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Acta Alimentaria
Authors: K. Szentmihályi, M. Szilágyi, J. Balla, L. Ujhelyi, and A. Blázovics

. 1999 6 45 Fazekas , T., Selmeczi , B. & Stefanovits , P. (1994): Magnesium in biological systems

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corrosion properties after providing structural support for a certain period to complete both the regeneration and the healing processes. Iron (Fe), zinc (Zn), and magnesium (Mg) are considered as the basic biodegradable materials for medical

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930 Hans, C. P., Sialy, R., Bansal, D. B.: Magnesium deficiency and diabetes mellitus. Curr. Sci., 2002, 83 , 1456–1463. Bansal D. B

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Silicothermic reduction process in magnesium production

Thermal analysis and characterization of the slag

Journal of Thermal Analysis and Calorimetry
Authors: D. Minić, D. Manasijević, Jelena Ðokić, Dragana Živković, and Ž. Živković

Abstract  

In this paper there are presented the results of the characterization and thermal analysis of the slag from the magnesium plant ‘Bela Stena’, Serbia. The results of X-ray fluorescence analysis, scanning electron microscopy (SEM), optical microscopy (LOM) and X-ray diffraction (XRD) were used for chemical and mineralogical analysis of the solidified slag samples. Differential thermal analysis (DTA), thermo-gravimetric (TG) analysis and thermal microscopy results were used for determination of characteristic phase transformations. The solidified slag shows dicalcium silicate based structure. Magnesium is mostly present in the form of the following minerals: periclase, merwinite and melilite.

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Abstract  

The ageing characteristics of pyrotechnic compositions are influenced not only by temperature, but also by surrounding effects as humidity and vibrations. In this paper the thermal stability of the pyrotechnic system magnesium–sodium nitrate will be investigated. In an inert helium atmosphere two steps of mass loss, which were not completely separated from each other, were observed in the temperature range from 65 to 265C: a mass loss of about 15% between 65 and 160C and about 34% between 160 and 265C. It is assumed that these two steps are caused by different processes. The separation between the two steps was not or hardly detectable for measurements that were performed in a nitrogen atmosphere. Using MS and FTIR (mass spectrometry/Fourier transform infrared spectroscopy) the evolved gases were analysed. Only above about 170C evolving gases were detected (which means that during the first step no gases were detectable). The detected gas mainly consists of CO2, CO and N2O, with smaller amounts of NO2, NO and possibly HCN. A third step of mass loss (8–9%) was observed above 314C. The process which caused this step of mass loss is considered not to contribute significantly to the ageing of the material at much lower temperatures of maximum 80C, which is of interest in view of the use of the materials. Kinetic parameters for the processes which caused the first and the second step of mass loss were evaluated from kinetic analysis of the measured TG curves. By using these results the conversion can be predicted as a function of time and temperature. However, it must be considered that the inaccuracy of the predictions increases if the temperature for which the prediction is calculated is further away from the temperature at which the experiments were performed. This is caused by the exponential form of the kinetic equations. The calculations show that in particular the reaction which causes the first step of mass loss can run relatively quickly in the temperature range 25–80C, which could result in ageing of the material during storage at these conditions. The reaction which causes the second step of mass loss clearly runs at a much lower rate.

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Abstract  

Magnesium ion was reacted with 5,7-dibromo-, 5,7-dichloro-, 7-iodo-and 5-chloro-7-iodo-8-hydroxyquinoline, in acetone/ammonium hydroxide medium under constant stirring to obtain (I) Mg[(C9H4ONBr2)2]2H2O; (II) Mg[(C9H4ONCl2)2]3H2O; (III) Mg[(C9H5ONI)2]2H2O and (IV)Mg[(C9H4ONICl)2]2.5H2O complexes. The compounds were characterized by elemental analysis, IR spectra, ICP, TG-DTA and DSC. Through thermal decomposition residues were obtained and characterized, by X-ray diffractometry, as a mixture of hexagonal MgBr2 and cubic MgO to the (I) compound at 850C; cubic MgO to the (II), (III) and (IV) compounds at750, 800 and 700C, respectively.

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Abstract  

Binding properties of myelin basic protein (MBP) from bovine central nervous system due to the interaction by divalent magnesium ion (Mg2+) was investigated at 27°C in aqueous solution using isothermal titration calorimetry (ITC) technique. An extended solvation model was used to reproduce the enthalpies of Mg2+-MBP interaction over the whole Mg2+ concentrations. It was found that there is a set of two identical and noninteracting binding sites for Mg2+ ions. The dissociation equilibrium constant is K d=45.5 μM. The molar enthalpy of binding site is identical for both sites; ΔH=−15.24 kJ mol−1. The solvation parameters recovered from the solvation model were attributed to the structural change of MBP due to the metal ion interaction.

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Abstract  

Thermal analysis of magnesium tris(maleato) ferrate(III) dodecahydrate has been studied from ambient to 700C in static air atmosphere employing TG, DTG, DTA, XRD, Mssbauer and infrared spectroscopic techniques. The precursor decomposes to iron(II) intermediate species along with magnesium maleate at 248C. The iron(II) species then undergo oxidative decomposition to give α-Fe2O3 at 400C. At higher temperatures magnesium maleate decomposes directly to magnesium oxide, MgO, which undergoes a solid state reaction with α-Fe2O3 to yield magnesium ferrite (MgFe2O4) at 600C, a temperature much lower than for ceramic method. The results have been compared with those of the oxalate precursor.

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Alanine- and taurine-salicylal Schiff base complexes of magnesium

Synthesis, characterization and thermal decomposition

Journal of Thermal Analysis and Calorimetry
Authors: S. Luan, Y. Zhu, and Y. Jia

Abstract  

The complexes of α-alanine-salicylal Schiff base of magnesium (α-ASSM), β-alanine-salicylal Schiff base of magnesium (β-ASSM) and taurine-salicylal Schiff base of magnesium (TSSM) were synthesized. The formulae of the complexes are Mg[OC6H4CHNCH(CH3)COO]·2H2O, Mg[OC6H4CHNCH2CH2COO]·2H2O and Mg[OC6H4CHNCH2CH2SO3]·2H2O. The crystal structure belongs to orthorhombic system with the lattice parameters: a=1.6954 nm, b=2.0873 nm and c=2.3037 nm for the β-ASSM, to orthorhombic system with the lattice parameters: a=1.5586 nm, b=1.8510 nm and c=2.6240 nm for the β-ASSM, to monoclinic system with the lattice parameters: a=1.3232 nm, b=1.4960 nm, c=2.1543 nm and β=98.04° for the TSSM, respectively. The results of the thermal decomposition processes and infrared spectra of the complexes show that the complexes may possess different coordination structures.

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különböz NPK m trágyázási szinten termesztett Bezosztaja-1 szi búza Mg-felvétele. (Uptake of magnesium in the winter wheat variety Bezostaya 1 grown with different amounts of NPK mineral fertiliser.) Búzatermesztési Ksérletek , 1960-70, 57

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