Repository of the Institute for Material Testing (RIMS)
Not a member yet
1132 research outputs found
Sort by
The recycling of demolition roof tile waste as a resource in the manufacturing of fired bricks: A scale-up to the industry
Get PDFThis study illustrates the utilization of roof tile waste as a resource in the manufacturing of fired bricks. Although commonly referred to as demolition waste, it is technically classifed as construction and demolition waste
(C&D). This demolition waste was used as a partial replacement of two soils (alluvial and laterite soil) at three firing temperatures that were considered economical (700, 850, and 900 ◦C). The waste considered was obtained from roof tiles previously fired at a low temperature below 800 ◦C, thus containing residual carbonates and clay
minerals. The increased waste input resulted in higher firing shrinkage, bulk density, and water absorption while
decreasing loss on ignition. An increase in firing temperature led to higher firing shrinkage, loss on ignition, and
bulk density, but lower water absorption. The bricks met both Indian and ASTM standards for 2nd and 3rd class
by adding 20–35 wt% of roof tile waste and firing at 850–900 ◦C in laboratory and industrial settings. The
minimum acceptable quality for the produced bricks was achieved with an addition of 35 wt% waste, resulting in
a water absorption of approximately 19% and a compressive strength ranging from 6 to 9 MPa. The study suggests that incorporating waste from demolished roof tiles into the production of burned bricks can be advantageous.
It can partially replace the need for soils, reduce natural resource usage, lower energy consumption
during production, and decrease the carbon footprint
Additive technology and 7r methodology in circular economy for wearable sensors production
Get PDFThe paper presents the 7R algorithm of the circular economy principle in realizing wearable sensors. The application of additive manufacturing in the realization of sensors is essential from the point of view of sustainable production, which starts from the material and ends with its recycling process. All seven principles and their connection with additive manufacturing as a critical element in the circular economy are presented. The paper defines the theoretical framework for realizing a sustainable wearable sensor. The production of such sensors primarily refers to the application of flexible 3D printing and electronic components that can be quickly replaced, modified, disassembled, and recycled
Development of conceptual model for environmental monitoring in underground coal mining
No full textDespite the implementation of various technological solutions, underground coal mining has a significant environmental impact. This paper focuses on the impact of underground coal mines on the environment, with particular emphasis on such mining activities in the Republic of Serbia and stresses the importance of monitoring as a phase of environmental protection. The current practice of environmental monitoring in underground coal mines in the Republic of Serbia lacks systematic and comprehensive procedures, making this research paper an original and significant contribution to the mining industry. The primary objective of this research is to investigate the interaction between underground mining operations and the environment, provide a realistic assessment of the environmental impacts, and emphasize the importance of measuring certain parameters. A conceptual model of environmental monitoring, encompassing global trends and research, as well as the existing institutional framework in the Republic of Serbia, has been developed in this paper. Consistent implementation of this model can help establish quality procedures to reduce the impact of underground coal mining on the environment. The research demonstrates that the parameters with the greatest direct impact on the environment are the mine air (i.e. methane), waste rock disposal, ground subsidence, and indirect impacts such as electricity consumption. These influential parameters are analysed using the example of the Soko brown coal mine
Reapplication Potential of Historic Pb–Zn Slag with Regard to Zero Waste Principles
No full textSmelting used to be less efficient; therefore, wastes obtained from historical processing at smelter plants usually contain certain quantities of valuable metals. Upon the extraction of useful metal elements, metallurgical slag can be repurposed as an alternative mineral raw material in the building sector. A case study was conducted, which included an investigation of the physico-chemical, mineralogical, and microstructural properties of Pb–Zn slag found at the historic landfill near the Topilnica Veles smelter in North Macedonia. The slag was sampled using drill holes. The mineralogical and microstructural analysis revealed that Pb–Zn slag is a very complex and inhomogeneous alternative raw material with utilizable levels of metals, specifically Pb (2.3 wt.%), Zn (7.1 wt.%), and Ag (27.5 ppm). Crystalline mineral phases of wurtzite, sphalerite, galena, cerussite, akermanite, wüstite, monticellite, franklinite, and zincite were identified in the analyzed samples. The slag’s matrix consisted of alumino-silicates, amorphous silicates, and mixtures of spinel and silicates. Due to the economic potential of Pb, Zn, and Ag extraction, the first stage of reutilization will be to transform metal concentrates into their collective concentrate, from which the maximum amount of these crucial components can be extracted. This procedure will include combination of gravity concentration and separation techniques. The next step is to assess the Pb–Zn slag’s potential applications in civil engineering, based on its mineralogical and physico-mechanical properties. Alumino-silicates present in Pb–Zn slag, which contain high concentrations of SiO2, Al2O3, CaO, and Fe2O3, are suitable for use in cementitious building composites. The goal of this research is to suggest a solution by which to close the circle of slag’s reutilization in terms of zero waste principles. It is therefore critical to thoroughly investigate the material, the established methods and preparation processes, and the ways of concentrating useful components into commercial products
Properties of concrete with crumb rubber in relation to ordinary and aerated concrete
