No abstract

Jute fiber (hessian cloth)-reinforced polypropylene matrix composites (50 wt% fiber) were fabricated by compression molding. Tensile strength, tensile modulus, bending strength, bending modulus, and impact strength of the composites were found to be 48 MPa, 2.5 GPa, 56 MPa, 4.5 GPa, and 18 kJ/m2, respectively. Then E-glass fiber (woven)-reinforced polypropylene-based composites (50 wt% fiber) were fabricated and the mechanical properties were compared with those of the jute-based composites. It was revealed that E-glass fiber-based composites had almost double the mechanical properties as compared to jute composites. The interfacial shear strength of the jute and E-glass fiber-based systems was investigated and found to be 2.13 and 4.66 MPa, respectively, measured using the single-fiber fragmentation test. Fracture sides after flexural testing of both types of the composites were studied by scanning electron microscope and the results revealed poor fiber matrix adhesion for jute-based composites when compared to that of the E-glass fiber composites.

No abstract

Moderate or Intense Low oxygen Dilution (MILD) combustion is a promising technology that offers high thermal efficiency and low pollutant emissions. This study investigates the MILD combustion characteristics of pulverized coal in a laboratory-scale self-recuperative furnace. High-volatile Kingston brown coal and low-volatile Bowen basin black coal with particle sizes in the range of 38−180 μm were injected into the furnace using either CO 2 or N 2 as a carrier gas. A water-cooled sampling probe was used to conduct in-furnace gas sampling. Measurements of in-furnace gas concentration of O 2 , CO, and NO, as well as exhaust gas emissions and in-furnace temperatures, are presented. The results suggest major differences between the two coals and minor differences associated with the carrier gas. It was found that the measured CO level of brown coal cases was 10 times higher than that of black coal cases. However, NO emission for brown coal was only 37% of that measured for black coal at an equivalence ratio of Φ = 0.88. Ash content analysis showed that black coal was not burnt effectively, which is thought to be due to the particle residence times being insufficient for complete combustion in the furnace. To augment the experimental measurements, computational fluid dynamic modeling was used to investigate the effects of coal particle size and inlet air momentum on furnace dynamics and global CO emissions. It is found that coal particle size affects the coal penetration depth within the furnace and the location of the particle's stagnation point. The effects of air inlet momentum are tested in two ways: first, by raising the inlet temperature at a constant mass flow rate, and, second, by increasing the mass flow rate at a constant temperature. In both cases, increasing the air jet momentum broadens the reaction zone and facilitates MILD combustion, but also lowers reaction rates and increases CO emissions.

No abstract