No description available.

The annual increase in waste car tires in addition to the enormous amount at present poses a major waste management problem as well as an environmental hazard. However, pyrolysis is emerging as a solution for waste tire management and a viable technology for material recycling and energy recovery that produces high energy liquid and gas products as well as char. The pyrolysis oil that is produced from this technology has the potential to be used as vehicle fuel but contains exceeding levels of sulfur and other impurities. This study investigates the upgrading and desulfurization of waste tire pyrolysis oil by reactive adsorption using a molybdenum modified zeolite and its desilicated form. The experiments were performed at 320 °C and a LHSV of 45-50 h-1 for approximately 45 min, and revealed that both desilication and Mo-modification resulted in the cracking of both gaseous and liquids compounds, reduction of TAN, denitrogenation, and deoxygenation. Desilication increased desulfurization while Mo-modification increased the EHI. The treatment was the most effective in the removal of oxygen, followed by nitrogen and sulfur. In conclusion, the treatment process is promising as a method for direct liquid upgrading but requires further research.

The study has been conducted in collaboration with Swestep AB, a Swedish company that specializes in the conversion of waste to valuable products via the KDV technology. The study explores the possibility of using cassava chips and cassava pulp as a potential feedstock in the production of synthetic diesel and compares the KDV method with fermentation, a conventional method of using cassava chips and cassava pulp in Thailand. To obtain the carbon yield, amount of product and system efficiency, a mass and energy balances were first performed on wood feedstock data provided by the company. The balances were thereafter used as a basis for a simulation analysis of the cassava feedstock. The diesel product yield is produced through a KDV 150 plant using 551kg/h of the different feedstock; wood, cassava chips and cassava pulp resulting in different amounts of diesel product 150 L/h, 116.79 L/h and 121.31 L/h, respectively. For cassava, the C yield in diesel is 0.41 while the C yield of ethanol production is 0.14, since C in the ethanol production is converted into other matters. Besides, the system efficiency of the KDV plant with different types of feedstock is around 0.84 because some parts of the KDV plant is self-supplied whereas the ethanol production plant (55% of system efficiency) is not. Economical evaluations of the KDV 5000 and ethanol production plant were performed. The KDV 5000 with cassava pulp as feedstock produces 31 ML/year and is feasible for investment in Thailand due to the low price of the feedstock which is driving the operation cost (15.167 baht/L or 0.46 USD/L). This is lower than the selling price (21.329 baht/L or 0.65 USD/L) whereas the KDV 5000 plant with cassava chips is not feasible. The KDV plant with cassava pulp as a feedstock will reach the breakeven point after running for 7 years. The ethanol production process with cassava chip as feedstock produces 49 M liter/year and has an operation cost of 19.693 baht/liter (0.6 USD/L) which is higher than the KDV plant due to the feedstock price. The selling price of ethanol is 23.11 baht/l (0.705 USD/L) which resulted in the process reaching the breakeven point after 14 years.

