Chemical Analysis
Mostrando 13-24 de 4384 artigos, teses e dissertações.
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13. Physical and chemical characteristics and analysis of plant substrate
Resumo O cultivo em ambiente protegido e recipiente culminou com a necessidade da utilização de substratos com características fisico-químicas específicas; assumindo um papel fundamental no cultivo de plantas hortícolas. Assim, o objetivo foi descrever as principais característica fisico-químicas de substratos e as principais metodologias para a sua
Ornamental Horticulture. Publicado em: 2022
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14. Spectroscopic techniques combined with chemometrics to study organic matter in tropical soils with different degrees of pedogenetic evolution
Understanding of the organomineral interactions in soil can elucidate the humic substances (HS) formation and the humification process. This study aimed to structurally characterize the humic acids (HA) formed in tropical soils with different pedogenesis degrees. The HA fraction was extracted from soil samples in the superficial horizons of an Inceptisol and
Química Nova. Publicado em: 2022
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15. Correlation analysis of Trial of Org 10172 in acute stroke treatment classification and National Institutes of Health Stroke Scale score in acute cerebral infarction with risk factors
SUMMARY OBJECTIVE: The aim of this study was to investigate the correlation between the Trial of Org 10172 in acute stroke treatment classification and the National Institutes of Health Stroke Scale score of acute cerebral infarction as well as acute cerebral infarction's risk factors. METHODS: The clinical data of 3,996 patients with acute cerebral infarc
Revista da Associação Médica Brasileira. Publicado em: 2022
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16. Bioactive compounds, bromatological and mineral characterization of blackberries in a subtropical region
ABSTRACT Given the above, the objective of this study was to evaluate the bromatological, mineral and bioactive compounds of blackberry grown in a subtropical region. Blackberries fruits (Rubus sp.), Grown in an orchard of Unioeste, Campus Marechal Cândido Rondon (Paraná, Brazil), were used. Immediately after harvest, the fruits were taken to the Food Tech
Revista Ceres. Publicado em: 2022
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17. Thermostimulated crystal structure transformation of the polymineral clay submicron particles
Abstract Changes in the structure of phyllosilicate microparticles of submicron fractions of polymineral clay with an average size of 290 nm, as well as changes in the positions of impurity ions of transition metals in the crystal lattice, were studied by X-ray diffraction analysis, Fourier transform infrared spectroscopy, and high-resolution electron parama
Cerâmica. Publicado em: 2022
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18. VIBRATION CHARACTERISTICS, CHEMICAL BONDS AND WEAK INTERACTIONS OF 4- AND 5-HYDROXYSALICYLIC ACID INVESTIGATED BY TERAHERTZ SPECTROSCOPY AND DENSITY FUNCTIONAL THEORY
The terahertz (THz) absorption spectra of 4- and 5-hydroxysalicylic acid were measured by terahertz time-domain spectroscopy (THz-TDS) in the range of 0.4-2.8 THz. The unit cells of both were calculated by density functional theory (DFT), and the theoretical simulation and experimental data were basically in agreement. To further interpret the origin of the
Química Nova. Publicado em: 2022
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19. Biogenic synthesis of silver nanoparticles from thyme extract for functionalization of a bioactive glass produced from rice husk ash
Abstract The rice husk, agro-industrial residue, stands out for having silica, the main oxide former of the bioactive glass. To avoid contamination in this biomaterial, substances with bactericidal properties, like silver can be incorporated. Thus, the objective of this work is the synthesis of silver nanoparticles to functionalize a bioactive glass synthesi
Cerâmica. Publicado em: 2022
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20. 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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21. Identifying conceptions of the covalent bond: an analysis from a systematic review
The covalent bond is a classical topic in science education because it is fundamental to a considerable number of other concepts and by its ability to interpret several chemical phenomena. However, the process of learning this concept presents some difficulties discussed here. This article brings together the conceptions related to the covalent bond, identif
Química Nova. Publicado em: 2022
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22. 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
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23. ROBÓTICA EDUCACIONAL, ENSINO DE QUÍMICA E APRENDIZAGEM COOPERATIVA: UMA PROPOSTA PARA O CURSO DE ENSINO SUPERIOR EM ENGENHARIA CIVIL
Students, generally, are afraid of studying chemistry because they understand that it is a very complex area of knowledge and that it doesn’t has use in daily lives and in intended profession, which is a problem we identified in a Civil Engineering course. With this, we proposed a project in this course, based on educational robotics and educational cooper
Química Nova. Publicado em: 2022
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24. Simultaneous GC-NCI-MS Determination of Persistent Organic Pollutants and Current-Use Pesticides in Breast Milk Samples
To preserve human health, persistent organic pollutants (POPs) and current-use pesticides (CUPs) should be monitored in fatty tissues, including breast milk. Therefore, this study aimed to optimize sample preparation conditions using a 32 factorial design for the determination of POPs and CUPs by gas chromatography coupled to mass spectrometry with negative
Journal of the Brazilian Chemical Society. Publicado em: 2022