| 1. |
- Eckerberg, Katarina, et al.
(författare)
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Varför brister politikerna när det gäller miljömålen?
- 2012
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Ingår i: Dagens Nyheter. - 1101-2447.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Vad ska vi svara? Politikernas ambitiösa miljömål uppfylls sällan eller aldrig. När våra elever frågar oss varför blir vi ofta svaret skyldiga. Om politikerna inte vill att väljarna ska dra slutsatsen att de har misslyckats, måste de ange en realistisk väg att nå de uppsatta målen. Det skulle väcka respekt, skriver ledande forskare och samhällsplanerare.
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| 2. |
- Anselm, Jonas, et al.
(författare)
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Bannlys alla politiska beslut som ger mer klimatutsläpp
- 2014
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Ingår i: Dagens Nyheter.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Torftig valdebatt. Dagspolitiken klarar inte att hantera ödesfrågan om klimatet, vilket oroar oss. Vi föreslår därför ett ”utsläppsmoratorium”: inga beslut får tas som ökar utsläppen av växthusgaser. Principen måste kopplas till mål om exempelvis förnybar energi och grön infrastruktur, skriver 23 forskare och debattörer.
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| 3. |
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| 4. |
- Fatima, Nowshir, et al.
(författare)
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Adsorption of ATF additives on wet clutch friction interfaces under water contaminated lubricant conditions
- 2014
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Konferensbidrag (refereegranskat)abstract
- Stable friction and positive slope of friction-speed is the typical criterion for a good clutch performance. Lubricated friction interfaces used for wet clutches produces different friction behavior depending on the lubricant conditions. Usually the lubricant conditions vary for different automatic transmission fluid (ATF) formulations implying e.g. water contamination and these conditions might influence the deterioration of the clutch plates. The aim of this paper is to verify additive adsorption on friction interfaces and ageing of the friction material in wet clutch system for a water contaminated commercial ATF (DEXRON® VI). Standard clutch plates are employed in an automated wet clutch test rig to evaluate the friction characteristics of the tested lubricant. For controlled test conditions (speed, contact pressure, oil temperature) and specific number of test cycles, the mean friction coefficient and the friction vs. speed relations are monitored during sliding test. The resultant tribofilms on the tested friction interface surfaces are characterized by means of Scanning Electron Microscopy-Energy Dispersive X-ray spectroscopy (SEM- EDS), Attenuated Total Reflectance -Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS analysis). The spectroscopic techniques were used to analyse adsorbed additives on friction interfaces and made it possible to correlate measured data to the specific friction behavior obtained after water contamination of the ATF.
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| 5. |
- Fatima, Nowshir, et al.
(författare)
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Degradation Mechanism of Automatic Transmission Fluid by Water as a Contaminant
- 2015
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Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology. - : SAGE Publications. - 1350-6501 .- 2041-305X. ; 229:1, s. 74-85
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Tidskriftsartikel (refereegranskat)abstract
- The degradation mechanism of water contaminated Automatic Transmission Fluids (ATF) was experimentally investigated. Water contaminated ATF was tribotested in a full-scale wet clutch test rig to monitor the friction durability during clutch ageing, and was also statically aged in oven to evaluate the interaction of ATF with water. The bulk properties and chemical nature of the ATF were analysed using viscosity measurements, Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). It was shown that water presence in the ATF can increase the mean friction coefficient over a short time period, though in the long term perspective there is a higher loss of mean friction. Phase separation of the water-in-oil emulsion by centrifugation at 20000 rpm made it possible to examine the water phase using infrared 2spectroscopy. The spectroscopic analysis revealed the hydrophilic nature of certain ATF constituents, although the impact of water on the bulk properties like lubricant viscosity and thermal stability was insignificant. The analysis of the tribotests showed that the friction increase for water contamination was a short-term effect and likely due to the interaction between polar surface active additives and water. Even though no significant change has been found for thermal degradation or in bulk properties of the lubricant, the initially changed action of the water soluble additives and generation of high friction resulted in a total deterioration of the clutch performance during long term use.
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| 6. |
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| 7. |
- Fatima, Nowshir, et al.
