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Tato bakalářská práce se zaměřuje na studium fosforečnanových skel s antimonem, která se zdají být vhodná pro aplikace v optoelektronických zařízeních. Přídavek antimonu do skloviny může ovlivnit její strukturu, mechanické vlastnosti a optické charakteristiky. Vliv rostoucího obsahu antimonu na strukturu binárních fosforečnanových skel systému xSb2O3-(1-x)P2O5, kde x = 25, 30, 35, 40, byl studován pomocí nukleární magnetické rezonance a Ramanovy spektroskopie., This bachelor thesis focuses on the study of phosphate glasses with antimony, which seem to be suitable for applications in optoelectronic devices. The addition of antimony to the glass can affect its structure, mechanical properties and optical characteristics. The effect of increasing antimony content on the structure of binary phosphate glasses of the system xSb2O3-(1-x)P2O5, where x = 25, 30, 35, 40, was studied by nuclear magnetic resonance and Raman spectroscopy., Fakulta chemicko-technologická, Student seznámil komisi se svojí bakalářskou prací. Zodpověděl otázky členů komise: Jak byly vypočteny molární hmotnosti připravených materiálů? Jaká byla chyba stanovení Tg? Které z použitých metod jste provedl sám? Osvětlete metodu MAS NMR.  Jakým způsobem byl stanoven koeficient α připravených vzorků? Jaká je přesnost použité metody XRF? Na kolika místech vzorku byla metoda XRF použita? Co je to Faradayův rotátor? &nbsp, Dokončená práce s úspěšnou obhajobou

Densities of fifteen aqueous solutions of sulfuric acid (H₂SO₄) have been measured by vibrating-tube densimetry at solute molalities (m) from (0.01 to 3.0) mol·kg⁻¹ over the temperature range 293.15 ≤ T/K ≤ 343.15. These data have been used to calculate the corresponding apparent molar volumes Vϕ(H₂SO₄,aq), which represent a significant expansion of the volumetric database for this industrially-important acid. At 298.15 K the present results agree well with literature data, notably with the century-old values given in the 1926 International Critical Tables. At other temperatures, where comparisons are possible agreement with the present Vϕ values is also very satisfactory. Consistent with earlier studies, Vϕ(H₂SO₄,aq) was found to exhibit an abnormally-large decrease at low concentrations (m ≤ 0.1 mol·kg⁻¹). This effect is consistent with a change in the chemical speciation of H₂SO₄(aq), from an essentially 1:1 electrolyte (H⁺(aq) + HSO₄− (aq)) at higher concentrations to a predominantly 1:2 electrolyte (2H⁺(aq) + SO₄²⁻ (aq)) in dilute solutions. The Vϕ values were modelled using variants of Young’s rule and the Pitzer formalism. Combination of these results with literature values for the standard volume V°(SO₄²⁻,aq) enabled estimation of V°(HSO₄−,aq) and the standard volume change, ΔrV°, for the first protonation of the sulfate ion (H⁺(aq) + SO₄²⁻(aq) → HSO₄−(aq)) as functions of temperature. It is shown that V°(HSO₄−,aq) is sensitive to the value of the first protonation constant and probably cannot be determined to better than ± 0.3 cm³·mol⁻¹ at present.

The roomerature molar volumes of bcc (β), hcp (equilibrium α or martensitic α′), and orthorhombic (martensitic α′′) phases are modeled for a number of Ti-base solid solutions in the CALPHAD framework. The martensitic molar volume is continuous at the α′/α′′ transition composition. Hcp and orthorhombic structures are modeled separately, and the predicted martensitic structure is taken as the denser one., QC 20160129

Mossbauer Effect (ME) and Infrared (IR) spectroscopes are used to study the structure of some iron-sodium phosphate glasses containing strontium, with composition [(70-x) mol% P2O5. x mol% SrO, 15 mol% Fe2O3.15 mol% Na2O, where x= 3, 6,9,12 and 15]. These glasses can have many interesting applications especially as gamma ray attenuators. The amorphous nature and the glassy state character of these glasses can be confirmed from comparing the experimental and empirical values of both their density and molar volume. It was found that, as SrO was gradually increased the density increased while the molar volume decreased which may be due to the gradual decrease of the number of oxygen ion density in the glass networks. The micro-hardness and magnetic susceptibility are also increased, which can be attributed to the gradual migration of iron from glass network modifier (GNM) to glass network former (GNF) positions, as confirmed by IR and ME results. IR and ME analysis indicated that both ferric and ferrous have tetrahedral and octahedral symmetry respectively and acting as GNF and GNM at different SrO contents. The gradual replacement of P2 O5 by SrO force the iron to transfer from GNM to GNF. The gamma-ray mass attenuation coefficient increased with the gradual increase of Sr2+ as heavy metal, while the HVL decreased. On the other hand the attenuation coefficient decreased with the increase of gamma-ray photon energy. So, these glasses can be used as transparent shielding materials for low gamma-ray energies and to capsulate the radio-active wastes, while the sample containing 15 mol% SrO, exhibits the highest attenuation coefficient.