Sveriges riksdag har tagit fram 16 miljömål där ett av dem ämnar att minska övergödningen isvenska sjöar och vattendrag. Övergödning är bland annat ett resultat från näringsämnen somläckt från jordbruk. En lösning på övergödningsproblemet skulle kunna vara att samla upp deläckta näringsämnena och återföra dem till åkern. Detta skulle kunna göras med hjälp av biokolsom adsorbent och syftet med detta projekt är att undersöka dessa möjligheter samt biokoletsstruktur. Definitionen på biokol är att det är en heterogen kolliknande substans från hållbart framtagenbiomassa. Den ska även ha ett högt kolinnehåll och användas på ett sådant sätt att den binderupp kolet under en längre tid. Biokol framställs genom pyrolys eller förgasning under högtemperatur och syrefattiga förhållanden. Syftet med användande av biokol som adsorbent ärmöjligheten att kunna skapa ett kretslopp. Biokolet ska först verka som filter i avrinningsdikenvid åkermark för att sedan återföras, mättad med näringsämnen, tillbaka till åkermarken. Vid experimenten användes tre olika kol. Ett grillkol och två olika biokol. Strukturen på deolika kolen undersöktes med en BET-analys. Analysen av grillkolen gav ett orimligt svar menför de två biokolen gavs resultat som ansågs rimliga. Denna analys ger inte ett direkt värde påadsorptionsförmåga hos kolen utan behöver verifieras med ett experimentellt framtagetsamband mellan struktur och adsorptionsförmåga. Ett alternativ till BET-analysen är att göraen jodnummeranalys, som ger värden på adsorptionsförmåga för det undersökta ämnet. Denna analys utfördes inte praktiskt. Två lösningar med olika koncentrationer av Na3PO4 förbereddes och blandades underomrörning med de olika kolen. Två olika omrörningstider användes för att kunna undersökauppehållstidens betydelse. Efter omrörning filtrerades proverna för att få bort kol och de olikafiltraten genomgick en ICP-analys för undersökning av fosforinnehåll. Resultatet som framkomav denna analys var att filtraten hade en högre fosforhalt än vad de initiala lösningarna hade.Förklaringen till detta antas vara att biokolet redan innehöll fosforföreningar som Na3PO4 ut. Problemet med ICP-analysen var att den inte kunde detektera i vilken form fosforn var.Det gick heller inte att detektera kväve i ICP-analysen då luften runt omkringinstrumentet innehåller kväve vilken kontaminerar provet och detekteras i analysen. Enalternativ metod till ICP är att använda spektroskopi som dels kan detektera kväve men ävenolika former av fosfor- och kväveföreningar. Slutsatsen var att analys av biokols adsorptionsförmåga är att den är komplex. BET-analys ären bra metod för att visa struktur på kolen men jodnummer kan vara ett bättre alternativ för attdirekt hitta ett värde på kolets adsorptionsförmåga. För analys av lösningar fungerar ICP enbartför fosfor och därför skulle spektroskopi kunna vara ett bättre alternativ då det kan detekterakväve samt olika former av föreningar. / The aim of this project is to create a deeper understanding of biochar’s ability to adsorbnutrients. In the long run the aim is to find a way to use the most suitable structures of biocharfor a maximum adsorption of different kinds of nutrients. The objective of this project is tofind, through case studies and practical experiments, an effective method to examine andanalyze the structure of biochars and their ability to adsorb nitrates and phosphates. The conclusion of the project was that analysis of the biochar’s ability to adsorb is a complexmatter. The BET-analysis is a good method to find the structure of the biochar. However, iodinenumber analysis could be a better alternative to directly find a value on the biochar’s ability toadsorb. The ICP-analysis of the solutions only works for phosphor, therefore spectroscopywould be a better alternative since it also can detect nitrogen and the different compounds.

Geometric Quantum Computation (GQC) is one of the effective methods to realizequantum computation. By using geometric phases, it shows robustness to certainerrors. This thesis aims to develop a new systematic technique for implementing GQC,especially in non-adiabatic systems. First, we examine the nature of the geometric phasewith differential geometry. Then, we give a general theoretical method to realize a givenquantum gate with a geometric phase through reverse engineering. We examine themethod in the constant frequency quantum system with 2 or 3 energy levels. Finally, weanalyze the non-Abelian case where some of the frequencies are degenerate. / Geometrisk kvantberäkning (GQC) är en av de effektiva metoderna för att förverkligakvantberäkningar. Genom att använda geometriska faser visar den sig vara robustmot vissa fel. Syftet med denna avhandling är att utveckla en ny systematisk teknikför att genomföra GQC, särskilt i icke-adiabatiska system. Först undersöker vi dengeometriska fasens natur. med hjälp av differentiell geometri. Därefter ger vi en allmänteoretisk metod för att realisera en given kvantgrind med en geometrisk fas genomreverse engineering. Vi undersöker metoden i kvantsystemet med konstant frekvensoch med 2 eller 3 energinivåer. Slutligen analyserar vi det icke-Abeliska fallet där vissaav frekvenserna är degenererade.

