High-temperature spectral thermometry in conditions of intense microwave electromagnetic fields

2020 ◽  
pp. 54-59
Author(s):  
B. A. Lapshinov ◽  
A. V. Mamontov
Keyword(s):  
Electromagnetic Field ◽  
High Temperature ◽  
Microwave Field ◽  
Negative Influence ◽  
Practical Application ◽  
Fiber Optic Cable ◽  
Heating Chamber ◽  
Close Proximity ◽  
Optical Fiber Cable ◽  
Spectral Pyrometry

In this paper, a practical application variant of the high-temperature spectral thermometry method for controlling the temperature of a dielectric object heated in a high-intensity microwave electromagnetic field is proposed. The advantages of using the spectral pyrometry method over the methods of color and brightness pyrometry when registering high temperatures (from 500 °C and above) are described. The optical fiber cable used in this method, which receives thermal radiation from an object heated in the microwave field, is subject to the negative influence of the electromagnetic field, which leads to its unacceptable heating and failure. To eliminate this phenomenon, a non-standard use of an cutoff waveguide placed not outside, but inside the microwave heating chamber is proposed. It is shown that this solution completely eliminates the negative influence of the electromagnetic field on the fiber optic cable and allows placing the receiving end of the cable in close proximity to the object being heated. The calculation of geometric parameters of the cutoff waveguide for the operating frequency of the electromagnetic field of 2450 MHz is given.

Microwave Field Distribution Uniformity Coefficient in the Grain Mass

2020 ◽  
Vol 67 (2) ◽  
pp. 87-92
Author(s):  
Dmitriy A. Budnikov
Keyword(s):  
Electromagnetic Field ◽  
Numerical Experiment ◽  
Microwave Field ◽  
Research Purpose ◽  
Coefficient Of Determination ◽  
Material Research ◽  
Dense Layer ◽  
Uniformity Coefficient ◽  
Average Value ◽  
Processed Material

The article considers the microwave electromagnetic fields as one of the options for improving the thermal drying of grain. Their application is limited by the high unevenness of the field propagation in the layer of the processed material. (Research purpose) The research purpose is in justifying the uniformity of distribution of microwave field in the layer of the processed grain. (Materials and methods) The article presents the scheme of computer models of microwave processing zones and waveguides, properties of materials for conducting a numerical experiment. (Results and discussion) A numerical experiment was performed to determine the uniformity coefficient of propagation of the microwave field in a layer of grain material. The article presents the dependencies. (Conclusions) It was found that the results of modeling the distribution of the electromagnetic field in the zone of microwave convective influence of the installation containing two sources of microwave power for processing the grain layer indicate a high level of its unevenness in the volume of the product pipeline. To assess the uniformity of the distribution of the electromagnetic field in the working area of a laboratory installation, there used a coefficient that is the ratio of the average value of the intensity in the zone of microwave convective action to its average value of the wave strength passing through the output of the waveguide. The values of the uniformity coefficient in the considered implementation options are in the range of 0.1757-0.4946 for a dense layer of wheat. To ensure a sufficient level of uniformity of the electromagnetic wave distribution in the volume of the microwave convective zone, the uniformity coefficient must be higher than 0.37. The article presents the dependence of the uniformity coefficient of the electromagnetic field on the humidity of the processed material by a third-degree polynomial with a coefficient of determination higher than 0.98.

scholarly journals CASIMIR ENERGY OF A DILUTE DIELECTRIC BALL AT ZERO AND FINITE TEMPERATURE

2002 ◽  
Vol 17 (06n07) ◽  
pp. 790-793 ◽  
Author(s):  
V. V. NESTERENKO ◽  
G. LAMBIASE ◽  
G. SCARPETTA
Keyword(s):  
Free Energy ◽  
Electromagnetic Field ◽  
Angular Momentum ◽  
High Temperature ◽  
Finite Temperature ◽  
Bessel Functions ◽  
Thermodynamic Characteristics ◽  
Casimir Energy ◽  
Addition Theorem ◽  
Temperature Expansion

The basic results in calculations of the thermodynamic functions of electromagnetic field in the background of a dilute dielectric ball at zero and finite temperature are presented. Summation over the angular momentum values is accomplished in a closed form by making use of the addition theorem for the relevant Bessel functions. The behavior of the thermodynamic characteristics in the low and high temperature limits is investigated. The T3-term in the low temperature expansion of the free energy is recovered (this term has been lost in our previous calculations).

scholarly journals Performance of Warm-Mixed Flame Retardant Modified Asphalt Binder

2019 ◽  
Vol 9 (7) ◽  
pp. 1491
Author(s):  
Ruixia Li ◽  
Kaiwei Zhang ◽  
Jiahui Wu ◽  
Wenjuan Liu
Keyword(s):  
High Temperature ◽  
Flame Retardant ◽  
Performance Test ◽  
Asphalt Binder ◽  
Negative Influence ◽  
Viscosity Reduction ◽  
Asphalt Binders ◽  
Index Test ◽  
Flame Resistance ◽  
Limiting Oxygen Index

In order to analyze the effect of flame retardant and warm mix asphalt (WMA) additives-Sasobit on the flame-retardant performance and pavement performance of asphalt binder, the limiting oxygen index test, conventional performance test, and Superpave evaluation index tests were performed on asphalt binders in the study. The test results show that flame retardant can effectively improve the flame resistance of asphalt binder, while Sasobit has a certain combustion-supporting effect. Therefore, when warm-mixed flame-retardant technology is applied, the concentration of Sasobit should be controlled appropriately. These two modifiers can significantly enhance the high-temperature performance of asphalt binder, but both of them have a slight negative influence on the low-temperature cracking resistance. Sasobit can substantially reduce the high-temperature viscosity of asphalt binder, which helps to improve the construction workability of asphalt binder, while the flame retardant adversely affects the viscosity reduction effect of Sasobit to a certain extent, but the overall impact is not large.

Microwave Equipment Considerations for High Temperature Studies in Ceramics

1988 ◽  
Vol 124 ◽  
Author(s):  
Martin Yonnone
Keyword(s):  
High Temperature ◽  
Microwave Heating ◽  
Microwave Field ◽  
Rapid Heating ◽  
Ceramic Materials ◽  
Microwave Energy ◽  
Ceramic Samples ◽  
Scientists And Engineers

The utilization of microwave energy as a source for the heating of ceramic materials is not a recent discovery. Notably, Von Hippel(1) and others including Tinga(2) investigated the microwave heating of ceramic materials in the 50's and 60's. Today, many microwave scientists and engineers are working on the complexities associated with the rapid heating exhibited by ceramic samples in the microwave field.

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