Microwave Energy
Mostrando 13-24 de 97 artigos, teses e dissertações.
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13. Novel Drying Process Assisted by Microwave to Iron Ore Pelletizing
Drying has became critical to iron ore pellet production, due to increasing inability to withdrawal moisture from the green pellets, especially faced by goethitic iron ore producers. Most of the existing pelletizing furnaces do not support increase heating rates nor changes in furnaces length, without compromise pellet quality. The present study evaluates an
Mat. Res.. Publicado em: 06/09/2018
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14. Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion
In this paper, magnesium aluminate spinels were prepared by microwave-assisted combustion, using urea as fuel. In order to evaluate the effect of the urea excess used in the synthesis, its mass was added in a range of 1.0 to 2.5 times the stoichiometric amount required. The materials produced were characterized by TGA, FTIR, XRF, XRD, BET, SEM and TEM. The r
Mat. Res.. Publicado em: 23/10/2017
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15. QUALITY, PERFORMANCE ANALYSIS, MASS TRANSFER PARAMETERS AND MODELING OF DRYING KINETICS OF SOYBEAN
Abstract Different aspects of soybean drying such as energy and exergy analyses, quality, mass transfer parameters, and modeling of drying kinetics were investigated in a microwave dryer. Results showed that energy and exergy efficiency increased with increasing microwave power, while values of energy efficiency (33.70 to 66.0%) were higher than exergy effic
Braz. J. Chem. Eng.. Publicado em: 2017-01
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16. Determination of Elemental Impurities in Acyclovir Ointment and Raw Materials Using Microwave Acid Digestion (MW-AD) and ICP-MS
Inorganic elements present in pharmaceutical products were determined by inductively coupled plasma-mass spectrometer (ICP-MS), employing microwave acid digestion as a sample preparation method. The most abundant isotopes, 75As+, 65Cu+, 52Cr+, 58Ni+, 208Pb+, and 51V+, were determined in acyclovir ointment and its constituents. Elemental impurities in the pha
J. Braz. Chem. Soc.. Publicado em: 2017-01
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17. Selective Synthesis of (Z)-Chalcogenoenynes and (Z,Z)-1,4-bis-Chalcogenbuta-1,3-dienes Using PEG-400
We present here our results on the temperature controlled, selective hydrochalcogenation of 1,4-diorganyl-1,3-butadiynes with nucleophilic species of selenium, tellurium and sulfur generated in situ from the respective diaryl dichalcogenide and NaBH4. Using polyethylene glycol (PEG)-400 at 30 ºC the (Z)-chalcogenoenynes are obtained and at 90 ºC the (Z,Z)-
J. Braz. Chem. Soc.. Publicado em: 2016-11
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18. Evaluating the "Tape Tea" Myth as Low Cost Abuse Drug through Mass Spectrometry
The role of the "tape tea" as a low cost abuse drug is evaluated, by searching for possible inorganic and organic compounds after its preparation. Two energy sources are evaluated (conventional and microwave heating) for preparing the "tape tea" using new or used cassette (K7) or video home system (VHS) tapes. After optimizing all the inductively coupled pla
J. Braz. Chem. Soc.. Publicado em: 2016-10
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19. Microwave-assisted Synthesis of a ZrC-SiC Nanocomposite by Carbothermal Reduction and its Effect on Mean Particle Size
ZrC-SiC nanopowders were prepared by carbothermal reduction of ZrO2 and SiO2 with carbon black in argon gas atmosphere, using microwave energy as an alternative heating source. The samples were characterized by XRD, SEM and BET surface area analysis. The results indicate that highly crystalline ZrC-SiC composites with a mean particle size of about 80 nm can
Mat. Res.. Publicado em: 04/08/2016
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20. Derivatives of Cardanol through the Ene Reaction with Diethyl Azodicarboxylate
Cardanol is an alkyl/alkenyl phenolic material obtained from cashew nut shell liquid (CNSL), which is a byproduct of cashew nut processing. In an effort to develop new uses, cardanol was derivatized for the first time with diethyl azodicarboxylate (DEAD) through the ene reaction. The reaction was facile and required only the application of heat without a cat
J. Braz. Chem. Soc.. Publicado em: 2016-06
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21. Pressurized Flow Solubilization System Using Electromagnetic Induction Heating Technique for Simultaneous Determination of Inorganic Elements (Ba, Ca, Cd, Cu, Fe, Mg, Mn, Na, Pb, Sr, Zn) in Sonicate Slurries of Biological Materials by Microwave Induced Plasma Optical Emission Spectrometry (MIP-OES)
A pressurized continuous flow system using electromagnetic induction heating technique has been developed for the determination of trace and minor element content in biological samples by microwave induced plasma-optical emission spectrometry (MIP-OES). The system allows the continuous solubilization of samples at an optimized temperature of 120 °C and pres
J. Braz. Chem. Soc.. Publicado em: 2016-03
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22. Synthesis of 3-(1H-1,2,3-Triazol-1-yl)-2-(arylselanyl)pyridines by Copper-Catalyzed 1,3-Dipolar Cycloaddition of 2-(Arylselanyl)-3-azido-pyridines with Terminal Alkynes
We present here our results in the synthesis of eleven new 3-(1H-1,2,3-triazol-1-yl)-2-(arylselanyl)pyridines by copper-catalyzed azide-alkyne cycloaddition reactions. The reactions were performed in the presence of catalytic amount of copper(II) acetate and sodium ascorbate using a mixture of tetrahydrofuran/water (1:1) as solvent at room temperature in air
J. Braz. Chem. Soc.. Publicado em: 2015-11
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23. Microwave-Assisted Synthesis of β-1,2,3-Triazolyl-α-amino Esters
The reaction of ethyl (
p -methoxyphenylimino)acetate with propargyl bromide mediated by activated zinc powder afforded alkynyl amine, which was then reacted with a variety of organic azides using a microwave energy source, leading to β-1,2,3-triazolyl-α-amino esters in good yield.J. Braz. Chem. Soc.. Publicado em: 2015-07
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24. Facile Graphene Oxide Preparation by Microwave-Assisted Acid Method
Few-layered graphene oxide (GO) was prepared using a fast and energy-saving method by microwave-assisted acid technique. The oxygenated groups existing on the GO surface were determined using UV-Vis, X-ray photoelectron and Fourier-transform infrared spectroscopies. An oxygenated group percentage of 30% in mass for the GO was observed by thermogravimetric an
J. Braz. Chem. Soc.. Publicado em: 2015-05