Mossbauer Effect (ME) and Infrared (IR) spectroscopes are used to study the structure of some iron-sodium phosphate glasses containing strontium, with composition [(70-x) mol% P2O5. x mol% SrO, 15 mol% Fe2O3.15 mol% Na2O, where x= 3, 6,9,12 and 15]. These glasses can have many interesting applications especially as gamma ray attenuators. The amorphous nature and the glassy state character of these glasses can be confirmed from comparing the experimental and empirical values of both their density and molar volume. It was found that, as SrO was gradually increased the density increased while the molar volume decreased which may be due to the gradual decrease of the number of oxygen ion density in the glass networks. The micro-hardness and magnetic susceptibility are also increased, which can be attributed to the gradual migration of iron from glass network modifier (GNM) to glass network former (GNF) positions, as confirmed by IR and ME results. IR and ME analysis indicated that both ferric and ferrous have tetrahedral and octahedral symmetry respectively and acting as GNF and GNM at different SrO contents. The gradual replacement of P2 O5 by SrO force the iron to transfer from GNM to GNF. The gamma-ray mass attenuation coefficient increased with the gradual increase of Sr2+ as heavy metal, while the HVL decreased. On the other hand the attenuation coefficient decreased with the increase of gamma-ray photon energy. So, these glasses can be used as transparent shielding materials for low gamma-ray energies and to capsulate the radio-active wastes, while the sample containing 15 mol% SrO, exhibits the highest attenuation coefficient.

A theoretical analysis of the proposed insensitive high energy density material (IHEDM) 2-aza-3- dinitromethylene-4-azanitro bicyclo [3.3 .0]-7-nitro-6,8-diazole (ADAND) is reported. A Density Functional Theory (DFT) study is performed in order to determine the optimized structure and stability as well as thermochemical aspects of ADAND. All calculations were performed using the Gaussian03 software with the Gaussview graphical user interface. Normal modes of vibration and heat of detonation of the proposed insensitive energetic material are calculated; the oxygen balance and energy density of the proposed IHEDM are also determined. Calculations were also performed on FOX-7; 2,4-dinitroimidazole (2,4-DNI); RDX ; 2- methyl-4,5-dinitro-l,2,3-triazole-2-oxide (MDNTO); and HMX to enable comparison of the chosen explosive performance parameters to ADAND.

In an attempt to estimate the densities of complex slags, a model based on the thermodynamics ofslags developed earlier by the present authors is extended to ternary and multi-component systemsin the present work. The molar volumes of ternary and higher order systems were derived from therelative integral molar enthalpies of mixing of the corresponding slags. The higher order of slagsystems has been predicted by using the parameters from the related binary sub-systems, whichhave been evaluated earlier. Comparisons of calculated results with experimental data on molarvolumes available in literature show a satisfying agreement for a number of systems, within the limitsof experimental uncertainties. The model presents a promising method to compute the molar volumeof slag systems where no experimental data is available using the abundance of thermodynamicdata available. The model would also enable the generation of density data for slags containingAl2O3, CaO, FeO, MgO, MnO, and SiO2 compatible with the corresponding thermodynamic data., QC 20100812

In an effort to interlink the thermo chemical and thermo physical properties of slags, the present work was undertaken to derive the molar volumes of complex slags from the enthalpies of mixing of the corresponding slags. As a first step, binary systems of the following oxides were investigated; Al2O3, CaO, FeO, MgO, MnO, and SiO2. An empirical correlation was derived between the enthalpies of mixing and molar volumes. A comparison of the computed results on the basis of the above relationship with the experimental data on molar volumes available in literature shows that the agreement between the calculated results and measured densities is satisfactory in the case of most of the binary systems, within the limits of experimentally uncertainties. The advantage of the present approach is that it would enable prediction of molar volumes of slags that are compatible with the thermodynamic data available., QC 20100525