(författare)
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Influence of water on the tribological properties of zinc dialkyl-dithiophosphate and over-based calcium sulfonate additives in wet clutch contacts
- 2015
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 87, s. 113-120
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Tidskriftsartikel (refereegranskat)abstract
- Usually the wet clutch lubricant properties vary with different formulations of base oil types and additives. The aim of this paper was to evaluate the effect of water on the performance of additives in ATF. Simplified lubricants, ZDDP and over-based Ca-sulfonates detergent additives in an API Group I mineral base oil, were employed to compare with the commercial fully-formulated automatic transmission fluid (DEXRON®VI) during water-contamination. A full-scale wet clutch test rig was used to evaluate the frictional response due to water contamination of the lubricants. Fourier Transform Infrared Spectroscopy was utilized to evaluate the variation in the solubility of these polar organic additives in the water phase and Karl-Fischer titration was utilized to evaluate the post-test water content for different formulations.
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| 8. |
- Fatima, Nowshir, et al.
(författare)
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Surface chemistry of wet clutch influenced by water contamination in automatic transmission fluids
- 2016
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 96, s. 395-401
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Tidskriftsartikel (refereegranskat)abstract
- Lubricated friction interfaces used for wet clutches produces different friction behaviour depending on the lubricant conditions. Usually the lubricant conditions vary for water contamination in automatic transmission fluid (ATF). The presence of water retards the ATF performance by increasing the friction and can influence the deterioration of the clutch plates. Water as a polar contaminant can change the absorbability of the surface active additives, which might cause the characteristic friction behaviour. The aim of this paper is to verify the surface chemistry of tribotested standard friction interfaces lubricated with water contaminated commercial ATF (DEXRON® VI). The evidences of the influence of water on ATF performances were shown by surface analyses
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| 9. |
- Fredriksson, Andreas, et al.
(författare)
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Comparison between in situ total internal reflection vibrational spectroscopy of an adsorbed collector and spectra calculated by ab initio density functional theory methods
- 2007
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 111:26, s. 9299-9304
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Tidskriftsartikel (refereegranskat)abstract
- In this investigation, adsorbed heptyl xanthate on a Ge(111) surface was studied, as well as the free heptyl xanthate molecule, by means of first-principle density functional theory calculations. The modeled results were compared with the in situ total internal reflection vibrational spectroscopy spectra of heptyl xanthate adsorbed on a germanium internal reflection element and the transmission infrared spectrum of a heptyl xanthate ion in aqueous solution. The assignments of the vibrational frequencies were done for the adsorbed xanthate. The region between 1150 and 1000 cm(-1) seems suitable for discussing differences between an adsorbed xanthate and its corresponding ion. The modeled spectra for both the adsorbed xanthate and the xanthate ion are in good agreement with the experimentally retrieved spectra. This investigation shows the strength of using DFT calculations in the interpretation of absorption bands from molecules adsorbed at surfaces in situ.
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| 10. |
- Grahn, Oskar, et al.
(författare)
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Peritoneal infection after colorectal cancer surgery induces substantial alterations in postoperative protein levels : an exploratory study
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: Peritoneal infection, due to anastomotic leakage, after resection for colorectal cancer have been shown to associate with increased cancer recurrence and mortality, as well as cardiovascsular morbidity. Alterations in circulating protein levels could help shed light on the underlying mechanisms, prompting this exploratory study of 64 patients operated for colorectal cancer with anastomosis.Methods: Thirty-two cases who suffered a postoperative peritoneal infection were matched with 32 controls who had a complication-free postoperative stay. Proteins in serum samples at their first postoperative visit and at one year after surgery were analysed using proximity extension assays and enzyme-linked immunosorbent assays. Multivariate projection methods, adjusted for multiple testing, were used to compare levels between groups, and enrichment and network analyses were performed.Results: Seventy-seven proteins, out of 270 tested, were differentially expressed at a median sampling time of 41 days after surgery. Many of the differentially expressed top hub proteins have known involvement in cancer progression, survival, invasiveness and metastasis. Over-represented pathways were related to cardiomyopathy, cell-adhesion, extracellular matrix, phosphatidylinositol-3-kinase/Akt (PI3K/Akt) and transforming growth factor beta (TGF-β) signaling.Conclusion: These affected proteins and pathways could provide clues as to why these patients might suffer increased cancer recurrence, mortality and cardiovascular morbidity.
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