For the successful deployment of advanced nuclear systems and for optimization of current reactor designs, high quality and accurate nuclear data are required. Before nuclear data can be used in applications, they are first evaluated, benchmarked against integral experiments and then converted into formats usable for applications. The evaluation process in the past was usually done by using differential experimental data which was then complimented with nuclear model calculations. This trend is fast changing because of increase in computational power and tremendous improvements in nuclear reaction theories over the last decade. Since these model codes are not perfect, they are usually validated against a large set of experimental data. However, since these experiments are themselves not exact, the calculated quantities of model codes such as cross sections, angular distributions etc., contain uncertainties. A major source of uncertainty being the input parameters to these model codes. Since nuclear data are used in reactor transport codes asinput for simulations, the output of transport codes ultimately contain uncertainties due to these data. Quantifying these uncertainties is therefore important for reactor safety assessment and also for deciding where additional efforts could be taken to reduce further, these uncertainties. Until recently, these uncertainties were mostly propagated using the generalized perturbation theory. With the increase in computational power however, more exact methods based on Monte Carlo are now possible. In the Nuclear Research and Consultancy Group (NRG), Petten, the Netherlands, a new method called ’Total Monte carlo (TMC)’ has been developed for nuclear data evaluation and uncertainty propagation. An advantage of this approach is that, it eliminates the use of covariances and the assumption of linearity that is used in the perturbation approach. In this work, we have applied the TMC methodology for assessing the impact of nuclear data uncertainties on reactor macroscopic parameters of the European Lead Cooled Training Reactor (ELECTRA). ELECTRA has been proposed within the GEN-IV initiative within Sweden. As part of the work, the uncertainties of plutonium isotopes and americium within the fuel, uncertainties of the lead isotopes within the coolant and some structural materials of importance have been investigated at the beginning of life. For the actinides, large uncertainties were observed in the k-eff due to Pu-238, 239, 240 nuclear data while for the lead coolant, the uncertainty in the k-eff for all the lead isotopes except for Pb-204 were large with significant contribution coming from Pb-208. The dominant contributions to the uncertainty in the k-eff came from uncertainties in the resonance parameters for Pb-208. Also, before the final product of an evaluation is released, evaluated data are tested against a large set of integral benchmark experiments. Since these benchmarks differ in geometry, type, material composition and neutron spectrum, their selection for specific applications is normally tedious and not straight forward. As a further objective in this thesis, methodologies for benchmark selection based the TMC method have been developed. This method has also been applied for nuclear data uncertainty reduction using integral benchmarks. From the results obtained, it was observed that by including criticality benchmark experiment information using a binary accept/reject method, a 40% and 20% reduction in nuclear data uncertainty in the k-eff was achieved for Pu-239 and Pu-240 respectively for ELECTRA.

The usage of neural networks to derive physical laws without any kind of pre-existing bias is a promising but relatively new field with the long-term goal to construct an artificial intelligence physicist that is able to derive physical laws from experimental data. In this project, a step is taken in the direction of solving complex problems by tackling the double pendulum, the simplest chaotic system. To do so, a neural network architecture, adapted from previous work, is used to find the relevant parameters of the system in multiple configurations of the pendulum. Afterwards, the possibility of a neural network derived general solution of the problem is discussed through the relevant aspects that increase its complexity.

Neutron detectors in the form of liquid organic scintillators are widely used for nuclear disarmament purposes. The main purpose of this thesis is to characterize the neutron detection efficiency of the organic liquid scintillator EJ-309 using Monte Carlo based simulations in the simulation program Geant4. The Monte Carlo simulation code was benchmarked using recorded light output data from a laboratory experiment and it was confirmed that the simulation code could reproduce data from this experiment. In order to characterize the efficiency of the neutron detector, the benchmarked code was used to simulate light output distributions of 241-Am-Be and Cf-252, an (α, n) and a spontaneous fission source respectively, where it was found that the two different types of sources could be distinguished. However, distinguishment between two different spontaneous fission sources was not possible, as simulations of the light output distribution of another spontaneous fission source, Pu-240, was similar to the one for Cf-252. The light output distributions from the simulations were compared to earlier research where good agreements were obtained. A quantitative study was also performed to determine how many detected neutrons were needed to properly be able to distinguish between the two sources 241-Am-Be and Cf-252, and the number was found to be 560. This value was considered low relative to the number of detected neutrons in the simulations, and hence, more quantitative studies are needed in order to verify this result. The absolute and intrinsic detection efficiency were also determined for varying threshold values of neutron energy.

