Ozone treatment of pollutants in air is a relatively young technology with limited literature available. To the authors knowledge no literature discussing simulations of commercial ozone treatment without UV-lamps in gas phase has been published up to this point.The purpose of this project was to identify issues and propose recommendations related to the distribution of ozone in industrial ducting and the injection of ozone into commercial ducting. The injection rate of the ozone mixture is small relative to the flow of the treated air stream. In such cases ozone is easily swept away and confined to a limited section of the ducts, affecting overall efficiency. The injection inlet and ducting were simulated together in both 2D and 3D environments using COMSOL Multi-physics with CFD, CAD and transport of diluted species modules.Improving mixing in industrial ducting was simple in comparison to the commercial ducting where the flow is complex. For the commercial application simulations showed that the mixing efficiency varies greatly between injection positions. Based on CFD data in the commercial ducting two models for injection point analysis were developed.2D and 3D simulations showed different result for injections inside the main duct, the 3D case could properly simulate rotating flows inside the main duct which makes certain injection points in the main duct more effective that predicted in 2D.This master thesis project was done in cooperation between Royal Institute of Technology and Ozonetech in Sweden.

National and international comparisons have emphasized mathematics in recent years. For example, several studies (OCED, 2012) show that students in both Europe and the United States, have difficulty achieving in mathematics. Consequently, attention has turned to preschools. The Swedish government believes that the preschool has not made full use of children’s desire to learn (Cabinet Office, 2010). According to Tallberg-Broman (2012), there is a paradigm shift today in Sweden. A new vision of children, parenting and the school’s mission is emerging. Preschool teachers have to help children meet an increasingly complex reality now and in the future so the requirements of preschool teachers’ professional skills have likewise increased (Persson & Tallberg-Broman, 2002). In my study, I intend to focus on preschool teachers’ transformation of the mathematical goals specified in the revised curriculum for preschool. By analyzing how preschool teachers talk about the revised mathematics objectives and how they are transformed into practice can provide, this study can provide valuable information about how mathematics is visible in the preschool.

The interactions between the divalent salts CaCl2, MnCl2 and NiCl2 with the carboxylicacid groups in an arachidic acid Langmuir monolayer are studied using vibrational sumfrequency spectroscopy (VSFS). At low salt concentrations the charging of the monolayer is shown to behave in accordance with classical theories of the electrical doublelayer. However, deviations from classical theories are readily apparent at concentrations starting from 1 μM and shown to differ depending on the nature of the cation, indicating an ion specific effect. From the analysis of the carboxylate symmetric vibration at least two different types of ion pair interactions between the divalent cations and the carboxylicacid moiety are detected: a solvent-separated and two (or more) possible contact ion-pairs and/or complexes. By using different VSFS polarization schemes the molecular orientation of the vibration is elucidated and further insight into the state of the carboxylic acidis gained. The ordering of water molecules in the diffuse layer as a result of the surfacepotential of the charged monolayer is also probed and found, at low ionic strengths, to bein agreement with the behaviour predicted by the Gouy-Chapman model. At high concentrations the hydration within the Stern layer can be detected and found to differ with the nature of the electrolyte. Additionally, the importance of the purity grade of the salts used for correctly interpreting the results is shown theoretically and verified experimentally,where trivalent ions affect the surface at concentrations several orders of magnitude below those from mono and divalent ions. Finally, diffusion is shown to play a major rolein the kinetics of deprotonation of the monolayer at submicromolar concentrations, while higher valency cations are also shown to deprotonate the surface at a quicker rate through electroflux.

The wet-end of the centre ply of the paperboard machine n˚ 2 (“Kartongmaskin 2” or KM2) inIggesund was simulated to obtain both qualitative and quantitative results on its start-up dynamics andits variation damping capacity. The accuracy of the model was controlled by comparing the simulationresults with data from the real production process. Furthermore, alternative strategies with theobjective of reducing the time needed for start-ups and grade changes were evaluated.The modeling was done using the Paperfront simulation software. Variables such as layout for themixing system, retention level and amplitude and period of inlet concentration were used asparameters. As alternative operation strategies for start-up and grade change, increased flowrate in theearly phase of a start-up and the temporary overdosing during the beginning of a stock change wereevaluated.The results indicate a strong control of the mixing system over the short circulation both in dynamicsat start-up and in general operation with a time constant for the machine close to 35 minutes. Inaddition, variations in consistency are more easily controlled by a double-chest mixing system and, ingeneral, variations are more easily damped the higher the active volume in the mixing system. Finally,times needed for start-up and composition changes could be reduced by as much as 50% by using amore proactive approach.

