Global warming is now widely recognized as being the biggest global issue facing human beings. Mitigating CO2 emission from fossil-fueled power plants as well as from transports has become an urgent and worldwide research topic, in which CO2 separation is often needed. Technologies have been developed and commercialized, whereas the cost is still high. Developing new technologies for CO2 separation is one focus research area. Ionic liquids (ILs) are promising absorbents for CO2 separation due to their very low vapor pressure, high solubility and selectivity for CO2 as well as low energy usage for solvent regeneration. To develop IL-based technologies, thermodynamic properties (density, heat capacity, gas solubility, etc.), viscosity, and surface tension of ILs are the prerequisites. As the number of ILs that can be theoretically synthesized is up to an order of 1018, determining all the properties experimentally is impractical, not to mention the time-consuming with high cost. It is desirable to develop theoretical tools to predict the thermodynamics and transport properties of ILs and IL-containing mixtures in a wide temperature and pressure range. In our previous work, the framework of ion-specific electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) has been developed with reliable results. However, the work is still limited to the imidazolium-based ILs, and the model performance for other commonly used ILs is still unclear. Meanwhile, it has been pointed out that the model with the parameters fitted to the experimental data may result in pitfalls, and further validation is needed. In this thesis, the ion-specific ePC-SAFT was further developed and extended to the ILs which are composed of the IL-cations ([Cnmim]+ , [Cnpy]+ , [Cnmpy] + , [Cnmpyr]+ , and [THTDP]+ ) and the IL-anions ([Tf2N]- , [PF6] - , [BF4] - , [tfo]- , [DCA]- , [SCN]- , [C1SO4] - , [C2SO4] - , [eFAP]- , Cl- , [Ac]- , and Br- ). Before modeling the properties, a method and scheme were developed to investigate the pitfall when modeling IL with ePC-SAFT. All 96 ILs considered in the thesis were covered. The investigation shows that for most ILs (86 of 96 ILs), the additional fictitious critical temperature is low enough not to affect the calculations at a normal temperature range, and after further phase equilibrium calculation, only one IL ([C8mpy][BF4]) may generate a risk of pitfall occurrence at the temperature and pressure of interest for CO2 separation. The parameters for [Cnmpy]+ may need to be modified in future work. The prediction of the derivative properties (isobaric heat capacity, isochoric heat capacity, speed of sound, isentropic compressibility coefficient, isothermal compressibility coefficient, thermal expansion coefficient, thermal pressure coefficient, and internal pressure) combined with the comparison to the available experimental data shows that ePC-SAFT can provide reliable results for most ILs. ePC-SAFT was used to predict the CO2 solubilities in 46 ILs, and the prediction agrees well with the experimental data in a wide temperature and pressure range for 36 ILs. The addition of an ion-specific binary ii parameter between IL-ion and CO2 can further improve the model performance significantly for the 10 ILs with relatively poor model performance. ePC-SAFT can also provide a reliable prediction for the solubility of other pure gases (CH4, CO, H2, N2, and O2). To further verify the model performance on the viscosity of ILs, ePC-SAFT coupled with the free volume theory (FVT) (i.e., ePC-SAFT-FVT) was studied. Two strategies were applied to adjust the FVT parameters, i.e., molecular-based approach with parameters for each IL (strategy 1) and IL-cation molecular-weight linearized parameters for the ILs in the same homologous series (strategy 2). The comparison with the available experimental viscosities for 96 ILs shows that the strategy 1 can provide reliable results for 89 ILs in a wide temperature and pressure range, while strategy 2 can provide almost similar reliable results as strategy 1. ePC-SAFT-FVT can be further used to predict the viscosity of ILmixtures reliably. The model ePC-SAFT-DGT, i.e., the coupling of ePC-SAFT with the density gradient theory (DGT), was further developed and used to model the interfacial properties of ILs. The comparison with the available experimental surface tensions for 82 ILs shows that the model can represent the surface tension reliably, and the use of the anion-specific influence parameters linearized with the molecular weights of IL-cations allows predicting the surface tension of the ILs in the same homologous series. The density profile on the vaporliquid interface can be further predicted with the influence parameter adjusted by the surface tension. In summary, the ion-specific ePC-SAFT is a suitable tool for IL-systems, which can be highly recommended to be applied in industrial design and optimization.

