Search

The rapid development of the industrial sector has increased either energy demand or generate a tremendous effect on waste piles. To combat the issue of poor sanitation due to waste accumulation and multiply the energy sources, the government promotes energy diversification, particularly dealing with waste management. This study aims to recycle plastic waste, paper waste and sawdust into solid fuel briquettes while observing their physical and combustion properties. Briquette production is carried out by combining waste of plastics and sawdust with binding agents, such as paper pulp and cassava starch. These materials were mixed with water, being compacted and conventionally dried under the sunlight. Solid briquette was then tested for calorific value, moisture content and volatile matter to ensure the effectiveness of combustion. The results show that the modified composition of plastic and paper with the ratio of 3:1 is physically sturdy with minor cracks, has a greater calorific value of 6801.62 Cal/gr, low moisture content (4.73%) and volatile matter (5.50%). The modified composition of paper: plastic: sawdust with the ratio of 1:1:1 exhibits more sturdy stuff, with a calorific value of 4565.47 Cal/ gr, low moisture content (1.85%) but high volatile matter (34.07%). Waste conversion to solid fuel briquette can be utilized as future green energy alternative in any major cities of Indonesia. A modified mixture of plastic : paper waste is more prone to transmit the heat despite having less capability to ignite, while the mixture of sawdust : paper is more prone to ignite despite having less capability to store and dismiss the heat. [ABSTRACT FROM AUTHOR]

The magnificence of Bali makes this city famous as the world paradise among travellers. Its natural beauty emerges from its landscape, condensed culture and the local community. In southern Bali, the tranquil sandy beaches and karst landscapes attract few tourists, whereas their well-preserved sites store appealing facets of geological phenomena, heritage and tourism which differ to other tourism spots in Bali. This study aims to promote geotourism of Nusa Dua and Nusa Penida in Southern Bali with regards to the geological aspect of carbonate development, bioclastic sedimentation, tidal and wave abrasion, karstification, the emergence of freshwater spring on the sandy beaches and the dissemination of vertebrate fossil in the underwater cave. Geological observation is carried out to investigate karst and beaches morphologies, the geometry of reef carbonate and its karstification proce ss as well as the constituent of abundant white-sand sediments. The collected samples of sands and rocks from 4 sampling sites were analyzed using petrography analysis to identify the rock types and sand composition, while laser diffraction particle size is used to indicate the size distribution and how intense the winnowing process occurred. As a result, the existence of carbonate outcrops in Nusa Dua and Nusa Penida beaches is caused by tectonic uplift that elevates the pre-existing coral reef from shallow marine into the surface. In the surface, the reef carbonate underwent dissolution and karstification, which generated cave or other unique geometry. The discovery of vertebrate fossils in the underwater cave of the Stiva cave, Nusa Penida, reveals that this cave became a shelter for prehistoric human before it was inundated by seawater after the last maximum glaciation. Subsequently, reef carbonate growths perpetually to compensate the sea-level rise, uplifted again to surface and karstified until the present time. Another interesting object is the presence of nearshore groundwater seepage that discharges from a porous well rounded-sandy materials. It is assumed that the unconfined groundwater less firmly compresses the seawater when passing the maximum tidal level. These fascinating geological phenomena should be introduced to the visitors to educate them about the significance of preserving the geological landscape and environment. [ABSTRACT FROM AUTHOR]