Heat of Fusion of Na3AlF6 Eutectic Mixtures with CaF2 and Al2O3

The heat of fusion of eutectic mixtures of sodium cryolite with alumina and calcium fluoride was measured using differential scanning calorimetry. Melting temperatures were found to be in good agreement with literature data. The molar heat of fusion of cryolite salts and eutectic mixtures was found to be directly dependent on melting temperature. The temperature dependence coefficient is the same as that of alkali halides

Novel Molten Salts Media For Production of Functional Materials

Physical-chemical properties of molten salt media based on potassium cryolite with additions of boron or scandium oxides have been considered from the point of view of their feasibility in production of functional materials, such as aluminum alloys. Liquidus temperature in the quasi-binary systems: [KF–AlF3]-B2O3, [KF–AlF3]-Sc2O3, [KF–NaF–AlF3]-B2O3, and [KF–NaF–AlF3]-Sc2O3 has been measured by thermal analysis. Solubility of Al2O3, B2O3, and Sc2O3 in potassium and potassium-sodium cryolites has been determined. The potassium-cryolite-based melts were found to have an enhance protective function due to a low melting point, and an effective refining ability due to a good alumina solubility. It has been assumed that for aluminum alloys production the potassium-cryolite-based melts can be used as fluxes with improved properties as well as electrolytes for low-temperature electrolysis

Using Emotional Markers' Frequencies in Stock Market ARMAX-GARCH Model

We analyze the possibility of improving the prediction of stock market indicators by adding information about public mood expressed in Twitter posts. To estimate public mood, we analysed frequencies of 175 emotional markers - words, emoticons, acronyms and abbreviations - in more than two billion tweets collected via Twitter API over a period from 13.02.2013 to 22.04.2015. We explored the Granger causality relations between stock market returns of S&P500, DJIA, Apple, Google, Facebook, P zer and Exxon Mobil and emotional markers frequencies. We found that 17 emotional markers out of 175 are Granger causes of changes in returns without reverse e ect. These frequencies were tested by Bayes Information Criteria to determine whether they provide additional information to the baseline ARMAX-GARCH model. We found Twitter data can provide additional information and managed to improve prediction as compared to a model based solely on emotional markers

Using Emotional Markers' Frequencies in Stock Market ARMAX-GARCH Model

We analyze the possibility of improving the prediction of stock market indicators by adding information about public mood expressed in Twitter posts. To estimate public mood, we analysed frequencies of 175 emotional markers - words, emoticons, acronyms and abbreviations - in more than two billion tweets collected via Twitter API over a period from 13.02.2013 to 22.04.2015. We explored the Granger causality relations between stock market returns of S&P500, DJIA, Apple, Google, Facebook, P zer and Exxon Mobil and emotional markers frequencies. We found that 17 emotional markers out of 175 are Granger causes of changes in returns without reverse e ect. These frequencies were tested by Bayes Information Criteria to determine whether they provide additional information to the baseline ARMAX-GARCH model. We found Twitter data can provide additional information and managed to improve prediction as compared to a model based solely on emotional markers

Novel Molten Salts Media For Production of Functional Materials

Physical-chemical properties of molten salt media based on potassium cryolite with additions of boron or scandium oxides have been considered from the point of view of their feasibility in production of functional materials, such as aluminum alloys. Liquidus temperature in the quasi-binary systems: [KF–AlF3]-B2O3, [KF–AlF3]-Sc2O3, [KF–NaF–AlF3]-B2O3, and [KF–NaF–AlF3]-Sc2O3 has been measured by thermal analysis. Solubility of Al2O3, B2O3, and Sc2O3 in potassium and potassium-sodium cryolites has been determined. The potassium-cryolite-based melts were found to have an enhance protective function due to a low melting point, and an effective refining ability due to a good alumina solubility. It has been assumed that for aluminum alloys production the potassium-cryolite-based melts can be used as fluxes with improved properties as well as electrolytes for low-temperature electrolysis

Phase transitions and thermal expansion of cryolite based eutectic mixture in solid state

Были исследованы некоторые эвтектические смеси криолита натрия с Al[2]O[3] и CaF[2], а также некоторые легкоплавкие эвтектические смеси. Полученные результаты показывают несколько точек перехода для смесей на основе криолита натрия

Thermal Conductivity of FLiNaK in a Molten State

Although the thermal conductivity of molten salt mixtures is of interest for many potential technological applications, precise values are often hard to obtain. In this study, the thermal diffusivity of FliNaK was studied in a molten state using the laser flash method and found to be very slightly dependent on temperature. The heat capacity of FliNaK was measured using the DSC method. There was a minor difference between our results and data from the literature. From calculations based on thermal diffusivity, density and heat capacity values, thermal conductivity was shown to decrease with temperature

Thermal Properties of Li₂BeF₄ near Melting Point

The LiF–BeF2 system is used as a heat transfer medium in molten salt reactors (MSRs). The thermal diffusivity of Li2BeF4 was studied using the laser flash analysis (LFA) method in solid and transition states. While the thermal diffusivity is shown to decrease slightly in solid-state Li2BeF4, it drops significantly at temperatures close to phase transition. The heat capacity of Li2BeF4 was measured by differential scanning calorimetry (DSC). Some differences were observed between the results obtained in cooling and heating modes. Thermal conductivity was calculated using thermal diffusivity-, density-, and heat-capacity data. The good thermal conductivity of the Li2BeF4 compound in solid and liquid states justifies its use as a heat transfer medium for molten salt reactors