Unca Don and Unca Scrooge’s Guide to History. Representations of the Past in the Disney Comics of Don Rosa

This thesis studies the various forms and layers of representations of the past that can be found in the Disney comics of Don Rosa. To stay true to the legacy of renowned comic book artist Carl Barks, Rosa has stopped time in the duck universe to the 1950’s: the decade when Barks created his most noted stories. There is a special feel of historicalness in Rosa’s duck stories, as his characters recall events that occurred in both Rosa’s own stories as well as Barks’. Rosa has shed new light to the past of the characters by writing and illustrating the history of Scrooge McDuck, one of the most beloved Disney characters. Rosa is also adamant that the historical facts used in his stories are always correct and based on thorough research. The methodological tools used in the analysis of the comics come from the fields of comic book studies, film theory, and history culture. Film and comics are recognized by many scholars as very similar media, which share elements that make them comparable in many ways. This thesis utilizes studies on historical film, narrative and genre, which provide valuable insight and comparisons for analysis. The thesis consists of three main chapters, the first of which deconstructs the duck universe in the stories in order to understand how the historicalness in them is created,and which outside elements might affect them, including the genre of Disney comics, publishers, and the legacy of Barks. The next chapter focuses on The Life and Times of Scrooge McDuck series, i.e. the stories which are located in the past. Such stories feature similar representations of history as for example Westerns. They also compress and alter history to meet the restrictions of the medium of comics. The last part focuses on the adventure stories which draw inspiration from for example mythology, and take the characters to strange and mystical, but yet historical worlds. Such treasure-hunting stories show similarity to the action-adventure genre in film and for example their stereotypical representations of foreign cultures. Finally, the chapter addresses the problematic of historical fiction and its capability to write history.

Conventional and novel cardiovascular risk factors in young Finns and their associations with structural and functional vascular changes of subclinical atherosclerosis. The Cardiovascular Risk in Young Finns Study

Background: Atherosclerosis begins in early life progressing from asymptomatic to symptomatic as we age. Although substantial progress has been made in identifying the determinants of atherosclerosis in middle to older age adults at increased cardiovascular risk, there is lack of data examining determinants and prediction of atherosclerosis in young adults. Aims: The current study was designed to investigate levels of cardiovascular risk factors in young adults, subclinical measures of atherosclerosis, and prediction of subclinical arterial changes with conventional risk factor measures and novel metabolic profiling of serum samples. Subjects and Methods: This thesis utilised data from the follow-ups performed in 2001 and 2007 in the Cardiovascular Risk in Young Finns study, a Finnish population-based prospective cohort study that examined 2,204 subjects who were aged 30-45 years in 2007. Subclinical atherosclerosis was studied using noninvasive ultrasound measurements of carotid intima-media thickness (IMT), carotid arterial distensibility (CDist) and brachial flow-mediated dilation (FMD). Measurements included conventional risk factors and metabolic profiling using highthroughput nuclear magnetic resonance (NMR) methods that provided data on 42 lipid markers and 16 circulating metabolites. Results: Trends in lipids were favourable between 2001 and 2007, whereas waist circumference, fasting glucose, and blood pressure levels increased. To study the stability of noninvasive ultrasound markers, 6-year tracking (the likelihood to maintain the original fractile over time) in 6 years was examined. IMT tracked more strongly than CDist and FMD. Cardiovascular risk scores (Framingham, SCORE, Finrisk, Reynolds and PROCAM) predicted subclinical atherosclerosis equally. Lipoprotein subclass testing did not improve the prediction of subclinical atherosclerosis over and above conventional risk factors. However, circulating metabolites improved risk stratification. Tyrosine and docosahexaenoic acid were found to be novel biomarkers of high IMT. Conclusions: Prediction of cardiovascular risk in young Finnish adults can be performed with any of the existing risk scores. The addition of metabonomics to risk stratification improves prediction of subclinical changes and enables more accurate targeting of prevention at an early stage.

