Mass transfer and particleinteractions in granular systems and suspension flows

The purpose of this study was to investigate some important features of granular flows and suspension flows by computational simulation methods. Granular materials have been considered as an independent state ofmatter because of their complex behaviors. They sometimes behave like a solid, sometimes like a fluid, and sometimes can contain both phases in equilibrium. The computer simulation of dense shear granular flows of monodisperse, spherical particles shows that the collisional model of contacts yields the coexistence of solid and fluid phases while the frictional model represents a uniform flow of fluid phase. However, a comparison between the stress signals from the simulations and experiments revealed that the collisional model would result a proper match with the experimental evidences. Although the effect of gravity is found to beimportant in sedimentation of solid part, the stick-slip behavior associated with the collisional model looks more similar to that of experiments. The mathematical formulations based on the kinetic theory have been derived for the moderatesolid volume fractions with the assumption of the homogeneity of flow. In orderto make some simulations which can provide such an ideal flow, the simulation of unbounded granular shear flows was performed. Therefore, the homogeneous flow properties could be achieved in the moderate solid volume fractions. A new algorithm, namely the nonequilibrium approach was introduced to show the features of self-diffusion in the granular flows. Using this algorithm a one way flow can beextracted from the entire flow, which not only provides a straightforward calculation of self-diffusion coefficient but also can qualitatively determine the deviation of self-diffusion from the linear law at some regions nearby the wall inbounded flows. Anyhow, the average lateral self-diffusion coefficient, which was calculated by the aforementioned method, showed a desirable agreement with thepredictions of kinetic theory formulation. In the continuation of computer simulation of shear granular flows, some numerical and theoretical investigations were carried out on mass transfer and particle interactions in particulate flows. In this context, the boundary element method and its combination with the spectral method using the special capabilities of wavelets have been introduced as theefficient numerical methods to solve the governing equations of mass transfer in particulate flows. A theoretical formulation of fluid dispersivity in suspension flows revealed that the fluid dispersivity depends upon the fluid properties and particle parameters as well as the fluid-particle and particle-particle interactions.

Rahavirta-analyysit, erityisesti kassavirtalaskelma, kunnan talouden ohjauksen apuvälineenä

 The aim of this research was to determine whether a cash basis financial statement would give additional value for the financial management of a local government and whether the cash flow statement would assist in getting a true and fair view of the financial position of the local government. The goal was to develop a cash flow statement and cash flow based key ratios for the needs of local government and the possibilities to utilise them were studied. In the theoretical part of this work, the literature review section,municipal economy, the main objectives and key ratios of financial control in municipal financial management, central control systems, control instruments and different financial statements were studied. In the empirical part the possibilities of utilising the information of these different financial statements as onecontrol instrument of municipal financial management were compared. Also empirical testing of the exploitation of these financial statements was carried out. The suggestion for municipal cash flow statement and its key ratios were defined on the basis of the theoretical and empirical parts. The results show that the municipal cash flow statement is most effective in a three-part form: cash flow from ordinary operations, cash flow from investments and funding cash flow. The added value of the cash flow statement comes from its ability to better attest the financial ability for investments better than the profit and loss account. Themunicipal cash flow statement is therefore especially suitable when analysing of the sufficiency of money. In addition to absolute ratios, such as the financial margin, also relative cash basis ratios such as the financial margin percentage, liquidity percentage and investment income financing percentage are important. Also the simple cash based calculation about receiving and using money is applicable to local governments. The statement could be a part of municipal financial statements, budgets and annual reports. On the other hand, working capital flow and expense and revenue flow statements do not give added value for municipal financial management.

Dynamics of Appropriability - Finding a Balance between Efficiency and Strength in the Appropriability Regime

