Consulta: subjectFacets:"Mathematical modeling"
Registros recuperados: 47
Data/hora: 12/06/2024 13:51:43

MOISTURE SORPTION ISOTHERMS OF QUINOA SEEDS: THERMODYNAMIC ANALYSIS
Provedor de dados: 70
Autores: Bustos-Vanegas,Jaime D.; Corrêa,Paulo C.; Zeymer,Juliana S.; Baptestini,Fernanda M.; Campos,Renata C.
ABSTRACT The present research aimed to study the water sorption behavior of quinoa seeds analyzing the hysteresis phenomenon and determining thermodynamic properties. Static gravimetric technique was used to obtain the equilibrium moisture content of quinoa seeds in different temperature conditions (15, 25, 35 e 50 °C) and relative humidity (between 11 and 96%). Equilibrium moisture content data were adjusted by eight mathematical models and the Modified Halsey model was the best one to describe the water sorption phenomena of quinoa seeds. Hygroscopic equilibrium moisture content of quinoa seeds is directly proportional to the water activity and decreases with increasing temperature. The hysteresis phenomena were observed throughout the range of water...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Entropy; Gibbs energy; Hysteresis; Isosteric heat; Mathematical modeling.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000600941

OPTIMIZATION OF ANAEROBIC TREATMENT OF CASSAVA PROCESSING WASTEWATER
Provedor de dados: 70
Autores: Fleck,Leandro; Tavares,Maria H. F.; Eyng,Eduardo; Andrade,Minéia A. de M. de; Frare,Laercio M.
ABSTRACT The main contribution of this research is to optimize the operating conditions of an anaerobic reactor applied to the treatment of wastewater from cassava starch production. A 20-L anaerobic reactor was used, operating in a batch system, with temperature control. Temperature and inoculum total volatile solids (TVSi) were controlled for evaluation of effects on the removals of chemical oxygen demand (COD) and reactor total volatile solids (TVSr) by means of a Central Composite Rotational Design (CCRD). Twelve trials were analyzed simultaneously by the desirable function approach. The higher COD removal (96.82%) was obtained at 42 °C and 12.0% TVSi. The largest TVSr removal (69.31%) was registered at 45 °C and 10.0% TVSi. Equations representative of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Anaerobic reactor; Biogas; Desirability function; Mathematical modeling.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162017000300574

INFLUENCE OF DIFFERENT TEMPERATURES AND AIRFLOWS ON DRYING OF NATURAL AND PULPED COFFEE
Provedor de dados: 70
Autores: Alves,Guilherme E.; Borém,Flávio M.; Andrade,Ednilton T.; Isquierdo,Éder P.; Siqueira,Valdiney C.; Dias,Camila de A.
ABSTRACT This study aimed to evaluate drying kinetics for natural and pulped coffee, using different temperatures and drying airflows. For the conduction of the experiment, coffee fruits (Coffea arabica L. cv. Topázio) were harvested manually, selecting only ripe fruits and subsequent to the hydraulic separation. For drying the coffee, use a mechanical dryer with two temperatures (40 and 45°C) and four drying air streams (24; 60; 96 and 132 m3.min-1.m-2). Twelve models for employees to describe the drying kinetics of coffees. Among the models used to describe the drying process of natural coffee and pulped coffee, according to the results of the coefficient of determination, relative mean error, standard deviation of estimates and distribution of waste...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Coffea arabica L.; Mathematical modeling; Drying rate.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000200192

DRYING KINETICS OF BARU FRUITS (Dipteryx alata Vogel)
Provedor de dados: 70
Autores: 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

SORPTION ISOTHERMS AND ISOSTERIC HEAT OF PERICARP AND ENDOSPERM TISSUES OF ARABICA COFFEE FRUIT
Provedor de dados: 70
Autores: Dias,Camila de A.; Andrade,Ednilton T. de; Lemos,Isabella A.; Borém,Flávio M.; Barros,Ezequiel A.
ABSTRACT The aim of this study was to evaluate and model the hygroscopic equilibrium and isosteric heat curves of pericarp and endosperm tissues of arabica (Coffea arabica) coffee fruit, in different temperature and relative humidity conditions. Sorption isotherms were drawn under temperatures from 20°C to 70°C and relative humidity ranging between 10% and 90% until the product reached the equilibrium water content with the environment. The experiment was set up in a 4 × 4 factorial scheme (four relative humidity of the drying air and three tissues of the coffee cherry pericarp + endosperm [1: exocarp + part of the mesocarp, 2: mesocarp, 3: endocarp, 4: endosperm]), in a completely randomized design, with three repetitions. The results were examined by...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Adsorption; Coffea arabica; Desorption; Hygroscopic equilibrium; Mathematical modeling.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000100078

