Ali Khaki; َAli Akbar Yazdi Mymand; Mjtaba MirHoseini Taba; Saleh Gohari
Abstract
The increasing demand for durable and lightweight raw materials in home and office furniture makes it necessary to investigate and optimize their properties. In this study, the effect of the sheet type, layout, and thickness were investigated on the mechanical properties of lightweight sandwich panels. ...
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The increasing demand for durable and lightweight raw materials in home and office furniture makes it necessary to investigate and optimize their properties. In this study, the effect of the sheet type, layout, and thickness were investigated on the mechanical properties of lightweight sandwich panels. Two types of sheets were used for making sandwich panels; medium density fiberboards and particle boards with a thickness of 8 mm and cores made of tube (bobbins) cardboard with heights of 30 and 50 mm, in three types of layouts. Urea formaldehyde glue was selected. The bending stiffness and modulus of elasticity were evaluated according to ASTM C 393 and impact strength according to DIN 5218 1992. The results showed that the thickness of the core had a significant effect on the mechanical properties, so that with increasing the thickness of the core, bending stiffness and modulus of elasticity decrease, but impact strength increases. The best results came from specimens made with a 30mm thick, medium density fiberboard core and a Type A layout.
Physics and anatomy
Jalal Shakhes; Ahmad reza Saraeyan; Farhad Zynali
Abstract
This work investigated effect of height and cultivar on morphological properties of bast and core fiber of tobacco stalk (Nicotiana tabacum). Also, in this research cultivar effect on chemical properties of tobacco stalk were investigated. Selected cultivars include Barley and Virginia, and investigative ...
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This work investigated effect of height and cultivar on morphological properties of bast and core fiber of tobacco stalk (Nicotiana tabacum). Also, in this research cultivar effect on chemical properties of tobacco stalk were investigated. Selected cultivars include Barley and Virginia, and investigative height positions were chosen 5, 50 and 75% of stalk height. Results indicated that bast fiber length, diameter and wall thickness are more effective than those of core fiber. Chemical analysis of stalk’s parts indicated that cellulose and ash contents of bast were higher than those of core, but lignin content of bast was significantly less than that of core. Also, extractive material of bast was less. Statistic results showed that length and wall thickness of Barley’s bast fiber were higher compare to Virginia, but there was no significant difference in terms of morphological properties of core fibers between these cultivars. Cellulose percentage of Barley cultivar was higher, where as lignin, extractives and ash contents of Barley were lower than that of Virginia cultivar. Also, cultivar type didn’t have significant effect on contents of tobacco stalk parts (bast, core and pith). Results indicated that, fiber length, diameter and wall thickness of bast decreased as height increases, but in core fiber, just fiber length decreased and other properties of core fiber had different behavior. Moreover, bast and pith percentages increased by height increasing while, core percentage decreased. In general, results of this research showed that, tobacco stalk are a suitable row material for pulp and paper production, re fiber dimensions and chemical components.
