<p>The use of supplementary cementitious materials (SCM) decreases the environmental impact of the cement industry. SCMs are commercial by-products that possess pozzolanic properties. Recycled glass powder, classified as a SCM, when added as a cement replacement reacts with the available lime in the cement to form calcium silicate hydrate (C-S-H) products. In contrast with other SCMs, glass is siliceous and thus the reaction can also cause alkali silica reaction (ASR) which causes expansion and cracking. This study was completed in order to characterize the chemical reactions and their rate using a simplified system that mimics glass particles in hardened cement paste.</p> <p>Silica powder was added to solutions containing calcium hydroxide and/or sodium hydroxide. The rate of dissolution of the silica was monitored as well as the composition of the reaction products. Dissolution rates of silica with varying concentrations of silica, calcium hydroxide and sodium hydroxide, were fitted to the Hixson-Crowell cubic root law. The precipitate composition of the reaction product was represented by means of triaxial plots. It was found that silicate ions enter the solutions containing sodium hydroxide and containing both sodium hydroxide and calcium hydroxide. The rate is proportional to the quantity of sodium ions in the solution and to the pH. Also, higher concentrations of silica generally cause higher dissolution rates. The solutions with a pH of 13.48 and with lower silica concentrations created reaction products that were similar to C-S-H while the solutions with higher pH levels formed ASR after thirty days. The C-S-H prevented further dissolution of the silica. The formation of the ASR reaction products did not prevent further dissolution of the silica and they continued to dissolve until most of the silica had entered the solution.</p> / Master of Applied Science (MASc)

Managed aquifer recharge (MAR) is the purposeful recharge of an aquifer for later recovery or environmental benefits and represents a valuable method for sustainable water resources management. Models can be helpful tools for the assessment of MAR systems. This review encompasses a survey and an analysis of case studies which apply flow and transport models to evaluate MAR. The observed modeling objectives include the planning or optimization of MAR schemes as well as the identification and quantification of geochemical processes during injection, storage and recovery. The water recovery efficiency and the impact of the injected water on the ambient groundwater are further objectives investigated in the reviewed studies. These objectives are mainly solved by using groundwater flow models. Unsaturated flow models, solute transport models, reactive geochemical models as well as water balance models are also frequently applied and often coupled. As each planning step to setup a new MAR facility requires cost and time investment, modeling is used to minimize hazard risks and assess possible constraints of the system such as low recovery efficiency, clogging and geochemical processes.

In der vorliegenden Dissertation sollten die hydrogeochemischen Prozesse herausgearbeitet werden, die für die Wasserqualitätsänderung während eines ASR Experiments in Bolivar, Südaustralien und während der Versickerung in einem künstlichen Grundwasseranreicherungsbecken in Berlin von Bedeutung waren. Reaktive Stofftransportmodellierung des ASR Experiments in Bolivar, Südaustralien zeigte, dass die hydrochemischen Veränderungen in der direkten Umgebung des Injektionsbrunnens während der Speicherphase nur durch rapide Änderungen der Sauerstoff- und Nitrat reduzierenden Bakterienmasse erklärt werden können. Die hydrochemischen Veränderungen in größerer Distanz zum Injektionsbrunnen wurden überwiegend durch Ionenaustauschprozesse und Kalzitlösung verursacht. Geochemische und hydraulische Messungen unter einem Sickerbecken in Berlin zeigten, dass die beobachteten geochemischen Änderungen im Sickerwasser mit den periodisch auftretenden wassergesättigten/wasserungesättigen Bedingungen unter dem Becken einhergehen. Während der ungesättigten Periode wird Luft unter das Becken gezogen und führt zur plötzlichen Reoxidierung von bereits in der gesättigten Periode gebildeten Eisensulfiden und zur beschleunigten Mineralisation von sedimentärem organischem Kohlenstoff. Reaktive Stofftransportmodellierung auf größerer Skale zeigte, dass allein die saisonalen Temperaturunterschiede im