Tesis sobre el tema "Protective measurement"
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Sarkar, Mustafa. "The assessment of psychological resilience in sport performers". Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/17616.
Texto completoFrňka, Tomáš. "Bezdotykové měření povrchových teplot ve strojírenství". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228826.
Texto completoAl-Busaidi, Adil S. "Toward a Model of Organizational Muted Dissent: Construct Definition, Dimensions, Measurement, and Validation". Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1407242598.
Texto completoMerkle, Shannon L. M. "Exploring pain & movement relationships: is greater physical activity associated with reduced pain sensitivity & does endogenous muscle pain alter protective reflexes in the upper extremity?" Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2245.
Texto completoBálint, Zoltán. "Průvlekový transformátor proudu 25 kV, 400/5/5 A". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217917.
Texto completoQuint, Ryan David. "Practical Implementation of a Security-Dependability Adaptive Voting Scheme Using Decision Trees". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35667.
Texto completoMaster of Science
Hoang, Van Hung. "Electrochemical Synthesis of Novel Polyaniline-Montmorillonite Nanocomposites and Corrosion Protection of Steel". Doctoral thesis, Universitätsbibliothek Chemnitz, 2007. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200700059.
Texto completoDiese Dissertation beschreibt eine neue elektrochemische Synthese neuartiger Compositmaterialien basierend auf dem Tonmineral Montmorillonite (MMT) und intrinsisch leitfähigem Polyanilin (PANI). Die Elektropolymerisation von Aniliniumionen, welche in die Tonmineralschichten eingebaut sind, wurde bei einem konstanten Potenzial durchgeführt. Das resultierende organisch-anorganische Hybridmaterial PANI-MMT wurde mit verschiedenen physikochemischen Methoden charakterisiert. Die Ergebnisse der Elementaranalyse zeigen, dass nur 10 % des Nanocompositmaterials aus leitfähigem PANI bestehen. Die Vergrößerung des Zwischenschichtabstandes von MMT, die bei Röntgendiffraktometrieuntersuchungen beobachtet wurde, lässt auf die Bildung von PANI innerhalb der Tonmineral-Taktoide schließen. IR-spektroskopische Untersuchungen deuten auf das Vorhandensein von Wechselwirkungen physikochemischer Art, wahrscheinlich Wasserstoffbindungen zwischen dem Tonmineral und Polyanilin, hin. Untersuchungen mit zyklischer Voltammetrie zeigten, dass die Anwesenheit von elektroinaktivem Tonmineral die elektrochemische Aktivität von PANI nicht beeinflusst. Das elektrochrome Verhalten von PANI-MMT Nanocompositen wurde mit UV-Vis-Spektroskopie untersucht, wobei sich herausstellte, dass das elektrochrome Verhalten vom PANI im Compositmaterial erhalten bleibt. Eines der technologischen Hauptanwendungsgebiete von leitfähigen Polymeren, insbesondere von PANI, ist der Korrosionsschutz von aktiven Metallen. PANI-MMT Nanocomposite die mit der angegebenen Methode (elektrochemisch) synthetisiert wurden und chemisch synthetisiertes in organischen Medien lösliches PANI wurden zum Korrosionsschutz von C45 Stahl eingesetzt. Die Korrosionsuntersuchungen wurden mit Hilfe von elektrochemischen Impedanzmessungen (EIM) und anodischen Polarisationsuntersuchungen durchgeführt. Der von PANI-MMT und von in organischen Medien löslichem PANI gebotene Korrosionsschutz ist wahrscheinlich auf die Zunahme des Ladungsdurchtritts widerstandes der beschichteten Stahloberfläche zurückzuführen. Die anodische Verschiebung des Korrosionspotenzials, eine Verringerung der Korrosions-geschwindigkeit und eine deutliche Zunahme des Polarisationswiderstandes sind eindeutige Hinweise für das Antikorrosionsvermögen von PANI-MMT und auch von in organischen Medien löslichem PANI, welche auf der zu schützenden Stahloberfläche abgeschieden wurden
Jalandoni, D. Jay Moreno. "In-phantom measurement of HE or neutron protection dosimetry". Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/16777.
