Fuel cells are more efficient and cleaner than combustion engines. Ethanol as a fuel has a high energy density and is safer and easier to handle than hydrogen which is normally used in fuel cells. If efficient fuel cells on alcohol were available, they could be used for engines and power sources for electronics. Platinum-tin surfaces have proven to be good catalysts for ethanol and an improvement over pure platinum. The mechanism and the structure during catalysis are not well known. An experiment was performed at the Hippie beam line at Max IV to improve the knowledge in this area. The (111) surface of Pt and Pt3Sn alloy and the (223) surface of Pt, was exposed to ethanol and oxygen. Pt and Pt3Sn both have face-centered-cubic (FCC) crystal structures. The (111) surface is the most close-packed in an FCC crystal. A (223) surface is a (111) surface cut at a low angle. So it has the appearance of a stepped (111) surface. The edges on the (223) surface should increase the activity compared to the (111) surface. The surfaces and the gas phases were measured in situ with ambient pressure x-ray photoelectron spectroscopy and a quadrupole mass spectrometer was used to analyze the gas composition. The hypothesis that increasing the number of edges as with the Pt(223) surface should increase the activity is accurate. Pt(223) was more active than Pt(111). Pt(223) and Pt3Sn(111) have similar ethanol conversion rate. Increasing the oxygen-to-ethanol ratio increased the activity both with Pt(111) and Pt(223), Pt3Sn(111) was not tested with increased oxygen-to-ethanol ratio. The gas phases were analyzed, and the existing compounds were identified. Acetaldehyde shows up in the C1s gas spectrum in all of the sequences. When ethanol decreases acetaldehyde increase. The difference between these two compounds is only two hydrogen atoms. This reaction is the start of the catalytic process and it is the same for all tested crystals. Ethylene (CH2CH2) shows up as a vague peak in the gas phase. It is only present at higher temperatures and with a low oxygen rate. Compared to the other crystals the Pt3Sn(111) sample doesn't produce CO2, at least not to a detectable degree. In the gas phases of the other crystals, the CO2 peak was visible. Pt(223) creates CO2 but to a lesser degree than Pt(111). The goal of the experiment was to investigate which Sn phases are present during ethanol oxidation. This turned out to be difficult. The Pt3Sn crystal was carbon poisoned during the first test sequence and the graphite layer was not possible to remove during the beam time. Curve fitting of the Sn3d peak resulted in two components. The components were Pt3Sn alloy and Sn with adsorbed molecules. The expected SnO2 and SnO peaks notably absent. The oxygen probably bonds with carbon instead of tin. Carbon was present on the surface due to insufficient cleaning. In the oxygen spectrum, chemically bonded oxygen seems to be present from 100 °C, as SnO2 or SnO. This peak is most likely from some other component containing oxygen. If oxygen is bonded to Sn, it should be visible in the Sn3d peak, unless it is hiding underneath one of the present peaks. According to Batzill et al. a quasimetalic state consisting of oxidized Sn alloyed with Pt has a similar binding energy as Pt3Sn alloy. So it could be that the oxygen is hiding underneath the Pt3Sn alloy component. The experiment has improved the knowledge of ethanol oxidation on platinum and platinum-tin surfaces. The knowledge gained here is a good start for further experiments and simulations.

Titanium and its alloys are widely used in applications ranging from aeroengines and offshore equipment to biomedical implants and sporting goods, owing to their high ratio of strength to density, excellent corrosion resistance, and biomedical compatibility. Among the titanium alloys used in aerospace, Ti-6Al-4V (an α+β alloy) is the most widely used, in applications in which the temperature may reach 350°C, at which point it retains good fatigue and fracture properties as well as moderate tensile strength and ductility. These alloy properties are dependent on variables such as crystalline structure, alloy chemistry, manufacturing techniques and environmental conditions during service. These variables influence the microstructure and mechanical properties of titanium alloys. With regard to the alloy chemistry and operating environment, the focus of the present work is to understand the influence of boron and hydrogen on the microstructure and selected mechanical properties of cast Ti-6Al-4V. The addition of boron to cast Ti-6Al-4V (0.06 and 0.11 wt% in this work) refines the coarse “as cast” microstructure, which is evaluated quantitatively using FoveaPro image analysis software. Compression testing was performed using a Gleeble 1500 instrument, by applying a 10% strain at different strain rates (0.001, 0.1 and 1 s-1) for temperatures in the range 25-1100°C. The tests were performed to evaluate the effect of boron on the mechanical properties of the alloy. It was observed that there is an increase in the compressive strength, predominantly at room temperature, of cast Ti-6Al-4V after the addition of boron. Metallographic evaluation showed that this increase in strength is a likely result of reductions in both the prior β grain and α colony dimensions, which is caused by boron addition. Studies in a hydrogen environment at 150 bar showed that cast Ti-6Al-4V exhibited lower yield strength and lower ultimate tensile strength in comparison with those properties measured in an air environment. No significant change in the ductility was observed. It was also noted that in a high strain range (≈2%) the low cycle fatigue (LCF) life was significantly reduced in hydrogen compared with air. Microstructural and fractographic characterization techniques were used to establish the role of hydrogen on the deformation mechanism by analysing the crack propagation path through the microstructure. It is seen that cracks tend to propagate along the interface between prior β grain boundaries and/or along the α colony boundaries

