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13
May 24, 2022
05/22
by
Stoll, Richard L
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xii, 128 p. 24 cm
Topic: Eddy currents (Electric)
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34
Jul 15, 2019
07/19
by
Lammeraner, Jiří
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233 p. 22 cm
Topic: Eddy currents (Electric)
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78
Oct 8, 2015
10/15
by
Buch, Eric J
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Thesis advisor, Mary L. Batteen
Topic: OCEAN MODELS,EDDY CURRENTS
Thesis advisor, Mary L. Batteen
Topics: OCEAN MODELS, EDDY CURRENTS
Inaug.-dis.--Karlstruhe
Topics: Armatures, Eddy currents (Electric)
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15
Aug 13, 2020
08/20
by
Libby, Hugo L
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xiv, 365 pages 24 cm
Topics: Nondestructive testing, Eddy currents testing, Eddy currents (Electric), Zerstörungsfreie...
253
253
May 27, 2011
05/11
by
Walker, Sandra P
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Testing of composite sandwich joint elements has been completed to verify the strength capacity of joints designed to carry specified running loads representative of a high speed civil transport wing. Static tension testing at both room and an elevated temperature of 350 F and fatigue testing at room temperature were conducted to determine strength capacity, fatigue life, and failure modes. Static tension test results yielded failure loads above the design loads for the room temperature tests,...
Topics: EDDY CURRENTS, ECCENTRICITY, HOLES (MECHANICS), IMPEDANCE, CALIBRATING, DEFECTS, SCANNERS
Our long-term goal is to perform an eddy-resolving global ocean simulation using the Parallel Ocean Program (POP) that will provide a high fidelity ocean model state for use as an initial condition in a global ocean/atmosphere/ice prediction system. In addition, the global model state may be used to specify boundary conditions for regional circulation models.
Topics: DTIC Archive, LOS ALAMOS NATIONAL LAB NM, *OCEAN MODELS, EDDY CURRENTS
Journal of Research of the National Bureau of Standards
Topics: boundary integral equations, crack detection, eddy currents, electromagnetic NDE, nondestructive...
The long-term goal of this project is to improve understanding and predictability of the regional circulation in the western North Pacific.
Topics: DTIC Archive, WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *EDDY CURRENTS, NORTH PACIFIC OCEAN,...
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223
Jun 26, 2010
06/10
by
NON
texts
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Cosmic gamma ray energy spectra caused by hyperon and nucleon isobar decays for gamma ray energies above 1 GeV, and differential production cross section
Topics: DIRECTIONAL ANTENNAS, MECHANICAL DRIVES, PARABOLIC ANTENNAS, EDDY CURRENTS, ERROR SIGNALS, RADIO...
This paper reports the experimental measurement and imaging of the acoustic fields generated by low-frequency eddy currents in metals in the absence of an external static magnetic field using a modified atomic force microscope. Acoustic displacements in a typical metal placed in eddy current field without static magnetic field were theoretically computed and found to be in the range of few hundred picometers. A modified atomic force microscope was used to detect and measure the acoustic...
Topics: DTIC Archive, DAYTON UNIV RESEARCH INST OH, *ACOUSTIC FIELDS, EDDY CURRENTS, MEASUREMENT, METALS,...
System can be utilized in flight or at flight line. It monitors disk rim for surface cracks emanating from blade root interface. System consists of eddy-current sensor, mounted approximately 1 1/2 mm (1/16 in) away from face of disk, and remotely located electrical capacitance-conductance bridge and signal analyzer.
Topics: NASA Technical Reports Server (NTRS), EDDY CURRENTS, SURFACE CRACKS, TURBINE WHEELS, Barranger, J....
162
162
May 31, 2011
05/11
by
Guruswamy, Guru P
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A modular process that can efficiently solve large scale multidisciplinary problems using massively parallel supercomputers is presented. The process integrates disciplines with diverse physical characteristics by retaining the efficiency of individual disciplines. Computational domain independence of individual disciplines is maintained using a meta programming approach. The process integrates disciplines without affecting the combined performance. Results are demonstrated for large scale...
Topics: FRICTION WELDING, NONDESTRUCTIVE TESTS, WELDED JOINTS, ALUMINUM ALLOYS, AEROSPACE ENGINEERING, EDDY...
The process of manufacturing laminated TERFENOL-D is costly and time consuming. This Phase I study was aimed at reducing the reject rate of the current lamination process and thus reducing the cost of laminated TERFENOL-D. Current stringent requirements call for infinite resistance between lamina. These requirements can lead to reject rates as high as 50%. Analytical calculations indicate that somewhat less than infinite interlaminate resistance is needed for eddy current reduction. This...
