This master's thesis deals with design and implementation of modular system for two-way loudspeaker system's characteristics. Work focus mainly on the enclosure geometry and speaker placement. The individual modules of the system were designed and then implemented. Furthermore, the characteristics of these modules were measured and laboratory tasks using these modules were elaborated.

The aim of this work is to create an automated workplace for measuring the basic parameters of audio amplifiers using a graphical programming environment LabVIEW. Subsequently, the functionality will be verified in practical measurements on the real amplifier.

This work deals with the design of a 10-zones equalizer with optimized frequency characteristics with a spectrum audio analyzer. In this work the problem of processing audio signals using equalization for filtering the interference frequencies, correction of frequency cover signal boost or suppression of the required zones of the audible spectrum are also analyzed. The influence of subjective perception of sound intensity of the audio signals reproduction and its use in working with equalizer is discussed too. The work describes the principles and usage of the audio-analyzer as a tool for the optimization of the audio equalization setting when ensuring the appropriate listening conditions of music reproduction, spoken word, sounds, etc. It also focuses on the signal source for testing audio-chains, their generation and measurement using the audio analyzer. The equalizer equipment, audio-analyzer generator of reference signals equipment and power supply are designed as a single unit.

This thesis deals with the calculation of response of reinforced concrete construction on the effect of seismic tension. Time and spectral analysis were made. They are mentioned as possible ways of calculation in EN 1998 - 1:2004 norm. Final figures of global deformations and stress on selected beam from the time and spectral analysis were firstly compared for the horizontal components of seismic stress affecting only in one direction. Subsequently comparison of time progress to combination of these effects mentioned in relevant norm was made. In the conclusion the results of used analysis are appraised.

This thesis is theoretically described heating surfaces, radiators and regulation valves. There are also described their features, advantages and disadvantages and division according to design. The aim of the work is determine the dynamics characteristics of heating surfaces and radiators including control valves, which are parts of measurement panel. Based on the measurement are determined appropriate characteristics of which are calculated values for regulating. The result of this study can serve as a guide to the practical measurement method of dynamics characteristics of the real-working heating systems, or serve as a template for the settings according to the measured data.

This thesis deals with the dynamic properties of electric pressure transducers. These are properties that are reflected in the measurement of rapid, time-dependent processes. They could be described in two ways. Either by using amplitude and phase frequency response characteristics, or just one particular value. Natural frequency, cutoff frequency or time constant. These parameters indicate the extreme values for the use of measuring devices in the measurement of time-dependent processes. In this work will be described procedures for determining these parameters.

Dizertačná práca rieši problematiku analýzy akustických vlastností pohonných jednotiek. V úvodnej časti je teoretický rozbor fyzikálnych princípov vibrácií a hluku a prehľad súčasného stavu riešenia problematiky v oblasti návrhu pohonných jednotiek. Vlastná časť práce popisuje konštrukčný návrh elektrodynamického budiča vibrácií, návrh hodnotenia výsledkov merania a taktiež spôsob spracovania výsledkov. Akustické vlastnosti sú hodnotené pomocou normálových rýchlostí kmitania povrchu. V závere práce sú prezentované ukážky využitia metódy v praktických príkladoch spojených s návrhom pohonnej jednotky. Celé riešenie predstavuje ucelený spôsob analýzy vhodný pre rýchle hodnotenie vplyvu konštrukčných úprav na akustické vlastnosti.

Cutting movement is still one of the main means to obtain the desired machined surface. As the most representative cutting method in subtractive manufacturing, milling is widely used in industrial production. However, the chatter induced by the dynamic interaction between machine tool and process not only reduces the accuracy of the machined workpiece, but also increases the tool wear and affects the rotary accuracy of the spindle. The stability lobe diagram can provide stable machining parameters for the technicians, and it is currently an effective way to avoid chatter. In fact, the dynamic interaction between the machine tool and process is very complicated, which involves the machine tool, milling tool, workpiece and fixture. The induced mechanism of chatter depends on different machining scenarios and is not entirely dependent on the vibration modes of milling tool. Therefore, it is important to obtain stable machining parameters and to know the dynamic surface location error distribution, which can ensure machining quality and improve machining efficiency. In this dissertation, two methods for constructing stability lobe diagram are first introduced, and then two machining scales, macro milling and micro milling, are studied. For the macro-milling scale, the dynamic response of the in-process workpiece with time-varying modal parameters during the material removal process is analyzed. The stability lobe diagrams for thin-walled workpiece and general workpiece with continuous radial immersion milling are established respectively. Besides, the cumulative surface location error distribution is also studied and verified for the general workpiece. For the micro-milling scale, the dynamics at the micro-milling tool point is obtained by means of the receptance coupling substructure analysis method. The stability lobe diagram and surface location error distribution are analyzed under different restricted/free tool overhang lengths. The relationship between measurement results and burrs is further explained by cutting experiments, and the difference between the two milling scales is compared in the end.

