Fluid flow and dispersion predictions in porous media by utilizing advanced numerical methods

Diplomityön tavoitteena oli tarkastella numeerisen virtauslaskennan avulla virtaukseen liittyviä ilmiöitä ja kaasun dispersiota. Diplomityön sisältö on jaettu viiteen osaan; johdantoon, teoriaan, katsaukseen virtauksen mallinnukseen huokoisessa materiaalissa liittyviin tutkimusselvityksiin, numeeriseen mallinnukseen sekä tulosten esittämiseen ja johtopäätöksiin. Diplomityön alussa kiinnitettiin huomiota erilaisiin kokeellisiin, numeerisiin ja teoreettisiin mallinnusmenetelmiin, joilla voidaan mallintaa virtausta huokoisessa materiaalissa. Kirjallisuusosassa tehtiin katsaus aikaisemmin julkaistuihin puoliempiirisiin ja empiirisiin tutkimusselvityksiin, jotka liittyvät huokoisen materiaalin aiheuttamaan painehäviöön. Numeerisessa virtauslaskenta osassa rakennettiin ja esitettiin huokoista materiaalia kuvaavat numeeriset mallit käyttäen kaupallista FLUENT -ohjelmistoa. Työn lopussa arvioitiin teorian, numeerisen virtauslaskennan ja kokeellisten tutkimusselvitysten tuloksia. Kolmiulotteisen huokoisen materiaalinnumeerisessa mallinnuksesta saadut tulokset vaikuttivat lupaavilta. Näiden tulosten perusteella tehtiin suosituksia ajatellen tulevaa virtauksen mallinnusta huokoisessa materiaalissa. Osa tässä diplomityössä esitetyistä tuloksista tullaan esittämään 55. Kanadan Kemiantekniikan konferenssissa Torontossa 1619 Lokakuussa 2005. ASME :n kansainvälisessä tekniikan alan julkaisussa. Työ on hyväksytty esitettäväksi esitettäväksi laskennallisen virtausmekaniikan (CFD) aihealueessa 'Peruskäsitteet'. Lisäksi työn yksityiskohtaiset tulokset tullaan lähettämään myös CES:n julkaisuun.

Selective catalytic reduction of nitrogen oxides with ammonia in forced unsteady state reactors - Case based reasoning and mathematical model simulation reasoning

