[en] This paper investigate the thermal behavior of integrated inductors, based on infrared thermography. The infrared imager used is a Ti35 IR Flexcam infrared camera. The samples were integrated inductors fabricated in AMIS 0.5μm, CMOS, TM1P twin-tub technology. The width of the inductor line was 12μm, the space 2μm, the metal thickness 1,02μm and the dimensions of the spiral were about 160μm x 160μm. The measurements were performed for various values of the dc current through the inductor. The use of the described method of thermal evaluation can lead to information concerning the functionality of the circuit under test. For example, it is feasible to estimate the position of the inductor in the chip, overheating - high amperage, no heat source - open circuitry, etc. However, it must be pointed out that the accuracy of the measurement results is limited by the camera's low noise equivalent temperature differences and its spatial resolution. (author)

[en] Mobile electronics are getting smaller and more crowded with high heat flux components. To cool electronic devices, engineers must confront two key facts: first, the miniature size of these units does not allow active cooling solutions, and second, their outside temperature must not exceed the user's comfort level. In the present paper, melting of PCM in a rectangular enclosure is studied for cooling electronic applications. Thermal and dynamic behaviours of the proposed cooling system and the effects of the aspect ratio on the dimensionless maximum temperature were analyzed. Temperature profile in substrate is studied and correlations for the maximum working time and the corresponding melt fraction were derived. (author)

[en] In the recent years more and more times and in more and more areas (fields) can we hear about thermography applications. These are mostly building-energetical, electrical and mechanical condition monitoring and human-biological applications. Thousands of termocameras are used in Hungary, but the knowledge of the operators and the analyzers is neither controlled nor qualified by any professional organization. In Hungary there is no THERMOGRAPH profession or recognized and claimed exam, this way the market is uncontrolled. This study mentioned the theoretical basics, the practical point of view, the current situation in Hungary and the foreign situation. (S.I.)

[en] In the design and operation of energy intensive systems, the possibility of improving the system's efficiency is very important to explore. The main way of improving efficiency is through thermodynamic analysis and optimization. Methods are universal and make it possible to estimate the fluxes and balances of all energy flows for every element of the system using a common criterion of efficiency. The thermoeconomical approach allows to retain all advantages of exergy method and simultaneously estimate the investment and other monetary costs of a system. In this paper is developed the method of thermoeconomical optimization of a heating system for cottage complex. Example of real optimization is given. (author)

[en] The advantages and disadvantages of hydrogen use by industrial combustion are critically presented. Greenhouse effect due natural water vapors from atmosphere and these produced by hydrogen industrial combustion is critically analyzed, together with problems of gas fuels containing hydrogen as the relative largest component. A comparison method between methane and hydrogen combustion for pressure loss in burner feeding pipe, is conceived. It is deduced the ratio of radiation useful heat transfer characteristics and convection heat transfer coefficients from combustion gases at industrial furnaces and heat recuperators for hydrogen and methane combustion, establishing specific comparison methods. Using criterial equations special processed for convection heat transfer determination, a calculation generalizing formula is established. The proposed comparison methods are general valid for different gaseous fuels. (author)

[en] Nowadays, the matter around the world, which is known by a very wide circle and gathers attention from the point of view of environmental issues, is the increase of global warming occurring because of the green house effect that has reached to dangerous level. In this study, pure vegetable oil, biodiesel, ethanol and methanol fuels have been considered as fuels having oxygen and in the first phase their fuel characteristics have been compared. The factors mentioned in the tables are determined as followings; HC emission, CO emission, NO_x emission, CO₂ emission, smoke emission, environment, engine power, fuel consumption, storage, transportation-safety, vehicle-engine modification, fuel price, institution-facility, reserve potential, engine wear, convenience for usage. (author)

[en] 384 x 288 (1/4 VGA) and 160 x 120 IRFPAs with 25 μm pixel pitch in TEC-less ceramics package, offer numerous advantages in the design of uncooled IR imaging systems. A read out integrated circuit structure with high level functions like serial link and 13 bits ADC make its use easier. Thin ceramic packages have been developed enabling one the possibility to build compact hand-held or helmet-mounted cameras. The TEC-less mode operability is completely demonstrated on a wide ambient temperature range. This feature opens the way to reduced power consumption systems needed for man-portable applications. (author)

[en] The research program was stipulated by reduction the service life of the tube recuperators of reheating furnaces at DUNAFERR metallurgical works in Dunaujvaros (Hungary) while replacement the natural gas by coke - oven gas as a furnace fuel took place and air preheating temperature was increased. The tests procedure consists in comparison of temperature and pressure distributions by air flows preheating under air moving inside the tube loops. Advantages of new recuperator design compared to ordinary one have been proven by validation of concept for adequacy to the testing results. The first tests have demonstrated enhancement of local specific and total heat fluxes transferred from flue gases to air flow within the MD tube loops in comparison with those for BD loops by 25 to 45% - dependence on temperature level within the heating (furnace) chamber and on preheated air flow rate. (author)

[en] The paper describes a new method which increases radiation heat transfer of furnace refractory and partly increases the gas tightness and life span of the lining. As heating-up time is decreased, the method also makes the operation of the furnace more flexible. Application of silicon carbide furnace coating increases the emissivity of ceramic fibre insulation by 45%, while that of shamotte by 20%. The phenomenon is illustrated by infrared thermograms and their temperature analysis. IR-emissivity was measured by infrared thermograms. Industrial applications are also referred to. (author)

[en] Experimental data of excess specific heat capacity provide important information for design of industrial process and for development of molecular models describing the thermodynamic behavior of the temperature. Fort he calculation of heat and mass exchange and the development of a mathematical model of the processes taking place in different reactors and technological processes, we need data on the thermophysical properties of carbon, chrom alloys in a wide range of temperature. An experimental device for measuring the heat capacity of the alloys in the temperature range 293-900 K by the method of monotonic heating was designed and constructed. The device consists of the measuring cell, a recorder, a Dewar vessel with melting ice, a pressure vessel. On this experimental device was measured for the first time the specific heat capacity of carbon and chrom in the temperature range (293-900 K). The common relative errors of measurement in specific heat capacity under a coefficient of confidence, α, of 0,95 are respectively 3,0%. (author)