Miloš Klíma

Plasma discharge at atmospheric pressure can be used to modify the surface electrical strength of insulators made of dielectric materials, thermosets and thermoplastics. The methodology of surface treatment by plasma discharge was published and applied to typical samples of materials with dimensions of 100 × 100 mm. To make the methodological procedure for influencing and predicting the desired change in the dielectric surface industrially applicable, it was necessary to develop a diagnostics methodology for applying plasma discharge at atmospheric pressure. This method was tested on previously selected and tested types of materials on samples of two types (thermoset, thermoplastic). The effects of measuring and evaluating the RF spectrum, along with the corresponding long-term change in the surface strength E_p of the dielectric sample, were demonstrated. This work presents repeated extension tests with statistical evaluation of the effects of surface treatment of dielectric samples using a slot plasma chamber in Ar, N₂ and O₂ atmospheres. The surface structure was modified using precursor-free plasma discharge according to the developed methodologies with the addition of radiometric evaluation of the plasma discharge. Changes in surface properties were measured and evaluated as a function of exposure time and the stability of the modification was evaluated with a prediction of the expected long-term surface properties.

The research focuses on the methodology of preparing a concept and application scenarios for alternative sources of energy in transportation. The ideas and interpretations are not strictly limited to automobile transport but also reach into other areas of using and processing energy. The conceptual approach to the choice of sources, with the aim of securing the efficient use of energy conversion, is illustrated on the model embodiment embedded in a passenger car; the relevant presentation is centered on an experiment focusing on the linear arrangement of a driven electromagnetic generator. This involves generating and collecting energy for not only the accumulation of electrical energy using relatively independent systems, but also for direct use within driving needs. In the modeled example, the supplied energy is assumed to be in a range of constant power from p = 10 W to 50 kW (200 kW). The given example of the design of the choice of energy conversion sources and the use of generators in a passenger car shows the possibilities, limitations, and variants for demonstrating the requirements relating to a simple driving mode. The application of a linear or cylindrical internal combustion engine is considered for a specific set mode of the car. Variants of suitable uses of the accumulated energy in compressed air are proposed. The use of light and thermal forms of energy is considered for additional forms. As an experimental example, the use of generators derived from vibration harvesters is shown. The proposed energy generation arrangement can be controlled and optimized for specific transport tasks. The generation and accumulation of energy can be employed in the form of electrical energy, as kinetic energy for direct use in driving, or to accumulate in compressed air for later use. Solar energy can be used directly or can be accumulated. The combustion unit can serve as a source of kinetic energy or also to store energy for further use. The concept of alternative sources is based on known methods of use in other industries. The model combination of resources and its simple analysis in the concept of resource selection is demonstrated on an example of an application in passenger cars.

Plasma discharges under atmospheric pressure can be used to modify the electrical properties of metallic and dielectric surfaces. The aim of such a modification is to achieve an improvement in the characteristic parameters of the surface, for example in the area of the electrical strength of the surface, in order to achieve a higher ultimate level of electrical breakdown E b when tested with pulsed or alternating electrical voltages. So far, research has focused on a set of functional experiments carried out using plasma on samples of two types of dielectric materials (thermoset, thermoplastic) with an impact on the final effect of the level of electrical breakdown voltage, electrical intensity and E b. surface conductivity. The treatment technology requires repeatability and consideration of the industrial deployment conditions of plasma technology. The surface structure was modified in a defined and repeatable way by plasma discharge under atmospheric pressure without the presence of precursors. Methods to evaluate these modifications assessed the change in parameters related to sample type, repeatability and prediction of treatment stability. Subsequently, the surface strength of both the modified samples and the samples not affected by the plasma discharge was measured.

The ability of atmospheric pressure plasma jets to treat complex non-planar surfaces is often cited as their advantage over other atmospheric plasmas. However, the effect of complex surfaces on plasma parameters and treatment efficiency has seldom been studied. Herein, we investigate the interaction of the atmospheric pressure plasma slit jet (PSJ) with block polypropylene samples of different thicknesses (5 and 30 mm) moving at two different speeds. Even though the distance between the slit outlet and the sample surface was kept constant, the treatment efficiency of PSJ ignited in the Ar and Ar/O2 gas feeds varied with the sample thickness due to the plasma parameters such as filament count and speed being affected by the different distances of the ground (the closer the ground is, the higher the discharge electric field). On the other hand, the Ar/N2 PSJ diffuse plasma plumes were less affected by the changes in the electric field, and the treatment efficiency was the same for both sample thicknesses. Additionally, we observed a difference in the efficiency and uniformity of the PSJ treatment of the edges and the central areas in some working conditions. The treatment efficiency near the edges depended on the duration of the filament contact, i.e., how long the local electric field trapped the filaments. Conversely, the treatment uniformity near the edges and in the central areas was different if the number of filaments changed rapidly as the discharge moved on and off the sample (the 5 mm samples treated by easily sustained Ar PSJ).

