Experiments
Mostrando 13-24 de 29561 artigos, teses e dissertações.
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13. ON A NEW APPROACH TO PEIRCE’S THREE-VALUE PROPOSITIONAL LOGIC
Abstract In 1909, Peirce recorded in a few pages of his logic notebook some experiments with matrices for three-valued propositional logic. These notes are today recognized as one of the first attempts to create non-classical formal systems. However, besides the articles published by Turquette in the 1970s and 1980s, very little progress has been made toward
Manuscrito. Publicado em: 2022
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14. Fast Catalytic Pyrolysis of Tetradecanoic Acid: Formation of Ketones as Intermediate Compounds in the Production of Hydrocarbons
This work aimed to compare two different catalysts in the production of a long chain ketone, intermediate in the production of hydrocarbons, during pyrolysis of tetradecanoic acid as a model fatty acid. The studied variables were the temperature, 450 and 600 ºC, and catalysts, γ-Al2O3 and Nb2O5, the latter has never been studied under such conditions. Pyro
Journal of the Brazilian Chemical Society. Publicado em: 2022
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15. Influence of the Local Structure on the Photocatalytic Properties of Zinc Spinel Ferrite Nanoparticles
The correlation between iron distribution in octahedral or tetrahedral sites in synthetic magnetite and zinc spinel ferrites and their catalytic properties were investigated in this work. The zinc-doped nanomagnetites were prepared by co-precipitation method and annealed at 420 °C. X-ray diffraction, UV-Vis, X-ray absorption and 57Fe Mössbauer spectroscopi
Journal of the Brazilian Chemical Society. Publicado em: 2022
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16. Finite element computational development for thermo-mechanical analysis of plane steel structures exposed to fire
Abstract This article presents a numerical formulation based on finite element procedures for application in nonlinear thermo-mechanical analyses of steel planar structures under fire condition. The mechanical properties of structural elements degrade when subjected to high temperatures, resulting in significant reductions in strength and stiffness. Under th
REM - International Engineering Journal. Publicado em: 2022
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17. Direct onion sowing under soil tillage methods
ABSTRACT Onion production is conditioned to the adopted techniques during the cultivation. Sowing depth, soil preparation and cultivars are determinant factors for productivity to be increased. Two experiments were developed, the first with the objective of evaluating the effect of sowing depths and soil preparation methods on the germination and development
Revista Ceres. Publicado em: 2022
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18. DESIGN AND EXPERIMENT OF A SAFFLOWER PICKING ROBOT BASED ON A PARALLEL MANIPULATOR
ABSTRACT To mitigate the large demand for safflower picking labour and the low efficiency of manual picking, a safflower picking robot that is based on a parallel manipulator is designed. The whole robot mainly consists of a walking device, parallel manipulator device, vision device, picking device, filament collection device, control system, and motor drive
Engenharia Agrícola. Publicado em: 2022
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19. Temperatures and light regimes in the germination of Areca vestiaria and Areca triandra seeds
ABSTRACT Propagation of palm trees is mainly by seeds and, in general, germination is uneven and slow, caused by several factors, such as temperature and light. We aimed to evaluate the effect of different temperature conditions and light regimes in the germination of Areca vestiaria and Areca triandra seeds. Two experiments were carried. The experimental de
Revista Ceres. Publicado em: 2022
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20. ANALYSIS OF BENZODIAZEPINES IN PLASMA SAMPLES BY DLLME AND LC-DAD: CRITICAL ASPECTS, FLAWS AND ISSUES ENCOUNTERED - A DISCUSSION
Dispersive liquid-liquid microextraction (DLLME) is a fast and simple technique and applicable procedure for the analysis of xenobiotics in different biological matrices. We have developed a DLLME method for the determination of benzodiazepines in plasma samples using liquid chromatography-diode-array detection (LC-DAD). During method validation, relative st
Química Nova. Publicado em: 2022
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21. Control of leaf anthracnose of peach palm with fungicides: a valid strategy for seedling nurseries, but not for young plantations
ABSTRACT This work aimed to evaluate the efficacy of fungicides for controlling anthracnose (Colletotrichum gloeosporioides) on peach palm (Bactris gasipaesvar.gasipaes) seedlings in nursery beds and in newly planted peach palms in the field. The nursery experiment included two fungicide combinations: [thiophanate-methyl + chlorothalonil (TM + C) and pyraclo
Revista Ceres. Publicado em: 2022
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22. Zeólita NaA sintetizada sobre fibra de vidro como estratégia para otimização do abrandamento de águas duras
NaA ZEOLITE SYNTHESIZED OVER FIBERGLASS AS A STRATEGY FOR OPTIMIZING HARD WATER SOFTENING. Zeolite NaA has been successfully synthesized over glass fiber surface previously activated by alkaline treatment. By varying the time of the treatment and the amount of silica and alumina precursors used in the reaction mixture, a sample with higher zeolite concentrat
Química Nova. Publicado em: 2022
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23. Prospects for Developing Low-Cost Optical Fiber Sensors for Liquid-Liquid Interface Detection
Abstract This work examines the prospects of a low-cost retroreflection optical sensor system for detection of the interface between two immiscible liquids, for applications in oil separation tanks. The sensor in its simplest configuration comprises a bare fiber optic tip, cleaved at an angle of 90º relative to the longitudinal fiber axis. The device tested
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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24. Herbicides applied in pre and post-emergence to control Chamaesyce hirta
ABSTRACT In view of the increase in the infested areas and the difficulty in controlling Chamaesyce hirta (L.) Millsp (garden spurge) there is growing interest in identifying herbicides that can be applied in pre and post-emergence, helping to reduce infestation and to provide species control. The objective of this work was to evaluate efficient alternatives
Revista Ceres. Publicado em: 2022