Topics: DTIC Archive, Slaughter, Julie, ETREMA PRODUCTS INC AMES IA, *LAMINATES, TEST METHODS, SONAR, EDDY...
The long-term goal of this project is to improve understanding and predictability of the regional circulation in the western North Pacific. The objective of this project is to characterize variability in the Kuroshio east of Taiwan and to understand (1) how this variability is related to variability in the upstream region, where the North Equatorial Current bifurcates forming the northward-flowing Kuroshio and the southward-flowing Mindanao Current and (2) how westward-propagating mesoscale...
Topics: DTIC Archive, WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *EDDY CURRENTS, *NORTH PACIFIC OCEAN,...
5,849
5.8K
May 22, 2011
05/11
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NON
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Proceedings from symposia of the Technology 2003 Conference and Exposition, December 7-9, 1993, Anaheim, CA, was discussed. Volume 1 features the Plenary Session and the Plenary Workshop, plus papers presented in Advanced Manufacturing, Biotechnology/Medical Technology, Environmental Technology, Materials Science, and Power and Energy.
Topics: CRACK TIPS, CRACKS, DEFECTS, EDDY CURRENTS, ELECTROMAGNETIC SHIELDING, FERROMAGNETIC MATERIALS,...
The need to accurately model multiscale phenomena is ubiquitous in eddy-current nondestructive evaluation. By using volume-integral equations, we are able to develop a very simple algorithm for accurately computing the response of a very small anomaly in the presence of a much larger one. We validate the algorithm and its associated code in VIC-3D(copyright) through benchmark data on two test sets: (1) a notch at a bolt hole with an upper surface coil, and (2) a notch in a bolt hole with a...
Topics: DTIC Archive, VICTOR TECHNOLOGIES LLC BLOOMINGTON IN, *EDDY CURRENTS, *NONDESTRUCTIVE TESTING,...
Large-eddy simulation (LES) has been plagued by an inability to predict the law-of-the-wall (LOTW) in mean velocity in the surface layer at high Reynolds numbers. Brasseur & Wei developed a theory that explains the source of the difficulty and a framework within which LES can be designed to rectify the problem. The essential difficulty lies in nonphysical frictional content within the discretized dynamical system and the extent to which that frictional content interferes with the inertial...
Topics: DTIC Archive, PENNSYLVANIA STATE UNIV STATE COLLEGE, *EDDY CURRENTS, BOUNDARY LAYER, LOGARITHM...
Non destructive testing methods are often used in order to detect and classify structural flaws. The detection of structural flaws is useful for maintenance. In this paper we propose to classify flaws in ferromagnetic materials by measuring Eddy currents. Our approach consists of two steps. First, we use a system identification algorithm to find a dynamical system which describes the data. Then, we use the parameters of this dynamical system as a feature vector and we use support vector...
Topics: DTIC Archive, Guepie,Blaise, Mines Douai, IA Douai France, eddy currents, feature extraction,...
The focus of modeling in this study is to quantify relationships between surface fluxes of heat, energy and momentum, the available baroclinic potential energy, the resultant vertical mixing and geostrophic imbalance, and the ensuing dependence of lateral mixing at successively larger scales on atmospheric forcing.
Topics: DTIC Archive, WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB, *TURBULENCE, ENERGY, EDDY CURRENTS, HEAT...
Precision holes are among the most critical features of a mechanical component. Deviations from permissible tolerances can impede operation and result in unexpected failure. We have developed an automated non-contact eddy current hole diameter and eccentricity measuring system. The operating principle is based on the eddy current lift-off effect, which is the coil impedance as a function of the distance between the coil and the test object. An absolute eddy current probe rotates in the hole....
Topics: NASA Technical Reports Server (NTRS), EDDY CURRENTS, ECCENTRICITY, HOLES (MECHANICS), IMPEDANCE,...
The design and fabrication of conventional and unconventionally processed Ti-Nb base and Al5-compound-base, respectively, composite superconductors is discussed in a nine section review. The first two sections introduce the general properties of alloy and compound superconductors, and the design and processing requirements for the production of long lengths of stable low loss conductor. All aspects of flux jump stability, and the general requirements of cryogenic stabilization are addressed....
Topics: NASA Technical Reports Server (NTRS), CRYOGENICS, DESIGN ANALYSIS, SUPERCONDUCTORS (MATERIALS),...
