Science.gov

Sample records for acoustic fatigue apparatus

  1. Capabilities of the thermal acoustic fatigue apparatus

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.; Daniels, E. F.

    1992-01-01

    The Thermal Acoustic Fatigue Apparatus (TAFA) is a facility for applying intense noise and heat to small test panels. Modifications to TAFA have increased the heating capability to 44 BTU/(ft.-sec.), making it possible to heat test panels to 2000 F and concurrently apply 168 dB of noise. Results of acoustic and thermal surveys are shown. Two test items, a 0.09 in. steel panel and an insulated panel, were used in the thermal survey.

  2. Enhanced Capabilities of the NASA Langley Thermal Acoustic Fatigue Apparatus

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A.; Turner, Travis L.

    2004-01-01

    This paper presents newly enhanced acoustic capabilities of the Thermal Acoustic Fatigue Apparatus at the NASA Langley Research Center. The facility is a progressive wave tube used for sonic fatigue testing of aerospace structures. Acoustic measurements for each of the six facility configurations are shown and comparisons with projected performance are made.

  3. Improved acoustic levitation apparatus

    NASA Technical Reports Server (NTRS)

    Berge, L. H.; Johnson, J. L.; Oran, W. A.; Reiss, D. A.

    1980-01-01

    Concave driver and reflector enhance and shape levitation forces in acoustic resonance system. Single-mode standing-wave pattern is focused by ring element situated between driver and reflector. Concave surfaces increase levitating forces up to factor of 6 as opposed to conventional flat surfaces, making it possible to suspend heavier objects.

  4. The Acoustical Apparatus of Rudolph Koenig.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1992-01-01

    Discusses the history of Rudolph Koenig's contribution to the development of acoustical apparatus. Contributions include the clock fork to determine absolute acoustic frequencies, a forerunner of the oscilloscope called the manometric flame, and an acoustic interference apparatus used in the Fourier synthesis of musical sounds. (MDH)

  5. Acoustically induced structural fatigue of piping systems

    SciTech Connect

    Eisinger, F.L.; Francis, J.T.

    1999-11-01

    Piping systems handling high-pressure and high-velocity steam and various process and hydrocarbon gases through a pressure-reducing device can produce severe acoustic vibration and metal fatigue in the system. It has been previously shown that the acoustic fatigue of the piping system is governed by the relationship between fluid pressure drop and downstream Mach number, and the dimensionless pipe diameter/wall thickness geometry parameter. In this paper, the devised relationship is extended to cover acoustic fatigue considerations of medium and smaller-diameter piping systems.

  6. Method and apparatus for generating acoustic energy

    DOEpatents

    Guerrero, Hector N.

    2002-01-01

    A method and apparatus for generating and emitting amplified coherent acoustic energy. A cylindrical transducer is mounted within a housing, the transducer having an acoustically open end and an acoustically closed end. The interior of the transducer is filled with an active medium which may include scattering nuclei. Excitation of the transducer produces radially directed acoustic energy in the active medium, which is converted by the dimensions of the transducer, the acoustically closed end thereof, and the scattering nuclei, to amplified coherent acoustic energy directed longitudinally within the transducer. The energy is emitted through the acoustically open end of the transducer. The emitted energy can be used for, among other things, effecting a chemical reaction or removing scale from the interior walls of containment vessels.

  7. Acoustically enhanced heat exchange and drying apparatus

    DOEpatents

    Bramlette, T. Tazwell; Keller, Jay O.

    1989-01-01

    A heat transfer apparatus includes a first chamber having a first heat transfer gas inlet, a second heat transfer gas inlet, and an outlet. A first heat transfer gas source provides a first gas flow to the first chamber through the first heat transfer gas inlet. A second gas flow through a second chamber connected to the side of the first chamber, generates acoustic waves which bring about acoustical coupling of the first and second gases in the acoustically augmented first chamber. The first chamber may also include a material inlet for receiving material to be dried, in which case the gas outlet serves as a dried material and gas outlet.

  8. Pulse combusted acoustic agglomeration apparatus and process

    DOEpatents

    Mansour, Momtaz N.; Chandran, Ravi

    1994-01-01

    An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance agglomeration of particulates which may be collected and removed using a conventional separation apparatus. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, added particulates may include a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.

  9. Pulse combusted acoustic agglomeration apparatus and process

    DOEpatents

    Mansour, Momtaz N.

    1993-01-01

    An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance bimodal agglomeration of particulates which may be collected and removed using a conventional separation apparatus. A particulate having a size different from the size of the particulate in the gas stream to be cleaned is introduced into the system to effectuate the bimodal process. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, the added particulate may be a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.

  10. Acoustically enhanced heat exchange and drying apparatus

    DOEpatents

    Bramlette, T.T.; Keller, J.O.

    1987-07-10

    A heat transfer drying apparatus includes an acoustically augmented heat transfer chamber for receiving material to be dried. The chamber includes a first heat transfer gas inlet, a second heat transfer gas inlet, a material inlet, and a gas outlet which also serves as a dried material and gas outlet. A non-pulsing first heat transfer gas source provides a first drying gas to the acoustically augmented heat transfer chamber through the first heat transfer gas inlet. A valveless, continuous second heat transfer gas source provides a second drying gas to the acoustically augmented heat transfer chamber through the second heat transfer gas inlet. The second drying gas also generates acoustic waves which bring about acoustical coupling with the gases in the acoustically augmented heat transfer chamber. The second drying gas itself oscillates at an acoustic frequency of approximately 180 Hz due to fluid mechanical motion in the gas. The oscillations of the second heat transfer gas coupled to the first heat transfer gas in the acoustically augmented heat transfer chamber enhance heat and mass transfer by convection within the chamber. 3 figs.

  11. Consecutive plate acoustic suppressor apparatus and methods

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph (Inventor); Parrott, Tony (Inventor)

    1992-01-01

    An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.

  12. Consecutive Plate Acoustic Suppressor Apparatus and Methods

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph (Inventor); Parrott, Tony L. (Inventor)

    1993-01-01

    An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.

  13. [Acoustic Levitation Methods and Apparatus

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Jacobi, N. (Inventor)

    1982-01-01

    Methods are described for acoustically levitating objects within chambers of spherical and cylindrical shape. The wavelengths for chambers of particular dimensions are given, for generating standing wave patterns of any of a variety of modes within the chambers. For a spherical chamber the lowest resonant mode is excited by applying a wavelength of 3.02R, where R is the chamber radius. The two lowest pure radial modes for that chamber, are excited by applying wavelengths of 1.40R and 0.814R. For a cylindrical chamber of radius R, the lowest mode is at a wavelength of 3.41R, and the lowest pure radial modes are at wavelengths of 1.64R and 0.896R.

  14. Acoustic levitation methods and apparatus

    NASA Astrophysics Data System (ADS)

    Barmatz, M. B.; Jacobi, N.

    1982-03-01

    Methods are described for acoustically levitating objects within chambers of spherical and cylindrical shape. The wavelengths for chambers of particular dimensions are given, for generating standing wave patterns of any of a variety of modes within the chambers. For a spherical chamber the lowest resonant mode is excited by applying a wavelength of 3.02R, where R is the chamber radius. The two lowest pure radial modes for that chamber, are excited by applying wavelengths of 1.40R and 0.814R. For a cylindrical chamber of radius R, the lowest mode is at a wavelength of 3.41R, and the lowest pure radial modes are at wavelengths of 1.64R and 0.896R.

  15. Dynamic response and acoustic fatigue of stiffened composite structure

    NASA Technical Reports Server (NTRS)

    Soovere, J.

    1984-01-01

    The results of acoustic fatigue and dynamic response tests performed on L-1011 graphite-epoxy (GrE) aileron and panel components are reported. The aileron featured glass microballoons between the GrE skins. Tests yielded random fatigue data from double and single cantilever coupons and modal data from impedance hammer and loudspeaker impulses. Numerical and sample test data were obtained on combined acoustic and shear loads, acoustic and thermal loads, random fatigue and damping of the integrally stiffened and secondary bonded panels. The fatigue data indicate a fatigue life beyond 10 million cycles. The acoustic data suggested that noise transmission could be enhanced in the integrally stiffened panels, which were more acoustic-fatigue resistant than were the secondary bonded panels.

  16. Methods And Apparatus For Acoustic Fiber Fractionation

    DOEpatents

    Brodeur, Pierre

    1999-11-09

    Methods and apparatus for acoustic fiber fractionation using a plane ultrasonic wave field interacting with water suspended fibers circulating in a channel flow using acoustic radiation forces to separate fibers into two or more fractions based on fiber radius, with applications of the separation concept in the pulp and paper industry. The continuous process relies on the use of a wall-mounted, rectangular cross-section piezoelectric ceramic transducer to selectively deflect flowing fibers as they penetrate the ultrasonic field. The described embodiment uses a transducer frequency of approximately 150 kHz. Depending upon the amount of dissolved gas in water, separation is obtained using a standing or a traveling wave field.

  17. Rotor acoustic monitoring system (RAMS): a fatigue crack detection system

    NASA Astrophysics Data System (ADS)

    Schoess, Jeffrey N.

    1996-05-01

    The Rotor Acoustic Monitoring System (RAMS) is an embedded structural health monitoring system to demonstrate the ability to detect rotor head fatigue cracks and provide early warning of propagating fatigue cracks in rotor components of Navy helicopters. The concept definition effort was performed to assess the feasibility of detecting rotor head fatigue cracks using bulk- wave wide-bandwidth acoustic emission technology. A wireless piezo-based transducer system is being designed to capture rotor fatigue data in real time and perform acoustic emission (AE) event detection, feature extraction, and classification. A flight test effort will be performed to characterize rotor acoustic background noise and flight environment characteristics. The long- term payoff of the RAMS technology includes structural integrity verification and leak detection for large industrial tanks, and nuclear plant cooling towers could be performed using the RAMS AE technology. A summary of the RAMS concept, bench-level AE fatigue testing, and results are presented.

  18. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    SciTech Connect

    Kaduchak, Gregory; Ward, Michael D

    2014-10-21

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  19. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    SciTech Connect

    Kaduchak, Gregory; Ward, Michael D.

    2011-12-27

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  20. Apparatus for separating particles utilizing engineered acoustic contrast capture particles

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D

    2016-05-17

    An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.

  1. Computational simulation of acoustic fatigue for hot composite structures

    NASA Technical Reports Server (NTRS)

    Singhal, Surendra N.; Murthy, Pappu L. N.; Chamis, Christos C.; Nagpal, Vinod K.; Sutjahjo, Edhi

    1991-01-01

    Predictive methods/computer codes for the computational simulation of acoustic fatigue resistance of hot composite structures subjected to acoustic excitation emanating from an adjacent vibrating component are discussed. Select codes developed over the past two decades at the NASA Lewis Research Center are used. The codes include computation of acoustic noise generated from a vibrating component, degradation in material properties of a composite laminate at use temperature, dynamic response of acoustically excited hot multilayered composite structure, degradation in the first ply strength of the excited structure due to acoustic loading, and acoustic fatigue resistance of the excited structure, including the propulsion environment. Effects of the laminate lay-up and environment on the acoustic fatigue life are evaluated. The results show that, by keeping the angled plies on the outer surface of the laminate, a substantial increase in the acoustic fatigue life is obtained. The effect of environment (temperature and moisture) is to relieve the residual stresses leading to an increase in the acoustic fatigue life of the excited panel.

  2. Acoustic emission measurement of fatigue crack closure

    SciTech Connect

    Lee, C.S.; Rhyim, Y.M. . Center for Advanced Aerospace Materials); Kwon, D. . Dept. of Metallurgical Engineering); Ono, K. . Dept. of Materials Science and Engineering)

    1995-03-01

    In this study the acoustic emission (AE) technique has been applied to measure the crack closure loads precisely and the results have been compared with those measured by the conventional techniques such as the crack opening displacement (COD) method, back face strain gage (BFS) method, and surface strain gage method. In addition, fatigue tests at high stress ratio (R=0.8) have also been conducted to compared the results with those of the above methods at R=0.1 and to verify the accuracy of each method. The material used in the present investigation was an Al-Li 8090 alloy which was supplied as a 44.5mm thick rolled plate in the solution heat treated, 6% stretched and naturally aged condition. The COD and BFS methods show relatively good agreement with each other and measure the through-thickness mean value of crack closure loads. In the plane strain condition, the crack closure levels obtained by the COD and BFS methods were lower than those by the AE and surface train gage methods. The data obtained by the surface strain gage method must be interpreted carefully, because the shape of the compliance curves is affected by the location relative to the crack tip. The intrinsic fatigue life curve (da/dN vs. [Delta]K[sub eff]) obtained by the AE technique fitted well with the curve of high stress ratio (R=0.8) test at high [Delta]K, suggesting that the AE technique is sensitive to local crack-tip behavior on a microscopic scale and can be considered as a reliable measurement method for crack closure phenomena under repetitive loads.

  3. Nondestructive Evaluation of Metal Fatigue Using Nonlinear Acoustics

    NASA Technical Reports Server (NTRS)

    Cantrell, John H., Jr.

    2008-01-01

    Safe-life and damage-tolerant design philosophies of high performance structures have driven the development of various methods to evaluate nondestructively the accumulation of damage in such structures resulting from cyclic loading. Although many techniques have proven useful, none has been able to provide an unambiguous, quantitative assessment of damage accumulation at each stage of fatigue from the virgin state to fracture. A method based on nonlinear acoustics is shown to provide such a means to assess the state of metal fatigue. The salient features of an analytical model are presented of the microelastic-plastic nonlinearities resulting from the interaction of an acoustic wave with fatigue-generated dislocation substructures and cracks that predictably evolve during the metal fatigue process. The interaction is quantified by the material (acoustic) nonlinearity parameter extracted from acoustic harmonic generation measurements. The parameters typically increase monotonically by several hundred percent over the fatigue life of the metal, thus providing a unique measure of the state of fatigue. Application of the model to aluminum alloy 2024-T4, 410Cb stainless steel, and IN100 nickel-base superalloy specimens fatigued using different loading conditions yields good agreement between theory and experiment. Application of the model and measurement technique to the on-site inspection of steam turbine blades is discussed.

  4. Nondestructive Evaluation of Metal Fatigue Using Nonlinear Acoustics

    NASA Astrophysics Data System (ADS)

    Cantrell, John H.

    2009-03-01

    Safe-life and damage-tolerant design philosophies of high performance structures have driven the development of various methods to evaluate nondestructively the accumulation of damage in such structures resulting from cyclic loading. Although many techniques have proven useful, none has been able to provide an unambiguous, quantitative assessment of damage accumulation at each stage of fatigue from the virgin state to fracture. A method based on nonlinear acoustics is shown to provide such a means to assess the state of metal fatigue. The salient features of an analytical model are presented of the microelastic-plastic nonlinearities resulting from the interaction of an acoustic wave with fatigue-generated dislocation substructures and cracks that predictably evolve during the metal fatigue process. The interaction is quantified by the material (acoustic) nonlinearity parameter β extracted from acoustic harmonic generation measurements. The β parameters typically increase monotonically by several hundred percent over the fatigue life of the metal, thus providing a unique measure of the state of fatigue. Application of the model to aluminum alloy 2024-T4 and 410 Cb stainless steel specimens fatigued using different loading conditions yields good agreement between theory and experiment. Application of the model and measurement technique to the on-site inspection of steam turbine blades is discussed.

  5. Method and apparatus for shaping and enhancing acoustical levitation forces

    NASA Technical Reports Server (NTRS)

    Oran, W. A.; Berge, L. H.; Reiss, D. A.; Johnson, J. L. (Inventor)

    1980-01-01

    A method and apparatus for enhancing and shaping acoustical levitation forces in a single-axis acoustic resonance system wherein specially shaped drivers and reflectors are utilized to enhance to levitation force and better contain fluid substance by means of field shaping is described.

  6. Method and apparatus for shaping and enhancing acoustical levitation forces

    NASA Astrophysics Data System (ADS)

    Oran, W. A.; Berge, L. H.; Reiss, D. A.; Johnson, J. L.

    1980-08-01

    A method and apparatus for enhancing and shaping acoustical levitation forces in a single-axis acoustic resonance system wherein specially shaped drivers and reflectors are utilized to enhance to levitation force and better contain fluid substance by means of field shaping is described.

  7. Design for prevention of acoustic fatigue. [of aircraft structures

    NASA Technical Reports Server (NTRS)

    Smith, H. W.

    1983-01-01

    It is pointed out that new noise prediction methods and acoustic life estimation methods have matured to the point where they can be combined into a unified engineering procedure. "Life derivatives" can be extracted from parametric charts to furnish design data for preventing acoustic fatigue. The acoustic fatigue life is shown to be sensitive to the damping ratio through the use of life derivatives. The localized nature of propeller noise can be quantified with an "isodecibel" contour diagram.Even though the peak sound pressure level may be high, the directional derivatives show the noise decay rates with distance. Acoustic fatigue design is discussed from the overall design methodology and is shown to be similar to other structural design problems. While nonlinearities present a formidable design engineering problem, they are manageable by proven semi-empirical techniques. For new design problems, it is imperative to determine whether the data base completely spans the design variables.

  8. Documentation of the space station/aircraft acoustic apparatus

    NASA Technical Reports Server (NTRS)

    Clevenson, Sherman A.

    1987-01-01

    This paper documents the design and construction of the Space Station/Aircraft Acoustic Apparatus (SS/AAA). Its capabilities both as a space station acoustic simulator and as an aircraft acoustic simulator are described. Also indicated are the considerations which ultimately resulted in man-rating the SS/AAA. In addition, the results of noise surveys and reverberation time and absorption coefficient measurements are included.

  9. Acoustic fatigue: Overview of activities at NASA Langley

    NASA Astrophysics Data System (ADS)

    Mixson, John S.; Roussos, Louis A.

    1987-04-01

    A number of aircraft and spacecraft configurations are being considered for future development. These include high-speed turboprop aircraft, advanced vertical take-off and landing fighter aircraft, and aerospace planes for hypersonic intercontinental cruise or flight to orbit and return. Review of the acoustic environment expected for these vehicles indicates levels high enough that acoustic fatigue must be considered. Unfortunately, the sonic fatique design technology used for current aircraft may not be adequate for these future vehicles. This has resulted in renewed emphasis on acoustic fatigue research at the NASA Langley Research Center. The overall objective of the Langley program is to develop methods and information for design of aerospace vehicles that will resist acoustic fatigue. The program includes definition of the acoustic loads acting on structures due to exhaust jets of boundary layers, and subsequent determination of the stresses within the structure due to these acoustic loads. Material fatigue associated with the high frequency structural stress reversal patterns resulting from acoustic loadings is considered to be an area requiring study, but no activity is currently underway.

  10. Acoustic fatigue: Overview of activities at NASA Langley

    NASA Technical Reports Server (NTRS)

    Mixson, John S.; Roussos, Louis A.

    1987-01-01

    A number of aircraft and spacecraft configurations are being considered for future development. These include high-speed turboprop aircraft, advanced vertical take-off and landing fighter aircraft, and aerospace planes for hypersonic intercontinental cruise or flight to orbit and return. Review of the acoustic environment expected for these vehicles indicates levels high enough that acoustic fatigue must be considered. Unfortunately, the sonic fatique design technology used for current aircraft may not be adequate for these future vehicles. This has resulted in renewed emphasis on acoustic fatigue research at the NASA Langley Research Center. The overall objective of the Langley program is to develop methods and information for design of aerospace vehicles that will resist acoustic fatigue. The program includes definition of the acoustic loads acting on structures due to exhaust jets of boundary layers, and subsequent determination of the stresses within the structure due to these acoustic loads. Material fatigue associated with the high frequency structural stress reversal patterns resulting from acoustic loadings is considered to be an area requiring study, but no activity is currently underway.

  11. Designing piping systems against acoustically-induced structural fatigue

    SciTech Connect

    Eisinger, F.L.

    1996-12-01

    Piping systems adapted for handling fluids such as steam and various process and hydrocarbon gases through a pressure-reducing device at high pressure and velocity conditions can produce severe acoustic vibration and metal fatigue in the system. It has been determined that such vibrations and fatigue are minimized by relating the acoustic power level (PWL) to being a function of the ratio of downstream pipe inside diameter D{sub 2} to its thickness t{sub 2}. Additionally, such vibration and fatigue can be further minimized by relating the fluid pressure drop and downstream mach number to a function of the ratio of downstream piping inside diameter to the pipe wall thickness, as expressed by M{sub 2} {Delta}p = f(D{sub 2}/t{sub 2}). Pressure-reducing piping systems designed according to these criteria exhibit minimal vibrations and metal fatigue failures and have long operating life.

  12. Magneto acoustic emission apparatus for testing materials for embrittlement

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G. (Inventor); Min, Namkung (Inventor); Yost, William T. (Inventor); Cantrell, John H. (Inventor)

    1990-01-01

    A method and apparatus for testing steel components for temper embrittlement uses magneto-acoustic emission to nondestructively evaluate the component. Acoustic emission signals occur more frequently at higher levels in embrittled components. A pair of electromagnets are used to create magnetic induction in the test component. Magneto-acoustic emission signals may be generated by applying an ac current to the electromagnets. The acoustic emission signals are analyzed to provide a comparison between a component known to be unembrittled and a test component. Magnetic remanence is determined by applying a dc current to the electromagnets, then turning the magnets off and observing the residual magnetic induction.

  13. Method and apparatus for acoustic levitation

    SciTech Connect

    Danley, T.J.; Merkley, D.R.; Rey, C.A.

    1991-08-06

    This patent describes a method for acoustically levitating an object along a first axis in a sound transmitting medium. It comprises providing a pair of independent opposed, spaced sound sources along the first axis, operating the sound sources at substantially the same frequency such that the sound waves from the respective sources interfere without use of reflective surfaces and creation of standing waves to create at least one well of acoustic energy between the interfering sound waves, and disposing the object into the one well to acoustically levitate the object.

  14. Gravity enhanced acoustic levitation method and apparatus

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Allen, J. L.; Granett, D. (Inventor)

    1985-01-01

    An acoustic levitation system is provided for acoustically levitating an object by applying a single frequency from a transducer into a resonant chamber surrounding the object. The chamber includes a stabilizer location along its height, where the side walls of the chamber are angled so they converge in an upward direction. When an acoustic standing wave pattern is applied between the top and bottom of the chamber, a levitation surface within the stabilizer does not lie on a horizontal plane, but instead is curved with a lowermost portion near the vertical axis of the chamber. As a result, an acoustically levitated object is urged by gravity towards the lowermost location on the levitation surface, so the object is kept away from the side walls of the chamber.

  15. Gravity enhanced acoustic levitation method and apparatus

    NASA Astrophysics Data System (ADS)

    Barmatz, M. B.; Allen, J. L.; Granett, D.

    1985-06-01

    An acoustic levitation system is provided for acoustically levitating an object by applying a single frequency from a transducer into a resonant chamber surrounding the object. The chamber includes a stabilizer location along its height, where the side walls of the chamber are angled so they converge in an upward direction. When an acoustic standing wave pattern is applied between the top and bottom of the chamber, a levitation surface within the stabilizer does not lie on a horizontal plane, but instead is curved with a lowermost portion near the vertical axis of the chamber. As a result, an acoustically levitated object is urged by gravity towards the lowermost location on the levitation surface, so the object is kept away from the side walls of the chamber.

  16. Early 20th century acoustics apparatus in Iowa

    NASA Astrophysics Data System (ADS)

    Hanson, Roger J.

    2001-05-01

    In the first half of the 20th century G. W. Stewart was a physics faculty member at the University of Iowa (UI) with a distinguished record of research and teaching, especially in acoustics. Much of his research focused on the design and use of several types of acoustical filters. Some apparatus which he developed or utilized are still housed in the Department of Physics and Astronomy or are available in detailed diagrams. Demonstration apparatus (apparently homemade) from his era are still available for use. Carl E. Seashore, a renowned psychologist also at UI in the early 20th century, had interdisciplinary interests linking psychology, speech and hearing, music, and acoustics. He was responsible for obtaining an Henrici harmonic analyzer, a mechanical Fourier analyzer manufactured in Switzerland, a special grant from the state legislature during Depression conditions provided the funding. It resides in the Department of Speech Pathology and Audiology at UI. The Grinnell College Physics Historical Museum houses a set of 18 Helmholtz resonators and a Savart bell and resonator. Apparatus at Iowa State University, the University of Northern Iowa, and other Iowa institutions will also be described. Pictures and diagrams as well as some actual apparatus will be exhibited.

  17. Acoustic transducer apparatus with reduced thermal conduction

    NASA Technical Reports Server (NTRS)

    Lierke, Ernst G. (Inventor); Leung, Emily W. (Inventor); Bhat, Balakrishna T. (Inventor)

    1990-01-01

    A horn is described for transmitting sound from a transducer to a heated chamber containing an object which is levitated by acoustic energy while it is heated to a molten state, which minimizes heat transfer to thereby minimize heating of the transducer, minimize temperature variation in the chamber, and minimize loss of heat from the chamber. The forward portion of the horn, which is the portion closest to the chamber, has holes that reduce its cross-sectional area to minimize the conduction of heat along the length of the horn, with the entire front portion of the horn being rigid and having an even front face to efficiently transfer high frequency acoustic energy to fluid in the chamber. In one arrangement, the horn has numerous rows of holes extending perpendicular to the length of horn, with alternate rows extending perpendicular to one another to form a sinuous path for the conduction of heat along the length of the horn.

  18. Method and apparatus of spectro-acoustically enhanced ultrasonic detection for diagnostics

    DOEpatents

    Vo-Dinh, Tuan; Norton, Stephen J.

    2001-01-01

    An apparatus for detecting a discontinuity in a material includes a source of electromagnetic radiation has a wavelength and an intensity sufficient to induce an enhancement in contrast between a manifestation of an acoustic property in the material and of the acoustic property in the discontinuity, as compared to when the material is not irradiated by the electromagnetic radiation. An acoustic emitter directs acoustic waves to the discontinuity in the material. The acoustic waves have a sensitivity to the acoustic property. An acoustic receiver receives the acoustic waves generated by the acoustic emitter after the acoustic waves have interacted with the material and the discontinuity. The acoustic receiver also generates a signal representative of the acoustic waves received by the acoustic receiver. A processor, in communication with the acoustic receiver and responsive to the signal generated by the acoustic receiver, is programmed to generate informational output about the discontinuity based on the signal generated by the acoustic receiver.

  19. Apparatus for acoustically coupling an ultrasonic transducer with a body

    NASA Technical Reports Server (NTRS)

    Marshall, Scot H. (Inventor)

    1993-01-01

    An apparatus for acoustically coupling an ultrasonic transducer with a body along whose surface waves are to be transmitted includes a wedge having a first surface for acoustically contacting a subject surface area of a body to be measured, on which surface waves are to be transmitted, and a second surface for accoustically contacting an ultrasonic transducer. The wedge includes a cylinder in which the second surface is present and which is movably disposed in a recess in a block in which the first surface is present, for orienting the first surface and the second surface relative to each other so that ultrasonic waves emitted by the ultrasonic transducer generate surface waves which travel on the subject surface area of the body when the ultrasonic transducer is in acoustic contact with the second surface and the first surface is in acoustic contact with the subject surface area of the body. In the preferred embodiment, there is a third surface which is orientable relative to the first surface so that ultrasonic waves emitted by an ultrasonic transducer in contact with the third surface generate surface waves which travel on the subject surface area of the body when the first surface is an acoustic contact with the subject surface area of the body.

  20. Response of stiffened panels for applications to acoustic fatigue

    NASA Technical Reports Server (NTRS)

    Vaicaitis, R.; Choi, S. T.

    1987-01-01

    The surface protection systems of aerospace and aircraft structures are often constructed from discretely stiffened panels. This paper presents an analytical study on dynamic stress response of these structures to random surface flow and acoustic loads. To account for aerodynamic heating of high speed flow, thermal effects are included in the structural model. A generalized transfer matrix procedure is developed to obtain the required dynamic response solutions. Numerical results include spectral densities of stress, response root mean square values and fatigue damage for a variety of loading and thermal conditions.

  1. The application of acoustic emission technique to fatigue crack measurement. [in aluminum alloys

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Davis, W. T.; Crews, J. H., Jr.

    1974-01-01

    The applicability of acoustic emission technique to measure fatigue cracks in aluminum alloy specimens was investigated. There are several variables, such as the metallurgical and the physical treatment of the specimen, that can affect the level of acoustic activity of a fatigue specimen. It is therefore recommended that the acoustic emission technique be supplemented by other nondestructive evaluation methods to obtain quantitative data on crack growth.

  2. Apparatus and method for comparing corresponding acoustic resonances in liquids

    DOEpatents

    Sinha, D.N.

    1999-03-23

    Apparatus and method are disclosed for comparing corresponding acoustic resonances in liquids. The present invention permits the measurement of certain characteristics of liquids which affect the speed of sound therein. For example, a direct correlation between the octane rating of gasoline and the speed of sound in a gasoline sample has been experimentally observed. Therefore, changes in the speed of sound therein can be utilized as a sensitive parameter for determining changes in composition of a liquid sample. The present apparatus establishes interference patterns inside of a liquid without requiring the use of very thin, rigorously parallel ceramic discs, but rather uses readily available piezoelectric transducers attached to the outside surface of the usual container for the liquid and located on the same side thereof in the vicinity of one another. That is, various receptacle geometries may be employed, and the driving and receiving transducers may be located on the same side of the receptacle. The cell may also be constructed of any material that is inert to the liquid under investigation. A single-transducer embodiment, where the same transducer provides the excitation to the sample container and receives signals impressed therein, is also described. 5 figs.

  3. Apparatus and method for comparing corresponding acoustic resonances in liquids

    DOEpatents

    Sinha, Dipen N.

    1999-01-01

    Apparatus and method for comparing corresponding acoustic resonances in liquids. The present invention permits the measurement of certain characteristics of liquids which affect the speed of sound therein. For example, a direct correlation between the octane rating of gasoline and the speed of sound in a gasoline sample has been experimentally observed. Therefore, changes in the speed of sound therein can be utilized as a sensitive parameter for determining changes in composition of a liquid sample. The present apparatus establishes interference patterns inside of a liquid without requiring the use of very thin, rigorously parallel ceramic discs, but rather uses readily available piezoelectric transducers attached to the outside surface of the usual container for the liquid and located on the same side thereof in the vicinity of one another. That is, various receptacle geometries may be employed, and the driving and receiving transducers may be located on the same side of the receptacle. The cell may also be constructed of any material that is inert to the liquid under investigation. A single-transducer embodiment, where the same transducer provides the excitation to the sample container and receives signals impressed therein, is also described.

  4. Acoustic Emission Technique for Characterizing Deformation and Fatigue Crack Growth in Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Raj, Baldev; Mukhopadhyay, C. K.; Jayakumar, T.

    2003-03-01

    Acoustic emission (AE) during tensile deformation and fatigue crack growth (FCG) of austenitic stainless steels has been studied. In AISI type 316 stainless steel (SS), AE has been used to detect micro plastic yielding occurring during macroscopic plastic deformation. In AISI type 304 SS, relation of AE with stress intensity factor and plastic zone size has been studied. In AISI type 316 SS, fatigue crack growth has been characterised using acoustic emission.

  5. Apparatus for real-time acoustic imaging of Rayleigh-Benard convection.

    PubMed

    Kuehn, Kerry; Polfer, Jonathan; Furno, Joanna; Finke, Nathan

    2007-11-01

    We have designed and built an apparatus for real-time acoustic imaging of convective flow patterns in optically opaque fluids. This apparatus takes advantage of recent advances in two-dimensional ultrasound transducer array technology; it employs a modified version of a commercially available ultrasound camera, similar to those employed in nondestructive testing of solids. Images of convection patterns are generated by observing the lateral variation of the temperature dependent speed of sound via refraction of acoustic plane waves passing vertically through the fluid layer. The apparatus has been validated by observing convection rolls in both silicone oil and ferrofluid. PMID:18052477

  6. Embedded and conventional ultrasonic sensors for monitoring acoustic emission during thermal fatigue

    NASA Astrophysics Data System (ADS)

    Trujillo, Blaine; Zagrai, Andrei

    2016-04-01

    Acoustic emission is widely used for monitoring pressure vessels, pipes, critical infrastructure, as well as land, sea and air vehicles. It is one of dominant approaches to explore material degradation under fatigue and events leading to material fracture. Addressing a recent interest in structural health monitoring of space vehicles, a need has emerged to evaluate material deterioration due to thermal fatigue during spacecraft atmospheric reentry. Thermal fatigue experiments were conducted, in which aluminum plates were subjected to localized heating and acoustic emission was monitoring by embedded and conventional acoustic emission sensors positioned at various distances from a heat source. At the same time, surface temperature of aluminum plates was monitored using an IR camera. Acoustic emission counts collected by embedded sensors were compared to counts measured with conventional acoustic emission sensors. Both types of sensors show noticeable increase of acoustic emission activity as localized heating source was applied to aluminum plates. Experimental data demonstrate correlation between temperature increase on the surface of the plates and increase in measured acoustic emission activity. It is concluded that under particular conditions, embedded piezoelectric wafer active sensors can be used for acoustic emission monitoring of thermally-induced structural degradation.

  7. Methods and apparatus for multi-parameter acoustic signature inspection

    DOEpatents

    Diaz, Aaron A.; Samuel, Todd J.; Valencia, Juan D.; Gervais, Kevin L.; Tucker, Brian J.; Kirihara, Leslie J.; Skorpik, James R.; Reid, Larry D.; Munley, John T.; Pappas, Richard A.; Wright, Bob W.; Panetta, Paul D.; Thompson, Jason S.

    2007-07-24

    A multiparameter acoustic signature inspection device and method are described for non-invasive inspection of containers. Dual acoustic signatures discriminate between various fluids and materials for identification of the same.

  8. Deep-water riser fatigue monitoring systems based on acoustic telemetry

    NASA Astrophysics Data System (ADS)

    Li, Baojun; Wang, Haiyan; Shen, Xiaohong; Yan, Yongsheng; Yang, Fuzhou; Hua, Fei

    2014-12-01

    Marine risers play a key role in the deep and ultra-deep water oil and gas production. The vortex-induced vibration (VIV) of marine risers constitutes an important problem in deep water oil exploration and production. VIV will result in high rates of structural failure of marine riser due to fatigue damage accumulation and diminishes the riser fatigue life. In-service monitoring or full scale testing is essential to improve our understanding of VIV response and enhance our ability to predict fatigue damage. One marine riser fatigue acoustic telemetry scheme is proposed and an engineering prototype machine has been developed to monitor deep and ultra-deep water risers' fatigue and failure that can diminish the riser fatigue life and lead to economic losses and eco-catastrophe. Many breakthroughs and innovation have been achieved in the process of developing an engineering prototype machine. Sea trials were done on the 6th generation deep-water drilling platform HYSY-981 in the South China Sea. The inclination monitoring results show that the marine riser fatigue acoustic telemetry scheme is feasible and reliable and the engineering prototype machine meets the design criterion and can match the requirements of deep and ultra-deep water riser fatigue monitoring. The rich experience and field data gained in the sea trial which provide much technical support for optimization in the engineering prototype machine in the future.

  9. Method and apparatus for sizing and separating warp yarns using acoustical energy

    DOEpatents

    Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, Apostolos C.; Kupperman, David S.

    1998-01-01

    A slashing process for preparing warp yarns for weaving operations including the steps of sizing and/or desizing the yarns in an acoustic resonance box and separating the yarns with a leasing apparatus comprised of a set of acoustically agitated lease rods. The sizing step includes immersing the yarns in a size solution contained in an acoustic resonance box. Acoustic transducers are positioned against the exterior of the box for generating an acoustic pressure field within the size solution. Ultrasonic waves that result from the acoustic pressure field continuously agitate the size solution to effect greater mixing and more uniform application and penetration of the size onto the yarns. The sized yarns are then separated by passing the warp yarns over and under lease rods. Electroacoustic transducers generate acoustic waves along the longitudinal axis of the lease rods, creating a shearing motion on the surface of the rods for splitting the yarns.

  10. Method and apparatus for sizing and separating warp yarns using acoustical energy

    DOEpatents

    Sheen, S.H.; Chien, H.T.; Raptis, A.C.; Kupperman, D.S.

    1998-05-19

    A slashing process is disclosed for preparing warp yarns for weaving operations including the steps of sizing and/or desizing the yarns in an acoustic resonance box and separating the yarns with a leasing apparatus comprised of a set of acoustically agitated lease rods. The sizing step includes immersing the yarns in a size solution contained in an acoustic resonance box. Acoustic transducers are positioned against the exterior of the box for generating an acoustic pressure field within the size solution. Ultrasonic waves that result from the acoustic pressure field continuously agitate the size solution to effect greater mixing and more uniform application and penetration of the size onto the yarns. The sized yarns are then separated by passing the warp yarns over and under lease rods. Electroacoustic transducers generate acoustic waves along the longitudinal axis of the lease rods, creating a shearing motion on the surface of the rods for splitting the yarns. 2 figs.

  11. Method and apparatus for acoustic imaging of objects in water

    DOEpatents

    Deason, Vance A.; Telschow, Kenneth L.

    2005-01-25

    A method, system and underwater camera for acoustic imaging of objects in water or other liquids includes an acoustic source for generating an acoustic wavefront for reflecting from a target object as a reflected wavefront. The reflected acoustic wavefront deforms a screen on an acoustic side and correspondingly deforms the opposing optical side of the screen. An optical processing system is optically coupled to the optical side of the screen and converts the deformations on the optical side of the screen into an optical intensity image of the target object.

  12. Can acoustic emission detect the initiation of fatigue cracks: Application to high-strength light alloys used in aeronautics

    NASA Technical Reports Server (NTRS)

    Bathias, C.; Brinet, B.; Sertour, G.

    1978-01-01

    Acoustic emission was used for the detection of fatigue cracking in a number of high-strength light alloys used in aeronautical structures. Among the features studied were: the influence of emission frequency, the effect of surface oxidation, and the influence of grains. It was concluded that acoustic emission is an effective nondestructive technique for evaluating the initiation of fatigue cracking in such materials.

  13. Acoustic emission characteristics of copper alloys under low-cycle fatigue conditions

    NASA Technical Reports Server (NTRS)

    Krampfner, Y.; Kawamoto, A.; Ono, K.; Green, A.

    1975-01-01

    The acoustic emission (AE) characteristics of pure copper, zirconium-copper, and several copper alloys were determined to develop nondestructive evaluation schemes of thrust chambers through AE techniques. The AE counts rms voltages, frequency spectrum, and amplitude distribution analysis evaluated AE behavior under fatigue loading conditions. The results were interpreted with the evaluation of wave forms, crack propagation characteristics, as well as scanning electron fractographs of fatigue-tested samples. AE signals at the beginning of a fatigue test were produced by a sample of annealed alloys. A sample of zirconium-containing alloys annealed repeatedly after each fatigue loading cycle showed numerous surface cracks during the subsequent fatigue cycle, emitting strong-burst AE signals. Amplitude distribution analysis exhibits responses that are characteristic of certain types of AE signals.

  14. Hysteresis and acoustic emission as non-destructive measures of the fatigue process in metals

    NASA Astrophysics Data System (ADS)

    Guralnick, S. A.

    1995-03-01

    Metal fatigue is a result of a cumulative damage process due to repeated cyclic loading which causes premature and unpredictable failure. It is a complicated metallurgical process at the microscopic level which is difficult to accurately explain or model. Despite the complexities, fatigue analysis methods have been developed and are being developed to facilitate fatigue damage assessment and the prediction of fatigue life. This research project is concerned with the behavior of metals subjected to cyclic loading carried to failure. The purpose of this investigation is to develop a relationship between hysteresis loss, hysteresis loop drift, strain amplitudes, and the number of cycles to failure and to correlate this phenomenological description of the fatigue process with mesoscopic observables such as acoustic emission and stress-induced magnetization.

  15. Nondestructive acoustic electric field probe apparatus and method

    DOEpatents

    Migliori, Albert

    1982-01-01

    The disclosure relates to a nondestructive acoustic electric field probe and its method of use. A source of acoustic pulses of arbitrary but selected shape is placed in an oil bath along with material to be tested across which a voltage is disposed and means for receiving acoustic pulses after they have passed through the material. The received pulses are compared with voltage changes across the material occurring while acoustic pulses pass through it and analysis is made thereof to determine preselected characteristics of the material.

  16. Nonlinear response - A time domain approach. [with applications to acoustic fatigue, spacecraft and composite materials

    NASA Technical Reports Server (NTRS)

    Vaicaitis, R.

    1986-01-01

    The present paper reviews the basic concepts of nonlinear response of panels to surface flow and acoustic pressures, simulation of random processes, time domain solutions and the Monte Carlo Method. Applications of this procedure to the orbit-on-demand space vehicles, acoustic fatigue and composite materials are discussed. Numerical examples are included for a variety of nonlinear problems to illustrate the applicability of this method.

  17. A Nonlinear Reduced Order Method for Prediction of Acoustic Fatigue

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Rizzi, Stephen A.

    2006-01-01

    The goal of this investigation is to assess the quality of high-cycle-fatigue life estimation via a reduced order method, for structures undergoing geometrically nonlinear random vibrations. Modal reduction is performed with several different suites of basis functions. After numerically solving the reduced order system equations of motion, the physical displacement time history is obtained by an inverse transformation and stresses are recovered. Stress ranges obtained through the rainflow counting procedure are used in a linear damage accumulation method to yield fatigue estimates. Fatigue life estimates obtained using various basis functions in the reduced order method are compared with those obtained from numerical simulation in physical degrees-of-freedom.

  18. Development on the Tensile Fatigue Test Apparatus and Strength Evaluation of Thin Metal Films

    NASA Astrophysics Data System (ADS)

    Fukushi, Miyuki; Miyata, Hiroshi; Murakami, Akira

    Recently, development of medical devices such as catheter and stent are advanced in the low invasion medical field. Considering the functions of human body are affected severely by the medical devices, the high strength reliability of devices must be secured. In these circumstances, the thin metal film, which has high reliability of strength, is useful structural material for further development of low invasion medical device. As the strength characteristics of a thin film depend on thickness and formation process of itself, there is little strength database concerning a thin metal film. In this study, a tensile fatigue testing apparatus with cyclic loading frequency up to 30Hz and maximum loading 8 N for the thin metal film has been developed, and thin rolled films Ti and SUS304 were evaluated on tensile and load-controlled fatigue strength. The static tensile tests give that both are also over the twice of the bulk material on the tensile strength, and the proof stress is high-strength with over 90% of tensile strength respectively. The fatigue test shows that Ti thin film has long life in comparison with the bulk material, however, the fatigue characteristic itself is similar like that of bulk material.

  19. Reduced Order Methods for Prediction of Thermal-Acoustic Fatigue

    NASA Technical Reports Server (NTRS)

    Przekop, A.; Rizzi, S. A.

    2004-01-01

    The goal of this investigation is to assess the quality of high-cycle-fatigue life estimation via a reduced order method, for structures undergoing random nonlinear vibrations in a presence of thermal loading. Modal reduction is performed with several different suites of basis functions. After numerically solving the reduced order system equations of motion, the physical displacement time history is obtained by an inverse transformation and stresses are recovered. Stress ranges obtained through the rainflow counting procedure are used in a linear damage accumulation method to yield fatigue estimates. Fatigue life estimates obtained using various basis functions in the reduced order method are compared with those obtained from numerical simulation in physical degrees-of-freedom.