The strive for cutting out of a fossil-fuels dependence of countries' economies has driven the global research into developing more sustainable powersources with the ultimate target to completely liberate from coal-red and nuclear power plants. Shifting energy policies to renewable energy resourcesundoubtedly carries many benecial features, but also poses a range of technical challenges, such as the necessity to overcome large uctuations in the energy output from wind or photo-voltaic farms.One solution to this problem proposed in the 1970's is to integrate a large-scale energy storage device such as redox- ow batteries into the electrical grid. The thesis rst presents a brief overview of ow battery technology and applications. Next, a one-dimensional, steady-state, macrohomogeneous mathematical model of a hydrogen-bromine ow battery is developed, described and solved. The results are in good agreement with existing experimental data. Moreover, a parametric study is performed to examine the impact of selected parameters on the overall performance of a single cell. A complete set of eld variable plots is explicitly presented.

In this thesis project, treatment of municipal wastewater using ultrafiltration is evaluated to investigate ways to prevent or minimize fouling from occurring. The aim of this project is to examine which factors play a significant role in causing different types of fouling, in order to minimize the resulting effect and thereby increase the efficiency and lifetime of the membrane. The project started with a broad literature study, which researched which methods are currently used to treat wastewater on an industrial level and other state-of-the-art solutions that are available. This was then used to form an experimental plan where two membranes were tested using a pilot plant constructed at IVL’s research facility Hammarby Sjöstadsverk. Firstly, a polymeric membrane was tested using different pressures to see the influence on the membrane flux. The results indicated that although a higher pressure lead to higher flux, there is an upper limit for the flux that was achieved at 5 bar, since similar flux values were found at 5 bar, 7 bar and 9 bar. Also, though a higher flux did lead to a more rapid decrease in flux initially, all curves plateaued after approximately 40 minutes. An average recovery of the membrane flux capacity was 88.7%, where the highest one was achieved with a pressure of 7 bar. Secondly, a ceramic membrane was tested using a factorial design with three parameters, each having a low and high setting. The parameters that were tested were the total operating time, the pressure and the cleaning time of the membrane, with the aim to investigate how each parameter influenced the fouling and the removal of organic compounds from the wastewater. The fouling was analyzed by measuring the flux across the membrane and showed mixed results. Fouling could be removed and the flux often had a recovery of 100% or more, however, no clear conclusion could be drawn to which parameter was the most influential for this high removal percentage. As for the removal of organic compounds, an average removal of 66.9% was achieved and it was determined that the cleaning time was the most influential parameter, and the interaction between running time and pressure being the second most influential.

Pretreatment of biomass plays an important role in IGCC processes. Optimized operating conditions improve overall process eciency, product diversity and producergas composition. This project focuses on the pretreatment of spruce woodbiomass using high pressure superheated steam in a packed bed reactor with heated walls. The objective is to optimize the operation for ecient energy consumption and uniform thermal treatment of wood particles along the reactor. For this purpose,two models have been developed: Single-phase superheated steam in porous media where local thermal nonequilibrium condition prevails, Multi-phase ow in porous media.The rst model investigates the essential parameters to be taken into accountto ensure a uniform thermal treatment as the pyrolytic agent i.e. steam exchanges heat with solid particles. It is found that solid matrix and steam reach thermalequilibrium at early stages of the process however, sharp decrease in uid temperatureis observed. This trend is believed to be aected mostly by uid inlet velocity and solid initial temperature. The model suggests that the initial solid temperaturedoes not play an important role compared to the uid inlet velocity.The focus of the second model is optimization of reactor heat source to avoidthe complications attributed by a two-phase ow. The model can predict the phasesaturation of uid in the porous media along with the pressure and velocity prolesfor a given inlet ow condition and reactor heating power. A reactor with heatsource localized at the inlet is recommended to satisfy the thermal requirements ofthe system.Steam treatment of biomass at elevated pressures is a novel technology whichis believed to bring about many advantages for IGCC process. However, detailed optimization is necessary to benet from these advantages.