This project focuses on the numerical modeling of a rotary kiln pyrolyzer such as found in the e.g. WoodRoll multistage gasification process. The model consists of two parts: a granular flow model, and a pyrolyzer model. In the first part, Saeman's equation was employed to develop a model which can describe the behavior of solid granular flow in a rotary kiln without reaction. Residence-time distribution (RTD) is the main aim to study in this part, which was simulated by axial dispersion model (ADM). The model requires only one fitting parameter that is dispersion coefficient (Dax), which was studied in parallel by two cases: constant value of Dax, and Dax as a function of kiln's length. The result of both models show good predictable in comparison to experimental data from literature, and represent narrow distribution of residence times that behave similar to plug flow reactor. Unfortunately, the result still cannot claim which model of Dax is the best model to describe RTD in rotary drum. The second part of the thesis purpose to design the model of rotary kiln pyrolyzer, which contains specific behavior of granular flow, heat transport in a kiln, and primary pyrolysis of wood. The model of steady-state condition with constant wall temperature was simulated to generate temperature profile and conversion along a kiln. This model included all heat transport features such as conduction, convection, and radiation. According to the result, supplied energy from outer surface of the kiln essentially transfer through the kiln via heat conduction, which occur between solid bed and rotating surface of the kiln. Temperature profile that generated by this model looks reasonable to the process of rotary kiln pyrolyzer, which affected by heating system and heat of reaction along the kiln. The result also demonstrated that conversion of wood is strongly dependent of wall temperature or heating rate of the system. Nonetheless, kinetics data for wood pyrolysis still a debatable issue in many research, and this model required validation by experiment of rotary kiln pyrolyzer.

The aim of this thesis was to investigate the influence of aqueous radiation induced oxidants on stainless steel. This was done by exposing the steel to both radiation and chemically added oxidants under ambient conditions, i.e. in and near room temperature. When water is exposed to radiation several oxidizing species are formed, including hydrogen peroxide, which have been known to increase the risk for corrosion of other materials. Stainless steel is used in many parts in a nuclear power plant, and the results from this thesis could be useful when elucidating whether the steel is an appropriate material to use for these applications.

Manufacturing of paper is a large industry in Sweden. At Hallsta paper mill dithionite is used to bleach the thermo mechanical pulp (TMP) at their production line 12. The purpose of this work was to minimize the addition of dithionite while maintaining the brightness of the produced paper. In order to achieve this goal three different dosages, high, medium and low dosage, were used at the first dosage points. Furthermore, the working conditions were examined by measuring SO2 along the production line to verify that the levels were according to the national guidelines. To evaluate the brightness of the pulp along line 12, pulp was collected at eight different sites of sample withdrawal and made into test paper. The brightness of the test paper was measured with a spectrophotometer. The levels of SO2 were measured at various points of interest using a multi gas meter. Results show that the total amount of dithionite used was lower when a lower dosage at the first dosage points was used. The brightness gain was approximately the same for all dosages. According to this study, the strategy of dosage should be chosen in relation to the wood received. The high dosage at the first dosage points was an unnecessarily high dosage for the recieved wood. The dosage at the later dosage points should be chosen with respect to the brightness goal of the produced paper. The measurements of SO2 show no relation with dosage of dithionite at the first dosage points, because of a large uncertainty. Further improvements on the working environment must be applied at the critical stages in the production line.

Two possible ways for increasing the rate of separation for magnetic bead separation has been observed. Increasing NP concentration by 2.5x gave a slight increase in rate of separation while 1.5x and 2.0x concentration increase resulted in a slight decrease in rate of separation. Synthesizing the magnetic beads under the influence of an external magnetic field also showed promising results. In a literature review, several types of magnetic beads and technologies are discussed, and how there is a great future potential for magnetic beads in the isolation of several types of biomolecules. It is concluded that the market for magnetic beads for cell isolation is expanding greatly with many different applications and expects to be worth 14.64 billion USD by 2025.