It could be argued that a renaissance is taking place for the global interest in nuclear power - especially for the development of the next generation of reactor systems that aim at solving the problems with contemporary energy production with nuclear technology. One such proposed concept for Gen IV nuclear power is a Molten Salt Reactor (MSR), in which the nuclear fuel is in solution of a salt - often based on fluorine or chlorine. The historical experience of MSRs is limited in both scope and time, but significant developments have been made in the past few years. In order for such technologies to become commercially viable, it is important that investigations are conducted into the behaviour of the materials involved. In this work, the propagation of uncertainty in nuclear data for the isotope F-19 is investigated in a fluorine-based MSR. Uncertainty quantification is important in reactor physics as calculations that are based on Best Estimate Plus Uncertainty often leave more margin to the regulatory requirements compared to conservative calculations. The quantity of interest is the reactivity of the system at hand, and three different levels of moderation were investigated in order to observe any differences that the hardness of the neutron spectrum might impose on the reactivity uncertainty. In addition, the individual neutron-nucleus interaction channels are analyzed separately in order to deduce which channels that contribute the most to the reactivity uncertainty. The nuclear reactor cores were simu- lated with the Monte Carlo-based neutron transport code OpenMC, and the uncertainty quantification was performed using the Total Monte Carlo (TMC) methodology with perturbed nuclear data that was generated using the tools SANDY and NJOY. The results from the uncertainty quantification showed that the nuclear data uncertainty from F-19 gave rise to reactivity uncertainties of approximately 60-200 pcm, depending on the amount of moderation rods that were inserted. The less moderated systems were more susceptible to the F-19 uncertainties, which could be explained by the fact that those systems gave more room for the fluorine- based fuel, and hence they would be more exposed to the uncertainties of F-19. It was also observed that the elastic scattering, neutron capture, and alpha production reaction channels contributed the most to the uncertainties in the most moderated reactor, while the least moderated reactor was most susceptible to the uncertainties due to elastic scattering, inelastic scattering, and alpha production. These findings show that significant improvements needs to be made in the measurements and evaluations of nuclear data for F-19 if it is to be implemented in MSRs of the future. / Intresset för kärnkraft har under de senaste åren utvecklats enormt globalt - särskilt med avseende på utveckling av nästa generation av reaktorsystem som har målen att lösa de problem som finns med dagens energiproduktion via kärnteknik. Ett sådant föreslaget koncept för Fjärde generationens kärnkraft är saltsmältereaktorn (eng. Molten Salt Reactor, MSR), i vilket kärnbränslet är upplöst i reaktorn i ett salt som oftast är baserat på fluor eller klor. Den historiska erfarenheten av MSR:er är knapphändig, men stora framsteg har gjorts under de senaste åren. För att tekniker som denna ska kunna blir kommersiellt genomförbara måste utredningar göras för att förstå hur exempelvis det använda materialet beter sig. I detta arbete propageras osäkerheterna i kärndata för isotopen F-19 genom en fluor-baserad MSR. Os- äkerhetskvantifiering är viktigt i reaktorfysik eftersom beräkningar som är baserade på Bästa Uppskat- tning Plus Osäkerhet (eng. Best Estimate Plus Uncertainty, BEPU) oftast lämnar en större marginal till regulatoriska begräsningar än vad konservativa beräkningar gör. Storheten av intresse i detta ar- bete är reaktiviteten av reaktorhärden, och tre olika nivåer på moderering användes för att kunna observera skillnader i reaktivitetsosäkerheter som orsakas av neutronspektrumets hårdhet. Dessutom