Introduktion: Dental erosion definieras som förlust av tandens hårdvävnad genom en kemisk process som inte involverar bakterier. Dagens förändrade livsstil och kosthållning medför att våra tänder oftare utsätts för kemisk påverkan som kan leda till erosion. Det är flera faktorer som samverkar och dental erosion har en multifaktoriell etiologi.Syfte: Syftet är att beskriva olika registreringsmetoder för dental erosion.Frågeställningar: Vilka metoder kan användas för registrering av initial erosion? Vilka metoder kan användas för registrering av avancerad erosionsskada? Vilka metoder är kliniskt beprövade på patient?Metod: LitteraturstudieResultat: Ett flertal registreringsmetoder fanns beskrivna i litteraturen, merparten var inte applicerbara kliniskt. Registeringsmetoderna som framgick i den beskrivande litteraturstudien var: 3D scanning microscope (IFM), Atomic absorption spectroscopy (AAS), Digital photography (DP), Focus-variation 3D microscopy (FVM), Longitudinal microradiography (LMR), Non-contact confocal laser scanning microscopy (CLSM), Optical assessment, Optical profilometry (OP), Quantitative light-induced fluorescence (QLF), Scanning electron microscopy (SEM), Stylus profilometry (SP), Ultrasound, White light interferometry (WLI) och X-ray diffraction (XRD).Konklusion: Vid registrering av initial erosion krävs analys av tandytans mineralinnehåll samt optiska analyser med hjälp av instrument.

Reducing the CO2-pollution, resulting from the combustion of fossil coal for energyproduction, is important to affect environmental changes. One way to achieve a reductionis to use the oxy-fuel technology. The technology uses O2 and re-circulated flue gasduring the combustion which results in a flue gas mainly consisting of CO2. The flue gascould then be compressed and stored without environmental effects. A problem thatfollows from the compression is the risk of acidification in sensitive parts of the process.Acidification can occur because of reactions following from the contact of condensedwater and sulphur- and nitrogen-oxides which are also present in the flue gas.This report compiles and evaluates the basis of a scientific unit with the purpose ofexploring the possibilities of extracting impurities of SOx and NOx from the flue gases.The dimensions of the unit are based on basic conditions, defined for an existing oxy-fuelprocess at Chalmers, and on the results of computer modelling.

This report is the result of a thesis work in Integrated Product Development, regarding hygienic features in dishwashers and especially disinfection by the use of steam.The thesis is performed at Electrolux Primary Development Dishcare in Stockholm and in collaboration with the Department of Machine Design at the Royal Institute of Technology.The targets of the thesis are to prove the advantages of a technology suitable to implement as a hygienic feature inside a dishwasher and to realize a functional prototype of a differentiated hygienic feature that does not exist on the market today.The process followed to perform the thesis is the process defined for Electrolux Primary Development.The technology chosen for development is disinfection by heating the water on the surface of the dishware, by the use of steam.A number of tests on how steam behaves when injected into the dishwasher tub have been performed, providing the results that have been taken in consideration when designing the prototype.The prototype consists of a pipe system provided with nozzles to eject the steam into the upper parts of the dishwasher. Tests of the final prototype show that thermal disinfection of water in a dedicated area of the tub can be reached within 9 minutes. The operation requires 0,17 liters of water and consumes 0.2kWh..

The purpose of this master's thesis is to investigate how the students at Chalmers University of Technology at Lindholmen in Gothenburg use libraries in their schoolwork. The empirical material consists of the answers of questionnaires that were handed out to two classes of students, on the second year of their education. To illustrate the topic there are a theoretical frame and examples of earlier studies. The theoretical frame is Limbergs texts that deal with for example information seeking and how important it is in all education. The earlier studies are about student's different ways of using libraries.

The agricultural sector is currently highly dependent on fossil fuels, with diesel beingmost prominent. There are however both historical and modern alternatives thathave not been subject to enough evaluation to disregard them as suitable alternative.This report aims to theoretically investigate the feasibility of converting aconventional diesel driven tractor to run on electricity, delivered via a cableconnected to either the main power grid or on-site electric production, such asphotovoltaic. Delivering electricity to the machine via a cable is a method withhistorical roots in the early 20th century and in the present day mining industry.The economic and technological potential of the technique are evaluated, along withthe examination of several different motor powers, voltages, losses and constructionideas. The report finds the technique to be both possible as well as long termeconomically and environmentally beneficial. To realise this method however, somedeviations from the present methods of agricultural farming must be made,considering the more advanced driving patterns, the limited mobility and therequirement for extra driver awareness.

Vid hja?rtoperationer leder man bort blodet fra?n hja?rtat och kopplar upp patienten till en hja?rt-lungmaskin med tillho?rande beha?llare (kardiotomi-reservoar). I det o?ppna sa?ret tillfo?rs koldioxid kontinuerligt. Detta go?rs fo?r att avlufta sa?rha?lan och hindra luft fra?n att komma in i hja?rtat och de stora ka?rlen under kirurgi.

