| 11. |
- Bergsten, Eva L., et al.
(författare)
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Skadefria cargo- och flygplanslastare - slutrapport
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- SammanfattningArbetsmiljöprojektet Skadefria cargo- och flygplanslastare har utförts på uppdrag av Svenska Transportarbetareförbundet och Svenska Flygbranschen med syfte att kartlägga flygplanslastarnas arbetsförhållanden och att komma med förslag på förbättringsåtgärder för att minska belastningsrelaterade skador och sjukdomar i branschen.Projektledningsgruppen har bestått av fem personer: Eva Bergsten, ergonom, anställd av projektet; Erik Alphonse, projektledare, TYA; Reidar Pettersson, arbetsmiljökonsult, Arbetsmiljölotsen; Svend Erik Mathiassen, professor, Centrum för belastningsskadeforskning vid Högskolan i Gävle; och Dan Holmberg, regionalt skyddsombud, Transportarbetareförbundet.Projektet som omfattade 14 bolag (11 handling, 3 cargo) på sex flygplatser (Arlanda, Malmö, Göteborg, Växjö, Skavsta och Arvidsjaur) startades våren 2010 och avslutades våren 2012, efter en inledande pilotstudie våren 2010 som finansierades av TYA. Inom projektet har 1 039 enkäter distribuerats med frågor om psykosociala arbetsförhållanden, upplevd arbetsbelastning, trötthet och besvär. Svarsfrekvensen var 72 procent. Heldagsmätningar av arbetsställningar för rygg och armar har genomförts på 5-6 lastare per flygplats samtidigt som lastarna filmats och fyllt i dagböcker. Fokusgrupper har intervjuats och data om till exempel sjukskrivningar och olyckstillbud har samlats in från företagen.Parallellt med den vetenskapliga delen har projektet haft en praktisk del med fyra arbetsgrupper bestående av representanter från både arbetsgivar- och arbetstagarsidan. Grupperna har träffats två gånger per termin och jobbat inom områdena: I) fysisk belastning och arbetsskadestatistik, II) arbetsorganisation, schemaläggning och psykosocial arbetsmiljö, III) hjälpmedel och metoder samt IV) utbildning och utveckling.Våra resultat visar att besvärsfrekvenserna i muskler och leder är relativt höga. Det finns arbetsmoment i lastaryrket som är ogynnsamma och som ökar risken för besvär, framför allt i axlar/skuldra, rygg och handleder/händer. De arbetsuppgifter som en lastare har skiljer sig inte så mycket åt mellan de olika flygplatserna, men det finns betydande skillnader i hur ofta och hur länge uppgifterna förekommer. Vid vissa flygplatser är således flyglastararbetet mera varierat än vid andra, vilket förmodligen har en betydelse för risken att utveckla besvär.Överlag fanns det hjälpmedel för de mest belastande arbetsmomenten, men också brister i hur dessa används.Inom den psykosociala arbetsmiljön visade projektet på ett behov av att förbättra ledarskapet och lastarnas inflytande i planering och genomförande av det egna arbetet. Bättre feedback i form av stöd och uppmuntran från ledare efterfrågades också.Arbetsgrupperna, som löpande delgavs resultaten från den vetenskapliga kartläggningen, utvecklade i enlighet med projektets målsättning ett antal åtgärdsförslag, med stöd i kartläggningen. Förslagen, som presenteras i denna rapport, är av generell natur. Flera av förslagen omfattar ett flertal möjliga delåtgärder och initiativ, som naturligtvis måste anpassas för och prioriteras av det enskilda bolaget utifrån dess egna förutsättningar. Mot bakgrund av våra projektresultat vill vi dock generellt rekommendera samtliga bolag att lägga en viss prioritet på de psykosociala arbetsförhållandena i sitt förbättringsarbete. Det fanns även uppenbara möjligheter att förbättra den fysiska belastningsprofilen, särskilt genom att bredda arbetsinnehållet på vissa flygplatser, och genom en mera effektiv användning av tekniska hjälpmedel. Samtidigt är det viktigt att framhålla att lastaryrket även har många goda sidor i form av ett rörligt och spännande arbete med ett bra socialt klimat.Vår bedömning är att de förslag till förändringar i arbetsmiljö och arbetsvillkor som föreslås i denna rapport skulle leda till en bättre arbetsmiljö men sannolikt också kunna påverka effektiviteten i arbetet i positiv riktning.Projektet Skadefria cargo- och flygplanlastare är föremål för en avhandling vilket betyder att vidare analyser av insamlade data kommer att ske. Resultaten kommer framöver att publiceras i vetenskapliga tidsskrifter.