The application of forced unsteady-state reactors in case of selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3) is sustained by the fact that favorable temperature and composition distributions which cannot be achieved in any steady-state regime can be obtained by means of unsteady-state operations. In a normal way of operation the low exothermicity of the selective catalytic reduction (SCR) reaction (usually carried out in the range of 280-350°C) is not enough to maintain by itself the chemical reaction. A normal mode of operation usually requires supply of supplementary heat increasing in this way the overall process operation cost. Through forced unsteady-state operation, the main advantage that can be obtained when exothermic reactions take place is the possibility of trapping, beside the ammonia, the moving heat wave inside the catalytic bed. The unsteady state-operation enables the exploitation of the thermal storage capacity of the catalyticbed. The catalytic bed acts as a regenerative heat exchanger allowing auto-thermal behaviour when the adiabatic temperature rise is low. Finding the optimum reactor configuration, employing the most suitable operation model and identifying the reactor behavior are highly important steps in order to configure a proper device for industrial applications. The Reverse Flow Reactor (RFR) - a forced unsteady state reactor - corresponds to the above mentioned characteristics and may be employed as an efficient device for the treatment of dilute pollutant mixtures. As a main disadvantage, beside its advantages, the RFR presents the 'wash out' phenomena. This phenomenon represents emissions of unconverted reactants at every switch of the flow direction. As a consequence our attention was focused on finding an alternative reactor configuration for RFR which is not affected by the incontrollable emissions of unconverted reactants. In this respect the Reactor Network (RN) was investigated. Its configuration consists of several reactors connected in a closed sequence, simulating a moving bed by changing the reactants feeding position. In the RN the flow direction is maintained in the same way ensuring uniformcatalyst exploitation and in the same time the 'wash out' phenomena is annulated. The simulated moving bed (SMB) can operate in transient mode giving practically constant exit concentration and high conversion levels. The main advantage of the reactor network operation is emphasizedby the possibility to obtain auto-thermal behavior with nearly uniformcatalyst utilization. However, the reactor network presents only a small range of switching times which allow to reach and to maintain an ignited state. Even so a proper study of the complex behavior of the RN may give the necessary information to overcome all the difficulties that can appear in the RN operation. The unsteady-state reactors complexity arises from the fact that these reactor types are characterized by short contact times and complex interaction between heat and mass transportphenomena. Such complex interactions can give rise to a remarkable complex dynamic behavior characterized by a set of spatial-temporal patterns, chaotic changes in concentration and traveling waves of heat or chemical reactivity. The main efforts of the current research studies concern the improvement of contact modalities between reactants, the possibility of thermal wave storage inside the reactor and the improvement of the kinetic activity of the catalyst used. Paying attention to the above mentioned aspects is important when higher activity even at low feeding temperatures and low emissions of unconverted reactants are the main operation concerns. Also, the prediction of the reactor pseudo or steady-state performance (regarding the conversion, selectivity and thermal behavior) and the dynamicreactor response during exploitation are important aspects in finding the optimal control strategy for the forced unsteady state catalytic tubular reactors. The design of an adapted reactor requires knowledge about the influence of its operating conditions on the overall process performance and a precise evaluation of the operating parameters rage for which a sustained dynamic behavior is obtained. An apriori estimation of the system parameters result in diminution of the computational efforts. Usually the convergence of unsteady state reactor systems requires integration over hundreds of cycles depending on the initial guess of the parameter values. The investigation of various operation models and thermal transfer strategies give reliable means to obtain recuperative and regenerative devices which are capable to maintain an auto-thermal behavior in case of low exothermic reactions. In the present research work a gradual analysis of the SCR of NOx with ammonia process in forced unsteady-state reactors was realized. The investigation covers the presentationof the general problematic related to the effect of noxious emissions in the environment, the analysis of the suitable catalysts types for the process, the mathematical analysis approach for modeling and finding the system solutions and the experimental investigation of the device found to be more suitable for the present process. In order to gain information about the forced unsteady state reactor design, operation, important system parameters and their values, mathematical description, mathematicalmethod for solving systems of partial differential equations and other specific aspects, in a fast and easy way, and a case based reasoning (CBR) approach has been used. This approach, using the experience of past similarproblems and their adapted solutions, may provide a method for gaining informations and solutions for new problems related to the forced unsteady state reactors technology. As a consequence a CBR system was implemented and a corresponding tool was developed. Further on, grooving up the hypothesis of isothermal operation, the investigation by means of numerical simulation of the feasibility of the SCR of NOx with ammonia in the RFRand in the RN with variable feeding position was realized. The hypothesis of non-isothermal operation was taken into account because in our opinion ifa commercial catalyst is considered, is not possible to modify the chemical activity and its adsorptive capacity to improve the operation butis possible to change the operation regime. In order to identify the most suitable device for the unsteady state reduction of NOx with ammonia, considering the perspective of recuperative and regenerative devices, a comparative analysis of the above mentioned two devices performance was realized. The assumption of isothermal conditions in the beginningof the forced unsteadystate investigation allowed the simplification of the analysis enabling to focus on the impact of the conditions and mode of operation on the dynamic features caused by the trapping of one reactant in the reactor, without considering the impact of thermal effect on overall reactor performance. The non-isothermal system approach has been investigated in order to point out the important influence of the thermal effect on overall reactor performance, studying the possibility of RFR and RN utilization as recuperative and regenerative devices and the possibility of achieving a sustained auto-thermal behavior in case of lowexothermic reaction of SCR of NOx with ammonia and low temperature gasfeeding. Beside the influence of the thermal effect, the influence of the principal operating parameters, as switching time, inlet flow rate and initial catalyst temperature have been stressed. This analysis is important not only because it allows a comparison between the two devices and optimisation of the operation, but also the switching time is the main operating parameter. An appropriate choice of this parameter enables the fulfilment of the process constraints. The level of the conversions achieved, the more uniform temperature profiles, the uniformity ofcatalyst exploitation and the much simpler mode of operation imposed the RN as a much more suitable device for SCR of NOx with ammonia, in usual operation and also in the perspective of control strategy implementation. Theoretical simplified models have also been proposed in order to describe the forced unsteady state reactors performance and to estimate their internal temperature and concentration profiles. The general idea was to extend the study of catalytic reactor dynamics taking into account the perspectives that haven't been analyzed yet. The experimental investigation ofRN revealed a good agreement between the data obtained by model simulation and the ones obtained experimentally.

