جستجوی مقالات مرتبط با کلیدواژه « سنجد » در نشریات گروه « میان رشته ای »

Investigating changes in biometrics and anatomy of wood species in different parts of tree stems is one of the issues that have been of long interest to researchers in the wood and paper industry. In this study, a comparison of the anatomical and biometrical characteristics of heartwood and sapwood Elaeagnus angustifolia was made. For this purpose, a completely healthy tree native to Khorasan Province, Iran was selected and cut. Test specimens with dimensions of 2 × 2 cm and a length of 3 cm sequentially taken from near the pith (heartwood) to near bark (sapwood) were prepared for biometric and anatomical experiments. Biometric characteristics including fiber length, fiber lumen diameter, fiber diameter and cell wall thickness were evaluated. The results showed that the effect of different parts of the stem on the biometric characteristics of the fibers at the upper level was significant, so that biometric properties had an increasing trend as they moved away from the pith area and neared the bark area. Microscopic studies of wood close to the bark of the elaeagnus angustifolia showed that this species is of the ring porous hardwood species, with distinct growth ring, simple perforation plates and scalariform, alternate intervessel pits and presence of Tyloses.

To investigate the effect of wood extractives on thermal properties, wood of Elaeagnus angustifolia L. species was provided from the southern region of Hamadan. The Heartwood part was turned into wood powder.  Extraction of wood powder have been with Soxhlet method using ethanol-toluene solvents and in accordance with ASTM: D 1107-96 standard, T 204 OS-76 method. The extracted and unextracted wood powders, were examined by Thermal analysis device. The obtained graphs of Thermogravimetric analysis (TGA), Derivative of Thermogravimetric analysis (DTG) and Differential Thermal analysis (DTA) showed the wood extractives were the cause of occurred the weight loss due to degradation at higher temperature. Wood extractives have reduce on the degradation rate of thermal decomposition. The presence of extractives in wood caused greater thermal energy release due to the burning of these materials. The findings of this study demonstrated that the extractive materials in this wood increased thermal resistance.