Thermistor Type Research Articles

Diurnal Temperature Change in the Atmosphere between 30 and 60 km Over White Sands Missile Range

Abstract Diurnal temperature variations between 30 and 60 km have been determined in a series of eleven meteorological rocket soundings from 0400 MST 7 February 1964 through 0205 MST 8 February 1964 over White Sands Missile Range, New Mexico. The soundings were spaced at 2-hour intervals and temperatures were measured with thermistor type instrumentation suspended on a parachute. Minimum temperatures were recorded near 0400 to 0600 MST and maximum temperatures occurred about 1400 MST. The temperature range decreased from near 20C at 55 km to 15C at 45 km and to near 5C at 35 km. Significant non-diurnal heating was also present. Additional sets of temperature soundings made at 1400 and 1600 MST on 21 November 1964 and 0400 and 0600 MST on the 22nd over White Sands Missile Range were available for comparison. These soundings indicated a day to night variation of 15C from 63 km down to 55 km with marked dampening of variation thereafter. The November soundings may not represent the entire diurnal range since...

Computation of the basic parameters for a telescope of a radiation pyrometer with a thermistor

Laboratory tests of an experimental model pyrometer using a thermistor type TSh-1 agree well with the calculated values. The above technique of preliminary calculation of the telescope's basic characteristics can be recommended for designing radiation pyrometers with different thermistors.

A thermistor thermometer which reads to the nearest 0.01° C in the field

The suitability of some types of thermistors for measuring temperature with high precision has been investigated. Their ageing, short-term variations of resistance at 0° C, and power dissipation have been tested.A thermistor thermometer suitable for use in the field and giving high precision is described. It compensates for resistance of the leads to the probe, and is automatically compensated for changes in temperature.The construction of a temperature probe using a Western Electric 15 A thermistor is presented and its thermal lag is tested. The effect of introducing manganin wires to reduce heat flow along the wires to the probe is investigated.Some applications of the method are briefly described.

RELATION BETWEEN THE AIR TEMPERATURE DISTRIBUTION AND TEH DENSITY OF HOUSES IN SMALL CITIES IN JAPAN

Temperature observations were done at Ogaki city (pop. 75, 000) in Nobi Plain in Central Honshu and at Kumagaya city (pop. 94, 000) in Kanto Plain. Both of them are located in the middle of the flat alluvial plains and surrounded by extensive paddies. The greater parts of their built-up areas are occuppied by one or two story wooden houses. There are only a few tall concrete buildings in their central areas. Their main roads are paved with asphalt and concrete. Typical distribution patterns of city temperature were observed as were shown in the following figures. The observation were done using the elctric thermometers of thermistor type which we made. The thermometers was mounted on the front bumper of an automobile at about two meters above the ground. Several hundreds observations were made using a technique of moving observation at both cities. At the same times, about ten quick-winding thermographs of our types were installed in and around cities. Fig. 4 shows an isopleth of the temperature variation in thirty minuites intervals at a calm day in Ogaki. The densely populated areas show small variations and the changes occur a little later than the countrysides. Figs. 1, 2, and 3 show typical distribution patterns of temperature in Ogaki at different weather conditions. The pattern of the isotherm distribution shows a strong similarity with the distribution of house density in the city as is shown in fig. 1; Higher temperatures were observed at densely built-up areas, and big temperature-gradients were recognized at the surroundings of the cities. Also temperatures on paved roads seemed to be warmer than those on unpaved roads. Relations between temperature distribution and house density of 200 m square were analyzed on both cities, We could find that 10% increase in house density corresponded to 0.2-0.3°C temperature increase as were shown in Fig. 5. However, the -areas covered by two story houses had 0.2-0.4°C higher temperatures than other areas. These values seemed to be effected by weather conditions remarkably, especially by wind speed. When wind is strong, the values of temperature increase decreases strongly.

A Methane-Conversion Detector for Gas Chromatography

DETECTORS most commonly found in gas chromatographic instruments involve the use of thermal conductivity cells. Such cells, particularly those of the thermistor type, decrease in sensitivity with increasing temperature. Since it is necessary sometimes to heat the cell to prevent condensation effects of high-boiling materials leaving the chromato-graphic column, new approaches to this problem were sought. Martin and Smart1 were successful in improving the sensitivity by converting the resolved compounds as they emerged from the chromatographic column into carbon dioxide and water, and detecting the carbon dioxide by means of an infra-red gas analyser. This procedure was repeated by Green2 using a thermal conductivity cell to measure the carbon dioxide; however, loss of resolution and band spreading detracted from the increased sensitivity obtained. Green improved this technique by passing the water formed in the combustion process through a hot tube containing iron powder, thereby producing hydrogen, which was detected in the thermal conductivity cell. Nitrogen was the carrier gas.

Direct Experimental Comparison of Several Surface Temperature Measuring Devices

A copper cylinder was constructed and to it four layers of oaktanned leather were applied. The thermal gradient through the leather was measured by means of thermocouples on the cylinder and between the layers of leather. By suitable extrapolation of this gradient the temperature of the outside leather surface was determined accurately and constituted the standard surface temperature to which the readings of the surface temperature measuring devices were compared. Several types of surface temperature measuring devices were compared and evaluated on the basis of: (1) accuracy as determined by agreement with the standard surface temperature, (2) adaptability to use in a variety of experimentally produced environmental conditions similar to naturally occurring environmental conditions. It was concluded that: (1) The radiometric type of skin thermometer was the most dependably accurate instrument of those tested, although requiring corrections when used in ``sunlight.'' (2) Under normal conditions, the #40 gauge bare wire thermocouple was of the same order of accuracy as the radiometer and was only slightly affected by environmental changes. The accuracy of the coarser bare wire thermocouple was considerably more impaired by such changes. The thermocouple glued to the surface, or embedded in solder and taped to the surface, or mounted on copper mesh and tied to the surface was less accurate than the bare wire thermocouple. In general, increasing the effective mass of the thermocouple decreased the accuracy of the instrument under normal conditions as well as under the changed environmental conditions. (3) The Dermalor resistance thermometer was next in order. Errors were not greater than two percent under certain conditions but increased to four or five percent during radiation. (4) The errors in the disk thermistor readings ranged from −1.2°C to −1.9°C under the conditions studied. The accuracy of this instrument could be increased by calibration in situ against a radiometer. However, this would not obviate the error produced by infra-red radiation, for instance. This error amounted to −0.7°C. Other types of thermistors having much smaller contact surfaces are available and it is reasonable to expect that these instruments would yield readings as accurate as those of a thermocouple. However, they too would be subject to the errors exhibited by thermocouples or any other small instruments in actual contact with the surface. The feasibility of employing a thermistor as a micro-radiometer is under consideration. It presents special advantages to use in this manner in that thermistors can be constructed with a rapid response time, and as they have a high resistance they are particularly well adapted for electronic recording. (5) The Roll and Mold pyrometers were entirely unsuited to this measurement in the temperature range studied, showing errors of from 3°C to 7°C depending upon the experimental conditions. (6) Mercury-in-glass thermometers were unsuited to this type of temperature measurement because of the long contact time required which affects the temperature itself, and because of the marked impairment of their accuracy by environmental changes.