Frequency-Domain and Wide-Pulse Time-Domain Measurements of Lanthanide Luminescence and Lanthanide-Based Resonance Energy Transfer

Resonance energy transfer (RET) is a non-radiative transfer of the excitation energy from the initially excited luminescent donor to an acceptor. The requirements for the resonance energy transfer are: i) the spectral overlap between the donor emission spectrum and the acceptor absorption spectrum, ii) the close proximity of the donor and the acceptor, and iii) the suitable relative orientations of the donor emission and the acceptor absorption transition dipoles. As a result of the RET process the donor luminescence intensity and the donor lifetime are decreased. If the acceptor is luminescent, a sensitized acceptor emission appears. The rate of RET depends strongly on the donor–acceptor distance (r) and is inversely proportional to r6. The distance dependence of RET is utilized in binding assays. The proximity requirement and the selective detection of the RET-modified emission signal allow homogeneous separation free assays. The term lanthanide-based RET is used when luminescent lanthanide compounds are used as donors. The long luminescence lifetimes, the large Stokes’ shifts and the intense, sharply-spiked emission spectra of the lanthanide donors offer advantages over the conventional organic donor molecules. Both the organic lanthanide chelates and the inorganic up-converting phosphor (UCP) particles have been used as donor labels in the RET based binding assays. In the present work lanthanide luminescence and lanthanide-based resonance energy transfer phenomena were studied. Luminescence lifetime measurements had an essential role in the research. Modular frequency-domain and time-domain luminometers were assembled and used successfully in the lifetime measurements. The frequency-domain luminometer operated in the low frequency domain ( 100 kHz) and utilized a novel dual-phase lock-in detection of the luminescence. One of the studied phenomena was the recently discovered non-overlapping fluorescence resonance energy transfer (nFRET). The studied properties were the distance and temperature dependences of nFRET. The distance dependence was found to deviate from the Förster theory and a clear temperature dependence was observed whereas conventional RET was completely independent of the temperature. Based on the experimental results two thermally activated mechanisms were proposed for the nFRET process. The work with the UCP particles involved the measurement of the luminescence properties of the UCP particles synthesized in our laboratory. The goal of the UCP particle research is to develop UCP donor labels for binding assays. In the present work the effect of the dopant concentrations and the core–shell structure on the total up-conversion luminescence intensity, the red–green emission ratio, and the luminescence lifetime was studied. Also the non-radiative nature of the energy transfer from the UCP particle donors to organic acceptors was demonstrated for the first time in aqueous environment and with a controlled donor–acceptor distance.

Episodes in carbohydrate chemistry : from β-linked mannosides to glycoconjugates

Carbohydrates are one of the most abundant classes of biomolecules on earth. In the initial stages of research on carbohydrates much effort was focused on investigation and determination of the structural aspects and complex nature of individual monosaccharides. Later on, development of protective group strategies and methods for oligosaccharide synthesis became the main topics of research. Today, the methodologies developed early on are being utilized in the production of carbohydrates for biological screening events. This multidisciplinary approach has generated the new discipline of glycobiology which focuses on research related to the appearance and biological significance of carbohydrates. In more detail, studies in glycobiology have revealed the essential roles of carbohydrates in cell-cell interactions, biological recognition events, protein folding, cell growth and tumor cell metastasis. As a result of these studies, carbohydrate derived diagnostic and therapeutic agents are likely to be of growing interest in the future. In this doctoral thesis, a journey through the fundamentals of carbohydrate synthesis is presented. The research conducted on this journey was neither limited to the study of any particular phenomena nor to the addressing of a single synthetic challenge. Instead, the focus was deliberately shifted from time to time in order to broaden the scope of the thesis, to continue the learning process and to explore new areas of carbohydrate research. Throughout the work, several previously reported synthetic protocols, especially procedures related to glycosylation reactions and protective group manipulations, were evaluated, modified and utilized or rejected. The synthetic molecules targeted within this thesis were either required for biological evaluations or utilized to study phenomena occuring in larger molecules. In addition, much effort was invested in the complete structural characterization of the synthesized compounds by a combination of NMR spectroscopic techniques and spectral simulations with the PERCH-software. This thesis provides the basics of working with carbohydrate chemistry. In more detail, synthetic strategies and experimental procedures for many different reactions and guidelines for the NMR-spectroscopic characterization of oligosaccharides and glycoconjugates are provided. Therefore, the thesis should prove valuable to researchers starting their own journeys in the ever expanding field of carbohydrate chemistry.

