Engineered nanoparticles (NPs) are produced in increased quantities. Due to this increase, itis vital to understand the full lifecycle and fate of these NPs to prevent any possible environmental stress. As a result of their size, NPs may interact differently with their environment compared to bulk materials with the same composition, this both gives NPs their usage as well as risks. The risks often include unwanted interaction with biological systems which may lead to generation of toxicity. This study focused on environmental transformations of manganese and manganese oxide (Mn3O4) NPs. Applications these nanoparticles are often in battery technology and catalysis. A solution intended to mimic  the composition of freshwater was used as the environmental media to study these transformations. Exposure of NPs was performed both with and without added natural organic matter (NOM). Several experiments were preformed such as Atomic absorption spectroscopy (AAS) for dissolution of the NPs, Nanoparticle Tracking Analysis (NTA) for particle size, and Attenuated total reflection Fourier transform infrared spectroscopy (ATR- FTIR) for adsorption studies. The production of reactive oxygen species (ROS) was also investigated, and simulations of metal speciation using Visual MINTEQ were also performed. The results from NTA and AAS (for Mn3O4) were not very reliable due to inconsistencies in the results which were probably caused by problems with preparation. However, for both, the results point towards that the dissolution rates of the particles are slightly slowed down when NOM is added. From ATR-FTIR and the simulations it was confirmed that NOM, carbonate, and sulfur will adsorb onto both particles, possibly in multiple layers. As for increased ROS development, no evidence of such an increase was found. However, the method used does not test for increased hydrogen peroxide development so this would in interesting test as well. Other studies which also would contribute to a more nuanced picture of this system is studies regarding zeta potential and studies which furtherinvestigates the type of adsorption mechanism which occurs at the particles surface. / Industriella nanopartiklar används i allt större utsträckning. Därför är det av stor vikt attundersöka hela livscykeln som dessa produkter går igenom for att säkerhetsställa att de inte utgör någon fara för miljön och ekosystemen som de kan komma att hamna i. Som ett resultat av deras storlek interagerar nanopartiklar annorlunda med sin omgivning om man jämför med bulkmaterial av samma sammansättning, detta nanopartiklar både sina unika fördelar och risker. Riskerna innefattar ofta oönskade interaktioner med biologiska  kretslopp som kan resultera i toxicitet. I den här rapporten läggs fokus på just denna typ av kemiska omvandlingar som nanopartiklar av mangan och manganoxid kan tänkas genomgå i det naturliga kretsloppet. Applikationer man ofta ser dessa partiklar i är batteriteknologi och katalys. De medium som används för att studera omvandlingarna är en lösning som efterliknar ytvatten från en klar sjö. Exponeringar gjordes både med denna lösning så som den är och med tillsatt naturligt organiskt material, NOM.En rad olika experiment gjordes så som analyser med AAS för att undersöka partiklarnas upplösning, NTA för partikelstorlekar och ATR-FTIR som undersökte adsorption på partiklarna. Även en studie med en DCFH metod där ökat ROS aktivitet undersöktes och en rad med SHM simuleringar gjorda i Visual MINTEQ utfördes. Resultaten från NTA och AAS analysen visade sig inte vara särskilt tillförlitliga på grund av tvetydliga resultat som troligen orsakats av problem med provpreparationen. Men resultaten från båda dessa pekar mot att upplösningshastigheten blir något hämmad då man tillsätter naturligt organiskt material, för båda partiklarna. Från ART-FTIR och simuleringarna kunde de säkerhetsställas att adsorption av NOM, karbonat och svavel sker på båda partiklarna, möjligen i fler än ett lager. När det kommer till ROS studien kunde inga bevis på ökad ROS aktivitet hittas med den använda metoden. Dock så kunde inte ökat väteperoxid aktivitet mätas med den metod som användes så detta hade varit av intresse att testa i framtiden. Andra studier som också skulle vara hjälpsamma för att ge en mer nyanserad bild av detta system är en studie om partiklarnas zeta potential och merundersökningar om vilken typ av adsorptions mekanism som sker vid partiklarnas yta.

