Atmospheric Composition
Mostrando 1-12 de 115 artigos, teses e dissertações.
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1. Chemical Constituents and Cytotoxic Activity of Rhinella jimi (Anura: Bufonidae)
Rhinella jimi toads (Stevaux, 2002) belong to the Bufonidae family, are endemic in the Brazilian Northeast and are commonly found during rainy periods. In general, amphibians of this family have in their poisons different metabolites that show a diversity of pharmacological activities. The isolation and identification of these compounds are of great importan
J. Braz. Chem. Soc.. Publicado em: 2021-05
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2. GASES DE NITROGÊNIO REATIVO COMO PRECURSORES DO AEROSSOL ATMOSFÉRICO: REAÇÕES DE FORMAÇÃO, PROCESSOS DE CRESCIMENTO E IMPLICAÇÕES AMBIENTAIS
The increased emissions of reactive nitrogen gases from anthropogenic sources to the atmosphere has been pointed out as responsible for triggering a series of environmental problems at the local, regional, and global scale. Among the many consequences associated with the excess of reactive nitrogen in the environment is the increase of atmospheric aerosol fo
Quím. Nova. Publicado em: 2021-04
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3. AVALIAÇÃO QUÍMICA DE LENHOS CARBONIZADOS DE Araucaria columnaris SOB DIFERENTES CONCENTRAÇÕES DE OXIGÊNIO COMO COMPARATIVO DE ANÁLISE DE charcoal FÓSSIL
In the face of environmental changes concerns, the study of climate change becomes essential to understand the life trajectory of planet earth. For this purpose, this work seeks to understand climate change and fluctuations in the amount of atmospheric oxygen across geological ages, carbonizing the Araucaria columnaris wood in varying oxygen concentrations,
Quím. Nova. Publicado em: 2021-03
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4. Pyrolysis of the Caupi Bean Pod (Vigna unguiculata): Characterization of Biomass and Bio-Oil
The use of agricultural residues for the production of bio-oil is an important alternative to the use of fossil fuels. In this study, the Caupi bean pod (Vigna unguiculata) was characterized and used as biomass in the production of bio-oil. This biomass was evaluated in terms of physicochemical, morphological (scanning electron microscopy (SEM)), and thermal
J. Braz. Chem. Soc.. Publicado em: 2020-06
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5. Assessment of Atmospheric PM10 Pollution Levels and Chemical Composition in Urban Areas near the 2016 Olympic Game Arenas
Coarse particulate matter (PM10) concentrations and chemical composition were monitored from 2014 to 2017 at three sampling sites in the Metropolitan Region of Rio de Janeiro, namely Botafogo, Gávea, and Gericinó. All sites are located close to the 2016 Olympic Game arenas. The average annual PM10 concentrations were above the limits recommended by the Wor
J. Braz. Chem. Soc.. Publicado em: 2020-05
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6. Study of the Effect of Inhibitors Solutions on the Chemical Composition of Waxes by Rheology Tests and High Resolution Mass Spectrometry
Wax deposit is of a great concern in the petroleum industry and causes partial or total blockage of the pipelines. In this work, four Brazilian crude oils (P1-P4) and five inhibitors solutions (I1-I5) were used associating rheology results to understand, at a molecular level, the characteristics of the saturated fractions by high-resolution mass spectrometry
J. Braz. Chem. Soc.. Publicado em: 2020-04
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7. How increased atmospheric carbon dioxide and ‘The Law of the Minimum’ are contributing to environmental obesity
Resumo Justus von Liebig observou que era possível aumentar a produção agrícola adicionando pequenas quantidades de nitrogênio (N), fósforo (P) e potássio (K) aos solos. Essa descoberta levou a mais recente revolução agrícola. Contudo, uma vez que a maioria das plantas e microrganismos podem ser não-homeostáticos em relação a composição quím
Acta Limnol. Bras.. Publicado em: 28/11/2019
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8. Effect of Curing Temperature, Activator Solution Composition and Particle Size in Brazilian Fly-Ash Based Geopolymer Production
The geopolymer binder is a relatively new class of inorganic binding material of elevated mechanical strength and good chemical properties. This can be produced using clay minerals or byproducts of the industrial processes, such as metakaolin, fly-ash and blast furnace slag. In this work, geopolymers were produced by alkaline activation of a Brazilian fly-as
Mat. Res.. Publicado em: 22/08/2019
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9. EVALUATION OF DISTILLATION CURVES FOR BIO-OIL OBTAINED FROM THERMAL CRACKING OF WASTE COOKING OIL
ABSTRACT Bio-oil obtained from thermal cracking of waste cooking oil (WCO) is a complex mixture of different chemical compounds and, like crude oil, it is composed mainly of hydrocarbons. The large number of compounds in bio-oil leads to complex and expensive methods for its properties determination. In this study, the distillation curves were constructed fo
Braz. J. Chem. Eng.. Publicado em: 15/07/2019
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10. Experimental Investigation on the Evolution of Hydrogen in Steel during the Electroslag Remelting Process
Hydrogen, which is a harmful element, has a great effect on the mechanical properties of steel, should be removed during the steel manufacture process. The evolution of hydrogen content in steel during electroslag remelting process is experimentally investigated. The results show that during the electroslag remelting process, the hydrogen content in steel fi
Mat. Res.. Publicado em: 13/06/2019
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11. Investigação da corrosão eletrolítica em telhas de aço recobertas com zincalume
RESUMO As telhas de aço usadas em galpões de fazendas expostas às intempéries ficam vulneráveis à degradação. A corrosão surge devido à diferença de potencial elétrico entre a superfície metálica e o meio, levando a um carregamento elétrico dessa superfície. Elas então necessitam da proteção de um recobrimento anticorrosivo, cujo objetivo
Matéria (Rio J.). Publicado em: 20/05/2019
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12. DESTILAÇÃO ATMOSFÉRICA DO BIODIESEL DERIVADO DO ÓLEO DE MACAÚBA OU DO PALMISTE PARA OBTENÇÃO DA FRAÇÃO DE ÉSTERES LEVES PARA USO COMO COMBUSTÍVEL DE AVIAÇÃO
The production of methyl esters via transesterification reaction of triacylglycerides of macaúba and palm kernel oils, with subsequent atmospheric distillation and separation of six fractions of the produced biodiesel, corresponding to 60% of its initial volume, is reported. The composition in esters of the produced biodiesel, its fractions and remaining re
Quím. Nova. Publicado em: 2019-02