Development of a simulation tool for torsional vibration of branched power transmission system

In this master's thesis a mechanical model that is driven with variable speed synchronous machine was developed. The developed mechanical model simulates the mechanics of power transmission and its torsional vibrations. The mechanical model was developed for the need of the branched mechanics of a rolling mill and the propulsion system of a tanker. First, the scope of the thesis was to clarify the concepts connected to the mechanical model. The clarified concepts are the variable speed drive, the mechanics of power transmission and the vibrationsin the power transmission. Next, the mechanical model with straight shaft line and twelve moments of inertia that existed in the beginning was developed to be branched considering the case of parallel machines and the case of parallel rolls. Additionally, the model was expanded for the need of moreaccurate simulation to up to thirty moments of inertia. The model was also enhanced to enable three phase short circuit situation of the simulated machine. After that the mechanical model was validated by comparing the results of the developed simulation tool to results of other simulation tools. The compared results are the natural frequencies and mode shapes of torsional vibration, the response of the load torque step and the stress in the mechanical system occurred by the permutation of the magnetic field that is arisen from the three phase short circuit situation. The comparisons were accomplished well and the mechanical model was validated for the compared cases. Further development to be made is to develop the load torque to be time-dependent and to install two frequency converters and two FEM modeled machines to be simulated parallel.

Moment Operators of Observables in Quantum Mechanics, with Applications to Quantization and Homodyne Detection

The questions studied in this thesis are centered around the moment operators of a quantum observable, the latter being represented by a normalized positive operator measure. The moment operators of an observable are physically relevant, in the sense that these operators give, as averages, the moments of the outcome statistics for the measurement of the observable. The main questions under consideration in this work arise from the fact that, unlike a projection valued observable of the von Neumann formulation, a general positive operator measure cannot be characterized by its first moment operator. The possibility of characterizing certain observables by also involving higher moment operators is investigated and utilized in three different cases: a characterization of projection valued measures among all the observables is given, a quantization scheme for unbounded classical variables using translation covariant phase space operator measures is presented, and, finally, a mathematically rigorous description is obtained for the measurements of rotated quadratures and phase space observables via the high amplitude limit in the balanced homodyne and eight-port homodyne detectors, respectively. In addition, the structure of the covariant phase space operator measures, which is essential for the above quantization, is analyzed in detail in the context of a (not necessarily unimodular) locally compact group as the phase space.

Use of Biomass Gasification for Transport

This thesis represents an overview of biomass gasification technology together with some practical aspects of this technology application for transport in Finland. The main aim of this work is an assessment whether this technology is perspective in the nearest future for the wide use on transport or not. The first part of the thesis is a kind of survey of the previous works and materials con-cerning the usage of biomass gasification for transport. The second part concentrates more on the practical moments of its use for mobile applications in Finland (taxation, emissions, etc.).

Puunkäsittelykoneen simulointi ja mekaaniset häviöt

Diplomityö on osa Savonia-amk:n koneosaston TOVI-projektia, jossa metsä-konevalmistaja Ponsse Oyj on mukana. Työssä tutkittiin Ponsse Oyj:n metsäkoneen harvesteripäätä. Tavoitteena oli harvesteripään puun syöttöliikkeessä syntyvien mekaanisten häviöiden selvittäminen. Mekaanisilla häviöillä tarkoitamme karsintaterien kitkavoimia ja syöttörullien vierintävastusta.Edellisten lisäksi tavoitteena oli tutkia puun syöttöliikkeen simuloitavuutta monikappaledynamiikkaan perustuvalla simu-lointiohjelmistolla. Työ toteutettiin mittaamalla harvesteripään hydraulisten toimilaitteiden paineita, puun syötön aikana. Mittasimme myös puun ja harvesteripään välistä liikematkaa, nopeutta, kiihtyvyyttä, sekä puun paksuutta. Mittausten lisäksi harvesteripäästä rakennettiin simulointimalli. Mitattujen paineiden avulla laskettiin vastaavien toimilaitteiden synnyttämät voimat ja momentit. Simulointimallilla toistettiin mittaustapahtumat, käyttäen mittausten avulla laskettuja voimia ja momentteja. Mallin kitkakertoimien ja vierintävastusten avulla simuloidut ja mitatut liikematkat haettiin yhteneviksi. Toisin sanoen, simulointimalli verifioitiin todellisuutta vastaavaksi, jolloin simulointimallista voitiin lukea syntyneet häviöt.