Information about vibration injuries as a preventive measure is beneficial to society as well as the individual. As early as after a few years work with machines that vibrate can cause young sensitive persons to develop vibration injuries.An evaluation has been done on a web page with focus on information about work related vibration injuries. As a part of the evaluation a user observation and interview study was performed with workers who worked in different occupations. The workers all used machine that vibrate as part of the work. A total of eleven workers participated in the study.

Reducing the CO2-pollution, resulting from the combustion of fossil coal for energyproduction, is important to affect environmental changes. One way to achieve a reductionis to use the oxy-fuel technology. The technology uses O2 and re-circulated flue gasduring the combustion which results in a flue gas mainly consisting of CO2. The flue gascould then be compressed and stored without environmental effects. A problem thatfollows from the compression is the risk of acidification in sensitive parts of the process.Acidification can occur because of reactions following from the contact of condensedwater and sulphur- and nitrogen-oxides which are also present in the flue gas.This report compiles and evaluates the basis of a scientific unit with the purpose ofexploring the possibilities of extracting impurities of SOx and NOx from the flue gases.The dimensions of the unit are based on basic conditions, defined for an existing oxy-fuelprocess at Chalmers, and on the results of computer modelling.

Climate change is expected to lead to increased rainfall and higher temperatures, among other things. This will have a major impact on our cities. Floods can lead to property damage as well as damages to human and animal health. Higher temperatures will increase the frequency of heat-related health risks and premature deaths. The consequences of climate change will be particularly large in our cities because of the city's morphology with a high amount of paved surfaces and buildings that affect the natural processes in areas such as drainage and absorption of solar radiation.

Bacteria are a problem that occurs naturally in dishwashers when the dish stands there dirty for an extended period of time. To get rid of the unpleasant smell that the bacteria is causing, the most common solution is to run a regular washingcycle which can cause problems for the environmentally-conscious consumers since this causes unnecessary energy waste and emissions of chemicals in the washwater. To solve the problem in a more environmentally-friendly way by directly attacking the bacteria with an appropriate bacterialreductionmethod can therefore be an attractive feature in a dishwasher. There are many different ways to treat surfaces that have been exposed to the bacteria. Some high-profile methods are UV-radiation, microwaves and oxidant (ozone) that all three have had success in reducing bacteria in different contexts.

This master thesis project at KTH is performed in the Mechanical and Aerospace Engineeringdepartment at University of Florida (UF). The thesis is a small part of a gas turbine researchproject where a vapour absorption refrigeration system (VARS) and a high pressure regenerativeturbine engine (HPRTE) are integrated together. The main objective is to build a computermodel of the VARS. The computer model is supposed to be used to analyse the off-designperformance of the VARS and should also be easy to integrate as a subroutine in a more complexsystem model. To model the VARS some knowledge of the absorbent/refrigerant mixture had tobe well known, in this case a mixture of ammonia and water.

An investigation of the heat impact of laser cutting on the material properties when producing tensile and impact test specimens of different steel types of varying thickness has been performed. The purpose of the thesis project was to provide recommendations regarding how much material that needs to be milled from the laser cut edge before tensile and impact tests. The study has been performed partly by investigating the test specimens by heat camera when the specimens were cut in the laser cutting line and partly by performing hardness tests, investigation by microscopy, and tolerance and roughness measurements and tensile tests of the laser cut material and material produced in the traditional multi operation machine. The results show that the heat affected zone in the thicker materials is greater than previously thought of, and that the currently used recommendation has to be adjusted. The study clearly shows that the thicker the material, the greater the heat affected zone, independently of the steel type, since the thicker material takes longer time to cut.

Approximately 20% of the milk within the udder of a cow is stored in the cistern and immediately available for milk removal, while activation of the milk ejection reflex is required for removing the remaining milk stored in the alveolar compartment. The aim of this literature review is to describe, evaluate and consider implications of the three different suckling activities that the calf displays during a suckling bout. In terms of milking, these phases are represented by pre-stimulation, stimulation during milking and post-stimulation. Pre-stimulation is commonly performed in order to induce the milk ejection reflex, whereby the hormone oxytocin is released and the alveoli in the secretory tissue are contracted. Time requirements regarding pre-stimulation must be considered in relation to lactation stage and milking interval.

Nuvarande riktlinjer för hur man skall bedöma och klassificera risken för att skador skall uppstå då hand- armsystemet utsätts för vibrationer är baserade på en enkel frekvensviktningskurva. Problemet med dagens rådande standard är att den inte tar hänsyn till alla de faktorer som inverkar på risken med vibrerande handhållna verktyg, t.ex. påverkan av transienter i vibrationerna eller mängden energi som absorberas av hand- armsystemet. Ett annat problem med standarden är att karaktärisering utifrån den tenderar att bli metodoberoende beroende på vilken analysmetod som väljs. Ett sätt att ta hänsyn till fler av de bidragande faktorerna är att använda andra analysmetoder, än de som används i enlighet med rådande standard, som till exempel vibration power absorption eller analytisk wavelettransform.

The effect of climate change places demands on how we build cities. Cities have to be built denser to meet the objectives of sustainability but as a result of this densification city green areas are at risk of exploitationand disappearing. The question this raises is whether there has to be an opposition between a dense and a green city?Urban trees are playing a very important role in cities. They stand as the major part of the vegetation in citieswhich are otherwise dominated with concrete and stone.