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Electromagnetic-Acoustic-Transducer/Synthetic-Aperture System for Thick-Weld Inspection

Description: Abstract: This report describes a system based on electromagnetic-acoustic transducers (EMATs) as an approach to automated nondestructive evaluation of thick weldments (>25 mm). Good signal-to-noise ratios, often a problem with EMATs, were possibTe through careful design of the transducers and associated electronic circuits and the use of signal averaging. At 454 kHz, the transducers produce shear-horizontal waves of approximately 7-mm wavelength in steel. The long wavelength permits determination of through-thickness flaw depth from the amplitudes of scattered ultrasonic waves. A minicomputer controlled transducer positioning and acquired the digitized ultrasonic waveforms for synthetic aperture processing. The synthetic aperture technique further improved signal quality and yielded flaw localization through the weld thickness. Measurements on artificial flaws demonstrated a detectability threshold of 0.5 mm (through thickness) and sizing ability up to 2.5 mm, in agreement with theoretical predictions. Details include the design of the transducers and electronics, as well as the mechanical positioner, signal processing algorithms, and complete computer program listing.
Date: 1984
Creator: Fortunko, C. M.; Schramm, R. E.; Moulder, J. C. & McColskey, J. D.
Partner: UNT Libraries Government Documents Department

An Anticipatory Model of Cavitation

Description: The Anticipatory System (AS) formalism developed by Robert Rosen provides some insight into the problem of embedding intelligent behavior in machines. AS emulates the anticipatory behavior of biological systems. AS bases its behavior on its expectations about the near future and those expectations are modified as the system gains experience. The expectation is based on an internal model that is drawn from an appeal to physical reality. To be adaptive, the model must be able to update itself. To be practical, the model must run faster than real-time. The need for a physical model and the requirement that the model execute at extreme speeds, has held back the application of AS to practical problems. Two recent advances make it possible to consider the use of AS for practical intelligent sensors. First, advances in transducer technology make it possible to obtain previously unavailable data from which a model can be derived. For example, acoustic emissions (AE) can be fed into a Bayesian system identifier that enables the separation of a weak characterizing signal, such as the signature of pump cavitation precursors, from a strong masking signal, such as a pump vibration feature. The second advance is the development of extremely fast, but inexpensive, digital signal processing hardware on which it is possible to run an adaptive Bayesian-derived model faster than real-time. This paper reports the investigation of an AS using a model of cavitation based on hydrodynamic principles and Bayesian analysis of data from high-performance AE sensors.
Date: April 5, 1999
Creator: Allgood, G.O.; Dress, W.B., Jr.; Hylton, J.O. & Kercel, S.W.
Partner: UNT Libraries Government Documents Department

Response of a recessed pressure transducer with a millisecond pressure step input

Description: All too often, dynamic pressure measurements are made with the sensitive part of the transducer, the diaphragm, recessed and away from the pressure source. If the transducer has been recessed far enough from the pressure source, an invalid pressure measurement will result. To explore the effect of recessing, the Reynolds pneumatic accelerator was used to produce a pressure step with a rise time from 0.5 to 2 ms. Results are presented. (auth)
Date: November 30, 1973
Creator: Shay, W. M. & Kuhlman, J.
Partner: UNT Libraries Government Documents Department

LLNL heart valve condition classification project anechoic testing results at the TRANSDEC evaluation facility

Description: This report first briefly outlines the procedures and support/activation fixture developed at LLNL to perform the heart valve tests in an anechoic-like tank at the US Navy Transducer Evaluation Facility (TransDec) located in San Diego, CA. Next they discuss the basic experiments performed and the corresponding experimental plan employed to gather meaningful data systematically. The signal processing required to extract the desired information is briefly developed along with some of the data. Finally, they show the results of the individual runs for each valve, point out any of the meaningful features and summaries.
Date: October 31, 1999
Creator: Candy, J V
Partner: UNT Libraries Government Documents Department

