Papers by Keyword: Physical Properties

Abstract: Metal hollow mini-spheres (MHMS) present a basis for the creation of new structured materials due to their low weight and energy adsorption capacity. Typically, MHMS are made of steel with a high level porosity in the sphere’s wall 80-110 microns thick. Modification of the outer surface by copper coating of 20-30 microns imposed by vacuum sputtering provides several times higher electrical conductivity, lower porosity of the outer layer and smoother surface, preserving light weight and flotation properties. This modification will provide better possibilities for spheres’ consolidation by means of sintering and electric brazing and creation of new cellular structures.

Abstract: Nd³⁺ doped lithium borotellurite glasses were successfully been prepared by conventional melt-quenching method with the chemical composition (70.0)B₂O₃-(5.0)TeO₂-(25.0-x) Li₂CO₃-xNd₂O₃ (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 2.0 mol%) by varying the Neodymium content. The physical properties such as density, molar volume and oxygen packing density were measured. The structural properties have been studied through X-ray diffraction (XRD) analysis and Fourier Transform Infrared (FTIR) spectroscopy. The XRD pattern has been used to confirm the amorphous nature of the glass samples. There are no sharp peaks were observed in XRD patterns of the glass samples which confirmed the amorphous nature of the glass. FTIR spectra were used to analyse the functional groups present in the glass samples. The FTIR spectra reveal the presence of B-O-B, B-O, BO_3, BO_4,Te-O and characteristic of the hydrogen bond in the prepared glass samples.

Abstract: Five distinguish glass samples were prepared by melt quenching technique of the composition (81-x)H₃BO₃-19BaCO₃-xDy₂O₃ with x = 0, 0.2, 0.4, 0.6 and 0.8 mol%. The effect of Dy³⁺ to the barium borate glass can be investigated in terms of their physical properties such as density, molar volume and oxygen packing density. The structural properties were analyzed by X-Ray Diffraction (XRD) technique and Fourier Transform Infrared Spectroscopy (FTIR). The result revealed that the increment of mol% of Dy³⁺ in the compound generally will increases the density and molar volume of the glass samples. The amorphous nature of the glass system was verified from the XRD spectra pattern. Meanwhile, the FTIR spectra shown the presence of Ba²⁺, BO₃, BO₄, B-O-B linkage, H-O-H and isolated borate in the glass network.

Abstract: An unconventional approach to the design of cement mixtures with the addition of cement bonded particle board (CBPB) production waste is presented, which is characterized by high water consumption. For various compositions of fine-grained concrete prepared in accordance with the simplex-lattice design of the experiment, compressive strength and bending, as well as density of the samples, depending on the mixture factors, were researched. The fractions of CBPB wastes, water and sand at constant cement consumption were chosen as the influencing factors. For practical purposes, related to the design of cement composite compositions with the addition of CBPB wastes and with the determination of optimal values of the selected factors, mathematical models have been constructed on the basis of laboratory experiment data and with their help, the optimal ratios of components in the mixture have been determined. It was found that the content of water for the mixture mixing in the mixture has a significant effect on the strength characteristics of composites: increase of the strength of materials with a decrease in the water-cement ratio is a characteristic for compositions with the minimum amount of CBPB waste; increasing the content of the CBPB waste in the mixture the increase of the water-cement ratio leads to gain in strength. Optimal ratios of the mixture components providing maximum utilization of CBPB waste without loss of strength of composites are given.

Abstract: The experience of using slime wastes in the production of wall ceramic bricks is considered. The results of the investigation of clayey raw materials in the deposits of the Western Orenburg region and technogenic wastes of the fuel-energy and oil-producing complex are analyzed with an analysis of their effect on the properties of wall ceramics: density, strength, and water absorption. Based on the results of the research, optimal compositions were developed using ash and slag wastes in a composition with aluminosilicate clay raw material - loam. The influence of drill cuttings with an increased content of calcium oxide on the composition and physical and mechanical properties of wall ceramics, the effect of a composition of low-grade local clay raw materials and drill cuttings on the formation of the structure and properties of ceramic materials is shown. The analysis of the volumes of formation of ash-and-slag wastes and drill cuttings is given, which makes it possible to introduce technogenic wastes into secondary production and to expand the mineral and raw materials base for the production of ceramic bricks.

