Heat data

Alimed, M., Fisher, El. G., and Janeshek, A. M., Reaetion Kineties from Self-heat Data Correetion for the Depletion of Sample, Proeeeding of the Int., Symp. on Runaway Reaetions, AIChE/ CCPS, Boston, MA, Mareh 7-9, 1989. 

Data from ref [31] the elastic constants were measured by the pulse-echo technique j3 was determined from low-temperature specific heat data. 

With current computer technology there are several commercial programs available (as well as personal and private) that perform tray-to-tray stepwise calculations up or dovm a column, using the latest vapor pressure, K-val-ues, and heat data for the components. This then provides an accurate analysis at each tray (liquid and vapor ancJy-sis) and also the heat duty of the bottoms reboiler and overhead total or partial condenser. 

To accommodate the step-by-step, recycling and checking for convergences requires input of vapor pressure relationships (such as Wilson s, Renon s, etc.) through the previously determined constants, latent heat of vaporization data (equations) for each component (or enthalpy of liquid and vapor), specific heat data per component, and possibly special solubility or Henry s Law deviations when the system indicates. 

Pressure drops from Dowtherm A heat transfer media flowing in pipes may be calculated from Figure 10-137. The effective lengths of fittings, etc., are shown in Chapter 2 of Volume 1. The vapor flow can be determined from the latent heat data and the condensate flow. With a liquid system, the liquid flow can be determined using the specific heat data. 

Standard heat data are usually compiled at 298 K, and to calculate the heat of reaction at an arbitrary temperature, the temperature dependency of enthalpies of reaction species have to be considered. These are generally dependent on temperature as follows... 

Other constants of the hydrogen molecule obtained from our data are the lowest resonance potential = 11.61 volts the frequency of infinitesimal vibration co0 in the normal state = 4260.cm. 1, which is in fair agreement with the value 4880.cm. 1, obtained by Kemble and Van Vleck5 from specific heat data and the value of x< >o (coefficient of n2) for the normal state = 112.5. cm."1. 

Enthalpy can be calculated from specific and latent heat data see Section 3.5. 

Another approach to relating the hardness to atomic parameters is that of Grimvall and Thiessen (1986) in which hardness is related to vibrational energies. Their theory is slightly modified here by using vibrational energy densities instead of the energies themselves. Specific heat data measure the excitation... 

In Table 12.1, the contributions to the heat capacity Csp of the addendum are shown specific heat data references are reported in ref. [20], A factor 1/3 was attributed to the heat capacity contribution of the elements linking the crystal to the frame [15], Note that the electron heat capacity of the NTD Ge 31 sensor was derived from the electron... 

The estimated heat capacities of bolometer components are shown in Table 15.3 (specific heat data references are in [80]). 

TSR 15). The data (Tables IV-VI) suggest that this instrument provides a satisfactory method for measuring heat release, even in the horizontal mode. Furthermore, it can differentiate between those materials which are prone to release much heat rapidly and those which perform much better in terms of heat release. The reliability of smoke data is, in principle, lower than that of heat data. In order to establish some criteria, the Tables include SmkFct values at 5 min (in MW/m2), which will be compared with SmkFct and SmkPar values for the same materials tested in the Cone and with values of specific maximum smoke density measured in the NBS smoke chamber. 

No thermodynamic signature at Tg is evident in specific heat data at equilibrium, but a peak is observed under nonequilibrium conditions and is often taken as the definition of the glass transition. Unfortunately, this nonequilibrium peak cannot be addressed within the LCT of glass formation. We strictly avoid a discussion of the specific heat, given the complications of interpreting these data for polymer materials and the omission of the important vibrational component in the LCT treatment. 

For non-magnetic actinide metals, specific heat data have been employed very usefully to corroborate 5 f localization starting with Am, as indicated by the sudden drop in y values (ypu 12 mJ/mol K, yAm 2 mJ/mol K ). It allowed also the discovery of superconductivity in Pa and Am metals ... 

Figure 15 displays specific heat data for itinerant antiferromagnetic Nplr2 ° (Tn = 7 K) while results for NpSn3 ° are presented in Fig. 2, showing the BCS-like specific heat anomaly the entropy change at the transition is almost 0. In the case of Np Ir2, the saturation is less clear bad fitting below Tn is attributed to second phase contamination. 

The transport of heat in metallic materials depends on both electronic transport and lattice vibrations, phonon transport. A decrease in thermal conductivity at the transition temperature is identified with the reduced number of charge carriers as the superconducting electrons do not carry thermal energy. The specific heat and thermal conductivity data are important to determine the contribution of charge carriers to the superconductivity. The interpretation of the linear dependence of the specific heat data on temperature in terms of defects of the material suggests care in interpreting the thermal conductivity results to be described. 

Heat Effects — Examples of the Use of Heat Data for Estimating Heat Effects in Explosives and Explosions. 

To illustrate the use of the heat data in the preceeding section for estimating thermal explosion parameters, let us determine the critical thickness of a semi-infinite slab of Tetryl kept at 445°K. From Ref (2) we take E = 35000 cal/mole and Z = 1013sec . Substituting these values in eqn (3) and then into eqns (1) and (2) gives ... 

For simplicity, a systematic classification of solid surfaces by heat of immersion values in a single liquid is desirable. Il in (53) predicted on theoretical grounds a decrease in the heat of wetting with increase in the size of the cation in salts or oxides. However, Il in and Kiselev (54) found that the decrease in the heat of immersion from SrSO< to PbS04 to BaS04 predicted by theory is not observed. Heat data for the immersion of a variety of solids in water are listed in Table VII. Here, too, the changes in heat values are not systematic. 

Dowden and Reynolds (49,50) in further experimental work on the hydrogenation of benzene and styrene with nickel-copper alloys as catalysts, found a similar dependence. The specific activities of the nickel-copper alloy catalysts decreased with increasing copper content to a negligible value at 60% copper and 30-40% copper for benzene and styrene, respectively. Low-temperature specific heat data indicated a sharp fall (1) in the energy density of electron levels N(E) at the Fermi surface, where the d-band of nickel becomes filled at 60 % copper, and (2) from nickel to the binary alloy 80 nickel -)- 20 iron. Further work by these authors (50) on styrene hydrogenation with nickel-iron alloy... 

Considerable variation exists m the reported specific heat data. The following appear to be representative ... 

Since the compressibility is proportional to the pressure derivative of the volume, any experiment that establishes the P-V-T relation of a gas with sufficient accuracy also yields data for the isothermal compressibility. For obtaining the adiabatic compressibility from the P-V-T relation, some additional information is necessary see section (c). Tor instance specific heat data in the perfect gas slate of the substance considered. A more direct way of determining ihe adiabatic compressibility is by measuring the speed of sound i1. the two quantities being related by... 

From the last column of the above table and the specific heat data, the difference in sensible heat between products and reactants is ... 

Specific Heat. Specific heat data are available over a wide temp range (Refs 6 55). The values at 0, 40 and 80° are 0.309, 0.345 and 0.374cal/g/°C, respectively (Ref 6). Rouse (Ref 56) quotes a value of 0.25cal/deg/g Lenchitz and coworkers (Ref 41) have measured it from 10 to 300°K. Some of these data (see footnote in Ref 41) are tabulated below. The specific heat at constant volume has been measured (Ref 31), and found to be ca 30% less than that at constant pressure... 

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