| 1. |
- Nicholls, Ian A., et al.
(författare)
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Theoretical and Computational Strategies for Rational Molecularly Imprinted Polymer Design
- 2009
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Ingår i: Biosensors & bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 25:3, s. 543-552
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Tidskriftsartikel (refereegranskat)abstract
- The further evolution of molecularly imprinted polymer science and technology necessitates the development of robust predictive tools capable of handling the complexity of molecular imprinting systems. A combination of the rapid growth in computer power over the past decade and significant software developments have opened new possibilities for simulating aspects of the complex molecular imprinting process. We present here a survey of the current status of the use of in silico-based approaches to aspects of molecular imprinting. Finally, we highlight areas where ongoing and future efforts should yield information critical to our understanding of the underlying mechanisms sufficient to permit the rational design of molecularly imprinted polymers.
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| 2. |
- Danestig, Maria, 1965-
(författare)
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Efficient heat supply and use from an energy-system and climate perspective
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to illustrate whether the heat demand in district heating systems can be seen as a resource that enables efficient energy utilization, how this can be achieved and to discuss consequences of this assumption. Based on the answers to posed research questions and on the studies included in this thesis, it is concluded that the hypothesis “A common system approach for energy supply and heat demand will show climate and economic efficient solutions” is true.In cold-climate countries, energy for heating of buildings is essential and heating options that interplay with the power system through electricity use or generation have potential for efficiency improvements. In Sweden, district heating is used extensively, especially in large buildings but to a growing extent also for small houses. Some industrial heat loads and absorption cooling can complement space heating demand so that the production resources may be more evenly utilised during the seasons of the year.Rising electricity prices in recent years cause problems for the extensive use of electric heating in Sweden and further switching to district heating should be a possible option. To be economically favourable, district-heating systems require a certain heat load density. New low-energy houses and energy-efficiency measures in existing buildings decrease the heat demand in buildings and, thus, in district heating systems. Optimisation models have been used in several studies of large, complex energy systems. Such models allow scenarios with changing policy instruments and changed consumer behaviour to be analysed. Energy efficiency measures as well as good conditions for efficient electricity generation, which can replace old, inefficient plants, are needed to reduce carbon dioxide emissions from the energy sector.Results when having a European energy perspective to studies of changes in Sweden differ from when having for example a Swedish energy system perspective The effects on global carbon dioxide emissions, when studying combined heat and power electricity generation in Sweden, are greater than it is on local emissions.
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| 3. |
- Karlsson, Ingrid, 1948-
(författare)
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Att leda i kommunal äldreomsorg : Om arbetsledares handlingsutrymme, handlingsfrihet och skilda lojaliteter - exemplet Halland
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The middle management position in the care of the elderly is the focus of this licentiate dissertation. The aim was to develop knowledge about the constraints within which the middle manager is able to act and which freedom of action he/she has. The empirical data consisted of 17 interviews and a vignette study completed by 47 middle managers in social care in the county of Halland. The managers' perceptions of what exerts a control on their work and of the type of control that is exercised was investigated into in the interviews. In the vignette study, using three specific cases, the focus was on the research issue, i.e. how they thought they could act, mainly in terms of their apprehensions of constraints (the formal framework) within which to act and the freedom of action. Further, aspects of loyalty were analysed. It comes down to a view of what can be done and how it can be carried out. The middle managers' freedom was violated by control mechanisms that had a disciplinary cognitive orientation as well as mechanisms that constituted a normative control, such as budget issues and legislation. They described, mainly in the interviews, their experiences of being in a vulnerable position and of being trapped between interested parties. On the other hand the vignette study revealed an emphasis on being a manager and conveyed an administrative approach. By adopting this approach the middle managers relinquish to some extent their moral responsibility. A moral indignation is apparent, however, when the consequences for the workplace and the staff become serious as it does in one of the vignettes. Then the indignation in many cases passed on into a deliberation about quitting. The administrative concentration of middle management can, in its extension, lead to the need for an old group to re-enter into the field of the elderly care, namely, the assistant manager. In other words, a new intermediate level emerges that takes care of this dilemma of being trapped between the interested parties from a bottom up perspective. It is possible here to make a comparison with what in modern terms is called shared leadership.