Horizontal Advanced Tensiometer

Description: An horizontal advanced tensiometer is described that allows the monitoring of the water pressure of soil positions, particularly beneath objects or materials that inhibit the use of previous monitoring wells. The tensiometer includes a porous cup, a pressure transducer (with an attached gasket device), an adaptive chamber, at least one outer guide tube which allows access to the desired horizontal position, a transducer wire, a data logger and preferably an inner guide tube and a specialized joint which provides pressure on the inner guide tube to maintain the seal between the gasket of the transducer and the adaptive chamber.
Date: June 22, 2004
Creator: Hubbell, Joel M. & Sisson, James B.
Partner: UNT Libraries Government Documents Department

Groundwater Level Status Report for 2005 Los Alamos National Laboratory

Description: The status of groundwater level monitoring at Los Alamos National Laboratory (LANL) in 2005 is provided in this report. The Groundwater Level Monitoring Project was instituted in 2005 to provide a framework for the collection and processing of quality controlled groundwater level data. This report summarizes groundwater level data for 137 monitoring wells, including 41 regional aquifer wells, 22 intermediate wells, and 74 alluvial wells. Pressure transducers were installed in 118 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well.
Date: May 15, 2006
Creator: Allen, S.P. & Koch, R.J.
Partner: UNT Libraries Government Documents Department

Intricate Mechanisms-on-a Chip Enabled by 5-Level Surface Micromachining

Description: Surface micromachining generally offers more design freedom than related technologies, and it is the technology of choice for most microelectromechanical applications that require multi-level structures. However, the design flexibility that surface micromachining offers is not without limitations. In addition to determining how to fabricate devices in a planar world, the designer also needs to consider issues such as film quality, thickness, residual stress, topography propagation, stringers, processing limitations, and concerns about surface adhesion [1]. Only a few years ago, these were the types of issues that limited design complexity. As the technology improved, the number of mechanical layers available to the designer became the dominant constraint on system functionality. In response, we developed a 5-level polysilicon fabrication technology [2] that offers an unprecedented level of microelectromechanical complexity with simultaneous increases in system yield and robustness. This paper outlines the application that was the driving force behind this work and describes the first devices specifically designed for and fabricated in this technology. The 5-level fabrication technology developed to support this program is known as SUMMiT-V. Four mechanical layers of polysilicon referred to as polyl, poly2, poly3, and poly4 are fabricated above a polyO electrical interconnect and ground plane layer [2,4]. PolyO is 0.3 pm thick, polyl is 1.0 pm, poly 2 is 1.5 pm, and both poly3 and poly4 are 2.25 pm. All films except polyl and poly2 are separated by 2-pm thick depositions of sacrificial oxide. A 0.5-m sacrificial oxide between polyl and poly2 typically defines the clearance between close mating parts such as hubs and hinges. This entire stack is built on a single crystal substrate with a dielectric foundation of 0.8 pm of nitride over 0.63 m of oxide. Seventeen drawing layer are combined to generate the 14 photolithographic masks used to pattern these films during a 240-step ...
Date: March 30, 1999
Creator: Allen, J.J.; McWhorter, P.J.; Miller, S.L.; Rodgers, M.S.; Smith, J.H. & Sniegowski, J.J.
Partner: UNT Libraries Government Documents Department

Groundwater level status report for 2009, Los Alamos National Laboratory

Description: The status of groundwater level monitoring at Los Alamos National Laboratory in 2009 is provided in this report. This report summarizes groundwater level data for 179 monitoring wells, including 55 regional aquifer wells (including 11 regional/intermediate wells), 26 intermediate wells, 98 alluvial wells, and 12 water supply wells. Pressure transducers were installed in 161 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well. The report also summarizes the groundwater temperatures recorded in intermediate and regional aquifer monitoring wells.
Date: March 1, 2010
Creator: Koch, Richard J. & Schmeer, Sarah
Partner: UNT Libraries Government Documents Department

Groundwater Level Status Report for Fiscal Year 2006 Los Alamos National Laboratory