Get PDFWaste tires have long been a challenge for waste disposal. In an effort to mitigate the impact of solid waste on the environment and recycle it as much as possible, research has been conducted into the possibility of using this waste in concrete mixes. However, the use of these waste materials in concrete is still not popular due to the lack of knowledge of the properties that can be obtained with this material. Hence, the aim is to use waste material in the production of concrete, and that concrete mixes with this material have satisfactory performance. The paper presents the results of research on concrete in which volume replacement of fine aggregate with crumb rubber was performed in the amount of 5%, and this concrete was compared with the control concrete mix and aerated concrete. All concrete are made with a water-cement factor of 0.45. The performance of fresh concrete was monitored for 10, 30 and 60 min. In the case of concrete with the addition of crumb rubber, after 60 min, higher values of air content were obtained, and lower values of volume mass of fresh concrete compared to the initial measurements. The obtained test results of hardened concrete indicate that concrete with crumb rubber has a lower compressive strength compared to the control concrete mix, while compared to aerated concrete, they obtain approximate compressive strength values
Determination of the ductile-to-brittle transition temperature of NIOMOL 490 K steel welded joints
Get PDFThis paper is dedicated to the ductile–brittle transition behaviour of the microalloyed structural steel NIOMOL 490 K. This steel grade is used for welded pressure vessels subjected to dynamic loads and operating at sub-zero temperatures. Therefore, it must have an acceptable toughness. Due to its importance for the safety assessment of pressure vessels, a characterization of this steel was carried out using the Charpy V-notch impact test in the temperature range between - 60 ◦C and + 60 ◦C. The notches were located in parent material, heat affected zone
and weld metal. In this paper, the tensile strength properties at ambient temperature and the nil ductility temperature in the temperature range from - 60 ◦C to + 60 ◦C are presented
Corrosion Damages of Pipelines Assessment by Using the Finite Element Method
Get PDFIn order to ensure pipeline safety during their service life, all relevant construction, testing and safety requirements must be met. Corrosion damage is a major hazard to the steel pipeline as a whole, and it is necessary to comply with inspections and adequate maintenance so that destruction with catastrophic consequences would be avoided. In this paper, the standard calculation for determining the maximum acceptable corrosion damage length according to the RSTRENG method is presented using the calculation of the corrosion-damaged structure of the ammonia (NH3) transfer pipeline. After that, the methodological approach to calculation using the finite element method (FEM) is presented in accordance with the methods defined by the new and general approach to standardization and technical harmonization for pressure equipment (Pressure Equipment Directive). The aim of the work was to present advanced modeling techniques of corroded surfaces based on FEM in order to develop a procedure for evaluating the residual strength of steel pipelines in the chemical industry
Metodologija određivanja plastičnog i elastičnog dela opterećenja čelika kod ispitivanja nisko cikličnim zamorom
Get PDFKORISNIK TEHNIČKOG REŠENJA: Univerzitet u Beogradu, Mašinski fakultet, Laboratorija za dinamička ispitivanj
Neutron shielding parameters of selected types of concrete
No full textIn this scientific research, the definition of appropriate neutron shielding
parameters is presented and the results of calculations or measurements of these
parameters are presented for four selected types of concrete that are used in
protection against neutron radiation. A method for calculating the fast neutron
effective removal cross section is considered, which has its own specificities
because it takes into account different types of interactions of fast neutrons with
the materials from which the selected types of concrete are made. In addition, the
values of macroscopic neutron absorption cross section for thermal neutrons,
macroscopic neutron scattering cross section and total macroscopic neutron
attenuation cross section, which includes scattering of fast neutrons and
absorption of thermal neutrons, are presented for the selected types of concrete.
Based on the analysis of neutron shielding parameters, type of concrete with
coarse-fine aggregate limonite-limonite has a higher level of ability to protect
against neutron radiation compared to concrete with coarse-fine aggregate
magnetite-limonite and concrete with barite-barite.ceo rad na CD
UDK: 539.12/.16:666.97
PETG as an Alternative Material for the Production of Drone Spare Parts
No full textMaterial selection is the main challenge in the drone industry. In this study, hardness,
abrasive wear, impact resistance, tensile strength, and durability (frost resistance and accelerated
ageing) were identified as important characteristics of drone materials. The additive manufacturing
technology was used to produce the drone leg specimens and prototype. The suitability of PETG
as a primary filament material in the design of the drone leg was investigated. Nine series were
printed with different raster lines (0.1, 0.2 and 0.3 mm) and infill densities (30, 60 and 90%). Printed
specimens were annealed in salt and alabaster, as well as immersed in liquid nitrogen. Series with
raster line-infill densities of 0.1–30, 0.3–30, 0.1–90 and 0.3–90 were identified as the most interesting
ones. Thermally treated specimens had better mechanical and durability properties, and infill density
was found to be the most important printing parameter. Specimen annealed in salt with a raster line
of 0.1 mm and infill density of 90% had the best results. Since ABS is the most common material used
for drone leg production, its properties were compared with the PETG specimen, which showed the
best properties. The potential of PETG as an alternative material was proven, while the flexibility,
productivity and suitability of the leg drone design were additionally confirmed