Adjust of regression models to estimate the rectal temperature of broilers for the first 14 days of life
Provedor de dados: 70
Autores: 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

FUZZY MODEL FOR PREDICTING CLOACAL TEMPERATURE OF BROILER CHICKENS UNDER THERMAL STRESS
Provedor de dados: 70
Autores: 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

Modeling and simulation of forced-air cooling of strawberries using variable convective coefficient
Provedor de dados: 70
Autores: Siqueira,Álvaro J. H.; Costa,Andréa O. da; Costa Junior,Esly F. da.
In the forced-air cooling process of fruits occurs, besides the convective heat transfer, the mass transfer by evaporation. The energy need in the evaporation is taken from fruit that has its temperature lowered. In this study it has been proposed the use of empirical correlations for calculating the convective heat transfer coefficient as a function of surface temperature of the strawberry during the cooling process. The aim of this variation of the convective coefficient is to compensate the effect of evaporation in the heat transfer process. Linear and exponential correlations are tested, both with two adjustable parameters. The simulations are performed using experimental conditions reported in the literature for the cooling of strawberries. The...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mathematical modeling; Cooling; Parameters estimation.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162012000100017

Bimodal pore distribution on soils under conservation management system for coffee crop
Provedor de dados: 70
Autores: Carducci,Carla E.; Oliveira,Geraldo C. de; Zeviani,Walmes M.; Lima,Vico M. P.; Serafim,Milson E.
This study aims at detailing bimodal pore distribution by means of water retention curve in an oxidic-gibbsitic Latosol and in a kaolinitic cambisol Latossol under conservation management system of coffee crop. Samples were collected at depths of 20; 40; 80; 120 and 160 cm on coffee trees rows and between rows under oxidic-gibbsitic Latosol (LVd) and kaolinitic cambisol Latossol (LVAd). Water retention curve was determined at matrix potentials (Ψm) -1; -2; -4; -6; -10 kPa obtained from the suction unit; the Ψm of -33; -100; -500; -1,500 kPa were obtained by the Richards extractor, and WP4-T psychrometer was used to determine Ψm -1,500 to -300,000 kPa. The water retention data were adjusted to the double van Genuchten model by nonlinear model procedures of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Psychrometer; Mathematical modeling; Cerrado soils.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162013000200008

Avaliacao da suscetibilidade natural a erosao dos solos da Bacia do Olaria, Distrito Federal.
Provedor de dados: 14
Autores: BLOISE, G. de L. F.; CARVALHO JUNIOR, O. A. de; REATTO, A.; GUIMARAES, R. F.; MARTINS, E. de S.; CARVALHO, A. P. F. de.
bitstream/CPAC-2010/22720/1/bolpd-14.pdf
Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E)
Palavras-chave: ECOSOL220; Bacia hidrografiaca; Bacia do Olaria; Distrito Federal; Brasil; Erodibilidade; Potencial erosivo; Mathematical modeling; Erosion potential; Solo: Erosao.; Cerrado; Erosão do Solo; Modelo Matemático; Topografia.; Solo; Erodibility.
Ano: 2001
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/566082

Performance of the AquaCrop model for the wheat crop in the subtropical zone in Southern Brazil
Provedor de dados: 86
Autores: Rosa,Stefanie Lais Kreutz; Souza,Jorge Luiz Moretti de; Tsukahara,Rodrigo Yoiti.
Abstract: The objective of this work was to calibrate and validate the AquaCrop model for the wheat (Triticum aestivum) crop in the Campos Gerais region, in Southern Brazil. Five cultivars were evaluated in the harvests from 2007 to 2017. The input data for AquaCrop - related to climate, crop, soil, and soil management -, collected in the field, were obtained from the database of Fundação ABC and from the literature. From 35 to 43% of total harvests were selected for calibration, and the remaining, for validation. Calibration was performed for the parameters most sensitive to crop potential yield penalty. The simulated yields were compared with those observed in the field through simple linear regression analysis, root mean square error (RMSE), Pearson’s...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Triticum aestivum; Crop yield; Mathematical modeling.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2020000101000

