Minimization of the experimental workload for the prediction of pollutants propagation in rivers. Mathematical modelling and knowledge re-use

The present thesis in focused on the minimization of experimental efforts for the prediction of pollutant propagation in rivers by mathematical modelling and knowledge re-use. Mathematical modelling is based on the well known advection-dispersion equation, while the knowledge re-use approach employs the methods of case based reasoning, graphical analysis and text mining. The thesis contribution to the pollutant transport research field consists of: (1) analytical and numerical models for pollutant transport prediction; (2) two novel techniques which enable the use of variable parameters along rivers in analytical models; (3) models for the estimation of pollutant transport characteristic parameters (velocity, dispersion coefficient and nutrient transformation rates) as functions of water flow, channel characteristics and/or seasonality; (4) the graphical analysis method to be used for the identification of pollution sources along rivers; (5) a case based reasoning tool for the identification of crucial information related to the pollutant transport modelling; (6) and the application of a software tool for the reuse of information during pollutants transport modelling research. These support tools are applicable in the water quality research field and in practice as well, as they can be involved in multiple activities. The models are capable of predicting pollutant propagation along rivers in case of both ordinary pollution and accidents. They can also be applied for other similar rivers in modelling of pollutant transport in rivers with low availability of experimental data concerning concentration. This is because models for parameter estimation developed in the present thesis enable the calculation of transport characteristic parameters as functions of river hydraulic parameters and/or seasonality. The similarity between rivers is assessed using case based reasoning tools, and additional necessary information can be identified by using the software for the information reuse. Such systems represent support for users and open up possibilities for new modelling methods, monitoring facilities and for better river water quality management tools. They are useful also for the estimation of environmental impact of possible technological changes and can be applied in the pre-design stage or/and in the practical use of processes as well.

Timing of Capacity Change: Models for Capital Intensive Industry

The suitable timing of capacity investments is a remarkable issue especially in capital intensive industries. Despite its importance, fairly few studies have been published on the topic. In the present study models for the timing of capacity change in capital intensive industry are developed. The study considers mainly the optimal timing of single capacity changes. The review of earlier research describes connections between cost, capacity and timing literature, and empirical examples are used to describe the starting point of the study and to test the developed models. The study includes four models, which describe the timing question from different perspectives. The first model, which minimizes unit costs, has been built for capacity expansion and replacement situations. It is shown that the optimal timing of an investment can be presented with the capacity and cost advantage ratios. After the unit cost minimization model the view is extended to the direction of profit maximization. The second model states that early investments are preferable if the change of fixed costs is small compared to the change of the contribution margin. The third model is a numerical discounted cash flow model, which emphasizes the roles of start-up time, capacity utilization rate and value of waiting as drivers of the profitable timing of a project. The last model expands the view from project level to company level and connects the flexibility of assets and cost structures to the timing problem. The main results of the research are the solutions of the models and analysis or simulations done with the models. The relevance and applicability of the results are verified by evaluating the logic of the models and by numerical cases.

Työnantajan sivukulujen poiston vaikutus työllisyyteen

Tutkielman tavoitteena oli osoittaa minkälaisia vaikutuksia työnantajan sivukulujen poisto toisi työllisyyteen. Tutkielman empiirinen osio toteutettiin survey-tutkimuksella. Tämä toteutettiin postikyselyllä, jossa 810 Etelä-Karjalalaiselle yritykselle lähetettiin joulukuussa 2004 kyselylomake. Kyselyyn vastanneiden yritysten määrä oli 141 ja vastausprosentti oli 17. Vastanneiden yritysten toimialajakauma vastasi koko Etelä-Karjalan alueen yritysten toimialajakaumaa, jossa suurimpana toimialana oli eri palvelualan yritykset. Tutkielma eroaa aikaisemminista työllisyyden parantamiseksi esitetyistä malleista. Ensimmäineneroavaisuus on sivukulujen poistaminen yrityksiltä kokonaan eikä vain muutamilla prosenttiyksiköillä. Toinen eroavaisuus on sivukulujen poiston kohdistamisessavain niille yrityksille, joilla työllistävyys kasvaa merkittävästi. Näiden tarkoituksena on maksimoida työllisyysvaikutukset ja vaikuttaa aiheutuneiden kustannusten minimointiin tai kustannusten korvaantumiseen täysimääräisesti. Asetetut tavoitteet voidaan saavuttaa kohdistamalla sivukulujen poisto vain niihin yrityksiin, jotka työllistävät alle 5 henkilöä. Näiden yritysten kohdalla mahdollistuvauusien työntekijöiden määrä nousee keskimäärin 36 prosentilla. Tämä merkitsee laskelmien mukaan sitä, että sivululujen poiston aiheuttama sosiaalivakuutusmaksujen väheneminen korvaantuu vanhojen ja uusien työntekijöiden maksamilla tuloveroilla ja vähentyvillä työttömyyskorvauksilla. Uusien työpaikkojen kasvu merkitseeEtelä-Karjalan työttömyysprosentin laskua yli 4 prosenttiyksiköllä.

