Use of glass transition temperature for stabilization of board's cracks of Eucalyptus grandis
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Data
2010-09-01
Autores
Calonego, Fred Willians [UNESP]
Severo, Elias T.D. [UNESP]
Cunha, Antonio R. [UNESP]
Gaia, Daiane C. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Academia Brasileira de Ciências
Resumo
As temperaturas em toras de Eucalyptus grandis, durante a vaporização, foram determinadas e correlacionadas com as rachaduras das tábuas. Nos centros das toras foram inseridos termopares e registradas suas temperaturas durante a vaporização à 90C. As toras foram desdobradas e as rachaduras das tábuas mensuradas. Concluiu-se que: (1) o modelo estatístico sigmoidal logístico explica a variação da temperatura nas toras; (2) as toras com 20 a <25, 25 a <30 e 30 a <35 cm de diâmetro apresentaram, respectivamente, 84,2C, 73,1C e 45,8C ao final da vaporização; e (3) as rachaduras foramsignificativamente menores nas toras que atingiram a temperatura de transição vítrea.
The Eucalyptus grandis logs temperatures were determined and correlated with the board's cracks during steaming. Thermocouples were inserted in the logs center, registering their temperatures during steaming at 90C. The logs were sawed and the board's cracks measured. It was concluded that: (1) the logistic S-shaped curve explains the logs temperature variation; (2) the logs with diameter of 20 to <25, 25 to <30 and 30 to <35 cm presented, respectively, 84.2C, 73.1C and 45.8C in the steaming; and (3) the cracks lengths significantly decreased in logs that reached the glass transition temperature.
The Eucalyptus grandis logs temperatures were determined and correlated with the board's cracks during steaming. Thermocouples were inserted in the logs center, registering their temperatures during steaming at 90C. The logs were sawed and the board's cracks measured. It was concluded that: (1) the logistic S-shaped curve explains the logs temperature variation; (2) the logs with diameter of 20 to <25, 25 to <30 and 30 to <35 cm presented, respectively, 84.2C, 73.1C and 45.8C in the steaming; and (3) the cracks lengths significantly decreased in logs that reached the glass transition temperature.
Descrição
Palavras-chave
rachaduras de tábua, Eucalyptus grandis, temperatura de transição vítrea, vaporização de toras, board's cracks, Eucalyptus grandis, glass transition temperature, logs steaming
Como citar
Anais da Academia Brasileira de Ciências. Academia Brasileira de Ciências, v. 82, n. 3, p. 791-797, 2010.