Specific heat production

Figure 4-60 shows the maximum allowable level at room temperature calculated for different maximum specific heat production rates and a total batch volume of 6 m. ... 

The Figure 4-60 shows that only reactions with maximum specific heat production rates of less than 130 W/kg are safety technically acceptable if the batch size amounts to 6 m. If the maximum specific power output is expected to be higher, the batch size has to be reduced. The limit curve has to be recalculated for each batch size because the maximum vapour velocity in the reactor directly depends on this batch size. For the sample process considered, Figure 4-61 additionally provides the curves for a 5 m batch size. It can be seen that in the case of this reduced total batch volume, maximum reaction power outputs up to 400 W/kg could be tolerated. 

The amount of heat produced during a reaction per unit of reactor volume, that is, specific heat production (, .), is the product of the effective reaction rate and reaction enthalpy ... 

Figure 9.13 Averaged specific heat production rates 0 during the metamorphosis of single honeybees in a wax cell from larva (L), prepupal stage (V), and molt (Ml) (left part) via pupa P (middle part), a second molt...

MTp = stack solid mass-specific heat product (J/K)... 

Figure 10. Activities of samples, untreated or treated with Aliquat. The broken lines combine start- and end-experiments. Symbols (O) control ( ) 10 ( ) 100 and (A) 1000 mg Aliquat per 1. A. Specific heat production, during incubation in calorimetric ampoules. B. Oxygen uptake rate and C. Carbon dioxide production rate during incubation in manometer vessels. Reproduced with permission from reference [107] copyright OIKOS.

Group effects are rather common among insects, leading to a reduced mass specific heat production rate compared to that of an isolated animal when several individuals of the same species are put together in the calorimeter. Prat [85] showed that the heat dissipation of a female fruit fly Drosophila) of about 1 mg dropped from 0.12 mW to 0.08 mW when together with 4 further fruit flies. This effect is even more pronounced in social insects like honeybees which produce a collective thermogenesis resulting in social homeothermy. 

Custom-made simple thermocouple calorimeters of 0.25 mL active volume and a sensitivity of 20 pV/mW were applied to study the growth regulating and toxic effects of Ledum palustre extracts on the growth of pupae of T. molitor [103]. They exhibited the U-shaped course of mass-specific heat production rate (max. 2.8 mW/g, min. 1.2 mW/g) as described also by other authors (e.g. [88,92]). Superimposed on the slope were longer-lasting clear endothermic structures during... 

Microcalorimetric experiments were used to analyse the well-known drastic temperature increase in laboratory cultures of Galleria mellonella during larval development. The authors showed that the temperature rise was due to an approximately threefold increase in mass specific heat production rates from about 50 mW/g for the larval stage L3 to about 140 mW/g for L4 and L5 (followed by a drop to 75 mW/g for L6) [104]. The observed aggregation of larvae inside silken tubes was thus unlikely to be responsible for the temperature jump from 32 to 40 °C during stages L4 and L5 vidiich are typical for G. mellonella in laboratory cultures. 

Figure 15. Weight specific heat production rate of honeybee workers (A. m. car-nica) at 30 °C as function of the group size [56].

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