Adaptive neutron radiography correlation for simultaneous imaging of moisture transport and deformation in hygroscopic materials

Neutron radiography is a key non-destructive testing technology for the investigation of moisture transport in materials. However, quantitative moisture measurements in swelling materials are currently challenging due to the lack of referencing between moist and dry state radiographs. A novel adaptive texture correlation algorithm is presented to simultaneously image inhomogeneous moisture distributions and moisture-induced strain fields. The proposed method provides a valuable tool for the study of time- and position-dependent hygromechanical interactions. Moreover, it requires no modification of existing neutron installations. The method was validated against gravimetric moisture content and optic surface deformation measurements. Its applicability was demonstrated for two actual topics in wood science, the investigation of moisture gradients within the growth ring microstructure and the study of moisture transport processes in wood-fiber composites. The algorithm can be widely used to characterize hygroscopic materials with heterogeneous texture, as frequently found in wood constructions, food industry, engineering and soil science

Drying kinetics of bananas by natural convection: Influence of temperature, shape, blanching and cultivar Cinética de secagem de bananas por convecção natural: Influência da temperatura, formato, branqueamento e cultivar

The influence of variables as temperature, solid shape, temperature, branching and cultivar on drying of bananas were studied. Bananas from cv. Prata and D'água, on disk and cylindrical shape, blanched or not, were dehydrated in a tray dryer in natural convection at 40 and 70ºC. Drying behavior was analyzed by using a mathematical model. The exponential model showed good agreement to experimental data (r² 0.93 - 0.99 and standard error: 0.01- 0.05). Temperature presented positive influence on drying rate in all the tested conditions. With respect to the sample shape, the disk shape carried out to significantly higher drying rates only for D'água cultivar without blanching. Blanching was significantly influent, with positive influence, on drying rate of banana cv. Prata at 40º C. The influence of the cultivar did not present a defined tendency.<br>No presente trabalho, estudou-se a influência de variáveis como temperatura, formato do sólido, branqueamento e cultivar na secagem de bananas. Bananas cultivares Prata e D'água, nos formatos disco e cilindro, branqueadas ou não, foram desidratadas em secador de bandejas com convecção natural nas temperaturas de 40 e 70ºC. O comportamento da secagem foi analisado utilizandose modelagem matemática. O modelo exponencial mostrou bom ajuste aos resultados experimentais (r²: 0,93 - 0,99 e erro de estimativa padrão: 0,01 - 0,04). A temperatura apresentou influência positiva na taxa de secagem em todas as condições testadas. Com relação ao formato das amostras, o formato disco conduziu a taxas de secagem significativamente maiores somente para o cultivar D'água e sem branqueamento. O branqueamento se mostrou significativamente influente, com influência positiva na taxa de secagem da banana Prata a 40º C. A influência da cultivar não apresentou uma tendência definida