The decomposition processes of a carburised Fe–C alloy, a Fe–C, a Fe–Cr–C and commercial SAE 52100 cast alloys (with a C content
of about 1 mass%) have been studied by means of differential scanning calorimetry and dilatometry. The combination of these
two experimental techniques is very powerful and allows the identification of all the stages occurring during tempering. Activation
energies have been obtained by performing a Kissinger-like analysis and were used to infer the rate-determining step for each
stage of decomposition. This parallel investigation allowed to determine the effect of the alloying elements on the different
stages of tempering.
Authors:G. Baert, S. Hoste, G. De Schutter, and N. De Belie
Four paste mixtures with varying replacement level of the cement content by fly ash have been studied. Due to fly ash, the
acceleration period decreased and a third hydration peak was noticed with isothermal calorimetry. The total heat after 7 days
increased with increasing fly ash content. From 1 to 7 days, thermogravimetry showed a higher chemically bound water and Ca(OH)2-content for the pastes with fly ash. Between 7 and 14 days the calcium hydroxide started to be depleted due to the pozzolanic
reaction. A unique relation was found between calcium hydroxide and total heat development.
After a short survey of the development of adsorption calorimetry, the current position of this method is demonstrated in the light of some more recent results. A critical analysis is made of the areas in which adsorption calorimetry could be successfully applied in the future, either alone or, preferably, in combination with other techniques.
Authors:L. Bernazzani, C. Cardelli, G. Conti, and P. Gianni
The miscibility of blends of poly(vinyl-chloride) (PVC) with poly(ethylene-co-vinyl acetate) (EVA) was investigated through analog calorimetry and a group contribution procedure based on the UNIQUAC
model. The group contribution parameters quantifying the pair interactions between the structural features of the above polymers
were calculated from experimental excess enthalpies of a series of binary mixtures of chlorocompounds, esters and hydrocarbons.
Enthalpy data were also collected for the ternary mixtures (2-chloropropane+ethyl acetate+n-heptane) and (2-chlorobutane + methyl acetate+n-heptane), chosen as possible models for the studied macromolecular mixtures. The miscibility window of the PVC-EVA blends
is fairly predicted by the group contribution method. It is also acceptably predicted by the enthalpic behaviour of the first
ternary set, but only when the latter is calculated with binary data. A slightly narrower miscibility range is predicted by
the binary interaction model. The results of these procedures are compared and the higher reliability of the group contribution
procedure is emphasized in terms of its capability to reproduce the exact structure of the macromolecules and the non-univocal
choice of the model molecules involved in the analog calorimetry approach.
Authors:Hideki Saitoh, Satoaki Ikeuchi, and Kazuya Saito
Summary Crystal structures of the room-temperature (RT) and low-temperature (LT) phases of p-methylbenzyl alcohol were reexamined by single-crystal X-ray diffraction method while paying special attention to detect structural disorder in the RT phase involved in successive structural phase transitions at 179 and 210 K. In the RT phase at 250 K, positional disorder of oxygen atoms was detected in contrast to the previous structure report. The structure of the LT phase coincided to the previous one. Heat capacities were measured by adiabatic calorimetry below 350 K, which covers the structural phase transitions and fusion at 331.87 K. The structural phase transitions were of first-order and required long time for completion. The combined magnitude of entropies of transition was ca. 5 J K-1 mol-1, a part of which can be ascribed to the positional disorder observed in the structure analysis. Standard thermodynamic functions are tabulated below 350 K.
Authors:E. Schmolz, S. Geisenheyner, B. Schricker, and I. Lamprecht
Heat production rates and flight speed of adult wax moths (Galleria mellonella) were investigated by means of direct calorimetry
at TA=20 and 30C. Specific heat production rates were not significantly different between males and females at TA=20C (pTH=747123.7 mW g-1, n=5 for males and pTH=791169 mW g-1, n=5 for females) even with females having a higher body mass (MB=83.821.6 mg, n=9 for males and MB=146.425.7 mg, n=11 for females) and wing load. In females, heat production rates were dependent on temperature with higher
heat production rates at TA=20C (pTH=791169 mW g-1, n=5) than at TA=30C (pTH=44174 mW g-1, n=6). Flight speed was also clearly correlated with TA. Both males and females flew more slowly at TA=20 than at 30C.
Authors:S. Aubuchon, L. Thomas, W. Theuerl, and H. Renner
40% w/w sucrose/water solutions were analyzed by Modulated Differential Scanning Calorimetry  in the sub-ambient temperature region. At these temperatures, the solutions exhibit a complex, two-step thermal event. The lower-temperature event is believed to be the glass transition of the amorphous sucrose phase. The nature of the higher-temperature event is the subject of controversy. This event has been shown to have distinct second-order characteristics, and as such is believed to be a second Tg. Others feel that this event is the onset of melting. The temperature region between these events contains a devitrification exotherm. Through the use of MDSC, both in scanning and stepwise quasi-isothermal modes, improved sensitivity and resolution of MDSC provides new insight into the nature of these transitions.
The glass-forming tendency and specific heat in ice cold water-quenched Ge1−xSnxSe2.5 glassy alloys with 0<x<0.6 were investigated by means of differential scanning calorimetry. The heat of fusion ΔHf, the heat ΔHc associated with the crystallization of an amorphous phase and the glass transition temperatureTg were deduced from the DSC curves. The composition dependence of glass forming ability,Tg and crystallization behavior has been discussed.
Authors:Katarzyna Drozdzewska, V. Kestens, A. Held, G. Roebben, and T. Linsinger
The application of differential scanning calorimetry (DSC) for purity determination is well documented in literature and is
used amongst others in the analysis of pure organic crystalline compounds. The aim of this work is to examine whether the
DSC method for purity determination consistently produces values for the purity of polycyclic aromatic hydrocarbons (PAHs)
which are sufficiently accurate as required for the certification of reference materials. For this purpose, 34 different existing
PAH certified reference materials were tested. The DSC results are shown to be consistent with the results obtained by other
methods assessing the organic impurities content in PAHs, like gas chromatography (GC), high performance liquid chromatography
(HPLC) and mass spectrometry. Significant differences between the measured values and the certified purity values were observed
only in a limited number of cases.
Authors:Y. Yoshihashi, H. Iijima, E. Yonemochi, and K. Terada
stability of amorphous drug in solid dispersion was estimated using differential
scanning calorimetry (DSC). Tolbutamide (TB) and flurbiprofen (FBP) were selected
as insoluble drugs in water. Polyvinylpyrrolidone (PVP) was selected as a
polymer for solid dispersion. Solid dispersions of various ratios of TB or
FBP and PVP-K25 were prepared by solvent evaporation method and the induction
period of crystallization from amorphous drug in solid dispersion was measured
by DSC. Compared with FBP, the induction period of crystallization from TB
was delayed by an addition of PVP. The improvement of the physical stability
by the addition of PVP-K25 was estimated from the activation energy of diffusion
of drug molecules and the interfacial free energy between drug crystal and
supercooled liquid of drug in solid dispersion. From thses results, the hindrance
of the diffusivity of the drug molecule might be mainly affected the delay
of the induction period of crystallization of TB and FBP.