| 1. |
- Afzelius, Mikael, et al.
(författare)
-
Development of multipoint vibrational coherent anti-Stokes Raman spectroscopy for flame applications
- 2006
-
Ingår i: Applied Optics. - 2155-3165. ; 45:6, s. 1177-1186
-
Tidskriftsartikel (refereegranskat)abstract
- A novel technique for coherent anti-Stokes Raman spectroscopy (CARS) measurements in multiple points is presented. In a multipass cavity the pump and Stokes laser beams are multiply reflected and refocused into a measurement volume with an adjustable number of separated points along a line. This optical arrangement was used in a vibrational CARS setup with planar BOXCARS phase-matching configuration. The CARS spectra from spatially separated points were recorded at different heights on a CCD camera. Measurements of temperature profiles were carried out in the burned gas zone of a premixed one-dimensional flame to demonstrate the applicability of this method for temperature measurements in high-temperature regions. The ability to measure in flames with strong density gradients was demonstrated by simultaneous measurements of Q-branch spectra of N-2 and CO in a Wolfhard-Parker burner flame. Interference phenomena found in multipoint spectra are discussed, and possible solutions are proposed. Merits and limitations of the technique are discussed. (c) 2006 Optical Society of America.
|
|
| 2. |
- Alpkvist, Erik, et al.
(författare)
-
Simulation of nitrification of municipal wastewater in moving-bed biofilm process : approach based on a 2D continuum model for growth and detachment
- 2007
-
Ingår i: Water Science and Technology. - : Biriwa Education Services. - 0273-1223 .- 1996-9732. ; 55:8-9, s. 247-255
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a complete mathematical model of a Moving Bed biofilm process for waste-water treatment, in particular for the nitrification process. The model is based on a bottom up approach adopting a multidimensional model for the biofilm growth and metabolism and a global mass balance model for the whole reactor. The model shows that oxygen is limiting the amount of biomass involved in the nitrification process. Furthermore, it suggests the existence of an optimal amount biomass for an optimal reactor turnover rate. Studies of two specific new suspended carriers show that the model output is dependable on the geometry of the carrier, and to a satisfactory extent agreeable with measurements.
|
|
| 3. |
|
|
| 4. |
-
Annual Report 2008
- 2009. - 250
-
Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Bengtsson, Bo, et al.
(författare)
-
Hyresboendets roller - lokal organisering och boinflytande i förändring
- 2007
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Changing Roles in Rental Housing – Local Organisation and Tenant Participation in Transition Since the 1970’s a wide-ranging system of tenant participation and local organisation has developed in Sweden, based on local tenant associations(LTAs). These are the smallest organizational units within the Swedish tenant movement, which is uniquely strong, with high membership rates, institutionalised market power and considerable political influence. LTAs have been granted some influence on the management of their estates through centralised agreements between landlords and regional tenant unions.Lately these forms of tenant participation and local organisation have been challenged through centralisation within the tenant movement and an increasing general interest in alternative, less formal modes of local organisation and co-operation between landlords and tenants.Some observers foresee that the traditional forms based on LTAs and collective agreements will be successively replaced by a multitude of more informal solutions. This study investigates the validity of such claims by scrutinizing the development that has taken place in local organisation and tenant participation during the last decade or so. This is done by testing how LTAs have adjusted to the new conditions, and mapping and examining the alternative forms that have developed.The theoretical point of departure is that LTAs, as well as other local voluntary organisations of tenants, have four different roles to fulfil: (1) to function as a democratic unit for members and esidents (‘democratic community’); (2) to act as the base organisation within the tenant movement (’grass-roots organisation); (3) to represent all residents in the estate towards the landlord (’voice’); (4) to organise and support social interaction in the estate (’social organiser’).The study is based on several empirical materials, including (a) two questionnaires (1997 and 2005) directed to 350–400 chairpersons of LTAs (the sample included a panel of LTAs that received the questionnaire on both occasions); (b) a questionnaire directed to 100 tenants who are active in alternative forms of local organisation; (c) a questionnaire to 1,000 ordinary tenants in five municipalities; (d) process-oriented case studies of 32 LTAs between 1990 and 2006; and (e) case studies of four estates with alternative forms of local organisation.Between 1997 and 2005 the number of LTAs went down from 3,500 to 2,500. Those still existing take on the same roles as before and at almost the same level of activity. In the role as democratic community, tenants’ attendance at LTA general meetings is still relatively low, and the competition for seats on the board is almost non-existent. There is a slight female majority among LTA board members, whereas immigrants are poorly represented.In