Papers by Keyword: Solubility

Abstract: This paper describes a method for detecting defects inside high-refractive index gems. This method consists in immersion of a precious stone inside low-melting chalcogenide glass. After cooling, molten glass turns into a solid phase and is an optical cube. This cube can be photographed in layers and using OctoNus equimpment a 3D model of gemstone defects can be built. The proposed method allows you to effectively and accurately determine the coordinates of the defects in diamond and to offer the most profitable option for polishing a precious stone.

Abstract: The study of glass components influence on the physical and chemical properties of As–S–Se–I glasses has the potential to help design glasses with the required properties. A change of certain glass properties upon the introduction of selenium into AsSI glass was demonstrated. Non-stoichiometric compounds along the As₂S₃-AsI₃-Se diagram section were investigated by differential thermal analysis, ultrasonic measurements, dilatometric measurements. It has been shown that the introduction of selenium decreases the glass solubility in water. Change in the glass properties with the change in the short-range structure studied by Raman spectroscopy was shown. These glasses can be used for creation of immersion lenses and optical adhesives which change radiation characteristics of mid-IR LEDs.

Abstract: The reheat furnace process step has a profound effect on the TMCP performance, final hot rolled steel quality and mechanical property consistency during the production of hot rolled steels. The uniformity of heating applied across the entire width and length of the slab or billet is critical in the achievement of customer properties regardless of the chemistry. The resultant ferrite grain size in the final hot rolled product is significantly governed by the initial prior austenite grain size. Numerous reheat furnace process metallurgy and combustion parameters in actual operation affect mill productivity, microstructure, austenite grain size, scrap rate and diverts. This reheating step in the steelmaking process often receives low priority in the evaluation of product quality and mechanical property performance, especially the toughness through the plate thickness. Heat transfer conditions of radiation, convection and conduction affect furnace heating efficiency. In laboratory studies, the furnace heating step is typically quite uniform resulting in a homogeneous and fine prior austenite grain size. During production, it is much more difficult to control the uniformity of heating and heat transfer consistency along the entire length and through the thickness of the work piece. The furnace conditions are correlated to product quality via furnace process variables such as the air to gas ratio, furnace burner condition, furnace pressure, energy efficiency, adiabatic flame temperature (AFT) and furnace refractory condition. Operational practice recommendations are presented to minimize inhomogeneous heating which results in inferior product quality, hot rolling model anomalies and toughness variations in the through-thickness-direction.

Abstract: High density MgAl₂O₄/YAG (yttrium aluminum garnet) eutectic composites were successfully prepared by in-situ reaction sintering using induction heating (IH). The effects of IH time and the starting materials composition on the phase composition and microstructure were investigated. The results showed that the eutectic composites consisted of only MgAl₂O₄ and YAG phase could be prepared by IH in a short time in a range of Al₂O₃/MgO ratio between 1~1.54. Compared to conventional sintering (CS), the solubility of Al₂O₃ in spinel is remarkably enhanced under the synergistic effects of high temperature and induced electromagnetic field. The higher YAG content facilitates the formation of more eutectic liquid phase, which favors to obtain a more homogeneous and denser interpenetrating network structure.

Abstract: Four tropine-based ionic liquids with the anion of PF6^-were synthesized and their hydrophilicity/hydrophobicity was evaluated according to the solubility determination in water. Then the empirical equation model, the λh model, the NRTL model and Wilson model were used to correlate the solubility data. Among them the empirical equation model showed the best correlation result. At last, the ILs were used to prepare the gel sorbent material for potential use in chemical, environmental or pharmaceutical fields.

Abstract: Si_0.56Cr_0.4M_0.04 (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Rh, and Pd) solvents were investigated to identify new multi-component materials in which carbon is highly soluble, because solubility is a key parameter in solution growth of SiC. The solubility of carbon in Si_0.56Cr_0.4Co_0.04 was 8.37 at%, the highest value among the tested multi-component materials. This is about 2.5 times the solubility of carbon in Si_0.6Cr_0.4. These results show that addition of a small amount of a transition metal enhanced the solubility of carbon in Si_0.6Cr_0.4. This technique for determining carbon solubility is effective for investigating crystal growth using solvents with several components, for which complex thermodynamic calculations are necessary.

