Papers by Keyword: Density

Abstract: The most common residual viscosity correlation used in the petroleum models is JOSSI et al [1] where the residual viscosity is represented by a polynomial function of 4th degree involving the reduced density ρr ([(η-η*)ξ+10^-4]^1/4=Σ⁴₁₌₀(aiρrⁱ)). Based on this formula, it is possible to predict various uncertainties that can be accumulated and thus alter the performance of viscosity restitution which depends on several factors:The quality of the initial adjustment of the coefficients a_i;The precision on the density;The accuracy with which are known the characteristics of the constituents of bases;The validity of the rule of the mixtures selected for the determination of the pseudo-critical coordinates T_cm and P_cm and the equivalent molar mass of the mixture.As far as the results are concerned, we reveal that with the new set of coefficients it is possible to obtain a more preciserepresentation compared to that of JOSSI. The method of JOSSI seems to be especially interesting for the viscosities restitution of systems containing light and close paraffins. However, for some pure substances, the opposite situation could be true. Among the four equations-of-state used, it has been found that the cubic equation-of-stateof PENG and ROBINSON should not be used since we would like to generate the density. Finally, we are not expecting a perfect systematic representation. As demonstrated in our model, if for light alkanes one can expect an average deviation ofless than 10%, for certain pure substances the deviation exceeds 20%.

Abstract: Boron oxide-based systems on structure and properties are similar to silicate systems, but they are more fusible and so are widely used in modelling various metallurgical processes. This paper presents the results of viscosity, electrical conductivity, surface tension and density measurements of the B₂O₃–CaO system with a content of 25–45% CaO in the temperature range above the liquidus temperature. To measure viscosity, vibration viscometry was used. Electrical conductivity was measured via the contact method using an alternating current bridge. Surface tension and density were measured using the lying drop method. The obtained results were used to describe the structure of borate melts.

Abstract: The present work deals with the synthesis and characterization of Al-Cu-SiC-Al₂O₃ hybrid metal matrix composite with varying percentage of Al₂O₃. The synthesized hybrid composite samples were conventionally sintered at two different sintering temperatures i.e. 500°C and 600°C for 1 hr each. SEM investigation predicts the uniform distribution of reinforcing particles. The SEM and XRD results of the sintered composites revealed the presence of a new intermetallic alloy CuAl₂ phase along with Al and SiC phases. It is observed that the density and hardness of Al-Cu-SiC-Al₂O₃ hybrid composite increases with increase in wt % of Al₂O₃ and sintering temperature.

Abstract: At present time complex alloyed brasses are widely used for manufacturing of parts worked in fray conditions. The mechanical and service properties of this alloys are provided by presence of different structural constituents in the structure of alloys. The wear resistance is a basic property of complex alloyed brasses. The information on actual problems in the industrial production of cast bars, semi-finished products and [ pfrts]-непонятно] of complex alloyed brasses is presented in the article. In accordance with the increasing requirements of consumers to reliability and service life of parts the complex alloyed brass Cu62Zn31.6Mn3Al2Si0.8Ni0.4Cr0.2 was proposed as a material for production of parts. The development of technology of melting and semi-continuous casting of complex alloyed brass is an important problem. Moreover, for estimation of thermal contition of ingot and simulation of the process of solidification of the ingot, it is necessary to know thermal physic and physical characteristics of an alloy. Therefore, the research on determination of heat conductivity, heat capacity and density of complex alloyed brass, depending on temperature, was carried out. The obtained experimental data can be used to thermos-technical calculation of thermal contition of ingot and simulation of the process of solidification of ingot during semi-continuous casting for the purpose of determination of technological parameters of casting.

Abstract: The possibility of using aluminosilicate raw materials and ash and slag waste of thermal power plants in the production of ceramic bricks is considered. The physicochemical processes taking place in the preparation of ceramic materials based on ash and slag waste are studied. In order to accelerate the process of sintering a ceramic material, the possibility of using an additive of sodium silicate lump was investigated. Its influence on the technological properties of ceramics of rational composition was studied and the expediency of introducing this additive into the mixture in the amount of 10% was established. The dependences of fire shrinkage on the amount of ash and slag waste at a firing temperature of 1050 ° C are determined.

