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A light source with ligh emmiting diode
Novák, Matyáš ; Mojrová, Barbora (referee) ; Boušek, Jaroslav (advisor)
This work starts with the basic description of function of light-emitting diode. It also describes the basic techniques of design of cooling housings for power LEDs and possibility of heat removal. In the theoretical part of this work is also described the possibility of heat dissipation regulating and the possibility of the power sources for LEDs. The practical part includes description of LED light source design and construction, using knowledge about cooling and power from theoretical part. The light source is designed for different kinds of power supplies for maximum flexibility of usage.
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Magnetic properties of Ce compounds studied by specific heat
Čermák, Petr ; Javorský, Pavel (advisor) ; Havela, Ladislav (referee)
Materials containing the 4f (rare earth) or 5f (actinides) exhibit a large variety of interesting physical properties. The Ce-based compounds have a special place among the rare-earth compounds. The Ce atom contains only a single f-electron that is responsible for the magnetic behavior. The 4f states in compounds with the heavy rare earths have a well localized character, whereas many Ce-based compounds are on the borderline between the localized and itinerant behavior. These compounds show large variety of the magnetic ground states what is a result of the competition between the long-range order of the RKKY type and the screening of the localized moments by conduction electrons. We observe nonmagnetic states with a mixed valence (between Ce3+ and Ce4+), metallic systems with a long-range order of the Ce moments (ferromagnetic, antiferromagnetic or more complex structures). To analyze the electronic properties, the heat capacity data, and namely their low-temperature part, play an indispensable role. This diploma work comprise the sample preparation of selected cerium compounds, their phase characteristics and the heat capacity measurements at low temperatures (0.4 - 300 K). The main part is focused on the data analysis and comparison with theoretical models.
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Device Proposal for Measurement and Evaluation of Environmental Thermal State
Janečka, Jan ; Vdoleček, František (advisor)
The thesis deals with evaluation of the environmental thermal state in closed rooms with people inside the room. The achievement of thermal comfort is related to thermal balance of human body. People are producing heat during their work, which has to be carried away from the body to surrounding area by radiation, convection, conduction, respiration and evaporation. The intensity of heat removal is influenced by environmental parameters, especially by air temperature, mean radiant temperature, air velocity and humidity. Personal factors as energy expenditure of human body and clothing resistance are influencing the intensity of heat removal as well. People are able to influence the thermal comfort by their behaviour in given environment, appropriate clothing and regulation of basic environmental parameters. CSN EN ISO 7730 standard states that environmental parameters should be estimated or measured. The operative temperature is than evaluated from collected data. This operative temperature is defined as the temperature of black enclosed area where the human body will be by convection and radiation sharing the same amount of heat as in real inconsistent environment. Nowadays on the market there is no cheap solution for sensor which is able to evaluate the operating temperature and could be used in buildings. There are a lot of professional sensors which have very high accuracy, but are very expensive. Therefore are mainly used only for research or for single and exceptional measurement of environmental thermal state in rooms. The thesis is therefore focused on proposal of suitable (compact) operative temperature sensor assembled according to valid regulations and standards. Emphasis is placed mainly on the sensor price together with guarantee of sufficient accuracy. The proposed sensor is providing information to control system which is than able to adjust the parameters of environment using appropriate way based on relevant requirements. Here is some space for energy savings due to possible continuous measurement and evaluation of environmental thermal state in different rooms. Therefore, during continuous measurement no unnecessary rooms overheating in winter as well as unreasonable cooling in summer should occur. This research and solution is than reflected in reduction of energy consumption used for building operation and subsequently reduction of the pollutants production. This issue is being watched with increasing interest. Another advantage is that whole system is able to work autonomously without human intervention. People no longer have to continuously adjust air temperature because the control system is able to evaluate the most appropriate adjustments based on objective data obtained from the sensor. The thesis includes subsequent verification of proposed sensor as well as the definition of sensor technical parameters including analysis of measurement uncertainties.
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Microwave Melting Technology
Hájek, Milan
A new process of microwave glass heating reflects trends of glass industrial research towards ecological and energy saving aspects. Moreover, any glass cullets or raw batch materials can be melted by this microwave method. The quality of glass is saved during this process. However, the modification of glass to get a material of improved properties (e.g. mechanical resistance, morfology, microstructure) is possible and provides the opportunity to demonstrate glass blowing at exhibitions and fairs. The mobile furnace has been applied in laboratories, glass studios, glass works, and glass schools.
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Energy evaluation of office building.
Lysková, Markéta ; Horák, Petr (referee) ; Adam, Pavel (advisor)
This diploma thesis is dealing with energy audit of industrial building with administration part, situated in Blansko, South Moravia region. The theoretical part is focused to windows from the energy balance point of view, because one of the energy saving measures is the change of current insufficient window filling. The main objective of this diploma thesis is to find the most energy saving variant which is going to be evaluated from the both, ecological and economical, aspect. The third part is dedicated to usage of computer technology as software for 3D model creating of assessed building or energy consumption simulation for particular systems as heating in relation to characters of different kinds of windows.