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| 12. |
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| 13. |
- Castarède, Dimitri, et al.
(författare)
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Development and characterization of the Portable Ice Nucleation Chamber 2 (PINCii)
- 2023
-
Ingår i: Atmospheric Measurement Techniques. - 1867-1381. ; 16:16, s. 3881-3899
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Tidskriftsartikel (refereegranskat)abstract
- The Portable Ice Nucleation Chamber 2 (PINCii) is a newly developed continuous flow diffusion chamber (CFDC) for measuring ice nucleating particles (INPs). PINCii is a vertically oriented parallel-plate CFDC that has been engineered to improve upon the limitations of previous generations of CFDCs. This work presents a detailed description of the PINCii instrument and the upgrades that make it unique compared with other operational CFDCs. The PINCii design offers several possibilities for improved INP measurements. Notably, a specific icing procedure results in low background particle counts, which demonstrates the potential for PINCii to measure INPs at low concentrations ( < 10 L (-1)). High-spatial-resolution wall-temperature mapping enables the identification of temperature inhomogeneities on the chamber walls. This feature is used to introduce and discuss a new method for analyzing CFDC data based on the most extreme lamina conditions present within the chamber, which represent conditions most likely to trigger ice nucleation. A temperature gradient can be maintained throughout the evaporation section in addition to the main chamber, which enables PINCii to be used to study droplet activation processes or to extend ice crystal growth. A series of both liquid droplet activation and ice nucleation experiments were conducted at temperature and saturation conditions that span the spectrum of PINCii's operational conditions ( 50 <= temperature <= 15 degrees C and 100 <= relative humidity with respect to ice <= 160 %) to demonstrate the instrument's capabilities. In addition, typical sources of uncertainty in CFDCs, including particle background, particle loss, and variations in aerosol lamina temperature and relative humidity, are quantified and discussed for PINCii.
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| 14. |
- Collaboration, The PANDA, et al.
(författare)
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Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
- 2016
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Ingår i: European Physical Journal A. - : Springer Publishing Company. - 1434-6001 .- 1434-601X. ; 52:10
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Tidskriftsartikel (refereegranskat)abstract
- Simulation results for future measurements of electromagnetic proton form factors at P ¯ ANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel p¯ p→ e+e- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e.p¯ p→ π+π-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.
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| 15. |
- Eriksson, Axel, et al.
(författare)
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Particulate PAH Emissions from Residential Biomass Combustion : Time-Resolved Analysis with Aerosol Mass Spectrometry
- 2014
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 48:12, s. 7143-7150
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Tidskriftsartikel (refereegranskat)abstract
- Time-resolved emissions of particulate polycyclic aromatic hydrocarbons (PAHs) and total organic particulate matter (OA) from a wood log stove and an adjusted pellet stove were investigated with high-resolution time-of-flight aerosol mass spectrometry (AMS). The highest OA emissions were found during the addition of log wood on glowing embers, that is, slow burning pyrolysis conditions. These emissions contained about 1% PAHs (of OA). The highest PAH emissions were found during fast burning under hot air starved combustion conditions, in both stoves. In the latter case, PAHs contributed up to 40% of OA, likely due to thermal degradation of other condensable species. The distribution of PAHs was also shifted toward larger molecules in these emissions. AMS signals attributed to PAHs were found at molecular weights up to 600 Da. The vacuum aerodynamic size distribution was found to be bimodal with a smaller mode (Dva ~ 200 nm) dominating under hot air starved combustion and a larger sized mode dominating under slow burning pyrolysis (Dva ~ 600 nm). Simultaneous reduction of PAHs, OA and total particulate matter from residential biomass combustion may prove to be a challenge for environmental legislation efforts as these classes of emissions are elevated at different combustion conditions.
