Papers by Keyword: Density

Abstract: The study evaluates the method for determination of the rational technical and economic indicators, namely the rational composition and flexural strength, of building materials containing ash-and-slag obtained from heat-and-electric power plant as waste from the combustion of masute and coal. Results of method application were obtained. The study is aimed on reduction of the negative technogenic impact on the lithosphere by developing an appropriate environmental protection technology for utilization of the mentioned above waste as a replacement of sand in building materials made of cement-sand mixture. The rational composition of the building materials containing ash-and-slag waste granules was selected basing on the results of two stages of experimental research – mechanical bending tests of straight two-support beams on a rupture machine. It was proposed to provide a complex index for assessment of the efficiency of ash-and-slag waste disposal in the building materials, which refers to relation of the strength limit to the density of the material per unit value. The results of calculation of the index magnitudes were obtained.

Abstract: The structural, physical and mechanical properties of alumina composites reinforced with various zirconia contents were studied. Zirconia with specific stress-induced toughness mechanisms (from tetragonal to monoclinic) can improve its mechanical properties. The raw materials were commercial products of alumina (Al₂O₃) and zirconia (ZrO₂) with gamma alumina (γ-Al₂O₃) and monoclinic zirconia (m-ZrO₂) phases, respectively. In this study, alumina and zirconia powders containing 0, 10, 20, 30, and 40 wt% were mechanically activated and sintered at 1400°C for 3 h. Fourier transform infrared spectroscopy (FTIR) characterization was used to confirm the functional groups in the sample. Phase analysis of the sintered samples was carried out via X-ray diffraction (XRD). Composite characterization includes diameter shrinkage, density, and Vickers hardness. Corundum (α-Al₂O₃), monoclinic zirconia (m-ZrO₂) and tetragonal zirconia (t-ZrO₂) phases were the observed phases in the sintered sample. The Al₂O₃/ZrO₂ 60:40 sample had the largest shrinkage in pellet diameter, apparent density, and Vickers hardness, at 8%, 4.35 g/cm³, and 1.33 HVN, respectively.

Abstract: The research objective is to simplify the method for estimating the density of straight-run hydrotreated winter diesel fuel (HTDFWs). The density of straight-run hydrotreated winter diesel fuel is one of the quality indicators ultimately determining the density of winter diesel fuel and therefore, the quality of winter diesel fuel in terms of density. Problems: to describe the current methodology for estimating the HTDFWs’ density, isolate the cycles, and express the cycles by formulas. Research methods – analysis, synthesis, comparison, mathematical analysis. As a result, simplified density calculation with expressing cycles by formulas has been proposed. A mathematical model has been obtained to estimate the density of straight-run hydrotreated winter diesel fuel.

Abstract: Cellular concrete (known as foamed concrete) is a lightweight building material with low densities ranging from 900 kg/m³ to 1900 kg/m³, which can have potential applications in civil engineering practices. However, it is very weak in withstanding tensile loads which leads to cracks during shrinkage in the drying stage. Therefore, six different groups of cellular concrete are prepared for a possible application in grouting underneath the foundations to achieve a minimum compressive strength of 2000 psi (13.79 MPa) as per ASTM C476, and for soil nail grout with a minimum compressive strength of 3000 psi (20.86 MPa) as per ASTM C109 at 28 days. Furthermore, these mixtures are undergoing laboratory testing for pushout (using steel cylinders with varied diamters and thickneses) and pullout tests as the subsequent part of this project. All groups contain 0.34 water-to-cement ratio, same size and amounts of sands and superplasticizer (SP). The first group included four control mixes without bentonite and polypropylene fiber (PPF) additives with varied foam content (C1-F1,F2,F3,F4). The remaining groups consist of 17 different mixes blended with either one or both additives. The content effect of foam agent, bentonite clay, and PPF as additives on the density and compressive and flexural strengths of cellular concrete are investigated in this study. The results revealed that the introduction of bentonite and/or PPF in cellular concrete mixtures increased the density and strength. The results revealed that low dry densities (less than 1900 kg/m³) of blended cellular concrete mixtures can reach high compressive strength of 24.37 MPa with 4.74 MPa flexural strength that make them feasible for geotechnical and structural engineering applications.

Abstract: As_xSe_1-x glasses with x from 0,05 to 0,55 were prepared at two melting temperatures, 700 and 850 °C. Batch materials from several suppliers were used for glass synthesis. Density and IR transmittance of glasses were measured. It was found that data for density of glasses prepared at 700 °C have sufficient scatter, so dependence of molar volume on composition is not smooth. Data for glasses synthesized at 850 °C are in good agreement with reference ones. According to data of IR spectroscopy the main impurity in glasses is oxygen in several molecular forms. Oxygen gets in glass together with arsenic. Its content can be noticeably decreased by the heat treatment of As at from 300 to 350 °C and Se at 310 °C before weighting and by the heat treatment of batch at 200 °C before the sealing of silica ampoule. Optical quality of glass samples is good enough for the use them as IR transparent material for lens manufacturing.

