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.

The Sottunga-Jurmo shear zone : structure and deformation history of a crustal-scale ductile shear zone in SW Finland

The aim of this study is to gain a better understanding of the structure and the deformation history of a NW-SE trending regional, crustal-scale shear structure in the Åland archipelago, SW Finland, called the Sottunga-Jurmo shear zone (SJSZ). Approaches involving e.g. structural geology, geochronology, geochemistry and metamorphic petrology were utilised in order to reconstruct the overall deformation history of the study area. The study therefore describes several features of the shear zone including structures, kinematics and lithologies within the study area, the ages of the different deformation phases (ductile to brittle) within the shear zone, as well as some geothermobarometric results. The results indicate that the SJSZ outlines a major crustal discontinuity between the extensively migmatized rocks NE of the shear zone and the unmigmatised, amphibolite facies rocks SW of the zone. The main SJSZ shows overall dextral lateral kinematics with a SW-side up vertical component and deformation partitioning into pure shear and simple shear dominated deformation styles that was intensified toward later stages of the deformation history. The deformation partitioning resulted in complex folding and refolding against the SW margin of the SJSZ, including conical and sheath folds, and in a formation of several minor strike-slip shear zones both parallel and conjugate to the main SJSZ in order to accommodate the regional transpressive stresses. Different deformation phases within the study area were dated by SIMS (zircon U-Pb), ID-TIMS (titanite U-Pb) and 40Ar/39Ar (pseudotachylyte wholerock) methods. The first deformation phase within the ca. 1.88 Ga rocks of the study area is dated at ca. 1.85 Ga, and the shear zone was reactivated twice within the ductile regime (at ca. 1.83 Ga and 1.79 Ga), during which the strain was successively increasingly partitioned into the main SJSZ and the minor shear zones. The age determinations suggest that the orogenic processes within the study area did not occur in a temporal continuum; instead, the metamorphic zircon rims and titanites show distinct, 10-20 Ma long breaks in deformation between phases of active deformation. The results of this study further imply slow cooling of the rocks through 600-700ºC so that at 1.79 Ga, 2 the temperature was still at least 600ºC. The highest recorded metamorphic pressures are 6.4-7.1 kbar. At the late stages or soon after the last ductile phase (ca. 1.79 Ga), relatively high-T mylonites and ultramylonites were formed, witnessing extreme deformation partitioning and high strain rates. After the rocks reached lower amphibolite facies to amphibolite-greenschist facies transitional conditions (ca. 500-550ºC), they cooled rapidly, probably due to crustal uplift and exhumation. The shear zone was reactivated at least once within the semi-brittle to brittle regime between ca. 1.79 Ga and 1.58 Ga, as evidenced by cataclasites and pseudotachylytes. In summary, the results of this study suggest that the Sottunga-Jurmo shear zone (and the South Finland shear zone) defines a major crustal discontinuity, and played a central role in accommodating the regional stresses during and after the Svecofennian orogeny.

The Sottunga-Jurmo shear zone : structure and deformation history of a crustal-scale ductile shear zone in SW Finland

