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| Registros recuperados: 25 | |
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| Lima,Magda Aparecida de; Pazianotto,Ricardo Antonio Almeida; Villela,Omar Vieira; Paraíba,Lourival Costa. |
| ABSTRACT: This study aimed to investigate the diurnal variation of methane (CH4) emission in a flooded-irrigated rice field at different stages of the plant development under tropical climate in three growing seasons, in order to determine the most appropriate time for gas sampling in the Brazilian Southeast region. It aimed also to verify correlations between CH4 flux and air, water and soil temperatures, and solar radiation. The CH4 emissions were measured every 3-hour interval on specific days in different development stages of the flooded rice in the Experiment Station of the Agência Paulista de Tecnologia dos Agronegócios (APTA), Pólo Regional Vale do Paraíba, at Pindamonhangaba, State of São Paulo (22°55’ S, 45°30’ W), Brazil. Different CH4 emission... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Flooded rice; Methane flux; Plant development stage; Activation energy. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782018000400251 |
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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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| Sadin, Rasool; Chegini, Gholamreza; Khodadadi, Mehdi. |
| In this study tomato slices were dried with three thicknesses (3, 5 and 7 mm), three temperatures (60°C, 70°Cand 80°C) and air speed of 1.1 ms-1 in a combined infrared-hot air dryer. Distance from infrared source was 70 cm, while, input air temperature was 60°C. The experiment was conducted as factorial based on a completely randomized design. Results showed that energy consumption reduced along with the increase in temperature and slice thickness. Decrease in the slice thickness from 7 to 3 mm resulted in a significant decrease in drying time. Maximum diffusion coefficient was related to the thickness of 7 mm and the temperature of 80°C, while, the minimum value was related to the thickness of 3 mm and the temperature of 60°C. Effective diffusion... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Drying time of tomato; Diffusion coefficient; Effective diffusion coefficient; Activation energy; Tomato thin-layer drying; Infrared-hot air dryer. |
| Ano: 2017 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3780 |
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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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| 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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| Goneli,André L. D.; Araujo,Willian D.; Hartmann Filho,Cesar P.; Martins,Elton A. S.; Oba,Guilherme C.. |
| ABSTRACT: The aim of this study was to adjust mathematical models to the experimental data on the peanut kernels drying in thin layer, as well as to determine the effective diffusion coefficient and the main thermodynamic properties involved in drying of the grains under different air conditions. The peanut kernels, with a water content of 0.59 ± 0.002 (dry basis, d.b.), were dried in a forced air ventilation oven with different temperature levels (40, 50, 60 and 70 °C) until reaching a water content of 0.04 ± 0.001 (d.b.). For the experimental data, eight mathematical models traditionally used to represent the drying kinetics of thin layer of agricultural products were adjusted, also being determined the effective diffusion coefficient and the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Arachis hypogaea L.; Effective diffusivity; Activation energy; Page model; Thermodynamic properties. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162017000500994 |
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| Souza,Diene G.; Resende,Osvaldo; Moura,Lígia C. de; Ferreira Junior,Weder N.; Andrade,José W. de S.. |
| ABSTRACT Biofortified sweet potato (Ipomoea batatas) is one of the foods with the highest contributions of carotenoids in the diet, especially provitamin A carotenoids. Thus, this study aimed to analyze the drying kinetics of the biofortified sweet potato pulp using the Akaike (AIC) and Schwarz's Bayesian (BIC) information criteria for model selection, as well as determine the effective diffusion coefficient and activation energy under different drying conditions. The biofortified sweet potatoes were sliced into chips and submitted to drying in an air circulation oven at 1.0 m s−1 at temperatures of 45, 55, 65, and 75 °C until constant mass. The mathematical models Wang and Singh, Verma, Thompson, Page, Newton, Midilli et al., logarithmic, Henderson and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Liquid diffusion; Activation energy; Wang and Singh. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000200176 |
