My master´s thesis is concerned with the problems of traffic accidents involving public transport in Brno. The first part of my master´s thesis is concentrated on an analysis of the structure of the vehicle fleet of the Dopravní podnik města Brna, a.s. (DPMB). There is an evaluation of traffic accidents of the vehicles of Brno´s public transport in the second part, according to the kind of traction. An analysis of the causes of the most common accidents was carried out on the basis of the ascertained results. In the last part, my master´s thesis is concerned with a proposal of measures to reduce the accident rate.

Předložená disertační práce se zabývá experimentálním studiem modifikátorů tření a maziv pro temeno kolejnice, které jsou aplikovány do kontaktu kola a kolejnice za účelem optimalizace adheze a redukce hluku. Hlavním cílem práce bylo objasnit vliv aplikovaného množství a složení těchto látek na adhezi v kontaktu. Hlavní pozornost byla věnována zejména potencionálním hrozbám souvisejících s kriticky nízkou adhezí, která může nastat po aplikaci těchto látek. Experimentální studium probíhalo v laboratorních i reálných podmínkách, konkrétně v tramvajovém provozu. V případě laboratorních experimentů byl využit komerční tribometr a dvoudiskové zařízení umožňující simulovat průjezd vozidla traťovým obloukem. Kromě samotné adheze bylo při experimentech sledováno také opotřebení a míra hluku. Výsledky ukázaly, že maziva pro temeno kolejnice jsou schopna poskytovat požadované třecí vlastnosti, nicméně jejich chování je silně závislé na aplikovaném množství. V případě předávkování kontaktu dochází ke kriticky nízkým hodnotám adheze, které vedou k výraznému prodloužení brzdné dráhy. V případě modifikátorů tření bylo ukázáno, že chování těchto látek je výrazně ovlivněno odpařováním základního média. Výsledky také ukázaly, že nadměrné množství částic pro modifikaci tření může způsobit kriticky nízké hodnoty adheze. U obou výše zmíněných typů produktů byl prokázán pozitivní vliv na míru opotřebení a míru poškození povrchu, zatímco významná redukce hluku byla dosažena pouze v případech, kdy došlo ke značnému poklesu adheze. V závěru této práce jsou uvedena doporučení pro další výzkumné aktivity v této oblasti.

This paper contains an introduction that describes the current situation of the problem and its energy supply improvement. It discusses everything from power substations to trolleys which are fed through sections. There is a reference to the network operating deficiencies and possible solutions. The second part describes the development of these networks and their modernization in a growing city. It is verified by calculation if were our considerations good and proposed network will be normally reliable and capable. The final part deals with the economic balance of the project and its various alternatives. Development of energy networks and facilities cost many finance and these investments do not show immediately. Future will be paid off because as soon the changes come less problems may occur.

Master’s thesis deals with application of new suspension means for personal elevator instead of conventional steel wire rope includes calculation of traction. Followed by assessment of passive resistance generated by guiding elevator on guide rails and caused by various locations of suspension and guiding (car guide rails). In the last part of thesis contains a strength analysis of car frame by Finite elements method (FEM) in programme NX I-deas.

We used RUSI (rehabilitative ultrasound imaging) for measurement of abdominal and back muscle in different loading modes. Methods: We used diagnostic ultrasonography imaging for taking linear measurement of trunk muscles. We measured anterioposterior (AP) dimensions of lateral abdominal wall muscles- m. OE, m.OI, m.TrA and cross-section area (CSA) of lumbar m. multifidus. We compared two groups of sports-floorball players and sportsman using climbing and hanging (climbers, aerialists). We measured positions with compressive force (kneeling on all four with lifted knees) and with traction load (hang with upper limbs with flexion of lower limbs-with leg support and without). Study is made on 50 volunteers. Results: The pattern of thickness of abdominal muscles is same in all positions in both groups. The lowest is always AP thickness of m. TrA, wider is m. OE and the widest always m. OI. The resting thickness are in both groups almost in all cases the lowest. AP thickness in m. TrA in floorball players is only exception, there is lowest in hang without legs support. In all other case sis resting position always lowest. For m. OE are results same for both climbers and floorball players-the lowest thickness is in hang with legs support (floorball players 0,84 cm, climbers 0,87), greater activationis...

The main topic of the thesis is the design of single-track electrification of a direct current system of 3 kV and an alternating current system of 5 kV 50 Hz and then economically evaluate it over a period of 30 years. The work deals with basic traction systems and also deals with the calculation of main parameters of electric trains. The thesis describes in detail the procedure for the design of the electrification of the track and a partial introduction to the simulation programs that were used for energy calculations.

This thesis presents a proposal of newly designed concept for travel hydraulic circuit of vibratory single drum roller ASC 110. The maximum machine gradeability was chosen as the main parameter for hydraulic circuit proposal. After selecting the new hydraulic travel concept, suitable hydraulic components have been selected. Length and local losses for two different machine speeds were calculated for sufficient hydraulic circuit design. Hydraulic losses have also been calculated for use in different climatic conditions. A new machine cooling concept has also been proposed. Heating and cooling curves of hydraulic circuit were calculated. For the purpose of comparing gradeability and energy balance of the newly designed travel concept compared to the existing one currently in mass production, both machines were fitted with measuring points. On both machines were measured for example, pressure, flow and temperature in each hydraulic circuit branch and others. From the time dependencies of the above-mentioned parameters it was possible to determine the energy efficiency of the newly designed concept. To assess the maximum gradeability, the slope of the hill was measured. Comparing the two machines, it has been found that the two hydraulic circuit solution has significantly improved traction properties in demanding machine applications, especially when driving uphill and downhill. This concept also affects less fuel consumption and places less demand on the hydraulic oil cooler due to its energy efficiency.

This work deals with creation of an exact mathematical model of a traction drive with low-voltage induction machine (28 V) which is fed from accumulators. This model was developed in MATLAB – Simulink and consists of induction machine model, inverter model and load model. Vector Control was added to models connected together. This complex model allows considering many effects into simulations. These effects are commonly neglected, although they have significant influence on drive behaviour, especially by using low-voltage machine. It is impact of magnetic circuit saturation, impact of temperature and skin effect on winding resistance, impact of inverter nonlinearities such as on-state voltage drops on switching elements, dead times and transistors switching times. The attention was paid to determination of losses in drive parts. The correctness of the model was verified at laboratory workplace established for this purpose. The laboratory drive can be controlled by a microprocessor or by using MATLAB and dSPACE application. The influence of compensations of inverter nonlinearities and DC-link voltage ripple on higher harmonics of inverter output currents was analyzed. Furthermore, the control, which decreased resistive losses, was solved.

The work analyzes the operation of hybrid substations. The first chapter provides an analysis of domestic traction systems and describes in detail specific station. The next chapter follows the first in a way in which obtained parameters are converted to parameters suitable for the simulation program and presents its results. The third chapter discusses the serial communication used in one switchgear and about voltage regulator that controls one high voltage field. The last chapter verifies the simulation results obtained from the second chapter with real measurement and direct comparison is also included.