| 1. |
- Amirinejhad, Sajad, et al.
(author)
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Calorimetric study of the oxidation of Al-Mg alloys for the prediction of healing of the double oxide film defect
- 2013
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In: Journal of thermal analysis and calorimetry (Print). - : Springer. - 1388-6150 .- 1588-2926 .- 1572-8943. ; 113:2, s. 769-777
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Journal article (peer-reviewed)abstract
- The oxidation of Al alloys containing 0.3-4.5 wt% Mg in an atmosphere with a very low oxygen partial pressure (< 0.5 ppm, to depict the atmosphere within a double oxide film defect) was studied using differential scanning calorimetry and scanning electron microscopy. The results showed that a newly formed Al2O3 layer held in an Al-Mg melt first transformed to MgAl2O4 spinel and then to MgO. This mechanism was the same for all the Al alloys containing 0.3-4.5 wt% Mg, but the kinetics of the transformations were different and depended on the Mg content of the melt. The results also suggest that the two layers of a double oxide film defect that is held in an Al melt containing 0.3-4.5 wt% Mg can heal (i.e. bond to each other) if held in the liquid metal for a long enough period of time.
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| 2. |
- Briggner, Lars-Erik, et al.
(author)
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Design and testing of a small-scale sublimation apparatus
- 2009
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In: Journal of Thermal Analysis and Calorimetry. - : Springer Science and Business Media LLC. - 1588-2926 .- 1388-6150 .- 1572-8943. ; 98:1, s. 331-335
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Journal article (peer-reviewed)abstract
- In many areas of scientific research and development, for example in the pharmaceutical industry, it is important to prepare and to characterize crystals of pure organic compounds which are thermodynamically stable. The formation of crystals from the gas phase is technically less straightforward than crystallisation from solution, but sublimation techniques can have several important features. In the present paper we report the design and testing of a novel apparatus for small scale sublimation and fractional deposition of crystals. The instrument has been developed with special reference to the needs in the pharmaceutical industry. A few mg of the samples are enclosed, under reduced pressure, in thin-walled glass tubes, along which a well defined temperature gradient can be formed. During an experiment the substance will sublime from the hot end of the glass tube and crystals will be deposited along the temperature gradient. The applicability of the instrument has been verified by experiments with several test compounds. Results from experiments with carbamazepine, are reported in some detail. Carbamazepine single crystals of high quality were obtained and the transition temperature between the triclinic (Form I) and the monoclinic (Form III) crystal modifications agreed with literature values.
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| 3. |
- Ciesla, K, et al.
(author)
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DSC studies of gamma-irradiation influence on amylose-lipid complex transition in wheat flour
- 2005
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In: Journal of Thermal Analysis and Calorimetry. - : Springer Science and Business Media LLC. - 1588-2926 .- 1388-6150 .- 1572-8943. ; 79:1, s. 19-27
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Journal article (peer-reviewed)abstract
- DSC studies were carried out in the heating-cooling cycles for non-irradiated and irradiated with gamma-rays ((CO)-C-60) using 30 kGy dose wheat flour. The differences between gelatinisation and reversible transition of amylose-lipid complexes occurring in suspensions of non-irradiated and the irradiated flour (characterized by a dry matter to water ratio of 1: 1 and 1:3) depend on the conditions applied in DSC measurements (concentration, heating/cooling rate) and on the preceding treatment of samples. An essential decrease in the temperature of amylose-lipid complex transition was discovered after irradiation. Retrogradation is inhibited in the dense gels of the irradiated samples as compared to the initial ones. The results are discussed in terms of radiation-induced destruction of the polysaccharide chains and lipid modification.
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| 4. |
- Lamprecht, I, et al.
(author)
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Discontinuous ventilation in the rhinoceros beetle Oryctes nasicornis. Direct and indirect calorimetry
- 2009
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In: Journal of Thermal Analysis and Calorimetry. - : Springer Science and Business Media LLC. - 1588-2926 .- 1388-6150 .- 1572-8943. ; 95, s. 743-747
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Journal article (peer-reviewed)abstract
- Discontinuous gas exchange cycles (DGCs) are frequently observed with insects, i.e. oxygen take up and carbon dioxide release occur interrupted by periods of a few minutes up to many hours. The paper presents direct and indirect calorimetric experiments on DGCs of the scarabid rhinoceros beetle Oryctes nasicornis. A direct/indirect calorimetric experiment is presented. Total and specific heat production rates amount to 0.56mWand 0.42mWg–1 in the first period without DGCs and to 0.43 mW (0.32 mW g–1 ) in the second phase, resp. The mean DGC amplitude is 0.184 mW and thus between 33 and 66% of the total turnover.
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| 5. |
- Li, Yujing, et al.
(author)
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Simultaneous measurements of colony size and heat production rate of a mould (Penicillium brevicompactum) growing on agar
- 2011
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In: Journal of Thermal Analysis and Calorimetry. - : Springer Science and Business Media LLC. - 1588-2926 .- 1388-6150 .- 1572-8943. ; 104:1, s. 105-111
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Journal article (peer-reviewed)abstract
- Fungal colony size development, often measured as the increase in colony diameter, is used frequently as a parameter for presenting and modelling fungi's biomass growth. Another measure of fungal growth is the heat production rate (thermal power), which represents the metabolic activities of the fungi. In this study, the colony size and the heat production rate were simultaneously measured on a filamentous fungus, Penicillium brevicompactum, at five temperatures. The colony growth was recorded by digital photography and the colony size was quantified by image analysis. The heat production rate was measured by an isothermal calorimeter. The results showed that the growth of mould is temperature dependent. During the active growing stage, the colony size increase is correlated to the heat produced by the mould.