Reduction of Greenhouse Gas Emissions in North-West Russia - Finnish Business Opportunities

Tutkimus suomalaisten yritysten liiketoimintamahdollisuuksista hiilidoksidipäästöjen vähentämisen parissa Luoteis-Venäjällä.

Conflict-based Method for Conceptual Process Synthesis

The changing business environment demands that chemical industrial processes be designed such that they enable the attainment of multi-objective requirements and the enhancement of innovativedesign activities. The requirements and key issues for conceptual process synthesis have changed and are no longer those of conventional process design; there is an increased emphasis on innovative research to develop new concepts, novel techniques and processes. A central issue, how to enhance the creativity of the design process, requires further research into methodologies. The thesis presentsa conflict-based methodology for conceptual process synthesis. The motivation of the work is to support decision-making in design and synthesis and to enhance the creativity of design activities. It deals with the multi-objective requirements and combinatorially complex nature of process synthesis. The work is carriedout based on a new concept and design paradigm adapted from Theory of InventiveProblem Solving methodology (TRIZ). TRIZ is claimed to be a `systematic creativity' framework thanks to its knowledge based and evolutionary-directed nature. The conflict concept, when applied to process synthesis, throws new lights on design problems and activities. The conflict model is proposed as a way of describing design problems and handling design information. The design tasks are represented as groups of conflicts and conflict table is built as the design tool. The general design paradigm is formulated to handle conflicts in both the early and detailed design stages. The methodology developed reflects the conflict nature of process design and synthesis. The method is implemented and verified through case studies of distillation system design, reactor/separator network design and waste minimization. Handling the various levels of conflicts evolve possible design alternatives in a systematic procedure which consists of establishing an efficient and compact solution space for the detailed design stage. The approach also provides the information to bridge the gap between the application of qualitative knowledge in the early stage and quantitative techniques in the detailed design stage. Enhancement of creativity is realized through the better understanding of the design problems gained from the conflict concept and in the improvement in engineering design practice via the systematic nature of the approach.

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.

Direct torque control of permanent magnet synchronous machines - analysis and implementation

Thedirect torque control (DTC) has become an accepted vector control method besidethe current vector control. The DTC was first applied to asynchronous machines,and has later been applied also to synchronous machines. This thesis analyses the application of the DTC to permanent magnet synchronous machines (PMSM). In order to take the full advantage of the DTC, the PMSM has to be properly dimensioned. Therefore the effect of the motor parameters is analysed taking the control principle into account. Based on the analysis, a parameter selection procedure is presented. The analysis and the selection procedure utilize nonlinear optimization methods. The key element of a direct torque controlled drive is the estimation of the stator flux linkage. Different estimation methods - a combination of current and voltage models and improved integration methods - are analysed. The effect of an incorrect measured rotor angle in the current model is analysed andan error detection and compensation method is presented. The dynamic performance of an earlier presented sensorless flux estimation method is made better by improving the dynamic performance of the low-pass filter used and by adapting the correction of the flux linkage to torque changes. A method for the estimation ofthe initial angle of the rotor is presented. The method is based on measuring the inductance of the machine in several directions and fitting the measurements into a model. The model is nonlinear with respect to the rotor angle and therefore a nonlinear least squares optimization method is needed in the procedure. A commonly used current vector control scheme is the minimum current control. In the DTC the stator flux linkage reference is usually kept constant. Achieving the minimum current requires the control of the reference. An on-line method to perform the minimization of the current by controlling the stator flux linkage reference is presented. Also, the control of the reference above the base speed is considered. A new estimation flux linkage is introduced for the estimation of the parameters of the machine model. In order to utilize the flux linkage estimates in off-line parameter estimation, the integration methods are improved. An adaptive correction is used in the same way as in the estimation of the controller stator flux linkage. The presented parameter estimation methods are then used in aself-commissioning scheme. The proposed methods are tested with a laboratory drive, which consists of a commercial inverter hardware with a modified software and several prototype PMSMs.