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| ISIK,Ayla; OZDEMIR,Murat; DOYMAZ,Ibrahim. |
| Abstract The aim of this study was to investigate the effect of hot air drying on quality characteristics, physicochemical properties, morphological structure and organoleptic characteristics of bee pollen, and compute the effective moisture diffusivity and activation energy during hot air drying of bee pollen. Bee pollen samples were dried at 40, 45, 50, 55 and 60 °C. Effective moisture diffusivity (Deff) values ranged from 1.38 × 10 −10 to 4.00 × 10−10 m2/s, and the activation energy (Ea) was found to be 42.96 kJ/mol. Protein, fat, total carbohydrates and vitamin C of bee pollen were affected by the drying temperature. Dried bee pollen samples had high solubility index, and had lower L* and b* values as compared with those of the fresh bee pollen. Total... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bee pollen; Hot air drying; Effective moisture diffusivity; Activation energy; Quality. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612019000100224 |
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| Benkeblia,Noureddine. |
| The respiration rate (RR) (CO2 production), activation energy (Ea) and Q10 of maleic hydrazide-treated onion bulbs (Allium cepa, cv. Rouge Amposta) at 20.10-6 mol.L-1 (MH1) and 45.10-6 mol.L-1 (MH2) were measured at 4, 10 and 20ºC. Immediately after treatment, the Q10 of MH-treated and control bulbs were not significantly different. After 8 weeks of storage, Q10 of control and both MH-treated bulbs increased and ranged from 2.34 and 2.89. Respiration rate of onions increased during storage, and after 24 weeks, RR values of control, MH1 and MH2 were 0.43, 0.32 and 0.26 mmol CO2.kg-1.h-1 at 20ºC respectively; and 0.26, 0.20 and 0.17 mmol CO2.kg-1.h-1 at 10ºC respectively. At 4ºC, no significant difference was observed between control and MH-treated bulbs.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Activation energy; MH; Onion; Q10; Respiration rate; Sprouting; Storage. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202004000100007 |
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| Ikegwu, Onyekachi John. |
| The thermal conductivity of agricultural seeds has been used as engineering parameter in the design of process and machines for drying, storing, aeration and refrigeration. The thermal conductivity of white and red pigeon pea seeds with changes in moisture content and temperature was investigated using the transient heat transfer method. The thermal conductivity of white and red pigeon pea seeds increased from 0.2387 to 0.3497 Wm-1k-1 , and 0.2375 to 0.3425 Wm-1k-1 respectively, as the moisture content increased from 5 to 35% w.b. Thermal conductivity of white and red pigeon pea seeds increased significantly (p<0.05) from 0.2643 to 0.3543 Wm-1k-1 , and from 0.2711 to 0.3311 Wm-1k-1 respectively, as temperature increased from 10 to 70 ℃. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Thermal conductivity; Pigeon pea seeds; Moisture content; Temperature; Activation energy. |
| Ano: 2021 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/6065 |
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| Azizpour, Mehran; Mohebbi, Mohebbat; Khodaparast, Mohammad Hossein Haddad; Varidi, Mehdi. |
| The effects of water: shrimp ratio and xanthan gum (XG) concentration on characteristics of shrimp foam were investigated. Foams were prepared from shrimp puree by adding several xanthan gum concentrations (0.1, 0.2, 0.3 % w/w), water: shrimp ratios (2:1, 3.5:1, 5:1 w/w) and whipped for five minutes. Incorporation of 0.2% w/w XG with 3.5:1 w/w water: shrimp ratio was selected because of having better characteristics of produced foams and then dried at 50, 60 and 70°C. Results showed that stability and density of foam increased with increasing xanthan gum concentration. However, increasing water : shrimp ratio caused to decrease in stability and density of foam. As the temperature increased from 50 to 70°C, the drying time decreased to 55 minutes.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Activation energy; Effective diffusivity; Foam-mat drying; Foam characteristics; Modeling; Shrimp. |