Bayesian approach, traditional method, and mixed models for multienvironment trials of soybean
Provedor de dados: 86
Autores: 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

Simulation of Livestock Breeding Economics in Conditions of the EU
Provedor de dados: 31
Autores: Foltyn,   Ivan; Kopecek,   Petr.
In the paper there are described mathematical principles of biological, technological and economic model relations and connections in animal breeding on which the mathematical model AGRO-ZV is based. With the model it is possible to simulate impacts of the agricultural policy on livestock breeding economics and commodity economics in dependence on different agricultural policy variants. In the article there is illustrated a usage of the model for simulation of dairy cattle economics before (2003) and after (2004) the accession of the Czech Republic to the EU.
Tipo: Conference Paper or Presentation
Palavras-chave: Mathematical modeling; Livestock breeding; Dairy cattle econmics; Model AGRO-ZV; Livestock Production/Industries.
Ano: 2005
URL: http://purl.umn.edu/24660

Accuracy of Nonlinear Formulation of Broiler Diets: Maximizing Profits
Provedor de dados: 89
Autores: 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

Performance and Egg Quality of Commercial Laying Hens Fed Diets Formulated Using Non-Linear Programming
Provedor de dados: 89
Autores: Almeida,TW; Silva,AL; Saccomani,AP; Muñoz,JA; Silva,RT; Franca,NV; Faria,DE; Faria Filho,DE.
ABSTRACT Feed formulation using linear programming consists of determining the mixture of feedstuffs required to meet pre-established animal nutritional requirements at the lowest cost. On the other hand, with the use of non-linear programming, it is possible to define nutritional requirements at the time of formulation, aiming at maximum profit. The objective of the present study was to compare feeds formulated using linear and non-linear programming in terms of live performance and internal and external egg quality of commercial laying hens. A total of 288 Hisex® White laying hens, 1.540 ± 0.128 g body weight, were evaluated from 33 to 45 weeks of age. Hens were distributed in a completely randomized block design, including six treatments with six...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Diminishing returns; Linear programming; Mathematical modeling; Meta-analysis; Profit.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2019000300313

Empirical models in the description of prickly pear shoot (Nopal) drying kinetics
Provedor de dados: 91
Autores: 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 &amp; 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

Drying kinetics of sunflower grains
Provedor de dados: 91
Autores: 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

Bean grain hysteresis with induced mechanical damage
Provedor de dados: 91
Autores: 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

Hygroscopicity of baru (Dipteryx alata Vogel) fruit
Provedor de dados: 91
Autores: 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

Isotherms and isostatic heat of foam-mat dried yellow mombin pulp
Provedor de dados: 91
Autores: Cavalcante,Maisa D.; Plácido,Geovana R.; Oliveira,Daniel E. C. de; Freitas,Bheatriz S. M. de; Cagnin,Caroline; Oliveira,Déborah de S.
ABSTRACT Yellow mombin has high nutritional value but is very perishable. Foam mat drying is a method that has been widely used to preserve liquid and semi-solid powdered foods. In this context, the aim of this study was to determine desorption isotherms and isosteric heat of yellow mombin (Spondias mombin L.) foam for different conditions of temperature and water activity. Powdered yellow mombin pulp was obtained by drying in forced-air oven regulated to 60 ° C. The indirect static method was used to determine the isotherms and isosteric heat, whereas water activity (aw) was determined using the Hygropalm-HP23AW-A analyzer. A B.O.D. incubator, set at 10, 20, 30 and 40 °C, was used to control the temperature, and the water activity for each temperature was...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Water activity; Isosteric heat; Hygroscopicity; Mathematical modeling; Spondias mombin L.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000600436

Thermodynamic and nutritional properties and drying kinetics of pequi (Caryocar brasiliense Cambess) mesocarp
Provedor de dados: 91
Autores: Souza,Jéssica L. F.; Oliveira,Daniel E. C.; Plácido,Geovana R.; Egea,Mariana B.; Caliari,Márcio; Silva,Marco A. P. da.
ABSTRACT The objectives of this study were to fit mathematical models to the experimental data of the drying of the pequi mesocarp, determine the effective diffusion coefficient, and to obtain activation energy and thermodynamic and nutritional properties in different drying conditions. The mesocarp of pequi fruits, with an initial moisture content of 5.05 (decimal, dry basis), was dried in a forced ventilation oven at temperatures of 40, 50, 60 and 70 °C until the final moisture content of 0.15 ± 0.01 (decimal, dry basis). The mathematical models were adjusted by non-linear regression analysis using the Gauss-Newton method, considering the magnitude of the coefficient of determination (R2), the mean relative error (P) and the estimated mean error (SE)....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mathematical modeling; Activation energy; Midilli model; By-product utilization.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019000900655

