Sökresultat

Diesel engine developers are facing major challenges when meeting future demands on NOx and particulate emissions. The exhausts after treatment systems are rapidly improving and the technologies available in a few years will be capable of cutting emission levels close to the demanded levels. However, in order to reach the low emissions required in a long-lasting, cost effective way, the potential

The modeling work developed in this thesis can be divided in two main areas of investigations: autoignition related to spark ignition engine and combustion and emissions formation in relation to diesel engines. A first version of a detailed kinetics engine simulation program, extended to handle full cycle calculations, was employed in order to demonstrate the strong effect that nitric oxide from

This dissertation discusses the personal implications of the early consequences of rheumatoid arthritis, how they effect the person's working life and how they are dealt with. In this qualitative study thematized interviews are used. Twenty-three persons, recently diagnosed with rheumatoid arthritis, were interviewed twice, two years apart. The study is influenced by an interactionist perspective

This study attempts to answer the question of why Laban the Aramean, a rather harmless character as presented in the biblical text, is generally portrayed in rabbinic literature as a major enemy of Jacob and Israel. It is argued that the portrait of Laban as a villain developed as a result of rabbinic hermeneutics, and that the characteristics which are attributed to him in rabbinic literature wer

The present thesis deals with the activation of CO2 by insertion reactions into palladium-carbon bonds. This has been realised for the complexes {2,6-bis[(di-t-butylphosphino)methyl]benzene}palladium(II)methyl [(PCP)PdMe] and (PCP)PdCH2CHCH2. These complexes have also been used in the catalytic carboxylation of ZnMe2 and Bu3SnCH2CHCH2. Because of trans influence the palladium-methyl bond is severe

The principal purposes of the studies reported in this thesis were to develop new methods to make computerised decision support systems in medicine both more reliable and fully automated. These aims were pursued in the belief that the solution to these problems will lead to an increased clinical use of such systems resulting in benefit to both patient and physician. In the first two studies, meth

Hazardous radioactive sources out of regulatory control are referred to as orphan sources. Focussing on gamma-emitting orphan sources, this thesis describes methods that can be used in mobile gamma-ray spectrometry to perform real-time discrimination between an actual source signal and the signal due to the natural radiation background. Two categories of methods for orphan source detection are pre

The current form-giving activity in industrial design is characterized by explorations that depend on the individual capability to mentally manipulate a solution space from which to select and express the intended result. Industrial designers frequently rely on artistic experimentation, aesthetic inspiration, or design briefs. These points of departure often result in satisfactory results, but the

The aim of this work was to investigate the dosimetric effects of removing the flattening filter from conventional C-arm medical linear accelerators. In conventional linear accelerators used for radiotherapy, a flattening filter is positioned in the beam line to provide a uniform lateral dose profile at a specified depth in water. However, for some radiotherapy treatments, a uniform lateral dose p

How are access to asylum and other forms of extraterritorial protection regulated in the European Union? Is the EU acquis in these areas in conformity with international law? What tools does international law offer to solve conflicts between them? And, finally, is law capable of bridging the foundational oppositions embedded in migration and asylum issues? This work combines the potential of legal

In the last two decades, phase-contrast magnetic resonance imaging (PC-MRI) has evolved from two-dimensional velocity and flow measurements to volumetric, time-resolved depictions of velocity fields (4D PC). The acquisition of time-resolved velocity fields allows flow visualisations that might provide better understanding of the dynamics of the cardiac system. Because 4D PC is increasingly being u

In the normal functioning organism, there is a balance between cell proliferation, cell differentiation, and cell death. An imbalance in these processes results in different diseases. This thesis concerns the imbalance where there is too little cell death and cell differentiation with increased cell proliferation. The result is uncontrolled cell proliferation resulting in the development of cancer

Gel dosimetry was used together with magnetic resonance imaging (MRI) to measure three-dimensional absorbed dose distributions in radiation therapy. Two different dosimeters were studied: ferrous- and monomer gel, based on the principles of radiation-induced oxidation and polymerisation, respectively. Single clinical electron and photon beams were evaluated and gel dose distributions were mainly w

In this study, the fundamental mass and heat transfer properties of the membrane separation process called pervaporation were investigated. The suitability of pervaporation for aroma compound recovery was especially evaluated. The mass transfer in pervaporation is affected by an external mass transfer resistance in the liquid feed boundary layer, i.e. the concentration polarization phenomenon. Th

The thesis comprises an introductory chapter and four research papers. The introductory chapter provides a brief overview of recent economic growth performance in Africa, places the individual papers into a coherent context, summarizes the main findings, and discusses their relevance for economic policy. The first paper, The Role of Capital Accumulation, Adjustment and Structural Change for Take-

The recombinant DNA techniques have made it possible to produce many different proteins for a wide range of applications. The vector encoding for the recombinant protein is often inserted in the bacterium E. coli as it is a well studied and a well-known organism. To achieve a high productivity, it is important to reach a high cell density. This is obtained through fed-batch operation where the nut

It is important to decrease the burden of disease. This is in part achieved by decreasing risks. The aim of this thesis is to provide a methodology for the characterization of aerosol exposure, which may lead to negative health effects. Gases and airborne particles may cause negative health effects and the respiratory system is exceptional sensitive. Isocyanate is one group of substances that are

This thesis is about voice imitations, more specifically impersonation. Questions are raised about the uniqueness of a person’s voice and speech behaviour and if it is possible to get close to another speaker’s voice and speech. Four main research questions are investigated in different studies. The studies focus mainly on how close the imitation is to the target speaker, and addresses to a lesser

The aromatic isocyanates, toluene diisocyanate (TDI) and methylenediphenyl diisocyanate (MDI), are used in the production of polyurethane (PUR) foams, paints, elastomers and glues. The use of isocyanates is increasing, and exposure to isocyanates is the most common cause of occupational asthma. Biomarkers of TDI and MDI were determined as the corresponding amines, toluenediamine (TDA) and methyle