Infiltrationswasser für die beobachtete zeitliche und räumliche Dynamik der Redoxzonen im weiteren Abstrom des Sickerbeckens verantwortlich sind. Das Abbauverhalten der Arzneimittelsubstanz Phenazon hängt ausschließlich von der Verfügbarkeit von gelöstem Sauerstoff und damit indirekt von der Wassertemperatur im Aquifer ab. In der vorliegenden Arbeit wird deutlich, dass ein adäquates Verständnis der wasserqualitätsändernden Prozesse in künstlichen Anreicherungsystemen nur dann erreicht werden kann wenn Strömung, Transport und reaktive Prozesse, im Feld als auch in der Modellierung, simultan betrachtet werden. / In this thesis, three major studies were carried out in order to understand the key factors controlling the water quality changes that occurred during a reclaimed water Aquifer Storage and Recovery (ASR) experiment at Bolivar, South Australia and during ponded infiltration in Berlin, Germany. Multi-component reactive transport modelling of the ASR experiment suggested that during the storage phase, dynamic changes in bacterial mass have a significant influence on the local geochemistry in the vicinity of the injection well. Water quality changes further away from the injection well were mainly driven by ion exchange and calcite dissolution. Geochemical and hydraulic measurements below an artificial recharge pond in Berlin, Germany, showed that the observed dynamic changes of the hydrochemistry within the seepage water are strongly linked to the periodic saturated/unsaturated hydraulic conditions below the pond. During unsaturated conditions, atmospheric oxygen penetrates from the pond margins to the centre below the pond, leading to (i) a sudden re-oxidation of sulphide minerals that have formed previously during saturated conditions and (ii) an enhanced mineralisation of sedimentary particulate organic carbon. Reactive transport modelling showed that at larger scale, seasonal temperature changes of the infiltration water are the key control for the observed temporal and spatial redox dynamics further downstream the recharge pond. Moreover, the degradation behaviour of the pharmaceutically residue phenazone solely depends on the availability of dissolved oxygen, and thus indirectly on the water temperature within the aquifer. Overall this thesis shows that a sound understanding and analysis of the key processes affecting the water quality changes during artificial recharge of groundwater could only be achieved when flow, transport and reactive processes are considered simultaneously, both in the field and during modelling.

La technologie de l’électrolyse de la vapeur d’eau à haute température (EVHT) est unesolution alternative à la production d’hydrogène. Le principe est inversé à celui d’une pile àcombustible de type SOFC : on utilise la vapeur d’eau et de l’électricité afin de produire del’hydrogène. Une difficulté technique majeure repose sur la mise au point d’interconnecteursfonctionnant efficacement sur le long terme. Sur le plan électrique, l’interconnecteur doitprésenter une valeur de résistance de contact aux électrodes la plus faible possible, car elleaffecte directement le rendement de conversion électrochimique (eau en hydrogène) et peutpénaliser le procédé. Il ne doit donc pas présenter une cinétique d’oxydation élevée ni formerdes oxydes isolants électriquement. Sur le plan chimique, l’interconnecteur doit être résistantà l’oxydation sous atmosphère riche en oxygène côté anode et riche en vapeur d’eau côtécathode. De plus, le problème de la volatilisation des oxydes de chrome, qui peuvent diffuseret empoisonner les électrodes, déterminant ainsi une réduction de l’activité électrochimique etdes performances du « stack » sur des longues durées de fonctionnement, doit être réduit. Latempérature de fonctionnement comprise entre 700 et 900°C permet l’utilisationd’interconnecteurs métalliques, qui présentent l’avantage d’une mise en oeuvre plus facile etd’un coût plus faible par rapport aux interconnecteurs céramiques.Dans cette étude, deux matériaux ont été testés en tant qu’interconnecteurs pour lessystèmes EVHT : un acier ferritique chromino-formeur K41X et un alliage Fe-Ni-Co necontenant pas de chrome. Le comportement envers la corrosion à haute température et laconductivité électrique des deux alliages ont été évalués à 800°C sous un mélange 95%O2-5%H2O, pour le côté anodique, et 10%H2-90%H2O, pour le côté cathodique. Pour l’alliageK41X, l’effet de l’état initial de la surface des échantillons