  20. A tension-torsional fatigue testing apparatus for micro-scale components

    NASA Astrophysics Data System (ADS)

    Fu, Sichao; Wang, Lei; Chen, Gang; Yu, Dunji; Chen, Xu

    2016-01-01

    Mechanical characterization of micro-scale components under complex loading conditions is a great challenge. To meet such a challenge, a microtension-torsional fatigue testing apparatus is developed in this study that specializes in the evaluation of multiaxial fatigue behavior of thin stent wires. The actuation and measurement in two controlled directions are incorporated in the tensile and torsional load frames, respectively, and a thrust air bearing is applied for the coupling of the two frames. The axial deformation of specimens measured by a grating sensor built in the linear motor and by a non-contact displacement detect system is compared and corrected. The accuracy of the torque measurement is proved by torsion tests on thin wires of 316L stainless steel in nominal diameters of 100 μm. Multistep torsion test, multiaxial ratcheting test, and a fully strain controlled multiaxial cyclic test are performed on 100 μm and 200 μm-diameter 316L wires using this apparatus. The capability of the equipment in tension-torsional cyclic tests for micro-scale specimens is demonstrated by the experimental results.

  1. Development of a standing wave apparatus for calibrating acoustic vector sensors and hydrophones.

    PubMed

    Lenhart, Richard D; Sagers, Jason D; Wilson, Preston S

    2016-01-01

    An apparatus was developed to calibrate acoustic hydrophones and vector sensors between 25 and 2000 Hz. A standing wave field is established inside a vertically oriented, water-filled, elastic-walled waveguide by a piston velocity source at the bottom and a pressure-release boundary condition at the air/water interface. A computer-controlled linear positioning system allows a device under test to be precisely located in the water column while the acoustic response is measured. Some of the challenges of calibrating hydrophones and vector sensors in such an apparatus are discussed, including designing the waveguide to mitigate dispersion, understanding the impact of waveguide structural resonances on the acoustic field, and developing algorithms to post-process calibration measurement data performed in a standing wave field. Data from waveguide characterization experiments and calibration measurements are presented and calibration uncertainty is reported. PMID:26827015

  2. Method and apparatus for acoustic plate mode liquid-solid phase transition detection

    DOEpatents

    Blair, Dianna S.; Freye, Gregory C.; Hughes, Robert C.; Martin, Stephen J.; Ricco, Antonio J.

    1993-01-01

    A method and apparatus for sensing a liquid-solid phase transition event is provided which comprises an acoustic plate mode detecting element placed in contact with a liquid or solid material which generates a high-frequency acoustic wave that is attenuated to an extent based on the physical state of the material is contact with the detecting element. The attenuation caused by the material in contact with the acoustic plate mode detecting element is used to determine the physical state of the material being detected. The method and device are particularly suited for detecting conditions such as the icing and deicing of wings of an aircraft. In another aspect of the present invention, a method is provided wherein the adhesion of a solid material to the detecting element can be measured using the apparatus of the invention.

  3. Combining Passive Thermography and Acoustic Emission for Large Area Fatigue Damage Growth Assessment of a Composite Structure

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Horne, Michael R.; Madaras, Eric I.; Burke, Eric R.

    2016-01-01

    Passive thermography and acoustic emission data were obtained for improved real time damage detection during fatigue loading. A strong positive correlation was demonstrated between acoustic energy event location and thermal heating, especially if the structure under load was nearing ultimate failure. An image processing routine was developed to map the acoustic emission data onto the thermal imagery. This required removing optical barrel distortion and angular rotation from the thermal data. The acoustic emission data were then mapped onto thermal data, revealing the cluster of acoustic emission event locations around the thermal signatures of interest. By combining both techniques, progression of damage growth is confirmed and areas of failure are identified. This technology provides improved real time inspections of advanced composite structures during fatigue testing.Keywords: Thermal nondestructive evaluation, fatigue damage detection, aerospace composite inspection, acoustic emission, passive thermography

  4. Apparatus for production of ultrapure amorphous metals utilizing acoustic cooling

    NASA Technical Reports Server (NTRS)

    Lee, M. C. (Inventor)

    1985-01-01

    Amorphous metals are produced by forming a molten unit of metal and deploying the unit into a bidirectional acoustical levitating field or by dropping the unit through a spheroidizing zone, a slow quenching zone, and a fast quenching zone in which the sphere is rapidly cooled by a bidirectional jet stream created in the standing acoustic wave field produced between a half cylindrical acoustic driver and a focal reflector or a curved driver and a reflector. The cooling rate can be further augmented first by a cryogenic liquid collar and secondly by a cryogenic liquid jacket surrounding a drop tower. The molten unit is quenched to an amorphous solid which can survive impact in a unit collector or is retrieved by a vacuum chuck.

  5. Fatigue features study on the crankshaft material of 42CrMo steel using acoustic emission

    NASA Astrophysics Data System (ADS)

    Shi, Yue; Dong, Lihong; Wang, Haidou; Li, Guolu; Liu, Shenshui

    2016-09-01

    Crankshaft is regarded as an important component of engines, and it is an important application of remanufacturing because of its high added value. However, the fatigue failure research of remanufactured crankshaft is still in its primary stage. Thus, monitoring and investigating the fatigue failure of the remanufacturing crankshaft is crucial. In this paper, acoustic emission (AE) technology and machine vision are used to monitor the four-point bending fatigue of 42CrMo, which is the material of crankshaft. The specimens are divided into two categories, namely, pre-existing crack and non-preexisting crack, which simulate the crankshaft and crankshaft blank, respectively. The analysis methods of parameter-based AE techniques, wavelet transform (WT) and SEM analysis are combined to identify the stage of fatigue failure. The stage of fatigue failure is the basis of using AE technology in the field of remanufacturing crankshafts. The experiment results show that the fatigue crack propagation style is a transgranular fracture and the fracture is a brittle fracture. The difference mainly depends on the form of crack initiation. Various AE signals are detected by parameter analysis method. Wavelet threshold denoising and WT are combined to extract the spectral features of AE signals at different fatigue failure stages.

  6. Dual-temperature acoustic levitation and sample transport apparatus

    NASA Technical Reports Server (NTRS)

    Trinh, E.; Robey, J.; Jacobi, N.; Wang, T.

    1986-01-01

    The properties of a dual-temperature resonant chamber to be used for acoustical levitation and positioning have been theoretically and experimentally studied. The predictions of a first-order dissipationless treatment of the generalized wave equation for an inhomogeneous medium are in close agreement with experimental results for the temperature dependence of the resonant mode spectrum and the acoustic pressure distribution, although the measured magnitude of the pressure variations does not correlate well with the calculated one. Ground-based levitation of low-density samples has been demonstrated at 800 C, where steady-state forces up to 700 dyn were generated.

  7. Quantitative Assessment of Fatigue Damage Accumulation in Wavy Slip Metals from Acoustic Harmonic Generation

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.

    2006-01-01

    A comprehensive, analytical treatment is presented of the microelastic-plastic nonlinearities resulting from the interaction of a stress perturbation with dislocation substructures (veins and persistent slip bands) and cracks that evolve during high-cycle fatigue of wavy slip metals. The nonlinear interaction is quantified by a material (acoustic) nonlinearity parameter beta extracted from acoustic harmonic generation measurements. The contribution to beta from the substructures is obtained from the analysis of Cantrell [Cantrell, J. H., 2004, Proc. R. Soc. London A, 460, 757]. The contribution to beta from cracks is obtained by applying the Paris law for crack propagation to the Nazarov-Sutin crack nonlinearity equation [Nazarov, V. E., and Sutin, A. M., 1997, J. Acoust. Soc. Am. 102, 3349]. The nonlinearity parameter resulting from the two contributions is predicted to increase monotonically by hundreds of percent during fatigue from the virgin state to fracture. The increase in beta during the first 80-90 percent of fatigue life is dominated by the evolution of dislocation substructures, while the last 10-20 percent is dominated by crack growth. The model is applied to the fatigue of aluminium alloy 2024-T4 in stress-controlled loading at 276MPa for which experimental data are reported. The agreement between theory and experiment is excellent.

  8. Monitoring of Temperature Fatigue Failure Mechanism for Polyvinyl Alcohol Fiber Concrete Using Acoustic Emission Sensors

    PubMed Central

    Li, Dongsheng; Cao, Hai

    2012-01-01

    The applicability of acoustic emission (AE) techniques to monitor the mechanism of evolution of polyvinyl alcohol (PVA) fiber concrete damage under temperature fatigue loading is investigated. Using the temperature fatigue test, real-time AE monitoring data of PVA fiber concrete is achieved. Based on the AE signal characteristics of the whole test process and comparison of AE signals of PVA fiber concretes with different fiber contents, the damage evolution process of PVA fiber concrete is analyzed. Finally, a qualitative evaluation of the damage degree is obtained using the kurtosis index and b-value of AE characteristic parameters. The results obtained using both methods are discussed. PMID:23012555

  9. Prediction of low-cycle fatigue-life by acoustic emission—2: 7075-T6 aluminum alloy

    SciTech Connect

    Baram, J.; Rosen, M.

    1981-01-01

    Low-cycle fatigue tests were conducted by tension-compression until rupture, on a 2024-T3 aluminum alloy sheet. Initial crack sizes and orientations in the fatigue specimens were found to be randomly distributed. Acoustic emission was continuously monitored during the tests. Every few hundred cycles, the acoustic signal having the highest peak-amplitude, was recorded as an extremal event for the elapsed period. This high peak-amplitude is related to a fast crack propagation rate through a phenomenological relationship. The extremal peakamplitudes are shown by an ordered statistics treatment, to be extremally distributed. The statistical treatment enables the prediction of the number of cycles left until failure. Predictions performed a-posteriori based on results gained early in each fatigue test are in good agreement with actual fatigue lives. The amplitude distribution analysis of the acoustic signals emitted during cyclic stress appears to be a promising nondestructive method of predicting fatigue life.

  10. Acoustic Correlates of Fatigue in Laryngeal Muscles: Findings for a Criterion-Based Prevention of Acquired Voice Pathologies

    ERIC Educational Resources Information Center

    Boucher, Victor J.

    2008-01-01

    Purpose: The objective was to identify acoustic correlates of laryngeal muscle fatigue in conditions of vocal effort. Method: In a previous study, a technique of electromyography (EMG) served to define physiological signs of "voice fatigue" in laryngeal muscles involved in voicing. These signs correspond to spectral changes in contraction…

  11. The L-Z complexity of exercise-induced muscle fatigue based on acoustic myographye

    NASA Astrophysics Data System (ADS)

    Yijian, Min; Xinyuan, Liu; Tingting, Wang

    2014-01-01

    The mechanism of exercise fatigue was investigated during exercise using L-Z complexity of non-linear analysis. Muscle fatigue was induced in the sitting position by lifting the heel under a load. An acoustic myogram of the gastrocnemius was obtained until exhaustion. The different modes of the speed responses were calculated using the L-Z complexity method, which analyzes muscle fibers participation, while the exercise is in progress. The L-Z complexity decreased incrementally with decreases in muscle strength, reaching a minimum value when the muscle was exhausted. Our data indicate that the L-Z complexity method is easy to use and effective at revealing the dynamic characteristics and variations of exercise fatigue. This method could be used to monitor sports training.

  12. Method and apparatus for measuring surface changes, in porous materials, using multiple differently-configured acoustic sensors

    DOEpatents

    Hietala, Susan Leslie; Hietala, Vincent Mark; Tigges, Chris Phillip

    2001-01-01

    A method and apparatus for measuring surface changes, such as mass uptake at various pressures, in a thin-film material, in particular porous membranes, using multiple differently-configured acoustic sensors.

  13. Acoustic study of dislocation rearrangement at later stages of fatigue: Noncontact prediction of remaining life

    NASA Astrophysics Data System (ADS)

    Ogi, Hirotsugu; Minami, Yoshikiyo; Hirao, Masahiko

    2002-02-01

    This study is devoted to clarifying the mechanism of the surface-shear-wave attenuation peak observed during rotating bending fatigue of carbon steels. We have developed electromagnetic acoustic resonance to make a contactless monitoring of the attenuation throughout the fatigue test. The attenuation peak occurs at a fixed fraction to lifetime, being independent of the bending stress (0.49-1.20 of the yield stresses) and the carbon content (0.22-0.45 mass %). Low-temperature heat treatment reduces the peak attenuation back to the previous value, which indicates a dominant contribution of dislocations. Microstructure observations with transmission electron microscopy, surface crack study with replicas and the acoustic measurements show that a large-scale change occurs in the dislocation structure (persistent slip bands to cells) at the attenuation peak and that it is triggered by the inward growth of cracks. This change is completed in a short time, a few percent of the total lifetime. The acoustic-resonance technique can be an important means for the exact prediction of the remaining life of fatigued steels.

  14. Fatigue and fracture assessment of cracks in steel elements using acoustic emission

    NASA Astrophysics Data System (ADS)

    Nemati, Navid; Metrovich, Brian; Nanni, Antonio

    2011-04-01

    Single edge notches provide a very well defined load and fatigue crack size and shape environment for estimation of the stress intensity factor K, which is not found in welded elements. ASTM SE(T) specimens do not appear to provide ideal boundary conditions for proper recording of acoustic wave propagation and crack growth behavior observed in steel bridges, but do provide standard fatigue crack growth rate data. A modified versions of the SE(T) specimen has been examined to provide small scale specimens with improved acoustic emission(AE) characteristics while still maintaining accuracy of fatigue crack growth rate (da/dN) versus stress intensity factor (ΔK). The specimens intend to represent a steel beam flange subjected to pure tension, with a surface crack growing transverse to a uniform stress field. Fatigue test is conducted at low R ratio. Analytical and numerical studies of stress intensity factor are developed for single edge notch test specimens consistent with the experimental program. ABAQUS finite element software is utilized for stress analysis of crack tips. Analytical, experimental and numerical analysis were compared to assess the abilities of AE to capture a growing crack.

  15. Acoustic emission and fatigue damage induced in plasma-sprayed hydroxyapatite coating layers.

    PubMed

    Laonapakul, Teerawat; Otsuka, Yuichi; Nimkerdphol, Achariya Rakngarm; Mutoh, Yoshiharu

    2012-04-01

    In order to improve the adhesive strength of hydroxyapatite (HAp) coatings, grit blasting with Al(2)O(3) powder and then wet blasting with HAp/Ti mixed powders was carried out on a commercially pure Ti (cp-Ti) substrate. Subsequently, an HAp/Ti bond coat layer and HAp top coat layer were deposited by plasma spraying. Fatigue tests of the HAp-coated specimens were carried out under four-point bending. Acoustic emission (AE) signals during the entire fatigue test were monitored to investigate the fatigue cracking behavior of the HAp-coated specimens. The HAp-coated specimens could survive up to 10(7) cycles without spallation of the HAp coating layers at the stress amplitude of 120 MPa. The HAp-coated specimens without HAp/Ti bond coat layer showed shorter fatigue life and easy crack nucleation compared to the HAp-coated specimens with HAp/Ti bond coat layer. The delamination and spallation of the HAp top coat with HAp/Ti bond coat on cp-Ti was not observed until the crack propagated into the cp-Ti during the final fracture stage of the fatigue cycle. Therefore, the HAp/Ti bond coat layer was found to greatly improve the fatigue damage resistance of the HAp coating layer. Three stages of the fatigue failure behavior of the HAp top coat with HAp/Ti bond coat on a cp-Ti substrate can be clearly estimated by the AE monitoring technique. These stages are cracks nucleating and propagating in the coating layer, cracks propagating in the substrate, and cracks propagating unstably to final fracture.

  16. Acoustic emission classification for failure prediction due to mechanical fatigue

    NASA Astrophysics Data System (ADS)

    Emamian, Vahid; Kaveh, Mostafa; Tewfik, Ahmed H.

    2000-06-01

    Acoustic Emission signals (AE), generated by the formation and growth of micro-cracks in metal components, have the potential for use in mechanical fault detection in monitoring complex- shaped components in machinery including helicopters and aircraft. A major challenge for an AE-based fault detection algorithm is to distinguish crack-related AE signals from other interfering transient signals, such as fretting-related AE signals and electromagnetic transients. Although under a controlled laboratory environment we have fewer interference sources, there are other undesired sources which have to be considered. In this paper, we present some methods, which make their decision based on the features extracted from time-delay and joint time-frequency components by means of a Self- Organizing Map (SOM) neural network using experimental data collected in a laboratory by colleagues at the Georgia Institute of Technology.

  17. Monitoring Thermal Fatigue Damage In Nuclear Power Plant Materials Using Acoustic Emission

    SciTech Connect

    Meyer, Ryan M.; Ramuhalli, Pradeep; Watson, Bruce E.; Pitman, Stan G.; Roosendaal, Timothy J.; Bond, Leonard J.

    2012-04-26

    Proactive aging management of nuclear power plant passive components requires technologies to enable monitoring and accurate quantification of material condition at early stages of degradation (i.e., pre-macrocrack). Acoustic emission (AE) is well-suited to continuous monitoring of component degradation and is proposed as a method to monitor degradation during accelerated thermal fatigue tests. A key consideration is the ability to separate degradation responses from external sources such as water spray induced during thermal fatigue testing. Water spray provides a significant background of acoustic signals, which can overwhelm AE signals caused by degradation. Analysis of AE signal frequency and energy is proposed in this work as a means for separating degradation signals from background sources. Encouraging results were obtained by applying both frequency and energy filters to preliminary data. The analysis of signals filtered using frequency and energy provides signatures exhibiting several characteristics that are consistent with degradation accumulation in materials. Future work is planned to enable verification of the efficacy of AE for thermal fatigue crack initiation detection. While the emphasis has been placed on the use of AE for crack initiation detection during accelerated aging tests, this work also has implications with respect to the use of AE as a primary tool for early degradation monitoring in nuclear power plant materials. The development of NDE tools for characterization of aging in materials can also benefit from the use of a technology such as AE which can continuously monitor and detect crack initiation during accelerated aging tests.

  18. Fatigue

    MedlinePlus

    ... to help you find out what's causing your fatigue and recommend ways to relieve it. Fatigue itself is not a disease. Medical problems, treatments, and personal habits can add to fatigue. These include Taking certain medicines, such as antidepressants, ...

  19. Acoustic-wave sensor apparatus for analyzing a petroleum-based composition and sensing solidification of constituents therein

    DOEpatents

    Spates, J.J.; Martin, S.J.; Mansure, A.J.

    1997-08-26

    An acoustic-wave sensor apparatus and method are disclosed. The apparatus for analyzing a normally liquid petroleum-based composition includes at least one acoustic-wave device in contact with the petroleum-based composition for sensing or detecting the presence of constituents (e.g. paraffins or petroleum waxes) therein which solidify upon cooling of the petroleum-based composition below a cloud-point temperature. The acoustic-wave device can be a thickness-shear-mode device (also termed a quartz crystal microbalance), a surface-acoustic-wave device, an acoustic-plate-mode device or a flexural plate-wave device. Embodiments of the present invention can be used for measuring a cloud point, a pour point and/or a freeze point of the petroleum-based composition, and for determining a temperature characteristic of each point. Furthermore, measurements with the acoustic-wave sensor apparatus can be made off-line by using a sample having a particular petroleum-based composition; or in-situ with the petroleum-based composition contained within a pipeline or storage tank. The acoustic-wave sensor apparatus has uses in many different petroleum technology areas, including the recovery, transport, storage, refining and use of petroleum and petroleum-based products. 7 figs.

  20. Acoustic-wave sensor apparatus for analyzing a petroleum-based composition and sensing solidification of constituents therein

    DOEpatents

    Spates, James J.; Martin, Stephen J.; Mansure, Arthur J.

    1997-01-01

    An acoustic-wave sensor apparatus and method. The apparatus for analyzing a normally liquid petroleum-based composition includes at least one acoustic-wave device in contact with the petroleum-based composition for sensing or detecting the presence of constituents (e.g. paraffins or petroleum waxes) therein which solidify upon cooling of the petroleum-based composition below a cloud-point temperature. The acoustic-wave device can be a thickness-shear-mode device (also termed a quartz crystal mircrobalance), a surface-acoustic-wave device, an acoustic-plate-mode device or a flexural plate-wave device. Embodiments of the present invention can be used for measuring a cloud point, a pour point and/or a freeze point of the petroleum-based composition, and for determining a temperature characteristic of each point. Furthermore, measurements with the acoustic-wave sensor apparatus can be made off-line by using a sample having a particular petroleum-based composition; or in-situ with the petroleum-based composition contained within a pipeline or storage tank. The acoustic-wave sensor apparatus has uses in many different petroleum technology areas, including the recover transport, storage, refining and use of petroleum and petroleum-based products.

  1. Combining passive thermography and acoustic emission for large area fatigue damage growth assessment of a composite structure

    NASA Astrophysics Data System (ADS)

    Zalameda, Joseph N.; Horne, Michael R.; Madaras, Eric I.; Burke, Eric R.

    2016-05-01

    Passive thermography and acoustic emission data were obtained for improved real time damage detection during fatigue loading. A strong positive correlation was demonstrated between acoustic energy event location and thermal heating, especially if the structure under load was nearing ultimate failure. An image processing routine was developed to map the acoustic emission data onto the thermal imagery. This required removing optical barrel distortion and angular rotation from the thermal data. The acoustic emission data were then mapped onto thermal data, revealing the cluster of acoustic emission event locations around the thermal signatures of interest. By combining both techniques, progression of damage growth is confirmed and areas of failure are identified. This technology provides improved real time inspections of advanced composite structures during fatigue testing.

  2. Method and apparatus for detecting internal structures of bulk objects using acoustic imaging

    DOEpatents

    Deason, Vance A.; Telschow, Kenneth L.

    2002-01-01

    Apparatus for producing an acoustic image of an object according to the present invention may comprise an excitation source for vibrating the object to produce at least one acoustic wave therein. The acoustic wave results in the formation of at least one surface displacement on the surface of the object. A light source produces an optical object wavefront and an optical reference wavefront and directs the optical object wavefront toward the surface of the object to produce a modulated optical object wavefront. A modulator operatively associated with the optical reference wavefront modulates the optical reference wavefront in synchronization with the acoustic wave to produce a modulated optical reference wavefront. A sensing medium positioned to receive the modulated optical object wavefront and the modulated optical reference wavefront combines the modulated optical object and reference wavefronts to produce an image related to the surface displacement on the surface of the object. A detector detects the image related to the surface displacement produced by the sensing medium. A processing system operatively associated with the detector constructs an acoustic image of interior features of the object based on the phase and amplitude of the surface displacement on the surface of the object.

  3. Remote monitoring and prognosis of fatigue cracking in steel bridges with acoustic emission

    NASA Astrophysics Data System (ADS)

    Yu, Jianguo Peter; Ziehl, Paul; Pollock, Adrian

    2011-04-01

    Acoustic emission (AE) monitoring is desirable to nondestructively detect fatigue damage in steel bridges. Investigations of the relationship between AE signals and crack growth behavior are of paramount importance prior to the widespread application of passive piezoelectric sensing for monitoring of fatigue crack propagation in steel bridges. Tests have been performed to detect AE from fatigue cracks in A572G50 steel. Noise induced AE signals were filtered based on friction emission tests, loading pattern, and a combined approach involving Swansong II filters and investigation of waveforms. The filtering methods based on friction emission tests and load pattern are of interest to the field evaluation using sparse datasets. The combined approach is suitable for data filtering and interpretation of actual field tests. The pattern recognition program NOESIS (Envirocoustics) was utilized for the evaluation of AE data quality. AE parameters are associated with crack length, crack growth rate, maximum stress intensity and stress intensity range. It is shown that AE hits, counts, absolute energy, and signal strength are able to provide warnings at the critical cracking level where cracking progresses from stage II (stable propagation) to stage III (unstable propagation which may result in failure). Absolute energy rate and signal strength rate may be better than count rate to assess the remaining fatigue life of inservice steel bridges.

  4. Apparatus and method for acoustic monitoring of steam quality and flow

    DOEpatents

    Sinha, Dipen N.; Pantea, Cristian

    2016-09-13

    An apparatus and method for noninvasively monitoring steam quality and flow and in pipes or conduits bearing flowing steam, are described. By measuring the acoustic vibrations generated in steam-carrying conduits by the flowing steam either by direct contact with the pipe or remotely thereto, converting the measured acoustic vibrations into a frequency spectrum characteristic of the natural resonance vibrations of the pipe, and monitoring the amplitude and/or the frequency of one or more chosen resonance frequencies, changes in the steam quality in the pipe are determined. The steam flow rate and the steam quality are inversely related, and changes in the steam flow rate are calculated from changes in the steam quality once suitable calibration curves are obtained.

  5. Acoustic harmonic generation from fatigue-generated dislocation substructures in copper single crystals

    NASA Astrophysics Data System (ADS)

    Apple, T. M.; Cantrell, J. H.; Amaro, C. M.; Mayer, C. R.; Yost, W. T.; Agnew, S. R.; Howe, J. M.

    2013-07-01

    Dislocations generated during cyclic loading of metals self-organize into substructures that produce substantial changes in the nonlinear response. The nonlinearity is quantified by the material nonlinearity parameter ? extracted from acoustic harmonic generation measurements. Measurements of ? on copper single crystals oriented for single-slip ([1 2 3] loading axis) and fatigued in plastic strain control are compared to calculations of ? obtained from the Cantrell model for which measured values of model parameters associated with the substructures are required. Transmission electron microscopy measurements of the volume fractions of veins and persistent slip bands, dislocation loop lengths, dipole heights and the densities of primary and secondary dislocations in the fatigue-generated substructures are obtained for input into the model calculations. The model predictions agree with the values observed experimentally. In particular, the experimental data show an increase in ? proportional to ? where ? is the cumulative plastic strain and m is 0.7 and 0.4, respectively, for acoustic wave propagation along the ? and ? crystal axes. Such dependence is consistent with the Cantrell model and at variance with models, based on assumed variations in the third-order elastic constants, which predict an exponential dependence on ? .

  6. Effects of speech style, room acoustics, and vocal fatigue on vocal effort.

    PubMed

    Bottalico, Pasquale; Graetzer, Simone; Hunter, Eric J

    2016-05-01

    Vocal effort is a physiological measure that accounts for changes in voice production as vocal loading increases. It has been quantified in terms of sound pressure level (SPL). This study investigates how vocal effort is affected by speaking style, room acoustics, and short-term vocal fatigue. Twenty subjects were recorded while reading a text at normal and loud volumes in anechoic, semi-reverberant, and reverberant rooms in the presence of classroom babble noise. The acoustics in each environment were modified by creating a strong first reflection in the talker position. After each task, the subjects answered questions addressing their perception of the vocal effort, comfort, control, and clarity of their own voice. Variation in SPL for each subject was measured per task. It was found that SPL and self-reported effort increased in the loud style and decreased when the reflective panels were present and when reverberation time increased. Self-reported comfort and control decreased in the loud style, while self-reported clarity increased when panels were present. The lowest magnitude of vocal fatigue was experienced in the semi-reverberant room. The results indicate that early reflections may be used to reduce vocal effort without modifying reverberation time.

  7. Acoustic Emission and Guided Wave Monitoring of Fatigue Crack Growth on a Full Pipe Specimen

    SciTech Connect

    Meyer, Ryan M.; Cumblidge, Stephen E.; Ramuhalli, Pradeep; Watson, Bruce E.; Doctor, Steven R.; Bond, Leonard J.

    2011-05-06

    Continuous on-line monitoring of active and passive systems, structures and components in nuclear power plants will be critical to extending the lifetimes of nuclear power plants in the US beyond 60 years. Acoustic emission and guided ultrasonic waves are two tools for continuously monitoring passive systems, structures and components within nuclear power plants and are the focus of this study. These tools are used to monitor fatigue damage induced in a SA 312 TP304 stainless steel pipe specimen. The results of acoustic emission monitoring indicate that crack propagation signals were not directly detected. However, acoustic emission monitoring exposed crack formation prior to visual confirmation through the detection of signals caused by crack closure friction. The results of guided ultrasonic wave monitoring indicate that this technology is sensitive to the presence and size of cracks. The sensitivity and complexity of GUW signals is observed to vary with respect to signal frequency and path traveled by the guided ultrasonic wave relative to the crack orientation.

  8. Control of Thermal Deflection, Panel Flutter and Acoustic Fatigue at Elevated Temperatures Using Shape Memory Alloys

    NASA Technical Reports Server (NTRS)

    Mei, Chuh; Huang, Jen-Kuang

    1996-01-01

    The High Speed Civil Transport (HSCT) will have to be designed to withstand high aerodynamic load at supersonic speeds (panel flutter) and high acoustic load (acoustic or sonic fatigue) due to fluctuating boundary layer or jet engine acoustic pressure. The thermal deflection of the skin panels will also alter the vehicle's configuration, thus it may affect the aerodynamic characteristics of the vehicle and lead to poor performance. Shape memory alloys (SMA) have an unique ability to recover large strains completely when the alloy is heated above the characteristic transformation (austenite finish T(sub f)) temperature. The recovery stress and elastic modulus are both temperature dependent, and the recovery stress also depends on the initial strain. An innovative concept is to utilize the recovery stress by embedding the initially strained SMA wire in a graphite/epoxy composite laminated panel. The SMA wires are thus restrained and large inplane forces are induced in the panel at elevated temeperatures. By embedding SMA in composite panel, the panel becomes much stiffer at elevated temperatures. That is because the large tensile inplane forces induced in the panel from the SMA recovery stress. A stiffer panel would certainly yield smaller dynamic responses.

  9. Real-time monitoring of acoustic linear and nonlinear behavior of titanium alloys during low-cycle fatigue and high-cycle fatigue

    NASA Astrophysics Data System (ADS)

    Frouin, Jerome; Sathish, Shamachary; Na, Jeong K.

    2000-05-01

    An in-situ technique to measure sound velocity, ultrasonic attenuation and acoustic nonlinear property has been developed for characterization and early detection of fatigue damage in aerospace materials. For this purpose we have developed a computer software and measurement technique including hardware for the automation of the measurement. New transducer holder and special grips are designed. The automation has allowed us to test the long-term stability of the electronics over a period of time and so proof of the linearity of the system. Real-time monitoring of the material nonlinearity has been performed on dog-bone specimens from zero fatigue all the way to the final fracture under low-cycle fatigue test condition (LCF) and high-cycle test condition (HCF). Real-time health monitoring of the material can greatly contribute to the understanding of material behavior under cyclic loading. Interpretation of the results show that correlation exist between the slope of the curve described by the material nonlinearity and the life of the component. This new methodology was developed with an objective to predict the initiation of fatigue microcracks, and to detect, in-situ fatigue crack initiation as well as to quantify early stages of fatigue damage.

  10. Problems Associated with Statistical Pattern Recognition of Acoustic Emission Signals in a Compact Tension Fatigue Specimen

    NASA Technical Reports Server (NTRS)

    Hinton, Yolanda L.

    1999-01-01

    Acoustic emission (AE) data were acquired during fatigue testing of an aluminum 2024-T4 compact tension specimen using a commercially available AE system. AE signals from crack extension were identified and separated from noise spikes, signals that reflected from the specimen edges, and signals that saturated the instrumentation. A commercially available software package was used to train a statistical pattern recognition system to classify the signals. The software trained a network to recognize signals with a 91-percent accuracy when compared with the researcher's interpretation of the data. Reasons for the discrepancies are examined and it is postulated that additional preprocessing of the AE data to focus on the extensional wave mode and eliminate other effects before training the pattern recognition system will result in increased accuracy.

  11. Method and apparatus for acoustically monitoring the flow of suspended solid particulate matter

    DOEpatents

    Roach, Paul D.; Raptis, Apostolos C.

    1982-01-01

    A method and apparatus for monitoring char flow in a coal gasifier system cludes flow monitor circuits which measure acoustic attenuation caused by the presence of char in a char line and provide a char flow/no flow indication and an indication of relative char density. The flow monitor circuits compute the ratio of signals in two frequency bands, a first frequency band representative of background noise, and a second higher frequency band in which background noise is attenuated by the presence of char. Since the second frequency band contains higher frequencies, the ratio can be used to provide a flow/no flow indication. The second band can also be selected so that attenuation is monotonically related to particle concentration, providing a quantitative measure of char concentration.

  12. Fatigue crack growth monitoring of idealized gearbox spline component using acoustic emission

    NASA Astrophysics Data System (ADS)

    Zhang, Lu; Ozevin, Didem; Hardman, William; Kessler, Seth; Timmons, Alan

    2016-04-01

    The spline component of gearbox structure is a non-redundant element that requires early detection of flaws for preventing catastrophic failures. The acoustic emission (AE) method is a direct way of detecting active flaws; however, the method suffers from the influence of background noise and location/sensor based pattern recognition method. It is important to identify the source mechanism and adapt it to different test conditions and sensors. In this paper, the fatigue crack growth of a notched and flattened gearbox spline component is monitored using the AE method in a laboratory environment. The test sample has the major details of the spline component on a flattened geometry. The AE data is continuously collected together with strain gauges strategically positions on the structure. The fatigue test characteristics are 4 Hz frequency and 0.1 as the ratio of minimum to maximum loading in tensile regime. It is observed that there are significant amount of continuous emissions released from the notch tip due to the formation of plastic deformation and slow crack growth. The frequency spectra of continuous emissions and burst emissions are compared to understand the difference of sudden crack growth and gradual crack growth. The predicted crack growth rate is compared with the AE data using the cumulative AE events at the notch tip. The source mechanism of sudden crack growth is obtained solving the inverse mathematical problem from output signal to input signal. The spline component of gearbox structure is a non-redundant element that requires early detection of flaws for preventing catastrophic failures. In this paper, the fatigue crack growth of a notched and flattened gearbox spline component is monitored using the AE method The AE data is continuously collected together with strain gauges. There are significant amount of continuous emissions released from the notch tip due to the formation of plastic deformation and slow crack growth. The source mechanism of

  13. Acoustic teaching apparatus before 1929 at the Case School of Applied Science

    NASA Astrophysics Data System (ADS)

    Hoekje, Peter L.; Fickinger, William

    2001-05-01

    The acoustics apparatus found in the Physics Department of the Case School of Applied Science in the first decades of the 20th century included many items common to other acoustical teaching laboratories, such as organ pipes, tuning forks, Helmholtz resonators, sirens, and manometric flame sound analyzers. The European instrument makers Rudolf Koenig and Max Kohl supplied much of this. Equipment built at Case included the phonodeik, which Dayton C. Miller designed in 1908, and the waveform synthesizer. Miller supplied detailed descriptions of the operations of all this equipment in papers and books. In the phonodeik (to show sound), sound deflects a thin glass diaphragm, which by a silk thread turns a mirror on an axle, causing a spot of light to move across film or a projection screen. A working model of the phonodeik has been reconstructed from pieces of two original ones, and will be demonstrated. Photographs of other extant instruments in the collection, and a selection from Millers lantern slides, will be displayed.

  14. Apparatus for real-time acoustic imaging of Rayleigh-Bénard convection

    SciTech Connect

    Kuehn, Kerry, K.

    2008-10-28

    We have successfully designed, built and tested an experimental apparatus which is capable of providing the first real-time ultrasound images of Rayleigh-B\\'{e}nard convection in optically opaque fluids confined to large aspect ratio experimental cells. The apparatus employs a modified version of a commercially available ultrasound camera to capture images (30 frames per second) of flow patterns in a fluid undergoing Rayleigh Bénard convection. The apparatus was validated by observing convection rolls in 5cSt polydimethylsiloxane (PDMS) polymer fluid. Our first objective, after having built the apparatus, was to use it to study the sequence of transitions from diffusive to time--dependent heat transport in liquid mercury. The aim was to provide important information on pattern formation in the largely unexplored regime of very low Prandtl number fluids. Based on the theoretical stability diagram for liquid mercury, we anticipated that straight rolls should be stable over a range of Rayleigh numbers, between 1708 and approximately 1900. Though some of our power spectral densities were suggestive of the existence of weak convection, we have been unable to unambiguously visualize stable convection rolls above the theoretical onset of convection in liquid mercury. Currently, we are seeking ways to increase the sensitivity of our apparatus, such as (i) improving the acoustic impedance matching between our materials in the ultrasound path and (ii) reducing the noise level in our acoustic images due to turbulence and cavitation in the cooling fluids circulating above and below our experimental cell. If we are able to convincingly improve the sensitivity of our apparatus, and we still do not observe stable convection rolls in liquid mercury, then it may be the case that the theoretical stability diagram requires revision. In that case, either (i) straight rolls are not stable in a large aspect ratio cell at the Prandtl numbers associated with liquid mercury, or (ii) they

  15. Fatigue

    MedlinePlus

    Bennett RM. Fibromyalgia, chronic fatigue syndrome, and myofascial pain. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 274. Thames TA, Karrh ...

  16. Analytical modeling of contact acoustic nonlinearity of guided waves and its application to evaluating severity of fatigue damage

    NASA Astrophysics Data System (ADS)

    Wang, Kai; Su, Zhongqing

    2016-04-01

    Targeting quantitative estimate of fatigue damage, a dedicated analytical model was developed based on the modal decomposition method and the variational principle. The model well interprets the contact acoustic nonlinearity induced by a "breathing" crack in a two-dimensional scenario, and the nonlinear characteristics of guided ultrasonic waves (GUWs) (e.g., reflection, transmission, mode conversion and high-order generation) when GUWs traversing the crack. Based on the model, a second-order reflection index was defined. Using the index, a fatigue damage evaluation framework was established, showing demonstrated capacity of estimating the severity of fatigue damage in a quantitative manner. The approach, in principle, does not entail a benchmarking process against baseline signals pre-acquired from pristine counterparts. The results obtained using the analytical modeling were compared with those from finite element simulation, showing good coincidence. Limitations of the model were also discussed.

  17. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  18. Development of a New Apparatus for Investigating Acoustic Effects on Hydraulic Properties of Low-Permeability Geo-Materials

    NASA Astrophysics Data System (ADS)

    Nakajima, H.; Sawada, A.; Sugita, H.; Takeda, M.; Komai, T.; Zhang, M.

    2006-12-01

    feasibility of the EASD method and to obtain the fundamental but important knowledge for the design of this method, it is first necessary to understand the effects of acoustic wave application on pore water flow behavior. A new apparatus is developed to investigate the effects of acoustic wave on hydraulic properties of soil sample. This test apparatus enables to confine a cylindrical specimen under hydrostatic pressure conditions and to apply acoustic wave simultaneously. Preliminary results associated with the effects of acoustic wave frequency on changes of permeability of kaolin clay samples are illustrated in this report. A program investigating the effects of electricity and pore water chemistry on efficiency of decontamination using the same samples is also ongoing and briefly presented. The two strategies for enhancing the efficiency of remediation for low permeable soils will be combined in the near future

  19. Acoustic emission studies for characterization of fatigue crack growth behavior in HSLA steel

    NASA Astrophysics Data System (ADS)

    Kumar, Jalaj; Ahmad, S.; Mukhopadhyay, C. K.; Jayakumar, T.; Kumar, Vikas

    2016-01-01

    High strength low alloy (HSLA) steels are a group of low carbon steels and used in oil and gas pipelines, automotive components, offshore structures and shipbuilding. Fatigue crack growth (FCG) characteristics of a HSLA steel have been studied at two different stress ratios (R = 0.3 and 0.5). Acoustic emission (AE) signals generated during the FCG tests have been used to understand the FCG processes. The AE signals were captured by mounting two piezoelectric sensors on compact tension specimens in liner location configuration. The AE generated in stage II of the linear Paris region of FCG has been attributed to the presence of two sub-stages with two different slopes. The AE generated at higher values of stress intensity factor is found to be useful to identify the transition from stage II to stage III of the FCG. AE location analysis has provided support for increased damage at the crack tip for higher stress ratio. The peak stress intensity (Kmax) values at the crack tip have shown good correlation with the transitions from stage IIa to stage IIb and stage II to stage III of the FCG for the two stress ratios.

  20. Comparison of structural response and fatigue endurance of aircraft flap-like box structures subjected to acoustic loading.

    PubMed

    Xiao, Y; White, R G; Aglietti, G S

    2005-05-01

    The results of an extensive test program to characterize the behavior of typical aircraft structures under acoustic loading and to establish their fatigue endurance are presented. The structures tested were the three flap-like box-type of structures. Each structure consisted of one flat (bottom) and one curved (top) stiffener stiffened skin panel, front, and rear spars, and ribs that divided the structures into three bays. The three structures, constructed from three different materials (aircraft standard aluminum alloy, Carbon Fibre Reinforced Plastic, and a Glass Fibre Metal Laminate, i.e., GLARE) had the same size and configuration, with only minor differences due to the use of different materials. A first set of acoustic tests with excitations of intensity ranging from 140 to 160 dB were carried out to obtain detailed data on the dynamic response of the three structures. The FE analysis of the structures is also briefly described and the results compared with the experimental data. The fatigue endurance of the structures was then determined using random acoustic excitation with an overall sound pressure level of 161 dB, and details of crack propagation are reported.

  1. An experimental study on resonance of oscillating air/vapor bubbles in water using a two-frequency acoustic apparatus

    NASA Astrophysics Data System (ADS)

    Ohsaka, K.

    2003-05-01

    A two-frequency acoustic apparatus is employed to study the growth behavior of vapor-saturated bubbles driven in a volumetric mode. A unique feature of the apparatus is its capability of trapping a bubble by an ultrasonic standing wave while independently driving it into oscillations by a second lower-frequency acoustic wave. It is observed that the growing vapor bubbles exhibit a periodic shape transition between the volumetric and shape modes due to resonant coupling. In order to explain this observation, we performed an experimental investigation on resonant coupling of air bubbles and obtained the following results: First, the induced shape oscillations are actually a mixed mode that contains the volume component, thus, vapor bubbles can grow while they exhibit shape oscillations. Second, the acoustically levitated bubbles are deformed and therefore, degeneracy in resonant frequency is partially removed. As a result, the vapor bubbles exhibit the shape oscillations in both the axisymmetric mode and asymmetric (three-dimensional) modes. Nonlinear effects in addition to the frequency shift and split due to deformation creates overlapping of the coupling ranges for different modes, which leads to the continuous shape oscillations above a certain bubble radius as the bubble grows.

  2. Sensor apparatus

    DOEpatents

    Deason, Vance A [Idaho Falls, ID; Telschow, Kenneth L [Idaho Falls, ID

    2009-12-22

    A sensor apparatus and method for detecting an environmental factor is shown that includes an acoustic device that has a characteristic resonant vibrational frequency and mode pattern when exposed to a source of acoustic energy and, futher, when exposed to an environmental factor, produces a different resonant vibrational frequency and/or mode pattern when exposed to the same source of acoustic energy.

  3. Acoustic fatigue life prediction for nonlinear structures with multiple resonant modes

    NASA Technical Reports Server (NTRS)

    Miles, R. N.

    1992-01-01

    This report documents an effort to develop practical and accurate methods for estimating the fatigue lives of complex aerospace structures subjected to intense random excitations. The emphasis of the current program is to construct analytical schemes for performing fatigue life estimates for structures that exhibit nonlinear vibration behavior and that have numerous resonant modes contributing to the response.

  4. Detecting vocal fatigue in student singers using acoustic measures of mean fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio

    NASA Astrophysics Data System (ADS)

    Sisakun, Siphan

    2000-12-01

    The purpose of this study is to explore the ability of four acoustic parameters, mean fundamental frequency, jitter, shimmer, and harmonics-to-noise ratio, to detect vocal fatigue in student singers. The participants are 15 voice students, who perform two distinct tasks, data collection task and vocal fatiguing task. The data collection task includes the sustained vowel /a/, reading a standard passage, and self-rate on a vocal fatigue form. The vocal fatiguing task is the vocal practice of musical scores for a total of 45 minutes. The four acoustic parameters are extracted using the software EZVoicePlus. The data analyses are performed to answer eight research questions. The first four questions relate to correlations of the self-rating scale and each of the four parameters. The next four research questions relate to differences in the parameters over time using one-factor repeated measures analysis of variance (ANOVA). The result yields a proposed acoustic profile of vocal fatigue in student singers. This profile is characterized by increased fundamental frequency; slightly decreased jitter; slightly decreased shimmer; and slightly increased harmonics-to-noise ratio. The proposed profile requires further investigation.