Texto completoTania, Mutmainna. "Wide Area Measurement Applications for Improvement of Power System Protection". Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/19241.
Texto completoIn addition to the slow but steady variations in the network structure over a long term, the grid also experiences drastic changes during the occurrence of a disturbance. One of the main reasons why protection relays mis-operate is due to the inability of the relays to adjust to the evolving network scenario. Such failures greatly compound the severity of the disturbance, while diminishing network integrity leading to catastrophic system-wide outages. With the advancement of Wide Area Measurement Systems (WAMS), it is now possible to redesign network protection schemes to make them more adaptive and thus improve the security of the system.
Often flagged for exacerbating the events leading to a blackout, the back-up distance protection relay scheme for transmission line protection and the loss-of-field relay scheme for generator unit protection can be greatly improved from an adaptability-oriented redesign. Protection schemes in general would benefit from a power re-distribution technique that helps predict generator outputs immediately after the occurrence of a contingency.
Ph. D.
Cong, Yuhang. "Synchronized measurement technology supported operational tripping schemes". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/synchronized-measurement-technology-supported-operational-tripping-schemes(7d472659-d352-4291-96fc-fce7e6ce5fc8).html.
Texto completoHuang, Chiung-Yi. "The application of phasor measurements for adaptive protection and control". Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/42131.
Texto completoThis thesis describes an adaptive protection scheme that performs the collection of the voltage and
current phasors during post-fault period, tracking the power swing phenomena, identifying the onset
of instability, and then issuing a stabilizing command. In this work, the protection system is to
maintain the reliability! ensure the secure operation, and prevent total collapse of the power system.
The work is based upon methods of clustering for meter placement in a bulk power system, and
selecting the pilot points for installing the phasor measurement units (PMU) to measure the bus
voltage phasors and associated branch current phasors. According to the network law, fast calculation
of state estimation can be made from these measurements. Because the on-line assessment
of transient stability has to provide a quick and approximate result, the direct method which determines
stability without explicit integration techniques is applicable in this study.
The results of the system stability prediction in real-time by digital computer simulation under
stable and unstable operating conditions are presented.
Master of Science
Adewole, Adeyemi Charles. "Voltage stability assessment and wide area protection/control using synchrophasor measurements". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2380.
Texto completoElectric power systems are being operated closer to their designed stability limits due to the constraints caused by the continuous increase in system loading, and the lack of new power stations and transmission network infrastructure to support this increase in system loading. This coupled with the practice of long distance bulk power transmission and cascading contingencies, makes system instability and consequently blackouts inevitable. In such scenarios, system instabilities like voltage instability becomes a serious threat to the secure operation of the power system, and voltage collapse (system-wide blackouts) are prone to occur. This is often compounded by the unavailability of real-time system measurements for situational awareness from the existing Supervisory Control and Data Acquisition (SCADA)/Energy Management System (EMS) platforms which are usually based on unsynchronized SCADA measurements with a slow reporting rate of 1 measurement every 2-10 seconds. This Doctoral thesis proposes non-iterative algorithms and methods of solution based on the IEEE C37.118 synchrophasor measurements from Phasor Measurement Units (PMUs) with a high reporting rate of up to 200 measurements every second (200 fps) for voltage stability assessment and automated wide area Centralised Protection/Control (CPC) against catastrophic voltage instabilities/blackouts in power systems. Extended formulations are proposed for the Optimal Placement of PMUs (OPP) in power systems with respect to voltage stability assessment. The impact of zero injection buses, critical buses, and PMU redundancy is considered in the formulation of the OPP problem solution. The extended formulations made use of Binary Integer programming (BIP) and Modal Participation Factors (MPFs) derived from the eigenvalues of the power flow Jacobian.
