Natural rubber-starch copolymer hybrid obtained from our laboratory was used as an additive for rubber compound. In this work, the effect of adding this hybrid material to vulcanization kinetics of sorghum fibers-filled natural rubber was studied. The rubber compounds were added with hybrid material at various loadings, i.e., zero to two phr and thus cured at three different temperatures, i.e., 130, 140, and 150 °C. The molecular behaviors due to the hybrid addition were investigated by Fourier-Transform Infrared (FTIR) spectroscopy. The rheological phenomena of the rubber compounds were studied by performing torque analysis in moving die rheometer. The obtained data were utilized to develop the thermodynamic modeling. The compatibility of sorghum fibers-natural rubber blends in the presence of starch-modified natural rubber were characterized using Field Emission Scanning Electron Microscope (FE-SEM). FTIR results show noticeable changes in the peak intensity of particular functional groups from rubber and natural fiber as evidence of molecular interaction enhancements between rubber and natural fibers caused by incorporating the starch-modified natural rubber coupling agent to rubber-natural fiber blends. The curing time for these blends was reduced with lower required activation energy. SEM images show no visible gaps in morphology between natural rubber and the filler indicating that the addition of hybrid material to the blends also improves the compatibility between the fibers and the rubber matrix.

This study evaluates and compared the performance of coal-fired power plants in ultrasupercritical (USC) versus integrated gasification combined cycle (IGCC). System execution in terms of net control created, exergy examination was performed to coordinate the vitality loss dispersion of this system. Base on the exergy adjust condition. The IGCC system is modeled and simulated with post-combustion capture and both used sub-bituminous coal from the Indramayu PLTU. The result display that with the same amount of raw materials (20 ton/h coal) the IGCC generated great net power than USC. IGCC produced net power of 42 MW and USC of 22 MW. The highest exergy loss in the gasifier, H2S Removal and Carbon Capture for IGCC and in Boiler, Steam Turbine system, and condenser for USC. The total exergy efficiency for IGCC was 41.51% and 33.71% in USC.

This work was aimed to investigate the effect of alkalization treatment on the fiber-matrix interfacial interaction and hence their compatibility. Kenaf fiber was treated using a 6% NaOH solution for 8 hours. The composites were produced by mixing the treated fiber with PP at various temperatures, duration, and fiber composition. Alteration on the surface chemistry of the fiber was identified by performing FTIR analysis. The surface energy of the treated fiber was mathematically derived from the contact angle measurement results. The compatibility level between treated fiber and PP matrix was visualized through FESEM analysis. Tensile strength tests were also conducted to obtain data necessary for exploring the relationship between the thermodynamic aspects of the fiber-matrix interfacial interaction and the mechanical properties of the composites. The FTIR spectra show that there was significant increase in the %transmittance at wavelength range of 3100-3600 cm-1 indicating that O-H groups were degraded during treatment. However, the polar component of the surface energy for treated fiber was instead higher compared to the untreated one. The SEM images show that there are no noticeable reduction in the size of the treated fibers as expected. On the other hand, the tensile strength of the PP-treated fibers composites reached its highest value when the matrix were loaded with fibers at the lowest percentage i.e. 5%.

This study was aimed to investigate the best control structure that provides optimal operation for dual mixed refrigerant (DMR) process. The steady-state operational map that correlates the refrigerant flow rate and the total compressor duty was drawn to locate the region the optimal operation of DMR process. This map also encompasses information of state variables in DMR process that in particular combinations provide the optimum solution. The steady-state operational map of DMR process was developed by conducting steady-state behavior analysis in a rigorous dynamic simulation of DMR process built in Aspen Hysys. The resulting steady-state operational map suggests that when the flow rate ratio of the two mixed refrigerants (WMR/CMR ratio) is kept constant, the operational of DMR process will remain within optimum region. From several control tests, the control structure that consists of WMR/CMR ratio loop has better performance on recovering the process after propagated by disturbances

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