  5. Methods and apparatus for non-acoustic speech characterization and recognition

    SciTech Connect

    Holzrichter, J.F.

    1999-12-21

    By simultaneously recording EM wave reflections and acoustic speech information, the positions and velocities of the speech organs as speech is articulated can be defined for each acoustic speech unit. Well defined time frames and feature vectors describing the speech, to the degree required, can be formed. Such feature vectors can uniquely characterize the speech unit being articulated each time frame. The onset of speech, rejection of external noise, vocalized pitch periods, articulator conditions, accurate timing, the identification of the speaker, acoustic speech unit recognition, and organ mechanical parameters can be determined.

  6. Methods and apparatus for non-acoustic speech characterization and recognition

    DOEpatents

    Holzrichter, John F.

    1999-01-01

    By simultaneously recording EM wave reflections and acoustic speech information, the positions and velocities of the speech organs as speech is articulated can be defined for each acoustic speech unit. Well defined time frames and feature vectors describing the speech, to the degree required, can be formed. Such feature vectors can uniquely characterize the speech unit being articulated each time frame. The onset of speech, rejection of external noise, vocalized pitch periods, articulator conditions, accurate timing, the identification of the speaker, acoustic speech unit recognition, and organ mechanical parameters can be determined.

  7. Method and apparatus for separating mixtures of gases using an acoustic wave

    DOEpatents

    Geller, Drew A.; Swift, Gregory W.; Backhaus, Scott N.

    2004-05-11

    A thermoacoustic device separates a mixture of gases. An elongated duct is provided with first and second ends and has a length that is greater than the wavelength of sound in the mixture of gases at a selected frequency, and a diameter that is greater than a thermal penetration depth in the mixture of gases. A first acoustic source is located at the first end of the duct to generate acoustic power at the selected frequency. A plurality of side branch acoustic sources are spaced along the length of the duct and are configured to introduce acoustic power into the mixture of gases so that a first gas is concentrated at the first end of the duct and a second gas is concentrated at the second end of the duct.

  8. Acoustic Emission Investigation of Rolling/Sliding Contact Fatigue Failure of NiCr-Cr3C2 Coating

    NASA Astrophysics Data System (ADS)

    Guolu, Li; Zhonglin, Xu; Tianshun, Dong; Haidou, Wang; Jinhai, Liu; Jiajie, Kang

    2016-08-01

    NiCr-Cr3C2 coating was fabricated using supersonic plasma spraying technology. Subsequently, rolling/sliding contact fatigue (R/SCF) testing was carried out, using acoustic emission (AE) technology to monitor the failure process. The results showed that R/SCF consists of three failure modes, namely abrasion, spalling, and delamination. Abrasion is the main failure mode, but delamination is the most severe. The AE monitoring results indicated that the R/SCF failure process is composed of normal contact, crack initiation, crack propagation, and material removal stages. The frequency of each stage was analyzed by fast Fourier transform, revealing a peak frequency for each stage mainly distributed from 200 to 250 kHz.

  9. Acoustic Emission Investigation of Rolling/Sliding Contact Fatigue Failure of NiCr-Cr3C2 Coating

    NASA Astrophysics Data System (ADS)

    Guolu, Li; Zhonglin, Xu; Tianshun, Dong; Haidou, Wang; Jinhai, Liu; Jiajie, Kang

    2016-10-01

    NiCr-Cr3C2 coating was fabricated using supersonic plasma spraying technology. Subsequently, rolling/sliding contact fatigue (R/SCF) testing was carried out, using acoustic emission (AE) technology to monitor the failure process. The results showed that R/SCF consists of three failure modes, namely abrasion, spalling, and delamination. Abrasion is the main failure mode, but delamination is the most severe. The AE monitoring results indicated that the R/SCF failure process is composed of normal contact, crack initiation, crack propagation, and material removal stages. The frequency of each stage was analyzed by fast Fourier transform, revealing a peak frequency for each stage mainly distributed from 200 to 250 kHz.

  10. Acoustic travel time gauges for in-situ determination of pressure and temperature in multi-anvil apparatus

    SciTech Connect

    Wang, Xuebing; Chen, Ting; Qi, Xintong; Zou, Yongtao; Liebermann, Robert C.; Li, Baosheng; Kung, Jennifer; Yu, Tony; Wang, Yanbin

    2015-08-14

    In this study, we developed a new method for in-situ pressure determination in multi-anvil, high-pressure apparatus using an acoustic travel time approach within the framework of acoustoelasticity. The ultrasonic travel times of polycrystalline Al{sub 2}O{sub 3} were calibrated against NaCl pressure scale up to 15 GPa and 900 °C in a Kawai-type double-stage multi-anvil apparatus in conjunction with synchrotron X-radiation, thereby providing a convenient and reliable gauge for pressure determination at ambient and high temperatures. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point methods. Application of this new pressure gauge in an offline experiment revealed a remarkable agreement of the densities of coesite with those from the previous single crystal compression studies under hydrostatic conditions, thus providing strong validation for the current travel time pressure scale. The travel time approach not only can be used for continuous in-situ pressure determination at room temperature, high temperatures, during compression and decompression, but also bears a unique capability that none of the previous scales can deliver, i.e., simultaneous pressure and temperature determination with a high accuracy (±0.16 GPa in pressure and ±17 °C in temperature). Therefore, the new in-situ Al{sub 2}O{sub 3} pressure gauge is expected to enable new and expanded opportunities for offline laboratory studies of solid and liquid materials under high pressure and high temperature in multi-anvil apparatus.

  11. Fatigue-crack monitoring in-flight using acoustic emission - hardware, technique, and testing

    SciTech Connect

    Hutton, P.H.; Skorpik, J.R.; Lemon, D.K.

    1981-07-01

    The three programs described represent a logical evolutionary process toward effective flaw surveillance in aircraft using AE. The Macchi tests showed that an AE system can withstand extended in-flight service and collect meaningful information relative to fatigue crack growth at a single specific location. The MIrage aircraft work seeks to extend the methods demonstrated on the Macchi into a more complex circumstance. We are now attempting to detect and locate crack growth at any of twenty fastener locations in a relatively complex geometry. The DARPA pattern recognition program seeks to develop signal identification capability that would pave the way for general monitoring of aircraft structures using AE to detect fatigue crack growth. It appears that AE technology may be capable of enhancing aircraft safety assurance while reducing inspection requirements with the associated costs.

  12. Apparatus and method for non-contact, acoustic resonance determination of intraocular pressure

    DOEpatents

    Sinha, Dipen N.; Wray, William O.

    1994-01-01

    Apparatus and method for measuring intraocular pressure changes in an eye under investigation by detection of vibrational resonances therein. An ultrasonic transducer operating at its resonant frequency is amplitude modulated and swept over a range of audio frequencies in which human eyes will resonate. The output therefrom is focused onto the eye under investigation, and the resonant vibrations of the eye observed using a fiber-optic reflection vibration sensor. Since the resonant frequency of the eye is dependent on the pressure therein, changes in intraocular pressure may readily be determined after a baseline pressure is established.

  13. Apparatus and method for non-contact, acoustic resonance determination of intraocular pressure

    DOEpatents

    Sinha, D.N.; Wray, W.O.

    1994-12-27

    The apparatus and method for measuring intraocular pressure changes in an eye under investigation by detection of vibrational resonances therein. An ultrasonic transducer operating at its resonant frequency is amplitude modulated and swept over a range of audio frequencies in which human eyes will resonate. The output therefrom is focused onto the eye under investigation, and the resonant vibrations of the eye observed using a fiber-optic reflection vibration sensor. Since the resonant frequency of the eye is dependent on the pressure therein, changes in intraocular pressure may readily be determined after a baseline pressure is established. 3 figures.

  14. Passive acoustic detection of closed-circuit underwater breathing apparatus in an operational port environment.

    PubMed

    Fillinger, L; Hunter, A J; Zampolli, M; Clarijs, M C

    2012-10-01

    Divers constitute a potential threat to waterside infrastructures. Active diver detection sonars are available commercially but present some shortcomings, particularly in highly reverberant environments. This has led to research on passive sonar for diver detection. Passive detection of open-circuit UBA (underwater breathing apparatus) has been demonstrated. This letter reports on the detection of a diver wearing closed-circuit UBA (rebreather) in an operational harbor. Beamforming is applied to a passive array of 10 hydrophones in a pseudo-random linear arrangement. Experimental results are presented demonstrating detection of the rebreather at ranges up to 120 m and are validated by GPS ground truth.

  15. Non-Destructive Evaluation Method and Apparatus for Measuring Acoustic Material Nonlinearity

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, John H. (Inventor)

    2002-01-01

    An acoustic non-linearity parameter (beta) measurement method and system for Non-Destructive Evaluation (NDE) of materials and structural members obviates the need for electronic calibration of the measuring equipment. Unlike known substitutional measuring techniques requiring elaborate calibration procedures, the electrical outputs of the capacitive detector of a sample with known beta and the test sample of unknown beta are compared to determine the unknown beta. In order to provide the necessary stability of the present-inventive reference-based approach, the bandpass filters of the measurement system are maintained in a temperature-controlled environment, and the line voltage supplied to said amplifiers is well-regulated.

  16. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus

    NASA Astrophysics Data System (ADS)

    Yan, Zhaoli; Chen, Bin; Tian, Hao; Cheng, Xiaobin; Yang, Jun

    2015-12-01

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10-4 during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  17. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus

    SciTech Connect

    Yan, Zhaoli Tian, Hao; Cheng, Xiaobin; Yang, Jun; Chen, Bin

    2015-12-15

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10{sup −4} during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  18. Acoustic detection of cracks in the anvil of a large-volume cubic high-pressure apparatus.

    PubMed

    Yan, Zhaoli; Chen, Bin; Tian, Hao; Cheng, Xiaobin; Yang, Jun

    2015-12-01

    A large-volume cubic high-pressure apparatus with three pairs of tungsten carbide anvils is the most popular device for synthetic diamond production. Currently, the consumption of anvils is one of the important costs for the diamond production industry. If one of the anvils is fractured during the production process, the other five anvils in the apparatus may be endangered as a result of a sudden loss of pressure. It is of critical importance to detect and replace cracked anvils before they fracture for reduction of the cost of diamond production and safety. An acoustic detection method is studied in this paper. Two new features, nested power spectrum centroid and modified power spectrum variance, are proposed and combined with linear prediction coefficients to construct a feature vector. A support vector machine model is trained for classification. A sliding time window is proposed for decision-level information fusion. The experiments and analysis show that the recognition rate of anvil cracks is 95%, while the false-alarm rate is as low as 5.8 × 10(-4) during a time window; this false-alarm rate indicates that at most one false alarm occurs every 2 months at a confidence level of 90%. An instrument to monitor anvil cracking was designed based on a digital signal processor and has been running for more than eight months in a diamond production field. In this time, two anvil-crack incidents occurred and were detected by the instrument correctly. In addition, no false alarms occurred.

  19. Monitoring microstructural evolution of alloy 617 with non-linear acoustics for remaining useful life prediction; multiaxial creep-fatigue and creep-ratcheting

    SciTech Connect

    Lissenden, Cliff; Hassan, Tasnin; Rangari, Vijaya

    2014-10-30

    The research built upon a prior investigation to develop a unified constitutive model for design-­by-­analysis of the intermediate heat exchanger (IHX) for a very high temperature reactor (VHTR) design of next generation nuclear plants (NGNPs). Model development requires a set of failure data from complex mechanical experiments to characterize the material behavior. Therefore uniaxial and multiaxial creep-­fatigue and creep-­ratcheting tests were conducted on the nickel-­base Alloy 617 at 850 and 950°C. The time dependence of material behavior, and the interaction of time dependent behavior (e.g., creep) with ratcheting, which is an increase in the cyclic mean strain under load-­controlled cycling, are major concerns for NGNP design. This research project aimed at characterizing the microstructure evolution mechanisms activated in Alloy 617 by mechanical loading and dwell times at elevated temperature. The acoustic harmonic generation method was researched for microstructural characterization. It is a nonlinear acoustics method with excellent potential for nondestructive evaluation, and even online continuous monitoring once high temperature sensors become available. It is unique because it has the ability to quantitatively characterize microstructural features well before macroscale defects (e.g., cracks) form. The nonlinear acoustics beta parameter was shown to correlate with microstructural evolution using a systematic approach to handle the complexity of multiaxial creep-­fatigue and creep-­ratcheting deformation. Mechanical testing was conducted to provide a full spectrum of data for: thermal aging, tensile creep, uniaxial fatigue, uniaxial creep-­fatigue, uniaxial creep-ratcheting, multiaxial creep-fatigue, and multiaxial creep-­ratcheting. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Optical Microscopy were conducted to correlate the beta parameter with individual microstructure mechanisms. We researched

  20. Methods and apparatus for measurement of the resistivity of geological formations from within cased wells in presence of acoustic and magnetic energy sources

    DOEpatents

    Vail, W.B. III.

    1991-08-27

    Methods and apparatus are provided for measuring the acoustically modulated electronic properties of geological formations and cement layers adjacent to cased boreholes. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. Voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the leakage current conducted into formation in the vicinity of those electrodes. Simultaneously subjecting the casing and formation to an acoustic source acoustically modulates the leakage current measured thereby providing a measure of the acoustically modulated electronic properties of the adjacent formation. Similarly, methods and apparatus are also described which measure the leakage current into formation while simultaneously subjecting the casing to an applied magnetic field which therefore allows measurement of the magnetically modulated electronic properties of the casing and the adjacent formation. 9 figures.

  1. Methods and apparatus for measurement of the resistivity of geological formations from within cased wells in presence of acoustic and magnetic energy sources

    DOEpatents

    Vail, III, William B.

    1991-01-01

    Methods and apparatus are provided for measuring the acoustically modulated electronic properties of geological formations and cement layers adjacent to cased boreholes. Current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. Voltage measuring electrodes in electrical contact with the interior of the casing measure the voltage at various points thereon. The voltage differences between discrete pairs of the voltage measuring electrodes provide a measurement of the leakage current conducted into formation in the vicinity of those electrodes. Simultaneously subjecting the casing and formation to an acoustic source acoustically modulates the leakage current measured thereby providing a measure of the acoustically modulated electronic properties of the adjacent formation. Similarly, methods and apparatus are also described which measure the leakage current into formation while simultaneously subjecting the casing to an applied magnetic field which therefore allows measurement of the magnetically modulated electronic properties of the casing and the adjacent formation.

  2. High intensity acoustic tests of a thermally stressed aluminum plate in TAFA

    NASA Technical Reports Server (NTRS)

    Ng, Chung Fai; Clevenson, Sherman A.

    1989-01-01

    An investigation was conducted in the Thermal Acoustic Fatigue Apparatus at the Langley Research Center to study the acoustically excited random motion of an aluminum plate which is buckled due to thermal stresses. The thermal buckling displacements were measured and compared with theory. The general trends of the changes in resonances frequencies and random responses of the plate agree with previous theoretical prediction and experimental results for a mechanically buckled plate.

  3. Apparatus and method for fatigue testing of a material specimen in a high-pressure fluid environment

    DOEpatents

    Wang, Jy-An; Feng, Zhili; Anovitz, Lawrence M; Liu, Kenneth C

    2013-06-04

    The invention provides fatigue testing of a material specimen while the specimen is disposed in a high pressure fluid environment. A specimen is placed between receivers in an end cap of a vessel and a piston that is moveable within the vessel. Pressurized fluid is provided to compression and tension chambers defined between the piston and the vessel. When the pressure in the compression chamber is greater than the pressure in the tension chamber, the specimen is subjected to a compression force. When the pressure in the tension chamber is greater than the pressure in the compression chamber, the specimen is subjected to a tension force. While the specimen is subjected to either force, it is also surrounded by the pressurized fluid in the tension chamber. In some examples, the specimen is surrounded by hydrogen.

  4. Acoustical standards in engineering acoustics

    NASA Astrophysics Data System (ADS)

    Burkhard, Mahlon D.

    2001-05-01

    The Engineering Acoustics Technical Committee is concerned with the evolution and improvement of acoustical techniques and apparatus, and with the promotion of new applications of acoustics. As cited in the Membership Directory and Handbook (2002), the interest areas include transducers and arrays; underwater acoustic systems; acoustical instrumentation and monitoring; applied sonics, promotion of useful effects, information gathering and transmission; audio engineering; acoustic holography and acoustic imaging; acoustic signal processing (equipment and techniques); and ultrasound and infrasound. Evident connections between engineering and standards are needs for calibration, consistent terminology, uniform presentation of data, reference levels, or design targets for product development. Thus for the acoustical engineer standards are both a tool for practices, for communication, and for comparison of his efforts with those of others. Development of many standards depends on knowledge of the way products are put together for the market place and acoustical engineers provide important input to the development of standards. Acoustical engineers and members of the Engineering Acoustics arm of the Society both benefit from and contribute to the Acoustical Standards of the Acoustical Society.

  5. Method and apparatus for acoustically monitoring the flow of suspended solid particulate matter. [Patent application; monitoring char flow in coal gasifier

    DOEpatents

    Roach, P.D.; Raptis, A.C.

    1980-11-24

    A method and apparatus for monitoring char flow in a coal gasifier system includes flow monitor circuits which measure acoustic attenuation caused by the presence of char in a char line and provides a char flow/no flow indication and an indication of relative char density. The flow monitor circuits compute the ratio of signals in two frequency bands, a first frequency band representative of background noise, and a second higher frequency band in which background noise is attenuated by the presence of char. Since the second frequency band contains higher frequencies, the ratio can be used to provide a flow/no flow indication. The second band can also be selected so that attenuation is monotonically related to particle concentration, providing a quantitative measure of char concentration.

  6. GRAAL - Griggs-type Apparatus equipped with Acoustics in the Laboratory: a new instrument to explore the rheology of rocks at high pressure

    NASA Astrophysics Data System (ADS)

    Schubnel, A.; Champallier, R.; Precigout, J.; Pinquier, Y.; Ferrand, T. P.; Incel, S.; Hilairet, N.; Labrousse, L.; Renner, J.; Green, H. W., II; Stunitz, H.; Jolivet, L.

    2015-12-01

    Two new generation solid-medium Griggs-type apparatus have been set up at the Laboratoire de Géologie of ENS PARIS, and the Institut des Sciences de la Terre d'Orléans (ISTO). These new set-ups allow to perform controlled rock deformation experiments on large volume samples, up to 5 GPa and 1300°C. Careful pressure - stress calibration will be performed (using D-DIA and/or Paterson-type experiments as standards), strain-stress-pressure will be measured using modern techniques and state of the art salt assemblies. Focusing on rheology, the pressure vessel at ISTO has been designed in a goal of deforming large sample diameter (8 mm) at confining pressure of up to 3 GPa. Thanks to this large sample size, this new vessel will allow to explore the microstructures related to the deformation processes occurring at pressures of the deep lithosphere and in subduction zones. In this new apparatus, we moreover included a room below the pressure vessel in order to develop a basal load cell as close as possible to the sample. This new design, in progress, aims at significantly improving the accuracy of stress measurements in the Griggs-type apparatus. The ultimate goal is to set up a new technique able to routinely quantify the rheology of natural rocks between 0.5 and 5 GPa. Although fundamental to document the rheology of the lithosphere, such a technique is still missing in rock mechanics. Focusing on the evolution of physical and mechanical properties during mineral phase transformations, the vessel at ENS is equipped with continuous acoustic emission (AE) multi-sensor monitoring in order to "listen" to the sample during deformation. Indeed, these continuous recordings enable to detect regular AE like signals during dynamic crack propagation, as well as non-impulsive signals, which might be instrumental to identify laboratory analogs to non-volcanic tremor and low frequency earthquake signals. P and S elastic wave velocities will also be measured contemporaneously during

  7. Acoustophoresis method and apparatus

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S. (Inventor)

    1992-01-01

    A method and apparatus are provided for acoustophoresis, i.e., the separation of species via acoustic waves. An ultrasonic transducer applies an acoustic wave to one end of a sample container containing at least two species having different acoustic absorptions. The wave has a frequency tuned to or harmonized with the point of resonance of the species to be separated. This wave caused the species to be driven to an opposite end of the sample container for removal. A second ultrasonic transducer may be provided to apply a second, oppositely directed acoustic wave to prevent undesired streaming. In addition, a radio frequency tuned to the mechanical resonance and coupled with a magnetic field can serve to identify a species in a medium comprising species with similar absorption coefficients, whereby an acoustic wave having a frequency corresponding to this gyrational rate can then be applied to sweep the identified species to one end of the container for removal.

  8. [A new pocket-type flicker apparatus].

    PubMed

    Hosokawa, T; Makizuka, T; Nakai, K; Saito, K

    1989-09-01

    A small, light and inexpensive pocket flicker (P.F.) apparatus for measuring fatigue was designed, fabricated and tested. The apparatus, being composed of a light emitting diode and a variable resistor with a scale, is so compact that it can be carried in a shirt pocket. Thus, critical fusion frequency (CFF) values can be easily determined at a working place and the load involved is small when compared to other physical fatigue measurements and earlier CFF apparatuses. Moreover, the apparatus is so inexpensive that it can be widely used. To compare the performance of the P.F. apparatus with earlier apparatuses, the following experiments were performed. CFF values were measured at the same time with the pocket type apparatus, blinking type apparatus and sector type apparatus and the results were compared. The subjects were 13 males and 5 females with their age ranging from 21 to 52 years. The total number of measurements was 132. The CFF values measured with these three apparatuses showed a significant correlation. The correlation coefficient between the CFF values measured with the sector type apparatus and blinking type apparatus was high, but the slope of the regression line was not one. Hence, in comparing the values measured with another apparatus, we should be aware of the differences between these data. The correlation coefficients between the CFF values measured with P.F. apparatus and with sector type apparatus or blinking type apparatus were not higher than those between the CFF values measured with sector type apparatus and blinking type apparatus.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2585810

  9. Acoustic Translation of an Acoustically Levitated Sample

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Allen, J. L.

    1986-01-01

    Acoustic-levitation apparatus uses only one acoustic mode to move sample from one region of chamber to another. Sample heated and cooled quickly by translation between hot and cold regions of levitation chamber. Levitated sample is raised into furnace region by raising plunger. Frequency of sound produced by transducers adjusted by feedback system to maintain (102) resonant mode, which levitates sample midway between transducers and plunger regardless of plunger position.

  10. High Speed Research Program Sonic Fatigue

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A. (Technical Monitor); Beier, Theodor H.; Heaton, Paul

    2005-01-01

    The objective of this sonic fatigue summary is to provide major findings and technical results of studies, initiated in 1994, to assess sonic fatigue behavior of structure that is being considered for the High Speed Civil Transport (HSCT). High Speed Research (HSR) program objectives in the area of sonic fatigue were to predict inlet, exhaust and boundary layer acoustic loads; measure high cycle fatigue data for materials developed during the HSR program; develop advanced sonic fatigue calculation methods to reduce required conservatism in airframe designs; develop damping techniques for sonic fatigue reduction where weight effective; develop wing and fuselage sonic fatigue design requirements; and perform sonic fatigue analyses on HSCT structural concepts to provide guidance to design teams. All goals were partially achieved, but none were completed due to the premature conclusion of the HSR program. A summary of major program findings and recommendations for continued effort are included in the report.

  11. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination.

    PubMed

    Bodini, I; Sansoni, G; Lancini, M; Pasinetti, S; Docchio, F

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens. PMID:27587125

  12. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination.

    PubMed

    Bodini, I; Sansoni, G; Lancini, M; Pasinetti, S; Docchio, F

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens.

  13. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination

    NASA Astrophysics Data System (ADS)

    Bodini, I.; Sansoni, G.; Lancini, M.; Pasinetti, S.; Docchio, F.

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens.

  14. Sonic levitation apparatus

    NASA Technical Reports Server (NTRS)

    Dunn, S. A.; Pomplum, A. R.; Paquette, E. G.; Ethridge, E. C.; Johnson, J. L. (Inventor)

    1984-01-01

    A sonic levitation apparatus is disclosed which includes a sonic transducer which generates acoustical energy responsive to the level of an electrical amplifier. A duct communicates with an acoustical chamber to deliver an oscillatory motion of air to a plenum section which contains a collimated hole structure having a plurality of parallel orifices. The collimated hole structure converts the motion of the air to a pulsed. Unidirectional stream providing enough force to levitate a material specimen. Particular application to the production of microballoons in low gravity environment is discussed.

  15. Ultrasonic inspection and deployment apparatus

    DOEpatents

    Michaels, Jennifer E.; Michaels, Thomas E.; Mech, Jr., Stephen J.

    1984-01-01

    An ultrasonic inspection apparatus for the inspection of metal structures, especially installed pipes. The apparatus combines a specimen inspection element, an acoustical velocity sensing element, and a surface profiling element, all in one scanning head. A scanning head bellows contains a volume of oil above the pipe surface, serving as acoustical couplant between the scanning head and the pipe. The scanning head is mounted on a scanning truck which is mobile around a circular track surrounding the pipe. The scanning truck has sufficient motors, gears, and position encoders to allow the scanning head six degrees of motion freedom. A computer system continually monitors acoustical velocity, and uses that parameter to process surface profiling and inspection data. The profiling data is used to automatically control scanning head position and alignment and to define a coordinate system used to identify and interpret inspection data. The apparatus is suitable for highly automated, remote application in hostile environments, particularly high temperature and radiation areas.

  16. TV fatigue crack monitoring system

    NASA Technical Reports Server (NTRS)

    Exton, R. J. (Inventor)

    1977-01-01

    An apparatus is disclosed for monitoring the development and growth of fatigue cracks in a test specimen subjected to a pulsating tensile load. A plurality of television cameras photograph a test specimen which is illuminated at the point of maximum tensile stress. The television cameras have a modified vidicon tube which has an increased persistence time thereby eliminating flicker in the displayed images.

  17. Apparatus for ultrasonic nebulization

    DOEpatents

    Olson, Kenneth W.; Haas, Jr., William J.; Fassel, Velmer A.

    1978-08-29

    An improved apparatus for ultrasonic nebulization of liquid samples or suspensions in which the piezoelectric transducer is protected from chemical attack and erosion. The transducer is protected by being bonded to the inner surface of a glass plate which forms one end wall of a first hollow body provided with apparatus for circulating a fluid for cooling and stabilizing the transducer. The glass plate, which is one-half wavelength in thickness to provide an acoustically coupled outer nebulizing surface, seals an opening in a second hollow body which encloses an aerosol mixing chamber. The second body includes apparatus for delivering the sample solution to the nebulizing surface, a gas inlet for providing a flow of carrier gas for transporting the aerosol of the nebulized sample and an aerosol outlet.

  18. Apparatus Notes.

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1978-01-01

    Describes three pieces of scientific apparatus and their demonstrational use: a high temperature apparatus for positron annihilation studies, a digitally synthesized classroom variable star, and a demonstration of plasma laser-beam focusing using paint stripper flames. (GA)

  19. Apparatus for particulate matter analysis

    DOEpatents

    Gundel, Lara A.; Apte, Michael G.; Hansen, Anthony D.; Black, Douglas R.

    2007-01-30

    The apparatus described herein is a miniaturized system for particle exposure assessment (MSPEA) for the quantitative measurement and qualitative identification of particulate content in gases. The present invention utilizes a quartz crystal microbalance (QCM) or other mass-sensitive temperature compensated acoustic wave resonator for mass measurement. Detectors and probes and light sources are used in combination for the qualitative determination of particulate matter.

  20. Reversal bending fatigue testing

    SciTech Connect

    Wang, Jy-An John; Wang, Hong; Tan, Ting

    2014-10-21

    Embodiments for apparatuses for testing reversal bending fatigue in an elongated beam are disclosed. Embodiments are configured to be coupled to first and second end portions of the beam and to apply a bending moment to the beam and create a pure bending condition in an intermediate portion of the beam. Embodiments are further configured to cyclically alternate the direction of the bending moment applied to the beam such that the intermediate portion of the beam cyclically bends in opposite directions in a pure bending condition.

  1. Precision cleaning apparatus and method

    DOEpatents

    Schneider, T.W.; Frye, G.C.; Martin, S.J.

    1998-01-13

    A precision cleaning apparatus and method are disclosed. The precision cleaning apparatus includes a cleaning monitor further comprising an acoustic wave cleaning sensor such as a quartz crystal microbalance (QCM), a flexural plate wave (FPW) sensor, a shear horizontal acoustic plate mode (SH--APM) sensor, or a shear horizontal surface acoustic wave (SH--SAW) sensor; and measurement means connectable to the sensor for measuring in-situ one or more electrical response characteristics that vary in response to removal of one or more contaminants from the sensor and a workpiece located adjacent to the sensor during cleaning. Methods are disclosed for precision cleaning of one or more contaminants from a surface of the workpiece by means of the cleaning monitor that determines a state of cleanliness and any residual contamination that may be present after cleaning; and also for determining an effectiveness of a cleaning medium for removing one or more contaminants from a workpiece. 11 figs.

  2. Precision cleaning apparatus and method

    DOEpatents

    Schneider, Thomas W.; Frye, Gregory C.; Martin, Stephen J.

    1998-01-01

    A precision cleaning apparatus and method. The precision cleaning apparatus includes a cleaning monitor further comprising an acoustic wave cleaning sensor such as a quartz crystal microbalance (QCM), a flexural plate wave (FPW) sensor, a shear horizontal acoustic plate mode (SH--APM) sensor, or a shear horizontal surface acoustic wave (SH--SAW) sensor; and measurement means connectable to the sensor for measuring in-situ one or more electrical response characteristics that vary in response to removal of one or more contaminants from the sensor and a workpiece located adjacent to the sensor during cleaning. Methods are disclosed for precision cleaning of one or more contaminants from a surface of the workpiece by means of the cleaning monitor that determines a state of cleanliness and any residual contamination that may be present after cleaning; and also for determining an effectiveness of a cleaning medium for removing one or more contaminants from a workpiece.

  3. Acoustic well cleaner

    DOEpatents

    Maki, Jr., Voldi E.; Sharma, Mukul M.

    1997-01-21

    A method and apparatus are disclosed for cleaning the wellbore and the near wellbore region. A sonde is provided which is adapted to be lowered into a borehole and which includes a plurality of acoustic transducers arranged around the sonde. Electrical power provided by a cable is converted to acoustic energy. The high intensity acoustic energy directed to the borehole wall and into the near wellbore region, redissolves or resuspends the material which is reducing the permeability of the formation and/or restricting flow in the wellbore.

  4. Combined high vacuum/high frequency fatigue tester

    NASA Technical Reports Server (NTRS)

    Honeycutt, C. R.; Martin, T. F.

    1971-01-01

    Apparatus permits application of significantly greater number of cycles or equivalent number of cycles in shorter time than conventional fatigue test machines. Environment eliminates problems associated with high temperature oxidation and with sensitivity of refractory alloy behavior to atmospheric contamination.

  5. Acoustic ground impedance meter

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J. (Inventor)

    1984-01-01

    A method and apparatus are presented for measuring the acoustic impedance of a surface in which the surface is used to enclose one end of the chamber of a Helmholz resonator. Acoustic waves are generated in the neck of the resonator by a piston driven by a variable speed motor through a cam assembly. The acoustic waves are measured in the chamber and the frequency of the generated acoustic waves is measured by an optical device. These measurements are used to compute the compliance and conductance of the chamber and surface combined. The same procedure is followed with a calibration plate having infinite acoustic impedance enclosing the chamber of the resonator to compute the compliance and conductance of the chamber alone. Then by subtracting, the compliance and conductance for the surface is obtained.

  6. Acoustic emission monitoring system

    DOEpatents

    Romrell, Delwin M.

    1977-07-05

    Methods and apparatus for identifying the source location of acoustic emissions generated within an acoustically conductive medium. A plurality of acoustic receivers are communicably coupled to the surface of the medium at a corresponding number of spaced locations. The differences in the reception time of the respective sensors in response to a given acoustic event are measured among various sensor combinations prescribed by the monitoring mode employed. Acoustic reception response encountered subsequent to the reception by a predetermined number of the prescribed sensor combinations are inhibited from being communicated to the processing circuitry, while the time measurements obtained from the prescribed sensor combinations are translated into a position measurement representative of the location on the surface most proximate the source of the emission. The apparatus is programmable to function in six separate and five distinct operating modes employing either two, three or four sensory locations. In its preferred arrangement the apparatus of this invention will re-initiate a monitoring interval if the predetermined number of sensors do not respond to a particular emission within a given time period.

  7. Detection Apparatus

    DOEpatents

    Anderson, H L

    1950-12-05

    This invention concerns a sensitive apparatus for detecting and counting neutrons, particularly neutrons liberated in an alpha, neutron reaction. The apparatus includes an improved ionization chamber structure together with an improved combination alpha-particle source and holder for the material under test.

  8. Particle analysis in an acoustic cytometer

    DOEpatents

    Kaduchak, Gregory; Ward, Michael D

    2012-09-18

    The present invention is a method and apparatus for acoustically manipulating one or more particles. Acoustically manipulated particles may be separated by size. The particles may be flowed in a flow stream and acoustic radiation pressure, which may be radial, may be applied to the flow stream. This application of acoustic radiation pressure may separate the particles. In one embodiment, the particles may be separated by size, and as a further example, the larger particles may be transported to a central axis.

  9. Field Measurement of the Acoustic Nonlinearity Parameter in Turbine Blades

    NASA Technical Reports Server (NTRS)

    Hinton, Yolanda L.; Na, Jeong K.; Yost, William T.; Kessel, Gregory L.

    2000-01-01

    Nonlinear acoustics techniques were used to measure fatigue in turbine blades in a power generation plant. The measurements were made in the field using a reference based measurement technique, and a reference sample previously measured in the laboratory. The acoustic nonlinearity parameter showed significant increase with fatigue in the blades, as indicated by service age and areas of increased stress. The technique shows promise for effectively measuring fatigue in field applications and predicting subsequent failures.

  10. Apparatus Notes.

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1982-01-01

    Presents a technique to produce samples for x-ray diffraction studies on the Tel-X-Ometer 80 x-ray apparatus from readily available crystalline powders and discusses observations of transverse modes of an optical resonator. (SK)

  11. Apparatus Notes

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1976-01-01

    Includes five brief articles on: solar-heating demonstration equipment, mercury or sodium vapor lamp spectroscopy, an apparatus for simulating variable stars, a voltage-to-frequency converter, and an introductory absorption experiment for low-energy beta particles. (MLH)

  12. Packard's Apparatus.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1996-01-01

    Describes the Packard's Falling Body Apparatus, invented by John C. Packard, which is essentially an inclined plane combined with a simple and elegant method of measuring the relative time of descent of a steel ball. (JRH)

  13. Sonic fatigue of launch vehicle components

    SciTech Connect

    Wentz, K.R.; Camden, M.P.

    1997-01-01

    Wright Laboratory has long been a leader in the technologies required for aerospace structures. One of these driving technology areas is that of the dynamic environments of acoustics and vibration to which structures are exposed and required to survive. This paper presents an overview of sonic fatigue of launch vehicle components. An experimental program to develop sonic fatigue design criteria for a proposed thermal protection system is reviewed. Wright Laboratory{close_quote}s experimental facilities utilized to subject structures to simulated launch vehicle environments which are necessary to generate the experimental data required to provide sonic fatigue design criteria are described. {copyright} {ital 1997 American Institute of Physics.}

  14. Resolution enhanced sound detecting apparatus

    NASA Technical Reports Server (NTRS)

    Kendall, J. M. (Inventor)

    1979-01-01

    An apparatus is described for enhancing the resolution of a sound detector of the type which includes an acoustic mirror for focusing sound from an object onto a microphone to enable the determination of the location from which the sound arises. The enhancement apparatus includes an enclosure which surrounds the space between the mirror and microphone, and contains a gas heavier than air, such as Freon, through which sound moves slower and therefore with a shorter wavelength than in air, so that a mirror of given size has greater resolving power. An acoustically transparent front wall of the enclosure which lies forward of the mirror, can include a pair of thin sheets with pressured air between them, to form an end of the region of heavy gas into a concave shape.

  15. Chronic Fatigue Syndrome

    MedlinePlus

    Chronic fatigue syndrome (CFS) is a disorder that causes extreme fatigue. This fatigue is not the kind of tired feeling that ... activities. The main symptom of CFS is severe fatigue that lasts for 6 months or more. You ...

  16. Structures and Acoustics Division

    NASA Technical Reports Server (NTRS)

    Acquaviva, Cynthia S.

    1999-01-01

    The Structures and Acoustics Division of NASA Glenn Research Center is an international leader in rotating structures, mechanical components, fatigue and fracture, and structural aeroacoustics. Included are disciplines related to life prediction and reliability, nondestructive evaluation, and mechanical drive systems. Reported are a synopsis of the work and accomplishments reported by the Division during the 1996 calendar year. A bibliography containing 42 citations is provided.

  17. Structures and Acoustics Division

    NASA Technical Reports Server (NTRS)

    Acquaviva, Cynthia S.

    2001-01-01

    The Structures and Acoustics Division of the NASA Glenn Research Center is an international leader in rotating structures, mechanical components, fatigue and fracture, and structural aeroacoustics. Included in this report are disciplines related to life prediction and reliability, nondestructive evaluation, and mechanical drive systems. Reported is a synopsis of the work and accomplishments completed by the Division during the 1997, 1998, and 1999 calendar years. A bibliography containing 93 citations is provided.

  18. Method and apparatus for measuring stress

    DOEpatents

    Thompson, R.B.

    1983-07-28

    A method and apparatus for determining stress in a material independent of micro-structural variations and anisotropies. The method comprises comparing the velocities of two horizontally polarized and horizontally propagating ultrasonic shear waves with interchanged directions of propagation and polarization. The apparatus for carrying out the method comprises periodic permanent magnet-electromagnetic acoustic transducers for generating and detecting the shear waves and means for determining the wave velocities.

  19. Method and apparatus for measuring stress

    DOEpatents

    Thompson, R. Bruce

    1985-06-11

    A method and apparatus for determining stress in a material independent of micro-structural variations and anisotropies. The method comprises comparing the velocities of two horizontally polarized and horizontally propagating ultrasonic shear waves with interchanged directions of propagation and polarization. The apparatus for carrying out the method comprises periodic permanent magnet-electromagnetic acoustic transducers for generating and detecting the shear waves and means for determining the wave velocities.

  20. Fatigue Fractures

    PubMed Central

    Morris, James M.

    1968-01-01

    Fatigue (or stress) fracture of bone in military recruits has been recognized for many years. Most often it is a metatarsal bone that is involved but the tarsal bones, calcaneus, tibia, fibula, femur, and pelvis are occasionally affected. Reports of such fractures in the ribs, ulna and vertebral bodies may be found in the literature. In recent years, there has been increasing awareness of the occurrence of fatigue fractures in the civilian population. Weekend sportsmen, athletes in an early phase of training, and persons engaged in unaccustomed, repetitive, vigorous activity are potential victims of such a fracture. The signs and symptoms, roentgenographic findings, treatment and etiology of fatigue fractures are dealt with in this presentation. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6. PMID:5652745

  1. Apparatus at right, center is prototype for automatic record changing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Apparatus at right, center is prototype for automatic record changing device for acoustical phonographs - Thomas A. Edison Laboratories, Building No. 5, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

  2. Control apparatus

    NASA Technical Reports Server (NTRS)

    Derkacs, Thomas (Inventor); Fetheroff, Charles W. (Inventor); Matay, Istvan M. (Inventor); Toth, Istvan J. (Inventor)

    1982-01-01

    Although the method and apparatus of the present invention can be utilized to apply either a uniform or a nonuniform covering of material over many different workpieces, the apparatus (20) is advantageously utilized to apply a thermal barrier covering (64) to an airfoil (22) which is used in a turbine engine. The airfoil is held by a gripper assembly (86) while a spray gun (24) is effective to apply the covering over the airfoil. When a portion of the covering has been applied, a sensor (28) is utilized to detect the thickness of the covering. A control apparatus (32) compares the thickness of the covering of material which has been applied with the desired thickness and is subsequently effective to regulate the operation of the spray gun to adaptively apply a covering of a desired thickness with an accuracy of at least plus or minus 0.0015 inches (1.5 mils) despite unanticipated process variations.

  3. MOLDING APPARATUS

    DOEpatents

    Fleming, P.G.

    1963-10-01

    Molding apparatus capable of coating multiple elements each molding cycle is described. The apparatus comprises a centrally disposed reservoir penetrated by a plurality of circumferentially arranged and radially extending passageways. These passageways, in turn, communicate with passages in a separable annular member that retains selectively configured molds and mold seating arrangements. Each mold, which is readily removable from its respective seat, is adapted to retain an element therein in spaced relation to the interior of the mold by utilizing element positioning means within the mold seat and the mold so that coating material may flow about the entire outer surface of the element. (AEC)

  4. Positioning apparatus

    DOEpatents

    Vogel, M.A.; Alter, P.

    1983-07-07

    An apparatus is provided for precisely adjusting the position of an article relative to a beam emerging from a neutron source disposed in a housing. The apparatus includes a support pivotably mounted on a movable base plate and freely suspended therefrom. The support is gravity biased toward the housing and carries an article holder movable in a first direction longitudinally of the axis of said beam and normally urged into engagement against said housing. Means are provided for moving the base plate in two directions to effect movement of the suspended holder in two mutually perpendicular directions, respectively, normal to the axis of the beam.

  5. Irradiation apparatus

    DOEpatents

    Goldie, C.H.; Fernald, R.A.

    1974-01-29

    An apparatus for introducing ionizing radiation into compressed gas insulation systems, such as high-voltage generators or transmission lines to smooth out electrical discontinuities, particularly those caused by foreign particulates that produce high gradients, and to increase the voltage holding capability of the system is described. The apparatus of the invention may also be used to regulate and stabilize the voltage of the system by varying the amount of applied load. A corona discharge device may also be used in conjunction with the invention. (Official Gazette)

  6. TRANSFORMER APPARATUS

    DOEpatents

    Wolfgang, F.; Nicol, J.

    1962-11-01

    Transformer apparatus is designed for measuring the amount of a paramagnetic substance dissolved or suspended in a diamagnetic liquid. The apparatus consists of a cluster of tubes, some of which are closed and have sealed within the diamagnetic substance without any of the paramagnetic material. The remaining tubes are open to flow of the mix- ture. Primary and secondary conductors are wrapped around the tubes in such a way as to cancel noise components and also to produce a differential signal on the secondaries based upon variations of the content of the paramagnetic material. (AEC)

  7. Method and apparatus for controlling gas evolution from chemical reactions

    DOEpatents

    Skorpik, James R.; Dodson, Michael G.

    1999-01-01

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846.

  8. Method and apparatus for controlling gas evolution from chemical reactions

    DOEpatents

    Skorpik, J.R.; Dodson, M.G.

    1999-05-25

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846. 8 figs.