Synthesis of percarboxylic acids in microreactor

Percarboxylic acids are commonly used as disinfection and bleaching agents in textile, paper, and fine chemical industries. All of these applications are based on the oxidative potential of these compounds. In spite of high interest in these chemicals, they are unstable and explosive chemicals, which increase the risk of synthesis processes and transportation. Therefore, the safety criteria in the production process should be considered. Microreactors represent a technology that efficiently utilizes safety advantages resulting from small scale. Therefore, microreactor technology was used in the synthesis of peracetic acid and performic acid. These percarboxylic acids were produced at different temperatures, residence times and catalyst i.e. sulfuric acid concentrations. Both synthesis reactions seemed to be rather fast because with performic acid equilibrium was reached in 4 min at 313 K and with peracetic acid in 10 min at 343 K. In addition, the experimental results were used to study the kinetics of the formation of performic acid and peracetic acid. The advantages of the microreactors in this study were the efficient temperature control even in very exothermic reaction and good mixing due to the short diffusion distances. Therefore, reaction rates were determined with high accuracy. Three different models were considered in order to estimate the kinetic parameters such as reaction rate constants and activation energies. From these three models, the laminar flow model with radial velocity distribution gave most precise parameters. However, sulfuric acid creates many drawbacks in this synthesis process. Therefore, a ´´greener´´ way to use heterogeneous catalyst in the synthesis of performic acid in microreactor was studied. The cation exchange resin, Dowex 50 Wx8, presented very high activity and a long life time in this reaction. In the presence of this catalyst, the equilibrium was reached in 120 second at 313 K which indicates a rather fast reaction. In addition, the safety advantages of microreactors were investigated in this study. Four different conventional methods were used. Production of peracetic acid was used as a test case, and the safety of one conventional batch process was compared with an on-site continuous microprocess. It was found that the conventional methods for the analysis of process safety might not be reliable and adequate for radically novel technology, such as microreactors. This is understandable because the conventional methods are partly based on experience, which is very limited in connection with totally novel technology. Therefore, one checklist-based method was developed to study the safety of intensified and novel processes at the early stage of process development. The checklist was formulated using the concept of layers of protection for a chemical process. The traditional and three intensified processes of hydrogen peroxide synthesis were selected as test cases. With these real cases, it was shown that several positive and negative effects on safety can be detected in process intensification. The general claim that safety is always improved by process intensification was questioned.

Understanding the in vitro dissolution rate of glasses with respect to future clinical applications

