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Abstract  

The CISORP Water Sorption Analyser has been used to characterise a selection of solid samples at relative humidities from 0 to 100% and at ambient pressure. The analysis reveals many interesting features about the samples and shows the scope of the equipment. Hysteresis due to porosity and differences in the physical properties of similar chemical samples show up clearly in isotherm curves. Kinetic curves reveal features such as the level of stability of dehydrated food products, changes in the hydration states of salts, and the effect of adding powdered excipient on the water sorption behaviour of a pharmaceutical compound. Kinetic curves were also used to compare the water sorption behaviour of two types of wood found inside a pine cone, and to determine equilibrium moisture sorption by calculation. It was shown that many samples take up moisture irreversibly under the experimental conditions such as amorphous sucrose and other freeze-dried samples, as well as unstable crystalline forms of compounds. Wet samples such as soaked brick and archaeological wood from a well dry out irreversibly even at 100% RH. Recording isotherms at different temperatures allows the calculation of enthalpies of water sorption. If these are compared with the enthalpy of water condensation the two processes can be compared quantitatively.

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Abstract

The dendrite coherency point (DCP) temperature refers to the state of a solidifying alloy at which a coherent dendrite network is established during the formation of grains. Several relatively complex methods for detection of the DCP temperature have been developed. There are four main DCP temperature testing approaches: (i) the rheological technique, (ii) thermal analysis of the minimum temperature difference between two cooling curves, (iii) thermal analysis of the second derivative of one cooling curve, and (iv) the thermal diffusivity measurement technique. This paper follows up the proposed thermal analysis of one center cooling curve for the determination of the DCP characteristics such as: temperature, time, instantaneous solidification rate, and fraction solid. The first derivative of the cooling curve is plotted versus the temperature and time and the thermal characteristics of all metallurgical reactions, including the DCP are determined with the same accuracy achieved using the two thermocouple technique developed by Bäckerud et al. [, ]. Statistical analysis of the DCP temperature using the one versus two thermocouple techniques shows R 2 equal to 0.99. This research revealed that utilization of dT/dt versus the temperature curve methodology also allows for analysis of the α-Al dendrite nucleation and growth characteristics and consequent determination of the grain size. On-going work on this new methodology for characterization of other solidification events will be presented in subsequent papers.

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The Unified Grain Moisture Algorithm is capable of improved accuracy and allows the combination of many grain types into a single “unified calibration”. The purposes of this research were to establish processes for determining unifying parameters from the chemical and physical properties of grains. The data used in this research were obtained as part of the United States Department of Agriculture-Grain Inspection, Packers and Stockyards Administration's Annual Moisture Calibration Study. More than 5,000 grain samples were tested with a Hewlett-Packard 4291A Material/Impedance Analyzer. Temperature tests were done with a Very High Frequency prototype system at Corvinus University of Budapest. Typical chemical and physical parameters for each of the major grain types were obtained from the literature. Data were analyzed by multivariate chemometric methods. One of the most important unifying parameters (Slope) and the temperature correction coefficient were successfully modeled. The Offset and Translation unifying parameters were not modeled successfully, but these parameters can be estimated relatively easily through limited grain tests.

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25 C 2 > 1 > 10 > 3 > 9 > 7 > 4 > 6 > 5 > 8 2 > 1 > 10 > 3 > 7 > 4 > 9 > 6 > 5 > 8 In the following analysis, the temperature tested by the 3rd probe is

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Profile Analysis (TPA) test by TA-XTplus (Stable Micro System, Surrey, UK) Texture Analyzer with P/25 type stainless steel cylinder at room temperature. Test setting were as follows: compression with pre-test speed 2 mm/s, test speed 1 mm/s, post

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temperature test. Fan et al. [ 10 ] performed laboratory tests on eight square sections to study the resistance of stainless-steel box columns under high temperature. Neural network is a new method that has been applied for elaborating heat data, but it never

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Biodiesels from beef tallow/soybean oil/babassu oil blends

Correlation between fluid dynamic properties and TMDSC data

Journal of Thermal Analysis and Calorimetry
Authors: G. A. A. Teixeira, A. S. Maia, I. M. G. Santos, A. L. Souza, A. G. Souza, and N. Queiroz

. The values of T onset and T P , obtained in the TMDSC cooling curves of the biodiesel samples, showed a correspondence with the values of the low-temperature tests, determined by conventional methods, Fig. 4 . The values of CP (5–12 °C) and CFPP (4

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. Actually, the temperature tested in the experiment is not the sample's real temperature, because the released heat not only contributed to the sample itself but also to the bombs of the sample. Assuming that the heat released from the reaction is used to

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composition of the sinters was identified by X-ray powder diffraction at room-temperature. Testing procedure showed that all samples of the system of interest melted in excess of 1400 °C. Accordingly, to draw the liquidus curves the samples after pressing into

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Journal of Thermal Analysis and Calorimetry
Authors: Javier A. Díaz-Ponce, Eugenio A. Flores, Alfonso Lopez-Ortega, Jose G. Hernández-Cortez, Arquimides Estrada, Laura V. Castro, and Flavio Vazquez

of the first cycle regarding the sample's stability, and to corroborate the peak's position. These low-temperature tests are non-destructive; several measurements can be performed by using the same sample, considering that at 30 °C, the thermal

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