  9. High speed thin plate fatigue crack monitor

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz A. (Inventor); Heyman, Joseph S. (Inventor); Namkung, Min (Inventor); Fulton, James P. (Inventor)

    1996-01-01

    A device and method are provided which non-destructively detect crack length and crack geometry in thin metallic plates. A non-contacting vibration apparatus produces resonant vibrations without introducing extraneous noise. Resulting resonant vibration shifts in cracked plates are correlated to known crack length in plates with similar resonant vibration shifts. In addition, acoustic emissions of cracks at resonance frequencies are correlated to acoustic emissions from known crack geometries.

  10. Reliability improvement of wire bonds subjected to fatigue stresses.

    NASA Technical Reports Server (NTRS)

    Ravi, K. V.; Philofsky, E. M.

    1972-01-01

    The failure of wire bonds due to repeated flexure when semiconductor devices are operated in an on-off mode has been investigated. An accelerated fatigue testing apparatus was constructed and the major fatigue variables, aluminum alloy composition, and bonding mechanism, were tested. The data showed Al-1% Mg wires to exhibit superior fatigue characteristics compared to Al-1% Cu or Al-1% Si and ultrasonic bonding to be better than thermocompression bonding for fatigue resistance. Based on these results highly reliable devices were fabricated using Al-1% Mg wire with ultrasonic bonding which withstood 120,000 power cycles with no failures.

  11. Apparatus Notes.

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1981-01-01

    Describes experiments and apparatus to: (1) allow astronomy students to test resolution limit of their eyes at several wavelengths; (2) analyze laser mode phases by interferometry; (3) demonstrate a Cartesian diver with an overhead projector; and (4) generate conical beams of light for smoke-chamber demonstrations. (JN)

  12. Prehensile apparatus

    DOEpatents

    Smith, Christopher M.

    1993-01-01

    The present invention relates to an apparatus for handling a workpiece comprising a vessel that is longitudinally extensible and pressurizable, and a nonextensible and laterally flexible member on the vessel. The member constrains one side of the vessel to be nonextensible, causing the vessel to bend in the direction of the nonextensible member when pressurized.

  13. Prehensile apparatus

    DOEpatents

    Smith, C.M.

    1993-10-12

    The present invention relates to an apparatus for handling a workpiece comprising a vessel that is longitudinally extensible and pressurizable, and a nonextensible and laterally flexible member on the vessel. The member constrains one side of the vessel to be nonextensible, causing the vessel to bend in the direction of the nonextensible member when pressurized. 8 figures.

  14. Apparatus Reviews.

    ERIC Educational Resources Information Center

    School Science Review, 1978

    1978-01-01

    Describes some science apparatus: included are a gene kit to demonstrate aspects of population genetics and selection, an electronic thermometer for use in the field of environmental studies, an astrobrella to use in astronomy classes, and crystal display models of different substances for chemistry classes. (GA)

  15. Apparatus Reviews.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Provided are reviews of science equipment/apparatus. Items reviewed include: Harris Micro-ecology tubes; Harris chromosome investigation kit; Harris trycult slides; a pressure cooker with thermometer; digital pH meter; digital scaler timer; electrical compensation calorimeter; and Mains alternating current ammeter. (JN)

  16. Apparatus Notes

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1977-01-01

    Presents four short articles on: a power supply for the measurement of the charge-to-mass ratio of the electron; a modified centripetal force apparatus; a black box electronic unknown for the scientific instruments laboratory; and a simple scaling model for biological systems. (MLH)

  17. Apparatus Notes.

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1980-01-01

    This collection of notes describes (1) an optoelectronic apparatus for classroom demonstrations of mechanical laws, (2) a more efficient method for demonstrated nuclear chain reactions using electrically energized "traps" and ping-pong balls, and (3) an inexpensive demonstration for qualitative analysis of temperature-dependent resistance. (CS)

  18. Apparatus Reviews.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Reviews apparatus design and instructional uses for Fume Cupboard Monitor, Plant Tissue Culture Kit, various equipment for electronic systems course, Welwyn Microprocessor-Tutor, Sweep Function Generator SFG 606, and Harris manufacturers materials--Regulated Power Supply Units, Electronic Current and Voltage Meters, Gas Preparation Kit, and…

  19. Exercise apparatus

    NASA Technical Reports Server (NTRS)

    Schaffner, Grant (Inventor); Bentley, Jason R. (Inventor); Loehr, James A. (Inventor); Gundo, Daniel P. (Inventor)

    2006-01-01

    An apparatus and method for exercising whereby the user is supported by various mechanisms in such as way that the user's shoulder area is free to translate and rotate; the user's pelvic area is free to translate and rotate; or in any combination.

  20. Apparatus Notes.

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1979-01-01

    Presents brief notes on new ideas, equipment, techniques, or materials of interest to teachers of physics. An apparatus that demonstrates the uniform acceleration of gravity, and a simple way to demonstrate nuclear blocking patterns of crystal lattices are among new ideas presented. (HM)

  1. The Simplest Demonstration on Acoustic Beats

    ERIC Educational Resources Information Center

    Ganci, Alessio; Ganci, Salvatore

    2015-01-01

    The classical demonstration experiment on acoustic beats using two signal generators and a dual trace oscilloscope is an important ingredient in teaching the subject. This short laboratory note aims to point out what may be the simplest demonstrative experiment on acoustic beats to carry out in a classroom without employing any lab apparatus.

  2. Mean stress and the exhaustion of fatigue-damage resistance

    NASA Technical Reports Server (NTRS)

    Berkovits, Avraham

    1989-01-01

    Mean-stress effects on fatigue life are critical in isothermal and thermomechanically loaded materials and composites. Unfortunately, existing mean-stress life-prediction methods do not incorporate physical fatigue damage mechanisms. An objective is to examine the relation between mean-stress induced damage (as measured by acoustic emission) and existing life-prediction methods. Acoustic emission instrumentation has indicated that, as with static yielding, fatigue damage results from dislocation buildup and motion until dislocation saturation is reached, after which void formation and coalescence predominate. Correlation of damage processes with similar mechanisms under monotonic loading led to a reinterpretation of Goodman diagrams for 40 alloys and a modification of Morrow's formulation for life prediction under mean stresses. Further testing, using acoustic emission to monitor dislocation dynamics, can generate data for developing a more general model for fatigue under mean stress.

  3. Acoustic resonance frequency locked photoacoustic spectrometer

    DOEpatents

    Pilgrim, Jeffrey S.; Bomse, David S.; Silver, Joel A.

    2003-09-09

    A photoacoustic spectroscopy method and apparatus for maintaining an acoustic source frequency on a sample cell resonance frequency comprising: providing an acoustic source to the sample cell, the acoustic source having a source frequency; repeatedly and continuously sweeping the source frequency across the resonance frequency at a sweep rate; and employing an odd-harmonic of the source frequency sweep rate to maintain the source frequency sweep centered on the resonance frequency.

  4. Acoustic resonance phase locked photoacoustic spectrometer

    DOEpatents

    Pilgrim, Jeffrey S.; Bomse, David S.; Silver, Joel A.

    2003-08-19

    A photoacoustic spectroscopy method and apparatus for maintaining an acoustic source frequency on a sample cell resonance frequency comprising: providing an acoustic source to the sample cell to generate a photoacoustic signal, the acoustic source having a source frequency; continuously measuring detection phase of the photoacoustic signal with respect to source frequency or a harmonic thereof; and employing the measured detection phase to provide magnitude and direction for correcting the source frequency to the resonance frequency.

  5. Prediction of residual fatigue life using nonlinear ultrasound

    NASA Astrophysics Data System (ADS)

    Amura, Mikael; Meo, Michele

    2012-04-01

    Prediction of fatigue life of components during service is an on-going and unsolved challenge for the NDT and structural health monitoring community. It has been demonstrated by a number of researchers that nonlinear guided waves or the acoustic nonlinear signature of fatigued cracked material provides clear signs of the progressive fatigue damage in the material, unlike linear guided waves. However, even with nonlinear acoustic-ultrasound methods there is a necessity to compare the current nonlinear feature to a previously measured cracked material state to assess the absolute residual fatigue life. In this paper, a new procedure based on the measurement of the second-order acoustic nonlinearity is presented which is able to assess the fatigue life of a metallic component without the need of a baseline. The Nazarov-Sutin crack nonlinearity equation and the Paris law are combined in order to obtain an analytical solution able to evaluate the theoretical second-order quadratic nonlinear parameters as a function of the crack growth and fatigue life that evolve during cyclic loading in metals. The model makes the assumption that the crack surface topology has variable geometrical parameters. The method was tested on aluminum alloy specimens AA2024-T351, containing fatigue fracture of different sizes, and excellent correlation was obtained between the theoretical and measured second-order nonlinear parameter. Then, it was demonstrated clearly that by measuring the nonlinear parameters it is possible to estimate crack size and fatigue life. Finally, advantages and limitations of the procedure are discussed.

  6. EXTRACTION APPARATUS

    DOEpatents

    Ballard, A.E.; Brigham, H.R.

    1958-10-28

    An apparatus whereby relatlvely volatile solvents may be contacted with volatile or non-volatile material without certaln attendant hazards is described. A suitable apparatus for handling relatively volatlle liqulds may be constructed comprising a tank, and a closure covering the tank and adapted to be securely attached to an external suppont. The closure is provided with a rigidly mounted motor-driven agitator. This agitator is connected from the driving motor lnto the lnterlor of the tank through a gland adapted to be cooled witb inert gas thereby eliminating possible hazard due to frictional heat. The closure is arranged so that the tank may be removed from it without materially dlsturbing the closure which, as described, carrles the motor driven agitator and other parts.

  7. Sampling apparatus

    DOEpatents

    Gordon, Norman R.; King, Lloyd L.; Jackson, Peter O.; Zulich, Alan W.

    1989-01-01

    A sampling apparatus is provided for sampling substances from solid surfaces. The apparatus includes first and second elongated tubular bodies which telescopically and sealingly join relative to one another. An absorbent pad is mounted to the end of a rod which is slidably received through a passageway in the end of one of the joined bodies. The rod is preferably slidably and rotatably received through the passageway, yet provides a selective fluid tight seal relative thereto. A recess is formed in the rod. When the recess and passageway are positioned to be coincident, fluid is permitted to flow through the passageway and around the rod. The pad is preferably laterally orientable relative to the rod and foldably retractable to within one of the bodies. A solvent is provided for wetting of the pad and solubilizing or suspending the material being sampled from a particular surface.

  8. Sampling apparatus

    DOEpatents

    Gordon, N.R.; King, L.L.; Jackson, P.O.; Zulich, A.W.

    1989-07-18

    A sampling apparatus is provided for sampling substances from solid surfaces. The apparatus includes first and second elongated tubular bodies which telescopically and sealingly join relative to one another. An absorbent pad is mounted to the end of a rod which is slidably received through a passageway in the end of one of the joined bodies. The rod is preferably slidably and rotatably received through the passageway, yet provides a selective fluid tight seal relative thereto. A recess is formed in the rod. When the recess and passageway are positioned to be coincident, fluid is permitted to flow through the passageway and around the rod. The pad is preferably laterally orientable relative to the rod and foldably retractable to within one of the bodies. A solvent is provided for wetting of the pad and solubilizing or suspending the material being sampled from a particular surface. 15 figs.

  9. Centrifuge apparatus

    DOEpatents

    Sartory, Walter K.; Eveleigh, John W.

    1976-01-01

    A method and apparatus for operating a continuous flow blood separation centrifuge are provided. The hematocrit of the entrant whole blood is continuously maintained at an optimum constant value by the addition of plasma to the entrant blood. The hematocrit of the separated red cells is monitored to indicate the degree of separation taking place, thereby providing a basis for regulating the flow through the centrifuge.

  10. CASTING APPARATUS

    DOEpatents

    Gray, C.F.; Thompson, R.H.

    1958-09-23

    An apparatus is described for casting small quantities of uranlum. It consists of a crucible having a hole in the bottom with a mold positioned below. A vertical rcd passes through the hole in the crucible and has at its upper end a piercing head adapted to break the oxide skin encasing a molten uranium body. An air tight cylinder surrounds the crucible and mold, and is arranged to be evacuated.

  11. Hyperthermia apparatus

    DOEpatents

    Larsen, Lawrence E.

    2000-01-01

    A hyperthermia apparatus, suitable for transurethral application, has an energy radiating element comprising a leaky-wave antenna. The leaky wave antenna radiation pattern is characterized by a surface wave which propagates along an aperture formed by openings (small in comparison to a wavelength) in the outer conductor of a transmission line. Appropriate design of the leaky wave antenna produces a uniform, broadside pattern of temperature elevation that uniformly heats all or part of the periurethral tissues.

  12. Incinerator apparatus

    SciTech Connect

    Crawford, J.P.

    1992-10-06

    This patent describes an incinerator apparatus. It comprises: a primary incinerator chamber; a secondary incinerator chamber coupled to the primary incinerator chamber by a passageway; a primary air input into the incinerator chamber; a secondary air input into the secondary incinerator chamber; a plurality of flame detector ports opening into the secondary incinerator chamber and each flame detector port being spaced in a predetermined relationship to each other; and a plurality of ultraviolet flame detectors.

  13. Corrosion fatigue behavior of carbon steel in drilling fluids

    SciTech Connect

    Chaoyang, F.; Jiashen, Z.

    1998-08-01

    Corrosion fatigue of carbon steel (CS) in drilling fluids was studied using a self-made rotary bending corrosion fatigue testing apparatus under simulated drilling conditions. Mechanisms of the effects of cyclic stress, chloride (Cl{sup {minus}}), sulfide (S{sup 2{minus}}), and pH of drilling fluids on corrosion fatigue of CS as well as the inhibiting action of the imidazoline inhibitor and oxygen (O{sub 2}) scavenger sodium sulfite (Na{sub 2}SO{sub 3}) on corrosion fatigue were studied. Results showed Cl{sup {minus}} and S{sup 2{minus}} promoted corrosion fatigue crack initiation and growth. Fatigue life was lengthened after reducing subjected stress, increasing the pH of the drilling fluids, or adding the inhibitor and O{sub 2} scavenger.

  14. Turbocharger apparatus

    SciTech Connect

    Leavesley, M.G.

    1993-08-03

    Variable turbocharger apparatus is described comprising a compressor housing, a compressor mounted for rotation in the compressor housing, a turbine housing, a turbine mounted for rotation in the turbine housing, a first inlet for enabling air to be conducted to the compressor, an outlet for air from the compressor, a second inlet for enabling exhaust gases from an engine to be conducted to the turbine, a chamber which surrounds the turbine and which receives the exhaust gases from the second inlet before the exhaust gases are conducted to the turbine, a piston which is positioned between the turbine and the turbine housing and which is slidable backwards and forwards to form a movable wall separating the turbine from the chamber which surrounds the turbine, a bearing assembly for allowing the rotation of the compressor and the turbine, and a heat shield for shielding the bearing assembly from the exhaust gases, the piston having a plurality of vanes, the piston being such that in its closed position it terminates short of an adjacent part of the turbine housing so that there is always a gap between the end of the piston and the adjacent part of the turbine housing whereby exhaust gases from the chamber can always pass through the gap to act on the turbine, the piston being such that in its open position the gap is increased, and the piston being biased to its closed position against pressure from exhaust gases in the chamber during use of the variable turbocharger apparatus whereby the piston slides backwards and forwards to vary the gap in dependence upon engine operating conditions, and the variable turbocharger apparatus being such that the vanes on the piston enter into slots in the heat shield.

  15. Positioning apparatus

    DOEpatents

    Vogel, Max A.; Alter, Paul

    1986-05-06

    An apparatus for precisely positioning materials test specimens within the optimum neutron flux path emerging from a neutron source located in a housing. The test specimens are retained in a holder mounted on the free end of a support pivotably mounted and suspended from a movable base plate. The support is gravity biased to urge the holder in a direction longitudinally of the flux path against the housing. Means are provided for moving the base plate in two directions to effect movement of the holder in two mutually perpendicular directions normal to the axis of the flux path.

  16. Positioning apparatus

    DOEpatents

    Vogel, Max A.; Alter, Paul

    1986-01-01

    An apparatus for precisely positioning materials test specimens within the optimum neutron flux path emerging from a neutron source located in a housing. The test specimens are retained in a holder mounted on the free end of a support pivotably mounted and suspended from a movable base plate. The support is gravity biased to urge the holder in a direction longitudinally of the flux path against the housing. Means are provided for moving the base plate in two directions to effect movement of the holder in two mutually perpendicular directions normal to the axis of the flux path.

  17. SEPARATION APPARATUS

    DOEpatents

    Huff, J.B.

    1962-03-13

    A furnace apparatus is designed for treating a nuclear reactor waste solution. The solution is sprayed onto a bed of burning petroleum coke which expels water, the more volatile fission products, and nitrogen oxides. Next, chlorine gas is introduced from below which causes aluminum to volatilize as aluminum chloride and along with it certain fission products including Nb/sup 95/ and Zr/sup 95/. These lose their radioactivity within four years and the long- lived radioactivity remains with the ash, which is stored. (AEC) V) nitrate. (P.C.H.)

  18. Detonating apparatus

    DOEpatents

    Johnston, Lawrence H.

    1976-01-01

    1. Apparatus for detonation of high explosive in uniform timing comprising in combination, an outer case, spark gap electrodes insulatedly supported in spaced relationship within said case to form a spark gap, high explosive of the class consisting of pentaerythritol tetranitrate and trimethylene trinitramine substantially free from material sensitive to detonation by impact compressed in surrounding relation to said electrodes including said spark gap under a pressure from about 100 psi to about 500 psi, said spark gap with said compressed explosive therein requiring at least 1000 volts for sparking, and means for impressing at least 1000 volts on said spark gap.

  19. Electrostatic apparatus for measurement of microfracture strength

    DOEpatents

    de Boer, Maarten; Bitsie, Fernando; Jensen, Brian D.

    2002-01-01

    A new class of materials testing apparatus has been invented. Particularly suited to the measurement of fracture and fatigue properties in the extremely strong materials encountered in microelectromechanical systems, material strains well in excess of 1% can be applied pseudostatically, dynamically, or repetitively by these testers. There are no other practical methods to determine these material properties routinely in a process environment, and few alternatives in any circumstances.

  20. Acoustic concentration of particles in fluid flow

    DOEpatents

    Ward, Michael D.; Kaduchak, Gregory

    2010-11-23

    An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.

  1. Method of and apparatus for determining deposition-point temperature

    DOEpatents

    Mansure, A.J.; Spates, J.J.; Martin, S.J.

    1998-10-27

    Acoustic-wave sensor apparatus and method are disclosed for analyzing a normally liquid petroleum-based composition for monitoring deposition-point temperature. The apparatus includes at least one acoustic-wave device such as SAW, QCM, FPM, TSM or APM type devices in contact with the petroleum-based composition for sensing or detecting the surface temperature at which deposition occurs and/or rate of deposition as a function of temperature by sensing an accompanying change in frequency, phase shift, damping voltage or damping current of an electrical oscillator to a known calibrated condition. The acoustic wave device is actively cooled to monitor the deposition of constituents such as paraffins by determining the point at which solids from the liquid composition begin to form on the acoustic wave device. The acoustic wave device can be heated to melt or boil off the deposits to reset the monitor and the process can be repeated. 5 figs.

  2. Method of and apparatus for determining deposition-point temperature

    DOEpatents

    Mansure, Arthur J.; Spates, James J.; Martin, Stephen J.

    1998-01-01

    Acoustic-wave sensor apparatus and method for analyzing a normally liquid petroleum-based composition for monitoring deposition-point temperature. The apparatus includes at least one acoustic-wave device such as SAW, QCM, FPM, TSM or APM type devices in contact with the petroleum-based composition for sensing or detecting the surface temperature at which deposition occurs and/or rate of deposition as a function of temperature by sensing an accompanying change in frequency, phase shift, damping voltage or damping current of an electrical oscillator to a known calibrated condition. The acoustic wave device is actively cooled to monitor the deposition of constituents such as paraffins by determining the point at which solids from the liquid composition begin to form on the acoustic wave device. The acoustic wave device can be heated to melt or boil off the deposits to reset the monitor and the process can be repeated.

  3. Collecting apparatus

    DOEpatents

    Duncan, Charles P.

    1983-01-01

    An improved collecting apparatus for small aquatic or airborne organisms such as plankton, larval fish, insects, etc. The improvement constitutes an apertured removal container within which is retained a collecting bag, and which is secured at the apex of a conical collecting net. Such collectors are towed behind a vessel or vehicle with the open end of the conical net facing forward for trapping the aquatic or airborne organisms within the collecting bag, while allowing the water or air to pass through the apertures in the container. The container is readily removable from the collecting net whereby the collecting bag can be quickly removed and replaced for further sample collection. The collecting bag is provided with means for preventing the bag from being pulled into the container by the water or air flowing therethrough.

  4. Burner apparatus

    SciTech Connect

    Ximpara, N.; Moriya, Y.; Xaneko, H.

    1984-01-31

    The present invention improves a conventional Bunsen burner by providing it with a primary combustion chamber which covers the primary flame forming portion of the Bunsen burner and which has a secondary flame hole immediately above the primary flame forming portion. The burner apparatus of the present invention produces reduced NO /SUB x/ since the overall combustion is divided into primary flame combustion and secondary flame combustion. Further according to the invention, an indication of incomplete combustion due to oxygen deficiency in the ambient air or blockade of the primary air passage can be dependably detected for cessation of combustion by providing a flame rod and measuring the impedance (or ion current) of the rod.

  5. MEASURING APPARATUS

    DOEpatents

    Kohman, T.P.; Weissbourd, B.W.

    1959-02-17

    An ion chamber assembly is presented for measuring neutron emission of a relatively slow rate from a radioactive sample. The detecting apparatus comprises a container filled with neutron slowing material and having a cavity where a neutron source may be located centrally in the container. A plurality of ion chamber units are disposed equidistantly from the source and from each other for detecting the neutron radiation. Each of the ion chamber units has an ion chamber and a second chamber of substantially the same diameter as the ion chamber and in end-to-end relationship therewith. The second chamber contains paraffin and an axially disposed lead-in conductor for the ion chamber central electrode. The preamplifier circuit whose input is connected to the lead-in conductor is housed in a third container arranged in end-to-end relationship with the second chamber.

  6. A method and apparatus for sizing and separating warp yarns

    SciTech Connect

    Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, Apostolos C.; Kupperman, David S.

    1997-12-01

    A slashing process for preparing warp yarns for weaving operations includes the steps of sizing and/or desizing the yarns in an acoustic resonance box and separating the yarns with a leasing apparatus comprised of a set of acoustically agitated lease rods. The sizing step includes immersing the yarns in a size solution contained in an acoustic resonance box. Acoustic transducers are positioned against the exterior of the box for generating an acoustic pressure field within the size solution. Ultrasonic waves that result from the acoustic pressure field continuously agitate the size solution to effect greater mixing and more uniform application and penetration of the size onto the yarns. The sized yarns are then separated by passing the warp yarns over and under lease rods. Electroacoustic transducers generate acoustic waves along the longitudinal axis of the lease rods, creating a shearing motion on the surface of the rods for splitting the yarns.

  7. Development of a thermal acoustical aircraft insulation material

    NASA Technical Reports Server (NTRS)

    Lin, R. Y.; Struzik, E. A.

    1974-01-01

    A process was developed for fabricating a light weight foam suitable for thermal and acoustical insulation in aircraft. The procedures and apparatus are discussed, and the foam specimens are characterized by numerous tests and measurements.

  8. Acoustic Neuroma

    MedlinePlus

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. The tumor ... press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the symptoms ...

  9. Workover rig support apparatus

    SciTech Connect

    Crist, W.W.

    1984-08-28

    An apparatus is claimed for distributing the weight of a workover or maintenance apparatus connected to a Christmas tree over the surface of the portion of the Christmas tree to which the workover apparatus is attached, including a plate which rests upon the portion of the Christmas tree to which the workover apparatus is attached, and a rigid support extending upwardly from the plate, the rigid support being connectable to said workover apparatus. The apparatus may include plugs for plugging the other strings of tubing contained in the Christmas tree to which the workover apparatus is not attached, and devices for adjusting the length of the rigid support.

  10. Attachment Apparatus

    SciTech Connect

    Morrison, Edward F.

    1998-08-18

    The present invention includes an attachment apparatus comprising a rotation limiting member adapted to be threaded onto a threaded member; and a preload nut adapted to be threaded onto the threaded member. The rotation limiting member comprises a plurality of pins; and the preload nut comprises plurality of slots, preferably wherein the plurality of pins and the plurality of slots are the same in number, which is preferably three. The plurality of pins of the rotation limiting member are filled into a corresponding plurality of slots of the preload nut to form a rotatable unit adapted to be threaded onto the threaded member. In use, the rotatable unit is threaded onto the threaded member. The present invention thus provides a unitized removable device for holes, including holes other than circular in shape, which have an established depth before an end of, or before an enlargement of the hole. The configuration of some exposed part of the device, or the head, is shaped and formed for its intended purpose, such as clamping, anchor points, eye bolts, stud anchor, and the like. The device allows for the installation, preloading and removal of all components of the device, as a unit, without damage to the member for which attachment is required by simple rotations of some exposed part of the device.

  11. Wellhead apparatus

    SciTech Connect

    Reimert, L.E.

    1984-08-28

    There are disclosed two embodiments of wellhead apparatus for use in suspending concentric strings of casing of an offshore well at the ocean floor. For this purpose, an inner hanger to which the inner casing is connected is adapted to be landed within an outer hanger to which the outer casing is connected, each at the ocean floor or ''mudline''. Seating surfaces are formed on the bore of the tubular body of the outer hanger body, and landing surfaces are formed on a circumferentially split landing ring arranged about the tubular body of the inner hanger and having landing surfaces formed thereabout for expansion and contraction within a recess about the tubular hanger body between a contracted position as it is moved vertically within the outer casing and bore of the tubular body of the outer hanger, and an expanded position in which the landing surfaces thereon are landed upon the seating surfaces when disposed opposite thereto. The landing ring is retained in a position for expansion and contraction within the recess by detent means which is releasable, when the landing ring is in landed position, and the weight of the inner casing is slacked off so as to lower the inner hanger body into supported position on the landing ring.

  12. Wellhead apparatus

    SciTech Connect

    Reimert, L.E.

    1983-12-27

    There is disclosed apparatus for use in suspending concentric strings of casing of an offshore well at the ocean floor, wherein at least one hanger for suspending an intermediate casing string is provided with a plurality of vertically spaced, upwardly facing seating surfaces which extend radially inwardly from its bore, and the outer side of such hanger body has a recess thereabout in which a radially expandable ring having a plurality of vertically spaced, downwardly facing landing surfaces is received. As the intermediate hanger body is lowered into the bore of an outer hanger having vertically spaced, upwardly facing seating surfaces extending radially outwardly from its bore, the ring expands radially outwardly to move its landing surfaces into supported positions on the seating surfaces of the outer hanger. As an inner hanger is lowered into the bore of the intermediate hanger, landing surfaces on a radially expandible ring carried within a recess about the outer side of its body are caused to expand with the ring into supported positions on the seating surfaces of the intermediate hanger body. The seating surfaces within the bore of the intermediate hanger body and the recess about its outer side in which the expandible ring is received are on generally the same vertical line.

  13. Laser apparatus

    DOEpatents

    Lewis, Owen; Stogran, Edmund M.

    1980-01-01

    Laser apparatus is described wherein an active laser element, such as the disc of a face-pumped laser, is mounted in a housing such that the weight of the element is supported by glass spheres which fill a chamber defined in the housing between the walls of the housing and the edges of the laser element. The uniform support provided by the spheres enable the chamber and the pump side of the laser element to be sealed without affecting the alignment or other optical properties of the laser element. Cooling fluid may be circulated through the sealed region by way of the interstices between the spheres. The spheres, and if desired also the cooling fluid may contain material which absorbs radiation at the wavelength of parasitic emissions from the laser element. These parasitic emissions enter the spheres through the interface along the edge surface of the laser element and it is desirable that the index of refraction of the spheres and cooling fluid be near the index of refraction of the laser element. Thus support, cooling, and parasitic suppression functions are all accomplished through the use of the arrangement.

  14. Acoustic Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  15. Acoustic seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  16. Low cycle fatigue

    NASA Technical Reports Server (NTRS)

    Solomon, H. D. (Editor); Kaisand, L. R. (Editor); Halford, G. R. (Editor); Leis, B. N. (Editor)

    1988-01-01

    The papers contained in this volume focus on various aspects of low cycle fatigue, including cyclic deformation, crack propagation, high-temperature low cycle fatigue, microstructural defects, multiaxial and variable amplitude loading, and life prediction. Papers are presented on the low cycle fatigue of some aluminum alloys, prediction of crack growth under creep-fatigue loading conditions, high-temperature low cycle fatigue behavior and lifetime prediction of a nickel-base ODS alloy, and an integrated approach to creep-fatigue life prediction. Other topics discussed include thermal fatigue testing of coated monocrystalline superalloys, low cycle fatigue of Al-Mg-Si alloys, and the effect of superimposed stresses at high frequency on low cycle fatigue.

  17. Fatigue life prediction of bonded primary joints

    NASA Technical Reports Server (NTRS)

    Knauss, J. F.

    1979-01-01

    The validation of a proposed fatigue life prediction methodology was sought through the use of aluminum butt and scarf joint and graphite/epoxy butt joint specimens in a constant amplitude fatigue environment. The structural properties of the HYSOL 9313 adhesive system were obtained by mechanical test of molded heat adhesive specimens. Aluminum contoured double cantilever beam specimens were used to generate crack velocity versus stress intensity factor data. The specific objectives were: (1) to ascertain the feasibility of predicting fatigue failure of an adhesive in a primary bonded composite structure by incorporating linear elastic crack growth behavior; and (2) to ascertain if acoustic emission and/or compliance measurement techniques can be used to detect flaws.

  18. Systems, Apparatuses, and Methods for Using Durable Adhesively Bonded Joints for Sandwich Structures

    NASA Technical Reports Server (NTRS)

    Smeltzer, III, Stanley S. (Inventor); Lundgren, Eric C. (Inventor)

    2014-01-01

    Systems, methods, and apparatus for increasing durability of adhesively bonded joints in a sandwich structure. Such systems, methods, and apparatus includes an first face sheet and an second face sheet as well as an insert structure, the insert structure having a first insert face sheet, a second insert face sheet, and an insert core material. In addition, sandwich core material is arranged between the first face sheet and the second face sheet. A primary bondline may be coupled to the face sheet(s) and the splice. Further, systems, methods, and apparatus of the present disclosure advantageously reduce the load, provide a redundant path, reduce structural fatigue, and/or increase fatigue life.

  19. Classifying Particles By Acoustic Levitation

    NASA Technical Reports Server (NTRS)

    Barmatz, Martin B.; Stoneburner, James D.

    1983-01-01

    Separation technique well suited to material processing. Apparatus with rectangular-cross-section chamber used to measure equilibrium positions of low-density spheres in gravitational field. Vertical acoustic forces generated by two opposing compression drivers exciting fundamental plane-wave mode at 1.2 kHz. Additional horizontal drivers centered samples along vertical axis. Applications in fusion-target separation, biological separation, and manufacturing processes in liquid or gas media.

  20. Acoustic fault injection tool (AFIT)

    NASA Astrophysics Data System (ADS)

    Schoess, Jeffrey N.

    1999-05-01

    On September 18, 1997, Honeywell Technology Center (HTC) successfully completed a three-week flight test of its rotor acoustic monitoring system (RAMS) at Patuxent River Flight Test Center. This flight test was the culmination of an ambitious 38-month proof-of-concept effort directed at demonstrating the feasibility of detecting crack propagation in helicopter rotor components. The program was funded as part of the U.S. Navy's Air Vehicle Diagnostic Systems (AVDS) program. Reductions in Navy maintenance budgets and available personnel have dictated the need to transition from time-based to 'condition-based' maintenance. Achieving this will require new enabling diagnostic technologies. The application of acoustic emission for the early detection of helicopter rotor head dynamic component faults has proven the feasibility of the technology. The flight-test results demonstrated that stress-wave acoustic emission technology can detect signals equivalent to small fatigue cracks in rotor head components and can do so across the rotating articulated rotor head joints and in the presence of other background acoustic noise generated during flight operation. During the RAMS flight test, 12 test flights were flown from which 25 Gbyte of digital acoustic data and about 15 hours of analog flight data recorder (FDR) data were collected from the eight on-rotor acoustic sensors. The focus of this paper is to describe the CH-46 flight-test configuration and present design details about a new innovative machinery diagnostic technology called acoustic fault injection. This technology involves the injection of acoustic sound into machinery to assess health and characterize operational status. The paper will also address the development of the Acoustic Fault Injection Tool (AFIT), which was successfully demonstrated during the CH-46 flight tests.

  1. [Fatigue and depression].

    PubMed

    Hell, Daniel

    2015-04-22

    Fatigue is characterised in an overview of the literature as a specific phenomenon of depression. Its differential diagnosis is discussed. Distinctions and correspondences to burnout are elaborated. Fatigue is not an obligatory symptom of depressive episodes, although it can contribute to depressive developments. The importance of fatigue in depressive episodes and its therapy is shown with the help of a circular model of depression.

  2. Fatigue of composites

    NASA Technical Reports Server (NTRS)

    Salkind, M. J.

    1972-01-01

    The failure mechanisms in the fatigue of composite materials are analyzed in terms of the requirements for designing fatigue-critical composite structures. Fiber reinforced polymers, fiber reinforced metals, fatigue of composite structures, and composite design considerations are discussed. It is concluded that composite materials offer the engineer the opportunity for tailoring stiffness in different directions for designing dynamic components.

  3. Topological Acoustics

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile

    2015-03-01

    The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers.

  4. Topological acoustics.

    PubMed

    Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile

    2015-03-20

    The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers.

  5. Fatigue damage evaluation of austenitic stainless steel using nonlinear ultrasonic waves in low cycle regime

    SciTech Connect

    Zhang, Jianfeng; Xuan, Fu-Zhen

    2014-05-28

    The interrupted low cycle fatigue test of austenitic stainless steel was conducted and the dislocation structure and fatigue damage was evaluated subsequently by using both transmission electron microscope and nonlinear ultrasonic wave techniques. A “mountain shape” correlation between the nonlinear acoustic parameter and the fatigue life fraction was achieved. This was ascribed to the generation and evolution of planar dislocation structure and nonplanar dislocation structure such as veins, walls, and cells. The “mountain shape” correlation was interpreted successfully by the combined contribution of dislocation monopole and dipole with an internal-stress dependent term of acoustic nonlinearity.

  6. Creep contributes to the fatigue behavior of bovine trabecular bone.

    PubMed

    Bowman, S M; Guo, X E; Cheng, D W; Keaveny, T M; Gibson, L J; Hayes, W C; McMahon, T A

    1998-10-01

    Repetitive, low-intensity loading from normal daily activities can generate fatigue damage in trabecular bone, a potential cause of spontaneous fractures of the hip and spine. Finite element models of trabecular bone (Guo et al., 1994) suggest that both creep and slow crack growth contribute to fatigue failure. In an effort to characterize these damage mechanisms experimentally, we conducted fatigue and creep tests on 85 waisted specimens of trabecular bone obtained from 76 bovine proximal tibiae. All applied stresses were normalized by the previously measured specimen modulus. Fatigue tests were conducted at room temperature; creep tests were conducted at 4, 15, 25, 37, 45, and 53 degrees C in a custom-designed apparatus. The fatigue behavior was characterized by decreasing modulus and increasing hysteresis prior to failure. The hysteresis loops progressively displaced along the strain axis, indicating that creep was also involved in the fatigue process. The creep behavior was characterized by the three classical stages of decreasing, constant, and increasing creep rates. Strong and highly significant power-law relationships were found between cycles-to-failure, time-to-failure, steady-state creep rate, and the applied loads. Creep analyses of the fatigue hysteresis loops also generated strong and highly significant power law relationships for time-to-failure and steady-state creep rate. Lastly, the products of creep rate and time-to-failure were constant for both the fatigue and creep tests and were equal to the measured failure strains, suggesting that creep plays a fundamental role in the fatigue behavior of trabecular bone. Additional analysis of the fatigue strain data suggests that creep and slow crack growth are not separate processes that dominate at high and low loads, respectively, but are present throughout all stages of fatigue.

  7. Fatigue in rheumatic diseases

    PubMed Central

    Sandıkçı, Sevinç Can; Özbalkan, Zeynep

    2015-01-01

    Fatigue is a common and important problem in many diseases including rheumatologic illnesses, and it has a negative impact on health-related quality of life. Fatigue is described as having an impact on multiple aspects of a patient’s life. There is a need for knowledge about causes of and treatments for fatigue to ensure that patient outcomes are improved. There are several effective treatment strategies available for fatigue including pharmacological and non-pharmacological therapies. We aim to provide an overview of fatigue in rheumatologic disorders and some recommendations on its optimal management. PMID:27708942

  8. Cognitive and Physical Fatigue Tasks Enhance Pain, Cognitive Fatigue and Physical Fatigue in People with Fibromyalgia

    PubMed Central

    Dailey, Dana L; Keffala, Valerie J; Sluka, Kathleen A

    2014-01-01

    Objective Fibromyalgia is a condition characterized by chronic widespread muscle pain and fatigue. The primary objective of this study was to determine if pain, perceived cognitive fatigue, and perceived physical fatigue were enhanced in participants with fibromyalgia compared to healthy controls during a cognitive fatigue task, a physical fatigue task and a dual fatigue task. Methods Twenty four people with fibromyalgia and 33 healthy controls completed pain, fatigue and function measures. A cognitive fatigue task (Controlled Oral Word Association Test) and physical fatigue task (Valpar peg test) were done individually and combined for a dual fatigue task. Resting pain, perceived cognitive fatigue and perceived physical fatigue were assessed during each task using visual analogue scales. Function was assessed with shoulder range of motion and grip. Results People with fibromyalgia had significantly higher increases in pain, cognitive fatigue and physical fatigue when compared to healthy controls after completion of a cognitive fatigue task, a physical fatigue task, or a dual fatigue task (p<0.01). People with fibromyalgia performed equivalently on measures of physical performance and cognitive performance on the physical and cognitive fatigue tasks, respectively. Conclusions These data show that people with fibromyalgia show larger increases in pain, perceived cognitive fatigue and perceived physical fatigue to both cognitive and physical fatigue tasks compared to healthy controls. The increases in pain and fatigue during cognitive and physical fatigue tasks could influence subject participation in daily activities and rehabilitation. PMID:25074583

  9. Facial neuroma masquerading as acoustic neuroma.

    PubMed

    Sayegh, Eli T; Kaur, Gurvinder; Ivan, Michael E; Bloch, Orin; Cheung, Steven W; Parsa, Andrew T

    2014-10-01

    Facial nerve neuromas are rare benign tumors that may be initially misdiagnosed as acoustic neuromas when situated near the auditory apparatus. We describe a patient with a large cystic tumor with associated trigeminal, facial, audiovestibular, and brainstem dysfunction, which was suspicious for acoustic neuroma on preoperative neuroimaging. Intraoperative investigation revealed a facial nerve neuroma located in the cerebellopontine angle and internal acoustic canal. Gross total resection of the tumor via retrosigmoid craniotomy was curative. Transection of the facial nerve necessitated facial reanimation 4 months later via hypoglossal-facial cross-anastomosis. Clinicians should recognize the natural history, diagnostic approach, and management of this unusual and mimetic lesion.

  10. Apparatus for detecting leaks

    DOEpatents

    Booth, Eugene T.

    1976-02-24

    A method and apparatus for determining the position of and estimating the size of leaks in an evacuating apparatus comprising the use of a testing gas such as helium or hydrogen flowing around said apparatus whereby the testing gas will be drawn in at the site of any leaks.

  11. Fatigue handbook: Offshore steel structures

    SciTech Connect

    Almarnaess, A.

    1985-01-01

    The contents of this book are: Overview of Offshore Steel Structures; Loads on Ocean Structures; Fracture Mechanics As a Tool in Fatigue Analysis; Basic Fatigue Properties of Welded Joints; Significance of Defects; Improving the Fatigue Strength of Welded Joints; Effects of Marine Environment and Cathodic Protection on Fatigue of Structural Steels Fatigue of Tubular Joints; Unstable Fracture; Fatigue Life Calculations; and Fatigue in Building Codes Background and Applications.

  12. Acoustic paramagnetic logging tool

    DOEpatents

    Vail, III, William B.

    1988-01-01

    New methods and apparatus are disclosed which allow measurement of the presence of oil and water in geological formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleons present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth3 s magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation . The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be preformed in open boreholes and in cased well bores.

  13. Detection of thermal fatigue in composites by second harmonic Lamb waves

    NASA Astrophysics Data System (ADS)

    Li, Weibin; Cho, Younho; Achenbach, Jan D.

    2012-08-01

    Composite materials which are widely used in the aerospace industry, are usually subjected to frequent variation of temperature. Thermal cyclic loading may induce material degradation. Considering the long-term service of aircraft composites and the importance of safety in the aircraft industry, even a little damage that may be accumulative via thermal fatigue is often of great concern. Therefore, there is a demand to develop non-destructive approaches to evaluate thermal fatigue damage in an early stage. Due to the sensitivity of acoustic nonlinearity to micro-damage, the nonlinear ultrasonic technique has been explored as a promising tool for early detection of micro-damage. This paper investigates an experimental scheme for characterizing thermal fatigue damage in composite laminates using second harmonic Lamb waves. The present results show a monotonic increase of acoustic nonlinearity with respect to thermal fatigue cycles. The experimental observation of the correlation between the acoustic nonlinearity and thermal fatigue cycles in carbon/epoxy laminates verifies that nonlinear Lamb waves can be used to assess thermal fatigue damage rendering improved sensitivity over conventional linear feature based non-destructive evaluation techniques. Velocity and attenuation based ultrasonic studies are carried out for comparison with the nonlinear ultrasonic approach and it is found that nonlinear acoustic parameters are more promising indicators of thermal fatigue damage than linear ones.

  14. Analysis of the development and possibilities of the acoustic emission method

    NASA Astrophysics Data System (ADS)

    Malecki, Ignacy

    The phenomenon of acoustic emission has been known for ages, but its practical use only dates back to the early 1960's to 'microseismic observations,' or farther back to the analysis of the acoustic emission generated by metals under stress. Discussed is the expansion of the measurement range by the detection of high frequency acoustic emission signals, the generation of acoustic emission by dislocation movements in metals and the brittle fracture of ceramics, the effect of material fatigue on acoustic emission activity, promising new applications in mining and construction, and efforts to improve acoustic emission transducers. A comparative analysis of trends in the development of acoustic emission techniques over the last 25 years and conclusions concerning the directions of future research are given. A description of ways to improve acoustic emission techniques which primarily focuses on electronic acoustic emission signal processing, extraction, and separation is presented. Phases of acoustic emission activity under conditions of rising stress, the 'life span' and fatigue of a material determined by means of acoustic emission, classification of acoustic emission sources, and analysis of the possibilities of acoustic emission for raw materials, processed materials, mechanical engineering, electronics, power generation, construction, and chemicals and for diagnosing motor vehicles and engineering systems are discussed. The authors also discuss the possibility of using acoustic emission in biology and medicine and the possible applications of acoustic emissions for basic research in physics and chemistry.

  15. Musical Acoustics

    NASA Astrophysics Data System (ADS)

    Gough, Colin

    This chapter provides an introduction to the physical and psycho-acoustic principles underlying the production and perception of the sounds of musical instruments. The first section introduces generic aspects of musical acoustics and the perception of musical sounds, followed by separate sections on string, wind and percussion instruments.