The production of high quality castings requires the casting surface to be clean and free from defects. One type of defect often found is caused by metal penetration into the sand mould. Metal penetration is a casting surface condition resulting from either physical, mechanical and/or thermochemical reactions or a combination of these at the mould–metal interface. The metal penetrates into the voids between the sand grains to various depths without displacing the grains, thus yielding a phase of sand grains surrounded by metal and frequently by mould-metal reaction products. The present work is devoted to investigating the mechanisms of metal expansion penetration during solidification of grey cast iron. The phenomenon of metal expansion penetration has been examined experimentally. A series of test castings were produced at two foundries, to study the influence of chemical composition, the casting temperature and the addition of inoculants with respect to both primary and eutectic phases. The experiments show that the type and amount of inoculant, the casting temperature and the chemical composition influence the metal expansion penetration. Two major types of metal expansion penetration mechanisms are suggested with respect to the nucleation and growth of the primary and eutectic phases. The expansion penetration mechanisms found in the experimental work were also identified on complex shaped industrial castings such as clutch components and cylinder heads. The entire casting process was simulated using commercial software, and in which nucleation and growth of all relevant phases was considered in order to investigate the solidification characteristics and porosity formation in the casting. A good correlation between the simulation and experiments on real castings was found. Density and volume change in grey cast iron seem to play a decisive roll in the occurrence of metal expansion penetration. Laboratory measurements of density variations are difficult. A novel

The production of high quality castings requires the casting surface to be clean and free from defects. One type of defect often found is caused by metal penetration into the sand mould. Metal penetration is a casting surface condition resulting from either physical, mechanical and/or thermochemical reactions or a combination of these at the mould–metal interface. The metal penetrates into the voids between the sand grains to various depths without displacing the grains, thus yielding a phase of sand grains surrounded by metal and frequently by mould-metal reaction products. The present work is devoted to investigating the mechanisms of metal expansion penetration during solidification of grey cast iron. The phenomenon of metal expansion penetration has been examined experimentally. A series of test castings were produced at two foundries, to study the influence of chemical composition, the casting temperature and the addition of inoculants with respect to both primary and eutectic phases. The experiments show that the type and amount of inoculant, the casting temperature and the chemical composition influence the metal expansion penetration. Two major types of metal expansion penetration mechanisms are suggested with respect to the nucleation and growth of the primary and eutectic phases. The expansion penetration mechanisms found in the experimental work were also identified on complex shaped industrial castings such as clutch components and cylinder heads. The entire casting process was simulated using commercial software, and in which nucleation and growth of all relevant phases was considered in order to investigate the solidification characteristics and porosity formation in the casting. A good correlation between the simulation and experiments on real castings was found. Density and volume change in grey cast iron seem to play a decisive roll in the occurrence of metal expansion penetration. Laboratory measurements of density variations are difficult. A novel

The production of high quality castings requires the casting surface to be clean and free from defects. One type of defect often found is caused by metal penetration into the sand mould. Metal penetration is a casting surface condition resulting from either physical, mechanical and/or thermochemical reactions or a combination of these at the mould–metal interface. The metal penetrates into the voids between the sand grains to various depths without displacing the grains, thus yielding a phase of sand grains surrounded by metal and frequently by mould-metal reaction products. The present work is devoted to investigating the mechanisms of metal expansion penetration during solidification of grey cast iron. The phenomenon of metal expansion penetration has been examined experimentally. A series of test castings were produced at two foundries, to study the influence of chemical composition, the casting temperature and the addition of inoculants with respect to both primary and eutectic phases. The experiments show that the type and amount of inoculant, the casting temperature and the chemical composition influence the metal expansion penetration. Two major types of metal expansion penetration mechanisms are suggested with respect to the nucleation and growth of the primary and eutectic phases. The expansion penetration mechanisms found in the experimental work were also identified on complex shaped industrial castings such as clutch components and cylinder heads. The entire casting process was simulated using commercial software, and in which nucleation and growth of all relevant phases was considered in order to investigate the solidification characteristics and porosity formation in the casting. A good correlation between the simulation and experiments on real castings was found. Density and volume change in grey cast iron seem to play a decisive roll in the occurrence of metal expansion penetration. Laboratory measurements of density variations are difficult. A novel

