نتایج جستجو برای: microwave heating
تعداد نتایج: 103154 فیلتر نتایج به سال:
پلی کربنات یکی از پلاستیکهای مهمی است که به صورت گسترده در تولید لوحهای فشرده، قطعات رایانه، مواد ساختمانی و غیره مورد استفاده قرار می گیرد. این پلیمر بصورت عمده از تراکم مونومر بیس فنولa (bpa) و کربنیل کلرید یا دی متیل کربنات ها بدست می آید. در سالهای اخیر بازیافت شیمیایی پلی کربنات بیشتر مورد توجه بوده است. بازیافت شیمیایی پلی کربنات برای بدست آوردن مواد اولیه آن با روشهای متفاوتی مانند تجزی...
In this work, the investigation of wave absorption, phase formation, crystal structure and magnetic properties of SrFe12O19 hexa-ferrites nanoparticles that synthesized by co-precipitation using a microwave heating system and polyaniline-SrFe12O19 was carried out by using a combination of vector network analyser (VNA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier tra...
Microwave heating has been shown to influence various inorganic chemical reactions. Substantial reductions in the synthesis time for materials have been reported (1). Additionally, product characteristics and quality of materials synthesized by microwave heating are different from those synthesized under conventional heating methods. The mechanism which results in microwave enhancement is not c...
Until recently traditional heating in organic chemistry has been done with oil heating baths or using electric heat exchangers. With the advent of microwave equipment, heating by microwaves was rapidly introduced as standard method in organic chemistry laboratories, mainly because of the convenient possibility to operate at high temperature accompanied by accelerated reaction rates. In the pres...
Pine sawdust pyrolysis was carried out respectively using microwave and conventional electrical heating at different temperatures in order to understand the properties of pyrolytic products from microwave pyrolysis of biomass. Less char material was obtained by microwave pyrolysis compared to conventional heating at the same temperature. While comparing the components of the pyrolytic gases, it...
Microwave radiation, an electromagnetic radiation, is widely use as a source of heating in organic synthesis. The basic mechanisms observed in microwave assisted synthesis are dipolar polarization and conduction. Microwave assisted organic synthesis (MAOS) has emerged as a new “lead” in organic synthesis. The technique offers simple, clean, fast, efficient, and economic for the synthesis of a l...
The complexity and challenges in noncontact temperature measurements inside microwave-heated catalytic reactors are presented in this paper. A custom-designed microwave cavity has been used to focus the microwave field on the catalyst and enable monitoring of the temperature field in 2D. A methodology to study the temperature distribution in the catalytic bed by using a thermal camera in combin...
A calcium sennoside was extracted by developed microwave assisted extraction technique from Senna leaves. Microwave extraction was carried out at 250 W for 20 minutes, 350 W for 15 minutes and 450 W for 10 min heating period, these produced increase yields of calcium sennosides when compared to conventional heating. The yield of calcium sennosides obtained by microwave extraction was found to b...
A hybrid calorimeter is described whereby the test specimen may be heated using either hot air and/or microwave radiation. Thus it is possible to study phase transitions of materials under conditions ranging from purely conventional heating to pure microwave heating or mixtures thereof. Measurements using silver iodide showed that its phase change from the low temperature β-phase to the high te...
Microwave energy has been in use for variety of applications for over 50 years. These applications include communication, food processing, wood drying, rubber vulcanization, medical therapy, polymers, etc. In the last two decades microwave heating has been also applied very effectively and efficiently to heat and sinter ceramic materials. Microwave heating is recognized for its various advantag...
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