  16. Acoustic metafluids.

    PubMed

    Norris, Andrew N

    2009-02-01

    Acoustic metafluids are defined as the class of fluids that allow one domain of fluid to acoustically mimic another, as exemplified by acoustic cloaks. It is shown that the most general class of acoustic metafluids are materials with anisotropic inertia and the elastic properties of what are known as pentamode materials. The derivation uses the notion of finite deformation to define the transformation of one region to another. The main result is found by considering energy density in the original and transformed regions. Properties of acoustic metafluids are discussed, and general conditions are found which ensure that the mapped fluid has isotropic inertia, which potentially opens up the possibility of achieving broadband cloaking. PMID:19206861

  17. Piezoelectric Bolt Breakers and Bolt Fatigue Testers

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Badescu, Mircea; Bar-Cohen, Yoseph; Barengoltz, Jack; Heckman, Vanessa

    2008-01-01

    catastrophic misfire. In fatigue-testing applications, devices of the proposed type would offer advantages of compactness and low cost, relative to conventional fatigue- testing apparatuses. In both structural- separation and fatigue-testing applications, bolts to be broken or tested could be instrumented with additional ultrasonic transducers for monitoring of pertinent physical properties and of fatigue failure processes.

  18. Multiaxial fatigue low cycle fatigue testing

    NASA Technical Reports Server (NTRS)

    Zamrik, S. Y.

    1985-01-01

    Multiaxial testing methods are reviewed. Advantages and disadvantages of each type test is discussed. Significant multiaxial data available in the literature is analyzed. The yield theories are compared for multiaxial fatigue analysis.

  19. High-temperature acoustic test facilities and methods

    NASA Astrophysics Data System (ADS)

    Pearson, Jerome

    1994-09-01

    The Wright Laboratory is the Air Force center for air vehicles, responsible for developing advanced technology and incorporating it into new flight vehicles and for continuous technological improvement of operational air vehicles. Part of that responsibility is the problem of acoustic fatigue. With the advent of jet aircraft in the 1950's, acoustic fatigue of aircraft structure became a significant problem. In the 1960's the Wright Laboratory constructed the first large acoustic fatigue test facilities in the United States, and the laboratory has been a dominant factor in high-intensity acoustic testing since that time. This paper discusses some of the intense environments encountered by new and planned Air Force flight vehicles, and describes three new acoustic test facilities of the Wright Laboratory designed for testing structures in these dynamic environments. These new test facilities represent the state of the art in high-temperature, high-intensity acoustic testing and random fatigue testing. They will allow the laboratory scientists and engineers to test the new structures and materials required to withstand the severe environments of captive-carry missiles, augmented lift wings and flaps, exhaust structures of stealth aircraft, and hypersonic vehicle structures well into the twenty-first century.

  20. Method and Apparatus to Access Optimum Strength During Processing of Precipitation Strengthened Alloys

    NASA Technical Reports Server (NTRS)

    Cantrell, John H. (Inventor); Yost, William T. (Inventor)

    2001-01-01

    A method and apparatus are provided which enable the nondestructive testing of strength of a heat treated alloy. An alloy is insonified with an ultrasonic signal. The resulting convoluted signal is detected and the acoustic nonlinearity parameter is determined. The acoustic nonlinearity parameter shows a peak corresponding to a peak in material strength.

  1. Method and apparatus for remote sensing of molecular species at nanoscale utilizing a reverse photoacoustic effect

    DOEpatents

    Su, Ming [Oviedo, FL; Thundat, Thomas G [Knoxville, TN; Hedden, David [Lenoir City, TN

    2010-02-23

    A method and apparatus for identifying a sample, involves illuminating the sample with light of varying wavelengths, transmitting an acoustic signal against the sample from one portion and receiving a resulting acoustic signal on another portion, detecting a change of phase in the acoustic signal corresponding to the light of varying wavelengths, and analyzing the change of phase in the acoustic signal for the varying wavelengths of illumination to identify the sample. The apparatus has a controlled source for illuminating the sample with light of varying wavelengths, a transmitter for transmitting an acoustic wave, a receiver for receiving the acoustic wave and converting the acoustic wave to an electronic signal, and an electronic circuit for detecting a change of phase in the acoustic wave corresponding to respective ones of the varying wavelengths and outputting the change of phase for the varying wavelengths to allow identification of the sample. The method and apparatus can be used to detect chemical composition or visual features. A transmission mode and a reflection mode of operation are disclosed. The method and apparatus can be applied at nanoscale to detect molecules in a biological sample.

  2. Clinical neurophysiology of fatigue.

    PubMed

    Zwarts, M J; Bleijenberg, G; van Engelen, B G M

    2008-01-01

    Fatigue is a multidimensional concept covering both physiological and psychological aspects. Chronic fatigue is a typical symptom of diseases such as cancer, multiple sclerosis (MS), Parkinson's disease (PD) and cerebrovascular disorders but is also presented by people in whom no defined somatic disease has been established. If certain criteria are met, chronic fatigue syndrome can be diagnosed. The 4-item Abbreviated Fatigue Questionnaire allows the extent of the experienced fatigue to be assessed with a high degree of reliability and validity. Physiological fatigue has been well defined and originates in both the peripheral and central nervous system. The condition can be assessed by combining force and surface-EMG measurements (including frequency analyses and muscle-fibre conduction estimations), twitch interpolation, magnetic stimulation of the motor cortex and analysis of changes in the readiness potential. Fatigue is a well-known phenomenon in both central and peripheral neurological disorders. Examples of the former conditions are multiple sclerosis, Parkinson's disease and stroke. Although it seems to be a universal symptom of many brain disorders, the unique characteristics of the concomitant fatigue also point to a specific relationship with several of these syndromes. As regards neuromuscular disorders, fatigue has been reported in patients with post-polio syndrome, myasthenia gravis, Guillain-Barré syndrome, facioscapulohumeral dystrophy, myotonic dystrophy and hereditary motor and sensory neuropathy type-I. More than 60% of all neuromuscular patients suffer from severe fatigue, a prevalence resembling that of patients with MS. Except for several rare myopathies with specific metabolic derangements leading to exercise-induced muscle fatigue, most studies have not identified a prominent peripheral cause for the fatigue in this population. In contrast, the central activation of the diseased neuromuscular system is generally found to be suboptimal. The

  3. The use of ultrasonic signals and optical method to estimate the damage of materials after fatigue loading

    NASA Astrophysics Data System (ADS)

    Mishakin, V. V.; Mitenkov, F. M.; Klyushnikov, V. A.; Danilova, N. V.

    2010-12-01

    The influence of fatigue load of steels on parameters of ultrasonic and microplastic characteristics has been studied. A phenomenological theory, which connects process of damage accumulation (before appearance of crack) under fatigue loading with acoustic parameters and microplastic parameters, has been developed. Experimental studies showed that the combination of nondestructive methods of control (acoustical and optical) allows one to estimate the state of materials at an early stage of destruction in both low-cycle and high-cycle areas.

  4. The effect of kinesiotape on dynamic balance following muscle fatigue in individuals with chronic ankle instability.

    PubMed

    Kodesh, Einat; Dar, Gali

    2015-01-01

    This study aimed to evaluate the effect of kinesiotape (KT) on dynamic stability following ankle muscle fatigue among individuals with chronic ankle instability (CAI). Twenty participants with CAI participated in the study. Participants were tested under three conditions: KT, non-elastic tape, and no tape pre- and post-fatigue of the ankle muscles. Ankle muscles fatigue was induced using an isokinetic apparatus, activity of the fibularis muscle was recorded using one-channel vibromyography (VMG), and dynamic balance and neuromuscular control were assessed using the Y-Balance Test. Following fatigue exercises, the VMG signal significantly decreased in all groups (p < 0.01), without differences between groups. No significant difference in dynamic balance test scores was found between the pre- and post-fatigue condition for each group and between groups. Our results demonstrate that KT had no significant effects on dynamic balance and muscle activity following ankle muscle fatigue among individuals with CAI. PMID:26279271

  5. Portable containment sleever apparatus

    DOEpatents

    Rea, Michael J.; Brown, Roger A.

    2000-01-01

    A sleever apparatus includes an inner member with a central passage through which an item to be sleeved is passed. An outer member surrounds the inner member and defines a space between the members for holding a supply of containment material, which is preferably plastic sleeving. The apparatus has a handle which allows a user to hold the apparatus and walk the apparatus along the length of the item to be sleeved. As the user passes the item through the sleever apparatus, the containment material exits through a slit at one end of the apparatus in order to contain the item. The sleever apparatus may be formed of disposable materials, such as cardboard, and may be intended for a single use application. Alternatively, the sleever apparatus may be comprised of more permanent materials such as PVC or fiberglass. The sleever apparatus may include a serrated end for cutting the containment material and may include appropriate tubing and valves for either directing an inert gas into the containment material around the item or for withdrawing air from within the containment material in order to create a vacuum. In one embodiment, the sleever apparatus has a cartridge that can be replaced with another cartridge once the supply of the containment material has been depleted.

  6. Brittleness Effect on Rock Fatigue Damage Evolution

    NASA Astrophysics Data System (ADS)

    Nejati, Hamid Reza; Ghazvinian, Abdolhadi

    2014-09-01

    The damage evolution mechanism of rocks is one of the most important aspects in studying of rock fatigue behavior. Fatigue damage evolution of three rock types (onyx marble, sandstone and soft limestone) with different brittleness were considered in the present study. Intensive experimental tests were conducted on the chosen rock samples and acoustic emission (AE) sensors were used in some of them to monitor the fracturing process. Experimental tests indicated that brittleness strongly influences damage evolution of rocks in the course of static and dynamic loading. AE monitoring revealed that micro-crack density induced by the applied loads during different stages of the failure processes increases as rock brittleness increases. Also, results of fatigue tests on the three rock types indicated that the rock with the most induced micro-cracks during loading cycles has the least fatigue life. Furthermore, the condition of failure surfaces of the studied rocks samples, subjected to dynamic and static loading, were evaluated and it was concluded that the roughness of failure surfaces is influenced by loading types and rock brittleness. Dynamic failure surfaces were rougher than static ones and low brittle rock demonstrate a smoother failure surface compared to high brittle rock.

  7. Acoustic trauma

    MedlinePlus

    Acoustic trauma is a common cause of sensory hearing loss . Damage to the hearing mechanisms within the inner ... Symptoms include: Partial hearing loss that most often involves ... The hearing loss may slowly get worse. Noises, ringing in ...

  8. Acoustic Neuroma

    MedlinePlus

    ... slow growing tumor which arise primarily from the vestibular portion of the VIII cranial nerve and lie ... you have a "brain tumor" called acoustic neuroma (vestibular schwannoma). You think you are the only one ...

  9. Underwater Acoustics.

    ERIC Educational Resources Information Center

    Creasey, D. J.

    1981-01-01

    Summarizes the history of underwater acoustics and describes related research studies and teaching activities at the University of Birmingham (England). Also includes research studies on transducer design and mathematical techniques. (SK)

  10. Room Acoustics

    NASA Astrophysics Data System (ADS)

    Kuttruff, Heinrich; Mommertz, Eckard

    The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.

  11. Battery cell feedthrough apparatus

    DOEpatents

    Kaun, Thomas D.

    1995-01-01

    A compact, hermetic feedthrough apparatus comprising interfitting sleeve portions constructed of chemically-stable materials to permit unique battery designs and increase battery life and performance.

  12. Using the Acoustic Emission Technique for Estimating Body Composition

    NASA Astrophysics Data System (ADS)

    González-Solís, J. L.; Sanchis-Sabater, A.; Sosa-Aquino, M.; Gutiérrez-Juárez, G.; Vargas-Luna, M.; Bernal-Alvarado, J.; Huerta-Franco, R.

    2003-09-01

    This work proposes a new technique for estimation of body composition by using acoustic emission. A simple apparatus for the acoustic emission is proposed.The estimation of the body composition is made by analyzing the correlation between a set of acoustic resonance and skinfold measurements. One device was designed to measure the position and width of the acoustic resonances and a caliper was used to measure the skinfolds. The results show the plausibility of application of the method to measurement the human body fat.

  13. Aerodynamic Heating and Fatigue

    NASA Technical Reports Server (NTRS)

    Kroll, Wilhelmina D.

    1959-01-01

    A review of the physical condition's under which future airplanes will operate has been made and the necessity for considering fatigue in the design has been established. A survey of the literature shows what phases of elevated-temperature fatigue have been investigated. Other studies that would yield data of particular interest to the designer of aircraft structures are indicated.

  14. Elevated temperature biaxial fatigue

    NASA Technical Reports Server (NTRS)

    Jordan, E. H.

    1984-01-01

    A three year experimental program for studying elevated temperature biaxial fatigue of a nickel based alloy Hastelloy-X has been completed. A new high temperature fatigue test facility with unique capabilities has been developed. Effort was directed toward understanding multiaxial fatigue and correlating the experimental data to the existing theories of fatigue failure. The difficult task of predicting fatigue lives for non-proportional loading was used as an ultimate test for various life prediction methods being considered. The primary means of reaching improved undertanding were through several critical non-proportional loading experiments. It was discovered that the cracking mode switched from primarily cracking on the maximum shear planes at room temperature to cracking on the maximum normal strain planes at 649 C.

  15. Heating apparatus comprising a heat recovery apparatus

    SciTech Connect

    Pibernat, T.

    1983-08-09

    A heating apparatus includes at least one combustion air inlet, a reverse-draft hearth having a grill positioned within a hearth plate, an ash receptacle for recovering combustion wastes, a fume outlet combustion chamber positoned under the reverse-draft hearth, and a heat recovery device. A heat transport and exchange fluid is adapted to be fed through the heat recovery device, and it circulates through the device in order to recover heat generated in the hearth. The heat recovery device also includes at least one casing positioned beneath the hearth, over the ash receptacle, and which is spaced from the walls of the heating apparatus. The rear portion of the casing is connected to the hearth plate so as to block combustion gases so that the combustion gases will pass over and thereafter under the casing prior to leaving the apparatus via the fume outlet.

  16. Apparatuses and methods for tuning center frequencies

    DOEpatents

    Wojciechowski, Kenneth; Olsson, Roy H.

    2016-02-23

    Apparatuses and methods for tuning center frequencies are described herein. Examples of tuning described herein including tuning using feedback from the resonator. Variable gain feedback for tuning of acoustic wave resonators is provided in some examples. An example apparatus may include a resonator and a feedback loop. The resonator may be configured to receive a tuning signal and to provide a feedback signal. The feedback signal may be based on the tuning signal. The feedback loop may be configured to receive the feedback signal from the resonator. The feedback loop further may be configured to provide the tuning signal to actively tune a center frequency of the resonator. The tuning signal may be based on the feedback signal.

  17. Nonlinear analyses of composite aerospace structures in sonic fatigue

    NASA Technical Reports Server (NTRS)

    Mei, Chuh

    1993-01-01

    This report summarizes the semiannual research progress, accomplishments, and future plans performed under the NASA Langley Research Center Grant No. NAG-1-1358. The primary research effort of this project is the development of analytical methods for the prediction of nonlinear random response of composite aerospace structures subjected to combined acoustic and thermal loads. The progress, accomplishments, and future plates on four sonic fatigue research topics are described. The sonic fatigue design and passive control of random response of shape memory alloy hybrid composites presented in section 4, which is suited especially for HSCT, is a new initiative.

  18. Apparatus for treating garbage

    SciTech Connect

    Chen, C.L.; Chen, K.; Hsien, K.

    1994-01-11

    An apparatus for treating garbage is described. The apparatus has a conveyor, a continuous incinerator receiving garbage from the conveyor, a device for cooling ash carried out of the continuous incinerator, a device for filtering the ash, a pipe for inducing exhaust from the continuous incinerator to a water tank for removing particles and water-soluble components from the exhaust. 1 fig.

  19. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1981-01-01

    Describes: (1) a variable inductor suitable for an inductance-capacitance bridge consisting of a fixed cylindrical solenoid and a moveable solenoid; (2) long-range apparatus for demonstrating falling bodies; and (3) an apparatus using two lasers to demonstrate ray optics. (SK)

  20. Aerosol distribution apparatus

    DOEpatents

    Hanson, W.D.

    An apparatus for uniformly distributing an aerosol to a plurality of filters mounted in a plenum, wherein the aerosol and air are forced through a manifold system by means of a jet pump and released into the plenum through orifices in the manifold. The apparatus allows for the simultaneous aerosol-testing of all the filters in the plenum.

  1. Thermal protection apparatus

    DOEpatents

    Bennett, G.A.; Elder, M.G.; Kemme, J.E.

    1984-03-20

    The disclosure is directed to an apparatus for thermally protecting sensitive components in tools used in a geothermal borehole. The apparatus comprises a Dewar within a housing. The Dewar contains heat pipes such as brass heat pipes for thermally conducting heat from heat sensitive components such as electronics to a heat sink such as ice.

  2. Thermal protection apparatus

    DOEpatents

    Bennett, Gloria A.; Elder, Michael G.; Kemme, Joseph E.

    1985-01-01

    An apparatus which thermally protects sensitive components in tools used in a geothermal borehole. The apparatus comprises a Dewar within a housing. The Dewar contains heat pipes such as brass heat pipes for thermally conducting heat from heat sensitive components to a heat sink such as ice.

  3. Acoustic biosensors

    PubMed Central

    Fogel, Ronen; Seshia, Ashwin A.

    2016-01-01

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. PMID:27365040

  4. Acoustic biosensors.

    PubMed

    Fogel, Ronen; Limson, Janice; Seshia, Ashwin A

    2016-06-30

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. PMID:27365040

  5. Sliding contact fatigue damage in layered ceramic structures.

    PubMed

    Kim, J-W; Kim, J-H; Thompson, V P; Zhang, Y

    2007-11-01

    Porcelain-veneered restorations often chip and fracture from repeated occlusal loading, making fatigue studies relevant. Most fatigue studies are limited to uni-axial loading without sliding motion. We hypothesized that bi-axial loading (contact-load-slide-liftoff, simulating a masticatory cycle), as compared with uni-axial loading, accelerates the fatigue of layered ceramics. Monolithic glass plates were epoxy-joined to polycarbonate substrates as a transparent model for an all-ceramic crown on dentin. Uni-and bi-axial cyclic contact was applied through a hard sphere in water, by means of a mouth-motion simulator apparatus. The uni-axial (contact-load-hold-liftoff) and traditional R-ratio fatigue (indenter never leaves the specimen surface) produced similar lifespans, while bi-axial fatigue was more severe. The accelerated crack growth rate in bi-axial fatigue is attributed to enhanced tensile stresses at the trailing edges of a moving indenter. Fracture mechanics descriptions for damage evolution in brittle materials loaded repeatedly with a sliding sphere are provided. Clinical relevance is addressed.

  6. Filtering apparatus and method of use

    NASA Technical Reports Server (NTRS)

    Gavalas, Lillian Susan (Inventor)

    2011-01-01

    A filtering apparatus comprises a microporous membrane and an actuator. The membrane is positioned to traverse across the hollow interior of a conduit used for the transport of molecules in bulk. In one example, the pores of the membrane comprise a plurality of open-ended carbon nanotubes. The actuator comprises a transducing material such as a polyvinyledene fluoride film that is operatively positioned in contact with the membrane and is capable of propagating acoustic vibration onto the membrane at a particular frequency so as to hasten the movement of the molecules through the membrane. Similarly, a method of filtering water comprises the steps of: (a) sifting molecules of water through the membrane, the pores of the membrane comprising a plurality of carbon nanotubes; and (b) propagating acoustic vibration onto the microporous membrane at a libration frequency of ice so as to hasten movement of the water molecules within the carbon nanotubes.

  7. Elevated temperature biaxial fatigue

    NASA Technical Reports Server (NTRS)

    Jordan, E. H.

    1985-01-01

    A 3 year experimental program for studying elevated temperature biaxial fatigue of a nickel based alloy Hastelloy-X has been completed. A new high temperature fatigue test facility with unique capabilities has been developed. Effort was directed toward understanding multiaxial fatigue and correlating the experimental data to the existing theories of fatigue failure. The difficult task of predicting fatigue lives for nonproportional loading was used as an ultimate test for various life prediction methods being considered. The primary means of reaching improved understanding were through several critical nonproportional loading experiments. The direction of cracking observed on failed specimens was also recorded and used to guide the development of the theory. Cyclic deformation responses were permanently recorded digitally during each test. It was discovered that the cracking mode switched from primarily cracking on the maximum shear planes at room temperature to cracking on the maximum normal strain planes at 649 C. In contrast to some other metals, loading path in nonproportional loading had little effect on fatigue lives. Strain rate had a small effect on fatigue lives at 649 C. Of the various correlating parameters the modified plastic work and octahedral shear stress were the most successful.

  8. Cylindrical acoustic levitator/concentrator

    DOEpatents

    Kaduchak, Gregory; Sinha, Dipen N.

    2002-01-01

    A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that of the interior cavity of the cylinder. When the resonance frequency of the interior cylindrical cavity is matched to the breathing mode resonance of the cylindrical piezoelectric transducer, the acoustic efficiency for establishing a standing wave pattern in the cavity is high. The cylinder does not require accurate alignment of a resonant cavity. Water droplets having diameters greater than 1 mm have been levitated against the force of gravity using; less than 1 W of input electrical power. Concentration of aerosol particles in air is also demonstrated.

  9. The measurement of fatigue: a new instrument.

    PubMed

    Schwartz, J E; Jandorf, L; Krupp, L B

    1993-10-01

    Fatigue is a frequent medical symptom which has not been routinely measured. We present a 29-item fatigue assessment instrument, describe its psychometric properties, and use it to differentiate normal fatigue from fatigue related medical disorders. Differences in fatigue across a variety of medical disorders, the reproducibility of the fatigue instrument, and its convergent validity with other fatigue measures are also described.

  10. Elevated Temperature Fatigue Endurance of Three Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Verrilli, Michael J.

    2007-01-01

    High-cycle fatigue endurance of three candidate materials for the acoustic liners of the Enabling Propulsion Materials Nozzle Program was investigated. The ceramic matrix composite materials investigated were N720/AS (Nextel 720, 3M Corporation), Sylramic S200 (Dow Corning), and UT 22. High-cycle fatigue tests were conducted in air at 910 C on as-machined specimens and on specimens subjected to tensile cyclic load excursions every 160 hr followed by thermal exposure at 910 C in a furnace up to total exposure times of 2066 and 4000 hr. All the fatigue tests were conducted in air at 100 Hz with a servohydraulic test machine. In the as-machined condition, among the three materials investigated only the Sylramic S200 exhibited a deterministic type of high-cycle fatigue behavior. Both the N720/AS and UT-22 exhibited significant scatter in the experimentally observed high-cycle fatigue lives. Among the thermally exposed specimens, N720/AS and Sylramic S200 materials exhibited a reduction in the high-cycle fatigue lives, particularly at the exposure time of 4000 hr.

  11. Acoustic Levitator With Furnace And Laser Heating

    NASA Technical Reports Server (NTRS)

    Barmatz, Martin B.; Stoneburner, James D.

    1991-01-01

    Acoustic-levitation apparatus incorporates electrical-resistance furnace for uniform heating up to temperature of about 1,000 degrees C. Additional local heating by pair of laser beams raise temperature of sample to more than 1,500 degrees C. High temperature single-mode acoustic levitator generates cylindrical-mode accoustic resonance levitating sample. Levitation chamber enclosed in electrical-resistance furnace. Infrared beams from Nd:YAG laser provide additional local heating of sample. Designed for use in containerless processing of materials in microgravity or in normal Earth gravity.

  12. Acoustic imaging in a water filled metallic pipe

    SciTech Connect

    Kolbe, W.F.; Turko, B.T.; Leskovar, B.

    1984-04-01

    A method is described for the imaging of the interior of a water filled metallic pipe using acoustical techniques. The apparatus consists of an array of 20 acoustic transducers mounted circumferentially around the pipe. Each transducer is pulsed in sequence, and the echos resulting from bubbles in the interior are digitized and processed by a computer to generate an image. The electronic control and digitizing system and the software processing of the echo signals are described. The performance of the apparatus is illustrated by the imaging of simulated bubbles consisting of thin walled glass spheres suspended in the pipe.

  13. On the interaction of ultrasound with cracks: Applications to fatigue crack growth

    NASA Technical Reports Server (NTRS)

    Buck, O.; Thompson, R. B.; Rehbein, D. K.

    1986-01-01

    Partial contact of two rough fatigue crack surfaces leads to transmission and diffraction of an acoustic signal at those contacts. Recent experimental and theoretical efforts to understand and quantify such contact in greater detail are discussed. The objective is to develop an understanding of the closure phenomenon and its application to the interpretation of fatigue data, in particular the R-ratio, spike overload/underload and threshold effects on crack propagation.

  14. Mirror plasma apparatus

    DOEpatents

    Moir, Ralph W.

    1981-01-01

    A mirror plasma apparatus which utilizes shielding by arc discharge to form a blanket plasma and lithium walls to reduce neutron damage to the wall of the apparatus. An embodiment involves a rotating liquid lithium blanket for a tandem mirror plasma apparatus wherein the first wall of the central mirror cell is made of liquid lithium which is spun with angular velocity great enough to keep the liquid lithium against the first material wall, a blanket plasma preventing the lithium vapor from contaminating the plasma.

  15. CASTING METHOD AND APPARATUS

    DOEpatents

    Gray, C.F.; Thompson, R.H.

    1958-10-01

    An improved apparatus for the melting and casting of uranium is described. A vacuum chamber is positioned over the casting mold and connected thereto, and a rod to pierce the oxide skin of the molten uranium is fitted into the bottom of the melting chamber. The entire apparatus is surrounded by a jacket, and operations are conducted under a vacuum. The improvement in this apparatus lies in the fact that the top of the melting chamber is fitted with a plunger which allows squeezing of the oxide skin to force out any molten uranium remaining after the skin has been broken and the molten charge has been cast.

  16. Cleaning method and apparatus

    DOEpatents

    Jackson, D.D.; Hollen, R.M.

    1981-02-27

    A method of very thoroughly and quikcly cleaning a guaze electrode used in chemical analyses is given, as well as an automobile cleaning apparatus which makes use of the method. The method generates very little waste solution, and this is very important in analyzing radioactive materials, especially in aqueous solutions. The cleaning apparatus can be used in a larger, fully automated controlled potential coulometric apparatus. About 99.98% of a 5 mg plutonium sample was removed in less than 3 minutes, using only about 60 ml of rinse solution and two main rinse steps.

  17. Pipe crawler apparatus

    DOEpatents

    Hovis, Gregory L.; Erickson, Scott A.; Blackmon, Bruce L.

    2002-01-01

    A pipe crawler apparatus particularly useful for 3-inch and 4-inch diameter pipes is provided. The pipe crawler apparatus uses a gripping apparatus in which a free end of a piston rod is modified with a bearing retaining groove. Bearings, placed within the groove, are directed against a camming surface of three respective pivoting support members. The non-pivoting ends of the support members carry a foot-like gripping member that, upon pivoting of the support member, engages the interior wall of the pipe.

  18. Nuclear reactor apparatus

    DOEpatents

    Wade, Elman E.

    1978-01-01

    A lifting, rotating and sealing apparatus for nuclear reactors utilizing rotating plugs above the nuclear reactor core. This apparatus permits rotation of the plugs to provide under the plug refueling of a nuclear core. It also provides a means by which positive top core holddown can be utilized. Both of these operations are accomplished by means of the apparatus lifting the top core holddown structure off the nuclear core while stationary, and maintaining this structure in its elevated position during plug rotation. During both of these operations, the interface between the rotating member and its supporting member is sealingly maintained.

  19. Conduit grinding apparatus

    DOEpatents

    Nachbar, Henry D.; Korytkowski, Alfred S.

    1991-01-01

    A grinding apparatus for grinding the interior portion of a valve stem receiving area of a valve. The apparatus comprises a faceplate, a plurality of cams mounted to an interior face of the faceplate, a locking bolt to lock the faceplate at a predetermined position on the valve, a movable grinder and a guide tube for positioning an optical viewer proximate the area to be grinded. The apparatus can either be rotated about the valve for grinding an area of the inner diameter of a valve stem receiving area or locked at a predetermined position to grind a specific point in the receiving area.

  20. AUTOMATIC COUNTING APPARATUS

    DOEpatents

    Howell, W.D.

    1957-08-20

    An apparatus for automatically recording the results of counting operations on trains of electrical pulses is described. The disadvantages of prior devices utilizing the two common methods of obtaining the count rate are overcome by this apparatus; in the case of time controlled operation, the disclosed system automatically records amy information stored by the scaler but not transferred to the printer at the end of the predetermined time controlled operations and, in the case of count controlled operation, provision is made to prevent a weak sample from occupying the apparatus for an excessively long period of time.

  1. Chronic fatigue syndrome

    MedlinePlus

    Bennett RM. Fibromyalgia, chronic fatigue syndrome, and myofascial pain. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 274. Engleberg NC. Chronic ...

  2. Fatigue and Multiple Sclerosis

    MedlinePlus

    Fatigue - National Multiple Sclerosis Society Skip to navigation Skip to content Menu Navigation National Multiple Sclerosis Society Sign In In Your Area ... help* daily life for: positive-mom* The National MS Society is Here to Help Need More Information? ...

  3. Brain Tumors and Fatigue

    MedlinePlus

    ... tiredness. You may experience a profound lack of energy that can come on suddenly and bring dramatic ... to manage the severity. Respect the Fatigue The energy you’re accustomed to having has been transferred ...

  4. Material fabrication using acoustic radiation forces

    DOEpatents

    Sinha, Naveen N.; Sinha, Dipen N.; Goddard, Gregory Russ

    2015-12-01

    Apparatus and methods for using acoustic radiation forces to order particles suspended in a host liquid are described. The particles may range in size from nanometers to millimeters, and may have any shape. The suspension is placed in an acoustic resonator cavity, and acoustical energy is supplied thereto using acoustic transducers. The resulting pattern may be fixed by using a solidifiable host liquid, forming thereby a solid material. Patterns may be quickly generated; typical times ranging from a few seconds to a few minutes. In a one-dimensional arrangement, parallel layers of particles are formed. With two and three dimensional transducer arrangements, more complex particle configurations are possible since different standing-wave patterns may be generated in the resonator. Fabrication of periodic structures, such as metamaterials, having periods tunable by varying the frequency of the acoustic waves, on surfaces or in bulk volume using acoustic radiation forces, provides great flexibility in the creation of new materials. Periodicities may range from millimeters to sub-micron distances, covering a large portion of the range for optical and acoustical metamaterials.

  5. The formation method of the feature space for the identification of fatigued bills

    NASA Astrophysics Data System (ADS)

    Kang, Dongshik; Oshiro, Ayumu; Ozawa, Kenji; Mitsui, Ikugo

    2014-10-01

    Fatigued bills make a trouble such as the paper jam in a bill handling machine. In the discrimination of fatigued bills using an acoustic signal, the variation of an observed bill sound is considered to be one of causes in misclassification. Therefore a technique has demanded in order to make the classification of fatigued bills more efficient. In this paper, we proposed the algorithm that extracted feature quantity of bill sound from acoustic signal using the frequency difference, and carried out discrimination experiment of fatigued bill money by Support Vector Machine(SVM). The feature quantity of frequency difference can represent the frequency components of an acoustic signal is varied by the fatigued degree of bill money. The generalization performance of SVM does not depend on the size of dimensions of the feature space, even in a high dimensional feature space such as bill-acoustic signals. Furthermore, SVM can induce an optimal classifier which considers the combination of features by the virtue of polynomial kernel functions.

  6. Fatigue loading of tendon

    PubMed Central

    Shepherd, Jennifer H; Screen, Hazel R C

    2013-01-01

    Tendon injuries, often called tendinopathies, are debilitating and painful conditions, generally considered to develop as a result of tendon overuse. The aetiology of tendinopathy remains poorly understood, and whilst tendon biopsies have provided some information concerning tendon appearance in late-stage disease, there is still little information concerning the mechanical and cellular events associated with disease initiation and progression. Investigating this in situ is challenging, and numerous models have been developed to investigate how overuse may generate tendon fatigue damage and how this may relate to tendinopathy conditions. This article aims to review these models and our current understanding of tendon fatigue damage. We review the strengths and limitations of different methodologies for characterizing tendon fatigue, considering in vitro methods that adopt both viable and non-viable samples, as well as the range of different in vivo approaches. By comparing data across model systems, we review the current understanding of fatigue damage development. Additionally, we compare these findings with data from tendinopathic tissue biopsies to provide some insights into how these models may relate to the aetiology of tendinopathy. Fatigue-induced damage consistently highlights the same microstructural, biological and mechanical changes to the tendon across all model systems and also correlates well with the findings from tendinopathic biopsy tissue. The multiple testing routes support matrix damage as an important contributor to tendinopathic conditions, but cellular responses to fatigue appear complex and often contradictory. PMID:23837793

  7. Directional electrostatic accretion process employing acoustic droplet formation

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C. (Inventor)

    1996-01-01

    The present invention is directed to an apparatus for manufacturing a free standing solid metal part. In the present invention metal droplets are produced from a free surface pool of molten metal is when an acoustic wave impacts an acoustic lens that is contiguous with the free standing pool of molten metal. The metal droplets are then charged and deflected toward a target. The build up of the metal droplets combine to form the free standing solid metal part.

  8. Non-contact transportation using near-field acoustic levitation

    PubMed

    Ueha; Hashimoto; Koike

    2000-03-01

    Near-field acoustic levitation, where planar objects 10 kg in weight can levitate stably near the vibrating plate, is successfully applied both to non-contact transportation of objects and to a non-contact ultrasonic motor. Transporting apparatuses and an ultrasonic motor have been fabricated and their characteristics measured. The theory of near-field acoustic levitation both for a piston-like sound source and a flexural vibration source is also briefly described. PMID:10829622

  9. Piezoelectric Shunt Vibration Damping of F-15 Panel under High Acoustic Excitation

    NASA Technical Reports Server (NTRS)

    Wu, Shu-Yau; Turner, Travis L.; Rizzi, Stephen A.

    2000-01-01

    At last year's SPIE symposium, we reported results of an experiment on structural vibration damping of an F-15 underbelly panel using piezoelectric shunting with five bonded PZT transducers. The panel vibration was induced with an acoustic speaker at an overall sound pressure level (OASPL) of about 90 dB. Amplitude reductions of 13.45 and 10.72 dB were achieved for the first and second modes, respectively, using single- and multiple-mode shunting. It is the purpose of this investigation to extend the passive piezoelectric shunt-damping technique to control structural vibration induced at higher acoustic excitation levels, and to examine the controllability and survivability of the bonded PZT transducers at these high levels. The shunting experiment was performed with the Thermal Acoustic Fatigue Apparatus (TAFA) at the NASA Langley Research Center using the same F-15 underbelly panel. The TAFA is a progressive wave tube facility. The panel was mounted in one wall of the TAFA test section using a specially designed mounting fixture such that the panel was subjected to grazing-incidence acoustic excitation. Five PZT transducers were used with two shunt circuits designed to control the first and second modes of the structure between 200 and 400 Hz. We first determined the values of the shunt inductance and resistance at an OASPL of 130 dB. These values were maintained while we gradually increased the OASPL from 130 to 154 dB in 6-dB steps. During each increment, the frequency response function between accelerometers on the panel and the acoustic excitation measured by microphones, before and after shunting, were recorded. Good response reduction was observed up to the 148dB level. The experiment was stopped at 154 dB due to wire breakage from vibration at a transducer wire joint. The PZT transducers, however, were still bonded well on the panel and survived at this high dB level. We also observed shifting of the frequency peaks toward lower frequency when the OASPL

  10. An Investigation of High-Cycle Fatigue Models for Metallic Structures Exhibiting Snap-Through Response

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Rizzi, Stephen A.; Sweitzer, Karl A.

    2007-01-01

    A study is undertaken to develop a methodology for determining the suitability of various high-cycle fatigue models for metallic structures subjected to combined thermal-acoustic loadings. Two features of this problem differentiate it from the fatigue of structures subject to acoustic loading alone. Potentially large mean stresses associated with the thermally pre- and post-buckled states require models capable of handling those conditions. Snap-through motion between multiple post-buckled equilibrium positions introduces very high alternating stress. The thermal-acoustic time history response of a clamped aluminum beam structure with geometric and material nonlinearities is determined via numerical simulation. A cumulative damage model is employed using a rainflow cycle counting scheme and fatigue estimates are made for 2024-T3 aluminum using various non-zero mean fatigue models, including Walker, Morrow, Morrow with true fracture strength, and MMPDS. A baseline zero-mean model is additionally considered. It is shown that for this material, the Walker model produces the most conservative fatigue estimates when the stress response has a tensile mean introduced by geometric nonlinearity, but remains in the linear elastic range. However, when the loading level is sufficiently high to produce plasticity, the response becomes more fully reversed and the baseline, Morrow, and Morrow with true fracture strength models produce the most conservative fatigue estimates.

  11. Bithermal fatigue - A link between isothermal and thermomechanical fatigue

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.; Mcgaw, Michael A.; Bill, Robert C.; Fanti, Paolo D.

    1988-01-01

    A technique for bithermal fatigue testing is presented in which the tensile and compressive halves of the cycle are conducted isothermally at two significantly different temperatures. With reference to experimental results obtained for a nickel-base superalloy, B1900 + Hf, it is shown that bithermal fatigue testing is a simple alternative to thermomechanical fatigue and can provide a conservative determination of thermomechanical fatigue life for creep damage dominated failure modes. Bithermal fatigue results can be directly related to thermomechanical fatigue results through the use of an appropriate damage rule.

  12. NMR logging apparatus

    DOEpatents

    Walsh, David O; Turner, Peter

    2014-05-27

    Technologies including NMR logging apparatus and methods are disclosed. Example NMR logging apparatus may include surface instrumentation and one or more downhole probes configured to fit within an earth borehole. The surface instrumentation may comprise a power amplifier, which may be coupled to the downhole probes via one or more transmission lines, and a controller configured to cause the power amplifier to generate a NMR activating pulse or sequence of pulses. Impedance matching means may be configured to match an output impedance of the power amplifier through a transmission line to a load impedance of a downhole probe. Methods may include deploying the various elements of disclosed NMR logging apparatus and using the apparatus to perform NMR measurements.

  13. Sample positioning apparatus

    DOEpatents

    Bell, Thomas H.; Johnson, Jr., Charles H.; Lane, Robert L.; Martin, Bradley E.; Tyree, William H.

    1976-01-06

    Apparatus for use in alpha particle counting with such as photomultiplier tubes, comprising a platform and linkage mechanism whereby samples are moved in linear manner toward and away from ends of the photomultiplier tubes.

  14. Apparatus for Teaching Physics

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1977-01-01

    Describes apparatus utilized to demonstrate physics principle. Equipment described includes a low pressure chamber, a 360 degree loop ramp, a tilted table demonstrating motion principles, and a method for casting a three dimensional display of magnetic lines of force. (SL)

  15. Apparatus for growing crystals

    NASA Technical Reports Server (NTRS)

    Jasinski, Thomas J. (Inventor); Witt, August F. (Inventor)

    1986-01-01

    An improved apparatus and method for growing crystals from a melt employing a heat pipe, consisting of one or more sections, each section serving to control temperature and thermal gradients in the crystal as it forms inside the pipe.

  16. Battery cell feedthrough apparatus

    DOEpatents

    Kaun, T.D.

    1995-03-14

    A compact, hermetic feedthrough apparatus is described comprising interfitting sleeve portions constructed of chemically-stable materials to permit unique battery designs and increase battery life and performance. 8 figs.

  17. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B.; Carpenter, D. Rae, Jr.

    1984-01-01

    Describes an apparatus for viewing one- and two-dimensional collisions and coupled pendulums on an overhead projector. Suggested demonstrations for the two-dimensional colliding balls and for the two-dimensional coupled pendulums are provided. (JN)

  18. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1982-01-01

    Describes a demonstration to initiate discussion about electrostatic effects. Also describes and evaluates a Magnetic Bubble Apparatus, a device which exhibits several phenomena related to magnetic domain formation. Includes manufacturer's response to the evaluation. (JN)

  19. Gas turbine sealing apparatus

    DOEpatents

    Marra, John Joseph; Wessell, Brian J.; Liang, George

    2013-03-05

    A sealing apparatus in a gas turbine. The sealing apparatus includes a seal housing apparatus coupled to a disc/rotor assembly so as to be rotatable therewith during operation of the gas turbine. The seal housing apparatus comprises a base member, a first leg portion, a second leg portion, and spanning structure. The base member extends generally axially between forward and aft rows of rotatable blades and is positioned adjacent to a row of stationary vanes. The first leg portion extends radially inwardly from the base member and is coupled to the disc/rotor assembly. The second leg portion is axially spaced from the first leg portion, extends radially inwardly from the base member, and is coupled to the disc/rotor assembly. The spanning structure extends between and is rigidly coupled to each of the base member, the first leg portion, and the second leg portion.

  20. An Economical Electrophoresis Apparatus

    ERIC Educational Resources Information Center

    Andrews, I. M.

    1975-01-01

    Describes the production of an electrophoresis apparatus from commonly discarded articles. Outlines paper and gel electrophoresis and its application to the separation of amino acids and intestinal enzymes. (GS)

  1. Acoustic-loads research for powered-lift configurations

    NASA Technical Reports Server (NTRS)

    Schoenster, J. A.; Willis, C. M.; Schroeder, J. C.; Mixson, J. S.

    1976-01-01

    Data presented from large-scale model tests with jet engines having thrusts of 9 kN (2000 lb) and 36 kN (8000 lb) include acoustic loads for an externally blown wing and flap induced by a TF34 jet engine, an upper surface blown (USB) aircraft model in a wind tunnel, and two USB models in static tests. Comparisons of these results with results from acoustic loads studies on configurations of other sizes are made and the implications of these results on interior noise and acoustic fatigue are discussed.

  2. Regularities of Acoustic Emission in the Freight Car Solebar Materials

    NASA Astrophysics Data System (ADS)

    Bekher, S.

    2016-01-01

    Acoustic emission results which were obtained during tests of the samples, which were made from foundry solebars with the developing fatigue crack, are presented. The dependences of the acoustic emission event count, the force critical value during the stationary acoustic emission process, and the growth rate of the event count from the cycles number are determined. The amplitude signal distributions relating to the crack growth were received. It is offered to use the force critical value and the amplitude threshold in the rejection criteria.

  3. Cooperative implementation of a high temperature acoustic sensor

    NASA Astrophysics Data System (ADS)

    Baldini, S. E.; Nowakowski, Edward; Smith, Herbert G.; Friebele, E. J.; Putnam, Martin A.; Rogowski, Robert; Melvin, Leland D.; Claus, Richard O.; Tran, Tuan; Holben, Milford S., Jr.

    1991-12-01

    The current status and results of a cooperative program aimed at the implementation of a high-temperature acoustic/strain sensor onto metallic structures are reported. The sensor systems that are to be implemented under this program will measure thermal expansion, maneuver loads, aircraft buffet, sonic fatigue, and acoustic emissions in environments that approach 1800 F. The discussion covers fiber development, fabrication of an extrinsic Fabry-Perot interferometer acoustic sensor, sensor mounting/integration, and results of an evaluation of the sensor capabilities.

  4. Cooperative implementation of a high temperature acoustic sensor

    NASA Technical Reports Server (NTRS)

    Baldini, S. E.; Nowakowski, Edward; Smith, Herbert G.; Friebele, E. J.; Putnam, Martin A.; Rogowski, Robert; Melvin, Leland D.; Claus, Richard O.; Tran, Tuan; Holben, Milford S., Jr.