The molar volumes and thermal expansions of transition cubic metals were studied by means of the Calphad approach and the Debye-Gruneisen model. Experimental data were collected and assessed using Calphad procedures, and consistent results were obtained which give the best description of all experimental data. In order to put the prediction of the thermodynamic properties of metastable phases on a sound physical basis, the Debye-Gruneisen model was chosen to account for the vibrational contribution and calculate the coefficients of linear thermal expansion (CLEs) of stable cubic metals. Two approximations for Gruneisen parameter gamma, i.e. Slater ' s and Dugdale and MacDonald ' s expressions were adopted. A modified calculation scheme, first proposed by Wang et al., was derived in a straightforward way and used to evaluate the Debye temperature from ab initio electronic total-energy calculations at T = 0 K. The thermal electronic contribution to CLE was also evaluated from the electronic density of states. The calculated total CLEs were compared with those from the Calphad assessments. A satisfactory agreement is reached., QC 20101004

The molar volume and thermal expansion of selected metallic elements with the bcc, fcc and hcp structures were studied by means of the Calphad approach. Experimental data were critically assessed, and model parameters were obtained yielding reasonable descriptions of all experimental data on molar volume and thermal expansion. The descriptions are valid between room temperature and the melting points at atmospheric pressure., QC 20100831 Uppdaterad från In press till Published (20108831)

The objective is to improve thermal expansion, specific heat, molar volume, and bulk moduli predictions at the highest temperatures and pressures. In those regions experiments are difficult and data is often marginally reliable. In a series of papers, we have developed models for predicting these properties for a wide range of metals, ceramics and semiconductors. By considering the influence of thermal defects on thermal expansion it has been possible to provide a quantitative relationship for thermal expansion and molar volume from near absolute zero to the melting point for refractory metals aluminum and copper. Over the course of the project we have combined our improved properties with finite element methods to calculate residual stresses important for the fabrication and reliability of group Ill-V Nitride devices and tungsten carbide.

The meta! expansion penetration has been examined experimentally. The whole casting process was simulated using a commercial software, in order to investigate the solidification characteristics and the pore formation in the casting studied. In order to do this, a special module for cast iron was used, where nucleation and growth of all relevant phases are considered. During simulation it is possible to detect the areas where porosities are likely to be formed. The results of the experiments show that expansion penetration generally occurs in the same areas as detected in the simulation depending on the solidification path. The inoculation and solidification behaviour will result in an excess or deficiency of meta! at the end of solidification. This will lead to either meta! penetration or the formation of pores. A series of test castings were produced at a foundry. They were used to study the influence of chemical composition, the type and amount of inoculant and the casting temperature. The results show that the carbon and phosphorus content had an influence on meta! penetration. The tendency for meta! penetration decreased whit decreasing carbon content as well as with increasing phosphorus content. The experiments show that the type and amount of inoculant and casting temperature for grey cast iron influence the meta! expansion penetration in areas with late solidification and where the melt is in contact with the sand mould. The worst cases of meta! penetration were obtained with uninoculated melt. A !arge number of small eutectic cells making up a !arge fraction of the volume were observed, resulting in a !arge penetration.

The meta! expansion penetration has been examined experimentally. The whole casting process was simulated using a commercial software, in order to investigate the solidification characteristics and the pore formation in the casting studied. In order to do this, a special module for cast iron was used, where nucleation and growth of all relevant phases are considered. During simulation it is possible to detect the areas where porosities are likely to be formed. The results of the experiments show that expansion penetration generally occurs in the same areas as detected in the simulation depending on the solidification path. The inoculation and solidification behaviour will result in an excess or deficiency of meta! at the end of solidification. This will lead to either meta! penetration or the formation of pores. A series of test castings were produced at a foundry. They were used to study the influence of chemical composition, the type and amount of inoculant and the casting temperature. The results show that the carbon and phosphorus content had an influence on meta! penetration. The tendency for meta! penetration decreased whit decreasing carbon content as well as with increasing phosphorus content. The experiments show that the type and amount of inoculant and casting temperature for grey cast iron influence the meta! expansion penetration in areas with late solidification and where the melt is in contact with the sand mould. The worst cases of meta! penetration were obtained with uninoculated melt. A !arge number of small eutectic cells making up a !arge fraction of the volume were observed, resulting in a !arge penetration.

