Chemical Kinetics
Mostrando 13-24 de 436 artigos, teses e dissertações.
-
13. The influence of Cu content on high temperature corrosion behavior of heat - resistant molten salt steel
ABSTRACT This work studies the high temperature corrosion behavior of new heat-resistant steel with salt coating method of 75%Na2SO4+25%NaCl coating on the steel surface at 700ºC. The chemical composition of corrosion products and surface morphology of the corrosion layer were analyzed using X-ray diffractometer (XRD), scanning electron microscopy (SEM), en
Matéria (Rio J.). Publicado em: 16/09/2019
-
14. Drying Kinetics of Cecropia pachystachya Leaves
ABSTRACT The species Cecropia pachystachya has important medicinal purposes and its leaves have been used in pharmaceutical research, so the drying of this product may help maintaining its chemical properties and ensure safe storage. Thus, the objective of this study was to select mathematical models to represent the drying kinetics of Cecropia pachystachya
Floresta Ambient.. Publicado em: 05/09/2019
-
15. Geopropolis gel for the adjuvant treatment of candidiasis – formulation and in vitro release assay
ABSTRACT The geopropolis produced by the stingless bee Melipona subnitida (popularly called "jandaíra" in Brazil) is a mixture of resin, wax, and mud. This study analyzed the antifungal activity of the geopropolis extract from Candida spp., developed a gel formulation with this extract and analyzed the delivery of bioactives (kinetics release) in the formul
Rev. bras. farmacogn.. Publicado em: 26/08/2019
-
16. Adsorção do azul de metileno em serragem de Pinus elliottii (pinus) e Drepanostachyum falcatum (bambu)
RESUMO A cinética, o equilíbrio e os parâmetros termodinâmicos de adsorção foram investigados para a adsorção do corante azul de metileno (AM) por meio dos biossorventes Pinus elliottii (pinus) e Drepanostachyum falcatum (bambu). A cinética de adsorção foi descrita mais precisamente pelo modelo de pseudossegunda ordem, os dados de equilíbrio mono
Eng. Sanit. Ambient.. Publicado em: 15/08/2019
-
17. Avaliação e estabilidade da cor em filés de burriquete (Pogonias cromis) utilizando um sistema de visão computacional
Resumo A cor da superfície da carne é a primeira sensação que o consumidor percebe e utiliza como uma ferramenta para aceitar ou rejeitar um alimento. A medição e a avaliação da cor da carne podem também ser feitas por um indicador químico (metamioglobina) ou pela avaliação física, utilizando espaços da cor (a* e R). O objetivo deste trabalho f
Braz. J. Food Technol.. Publicado em: 13/06/2019
-
18. Effect of the Chemical Homogeneity of a Quenched and Tempered C-Mn Steel Pipe on the Mechanical Properties and Phase Transformations
Seamless steel pipes for application in the oil and gas industries are manufactured from quenched and tempered steel. Aiming to meet the required characteristics, it is necessary that the microstructure and the mechanical properties are homogeneous along the wall thickness of the pipes, which is even more critical for thick wall pipes. Considering the seamle
Mat. Res.. Publicado em: 03/06/2019
-
19. FOTOCATÁLISE MEDIADA POR TiO2 NO ESTADO NANOPARTICULADO: REVISÃO DA REATIVIDADE PELO CONCEITO DE TRAPS E ALGUMAS APLICAÇÕES EM QUÍMICA ANALÍTICA
TiO2 has been used as a white pigment and studied since the first decades of the XX century for the undesirable chalking of outdoor paintings exposed to sunlight. Since the first report of Honda and Fujishima (1972) of the water splitting by the harvesting of sunlight on a n-type single crystal TiO2 electrode, the engagement of researchers with the field has
Quím. Nova. Publicado em: 02/05/2019
-
20. COD removal from sucrose solution using hydrodynamic cavitation and hydrogen peroxide: a comparison between Venturi device and orifice plate
RESUMO O objetivo deste estudo foi comparar a eficiência de remoção de DQO de um Venturi e de uma placa de orifício. Adicionalmente, a otimização da pressão de entrada dos dispositivos, o estudo da cinética da degradação, e o efeito sinérgico resultante da combinação da cavitação e H2O2 foram realizados. Um aparato experimental em escala labo
RBRH. Publicado em: 28/02/2019
-
21. Retracción química de pastas de cemento con incorporación de metacaolín
Abstract This study shows the influence of partial replacement of Portland cement by metakaolin in the hydration reactions and chemical shrinkage of cementitious pastes. For this, pastes were prepared using metakaolin replacements of 5, 10 and 20% by mass, and a reference paste, using a constant water/solid ratio of 0,5. Chemical shrinkage was measured conti
Ambient. constr.. Publicado em: 2018-09
-
22. Kinetic and Thermodynamic Study in Pozzolanic Chemical Systems as an Alternative for Chapelle Test
Important properties in cementitious materials, such as concrete, are related to the presence of additives that influence the rigidity and the physical and chemical resistances. For the evaluation of the additive effectiveness, known as pozzolanic activity, a simple procedure, the Chapelle test, is commonly used, and it essentially consists in a reaction bet
Mat. Res.. Publicado em: 25/06/2018
-
23. SOLVENT SELECTION FOR CHEMICAL REACTIONS: AUTOMATED COMPUTATIONAL SCREENING OF SOLVENTS USING THE SMD MODEL
Finding the most efficient solvent for a chemical reaction can demand costly experimental procedure and the screening is usually limited to few solvents. The use of theoretical methods could accelerate the search for the best solvent, able to promote most effective kinetics and thermodynamics of a reaction. In this work, it was proposed an automated procedur
Quím. Nova. Publicado em: 2018-06
-
24. Characterization of Niobia-alumina Deposited by the Sol-gel Process on Carbon Steel
The precursor sols of Al2O3 and mixed NbxOy/Al2O3 oxides were synthesized by the sol-gel process using acetylacetone to control the reaction kinetics of the organometallic oxides in the mixture. The layers of the precursor sols of Al2O3 and NbxOy/Al2O3 were deposited on AISI steel 1020 by manual immersion (dip coating). The lyophilized sols were characterize
Mat. Res.. Publicado em: 16/04/2018