| 1. |
- Li, Martin, et al.
(författare)
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On the use of second-order derivatives of track irregularity for assessing vertical track geometry quality
- 2012
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 50:SUPPL. 1, s. 389-401
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Tidskriftsartikel (refereegranskat)abstract
- This paper studies the use of second-order derivatives of track irregularities (longitudinal level, LL) for assessing vertical track geometry quality. Both a single-degree-of-freedom and a three-DOF vehicle-track model are investigated in order to explain theoretically why from the aspect of vehicle-track dynamic interaction it is relevant to consider not only the amplitudes of LL but also their second-order derivatives (LL2). Simulation results are then presented to demonstrate that dynamic vertical track forces are more correlated with the second-order derivatives (LL2) than to the amplitudes (LL) themselves. A comparison of the power spectral density (PSD) spectra for typical track reveals that it is more convenient to use the PSD spectra for the second-order derivatives than for the amplitudes, as the curves for the second-order derivatives are flat within the short wavelength range. Finally, the practical use of derivatives within the maintenance management system in order to achieve improved assessment of track geometry quality is also discussed.
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| 2. |
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| 3. |
- Spännar, Jan, et al.
(författare)
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A method for measuring strip temperature in the steel industry
- 2005
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456. ; 51:6
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Tidskriftsartikel (refereegranskat)abstract
- In the steel industry, there are many processes that include measuring and control of temperatures. With higher demand on quality, increased production, and effective energy consumption, the use of noncontact temperature measuring techniques has increased. After the cooling section in a continuous annealing-pickling line, the strip temperature is estimated by using the grey box technique. Temperatures are measured in the cavity between the strip and the roller using radiation thermometers. A model is made for estimating strip temperature using the measured temperatures and knowledge of the physics of the process.
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| 4. |
- Spännar, Jan, et al.
(författare)
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A method for measuring strip temperature in the steel industry
- 2002
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 51:6, s. 1240-1245
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Tidskriftsartikel (refereegranskat)abstract
- In the steel industry, there are many processes that include measuring and control of temperatures. With higher demand on quality, increased production, and effective energy consumption, the use of noncontact temperature measuring techniques has increased. After the cooling section in a continuous annealing-pickling line, the strip temperature is estimated by using the grey box technique. Temperatures are measured in the cavity between the strip and the roller using radiation thermometers. A model is made for estimating strip temperature using the measured temperatures and knowledge of the physics of the process.
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| 5. |
- Spännar, Jan, et al.
(författare)
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Estimation of a non-measurable variable by using Grey box modelling
- 2001
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Ingår i: Proceedings of the 18th IEEE Instrumentation and Measurement Technology Conference, 2001. IMTC 2001. - 0780366468 ; , s. 778-783
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the steel industry, there are many processes that include measuring and control of temperatures. With higher demand on quality, increased production and effective energy consumption the use of non-contact temperature measuring techniques has increased. After the cooling section in a continuous annealing-pickling line, the strip temperature is estimated by using the Grey box technique. Temperatures are measured in the cavity between the strip and the roller using radiation thermometers. A model is made for estimating strip temperature using the measured temperatures and knowledge of physics of the process.
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| 6. |
- Spännar, Jan, et al.
(författare)
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Estimation of a Non-Measurable Variable Using Grey Box Modelling
- 2001
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Ingår i: IEEE Instrumentation and Measurement Technology Conference. - Budapest.
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Konferensbidrag (refereegranskat)abstract
- In the steel industry, there are many processes that include measuring and control of temperatures. With higher demand on quality, increased production and effective energy consumption the use of non-contact temperature measuring techniques has increased. A model is developed for estimating strip temperature using measured temperatures and knowledge of physics of the process.
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| 7. |
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| 8. |
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| 9. |
- Spännar, Jan, et al.
(författare)
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Modelling and identification of an air cooling process
- 1997
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Ingår i: Proceedings of the 1997 IEEE international conference on control applications. - New York : IEEE. ; , s. 383-385
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents modelling and identification of an air cooling process in a steel strip line. The model is derived from the heat balance equation. The distributed parameter system is approximated with a discrete non-linear lumped parameter model. The model accuracy is evaluated with actual operation data and the unknown parameters of the model are estimated off-line. The number of unknown parameters is first reduced and then extended until an appropriate model is achieved. The model is intended to be used in strip temperature control, fault detection and as a basis for a decision on future rebuilding of the system.
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