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| 4. |
- Karlsson, Johannes, et al.
(författare)
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Cloud radiative forcing of subtropical low level clouds in global models
- 2008
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Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 30:7-8, s. 779-788
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Tidskriftsartikel (refereegranskat)abstract
- Simulations of subtropical marine low clouds and their radiative properties by nine coupled oceanatmosphere climate models participating in the fourth assesment report (AR4) of the intergovernmental panel on climate change (IPCC) are analyzed. Satellite observations of cloudiness and radiative fluxes at the top of the atmosphere (TOA) are utilized for comparison. The analysis is confined to the marine subtropics in an attempt to isolate low cloudiness from tropical convective systems. All analyzed models have a negative bias in the low cloud fraction (model mean bias of –15%). On the other hand, the models show an excess of cloud radiative cooling in the region (model mean excess of 13 W m–2). The latter bias is shown to mainly originate from too much shortwave reflection by the models clouds rather than biases in the clear-sky fluxes. These results confirm earlier studies, thus no major progress in simulating the marine subtropical clouds is noted. As a consequence of the combination of these two biases, this study suggests that all investigated models are likely to overestimate the radiative response to changes in low level subtropical cloudiness.
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| 5. |
- Karlsson, Johannes, 1978-
(författare)
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The influence of clouds on Earth's radiation budget in global climate models
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Considering the high sensitivity of climate to changes in cloudiness, the way clouds might change in a perturbed climate is important for the total temperature response. In fact, the cloud feedback has been identified as the main uncertainty in future projections, as simulated by global climate models. To increase the confidence of future scenario simulations it is necessary, although not sufficient, that the models manage to represent the present-day climate in a realistic manner. We compare the simulations of cloudiness to available observations in the marine subtropics and the Arctic, two regions in which changes in cloudiness are believed to have large impact on the climate. In terms of the annual cycle of Arctic cloud properties, climate models show large disagreement with each other and with observations. There exists a tentative across-model relationship, such that models with higher amounts of clouds in the winter are also associated with larger surface cloud forcing. However, across-model differences in the wintertime surface cloud forcing cannot explain differences in the simulated surface temperatures. Rather, we identify across-model differences in temperature and moisture properties of the air entering the Arctic region to be of greater importance. We find that climate models in general underestimate the amount of low clouds in the marine subtropics but still overestimate the regional averaged cloud radiative cooling. As a consequence we suggest that models are likely to overestimate the radiative response to changes in the cloudiness. We also demonstrate the potential of satellite derived cloud top heights to be used as model diagnostics in the climatologically important transition from stratus-topped to cumulus-topped marine boundary layers in the subtropics.
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| 6. |
- Karlsson, Magnus, et al.
(författare)
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Regional energy system optimization - Potential for a regional heat market
- 2009
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 86:4, s. 441-451
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Tidskriftsartikel (refereegranskat)abstract
- Energy supply companies and industrial plants are likely to face new situations due to, for example, the introduction of new energy legislation, increased fuel prices and increased environmental awareness. These new prerequisites provide companies with new challenges but also new possibilities from which to benefit. Increased energy efficiency within companies and increased cooperation between different operators are two alternatives to meet the new conditions. A region characterized by a high density of energy-intensive processes is used in this study to find the economic potential of connecting three industrial plants and four energy companies, within three local district heating systems, to a regional heat market, in which different operators provide heat to a joint district heating grid. Also, different investment alternatives are studied. The results show that the economical potential for a heat market amounts to between 5 and 26 million EUR/year with payback times ranging from two to eleven years. However, the investment costs and the net benefit for the total system need to be allotted to the different operators, as they benefit economically to different extents from the introduction of a heat market. It is also shown that the emissions of CO2 from the joint system would decrease compared to separate operation of the systems. However, the valuation of CO2 emissions from electricity production is important as the difference of emitted CO2 between the accounting methods exceeds 650 kton/year for some scenarios.
