Dissertations / Theses on the topic 'Wire-temperature'
To see the other types of publications on this topic, follow the link: Wire-temperature.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Wire-temperature.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Sitter, Nicholas James. "Two-wire, low component count soil temperature sensor." Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/1081.
Full textAbstract:
A two-wire, low component count soil temperature sensor was developed. The sensor uses one wire for ground and the other wire is used for both power and communication. Pulse width modulation is used to send temperature measurements to the master, where the duty cycle is proportional to the temperature. The sensor parasitically powers itself from the bidirectional data line. In order to reduce the number of components necessary, a microcontroller with an internal temperature sensor is used. Finally, the sensor can receive data from the master on the bidirectional communication line, which is used for calibrating the sensor.
2
Suman, Shivesh K. "Characterization of temperature variation during the wire bonding process." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/17560.
Full text
3
Medrano, Téllez Alexis G. "Fibre laser metal deposition with wire : parameters study and temperature control." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/12812/.
Full textAbstract:
This research addresses the development of a laser metal deposition process with wire feeding and melt pool temperature control. The system consists of a2 kW fibre laser, a CNC table, a wire feeder and a temperature monitoring and control system. A study of the influence of the main parameters on the process and on the deposited bead geometry was performed. The parameters analysed were: laser power, traverse speed and wire feed rate. As a result of this study, a process window was established for metal deposition of stainless steel 308LSi (wire) on stainless steel 304 (plate). The influence of the parameters on the bead geometry (height and width) was analysed applying the Design of Experiments methodology, using a full factorial design 3k. The results are presented, together with important practical considerations for laser metal deposition with wire. A closed-loop temperature control system was developed: it controls the melt pool temperature by means of modifying the laser power. The melt pool temperature was measured by a two-colour pyrometer, whereas a single-colour pyrometer was used for monitoring the workpiece (upper layer) temperature. A model of the melt pool was derived from a heat balance equation. It was then utilized for the design of the controller in the discrete domain, using the root locus method. The control algorithm was developed in LabVIEW software and executed in a computer. The control system was implemented successfully and was utilized to build single-bead walls and cylinders of stainless steel 308LSi. The study performed on the parameters and the developed temperature controller proved to be very effective tools to facilitate the transition to the deposition of titanium alloy Ti-6A1-4V, requiring only minimum adaptations. Single-bead walls and cylinders were also built in this material. Stable and smooth metal deposition was achieved for both materials. During the experiments, several strategies for the automation of wire metal deposition of multilayered structures were developed. Finally, mechanical tests were performed. The mechanical properties of the deposited materials are comparable to those in wrought (annealed) condition and to similar alloys made by laser powder deposition systems. The system developed in this work provides a means to perform stable and smooth wire metal deposition, achieving good mechanical properties. It also facilitates the transition to deposit different materials. It has a flexible structure and can be expanded or adapted to be used in other wire metal deposition systems.
4
Chan, Yu Hin. "Optimization of metallization and process variables in low temperature wire bonding technology /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MECH%202003%20CHAN.
Full textAbstract:
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 129-132). Also available in electronic version. Access restricted to campus users.
5
D'AMICO, ANTONIO. "INNOVATIVE ANALOG AND MIXED-SIGNAL SOLUTIONS FOR PRECISE MEASUREMENT OF ELECTRICAL QUANTITIES IN POWER TRANSISTORS." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/198966.
Full textAbstract:
Questa tesi presenta lo sviluppo di un sistema multifunzionale a segnali misti per applicazioni automobilistiche e, in particolare, per misure di corrente high-side, rilevamento di distacco dei carichi e protezione da sollecitazioni termoelettriche.
Il sistema è composto di un ADC a inseguimento con diversa risoluzione (meno fine, fine e finissima) in tre intervalli per adattarsi ai requisiti di sistema e ottimizzare il design in termini di area.
La risoluzione meno fine, usata per l’intero intervallo di valori d’ingresso di corrente [0A: 100A], ha fornisce 5 b e viene utilizzata per la funzione di rilevamento dello stress. Le risoluzioni fine e finissima sono utilizzate per i valori di corrente d’ingresso più bassi [0A: 14A] dove è richiesta una maggiore precisione della misura.
Inoltre, il sistema implementa due funzionalità di protezione: è in grado di rilevare un eventuale distacco del carico elaborando le misure di corrente ed è in grado di stimare la temperatura del filo elaborando digitalmente l'uscita ADC e di segnalare se i cavi si riscaldano pericolosamente.
Il monitoraggio della corrente e la funzione di protezione sono molto importanti poiché un sistema affidabile e integrato consente alle case automobilistiche di progettare il cablaggio dei veicoli in modo più efficiente, riducendo il diametro dei cavi in rame, e quindi di risparmiare sui costi.This thesis presents the development of a mixed-signal multi-functional system for automotive applications and, in particular, for high-side current measurements, open-load detection and thermo-electrical stress protection. The system is composed of a tracking ADC featuring a triple-ranged resolution (coarse, fine and finest) in order to adapt to the system requirements and optimize the design in terms of area. The coarse range, designed for the full-scale input values [0A:100A], has a 5 b resolution and it is used for the stress detection feature. The fine and the finest ranges are used for lowest input current values [0A:14A] where more accuracy is required. Moreover, the system implements two protections functionalities: it is capable to detect a possible load detachment by processing the current measurements and it is able to estimate the wire temperature by digitally processing the ADC output and to signal if the cables heat up dangerously. The current monitoring and the protection feature are extremely important as a reliable and embedded system enables the car manufactures to design the vehicles harness more efficiently, by reducing the copper cables diameter, and therefore to save costs
6
Malizia, Fabio. "A numerical study of temperature effects on hot wire measurements inside turbulent channel flows." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5221/.
Full textAbstract:
A way to investigate turbulence is through experiments where hot wire measurements are performed. Analysis of the in turbulence of a temperature gradient on hot wire measurements is the aim of this thesis work. Actually - to author's knowledge - this investigation is the first attempt to document, understand and ultimately correct the effect of temperature gradients on turbulence statistics.
However a numerical approach is used since instantaneous temperature and streamwise velocity fields are required to evaluate this effect. A channel flow simulation at Re_tau = 180 is analyzed to make a first evaluation of the amount of error introduced by temperature gradient inside the domain. Hot wire data field is obtained processing the numerical
flow field through the application of a proper version of the King's law, which connect voltage, velocity and temperature.
A drift in mean streamwise velocity profile and rms is
observed when temperature correction is performed by means of centerline temperature. A correct mean velocity pro�le is achieved correcting temperature through its mean value at each wall normal position, but a not negligible error is still present into rms. The key point to correct properly the sensed velocity from the hot wire is the knowledge of the instantaneous temperature field. For this purpose
three correction methods are proposed.
At the end a numerical simulation at Re_tau =590 is also evaluated in order to confirm the results discussed earlier.
7
Koujili, Mohamed. "Design and construction of a new actuator for the LHC wire scanner." Thesis, Belfort-Montbéliard, 2013. http://www.theses.fr/2013BELF0196/document.
Full textAbstract:
Le LHC met en collision deux faisceaux de protons avec une énergie de 7 Tevchacun, entrainant ainsi un taux de particules d'environ 109 Hz. Le taux departicules est déterminé la production d'une coupe transversale, une constancenaturelle, la luminosité et un paramétre dépendant de l'accélérateurcapable de décrire les faisceaux de particules. La luminosité dépend dunombre de particules dans chaque faisceau linéairement et des dimensionstransversales du faisceau inversement. Elle augmente avec la densité dufaisceau de particules et en conséquence, la probabilité d'interactions estaccrue. Pour optimiser les tailles des faisceaux transversaux, on utilisedes dispositifs de contrle de pro_le, qui permettent de mesurer les changementsde paramétres dépendants. A l'intérieur du LHC, trois di_érentstypes de dispositifs de contrle des pro_les sont installés, savoir le WireScanner (WS), le Synchroton Light Monitor et le Rest Gas Pro_le Monitor.Le WS est considéré comme étant le plus précis de ces trois dispositifsde contrle et sert d'appareil de calibrage pour les deux autres. Ils'agit d'un appareil électromécanique qui mesure l'état de densité du faisceautransversale de faon intermittente. Lorsque le cble traverse le faisceau,l'interaction particule-matiére génére une cascade de particules secondaires.Ces derniers sont interceptés par un scintillateur, lequel est attaché un photo-multiplieur, et ce a_n de mesurer l'intensité de la lumiéreainsi produite. L'amplitude du signal lumineux est proportionnelle la densité de la portion de faisceau interceptée. L'acquisition de la position du_l et celle de l'intensité du signal sont synchronisées avec la fréquence dela révolution de particules puis sont combinées pour construire le pro_lede densité du faisceau transversal. Le WS est installé et mis en marchedans tous les accélérateurs circulaires du CERN sur une base réguliéreThe LHC collides two protons beams with an energy of 7 TeV each resultingin a aimed total particle rate of about 109 Hz. The particle rateis determined by the production cross section, a natural constant and theluminosity accelerator dependent parameter describing the particle beams.The luminosity depends on the number of particles in each beam linearlyand on the transverse dimensions of the particle beam inversely. It increaseswith the particle beam density and therefore the probability of interactions.To optimize the transverse beams sizes, pro_le monitors are used to measureparameter depending changes. Within the LHC, three di_erent typesof pro_le monitors are installed: Wire scanner (WS), Synchrotron lightmonitor and Rest Gas Pro_le Monitor. The WS monitor is considered tobe the most accurate of these monitors and serves as a calibration devicefor the two others. The WS is an electro-mechanical device which measuresthe transverse beam density pro_le in an intermittent way. As the wirepasses through the beam, the particle-matter interaction generates a cascadeof secondary particles. These are intercepted by a scintillator, which isattached to a photomultiplier in order to measure the intensity of the lightthereby produced. The light signal amplitude is proportional to the densityof the intercepted beam portion. The acquisitions of the wire position andthe intensity signal are synchronized with the particle revolution frequencyand are combined to construct the transverse beam density pro_le. TheWS is installed and operated in all circular accelerators of CERN on a dailybasis
8
Vičar, Pavel. "Měření teploty ve fotovoltaických systémech." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218702.
