A comparative performance study of four-pole induction motors and synchronous reluctance motors in variable speed drives

Design aspects of the Transversally Laminated Anisotropic (TLA) Synchronous Reluctance Motor (SynRM) are studied and the machine performance analysis compared to the Induction Motor (IM) is done. The SynRM rotor structure is designed and manufactured for a30 kW, four-pole, three-phase squirrel cage induction motor stator. Both the IMand SynRM were supplied by a sensorless Direct Torque Controlled (DTC) variablespeed drive. Attention is also paid to the estimation of the power range where the SynRM may compete successfully with a same size induction motor. A technicalloss reduction comparison between the IM and SynRM in variable speed drives is done. The Finite Element Method (FEM) is used to analyse the number, location and width of flux barriers used in a multiple segment rotor. It is sought for a high saliency ratio and a high torque of the motor. It is given a comparison between different FEM calculations to analyse SynRM performance. The possibility to take into account the effect of iron losses with FEM is studied. Comparison between the calculated and measured values shows that the design methods are reliable. A new application of the IEEE 112 measurement method is developed and used especially for determination of stray load losses in laboratory measurements. The study shows that, with some special measures, the efficiency of the TLA SynRM is equivalent to that of a high efficiency IM. The power factor of the SynRM at rated load is smaller than that of the IM. However, at lower partial load this difference decreases and this, probably, brings that the SynRM gets a better power factor in comparison with the IM. The big rotor inductance ratio of the SynRM allows a good estimating of the rotor position. This appears to be very advantageous for the designing of the rotor position sensor-less motor drive. In using the FEM designed multi-layer transversally laminated rotor with damper windings it is possible to design a directly network driven motor without degrading the motorefficiency or power factor compared to the performance of the IM.

Induction motor versus permanent magnet synchronous motor in motion control applications: a comparative study

High dynamic performance of an electric motor is a fundamental prerequisite in motion control applications, also known as servo drives. Recent developments in the field of microprocessors and power electronics have enabled faster and faster movements with an electric motor. In such a dynamically demanding application, the dimensioning of the motor differs substantially from the industrial motor design, where feasible characteristics of the motor are for example high efficiency, a high power factor, and a low price. In motion control instead, such characteristics as high overloading capability, high-speed operation, high torque density and low inertia are required. The thesis investigates how the dimensioning of a high-performance servomotor differs from the dimensioning of industrial motors. The two most common servomotor types are examined; an induction motor and apermanent magnet synchronous motor. The suitability of these two motor types indynamically demanding servo applications is assessed, and the design aspects that optimize the servo characteristics of the motors are analyzed. Operating characteristics of a high performance motor are studied, and some methods for improvements are suggested. The main focus is on the induction machine, which is frequently compared to the permanent magnet synchronous motor. A 4 kW prototype induction motor was designed and manufactured for the verification of the simulation results in the laboratory conditions. Also a dynamic simulation model for estimating the thermal behaviour of the induction motor in servo applications was constructed. The accuracy of the model was improved by coupling it with the electromagnetic motor model in order to take into account the variations in the motor electromagnetic characteristics due to the temperature rise.

An Evaluation of the Paper Profile - a comparative assessment of the applicability of an emerging environmental communication tool in pulp and paper industry

Diplomityön tavoitteena oli arvioida uutta sellu-, paperi- ja kartonkiteollisuuden Paper Profile -ympäristötuoteselostetta. Paper Profilen tarkoituksena on tarjota paperiteollisuuden asiakkaille ja muille kiinnostuneilla sidosryhmille yhtenäistä ympäristöinformaatiota koskien paperituotteiden koostumusta ja tuotteiden tärkeimpiä ympäristöparametrejä. Työn tärkein tavoite oli arvioida kriittisesti Paper Profilea ja verrata konseptia ISO:n, Kansainvälisen stardardisoimisliiton tuoteselosteeseen sekä löytää konseptien yhtäläisyydet ja erot. Tärkein tehtävä oli tunnistaa ne avaintekijät, joiden avulla Paper Profile -tuoteselostetta voitaisiin pitää yhtenevänä ISO/TR 14025 teknisen raportin kanssa. Lisäksi Paper Profile -tuoteselosteen mahdolliset kehittämistarpeet arvioitiin ISO-tuoteselosteen näkökulmasta. Työn toinen tavoite oli kerätä ja analysoida uuteen tuoteselosteeseen liittyvä asiakaspalaute ja verrata sitä Stora Enson tehtaiden ympäristöpäälliköiden antamiin Paper Profilea koskeviin kommentteihin. Työn tuloksena huomattiin, että Paper Profile -konsepti sellaisenaan ei ole kovin informatiivinen vaan tuoteseloste jättää monia ympäristökysymyksiä avoimeksi. Siitä huolimatta Paper Profile tarjoaa riittävän taustan eri paperituotteiden ympäristökuormitusten keskinäiselle vertailuille. Konseptin viestinnällinen näkökulma paranisi huomattavasti, jos tuoteselosteeseen lisättäisiin kolmannen osapuolen verifiointi. Lisäksi referenssiarvot kertoisivat asiakkaille paremmin esitettyjen parametrien taustoista. Stora Enson tehtaiden ympäristöpäälliköiden, samoin kuin asiakkaidenkin mielestä Paper Profile on yleisesti ottaen potentiaalinen ympäristöviestinnän työkalu, mutta silti konseptiin ehdotettiin joitakin pieniä muutoksia. Avoinna olevat metsäsertifiointikysymykset ja niiden puutteellinen tiedottaminen tuoteselosteessa puhututtivat sekä tehtaiden henkilöstöä että yritysasiakkaita.

