Room reference temperature

Room reference The average of at least five measurements of the air temperature at a height of 1.1 m from the floor and outside the area directly influenced by the device. 

The tracking mode performance of the on-chip digital temperature controller of the differential mixed-signal architecture is shown in Fig. 6.11. The measurement was done at room temperature, and the digital code of the reference temperature of microhotplate 1 was increased in steps of 100 digits. Microhotplates 2 and 3 were switched off during the measurement. The resolution of the digital temperature controller was better than 2 °C. 

Molar enthalpy data for elements and inorganic compounds above room temperature are usually tabulated in the form of the heal content above a reference temperature, usually 298.I5°K = 25" C. They are represented by. Hr - HyK is in ealories/mole. The data are correlated over a range of temperature by empirical equations such as a series of powers of the absolute temperature or such as the following expression adopted by K.K. Kelley (1960) for his extensive compilation of data on inorganic compounds ... 

However, when the reference temperature is much higher than the temperature of interest, as would be the case for estimating the room temperature vapor pressure of a relatively high boiling liquid, the variation of AHv with temperature may introduce a significant error in the vapor pressure. Assuming that AHv varies linearly over the range T to Th... 

Like many other properties (such as the molar volume, Chapter 3 heat capacity, Chapter 4 and surface tension, Chapter 7), the thermal conductivity of an amorphous polymer can be estimated as a function of the temperature if it has been measured or predicted at some reference temperature, usually taken as room temperature (298 5K). For example, van Krevelen [6] plotted the measured values of A,(T)A,(Tg) against the "reduced temperature" T/Tg for... 

The standard state of a substance is its pure form in a defined state of aggregation at a pressure of 1 bar and a specified temperature. It is denoted by the index e.g. s. A// . The conventional reference temperature for the specification of energy functions (enthalpy) is 298.15 K = 25 C (room temperature). 

It will be clear that the direct use of the WLF equation will produce a master curve with either Tg or Tg as its reference temperature To. It may be, however, that the master curve is required at some other temperature (e.g. room temperature). In such a case, it is a relatively simple matter to calculate the constants (Cj and C ) for any chosen reference temperature Tq. 

As currently planned, a number of specimens W M be oxidized at a selected reference temperature and time. Room temperature, four point bend tests allow the development of the two Weibull PIA surface constants within CARES. The material constant related to activation energy is obtained by the regression analysis of room temperature fracture tests of specimens exposed to a variety of temperatures and times. In this regression, data is examined by CARES to determine if the data contains outliers (i.e. data whose normalized residual exceeds the critical value at the luX significance level). The outliers are deleted from the data set prior to computing the activation energy constant. 

The temperature at which absorptivity, hypochromicity, and hwerchromicity values were obtained is given in the Note and T(°C) columns for oligonucleotides and pol3mucleotides, respectively. Absence of temperature data indicates that they were not given in the reference temperature in such cases is usually understood as a room temperature. 

Fig. 7.19. Experimentally determined stress versus temperature hysteresis data for a 1 jjLm. thick A1 film deposited on a relatively thick elastic substrate. The specimen was first heated from room temperature to 300 °C (the data point set marked 1 ), held at that temperature for 30 min., and then subsequently cooled to a minimum temperature before being heated again to 300 °C. This minimum temperature was chosen to be 110, 50, 20 and —10 °C for the four thermal cycles, the heating portions of which are denoted by the numbers 2, 3, 4 and 5, respectively. The specimen was held at 300 °C for 30 min. during each thermal cycle. The as a function of temperature. The solid curves in Figure 7.19 show the response for elastic and plastic deformation implied by (7.75) and (7.76). To denotes the stress-free reference temperature. Experimental data provided by Y. J. Choi, Massachusetts Institute of Technology (2002).

The temperature boundary conditions are defined in accordance with the updated revision of reference temperature from the Slovak hydrometeorological institute (SHMU) and relevant standard STN EN 1991-1-5 NA. A return period of 10000 year is a reasonable choice for this type of evaluation. The lowest annual temperature where chosen as they correspond to the case where the thermal stress is maximized (i.e., largest heat flux at the external walls). An estimation for the ground temperature is consider in accordance with STN EN 1991-1-5 NA for defining the boundary conditions at the bottom of the hermetic zone, considering a simplified but eonservative modeling for the rooms underneath. 

Consider first the temperature distribution to be expected in the vapor above a bath of liquid helium in a cylindrical glass dewar. Here both the dewar wall and the vapor are poor thermal conductors. There is a flow of heat down from the top of the dewar, and a flow of cold gas up from the liquid surface. The flow velocity of the gas increases as its temperature increases. Calculation of the expected temperature distribution is quite difficult. However, one might expect a more or less linear increase in vapor temperature from that of the liquid to a reference temperature of about 80 K, followed by a second uniform increase to room temperature. 

For instance, taking T = 0 to be the lowest possible temperature means that d is the smallest possible volume for the gas. A different scale could take T = 0 to be room temperature, and then d would be the volume of the sample at room temperature, not the smallest possible volume, d can be eliminated by using an absolute scale whereby T = 0 corresponds to the temperature at which V = 0.c can be eliminated (replaced) by invoking some reference temperature, Tq, at which the volume is known to be some value, Vq-... 

The term room temperature is sometimes misused. It was meant to define the temperature in a conditioned room, usually enclosed, such as an office or a work area, e.g., laboratory. The temperature range may vary according to the location, e.g., as narrow as 20—23°C in a measurement laboratory or as wide as 18-25°C in rooms where temperature sensitivity is not as crucial, such as storage hall for general goods. Unless specified, room temperature mentioned in this chapter refers to a temperature range of 18-25°C. 

PEO, which are typical matrices for polymer electrolytes, has been reported to be 10 to 10 s at room temperature, and its temperature dependence obeys the WLF equation [24]. These features are shown in Fig. 5 [11]. The temperature dependence of the inverse of the dielectric relaxation time t(T), owing to the backbone motion of the PPO network polymer, obeys the WLF equation shown in this figure. How small ions migrate in these rubbery media is an interesting question. The percentage change in the conductivity with temperature is comparable with that in the dielectric [11,25] or mechanical relaxation time [16,26,27] of the backbone motion for the PPO-and PEO-based polymer electrolytes, when is used as reference temperature. A typical result is shown in Fig. 6 [26], in which the ratio of ionic conductivity at T, to that at T, o (Tg), and the ratio of mechanical... 

The percent strain limits are arbitrary relative divisions defining the behavior. The above definitions of a brittle and ductile material assume that the reference temperature is room temperature. It is best to refer to ductile behavior and brittle behavior, rather than define materials as ductile or brittle. A material that is brittle at room temperature will be ductile at some elevated temperature, and a material that is ductile at room temperature will exhibit brittle behavior at a low-enough temperature. Ductile and brittle are relative terms. The point is that mechanical properties, particularly for polymers, are highly dependent on temperature. 

However, if the liquid solution contains a noncondensable component, the normalization shown in Equation (13) cannot be applied to that component since a pure, supercritical liquid is a physical impossibility. Sometimes it is convenient to introduce the concept of a pure, hypothetical supercritical liquid and to evaluate its properties by extrapolation provided that the component in question is not excessively above its critical temperature, this concept is useful, as discussed later. We refer to those hypothetical liquids as condensable components whenever they follow the convention of Equation (13). However, for a highly supercritical component (e.g., H2 or N2 at room temperature) the concept of a hypothetical liquid is of little use since the extrapolation of pure-liquid properties in this case is so excessive as to lose physical significance. 

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