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Since the investigation of wear particles in rail transport started in late-1910s, the high mass concentration of these particles has raised worries among researchers concerned with air quality. However, effective action has yet to be taken because of lack of relevant knowledge. This thesis provides applicable information for the airborne wear particles in rail transport. Some aspects of their characteristics such as diameter size, mass concentration, number concentration, and morphology of particles were investigated in field tests and laboratory tests.The effects on particle characterisations from different operational conditions in the field tests, and applying different braking materials, conducting tests in different applied loads or sliding velocities in the laboratory tests were studied. The main advantage of conducting laboratory tests was to focus on studying particles from one source. The possibility of repetition, using high sensitive instruments and conducting tests at low costs are the other advantages of laboratory studies. Paper A describes how a pin-on-disc machine was used to reproduce similar real operational conditions during mechanical braking in a train. The results were validated by comparing the field tests results with the laboratory studies. The particles morphology and size distribution were also studied.Paper B presents a summary of field tests results. The effects of curve negotiating and applying braking in different real conditions were investigated with an on-board measurement.The element composition of the particles and their potential sources were also investigated outside of the particles morphologies.Paper C presents comprehensive results from laboratory studies on airborne particles from different braking materials. The differences in the particle characteristics in similar test conditions were attributable to different material compositions and dominant wear mechanisms. A new index was introduced in this paper and is suggested to be used as a qualitative factor with regard to the airborne wear particle emission rate.Paper D is a review of the recent studies of exhaust emission and non-exhaust emission from rail vehicles. A summary of results, measurements, adverse health effects, and proposed or applied solutions are reviewed in this paper. / <p>QC 20110812</p> / JVG F6521

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The oxide scale created during manufacturing of stainless steel is often removed by a chemical pickling with mixed acid. Various pre-treatments to pickling are also applied to increase the efficiency of the oxide scale removal. Shot blasting is one such pre-treatment, which operates to remove a certain amount of oxide and also to generate cracks and openings for the subsequent pickling. In this work, three materials, AISI 2205, 430 and 304 have been blasted and later exposed to mixed acid. This was conducted to quantify the effect shot blasting has on the subsequent pickling of stainless steel. Three shot products and two blasting parameters were investigated and varied. Shot blasting significantly reduced the oxide scale but was unable to remove the chromium oxide layer closest to the steel surface. No significant difference was observed when comparing the result from the three shot products after blasting. Increasing the particle velocity or the coverage rate further enhanced the pickling but reduced the amount of oxide removed during blasting. These effects are however relative small, so in practise relatively mild conditions seems preferable for economic reasons. Oxide scale containing hematite was difficult to remove by both shot blasting and pickling.

Due to growing demands for steel powder properties and continuous evolution of the powder metallurgy (PM) production it is necessary to apply new investigation technics and research applications for quality investigation of the PM products. In addition, it is important to be able to predict the probable maximum size of inclusions. The industrial scale sampling of steel was made in Höganäs AB. The three dimensional (3D) analysis of non-metallic inclusions obtained by electrolytic extraction (EE) method was applied for metal samples taken from liquid steel before water-atomization and after powder forging process. It was demonstrated that the application of the 3D analysis has a perspective and possibility to be used independently or like a reference during 2D analysis of inclusions in powder metallurgy products. The tundish samples have the maximum total number of inclusions but have smaller size of complex inclusion. The size range of inclusions in the ladle and tundish samples is between 1 and 46 μm. The main type of inclusions is spherical (Si-Ca-Al-Mg-O in composition). The powder forged samples have two main types of non-metallic particles: “gray” carbon saturated (10-250 μm) and “bright” clustered oxide particles (1-37 μm with Cr-Si-Mn-Mg-Al-O in composition). The probable maximum size of inclusions was estimated based on a new particle size distribution (PSD) and the standard extreme value distribution (EVD) methods. Both methods predicted that in 1 kg of metal the maximum size of spherical inclusions is &lt; 15 μm in liquid steel samples and the maximum length of “bright” clustered oxide particles is &lt; 63 μm in powder forged samples. However, the prediction of the maximum size by PSD method showed necessity of the further optimization.

