National Repository of Grey Literature 68 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Local velocity scaling in upward flow to tooth impeller in a fully turbulent region
Šulc, R. ; Ditl, P. ; Fořt, I. ; Jašíková, D. ; Kotek, M. ; Kopecký, V. ; Kysela, Bohuš
The hydrodynamics and flow field were measured in an agitated vessel using 2-D Time Resolved Particle Image Velocimetry (2-D TR PIV). The experiments were carried out in a fully baffled cylindrical flat bottom vessel 400 mm in inner diameter agitated by a tooth impeller 133 mm in diameter. Distilled water was used as the agitated liquid. The velocity fields were investigated in the upward flow to the impeller for three impeller rotation speeds – 300 rpm, 500 rpm and 700 rpm, corresponding to a Reynolds number in the range 94 000 < Re < 221 000. This means that fully-developed turbulent flow was reached. This Re range secures the fully-developed turbulent flow in an agitated liquid. In accordance with the theory of mixing, the dimensionless mean and fluctuation velocities in the measured directions were found to be constant and independent of the impeller Reynolds number. On the basis of the test results the spatial distributions of dimensionless velocities were calculated. The axial turbulence intensity was found to be in the majority in the range from 0.4 to 0.7, which corresponds to the middle level of turbulence intensity.
Measurement of drop size distribution time rate for liquid-liquid dispersion using IPI method
Jašíková, D. ; Kotek, M. ; Kysela, Bohuš ; Šulc, R. ; Kopecký, V.
The liquid-liquid dispersion properties are studied mainly by image analysis (IA) and Interferometric Particle Imaging (IPI). Drop sizes will be investigated in dilute dispersion since in this case the break up phenomena is the dominating and is not affected by phase fraction. Characteristics of the size distribution and the evolution of two liquid-liquid phase’s disintegration were studied. The IPI method was used for subsequent detailed study of the disintegrated droplets. We compared two liquids: Rhodosil Oil 47V50, and Silicone Oil AP1000 under stirrer rate of 540 rpm, and 760 rpm. The experiment run in the scaled model of agitated tank with Rushton turbine.
Turbulence characteristics scaling in Rushton turbine impeller discharge flow: effect of PIV system setup
Šulc, R. ; Ditl, P. ; Fořt, I. ; Jašíková, D. ; Kotek, M. ; Kopecký, V. ; Kysela, Bohuš
Study of mechanism of turbulent energy dissipation rate in the impeller discharge stream from a standard Rushhton turbine impeler in a model cylyndrical vessel with radial baffles.
Study of protein structure and dynamics by means of optical spectroscopy
Pazderka, Tomáš ; Kopecký, Vladimír (advisor) ; Kaminský, Jakub (referee) ; Setnička, Vladimír (referee)
Title: Study of protein structure and dynamics by means of optical spectroscopy Author: Tomáš Pazderka Institute: Institute of Physics of Charles University Supervisor: RNDr. Vladimír Kopecký, Ph.D., Institute of Physics of Charles University Abstract: The aim of this thesis is to improve understanding of protein structure and dynamics and extend experimental setup and data processing for such stud- ies. We focus on the extension of experimental feasability of vibrational optical activity (VOA). We have demonstrated a usability of intensity calibration in the field of Raman optical activity. Advantages for measurements on multiple instru- ments and/or using different configurations have been shown. A new instrumental setup has been developed for microsampling measurements of vibrational circular dichroism spectra with a spatial resolution of 1 mm. Using this technique, spatial inhomogeneities in a sample of protein fibrils have been observed. Model com- pounds for amide nonplanarity have been investigated utilizing several methods of optical spectroscopy and key spectral features for determination of amide non- planarity and the absolute configuration have been identified. A comprehensive set of Raman spectra of proteinogenic amino acids has been measured. Sample concentration dependencies and consequent...
Raman spectroscopy as the tool for Alzheimer's disease diagnostics
Tesař, Adam ; Kopecký, Vladimír (advisor) ; Jelínek, Otakar (referee)
Alzheimer disease (AD) is the most frequent dementia. The prevalence is approximately 10% in 65 years old people. The current treatment is only progression protective, therefore it is crucial to find a new diagnostic approach for diagnosing AD in early stage. We analysed a set of 55 patients by the drop coating deposition Raman spectroscopy with the goal to verify previously published high sensitivity of the AD spectroscopic diagnosis in cerebral spinal fluid (CSF) and to find a new diagnostic method for blood serum (BS). We optimized measurement conditions for BS. The results were evaluated by the cluster analysis and the principal component analysis. The small set of samples exhibited high sensitivity in both CSF and BS but that distinctly decreased in the whole set. The results for CSF were affected by the choice of the analysed spectral interval. The best for AD diagnose was the interval containing peaks at 980, 1080 and 1249 cm-1.The results for BS have been the most sensitive in the whole spectral range. They have low sensitivity but high specificity for AD (92%). The usage of neural networks has conversely high sensitivity and low specificity in both sets of samples of BS and CSF. Powered by TCPDF (www.tcpdf.org)
Atomic force microscopy in the region of biomacromolecules
Vančura, Martin ; Kopecký, Vladimír (advisor) ; Bednárová, Lucie (referee)
Atomic force microscopy (AFM) enables sample imaging at the micro and nanoscale. Recently, the method is applied to investigate biomacromolecules. Here, we describe the basic principles of AFM with a special emphasis for bioapplications. We tested experimental abilities of Alpha 300 - the Raman microscope with AFM/SNOM accessory from WITec company. The ability of AFM to study objects of cellular dimensions was demonstrated on erythrocytes and green algae Desmodesmus quadricauda. We were able to observe growing of lysozyme protein fibrils on day scale - from dimensions of seeds (~3 nm height) up to fibrils itself (3-10 nm height and 100 nm up to micrometers length). Subsequently, we observed separate protein molecules of thyroglobulin (~6 nm) and also γ-globulin (~3 nm). It seems plausible to image objects up to 2 nm dimensions by the given device with respect to the signal/noise ratio.