Full textAbstract:
This diploma thesis deals with covers design and realisation of device for multipoint temperature measuring in fotovoltaic systems. As a controlling microcomputer is used Atmel ATMega128L, temperature sensors are realised by DS18S20 digital thermometers, connected via 1-wire bus. System can read temperature from x temperature sensors, includes memory for measured data, real time clock and display with buttons for basic user control. Temperatures are measured periodically, values are stored into internal memory and showed on display.Measured data can also be transferred via seriál bus to clinent PC. Device is projected as a battery-operated compact tool. The final realization is made with respect to minimal system requirements and to possible future extensibility for wider usage spectrum.
9
Knott, Ryan Christopher. "High temperature durability of metals for use in a particle heating receiver for concentrated solar power." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53117.
Full textAbstract:
An experimental investigation is presented on a novel High Temperature Falling Particle Receiver for Concentrated Solar Power (CSP) to quantify the extent of erosion of the receiver structural materials by the flowing particulate matter. The current receiver design uses a series of metal wire mesh screens to slow down the particulate flow through the receiver in order to increase their residence time thereby achieving the desired temperature rise within the receiver without the need for particulate recirculation. The solid particulates are gravity fed through the receiver where they absorb the incident thermal energy before flowing to a high temperature storage bin upstream of a heat exchanger where the heat stored in the particulate material is transferred to the working fluid for the power cycle. To assess the effective life of the receiver, this experimental investigation is undertaken. This thesis includes the development of an apparatus to test wire meshes under high temperature and particle abrasion conditions, and the presentation and analysis of these results.
10
Bosworth, Kyle Judson. "Health Monitoring of the Veterans' Glass City Skyway: Vibrating Wire Strain Gage Testing, Study of Temperature Gradients and a Baseline Truck Test." Connect to Online Resource-OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1197693985.
Full textAbstract:
Thesis (M.S.)--University of Toledo, 2007.Typescript. "Submitted as partial fulfillment of the requirements for the Master of Science in Civil Engineering." "A thesis entitled"--at head of title. Bibliography: leaves 86-87.
11
Loh, Wei Sun. "Studies of Avalanche Breakdown Characteristics in 4H-SiC and reliability of pure aluminium wire bonds for high power and high temperature applications." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500188.
Full text
12
Kandil, Mohamed E. "The development of a vibrating wire viscometer and a microwave cavity resonator for the measurement of viscosity, dew points, density, and liquid volume fraction at high temperature and pressure." Thesis, University of Canterbury. Chemical and Process Engineering, 2005. http://hdl.handle.net/10092/1070.
Full textAbstract:
This thesis describes the development and testing of two apparatuses; a vibrating wire viscometer to measure the viscosity of fluids over a wide range of temperature and pressure; and a microwave cavity resonator to measure dew points, gas phase densities, and liquid drop out volumes. Viscosity and density of downhole fluids are very important properties as their values can determine the economic viability of a petroleum reservoir. A vibrating wire viscometer has been developed with an electrically insulating tensioning mechanism. It has been used with two wires, of diameters (0.05 and 0.150) mm, to measure the viscosity of methylbenzene and two reference fluids with viscosities of (10 and 100) mPa·s at T = 298 K and p = 0.1 MPa, at temperatures in the range (298 to 373) K and pressures up to 40 MPa, where the viscosity covers the range (0.3 to 100) mPa·s, with a standard uncertainty < 0.6 %. The results differ from literature values by < ±1 %. The results demonstrate that increasing the wire diameter increases the upper operating viscosity range of the vibrating wire viscometer, a result anticipated from the working equations. For the microwave cavity resonator, the method is based on the measurements of the resonance frequency of the lowest order inductive-capacitance mode. The apparatus is capable of operating at temperatures up to 473 K and pressures below 20 MPa. This instrument has been used to measure the dew pressures of {0.4026CH4 + 0.5974C3H8} at a temperature range from 315 K up to the cricondentherm ˜ 340 K. The measured dew pressures differ by less than 0.5 % from values obtained by interpolation of those reported in the literature, which were determined from measurements with experimental techniques that have quite different potential sources of systematic error than the radio-frequency resonator used here. Dew pressures estimated from both NIST 14 and the Peng-Robinson equation of state lie within < ±1 % of the present results at temperature between (315 and 337) K while predictions obtained from the Soave-Redlich-Kwong cubic equation of state deviate from our results by 0.4 % at T = 315 K and these differences increase smoothly with increasing temperature to be -2.4 % at T = 337 K. Densities derived from dielectric permittivity measurements in the gas phase lie within < 0.6 % of the values calculated from the Soave-Redlich-Kwong cubic equation of state and about 1 % from values obtained with the Harvey and Prausnitz correlation based on a mixture reduced density. The calculations with Kiselev and Ely parametric crossover equation of state (based on Patel-Teja EOS) gave deviations < 0.7 %. Liquid volume fractions, in the 2-phase region, were measured from (0.5 to 7) cm3 in a total volume of about 50 cm3 at different isochors. The measured liquid volume fractions differ from values obtained with the Soave-Redlich-Kwong cubic equation of state by between 0 and 3 % at T < 326 K and about 8 % on approach to the critical region. The large deviations observed in the critical region were anticipated because of the known poor performance of the cubic equations of state with regard to the calculation of the liquid density in the vicinity of the critical temperature.
13
Oliphant, Clive Justin. "Filament carburization during the hot-wire chemical vapour deposition of carbon nanotubes." Thesis, University of the Western Cape, 2008. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7060_1263948958.
Full text
14
Zhou, En. "The use of FLUENT for heat flow studies of the hot-wire chemical vapor deposition system to determine the temperatures reached at the growing layer surface." Thesis, University of the Western Cape, 2009. http://hdl.handle.net/11394/1705.
Full textAbstract:
Magister Scientiae - MScThe overall aim of this project is to study the heat transfer inside the reaction chamber of the Hot-Wire Chemical Vapor Deposition (HWCVD) system with a commercial software package FLUENT6.3; it is one of the most popular Computational Fluid Dynamics solvers for complex flows ranging from incompressible to mildly compressible to even highly compressible flows. The wealth of physical models in FLUENT allows us to accurately predict laminar and turbulent flows, various modes of heat transfer, chemical reactions, multiphase flows and other phenomena with complete mesh flexibility and solution-based mesh adaptation. In this study the 3-D HWCVD geometry was measured and created in GAMBIT which then generates a mesh model of the reaction chamber for the calculation in FLUENT. The gas flow in this study was characterized as the steady and incompressible fluid flow due to the small Mach number and assumptions made to simplify the complexity of the physical geometry. This thesis illustrates the setups and solutions of the 3-D geometry and the chemically reacting laminar and turbulent gas flow, wall surface reaction and heat transfer in the HWCVD deposition chamber.
South Africa
15
Husain, Muhammad Dawood. "Development of temperature sensing fabric." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/development-of-temperature-sensing-fabric(0e5e8367-c3b2-4cff-bcc9-f32fac97b50f).html.
