| 1. |
- Sanati, Negin, et al.
(författare)
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Growing interest in use of geographic information systems in health and healthcare research: a review of PubMed from 2003 to 2011.
- 2013
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Ingår i: JRSM short reports. - : SAGE Publications. - 2042-5333. ; 4:6
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in Undetermined There has been an increasing interest in applying GIS into health and healthcare research in recent years.4,5 However, this increasing interest has not yet been gauged. In order to address this, the current study was performed to examine the crude number and the annual rate of papers with ‘Geographic Information Systems’ among their MeSH Terms in PubMed (a free database which is maintained by US National Library of Medicine).
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| 2. |
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| 3. |
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| 4. |
- 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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| 5. |
- 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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| 6. |
- Andersson, Arne, et al.
(författare)
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Structure-Activity Relationships in the Oxidation of Alkylaromatics over Metal Oxides
- 1991
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Ingår i: Studies in Surface Science and Catalysis. - 0167-2991. ; 67, s. 43-55
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Tidskriftsartikel (refereegranskat)abstract
- In order to accomplish oxidation of alkylaromatic compounds, both cations, which serve as adsorption centers, and oxygen species of suitable bond strength are needed. When compared to partial oxidation, relatively weakly bonded oxygen species are involved in combustion. On the basis of these criteria, using a simple model of the active ensemble, a relationship between reaction rate and bond strength is derived for partial and total oxidation. Its applicability is demonstrated using data for the oxidation of toluene over a large number of binary metal oxides. Some characteristic features following from the model are discussed, considering catalytic results on the structure sensitivity of oxidation and ammoxidation reactions over crystalline V,O and MOO,. Furthermore, kinetic results on the oxidation of toluene to benzaldehyde and carbon oxides in presence of ammonia, which serves as an electron donor to the catalyst surface, demonstrate that the oxygen species taking part in partial oxidation and combustion are nucleophilic and electrophilic in character, respectively.
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| 7. |
- 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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| 8. |
- Arnby, Karl, 1974, et al.
(författare)
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Characterization of Pt/γ-Al2O3 catalysts deactivated by hexamethyldisiloxane
- 2004
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Ingår i: Applied Catalysis B: Environmental. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 54:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The deactivation of alumina supported platinum and iron catalysts by hexamethyldisiloxane (HMDS) exposure has been investigated. Three catalysts (Pt/Al2O3, Fe/Al2O3 and Fe/Pt/Al2O3) were prepared and the influence of short- and long-term deactivation on the activity for oxidation of ethyl acetate was studied. The catalysts were characterized using BET, ICP-AES, XPS, SEM and CO chemisorption. The deactivation was found to proceed by deposition of silicon-species in form of silicate (SixOy) that block the active sites on the surface of the catalysts. The silicon seems to rather attach to platinum and iron sites than to the alumina surface. The Pt/Al2O3 catalyst was moderately deactivated by HMDS even though the silicate was blocking almost the entire platinum surface. Adding iron to the catalyst increased the tolerance towards HMDS as fewer Pt sites were blocked for the Fe/Pt/Al2O3 sample. The deactivation of the two platinum containing samples was reversible since the silicate could partly be removed from the Pt sites by regeneration whereby most of the activity was restored. However, for the Fe/Al2O3 sample the deactivation was more severe and irreversible.
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| 9. |
- Augustsson, Ola
(creator_code:cre_t)
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A catalyst for catalytic oxidation of hydrocarbons
- 2004
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- A catalyst having resistance towards Si and/or P deactivation in catalytic oxidation of organic hydrocarbons is disclosed. The catalyst comprises a catalytically inert support, a catalytically active layer of metallic Pt and/or Pd and deposited on said catalytically active layer at least one oxide ...
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| 10. |
- Bagherpour, Mohammad Bagher, et al.
(författare)
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Effects of irrigation and water content of packings on alpha-pinene vapours biofilteration performance
- 2005
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Ingår i: Biochemical engineering journal. - : Elsevier. - 1369-703X .- 1873-295X. ; 24:3, s. 185-193
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Tidskriftsartikel (refereegranskat)abstract
- The main objective of this investigation is to determine the effect of different physical parameters on the performance of biofilters, treating hydrophobic compounds. In this respect, the effects of irrigation and water content of packings on the removal efficiency of bed in different pollutant loading rates, and gas phase flow rates, is studied. Alpha-pinene, which is produced from variety of industrial wood products, pulp and paper industries, and fragrance production units, has been selected as a model compound. Since the effectiveness of biofiltration depends strongly upon water solubility of compounds, in the case of alpha-pinene (2.5 ppm, at 25 ◦C), the process of waste gas treatment is faced with difficulties. In this paper, it is shown that performance of biofilters, treating hydrophobic contaminants, declines due to irrigation. This reduction is detected by an increase in the outlet concentration from 11% up to 22.5%. Its magnitude depends on the gas velocity inside the biofilter and outlet concentration of the bed. The result indicated that pore blocking along the bed has less effect on the performance reduction than diffusion coefficient. Also the inhibitory effects of velocity on biodegradation are considerably higher than the effects of concentration. In addition, this compost-based biofilter shows noteworthy higher elimination capacities in comparison with previous studied biofiltration systems. In this study, a maximum elimination capacity of 227 gm−3 of packing h−1 is achieved by 95% of removal efficiency. The maximum concentration in the inlet gas was 650 mgm−3.
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