To Succeed Is to Believe: Comparison of Self-Efficacy Beliefs in Language Learning between Learner Groups of English and Swedish in Finland

In this thesis, I studied self-efficacy in the learning of English and Swedish in Finland. The theory of self-efficacy, which was created by Albert Bandura, suggests that the beliefs a person has of his or her capabilities in a certain task affect the person’s performance in the task. My aim was to study whether there are differences in self-efficacy beliefs between the learners of English and Swedish, and whether these beliefs correlate with the performance in the language in question. My hypotheses were that the learners of English have higher self-efficacy beliefs than the learners of Swedish and that self-efficacy beliefs correlate with language performance. The study was quantitative, and it consisted of a self-efficacy questionnaire and a language test which were distributed to students of English and Swedish in an upper secondary school in Rovaniemi. The study was answered by 137 students, of whom 93 were learners of English and 44 were learners of Swedish. The results indicated that the learners of English had a higher sense of efficacy than the learners of Swedish. The analysis proved that there was a significant correlation between English students’ self-efficacy and their performance in the language measured by the test and the grades. In addition, a significant correlation existed between Swedish students’ self-efficacy and their grades. However, there was no correlation between the Swedish students’ self-efficacy and their test results. The difference in the self-efficacy beliefs of the two language groups indicates that people in Finland are more confident in using English than Swedish, which also implies that English is more valued in Finnish society than Swedish. It is important to acknowledge the lower self-efficacy beliefs in Swedish because various studies have proven that self-efficacy affects academic achievement. As a suggestion for further research, the self-efficacy beliefs of different language groups could be compared in a qualitative study in order to understand the development of self-efficacy more profoundly.

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.

Potential and Challenges of Analog Reconfigurable Computation in Modern and Future CMOS

In this work, the feasibility of the floating-gate technology in analog computing platforms in a scaled down general-purpose CMOS technology is considered. When the technology is scaled down the performance of analog circuits tends to get worse because the process parameters are optimized for digital transistors and the scaling involves the reduction of supply voltages. Generally, the challenge in analog circuit design is that all salient design metrics such as power, area, bandwidth and accuracy are interrelated. Furthermore, poor flexibility, i.e. lack of reconfigurability, the reuse of IP etc., can be considered the most severe weakness of analog hardware. On this account, digital calibration schemes are often required for improved performance or yield enhancement, whereas high flexibility/reconfigurability can not be easily achieved. Here, it is discussed whether it is possible to work around these obstacles by using floating-gate transistors (FGTs), and analyze problems associated with the practical implementation. FGT technology is attractive because it is electrically programmable and also features a charge-based built-in non-volatile memory. Apart from being ideal for canceling the circuit non-idealities due to process variations, the FGTs can also be used as computational or adaptive elements in analog circuits. The nominal gate oxide thickness in the deep sub-micron (DSM) processes is too thin to support robust charge retention and consequently the FGT becomes leaky. In principle, non-leaky FGTs can be implemented in a scaled down process without any special masks by using “double”-oxide transistors intended for providing devices that operate with higher supply voltages than general purpose devices. However, in practice the technology scaling poses several challenges which are addressed in this thesis. To provide a sufficiently wide-ranging survey, six prototype chips with varying complexity were implemented in four different DSM process nodes and investigated from this perspective. The focus is on non-leaky FGTs, but the presented autozeroing floating-gate amplifier (AFGA) demonstrates that leaky FGTs may also find a use. The simplest test structures contain only a few transistors, whereas the most complex experimental chip is an implementation of a spiking neural network (SNN) which comprises thousands of active and passive devices. More precisely, it is a fully connected (256 FGT synapses) two-layer spiking neural network (SNN), where the adaptive properties of FGT are taken advantage of. A compact realization of Spike Timing Dependent Plasticity (STDP) within the SNN is one of the key contributions of this thesis. Finally, the considerations in this thesis extend beyond CMOS to emerging nanodevices. To this end, one promising emerging nanoscale circuit element - memristor - is reviewed and its applicability for analog processing is considered. Furthermore, it is discussed how the FGT technology can be used to prototype computation paradigms compatible with these emerging two-terminal nanoscale devices in a mature and widely available CMOS technology.