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| 16. |
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| 17. |
- Glans, Erik, 1980-
(författare)
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Pension reforms and retirement behaviour
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of three self-contained essays. Essay 1. Knowledge about how elderly workers react to changes in pension benefits is important in guiding the design of social security systems. This essay contributes to this knowledge by examining the effect of changes in replacement rates on part-time retirement behaviour in Sweden. During the 1980s, older workers had the option of partial retirement with an income replacement rate of 65 percent. The replacement rate was lowered to 50 percent in 1981 and subsequently returned to 65 percent in 1987. Estimates using a linear probability model with register data from the LINDA database suggest that fewer men and women chose part-time retirement after the reduction in benefit levels in 1981. There was an approximate 4 percentage point drop in the partial retirement propensity among eligible 60 year-old men, and a 5.7 percent drop among women. This corresponds to proportional reductions in the retirement propensity by about 29 and 36 percent, respectively. The probability of part-time retirement increased among men by about 3.5 percentage points once benefit levels returned back in 1987, whereas the partial retirement probability of women remained largely unchanged. Essay 2. The Swedish pension reform 1999-2003 provides an opportunity to study whether and how important economic incentives are for the timing of retirement. The new pension system provides a much closer link between contributions and benefits than the former system. I study whether the reform has led to delayed retirement by examining the retirement patterns of elderly individuals in the Swedish labour force who were differentially affected by the reform. I use duration analysis with annual data from the LINDA database. Discrete time proportional hazard models are estimated. There is a clear downward trend in the retirement hazard, implying delayed retirement, among more recent cohorts. Most of the decline occurs among public sector employees. Essay 3. This essay estimates the effect of a change from a de- fined benefit pension system to a defined contribution pension system on retirement behaviour. This is done by examining the occupational pension reform for Swedish local government employees of 1998-2000. Both anticipatory and post reform behavioral response is studied. Time, age, and occupational category provide identification. Both difference-in-differences and triple differences are estimated using the discrete time proportional hazard model on a large representative sample of 60-64 year-olds in the labour market from 1996 to 2005. Estimates indicate that the retirement hazard increased by about 38 percent in anticipation of the reform, and subsequently dropped by about 60 percent. The post reform effect corresponds for an approximate additional average time in the labour force of about 6.5 months for the treated group in the 60-64 age span. This essay shows that changes in pension schemes that contribute relatively little to total individual pension wealth may have disproportionately large effects on retirement behavior if the schemes provides strong incentives for early retirement.
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| 18. |
- Hallgren, Christoffer, et al.
(författare)
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Classification and properties of non-idealized coastal wind profiles - an observational study
- 2022
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Ingår i: Wind Energy Science. - : Copernicus Publications. - 2366-7443 .- 2366-7451. ; 7:3, s. 1183-1207
-
Tidskriftsartikel (refereegranskat)abstract
- Non-idealized wind profiles frequently occur over the Baltic Sea and are important to take into consideration for offshore wind power, as they affect not only the power production but also the loads on the structure and the behavior of the wake behind the turbine. In this observational study, we classified non-idealized profiles as the following wind profiles having negative shear in at least one part of the lidar wind profile between 28 and 300 m: low-level jets (with a local wind maximum in the profile), profiles with a local minimum and negative profiles. Using observations spanning over 3 years, we show that these non-idealized profiles are common over the Baltic Sea in late spring and summer, with a peak of 40 % relative occurrence in May. Negative profiles (in the 28-300 m layer) mostly occurred during unstable conditions, in contrast to low-level jets that primarily occurred in stable stratification. There were indications that the strong shear zone of low-level jets could cause a relative suppression of the variance for large turbulent eddies compared to the peak of the velocity spectra, in the layer below the jet core. Swell conditions were found to be favorable for the occurrence of negative profiles and profiles with a local minimum, as the waves fed energy into the surface layer, resulting in an increase in the wind speed from below.
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| 19. |
- Herstad-Svärd, S., et al.