Abstract: The present study investigates the influence of carbon fibers of LO-1-12N/40 brand and modified carbon fibers of "Belum" brand on performance properties and structure of polymer composite materials based on UHMWPE of Gur-4150 grade. It has been established that introduction of both modified carbon fibers and LO-1-12N/40 carbon fiber in an amount of from 1 to 10 wt.% into the polymer matrix does not lead to significant changes in stress-strain properties of composites compared to the starting polymer. It is shown that the wear resistance of the obtained materials is significantly increased when filling with 5 wt.% carbon fibers of "Belum" brand. The rate of mass wear of polymer composite materials is reduced by 3.3 times; the friction coefficient of PCM is lowered by 3.5 times relative to the starting polymer.

Abstract: Micro-fillers based on natural mineral wollastonite, modifying fine-grained concrete and improving its physical and mechanical characteristics, are developed and studied. The influence of the most common stabilizers on the aggregate stability of wollastonite-based microdispersed systems in the aquatic dispersion environment is considered. The optimal parameters, ensuring the production of micro-fillers in the form of stable suspensions, are developed. The application efficiency of the wollastonite-based filler due to its micro-reinforcing properties is revealed. These properties are specified by the formation of needle-shaped crystals by the ultrasonic dispersion in the aquatic environment, chemically related to cement-containing raw materials and contributing to the active selective adsorption of the binder hydration products. It has a significant influence on the rheological parameters of cement composites, on structure formation, as well as on their strength and deformation properties.

Abstract: The paper presents the results of the study dealing with improving the physical and mechanical properties of building ceramics samples: mean density, compressive strength, wear resistance, impact resistance, water absorption, thermal conductivity coefficient, and frost resistance. In the study the organic-mineral additive based on industrial wollastonite with the superplasticizer S-3 was used. The most functional amount of the applied additive, as well as the optimal volume of water in the molding mixture and the firing temperature were determined with the method of experiment mathematical planning. In the course of the studies the specifics of the organic-mineral additive influence on the properties and structure of building ceramics are revealed. The findings are attested by electron microscopy data. The application of the organic-mineral additive improves the performance characteristics of building ceramics samples.

Abstract: The physical and mechanical properties of lightweight constructional heat-insulating concrete (sawdust gypsum concrete) with high-strength gypsum binder, modified by food cotton microcrystalline cellulose and organic fillers of plant origin from the waste wood of coniferous and deciduous species in the form of cavitationly processed pine and birch sawdust have been studied. The dependence of the cavitation extraction time of water-soluble reducing substances (sugars) from sawdust on the strength of sawdust gypsum concrete is established. The changes in microstructure of the gypsum matrix, the mean density, bending tension strength and compression strength, the thermal conductivity coefficient of sawdust gypsum concrete on the basis of the cavitationly processed sawdust with the introduction of microcrystalline cellulose are analyzed. It is proven that microcrystalline cellulose compacts the space between the crystalline hydrates of calcium sulfate dihydrate in the gypsum matrix microstructure and improves the physical and mechanical properties of sawdust gypsum concrete.

Abstract: The present paper outlines the results of full-scale tests of climatic stability and the study of resistance to the action of hydrocarbon media of rubbers based on BNKS-18-18 (butadiene-nitrile rubber) and Hydrin T6000 epichlorohydrin rubber containing one of 6PPDstabilizerwith an aromatic amine moiety widely used in synthetic rubbers. Samples are exposed in an open ground under natural conditions of exposure to climatic external factors of Yakutsk in the Republic of Sakha (Yakutia), as well as in the oil environment of Talakanskoye field and I-50A hydraulic fluid in an unheated room. Such indexes of the samples as conditional tensile strength, elongation at rupture, hardness and degree of swelling are measured to determine the resistance of rubbers to aging after the first, third, and sixth months of exposing. The results of the study reveal the contribution of 6PPD stabilizer in maintaining the stability of the physical and mechanical properties of BNKS-18: rubber containing 6PPD has less property changes both in the open air and in hydrocarbon media compared to rubber without a stabilizer. It should be noted that the oil environment is the most aggressive environment, the swelling of rubbers in oil leads to a significant reduction in strength due to a decrease in intermolecular interaction.6PPD stabilizer occurred less effective for the rubber based on Hydrin T6000: changes in properties of the samples containing the stabilizer are larger than those of the samples without the stabilizer. However, unlike BNKS-18-18-based rubber, the swelling of rubber based on Hydrin T6000 led to the greatest stability of the physical and mechanical properties in the oil environment compared to the open air and hydraulic fluids.