Medication competence of nursing students in Finland

Lääkehoidon turvallinen toteuttaminen edellyttää sairaanhoitajalta hyvää lääkehoidon osaamisperustaa. Sairaanhoitajakoulutuksen tehtävänä on mahdollistaa tämän osaamisen kehittyminen. Kansainvälisissä tutkimuksissa on kuitenkin osoitettu, että lääkehoidon opetuksen laajuudessa, sisällössä ja toteutuksessa on vaihtelevuutta. Aikaisemmissa tutkimuksissa on raportoitu myös puutteita lääkehoidon osaamisessa sekä sairaanhoitajilla että sairaanhoitajaopiskelijoilla. Koulutuksen ja lääkehoidon osaamisen kehittämiseksi lääkehoidon opetuksen ja sairaanhoitajaopiskelijoiden lääkehoidon osaamisen monipuolinen arviointi ja osaamista selittävien tekijöiden tarkastelu on tarpeen. Tämän tutkimuksen tarkoituksena oli i) arvioida lääkehoidon opetusta suomalaisessa sairaanhoitajakoulutuksessa, ii) arvioida sairaanhoitajaopiskelijoiden lääkehoidon osaamista sekä iii) tunnistaa sairaanhoitajaopiskelijan lääkehoidon osaamiseen yhteydessä olevat tekijät. Tutkimus toteutettiin kolmessa vaiheessa. Ensimmäisessä vaiheessa kahden integroidun kirjallisuuskatsauksen kautta määriteltiin tutkimuksen kohteena oleva sairaanhoitajan lääkehoidon osaaminen ja aiemmin tunnistetut sairaanhoitajaopiskelijan lääkehoidon osaamiseen yhteydessä olevat tekijät. Toisessa vaiheessa toteutettiin valtakunnallinen lääkehoidon opetukseen liittyvä kysely hoitotyön koulutusohjelmasta vastaaville koulutuspäälliköille (n=22) ja opettajille (n=136). Tutkimuksen kolmannessa vaiheessa opintojensa alku‐ (n=328) ja loppuvaiheessa olevien sairaanhoitajaopiskelijoiden (n=338) lääkehoidon osaaminen arvioitiin ja osaamiseen yhteydessä olevat tekijät tunnistettiin. Aineistojen analyysissä käytettiin pääosin tilastollisia menetelmiä. Tulosten perusteella lääkehoidon opetuksen laajuus vaihteli eri ammattikorkeakouluissa, mutta opetuksen sisältö oli kuitenkin monipuolista. Lisää huomiota tulisi kiinnittää lääkehoidon teoreettiseen perustaan ja itsehoitoon sekä lääkehoidon ohjaukseen liittyviin sisältöalueisiin. Opiskelijoiden lääkehoidon osaamista arvioitiin säännöllisesti kaikissa ammattikorkeakouluissa. Sairaanhoitajaopiskelijan lääkehoidon osaamista arvioitiin tutkimuksessa tietotestillä, lääkelaskentatehtävillä ja lyhyiden potilastapausten ratkaisemisen avulla. Lääkehoidon osaamiseen yhteydessä olevia tekijöitä tarkasteltiin kolmesta näkökulmasta: 1) yksilölliset tekijät, 2) kliiniseen oppimisympäristöön ja 3) ammattikorkeakouluun liittyvät tekijät. Lääkehoidon teoreettista osaamista arvioivassa tietotestissä opiskelijat vastasivat keskimäärin 72 prosenttiin kysymyksistä täysin oikein; lääkelaskuista täysin oikein oli 74 % ja potilastapauksissa 57 % valitsi parhaan mahdollisen toimintatavan. Tulosten perusteella sairaanhoitajaopiskelijan osaamista selittivät eniten yksilölliset tekijät. Lääkehoidon osaamiseen yhteydessä olevien tekijöiden välillä oli eroa opintojen alussa ja lopussa. Opintojen alkuvaiheessa opiskelijan aikaisempi opintomenestys oli yhteydessä lääkehoidon osaamiseen, kun taas opintojen loppuvaiheessa siihen olivat yhteydessä opiskelijan kyky itseohjautuvaan oppimiseen sekä opiskelumotivaatio. Johtopäätöksenä voidaan todeta tutkimuksen tulosten olevan samansuuntaisia kuin aikaisemmissa tutkimuksissa. Lääkehoidon opetuksen laajuus vaihtelee opetussuunnitelmatasolla, mutta täsmällinen arviointi on vaikeaa opetuksen sisältöjen integroimisen takia. Sairaanhoitajaopiskelijoiden lääkehoidon osaaminen oli hieman parempaa kuin aikaisemmissa tutkimuksissa, mutta osaamisessa on edelleen puutteita. Lääkehoidon opetuksen ja osaamisen kehittäminen edellyttää kansallista ja kansainvälistä tutkimus‐ ja kehittämisyhteistyötä. Tutkimuksen tulokset tukevat lääkehoidon opetuksen sekä osaamisen tutkimusta ja kehittämistä.