Building and sustaining competitive advantage through the creation of market imperfections is challenging in a constantly changing business environment - particularly since the sources of such advantages are increasingly knowledge-based. Facilitated by improved networks and communication, knowledge spills over to competitors more easily than before,thus creating an appropriability problem: the inability of an innovating firm to utilize its innovations commercially. Consequently, as the importance of intellectual assets increases, their protection also calls for new approaches. Companies have various means of protection at their disposal, and by taking advantage of them they can make intangibles more non-transferable and prevent, or at leastdelay, imitation of their most crucial intellectual assets. However, creating barriers against imitation has another side to it, and the transfer of knowledge in situations requiring knowledge sharing may be unintentionally obstructed. Theaim of this thesis is to increase understanding of how firms can balance knowledge protection and sharing so as to benefit most from their knowledge assets. Thus, knowledge protection is approached through an examination of the appropriability regime of a firm, i.e., the combination of available and effective means ofprotecting innovations, their profitability, and the increased rents due to R&D. A further aim is to provide a broader understanding of the formation and structure of the appropriability regime. The study consists of two parts. The first part introduces the research topic and the overall results of the study, and the second part consists of six complementary research publications covering various appropriability issues. The thesis contributes to the existing literature in several ways. Although there is a wide range of prior research on appropriability issues, a lot of it is restricted either to the study of individual appropriability mechanisms, or to comparing certain features of them. These approaches are combined, and the relevant theoretical concepts are clarified and developed. In addition, the thesis provides empirical evidence of the formation of the appropriability regime, which is consequently presented as an adaptive process. Thus, a framework is provided that better corresponds to the complex reality of the current business environment.

Propagation of the Ignition Front against Airflow in Packed Beds of Wood Particles

Combustion of wood is increasing because of the needs of decreasing the emissions of carbon dioxide and the amount of waste going to landfills. Wood based fuels are often scattered on a large area. The transport distances should be short enough to prevent too high costs, and so the size of heating and power plants using wood fuels is often rather small. Combustion technologies of small-size units have to be developed to reach efficient and environmentally friendly energy production. Furnaces that use different packed bed combustion or gasification techniques areoften most economic in small-scale energy production. Ignition front propagation rate affects the stability, heat release rate and emissions of packed bed combustion. Ignition front propagation against airflow in packed beds of wood fuels has been studied. The research has been carried out mainly experimentally. Theoretical aspects have been considered to draw conclusions about the experimental results. The effects of airflow rate, moisture content of the fuel, size, shape and density of particles, and porosity of the bed on the propagation rate of the ignition front have been studied. The experiments were carried out in a pot furnace. The fuels used in the experiments were mainly real wood fuels that are often burned in the production of energy. The fuel types were thin wood chips, saw dust, shavings, wood chips, and pellets with different sizes. Also a few mixturesof the above were tested. Increase in the moisture content of the fuel decreases the propagation rates of the ignition front and makes the range of possible airflow rates narrower because of the energy needed for the evaporation of water and the dilution of volatile gases due to evaporated steam. Increase in the airflow rate increases the ignition rate until a maximum rate of propagation is reached after which it decreases. The maximum flame propagation rate is not always reached in stoichiometric combustion conditions. Increase in particle size and density transfers the optimum airflow rate towards fuel lean conditions. Mixing of small and large particles is often advantageous, because small particles make itpossible to reach the maximum ignition rate in fuel rich conditions, and large particles widen the range of possible airflow rates. A correlation was found forthe maximum rate of ignition front propagation in different wood fuels. According to the correlation, the maximum ignition mass flux is increased when the sphericity of the particles and the porosity of the bed are increased and the moisture content of the fuel is decreased. Another fit was found between sphericity and porosity. Increase in sphericity decreases the porosity of the bed. The reasons of the observed results are discussed.

Perusterveydenhuollon ja erikoissairaanhoidon käytön seuranta ja ennakointi kuntanäkökulmasta

Follow-up of utilisation and prediction of primary health care and hospital care from the municipality point of view. Planning, follow-up, and evaluation of primary health care within municipality entail comprehensive information about factors that influence health. In addition to populationbased research, various statistical data and registries serve as sources of information. The present study examined utilisation of primary health care and hospital care with the existing databases, registries, and categorization of Diagnosis Related Groups (DRGs) from the municipality (purchaser) point of view. Research involving the cases of Paimio, Sauvo, and Turku as examples of municipalities pointed out that, even in the small municipalities, it is possible to assess and predict health services to be offered to the inhabitants by following databases and registries. Health-related databases and registries include a plenty of possible uses that have not adequately been employed at the level of municipality. Descriptive futures research and community analysis formed the framework of the study. Descriptive futures research may be used to establish predictions based on past developmental traditions, and quantitative time trend analyses may be employed to make estimations about future events. Community analysis will assist in making conclusions about population- based health care needs, in assessing the functionality or effectiveness of the health care system, and in appropriately targeting limited resources. The aim of the present study was to describe the health service profile so that the arrangements and planning of health services as well as the contract negotiations of hospital care become easier within municipalities. Another aim was to assess the application of Hilmo (registry for posting hospital care periods), Aitta and Sotka (statistical databases) for the purposes of resource planning in the procurement of hospital care. A third aim was to evaluate how the system of the DRGs adapts in the prediction of retaining health services within short (1-year), intermediate (5-year) and long range (10-15-year) intervals. The findings indicated that the follow-up of primary health care utilisation combined with follow-up of hospital care utilisation allows municipalities to plan and predict health services when databases are applied. Information about the past contacts with the databases has indicated that the health care culture and incidence of disease change rather slowly in the area of investigation. For the purposes of health care research, it is recommended that methods of application used in making predictions about health care utilisation need to be further developed