Full textAbstract:
Human body temperature is an important indicator of physical performance and condition in terms of comfort, heat or cold stress. The aim of this research was to develop Temperature Sensing Fabric (TSF) for continuous temperature measurement in healthcare applications. The study covers the development and manufacture of TSF by embedding fine metallic wire into the structure of textile material using a commercial computerised knitting machine. The operational principle of TSF is based on the inherent propensity of a metal wire to respond to changes in temperature with variation in its electrical resistance. Over 60 TSF samples were developed with combinations of different sensing elements, two inlay densities and highly textured polyester yarn as the base material. TSF samples were created using either bare or insulated wires with a range of diameters from 50 to 150 μm and metal wires of nickel, copper, tungsten, and nickel coated copper. In order to investigate the Temperature-Resistance (T-R) relationship of TSF samples for calibration purposes, a customised test rig was developed and monitoring software was created in the LabVIEW environment, to record the temperature and resistance signals simultaneously. TSF samples were tested in various thermal environments, under laboratory conditions and in practical wear trials, to analyse the relationship between the temperature and resistance of the sensing fabric and to develop base line specifications such as sensitivity, resistance ratio, precision, nominal resistance, and response time; the influence of external parameters such as humidity and strain were also monitored. The regression uncertainty was found to be less than in ±0.1°C; the repeatability uncertainty was found to be less than ±0.5°C; the manufacturing uncertainty in terms of nominal resistance was found to be ± 2% from its mean. The experimental T-R relationship of TSF was validated by modelling in the thermo-electrical domain in both steady and transient states. A maximum error of 0.2°C was found between the experimental and modelled T-R relationships. TSF samples made with bare wire sensing elements showed slight variations in their resistance during strain tests, however, samples made with insulated sensing elements did not demonstrate any detectable strain-dependent-resistance error. The overall thermal response of TSF was found to be affected by basal fabric thickness and mass; the effect of RH was not found to be significant. TSF samples with higher-resistance sensing elements performed better than lower-resistance types. Furthermore, TSF samples made using insulated wire were more straightforward to manufacture because of their increased tensile strength and exhibited better sensing performance than samples made with bare wire. In all the human body wear trials, under steady-state and dynamic conditions both sensors followed the same trends and exhibited similar movement artifacts. When layers of clothing were worn over the sensors, the difference between the response of the TSF and a high-precision reference temperature were reduced by the improved isothermal conditions near the measurement site.
16
Martínek, Jaroslav. "Modul pro monitorování teploty." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217539.
Full textAbstract:
Content of the Bachelor Thesis covers design and realisation of an unit for multipoint temperature measuring in cooling and freezing equipments in food stores and shops. As a controlling microcomputer is used an Atmel ATMega128, temperature sensors are realised by DS18S20 digital thermometers, connected via 1-wire bus. Unit can read temperature from 32 temperature sensors, includes memory for measured data, real time clock, Ethernet interface and display with buttons for basic user control. Temperatures are measured periodically with user defined interval, values are stored into internal memory and showed on display. Measured data can also be transferred via Ethernet to clinent PC, where can be viewed in form of table and graphs.
17
Cozonac, Dorin. "Conception d'une machine asynchrone haute température." Thesis, Artois, 2015. http://www.theses.fr/2015ARTO0209/document.
Full textAbstract:
Les bobinages des machines électriques tournantes actuelles sont, pour la plupart, isolés avec des matériaux issus de la chimie organique. La limite en température des bobinages actuels se situe au-dessous de 240°C. L’augmentation significative de la température de fonctionnement d’une machine permettrait d’envisager, indirectement, une augmentation de la densité de courant dans les conducteurs actifs. Dans ces conditions, ces nouvelles machines peuvent présenter une puissance, tant massique que volumétrique, supérieures à celles exploitées actuellement. De plus, les matériaux magnétiques permettent vraisemblablement de fonctionner jusqu’à 800°C. La limite technologique actuelle pour les machines est clairement l’isolant des conducteurs électriques. Ce sujet de thèse propose de définir une approche théorique couplée à des validations expérimentales pour définir les matériaux les mieux adaptés aux machines hautes températures en termes de mise en œuvre et de performances électriques. La conception, repensée autour du bobinage, sera concrétisée par le calcul d’une machine asynchrone à haute température (400°C au cœur du bobinage). Le bobinage devra être placé au cœur de la démarche de conception des machines en adaptant les formes et les propriétés des circuits magnétiques aux caractéristiques des nouvelles bobinesThe windings that are currently used in electrical machines are mostly insulated based on organic insulation. The temperature limit of these windings is up to 240°C. Increasing the working temperature of electrical motors means, indirectly the increasing of current density on the main conductors. Therefore these new motors may provide a higher mass and volume power as classical machines. Furthermore, the magnetic materials can work up to 800 °C. Indeed, in reality technical limit today is the wire insulation. The objective of thesis is to define a theoretical approach combined with experimental validations for identify the appropriate electrical materials used on high-temperature electrical machines. Design is fixed around the winding, that will implemented by calculating a high-temperature asynchronous machine (400°C of windings). The windings are placed as the base of machine design and will determine the geometrical shape and properties of magnetic core
18
Chen, Zheng. "Electrical Integration of SiC Power Devices for High-Power-Density Applications." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23923.
Full textAbstract:
The trend of electrification in transportation applications has led to the fast development of high-power-density power electronics converters. High-switching-frequency and high-temperature operations are the two key factors towards this target. Both requirements, however, are challenging the fundamental limit of silicon (Si) based devices. The emerging wide-bandgap, silicon carbide (SiC) power devices have become the promising solution to meet these requirements. With these advanced devices, the technology barrier has now moved to the compatible integration technology that can make the best of device capabilities in high-power-density converters. Many challenges are present, and some of the most important issues are explored in this dissertation.
First of all, the high-temperature performances of the commercial SiC MOSFET are evaluated extensively up to 200 degree C. The static and switching characterizations show that the device has superior electrical performances under elevated temperatures. Meanwhile, the gate oxide stability of the device - a known issue to SiC MOSFETs in general - is also evaluated through both high-temperature gate biasing and gate switching tests. Device degradations are observed from these tests, and a design trade-off between the performance and reliability of the SiC MOSFET is concluded.
To understand the interactions between devices and circuit parasitics, an experimental parametric study is performed to investigate the influences of stray inductances on the MOSFETs switching waveforms. A small-signal model is then developed to explain the parasitic ringing in the frequency domain. From this angle, the ringing mechanism can be understood more easily and deeply. With the use of this model, the effects of DC decoupling capacitors in suppressing the ringing can be further explained in a more straightforward way than the traditional time-domain analysis. A rule of thumb regarding the capacitance selection is also derived.
A Power Electronics Building Block (PEBB) module is then developed with discrete SiC MOSFETs. Integrating the power stage together with the peripheral functions such as gate drive and protection, the PEBB concept allows the converter to be built quickly and reliably by simply connecting several PEBB modules. The high-speed gate drive and power stage layout designs are presented to enable fast and safe switching of the SiC MOSFET. Based on the PEBB platform, the state-of-the-art Si and SiC power MOSFETs are also compared in the device characteristics, temperature influences, and loss distributions in a high-frequency converter, so that special design considerations can be concluded for the SiC MOSFET.
Towards high-temperature, high-frequency and high-power operations, integrated wire-bond phase-leg modules are also developed with SiC MOSFET bare dice. High-temperature packaging materials are carefully selected based on an extensive literature survey. The design considerations of improved substrate layout, laminated bus bars, and embedded decoupling capacitors are all discussed in detail, and are verified through a modeling and simulation approach in the design stage. The 200 degree C, 100 kHz continuous operation is demonstrated on the fabricated module. Through the comparison with a commercial SiC phase-leg module designed in the traditional way, it is also shown that the design considerations proposed in this work allow the SiC devices in the wire-bond structure to be switched twice as fast with only one-third of the parasitic ringing.
To further push the performance of SiC power modules, a novel hybrid packaging technology is developed which combines the small parasitics and footprint of a planar module with the easy fabrication of a wire-bond module. The original concept is demonstrated on a high-temperature rectifier module with SiC JFET. A modified structure is then proposed to further improve design flexibility and simplify module fabrication. The SiC MOSFET phase-leg module built in this structure successfully reaches the switching speed limit of the device almost without any parasitic ringing.
Finally, a new switching loop snubber circuit is proposed to damp the parasitic ringing through magnetic coupling without affecting either conduction or switching losses of the device. The concept is analyzed theoretically and verified experimentally. The initial integration of such a circuit into the power module is presented, and possible improvements are proposed.Ph. D.
19
Silva, Gleison Elias da. "Desenvolvimento de transdutor em fibra óptica com estrutura híbrida LPG-FBG para medição de propriedades térmicas de materiais." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-27022018-102025/.
