Wave energy converters (WECs) are relatively new power sources under rapiddevelopment. WECs utilize permanent magnets to generate power and theperformance of these magnets have a great impact on the produced effects in theWECs. This paper is primarily constructed to investigate the magnetic and mechanicalproperties of a specific kind of permanent magnets, referred to as Y40. The paperalso gives a comprehensive review of magnetic materials in general, slightly focusingon magnetic stability. Literature studies has been made to get an understanding ofhow the Y40 magnets will perform under external influences such as reversed field,temperature change and mechanical stress. Further, a compression test has beenmade to examine the Y40s solidity. From the results of the tests and from theinformation provided in literature it is considered to be little to no risk for the Y40sto lose magnetization due to external influences. However, because of theirassembled structure, the Y40 magnets are very likely to break in their joints duringpressure lower than what is expected in the WECs.

The task in this project is to design a generator for a vertical axis wind turbine withpower rated to 20kW at a wind speed of 10m/s. The project is conducted at theDivision of Electricity at Uppsala University with collaboration from ElectricGeneration AB. The design has just a few moving parts, which decreases maintenancecosts and increases its toughness. The turbine absorbs wind from every direction butits rotation speed ratio is lower than horizontal axis wind turbines. It means that thegenerator must be bigger and therefore more expensive. Price is an importantcriterion for the generator. Neodymium magnets are expensive so the amount of thismaterial must be limited.Several designs have been simulated but one final design has proven the mostpromising. It fulfills all specifications such as efficiency above 95%, 20kW outputpower and it also has a relatively low amount of hard magnetic material.A design with a single row of cables per slot was decided upon to eliminate heatpockets between cable rows, which can occur in designs with two cable rows perslot. It would be interesting to study designs with two or more cable rows per slot, asit could lead to a smaller and more efficient machine.

The thesis utilizes the analogy in dynamic equations between a mechanical and an electrical system to convert the steam-turbine, micro-turbine, wind-turbine and hydro-turbine generator mechanical model to equivalent electrical circuit models respectively. And based on the round rotor type and permanent magnetic rotor type synchronous generators¡¦ dynamic equations, as well as their electromagnetic torque equations, the equivalent electrical interface circuits were derived respectively. By using the interface circuit, the circuit model of synchronous generator and the equivalent electrical circuit model of turbine-generator mechanism can thus be combined into the electromechanical integrated circuit model (Thevenin¡¦s analogy circuit model and Norton's analogy circuit model). The electromechanical integrated circuit model is helpful for analyzing the energy conversion, power transmission and interactions between the mechanical and electrical systems for a turbine generator unit. In order to learn about these electromechanical interactions by using the proposed electromechanical integrated circuit model, the thesis has made a study on the torsional vibrations for a small gas turbine generator unit and for a large steam turbine generator unit respectively. By way of the frequency scanning and eigenvalue calculation, it is found that the torsional mode frequencies can be changed due to the electromechanical integration. Moreover, the small unit was more affected by the electromechanical integration than the large unit. Finally, we studied the effect of operations of an Electric Arc Furnaces (EAF) on torsional vibrations of a low capacity turbine generator. The electric system studied belongs to a practical steel plant in an industrial park. Based on the electromechanical integrated equivalent circuit model, a flywheel coupling shaft was designed. It is found by simulations that the coupling shaft can be quite effective in alleviating vibrations caused by the system unbalance arising from the EAF operations.

With the emergence of portable computing and communication systems, power consumption has become one of the major objectives during VLSI design. Furthermore, multipliers are always fundamental building blocks and the bottleneck in terms of power consumption in many DSP and multimedia applications. Therefore, it is crucial to minimize the power consumption of multipliers in the system for low-power VLSI design. Besides, energy-efficient multiplier is greatly desirable for DSP systems and computer architectures. In many of these systems, the dynamic-range of input operands for multiplier is usually very small. In addition, the least significant bits of output products are often rounded or truncated to avoid growth in word size. Based on these features, this thesis presents an approach to design low-power and reconfigurable signed pipelined multipliers. The approach dynamically detects input range of the multiplier and disables the switching operations of non-effective ranges to decrease the power consumption. Moreover, the proposed approach can reconfigure the output precision of the multiplier to save power consumption. We apply this approach to two architectures: array-based and Booth-based architecture. Experimental results show that the proposed array-based pipelined multiplier leads to up 47% power saving and Booth-based multiplier leads to up 30% power saving with a little additional area and delay overheads. Besides, in order to accord with the low cost and high profit-making goal of systematic products and shorten construction period, we have designed a low-power multiplier generator. User could use the user interface to configure the multiplier size, low power architecture and the precision that user need. The generator will create the hardware architecture of low-power multiplier automatically.

