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| 2. |
- Hanstorp, Karl, et al.
(författare)
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Numerical Simulation and Experimental Scheme for Monitoring Hoof Wall Structure and Health in Sport Horses
- 2016
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Ingår i: Proceedings of the 4th International Congress on Sport Sciences Research and Technology Support. - : SCITEPRESS - Science and Technology Publications. - 9789897582059 ; , s. 171-175
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Konferensbidrag (refereegranskat)abstract
- This study provides a computational model developed to demonstrate the possibility of monitoring hoof structure and health in equestrian sport. This is achieved by employing finite element simulation of threedimensional heat flow from a surface heat source into a hoof structure while simultaneously sensing the surface temperature. The time evolution of the recorded surface temperature, transient curve, is used to investigate hoof structure and predict its intactness by comparing these curves for three different models. We have observed differences between the transient curves obtained from a normal hoof structure, a hoof structure containing a foreign material and hoof capsule subjected to wall separation. An experimental method for probing hoof profile was briefly discussed. It uses temperature sensor/heat source. The method can determine the thermal conductivity of the hoof along the hoof structure from the recorded transient curve. Thus, it displays the hoof structure by utilizing the thermal conductivity variation between the hoof parts.
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| 3. |
- Hartman, Steven, 1965-, et al.
(författare)
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Om Thoreaus Walden
- 2006
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Ingår i: Walden. - Stockholm : Natur och Kultur. - 9789127113619 - 9789127119567 ; , s. 398-421
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Reception history of Thoreau's Walden in Sweden, the UK and the USA, including original discussion and analysis of the work from multiple critical vantage points.
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| 4. |
- Mekonnen Mihiretie, Besira, 1983, et al.
(författare)
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Finite element modeling of the Hot Disc method
- 2017
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Ingår i: International Journal of Heat and Mass Transfer. - : Elsevier BV. - 0017-9310. ; 115, s. 216-223
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Tidskriftsartikel (refereegranskat)abstract
- The Hot Disc method, also known as the transient plane source (TPS) technique, is an experimental approach to determine the thermal transport properties of materials. The core of the method is the Hot Disc sensor, an electrically conducting metallic strip, shaped as a double spiral clad with a protective polymer film. The mean temperature increase in the sensor has been approximated from various analytical approaches such as: the concentric ring sources model, the thermal quadrupoles formalism, and concentric circular strips structure approach. However, full numerical simulation of the sensor has not been addressed so far. Here we develop a 3D model of Hot Disc sensors and compare simulated mean temperature increase to experimental recordings. Joule heating coupled with heat transfer of solids (of COMSOL Multiphysics software) is used to simulate the working principle of the sensor. The volume mean temperature increase in the sensor from the simulations proves to be in a good agreement with the corresponding experimental recordings. The temperature distributions of the metallic strip are also evaluated and discussed with respect to the previous experimental findings. Furthermore, the current distribution across the strip is obtained. Such simulation can potentially be used in further optimizing geometry and parameter estimation.
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| 5. |
- Mekonnen Mihiretie, Besira, 1983, et al.
(författare)
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SIMULATION OF THE HOT DISK SENSOR: TEMPERATURE AND ELECTRIC CURRENT DISTRIBUTION
- 2017
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Ingår i: Proceedings of the Asian Conference on Thermal Sciences 2017.
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Konferensbidrag (refereegranskat)abstract
- The Hot Disk method, also known as the transient plane source (TPS) technique, is an experimental approach for determining the thermal transport properties of materials. The core of the method is the Hot Disk sensor, an electrically conducting metallic foil (typically nickel), shaped as a double spiral, clad with a protective polymer film or mica. The double spiral serves simultaneously as heat source and temperature probe. The mean temperature increase of the TPS- sensor has been formulated from various analytical approaches such as: the concentric ring sources model, the thermal quadrupoles formalism, and concentric circular strips structure approach. However, full numerical simulation of the sensor has not been addressed so far. Here we develop 3D model of a Hot Disk sensor. The simulation provides information such as temperature and current distribution along each spiral which is not accessible from the experiment. Modeling feature, Joule heating coupled with heat transfer in solids of COMSOL Multiphysics software is used to simulate the sensor. The temperature and current distributions along the nickel wire is obtained. This can potentially be used in further optimizing geometry and estimating better parameters.
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| 6. |
- Mekonnen Mihiretie, Besira, 1983, et al.
(författare)
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Thermal depth profiling of materials for defect detection using hot disk technique
- 2016
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226. ; 6:8
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Tidskriftsartikel (refereegranskat)abstract
- A novel application of the hot disk transient plane source technique is described. The new application yields the thermal conductivity of materials as a function of the thermal penetration depth which opens up opportunities in nondestructive testing of inhomogeneous materials. The system uses the hot disk sensor placed on the material surface to create a time varying temperature field. The thermal conductivity is then deduced from temperature evolution of the sensor, whereas the probing depth (the distance the heat front advanced away from the source) is related to the product of measurement time and thermal diffusivity. The presence of inhomogeneity in the structure is manifested in thermal conductivity versus probing depth plot. Such a plot for homogeneous materials provides fairly constant value. The deviation from the homogeneous curve caused by defects in the structure is used for inhomogeneity detection. The size and location of the defect in the structure determines the sensitivity and possibility of detection. In addition, a complementary finite element numerical simulation through COMSOL Multiphysics is employed to solve the heat transfer equation. Temperature field profile of a model material is obtained from these simulations. The average rise in temperature of the heat source is calculated and used to demonstrate the effect of the presence of inhomogeneity in the system.
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