4/2013
Exhaust emissions from cold starts of passenger cars and light trucks
When driving vehicles with a cold engine, a large amount of exhaust pollution is released into the environment, which affects the total emission balance. The measurement of emissions from cold starts is experi-mentally quite expensive and time consuming, so look for a reliable and robust predictive mathematical model that would simplify the calculation of emissions. It was measured and validated core set of emission data (CO, CH, NOx) characterizing a cold start passenger cars a light trucks and designed a simple algorithm for predic-tion of cold start emissions.
Experimental measurement of exhaust emissions of trucks in the simulation at the road junctions traf
For the calculation of emissions from the junctions it exist an absolute lack of research works, from which it would be possible to draw the necessary data. This fact applies especially trucks, for which measurement of emission data is experimentally and financially quite a challenging task. It was designed and experimentally verified unique process to perform engine and emission tests for heavy duty vehicles through which we can obtain a very valuable and quite unique set of infor-mation on emission characteristics of the representatives of the fleet of trucks in the Czech Republic during specific driving modes in the area of the junction.
Testing of electric properties of ceramic components for thermally stressed parts of high-temperatur
Heating elements are one of the important components of High Temperature Helium Loop. By means of heating elements the heating of test section of the loop to required temperature is provided even in high gas flow rates in the loop. The insulation of heating elements was manufactured of cordierite ceramics. With these elements the maximum projected temperature 900 °C could not be reached because of decreasing of electric resistance among the spirals. Therefore several tests were done in order to discover the reason of the problem. Consequently properties of new ceramic material based on corundum for manufacturing of the new heating elements were verified.
Biogas upgrading to biomethane
Biogas produced by methane fermentation of organic matter can be considered as a mixture of methane and carbon dioxide and it contains also other minor compounds, such as water vapor, sulfur in the form of hydrogen sulfide, ammonia, siloxanes, oxygen and halogen compounds. These substances may have negative effect on the upgrading process of biogas to biomethane. The adsorption is the one of the most widely used method for the removal of undesirable substances. This article is focused mainly on the removal of carbon dioxide from biogas, where its concentration is varyingfrom 25 up to 45 % vol. Separation of carbon dioxide was measured under laboratory conditions using model gas mixture containing 35 % vol. CO2 and 65 % vol. CH4. Consequently, the adsorption capacities for CO2 at selected adsorbents were measured using real biogas produced on the Waste Water treatment plant in Prague Bubeneč.
Testing of structural materials for high temperature gas cooled reactors
High temperature gas cooled reactors belong to a group called Generation IV Nuclear Reactors. Research organizations and industrial companies from the Czech Republic participate in research projects aimed at these reactors. The degradation of high temperature steels in impure helium at 750°C was tested. The changes of mechanical properties and composition and thickness of corrosion layers were tested after their exposure.