National Repository of Grey Literature 64 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
The Influence of Operating Parameters and Construction Parameters of the Process Burner on Stability and Combustion Processes Parameters
Skryja, Pavel ; Jegla, Zdeněk (referee) ; Odstrčil, Miloslav (referee) ; Stehlík, Petr (advisor)
The objectives of this paper focus upon composing recommendations with respect to burners design while observing aerodynamic, together with present and advanced developments in the field of flame technology principles. Specifically the aims are set at flame stability and pollutions. Important part of this paper is a novel design procedure dealing with premixed burners. Further, by exploiting the results of testing program enabled one to design burners exhibiting low level of nitrogen oxides emissions. On the basis of aerodynamic analysis of premixed burners flow path several recommendations on the geometry resulted in proposing two ejectors, which transport the combustion air. In the first ejector the fuel jet, generated by flow through a nozzle, draws the specified part of the combustion air, and then the mixture is a driving agent of the second ejector. The remaining part of combustion air flows first through the radial curved vanes, and second its tangential velocity component is augmented by axial vanes prior it enters mixing part of the second ejector. For the additional contribution to the rotating motion the inclined axial vanes built inside the nozzle of the second ejector are responsible. The resulting swirling number reaches the values up to 2.6. For the burner so arranged fire stability and low NOx emissions in the wide operating conditions can be expected. Within the frame of extensive testing program in the field of diffusion burners several modifications have been carried out such as setting of axial vanes which secure the swirling motion, changes of combustion air flows path, and modifications of secondary nozzles, these resulted in extending zone of stabilized flame and reducing the formation of NOx, e.g. NOx emissions of 70 ppm, prior the modifications, have dropped to 30 ppm (dry flue gas 3% O2). The main contribution of this paper stands in applications of development activities results in aerodynamic and flame within their implementation in the field of burners design. Further, it is the proposed design of burners which are capable of simultaneously firing products of the biomass microwave pyrolysis, namely syngas and bio-oils.
Methods for Determination of Characteristic Parameters of Combustion Processes on the Basis of Experiments and Modeling
Bělohradský, Petr ; Klemeš,, Jiří (referee) ; Žitný, Rudolf (referee) ; Stehlík, Petr (advisor)
The present thesis is concerned with methods for determination and modeling of characteristic parameters of combustion of gaseous fuels. The focus is stressed on formation of nitrogen oxides and heat transfer from hot flue gases into combustion chamber’s walls. Experimental work, which is focused on testing of two burners with suppressed formation of nitrogen oxides, is an important part of the thesis. Its aim is to obtain data that is necessary for further processing and modeling. The work presents two methods that may be used in modeling of characteristic combustion parameters, namely the method based on statistical processing of data and the method based on computational fluid dynamics. The approaches are applied to two devices (burner with two-staged fuel supply, burner with two-staged air supply) with the objective to analyze their parameters. First approach covers detailed planning of burner test prior to its own carrying out (definition of the goal of experiment, choice of input factors and response, experimental plan) and subsequent statistical processing of experimental data. On the contrary, CFD approach offers simulations as an alternative option to traditional experimental methods. The simulation of combustion includes building of computational grid, setup of boundary conditions, turbulence model, heat transfer model and chemical kinetics. Results of simulations are compared with experimental measured data.
Effective Utilization of Municipal Solid Waste in Heat and Power Systems
Ferdan, Tomáš ; Bébar, Ladislav (referee) ; Ucekaj, Vladimír (referee) ; Stehlík, Petr (advisor)
This work focuses on effective utilization of municipal solid waste in heat and power systems. The effectivity in this work is evaluated from an economic as well as an environmental viewpoint. In the introductory part a review of legislation and state-of-the art in the fields of energetics and waste management of European Union is presented. Next an optimization tool NERUDA, created on the author’s workplace, is introduced. NERUDA consists of basic modules on which creation has the author been participating. The thesis is divided into two main parts that describe two NERUDA’s modules. First deals with a techno-economic model of waste-to-energy plants and is called Flexi model. The main output is a dependency of gate fee on capacity. Second part is devoted to the implementation of new module into the NERUDA system. This module is an environmental criterion for evaluation of the effectivity of waste utilization in the waste management and energetics.
