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: Fracture mechanics & Filter (video). 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.

Determination of bismuth by dielectric barrier discharge atomic absorption spectrometry coupled with hydride generation: method optimization and evaluation of analytical performance.

Abstract: Atomization of bismuth hydride in a 17 W planar quartz dielectric barrier discharge (DBD) atomizer was optimized and the performance of this device compared to that of a conventional quartz tube atomizer (QTA) for atomic absorption spectrometry (AAS). Modification of the inner surface of the DBD atomizer using dimethyldichlorsilane (DMDCS) was essential since it improved sensitivity by a factor of 2–4. Argon, at a flow rate of 125 mL min–1, was the best DBD discharge gas. Free Bi atoms were also observed in the DBD with nitrogen, hydrogen, and helium discharge gases but not in air. The detection limit for Bi (1.1 ng mL–1) is worse than with the QTA (0.16 ng mL–1 Bi). A poorer detection limit compared to a QTA is a consequence of the shorter optical path of the DBD. Moreover, the lower atomization efficiency and/or faster decay of free atoms in the DBD has to be considered. The performance of the DBD as an atomizer reflects both effects, i.e., atomization efficiency and free atom decay, was estimated to be...

Variational approximation of long-span language models for lvcsr

Abstract: Long-span language models that capture syntax and semantics are seldom used in the first pass of large vocabulary continuous speech recognition systems due to the prohibitive search-space of sentence-hypotheses. Instead, an N-best list of hypotheses is created using tractable n-gram models, and rescored using the long-span models. It is shown in this paper that computationally tractable variational approximations of the long-span models are a better choice than standard n-gram models for first pass decoding. They not only result in a better first pass output, but also produce a lattice with a lower oracle word error rate, and rescoring the N-best list from such lattices with the long-span models requires a smaller N to attain the same accuracy. Empirical results on the WSJ, MIT Lectures, NIST 2007 Meeting Recognition and NIST 2001 Conversational Telephone Recognition data sets are presented to support these claims.

KHN-equivalent voltage-mode filters using universal voltage conveyors

Abstract: The analog circuit design is very often focused on the design of frequency filters employing different types of active elements. In this paper we present the universal voltage conveyor that is used for the design of the KHN-equivalent filters working in the voltage-mode. Auxiliary voltage inputs of the active elements are used to reduce the number of floating admittances in the structure. Both proposed structures are easily cascadable since the input and output impedances are in theory infinitely high and zero, respectively. The behavior of the filters has been verified through PSpice simulations and furthermore by experimental measurements.

Detection of eccentricity and bearings fault using stray flux monitoring

Abstract: The article describes the possibilities of employment of external magnetic field for detection of rotor eccentricity and for bearing fault diagnosis. Proposed method uses the magnetic flux density in proximity of induction motor as a diagnostic signal and it reaches the relatively high sensitivity in case of rotating air gap asymmetry represented by dynamic eccentricity. Since the bearing fault is the most frequent type of failure, the feasibility of applying this method is investigated. The results of experimental tests are introduced, including the motors with dynamic eccentricity and with artificially damaged bearing on the inner race. Both the stray flux and stator current are measured and compared in frequency domain.

Multi-instrumental Analysis of Tissues of Sunflower Plants Treated with Silver(I) Ions - Plants as Bioindicators of Environmental Pollution.

Abstract: The aim of this work is to investigate sunflower plants response on stressinduced by silver(I) ions. The sunflower plants were exposed to silver(I) ions (0, 0.1, 0.5,and 1 mM) for 96 h. Primarily we aimed our attention to observation of basic physiologicalparameters. We found that the treated plants embodied growth depression, coloured changes and lack root hairs. Using of autofluorescence of anatomical structures, such aslignified cell walls, it was possible to determine the changes of important shoot and rootstructures, mainly vascular bungles and development of secondary thickening. Thedifferences in vascular bundles organisation, parenchymatic pith development in the rootcentre and the reduction of phloem part of vascular bundles were well observable.Moreover with increasing silver(I) ions concentration the vitality of rhizodermal cellsdeclined; rhizodermal cells early necrosed and were replaced by the cells of exodermis.Further we employed laser induced breakdown spectroscopy for determination of spatialdistribution of silver(I) ions in tissues of the treated plants. The Ag is accumulated mainlyin near-root part of the sample. Moreover basic biochemical indicators of environmentalstress were investigated. The total content of proteins expressively decreased withincreasing silver(I) ions dose and the time of the treatment. As we compare the resultsobtained by protein analysis - the total protein contents in shoot as well as root parts - wecan assume on the transport of the proteins from the roots to shoots. This phenomenon canbe related with the cascade of processes connecting with photosynthesis. The secondbiochemical parameter, which we investigated, was urease activity. If we compared theactivity in treated plants with control, we found out that presence of silver(I) ions markedlyenhanced the activity of urease at all applied doses of this toxic metal. Finally we studiedthe effect of silver(I) ions on activity of urease in in vitro conditions.