| 1. |
- Frisk, U., et al.
(författare)
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The Odin satellite - I. Radiometer design and test
- 2003
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 402:3, s. L27-L34
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Tidskriftsartikel (refereegranskat)abstract
- The Sub-millimetre and Millimetre Radiometer (SMR) is the main instrument on the Swedish, Canadian, Finnish and French spacecraft Odin. It consists of a 1.1 metre diameter telescope with four tuneable heterodyne receivers covering the ranges 486-504 GHz and 541-581 GHz, and one fixed at 118.75 GHz together with backends that provide spectral resolution from 150 kHz to 1 MHz. This Letter describes the Odin radiometer, its operation and performance with the data processing and calibration described in Paper II.
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| 2. |
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| 3. |
- Erkfeldt, Sara U, 1974, et al.
(författare)
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Alumina-supported In2O3, Ga2O3 and B2O3 catalysts for lean NOx reduction with dimethyl ether
- 2012
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Ingår i: Applied Catalysis B: Environmental. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 117, s. 369-383
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Tidskriftsartikel (refereegranskat)abstract
- Alumina-supported In2O3, Ga2O3 and B2O3 were investigated as catalysts for lean NOx reduction with DME as reducing agent and compared to pure Al2O3 and In2O3. The In2O3-promoted alumina catalysts showed the highest NOx conversion at low temperatures, although with a narrow temperature window. Pure In2O3, on the other hand, was inactive for NOx reduction with DME. The Ga2O3- and B2O3-promoted alumina catalysts gave the highest NOx conversion at higher temperatures, showed a temperature window similar to pure alumina, but were less sensitive to H2O inhibition. Possible reasons for these observations are discussed.
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| 4. |
- Erkfeldt, Sara U, 1974, et al.
(författare)
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Influence of the reducing agent for lean NOx reduction over Cu-ZSM-5
- 2011
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Ingår i: Applied Catalysis B: Environmental. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 102:3-4, s. 547-554
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Tidskriftsartikel (refereegranskat)abstract
- A range of ethers, alcohols and alkanes were compared as reducing agents for NOx over a Cu-ZSM-5 lean NOx catalyst. The nature of the reducing agent was found to determine the degree of NOx reduction. Methanol and DME were virtually inactive as reductants over this catalyst, while higher ethers and alcohols showed high NOx conversion. A detailed study was performed to investigate the differences. Among the studied variables, the chemical structure of the reductant was found to be especially important. Despite having a lower reducing capacity than DME, ethylene glycol was active for NOx reduction. It is concluded that a C-C bond in the reducing agent is required for lean NOx reduction over Cu-ZSM-5. The absence of this bond in DME and methanol explains their low activity for NOx reduction over this catalyst.
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| 5. |
- Erkfeldt, Sara U, 1974, et al.
(författare)
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Lean NOx Reduction with Various Bio-Diesels as Reducing Agents
- 2011
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Ingår i: Topics in Catalysis. - : Springer Science and Business Media LLC. - 1572-9028 .- 1022-5528. ; 54:16-18, s. 1219-1223
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Tidskriftsartikel (refereegranskat)abstract
- Commercial Cu-ZSM-5- and Ag/Al2O3-based lean NOx catalysts were evaluated in a synthetic exhaust gas bench with the fuels RME, B30, B15, Agrodiesel 15, GTL, NExBTL, and MK1 as reducing agents. The influence of reductant was larger for Ag/Al2O3, albeit moderate, whereas the Cu-zeolite showed the highest NOx conversion at lower temperature for all alternative fuels tested.