sur la nature des oxydes formés àhaute température sous mélange H2-H2O a été pris en compte, à travers une comparaison desalliages bruts de laminage avec des surfaces polies miroir. L’effet d’une pré-oxydation decourte durée à 800°C sur le comportement à haute température de l’alliage K41X brut deréception sous atmosphère H2-H2O a également été évalué. Mais, le travail le plus original decette étude a consisté à effectuer des essais de marquage à l’or et des marquages isotopiquessous mélange H216O-H218O, H2-D2O et D2-H2O. Ces tests ont permis d’étudier lesmécanismes responsables de la croissance de la couche de corrosion de l’alliage K41X brut deréception et poli miroir à 800°C sous atmosphère H2-H2O et d’évaluer le rôle de la vapeurd’eau et de l’hydrogène dans le mécanisme d’oxydation / The high temperature water vapour electrolysis offers a promising method for highlyefficient hydrogen production. It works as an inverse solid oxide fuel cell, using water vapourand electricity in order to produce hydrogen. A major technical difficulty related to hightemperature water vapour electrolysis (HTVE) is the development of interconnects workingefficiently on a long period. From the electrical point of view, the interconnect must have alow contact resistance with the electrodes. Indeed, it directly affects the electrochemicalconversion efficiency (water into hydrogen) and it can penalize the process. The interconnectmust present a slow oxidation kinetics and form as less as possible electrical insulatingoxides. From the chemical point of view, the interconnect has to be resistant against oxidationin an oxygen rich atmosphere (anode side) and water vapour rich atmosphere (cathode side).Moreover, the problem of the volatility of chromium oxide species, which might migrate andpoison the electrodes, leading to a decrease in their electrochemical activity and degradationof stack performance, over long-term operation, needs to be reduced. The operatingtemperature between 700°C and 900°C allows the use of metallic interconnects, which havehigher electrical and thermal conductivities, easier shaping and lower cost, with respect to theceramic materials.In this study, two materials were tested as interconnects for the HTVE systems: a ferriticchromia-forming alloy, the K41X, and a Fe-Ni-Co alloy, which does not contain chromium.High temperature corrosion behaviour and electrical conductivity were tested in both anode(95%O2-5%H2O) and cathode (10%H2-90%H2O) atmospheres at 800°C. Moreover, for theK41X alloy, the effect of the initial surface state of the samples on the chemical nature of theoxides formed at 800°C in H2-H2O atmosphere was evaluated, by comparing as received andmirror polished surfaces. The effect of a short-term air preoxidation at 800°C on the hightemperature behaviour of the K41X as received sample in H2-H2O atmosphere was tested.The most original part of this study consisted in the investigation of the oxidation mechanismsof both as received and mirror polished K41X samples at 800°C in H2-H2O atmosphere bymeans of marking experiments using Au and isotopes (H216O-H218O mixture). Moreover,marking tests using H2-D2O and D2-H2O were carried out, in order to further investigate therole of hydrogen and water vapour in the oxidation mechanism

Managed aquifer recharge (MAR) is the purposeful recharge of an aquifer for later recovery or environmental benefits and represents a valuable method for sustainable water resources management. Models can be helpful tools for the assessment of MAR systems. This review encompasses a survey and an analysis of case studies which apply flow and transport models to evaluate MAR. The observed modeling objectives include the planning or optimization of MAR schemes as well as the identification and quantification of geochemical processes during injection, storage and recovery. The water recovery efficiency and the impact of the injected water on the ambient groundwater are further objectives investigated in the reviewed studies. These objectives are mainly solved by using groundwater flow models. Unsaturated flow models, solute transport models, reactive geochemical models as well as water balance models are also frequently applied and often coupled. As each planning step to setup a new MAR facility requires cost and time investment, modeling is used to minimize hazard risks and assess possible constraints of the system such as low recovery efficiency, clogging and geochemical processes.