Liikuntakulutus kaupunkilaislasten ja -nuorten liikuntasuhteessa

Tilanteessa, jossa liikuntainstituutiot joutuvat aiempaa tiukemmin taistelemaan vetovoimaisuudestaan muiden vapaa-ajan elämysteollisuuden toimintamuotojen kanssa ja jossa ihmisten valinnat ja päätökset ohjautuvat pitkälti asioissa kohdattujen kulttuuristen merkitysten perusteella, ei liikunnan tutkimista vain fyysisenä harrastuksena voida enää pitää riittävänä lähestymistapana. Tämän tutkimuksen tarkastelunäkökulmaksi valittiin kaupunkilaislasten ja -nuorten suhde liikuntaan sekä liikuntakulutuksen rooli sen rakentumisessa. Liikuntasuhteen tarkoittaessa kiinnittymis- ja suhtautumistapojen kokonaisuutta, jonka kautta yksilö kohtaa ja arvottaa liikunnan sosiaalisia maailmoja kulttuurisine merkitysrakenteineen, voidaan kulttuurin- ja kulutustutkimukselliset vaikutteet todeta tutkimusotteessa keskeisiksi. Turussa keväällä 2004 survey-tekniikalla toteutettuun tutkimukseen osallistui 442 viidesluokkalaista 11 alakoulusta ja 380 yhdeksäsluokkalaista 11 yläkoulusta (N = 822). Vastaukset mahdollistivat liikunta- ja penkkiurheilupalvelujen sekä liikuntahyödykkeiden kulutusmääriä ja -sisältöjä koskevien tietojen päivittämisen ja täydentämisen. Uudet tutkimukselliset avaukset kohdistuivat liikuntakulutuksen eri osa-alueilla kohdattujen kulttuuristen merkitysulottuvuuksien paljastamiseen sekä liikuntasuhteen vahvuutta selittävien kulutusmuotojen ja merkityspainotusten löytämiseen. Kouluikäisille liikkumisessa itsessään osoittautui tärkeimmäksi hyvän olon ja mielen merkitys. Myös liikkumisen välineellistä merkitystä hyvinvoinnille arvostettiin. Välittömässä penkkiurheilussa painotettiin lajisuoritusten ja välitetyssä penkkiurheilussa arjesta irtautumisen merkityskokonaisuutta. Liikuntahyödykkeiden hankinnassa tärkeimpänä kohdattiin hyödykkeen välinearvo liikuntasuorituksille. 70 prosentille vastaajista liikunta oli vähintäänkin tärkeä elämänasia, minkä tulkittiin indikoineen vahvaa liikuntasuhdetta. Liikuntakulutuksen ilmikäyttäytymismuodoista seura- ja omatoimiliikunnan tiheys sekä liikuntatekstiilien käyttötiheys muissa kuin liikuntatilanteissa selittivät luotettavasti liikuntasuhteen vahvuutta. Liikuntakulutuksessa kohdattujen merkitysrakenteiden osalla menestyshalun sekä hyvän olon ja mielen tärkeys omakohtaisessa liikkumisessa, samoin kuin liikunta-asiantuntijuuden tärkeys välitetyn penkkiurheilun harjoittamisessa olivat merkitsevimmät liikuntasuhteen vahvuuden selittäjät. Kulutuksen lisäämiseksi kaikessa liikuntapalvelu- ja hyödyketarjonnassa tulee huomioida kohderyhmän sisäistämät merkitysrakenteet. Kansanterveyden kannalta toimenpiteet kouluikäisten saattamiseksi organisoidun liikunnan pariin näyttävät hyödyllisimmiltä. Jatkossa niin määrällisellä kuin laadullisella merkitystutkimuksella on mahdollisuus avartaa liikuntakäyttäytymisen ymmärtämistä muidenkin kohderyhmien osalla.