Design and Analysis of Forward Error Control Coding and Signaling for Guaranteeing QoS in Wireless Broadcast Systems

Broadcasting systems are networks where the transmission is received by several terminals. Generally broadcast receivers are passive devices in the network, meaning that they do not interact with the transmitter. Providing a certain Quality of Service (QoS) for the receivers in heterogeneous reception environment with no feedback is not an easy task. Forward error control coding can be used for protection against transmission errors to enhance the QoS for broadcast services. For good performance in terrestrial wireless networks, diversity should be utilized. The diversity is utilized by application of interleaving together with the forward error correction codes. In this dissertation the design and analysis of forward error control and control signalling for providing QoS in wireless broadcasting systems are studied. Control signaling is used in broadcasting networks to give the receiver necessary information on how to connect to the network itself and how to receive the services that are being transmitted. Usually control signalling is considered to be transmitted through a dedicated path in the systems. Therefore, the relationship of the signaling and service data paths should be considered early in the design phase. Modeling and simulations are used in the case studies of this dissertation to study this relationship. This dissertation begins with a survey on the broadcasting environment and mechanisms for providing QoS therein. Then case studies present analysis and design of such mechanisms in real systems. The mechanisms for providing QoS considering signaling and service data paths and their relationship at the DVB-H link layer are analyzed as the first case study. In particular the performance of different service data decoding mechanisms and optimal signaling transmission parameter selection are presented. The second case study investigates the design of signaling and service data paths for the more modern DVB-T2 physical layer. Furthermore, by comparing the performances of the signaling and service data paths by simulations, configuration guidelines for the DVB-T2 physical layer signaling are given. The presented guidelines can prove useful when configuring DVB-T2 transmission networks. Finally, recommendations for the design of data and signalling paths are given based on findings from the case studies. The requirements for the signaling design should be derived from the requirements for the main services. Generally, these requirements for signaling should be more demanding as the signaling is the enabler for service reception.

Choice of Business Process Modeling Methodology - Case Northern Dimension Research Centre (NORDI) in Lappeenranta University of Technology

The main outcome of the master thesis is innovative solution, which can support a choice of business process modeling methodology. Potential users of this tool are people with background in business process modeling and possibilities to collect required information about organization’s business processes. Master thesis states the importance of business process modeling in implementation of strategic goals of organization. It is made by revealing the place of the concept in Business Process Management (BPM) and its particular case Business Process Reengineering (BPR). In order to support the theoretical outcomes of the thesis a case study of Northern Dimension Research Centre (NORDI) in Lappeenranta University of Technology was conducted. On its example several solutions are shown: how to apply business process modeling methodologies in practice; in which way business process models can be useful for BPM and BPR initiatives; how to apply proposed innovative solution for a choice of business process modeling methodology.

A Development and Application of a Three-Dimensional Model for a CFB Gasifier

The developing energy markets and rising energy system costs have sparked the need to find new forms of energy production and increase the self-sufficiency of energy production. One alternative is gasification, whose principles have been known for decades, but it is only recently when the technology has become a true alternative. However, in order to meet the requirements of modern energy production methods, it is necessary to study the phenomenon thoroughly. In order to understand the gasification process better and optimize it from the viewpoint of ecology and energy efficiency, it is necessary to develop effective and reliable modeling tools for gasifiers. The main aims of this work have been to understand gasification as a process and furthermore to develop an existing three-dimensional circulating fluidized bed modeling tool for modeling of gasification. The model is applied to two gasification processes of 12 and 50 MWth. The results of modeling and measurements have been compared and subsequently reviewed. The work was done in co-operation with Lappeenranta University of Technology and Foster Wheeler Energia Oy.

