Theory K
Mostrando 13-24 de 446 artigos, teses e dissertações.
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13. DELINEATION OF HOMOGENEOUS ZONES BASED ON GEOSTATISTICAL MODELS ROBUST TO OUTLIERS
RESUMO Diversas pesquisas utilizam medidas de condutividade elétrica aparente do solo (CEa) como indicador da variabilidade espacial de atributos físico-químicos existentes no campo de produção. Com base nestas medidas, zonas de manejo (ZM) são delineadas para aperfeiçoamento da gestão agrícola. Entretanto, estas amostras têm apresentado presença
Rev. Caatinga. Publicado em: 18/07/2019
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14. EXTRACTION OF BIOACTIVE COMPOUNDS OF LEAVES OF Duguetia furfuracea (ANNONACEAE) USING GREEN AND ORGANIC SOLVENTS
ABSTRACT Duguetia furfuracea (Annonaceae) is a shrub found in the Brazilian Cerrado that is used in popular medicine as an antirheumatic, for wound healing, treatment of kidney pain and against pediculosis. The aim of this study was to analyze the extraction of leaves of Duguetia furfuracea, using supercritical CO2, ethanol and hexane as solvents. For the su
Braz. J. Chem. Eng.. Publicado em: 15/07/2019
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15. Dehydration of infrared ginger slices: heat and mass transfer coefficient and modeling
RESUMO A desidratação de produtos vegetais prolonga sua vida útil e reduz sua massa e volume, o que aumenta a eficiência de transporte e armazenamento e agrega valor aos alimentos. No entanto, é um processo intensivo em energia e tempo, tornando necessária a busca por tecnologias mais eficientes. Diante do exposto, objetivou-se investigar o processo de
Ciênc. agrotec.. Publicado em: 02/05/2019
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16. MOLECULE DESIGN AND PROPERTIES OF CYCLIC ENERGETIC MATERIALS BASED ON NITROGUANIDINE AND 1,1-DIAMINO-2,2-DINITROETHENE
A series of cyclic energetic derivatives based on nitroguanidine and 1,1-diamino-2,2-dinitroethene were theoretically designed. The spatial structures, infrared spectrometry, heats of formation, electronic structures, detonation properties, and thermal stabilities of these designed compounds were fully investigated by density functional theory. It is found t
Quím. Nova. Publicado em: 2019-02
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17. Kinetic parameters of lipid oxidation in third generation (3G) snacks and its influence on shelf-life
Abstract In food systems, lipid oxidation is one of the most important factors affecting food quality, nutrition, safety, color and consumer acceptance. The objective of this study was to determine the kinetic parameters of lipid oxidation and its influence in the shelf life of third generation (3G) snacks stored in three types of packaging (polyethylene, p
Food Sci. Technol. Publicado em: 07/01/2019
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18. THEORETICAL STUDIES ON TRIACETONETRIPEROXIDE (TATP) DERIVATIVES TO IMPROVE THEIR PERFORMANCE
Density functional theory (DFT) methods are used to study on TATP derivatives at DFT-B3LYP/6-311++G (d, p) level to improve TATP’s performance. The derivatives are 3,6,9-trimethyl-3,6,9-tris(trifluoromethyl)-1,2,4,5,7,8-hexaoxonane (TATP3F), 3,6,9-trimethyl-3,6,9-tris(nitromethyl)-1,2,4,5,7,8-hexaoxonane (TATPNO2) and (3,6,9-trimethyl-1,2,4,5,7,8-hexaoxona
Quím. Nova. Publicado em: 2019-01
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19. Kinetic parameters of lipid oxidation in third generation (3G) snacks and its influence on shelf-life
Abstract In food systems, lipid oxidation is one of the most important factors affecting food quality, nutrition, safety, color and consumer acceptance. The objective of this study was to determine the kinetic parameters of lipid oxidation and its influence in the shelf life of third generation (3G) snacks stored in three types of packaging (polyethylene, p
Food Sci. Technol. Publicado em: 20/12/2018
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20. Effect of Thermo-Mechanical Treatments on the Microstructure and Mechanical Properties of the Metastable β-type Ti-35Nb-7Zr-5Ta Alloy
In this work, theoretical composition design and thermo-mechanical treatments were combined in order to improve the mechanical compatibility of a biomedical β-type titanium alloy. By applying a composition design theory, cold rolling and low temperature aging, a metastable β-type Ti-35Nb-7Zr-5Ta (wt%) alloy with an elastic modulus of 47 GPa and a yield str
Mat. Res.. Publicado em: 29/10/2018
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21. Modeling of stem form and volume through machine learning
Abstract Taper functions and volume equations are essential for estimation of the individual volume, which have consolidated theory. On the other hand, mathematical innovation is dynamic, and may improve the forestry modeling. The objective was analyzing the accuracy of machine learning (ML) techniques in relation to a volumetric model and a taper function f
An. Acad. Bras. Ciênc.. Publicado em: 18/10/2018
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22. An Examination of the Prediction of Hydrate Formation Conditions in the Presence of Thermodynamic Inhibitors
Abstract Gas hydrates are crystalline compounds, solid structures where water traps small guest molecules, typically light gases, in cages formed by hydrogen bonds. They are notorious for causing problems in oil and gas production, transportation and processing. Gas hydrates may form at pressures and temperatures commonly found in natural gas and oil product
Braz. J. Chem. Eng.. Publicado em: 2018-01
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23. Conformational Analysis, Experimental and GIAO-DFT 13C NMR Chemical Shift Calculation on 2’-Hydroxy-3,4,5-trimethoxy-chalcone
In this paper we investigated the ability of the GIAO-mPW1PW91/6-31G(d)//mPW1PW91/6-31G(d) level of theory to predict the 13C nuclear magnetic resonance (NMR) chemical shifts of the 2’-hydroxy-3,4,5-trimethoxy-chalcone molecule. Two different approaches were used. First: the absolute shieldings σ for all carbon atoms in each geometrically optimized confor
J. Braz. Chem. Soc.. Publicado em: 2017-11
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24. DRYING KINETICS OF NIGER SEEDS
ABSTRACT: The objectives of this study were to describe the process of drying niger seeds through the fitting of different mathematical models to the experimental drying data, to select the best model that represents the phenomenon, and to determine the diffusion coefficients and thermodynamic properties of the product. Seeds with an initial moisture content
Eng. Agríc.. Publicado em: 2017-08