Gas atomization is a cost-effective processing method to produce fine, spheroidized metal powders. During the process, high velocity jets of gas are sprayed at a molten metal stream to break it into small droplets, which will solidify and form the powder particles. Gas atomized powders usually have a wide size range (1-300 μm), and the range can be up to 500 μm for free-fall gas atomization. Close-coupled gas atomization produces a higher percentage of fine particles and is more attractive to manufacturing applications (-45 μm for MIM, 20-45 μm for SLM, 45-106 μm for EBM). However, compared to the close- coupled process, free-fall type suffers less from the problem that the splashing melt can solidify on gas nozzles. It is believed that by improving the nozzle configuration and arrangement design, the yield and powder particle fineness can be improved. Gas nozzle design is one of the key factors to control gas properties and thus the powder characteristics. Visualization techniques (shadowgraphy and Schlieren imaging) and computational fluid dynamics (CFD) were used to investigate the gas flow from the free- fall atomizer. Schlieren imaging method was used to validate the CFD model, but the results did not match. Potential causes of the discrepancy that affect the CFD model include problems with discretization, input data, boundary conditions and the selection of, and parameters in the turbulence model. A qualitative parametric study was performed using this CFD model to test different designs and study the effect of gas nozzle diameter, angle, distance between melt and gas nozzles. The results showed that a smaller diameter (e.g. decreasing from1.7 mm to 1.0 mm) resulted in the recirculation intensity(maximum pressure) decreasing from  2.4 bar to  1.9  bar and  the  gas  velocity  hitting  axis  of  the  melt nozzle increasing from 301m s-1  to 426 m s-1; a smaller angle (e.g. decreasing from 30º to 10º) resulted in a decrease in both recirculation intensity (from 3.5 bar to 2.4 bar) and gas velocity hitting the axis (from 390m s-1to 301 m s-1); a smaller distance between melt and gas nozzles (e.g. reducing 30mm to 13 mm) resulted in an increase in both recirculation intensity (from 1.9 bar to 2.4 bar) and gas velocity hitting the axis (from 254m s-1to 301 m s-1).  In addition, a smaller diameter or shorter distance made the flow decay earlier. For example, thetransition point between shock units and turbulence occurred 0.301 m downstream of the melt nozzle when the gas nozzle diameter was 1.7 mm, but after 0.182 m when the diameter was reduced to 1.0 mm. It was estimated that a smaller diameter combined with larger angle and distance (e.g. ∅1.7mm, 30º, 30mm in this study) will improve gas flow in gas atomization. It was estimated that a smaller gas nozzle diameter combined with a larger angle and distance between the gas nozzles (e.g. ∅1.7mm, 30º, 30mm in this study) will improve gas flow in gas atomization. This combination brought a less intense recirculation zone and relatively high energy in the gas to break the melt in a relatively long flow region. / Gasatomisering är en kostnadseffektiv metod för att tillverka fint, sfäriskt metallpulver. Processen går till så att gas med väldigt hög hastighet sprayas mot en stråle med smält metall. Metallstrålen bryts upp i små, små droppar som stelnar och bildar pulverpartiklar. Gasatomiserat pulver har normalt en stor storleksfördelning (1-330 μm), och spannet kan gå upp till 500 μm för free-fall gasatomisering. Close-coupled gasatomisering ger en högre andel fina partiklar och är mer intressant för olika applikationer ( -45 μm till MIM, 20 -45 μm till SLM och 45-106 μm för EBM). Jämfört med close-coupled processen har free-fall mindre problem med att smälta skvätter upp och stelnar på gasmunstycket. Det anses vara så att genom att kombinera olika parametrar och optimera munstyckesdesignen så kan utbytet och finheten på pulverpartiklarna förbättras.  