Plasma discharges under atmospheric pressure are applicable for modifying the electrical properties of dielectric surfaces. The aim of the plasma discharge treatment of such surfaces is to design a procedure so that its characteristic parameters improve the resulting levels of the breakdown electrical strength E_b when tested under pulsed or alternating electrical voltages. In this research, a set of functional experiments performed by using plasma in samples of two types of materials (thermoset, thermoplastic) were processed and evaluated, and the resulting effect of the magnitude of the breakdown electrical voltage, electrical intensity, and electrical conductivity of the surface were compared. A slit plasma chamber, previously described and parameterized, was employed to treat the surface of the dielectric samples. The surface structure was modified via plasma discharge without precursors, and methodologies were developed to evaluate these modifications with respect to the change in the electrical strength parameters of the insulator surface. Subsequently, the surface strength of the affected and unaffected samples was measured and evaluated as a function of exposure time, and the stability of the modification was assessed. The first methodical test showed that plasma discharge without precursors improved the long-term surface electrical strength of the dielectric surface. The test and its parameters were carried out with respect to feasibility in an industrial environment.

The cold atmospheric plasma jets change their character when interacting with the different surfaces. Since such interaction is the primary area of plasma jet applications, it is essential to monitor the process. The non-linearity of the RF plasma slit jet (PSJ) was analyzed using the VI probes and a novel method, the non-intrusive antenna measurements. Regardless of the experimental setup and gas mixture (Ar, Ar/O₂, Ar/N₂), the PSJ frequency spectrum consisted of the following main features: dominant fundamental frequency peak, relatively strong odd harmonics, and significantly weaker even harmonics. The lowest degree of non-linearity was recorded for the Ar PSJ ignited against a grounded target. Admixing a molecular gas increased the discharge non-linearity. It was attributed to the enhancement of secondary electron emission from the dielectric surfaces. In addition to the non-linearity analysis, the antenna spectra were for the first time used to determine the semi-quantitative values of the PSJ-radiated electric field. The electric fields decreased by a factor of 2 after the admixing of nitrogen and oxygen molecular gases. Out of the studied targets, the highest electric fields were observed when plasma impinged on the grounded targets, followed by the floating target (2× lower) and the PSJ ignited in the open space configuration (4× lower than in the grounded target configuration).

Herein, we discuss the modeling and verification of RF sensed signals in a simple plasma channel (plasma jet) at the generator frequency of f = 13.56 MHz, assuming plasma discharge at atmospheric pressure. The actual experiment was preceded by a basic numerical analysis and evaluation of several variants of the geometric/numerical model of a simple plasma channel formed in a glass capillary chamber; this step was performed with different electrode configurations. The analyses also included the impact of the location of the sensing element (i.e., the antenna) on the resulting evaluated electromagnetic signal. Furthermore, a numerical model with concentrated parameters facilitated a comparative analysis centered on the impact of plasma concentration and composition in the monitored electromagnetic RF spectrum of the channel. The theoretical outputs were verified via experiments and compared. This methodology finds use in the radio-frequency evaluation of plasma parameters in both simple capillary nozzles and more complex, slit-designed plasma chambers.

The image/video quality is a key issue in security video systems. Therefore the objective image/video quality criteria are extensively studied. In this paper, the novel full reference objective metric for image quality assessment is proposed. This metric is based on FSIM. The ROI detection is embedded in order to improve the performance. For ROI estimation, the ground truth data together with two different algorithms were used and compared - The security and multimedia images from LIVE database were used for performance evaluation. The correlation between the objective and subjective tests of multimedia images was calculated using Pearson's and Spearman Rank Order Correlation Coefficient. For performance comparison the state-of-the-art full reference objective image quality metrics were used; PSNR, SSIM, MS-SSIM, VIF and FSIM. In our previous paper, the importance of demosaicing technique and ROI has been shown. This paper continues in this topic and implements new full reference objective metrics for the reconstructed image quality evaluation. The results reveal that the ROI controlled by bottom-up mechanism can be used for performance improvement.