Description: The status of groundwater level monitoring at Los Alamos National Laboratory in Fiscal Year 2006 is provided in this report. The Groundwater Level Monitoring Project was instituted in 2005 for providing a framework for the collection and processing of quality controlled groundwater level data. This report summarizes groundwater level data for 158 monitoring wells, including 43 regional aquifer wells, 23 intermediate wells, and 92 alluvial wells. Pressure transducers were installed in 132 monitoring wells for continuous monitoring of groundwater levels. Time-series hydrographs of groundwater level data are presented along with pertinent construction and location information for each well.
Date: March 30, 2007
Creator: Allen, Shannon P. & Koch, Richard J.
Partner: UNT Libraries Government Documents Department

High Frequency Laser-Based Ultrasound

Description: To obtain micrometer resolution of materials using acoustics requires frequencies around 1 GHz. Attenuation of such frequencies is high, limiting the thickness of the parts that can be characterized. Although acoustic microscopes can operate up to several GHz in frequency, they are used primarily as a surface characterization tool. The use of a pulsed laser for acoustic generation allows generation directly in the part, eliminating the loss of energy associated with coupling the energy from a piezoelectric transducer to the part of interest. The use of pulsed laser acoustic generation in combination with optical detection is investigated for the non-contact characterization of materials with features that must be characterized to micrometer resolution.
Date: September 12, 2005
Creator: Huber, R; Chinn, D; Balogun, O & Murray, T
Partner: UNT Libraries Government Documents Department

User’s Guide for Getter Rate Test System

Description: This User’s Guide describes the operation and maintenance of the Getter Rate Test System, including the mechanical equipment, instrumentation, and datalogger/computer components. The Getter Rate Test System includes equipment and instrumentation to conduct two getter rate tests simultaneously. The mechanical equipment comprises roughing and high-vacuum pumps, heated test chambers, standard hydrogen leaks, and associated piping and valves. Instrumentation includes thermocouples, pressure (vacuum) transducers, panel displays, analog-to-digital signal converter, and associated wiring. The datalogger/computer is a stand-alone computer with installed software to allow the user to record data input from the pressure transducers to data files and to calculate the getter rate from the data in an Excel® spreadsheet.
Date: June 27, 2007
Creator: Elmore, Monte R.
Partner: UNT Libraries Government Documents Department

Mesoscale wide-bandwidth linear magnetic actuators : an LDRD final report.

Description: As MEMS transducers are scaled up in size, the threshold is quickly crossed to where magnetoquasistatic (MQS) transducers are superior for force production compared to electroquasistatic (EQS) transducers. Considerable progress has been made increasing the force output of MEMS EQS transducers, but progress with MEMS MQS transducers has been more modest. A key reason for this has been the difficulty implementing efficient lithographically-fabricated magnetic coil structures. The contribution of this study is a planar multilayer polyphase coil architecture which provides for the lithographic implementation of efficient stator windings suitable for linear magnetic machines. A millimeter-scale linear actuator with complex stator windings was fabricated using this architecture. The stators of the actuator were fabricated using a BCB/Cu process, which does not require replanarization of the wafer between layers. The prototype stator was limited to thin copper layers (3 {micro}m) due to the use of evaporated metal at the time of fabrication. Two layers of metal were implemented in the prototype, but the winding architecture naturally supports additional metal layer pairs. It was found in laboratory tests that the windings can support very high current densities of 4 x 10{sup 9}A/m{sup 2} without damage. Force production normal to the stator was calculated to be 0.54 N/A. For thin stators such as this one, force production increases approximately linearly with the thickness of the windings and a six-layer stator fabricated using a newly implemented electroplated BCB/Cu process (six layers of 15 {micro}m thick metal) is projected to produce approximately 8.8 N/A.
Date: February 1, 2004
Creator: Jones, Lawrence Anthony
Partner: UNT Libraries Government Documents Department

KAWICH-A: Containment data report

Description: This report briefly describes the KAWICH-A event, containment, and measuring instruments utilized. Diagrams are presented on pressure and radiation histories, containment instrumentation plan, and sanded gypsum emplacement.
Date: August 1, 1994
Creator: Heinle, R. & Stubbs, T.
Partner: UNT Libraries Government Documents Department

