Power loss density of electromagnetic waves in unimolecular reactions

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

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Microwave Assisted Synthesis of Organic Compounds and Nanomaterials

10.5772/intechopen.98224 ◽

2021 ◽

Author(s):

Anjali Jha

Keyword(s):

Green Chemistry ◽

Organic Synthesis ◽

Electric Fields ◽

Chemical Reactions ◽

Dipole Moments ◽

Electric Heating ◽

Microwave Assisted Synthesis ◽

Microwave Chemistry ◽

Microwave Assisted ◽

Promising Area

In the Conventional laboratory or industry heating technique involve Bunsen burner, heating mental/hot plates and electric heating ovens. To produce a variety of useful compounds for betterment of mankind, the Microwave Chemistry was introduced in year 1955 and finds a place in one of the Green chemistry method. In Microwave chemistry is the science of applying microwave radiation to chemical reactions. Microwaves act as high frequency electric fields and will generally heat any material containing mobile electric charges, such as polar molecules in a solvent or conducting ions in a solid. Polar solvents are heated as their component molecules are forced to rotate with the field and lose energy in collisions i.e. the dipole moments of molecules are important in order to proceed with the chemical reactions in this method. It can be termed as microwave-assisted organic synthesis (MAOS), Microwave-Enhanced Chemistry (MEC) or Microwave-organic Reaction Enhancement synthesis (MORE). Microwave-Assisted Syntheses is a promising area of modern Green Chemistry could be adopted to save the earth.

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Microwave Heating Assisted Biorefinery of Biomass

Innovative Solutions in Fluid-Particle Systems and Renewable Energy Management ◽

10.4018/978-1-4666-8711-0.ch005 ◽

2015 ◽

pp. 131-166 ◽

Cited By ~ 2

Author(s):

Sherif Farag ◽

Jamal Chaouki

Keyword(s):

Temperature Gradient ◽

Electromagnetic Radiation ◽

Microwave Heating ◽

Chemical Reactions ◽

Electromagnetic Waves ◽

Thermochemical Treatment ◽

Scaling Up ◽

Conventional Heating ◽

Essential Information ◽

Pros And Cons

This chapter debates the potential of the biorefinery of biomass using microwave heating. First, the essential information regarding electromagnetic radiation is explained and the pros and cons of microwave heating versus conventional heating, especially in the thermochemical treatment of biomass, are discussed. Different methodologies for predicting and measuring the temperature gradient within a material subjected to electromagnetic waves are demonstrated. The chapter summarizes the key conclusions of various investigations regarding the effects of microwave heating on chemical reactions and presents how electromagnetic radiation can assist the biorefinery of biomass. Finally, the issues and limitations regarding scaling-up microwave heating are elucidated, along with possible solutions to these problems.

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Microwave-Assisted Chemical Reactions

Chemical Engineering & Technology ◽

10.1002/ceat.200301836 ◽

2003 ◽

Vol 26 (12) ◽

pp. 1207-1216 ◽

Cited By ~ 103

Author(s):

M. Nüchter ◽

U. Müller ◽

B. Ondruschka ◽

A. Tied ◽

W. Lautenschläger

Keyword(s):

Chemical Reactions ◽

Microwave Assisted

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Frequency dependence of microwave-assisted electron-transfer chemical reactions

Molecular Physics ◽

10.1080/00268976.2019.1685691 ◽

2019 ◽

Vol 118 (13) ◽

pp. e1685691

Author(s):

Guennadi A. Kouzaev

Keyword(s):

Electron Transfer ◽

Frequency Dependence ◽

Chemical Reactions ◽

Microwave Assisted

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Microwave‐assisted Chemical Reactions

Journal of Macromolecular Science Part A ◽

10.1080/10601320701285136 ◽

2007 ◽

Vol 44 (6) ◽

pp. 651-657 ◽

Cited By ~ 18

Author(s):

Ah Keow Man ◽

Radiman Shahidan

Keyword(s):

Chemical Reactions ◽

Microwave Assisted

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Pilot Plant for Continuous Flow Microwave-Assisted Chemical Reactions

Microwaves in Catalysis ◽

10.1002/9783527688111.ch7 ◽

2015 ◽

pp. 141-154

Author(s):

Mitsuhiro Matsuzawa ◽

Shigenori Togashi

Keyword(s):

Chemical Reactions ◽

Pilot Plant ◽

Continuous Flow ◽

Microwave Assisted

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Effect of Sand Base Grade and Density of Moulding Sands with Sodium Silicate on Effectiveness of Absorbing Microwaves

Archives of Foundry Engineering ◽

10.1515/afe-2016-0059 ◽

2016 ◽

Vol 16 (3) ◽

pp. 103-108

Author(s):

M. Stachowicz

Keyword(s):

Relative Density ◽

Sodium Silicate ◽

Microwave Power ◽

Power Loss ◽

Electromagnetic Waves ◽

Slot Line ◽

Absorbed Power ◽

High Silica ◽

Sand Base ◽

Reflected Power

Abstract In the paper, presented is a research on effectiveness of absorbing electromagnetic waves at frequency 2.45 GHz by unhardened moulding sands prepared of three kinds of high-silica base and a selected grade of sodium silicate. Measurements of power loss of microwave radiation (Pin) expressed by a total of absorbed power (Pabs), output power (Pout) and reflected power (Pref) were carried-out on a stand of semiautomatic microwave slot line. Values of microwave power loss in the rectangular waveguide filled with unhardened moulding sands served for determining effectiveness of microwave heating. Balance of microwave power loss is of technological and economical importance for manufacture of high-quality casting moulds and cores of various shapes and sizes. It was found that relative density influences parameters of power output and power reflected from samples of moulding sand placed in a waveguide. Absorption expressed by the parameter Pabs is not related to granularity of high-silica base: fine, medium and coarse. It was found that the semiautomatic microwave slot line supports evaluation of effectiveness of microwave absorption on the grounds of power loss measurements and enables statistic description of influence of relative density of the sandmix on penetration of electromagnetic waves in unhardened moulding sands.

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