The aim of this study is to gain a better understanding of the structure and the deformation history of a NW-SE trending regional, crustal-scale shear structure in the Åland archipelago, SW Finland, called the Sottunga-Jurmo shear zone (SJSZ). Approaches involving e.g. structural geology, geochronology, geochemistry and metamorphic petrology were utilised in order to reconstruct the overall deformation history of the study area. The study therefore describes several features of the shear zone including structures, kinematics and lithologies within the study area, the ages of the different deformation phases (ductile to brittle) within the shear zone, as well as some geothermobarometric results. The results indicate that the SJSZ outlines a major crustal discontinuity between the extensively migmatized rocks NE of the shear zone and the unmigmatised, amphibolite facies rocks SW of the zone. The main SJSZ shows overall dextral lateral kinematics with a SW-side up vertical component and deformation partitioning into pure shear and simple shear dominated deformation styles that was intensified toward later stages of the deformation history. The deformation partitioning resulted in complex folding and refolding against the SW margin of the SJSZ, including conical and sheath folds, and in a formation of several minor strike-slip shear zones both parallel and conjugate to the main SJSZ in order to accommodate the regional transpressive stresses. Different deformation phases within the study area were dated by SIMS (zircon U-Pb), ID-TIMS (titanite U-Pb) and 40Ar/39Ar (pseudotachylyte wholerock) methods. The first deformation phase within the ca. 1.88 Ga rocks of the study area is dated at ca. 1.85 Ga, and the shear zone was reactivated twice within the ductile regime (at ca. 1.83 Ga and 1.79 Ga), during which the strain was successively increasingly partitioned into the main SJSZ and the minor shear zones. The age determinations suggest that the orogenic processes within the study area did not occur in a temporal continuum; instead, the metamorphic zircon rims and titanites show distinct, 10-20 Ma long breaks in deformation between phases of active deformation. The results of this study further imply slow cooling of the rocks through 600-700ºC so that at 1.79 Ga, 2 the temperature was still at least 600ºC. The highest recorded metamorphic pressures are 6.4-7.1 kbar. At the late stages or soon after the last ductile phase (ca. 1.79 Ga), relatively high-T mylonites and ultramylonites were formed, witnessing extreme deformation partitioning and high strain rates. After the rocks reached lower amphibolite facies to amphibolite-greenschist facies transitional conditions (ca. 500-550ºC), they cooled rapidly, probably due to crustal uplift and exhumation. The shear zone was reactivated at least once within the semi-brittle to brittle regime between ca. 1.79 Ga and 1.58 Ga, as evidenced by cataclasites and pseudotachylytes. In summary, the results of this study suggest that the Sottunga-Jurmo shear zone (and the South Finland shear zone) defines a major crustal discontinuity, and played a central role in accommodating the regional stresses during and after the Svecofennian orogeny.

Resa i röstens landskap : en narrativ studie av hur lärare blir professionella röstanvändare

The theme of this thesis is the learning process that occurs when teachers become professional voice users. The aim is to explore what it (really) means to become a professional voice user in a teaching profession; thereby developing an understanding of how future education in this field can be arranged so as to both effectively prevent vocal problems and to develop oral didactical competence among teachers. The ambition is to describe, interpret, and understand the learning process through a combination of emic and ethic research perspectives. The theoretical frame of reference reflects the cross disciplinary character of the thesis. Voice problems are common among both student teachers and inservice teachers and adversely affect professional competence, identity and quality of life. Additionally, vocal problems are proven to have a negative impact on pupils´ learning. The individual elements of learning are explored in the light of experiential learning theory and transformative learning theory. The social elements of learning are explored in relation to the theory of situated learning. In addition, theories of teacher professionalisation in terms of competence and identity are outlined. The empirical study has a longitudinal and multi method character. It is anchored in a phenomenological hermeneutical tradition, more specifically in narrative inquiry. The point of departure is the learning experiences of ten student teachers, who attended a ten week long course on voice production as part of their teacher training at Åbo Akademi University, in the autumn of 2002 and the spring of 2003. Four interviews in the form of conversations were conducted with each participant. These were crystallised with a process diary, a Swedish Voice Handicap Index, a voice observation, and a video observation. A fifth interview was conducted with each participant five years post teacher training, in the spring of 2008. Participant observation was also conducted throughout the course. The research materials have been analysed and interpreted narratively using a phenomenological hermeneutical method. The results are presented descriptively as individual narratives, which are reflected in logopedic research materials. Learning is here understood as emergent awareness. This is followed by a meta narrative concerning learning as experiences in the four dimensions body, thought, feeling, and relation. Finally, interpretation is expressed with respect to the theory of relational education. Learning is here understood as a movement in the field between the actual and the possible voice. It is also viewed as fundamentally rooted in inter-human relationships, in moments of presence and coexistence. As a tentative answer to the call for an existential space for learning in order to be a professional voice user, I suggest the concept of a learning refuge as a locus for a learning process built on trust, mutuality and openness.

