Thermodynamic Modeling of MgO-Al_(2)O_(3)-TiO_(2) System

This scientific paper gives consideration to the information on the structure of the triple component system,in particular MgO-Al_(2)O_(3)-TiO_(2) that serves as a basis for the production of thermal resistance materials.The structure of such binary systems as MgO-Al_(2)O_(3),Al_(2)O_(3)-TiO_(2),MgO-TiO_(2) was described and the data available for the MgO-Al_(2)O_(3)-TiO_(2) system were given.Thermodynamic data on all the system compounds were also presented and used for the computation of a change in the free Gibbs energy in the temperature range form 800 K to 1900 K for the basic exchange reactions.It was established that the triangulation of the MgO-Al_(2)O_(3)-TiO_(2) system was changed in the three temperature intervals:in the temperature range lower than 1537 K TiO_(2) existed as the polymorphous modification,i.e.anatase;in the temperature range from 1537 K to 2076 K TiO_(2) existed as a polymorphous modification in form of rutile and tialite was stable;and at the temperatures above 2076 K the availability of stochiometric compound of Al4TiO_(8) was possible.In the temperature range lower than 1537 K the two-phase equilibra of Al_(2)O_(3)-MgTi2O_(5),Mg-MgALCU MgTiO_(3)-MgAl_(2)O_(4),and Mg_(2)TiO_(4)-MgAl_(2)O_(4) were stable;in the temperature range from 1537 K to 2076 K the two-phase equilibria of MgTigO_(5)-AlgTiO_(5),MgTiO_(3)-Al_(2)TiO_(5),MgTiO_(3)-Al_(2)O_(3),MgTiO_(3)-MgAl_(2)O_(4),and Mg_(2)TiO_(4)-MgAl_(2)O_(4) were stable,and above 2076 K the MgTi_(2)O_(5)-Al_(2)TiO_(5),MgTi_(2)O_(5)-Al_(4)TiO_(8),Al_(4)TiO_(8)-MgTiO_(3),Al_(4)TiO_(8)-Mg_(2)TiO_(4),Al_(4)TiO_(8)-Mg0,and Al_(4)TiO_(8)-MgAl_(2)O_(4) systems were stable.

Prediction of the Melting Paths of Wollastonite-Containing Compositions

The article analyzed the main groups of thermal insulation(TIM)and slag-forming(SFM)mixtures produced by leading foreign companies:acidic ones based on the SiO2–Al2O3 system,basic ones based on the CaO–MgO–Al2O3 system and medium basic ones based on the CaO(MgO)system–Al2O3–SiO2.It is shown that achieving the necessary properties of the SFM and TIM requires strict observance of the mass content of the components of mixtures produced on the basis of synthetic materials in granular form with a given dispersion.Compliance with a given composition and dispersion is associated with the need to provide a given melting temperature(for intermediate ladles 1250–1450℃,for molds 950–1150℃),neutrality to the cast metal,protection of the melt from secondary oxidation,minimization of heat loss from the melt mirror,absorption of non-metallic inclusions of various natures(Al2O3,CaO,SiO2,TiO2,less often MgO-containing)and sizes;as well as a number of specific requirements:compatibility with the working layer of the lining of the bucket,maintaining the work of the stoppers,minimizing harmful gaseous emissions,etc.It is known that Al2O3,TixOy,and CaO refractory inclusions in steel cause the majority of defects on the surface of a cold-rolled sheet,therefore,the aim of the work was to analyze the physicochemical regularities and melting paths of the wollastonite-containing compositions during the assimilation of nonmetallic inclusions by them.To analyze the melting paths of the wollastonite-containing compositions in the CaO–Al2O3–SiO2 system,a diagram of the primary crystallization field of anorthite and the adjacent boundary curves is shown,indicating the directions of temperature drop and designating invariant points.The presented scheme adequately reflects the topological regularities of the state diagram of the CaO–Al2O3–SiO2 system.To analyze the melting paths of the wollastonite-containing SFM compositions during the assimilation of TiOx impurities from steel melts,a diagram of the primary crystallization field of CaTiSiO5 sphene with adjacent boundary curves,the direction of temperature drop,and the designation of invariant points is presented.It is shown that steric and kinetic factors have a predominant effect on the formation of the three-layer layer in the SFM(molten,partially molten and unmelted layers).The more uniform the thickness of the entire SFM layer(when it is heated from the melt mirror),the smaller the influence,and the competing processes of solid-phase interaction will start,which provide a gradual accumulation of more refractory compounds and increase the melting temperature of the SFM.

Balanced scorecard-based analysis of customer expectations for cosmetology services:a hybrid decision modeling approach

The goal of this study is to analyze and characterize customer expectations in the cosmetics sector.Within this framework,first,the extant literature is reviewed,and 12 most prominent performance measurement criteria are identified.Then,these criteria are organized along the four different balanced scorecard dimensions.By employing an Interval Type-2 Fuzzy DEMATEL methodology,the weighted importance of these dimensions and criteria are identified.Additionally,with the Interval Type-2 Fuzzy TOPSIS approach,13 leading cosmetic service providers in Ukraine are ranked based on their relative scores.The findings of the study indicate that consumer is the most significant dimension while learning and growth seem to have the least importance.Similarly,it is also concluded that all consumerfocused criteria(i.e.diversification of services,feedback on the product and services,and customer loyalty)have the highest priorities in the complete criterion set.