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Copyright of Česká a Slovenská Neurologie a Neurochirurgie is the property of Czech Medical Association of JE Purkyne and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the paper is to determine the most suitable operational redundant assets and asset structure for a manufacturing enterprise. They are determined by the financial analysis of ratios, vertical and horizontal analysis, and the calculation of Altman Z-score. The recommended sizes of activity ratios are: the turnover of total assets should be equal to the value of 1, the time of inventory turnover should be as short as possible, the turnover of inventories should be as large as possible, the time of debt collection should be the shortest possible, the due date of fulfilling obligations should be equal to 2 or higher. The ratios are compared with the sector and the position of enterprise is assessed. The limit of the research is the incapability to determine the best asset structure, but only the best possible one, on the basis of comparing with the sector that sets the bar in a specific field. Every enterprise aspiring to be competitive should meet the sector standards, at least.

Copyright of Czecho-Slovak Pediatrics / Česko-Slovenská Pediatrie is the property of Czech Medical Association of JE Purkyne and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of present work is focused on determining accuracy of the measurement using the Particle Image Velocimetry based on an analysis of synthetic Uniform flow test and Couette flow test. We focused on testing the Standard Cross Correlation algorithm and interdependence between the several metrics based on the ratio signal and noise peak and the measurement accuracy at each point. This work is describing the influence of the new corrected metric that is corrected by a displacement measured in the last iteration, detected mean density of the particles and the velocity gradient. Newly proposed method of calculating the metric, Lost of Particle Ratio, is based on the determination of the magnitudes of two correlation peaks. In this work there is defined and compared another metric based on the result of synthetics data test which is based on determination of main parameters as number of particles, gradient in interrogation area and displacement of particles calculated in the last step of correlation. For all presented metrics the relationship is between the metrics and the accuracy.

Measurement of velocity fields by PIV method is often limited by the scale of the measured model. This is doubly true for the stereo PIV method. Problems of measurement in small (but still macroscopic) scales are associated with optical distortions in the optical path of the camera. Additionally, there is a calibration problem for stereo PIV. Therefore, this paper is devoted to the description of PIV methodology for measurement in small geometrical scales. The idealized transparent model of hemodialysis vascular access was used in this paper. This model had realistic vascular access dimensions (6 mm in diameter). A special working blood-mimicking fluid (BMF) was mixed with a refractive index matching that of the model. The refraction and distortion of light passing through the interface between the model and the fluid was so small, that it was possible to calibrate the stereo PIV outside the measured model. The accuracy of this calibration is discussed and verified by measuring the velocity field on a straight section of the vascular access model for laminar flow.

In our work, we focused on measuring the performance characteristics of a test hydrogen fuel cell with an open cathode. The aim of the work was to verify the effect of the mass flow through the fuel cell on the power output as a function of the current density and voltage on the fuel cell. A test bench capable of testing fuel cells up to 2000 W was used to measure the power characteristics. The test fuel cell was composed of three cells and its total membrane area was 100 cm2. A PIV measurement system was used to measure the mass flow. The mass flow measurement was performed at the inlet of the fuel cell. The measurements included the determination of the inlet temperature distribution using a thermal imaging camera. The presented measurements were performed for two configurations with original and optimized diffuser at the inlet of the fans. Finally, the effect of mass flow and overall thermal management on the fuel cell performance is discussed, including the effect of the newly designed diffuser.

Visualization of internal flow or PIV measurements in areas of real pipe elements is a method commonly used in flow studies. For these applications, transparent models with very complex internal geometries are required. Key features of the model are the high-quality optical access, which ideally allows to obtain image of the whole measured area without deformation and with noise suppression. The technology of 3d printing in combination with casting allows the production of almost any type of transparent models of piping elements. Models produced using this technique have almost ideal optical properties. By using index-matching fluid, optical distortions as well as reflections and refractions of light on the inner edges of the model are suppressed. The paper presents the results of visualization and 2D PIV measurements in the model of the globe valve with adjustable valve plug. The valve’s inner geometry was rapid prototyped using a water-soluble material and casted with clear silicone Sylgard 184 under vacuum. The model exhibits excellent optical properties for PIV measurements, especially in the vicinity of walls.