Search Results

You are looking at 11 - 20 of 71 items for :

  • "thermal analysis" x
  • User-accessible content x
Clear All

glass crystallization, determined from the DSC curve. For the purpose of examination of the thermal properties of the glass-waste mixtures, their thermal analysis was carried out. Measurements were taken using the STA 449 Jupiter F3 apparatus of

Open access

characterization techniques such as the X-ray analysis (XRD), ICP-AES, EDAX, Brunauer–Emmett–Teller (BET), Thermogravimetric/Differential Thermal Analysis (TGA/DTA), while catalytic evaluation for soot oxidation was performed using the TGA method. The results

Open access

Abstract

The subsolidus phase relations of the ternary system CoO–In2O3–V2O5 were investigated by differential thermal analysis and X-ray diffraction techniques. It has been shown that the system consists of seven subsidiary systems in which three solid phases coexist in equilibrium. The melting temperatures of these subsystems have also been determined.

Open access

Abstract  

The adsorption of MCPA and 2,4-D on the activated carbon Filtrasorb 300 was studied. The adsorption isotherms of herbicides from aqueous solutions were measured over a wide range of solute concentrations and at different temperatures. The experimental equilibrium data were analyzed by the Langmuir–Freundlich isotherm taking into account the energetic heterogeneity of adsorption system. The effect of temperature and herbicide properties on its uptake was discussed. The thermal analysis was applied in order to find the differences in herbicide interactions with carbon surface. The kinetic dependences were measured and the relations between solute properties and adsorption rate were discussed.

Open access

Abstract

The complexes of rare earth elements with 2,3-naphthalenedicarboxylic acid of the formula: Ln2(C12H6O4)3·nH2O, where Ln = La(III)-Lu(III) and Y(III); n = 3 for La(III), Ce(III); n = 6 for Pr(III)-Yb(III) and Y(III) and n = 5 for Lu(III) have been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis (TG, DTG, DTA and TG-FTIR) and X-ray analysis. They are sparingly soluble in water and stable at room temperature. During heating in air atmosphere, they lose all water molecules in several steps, generally in two or three steps, except for the La(III) and Ce(III) complexes which lose all water molecules in one step. The anhydrous compounds are stable up to about 773 K and then decompose to corresponding oxides. The thermal decomposition is connected with the release of water molecules (443 K), carbon dioxide (713 K) and hydrocarbons.

Open access

. , et al. ( 1985 ), Épületfi zika kézikönyv, Műszaki Könyvkiadó Bp . 389 p. [8] Walton G. N. ( 1985 ), Thermal Analysis Research

Open access

Abstract

In this study, new series of lanthanide 4,4′-oxybis(benzoates) of the general formula Ln2oba3·nH2O, where Ln = lanthanides from La(III) to Lu(III), oba = C12H8O(COO)2 2− and n = 3–6, has been prepared under hydrothermal conditions. The compounds were characterized by elemental analysis, infrared spectroscopy, X-ray diffraction patterns measurements and different methods of thermal analysis (TG, DSC, and TG-FTIR). In addition, photoluminescence properties of the selected complexes have been investigated. Crystalline compounds are isostructural in the whole series. Both carboxylate groups are deprotonated and engaged in the coordination of Ln(III) ions. Heating of the complexes leads to the dehydration and next decomposition processes. Although of the same structure, the removal of water molecules proceeds in different ways. In the nitrogen atmosphere, they decompose releasing water, carbon oxides and phenol molecules. The complexes of Eu(III), Tb(III) and Dy(III) exhibit photoluminescence in the visible range, whereas the compounds of Nd(III) and Yb(III) in the near-infrared region upon excitation by UV light.

Open access

Abstract

The magnesium sulphate complex compounds of general formulae [Mg(H2O)6]2+·2(C6H12N4)·SO4 2−·5(H2O) (1) and Mg(C12H8N2)(H2O)3SO4 (2) have been synthesized, characterised by elemental and thermal analysis, IR, UV–VIS and fluorescence spectroscopy, and X-ray crystallography. The obtained compounds are air stable at room temperature and well soluble in water. In the structures of the investigated complex compounds the O–H…O, O–H…N, and C–H…O hydrogen bonds exist, and they create N2C2 2(8), R2 2(8) (compound 1) and N1C1 1(6), N1R2 2(12) (compound 2) patterns. Their thermal decomposition processes in the investigated atmospheres (air and helium) are different. After the slightly similar dehydratation, the observed transitions and the obtained final products are different (in helium atmosphere the sulphate ion of studied compounds undergoes decomposing what does not take place in air atmosphere). The UV–VIS spectrum of 2 shows maxima that are typical for π π* and nπ* transitions, and fluorescence spectrum of the same compound displays its great fluoresce properties. The 1 does not exhibit absorption in the investigated region of electromagnetic spectrum due to the absence of respect chromophore groups. The IR spectrum of 2 shows typical vibrations for chelating amine molecule. An interesting fact is that in 1 the SO stretching vibrations (existing at 1119 and 1182 cm−1) are doubled in comparison to the magnesium sulphate whilst in 2 these vibrations are absent.

Open access

very important to control the crystal form of the drug during the various stages of drug development, because any phase changes and change in the degree of crystallinity can alter the bioavailability of the drug. Thermal analysis is one of the most

Open access

] Šikula O. , Mohelníková J. , Plášek J. ( 2014 ), Thermal Analysis of Light Pipes for Insulated Flat Roofs . Energy and Buildings . Elsevier B.V . Amsterdam .

Open access