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Sample records for acoustic treatment design

  1. Design and performance of duct acoustic treatment

    NASA Technical Reports Server (NTRS)

    Motsinger, R. E.; Kraft, R. E.

    1991-01-01

    The procedure for designing acoustic treatment panels used to line the walls of aircraft engine ducts and for estimating the resulting suppression of turbofan engine duct noise is discussed. This procedure is intended to be used for estimating noise suppression of existing designs or for designing new acoustic treatment panels and duct configurations to achieve desired suppression levels.

  2. Acoustic Treatment Design Scaling Methods. Phase 2

    NASA Technical Reports Server (NTRS)

    Clark, L. (Technical Monitor); Parrott, T. (Technical Monitor); Jones, M. (Technical Monitor); Kraft, R. E.; Yu, J.; Kwan, H. W.; Beer, B.; Seybert, A. F.; Tathavadekar, P.

    2003-01-01

    The ability to design, build and test miniaturized acoustic treatment panels on scale model fan rigs representative of full scale engines provides not only cost-savings, but also an opportunity to optimize the treatment by allowing multiple tests. To use scale model treatment as a design tool, the impedance of the sub-scale liner must be known with confidence. This study was aimed at developing impedance measurement methods for high frequencies. A normal incidence impedance tube method that extends the upper frequency range to 25,000 Hz. without grazing flow effects was evaluated. The free field method was investigated as a potential high frequency technique. The potential of the two-microphone in-situ impedance measurement method was evaluated in the presence of grazing flow. Difficulties in achieving the high frequency goals were encountered in all methods. Results of developing a time-domain finite difference resonator impedance model indicated that a re-interpretation of the empirical fluid mechanical models used in the frequency domain model for nonlinear resistance and mass reactance may be required. A scale model treatment design that could be tested on the Universal Propulsion Simulator vehicle was proposed.

  3. Design of optimum acoustic treatment for rectangular ducts with flow

    NASA Technical Reports Server (NTRS)

    Motsinger, R. E.; Kraft, R. E.; Zwick, J. W.

    1976-01-01

    A design optimization technique for acoustic treatment in rectangular ducts with uniform mean flow is presented. The technique is based on the acoustic wave solution in terms of series of characteristic duct modes. The analysis allows multiple axial treatment sections along the length of the duct and requires a known modal characterization of the sound source. Conditions of acoustic pressure and acoustic velocity continuity are used to match modal solutions at planes of impedance discontinuity in the duct. Experimental techniques for obtaining this modal characterization are presented. Using duct modes measured at the source plane, the optimization technique is exercised to design an optimized single element liner in a case without mean flow, and optimized single and dual element liners in cases with mean flow. The validity of the program for predicting noise suppression is demonstrated by comparing analytical predictions with measured data for several (non-optimum) cases. Application to treatment design in turbomachinery exhaust ducts is considered.

  4. Optimizing acoustical treatment. [structural design criteria for theater

    NASA Technical Reports Server (NTRS)

    Beuran, N.; Ramboiu, S.; Farcas, I.; Halpert, E.

    1974-01-01

    A mathematical linear programming model is presented for optimizing acoustical treatment and interior decoration of concert and other public halls. This method provides the designer with a range of acoustically correct solutions at increased economical efficiency. The mathematical model uses geometrical data about the room, recommended reverberation time values, the architect's choice of given sound absorbing structures and finishing materials. The model permits inclusion of aesthetical considerations about conditioning, proportioning, or, on the contrary, reciprocal exclusion of any classes of material and/or sound absorbing structure.

  5. A Requirements-Driven Optimization Method for Acoustic Treatment Design

    NASA Technical Reports Server (NTRS)

    Berton, Jeffrey J.

    2016-01-01

    Acoustic treatment designers have long been able to target specific noise sources inside turbofan engines. Facesheet porosity and cavity depth are key design variables of perforate-over-honeycomb liners that determine levels of noise suppression as well as the frequencies at which suppression occurs. Layers of these structures can be combined to create a robust attenuation spectrum that covers a wide range of frequencies. Looking to the future, rapidly-emerging additive manufacturing technologies are enabling new liners with multiple degrees of freedom, and new adaptive liners with variable impedance are showing promise. More than ever, there is greater flexibility and freedom in liner design. Subject to practical considerations, liner design variables may be manipulated to achieve a target attenuation spectrum. But characteristics of the ideal attenuation spectrum can be difficult to know. Many multidisciplinary system effects govern how engine noise sources contribute to community noise. Given a hardwall fan noise source to be suppressed, and using an analytical certification noise model to compute a community noise measure of merit, the optimal attenuation spectrum can be derived using multidisciplinary systems analysis methods. The subject of this paper is an analytical method that derives the ideal target attenuation spectrum that minimizes noise perceived by observers on the ground.

  6. Acoustic Characteristics of Various Treatment Panel Designs for HSCT Ejector Liner Acoustic Technology Development Program

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Kraft, R. E.; Syed, A. a.; Vu, D. D.; Mungur, P.; Langenbrunner, L. E.; Majjigi, R. K.

    2006-01-01

    The objectives of the initial effort (Phase I) of HSR Liner Technology Program, the selection of promising liner concepts, design and fabrication of these concepts for laboratory tests, testing these liners in the laboratory by using impedance tube and flow ducts, and developing empirical impedance/suppression correlation, are successfully completed. Acoustic and aerodynamic criteria for the liner design are established. Based on these criteria several liners are designed. The liner concepts designed and fabricated include Single-Degree-of-Freedom (SDOF), Two-Degree-of-Freedom (2DOF), and Bulk Absorber. Two types of SDOF treatment are fabricated, one with a perforated type face plate and the other with a wiremesh (woven) type faceplate. In addition, special configurations of these concepts are also included in the design. Several treatment panels are designed for parametric study. In these panels the facesheets of different porosity, hole diameter, and sheet thickness are utilized. Several deep panels (i.e., 1 in. deep) are designed and instrumented to measure DC flow resistance and insitu impedance in the presence of grazing flow. Basic components of these panels (i.e., facesheets, bulk materials, etc.) are also procured and tested. The results include DC flow resistance, normal impedance, and insertion loss.

  7. Acoustic Treatment Design Scaling Methods. Volume 3; Test Plans, Hardware, Results, and Evaluation

    NASA Technical Reports Server (NTRS)

    Yu, J.; Kwan, H. W.; Echternach, D. K.; Kraft, R. E.; Syed, A. A.

    1999-01-01

    The ability to design, build, and test miniaturized acoustic treatment panels on scale-model fan rigs representative of the full-scale engine provides not only a cost-savings, but an opportunity to optimize the treatment by allowing tests of different designs. To be able to use scale model treatment as a full-scale design tool, it is necessary that the designer be able to reliably translate the scale model design and performance to an equivalent full-scale design. The primary objective of the study presented in this volume of the final report was to conduct laboratory tests to evaluate liner acoustic properties and validate advanced treatment impedance models. These laboratory tests include DC flow resistance measurements, normal incidence impedance measurements, DC flow and impedance measurements in the presence of grazing flow, and in-duct liner attenuation as well as modal measurements. Test panels were fabricated at three different scale factors (i.e., full-scale, half-scale, and one-fifth scale) to support laboratory acoustic testing. The panel configurations include single-degree-of-freedom (SDOF) perforated sandwich panels, SDOF linear (wire mesh) liners, and double-degree-of-freedom (DDOF) linear acoustic panels.

  8. Acoustic Treatment Design Scaling Methods. Volume 1; Overview, Results, and Recommendations

    NASA Technical Reports Server (NTRS)

    Kraft, R. E.; Yu, J.

    1999-01-01

    Scale model fan rigs that simulate new generation ultra-high-bypass engines at about 1/5-scale are achieving increased importance as development vehicles for the design of low-noise aircraft engines. Testing at small scale allows the tests to be performed in existing anechoic wind tunnels, which provides an accurate simulation of the important effects of aircraft forward motion on the noise generation. The ability to design, build, and test miniaturized acoustic treatment panels on scale model fan rigs representative of the fullscale engine provides not only a cost-savings, but an opportunity to optimize the treatment by allowing tests of different designs. The primary objective of this study was to develop methods that will allow scale model fan rigs to be successfully used as acoustic treatment design tools. The study focuses on finding methods to extend the upper limit of the frequency range of impedance prediction models and acoustic impedance measurement methods for subscale treatment liner designs, and confirm the predictions by correlation with measured data. This phase of the program had as a goal doubling the upper limit of impedance measurement from 6 kHz to 12 kHz. The program utilizes combined analytical and experimental methods to achieve the objectives.

  9. Quiet Clean Short-Haul Experimental Engine (QCSEE): Acoustic treatment development and design

    NASA Technical Reports Server (NTRS)

    Clemons, A.

    1979-01-01

    Acoustic treatment designs for the quiet clean short-haul experimental engines are defined. The procedures used in the development of each noise-source suppressor device are presented and discussed in detail. A complete description of all treatment concepts considered and the test facilities utilized in obtaining background data used in treatment development are also described. Additional supporting investigations that are complementary to the treatment development work are presented. The expected suppression results for each treatment configuration are given in terms of delta SPL versus frequency and in terms of delta PNdB.

  10. Acoustic Treatment Design Scaling Methods. Volume 2; Advanced Treatment Impedance Models for High Frequency Ranges

    NASA Technical Reports Server (NTRS)

    Kraft, R. E.; Yu, J.; Kwan, H. W.

    1999-01-01

    The primary purpose of this study is to develop improved models for the acoustic impedance of treatment panels at high frequencies, for application to subscale treatment designs. Effects that cause significant deviation of the impedance from simple geometric scaling are examined in detail, an improved high-frequency impedance model is developed, and the improved model is correlated with high-frequency impedance measurements. Only single-degree-of-freedom honeycomb sandwich resonator panels with either perforated sheet or "linear" wiremesh faceplates are considered. The objective is to understand those effects that cause the simple single-degree-of- freedom resonator panels to deviate at the higher-scaled frequency from the impedance that would be obtained at the corresponding full-scale frequency. This will allow the subscale panel to be designed to achieve a specified impedance spectrum over at least a limited range of frequencies. An advanced impedance prediction model has been developed that accounts for some of the known effects at high frequency that have previously been ignored as a small source of error for full-scale frequency ranges.

  11. Indoor acoustic gain design

    NASA Astrophysics Data System (ADS)

    Concha-Abarca, Justo Andres

    2002-11-01

    The design of sound reinforcement systems includes many variables and usually some of these variables are discussed. There are criteria to optimize the performance of the sound reinforcement systems under indoor conditions. The equivalent acoustic distance, the necessary acoustic gain, and the potential acoustic gain are parameters which must be adjusted with respect to the loudspeaker array, electric power and directionality of loudspeakers, the room acoustics conditions, the distance and distribution of the audience, and the type of the original sources. The design and installation of front of the house and monitoring systems have individual criteria. This article is about this criteria and it proposes general considerations for the indoor acoustic gain design.