Desorption isotherms of Lactuca sativa seeds
Provedor de dados: 91
Autores: 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

Drying kinetics of yellow mombin (Spondias mombin L.) epicarp
Provedor de dados: 91
Autores: Pinheiro,Gleyce K. I.; Oliveira,Daniel E. C. de; Ferreira Junior,Weder N.; Resende,Osvaldo.
ABSTRACT Yellow mombin (Spondias mombin L.) fruits have relevant characteristics for industrialization and exhibit a pleasant aroma and sour-sweet taste, with significant amounts of vitamin A and carotenoids in their epicarp. The objective was to fit different mathematical models to the experimental data, using as criteria to select the best model - the Akaike Information Criteria (AIC) and Schwarz’s Bayesian Information Criteria (BIC), as well as to evaluate the effective diffusion coefficient and to determine the activation energy for yellow mombin epicarp submitted to different drying conditions. The experiment was carried out at the Instituto Federal de Educação, Ciência e Tecnologia Goiano, Brazil The epicarp of yellow mombin fruits with initial...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mathematical modeling; AIC; BIC; Midilli model.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662020000200121

Sorption isotherms of Brazil nuts
Provedor de dados: 91
Autores: Botelho,Fernando M.; Boschiroli Neto,Nilso J.; Botelho,Silvia de C. C.; Oliveira,Gabriel H. H. de; Hauth,Michele R.
ABSTRACT Knowledge of the water sorption phenomenon in Brazil nut seeds will allow proper handling of this product, especially with regard to adequate conditions for safe storage. Thus, the present study aimed to determine the sorption isotherms (desorption and adsorption) of Brazil nuts, fitting different mathematical models to the experimental data, as well as to examine the hysteresis effect. To obtain the sorption isotherms, the static method was employed at temperatures of 25, 35, 45 and 55 °C and air relative humidities varying from 10 to 80%. The psychrometric conditions of the air were acquired with the aid of acid solutions and specific saturated saline left inside desiccators with the samples. It was verified that for a given isotherm, the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bertholletia excelsa; Moisture content; Hysteresis; Mathematical modeling.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019001000776

Thermodynamic properties and drying kinetics of ‘okara’
Provedor de dados: 91
Autores: Guimarães,Rafaiane M.; Oliveira,Daniel E. C. de; Resende,Osvaldo; Silva,Jhessika de S.; Rezende,Thaisa A. M. de; Egea,Mariana B.
ABSTRACT ‘Okara’ is the insoluble part obtained after the aqueous extraction of soybeans, generated in large quantities as a by-product of the ‘tofu’ industry or soybean water-soluble extract. This work aimed to study ‘okara’ convective drying kinetics, determine the effective diffusion coefficient, and obtain activation energy and thermodynamic properties under different drying conditions. The by-product ‘okara’ was obtained from the processing of BRS 257 soybean water-soluble extract, homogenized and dried in a forced-air oven at temperatures of 40, 50, 60 and 70 °C until constant weight. Among the analysed models, Wang &amp; Singh was selected to represent the drying phenomenon. Effective diffusion coefficient increased with the temperature rise, and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mathematical modeling; Activation energy; Diffusion coefficient.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000600418

Moisture sorption isotherms of castor beans. Part 1: Mathematical modeling and hysteresis
Provedor de dados: 91
Autores: Goneli,André L. D.; Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Resende,Osvaldo; Mauad,Munir.
ABSTRACT Sorption isotherms are of great importance in post-harvest procedures, especially for predicting drying and storage, which help to establish the final moisture content of the product under certain environmental condition. Hysteresis is a phenomenon that occurs due to the difference between adsorption and desorption curves, which aids the evaluation of chemical and microbiological deteriorations, indicating the stability of stored products. Moisture sorption isotherms of castor beans were determined and hysteresis was analyzed. Static gravimetric technique at different temperatures (25, 35, 45 and 55 ± 1 °C) was used. Saturated salt solutions in the range of 37-87% ± 2% were utilized to create the required controlled relative humidity environment....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ricinus communis L.; Equilibrium moisture content; Mathematical modeling.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000800751

