DYNAMIC BEHAVIOUR OF FLOOD GATES

Ve vodohospodářské praxi se často setkáváme s případy nežádoucích kmitání ocelových konstrukcí. Tyto nežádoucí vibrace jsou nepříjemné z hlediska šíření zvukové vlny do okolí a nebezpečné z hlediska negativního ovlivnění okolních částí a vlivu na cyklickou únavu materiálu. V případech jezových klapek dochází k nechtěnému chvění konstrukce nejen při zvýšených povodňových stavech, ale zejména při běžných či malých průtocích. Cílem výzkumu bylo vytipování manipulačních stavů a částí jezových uzávěrů náchylných na nežádoucí vibrace včetně popisu negativních vlivů na konstrukci a na okolí. Klapkové uzávěry mají mnoho výhod – rovnoměrné namáhání spodní stavby a podloží od zatížení, dobrá regulace hladiny ve zdrži, dobré hydraulické podmínky při sklopení klapky, úspora materiálu na výrobu a velmi vhodné statické působení. Statické výhody jsou v kontrastu s omezenou tuhostí subtilní konstrukce. Popis statického a dynamického působení klapky byl zkoumán na hydraulickém fyzikálním modelu klapky v laboratoři, na matematickém modelu a na skutečné klapce. Tyto metody výzkumu mají své přednosti i nedostatky, nicméně vhodným skloubením všech vědeckých postupů hybridního modelování lze z výzkumu získat mnoho zajímavých a pro praxi užitečných výsledků.In water management engineering practise it is often necessary to deal with undesirable vibrations which are observed on steel constructions at hydraulic structures. Such vibrations usually not only induce inconvenient noise but also influence the surrounding structures and fatigue life of the steel construction itself. Flap gates suffer with flow induced vibrations mainly during low or normal flow periods. An observation of vibrations during floods when the flap gates are lowered is relatively scarce. The completed research was focused on selection of the operating states, i.e. positions of the gate and discharge, and parts of the gate construction which are likely to suffer from undesirable vibrations. Detailed description of the negative impact on the gate was also part of the research. The use of flap gates in general presents several advantages such as even distribution of the load on foundation structure, good performance in water table regulation; favourable hydraulic conditions when the gate is lowered, construction material economy and convenient structural action. The structural advantages contrast with low compliance of the subtle structure. Both in situ experiments and physical modelling in laboratory were used for proper description of structural and dynamic behaviour of flap gates. Although certain merits and deficiencies can be attributed to both methods, a proper combination of different scientific approaches can result in interesting and in practise applicable conclusions

Suppressive Subtraction Hybridization on Stimulated Primary Horse Macrophages

To study genes potentially involved in genetic resistance to infectious diseases in the horse, suppressive subtraction hybridization was used to identify genes expressed in primary horse macrophages after their stimulation with E. coli. Overnight culture of blood monocyte-derived macrophage cells was stimulated with E. coli K12 in ratio 40 E. coli cells to one macrophage cell. After 4 hours of incubation, non-phagocyted bacteria were washed away. Following next 20 hour incubation in MEM alpha containing 5 μg of gentamycin in 1 ml of media, mRNA was isolated and used in Clontech PCR-Select cDNA Subtraction Kit. Expression of several known horse genes, as well as some new ESTs (expressed sequence tags) showing sequence similarity with immunity-related genes from other species was identified

PSG-Based Classification of Sleep Phases

This work is focused on classification of sleep phases using artificial neural network. The unconventional approach was used for calculation of classification features using polysomnographic data (PSG) of real patients. This approach allows to increase the time resolution of the analysis and, thus, to achieve more accurate results of classification

Model of Unmanned Ground Vehicle

The paper deals with utilization of the laser rangefinder for navigation and mapping of unknown indoor environment. The navigation algorithm is based on comparison of two pictures of the unknown space and gain of the correlation function maximum. The 2D position change of the rangefinder is calculated as a maximum of the correlation function. The goal is to improve the accuracy of odometric and inertial methods for localization and navigation of a robot system in an indoor environment

Sex differences in radioulnar contrasts of the finger ridge counts across 21 human population samples

Aim: The aim of the present study was to demonstrate the existence of uniform sexual dimorphism in some radioulnar contrasts between different finger ridge counts within the same hand in a large set of populations, thus confirming the universal nature of this dimorphism in humans.Subjects and methods: We analysed individual finger ridge counts (10 values on each hand) of both hands from archival sources (mainly the Brehme-Jantz database). In total, these included 4412 adults from 21 population samples covering all permanently inhabited continents and encompassing very different and geographically distant human populations. We calculated the contrasts (differences) of all pairs of ridge counts (45 per hand) and used diverse methods to assess the direction and degree of dimorphism of them across all population samples.Results: The highest sexual dimorphism was observed for nine contrasts involving the ridge count of the dermatoglyphic pattern on the radial side of the second finger of the right hand (R2r). Among these contrasts, we then found four that had the same direction of dimorphism in all 21 populations. The most dimorphic was the contrast R1rR2r – the difference between the ridge count of the radial side of the thumb and the radial side of the index finger.Discussion: Thus, these dermatoglyphic traits can be further investigated as potential markers of prenatal sex differentiation from ca. 10th week of intrauterine development. However, it will be useful to address the detailed factors and mechanisms for differences in the degree of dimorphism of these traits in different populations