465 Matching Results

Search Results

Advanced search parameters have been applied.

Resonant excitation of coupled Rayleigh waves in a short and narrow fluid channel clad between two identical metal plates

Description: This article studies the transmission of ultrasonic waves through a slit between two water immersed brass plates for sub-wavelength plate thicknesses and slit apertures.
Date: July 14, 2014
Creator: Garcia-Chocano, Victor M.; Lopez-Rios, Tomas; Krokhin, Arkadii A. & Sanchez-Dehesa, Jose
Partner: UNT College of Arts and Sciences

Review of High Level Waste Tanks Ultrasonic Inspection Data

Description: A review of the data collected during ultrasonic inspection of the Type I high level waste tanks has been completed. The data was analyzed for relevance to the possibility of vapor space corrosion and liquid/air interface corrosion. The review of the Type I tank UT inspection data has confirmed that the vapor space general corrosion is not an unusually aggressive phenomena and correlates well with predicted corrosion rates for steel exposed to bulk solution. The corrosion rates are seen to decrease with time as expected. The review of the temperature data did not reveal any obvious correlations between high temperatures and the occurrences of leaks. The complex nature of temperature-humidity interaction, particularly with respect to vapor corrosion requires further understanding to infer any correlation. The review of the waste level data also did not reveal any obvious correlations.
Date: March 9, 2006
Creator: Wiersma, B
Partner: UNT Libraries Government Documents Department

{open_quotes}Bubble fusion{close_quotes}: Preliminary estimates of spherical micro-implosions in cavitating liquids

Description: Liquids irradiated with intense ultrasonic waves can generate small cavities or bubbles. Upon nonlinear expansion to a state of disequilibrium, wherein the externally imposed hydrostatic pressure far exceeds that of entrapped non-condensable gas, these bubbles undergo a rapid and violent collapse. This collapse, if symmetric, can generate high pressures and temperatures through a number of possible mechanisms. The simplest and oldest explanation suggests a focusing of the kinetic energy of all the surrounding liquid onto the collapsing bubble and the subsequent heating of entrapped gases under either adiabatic or isothermal conditions. Although induced by externally imposed millisecond pressure oscillations, these collapses can occur on sub-microsecond timescales and are accompanied by picosecond light emissions; this combination of sound and light is called sonoluminescence. Recent explanations of observed high temperatures and picosecond radiation pulses accompanying such collapses are based on the interaction of multiple shock waves that are launched off the inward cavity wall. Other potential explanations invoke dipole emissions induced by intermolecular collisions or the release of Casimir energy when a dielectric hole is filled. Conjectures have been made that the processes responsible for sonoluminescence may be extended to generated conditions where thermonuclear fusion might occur. Such an achievement would extend scientific interest in sonoluminescence out of a purely chemical context to include the study of matter subjected to more extreme conditions. The main goal of this {open_quotes}scoping{close_quotes} study is to understand better conditions where deuterium-tritium fusion might be observed in conjunction with micro-implosions in cavitating liquids; prognoses of fusion application at this point are unintended.
Date: February 1, 1995
Creator: Krakowski, R.A.
Partner: UNT Libraries Government Documents Department

Ultrasonic Characterization of Potting Voids (An interim report)

Description: This interim report summarizes the efforts to date to develop an ultrasonic technique for detecting and sizing potting voids between a high explosive material and a metallic baclung. This report presents the results for two tasks. The first task was to establish that ultrasonic energy penetrates LX-17. Then once the acoustic properties of LX-17 were measured, a demonstration experiment substantiated that voids could be detected and imaged.
Date: April 23, 2001
Creator: Quarry, M & Thomas, G
Partner: UNT Libraries Government Documents Department

Development of a Multi-Layer Guided Wave Inspection Technique

Description: This study investigates the inspection of a particular layer of a multi-layer structure using ultrasonic guided waves. Techniques based on Lamb waves have been developed for the inspection of plate structures and are well understood. Guided waves also exist in multi-layered plates as well. Energy distributions vary across the thickness of a multi-layer structure depending on the mode and frequency. Hence, a potential way to inspect the bottom layer of a structure is to find modes with sufficient energy in the bottom layer.
Date: March 12, 2001
Creator: Quarry, M; Chinn, D & Hay, T
Partner: UNT Libraries Government Documents Department