In this study, the development of a cellulose-based membrane for use in Vanadium Redox Flow Cell Batteries (VRFBs) was investigated. Cellulose is the most abundant biopolymer on earth and due to its versatility it finds multiple applications. However, cellulose and its derivatives can be easily hydrolyzed in the amorphous regions, under acidic conditions. In order to bypass this problem and use this tough material in the highly acidic and oxidative environment of a VRFB, two approaches were utilized. First, cellulose nanocrystals (CNCs) were employed, which basically lack amorphous regions, to minimize the effect of hydrolysis. An additional advantage is that CNCs can create films with specific stereochemistry, as they pack closely, in helical structures. Second, the surface of the CNCs was modified with the use of trichloro(1H,1H,2H,2H- perfluorooctyl)silane (TCPOS). This molecule has a long fluorocarbon chain, which acts protectively towards hydrolysis of the CNCs. The choice of silane was made in order to produce a material that can resemble Nafion, the most popular copolymer used in VRFBs. Nafion has a fluorocarbon, Teflon-like, backbone and a hydrophilic side chain that consists of a sulfonic acid groups. The first step was to make a material that is stable under the VRFB conditions. The membranes were characterized with AFM imaging, FTIR spectroscopy, contact angle measurements, and tensile testing. With the use of the product of alkoxylation of TCPOS (TMPOS), hydrophobic membranes were produced that exhibit contact angle with water larger than that of Nafion. Young’s modulus of the membranes with TMPOS was larger compared to the one of CNC membranes without TMPOS. To determine stability against acidic conditions, Dynamic Light Scattering (DLS) was used. Additionally, stability of the membranes after acid and Vanadium solution treatment was performed with gravimetric measurements. From the results, 67% of the samples tested remained intact under high ionic strength and acidic conditions. In addition, the effect of the amount of silane on the membranes was evaluated. The results of this study are promising and encourages further research on this direction. / I denna studie undersöktes utvecklingen av ett cellulosabaserat membran för användning i Vanadin redoxflödesbatterier (VRFB, en.). Cellulosa är den mest förekommande biopolymeren på jorden och med dess mångsidighet finns många tillämpningar. Cellulosa, och dess derivat, kan dessvärre enkelt hydrolyseras i amorfa regioner under sura förhållanden. För att kringgå detta problem och för att kunna använda materialet i den sura och oxidativa miljö som förekommer i ett VRFB, användes två tillvägagångssätt. Först användes cellulosananokristaller (CNC, en.) för att minimera effekten av hydrolys, då de huvudsakligen saknar amorfa regioner. Ytterligare en fördel är att man med CNC kan skapa filmer med specifik stereokemi, då de packas tätt i spiralformade strukturer. Det andra tillvägagångssättet var att modifiera CNC-ytan med hjälp av trikloro(1H,1H,2H,2H-perfluoroktyl)silan (TCPOS, en.). Denna molekyl har en lång fluorvätekedja, som skyddar mot hydrolys av CNC. Silan valdes för att skapa ett material som liknar Nafion, som är den vanligaste co-polymeren i VRFB. Nafion har en huvudkedja av fluorväte, liknande Teflon, och en hydrofil sidokedja bestående av sulfonsyragrupper. Det första steget var att göra ett material som är stabilt under de förhållanden som råder i ett VRFB. Membranen karaktäriserades med hjälp av AFM, FTIR-spektroskopi, kontaktvinkelmätningar och dragprov. Alkoxyleringsprodukten som erhölls ifrån TCPOS- behandlingen användes för att tillverka hydrofoba membran med en kontaktvinkel mot vatten som är större än för Nafion. Youngs modul för membran med TMPOS var större än för CNC- membran utan TMPOS. För att klarlägga stabiliteten under sura förhållanden ändvändes DLS. Dessutom testades membranens stabilitet efter syra- och vanadinlösningsbehandling genom olika gravimetriska mätningar. Resultaten visade att 67 % av de testade proverna förblev intakta under förhållanden med hög jonstyrka och surhet. Effekten av mängden använt silan i membranen utvärderades också. Resultaten från denna studie är lovande och uppmuntrar till vidare forskning i denna riktning.

Polymer electrolyte fuel cells (PEMFC) convert chemical energy into electrical energy with high energy efficiency. Air-breathing PEMFC is a type of fuel cell suited for portable application owing to certain properties such as light weight and low operating temperature. The performance of the fuel cells can be improved by optimizing the temperature and pressure. Temperature directly influences the water management and the rate of oxygen reduction, whereas pressure, due to clamping of the cell, acts as one of the main dominant characters in the performance of the cell in the case of air-breathing PEMFC. The main goal of this thesis was to study the effect on performance of using different geometrical areas of the GDL (electrode area).The polarization results for the entire set of cells showed an increasing trend with higher electrode areas. The effect of clamping pressure was observed to be one of the dominant parameters when the performance curve was plotted for potential vs current density. This might be due gas distribution along the surface of the electrodes. The choice of gasket thickness in the cell assembly also showed a performance difference for cells of same electrode area