the role as grass-roots organisation, despite diminishing formal LTA influence within the tenant movement, LTAs and higher levels still co-operate regularly and in mutual respect. In the role as voice towards the landlord, most LTAs still have agreements on tenant participation, although the level of influence has gone down somewhat, in particular on economic issues. Finally, in the role as social organiser, LTAs still take great responsibility for leisure activities in their estates. All three roles as grass-roots organisation, voice and social organiser are considered to be important by LTAs. The role as the voice of the tenants in relation to the landlord is seen as the most important of the three, and the individual tenants responding to the questionnaire share this opinion. Most boards feel equally responsible to non-member residents as to members of the tenant union.Our case studies give some indications about the LTAs that have disappeared in the last decade. The 15 LTAs that were terminated since 1990 had lower levels of activity in all the four roles than the 17 still in existence. The case studies also indicate that the difference between development and decline can be explained in terms of institutionalisation: that associations grow successively less dependent on individual activists. In five extensive case studies we have identified how processes of institutionalisation and deinstitutionalisation arise and develop. These studies also illustrate that institutionalisation, cannot be taken for granted but is vulnerable to shifts in population and in relations to the landlord, including the sale of the estate.The alternative organisational units are far too few to replace the 1,000 LTA units that have disappeared. They sometimes engage individuals who have not been previously active, by means of openness to all tenants and informal modes of working. Still their activities have important similarities with those of LTAs, though many alternative units emphasize the role as social organiser more and, not surprisingly, the role as grass-roots organisation less than LTAs. Furthermore, without formal agreements, many of the alternative units have a weaker position to act as voice than LTAs. It is too early to say something definitive about the prospects of institutionalisation of the alternative forms. In most estates they still seem to be dependent on a few active tenants who put in a lot of effort in the activities.
|
|
| 8. |
- Bengtsson-Blücher, Daniel, et al.
(författare)
-
Influence of ppb levels of SO2 on the atmospheric corrosion of aluminum in the presence of NaCl
- 2005
-
Ingår i: Journal of the Electrochemical Society. - 1945-7111 .- 0013-4651. ; 152(10), s. B397-B404
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of part per billion (ppb) levels of SO2 on the atmospheric corrosion on Al (99.999%) was investigated in the laboratory at 22 degrees C. Exposure time was 20 and 672 h. The effect of SO2 concentration (46-1300 ppb), relative humidity (70- 99% RH), and the amount of NaCl applied prior to exposure (0- 250 mu g/cm(2)) was studied. In addition, the effect of O-3 and NO2 on the SO2 deposition rate was addressed. The samples were investigated by gravimetry, grazing incidence X-ray powder diffraction, ion chromatography, optical microscopy, and environmental scanning electron microscopy equipped with energy-dispersive X-ray fluorescence. SO2 accelerates the atmospheric corrosion of Al, forming corrosion product "islands" containing aluminum hydroxy sulfate. Combining NaCl and SO2 has a synergistic effect on the average corrosion rate. In contrast, the chloride-induced pitting of aluminum is significantly reduced by SO2. The corrosivity of SO2 is attributed to the acidification of the surface electrolyte that destabilizes the alumina passive film. The suppression of pitting corrosion by SO2 is attributed to the formation of aluminum hydroxy sulfates that are less soluble than the corresponding chlorides and slows down pit propagation. At relative humidities above 70% RH, there is a measurable steady-state deposition of SO2 that corresponds to the rate of formation of sulfate. The SO2 deposition rate is not limited by the oxidation of (IV)-valent sulfur on the surface. SO2 deposition is enhanced by sodium chloride because the corrosion reactions in the NaCl(aq) electrolyte result in high pH in the cathodic regions and the formation of aluminum hydroxide. Ozone in the ppb range has only transient effects on the SO2 deposition rate, whereas ppb levels of NO2 had no effect at (c) 2005 The Electrochemical Society.
|
|
| 9. |
- Bengtsson, Charlotte, et al.
(författare)
-
Conformity assessment for machine graded timber by using output control
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the Nordic countries machine strength grading of structural timber is becoming increasingly important. A new standard, EN 14081, which allows CE-marking of strength graded structural timber was recently accepted. This standard allows both machine control and output control as methods for controlling the graded timber. Machine control is most commonly used in Europe. The project reported here deals with output control. This method is commonly used in for example USA. Theoretical studies carried out within this project show that applying output control gives higher yield, especially in high strength classes. A document describing the implementation of the output control procedure is written and given in Appendix 1 of this report.
|
|
| 10. |
|
|