Motivational Influences on Transfer: Dimensions and Boundary Conditions

The focus of this dissertation is the motivational influences on transfer in higher education and professional training contexts. To estimate these motivational influences, the dissertation includes seven individual studies that are structured in two parts. Part I, Dimensions, aims at identifying the dimensionality of motivation to transfer and its structural relations with training-related antecedents and outcomes. Part II, Boundary Conditions, aims at testing the predictive validity of motivation theories used in contemporary training research under different study conditions. Data in this dissertation was gathered from multi-item questionnaires, which were analyzed differently in Part I and Part II. Studies in Part I employed exploratory and confirmatory factor analysis, structural equation modeling, partial least squares (PLS) path modeling, and mediation analysis. Studies in Part II used artifact distribution meta-analysis, (nested) subgroup analysis, and weighted least squares (WLS) multiple regression. Results demonstrate that motivation to transfer can be conceptualized as a three-dimensional construct, including autonomous motivation to transfer, controlled motivation to transfer, and intention to transfer, given a theoretical framework informed by expectancy theory, self-determination theory, and the theory of planned behavior. Results also demonstrate that a range of boundary conditions moderates motivational influences on transfer. To test the predictive validity of expectancy theory, social cognitive theory, and the theory of goal orientations under different study settings, a total of 17 boundary conditions were meta-analyzed, including age; assessment criterion; assessment source; attendance policy; collaboration among trainees; computer support; instruction; instrument used to measure motivation; level of education; publication type; social training context; SS/SMC bias; study setting; survey modality; type of knowledge being trained; use of a control group; and work context. Together, the findings cumulated in this thesis support the basic premise that motivation is centrally important for transfer, but that motivational influences need to be understood from a more differentiated perspective than commonly found in the literature, in order to account for several dimensions and boundary conditions. The results of this dissertation across the seven individual studies are reflected in terms of their implications for theory development and their significance for training evaluation and the design of training environments. Limitations and directions to take in future research are discussed.

Software Development Process Modeling. Developers Perspective to Contemporary Modeling Techniques

Formal software development processes and well-defined development methodologies are nowadays seen as the definite way to produce high-quality software within time-limits and budgets. The variety of such high-level methodologies is huge ranging from rigorous process frameworks like CMMI and RUP to more lightweight agile methodologies. The need for managing this variety and the fact that practically every software development organization has its own unique set of development processes and methods have created a profession of software process engineers. Different kinds of informal and formal software process modeling languages are essential tools for process engineers. These are used to define processes in a way which allows easy management of processes, for example process dissemination, process tailoring and process enactment. The process modeling languages are usually used as a tool for process engineering where the main focus is on the processes themselves. This dissertation has a different emphasis. The dissertation analyses modern software development process modeling from the software developers’ point of view. The goal of the dissertation is to investigate whether the software process modeling and the software process models aid software developers in their day-to-day work and what are the main mechanisms for this. The focus of the work is on the Software Process Engineering Metamodel (SPEM) framework which is currently one of the most influential process modeling notations in software engineering. The research theme is elaborated through six scientific articles which represent the dissertation research done with process modeling during an approximately five year period. The research follows the classical engineering research discipline where the current situation is analyzed, a potentially better solution is developed and finally its implications are analyzed. The research applies a variety of different research techniques ranging from literature surveys to qualitative studies done amongst software practitioners. The key finding of the dissertation is that software process modeling notations and techniques are usually developed in process engineering terms. As a consequence the connection between the process models and actual development work is loose. In addition, the modeling standards like SPEM are partially incomplete when it comes to pragmatic process modeling needs, like light-weight modeling and combining pre-defined process components. This leads to a situation, where the full potential of process modeling techniques for aiding the daily development activities can not be achieved. Despite these difficulties the dissertation shows that it is possible to use modeling standards like SPEM to aid software developers in their work. The dissertation presents a light-weight modeling technique, which software development teams can use to quickly analyze their work practices in a more objective manner. The dissertation also shows how process modeling can be used to more easily compare different software development situations and to analyze their differences in a systematic way. Models also help to share this knowledge with others. A qualitative study done amongst Finnish software practitioners verifies the conclusions of other studies in the dissertation. Although processes and development methodologies are seen as an essential part of software development, the process modeling techniques are rarely used during the daily development work. However, the potential of these techniques intrigues the practitioners. As a conclusion the dissertation shows that process modeling techniques, most commonly used as tools for process engineers, can also be used as tools for organizing the daily software development work. This work presents theoretical solutions for bringing the process modeling closer to the ground-level software development activities. These theories are proven feasible by presenting several case studies where the modeling techniques are used e.g. to find differences in the work methods of the members of a software team and to share the process knowledge to a wider audience.

