Authors:Maksym Pogorielov, Eugenia Husak, Alexandr Solodivnik, and Sergii Zhdanov
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
Authors:D. Minić, D. Manasijević, Jelena Ðokić, Dragana Živković, and Ž. Živković
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.
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
Authors:C. Guerreiro, C. Ribeiro, M. Crespi, and C. Torres
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.
Authors:G. Rezaei Behbehani, A. Saboury, A. Fallah Baghery, and A. Abedini
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 Kd=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
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.
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.
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