| 1. |
- Eriksson, Gunnar, et al.
(författare)
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Combustion of wood hydrolysis residue in a 150 kW powder burner
- 2004
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 83:11-12, s. 1635-1641
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Tidskriftsartikel (refereegranskat)abstract
- A combustion test has been made with residues from hydrolysis of wood for fuel ethanol production. A 150 kW powder burner was used. Fuel feeding and combustion were stable. The average concentration of CO in the stack gas was 8 mg/MJ, the average concentration of NOx was 59 mg/MJ and the average total hydrocarbon concentration was below 1 ppm, at an average O2-concentration of 4.6%. The low contents of potassium and sodium in the hydrolysis residue make the material attractive as a gas turbine fuel and the conclusion of this test is that direct combustion may be a feasible approach for gas turbine applications.
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| 2. |
- Andersson, Magnus, et al.
(författare)
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Vortex liquid properties in optimally doped and oxygen-deficient YBa2Cu3O7-delta single crystals
- 2000
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Ingår i: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 332:1-4, s. 86-92
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Tidskriftsartikel (refereegranskat)abstract
- The electrical anisotropy, gamma = (m(c)/m(ab))(1/2), can easily be varied by changing the oxygen content in single crystals of YBa2Cu3O7-delta (YBCO); thus making this system useful as a test system For vortex dynamics in high-temperature superconductors (HTSC). Here, some recent results are reviewed. Measurements of the c-axis resistivity with the magnetic field B II ab-plane is shown to be a powerful tool in studying vortex velocity correlations both parallel and perpendicular to the applied field. In optimally doped crystals, we iind evidence that the in-plane vortex lattice melts at T-m into a disentangled vortex liquid, which looses its correlation along the c-axis at a higher temperature T-br > T-m. For weakly disordered crystals and magnetic fields B \\ c-axis, a relation between the vortex glass line and the magnetic field dependence of the characteristic energy, U*, in the pinned vortex liquid is proposed. This approach is shown to give support to our idea of describing the vortex glass resistivity in the liquid regime by a modified glass correlation Length, xi(g) = xi(0)\k(B)T/U-0 - 1\(-nu) which depends on the average pinning energy, Lr,, in the system [A. Rydh, O. Rapp, M. Andersson, Phys. Rev. Lett. 83 (1999) 1850].
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| 3. |
- Andersson, Magnus, et al.
(författare)
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Vortex liquid-to-solid transition in underdoped YBa2Cu3O7-delta single crystals with B parallel to ab
- 2003
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Ingår i: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 388, s. 691-692
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Tidskriftsartikel (refereegranskat)abstract
- A nearly magnetic field independent vortex liquid-to-solid transition has been observed in both the ab-plane and in the c-axis resistivity of underdoped YBa2Cu3O7-delta single crystals for magnetic fields Bparallel toab-plane. These observations suggest that intrinsic pinning caused by the superconducting layers do neither lead to a system of completely decoupled superconducting layers nor to a smectic vortex phase at high fields. A possible explanation may include a transition driven by changes in elastic properties (e.g., the shear modulus) of the vortex system.
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| 4. |
- Cederström, Björn, et al.
(författare)
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Focusing hard X-rays with old LPs
- 2000
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 404:6781, s. 951-951
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Cederström, Björn, 1973-, et al.
(författare)
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Multi-prism x-ray lens
- 2002
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 81:8, s. 1399-1401
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Tidskriftsartikel (refereegranskat)abstract
- Refractive x-ray lenses with a triangular surface profile have been used to focus a synchrotron beam to sub-mum line width. These lenses are free from spherical aberration and work in analogy with one-dimensional focusing parabolic compound refractive lenses. However, the focal length can be easily varied by changing the gap between the two jaws. Silicon lenses were fabricated by wet anisotropic etching, and epoxy replicas were molded from the silicon masters. The lenses provided intensity gains up to a factor of 32 and the smallest focal line width was 0.87 mum. The simplified geometry and associated fabrication technique open possibilities for low-Z materials such as beryllium, which should greatly enhance the performance of refractive x-ray optics. (C) 2002 American Institute of Physics.