Painelajittimen toimintasakeuden nostaminen havupuusellun lajittelussa

Painelajittimien kyky poistaa epäpuhtauksia on parantunut erityisesti roottorien ja sihtirumpujen kehityksen myötä. Painelajittimella pystytään nykyisin poistamaan yhä pienempiä roskapartikkeleja, minkä ansiosta painelajittimilla pystytään korvaamaan pyörrepuhdistimia hienolajittelussa. Nykyään ratkaisevaa on lajittimen mahdollinen toimintasakeus ja energiankulutus, joihin voidaan vaikuttaa roottori- ja sihtiratkaisuin sekä laitteen ajotavalla. Lajittimen toimintasakeutta nostamalla voitaisiin saavuttaa etuja tuotantoprosessissa pienempien virtauksien ja prosessin paremman ajettavuuden vuoksi. Työssä tarkasteltiin painelajittimen rakenneparametreista roottorin ja sihtirummun sekä ajoparametreista syöttösakeuden, massarejektisuhteen, tuotantomäärän ja roottorin kehänopeuden vaikutusta painelajittimen toimintaan. Erityisesti tutkittiin mahdollisuuksia nostaa lajittelusakeutta ja sakeuden nostonvaikutusta lajittimen energiankulutukseen. Sellutehtaaseen rakennetussa koelajitinlinjassa pystyttiin perusrakenteeltaan nykyisenlaisella painelajittimella muuttamalla roottorin ja sihdin rakennetta sekä nostamalla roottorin kehänopeutta lajittelemaan laitteen mitoitustuotannossa massaa korkeimmillaan 4,8 %:n sakeudessa. Suurin saavutettu sakeus, jossa energiankulutusta voidaanpitää hyväksyttävänä oli 4,4%. Nykyisellä ajotavalla ja roottori- ja sihtirakenteella pystyttiin lajittelemaan massaa 3,2 %:ssa. Tuloksista voidaan päätellä, että massan lajittelu yli 5 %:n sakeudessa on mahdollista roottorirakennetta edelleen kehittämällä.

The Role of an Enterprise Portal in Knowledge Management Strategy, Case: Private Equity Investor