Mängden öl som köps i Sverige har ökat mellan åren 2016–2021. Både försäljningen av öl med en alkoholhalt över 3,5 procent (starköl), och öl under 3,5% (lätt- och folköl) ökade betydligt. Utbudet av lätt- och folköl är avsevärt mer begränsat än det av öl med starkare alkoholhalt, och i takt med att fler väljer att dricka lätt- och alkoholfri öl så bör en marknad finnas som kan svara på det. Det är vanligt att öl endast ses som en berusningsdryck vilket är något denna rapport menar att säga emot. Öl innehåller en stor mängd proteiner, polyfenoler och andra vitaminer som är bra för hälsan, men den höga alkoholhalten i starkare öl tar bort många av ölens positiva effekter. I detta kandidatexamensarbete har en ny sorts öl tagit fram vilket har fått namnet Teknikringen 2,1. Det är en mörk veteöl, vilken är en ölsort som ökar i popularitet bland de alkoholstarka ölsorterna, men som inte finns som varken alkoholfri, lätt- eller folköl. Målet med arbetet var att ta fram en ny produkt som inte finns på den svenska marknaden och ge den möjligheten att fylla ett hål för människor som är trötta på att konsumera hög alkoholhaltiga drycker. Utöver att beskriva bryggningsprocessen undersöker arbetet kostnaderna och kraven som ställs på nystartade mikrobryggerier, samt den slutgiltiga smakprofilen som ölen får. Det är en mörk veteöl med en alkoholhalt på 2,1% och ett energiinnehåll på 25 kcal/100 ml som framställs. Ölen har en låg alkoholhalt samt ett energiinnehåll som är under genomsnittet för en vanlig lättöl. / The amount of beer purchased in Sweden has increased between the years 2016-2021. Both the sales of beer with an alcohol content above 3.5 percent (strong beer) or below 3.5 percent (light and low-alcohol beer) have significantly increased. The availability of light and low-alcohol beer is considerably more limited compared to beer with higher alcohol content. As more people choose to drink light and alcohol-free beer, there should be a market that can meet that demand. It is common for beer to be seen solely as an intoxicating beverage, which is something this report argues against. Beer contains a large amount of protein, polyphenols and other vitamins that are health beneficial, but the high alcohol content in stronger beer diminishes many of beer's positive effects. In this bachelor’s thesis a new type of beer has been developed, named Teknikringen 2,1. It is a dark wheat beer, which is a beer style that has increased in popularity among beers with high alcohol content but is not available as alcohol-free, light, or low-alcohol beer. The aim of the project was to create a new product that is not available in the Swedish market and provide it with the opportunity to fill a gap for people tired of consuming high-alcohol beverages. In addition to describing the brewing process, the work also examines the costs and requirements imposed on newly established microbreweries as well as the final flavor profile that the beer achieves. It is a dark wheat beer with an alcohol content of 2.1 percent and an energy content of 25 kcal/100 ml. The beer has a low alcohol content and below-average energy content compared to a regular light beer.

<p>Flotation is a critical operation in the isolation of valuable minerals from natural ore. Before flotation, chemical collectors are routinely added to ground ore slurries. Collectors selectively bind to mineral-rich particles, increasing their hydrophobicity thus promoting selective flotation. Conventional collectors are small surfactants with a short hydrocarbon tail (2-6 carbons) and a head group, such as xanthate. In this work, much larger hydrophobic polystyrene nanoparticles are evaluated as potential flotation collectors. Experiments involving both clean model mineral suspensions and complex ultramafic nickel ores confirm that conventional water-soluble molecular collectors could be partially or completely replaced by colloidal hydrophobic nanoparticle flotation collectors.</p> <p>The ability of nanoparticles to induce flotation has been demonstrated by floating hydrophilic, negatively charged glass beads with cationic polystyrene nanoparticle collectors. Mechanisms and key parameters such as nanoparticle hydrophobicity and nanoparticle adsorption density have been identified. Electrostatic attraction promotes the spontaneous deposition of the nanoparticles on the glass surfaces raising the effective contact angle to facilitate the adhesion of beads to air bubbles. The pull-off force required to detach a glass sphere from the air/water interface of a bubble into the water was measured by micromechanics. Coating with nanoparticles allows the beads to attach remarkably firmly on the air bubble. As little as 10% coverage of the bead surfaces with the most effective nanoparticles could promote high flotation efficiencies, whereas conventional molecular collector requires 25% or higher coverage for a good recovery. Contact angle measurements of modified glass surfaces with a series of nanoparticles that covered a range of surface energies were used to correlate the nanoparticle surface properties with their ability to promote flotation of glass beads. Factors influencing nanoparticle deposition on glass, such as nanoparticle dosage, nanoparticle size, conditioning time have been investigated with a quartz crystal microbalance (QCM). Deposition kinetics has been analyzed according to Langmuir kinetics model.</p> <p>Surface functionalized nanoparticles enhance the ability of nanoparticle collectors to selectively deposit onto surfaces of the desired mineral particles in the presence of gangue materials. Poly (styrene-co-vinylimidazole) based nanoparticle collectors have been developed to selectively deposit onto nickel mineral (pentlandite) in the presence of Mg/Si slime. Flotation tests of ultramafic nickel ores with these nanoparticle collectors have shown improvements in both pentlandite recovery and selectivity.</p> / Doctor of Philosophy (PhD)

