Cold sensors

Maltitol is a sugar alcohol like sorbitol, mannitol, and xylitol, but it is a larger molecule. Unlike those other sugar alcohols, and menthol, maltitol does not stimulate the cold sensors in the skin, so it does not feel cool in the mouth. 

Between these two extremes arc encompassed a Pandora s Box of myriad contrivances such as counters, light-controlled switches, moisture sensors, heat and cold sensors, capacitively operated relays, and uncountable combination.s of all of these and many more. 

Nishiyama, S., Umemura, T., Nara, T., Homma, M. and Kawagishi, 1. (1999). Conversion of a bacterial warm sensor to a cold sensor by methylation of a single residue in the presence of an attractant. Mol. Microbiol. 32, 357-365. 

Melt too cold] sensor error/control system error/lack temperature confirmation via hand-held pyrometer or laser sensor/cylinder too cold/screw rpm too slow/ back pressure too low/insufficient plasticizing capacity of machine/jnozzle too cold] /heating band fault/excessive flow length in mold. 

EGR can seriously degrade engine performance, especially at idle, under load at low speed, and during cold start. Control of the amount of EGR during these phases can be accompHshed by the same electronic computer controller used in the closed loop oxygen sensor TWC system. Thus the desired NO reduction is achieved while at the same time retaining good driveabiUty. 

It has been suggested that the ribosome might act as the sensor for the cold shock response [94,99], and it was postulated that the physiological signal for the induction of the cold shock response may be inhibition of initiation of... 

The major requirement for a reliable hydrogen sensor operation in the fuel cell environment is in 100% condensing humidity Most of the fuel cells have abundant humidity and the sensor needs to operate continuously in humid environments. In some cases, the hydrogen sensor can also be operated at very low temperatures (as low as —40°C). The fuel cells regularly have a cold start, when operated from a very low ambient temperature the sensor needs to attain ambient temperature quickly (<30 s) and continue operation well below ambient temperature before the fuel cell itself reaches the ambient temperature. 

Most solid-state sensors are heated to well above 100°C and can operate in the "cold start" condition in a fuel cell. Another important performance parameter for a hydrogen sensor in a fuel cell is its resistance to water entry. Most fuel cells have excess of liquids including water during operation. It is highly possible that water will splash or penetrate into the hydrogen sensor mounted in the ventilation or outlet of a fuel cell. Hydrophobic... 

G. Walker Miniature Refrigerators for Cryogenic Sensors and Cold Electronics Clarendon Press, Oxford (1989)... 

Many Asian washing machines operate exclusively with cold water, although the cold-water temperature is not necessarily the 10-15 °C that can be expected in Europe. It may well be considerably higher. Therefore such machines are not fitted with a temperature sensor. Another machine type, particularly common in the USA, has a cold-water connection and an additional hot water connection but... 

A thermopile sensor generates an output voltage that depends on the temperature difference between its hot and cold contacts. For infrared temperature measurement, the hot contacts are normally thermally insulated and placed on a thin membrane, whereas the cold contacts are thermally connected to the metal housing. Infrared radiation, which is absorbed by the hot contacts of the thermopile, causes a temperature difference between hot and cold contacts. The resulting output voltage is a measure for the temperature difference between radiation source and cold contacts of the thermopile sensor. It is therefore necessary to measure also the temperature of the cold contacts by an additional ambient temperature sensor in order to determine the temperature of the radiation source. 

Fig. 13.23 (a) Transmission power of microtoroid resonator near the condition of critical coupling (inset shows the MNF/microtoroid sensor), (b) Single photon counting events C(t) as a function of time t after the release of the cold atom cloud at t 0. Reprinted from Ref. 48 with permission. 2008 Nature Publishing Group... 

Thermopiles are considered temperature sensors and are fabricated incorporating a number of thermocouples. Each thermocouple is formed by a couple of different materials (Metall-Metal2, Metal-Semiconductor, Semiconductor-Semiconductor) and responds to a temperature difference localized between the two junctions (cold junction and warm junction ), see fig. 11. One of the two junctions can be considered the reference one. 

A thermopile can also be used as a chemical sensor if one of the two materials is a catalytic metal for a given volatile compound. In this case it is necessary to keep the warm and cold junctions at constant temperature. During absorption of the volatile compound on behalf of the catalytic material the thermoelectric power may change, giving rise to an output voltage which can be related to the concentration of the volatile compound. A typical example is the thermopile as hydrogen sensor, where one of the two materials is palladium, a standard hydrogen catalyzer. 

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