undersöktes de individuella reaktionskanalerna för neutron-kärna-interaktioner för att kunna dra en slutsats kring vilka reaktionskanaler som bidrar mest till reaktivitetsosäkerheterna. Reaktorhärdarna simulerades med den Monte Carlo-baserade neutrontransportkoden OpenMC, och osäkerhetskvanti- fieringen gjordes genom Total Monte Carlo (TMC) metodologin med kärndata som genererades med verktygen SANDY och NJOY. Resultaten från osäkerhetskvantifieringen visade att kärndataosäkerheterna från F-19 gav upphov till reaktivitetsosäkerheter på ungefär 60-200 pcm, beroende på vilken modereringsgrad som användes. De mindre modererade systemen var mer mottagliga till osäkerheten hos F-19, vilket skulle kunna förklaras genom att dessa system gav mer plats för det fluor-baserade bränslet, vilket därmed leder till att de är exponerade till osäkerheterna för F-19 i en högre grad. Det observerades också att reaktionskanalerna elastisk spridning, neutroninfång samt alfa-produktion hade stört inverkan på reaktivitetsosäkerheterna för de mest modererade systemen, medan de minst modererade systemen var mer mottagliga till osäkerheterna som orsakades av elastisk spridning, inelastisk spridning och alfa-produktion. Dessa resultat visar att förbättringar måste göras i mätningarna samt evalueringarna av kärndata för F-19 om ämnet ska implementeras i MSR:er i framtiden.

While endocrine disrupting chemicals have become a serious concern in human and environmental toxicology, many of the methods used for investigating developmental toxicity require long exposure periods, and thus can be technically challenging, labour intensive and expensive. For example, the current standard method, the Larval Amphibian Growth and Development Assay (LAGDA) has an exposure period of ³130 days. With the intent of developing a shorter assay for investigating amphibian developmental toxicity, the aim of this study was to characterise effects of the anti-androgenic model substance flutamide on reproductive development in the frog Xenopus tropicalis after a short 16-day post-metamorphosis exposure period using four dose groups: control (C), low (L), medium (M), and high (H) (0, 250, 500 and 1000 µg/L, nominal concentrations, n=58, 19, 39 and 36 respectively). Variations in body morphometry were used to compare C, L, M and H (for which there was no data available on sex ratios) and a random subsample of C (n=15) and H (n=15) individuals were analysed histologically for variation in germ cell maturity, gonadal cross sectional area, Müllerian Duct (MD) length and MD maturity. In addition to these endpoints, concentrations of the anti-Müllerian hormone (AMH), vitellogenin (VTG), oestradiol (E2) and testosterone (T) in the remainder of the body after dissection (normally discarded) for a subsample of C, M and H (N varying between 2 and 11 for AMH, VTG, E2 and T within the dose groups) were investigated with the objective of discovering whether these could be used as viable endpoints using commercially available ELISA kits. Due to random sampling there was an insufficient number of male H dose group individuals to allow for statistical analysis. In females, no significant differences in MD length, MD maturity and gonad size, were seen between the dose groups. No apparent differences in the proportion of mature germ cells in the testis were found, however females in the H dose group were found to have a significantly higher proportion of immature oocytes in the ovaries than C. The ELISA analysis was able to successfully detect AMH, VTG, E2 and T in all three dose groups. Some of the expected interrelationships between bodily AMH, VTG, E2 and T were observed in this study, whereas others were absent and others in direct opposition to prior research, suggesting this method shows promise but requires further study. While no conclusions cannot be drawn with regard to males from this study, effects attributable to flutamide can be detected in females during this dose period, and body homogenate ELISA shows promise for being a viable method but requires further research.