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| 7. |
- Marsh, Ian, 1965-
(författare)
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Quality aspects of internet telephony
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Internet telephony has had a tremendous impact on how people communicate.Many now maintain contact using some form of Internet telephony.Therefore the motivation for this work has been to address the quality aspectsof real-world Internet telephony for both fixed and wireless telecommunication.The focus has been on the quality aspects of voice communication,since poor quality leads often to user dissatisfaction. The scope of the workhas been broad in order to address the main factors within IP-based voicecommunication.The first four chapters of this dissertation constitute the backgroundmaterial. The first chapter outlines where Internet telephony is deployedtoday. It also motivates the topics and techniques used in this research.The second chapter provides the background on Internet telephony includingsignalling, speech coding and voice Internetworking. The third chapterfocuses solely on quality measures for packetised voice systems and finallythe fourth chapter is devoted to the history of voice research.The appendix of this dissertation constitutes the research contributions.It includes an examination of the access network, focusing on how calls are multiplexed in wired and wireless systems. Subsequently in the wireless case, we consider how to handover calls from 802.11 networks to the cellularinfrastructure. We then consider the Internet backbone where most of ourwork is devoted to measurements specifically for Internet telephony. The applications of these measurements have been estimating telephony arrival processes, measuring call quality, and quantifying the trend in Internet telephony quality over several years. We also consider the end systems, since they are responsible for reconstructing a voice stream given loss and delay constraints. Finally we estimate voice quality using the ITU proposal PESQ and the packet loss process.The main contribution of this work is a systematic examination of Internet telephony. We describe several methods to enable adaptable solutions for maintaining consistent voice quality. We have also found that relatively small technical changes can lead to substantial user quality improvements.A second contribution of this work is a suite of software tools designed to a certain voice quality in IP networks. Some of these tools are in use within commercial systems today.
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| 8. |
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| 9. |
- Skyllberg, Ulf, et al.
(författare)
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Net Methylmercury Production as a Basis for Improved Risk Assessment of Mercury-contaminated Sediments
- 2007
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Ingår i: AMBIO: A Journal of the Human Environment. ; 36:6, s. 437-42
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Tidskriftsartikel (refereegranskat)abstract
- Sediments contaminated by various sources of mercury (Hg) were studied at 8 sites in Sweden covering wide ranges of climate, salinity, and sediment types. At all sites, biota (plankton, sediment living organisms, and fish) showed enhanced concentrations of Hg relative to corresponding organisms at nearby reference sites. The key process determining the risk at these sites is the net transformation of inorganic Hg to the highly toxic and bioavailable methylmercury (MeHg). Accordingly, Hg concentrations in Perca fluviatilis were more strongly correlated to MeHg (p < 0.05) than to inorganic Hg concentrations in the sediments. At all sites, except one, concentrations of inorganic Hg (2–55 μg g−1) in sediments were significantly, positively correlated to the concentration of MeHg (4–90 ng g−1). The MeHg/Hg ratio (which is assumed to reflect the net production of MeHg normalized to the Hg concentration) varied widely among sites. The highest MeHg/Hg ratios were encountered in loose-fiber sediments situated in southern freshwaters, and the lowest ratios were found in brackish-water sediments and firm, minerogenic sediments at the northernmost freshwater site. This pattern may be explained by an increased MeHg production by methylating bacteria with increasing temperature, availability of energy-rich organic matter (which is correlated with primary production), and availability of neutral Hg sulfides in the sediment pore waters. These factors therefore need to be considered when the risk associated with Hg-contaminated sediments is assessed.
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