Lasten luvaton tuli – perusasteen oppilaat sytyttelijöinä

Tutkimus lasten ja nuorten luvattomasta tulen käsittelystä perustuu näkemykseen siitä, että ilmiöön voidaan puuttua tehokkaasti interventioin, jos toiminta havaitaan ajoissa. Ilmiötä sävyttää teon salailu ja neutralisaatio eli vähättely. Tulella tehtyjen tuhotöiden lisääntymistä ja muuttumista aggressiivisemmaksi voidaan ennalta ehkäistä ongelman tunnistamisella ja reagoimalla lasten häiriökäytökseen. Lasten ja nuorten luvatonta tulen käyttöä ei ole tutkittu Suomessa aiemmin. Työn ensimmäisessä osiossa tarkastellaan luvattomaan tulen käsittelyyn liittyviä teorioita (esim. Fineman 1980, 1995), kansainvälisiä näkökohtia, teonpiirteitä ja yksilön sisäisiä prosesseja. Lisäksi tarkastellaan perheen, koulun ja ystäväpiirin osuutta ilmiöön, niin sanotun Oregonin mallin mukaisesti (Oregon Treatment Strategies Task Force 1996, 16 – 47). Työn empiirisessä osiossa ilmiötä ja sen ilmenemistä lasten ja nuorten keskuudessa kuvataan oppilaiden, vanhempien ja opettajien näkökulmasta. Tutkimukseen osallistui 661 oppilasta perusasteen toiselta, viidenneltä ja kahdeksannelta luokalta, 341 vanhempaa ja 22 koulun työntekijää. Oppilaiden ja vanhempien aineisto kerättiin survey-tutkimuksella ja opettajat tutkittiin haastattelumenetelmällä. Lasten luvaton tulen käyttö on yleisempää kuin aiemmin on luultu. Vielä viidenteen luokkaan mennessä luvaton tulen käsittely oli yleisempää pojille kuin tytöille, mutta murrosikään tultaessa sukupuolierot vähenivät. Pojista 37 % ja tytöistä 25 % raportoi käsitelleensä tulta luvattomasti. Kaikkiaan kolmasosa oppilaista raportoi leikkineensä tulella. Yleisin tulen sytyttelypaikka oli oma koti tai kodin lähiympäristö, josta tulentekovälineet yleisimmin hankittiin pyytämällä tai ottamalla. Luvattomasti tulta käsitelleet oppilaat olivat häirinneet oppitunteja. Tilastollisesti merkitsevimmin runsasta luvatonta tulen käsittelyä ennusti omien tulentekovälineiden omistaminen ja häiriökäyttäytyminen koulussa. Vanhemmat eivät pitäneet lastensa tulen käyttöä merkittävänä vaarana. Aikuisten suhtautumista lasten luvattomaan tulen käyttöön sävytti tekojen vähättely eli neutralisaatio; vähättelyilmiö oli yhteinen sekä lapsille itselleen, vanhemmille että viranomaisille. Kasvattajilla ei ollut käytössään tehokkaita interventiomenetelmiä ongelman ratkaisemiseen. Viranomaisyhteistyöstä raportoitiin vain vähän. Pelastusviranomaisia ei juurikaan käytetty lasten luvattoman tulen käsittelyn interventiossa. Interventiota sävytti aikuisten käsitysten mukaan tapauskohtaisuus ja sattumanvaraisuus.