Full textAbstract:
Este trabalho apresenta o estudo, a implementação e a caracterização de transdutores compostos por uma estrutura formada por grades de Bragg (FBG, Fiber Bragg Gratings) e grades de período longo (LPG, Long Period Gratings) em fibra óptica com cobertura metálica autoaquecida para medição da condutividade térmica e da difusividade térmica de materiais baseado no método do fio quente (HWM, Hot-Wire Method) convencional. O autoaquecimento da fibra óptica do dispositivo desenvolvido neste trabalho é provocado pela luz de espectro infravermelho injetada por um laser de bombeamento, que é espalhada por uma LPG e absorvida por um filme fino metálico depositado na superfície da fibra. Os transdutores apresentados são compactos, simples, robustos e imunes a interferências eletromagnéticas. O arranjo experimental utilizando o dispositivo híbrido LPG-FBG foi capaz de medir as condutividades térmicas do ar atmosférico e da água comum com precisões de 27% e 14%, respectivamente. Foram identificados vários fatores que afetam a precisão e a exatidão das medidas realizadas, sendo propostas diversas formas de correções de modo a melhorar o desempenho do arranjo. Foi demonstrada com sucesso a viabilidade da aplicação original do arranjo experimental utilizando o dispositivo híbrido LPG-FBG em fibra óptica autoaquecida para a medição de propriedades térmicas de fluidos (ar e água).This work presents the study, implementation, and characterization of transducers composed of a structure formed by Fiber Bragg Gratings (FBG) and Long Period Gratings (LPG) in optical fiber with self-heating coverage for measurement of thermal conductivity and thermal diffusivity of materials based on the Hot-Wire Method (HWM). The self-heating fiber optic device developed in this work is caused by the light of infrared spectrum injected by a pumping laser, which is spread by an LPG and absorbed by a thin metallic film deposited on the surface of the fiber. The transducers are compact, simple, robust and immune to electromagnetic interference. The experimental arrangement using the optical fiber sensor based on LPG-FBG hybrid structure was able to measure the thermal conductivity of atmospheric air and water with accuracies of 27% and 14%, respectively. Several factors were identified that affect the precision and the accuracy of the measures carried out, whereby various forms of corrections are being proposed to improve overall performance. The viability of the original application of the experimental arrangement using the LPG-FBG hybrid device in self-heating optical fiber for the measurement of thermal properties of fluids (air and water) has been successfully demonstrated.
20
Kirner, Stefan [Verfasser], Jochen [Akademischer Betreuer] Schein, Jochen [Gutachter] Schein, and Thomas [Gutachter] Klassen. "Tomographic Two-Color-Pyrometry of the Wire Arc Spray Process regarding Particle Temperature and in-flight Particle Oxidation / Stefan Kirner ; Gutachter: Jochen Schein, Thomas Klassen ; Akademischer Betreuer: Jochen Schein ; Universität der Bundeswehr München, Fakultät für Elektrotechnik und Informationstechnik." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2018. http://d-nb.info/1175916986/34.
Full text
21
Kirner, Stefan Verfasser], Jochen [Akademischer Betreuer] [Schein, Jochen Gutachter] Schein, and Thomas [Gutachter] [Klassen. "Tomographic Two-Color-Pyrometry of the Wire Arc Spray Process regarding Particle Temperature and in-flight Particle Oxidation / Stefan Kirner ; Gutachter: Jochen Schein, Thomas Klassen ; Akademischer Betreuer: Jochen Schein ; Universität der Bundeswehr München, Fakultät für Elektrotechnik und Informationstechnik." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2018. http://d-nb.info/1175916986/34.
Full text
22
Yang, Yuan. "Influence of Chemical Doping on Microstructures and Superconducting Properties of MgB2 Wires and Bulk Samples." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469187563.
Full text
23
Tříska, Vít. "Univerzální řídicí jednotka solárních kolektorů." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2010. http://www.nusl.cz/ntk/nusl-237100.
Full textAbstract:
This thesis deals with design and implementation of a versatile control unit, which is primarily designed for control of solar collectors. It describes the various stages of design. First, the system of solar collectors is introduced. Its input-output parts are analyzed and the requirements are determined for the control unit. The characteristics of temperature sensors are examined, the work deals with continuous variable speed circulators. The following part is dedicated to hardware and software implementation of the objectives of the work. The boards were designed in Eagle design environment, the firmware was written in C programming language. In conclusion, the evaluation of the results of the proposed system and possible ways of its further development are discussed. The versatile control unit can be deployed in practice realistically.
24
Saez, Manuel. "Contribution à l'étude expérimentale de la convection mixte." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10197.
Full textAbstract:
Les travaux presentes dans cette these concernent plusieurs aspects d'un programme experimental dont l'objectif est de fournir des donnees pour la validation et l'aide au developpement des modeles de turbulence dans les codes de calculs thermohydrauliques, pour des situations d'etudes allant de la convection forcee a la convection naturelle (nombre de reynolds : 10#3 a 6. 10#4 et nombre de richardson : 10#-#4 a 1). La configuration etudiee est celle d'un ecoulement ascendant d'air entre deux parois verticales a temperatures differentes. Dans le premier chapitre, nous avons extrait de la bibliographie les donnees disponibles pour les ecoulements en canal plan et en couches limites. Le second chapitre presente les caracteristiques de l'installation et du banc d'etalonnage ainsi que la methode de positionnement des sondes pour atteindre la precision de l'ordre du centieme de millimetre requise en paroi. Le troisieme chapitre presente les techniques de mesure mises en uvre ainsi que les developpements apportes a certaines techniques experimentales. Les lois classiques de refroidissement d'un fil chaud sont verifiees jusqu'a des vitesses de quelques centimetres par seconde. En prealable aux resultats de convection forcee et mixte, nous presentons une methode que nous avons developpee pour permettre la realisation de mesures tres proches de la paroi. Notre procedure de correction des mesures est elaboree grace a une evaluation numerique de l'erreur basee sur une modelisation thermohydraulique. Les mesures en convection forcee ont permis de retrouver les lois de paroi. En convection mixte, les profils moyens de vitesse et de temperature, obtenus avec une sonde a fil chaud simple, montrent nettement l'effet des forces de volume sur le champ de vitesses. Concernant les lois de paroi en convection mixte, une piste proposee consiste a trouver des lois algebriques qui prennent en compte les effets des forces de volume, a partir de la base de donnees issue de notre experience en convection mixte. La recherche de l'existence de lois de paroi en situation de convection mixte montre que les representations des profils dimensionnels de vitesse et de temperature moyenne peut se faire suivant des lois du meme type que celles de convection forcee avec des constantes d'integration qui sont des fonctions lineaires du nombre de richardson.
25
Sordes, Delphine. "Imagerie, manipulation et contact électronique atome par atome sur la surface Si(100) : H avec le microscope à effet tunnel basse température à 4 pointes." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30048/document.