<p>When a design feature (such as material choice, internal bracing pattern, guitar body depth, and sound hole diameter) of an acoustic guitar changes, the effect of the change on the guitar’s sound is not well understood. As a result, luthiers approximate how to make guitars that have resonant frequencies of around 95-105 Hertz (Hz), the frequency range which sounds “good.” The researcher designed a reconfigurable fixture that simulated an acoustic guitar body with a variable body depth and sound hole diameter. The researcher used this testing fixture to examine the relationship between sound hole diameter, body depth, and resonant frequency. She conducted an experimental parameter sweep, measuring frequency response functions (FRFs) to collect data on the first, Helmholtz, and second resonant frequencies of the simulated acoustic guitar. The researcher pinpointed the general trends in the correlation between resonant frequency, body depth, and sound hole diameter using the frequency data from the FRF measurements. She determined that as sound hole diameter increased, the first, Helmholtz, and second resonant frequencies increased; and as body depth and body volume increased, the first and Helmholtz resonant frequencies decreased, while the second resonant frequency increased up until a body depth of approximately 4.50” inches. Exploring alternative design features and material choices contributes to improving urban infrastructure by encouraging luthiers to make instruments with sustainable materials (National Academy of Engineering, Grand Challenges – Restore and Improve Urban Infrastructure, 2023).</p>

Condition monitoring (CM) is widely used in industry, and there is a growing interest in applying CM on rail vehicle systems. Condition based maintenance has the possibility to increase system safety and availability while at the sametime reduce the total maintenance costs.This thesis investigates the feasibility of using condition monitoring of suspension element components, in this case dampers, in rail vehicles. There are different methods utilized to detect degradations, ranging from mathematicalmodelling of the system to pure "knowledge-based" methods, using only large amount of data to detect patterns on a larger scale. In this thesis the latter approach is explored, where acceleration signals are evaluated on severalplaces on the axleboxes, bogieframes and the carbody of a rail vehicle simulation model. These signals are picked close to the dampers that are monitored in this study, and frequency response functions (FRF) are computed between axleboxes and bogieframes as well as between bogieframes and carbody. The idea is that the FRF will change as the condition of the dampers change, and thus act as indicators of faults. The FRF are then fed to different classificationalgorithms, that are trained and tested to distinguish between the different damper faults.This thesis further investigates which classification algorithm shows promising results for the problem, and which algorithm performs best in terms of classification accuracy as well as two other measures. Another aspect explored is thepossibility to apply dimensionality reduction to the extracted indicators (features). This thesis is also looking into how the three performance measures used are affected by typical varying operational conditions for a rail vehicle,such as varying excitation and carbody mass. The Linear Support Vector Machine classifier using the whole feature space, and the Linear Discriminant Analysis classifier combined with Principal Component Analysis dimensionality reduction on the feature space both show promising results for the taskof correctly classifying upcoming damper degradations. / Tillståndsövervakning används brett inom industrin och det finns ett ökat intresse för att applicera tillståndsövervakning inom spårfordons olika system. Tillståndsbaserat underhåll kan potentiellt öka ett systems säkerhet och tillgänglighetsamtidigt som det kan minska de totala underhållskostnaderna.Detta examensarbete undersöker möjligheten att applicera tillståndsövervakning av komponenter i fjädringssystem, i detta fall dämpare, hos spårfordon. Det finns olika metoder för att upptäcka försämringar i komponenternas skick, från matematisk modellering av systemet till mer ”kunskaps-baserade” metodersom endast använder stora mängder data för att upptäcka mönster i en större skala. I detta arbete utforskas den sistnämnda metoden, där accelerationssignaler inhämtas från axelboxar, boggieramar samt vagnskorg från en simuleringsmodellav ett spårfordon. Dessa signaler är extraherade nära de dämpare som övervakas, och används för att beräkna frekvenssvarsfunktioner mellan axelboxar och boggieramar, samt mellan boggieramar och vagnskorg. Tanken är att frekvenssvarsfunktionerna förändras när dämparnas skick förändras ochpå så sätt fungera som indikatorer av dämparnas skick. Frekvenssvarsfunktionerna används sedan för att träna och testa olika klassificeringsalgoritmer för att kunna urskilja olika dämparfel.Detta arbete undersöker vidare vilka klassificeringsalgoritmer som visar lovande resultat för detta problem, och vilka av dessa som presterar bäst med avseende på noggrannheten i prediktionerna, samt två andra mått på algoritmernasprestanda. En annan aspekt som undersöks är möjligheten att applicera dimensionalitetsminskning på de extraherade indikatorerna. Detta arbete undersöker också hur de tre prestandamåtten som används påverkas av typiska förändringar i driftsförhållanden för ett spårfordon såsom varierande exciteringfrån spåret och vagnkorgsmassa. Resultaten visar lovande prestanda för klassificeringsalgoritmen ”Linear Support Vector Machine” som använder hela rymden med felindikatorer, samt algoritmen ”Linear Discriminant Analysis” i kombination med ”Principal Component Analysis” dimensionalitetsreducering.