Thermoneutral temperature

The difficulty with this scheme is that birds also use evaporation by panting to cool themselves. If the inlet air is cooled by evaporation, water vapor is also added to the air. The extra moisture in the air makes it more difficult for individual birds to cool themselves, as would still be necessary if the air temperature is not cooled at or below thermoneutral temperatures. In this case, the cooled air can gain heat not only from the birds themselves, but also from hot surfaces of the poultry house. Thus, this scheme of cooling air actually can make matters worse rather than better. 

Very slow, nearly thermoneutral, equilibrium-limited esterification at ambient temperature. 

Figures 4.6—4.8 are the results for the stoichiometric propane-air flame. Figure 4.6 reports the variance of the major species, temperature, and heat release Figure 4.7 reports the major stable propane fragment distribution due to the proceeding reactions and Figure 4.8 shows the radical and formaldehyde distributions—all as a function of a spatial distance through the flame wave. As stated, the total wave thickness is chosen from the point at which one of the reactant mole fractions begins to decay to the point at which the heat release rate begins to taper off sharply. Since the point of initial reactant decay corresponds closely to the initial perceptive rise in temperature, the initial thermoneutral period is quite short. The heat release rate curve would ordinarily drop to zero sharply except that the recombination of the radicals in the burned gas zone contribute some energy. The choice of the position that separates the preheat zone and the reaction zone has been made to account for the slight exothermicity of the fuel attack reactions by radicals which have diffused into...

A small decrease in ambient temperature, below the thermoneutral, results in a decrease in heat loss by reducing the flow of blood to the skin. If this is not sufficient to restore the normal body temperature, specific processes, including shivering, that result in heat generation, are stimulated. 

Figure 25 Effect of temperature on A TR products from 1 mole of n-Cj at thermoneutral conditions (Calculations using HSC Chemistry 4.0 )...

Reaction 8.28 is endothermic and 8.29 exothermic, and the combination is almost thermoneutral (AH 0). Since the combustion temperature is lower than in traditional boiler designs, less NO is emitted, and the ash does not melt and so cannot foul the heat transfer surfaces. 

From my estimates on the thermodynamic properties of peroxy and polyoxide molecules and radicals, we can estimate that the bond dissociation energy of the tetroxide is about 5 kcal. Thus, at room temperature, or even at dry ice temperature, the tetroxide is extremely unstable and should redissociate into the more stable (from a thermodynamic point of view) peroxy radicals. The competing step would be a concerted decomposition into an RO and an R03 (Step 14) radical, which would be uphill by 20 kcal., or else a concerted decomposition into 2 RO radicals and 02 (Step 14 ). The latter is almost thermoneutral. If we take the current data at face value, it provides, from the reported activation energy at least, strong evidence that the propagating interaction of two alkylperoxy radicals proceeds in a concerted fashion. 

The rate of deprotonation of an acid by a base depends on their structures [41], on the solvent and temperature, and on the difference (ApKa) between the pKa of the acid and that of the base. When acid and base have the same pfCa (ApKa=0) the change of free energy for proton transfer becomes zero and the reaction becomes thermoneutral. Under these conditions the rate of proton transfer is limited only by the so-called intrinsic barrier [34], which is particularly sensitive to structural changes in the reaction partners [39]. When ApKa increases, the rate of proton transfer also increases and approaches a limiting value, which depends on the structures of the acid and base and on the experimental conditions. For normal acids (O-H, N-H) in water the rate of proton transfer becomes diffusion-controlled (ka=10loL mol-1 s"1) when ApKa>2, but in aprotic solvents the limiting proton transfer rate can be substantially lower [42]. 

At 1 090 °C reaction temperature and flow rates exceeding 3 Ndm3 min-1, thermoneutral conditions were achieved and no external energy supply was necessary to maintain the reaction temperature. No deactivation of the catalyst could be observed during 200 h TOS. However, 0.1 wt.% material was lost from the monolith, which was attributed to sublimation effects [45],... 

These condensation reactions often lead to the formation of isomers. Structural isomerism of bis(silyl)hydrazines was first observed in 1964.19-24 In the absence of strong steric or electronic constraints, the bis(silyl)hy-drazines such as bis(trimethylsilyl)hydrazine give in a thermoneutral reaction essentially equal amounts of the N,N- and N,N -isomers at equilibrium.7 23 Wannagat et al. found that the reaction of hydrazine with trimethylchlorosilane at room temperature results only in the formation of N,N -bis(trimethylsilyl)hydrazine, whereas the same reaction in boiling solvents leads to a mixture of N,N- and /V,/V -bis(trimcthylsilyl)hydrazine. Both could be separated by preparative gas chromatography. Their struc-... 

Gas production can be exothermal with CO2 and CH4 as products or endothermal with CO and H2 as products. Since both reactions proceed simultaneously, pyrolysis can be almost thermoneutral. Most of the energy is then required to heat up the feed material to the pyrolysis temperature. 

Consider the thermoneutral (AH = 0) mixing process that takes place in a food processing plant. Pure water (W), pure oil (O), and pure grain (G) are combined to create a livestock feed mixture (see Figure 47). While the produet flowrate F is not critical, the temperature T and composition of the product mixture, P (i.e., C fj,Co, Cq), must be precisely maintained. 

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