  12. Acoustic Characteristics of Various Treatment Panel Designs Specific to HSCT Mixer-Ejector Application

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Kinzie, K.; Vu, D. D.; Langenbrunner, L. E.; Szczepkowski, G. T.

    2006-01-01

    The development process of liner design methodology is described in several reports. The results of the initial effort of concept development, screening, laboratory testing of various liner concepts, and preliminary correlation (generic data) are presented in a report Acoustic Characteristics of Various Treatment Panel Designs for HSCT Ejector Liner Acoustic Technology Development Program. The second phase of laboratory test results of more practical concepts and their data correlations are presented in this report (product specific). In particular, this report contains normal incidence impedance measurements of several liner types in both a static rig and in a high temperature flow duct rig. The flow duct rig allows for temperatures up to 400 F with a grazing flow up to Mach 0.8. Measurements of impedance, DC flow resistance, and in the flow rig cases, impact of the liner on boundary layer profiles are documented. In addition to liner rig tests, a limited number of tests were made on liners installed in a mixer-Ejector nozzle to confirm the performance of the liner prediction in an installed configuration.

  13. Effect of fan outlet guide vane on the acoustic treatment design in aeroengine nacelle

    NASA Astrophysics Data System (ADS)

    Sun, X.; Yang, Z.; Wang, X.

    2007-04-01

    The main objective of this study is to clarify the effect of the outlet guide vane (OGV) on the acoustic treatment design in aeroengine nacelle, which received less attention previously. A model of sound propagation through a lining section and a blade row is developed to investigate the interaction between sound sources of blade rows and liners in a channel of parallel walls containing uniform mean flow. The present method makes it possible to evaluate the performance of liner while a blade row is inserted in the channel and the sound attenuation in a duct with both liner section and cascade. Various numerical results show that the effect of the cascade may have diverse effects on sound attenuation of the liner under different conditions, but the existence of the OGV always enhances the total sound attenuation in the duct due to energy dissipation caused by vortex shedding from the tailing edge of the OGV. To pursue a better design of acoustic liner in aeroengine nacelle, it is thus necessary to include the effect of OGV on the sound attenuation.

  14. Comparison between design and installed acoustic characteristics of NASA Lewis 9- by 15-foot low-speed wind tunnel acoustic treatment

    NASA Technical Reports Server (NTRS)

    Dahl, Milo D.; Woodward, Richard P.

    1990-01-01

    The test section of the NASA Lewis 9- by 15-Foot Low-Speed Wind Tunnel was acoustically treated to allow the measurement of sound under simulated free-field conditions. The treatment was designed for high sound absorption at frequencies above 250 Hz and for withstanding the environmental conditions in the test section. In order to achieve the design requirements, a fibrous, bulk-absorber material was packed into removable panel sections. Each section was divided into two equal-depth layers packed with material to different bulk densities. The lower density was next to the facing of the treatment. The facing consisted of a perforated plate and screening material layered together. Sample tests for normal-incidence acoustic absorption were also conducted in an impedance tube to provide data to aid in the treatment design. Tests with no airflow, involving the measurement of the absorptive properties of the treatment installed in the 9- by 15-foot wind tunnel test section, combined the use of time-delay spectrometry with a previously established free-field measurement method. This new application of time-delay spectrometry enabled these free-field measurements to be made in nonanechoic conditions. The results showed that the installed acoustic treatment had absorption coefficients greater than 0.95 over the frequency range 250 Hz to 4 kHz. The measurements in the wind tunnel were in good agreement with both the analytical prediction and the impedance tube test data.

  15. Post Treatment of Acoustic Neuroma

    MedlinePlus

    Home What is an AN What is an Acoustic Neuroma? Identifying an AN Symptoms Acoustic Neuroma Keywords Educational Video Pre-Treatment Treatment Options Summary Treatment Options Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions ...

  16. Acoustic Treatment Design Scaling Methods. Volume 5; Analytical and Experimental Data Correlation

    NASA Technical Reports Server (NTRS)

    Chien, W. E.; Kraft, R. E.; Syed, A. A.

    1999-01-01

    The primary purpose of the study presented in this volume is to present the results and data analysis of in-duct transmission loss measurements. Transmission loss testing was performed on full-scale, 1/2-scale, and 115-scale treatment panel samples. The objective of the study was to compare predicted and measured transmission loss for full-scale and subscale panels in an attempt to evaluate the variations in suppression between full- and subscale panels which were ostensibly of equivalent design. Generally, the results indicated an unsatisfactory agreement between measurement and prediction, even for full-scale. This was attributable to difficulties encountered in obtaining sufficiently accurate test results, even with extraordinary care in calibrating the instrumentation and performing the test. Test difficulties precluded the ability to make measurements at frequencies high enough to be representative of subscale liners. It is concluded that transmission loss measurements without ducts and data acquisition facilities specifically designed to operate with the precision and complexity required for high subscale frequency ranges are inadequate for evaluation of subscale treatment effects.

  17. Conceptual architectural/acoustical design

    NASA Astrophysics Data System (ADS)

    Marshall, A. Harold

    2004-05-01

    The thinking which characterizes acoustics as a branch of physics and engineering has difficulty with the architectural design process-the process that generates a room concept in the imagination and experience of the architect. The architect has learned to ``sense'' the visual properties of a room as the design develops in the interaction between mind and media. Phrases such as ``wanting to be'' express the architectural intention but too often such intentions are dismissed as arbitrary; acoustics may then be about fixing the design with acoustical add-ons. Occasionally there is a true meeting of minds-a creative and receptive architect and an acoustician able to communicate at the level of the architectural intention. There is evidently an auditory dimension of wanting to be which is one with the visual. This paper explores the idea in several examples and concludes with suggestions for the training of acousticians.

  18. Noise testing of an advanced design propeller in the Boeing transonic wind tunnel with and without test section acoustic treatment

    NASA Astrophysics Data System (ADS)

    Glover, B. M., Jr.; Plunkett, E. I.; Simcox, C. D.

    1984-10-01

    Noise tests using the NASA SR-6 advanced design propeller in the Boeing Transonic Wind Tunnel have recently been completed. Measurements were taken both with and without an acoustically treated test section. A wide range of helical tip speeds and power loadings were explored. Noise test techniques, previously not applied to advanced design propeller testing, have shown results indicating an increased level of confidence in the measured signatures. Typical results are presented along with recommendations for future noise tests and elementary empirical prediction methods for the SR-6.

  19. Acoustical Design of Music Education Facilities.

    ERIC Educational Resources Information Center

    McCue, Edward, Ed.; Talaske, Richard H., Ed.

    This publication provides essays on the acoustical design of music education facilities and reproductions of posters describing 50 projects presented at the 117th Meeting of the Acoustical Society of American held in Syracuse, New York in May 1989. Essays are as follows: "Introduction to the Design Process" (Richard Talaske); "The…

  20. Design Report for Low Power Acoustic Detector

    DTIC Science & Technology

    2013-08-01

    the hardware design, target detection algorithm design in both MATLAB and VHDL , and typical performance results. 15. SUBJECT TERMS Acoustic low...diagram. .......................................................................................................3 Figure 4. HED VHDL block diagram...6 Figure 5. DCD VHDL block diagram

  1. Quiet, Clean, Short-Haul Experimental Engine (QCSEE) Over-The-Wing (OTW) engine acoustic design

    NASA Technical Reports Server (NTRS)

    Sowers, H. D.; Coward, W. E.

    1978-01-01

    The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the over-the-wing (OTW) nacelle acoustic treatment design are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the OTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment.

  2. Quiet, Clean, Short-Haul, Experimental Engine (QCSEE) Under-The-Wing (UTW) engine acoustic design

    NASA Technical Reports Server (NTRS)

    Sowers, H. D.; Coward, W. E.

    1978-01-01

    The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the under-the-wing (UTW) engine boilerplate and composite nacelle acoustic treatment designs are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the UTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment.

  3. Graphical Acoustic Liner Design and Analysis Tool

    NASA Technical Reports Server (NTRS)

    Howerton, Brian M. (Inventor); Jones, Michael G. (Inventor)

    2016-01-01

    An interactive liner design and impedance modeling tool comprises software utilized to design acoustic liners for use in constrained spaces, both regularly and irregularly shaped. A graphical user interface allows the acoustic channel geometry to be drawn in a liner volume while the surface impedance calculations are updated and displayed in real-time. A one-dimensional transmission line model may be used as the basis for the impedance calculations.

  4. Design of a programmable active acoustics metamaterial

    NASA Astrophysics Data System (ADS)

    Smoker, Jason J.

    Metamaterials are artificial materials engineered to provide properties which may not be readily available in nature. The development of such class of materials constitutes a new area of research that has grown significantly over the past decade. Acoustic metamaterials, specifically, are even more novel than their electromagnetic counterparts arising only in the latter half of the decade. Acoustic metamaterials provide a new tool in controlling the propagation of pressure waves. However, physical design and frequency tuning, is still a large obstacle when creating a new acoustic metamaterial. This dissertation describes active and programmable design for acoustic metamaterials which allows the same basic physical design principles to be used for a variety of application. With cloaking technology being of a great interest to the US Navy, the proposed design approach would enable the development of a metamaterial with spatially changing effective parameters while retaining a uniform physical design features. The effective parameters would be controlled by tuning smart actuators embedded inside the metamaterial structure. Since this design is based on dynamic effective parameters that can be electrically controlled, material property ranges of several orders of magnitude could potentially be achieved without changing any physical parameters. With such unique capabilities, physically realizable acoustic cloaks can be achieved and objects treated with these active metamaterials can become acoustically invisible.

  5. The acoustic design of outside broadcast vehicles

    NASA Astrophysics Data System (ADS)

    Taylor, E. W.

    1984-05-01

    A review is given of the acoustic design of outside broadcast vehicles in terms of the constraints implicit in the use of road vehicles. A new design of vehicle wall construction is described, the provision of sound absorbing material suitable for use in small enclosures is discussed, and particular factors involved in utilizing large (articulated) vehicles are mentioned. As an illustration, an account is given of the acoustic design of the BBC's Digital Control Vehicle: priority was given, in this vehicle, to the provision of the best possible environment for sound monitoring and control.

  6. Student design projects in applied acoustics.

    PubMed

    Bös, Joachim; Moritz, Karsten; Skowronek, Adam; Thyes, Christian; Tschesche, Johannes; Hanselka, Holger

    2012-03-01

    This paper describes a series of student projects which are intended to complement theoretical education in acoustics and engineering noise control with practical experience. The projects are also intended to enhance the students' ability to work in a team, to manage a project, and to present their results. The projects are carried out in close cooperation with industrial partners so that the students can get a taste of the professional life of noise control engineers. The organization of such a project, its execution, and some of the results from the most recent student project are presented as a demonstrative example. This latest project involved the creation of noise maps of a production hall, the acoustic analysis of a packaging machine, and the acoustic analysis of a spiral vibratory conveyor. Upon completion of the analysis, students then designed, applied, and verified some simple preliminary noise reduction measures to demonstrate the potential of these techniques.