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| 6. |
- Petersson, Martin, 1972
(författare)
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Catalytic Emission Abatement and Gas Separation
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Air pollution is still today a major health problem. Emissions from mobile and stationary sources are regulated, but economical considerations limit the implementation of the most efficient abatement systems. To improve urban air quality, there is therefore a need to develop simple, durable and cost efficient emission control methods. In this thesis, methods to limit the emissions of ozone generating compounds, i.e. nitrogen oxides (NOx) and volatile organic compounds (VOCs), have been studied.The addition of ozone in order to initiate CO oxidation was studied over one Pt/alumina catalyst using flow reactor experiments and through mean-field simulations. Ozone reacted rapidly with CO already at room temperature. An Eley-Rideal mechanism between adsorbed CO and colliding ozone is suggested. The reduction in bulk CO concentration decreases the CO self-poisoning and consequently cause an earlier catalyst light-off.The addition of SO2 has been shown to promote the total oxidation of propane, ethanol and ethyl acetate over Pt/alumina catalysts. The dominating reason for the promoting effect is associated with the formation of a sulfur species at the Pt/alumina interface. The interface species desorbed at 670-720 K, and the promotion was therefore lost. At higher temperatures, residual promotion or deactivation was found depending on the sample initial dispersion.Continuous lean NOx reduction over three physical mixtures of zeolites was investigated. When propene was used as the reducing agent, the reduction efficiency was determined purely by the small pre zeolite, while both zeolites influenced the results when isooctane was used. The efficiency was in both cases dependent on the selectivity for the NO2 reduction to N2 compared to NO.The use of a CO2 selective zeolite membrane in the shift reactor has the potential to improve the H2 yield for a diesel reformer in a fuel cell APU system. The selective adsorption of CO2 from a gas mixture of CO, CO2 and H2 was studied experimentally and through molecular simulations. CO2 adsorption was favored under all conditions, but the selectivity increased at low temperature and high pressure.
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| 7. |
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| 8. |
- Petersson, Martin, 1972, et al.
(författare)
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Ozone promoted carbon monoxide oxidation on platinum/gamma-alumina catalyst
- 2006
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Ingår i: Journal of Catalysis. - : Elsevier BV. - 0021-9517 .- 1090-2694. ; 238:2, s. 321-329
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Tidskriftsartikel (refereegranskat)abstract
- CO oxidation with oxygen and ozone-oxygen mixtures was studied over a platinum/alumina monolith catalyst. Temperature ramp experiments were combined with mean-field Simulations to Study the reaction mechanisms. In the absence of ozone, a slow CO oxidation reaction was observed at low temperatures. The rate of this slow reaction was proportional to the square root of the oxygen pressure and independent of the CO concentration. At higher temperatures, the three-step Langmuir-Hinshelwood reaction mechanism dominated the CO oxidations. When some of the oxygen was exchanged for ozone, rapid oxidation of CO by ozone was observed. The suggested explanation was an Eley-Rideal mechanism, in which colliding ozone reacts with adsorbed CO oil the platinum surface. When this additional reaction step was included in the model, the Simulation results indicated a reduction in the bulk CO pressure. The experimentally observed ozone promotion of CO oxidation was thus attributed to a decrease in CO Surface self-poisoning.
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| 9. |
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| 10. |
- Skoglundh, Magnus, 1965, et al.
(författare)
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SO2 promoted oxidation of ethyl acetate, ethanol and propane
- 2001
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Ingår i: Applied Catalysis B: Environmental. - 0926-3373 .- 1873-3883. ; 30:3-4, s. 315-328
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Tidskriftsartikel (refereegranskat)abstract
- The effect of SO2 addition on the oxidation of ethyl acetate, ethanol, propane and propene, over Pt/gamma -Al2O3 and Pt/SiO2 has been investigated. The reactants (300-800 vol, ppm) were mixed with air and led through the catalyst bed. The conversions below and above light-off were recorded both in the absence and in the presence of 1-100 vol. ppm SO2. For the alumina-supported catalyst, the conversion of ethyl acetate, ethanol and propane was promoted by the addition of SO2, while the conversion of propene was inhibited. The effect of SO2 was reversible, i.e. the conversion of the reactants returned towards the initial values when SO2 was turned off. However, this recovery was quite slow. The oxidation of propane was inhibited by water, both in absence and presence of SO2. For the silica-supported catalyst no significant effect of SO2 could be observed on the conversion of ethyl acetate, ethanol or propane, whereas the conversion of propene was inhibited by the presence of SO2. In situ FTIR measurements revealed the presence of surface sulphates on the Pt/gamma -Al2O3 catalyst with and after SO2 addition. It is proposed that these sulphate groups enhance the oxidation of propane, ethyl acetate and ethanol by creating additional reaction pathways to Pt on the surface of the Pt/gamma -Al2O3 catalyst.
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| 11. |
- Skoglundh, Magnus, 1965, et al.
(författare)
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SO2 promoted oxidation of hydrocarbons
- 2001
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Ingår i: 5th European Congress on Catalysis, Limerick, Ireland, September 2-7, 2001.
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Konferensbidrag (refereegranskat)
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