Body temperature variation

The thermal parameters for comfort should be relatively uniform both spatially and temporally. Variations in heat flow from the body make the physiological temperature regulation more difficult. Nonuniform thermal conditions can lead to nonuniform skin temperatures. The active elements of the regulatory system may need to make more adjustments and work harder in order to keep thermal skin and body temperatures stable. To avoid discomfort from environmental nonuniformities, the temperature difference between feet and head should be less than about 3 °C (Fig. 5.9) and the mean surface temperature or radiant difference from one side of the body to the other should not he greater then about 10 °C. 

FIGURE 3.3. Circadian Variations in Errors Made by Process Workers Compared with Body Temperature Changes (adapted from Monk and Embrey, 1981). 

Fig. 3.21 Example of temperature variation as measured by MIMOS II temperature sensors on MER (i) inside the rover body at MIMOS electronics board (black curve), (ii) outside the rover, at the MIMOS II SH (green and red curves), which is at ambient Martian temperature (a) inside the sensor-head, at the reference absorber position (green), (b) outside the SH at the sample s contact plate (red). Temperatures at the two SH positions are nearly identical (difference less than 2 K). During data transmission between the rover and the Earth (or the relay satellite in Mars orbit) the instrument is switched off resulting in immediate small but noticeable temperature changes (see figure above)...

Most metalworking fluids are buffered at about pH 9.0-9.5. Any biocide used must have long-term stability and be efficacious at these pH ranges. In addition to this, a degree of thermal stability is desirable. The main body of diluted metalworking fluid will maintain at a relatively constant temperature, usually about the ambient temperature. The product concentrate may be subject to significant temperature variation depending on how it is stored and the part of the world it is destined for. 

The variation of reaction rate with temperature follows the Arrhenius equation, which we have used to study the rate of chemical reactions in the interstellar medium ISM (Section 5.4, Equation 5.9), and can be applied to the liquid phase or reactions occurring on surfaces. Even the smallest increases in temperature can have a marked effect on the rate constants, as can be seen in the increased rate of chemical reactions at body temperature over room temperature. Considering a reaction activation energy that is of the order of a bond energy, namely 100 kJ mol-1, the ratio of the rate constants at 310 K and 298 K is given by ... 

Variation of temperature is usually not an issue for solid oral dosage forms, since experiments are always conducted at body temperature (37°C). For dosage forms applied on the skin, this can be a further consideration e.g., drug-release testing of transdermal products is typically performed at the average temperature of body surface 32°C (5). 

Table 6.4. Temperature variation of the two- and three-body moments of the spectral function for the H2-Ar-Ar complex the superscripts (12) and (122) stand for H2-Ar and H2-Ar-Ar M(T) is actually the sum of and M(122)".

Theory suggests that ternary moments vary substantially with temperature even sign changes occur with modest temperature variations. This fact offers intriguing possibilities for an experimental separation of the pairwise-additive and the irreducible three-body effects and, perhaps, for a critical search for irreducible ternary contributions. 

This example is motivated by a natural-convection problem (Fig. 3.13) where the body-force term is caused by slight density variations (often caused by temperature variations). Using the so-called Boussinesq approximation, the flow may be considered incompressible, but with the buoyant forces depending on slight density variations. 

In the 1950s, a more evidence-based approach to antipsychotic drug (AP) therapy was undertaken when structural variations of antihistamines were produced by a French scientist (Paul Charpentier), in order to make use of the unwanted sedative side effect produced by these drugs. Initially used to lower body temperature in patients undergoing cardiac surgery, chlorpromazine (Fig. II) was the first drug with antipsychotic properties successfully used in clinical trials [3],... 

Figure 7 Central dimensionless temperature variation with dimensionless temperature for a number of bodies, with negligible surface resistance6...

When a parcel of air in the atmosphere is moved rapidly from an equilibrium condition and its tendency to come back to its undisturbed position is noted, then we term the atmosphere as statically stable. The movement of the packet is considered as impulsive, to preclude any heat transfer from the parcel to the ambience. This tendency of static stability- when exists, is due to the buoyancy force caused by the density differential due to temperature variation with height and such body force acts upon the displaced air-parcel. 

To understand this principle, consider two examples (1) the natural time-window for sleep readiness, and (2) the natural time-window for hallucinatory activity. These are important to recognize if we wish either to promote sleep and/or to reduce hallucinosis. Some people suppose that they can fall asleep at any time, others that they can fall asleep only at one particular time. Both groups are wrong. Despite wide individual variation in sleep proneness—as measured by the multiple sleep latency test—there are both windows of opportunity (the mid to late afternoon) and forbidden zones (the mid evening) for sleep that affect all of us. I am sleepy now at 4 15 p.m., but four hours from now (at 8 15 P.M.), I won t be sleepy at all Both of these probabilities depend upon the circadian curves of body temperature. The way in which the circadian rhythm may interact with AIM so as to produce these effects is shown in figure 10.2. 

The coefficient of expansion of liquids is a more complicated function of the temperature than that of sohd bodies. The linear equation is practically never sufficient to represent the temperature variation. In general it is necessary to resort to a three-constant equation ... 

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