    1991-01-01

    The current status and results of a cooperative program aimed at the implementation of a high-temperature acoustic/strain sensor onto metallic structures are reported. The sensor systems that are to be implemented under this program will measure thermal expansion, maneuver loads, aircraft buffet, sonic fatigue, and acoustic emissions in environments that approach 1800 F. The discussion covers fiber development, fabrication of an extrinsic Fabry-Perot interferometer acoustic sensor, sensor mounting/integration, and results of an evaluation of the sensor capabilities.

  5. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, B.T.; Chou, C.H.

    1990-03-20

    A shear acoustic transducer-lens system is described in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens. 9 figs.

  6. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, Butrus T.; Chou, Ching H.

    1990-01-01

    A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.

  7. Materials research at Stanford University. [composite materials, crystal structure, acoustics

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Research activity related to the science of materials is described. The following areas are included: elastic and thermal properties of composite materials, acoustic waves and devices, amorphous materials, crystal structure, synthesis of metal-metal bonds, interactions of solids with solutions, electrochemistry, fatigue damage, superconductivity and molecular physics and phase transition kinetics.

  8. Fiber pulling apparatus modification

    NASA Technical Reports Server (NTRS)

    Smith, Guy A.; Workman, Gary L.

    1992-01-01

    A reduced gravity fiber pulling apparatus (FPA) was constructed in order to study the effects of gravity on glass fiber formation. The apparatus was specifically designed and built for use on NASA's KC-135 aircraft. Four flights have been completed to date during which E-glass fiber was successfully produced in simulated zero, high, and lunar gravity environments. In addition simulated lunar soil samples were tested for their fiber producing properties using the FPA.

  9. Electric arc saw apparatus

    DOEpatents

    Deichelbohrer, P.R.

    1983-08-08

    A portable, hand-held electric arc saw apparatus comprising a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc between the blade and a workpiece of opposite polarity. Electrically conducting means are provided on said frame for transmitting current to said blade. A pair of freely movable endless belts in the form of crawler treads are employed to facilitate movement of the apparatus relative to the workpiece.

  10. CONTINUOUS TREATMENT APPARATUS

    DOEpatents

    Erickson, E.E.

    1962-05-15

    An apparatus is described for dissolving a nuclear reactor fuel element in strong acid solutlon. The vapors and entrained liquid resulting from the violent reaction of dissolution are led into a reflux condenser which discharges, not directly back into the top of the reaction vessel in the conventional manner, but by a route leading to the bottom of the apparatus, thereby utilizing the energy of the reaction to bring about a circulation of the solution. (AEC)

  11. Spin coating apparatus

    DOEpatents

    Torczynski, John R.

    2000-01-01

    A spin coating apparatus requires less cleanroom air flow than prior spin coating apparatus to minimize cleanroom contamination. A shaped exhaust duct from the spin coater maintains process quality while requiring reduced cleanroom air flow. The exhaust duct can decrease in cross section as it extends from the wafer, minimizing eddy formation. The exhaust duct can conform to entrainment streamlines to minimize eddy formation and reduce interprocess contamination at minimal cleanroom air flow rates.

  12. Vacuum pump apparatus

    DOEpatents

    Batzer, Thomas H.; Call, Wayne R.

    1985-01-01

    An improved cryopumping apparatus which comprises a cryopumping space which may be alternately opened and closed from the surrounding area by moveable panels, trubular cryopanels within said cryopumping space through which a coolant such as liquid helium may be passed, and an apparatus for spraying liquid argon onto said cylindrical cryopanels in order to enhance the cryogenic entrapment of such low-z ions, atoms, and molecules as hydrogen and helium.

  13. Infrared microscope inspection apparatus

    DOEpatents

    Forman, Steven E.; Caunt, James W.

    1985-02-26

    Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface.

  14. Infrared microscope inspection apparatus

    DOEpatents

    Forman, S.E.; Caunt, J.W.

    1985-02-26

    Apparatus and system for inspecting infrared transparents, such as an array of photovoltaic modules containing silicon solar cells, includes an infrared microscope, at least three sources of infrared light placed around and having their axes intersect the center of the object field and means for sending the reflected light through the microscope. The apparatus is adapted to be mounted on an X-Y translator positioned adjacent the object surface. 4 figs.

  15. Battery formation charging apparatus

    SciTech Connect

    Stewart, J.L.

    1987-08-04

    An apparatus is describe for charging electric storage batteries, the apparatus comprising: (a) a host computer for providing charging information to and receiving status information from at least one slave computer by means of a data link; and (b) at least one control module coupled to the slave computer for applying charging current to at least one electric storage battery in response to instructions received from the slave computer, and for providing feedback and status information to the slave computer.

  16. Ultrasonic fluid flow measurement method and apparatus

    DOEpatents

    Kronberg, J.W.

    1993-10-12

    An apparatus for measuring the flow of a fluid in a pipe using ultrasonic waves. The apparatus comprises an ultrasonic generator, a lens for focusing the sound energy produced by the generator, and means for directing the focused energy into the side of the pipe through an opening and in a direction close to parallel to the long axis of the pipe. A cone carries the sound energy to the lens from the generator. Depending on the choice of materials, there may be a quarter-wave, acoustic impedance matching section between the generator and the cone to reduce the reflections of energy at the cone boundary. The lens material has an acoustic impedance similar to that of the cone material but a different sonic velocity so that the lens can converge the sound waves in the fluid. A transition section between the lens and the fluid helps to couple the energy to the fluid and assures it is directed as close to parallel to the fluid flow direction as possible. 3 figures.

  17. Ultrasonic fluid flow measurement method and apparatus

    DOEpatents

    Kronberg, James W.

    1993-01-01

    An apparatus for measuring the flow of a fluid in a pipe using ultrasonic waves. The apparatus comprises an ultrasonic generator, a lens for focusing the sound energy produced by the generator, and means for directing the focused energy into the side of the pipe through an opening and in a direction close to parallel to the long axis of the pipe. A cone carries the sound energy to the lens from the generator. Depending on the choice of materials, there may be a quarter-wave, acoustic impedance matching section between the generator and the cone to reduce the reflections of energy at the cone boundary. The lens material has an acoustic impedance similar to that of the cone material but a different sonic velocity so that the lens can converge the sound waves in the fluid. A transition section between the lens and the fluid helps to couple the energy to the fluid and assures it is directed as close to parallel to the fluid flow direction as possible.

  18. Acoustic emission source mechanisms for steel bridge material

    NASA Astrophysics Data System (ADS)

    Hossain, M.; Yu, J.; Ziehl, P.; Caicedo, J.; Matta, F.; Guo, S.; Sutton, M.

    2013-01-01

    Over the past twenty years acoustic emission (AE) has been studied for applications to the structural health monitoring (SHM) of metallic structures. The success of AE for prognosis of in-service steel bridges depends on the reliability of the received AE signals. The emphasis of this paper is on the characterization of acoustic emission source mechanisms for ASTM A572 grade 50 steel. The source characterization was aided by Digital Imaging Correlation (DIC) and Scanning Electronic Microscopy (SEM). The results indicate that both ductile and brittle mechanisms can produce AE during fatigue crack growth in the steel. However, the fracture mechanisms are predominately ductile. A key preliminary finding is that fatigue crack extension does not generally produce AE events in the early stage of fatigue crack growth for the steel bridge material investigated.

  19. Medical Acoustics

    NASA Astrophysics Data System (ADS)

    Beach, Kirk W.; Dunmire, Barbrina

    Medical acoustics can be subdivided into diagnostics and therapy. Diagnostics are further separated into auditory and ultrasonic methods, and both employ low amplitudes. Therapy (excluding medical advice) uses ultrasound for heating, cooking, permeablizing, activating and fracturing tissues and structures within the body, usually at much higher amplitudes than in diagnostics. Because ultrasound is a wave, linear wave physics are generally applicable, but recently nonlinear effects have become more important, even in low-intensity diagnostic applications.

  20. Cavitation controlled acoustic probe for fabric spot cleaning and moisture monitoring

    DOEpatents

    Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, Apostolos C.

    1997-01-01

    A method and apparatus are provided for monitoring a fabric. An acoustic probe generates acoustic waves relative to the fabric. An acoustic sensor, such as an accelerometer is coupled to the acoustic probe for generating a signal representative of cavitation activity in the fabric. The generated cavitation activity representative signal is processed to indicate moisture content of the fabric. A feature of the invention is a feedback control signal is generated responsive to the generated cavitation activity representative signal. The feedback control signal can be used to control the energy level of the generated acoustic waves and to control the application of a cleaning solution to the fabric.

  1. Dependence of Microelastic-plastic Nonlinearity of Martensitic Stainless Steel on Fatigue Damage Accumulation

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.

    2006-01-01

    Self-organized substructural arrangements of dislocations formed in wavy slip metals during cyclic stress-induced fatigue produce substantial changes in the material microelastic-plastic nonlinearity, a quantitative measure of which is the nonlinearity parameter Beta extracted from acoustic harmonic generation measurements. The contributions to Beta from the substructural evolution of dislocations and crack growth for fatigued martensitic 410Cb stainless steel are calculated from the Cantrell model as a function of percent full fatigue life to fracture. A wave interaction factor f(sub WI) is introduced into the model to account experimentally for the relative volume of material fatigue damage included in the volume of material swept out by an interrogating acoustic wave. For cyclic stress-controlled loading at 551 MPa and f(sub WI) = 0.013 the model predicts a monotonic increase in Beta from dislocation substructures of almost 100 percent from the virgin state to roughly 95 percent full life. Negligible contributions from cracks are predicted in this range of fatigue life. However, over the last five percent of fatigue life the model predicts a rapid monotonic increase of Beta by several thousand percent that is dominated by crack growth. The theoretical predictions are in good agreement with experimental measurements of 410Cb stainless steel samples fatigued in uniaxial, stress-controlled cyclic loading at 551 MPa from zero to full tensile load with a measured f(sub WI) of 0.013.

  2. Dependence of microelastic-plastic nonlinearity of martensitic stainless steel on fatigue damage accumulation

    SciTech Connect

    Cantrell, John H.

    2006-09-15

    Self-organized substructural arrangements of dislocations formed during cyclic stress-induced fatigue of metals produce substantial changes in the material microelastic-plastic nonlinearity, a quantitative measure of which is the nonlinearity parameter {beta} extracted from acoustic harmonic generation measurements. The contributions to {beta} from the substructural evolution of dislocations and crack growth for fatigued martensitic 410Cb stainless steel are calculated from the Cantrell model [Proc. R. Soc. London, Ser. A 460, 757 (2004)] as a function of percent full fatigue life to fracture. A wave interaction factor f{sub WI} is introduced into the model to account experimentally for the relative volume of fatigue damage included in the total volume of material swept out by an interrogating acoustic wave. For cyclic stress-controlled loading at 551 MPa and f{sub WI}=0.013 the model predicts a monotonic increase in {beta} from dislocation substructures of almost 100% from the virgin state to roughly 95% full life. Negligible contributions from cracks are predicted in this range of fatigue life. However, during the last 5% of fatigue life the model predicts a rapid monotonic increase of {beta} by several thousand percent that is dominated by crack growth. The theoretical predictions are in good agreement with experimental measurements of 410Cb stainless steel samples fatigued in uniaxial, stress-controlled cyclic loading at 551 MPa from zero to full tensile load with a measured f{sub WI} of 0.013.

  3. Apparatus for measuring a sorbate dispersed in a fluid stream

    NASA Technical Reports Server (NTRS)

    Updike, O. L. (Inventor)

    1977-01-01

    A sensitive, miniature apparatus was designed for measuring low concentrations of a sorbate dispersed in a fluid stream. The device consists of an elongated body having a surface capable of sorbing an amount of the sorbate proportional to the concentration in the fluid stream and propagating acoustic energy along its length. The acoustic energy is converted to an electrical output signal corresponding to the concentration of sorbate in the fluid stream. The device can be designed to exhibit high sensitivity to extremely small amounts of sorbate dispersed in a fluid stream and to exhibit low sensitivity to large amounts of sorbate. Another advantage is that the apparatus may be formed in a microminiature size and at a low cost using bath microfabrication technology.

  4. Apparatus and techniques for measuring bedload

    USGS Publications Warehouse

    Hubbell, David Wellington

    1964-01-01

    The need for accurate determinations of the total sediment discharge of particles of bedload size has prompted this investigation of available and possible measuring apparatus and procedures. The accuracy of measurements of sediment discharge made with trap-type samplers is affected by the variability of sampler efficiency, by the oscillatory variation of bedload discharge, and by sampler placement. Equations that were developed for determining total discharge from measured bedioad discharge and measured suspended-sediment discharge are simplest if the bedload apparatus measures only the true bedload. Early bedload samplers are generally unsatisfactory. Recently developed or suggested apparatus include various improved samplers of the pressure-difference type, a pumping sampler, a magnetic sampler, acoustical instruments that measure the magnitude of the sound of particle collisions, an ultrasonic bedload sampler designed to measure and integrate electronically the concentration and velocity, and a tiltmeter designed to measure the total sediment discharge from the ground tilt that results from the passage of flow. All the pressure-difference samplers are improvements over early samplers, but none are void of the inherent shortcomings of trap-type apparatus; probably the Sphinx (Dutch) and VUV (Hungarian) samplers are the most satisfactory. The acoustical instruments are capable of measuring only the relative discharge. The ultrasonic sampler and the tiltmeter are not adequate without further development. Some new possible apparatus and means for measuring or aiding in measuring bedload discharge are small pit samplers, ultrasonic sounders, pressure transducers, and photography. A small pit sampler for measuring bedload discharge was designed to provide self-placement and portability ; however, its practicability and efficiency are undetermined. Exploratory films show that by using slowmotion photography the discharge of particles larger than about pea size can be

  5. Fatigue: an overview.

    PubMed

    Rosenthal, Thomas C; Majeroni, Barbara A; Pretorius, Richard; Malik, Khalid

    2008-11-15

    Fatigue, a common presenting symptom in primary care, negatively impacts work performance, family life, and social relationships. The differential diagnosis of fatigue includes lifestyle issues, physical conditions, mental disorders, and treatment side effects. Fatigue can be classified as secondary to other medical conditions, physiologic, or chronic. The history and physical examination should focus on identifying common secondary causes (e.g., medications, anemia, pregnancy) and life-threatening problems, such as cancer. Results of laboratory studies affect management in only 5 percent of patients, and if initial results are normal, repeat testing is generally not indicated. Treatment of all types of fatigue should include a structured plan for regular physical activity that consists of stretching and aerobic exercise, such as walking. Caffeine and modafinil may be useful for episodic situations requiring alertness. Short naps are proven performance enhancers. Selective serotonin reuptake inhibitors, such as fluoxetine, paroxetine, or sertraline, may improve energy in patients with depression. Patients with chronic fatigue may respond to cognitive behavior therapy. Scheduling regular follow-up visits, rather than sporadic urgent appointments, is recommended for effective long-term management. PMID:19035066

  6. Fatigue of advanced materials

    SciTech Connect

    Dauskardt, R.H.; Ritchie, R.O. . Center for Advanced Materials); Cox, B.N. )

    1993-08-01

    The development of toughened ceramics over the past 10 to 15 years is arguably one of the most important materials breakthroughs of this century. Monolithic and composite ceramic materials having fracture toughnesses up to an order of magnitude higher than those available 20 years ago have been produced using technologies based on scientific understanding and micromechanical models for in situ phase transformation, fiber bridging, ductile-particle toughening, and other toughening mechanisms. The irony of this, however, is that although ceramics can now be seriously considered for many structural applications, they can also, contrary to popular belief, be susceptible to degradation under cyclic fatigue loading. This is true even when the loading is fully compressive. As a result, a great deal of attention is now being paid to ceramic fatigue, largely because of the importance of cyclic loading in many of the potential applications for ceramics, such as gas-turbine and reciprocating engines. However, because the field is in its infancy, only limited fatigue property data have been documented, understanding of salient fatigue mechanisms has not been achieved, and the design of ceramic microstructures for optimum fatigue resistance has yet to be attempted.

  7. Thermal fatigue of beryllium

    SciTech Connect

    Deksnis, E.; Ciric, D.; Falter, H.

    1995-09-01

    Thermal fatigue life of S65c beryllium castellated to a geometry 6 x 6 x (8-10)mm deep has been tested for steady heat fluxes of 3 MW/m{sup 2} to 5 MW/m{sup 2} and under pulsed heat fluxes (10-20 MW/m{sup 2}) for which the time averaged heat flux is 5 MW/m{sup 2}. These tests were carried out in the JET neutral beam test facility A test sequence with peak surface temperatures {le} 600{degrees}C produced no visible fatigue cracks. In the second series of tests, with T{sub max} {le} 750{degrees}C evidence for fatigue appeared after a minimum of 1350 stress cycles. These fatigue data are discussed in view of the observed lack of thermal fatigue in JET plasma operations with beryllium PFC. JET experience with S65b and S65c is reviewed; recent operations with {Phi} = 25 MW/m{sup 2} and sustained melting/resolidification are also presented. The need for a failure criterion for finite element analyses of Be PFC lifetimes is discussed.

  8. Surface contact fatigue and flexural fatigue of dental restorative materials.

    PubMed

    McCabe, J F; Wang, Y; Braem, M

    2000-06-01

    Antagonistic contact on a dental restoration may produce surface and subsurface stresses leading to fatigue wear as well as to bulk stressing, eventually causing catastrophic failure. It was the aim of the present work to study the outcome of two different approaches to fatigue testing of materials involving either surface contact fatigue or flexural fatigue mechanisms. A range of materials was tested, including conventional glass-ionomers, resin-modified glass-ionomers, poly-acid modified composites, and composites. Materials were prepared and tested using both surface contact and flexural fatigue. The results show that conventional glass-ionomers have the least resistance to fatigue under both regimes while composites have the longest fatigue lives and the highest values of flexural fatigue limit. However, the results also support the fact that catastrophic failure should be investigated separately from surface contact fatigue. Within the group of composite products tested, a hybrid composite material had a significantly greater flexural fatigue limit than a microfilled one, but the latter material had a significantly greater surface contact fatigue life, indicating that wear behavior cannot be predicted from bulk fracture characteristics and vice versa. The process of wear occurs by a combination of a number of fundamental processes, and the contribution fatigue makes will vary according to the environment and nature of the material.

  9. An indentation fatigue strength law

    NASA Astrophysics Data System (ADS)

    Xu, Baoxing; Yonezu, Akio; Chen, Xi

    2010-05-01

    Indentation fatigue, where a cyclic load is applied on the sample via an indenter, emerges as an alternative approach for measuring the fatigue properties of materials. We have carried out indentation fatigue tests on a poly(vinyl chloride) (PVC) bulk material, as well as on TiN and NiP films/coatings deposited on SUS304 steel substrates, and demonstrate that a simple power-law relationship can be established between the indentation load amplitude and number of cycles to failure. Such a law is very similar to the conventional fatigue strength law obtained from uniaxial tests. The agreement between the fatigue stress exponents obtained by uniaxial and indentation fatigue tests suggests the potential applicability of the indentation fatigue technique for extracting the fatigue properties of materials.

  10. Low-cycle thermal fatigue

    NASA Technical Reports Server (NTRS)

    Halford, G. R.

    1986-01-01

    A state-of-the-art review is presented of the field of thermal fatigue. Following a brief historical review, the concept is developed that thermal fatigue can be viewed as processes of unbalanced deformation and cracking. The unbalances refer to dissimilar mechanisms occurring in opposing halves of thermal fatigue loading and unloading cycles. Extensive data summaries are presented and results are interpreted in terms of the unbalanced processes involved. Both crack initiation and crack propagation results are summarized. Testing techniques are reviewed, and considerable discussion is given to a technique for thermal fatigue simulation, known as the bithermal fatigue test. Attention is given to the use of isothermal life prediction methods for the prediction of thermal fatigue lives. Shortcomings of isothermally-based life prediction methods are pointed out. Several examples of analyses and thermal fatigue life predictions of high technology structural components are presented. Finally, numerous dos and don'ts relative to design against thermal fatigue are presented.

  11. Relationship between fatigue and photosensitivity.

    PubMed

    Shigihara, Yoshihito; Tanaka, Masaaki; Watanabe, Yasuyoshi

    2010-01-01

    It is considered that photosensitivity is one of the most important factors to cause video-game epilepsy. Since photosensitivity is thought to cause various signs of hypersensitivity in the central nervous system and hypersensitivity is believed to be related to fatigue, whether fatigue is associated with photosensitivity was determined. The study group consisted of 68 healthy medical students attending Osaka City University Graduate School of Medicine. They completed questionnaires dealing with fatigue (Chalder Fatigue Scale) and photosensitivity. On simple regression analyses, fatigue score was positively associated with photosensitivity score. Similarly, on multiple regression analyses adjusted for age, gender, and sleeping hours, fatigue score was positively associated with photosensitivity score. Fatigue is associated with photosensitivity. Our findings provide new perspectives on fatigue.

  12. Chemical analysis of acoustically levitated drops by Raman spectroscopy.

    PubMed

    Tuckermann, Rudolf; Puskar, Ljiljana; Zavabeti, Mahta; Sekine, Ryo; McNaughton, Don

    2009-07-01

    An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS), is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation. After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid-base reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension. PMID:19418043

  13. Polarization Imaging Apparatus

    NASA Technical Reports Server (NTRS)

    Zou, Yingyin K.; Chen, Qiushui

    2010-01-01

    A polarization imaging apparatus has shown promise as a prototype of instruments for medical imaging with contrast greater than that achievable by use of non-polarized light. The underlying principles of design and operation are derived from observations that light interacts with tissue ultrastructures that affect reflectance, scattering, absorption, and polarization of light. The apparatus utilizes high-speed electro-optical components for generating light properties and acquiring polarization images through aligned polarizers. These components include phase retarders made of OptoCeramic (registered TradeMark) material - a ceramic that has a high electro-optical coefficient. The apparatus includes a computer running a program that implements a novel algorithm for controlling the phase retarders, capturing image data, and computing the Stokes polarization images. Potential applications include imaging of superficial cancers and other skin lesions, early detection of diseased cells, and microscopic analysis of tissues. The high imaging speed of this apparatus could be beneficial for observing live cells or tissues, and could enable rapid identification of moving targets in astronomy and national defense. The apparatus could also be used as an analysis tool in material research and industrial processing.

  14. Acoustic Tooth Cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.

    1984-01-01

    Acoustically-energized water jet aids in plaque breakdown. Acoustic Wand includes acoustic transducer 1/4 wave plate, and tapered cone. Together elements energize solution of water containing mild abrasive injected into mouth to help prevent calculous buildup.

  15. Probabilistic Failure Assessment For Fatigue

    NASA Technical Reports Server (NTRS)

    Moore, Nicholas; Ebbeler, Donald; Newlin, Laura; Sutharshana, Sravan; Creager, Matthew

    1995-01-01

    Probabilistic Failure Assessment for Fatigue (PFAFAT) package of software utilizing probabilistic failure-assessment (PFA) methodology to model high- and low-cycle-fatigue modes of failure of structural components. Consists of nine programs. Three programs perform probabilistic fatigue analysis by means of Monte Carlo simulation. Other six used for generating random processes, characterizing fatigue-life data pertaining to materials, and processing outputs of computational simulations. Written in FORTRAN 77.

  16. Motion measurement of acoustically levitated object

    NASA Technical Reports Server (NTRS)

    Watkins, John L. (Inventor); Barmatz, Martin B. (Inventor)

    1993-01-01

    A system is described for determining motion of an object that is acoustically positioned in a standing wave field in a chamber. Sonic energy in the chamber is sensed, and variation in the amplitude of the sonic energy is detected, which is caused by linear motion, rotational motion, or drop shape oscillation of the object. Apparatus for detecting object motion can include a microphone coupled to the chamber and a low pass filter connected to the output of the microphone, which passes only frequencies below the frequency of sound produced by a transducer that maintains the acoustic standing wave field. Knowledge about object motion can be useful by itself, can be useful to determine surface tension, viscosity, and other information about the object, and can be useful to determine the pressure and other characteristics of the acoustic field.

  17. Application of an ultrasonic focusing radiator for acoustic levitation of submillimeter samples

    NASA Technical Reports Server (NTRS)

    Lee, M. C.

    1981-01-01

    An acoustic apparatus has been specifically developed to handle samples of submillimeter size in a gaseous medium. This apparatus consists of an acoustic levitation device, deployment devices for small liquid and solid samples, heat sources for sample heat treatment, acoustic alignment devices, a cooling system and data-acquisition instrumentation. The levitation device includes a spherical aluminum dish of 12 in. diameter and 0.6 in. thickness, 130 pieces of PZT transducers attached to the back side of the dish and a spherical concave reflector situated in the vicinity of the center of curvature of the dish. The three lowest operating frequencies for the focusing-radiator levitation device are 75, 105 and 163 kHz, respectively. In comparison with other levitation apparatus, it possesses a large radiation pressure and a high lateral positional stability. This apparatus can be used most advantageously in the study of droplets and spherical shell systems, for instance, for fusion target applications.

  18. Application of an ultrasonic focusing radiator for acoustic levitation of submillimeter samples

    SciTech Connect

    Lee, M.C.

    1981-01-01

    An acoustic apparatus has been specifically developed to handle samples of submillimeter size in a gaseous medium. This apparatus consists of an acoustic levitation device, deployment devices for small liquid and solid samples, heat sources for sample heat treatment, acoustic alignment devices, a cooling system and data-acquisition instrumentation. The levitation device includes a spherical aluminum dish of 12'' diameter and 0.6'' thickness, 130 pieces of PZT tranducers attached to the back side of the dish and a spherical concave reflector situated in the vicinity of the center of curvature of the dish. The three lowest operating frequencies for the focusing-radiator levitation device are 75, 105 and 163 kHz, respectively. In comparison with other levitation apparatus, it possesses a large radiation pressure and a high lateral positional stability. This apparatus can be used most advantageously in the study of droplets and spherical shell systems, for instance, for fusion target applications.

  19. Symptomatic fatigue in multiple sclerosis.

    PubMed

    Freal, J E; Kraft, G H; Coryell, J K

    1984-03-01

    Symptomatic fatigue has not been investigated previously in a multiple sclerosis population. Potential subjects were the 78% of 656 individuals with multiple sclerosis who indicated in a previous study that they experienced symptomatic fatigue. Three hundred nine subjects (60%) returned a follow-up questionnaire on symptomatic fatigue. Ninety percent described fatigue as "tiredness or the need to rest," but 43% of them indicated that "sleepiness" was part of the symptomatology. In 48% fatigue made other MS symptoms worse. Fatigue tended to occur in the late afternoon and evening. It occurred almost daily for more than 66% of the subjects. In 47% of the subjects fatigue usually subsided within a few hours; in other subjects occurrences were of variable length (40%) or lasted between 6 and 24 hours (8%). Ninety percent said that fatigue was worse at warmer environmental temperatures. Fatigue was worse for 83% after "vigorous exercise" and for 64% after "moderate exercise" although 15% reported that moderate exercise helped to reduce fatigue. Meditation, some drugs, and cooling with water reduced fatigue in a majority of the small proportion of the population trying these techniques. A planned daily schedule of activity and rest seemed to be a partially effective response to symptomatic fatigue for the majority of subjects studied.

  20. Hydraulic Fatigue-Testing Machine

    NASA Technical Reports Server (NTRS)

    Hodo, James D.; Moore, Dennis R.; Morris, Thomas F.; Tiller, Newton G.

    1987-01-01

    Fatigue-testing machine applies fluctuating tension to number of specimens at same time. When sample breaks, machine continues to test remaining specimens. Series of tensile tests needed to determine fatigue properties of materials performed more rapidly than in conventional fatigue-testing machine.

  1. Biological particle identification apparatus

    DOEpatents

    Salzman, Gary C.; Gregg, Charles T.; Grace, W. Kevin; Hiebert, Richard D.

    1989-01-01

    An apparatus and method for making multiparameter light scattering measurements from suspensions of biological particles is described. Fourteen of the sixteen Mueller matrix elements describing the particles under investigation can be substantially individually determined as a function of scattering angle and probing radiations wavelength, eight elements simultaneously for each of two apparatus configurations using an apparatus which incluees, in its simplest form, two polarization modulators each operating at a chosen frequency, one polarizer, a source of monochromatic electromagnetic radiation, a detector sensitive to the wavelength of radiation employed, eight phase-sensitive detectors, and appropriate electronics. A database of known biological particle suspensions can be assembled, and unknown samples can be quickly identified once measurements are performed on it according to the teachings of the subject invention, and a comparison is made with the database.

  2. Passive orientation apparatus

    DOEpatents

    Spletzer, Barry L.; Fischer, Gary J.; Martinez, Michael A.

    2001-01-01

    An apparatus that can return a payload to a known orientation after unknown motion, without requiring external power or complex mechanical systems. The apparatus comprises a faceted cage that causes the system to rest in a stable position and orientation after arbitrary motion. A gimbal is mounted with the faceted cage and holds the payload, allowing the payload to move relative to the stable faceted cage. The payload is thereby placed in a known orientation by the interaction of gravity with the geometry of the faceted cage, the mass of the system, and the motion of the payload and gimbal. No additional energy, control, or mechanical actuation is required. The apparatus is suitable for use in applications requiring positioning of a payload to a known orientation after arbitrary or uncontrolled motion, including remote sensing and mobile robot applications.

  3. Robot arm apparatus

    DOEpatents

    Nachbar, Henry D.

    1992-01-01

    A robot arm apparatus is provided for inspecting and/or maintaining an interior of a steam generator which has an outside wall and a port for accessing the interior of the steam generator. The robot arm apparatus includes a flexible movable conduit for conveying inspection and/or maintenance apparatus from outside the steam generator to the interior of the steam generator. The flexible conduit has a terminal working end which is translated into and around the interior of the steam generator. Three motors located outside the steam generator are employed for moving the terminal working end inside the steam generator in "x", "y", and "z" directions, respectively. Commonly conducted inspection and maintenance operations include visual inspection for damaged areas, water jet lancing for cleaning sludge deposits, core boring for obtaining sludge deposits, and scrubbing of internal parts.

  4. Robot arm apparatus

    DOEpatents

    Nachbar, Henry D.

    1992-12-01

    A robot arm apparatus is provided for inspecting and/or maintaining an interior of a steam generator which has an outside wall and a port for accessing the interior of the steam generator. The robot arm apparatus includes a flexible movable conduit for conveying inspection and/or maintenance apparatus from outside the steam generator to the interior of the steam generator. The flexible conduit has a terminal working end which is translated into and around the interior of the steam generator. Three motors located outside the steam generator are employed for moving the terminal working end inside the steam generator in "x", "y", and "z" directions, respectively. Commonly conducted inspection and maintenance operations include visual inspection for damaged areas, water jet lancing for cleaning sludge deposits, core boring for obtaining sludge deposits, and scrubbing of internal parts.

  5. Apparatus for fixing latency

    DOEpatents

    Hall, David R.; Bartholomew, David B.; Moon, Justin; Koehler, Roger O.

    2009-09-08

    An apparatus for fixing computational latency within a deterministic region on a network comprises a network interface modem, a high priority module and at least one deterministic peripheral device. The network interface modem is in communication with the network. The high priority module is in communication with the network interface modem. The at least one deterministic peripheral device is connected to the high priority module. The high priority module comprises a packet assembler/disassembler, and hardware for performing at least one operation. Also disclosed is an apparatus for executing at least one instruction on a downhole device within a deterministic region, the apparatus comprising a control device, a downhole network, and a downhole device. The control device is near the surface of a downhole tool string. The downhole network is integrated into the tool string. The downhole device is in communication with the downhole network.

  6. Apparatus for processing coal

    SciTech Connect

    Williams, R.M.

    1985-02-12

    Apparatus for processing coal to prevent the creation of extreme fines and to extract pyrites from the principal coal fractions in which there are two air circulating circuits having processing components which cooperate in their respective circuits to result initially in substantial extraction of fines in the first circuit while releasing principal granulated coal fractions and pyrites to the second circuit where specific gravity separation of the pyrites and principal coal fractions occur. The apparatus includes a source of drying heat added to the air moving in the circuits and delivered at the places where surface moisture drying is most effective. Furthermore, the apparatus is operated so as to reduce coal to a desired size without creating an excessive volume of extreme fines, to separate pyrites and hard to grind components by specific gravity in a region where fines are not present, and to use the extreme fines as a source of fuel to generate drying heat.

  7. Thermal energy test apparatus

    NASA Astrophysics Data System (ADS)

    Audet, N. F.

    1991-10-01

    The Navy Clothing and Textile Research Facility (NCTRF) designed and fabricated a thermal energy test apparatus to permit evaluation of the heat protection provided by crash crew firefighter's proximity clothing materials against radiant and convective heat loads, similar to those found outside the flame zone of aircraft fuel fires. The apparatus employs electrically operated quartz lamp radiant heaters and a hot air convective heater assembly to produce the heat load conditions the materials to be subjected to, and is equipped with heat flux sensors of different sensitivities to measure the incident heat flux on the sample material as well as the heat flux transmitted by the sample. Tests of the apparatus have shown that it can produce radiant heat flux levels equivalent to those estimated to be possible in close proximity to large aircraft fuel fires, and can produce convective heat fluxes equivalent to those measured in close proximity to aircraft fuel fires at upwind and sidewind locations. Work was performed in 1974.

  8. Large Area Nondestructive Evaluation of a Fatigue Loaded Composite Structure

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Burke, Eric R.; Horne, Michael R.; Madaras, Eric I.

    2016-01-01

    Large area nondestructive evaluation (NDE) inspections are required for fatigue testing of composite structures to track damage initiation and growth. Of particular interest is the progression of damage leading to ultimate failure to validate damage progression models. In this work, passive thermography and acoustic emission NDE were used to track damage growth up to failure of a composite three-stringer panel. Fourteen acoustic emission sensors were placed on the composite panel. The signals from the array were acquired simultaneously and allowed for acoustic emission location. In addition, real time thermal data of the composite structure were acquired during loading. Details are presented on the mapping of the acoustic emission locations directly onto the thermal imagery to confirm areas of damage growth leading to ultimate failure. This required synchronizing the acoustic emission and thermal data with the applied loading. In addition, processing of the thermal imagery which included contrast enhancement, removal of optical barrel distortion and correction of angular rotation before mapping the acoustic event locations are discussed.

  9. Expendable oceanographic sensor apparatus

    DOEpatents

    McCoy, Kim O.; Downing, Jr., John P.; DeRoos, Bradley G.; Riches, Michael R.

    1993-01-01

    An expendable oceanographic sensor apparatus is deployed from an airplane or a ship to make oceanographic observations in a profile of the surface-to-ocean floor, while deployed on the floor, and then a second profile when returning to the ocean surface. The device then records surface conditions until on-board batteries fail. All data collected is stored and then transmitted from the surface to either a satellite or other receiving station. The apparatus is provided with an anchor that causes descent to the ocean floor and then permits ascent when the anchor is released. Anchor release is predetermined by the occurrence of a pre-programmed event.

  10. Current measurement apparatus

    DOEpatents

    Umans, Stephen D.

    2008-11-11

    Apparatus and methods are provided for a system for measurement of a current in a conductor such that the conductor current may be momentarily directed to a current measurement element in order to maintain proper current without significantly increasing an amount of power dissipation attributable to the current measurement element or adding resistance to assist in current measurement. The apparatus and methods described herein are useful in superconducting circuits where it is necessary to monitor current carried by the superconducting elements while minimizing the effects of power dissipation attributable to the current measurement element.

  11. Electroplating method and apparatus

    DOEpatents

    Looney, Robert B.; Smith, William E. L.

    1978-06-20

    An apparatus for high speed electroplating or anodizing tubular members such as nuclear reactor fuel elements. A loading arm positions the member on a base for subsequent support by one of two sets of electrical contacts. A carriage assembly positions electrodes into and around the member. Electrolyte is pumped between the electrodes and the member while electric current is applied. Programmed controls sequentially employ each of the two sets of contacts to expose all surfaces of the member to the electrolyte. The member is removed from the apparatus by an unloading arm.

  12. Ultrasonic drilling apparatus

    DOEpatents

    Duran, E.L.; Lundin, R.L.

    1988-06-20

    Apparatus attachable to an ultrasonic drilling machine for drilling deep holes in very hard materials, such as boron carbide, is provided. The apparatus utilizes a hollow spindle attached to the output horn of the ultrasonic drilling machine. The spindle has a hollow drill bit attached at the opposite end. A housing surrounds the spindle, forming a cavity for holding slurry. In operation, slurry is provided into the housing, and into the spindle through inlets while the spindle is rotating and ultrasonically reciprocating. Slurry flows through the spindle and through the hollow drill bit to cleanse the cutting edge of the bit during a drilling operation. 3 figs.

  13. Ultrasonic drilling apparatus

    DOEpatents

    Duran, Edward L.; Lundin, Ralph L.

    1989-01-01

    Apparatus attachable to an ultrasonic drilling machine for drilling deep holes in very hard materials, such as boron carbide, is provided. The apparatus utilizes a hollow spindle attached to the output horn of the ultrasonic drilling machine. The spindle has a hollow drill bit attached at the opposite end. A housing surrounds the spindle, forming a cavity for holding slurry. In operation, slurry is provided into the housing, and into the spindle through inlets while the spindle is rotating and ultrasonically reciprocating. Slurry flows through the spindle and through the hollow drill bit to cleanse the cutting edge of the bit during a drilling operation.

  14. Fissile solution measurement apparatus

    DOEpatents

    Crane, T.W.; Collinsworth, P.R.

    1984-06-11

    An apparatus for determining the content of a fissile material within a solution by detecting delayed fission neutrons emitted by the fissile material after it is temporarily irradiated by a neutron source. The apparatus comprises a container holding the solution and having a portion defining a neutron source cavity centrally disposed within the container. The neutron source cavity temporarily receives the neutron source. The container has portions defining a plurality of neutron detector ports that form an annular pattern and surround the neutron source cavity. A plurality of neutron detectors count delayed fission neutrons emitted by the fissile material. Each neutron detector is located in a separate one of the neutron detector ports.

  15. Visual examination apparatus

    NASA Technical Reports Server (NTRS)

    Haines, R. F.; Fitzgerald, J. W.; Rositano, S. A. (Inventor)

    1973-01-01

    An automated visual examination apparatus for measuring visual sensitivity and mapping blind spot location is described. The apparatus includes a projection system for displaying to a patient a series of visual stimuli, a response switch enabling him to indicate his reaction to the stimuli, and a recording system responsive to both the visual stimuli per se and the patient's response. The recording system provides a correlated permanent record of both stimuli and response from which a substantive and readily apparent visual evaluation can be made.

  16. Microelectromechanical ratcheting apparatus

    DOEpatents

    Barnes, Stephen M.; Miller, Samuel L.; Jensen, Brian D.; Rodgers, M. Steven; Burg, Michael S.

    2001-01-01

    A microelectromechanical (MEM) ratcheting apparatus is disclosed which includes an electrostatic or thermal actuator that drives a moveable member in the form of a ring gear, stage, or rack. Motion is effected by one or more reciprocating pawls driven by the actuator in a direction that is parallel to, in line with, or tangential to the path. The reciprocating pawls engage indexing elements (e.g. teeth or pins) on the moveable member to incrementally move the member along a curved or straight path with the ability to precisely control and determine the position of the moveable member. The MEM apparatus can be formed on a silicon substrate by conventional surface micromachining methods.

  17. Fatigue and thermal fatigue of Pb-Sn solder joints

    SciTech Connect

    Frear, D.; Grivas, D.; McCormack, M.; Tribula, D.; Morris, J.W. Jr.

    1987-01-01

    This paper presents a fundamental investigation of the fatigue and thermal fatigue characteristics, with an emphasis on the microstructural development during fatigue, of Sn-Pb solder joints. Fatigue tests were performed in simple shear on both 60Sn-40Pb and 5Sn-95Pb solder joints. Isothermal fatigue tests show increasing fatigue life of 60Sn-40Pb solder joints with decreasing strain and temperature. In contrast, such behavior was not observed in the isothermal fatigue of 5Sn-95Pb solder joints. Thermal fatigue results on 60Sn-40Pb solder cycled between -55/sup 0/C and 125/sup 0/C show that a coarsened region develops in the center of the joint. Both Pb-rich and Sn-rich phases coarsen, and cracks form within these coarsened regions. The failure mode 60Sn-40Pb solder joints in thermal and isothermal fatigue is similar: cracks form intergranularly through the Sn-rich phase or along Sn/Pb interphase boundaries. Extensive cracking is found throughout the 5Sn-95Pb joint for both thermal and isothermal fatigue. In thermal fatigue the 5Sn-95Pb solder joints failed after fewer cycles than 60Sn-40Pb.

  18. Directional Electrostatic Accretion Process Employing Acoustic Droplet Formation

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard (Inventor)

    1998-01-01

    The present invention is directed to an apparatus for manufacturing a free standing solid metal part. In the present invention, metal droplets are ejected in a nozzleless fashion from a free surface pool of molten metal by applying focused acoustic radiation pressure. The acoustic radiation pressure is produced by high intensity acoustic tone bursts emitted from an acoustic source positioned at the bottom of the pool which directs the acoustic energy at the pool surface. The metal droplets are electrostatically charged so their trajectory can be controlled by electric fields that guide the droplets to predetermined points on a target. The droplets impinge upon the target and solidify with the target material. The accretion of the electrostatically directed solidified droplets forms the free standing metal part.

  19. Method and apparatus for in-process sensing of manufacturing quality

    DOEpatents

    Hartman, Daniel A.; Dave, Vivek R.; Cola, Mark J.; Carpenter, Robert W.

    2005-02-22

    A method for determining the quality of an examined weld joint comprising the steps of providing acoustical data from the examined weld joint, and performing a neural network operation on the acoustical data determine the quality of the examined weld joint produced by a friction weld process. The neural network may be trained by the steps of providing acoustical data and observable data from at least one test weld joint, and training the neural network based on the acoustical data and observable data to form a trained neural network so that the trained neural network is capable of determining the quality of a examined weld joint based on acoustical data from the examined weld joint. In addition, an apparatus having a housing, acoustical sensors mounted therein, and means for mounting the housing on a friction weld device so that the acoustical sensors do not contact the weld joint. The apparatus may sample the acoustical data necessary for the neural network to determine the quality of a weld joint.

  20. Method and Apparatus for In-Process Sensing of Manufacturing Quality

    SciTech Connect

    Hartman, D.A.; Dave, V.R.; Cola, M.J.; Carpenter, R.W.

    2005-02-22

    A method for determining the quality of an examined weld joint comprising the steps of providing acoustical data from the examined weld joint, and performing a neural network operation on the acoustical data determine the quality of the examined weld joint produced by a friction weld process. The neural network may be trained by the steps of providing acoustical data and observable data from at least one test weld joint, and training the neural network based on the acoustical data and observable data to form a trained neural network so that the trained neural network is capable of determining the quality of a examined weld joint based on acoustical data from the examined weld joint. In addition, an apparatus having a housing, acoustical sensors mounted therein, and means for mounting the housing on a friction weld device so that the acoustical sensors do not contact the weld joint. The apparatus may sample the acoustical data necessary for the neural network to determine the quality of a weld joint.

  1. Acoustic transducer

    DOEpatents

    Drumheller, D.S.

    1997-12-30

    An acoustic transducer is described comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2,000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers. 4 figs.

  2. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    1997-01-01

    An acoustic transducer comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers.

  3. Containerless high temperature calorimeter apparatus

    NASA Technical Reports Server (NTRS)

    Lacy, L. L.; Nisen, D. B. (Inventor)

    1981-01-01

    A calorimeter apparatus for measuring high temperature thermophysical properties of materials is disclosed which includes a containerless heating apparatus in which the specimen is suspended and heated by electron bombardment.

