| 1. |
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- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Albertazzi, S, et al.
(författare)
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The technical feasibility of biomass gasification for hydrogen production
- 2005
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Ingår i: Catalysis Today. - : Elsevier BV. - 0920-5861 .- 1873-4308. ; 106:1-4, s. 297-300
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Tidskriftsartikel (refereegranskat)abstract
- Biomass gasification for energy or hydrogen production is a field in continuous evolution, due to the fact that biomass is a renewable and CO2 neutral source. The ability to produce biomass-derived vehicle fuel on a large scale will help to reduce greenhouse gas and pollution, increase the security of European energy supplies, and enhance the use of renewable energy. The Varnamo, Biomass Gassification Centre in Sweden is a unique plant and an important site for the development of innovative technologies for biomass transformation. At the moment, the Varnamo plant is the heart of the CHRISGAS European project, that aims to convert the produced gas for further upgrading to liquid fuels as dimethyl ether (DME), methanol or Fischer-Tropsch (F-T) derived diesel. The present work is an attempt to highlight the conditions for the reforming unit and the problems related to working with streams having high contents of sulphur and alkali metals.
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| 3. |
- Andersson, Arne, et al.
(författare)
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Direct Propane Ammoxidation to Acrylonitrile: Kinetics and Nature of the Active Phase
- 1993
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Ingår i: New Frontiers in Catalysis (Studies in Surface Science and Catalysis ). - 0167-2991. ; 75, s. 691-705
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Konferensbidrag (refereegranskat)abstract
- The kinetics of the direct synthesis of acrylonitrile from propane on V-Sb-Al-(W) mixed oxides indicate that acrylonitrile (ACN) forms by two parallel pathways, one directly from propane and the second, which is the prevalent path, through the intermediate formation of propylene (C3=). The limiting factor in the formation of ACN is the relative slowness of the step of allylic oxidation to ACN of the intermediate C3=, and the higher rate of C3= oxidation to carbon oxides as compared to that of ACN to COx. The step of C3= oxidation to ACN is controlled by the surface availability of NH3 which, in turn, depends considerably on the side reaction of NH3 oxidation to N2. The catalytic behavior of different modified V-Sb-(Al)-O systems and their characterization by X-ray diffraction analysis and Raman, Infrared and X-ray Photoelectron spectroscopies indicate that i) a reduction of both V and Sb occurs during the catalytic reaction, ii) the presence of vanadium not stabilized in the rutile-like phase is responsible for the side reaction of NH3 oxidation and lowering of the selectivity, iii) alumina reacts with antimony forming an AlSbO4 rutile phase which could be epitaxially intergrown or in solid solution with the VSbO4/Sb2O4 system, which, in turn, limits the presence of not stabilized (unselective) vanadium species, and iv) antimony oxide supported on alumina is also selective in propane ammoxidation, but forming acetonitrile as the main product. The doping with vanadium of this sample increases slightly the activity, but especially gives rise to the formation of acrylonitrile instead of acetonitrile.
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| 4. |
- Andersson, Arne, et al.
(författare)
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Surface Characterization and Reactivity in Ammoxidation Reactions of Vanadium Antimonate Catalysts
- 1994
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Ingår i: Applied Catalysis A: General. - 0926-860X. ; 113:1, s. 43-57
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Tidskriftsartikel (refereegranskat)abstract
- Unsupported vanadium antimonate catalysts with Sb/V ratios of 1 and 5 and samples with the latter ratio supported on alumina were studied in toluene and propane ammoxidation to benzonitrile and acrylonitrile, respectively, and were characterized by X-ray photoelectron spectroscopy (XPS) analysis before and after catalytic tests. Activity data for toluene ammoxidation suggest that excess antimony with respect to the stoichiometric amount required for forming the VSbO4 rutile phase affects the dispersion of the latter phase giving smaller particles. Vanadium sites are involved both in the activation of toluene and in the insertion of nitrogen in this reaction, whereas antimony does not play a specific role in the reaction mechanism. In propane ammoxidation, on the other hand, due to a higher reaction temperature with respect to toluene (500°C vs. 370°C), free vanadia on the surface of the catalyst has a negative influence on the selectivity because it promotes the conversion of ammonia to nitrogen, decreasing the surface nitrogenous species required for the selective formation of acrylonitrile. Excess antimony is thus necessary for completing the reaction between antimony and vanadium oxides, but antimony also participates in the reaction mechanism. In propane ammoxidation, in fact, XPS data show that both vanadium and antimony sites are reduced. Tentatively, vanadium sites are involved in the activation of propane, while antimony sites insert nitrogen. The differences between the toluene and propane ammoxidation mechanisms are interpreted to be primarily related to the different reaction temperatures.
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| 5. |
- Chakera, Annette H., et al.
(författare)
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EANM-EORTC general recommendations for sentinel node diagnostics in melanoma
- 2009
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 36:10, s. 1713-1742
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Forskningsöversikt (refereegranskat)abstract
- The accurate diagnosis of a sentinel node in melanoma includes a sequence of procedures from different medical specialities (nuclear medicine, surgery, oncology, and pathology). The items covered are presented in 11 sections and a reference list: (1) definition of a sentinel node, (2) clinical indications, (3) radiopharmaceuticals and activity injected, (4) dosimetry, (5) injection technique, (6) image acquisition and interpretation, (7) report and display, ( 8) use of dye, ( 9) gamma probe detection, (10) surgical techniques in sentinel node biopsy, and (11) pathological evaluation of melanoma-draining sentinel lymph nodes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "general consensus" and similar expressions. The recommendations are designed to assist in the practice of referral to, performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for good-quality evaluation of possible spread to the lymphatic system in intermediate-to-high risk melanoma without clinical signs of dissemination.
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| 6. |
- Sanati, Mehri, et al.
(författare)
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Kinetic Study on Propane Ammoxidation to Acrylonitrile over V-Sb-O/TiO2(B)
- 1998
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Ingår i: Catalysis Today. - 0920-5861. ; 42:3, s. 325-332
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Tidskriftsartikel (refereegranskat)abstract
- Kinetic study on propane ammoxidation to acrylonitrile over V–Sb–O/TiO2(B) was undertaken by a strict mathematical analysis of experimental rate dependencies on reactant pressure in order to obtain expression describing completely the data.
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