Abstract: The article deals with the problems of using wastes formed after extraction of copper, nickel, gold, etc. from slags. A review of existing developments in the field of using technogenic products for the production of ceramic building materials with desired properties was carried out. The results of the study of the prospects of using stale slags from non-ferrous metallurgy on the example of the slags from the Mednogorsk Copper-Sulfur Plant of the Orenburg region in combination with fusible clay from the Alimsaysky deposit for the production of ceramic brick are presented. The data of studying the technological properties of raw materials, the development of compositions are given. The effect of the material composition of the clay / slag mixture on the strength, shrinkage, water absorption and density of experimental samples – bricks after calcination in the range of 900– 1200 ° C is determined.

Abstract: The microstructure, physical, dielectric and the piezoelectric characteristics of the (K_0.5Na_0.5) (Nb_0.9Ta_0.1) O₃ (KNNT) ceramics as a function of the sintering temperature and Nd₂O₃ dopant were inspected in this work. It was found that the sintering temperature has a significant impact on the above-mentioned properties. In the same context, the addition of HYPERLINK "https://pubchem.ncbi.nlm.nih.gov/compound/Neodymium_oxide" neodymium oxide led to remarkable improvement in the microstructure, density, dielectric and piezoelectric properties of KNNT ceramics when compared to undoped ceramics.

Abstract: Nowadays various light concrete types have many advantages as compared to heavyweight concrete (total structures mass decrease, increased thermophysical properties, less material consumption). Various industrial wastes use such as fly ashes, slag and bottom ash was suggested to enhance the light concretes effectiveness. This is greatly important for a green light concrete production since it is very important to obtain new types of environmentally friendly materials using wastes. The article substantiates the light concrete use and creation with organo-mineral additives based on industrial waste, analysis of the second-order mathematical model describing the bottom ash (BA) amount effect of Vung Ang TPP and expandable polystyrene spheres (EPS) on the light concrete density and compressive strength at the age of 28 days of normal hardening is done. In this work, the BA and EPS amounts varied from 14.5 to 45.5%, respectively, of the cement weight and from 24.5 to 55.5% of the concrete mix volume. The effect of expanded polystyrene spheres (EPS) and bottom ash (BA) TPP "Vung Ang" amounts as the input parameters on the polystyrene concrete properties (PCP) were investigated in this study. On the one hand, various proportions of BA (14.5, 20, 30, 40 and 45.5%) were blended in concrete mixes as partial weight replacement for Portland cement. On the other hand, EPS amount was replaced by the fresh concrete volume in the range from 24.5% to 55.5%. Additionally, the central composite design method of Box-Wilson for second order factors was used to predict the EPS and BA effects on the polystyrene concrete properties. The results showed that the proposed regression equations of this mathematical model achieved an adequate prediction accuracy. Hence, the effects of both bottom ash contents and expanded polystyrene spheres on the dry density and 28-day compressive strength of the PSC-specimens were significant. In the future, further investigations have to be carried out to study the quality prediction of green light concrete containing various wastes.

Abstract: This paper presents the lime binding forced carbonate-hardening materials properties formation study and determins the stability of these properties during long-term storage and use under normal conditions. The tests showed these materials stability properties over time, confirming the strength and density growth of the test samples after long storage due to the calcium hydroxide recrystallization completion into calcium carbonate processes. Also, the results of the samples carbonate hardening study under natural conditions during 18 months are presented. An efficiency assessment of forced carbonate hardening as one of the methods of recycling technogenic CO₂ in order to reduce its emissions in the atmosphere, and, in the result, to obtain high-quality construction materials has been made.

Abstract: The effect of superplasticizing, foam agents, various fiber aggregates on the physical and mechanical properties of cellular concrete has been studied. The article covers the results of experimental studies conducted to determine the effect of foam agents PO-6 and PB-2000, as well as polymeric and basalt fiber on the pore structure of foam concrete. The dependence between the change in density and strength of cellular concrete and the structure of its pore space has been determined.