Измерение температуры листовых материалов в микроволновых установках типа бегущей волны
Theoretical and experimental research results in the field of high-performance microwave technologies of sheet materialsare presented. Sections of two-dimensional periodic slow-wave systems are used as heating elements. Divergence of theoretical and experimental temperature distribution characteristics in the sheet material does not exceed 3%, and the temperature deviation in the material from the nominal temperature value does not exceed 5%.
The experimental research results of the basalt cardboard thermal treatment with the microwave electromagnetic energy application are presented in the article. The weight change diagrams of the basalt cardboard samples during the drying process are given. Changes in the temperature behaviour are analyzed on the surface and inside the samples depending on coupling medium. An advice on the drying process parameters improvement is given.
The results of calculation and measurement of temperature distribution in the leasing out of dielectric materials which are heated up in the microwave devices wave-water type. The calculation method of microwave devices of a waveguide type of heat treatment of sheet dielectric materials. Considered microwave devices, Otley-exclusive feature of which is the change of the geometrical sizes of a narrow wall of a rectangular waveguide, working mainly on the type of waves to ensure a uniform temperature in the processed sheet the dielectric-dielectric material.
Tthe IMPI 48 program offers topics for everyone interested in learning about the latest developments in microwave power science and technology. Each year, IMPI brings together researchers, technologists and engineers from across the globe to share the latest findings of microwave and radio frequency power systems for non-communication applications, including food technology, chemical and material processing, and new emerging technologies. IMPI 48 Symposium was held at the Doubletree Hotel on Canal Street in downtown New Orleans, Louisiana, USA. New this year, IMPI 48’s Food Science and Technology Program will cover topics such as: microwavable food safety, microbiological testing, product validation, microwave oven standards, microwave leakage monitoring, industrial microwave and RF food processing.
Theoretical and experimental research results in the field of highperformance microwave technologies of sheet materials' with small dielectric losses thermal treatment are presented. To increase the electric field decay constant amplitude in the material with small dielectric losses sections of twodimensional periodic slowwave systems are used as heating elements. The microwave construction is based on a module, which consists of two identical in design and parameters microwave heating sections, positioned one above the other, and the electromagnetic field energy propagates along these sections in opposite directions. Processed material is positioned between two sections. Each heating section consists of the twodimensional periodic slowwave system, which on the one hand conditions with the microwave energy source, and on the other hand conditions with the water load, in which there is a sensor of passing power for the control of technological process. The long line with given boundary conditions was used as a model of microwave devices with the processed material. Special design of filters that impede microwave radiation from a working setup were used to reduce the level of a side radiation at the input and output of the processed material. Divergence of theoretical and experimental temperature distribution characteristics in the sheet material (ebonite) with small dielectric losses does not exceed 4%, and the temperature deviation in the material from the nominal temperature value does not exceed 7%. To materials with low dielectric losses in particular, relate: polystyrene, polypropylene and polyethylene with different fillings, for example, in the form of 10% carbon black or other dyes, plexiglass, ebonite and other plastics. Heat treatment of such materials by gas or by other known methods does not lead to the whole volume uniformity of heating due to the low plastics' heat conductivity and in subsequent operations, such as pressing or stamping, cracking or other unwanted defects arise.
Wide application of radiofrequency (RF) and microwave (MW) heating of dielectric materials is restrained by the relatively small specific RF losses and inhomogeneity of the MW energy penetration in the treated objects. These disadvantages may be overcome by using applicators based on slow-wave structures which support modes in which the phase velocity is less than the free-space velocity of light These structures concentrate the electromagnetic field relatively homogeneously along the system axis. Diverse applications have been found including food heating, disinfecting agricultural products, and electro-coagulation.
The computational model of the temperature sensors integrated on the IC chip with power transistors is developed. The 2D/3D problem of sensor placement is mathematically described by the classic heat transfer equation coupled with the equation for current density distribution. It is shown that parasitic effects of sensor current displacement and thermo-emf generation resulting from a temperature gradients (Seebeck effect) must be taken into account. For this purpose the special differential equation is introduced. The examples of point- and strip-like temperature sensors modeling for power BJTs and ICs are demonstrated.
Questions of the even temperature distribution creation in the volumetric materials with different dielectric losses placed in the beam-type microwave device are examined. The volumetric material was irradiated by two types of antennas which provided perpendicular and parallel flux direction of the electric-field vector relatively to the material's surface. Experimental data on the temperature field distribution in the volume of material is presented. It is shown that the total temperature dispersion is less than 5ºC inside the material heated up to 80ºC.
By using superconducting quantum interference device (SQUID) magnetometry, we investigated anisotropic high-field (H less than or similar to 7T) low-temperature (10 K) magnetization response of inhomogeneous nanoisland FeNi films grown by rf sputtering deposition on Sitall (TiO2) glass substrates. In the grown FeNi films, the FeNi layer nominal thickness varied from 0.6 to 2.5 nm, across the percolation transition at the d(c) similar or equal to 1.8 nm. We discovered that, beyond conventional spin-magnetism of Fe21Ni79 permalloy, the extracted out-of-plane magnetization response of the nanoisland FeNi films is not saturated in the range of investigated magnetic fields and exhibits paramagnetic-like behavior. We found that the anomalous out-of-plane magnetization response exhibits an escalating slope with increase in the nominal film thickness from 0.6 to 1.1 nm, however, it decreases with further increase in the film thickness, and then practically vanishes on approaching the FeNi film percolation threshold. At the same time, the in-plane response demonstrates saturation behavior above 1.5-2T, competing with anomalously large diamagnetic-like response, which becomes pronounced at high magnetic fields. It is possible that the supported-metal interaction leads to the creation of a thin charge-transfer (CT) layer and a Schottky barrier at the FeNi film/Sitall (TiO2) interface. Then, in the system with nanoscale circular domains, the observed anomalous paramagnetic-like magnetization response can be associated with a large orbital moment of the localized electrons. In addition, the inhomogeneous nanoisland FeNi films can possess spontaneous ordering of toroidal moments, which can be either of orbital or spin origin. The system with toroidal inhomogeneity can lead to anomalously strong diamagnetic-like response. The observed magnetization response is determined by the interplay between the paramagnetic-and diamagnetic-like contributions.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.