Simulation of the condenser of the seawater greenhouse

A theoretical model is developed in Part I of this study to simulate the physical process of condensation of the humid air in the condenser of an existing seawater greenhouse that is located in Muscat, Oman. Application is conducted in this part to validate the theoretical developments. Comparisons are made between the predictions and the existing experimental results. The results indicate that the comparison is well consistent. The effect of the relative humidity, the dry bulb temperature and the solar radiation are also discussed to see their effects on the condensate values.     

Synthesis and thermal decomposition of bismuth peroxotitanate to Bi2Ti2O7

Bi-peroxotitanate was synthesized by a peroxo method and after thermal decomposition Bi₂Ti₂O₇ was obtained. DTA, TG and DSC curves of Bi₂[Ti₂(O₂)₄(OH)₆]5H₂O were recorded and used to determine isothermal conditions suitable for obtaining the intermediate samples corresponding to the phases observed during the thermal decomposition. The samples were identified by quantitative analysis, IR spectroscopy and X-ray analysis. The experimental results were used to propose a mechanism of thermal decomposition of the investigated compound to a nanosized Bi₂Ti₂O₇. The optimum conditions were also determined for obtaining Bi₂Ti₂O₇, which is applicable for piezosensors.     

Thermal stability of the β″ phase in the ZrO2-Zr3N4 system

Annealing of ZrO₂ in a nitrogen atmosphere leads to a nitrogen containing phase called phase having a trigonally distorted fluorite structure with ordered anion vacancies. DTA/TG investigations indicated that the phase decomposes intom-ZrO₂ above 500C releasing nitrogen during the reaction with oxygen. Prevention of oxygen uptake by use of closed tantalum tubes instead of open platinum crucibles enabled the detection of a new reversible phase transition at 965C. The thermoanalytical results have been confirmed by high temperature-X-ray investigation.Dedicated to Professor Dr. Roger Blachnik on the occasion of his 60^th birthday     

Subsolidus area of the system CdO - V2O5 - Fe2O3

Phase diagrams in the subsolidus area of the systems FeVO₄ - CdO and FeVO₄ - Cd₂V₂O₇ have been deduced using the results of XRD and DTA analyses. On the basis of these diagrams and some additional verifying research, a projection of the subsolidus area of the CdO - V₂O₅ - Fe₂O₃ system onto the plane that comprises the components’ concentration triangle has been presented. The H-type phase is the only phase formed in this system. It co-exists at equilibrium with other phases in six subsidiary subsystems.      

Properties of the wastes produced in the semi-dry FGD installation

In this paper the examination results of chemical and phase composition as well as wastes graining from the semi-dry flue gas desulfurization (FGD) have been presented. The wastes contain mainly semi-hydrate calcium sulfite and calcium sulfate. The phase composition changes of wastes at the temperature of 350 and 600°C have been determined. On the basis of carried out examinations, possibilities of flue gas desulfurization wastes utilization in building materials production (sulfite and anhydrite cement) are proposed.     

Thermoanalytical methods in the study of inorganic thin films

Thermoanalytical (TA) methods are relatively seldom applied for assessing the physical and chemical proeprties of thin films, but they can be used in studies of composition, phase transitions and film—substrate interactions. In the present paper the possibilities of TA methods in thin film studies are reviewed. The thermoanalytical methods considered are the classical TG and DTA/DSC methods but some complementary methods will also be briefly mentioned. The main emphasis is given to true thin films. Details of sample preparation are also given. An important application of TA methods is characterization of precursors for the CVD growth of thin films, and this is also discussed.     

Application of thermal analysis in a phase composition study on by-product from semi-dry flue gas desulfurization system

DTA, TG and XRD methods were used for the determination of by-product - obtained during flue gas desulfurization by means of introduction of dehydration - resisting sludge from water decarbonization system. Analysis results enabled the development and application of sludge utilization technology by means of semi-dry flue gas desulfurization in 'Siersza' power plant. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal properties of high-T c superconductors

The termal stabilities of several families of high-T _c superconductors (HTSC), as well as the dependence of phase transitions on temperature and stoichiometry, have been studied by X-ray diffraction, DTA, TG and DSC. Experimental results are discussed in the context of decomposition models.     

水热处理氢氧化镁微晶性质研究

Shape apprearance and crystallite characterization of magnesium hydroxide at different hydrothermal tempera-tures have been investigated by SEM， XRD and DSC methods. The grain size， cell parameter and lattice distortion rate of powders under each condition were obtained. The results show that the grains had grown up， especially along the (001) surface as the hydrothermal temperature was raised， accompanying the shrinkage of lattice and the de-scending of distortion rate. These could be relate to the re-crystallization of Mg(OH)₂， as well as the thermal dif-fusion of OH^- with lower charges， resulting in good dispersion， high thermal decomposition temperature and en-thalpy of Mg(OH)₂. Moreover， it is helpful for the increase of the retardant behavior of Mg(OH)₂.     