Technical Aspects of Internet-Shopping, Comparative study in Finland/Russia

Isot ja keskikokoiset yritykset harkitsevat sähköistä kaupankäyntiä Internetissä, Internet - kauppojen muodossa. Organisaatiot pyrkivät kilpailukykyiseen ja moderniin tyyliin kaupankäynnissä sekä yrityksen eri prosessien automatisointiin. Yrityksen on onnistuttava uusimpien tekniikoiden ja työkalujen omaksumisessa kilpailukykynsä parantamiseksi. Sähköinen kaupankäynti on suhteellisen uusi tekniikka, joka mahdollistaa kaupankäynnin esittämisen uudessa, sähköisessä muodossa. Tämä työ sisältää katsauksen yrityksen mahdollisiin sähköisen kaupankäynnin eri muotoihin. Työ sisältää mahdollisia ratkaisuja Internet-kaupan rakentamiseen, sähköisen kaupankäynnin hallintaan sekä erityyppisten Internet- kauppojen kuvauksia. Sähköisen kaupankäynnin ongelmat ovat myös tarkastelussa. Välttämättömät asiat sähköisen kaupankäynnin perustamiseksi on lueteltu. Työn kokeellinen osuus sisältää vertailututkimusta sähköisen kaupankäynnin muodoista Suomessa ja Venäjällä. Sähköisen kaupankäynnin ongelmat, niiden mahdolliset ratkaisut, eroavaisuudet sekä samankaltaisuudet molempien maiden välillä on esitetty tässä työssä. Työssä on arvioitu Internet-kaupan kehittämistä sekä edistämistä esimerkein. Tutkimuksen tulokset on esitetty.

Phylogeography and population genetics of north European Atlantic salmon (Salmo salar L.)

Although abundant in the number of individuals, the Atlantic salmon may be considered as a threatened species in many areas of its native distribution range. Human activities such as building of power plant dams, offshore overfishing, pollution, clearing of riverbeds for timber floating and badly designed stocking regimes have diminished the distribution of Atlantic salmon. As a result of this, many of the historical populations both in Europe and northern America have gone extinct or are severely depressed. In fact, only 1% of Atlantic salmon existing today are of natural origin, the rest being farmed salmon. All of this has lead to a vast amount of research and many restoration programmes aiming to bring Atlantic salmon back to rivers from where it has vanished. However, many of the restoration programmes conducted thus far have been unsuccessful due to inadequate scientific research or lack of its implementation, highlighting the fact that more research is needed to fully understand the biology of this complex species. The White and Barents Seas in northwest Russia are among the last regions in Europe where Atlantic salmon populations are still stable, thus forming an important source of biodiversity for the entire European region. Salmon stocks from this area are also of immense economic and social importance for the local people in the form of fishing tourism. The main aim of this thesis was to elucidate the post-glacial history and population genetic structure of north European and particularly northwest Russian Atlantic salmon, both of which are aspects of great importance for the management and conservation of the species. Throughout the whole thesis, these populations were studied by utilizing microsatellites as the main molecular tool. One of the most important discoveries of the thesis was the division of Atlantic salmon from the White and Barents Seas into four separate clusters, which has not been observed in previous studies employing nuclear markers although is supported by mtDNA studies. Populations from the western Barents Sea clustered together with the northeast Atlantic populations into a clearly distinguishable group while populations from the White Sea and eastern Barents Sea were separated into three additional groups. This has important conservation implications as this thesis clearly indicates that conservation of populations from all of the observed clusters is warranted in order to conserve as much of the genetic diversity as possible in this area. The thesis also demonstrates how differences in population life histories within a species, migratory behaviour in this case, and in their phylogeographic origin affect the genetic characteristics of populations, namely diversity and divergence levels. The anadromous populations from the Atlantic Ocean, White Sea and Barents Sea possessed higher levels of genetic diversity than the anadromous populations form the Baltic Sea basin. Among the non-anadromous populations the result was the opposite: the Baltic freshwater populations were more variable. This emphasises the importance of taking the life history of a population into consideration when developing conservation strategies: due to the limited possibilities for new genetic diversity to be generated via gene flow, it is expected that freshwater Atlantic salmon populations would be more vulnerable to extinction following a population crash and thus deserve a high conservation status. In the last chapter of this thesis immune relevant marker loci were developed and screened for signatures of natural selection along with loci linked to genes with other functions or no function at all. Also, a novel landscape genomics method, which combines environmental information with molecular data, was employed to investigate whether immune relevant markers displayed significant correlations to various environmental variables more frequently than other loci. Indications of stronger selection pressure among immune-relevant loci compared to non-immune relevant EST-linked loci was found but further studies are needed to evaluate whether it is a common phenomenon in Atlantic salmon.