Työ tutkii yritysportaalin roolia organisaation tietojohtamisessa. Tutkimusongelman ratkaisemiseksi luodaan viitekehys, jossa yritysportaalin ja tietojohtamisen teoriat linkittyvät. Työn empiirisessä osassa viitekehys on pohjana case-yritykselle rakennettavalle yritysportaalille. Laadullinen tutkimus käsittää teoriaosuuden sekä osallistuvaan case-tutkimukseen perustuvan empiriaosuuden. Työn runko muodostuu kahden vastakkaisen tietojohtamisajattelun vuoropuhelusta, jotka ovat informaatioteknologiaan- ja strategiseen johtamiseen perustuvat näkökulmat. Toimivan tietojohtamismallin täytyy sisältää molemmat aspektit. Jokainen organisaatio tarvitsee informaation hallintaan liittyviä toiminnallisuuksia ja täten eksplisiittisen tiedon hallinta tietojärjestelmien avulla on onnistuneen tietojohtamisen kulmakiviä. Tätä perusinfrastruktuuria on mahdollista laajentaa hiljaisen tiedon hallintaan perustuvilla tietojohtamismenetelmillä. Työn ratkaisu näiden kahden näkemyksen, 'kovan' informaatioteknogiaan painottuvan sekä 'pehmeän' ihmisnäkökulman integrointiin, on yritysportaali. Työssä käytettävä yritysportaalin viitekehys rakentuu kolmeen päätoiminnallisuuteen; sisällönhallintaan, yhteistyöominaisuuksiin ja liiketoimintatiedon hallintaan. Työ todistaa yhteyden viitekehyksen sekä tietojohtamisen perusmallien, kuten tietojohtamisen prosessimallin sekä tietoympäristöjen välillä. Yritysportaali voi täten toimia, ei ainoastaan yksittäisten tietojohtamistyökalujen implementoinnissa, vaan tietojohtamisstrategian luomisen apuna tarjoten alustan tai 'katalyytin' kokonaisvaltaiselle tietojohtamiselle.

Numerical and ExperimentalModelling of Gas Flow and Heat Transfer in the Air Gap of An Electric Machine

This work deals with the cooling of high-speed electric machines, such as motors and generators, through an air gap. It consists of numerical and experimental modelling of gas flow and heat transfer in an annular channel. Velocity and temperature profiles are modelled in the air gap of a high-speed testmachine. Local and mean heat transfer coefficients and total friction coefficients are attained for a smooth rotor-stator combination at a large velocity range. The aim is to solve the heat transfer numerically and experimentally. The FINFLO software, developed at Helsinki University of Technology, has been used in the flow solution, and the commercial IGG and Field view programs for the grid generation and post processing. The annular channel is discretized as a sector mesh. Calculation is performed with constant mass flow rate on six rotational speeds. The effect of turbulence is calculated using three turbulence models. The friction coefficient and velocity factor are attained via total friction power. The first part of experimental section consists of finding the proper sensors and calibrating them in a straight pipe. After preliminary tests, a RdF-sensor is glued on the walls of stator and rotor surfaces. Telemetry is needed to be able to measure the heat transfer coefficients at the rotor. The mean heat transfer coefficients are measured in a test machine on four cooling air mass flow rates at a wide Couette Reynolds number range. The calculated values concerning the friction and heat transfer coefficients are compared with measured and semi-empirical data. Heat is transferred from the hotter stator and rotor surfaces to the coolerair flow in the air gap, not from the rotor to the stator via the air gap, althought the stator temperature is lower than the rotor temperature. The calculatedfriction coefficients fits well with the semi-empirical equations and precedingmeasurements. On constant mass flow rate the rotor heat transfer coefficient attains a saturation point at a higher rotational speed, while the heat transfer coefficient of the stator grows uniformly. The magnitudes of the heat transfer coefficients are almost constant with different turbulence models. The calibrationof sensors in a straight pipe is only an advisory step in the selection process. Telemetry is tested in the pipe conditions and compared to the same measurements with a plain sensor. The magnitudes of the measured data and the data from the semi-empirical equation are higher for the heat transfer coefficients than thenumerical data considered on the velocity range. Friction and heat transfer coefficients are presented in a large velocity range in the report. The goals are reached acceptably using numerical and experimental research. The next challenge is to achieve results for grooved stator-rotor combinations. The work contains also results for an air gap with a grooved stator with 36 slots. The velocity field by the numerical method does not match in every respect the estimated flow mode. The absence of secondary Taylor vortices is evident when using time averagednumerical simulation.

