Management of Brazilian hardwood species (Jatoba and Garapa) wood waste biomass utilization for energy production purposes

ArticleIn the Federative Republic of Brazil, Jatoba ( Hymenaea courbaril ) and Garapa ( Apuleia leiocarpa ) trees are intensively harvested . The yield of one log is approximately 45 – 55%, which indicates a great amount of produced wood waste biomass.Present research monitored the suitability of wood waste biomass from Jatoba and Garapa trees for bio – briquette for solid biofuel production. The research was focused on chemical parameters, and energ y potential of such biomass kinds. Jatoba wood waste biomass was used for the production of bio – briquette fuel and its final mechanical quality was investigated by determination of their mechanical quality indicators. Results of chemical analysis (in wet b asis) exhibited great level of ash content in case of both species ( Jatoba – 0.31%, Garapa – 3.02%), as well as high level of energy potential; net calorific value equal to 18.92 MJ kg – 1 for Jatoba and to 18.39 5 MJ kg – 1 for Garapa. Analysis of elementary composition proved following levels of oxygen content: J atoba – 41.10%, Garapa – 39.97 %. Mechanical analysis proved bio – briquette samples volume density ρ equal to 896.34 kg m – 3 which indicated quality bio – briquette fuel , while the level of rupture force R F occurred at a lower level – 47.05 N mm – 1 . Most important quality indicator, the mechanical durability DU, unfortunately, occurred at a lower level; DU = 77.6% compared to the minimal level of bio – briquette fuels intended for commercial sales which must be > 90%. Overall analysis proved materials suitability for energy generation purpose with certain limitations which can improve by changing production parameters of briquetting

Agricultural residues in Indonesia and Vietnam and their potential for direct combustion: with a focus on fruit processing and plantation crops

ArticleEnergy consumption in Indonesia and Vietnam has grown rapidly in recent decades. To meet the energy needs of both countries, a higher utilisation of waste biomass sources may represent an adequate solution. Investigated samples represent major crop residues (waste biomass) originating mainly from the agriculture sector of the selected countries. Herbaceous waste biomass from Indonesia is, namely, cassava stems and root peelings ( Manihot esculenta ), coffee leaves ( Coffea arabica ), cacao leaves ( Theobroma cacao ), banana leaves ( Musa acuminata ), bamboo leaves ( Bambusoideae spp.) and aloe vera leaves ( Aloe vera ). Furthermore, fruit and aquatic waste biomass originating from Vietnam is, specifically, sugarcane bagasse ( Saccharum officinarum ), durian peelings ( Durio zibethinus ), rambutan peelings ( Nephelium lappaceum ), banana peelings ( Musa acuminata ), water milfoil ( Myriophyllum spicatum ) and water hyacinth ( Eichhornia crassipes ). All mentioned types of waste biomass were subjected to proximate and calorimetric analysis: moisture, ash and volatile matter contents (%) and higher and lower heating values (MJ kg – 1 ). Obtained values indicated the highest level of ash content in fruit bioma ss samples in the case of sugarcane bagasse (0.84%), in herbaceous biomass in the case of cassava stems (3.14%) and in aquatic biomass in the case of water hyacinth (14.16%). The highest levels of lower heating values were achieved by following samples (be st samples from each biomass type): cassava stems (17.5 MJ kg – 1 ); banana peelings (17.3 MJ kg – 1 ) and water hyacinth (12.8 MJ kg – 1 ). The overall evaluation of all observed samples indicated that the best suitability for energy utilisation by direct combusti on of investigated representatives is fruit waste biomass, followed by herbaceous waste biomass and then aquatic waste biomass

Optimal Strategies in Infinite-state Stochastic Reachability Games

We consider perfect-information reachability stochastic games for 2 players on infinite graphs. We identify a subclass of such games, and prove two interesting properties of it: first, Player Max always has optimal strategies in games from this subclass, and second, these games are strongly determined. The subclass is defined by the property that the set of all values can only have one accumulation point -- 0. Our results nicely mirror recent results for finitely-branching games, where, on the contrary, Player Min always has optimal strategies. However, our proof methods are substantially different, because the roles of the players are not symmetric. We also do not restrict the branching of the games. Finally, we apply our results in the context of recently studied One-Counter stochastic games