Designen på gasmunstycket är en av nyckelfaktorerna för att kontrollera egenskaperna på gasen och därmed egenskaperna på pulvret. Olika tekniker för att visualisera ( Shadograph och Schlieren imaging) användes tillsammans med computational fluid dynamics (CFD) för att undersöka gasflödet från free-fall munstycket. Schlieren imaging användes för att validera CFD-modellen men resultaten matchade inte varandra. Troliga källor till avvikelserna kan vara problem med diskretisering, indata, randvillkor och turbulensmodellen. En kvalitativ parameterstudie gjordes genom att använda CFD –modellen och testa olika design och effekter av gasmunstyckes diameter, vinkel samt avstånd mellan smälta och gasnozzel. Resultatet visade att en mindre diameter (en minskning från 1,7 mm till 1,0 mm) resulterade i att intensiteten på gasen i recirkulationszonen               (maximala trycket) minskade från 2,4 bar till 1,9 bar och att hastigheten på gasen som träffade metallnozzelns axel ökade från 301 m/s till 426 m/s. En mindre vinkel ( en minskning från 30° till 10°) resulterade i en minskning i både intensitet på recirkulationen       ( från 3,5 bar till 2,4 bar) och gashastighet när den träffar axeln  ( från 390 m/s till 301 m/s), ett mindre avstånd mellan smält- och gasmunstycke ( en minskning från 30 mm till 13 mm) resulterade i en ökning i både intensitet på recirkulationen ( från 1,9 bar till 2,4 bar) och gashastigheten när den träffar axeln (från 254 m/s till 301 m/s). Dessutom gav en mindre diameter eller kortare avstånd att flödet avtog tidigare. Till exempel,  omvandlingspunkten mellan shockvågor och turbulens minskades från 0,301 m till 0,182 m när diametern minskades från 1,7 mm till 1,0mm. Utfallet bedöms som att en mindre diameter kombinerat med en större vinkel och längre avstånd (diameter 1,7 mm, 30 grader, 30 mm i denna undersökning) kommer att förbättra gasflödet vid gasatomisering. Jämfört med andra designer så hade denna mindre intensiv recirkulationszon, relativt mycket energi för att bryta upp smältan och ganska långt flödesområde.

Material characterization was addressed by solving the inverse engineering problem to mechanical properties by means of finite element analysis and computational optimization. High-temperature and high strain-rate data from split Hopkinson pressure bar tests on commercially pure titanium were used in the study. The Johnson-Cook flow stress model was selected to characterize the mechanical behavior of the material. By optimizing the model parameters, the force-displacement curve could be reasonably reproduced for the high-temperature bcc phase at strain rates of 1200s−1. A combination of Abaqus finite element simulations and Matlab parameter optimizations has been employed using the program “Abaqus2matlab” for parameter transfer. The approach shows satisfactory results. / Genom att använda s.k “inverse engineering”, med finita elementmetoden och optimeringsrutiner har karaktärisering av mekaniska egenskaper kunnat genomföras. Högtemperaturdata med stor deformationshastighet, erhållna från split-Hopkinson tryckstångstest på kommersiellt ren titan har använts i studien. Johnson-Cook modellen valdes för att modellera de mekaniska egenskaperna hos materialet. Genom att optimera modellparametrarna kunde kraftförskjutningskurvan nöjaktigt reproduceras för högtemperaturfasen bcc, vid töjningshastigheter av 1200 s-1.En kombination av finita elementsimuleringar med Abaqus och parameteroptimeringar med Matlab har genomförts med hjälp av programmet “Abaqus2matlab” för parameteröverföring. Metoden visar på tillfredsställande resultat.

