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1	Optimal Sensor Placement for Structural Health Monitoring Movva, Gopichand 12 1900 (has links) In large-scale civil structures, a limited number of sensors are placed to monitor the health of civil structures to reduce maintenance, communication and energy costs. In this thesis, the problem of optimal sensor location placement to infer the health of civil structures is explored. First, a comparative study of approaches from the fields of control engineering and civil engineering is conducted . The widely used civil engineering approaches such as effective independence (EI) and modal assurance criterion (MAC) have limitations because of the negligence of modes and damping parameters. On the other hand, control engineering approaches consider the entire system dynamics using impulse response-type sensor measurement data. Such inference can be formulated as an estimation problem, with the dynamics formulated as a second-order differential equation. The comparative study suggests that damping dynamics play significant impact to the selection of best sensor location---the civil engineering approaches that neglect the damping dynamics lead to very different sensor locations from those of the control engineering approaches. In the second part of the thesis, an initial attempt to directly connect the topological graph of the structure (that defines the damping and stiffness matrices) and the second-order dynamics is conducted. sensor placement Eigenvalue estimation damping dynamics effective independence state estimation
2	Modeling The Temperature of a Calorimeter at Clab : Considering a Thermodynamic Model of The Temperature Evolution of The Calorimeter System 251 Ekman, Johannes January 2021 (has links) It is important to know the heat generated due to nuclear decay in the final repository for spent nuclear fuel. In Sweden, the heating powers generated in spent nuclear fuels are currently measured in the calorimeter System 251 at the Clab facility, Oskarshamn. In order to better measure, and increase understanding, of the temperature measurements in the calorimeter, a simple thermodynamic model of its temperature evolution was developed. The model was described as a system of ordinary differential equations, which were solved, and the solution was applied to calibration measurements of the calorimeter. How precise the model is, how its parameters affect the model, et cetera, are addressed. How the temperature evolution of the system changes as the values of parameters in the model are changed is addressed. The mass correction of the calorimeter could be estimated from this model, which validated the established mass correction of the calorimeter. How the measurement results from the calorimeter would be affected if the volume of the calorimeter was changed was also considered. Additionally, gamma radiation escape from the calorimeter without being detected as heat in the calorimeter. The gamma escape energy fraction was estimated by SERPENT simulations of the calorimeter, as a function of the initial photon energy. The gamma escape was also estimated for different values of the radius of System 251. calorimetry calorimeter System 251 temperature evolution spent nuclear fuel SNF MATLAB SERPENT2 Clab nuclear decay heat calibration measurements thermodynamic model gamma escape fraction mass correction calibration measurements electric heater three component system eigenvalues eigenvalue estimation temperature increase method sensitivity of mass correction calorimeter heat capacity mass correction uncertainty calorimeter calibration curve monoenergetic gamma spectrum Subatomic Physics Subatomär fysik Other Physics Topics Annan fysik

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Optimal Sensor Placement for Structural Health Monitoring

Modeling The Temperature of a Calorimeter at Clab : Considering a Thermodynamic Model of The Temperature Evolution of The Calorimeter System 251