Profiles of Second Language Learners in Bilingual Education: A Comparative Study of the Characteristics of Finnish and American Students

The purpose of this comparative study is to profile second language learners by exploring the factors which have an impact on their learning. The subjects come from two different countries: one group comes from Milwaukee, US, and the other from Turku, Finland. The subjects have attended bilingual classes from elementary school to senior high school in their respective countries. In the United States, the subjects (N = 57) started in one elementary school from where they moved on to two high schools in the district. The Finnish subjects (N = 39) attended the same school from elementary to high school. The longitudinal study was conducted during 1994-2004 and combines both qualitative and quantitative research methods. A Pilot Study carried out in 1990-1991 preceded the two subsequent studies that form the core material of this research. The theoretical part of the study focuses first on language policies in the United States and Finland: special emphasis is given to the history, development and current state of bilingual education, and the factors that have affected policy-making in the provision of language instruction. Current language learning theories and models form the theoretical foundation of the research, and underpin the empirical studies. Cognitively-labeled theories are at the forefront, but sociocultural theory and the ecological approach are also accounted for. The research methods consist of questionnaires, compositions and interviews. A combination of statistical methods as well as content analysis were used in the analysis. The attitude of the bilingual learners toward L1 and L2 was generally positive: the subjects enjoyed learning through two languages and were motivated to learn both. The knowledge of L1 and parental support, along with early literacy in L1, facilitated the learning of L2. This was particularly evident in the American subject group. The American subjects’ L2 learning was affected by the attitudes of the learners to the L1 culture and its speakers. Furthermore, the negative attitudes taken by L1 speakers toward L2 speakers and the lack of opportunities to engage in activities in the L1 culture affected the American subjects’ learning of L2, English. The research showed that many American L2 learners were isolated from the L1 culture and were even afraid to use English in everyday communication situations. In light of the research results, a politically neutral linguistic environment, which the Finnish subjects inhabited, was seen to be more favorable for learning. The Finnish subjects were learning L2, English, in a neutral zone where their own attitudes and motivation dictated their learning. The role of L2 as a means of international communication in Finland, as opposed to a means of exercising linguistic power, provided a neutral atmosphere for learning English. In both the American and Finnish groups, the learning of other languages was facilitated when the learner had a good foundation in their L1, and the learning of L1 and L2 were in balance. Learning was also fostered when the learners drew positive experiences from their surroundings and were provided with opportunities to engage in activities where L2 was used.

The relationship between first-order capabilities and online innovations. A comparative case study on the publishing sector.

The objective of this thesis was to study the relationship between firstorder capabilities and online innovations. First-order capabilities can be divided into market and technology capabilities, and they play an important role in the production of innovations. The study was carried out in publishing industry, where many changes have taken place in the online environment during the last few years. In the empirical research, four companies were studied, two magazine publishers and two newspaper publishers. The analysis was done in two phases; first every case was analyzed alone and then the cases were compared in cross-case analysis. The most important finding was the positive impact of market capability to the production of online innovations. The study also increased understanding about the relationship between market and technology capabilities and online innovations in general.

A Comparative Study of the Effectiveness of a Prefabricated Appliance and a Stabilization Appliance in the Treatment of Myofascial pain and Headache

The aim of this thesis was to evaluate the short- and long-term effectiveness of a prefabricated occlusal appliance (R) on patients with myofascial pain and headache by comparing it with the treatment of the stabilization appliance (S). Another aim was to evaluate the effect of appliance treatment on stress-related salivary parameters like cortisol and IgA, as well as on flow rate values in these patients. Sixty-five patients diagnosed with myofascial temporomandibular disorder (TMD) pain, of whom 94% suffered concomitantly from headache, at two centres for Stomatognathic Physiology, one in Sweden and one in Finland, were included in this randomized controlled trial using Research Diagnostic Criteria for TMD (RDC/TMD), with history questionnaires and clinical examinations performed at baseline and at 6- and 10-weeks, and 6- and 12-month follow-ups. Patients were randomly assigned either to the R or the S group. Treatment outcome was measured according to IMMPACT (Initiative on Methods, Measurements, and Pain Assessment in Clinical Trials), i.e. four chronic pain outcome domains: pain intensity, overall improvement, physical and emotional functioning. Changes in frequency and intensity of headache were recorded. Thirty-nine patients participated in the saliva study. Salivary analyses were performed at 6 and 10 weeks. The results revealed no differences between groups at baseline. At all follow-ups, all four outcome measures, as well as frequency and intensity of headache, showed statistically significant within-group improvement compared to baseline, without significant differences between groups. No treatment-induced changes in saliva parameters could be registered. In conclusion, the effectiveness of the prefabricated appliance seemed to be similar to that of the stabilization appliance in alleviating myofascial pain, and frequency and intensity of headache, in the short as well as the long term. However, no changes in salivary parameters were observed during treatment.