
Sergio DUVOISIN JrUniversidade do Estado do Amazonas | uea · Escola Superior de Tecnologia
Sergio DUVOISIN Jr
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24
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Publications (24)
Extensive research in the last few decades has conclusively demonstrated the significant influence of experimental conditions, surfactants, and synthesis methods on semiconductors’ properties in technological applications. Therefore, in this study, the synthesis of molybdenum oxide (MoO3) was reported by the addition of 2.5 (MoO3_2.5), 5 (MoO3_5),...
In developing countries, such as Brazil, public policies for monitoring surface water quality are precarious. Although the country has legal norms that establish water quality parameters, and the Water Quality Index (WQI) is used as an assessment tool, the management of surface water is neglected in cities such as Manaus. The objective of this stud...
Yellow passion fruit peel and cupuaçu seeds are common wastes. Usually, they have few or no applications and are discarded, causing environmental pollution. To use them in a new way and reduce ecological pollution, we obtained the ash of yellow passion fruit peels by calcination. We characterized it using Fourier‐transform infrared spectroscopy wit...
Volatile isoprenoids regulate plant performance and atmospheric processes, and Amazon forests comprise the dominant source to the global atmosphere. Still, there is a poor understanding of how isoprenoid emission capacities vary in response to ecophysiological and environmental controls in Amazonian ecosystems.
We measured isoprenoid emission capac...
Significance
Unquantified intermediate-scale heterogeneity in VOC emissions over Amazonia may be a key contributor to the observed discrepancy between measured and modeled VOC concentrations, but in situ measurements for investigating the possibility have been lacking. The measurements presented herein quantify horizontal VOC concentration gradient...
Aims:
To evaluate the production of biosurfactants by fungi isolated from the Amazonian species Piper hispidum (Piperaceae), and to determine the physico-chemical properties of the crude biosurfactant obtained from the most promising fungi.
Methods and results:
A total of 117 endophytic fungi were isolated, and 50 were used to verify the product...
Peels from tucumã, a widely consumed fruit in the North of Brazil, were calcined at 800 °C and employed as heterogeneous catalyst in biodiesel synthesis. The catalyst characterization by FRXDO showed it was mostly composed of K, P, Ca, and Mg. The catalytic activity was evaluated by transesterification of soybean oil with methanol. The transesterif...
A extração sólido-líquido é um método comumente utilizado em indústrias de bebidas e alimentos para a obtenção de extratos de plantas ricos em compostos bioativos. Neste trabalho foi realizada a extração de cafeína a partir de sementes de guaraná (Paullinia cupana), estudando a influência dos fatores tempo, tamanho da partícula, temperatura e conce...
RESUMO-Produtos naturais são utilizados com diversas finalidades como, por exemplo, o controle de pragas. O óleo essencial da espécie Cymbopogon winteranius, conhecida como citronela vem sendo aplicado para este fim. Contudo, após a coleta do material vegetal, o processo de degradação das substâncias presentes no óleo tem início, sendo necessária a...
In order to use the residue from the beneficiation of Brazil nuts (Bertholletia excelsa HBK) as substrate in solid-sate fermentation (SSF), in this work, the production of cellulase and xylanase by the fungus Trametes sp. was investigated, using the residue as a carbon source. Employing a 2 4-1 fractional experimental design, the influence of subst...
Significance
For isolated regions of the planet, organic peroxy radicals produced as intermediates of atmospheric photochemistry have been expected to follow HO 2 rather than NO pathways. Observational evidence, however, has been lacking. An accurate understanding of the relative roles of the two pathways is needed for quantitative predictions of t...
Several plant species have been proposed as source of oil for the transesterification reaction that generates the mixture of esters known as biodiesel; this biofuel has been considered as an energetic solution to the political, economic and environmental problems related to the use of petroleum-based fuels. The biodiesel process produces, stoichiom...
Hydrogen bond energies of fifteen dimers were calculated using the large basis set 6-311++G(3df,3pd), at Hartree-Fock (HF) level including Møller-Plesset (MP2) calculations. The procedure for obtaining such energies were based on the dimer's energy rise provoked by increasing in intermolecular distance of the system component units. Deviations from...
In this study, 212 fungi were isolated from Amazon region plants, aiming to obtain mycelium bound-lipase-producing biocatalysts. These isolates were submitted to hydrolytic and synthetic activity assays. When submitted to the tributyrine substrate test, 87% of the isolates showed hydrolytic activity. Of these, 30% showed good growth in lipase induc...
The Ammonium Perfluorooctanoate/water (APFO/H2O) system was studied by ‘ab initio’ quantum computational methods at the HF/6-31+G level. In the first step the optimized geometry of the APFO and APFO ion (PFO−) were obtained and the microscopic parameters such as the molecular volume, area of polar head, length and the volume of the fluorocarbon cha...
The remarks of S. D. Bechtel, Jr., President, Bechtel Corporation, cover the total energy picture at the conference. In summing the energy demand/supply gap, he concludes that serious deficiencies in domestic energy supplies exist today and are growing rapidly; that adequate reserves of energy are located within the United States; that oil and gas...