För att behandla ammoniumrikt lakvatten från två äldre deponietapper med icke farligt avfall på Löt avfallsanläggning byggde SÖRAB en anläggning för kontinuerlig biologisk rening (KBR). Trots god nitrifikation har avskiljning av kväve inte varit fullständig i denitrifikationssteget utom under perioder fosforsyra tillsatts till processen. Under dessa perioder har dock fosforhalten blivit för hög, vilket har lett till problem med gällande utsläppsvillkor. För att utreda om fosforsyratillsatts är nödvändig samt studera det mikrobiella samhället och ge förslag på förbättring har den aktuella reningen och faktorer som kan ha påverkat den undersökts. Detta har gjorts med hjälp av kemisk analysdata från 2015-2017, in vitro odling och mikroskopiakttagelser kombinerat med FISH-analys. De faktorer som beaktades, var temperatur, konkurrens och halten av tungmetaller, nitrat, nitrit, substrat och syrgas. Fokus låg på de faktorer som i dagsläget går att styra i KBR-anläggningen samt förmodas vara mest kritiska.Under projektperioden 2017 var flödet lägre än vad KBR-anläggningen var designad för och uppehållstiden var ca 95 dagar. Vid analys av data från 2015-2017 noterades att reningen tål ned till 10 C° men kommer inte igång ordentligt förrän vid ca 16 C° efter avstannad drift. Biotillgänglig fosfor var begränsande för denitrifikationen under 2017 samt att halten fosfatfosfor som tas upp i denitrifikationen alltid återkom i efterföljande reningssteg. F.I.S.H-analys gav svårtolkade resultat med få organismer och mycket partiklar. Mikroskopstudier och in vitro odling på agarplattor indikerade en ökning i antal organismer över projekttiden (mars-juni 2017), samt att många protozoer var flagellater och detta indikerar att reningen var under uppstart. Antalet filamentösa bakterier stor, vilket kan bidra till skumning tillsammans med exkreterade sackarider.Fosfatfosforhaltens ökning i reningsstegen efter denitrifikationssteget kan bero på att celler dör då vis näring blir begränsande samt nedbrytning av biomassa blir större än dess uppbyggnad. Det gick inte att fastställa fosforackumulerande bakteriers påverkan på halten fosfatfosfor. I framtiden kan den fosfortillsats som behövs bestämmas utifrån slammängden (VSS, Volatile Suspended Solids). Ett annat förbättringsförslag är att lakvattnet kan ledas in i denitrifikationssteget först, alternativt kan lakvattnet recirkuleras mellan nitrifikationssteget och denitrifikationssteget. / In order to treat the ammonium rich leachate formed in two of the older landfills for non-hazardous waste at Löt avfallsanläggning SÖRAB built a continuous biological treatment plant (KBR). The nitrification has been total except for shorter periods during the startup of the process. However the denitrification was not complete except during periods when phosphoric acid was added to the treatment step. When adding phosphoric acid the phosphorus content in the water became too high and risked to exceed the standards for emitting treated leachate from the facility. To evaluate the need for addition of phosphoric acid in the treatment process, analysis of nutrients, in vitro cultivation of microorganisms, microscopic observations and FISH analysis was conducted from March to May 2017. The factors considered in this report were the temperature, some toxic substances such as heavy metals, nitrates, competition between organisms and phosphate depletion. Extra focus was put on the factors that can be controlled and were thought to be most critical.The composition of the leachate that comes from Löt avfallsanläggning’s old landfills is similar to many other leachate. The time it takes to start the biological processes is long but not unusual for similar treatment plants. By 2017, the inlet flow to the KBR was less than what the KBR was designed for, and consequently the residence time for the leakage water in the KBR was approximately 95 days. When analyzing data from previous years it was noted that the treatment worked down to 10 °C but would not start properly until the temperature reached about 16 °C after a stop in operation during the cold months. It was clear that bioavailable phosphorus was limiting the denitrification in 2017 and that the same level of phosphate taken up in the denitrification always reoccurred in later steps. FISH analysis yielded unclear results with few organisms and many particles. This does not rule out that denitrifying bacteria or phosphor accumulating bacteria exist in the plant but gave no definitive answer. Microscopic studies and in vitro cultivation on nutrient agar plates indicated an increase in the number of organisms over the time of the project (March to May 2017) and presence of many protozoa with flagella suggested that the treatment plant was in a startup stage. A number of filamentous bacteria was also observed, which could contribute to foaming together with storage of polysaccharides.The increase in phosphate concentration in the final treatment steps may be due to lysis of cells and biomass degradation, but the influence of phosphorus accumulating bacteria cannot be ruled out. In the future, to overcome the problem of excess phosphorus in the effluent, the required phosphorus additive can be determined based on the sludge volume (VSS, Volatile Suspended Solids). The leachate can be recirculated back to the denitrification step, alternately; the inlet leachate can be redirected to enter the denitrification step first.