The objective of the thesis is to provide a view of the situation in high-speed Internet connection in the Czech Republic. At the beginning we present a history of internet and describes in particular the most frequently used technology of high-speed connectivity to the Internet. This is followed by a comparison of the current supply and demand in a market of Internet connection in the Czech Republic. This study not only compare technological aspects, but takes into consideration the economic situation, government regulations and changes from 2009 as well. Finally, there is a summarization and an evaluation of the results and a reflection on possible future on a market of high-speed connection in Czech republic.

The impact phenomena of high velocity micron-size particles, although commonly considered and described as detrimental in numerous engineering applications, can be used in a beneficial way if properly understood and controlled. The Cold Gas Dynamic Spray (CGDS) process, known as a surface modification, repair and additive manufacturing process, relies on such high velocity impacts. In the process, solid particles are accelerated by a supersonic gas flow to velocities up to 1200 m/s and are simultaneously heated to temperatures lower than their melting point. When propelled under proper velocity and temperature, the particles can bond onto a target surface. This bonding is caused by the resulting interfacial deformation processes occurring at the contact interface. Hence, the process relies heavily on the gas/particle and particle/substrate interactions. Although numerous experimental and/or numerical studies have been performed to describe the phenomena occurring during particle flight and impact in the CGDS process, numerous phenomena remain poorly understood. First, the effect of substrate surface topographical condition on the particle deformation and ability to successfully adhere, i.e. atomically and/or mechanically, has not been thoroughly investigated such that its influence is not well understood. Another aspect of the process that is generating the largest gap between experimental and numerical studies in the field is the lack of particle in-flight temperature measurements. Obtaining such data has proven to be technically difficult. The challenges stem from the short particle flight time, low particle temperature and small particle size preventing the use of established thermal spray pyrometry equipment. Relatedly, lack of such measurements precludes a proper experimental study of the impact related phenomena at the particle/substrate interface. As a result, the effect of particle size dependent temperature on overall coating properties and atomic bonding relies currently on estimates. Finally, the effect of particle impact characteristics on interfacial phenomena, i.e. grain size and geometry, velocity/temperature, and oxide scale thickness, on adhesion and deformation upon single particle collision has also been scarcely studied for soft particle depositions on hard substrate. Hence, the current research work aims at studying fundamental aspects of particle/gas heat transfer and particle/substrate impact features in goals to improve the understanding of the CGDS process. Different surface preparation methods will be used to create various surface roughness and topographical features, to provide a clear understanding of the target surface state influence on coating formation and adhesion. Additionally, new equipment relying on novel technology, i.e. high-speed IR camera, will be utilized to obtain particle in-flight temperature readings with sequence recordings. Subsequently, the experimental particle in-flight temperature readings will be used to develop a computational fluid dynamics model in goals to validate currently used Nusselt number correlations and heat transfer equations. The particle size-dependent temperature effect on the particle’s elastic and plastic response to its impact with a targeted surface and its ability to successfully bond and form a coating will be studied experimentally. A thorough CFD numerical work, based on experimental findings, will be included to provide full impact characteristics (velocity, temperature, size and trajectory) of successfully deposited particles. Finally, the numerical results will be utilized in the ensuing study to correlate single particle deformation, adhesion and interfacial features to impact characteristics. A finite element model will be included to investigate the effect of particle size dependent temperature on single particle interfacial pressure, temperature and bonding ability.

The purpose of this research is to analyze the use of the public train usage in Central Florida to determine the feasibility of high-speed rail usage in the future. This study will be split into parts and expanded upon. The first part will observe rider perspective, values, and issues regarding rail transportation as is available in Central Florida. In further installations, which will be conducted separately from this thesis, there will be an analysis of the providers of rail transportation. It is hypothesized that there will be a moderate demand for rail transportation used by the public. Original: The main purpose of this descriptive research is to describe the feasibility of high speed rail in the United States. Feasibility is defined as the determining factor in the sustainability of a project. In the case of this research study, high speed rail is the project and is defined as a specialized railroad system, including dedicated tracks and specialized rolling stock, that travels upward of 125mph. It is hypothesized that the feasibility in high speed rail is high due to the current functioning transportation systems in Florida.

