absolute temperature


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temperature

 [tem´per-ah-chur]
the degree of sensible heat or cold, expressed in terms of a specific scale. See Table of Temperature Equivalents in the Appendices. Body temperature is measured by a clinical thermometer and represents a balance between the heat produced by the body and the heat it loses. Though heat production and heat loss vary with circumstances, the body regulates them, keeping a remarkably constant temperature. An abnormal rise in body temperature is called fever.

Normal Body Temperature. Body temperature is usually measured by a thermometer placed in the mouth, the rectum, or the auditory canal (for tympanic membrane temperature). The normal oral temperature is 37° Celsius (98.6° Fahrenheit); rectally, it is 37.3° Celsius (99.2° Fahrenheit). The tympanic membrane temperature is a direct reflection of the body's core temperature. These values are based on a statistical average. Normal temperature varies somewhat from person to person and at different times in each person. It is usually slightly higher in the evening than in the morning and is also somewhat higher during and immediately after eating, exercise, or emotional excitement. Temperature in infants and young children tends to vary somewhat more than in adults.
Temperature Regulation. To maintain a constant temperature, the body must be able to respond to changes in the temperature of its surroundings. When the outside temperature drops, nerve endings near the skin surface sense the change and communicate it to the hypothalamus. Certain cells of the hypothalamus then signal for an increase in the body's heat production. This heat is conducted to the blood and distributed throughout the body. At the same time, the body acts to conserve its heat. The arterioles constrict so that less blood will flow near the body's surface. The skin becomes pale and cold. Sometimes it takes on a bluish color, the result of a color change in the blood, which occurs when the blood, flowing slowly, gives off more of its oxygen than usual. Another signal from the brain stimulates muscular activity, which releases heat. Shivering is a form of this activity—a muscular reflex that produces heat.



When the outside temperature goes up, the body's cooling system is ordered into action. Sweat is released from sweat glands beneath the skin, and as it evaporates, the skin is cooled. Heat is also eliminated by the evaporation of moisture in the lungs. This process is accelerated by panting.

An important regulator of body heat is the peripheral capillary system. The vessels of this system form a network just under the skin. When these vessels dilate, they allow more warm blood from the interior of the body to flow through them, where it is cooled by the surrounding air.
Abnormal Body Temperature. Abnormal temperatures occur when the body's temperature-regulating system is upset by disease or other physical disturbances. fever usually accompanies infection and other disease processes. In most cases when the oral temperature is 37.8°C (100°F) or over, fever is present. Temperatures of 40°C (104°F) or over are common in serious illnesses, although occasionally very high fever accompanies an illness that causes little concern. Temperatures as high as 41.7°C (107°F) or higher sometimes accompany diseases in critical stages. Subnormal temperatures, below 35.6°C (96°F) occur in cases of collapse; see also symptomatic hypothermia.
absolute temperature (T) that reckoned from absolute zero (−273.15°C), expressed on an absolute scale.
basal body temperature (BBT) the temperature of the body under conditions of absolute rest; it has a slight sustained rise during the luteal phase of the menstrual cycle and can be used as an indirect indicator of when ovulation has occurred.
body temperature the temperature of the body of a human or animal; see temperature.
core temperature the temperature of structures deep within the body, as opposed to peripheral temperature such as that of the skin.
critical temperature that below which a gas may be converted to a liquid by increased pressure.
normal temperature the body temperature usually registered by a healthy person, averaging 37°C (98.6°F).
risk for imbalanced body temperature a nursing diagnosis accepted by the North American Nursing Diagnosis Association, defined as a state in which an individual is at risk of failure to maintain body temperature within the normal range.
subnormal temperature temperature below the normal. See also symptomatic hypothermia.

ab·so·lute tem·per·a·ture (T),

temperature reckoned in degrees Kelvin from absolute zero.

ab·so·lute tem·per·a·ture

(T) (ab'sŏ-lūt' tem'pĕr-ă-chŭr)
Temperature reckoned in the Kelvin scale from absolute zero.

absolute temperature

Temperature expressed in the Kelvin scale with absolute zero as 0 kelvin. The magnitude of the kelvin is the same as that of the degree Celsius and any Celsius temperature can be represented as an absolute temperature by degrees C - 273.15. The term ‘degree kelvin’ is no longer used; absolute temperatures are shown in kelvins (WilliamLord Kelvin, British physicist, 1824–1907).
References in periodicals archive ?
The absolute temperature coefficients for the important parameters of the photovoltaic cells at different levels of illumination are presented in Table 1.
Figure 1 shows the drying coefficient variation (k's) with variations of absolute temperature (in Kelvin) for the speeds of drying air under analysis.
3-Disintegration of calcined samples was carried out more quickly due to the dehydration process.NomenculatureE- Activation Energy, kJ mol-1K -Rate Constant, s-1ko- Frequency Factor, s-1n- Reaction OrderQ- Heating Rate, K s-1R- Universal Gas Constant, 8.314 J.mol-1 K-1T- Absolute Temperature, Kx- Fraction Reacted
The absolute temperature is taken to be equal to one.
For weather conditions, minimum absolute temperature, total number of days with temperature below 0[degrees]C, and altitude showed a significant correlation (P = 0.01, P = 0.01, and P [less than or equal to] 0.01, resp.).
The Arctic is now suffering the fastest absolute temperature rises, but temperatures have naturally swung widely in history.
that enables one to evaluate the mean time to failure (MTTF) [tau] from the known applied stress [delta] (not necessarily mechanical); the absolute temperature T, the time constant [[tau].sub.0], the (stress-independent) binding (activation) energy [U.sub.0]; k = 1.3807 x [10.sup.-23]J/[.sup.0]K is Boltzmann's constant, and the factor [gamma] is the material (device) constant that is a measure of the vulnerability of the material to the applied stress and is measured by energy per unit stress, so that the product [gamma][delta] measured in energy units.
The absolute temperature record in Bulgaria was measured in 1916 in the village of Sadovo, near the second largest city of Plovdiv.
"It's going to be hot, and actually the most important thing is that it's going to be humid, and humidity is a bigger factor than the actual absolute temperature as far as heat-related illnesses," said (http://www.indianapolismotorspeedway.com/indy500/news/show/type/news/51749-indianapolis-500-fans-urged-to-take-precautions-against-heat/) Dr.
However, neither the thermocouple nor the microhotplate thermal resistance can be directly calibrated as a temperature sensor by heating the entire chip containing the microhotplate because, unlike the heater resistance which responds to absolute temperature, the thermocouple and the thermal resistance respond to the temperature difference between the microhotplate and the substrate on which it is located.
The distance between any two points in the structure at one temperature will increase or decrease in direct proportion to the product of that distance, the absolute temperature change of the entire body, and a factor unique to the material.
Flexibility and versatility are key attributes of the service offer backed up with depots situated in; Newcastle, Glasgow, Doncaster, Gillingham, Bury St Edmunds, Bristol, Hemel Hempstead and Wrexham along with Absolute Temperature Network partner depots in South Wales and Ireland.