Sosiaalityö ja maahanmuuttajat. Lastensuojelun ammattilaisten ja asiakkaiden vuorovaikutus ja tulkinnat

Tutkimuksen tavoitteena oli tuottaa tietoa siitä, mitä maahanmuuttajia koskevat erityiskysymykset suomalaisessa lastensuojelun sosiaalityössä ovat ja miten näitä kysymyksiä lastensuojelussa käsitellään. Teoreettismetodologisena viitekehyksenä on sosiaalinen konstruktionismi. Etnisten suhteiden tutkimusperinteessä työ paikantuu keskusteluun, jossa kulttuuri ja etnisyys nähdään sosiaalisesti rakentuvina ja muuntuvina. Analyysissä sovelletaan diskurssianalyyttistä metodologiaa. Tutkimus rakentuu yhteenveto-osiosta ja neljästä artikkelista. Maahanmuuttajasosiaalityötä ja lastensuojelua tarkastellaan sosiaalityöntekijöiden, muiden ammattilaisten ja asiakkaiden kielenkäytön kautta. Aineisto koostuu 11 lastensuojelun asiakaskeskustelusta ja niiden jälkeen keskustelun osapuolille tehdyistä haastatteluista, joita on yhteensä 35. Tutkimuksessa analysoidaan seuraavia kysymyksiä: Miten sosiaalityöntekijät tulkitsevat maahanmuuttajasosiaalityön erityisyyttä oman ammatillisen tehtävänsä näkökulmasta? Minkälaisia ominaisuuksia sosiaalityöntekijät rakentavat maahanmuuttaja-asiakkaille? Miten lastensuojelun keskusteluissa puhutaan monikulttuurisuuteen liittyvistä teemoista, kuten erilaisuudesta ja samanlaisuudesta sekä kulttuuri- ja rasismikysymyksistä? Miten maahanmuuttajalasten ja -nuorten osallisuus lastensuojelun asiakaskeskusteluissa rakentuu aikuisten ja lasten itsensä tuottamana? Mitä ja miten maahanmuuttajalapset ja -nuoret puhuvat kokemuksistaan lastensuojelussa ja suomalaisessa yhteiskunnassa? Maahanmuuttajien erityiskysymyksiä ovat kieleen, kulttuuriin ja valtayhteiskunnan toimintaan liittyvät ymmärtämisvaikeudet, kokemukset arkipäivän rasismista sekä perheen ja yhteisön merkittävä, osin ristiriitainen rooli. Lapsilla ja nuorilla kulttuuri on muuntuvaa ja jatkuvien neuvottelujen kohteena. Aineiston lastensuojelutilanteiden taustalla on usein kouluympäristöön liittyviä vaikeuksia. Haastatteluissa lapset kertovat kokemuksistaan ja toimijuudestaan perheeseen, yhteisöön ja kouluun paikantuvissa tilanteissa. Asiakaskeskusteluissa lasten puhuja-asema on usein heikko, jos aikuiset eivät aktiivisesti vahvista sitä. Jotkut lapset ottavat itse vahvan puhuja-aseman. Asiakaskeskusteluissa maahanmuuttajien erityiskysymyksistä puhutaan harvoin eksplisiittisesti. Haastatteluissa sosiaalityöntekijät enemmän tai vähemmän tietoisesti paikantavat maahanmuuttajasosiaalityötä vieraannuttavaan, sopeuttavaan, tasa-arvoistavaan, kulttuuritietoiseen, rasismitietoiseen ja osallistavaan kehykseen. Kehykset nostavat sosiaalityön tavoitteista, menetelmistä ja asiakkaasta keskeisiksi erilaisia asioita. Tulkinnat ovat muuntuvia, vaikka osoittavat myös tiettyä säännönmukaisuutta. Kulttuuri on keskeinen käsite erilaisuuden ja samanlaisuuden ymmärtämiseksi. Sekä työntekijät että asiakkaat perustelevat toivottavia elämäntapoja "omalla kulttuurillaan" ja selittävät ongelmia ”erilaisella kulttuurilla”. Kulttuurin käsitettä voidaan myös käyttää työvälineenä asiakaskeskusteluissa avattaessa asiakkaan omaa näkökulmaa korostavaa dialogia. Perheen ja kulttuurisen yhteisön merkitys on tärkeää arvioida lapsen ja nuoren hyvinvoinnin ja kulttuurisen identiteetin kehittymisen näkökulmasta. Sosiaalityöntekijöillä on merkittävä välittäjän rooli yhtäältä valtayhteiskunnan ja maahanmuuttaja-asiakkaiden, toisaalta vanhempien, yhteisöjen sekä lasten ja nuorten välillä. Lastensuojelussa haasteena on arkipäivän rasismin tiedostaminen sekä siihen pureutuvien työmenetelmien kehittäminen.