Elayyan, H. S. B. "Protection of high voltage systems against surge voltages : New models and measurement techniques". Thesis, Cardiff University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378453.
Texto completoPal, Anamitra. "PMU-Based Applications for Improved Monitoring and Protection of Power Systems". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/51093.
Texto completoPh. D.
Wrinch, Michael C. "Negative sequence impedance measurement for distributed generator islanding detection". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/3418.
Texto completoMthunzi, Everett Mondliwethu. "Performance analysis of a protection scheme based on P-class synchrophasor measurements". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2378.
Texto completoPower grid and system protection advancement greatly depend on technological advances. Advent technologies like digital microprocessor type protective relays facilitate paradigm shifts, providing inimitable beneficial engineering adaptations. Phasor measuring technology provides one such technological advance. The onset and rapid development of the Phasor Measuring Unit (PMU) provides an excellent platform for phasor-based, power system engineering. Power transmission constitutes a critical section in the electric power system. The power system transmission lines are susceptible to faults which require instant isolation to establish and maintain consistent system stability. This research focuses on the study of transmission line protection based on P-Class synchrophasor measurements. The IEEE C37.238-2011 Precision Time Protocol (PTP) paradigm shift facilitates practical application of synchrophasors in protection schemes. Synchrophasor procession and accurate data alignment over wide areas support the hypothesis of a phasor-based transmission line differential protection. This research aims to directly implement P-Class synchrophasors in transmission line differential protection, employing synchrophasors to determine fault conditions and administer corresponding protective actions in wide area transmission lines. The research also aims to evaluate the operational characteristics of the synchrophasor-based transmission line differential protection scheme. The research deliverables include a laboratory scale Test-bench that implements the PMU-based transmission line differential protection scheme, and a differential protection utility software solution that follows guidelines specified by the C37.118-2011 standard for synchrophasors. The findings stand to evaluate performance of the PMU-based line differential protection scheme, verifying the protection model as an alternate, practical and feasible backup protection solution. The research deliverables include a synchrophasor-based current differential algorithm, software utility for implementing the PMU-based protection scheme and a Test-bench for concept and feasibility validation.
Mauney, Daniel W. "Investigation of physical and psychophysical methods for the attenuation measurement of circumaural hearing protectors with implication for field use". Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40073.
Texto completoPh. D.
Roscoe, Andrew. "Measurement, control and protection of microgrids at low frame rates supporting security of supply". Thesis, University of Strathclyde, 2009. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=23787.
Texto completoLu, Zhen. "Development of advanced power system protection and power quality measurement algorithms using mathematical morphology". Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433041.
Texto completoFan, Dawei. "Synchronized Measurements And Applications During Power System Dynamics". Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26115.
Texto completoPh. D.
Ejenstam, Lina. "Hydrophobic and superhydrophobic coatings for corrosion protection of steel". Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175405.