Tal till text för relevant metadatataggning av ljudarkiv hos Sveriges Radio Sammanfattning Under åren 2009-2013 har Sveriges Radio digitaliserat sitt programarkiv. Sveriges Radios ambition är att mer material från de 175 000 timmar radio som sänds varje år ska arkiveras. Det är en relativt tidsödande process att göra allt material sökbart och det är långt ifrån säkert att kvaliteten på dessa data är lika hög hos alla objekt.         Frågeställningen som har behandlats för detta examensarbete är: Vilka tekniska lösningar finns för att utveckla ett system åt Sveriges Radio för automatisk igenkänning av svenskt tal till text utifrån deras ljudarkiv?         System inom tal till text har analyserats och undersökts för att ge Sveriges Radio en aktuell sammanställning inom området.         Intervjuer med andra liknande organisationer som arbetar inom området har utförts för att se hur långt de har kommit i sin utveckling av det berörda ämnet.         En litteraturstudie har genomförts på de senare forskningsrapporterna inom taligenkänning för att jämföra vilket system som skulle passa Sveriges Radio behov och krav bäst att gå vidare med.         Det Sveriges Radio bör koncentrera sig på först för att kunna bygga en ASR, Automatic Speech Recognition, är att transkribera sitt ljudmaterial. Där finns det tre alternativ, antingen transkribera själva genom att välja ut ett antal program med olika inriktning för att få en så stor bredd som möjligt på innehållet, gärna med olika talare för att sedan även kunna utveckla vidare för igenkänning av talare. Enklaste sättet är att låta olika yrkeskategorier som lägger in inslagen/programmen i systemet göra det. Andra alternativet är att starta ett liknade projekt som BBC har gjort och ta hjälp av allmänheten. Tredje alternativet är att köpa tjänsten för transkribering.         Mitt råd är att fortsätta utvärdera systemet Kaldi, eftersom det har utvecklats mycket på senaste tiden och verkar vara relativt lätt att utvidga. Även den öppna källkod som Lingsoft använder sig av är intressant att studera vidare. / Speech to text for relevant metadata tagging of audio archive at Sveriges Radio Abstract In the years 2009-2013, Sveriges Radio digitized its program archive. Sveriges Radio's ambition is that more material from the 175 000 hours of radio they broadcast every year should be archived. This is a relatively time-consuming process to make all materials to be searchable and it's far from certain that the quality of the data is equally high on all items.         The issue that has been treated for this thesis is: What opportunities exist to develop a system to Sveriges Radio for Swedish speech to text?         Systems for speech to text has been analyzed and examined to give Sveriges Radio a current overview in this subject.         Interviews with other similar organizations working in the field have been performed to see how far they have come in their development of the concerned subject.         A literature study has been conducted on the recent research reports in speech recognition to compare which system would match Sveriges Radio's needs and requirements best to get on with.         What Sveriges Radio should concentrate at first, in order to build an ASR, Automatic Speech Recognition, is to transcribe their audio material. Where there are three alternatives, either transcribe themselves by selecting a number of programs with different orientations to get such a large width as possible on the content, preferably with different speakers and then also be able to develop further recognition of the speaker. The easiest way is to let different professions who make the features/programs in the system do it. Other option is to start a similar project that the BBC has done and take help of the public. The third option is to buy the service for transcription.         My advice is to continue evaluate the Kaldi system, because it has evolved significantly in recent years and seems to be relatively easy to extend. Also the open-source that Lingsoft uses is interesting to study further.