  7. ACOUSTICS IN ARCHITECTURAL DESIGN, AN ANNOTATED BIBLIOGRAPHY ON ARCHITECTURAL ACOUSTICS.

    ERIC Educational Resources Information Center

    DOELLE, LESLIE L.

    THE PURPOSE OF THIS ANNOTATED BIBLIOGRAPHY ON ARCHITECTURAL ACOUSTICS WAS--(1) TO COMPILE A CLASSIFIED BIBLIOGRAPHY, INCLUDING MOST OF THOSE PUBLICATIONS ON ARCHITECTURAL ACOUSTICS, PUBLISHED IN ENGLISH, FRENCH, AND GERMAN WHICH CAN SUPPLY A USEFUL AND UP-TO-DATE SOURCE OF INFORMATION FOR THOSE ENCOUNTERING ANY ARCHITECTURAL-ACOUSTIC DESIGN…

  8. Turbomachinery design and tonal acoustics computations

    NASA Technical Reports Server (NTRS)

    Rangwalla, Akil A.

    1995-01-01

    The objective of this research was two-fold. The first objective was to complete the three-dimensional unsteady calculations of the flow through a new transonic turbine and study the effects of secondary flows due to the hub and casing, tip clearance vortices, and the inherent three-dimensional mixing of the flow. It should be noted that this turbine was and is still in the design phase and the results of the calculations have formed an integral part of the design process. The second objective of this proposal was to evaluate the capability of rotor-stator interaction codes to calculate tonal acoustics.

  9. Bifunctional acoustic metamaterial lens designed with coordinate transformation

    NASA Astrophysics Data System (ADS)

    Zhu, Rongrong; Ma, Chu; Zheng, Bin; Musa, Muhyiddeen Yahya; Jing, Liqiao; Yang, Yihao; Wang, Huaping; Dehdashti, Shahram; Fang, Nicholas X.; Chen, Hongsheng

    2017-03-01

    We propose a method to design bifunctional acoustic lens using acoustic metamaterials that possess separate functions at different directions. The proposed bifunctional acoustic lens can be implemented in practice with subwavelength unit cells exhibiting effective anisotropic parameters. With this methodology, we experimentally demonstrate an acoustic Luneburg-fisheye lens at operational frequencies from 6300 Hz to 7300 Hz. Additionally, a bifunctional acoustic square lens is proposed with different focal lengths for multi directions. This method paves the way to manipulating acoustic energy flows with functional lenses.

  10. Combining COMSOL modeling with acoustic pressure maps to design sono-reactors.

    PubMed

    Wei, Zongsu; Weavers, Linda K

    2016-07-01

    Scaled-up and economically viable sonochemical systems are critical for increased use of ultrasound in environmental and chemical processing applications. In this study, computational simulations and acoustic pressure maps were used to design a larger-scale sono-reactor containing a multi-stepped ultrasonic horn. Simulations in COMSOL Multiphysics showed ultrasonic waves emitted from the horn neck and tip, generating multiple regions of high acoustic pressure. The volume of these regions surrounding the horn neck were larger compared with those below the horn tip. The simulated acoustic field was verified by acoustic pressure contour maps generated from hydrophone measurements in a plexiglass box filled with water. These acoustic pressure contour maps revealed an asymmetric and discrete distribution of acoustic pressure due to acoustic cavitation, wave interaction, and water movement by ultrasonic irradiation. The acoustic pressure contour maps were consistent with simulation results in terms of the effective scale of cavitation zones (∼ 10 cm and <5 cm above and below horn tip, respectively). With the mapped acoustic field and identified cavitation location, a cylindrically-shaped sono-reactor with a conical bottom was designed to evaluate the treatment capacity (∼ 5 L) for the multi-stepped horn using COMSOL simulations. In this study, verification of simulation results with experiments demonstrates that coupling of COMSOL simulations with hydrophone measurements is a simple, effective and reliable scientific method to evaluate reactor designs of ultrasonic systems.

  11. Acoustic Wave Treatment For Cellulite—A New Approach

    NASA Astrophysics Data System (ADS)

    Russe-Wilflingseder, Katharina; Russe, Elisabeth

    2010-05-01

    Background and Objectives: Cellulite is a biological caused modification of the female connective tissue. In extracorporeal shockwave therapy (ESWT) pulses are penetrating into the tissue without causing a thermal effect or micro lesions, but leading to a stimulation of tissue metabolism and blood circulation, inducing a natural repair process with cell activation and stem cells proliferation. Recently ESWT treatment showed evidence of remodelling collagen within the dermis and of stimulating microcirculation in fatty tissue. Study Design and Methods: The study was designed to assess acoustic wave treatment for cellulite by comparison treated vs. untreated side (upper-leg and buttock). Each individual served as its own control. 11 females with a BMI less then 30 and an age over 18 years were included. 6 treatments were given weekly with radial acoustic waves. Documentation was done before and 1, 4, 12 weeks after last treatment by standardized photo documentation, relaxed and with muscle contraction, measurement of body weight and circumference of the thigh, pinch test, and evaluation of hormonal status and lifestyle. The efficacy of AWT/EPAT was evaluated before and 1, 4, 12 weeks after last treatment. Patients rated the improvement of cellulite, overall satisfaction and acceptance. The therapist assessed improvement of cellulite, side effects and photo documentation treated vs. untreated side, before vs. after treatment. The blinded investigator evaluated the results using photo documentation right vs. left leg, before vs. after treatment in a frontal, lateral and dorsal view, relaxed and with muscle contraction. Results: The improvement of cellulite at the treated side was rated by patients with 27,3% at week 4 and 12, by the therapist with 34,1% at week 4 and 31,2% at week 12 after the last treatment The blinded investigator could verify an improvement of cellulite in an increasing number of patients with increasing time interval after treatment. No side

  12. The Development of the Acoustic Design of NASA Glenn Research Center's New Reverberant Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Mark E.; Hozman, Aron D.; McNelis, Anne M.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC s Plum Brook Station in Sandusky, Ohio. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA s space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 ft3 in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world s known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada s acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent on-going construction.

  13. The Development of the Acoustic Design of NASA Glenn Research Center's New Reverberant Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Mark E.; Hozman, Aron D.; McNelis, Anne M.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC's Plum Brook Station in Sandusky, Ohio, USA. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA s space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 ft3 in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world s known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada s acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama, USA. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent on-going construction.

  14. Case study of restaurant successfully designed, constructed, and operated for excellent dining acoustics

    NASA Astrophysics Data System (ADS)

    Bollard, Paul; Des Jardins, Stephen

    2005-09-01

    Prior to the construction of La Provence Restaurant in Roseville, California in 2004, the owner, Stephen Des Jardins, traveled with his cook, architect, and engineer to the Provence Region of France to study the cuisine, architecture, and acoustics of the local restaurants. This information was incorporated into the design, construction, and operation of his restaurant, with acoustical design assistance provided by the author, Paul Bollard. The result of the owner's painstaking attention to detail is a restaurant which has received very positive reviews for its architecture, quality of food, service, and acoustic ambience. This paper documents the measures included in the construction of the restaurant to ensure that the building acoustics enhance the dining experience, rather than detract from it. Photographs of acoustic treatments are included, as are reverberation time (RT60) test results and ambient noise level measurement results.

  15. Wavenumber transform analysis for acoustic black hole design.

    PubMed

    Feurtado, Philip A; Conlon, Stephen C

    2016-07-01

    Acoustic black holes (ABHs) are effective, passive, lightweight vibration absorbers that have been developed and shown to effectively reduce the structural vibration and radiated sound of beam and plate structures. ABHs employ a local thickness change that reduces the speed of bending waves and increases the transverse vibration amplitude. The vibrational energy can then be effectively focused and dissipated by material losses or through conventional viscoelastic damping treatments. In this work, the measured vibratory response of embedded ABH plates was transformed into the wavenumber domain in order to investigate the use of wavenumber analysis for characterizing, designing, and optimizing practical ABH systems. The results showed that wavenumber transform analysis can be used to simultaneously visualize multiple aspects of ABH performance including changes in bending wave speed, transverse vibration amplitude, and energy dissipation. The analysis was also used to investigate the structural acoustic coupling of the ABH system and determine the radiation efficiency of the embedded ABH plates compared to a uniform plate. The results demonstrated that the ABH effect results in acoustic decoupling as well as vibration reduction. The wavenumber transform based methods and results will be useful for implementing ABHs into real world structures.

  16. Acoustic attenuation design requirements established through EPNL parametric trades

    NASA Technical Reports Server (NTRS)

    Veldman, H. F.

    1972-01-01

    An optimization procedure for the provision of an acoustic lining configuration that is balanced with respect to engine performance losses and lining attenuation characteristics was established using a method which determined acoustic attenuation design requirements through parametric trade studies using the subjective noise unit of effective perceived noise level (EPNL).

  17. Design and demonstration of broadband thin planar diffractive acoustic lenses

    SciTech Connect

    Wang, Wenqi; Xie, Yangbo; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A.

    2014-09-08

    We present here two diffractive acoustic lenses with subwavelength thickness, planar profile, and broad operation bandwidth. Tapered labyrinthine unit cells with their inherently broadband effective material properties are exploited in our design. Both the measured and the simulated results are showcased to demonstrate the lensing effect over more than 40% of the central frequency. The focusing of a propagating Gaussian modulated sinusoidal pulse is also demonstrated. This work paves the way for designing diffractive acoustic lenses and more generalized phase engineering diffractive elements with labyrinthine acoustic metamaterials.

  18. A broadband polygonal cloak for acoustic wave designed with linear coordinate transformation.

    PubMed

    Zhu, Rongrong; Zheng, Bin; Ma, Chu; Xu, Jun; Fang, Nicholas; Chen, Hongsheng

    2016-07-01

    Previous acoustic cloaks designed with transformation acoustics always involve inhomogeneous material. In this paper, a design of acoustic polygonal cloak is proposed using linear polygonal transformation method. The designed acoustic polygonal cloak has homogeneous and anisotropic parameters, which is much easier to realize in practice. Furthermore, a possible acoustic metamaterial structure to realize the cloak is proposed. Simulation results on the real structure show that the metamaterial acoustic cloak is effective to reduce the scattering of the object.

  19. Ducted fan acoustic radiation including the effects of nonuniform mean flow and acoustic treatment

    NASA Technical Reports Server (NTRS)

    Eversman, Walter; Roy, Indranil Danda

    1993-01-01

    Forward and aft acoustic propagation and radiation from a ducted fan is modeled using a finite element discretization of the acoustic field equations. The fan noise source is introduced as equivalent body forces representing distributed blade loading. The flow in and around the nacelle is assumed to be nonuniform, reflecting the effects of forward flight and flow into the inlet. Refraction due to the fan exit jet shear layer is not represented. Acoustic treatment on the inlet and exhaust duct surfaces provides a mechanism for attenuation. In a region enclosing the fan a pressure formulation is used with the assumption of locally uniform flow. Away from the fan a velocity potential formulation is used and the flow is assumed nonuniform but irrotational. A procedure is developed for matching the two regions by making use of local duct modal amplitudes as transition state variables and determining the amplitudes by enforcing natural boundary conditions at the interface between adjacent regions in which pressure and velocity potential are used. Simple models of rotor alone and rotor/exit guide vane generated noise are used to demonstrate the calculation of the radiated acoustic field and to show the effect of acoustic treatment. The model has been used to assess the success of four techniques for acoustic lining optimization in reducing far field noise.

