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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Návrh optovláknového tepelného senzoru pro detekce narušení obranného perimetru / Design of optical fiber temperature sensor for detection of defense perimeter

Zámečník, Ondřej January 2021 (has links)
This diploma thesis deals with the issue of measuring the ambient temperature using a~single-mode optical fiber used as a temperature sensor. The thesis describes the basic knowledge about polarized light, its propagation in optical fiber and describes special fibers that preserve polarization. It also deals with the representation of polarization states on a Poincaré sphere and the use of Stokes and Jones vectors. In the practical part, several selected methods of optical signal supply to the temperature sensor are measured. Subsequently, the suitability of the given methods is evaluated from the measured results and the courses are compared with the records measured from real routes. This thesis aims to select a suitable connection of a temperature sensor for a long route of optical fiber and verify its functionality.
52

Systém řízení slunečních kolektorů / Systme for solar system control

Cseri, Peter January 2011 (has links)
In the first part of my thesis, I was studying materials about using solar energy. Then I write search about all components that are necessary to be used in solar systems. After that I designed the structure of solar system used for heating the hot water for a family house about 4 persons. For this system I designed a regulator and one layer circuit board using Eagle layout editor 4.12r2, which I assembled and tested. This followed creating and debugging program for microprocessor that controls the whole device. This functional regulator for solar collectors connected in a box together with the necessary electronic components is my final product of this project.
53

Využití termovizních systémů v silnoproudé elektrotechnice / Utilization of thermal systems at power electrical engineering

Strnad, Karel January 2011 (has links)
The main theme of the master's thesis is using of thermal camera to measure temperatures in electrical engineering. First are mentioned the physical principles of heat transfer. Then the thesis deals with methods of determining the correct emissivity of the measured object and in the next point with sensors designed for sensing infrared radiation, there is also part dedicated to evaluation software Report Sat Standard, which was used to evaluate the pictures taken with thermal camera SAT-HY 6800. Next part of this work is the measurement of the DC and EC motor with help of thermocamera, which took place in the electric company ATAS Nachod. Attachment to this master's thesis there is animation of EC motor created in Autodesk Inventor.
54

Teplotní analýza elektrického stroje / Thermal analysis of electric machine

Ječmínek, Tomáš January 2013 (has links)
This masters thesis is focuse for measuring devices of temperature and their usability and accuraci in the event of asynchronous engine in operation. The values from meusuring of engine are used for preparing optimalization of construction. The right proposal of construction is check in numerical program and the results are validation.
55

Řídící jednotka zahradního bazénu / Control unit for garden pool

Jansa, Josef January 2014 (has links)
This work deals with the regulation of the water temperature in a small garden pool. The practical part consists of practical design control unit garden pool which is based on knowledge of the ambient air temperature and the temperature of the solar panel, evaluates and controls the filtration pump bypass valve and solar panel. Temperature sensing is done using digital sensors DS18B20 more 1-Wire bus. The control unit is formed by 2x4 matrix keyboard keys. All data are displayed on the alphanumeric display 2x16 characters. Control element is a microcontroller Atmel ATmega 3250PA. Furthermore, discussed in this thesis is data transfer using Bluetooth module.
56

Měření teploty pneumatik za jízdy vozidla s využitím infračer. pyrometrů OS100 / Tyre Temper. Meauserement on Moving Vehicle with Use of Infrared Pyromether OS100

Morávek, David January 2008 (has links)
Bc. David Morávek Tyre temperature measurement on moving vehicle with of infrared pyrometer OS100 MT, IAE, 2008, page 70, picture 41 Problemacy of recording the temperature and tyre pressure on driven car is processed in this diploma work. Suitable measuring chain was set up. Censor holders for this type of measurement were designed and produced. Driving exams and tests are depicted in this work, too. We came to the conclusion that tyre temperature depends on lengthways and transverse acceleration of the car and also on it’s load.
57

EquumTemp : A palpation aid that document and detect temperature changes on the surface of horse’s forelimbs / EquumTemp : Ett palperings hjälpmedel som dokumenterar temperatur förändringar av hästens framben

