POTENTIAL OF MACAUBA EPICARP (Acrocomia aculeata (Jacq.) Lodd. ex Martius) FOR BRIQUETTES PRODUCTION

Briquetting is a form to aggregate value in the biomass production chain, to re-use sustainably waste and to provide high-quality solid biofuels, as well as to enable the development of the energy market. The aim of this study was to evaluate the potential of the production of briquettes from epicarp waste of macauba fruit and verify the influence of different temperatures and compaction pressures on the chemical, physical, and mechanical characteristics of the briquettes. The epicarp was reduced to particles and, then classified, dried, and characterized for their physical and chemical properties. The briquettes were produced by using compression pressures of 62, 83, and 103 bar and temperatures of 90 and 120 °C. The effect of these factors upon the variables studied was verified through regression analysis. The increase of pressure and temperature contributed to greater mass loss of the briquettes. Apparent density and energy density increased due to temperature rise. High values of energy density were obtained, which demonstrates the potential of the macauba fruit epicarp to produce briquettes for generation of thermal energyBriquetting is a form to aggregate value in the biomass production chain, to re-use sustainably waste and to provide high-quality solid biofuels, as well as to enable the development of the energy market. The aim of this study was to evaluate the potential of the production of briquettes from epicarp waste of macauba fruit and verify the influence of different temperatures and compaction pressures on the chemical, physical, and mechanical characteristics of the briquettes. The epicarp was reduced to particles and, then classified, dried, and characterized for their physical and chemical properties. The briquettes were produced by using compression pressures of 62, 83, and 103 bar and temperatures of 90 and 120 °C. The effect of these factors upon the variables studied was verified through regression analysis. The increase of pressure and temperature contributed to greater mass loss of the briquettes. Apparent density and energy density increased due to temperature rise. High values of energy density were obtained, which demonstrates the potential of the macauba fruit epicarp to produce briquettes for generation of thermal energy

POTENCIAL ENERGÉTICO DOS RESÍDUOS DO FRUTO DA MACAÚBA E SUA UTILIZAÇÃO NA PRODUÇÃO DE CARVÃO VEGETAL

The use of biomass for energy purposes has been highlighted in as a way to reduce dependence on non-renewable energy sources. Macaw palm, Acrocomia aculeata (Jacq.) Lodd. ex Martius, is an arborescent palm and has a high energy potential from the fruit processing. The aim of this study was to characterize the macaw palm residues after the fruit processing to evaluate its use "in natura" and as charcoal. The endocarp showed higher fixed carbon content, heating value and bulk density compared with other residues and lower ashes content. The heating value of endocarp charcoal was the highest, whereas the volatile matter levels of epicarp charcoal showed higher results. All evaluated residues from the macaw palm fruit processing have potential in power generation, especially the endocarp and the epicarp. The endocarp charcoal has suitable characteristics as source of energy and as a reductant.O uso da biomassa para fins energéticos tem sido destaque como forma de reduzir a dependência energética de fontes não renováveis. A macaúba, espécie Acrocomia aculeata (Jacq.) Lodd. ex Martius, é uma palmeira arborescente. Possui um grande potencial energético a partir do processamento de seus frutos. O objetivo desse trabalho foi caracterizar os resíduos da macaúba após o processamento dos frutos, a fim de avaliar a sua utilização in natura e como carvão vegetal. O endocarpo apresentou teor de carbono fixo, poder calorífico e densidade a granel superiores, quando comparado aos demais resíduos e menores teores de cinza. O poder calorífico do carvão do endocarpo foi superior, enquanto que os teores de materiais voláteis do carvão do epicarpo apresentaram os maiores resultados. Todos os resíduos avaliados do processamento do fruto da macaúba têm potencial na geração de energia, especialmente o endocarpo e o epicarpo. O carvão do endocarpo possui características adequadas para sua utilização como fonte de energia e como redutor

ENERGY POTENTIAL OF THE MACAW PALM FRUIT RESIDUES AND THEIR USE IN CHARCOAL PRODUCTION

O uso da biomassa para fins energ\ue9ticos tem sido destaque como forma de reduzir a depend\ueancia energ\ue9tica de fontes n\ue3o renov\ue1veis. A maca\ufaba, esp\ue9cie Acrocomia aculeata (Jacq.) Lodd. ex Martius, \ue9 uma palmeira arborescente. Possui um grande potencial energ\ue9tico a partir do processamento de seus frutos. O objetivo desse trabalho foi caracterizar os res\uedduos da maca\ufaba ap\uf3s o processamento dos frutos, a fim de avaliar a sua utiliza\ue7\ue3o in natura e como carv\ue3o vegetal. O endocarpo apresentou teor de carbono fixo, poder calor\uedfico e densidade a granel superiores, quando comparado aos demais res\uedduos e menores teores de cinza. O poder calor\uedfico do carv\ue3o do endocarpo foi superior, enquanto que os teores de materiais vol\ue1teis do carv\ue3o do epicarpo apresentaram os maiores resultados. Todos os res\uedduos avaliados do processamento do fruto da maca\ufaba t\ueam potencial na gera\ue7\ue3o de energia, especialmente o endocarpo e o epicarpo. O carv\ue3o do endocarpo possui caracter\uedsticas adequadas para sua utiliza\ue7\ue3o como fonte de energia e como redutor.The use of biomass for energy purposes has been highlighted in as a way to reduce dependence on nonrenewable energy sources. Macaw palm, Acrocomia aculeata (Jacq.) Lodd. ex Martius, is an arborescent palm and has a high energy potential from the fruit processing. The aim of this study was to characterize the macaw palm residues after the fruit processing to evaluate its use \u201cin natura\u201d and as charcoal. The endocarp showed higher fixed carbon content, heating value and bulk density compared with other residues and lower ashes content. The heating value of endocarp charcoal was the highest, whereas the volatile matter levels of epicarp charcoal showed higher results. All evaluated residues from the macaw palm fruit processing have potential in power generation, especially the endocarp and the epicarp. The endocarp charcoal has suitable characteristics as source of energy and as a reductant

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements