Impact of increasing energy efficiency of buildings on the acoustic properties of their claddings

Interdisciplinárne rezonujúcou témou v oblasti stavebnej fyziky je snaha znižovania energetickej náročnosti budov pri súčasne čo najnižšom možnom zaťažení ekosystému. Pokrok v materiálových, konštrukčných a technologických riešeniach umožňuje kontinuálne zvyšovanie kritérií na energetickú efektívnosť budov. Tu sa však ľahko môžeme stretnúť s komplikáciami v rámci konštrukčných riešení z pohľadu stavebnej akustiky ako aj s generovaním nežiadúceho hluku implementovaním technického vybavenia budov. V tomto príspevku sme sa snažili poukázať na vybrané prípady, s ktorými sa bežne môžeme stretávať v praxi. Podkladom tohto článku boli kapitoly 5.33 a 5.5 z knižne vydanej publikácie (Rychtáriková-Chmelík-Urbán, 2019).An interdisciplinary resonant topic in the field of building physics is the effort to reduce the energy intensity of buildings while at the lowest possible load on the ecosystem. Advances in material, construction and technological solutions enable the continuous increase of criteria for the energy efficiency of buildings. Here, however, we can easily encounter complications in structural solutions from the point of view of building acoustics as well as the generation of unwanted noise by implementing the technical equipment of buildings. In this paper, we have tried to point out selected cases that we can commonly encounter in practice. This article was based on Chapters 5.33 and 5.5 of the book published (Rychtáriková-Chmelík-Urbán, 2019)

Virtual reality system as a tool for education

Education in the field of computer graphics is attractive, but the necessity of strong theoretical background and the amount of work needed before achieving a non-trivial output could be discouraging for many students. To cope with inherent complexity of computer graphics applications, we designed a system intended to reduce implementation burden and help the students to achieve interesting results in less time. In our labs we use an in-house virtual reality system, which has been gradually improved by the work of our students and staff for a period of more than eight years. The foundation of the system is a modular architecture that allows rapid assembly of prototyped applications as well as easy implementation of extensions. Computer graphics students with even a fundamental level of knowledge are encouraged to participate in the lab projects. Working on system that allows rapid prototyping and shortens the path to achieving interesting visible results, builds up the students’ motivation and it is a key element of a continuous improvement during the study

Modifing the Surface Layers of Mechanical Components

This paper deals with the creation of thin surface layers prepared by the Plasma Assisted Chemical Vapour Deposition Method (PACVD). Polished sample surfaces made of tool steel were used. An investigation of the dependence of layer thickness on process duration was carried out. The structure of the original surface and the structure of the coated surface were evaluated and compared. The microhardness of the surface areas was also measured

Ultra-short TE STEAM improves hepatic lipid quantification and profiling at 7T

Previous 1H MRS measurements in the brain have demonstrated advantages of ultra-short TE at ultra-high fields. Besides higher SNR, T2 relaxation and J-modulation effects in the spectra can be minimized. This is of particular importance in the liver tissue, where both effects along with iron deposition have to be taken into account. The STEAM with TE=6ms provided higher SNR and reproducibility for precise estimation of HCL. Furthermore the high spectral resolution at 7T with sufficient CRLB´s of single lipid resonances highlights the potential of this sequence to be used in advanced studies of hepatic lipid profiles in vivo

Ultrashort-TE stimulated echo acquisition mode (STEAM) improves the quantification of lipids and fatty acid chain unsaturation in the human liver at 7 T

Ultrahigh-field, whole-body MR systems increase the signal-to-noise ratio (SNR) and improve the spectral resolution. Sequences with a short TE allow fast signal acquisition with low signal loss as a result of spin–spin relaxation. This is of particular importance in the liver for the precise quantification of the hepatocellular content of lipids (HCL). In this study, we introduce a spoiler Gradient-switching Ultrashort STimulated Echo AcqUisition (GUSTEAU) sequence, which is a modified version of a stimulated echo acquisition mode (STEAM) sequence, with a minimum TE of 6 ms. With the high spectral resolution at 7 T, the efficient elimination of water sidebands and the post-processing suppression of the water signal, we estimated the composition of fatty acids (FAs) via the detection of the olefinic lipid resonance and calculated the unsaturation index (UI) of hepatic FAs. The performance of the GUSTEAU sequence for the assessment of UI was validated against oil samples and provided excellent results in agreement with the data reported in the literature. When measuring HCL with GUSTEAU in 10 healthy volunteers, there was a high correlation between the results obtained at 7 and 3 T (R2 = 0.961). The test–retest measurements yielded low coefficients of variation for HCL (4 ± 3) and UI (11 ± 8) when measured with the GUSTEAU sequence at 7 T. A negative correlation was found between UI and HCL (n = 10; p < 0.033). The ultrashort TE MRS sequence (GUSTEAU; TE = 6 ms) provided high repeatability for the assessment of HCL. The improved spectral resolution at 7 T with the elimination of water sidebands and the offline water subtraction also enabled an assessment of the unsaturation of FAs. This all highlights the potential use of this MRS acquisition scheme for studies of hepatic lipid composition in vivo