1,401
1.4K
May 31, 2011
05/11
by
Siddiqi, Asif A
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This monograph contains brief descriptions of all robotic deep space missions attempted since the opening of the space age in 1957. The missions are listed strictly chronologically in order of launch date (not by planetary encounter).
Topics: NONDESTRUCTIVE TESTS, ROCKET ENGINES, REUSABLE LAUNCH VEHICLES, AUTOMATION, METALS, SPACECRAFT...
This is an interdisciplinary conference. Topics are related to fundamental aspects of Turbulence Physics and include the following fields: Instabilities and transition; Experimental techniques; Direct Numerical Simulation/Large Eddy Simulation; Compressible turbulence; Transport and mixing; Geophysical and environmental flows; Vortex dynamics; Intermittence and scaling; and Turbulent reacting flows.
Topics: DTIC Archive, Dopazo, C, ZARAGOZA UNIV (SPAIN), *TURBULENT FLOW, SIMULATION, SYMPOSIA, VORTICES,...
This paper presents a five-year global simulation of HYCOM, the HYbrid Coordinate Ocean Model, that simultaneously resolves the eddying general circulation, barotropic tides, and baroclinic tides with 32 layers in the vertical direction and 1/12.5 (equatorial) horizontal grid spacing. A parameterized topographic wave drag is inserted into the model and tuned so that the surface tidal elevations are of comparable accuracy to those in optimally tuned forward tide models used in previous studies....
Topics: DTIC Archive, NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV, *OCEAN MODELS, REPRINTS,...
A non-inertial sensing approach for an Acoustic Vector Sensor (AVS), which utilizes eddy-current displacement sensors and operates well at Ultra-Low Frequencies (ULF), is described here. In the past most ULF measurements (from mHertz to approximately 10 Hertz) have been conducted using heavy geophones or seismometers that must be installed on the seafloor; these sensors are not suitable for water column measurements. Currently, there are no readily available compact and affordable underwater...
Topics: DTIC Archive, NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI, *ACOUSTIC DETECTORS, *INFRASOUND, EDDY...
Research during the fouth year of this project has focused on extending the analysis of baroclinic instability and performing a mixed layer experiment to examine dye dispersion.
Topics: DTIC Archive, OREGON STATE UNIV CORVALLIS, *EDDY CURRENTS, *MICROBAROMETRIC WAVES, *TURBULENT FLOW,...
The general circulation of the global ocean is turbulent rather than laminar. Mesoscale eddies contribute to the transport of tracers like heat, salt, and oxygen, and affect large-scale ocean dynamics. The problem of representing mesoscale variability stems from the nonlinear character of eddy dynamics that makes it difficult to predict equilibrated fluxes. The most intuitive solution is to apply a parameterization based on the eddy-driven transport observed in a global ocean that has been...
Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *OCEAN CURRENTS, ACOUSTIC SIGNATURES, EDDY...
Examination of the reliability test data from the eddy current Retirement For Cause (RFC) systems installed at the-San Antonio and Oklahoma City ALCs has revealed occasional systematic shifts in the probability of detection (POD) curves created from inspecting specimens containing fatigue cracks. Analysis showed that the shift was not related to the fatigue cracks. The most likely cause was thought to be the gain calibration process uses electro-discharge machined (EDM) notches as the artifact...
Topics: DTIC Archive, Stubbs, David A, DAYTON UNIV OH RESEARCH INST, *INSPECTION, CRACKS,...
Principles and applications of nondestructive tests
Topics: NASA Technical Reports Server (NTRS), NONDESTRUCTIVE TESTS, TECHNOLOGY UTILIZATION, DEFECTS, EDDY...
Our long term technical goal is to produce a tested adjoint for ROMS (the Regional Ocean Modeling System, descended from SCRUM) that is suitable for general use by ROMS modelers. This is complementary to the Kalman Filter, ESSE, and Singular Vector techniques being developed by Rutgers, Harvard and University of Colorado scientists. Our long-term scientific goal is to model and predict the mesoscale circulation and the ecosystem response to physical forcing in the California Current System...
Topics: DTIC Archive, SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA, *EQUATIONS, *FORECASTING, *OCEAN...
We have studied the feasibility of using High Temperature Superconducting levitation bearings for Flywheels and momentum wheels in energy and momentum storage for space applications. We have constructed a small flywheel prototype to demonstrate the principle. Measurement of small residual losses in HTS levitation bearings so as to be able to optimize design parameters to keep the losses to the lowest possible. There are two distinct loss mechanisms: magnetic hysteresis in HTS, or eddy currents...