Texto completoEftersom metaller, och då särskilt stål, är viktigta konstruktionsmaterial i vårt moderna samhälle är korrosionsskydd av stor betydelse, både för att garantera säkerhet och för att minska kostnader som uppkommer i samband med korrosion. Tidigare har sexvärt krom och andra skadliga ämnen använts för att på ett effektivt sätt skydda stål från korrosion, men efter att deras användning kraftigt reglerades runt år 2000 har ännu ingen beläggning utvecklats som helt kan ersätta krombeläggningarna med avseende på funktion.I denna avhandling har hydrofoba och superhydrofoba ytbeläggningar och deras möjliga applikation som en del av ett korrosionsskyddande beläggningssystem studerats. Eftersom korrosionsmekanismen är beroende av närvaron av vatten, är användandet av en superhydrofob beläggning för att fördröja transporten av vatten till den underliggande metallytan intuitiv. De korrosionsskyddande egenskaperna hos superhydrofoba ytbeläggningar utvärderades här främst med hjälp av kontaktvinkelmätningar och elektrokemisk utvärdering i korrosiv lösning bestående av 3 vikts% NaCl i vatten.Först undersöktes skillnaden i korrosionsskydd som uppnås vid användandet av ytbeläggningar med olika hydrofoba vätningsregimer med hjälp av ett modellsystem bestående av ett alkylketendimer vax. Det konstaterades att superhydrofobicitet i Lotusregimen är överlägset bättre än de andra hydrofoba vätningsregimerna, i alla fall när man ser till relativt korta exponeringstider, typiskt mindre än tio dagar. Detta beror på att den kontinuerliga luftfilm som kan bildas på en sådan typ av superhydrofob yta kan minska transporten av elektrolyt (som innehåller korrosiva joner) till metallytan till den grad att den elektriska kretsen bryts. Eftersom korrosion inte kan ske utan en sluten elektrisk krets är detta ett mycket effektivt sätt att förhindra korrosion från att ske.Ett luftskikt på en superhydrofob yta nedsänkt i vatten är dock inte stabilt under lång tid. För att undersöka möjligheten till korrosionsskydd under längre tid med hjälp av hydrofoba beläggningar utvecklades en hydrofob ytbeläggning bestående av polydimetylsiloxan och hydrofoba nanopartiklar av kiseldioxid. Detta system visade en förbättring av korrosionsskyddet vid ökat partikelinnehåll upp till den koncentration (40 wt%) där i stället sprickbildning i ytbeläggningen observerades. Från detta system kunde slutsatsen dras att matrisens och partiklarnasvihydrofobicitet i kombination med den längre diffusionsvägen som partiklarna orsakade förbättrade korrosionsskyddet av den underliggande metallen.För att ytterligare förstå hur hydrofobicitet och partikeltillsatser påverkar en ytbeläggnings korrosionsskyddande egenskaper har dessutom ett treskikts kompositbeläggningssystem utvecklats. Genom att använda detta beläggningssystem, som består av en basbeläggning av polyesterakrylat, ett lager TiO2-partiklar (med en diameter på <100 nm) slutligen belagt med ett tunt ytskikt bestående av hexametyldisiloxan så kunde slutsatsen dras att både en hydrofob matris och partiklar behövs för att nå en markant förbättring av ytbeläggningens korrosionsskyddande egenskaper.
QC 20151015
Palizban, Atefeh. "Wide-area monitoring and control utilizing PMU measurements for a system protection scheme". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52888.
Texto completoApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Janssen, Pierre. "Monitoring, protection and fault location in power distribution networks using system-wide measurements". Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209366.
Texto completoThanks to cost reductions and improvement of information and communication technologies, future distribution networks will probably have advanced communication infrastructures and more measurement devices installed in order to manage the increasing complexity of those networks, which is primarily caused by the introduction of distributed generation at the distribution level.
Therefore this thesis investigates how the monitoring, protection and fault location functions can be improved by using system-wide measurements, i.e. real-time measurements such as synchronized voltage and current measurements recorded at different network locations. Distributed synchronized measurements bring new perspectives for these three functions: protection and fault location are usually performed with local measurements only and synchronized measurements are not common in monitoring applications. For instance, by measuring distributed generators infeed together with some feeder measurements, the protection is expected to be more sensitive and selective and the fault location to be more accurate.
The main contribution of this work is the use of state estimation, which is normally only used for network monitoring, for the protection and the fault location.
The distribution system state estimation is first developed using the classical transmission system approach. The impact of the placement of the measurement devices and of a relatively low measurement redundancy on the accuracy, on the bad data detection and on the topology error identification capabilities of the estimator are discussed and illustrated. This results in recommendations on the placement of the meters.
Then, a backup protection algorithm using system-wide measurements is presented. The coherence of the measurements and the healthy network model are checked thanks to a linear three-phase state estimation. If the model does not fit to the measurements and if the estimated load is too high or unbalanced, a fault is detected. The advantages of the method are that the voltage measurement redundancy is considered, improving the detection sensitivity, and that load models may be considered in the algorithm, avoiding the need to install measurement devices on every line of the network.