WATERSHED MANAGEMENT ON THE PAJARITO PLATEAU: PAST, PRESENT, AND FUTURE

Description: Los Alamos National Laboratory (LANL) developed a draft watershed-management plan that pertains to the 43-mi{sup 2} area within the LANL boundaries. The watershed-management plan was started in 1996 with a number of overall goals: (1) to be a good steward of the natural resources entrusted to the laboratory, (2) to provide long-term evaluation regarding success of the Environmental Restoration Project in acceptably cleaning up sites, (3) compliance with the storm water National Pollution Discharge Elimination System program, and (4) upgrading the LANL environmental surveillance program that has been ongoing since the 1940s. LANL has an extensive network consisting of 53 surface-water-monitoring stations located in every major canyon, upstream and downstream of LANL, and at most confluences. Monitoring of the network has been ongoing for about 20 years. The stations are equipped with ultrasonic transducers that trip automated samplers to collect water samples from every flow event. These data have been reported every year in the report series Environmental Surveillance at Los Alamos, but have not been used to analyze watershed health. The focus of the LANL watershed-management plan is to use water quality data to monitor watershed health and to implement management actions when LANL activities, past or present, adversely impact the health of the watershed.
Date: January 1, 2001
Creator: MULLEN, K. & BITNER, K.
Partner: UNT Libraries Government Documents Department

Real-Time Measurement of Rates of Outdoor Airflow into HVACSystems: A Field Study of Three Technologies

Description: Technologies for real-time continuous measurement of the flow rates of outdoor air (OA) into HVAC systems are now available commercially. Our prior papers reported on laboratory-based evaluations of these measurement technologies and this document describes the methods and results of a field study of the accuracy of three of these technologies. From the field study data, we determined that neither wind speed nor wind direction have an important adverse impact on measurement accuracy. The field study confirmed that these three measurement technologies can provide reasonably accurate measurements of outdoor air intake rates in field settings, if the pressure signals are measured with high accuracy. Some of the pressure transducers marketed for use with commercial HVAC systems were determined to be sufficiently accurate for this application. Given the significant impact of OA flow rates on both energy use and occupant health, more widespread use of technologies that provide for real time measurements of OA flow rates seems warranted.
Date: September 1, 2005
Creator: Fisk, William J.; Sullivan, Douglas P. & Faulkner, David
Partner: UNT Libraries Government Documents Department

Uncooled Micro-Cantilever Infrared Imager Optimization

Description: We report on the development, fabrication and characterization of microcantilever based uncooled focal plane array (FPA) for infrared imaging. By combining a streamlined design of microcantilever thermal transducers with a highly efficient optical readout, we minimized the fabrication complexity while achieving a competitive level of imaging performance. The microcantilever FPAs were fabricated using a straightforward fabrication process that involved only three photolithographic steps (i.e. three masks). A designed and constructed prototype of an IR imager employed a simple optical readout based on a noncoherent low-power light source. The main figures of merit of the IR imager were found to be comparable to those of uncooled MEMS infrared detectors with substantially higher degree of fabrication complexity. In particular, the NETD and the response time of the implemented MEMS IR detector were measured to be as low as 0.5K and 6 ms, respectively. The potential of the implemented designs can also be concluded from the fact that the constructed prototype enabled IR imaging of close to room temperature objects without the use of any advanced data processing. The most unique and practically valuable feature of the implemented FPAs, however, is their scalability to high resolution formats, such as 2000 x 2000, without progressively growing device complexity and cost. The overall technical objective of the proposed work was to develop uncooled infrared arrays based on micromechanical sensors. Currently used miniature sensors use a number of different readout techniques to accomplish the sensing. The use of optical readout techniques sensing require the deposition of thin coatings on the surface of micromechanical thermal detectors. Oak Ridge National Laboratory (ORNL) is uniquely qualified to perform the required research and development (R&D) services that will assist our ongoing activities. Over the past decade ORNL has developed a number of unique methods and techniques that led to improved ...
Date: February 5, 2008
Partner: UNT Libraries Government Documents Department