| Ano: 2013 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2339 |
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| Gharehbeglou, Pouria; Askari, Bijan; Homayouni Rad, Aziz; Hoseini, Seyed Sajjad; Tavakoili Pour, Hamid; Elhami Rad, Amir Hosein. |
| The drying process of turnip and drying rate curves were investigated at different temperatures (55, 70 and 85°C) with air flow rate of 1.5 m/s. Also effective diffusion coefficient and activation energy were calculated by using Arrhenius equation and Fick’s second law for infinite slab. The effective diffusivity varied between 5.471×10-10 and 8.966×10-10 in the range of (55°C to 85°C). The value of activation energy was found to be 16.013 kJ/mol. The mathematical models (Newton, Page, Modified Page, Henderson and Pabis, Logarithmic, Two term, Two term exponential, Wang and Singh, Simplified Fick’s diffusion, Modified Page –II, Verma, Midilli–Kucuk, Hii, Law and Cloke, Approximation of diffusion, Modified Henderson and Pabis) were fitted to the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Turnip; Hot air convective drying; Modeling; Drying rate; Effective diffusivity; Activation energy. |
| Ano: 2014 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2864 |
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| Silva,Hellismar W. da; Rodovalho,Renato S.; Velasco,Marya F.; Silva,Camila F.; Vale,Luís S. R.. |
| ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Capsicum chinense L.; Moisture ratio; Enthalpy; Activation energy. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000200174 |
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| Silva,Lígia C. de M.; Resende,Osvaldo; Oliveira,Daniel E. C. de; Ferreira Junior,Weder N.; Rodrigues,Gabrielly B.. |
| ABSTRACT Drying is the most widely used process to ensure the quality and stability of plant products. Therefore, this study aimed to determine the effective water diffusivity and activation energy in grain sorghum during drying at different temperatures and initial moisture contents. Sorghum grains (cultivar DeKalb 640) were harvested with an initial moisture content of 0.49 kg water kg−1 dry matter. The effective diffusion coefficient was determined from different initial moisture contents of approximately 0.49, 0.40, 0.31, and 0.23 kg water kg−1 dry matter. Grains with different moisture contents were dried under four temperature conditions of 40, 60, 80, and 100 °C on perforated trays. The spherical geometry model was used for liquid diffusion. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diffusion coefficient; Activation energy; Sorghum bicolor L.. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000600737 |
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| Oliveira, Gabriel Henrique Horta; Instituto Federal de Brasília; Corrêa, Paulo Cesar; Universidade Federal de Viçosa; Botelho, Fernando Mendes; Universidade Federal de Mato Grosso; Goneli, André Luis Duarte; Universidade Federal da Grande Dourados; Afonso Júnior, Paulo Cesar; Embrapa Café; Campos, Sílvia Carvalho; EMBRAPA Agrosilvipastoril. |
| The effects of drying conditions on the shrinkage of Coffea Arabica L., cultivar Catuaí Vermelho, were studied. An exponential model derived from the kinetic model was used to describe the shrinkage kinetics. In addition, an equation was proposed to describe the relationship between the superficial areas and weights of the coffee berries. Coffee berries were dried at temperatures (T) of 35, 45, 55 and 65ºC and at relative humidities (φ) of 25, 35, 45 and 55%, forming 16 different sets of conditions, with an initial moisture content for all conditions of 2.27 dry basis (d.b.), dried until 0.11 d.b. Changes in the product dimensions were measured continuously during drying. Surface area-to-volume ratio values increased with moisture content decrease. The... |
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Palavras-chave: 5.00.00.00-4; 5.03.00.00-8; 5.03.03.02-3 surface area-to-volume ratio; Post-harvest; Activation energy; Coffea arabica L; Shrinkage Ciências Agrárias; Engenharia Agrícola; Armazenamento de Produtos Agrícolas surface area-to-volume ratio; Post-harvest; Activation energy; Coffea arabica L; Shrinkage. |
| Ano: 2011 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/7080 |
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| Registros recuperados: 25 | |
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