National Repository of Grey Literature 305 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Validity of commercially available smartwatches when estimating energy expenditure
Kopecký, David ; Pokorný, Jan (referee) ; Řehák Kopečková, Barbora (advisor)
Metabolic rate is an energy quantity. Its value is a key input not only in thermophysiological models, but also in the calculation of heat stress indices or complex models predicting a person's thermal sensation. With the dynamic development of technology, sporttesters are able to estimate energy expenditure, among other things. It is a non-invasive method of estimating energy expenditure, or metabolic rate, using associated body functions to predict it. This work deals with the validity of the accuracy of metabolic rate estimation using the Garmin Fenix 6X Pro sporttester in comparison with indirect calorimetry. The accuracy of the metabolic rate estimation was tested for the activities of lying down, administrative work and cycling with regulated mechanical resistance of 100 and 150 W. 15 male subjects aged 28 ± 5 years, with a weight of 83.2 ± 13.5 kg and a height of 180 ± 7 cm participated in the study. In terms of the results, it is possible to observe a lower accuracy of prediction of metabolic rate for low-intensity activities, with the resulting MAPE being around 19-43 %. On the other hand, for activities with moderate activity, the prediction of the metabolic rate by the used sporttester proved to be sufficiently accurate, with a resulting MAPE in the range of 6–8 %.
Heat transfer from the surface of the human body - validation of a CFD thermal manikin model
Kuruc, Jan ; Pokorný, Jan (referee) ; Fišer, Jan (advisor)
This master thesis is focused on CFD simulation of heat transfer from a thermal manikin in a calibration environment and its subsequent validation based on the experiments already performed in the master thesis of Ing. Fojtlín and Ing. Hrubanová. The main objective of the work is to find and test a suitable combination of physical models and set boundary conditions in the simulation model so that the actual heat transfer and airflow processes from the validation experiments are faithfully simulated. In the course of the work, 7 cases were simulated based on individual measurements made during the experiments. The calculated heat transfer coefficients of the thermal mannequin segments for each simulated case can be considered as the main results of the simulation. For the experiment of Ing. Fojtlín, these are the heat transfer coefficients by radiation and convection. For the experiment of Ing. Hrubanová, the total heat transfer coefficients for a manikin with five selected clothing assemblies were determined. Validation was performed by comparing the simulated and experimentally determined values of heat transfer coefficients. Based on the comparison, the developed simulation model could be declared validated.
Comparative analysis of light holder lifetime assessment methods
Holeta, Aleš ; Pokorný, Jan (referee) ; Vosynek, Petr (advisor)
This thesis addresses the topic of determining the fatigue life of a thin-walled holder fender and flashlight under variable loads. The aim of the thesis is to make a search study on the fatigue life of welded parts with respect to the thin-walled design of structures. The main objective is to evaluate the suitability of using different methods of fatigue life assessment on the holder fender and flashlight. The calculated fatigue lifetimes are confronted with experimentally obtained fatigue life-times. The fatigue lifetimes are determined by methods evaluating welded joints based on structural stresses and notch stresses. Finite element analysis was performed in the open-source programs Salome and Code_Aster. The modelling of the holder fender and flashlight geometry was performed at several levels. Based on the results, the most efficient method for the design of welded parts is the structural stress linearization method (also called “master S-N curve method”), which achieves comparable results to the effective notch stress method (considered as a reference), but with a multiply lower time consumption.
Development of Algorithm for Computational Modelling of Pivoted-Pad Journal Bearings
Pokorný, Jan ; Křupka, Ivan (referee) ; Šimek,, Jiří (referee) ; Návrat, Tomáš (advisor)
The presented work deals with the calculation of stiffness and damping coefficients of hydrodynamic tilting-pad journal bearings. For this reason, a computational model of static and dynamic characteristics of these bearings is developed. The calculation is based on the solution of the generalized Reynolds equation simultaneously with the 2D energy equation for both the lubricant film and the pads. As a result, the changes in viscosity and density of the lubricant across the film thickness can be considered. The effect of turbulence is reflected by correction factors. Other influences, such as lubricant mixing, deformation and tilting of the pads, are also included in the calculation. The numerical solution using the finite volume method is programmed in Python. The static equilibrium position of the bearing is found by the efficient bounded Anderson method, which was chosen after comparison with other selected methods. Based on the equilibrium position of the bearing, the stiffness and damping are calculated using the central difference method with the inclusion of flexibility of the pivots. The results of static and dynamic characteristics of the bearing of the selected parameters are presented. Furthermore, the obtained results of the calculations are verified with experimental data taken from the literature and also with in-house measurements. A good agreement between calculations and experiments has been achieved.
