Papers

Latest additions:
2021-04-11
00:00

Detailed record
2021-04-11
00:00

Detailed record
2021-04-11
00:00
Antibacterial electrospun membrane prepared from poly(vinylidene fluoride)-co-hexafluoropropylene with lauric acid monoacylglycerol
Zelenková, Jana ; Peer, Petra ; Pleva, P. ; Janalíková, M. ; Sedlaříková, J. ; Filip, Petr
The aim of this study was to prepare an antibacterial nanofibrous membrane using electrospinning technique. The nanofibrous membranes were spun from polymer solution of poly(vinylidne fluoride)-co-hexafluoropropylene (PVDF-co-HFP) dissolved in N,N´-dimethylformamide. Monoacylglycerol of lauric acid (MAG C12) was used as an antimicrobial agent at the concentrations ranging from 1 to 3 wt%. The impact of MAG C12 incorporation on the rheological, structural and antibacterial properties was investigated. The rheological tests of polymer solutions, as steady shear and oscillatory shear, proved that addition of MAG C12 changed marginally rheological quantities such as viscosity, elastic (storage) and viscous (loss) moduli. Measurement of mean nanofibres diameter indicated a slight decrease with increasing MAG C12 concentration. Antimicrobial activity of PVDF-co-HFP nanofibre membranes with incorporated MAG C12 against Gram-positive bacteria Staphylococcus aureus and Gram-negative Escherichia coli was studied. An antibacterial activity was revealed for the samples containing MAG C12 at all concentrations against Gram-positive bacteria Staphylococcus aureus by the disk diffusion method.

Detailed record
2021-03-28
00:01
Staré kulturní krajiny Moravy
Kolejka, Jaromír
Vletech 2016-2020 proběhla na historickém území Moravy inventarizace segmentů krajiny, jejichž vzhled vsoučasné době je podobný jejich obrazu vpředindustriálním období na katastrálních mapách z1. pol. 19. st. Při řešení projektu programu NAKI MK ČR bylo do obsáhlé databáze zařazeno 1139 segmentů staré předindustriální krajiny větších než 10 ha. Navíc ke každému segmentu bylo zjištěno kolem 10 dalších charakteristik, které slouží geostatistické analýze a klasifikaci. Vpříspěvku je nastíněn myšlenkový postup identifikace zbytků staré kulturní krajiny počínaje přehledem nejstarších použitelných mapových podkladů zúzemí Moravy. Vysvětlen je pojem starobylá předindustriální krajina a zdůvodněno její časové zařazení. Zevrubně jsou popsány historické události, které předcházely vzniku předindustriální krajiny. Uvedeny jsou rovněž příčiny, které vedly kdramatickým změnám kulturní krajiny vdobě průmyslové společnosti. Nastíněn je postup zjišťování a mapování starých krajin za využití současné barevné ortofotomapy a císařských otisků katastrálních map z 20. - 30. let 19. století. Přiložená mapová dokumentace poskytuje přehled o charakteru dostupných podkladů o starých krajinách a o rozmístění jejich zjištěných zbytků na historickém území Moravy ve východní části České republiky.

Detailed record
2021-03-28
00:01
Odůvodnění trestů jako jediná manifestace diskrece při ukládání trestů: nový přístup k tradičnímu institutu
Drápal, Jakub
Českým soudům je často vytýkána nedostatečná úroveň odůvodňování trestů. Byť došlo k novelizaci trestního řádu upřesňující tuto povinnost a v odborné literatuře je její praxe často kritizována, kvalita odůvodnění uloženého trestu je tristní. V tomto příspěvku proto nejen rekapituluji důvody, proč je nutné detailně odůvodňovat tresty a empirické výzkumy zkoumající odůvodňování, ale představuji i teoretická východiska, dle kterých by odůvodnění mělo být strukturováno. Tyto závěry následně přetavuji do praxe, když navrhuji výrazně odlišný způsob, jak by bylo možné odůvodňovat tresty. Navrhovaný způsob odůvodňování je procesně jednodušší, posiluje kontradiktornost trestního řízení a zejména vede soudce a státní zástupce, aby ukládali či navrhovali tresty po důkladném zvážení všech okolností.