Musikalisk lärandemiljö : planerade musikaktiviteter med småbarn i daghem

A musically stimulating nvironment is of great significance when considering the opportunities for development and learning that are offered to children in day nurseries. Moreover, the quality of musical activities also has great significance for the musical development of growing children. Young children are always striving to create meaning and understanding; they influence and are influenced by the context in which they are situated. The purpose of this study is to investigate the planned music activities in the musical learning environment of seven toddler’s groups in day nurseries, based on four different aspects: the texts of children’s songs, the melodies of children’s songs, the basic elements of music and the use of instrumentation. The data has been gathered by video observation of the planned music activities. The age of the children studied ranged from 11 months to 3 years and 11 months, and on average there were 13 children in each group. The study involved a total of just over 90 children and nine educators. The methodological approaches are hermeneutic as well as videographic, and they are applied to the analysis as required. The approaches are well suited to an understanding of the planned music activities where the individual’s communications and actions are studied. The results of the study show that educators impart a cultural heritage to the children in the form of old traditional songs, but they also act as intermediaries for newer children's songs. They focus on actively on the text content of the children’s songs in their interaction with the children, but do not address the meaning of the text. Furthermore, while the educators use music sessions for the children to develop, among other things, an understanding of language and social skills, they do not use the sessions to develop the children’s musical skills. The educators could, to a much greater extent than they now do, direct the children's attention to the basic elements of music, and conduct meta-cognitive dialogues with the children. They use a large repertoire of children's songs, which are, however, often too demanding for the children’s voices to cope with. In addition, the educators do not plan, in any significant way, activities for the toddlers in order to help them develop the accuracy of their vocal tones. With regard to the use of instruments, the educators focus, in their interaction with the children, is placed on both the usage of the instruments and knowledge about the instruments. Regarding the use of instruments the study shows that the children’s musical expression takes place in an environment that includes both melody and rhythm instruments. It is clear that children are actively interested in the constructed instrument environment, because for long periods of time they independently play and experiment with instruments.

Yliopiston yrittäjämäisyyden sosiaalinen rakentuminen: case Aalto-yliopisto

Keskustelu yrittäjyyden sijoittumisesta yliopistojen tehtäväkenttään on muodostunut 2000-luvun aikana osaksi yhteiskunnallista ja maailmanlaajuista korkeakoulutuksen muutosta. Tämän tutkimuksen tarkoituksena on lisätä ymmärrystä yliopiston yrittäjämäisyyden sosiaalisesta rakentumisesta. Lähestyn yliopiston sisällä tuotettua moniäänistä yrittäjyyspuhetta yliopiston yrittäjämäisyyden todellisuuden representaationa, ja pyrin tekemään siitä selkoa kommunikaatioon kohdistuvan analyysin avulla. Ilmiön empiirinen tarkastelu pohjautuu Aalto-yliopistossa ja sitä edeltäneessä Teknillisessä korkeakoulussa vuosina 2006–2013 kerättyihin tekstiaineistoihin. Aineistojen tulkinta tuottaa monikerroksellista tietoa ilmiöstä niin yksilö- kuin organisaatiotasolla. Tarkastelen tutkimuksessani millaisia merkityksenantoja yrittäjyydelle ja yrittäjämäisyydelle annetaan yliopiston sisällä eri näkökulmista katsottuna, kun yliopisto käy läpi merkittävää organisaatiorakenteellista ja institutionaalista muutosta. Tutkimusasetelman neljä näkökulmaa perustuvat tekniikan alan jatko-opiskelijoiden puheeseen, TKK:n opetussuunnitelmatekstiin, Aalto-yliopiston opettajien puheeseen ja johdon tuottamaan strategiatekstiaineistoon. Tutkimuksen tulosten mukaan käynnissä on ollut akateemisten arvojen ja arvojärjestelmien laajentumisen aika ja tila, jossa yrittäjämäisyys astuu areenalle, mutta sen suppeat tulkinnat eivät tarjoa mahdollisuuksia ruohonjuuritason kiinnittymiseen akateemisesta kulttuurista käsin. Yrittäjyyden ja yrittäjämäisyyden saamat taloudelliskaupalliset merkitykset koetaan uhkaksi, eikä tilannetta helpota yleisesti uuvuttavaksi koettu rakenteellinen ja yhteiskunnallinen yliopiston muutosvaihe. Hallitsevat tarinalinjat kuten puhe kilpailukyvystä ja kilpailutilanteen kovenemisesta tuottavat odotusten viitekehyksen, joilla yliopiston toimintaa raamitetaan ulkoapäin. Yrittäjyyteen laajassa merkityksessä sisältyvät mahdollisuudet jäävät niin ikään hyödyntämättä, ja lukuisat edistämistoiminnot kilpistyvät sosiaalisesti rakentuviin esteisiin. Tässä tutkimuksessa rakentuva laajennettu yliopiston yrittäjämäisyyden viitekehys pyrkii palvelemaan moniäänistymisen tarkoitusta käsitteellisellä tasolla ja avaamaan uusia mahdollisuuksia yliopiston yrittäjämäisyyden edistämiselle.