Finally, two new impedance-based fault location algorithms using distributed voltage and current recordings are proposed. By defining statistical errors on the measurements and the network parameters, a method to compute a confidence interval of the fault distance estimate is proposed. The fault location accuracy and its sensitivity to the fault conditions (e.g. fault resistance or fault type) and to the different sources of error are assessed on a simulated distribution system.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Daggupati, Naga Prasad. "Assessment of the varitarget nozzle for variable rate application of liquid crop protection products". Thesis, Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/414.
Texto completoHo, Wing-kwok y 何永國. "Solar ultraviolet radiation: monitoring, dosimetry and protection". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31222675.
Texto completoOliver, Hannah Elizabeth. "The impacts of optical radiation in the environment on skin : hazards, measurement, regulation and protection". Thesis, Brunel University, 2006. http://bura.brunel.ac.uk/handle/2438/5329.
Texto completoTanny, Sean M. "Investigation of Radiation Protection Methodologies for Radiation Therapy Shielding Using Monte Carlo Simulation and Measurement". University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1449853114.
Texto completoFranzen-Korzendorfer, Holly. "Effects of monochromatic infrared energy on transcutaneous oxygen measurements in diabetic subjects with a loss of protective sensation". Diss., NSUWorks, 2006. https://nsuworks.nova.edu/hpd_pt_stuetd/15.
Texto completoBernabeu, Emanuel. "Methodology for a Security-Dependability Adaptive Protection Scheme based on Data Mining". Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/30131.
Texto completoPh. D.
NGUYEN, Ngoc Trung. "Study and development of innovative measurement methods and systems for anti-islanding protection in smart grids". Doctoral thesis, Università degli Studi di Palermo, 2014. http://hdl.handle.net/10447/90786.
Texto completoBell, Kenneth Frazer. "Measurement of the deposition of aerosol particles to skin, hair and clothing". Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/8608.
Texto completoBogue, Jonathan Nelson. "Evaluation of Patient-Scatter Factors for Radiation Therapy ShieldingUsing Physical Measurement in a "Good" Geometry". University of Toledo Health Science Campus / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=mco1525447575821026.
Texto completoBOCK, III EDWARD LAWRENCE. "PRACTICALITY OF USING AIR LEAD MEASUREMENTS BY PORTABLE X-RAY FLUOURESCENCE TO MANAGE WORKER PROTECTION PROGRAMS". University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022196683.
Texto completoSeydaliev, Marat Radikovich. "Development and Test of a GEM-Based TEPC for Neutron Protection Dosimetry". Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14607.
Texto completoBesar, Idris Bin. "Studies of the hazards of actinide contamination to man and methods of body measurement". Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323396.
Texto completoAzzopardi, Alexander. "Measurement of erosion and protecting exposed dentine with an adhesive resin coating : an in-vitro and in-situ evaluation". Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394247.
Texto completoSzwer, David James. "High fidelity readout and protection of a 43Ca+ trapped ion qubit". Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515002.
Texto completoStylemans, Eric. "Etude d'un système de contre-mesure électroacoustique anti sous-marin destiné à la protection des navires". Valenciennes, 1997. http://www.theses.fr/1997VALE0007.
Texto completoAlexandre, Armando Emanuel Mocho fernandes e. "Wave energy converter strings for electricity generation and coastal protection". Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/wave-energy-converter-strings-for-electricity-generation-and-coastal-protection(c7d53691-22f6-4ea8-a7ec-c9850218a1d5).html.
Texto completoUddin, Salman. "A novel approach to detect CT saturation using standalone CT measurements". Thesis, KTH, Elkraftteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214076.
