National Repository of Grey Literature 133 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
The effect of sustained military operational stress on military-related physical and cognitive performance.
Pustka, Martin ; Maleček, Jan (advisor) ; Michalička, Vladimír (referee)
age of 20.9 ± 1.8 years, studying in the Military field at the Faculty of Physical Education and : No significant declines in physical performance were observed within the PRE1 → → POST3 period were nearly identical. The in the PRE1 → POST3 period, with the experimental group intensively in all performance tests within the PRE1 → POST3 period, reaching up to 42.1% differences within the PRE1 → POST3 period. However, due to the small r
Cyclic plasticity and low-cycle fatigue resistance of materials prepared by the ColdSpray method
Brůža, Jaromír ; Šulák, Ivo (referee) ; Zapletal, Josef (advisor)
In the theoretical part, the diploma thesis focuses on Cold spray technology and parameters affecting the efficiency and quality of deposition. Next, there is an introduction to the fatigue process of materials. The theory is concluded with a summary of the current knowledge regarding materials created by Cold spray technology in the field of fatigue. In the practical part, volumetric bodies were created from the material EN AW7075. Specimens for tensile and fatigue tests were cut from the bodies by electrosparking. From the material and powder, metallographic cuttings were created for the determination of porosity using Archimedes’ principle, hardness according to Vickers and evaluation of EDS and EBSD analysis. The basic mechanical properties were determined from the tensile tests and the Wöhler-Basquin parameters were determined from the fatigue tests along with the life curve. Subsequently, a fractographic analysis of fracture surfaces using SEM took place.
Design caclulation of fatigue of tubular condenser
Cablková, Zuzana ; Vincour, Dušan (referee) ; Pernica, Marek (advisor)
The diploma thesis is devoted to the design of the fatigue calculation of the tubular steam condenser with fixed tube sheets, which is in operation as a safety equipment for the steam condenser from the turbine. This device is loaded with temperature and pressure that induces tension. Due to the possibility of frequently starting it up to the operational state and going down to the rest state, stress cycles can occur. The practical part of the thesis is the design calculation, carried out according to ČSN EN 13445–3 standards using the finite element method, abbreviated FEM. The theoretical part of the diploma includes a search of available standards for evaluating the fatigue life of heat exchangers, basic knowledge regarding the issue of fatigue damage and cases of real fatigue damage in practice.
Spark-ignition engine design for hybrid passenger car
Smejkal, Jan ; Dlugoš, Jozef (referee) ; Drápal, Lubomír (advisor)
This diploma thesis deals with design of four-cylinder spark ignition naturally aspirated engine with indirect fuel injection for hybrid passenger cars. The thesis begins with research of engines that meet the requirements of the thesis assignment. The research is followed by design of the engine, where the main components are described in detail. The last part deals with FEA analysis of the connecting rod which is followed by analytical computation of high cycle fatigue by the LSA method.
Využití respirační fyzioterapie u pacientů po prodělání onemocnění Covid-19
Covid-19 disease is caused by a new type of coronavirus, technically called SARS-CoV-2, which had not been identified in humans before December 2019. It is a droplet- and aerosolborne infectious disease mainly affecting the nasopharynx and lungs. Nowadays, numerous people suffer from the after-effects of having contracted Covid-19, the so-called post-covid syndrome. This is a set of different symptoms that can provide in essence the whole body. The most common complaints include shortness of breath and a persistent cough, deconditioning, headaches, back and chest pain to varying degrees, weakness and fatigue, as well as psychological problems such as anxiety and depression, concentration disorders and insomnia. From a physiotherapy perspective, these symptoms can be modified to varying degrees. For example, directly respiratory difficulties - influencing lung function, respiratory muscles, restoring the correct breathing stereotype. However, we can also influence posturalarticular functions and posture. The aim of the bachelor's thesis is to describe the most common health problems of patients after Covid-19 infection and to suggest appropriate physiotherapy approaches for the identified difficulties. In particular, the thesis focuses on breathing difficulties and the possibility of influencing them with respiratory physiotherapy techniques. A qualitative research strategy was chosen, the research population consisted of five adult patients, and during the course of the research the number was reduced to four probands. The condition for inclusion in the research was a history of SARS-CoV-2 infection, after which patients continued to experience some persistent health problems. Physiotherapy interventions were targeted to optimize respiratory function using selected respiratory physiotherapy techniques. The results were processed by comparing the input and output kinesiological analysis, measuring inspiratory and expiratory mouth pressures using the MicroRPM device and measuring the patient's lung function using spirometry. Improvements were achieved in walking ability, postural-respiratory diaphragmatic function, chest mobility, respiratory pressure values and subjective perception of health status. Some improvement in lung function was also noted by spirometry.
Fatigue Analysis of Steel Welded Joints
Venzara, Mikuláš ; Poduška,, Jan (referee) ; Gratza, Roman (advisor)
The master thesis deals with the analysis of steel welded joints in high-cycle fatigue in building structures. The theoretical part outlines the basic theory and some approaches used for fatigue design of structures. The practical part deals with the studies of welded joints for different fatigue methods using the ANSYS software system.
