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 76 for “"direct current (DC)"”.
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Hardware model of a shipboard Zonal Electrical Distribution System (ZEDS) Alternating Current/Direct Current (AC/DC)
… IIA, Arleigh Burke class, 60Hz Alternating Current (AC) and the future direct current (DC), zonal electrical distribution system (ZEDS). These distribution boards were designed and built for the purpose of testing electrical system components at the Massachusetts Institute of Technology's …
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Astrochemical dynamics: Fundamental studies relevant to titan's atmosphere
… CH3CH2NH2+ radical cation at 233.3 nm using Direct current (DC) slice imaging technique, revealing important features of the potential surface that are important in Titan's ion-molecule reactions. Finally, a new technique is implemented to measure the branching ratios for the reactions of …
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Modulation of the Magnetic Properties of Aqueous Metal Ions and the Bioelectrodynamic Effects on Cancerous and Noncancerous Cells
… behavior of aqueous metal ions by applying direct current (DC) with a Lorenz force to a hypotonic saline solution. This treated solution was then used to make growth media for cancerous and noncancerous cell lines in vitro. Exposure of cancerous and noncancerous cells to this media showed …
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Electrohydrodynamic Simulations of the Deformation of Liquid-Filled Capsules
… deformable capsules is provided. The role of a direct current (DC) electric field on the deformation and orientation of a liquid-filled capsule is thoroughly considered numerically. This framework is based on lattice Boltzmann method for the fluid, finite element method for the membrane …
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Improving performance, efficiency, and reliability of DC-DC conversion systems by differential power processing
Direct current (dc) systems are found in a broad range of devices including computer microprocessors, battery packs, and solar photovoltaic (PV) arrays. Operating the energy conversion systems in these devices with high efficiency, performance, and reliability is important. This dissertation …
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A low dispersion 2-GHz comparator
… computer (PC), digital signal processing (DSP), direct current (DC), alternating current (AC), device under test (DUT), pin electronics (PE), bipolar junction transistors (BJT), complementary metal oxide semiconductor field effect transistor (MOSFET).
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BEAMED: A Bench for Automated Measurements of Electrical Discharges - A New Standard for Paschen Curves
… studies and applications of Paschen's law, current methodologies for experimental Paschen tests in direct current (DC) conditions lack standardized practices. This thesis presents the development and validation of a DC-based standard for electrical discharge initiation, using the BEnch for …
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Technologya nd Protocolsf or Translational Researchin ElectricalS timulation
… stimulation techniques like transcranial direct currents stimulation (tDCS) have been demonstrated to modulate neural function. Weak constant current is applied via scalp electrodes leading to subthreshold changes in neuron membrane potentials. Neuromodulation of the cortex using direct …
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Geophysical Investigation of the Yellowstone Hydrothermal System
… Transient electromagnetic (TEM) soundings and 2D direct current (DC) resistivity profiles show that hydrothermal alteration at active sites have a higher electrical conductivity than the surrounding hydrothermally inactive areas. For that reason, airborne TEM is an effective method to characterize …
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Analysis of an energy efficient permanent magnet brushless universal motor
… of a PM synchronous and a PM brushless direct current (DC) motor. The PM universal motor has the capability to operate as a variable speed DC shunt motor with high torque at low speeds, and also as a synchronous motor at constant speed with high efficiency. The literature on synchronous …
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Creating a shipboard power simulation tool using electrical load behavior modeling
… expand its modeling capability so it can support direct current (DC) electrical distribution systems. The SPS, in its current form can only model alternating (AC) electrical distribution systems.
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Mathematical Modelling of Grid Connected Fixed- Pitch Variable-Speed Permanent Magnet Synchronous Generators for Wind Turbines
… circuit. The boost chopper circuit offers a direct current (DC) power supply with constant voltage for the inverter. Sampled signals of instantaneous 3-phase voltage (from the power grid) to obtain the phase angle, frequency and amplitude, are used to generate SVPWM signals to control the …
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Electro-Mechanical Design and Testing of a Prototype Low-Cost Rheometer
… fluid. The first prototype used an encoded direct current (DC) motor to rotate at a constant rate while measuring the motor current draw to estimate torque and was able to measure a fluid viscosity standard with η = 100 Pa.s within 17% of the known value. The second prototype used a …
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Digital speed and position control system incorporating an Incremental encoder
Nowaday Direct current (DC) motor become an important drive configuration for many applications across a wide range of powers and speeds. The ease of control and excellent performance of the DC motors will ensure that the number of applications using them will continue grow for the foreseeable …
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Radiation response and optical characterization of carbon based thin-films prepared by saddle field plasma enhanced chemical vapor deposition
… for different detection applications. In the current study, the direct current (DC) saddle field Plasma Enhanced Chemical Vapor Deposition (PECVD) method was used to prepare a set of nano-crystalline diamond samples. The relation between the deposition pressure, the gases mixing ratios and the …
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Electrochemical Synthesis of Soft Magnetic Alloys and Laminates for High Frequency Field Application
… laminate and bulk alloys. Using a combination of direct current (DC) and pulse current deposition methods, multilayered magnetic structures are produced from a single bath chemistry containing pyrrole monomer, phosphorus additive, or a combination of both. The resulting inductor cores consist of …
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An Experimental Investigation of Electrowetting Modulated Nucleate Boiling
… surfaces, and examine the effects of both direct current (DC) EW and alternating current (AC) EW on the overall boiling heat transfer characteristics. A synchronized high-speed optical imaging and infrared thermography approach is taken to obtain simultaneous measurements of the bubble …
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Hardware model of a shipboard zonal electrical distribution system (ZEDS) : alternating current/direct current (AC/DC)
… IIA, Arleigh Burke class, 60Hz Alternating Current (AC) and the future direct current (DC), zonal electrical distribution system (ZEDS). These distribution boards were designed and built for the purpose of testing electrical system components at the Massachusetts Institute of Technology's …
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Electrokinetic-assisted phytoremediation of heavy metal in riverbank soil
… system (a pair of EK electrodes connected to a direct current (DC) power supply with a magnitude of 6 V/cm-1 electric field) for 4 hours/day. The soil and plant samples from pre and post treatments were analyzed using and X-ray Fluorescence Spectrometer (XRF), Scanning Electron Microscope / …
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Fabrication and Characterization of Titanium-doped Hydroxyapatite Thin Films
… bone mineral, HA promotes growth of bone tissue directly on its surface. Substitution of other elements has shown the potential to improve the bioactivity of HA. Magnetron co-sputtering is a physical vapour deposition technique which can be used to create thin coatings with controlled levels of a …
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