This thesis deals with physiological and mechanical properties of fast and slow twitch mouse muscles. It discusses isometric, concentric and eccentric contractions of mouse extensor digitorum longus ('EDL') and soleus ('SOL') muscles. This project primarily investigated the behaviors of muscles, to give better understanding and improved descriptions for the human system, when subjected to impact or sustained high loading conditions. Muscle force has been shown to be length and activation dependent. The effect of passive or active length changes on muscle force production was studied. Isometric activation showed a maximal force at optimum length for each individual muscle, to which all experiments were related. This optimum length was stimulation frequency dependent and maximum produced force shifted towards shorter length with increasing frequency. Active shortening of maximally stimulated muscle was shown to produce reduced force, but also a reduced isometric force (force depression) following shortening, regardless of the shortening conditions and the method of muscle stimulation. Steady state force depression (ΔFstdep) was correlated with the instant force depression ΔFidep, pre-activation time, t0-t1 and the work (WS), performed by the muscle during shortening. It was positively correlated with the ΔFidep when the shortening magnitude was varied ('VSM'). But in varying the shortening velocity ('VST'), it was negatively correlated with the instant force depression. In active stretch, force was analogously enhanced during stretch, and this effect remained after stretch. Steady state force enhancement (ΔFstenh)following muscle stretch was correlated with the instant force enhancement,ΔFienh, pre-activation time, t0-t1 and the work (WL), done on the muscle during stretch. It was positively correlated with ΔFienh when the stretch magnitude was varied ('VLM'). But in varying the stretch velocity ('VLT'), ΔFstenh was negatively correlated with ΔFienh. Furthermore, the rise time constant, (Tr) of redeveloped isometric forces following the shortening and the fall time constant, (Tf) of the relaxed isometric force following muscle stretch were calculated. In VSM, Tr and Fstdep were positively correlated with each other, while in VST, they were negatively correlated. Tf and Fstenh were negatively correlated in both VLM and VLT. / QC 20101122

<p>QC 20101123</p>

Lead chalcogenides and tin chalcogenides and their alloys are IV−VI family semiconductors with unique material properties compared with similar semiconductors. For instance, PbY (Y = S, Se, and Te) are narrow-gap semiconductors with anomalous negative pressure coefficient and positive temperature coefficient. It is known that this behavior is related with the symmetry of wave functions in first Brillouin zone L-point, which moves the edges of valence band maximum and conduction band minimum towards each other with pressure increasing. SnTe has opposite behavior since its wavefunction symmetry is different from PbY. Therefore, by alloying PbTe and SnTe one can change and control the band gap energy and its pressure or temperature dependence. These chalcogenides alloys have therefore a huge potential in industrial low-wavelength applications and have been attracted the attention of researchers. This thesis comprises theoretical studies of PbY, SnY (Y = S, Se and Te) and the Pb1−xSnxTe alloys (x = 0.00, 0.25, 0.50, 0.75, and 1.00) by means of a first-principles calculation, using the full-potential linearized augmented plane waves method and the local density approximation. The optical properties of Pb1−xSnxTe alloys are investigated in terms of the dielectric function ε(ω) = ε1(ω) + iε2(ω). We find strong optical response in the 0.5–2.0 eV region arising from optical absorption around the LW-line of the Brillouin zone. The calculated linear optical response functions agree well with measured spectra from ellipsometry spectroscopy performed by the Laboratory of Applied Optics, Linköping University. The calculations of the electronic band-edges of the binary PbY and SnY compounds, show similar electronic structure and density-of-states, but there are differences of the symmetry of the band-edge states at and near the Brillouin zone L-point. PbY have a band gap of Eg 0.15−0.30 eV. However, SnY are zero-gap semiconductors Eg = 0 if the spin-orbit interaction is excluded. The reason for this is that the lowest conduction band and the uppermost valence band cross along the LW line. When including in PbY. Although PbY and SnY have different band-edge physics at their respective equilibrium lattice constants, the change of the band-edges with respect to cell volume is qualitatively the same for all six chalcogenides. The calculations show that the symmetry of band edge at the L-point changes when lattice constant varies and this change affects the pressure coefficient. the spin-orbit interaction a gap Eg ≈ 0.2 eV is created, and hence this gap is induced by the spin-orbit interaction. At the L-point, the conduction-band state is a symmetric state and the valence-band state is antisymmetric thereby the L-point pressure coefficient +4L−4LpEg∂∂/)L( in SnY is a positive quantity. In contrast to SnY, the PbY compounds have a band gap both when spin-orbit coupling is excluded and included; this gap is at the L-point, and the conduction-band state has and the valence-band state has symmetry, and thereby this band edge yields the characteristic negative pressure coefficient +4L−4LpEg∂∂/)L( / QC 20101117