  20. Acoustic and vibration response of a structure with added noise control treatment under various excitations.

    PubMed

    Rhazi, Dilal; Atalla, Noureddine

    2014-02-01

    The evaluation of the acoustic performance of noise control treatments is of great importance in many engineering applications, e.g., aircraft, automotive, and building acoustics applications. Numerical methods such as finite- and boundary elements allow for the study of complex structures with added noise control treatment. However, these methods are computationally expensive when used for complex structures. At an early stage of the acoustic trim design process, many industries look for simple and easy to use tools that provide sufficient physical insight that can help to formulate design criteria. The paper presents a simple and tractable approach for the acoustic design of noise control treatments. It presents and compares two transfer matrix-based methods to investigate the vibroacoustic behavior of noise control treatments. The first is based on a modal approach, while the second is based on wave-number space decomposition. In addition to the classical rain-on-the-roof and diffuse acoustic field excitations, the paper also addresses turbulent boundary layer and point source (monopole) excitations. Various examples are presented and compared to a finite element calculation to validate the methodology and to confirm its relevance along with its limitations.

  1. Ocean Acoustic Tomography Mooring Design Study.

    DTIC Science & Technology

    1982-04-01

    Figure 5 A- 13 APPENDIX B Power Systems for the Long-Range Acoustic Transmitter STRAWMAN #1 Lithium Primary Battery Lithium Thionyl Chloride ...buoyancy provided by a syntactic foam sphere. - LRT and the top buoyancy at the same depth. - Lithium primary battery placed with LRT. - Tension member...much less pressure). 4. Same as 1. except: - Lithium primary battery placed upon the anchor. - Electromechanical cable (also the tension member

  2. Acoustical design of the new Cathay Pacific first class lounge

    NASA Astrophysics Data System (ADS)

    Hong, Westwood K. W.

    Cathay Pacific Airways' requirement of a first class lounge for attracting the high-yield passenger market to Hong Kong presented a special challenge for the Acoustical consultant. The 500-seating lounge covers more than 2000 square meters and is claimed by Cathay to be the biggest in Asia for its first class passengers. Arup acoustics was required to design a space that provided a quiet and relaxed environment for the Commercial Important Persons after a 16 to 17-hour flight. Arup Acoustics has designed the acoustics of the Lounge in meeting a stringent low noise specification requested by the user. The design work gave a comprehensive service both to support the lead consultant Ova Arup & Partners in controlling the external aircraft noise and internal noise and to assist the architect and interior designer in providing an excellent acoustical atmosphere for the passengers to rest while waiting for an onward connection. This paper will discuss the design of the lightweight roof and special double glazing system, featured by a 20-mm-thick laminated glass for the outer pane and a 600 to 1000-mm air gap to combat aircraft noise at the Hong Kong International Airport.

  3. Acoustical pipe lagging systems design and performance

    SciTech Connect

    Stevens, R.D.; Chapnik, B.V.; Howe, B.

    1998-10-30

    HGC Engineering was retained by the PRC International at the American Gas Association, to undertake a study of acoustical pipe lagging systems. The study included gathering input from PRCI member companies regarding their concerns and their established material specifications for lagging systems; conducting a comprehensive acoustical measurement program; using the measured results in conjunction with computer modeling to identify optimal lagging configurations; and developing material specifications for several standardized lagging systems for use by PRCI member companies. For all the lagging configurations, the measurement and modeling results showed amplification of sound at frequencies less than about 315 Hz. This result is a well known phenomenon, widely discussed the published acoustical literature, which means that pipe lagging is only effective for controlling higher frequencies noise (above about 500 Hz). Fortunately, in many gas piping applications, it is this higher frequency range that is of concern. The measurement and modeling results further showed that the high frequency performance of a lagging system is dependent primarily on having sufficient jacket mass and insulation thickness. The performance can be improved using an intermediate mass loaded barrier layer.

  4. 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.

  5. Design of an acoustic metamaterial lens using genetic algorithms.

    PubMed

    Li, Dennis; Zigoneanu, Lucian; Popa, Bogdan-Ioan; Cummer, Steven A

    2012-10-01

    The present work demonstrates a genetic algorithm approach to optimizing the effective material parameters of an acoustic metamaterial. The target device is an acoustic gradient index (GRIN) lens in air, which ideally possesses a maximized index of refraction, minimized frequency dependence of the material properties, and minimized acoustic impedance mismatch. Applying this algorithm results in complex designs with certain common features, and effective material properties that are better than those present in previous designs. After modifying the optimized unit cell designs to make them suitable for fabrication, a two-dimensional lens was built and experimentally tested. Its performance was in good agreement with simulations. Overall, the optimization approach was able to improve the refractive index but at the cost of increased frequency dependence. The optimal solutions found by the algorithm provide a numerical description of how the material parameters compete with one another and thus describes the level of performance achievable in the GRIN lens.

  6. The acoustic design of the Centro Nacional de las Artes in Mexico City

    NASA Astrophysics Data System (ADS)

    Cooper, Rusell

    2002-11-01

    In this paper the acoustic design of the separate buildings housing the school of music, school of drama, and school of dance that opened in 1996 will be described. Spaces that JHA designed included practice rooms, studios, rehearsal rooms, black box, and concert hall. Details of room acoustic treatments, sound isolation measures, and venturi air flow will be illustrated. An overview of the entire project will also include the 500 seat multipurpose theater (with variable absorption systems) and the Alla Magna. Differences between the American and Mexican styles of consulting, importing of materials, installation, and commissioning will also be discussed.

  7. Acoustic Treatment Design Scaling Methods. Volume 4; Numerical Simulation of the Nonlinear Acoustic Impedance of a Perforated Plate Single-Degree-of-Freedom Resonator Using a Time-Domain Finite Difference Method

    NASA Technical Reports Server (NTRS)

    Kraft, R. E.

    1999-01-01

    Single-degree-of-freedom resonators consisting of honeycomb cells covered by perforated facesheets are widely used as acoustic noise suppression liners in aircraft engine ducts. The acoustic resistance and mass reactance of such liners are known to vary with the intensity of the sound incident upon the panel. Since the pressure drop across a perforated liner facesheet increases quadratically with the flow velocity through the facesheet, this is known as the nonlinear resistance effect. In the past, two different empirical frequency domain models have been used to predict the Sound Pressure Level effect of the incident wave on the perforated liner impedance, one that uses the incident particle velocity in isolated narrowbands, and one that models the particle velocity as the overall velocity. In the absence of grazing flow, neither frequency domain model is entirely accurate in predicting the nonlinear effect that is measured for typical perforated sheets. The time domain model is developed in an attempt to understand and improve the model for the effect of spectral shape and amplitude of multi-frequency incident sound pressure on the liner impedance. A computer code for the time-domain finite difference model is developed and predictions using the models are compared to current frequency-domain models.

  8. Lightweight acoustic treatments for aerospace applications

    NASA Astrophysics Data System (ADS)

    Naify, Christina Jeanne

    2011-12-01

    Increase in the use of composites for aerospace applications has the benefit of decreased structural weight, but at the cost of decreased acoustic performance. Stiff, lightweight structures (such as composites) are traditionally not ideal for acoustic insulation applications because of high transmission loss at low frequencies. A need has thus arisen for effective sound insulation materials for aerospace and automotive applications with low weight addition. Current approaches, such as the addition of mass law dominated materials (foams) also perform poorly when scaled to small thickness and low density. In this dissertation, methods which reduce sound transmission without adding significant weight are investigated. The methods presented are intended to be integrated into currently used lightweight structures such as honeycomb sandwich panels and to cover a wide range of frequencies. Layering gasses of differing acoustic impedances on a panel substantially reduced the amount of sound energy transmitted through the panel with respect to the panel alone or an equivalent-thickness single species gas layer. The additional transmission loss derives from successive impedance mismatches at the interfaces between gas layers and the resulting inefficient energy transfer. Attachment of additional gas layers increased the transmission loss (TL) by as much as 17 dB at high (>1 kHz) frequencies. The location and ordering of the gasses with respect to the panel were important factors in determining the magnitude of the total TL. Theoretical analysis using a transfer matrix method was used to calculate the frequency dependence of sound transmission for the different configurations tested. The method accurately predicted the relative increases in TL observed with the addition of different gas layer configurations. To address low-frequency sound insulation, membrane-type locally resonant acoustic materials (LRAM) were fabricated, characterized, and analyzed to understand their

  9. International Space Station Crew Quarters Ventilation and Acoustic Design Implementation

    NASA Technical Reports Server (NTRS)

    Broyan, James L., Jr.; Cady, Scott M; Welsh, David A.

    2010-01-01

    The International Space Station (ISS) United States Operational Segment has four permanent rack sized ISS Crew Quarters (CQs) providing a private crew member space. The CQs use Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air-from the ISS Common Cabin Air Assembly (CCAA) or the ISS fluid cooling loop. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crew member's head position and reduce acoustic exposure. The CQ ventilation ducts are conduits to the louder Node 2 cabin aisle way which required significant acoustic mitigation controls. The CQ interior needs to be below noise criteria curve 40 (NC-40). The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. Each CQ required 13% of its total volume and approximately 6% of its total mass to reduce acoustic noise. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

  10. Fluid mechanics, acoustics, and design of turbomachinery, part 2

    NASA Technical Reports Server (NTRS)

    Lakshminarayana, B. (Editor); Britsch, W. R. (Editor); Gearhart, W. S. (Editor)

    1974-01-01

    A conference was conducted to investigate various parameters involved in the design of turbomachinery. The acoustic properties of compressor rotors at subsonic speeds are described to show the sources of sound in fluid flows and sound radiation from the rotors. The design criteria for turbomachinery are examined to show impeller design methods, transonic compressor technology, and blade selection for an axial flow compressor. Specific applications of turbomachinery used as pumps for aerospace applications and turbomachinery for marine propulsion are described.

  11. Transducer Design Experiments for Ground-Penetrating Acoustic Systems

    DTIC Science & Technology

    2007-11-02

    subsurface imaging experiments have utilized a source (Tx) and receiver (Rx) configuration in which signals produced by a transmitter at the soil surface...development in the field of acoustic subsurface imaging are as follows. First, a transmitter designed to minimize the emission of surface waves, while

  12. Design and performance analysis of digital acoustic underwater telemetry system

    NASA Astrophysics Data System (ADS)

    Catipovic, J. A.; Baggeroer, A. B.; Vonderheydt, K.; Koelsch, D. E.