Ultrasonic Calibration Wire Test Phantom

Description: We designed and built a phantom consisting of vertical wires maintained under tension to be used as an ultrasonic test, calibration, and reconstruction object for the Lawrence Livermore National Laboratory annular array scanner. We provide a description of the phantom, present example data sets, preliminary reconstructions, example metadata, and MATLAB codes to read the data.
Date: September 24, 2004
Creator: Lehman, S K; Fisher, K A; Werve, M & Chambers, D H
Partner: UNT Libraries Government Documents Department

Surface and Tower Meteorological Instrumentation at Barrow (METTWR4H) Handbook

Description: The Barrow meteorology station (BMET) uses mainly conventional in situ sensors mounted at four different heights (2m, 10m, 20m and 40m) on a 40 m tower to obtain profiles of wind speed, wind direction, air temperature, dew point and humidity. It also obtains barometric pressure, visibility and precipitation data from sensors at the base of the tower. Additionally, a Chilled Mirror Hygrometer and an Ultrasonic wind speed sensor are located near the 2m level for comparison purposes.
Date: April 1, 2008
Creator: Ritsche, MT
Partner: UNT Libraries Government Documents Department

Mointoring Thickness Deviations in Planar Multi-Layered Elastic Structures Using Impedance Signatures

Description: In this letter, a low frequency ultrasonic resonance technique that operates in the (20 - 80 kHz) regime is presented that demonstrates detection of thickness changes on the order of +/- 10{micro}m. This measurement capability is a result of the direct correlation between the electrical impedance of an electro-acoustic transducer and the mechanical loading it experiences when placed in contact with a layered elastic structure. The relative frequency shifts of the resonances peaks can be estimated through a simple one-dimensional transmission model. Separate experimental measurements confirm this technique to be sensitive to subtle changes in the underlying layered elastic structure.
Date: January 26, 2007
Creator: Fisher, K A
Partner: UNT Libraries Government Documents Department

Testing Results of Magnetostrictive Ultrasonic Sensor Cables for Signal Loss

Description: The purpose of this test was to determine the signal strength and resolution losses of a magnetostrictive ultrasonic system with an extended signal cable. The cable of interest carries electrical signals between the pulse generator/receiver and the magnetostrictive transducer. It was desired to determine the loss introduced by different lengths of the signal cable (6', 100', and 200').
Date: May 1, 2005
Creator: Evans, JT
Partner: UNT Libraries Government Documents Department

Technical Letter Report Assessment of Ultrasonic Phased Array Testing for Cast Austenitic Stainless Steel Pressurizer Surge Line Piping Welds and Thick Section Primary System Cast Piping Welds JCN N6398, Task 2A

Description: Research is being conducted for the NRC at PNNL to assess the effectiveness and reliability of advanced NDE methods for the inspection of LWR components. The scope of this research encompasses primary system pressure boundary materials including cast austenitic stainless steels (CASS), dissimilar metal welds (DMWs), piping with corrosion-resistant cladding, weld overlays, and far-side examinations of austenitic piping welds. A primary objective of this work is to evaluate various NDE methods to assess their ability to detect, localize, and size cracks in coarse-grained steel components. This interim technical letter report (TLR) provides a synopsis of recent investigations at PNNL aimed at evaluating the capabilities of phased-array (PA) ultrasonic testing (UT) methods as applied to the inspection of CASS welds in nuclear reactor piping. A description of progress, recent developments and interim results are provided.
Date: July 21, 2008
Creator: Diaz, Aaron A.; Denslow, Kayte M.; Cinson, Anthony D.; Morra, Marino; Crawford, Susan L.; Prowant, Matthew S. et al.
Partner: UNT Libraries Government Documents Department

Low power acoustic harvesting of aerosols

Description: A new acoustic device for levitation and/or concentration of aerosols and sniall liquid/solid samples (up to several millimeters in diameter) in air has been developed. The device is inexpensive, low-power, and, in its simplest embodiment, does not require accurate alignmen1 of a resonant cavity. It is constructed from a cylindrical PZT tube of outside diameter D = 19.0 mm and thickness-to-radius ratio h/a - 0.03. The lowest-order breathing mode of the tube is tuned to match a resonant mode of the interior air-filled cylindrical cavity. A high Q cavity results that can be driven efficiently. An acoustic standing wave is created in the inteirior cavity of the cylindrical shell where particle concrmtration takes place at the nodal planes of the field. It is shown that drops of water in excess of 1 mm in diameter may be levitated against the force of gravity for approxirnately 100 mW of input electrical power. The main objective of the research is to implement this lowpower device to concentrate and harvest aerosols in a flowing system. Several different cavity geonietries iwe presented for efficient collection of 1 he conaartratetl aerosols. Concentraiion factors greater than 40 iue demonstrated for particles of size 0.7 1.1 in a flow volume of 50 L/minute.
Date: January 1, 2001
Creator: Kaduchak, G. (Gregory) & Sinha, D. N. (Dipen N)
Partner: UNT Libraries Government Documents Department

