Showing papers in "Thermochimica Acta in 1994"

TL;DR: In this paper, the changes needed in the mathematical description of differential scanning calorimetry caused by periodical modulation of temperature are presented, and possible extensions of the method are suggested.

TL;DR: Modulated differential scanning calorimetry (MDSC) is a recently developed extension of DSC that adds a new dimension to the conventional approach as discussed by the authors, where the usually linear temperature program is modulated by a small perturbation, in this case a sine wave, and a mathematical treatment is applied to the resultant data to deconvolute the sample response to the perturbations from its response to a underlying heating programme.

TL;DR: In this article, a method for estimating critical temperatures (Tb) of thermal explosion for energetic materials is derived from Semenov's thermal explosion theory and the non-isothermal kinetic equation dα/dt = Af(α)e−E/RT using reasonable hypotheses.

TL;DR: In this paper, the transition of the amylose-lipid complex and the influence of lipids on starch gelatinization and retrogradation have been studied, and it is shown that not only the monoacyl chain length and the polar head but also the phase behaviour of the lipid influence the properties of the complex.

TL;DR: In this paper, some suggestions concerning the effects of each component in the starch are discussed, indicating that the structure of the amylopectin seems to be a very important factor in retrogradation.

TL;DR: In this article, a check system for the Arrhenius parameters was proposed, on the basis of the prerequisities of the methods of kinetic calculation and the properties of the general kinetic equation.

TL;DR: In this article, the authors present a recommendation of the GEFTA working group "Calibration of Scanning Calorimeters" allowing a precise heat and heat flow rate calibration of scanning calorimeters, largely independent of instrumental, sample related and experimental parameters.

TL;DR: In this article, the crystallization behavior of random ethylene copolymers is reviewed and the analysis of thermodynamic properties, the basic elements of phase structure, the purity of the crystalline phase and the supermolecular structure is given.

TL;DR: In this paper, it has been recognized that the glass transitions of food components are important in controlling mobility, which led to the development of "state diagrams" in which glass transition temperatures (Tg) of major food constituents provide a boundary between regions of low mobility (glasses) and increasing mobility (rubbers) for predicting rates of shrinkage, recrystallization, textural changes and volatile (flavor) loss in carbohydrate-based foods.

TL;DR: In this paper, a new method for the measurement of the thermal conductivity of insulating materials in the range from 0.1 to 1.5 W °C−1 m−1 was described.

TL;DR: Differential scanning calorimetry (DSC) was used to measure phase transitions and unfreezable water in fresh samples of onion, grape and strawberry after equilibration at different relative humidities as discussed by the authors.

TL;DR: In this article, the microstructures of ethylene random copolymers are evaluated using DSC fractionation by the degree of crystallinity, which is based on the same principle of separation as temperature-rising elution fractionation (Tthis article).

TL;DR: In this paper, the authors discussed the problem of extracting kinetic information on a complex process comprising consecutive reactions from thermal analysis (TA) data, and showed that the shape of the E-w dependence reflects adequately the kinetic regularities of the process being investigated.

TL;DR: In this paper, the kinetics and mechanism of the thermal decomposition of 3-nitro-1,2,4-triazole-5-one (NTO), a heterocyclic nitro triazole, have been studied, together with its morphology and evolved gaseous products, using thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy (IR), differential scanning calorimetry, X-ray diffractometry (XRD), and hot-stage microscopy.

TL;DR: In this article, a review of the molecular nature of the β, α and liquid-liquid-liquid (II) transitions in flexible-chain polymers using different thermal analysis techniques is presented.

TL;DR: In this article, power-compensated differential scanning calorimetry is applied to the determination of the thermodynamic parameters of protein denaturation in distilled water at relatively high concentration (≈5% w/w).

TL;DR: The polymorphic transition and the thermal decomposition of vaterite are characterized in this paper, and the effect of the morphology of the parent vaterites on the polymorphic and thermal properties of ex-vaterite is discussed.

TL;DR: In this paper, an analysis of the melting behavior, taking into account the broad melting region and the rigid amorphous fraction, should result in a better, more detailed description of the morphology.

TL;DR: In this paper, the effect of sample mass on the kinetics of the nonisothermal mass-loss process of molten NH4NO3 was investigated by TG-DTG, and the apparent Arrhenius parameters were shown to decrease with increasing sample mass.

TL;DR: In this article, a study was conducted using differential scanning calorimetry (DSC) and thermal mechanical analysis (TMA) to characterize the influence of freezing rate on the formation and stability of the glassy state in freeze-concentrated sucrose solutions.

TL;DR: The applications of pressure-volume-temperature (PVT) techniques to the study of semi-crystalline polymers are surveyed in this paper, where the principles of the two major experimental techniques, the piston-die dilatometer and the confining fluid apparatus, are compared and critiqued.

TL;DR: In this article, the relationship between heat evolution and the viable cell counts was investigated for the quantification of kinetic parameters for microbial growth in soil, such as Monod's substrate constant, Ks = 1.62± 0.08 mM, and the maximum microbial growth rate constant, μmax= 0.26±0.01 h−1.

TL;DR: In this paper, a peroxo-precursor is formed during the synthesis by a precipitation step from aqueous solution, and the thermal decomposition of the X-ray amorphous precursor leads directly to Mg 2 SnO 4.

TL;DR: In this article, a number of manganese dioxides have been synthesized and investigated by X-ray diffraction, electron microscopy and thermogravimetry under flowing oxygen.

TL;DR: In this paper, the thermal decomposition and surface area of the resulting MgO are found to be strongly influenced by the preparation conditions of basic magnesium carbonate, and different modes of mixing in the precipitation and also by ageing the precipitate for different periods (0.5-96 h).

TL;DR: In this paper, the molar enthalpies of mixing ΔmixHm in the liquid NaClNdCl3, KCl-Cl-3, RbCl-cl-3 and CsCl-ncl3 binary systems were measured over the whole composition range at 1124, 1065, 1122 and 1122 K, respectively, with an accuracy of about 6%.

TL;DR: In this paper, thermal analysis studies have proved to be a powerful means of probing the gelatinization process of aqueous starch system, and it has been shown that glass and melting transitions take place when heated systems are heated and that water influences the temperature of these events.

TL;DR: In this article, the thermal decomposition of calcium citrate tetrahydrate in dynamic air or dry nitrogen has been studied thoroughly and the results show that Ca3(C6H5O7)2·4H2O dehydrates in two successive steps at 60-140°C and 140-190°C each involving release of two moles of water.

TL;DR: In this paper, the thermal denaturation of β-lactoglobulin solutions was studied by differential scanning calorimetry and the kinetic parameters of heat denaturation were determined by Borchardt and Daniels method as a function of pH.

TL;DR: In this article, the authors compare the Arrhenius reaction frequency factor A with the Polanyi-Wigner theory of rates of solid state reactions and the transition state theory.