The FITkit3 Tester
Stehlík, Petr ; Strnadel, Josef (referee) ; Bidlo, Michal (advisor)
This work solves the problem of testing a certain set of ARM Kinetis Cortex-M4 \newline (MK60DN512ZVMD10) microcontroller modules on the FITkit3 learning platform (also known as Minerva). Specifically, it deals with the design of test firmware in the C programming language for automated testing, the design of a hardware module for testing platform input/output interfaces using the MCP23S17 integrated circuit and the design of a software with text-based user interface in Python3 for the testing control from a PC. The selected test set of modules are Periodic interrupt timers (PIT), Low-power timer (LPTMR) and Real time clock (RTC), further modules for serial data transmission via UART and SPI interfaces, speaker and GPIO ports. The created solution provides a comprehensive tool for analysing the functionality of frequently used modules on FITkit3, which automates the analysis process almost completely. The main benefit of this work is the facilitation of testing and a rapid detection of errors in a large number of kits.
Direct penalisation of overloaded vehicles based on HS WIM systems
Stehlík, Petr ; Doupal,, Emil (referee) ; Smělý, Martin (advisor)
This master's thesis deals with systems and technology of high speed weigh in motion stations. The main task is to evaluation of accuracy different sensor installations of weight in motion stations. A part of this thesis is an analysis of different sensor types, which are used for stations equipped with technology for enforcement, and evaluation of accuracy of axle distance measurement.
Putna, Ondřej ; Klemeš, Jiří (referee) ; Ucekaj, Vladimír (referee) ; Stehlík, Petr (advisor)
The dissertation thesis is focused on the issue of energy recovery of waste. It contributes to optimization models developed in the author's workplace in the long term, which serve to simulate material flows in waste management and to search for an optimal waste management strategy. The main objective is to assess the potential for the use of heat produced in waste-to-energy plants as a key factor for the economy of these facilities. The thesis therefore represents an activity on the border of the fields of waste management and heating. Partial mathematical models were developed within the scope, for which it was necessary to collect input data, especially in relation with district heating networks. These models were then used in a comprehensive optimization model describing the integration of waste-to-energy plants with other heat sources. This main model was extended to include the environmental aspect.
Diagnostics of structures in the evaluation of faults and defects
Stehlík, Petr ; Kocáb, Dalibor (referee) ; Schmid, Pavel (advisor)
This bachelor's thesis deals with research into methods of measuring and evaluating faults and defects in structures. A part of this thesis is an analysis of the legal issues in regard to investigations of structural defects in buildings. This thesis also includes a practical study of a family house in Černopolní street, which was affected by masonry cracks. The study details the collection and processing of data and analysis of the possible causes of the failures.
Complex Waste Collection Models
Nevrlý, Vlastimír ; Šenkeřík, Roman (referee) ; Procházka,, Vít (referee) ; Stehlík, Petr (advisor)
The subject of this doctoral thesis is the solution of logistics systems in the context of waste management. The work begins with an extensive research in the field of modelling various situations from the waste transportation chain. There are presented multiple types of practical tasks in the area of operation research applicable to waste management. Their possibilities of extension and modification are analysed for use by investors, technical services or waste collection service providers. An essential part of the work is the identification of critical parameters in the waste collection at the level of municipalities and micro-regions. Based on practical requirements, challenges related to the improvement of decision-making and planning systems are defined. The available techniques proved to be insufficient for practical problems. For the area of changes and designs of collection systems (design and modification of routes, choice of the vehicle fleet, collection plan, etc.) there are no procedures that would include a whole range of operating conditions and parameters. The boundary conditions of the task affecting fundamental requirements are highly variable. The thesis presents a comprehensive approach, which is divided into several phases. The preparation and analysis of input data focused mainly on the creation of transport infrastructure, allocation of waste collection containers and their pairing to the network, which also reduces the size of the task. Furthermore, a procedure for compliance with the rules of the road was designed using a penalty function, and an algorithm for defining imaginary edges was implemented, which will allow distinguishing the frequency of collection on selected network segments. To reduce the size of the task, a segment clustering algorithm was also designed, which will enable the calculation of the collection even for larger areas. Input parameters related to operating time and fullness of collection containers are elaborated in greater detail, as they most influence the results of the task. A great benefit is also the algorithm generating the initialization solution from historical routes. As part of the related publishing activities, environmental criteria were defined to evaluate global and local impacts of waste transportation and treatment. The outputs of the thesis are used primarily for the analysis of collection systems, to support the deployment of waste containers, planning collection routes, time schedules and dimensioning the size of the vehicle fleet. The proposed algorithms were tested in several case studies, which proved the broad applicability of a comprehensive tool in the field of waste logistics. Although the thesis is focused on modelling the collection of municipal waste, the usability of the implemented procedures is possible in other areas of waste management or other sectors.
