The processes that govern the formation, existence and consumption of ions in gases have been studied both experimentally and theoretically. The aim of the work is targeted at increasing the understanding of these phenomena in the working gases inside an engine. Both the cause and the application of ionized gases inside the cylinder of a spark ignited (SI) engine has been studied. The spark disch

Lignin is a potential biofuel which can be extracted from kraft cooking liquor. Lignin can also prove valuable as a speciality chemical. By extracting lignin potential economical revenue can be gained by pulp mills, as well as technical benefits such as easier delignification and bleaching. The subject of this work was the extraction of lignin from kraft cooking liquor using ceramic ultrafiltrati

A thermodynamic model for electrolyte solutions has been derived for binary and multicomponent solutions up to very high molalities. The model was extensively tested on 163 binary aqueous electrolyte systems up to very high molalities, and the results show that the model represents mean ionic activity coefficients and osmotic coefficients very accurately. The model parameters vary significantly be

This thesis deals with Maya religion and history. The Books of Chilam Balam is the collective title of a body of texts ascribed to the Jaguar Prophet. They are written in the Yucatec Maya language, and tell the reader about Yucatec Maya cosmology, rituals, prophecies, calendars, medicine and they are as well considered as Yucatec Maya emic historiography. These manuscripts are considered enigmatic

The mean by which a gas turbine combustor is cooled is of major importance for the efficiency and emission performance of the machine. The trends of increasing top cycle temperature and leaner combustion have also been accompanied by a need of efficient use of the cooling air. Traditional cooling schemes such as film cooling are associated with high coolant flow rates and unacceptable emission lev

One of the noticeable trends in recent years is that products have received increasing attention in environmental policy. The focus on products and their life cycle impacts is often referred to as ?life cycle thinking?. This implies a shift away from the traditional focus on production processes and the environmental impacts of point-source pollution, towards a stronger focus on emissions from the

This thesis has the main focus on ways to improve the blood perfusion estimate, as obtained from a continuous wave Doppler system. Earlier studies have shown large temporal variations in the detected perfusion estimate, due to speckle. Here, a theoretical model to predict frequency dependent characteristics of speckle in continuous wave ultrasound is presented. The model predicts the frequency shi

Higher education is facing a range of major challenges during the twenty-first century. Personalised, flexible and open learning are considered among the driving forces, thus, issues of quality must be urgently addressed.This qualitative, multiple-case-study research with single and cross-case analysis focuses on benchmarking e-learning in higher education. The results of this study include provid

Firms compete with each other to earn the highest profit. A wide range of issues needs to be considered in order to do so – decisions about products, markets, customers and, not to forget, organisation have to be made. Concerning organisation, a business firm can choose to make a particular thing (a good or service) by itself or to buy it from someone else. The decision determines the way in which

Helicobacter pylori is a human pathogen strongly associated with chronic type B gastritis, peptic ulcer disease, gastric cancer and MALT lymphoma. Our aims were to establish a mouse model of H. pylori infection, to study pathogenesis of gastritis and gastric cancer and to investigate new treatment strategies in this model. Both spiral and coccoid forms of H. pylori strains 17874, 25 and 553/93 cau

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

The crystalline properties of starch constitutes a puzzling area of research. Our understanding of the crystalline structure of amylopectin, that is the crystalline component in starch, is based on the observations from investigations on modified amylose. The first part of this thesis includes a discussion of the unit cells (the smallest crystalline units) suggested in the literature. The differen

Tortuguero National Park in Costa Rica hosts nesting by four species of highly migratory and endangered sea turtles (green, hawksbill, leatherback and loggerhead turtles). Sea turtle research at Tortuguero has been continuous since Dr. Archie Carr began studies in the 1950?s. This dissertation aims to clarify the Tortuguero sea turtles? post-nesting migrations, nesting trends and survival threats.

The modification of drugs into pro-drugs is an attractive concept allowing you to tweak the chemical and physical properties of a drug without changing the original structure of the active compound. In principle, any compound possessing a preferred biological activity can be transformed into a pro-drug. Many natural products harbor qualities that are potentially interesting as drugs but difficult

The migratory behaviour of birds has received much scientific interest, though many questions still remain unsolved. One of the reasons for this is the difficulty of following the birds as they move between breeding and wintering localities. Populations may mix on migration and the origin of individual birds is difficult to assess. One way to address this problem may be to develop genetic populati

During production of concentrated fruit juices, both physical and chemical losses of aroma compounds occur due to heat treatment such as pasteurisation and evaporation. This leads to an inferior quality of the final product. By recovering the aroma complex from fresh juice and then adding it back to the processed juice, heat treatment can be avoided. Hydrophobic pervaporation is an emerging membr

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