Topics: DTIC Archive, Chu, Wei-Kan, TEXAS CENTER FOR SUPERCONDUCTIVITY HOUSTON, *HIGH TEMPERATURE...
Spatial and temporal variability of the Black Sea surface circulation with the link to chlorophyll-a concentration and surface winds is investigated using Satellite data from Archiving, Validation, and Interpretation of Satellite Oceanographic data (AVISO), Sea-viewing Wide Field-of-view Sensor (SeaWiFS), and Quick Scatterometer (QuikSCAT) with the Self-Organizing Maps (SOMs). Six spatial patterns with temporal variability were identified for the surface currents: Pattern-1 (Sevastopol Cyclonic...
Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *OCEANOGRAPHIC DATA, BLACK SEA, CHLOROPHYLLS,...
Synoptic maps for 28-29 August 2002 indicate typical near-surface northerly flow along coastal California, while Goes-10 animated satellite imagery from this period show a stratuscapped, coastally trapped disturbance (CTD) propagating northward against the prevailing flow. A pronounced hydraulic-jump-like (shock) feature develops in the cloud field south of Cape Mendocino (CM) and angles linearly away from the coast. Over the next 6 hours both the CTD and the shock feature move northward and,...
Topics: DTIC Archive, NAVAL RESEARCH LAB MONTEREY CA, *SHOCK, *EDDY CURRENTS, *COASTAL REGIONS, SYNOPTIC...
Motivated by the potential of oceanic mesoscale eddies to drive intrinsic low-frequency variability, this paper examines geostrophic turbulence in the frequency wavenumber domain. Frequency wavenumber spectra, spectral fluxes, and spectral transfers are computed from an idealized two-layer quasigeostrophic (QG) turbulence model, a realistic high-resolution global ocean general circulation model, and gridded satellite altimeter products. In the idealized QG model, energy in low wavenumbers,...
Topics: DTIC Archive, NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV,...
The vast majority of all operational railguns in the world employ a metallic containment housing. Often composed of thousands of precision sheet metal laminates to prevent induced eddy currents, the launchers are labor intensive to build. The backbone railgun provides a monolithic metallic containment structure. Induced eddy currents are inhibited by the introduction of a large number of slits along the length of the launcher that achieve an effect analogous to traditional laminates. It is...
Topics: DTIC Archive, ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS,...
The goal of this research project is to develop improved capabilities for classifying buried objects as unexploded ordnance (UXO) or clutter that exploit all of the information available in the electromagnetic induction (EMI) response of the object. There are two basic components in the EMI response: magnetization of the object by the primary field and the evolution of eddy currents set up in the object by changes in the primary field. The first is accessible only with sensors which measure the...
Topics: DTIC Archive, SCIENCE APPLICATIONS INTERNATIONAL CORP MCLEAN VA, *ELECTROMAGNETIC INDUCTION, BURIED...
In eddy current non-destructive testing of a multi-layered riveted structure, rotating current excitation, generated by orthogonal coils, is advantageous in providing sensitivity to defects of all orientations. However, when used with linear array sensors, the exciting magnetic flux density (Bx) of the orthogonal coils is not uniform over the sensor region, resulting in an output signal magnitude that depends on the relative location of the defect to the sensor array. In this paper, the...
Topics: DTIC Archive, Ye,Chaofeng, MICHIGAN STATE UNIV EAST LANSING EAST LANSING United States, eddy...
Non destructive testing methods are often used in order to detect and classify structural flaws. The detection of structural flaws is useful for maintenance. In this paper we propose to classify flaws in ferromagnetic materials by measuring Eddy currents. Our approach consists of two steps. First, we use a system identification algorithm to find a dynamical system which describes the data. Then, we use the parameters of this dynamical system as a feature vector and we use support vector...
Topics: DTIC Archive, Guepie,Blaise, Mines Douai, IA Douai France, NONDESTRUCTIVE TESTING, FERROELECTRIC...
This process specification establishes the minimum requirements for eddy current inspection of flat surfaces, fastener holes, threaded fasteners and seamless and welded tubular products made from nonmagnetic alloys such as aluminum and stainless steel.
Topics: NASA Technical Reports Server (NTRS), EDDY CURRENTS, ALUMINUM, STAINLESS STEELS, INSPECTION, FLAT...
Two eddy current proximity probe systems were tested over a range of 0 to 508 micrometers (0 to 20 mils) of simulated potassium film thicknesses for simulated temperatures of 66 C (150 F), 232 C (450 F), and 666 C (1230 F). The results of short time calibration tests are presented. Instrument drift was a problem throughout the testing and, without correction, may limit the use of such systems to short periods of time. Additional development will be required prior to their being usable as...