Material wear is an ever present phenomenon and can never be completely removed in systems of moving parts. There will always be friction between materials, causing degradation of these materials and eventually the material will be worn out and have to be replaced. In industrial applications, the cost of failure of a material is severe and thus it is important to understand how long a material will operate at a certain working condition. Thus in order to be able to predict the life of a material, the wear mechanisms of the application need to be understood. Squeezing wear or three body wear is a phenomenon occurring when abrasive particles are rolling between two material surfaces. This is not a well researched field, especially when it concerns two steel surfaces with abrasives present between them. Thus the objective of this study was to observe the effect of abrasive particles on the wear of the materials. For this purpose, pin and disk wear tests were conducted both in the presence and absence of abrasive particles. The results show that the abrasive particles act as a buffer between the two materials and hence the specific wear rate observed when the abrasive particles are present is far lesser than the specific wear rate in their absence. Thus this confirms previous research findings that the rate of wear in three body abrasion is lower than the wear rate in two body abrasion. Adhesive wear was observed in one of the material combinations in the absence of abrasive particles. This is a severe type of wear and occurs at far higher rate than observed for two-body or three-body abrasion. / Materialslitage är ett ständigt närvarande fenomen och kan aldrig tas bort helt i system med rörliga delar. Det kommer alltid att finnas friktion mellan material, vilket orsakar nedbrytning av dessa och så småningom kommer materialet att bli utslitet och måste bytas ut. I industriella applikationer är kostnaden för att materialet går sönder stora och det är därför viktigt att förstå hur länge ett material kommer att fungera vid ett visst arbetsförhållande. För att kunna förutsäga livslängden för ett material måste således slitagemekanismerna för applikationen förstås. Klämslitage eller slitage på tre kroppar är ett fenomen som uppstår när slipande partiklar rullar mellan två materialytor. Detta är inte ett välundersökt område, speciellt när det gäller två stålytor med slipmedel närvarande mellan dem. Således var målet med denna studie att observera effekten av slipande partiklar på materialets slitage. För detta ändamål utfördes ”pinne på disk” förslitningstester, både i närvaro och frånvaro, av slipande partiklar. Resultaten visar att de slipande partiklarna fungerar som en buffert mellan de två materialen och följaktligen är den specifika nötningshastigheten som observeras när de slipande partiklarna är närvarande mycket lägre än den specifika nötningshastigheten i deras frånvaro. Detta bekräftar sålunda tidigare forskningsresultat att slitaget vid trekropparsnötning är lägre än vid tvåkropparsnötning. Adhesiv nötning observerades i en av materialkombinationerna i frånvaro av slipande partiklar. Detta är en allvarlig typ av slitage och uppträder i mycket högre takt än observerat för nötning mellan två eller tre kroppar.

The main purpose of this thesis is to see if it is possible to use additive manufacturing(AM) for field repair and maintenance of the assault rifle AK5C, by finding a suitableadditive manufacturing process and make a functional evaluation of the additivemanufactured components: hammer axis, gas cylinder and the magazine follower. TheSwedish Defense Materiel Administration (FMV) is an administration that supplies theSwedish armed forces with materiel. Therefore, it is in their interest to investigate if itis possible to use AM for field repair and maintenance in example Mali or Afghanistan.Based on a survey, and the fact that the components are purelystructural Powder Bed Fusion AM was selected. The hammer axis was made in amargining steel MS1, the gas cylinder in the nickel-alloy called Inconel 718 and themagazine follower was made in a polymer called nylon 12.The functional evaluation of the components took place at Saab in Östersund, whereeach component was placed in the rifle. The rifle was fired 1000 rounds with thehammer axis, 1000 rounds with the gas cylinder and 500 rounds with the magazinefollower. The functional test for the components was successful, there were also nomajor changes in dimensions and weight except for the hammer axis. The diameterfor the hammer axis went from 5,00 mm before the functional test to 4,98 mm afterthe functional test. The microscope images showed thatabrasion had occurred, not only for the hammer axis but also for the magazinefollower, due to friction. Firing speed was also measured and it should be over 600rounds/min, if everything works properly. The hammer axis had a firing speed of 639rounds/min which is good while the gas cylinder only had a firing speed of 595rounds/min. This was because the inner diameter of the cylinder was too big, causinggas leaking and pressure drop inside the gas cylinder.In conclusion, additive manufacturing does allow for fabrication of functional spareparts – at least these evaluated here.