The Hayes Coastal Engineering Laboratory is a new laboratory with two water basins: a 45.72-meters long, 3.66 meters wide and 3.06 meters deep Tow Tank with sediment pit for dredging and current flow studies, and a 36.58 meters long, 22.86 meters wide and 1.22 meters deep 3D Wave Basin for coastal wave studies. In order to assess the capabilities of the lab a series of tests were done in both tanks. Hydrodynamic tests in the Tow Tank using a Micro Acoustic Doppler Velociometer measured current flow in the tank and assessed the efficacy of different filters to stabilize flow patterns. A concrete dam structure installed near the reversed diffusers most effectively stabilized flow of all the configurations tested. Wave tests were conducted in the 3D Wave Basin with the newly-installed 48 paddle Rexroth wave generator at 0.5 and 1.0 meter water depths using wired and wireless capacitance wave gauges. These tests measured characteristics of the generated waves and reflection from the rubble-mound beach. In addition, initial testing of the Active Reflection Absorber (ARA) system was done. Correlating the wave data to the theoretical wave being produced showed that with water depth of 0.5 meters the 0.1 meter waves were well-formed, but the 0.2 meter waves showed energy loss and lower correlation. The results from one meter water depth wave tests showed good formation of 0.2 meter waves. In nearly all wave tests with pool buoys installed the waves were better formed with good correlation and a better fitting power spectrum. The beach reflection was within the expected value range, being ten percent and below for most tests. ARA, while operational, needs to be further tuned to find the settings that will increase its effectiveness.

In this thesis , we studied the photo-chemistry between the green emitter (C545T) and the photo-acid generator (PAG) . When the sample of C545T and PAG in solutions and thin films were exposured to UV-light , we found that a new product was produced due to protonation of C545T with the acid generated by PAG . Therefore , we measured absorption and fluorescence spectra of the samples in solutions (THF) and in polymer (PMMA) thin films . The different concentrations of C545T dopanted photo-acid generator in the solvent (THF) could increase the photo-acid generator at higher concentrations of PAG , the energy could be transferred from unprotonated to protonated . Therefore , we can easily observe the absorption and fluorescence spectra have been changed and the phenomenon of stock¡¦s shift has been found accordingly . At higher concentrations of C545T in solutions , also called concentrations quenching effect was observed because C545T molecules could collide each other easily that causes intensity to decrease in the solvent (THF) . In order to get rid of the collision effect , we use the samples of polymer thin films instead of solutions . The different of the change of spectra between solutions and thin films were observed and compared were also studied .

Modeling and understanding the doses around the neutron generator provides insightful data in regard to radiation safety and protection precautions. Published data can be used to predict doses, but realistic data for the Nuclear Engineering Teaching Laboratory’s Thermo MP 320 Neutron Generator helps health physicists more accurately predict dose rates and protect experimenters against exposure. The goal was to create a model inclusive of the entire setup and room where the neutron generator is housed. Monte Carlo N-Particle (MCNP) Code reigns as the preferred method for modeling radiation transport and was utilized to model the transport of neutrons within the current configuration of the 14 MeV neutron generator facility. This model took into account all shielding materials and their respective dimensions and locations within the concrete room. By utilizing tallies and tally modifiers, the model predicts dose rates that can be used with experimental factors such as irradiation time and flux to predict a dose in millirem. Validation experiments were performed in the current setup using Landauer Luxel®+ with Neutrak dosimeters placed in strategic locations to record the neutron dose vi received as well as a Ludlum Model 42-41 PRESCILA neutron probe to predict dose rates. The dosimeters and PRESCILA measurement locations matched the positions of the point detector tallies in MCNP. After laboratory analysis, a comparison was performed between the model output and the dosimeter and PRESCILA values to successfully validate the accuracy of the model. / text

Jämtkraft AB has recently modernized its hydropower station at Hissmofors by replacing four older worn out units with two new units. The generators uses a concept with sliding stator feet to deal with the thermal movements that occur in the stator during operation when the unit is operating intermittently. At other sites, this method revealed shortcomings in the reliability. This has made Jämtkraft AB feel uncertainty about its function and therefore want to investigate it during an early stage.   The generators have a built-in monitoring system for the sliding stator feet and by using data from there the function of the sliding stator feet has been investigated. The study focused on how the different stator feet move relative to each other and how the eccentricity and deviation from roundness changed during operation.   The results show that there are several indications that the function of the sliding stator feet is not satisfactory. However, some results indicate well functioning stator feet.. The recommendation to Jämtkraft will therefore be to further investigated its performance by conducting a new roundness measurement and make new eccentricity calculations accordingly.

Zugl.: Furtwangen, Fachhochsch., Diplomarbeit, 1995

Zugl.: Zürich, Techn. Hochsch., Diss., 2008