The Mechanism of the Thermal Transformation From Goethite to Hematite

Synthetic pigments of goethite (Bayferrox^R) of different particle size were investigated by DTA, IR, DSC, TG and X-ray diffraction measurements. It follows that a so-called ‘hydrohematite’ described in the literature does not exist as a discrete intermediate during the dehydration course from goethite to hematite. Instead we observed a dependence of the dehydration mechanism on the particle size. Transformation enthalpies and activation energies for the dehydration process will be given. A plausible dehydration mechanism, which is compatible with our DTA/DSC results, is deduced from TEM investigations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Phase Equilibria in the Fe8V10W16O85-Fe2O3 and Fe8V10W16O85-Fe2WO6 Systems

Using DTA and X-ray phase diffraction methods, a diagram of phase equilibria established in two sections of a tricomponent oxide triangle Fe₂O₃-V₂O₅-WO₃was constructed, that is, in the sections: Fe₈V₁₀W₁₆O₈₅-Fe₂O₃and Fe₈V₁₀W₁₆O₈₅-Fe₂WO₆. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and Thermal Stability of Zn4V2O9

A study of synthesis and thermal decomposition of the Zn₄V₂O₉ have been conducted by XRD method using a high-temperature X-ray attachment. A melting temperature and the way of melting that compound have been established. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal analysis of gel-derived support for metallic catalyst

A series of Al₂O₃-SnO₂ catalysts with the molar ratio of Al₂O₃ to SnO₂ between 1:0 and 0:1 have been characterized by thermal analysis in reductive conditions, TPR and XRD methods. In the reductive conditions in temperatures up to about 1000 K, no reduction of the tin component to the metallic form takes place in the binary gel Al₂O₃-SnO₂. In the temperatures characteristic of the reforming process, only a reduction to SnO occurs in the above binary support. Thermal analysis of the gels in the reductive conditions and TPR results indicate stabilisation of the tin oxide species even in the systems of the molar ratio of Al₂O₃ to SnO₂ of 1:1. The metallic tin appears in the binary gel only after its reduction in the hydrogen atmosphere at temperatures close to ∼1100 K.     

Synthesis of Solid Solutions in the (1-x)PbZrO3-xK0.5Bi0.5TiO3 System

DTA, TG, XRD and IR methods were used to study the formation of solid solutions in the selected subsolidus range of the PbZrO₃-K_0.5Bi_0.5TiO₃ system by heating mixtures prepared using oxide substrates, i.e. PbO, Bi₂O₃, ZrO₂, TiO₂ and K₂CO₃. It was found that solid solutions are formed in the reaction of PbO and ZrO₂ with intermediate compound, i.e. K_0.5Bi_0.5TiO₃. PbZrO₃ was not found to be formed as an intermediate phase. This revised version was published online in August 2006 with corrections to the Cover Date.     

Study on Phase Relations in Zn3V2O8–ZnMoO4 System

The phase equlibria established in the Zn₃V₂O₈–ZnMoO₄ system over the whole component concentration range up to 1000°C have been investigated. A phase diagram has been constructed using the results of DTA and XRD methods. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase Relations in The V2O5–MoO3–α-Sb2O4 System in The Solid State in Air Atmosphere

The phase equilibria established in the V₂O₅–MoO₃–α-Sb₂O₄ system in the solid state in an air atmosphere were examined by using XRD and DTA methods. The obtained results allowed us to find that in this system a novel compound is formed involving three oxides. Its formula can be written as Sb₃V₂Mo₃O₂₁. The synthesis of this compound requires picking up the atmospheric oxygen. X-ray characteristics of this compound were determined and it was found that it melted incongruently at 740°C. The results obtained until now allow us to divide the investigated V₂O₅–MoO₃–α-Sb₂O₄ system into five partial subsystems. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reactivity in Air of SbVO5 Towards MoO3 and Phase Equilibria in the SbVO5–MoO3 System in the Solid State

The use of XRD and DTA methods has allowed studies on the interaction of the SbVO₅ and MoO₃, taking place in the solid state and in the medium of ambient air. The experimental results of XRD and DTA for all the samples showed the presence of a novel phase, i.e. Sb₃V₂Mo₃O₂₁ apart from various amounts of MoO₃ and V₉Mo₆O₄₀ or SbVO₅ and V₂O_5(s.s.). The SbVO₅–MoO₃ system is not a real two-component system over the entire range of component concentrations up to the solidus line. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase diagrams for the YBa2Cu3O7 family — ANNO 1996

Phase diagrams for cuprates of alkaline earth and rare earth elements are presented, covering binary to quintenary oxides and including selected solid solution series with other elements. Elementary crystal chemical data are included for identification of the occurring phases. Chemical stability is discussed with respect to the high-temperature reactions with Lewis acids like CO₂, protons, etc. Particularly the occurrence of oxide carbonates is consistently pointed out as one of the possible reasons for contradictory results in phase diagrams which comprise oxides with high basicity.     

Reinvestigation of Phase Equilibria in the V2O5–ZnO System

A diagram of phase equilibria established in a two-component oxide system V_{2 5}–ZnO has been worked out applying differential thermal analysis and X-ray phase analysis as well as depending on investigations carried out with the aid of high-temperature X-ray attachment and scanning electron microscope linked to an X-ray microanalyser. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase Transition and Thermal Decomposition of [Cd(H2O)6](BF4)2

Phase transition and thermal decomposition of [Cd(H₂O)₆](BF₄)₂ were studied by differential scanning calorimetry (DSC), differential thermal analysis (DTA) and thermogravimetry (TG) methods. The solid-solid phase transition at T _C1=324 K and the melting point atT _melt.=391 K were registered. The thermal dehydration process starts just above T _C1 and continues up to T _melt.,where [Cd(H₂O)₄](BF₄)₂ in the liquid phase is formed. Then, dehydration and decomposition take place simultaneously until CdF₂ is obtained. Final products of the thermal decomposition were identified using quadrupole mass spectrometry (QMS) and X-ray diffraction methods. This revised version was published online in August 2006 with corrections to the Cover Date.