Search results for "Thermal analysis"
showing 10 items of 208 documents
Calorimetric study of myoglobin embedded in trehalose-water matrixes
2009
It has been suggested that in ‘dry’ protein–trehalose–water systems, water–mediated hydrogen bond network, whose strength increases by drying, anchors the protein to its surroundings. To further characterize this effect, we performed a DSC study on low-water myoglobin–trehalose systems. The denaturation temperature resulted to increase by decreasing hydration, and linearly correlated to the glass transition temperature of both the ternary protein–water–trehalose and the binary water–trehalose systems. Further measurements are being performed to investigate eventual differences among different saccharides.
Thermal Analysis of the Solar Orbiter PHI Electronics Unit
2020
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A comparative thermogravimetric study of waterlogged archaeological and sound woods
2010
Waterlogged archaeological woods Pinus pinaster and Fagus sylvatica L. were analyzed by using TG technique. Degradation processes ascribable to the holocellulose decay were evidenced at nearly the same temperature for sound and archaeological samples. The residual matters at 600 and 900 °C of the sound woods are much lower than those of archaeological waterlogged woods in agreement with the presence of inorganic materials encapsulated during the burial into the marine environment. It was proposed a new protocol to rapidly calculate the maximum water content parameter, which is related to the wood degradation state. TG experiments at variable heating rates were performed to obtain kinetic pa…
An Explicit Model for the Thermal-Mechanical Analysis of Hot Metal Forming Processes
1995
Abstract In the paper the authors propose a new finite element code for the coupled thermal-mechanical analysis of hot metal forming processes. As regards the mechanical problem, an explicit algorithm based on the solution of the dynamic equilibrium equation and an explicit time integration scheme is used, while the heat transfer analysis is based on the solution of the thermal equilibrium equations; in order to put the thermal problem in an explicit linear form a three level scheme has been employed for the discretization of the time variable. The model is based on a staggered procedure, in which the mechanical and the thermal analysis are carried out with respect to different time horizon…
Pyrolysis study of sol-gel derived TiO2powders
2004
An amorphous TiO2 gel was obtained by hydrolysing titanium(IV) isopropoxide with a stoichiometric amount of water using SnCl2 as catalyst. In these operative conditions, a TiO2 gel matrix containing a lower fraction of organic residual was obtained with respect to samples prepared by previously modifying the titanium alkoxide precursor with chelating ligands. Dried gel powders were characterized by N2 adsorption analyses, FT-IR and XRD measurements. Thermogravimetric (TG) and differential thermal analysis (DTA) coupled with mass spectrometric (MS) and gas chromatographic (GC) measurements were performed in order to identify the organic products released from TiO2 gel pyrolysis. The Tg-MS se…
Influence of the Preparation Temperature on the Photocatalytic Activity of 3D-Ordered Macroporous Anatase Formed with an Opal Polymer Template
2018
Even if many aspects of three-dimensionally ordered macroporous (3DOM) titania have been extensively studied, the interplay between the amorphous and crystalline components of their skeleton wall has not attracted too much attention, although it should strongly influence the properties of these materials. In order to gain new insight on this interplay, we have studied in detail the wall structure of three 3DOM titania samples prepared by heating the 3DOM titania precursor at 673, 773, and 873 K by X-ray diffraction, thermogravimetric analysis, differential thermal analysis, N2 adsorption/desorption, pore-size distribution, high-resolution transmission electron microscopy, and IHmagic-angle-…
Synthesis and thermal behavior of Janus dendrimers, part 1
2010
Abstract Eight Janus-type dendrimers up to the second generation were synthesized, and their thermal properties were evaluated. Compounds consist of the dendritic bisMPA based polyester moieties, and either 3,4-dihexyloxybenzoic acid or 3,4-dihexadecyloxybenzoic acid moieties, attached to opposite sides of the pentaerythritol core. The structures of the molecules were verified with 1 H NMR, 13 C NMR, ESI TOF mass spectrometry and elemental analysis. The thermal stability was evaluated by thermogravimetric analysis, displaying onset decomposition temperatures ( T d ) ranging from 241 to 308 °C. Phase transitions were studied by differential scanning calorimetry. Based on the performed studie…
Preparation and characterization of gels with garnet structure: A3B2C3O12, using ‘non-classical’ solvents
1992
Abstract Synthesis and characterization of some crystalline garnets by sol-gel techniques is described. The effects of emthanol, dimethyl sulfoxide (DMSO), CH2Cl2 and toluene solvents on gelation of TEOS are considered. Multicomponent gel formation in systems with stoichiometries 3CaO·Cr2O3·3SiO2 and 3CaO·Al2O2 was studied using DMSO, a polar solvent, and toluene, an apolar solvent. The dried gel was thermally treated and the powder was characterized by X-ray diffraction, differential thermal analysis/thermogravimetric analysis and scanning electron microscopy.
Thermal analysis applied to the characterization of degradation in soil of polylactide: II. On the thermal stability and thermal decompositon kinetics
2010
[EN] The disposal stage of polylactide (PLA) was assessed by burying it in active soil following an international standard. Degradation in soil promotes physical and chemical changes in the polylactide properties. The characterization of the extent of degradation underwent by PLA was carried out by using Thermal Analysis techniques. In this paper, studies on the thermal stability and the thermal decomposition kinetics were performed in order to assess the degradation process of a commercial PLA submitted to an accelerated soil burial test by means of multi-linear-non-isothermal thermogravimetric analyses. Results have been correlated to changes in molecular weight, showing the same evolutio…
Thermogravimetric analysis. A tool to evaluate the ability of mixtures in consolidating waterlogged archaeological woods
2010
Waterlogged archaeological woods (Pinus pinaster, Ulmus cf. minor and Fagus sylvatica L.) were consolidated by using Colophony, Rosin 100, and a mixture of Poly(ethylene) glycol (PEG) 3000 and Poly(propylene) glycol (PPG) 425. The efficiency of the consolidants was estimated by determining the content entrapped into the cavity of degraded wood. For this purpose, thermogravimetry was demonstrated to be a reliable tool. In the case that the polymeric mixture was used for impregnation, it was also possible to discriminate the amount of PEG 3000 from that of PPG 425 captured by the wood capillaries. Regardless of the wood nature, all the consolidants were present in treated samples in large amo…