Advanced Logistic Models for Waste Management
Gregor, Jiří ; Jegla, Zdeněk (referee) ; Pospíšil,, Karel (referee) ; Stehlík, Petr (advisor)
The purpose of the dissertation thesis is to prepare transport techno-economic models which will be able to estimate the transportation cost for selected scenarios. The main goal is to describe the complex transport chains in waste management, using different types of transportation (road, rail) and transport different types of waste. The key element of preparing techno-economic models is the identification of input parameters which are important for estimating the cost of transport. At the same time, it is necessary to correctly identify the processing facilities that will be part of complex transport chains. The total outputs will be presented in the form of a feasibility study.
Analysis of Operational Data and Detection od Anomalies during Supercomputer Job Execution
Stehlík, Petr ; Nikl, Vojtěch (referee) ; Jaroš, Jiří (advisor)
V posledních letech jsou superpočítače stále větší a složitější, s čímž souvisí problém využití plného potenciálu systému. Tento problém se umocňuje díky nedostatku nástrojů pro monitorování, které jsou specificky přizpůsobeny uživatelům těchto systémů. Cílem práce je vytvořit nástroj, nazvaný Examon Web, pro analýzu a vizualizaci provozních dat superpočítače a provést nad těmito daty hloubkovou analýzu pomocí neurálních sítí. Ty určí, zda daná úloha běžela korektně, či vykazovala známky podezřelého a nežádoucího chování jako je nezarovnaný přístup do operační paměti nebo např. nízké využití alokovaých zdrojů. O těchto  faktech je uživatel informován pomocí GUI. Examon Web je postavený na frameworku Examon, který sbírá a procesuje metrická data ze superpočítače a následně je ukládá do databáze KairosDB. Implementace zahrnuje disciplíny od návrhu a implementace GUI, přes datovou analýzu, těžení dat a neurální sítě až po implementaci rozhraní na serverové straně. Examon Web je zaměřen zejména na uživatele, ale může být také využíván administrátory. GUI je vytvořeno ve frameworku Angular s knihovnami Dygraphs a Bootstrap. Uživatel díky tomu může analyzovat časové řady různých metrik své úlohy a stejně jako administrátor se může informovat o současném stavu superpočítače. Tento stav je zobrazen jako několik globálně agregovaných metrik v posledních 30 minutách nebo jako 3D model (či 2D model) superpočítače, který získává data ze samotných uzlů pomocí protokolu MQTT. Pro kontinuální získávání dat bylo využito rozhraní WebSocket s vlastním mechanismem přihlašování a odhlašování konkretních metrik zobrazovaných v modelu. Při analýze spuštěné úlohy má uživatel dostupné tři různé pohledy na danou úlohu. První nabízí celkový přehled o úloze a informuje o využitých zdrojích, času běhu a vytížení části superpočítače, kterou úloha využila společně s informací z neurálních sítí o podezřelosti úlohy. Další dva pohledy zobrazují metriky z výkonnostiního energetického hlediska. Pro naučení neurálních sítí bylo potřeba vytvořit novou datovou sadu ze superpočítače Galileo. Tato sada obsahuje přes 1100 úloh monitorovaných na tomto superpočítači z čehož 500 úloh bylo ručně anotováno a následně použito pro trénování sítí. Neurální sítě využívají model back-propagation, vhodný pro anotování časových sérií fixní délky. Celkem bylo vytvořeno 12 sítí pro metriky zahrnující vytížení procesoru, paměti a dalších části a např. také podíl celkového času procesoru v úsporném režimu C6. Tyto sítě jsou na sobě nezávislé a po experimentech jejich finální konfigurace 80-20-4-3-1 (80 vstupních až 1 výstupní neuron) podávaly nejlepší výsledky. Poslední síť (v konfiguraci 12-4-3-1) anotovala výsledky předešlých sítí. Celková úspěšnost  systému klasifikace do 2 tříd je 84 %, což je na použitý model velmi dobré. Výstupem této práce jsou dva produkty. Prvním je uživatelské rozhraní a jeho serverová část Examon Web, která jakožto rozšiřující vrstva systému Examon pomůže s rozšířením daného systému mezi další uživatele či přímo další superpočítačová centra. Druhým výstupem je částečně anotovaná datová sada, která může pomoci dalším lidem v jejich výzkumu a je výsledkem spolupráce VUT, UNIBO a CINECA. Oba výstupy budou zveřejněny s otevřenými zdrojovými kódy. Examon Web byl prezentován na konferenci 1st Users' Conference v Ostravě pořádanou IT4Innovations. Další rozšíření práce může být anotace datové sady a také rozšíření Examon Web o rozhodovací stromy, které určí přesný důvod špatného chování dané úlohy.

National Repository of Grey Literature : 64 records found   1 - 10nextend  jump to record:
See also: similar author names
29 STEHLÍK, Petr
2 Stehlík, Patrik
6 Stehlík, Pavel
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