Remarkable harvestmen from the Czech Republic

The fauna of harvestmen of the Czech Republic is relatively well-known (SILHAVY 1956, MARTENS 1978). Still, species new for the country have recently been found both in natural (KLlMES & BEZDECKA 1995) and synanthropic habitats (KLlMES 1995). Our knowledge of the distribution of most species is, however, far from complete. For several species, including ones found relatively frequently, only a few localities have been reported from the Czech Republic up to now. In this paper we present some interesting findings of harvestmen in Bohemia (western Czech Republic) and Moravia (eastern part) which may stimulate further faunistic research in the territory (fig. 1)

On application of least-delay variation problem in ethernet networks using SDN concept

The goal of this paper is to present an application idea of SDN in Smart Grids, particularly, in the area of L2 multicast as defined by IEC 61850-9-2. Authors propose an Integer Linear Formulation (ILP) dealing with a Least-Delay-Variation multicast forwarding problem that has a potential to utilize Ethernet networks in a new way. The proposed ILP formulation is numerically evaluated on random graph topologies and results are compared to a shortest path tree approach that is traditionally a product of Spanning Tree Protocols. Results confirm the correctness of the ILP formulation and illustrate dependency of a solution quality on the selected graph models, especially, in a case of scale-free topologies

Improving energy parameters of single-phase induction motors

Bakalářská práce Zlepšení energetických parametrů jednofázových asynchronních motorů se zabývá problematikou snížení ztrát u jednofázového asynchronního motoru J22VV506 od firmy ATAS Elektromotory Náchod a.s.. První část práce se zabývá teorií asynchronních motorů a je zde popsána problematika vzniku ztrát a jejich snížení. V druhé části je proměřen daný motor a vypočítána účinnost stroje a navrhnuty způsoby snížení ztrát. V poslední části je proměřen motor s navrženou úpravou.Bachelor thesis Improving energy parameters of single-phase induction motors deals with issues of lowering the losses of a small single-phase induction motor J22VV506 from ATAS Elektromotory Náchod a.s.. The first part deals with the theory of asynchronous motors and the issue of losses and their reduction is described in this part as well. In the second part engine parameters are measured and calculated efficiency of the machine and suggested ways to reduce losses. In the last part is measuring motor with the proposed regulation.

Graphic Engine with Scripting Support

Cílem této bakalářské práce je navrhnout řešení pro propojení zvoleného grafického enginu a skriptovacího jazyka. Tento návrh pak realizovat v demonstrační aplikaci a uvést další pokračování projektu.The objective of this bachelor's thesis is to propose solution for a cross connection between specific graphic engine and a skripting language. Implementation this proposal into a demo application and present further continuing of this project.

Sorption of metal ions mixture on natural lignite

Na jihomoravském lignitu byla prováděna sorpce čtveřice iontů kovů (Pb2+, Cu2+, Cd2+ a Zn2+). Z experimentů byla provedena sorpční kinetika, závislost sorpce na pH, závislost sorpce na počáteční koncentraci, závislost na teplotě, vliv přítomnosti elektrolytů (KNO3 a NaCl) a desorpce v deionizované vodě. Pro srovnání vlivu počáteční koncentrace na průběh sorpce kovů ze směsi byla provedena i sorpce kovů z roztoků obsahující pouze jeden sorbující se kov. Všechny experimenty byly provedeny vsázkovým způsobem. Doba sorpce byla 24 h, třebaže po dvou hodinách byla již koncentrace iontů blízko rovnováhy. Za optimální pH bylo zvoleno pH 5. Sorpcí kovů z jednosložkových roztoků bylo získáno pořadí jejich afinity k lignitu Pb >> Cd > Zn > Cu a v případě sorpce ze směsi Pb > Cu > Zn > Cd. Maximální adsorpční kapacita z jednosložkových roztoků byla pro Pb 97,82 mg/g, Cd 60,34 mg/g, Zn 49,88 mg/g a Cu 30,28 mg/g a v případě sorpce ze směsi byla pro Pb 39,03 mg/g, Cu 25,94 mg/g, Zn 15,21 mg/g a Cd 5,18 mg/g. Experimentální data byla proložena Langmuirovou a Freundlichovou izotermou. Byly vypočítány termodynamické veličiny H°, S° a G°. Desorpčním testem se ukázalo, že desorpční účinnost kovů je 0–3 %. Z elektrolytů vykazoval největší vliv na sorpci NaCl. Na základě získaných výsledků se zdá, že kovy jsou na lignitu vázány především chemickými interakcemi. Lignit je vhodným sorpčním materiálem pro ionty kovů, zvláště v oblasti nízkých koncentrací.Sorption of quaternary metal ions (Pb2+, Cu2+, Cd2+ and Zn2+) was carried out on lignite from the South Moravia. Following experiments were tested: kinetic sorption, dependence of sorption on pH, initial concentration, temperature, effect of electrolytes (KNO3 and NaCl) and desorption in deionized water. Sorption studies was carried out in quaternary mixtures and in the case of inicial concentration effect additional in a single-component solution. The batch sorption experiments was used. Sorption time was 24 hour, although concentration of ions was a near equilibrium after two hour. As the optimal pH was determined pH 5. The order of affinity by lignite was obtained Pb >> Cd > Zn > Cu for the sorption of metals in the single-component solution and the order was Pb > Cu > Zn > Cd for the sorption of mixture of metals. The maximum adsorptium capacities from single solutions were for Pb 97,82 mg/g, Cd 60,34 mg/g, Zn 49,88 mg/g and Cu 30,28 mg/g and in the case of ones from mixture solutions were for Pb 39,03 mg/g, Cu 25,94 mg/g, Zn 15,21 mg/g and Cd 5,18 mg/g. Experimental data have been analysed using Langmuir and Freundlich model. Thermodynamic values H°, S° and G° were calculated. Desorption test showed that desorption efficiency is 0–3 %. NaCl had the greatest influence on sorption from electrolytes. On the basis obtained results we can say that metals are binding to lignite in particular due to chemical interactions. Lignite is s suitable as a sorption material for metal ions especially in the field of low concentrations.

