Microalgal biomass is the most promising and attractive alternative to replace the terrestrial crop utilization for renewable biomass fuel feedstock. The potential for biomass fuel is due to its fast growth rate and high ability for CO₂ fixation as compared to terrestrial vegetation. There are many species in the globe, growing both in marine and freshwater. In this work, the marine microalgae Nannochloropsis oculata (N. oculata) had been investigated in terms of potential abundance and physicochemical properties, which determine its feasibility as biomass fuel feedstock. The chemical composition was evaluated by energy-dispersive X-ray spectrometry, and the proximate analysis was done by performing experiments in the thermal gravimetric analyzer. During 7 days of cultivation, the average rate of increase in algal biomass was about 1.5 × 10⁶ cells/ml/day. The proximate analysis of N. oculata indicated that it had compositions of low moisture content and fixed carbon, whereas high volatile matter and ash content, i.e., 3.99, 8.08, 67.45, and 24.47 %, respectively. The energy content, which was calculated through the proximate analysis results, was 16.80 MJ/kg. The algal biomass and its residue after 1,200 °C were characterized by Fourier transform infrared spectroscopy to investigate their chemical macromolecular compounds. This present study concludes that N. oculata is feasible as biomass fuel feedstock, either to direct or co-combustion mode by giving special attention to high ash content.

Efforts to improve the physical and chemical properties of vegetable oils as diesel fuels such as viscosity and calorific value are indispensable with the depletion of fossil oil reserves. Jatropha oil with long chain fatty acids and high degree of unsaturation is mixed with short chain saturated fatty acid coconut oil in various compositions. The mixture was heated and stirred for 30 min at 90 °C. This mixing leads to a decrease in viscosity which allows for the breaking of the bond. The fatty acid molecule structure undergoes transformation that changes the degree of unsaturation and the average length of the carbon chain. Consequently, the kinematic viscosity and flash point of the mixture decreases while its calorific value increases.

This study investigates the acoustical and nonacoustical properties of composites using corn husk fiber (CHF) and unsaturated polyester as the sound-absorbing materials. The influence of the volume fraction of CHF on acoustic performance was experimentally investigated. In addition, the nonacoustical properties, such as air-flow resistivity, porosity, and mechanical properties of composites have been analyzed. The results show that the sound absorptions at low frequencies are determined by the number of lumens in fiber, particularly the absorption coefficient, which increases the amount of fiber. For high-frequency sound, the absorption coefficient is determined by the arrangement of fibers in the composite. An absorption coefficient is close to zero when the fibers are arranged in a conventional pattern; however, when they are arranged in a random pattern, a high absorption coefficient can be obtained. The bond interface between the fiber and resin enhances its mechanical properties, which increases the longevity of the composite panel.

This research focuses on the development of a sustainable acoustic material comprising natural fibers of corn husk that were alkali modified by 1%, 2%, 5%, and 8% NaOH. The morphology and the acoustical, physical, and mechanical properties of the resulting fibers were experimentally investigated. Five different types of sample were produced in panel form, the acoustical properties of which were studied using a two-microphone impedance tube test. The porosity, tortuosity, and airflow resistivity of each panel were investigated, tensile tests were conducted, and the morphological aspects were evaluated via scanning electron microscopy. The sound absorption and tensile properties of the treated panels were better than those of raw fiber panels; the treated panels were of high airflow resistivity and had low porosity. Scanning electron micrographs of the surfaces of the corn husk fibers revealed that the different sound absorption properties of these panels were due to roughness and the lumen structures.

This study aims to experimentally determine the role of intermolecular forces on the contact angle of vegetable oil droplets. Contact angles were recorded using a microscope and measured using digital software. The results show that the surface tension of vegetable oils is influenced by the London force between the electron clouds of molecules. The process of cooling increases vegetable oil contact angles, due to the decreased kinetic energy of constituent molecules and increased London force on the molecules. A decrease in temperature causes the surrounding water vapor to condense, which adheres to the droplet surface (due to the hydrophilic properties of molecules). Hydrogen bonds develop after moisture adheres to the surface. Further, water molecules on the droplet surface reduce the surface tension, because of hydrogen bonds between the molecules on the droplet surface and moisture. Hydrogen bonds among the molecules force water molecules to accumulate on the droplet surface, which suppresses the droplet surface; therefore the contact angle decreases.