    1985-11-01

    The work discusses the design and performance characteristics of a Digital Acoustic Telemetry System (DATS) which incorporates the current state-of-the-art technology and is capable of reliable data transmission at rates useful to a wide range of ocean exploration and development gear.

  13. Acoustical Considerations in Planning and Design of Library Facilities.

    ERIC Educational Resources Information Center

    Wrightson, Denelle; Wrightson, John M.

    1999-01-01

    Discusses acoustical demands in public libraries to consider during the design and construction process of new or renovated library space. Topics include intrusive noises; overly reverberant spaces; lack of speech privacy; sound transmission class; noise criteria; reverberation time and noise reduction coefficient; space planning; sound systems;…

  14. Thermo-acoustic fatigue design for hypersonic vehicle skin panels

    NASA Astrophysics Data System (ADS)

    Wentz, Kenneth R.; Blevins, Robert D.; Holehouse, Ian

    1994-09-01

    Thermo-vibro-acoustic analysis and test of skin panels for airbreathing hypersonic vehicles is made for a generic vehicle and trajectory. Aerothermal analysis shows that impingement of the bow shock wave on the vehicle and engine noise produce high fluctuating pressures and local heat fluxes. Maximum temperatures will exceed 2700 F (1480 C) at the top of the ascent trajectory and engine sound levels will exceed 170 dB at takeoff. As a result, loads due to engine acoustics and shock impingement dominate the design of many transatmospheric vehicle skin panels.

  15. Design, characterization and modeling of biobased acoustic foams

    NASA Astrophysics Data System (ADS)

    Ghaffari Mosanenzadeh, Shahrzad

    Polymeric open cell foams are widely used as sound absorbers in sectors such as automobile, aerospace, transportation and building industries, yet there is a need to improve sound absorption of these foams through understanding the relation between cell morphology and acoustic properties of porous material. Due to complicated microscopic structure of open cell foams, investigating the relation between foam morphology and acoustic properties is rather intricate and still an open problem in the field. The focus of this research is to design and develop biobased open cell foams for acoustic applications to replace conventional petrochemical based foams as well as investigating the link between cell morphology and macroscopic properties of open cell porous structures. To achieve these objectives, two industrially produced biomaterials, polylactide (PLA) and polyhydroxyalkanoate (PHA) and their composites were examined and highly porous biobased foams were fabricated by particulate leaching and compression molding. Acoustic absorption capability of these foams was enhanced utilizing the effect of co-continuous blends to form a bimodal porous structure. To tailor mechanical and acoustic properties of biobased foams, blends of PLA and PHA were studied to reach the desired mechanical and viscoelastic properties. To enhance acoustic properties of porous medium for having a broad band absorption effect, cell structure must be appropriately graded. Such porous structures with microstructural gradation are called Functionally Graded Materials (FGM). A novel graded foam structure was designed with superior sound absorption to demonstrate the effect of cell arrangement on performance of acoustic fixtures. Acoustic measurements were performed in a two microphone impedance tube and acoustic theory of Johnson-Champoux-Allard was applied to the fabricated foams to determine micro cellular properties such as tortuosity, viscous and thermal lengths from sound absorption impedance tube

  16. Single stage, low noise advanced technology fan. Volume 3: Acoustic design

    NASA Technical Reports Server (NTRS)

    Kazin, S. B.; Mishler, R. B.

    1976-01-01

    The acoustic design for a half-scale fan vehicle, which would have application on an advanced transport aircraft, is described. The single stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec (1,650 ft/sec). The two basic approaches taken in the acoustic design were: (1) minimization of noise at the source, and (2) suppression of the generated noise in the inlet and bypass exhaust duct. Suppression of the generated noise is accomplished in the inlet through use of the hybrid concept (wall acoustic treatment plus airflow acceleration suppression) and in the exhaust duct with extensive acoustic treatment including a splitter. The goal of the design was attainment of twenty effective perceived noise decibels (20 EPNdB) below current Federal Air Regulation noise standards for a full-scale fan at the takeoff, cutback, and approach conditions. Predicted unsuppressed and suppressed fore and aft maximum perceived noise levels indicate that the cutback condition is the most critical with respect to the goal, which is probably unattainable for that condition. This is also true for aft radiated noise in the approach condition.

  17. Computer method for design of acoustic liners for turbofan engines

    NASA Technical Reports Server (NTRS)

    Minner, G. L.; Rice, E. J.

    1976-01-01

    A design package is presented for the specification of acoustic liners for turbofans. An estimate of the noise generation was made based on modifications of existing noise correlations, for which the inputs are basic fan aerodynamic design variables. The method does not predict multiple pure tones. A target attenuation spectrum was calculated which was the difference between the estimated generation spectrum and a flat annoyance-weighted goal attenuated spectrum. The target spectrum was combined with a knowledge of acoustic liner performance as a function of the liner design variables to specify the acoustic design. The liner design method at present is limited to annular duct configurations. The detailed structure of the liner was specified by combining the required impedance (which is a result of the previous step) with a mathematical model relating impedance to the detailed structure. The design procedure was developed for a liner constructed of perforated sheet placed over honeycomb backing cavities. A sample calculation was carried through in order to demonstrate the design procedure, and experimental results presented show good agreement with the calculated results of the method.

  18. Design and demonstration of an underwater acoustic carpet cloak.

    PubMed

    Bi, Yafeng; Jia, Han; Lu, Wenjia; Ji, Peifeng; Yang, Jun

    2017-04-06

    The carpet cloak, which is designed to hide the objects placed on a reflecting surface, has become a topic of considerable interest. Inspired by those theoretical works, the experimental realization of acoustic carpet cloak in air host has been reported. However, due to the difficulty in obtaining the unit cell in reality, the underwater carpet cloak still remains in simulation thus far. Here, we design and fabricate a realizable underwater acoustic carpet cloak. By introducing a scaling factor, the structure of the carpet cloak, which is comprised of layered brass plates, is greatly simplified at the cost of some impedance match. The experimental results demonstrate a good performance of the proposed carpet cloak in a wide frequency range. Our work paves the way for future applications in the practical underwater devices.

  19. Design and acoustic characterization of limited diffraction ultrasonic devices.

    PubMed

    Aulet, A; Núñez, I; Moreno, E; Eiras, J A; Negreira, C A

    2010-05-01

    Limited diffraction ultrasonic transducers are devices that have a large depth of acoustic field without important effects of diffraction, which make them optimal in applications of medical images, among others. This report details how this special type of piezoelectric device was designed by means of a simple technology using three electrodes in the form of concentric rings in both faces of a ferroelectric ceramic disk, which were used to apply a profile of non-homogeneous polarization. Once designed, the radiation fields emitted by these resonators were characterized experimentally by electro-acoustic and acousto-optic techniques and were compared with those emitted by conventional devices. As shown in the experimental characterizations, ultrasonic transducers with optimal properties for use in medical applications such as good collimation of the ultrasound beam, high lateral resolution, as well as little effects of diffraction were obtained.

  20. Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter

    PubMed Central

    Li, Huidong; Deng, Zhiqun Daniel; Yuan, Yong; Carlson, Thomas J.

    2012-01-01

    PZT ceramics have been widely used in underwater acoustic transducers. However, literature available discussing the design parameters of a miniaturized PZT-based low-duty-cycle transmitter is very limited. This paper discusses some of the design parameters—the backing material, driving voltage, PZT material type, power consumption and the transducer length of a miniaturized acoustic fish tag using a PZT tube. Four different types of PZT were evaluated with respect to the source level, energy consumption and bandwidth of the transducer. The effect of the tube length on the source level is discussed. The results demonstrate that ultralow-density closed-cell foam is the best backing material for the PZT tube. The Navy Type VI PZTs provide the best source level with relatively low energy consumption and that a low transducer capacitance is preferred for high efficiency. A 35% reduction in the transducer length results in 2 dB decrease in source level. PMID:23012534

  1. Acoustic design of rotor blades using a genetic algorithm

    NASA Technical Reports Server (NTRS)

    Wells, V. L.; Han, A. Y.; Crossley, W. A.

    1995-01-01

    A genetic algorithm coupled with a simplified acoustic analysis was used to generate low-noise rotor blade designs. The model includes thickness, steady loading and blade-vortex interaction noise estimates. The paper presents solutions for several variations in the fitness function, including thickness noise only, loading noise only, and combinations of the noise types. Preliminary results indicate that the analysis provides reasonable assessments of the noise produced, and that genetic algorithm successfully searches for 'good' designs. The results show that, for a given required thrust coefficient, proper blade design can noticeably reduce the noise produced at some expense to the power requirements.

  2. Design of a Subsurface Moored Acoustic Array in Deep Water

    DTIC Science & Technology

    2007-01-01

    concepts were a culmination of many years design teams past experience with undersea cable structures. Offshore structural analysis software [2] was...concept as a baseline, the complete STAFAC mooring with umbilicals is shown in Fig 8., both in elevation view and plan view. Umbilical cables are...navigation. The umbilicals are attached near the upper portion of the HGMS arrays to be consistent with the associate Southeast Alaska Acoustic

  3. Utilizing numerical techniques in turbofan inlet acoustic suppressor design

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.

    1982-01-01

    Numerical theories in conjunction with previously published analytical results are used to augment current analytical theories in the acoustic design of a turbofan inlet nacelle. In particular, a finite element-integral theory is used to study the effect of the inlet lip radius on the far field radiation pattern and to determine the optimum impedance in an actual engine environment. For some single mode JT15D data, the numerical theory and experiment are found to be in a good agreement.

  4. Acoustic Sensor Network Design for Position Estimation

    DTIC Science & Technology

    2009-05-01

    utility is K(ñ) = ( T∑ t=1 ω̃1,tñt )( T∑ t=1 ω̃2,tñt )ρ . (17) We start by noting that the following is a necessary KKT condition for the op- timal...Analysis]: Optimization —Constrained optimization , convex pro- gramming, integer programming, nonlinear programming; G.3 [Probability and Statistics...subsections describe general multiple-objective optimization , exact integer programming methods to find the “ optimal ” designs, and approximate non

  5. INVITED PAPER: On the interaction of a fan stator and acoustic treatments using the transfer element method

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoyu; Sun, Xiaofeng

    2010-02-01

    In the present investigation, a theoretical model is suggested to study the interaction of a fan stator and acoustic treatments using the transfer element method. Firstly, the solution of an acoustic field caused by a fan stator in an infinite duct is extended to that in a finite domain with all knowns and unknowns on the interface plane. Secondly, the related numerical results for an annular cascade are compared with the data obtained by directly solving an integral equation based on the blade boundary condition, which have good agreement with each other. Finally, more emphasis is placed on studying how a fan stator interacts with both upstream and downstream acoustic treatments. It is found that the interaction has an important influence on sound attenuation. In addition, optimal sound attenuation will depend on the combined design of both acoustic treatment and the fan stator.