Glass is a unique material with a long history. Several glass products are used daily in our everyday life, often unnoticed. Glass can be found not only in obvious applications such as tableware, windows, and light bulbs, but also in tennis rackets, windmill turbine blades, optical devices, and medical implants. The glasses used at present as implants are inorganic silica-based melt-derived compositions mainly for hard-tissue repair as bone graft substitute in dentistry and orthopedics. The degree of glass reactivity desired varies according to implantation situation and it is vital that the ion release from any glasses used in medical applications is controlled. Understanding the in vitro dissolution rate of glasses provides a first approximation of their behavior in vivo. Specific studies concerning dissolution properties of bioactive glasses have been relatively scarce and mostly concentrated to static condition studies. The motivation behind this work was to develop a simple and accurate method for quantifying the in vitro dissolution rate of highly different types of glass compositions with interest for future clinical applications. By combining information from various experimental conditions, a better knowledge of glass dissolution and the suitability of different glasses for different medical applications can be obtained. Thus, two traditional and one novel approach were utilized in this thesis to study glass dissolution. The chemical durability of silicate glasses was tested in water and TRIS-buffered solution at static and dynamic conditions. The traditional in vitro testing with a TRISbuffered solution under static conditions works well with bioactive or with readily dissolving glasses, and it is easy to follow the ion dissolution reactions. However, in the buffered solution no marked differences between the more durable glasses were observed. The hydrolytic resistance of the glasses was studied using the standard procedure ISO 719. The relative scale given by the standard failed to provide any relevant information when bioactive glasses were studied. However, the clear differences in the hydrolytic resistance values imply that the method could be used as a rapid test to get an overall idea of the biodegradability of glasses. The standard method combined with the ion concentration and pH measurements gives a better estimate of the hydrolytic resistance because of the high silicon amount released from a glass. A sensitive on-line analysis method utilizing inductively coupled plasma optical emission spectrometer and a flow-through micro-volume pH electrode was developed to study the initial dissolution of biocompatible glasses. This approach was found suitable for compositions within a large range of chemical durability. With this approach, the initial dissolution of all ions could be measured simultaneously and quantitatively, which gave a good overall idea of the initial dissolution rates for the individual ions and the dissolution mechanism. These types of results with glass dissolution were presented for the first time during the course of writing this thesis. Based on the initial dissolution patterns obtained with the novel approach using TRIS, the experimental glasses could be divided into four distinct categories. The initial dissolution patterns of glasses correlated well with the anticipated bioactivity. Moreover, the normalized surface-specific mass loss rates and the different in vivo models and the actual in vivo data correlated well. The results suggest that this type of approach can be used for prescreening the suitability of novel glass compositions for future clinical applications. Furthermore, the results shed light on the possible bioactivity of glasses. An additional goal in this thesis was to gain insight into the phase changes occurring during various heat treatments of glasses with three selected compositions. Engineering-type T-T-T curves for glasses 1-98 and 13-93 were stablished. The information gained is essential in manufacturing amorphous porous implants or for drawing of continuous fibers of the glasses. Although both glasses can be hot worked to amorphous products at carefully controlled conditions, 1-98 showed one magnitude greater nucleation and crystal growth rate than 13-93. Thus, 13-93 is better suited than 1-98 for working processes which require long residence times at high temperatures. It was also shown that amorphous and partially crystalline porous implants can be sintered from bioactive glass S53P4. Surface crystallization of S53P4, forming Na2O∙CaO∙2SiO2, was observed to start at 650°C. The secondary crystals of Na2Ca4(PO4)2SiO4, reported for the first time in this thesis, were detected at higher temperatures, from 850°C to 1000°C. The crystal phases formed affected the dissolution behavior of the implants in simulated body fluid. This study opens up new possibilities for using S53P4 to manufacture various structures, while tailoring their bioactivity by controlling the proportions of the different phases. The results obtained in this thesis give valuable additional information and tools to the state of the art for designing glasses with respect to future clinical applications. With the knowledge gained we can identify different dissolution patters and use this information to improve the tuning of glass compositions. In addition, the novel online analysis approach provides an excellent opportunity to further enhance our knowledge of glass behavior in simulated body conditions.

Coercion, Perceived Care and Quality of Life Among Patients in Psychiatric Hospitals

