Thermometer Using

The numbers 1.8 and 32 are exact Hence they do not limit the number of significant figures in a temperature conversion that limit is determined only by the precision of the thermometer used to measure temperature. 

Since, from the conditions of the experiment, it was found that the thermometer used would not have been affected if a change... 

These fixed points are used to calibrate a different kind of thermometer that is easier to use than a gas thermometer. Over the temperature range from 13.8033 to 1234.93 °A (or K), which is the temperature interval most commonly encountered, the thermometer used for ITS-90 is a platinum resistance thermometer. In this thermometer, the resistance of a specially wound coil of platinum wire is measured and related to temperature. More specifically, temperatures are expressed in terms of W(T9o), the ratio of the resistance R(Ttriple point of water R (273.16 K), as given in equation (1.11)... 

The type of thermometer used to interpolate between the reference points depends on the temperature interval. 

The deviation function AW Too) is obtained as a function of r90 for various temperature intervals by calibration of the platinum resistance thermometer, using specified fixed points from Table A2.1. The form of the AW(Too) function is dependent on the temperature range in which the thermometer is being calibrated. For example, in the temperature subrange from 234.3156 to 302.9146 K, the form of the deviation function is... 

The submitters recommend calibrating the thermometer to ca. -78°C when immersed in a dry ice-acetone bath. The thermometer used for these runs (Catalog Z11,011-6) was purchased from Aldrich Chemical Company, Inc. Three different thermometers (two Fisher 15-035 and one Ertco X7048) were found that read from -86°C to -96°C when immersed In a dry ice-acetone bathl The checkers used a digital thermometer, model 450-ATT, purchased from OMEGA Engineering, Inc., Stamford, CT 05907. 

A cryogenic sensor is, for example, a thermometer used around a fixed temperature where it shows a high sensitivity. It does not usually need a calibration. The realization technology of sensors often differs from that of the corresponding thermometers. 

In a cryogenic experiment, one or several detectors are used for a definite goal for which they have been optimized. For example, in CUORE experiment described in Section 16.5, the sensors are the Ge thermistors, i.e. thermometers used in a small temperature range (around 10 mK). One detector is a bolometer made up of an absorber and a Ge sensor. The experiment is the array of 1000 bolometers arranged in anticoincidence circuits for the detection of the neutrinoless double-beta decay. Note that the sensors, if calibrated, could be used, as well, as very low-temperature thermometers. Also the array of bolometers can be considered a single large detector and used for different purposes as the detection of solar axions or dark matter. 

SAQ 1.1 A temperature is measured with the same platinum-resistance thermometer used in Worked Example 1.1, and a resistance R = 11.4 x 10 4 2 determined. What is the temperature ... 

G. Beheim, Fibre-optic thermometer using semiconductor etalon sensor, Elec. Lett. 22(5), 238-239 (1986). 

Z. Y. Zhang, K. T. V. Grattan, and A. W. Palmer, Sensitive fibre optic thermometer using Cr LiSAF fluorescence for bio-medical sensing applications, Proc. 8th Optical Fiber Sensors Conf., Monterey, California, pp. 93-96, IEEE, New York (1992). 

Figure 12.10. Fluorescence lifetime thermometer used in the treatment of benign prostatic hyperplasia. (From Ref. 51.)...

Thermometer Used (electronic) Calibration Number 11 Expiration Date ... 

If the temperature of 1 mL of air at 1 atm and 0°C is raised to 100°C at the same pressure, the volume becomes 1.3671 mL. Calculate the value of absolute zero for a thermometer using air, assuming that the pressure-volume product is linear with absolute temperature even at 1 atm. Compare your result with the ice-point temperature in Table 2.3. 

Beckmann, E. Chem. Ber. 1886, 89, 988. Ernst Otto Beckmann (1853—1923) was bom in Solingen, Germany. He studied chemistry and pharmacy at Leipzig. In addition to the Beckmann rearrangement of oximes to amides, his name is associated with the Beckmann thermometer, used to measure freezing and hoihng point depressions. Mazur, R. H. J. Org. Chem. 1961,26, 1289. 

It is possible to check the calibration of a pipet, flask, or buret. The process involves weighing with a calibrated analytical balance. The volume of water (temperature noted) delivered or contained by the glassware is weighed. Then the analyst converts this weight to volume (using the density of water at the temperature noted), corrects the result to 20°C (the usual temperature of the factory calibration), and compares it to the factory calibration. If the difference is not tolerable, the piece of glassware is either not used for accurate work or a correction factor is applied. It should be pointed out that the thermometers used must be properly calibrated and that the timer used to measure the delivery time for the burets and pipets must also be calibrated. 

Temperature °C (SI unit)3 Used in the standard uncertainty of V Certificate of calibration of thermometer used to monitor laboratory temperature... 

Thermometers, use in apparatus with interchangeable ground glass joints, 213f, 2271... 

It is important to consider what happens when the substance or property employed is changed. For example, for a liquid in glass thermometer (using the Centigrade scale) ... 

If linear interpolation is applied in this way then two thermometers using different thermometric properties brought into contact with the same heat reservoir will give identical readings only at the fixed points. 

For accuracy the thermometer should be capable of being read to a tenth of a degree Celsius. The usual thermometer used is that shown in the photograph that measures accurately between -10° and 110°C. When reading the thermometer always ensure that your eye is at the same level as the liquid meniscus in the thermometer to ensure there are no parallax effects. The meniscus is the way that the liquid curves at the edges of the capillary in which the liquid is held in the thermometer. 

The Beckmann thermometer used with the bomb calorimeter should be calibrated for the normal depth of immersion with which it is used. To cover the normal range of laboratory temperatures, this calibration should be obtained for three settings of the zero on the scale, convenient values being 10, 15, and 20°C. Such a series of calibrations allows automatically for emergent stem corrections and variations in the value of the degree on the thermometer scale with different quantities of mercury in the bulb, in addition to those arising from inherent variations in the diameter of the capillary bore. 

Liquid-in-glass thermometers used mercury or alcohol as the liquid that expands as it gets warmer. Most countries mandate the removal of any mercury-filled devices due to its extreme toxicity, but alcohol and other fillings are still used. The expansion rate is linear with temperature and can be accurately calibrated. Bimetallic thermometers bond two dissimilar metals with different coefficients of expansion to produce the bimetallic element in thermometers, temperature switches, and thermostats. Filled System Thermometers can be filled with either liquid or vapor. Liquid-filled units are the most popular although they require compensation for the weight of the liquid head and for capillary length. Vapor-filled elements cannot be used if the operating temperature crosses the vapor/liquid point. 

Routine measurements of temperature are done with a thermometer. Thermometers found in chemistry laboratories may use either mercury or a colored fluid as the liquid, and degrees Celsius (°C) as the units of measurement. The fixed reference points on this scale are the freezing point of water, 0°C, and the boiling point of water, 100°C. Between these two reference points, the scale is divided into 100 units, with each unit equal to 1°C. Temperature can be estimated to 0.1°C. Other thermometers use either the Fahrenheit (°F) or the Kelvin (K) temperature scale and use the same reference points, that is, the freezing and boiling points of water. Conversion between the scales can be accomplished using the formulas below. 

Attach the capillary tube to the thermometer, using a narrow rubber band near the top of the tube. Be certain to align the tip of the thermometer with the tip of the capillary tube (Fig. 19.4). 

Fig. 2.29 Bimetal thermometers use two metals of different expansion to create spiral thermometers.

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