  4. Muscle Deoxygenation Causes Muscle Fatigue

    NASA Technical Reports Server (NTRS)

    Murthy, G.; Hargens, A. R.; Lehman, S.; Rempel, D.

    1999-01-01

    Muscle fatigue is a common musculoskeletal disorder in the work place, and may be a harbinger for more disabling cumulative trauma disorders. Although the cause of fatigue is multifactorial, reduced blood flow and muscle oxygenation may be the primary factor in causing muscle fatigue during low intensity muscle exertion. Muscle fatigue is defined as a reduction in muscle force production, and also occurs among astronauts who are subjected to postural constraints while performing lengthy, repetitive tasks. The objectives of this research are to: 1) develop an objective tool to study the role of decreased muscle oxygenation on muscle force production, and 2) to evaluate muscle fatigue during prolonged glovebox work.

  5. Incompatibility and Mental Fatigue

    ERIC Educational Resources Information Center

    Herzog, Thomas R.; Hayes, Lauren J.; Applin, Rebecca C.; Weatherly, Anna M.

    2011-01-01

    A straightforward prediction from attention restoration theory is that the level of incompatibility in a person's life should be positively correlated with that person's level of mental (or directed attention) fatigue. The authors tested this prediction by developing a new self-report measure of incompatibility in which they attempted to isolate…

  6. FATIGUE OF DENTAL CERAMICS

    PubMed Central

    Zhang, Yu; Sailer, Irena; Lawn, Brian R

    2013-01-01

    Objectives Clinical data on survival rates reveal that all-ceramic dental prostheses are susceptible to fracture from repetitive occlusal loading. The objective of this review is to examine the underlying mechanisms of fatigue in current and future dental ceramics. Data/sources The nature of various fatigue modes is elucidated using fracture test data on ceramic layer specimens from the dental and biomechanics literature. Conclusions Failure modes can change over a lifetime, depending on restoration geometry, loading conditions and material properties. Modes that operate in single-cycle loading may be dominated by alternative modes in multi-cycle loading. While post-mortem examination of failed prostheses can determine the sources of certain fractures, the evolution of these fractures en route to failure remains poorly understood. Whereas it is commonly held that loss of load-bearing capacity of dental ceramics in repetitive loading is attributable to chemically-assisted 'slow crack growth' in the presence of water, we demonstrate the existence of more deleterious fatigue mechanisms, mechanical rather than chemical in nature. Neglecting to account for mechanical fatigue can lead to gross overestimates in predicted survival rates. Clinical significance Strategies for prolonging the clinical lifetimes of ceramic restorations are proposed based on a crack-containment philosophy. PMID:24135295

  7. Fatigue of insect cuticle.

    PubMed

    Dirks, Jan-Henning; Parle, Eoin; Taylor, David

    2013-05-15

    Many parts of the insect exoskeleton experience repeated cyclic loading. Although the cuticle of insects and other arthropods is the second most common natural composite material in the world, so far nothing is known about its fatigue properties, despite the fact that fatigue undoubtedly limits the durability of body parts in vivo. For the first time, we here present experimental fatigue data of insect cuticle. Using force-controlled cyclic loading, we determined the number of cycles to failure for hind legs (tibiae) and hind wings of the locust Schistocerca gregaria, as a function of the applied cyclic stress. Our results show that, although both are made from cuticle, these two body parts behave very differently. Wing samples showed a large fatigue range, failing after 100,000 cycles when we applied 46% of the stress needed for instantaneous failure [the ultimate tensile strength (UTS)]. Legs, in contrast, were able to sustain a stress of 76% of the UTS for the same number of cycles to failure. This can be explained by the difference in the composition and structure of the material, two factors that, amongst others, also affect the well-known behaviour of engineering composites. Final failure of the tibiae occurred via one of two different failure modes--propagation in tension or buckling in compression--indicating that the tibia is 'optimized' by evolution to resist both failure modes equally. These results are further discussed in relation to the evolution and normal use of these two body parts.

  8. Fatigue resistance of duralumin

    NASA Technical Reports Server (NTRS)

    1922-01-01

    Where, in the following report, mention is made of fatigue, it always refers to the weakening of the material produced by rapidly changing stresses below the point of elasticity. The alternating stress was obtained by a test bar which was held at one end and subjected to rotation. Most of the tests were conducted on connecting rods.

  9. Physiological Acoustics

    NASA Astrophysics Data System (ADS)

    Young, Eric D.

    The analysis of physiological sound in the peripheral auditory system solves three important problems. First, sound energy impinging on the head must be captured and presented to the transduction apparatus in the ear as a suitable mechanical signal; second, this mechanical signal needs to be transduced into a neural representation that can be used by the brain; third, the resulting neural representation needs to be analyzed by central neurons to extract information useful to the animal. This chapter provides an overview of some aspects of the first two of these processes. The description is entirely focused on the mammalian auditory system, primarily on human hearing and on the hearing of a few commonly used laboratory animals (mainly rodents and carnivores). Useful summaries of non-mammalian hearing are available [1]. Because of the large size of the literature, review papers are referenced wherever possible.

  10. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1980-01-01

    This section presents new ideas with regard to apparatus for teaching physics. The following four ideas are presented: (1) measuring speed of light (2) a poor man's barometer, (3) center of mass of a rotating object, and (4) minimizing glass breakage. (HM)

  11. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B.; Carpenter, D. Rae, Jr.

    1985-01-01

    Describes: (1) the construction of a variable-volume resonator and Raleigh-disk resonance detector from simple materials; and (2) a learning aid for performing 60 experiments in basic electricity and electronics (consisting of a circuit board, components, and mask sheets). Illustrative experiments are included for both apparatus. (DH)

  12. Holographic Animation Apparatus.

    ERIC Educational Resources Information Center

    Johnston, Sean F.

    1979-01-01

    Describes a simple apparatus for producing strip holograms with a number of slit-shaped exposures displaced along the vertical direction. The hologram maintains full horizontal parallax, but the slit aperture reduces the vertical viewing angle of the animated object. (Author/GA)

  13. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1978-01-01

    Describes some laboratory apparatus and demonstrations; describes an electronic device to illustrate an octave synthesizer; shows how to get negative changes from an electrophorous; explains a body levers device to clarify the principles of moments and levers; and finally shows how to demonstrate acceleration in simple harmonic motion. (GA)

  14. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B., Ed.; Carpenter, D. Rae, Jr., Ed.

    1984-01-01

    Describes a "no-cost" apparatus designed to demonstrate rotational inertia. Also describes and evaluates a microprocessor-based instrument (Versatile Laboratory Aid) that performs a large variety of timing and data acquisition tasks encountered in introductory and advanced physics laboratories. (JN)

  15. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B.; Carpenter, D. Rae, Jr.

    1983-01-01

    Describes a coriolis simulator which uses a carbon paper trace technique and a simple specific-heat apparatus, emphasizing instructional considerations. Also indicates that a variac and an ordinary electric drill can be used to wind coil if a lathe or coil winder are unavailable. (JN)

  16. Borehole data transmission apparatus

    DOEpatents

    Kotlyar, O.M.

    1993-03-23

    A borehole data transmission apparatus is described whereby a centrifugal pump impeller(s) is used to provide a turbine stage having substantial pressure characteristics in response to changing rotational speed of a shaft for the pressure pulsing of data from the borehole through the drilling mud to the surface of the earth.

  17. Borehole data transmission apparatus

    DOEpatents

    Kotlyar, Oleg M.

    1993-01-01

    A borehole data transmission apparatus whereby a centrifugal pump impeller(s) is used to provide a turbine stage having substantial pressure characteristics in response to changing rotational speed of a shaft for the pressure pulsing of data from the borehole through the drilling mud to the surface of the earth.

  18. Positioning and locking apparatus

    DOEpatents

    Hayward, Milton L.; Harper, William H.

    1987-01-01

    A positioning and locking apparatus including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member.

  19. Positioning and locking apparatus

    DOEpatents

    Hayward, M.L.; Harper, W.H.

    1987-06-30

    A positioning and locking apparatus are disclosed including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member. 6 figs.

  20. Well pumping apparatus

    SciTech Connect

    Meyer, E.D.

    1981-12-15

    A pumping apparatus that may be used with a well in which a sucker rod is connected with the well so as to remain in axial alignment with the same during shifting of the well and the sucker rod is supported clear of the well and the structure for operating the same.

  1. Mobile lighting apparatus

    DOEpatents

    Roe, George Michael; Klebanoff, Leonard Elliott; Rea, Gerald W; Drake, Robert A; Johnson, Terry A; Wingert, Steven John; Damberger, Thomas A; Skradski, Thomas J; Radley, Christopher James; Oros, James M; Schuttinger, Paul G; Grupp, David J; Prey, Stephen Carl

    2013-05-14

    A mobile lighting apparatus includes a portable frame such as a moveable trailer or skid having a light tower thereon. The light tower is moveable from a stowed position to a deployed position. A hydrogen-powered fuel cell is located on the portable frame to provide electrical power to an array of the energy efficient lights located on the light tower.

  2. NUCLEAR CONVERSION APPARATUS

    DOEpatents

    Seaborg, G.T.

    1960-09-13

    A nuclear conversion apparatus is described which comprises a body of neutron moderator, tubes extending therethrough, uranium in the tubes, a fluid- circulating system associated with the tubes, a thorium-containing fluid coolant in the system and tubes, and means for withdrawing the fluid from the system and replacing it in the system whereby thorium conversion products may be recovered.

  3. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B.; Carpenter, D. Rae, Jr.

    1984-01-01

    Describes an apparatus which demonstrates the stability of equilibrium of multidimensional objects and helps students to understand the concept of a lever arm. Also describes an alternative to the standard black, mercury "student cell" used as a reference voltage for calibrating a slide-wire potentiometer. (JN)

  4. Pump apparatus including deconsolidator

    SciTech Connect

    Sonwane, Chandrashekhar; Saunders, Timothy; Fitzsimmons, Mark Andrew

    2014-10-07

    A pump apparatus includes a particulate pump that defines a passage that extends from an inlet to an outlet. A duct is in flow communication with the outlet. The duct includes a deconsolidator configured to fragment particle agglomerates received from the passage.

  5. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B.; Carpenter, D. Rae, Jr.

    1984-01-01

    Discusses a low-cost apparatus for measuring moment of inertia utilizing an interval timer, induction coil, battery eliminator, and ball bearing mounted disk. Also provides a method for demonstrating vectors using a cardboard box and a piece of string. (JM)

  6. Multipurpose binocular scanning apparatus

    NASA Technical Reports Server (NTRS)

    Chamberlain, F. R.; Parker, G. L.

    1969-01-01

    Optical gimballing apparatus directs narrow fields of view throughout solid angle approaching 4 pi steradians. Image rotation produced by scanning can be eliminated or altered by gear trains directly linked to the scanning drive assembly. It provides the basis for a binocular scanning capability.

  7. Micromachine friction test apparatus

    DOEpatents

    deBoer, Maarten P.; Redmond, James M.; Michalske, Terry A.

    2002-01-01

    A microelectromechanical (MEM) friction test apparatus is disclosed for determining static or dynamic friction in MEM devices. The friction test apparatus, formed by surface micromachining, is based on a friction pad supported at one end of a cantilevered beam, with the friction pad overlying a contact pad formed on the substrate. A first electrostatic actuator can be used to bring a lower surface of the friction pad into contact with an upper surface of the contact pad with a controlled and adjustable force of contact. A second electrostatic actuator can then be used to bend the cantilevered beam, thereby shortening its length and generating a relative motion between the two contacting surfaces. The displacement of the cantilevered beam can be measured optically and used to determine the static or dynamic friction, including frictional losses and the coefficient of friction between the surfaces. The test apparatus can also be used to assess the reliability of rubbing surfaces in MEM devices by producing and measuring wear of those surfaces. Finally, the friction test apparatus, which is small in size, can be used as an in situ process quality tool for improving the fabrication of MEM devices.

  8. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1980-01-01

    Presents two experimental set-ups. The first demonstrates the law of Malus using a pair of Polaroid polarizers and a monochromatic light source with an interference filter. The second describes a modification of Hilton's apparatus to demonstrate the effects of the magnetic hysteresis on an overhead projector. (CS)

  9. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Connolly, Walter, Ed.

    1990-01-01

    Provides the apparatus setup, experimental method, necessary formulas, and references for three measurement experiments: (1) "Determine the Magnetic Induction of a Coil with a Hall Element"; (2) "Measuring Magnetic Force and Magnetic Field of Small Permanent Magnets"; and (3) "Measurements of Sound Velocity by Means of PZT" (piezoelectric…

  10. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B.; Carpenter, D. Rae, Jr.

    1985-01-01

    Explains: (1) use of piezoelectric film (connected to power supply and oscilloscope) to reveal force-versus-time curves of bouncing balls; (2) use of bound wood splints or meter sticks to illustrate tree or tower stability; and (3) apparatus of co-axial discs with connected linking rods and suspended bobs to simulate waves. (DH)

  11. Autonomous data transmission apparatus

    DOEpatents

    Kotlyar, Oleg M.

    1997-01-01

    A autonomous borehole data transmission apparatus for transmitting measurement data from measuring instruments at the downhole end of a drill string by generating pressure pulses utilizing a transducer longitudinally responsive to magnetic field pulses caused by electrical pulses corresponding to the measured downhole parameters.

  12. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1979-01-01

    Six different pieces of physics apparatus are described: Telsa Coil for instant ignition of sodium arc lamps, Timekube, Magnetic Maps of the United States, a slinky with vertical mounting, a wave generator power supply, and a long-period timer power switch. Price and supplier are included. (BT)

  13. Apparatus for Teaching Physics

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H.

    1977-01-01

    Describes: how to measure index of refraction by the thickness method; how to teach the concept of torque using a torque wrench; how to produce a real image with a concave mirror; how to eliminate the interface effects of a Pyrex containers; and an apparatus to illustrate Bernoulli's Principle. (MLH)

  14. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Mamola, Karl C., Ed.

    1993-01-01

    Discusses how to build an inexpensive Young's modulus apparatus and also a lens with an adjustable focal length. Describes the demonstration of moving a peeled, hard-boiled egg in and out of a flask whose neck is slightly smaller than the egg. (MVL)

  15. Pruning apparatus and method

    DOEpatents

    Dellinger, Roger D.

    1997-01-01

    The present invention is an automated pruning apparatus that requires little or no follow-up hand pruning and requires no sensors to avoid supportive trunks or posts. The present invention uses at least one pair of flat, close angled toothed, counter rotating blades. Woody branches are directed to the counter rotating blades first with a lifting arm and secondly by a quilled drum.

  16. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1978-01-01

    Describes a few apparatuses and demonstrations for teaching physics under the headings: demonstrating resonance of the inner ear, constructing a potential well-hill for overhead projectors, rubber tube vacuum pump, improvement on the simple homemade motor, air track to demonstrate sailing into the wind, and center of gravity and stability. (GA)

  17. Autonomous data transmission apparatus

    DOEpatents

    Kotlyar, O.M.

    1997-03-25

    A autonomous borehole data transmission apparatus is described for transmitting measurement data from measuring instruments at the downhole end of a drill string by generating pressure pulses utilizing a transducer longitudinally responsive to magnetic field pulses caused by electrical pulses corresponding to the measured downhole parameters. 4 figs.

  18. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Gottlieb, Herbert H., Ed.

    1981-01-01

    Describes an apparatus for plotting electric fields using burglar alarm window tape for electrodes and carbonized electronic stencil paper as sheet resistance. Also describes a simple pentode modulator circuit which will modulate a typical helium-neon gas laser, providing an audio channel for demonstration purposes. (SK)

  19. Apparatus for obstacle traversion

    DOEpatents

    Borenstein, Johann

    2004-08-10

    An apparatus for traversing obstacles having an elongated, round, flexible body that includes a plurality of drive track assemblies. The plurality of drive track assemblies cooperate to provide forward propulsion wherever a propulsion member is in contact with any feature of the environment, regardless of how many or which ones of the plurality of drive track assemblies make contact with such environmental feature.

  20. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B.; Carpenter, D. Rae

    1985-01-01

    Describes these tools for physics teaching: (1) stick with calibrations for measuring student reaction time; (2) compact high-pressure sodium lamps used to demonstrate spectra; (3) air pumps for fish tanks providing simple inexpensive motors; (4) a rotating manometer for measuring centripetal force; and (5) an apparatus for checking conservation…

  1. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B., Ed.; Carpenter, D. Rae, Jr., Ed.

    1983-01-01

    Standing transverse waves in homogeneous strings have been demonstrated in lectures and used in experiments (called Melde's experiment). A variation to this experiment is discussed. Also discusses the use of the speed-of-sound resonance-tube apparatus to clean mercury. (Author/JN)

  2. Apparatus for Teaching Physics.

    ERIC Educational Resources Information Center

    Minnix, Richard B., Ed.; Carpenter, D. Rae, Jr., Ed.

    1983-01-01

    Describes four body-lever models (biceps, triceps, back lever when lifting, foot lever and Achilles tendon muscle) used in noncalculus physics courses. Instructions for constructing the wooden models are provided. Also describes an improvement on a centripetal-force apparatus so that it is easier to operate. (JN)

  3. Positioning and locking apparatus

    DOEpatents

    Hayward, M.L.; Harper, W.H.

    1985-06-19

    A positioning and locking apparatus including a fixture having a rotatable torque ring provided with a plurality of cam segments for automatically guiding a container into a desired location within the fixture. Rotation of the ring turns the container into a final position in pressure sealing relation against a hatch member.

  4. Dynamic response analysis of an aircraft structure under thermal-acoustic loads

    NASA Astrophysics Data System (ADS)

    Cheng, H.; Li, H. B.; Zhang, W.; Wu, Z. Q.; Liu, B. R.

    2016-09-01

    Future hypersonic aircraft will be exposed to extreme combined environments includes large magnitude thermal and acoustic loads. It presents a significant challenge for the integrity of these vehicles. Thermal-acoustic test is used to test structures for dynamic response and sonic fatigue due to combined loads. In this research, the numerical simulation process for the thermal acoustic test is presented, and the effects of thermal loads on vibro-acoustic response are investigated. To simulate the radiation heating system, Monte Carlo theory and thermal network theory was used to calculate the temperature distribution. Considering the thermal stress, the high temperature modal parameters are obtained with structural finite element methods. Based on acoustic finite element, modal-based vibro-acoustic analysis is carried out to compute structural responses. These researches are very vital to optimum thermal-acoustic test and structure designs for future hypersonic vehicles structure

  5. Radioactive waste processing apparatus

    DOEpatents

    Nelson, R.E.; Ziegler, A.A.; Serino, D.F.; Basnar, P.J.

    1985-08-30

    Apparatus for use in processing radioactive waste materials for shipment and storage in solid form in a container is disclosed. The container includes a top, and an opening in the top which is smaller than the outer circumference of the container. The apparatus includes an enclosure into which the container is placed, solution feed apparatus for adding a solution containing radioactive waste materials into the container through the container opening, and at least one rotatable blade for blending the solution with a fixing agent such as cement or the like as the solution is added into the container. The blade is constructed so that it can pass through the opening in the top of the container. The rotational axis of the blade is displaced from the center of the blade so that after the blade passes through the opening, the blade and container can be adjusted so that one edge of the blade is adjacent the cylindrical wall of the container, to insure thorough mixing. When the blade is inside the container, a substantially sealed chamber is formed to contain vapors created by the chemical action of the waste solution and fixant, and vapors emanating through the opening in the container. The chamber may be formed by placing a removable extension over the top of the container. The extension communicates with the apparatus so that such vapors are contained within the container, extension and solution feed apparatus. A portion of the chamber includes coolant which condenses the vapors. The resulting condensate is returned to the container by the force of gravity.

  6. Acoustic emission descriptors

    NASA Astrophysics Data System (ADS)

    Witos, Franciszek; Malecki, Ignacy

    The authors present selected problems associated with acoustic emission interpreted as a physical phenomenon and as a measurement technique. The authors examine point sources of acoustic emission in isotropic, homogeneous linearly elastic media of different shapes. In the case of an unbounded medium the authors give the analytical form of the stress field and the wave shift field of the acoustic emission. In the case of a medium which is unbounded plate the authors give a form for the equations which is suitable for numerical calculation of the changes over time of selected acoustic emission values. For acoustic emission as a measurement technique, the authors represent the output signal as the resultant of a mechanical input value which describes the source, the transient function of the medium, and the transient function of specific components of the measurement loop. As an effect of this notation, the authors introduce the distinction between an acoustic measurement signal and an acoustic measurement impulse. The authors define the basic parameters of an arbitrary impulse. The authors extensively discuss the signal functions of acoustic emission impulses and acoustic emission signals defined in this article as acoustic emission descriptors (or signal functions of acoustic emission impulses) and advanced acoustic emission descriptors (which are either descriptors associated with acoustic emission applications or the signal functions of acoustic emission signals). The article also contains the results of experimental research on three different problems in which acoustic emission descriptors associated with acoustic emission pulses, acoustic emission applications, and acoustic emission signals are used. These problems are respectively: a problem of the amplitude-load characteristics of acoustic emission pulses in carbon samples subjected to compound uniaxial compression, the use of acoustic emission to predict the durability characteristics of conveyor belts, and

  7. Modeling nonlinearities of ultrasonic waves for fatigue damage characterization: theory, simulation, and experimental validation.

    PubMed

    Hong, Ming; Su, Zhongqing; Wang, Qiang; Cheng, Li; Qing, Xinlin

    2014-03-01

    A dedicated modeling technique for comprehending nonlinear characteristics of ultrasonic waves traversing in a fatigued medium was developed, based on a retrofitted constitutive relation of the medium by considering the nonlinearities originated from material, fatigue damage, as well as the "breathing" motion of fatigue cracks. Piezoelectric wafers, for exciting and acquiring ultrasonic waves, were integrated in the model. The extracted nonlinearities were calibrated by virtue of an acoustic nonlinearity parameter. The modeling technique was validated experimentally, and the results showed satisfactory consistency in between, both revealing: the developed modeling approach is able to faithfully simulate fatigue crack-incurred nonlinearities manifested in ultrasonic waves; a cumulative growth of the acoustic nonlinearity parameter with increasing wave propagation distance exists; such a parameter acquired via a sensing path is nonlinearly related to the offset distance from the fatigue crack to that sensing path; and neither the incidence angle of the probing wave nor the length of the sensing path impacts on the parameter significantly. This study has yielded a quantitative characterization strategy for fatigue cracks using embeddable piezoelectric sensor networks, facilitating deployment of structural health monitoring which is capable of identifying small-scale damage at an embryo stage and surveilling its growth continuously.

  8. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  9. Acoustic cryocooler

    DOEpatents

    Swift, Gregory W.; Martin, Richard A.; Radenbaugh, Ray

    1990-01-01

    An acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube. Thermoacoustic elements in the TAD are spaced apart a distance effective to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15-60 Hz. At these low operating frequencies, a long tube is required to support the standing wave. The tube may be coiled to reduce the overall length of the cryocooler. One or two PTR's are located on the standing wave tube adjacent antinodes in the standing wave to be driven by the standing wave pressure oscillations. It is predicted that a heat input of 1000 W at 1000 K will maintian a cooling load of 5 W at 80 K.

  10. Different types of fatigue in patients with facioscapulohumeral dystrophy, myotonic dystrophy and HMSN-I. Experienced fatigue and physiological fatigue.

    PubMed

    Kalkman, Joke S; Zwarts, Machiel J; Schillings, Maartje L; van Engelen, Baziel G M; Bleijenberg, Gijs

    2008-09-01

    Although fatigue is a common symptom in neuromuscular disorders, little is known about different types of fatigue. Sixty-five FSHD, 79 adult-onset MD and 73 HMSN type I patients were studied. Experienced fatigue was assessed with the CIS-fatigue subscale. Physiological fatigue was measured during a 2-min sustained maximal voluntary contraction of the biceps brachii muscle using the twitch interpolation technique to assess central activation failure (CAF) and peripheral fatigue. Experienced fatigue, CAF and peripheral fatigue appeared to be predominantly separate types of fatigue. PMID:18690504

  11. Titanium honeycomb acoustic lining structural and thermal test report. [for acoustic tailpipe for JT8D engine

    NASA Technical Reports Server (NTRS)

    Joynes, D.; Balut, J. P.

    1974-01-01

    The results are presented of static, fatigue and thermal testing of titanium honeycomb acoustic panels representing the acoustic tailpipe for the Pratt and Whitney Aircraft JT8D Refan engine which is being studied for use on the Boeing 727-200 airplane. Test specimens represented the engine and tailpipe flange joints, the rail to which the thrust reverser is attached and shear specimens of the tailpipe honeycomb. Specimens were made in four different batches with variations in configuration, materials and processes in each. Static strength of all test specimens exceeded the design ultimate load requirements. Fatigue test results confirmed that aluminum brazed titanium, as used in the Refan tailpipe design, meets the fatigue durability objectives. Quality of welding was found to be critical to life, with substandard welding failing prematurely, whereas welding within the process specification exceeded the panel skin life. Initial fatigue testing used short grip length bolts which failed prematurely. These were replaced with longer bolts and subsequent testing demonstrated the required life. Thermal tests indicate that perforated skin acoustic honeycomb has approximately twice the heat transfer of solid skin honeycomb.

  12. Acoustic telemetry.

    SciTech Connect

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

    Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.

  13. High Speed Research Program Structural Acoustics Multi-Year Summary Report

    NASA Technical Reports Server (NTRS)

    Beier, Theodor H.; Bhat, Waman V.; Rizzi, Stephen A.; Silcox, Richard J.; Simpson, Myles A.

    2005-01-01

    This report summarizes the work conducted by the Structural Acoustics Integrated Technology Development (ITD) Team under NASA's High Speed Research (HSR) Phase II program from 1993 to 1999. It is intended to serve as a reference for future researchers by documenting the results of the interior noise and sonic fatigue technology development activities conducted during this period. For interior noise, these activities included excitation modeling, structural acoustic response modeling, development of passive treatments and active controls, and prediction of interior noise. For sonic fatigue, these activities included loads prediction, materials characterization, sonic fatigue code development, development of response reduction techniques, and generation of sonic fatigue design requirements. Also included are lessons learned and recommendations for future work.

  14. Chronic fatigue and chronic fatigue syndrome: shifting boundaries and attributions.

    PubMed

    Lloyd, A R

    1998-09-28

    The subjective symptom of "fatigue" is one of the most widespread in the general population and is a major source of healthcare utilization. Prolonged fatigue is often associated with neuropsychological and musculoskeletal symptoms that form the basis of several syndromal diagnoses including chronic fatigue syndrome, fibromyalgia, and neurasthenia, and is clearly not simply the result of a lack of force generation from the muscle. Current epidemiologic research in this area relies predominantly on self-report data to document the prevalence and associations of chronic fatigue. Of necessity, this subjective data source gives rise to uncertain diagnostic boundaries and consequent divergent epidemiologic, clinical, and pathophysiologic research findings. This review will highlight the impact of the case definition and ascertainment methods on the varying prevalence estimates of chronic fatigue syndrome and patterns of reported psychological comorbidty. It will also evaluate the evidence for a true postinfective fatigue syndrome.

  15. Dual excitation acoustic paramagnetic logging tool

    DOEpatents

    Vail, III, William B.

    1989-01-01

    New methods and apparatus are disclosed which allow measurement of the presence of oil and water in gelogical formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleous present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be preformed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described.

  16. Dual excitation acoustic paramagnetic logging tool

    DOEpatents

    Vail, W.B. III.

    1989-02-14

    New methods and apparatus are disclosed which allow measurement of the presence of oil and water in geological formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleons present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be performed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described. 6 figs.

  17. [Childhood chronic fatigue syndrome].

    PubMed

    Miike, Teruhisa

    2007-06-01

    Chronic fatigue syndrome in childhood and adolescents(CCFS) is a complex and debilitation with severe morbidity and confusion. It is common condition with up to 3-5% of children and adolescents showing strange fatigue and confusion for more than 30 days. In this condition, four major symptoms are important: sleep disorders, easy fatigability, disturbed learning and memorization and immunological problems. Routine laboratory studies are similar to adult CFS, although abnormalities can be seen on serum pyruvic acid level, OGTT pattern, deep body temperature rhythm, hormonal secretion rhythm, and cerebral blood flow. For a diagnosis of CCFS, a research group supported by Japanese ministry of health, labor and welfare developed CCFS case definition on 2004. Treatment focused to correct disrupted circadian rhythms and supply of energy.

  18. Probabilistic Mesomechanical Fatigue Model

    NASA Technical Reports Server (NTRS)

    Tryon, Robert G.

    1997-01-01

    A probabilistic mesomechanical fatigue life model is proposed to link the microstructural material heterogeneities to the statistical scatter in the macrostructural response. The macrostructure is modeled as an ensemble of microelements. Cracks nucleation within the microelements and grow from the microelements to final fracture. Variations of the microelement properties are defined using statistical parameters. A micromechanical slip band decohesion model is used to determine the crack nucleation life and size. A crack tip opening displacement model is used to determine the small crack growth life and size. Paris law is used to determine the long crack growth life. The models are combined in a Monte Carlo simulation to determine the statistical distribution of total fatigue life for the macrostructure. The modeled response is compared to trends in experimental observations from the literature.

  19. Nonlinear acoustics experimental characterization of microstructure evolution in Inconel 617

    SciTech Connect

    Yao, Xiaochu; Liu, Yang; Lissenden, Cliff J.

    2014-02-18

    Inconel 617 is a candidate material for the intermediate heat exchanger in a very high temperature reactor for the next generation nuclear power plant. This application will require the material to withstand fatigue-ratcheting interaction at temperatures up to 950°C. Therefore nondestructive evaluation and structural health monitoring are important capabilities. Acoustic nonlinearity (which is quantified in terms of a material parameter, the acoustic nonlinearity parameter, β) has been proven to be sensitive to microstructural changes in material. This research develops a robust experimental procedure to track the evolution of damage precursors in laboratory tested Inconel 617 specimens using ultrasonic bulk waves. The results from the acoustic non-linear tests are compared with stereoscope surface damage results. Therefore, the relationship between acoustic nonlinearity and microstructural evaluation can be clearly demonstrated for the specimens tested.

  20. Planar oscillatory stirring apparatus

    NASA Technical Reports Server (NTRS)

    Wolf, M. F. (Inventor)

    1985-01-01

    The present invention is directed to an apparatus for stirring materials using planar orthogonal axes oscillations. The apparatus has a movable slide plate sandwiched between two fixed parallel support plates. Pressurized air is supplied to the movable slide plate which employs a tri-arm air bearing vent structure which allows the slide plate to float and to translate between the parallel support plates. The container having a material to be stirred is secured to the upper surface of the slide plate through an aperture in the upper support plate. A motor driven eccentric shaft loosely extends into a center hole bearing of the slide plate to cause the horizontal oscillations. Novelty lies in the combination of elements which exploits the discovery that low frequency, orthogonal oscillations applied horizontally to a Bridgman crucible provides a very rigorous stirring action, comparable with and more effective by an order of magnitude than the accelerated crucible rotation technique.

  1. Thermal protection apparatus

    DOEpatents

    Bennett, Gloria A.; Moore, Troy K.

    1988-01-01

    An apparatus for thermally protecting heat sensitive components of tools. The apparatus comprises a Dewar for holding the heat sensitive components. The Dewar has spaced-apart inside and outside walls, an open top end and a bottom end. An insulating plug is located in the top end. The inside wall has portions defining an inside wall aperture located at the bottom of the Dewar and the outside wall has portions defining an outside wall aperture located at the bottom of the Dewar. A bottom connector has inside and outside components. The inside component sealably engages the inside wall aperture and the outside component sealably engages the outside wall aperture. The inside component is operatively connected to the heat sensitive components and to the outside component. The connections can be made with optical fibers or with electrically conducting wires.

  2. Microscope collision protection apparatus

    DOEpatents

    DeNure, Charles R.

    2001-10-23

    A microscope collision protection apparatus for a remote control microscope which protects the optical and associated components from damage in the event of an uncontrolled collision with a specimen, regardless of the specimen size or shape. In a preferred embodiment, the apparatus includes a counterbalanced slide for mounting the microscope's optical components. This slide replaces the rigid mounts on conventional upright microscopes with a precision ball bearing slide. As the specimen contacts an optical component, the contacting force will move the slide and the optical components mounted thereon. This movement will protect the optical and associated components from damage as the movement causes a limit switch to be actuated, thereby stopping all motors responsible for the collision.

  3. Gas shielding apparatus

    DOEpatents

    Brandt, D.

    1985-12-31

    An apparatus is disclosed for preventing oxidation by uniformly distributing inert shielding gas over the weld area of workpieces such as pipes being welded together. The apparatus comprises a chamber and a gas introduction element. The chamber has an annular top wall, an annular bottom wall, an inner side wall and an outer side wall connecting the top and bottom walls. One side wall is a screen and the other has a portion defining an orifice. The gas introduction element has a portion which encloses the orifice and can be one or more pipes. The gas introduction element is in fluid communication with the chamber and introduces inert shielding gas into the chamber. The inert gas leaves the chamber through the screen side wall and is dispersed evenly over the weld area. 3 figs.

  4. Energy conversion apparatus

    SciTech Connect

    Fuchs, F.J.

    1982-04-20

    An apparatus for maintaining the speed of rotation of a windmill rotor at a fixed ratio to the free flow velocity of the driving wind. This arrangement permits the windmill rotor to rotate at the speed at which its power output is maximized. The apparatus includes a plurality of interleaved rotating and stationary friction discs which convert the rotational kinetic energy of the windmill rotor shaft into thermal energy. An anemometer shaft, which rotates with a velocity which is proportional to the ambient wind velocity, drives a gear train which increases or decreases the pressure on the friction discs so that the load on the rotor is increased or decreased, in an offsetting manner, as the wind velocity changes.

  5. Fast shutter apparatus

    DOEpatents

    Zimmermann, Eugene L.; Kania, Don R.

    1985-01-01

    An apparatus for protecting diagnostic equipment from blast damage by rapidly interposing a shutter between the equipment and the blast area. The apparatus comprises a sensor for sensing a trigger signal associated with the blast and for converting it into a voltage pulse. The voltage pulse is received by the first end of a firing pin. A pressure chamber holds a gas under pressure. The second end of the firing pin is located inside the pressure chamber and is located above a foil member covering an orifice. When the voltage pulse reaches the second end, a point-to-plane discharge ruptures the foil, allowing the gas to enter a drive housing and quickly move a drive piston away from the foil. A drive rod connects the drive piston to a shutter and as the drive piston is moved down, the shutter moves into a closed position, protecting the equipment from debris.

  6. Fast shutter apparatus

    DOEpatents

    Zimmermann, E.L.; Kania, D.R.

    1984-06-27

    An apparatus for protecting diagnostic equipment from blast damage by rapidly interposing a shutter between the equipment and the blast area. The apparatus comprises a sensor for sensing a trigger signal associated with the blast and for converting it into a voltage pulse. The voltage pulse is received by the first end of a firing pin. A pressure chamber holds a gas under pressure. The second end of the firing pin is located inside the pressure chamber and is located above a foil member covering an orifice. When the voltage pulse reaches the second end, a point-to-plane discharge ruptures the foil, allowing the gas to enter a drive housing and quickly move a drive piston away from the foil. A drive rod connects the drive piston to a shutter and as the drive piston is moved down, the shutter moves into a closed position, protecting the equipment from debris.

  7. Wet atmospheric generation apparatus

    NASA Technical Reports Server (NTRS)

    Hamner, Richard M. (Inventor); Allen, Janice K. (Inventor)

    1990-01-01

    The invention described relates to an apparatus for providing a selectively humidified gas to a camera canister containing cameras and film used in space. A source of pressurized gas (leak test gas or motive gas) is selected by a valve, regulated to a desired pressure by a regulator, and routed through an ejector (venturi device). A regulated source of water vapor in the form of steam from a heated reservoir is coupled to a low pressure region of the ejector which mixes with high velocity gas flow through the ejector. This mixture is sampled by a dew point sensor to obtain dew point thereof (ratio of water vapor to gas) and the apparatus adjusted by varying gas pressure or water vapor to provide a mixture at a connector having selected humidity content.

  8. Portable shower apparatus

    NASA Technical Reports Server (NTRS)

    Grenier, Francis E. (Inventor)

    1993-01-01

    A multipurpose, collapsible, shower apparatus for use almost anywhere but especially adapted for use in places somewhat remote from civilization such as recreational vehicles, campers, the outdoors, space vehicles and the like where there may be a limited amount of water or other liquid. The collapsible shower apparatus includes a curtain assembly having an inner wall, an outer wall and a porous element for separating the inner and outer walls; a series of spaced hollow hoops connected by one or more sets of hollow tubes (manifolds); one or more nozzles connected to and in communication with at least one of the hollow hoops; a source of fluid under pressure in communication with at least one of the hollow hoops; and a suction pump for withdrawing fluid from the interior of the curtain assembly.

  9. Electrocell method and apparatus

    SciTech Connect

    Mensink, D.L.; Graham, F.R.; Younkins, R.M.

    1990-01-01

    This invention consists of an apparatus including an electrocell and, preferably, also a diaphragm pump for processing waste materials and recovering metals therefrom. The electrocell comprises a set of coaxial cylinders with end housings to maintain spacing. The innermost cylinder is a cathode. Surrounding the cathode is a porous barrier, then an anode and finally an outer shell. Interior to the cathode is a cathode coolant passage. Between the cathode and the porous barrier is a passage for a catholyte. Between the porous barrier and the anode is a passage for an anolyte. Exterior to the anode but inside an outer shell is a passage for the anode coolant. The passage for the anolyte is dimensioned, based upon the flow rate of the anolyte, to produce fully turbulent flow, preferably with a Reynolds number in excess of 4000. The diaphragm pump surges anolyte into the anolyte passage to further increase turbulence, thereby increasing the efficiency of the apparatus.

  10. Electrocell method and apparatus

    SciTech Connect

    Mensink, D.L.; Graham, F.R.; Younkins, R.M.

    1990-12-31

    This invention consists of an apparatus including an electrocell and, preferably, also a diaphragm pump for processing waste materials and recovering metals therefrom. The electrocell comprises a set of coaxial cylinders with end housings to maintain spacing. The innermost cylinder is a cathode. Surrounding the cathode is a porous barrier, then an anode and finally an outer shell. Interior to the cathode is a cathode coolant passage. Between the cathode and the porous barrier is a passage for a catholyte. Between the porous barrier and the anode is a passage for an anolyte. Exterior to the anode but inside an outer shell is a passage for the anode coolant. The passage for the anolyte is dimensioned, based upon the flow rate of the anolyte, to produce fully turbulent flow, preferably with a Reynolds number in excess of 4000. The diaphragm pump surges anolyte into the anolyte passage to further increase turbulence, thereby increasing the efficiency of the apparatus.

  11. Electrowinning apparatus and process

    SciTech Connect

    Buschmann, Wayne E.

    2012-06-19

    Apparatus and processes are disclosed for electrowinning metal from a fluid stream. A representative apparatus comprises at least one spouted bed reactor wherein each said reactor includes an anolyte chamber comprising an anode and configured for containing an anolyte, a catholyte chamber comprising a current collector and configured for containing a particulate cathode bed and a flowing stream of an electrically conductive metal-containing fluid, and a membrane separating said anolyte chamber and said catholyte chamber, an inlet for an electrically conductive metal-containing fluid stream; and a particle bed churning device configured for spouting particle bed particles in the catholyte chamber independently of the flow of said metal-containing fluid stream. In operation, reduced heavy metals or their oxides are recovered from the cathode particles.

  12. Gas shielding apparatus

    DOEpatents

    Brandt, Daniel

    1985-01-01

    An apparatus for preventing oxidation by uniformly distributing inert shielding gas over the weld area of workpieces such as pipes being welded together. The apparatus comprises a chamber and a gas introduction element. The chamber has an annular top wall, an annular bottom wall, an inner side wall and an outer side wall connecting the top and bottom walls. One side wall is a screen and the other has a portion defining an orifice. The gas introduction element has a portion which encloses the orifice and can be one or more pipes. The gas introduction element is in fluid communication with the chamber and introduces inert shielding gas into the chamber. The inert gas leaves the chamber through the screen side wall and is dispersed evenly over the weld area.

  13. Pressure pulse detection apparatus

    SciTech Connect

    Claycomb, J.R.

    1981-04-14

    A pressure pulse detection apparatus is disclosed which is adapted to receive small signals from downhole measuring while drilling apparatus which signals are propogated as pressure pulses traveling upstream in a column of drilling mud, which signals are obscured by mud pump pressure and velocity variations traveling downstream and which are significantly larger. The preferred embodiment incorporates a transient pressure transducer and an ultrasonic fluid velocity detector, the two forming output signals which are conditioned, amplified and offset against one another. They cancel (When properly calibrated) so that pressure and velocity variations from the mud pump upstream are nulled to zero. They reinforce so that pressure and velocity variations from the downhole signal generator are enhanced, thereby forming an output signal of downhole variations of interest.

  14. Gas turbine sealing apparatus

    SciTech Connect

    Wiebe, David J; Wessell, Brian J; Ebert, Todd; Beeck, Alexander; Liang, George; Marussich, Walter H

    2013-02-19

    A gas turbine includes forward and aft rows of rotatable blades, a row of stationary vanes between the forward and aft rows of rotatable blades, an annular intermediate disc, and a seal housing apparatus. The forward and aft rows of rotatable blades are coupled to respective first and second portions of a disc/rotor assembly. The annular intermediate disc is coupled to the disc/rotor assembly so as to be rotatable with the disc/rotor assembly during operation of the gas turbine. The annular intermediate disc includes a forward side coupled to the first portion of the disc/rotor assembly and an aft side coupled to the second portion of the disc/rotor assembly. The seal housing apparatus is coupled to the annular intermediate disc so as to be rotatable with the annular intermediate disc and the disc/rotor assembly during operation of the gas turbine.

  15. Effects of surface integrity on the fatigue life of thin flexing membranes.

    PubMed

    Sinnott, M M; Hoeppner, D W; Romney, E; Dew, P A

    1989-01-01

    It has been known for some time that surface integrity has an effect on the fatigue life of metals and "brittle" polymers. In cardiovascular applications of polymeric materials, emphasis is placed on elastomers having extended flexure lifetimes (i.e., fatigue life). The effect of surface integrity on the performance properties of Biomer (Ethicon, Inc, Somerville, NJ) a segmented polyurethane used in many blood contacting devices, is being investigated using uniaxial tensile tests in air at room temperature, and biaxial fatigue tests in deionized water at body temperature. Tensile tests were done using ASTM-D-882: Standard Test Methods for Tensile Properties of Thin Plastic Sheeting. No significant differences were noted in the stress-strain curves for specimens with various surface finishes. Fatigue tests were performed using an apparatus developed to allow for the exposure of thin-sheet polymer specimens to fluid at body temperature, while being biaxially strained. Because no standard test method was available, a test protocol was developed with reference to ASTM-D-671-78: Standard Test Methods for the Flexural Fatigue of Plastics by Constant Amplitude of Force. Stress versus life cycle data for specimens with differing surface finishes are being collected. Results to date suggest fatigue life of thin flexing membranes will decrease with increasing order of surface roughness, and fatigue properties are more sensitive to effects of changes in surface integrity than tensile properties measured by monotonic loading.