Formation and Control of Trace Metal Emissions in Co-Firing of Biomass, Peat, and Wastes in Fluidised Bed Combustors

Environmentally harmful consequences of fossil fuel utilisation andthe landfilling of wastes have increased the interest among the energy producers to consider the use of alternative fuels like wood fuels and Refuse-Derived Fuels, RDFs. The fluidised bed technology that allows the flexible use of a variety of different fuels is commonly used at small- and medium-sized power plants ofmunicipalities and industry in Finland. Since there is only one mass-burn plantcurrently in operation in the country and no intention to build new ones, the co-firing of pre-processed wastes in fluidised bed boilers has become the most generally applied waste-to-energy concept in Finland. The recently validated EU Directive on Incineration of Wastes aims to mitigate environmentally harmful pollutants of waste incineration and co-incineration of wastes with conventional fuels. Apart from gaseous flue gas pollutants and dust, the emissions of toxic tracemetals are limited. The implementation of the Directive's restrictions in the Finnish legislation is assumed to limit the co-firing of waste fuels, due to the insufficient reduction of the regulated air pollutants in the existing flue gas cleaning devices. Trace metals emission formation and reduction in the ESP, the condensing wet scrubber, the fabric filter, and the humidification reactor were studied, experimentally, in full- and pilot-scale combustors utilising the bubbling fluidised bed technology, and, theoretically, by means of reactor model calculations. The core of the model is a thermodynamic equilibrium analysis. The experiments were carried out with wood chips, sawdust, and peat, and their refuse-derived fuel, RDF, blends. In all, ten different fuels or fuel blends were tested. Relatively high concentrations of trace metals in RDFs compared to the concentrations of these metals in wood fuels increased the trace metal concentrations in the flue gas after the boiler ten- to hundred-folds, when RDF was co-fired with sawdust in a full-scale BFB boiler. In the case of peat, lesser increase in trace metal concentrations was observed, due to the higher initial trace metal concentrations of peat compared to sawdust. Despite the high removal rate of most of the trace metals in the ESP, the Directive emission limits for trace metals were exceeded in each of the RDF co-firing tests. The dominat trace metals in fluegas after the ESP were Cu, Pb and Mn. In the condensing wet scrubber, the flue gas trace metal emissions were reduced below the Directive emission limits, whenRDF pellet was used as a co-firing fuel together with sawdust and peat. High chlorine content of the RDFs enhanced the mercuric chloride formation and hence the mercury removal in the ESP and scrubber. Mercury emissions were lower than theDirective emission limit for total Hg, 0.05 mg/Nm3, in all full-scale co-firingtests already in the flue gas after the ESP. The pilot-scale experiments with aBFB combustor equipped with a fabric filter revealed that the fabric filter alone is able to reduce the trace metal concentrations, including mercury, in the flue gas during the RDF co-firing approximately to the same level as they are during the wood chip firing. Lower trace metal emissions than the Directive limits were easily reached even with a 40% thermal share of RDF co-firing with sawdust.Enrichment of trace metals in the submicron fly ash particle fraction because of RDF co-firing was not observed in the test runs where sawdust was used as the main fuel. The combustion of RDF pellets with peat caused an enrichment of As, Cd, Co, Pb, Sb, and V in the submicron particle mode. Accumulation and release oftrace metals in the bed material was examined by means of a bed material analysis, mass balance calculations and a reactor model. Lead, zinc and copper were found to have a tendency to be accumulated in the bed material but also to have a tendency to be released from the bed material into the combustion gases, if the combustion conditions were changed. The concentration of the trace metal in the combustion gases of the bubbling fluidised bed boiler was found to be a summary of trace metal fluxes from three main sources. They were (1) the trace metal flux from the burning fuel particle (2) the trace metal flux from the ash in the bed, and (3) the trace metal flux from the active alkali metal layer on the sand (and ash) particles in the bed. The amount of chlorine in the system, the combustion temperature, the fuel ash composition and the saturation state of the bed material in regard to trace metals were discovered to be key factors affecting therelease process. During the co-firing of waste fuels with variable amounts of e.g. ash and chlorine, it is extremely important to consider the possible ongoingaccumulation and/or release of the trace metals in the bed, when determining the flue gas trace metal emissions. If the state of the combustion process in regard to trace metals accumulation and/or release in the bed material is not known,it may happen that emissions from the bed material rather than the combustion of the fuel in question are measured and reported.