Topics: NASA Technical Reports Server (NTRS), DRIFT (INSTRUMENTATION), EDDY CURRENTS, INSTRUMENT...
This report describes developments in magneto-Optic imaging that make possible practical real-time imaging of surface corrosion under protective coatings in both steel and aluminum. The technology can also be applied to the detection of cracks. To accomplish imaging in steel a new method for producing rotating in-plane magnetization in steel parts was developed and combined with real-time magneto-optic imaging. Imaging in aluminum is accomplished by using an eddy-current excitation device for...
Topics: DTIC Archive, Fitzpatrick, Gerald, PHYSICAL RESEARCH INC KIRKLAND WA, *MAGNETOOPTICS, CORROSION,...
This paper uses eddy current based techniques and reduced order modeling to explore the feasibility of detecting a subsurface damage in structures such as air foils and pipelines. To identify the geometry of a damage, an optimization algorithm is employed which requires solving the forward problem numerous times. To implement these methods in a practical setting, the forward algorithm must be solved with extremely fast and accurate solution methods. Therefore, our computational methods are...
Topics: DTIC Archive, Joyner, Michele L, INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING...
Impacts of ocean heat content (OHC) and vertical wind shear on intensity changes of Typhoon Sinlaku and Typhoon Jangmi during the Tropical Cyclone Structure-2008 and THORPEX Pacific Asian Regional Campaign are investigated. Observations of ocean structure variables were obtained in the environment of each typhoon via aircraft-deployed expendable bathythermographs (AXBTs). Strong correspondence among storm intensity changes, ocean features, and vertical wind shear is identified as each tropical...
Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *TROPICAL CYCLONES, THESES, WEATHER...
This report analyzes the eddy current induced in a solid conducting sphere by a sinusoidal current in a circular loop. Analytical expressions for the eddy currents are derived as a power series in the vectorial displacement of the center of the sphere from the axis of the loop. These are used for first order calculations of the power dissipated in the sphere and the force and torque exerted on the sphere by the electromagnetic field of the loop.
Topics: NASA Technical Reports Server (NTRS), CONDUCTORS, EDDY CURRENTS, ELECTROMAGNETIC FIELDS, SPHERES,...
This report presents some recent developments in the mathematical modeling of the Large Angle Magnetic Suspension Test Fixture (LAMSTF) at NASA Langley Research Center. It is shown that these effects are significant, but may be amenable to analysis, modeling and measurement. A theoretical framework is presented, together with a comparison of computed and experimental data.
Topics: NASA Technical Reports Server (NTRS), EDDY CURRENTS, ELECTROMAGNETS, MAGNETIC SUSPENSION,...
Under the Aircraft Structural Integrity program, Langley Research Center invented a device to detect fatigue cracks in aluminum alloy plates. Krautkramer Branson obtained an exclusive license and commercialized a hand-held device, the "CrackFinder," an electromagnetic probe for nondestructive evaluation, used to scan aircraft skins for surface breaks. The technology involves an eddy current, which is an electrical current induced by an alternating magnetic field. The CrackFinder also...
Topics: NASA Technical Reports Server (NTRS), TECHNOLOGY UTILIZATION, NONDESTRUCTIVE TESTS, AIRCRAFT...
While parametric uncertainty quantification for NDE models has been addressed in recent years, the problem of stochastic field parameters such as spatially distributed electrical conductivity has only been investigated minimally in the last year. In that work, the authors treated the field as a one-dimensional random process and Karhunen-Loeve methods were used to discretize this process to make it amenable to UQ methods such as ANOVA expansions. In the present work, we will treat the field as...
Topics: DTIC Archive, DAYTON UNIV RESEARCH INST OH, *EDDY CURRENTS, ANISOTROPY, CORRELATION, ELECTRICAL...
As part of the health assessment of flight spare 40in diameter Kevlar composite overwrapped pressure vessels (COPVs) SN002 and SN027 an eddy current characterization of the composite and liner thickness change during pressurization was requested under WSTF-TP-1085-07.A, "Space Shuttle Orbiter Main Propulsion System P/N MC282-0082-0101 S/N 002 and Orbital Maneuvering System P/N MC282-0082-001 S/N 027 COPV Health Assessment." The through the thickness strains have been determined to be...
Topics: NASA Technical Reports Server (NTRS), EDDY CURRENTS, COMPOSITE WRAPPING, PRESSURE VESSELS, KEVLAR...