The martensite structure is the most important microstructure in tool steel due to its high hardness. However, a lack of ductility is the major drawback. In order to improve the ductility and still maintaining a suitable hardness a tempering process is needed. The tempering process will cause recovery and recrystallization in the matrix, and moreover carbides will precipitate. The specific carbides have different characteristics and thus the type of carbide formed during tempering is very important for the properties of the steel. The simulation software (TC-Prisma) is interesting because it can predict type, size, and amount of carbides. The present study was carried out to investigate both the microstructure, hardness evolution of martensite and precipitation which occurred in Fe-C-Cr steel with different compositions, tempered at 700oC. The experimental results were compared with simulation results. Micro-Vickers hardness test with a load of 100 g was used and the hardness value dropped 40% and 60% in low carbon alloy and high carbon alloy steels, respectively. The significant drop occurred during the first 30 seconds of tempering due to recovery of the matrix. Hardness values slightly decreased and then stabilized during continued tempering. The microstructure of martensite and the morphology of carbides at different tempering times were examined by scanning and transmission electron microscopy in order to study the precipitation of carbides from the nucleation and growth to coarsening. There are three types of carbides which precipitated in the Fe-C-Cr specimens: M7C3, cementite and M3C2 depending on the composition. Fe-0.16C-4.05Cr contained M7C3, Fe-0.95C-1.065Cr contained cementite and M3C2 and Fe-014C-0.983Cr and Fe-0.88C-4.12Cr contained M7C3 and cementite. M7C3 has a faceted shape and precipitates referentially at grain boundaries. On the other hand, cementite has an elongated shape and precipitated mainly at grain boundaries but also intragranulary. M3C2 has a rounded shape and was seen only in very small amounts, and seemed to precipitate at random sites. The trend of carbide growth in experiments is consistent with the simulations using TC-Prisma, but more work is needed to enable quantitative comparisons.

Sandvik Coromant in Gimo is in need of a good quality evaluation method of adhesion for PVD layers; since the existing testing method is located in Sandvik Coromant’s other location in Västberga. Different micro-blasting methods were investigated in this thesis and the results show that some of the methods could potentially be used for evaluation of adhesion, more specifically the wet blasting methods, M1 and M2. The results also show that the investigated geometry received varying adhesion quality when lower etching bias in the PVD process was used and when different sides was pointing upwards in the PVD furnace. Further investigation will have to be made in order to fully implement micro-blasting as a testing method in production.