<p>This thesis describes solutions to many of the challenges in the development of paper-based biosensors. Coupling techniques in analytical biochemistry with knowledge of paper science and technology, advances are described in the areas of: the influence of paper surface chemistry on bioactivity; optimizing bioactive ink formulation; the printing of paper supported microfluidic channels; and, the characterization of complex sensors based on printed sol-gel material layers.</p> <p>The stability of paper-immobilized antibodies under various conditions was first studied using both untreated filter paper and PAE-treated paper. Antibody stability decreased with increasing temperature and relative humidity. Paper treated with PAE had no significant influence on antibody stability under the experimental conditions. The experimental result was also encapsulated in an empirical equation to predict the impact of printing and coating operations on antibody activity.</p> <p>The influence of paper sizing agent (AKD) on the adsorption and inactivation of antibody was also investigated. The preliminary study showed that the small amount of AKD improved the antibody adsorption on paper and also did not interfere antibody activity. Therefore, packaging papers containing sizing agents can be used as a substrate for antibody immobilization.</p> <p>Two strategies to fabricate hydrophobic barriers were developed, based on sol-gel derived MSQ material. The first method is based on ink-jet printing a highly basic solution onto MSQ-impregnated filter paper to re-exposing the cellulose and producing a hydrophilic patterned region. The second method is direct ink-jet printing of MSQ onto paper to outline the hydrophobic walls bordering the hydrophilic channels. The resistance of the barriers to surfactants and organic solvents was tested. The functionality of MSQ-based devices was further demonstrated by using a colorimetric assay for <em>E. coli </em>detection.</p> <p>Multiple-stage inkjet printing of sol-gel based bioink onto porous filter paper for enzyme immobilization was characterized by various methods. Confocal microscope and SEM/TEM images confirmed the formation of sol-gel and enzyme composite material on the paper fibers without cracking. The protease assay proved that the entrapment of enzyme molecules improved with the increasing amount of the sol-gel derived material printed on paper. The top layer of sol-gel ink was found to play a major role in protection against enzyme proteolysis, while the bottom layer of sol-gel ink was found to be necessary to prevent the potential inhibition of enzyme by the cationic polymer.</p> / Doctor of Philosophy (PhD)