The meta! expansion penetration has been examined experimentally. The whole casting process was simulated using a commercial software, in order to investigate the solidification characteristics and the pore formation in the casting studied. In order to do this, a special module for cast iron was used, where nucleation and growth of all relevant phases are considered. During simulation it is possible to detect the areas where porosities are likely to be formed. The results of the experiments show that expansion penetration generally occurs in the same areas as detected in the simulation depending on the solidification path. The inoculation and solidification behaviour will result in an excess or deficiency of meta! at the end of solidification. This will lead to either meta! penetration or the formation of pores. A series of test castings were produced at a foundry. They were used to study the influence of chemical composition, the type and amount of inoculant and the casting temperature. The results show that the carbon and phosphorus content had an influence on meta! penetration. The tendency for meta! penetration decreased whit decreasing carbon content as well as with increasing phosphorus content. The experiments show that the type and amount of inoculant and casting temperature for grey cast iron influence the meta! expansion penetration in areas with late solidification and where the melt is in contact with the sand mould. The worst cases of meta! penetration were obtained with uninoculated melt. A !arge number of small eutectic cells making up a !arge fraction of the volume were observed, resulting in a !arge penetration.

A review is made of measurements of the effect of temperature, pressure, isotopic composition, and dissolved atmospheric gases on the density of liquid water at temperatures to 100 deg. C. The molar volume is expanded as a multiple power series in the variables, and the coefficients determined. A number of gaps become evident in our knowledge of properties that are within the capacity of current measurements. For example, there appears to be no measurement of the effect of oxygen isotopes on the compressibility. Data on the thermal expansion of D2O are strikingly inconsistent. The partial molar volumes of dissolved gases are only sketchily known. At O deg. C, equilibration with the oxygen, nitrogen, and argon of the atmosphere lowers the density about 3 p.p.m., while atmospheric carbon dioxide raises it about 0.3 p.p.m. Appendix I discusses the care needed to obtain various degrees of precision in practical density measurements, and the effect of isotopic uncertainties on them. Appendix II treats the representation of the equation of state of water at slightly higher pressures. (Author), Reprint no. 104 from Jnl. of Physical and Chemical Reference Data, v6 n4 p1109-1131 1977.

The values of partial molar volume (PMV) of ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate were determined in twelve n-donor solvents and compared with the known values of PMVs of lithium and magnesium perchlorates in the same solvents. The proportionality in the change in the molar volumes of these salts and the predominant contribution of anion solvation were observed. The values of PMVs of the 1-butyl-3-methylimidazolium cation were calculated. © 2012 Springer Science+Business Media New York.

The method of penetrating gamma-radiation was used to measure the density of copper-aluminum melts containing from 0 to 100 % aluminum in the range of temperatures from liquidus to 1300-1400 A degrees C; the concentration dependences of their molar volume were calculated as well. High accuracy of measurements (error not exceeding 0.2 %) allows using the values as reference data. Substantial non-monotonicity of the molar volume isotherms that proves the complexity of the specified melts especially in the area of compositions rich in aluminum was found. The parameters of polynomials describing concentration dependencies of the molar volume with the error not exceeding 1 % are presented.

The values of partial molar volume (PMV) of ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate were determined in twelve n-donor solvents and compared with the known values of PMVs of lithium and magnesium perchlorates in the same solvents. The proportionality in the change in the molar volumes of these salts and the predominant contribution of anion solvation were observed. The values of PMVs of the 1-butyl-3-methylimidazolium cation were calculated. © 2012 Springer Science+Business Media New York.

The surface tensions and the molar volumes of liquid GaBi, Ga-Sn, Ga-In, Sn-Bi, In-Bi and Sn-In binary alloys, and liquid Ga-Bi-Sn and Ga-Bi-In ternary alloys have been measured at 873 K by the sessile drop method. In addition, the calculation of the surface tension of the above binary alloys has been carried out to interpret the composition dependences of the surface tension of Ga-base liquid alloys from the thermodynamic point of view.

The surface tensions and the molar volumes of liquid GaBi, Ga-Sn, Ga-In, Sn-Bi, In-Bi and Sn-In binary alloys, and liquid Ga-Bi-Sn and Ga-Bi-In ternary alloys have been measured at 873 K by the sessile drop method. In addition, the calculation of the surface tension of the above binary alloys has been carried out to interpret the composition dependences of the surface tension of Ga-base liquid alloys from the thermodynamic point of view.