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  • Karlsson, Olov, et al. (författare)
  • Heat treatments of high temperature dried norway spruce boards : Saccharides and furfurals in sapwood surfaces
  • 2012
  • Ingår i: BioResources. - 1930-2126 .- 1930-2126. ; 7:2, s. 2284-2299
  • Tidskriftsartikel (refereegranskat)abstract
    • Carbohydrates that migrate to wood surfaces in sapwood during drying might influence properties such as mould susceptibility and colour. Sugars on the surface of Norway spruce boards during various heat treatments were studied. Samples (350mm×125mm×25mm) were double-stacked, facing sapwood-side outwards, and dried at 110°C to a target moisture content (MC) of 40%. Dried sub-samples (80 mm × 125 mm × 25 mm) were stacked in a similar way and further heated at 110°C and at 130°C for 12, 24, and 36 hours, respectively. Glucose, fructose, and sucrose as well as 5-hydroxymethylfurfural (HMF) and furfural in the sapwood surface layer of treated wood were analysed using HPLC (RI- and UV-detectors). Carbohydrates degraded to a lower extent at 110°C than at 130°C. Furfural and to a larger extent HMF increased with treatment period and temperature. Heat treatment led to a decrease in lightness and hue of the sapwood surface of sub-samples, while chroma increased somewhat. Furthermore, considerably faster degradation (within a few minutes) of the carbohydrates on the surface of the dried spruce boards was observed when single sub-samples were conductively hot pressed at 200°C. Treatment period and initial MC influenced the presence of the carbohydrates in wood surface as well as colour change (ΔE ab) of the hot pressed sub-samples.
  • Karlsson, Olov, et al. (författare)
  • Presence of water-soluble compounds in thermally modified wood : carbohydrates and furfurals
  • 2012
  • Ingår i: BioResources. - 1930-2126 .- 1930-2126. ; 7:3, s. 3679-3689
  • Tidskriftsartikel (refereegranskat)abstract
    • With thermal modification, changes in properties of wood, such as the presence of VOC and water-soluble carbohydrates, may occur. Thermal modifications under saturated steam conditions (160°C or 170°C) and superheated steam conditions (170, 185, and 212°C) were investigated by analysing the presence of water-soluble 5-(hydroxymethyl)furfural (HMF), furfural, and carbohydrates in heat-treated wood. The influence of thermal modifications on Scots pine, Norway spruce, and silver birch was also studied. Furfurals were analysed using HPLC at 280 nm, while monosaccharides and water-soluble carbohydrates were determined by GC-FID as their acetylated alditiols and, after methanolysis, as their trimethylsilylated methyl-glycosides, respectively. The amount of furfurals was larger in boards thermally modified under saturated steam conditions than those treated under superheated steam conditions. Generally, more of HMF than furfural was found in the thermally modified boards. In process water, in which saturated steam conditions had been used, furfural and only traces of HMF were found. Higher content of water-soluble carbohydrates was found in boards treated in saturated steam rather than in superheated steam. After modification in saturated steam, substantial parts of the water-soluble carbohydrates were due to monosaccharides, but only traces of monosaccharides were found in boards treated under superheated steam conditions.
  • Karlsson, Olov, et al. (författare)
  • Colour stabilization of heat modified Norway spruce exposed to out-door conditions
  • 2010
  • Ingår i: Proceedings, 11th International IUFRO Wood Drying Conference. - Luleå : Luleå tekniska universitet. ; , s. 265-268
  • Konferensbidrag (refereegranskat)abstract
    • Wood boards from Norway spruce (300 mmx125mmx10mm) were heat modified in a pilot chamber corresponding to Thermowood-D quality. The surface of boards was sprayed with diluted solutions of ferrous sulphate alone or in combination with subsequent spraying of a 30% solution of hydrogen peroxide. The boards were exposed to outdoor conditions during summer 2009 (45o facing south). Colour coordinates were measured using a colorimeter.Only small changes in colour of boards were observed directly after the surface treatments. Lightness increased for boards with no surface treatments during out-door exposure (seven weeks). Increase in lightness was delayed when ferrous sulphate was applied to the board. Lightness was essentially unchanged during the out-door exposure period when ferrous sulphate and hydrogen peroxide was used to modify the wood surface (at low hydrogen peroxide charge a small increase of lightness was, however, observed). Chroma decreased for boards with surface treatments but levelled out after a couple of weeks. On the other hand a decrease in chroma of boards with no surface treatments started after about four weeks exposure. Hue increased for all the boards until the fourth week. After that hue of untreated boards and boards treated with both ferrous sulphate and hydrogen peroxide continue to increase.