Cardiorespiratory fitness in professional pole dancers
Trnková, Jiřina ; Herdová, Barbora (advisor) ; Pokorný, Jan (referee)
This thesis is devoted to cardiorespiratory fitness in professional pole dancers. The theoretical part describes the specifics of pole dance exercise and its effect on human body. The thesis further contains the introduction to exercise physiology and diagnostics. Methods: 8 performance female pole dancers competing in professional/elite category took part in the study. All probands completed two exercise tests - a laboratory and a field exercise test. Probands' cardiorespiratory fitness was assessed in a laboratory maximal exercise test. In field exercise test we investigated the exercise intensity in a simulated pole sport competition. Exercise variables were monitored in both tests using a portable metabolic analyzer VO2 Master Pro. Results: The average values during maximal spiroergometry test were VO2peak 46,1 ml/min/kg a Wpeak 3,7 W/kg. Probands' cardiorespiratory fitness was above average ( 0,03 < p < 0,04). The average pole dance performance intensity was 89 % TFmax (158 bpm) and 79 % VO2peak (36,2 ml/min/kg), the peak values were 96 % TFmax (178 bpm) and 110 % VO2peak (50,6 ml/min/kg). More than a half of the pole dance performance was performed above the intesity of anaerobic threshold (p = 0.019). Conclusions: Performance pole dancers are more fit than the average population (VO2peak is...
Evaluation of effect of mobile application CF Hero on compliance of inhalation treatment and respiratory physiotherapy of pediatric and juvenile patients with cystic fibrosis
Jirásek, Martin ; Plešková, Jana (advisor) ; Pokorný, Jan (referee)
This diploma thesis deals with the adherence to inhaled treatment, its measurement, telemedicine and telerehabilitation and the possible use of the CF Hero mobile app in paediatric patients with cystic fibrosis. In the theoretical part, it presents knowledge about cystic fibrosis, adherence to treatment in patients with cystic fibrosis and possibilities of its measurement, telemedicine and telerehabilitation. The practical part describes the CF Hero mobile app, which has been the target of measurements on several patients. At the same time, a questionnaire was developed focusing on satisfaction with the use of this mobile application. Methods: The practical part was conducted as a multicentre prospective cross-over study investigating the effect of the CF Hero mobile app on adherence to inhaled treatment, respiratory quality of life and chest excursion The evaluation was conducted over a 6-month period, with the primary objective being to measure the amount of exhaled solution relative to the prescribed amount. Simultaneously, each patient underwent 3 identical examinations. These examinations included spirometric testing (FEV1, FVC, MEF50), measurement of chest excursion (axillary, mesosternal, xiphoid) and quality of life assessment using the CFQ-R questionnaire. It also included measurement of...
Fylogeneze a taxonomie vybraných druhů sinic čeledi Merismopediaceae s využitím metody single cell sequencing
POKORNÝ, Jan
Thanks to new molecular methods, which have been used for revision of many traditional cyanobacterial taxa, their real systematic positions have become clearer. Merismopediaceae is a relatively understudied group of Cyanobacteria, therefore many subordinate taxa have not been sufficiently molecularly reviewed. In this thesis standard molecular methods of the polyphasic approach were used on environmental isolates as well as cultured strains of Merismopediaceae taxa. Subsequent phylogeny analysis based on 16S rRNA gene shows the polyplyly of genera Merismopedia and Eucapsis. The thesis also includes the very first molecular evidence of the taxonomic position of the genus Microcrocis.
XXIV Czech-Polish seminar: Structural and ferroelectric phase transitions: Book of abstracts and program
Pokorný, Jan ; Bubnov, Alexej ; Janovská, Marie
This is the Book of Abstracts for the XXIV Czech-Polish Seminar (CPSEM-2022 conference) held in Harrachov (Czech Republic) on May 23 - 27, 2022. The special objective of the conference is expressed in the conference subtitle: Structural and Ferroelectric Phase Transitions. The continuous worldwide interest to this conference series is proving that it has a respected position within the series of International/European conferences covering all interdisciplinary field of the research related to structural and ferroelectric phase transitions. At the CPSEM-2022 conference there were about 100 participants from 10 countries delivered 8 tutorial lectures for early stage researchers, 8 invited lectures and selected 34 oral contributions. More than 55 posters were presented during two poster sessions.
Application of Hamilton’s Equations in Solving Oscillation of Multi-Degree-of-Freedom System
Sikora, Ondřej ; Houfek, Lubomír (referee) ; Pokorný, Jan (advisor)
The thesis is mainly focused on the comparison between Hamiltonian and Lagrangian formulations of classical mechanics. This research was used in order to derive equations of motion of a quarter car model and use them to simulate and analyze car body vibrations based on road irregularities.
Use of the DIC method in solving basic problems of solid mechanics
Hrůza, Vlastimil ; Pokorný, Jan (referee) ; Ščerba, Bořek (advisor)
This bachelor’s theses deals with the solution of basic problems of solid mechanics using digital image correlation. The research part of the thesis presents some of the optical methods used for deformation measurement, digital image correlation in particular, whose history, principles, limitations and utilizations are described in detail. In the practical part of the theses, three experiments are carried out, which are then evaluated using digital image correlation and the results are compared with the created computational models. In the first experiment, strain on the tensile test specimens with notches is measured, the second experiment is focused on measuring strain when bending curved beams and in the final experiment, natural frequency of a fork produced by 3D printing is determined.

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