Den senaste tidens utveckling inom automatisk taligenkänning har lett till mindre resurskrävan-de och mer effektiva modeller. Detta innebär nya möjligheter för forskning kring spontant tal.I den här studien används Kungliga Bibliotekets svenska version av Wav2Vec 2.0 och en tal-korpus skapas utifrån ljudklipp från Sveriges Radio för att undersöka artikulationshastighet ispontant tal. Artikulationshastighet har setts ha en negativ korrelation till informationsdensiteti tidigare studier. Utifrån Uniform Information Density-hypotesens antagande; att talare strävarefter att jämna ut distributionen av information i ett yttrande, undersöks om de sammanlagdadependenslängderna mellan alla huvud och dependenter i meningar är korrelerat med artiku-lationshastigheten. Studien visar att metoden där artikulationshastighet beräknas med hjälp avKB:s Wav2Vec 2.0 leder till systematiskt högre artikulationshastighet än vid en manuell beräk-ning. Samt att korrelationen mellan antal stavelser i ett ord och artikulationshastighet blir denomvända mot vad tidigare studier med manuella metoder visat. Hypotesen att längre depen-denslängd skulle vara relaterat till högre artikulationshastighet får inget stöd i studien. Iställetses en motsatt effekt av minskande artikulationshastighet i relation till ökande dependenslängd.Studien belyser behovet av en modell specialiserad för beräkning av duration för att vidare ut-forska artikulationshastighet genom automatisk taligenkänning. / The last few years progress within automatic speech recognition has led to models that are lessresource demanding and more effective. This means new possibilities in the research regardingspontaneous speech. In this study, KB:s Swedish version of Wav2Vec 2.0 is used to create aspeech corpus and investigate articulation rate in spontaneous speech, with data from SverigesRadio. This study aims to investigate if this is a good method. It has been observed in previousstudies that articulation rate is negatively correlated to information density. With the uniforminformation density hypothesis; that speakers aim to distribute information evenly in an utteran-ce, as a base - this study aims to investigate whether the sum of the word dependency lengths insentences is correlated to articulation rate. The result shows that the method of calculating ar-ticulation rate with KB:s Wav2Vec 2.0 leads to systematically higher articulation rates comparedto results of a manual method. The hypothesis that longer dependency lengths would correlatewith higher articulation rates is not supported in the results. Instead the opposite effect can be  observed. The study shows the need for a model specialized in calculating duration for futureresearch regarding articulation rate with automatic speech recognition.KeywordsASR, automatic speech recognition, UID, articulation rate, dependency length, dependecy mi-nimization, corpus studies, information density

The rise of multilingualism has fueled the demand for computer-assisted pronunciation training (CAPT) systems for language learning, CAPT systems make use of speech technology advancements and offer features such as learner assessment and curriculum management. Mispronunciation detection (MD) is a crucial aspect of CAPT, aimed at identifying and correcting mispronunciations in second language learners’ speech. One of the significant challenges in developing MD models is the limited availability of labeled second-language speech data. To overcome this, the thesis introduces SpeechBlender - a fine-grained data augmentation pipeline designed to generate mispronunciations. The SpeechBlender targets different regions of a phonetic unit and blends raw speech signals through linear interpolation, resulting in erroneous pronunciation instances. This method provides a more effective sample generation compared to traditional cut/paste methods. The thesis explores also the use of pre-trained automatic speech recognition (ASR) systems for mispronunciation detection (MD), and examines various phone-level features that can be extracted from pre-trained ASR models and utilized for MD tasks. An deep neural model was proposed, that enhance the representations of extracted acoustic features combined with positional phoneme embeddings. The efficacy of the augmentation technique is demonstrated through a phone-level pronunciation quality assessment task using only non-native good pronunciation speech data. Our proposed technique achieves state-of-the-art results, with Speechocean762 Dataset [54], on ASR dependent MD models at phoneme level, with a 2.0% gain in Pearson Correlation Coefficient (PCC) compared to the previous state-of-the-art [17]. Additionally, we demonstrate a 5.0% improvement at the phoneme level compared to our baseline. In this thesis, we developed the first Arabic pronunciation learning corpus for Arabic AraVoiceL2 to demonstrate the generality of our proposed model and augmentation technique. We used the corpus to evaluate the effectiveness of our approach in improving mispronunciation detection for non-native Arabic speakers learning. Our experiments showed promising results, with a 4.6% increase