Towards sustainable Iron- and steelmaking with economic optimization

The iron and steelmaking industry is among the major contributors to the anthropogenic emissions of carbon dioxide in the world. The rising levels of CO2 in the atmosphere and the global concern about the greenhouse effect and climate change have brought about considerable investigations on how to reduce the energy intensity and CO2 emissions of this industrial sector. In this thesis the problem is tackled by mathematical modeling and optimization using three different approaches. The possibility to use biomass in the integrated steel plant, particularly as an auxiliary reductant in the blast furnace, is investigated. By pre-processing the biomass its heating value and carbon content can be increased at the same time as the oxygen content is decreased. As the compression strength of the preprocessed biomass is lower than that of coke, it is not suitable for replacing a major part of the coke in the blast furnace burden. Therefore the biomass is assumed to be injected at the tuyere level of the blast furnace. Carbon capture and storage is, nowadays, mostly associated with power plants but it can also be used to reduce the CO2 emissions of an integrated steel plant. In the case of a blast furnace, the effect of CCS can be further increased by recycling the carbon dioxide stripped top gas back into the process. However, this affects the economy of the integrated steel plant, as the amount of top gases available, e.g., for power and heat production is decreased. High quality raw materials are a prerequisite for smooth blast furnace operation. High quality coal is especially needed to produce coke with sufficient properties to ensure proper gas permeability and smooth burden descent. Lower quality coals as well as natural gas, which some countries have in great volumes, can be utilized with various direct and smelting reduction processes. The DRI produced with a direct reduction process can be utilized as a feed material for blast furnace, basic oxygen furnace or electric arc furnace. The liquid hot metal from a smelting reduction process can in turn be used in basic oxygen furnace or electric arc furnace. The unit sizes and investment costs of an alternative ironmaking process are also lower than those of a blast furnace. In this study, the economy of an integrated steel plant is investigated by simulation and optimization. The studied system consists of linearly described unit processes from coke plant to steel making units, with a more detailed thermodynamical model of the blast furnace. The results from the blast furnace operation with biomass injection revealed the importance of proper pre-processing of the raw biomass as the composition of the biomass as well as the heating value and the yield are all affected by the pyrolysis temperature. As for recycling of CO2 stripped blast furnace top gas, substantial reductions in the emission rates are achieved if the stripped CO2 can be stored. However, the optimal recycling degree together with other operation conditions is heavily dependent on the cost structure of CO2 emissions and stripping/storage. The economical feasibility related to the use of DRI in the blast furnace depends on the price ratio between the DRI pellets and the BF pellets. The high amount of energy needed in the rotary hearth furnace to reduce the iron ore leads to increased CO2 emissions.

