We have investigated the concept of an integrated system for small, manportable power units. The focus of this study is the direct thermal coupling of a methanol steam reformer (MSR) and a high-temperature proton exchange membrane fuel cell (HT PEMFC) stack. A recently developed low-temperature (LT) MSR catalyst (CuZnGaOx) was synthesized and tested in a designed reforming reactor. The experimental data show that at 200 °C the complete conversion of methanol is achievable with a hydrogen yield of 45 cm3 min-1 gCAT -1 . An experimental setup for measuring the characteristics of the integrated system was designed and used to measure the characteristics of the twocell HT PEMFC stack. The obtained kinetic parameters and the HT PEMFC stack characteristics were used in the modeling of the integrated system. The simulations confirmed that the integrated LT MSR/ HT PEMFC stack system, which also includes a vaporizer, can achieve a thermally selfsustained working point. The base-case scenario, established on experimental data, predicts a power output of 8.5 W, a methanol conversion of 98.5%, and a gross electrical efficiency (based on the HHV) of the system equal to 21.7%. However, by implementing certain measures, the power output and the electrical efficiency can readily be raised to 11.1 W and 35.5%, respectively.
COBISS.SI-ID: 15546139
A pure tire pyrolysis oil produced from waste tires was utilized in a modern 4-cylinder, turbocharged and intercooled, automotive Diesel engine. Due to its low cetane number, cetane improvers, external energy addition or increased compression ratios are generally required for its use in Diesel engines. Successful utilization of pure tire pyrolysis oil is also achievable with the addition of pilot injection but limited to mid- to high-load operating range. The first objective of the present study is therefore focused on further extension of the operating range towards lower loads by novel combined application of the exhaust gas recirculation and tailored main injection strategy. As the second objective, the article provides for the first time an in-depth analysis of the particulate emissions of the tire pyrolysis oil measured with two different methods. In this area it identifies and reasons challenges related to determination of the particulate emissions for alternative fuels. The original contribution of the presented approach thus arises from the holistic assessment of interactions between the exhaust gas recirculation ratios, injection parameters and combustion as well as gaseous and particulate emissions formation phenomena.
COBISS.SI-ID: 15296027
Traffic noise emission and its propagation can be effectively measured and modelled. Results of traffic noise modelling are very close to the results of measurement, typically within %3 dB range in case of noise propagation around elementary situations. In a real complex environment, the deviation of results is larger. The procedure of gathering the information about the traffic attributes and the elements composing the propagation path is essential for traffic noise modelling, however it differs from laboratory to laboratory. The deviation of input data and consequently the deviation of modelling results occur, if different sources of information are used. Fourteen inspection bodies participated in the inter-laboratory comparison, which was organized in order to compare procedures of different laboratories with a purpose to identify key parameters influencing the deviation of noise modelling results. Presented inter-laboratory comparison (ILC) of traffic noise modelling is particularly reliable because it includes both, the comparison of modelling results and the comparison of measurement results. Assessment of noise level relative to the absolute reference value was not the primarily objective of the ILC, the main goal was the analysis of the risk of systematic errors. Conclusions of the study indicate that traffic noise models and noise propagation models can be regarded as an extrapolation of measurement results from one location to a wider surrounding area.
COBISS.SI-ID: 15775259
Within the last years there has been a substantial increase in reports of utilization of hydrodynamic cavitation in various applications. It has came to our attention that many times the results are poorly repeatable with the main reason being that the researchers put significant emphasis on the value of the cavitation number when describing the conditions at which their device operates. In the present paper we firstly point to the fact that the cavitation number cannot be used as a single parameter that gives the cavitation condition and that large inconsistencies in the reports exist. Then we show experiments where the influences of the geometry, the flow velocity, the medium temperature and quality on the size, dynamics and aggressiveness of cavitation were assessed. Finally we show that there are significant inconsistencies in the definition of the cavitation number itself. In conclusions we propose a number of parameters, which should accompany any report on the utilization of hydrodynamic cavitation, to make it repeatable and to enable faster progress of science and technology development. The paper was cited 22 times within one year of publication.
COBISS.SI-ID: 14676763
The aim of this study was to accurately quantify the impact of hydrodynamic cavitation on the infectivity of bacteriophage MS2, a norovirus surrogate, and to develop a small scale reactor for testing the effect of hydrodynamic cavitation on human enteric viruses, which cannot be easily prepared in large quantities. For this purpose, 3 mL scale and 1 L scale reactors were constructed and tested. Both devices were efficient in generating hydrodynamic cavitation and in reducing the infectivity of MS2 virus. Furthermore, they reached more than 4 logs reductions of viral infectivity, thus confirming the scalability of hydrodynamic cavitation for this particular application. As for the mechanism of page inactivation, we suspect that cavitation generated OH% radicals formed an advanced oxidation process, which could have damaged the host's recognition receptors located on the surface of the bacteriophage. Additional damage could arise from the high shear forces inside the cavity. Moreover, the effectiveness of the cavitation was higher for suspensions containing low initial viral titers that are in similar concentration to the ones found in real water samples. According to this, cavitation generators could prove to be a useful tool for treating virus-contaminated wastewaters in the future. The article was accompanied by reviewers and the editor of Water Research (IF 7.7) with comments like: historical milestone, extremely high potential effect, potentially game-changing technology for virus inactivation.
COBISS.SI-ID: 15600923