Abstract: The aim was to investigate the relation between micromorphology of porosity and electrical resistance of dental luting cements. Five dental luting cements were evaluated: zinc phosphate, glass ionomer, and three types of resin luting cements. Porosity of the specimen was analyzed by micro-CT and electrical resistance of cement was measured at voltage of 125 V up to 30 days and solubility of each specimen was calculated. It showed that the resin luting cements provided the highest electrical resistance regardless of amount of porosity. Zinc phosphate and glass ionomer had high porosity and the lowest resistance (14 and 3 kΩ, respectively). It was found that the electrical resistance of luting cement was not directly affected by the amount of porosity, but it seems to be related to pore connection. There is no correlation between electrical resistance and percentage of porosity but the morphology of porosity may have an influence on the electrical property of luting cement. Models of pore connection were proposed to explain the electrical resistance of luting cement.

Abstract: Pore solution of hardened alkali-activated fly ash paste was extracted by the steel-die method. The aqueous phase composition of pore solution was analyzed using ICP-OES analysis technique. The results show that the concentrations of Si, Al, Ca, K and OH^- decrease with curing time regardless of the curing temperatures (40°C/60°C) and alkaline activators (sodium hydroxide with/without sodium silicate). On the contrary, the concentration of S increases with curing time. A higher temperature curing decreases the solubility of Si, Al, Ca and K in the alkali-activated fly ash, while it doesn’t show much influence on the solubility of S. The plot of the concentration of Al versus the concentration of Si displays a quasi-linear logarithmic relationship. This relationship implies congruent removal of Si and Al from the frameworks of fly ash.

Abstract: We have previously developed a novel chelate-setting β-tricalcium phosphate (β-TCP) cement with non-fragmentation property in vivo. This novel cement has been set on the basis of chelate-setting mechanism of inositol phosphate (IP6). In this study, β-TCP powders were synthesized by mechanochemical method, and the as-prepared powders were heated at 600-1300°C for 1 h. Some properties of the resulting powders were examined. The crystalline phase of the resulting powders in the range of 600-1100°C was of β-TCP single phase. In the cases at 1200°C and 1300°C, the resulting powders were composed of β-TCP and α-TCP. Median particle sizes of the resulting powders increased with heating temperature from 5.35 μm up to 47.7 μm. Dissolution rate of Ca²⁺ ions from the β-TCP powders was measured by Japanese Industrial Standard T 0330-3. When the heating temperature was at 700°C, the Ca²⁺ ions solubility was highest among examined ones. The β-TCP powder heated at 700°C for 1 h will be expected as the starting powder for paste-like artificial bone filler with excellent bioresorbability.

Abstract: The precipitation and dissolution behavior of niobium carbo-nitrides is of particular interest for many technical applications. Niobium-microalloyed high strength low alloy (HSLA) steels are widely used in civil construction, automobile and line pipe applications. These steels rely on thermomechanical processing. In this context, coupled processes like thin slab casting and thermomechanical rolling of microalloyed steel grades require most precise information on the precipitation state at the individual processing steps. Reasonable equations for the solubility product at thermal equilibrium can be taken from literature but kinetics is largely unknown. Conventional X-ray technology is not able to detect small volume fractions below 0.1% of nanoscale precipitates. Investigation of nanoscale niobium precipitates by transmission electron microscopy (TEM) analysis or chemical extraction methods is common practice. However, TEM suffers from statistical relevance and chemical extraction will not give information on particle distribution and orientation. Investigation by high energy synchrotron X-ray of about 100 keV offers statistical relevance as volumes of several cubic millimeters are regarded. This large reflecting sample volume allows to detect nanometer-sized particles and provides very high angular resolution leading to an exact determination of the reflection peaks. The wavelength of around 0.12 Å is able to analyze nanometer-sized particles. Due to the high energy of the applied synchrotron radiation, precipitation and dissolution reactions could be observed during thermal treatment inside a soaking furnace. The results establish this technology for analysis of nanoscale niobium carbo-nitride precipitates