Estudo da decomposição térmica da madeira do cafeeiro / Study of the thermal decomposition of coffee wood

Considerando a necessidade de gestão adequada dos resíduos do cultivo e processamento do café, a energia presente na biomassa pode ser aproveitada através do processamento termoquímico do material para obtenção de produtos com maior valor energético ou matérias-primas químicas de valor agregado. Nesse sentido, o presente trabalho teve por objetivo estudar a decomposição termogravimétrica da madeira do cafeeiro em atmosferas inerte e oxidante, usando um DTG60H-SHIMADZU e aplicando as taxas de aquecimento de 10, 25 e 50 oC.min-1. A decomposição térmica da madeira do cafeeiro apresentou diferentes etapas: (I) em nitrogênio, foram secagem, pirolise ativa e carbonização; (II) em ar, foram secagem, pirólise ativa oxidativa e combustão do carvão formado na pirólise ativa oxidativa. Na análise em presença de ar, foi possível observar maiores taxas de reações, maior liberação de calor e baixa fração de material ao fim da análise. Os resultados obtidos contribuíram para uma melhor compreensão do comportamento de decomposição termoquímica da madeira do cafeeiro

Luminescent gold(III) thiolates: Supramolecular interactions trigger and control switchable photoemissions from bimolecular excited states

A new family of cyclometallated gold(III) thiolato complexes based on pyrazine-centred pincer ligands has been prepared, (C^Npz^C)AuSR, where C^Npz^C=2,6-bis(4-ButC6H4)pyrazine dianion and R=Ph (1), C6H4tBu-4 (2), 2-pyridyl (3), 1-naphthyl (1-Np, 4), 2-Np (5), quinolinyl (Quin, 6), 4-methylcoumarinyl (Coum, 7) and 1-adamantyl (8). The complexes were isolated as yellow to red solids in high yields using mild synthetic conditions. The single-crystal X-ray structures revealed that the colour of the deep-red solids is associated with the formation of a particular type of short (3.2–3.3 Å) intermolecular pyrazine⋅⋅⋅pyrazine π-interactions. In some cases, yellow and red crystal polymorphs were formed; only the latter were emissive at room temperature. Combined NMR and UV/Vis techniques showed that the supramolecular π-stacking interactions persist in solution and give rise to intense deep-red photoluminescence. Monomeric molecules show vibronically structured green emissions at low temperature, assigned to ligand-based 3IL(C^N^C) triplet emissions. By contrast, the unstructured red emissions correlate mainly with a 3LLCT(SR→{(C^Npz^C)2}) charge transfer transition from the thiolate ligand to the π⋅⋅⋅π dimerized pyrazine. Unusually, the π-interactions can be influenced by sample treatment in solution, such that the emissions can switch reversibly from red to green. To our knowledge this is the first report of aggregation-enhanced emission in gold(III) chemistry

Genetic isolation and morphological divergence of Black Sea bottlenose dolphins

The Black Sea is a semi-enclosed body of water that differs from the adjacent Mediterranean Sea in terms of its biodiversity, oceanographical and ecological characteristics. There is growing international concern about pollution in the Black Sea and other anthropogenic threats to its fauna. The bottlenose dolphin (Tursiops truncatus) is one of three species of cetaceans living in the Azov-Black Sea basin. Despite considerable research on bottlenose dolphins elsewhere, the extent of human impacts on the Black Sea populations is unknown. Previous attempts to award special conservation status to Black Sea cetaceans have failed specifically because policy makers have viewed their ecological and evolutionary uniqueness as equivocal. This study assessed divergence between Black Sea, Mediterranean Sea and Atlantic Ocean bottlenose dolphins for 26 cranial measurements (n = 75 adult bottlenose dolphin skulls) and mitochondrial DNA (n = 99 individuals). Black Sea bottlenose dolphins are smaller than those in the Mediterranean, and possess a uniquely shaped skull. As in a previous study, we found the Black Sea population to be genetically distinct, with relatively low levels of mtDNA diversity. Population genetic models suggest that Black Sea bottlenose dolphins have so little gene flow with the Mediterranean due to historical isolation that they should be managed separately

Improving MeSH Classification of Biomedical Articles using Citation Contexts

Medical Subject Headings (MeSH) are used to index the majority of databases gener-ated by the National Library of Medicine. Essentially, MeSH terms are designed to make information, such as scientific articles, more retrievable and assessable to users of systems such as PubMed. This paper proposes a novel method for automating the assignment of biomedical publications with MeSH terms that takes advantage of citation references to these publications. Our findings show that analysing the citation references that point to a document can provide a useful source of terms that are not present in the document. The use of these citation contexts, as they are known, can thus help to provide a richer docu-ment feature representation, which in turn can help improve text mining and information retrieval applications, in our case MeSH term classification. In this paper, we also explore new methods of selecting and utilising citation contexts. In particular, we assess the effect of weighting the importance of citation terms (found in the citation contexts) according to two aspects: i) the section of the paper they appear in, and ii) their distance to the citation marker

Increase of capacity in electric arc-furnace steel mill factories by means of a demand-side management strategy and ampacity techniques

EU Regional Development Fund (FEDER); Spanish Government R+D initiative RETOS-COLABORACION with references RTC-2015-3795-3 and RTC-2017-6782-3