  • Karlsson, Olov, et al. (författare)
  • Influence of heat transferring media on durability of thermally modified wood
  • 2011
  • Ingår i: BioResources. - 1930-2126 .- 1930-2126. ; 6:1, s. 356-372
  • Tidskriftsartikel (refereegranskat)abstract
    • Studies on the durability and dimensional stability of a series of hardwoods and softwoods after thermal modification in vegetable oils and in steam atmospheres have been performed. Mass loss after exposure to Coniophora puteana (BAM Ebw. 15) for 16 weeks was very low for European birch, European aspen, Norway spruce, and Scots pine thermally modified in a linseed oil product with preservative (for 1 hour at 200 degrees C). Fairly low mass losses were obtained for wood thermally modified in linseed-, tung-and rapeseed oil, and losses were related to the wood species. Low mass loss during rot test was also found for Norway spruce and Scots pine modified in saturated steam at 180 degrees C. Water absorption of pine and aspen was reduced by the thermal treatments and the extent of reduction was dependent on wood species and thermal modification method. Thermally modified aspen was stable during cycling climate tests, whereas pine showed considerable cracking when modified under superheated steam conditions (Thermo D). At lower modification temperature (180 degrees C) an increase in mass after modification in rapeseed oil of spruce, aspen and sapwood as well as heartwood of pine was observed, whereas at high temperature (240 degrees C) a mass loss could be found. Oil absorption in room tempered oil after thermal modification in oil was high for the more permeable aspen and pine (sapwood).
  • Karlsson, Tom S., 1979- (författare)
  • Challenging the dichotomy of management and civil service : an institutional analysis of Swedish public management
  • 2015
  • Konferensbidrag (övrigt vetenskapligt)abstract
    • In the wake of public sector reforms, commonly referred to as New Public Management, it has been suggested that actors engaged in public administration are changing the manner in which they understand the public sector. According to these perspectives, public reforms informed by (neo-)liberal policy have caused instances of economification and a proliferation of economy and efficiency as important and dominating norms of contemporary public organisations. In this paper I posit the question of how actors’ engaged in public administration make sense of the turbulent and pivoting reforms within the public sector? The paper is written within an institutional theoretical perspective, where both an agency- and structural perspective is engaged in order to enable a holistic analysis. The empirical material consists of four focus group sessions, in total 25 “managers” discussing issues concerning their positions and tasks associated with being engaged as public administrators within the Swedish central government. It was found that actors rejected the incompatibleness of contemporary public management on the one hand and traditional civil service on the other. Rather, actors enacted compartmentalised, yet interdependent, perspectives wherein the two mentioned roles could be used simultaneously in everyday life. On the one hand an internal perspective was enacted wherein a managerial discourse and managerial techniques were used. On the other hand an external perspective was enacted in order to safeguard citizens’ rights within the modern welfare state. It is concluded that the previously held dichotomy between management and civil service is a fallacious one. Rather than subscribing to faulty theorising surrounding a shift or a blending/merger of administrative roles, researchers of public administration should adhere to the general point made in this paper: actors engaged in public administrators are Managers as well as Civil Servants. This has great implications for the future role of public administration.