The goals of the study were to describe patients’ perceptions of care after experiencing seclusion/restraint and their quality of life. The goal was moreover to identify methodological challenges related to studies from the perspective of coerced patients. The study was conducted in three phases between September 2008 and April 2012. In the first phase, the instrument Secluded/ Restrained Patients’ Perception of their Treatment (SR-PPT) was developed and validated in Japan in cooperation with a Finnish research group (n = 56). Additional data were collected over one year from secluded/restrained patients using the instrument (n = 90). In the second phase, data were collected during the discharge process (n = 264). In the third phase, data were collected from electronic databases. Methodological and ethical issues were reviewed (n = 32) using systematic review method. Patients perceived that co-operation with the staff was poor; patients’ opinions were not taken into account, treatment targets collated and treatment methods were seen in different ways. Patients also felt that their concerns were not well enough understood. However, patients received getting nurses’ time. In particular, seclusion/restraint was considered unnecessary. The patients felt that they benefited from the isolation in treating their problems more than they needed it, even if the benefit was seen to be minor. Patients treated on forensic wards rated their treatment and care significantly lower than in general units. During hospitalization secluded/restrained patients evaluated their quality of life, however, better than did non-secluded/restrained patients. However, no conclusion is drawn to the effect that the better quality of life assessment is attributable to the seclusion/restraint because patients’ treatment period after the isolation was long and because of many other factors, as rehabilitation, medication, diagnostic differences, and adaptation. According to the systematic mixed studies review variation between study designs was found to be a methodological challenge. This makes comparison of the results more difficult. A research ethical weakness is conceded as regards descriptions of the ethical review process (44 %) and informed consent (32 %). It can be concluded that patients in psychiatric hospital care and having a voice as an equal expert require special attention to clinical nursing, decision-making and service planning. Patients and their family members will be consulted in plans of preventive and alternative methods for seclusion and restraint. The study supports the theory that in ethical decision-making situations account should be taken of medical indications, in addition to the patients’ preferences, the effect of treatment on quality of life, and this depends on other factors. The connection between treatment decisions and a patient’s quality of life should be evaluated more structurally in practice. Changing treatment culture towards patients’ involvement will support daily life in nursing and service planning taking into account improvements in patients’ quality of life.

„Und frei erklär' ich alle meine Knechte“ : Höflichkeit als Ausdruck sozialer Utopie in Schillers Drama Wilhelm Tell.

My dissertation is an interdisciplinary study of the relationship between the Swiss peasants and nobles in Friedrich Schiller’s play Wilhelm Tell (1804). Changes to this relationship are of particular interest. Communication in the play is examined via a micro-analysis based on Penelope Brown’s and Stephen C. Levinson’s theoretical framework Politeness: Some universals in language usage. (1978, 1987). Brown and Levinson distinguish between positivepoliteness and negative-politeness strategies and their distinction is useful for my argument, since they claim that the use of positive-politeness strategies reflects the speaker’s intention to minimize the distance between the interlocutors (Brown and Levinson 1987: 103). Negative-politeness strategies, by contrast, result in social distancing (Brown and Levinson 1987: 130). In accordance with Brown’s and Levinson’s theory, it can be argued that the distribution of positive-politeness and negative-politeness strategies reflects changes in the distance between the fictional