| 1. |
- Andersson, AM, et al.
(författare)
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Temperature dependence of the passivation layer on graphite
- 1999
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Ingår i: JOURNAL OF POWER SOURCES. - : ELSEVIER SCIENCE SA. - 0378-7753. ; 82, s. 286-290
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The elevated temperature stability of the Solid Electrolyte Interface (SEI) formed on graphite during the first charge/discharge cycle has been investigated. This was done in order to determine its role in the high-temperature degradation process which oc
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| 2. |
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| 3. |
- de Leeuw, N.H., et al.
(författare)
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Modeling the competitive adsorption of water and methanoic acid on calcite and fluorite surfaces
- 1998
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 14:20, s. 5900-5906
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Tidskriftsartikel (refereegranskat)abstract
- Atomistic simulation techniques were used to investigate the interaction between the minerals calcite and fluorite with water and methanoic acid. The relative adsorption energies suggest that methanoic acid preferentially adsorbs onto fluorite surfaces, while adsorption of water is energetically preferred over methanoic acid on the calcite cleavage plane in agreement with experiment. The coverage and configuration of adsorbed methanoic acid on the surfaces depends largely on lattice spacing between the cations, and bridging between surface calcium atoms is highly favored. These findings have given an insight into interactions at the atomic level which indicate that modeling techniques should be capable of predicting adsorption behavior and designing collector molecules, which is of central importance to the mineral processing technique of flotation
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| 4. |
- Deo, N., et al.
(författare)
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Biodegradation of some organic reagents from mineral process effluents
- 1999
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Ingår i: Biohydrometallurgy and the Environment toward the Mining of the 21st century. - : Elsevier. - 0444501932 ; , s. 687-696
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Konferensbidrag (refereegranskat)abstract
- The utility of a soil microbe, namely Bacillus polymyxa, in the removal of organic reagents such as dodecylamine, ether diamine, isopropyl xanthate and sodium oleate from aqueous solutions is demonstrated. Time-bound removal of the above organic reagents from an alkaline solution was investigated under different experimental conditions during bacterial growth and in the presence of metabolites by frequent monitoring of residual concentrations as a function of time, reagent concentration and cell density. The stages and mechanisms in the biodegradation process were monitored through UV-visible and FTIR spectroscopy. Surface chemistry of the bacterial cells as well as the biosorption tendency for various organics were also established through electrokinetic and adsorption density measurements. Both the cationic amines were found to be biosorbed followed by their degradation through bacterial metabolism. The presence of the organic reagents promoted bacterial growth through effective bacterial utilization of nitrogen and carbon from the organics. Under optimal conditions, complete degradation and bioremoval of all the organics could be achieved
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| 5. |
- Natarajan, E, et al.
(författare)
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Experimental determination of bed agglomeration tendencies of some common agricultural residues in fluidized bed combustion and gasification
- 1998
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Ingår i: Biomass and Bioenergy. - 0961-9534 .- 1873-2909. ; 15:2, s. 163-169
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Tidskriftsartikel (refereegranskat)abstract
- Ever increasing energy demand and the polluting nature of existing fossil fuel energy sources demonstrate the need for other non-polluting and renewable sources of energy. The agricultural residues available in abundance in many countries can be used for power generation. The fluidized bed technology seems to be suitable for converting a wide range of agricultural residues into energy, due to its inherent advantages of fuel flexibility, low operating temperature and isothermal operating condition. The major ash-related problem encountered in fluidized beds is bed agglomeration which, in the worst case, may result in total defluidization and unscheduled downtime. The initial agglomeration temperature for some common tropical agricultural residues were experimentally determined by using a newly developed method based on the controlled fluidized bed agglomeration test. The agricultural residues chosen for the study were rice husk, bagasse, cane trash and olive flesh. The results showed that the initial agglomeration temperatures were less than the initial deformation temperature predicted by the ASTM standard ash fusion tests for all fuels considered. The initial agglomeration temperatures of rice husk and bagasse were more than 1000°C. The agglomeration of cane trash and olive flesh was encountered at relatively low temperatures and their initial agglomeration temperatures in gasification were lower than those in combustion with both bed materials. The use of lime as bed material instead of quartz improved the agglomeration temperature of cane trash and olive flesh in combustion and decreased the same in gasification. The results indicate that rice husk and bagasse can be used in the fluidized bed for energy generation since their agglomeration temperatures are sufficiently high.
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| 6. |
- Natarajan, E., et al.
(författare)
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Overview of combustion and gasification of rice husk in fluidized bed reactors
- 1998
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Ingår i: Biomass and Bioenergy. - 0961-9534 .- 1873-2909. ; 14, s. 533-546
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Tidskriftsartikel (refereegranskat)abstract
- Rice is cultivated in more than 75 countries in the world. The rice husk is the outer cover of the rice and on average it accounts for 20% of the paddy produced, on weight basis. The worldwide annual husk output is about 80 million tonnes with an annual energy potential of 1.2 x 10 9 GJ corresponding to a heating value of 15 MJ/kg. India alone generates about 22 million tonnes of rice husk per year. If an efficient method is available, the husk can be converted to a useful form of energy to meet the thermal and mechanical energy requirements of the rice mills themselves. This paper provides an overview of previous works on combustion and gasification of rice husk in atmospheric bubbling fluidized bed reactors and summarizes the state of the art knowledge. As the high ash content, low bulk density, poor flow characteristics and low ash melting point makes the other types of reactors like grate furnaces and downdraft gasifiers either inefficient or unsuitable for rice husk conversion to energy, the fluidized bed reactor seems to be the promising choice. The overview shows that the reported results are from only small bench or lab scale units. Although a combustion efficiency of about 800 can normally be attained; the reported values in the literature, which are more than 95%, seem to be in higher order. Combustion intensity of about 530 kg/h/m 2 is reported. It is also technically feasible to gasify rice husk in a fluidized bed reactor to yield combustible producer gas, even with sufficient heating value for application in internal combustion engines. A combustible gas with heating value of 4-6 MJ/Nm 3 at a rate of 2.8-4.6 MW(th)/m 2 seems to be possible. Only very little information is available on the pollutant emissions in combustion and tar emissions from gasification. The major conclusion is that the results reported in the literature are limited and vary widely, emphasizing the need for further research to establish suitable and optimum operating conditions for commercial implementations.The combustion and gasification of rice husks in atmospheric bubbling fluidized bed reactors are studied. The rice husks are gasified in the bed reactor to yield combustible producer gas, even with sufficient heating value for application in internal combustion engines. A combustible gas with heating value of 4-6 MJ/Nm 3 at a rate of 2.8-4.6 MW th/m 2 is possible.
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| 7. |
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| 8. |
- Whitehead, AH, et al.
(författare)
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In situ X-ray diffraction studies of a graphite-based Li-ion battery negative electrode
- 1996
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Ingår i: JOURNAL OF POWER SOURCES. - 0378-7753. ; 63:1, s. 41-45
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Tidskriftsartikel (refereegranskat)abstract
- Lithium-graphite intercalation compounds were synthesised in an electrochemical cell by the application of a series of current pulses, during which nonequilibrium distributions of intercalation phases were created in the graphite. The phase formation and
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