  6. Acoustic hemostasis device for automated treatment of bleeding in limbs

    NASA Astrophysics Data System (ADS)

    Sekins, K. Michael; Zeng, Xiaozheng; Barnes, Stephen; Hopple, Jerry; Kook, John; Moreau-Gobard, Romain; Hsu, Stephen; Ahiekpor-Dravi, Alexis; Lee, Chi-Yin; Ramachandran, Suresh; Maleke, Caroline; Eaton, John; Wong, Keith; Keneman, Scott

    2012-10-01

    A research prototype automated image-guided acoustic hemostasis system for treatment of deep bleeding was developed and tested in limb phantoms. The system incorporated a flexible, conformal acoustic applicator cuff. Electronically steered and focused therapeutic arrays (Tx) populated the cuff to enable dosing from multiple Tx's simultaneously. Similarly, multiple imaging arrays (Ix) were deployed on the cuff to enable 3D compounded images for targeting and treatment monitoring. To affect a lightweight cuff, highly integrated Tx electrical circuitry was implemented, fabric and lightweight structural materials were used, and components were minimized. Novel cuff and Ix and Tx mechanical registration approaches were used to insure targeting accuracy. Two-step automation was implemented: 1) targeting (3D image volume acquisition and stitching, Power and Pulsed Wave Doppler automated bleeder detection, identification of bone, followed by closed-loop iterative Tx beam targeting), and 2) automated dosing (auto-selection of arrays and Tx dosing parameters, power initiation and then monitoring by acoustic thermometry for power shut-off). In final testing the device automatically detected 65% of all bleeders (with various bleeder flow rates). Accurate targeting was achieved in HIFU phantoms with end-dose (30 sec) temperature rise reaching the desired 33-58°C. Automated closed-loop targeting and treatment was demonstrated in separate phantoms.

  7. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors.

    PubMed

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-06-10

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L).

  8. Design and manufacturing of scanning probe acoustic microscope test phantom

    NASA Astrophysics Data System (ADS)

    Chen, Xiaohui; Fang, Xiaoyue; Song, Jitao; Ding, Mingyue

    2015-03-01

    Acquiring nondestructive internal structures acoustic image as well as the morphology images using scanning probe acoustic microscope (SPAM) is a challenge and no known metrology tools to identify the ultrasonic internal resolution and detectable depth of SPAM in a nondestructive way. Monitoring these defects necessitates the identification of their technical parameters of SPAM. In this paper, the specific materials (test phantoms) were designed and processed so that the ultrasound internal resolution of SPAM in nondestructive imaging of the embedded or buried substructures as well as the morphology images were measured. Experimental results demonstrated the successful identification of embedded or buried defects under the test phantom with the resolution of 50nm for SPAM as well as the detectable depth of more than 100μm.

  9. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors

    PubMed Central

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-01-01

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L). PMID:27294937

  10. Characterization and Design of Spiral Frequency Steerable Acoustic Transducers

    NASA Astrophysics Data System (ADS)

    Repale, Rohan

    Structural Health Monitoring (SHM) is an emerging research area devoted to improving the safety and maintainability of civil structures. Guided wave structural testing method is an effective approach used for SHM of plate-like structures using piezoelectric transducers. These transducers are attached to the surface of the structure and are capable of sensing its health by using surface waves. Transducers with beam steering i.e. electronic scanning capabilities can perform surface interrogation with higher precision and ease. A frequency steerable acoustic transducer (FSAT) is capable of beam steering and directional surface wave sensing to detect and localize damage in structures. The objective of this research is to further explore the possibilities of FSAT technology by designing and testing new FSAT designs. The beam steering capability of FSAT can be controlled by manipulating its design parameters. These design parameters therefore play a significant role in FSAT's performance. Studying the design parameters and documenting the performance improvements based on parameter variation is the primary goal of this research. Design and characterization of spiral FSAT was performed and results were simulated. Array FSAT documented results were validated. Modified designs were modeled based on design parameter variations. Characterization of these designs was done and their performance was recorded. Plate simulation results confirm direct relationship between design parameters and beam steering. A set of guidelines for future designs was also proposed. Two designs developed based on the set guidelines were sent to our collaborator Genziko Inc. for fabrication.

  11. Design and optimization of membrane-type acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Blevins, Matthew Grant

    One of the most common problems in noise control is the attenuation of low frequency noise. Typical solutions require barriers with high density and/or thickness. Membrane-type acoustic metamaterials are a novel type of engineered material capable of high low-frequency transmission loss despite their small thickness and light weight. These materials are ideally suited to applications with strict size and weight limitations such as aircraft, automobiles, and buildings. The transmission loss profile can be manipulated by changing the micro-level substructure, stacking multiple unit cells, or by creating multi-celled arrays. To date, analysis has focused primarily on experimental studies in plane-wave tubes and numerical modeling using finite element methods. These methods are inefficient when used for applications that require iterative changes to the structure of the material. To facilitate design and optimization of membrane-type acoustic metamaterials, computationally efficient dynamic models based on the impedance-mobility approach are proposed. Models of a single unit cell in a waveguide and in a baffle, a double layer of unit cells in a waveguide, and an array of unit cells in a baffle are studied. The accuracy of the models and the validity of assumptions used are verified using a finite element method. The remarkable computational efficiency of the impedance-mobility models compared to finite element methods enables implementation in design tools based on a graphical user interface and in optimization schemes. Genetic algorithms are used to optimize the unit cell design for a variety of noise reduction goals, including maximizing transmission loss for broadband, narrow-band, and tonal noise sources. The tools for design and optimization created in this work will enable rapid implementation of membrane-type acoustic metamaterials to solve real-world noise control problems.

  12. Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter

    SciTech Connect

    Li, Huidong; Deng, Zhiqun; Yuan, Yong; Carlson, Thomas J.

    2012-07-02

    The Juvenile Salmon Acoustic Telemetry System (JSATS) project supported by the U.S. Army Corps of Engineers, Portland District, has yielded the smallest acoustic fish tag transmitter commercially available to date. In order to study even smaller fish populations and make the transmitter injectable by needles, the JSATS acoustic micro transmitter needs to be further downsized. As part of the transmitter downsizing effort some of the design parameters of the lead zirconate titanate (PZT) ceramic tube transducer in the transmitter were studied, including the type of PZT, the backing material, the necessary drive voltage, the transmitting bandwidth and the length of the transducer. It was found that, to satisfy the 156-dB source level requirement of JSATS, a square wave with a 10-volt amplitude is required to drive 'soft' PZT transducers. PZT-5H demonstrated the best source level performance. For Navy types I and II, 16 volts or 18 volts were needed. Ethylene-propylene-diene monomer (EPDM) closed-cell foam was found to be the backing material providing the highest source level. The effect of tube length on the source level is also demonstrated in this paper, providing quantitative information for downsizing of small piezoelectric transmitters.

  13. Piezoelectric transducer design for a miniaturized injectable acoustic transmitter

    NASA Astrophysics Data System (ADS)

    Li, H.; Jung, K. W.; Deng, Z. D.

    2015-11-01

    Implantable acoustic transmitters have been used in the last 20 years to track fish movement for fish survival and migration behavior studies. However, the relatively large weights and sizes of commercial transmitters limit the populations of studied fish. The surgical implantation procedures may also affect fish adversely and incur a significant amount of labor. Therefore, a smaller, lighter, and injectable transmitter was needed, and similar or better acoustic performance and service life over those provided by existing commercial transmitters was desired. To develop such a small transmitter, a number of technical challenges, including design optimization of the piezoelectric transducer, needed to be overcome. Our efforts to optimize the transducer focused on improving the average source level in the 180° range in which the signal was not blocked by the transmitter body. We found that a novel off-center tube transducer improved the average source level by 1.5 dB. An acoustic reflector attached to the back of the transducer also improved the source level by 1.3 dB. We found that too small a gap between the transducer and the component placed behind it resulted in distortion of the beam pattern. Lastly, a tuning inductor in series with the transducer was used to help optimize the source level. The findings and techniques developed in this work contributed to the successful development and implementation of a new injectable transmitter.

  14. Piezoelectric transducer design for a miniaturized injectable acoustic transmitter

    SciTech Connect

    Li, Huidong; Jung, Ki Won; Deng, Zhiqun D.

    2015-10-07

    Acoustic telemetry has been an important tool in the last 20 years for studying fish survival and migration behaviors during and after dam passage. This technology uses implantable acoustic transmitters as tags to three-dimensionally track the movement of fish. However, the relatively large weights and sizes of commercially available transmitters limit the populations of fish that could be studied. The surgical implantation procedures required may also injure fish and also incur a significant amount of labor. Therefore, a smaller, lighter, and injectable tag was needed, and similar or better acoustic performance and service life over that provided by existing commercial tags was desired. To develop such a small transmitter, a number of technical challenges, including design optimization of the piezoelectric transducer, needed to be overcome. The goal of our efforts to optimize the transducer focused on improving the average source level in the 180° range in which the transmitter was facing the receiving hydrophone, so as to increase the transmitter’s detection probability. This paper reports the techniques that were explored and developed to achieve this goal. We found that a novel off-center tube transducer improved the average source level of the front half of the transducer by 1.5 dB. An acoustic reflector attached to the back of the transducer also improved the source level by 3 dB when the transducer was pointed toward the receiving hydrophone, although the source level on the sides of the transducer was reduced. We found that too small a gap between the transducer and the component placed behind it resulted in distortion of the beam pattern. To overcome that issue, we connected a tuning inductor in series with the transducer to help optimize the source level. Furthermore, the findings and techniques developed in this work contributed to the successful development and implementation of a new injectable transmitter.

  15. Piezoelectric transducer design for a miniaturized injectable acoustic transmitter

    DOE PAGES

    Li, Huidong; Jung, Ki Won; Deng, Zhiqun D.

