National Repository of Grey Literature 4 records found  Search took 0.00 seconds. 
Computed tomography system with strict real-time synchronization for in-situ 3D analysis of periodically vibrating objects
Rada, Václav ; Fíla, Tomáš ; Zlámal, Petr ; Koudelka_ml., Petr ; Šleichrt, Jan ; Macháček, Michael ; Vavřík, Daniel ; Kytýř, Daniel
In the contribution, we present a laboratory system capable of X-ray computed tomography (XCT) scanning of an periodically moving or oscillating object. The system is an in-house developed XCT setup with electromagnetic voice coil actuator mounted on top of the rotary stage of the setup. The strict synchronization of the components, the rotary stage, the electromagnetic actuator movement and the detector readout is accomplished with use of the detector hardware trigger and hard real-time Linux operating system. Cylindrical sample manufactured from epoxy resin with metal particles to enable movement tracking is scanned in a stationary position and during periodical movement induced by the vibration stage. The volumetric data of the scans is compared and the results of this contribution represent an important step towards identification of defects through modal analysis of in-situ harmonically vibrating object.
Deformation response of polydimethylsiloxane substrates subjected to uniaxial quasi-static loading
Vinařský, V. ; Martino, F. ; Forte, G. ; Šleichrt, Jan ; Rada, Václav ; Kytýř, Daniel
To investigate cellular response of cardiomyocytes to substrate mechanics, biocompatible material with stiffness in physiological range is needed. PDMS based material is used for construction of microfluidic organ on chip devices for cell culture due to ease of device preparation, bonding, and possibility of surface functionalization. However it has stiffness orders of magnitude out of physiological range. Therefore, we adapted recently available protocol aiming to prepare substrates which offer stiffness in physiological range 5−100 kPa using various mixtures of Sylgard. An in-house developer loading device with single micron position tracking accuracy and sub-micron position sensitivity was adapted for this experimental campaign. All batches of the samples were subjected to uniaxial loading. During quasi-static experiment the samples were compressed to minimally 40% deformation. The results are represented in the form of stress-strain curves calculated from the acquired force and displacement data and elastic moduli are estimated.
Multi-channel control system for in-situ laboratory loading devices
Rada, Václav ; Fíla, Tomáš ; Zlámal, Petr ; Kytýř, Daniel ; Koudelka_ml., P.
In recent years, open-source applications have replaced proprietary software in many fields. Especially open-source software tools based on Linux operating system have wide range of utilization. In terms of CNC solutions, an open-source system LinuxCNC can be used. However, the LinuxCNC control software and the graphical user interface (GUI) could be developed only on top of Hardware Abstraction Layer. Nevertheless, the LinuxCNC community provided Python Interface, which allows for controlling CNC machine using Python programming language, therefore whole control software can be developed in Python. The paper focuses on a development of a multi-process control software mainly for in-house developed loading devices operated at our institute. The software tool is based on the LinuxCNC Python Interface and Qt framework, which gives the software an ability to be modular and effectively adapted for various devices.
Solution of soil protection from erosion in model catchment - Malče Budský stream.
RADA, Václav
The aim of this thesis is to assess and evaluate the erosion phenomena at the model catchment of Malče Budský stream. This site is located on the cadastral areas Besednice, Soběnov and Malče. This survey was conducted in aspects of pedology, hydrogeology and climate. Further evaluations were rain amount for the nearest meteorological station, which is located in Soběnov. To evaluate and calculate erosion parameters for a given locality the methods of universal soil loss equation by Wishmeier and Smith and modified universal soil loss equation by Williams and Berndt have been used. The CN method was used for calculations and following evaluation of soil loss. The result of this thesis is designing, generalization and refinement of individual factors in solved area.

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5 Rada, Václav
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