In the Born-Oppenheimer approximation for a quantum system the emergent synthetic magnetic field can be seen as generated by monopoles at points of degeneracy, in full analogue to the synthetic fields generating the geometric phase of adiabatically evolving quantum systems. The plausibility of using these synthetic magnetic monopoles as a means to study magnetic monopole dynamics in the absence of fundamental magnetic monopoles has been explored. A bipartite spin system consisting of a dumbbell translating and rotating through space has been modelled, and full equations of motion in the presence of an external magnetic field have been derived. A collection of scripts for numerical evaluation of these equations of motion were subsequently developed, and further put to use in sample simulations for a small range of parameters. The results demonstrate non-negligible perturbations to the centre of mass motion when compared to motion not considering the Born-Oppenheimer synthetic fields, for dumbbell masses of small but not unrealistic proportions. The problems inherent in this approach to elucidating motion in magnetic monopole fields are discussed, but the method should not yet be dismissed until further investigations have been made. / Under Born-Oppenheimer-approximationen för ett kvantsystem kan det emergenta syntetiska magnetfältet ses som alstrat av monopoler vid degenerationspunkter, helt analogt med de syntetiska fält som genererar den geometriska fasen vid adiabatisk utveckling av kvantsystem. Möjligheten att använda dessa syntetiska magnetiska monopoler för att studera dynamiken från verkan av en magnetisk monopol, trots att fundamentala magnetiska monopoler ej observerats, har utforskats. Ett tvådelat spinsystem beståendes av en hantel som translaterar och roterar genom rummet har modellerats, och fullständiga rörelseekvationer i närvaron av ett yttre magnetfält har härletts. Kod till ändamålet att utvärdera dessa rörelseekvationer har därpå utvecklats, och vidare nyttjats för att simulera rörelsen för ett stickprov av parametrar. Resultaten visar på ej försumbara perturbationer av masscentrums rörelse vid jämförelse med rörelse utan hänsyn till de syntetiska Born-Oppenheimer-fälten, för hantlar av liten men inte orealistiskt liten massa. Problemen och komplikationerna för det här angreppssättet till att utforska rörelse genom magnetiska monopolers fält diskuteras, men metoden bör ej ännu avvisas innan vidare undersökning har genomförts.

Tvångssyndrom eller obsessive-compulsive disorder (OCD) är en kronisk sjukdom vilket präglas av tvångstankar och tvångshandlingar som baseras på ångest. Tvångssyndrom är en produkt av abnormiteter i kortiko-striato-talamo-kortikala (CSTC)-kretsar vilket är associerat med förändring av transmittorsubstanserna serotonin, dopamin, glutamat och γ-aminosmörsyra. Förändringar bland dessa transmittorsubstanser gör att en del substanser får en överaktivitet medan hos andra sker den en drastisk minskning. Det i sin tur leder till hjärnans kapacitet att hantera impulsiva handlingar samt tankar. Tvångstankar är ett återkommande fenomen vilket skapar ofrivilliga tankar och bilder i huvudet, som i sin tur leder till tvångshandlingar och impulser för att lätta på dessa tvångstankar. Tvångssyndrom väcker mycket obehagliga känslor hos individen vilket kan avspegla sig i ångest, äckel, skam eller annat obehag. De flesta patienter som diagnostiserats med tvångssyndrom erbjuds behandling vilket i många fall leder till symptomlindring, mediciner används tillsammans med annan behandling så som kognitiv beteendeterapi. Dock drabbas ungefär 10% av individer med tvångssyndrom av så kallade terapiresistenta symptom vilket betyder att vanlig farmakologisk behandling i samverkan med terapi inte ger någon symptomlindring. På senare tid har det dykt upp djup hjärnstimulering eller deep brain stimulation (DBS) som en alternativ och möjlig behandling för behandlingsresistent tvångssyndrom.  