El presente trabajo se realizó con el propósito de modelar la fluctuación poblacional del minador de la hoja de crisantemo Liriomyza huidobrensis (Blanchard). Se propuso encontrar modelos de predicción mediante la metodología de Box-Jenkins, que pudieran representar y predecir adecuadamente la densidad de población del insecto en su etapa larval. Se trabajó en dos ciclos de cultivo con duración de cuatro meses cada uno obteniéndose dos series. El número de insectos se registró periódicamente cada 2 días obteniendo 61 observaciones para cada ciclo de cultivo; por fecha de lectura se anotó el número de larvas vivas; obteniéndose dos series de tiempo. Las primeras 55 observaciones de cada serie se analizaron para la obtención del modelo de acuerdo a... |
| Tipo: Tesis |
Palavras-chave: Liriomyza huidobrensis; Modelos matemáticos; ARIMA; Predicción de plagas; Maestría; Entomología y Acarología; Mathematical models; Pest prediction. |
| Ano: 2007 |
URL: http://hdl.handle.net/10521/1499 |
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| Velázquez Castro, Gilberto David. |
| Para complementar los servicios de información a empresas o personas físicas, en cuanto a comunicar, no sólo cambios en sus variables de interés, sino el impacto que éstos tienen sobre las actividades de la empresa, se propone un servicio que calcula tales impactos con el uso de modelos matemáticos. Se puede generar una alarma al cliente, cuando los cambios satisfagan criterios que éste define para tal efecto. De acuerdo a la urgencia indicada, se comunicará al cliente por correo electrónico, mensaje de texto o una llamada de un empleado del servicio, alguna situación que pudiera requerir una decisión oportuna.______A service to customers was conceived in order to offer information about the impact of changes in their data, rather than just report... |
| Tipo: Tesis |
Palavras-chave: Comunicación oportuna; Interpretable; Modelos matemáticos; Alarmas; Datos del entorno empresarial; Maestría; Computo Aplicado; Timely communicaction; Interpretable; Mathematical models; Alarms; Business environment data. |
| Ano: 2009 |
URL: http://hdl.handle.net/10521/1505 |
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| Silva,Fernanda P. Da; Siqueira,Valdiney C.; Quinzani,Guilherme A.; Martins,Elton A. S.; Goneli,André L. D.. |
| ABSTRACT: The objectives of this study were to describe the process of drying niger seeds through the fitting of different mathematical models to the experimental drying data, to select the best model that represents the phenomenon, and to determine the diffusion coefficients and thermodynamic properties of the product. Seeds with an initial moisture content of 0.42 (d.b) were collected and dried at 40°, 50°, 60°, 70°, and 80°C in a fixed bed experimental dryer. After drying, different mathematical models were fitted to determine the diffusion coefficient by applying liquid diffusion theory, which allowed for calculation of the energy activation, enthalpy, entropy, and Gibbs free energy values. The Page model was selected to represent the drying process of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Activation energy; Effective diffusion coefficient; Guizotia abyssinica Cass; Mathematical models. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162017000400727 |
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| Registros recuperados: 131 | |
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