Jätteen määrän vähentäminen ja jätteenkäsittelymahdollisuuksien selvittäminen pinnoitetehtaassa

EU:n mukanaan tuomat uudet vaatimukset jätteenpoltolle aiheuttavat suuria muutoksia Dynea Overlays Oy:n jätteen käsittelylle. Samalla tehdasalueella tapahtuva jätteenpoltto päättyy todennäköisesti vuoden 2005 lopulla. Tästä syystä tehtaalla syntyville jätteille haettiin uusia hävitysreittejä. Jokaiselle jätejakeelle löydettiin uusi hävitysvaihtoehto, jotka pääosin ovat jätteen hyödyntämistä energiana. Pinnoitejätteet, kovetetut hartsit ja kuitujäte hyödynnetään energiana, tyhjät kertakäyttökontit joko otetaan uudelleenkäyttöön tai toimitetaan purettuina metallin- ja muovinkeräykseen. Työn toinen tavoite oli jätteen määrän vähentäminen. Jätteen määrää vähentämällä saadaan alennettua jätteenkäsittelykustannuksia sekä parannettua saantoa. Saanto on mittari, jota seurataan Dynean kaikilla pinnoitetehtailla ympäri maailmaa. Yrityksen johto on asettanut tavoitteeksi nostaa saannon vuoden 2003 tasolta 90 % tasolle 93 % vuoden 2004 loppuun mennessä. Jo vuoden 2004 ensimmäisinä kuukausina saanto näyttää parantuneen tavoitetasolle asiaan kiinnitetyn huomion ja tarkentuneen raportoinnin seurauksena.

SB-lateksitehtaan päästöjen minimointi

Diplomityön tavoitteena oli löytää soveltuvimmat parhaaseen käytettävissä olevaan tekniikkaan perustuvat menetelmät SB-lateksitehtaan päästöjen käsittelemiseksi. Kirjallisuuslähteinä käytettiin Euroopan komission julkaisemia toimialakohtaisia BAT-julkaisuja. Lisäksi hyödynnettiin kemianteollisuudessa jo käytössä olevien menetelmien kokemusperäistä tietoa. Kokeellinen osan pohjaksi kartoitettiin merkittävät päästölähteet: kiinteät, nestemäiset ja kaasumaiset päästöt. Päästömittaukset olivat kvantitatiivisia, mutta mittauksissa kerättiin myös kvalitatiivista tietoa. Kirjallisen ja kokemusperäisen tiedon sekä päästöjen mittaustulosten perusteella valittiin soveltuvimmat päästöjenkäsittelyvaihtoehdot. Kiinteiden päästöjen määrään vaikuttaa eniten lateksin suodatusmenetelmän valinta. Nestemäisten päästöjen uudelleenkäyttö on tehokkain tapa minimoida päästöjä. Tehokkain tapa käsitellä orgaanisia jätevesiä on kolonnistrippaus. Lateksipitoisille jätevesille soveltuvin menetelmä on membraanitekniikka. Kaasuseospäästöille soveltuvin käsittelymenetelmä on terminen kammiopoltto. Yhden kemikaalin kaasupäästöjen käsittelyssä menetelmät perustuvat kondensointiin, paikallisiin suodattimiin ja kaasujen takaisinkierrätykseen riippuen kemikaalin ominaisuuksista.