Det specifika syftet med denna litteraturstudie är att undersöka om djup hjärnstimulering är en bra behandlingsmetod för personer behandlingsresistent tvångssyndrom. Av de sex utvalda artiklarna i denna studie konstaterades det att det finns en positiv inverkan på behandlingsresistent tvångssyndrom hos de personer som fått DBS. Artikel 1 studerade området kring gränssnittet mellan BNST/NAcc, Artikel 2 studerade den främ- re delen av Capsula interna, Artikel 3 studerade Capsula interna och nucleus accumbens, Artikel 4 undersökte DBS påverkar PPI, Artikel 5 kollade på den ventrala främre extremiteten av Capsula interna och ventrala striatum och artikel 6 undersökte djup hjärnstimulering som ett sista behandlingsalternativ till kapsulotomi vid behandlingsrefraktär tvångssyndrom Alla artiklar visade på förbättring hos de individer som medverkat i de respektive studierna. Det påvisades stora förändringar hos vissa medan andra hade en mindre påverkan, dock var alla positiva till de förändringar som djup hjänstimulering bidragit till. Samtliga visade på en minskning i Y-BOCS under samt efter behandling. Kunskapen om djup hjänstimulering kring behandlingsresistent tvångssyndrom är idag begränsad, det gör att resultaten i sin tur inte ger en större generell bild om det fungerar eller inte. För att kunna ge en så bra och effektiv behandling som möjligt behövs det mer forskning på området. / Obsessive-compulsive disorder (OCD) is a chronic disease characterized by obsessions and compulsions based on anxiety. The obsessive-compulsive disorder is a product of abnormalities in cortico-striatal-thalamocortical (CSTC) circuits, which is associated with changes in the transmitters of serotonin, dopamine, glutamate, and γ-aminobutyric acid. Changes in levels of these transmitter substances cause imbalances that results in dysfunctional neurotransmission. As a result, this leads to the brain's incapacity to han- dle impulsive actions and thoughts. Obsessive-compulsive disorder is a recurring phe- nomenon that creates involuntary thoughts and images in the brain, leading to compulsive actions and impulses to alleviate these obsessive-compulsive disorders. Obsessive- compulsive disorder evokes very unpleasant feelings in the individual, which can be reflected in anxiety, disgust, shame, or other discomforts. Most patients diagnosed with obsessive-compulsive disorder are offered pharmacological treatment, which in many cases leads to symptom relief. Medications are, in many cases, used together with other treatments such as cognitive-behavioral therapy. How- ever, approximately 10% of individuals with the obsessive-compulsive disorder suffer from so-called therapy-resistant symptoms, which means that standard pharmacological treatment in combination with therapy does not provide any relief of symptoms. Recently, deep brain stimulation or deep brain stimulation (DBS) has emerged as an alternative and possible treatment for treatment-resistant obsessive-compulsive disorder.  The more specific purpose of this literature study is to investigate whether deep brain stimulation has a suitable treatment method for people with treatment-resistant obses- sive-compulsive disorder. Of the six selected articles in this study, it was found that there is a positive effect on treatment-resistant obsessive-compulsive disorder in the people who received DBS. Article 1 studied the area around the interface between BNST / NAcc, Article 2 studied the anterior part of the Capsula internal, Article 3 studied the Capsula internal and nucleus accumbens, and Article 4 examined DBS affects on PPI. Article 5 examined the ventral anterior extremity of the Capsula internal and ventral striatum, and article 6 examined deep brain stimulation as a last resort alternative to capsulotomy in treatment-refractory obsessive-compulsive disorder. All articles showed improvement in the individuals who participated in the respective studies. Significant changes were shown in some while others had a minor effect. However, all were positive about the changes that deep brain stimulation contributed. All showed a decrease in Y-BOCS during and after treatment. The knowledge about deep brain stimulation around treatment-resistant obsessive-compulsive disorder is currently limited, which means that the results, in turn, do not give a more extensive general picture of whether it works or not. In order to provide as good and effective treatment as possible, more research is needed in the area.