Texto completoKraven pa tillforlitlighet och sakerhet i kraftsystem okar varje dag i samband med allthogre komplexitet i kraftsystemet. For att uppna den hogsta nivan av tillforlitlighetbehover relaskydden ta emot korrekta matvarden fran kraftsystemet. Ett av de mest viktigamatvardena som behovs for ett relaskydd ar strom. Emellertid, kan matvarden franen stromtransformator bli felaktiga pagrund av ett fenomen som kallas stromtransformatormattning. Malet for detta examensarbete ar att skapa en ny algoritm for relaskydd somdetekterar stromtransformatormattning. Algoritmen ska baseras pa en fristaende metodsom klarar av att detektera stromtransformatormattning inom 1-2 ms for en samplingsfrekvenspa 4 kHz.Detta projekt omfattar, forutom en studie av hur stromtransformatormattning kan detekteras,aven en bakgrundsstudie om stromtransformatorer och stromtransformatormattning.Viktigare existerande metoder, som anvands i industrin for att detektera stromtransformatormattning, undersoks i detalj och modelleras i Simulink. En ny metod foreslas foratt exklusivt detektera stromtransformatormattning med hansyn till de strikta krav somfaststalldes i borjan av projektet. Den foreslagna metoden ar implementerad i Simulinkoch i HiDraw (en intern ABB mjukvara for att skapa C-kod for skyddsfunktioner). Slutligenar den nya foreslagna metoden och de existerande metoderna testade i Simulinkmed er an 1300 testfall baserade paolika forhallanden i kraftsystemet, IEC-60255-187-1standarden och med verkliga inspelningar av strom gjorda av relaskydd i drift.Resultatet av testerna visar att den nya foreslagna metoden framgangsrikt detekterarstromtransformatormattning och gor det battre an existerande metoder med avseende pasnabbhet och noggrannhet. Det konstaterades att den nya foreslagna metoden framgangsriktdetekterar stromtransformatormattning och darfor kan anvandas for vilken relaskyddsfunktionsom helst i ett relaskydd dar behovet av att detektera stromtransformatormattningnns.
Tsutsumi, Takuya. "Field Measurement and Analysis of Next-Generation Optical Access Network with Optical Amplifiers". Kyoto University, 2018. http://hdl.handle.net/2433/232417.
Texto completoThomas, Michael Kyle. "Implementation of the Security-Dependability Adaptive Voting Scheme". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/32542.
Texto completoMaster of Science
Papier, Mark Elliot. "Real-time measurement of on-road fine particulate matter in Atlanta". Thesis, Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22544.
Texto completoYounis, Ahmed. "Protection of Aluminum Alloy (AA7075) from Corrosion by Sol-Gel Technique". Doctoral thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-83230.
Texto completoThe present work pertains to the development of sol-gel coatings by optimizing the composition and the application parameters for corrosion protection of aluminum alloy AA7075. Different kinds of silanes e.g. tetraethoxysilane (TEOS), phenyltriethoxysilane (PTES) and phenyltrimethoxysilane (PTMS) have been compared: the sol-gel film prepared from PTMS shows highest hydrophobicity manifested by the best barrier property of this compound. The effect of acetic acid as a catalyst on the chemistry of the sol is investigated in order to estimate the best catalyst concentration for better corrosion protection of the coated samples. The corrosion resistance of the coated samples is found to be decreasing at higher concentrations of the catalyst due to the dissolution of the aluminum oxide at the substrate surface in the acid sol. However, lower concentrations of the catalyst lead to low hydrolysis reactions of the silanes and non-dense sol-gel films have been formed. The heat treatment of the coated aluminum samples is required for cross-linking of the film. The heat treatment at 300 ˚C for 2.5 hours exhibits the best corrosion protection. Higher treatment-temperatures lead to degradation of the properties of the film which can be described in terms of destroying the organic part of the film. Moreover, low treatment-temperatures cause low corrosion protection of the coated aluminum samples which is presumably attributed to the low cross-linking of the sol-gel film at temperatures less than 300 ˚C. The coated aluminum samples are characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques
Velez-Cedeno, Francisco Gerardo. "Multiple Swing Out-of-Step Relaying". Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/40394.