Detailed record
2021-03-28
00:01
Creation and Validation of Pressure Loss Model for Steam Turbine Control Valves
Sláma, V. ; Mrozek, L. ; Tajč, L. ; Šimurda, David ; Hála, Jindřich
In this paper, a creation and a validation of the pressure loss model for the specific and widely used design of the steam turbine inlet control valve assembly called an L-valve is described. This model is based on a wide range of experimental measurements on the valve model installed in an air tunnel and it is validated by numerical simulations using the commercial code. The results of experimental measurements as well as numerical simulations are shown. Furthermore, differences between experimental and numerical results are discussed. According to the results, the pressure loss model in the form of a smart and effective procedure for calculating the valve assembly pressure losses and choosing an optimal valve sizes has been created.\n

Detailed record
2021-03-28
00:01
Development of CFD solver for four-way coupled particle-laden flows
Šourek, M. ; Isoz, Martin
Computational uid dynamics (CFD) simulations containing freely moving bodies are still a challenging topic. More so, if the bodies are large enough to a_ect the uid ow and distributed\ndensely enough to come in contact both with the boundaries of the computational domain and with each other. In this work, we concentrate on the topic of simulation of (i) irregular bodies\nwith ow-induced movement and contact with computational domain boundaries taken into account, and (ii) bodies entrained by the uid and coming in contact not only with the domain\nboundaries but also with each other. The developed modeling approach is based on the hybrid _ctitious domain-immersed boundary method extended by the discrete element method. The\npresent contribution is focused on presentation of simulation principles and results of initial benchmark cases.

Detailed record
2021-03-28
00:01
POD-DEIM-based model order reduction for four-way coupled fluid-solid flows
Isoz, Martin ; Šourek, M.
Proper orthogonal decomposition (POD) and discrete empirical interpolation method (DEIM) have become established tools for model order reduction in simulations of fluid flows. However, including moving solid bodies in the computational domain poses additional issues with respect to the fluid-solid coupling and to the solution of the movement of the solids. Still, it seems that if the hybrid ctitious domain-immersed boundary method is used to include the solids in the flow domain, POD-DEIM based approaches may be extended for four-way coupled particleladen flows. The present work focuses on the construction of POD-DEIM based reduced order models for the aforementioned flows.

Detailed record
2021-03-28
00:01
Geometrically realistic macro-scale model for multi-scalesimulations of catalytic filters for automotive gasaftertreatment
Hlavatý, Tomáš ; Isoz, Martin ; Plachá, M. ; Šourek, M. ; Kočí, P.
This paper is part of a research focused on simulating (i) the catalytic conversion of environment endangering gases, and (ii) trapping of the particulate matter in automotive exhaust gas aftertreatment. Historically, the catalytic conversion and the filtration of soot particles were performed in independent devices. However, recent trend is to combine the catalytic converter and soot filter into a single device, the catalytic filter. Compared to the standard two-device system, the catalytic filter is more compact and has lower heat losses. Nevertheless, it is highly sensitive to the catalyst distribution. This study extends our recently developed methodology for pore-scale simulations of flow, diffusion and reaction in the coated catalytic filters. The extension consists of enabling data transfer from macro- to pore-scale models by preparing geometrically realistic macro-scale CFD simulations. The simulation geometry is based on XRT scans of real-life catalytic filters. The flow data from the newly developed macro-scale model are mapped as boundary conditions into the pore-scale simulations and used to improve the estimates of the catalytic filter filtration efficiency.

Detailed record
2021-03-28
00:01
Deep learning for magnetic resonance spectroscopy quantification: A time frequency analysis approach
Shamaei, Amirmohammad
Magnetic resonance spectroscopy (MRS) is a technique capable of detecting chemical compounds from localized volumes in living tissues. Quantification of MRS signals is required for obtaining the metabolite concentrations of the tissue under investigation. However, reliable quantification of MRS is difficult. Recently deep learning (DL) has been used for metabolite quantification of MRS signals in the frequency domain. In another study, it was shown that DL in combination with time-frequency analysis could be used for artifact detection in MRS. In this study, we verify the hypothesis that DL in combination with time-frequency analysis can also be used for metabolite quantification and yields results more robust than DL trained with MR signals in the frequency domain. We used the complex matrix of absolute wavelet coefficients (WC) for the time-frequency representation of the signal, and convolutional neural network (CNN) implementation for DL. The comparison with DL used for quantification of data in the frequency domain is presented.

Detailed record