Physical-chemical characterization of yellow mombin (Spondias mombin L.) foam-mat drying at different temperatures
Provedor de dados: 91
Autores: Freitas,Bheatriz S. M. de; Cavalcante,Maisa D.; Cagnin,Caroline; Silva,Richard M. da; Plácido,Geovana R.; Oliveira,Daniel E. C. de.
ABSTRACT The objective of this work was to perform foam-mat drying of yellow mombin pulp, verifying the kinetics and mathematical modeling of the process, and characterizing the obtained product with respect to physical and chemical characteristics, compared with the fresh pulp. Foam-mat drying was carried out with the aid of the foam agent Emustab®, at temperatures of 50, 60, 70 and 80 °C. The drying data were analyzed and fitted to four mathematical models (Wang &amp; Singh, Verma, Page and Midilli). Effective diffusion coefficient and activation energy were determined. Titratable acidity, pH, soluble solids content and vitamin C content, as well as the solubility in water of yellow mombin powder and color variance (L*, a*, b*) were analyzed in both...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Drying kinetics; Diffusion; Mathematical modeling.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000600430

Drying kinetics and physical and chemical characterization of white-fleshed ‘pitaya’ peels
Provedor de dados: 91
Autores: 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

Length-weight relationships and prediction equations of body composition of farm raised Astyanax aff. Fasciatus (Actinopterygii: Characiformes: Characidae)
Provedor de dados: 103
Autores: Furuya,Valéria R.B.; Michelato,Mariana; Cruz,Thais P. da; Furuya,Wilson M.
This study ascertains the length-weight relationship and predicts body composition equations in cultivated Astyanax aff. fasciatus. A total of 300 fish were distributed in five groups according to body weight: 1.19 ± 0.18, 3.7 ± 0.70, 7.55 ± 0.97, 12.28 ± 2.32 and 22.16 ± 2.64 g. The length-weight relationship was elaborated using linear (y i = b0 + b1x i) or second-order (y i = b0 + b1x i + b1x i²) regression analysis. The value of the b slope in the length-weight relationship was 3.6971 and the intercept was 0.0031. The prediction equations obtained for body moisture, crude protein, crude lipid and ash were, y = 71.680 - 0.404BW, y = 17.140 - 0.095BW, y = 8.432 +0.364BW and y = 3.720 - 0.032BW, respectively, where BW is the body weight of fish (g). The...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Aquaculture; Fish; Growth; Mathematical modeling; Regression analysis.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702014000600001

Length-weight relationship and prediction equations of body composition for growing-finishing cage-farmed Nile tilapia
Provedor de dados: 96
Autores: Silva,Tarcila Souza de Castro; Santos,Lilian Dena dos; Silva,Lilian Carolina Rosa da; Michelato,Mariana; Furuya,Valéria Rossetto Barriviera; Furuya,Wilson Massamitu.
The objective of the present study was to develop models for predicting live weight from the length-weight relationship and body composition of Nile tilapia. A total of 3,000 juvenile fish (initial weight = 28.6±4.16 g and standard length = 13.8±0.16 cm) were distributed into three circular cages (12 m3 each). The fish were hand-fed extruded diets containing 332 g kg-1 of crude protein and 3,230 kcal kg-1 of digestible energy, until apparent satiety, twice daily, for 100 days. Twelve fish were collected from each cage every 20 days for measurements of body weight and length, and proximate composition analysis; statistical analysis was conducted using linear regression. The value of the slope b and the intercept for the length-weight relationship were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Amino acids; Aquaculture; Fish; Mathematical modeling.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982015000400133

Impact of global warming on beef cattle production cost in Brazil
Provedor de dados: 63
Autores: Nääs,Irenilza de Alencar; Romanini,Carlos Eduardo Bites; Salgado,Douglas D'Alessandro; Lima,Karla Andrea Oliveira; Vale,Marcos Martinez do; Labigalini,Marcelo Ricardo; Souza,Silvia Regina Lucas de; Menezes,Adriana Gomes; Moura,Daniella Jorge de.
Global warming is affecting agribusiness in its economic aspects. Therefore, the prediction of the evolution of Brazilian beef cattle production cost was made using the IPCC forecast scenario for global warming. The methodology consisted of two steps: (i) the development of a fuzzy model that estimated the grazing land capacity (RP) decrease risk as a function of the changes in the average total rain index, air temperature and increase in extension of the dry season; and (ii) the design of an algorithm for predicting the decrease in production as function of the RPfuzzy model, that results in the impact in beef cattle productivity, and consequent increase in production costs. Historical environmental data from important producing counties in the Cerrado...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Dry season; Environmental temperature; Fuzzy simulation; Mathematical modeling.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162010000100001