The essay addresses the question "Can a new context for a material change the experience of it?" The materials used in the work are carabiner, tile and industrial net. I go through my perceptions about the materials and try to explain what one could do with them instead in a furniture context. I tell you about my inspiration I have had before and during my work and present how my ideas have evolved during the process. The end result is a clothes rack with the carabiner, a display shelf with the tile and a wall hung shelf with the industry net. Since the question is highly subjective, I have chosen to answer it from my own perspective. The short answer is yes

Now that the EU and Sweden have adopted a new climate policy framework to regulate net carbon emission. A new concept, negative CO2 emission, has been considered to neutralize the CO2 generated from necessary consumption of fossil fuel. Biochar, as a pyrolytic product from biomass, can store carbon in a relatively stable way. Therefore, it is one of the most promising and outstanding tools for carbon sink. Biochar stability, defined as the ratio of remaining carbon in biochar after 100 years, is the most crucial factor when using biochar for carbon storage. So far, various approaches have been proposed to measure and predict biochar stability, such as elemental analysis, proximate analysis, accelerating aging methods. Each method has its pros and cons. The reliability of these methods still needs to be verified. In this project, the chemical accelerating aging method has been selected for assessing biochar stability, because this method captures both chemical and physical properties of biochar. Besides, the gas, liquid, and solid products generalized during the chemical treatment are collected and analyzed separately in order to study the oxidation mechanism. Biochar in this project is produced from miscanthus and seaweed at various pyrolysis temperature. It is found that biochar stability can be increased by enhancing pyrolysis temperature, and miscanthus biochar is more sensitive to pyrolysis temperature within the pyrolysis temperature range of 350-600℃. The highest biochar stability (73%) has been achieved with miscanthus-derived biochar produced at 550 ℃, which demonstrates high potential as carbon sequestration tool. / Nu när EU och Sverige har antagit en ny klimatpolitisk ram för att reglera nettokoldioxidutsläppen. Ett nytt koncept, negativt koldioxidutsläpp, har ansetts neutralisera den koldioxid som genereras av nödvändig förbrukning av fossila bränslen. Biokol, som en pyrolytisk produkt från biomassa, kan lagra kol på ett relativt stabilt sätt. Därför är det en av de mest lovande och enastående verktyg för kolsänka. Biokolsstabilitet, definierad som förhållandet mellan återstående kol i biokol efter 100 år, är den viktigaste faktorn vid användning av biokol för kollagring. Hittills har olika metoder föreslagits för att mäta och förutsäga biokolsstabilitet, såsom elementär analys, proximate analys, accelererande åldrande metoder. Varje metod har sina för-och nackdelar. Tillförlitligheten hos dessa metoder måste fortfarande kontrolleras. I detta projekt har den kemiska accelererande åldrandemetoden valts ut för att bedöma biokolsstabilitet, eftersom denna metod fångar upp både kemiska och fysikaliska egenskaper hos biokol. Förutom, gasen, flytande, och fasta produkter generaliserade under den kemiska behandlingen samlas in och analyseras separat för att studera oxidation mekanism. Biokol i detta projekt framställs av miscanthus och tång vid olika pyrolystemperatur. Det visar sig att biokolsstabiliteten kan ökas genom att öka pyrolystemperaturen, och miscanthusbiokol är mer känsligt för pyrolystemperatur inom pyrolystemperaturområdet 350-600°C. Den högsta biokolsstabiliteten (73%) har uppnåtts medbiokol som framställts vid 550°C och som visar stor potential som kolbindningsverktyg.