Pienvesivoimalanmallinnus ja jakeluverkkovaikutusten tarkastelu

Tässä työssä simuloitiin Valkealassa sijaitsevaa Tirvan pienvesivoimalaitosta ja sen vaikutusta sähkönjakeluverkkoon. Pienvesivoimalaitos mallinnettiin PSCAD-ympäristöön verkko- ja voimalaitostietojen perusteella. Sähköverkko kuvattiin malliin koko 110 kV:n siirtävän verkon ja Tirvan pienjänniteverkon väliltä. Mallin avulla tehtiin sarja hajautettua sähköntuotantoa koskevia tarkasteluita. Tarkasteluissa huomattiin voimalaitoksen verkkoonliitynnän aiheuttavan standardien ylärajoilla olevan transienttisen muutoksen voimalaitoksen jännitteisiin. Työssä tehtiin yksityiskohtaisempi jännitehäviöiden mittaus voimalaitoksen pullonkaulana toimivalle pienitehoiselle jakelumuuntajalle. Tuotannon lisäämisen yhteydessä näkyvän yllättävän jännitteen laskun syyt paikannettiin muuntajalla tapahtuviin loistehon siirrosta johtuviin ylimääräisiin jännitehäviöihin. Voimalaitoksella ei ole merkittävää vaikutusta vikatilanteiden virtoihin.

Prosessimaisen toimintatavan soveltuvuus konepajan liiketoimintaprosessien johtamiseen

Kiristyvä kilpailu ja nopeat ympäristömuutokset aiheuttavat haasteita organisaatioiden johtamiseen. Yritykseltä edellytetään samaan aikaan reagointikykyä, joustavuutta, asiakasläheisyyttä sekä kustannustehokkuutta. Näihin haasteisiin voidaanvastata prosessimaisella toimintatavalla. Tämän työn tavoitteena on arvioida prosessimaisen toimintatavan soveltuvuutta konepajan toimintojenjohtamiseen ja arvioida millaisia hyötyjä prosessimaisella toimintatavalla voidaan saavuttaa. Työn teoriaosuudessa on perehdytty prosessiajattelun terminologiaan, prosessimaisen toiminnan kehittämiseen, avainprosessien tunnistamiseen ja prosessien kuvaamiseen sekä prosessien suorituskyvyn mittaamiseen. Työn käytännön osuudessa on perehdytty yrityksen toimintojen johtamiseen ja niissä ilmenneisiin ongelmiin, joihin prosessimaisella toiminnalla voitaisiin vaikuttaa. Lisäksi on huomioitu mitä ongelmia prosessimaisen toiminnan implementoinnissa saattaa esiintyä. Työssä on esitelty malli, jonka mukaisesti prosessimaista toimintaa voidaan yrityksessä kehittää. Työn tuloksena yrityksen avainprosessit on tunnistettu ja niistä on muodostettu prosessikartta sekä yrityksen tarjous- ja myyntiprosessi on kuvattu prosessinkuvausmenetelmällä.

Tietojohtaminen innovaatioyhteistyössä

Avoimen innovaation soveltaminen ja yhteistyö innovaatiotoiminnassa tarjoavat yrityksille mahdollisuuden tuoda markkinoille yhä kompleksisempia ja vaativampia tuotteita. Yhteistyön ongelmallisuus korostuu erilaisten käytäntöjen ja toteuttamistapojen yhteensovittamisessa. Tämän diplomityön tavoitteena oli luoda järjestelmällinen viitekehys monirajapintaisen innovaatioprosessin toteuttamiseen. Työssä sovellettiin keskeisiä teorioita niin tietojohtamisen, innovaatioprosessimallinnuksen kuin innovaatioyhteistyön saroilta. Empiirinen tutkimus toteutettiin asiantuntijahaastatteluiden avulla. Työ on osa TEKESin rahoittamaa tutkimusprojektia ”Liiketoimintakonseptien mallintaminen tuotteistettaessa ja kaupallistettaessa muovimekaniikkaosaamista”.