Dynamics of adventitious rooting in mini-cuttings of Eucalyptus benthamii x Eucalyptus dunnii - doi:  10.4025/actasciagron.v34i2.13059
Provedor de dados: 1
Autores: 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

Effective moisture diffusivity and mathematical modeling of drying compost pellet
Provedor de dados: 111
Autores: 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

Modeling of crop stem deflection in the context of combine harvester reel design and operation
Provedor de dados: 111
Autores: Moses Frank Oduori; University of Nairobi; Thomas Ochuku Mbuya; University of Nairobi; Jun Sakai; Kyushu University; Eiji Inoue; Kyushu University.
A model of crop stem deflection by the combine harvester reel is formulated.  The equations derived thereof are evaluated on the basis of empirical data that were acquired through deflection of crop stems in a ready-for-harvest Japonica rice in the field.  The empirical data are found to be in agreement with the theoretically derived equations. Applications of crop stem deflection to reel design and operation are discussed.  The derived crop stem deflection model should be applicable in other situations in which it becomes necessary to study the deflection of crop stems, particularly in the domain of agricultural machinery engineering. Keywords: combine harvester header, tined reel, crop stem deflection, rice crop, mathematical modeling, model validation,...
Palavras-chave: Combine harvester header; Tined reel; Crop stem deflection; Rice crop; Mathematical modeling; Model validation; Model application.
Ano: 2012
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/1575

Mathematical modeling of  drying kinetic of Bhimkol (Musa balbisiana) Pulp by applying master curve technique and general code developed in MATLAB
Provedor de dados: 111
Autores: WATHARKAR, RITESH BALASO; Chakraborty, Sourav; Hazarika, Manuj Kumar; Srivastava, Brijesh.
Thin layer drying kinetics of Bhimkol pulp was carried out on the basis of a general code developed in MATLAB R2012a software. In this code, single input of the drying parameters helps to provide very precise and petite analysis of batches of drying experiment at different temperatures. Drying experiment was carried out in a dehumidified dryer at 40, 50 and 60  temperatures respectively. Among the five thin layer drying models used for the analysis, Midilli Kucuk showed best fitted result with greatest  value and lowest RMSE and SSE values.For better generalization of the drying model, an attempt of master curve technique was also carried out. Master curve technique gave better fit with a R2 value of 0.9969 than the global drying constant method and normal...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Thin layer drying; Mathematical modeling; Drying kinetics; General code; Master curve.
Ano: 2018
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/4483

Nutrient and phytoplankton biomass in the Amazon River shelf waters
Provedor de dados: 42
Autores: Santos,Maria L.S.; Muniz,Kátia; Barros-Neto,Benício; Araujo,Moacyr.
The Amazon River estuary is notable at the Amazon Continental Shelf, where the presence of the large amount of water originating from the Amazon during the river's falling discharge period was made evident by the low salinity values and high nutrient levels. Even so, the presence of oceanic waters in the shelf area was significant. Dissolved organic nitrogen was the predominant species of the nitrogen cycle phases, followed by total particulate nitrogen, nitrate, ammonium and nitrite. The chlorophyll a data in the eutrophic area indicated that there is sufficient nitrogen in the area to withstand productivity, though dissolved inorganic nitrogen removal processes are faster than regeneration or mineralization. The anomalous amounts of inorganic dissolved...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Amazon Continental Shelf; Nitrogen; Phosphate; Mathematical modeling.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652008000400011

State estimation and optimal long period clinical treatment of HIV seropositive patients
Provedor de dados: 42
Autores: Grégio,Juliana M.; Caetano,Marco A.L.; Yoneyama,Takashi.
Optimal control theory provides a very interesting quantitative method that can be used to assist the decision making process in several areas of application, such as engineering, biology, economics and sociology. The main idea is to determine the values of the manipulated variables, such as drug doses, so that some cost function is minimized, subject to physical constraints. In this work, the cost function reflects the number of CD4+T cells, viral particles and the drug doses. It is worth noticing that high drug doses are related to more intense side-effects, apart from the impact on the actual cost of the treatment. In a previous paper by the authors, the LQR - Linear Quadratic Regulator approach was proposed for the computation of long period...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: AIDS; Filtering; Drugs; Mathematical modeling; Optimization.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652009000100002

