Syftet med forskningen som presenteras i denna avhandling är att vidareutveckla tillgänglighetsområdet i riktning mot en större perspektivrikedom. Avhandlingen baseras på kulturhistorisk aktivitetsteori (CHAT). Den analyserar en systemisk helhet utifrån sådana mänskliga, artefaktuella och naturliga faktorer som påverkar en individs handlingsmöjligheter i konkreta situationer.Avhandlingen har två h

Background: Skin cancer incidence is rapidly increasing. The main risk factor, sun exposure, can be modified. Informational campaigns can be effective in raising skin cancer awareness and target the high-risk population. Still, sun exposure habits in people at high risk of skin cancer are not well-known.Objective: To investigate if and how sun exposure habits differ between low-risk and high-risk

This thesis deals with the general problem of controlling rigid-body systems through space, with a special focus on unmanned aerial vehicles (UAVs). Several promising UAV control algorithms have been developed over the past decades, enabling truly astounding feats of agility when combined with modern sensing technologies. However, these control algorithms typically come without global stability gu

Airborne wear particle emission has been investigated in a pin-on-disc tribometer equipped with particle analysis equipment. The pins are cut out fromcommercial powder metallurgy automotive brake pads as with and without copper content. The discs are cut out from a commercial grey cast iron automotive brake disc as cut out and as in addition to a laser cladded with a powder mix of Ni-self fluxing

Black carbon, as a series of light-absorbing carbonaceous material, contributes significantly to current global warming. Black carbon has always been considered a product of incomplete combustion of fossil fuels and vegetation. In the road transport sector, combustion exhaust is thought to be the primary source of black carbon. This study uses a pin-on-disc tribometer to simulate automotive disc b

Artificial football turf is today an increasingly common playing surface for athletics and kids. Its environmental impact is much debated, which is ranked as the second most common source of micro-plastic migration into nature. There are also concerns regarding the spread of inhalable airborne particles, originating from the wear between the football shoe-artificial turf contact. In this study a B

This article describes how a wheel–rail wear detection parameter based on noise was developed by running a rapid transit train instrumented with microphones in a depot with a small curve radius. This full-scale test made use of previous knowledge gained from lab-scale tests. The lab- and full-scale tests showed that noise could be used as an indicator of wear transition, when normal wear turns int

The abrasive wear behavior of traditional compacted graphite cast iron (CGI) and compacted graphite cast iron with 0.1% tin addition (CGI–Sn) is studied using a pin-on-disk tribometer. The microstructures of these two CGIs were observed by optical microscopy and scanning electron microscopy. The results show that Sn reduces the average size of vermicular graphite and promotes the generation of pea

Studded tyres wear surfaces of winter roads, generating inhalable airborne particles. In this study, four concrete road materials and two stud geometries were investigated in terms of wear, road material hardness and airborne particle concentration. The sliding contact between studded tyres and road materials was studied using a pin-on-disc machine in a clean chamber. The results show that the nor

A pin-on-disc tribometer placed in a one-way ventilated chamber was used to investigate the effect of relative humidity on the tribology and airborne particle emission of three commercial railway brake block materials (grey cast iron, organic composite, and sintered). Cast iron showed the highest friction coefficient, particle emission and wear loss and organic composite exhibited the lowest. The

The tiny contact zone (approximately 1 cm2) where steel wheel meets steel rail is fundamental to rail transport. This work is a comprehensive presentation of recent research in wheel-rail contact tribology. It stresses that, unlike gears or rolling bearings which are sealed contacts with reduced exposure to the surrounding environment, a wheel-rail contact is an open system that is exposed to dirt

The tribology of an open system at temperatures ranging between 3 °C and -35 °C, with and without snow, was investigated using a pin-on-disc tribometer mounted in a temperature-controlled environmental chamber. The relationship between the microstructure and ductility of the materials and the tribology at the contacting surfaces was investigated. The study shows that during continuous sliding, pre

The purpose of this work-package within the Quiet-track, FP7, is to develop a noise related track maintenance tool, in the form of an on-board measurement system. As a first step, lab scale tests using a pin-on-disc tribometer were used in order to distinguish how noise changes when the wear mechanism in a sliding contact shifts from normal wear to severe and catastrophic wear. Once the potential

This experiment investigated the effect of tin in an amount up to 0·121 wt-% on the microstructure and mechanical properties of compacted graphite iron. Graphite and matrix evolution was emphasised with the help of scanning electron microscopy. The results indicate that Sn in experimental range reduces graphite size. Pearlite quantity would increase with the increasing Sn and reaches over 95% when

Ni-based composite coatings containing varied contents of tungsten carbides on low carbon steel were fabricated. Effects of sintering temperature and tungsten carbides contents on the surface, interface, microstructure and wear resistance of the coatings were investigated using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Vickers microhardness tester, bulk

Noise from the wheel-rail interface is a troublesome side effect when railway vehicles negotiate rail curves. In this laboratory study, two pin-on-disc tribometers were used to simulate the pure sliding process in the wheel-rail contact. The purpose was to investigate the relationships between surface topographies, tribological aspects and the emitted noise. Five different surface topographies man

Fe-based composite coatings were fabricated on Q235 steel substrate by plasma cladding. B4C particles were injected at the center and edge of the melting pool as strengthening phase. Scanning electron microscopy and pin-on-disc tribometer were applied to study the microstructure and wear resistance of the coatings. The results showed that the central injected B4C particles dissolved during plasma

Railways operate in an open environment where temperature, humidity, and the oxidation conditions are subjected to change. An experimental investigation used a pin-on-disc machine to examine the influence of environmental conditions and iron oxides on the wear performance of the wheel-rail contact. The wear mechanisms were analyzed using scanning electron microscopy and found to be highly dependen