Using and finding applications from biomass is and will continue to be an important subject forresearch, and biomass from trees, has shown several outstanding aspects other than just for the pulpand paper applications. It is now, more than ever, time to find efficient uses for all the woodcomponents, in particular, the hemicelluloses. The hemicelluloses account for approximately onethirdof a dry composition of lignocellulosic wood biomasses. Of these hemicelluloses, xylan is themost abundant in many plants, particularly in hardwood. As for the Swedish forestry, xylan frombirch is considered as one of the most promising resources for the future.This thesis investigates the impact of acetylation of xylan on some properties such as solubility,thermal stability and film formation. Films were prepared using the non- and acetylated xylan withaddition of different plasticizers (glycerol, sorbitol and xylitol).Alkali-soluble birch xylan (ASX), obtained by ethanol/toluene extraction and sodium chloritedelignification of the wood sawdust followed by potassium hydroxide extraction of the obtainedholocellulose, and commercial xylan (CX) were acetylated to different degree of substitution withacetyl groups (DSAc), using acetic anhydride in dimethyl sulfoxide (DMSO) and 1-methylimidazole(NMI). Films were prepared by suspending non-acetylated xylan in water (H2O) and adding differentpercentages of plasticizers (20 and 40%) or by suspending acetylated xylan in chloroform (CHCl3).Characterizations of the non- and acetylated polymer (AcASX and AcCX) and films were conducted inorder to determine thermal and mechanical properties.CX and ASX presented different reactivity leading to different behaviour during acetylation and sodifferent DSAc. The thermal stability has been improved for both ASX and CX following the increase ofthe DSAc. Concerning film formation, ASX showed a great ability to form films through casting with orwithout plasticizers while it was impossible to obtain any films using only CX. For AcASX and AcCX thefilm formation using chloroform was depending on the DSAc and the dispersability in the solvent. Allthe films obtained have been mechanically and thermally tested. Best results for the mechanicaltests were obtained with 40% plasticizers with creation of a plastic behaviour and improvement ofthe flexibility. Thermally speaking, the thermal stability gained through acetylation of the samples islost by film casting, and use of plasticizers reduced the thermal stability as a new component wasadded to the composition. / Att använda och hitta tillämpningar från biomassa är och kommer att fortsätta att vara ett viktigtämne för forskning, och biomassa från träd har visat flera goda aspekter annat än bara för massaochpappersapplikationer. Det är hög tid att hitta effektiva användningar för alla träkomponenter, isynnerhet hemicelluloserna. Hemicelluloserna står för ungefär en tredjedel av en torrsammansättning av lignocellulosa. Av dessa hemicellulosor är xylan den vanligaste i många växter,särskilt i lövträ. När det gäller det svenska skogsbruket anses xylan från björk vara en av de mestlovande resurserna för framtiden.Denna avhandling undersöker effekterna av acetylering av xylan på vissa egenskaper, såsomlöslighet, termisk stabilitet och filmbildning. Filmer framställdes med användning av den icke-ochacetylerade xylanen med tillsats av olika mjukningsmedel (glycerol, sorbitol och xylitol).Alkalöslöslig björkxylan (ASX), erhållen genom etanol / toluenutvinning och natriumkloritfördelningav träsågspån följt av kaliumhydroxidutvinning av erhållen holocellulosa och kommersiell xylan (CX)acetylerades till olika grad av substitution med acetylgrupper (DSAc), med användning avättiksyraanhydrid i dimetylsulfoxid (DMSO) och 1-metylimidazol (NMI). Filmer framställdes genom attsuspendera icke-acetylerad xylan i vatten (H2O) och tillsätta olika procentdelar mjukningsmedel (20och 40%) eller genom att suspendera acetylerad xylan i kloroform (CHCI3). Karakteriseringar av denicke-och acetylerade polymeren (AcASX och AcCX) och filmer utfördes för bestämning av te rmiskaoch mekaniska egenskaper.CX och ASX presenterade olika reaktivitet vilket ledde till olika beteenden under acetylering och såolika DSAc. Den termiska stabiliteten har förbättrats för både ASX och CX efter ökningen av DSAc. Närdet gäller filmbildning uppvisade ASX en stor förmåga att bilda filmer genom gjutning med eller utanmjukningsmedel medan det var omöjligt att erhålla några filmer med endast CX. För AcASX och AcCXvar filmbildningen med användning av kloroform beroende av DSAc och dispergerbarheten ilösningsmedlet. Alla filmer som erhållits har testats mekaniskt och termiskt. Bästa resultat för demekaniska testerna erhölls med 40% mjukningsmedel med skapandet av ett plastiskt beteende ochförbättring av flexibiliteten. Termiskt sett förloras den termiska stabiliteten som erhållits genomacetylering av proverna genom filmgjutning, och användning av mjukningsmedel reducerade dentermiska stabiliteten som en ny komponent tillsattes till kompositionen.

