Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 237 for “"relays"”.
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Spaceborne centrifugal relays for spacecraft propulsion
Acceleration using centrifugal relays is a recently discovered method for the acceleration of spaceborne payloads to high velocity at high thrust. Centrifugal relays are moving rotors which progressively accelerate reaction mass to higher velocities. One important engineering problem consists of …
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Relays for Interference Mitigation in Wireless Networks
… in the network. Conventionally, the role of such relays is limited to passing messages in a chain in a point-point hopping architecture. With the decentralization, multiple nodes could potentially interfere with each other. This work proposes a technique to exploit the presence of relays in a way …
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Carbon nano-relays for low power switching
… nanoelectromechanical switches or carbon nano-relays are demonstrated as a toolkit for investigating NEMs based low power switching. The first is a vertical carbon nano-relay, consisting of a vertically aligned carbon nanotube/fiber (CN) between two contacts and operated by pull-off, and the …
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COMPUTER MODELLING OF DIGITAL DISTANCE AND DIRECTIONAL RELAYS
… the use of micro-processor based relays for power system protection has received much attention from power system researchers. To develop micro-processor relays suitable for use in power systems, their performance must be evaluated during the design stage. For achieving this, two …
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Hidden Failure in Protective Relays: Supervision and Control
… RSS, along with simplified models of existing relays, performed in Matlab. A power system model in EMTP provides inputs to the RSS model. Multiple faults are applied to the EMTP model, and the RSS is tested under each fault condition, and with a variety of relay hidden failures. For all tests …
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Use of transportation relays to improve private fleet management
We explore the use of transportation relays, a somewhat unconventional transportation operations concept, in terms of improving private fleet management. A transportation relay is a shipment that is divided into two legs. With transportation relays, there is more ways to route freight with a …
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Progressively communicating rich telemetry from autonomous underwater vehicles via relays
As analysis of imagery and environmental data plays a greater role in mission construction and execution, there is an increasing need for autonomous marine vehicles to transmit this data to the surface. Without access to the data acquired by a vehicle, surface operators cannot fully understand the …
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Progressively communicating rich telemetry from autonomous underwater vehicles via relays
As analysis of imagery and environmental data plays a greater role in mission construction and execution, there is an increasing need for autonomous marine vehicles to transmit this data to the surface. Without access to the data acquired by a vehicle, surface operators cannot fully understand the …
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Floating-point unit (FPU) designs with nano-electromechanical (NEM) relays
Nano-electromechanical (NEM) relays are an alternative to CMOS transistors as the fabric of digital circuits. Circuits with NEM relays offer energy-efficiency benefits over CMOS since they have zero leakage power and are strategically designed to maintain throughput that is competitive with CMOS …
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On the capacity of relay networks with finite memory relays
(cont.) the length of relay memory and the number of relay stages.
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BEHAVIOR OF BUSBAR DIFFERENTIAL RELAYS WITH AIR-GAP CORE CURRENT TRANSFORMERS
Protective relays normally estimate the magnitude and phase angle of current. Since the level of current is normally too high to permit a direct connection to the power system, a Current Transformer (CT) is used to scale down the current value. A CT should faithfully replicate waveform of the …
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Analyzing voltage sag direction using protective relays and deep-learning methods
… and the location of the fault. Traditional relays effectively locate, detect, and isolate faults. Circuit breakers, fuses, and relays, these devices work together to ensure the power system remains stable and reliable, under various conditions including system failures. Smart Intelligent …
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Design and fabrication of electromagnetic micro-relays using the UV-LIGA technique
… for fabricating microelectromechanical power relays. Fabrication of the device required significant advances in the optical lithography of SU-8 negative photoresist. Research proved that aspect-ratios up to 40:1 in isolated open field structures of thickness between 1 and 1.5 mm can be …
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Quantum dot-based Entangled-Light Emitting Diodes (E-LED) for quantum relays
Sources of entangled pairs of photons can be used for encoding signals in quantum-encrypted communications, allowing a sender, Alice, and a receiver, Bob, to exchange keys without the possibility of eavesdropping. In fact, any quantum information system would require single and entangled photons to …
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MEMS relays for make-break power switching applications : {111} silicon etched planar electrical contacts
Relays and switches are of interest in applications such as test equipment, radar, communications, and power systems, amongst others. Unlike solid state switches, mechanical relays provide galvanic isolation across the power ports. This characteristic is important because, for safety reasons, …
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The effect of voltage wave form on the operation of two types of current overload relays
… The effect of the wave distortion on other relays requires more study.
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Improvement of Ground-Fault Relaying Selectivity through the Application of Directional Relays to High-Voltage Longwall Mining Systems
… the ground current sensed by the ground-fault relays in unfaulted circuits is greater than the mandated ground-fault relay pick-up setting. Simulations show that ground-fault relaying selectivity is potentially lost as a result of this situation. Two alternatives were identified which could …
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Application of IEC61850 protocol to implement peer-to-peer communication on General Electric (GE) relays : evaluation of IEC61850 performance
… to be faster than hardwired contacts on the relays. The objective of this research is to prove whether the GOOSE messages are indeed faster than the hardwired contacts. The main questions that guide the thesis are, firstly, is the speed of GOOSE messages always faster than the speed of hard …
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A study of the effect of harmonics in the system on the performance of residual current-operated circuit-breakers and electromechanical overcurrent relays
… Consequently, RCCBs as well as other protection relays are subject to non-sinusoidal current waveforms. Recent studies showed that RCCBs are greatly affected by harmonics, however the reasons for this are not clear. A literature search has also shown that there are inconsistencies in the analysis …
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Recommended protection scheme setting coordination for nine busbars transmission grid
… for different protection zones of the distance relays, some problems have been raised (overlap and under reach). These problems cause improper trips in the network. The aims at overcoming the problems are by taking into consideration the specifications of the adjacent transmission lines, the …
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