Computational models for and from biology : simple gene assembly and reaction systems

The advancement of science and technology makes it clear that no single perspective is any longer sufficient to describe the true nature of any phenomenon. That is why the interdisciplinary research is gaining more attention overtime. An excellent example of this type of research is natural computing which stands on the borderline between biology and computer science. The contribution of research done in natural computing is twofold: on one hand, it sheds light into how nature works and how it processes information and, on the other hand, it provides some guidelines on how to design bio-inspired technologies. The first direction in this thesis focuses on a nature-inspired process called gene assembly in ciliates. The second one studies reaction systems, as a modeling framework with its rationale built upon the biochemical interactions happening within a cell. The process of gene assembly in ciliates has attracted a lot of attention as a research topic in the past 15 years. Two main modelling frameworks have been initially proposed in the end of 1990s to capture ciliates’ gene assembly process, namely the intermolecular model and the intramolecular model. They were followed by other model proposals such as templatebased assembly and DNA rearrangement pathways recombination models. In this thesis we are interested in a variation of the intramolecular model called simple gene assembly model, which focuses on the simplest possible folds in the assembly process. We propose a new framework called directed overlap-inclusion (DOI) graphs to overcome the limitations that previously introduced models faced in capturing all the combinatorial details of the simple gene assembly process. We investigate a number of combinatorial properties of these graphs, including a necessary property in terms of forbidden induced subgraphs. We also introduce DOI graph-based rewriting rules that capture all the operations of the simple gene assembly model and prove that they are equivalent to the string-based formalization of the model. Reaction systems (RS) is another nature-inspired modeling framework that is studied in this thesis. Reaction systems’ rationale is based upon two main regulation mechanisms, facilitation and inhibition, which control the interactions between biochemical reactions. Reaction systems is a complementary modeling framework to traditional quantitative frameworks, focusing on explicit cause-effect relationships between reactions. The explicit formulation of facilitation and inhibition mechanisms behind reactions, as well as the focus on interactions between reactions (rather than dynamics of concentrations) makes their applicability potentially wide and useful beyond biological case studies. In this thesis, we construct a reaction system model corresponding to the heat shock response mechanism based on a novel concept of dominance graph that captures the competition on resources in the ODE model. We also introduce for RS various concepts inspired by biology, e.g., mass conservation, steady state, periodicity, etc., to do model checking of the reaction systems based models. We prove that the complexity of the decision problems related to these properties varies from P to NP- and coNP-complete to PSPACE-complete. We further focus on the mass conservation relation in an RS and introduce the conservation dependency graph to capture the relation between the species and also propose an algorithm to list the conserved sets of a given reaction system.

Remembering the War and Aggression: A Discourse Analysis of Japan’s State Apologies and Commemoration Speeches on August 15th 1995-2015

Memories of historical injustices affect contemporary politics from local to global level. In East Asia, questions of commemoration and historical responsibility have turned into international and domestic controversies. The main focus has been and still is in apologies conducted by Japanese prime ministers in regards to the war, aggression and colonialism during the era of Imperial Japan. Although it is granted that state apologies are not a crucial part of reconciliation, they can be analysed as a linked but separate process within the context of memory and international relations. The purpose of this study is to examine the discourses of history in Japanese prime ministers’ commemoration speeches on Memorial Ceremony for the War Dead from 1995 to 2015 in order to analyse how the Japanese government is reflecting on its past. In particular, attention is paid on what is being commemorated and how, whether it is the war and its victims or Japan’s post-war era of peace. As an apology is a reciprocal activity, responses from Japan’s most vocal former victims, South Korea and China, were also examined. Discourse analysis was used to identify and examine the different representations of the past. In addition, the apology statements of Japanese prime ministers were analysed in the Many to Many apology framework developed by Tavuchis (1991). Primary material consisted of 21 prime ministers’ speeches from the annual Memorial Ceremony for the War Dead on August 15th and from three apology statements made in 1995, 2005 and 2015. Further international context was primarily collected from newspaper articles of The New York Times and The Times throughout the examined period. It can be concluded from the findings that in the official Japanese remembrance of the past war from 1985’s annexation of Taiwan to the atomic bombings in 1945, both discourses that reinforce apology and remorse over Japan’s past aggressions and discourses that consciously avoid doing so are used. The commemoration speeches and apology statements consistently assert that Japan has acknowledged its past and expresses regret over the acts of aggression. At the same time, the speeches and statements strengthen the narrative that Japan was a victim of circumstances as well as turn the focus on post-war peace-making or on Japan’s own victimhood.