Digital thermometer

Q90 Digital thermometers are safer to use in children than glass thermometers. Digital thermometers are cheaper than glass thermometers. 

Callendar-van Dusen Equation. The complexity of the ITS-90 equations, especially for temperatures below 273.16 K, creates an awkward situation. For practical use, the Callendar-van Dusen equation, which was the basis for IPTS-48, is still a very convenient form. This is especially true if one wishes to determine the resistance R of a Pt thermometer digitally under computer control and convert it into a temperature with a reasonably simple algorithm. The general form of the Callendar-van Dusen equation is... 

Liquid crystals are used in displays for a number of products. Early uses included digital thermometers, digital wristwatches, electronic games, and calculators. As the power needed for an LCD display and resolution improved, LCDs came to be used in computer monitors, television sets, car dashboards, and cellphones. 

Mercury thermometers, both for laboratory and clinical use, have been replaced by digital ones. 

An Omega model HH22 type J-K digital thermometer, connected to a type K thermocouple probe inserted directly into the flask, was used to measure the temperature. 

The exactness of a measurement is expressed by its precision. This concept can be explained with an example. Suppose three swimmers are discussing the temperature of a swimming pool. The first dips a finger in the water and says that the temperature is about 24 °C. The second examines an immersed pool thermometer and reports the temperature to be 26 °C. The third swimmer, who has been monitoring daily variations in the pool s temperature, uses a portable precision digital thermometer and reports, According to my precision thermometer, the pool temperature is 25.8 °C. ... 

P 60] The dehydration of 1-hexanol to hexane and of ethanol to ethane were conducted at 155 °C. Heating was accomplished by a heating wire inserted in the micro reactor s top plate. This wire was connected to a potentiostat (0-270 V) temperature was monitored by a digital thermometer with the probe close to the reaction channel. A syringe pump was applied for liquid transport [19]. A flow rate of 3 pi min was applied. The alcohols were purged with nitrogen directly prior to reaction to minimize coke formation. 

To do this, the software must be aware of conditions within the reactor therefore, we shall arrange that it is fed with regular messages from a digital thermometer in contact with the fermenting medium. The thermometer, and any other probes in the vessel, send messages to the software in the form of binary strings, such as ... 

Let us assume that messages from the digital thermometer are tagged with the identifier "00." The rest of the message conveys information about the current temperature, T. Table 9.1 shows how the message sent from the digital probe provides information about reactor conditions. 

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 Fluke 51 K/J digital thermometer with temperature probe is used to monitor internal reaction temperature. 

Shortly thereafter Hajek investigated the related CuCl/2-propylamine-catalyzed addition of tetrachloromethane or ethyltrichloroacetate to styrene (Eq. 11.42) and reported a more modest increase in the reaction rate [60]. The reactions were performed under both microwave and classic heating conditions, and the temperatures in the samples were measured by a quick-response digital thermometer. 

Thermotropic cholesterics have several practical applications, some of which are very widespread. Most of the liquid crystal displays produced use either the twisted nematic (see Figure 7.3) or the supertwisted nematic electrooptical effects.6 The liquid crystal materials used in these cells contain a chiral component (effectively a cholesteric phase) which determines the twisting direction. Cholesteric LCs can also be used for storage displays utilizing the dynamic scattering mode.7 Short-pitch cholesterics with temperature-dependent selective reflection in the visible region show different colors at different temperatures and are used for popular digital thermometers.8... 

Temperature measurement was historically done with a mercury thermometer. Modern instruments have electronic temperature sensors that can be coupled with digital temperature readouts. Digital temperature monitoring also allows the operator to record the observed melting point with the press of a keypad button. Data can be stored within the instrument or transmitted to a computer or laboratory information management system (LIMS). 

A Teflon-coated thermocouple of the J-type attached to an Omega model 650 digital thermometer can be substituted for the immersion thermometer. 

Basic firmware instruments used to measure fundamental physical parameters such as weight, dimension, temperature, and pH Balances, pH meters, digital thermometers, centrifuges, sonicators... 

A. Simple COTS instrument (commercial Balance, pH meter, digital thermometer... 

Automation frequently aids accuracy and/or reproducibility by being more consistent than humans. Non-contact extensometers ensure no unwanted stresses on the test piece and any automatic extensometer will be less subjective than a technician with a ruler. Digital thermometers, load cell balances and many other apparatus introductions have made measurements easier and less prone to operator error. 