The cleaning technology for exhaust air is an area under constant development. In collaboration with Ozone Tech Systems the project resulted in a lab scale test rig for air cleaning units. The test rig was designed primarily to investigate the mechanisms of an UV reactor as well as the life times of a hydrogen sulphide absorption bed and an activated carbon bed. The thesis consisted in the design of the system, the acquisition of units and the construction of the system followed by the modelling of the pollutant elimination in the UV reactor. Fluid dynamics of the process flow is neglected, while the light distribution is numerically calculated. Two separate pollutants were considered, one being volatile organic compounds represented by acetaldehyde, and the other being hydrogen sulphide, chosen due to their prevalence in exhausts. An experimental plan is developed to validate the model, find model parameters and finally to investigate process parameters in the UV reactor. / Luftföroreningar är ett mycket aktuellt problem, och tekniken för att rena luftströmmar är under ständig utveckling. I samarbete med Ozone Tech Systems designades och byggdes en testrigg för att undersöka olika luftreningsenheter. De primära målen var att undersöka mekanismerna i en UV reaktor samt livslängden för två lika packade bäddar; en absorptionsbädd för divätesulfid samt en adsorptionsbädd av aktiverat kol. Examensarbetet bestod av designmomentet, införskaffande av rätt enheter och konstruktionen av systemet. Även numerisk modellering av UV-reaktorn ingick i projektet, och denna gjordes med störst avseende på UV-ljusets fördelning i reaktorn medan flödesdynamiken försummades.Två olika föroreningar valdes p. g. a. deras frekventa förekomst i luftströmmar som ska renas; divätesulfid och flyktiga organiska ämnen (representerade här av acetaldehyd). Rapporten presenterar även en experimentell plan för att validera modellen, hitta modellens semiempiriska parametrar, samt till slut för att med hjälp av faktoriell design undersöka interaktionen mellan olika faktorer i UV-reaktorn.

As the mission to the decrease global warming and phase out highly pollutingenvironmental practices globally, regulations including Euro 6 and policies generated by theUnited Nations Framework Convention on Climate Change (UNFCCC) are pushing companiesto be more innovative when it comes to their energy sources. These regulations involve manyfactors related to the cleanliness of the fuel and produced emissions, for example, propertiesof the fuels such as sulfur content, ash content, water content, and resulting emission valuesof Carbon dioxide (CO2) and Nitrogen Oxides (NOx). Furthermore, Sweden has set achallenging target of a fossil-fuel-independent vehicle fleet by 2030 and no net greenhousegasemissions by 2050.One way to cut down on the polluting properties in the fuel, as well as weakening thedependence on fossil fuel based fuel includes utilizing higher blending ratios of biofuels in thetransport sector. This transition to biofuels comes with many challenges to the transportindustry due to higher concentrations of these new fuels leads to clogging of the filters in theengine, as well as, internal diesel injector deposits (IDIDs) that produce injector fouling. Thisclogging of the filters leads to lower performance by the engines which leads to higher repairtimes (uptime) and less time on the road to transport goods. The formation of these softparticles at the root of the clogging issue is a pivotal issue because the precise mechanismsbehind their formation are highly unknown. Scania, a leader in the Swedish automotiveindustry, is very interested in figuring out what mechanisms are the most influential in theformation of these particles in the engine. Understanding the key mechanisms would allowScania to make appropriate adjustments to the fuel or the engines to ensure more time onthe road and less maintenance.There are many conditions known to be possible causes of the formation of softparticles in engines such as water content, ash content, and temperature. After generatingsoft particles using a modified accelerated method, particles were analyzed using infraredtechnology (RTX-FTIR) and a Scanning Electric Microscope (SEM-EDX). Many differentexperiments were performed to be able to make a conclusion as to which mechanisms weremost influential including temperature, time, water, air, and oil. The combination of agingbiofuels (B100, B10, HVO) with metals, and water produced the largest amount of particlesfollowed by aging the biofuels with aged oil, metals, and water. Aging the fuels with aged oilincreased particles, meanwhile the addition of water prevented particle production possiblydue to additives. B100 produced the highest amount of particles when aged with Copper, B10with Brass, and HVO with Iron.