Artificially Intelligent and Adaptive Methods for Prediction and Analysis of Superheater Fireside Corrosion in Fluidized Bed Boilers

Superheater corrosion causes vast annual losses for the power companies. With a reliable corrosion prediction method, the plants can be designed accordingly, and knowledge of fuel selection and determination of process conditions may be utilized to minimize superheater corrosion. Growing interest to use recycled fuels creates additional demands for the prediction of corrosion potential. Models depending on corrosion theories will fail, if relations between the inputs and the output are poorly known. A prediction model based on fuzzy logic and an artificial neural network is able to improve its performance as the amount of data increases. The corrosion rate of a superheater material can most reliably be detected with a test done in a test combustor or in a commercial boiler. The steel samples can be located in a special, temperature-controlled probe, and exposed to the corrosive environment for a desired time. These tests give information about the average corrosion potential in that environment. Samples may also be cut from superheaters during shutdowns. The analysis ofsamples taken from probes or superheaters after exposure to corrosive environment is a demanding task: if the corrosive contaminants can be reliably analyzed, the corrosion chemistry can be determined, and an estimate of the material lifetime can be given. In cases where the reason for corrosion is not clear, the determination of the corrosion chemistry and the lifetime estimation is more demanding. In order to provide a laboratory tool for the analysis and prediction, a newapproach was chosen. During this study, the following tools were generated: · Amodel for the prediction of superheater fireside corrosion, based on fuzzy logic and an artificial neural network, build upon a corrosion database developed offuel and bed material analyses, and measured corrosion data. The developed model predicts superheater corrosion with high accuracy at the early stages of a project. · An adaptive corrosion analysis tool based on image analysis, constructedas an expert system. This system utilizes implementation of user-defined algorithms, which allows the development of an artificially intelligent system for thetask. According to the results of the analyses, several new rules were developed for the determination of the degree and type of corrosion. By combining these two tools, a user-friendly expert system for the prediction and analyses of superheater fireside corrosion was developed. This tool may also be used for the minimization of corrosion risks by the design of fluidized bed boilers.

On Modelling, System Identification and Control of Servo-Systems with a Flexible Load

The present study was done with two different servo-systems. In the first system, a servo-hydraulic system was identified and then controlled by a fuzzy gainscheduling controller. The second servo-system, an electro-magnetic linear motor in suppressing the mechanical vibration and position tracking of a reference model are studied by using a neural network and an adaptive backstepping controller respectively. Followings are some descriptions of research methods. Electro Hydraulic Servo Systems (EHSS) are commonly used in industry. These kinds of systems are nonlinearin nature and their dynamic equations have several unknown parameters.System identification is a prerequisite to analysis of a dynamic system. One of the most promising novel evolutionary algorithms is the Differential Evolution (DE) for solving global optimization problems. In the study, the DE algorithm is proposed for handling nonlinear constraint functionswith boundary limits of variables to find the best parameters of a servo-hydraulic system with flexible load. The DE guarantees fast speed convergence and accurate solutions regardless the initial conditions of parameters. The control of hydraulic servo-systems has been the focus ofintense research over the past decades. These kinds of systems are nonlinear in nature and generally difficult to control. Since changing system parameters using the same gains will cause overshoot or even loss of system stability. The highly non-linear behaviour of these devices makes them ideal subjects for applying different types of sophisticated controllers. The study is concerned with a second order model reference to positioning control of a flexible load servo-hydraulic system using fuzzy gainscheduling. In the present research, to compensate the lack of dampingin a hydraulic system, an acceleration feedback was used. To compare the results, a pcontroller with feed-forward acceleration and different gains in extension and retraction is used. The design procedure for the controller and experimental results are discussed. The results suggest that using the fuzzy gain-scheduling controller decrease the error of position reference tracking. The second part of research was done on a PermanentMagnet Linear Synchronous Motor (PMLSM). In this study, a recurrent neural network compensator for suppressing mechanical vibration in PMLSM with a flexible load is studied. The linear motor is controlled by a conventional PI velocity controller, and the vibration of the flexible mechanism is suppressed by using a hybrid recurrent neural network. The differential evolution strategy and Kalman filter method are used to avoid the local minimum problem, and estimate the states of system respectively. The proposed control method is firstly designed by using non-linear simulation model built in Matlab Simulink and then implemented in practical test rig. The proposed method works satisfactorily and suppresses the vibration successfully. In the last part of research, a nonlinear load control method is developed and implemented for a PMLSM with a flexible load. The purpose of the controller is to track a flexible load to the desired position reference as fast as possible and without awkward oscillation. The control method is based on an adaptive backstepping algorithm whose stability is ensured by the Lyapunov stability theorem. The states of the system needed in the controller are estimated by using the Kalman filter. The proposed controller is implemented and tested in a linear motor test drive and responses are presented.