Full textAbstract:
La construction de circuits électroniques de section atomique est l'un des grands défis de la nanoélectronique ultime. Pour construire un circuit électronique atomique, il faut d'abord mettre au point l'instrument de construction puis choisir la surface-support stabilisant ce circuit. Sur la surface d'Au(111) préparée en ultra vide, nous avons mis en œuvre et stabilisé le tout premier LT-UHV-4 STM. Ce microscope à 4 pointes STM balayant en même temps et indépendamment une même surface a été construit pour le CEMES par la société ScientaOmicron. Sur l'Au(111), nous avons reproduit tous les résultats expérimentaux obtenus sur les meilleurs LT-UHV-STM à une pointe comme la précision en rugosité de 2 pm, les caractéristiques I-V sans moyenne sur un seul atome pendant plusieurs dizaines de minutes et la manipulation atomique suivant les modes de tiré, glissé et poussé d'un seul atome d'or sur la surface. Une fois cette optimisation réalisée, nous avons appliqué notre LT-UHV-4 STM à la surface de Si(100):H, support probable des futurs circuits atomiques électroniques. Le choix de ce support est discuté en détail avant l'enregistrement et l'analyse des images STM. Les échantillons utilisés proviennent, soit du procédé semi-industriel pleine-plaque de silicium mis au point au CEA-LETI, soit de leur préparation in situ se déroulant directement dans la chambre de préparation du LT-UHV-4 STM. Nous avons pris soin de bien interpréter les images STM de la surface Si(100):H afin par exemple de déterminer la position de chaque atome d'hydrogène. La lithographie atomique par STM a été exploitée, par pointe, sur le LT-UHV-4 STM, en mode manipulation verticale atome-par-atome et mode balayage plus rapide mais rendant l'écriture atomique moins précise. Nous avons construit nos propres fils atomiques puis des plots de contact atomiques, petits carrés de Si(100)H dépassivés de quelques nm de côté. Les courants de fuite à 2 pointes et à l'échelle atomique ont ainsi pu être mesurés sur la surface de Si(100):H entre deux de ces plots. Pour préparer les contacts atomiques à au moins 2 pointes sur un fil atomique ou sur des plots de contact nanométrique, nous avons étudié en détail les différents types de contact pointe STM-liaison pendante unique montrant la difficulté d'atteindre un quantum de conductance au contact, de par un effet de courbure de bandes. Il est donc difficile sans une mesure de force complémentaire de déterminer en partant du contact tunnel les différentes étapes du contact mécanique, électronique au contact chimique. Nos résultats ouvrent la voie à la caractérisation des circuits électroniques construits atome par atome et à l'échelle atomique à la surface d'un semi-conducteurThe construction of electronic circuits of atomic section is one of the great challenges of the ultimate nanoelectronics. To build an atomic electronic circuit, it is necessary first to develop the dedicated instrument to build up and then to choose the support surface stabilizing this circuit. On the Au(111) surface prepared in ultra-vacuum, we implemented and stabilized the very first LT-UHV-4 STM. This STM 4-probes microscopes scanning at the same time and independently the same surface was built for the CEMES by the ScientaOmicron company. On Au(111), we reproduced all the experimental results obtained on the best LT-UHV-STM with one probe such as the precision in roughness of 2 pm, the IV characteristics recording without any average on a single atom for several tens of minutes and the atomic manipulation following the pulling, sliding and pushing modes of a single gold atom on the surface. Once this optimization was carried out, we applied our LT-UHV-4 STM to the surface of Si(100):H, probable support of the future electronic atomic circuits. The choice of this medium is discussed in detail before recording and analysis of the STM images. The samples used come either from the semi-industrial full-wafer silicon process developed at CEA-LETI or from their in-situ preparation, which takes place directly in the preparation chamber of the LT-UHV-4 STM. We have taken care to interpret the STM images of the surface Si(100):H in order to locate the position of each hydrogen atom. The atomic lithography by STM has been exploited, by using one tip from our LT-UHV-4 STM, by atom-per-atom vertical mode and faster scanning mode. The last makes atomic writing less accurate. We have constructed our own atomic wires and then atomic contact pads, small squares of Si(100)H defeated by a few nm sides. The leakage currents with 2 probes at the atomic scale have thus been able to be measured on the surface of Si(100):H between two of these pads. To prepare the atomic contacts at least 2 probes on an atomic wire or on nanometric contact pads, we studied in detail the different types of contact points STM-single dangling bond showing the difficulty of reaching a quantum of conductance at contact, due to a possible bands bending. It is therefore difficult without a complementary force measurement to determine, starting from the tunnel contact, the different steps of the mechanical, electronic contact at the chemical contact. Our results open the way to the characterization of electronic circuits constructed atom-by-atom and at atomic scale on the surface of a semiconductor
26
Moc, Filip. "Vestavěný systém pro automatizaci chovné stanice akvarijních ryb." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2018. http://www.nusl.cz/ntk/nusl-385996.
Full textAbstract:
This master's thesis is concerned about embedded system for automatic water renewal in aquariums. Besides water renewal system also controls lights and ventilation in aquarium fish breeding station. In this report you will find informtions about technology relevant to automation of aquarium fish breeding station. Also you will find here informations about design and implementation of my specific final working solution.
27
Müller, Wolfhart. "Temperaturverhältnisse und Reaktionskinetik beim Ziehen und Wärmebehandeln von Draht." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-127084.
Full textAbstract:
Die Temperaturverhältnisse beim Ziehen und Wärmebehandeln von Draht werden mit mathematisch-analytischen Methoden auf der Grundlage der FOURIERschen Wärmeleitungsgleichung eingehend untersucht. Insbesondere wird unter den spezifischen Wärmeübergangsbedingungen zwischen Draht und Ziehdüse sowie zwischen Draht und Ziehtrommel deren thermische Wechselwirkung analysiert. Ein Näherungsverfahren zur Berechnung der Drahttemperaturen in Zugfolgen unter Berücksichtigung des Ziehdüseneinflusses wird angegeben und mit einem Beispiel zum Nassziehen stark verzinkten Stahldrahts illustriert. Aus geschwindigkeitsabhängig gemessenen Änderungen des Drahtdurchmessers werden unter thermoelastischer Ziehringdurchmesserkorrektur Schmierfilmdicken bestimmt. Diffusionsgleichungen werden analysiert und ein Zusammenhang zur Reaktionskinetik wird hergestellt. Ein neues reaktionskinetisches Werkstoffmodell, das insbesondere auch im Falle stärker anisothermer Verhältnisse, also bei Kurzzeitwärmebehandlung anwendbar ist, wird vorgestellt.
28
Mulpuri, Vamsi. "Failure Analysis and High Temperature Characterization of Silicon Carbide Power MOSFETs." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron151076214366849.
Full text
29
Jullien, Jean-Baptiste. "Etude de fiabilité et définition de modèles théoriques de vieillissement en très haute température pour des systèmes électronique et microélectronique." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14604/document.
Full textAbstract:
Ce travail s'intègre dans les domaines de l'analyse et de la prédiction de la fiabilité des assemblages Multi-Chip Module. Il présente l'étude de fiabilité de microcâblages filaires (wire bonding) en très haute température à partir d'essais de vieillissement et d'analyses expérimentales. Les résultats permettent d'identifier les mécanismes de dégradation et d'évaluer les températures limites d'utilisation de ces interconnexions. Il développe une étude du comportement thermomécanique des joints collés à partir d'essais de caractérisation mécanique, d'essais de vieillissement accéléré et de simulations numériques par éléments finis. Ces méthodes permettent d'évaluer la criticité des assemblages dès la phase de conceptionThis work is performed in analysis and prediction areas of Multi-Chip Module package reliability. It presents a reliability study on wire bonding in high temperature environment from aging tests and experimental analyzes. Results permit to identify degradation mechanisms and evaluate temperature limits of these interconnections. It develops a study of the thermomechanical behavior of adhesive joints from mechanical characterization tests, accelerated aging tests and finite element simulations. These methods are used to assess the criticality of packages from the design phase
30
Zapoticla, Frank. "The Effects of Applied Strain and Heat Treatment on the Properties of NiTi Wire During Shape Setting." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/378.
Full textAbstract:
NiTi components are commonly subjected to thermo-mechanical heat treatments during production and fabrication. This study investigates the effects of applied strain of 0-10% and heat treatments of 300-600ºC for times of 2-30 minutes during shape-setting of Ti–50.8 at% Ni wire with a nominal diameter of 0.495 mm and an initial transition temperature, Af, of 12ºC. Strain was applied prior to heat treatments by coiling NiTi wire, essentially producing coiled springs, around different diameter steel mandrels to obtain different strain levels. The samples of NiTi wire under applied strain were heat treated in a salt bath, followed by a rapid quench. Transformation temperatures and mechanical properties were characterized using the differential scanning calorimeter and tensile tests. Changes in the Af, UTS, and elastic modulus due to ageing processes and applied strain were observed. Following theory, precipitation rates of Ni-rich phases generally increased with increased temperature (up to a certain point), time and applied strain levels. Reaction rates to achieve a particular Af might be faster than expected if the sample is under strain during the shape-setting process. Due to precipitation strengthening, an increase in UTS with increased heat treatment time was observed between 300-450°C; annealing processes dominate at higher temperatures, resulting in a decrease in UTS above 500°C. A decrease in UTS with increasing level of applied strain was observed. Trends in elastic modulus were highly inconsistent in this study. As shown by this study, applied strain in NiTi during heat treatment affects the Af and mechanical properties.
31
Montagnac, Gilles. "Spectroscopie Raman résonnante UV in situ à haute température ou à haute pression." Thesis, Lyon, École normale supérieure, 2012. http://www.theses.fr/2012ENSL0784/document.