    2015-10-07

    Acoustic telemetry has been an important tool in the last 20 years for studying fish survival and migration behaviors during and after dam passage. This technology uses implantable acoustic transmitters as tags to three-dimensionally track the movement of fish. However, the relatively large weights and sizes of commercially available transmitters limit the populations of fish that could be studied. The surgical implantation procedures required may also injure fish and also incur a significant amount of labor. Therefore, a smaller, lighter, and injectable tag was needed, and similar or better acoustic performance and service life over that provided by existing commercialmore » tags was desired. To develop such a small transmitter, a number of technical challenges, including design optimization of the piezoelectric transducer, needed to be overcome. The goal of our efforts to optimize the transducer focused on improving the average source level in the 180° range in which the transmitter was facing the receiving hydrophone, so as to increase the transmitter’s detection probability. This paper reports the techniques that were explored and developed to achieve this goal. We found that a novel off-center tube transducer improved the average source level of the front half of the transducer by 1.5 dB. An acoustic reflector attached to the back of the transducer also improved the source level by 3 dB when the transducer was pointed toward the receiving hydrophone, although the source level on the sides of the transducer was reduced. We found that too small a gap between the transducer and the component placed behind it resulted in distortion of the beam pattern. To overcome that issue, we connected a tuning inductor in series with the transducer to help optimize the source level. Furthermore, the findings and techniques developed in this work contributed to the successful development and implementation of a new injectable transmitter.« less

  16. Design of Fresnel Lens-Type Multi-Trapping Acoustic Tweezers

    PubMed Central

    Tu, You-Lin; Chen, Shih-Jui; Hwang, Yean-Ren

    2016-01-01

    In this paper, acoustic tweezers which use beam forming performed by a Fresnel zone plate are proposed. The performance has been demonstrated by finite element analysis, including the acoustic intensity, acoustic pressure, acoustic potential energy, gradient force, and particle distribution. The acoustic tweezers use an ultrasound beam produced by a lead zirconate titanate (PZT) transducer operating at 2.4 MHz and 100 Vpeak-to-peak in a water medium. The design of the Fresnel lens (zone plate) is based on air reflection, acoustic impedance matching, and the Fresnel half-wave band (FHWB) theory. This acoustic Fresnel lens can produce gradient force and acoustic potential wells that allow the capture and manipulation of single particles or clusters of particles. Simulation results strongly indicate a good trapping ability, for particles under 150 µm in diameter, in the minimum energy location. This can be useful for cell or microorganism manipulation. PMID:27886050

  17. Design of Fresnel Lens-Type Multi-Trapping Acoustic Tweezers.

    PubMed

    Tu, You-Lin; Chen, Shih-Jui; Hwang, Yean-Ren

    2016-11-23

    In this paper, acoustic tweezers which use beam forming performed by a Fresnel zone plate are proposed. The performance has been demonstrated by finite element analysis, including the acoustic intensity, acoustic pressure, acoustic potential energy, gradient force, and particle distribution. The acoustic tweezers use an ultrasound beam produced by a lead zirconate titanate (PZT) transducer operating at 2.4 MHz and 100 Vpeak-to-peak in a water medium. The design of the Fresnel lens (zone plate) is based on air reflection, acoustic impedance matching, and the Fresnel half-wave band (FHWB) theory. This acoustic Fresnel lens can produce gradient force and acoustic potential wells that allow the capture and manipulation of single particles or clusters of particles. Simulation results strongly indicate a good trapping ability, for particles under 150 µm in diameter, in the minimum energy location. This can be useful for cell or microorganism manipulation.

  18. Facilities for music education and their acoustical design.

    PubMed

    Koskinen, Heli; Toppila, Esko; Olkinuora, Pekka

    2010-01-01

    Good rehearsal facilities for musicians are essential. Directive 2003/10/EC necessitates that musicians are protected from noise exposure. A code of conduct gives the guidelines how this should be done. This study examines room acoustics recommendations provided by the Finnish code of conduct, and discusses whether they are adequate. Small teaching facilities were measured after renovation and compared to earlier measurements. Teachers' opinions were inquired about the facilities before and after. The renovation did not decrease the noise exposure of the teachers. However, the majority preferred the facilities after the renovation. The Finnish code of conduct is not sufficient for facilities where loud instruments are played, or band practise. Good facilities can be designed but they must be specified at the designing stage for their intended use.

  19. Changing space and sound: Parametric design and variable acoustics

    NASA Astrophysics Data System (ADS)

    Norton, Christopher William

    This thesis examines the potential for parametric design software to create performance based design using acoustic metrics as the design criteria. A former soundstage at the University of Southern California used by the Thornton School of Music is used as a case study for a multiuse space for orchestral, percussion, master class and recital use. The criteria used for each programmatic use include reverberation time, bass ratio, and the early energy ratios of the clarity index and objective support. Using a panelized ceiling as a design element to vary the parameters of volume, panel orientation and type of absorptive material, the relationships between these parameters and the design criteria are explored. These relationships and subsequently derived equations are applied to Grasshopper parametric modeling software for Rhino 3D (a NURBS modeling software). Using the target reverberation time and bass ratio for each programmatic use as input for the parametric model, the genomic optimization function of Grasshopper - Galapagos - is run to identify the optimum ceiling geometry and material distribution.

  20. Design of fluid-loaded piezoelectric transducers for acoustic power considerations

    NASA Astrophysics Data System (ADS)

    Grosh, Karl; Lin, Yuan; Nelli Silva, Emilio C.; Kikuchi, Noboru

    1998-07-01

    In this paper, a design methodology for enhancing the acoustic power radiated from fluid-loaded piezoelectric transducers at a particular operating frequency is developed. For many applications the operating frequency is fixed by the absorption of the material and the desired depth of penetration (e.g., therapeutic ultrasound). For therapeutic ultrasound and other industrial applications, the acoustic power is the critical figure of merit. The acoustic power radiated from the transducer system is computed from a finite element formulation of the coupled acoustic, elastic, piezoelectric equations of motion. The sensitivities of the acoustic power to two design variables: the length of the piezoelectric element and the thickness of the matching layer, are derived. Using these sensitivities, a novel design methodology in which remeshing is avoided is developed and the effectiveness of the method is studied. Results from the application of this framework for transducer design demonstrate the dramatic increase in radiated power possible from this two member design space.

  1. Design of acoustic metamaterials using the covariance matrix adaptation evolutionary strategy

    NASA Astrophysics Data System (ADS)

    Huang, Bei; Cheng, Qiang; Song, Gang Yong; Cui, Tie Jun

    2017-03-01

    Acoustic metamaterials can manipulate sound waves in surprising ways, including the focusing, cloaking, and extraordinary transmitting of sound waves. With the increasing requirements for acoustic metamaterials with extreme parameters, we propose the design of acoustic meta-atoms with a large refraction index using the covariance matrix adaptation evolutionary optimization strategy. To validate the procedure, we propose an optimized metamaterial to construct an acoustic deflection lens. The full-wave simulation results are consistent with the theoretical predictions, showing the efficacy and accuracy of the proposed method, and indicating that the optimization algorithm is a powerful tool for designing meta-atoms with excellent applications.

  2. Fluids and Combustion Facility Acoustic Emissions Controlled by Aggressive Low-Noise Design Process

    NASA Technical Reports Server (NTRS)

    Cooper, Beth A.; Young, Judith A.

    2004-01-01

    The Fluids and Combustion Facility (FCF) is a dual-rack microgravity research facility that is being developed by Northrop Grumman Information Technology (NGIT) for the International Space Station (ISS) at the NASA Glenn Research Center. As an on-orbit test bed, FCF will host a succession of experiments in fluid and combustion physics. The Fluids Integrated Rack (FIR) and the Combustion Integrated Rack (CIR) must meet ISS acoustic emission requirements (ref. 1), which support speech communication and hearing-loss-prevention goals for ISS crew. To meet these requirements, the NGIT acoustics team implemented an aggressive low-noise design effort that incorporated frequent acoustic emission testing for all internal noise sources, larger-scale systems, and fully integrated racks (ref. 2). Glenn's Acoustical Testing Laboratory (ref. 3) provided acoustical testing services (see the following photograph) as well as specialized acoustical engineering support as part of the low-noise design process (ref. 4).

  3. Design, fabrication and acoustic tests of a 36 inch (0.914 meter) statorless turbotip fan

    NASA Technical Reports Server (NTRS)

    Smith, E. G.; Stempert, D. L.; Uhl, W. R.

    1975-01-01

    The LF336/E is a 36 inch (0.914 meter) diameter fan designed to operate in a rotor-alone configuration. Design features required for modification of the existing LF336/A rotor-stator fan into the LF336/E statorless fan configuration are discussed. Tests of the statorless fan identified an aerodynamic performance deficiency due to inaccurate accounting of the fan exit swirl during the aerodynamic design. This performance deficiency, related to fan exit static pressure levels, produced about a 20 percent thrust loss. A study was then conducted for further evaluation of the fan exit flow fields typical of statorless fan systems. This study showed that through proper selection of fan design variables such as pressure ratio, radius ratio, and swirl distributions, performance of a statorless fan configuration could be improved with levels of thrust approaching the conventional rotor-stator fan system. Acoustic measurements were taken for the statorless fan system at both GE and NASA, and when compared to other lift fan systems, showed noise levels comparable to the quietest lift fan configuration which included rotor-stator spacing and acoustic treatment. The statorless fan system was also used to determine effects of rotor leading edge serrations on noise generations. A cascade test program identified the serration geometry based on minimum pressure losses, wake turbulence levels and noise generations.

  4. Perceptual and acoustic evaluation of individuals with laryngopharyngeal reflux pre- and post-treatment.

    PubMed

    Selby, Julia C; Gilbert, Harvey R; Lerman, J W

    2003-12-01

    Thirteen individuals with laryngopharyngeal reflux (LPR) were studied pre- and post-treatment. The effect of treatment on perceptual ratings of voice quality and frequency and intensity measures was examined. Relationships between perceptual and acoustic parameters were assessed descriptively. Results showed a small, but significant improvement in the perception of voice quality post-treatment. No significant differences were found between pre- and post-treatment means for any of the acoustic measures except harmonics-to-noise ratio (HNR). Descriptive analyses showed some association between perceptual ratings and acoustic measures. Discussion of results focuses on severity of LPR.

  5. Acoustically accessible window determination for ultrasound mediated treatment of glycogen storage disease type Ia patients

    NASA Astrophysics Data System (ADS)

    Wang, Shutao; Raju, Balasundar I.; Leyvi, Evgeniy; Weinstein, David A.; Seip, Ralf

    2012-10-01

    Glycogen storage disease type Ia (GSDIa) is caused by an inherited single-gene defect resulting in an impaired glycogen to glucose conversion pathway. Targeted ultrasound mediated delivery (USMD) of plasmid DNA (pDNA) to liver in conjunction with microbubbles may provide a potential treatment for GSDIa patients. As the success of USMD treatments is largely dependent on the accessibility of the targeted tissue by the focused ultrasound beam, this study presents a quantitative approach to determine the acoustically accessible liver volume in GSDIa patients. Models of focused ultrasound beam profiles for transducers of varying aperture and focal lengths were applied to abdomen models reconstructed from suitable CT and MRI images. Transducer manipulations (simulating USMD treatment procedures) were implemented via transducer translations and rotations with the intent of targeting and exposing the entire liver to ultrasound. Results indicate that acoustically accessible liver volumes can be as large as 50% of the entire liver volume for GSDIa patients and on average 3 times larger compared to a healthy adult group due to GSDIa patients' increased liver size. Detailed descriptions of the evaluation algorithm, transducer-and abdomen models are presented, together with implications for USMD treatments of GSDIa patients and transducer designs for USMD applications.