High-Speed Railway (HSR) technology requires the deployment of noise barriers to mitigate noise pollution affecting nearby residents. As train speeds increase, so does the magnitude of aerodynamic effects such as aerodynamic noise and the pressure on these barriers, meaning that these structures require robust sound insulation and structural load-bearing capacities. Train-induced aerodynamic loads must therefore be accounted for in the structural design of HSR noise barriers, and accurate characterization of these loads is vital for ensuring noise barrier performance and safety. Current European standards primarily evaluate aerodynamic loads on noise barriers based on train speed and the distance to the track centre. However, geometric differences between high-speed trains (HSTs) from different countries and regions necessitate the validation and potential revision of existing load calculation models. This thesis aims to enhance the characterization of train-induced aerodynamic pressure on HSR noise barriers and develop more accurate models for its calculation, focusing on the most common barrier type—vertical noise barriers. Initially, a thorough literature review was conducted to assimilate current knowledge on this topic and pinpoint existing gaps and challenges. Multiple factors including the geometric properties of trains and the heights of noise barriers were then analysed using computational fluid dynamics (CFD) simulations to evaluate their impact on the train-induced aerodynamic pressure on vertical noise barriers. Finally, the suitability of existing pressure calculation models was evaluated using literature data and a modified calculation model building on the EN 14067-4 model was developed.  A key finding is that the general applicability of existing pressure calculation models is limited because of the wide variation in HST geometries and noise barrier heights. The amplitude of train-induced aerodynamic pressure on vertical noise barriers increases with train height and width but decreases as nose length increases. While taller noise barriers experience greater aerodynamic pressures, the in-crease in pressure with barrier height is not significant. The proposed modified pressure calculation model that accounts for train geometry and the height distribution coefficient predicts the train-induced aerodynamic pressure on vertical noise barriers more accurately than existing models and could thus improve the structural design and safety of HSR noise barriers across a wide range of conditions.

Vocal folds are the twin in-folding of the mucous membrane stretched horizontally across the larynx. They vibrate modulating the constant air flow initiated from the lungs. The pulsating pressure wave blowing through the glottis is thus the source for voiced speech production. Study of vocal fold dynamics during voicing are critical for the treatment of voice pathologies. Since the vocal folds move at 100 - 350 cycles per second, their visual inspection is currently done by strobosocopy which merges information from multiple cycles to present an apparent motion. High Speed Digital Laryngeal Imaging(HSDLI) with a temporal resolution of up to 10,000 frames per second has been established as better suited for assessing the vocal fold vibratory function through direct recording. But the widespread use of HSDLI is limited due to lack of consensus on the modalities like features to be examined. Development of the image processing techniques which circumvents the need for the tedious and time consuming effort of examining large volumes of recording has room for improvement. Fundamental questions like the required frame rate or resolution for the recordings is still not adequately answered. HSDLI cannot get the absolute physical measurement of the anatomical features and vocal fold displacement. This work addresses these challenges through improved signal processing. A vocal fold edge extraction technique with subpixel accuracy, suited even for hard to record pediatric population is developed first. The algorithm which is equally applicable for pediatric and adult subjects, is implemented to facilitate user inspection and intervention. Objective features describing the fold dynamics, which are extracted from the edge displacement waveform are proposed and analyzed on a diverse dataset of healthy males, females and children. The sampling and quantization noise present in the recordings are analyzed and methods to mitigate them are investigated. A customized Kalman smoothing and spline interpolation on the displacement waveform is found to improve the feature estimation stability. The relationship between frame rate, spatial resolution and vibration for efficient capturing of information is derived. Finally, to address the inability to measure physical measurement, a structured light projection calibrated with respect to the endoscope is prototyped.