Pienten päivittäistavarakauppojen energiatalouden parantaminen

Työn tavoitteena oli löytää keinoja, joiden avulla kylmälaite- ja ilmanvaihtojärjestelmien toimintaa voitaisiin kehittää ja myymälöiden energiataloutta parantaa. Johtopäätökset sekä jatkotoimenpide-ehdotukset tehtiin koekohteista saatujen mittaustulosten sekä laskennallisten tavoitekulutusten perusteella. Tutkimus koski alle 400 m2 päivittäistavarakauppoja, joita Suomessa oli vuoden 2002 lopussa 3 011 kappaletta. Tutkimuksessa koekohteina toimineet kaksi Siwa-myymälää kuuluvat yli 450 Suomessa toimivan Siwan myymäläketjuun. Koekohteista saatujen tutkimustulosten pohjalta energiansäästötoimenpiteitä voidaan kohdistaa myös muihin Siwa-myymälöihin, jolloin energiansäästöt kasvavat huomattaviksi. Koekohteissa kylmälaitteiden osuus sähköenergiankulutuksesta oli merkittävin. Lämmönkulutuksissa suurten erojen syynä olivat koekohteiden erilaiset lauhdelämmöntalteenottojärjestelmät. Tehokkaalla lauhdelämmön talteenotolla onkin suuri merkitys myymälöiden energiatalouteen. Tulevaisuudessa elektronisten ohjausjärjestelmien käyttö tulee lisääntymään pienissä päivittäistavarakaupoissa. Ohjausjärjestelmällä saavutettavia etuja ovat energiankulutuksen minimointi, lämpötilojen tarkempi säätö- ja valvonta, lämpötilojen rekisteröinti ja kaukovalvonta. Muita myymälän energiatalouden kannalta tärkeitä tekijöitä ovat lauhdelämmön talteenotto, määräajoin tapahtuvat laitehuollot, kylmäntarpeen minimointi, energiatehokkaiden kylmäkalusteiden käyttö sekä kylmäkalusteet huomioiva myymäläsuunnittelu.

Assessment of Environmental Impacts of Power Generation

Through indisputable evidence of climate change and its link to the greenhouse gas emissions comes the necessity for change in energy production infrastructure during the coming decades. Through political conventions and restrictions energy industry is pushed toward using bigger share of renewable energy sources as energy supply. In addition to climate change, sustainable energy supply is another major issue for future development plans, but neither of these should come with unbearable price. All the power production types have environmental effects as well as strengths and weaknesses. Although each change comes with a price, right track in minimising the environmental impacts and energy supply security can be found by combining all possible low-carbon technologies and by improving energy efficiency in all sectors, for creating a new power production infrastructure of tolerable energy price and of minor environmental effects. GEMIS-Global Emission Model for Integrated Systems is a life-cycle analysis program which was used in this thesis to make indicative energy models for Finland’s future energy supply. Results indicate that the energy supply must comprise both high capacity nuclear power as well as large variation of renewable energy sources for minimization of all environmental effects and keeping energy price reasonable.

Mechanical Design of Hydraulic Vise

The general task of clamping devise is to connect the parts to the machining centers so that the work piece could be fixed on its position during the whole machining process. Additionally, the work piece should be clamped easily and rapidly by the machine users. The purpose of this Master’s thesis project was to develop a product design and find out the dimensioning of a hydraulic vise system for Astex Engineering OY, which was taking care of the general principles of product design and development during the design process. Throughout the process, the needs of manufacturing and assembling were taken into consideration for the machinability and minimization of the cost of manufacturing. The most critical component of the clamping devise was modeled by FEM for the issue of strength requirements. This 3D model was created with Solidworks and FEM-analysis was done with Cosmos software. As the result of this design work, a prototype of the hydraulic vise was manufactured for Astex Engineering OY and the practical test.

Utilization of a Time Domain Simulator in the Technical and Economic Analysis of a Wind Turbine Electric Drive Train