Full textAbstract:
Dans cette thèse, la spectroscopie Raman résonante UV (SRRUV) est appliquée pour la première fois à l'étude ‘in situ’ de matériaux carbonés à très haute température (> 2000 K) ou à haute pression (< 1 GPa).La thèse est constituée de trois parties. La première aborde notre travail de caractérisation en SRRUV (1) de films semi conducteurs de diamants ultra-nano-cristalins, (2) des kérogènes issues de météorites chondritiques et de charbons, et (3) des tholins, échantillons de carbone-hydrogène-azote, synthétisés comme analogues de l'atmosphère de Titan.L’intérêt pour ces phases du carbone en planétologie et en science des matériaux nous a poussé à mettre en œuvre leur étude ‘in situ’ en SRRUV. La seconde partie de la thèse est consacrée au développement d'une platine chauffante, grâce à laquelle les spectres Raman du graphite sous sa forme pyrolitique et HOPG ont été mesurés jusqu'à 2700 K. Ces données valident les modèles anharmoniques théoriques d’interaction électron-phonon et phonon-phonon. Le spectre Raman du graphite a été étalonné en fonction de la température et devient un « thermomètre » à très haute température.Dans la troisième partie de cette thèse, une presse à enclumes opposées a été modifiée pour suivre en SRRUV les changements structuraux de cristaux moléculaires très luminescents. Les vibrations intramoléculaires du cristal de pérylène sont étudiées sous pression par SRRUV. Ce composé est un cristal formé de molécules organiques polyaromatiques, avec des propriétés de semi-conducteur. Les effets de la pression sur certains modes de vibrations sont non linéaires et mettent en évidence des changement structuraux et de planéité de la moléculeI applied UV resonant Raman spectroscopy (UVRRS) to an ‘in situ’ study of carbon materials at very hight temperature (> 2000 K) or at high pressure (< 1 GPa).The advantages of UVRRS are presented in the first part of this PHD thesis, and used to investigate details of the composition and structure of disordered carbon materials such as: (1) n-type nanocrystalline films, (2) carbonaceous matter in chondrites and (3) tholins, HCN synthetic samples of Titan 's atmosphere.‘In situ’ Raman studies are limited to 2000 K by the visible black-body emission. I designed a high temperature cell to perform UVRRS above this limit. The second part of the manuscript presents Raman spectra of pyrolitic graphite and HOPG up to 2700 K. This data are consistent with anharmonic models up to 900 K, and show the coupling effects of electron-phonon and phonon-phonon. The last one dominates the anharmonicity above 1000 K. The Raman spectra was calibrated as a function of temperature and became a “thermometer” up to 2700 K.For high pressure measurements in the third part, I modified an anvil cell to study by UVRRS, the vibrational changes induced by pressure on very luminescent molecular organic crystals. I present an analysis at 244 nm of resonant Raman modes of perylene crystal under hydrostatic pressure up to 0.8 GPa. Some of them have a non linear feature under pressure, revealing structural and planar modifications of the molecules
32
Netáhlo, Tomáš. "Palubní multifunkční jednotka pro motocykly." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219822.
Full textAbstract:
Master’s thesis deals with a design and a realization of multifunction board computer for motorcycles. The goal of the device is measuring speed, rotation speed of engine, temperature of ambient, temperature of engine, temperature in intake including signalization of overvoltage and hightemperature. The device is completed by above standard function such as measuring titl of motorcycle, climbing of route, route recording and data transmission to the computer. The thesis includes a complete solution of hardware and software part of the device.
33
Khedekar, Mayur. "Temperature Based Estimation of the Time-Resolved Massflux of ICE Exhaust Gas Flow." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300050.
Full textAbstract:
The aim ofthe study was to provideinformation and experience gained with fine wire thermocouples (TCs)or resistance wire thermometers (RWTs) temperature signals to estimate the timeresolved heat transfercoefficient. Constant current method was assumed in the study and medium used in this study was air. Here the heat balance equation has been described, different Nucorrelations and further discusses potential hurdles and difficulties one may encounter while calculating heat transfer coefficient. As asolution, the use of an appropriate heatbalance equation and lowpass filter was suggested as this provides a more accurate fitting. The investigation was carried out for Reynolds number (Re) 103 to 107 and Prandlt number (Pr) 0.734. The impact of the Re and Pr on the Nusselts number (Nu) around a cylinder was represented and all the results were compared with GT-POWER engine simulation software.Syftet med studien var att tillhandahålla information och erfarenhet från fina trådtermoelement (TC) eller motståndstrådstermometrar (RWT) temperatursignaler för att uppskatta den tidsupplösta värmeöverföringskoefficienten. Metoden med konstant flöde antogs i studien och mediet som användes i denna studie var luft. Här har värmebalansekvationen beskrivits, olika Nu-korrelationer och diskuterat ytterligare potentiella hinder och svårigheter man kan stöta på vid beräkning av värmeöverföringskoefficienten. Som en lösning föreslogs användning av en lämplig värmebalansekvation och lågpassfilter eftersom detta ger en mer exaktpassform. Undersökningen genomfördes för Reynoldsnummer (Re) 103 till 107 och Prandlt nummer (Pr) 0,734. Effekten av Re och Pr på Nusselts-numret (Nu) runt en cylinder representerades och alla resultat jämfördes med GT-POWER-motorns simuleringsprogram.
34
Müller, Jan. "Kondenzační technika a odvody spalin." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226844.
Full textAbstract:
This thesis is developed as a proposal for heating for a primary school and kindergarten in the region of Brno-countryside. For the insulated building, a combination of heating and air-conditioning is proposed. The concept is designed so that the air-conditioning preheats the exterior air and the heating system warms the incoming air to a comfortable temperature. For the required thermal performance, sources of heat (for gas and pellets) and a layout solution for the boiler room is designed. Drainage of combustion products is proposed for both solutions. The project solution is per the extent of the construction permit. The theoretical part is linked with the practical part through the condensation boilers, their function and division, and drainage of combustion products. The experiment for the given topic was conducted on the drainage of combustion products. The pressure loss of the reverse knob was determined in relation to the flow rate of air in the condensation boilers as this loss is essential in assessing the drainage of combustion products.
35
Huang, Chen-may, and 黃岑媺. "Temperature and bias ffect on wire-bond reliability for F1 & S2 type new wire evaluatione." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/20379477546579426092.
Full text
36
Lue, Min-Hsien, and 呂旻憲. "Temperature, Bias Effect and Chloride Ion on Wire-Bond Reliability." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/34071780021125266554.
Full text
37
HUANG, CHIN-CHUN, and 黃誌君. "Study on the Plastic Behavior of Fastener Wire at High Temperature." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/zzk74x.
Full textAbstract:
碩士高苑科技大學
機械與自動化工程研究所
106
The isothermal hot compression test for the 1022 and SCM435 steel rod in the range of 800oC~900oC at strain rate of 1*10-3s-1~1*10-1s-1 was done. And analysis for the deformation behavior of the steel at high temperature by measuring the flow stress and constructing the thermal processing map using dynamic materials model has also been carried out. The results show that the maximum flow stress decreases significantly with increasing deformation temperature in strain rate range from 1*10-3s-1 to 1*10-1s-1. The steel exhibits higher strain rate sensitivity and power dissipation efficiency at lower deformation temperature and lower strain rate, and it is more sensitive to temperature at higher strain rate. The steel shows a flow instability in deformation temperature range from 800oC to 860oC and strain rate range from 1*10-3s-1 to 1*10-1s-1, and it also clarifies flow instability around 900oC at 1*10-1s-1. The result presents a better workability of the steel in deformation temperature range from 860oC to 900oC and strain rate range from 1*10-3s-1 to 1*10-2s-1, and at 900oC/1*10-3s-1 is the best one, that is at the highest deformation temperature and the lowest strain rate.
38
Rezaey, Reza. "High Temperature Gas to Liquid Metal Foam and Wire Mesh Heat Exchangers." Thesis, 2012. http://hdl.handle.net/1807/33500.
Full textAbstract:
Metal foams and wire meshes are open cell structures with low weight and density, high permeability and high thermal conductivity which make them attractive for a wide range of industrial applications involving fluid flow and heat transfer. In this study, the effect of natural convection, radiation and heat transfer enhancement of metal foams and wire meshes of 10 and 40 PPI (pores per inch) heat exchangers were examined and compared for different heat exchanger orientation, coolant flow rate and atmosphere temperature.
Thermal spray coating processes were also used in development of a new class of high temperature stainless steel heat exchangers. Stainless steel wire mesh heat exchangers were prototyped by connecting the tube to the wire mesh using wire arc thermal spray coating. Thermal spray coating provided efficient connections between the wire mesh and the tubes’ outer surface, and has potential to replace expensive brazing or other metal connection techniques.
39
Huang, Po-Chun, and 黃柏鈞. "High-Performance Low-Temperature Polysilicon Thin-Film Transistors with Nano-wire Structure." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/46348x.