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PHASE EVOLUTION IN Ni-48 at.% TI SHAPE MEMORY ALLOY PREPARED BY SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS
Karlík, M. ; Haušild, P. ; Beran, Přemysl ; Novák, P. ; Čapek, J. ; Kučera, V. ; Kopeček, Jaromír
In Ni rich Ni–Ti alloys, various phases such as hexagonal Ni3Ti, cubic NiTi2 and rhombohedral Ni4Ti3 appear during heat treatment. The presence of these precipitates affects the shape memory effect and superelasticity in an important manner. In this paper we present a study of the phase evolution during annealing of the Ni–48at.%Ti shape memory alloy elaborated by self-propagating high-temperature synthesis (SHS). Morphology and crystallography of the phases were examined by means of light metallography, scanning electron microscopy (SEM), neutron and X-ray diffraction, transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Besides the phases mentioned in the\nliterature, a Ni-rich phase with the composition near Ni3Ti2 stoichiometry and having a cubic symmetry was found. This phase develops from Ni4Ti3 particles during slow (furnace) cooling from the temperature of 1000 °C. Its particles have the form of thin platelets coherent with the (B2) NiTi matrix. The orientation relation is either cube-to-cube, [111]P || [115]B2 and (1-10)P || (1-10)B2 or [011]P || [011]B2 and (1-10)P || (1-41)B2.\n
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Structure and function of the vanilloid receptor TRPV1
Sušánková, Klára ; Vlachová, Viktorie (advisor) ; Kršiak, Miloslav (referee) ; Chvátal, Alexandr (referee)
2 11.. SSuummmmaarryy The vanilloid receptor (TRPV1) plays a role of the polymodal detector of nociceptive stimuli in a subset of small and medium sized primary sensory neurons in mammals. This channel can be activated by vanilloid compounds, low pH, and noxious heat, and its function is modulated by a wide range of endogenous and exogenous agents. Our results demonstrate that the reducing agent dithiothreitol (DTT) strongly potentiates both the native and recombinant rat TRPV1 channel when applied at millimolar concentrations to the external solution under intact whole-cell conditions. Since the effects of DTT were almost immediate, dose-dependent, and reversible, the contribution of extracellular cysteine residues within the putative pore-loop region of TRPV1, Cys616, Cys621, and Cys634 has been proposed. We show that the chemical modification of TRPV1 by both reducing and oxidizing agents leads to an increased response to heat. In addition, we identify the extracellularly located cysteine at position 621 which contributes to the DTT-induced potentiation of heat-activated currents mediated by TRPV1. Our data also indicate that capsaicin concentration is radically altered by the presence of oxidizing agents. More generally, the redox-active substances can substantially affect the activity of TRPV1 channels...
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Intradepartmental Accounting Standards And Their Problems In The Company Kočí, a. s.
KOŠATKOVÁ, Eliška
The aim of the graduation theses was acquaintance with the problems of intradepartmental regulations. In the theoretical part was described what legislations we use when we create the intradepartmental regulations. Laws are the theoretical basis for the creation of the intradepartmental regulations. The first part of each intradepartmental direct is created by these laws. The intradepartmental adjustment forms the second part of each intradepartmental direction. Here is a procedure developed by the accounting entities. These rules are a complement of the legislative regulation. The accounting entity creates these rules where the law gives it space for the intradepartmental solution of this problem. The graduation theses concerned the intradepartmental regulations of the building company KOČÍ, Inc. These regulations haven?t been updated for a long time. They were in a very limited extent. Therefore, I examined their topicality and complexity. Then I made the modification and designed changes of existing intradepartmental directions.
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Energetic utilization of wastewater
Žáček, Jan ; Raček, Jakub (referee) ; Hlavínek, Petr (advisor)
Diploma thesis presents various methods of energetic utilization of wastewater. It shows that wastewater is source of heat energy that has not been used yet. The thesis focuses mainly on heat recovery from wastewater from sewer bypass by modular heat exchangers. Design of heating of polyfunctional building from bypass from main sewer in Brno is developed. The main finding is that wastewater as low potential source of energy can together with heat pump be not only used for heating and heating of domestic hot water but also for cooling of polyfunctional object. Part of work is also technical-economical assessment by the NPV method.
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Selective Leaching as a Method of Metallic Nanoparticles Preparation
Michalcová, A. ; Vojtěch, D. ; Kubatík, Tomáš František ; Marek, I. ; Svobodová, P. ; Novák, P.
Selective leaching is process used mainly in analytical praxis–alloy matrix is dissolved and the residuum can be study by different methods. In this article, modification of selective leaching determined for production of metallic nanoparticles is described.Selective leaching technique lays in preparation of supersaturated solid solution of desired element in matrix metal –by convenient heat treatment or by rapid solidification of the binary alloy. Consequently, the matrix metal is selectively dissolved and metal nanoparticles from other metal are formed. The size, shape and agglomeration of forming metallic nanoparticles are dependent on many factors such as reaction temperature, concentration of leaching solution, additives present in leaching solution. The metal mainly used as matrix component is aluminium due to is amphoteric behaviour. It enables aluminium dissolution in sodium hydroxide without affecting the minor metal. Nobel metals like silver or copper forms
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