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper introduces a study of the feasibility and initial hardware design for transmitting data over aircraft power lines. The intent of this design is to significantly reduce the wiring in the aircraft instrumentation system. The potential usages of this technology include Common Airborne Instrumentation System (CAIS) or clock distribution. Aircraft power lines channel characteristics are presented and Orthogonal Frequency Division Multiplexing (OFDM) is introduced as an attractive modulation scheme for high-speed power line transmission. A design of a full-duplex transceiver with accurate frequency planning is then discussed. A general discussion of what communications protocols are appropriate for this technology is also provided.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2007. / The successful use of hydrofoil systems on catamarans, such as the Hysucat, led to the development of a similar foil system for a high speed trimaran. Firstly a mathematical model was developed to calculate the equilibrium planing conditions of a planing trimaran. This was then used in the hydrodynamic design of a fully planing trimaran with a design speed of 65 kn. The mathematical model was then modified to include the effects of added hydrofoils. This model was then used to design a hydrofoil support system for the planing trimaran. Towing tank tests were then performed on a scale model of the boat, with and without the supporting hydrofoil system. This was done to verify the theoretical design and to gather resistance data, which could then be compared to other boats. The results showed a notable improvement in efficiency of the boat with the addition of foils. The conclusion was made that with the addition of a well-designed foil system, hull efficiencies similar to that expected for the Hysucat, can be attained when the foil system is added to the trimaran. As this work was focused mainly on the high-speed performance of the boat, it is not certain how the boat will perform through the speed-range. It is therefore recommended that further testing be done, to determine the performance of the boat at lower speeds.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / With the advent of high-speed parallel-to-serial conversion interface standards reaching the 1.6 gigabit per second region, it is now possible to remote entire telemetry tracking systems over long distances without the need to maintain receivers, combiners, computers and antenna control units at the pedestal. In addition, it will soon be possible to digitize the RF signal(s) with high-speed flash-video analog-to-digital converters and transfer the data over these same links. This coupled with the improvements in fiber-optic L.E.D. and laser transmitters/ receivers and the constantly decreasing cost of fiber-optic cable, will allow for the eventual elimination of copper cabling for these interfaces. This will net a cost savings for the end user, provide for easier installations and increase the reliability of the overall system. This paper gives a brief history of the development of high-speed fiber-optic interface links, then expands into current interface standards and their utilization (such as MIL-STD-1553B, fiber data distributed interface (FDDI), HIPPI, etc.). Finally, a glimpse into the future of telemetry systems and the possibilities to soon be realized as major manufacturers of fiber-optic interfaces push well into the gigabit region. Topics include: • Replacement of existing copper cables between controller and pedestal using fiber-optic cable with interfaces that are not software-based intensive (black boxes); • Multiplexing pedestal control and status lines, RF feed commands, scan reference signals, and boresite video camera control; • Connecting and controlling multiple controllers and/or pedestals through one common interface cable; • Operating multiple tracking stations through one remote antenna controller; • Digitized RF telemetry signals sent along with pedestal, feed, video commands and status.

The Swedish Transport Administration has been giving the task to set up a new standard for concrete slabs for the new high-speed railway in Sweden. They are demanding that the concrete slabs must be dimensioned according to the German Beton Kalender 2000. This report will explore the results when dimensioning a slab track, according to the German Beton Kalender 2000. Moment capacity, deformation, and crack width are calculated according to two structural theories, namely slab and beam theory, and a comparison between the two methods is presented.

Master of Science / Department of Mechanical and Nuclear Engineering / B. Terry Beck / Mohammad H. Hosni / Cavitation is the change of a liquid to a two-phase mixture of liquid and vapor, similar to boiling. However, boiling generates a vapor by increasing the liquid temperature while cavitation generates vapor through a decrease in pressure. Both processes are endothermic, removing heat from the surroundings. Both the phase change and heat absorption associated with cavitation provide many engineering applications, including contributing to a new type of refrigeration cycle under development. Cavitation can occur at or below the vapor pressure; conditions that delay cavitation and allow for a metastable liquid are not well understood. A converging-diverging nozzle was designed and fabricated to create a low pressure region at the nozzle throat. The converging section of the nozzle increased the water velocity and decreased the pressure, according to Bernoulli’s principle. A cavitation front was formed slightly past the nozzle throat. The cavitation location suggested that the water was metastable near the nozzle throat. Flow through the system was controlled by changing the nozzle inlet and outlet pressures. The flowrate of water was measured while the outlet pressure was lowered. The flowrate increased as the outlet pressure dropped until cavitation occurred. Once cavitation initiated, the flow became choked and remained constant and independent of the nozzle outlet pressure. High-speed imagery was used to visualize the flow throughout the nozzle and the formation and collapse of cavitation in the nozzle’s diverging section. High-speed video taken from 1,000 to 35,000 frames per second captured the formation of the cavitation front and revealed regions of recirculating flow near the nozzle wall in the diverging section. Particle Image Velocimetry (PIV) was used to measure the velocity vector field throughout the nozzle to characterize flow patterns within the nozzle. PIV showed that the velocity profile in the converging section and throat region were nearly uniform at each axial position in the nozzle. In the diverging section, PIV showed a transient, high-velocity central jet surrounded by large areas of recirculation and eddy formation. The single-phase experimental results, prior to cavitation onset, were supplemented by Computational Fluid Dynamics (CFD) simulations of the velocity distribution using Fluent software.