A number of animal species have undergone domestication, the process of becoming adapted to living in captivity and in proximity to humans. Common for these species is that they have all developed certain traits, including changes to coat color, body size and level of fearfulness. This has been termed the domestic phenotype. Among these traits is also an attenuation of the response to stress, both behaviorally and physiologically. Thus, release of glucocorticoids such as cortisol or corticosterone is lower in domesticated species. However, the underlying mechanism for this is not yet well understood. In this thesis, we have investigated genetic mechanisms for the attenuation of the physiological stress response in ancestral chickens, the Red Junglefowl, and domesticated chickens, the White Leghorn. We found a number of genes that differed in expression between the two breeds in several tissues involved in the stress response. Among the most interesting findings were lower expression of genes involved in production and secretion of ACTH in the pituitary, and in the production of glucocorticoids in the adrenal glands, in the domesticated White Leghorns. We also found higher expression of the glucocorticoid receptor in White Leghorns, indicating that they may have a more efficient negative feedback of the physiological stress response. We then investigated the transcriptome of the chicken pituitary more closely, and we discovered that a number of genes highly involved in several important physiological axes showed differential expression between the ancestral and the domesticated breed. Among these were genes involved in the stress response, the reproductive system, and in metabolism and growth. As these traits are modified in domesticated species, our results suggest that changes to gene expression in the pituitary may be an important underlying factor of the domestic phenotype. A separate aim of this thesis was to investigate effects of hatching time in chickens on their subsequent phenotype. Time of hatching constitutes an early experience that may differ between individuals, and we therefore hypothesized that differences in hatching time would affect chickens later in life. While a number of studies have been performed on hatching time and post-hatch growth, very little work has been done on effects on behavior. We found that the time of hatching had sex-specific effects. Hatching times in females were negatively correlated with body weight, whereas in males, behaviors such as reaction to novelty and spatial learning were affected. As time of hatching is governed by various hormones, including thyroid hormone and corticosterone, we suggest that changes to the levels of these hormones could affect both hatching time and post-hatch phenotypes. Understanding these mechanisms better would be beneficial in terms of production, where batch homogeneity is important, in research on early experiences and the potential for maternal programming, and in evolutionary questions on trade-off between different life strategies.

This thesis aimed to look at the behaviours of the water beneath waves from a modeling and simulations point of view. We have investigated how to use Linear wave theory (LWT) to model the kinematic movements in water governed by free ocean waves. The model assumes the surface to consist of a superposition of sinusoidal waves. We have used fast Fourier transform (FFT) to move the surface waves from the space domain to the frequency domain from which we used the components to transform back with the inverses described by LWT. We recreated the surface with the expression for surface elevation for both two and three dimensions, and compared to the original surface. Then the same transformed components could be used to calculate the velocity fields beneath the surface. We found that the recreated surface aligns with the original surface in two and three dimensions. For the three dimensional surface we also found that the error is larger on the peaks of the waves and that at the boundary where the surface ends the error is significant due to some implementation error which we disregard. The calculated velocity fields has the expected circular movement over time and it decreases with depth. We found that a surface described with few discrete points significantly overestimates the velocities close to the surface. By increasing the number of points on the surface with simple linear interpolation this issue was resolved. The algorithms used to calculated the inverse transforms had complexity Ο(N) where N is the number of points for which to calculate the velocity, and the FFT has complexity Ο(N log N) where N is the amount of points that the surface consists of. The performance test seems to follow this trend. For applications of the methodology some future work is advised. Firstly the velocities need to be compared to some data to validate the method. Secondly some further time needs to be spent on the three dimensional case to verify that that the velocity fields behave properly and that the cross sections match with the two dimensional case. And finally, we apprehended an issue on which wavenumber to use for each wave component. Since the positive and negative wavenumber is possible and determines the propagation direction of that wave, we need to find a way to make sure that we are using the correct one for each wave component of an unknown surface.

No description available.

The thesis focuses on the application of force measurements with atomic force microscopy (AFM) on materials with a few surface contacts/asperities and chemically modified surfaces. The technique allows measurements of ultra-small intermolecular and surface forces, down to the piconewton level. The force measurements between surfaces of well-defined geometry are often used to measure and model the interaction between different systems of charged and neutral surfaces in various environments. However, detailed knowledge of the contacting surface profile geometry and surface properties is required to model the fundamental forces involved in the interaction. The preparation of such well-defined and idealized surfaces is often time consuming and the surfaces may not possess the behavior and properties of a source material in real processes, such as in industry. Moreover, external factors such as magnetic fields, ionic strengths and pH-values in a solution, may further complicate the evaluation. Hence, it is desirable to explore and develop techniques for trustable measurements of forces between “real” surfaces. These are often a complex composition of various force interactions and multiple surface contacts.The AFM probe technique was explored to measure force interactions between “real” particle surfaces. The work shows the applicability of the AFM technique to study the interaction forces despite the forecasted difficulties with the roughness of the particles.A technique to measure the adhesion and work of adhesion from AFM force curves was implemented and used. The thermal tune method was implemented in our commercial NT-MDT microscope to determine cantilever spring constants. The force interactions between natural microsize (m-s) magnetite particles and synthetic nanosize (n-s) magnetite particles were studied in calcium solution with concentrations of 1, 10, 100 mM and at pH values 4, 6 and 10. The changes in force interactions, due to variations in calcium concentration and pH were investigated. The adhesion force change with the concentration and pH was similar for m-s/m-s and m-s/n-s systems, and the adhesion force increased with the concentration at pH 6, except for the highest calcium concentration of 100 mM at pH 10. It was found that the magnetite surface modification could appear at the highest calcium concentration at pH 10. Moreover, the thesis contains preliminary results of the force interaction study between natural and synthetic bentonite-magnetite particles in calcium solution with concentrations of 1, 10 and 100 mM at pH 6.The influence of roughness on the calculation of contact mechanics parameters were studied with AFM and Vertical Scanning Interferometry (VSI). This is important for future development of a model to describe and characterize the force interaction between samples with multiple surface contacts. It was found that the optical artifacts, induced by VSI, have a large influence on all the roughness parameters calculated on the calibration grids, which represent extreme surface topographies.