Direct-on-line axial flux permanent magnet synchronous generator static and dynamic performance

In distributed energy production, permanent magnet synchronous generators (PMSG) are often connected to the grid via frequency converters, such as voltage source line converters. The price of the converter may constitute a large part of the costs of a generating set. Some of the permanent magnet synchronous generators with converters and traditional separately excited synchronous generators couldbe replaced by direct-on-line (DOL) non-controlled PMSGs. Small directly networkconnected generators are likely to have large markets in the area of distributed electric energy generation. Typical prime movers could be windmills, watermills and internal combustion engines. DOL PMSGs could also be applied in island networks, such as ships and oil platforms. Also various back-up power generating systems could be carried out with DOL PMSGs. The benefits would be a lower priceof the generating set and the robustness and easy use of the system. The performance of DOL PMSGs is analyzed. The electricity distribution companies have regulations that constrain the design of the generators being connected to the grid. The general guidelines and recommendations are applied in the analysis. By analyzing the results produced by the simulation model for the permanent magnet machine, the guidelines for efficient damper winding parameters for DOL PMSGs are presented. The simulation model is used to simulate grid connections and load transients. The damper winding parameters are calculated by the finite element method (FEM) and determined from experimental measurements. Three-dimensional finite element analysis (3D FEA) is carried out. The results from the simulation model and 3D FEA are compared with practical measurements from two prototype axial flux permanent magnet generators provided with damper windings. The dimensioning of the damper winding parameters is case specific. The damper winding should be dimensioned based on the moment of inertia of the generating set. It is shown that the damper winding has optimal values to reach synchronous operation in the shortest period of time after transient operation. With optimal dimensioning, interferenceon the grid is minimized.

Moottoriajoneuvon suorituskyvyn mittausjärjestelmä

Työn tarkoituksena oli toteuttaa moottoriajoneuvon suorituskyvyn mittaukseen käytettävä järjestelmä. Järjestelmä koostuu sylinterin muotoisesta rullasta ja tiedonkeruujärjestelmästä. Rullaa, jonka hitausmomentti tunnetaan kiihdytetään ajoneuvon vetopyörien välityksellä ja mitatuista arvoista lasketaan teho ja vääntömomenttiarvot moottorin kierrosluvun funktiona. Tiedonkeruu tapahtuu PC-mikrotietokoneen avulla, johon on liitetty tiedonkeruukortti. PC-mikrotietokone muodostaa käyttöliittymän, jonka avulla saadut tulokset esitetään kuvaajien avulla käyttäjälle. Käyttöliittymän avulla suoritetaan myös tulosten talletus ja raportin tulostus. Teoriaosassa tarkastellaan suorituskyvyn mittaamiseen käytettyjä menetelmiä ja laitteistoja, sekä tiedonkeruujärjestelmän rakennetta ja sen valintaan vaikuttavia tekijöitä. Käytännön osassa suunnitellaan muokkainkortti, jonka avulla erilaisilta antureilta saadut signaalit voidaan sovittaa tiedonkeruukortin tuloalueelle sopiviksi. Myös käyttöliittymän toimintaa ja sen rakentamiseen käytettyjä työkaluja tarkastellaan.

Resa i röstens landskap : en narrativ studie av hur lärare blir professionella röstanvändare

The theme of this thesis is the learning process that occurs when teachers become professional voice users. The aim is to explore what it (really) means to become a professional voice user in a teaching profession; thereby developing an understanding of how future education in this field can be arranged so as to both effectively prevent vocal problems and to develop oral didactical competence among teachers. The ambition is to describe, interpret, and understand the learning process through a combination of emic and ethic research perspectives. The theoretical frame of reference reflects the cross disciplinary character of the thesis. Voice problems are common among both student teachers and inservice teachers and adversely affect professional competence, identity and quality of life. Additionally, vocal problems are proven to have a negative impact on pupils´ learning. The individual elements of learning are explored in the light of experiential learning theory and transformative learning theory. The social elements of learning are explored in relation to the theory of situated learning. In addition, theories of teacher professionalisation in terms of competence and identity are outlined. The empirical study has a longitudinal and multi method character. It is anchored in a phenomenological hermeneutical tradition, more specifically in narrative inquiry. The point of departure is the learning experiences of ten student teachers, who attended a ten week long course on voice production as part of their teacher training at Åbo Akademi University, in the autumn of 2002 and the spring of 2003. Four interviews in the form of conversations were conducted with each participant. These were crystallised with a process diary, a Swedish Voice Handicap Index, a voice observation, and a video observation. A fifth interview was conducted with each participant five years post teacher training, in the spring of 2008. Participant observation was also conducted throughout the course. The research materials have been analysed and interpreted narratively using a phenomenological hermeneutical method. The results are presented descriptively as individual narratives, which are reflected in logopedic research materials. Learning is here understood as emergent awareness. This is followed by a meta narrative concerning learning as experiences in the four dimensions body, thought, feeling, and relation. Finally, interpretation is expressed with respect to the theory of relational education. Learning is here understood as a movement in the field between the actual and the possible voice. It is also viewed as fundamentally rooted in inter-human relationships, in moments of presence and coexistence. As a tentative answer to the call for an existential space for learning in order to be a professional voice user, I suggest the concept of a learning refuge as a locus for a learning process built on trust, mutuality and openness.