Modeling the Growth of Byssochlamys fulva on Solidified Apple Juice at Different Temperatures
Provedor de dados: 52
Autores: Longhi,Daniel Angelo; Tremarin,Andréia; Carciofi,Bruno Augusto Mattar; Laurindo,João Borges; Aragão,Gláucia Maria Falcão de.
The aim of this study was to establish primary and secondary models to describe the growth kinetics of Byssochlamys fulva on solidified apple juice at different temperatures. B. fulva was inoculated on solidified apple juice at 10, 15, 20, 25 and 30 °C. Linear-with-breakpoint, Baranyi and Roberts, and Huang primary models (without upper asymptote) were fitted to the data, and they showed good ability to describe the growth kinetics. B. fulva showed longer adaptation time on apple juice than on culture medium, but growth rates were similar as reported in the literature. The dependence of µmax and λ parameters on temperature was described with Square Root and Arrhenius-Davey secondary models, respectively. These models were important to establish...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mould growth; Mathematical modeling; Food microbiology; Predictive mycology.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132014000600971

Investigation on chemical composition and optimization of essential oil obtainment from waste Pinus taeda L. using hydrodistillation
Provedor de dados: 52
Autores: Teixeira,Sirlei Dias; Fiorio,Jhonatan Luiz; Galvan,Diego; Sefstrom,Carolina; Cogo,Priscila Morgana; Sales Junior,Valber; Rodrigues,Márcio Barreto; Hendges,Ana Paula Palaro Klein; Maia,Beatriz Helena L. de Noronha Sales; Benghi,Thalita Gilda Santos.
ABSTRACT: The extraction of essential oils obtained by the hydrodistillation of needles/twigs waste of Pinus taeda L. was optimized by applying response surface methodology (RSM), with 24 full factorial design, in order to improve oil essential production, and aggregate value to the production chain of pine wood. Through the model it was possible to ascertain the influence of the variables in the average amount of essential oil (0.1032 mL), being the variables analyzed: biomass - Bm (x1), extraction time - ET (x2), Bm:ET (x1x2) and sample size - SS: drying times - DT (x3x4). Only linear terms (biomass and extraction time) and your interaction demonstrated significant positive values (0.0344, 0.0206 and 0.0131). The major components of the essential oil...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Pinus; Byproduct; Essential oil; Response surface methodology (RSM); Mathematical modeling.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132016000100603

Modeling, simulation, and analysis of a reactor system for the generation of white liquor of a pulp and paper industry
Provedor de dados: 52
Autores: Andreola,Ricardo; Jorge,Regina Maria Matos; Santos,Onélia Aparecida Andreo dos; Jorge,Luiz Mario de Matos.
An industrial system for the production of white liquor of a pulp and paper industry, Klabin Paraná Papéis, formed by ten reactors was modeled, simulated, and analyzed. The developed model considered possible water losses by the evaporation and reaction, in addition to variations in the volumetric flow of lime mud across the reactors due to the composition variations. The model predictions agreed well with the process measurements at the plant and the results showed that the slaking reaction was nearly complete at the third causticizing reactor, while causticizing ends by the seventh reactor. Water loss due to slaking reaction and evaporation occurred more pronouncedly in the slaker reactor than in the final causticizing reactors; nevertheless, the lime...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Slaker reactor; Causticizing reactor; White liquor; Mathematical modeling; Simulation.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132011000100024

Effects of exposure to fine particulate matter in elderly hospitalizations due to respiratory diseases in the South of the Brazilian Amazon
Provedor de dados: 56
Autores: 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

Mathematical modeling of electro-rotation spectra of small particles in liquid solutions: Application to human erythrocyte aggregates
Provedor de dados: 56
Autores: Zehe,A.; Ramírez,A.; Starostenko,O.
Electro-rotation can be used to determine the dielectric properties of cells, as well as to observe dynamic changes in both dielectric and morphological properties. Suspended biological cells and particles respond to alternating-field polarization by moving, deforming or rotating. While in linearly polarized alternating fields the particles are oriented along their axis of highest polarizability, in circularly polarized fields the axis of lowest polarizability aligns perpendicular to the plane of field rotation. Ellipsoidal models for cells are frequently applied, which include, beside sphere-shaped cells, also the limiting cases of rods and disks. Human erythrocyte cells, due to their particular shape, hardly resemble an ellipsoid. The additional effect...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Electro-rotation spectra; Induced dipole moment; Mathematical modeling; Erythrocyte aggregates.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000200003

