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| 2. |
- Appelgren, Patrik, et al.
(författare)
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Interaction between solid copper jets and powerful electrical current pulses
- 2011
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Ingår i: Journal of applied mechanics. - : ASME International. - 0021-8936 .- 1528-9036. ; 78:2
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between a solid copper jet and an electric current pulse is studied. Copper jets that were created by a shaped-charge device were passed through an electrode configuration consisting of two aluminum plates with a separation distance of 150 mm. The electrodes were connected to a pulsed-power supply delivering a current pulse with amplitudes up to 250 kA. The current and voltages were measured, providing data on energy deposition in the jet and electrode contact region, and flash X-ray diagnostics were used to depict the jet during and after electrification. The shape of, and the velocity distributions along, the jet has been used to estimate the correlation between the jet mass flow through the electrodes and the electrical energy deposition. On average, 2.8 kJ/g was deposited in the jet and electrode region, which is sufficient to bring the jet up to the boiling point. A model based on the assumption of a homogenous current flow through the jet between the electrodes underestimates the energy deposition and the jet resistance by a factor 5 compared with the experiments, indicating a more complex current flow through the jet. The experimental results indicate the following mechanism for the enhancement of jet breakup. When electrified, the natural-formed necks in the jet are subjected to a higher current density compared with other parts of the jet. The higher current density results in a stronger heating and a stronger magnetic pinch force. Eventually, the jet material in the neck is evaporated and explodes electrically, resulting in a radial ejection of vaporized jet material.
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| 6. |
- Carlsson, Torgny E., et al.
(författare)
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Development of a 3D camera
- 1999
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Ingår i: Proceedings of SPIE. ; , s. 218-224
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Konferensbidrag (refereegranskat)abstract
- In the development of new products there are two parallel lines for the development process to follow; the traditional or 'real,' and the new computer aided or 'virtual.' The traditional line is to develop prototypes that can be used for testing strength, functionality, and visual appearance of the product. In the virtual line digital (CAD) models are developed which can be tested entirely in a computer by simulations e.g., using Finite Element Analysis (FEA) and other tools. For transformation from the real to the virtual world some kind of 3D camera is needed. The shape of the model should be measured together with further data concerning the visual appearance, material properties, etc. We have developed electronic recording techniques for doing this based on the Light-in-Flight technique. This technology has all advantages of holography, i.e., apart from the shape it is also possible to measure how much light is reflected from different parts of the object along with interferometric information, which can give mechanical data for the object. This can be used for example for visualization and to give tactile and haptic information to a virtual reality system about how the object would be perceived by a person touching it.
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| 7. |
- Carlsson, Torgny E., et al.
(författare)
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Method for fringe enhancement in holographic interferometry for measurement of in-plane displacements
- 1998
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Ingår i: Applied Optics. - : Optical Society of America. - 0003-6935 .- 1539-4522. ; 37:10, s. 1845-1848
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Tidskriftsartikel (refereegranskat)abstract
- Theoretical background along with experimental results are given for a simple method for in-plane fringe enhancement in dual-beam illumination holographic interferometry. In this method, the fringes representing in-plane displacements arise as a moirépattern between two interferograms. To distinguish the in-plane displacement, a sequence of images is recorded while the reference mirror is continuously tilted at random. The in-plane fringes arethen found as the maximum contrast of the out-of-plane fringes in the image sequence. The resulting fringe quality is close to the quality of the out-of-plane fringes.
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| 8. |
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| 9. |
- Carlsson, Torgny E., et al.
(författare)
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System for acquisition of three-dimensional shape and movement using digital Light-in-Flight holography
- 2001
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Ingår i: Optical Engineering. - : SPIE-Intl Soc Optical Eng. - 0091-3286 .- 1560-2303. ; 40:1, s. 67-75
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Tidskriftsartikel (refereegranskat)abstract
- In the development of new products there are two parallel lines for the development process to follow: the traditional or "real" and the new computer aided or "virtual." The traditional line is to develop prototypes that can be used for testing strength, functionality, and visual appearance of the product. In the virtual line digital (CAD) models are developed that can be tested entirely in a computer by simulations, e.g., using finite element analysis (FEA) and other tools. For transformation from the real to the virtual world some kind of 3-D acquisition system is needed. The shape of the model should be measured together with further data concerning the visual appearance, material properties, etc. We develop electronic recording techniques for doing this based on the Light-in-Flight technique. This technology has all the advantages of holography, i.e., apart from the shape it is also possible to measure how much light is reflected from different parts of the object along with interferometric information, which can give mechanical data for the object. This can be used, for example, for visualization and to give tactile and haptic information to a virtual reality system about how the object would be perceived by a person touching it.
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| 10. |
- Mattsson, Roger, et al.
(författare)
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Pulsed TV holography and schlieren studies, and large eddy simulations of a turbulent jet diffusion flame
- 2004
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180 .- 1556-2921. ; 139:1-2, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- In the search for an improved understanding of jet-flame dynamics we here compare predictions from large-eddy simulations (LES) and measurements using schlieren and holographic interferometry of a round turbulent jet diffusion flame. The studies concern a turbulent propane-air (C3H8-O-2/N-2) diffusion flame under ambient conditions at a Reynolds number of Re = 10(4). The interferometric measurements were performed with an all-electronic method, pulsed TV holography, using a pulsed laser and a fast charge coupled device (CCD) camera. The LES calculations use the probability density function (PDF) flamelet approach with a beta function as the probability density function, whereas the subgrid turbulence is modeled with a one-equation eddy viscosity model. In order to validate the LES model quantitative comparisons of first-order statistical moments of the velocity were first made with available data for nonreactive jets. The LES model captures the statistics well. The next step in the validation process concerns comparing the jet-flame development between LES and the schlieren and pulsed TV holography data. To this end the results of the LES calculations were used to simulate instantaneous interference patterns using ray tracing. The LES model describes the overall behavior of the flame successfully.
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