Andersson, Lisa January 2016 (has links)
At the moment, in the daily health care for horses there is a lack of technical aids for private use. As a horse owner you need to physically palpate the horse’s limbs to detect signs of injury and lameness. It is difficult and the signs are usually vague and hard to distinguish. Technology and interaction design could be the solution to this problem. The related research this paper builds on are: clinical complementary diagnostic methods for lameness diagnosis, wearable health monitor systems for humans and smart textiles on horses. The question this paper tries to answer is: How to develop and design a prototype of a product that is an aid for horse owners to document and better understand changes in surface temperature of the horse’s fetlock? To answer this question a user-centered design process was used. A survey, expert domain interview, design and development of a prototype, two different user testings’ and a design workshop. The result is a prototype of a palpating aid called EquumTemp. It is used by the horse owner as a second opinion on the status of their horse fetlock temperature. EquumTemp measures, stores and documents surface temperature of the fetlock. The prototype was tested by the author for 2 weeks and by three different potential users. The knowledge gained from the project resulted in defined product requirements. / Just nu, i den dagliga vården för hästar finns det en brist på tekniska hjälpmedel för privat bruk. Som hästägare måste du fysiskt palpera hästens ben för att upptäcka tecken på skador och hälta. Det är svårt och tecknen är oftast vaga och svåra att urskilja. Teknik och interaktionsdesign kan vara lösningen på detta problem. Relaterad forskning som denna rapport bygger på är: kliniska diagnostiska metoder för att diagnostisera hälta, monitorsystem för att övervaka människors hälsa och smarta textilier på hästar. Frågan denna rapport försöker besvara är: Hur man utvecklar och designar en prototyp av en produkt som är ett hjälpmedel för hästägare att dokumentera och bättre förstå förändringar i yttemperatur av hästens kotled? För att besvara denna fråga användes en användarcentrerad designprocess. En användarundersökning, expert domän intervju, design och utveckling av en prototyp, två olika användartestningar och en designworkshop. Resultatet är en prototyp av ett palperingshjälpmedel som kallas EquumTemp. Den används av hästägaren för att mäta hästens hud temperatur runt kotan. EquumTemp mäter, lagrar och dokument yttemperaturen runt kotan. Prototypen testades av författaren i 2 veckor och av tre olika potentiella användare. Kunskapen från projektet resulterade i definierade produktkrav.
58

Development Of Polymer Derived Sialcn Ceramic And Its Applications For High-temperature Sensors

Shao, Gang 01 January 2013 (has links)
Polymer-derived ceramic (PDC) is the name for a class of materials synthesized by thermal decomposition of polymeric precursors which excellent thermomechanical properties, such as high thermal stability, high oxidation/corrosion resistance and high temperature multifunctionalities. Direct polymer-to-ceramic processing routes of PDCs allow easier fabrication into various components/devices with complex shapes/structures. Due to these unique properties, PDCs are considered as promising candidates for making high-temperature sensors for harsh environment applications, including high temperatures, high stress, corrosive species and/or radiation. The SiAlCN ceramics were synthesized using the liquid precursor of polysilazane (HTT1800) and aluminum-sec-tri-butoxide (ASB) as starting materials and dicumyl peroxide (DP) as thermal initiator. The as-received SiAlCN ceramics have very good thermal-mechanical properties and no detectable weight loss and large scale crystallization. Solid-state NMR indicates that SiAlCN ceramics have the SiN4, SiO4, SiCN3, and AlN5/AlN6 units. Raman spectra reveals that SiAlCN ceramics contain “free carbon” phase with two specific Raman peaks of “D” band and “G” band at 1350 cm1 and 1600 cm1 , respectively. The “free carbon” becomes more and more ordered with increasing the pyrolysis temperature. EPR results show that the defects in SiAlCN ceramics are carbon-related with a g-factor of 2.0016±0.0006. Meanwhile, the defect concentration decreases with increasing sintered temperature, which is consistent with the results obtained from Raman spectra. iv Electric and dielectric properties of SiAlCN ceramics were characterized. The D.C. conductivity of SiAlCN ceramics increases with increasing sintered temperature and the activation energy is about 5.1 eV which higher than that of SiCN ceramics due to the presence of oxygen. The temperature dependent conductivity indicates that the conducting mechanism is a semiconducting band-gap model and follows the Arrhenius equation with two different sections of activation energy of 0.57 eVand 0.23 eV, respectively. The temperature dependent conductivity makes SiAlCN ceramics suit able for high temperature sensor applications. The dielectric properties were carried out by the Agilent 4298A LRC meter. The results reveal an increase in both dielectric constant and loss with increasing temperature (both pyrolysis and tested). Dielectric loss is dominated by the increasing of conductivity of SiAlCN ceramics at high sintered temperatures. SiAlCN ceramic sensors were fabricated by using the micro-machining method. High temperature wire bonding issues were solved by the integrity embedded method (IEM). It’s found that the micro-machining method is a promising and cost-effective way to fabricate PDC high temperature sensors. Moreover IEM is a good method to solve the high temperature wire bonding problems with clear bonding interface between the SiAlCN sensor head and Pt wires. The Wheatstone bridge circuit is well designed by considering the resistance relationship between the matching resistor and the SiAlCN sensor resistor. It was found that the maximum sensitivity can be achieved when the resistance of matching resistor is equal to that of the SiAlCN v sensor. The as-received SiAlCN ceramic sensor was tested up to 600 C with the relative output voltage changing from -3.932 V to 1.153 V. The results indicate that the relationship between output voltage and test temperature is nonlinear. The tested sensor output voltage agrees well with the simulated results. The durability test was carried out at 510 C for more than two hours. It was found that the output voltage remained constant for the first 30 min and then decreased gradually afterward by 0.02, 0.04 and 0.07 V for 1, 1.5 and 2 hours.
59

High Performance RF Circuit Design: High Temperature, Ultra-Low Phase Noise, and Low Complexity

