Repository of the Institute for Material Testing (RIMS)
Not a member yet
1132 research outputs found
Sort by
Geometric optimization of shaft transition zone based on stress-strain analysis of nature inspired design
Get PDFThe presented research primarily considers with the geometric solutions that Nature has optimized. In the study presented in this paper, the nature inspired transition shapes are used in the research of innovative design and geometric optimization of transition zones of the high-loaded shafts
Potential pathway for recycling of the paper mill sludge compost for brick making
No full textThis study's focus was to develop a potential pathway for recycling of the paper mill sludge compost (PMSC) in brick making. Composting reduces the paper mill sludge (PMS) moisture content considerably and shredding becomes easier. The addition of PMSC leads to an increase of porosities in bricks and makes them lighter, besides delivering energy to the firing process from burning organics. Lighter construction materials help minimize construction outlay by reducing labour and transportation costs and lesser expense on foundation construction. The variability in the experimental data and the brick properties were investigated for two types of soils, typical in the brick industry of India (alluvial and laterite soil), blended with PMSC in five mix ratios (0%, 5%, 10%, 15% and 20%). The samples of oven-dried bricks were fired at two different temperatures (850 and 900 degrees C) in an electrically operated muffle furnace representing typical conditions of a brick kiln. Various properties of bricks were analyzed which included linear shrinkage, bulk density, water absorption and compressive strength. Conclusions were drawn based on these properties. It was found that the addition of PMSC to the alluvial and laterite soil by up to 10% weight yield mechanical properties of fired bricks compliant with the relevant Indian and ASTM codes. Toxicity characteristic leaching procedure (TCLP) tests showed that PMSC incorporated fired bricks are safe to use in regular applications as non-load-bearing and infill walls. This study is timely in light of the European Green Deal putting focus on circular economy. Besides, it fulfills the objective of UN sustainable development goals (SDG)
Application of fly ash to reduce soil dispersivity in embankments
No full textDue to rapid development of modern highways and railroad in Serbia, the need for embankment materials has increased. Deposits of natural materials used for this purpose often contain dispersive soils. On the other hand, thermal power plants in Serbia annually generate several million tons of fly ash, which could be used to reduce the dispersion of material embedded in embankments. The paper presents the results of tests conducted for the first time in Serbia to assess the improvement in natural soil dispersivity with fly ash from a thermal power plant. The dispersivity of mixtures of fly ash and natural soil was tested according to ASTM and BS standards. To determine the optimal ash content, 10, 30 or 50% of fly ash was added to the soil samples. The results show that 30-50% of fly ash reduces the dispersivity of natural soil for one to two dispersion classes
Determination of the Coffin-Manson equation under low-cycle fatigue conditions
Get PDFThe cycle loading of a material results in the modification of its properties and so in this paper is presented the behaviour of the fatigue life using low-cycle fatigue parameters. By applying the Coffin-Manson equation in fatigue loading of the tested specimens, the crack initiation has been computed. The stabilized hysteresis loop is a characteristic of all hystereses and it is used to determine all of the parameters for the low cycle fatigue (LCF) assessment. The experimental results have given us important information on the understanding of fatigue behaviour of high strength low-alloyed steel (HSLA) and its welded joints
Geochemical characterization of sediments from the archaeological site Vinca - Belo Brdo, Serbia
No full textIn this study, a multidisciplinary approach was used for a detailed characterization of sediments from the archaeological site Vina. - Belo Brdo, Serbia, one of the most important Neolithic settlements in Europe. This research aimed to determine the paleoenvironmental conditions during Pleistocene and Early Holocene sedimentation prior to Early Neolithic settlement (similar to 5800 cal BC) and provide novel insight into the interaction between humans and the environment during the Middle and Late Neolithic (5300-4550 cal BC). For the first time, organic geochemical characterization, combined with organic petrography, grain size, mineralogy, and inorganic analysis were done on sediment samples from geological and archaeological sections of the Vina. - Belo Brdo site. In the archaeological section, the layer with remains of the burned house and the overlaying leveling layer were particularly interesting. The samples from the oldest geological layers were characterized by the relatively high content of carbonates, the largest amount of soluble organic matter (OM), predominance of liptinite macerals, along with the prevalence of short and mid-chain n-alkanes indicating a marsh-lake depositional environment. The sedimentation of overlaying geological layers continued in an oxbow lake, followed by a shallow depositional environment with stronger input of vascular plants. This was indicated by an increase of the terrigenous component, a high amount of huminite maceral, especially textinite, the predominance of odd long-chain n-alkanes, as well as the presence of diterpanes, pimarane, and 16 alpha(H)-phyllocladane. Quartz was the most abundant mineral in paleosol, while the OM had a mixed origin with a major input of microorganism in the precursor biomass. Estimated average paleosol temperature around 12-16 degrees C and mean annual precipitation of 938 mm/yr were favorable for ancient civilization settlement. In archaeological samples, the OM was predominantly formed by microorganisms, with a certain contribution of terrestrial plants. Their occurrence was substantiated by the presence of telohuminite, detrohuminite, resinite, and sporinite. The prevalence of n-alkane C-18, along with the occurrence of inertinite macerals, semifusinite and fusinite, in the layer with the burned house remains confirmed the incomplete combustion of woody biomass at temperatures lt 500 degrees C. Organic and inorganic geochemical parameters for the leveling layer covering the destroyed buildings showed analogous composition as the lowest geological layers. This proved that Vina inhabitants excavated material for leveling at a site in their vicinity, and used it for covering the burnt debris, clearing the areas for a new settlement. In this context, the decades long archaeological dilemma of the origin of the leveling material was resolved