  • Karlsson, Tom S., 1979-, et al. (författare)
  • Den värdefulla ekonomen : en rapport om resurstilldelningen: en jämförelse med Danmark, Norge och Finland
  • 2010
  • Rapport (populärvet., debatt m.m.)abstract
    • Swedish higher education should be managed in a manner that secures high quality in both education and in research. A fundamental condition for acquiring such goals lies in the resources allotted to the educational institutions. The main purpose of this report is to investigate the relative resource allocation between higher education in economics and business administration within four Nordic countries (Sweden, Denmark, Norway and Finland). Within all four Nordic countries, the resource allocation for higher education in economics and business administration will be juxtaposed with the resource allocation for higher education in technology.The analysis shows that Sweden allocates 36 519 SEK per year and student within higher education for economics and business administration (compared with 82 531 SEK per year and student in higher education in technology and engineering). By setting the resource allocation of technical higher education against higher education in economics and business administration, it was found that the Swedish and Danish resource allocation systems showed high discrepancies, while the Norwegian and Finnish resource allocation systems showed low discrepancies. The Swedish resource allocation system proved to be one of low amount of allocation to higher education in economics and business administration and with high amounts of discrepancy between higher education in technology and economics and business administration.In ascending order, Finland (12 % above), Denmark (32 % above) and Norway (77 % above) all allocate resources above the levels in Sweden when it comes to the higher education in economics and business administration. The main proposition in this paper, presented firstly in the report, includes tentative causalities between allocated resources and ‘contact time’ is advanced. By assuming that the current situation between resource allocation and contact time between teachers and students are optimal and that there exists a causality between the two, this report argues for an increase of 43 % in regards of the resources to students within higher education in economics and business administration: from the current 36 519 SEK to 52 170 SEK. 
  • Karlsson, Tom S., 1979- (författare)
  • Manager and civil servant : exploring actors' taken-for-granted assumptions in public administration
  • 2014
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • Manager and Civil Servant is an exploration of actors' taken-for-granted assumptions that govern perceptions concerning how public administration should be undertaken within contemporary welfare states. It is argued that more than 30 years of continuous reforms directed towards public administration have caused dilemmas to arise. These dilemmas have resulted in a shifting of balances regarding the underpinning pillars of public administration. These reforms have furthermore resulted in an emergence of challenging social systems, entailing new beliefs and practices. The question posited is "how do actors engaged in public administration make sense of the dilemma(s) they face". Theoretically, this dissertation entails institutional theory as well as Structuration Theory. These are combined in a framework, wherein agency and structure are used in order to characterise manifestations of taken-for-granted assumptions. The framework is furthermore elaborated through conceptual perspectives concerning Management as well as Civil Service in order to model a framework for public administration. Empirically, this dissertation entails a use of qualitative as well as quantitative methods. Open-ended interviews are combined with self-administered surveys, statistical analysis, and focus groups. Two important contributions are highlighted. Firstly, actors engaged in public administration reject the idea of polarisation concerning inherent public administrative activities and that the dilemma being accentuated within public administration. As such, instances of making sense are reduced due to an unconscious enactment of meanings and sanctions that reject the presence of dilemmas. Secondly, actors' ability to reject polarisation, and thus dilemma, can be explained through compartmentalising interdependent perspectives. On the one hand actors enact an internal perspective wherein instances of Management make sense. On the other hand actors enact an external perspective wherein instances of Civil Service make sense. The separation and compartmentalisation of these perspectives not only enable actors to reject dilemma, they are enabled to enact seemingly different roles at once. They become both Managers and Civil Servants.
  • Karlsson, Tom S., 1979- (författare)
  • New public management
  • 2015
  • Ingår i: Nationalencyklopedin. - Stockholm : Nationalencyklopedin.
  • Bokkapitel (populärvet., debatt m.m.)
  • Petersen, Tom, et al. (författare)
  • The significance of fly ash in wet-dry scrubbing of SO2
  • 1988
  • Ingår i: Chemical Engineering & Technology. - : John Wiley & Sons Inc.. - 1521-4125. ; 11:1, s. 298-305
  • Tidskriftsartikel (refereegranskat)abstract
    • A bench scale flue gas desulphurization spray dry scrubbing unit was employed to study the effect of fly ash on the removal of SO2. The equipment consisted of a spray dryer with and ultrasonic nozzle for atomization and a pulse jet baghouse. The flue gas rate was 1500 lN/h (dry gas). Four fly ashes, originating from different countries were investigated. The alkalinity and reactivity of the fly ashes were determined in a pH-stat equipment. Pure fly ash removed SO2 in both the spray dryer and in the baghouse. An increase of humidity divided the fly ashes into two groups. The high calcium fly ash gave a considerably higher SO2 removal than the medium and low calcium fly ashes which showed similar SO2 removals. Fly ash did not enhance the removal of SO2 when added to a lime slurry because lime suppresses the dissolution of the alkali in the fly ashes. The pressure drop build-up in the fabric filter showed a strong dependence on material properties.
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