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Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
The resistance thermometer relies on the increase in resistance of a metal wire with increasing temperature. As the electrons in the metal gain thermal energy, they move about more rapidly and undergo more frequent collisions with each other and the atomic nuclei. These scattering events reduce the mobility of the electrons, and since resistance is inversely proportional to mobility, the resistance increases. Resistance thermometers usually consist of a coil of fine metal wire. Platinum wire gives the largest linear temperature range of operation. To determine the resistance, a constant current is supplied and the voltage is measured. A resistance measurement can be made by placing the resistor in the sensing arm of a Wheatstone bridge and adjusting the opposing resistor to “balance” the bridge, which produces a null output. A measure of the sensitivity of a resistance thermometer is its temperature coefficient of resistance: TCR =(ΔR/R)(1/ΔT), in units of percent resistance per degree of temperature.
Thermal Sensors
Published in John Vetelino, Aravind Reghu, Introduction to Sensors, 2017
Other, less popular metal resistance thermometers use copper (Cu), iridium (Ir), or combinations of rhodium and cobalt (Rh-Co) or platinum and cobalt (Pt-Co). The Cu thermometer is the most linear, but it has a limited temperature range (0 to 100°C). The Ir thermometer provides an excellent match to aluminum substrates and is normally used as a thin film in surface temperature measurements. Rh-Co and Pt-Co are used primarily for low-temperature (.5 to 30 K) applications.
Application in Superconducting Quantum Interference Devices SQUIDs
Published in Edward Wolf, Gerald Arnold, Michael Gurvitch, John Zasadzinski, Josephson Junctions, 2017
SQUIDs can be used to design powerful thermometers for temperature measurements in the low and ultralow temperature range. For a practical thermometer, a good thermal contact to the location where the temperature has to be measured and negligible heating effects by the thermometer itself are crucial, in particular at millikelvin temperatures. Resistance thermometers are based on measuring the temperature-dependent resistivity of the sensor. They have to be calibrated and need an excitation signal for operation which can cause heating problems. External excitation can be omitted and consequently heating effects be minimized if the thermal noise in a conducting sensor is measured rather than the resistivity. Such noise thermometers relate the measured noise voltage or current to the thermodynamic temperature via the wellknown Nyquist formula. Due to its low intrinsic noise, the SQUID is well suited for noise thermometry (for a review see Chapter 9.4 in [6]).
Techno-economic analysis of In-stream technology: A review
Published in International Journal of Green Energy, 2023
Upendra Bajpai, Sunil Kumar Singal
The density of water is measured with vented cabled temperature-pressure sensors. A platinum resistance thermometer with a temperature range of−5°C to 50°C, an accuracy of ±0.1°C, and a precision of 0.01°C is used in the temperature sensor. The density of water changes with temperature. The variation in the temperature of water available in rivers, canals, and sea is negligible because of the considerable amount of water. That’s why the density of the water is assumed as constant (Neary and Gunawan 2011; Sood and Singal 2019).
Thermoeconomic performance optimization of an orifice pulse tube refrigerator
Published in Science and Technology for the Built Environment, 2020
Debashis Panda, Ashok K. Satapathy, Sunil K. Sarangi
A total of eight temperature sensors (PT-100 Ω resistance thermometers, type: thin film type, range: –200 °C to 200 °C, response time: 0.25 s) are fixed at different locations of the regenerator, pulse tube, cold, and hot heat exchangers to measure the temperature as depicted in Figure 14. Along longitudinal positions of tube and regenerator wall, platinum resistance thermometers are connected to measure the temperature. A feedthrough is placed at the warm end of vacuum chamber through which sensors are entered into the vacuum chamber. For temperature measurement ADAM modules and a 16 channel RTD scanner is adopted as data acquisition system. Temperature sensors are connected with the walls at different positions as shown in Figure 14 and fixed with Teflon tapes, the other end is connected with ADAM 4000 series (ADVANTECH 2019) data acquisition module. By ASCII commands and RS-485 protocols the ADAM 4000 series intelligent sensors are controlled with the computer interface modules. The COM ports of RS-485 network are connected to the host computer through the ADAM RS-232/RS-485 converter, which sends the host signals to the correct RS-485 protocol. One 6-channel data acquisition module (4015, Input type: PT 100Ω, −200 °C to 200 °C, Isolation voltage: 3000 VDC, Sampling Rate: 10 samples/second, Input impedance: 10 MΩ, Resolution: 16-bit, CMR @50/60 Hz: 120 dB, NMR@50/60 Hz: 100 dB, Span Drift: ±25 ppm/ °C, Zero Drift: ±3µV/ °C, Power consumption: 1.2W @ 24VDC, accuracy ±0.1%) has been placed to acquire all the signals. The output voltages obtained from different sensors varies from millivolt to volt range. The outputs of ADAM data acquisition system are then connected with PC to record the temperature fluctuation. Due to the limitations in ADAM, only temperature fluctuations at six different locations have been recoded. At the middle of the regenerator and tube, temperatures are not measured for this particular experiment. A manganin wire (resistance ∼30.01 ± 0.027 Ω) is wound over the cold heat exchanger to measure the heat load. A source is placed to apply AC voltage; a current-voltage and power meter meter is placed to measure the current, voltage, and power. An energy meter is placed to measure the input electric power to helium compressor.