Gas-phase photocatalytic oxidation of volatile organic compounds

Substances emitted into the atmosphere by human activities in urban and industrial areas cause environmental problems such as air quality degradation, respiratory diseases, climate change, global warming, and stratospheric ozone depletion. Volatile organic compounds (VOCs) are major air pollutants, emitted largely by industry, transportation and households. Many VOCs are toxic, and some are considered to be carcinogenic, mutagenic, or teratogenic. A wide spectrum of VOCs is readily oxidized photocatalytically. Photocatalytic oxidation (PCO) over titanium dioxide may present a potential alternative to air treatment strategies currently in use, such as adsorption and thermal treatment, due to its advantageous activity under ambient conditions, although higher but still mild temperatures may also be applied. The objective of the present research was to disclose routes of chemical reactions, estimate the kinetics and the sensitivity of gas-phase PCO to reaction conditions in respect of air pollutants containing heteroatoms in their molecules. Deactivation of the photocatalyst and restoration of its activity was also taken under consideration to assess the practical possibility of the application of PCO to the treatment of air polluted with VOCs. UV-irradiated titanium dioxide was selected as a photocatalyst for its chemical inertness, non-toxic character and low cost. In the present work Degussa P25 TiO2 photocatalyst was mostly used. In transient studies platinized TiO2 was also studied. The experimental research into PCO of following VOCs was undertaken: - methyl tert-butyl ether (MTBE) as the basic oxygenated motor fuel additive and, thus, a major non-biodegradable pollutant of groundwater; - tert-butyl alcohol (TBA) as the primary product of MTBE hydrolysis and PCO; - ethyl mercaptan (ethanethiol) as one of the reduced sulphur pungent air pollutants in the pulp-and-paper industry; - methylamine (MA) and dimethylamine (DMA) as the amino compounds often emitted by various industries. The PCO of VOCs was studied using a continuous-flow mode. The PCO of MTBE and TBA was also studied by transient mode, in which carbon dioxide, water, and acetone were identified as the main gas-phase products. The volatile products of thermal catalytic oxidation (TCO) of MTBE included 2-methyl-1-propene (2-MP), carbon monoxide, carbon dioxide and water; TBA decomposed to 2-MP and water. Continuous PCO of 4 TBA proceeded faster in humid air than dry air. MTBE oxidation, however, was less sensitive to humidity. The TiO2 catalyst was stable during continuous PCO of MTBE and TBA above 373 K, but gradually lost activity below 373 K; the catalyst could be regenerated by UV irradiation in the absence of gas-phase VOCs. Sulphur dioxide, carbon monoxide, carbon dioxide and water were identified as ultimate products of PCO of ethanethiol. Acetic acid was identified as a photocatalytic oxidation by-product. The limits of ethanethiol concentration and temperature, at which the reactor performance was stable for indefinite time, were established. The apparent reaction kinetics appeared to be independent of the reaction temperature within the studied limits, 373 to 453 K. The catalyst was completely and irreversibly deactivated with ethanethiol TCO. Volatile PCO products of MA included ammonia, nitrogen dioxide, nitrous oxide, carbon dioxide and water. Formamide was observed among DMA PCO products together with others similar to the ones of MA. TCO for both substances resulted in the formation of ammonia, hydrogen cyanide, carbon monoxide, carbon dioxide and water. No deactivation of the photocatalyst during the multiple long-run experiments was observed at the concentrations and temperatures used in the study. PCO of MA was also studied in the aqueous phase. Maximum efficiency was achieved in an alkaline media, where MA exhibited high fugitivity. Two mechanisms of aqueous PCO – decomposition to formate and ammonia, and oxidation of organic nitrogen directly to nitrite - lead ultimately to carbon dioxide, water, ammonia and nitrate: formate and nitrite were observed as intermediates. A part of the ammonia formed in the reaction was oxidized to nitrite and nitrate. This finding helped in better understanding of the gasphase PCO pathways. The PCO kinetic data for VOCs fitted well to the monomolecular Langmuir- Hinshelwood (L-H) model, whereas TCO kinetic behaviour matched the first order process for volatile amines and the L-H model for others. It should be noted that both LH and the first order equations were only the data fit, not the real description of the reaction kinetics. The dependence of the kinetic constants on temperature was established in the form of an Arrhenius equation.

