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- Jansson, Ida
(författare)
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The effect of flowing water on turbine rotor vibrations
- 2010
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is a lack of standardized rules on how the fluid in the turbine should be included in rotor models of hydraulic machinery. This thesis is an attempt to shed some light on this issue. We approach the problem from two viewpoints, situated at place at a hydropower plant and by mathematical analysis.One goal of the thesis is to develop a measurement system that monitors the instantaneous pressure at several locations of a runner blade on a 10 MW Kaplan prototype in Porjus along Lule river. Paper A outlines the development of the measurement system and the instrumentation of the runner blade. Miniature piezo-resisitive pressure transducers were mounted flush to the surface. If instrumentation is successful, the pressure field of the runner blade could be measured simultaneously as the loads and displacements of the guide bearings and the generator.The second objective is concerned with how the motion-induced fluid force affects the dynamic behaviour of the rotor. Inertia and angular momentum of the fluid and shrouding are expected to influence the dynamic behaviour of the turbine. Paper B scrutinizes this assumption by presenting a simple fluid-rotor model that captures the effects of inertia and angular momentum of the fluid on the motion of a confined cylinder. The simplicity of the model allows for powerful analytical solution methods. The results show that fluid inertia, angular momentum and shrouding of hydraulic turbines could have substantial effects on lateral rotor vibrations. This calls for further investigation with a more complex fluid-rotor model that accounts for flexural bending modes.
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- Jansson, Jenny, 1979-
(författare)
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Manufacturing Consensus : The Making of the Swedish Reformist Working Class
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The 1910s were a precarious time for the labor movement. The Russian Revolution in 1917 sparked a trend towards radicalization among labor organizations and communist organizations spread all over Europe. These organizations challenged existing notions of the “worker,” causing an identity crisis in class organizations. Suddenly, there were not only workers, but different kinds of workers, promoting not only social democracy and syndicalism, but also communism. The labor movement became fragmented. This was very much the case in Sweden. However, despite the conflict situation during the interwar period, the Swedish workers were integrated into a strong cohesive labor movement, united under the banner of reformism which, in turn, paved the way for a strong social democracy.How was this possible? This study presents an explanation of why the Swedish working class so unanimously adopted reformism. Its thesis is that the leadership of the Trade Union Confederation (LO) was well aware of the identity problems the leftwing factions had created for the reformist unions. Because of this, the leadership decided to take actions. As “identity entrepreneurs” the leaders re-formed the notion of the worker by constructing an organizational identity that downplayed class struggle and embraced discipline, peaceful solutions to labor market problems, and cooperation with the employers. This notion was inculcated in the workers through popular education. The book shows that ABF study circles became the main tool of the Trade Union Confederation’s identity policy in the 1920s and 1930s and its successful outcome paved the way for the renowned “Swedish Model.”
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- Petzäll, Kerstin, et al.
(författare)
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Time saved with high speed driving of ambulances
- 2010
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Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575 .- 1879-2057. ; 43:3, s. 818-822
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Tidskriftsartikel (refereegranskat)abstract
- Transportation with road ambulances is increasing because of a concentration of hospitals to larger units, with high quality in the acute care of the patients. The concentration implies longer distances to receiving units, which increases the transportation time. The purpose of the present study was to investigate the time difference in ambulance transportation with high speed emergency driving, compared to non-emergency driving in normal traffic pace. Data was collected from 30 emergency high speed ambulance transportations in urban and rural areas. These transportations were then repeated experimentally with an ambulance driving at normal traffic pace. The average speed and duration for the emergency transportations were shorter than for the experimental driving, both in urban and rural areas. The mean time saved was 2.9 min (urban areas) and 8.9 min (rural areas). Regardless of the patient's clinical status or need of care the emergency transportations were carried out in higher speed than the experimental driving. However, patients with life threatening conditions were not included in this study. Procedures and methods should be developed to identify the patients for which fast transportation has clinical relevance to the outcomes.
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- Riehm, Mats, et al.
(författare)
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Ice formation detection on road surfaces using infrared thermometry
- 2012
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Ingår i: Cold Regions Science and Technology. - : Elsevier BV. - 0165-232X .- 1872-7441. ; 83-84, s. 71-76
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Tidskriftsartikel (refereegranskat)abstract
- Ice formation on roads causes hazardous conditions due to reduction of road surface friction. Forecasting, detecting and preventing ice formation are therefore of high importance for winter road maintenance personnel. Advanced sensors for detecting road ice exist, but there is a demand for more cost-effective technologies. A method for detection of road surface ice formation based on remote temperature measurements with infrared thermometers is presented. Freezing events were detected based on the temperature dynamics that result from the exothermic reaction as water freezes. Experimental measurements in a climate chamber and in field conditions showed that ice formation often causes a distinct temperature pattern, which could easily be identified and distinguished from other temperature fluctuations. The method is promising as a cost-effective technique suitable for several applications in cold regions where detection of ice formation is important. (C) 2012 Elsevier B.V. All rights reserved.
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