Fiber optic sensors

Semestrální práce se zabývá optikou, optickými vlákny a především optickými senzory, se kterými se v ní podrobněji seznámíme. Dále si představíme nový simulační program od firmy VPI photonics. Ukážeme si jeho uživatelské prostření a možnost simulace v něm.Term paper deals with optics, optical fibers and in particular with optical sensors, which are described in more detail. Furthermore, we introduce a new simulation program from VPI photonics. We will show the user interface and the possibiliti of sumulation in it.

Industrial PSD controller

Tato diplomová práce se zabývá principy měření teploty pomocí odporového teplotního snímače PT100 a návrhem algoritmu PSD regulátoru. Práce obsahuje popis problematiky měření teploty a způsob vyhodnocení pomocí mikrokontroléru, který pomocí PWM výstupu ovládá dodávaný tepelný výkon. Dále je zde popsán způsob realizace regulačního přístroje pro vytápění elektrické pece s ovládáním přes EthernetThis master’s thesis deal with principles temperature measurement using resistive temperature sensor PT100 and algorithm design PSD controler. In Work is includ description problems temperature measurement and way evaluation by means of mikrokontroler, which by PWM output controls supplied heat power. Next is here described method realization controls device for heating electric furnace with setup via Ethernet.

Impact of nodal centrality measures to robustness in Software-Defined Networking

The paper deals with the network robustness from the perspective of nodal centrality measures and its applicability in Software-Defined Networking (SDN). Traditional graph characteristics have been evolving during the last century, and numerous of less-conventional metrics was introduced trying to bring a new view to some particular graph attributes. New control technologies can finally utilize these metrics but simultaneously show new challenges. SDN brings the fine-grained and nearly online view of the underlying network state which allows to implement an advanced routing and forwarding. In such situation, sophisticated algorithms can be applied utilizing pre-computed network measures. Since in recent version of SDN protocol OpenFlow (OF) has been revived an idea of the fast link failover, the authors in this paper introduce a novel metric, Quality of Alternative Paths centrality (QAP). The QAP value quantifies node surroundings and can be with an advantage utilized in algorithms to indicate more robust paths. The centrality is evaluated using the node-failure simulation at different network topologies in combination with the Quality of Backup centrality measure

Fault tolerant ethernet based network for time sensitive applications in electrical power distribution systems

The paper analyses and experimentally verifies deployment of Ethernet based network technology to enable fault tolerant and timely exchange of data among a number of high voltage protective relays that use proprietary serial communication line to exchange data in real time on a state of its high voltage circuitry facilitating a fast protection switching in case of critical failures. The digital serial signal is first fetched into PCM multiplexer where it is mapped to the corresponding E1 (2 Mbit/s) time division multiplexed signal. Subsequently, the resulting E1 frames are then packetized and sent through Ethernet control LAN to the opposite PCM demultiplexer where the same but reverse processing is done finally sending a signal into the opposite protective relay. The challenge of this setup is to assure very timely delivery of the control information between protective relays even in the cases of potential failures of Ethernet network itself. The tolerance of Ethernet network to faults is assured using widespread per VLAN Rapid Spanning Tree Protocol potentially extended by 1+1 PCM protection as a valuable option

The taming of Clar's hydrocarbon

Triangulene is the smallest non-Kekulé graphene fragment known as Clar's hydrocarbon. Due to its open-shell electronic structure, triangulene is a promising molecular building block of carbon-based organic materials for spintronics and quantum molecular science. It comprises six benzenoid rings arranged in a triangular shape with two unpaired electrons delocalized over the entire conjugated core, making this molecule highly reactive. A triplet ground state is predicted for this hydrocarbon by Ovchinnikov's rule, or Lieb's theorem, in accord with Hund's rule. The pioneering work on triangulene was performed almost 70 years ago by Erich Clar, who attempted to prepare the pristine compound. Since then, several synthetic approaches to prepare this molecule have been exploited. The extreme reactivity of triangulene can be circumvented using on-surface techniques or by installation of sterically demanding substituents, which kinetically stabilize the diradical core against oligomerization in solution. The first two examples of a persistent derivative of triangulene were simultaneously and independently developed last year. This article presents a historical development in the synthesis of triangulene and its derivatives and outlines possible future applications in ferromagnetic materials, electrically conductive polymers or quantum computing