Nisabha Jayasundere | University of Ruhuna (original) (raw)
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Papers by Nisabha Jayasundere
The backscattering from partially water-filled cylindrical shells has been studied using finite e... more The backscattering from partially water-filled cylindrical shells has been studied using finite element (FE) analysis and experimental measurements for low to medium frequencies, corresponding to 2 < ka < 30 (where a is the shell outer radius). For a partially-filled shell, filled to three quarters of the inner diameter, backscattering has been investigated numerically as a function of the elevation angle of the incident wave, and in particular as the wave direction changes from horizontal to vertical. Comparisons with fully air-filled and fully water-filled shells indicate that the shell resembles the former when the wave is incident from above and the latter when the wave is incident horizontally. The experiments were performed in a reservoir, using horizontal incidence and wideband Ricker pulses generated by a parametric array. The short duration of the Ricker pulses made it possible to observe a number of returns after the specular return for a shell with a high filling fr...
The backscattering from partially water-filled cylindrical shells has been studied using finite e... more The backscattering from partially water-filled cylindrical shells has been studied using finite element (FE) analysis and experimental measurements for low to medium frequencies, corresponding to 2 < ka < 30 (where a is the shell outer radius). For a partially-filled shell, filled to three quarters of the inner diameter, backscattering has been investigated numerically as a function of the elevation angle of the incident wave, and in particular as the wave direction changes from horizontal to vertical. Comparisons with fully air-filled and fully water-filled shells indicate that the shell resembles the former when the wave is incident from above and the latter when the wave is incident horizontally. The experiments were performed in a reservoir, using horizontal incidence and wideband Ricker pulses generated by a parametric array. The short duration of the Ricker pulses made it possible to observe a number of returns after the specular return for a shell with a high filling fraction; these included contributions due to S 0 waves generated at the front and back walls of the shell, and the back wall return. Inversion of the FE model data enabled the expected waveforms to be predicted; the measurements were in very good agreement with the predictions.
Laptop coolers are external devices, which are ancillaries to the existing cooling mechanism of l... more Laptop coolers are external devices, which are ancillaries to the existing cooling mechanism of laptops, in order to reduce their internal temperature. Available coolers do not provide efficient cooling in high ambient temperatures. This paper presents the implementation of an intelligent laptop cooler, which can vary its performance according to the laptop temperature and ambient temperature, and actively cool the air flow by using thermoelectric coolers (TECs). In this work, a dynamic airflow is intelligently cooled by the device and the process will be controlled, based on the feedback provided by a temperature sensor placed at exhaust vent of the laptop. Further, the device is designed to reduce dust content in the air flow which passes through the laptop. Ultimately an effective cooling is provided to the laptop through this device while increasing the lifetime of the laptop.
The backscattering from partially water-filled cylindrical shells has been studied using finite e... more The backscattering from partially water-filled cylindrical shells has been studied using finite element (FE) analysis and experimental measurements for low to medium frequencies, corresponding to 2 < ka < 30 (where a is the shell outer radius). For a partially-filled shell, filled to three quarters of the inner diameter, backscattering has been investigated numerically as a function of the elevation angle of the incident wave, and in particular as the wave direction changes from horizontal to vertical. Comparisons with fully air-filled and fully water-filled shells indicate that the shell resembles the former when the wave is incident from above and the latter when the wave is incident horizontally. The experiments were performed in a reservoir, using horizontal incidence and wideband Ricker pulses generated by a parametric array. The short duration of the Ricker pulses made it possible to observe a number of returns after the specular return for a shell with a high filling fr...
The backscattering from partially water-filled cylindrical shells has been studied using finite e... more The backscattering from partially water-filled cylindrical shells has been studied using finite element (FE) analysis and experimental measurements for low to medium frequencies, corresponding to 2 < ka < 30 (where a is the shell outer radius). For a partially-filled shell, filled to three quarters of the inner diameter, backscattering has been investigated numerically as a function of the elevation angle of the incident wave, and in particular as the wave direction changes from horizontal to vertical. Comparisons with fully air-filled and fully water-filled shells indicate that the shell resembles the former when the wave is incident from above and the latter when the wave is incident horizontally. The experiments were performed in a reservoir, using horizontal incidence and wideband Ricker pulses generated by a parametric array. The short duration of the Ricker pulses made it possible to observe a number of returns after the specular return for a shell with a high filling fraction; these included contributions due to S 0 waves generated at the front and back walls of the shell, and the back wall return. Inversion of the FE model data enabled the expected waveforms to be predicted; the measurements were in very good agreement with the predictions.
Laptop coolers are external devices, which are ancillaries to the existing cooling mechanism of l... more Laptop coolers are external devices, which are ancillaries to the existing cooling mechanism of laptops, in order to reduce their internal temperature. Available coolers do not provide efficient cooling in high ambient temperatures. This paper presents the implementation of an intelligent laptop cooler, which can vary its performance according to the laptop temperature and ambient temperature, and actively cool the air flow by using thermoelectric coolers (TECs). In this work, a dynamic airflow is intelligently cooled by the device and the process will be controlled, based on the feedback provided by a temperature sensor placed at exhaust vent of the laptop. Further, the device is designed to reduce dust content in the air flow which passes through the laptop. Ultimately an effective cooling is provided to the laptop through this device while increasing the lifetime of the laptop.