Environmental Product Declaration (EPD) For Clay Roof Tiles-Case Study: Production Plant of Clay Roof Tiles in Republic of Serbia
Get PDFEnvironmental 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 roof tiles, produced in production plant in Serbia, defined and grouped by use of Product Category Rules (PCR). The purpose of this study is to determine: (1) life cycle stages of the product which have the major impact on the environment expressed as environmental impact categories; (2) the processes of clay roof tile production which have the most important effects on the environment also expressed as environmental impact categories. The LCA analysis has been conducted with the One Click LCA software, developed by Bionova Ltd, Finland. All processes have been modelled based on the inventory data given in the Ecoinvent database (v3.6). According to the results in this study and observed from the aspect of the product life cycle, the production process has the major impact on the environment, and from the aspect of the resources used, the major impact on the environment has the consumption of energy and the use of raw materials
Ground Robotic Systems for the Inspection of Concrete Bridges
No full textThis paper focuses on reviewing relevant work on autonomous ground systems for concrete bridge inspection. The current inspection of bridges is still based on visual inspection by inspectors or by using semi-destructive techniques. Current inspection practices require a large amount of time for inspection. In addition, complex scaffolding or expensive equipment is required for inaccessible areas, which also poses a risk to the safety of inspectors. These drawbacks could be overcome by using robotic systems equipped with non-destructive techniques (NDT). This paper presents the ground robotic systems that have been used in the inspection of concrete bridges, mainly for the localization of reinforcement, corrosion assessment and crack detection
Autonomni sistemi za pregled mostova
No full textTehnološki napredak i automatizacija prisutni u 21. veku dovode do značajnih promena u većini sistema upravljanja. U sistemu upravljanja mostovima, vizuelna inspekcija je i dalje najzastupljeniji metod za pregled, a rezultati ispitivanja na ovaj način u velikoj meri zavise od stručnosti inspektora. Takav tradicionalni pristup u oceni stanja konstrukcija može biti zamenjen primenom autonomnih sistema koji bi pregled konstrukcija učinili efikasnijim i pouzdanijim. Projekat ASAP, čiji je voditelj Građevinski fakultet Sveučilišta u Zagrebu, usmeren je ka razvoju autonomnog sistema za pregled prometne infrastrukture zasnovanog na robotu penjaču i bespilotnoj letelici. U ovom radu predstavljen je pregled autonomnih sistema koji se do sada upotrebljavali za pregled mostova
High strength low-alloy steels impact toughness assessment at different test temperatures
Get PDFIn many production processes, as well as in the exploitation of machine components and structures, materials are exposed to
impact loads. In structures made of welded joints of high strength low-alloy steels with their constituents (parent metal, weld
metal and heat-affected-zone), the toughness test determines the tendency of steel to brittle fracture, respectively the tendency
to increase brittleness during exploitation.
The strain rate is high and the material manifests much more brittle behavior than is shown by tensile testing. Toughness as
a mechanical property is an important factor that is defined as the energy that needs to be spent in order to achieve fracture.
Parameters obtained by testing the properties of plasticity are the basis for the design of structures in order to achieve
strengths under applied load.
The test results of high strength low-alloy steel toughness assessment at different test temperatures show that temperature
significantly affects the impact toughness of steels and their alloys. At higher temperatures the impact energy on fracture is
high (the material shows the properties of plasticity) while at lower temperatures the impact energy is small (the material is
brittle)
Unapređenje tehnologije aluminotermijskog zavarivanja železničkih šina različitog poprečnog preseka
Get PDFU radu je prikazana nova tehnologija aluminotermijskog zavarivanja (AT) prelaznih šina 49E1 na
60E1(EN 13674-1:2005.), oslonjena na potpuno nove materijale. Ona se odnosi na pešćane kalupe kod
kojih su oblik i dimenzije ulivnog sistema projektovani tako da mogu odgovoriti svim zahtevima za
postizanje zavarenih spojeva zadatog kvaliteta. Da bi ovaj zahtev bio u potpunosti ispunjen,
projektovana je, takođe, AT smeša, čijom se aktivacijom dobija termitni čelik za ispunu, sa temperaturom
izlivanja koja obezbeđuje optimalnu livkost metala, kao i viskoznost troske. U radu su zatim prikazani
rezultati ispitivanja probnih prelaznih zavarenih spojeva, shodno standardima JŽS.Z2.610 i EN 14730-
1:2012, a odnose se na utvrđivanje mehaničkih svojstava zavarenih spojeva, makrostruktirnih i
mikrostrukturnih karakteristika, homogenosti i hemijskog sastava termitnog čelika za ispunu. Dobijeni
rezultati pokazuju da je primenjena tehnologija optimalna, jer obezbeđuje upotrebu ove tehnologije u
industrijskim uslovima na železnici