Full textAbstract:
碩士國立中山大學
物理學系研究所
95
In this thesis, we study the electrical characteristics of a series of polysilicon thin-film transistors (poly-Si TFTs) with different numbers of multiple channels of various widths, with lightly-doped drain (LDD) structures. Among all investigated TFTs, the nano-scale TFT with ten 67 nm-wide split channels (M10) has superior and more uniform electrical characteristics than other TFTs, such as a higher ON/OFF current ratio (>109), a steeper subthreshold slope (SS) of 137 mV/decade, an absence of drain-induced barrier lowering (DIBL) and a suppressed kink-effect. These results originate from the fact that the active channels of M10 TFT has best gate control due to its nano-wire channels were surrounded by tri-gate electrodes. Additionally, experimental results reveal that the electrical performance of proposed TFTs enhances with the number of channels from one to ten strips of multiple channels sequentially, yielding a profile from a single gate to tri-gate structure. In addition, we have also studied the multi-gate combining the pattern-dependent nickel (Ni) metal-induced lateral crystallization (Ni-MILC) polysilicon thin-film transistors (poly-Si TFTs) with ten nanowire channels. Experimental results reveal that applying ten nanowire channels improves the performance of Ni-MILC poly-Si TFT, which thus has a higher ON current, a lower leakage current and a lower threshold voltage (Vth) than single-channel TFTs. Furthermore, the experimental results reveal that combining the multi-gate structure and ten nanowire channels further enhances the entire performance of Ni-MILC TFTs, which thus have a low leakage current, a high ON/OFF ratio, a low Vth, a steep subthreshold swing (SS) and kink-free output characteristics. The multi-gate with ten nanowire channels NI-MILC TFTs has few poly-Si grain boundary defects, a low lateral electrical field and a gate channel shortening effect, all of which are associated with such high-performance characteristics. The PDMILC TFTs process is compatible with CMOS technology, and involves no extra mask. Such high performance PDMILC TFTs are thus promising for use in future high-performance poly-Si TFT applications, especially in AMLCD and 3D MOSFET stacked circuits. Otherwise, we have investigated the mechanism of the leakage currents in polysilicon TFT with different temperature and applied biases. Moreover, we have simulated the electric fields in different structure polysilicon TFT to explain the mechanism of the leakage currents. By comparing the leakage currents in different channel structures, the leakage current in nanowire channel structure is higher than that in non-nanowire channel structure. Moreover, the leakage current in multiple gate structure is lower than that in single gate structure. Therefore, these two experimental results are caused by high electric field in the drain-to-gate overlap and drain-to-body depletion region respectively.
40
蕭宇辰. "Development of a Digital Hot-wire Type Flow-meter with Temperature Compensation." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/47953936450778862942.
Full text
41
LI, YI-TA, and 李宜達. "Study on the Plastic Behavior of Boron Steel Wire at High Temperature." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/75qevc.
Full textAbstract:
碩士高苑科技大學
機械與自動化工程研究所
106
The isothermal hot compression test for the 10B21 and 10B33 boron steel rods in the range of 800oC~900oC at strain rate of 1*10-3s-1~1*10-1s-1 was done. And analysis for the deformation behavior of the steel at high temperature by measuring the flow stress and constructing the thermal processing map utilizing dynamic materials model has also been carried out. The results show that dynamic recrystallization is the main reason for softening flow at lower temperature and lower strain rate, on the contrary, it results from dynamic recovery at higher temperature and higher strain rate. For both of the steels strain rate sensitivity increases with decreasing strain rate at strin of 0.3 and at 800oC. Thus, the steel is sensitive to strain rate at the temperatures. Besides, it is more sensitive to temperature at lower strain rate. The 10B21 steel exhibits a better workability in deformation temperature range from 820oC to 880oC and strain rate range from 1*10-3s-1 to 1*10-1s-1, and at 850oC/1*10-3s-1 is the best one, it also has the highest power dissipation efficiency as well. But 10B33 steel, the best deforming condition is 850℃/1*10-1s-1. In the other hand, the 10B21 steel occurred significant inhomogeneous grain boundary distortion when deformation in the range of 800oC~810oC at strain rate of 1*10-3s-1~1*10-2s-1 and 880oC~900oC at strain rate of 1*10-2s-1~1*10-1s-1, this is responsible for the flow instability. However, the 10B33 steel occurred flow instability at differet strain rates.
42
Chang, Chung-Cheng, and 張忠誠. "A Sampled-Data Formulation for Boundary Temperature Control of A Threadlike Metal Wire." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/66963577613660398952.
Full textAbstract:
碩士國立中興大學
電機工程學系
93
This thesis presents an analytic solution to the boundary temperature control problem for a threadlike metal wire. With boundary conditions satisfying the regular form of Strum-Liouville problem, the infinite-dimensional linear heat-conduction equation can be formulated into an infinite sequence of discrete-time control problems. The finite-dimensional approximation of the discrete-time system is obtained by the minimum square error theorem of Fourier series. The controllability- observability conditions are related to the associated eigenvalues. As a verification to the proposed analytic solution, numerical simulations are conducted using both a Matlab partial differential equation solver, pdepe.m , and the proposed finite dimensional ordinary differential equation approximation.
43
Lai, Po-Ying, and 賴柏穎. "Effect of Palladium Distribution on High Temperature Storage Reliability of Palladium Coated Copper Wire." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/8k3yr7.
Full textAbstract:
博士國立交通大學
機械工程系所
106
With the progress of science and technology, electronic chips are developed in the trend of light, thin, short and small. Wire bonding within the chip plays an important role in connecting an integrated circuit to a substrate for transmitting signals and power. The connecting wires are also as a heat sink during the operation of the chip. In bonding process, palladium-copper wire will be changed and melted to form a free air ball (FAB). And the quality of the FAB will affect the shape forming and palladium distribution of the bonding ball. The incomplete coating of the palladium on the surface of the bonding ball. Since that it is easy to be corrosion during to the moisture and halogen ions in the epoxy molding compound (EMC), win result to the change of the bonding reliability. The EFO during the bonding process is an important factor that affects the distribution and cladding of palladium on the bonding balls. In this study, the electronic flame off (EFO) is the main topic in studying the affect of palladium distribution of palladium coated copper wire on high temperature storage reliability. Three EFO current parameters are selected for evaluating the result of the affect on palladium distribution. In the process of experimental analysis, high-magnification microscope and electron microscope were used to observe the dimensions and material at distribution of both the FAB and bonding ball. The distribution of palladium in the FAB and the bonding ball was observed by electron microprobe. In order to evaluate the effect of EFO current on the distribution of palladium on the surface of FABs and the bonding strength of bonding wire, the bonding strength and high temperature reliability test were performed before and after the specimen package. The first mechanical strength test was carried out before the package was unpackaged to evaluate whether the distribution of palladium on the surface of the bond ball would affect the bond strength of the bond ball without high temperature corrosion. After the sample is packaged, it is planned to place the sample at high temperature reliability test. The experiment is planned to evaluate the corrosion effect of the bonding ball as compared by using three EFO currents parameters. Finally, the second mechanical strength test was conducted again to evaluate the joint reliability of the bonding balls after being subjected to high temperature corrosion. The results of the present study show that the three kinds of EFO current parameters will cause different coverage of palladium on the surface of the FAB. However, the complete coverage of palladium on the FAB directly affects the distribution of palladium on the bonding sphere surface and the bonding interface. After high temperature reliability test of the sample, the results indicated that the bonding strength of the bonding balls tended to decrease. In addition, the FABs formed with the three kinds of EFO current conduct to the bonding balls with different surface conditions of potholes and cracks. From the high temperature reliability test results show that palladium can be used as a protective layer of the bonding balls, mitigation from the encapsulation of the halide ions and water vapor attack, the bonding ball of palladium coated incomplete or palladium into the alloy. Less coverage of the palladium on FAB and bonding ball, the corrosion area of the bonding ball is increased and expanded. The results of this research show that the optimum EFO current is obtained. This research result can provide a reference for the planning or improvement of the package process.
44
Jen-BangLo and 羅任邦. "Three-dimensional orthodontic force measurement system to evaluate the temperature effect on NiTi wire." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/u4v2uh.
Full textAbstract:
碩士國立成功大學
口腔醫學研究所
105
The movement of teeth during orthodontic treatment should be controlled in all three planes of space, including the crown and root position. Force and movement should be accurately known in order to move a tooth into the ideal position and avoid undesirable side effects such as additional visits, overloading, tissue necrosis or even root resorption. Nickel-titanium (NiTi) wires are widely used in orthodontics as they combine the shape memory and superelasticity resulting from phase transformation induced by stress or temperature. In this study, a 3D force measuring system was developed using cone-beam computerized tomography (CBCT) images and software (Mimics 10.01, Geometric studio 12 and Solidworks). The models were fabricated using a 3D printer (Up plus 2). A multi-axis force transducer, called Nano17 (ATI, USA), was used for the 3D orthodontic force and moment measurements. Four different types of NiTi wire (Nitinol, Sentalloy, 27°C CuNiTi, 40°C CuNiTi) with the same size (.016 x .022 inches) were used. Self-ligating brackets (H4, Orthoclassic, USA) were bonded on simulated teeth. The change in orthodontic force and moment can be observed inside temperature controlled box. The results revealed that there was a strong relation between temperature and orthodontic force for most brands of wires, except Nitinol (correlation coefficient: Sentalloy=0.964, 27°C CuNiTi=0.918, 40°C CuNiTi=0.946). Comparison of forces under different temperature among different NiTi wires also reached statistically significant difference. However, the moment and temperature did not show a very strong correlation. Nitinol expressed highest and 40°C CuNiTi expressed lowest moment among four groups. The 3D force measurement system can provide practical information for clinical use.