High entropy alloys (HEAs) are a new class of alloys that contains five or more principal elements in equiatomic or near-equiatomic proportional ratio. The configuration entropy in the HEAs tends to stabilize the solid solution formation, such as body-centered-cubic (BCC), face-centered-cubic (FCC) and/or hexagonal-closed-pack (HCP) solid solution. The high number of principal elements present in HEAs results in severe lattice distortion, which in return gives superior mechanical properties compared to the conventional alloys. HEAs are considered as a paradigm shift for the next generation high temperature alloys in extreme environments, such as aerospace, cutting tools, and bearings applications. The project is based on the development of refractory high entropy alloy and film. The first part of the project involves designing high entropy alloy of CuMoTaWV using spark plasma sintering (SPS) at 1400 oC. The sintered alloy showed the formation of a composite of BCC solid solution (HEA) and V rich zones with a microhardness of 600 HV and 900 HV, respectively. High temperature ball-on-disc tribological studies were carried out from room temperature (RT) to 600 oC against Si3N4 counter ball. Sliding wear characterization of the high entropy alloy composite showed increasing coefficient of friction (COF) of 0.45-0.67 from RT to 400 oC and then it decreased to 0.54 at 600 oC. The wear rates were found to be low at RT (4 × 10⁠−3 mm⁠3/Nm) and 400 oC (5 × 10⁠−3 mm⁠3/Nm) and slightly high at 200 oC (2.3 × 10⁠−2 mm⁠3/Nm) and 600 oC (4.5 × 10⁠−2 mm⁠3/Nm). The tribology tests showed adaptive behavior with lower wear rate and COF at 400 oC and 600 oC, respectively. The adaptive wear behavior at 400 oC was due to the formation of CuO that protected against wear, and at 600 oC, the V-rich zones converted to elongated magneli phases of V2O5 and helped in reducing the friction coefficient. The second part of the project consists of sintering of novel CuMoTaWV target material using SPS and depositing CuMoTaWV refractory high entropy films (RHEF) using DC-magnetron sputtering on silicon and 304 stainless steel substrate. The deposited films showed the formation of nanocrystalline BCC solid solution. The X-ray diffraction (XRD) studies showed a strong (110) preferred orientation with a lattice constant and grain size of 3.18 Å and 18 nm, respectively. The lattice parameter were found to be in good agreement with the one from the DFT optimized SQS (3.16 Å). The nanoindentation hardness measurement at 3 mN load revealed an average hardness of 19 ± 2.3 GPa and an average Young’s modulus of 259.3 ± 19.2 GPa. The Rutherford backscattered (RBS) measurement showed a gradient composition in the cross-section of the film with W, Ta and Mo rich at the surface, while V and Cu were found to be rich at the substrate-film interface. AFM measurements showed an average surface roughness (Sa) of 3 nm. Nano-pillars of 440 nm diameter from CuMoTaWV RHEFs were prepared by ion-milling in a focused-ion-beam (FIB) instrument, followed by its compression. The compressional yield strength and Young’s modulus was calculated to be 10.7 ± 0.8 GPa and 196 ± 10 GPa, respectively. Room temperature ball-on-disc tribological test on the CuMoTaWV RHEF, after annealing at 300 oC, against E52100 alloy steel (Grade 25, 700-880 HV) showed a steady state COF of 0.25 and a low average wear rate of 6.4 x 10-6 mm3/Nm.

NOx (NO, NO2) is one of the most harmful air-pollutants from exhaust, resulting in series of environmental problems as well as severe healthy issues for human beings. Selective catalytic reduction (SCR) system is a common approach to eliminate NOx onboard by using ammonia as a reductant. However, ammonia storage unit has been one of the restriction factors for the NOx conversion efficiency because of insufficient ammonia dosing rate and the corrosive and hazardous nature of ammonia. Thus, a reliable ammonia storage and delivery system is of high scientific and commercial desire. In this thesis, novel composites were fabricated and studied based on MgCl2 and SrCl2, two commercial alkaline earth metal halides (AEMH) for ammonia storage. In order to reduce the melting issue and enhance the kinetics of the ammonia sorption, carbon materials, graphite (Gt) and graphene nanoplatelets aggregates (GNA) were added to MgCl2 at 1 wt.%, 10 wt.% and 20 wt.%. With ball milling and hydraulic pressing, the aforementioned carbon-MgCl2 composites were structured into pellets for various characterization. With real-time recording in the tube furnace at 1073 K, we observed that with 20% carbon additives, the pelletized composites maintained their structure with 95% mass retention, while the pure MgCl2 completely melted and disintegrated. According to the SEM images, carbon materials separated MgCl2 so that the molten MgCl2 cannot form large droplet to spread out. Furthermore, the 20 wt.% GNA-80 wt.% MgCl2 (GNA20) composites demonstrated enhanced kinetics in both absorption and desorption of ammonia, which is 83% faster in ammonia absorption and 73% faster in desorption in the first two minutes compared to the pure MgCl2. The BET surface area and mercury intrusion porosimetry results explains the kinetic elevation by the GNA by introducing extra reaction surface and nanopores as the diffusion path for ammonia. The enhancement of both structural stabilityand kinetics make the GNA20 composite a robust ammonia carrier. During the chemical absorption process, SrCl2 uptakes 8 ammonia molecules resulting in 4 times volume expansion. This dramatic expansion and shrinkage during the absorption and desorption will destroy the structure and disintegrate the SrCl2 into powder, which could bring the dust explosion risk for many applications. Based on the carbon-salts composites, a novel porous SrCl2 structure is designed and fabricated with graphene oxide as skeleton by freeze casting process. Porous SrCl2 structure is feasible for various geometries with different molds at a wide SrCl2 load from 0 wt.% to 96 wt.%. The ammonia capacity of the porous SrCl2 is linear proportional to the SrCl2 load. During the ammonia absorption and desorption cycles, the graphene oxide skeleton could self-adjust along with the volume swing to within its flexibility. This porous SrCl2 demonstrates excellent tolerance of volume swing and enhanced kinetics as a promising ammonia storage material. Our approach and results may cast light on the obstacles of structuring self-expansion and shrinkage materials as well as on enhancing the gas sorption properties.

