Repository of the Institute for Material Testing (RIMS)
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Characterization of fracture behavior of a low carbon microalloyed steel for elevated temperature application
Get PDFThe idea of this research was to collect data on the effect of operating temperature on the
impact toughness properties of low-carbon microalloyed steel intended for elevated
temperatures application. The aim of this investigation was to determine the effects of
temperature as well as the effects of specimen orientation with regards to the rolling
direction, on the impact toughness and the relation between its components. Charpy
specimens were made from virgin material and were tested at room and operating
temperature of 540 . Specimens were cut from the pipe in two directions, along the rollind
direction (L-) and transverse to the rolling direction (T-). The tests were performed on an
instrumented Sharpy pendulum 150/300 J, results show the total impact energy values, Etot,
crack initiation energy, Ei, and crack propagation energy, Ep. The macroscopic and microscopic specimens fracture surfaces are shown. Obtainted results of impact tests energy
values, correspond to the SEM micrographs of fractured surfaces
Ugljena prašina u energetski efikasnijoj proizvodnji opeke-od laboratorijskih do industrijskih proba
Get PDFOdređivanja karakterističnih stabilizovanih histereza matematičkom zavisnošću podataka opterećenja kod LCF ispitivanja čelika
Get PDFNumerical simulation of 14Mov6-3 steel CT-specimen Fracture Behavior
Get PDFSteel grade 14MoV6 3 is used for manufacturing of boilers and steam pipelines designed for steam temperatures up to 560°C. This paper presents the numerical simulation of a CT-specimen, using the finite element method. The analysis was performed using Ansys Workbench R21, and represents the initial stage of extensive research involving the behaviour of 14MoV6 3 steel. The goal was to simulate the real experimental conditions, including boundary conditions and loads, which were defined in accordance with relevant standards, and to obtain representative results. The temperature dependent mechanical properties needed for the simulation of plastic behaviour of such specimens under tensile loads were obtained from the experimental data and the literature
Life Cycle Assessment (LCA) for clay masonry units-case study: environmental product declaration (EPD) for clay blocks-production plant of clay blocks in Republic of Serbia
No full textLife Cycle Assessment (LCA) analyses all phases of the life cycle of a construction
product, takes into account the different impacts of these phases on the environment, evaluates,
analyses and interprets the results. In life cycle assessment, the Environmental Product Declaration
(EPD) is a standardized way of quantifying the impact of a product or system on the environment.
This study evaluates the environmental impact of 1 tone of clay blocks produced in production plant
in Republic of Serbia and grouped by use of Product Category Rules (PCR). The aim of this study
is to determine the life cycle stages of the clay blocks that affect significantly to environment. LCA
analysis for clay blocks has been conducted with the One Click LCA software, developed by One
Click LCA Ltd, Finland. All processes have been modelled based on the inventory data given in the
£coinvent database (v3. 6). Based on the LCIA results in this study, product stage (modules A J-A3)
contributes the most to the environmental impact. Taken as a whole, energy processes and raw
material consumption dominate most impact categories
Effect of temperature and specimen orientation on Charpy impact toughness
No full textSteel grade 14MoV6 3 is used for manufacturing of boilers and steam pipelines
designed for steam temperatures up to 540°C. This paper presents the experimental analysis
which included impact toughness test. The analysis resulted in impact energy values, and their
respective components, crack initiation and crack propagation energy, and represents the initial
stage of extensive research involving the behavior of 14MoV6 3 steel. The goal was to
determine the effects of temperature (room vs. elevated), as well as the effects of specimen
orientation with regards to the rolling direction, on the impact toughness and the relation
between its components
Influence of coal ashes on fired clay brick quality using random forest method
No full textCoal ashes have been extensively explored to be used in bricks. Some studies report the improvement of the quality while others claim the opposite. It is still unknown what are the factors that most affect the quality of the products. The database gathered 302 cases obtained from the literature containing the chemical composition of brick clays and the ashes and other relevant parameters like peak firing temperature and soaking time, to understand the quality of the fired bricks. The behavior of developed products is followed through bulk density, open porosity, water absorption, and compressive strength. The overall conclusions were that the compressive strengths were the highest after firing in tunnel kilns, and that class F ashes are highly suitable to be used in the brick industry as a replacement material for brick clay. The random forest method was employed and showed that the highest influence to the quality of coal-clay products was owed to the contents of Fe2O3 and K2O coming from brick clays, and Na2O, Fe2O3, and K2O from the ashes. The comparison of different mathematical models was done, such as the support vector machine, random forest, boosted trees, and artificial neural network
Quadruple-cation wide bandgap perovskite solar cells with enhanced thermal stability
No full textMetal halide perovskites have proven to be excellent semiconductors, with tuneable band gap, high absorption
coefficients and large charge diffusion length. Multi-component lead halide perovskite compositions are widely
studied in order to stabilize the perovskite phase, in particular for wide bandgap formulations. The vacuumdeposition
of multi-component perovskites is not straightforward, as the number of precursors is in principle
limited by the number of thermal sources available in the vacuum chamber. Here we present a process which
allows to increase the complexity of the formulation of vacuum-deposited lead halide perovskites films by
multi-source deposition and pre-mixing both inorganic and organic components. We apply it to the preparation
of wide bandgap CsMAFA triple-cation perovskite solar cells, which are found to be efficient but not thermally
stable. With the aim of stabilizing the perovskite phase, we add guanidinium (GA+) to the material formulation,
and obtained CsMAFAGA quadruple-cation perovskite films with improved thermal stability, as observed by
X-ray diffraction and rationalized by microstructural analysis. The corresponding solar cells showed similar
performance with a remarkable thermal stability, when compared to the triple-cation perovskite devices. This
work paves the way towards the vacuum-processing of complex perovskite formulations, with important
implications not only for photovoltaics but also for other fields of application
Put do prve srpske tehničke ocene za portland-kompozitni cement sa smanjenim sadržajem klinkera
No full textEffects of Maintaining a Building Constructed in the IMS System (Žeželj) with an Approximate Analysis of Hydrodynamical Shock and the Analogy with Lateral Soil Expansion with Cavern Effects During Liquefaction
Get PDFThe paper indicates the problems of maintaining buildings constructed in the IMS system, founded on piles with a basement floor. Also presented are the problems with the installations of buildings with a roof terrace, such as downpipe verticals that are extending through the building, or installations of water supply and sewerage that run through the technical floor at ground level. An approximate analysis of the hydrodynamic impact is presented. The analogy of the effects of caverns in sandy soil with lateral soil expansion during liquefaction was also used. Given the change in climatic conditions, it is necessary in some cases to analyze the influence of atmospheric conditions in the soil-structure interaction. The advantage of buildings built in the frame IMS system (Žeželj) in seismically active areas was also indicated. These buildings are also more resistant to problems that may arise later in construction of deep foundations