Texto completoPh. D.
Wiid, P. Gideon. "Lightning protection and radio frequency interference mitigation for the Karoo Array Telescope". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4009.
Texto completoENGLISH ABSTRACT: South Africa and Australia are now the two remaining countries bidding for the Square Kilometre Array (SKA), the biggest and most sensitive project ever undertaken in radio astronomy. The South African SKA is demonstrating its technology capabilities through the Karoo Array Telescope (KAT or MeerKAT). The development of KAT is taking place in stages to optimise design and minimise risks at each stage. An array of seven 12 m antennas will be complete by the end of 2009, called KAT-7. The following phase will see the construction of MeerKAT, which will lead to eighty arrayed dishes. Lightning and RFI studies for KAT-7 are the focus of this dissertation. Due to the extent and complexity of the South African demonstrator project, these studies have largely been conducted on a single structure. Parameters for the dish antenna and pedestal design changed throughout their development. To be effective, the doctoral research had to track these changes appropriately. A Method of Moments frequency domain computational electromagnetic code, FEKO, is used throughout the study. The consequences of direct and indirect lightning strikes are examined for the KAT-7 structure. Important FEKO model verification is achieved through measurement of physical scale models in an anechoic chamber. The microwave simulation code, CST, gives direct comparison of FEKO results by using a finite volume time domain method of calculation. Using frequency domain analysis on these models, the lightning down conductor design over the dish antenna bearings is optimised with cost-effectiveness as one driving parameter. RFI coupling levels for different designs are compared to each other to identify areas requiring RFI mitigation. Analysis of resonances enables evaluation of the mitigation at frequencies sensitive to radio astronomy. A Sommerfeld integral ground plane is used together with the computational model to investigate the use of the concrete foundation steel reinforcing as part of the lightning earthing electrode system. Different interconnections of the steel reinforcing elements are critically evaluated. The KAT-7 design incorporated clear lightning protection and RFI mitigation policies derived from recommendations contained within this dissertation.
AFRIKAANSE OPSOMMING: Suid-Afrika en Australie is nou die oorblywende twee lande wat bie vir die Vierkante Kilometer Reeks (SKA), die grootste en mees sensitiewe projek nog ooit in radio astronomie onderneem. Die Suid Afrikaanse SKA demonstreer sy tegnologiese bekwaamheid met die Karoo Reeks Teleskoop (KAT of MeerKAT). Die ontwikkeling van KAT vind plaas in fases om die ontwerp te optimaliseer en risikos te minimaliseer met elke fase. ’n Reeks van sewe 12 m antennas, genaamd KAT-7, sal teen die einde van 2009 klaar wees. Die volgende fase behels die konstruksie van MeerKAT, wat sal lei tot ’n tagtig-skottel reeks. Die fokus van hierdie proefskrif hanteer weerlig en radiofrekwensie steurings (RFS) vir KAT-7. As gevolg van die omvang en kompleksiteit van die Suid-Afrikaanse demonstreerder projek, is die studies hoofsaaklik op een struktuur gedoen. Parameters vir die antenna-skottel en -voetstuk ontwerp het met hul ontwikkeling deurgaans verander. Om effektief te wees, moes die doktorale navorsing hierdie veranderinge toepaslik volg. ’n Metode-van-Momente frekwensiedomein rekenaar elektromagnetiese kode, FEKO, is deurgaans met die studie gebruik. Die gevolge van direkte en indirekte weerligslae vir die KAT-7 struktuur is ondersoek. Belangrike FEKO model bevestiging is bereik met metings van skaalmodelle in ’n anego¨ıse kamer. Die mikrogolf-simulasie kode, CST, gee ’n direkte vergelyking met die FEKO resultate deur ’n eindige-volume-tyd-domein metode van berekening te gebruik. Met behulp van frekwensiedomein analise van hierdie modelle, is die weerligafleierontwerp oor die antenna-skottel laers ge-optimaliseer, met koste-effektiwiteit as een van die drywingsparameters. RFS koppelingsvlakke vir onderskeie ontwerpe is teen mekaar opgeweeg om areas te identifiseer wat RFS tempering benodig. Analise van resonansies stel die evaluering van die tempering in staat teen frekwensies wat sensitief is vir radio astronomie. ’n Sommerfeld integrale grondvlak word saam met die rekenaarmodel gebruik om die insluiting van die beton se staalversterking as deel van die aardingselektrodestelsel te ondersoek. Verskillende bindmetodes van die onderlinge staalversterkingselemente word krities ge¨evalueer. Die KAT-7 ontwerp inkorporeer duidelike weerligbeveiligings- en RFS temperingstrategie ¨e, komende van aanbevelings in hierdie proefskrif omskryf
McKillop, Jordan M. "Reducing the activation of the IRIS reactor building using the SCALE/MAVRIC methodology". Thesis, Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/37209.