On the Analysis and Control of a Linear Synchronous Servomotor with a Flexible Load

Industry's growing need for higher productivity is placing new demands on mechanisms connected with electrical motors, because these can easily lead to vibration problems due to fast dynamics. Furthermore, the nonlinear effects caused by a motor frequently reduce servo stability, which diminishes the controller's ability to predict and maintain speed. Hence, the flexibility of a mechanism and its control has become an important area of research. The basic approach in control system engineering is to assume that the mechanism connected to a motor is rigid, so that vibrations in the tool mechanism, reel, gripper or any apparatus connected to the motor are not taken into account. This might reduce the ability of the machine system to carry out its assignment and shorten the lifetime of the equipment. Nonetheless, it is usually more important to know how the mechanism, or in other words the load on the motor, behaves. A nonlinear load control method for a permanent magnet linear synchronous motor is developed and implemented in the thesis. The purpose of the controller is to track a flexible load to the desired velocity reference as fast as possible and without awkward oscillations. The control method is based on an adaptive backstepping algorithm with its stability ensured by the Lyapunov stability theorem. As a reference controller for the backstepping method, a hybrid neural controller is introduced in which the linear motor itself is controlled by a conventional PI velocity controller and the vibration of the associated flexible mechanism is suppressed from an outer control loop using a compensation signal from a multilayer perceptron network. To avoid the local minimum problem entailed in neural networks, the initial weights are searched for offline by means of a differential evolution algorithm. The states of a mechanical system for controllers are estimated using the Kalman filter. The theoretical results obtained from the control design are validated with the lumped mass model for a mechanism. Generalization of the mechanism allows the methods derived here to be widely implemented in machine automation. The control algorithms are first designed in a specially introduced nonlinear simulation model and then implemented in the physical linear motor using a DSP (Digital Signal Processor) application. The measurements prove that both controllers are capable of suppressing vibration, but that the backstepping method is superior to others due to its accuracy of response and stability properties.

Diffusion of Administrative Innovation: TQM Implementation and Effectiveness in a Global

The main objective of this dissertation is to create new knowledge on an administrative innovation, its adoption, diffusion and finally its effectiveness. In this dissertation the administrative innovation is approached through a widely utilized management philosophy, namely the total quality management (TQM) strategy. TQM operationalizes a self-assessment procedure, which is based on continual improvement principles and measuring the improvements. This dissertation also captures the theme of change management as it analyzes the adoption and diffusion of the administrative innovation. It identifies innovation characteristics as well as organisational and individual factors explaining the adoption and implementation. As a special feature, this study also explores the effectiveness of the innovation based on objective data. For studying the administrative innovation (TQM model), a multinational Case Company provides a versatile ground for a deep, longitudinal analysis. The Case Company started the adoption systematically in the mid 1980s in some of its units. As part of their strategic planning today, the procedure is in use throughout the entire global company. The empirical story begins from the innovation adoption decision that was made in the Case Company over 22 years ago. In order to be able to capture the right atmosphere and backgrounds leading to the adoption decision, key informants from that time were interviewed, since the main target was to clarify the dynamics of how an administrative innovation develops. In addition, archival material was collected and studied, available memos and data relating to the innovation, innovation adoption and later to the implementation contained altogether 20500 pages of documents. A survey was furthermore conducted at the end of 2006 focusing on questions related to the innovation, organization and leadership characteristics and the response rate totalled up to 54%. For measuring the effectiveness of the innovation implementation, the needed longitudinal objective performance data was collected. This data included the profit unit level experience of TQM, the development of the self assessment scores per profit unit and performance data per profit unit measured with profitability, productivity and customer satisfaction. The data covered the years 1995-2006. As a result, the prerequisites for the successful adoption of an administrative innovation were defined, such as the top management involvement, support of the change agents and effective tools for implementation and measurement. The factors with the greatest effect on the depth of the implementation were the timing of the adoption and formalization. The results also indicated that the TQM model does have an effect on the company performance measured with profitability, productivity and customer satisfaction. Consequently this thesis contributes to the present literature (i) by taking into its scope an administrative innovation and focusing on the whole innovation implementation process, from the adoption, through diffusion until its consequences, (ii) because the studied factors with an effect on the innovation adoption and diffusion are multifaceted and grouped into individual, organizational and environmental factors, and a strong emphasis is put on the role of the individual change agents and (iii) by measuring the depth and consistency of the administrative innovation. This deep analysis was possible due to the availability of longitudinal data with triangulation possibilities.

