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| Registros recuperados: 11 | |
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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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| Hauth,Michele R.; Botelho,Fernando M.; Hoscher,Renata H.; Botelho,Sílvia de C. C.; Oliveira,Gabriel H. H. de. |
| ABSTRACT The knowledge of physical properties of grains is important for the optimization of postharvest operations. Thus, this study aimed to evaluate the effect of moisture content over physical properties of different cultivars of soybean. Soybean of cultivars NS7901RR, TMG1180RR, P98Y70 and TMG132RR were used, with initial moisture content of 0.32, 0.27, 0.25 and 0.21 dry basis (d.b.), respectively. In order to dry the samples, an oven of forced air circulation was used. Samples were dried at temperature of 50 °C, being the drying procedure stopped when the moisture content of soybean was equal or inferior than 0.15 (d.b.). During drying, for interested moisture contents, physical properties were determined: bulk density, equivalent diameter,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glycine max (L.); Moisture content; Physical characteristics; Shape and size. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000400590 |
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| Corrêa,Paulo C.; Resende,Osvaldo; Garin,Silvia A.; Jaren,Carmen; Oliveira,Gabriel H. H. de. |
| The present study aimed to determine the volumetric shrinkage rate of bean (Phaseolus vulgaris L.) seeds during air-drying under different conditions of air, temperature and relative humidity, and to adjust several mathematical models to the empiric values observed, and select the one that best represents the phenomenon. Six mathematical models were adjusted to the experimental values to represent the phenomenon. It was determined the degree of adjustment of each model from the value of the coefficient of determination, the behavior of the distribution of the residuals, and the magnitude of the average relative and estimated errors. The rate of volumetric shrinkage that occurred in bean seeds during drying is between 25 and 37%. It basically depends on the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Phaseolus vulgaris L.; Moisture content; Volume; Air-drying; Physical property. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162011000400010 |
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| Borges,Alisson C.; Matos,Antônio T. de; Calijuri,Maria do C.; Oliveira,Gabriel H. H. de; Roldão,João S. F.. |
| Sistemas alagados construídos (SACs) são, atualmente, importante opção para o tratamento de resíduos e controle da poluição pontual e difusa. O uso de SACs tem aumentado ano a ano, entretanto o nível de entendimento da hidrodinâmica do processo não tem crescido na mesma proporção. Traçadores fluorescentes apresentam-se como opção na determinação de curvas de distribuição de tempos de residência (DTR) e de parâmetros hidrodinâmicos, como número de dispersão e eficiência hidráulica. A pesquisa foi realizada com o objetivo de avaliar dois corantes (rodamina WT e fluoresceína sódica) na determinação das características hidrodinâmicas de SACs com escoamento subsuperficial, operando em região de clima tropical. Os tempos de residência experimentais (τR) para os... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Comportamento hidrodinâmico; Distribuição de tempos de residência; Fluoresceína sódica; Número de dispersão; Rodamina WT; Wetlands construídas. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162009000200013 |
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| Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Oliveira,Ana P. L. R. de; Vargas-Elías,Guillermo A.; Santos,Fábio L.; Baptestini,Fernanda M.. |
| ABSTRACT The present study evaluates the influence of the level of roasting and the grind size on the moisture content and repose angle of coffee during storage. Raw coffee beans (Coffea canephora and Coffea arabica), hulled and dried, were roasted to two different levels: medium light (SCAA#65) and moderately dark (SCAA#45). The beans were then ground into three different grind sizes: fine (0.59 mm), medium (0.84 mm) and coarse (1.19 mm). An additional coffee lot was kept whole. Following grinding, samples were stored at two different temperatures (10 and 30 ºC) and analyzed after five different storage durations (0, 30, 60, 120 and 180 days). The moderately dark roast was found to have a lower moisture content. Finely ground samples had higher angles of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea arábica; Coffea canephora; Post-harvest. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000600581 |
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| Zeymer,Juliana S.; Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Baptestini,Fernanda M.; Freitas,Rita C. P.. |
| ABSTRACT Lactuca sativa seeds are highly sensitive to climate conditions; thus, they should be stored securely to maintain their qualitative and quantitative characteristics. Studies on hygroscopicity aim to decrease possible changes in agricultural products under specific environmental conditions. Accordingly, this study aims to develop an appropriate mathematical model to represent the desorption isotherms of Lactuca sativa seeds. The hygroscopic equilibrium was achieved using a static-gravimetric method at temperatures of 10, 20, 30, 40 and 50 °C and water activity in the range 0.11-0.96. Six mathematical models were fitted to the experimental data of the equilibrium moisture content of Lactuca sativa seeds. The best model was chosen based on the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mathematical modeling; Hygroscopic equilibrium; Relative humidity; Temperature. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000800568 |
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| 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 |
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| Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Vasconcelos,Wander L.; Vargas-Elías,Guillermo A.; Santos,Fábio L.; Nunes,Eduardo H. M.. |
| ABSTRACT The determination of physical properties is an important factor in the design of machinery and the scaling of post-harvest operations. The present study evaluates the influence of the level of roasting and the size of grinding on the physical properties of coffee during storage. The following physical properties were evaluated: true and bulk density, and intergranular porosity. Raw coffee beans (Coffea canephora and Coffea arabica), hulled and dried, were roasted to two different levels: medium light (SCAA#65) and moderately dark (SCAA#45). The beans were then grinded into three different sizes: fine (0.59 mm), medium (0.84 mm) and coarse (1.19 mm). An additional coffee lot was kept whole. Following grinding, samples were stored at two different... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea arábica; Coffea canéfora; Physical properties. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000700666 |
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| 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 |
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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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| Goneli,André L. D.; Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Oliveira,Ana P. L. R. de; Orlando,Roberto C.. |
| ABSTRACT Knowledge on the water sorption within agricultural products is extremely important for decision making during post-harvest procedures. In order to improve this knowledge, thermodynamic properties regarding water sorption provide useful data. Thermodynamic properties of castor beans, related to sorption, were determined. Static gravimetric technique under different conditions of temperature (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 humidity environment. After the sorption procedure, differential enthalpy, differential entropy and Gibbs free energy of this process were calculated and decreased with increased values of equilibrium moisture content. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ricinus communis L.; Moisture content; Enthalpy–entropy compensation theory. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000800757 |
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| Registros recuperados: 11 | |
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