45
Sterner, Boström Måns. "Developing a measurement system of fluid velocities in rotating bed reactors." Thesis, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-123227.
Full textAbstract:
SpinChem AB's rotating bed reactor (RBR) is a small cylindrical centrifuge that allowsfor eective convective reactions between chemical substances. The aim of my master'sdissertation was to develop a measurement system that could estimate the uid velocity insidethe RBR. This report covers a quick pre-study of dierent uid measurement methods,details how we designed and constructed the system using integrated circuits and other electroniccomponents, and illustrates calibration results and nal velocity measurements. Thesystem design was based on the architecture of hot-wire constant temperature anemometry(CTA), a technique that measures the uid velocity over a heated metal wire. The resultsof this project is the measurement system itself, and the calibration and velocity measurementsgathered from experimentation. Two issues we encountered was that the calibrationprocess resulted in an overestimation of the velocity in the order of 4000 cm/s, and thatthe response to changes in velocity rates was quite slow. However, a slight tuning of thetwo calibration constants A0 & B0 smoothed the velocity estimation out to 40 cm/s, whichis more what we would expect. This illustrated how sensitive the results were to errors inthe calibration. Further investigation of the slow response, and a more stringently executedcalibration setup, could make the CTA a potential candidate for estimating the uid velocityinside the RBR.
46
Hao-WenHsueh and 薛皓文. "Effect of Annealing Temperature on Recrystallization and Tensile Properties of Wire Bonding 23μm Silver Wires." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/20558853373144805511.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系碩博士班
98
Silver is a novel wire material of wire bonding process because its excellent electrical and thermal properties, it’s more expensive than copper but cheaper than gold, and it’s lower hardness and hard to oxidative compared to copper. In this study, the effects of the microstrctures and tensile properties after annealing, EFO, wire bonding and electrical current test of the 23μm silver wire are studied. After the silver wires are annealed at 250℃ for 30minutes, the microhardness decreases to Hv 53±2 which is similar to gold and the tensile properties are steady because of recrystallization,. After the EFO process, there are 3~4 columnar grains in the FAB and HAZ in the wire whether the sample is annealed or not. According to the results of the microstructure and the microhardness, the lengths of HAZ in the as-drawn wire and annealed wire are 420μm and 220μm respectively. Due to the fact of forming HAZ, the strength is the lowest and strain concentration in this area, leading to the change of the tensile properties. In this study, I use two different Al subtrates, Al-bulk and Al-500nm thin film, as experiment’s bonding pads. Before the current test, the fracture of silver wire mainly occurs in the HAZ during the pull tests. After the current test, the fracture positions has shifted to the middle of new HAZ which is formed by the current test. Among the two substrates, Al-500nm thin film is more likely to fracture at the contact interface.
47
CHUANG, CHENG-YAO, and 莊承堯. "Texturization of diamond-wire-sawn single-crystalline Si using high temperature copper based acid solutions." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/xx2z46.
Full textAbstract:
碩士國立雲林科技大學
材料科技研究所
107
This work study surface texturization of diamond wire sawn (DWS) single-crystalline silicon wafer by metal assisted chemical etching (MACE). An unetched single-crystalline silicon wafer was used. A non-etched single crystal was etched in a Cu(NO3)2/HF/H2O2 solution at above 56 °C. The residual metal ions are removed by using HNO3 solution, and the oxide is removed by the HF solution. The surface morphology of the textured wafer was analyzed using a field emission scanning electron microscopy (SEM). UV/visible spectrophotometer was adopted to measure the reflectivity of the wafer. SEM analysis showed that {111} planes and inverted pyramid structures were successfully produced on the surface of a DWS wafer by using copper assisted chemical etching. Among them, the solution concentration, the etching temperature, and the etching time were found to greatly affect the surface structures. Reflectance measurements were made at an angle of 5 ° from the normal of the wafer. The average reflectivity of the unetched DWS wafer, an industry DWS wafer by using alkaline etching and the DWS wafer by using MACE at visible wavelength range (380 nm-750 nm) is about 3.4%, 0.2% and 0.08%, respectively. The reflectivity of all DWS wafers by using MACE is lower than the DWS wafers by using the industry alkaline etching. Therefore, the reflectivity of sunlight can effectively decline. SEM analysis shows that the parallel saw marks on the surface of a DWS wafer can be effectively removed by etching of wafers in Cu(NO3)2/HF/H2O2 solution. The inverted pyramid structures were successfully produced on the surface of a DWS wafer by using metal catalyst of copper through MACE. Keywords: texturization, diamond wire sawn wafer, copper nitrate
48
Powell, Benjamin Robert. "Constant temperature hot wire anemometry applied to the characterisation of a nozzle molecular beam source." Master's thesis, 2008. http://hdl.handle.net/1885/146501.
Full text
49
Richardson, Christine Esber. "Low-temperature hot-wire chemical vapor deposition of epitaxial films for large-grained polycrystalline photovoltaic devices." Thesis, 2007. https://thesis.library.caltech.edu/2812/1/CERthesis.pdf.
Full textAbstract:
Large-grained polycrystalline silicon thin-films on low-cost substrates are an interesting area of research for photovoltaic devices. Such devices, with grain sizes larger than the thickness of the cell, have the potential to achieve multicrystalline-like efficiencies of 15%, but at a much lower cost by taking advantage of thin-film manufacturing techniques. In this thesis, low-temperature epitaxial growth, by hot-wire (or catalytic) chemical vapor deposition, is investigated for the epitaxial thickening of large-grained polycrystalline silicon templates formed by metal-induced crystallization on low-cost substrates. Low-temperature hot-wire chemical vapor deposition allows for the deposition of epitaxial silicon with polycrystalline breakdown and with open-circuit voltages close to that of monocrystalline silicon. This is possible due to the incorporation of hydrogen into the silicon lattice, at temperatures below 350°C, for internal surface and defect passivation. In addition with hot-wire chemical vapor deposition, the critical epitaxial thickness actually increases, with a decrease in the substrate temperature down to temperatures of 270°C. Epitaxial growth of 5.5 micron thick films at 300°C and twinned epitaxial silicon growth of 6.8 micron thick films at 230°C have been achieved, along with arbitrarily thick crystalline films at low temperatures. Since epitaxial and high-quality crystalline silicon can be deposited at such low deposition temperatures, low-cost substrates, such as ordinary soda lime glass and many polymers are possible. In order to work towards achieving an epitaxially-thickened large-grained polycrystalline device, this work studies the mechanisms that lead to epitaxial growth during hot-wire chemical vapor deposition on silicon (100) substrates under various growth regimes, examines the surface evolution of crystalline thin-films grown via hot-wire chemical vapor deposition and their growth mechanisms (including the unusual rough epitaxial growth and arbitrarily thick crystalline films at low temperatures), and concludes by presenting the optical and electrical characteristics of these films and their resultant devices. This thesis demonstrates that low-temperature epitaxial silicon growth by hot-wire chemical vapor deposition is a promising material for low-cost thin-film silicon photovoltaic devices.
50
Ko, Yung-Long, and 柯雲龍. "Thin-film Thermocouple Fabricated by Sputtering Deposition in Application to Contacted Temperature Measurement during Ultrasonic Wire Bounding." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/88009959160687123622.
Full textAbstract:
碩士國立中正大學
機械系
88
Wire bonding, mainly responsible for electricity and signal delivery among devices, is a critical process in electronic package. Depending on the materials to be connected, the three often-used boding techniques are the thermocompression, ultrasonic, and thermosonic wire bondings. Although these techniques have been used for years, the detailed bonding mechanism is still unclear. Some researchers believed that the boding is due to re-solidification of melting that is induced by heat generation from friction caused by the fast relative motion between wire and metal surface. Others, however, thought the metallic bonding was formed due to free electrons exchanged during fast friction process and no melting occurred. So far no direct experimental evidence is obtainable for the bonding mechanism. The time history of contact temperature is a good indicator for this understanding. During the bonding process, if the contact temperature was higher than the melting temperature, the melting and re-solidification should be a reasonable mechanism. Otherwise, the mechanism could be the latter. From the literature, the available experimental study showed that the contact surface temperature was about 80oC. This low temperature might be due to using an oversized and insensible temperature sensor. In the present study a thin-film, K-type thermocouple, 80m in width, fabricated by sputtering deposition is used to measure the transient temperature during the bonding process. Result shows that the contact temperature was up to 170oC. Thus it is reasonable to conjecture that contact temperature can be even higher if a more smaller temperature sensor is used.