The minimum record time for PIV measurement in a vessel agitated by a Rushton turbine
Šulc, R. ; Ditl, P. ; Fořt, I. ; Jašíková, D. ; Kotek, M. ; Kopecký, V. ; Kysela, Bohuš
In PIV studies published in the literature focusing on the investigation of the flow field in an agitated vessel the record time is ranging from the tenths and the units of seconds. The aim of this work was to determine minimum record time for PIV measurement in a vessel agitated by a Rushton turbine that is necessary to obtain relevant results of velocity field. The velocity fields were measured in a fully baffled cylindrical flat bottom vessel 400 mm in inner diameter agitated by a Rushton turbine 133 mm in diameter using 2-D Time Resolved Particle Image Velocimetry in the impeller Reynolds number range from 50 000 to 189 000. This Re range secures the fully-developed turbulent flow of agitated liquid. Three liquids of different viscosities were used as the agitated liquid. On the basis of the analysis of the radial and axial components of the mean- and fluctuation velocities measured outside the impeller region it was found that dimensionless minimum record time is independent of impeller Reynolds number and is equalled N. t(Rmin) = 103 +/- 19.
Local velocity scaling in T400 vessel agitated by Rushton turbine in a fully turbulent region
Šulc, R. ; Ditl, P. ; Fořt, I. ; Jašíková, D. ; Kotek, M. ; Kopecký, V. ; Kysela, Bohuš
The hydrodynamics and flow field were measured in an agitated vessel using 2-D Time Resolved Particle Image Velocimetry (2-D TR PIV). The experiments were carried out in a fully baffled cylindrical flat bottom vessel 400 mm in inner diameter agitated by a Rushton turbine 133 mm in diameter. The velocity fields were measured in the zone in upward flow to the impeller for impeller rotation speeds from 300 rpm to 850 rpm and three liquids of different viscosities (i.e. (i) distilled water, ii) a 28% vol. aqueous solution of glycol, and iii) a 43% vol. aqueous solution of glycol), corresponding to the impeller Reynolds number in the range 50 000 < Re < 189 000. This Re range secures the fully-developed turbulent flow of agitated liquid. In accordance with the theory of mixing, the dimensionless mean and fluctuation velocities in the measured directions were found to be constant and independent of the impeller Reynolds number. On the basis of the test results the spatial distributions of dimensionless velocities were calculated. The axial turbulence intensity was found to be in the majority in the range from 0.388 to 0.540, which corresponds to the high level of turbulence intensity.
Never Born Proteins: Occurence and characterization of secondary structure motifs
Treťjačenko, Vjačeslav ; Hlouchová, Klára (advisor) ; Kopecký, Vladimír (referee)
An experimental study on randomly generated protein sequences can provide important insights into the origin and mechanism of secondary structure formation and protein folding. In this study we bring biophysical characterization of five protein sequences selected from the in silico generated library of random chains. The sequences were selected on the basis of bioinformatic analysis in order to find the candidates with the maximum potential to possess secondary structure. This study shows that the random polypeptide sequences form stable secondary structures and in some show the signs of tertiary structure, such as hydrophobic core formation and distinctive oligomerization pattern. While the work presented in this thesis is work in progress on a larger study, the data already demonstrate that unevolved protein sequence space provides a lot of potential for secondary and tertiary structure formation that awaits its characterization. Powered by TCPDF (www.tcpdf.org)
Characterization of proteins of 2'-5' oligoadenylate pathway by means of vibrational spectroscopy
Víšová, Ivana ; Kopecký, Vladimír (advisor) ; Bednárová, Lucie (referee)
The work concerns to structural characterization of two important proteins of 2'-5' oligoadenylate pathway participating in an immune response of organism to a viral infection. Studied proteins were ankyrin domain of mouse RNase L, the C-terminal part of human phosphodiesterase 12 and the complete human phosphodiesterase 12. The proteins were characterized by Raman spectroscopy, infrared spectroscopy, electronic circular dichroism, dynamic light scattering and in addition by two non-spectroscopic methods- differential calorimetry and electrophoresis. For each protein the secondary structures, thermal stability, weight of oligomers and generally a basic characterization by above mentioned methods were provided.

National Repository of Grey Literature : 68 records found   1 - 10nextend  jump to record:
See also: similar author names
1 Kopecký, V.
2 Kopecký, Vladimír
3 Kopecký, Vojtěch
2 Kopecký, Václav
1 Kopecký, Vít
Interested in being notified about new results for this query?
Subscribe to the RSS feed.