Characterization
Mostrando 25-36 de 28801 artigos, teses e dissertações.
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25. DESENVOLVIMENTO DE ACESSÓRIO PORTÁTIL DE CONTROLE DE TEMPERATURA PARA MEDIDAS ESPECTROSCÓPICAS
Temperature is a natural phenomenon that may modify the structure of chemical compounds and hence their properties. We aimed to develop a simple portable system based on the Peltier principle for spectral characterization of compounds with temperature-dependent structure. The device was constructed and adapted to three pieces of equipment: X-ray diffractomet
Química Nova. Publicado em: 2022
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26. Per-Aqueous Liquid Chromatography for the Separation of Polar Compounds Preparation and Characterization of Poly(ethylene oxide co dimethylsiloxane) Based Stationary Phase
Poly(ethylene oxide-co-dimethylsiloxane) was thermally immobilized on silica particles-Si(PEO)-to separate small polar compounds with water-rich mobile phases. Poly(ethylene oxide-co-dimethylsiloxane) content on Si(PEO) stationary phase was optimized using a central composite design. Infrared spectroscopy, scanning electron microscopy, and thermogravimetric
Journal of the Brazilian Chemical Society. Publicado em: 2022
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27. Characterization of the cattle movement network in the state of Goiás, Brazil
RESUMO No presente estudo, foi caracterizada a rede de trânsito de bovinos no estado de Goiás, Brasil, durante o período de 2010 a 2016, identificando-se as áreas de maior fluxo e as finalidades do trânsito desses animais. Para isso, foi realizada uma análise dos dados referentes a 4.697.239 guias de trânsito animal (GTA), especificamente de bovinos,
Arquivo Brasileiro de Medicina Veterinária e Zootecnia. Publicado em: 2022
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28. Synthesis and characterization of α-SnWO4 powders obtained by microwave-assisted hydrothermal method
Abstract The structural, morphological, and optical properties of α-SnWO4 synthesized by microwave-assisted hydrothermal method at 150 °C for different times were investigated. XRD revealed the formation of the orthorhombic phase, without the presence of a secondary phase. The sample processed for 64 min showed a reduction in unit cell volume, suggesting a
Cerâmica. Publicado em: 2022
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29. Characterization of a complex carbonate-silicate apatite ore and its concentration by a two-stage anionic flotation method
Abstract A carbonate-silicate low weathering phosphate ore from an igneous origin deposit in Southeastern Brazil presents a challenge mainly for apatite flotation from its gangue minerals, calcite and dolomite, plus the presence of phlogopite, diopside, magnetite, richterite, ilmenite, vermiculite, quartz and many other minor impurities. Recently, selectivit
REM - International Engineering Journal. Publicado em: 2022
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30. Structural characterization of the stem cell wall lignin of Euterpe oleracea
Resumo Este trabalho teve como objetivo caracterizar a lignina na parede celular de Euterpe oleracea Mart. Foram adquiridas amostras de duas regiões da base da palmeira: região externa e região interna (OR e IR, respectivamente). A extração com solventes orgânicos e o tratamento com NaOH 1% foram realizados. O conteúdo de holocelulose, α-celulose e l
Ciência Florestal. Publicado em: 2022
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31. Evaluation of sediment contamination by urban sewage in a stretch of Capibaribe River, Pernambuco, Brazil
Anthropic activities are responsible for the increase in environmental contamination, especially in aquatic systems, demanding studies to assess and monitor contamination levels in different water bodies. We have done a chemical characterization of eleven sediments in order to evaluate the level of contamination by domestic sewage from the Capibaribe River,
Química Nova. Publicado em: 2022
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32. Microplastics in Latin America Ecosystems: A Critical Review of the Current Stage and Research Needs
The ubiquity of microplastics ecosystems has gained global attention. In this context, Latin America, which is responsible for 8% of the world’s consumption of plastic material and has a small recycling rate (4.5%), does not have enough data on microplastics contamination in its environmental matrices. This systematic review analyzed 196 studies from 16 te
Journal of the Brazilian Chemical Society. Publicado em: 2022
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33. Development of a Disposable Pipette Extraction Method Using Coffee Silverskin as an Adsorbent for Chromium Determination in Wastewater Samples by Solid Phase Extraction
A procedure using disposable pipette tips adapted for solid-phase extraction, known as DPX SPE, was used as an alternative way for the chromium determination in wastewater samples. DPX-SPE consists of a device which allows a dynamic contact between the sample and the solid-phase. A residue obtained from the processing of coffee beans, denominate coffee silve
Journal of the Brazilian Chemical Society. Publicado em: 2022
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34. Genetic variability in Capsicum spp. accessions through multicategorical traits
ABSTRACT Capsicum peppers originate from the American continent. Their culinary and medicinal potential, first exploited by indigenous peoples over 7000 years ago is vast, however more studies are needed. Despite the existence of germplasm banks that house hundreds of accessions of the genus, only a little of this diversity is seen in large markets. In this
Revista Ceres. Publicado em: 2022
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35. Thermal treatment of poultry litter: Part I. Characterization by immediate analysis and gravimetric yield
RESUMO A produção de biocarvão a partir de cama de aviário por meio de pirólise lenta é uma abordagem de valor agregado baseada na fazenda para reciclar o resíduo orgânico. Os experimentos foram conduzidos para examinar como os tratamentos térmicos afetaram a composição final do material carbonizado e pirolisado em relação à análise imediata e
Revista Brasileira de Engenharia Agrícola e Ambiental. Publicado em: 2022
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36. An alternative route to extract nickel and cobalt from non-commercial laterite ore
Abstract Laterite ores, which represent around two-thirds of nickel reserves, became an important source of nickel and cobalt metals. The objective of the present study was to investigate the efficiency of a hybrid route to extract nickel and cobalt present in a laterite ore sample which was not commercially attractive to be processed through the current rou
REM - International Engineering Journal. Publicado em: 2022