Concrete in its unaltered form allows the mass transfer of fluids into and out of its microstructure. These fluids can contain detrimental solutes which change the chemistry of the cement paste and/or the corrosion properties of the reinforcement bars, most noticeably hydrogen carbonates (HCO3-), oxygen (O2) and chloride ions (Cl-). Water and its solutions containing salts, mostly sodium chloride (NaCl), can also cause physical damage due to phase changes (freezing and thawing).  External application of hydrophobic agents onto the cement paste surface is a well-known method to alter the mass transfer at this interface. Bulk application of hydrophobic agents in ready mixed concrete is also a possible route but alters the entire cement paste. This thesis presents relevant aspects concerning the use of bulk hydrophobic agents in concrete within a spectrum water to cement ratio   (w/c) = 0.40-0.50. The main focus was on triacylglycerides (TAG) and alkyl alkoxysilanes (“silanes”) with application rates 1-3% based on cement weight.  Alterations to the compressive strengths have been observed and documented over a three-year period. The relative drop in mechanical strength is inversely proportional to w/c. The higher the addition rate, the lower the compressive strength. Chemical differences within the hydrophobic groupings (TAG or “silanes”) resulted in different outcomes. This was most noticeable in the water absorption, compressive strengths and chloride diffusion.  Freeze thaw testing did show noticeable differences, the use of “silanes” was detrimental in these tests even in deionsed water. The exact mechanism is unknown, but thin section analysis shows a lack of air entrainer (even when added on the fresh concrete mix) and extensive cracking in the entire cement paste. The scaling in concrete with TAGs was smaller but needs further improving.  The main properties intended with these agents were the ability to alter the mass transfer of water or solutions into the cement paste. Capillary suction and diffusion were examined. Increasing the w/c reduces the effectiveness of the hydrophobic agents to resist water uptake. This was seen in capillary suction and uni-directional chloride diffusion testing. Processed TAGs were more effective in reducing chloride diffusion than the unprocessed chemical whereas, in some cases, the “silanes” actually increased the amount of chloride ions transferred into the cement paste. Only a slight positive effect can be seen at the lower inclusion rate (1%). Increasing the w/c reduces the resistance to chloride ion diffusion with the same dosage rate.  A field test station close to vehicular traffic was also established in 2018 and 2019, but the specimens have not been tested at this point in time. It is hoped that these and other future studies will lead to a complete PhD project. / Betong i sin oförändrade form tillåter masstransport av vätskor i och ur dess mikrostruktur. Dessa vätskor kan innehålla skadliga lösta ämnen som förändrar cementpastans kemi och/eller korrosionsegenskaperna hos armeringsjärnen, framför allt vätekarbonater (HCO3-), syre (O2) och kloridjoner (Cl-). Vatten och dess lösningar som innehåller salter, mestadels natriumklorider (NaCl), kan till och med orsaka fysisk skada på grund av fasförändringar (frysning och upptining). Extern applicering av hydrofoba medel på cementpastans yta är en välkänd metod för att ändra masstransport genom denna gränsyta. Bulkapplicering av hydrofoba medel i färdigblandad betong är också en möjlig väg, och resulterar i förändringar i hela cementpastan. Denna licentiatavhandling presenterar relevanta aspekter rörande användningen av bulk-hydrofoba medel i betong inom intervall av vattencementtal = 0,40-0,50 (vct). Huvudfokus låg på triacylglyceroler (TAG) och alkyl-alkoxisilaner (”silaner”) med inblandning 1-3 % baserat på cementvikt. Förändringar av tryckhållfasthet har observerats och dokumenterats under en treårsperiod. Den relativa reduktionen i mekanisk hållfasthet är omvänt proportionell mot vct. Ju högre tillsatsmängd i cementpastan desto lägre tryckhållfasthet. Kemiska skillnader inom de hydrofoba grupperna (TAG eller "silaner") resulterade i olika resultat. Detta var mest märkbart i vattenabsorption, tryckhållfasthet och kloriddiffusion. Frysprovning visade märkbara skillnader, användningen av "silaner" var skadlig i dessa tester även i avjoniserat vatten. Den exakta mekanismen är okänd, men tunnslipsanalys visar på brist på luftporbildare (även om den tillsätts i stora mängder i den färska betongblandningen) och omfattande sprickbildning i hela cementpastan. Avskalningen i betong med TAG var mindre men behöver ytterligare förbättras. De huvudsakliga egenskaperna avsedda med dessa medel var förmågan att förändra masstransport av vatten eller lösningar till cementpastan. Kapillärsugning och diffusion undersöktes. Att öka vct minskar effektiviteten hos de hydrofoba medlen för att motstå vattenupptagning. Detta sågs vid kapillärsugning och enkelriktad kloriddiffusionsprovning. Raffinerade TAG:er var effektivare att minska kloriddiffusion än den oraffinerade, medan "silanerna" i visa fall faktiskt ökade mängden kloridjoner som överfördes inne i cementpastan. Något positiva effekt kan ses vid den lägre inkluderingstillsatsen (1 %). Att öka vct minskar motståndet mot kloridjondiffusion. En fältteststation intill fordonstrafik etablerades också 2018 och 2019 men provkropparna har inte testats vid denna tidpunkt. Förhoppningen är att dessa och andra framtida studier ska leda till ett komplett doktorandprojekt. / <p>QC 230330</p>