  16. Fatigue syndrome in sarcoidosis.

    PubMed

    Górski, Witold; Piotrowski, Wojciech J

    2016-01-01

    Sarcoidosis is an inflammatory disease of unknown etiology. Most commonly it results in the formation of non-caseating granulomas in intrathoracic lymph nodes and lung parenchyma, but the clinical course and picture may be complicated by extrapulmonary involvement and many non-respiratory signs and symptoms which are directly related to the disease. In addition, sarcoidosis patients may suffer from a plethora of symptoms of uncertain or unknown origin. Fatigue is one of these symptoms, and according to some authors it is reported by the majority of patients with active sarcoidosis, but also by a smaller proportion of patients with inactive sarcoidosis, or even with complete clinical and radiological remission. Therefore the term fatigue syndrome is frequently used to name this clinical problem. The definition of fatigue syndrome in sarcoidosis is imprecise and the syndrome is usually recognized by use of validated questionnaires. In this review the uptodate knowledge in this field was presented and different challenges connected with this syndrome were described.

  17. ISOTOPE SEPARATING APPARATUS CONTROL

    DOEpatents

    Barnes, S.W.

    1959-08-25

    An improved isotope separating apparatus of the electromagnetic type, commonly referred to as a calutron, is described. Improvements in detecting and maintaining optimum position and focus of the ion beam are given. The calutron collector is provided with an additional electrode insulated from and positioned between the collecting pockets. The ion beams are properly positioned and focused until the deionizing current which flows from ground to this additional electrode ts a minimum.

  18. Demand illumination control apparatus

    NASA Technical Reports Server (NTRS)

    Warren, Carl (Inventor); Arline, Jimmie (Inventor); LaPalme, Julius (Inventor)

    1981-01-01

    Solar illuminating compensating apparatus is disclosed whereby the interior of a building is illuminated to a substantially constant, predetermined level of light intensity by a combination of natural illumination from the sun and artificial illumination from electricity wherein the intensity of said artificial illumination is controlled by fully electronic means which increases the level of artificial illumination when the natural illumination is inadequate and vice versa.

  19. Visual examination apparatus

    NASA Technical Reports Server (NTRS)

    Haines, R. F.; Fitzgerald, J. W.; Rositano, S. A. (Inventor)

    1976-01-01

    An automated visual examination apparatus for measuring visual sensitivity and mapping blind spot location including a projection system for displaying to a patient a series of visual stimuli. A response switch enables him to indicate his reaction to the stimuli, and a recording system responsive to both the visual stimuli per se and the patient's response. The recording system thereby provides a correlated permanent record of both stimuli and response from which a substantive and readily apparent visual evaluation can be made.

  20. Apparatus for photographing meteors

    NASA Technical Reports Server (NTRS)

    Harvey, G. A. (Inventor)

    1973-01-01

    Apparatus for photographing meteors in a selected area of the sky is described. A photomultiplier is pointed in the direction of the area. When a meteor passes through the area the signal output of the photomultiplier increases. Means are provided that activate a camera, pointed at the area, in response to an increased signal from the photomultiplier. Hence, the camera photographs the selected are only while meteors are likely to be passing through the area.

  1. Apparatus for treating wastewater

    SciTech Connect

    Baker, W.E.

    1981-06-09

    Apparatus for treating wastewater includes a settling tank, a sludge digester and a holding tank. Solids from the settling tank are delivered uniformly throughout the seed sludge in the digester and combustible gas is drawn off the top. Sludge from the digester is delivered to the holding tank where further combustible gas evolves and is removed for other uses. The sludge from the holding tank is recycled through the digester or discharged from the system for drying and/or subsequent use.

  2. Lunar deep drill apparatus

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Proposed as a baseline configuration, this rotary drill apparatus is designed to produce 100-mm diameter holes in the lunar surface at depths up to 50 meters. The drill is intended to acquire samples for scientific analysis, mineral resource location, calibration of electronic exploration devices, and foundation analysis at construction sites. It is also intended to prepare holes for emplacement of scientific instruments, the setting of structural anchors, and explosive methods in excavation and mining activities. Defined as a deep drill because of the modular drill string, it incorporates an automatic rod changer. The apparatus is teleoperated from a remote location, such as earth, utilizing supervisory control techniques. It is thus suitable for unmanned and man-tended operation. Proven terrestrial drilling technology is used to the extent it is compatible with the lunar environment. Augers and drive tubes form holes in the regolith and may be used to acquire loose samples. An inertial cutting removal system operates intermittently while rock core drilling is in progress. The apparatus is carried to the work site by a three-legged mobile platform which also provides a 2-meter feed along the hole centerline, an off-hole movement of approximately .5 meters, an angular alignment of up to 20 deg. from gravity vertical, and other dexterity required in handling rods and samples. The technology can also be applied using other carriers which incorporate similar motion capabilities. The apparatus also includes storage racks for augers, rods, and ancillary devices such as the foot-plate that holds the down-hole tooling during rod changing operations.

  3. Micro coring apparatus

    NASA Technical Reports Server (NTRS)

    Collins, David; Brooks, Marshall; Chen, Paul; Dwelle, Paul; Fischer, Ben

    1989-01-01

    A micro-coring apparatus for lunar exploration applications, that is compatible with the other components of the Walking Mobile Platform, was designed. The primary purpose of core sampling is to gain an understanding of the geological composition and properties of the prescribed environment. This procedure has been used extensively for Earth studies and in limited applications during lunar explorations. The corer is described and analyzed for effectiveness.

  4. Heat exchange apparatus

    DOEpatents

    Degtiarenko, Pavel V.

    2003-08-12

    A heat exchange apparatus comprising a coolant conduit or heat sink having attached to its surface a first radial array of spaced-apart parallel plate fins or needles and a second radial array of spaced-apart parallel plate fins or needles thermally coupled to a body to be cooled and meshed with, but not contacting the first radial array of spaced-apart parallel plate fins or needles.

  5. Polarized internal target apparatus

    DOEpatents

    Holt, Roy J.

    1986-01-01

    A polarized internal target apparatus with a polarized gas target of improved polarization and density achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms.

  6. Polarized internal target apparatus

    DOEpatents

    Holt, R.J.

    1984-10-10

    A polarized internal target apparatus with a polarized gas target of improved polarization and density (achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms) is described.

  7. Hollow cathode apparatus

    NASA Technical Reports Server (NTRS)

    Aston, G. (Inventor)

    1984-01-01

    A hollow cathode apparatus is described, which can be rapidly and reliably started. An ignitor positioned upstream from the hollow cathode, generates a puff of plasma that flows with the primary gas to be ionized through the cathode. The plasma puff creates a high voltage breakdown between the downstream end of the cathode and a keeper electrode, to heat the cathode to an electron-emitting temperature.

  8. Apparatus Circulates Sterilizing Gas

    NASA Technical Reports Server (NTRS)

    Cross, John H.; Schwarz, Ray P.

    1991-01-01

    Apparatus circulates sterilizing gas containing ethylene oxide and chlorofluorocarbon through laboratory or medical equipment. Confines sterilizing gas, circulating it only through parts to be treated. Consists of two units. One delivers ethylene oxide/chlorofluorocarbon gas mixture and removes gas after treatment. Other warms, humidifies, and circulates gas through equipment to be treated. Process provides reliable sterilization with negligible residual toxicity from ethylene oxide. Particularly suitable for sterilization of interiors of bioreactors, heart/lung machines, dialyzers, or other equipment including complicated tubing.

  9. Pyrolysis process and apparatus

    DOEpatents

    Lee, Chang-Kuei

    1983-01-01

    This invention discloses a process and apparatus for pyrolyzing particulate coal by heating with a particulate solid heating media in a transport reactor. The invention tends to dampen fluctuations in the flow of heating media upstream of the pyrolysis zone, and by so doing forms a substantially continuous and substantially uniform annular column of heating media flowing downwardly along the inside diameter of the reactor. The invention is particularly useful for bituminous or agglomerative type coals.

  10. Fire suppressing apparatus

    DOEpatents

    Buttrey, Kenneth E.

    1982-11-02

    Apparatus for smothering a liquid sodium fire comprises a pan, a perforated cover on the pan, and tubes depending from the cover and providing communication between the interior of the pan and the ambient atmosphere through the perforations in the cover. Liquid caught in the pan rises above the lower ends of the tubes and thus serves as a barrier which limits the amount of air entering the pan.

  11. Portable cutting apparatus

    DOEpatents

    Gilmore, R.F.

    1984-07-17

    A remotely operable, portable cutting apparatus detachably secured to the workpiece by laterally spaced clamp assemblies engagable with the workpiece on opposite sides of the intended line of cut. A reciprocal cutter head is mounted between the clamp assemblies and is provided with a traveling abrasive cutting wire adapted to sever the workpiece normal to the longitudinal axis thereof. Dust and debris are withdrawn from the cutting area by a vacuum force through a nozzle mounted on the cutting head.

  12. Ion beam generating apparatus

    DOEpatents

    Brown, I.G.; Galvin, J.

    1987-12-22

    An ion generating apparatus utilizing a vacuum chamber, a cathode and an anode in the chamber. A source of electrical power produces an arc or discharge between the cathode and anode. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma is directed to an extractor which separates the electrons from the plasma, and accelerates the ions to produce an ion beam. 10 figs.

  13. Pruning apparatus and method

    DOEpatents

    Dellinger, R.D.

    1997-12-09

    The present invention is an automated pruning apparatus that requires little or no follow-up hand pruning and requires no sensors to avoid supportive trunks or posts. The present invention uses at least one pair of flat, close angled toothed, counter rotating blades. Woody branches are directed to the counter rotating blades first with a lifting arm and secondly by a quilled drum. 16 figs.

  14. HHT-based AE characteristics of natural fatigue cracks in rotating shafts

    NASA Astrophysics Data System (ADS)

    Lin, Li; Chu, Fulei

    2012-01-01

    This paper addresses an application of recently developed Hilbert-Huang transform (HHT) signal processing technique on AE feature extraction of natural fatigue cracks in rotating shafts providing an energy-frequency-time distribution with adaptable precision. A special purpose built test rig was employed for generating natural rotating fatigue crack on a shaft. Acoustic emission signals are non-stationary and nonlinear transients, whose waveforms and arrival times are unknown. A common problem in AE signal processing is to extract physical parameters of interest when these involve joint variations of time and frequency. It has been found that HHT appears to be a better tool compared to fast Fourier transform and continuous wavelet transform for natural fatigue crack characterization in a rotating rotor in all experiment cases. It was concluded that HHT-based AE technology successfully extracted the features of natural fatigue cracks induced on rotating shafts.

  15. Fracture mechanics and corrosion fatigue.

    NASA Technical Reports Server (NTRS)

    Mcevily, A. J.; Wei, R. P.

    1972-01-01

    Review of the current state-of-the-art in fracture mechanics, particularly in relation to the study of problems in environment-enhanced fatigue crack growth. The usefulness of this approach in developing understanding of the mechanisms for environmental embrittlement and its engineering utility are discussed. After a brief review of the evolution of the fracture mechanics approach and the study of environmental effects on the fatigue behavior of materials, a study is made of the response of materials to fatigue and corrosion fatigue, the modeling of the mechanisms of the fatigue process is considered, and the application of knowledge of fatigue crack growth to the prediction of the high cycle life of unnotched specimens is illustrated.

  16. Compassion fatigue: a nurse's primer.

    PubMed

    Lombardo, Barbara; Eyre, Caryl

    2011-01-01

    Most nurses enter the field of nursing with the intent to help others and provide empathetic care for patients with critical physical, mental, emotional, and spiritual needs. Empathic and caring nurses, however, can become victims of the continuing stress of meeting the often overwhelming needs of patients and their families, resulting in compassion fatigue. Compassion fatigue affects not only the nurse in terms of job satisfaction and emotional and physical health, but also the workplace environment by decreasing productivity and increasing turnover. We begin this article with a case study of a reactive nurse who did not seek help for her continuing stress. This is followed by a review of Watson's theoretical perspective related to compassion fatigue. Next we delineate symptoms of, and describe interventions for addressing compassion fatigue. We conclude by presenting a case study of a proactive nurse who avoided developing compassion fatigue and a discussion of future research needed to better prevent and ameliorate compassion fatigue. PMID:21800934

  17. Probabilistic Fatigue Damage Program (FATIG)

    NASA Technical Reports Server (NTRS)

    Michalopoulos, Constantine

    2012-01-01

    FATIG computes fatigue damage/fatigue life using the stress rms (root mean square) value, the total number of cycles, and S-N curve parameters. The damage is computed by the following methods: (a) traditional method using Miner s rule with stress cycles determined from a Rayleigh distribution up to 3*sigma; and (b) classical fatigue damage formula involving the Gamma function, which is derived from the integral version of Miner's rule. The integration is carried out over all stress amplitudes. This software solves the problem of probabilistic fatigue damage using the integral form of the Palmgren-Miner rule. The software computes fatigue life using an approach involving all stress amplitudes, up to N*sigma, as specified by the user. It can be used in the design of structural components subjected to random dynamic loading, or by any stress analyst with minimal training for fatigue life estimates of structural components.

  18. Creep-Fatigue Interaction Testing

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.

    2001-01-01

    Fatigue fives in metals are nominally time independent below 0.5 T(sub Melt). At higher temperatures, fatigue lives are altered due to time-dependent, thermally activated creep. Conversely, creep rates are altered by super. imposed fatigue loading. Creep and fatigue generally interact synergistically to reduce material lifetime. Their interaction, therefore, is of importance to structural durability of high-temperature structures such as nuclear reactors, reusable rocket engines, gas turbine engines, terrestrial steam turbines, pressure vessel and piping components, casting dies, molds for plastics, and pollution control devices. Safety and lifecycle costs force designers to quantify these interactions. Analytical and experimental approaches to creep-fatigue began in the era following World War II. In this article experimental and life prediction approaches are reviewed for assessing creep-fatigue interactions of metallic materials. Mechanistic models are also discussed briefly.

  19. Fatigue in systemic lupus erythematosus

    PubMed Central

    Ahn, Grace E; Ramsey-Goldman, Rosalind

    2012-01-01

    Systemic lupus erythematosus is a chronic inflammatory autoimmune disease often characterized by fatigue, with significant effects on physical functioning and wellbeing. The definition, prevalence and factors associated with fatigue, including physical activity, obesity, sleep, depression, anxiety, mood, cognitive dysfunction, vitamin D deficiency/insufficiency, pain, effects of medications and comorbidities, as well as potential therapeutic options of fatigue in the systemic lupus erythematosus population are reviewed. Due to variability in the reliability and validity of various fatigue measures used in clinical studies, clinical trial data have been challenging to interpret. Further investigation into the relationships between these risk factors and fatigue, and improved measures of fatigue, may lead to an improvement in the management of this chronic inflammatory disease. PMID:22737181

  20. Fatigue of fiberglass beam substructures

    SciTech Connect

    Mandell, J.F.; Combs, D.W.; Samborsky, D.D.

    1995-09-01

    Composite material beams representative of wind turbine blade substructure have been designed, fabricated, and tested under constant amplitude flexural fatigue loading. Beam stiffness, strength, and fatigue life are predicted based on detailed finite element analysis and the materials fatigue database developed using standard test coupons and special high frequency minicoupons.Beam results are in good agreement with predictions when premature adhesive and delamination failures are avoided in the load transfer areas. The results show that fiberglass substructures can be designed and fabricated to withstand maximum strain levels on the order of 8,000 microstrain for about 10{sup 6} cycles with proper structural detail design and the use of fatigue resistant laminate constructions. The study also demonstrates that the materials fatigue database and accurate analysis can be used to predict the fatigue life of composite substructures typical of blades.

  1. Vortex Apparatus and Demonstrations

    NASA Astrophysics Data System (ADS)

    Shakerin, Said

    2010-05-01

    Vortex flow, from millimeter to kilometer in scale, is important in many scientific and technological areas. Examples are seen in water strider locomotion, from industrial pipe flow (wastewater treatment) to air traffic control (safe distance between aircrafts on a runway ready for takeoff) to atmospheric studies.2-5 In this paper, we focus on a particular vortex known as bathtub vortex (BTV). It occurs when water is drained from a hole at the bottom of a container such as a bathtub or a sink under the action of gravity. The vortex has a funnel shape with a central air core, resembling a tornado. We have designed a portable apparatus to demonstrate bathtub vortex on a continual basis. The apparatus consists of a clear cylinder supported by a frame over a water reservoir and a submersible pump. Young and old have been equally amazed by watching the demonstrations at various public presentations held at the University of the Pacific recently. With material cost of less than 100, the apparatus can be easily fabricated and used at other universities. With a short set-up time, it is an ideal device for promoting science to the general public, and it can be used to enhance lectures in physics courses as well.

  2. Air-cleaning apparatus

    SciTech Connect

    Howard, A.G.

    1981-08-18

    An air-cleaning, heat-exchange apparatus includes a main housing portion connected by means of an air inlet fan to the kitchen exhaust stack of a restaurant. The apparatus includes a plurality of heat exchangers through which a heat-absorptive fluid is circulated, simultaneously, by means of a suitable fluid pump. These heat exchangers absorb heat from the hot exhaust gas, out of the exhaust stack of the restaurant, which flows over and through these heat exchangers and transfers this heat to the circulating fluid which communicates with remote heat exchangers. These remote heat exchangers further transfer this heat to a stream of air, such as that from a cold-air return duct for supplementing the conventional heating system of the restaurant. Due to the fact that such hot exhaust gas is heavily grease laden , grease will be deposited on virtually all internal surfaces of the apparatus which this exhaust gas contacts. Consequently, means are provided for spraying these contacted internal surfaces , as well as the hot exhaust gas itself, with a detergent solution in which the grease is soluble, thereby removing grease buildup from these internal surfaces.

  3. Radioactive waste processing apparatus

    DOEpatents

    Nelson, Robert E.; Ziegler, Anton A.; Serino, David F.; Basnar, Paul J.

    1987-01-01

    Apparatus for use in processing radioactive waste materials for shipment and storage in solid form in a container is disclosed. The container includes a top, and an opening in the top which is smaller than the outer circumference of the container. The apparatus includes an enclosure into which the container is placed, solution feed apparatus for adding a solution containing radioactive waste materials into the container through the container opening, and at least one rotatable blade for blending the solution with a fixing agent such as cement or the like as the solution is added into the container. The blade is constructed so that it can pass through the opening in the top of the container. The rotational axis of the blade is displaced from the center of the blade so that after the blade passes through the opening, the blade and container can be adjusted so that one edge of the blade is adjacent the cylindrical wall of the container, to insure thorough mixing. When the blade is inside the container, a substantially sealed chamber is formed to contain vapors created by the chemical action of the waste solution and fixant, and vapors emanating through the opening in the container.

  4. Acoustic hemostasis

    NASA Astrophysics Data System (ADS)

    Crum, Lawrence; Beach, Kirk; Carter, Stephen; Chandler, Wayne; Curra, Francesco; Kaczkowski, Peter; Keilman, George; Khokhlova, Vera; Martin, Roy; Mourad, Pierre; Vaezy, Shahram

    2000-07-01

    In cases of severe injury, physicians speak of a "golden hour"—a brief grace period in which quickly applied, proper therapy can save the life of the patient. Much of this mortality results from exsanguination, i.e., bleeding to death—often from internal hemorrhage. The inability of a paramedic to treat breaches in the vascular system deep within the body or to stem the loss of blood from internal organs is a major reason for the high level of mortality associated with blunt trauma. We have undertaken an extensive research program to treat the problem of internal bleeding. Our approach is as follows: (a) We use scanning ultrasound to identify internal bleeding and hemorrhage, (b) we use ultrasound imaging to locate specific breaches in the vascular system, both from damaged vessels and gross damage to the capillary bed, and (c) we use High Intensity Focused Ultrasound (HIFU) to treat the damaged region and to induce hemostasis. We present a general review of this research with some emphasis on the role of nonlinear acoustics.

  5. Post Test Evaluation of HSCT Nozzle Acoustic Liner Subcomponents Subjected to a Hot Acoustic Durability Test

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; Lee, Kuan

    2008-01-01

    The acoustic liner system designed for use in the High Speed Civil Transport (HSCT) was tested in a thermal-acoustic environment. Five ceramic matrix composite (CMC) acoustic tile configurations, five bulk acoustic absorbers, and one thermal protection system design were tested. The CMC acoustic tiles were subjected to two 2 3/4 hr ambient temperature acoustic exposures to measure their dynamic response. One exposure was conducted on the tiles alone and the second exposure included the tiles and the T-foam bulk absorber. The measured tile RMS strains were small. With or without the T-foam absorber, the dynamic strains were below strain levels that would cause damage during fatigue loading. After the ambient exposure, a 75-hr durability test of the entire acoustic liner system was conducted using a thermal-acoustic cycle that approximated the anticipated service cycle. Acoustic loads up to 139 dB/Hz and temperatures up to 1670 F (910 C) were employed during this 60 cycle test. During the durability test, the CMC tiles were exposed to temperatures up to 1780 F and a transient through thickness gradient up to 490 F. The TPS peak temperatures on the hot side of the panels ranged from 750 to 1000 F during the 60 cycles. The through thickness delta T ranged from 450 to 650 F, varying with TPS location and cycle number. No damage, such as cracks or chipping, was observed in the CMC tiles after completion of the testing. However, on tile warped during the durability test and was replaced after 43 or 60 cycles. No externally observed damage was found in this tile. No failure of the CMC fasteners occurred, but damage was observed. Cracks and missing material occurred, only in the fastener head region. No indication of damage was observed in the T-foam acoustic absorbers. The SiC foam acoustic absorber experienced damage after about 43 cycles. Cracking in the TPS occurred around the attachment holes and under a vent. In spite of the development of damage, the TPS maintained

  6. Determinants of fatigue and stress

    PubMed Central

    2011-01-01

    Background Fatigue can be triggered by previous perceived stress which may lead to impairment of performance and function. The purpose of the study was to investigate the relationship between fatigue and perceived stress. Method Health determinants including sociodemographic factors for associations between fatigue and perceived stress in the general population (N = 2,483) are outlined. Fatigue and stress were assessed with the Chalder Fatigue Scale (CFS) and the Perceived Stress Questionnaire (PSQ). Results Within the general population, 25.9% of male and 34.5% of female respondents reported moderate fatigue during the last six months; 9.7% of subjects reported substantial fatigue lasting six months or longer. An adjusted regression analysis (R2corr = .28, p < .001) showed that fatigue is highest associated with perceived stress and self-perceived health status. The following factors were correlated with increased rates of fatigue and perceived stress: female gender, divorce/separation, low social class and poor health status. Conclusion We conclude that the two conditions overlap most in terms of socio-economic status and self-perceived health status. PMID:21774803

  7. Acoustic source for generating an acoustic beam

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  8. Concurrent cognitive task may improve motor work performance and reduce muscle fatigue.

    PubMed

    Evstigneeva, Maria; Aleksandrov, Aleksandr; Mathiassen, Svend Erik; Lyskov, Eugene

    2012-01-01

    Performance of certain cognitive tasks either during physical load or in rest pauses between boosts might lead to slowing of muscle fatigue and fatigue related decline in performance. Seventeen right-handed healthy volunteers (age 24 ± 1.4, 8 males) participated in this study, aiming to investigate the effect of the level of the cognitive information processing - 1) passive perception of audio stimuli, 2) active stimuli discrimination, 3) active stimuli discrimination following motor response - on motor task performance (handgrip test 30% and 7% of MVC) and muscle fatigue development. Cognitive tasks show the following effects on motor work: i) Perceived fatigue during 30 % MVC (fatiguing) condition developed slower if participant pressed button in response to deviant acoustic stimuli, as compared to passive listening. Counting task, an active task without motor component, took the intermediate position and did not differ significantly from two other cognitive tasks. ii) MVC after 30% MVC (fatiguing) condition tended to decrease stronger when accompanied with passive listening in comparison with both active tasks. iii) Motor task performance during 30% MVC (fatiguing) condition was better for active cognitive task with motor component than for passive task. Active task without motor component took the intermediate position and did not differ significantly from both the other cognitive tasks. PMID:22317158

  9. Bithermal fatigue: A simplified alternative to thermomechanical fatigue

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.

    1988-01-01

    A bithermal fatigue test technique was proposed as a simplified alternative to the thermomechanical fatigue test. Both the thermomechanical cycle and the bithermal technique can be used to study nonisothermal fatigue behavior. The difference between the two cycles is that in a conventional thermomechanical fatigue cycle the temperature is continuously varied concurrently with the applied mechanical strains, but in the bithermal fatigue cycle the specimen is held at zero load during the temperature excursions and all the loads are applied at the two extreme temperatures of the cycle. Experimentally, the bithermal fatigue test technique offers advantages such as ease in synchronizing the temperature and mechanical strain waveforms, in minimizing temperature gradients in the specimen gauge length, and in reducing and interpreting thermal fatigue such as the influence of alternate high and low temperatures on the cyclic stress-strain response characteristics, the effects of thermal state, and the possibility of introducing high- and low-temperature deformation mechanisms within the same cycle. The bithermal technique was used to study nonisothermal fatigue behavior of alloys such as single-crystal PWA 1480, single-crystal Rene N4, cast B1900+Hf, and wrought Haynes 188.

  10. Nonlinear ultrasonic measurements with EMATs for detecting pre-cracking fatigue damage

    NASA Astrophysics Data System (ADS)

    Cobb, A.; Capps, M.; Duffer, C.; Feiger, J.; Robinson, K.; Hollingshaus, B.

    2012-05-01

    This paper describes an approach for measuring material degradation using nonlinear acoustics. The importance of this measurement is that prior efforts have shown that the degree of acoustic nonlinearity increases as a function of fatigue damage accumulation. By exploiting this physical mechanism, there is the potential to develop methods for measuring the remaining life of critical components. The challenge with existing approaches for measuring acoustic nonlinearity is that primarily they have only been shown to be successful in a laboratory setting. This paper presents a potential approach for field measurement of acoustic nonlinearity that utilizes Rayleigh waves generated from electromagnetic acoustic transducers (EMATs). Rayleigh waves have unique advantages because the sound propagates along the surface, allowing for application on complex engineering structures. EMATs were used in place of traditional piezoelectric transducers because the sound is generated directly in the metallic structure, eliminating the need for sound coupling fluids that are a source of variability. Custom EMATs were developed and nonlinearity measurements were performed on 410 stainless steel specimens that were subjected to a fatigue process. Some experiments showed an increase in the acoustic nonlinearity of up to 500% compared to the unfatigued value. Other experiments had too much scatter and did not show this relationship consistently due to unanticipated challenges in producing repeatable measurements. Lessons learned from the project effort will be presented to potentially improve the repeatability of the measurement approach. If the scatter can be reduced, this EMAT-based technique could result in a field deployable prognosis tool.

  11. Canonical Acoustics and Its Application to Surface Acoustic Wave on Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shen, Jian Qi

    2016-08-01

    In a conventional formalism of acoustics, acoustic pressure p and velocity field u are used for characterizing acoustic waves propagating inside elastic/acoustic materials. We shall treat some fundamental problems relevant to acoustic wave propagation alternatively by using canonical acoustics (a more concise and compact formalism of acoustic dynamics), in which an acoustic scalar potential and an acoustic vector potential (Φ ,V), instead of the conventional acoustic field quantities such as acoustic pressure and velocity field (p,u) for characterizing acoustic waves, have been defined as the fundamental variables. The canonical formalism of the acoustic energy-momentum tensor is derived in terms of the acoustic potentials. Both the acoustic Hamiltonian density and the acoustic Lagrangian density have been defined, and based on this formulation, the acoustic wave quantization in a fluid is also developed. Such a formalism of acoustic potentials is employed to the problem of negative-mass-density assisted surface acoustic wave that is a highly localized surface bound state (an eigenstate of the acoustic wave equations). Since such a surface acoustic wave can be strongly confined to an interface between an acoustic metamaterial (e.g., fluid-solid composite structures with a negative dynamical mass density) and an ordinary material (with a positive mass density), it will give rise to an effect of acoustic field enhancement on the acoustic interface, and would have potential applications in acoustic device design for acoustic wave control.

  12. What Is an Acoustic Neuroma

    MedlinePlus

    ... Acoustic Neuroma An acoustic neuroma, also called a vestibular schwannoma, is a rare benign tumor of the ... Acoustic Neuroma? An acoustic neuroma, known as a vestibular schwannoma, is a benign (non-cancerous) growth that ...

  13. Optoelectronic Apparatus Measures Glucose Noninvasively

    NASA Technical Reports Server (NTRS)

    Ansari, Rafat R.; Rovati, Luigi L.

    2003-01-01

    An optoelectronic apparatus has been invented as a noninvasive means of measuring the concentration of glucose in the human body. The apparatus performs polarimetric and interferometric measurements of the human eye to acquire data from which the concentration of glucose in the aqueous humor can be computed. Because of the importance of the concentration of glucose in human health, there could be a large potential market for instruments based on this apparatus.

  14. Complete liquefaction methods and apparatus

    SciTech Connect

    Turner, Terry D.; Wilding, Bruce M.

    2013-10-15

    A method and apparatus are described to provide complete gas utilization in the liquefaction operation from a source of gas without return of natural gas to the source thereof from the process and apparatus. The mass flow rate of gas input into the system and apparatus may be substantially equal to the mass flow rate of liquefied product output from the system, such as for storage or use.

  15. Apparatus Would Stain Microscope Slides

    NASA Technical Reports Server (NTRS)

    Breeding, James D.

    1993-01-01

    Proposed apparatus meters specific amounts of fluid out of containers at specific times to stain microscope slides. Intended specifically for semiautomated staining of microbiological and hematological samples in microgravity, leakproof apparatus used in other environments in which technicians have little time to allocate to staining procedures and/or exposure to toxic staining agents or to micro-organisms to be stained hazardous. Apparatus adapted to perform almost any staining procedure and accommodates multiple staining reagents, useful for small or remote clinical laboratories.

  16. Fatigue crack tip deformation and fatigue crack propagation

    NASA Technical Reports Server (NTRS)

    Kang, T. S.; Liu, H. W.

    1972-01-01

    The effects of stress ratio, prestress cycling and plate thickness on the fatigue crack propagation rate are studied on 2024-T351 aluminum alloy. Fatigue crack propagation rate increases with the plate thickness and the stress ratio. Prestress cycling below the static yield strength has no noticeable effect on the fatigue crack propagation rate. However, prestress cycling above the static yield strength causes the material to strain harden and increases the fatigue crack propagation rate. Crack tip deformation is used to study the fatigue crack propagation. The crack tip strains and the crack opening displacements were measured from moire fringe patterns. The moire fringe patterns were obtained by a double exposure technique, using a very high density master grille (13,400 lines per inch).

  17. Acoustic measurements of F-4E aircraft operating in hush house, NSN 4920-02-070-2721

    NASA Astrophysics Data System (ADS)

    Miller, V. R.; Plzak, G. A.; Chinn, J. M.

    1981-09-01

    The primary purpose of this test program was to measure the acoustic environment in the hush house facility located at Kelly Air Force Base, Texas, during operation of the F-4E aircraft to ensure that aircraft structural acoustic design limits were not exceeded. The acoustic measurements showed that sonic fatigue problems are anticipated with the F-4E aircraft aft fuselage structure during operation in the hush house. The measured acoustic levels were less than those measured in an F-4E aircraft water cooled hush house at Hill AFB in the lower frequencies, but were increased over that measured during ground run up on some areas of the aircraft. It was recommended that the acoustic loads measured in this program should be specified in the structural design criteria for aircraft which will be subjected to hush house operation or defining requirements for associated equipment. Recommendations were also made to increase the fatigue life of the aft fuselage.

  18. Borehole sealing method and apparatus

    DOEpatents

    Hartley, James N.; Jansen, Jr., George

    1977-01-01

    A method and apparatus is described for sealing boreholes in the earth. The borehole is blocked at the sealing level, and a sealing apparatus capable of melting rock and earth is positioned in the borehole just above seal level. The apparatus is heated to rock-melting temperature and powdered rock or other sealing material is transported down the borehole to the apparatus where it is melted, pooling on the mechanical block and allowed to cool and solidify, sealing the hole. Any length of the borehole can be sealed by slowly raising the apparatus in the borehole while continuously supplying powdered rock to the apparatus to be melted and added to the top of the column of molten and cooling rock, forming a continuous borehole seal. The sealing apparatus consists of a heater capable of melting rock, including means for supplying power to the heater, means for transporting powdered rock down the borehole to the heater, means for cooling the apparatus and means for positioning the apparatus in the borehole.

  19. Pellet inspection apparatus

    DOEpatents

    Wilks, Robert S.; Taleff, Alexander; Sturges, Jr., Robert H.

    1982-01-01

    Apparatus for inspecting nuclear fuel pellets in a sealed container for diameter, flaws, length and weight. The apparatus includes, in an array, a pellet pick-up station, four pellet inspection stations and a pellet sorting station. The pellets are delivered one at a time to the pick-up station by a vibrating bowl through a vibrating linear conveyor. Grippers each associated with a successive pair of the stations are reciprocable together to pick up a pellet at the upstream station of each pair and to deposit the pellet at the corresponding downstream station. The gripper jaws are opened selectively depending on the state of the pellets at the stations and the particular cycle in which the apparatus is operating. Inspection for diameter, flaws and length is effected in each case by a laser beam projected on the pellets by a precise optical system while each pellet is rotated by rollers. Each laser and its optical system are mounted in a container which is free standing on a precise surface and is provided with locating buttons which engage locating holes in the surface so that each laser and its optical system is precisely set. The roller stands are likewise free standing and are similarly precisely positioned. The diameter optical system projects a thin beam of light which scans across the top of each pellet and is projected on a diode array. The fl GOVERNMENT CONTRACT CLAUSE The invention herein described was made in the course of or under a contract or subcontract thereunder with the Department of Energy bearing No. EY-67-14-C-2170.

  20. Belt conveyor apparatus

    SciTech Connect

    Oakley, D.J.; Bogart, R.L.

    1987-05-05

    A belt conveyor apparatus is described comprising: means defining a conveyance path including a first pulley and at least a second pulley, an endless belt member adapted for continuous travel about the pulleys defining thereby an upper and lower reach, the endless belt member having a lower portion which engages the pulleys and an integral upper portion adapted to receive objects at a first location on the conveyance path and transport the objects to and then discharge the objects at a second location on the conveyance path; and motive means in communication with the means defining a conveyance path, for effecting the travel of the endless belt member about the conveyance path.

  1. Municipal waste processing apparatus

    DOEpatents

    Mayberry, J.L.

    1988-04-13

    This invention relates to apparatus for processing municipal waste, and more particularly to vibrating mesh screen conveyor systems for removing grit, glass, and other noncombustible materials from dry municipal waste. Municipal waste must be properly processed and disposed of so that it does not create health risks to the community. Generally, municipal waste, which may be collected in garbage trucks, dumpsters, or the like, is deposited in processing areas such as landfills. Land and environmental controls imposed on landfill operators by governmental bodies have increased in recent years, however, making landfill disposal of solid waste materials more expensive. 6 figs.

  2. Stack sampling apparatus

    DOEpatents

    Lind, Randall F; Lloyd, Peter D; Love, Lonnie J; Noakes, Mark W; Pin, Francois G; Richardson, Bradley S; Rowe, John C

    2014-09-16

    An apparatus for obtaining samples from a structure includes a support member, at least one stabilizing member, and at least one moveable member. The stabilizing member has a first portion coupled to the support member and a second portion configured to engage with the structure to restrict relative movement between the support member and the structure. The stabilizing member is radially expandable from a first configuration where the second portion does not engage with a surface of the structure to a second configuration where the second portion engages with the surface of the structure.

  3. Nitrogen fixation apparatus

    DOEpatents

    Chen, Hao-Lin

    1984-01-01

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

  4. Foil changing apparatus

    DOEpatents

    Crist, Charles E.; Ives, Harry C.; Leifeste, Gordon T.; Miller, Robert B.

    1988-01-01

    A self-contained hermetically sealed foil changer for advancing a portion of foil web into a position normal to the path of a high energy particle beam. The path of the beam is defined generally by an aperture plate and cooperating axially movable barrel such that the barrel can be advanced toward the plate thereby positioning a portion of the foil across the beam path and sealing the foil between the barrel and the plate to form a membrane across said beam path. A spooling apparatus contained in the foil changer permits selectively advancing a fresh supply of foil across the beam path without breaking the foil changer seal.

  5. Intracranial surgical operative apparatus

    NASA Technical Reports Server (NTRS)

    Sheldon, Charles H. (Inventor); Frazer, Robert E. (Inventor); Lutes, Harold R. (Inventor)

    1983-01-01

    Apparatus for operating on the brain with minimal disturbances thereto, including a bullet-shaped expandable device with an end that can be closed for insertion through a small hole in the brain. The device can be expanded after insertion to leave an air pocket through which to extend viewing and cutting devices which enable operation on tumors or the like that lie at the end of the expanded device. A set of probes of varying diameters are also provided, to progressively enlarge a passage leading to the tumor, prior to inserting the expandable device.

  6. Nuclear reactor control apparatus

    DOEpatents

    Sridhar, Bettadapur N.

    1983-11-01

    Nuclear reactor core safety rod release apparatus comprises a control rod having a detent notch in the form of an annular peripheral recess at its upper end, a control rod support tube for raising and lowering the control rod under normal conditions, latches pivotally mounted on the control support tube with free ends thereof normally disposed in the recess in the control rod, and cam means for pivoting the latches out of the recess in the control rod when a scram condition occurs. One embodiment of the invention comprises an additional magnetically-operated latch for releasing the control rod under two different conditions, one involving seismic shock.

  7. DNA Sequencing apparatus

    DOEpatents

    Tabor, Stanley; Richardson, Charles C.

    1992-01-01

    An automated DNA sequencing apparatus having a reactor for providing at least two series of DNA products formed from a single primer and a DNA strand, each DNA product of a series differing in molecular weight and having a chain terminating agent at one end; separating means for separating the DNA products to form a series bands, the intensity of substantially all nearby bands in a different series being different, band reading means for determining the position an This invention was made with government support including a grant from the U.S. Public Health Service, contract number AI-06045. The U.S. government has certain rights in the invention.

  8. CRANE POSITIONING APPARATUS

    DOEpatents

    Landsiedel, F.W.; Wolff, H.

    1960-06-28

    An apparatus is described for automatically accomplishing the final accurate horizontal positioning of a crane after the latter has been placed to within 1/8 in. of its selected position. For this purpose there is provided a tiltable member on the crane mast for lowering into contact with a stationary probe. Misalignment of the tiltable member, with respect to the probe as the member is lowered, causes tilting of the latter to actuate appropriate switches that energize motors for bringing the mast into proper position. When properly aligned the member is not tilted and a central switch is actuated to indicate the final alignment of the crane.

  9. Apparatus for chemical synthesis

    DOEpatents

    Kong, Peter C.; Herring, J. Stephen; Grandy, Jon D.

    2011-05-10

    A method and apparatus for forming a chemical hydride is described and which includes a pseudo-plasma-electrolysis reactor which is operable to receive a solution capable of forming a chemical hydride and which further includes a cathode and a movable anode, and wherein the anode is moved into and out of fluidic, ohmic electrical contact with the solution capable of forming a chemical hydride and which further, when energized produces an oxygen plasma which facilitates the formation of a chemical hydride in the solution.

  10. Solder dross removal apparatus

    NASA Technical Reports Server (NTRS)

    Webb, Winston S. (Inventor)

    1990-01-01

    An automatic dross removal apparatus is disclosed for removing dross from the surface of a solder bath in an automated electric component handling system. A rotatable wiper blade is positioned adjacent the solder bath which skims the dross off of the surface prior to the dipping of a robot conveyed component into the bath. An electronic control circuit causes a motor to rotate the wiper arm one full rotational cycle each time a pulse is received from a robot controller as a component approaches the solder bath.

  11. Solder dross removal apparatus

    NASA Technical Reports Server (NTRS)

    Webb, Winston S. (Inventor)

    1992-01-01

    An automatic dross removal apparatus (10) is disclosed for removing dross from the surface of a solder bath (22) in an automated electric component handling system. A rotatable wiper blade (14) is positioned adjacent the solder bath (22) which skims the dross off of the surface prior to the dipping of a robot conveyed component into the bath. An electronic control circuit (34) causes a motor (32) to rotate the wiper arm (14) one full rotational cycle each time a pulse is received from a robot controller (44) as a component approaches the solder bath (22).

  12. Fireplace and stove apparatus

    SciTech Connect

    Evans, J.L.

    1983-11-15

    A fireplace or stove apparatus is disclosed for efficiently providing heat to a structure without loss of interior air to the flue draft. A blower forces outside air through a conduit located in the exhaust flue into a grate located in a fireplace or stove. The fuel loading opening of the fireplace or stove is made substantially air-tightly sealed. An air opening in the grate provides air to be consumed by the fire. A second air opening in the grate is fluidly connected by means of a conduit to the structure to be heated.

  13. Vapor Diffusion Apparatus

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Vapor Diffusion Apparatus (VDA and VDA-2) was developed by the University of Alabama in Birmingham for NASA's Marshall Space Flight Center. In the original VDA, a protein solution and a precipitant are extruded by two plungers onto the tip of a small syringe and allowed to evaporate, raising the concentration and prompting protein molecules to crystallize. In the VDA-2 version, a third plunger was added to mix the two solutions before returning the mix to the syringe tip. The principal investigator is Dr. Larry Delucas of the University of Alabama in Birmingham

  14. Vapor Diffusion Apparatus

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Vapor Diffusion Apparatus (VDA-2) was developed by the University of Alabama in Birmingham for NASA's Marshall Space Flight Center. In the original VDA, a protein solution and a precipitant are extruded by two plungers onto the tip of a small syringe and allowed to evaporate, raising the concentration and prompting protein molecules to crystallize. In the VDA-2 version, a third plunger was added to mix the two solutions before returning the mix to the syringe tip. The principal investigator is Dr. Larry Delucas of the University of Alabama in Birmingham.

  15. Stage cementing apparatus

    SciTech Connect

    Blamford, D.M.; Easter, J.H.

    1988-06-21

    A stage cementing apparatus for selectively passing cement from the interior passage of a casing to the annulus between the exterior of the casing and borehole, the casing having an upper portion and a lower portion, is described comprising: a barrel secured to the upper portion of the casing; a mandrel secured to the lower portion of the casing, and a stage cementing tool having a generally cylindrical configuration adapted for attachment to the lower end of the barrel about a portion of the mandrel.

  16. APPARATUS FOR ARC WELDING

    DOEpatents

    Lingafelter, J.W.

    1960-04-01

    An apparatus is described in which a welding arc created between an annular electrode and a workpiece moves under the influence of an electromagnetic field about the electrode in a closed or annular path. This mode of welding is specially suited to the enclosing of nuclear-fuel slugs in a protective casing. For example, a uranium slug is placed in an aluminum can, and an aluminum closure is welded to the open end of the can along a closed or annular path conforming to the periphery of the end closure.

  17. Thermal stir welding apparatus

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2011-01-01

    A welding method and apparatus are provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  18. Portable hydrogenerating apparatus

    SciTech Connect

    Borgren, P.M.

    1982-04-13

    Apparatus for generating hydroelectric power comprising a portable collector tube assembly which can be transported to the site of a water source having a waterfall sufficient in magnitude to provide a pressure head for driving a turbine generator. The tube assembly comprises telescopically arranged inner and outer tubes, and means for rotating the tube assembly and extending the inner tube so as to place the upper, extended end thereof in a position within and below the top of the waterfall so as to take advantage of the resulting hydrodynamic and hydrostatic forces.

  19. Symptoms of Acoustic Neuroma

    MedlinePlus

    ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...

  20. Acoustic Neuroma Educational Video

    MedlinePlus

    ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...