The amount of installed wind power has been growing exponentially during the past ten years. As wind turbines have become a significant source of electrical energy, the interactions between the turbines and the electric power network need to be studied more thoroughly than before. Especially, the behavior of the turbines in fault situations is of prime importance; simply disconnecting all wind turbines from the network during a voltage drop is no longer acceptable, since this would contribute to a total network collapse. These requirements have been a contributor to the increased role of simulations in the study and design of the electric drive train of a wind turbine. When planning a wind power investment, the selection of the site and the turbine are crucial for the economic feasibility of the installation. Economic feasibility, on the other hand, is the factor that determines whether or not investment in wind power will continue, contributing to green electricity production and reduction of emissions. In the selection of the installation site and the turbine (siting and site matching), the properties of the electric drive train of the planned turbine have so far been generally not been taken into account. Additionally, although the loss minimization of some of the individual components of the drive train has been studied, the drive train as a whole has received less attention. Furthermore, as a wind turbine will typically operate at a power level lower than the nominal most of the time, efficiency analysis in the nominal operating point is not sufficient. This doctoral dissertation attempts to combine the two aforementioned areas of interest by studying the applicability of time domain simulations in the analysis of the economicfeasibility of a wind turbine. The utilization of a general-purpose time domain simulator, otherwise applied to the study of network interactions and control systems, in the economic analysis of the wind energy conversion system is studied. The main benefits of the simulation-based method over traditional methods based on analytic calculation of losses include the ability to reuse and recombine existing models, the ability to analyze interactions between the components and subsystems in the electric drive train (something which is impossible when considering different subsystems as independent blocks, as is commonly done in theanalytical calculation of efficiencies), the ability to analyze in a rather straightforward manner the effect of selections other than physical components, for example control algorithms, and the ability to verify assumptions of the effects of a particular design change on the efficiency of the whole system. Based on the work, it can be concluded that differences between two configurations can be seen in the economic performance with only minor modifications to the simulation models used in the network interaction and control method study. This eliminates the need ofdeveloping analytic expressions for losses and enables the study of the system as a whole instead of modeling it as series connection of independent blocks with no lossinterdependencies. Three example cases (site matching, component selection, control principle selection) are provided to illustrate the usage of the approach and analyze its performance.

Hitsauksen aiheuttamat muodonmuutokset ja niiden hallinta alumiiniveneiden rakenteissa

Alumiiniveneissä hitsauksen aiheuttamat muodonmuutokset ovat usein erittäin haitallisia, koska niiden aiheuttamat mittamuutokset ja ulkonäölliset haitat alentavat tuotteen laatua sekä arvoa. Monissa tapauksissa myös hitsausliitoksen suorituskyky heikentyy ja lisäksi hitsausmuodonmuutokset voivat aiheuttaa toiminnallisia ongelmia alumiiniveneiden runkorakenteisiin. Tästä johtuen hitsausmuodonmuutosten hallinta ja minimointi ovat erityisen tärkeitä tekijöitä pyrittäessä parantamaan alumiiniveneiden laatua ja kustannustehokkuutta sekä kasvattamaan alumiinivenealan kilpailukykyä. Tässä diplomityössä tutkittiin robotisoidun kaasukaarihitsauksen aiheuttamia muodonmuutoksia sekä niiden hallintaa alumiinista valmistettujen työ- ja huviveneiden runkorakenteissa. Työssä perehdyttiin nykyaikaiseen alumiinivenevalmistukseen sekä hitsattujen rakenteiden yleisiin lujuusopin teorioihin ja käyttäytymismalleihin. Alumiinin hitsausmuodonmuutosten tutkimuksissa suoritettiin käytännön hitsauskokeita, joiden kohteina olivat alumiiniveneissä käytetyt rakenneratkaisut ja liitostyypit. Työn tavoitteena oli määrittää alumiinin hitsauksessa syntyviin muodonmuutoksiin keskeisesti vaikuttavia tekijöitä ja parametreja. Tutkimustulosten perusteella pyrittiin esittämään ratkaisuja alumiiniveneiden rakenteisiin aiheutuvien hitsausmuodonmuutosten vähentämiseksi ja hallitsemiseksi. Alumiinirakenteissa hitsausmuodonmuutokset ovat hyvin tapauskohtaisia, koska usein niiden syntyminen määräytyy monen tekijän yhteisvaikutuksesta. Teräsrakenteille käytetyt yleiset analyyttiset laskentakaavat ja käyttäytymismallit eivät sovellu suoraan alumiinirakenteille, mikä johtuu alumiinin erilaisista materiaaliominaisuuksista ja käyttäytymisestä hitsauksen aikana. Tulevaisuudessa empiiristen koejärjestelyiden ja analyyttisten mallien lisäksi sovellettavan numeerisen elementtimenetelmän avulla voidaan parantaa alumiinin hitsauksessa aiheutuvien muodonmuutosten kokonaisvaltaista hallintaa.