interlocutors as representatives of their social classes in Wilhelm Tell. The analysis of the communication in the play highlights that existing conflicts within the social groups are resolved and replaced with solidarity (cf. ‘Claim ’common ground’ and ‘Claim in-group membership with H’) before the peasants and noblemen appear on stage simultaneously in III, 3. In the scene in question, Geßler forces Tell to shoot the apple off his son’s head. Although both nobles and peasants are present, they do not communicate with each other. Thus, communication between the social classes occurs for the first time in IV, 2. This scene is crucial with regard to the changes in the relationship between the social classes in the play. The younger generation, with Rudenz as a representative of the nobility and Melchthal as a representative of the peasants, break with the prevailing conventions and initiate a new type of cooperation based on mutual helping and equality in the right and the duty to protect the country from the violent oppressors representing Habsburg (cf. ‘Convey that S and H are cooperators’, ‘Claim reflexivity’ and ‘Claim reciprocity’). The linguistic analysis reveals the crucial role of the Swiss nobility in the development of the social utopia, as well as the non-contribution of Wilhelm Tell. In fact, Tell never communicates with the Swiss noblemen. The role of the nobility and the role of Wilhelm Tell are further investigated in a comparison between Schiller’s Wilhelm Tell and four of Schiller’s historical sources. These sources, which contain earlier, non-dramatic versions of the establishment of the Swiss Confederation, are the following: Kronica von der loblichen Eydtgnoschaft compiled by Petermann Etterlin (1507), Gemeiner loblicher Eydgnoschafft Stetten Landen vnd Völckeren Chronik wirdiger thaaten beschreybung (1548) written by Johann Stumpf, Chronicon Helveticum of Aegidius Tschudi (the publication of Iselin from 1734 and 1736) and Johannes von Müller’s Geschichten schweizerischer Eidgenossenschaft (1786). Thecomparison sheds light on the fact that both Tschudi and von Müller emphasize unity among the Swiss and cooperation in their attempt to defeat the enemy. However, Schiller has reinforced the role of the nobility in the cooperation. In addition, the comparison between Schiller’s play and the historical sources reveals profound differences with regard to the role of Wilhelm Tell. In all of Schiller’s sources, Tell is present at Rütli, whereas he is absent from Rütli in Schiller’s play. In the play in general, Tell is conspicuously separated from the other peasants. Explanations of my linguistic results, which correspond to the above mentioned differences between the roles of the figures in Wilhelm Tell and the depictions in Schiller’s sources, are found by comparing the path of Schiller’s Swiss towards an egalitarian perspective with the kind of social evolution depicted by the German philosopher Johann Benjamin Erhard in his essay Über das Recht des Volks zu einer Revolution (1795). Aiming at considering Schiller’s social utopia within the larger cultural framework of the German response to the French Revolution, the comparison suggests that both authors depict the need for social change in terms of a change in social hierarchies (Erhard 1970: 95-96, cf. Foi 2005: 225). Erhard’s essay thus helps explain the political intention of Schiller’s play to keep the ideals of the French Revolution as crucial aims but profoundly change the means towards freedom and equality. In his attempt to claim the political resistance of the nobles and peasants as just, however, Schiller sacrificed the figure of Wilhelm Tell. Guilty of the murder of Geßler, Tell was no longer suitable for the righteous revolution imagined by Schiller (cf. Bloch 2008: 215 and Schulz 2005: 228). This explains Tell’s absence in the Rütli scene, his isolation in the plot, as well as his non-contribution to the social utopia. Together, the linguistic analysis and contextualisation of Schiller’s play support my hypothesis that Wilhelm Tell describes a process of change in the relationship between peasants and nobles. The interdisciplinary approach to the topic proved to be fruitful for all areas of the research involved.