Texto completoHenriquez, Gonzalez Magaly. "Etude d’un traitement multifonctionnel vert pour la protection contre la corrosion de l’acier au carbone API 5L-X65 en milieu CO2". Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0030/document.
Texto completoThe objective of this work was to evaluate the corrosion inhibitive properties of a multifunctional treatment used in the petroleum industry. In the first part of the thesis, the influence of hydrodynamic conditions, immersion time and temperature on the corrosion process of API 5L-X65 steel in CO2 medium in absence of inhibitor was studied by electrochemical measurements (polarization curves, Levich curves and electrochemical impedance spectroscopy) with a rotating disk electrode. From these tests, the corrosion rate was calculated for different experimental conditions. The analysis of the electrochemical results and surface analyses suggest the formation of a layer of corrosion products, mainly iron carbonate which covers the metal surface and leads to the decrease of the corrosion rate when the immersion time, the rotation speed and temperature increase. The second part of this work was devoted to the evaluation of a multifunctional treatment against corrosion. The treatment is mainly composed Aloe Vera extracts (Aloe Vera gel and "acibar”). These products were chosen because they prevent the simultaneous formation of hydrates and calcium carbonate. These "green" compounds and dodecylamine, which is a commercial corrosion inhibitor, were tested using electrochemical measurements and by mass loss in order to compare their efficiency and to evaluate a possible synergistic effect when they are used as a mixture. The products tested separately have a similar efficiency and did not reveal any synergistic effect. However, it was shown that the compounds are compatible. This is an important point for the use of these treatments which can increase the reliability and profitability for the production of oil and gas
Menezes, Alex Vilarindo. "A proteção de retaguarda para linhas de transmissão aplicando medição fasorial sincronizada". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-11102012-155353/.
Texto completoThe present work aims to develop a methodology for large area Electric Power System (EPS) backup protection, through a Synchronized Phasor Measurement System (SPMS). The methodology is based on continuous monitoring and on the large area EPS protection focused on transmission lines. Through backup protection algorithm implemented, grounded on the differential protection philosophy, which is based on power flow inversion detection, detects the faulty transmission line through the remotely acquired voltage and current data by SPMS. The simulations in SEP discussed all the possibilities of single phase, two phase and three phase short-circuits, with and without the involvement of the ground, varying the fault incidence angle and resistance within a range of values commonly presented in real situation. The results found in this research show the efficiency of the proposed methodology, achieving the protection system primary requirements (speed, reliability, selectivity and sensitivity). In this context, it is concluded that it is feasible the proposed methodology application on the EPS backup protection characterized by a large coverage area, fulfilling the purposes of a digital protection system, since be available a reliable and fast communication infrastructure for the needed data traffic.
Oliveira, Aurélien. "Conception et développement de capteurs et vêtements intelligents pour le suivi et la protection des pompiers : mesures thermiques non-invasives ambulatoires". Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00677778.
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