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Abstract  

After a formal explanation of Mayer's enthalpy balance method as applied to biological reaction rates, the history of its application is traced from Rubner's dog to accounting for the energy of muscle contraction. The introduction of microcalorimetry allowed the method generally to be used for cells in vitro and now particular emphasis can be paid to the growth of cells for the production of therapeutically-important heterologous proteins. In these systems, enthalpy balance studies contribute to defining catabolic processes, designing media, understanding the mechanisms of growth and controlling cultures using heat flux as an on-line sensor of metabolic activity.

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Journal of Thermal Analysis and Calorimetry
Authors: Christelle Herman, Tom Leyssens, Valérie Vermylen, Véronique Halloin, and Benoît Haut

enthalpy balance. Specified zone related to the melting peak Stable compound—form II The zone considered on the curve of a stable compound for the determination of its melting enthalpy is presented in Fig

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Abstract  

The intercalation process ofn-butylamine was investigated. The adsorption ofn-butylamine in interlamellar space had stepwise character in case of both crystalline forms of zirconium phosphate. The intercalatedn-butylamine existed at low concentration as bilayered complex. The reaction heat was determined by a microcalorimetric method. It was found that about 90% of it refers to the neutralization ofn-butylamine and only about 10% is related with surface adsorption (ion exchange). The steps of adsorption are 6.0 J/g and 1.0 J/g reaction heat values, respectively. The enthalpy balance of total process in dilute solution system (c 0=3.0 vol%) is 14.67 kJ/mol. The calculated value for ion adsorption (exchange) was 1.37 kJ/mol.

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Abstract  

Microcalorimeters to monitor the heat dissipation of bench-scale animal cell cultures on line and in real time require a continuous circuit between the vessel measuring heat flow rate and the bioreactor. The modifications to the transmission lines and calorimetric heat exchanger were to: (i) reverse the usual upward direction of the cell suspension in the flow vessel to downwards; (ii) install an in situ washing/cleaning facility; (iii) use low diffusivity PEEK material; and (iv) maintain thermal equilibration by water-jacketing the transmission tubing. Chemical calibration showed that there was more than a 20% difference between the physical volume and the effective thermal volume. An appropriate thermodynamic system was defined in order to permit enthalpy balance studies.

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Journal of Thermal Analysis and Calorimetry
Authors: N. Barros, S. Feijóo, J. Simoni, C. Airoldi, B. Ramajo, A. Espina, and J. García

Abstract  

The control on the CO2 coming from soil handling, makes necessary the introduction of new methodologies that inform about the capacity of the soil as a carbon sink and about the carbon decay. It can be performed through the microbial growth yield efficiency concept by calorimetry and enthalpy balances. Here it is examined the sensitivity of these indicators to two metal layering phosphates, AZP [(NH)4Zn2(PO)4(HPO)4] and AIP [(NH)4Fe(PO)4H2O] to assess about their soil impact. Both compounds caused metabolic changes on soil microbial biomass when compared to appropriated references indicating that the proposed methodology is sensitive to different inorganic sources of microbial growth.

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Abstract

The specific heat and the enthalpy variation of a highly deuterated crystal of ferroelectric triglycine selenate have been measured around its first-order phase transition using the technique square modulated differential thermal analysis (SMDTA). The low temperature variation rate has allowed analyzing the kinetics of the phase transition. Due to an internal crack in the sample, the transition is carried out in two steps and an intermediate region where the transition is blocked and both phases coexist without transformation has been found. The latent heat on cooling (L c=1.32±0.02 J g−1) is higher than on heating (L h=1.08±0.02 J g−1) due to the thermal hysteresis and the great difference between the specific heat in both phases. Nevertheless, the enthalpy balance is fulfilled on heating and on cooling.

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about 1 − 2 kJ/UCFW. Their opinion is that this value is sufficiently small compared to the enthalpy of combustion that the latter can be used without further correction to calculate enthalpy balances for wet biomass. The simplicity of

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