The Verification of the Use of the Heart Rate Variability in the Management of Training Process in Adolescent Mountain Bikers
Cross-country Olympic (XCO) is one of the endurance sports. The training process of mountain bikers is very demanding because the rider must be complex in endurance and anaerobic skills. Alfa and omega of the training process is a periodization of training load and recovery. Heart rate variability (HRV) can help us assess body's condition and readiness for training. In the practical part of the work, an experiment was carried out, which was attended by eight adolescent mountain bikers. The intervention took place during the training camp. The total intervention time was four weeks. The participants were randomized into two groups. The first experimental group (ES) (n = 4) was a graduated training camp with a heart rate variability guided training load. The second group was a control group that used a classical predefined training plan. For evaluation of HRV training efficiency a VO2max test and 20 minutes time trial (20TT) on an ergometer were used. The results showed an improvement in mean power output during 20TT in the experimental group (PRE 303.5 W; POST 317.5 W) and relative values (PRE 4.58; POST 4.68 On the other hand, there were no changes in average power (PRE 308 W; POST 305.7 W) and relative values (PRE 4.20; POST 4.20 From a statistical point of view, there was no effect of HRV training on performance indicators (p <0.05). Our experiment failed to confirm the usefulness of HRV training for cyclists.
Analysis of the size of the annual improvement of the performance of elite adolescent runners in the Czech Republic
The scope of the work is the analysis of the size of annual improvement of the Czech, or more precisely Czechoslovak elite runners who recorded their performances on medium and long distance runs from the post-war period to the present. The work is divided into several parts. The analytical part deals with the theory of medium and long distance runs in terms of history and development of training methods, characteristics and technique of running, using the specialized literature. There are other related topics focusing on runners, such as the physiological basis of training, sports training, fatigue and its regeneration. In the synthetic part, the researched set of runners is selected, namely the twenty best-performing Czech, or more precisely Czechoslovak athletes running medium and long distances. The analysis of the necessary data from athletic tables, yearbooks and other encyclopedic literature is performed for this selected set of runners. Based on the obtained data of individual performances in each year, the largest increase in the performance of each selected runner is statistically evaluated. Data concerning the placement of the runners in the youth categories were also searched. The results will answer the selected scientific questions that can be beneficial for the optimal training strategy in youth training.
The verification of usability of the heart rate variability in the training process for cyclists
Alternation of intensity and rest in the right proportion is crucial for the development of sports performance. The correct timing of the practice can be simplified by monitoring heart rate variability. The aim of the thesis is to verify connection between the current readiness to give a sport performance and HRV. The verification had been performed using HRV monitoring and stress tests. The stress tests were undertaken in Functional Load Diagnostic Laboratory belonging to the Department of Sport Studies at the University of South Bohemia. The experiment had been running for two months. The participants of the experiment were two cyclists of XC category. One of the limiting factors of the experiment is the number of participants. The statistical significance of values was gained by comparing spirometry and spectral analysis of heart rate variability results. Correlation of values of sympathetic nervous system stimulation and minute ventilation can be considered as statistically important. Connections of only one of two experiment participants were statistically important for the thesis. The first of the probands showed 32 statistically important correlations out of 140. The second of the probands showed 11 statistically important correlations out of 140. More statistically significant correlations have been proven in cyclist with higher level of performance. The connection between the level of performance and the HRV, the importance of which is particularly in determining the level of compensation, has been confirmed at least to some extent.
Bond between FRP reinforcement and concrete
Januš, Ondřej ; Hradil, Petr (referee) ; Materna, Alois (referee) ; Štěpánek, Petr (advisor)
Recently, FRP (fibre reinforced polymers) materials are increasingly used in concrete structures, both for the strengthening of existing structures and as an internal reinforcement of concrete elements. It is due to convenient mechanical and physical properties of this kind of material. However, the use of these innovative materials as a reinforcement of concrete structures often requires a modification of the design process used for steel reinforcement. At present, a large number of bridge structures are in a very poor condition and require remediation due to corrosion of the steel reinforcement. Composite reinforcement appears to be a suitable alternative to steel reinforcement in these application areas. However, since bridge decks are directly exposed to repeated traffic loads, fatigue assessment is an important and often crucial part of the design. The number of studies dealing with the fatigue behaviour of internal FRP reinforcement is currently very limited. In particular, there is currently no study that sufficiently deals with the comprehensive determination of the effect of fatigue loading on the bond between FRP reinforcement and concrete. The doctoral thesis deals with the design of concrete elements reinforced with modern composite FRP reinforcement exposed to high-cyclic (fatigue) loading. Thanks to the performed extensive experimental programme, it was possible to determine the permissible limit values of fatigue load to ensure the required fatigue life. Based on these limiting values, the design and subsequent fatigue testing of full-scale concrete roofing slabs intended for aggressive environments was performed.

National Repository of Grey Literature : 133 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.