Case hardening distortions are a major problem for gear manufacturers. The aim of the current work is to create a simulation model, able to predict how and when case hardening distortions arise. The results presented in this thesis form a basis for such a model. Two case hardening steels, with base carbon contents of 0.20 and 0.21 % C were studied using dilatometer experiments. One of them was carburized to 0.36, 0.52 and 0.65 % C in order to investigate the influence of carbon content. Experiments were performed during both isothermal and continuous heating and cooling conditions. The results were used to evaluate phase transformations, heat expansion behaviors and phase transformation strains. The expansion behavior of the material was modeled as a function of temperature, carbon content and phase fractions. The phase transformations to martensite and bainite were modeled, using the Koistinen-Marburger equation and a transformation rate equation based on Austin-Rickett kinetics, respectively. Experiments were simulated using the COMSOL Multiphysics software, to verify the model with respect to martensite and bainite transformations, heat expansion behavior and phase transformation strains.

Metal-organic frameworks (MOFs) constructed from metal atoms connected by organic linkers have received extensive attention for greenhouse gas separation in the past decades. Moreover, their large surface area makes them a promising candidate as adsorbents for gas sorption. This project aims to develop MOFs via different synthesis instructions by utilizing  Mg-containing materials, including Commercial MgCO3  and Mesoporous Magnesium Carbonate (Upsalite) as a source of the metal part and four different organic linkers. Water, Ethanol, Methanol, and N, N-dimethylformamide were used as solvents. First, synthesis was performed at room temperature, followed by high temperature using an autoclave and reactor. Then, the successfully synthesized samples were characterized by different characterization methods. These characterization techniques included Powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), and Infrared Spectroscopy (IR).  Porous properties of the MOFs were tested by gas adsorption techniques, including N2  and CO2 as adsorbate gases. As a result, it was found that synthesized MOFs have a high surface area and porosity to adsorb greenhouse gases and separate CO2 from N2. The highest surface area, N2, and CO2 adsorption amounts were 539 m²/g, 0.32 (mmol/g at 293K,1bar), and 3.31 (mmol/g  at 293K,1bar), respectively. CO2  adsorption is approximately ten times N2  adsorption in almost all MOF synthesized samples. To achieve the best result regarding the high amounts of surface area, N2, and CO2  sorption,  synthesis at room temperature using Commercial MgCO3, H2dhbq linker, and water solvent was the best approach.

In this project a novel chitosan-stearic acid (CS-SA) coating with bee-pollen microcapsules for encapsulation of 2-mecraptobenzothiazole (MBT) as a waterborne formulation for a biocompatible corrosion protection coating was developed and the coating properties was analyzed. Hydrophobic stearic acid (SA) was crosslinked with via a carbodiimide reaction to form micelles and is assembled on the bee- pollen grains and the chitosan matrix was further self-crosslinked using glutaraldehyde (GA). Stearic acid was used to hydrophobically interact with modified pollen and with further crosslinking with the chitosan, which was proven successful by FTIR results. The encapsulation of anticorrosive agent MBT into pollen was successful and examined by UV-Vis spectroscopy, however, the pollen cannot form a fully stable formulation with the chitosan micelle matrix, partially due to its relatively big size (ca. 20 μm), causing problems with forming a proper barrier protection. The size of the grains and the interference of the carbodiimide crosslinking is the most severe problems with the pollen microcapsules. Therefore, no further testing of the corrosive properties could be done, which requires a dense and stable coating to sustain in salty water for the whole measurement period. As the reference coatings without pollen provided much more promising results, especially when crosslinked with GA, the conclusion is that the reactivity of the pollen is proven difficult to crosslink, and choosing a proper size of a microcontainer and the appropriate encapsulation method in the binder matrix is vital and important for developing a corrosion protective coating. / Detta projekt bygger på framställningen och analysen av en tidigare outforskad chitosan-stearinsyra (CS-SA) färg med bi pollen som mikrokapslar för inkapsling av 2-mercaptobenzothiazole (MBT) som en vattenlöslig och biokompatibel anti-korrosions färg. CS-SA var tillverkat med en carbodiimide reaktion för att bilda miceller som ska omslutna pollenkornen, och även ett försök med vidare tvärbindning mellan chitosanen med glutaraldehyde (GA) gjordes. Stearinsyra fick interagera hydrofobiskt med den modifierade pollen och tvärbindes sedan med chitosan, som visade sig vara lyckad med hjälp av FTIR analys. Enkapsuleringen av MBT visade sig med UV-Vis spektroskopi vara lyckad, dock på grund av pollens stora korn (ca 20 μm) orsakade problem med att bilda en stabil barriär mot omgivningen. Storleken av pollen och dess reaktivitet med carbodiimide tvärbindningen är de mest allvarliga problemen med pollen som mikrokapslar, och därav gjordes inga vidare tester av korrosions egenskaperna då detta kräver en täckande och stabil film genom hela mätningen. Då även referensfärgen som gjordes utan pollen gav avsevärt mycket bättre resultat i det avseendet är slutsatsen att reaktiviteten av pollen gör det problematiskt att tvärbinda med chitosan och valet av en kapsel av rätt storlek och hur den inkapslar är avgörande för att utveckla en bra korrosionsskyddande färg.