Pumpunvalitsimet integroidussa simulointiympäristössä

Työssä on tutkittu pumpun valintaa integroidussa simulointiympäristössä. Tutkimuksen avulla on tarkoitus kehittää tieto- ja malligallerian (Galleria) infrastuktuuria ja käytössä olevia työvälineitä siihen suuntaan, että ulkoisten valitsinkomponenttien implementoiminen Gallerian tietokantaan olisi lähitulevaisuudessa helppoa ja nopeaa. Prosessi-integraation tieto- ja malligalleria on infrastruktuurimäärittely ja työvälineistö prosessikomponenttien ja osaprosessien simulointiin tarvittavien malli- ja parametritietojen kirjastoimiseksi internetpohjaiseen tietokantaan, josta ne ovat simulointiohjelmien käyttäjien ja muiden prosessisuunnittelijoiden helposti saatavilla. Tutkimuksen kirjallisessa osassa on keskitytty tutkimaan pumpun valinnan etenemistä ja valintaan vaikuttavia tekijöitä prosessisuunnittelijan näkökulmasta. Tutkimuksen soveltavassa osassa luotiin pumpunvalitsin ja sitä testattiiin Galleria- ympäristöä vastaavassa kehitysympäristössä. Pumpunvalitsimen kehittämisessä on käytetty apuna laitevalmistajalta saatua prosessikomponenttitietoa. Pumpunvalitsimen toteutus perustuu pumpun hydrauliseen valintaan ja esimerkkitapauksena käytettiin keskipakopumppua

Euron käyttöönoton hallinta keskisuuressa yrityksessä

Työn tavoitteena oli laatia euron käyttöönottosuunnitelma. Ensin selvitettiin euron syntyvaiheet ja yhteisen valuutan käsittelysäännöt. Sen jälkeen käydään läpi eräs käyttökelpoinen suunnitelma euron käyttöönottamiseksi, johon kuuluu euron käyttöönoton and speed up the implementation of external selection components. Model and Parametrisation Gallery for Process Integration is specification of an infrastructure and a set of tools which are built for storing process component and model library data into an internet based database from where it can be easily used by simulator users and other process designers. This work consists of two parts. In the literature survey pump selection and the factors that affects selection particularly on process designers point of view are studied. In the applied part a pump selector was created and tested in the test environment which is comparable to Gallery environment. This was done to ease the deployment of the selector to the actual working environment. Process component data of a manufacturer was used on the development of the pump selector. The execution of the selector is based on the hydraulic selection of pumps. Centrifugal pump was used as an example case.