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| 6. |
- Robinson, Ryan, et al.
(author)
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Low temperature reactivity in agglomerates containing iron oxide : Studies in the Ca(OH)2-C-Fe2O3 system
- 2011
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In: Journal of thermal analysis and calorimetry (Print). - : Springer Science and Business Media LLC. - 1388-6150 .- 1588-2926 .- 1572-8943. ; 103:1, s. 185-193
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Journal article (peer-reviewed)abstract
- In this study, we have attempted to explain the complex reactions that occur during the dehydration of Ca(OH)2, in the presence of solid carbon and Fe2O3, in order to clarify their role as eventual precursors to the reduction and high temperature strength characteristics in feedstock agglomerates of iron and steelmaking by-products. A series of simultaneous thermo-gravimetric (TG), differential thermal analytic (DTA), and mass spectrometric (MS) tests were performed on agglomerated sample mixes of Ca(OH)2, C, and Fe2O3 to test the influence of heating rate and particle size on the transformations occurring below 1,073 K in inert atmosphere. The overall transformation begins with calcium hydroxide dehydration. Nucleation and growth of CaO grains during dehydration, as well as subsequent gasification of solid carbon, are highly dependent on the governing interstitial particle porosity and mildly dependent on the heating rate in and around agglomerates. The reduction of hematite in current agglomerates is, by association to preceding reactions, partly dependent on porosity and heating rate, but the mechanism of reduction was also found to be highly dependent on the particle size of iron oxides. Furthermore, in areas of intimate contact between CaO and iron oxide, a calcium ferrite phase appears in the form of angular and calcium-rich particles.
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| 7. |
- Sundar, Smith, et al.
(author)
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Thermal characterization and electrical properties of Fe-modified cellulose long fibers and micro crystalline cellulose
- 2011
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In: Journal of thermal analysis and calorimetry (Print). - : Springer Science and Business Media LLC. - 1388-6150 .- 1588-2926 .- 1572-8943. ; 104:3, s. 841-847
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Journal article (peer-reviewed)abstract
- Thermal properties of polylactic acid (PLA) filled with Fe-modified cellulose long fibers (CLF) and microcrystalline cellulose (MCC) were studied using thermo gravimetric analysis (TG), differential scanning calorimetry, and dynamic mechanical analysis (DMA). The Fe-modified CLFs and MCCs were compared with unmodified samples to study the effect of modification with Fe on electrical conductivity. Results from TG showed that the degradation temperature was higher for all composites when compared to the pure PLA and that the PLA composites filled with unmodified celluloses resulted in the best thermal stability. No comparable difference was found in glass transition temperature (Tg) and melting temperature (Tm) between pure PLA and Fe-modified and unmodified CLF- and MCC-based PLA biocomposites. DMA results showed that the storage modulus in glassy state was increased for the biocomposites when compared to pure PLA. The results obtained from a femtostat showed that electrical conductivity of Fe-modified CLF and MCC samples were higher than that of unmodified samples, thus indicating that the prepared biocomposites have potential uses where conductive biopolymers are needed. These modified fibers can also be tailored for fiber orientation in a matrix when subjected to a magnetic field
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| 8. |
- Wadsö, Ingemar
(author)
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Characterization of microbial activity in soil by use of isothermal microcalorimetry
- 2009
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In: Journal of Thermal Analysis and Calorimetry. - : Springer Science and Business Media LLC. - 1588-2926 .- 1388-6150 .- 1572-8943. ; 95:3, s. 843-850
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Conference paper (peer-reviewed)abstract
- Isothermal microcalorimetry is now established as a useful technique for the characterization of the microbial activity in soil. A brief summary of publications from this field and of instruments used in such work is presented. Several experimental parameters that can form important sources for systematic errors are discussed and it is suggested that further method work is made in this area. In most isothermal microcalorimetric investigations on the microbial activity in soil, the samples are amended with glucose. It is proposed that cellulose also will be used.
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| 9. |
- Wadsö, Ingemar, et al.
(author)
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Systematic errors in isothermal micro- and nanocalorimetry
- 2005
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In: Journal of Thermal Analysis and Calorimetry. - : Springer Science and Business Media LLC. - 1588-2926 .- 1388-6150 .- 1572-8943. ; 82:3, s. 553-558
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Journal article (peer-reviewed)abstract
- Results of calorimetric measurements are easily impaired by different kinds of systematic errors. Isothermal micro- and nanocalorimeters are particularly sensitive to such errors, as the measured thermal powers are very low. In this paper the occurrence and effects of such errors are discussed: calibration errors, baseline errors, problems with evaporation/condensation, sorption, pV-work, gaseous reactants and different kinds of mechanical effects. Several numerical examples are given.
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| 10. |
- Wadsö, Lars, et al.
(author)
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Biological applications of a new isothermal calorimeter that simultaneously measures at four temperatures
- 2011
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In: Journal of Thermal Analysis and Calorimetry. - : Springer Science and Business Media LLC. - 1588-2926 .- 1388-6150 .- 1572-8943. ; 104:1, s. 119-126
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Conference paper (peer-reviewed)abstract
- Isothermal calorimetry is a powerful technique for the study of kinetics of physical, chemical, and biological processes, for example, of their temperature dependence. A new heat conduction calorimeter that simultaneously makes measurements on four samples at four different temperatures is presented in this article. Results from tests with four biological systems (milk fermentation, carrot juice spoilage, sunflower seed germination, and moss respiration) are shown. In all the cases, the instrument could measure the heat production rate-and thus the process rate-at the different temperatures used.
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