Brno University of Technology

About: Brno University of Technology is a education organization based out in Brno, Czechia. It is known for research contribution in the topics: Computer science & Fracture mechanics. The organization has 6339 authors who have published 15226 publications receiving 194088 citations. The organization is also known as: Vysoké učení technické v Brně & BUT.

Blended cements consisting of Portland cement–slag–silica fume–metakaolin system

Abstract: In the present study, hydration of four-compound systems consisting of Portland cement and three supplementary cementitious materials : silica fume, blast-furnace slag, and metakaolin, has been investigated by means of isothermal calorimetry and thermal analysis. Substitution of Portland cement was achieved at 25, 30, and 35 mass% by cementitious supplementary materials. Owing to the high specific surface, the silica fume eventuated in more distinctive demonstration of pozzolanic reactions. It decreased C/S ratio and led to the formation of hydration phases with C/S ≅ 1, which is demonstrated by wollastonite crystallization at higher temperatures. Enhanced formation of gehlenite hydrate was proved by DTG when blended cements included higher content of metakaolin and blast-furnace slag. Pozzolanic materials increased the compressive strength of particular blended samples and thus overcame the dilution effect especially at long term of curing. Presented quaternary blended samples in comparison with ordinary Portland cement thus allowed the formation of more thermal stable hydration products and can be considered as promising materials for the development of special concrete also for hydrothermal applications.

A new numerical method of total solar eclipse photography processing

Abstract: A new numerical method of image processing suitable for visual- ization of corona images taken during total solar eclipses is presented This method allows us to study both small- and large-scale coronal structures that remain invisible on original images because of their very high dynamic range of the coronal brightness The method is based on the use of adaptive filters inspired by human vision and the sensitivity of resulting images is thus very close to that of the human eye during an eclipse A high precision alignment method for white-light corona images is also discussed The proposed method highly improves a widely used unsharp masking method employing a radially blurred mask The results of these numerical image processing techniques are illustrated by a series of images taken during eclipses of the last decade The method minimizes the risk of processing artifacts

Experiences With Using of Loading Tests and the “design Assisted by Testing” Method for the Determination and Verification of Structural Members and Details

Abstract: This paper describes experiences with use of different types of experiments (i.e. loading tests) as well as with use of socalled “Design assisted by testing” method given in the standard “Eurocode 1”. Both these mentioned ways are useful in case of a determination and verification of important design parameters, material properties and load-carrying capacities (in case of different types of stresses, used materials or geometric configurations of designed constructions or their elements and details). In this area, during recent years, large number of miscellaneous loading tests have been performed at the authors’ workplace. Therefore, all presented information and all described experiment results in this article are directly based on solved experimental (and theoretical) research programs carried out at Institute of Metal and Timber Structures at the Faculty of Civil Engineering at Brno University of Technology in cooperation with research institutes and companies in the Czech Republic. Most of all research projects were focused on the load-carrying capacity determination as well as on the knowledge about an actual behaviour and failure mechanisms of steel and steel-concrete structural members and details (recently of members made of FRP or GFRP composite, too), usually in case of verification of either existing or newly designed building or bridge structures. Keywords—Design assisted by testing, design characteristics, experiments, load-carrying capacity determination, loading tests, steel constructions, parameters verification.

Experimental analysis of irregularities of metallic surfaces generated by abrasive waterjet

Abstract: Experimental study of the surface quality produced by abrasive waterjet (AWJ) on metallic materials has been performed. The surface roughness/waviness was quantitatively evaluated by using the contactless optical measurement. In order to characterize the cut surface qualities, a single-parameter criterion has been proposed. Based on root mean square (RMS) roughness evaluation of the worst cut surface zone, the dimensionless statistical parameter C can be calculated as a basic quantity for AWJ surface cut characterization. As it was approved, besides its dependency on depth of AWJ trace, the value of C-parameter for the specific material is noticeably related also to the traverse speed of the cutting head. Such a relationship can be potentially used for adjusting the cutting speed of the machining process.