Opettajan monikulttuurinen työ

Teacher's multicultural work The purpose of the present study is to explore teachers’ conceptions of their work as teachers of multicultural students. Teachers’ experiences of multicultural work and conceptions derived from them are part of the teacher’s multicultural competence which is seen as a key component of the teacher’s multicultural teachership. The teacher’s multicultural competence consists of the teacher’s cultural knowledge, pedagogical skills and experiences and attitudes related to multiculturalism. The teacher’s multicultural competence constitutes the basis on which the teacher implements multicultural education. The foundation for the teacher’s work is laid by laws and decrees, curricula, regulations issued by authorities in charge of the education of immigrant students, resources available and other demands and expectations set by the ambient society. The study was conducted in the city of Turku, Finland. The sample consisted of class teachers who taught both immigrant and majority students. Main objects of study in the theoretical part are the multicultural and pluralistic school and the multicultural teachership. The basic assumption is that the multicultural and pluralistic school forms the frame of activity in which the teacher implements multicultural teaching. The research strategy is based on methodological triangulation. The quantitative part of the study was carried out using a questionnaire typical of survey methods. The questionnaire was returned by 71 teachers. The qualitative part was conducted using theme-based interviews typical of phenomenological philosophical research. Of the total of teachers who returned the questionnaire, twelve (12) teachers were selected for interviews. According to the results, the participating teachers enjoyed their work regardless of the ample extra work caused by the students with immigrant backgrounds. The teachers experienced their work as teachers of multicultural student groups as strenuous, yet challenging. Students with immigrant backgrounds had caused many changes in the teacher’s work. The teachers regarded their multicultural skills as inadequate in relation to the demands of the work. They had not received education related to teaching students with immigrant backgrounds, but they were ready for in-service education. The teachers’ previous attitudes concerning immigrant students had been enforced. Teaching experiences strengthened the earlier, both positive and negative, attitudes. The central problems related to multiculturalism in the teacher’s work were caused by the deficient Finnish skills of the students with immigrant background. This was apparent in both teaching and learning as well as in contacts with parents. The teachers reported on relatively few inclusions of multicultural angles in their teaching. However, they believed that they could aid students with different cultural backgrounds in their integration process. At the same time they felt that their own chances to enhance the students’ cultural identities were slim. On the basis of the interviews conducted in connection with the teacher’s multicultural competence, the teachers were divided into three groups: assimilative, indeterminate and integrating multicultural teachers. The present study provides a strong indication that teachers tend to interpret multiculturalism in narrow terms. School activities, such as Finnish as a second language, first language and religious instruction, which were targeted exclusively at immigrant students were in most cases considered adequate. A holistic, cross-disciplinary, all-inclusive multicultural education that would permeate all school activities remains largely unimplemented.

High-Speed Solid-Rotor Induction Machine – Electromagnetic Calculation and Design

Within the latest decade high-speed motor technology has been increasingly commonly applied within the range of medium and large power. More particularly, applications like such involved with gas movement and compression seem to be the most important area in which high-speed machines are used. In manufacturing the induction motor rotor core of one single piece of steel it is possible to achieve an extremely rigid rotor construction for the high-speed motor. In a mechanical sense, the solid rotor may be the best possible rotor construction. Unfortunately, the electromagnetic properties of a solid rotor are poorer than the properties of the traditional laminated rotor of an induction motor. This thesis analyses methods for improving the electromagnetic properties of a solid-rotor induction machine. The slip of the solid rotor is reduced notably if the solid rotor is axially slitted. The slitting patterns of the solid rotor are examined. It is shown how the slitting parameters affect the produced torque. Methods for decreasing the harmonic eddy currents on the surface of the rotor are also examined. The motivation for this is to improve the efficiency of the motor to reach the efficiency standard of a laminated rotor induction motor. To carry out these research tasks the finite element analysis is used. An analytical calculation of solid rotors based on the multi-layer transfer-matrix method is developed especially for the calculation of axially slitted solid rotors equipped with wellconducting end rings. The calculation results are verified by using the finite element analysis and laboratory measurements. The prototype motors of 250 – 300 kW and 140 Hz were tested to verify the results. Utilization factor data are given for several other prototypes the largest of which delivers 1000 kW at 12000 min-1.