Corrosion is a mechanism that highly reduces the lifetime of metals in different environments, especially in water or moisture environment. The worldwide maintenance cost due to corrosion is estimated in billions of dollars per year, and actual solutions in terms of coating usually contains toxic or environmentally harmful species. With an always increasing restriction by environmental restraints and regulations, a sustainable solution is urgently needed. Chitosan, easily obtained from chitin, the second most abundant biopolymer on earth, can be the solution to many problems. Crustacean shell waste is one of the major sources of chitin. Its resource efficiency, biocompatibility, and versatile physicochemical properties for chelation and crosslinking make chitosan a promising candidate as matrix material for biobased anticorrosive application. The purpose of the Master Thesis is to combine the properties of chitosan with the high porosity of bee pollen as anticorrosive agent carrier to obtain a fully sustainable solution for anticorrosive protection. The objective of this very ambitious project is to produce a composite material with a triple action: anticorrosive protection of metal surfaces, self-healing property of the coating and anti- biofouling activity. Results show that a biopolymer composite in forms of suspension or coatings with all desired components could be achieve. Specifically, a biopolymer nanocomposite composed of chitosan matrix, embedded with pollen grains that were loaded with anticorrosion agent 2- mercatobenzothiazole (MBT) in advance, and with zinc oxide nanoparticles have been produced. The physicochemical characterization of the biopolymer composite and its coatings, as well as electrochemical impedance spectroscopy (EIS) measurements on stainless steel plate with such coatings, suggest that a uniform and compact coating is obtained. Despite its good hydrophobicity with maximum contact angle 134.32 ± 3.84° with top coating, the chitosan nanocomposite coating is still permeable to water, partially because of the relatively big size of pollen (ca. 20 μm) that introduces gaps and interferes integrity of the coating. Therefore, a full immersion corrosion resistance is not achieved. In conclusion, phase transfer of hydrophobic pollen into hydrophilic chitosan matrix, MBT loading in pollen, ZnO encapsulation in chitosan, as well as crosslinking of chitosan, were successfully carried out. A coating based on such biopolymer nanocomposite is prepared on stainless steel and investigated on its anti-corrosion property. Future work will be choosing a proper sized pollen as a microcontainer to enhance the integrity of the coating, and eventually endow the coating with the three-in-one function, i.e., anticorrosion, antimicrobial, and self-healing. / Korrosion är en mekanism som kraftigt reducerar livslängden för metaller i olika miljöer, särskilt i vatten- eller fuktmiljö. De globala underhållskostnaderna på grund av korrosion uppskattas i miljarder dollar per år, och faktiska lösningar med avseende på beläggning innehåller vanligtvis giftiga eller miljöfarliga arter. Med en ständigt ökande begränsning genom miljörestriktioner och bestämmelser krävs det en hållbar lösning. Kitosan, den näst vanligaste biopolymeren, kan vara lösningen på många problem. Skaldjuravfall är en av de viktigaste källorna till kitosan. Dess resurseffektivitet, biokompatibilitet och mångsidiga fysikalisk-kemiska egenskaper för kelering och tvärbindning gör kitosan till