Mittausmenetelmien kehittaminen kuplakolonnille

Kuplakolonnireaktoreiden CFD-mallinnus on talla hetkella voimakkaasti kehittyva tutkimusalue. Kaksifaasivirtauksen luotettava simulointi ja mallintaminen on haastavaa kuplakolonnireaktorissa tapahtuvien ilmioiden monimutkaisuuden vuoksi. Reaktorin kayttaytymiseen vaikuttavat tekijat, kuten kolonnin hydrodynamiikka ja aineensiirto, tulee tuntea hyvin ennen mallien tekoa. Tassa tyossa on kokeellisesti tutkittu erilaisten mittausmenetelmien soveltuvuutta kuplakolonnin hydrodynamiikan tutkimiseen. Mittausmenetelmissa on keskitytty erityisesti CFD-mallien vaatimiin paikallisiin mittauksiin. Lisaksi tyossa on arvioitu mittausmenetelmien soveltuvuutta j a luotettavuutta CFD-mallien validointiin. Tyon kirjallisuusosassa on perehdytty kuplakolonnireaktorin hydrodynaamiseen kayttaytymiseen ja siihen vaikuttaviin tekijoihin. Naita ovat mm. reaktorityypit, kaasun dispergointi, virtaustyypit ja -alueet, kaasun tilavuusosuus, kaasukuplan koko ja kuplan nousunopeus. Mittauksia tehtiin kahdessa erikokoisessa kuplakolonnissa, joista pienemman halkaisija oli 0,078 m ja suuremman 0,182 m. Molempien kolonnien nestepinnan korkeus oli 4,62 m. Mittaukset tehtiin vesijohtovedella ja epaorgaanisella prosessiliuoksella. Hydrodynaamisista ominaisuuksista mitattiin kaasun tilavuusosuus, kaasukuplan koko seka kaasukuplan nousunopeus. Kaasun tilavuusosuusmittaukset tehtiin paaasiassa paine-eromittauksella ja joissakin tapauksissa pinnanmittausmenetelmalla. Kuplakoko- ja kuplan nousunopeusmittaukset tehtiin suumopeusvideokameralla ja laser Doppler-anemometrilla. Mittauksissa kaytettiin kahdeksaa erilaista kaasunjakolaitetta, joilla selvitettiin kaasunjakolaitteen ominaisuuksien vaikutusta kolonnin hydrodynamiikkaan. Tuloksista havaittiin, etta nestefaasin ominaisuuksilla oli suuri vaikutus kolonnin hydrodynaamiseen kayttaytymiseen. En kaasunjakolaitteilla vesijohtovedella mitatut hydrodynaamiset ominaisuudet eivat poikenneet paljoa toisistaan, kun taas prosessiliuoksella kaasunjakolaitteiden valille saatiin huomattavat erot. Mittausmenetelmista laser Doppler-anemometri ei kaytettavissa olleella optiikalla soveltunut kaasukuplien mittaamiseen. Kuplat olivat menetelmalle liian suuria. Suumopeusvideokamerallaja paine-eromittauksella paastiin hyviin tuloksiin.

Haulikkoratamelun minimoinnin suunnittelu

Työn tavoitteena oli tutkia kilpa- ja harjoitusammuntaan käytettävällä haulikkoradalla käytettäväksi soveltuvia passiivisia meluntorjuntamenetelmiä ja suunnitella niistä toimiva kokonaisuus kohderadoille siten, että rata-alueen läheisillä asuinalueilla alitetaan 50 dB LAIMax-taso sekä muilla alueilla ampumaratamelun ohjearvot. Aluksi tarkasteltiin kohderatojen vanhoja menetelmiä ja radan meluntorjunnan kannalta olennaiset suunnat selvitettiin mittauksilla. Myös laukausmelun spektriä tutkittiin mittauksilla. Olemassa oleville menetelmille etsittiin korvaavia ja täydentäviä menetelmiä. Radan sijoittaminen maastoon on tärkeä osa meluntorjuntaa uutta rataa suunniteltaessa, mutta kohteena olleiden ratojen sijoittamista ei voitu enää muuttaa. Koska haulikkoammunnan säännöt eivät mahdollista aliääniammusten tai äänenvaimentimien käyttöä, ei varsinaista melupäästöä pystytä pienentämään. Melulle altistuvan kohteen sisätilojen suojaaminenkin on käytännössä hyödytöntä, koska ampumamelun ohjearvot ovat ulkoalueille. Ainoastaan melun absorptio, etenemisen estäminen ja ohjaaminen ovat kelvollisia menetelmiä kohderadoilla. Rata-alueelle suunniteltiin uudet ratojen väliset meluseinät, joiden ääneneristävyys ja -absorptio on vanhoja seiniä parempi. Taustavallille suunniteltiin jatkamista maavallina ja korottamista meluaitana, joka toimii myös haulienkierrätysjärjestelmän runkona. Alueen maaperä suunniteltiin muutettavaksi akustisesti pehmeämmäksi. Käytettävien menetelmien suunnittelussa tehtiin eri vaihtoehdoille laskennallisia arvioita, tietokonemallinnuksia ja laboratoriokokeita. Myös uusia menetelmiä haulikkoradan meluntorjunnassa tutkittiin. Tutkimusten perusteella näitä menetelmiä tutkitaan jatkossa käytännössä.