Freeze-drying microscopy in mathematical modeling of a biomaterial freeze-drying
Provedor de dados: 60
Autores: Borgognoni,Camila Figueiredo; Bevilacqua,Joyce da Silva; Pitombo,Ronaldo Nogueira de Moraes.
Transplantation brings hope for many patients. A multidisciplinary approach on this field aims at creating biologically functional tissues to be used as implants and prostheses. The freeze-drying process allows the fundamental properties of these materials to be preserved, making future manipulation and storage easier. Optimizing a freeze-drying cycle is of great importance since it aims at reducing process costs while increasing product quality of this time-and-energy-consuming process. Mathematical modeling comes as a tool to help a better understanding of the process variables behavior and consequently it helps optimization studies. Freeze-drying microscopy is a technique usually applied to determine critical temperatures of liquid formulations. It has...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Freeze-drying microscopy; Bovine pericardium; Mathematical modeling.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502012000200003

Tomato Infrared Drying: Modeling and some Coefficients of the Dehydration Process
Provedor de dados: 117
Autores: Cesar Corrêa,Paulo; Horta de Oliveira,Gabriel Henrique; Machado Baptestini,Fernanda; Martins Silva Diniz,Mayra Darliane; Almeida da Paixão,Aline.
Infrared dehydration is more advantageous than the convective system under similar conditions, and studying this process is important to further develop equipment and procedures. Thus, the aim of this work was to study the dehydration process of tomato (Solanum lycopersicum L.) slices obtained by infrared drying at three different maturity stages throughout two different procedures: Firstly, the drying model was determined by applying the mass and energy balances under wet bulb temperature for the constant drying rate period and secondly, the mass effective diffusion coefficient was determined throughout the experimental data and the theory of diffusion of the liquid phase for the decreasing drying rate period. Tomato fruits cv. Santa Cruz were used. Three...
Tipo: Journal article
Palavras-chave: Critical moisture content; Diffusion; Finite element method; Heat and mass transfer; Mathematical modeling.
Ano: 2012
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392012000200015

Drying kinetics modeling of apple and zucchini slices vacuum impregnated with anthocyanins
Provedor de dados: 65
Autores: Zapata,Luz Marina; Castagnini,Juan Manuel; Quinteros,Carlos Fabio; Veuthey,Mariana Jimenez.
ABSTRACT:  The aim of this research was to study the drying kinetics of apple and zucchini slices enriched with anthocyanins and to evaluate the influence of drying temperature on the anthocyanin content of apple and zucchini snacks. Apple (Granny Smith) and zucchini (Cucurbita pepo) slices were enriched with anthocyanins by vacuum impregnation with blueberry juice. Then, slices were dehydrated at 40, 50 and 60 ºC with 1.0 m/s air flow. Dehydrated samples were referred to as anthocyanin enriched snacks. Diffusion coefficient values improved by increasing the drying temperature, within the 2.81×10-10 to 5.78×10-10 m2/s range for apple slices and 2.02×10-10 to 3.99×10-10 m2/s for zucchini slices. The activation energy was 31.19 kJ/mol and 80.33 kJ/mol for...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Drying kinetics; Mathematical modeling; Functional snacks; Anthocyanins.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019001000755

Solar Tunnel Drying: Pretreatment on drying kinetic of plum tomatoes
Provedor de dados: 65
Autores: Karaaslan,Sevil; Ekinci,Kamil; Kumbul,Barbaros Salih.
ABSTRACT:  Drying of thin layer tomato was studied using a solar tunnel dryer under the ecological conditions of Isparta, Turkey. During drying process, solar irradiation, drying air temperature, relative humidity, and air velocity were measured constantly in different parts of the dryer. Drying runs were performed using plum tomatoes, characterized by an oval shape, intense red color. The change of tomatoes mass was measured daily. The color measurements of dried products were determined at the beginning and end of experiment. In this study, the fresh tomato samples were sorted, graded, washed in water and then sliced into quarters and halves before pretreated. Sun drying behavior of half and quarter sliced tomatoes pretreated with 10% NaCl solution and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Drying characteristics; Tomato slices; Tunnel dryer; Mathematical modeling.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000700203

Comparison between desorption isotherm curves of ryegrass (Lolium multiflorum L.) and flax (Linum usitatissimum L.) seeds
Provedor de dados: 64
Autores: 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