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  • The development and performance analysis of a Cold Electronic LC oscillator is discussed. This is a part of the sensor system being developed for a Residual Resistivity Ratio (RRR) measurement system. In this paper, the effect of temperature variation on cold electronics based LC Oscillator is analysed. This variation in temperature causes oscillator to change its operating frequency. Certain additional harmonics are also introduced into the output waveform at the lower temperatures. This cold electronics based LC oscillator is used as the signal conditioning element for a Residual Resistivity Ratio (RRR) measuring sensor. LabVIEW 11.0 software is used to log the frequency variations for different temperature from 300 K to 4.2 K.
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    • Dataset
  • One of the active approaches for regulating heat transfer in a convection-dominated cavity system is to use a periodic moving object. This study conducted a numerical study on the impact of an oscillating air-supply guide vane on the transient behaviour of thermo-hydraulic field within a square cavity with single inlet and outlet ports. The CFD package software, ANSYS FLUENT, was employed to perform the numerical simulation. The numerical analysis focused on the effect of frequency and amplitude of an oscillating guide vane on the internal flow distribution and heat transfer performance. According to the numerical results, it is known that the instantaneous Nusselt number presents cyclical changes. Moreover, the instantaneous Nusselt number increases with the increase of amplitude as the frequency is fixed. At fixed amplitude, the instantaneous Nusselt number decreases as the frequency increases.
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    • Dataset
  • A compact torsionally oscillating crystal viscometer was used to measure viscosity coefficients of R 32, R 134a and R 1234ze(Z). To derive viscosity coefficients, resonance frequencies and bandwidths of the crystal were automatically measured with a developed measuring system and its software. Viscosity data of R 32, R 134a and R 1234ze(Z) were measured at temperatures ranging from 303 to 450 K at pressures up to 20 MPa in their liquid regions. The uncertainty of the measurements was estimated to be about 5 %. The experimental data of R 134a were compared with calculated data from a correlation.
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    • Dataset
  • This study deals with simulations of heat transfers between a 1 mm thick gadolinium plate submitted to a variable magnetic field and an oscillating liquid flow. The channel is connected to a cold thermal source (Tc = 290 K) and to a hot thermal source (Th = 295 K). The volume source term for the energy equation in the gadolinium plate is computed for each time step. Simulations were performed with the Fluent CFD code for a frequency f = 1Hz. The influence of the channel volume displacement was investigated. The evolution of the temperature distribution in the plate for different volume rates shows that the gradient reaches a maximum value in the plate for a volume rate displacement of 40%. This is confirmed by the determination of the enthalpy variation of the liquid located in the thermal source. Simulations for f = 2Hz clearly show the diminution of the enthalpy variations and consequently a sharp diminution of the possibility of heat transfer between the sources.
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    • Dataset