Abstract: In this study, PMS gasoline gotten from randomly selected commercial fuel stations was blended with ethanol gotten from agricultural waste and developed nanoparticles Additives (D-NA). The blended samples were analyzed for their physical properties using methods recommended by the American Society for Testing and Materials (ASTM). The tests were carried out on the fuel's density, oxygenates, benzene content, research octane number (RON) and sulphur content. The results shown in the physical property tests done on these blended fuels when compared with the neat gasoline gotten from the Nigerian National Petroleum Corporation (NNPC), industry standards (DPR/SON) and global markets (United States US & United Kingdom UK) shows that the blended fuels meet all required standards and specifications. The additives had little effect on the fuel’s density but showed a sharp drop in its benzene content levels which makes it a healthier choice of fuel. Ethanol blended fuel had a higher oxygenate level than neat gasoline and the D-NA blended fuel. The research octane number for the three fuel samples showed favorably high numbers that fit the standards of the global market. The most interesting result is the Sulphur content which showed an increase in its values for the blended fuels although the values are within industrial and global limits. Keywords: PMS Fuel; physical properties; density; oxygenates; nanoadditives; ethanol

Abstract: This study aims to determine the effect of the mold casting duct variations on shrinkage, porosity defects, density, hardness, and chemical composition of materials. The primary raw material uses melting secondary aluminium through a small-scale smelting furnace. Research study about three kinds of ducts: triangular duct, rectangular duct, and circular duct. The testing chemical composition uses an emission spectrometer. Research founds defects by comparing the dimensions of the original object with the specimen results of each duct variation. The density value calculates porosity defects. ASTM E10 standard Brinell test measures the hardness. Besides, ASTM E3 standard test quantifies the microstructure of the product. The highest average shrinkage is the triangular ducts at 3.68%. The least significant numbers of porosity were in rectangular ducts of 2.964 gr/ml. Higher the density value, the denser the material, and the more negligible the porosity. The density of the material affects the hardness material obtained from the results of the Brinell test. The hardness of the Brinell test brought that the rectangular duct with 102.5 BHN was the most enormous. In addition, the results showed that the chemical composition mainly contained mostly chemical elements (Al) 87.1% as the main chemical ingredient and (Si) 9.51%.

Abstract: Nowadays, there is an ever-increasing demand for lightweight, robust, and low-cost materials. The desire for increasingly exotic and superior materials has become unavoidable as science progresses. The manufacturing industry is looking for more complex geometries. For example, composite materials are a sort of innovative material that blends the properties of its constituent materials. One of the most extensively used composite materials is metal matrix composites. Aluminium matrix composites are lightweight, high-performance structural and functional materials used in a variety of industries, including defense, aerospace, automotive, heating systems, and sports and entertainment. It is really good for the environment to use by-products from agricultural sectors, such as rice husk, as reinforcement with MMCs. The purpose of this research is to use powder metallurgy technology to build an aluminum-based composite with rice husk ash (RHA) and evaluate how its properties may be enhanced. Whereas metal casting can be used to fabricate composites, powder metallurgy is more cost-effective because it allows for the production of parts that are closer to net shape, and castings cool slowly from the liquid state, causing workability concerns as well as other restrictions such as segregation limitations. Good microstructure in the finished product is possible to obtain as powder particles are small and homogenous, resulting in improved mechanical properties. The experiment was conducted using an L27 orthogonal array with four different input parameters from prior studies: composition (wt.% of RHA), compaction pressure (CP), sintering temperatures (STE), and sintering time (ST). On the aluminium based composite, several mechanical tests, such as density and hardness, as well as tribological testing, such as the wear test, were conducted, with each test yielding noteworthy results. To satisfy the industry's needs, a comparison study was conducted.

Abstract: The construction industry relies heavily on concrete for its operations in the development of houses and other infrastructural facilities due to its structural stability and strength. To fulfil the requirement of concrete materials, this study focuses on investigating the use of marble powder as admixture in concrete production and its effect on the fresh and hardened properties of concrete. About 72 samples of concrete were prepared using marble powder admixture in four separate mixes by adding marble dust with the range from 0% to 6% at an incremental rate of 2wt.% of cement. The workability of the concrete mix with marble waste admixture was found to be higher than that of the control mix. The maximum compressive strength increases with the 4% marble powder admixture after 28 days and it equal to 24.50%, as compared with control mix and the flexural strength also shows a maximum increment in strength with 4% of marble powder after 28 days, which is 5.59% as compared with control mix. The density of concrete increases from 2.14 to 2.82 gm. /cm³ with the increase in admixture from 0% to 4%, on other hand with 6% marble waste the density slightly decreases when compared with the result obtained from 4% marble waste admixture. Therefore, using marble powder as an admixture up to 4% in concrete production gives excellent results in compressive strength, flexural strength, and density compared to the control mixes of concrete.

Abstract: Bismuth glasses have been prepared from a commercial-grade chemical glass mixture doped with potassium chromate in different contents. They have been melted at 1250 °C for 4 h, quenched in a metal plate, and annealed at 500 °C for 20 min. The surface morphology of glass samples has been examined using scanning electron microscopy (SEM). The dielectric properties have been investigated. UV-Vis-NIR absorption has been analyzed. The results show the growth of microcrystal precipitated in the glass matrix, and colors of glass change from colorless to green and opaque with the increasing content of potassium chromate. The density of glass decreases with the increasing content of potassium chromate. The UV-Vis spectra show strong absorption of UV. The chromium-doped glasses not only absorb the UV but also the violet and/or blue lights which depend on the chromium contents.