Repository of the Institute for Material Testing (RIMS)
Not a member yet
1132 research outputs found
Sort by
Experimental and Discrete Element Model Investigation of Limestone Aggregate Blending Process in Vertical Static and/or Conveyor Mixer for Application in the Concrete Mixture
Get PDFThe numerical model of the granular flow within an aggregate mixture, conducted in the vertical static and/or the conveyor blender, was explored using the discrete element method (DEM) approach. The blending quality of limestone fine aggregate fractions binary mixture for application in self-compacting concrete was studied. The potential of augmenting the conveyor mixer working efficiency by joining its operation to a Komax-type vertical static mixer, to increase the blending conduct was investigated. In addition the impact of the feed height on the flow field in the cone-shaped conveyor mixer was examined using the DEM simulation. Applying the numerical approach enabled a deeper insight into the quality of blending actions, while the relative standard deviation criteria ranked the uniformity of the mixture. The primary objective of this investigation was to examine the behavior of mixture for two types of blenders and to estimate the combined blending action of these two mixers, to explore the potential to augment the homogeneity of the aggregate fractions binary mixture, i.e., mixing quality, reduce the blending time and to abbreviate the energy-consuming
Assessment of Grain Size and Grain Refinement Efficiency by Calculation of Released Heat Attributed to Formation of Primary Aluminum Crystals During Solidification of Al7Si4Cu Alloy
No full textAssessing heat released only related to the formation of primary crystals provides results with a significantly higher sensitivity than a traditional assessment of undercooling value. In this work, two similar Ti5B1 master alloys (commercial and refined) are used for grain refinement of Al7Si4Cu aluminum alloy to assess narrow differences in heat release during primary crystallization. The heat released related to primary crystallization is 2.50 +/- 0.03, 3.16 +/- 0.12, and 7.92 kJ kg(-1) for samples treated with the refined master alloys, commercial master alloys, and sample solidified without grain refinement, respectively. The acquired results showed that the suggested method is more efficient in comparison with traditional metallographic or undercooling methods for the assessment of grain refining efficiency with the potential to extend the suggested approach on a wide range of metallic structures where solidification occurs by eutectic-type primary crystallization characteristics
Environmental Product Declaration (EPD) for Clay Construction Product
No full textEnvironmental Product Declarations (EPD) for clay construction products provide
important information about those products and their use. The professional and technical
foundations of the EPD must be verifiable and must meet the requirements of ISO 14025 for
ecolabels, the ISO 21930 for EPD for building products, and the more specific EN 15804 for
Product Category Rules (PCR) for construction products EPD. Each EPD needs to cover all
life cycle stages of a product (module A-D). Life Cycle Assessment (LCA) analyzes all phases
of the life cycle of a construction product, takes into account the different impacts of these
phases on the environment, evaluates, analyzes and interprets the results. In this study, LCA
analysis for clay construction products 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). Based on the results, the production phase
(modules A1-A3) contributes the most to the environmental impact. Taken as a whole, most
impact categories are dominated by energy processes and consumption of raw materials
Analysis of Hertz contact stresses for metallic material with carbides
No full textHertz contact and the resulting stress-strain state arising from the contact between two elastic solids have practical application in hardness testing, wear and impact damage of engineering ceramics, the design of dental prostheses, gear teeth, ball and roller bearings and many other engineering applications. Although the common concepts for studying these problems implies that the analysis is perform taking into account that elastic solids are imperfection free, the real problems, as well as various failure analysis, underline significance in taking into account those imperfections, [1]. Imperfections in metallic materials can be non-metallic inclusions, carbides, pores and other microstructural defects, [1, 2]. This paper describes model of two cylinders in contact made by metallic material with carbides. The Finite Element Analysis (FEA) is performed in order to discuss the influence of position, orientation and dimension of carbides on Hertz stresses for two cylinders in contact. Fig.1a shows the FEA model developed for calculation the Hertz stress state for two cylinders, and Fig.2 shows the position and dimension of carbides for two of the series of modelled cases
Dizajn maltera za konzervaciju - Rimska granica na Dunavu 2000 godina kasnije
Get PDFDizajn maltera za konzervaciju – Rimska granica na Dunavu 2000 godina kasnije (Mortar Design for Conservation – Danu be Roman Fron ti er 2000 Years After: MoDeCo2000) je naučnoistraživački projekat u čijem su fokusu istraživanja rimskih maltera koji potiču iz građevina vojnih utvrđenja i naselja na području dunavskog limesa na teritoriji današnje Republike Srbije. Nosilac projekta je Arheološki institut (dr Emilija Nikolić – rukovodilac projekta i dr Mladen Jovičić) a sprovodi ga zajedno sa Tehnološkim fakultetom Univerziteta u Novom Sadu (dr Snežana Vučetić i dr Jonjaua Ranogajec) i Institutom za ispitivanje materijala, Beograd (Ljiljana Miličić i Ivana Delić Nikolić). Projekat traje od 2020. do 2022. godine i finansira se iz programa PROMIS, Fonda za nauku Republike Srbije
Some Aspects of Pile Testing Using Dynamic Load Test (DLT)
Get PDFThe paper presents typical examples of pile load tests with a specific analysis of results, whereby the test methodology relies on existing ASTM standards, own knowledge and experience. The pile tests were conducted using own equipment with licensed hardware and software for the Dynamic Load Test (DLT). The tests have shown the correct and problematic situations that arise when analyzing the bearing capacity of piles. Aspects of application of different equipment and testing methodologies in different situations are indicated. Also, the need to develop a plan for testing the load capacity of piles when it comes to large and significant structures was pointed out