(författare)
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Ramprogram – Åtgärder för samtidig minimering av alkalirelaterade driftproblem, Etapp 2
- 2007
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Combustion of an increasing amount of biofuel and waste woods has resulted in certainenvironmental advantages, including decreased emissions of fossil CO2, SO2 andmetals. On the other hand, a number of chloride and alkali related operational problemshave occurred which are related to combustion of these fuels.Alkali related operational problems have been studied in a project consisting of twoparts. The overall scope has been to characterise the operational problems and to studymeasures to minimise them. The first part was reported in Värmeforsk report 997 wherethe results were summarised in a table of different measures. In part two, additionalmeasures have been included in the test plan and initial corrosion has been studiedlinked to the different measures. The tests have also in part two been carried out at the12 MW CFB boiler at Chalmers. The effect of the selected measures has beeninvestigated concerning both deposit formation and bed agglomeration, and at the sametime emissions and other operational conditions were characterised.The second part of the project has among other things focused on:• To investigate measures which decrease the content of alkali and chloride in thedeposits, and consequently decrease the risk for corrosion (by investigating theinitial corrosion). Focus was also on trying to explain favourable effects.• To investigate if it is possible to combine a rather low dosage of kaolin and injectionof ammonium sulphate. This was done in order to reduce both bed agglomerationand problems from deposits during combustion of fuels rich in chlorine.• To investigate if co-combustion with sewage sludge, de-inking sludge or peat withhigh ash content, could give similar advantages as conventional additives.• Investigate if ash from PFBC is possible to use as an alternative bed material.By comparing the different measures in part two, it could be concluded that cocombustionof sewage sludge gave the best overall effect. The judgement was based onthe effects concerning bed agglomeration, level of alkali chloride in the flue gas,deposits and initial corrosion. Simultaneous addition of kaolin and ammonia sulphatealso had a favourable impact both in the bed and on the alkali chlorides in the gas phase.Dosage of kaolin did not reduce the effect of injected ammonium sulphate. Cocombustionof peat could also be a very attractive alternative, but it is critical to select asuitable peat type. It is of special concern to avoid peat with a high content of calcium,since it can increase the level of alkali chlorides by reacting with available sulphur.Change of bed material to ash from PFBC can decrease problems with bedagglomeration, but there is a risk of increased deposit formation and corrosion. A boileroperated with high steam data should consequently combine the change of bed materialwith injection of ammonium sulphate or another source of sulphur.Co-combustion of de-inking sludge from pulp and paper production can reduceproblems with bed agglomeration. There is, however, an increased chance of corrosiondue to the high content of calcium. Injection of sulphates may improve the situationconcerning corrosion. The results also showed that low potassium chlorine content in the flue gas decreasesthe risk of corrosion. Increased amount of potassium chlorine content in the flue gaswill not necessary give a high amount of chlorine content in the deposits if there is sulphur in the system.Key words: agglomeration, deposits, corrosion, alkali, kaolin, ammonium sulphate,sludge
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| 20. |
- Höglund, Linda, 1974-, et al.
(författare)
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Energy level scheme of InAs/InxGa1-xAs/GaAs quantum-dots-in-a-well infrared photodetector structures
- 2010
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - Woodbury, NY : American Physical Society. - 1098-0121 .- 1550-235X. ; 82:3, s. 035314-
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Tidskriftsartikel (refereegranskat)abstract
- A thorough investigation of quantum-dots-in-a-well structures for infrared photodetector applications has been performed employing different experimental techniques. The electronic structure of self-assembled InAs quantum dots embedded in an In0.15Ga0.85As/GaAs quantum well (QW) was deduced from photoluminescence (PL) and PL excitation (PLE) spectroscopy. From polarization-dependent PL it was revealed that the quantum dots hold two electron energy levels and two heavy-hole levels. Tunnel capacitance spectroscopy confirmed an electron energy level separation of about 50 meV, and additionally, that the conduction-band ground state and excited state of the dots are twofold and fourfold degenerates, respectively. Intersubband photocurrent spectroscopy, combined with simultaneous interband pumping of the dots, revealed a dominant transition at 150 meV (8.5 mu m) between the ground state of the quantum dots and the excited state of the QW. Results from detailed full three-dimensional calculations of the electronic structure, including effects of composition intermixing and interdot interactions, confirm the experimentally unravelled energy level scheme of the dots and well.
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