"A Pocket Sized Monitor of Dangerous Microwave Power Levels"
A miniature battery-operated microwave power monitor is described which operates across the threshold range of biologically dangerous power levels with approximately frequency-independent characteristics up to about 100GHz. CMOS circuitry causes an alarm signal to occur, or enables one to integrate the total microwave energy received over a given period on the basis of a thermal change of resistance in a thin Ge film due to microwave absorption.
Infrared Absorption of Thin Metal Films
The maximum infrared absorption that can be obtained in an unsupported metal film in air is 50 percent. It is shown that the absorption may be increased by supporting the metal on a dielectric of high refractive index, provided that the radiation passes through the dielectric to the metal. Under certain conditions there is then no reflection from the layer. If the combination is reversed so that the radiation is incident on the metal first, a low absorption results. If the supporting dielectric is of low refractive index neither direction will lead to high absorption; in this case the use of another system, with metal on each side of the support is preferable. Using whichever of the two systems is appropriate to the supporting dielectric, an absorption of 70 percent is always obtainable.
Quantitative and qualitative relationship between swirl burner operatingconditions and pulverized coal flame length
Abstract Currently, there are used in power plants two types of burners to combustion the pulverized coal: jet burners and swirl burners. Most of the published works in the field of analysis of burners operating conditions are related to jet burners and are limited to initial region of the flame at the outlet of the burner. For jet burners an offset between the burner outlet and the flame beginning point could be analyzed. In the case of swirl burners with the pre-mixing diffuser chamber an offset between flame ignition point and burner outlet is usually not visible. Because already in the pre-mixing diffuser chamber of swirl burner occurs the ignition of coal-dust together with oxidant-gas cloud and thereby the formation of the flame. Therefore, the analysis of operating conditions for this types of burners requires a different approach. There is a lack of researches, in which will be analyzed changes of the flame length, that are caused by changes of design and operating parameters of swirl burner with the pre-mixing diffuser chamber. Therefore the aim of this study was to implement and verify the methodology for estimating the flame length, which will allow monitoring changes of operating conditions, that are caused by changes of design and operating parameters of swirl burner with the pre-mixing diffuser chamber. To carry out the analysis of the image of the coal flame, the two algorithms have been presented. This two algorithms, being based on the video images of the coal flame allows to specify and detect the end point of the flame and on that basis the length of the flame, as well as the fluctuation changes of flame length can be later determined. Both, the change thermal loads of coal burner, streams of secondary air, as well as the constructional change of the angle of swirler assemblies, resulted in distinct changes in the length of the pulverized coal flame.