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| 6. |
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| 7. |
- Fernando, W. Primal D., et al.
(författare)
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Propane Heat Pump with Low Refrigerant Charge : Design and Laboratory Tests
- 2004
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Ingår i: International journal of refrigeration. - : Elsevier BV. - 0140-7007 .- 1879-2081. ; 27:7, s. 761-773
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Tidskriftsartikel (refereegranskat)abstract
- Independently of the choice of refrigerant, environmental and or safety issues can be minimised by reducing the amount of refrigerant charge per heat pump or refrigeration system. In the investigation reported here, a laboratory test rig was built, simulating a water-to-water heat pump with a heating capacity of 5 kW. The system was designed to minimize the charge of refrigerant mainly by use of mini-channel aluminium heat exchangers. It was shown that the system could be run with 200 g of propane at typical Swedish operating conditions without reduction of the COP compared to a traditional design. Additional charge reduction is possible by selecting proper compressor lubrication oils or by using a compressor with less lubrication oil.
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| 8. |
- Fernando, W. Primal D., et al.
(författare)
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The Solubility of Propane (R290) with Commonly Used Compressor Lubrication Oils
- 2003
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Ingår i: Compressors and Their Systems. - 1860584179 ; , s. 157-166
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Konferensbidrag (refereegranskat)abstract
- An ongoing project called "Charge minimisation of a small capacity heat pump" is aimed to minimise the refrigerant charge in heat pumps, refrigeration and air-conditioning systems. The experimental heat pump was run with propane as refrigerant and the designed heat capacity (condenser capacity) was over 5kW. Tests were done to investigate the refrigerant charge distribution in different sections of the heat pump, while it was running. The experiments done so far have shown that the amount of refrigerant in the compressor is higher than expected. This paper presents the measured refrigerant masses in a hermetic scroll compressor together in suction line and the calculated refrigerant mass dissolved in the compressor lubrication oil at different evaporation temperatures. Finally, solubility tests of propane with different lubricating oils are presented. The tests show that the propane is more soluble in POE than PAG oils.
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| 9. |
- Lundqvist, Anna, et al.
(författare)
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Neuropsychological aspects of driving after a stroke : in the simulator and on the road
- 2000
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Ingår i: Applied Cognitive Psychology. - 0888-4080. ; 14:2, s. 135-150
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Tidskriftsartikel (refereegranskat)abstract
- Thirty patients with stroke and 30 matched controls participated in the study (mean age 68 years, mean interval since stroke onset 8.6 months). The patients performed significantly worse on cognitive and attentional processing measured by a neuropsychological test battery. The patients had significantly greater difficulty in allocating processing resources to a secondary information processing task during driving in an advanced simulator. The patients performed worse driving in real traffic, and had less driving skill; fifty per cent did not pass the driving test. The neuropsychological test battery showed a pattern with three factors: (1) attentional processing (2) executive capacity, and (3) cognitive processing. Regression models based on simulator driving variables and neuropsychological test variables respectively, overall classified correctly in 85% and 83% of the cases with respect to driving skill. Decreased cognitive and attentional processing were suggested to be associated with an overall speed impairment.
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| 10. |
- Lundqvist, Björn, et al.
(författare)
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Experimental evidence for a three-dimensional-two-dimensional crossover for magnetic fields parallel to the ab plane in oxygen-deficient single crystals of YBa2Cu3O7-delta
- 2000
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 62:5, s. 3542-3546
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Tidskriftsartikel (refereegranskat)abstract
- Resistive measurements on oxygen-deficient YBa2Cu3O7-delta single crystals of varying anisotropy gamma (22 less than or equal to gamma less than or equal to 36) have been used for investigations of the transition into a glassy vortex state for magnetic fields 0 less than or equal to B less than or equal to 12 T parallel to the ab plane. When B is accurately aligned parallel to the nb plane there is a remarkable change in behavior to a field-independent vortex solid-to-liquid transition at high magnetic fields. A possible explanation is suggested for the vertical transition involving a complete decoupling of the superconducting planes that leads to a two-dimensional system where the resistivity is given by nucleation of vortex-antivortex pairs.
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