Acetylene
Mostrando 1-12 de 431 artigos, teses e dissertações.
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1. Antileishmanial Acetylene Fatty Acid and Acetogenins from Seeds of Porcelia macrocarpa
In the present work five acetylene derivatives (1-5), including three unknowns (1, 3 and 4), were isolated from seeds of Porcelia macrocarpa (Annonaceae). The structures of isolated compounds were determined as docos-13-yn-21-enoic acid (1), 3-hydroxy-4-methylene-2-(eicos-11’-yn-19’-enyl)but-2-enolide (2), 3-hydroxy-4-methylene-2-(octadec-9’-yn-17’-e
J. Braz. Chem. Soc.. Publicado em: 2021-02
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2. Free-living diazotrophs drive castor bean nitrogen input in tropical semiarid soils
RESUMO: Existem poucos estudos sobre a diversidade microbiana em solos de mamona no ambiente semiárido tropical. Os produtos de mamona têm sido amplamente utilizados em todo o mundo e justificam a importância comercial da ricinocultura no semiárido nordestino brasileiro. Como não há qualquer tipo de fertilização, ou manutenção de resíduos da cult
Cienc. Rural. Publicado em: 02/12/2019
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3. PHNSNCL4-N SUPPORTED ON ACTIVATED CARBON AS NOVEL TIN-BASED CATALYSTS FOR ACETYLENE HYDROCHLORINATION
In this work, a series of PhnSnCl4-n (n = 1, 2, 3, and 4) based catalysts were prepared by incipient wetness impregnation using activated carbon (AC) as support and triphenyltin chloride (Ph3ClSn) and tin(IV) chloride (SnCl4) as Sn precursors. The obtained catalysts were systematically characterized by X-ray diffraction (XRD), N2 physisorption, Scanning elec
Quím. Nova. Publicado em: 26/08/2019
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4. Tribological behavior of hydrogenated W-C/a-C:H coatings deposited by three different sputtering techniques
Abstract The evolution of structure, mechanical properties and friction behavior of DC magnetron sputtered (DCMS), high power impulse magnetron sputtered (HiPIMS) and high target utilization sputtered (HiTUS) W-C:H coatings was investigated as a function of the addition of acetylene and hydrogen into Ar atmosphere. The gradual addition of reactive gases caus
Cerâmica. Publicado em: 2019-01
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5. Evaluación del uso de acetileno como fuente de carbono en la carburización de aceros
ABSTRACT The effect of using acetylene as a carbon source in the gas carburization of AISI/SAE 8620 steel was evaluated in this work. For this purpose, a gaseous carburizing system was designed and manufactured with the following characteristics: controlled production of a carburant gaseous atmosphere, inert and hermetic isothermal reaction zone and carbon/o
Matéria (Rio J.). Publicado em: 19/07/2018
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6. Effect of Flame Spray Deposition Parameters on The Microstructure of Al2 O3 - 13 %TiO2 Coatings Applied Onto 7075 Aluminum Alloy
In this work, the effect of flame spraying parameters on physical, structural and microstructural characteristics of Al2O3 - 13 wt.% TiO2 (AT-13) coatings were studied. NiCrAl and AT-13 feedstock powders were used for spraying a bond coat (BC) and a top coat (TC), respectively, onto a 7075 aluminum alloy substrate. The effect of acetylene-to-oxygen ratio and
Mat. Res.. Publicado em: 10/07/2018
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7. THE SYMMETRY BREAKING PHENOMENON IN 1,2,3-TRIOXOLENE AND C2Y3Z2 (Z= O, S, Se, Te, Z= H, F) COMPOUNDS: A PSEUDO JAHN-TELLER ORIGIN STUDY
1,2,3-Trioxolene (C2O3H2) is an intermediate in the acetylene ozonolysis reaction which is called primary ozonide intermediate. The symmetry breaking phenomenon were studied in C2O3H2 and six its derivatives then oxygen atoms of the molecule are substituted by sulphur, selenium, tellurium (C2Y3H2) and hydrogen ligands are replaced with fluorine atoms (C2Y3F2
Quím. Nova. Publicado em: 2017-06
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8. O PARADIGMA DA ESTRUTURA DO DOADOR DE PRÓTON NA FORMAÇÃO DE LIGAÇÕES DE HIDROGÊNIO: COMPLEXO C2H2···6(HF)
The DFT, QTAIM, NBO and ChelpG methods were used in a theoretical study of structural parameters, vibration stretch modes and absorption intensities, electronic properties, molecular orbital analyses and molecular topography of the heptamer C2H2···6(HF) complex. One of the great aims concerns to the studying of the proton donor structure, which is conside
Quím. Nova. Publicado em: 2016-11
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9. Ampliação do uso da técnica de espectrometria de absorção atômica utilizando tubo metálico na chama para determinação de prata / Enlarging the use of thermospray flame furnace atomic absorption spectrometry for determination of silver
Thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) uses a metallic tube on the flame of the atomic absorption spectrometer. The sample is introduced in the tube by a ceramic capillary. In the development of this method, the parameters involved were studied and the optimal conditions consist of using air as carrier at 0.4 mL min, 200 mL of s
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/03/2012
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10. Teores de elementos tóxicos e micronutrientes em fertilizantes e corretivos comercializados no Nordeste do Brasil.
Heavy metals are chemical elements with a density greater than 6 g cm-3 and among these metals, there are toxic elements cadmium (Cd), lead (Pb) and chromium (Cr). In soil, the application of fertilizers and heavy metals can add as impurities constituents of these inputs, contributing to soil contamination. Several countries, including Brazil, regulate the c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/03/2011
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11. Enhanced electrochemical activity using vertically aligned carbon nanotube electrodes grown on carbon fiber
Vertically aligned carbon nanotubes were successfully grown on flexible carbon fibers by plasma enhanced chemical vapor deposition. The diameter of the CNT is controllable by adjusting the thickness of the catalyst Ni layer deposited on the fiber. Vertically aligned nanotubes were grown in a Plasma Enhanced Chemical Deposition system (PECVD) at a temperature
Materials Research. Publicado em: 26/08/2011
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12. Kinetics of oxyfuel gas cutting of steels
Oxyacetylene flame cutting is a relevant and widespread industrial process. The basic principles of the process lie in rapid high-temperature oxidation of the cut metal. The kinetics of the process depends, among other things, on the composition of the cut metal, the activity of the reactants. In this present work, a report of the role of carbon on the kinet
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011-06