Subhankar Biswas

Physical and mechanical properties of jute, bamboo and coir natural fiber

A systematic study has been carried out to investigate the mechanical and physical properties of jute, bamboo and coir (brown and white) single fibers. The tensile properties (tensile strength, Young’s modulus and strain to failure) were determined by varying span length. Scanning electron microscopic analysis was also carried out to determine the physical properties of fibers in order to correlate with its strength, Young’s modulus and strain to failure. The Young’s modulus and strain to failure were corrected using newly developed equations. The study revealed that with increasing test span length the Young’s modulus increased and tensile strength as well as strain to failure decreased. This is because no extensometer could be used in this test set-up and machine displacement (denoted by α) was used for the modulus determination. It is also attributed that larger span length helps to minimize the machine displacement compared to smaller ones due to the reduced relative effect of slippage in the clamps. Among all fibers, the Young’s modulus of bamboo fiber was the highest. Jute fiber had smoother surface compared to other three examined fibers.

Effect of Span Length on the Tensile Properties of Natural Fibers

Natural fibers are widely used as “reinforcing agents” in polymer composites. The aim of the current study is to evaluate the effect of span length on the tensile properties of several natural fibers (Vietnamese coir and bamboo and Bangladeshi jute). Tensile testing of jute, bamboo and coir fibers was carried out by varying span length (5, 10, 15, 25 and 35 mm). The Young’s modulus and strain to failure were corrected by using newly developed analytical equations in order to correlate the Young’s modulus and strain to failure of natural fibers. Scanning electron microscopy of the fibers was also carried out. It is clearly observed that the Young’s modulus increased with an increase in span length. Whereas tensile strength and strain to failure decreased with an increase in the span length of single fibers. The correction method resulted in a high Young’s modulus for larger span, while strain to failure found was lower compared to smaller span. This is because larger span length helps to minimize the machine displacement compared to smaller ones. Among all fibers, the Young’s modulus of bamboo fiber was highest, followed by jute and coir respectively. Jute fiber had smoother surface and compact structure compared to other two fibers.

Understanding Wear Mechanisms and Their Implication to Service Life of Pneumatic Conveying Pipelines

Pneumatic conveying is a process of transporting particulate material through pipelines using compressed gas. As material is conveyed through pipeline and bends, the pipeline especially after bends suffers severe wear due to particles’ interactions with the surfaces. Removal of material from solid surfaces by action of impinging particles is known as erosion. It is well known that particle velocity and impact angle play a major role in determining the material removal rate from the surface. In a recent study, it was demonstrated that materials’ response to deformation during impacts dictates how the material is removed from the surface. This paper presents the surface characteristics of ductile materials due to single-particle impacts as well as standard erosion using micro-sand blaster. Surface and subsurface damage characteristics with respect to the impact parameters as well as particles’ angularity have been presented. Aluminum and mild steel surfaces impacted by spherical zirconia and angular alumina particles have been analyzed using scanning electron microscope (SEM). Finally, the material removal mechanisms have been discussed with respect to the service life of pneumatic conveying pipelines.