The actual temperature of the solution in the vicinity of the working electrode should be measured. It is not wise to assume that the solution temperature equals that of the bath, particularly when using a circulating refrigerated bath, because the temperature of the coolant will rise on passage from the bath to the cell. Low-temperature thermometers can be used in principle, but the almost universal choice is a thermocouple. Many commercial units are available with digital output and control features. The thermocouple junction can be coated with Teflon and inserted directly into the cell. 

Install prepared combustion tube in N2 analyzer. Adjust 45% KOH solution meniscus to calibrating mark in nitrometer with digital readout meter. Record counter reading, / ,. Record syringe temperature, t indicated on special scale thermometer. 

A calibrated digital cooking thermometer is preferable for measuring sample temperature. 

Temperature variations in the instrument are a source of error and electrical power dissipation is limited to avoid the effects of self-heating. This is achieved by means of the four lead system shown in Fig 6.25ft. This minimises any effects of variations in temperature on the resistance RCL of the connections between the RTD and the bridge and is used normally with digital thermometers and data acquisition systems where the sensor non-linearity is corrected within the computer software. 

Fig. 1.28. Cryoscopy cell, (a) Typical dimensions of the lower section are 260-mm height and 20-mm diameter. The thermistor well is about 27 mm. (b) Cooling apparatus for the cryoscopy cell. The cryoscope slips into the jacketed tube. The jacket is evacuated or partially evacuated to control the cooling rate. Electrical readout is achieved with a digital multimeter or commercial electronics for thermistor thermometers.

To indicate the uncertainty in a measurement, the value you record should use all the digits you are sure of, plus one additional digit that you estimate. In reading a mercury thermometer that has a mark for each degree, for example, you could be certain about the digits of the nearest mark—say 25°C—but you would have to estimate between two marks—say 25.3°C. 

Total immersion type low temperature pentane thermometers (Kessler) were used to measure the temperature in the partial immersion mode. The readings are usually 7-8°C higher compared to the actual temperature under our reaction conditions. The temperatures reported here are all corrected by subtracting 7°C from the thermometer readings. The checkers used a Delta MC-20R digital thermometer (Sato Keiryoki Co., Japan). Temperature control is very important to obtain a satisfactory yield. 

Alkylation of 1. To a mixture of the ester 1 (5 g, 25 mmol) and 6% of Aliquat 336 (715 mg, 1.5 mmol) was added t-BuOK (3.3 g, 25 mmol, 1 equiv.) under magnetic stilling over 15 min alkyl bromide (25 mmol, 1 equiv.) was then added slowly. The flask was left under the experimental conditions indicated in Table 1. Finally, the mixture was diluted with ethyl acetate (50 ml) and filtered on Florisil (10 g). The crude products were analysed by GC and characterised by MS and HNMR. 2-Alkylcyclohexanones. A mixture of lithium bromide (1.73 g, 20 mmol), tetrabutylammonium bromide (323 mg, 1 mmol), water (360 mm, 0.36 mL, 20 mmol) and ethyl l-alkyl-2-oxocyclohexanecarboxylate 2 (10 mmol) was placed in a Pyrex tube. The tube was then introduced into a Maxidigest MX 350 Prolabo microwave reactor fitted with a rotational system. Microwave irradiation was carried out for a suitable power and time (Table 2). An approximate final temperature was measured by introducing a digital thermometer at the end of irradiation. The mixture was cooled to ambient temperature. After elution with ethyl acetate (50 mL) and subsequent filtration on Florisil, organic products were analyzed by GC and finally purified by chromatography on silica gel (pentane-ethyl acetate, 95 5). 

To 10 mmoles of potassium carboxylate were added in a Pyrex flask 10 mmol of n-octyl bromide and 1 mmol of tetraalkylammonium salt (Aliquat 336 or Bu4NBr). After shaking, the flask was introduced in the microwave oven (or in an oil bath for control experiments) for the indicated time. The temperature was measured by introducing a Quick digital thermometer in the sample just at the end of each irradiation. Organic products were recovered by a simple elution with 50 mL diethyl ether or methylene chloride and subsequent filtration over... 

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