Sähköisen liiketoiminnan vaikutukset suurten energiayhtiöiden myyntitoimintaan

Työn tavoitteena oli selvittää tutkimukseen valittujen energiayhtiöiden TXU Europen, Centrican, RWE:n, Vattenfallin, Royal Dutch/Shellin ja Statoilin sähköisen liiketoiminnan tavoitteita ja tarkoitusta. Ensin käytiin läpi sähköisen liiketoiminnan käsitteitä ja Internetin merkitystä. Seuraavaksi selvitettiin energiamarkkinoilla tapahtuneita muutoksia, joiden puitteissa sähköinen liiketoiminta energiamarkkinoilla tulisi ymmärtää. Lopuksi energiayhtiöiden sähköiset palvelut analysoitiin perusteellisesti tutkimuksessa rakennettua viitekehystä apuna käyttämällä. Tutkimus perustuu täysin julkiseen informaatioon.Tällä hetkellä koko energianmyyntiprosessin suorittaminen alusta loppuun on energiayhtiöiden verkkosivuilla mahdollista. Sivut ovat kehittyneet pelkistä kotisivuista tarjous-, sopimus- ja laskutusprosessitoiminnot sisältäviksi sähköisiksi kauppapaikoiksi. Palveluita on myös vähitellen alettu integroimaan yritysten operatiivisiin järjestelmiin ja räätälöityjen palveluiden kehitys korostuu tulevaisuudessa. Asiakkaan itsepalvelumahdollisuudet lisääntyvät. Lisäarvoa tuovia palveluita kehitetään asiakassuhdetta vähitellen uusilla tuotteilla vahvistaen, laajaan energiayhtiöpohjaan perustuen tai viemällä useita uusia energiaan liittyviä tuotteita ja myös uusia energiatuotteita kerralla markkinoille. Yhteistyön merkitys tuotepakettien kehittämisessä korostuu.

Sinkkirikasteen suoraliuotusreaktorin kehittäminen

Hydrometallurgiseen sinkinvalmistusprosessiin kuuluu yleensä pasutus, liuotus, puhdistus ja elektrolyysi. Sinkkirikasteen suoraliuotusmenetelmässä sinkkisulfidi liuotetaan suoraan ilman pasutusta. Suoraliuotusprosessissa prosessiliuokseen lietettyä sinkkisulfidia syötetään liuotusreaktoriin, jossa on liuottimena rikkihappoa. Sinkkisulfidi reagoi ferrisulfaatin kanssa muodostaen sinkkisulfaattia ja ferrosulfaattia, ja samalla rikki hapettuu alkuainerikiksi. Ferro-ionit hapetetaan takaisin ferri-muotoon syöttämällä reaktoriin happea. Tämän työn tarkoituksena oli löytää uudentyyppinen, edullisempi reaktori sinkkirikasteen suoraliuotukseen. Suunnittelussa pyrittiin kehittämään mahdollisimman monipuolinen koereaktori, jota voidaan hyväksikäyttää useiden suoraliuotuksen ilmiöiden, esimerkiksi hapen liukenemisen, tutkimiseen. Reaktori mitoitettiin pilot-laitteiston kokoiseksi. Valmiilla koelaitteistolla tehtiin lyhyt sarja kokeita ja jo niiden perusteella pystyi havaitsemaan reaktorin toimivan hyvin. Kokeiden päätarkoituksena oli testata laitteiston toimivuutta ja soveltuvuutta sinkkirikasteen liuotukseen. Työhön kuului myös kehitetyllä reaktorilla myöhemmin suoritettavan koetoiminnan suunnittelu.

Puhe IP-verkossa operaattorin näkökulmasta

Tässä diplomityössä tutkittiin operaattorin IP-verkossa toteutettavia puhepalveluita. Tutkimus perustui käytännön tarpeeseen. VoIP-tekniikalla toteutetuista puheluista on nopeasti tullut vakavasti otettava haastaja perinteiselle piirikytkentäiselle puhelintekniikalle. IP-tekniikka mahdollistaa data-, puhe- sekä videopalvelujen integroimisen yhteen verkkoon. Lisäksi IP-verkko on edullinen, laajalle levinnyt ja tehokas. Nämä ominaisuudet tekevät siitä houkuttelevan vaihtoehdon puhepalvelujen alustaksi. Verkkojen yhdistyminen mahdollistaa uudentyyppisen kommunikointiympäristön, jossa voidaan käyttää monenlaisia sovelluksia ja apuvälineitä ihmisten välisen kommunikoinnin helpottamiseksi. Tähän työhön sisältyi testilaitteiston hankkiminen ja asentaminen. Laitteistolla oli pystyttävä toteuttamaan operaattorin VoIP-järjestelmä, jolla oli kyettävä toteuttamaan usealle yritykselle IP-vaihdepalvelut. Laitteistoa testattiin itse aiheutetuilla virhetilanteilla sekä koekäyttäjillä. Testauksessa selvitettiin järjestelmän soveltuvuutta operaattorin tuotantokäyttöön.