Power semiconductor nonlinearities in active du/dt output filtering

This doctoral thesis introduces an improved control principle for active du/dt output filtering in variable-speed AC drives, together with performance comparisons with previous filtering methods. The effects of power semiconductor nonlinearities on the output filtering performance are investigated. The nonlinearities include the timing deviation and the voltage pulse waveform distortion in the variable-speed AC drive output bridge. Active du/dt output filtering (ADUDT) is a method to mitigate motor overvoltages in variable-speed AC drives with long motor cables. It is a quite recent addition to the du/dt reduction methods available. This thesis improves on the existing control method for the filter, and concentrates on the lowvoltage (below 1 kV AC) two-level voltage-source inverter implementation of the method. The ADUDT uses narrow voltage pulses having a duration in the order of a microsecond from an IGBT (insulated gate bipolar transistor) inverter to control the output voltage of a tuned LC filter circuit. The filter output voltage has thus increased slope transition times at the rising and falling edges, with an opportunity of no overshoot. The effect of the longer slope transition times is a reduction in the du/dt of the voltage fed to the motor cable. Lower du/dt values result in a reduction in the overvoltage effects on the motor terminals. Compared with traditional output filtering methods to accomplish this task, the active du/dt filtering provides lower inductance values and a smaller physical size of the filter itself. The filter circuit weight can also be reduced. However, the power semiconductor nonlinearities skew the filter control pulse pattern, resulting in control deviation. This deviation introduces unwanted overshoot and resonance in the filter. The controlmethod proposed in this thesis is able to directly compensate for the dead time-induced zero-current clamping (ZCC) effect in the pulse pattern. It gives more flexibility to the pattern structure, which could help in the timing deviation compensation design. Previous studies have shown that when a motor load current flows in the filter circuit and the inverter, the phase leg blanking times distort the voltage pulse sequence fed to the filter input. These blanking times are caused by excessively large dead time values between the IGBT control pulses. Moreover, the various switching timing distortions, present in realworld electronics when operating with a microsecond timescale, bring additional skew to the control. Left uncompensated, this results in distortion of the filter input voltage and a filter self-induced overvoltage in the form of an overshoot. This overshoot adds to the voltage appearing at the motor terminals, thus increasing the transient voltage amplitude at the motor. This doctoral thesis investigates the magnitude of such timing deviation effects. If the motor load current is left uncompensated in the control, the filter output voltage can overshoot up to double the input voltage amplitude. IGBT nonlinearities were observed to cause a smaller overshoot, in the order of 30%. This thesis introduces an improved ADUDT control method that is able to compensate for phase leg blanking times, giving flexibility to the pulse pattern structure and dead times. The control method is still sensitive to timing deviations, and their effect is investigated. A simple approach of using a fixed delay compensation value was tried in the test setup measurements. The ADUDT method with the new control algorithm was found to work in an actual motor drive application. Judging by the simulation results, with the delay compensation, the method should ultimately enable an output voltage performance and a du/dt reduction that are free from residual overshoot effects. The proposed control algorithm is not strictly required for successful ADUDT operation: It is possible to precalculate the pulse patterns by iteration and then for instance store them into a look-up table inside the control electronics. Rather, the newly developed control method is a mathematical tool for solving the ADUDT control pulses. It does not contain the timing deviation compensation (from the logic-level command to the phase leg output voltage), and as such is not able to remove the timing deviation effects that cause error and overshoot in the filter. When the timing deviation compensation has to be tuned-in in the control pattern, the precalculated iteration method could prove simpler and equally good (or even better) compared with the mathematical solution with a separate timing compensation module. One of the key findings in this thesis is the conclusion that the correctness of the pulse pattern structure, in the sense of ZCC and predicted pulse timings, cannot be separated from the timing deviations. The usefulness of the correctly calculated pattern is reduced by the voltage edge timing errors. The doctoral thesis provides an introductory background chapter on variable-speed AC drives and the problem of motor overvoltages and takes a look at traditional solutions for overvoltage mitigation. Previous results related to the active du/dt filtering are discussed. The basic operation principle and design of the filter have been studied previously. The effect of load current in the filter and the basic idea of compensation have been presented in the past. However, there was no direct way of including the dead time in the control (except for solving the pulse pattern manually by iteration), and the magnitude of nonlinearity effects had not been investigated. The enhanced control principle with the dead time handling capability and a case study of the test setup timing deviations are the main contributions of this doctoral thesis. The simulation and experimental setup results show that the proposed control method can be used in an actual drive. Loss measurements and a comparison of active du/dt output filtering with traditional output filtering methods are also presented in the work. Two different ADUDT filter designs are included, with ferrite core and air core inductors. Other filters included in the tests were a passive du/dtfilter and a passive sine filter. The loss measurements incorporated a silicon carbide diode-equipped IGBT module, and the results show lower losses with these new device technologies. The new control principle was measured in a 43 A load current motor drive system and was able to bring the filter output peak voltage from 980 V (the previous control principle) down to 680 V in a 540 V average DC link voltage variable-speed drive. A 200 m motor cable was used, and the filter losses for the active du/dt methods were 111W–126 W versus 184 W for the passive du/dt. In terms of inverter and filter losses, the active du/dt filtering method had a 1.82-fold increase in losses compared with an all-passive traditional du/dt output filter. The filter mass with the active du/dt method was 17% (2.4 kg, air-core inductors) compared with 14 kg of the passive du/dt method filter. Silicon carbide freewheeling diodes were found to reduce the inverter losses in the active du/dt filtering by 18% compared with the same IGBT module with silicon diodes. For a 200 m cable length, the average peak voltage at the motor terminals was 1050 V with no filter, 960 V for the all-passive du/dt filter, and 700 V for the active du/dt filtering applying the new control principle.