نتایج جستجو برای: microwave heating
تعداد نتایج: 103154 فیلتر نتایج به سال:
A two dimensional finite element model (FEM) was developed to Predict the temperature distribution in coal particles with the aid of microwave heating. However, transient temperature profile for coal particles of high dielectric loss factor is obtained when exposed to microwave radiation. The heat equation and Maxwell’s equation are simultaneously solved using the finite element method to predi...
We prepared trifluoroacetyl, pentafluoropropyl, and heptafluorobutyl derivatives of amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA) in 45 s, 1 min, and 6 min, respectively, by using microwave irradiation. Conventional techniques require heating the reaction mixture for 15 min at 40 degrees C for trifluoroacetyl derivatives, 15 min at 75 degrees C for pentafluoropropyl...
The oxidative coupling of methane was investigated over alumina supported La2O3/CeO2 catalysts under microwave dielectric heating conditions at different oxygen concentrations. It was observed that, at a given temperature using microwave heating, selectivities for both ethane and ethylene were notably higher when oxygen was absent than that in oxygen/methane mixtures. The differences were attri...
Dielectric properties and carbothermic reduction of zinc oxide and zinc ferrite by microwave heating
This paper aims to study the dielectric properties and carbothermic reduction of zinc oxide (zincite, ZnO) and zinc ferrite (franklinite, ZnFe2O4) by microwave heating. To achieve this aim, the dielectric properties were measured with an open-ended coaxial method to understand the behaviour of the samples under microwave irradiation. The effects of microwave power, duration time and sample mass...
The use of pasteurization units (PU) as a measure of the lethal effect of processes was proposed with the aim of comparing conventional and novel thermal technologies. Kiwifruit puree was subjected to microwave (1000 and 900 W) and conventional (97 C) heating. Processing conditions of the treatments were chosen to simulate a pasteurization treatment. The temperature profiles of the samples duri...
Microwave heating processes involve electromagnetic and thermal effects coupled together through the local temperature dependence of the material dielectric properties. This paper presents a one-dimensional model for the coupled electromagnetic-thermal process and demonstrates its solutions for typical problems. The local temperature dependence of the lossy dielectric medium is taken into accou...
Gout is a disease with elusive treatment options. Reduction of the size of l-alanine crystals as a model crystal for gouty tophi with the use of a monomode solid-state microwave was examined as a possible therapeutic aid. The effect of microwave heating on l-alanine crystals in the presence of gold nanoparticles (Au NPs) in solution and synovial fluid (SF) in a plastic pouch through a synthetic...
The influence of granulometric properties of the material and of the operational conditions on the drying kinetics of nonhygroscopic material was studied. Four fraction sizes of dolomite were chosen and dried in four dryers by different heating methods. Dolomite was dried in a microwave dryer under different microwave heating powers. During convective drying the effects of temperature and super...
Microwave thermography (MWT) has many advantages including strong penetrability, selective heating, volumetric heating, significant energy savings, uniform heating, and good thermal efficiency. MWT has received growing interest due to its potential to overcome some of the limitations of microwave nondestructive testing (NDT) and thermal NDT. Moreover, during the last few decades MWT has attract...
The purpose of this work was to explore the application of microwaves for the low temperature regeneration of activated carbons saturated with a pharmaceutical compound (promethazine). Contrary to expectations, microwave-assisted regeneration did not lead to better results than those obtained under conventional electric heating. At low temperatures the regeneration was incomplete either under m...
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