Lohrabi Pour, Fariborz 21 January 2022 (has links)
Advanced achievements in the area of RF circuit design led to a significant increase in availability of wireless communications in everyday life. However, the rapid growth in utilizing the RF equipment has brought several challenges in different aspects of RF circuit design. This has been motivating researchers to introduce solution to cope with these challenges and further improve the performance of the RF circuits. In this dissertation, we focus on the improvements in three aspects of the circuit design. High temperature and temperature compensated transmitter design, ultra-low phase noise signal generators, and compact and low complexity polar transmitter design. Increase in the ambient temperature can impact the performance of the entire communication system. However, the RF hardware is main part of the system that is under the impact of the temperature variations in which it can change the characteristics of the individual building blocks of the RF chain. Moreover, transistors are the main elements in the circuit whose performance variation must be consider when the design target is compensating the temperature effects. The influence of the temperature variation is studied on the transistors and the building blocks in order to find the most effective approaches to compensate these variations and stabilize the performance of the RF chain at temperatures up to 220 C. A temperature sensor is designed to sense these variations and adjust the characteristics of the circuit components (e.g. bias voltages), accordingly. Further, a new variable gain phase shifter (VGPS) architecture is introduced toward minimizing the temperature impact on its performance in a phased-array transmitter architecture. Finally, a power amplifier as the last stage in a transmitter chain is designed and the variation in its performance with temperature is compensated through the VGPS stage. The transmitter is prototyped to evaluate its performance in practice. Another contribution of this dissertation is to introduce a novel voltage-controlled oscillator (VCO) structure to reduce the phase noise level below state-of-the-art. The noise to phase noise mechanism in the introduced doubly tuned oscillator is studied using linear time-variant (LTV) theory to identify the dominant noise sources and either eliminate or suppress these noise sources by introducing effective mechanism such as impedance scaling. The designed VCO is fabricated and measurement results are carried out that justified the accuracy of the analyses and effectiveness of the introduced design approach. Lastly, we introduce a compact and simple polar transmitter architecture. This type of transmitters was firstly proposed to overcome the serious shortcomings in the IQ transmitters, such as IQ imbalance and carrier leakage. However, there is still several challenges in their design. We introduce a transmitter architecture that operates based on charge to phase translation mechanism in the oscillator. This leads to significantly reduction in the design complexity, die area, and power dissipation. Further, it eliminates a number of serious issues in the design such as sampling rate of the DACs. comprehensive post-layout simulations were also performed to evaluate its performance. / Doctor of Philosophy / To keep up with the ever-growing demand for exchanging information through a radio frequency (RF) wireless network, the specification of the communication hardware (i.e. transmitter and receiver) must be improved as the bottleneck of the system. This has been motivating engineers to introduce new and efficient approaches toward this goal. In this dissertation however, we study three aspects of the circuit design. First, variation in the ambient temperature can significantly degrade the performance of the communication system. Therefore, we study these variations on the performance of the transmitter at high temperature (i.e. above 200 C). Then, the temperature compensation approaches are introduced to minimize the impact of the temperature changes. The effectiveness of the introduced techniques are validated through measurements of the prototyped transmitter. Second, signal generators (i.e. oscillators) are the inseparable blocks of the transmitters. Phase noise is one of the most important specifications of the oscillators that can directly be translated to the quality and data rate of the communication. A new oscillator structure targeting ultra-low phase noise is introduced in the second part of this dissertation. The designed oscillator is fabricated and measured to evaluate its performance. Finally, a new polar transmitter architecture for low power applications is introduced. The transmitter offers design simplicity and compact size compared to other polar transmitter architectures while high performance.
60

A WEB-BASED TEMPERATURE MONITORING SYSTEM FOR THE COLLEGE OF ARTS AND LETTERS

Solorio, Rigoberto 01 March 2015 (has links)
In general, server rooms have restricted access requiring that staff possess access codes, keys, etc. Normally, only administrators are provided access to protect the physical hardware and the data stored in the servers. Servers also have firewalls to restrict outsiders from accessing them via the Internet. Servers also cost a lot of money. For this reason, server rooms also need to be protected against overheating. This will prolong the lifecycle of the units and can prevent data loss from hardware failure. The California State University San Bernardino (CSUSB), Specifically the College of Arts and Letters server room has faced power failures that affected the Air Conditioning Unit (AC) and as a result the room became overheated for a long time, causing hardware failure to server units. This is why this project is important for the College and needs to be implemented as soon as possible. The administrator’s old method of controlling server room temperature was by manually adjusting the temperature box inside of the server room. Now it can be controlled and monitored using remote access. The purpose of A Web-Based Temperature Monitoring System for the College of Arts and Letters proposed in this project is to allow users to monitor the server room temperature through a website by using any computer or mobile device that has Internet access. Also, this system notifies users when the room attains a critical temperature by sending an email/text to the server room administrator. A Web-Based Temperature Monitoring System for the College of Arts and Letters project is for the exclusive use of the College of Arts & Letters (CAL) server room. The administrator is the only person that can grant access to others by creating a proper account. For this project three prototypes will be implemented, first to measure the current server room temperature, the second to show the temperature history of the room, and third to use the built-in search system to locate times that given temperatures were attained.

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