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| Registros recuperados: 10 | |
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| Oliveira, Daniel Emanuel Cabral de; Resende, Osvaldo; Costa, Lílian Moreira; Silva, Hellismar Wakson da. |
| This study aimed to determine and evaluate the thermodynamic properties of crambe fruit at different equilibrium moisture contents. The dynamic-gravimetric method was used to collect experimental data. Crambe fruits with an initial moisture content of approximately 26% db (dry basis) were used. The thin-layer desorption of the product was conducted at different controlled temperatures (25, 30, 35, 40, and 45°C) and at water activity levels ranging from 0.10 to 0.89 until the product reached the equilibrium moisture content at the specified air condition. In conclusion, the thermodynamic properties of crambe fruit are affected by temperature and moisture content. The isokinetic theory is valid for the desorption process, which is controlled by enthalpy,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: 5.03.03.00-7 Crambe abyssinica; Enthalpy; Entropy; Gibbs free energy; Enharia de Processamento de Produtos Agrícolas. |
| Ano: 2017 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/32516 |
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| Sousa, Kelly Aparecida; Resende, Osvaldo; Goneli, André Luis Duarte; Smaniotto, Thaís Adriana de Souza; Oliveira, Daniel Emanuel Cabral de. |
| The purpose of this study was to determine the thermodynamic properties of the process of water sorption in forage turnip seeds. The equilibrium moisture content of forage turnip seeds was determined by the gravimetric-dynamic method for different values of temperature and water activity. According to the results, increasing the moisture content increases the energy required for the evaporation of water in forage turnip seeds, and the values of integral isosteric heat of desorption, within the moisture content range of 3.33 to 11.30 (% d.b.), varies from 4,222.70 to 2,870.34 kJ kg-1. With the elevation in the equilibrium moisture content, there is an increase in differential entropy and Gibbs free energy, which has positive values, demonstrating... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ciências Ágrarias; Armazenamento de produtos agrícolas hygroscopic equilibrium; Isosteric heat; Gibbs free energy; Compensation theory Ciências Ágrarias; Armazenamento de produtos agrícolas. |
| Ano: 2014 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/19333 |
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| Zeymer,Juliana Soares; Corrêa,Paulo Cesar; Oliveira,Gabriel Henrique Horta de; Araujo,Marcos Eduardo Viana de; Magalhães,Diana Soares. |
| ABSTRACT Studies about the thermodynamic properties of ryegrass seeds are necessary to improve post-harvest processes, relating the factors that affect product quality with the interaction between water and its chemical components. Given the importance of recognizing and understanding the intrinsic behavior of water in ryegrass seeds and providing data for the improvement of industrial drying equipment, this work aimed to calculate and evaluate the thermodynamic properties of moisture desorption of ryegrass seeds as a function of the equilibrium moisture content. Ryegrass seeds with initial moisture content of 10.4 (% d.b.) was used. The equilibrium moisture content of seeds was determined by static-gravimetric method at different temperatures (10, 20, 30,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gibbs free energy; Entropy; Enthalpy; Water activity; Chung Pfost.. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542020000100202 |
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| Zeymer,Juliana S.; Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Baptestini,Fernanda M.; Faria,Igor L.. |
| ABSTRACT This study aimed to determine the thermodynamic properties of sorption processes (desorption and adsorption) of rice in the husk, cv. Urucuia. A static-gravimetric method was used to reach equilibrium moisture content at different temperatures (10, 20, 30, 40, and 50 °C ± 1°C) and relative humidity levels (10, 30, 50, 70, and 90 % ± 2%). A decrease in moisture content led to an increment of the integral isosteric heat of sorption, indicating a higher demand for energy to remove moisture from the product. Differential entropy of sorption decreased along with a moisture content increment, with higher values for desorption. This indicates a higher mobility of water molecules during desorption if compared to adsorption. Gibbs free energy decreased... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equilibrium moisture content; Integral isosteric heat of sorption; Differential entropy; Gibbs free energy; Enthalpy-entropy compensation theory. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000300369 |
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| Silva,Hellismar W. da; Oliveira,Daniel E. C. de; Resende,Osvaldo; Costa,Lílian M.. |
| ABSTRACT Thermodynamic properties provide information on energy demand and kinetic parameters in water sorption processes in agricultural products. Such information is essential to analyze and scale drying and storage equipment. The objective of this study was to determine the thermodynamic properties involved in the water desorption process in Buchenavia capitata (Vahl) Eichler seeds with moisture contents ranging from 13.31 to 7.21% dry basis (d.b.), obtained by the indirect static method, at temperatures of 10, 20, 30 and 40 °C. The latent heat of vaporization, differential entropy and Gibbs free energy increase with the reduction of the moisture content of the seeds. The enthalpy-entropy compensation theory is valid for the desorption process, which is... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Latent heat; Gibbs free energy; Theory of enthalpy-entropy. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018001200878 |
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| Corrêa,Paulo C.; Baptestini,Fernanda M.; Vanegas,Jaime D. B.; Leite,Rafael; Botelho,Fernando M.; Oliveira,Gabriel H. H. de. |
| ABSTRACT This study aims to determine the thermodynamic properties of damaged beans. Grains with initial moisture content of 53.85% (d.b.) were used. A part of the grains was used to obtain the desorption isotherms, while another part was subjected to drying until a moisture content of 5.26% (d.b.) was achieved; therefore, it was subjected to the adsorption process. To induce damage, a Stein breakage tester was used. To obtain the equilibrium moisture content, grains were placed in a climatic chamber whose temperatures were 20, 30, 40, and 50 ± 1 °C combined with a relative humidity of 30, 40, 50, 70, and 90 ± 3%. Although in the desorption process, damaged grains had a lower differential enthalpy compared with the control, the reverse behavior was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Enthalpy; Entropy; Gibbs free energy. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000800556 |
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| Baptestini,Fernanda Machado; Corrêa,Paulo Cesar; Ramos,Afonso Mota; Junqueira,Mateus da Silva; Zaidan,Iasmine Ramos. |
| ABSTRACT The aim of this study was to model and determine the thermodynamic properties of moisture sorption in soursop fruit powder. The isotherms were determined by the static method at temperatures of 10, 20, 30, 40 and 50 °C, and a water activity of between 0.113 and 0.868 (decimal). The GAB model effectively described the moisture sorption phenomenon of soursop powder. The monolayer moisture content ranged from 12.589 to 9.109% db. The enthalpy values related to the GAB model were negative, with -2581.035 kJ kg-1 for C0 and -107,758 kJ kg-1 for K0. The isosteric heat of sorption, entropy and Gibbs free energy had a high correlation with the equilibrium moisture content, and the correlation between enthalpy and entropy was confirmed for moisture... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Monolayer; Entropy; Gibbs free energy; Annona muricata L. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902020000100401 |
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| Registros recuperados: 10 | |
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