Chemical class specificity using self-assembled monolayers on SAW devices

Description: We have studied the chemical selectivity and sensitivity of surface acoustic wave (SAW) sensors covered by (COO{sup {minus}}){sub 2}/Cu{sup 2+}-terminated interfaces by examining the response of self-assembled monolayer (SAM) films formed from the solution phase for 36, 84, and 180 h adsorption times. These organomercaptan SAMs were prepared on thin-film Au surfaces having variable, controlled grain size. The SAW response from the carboxylate coordinated Cu{sup 2+}-terminated SAM is compared to that from methyl-terminated SAM, as these films interact with a vapor-phase organophosphonate analyte and the vapors of common organic solvents. Results have implications for designing and reliably fabricating chemical sensors that respond to specific organic analytes.
Date: June 1, 1996
Creator: Thomas, R.C.; Ricco, A.J.; Yang, H.C.; Dermody, D. & Crooks, R.M.
Partner: UNT Libraries Government Documents Department

A TRAPEZOIDAL-WAVE ELECTROMAGNETIC BLOOD FLOWMETER

Description: The electromagnetic flowmeter is an instrument that measures the velocity of a fluid moving in a tube or pipe. By constraining the vessel in a sleeve, flow may be measured directly. A magnetic field crosses the tube at 90 deg to the axis of the tube and to the plane of the electrcdes. As the ions in the fiuid pass the magnetic field, a voltage is induced in the electrode. This fiowmeter is different from existing fiowmeters because of the unique trapezoidal waveform that energizes the magnet. It was found that there are serious difficulties with electromagnetic flowmeters using sine waves or square waves. The trapezoidal-wave electromagnetic blocd flowmeter is described. This new flowmeter is compared with other types of electromagnetic flowmeters. The construction of the transducer element is also discussed. (auth)
Date: June 1, 1960
Creator: Yanof, H M & Salz, P
Partner: UNT Libraries Government Documents Department

A new mechanical characterization method for microactuators applied to shape memory films

Description: We present a new technique for the mechanical characterization of microactuators and apply it to shape memory alloy (SMA) thin films. A test instrument was designed which utilizes a spring-loaded transducer to measure displacements with resolution of 1.5 mm and forces with resolution of 0.2 mN. Employing an out- of-plane loading method for SMA thin films, strain resolution of 30 me and stress resolution of 2.5 MPa were achieved. Four mm long, 2 {micro}m thick NiTiCu ligaments suspended across open windows were bulk micromachined for use in the out-of-plane stress and strain measurements. Static analysis showed that 63% of the applied strain was recovered while ligaments were subjected to tensile stresses of 870 MPa. This corresponds to 280 mm of actual displacement against a load of 52 mN. Fatigue analysis of the ligaments showed 33% degradation in recoverable strain (from 0.3% to 0.2%) with 2 {+-} 10{sup 4} cycles for an initial strain of 2.8%.
Date: March 1, 1999
Creator: Ackler, H D; Krulevitch, P; Ramsey, P B & Seward, K P
Partner: UNT Libraries Government Documents Department

Techniques for enhancing laser ultrasonic nondestructive evaluation

Description: Ultrasonic nondestructive evaluation is an extremely powerful tool for characterizing materials and detecting defects. A majority of the ultrasonic nondestructive evaluation is performed with piezoelectric transducers that generate and detect high frequency acoustic energy. The liquid needed to couple the high frequency acoustic energy from the piezoelectric transducers restricts the applicability of ultrasonics. For example, traditional ultrasonics cannot evaluate parts at elevated temperatures or components that would be damaged by contact with a fluid. They are developing a technology that remotely generates and detects the ultrasonic pulses with lasers and consequently there is no requirement for liquids. Thus the research in laser-based ultrasound allows them to solve inspection problems with ultrasonics that could not be done before. This technology has wide application in many Lawrence Livermore National Laboratory programs, especially when remote and/or non-contact sensing is necessary.
Date: February 16, 1999
Creator: Candy, J; Chinn, D; Huber, R; Spicer, J & Thomas, G
Partner: UNT Libraries Government Documents Department