Carbon nanotubes (CNTs) have attracted attention over the past decade because of their outstanding mechanical and electronic properties. These tiny tubular shells made of carbon atoms can be metallic or semiconducting and while having diameters of only about one nanometer (10-9 m), they can be up to centimeters in length, making them quasi one-dimensional (molecular wires). Along with a Young's modulus several times that of steel, CNTs are close to perfect (ballistic) electric conductors and conduct heat better than diamond. This makes them candidates for a variety of applications from nanoscale electronics and composites reinforced with CNTs on the molecular level to nano-actuators and high performance flatscreen displays.Beside electron microscopy, no other experimental method has been employed more in research on carbon nanotubes than Raman spectroscopy since it can noninvasively probe single CNTs and provide direct information about their molecular properties, for example, diameter and chirality. That is possible because in the case of CNTs Raman scattering is resonantly enhanced, giving an increase in signal by a factor of 106. Due to their high surface energy and the van der Waals inter-tube interactions, carbon nanotubes naturally form bundles of up to hundreds of tubes. Heat dissipation in CNT bundles is inefficient and, as a result, their exposure to high incident laser power causes overheating and results in several thermal effects dominating the Raman spectrum. The high cost of CNT production has strongly impeded design of "pure nanotube" functional materials, thus shifting the focus of CNT materials research to creation of CNT-based composites. Such new multifunctional materials, based on the outstanding physical properties of nanotubes, are created by mixing relatively small amounts of CNTs with polymers or metals (matrix). This is still a big challenge because of poor dispersion of CNT bundles in the matrix and weak bonding of the nanotubes to the surrounding host (matrix) molecules. One proposed solution to solve the latter problem is to establish bonding of CNTs to the matrix via functional groups covalently attached to the CNT surface, i.e., to use so-called "functionalized" CNTs in composites.The aim of this work is to explore the possibilities of using Raman spectroscopy for expressive characterization of functionalized CNTs, the source material for synthesis of CNT-based composites. CNTs produced by two synthesis techniques, with different diameter distributions, were probed using several laser excitations. Evaluating the efficiency of the functionalization process requires first determination of the intrinsic spectroscopic properties of the pristine (non-functionalized) CNTs. Because functionalization is carried out on bundled CNTs, a detailed investigation of whether the incident laser irradiation causes thermal effects in the sample during Raman experiments was performed in order to find experimental protocols for recording the intrinsic (unperturbed by heating) spectrum of the CNT bundles. From this study a set of "reference conditions" defining laser irradiance levels that do not result in overheating of the CNT bundles was established. Exceeding these laser irradiation levels (thresholds) first results in reversible changes of the Raman spectrum due to heating, while further increase of the laser irradiation leads to irreversible changes in the spectra and, hence, destruction of the CNTs in the sample. Evaluation of this destruction demonstrates its dependence on CNT diameter and high sensitivity to photon energy. Additional experiments show that in some cases a similar instability of the Raman spectra and irreversible destruction of the CNTs occur at laser irradiation levels below those that increase sample temperature. Finally, we used the "reference" laser irradiation regimes to characterize the effects of CNT sidewall functionalization. Specifically, HiPCO-produced, single-walled CNTs functionalized by methoxypenyl functional groups were studied in detail and the influence on the three main vibrational bands investigated. Results from analysis of the radial breathing mode band show that the functionalization process is selective and depends on both nanotube diameter and type.