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Applications of Sensors to Physical Measurements
Published in Robert B. Northrop, Introduction to Instrumentation and Measurements, 2018
Scientific temperature measurements are generally made using the Celsius (centigrade) or Kelvin scales. Absolute zero (thermodynamic zero) occurs at 0 K or –273.15°C. That is, K = °C + 273.15. While most of the civilized world uses the Celsius scale for such mundane things as cooking and weather reports, the use of the Fahrenheit scale is dominant in the United States for these applications. The nominal boiling and freezing temperatures of water were originally taken as the two calibration points for linear temperature scales; 100° and 0° are those respective temperatures in the Celsius scale, and 212° and +32° are boiling and freezing in the Fahrenheit scale. It is easy to derive a conversion formula between °F and °C: () °C=0.55556(°F−32).
Thermal and electrical properties of soils
Published in Hsai-Yang Fang, John L. Daniels, Introductory Geotechnical Engineering, 2017
Hsai-Yang Fang, John L. Daniels
1 Temperature: Temperature is a measure of the internal motion of an object’s constituent molecules. The greater the motion, the greater the internal energy and the higher the temperature. There are three commonly used temperature scales, namely Fahrenheit (°F), Centigrade (°C), and Absolute or Kelvin (°K). On the Fahrenheit scale, the freezing point of pure water is 32°F, and boiling point is 212°F. The Centigrade scale is fixed at 0°C for the freezing point of pure water, and 100°C for the boiling point. The Kelvin or Absolute scale is similar to the Centigrade scale in that the divisions on the scale are the same size, but the zero on the Kelvin or Absolute scale is −273°C, and the boiling point of water is 373°K.
Introduction to Energy, Heat and Thermodynamics
Published in S. Bobby Rauf, Thermodynamics Made Simple for Energy Engineers, 2021
The universal symbol for temperature is: T. The unit for temperature, in the SI, or metric, realm is °C or degrees Celsius. In the Celsius temperature scale system, 0°C represents the freezing point of water. The unit for temperature, in the US, or imperial, realm is °F or degrees Fahrenheit. On the Fahrenheit temperature scale system, 32°F or degrees Fahrenheit represents the freezing point of water. The formulas used for conversion of temperature from metric to US realm, and vice versa, are as follows:
Flow Boiling and Heat Transfer of N-heptane Flow in a Microtube Heated by Concurrent Microflame
Published in Combustion Science and Technology, 2023
Muhammad Tahir Rashid, Junwei Li, Xinjian Chen, Ningfei Wang
The minimum temperature scale is set to the boiling point of n-heptane liquid to locate the interface position. The infrared images with temperature scale, wall temperature distribution, and temperature gradient at different fuel flow rates are shown in Figure 6(a) to (c). At Qf = 5 µl/min, the maximum wall temperature is 1050 K and a steady flame is observed. A similar type of result was confirmed by Chen et al. (Chen et al. 2009). However, they did not report the thermal gradient for high fuel flow rate. At Qf = 70 µl/min the maximum wall temperature is 890 K (Figure 6(a)) because the main reaction at the tube exit is disturbed due to the decomposition of liquid droplets in the flame plume. It can be inferred from this finding that high temperatures at the tube surface are observed at low fuel flow rates due to steady flame at the exit of the tube and complete combustion of liquid n-heptane. The wall temperature decreases at high fuel flow rates, which is attributed to the fact that the reaction zone is away from the exit of the tube.
History of ‘temperature’: maturation of a measurement concept
Published in Annals of Science, 2020
‘Temperature’ is a concept of measurement, and such concepts are of different types.2 The measurement values might be merely nominal, as when we assign bodies into one group we name ‘hot’ or another we name ‘cold’. Within each group we could add an ordinal ranking, using names, such as ‘warm’, ‘hot’, and ‘very hot’, or using numerals, such 1 to 10. But even when numerals indicate an order, we might not be able to meaningfully use them as numbers in calculations. Measurements that are cardinal and not just ordinal can be used in arithmetical operations but maybe not all such operations. An interval scale, such as today’s Fahrenheit temperature scale, allows sums and differences – but not ratios – to be meaningfully calculated. The interval between 10°F and 15°F is the same as the interval between 210°F and 215°F, but water at 15°F is not 50% hotter than water at 10°F. The Kelvin temperature scale is a ratio scale and does allow such percentage comparisons. It also allows an absolute zero, where a measurement of 0 indicates an absence of the measured property. The history of ‘temperature’ is a case study in how increasingly advanced measurement categories can also be chronological stages. This maturation has philosophical implications for what it means to say a concept changes.
Surface grown copper nanowires for improved cooling efficiency
Published in Cogent Engineering, 2018
Anagi M. Balachandra, A.G.N.D. Darsanasiri, Iman Harsini, Parviz Soroushian, Martin G. Bakker
Reduction of copper hydroxide into copper nanowires was found to produce porous nanowires (with reduced thermal conductivity). Post-heat treatment (annealing) was, thus, necessary to improve the structure and properties of the nanowires. Annealing can reduce voids by various diffusion phenomena, and can also remove crystalline defects. Annealing is generally accomplished at temperatures greater than half the melting point on the absolute temperature scale. For example, bulk copper melts at 1083°C; hence, annealing of bulk copper is generally performed at temperatures greater than 405°C (678°K or 761°F). In order to accelerate the process, it is common to anneal bulk copper at about 700 to 800°C. Nanostructures of copper generally have lower melt points than bulk copper; their annealing would, thus, occur at somewhat lower temperatures than bulk copper. Annealing needs to be performed in an inert environment or under hydrogen in order to prevent possible oxidation of nanostructures during annealing. After some trial-and-adjustment steps for identifying a viable anneal temperature and duration, we selected exposure to 350°C for 1 h (in vacuum) as the preferred condition for annealing the reduced copper nanowire structures.