en lovande kandidat som matrismaterial för biobaserade antikorrosiva applikationer. Syftet med denna masteruppsats är att kombinera egenskaperna hos kitosan med den höga porositeten hos bipollen som antikorrosivt medel för att erhålla en helt hållbar lösning för korrosionsskydd. Målet med detta mycket ambitiösa projekt är att producera ett sammansatt material med en tredubbel verkan: korrosionsskydd för metallytor, självhelande egenskap hos beläggningen och anti- biobeväxningsaktivitet. Resultaten visar att en biopolymerkomposit i form av suspension eller beläggningar med alla önskade komponenter kan uppnås. Specifikt har en biopolymer-nanokomposit sammansatt av kitosanmatris med inbäddade pollenkorn, som i förväg packats med antikorrosionsmedlet 2-mercaptobenzotiazol (MBT) och med zinkoxid-nanopartiklar, producerats. Den fysikalisk-kemiska karakteriseringen av biopolymerkompositen och dess beläggningar, liksom elektrokemiska impedansspektroskopimätningar (EIS) på rostfri stålplåt med sådana beläggningar tyder på att en enhetlig och kompakt beläggning erhålls. Trots sin goda hydrofobi med maximal kontaktvinkel 134,32 ± 3,84° med toppbeläggningen, är nanokompositbeläggningen av kitosan fortfarande permeabel för vatten, delvis på grund av den relativt stora storleken hos pollen (ca. 20 μm) som introducerar luckor och stör integriteten hos beläggningen. Därför uppnås inte en fullständig immersionskorrosionsbeständighet. Sammanfattningsvis genomfördes fasövergång av hydrofobt pollen till hydrofil kitosanmatris, MBT-packning i pollen, ZnO-inkapsling i kitosan, samt tvärbindning av kitosan med framgång. En beläggning baserad på sådan biopolymer-nanokomposit framställs på rostfritt stål och undersöks med avseende på dess korrosionsegenskaper. Framtida arbete kommer att bestå i att välja en lämplig storlek av pollen som en mikrobehållare för att förbättra beläggningens integritet, och så småningom förse beläggningen med tre-i-ett-funktionen, dvs.antikorrosion, antimikrobiell och självhelande.

The cement industry accounts for 5-7% of the global emissions of carbon dioxide, where CO2 is mainly emitted during the calcination process. However, CO2 is also absorbed by all concrete products during their lifetime through the process of carbonation. Based on a carbonation calculation model, this project investigated the CO2 uptake by Benders Sverige AB products and landfills.Benders Sverige AB produces mainly paving stones and roof tiles. During the years 2011-2020, more than 56,000 tonnes of CO2 were permanently absorbed by Benders’ products in use. This uptake corresponds to 9% of calcination emissions released during cement production. Roof tiles stand for &gt;77% of the CO2 uptake, which is most likely due to their high surface to volume ratio, which facilitates carbonation. Furthermore, roof tiles are surrounded by air whereas paving stones are mostly carbonated from their topside.It was also investigated how surface treatments affect the carbonation of roof tiles. A phenolphthalein test showed that surface treatments generally reduce carbonation, but since roof tiles are also carbonated from their underside it is possible that even surface treated roof tiles will be fully carbonated during their service life.To calculate the CO2 uptake of a concrete landfill, a hypothetical scenario was set up. The calculations show that there is a big potential in the optimisation of landfills to increase carbonation and therewith decrease the CO2 net emissions of Benders Sverige AB.