Paperikoneen viira- ja puristinosan mitoituslaskennan ohjeistaminen

Työssä laadittiin viira- ja puristinosan rungoston mitoituslaskentaa varten ohjeet FE-analysointiin. Työ suoritettiin keräämällä aluksi eri yksiköissä Valmetilla käytössä olevat mitoituslaskentaohjeet, aihetta käsittelevät muistiot ja diplomityöt sekä sekä keskustelemalla muiden viira- ja puristinosastolla laskentaa suorittavien suunnittelijoiden kanssa. Tämän jälkeen ohjeista koottiin ja täydennettiin yksi yhteinen ohjeisto, joka on jatkossa kaikkien laskijoiden käytössä. Valmiit ohjeet koottiin Valmetin Rautpohjan osastoiden yhteiseen Notes- järjestelmään. Ohjekannasta tehtiin sellainen, että siihen on helppo myöhemmin lisätä muiden rakenneryhmien ohjeita. Ohjeet jaettiin viiteen ryhmään ohjeiden lukemisen ja päivityksen helpottamiseksi. Mitoituslaskentaohjeiden käyttöä testattiin laskemalla yhden todellisen projektin puristinosan runkolaskelmat ohjeiden avulla. Yhteisen ohjeistuksen avulla yhtenäistettiin mallinnus- ja laskentatapoja niin Valmetin sisällä kuin mitoituslaskentaa tekevien alihankkijoiden keskuudessa.

A System-Level Simulation Model for a Protocol Processor

As the development of integrated circuit technology continues to follow Moore’s law the complexity of circuits increases exponentially. Traditional hardware description languages such as VHDL and Verilog are no longer powerful enough to cope with this level of complexity and do not provide facilities for hardware/software codesign. Languages such as SystemC are intended to solve these problems by combining the powerful expression of high level programming languages and hardware oriented facilities of hardware description languages. To fully replace older languages in the desing flow of digital systems SystemC should also be synthesizable. The devices required by modern high speed networks often share the same tight constraints for e.g. size, power consumption and price with embedded systems but have also very demanding real time and quality of service requirements that are difficult to satisfy with general purpose processors. Dedicated hardware blocks of an application specific instruction set processor are one way to combine fast processing speed, energy efficiency, flexibility and relatively low time-to-market. Common features can be identified in the network processing domain making it possible to develop specialized but configurable processor architectures. One such architecture is the TACO which is based on transport triggered architecture. The architecture offers a high degree of parallelism and modularity and greatly simplified instruction decoding. For this M.Sc.(Tech) thesis, a simulation environment for the TACO architecture was developed with SystemC 2.2 using an old version written with SystemC 1.0 as a starting point. The environment enables rapid design space exploration by providing facilities for hw/sw codesign and simulation and an extendable library of automatically configured reusable hardware blocks. Other topics that are covered are the differences between SystemC 1.0 and 2.2 from the viewpoint of hardware modeling, and compilation of a SystemC model into synthesizable VHDL with Celoxica Agility SystemC Compiler. A simulation model for a processor for TCP/IP packet validation was designed and tested as a test case for the environment.