<p>Many practical fluid flows involve liquid-particle systems and so there is a need to better understand the mechanism of particle deposition, adhesion, and agglomeration in suspensions, especially in complex geometries with moving boundaries and free surfaces. In this thesis, the nature of the particle-solid interactions and particle-fluid interactions is studied where the above complexities are present, taking into account particle collision, colloidal, and hydrodynamic forces, and two way coupling between the fluid flow and particles. The research is motivated by the industrial examples of: flow of dross particles near the sink roll surface in a galvanizing bath (moving surface), and the flow of particles in slot coating dies (free and moving surfaces). Particle motion and agglomeration play important roles in the example systems chosen for this fundamental 3-D study. Numerical studies of flow of dispersed suspensions makes it possible to understand the effects of flow conditions, particle characteristics, and flow geometry specifications that lead to agglomeration of particles in complex systems, especially where experimental studies are difficult to perform. Often the effects of these conditions are discovered due to process or product failures, rather than through insight into the processing steps.</p> <p>The modeling methodology used in this work is that micron sized spherical particles are tracked in the fluid phase by solution of Newton`s second law of motion for each particle. Fluid phase applies hydrodynamic forces on particles (drag, lift). Body forces, (soft sphere) particle-particle collisions and particle-wall collisions are considered. Particle concentrations are in the dilute regime between 0.01-5%vol. Flow of particles with the fluid phase is a fully coupled formulation in systems with particle concentrations > 1%vol.</p> <p>The thesis is organized around three example problems taken from industry that pose challenging modeling issues. The first involves particle collisions with a moving wall (dross particles in a zinc bath). The second problem includes particle-particle and particle-wall collisions in a turning flow geometry. The third problem, particle dispersion flows in a slot coating die, has the most complexity and includes particle-particle, particle-wall and free surfaces.</p> <p>Dross particle build up on the sink roll inside the zinc bath is an industrial problem that causes significant down time, and where an experimental study of the molten zinc in a bath running at C is difficult to perform. With the aid of computational fluid dynamics, turbulent flow of molten zinc in galvanizing bath is simulated, compared with previous cold model experiments, and coupled with the motion of dross particles around the sink roll. The presence of fixed position hardware and moving sink roll and guide rolls in a bath with dimensions in the orders of meters, and micron sized (20-100 ) dross particles makes this case a complex study. Drag, buoyancy, lift force and soft sphere nonlinear collision is considered in solution of Newton`s law of motion for each particle. Turbulent flow is simulated using a standard model. Simulations show regions on the sink roll where particles are dragged toward the surface of sink roll and have long residence times. These regions have been reported to experience large particle build-ups in the hot-dip galvanizing process.</p> <p>In another study, formation and breakage of agglomerates in a turning flow is studied. Neutrally buoyant particles with concentration of 5%vol are tracked in a fully coupled flow. Particles form agglomerates at the corner, where drag and lift force from the fluid breaks a number of agglomerates. The presence of a moving wall in the turning flow shifts the suspended particle formations toward the inside of channel. Location of particles agglomerates shifts toward the free surface with the presence of free surface at the turning flow.</p> <p>Motion of micron sized spherical particles with 1-4%vol through a slot die coating system is elucidated in a separate study. The system is complex with presence of moving web and free surface. Discrete element method (DEM) for motion of dispersed phase and volume of fluid (VOF) method for solution of continuous phase are integrated in a simulation study. Particles are 2-4 and the flow dimensions of the system are in the order of 100 . Particles experience collision, colloidal and hydrodynamic forces. Coupling between flow of particles and fluid phase is conducted. The results of this study show particle positions on the coating film can be predefined and depends on their initial positions within the feed slot. Particles agglomerate in recirculating regions of the coating gap and follow the streamlines of flow on the moving web. Regions in the coating gap where particles have high residence times (inside the die and near the feed slot edges) have particle agglomerations in the slot die coating system.</p> / Doctor of Philosophy (PhD)

In a 2D cell culture, the cells are mainly grown on flat surfaces which are usually made of polystyrene plastic. Cells are able to attach to these surfaces, forming individual cell formations or colonies. In this study, we have been looked at many different platforms to improve cell growth, adhesion, attachment and proliferation on two different promising cell lines. These cell lines are the human neural stem cells (hNSCs) and human liver hepatocellular carcinoma cells (HepG2). Researchers have been very interested in studying these cell lines in the recent years as they have very useful potentials in the long run to aid and cure many of the disorders, diseases and possibly replace infected or injured organs as well. This can be done using actual clinical applications for cell therapies and tissue transplantation. Based on the studies conducted for this thesis, we have been able to show that cells can be maintained in a 2D culture setting with increasing growth and adhesion factors. The conditions used for these studies were a way to not use the traditional materials for cell attachment and growth. This was pursued due to the fact that most stem cells for their continuity require a microenvironment that will support their physical and chemical properties of an effective extra cellular matrix (ECM). To reiterate, presently most ECM molecules are human or animal derived for effective cell culture applications but not clinical. This is a major problem as each batch varies, they are difficult to isolate and most contain biological components that have been known to limit their use in clinical applications. Hence, this study concentrated on developing synthetic polymer based ECMs as they do not have the problems of the human or animal derived ECMs, but also as they are relatively low-cost, reliable and easily fabricated. Through many experimental trials we have successfully developed synthetic polymer based ECM molecules that sustain stem cell growth for HepG2 liver hepatocellular carcinoma and hNSC human neural stem cell lines. The different substrates developed were a peptide fabricated in our lab; different concentrations and solutions of Poly 4-vinylphenol (P4VP) that were used on a flat hollow fiber membrane made using Polyacrylonitrile (PAN) doped in a solution containing PAN/N, N-dimethylformamide (DMF) having a high biocompatibility. This hollow fiber membrane study was maintained with eight different conditions over a period of 6 weeks.