in F1-score for the Arabic AraVoiceL2 testset, demonstrating the effectiveness of our model and augmentation technique in improving pronunciation learning for non-native speakers of Arabic. / Den ökande flerspråkigheten har ökat efterfrågan på datorstödda CAPT-system (Computer-assisted pronunciation training) för språkinlärning. CAPT-systemen utnyttjar taltekniska framsteg och erbjuder funktioner som bedömning av inlärare och läroplanshantering. Upptäckt av felaktigt uttal är en viktig aspekt av CAPT som syftar till att identifiera och korrigera felaktiga uttal i andraspråkselevernas tal. En av de stora utmaningarna när det gäller att utveckla MD-modeller är den begränsade tillgången till märkta taldata för andraspråk. För att övervinna detta introduceras SpeechBlender i avhandlingen - en finkornig dataförstärkningspipeline som är utformad för att generera feluttalningar. SpeechBlender är inriktad på olika regioner i en fonetisk enhet och blandar råa talsignaler genom linjär interpolering, vilket resulterar i felaktiga uttalsinstanser. Denna metod ger en effektivare provgenerering jämfört med traditionella cut/paste-metoder. I avhandlingen undersöks användningen av förtränade system för automatisk taligenkänning (ASR) för upptäckt av felaktigt uttal. I avhandlingen undersöks olika funktioner på fonemnivå som kan extraheras från förtränade ASR-modeller och användas för att upptäcka felaktigt uttal. En LSTM-modell föreslogs som förbättrar representationen av extraherade akustiska egenskaper i kombination med positionella foneminbäddningar. Effektiviteten hos förstärkning stekniken demonstreras genom en uppgift för bedömning av uttalskvaliteten på fonemnivå med hjälp av taldata som endast innehåller taldata som inte är av inhemskt ursprung och som ger ett bra uttal, Vår föreslagna teknik uppnår toppresultat med Speechocean762-dataset [54], på ASR-beroende modeller för upptäckt av felaktigt uttal på fonemnivå, med en ökning av Pearsonkorrelationskoefficienten (PCC) med 2,0% jämfört med den tidigare toppnivån [17]. Dessutom visar vi en förbättring på 5,0% på fonemnivå jämfört med vår baslinje. Vi observerade också en ökning av F1-poängen med 4,6% med arabiska AraVoiceL2-testset.

Concrete is the most widely used construction material worldwide, yet, it presents major sustainability drawbacks due to the CO2 released during the manufacturing of its main constituent, cement. Several approaches are used to improve concrete’s eco-efficiency and reduce the binder intensity index, a metric used to measure the eco-efficiency of concrete, to a value below that of conventional concrete mixtures (i.e., 10 kg/m3.MPa-1 for 25-40 MPa mixtures). Particle Packing Models (PPM) is consequently an approach that can be used to enhance system packing density, reducing cement content while increasing hardened state properties and durability (i.e., reducing porosity). However, packed mixtures normally present issues in the fresh state while their hardened state performance is not fully comprehended. Therefore, this Ph.D. project proposes a new mix-design method called PPM-MP approach to develop eco-efficient mixtures. First, a detailed laboratory investigation was conducted on mixtures developed using the proposed approach in order to understand their fresh and hardened state performance. Concrete samples containing distinct ranges of cement content (320, 250, 200, 150 kg/m3) and slump (180, 90, and 20 +/- 20 mm) were fabricated and a wide range of fresh state tests (pH, temperature, fresh density, air content, slump and rheology over time) and hardened state tests (apparent porosity, surface electrical resistivity, compressive strength, and modulus of elasticity) were performed over time. Then, its performance against the alkali-silica reaction (ASR) induced expansion and deterioration, which is one of the leading and most damaging distress mechanisms issues in durability, was evaluated. In this section of the project, four sustainable concrete mixtures developed with varying cement content (e.g., 325, 250, 200, and 150 kg/m3) were developed and compared to a control mixture containing 420 kg/m3 of cement content. The mixtures were tested over a year under Concrete prism test (CPT) setup, which is the current method used to evaluate concrete ASR and using three different non-boosted test setups (i.e., Wrapped - W, Soaked - S, and Encapsulated - E). Moreover, two distinct types of highly reactive aggregates (e.g., Springhill Greywacke coarse aggregate and Texas Polymictic sand) were selected. Microscopic analysis was used to better understand the impact of ASR on sustainable mixtures, as well as the differences in ASR-damage and crack propagation under different test protocols. The results show the feasibility of producing an eco-efficient mixture in a more efficient manner which may contribute to the Net Zero Concrete targets. The proposed PPM-MP approach improves the sustainability of concrete mixtures and can be used for specific projects requiring 28-day compressive strength ranging from 18 to 45 MPa and slumps (180, 90, and 20 +/- 20 mm).

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