Historically, table tennis blades have been subject to few changes. Apart from the introduction of a few new materials, such as carbon fibre, resulting from rule changes in the sport, the pace of change has been slow. This project is based on three cases containing potential rule changes to the regulations of the sport regarding the construction of blades. Furthermore, the sport, its user’s needs, and potential new materials to implement have been investigated, resulting in the development of a series of prototypes. A total of 21 prototypes have been used with the aim of improving the control properties of the blade, which along with speed and spin are considered the most important playing characteristics in a table tennis stroke. The overall result from user tests indicates that three of the prototypes possess interesting properties which should be investigated further, out of which two are presented in this report. These prototypes consist of a prototype where a layer of the fibrous material Vectran is included, and a prototype where a layer consists of a honeycomb structure made of the material Nomex, and a third prototype that upon request from the company has been decided to be excluded from the report. Finally, recommendations for further development of these prototypes are described. / Stommar för bordtennisracketar är en produktkategori som historiskt sett genomgått små förändringar. Bortsett från att ett antal nya material, såsom kolfiber, introducerats till följd av olika regeländringar har förändringstakten varit långsam. Detta projekt har utgått från tre projektcase innehållande potentiella regelförändringar av bordtennisens regelverk avseende bordtennisstommens tillåtna konstruktion. Här har sporten, dess användarbehov samt potentiella nya material undersökts vilka prototyper tillverkats utefter. Sammanlagt har 21 prototyper tagits fram vilka främst avser förbättra racketstommens kontrollegenskaper, vilket tillsammans med fart och skruv anses vara de viktigaste spelegenskaperna hos racketen i slagmomentet. Det sammantagna resultatet från användartesterna visar att ett antal av prototyperna besitter intressanta spelegenskaper. Av dessa har tre valts ut vilka rekommenderas att undersökas vidare, varav två presenteras i denna rapport. Detta handlar om en stomme där ett lager av fibermaterialet Vectran används, en stomme där ett lager utgörs av en honeycombstruktur av Nomex, samt en tredje stomme som på företagets önskemål beslutats att ej inkluderas i rapporten. Till sist beskrivs rekommendationer för vidare arbete med dessa koncept.

Materialvalen i byggnader är en av de faktorer som påverkar Sverigesenergianvändning inom byggsektorn. Med god kunskap om materialsegenskaper, underhåll och livslängd kan mer hållbara materialval görasvilket sparar på ekonomin och indirekt miljön.Golv- och fasadmaterials olika egenskaper, underhållsintervall ochkostnader sammanställs och beräknas för att ge en inblick i hur valet avmaterial direkt påverkar användandet av materialresurser. Även hurprivatpersoners total- och underhållskostnad för dessa ytskikt kan varieraberoende på vilket material och ytbehandling som väljs.

This report reviews the different types of medical waste and associated medical waste generation data by geographic regions. Incineration methods and non-incineration methods, together with their associated technologies, are reviewed in detail. Among all the methods, pyrolysis technologies are, in principle, technically and politically attractive due to less pollution and toxic products emissions as compared to other methods (especially traditional incineration methods). In this report, the data are organized and analyzed from a series of pyrolysis tests carried out by KTH according to a technology concept developed by Bioincendia AB.   A combustion system for the pyro gas treatment is built based on the small-scale induction pyrolysis machine. The concept of the pyro gas combustion system is expressed through the block diagram and the boundary conditions are estimated according to the test data and the literature. The result of theoretical calculation indicates the boundary conditions of system are in reasonable range. The critical parameters of heat exchange unit increase the building of whole system.