Robotic Welding and Inspection System

Description: This paper presents a robotic system for GTA welding of lids on cylindrical vessels. The system consists of an articulated robot arm, a rotating positioner, end effectors for welding, grinding, ultrasonic and eddy current inspection. Features include weld viewing cameras, modular software, and text-based procedural files for process and motion trajectories.
Date: June 1, 2008
Creator: Smartt, H. B.; Pace, D. P.; Larsen, E. D.; McJunkin, T. R.; Nichol, C. I.; Clark, D. E. et al.
Partner: UNT Libraries Government Documents Department

Ultrasonic Frequency Difference Generation to Characterize Fluids in Saturated Berea Sandstone.

Description: The use of nonlinear acoustics to characterize fluids in porous media is presented. The acoustic nonlinearity in sandstone is affected by the presence of water or oil. This difference in properties that affect the sound propagation through such media can be used to determine whether a piece of sandstone contains water or oil. Traditional methods of characterizing porous media usually rely on the transmission or reflection of a single ultrasonic probe pulse. The technique presented in this paper uses a method of generating a probe pulse inside the porous medium from the interaction of two pulses. Information about the medium is then contained in the propagation of this probe signal back to a receiver. The main advantage of this approach is that it allows implementation of this technique inside a borehole for characterizing the porous media outside.
Date: January 1, 2001
Creator: Keatkowski, C. S. (MST-11) & Sinha, D. N. (Dipen N)
Partner: UNT Libraries Government Documents Department

Evaluation of Cavitation-Erosion Resistance of 316LN Stainless Steel in Mercury Containing Metallic Solutes

Description: Room temperature cavitation tests of vacuum annealed type 316LN stainless steel were performed in pure Hg and in Hg with various amounts of metallic solute to evaluate potential mitigation of erosion/wastage. Tests were performed using an ultrasonic vibratory horn with specimens attached at the tip. All of the solutes examined, which included 5 wt% In, 10 wt% In, 4.4 wt% Cd, 2 wt% Ga, and a mixture that included 1 wt% each of Pb, Sn, and Zn, were found to increase cavitation-erosion as measured by increased weight loss and/or surface profile development compared to exposures for the same conditions in pure Hg. Qualitatively, each solute appeared to increase the post-test wetting tenacity of the Hg solutions and render the Hg mixture susceptible to manipulation of droplet shape.
Date: August 1, 2006
Creator: Pawel, Steven J & Mansur, Louis K
Partner: UNT Libraries Government Documents Department

NONINVASIVE, NONCONTACT FLUID DETECTION IN SUBMERGED CONTAINERS USING SWEPT FREQUENCY ULTRASONIC TECHNIQUE.

Description: A noncontact technique has been developed for the remote interrogation of submerged and limited access metal containers for determining the presence of fluid inside, The technique is based on the damping effect of water on the thickness mode resonance of the container wall. A transmitter-receiver pair of piezoelectric transducers is placed at a standoff distance of 5 mm from the container wall with the water outside the container providing ultrasonic coupling medium. The excitation frequency applied to the transmitter is swept between 0.8-4.0M Hz and the receiver transducer detects the signal, in the form of a frequency spectrum, returned from the wall. By analyzing the variation in the observed spectrum, it is straightforward to determine whether the container is fluid or air backed thereby detecting if the container has leaked.
Date: January 1, 2001
Creator: Laboratory, Los Alamos National
Partner: UNT Libraries Government Documents Department

Degassing of Aluminum Alloys Using Ultrasonic Vibration

Description: The research was intended to lead to a better fundamental understanding of the effect of ultrasonic energy on the degassing of liquid metals and to develop practical approaches for the ultrasonic degassing of alloys. The goals of the project described here were to evaluate core principles, establish a quantitative basis for the ultrasonic degassing of aluminum alloy melts, and demonstrate the application of ultrsaonic processing during ingot casting and foundry shape casting.
Date: June 1, 2006
Creator: Meek, T. T.; Han, Q. & Xu, H.
Partner: UNT Libraries Government Documents Department