This study examined possible feasibility of canola (Brassica napus) straws in the production of particleboard. Three-layer experimental particleboards with density 0,7 g/cm 3 were manufactured using different canola straws particle ratios (0%, 25%, 50%, 75% and 100%) and urea formaldehyde (UF) adhesive. Modulus of elasticity (MOE), modulus of rupture (MOR), internal bond strength (IB), water absorption (WA) and thickness swelling (TS) properties of the boards were evaluated and a statistical analysis was performed in order to examine possible feasibility of these straws in commercial particleboard manufacturing. The results indicated that, the addition of canola straws particle significantly improved modulus of rupture and modulus of elasticity of the panels and greatly reduced their internal bonding. Overall findings showed that most panels made from above-mentioned materials exceed the EN Standards for MOR, MOE and IB. Also, the water absorption and thickness swelling increased with increasing canola straws content in the panels. The experimental results have shown that production of general purpose and furniture grade particleboard used in dry conditions using canola straws is technically viable. The results of the study demonstrate that canola straws can be an alternative raw material source for particleboard industry.

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Residual stresses have become an important player in the field of structural integrity for many years. Exact knowledge of residual stress distributions is essential in designing the engineering components as unexpected failures are inevitable wherever such stresses are ignored. There are many residual stresses measurement techniques including destructive and non-destructive ones. Among the mechanical strain relief (MSR) techniques, contour method is one of the youngest. Contour method relies on the material removal similar to other MSR techniques. In this method a part is carefully cut into two pieces along a flat plane, causing the residual stress normal to the cutting plane to relax. However, similar to other MSR techniques, plasticity can have a great influence on the accuracy of the results. In the present work, effect of plasticity on the residual stress measurement using contour method is investigated. Quenching is employed to induce residual stresses within the samples. To create different levels of plasticity, the samples were quenched at three different temperatures, 500°C, 700°C and 850°C. The residual stresses were then measured using contour method. Furthermore, the contour method procedure is simulated using finite element analysis to compare with the experimental results.

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A proper knowledge of the mechanical properties and residual stresses of materials has a significant role in the prediction of engineering failures. Indentation is a simple, nondestructive test that is capable of estimating both residual stresses and mechanical properties. In frequent studies, the response of materials during the indentation process has been used as a key parameter to distinguish different substances. Here, a state-of-the-art method with no undesirable restriction is suggested to attain the work hardening exponent, yield strength, and planar nonequibiaxial residual stresses. In the current work, an extensive series of Knoop indentation simulations were performed using two indenter angles. Subsequently, a precise observation was made in order to find existent relationships. A local method was employed based on characteristics of similar materials to obtain stress-free sample parameters through a genetic algorithm, and then another error function was defined in order to measure the yield strength and work hardening exponent. After the determination of the mechanical properties and the stress-free sample’s parameters, a particular and precise categorization was made. Then, neural network analysis was employed to derive planar residual stresses. Experimental validation was conducted using six types of aluminum and steel specimens. The results confirmed a good agreement between the test data and those predicted using the suggested procedure.

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This study uses a combination of wood flour, obtained from kiwi twigs, together with refined fibers and polypropylene material to make a hybrid composite of polypropylene/wood/fiber. The materials were mixed in a twin-screw extruder, and the samples were made via an injection molding method. The tensile, flexural, and impact strengths, as well as the physical characteristics were measured based on ASTM standards. The results indicated that when the flour dimensions were reduced from 20 mesh to 40 mesh, the tensile and flexural strength, tensile and flexural modulus, and elongation at break were reduced. The notched impact strength, water absorption, and thickness swelling during 2 h and 24 h of immersion in water, and the water absorption and thickness swelling during 2 h immersion in boiling water, increased. In addition, by increasing the amount of refined fiber instead of kiwi wood flour, the tensile and flexural strength, tensile and flexural modulus, elongation at break, and the notched impact strength were increased. The water absorption and thickness swelling during 24 h of immersion in water and the water absorption and thickness swelling during 2 h immersion in boiling water were decreased.