  6. On the acoustic wedge design and simulation of anechoic chamber

    NASA Astrophysics Data System (ADS)

    Jiang, Changyong; Zhang, Shangyu; Huang, Lixi

    2016-10-01

    This study proposes an alternative to the classic wedge design for anechoic chambers, which is the uniform-then-gradient, flat-wall (UGFW) structure. The working mechanisms of the proposed structure and the traditional wedge are analyzed. It is found that their absorption patterns are different. The parameters of both structures are optimized for achieving minimum absorber depth, under the condition of absorbing 99% of normal incident sound energy. It is found that, the UGFW structure achieves a smaller total depth for the cut-off frequencies ranging from 100 Hz to 250 Hz. This paper also proposes a modification for the complex source image (CSI) model for the empirical simulation of anechoic chambers, originally proposed by Bonfiglio et al. [J. Acoust. Soc. Am. 134 (1), 285-291 (2013)]. The modified CSI model considers the non-locally reactive effect of absorbers at oblique incidence, and the improvement is verified by a full, finite-element simulation of a small chamber. With the modified CSI model, the performance of both decorations with the optimized parameters in a large chamber is simulated. The simulation results are analyzed and checked against the tolerance of 1.5 dB deviation from the inverse square law, stipulated in the ISO standard 3745(2003). In terms of the total decoration depth and anechoic chamber performance, the UGFW structure is better than the classic wedge design.

  7. Design and fabrication of an augmentor wing model for acoustic tests

    NASA Technical Reports Server (NTRS)

    Jackson, J.; Schedin, R. W.; Campbell, J. M.

    1973-01-01

    The design and fabrication of a full-scale section of an augmentor wing to be used for acoustic testing at the Lewis Research Center are discussed. This hardware will be used primarily to investigate scaling effects of acoustic data obtained during the Boeing-run model tests. Typical model test data is shown in the report, together with predictions on both performance and acoustics that can be expected from the full-scale section to be built. Areas covered include: the aerodynamic and acoustic criteria of the flap system and nozzles, detailed discussion of the hardware, test system operation procedure, and stress analysis of the entire test system.

  8. Enhancement of Focused Ultrasound Treatment by Acoustically Generated Microbubbles

    NASA Astrophysics Data System (ADS)

    Umemura, Shin-ichiro; Yoshizawa, Shin; Takagi, Ryo; Inaba, Yuta; Yasuda, Jun

    2013-07-01

    Microbubbles, whether introduced from outside the body or ultrasonically generated in situ, are known to significantly enhance the biological effects of ultrasound, including the mechanical, thermal, and sonochemical effects. Phase-change nanodroplets, which selectively accumulate in tumor tissue and whose phase changes to microbubbles can be induced by ultrasonic stimulation, have been proposed for high-intensity focused ultrasound (HIFU) tumor treatment with enhanced selectivity and efficiency. In this paper, a purely acoustic approach to generate microbubble clouds in the tissue to be treated is proposed. Short pulses of focused ultrasound with extremely high intensity, named trigger pulses, are used for exposure. They are immediately followed by focused ultrasound for heating with an intensity similar to or less than that of normal HIFU treatment. The localized generation of microbubble clouds by the trigger pulses is observed in a polyarylamide gel by a high-speed camera, and the effectiveness of the generated clouds in accelerating ultrasonically induced thermal coagulation is confirmed in excised chicken breast tissue. The use of second-harmonic superimposed waves as the trigger pulses is also proposed. The highly reproducible initiation of cavitation by waves with the negative peak pressure emphasized and the efficient expansion of the generated microbubble clouds by waves with the positive peak pressure emphasized are also observed by a high-speed camera in partially degassed water.

  9. Design of acoustic beam aperture modifier using gradient-index phononic crystals

    NASA Astrophysics Data System (ADS)

    Lin, Sz-Chin Steven; Tittmann, Bernhard R.; Huang, Tony Jun

    2012-06-01

    This article reports the design concept of a novel acoustic beam aperture modifier using butt-jointed gradient-index phononic crystals (GRIN PCs) consisting of steel cylinders embedded in a homogeneous epoxy background. By gradually tuning the period of a GRIN PC, the propagating direction of acoustic waves can be continuously bent to follow a sinusoidal trajectory in the structure. The aperture of an acoustic beam can therefore be shrunk or expanded through change of the gradient refractive index profiles of the butt-jointed GRIN PCs. Our computational results elucidate the effectiveness of the proposed acoustic beam aperture modifier. Such an acoustic device can be fabricated through a simple process and will be valuable in applications, such as biomedical imaging and surgery, nondestructive evaluation, communication, and acoustic absorbers.

  10. The Acoustic Voice Quality Index: Toward Improved Treatment Outcomes Assessment in Voice Disorders

    ERIC Educational Resources Information Center

    Maryn, Youri; De Bodt, Marc; Roy, Nelson

    2010-01-01

    Voice practitioners require an objective index of dysphonia severity as a means to reliably track treatment outcomes. To ensure ecological validity however, such a measure should survey both sustained vowels and continuous speech. In an earlier study, a multivariate acoustic model referred to as the Acoustic Voice Quality Index (AVQI), consisting…

  11. Towards optimal design of locally resonant acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Krushynska, A. O.; Kouznetsova, V. G.; Geers, M. G. D.

    2014-11-01

    The paper presents an in-depth analysis of solid locally resonant acoustic metamaterials (LRAMs) consisting of rubber-coated inclusions. Dispersion properties of two-dimensional LRAMs are studied by means of finite-element modal analysis. For an incompressible rubber, only one practically important spectral band gap is found for in-plane modes in a low-frequency range. This result is in striking contrast with the compressible coating case, previously studied in the literature. For inclusions with a circular cross-section, the lower bound of the band gap can be evaluated exactly by means of the derived analytical solution, which is also valid for compressible coatings and can therefore be used to determine lower bounds of higher band gaps as well. The influence of geometric and material parameters, filling fraction and inclusion shape on the width of the lowest band gap is investigated in detail. Based on the results of this analysis, an optimal microstructure of LRAMs yielding the widest low-frequency band gap is proposed. To achieve the band gap at the lowest possible frequencies in LRAMs suitable for practical applications, the use of the tungsten core material is advised, as a safe and economically viable alternative to commonly considered lead and gold. Two configurations of LRAM with various sizes of coated tungsten cylindrical inclusions with circular cross-section are considered. The evolution of dispersion spectra due to the presence of different inclusions is investigated, and the parameters for optimal design of LRAMs are determined.

  12. LINAC radiosurgery and radiotherapy treatment of acoustic neuromas. 2007.

    PubMed

    Likhterov, Ilya; Allbright, Robert M; Selesnick, Samuel H

    2008-04-01

    This article provides an introduction to radiation therapy as it applies to intracranial tumors. It also provides a review of the natural growth progression of acoustic neuromas and accuracy of tumor size determination. Literature on the use of linear accelerator stereotactic radiosurgery and fractionated radiotherapy in acoustic neuroma management is reviewed and summarized. Specifically, the rates of reported tumor control, hearing preservation, facial and trigeminal nerve complications, and hydrocephalus are analyzed. Although the complication rates associated with linear accelerator therapy are relatively low, hearing preservation is poor and acoustic neuroma control is variable.

  13. LINAC radiosurgery and radiotherapy treatment of acoustic neuromas.

    PubMed

    Likhterov, Ilya; Allbright, Robert M; Selesnick, Samuel H

    2007-06-01

    This article provides an introduction to radiation therapy as it applies to intracranial tumors. It also provides a review of the natural growth progression of acoustic neuromas and accuracy of tumor size determination. Literature on the use of linear accelerator stereotactic radiosurgery and fractionated radiotherapy in acoustic neuroma management is reviewed and summarized. Specifically, the rates of reported tumor control, hearing preservation, facial and trigeminal nerve complications, and hydrocephalus are analyzed. Although the complication rates associated with linear accelerator therapy are relatively low, hearing preservation is poor and acoustic neuroma control is variable.

  14. A research program to reduce interior noise in general aviation airplanes. Design of an acoustic panel test facility

    NASA Technical Reports Server (NTRS)

    Roskam, J.; Muirhead, V. U.; Smith, H. W.; Henderson, T. D.

    1977-01-01

    The design, construction, and costs of a test facility for determining the sound transmission loss characteristics of various panels and panel treatments are described. The pressurization system and electronic equipment used in experimental testing are discussed as well as the reliability of the facility and the data gathered. Tests results are compared to pertinent acoustical theories for panel behavior and minor anomalies in the data are examined. A method for predicting panel behavior in the stiffness region is also presented.

  15. A preliminary design study on an acoustic muffler for the laminar flow transition research apparatus

    NASA Technical Reports Server (NTRS)

    Abrahamson, A. L.

    1984-01-01

    An acoustic muffler design of a research tool for studying laminar flow and the mechanisms of transition, the Laminar Flow and Transition Research Apparatus (LFTRA) is investigated. Since the presence of acoustic pressure fluctuations is known to affect transition, low background noise levels in the test section of the LFTRA are mandatory. The difficulties and tradeoffs of various muffler design concepts are discussed and the most promising candidates are emphasized.

  16. Design of acoustic logging signal source of imitation based on field programmable gate array

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Ju, X. D.; Lu, J. Q.; Men, B. Y.

    2014-08-01

    An acoustic logging signal source of imitation is designed and realized, based on the Field Programmable Gate Array (FPGA), to improve the efficiency of examining and repairing acoustic logging tools during research and field application, and to inspect and verify acoustic receiving circuits and corresponding algorithms. The design of this signal source contains hardware design and software design,and the hardware design uses an FPGA as the control core. Four signals are made first by reading the Random Access Memory (RAM) data which are inside the FPGA, then dealing with the data by digital to analog conversion, amplification, smoothing and so on. Software design uses VHDL, a kind of hardware description language, to program the FPGA. Experiments illustrate that the ratio of signal to noise for the signal source is high, the waveforms are stable, and also its functions of amplitude adjustment, frequency adjustment and delay adjustment are in accord with the characteristics of real acoustic logging waveforms. These adjustments can be used to imitate influences on sonic logging received waveforms caused by many kinds of factors such as spacing and span of acoustic tools, sonic speeds of different layers and fluids, and acoustic attenuations of different cementation planes.

  17. Design optimization of composite structures operating in acoustic environments

    NASA Astrophysics Data System (ADS)

    Chronopoulos, D.

    2015-10-01

    The optimal mechanical and geometric characteristics for layered composite structures subject to vibroacoustic excitations are derived. A Finite Element description coupled to Periodic Structure Theory is employed for the considered layered panel. Structures of arbitrary anisotropy as well as geometric complexity can thus be modelled by the presented approach. Damping can also be incorporated in the calculations. Initially, a numerical continuum-discrete approach for computing the sensitivity of the acoustic wave characteristics propagating within the modelled periodic composite structure is exhibited. The first- and second-order sensitivities of the acoustic transmission coefficient expressed within a Statistical Energy Analysis context are subsequently derived as a function of the computed acoustic wave characteristics. Having formulated the gradient vector as well as the Hessian matrix, the optimal mechanical and geometric characteristics satisfying the considered mass, stiffness and vibroacoustic performance criteria are sought by employing Newton's optimization method.

  18. Attenuation of sound in ducts with acoustic treatment: A generalized approximate equation

    NASA Technical Reports Server (NTRS)

    Rice, E. J.

    1975-01-01

    A generalized approximate equation for duct lining sound attenuation is presented. The specification of two parameters, the maximum possible attenuation and the optimum wall acoustic impedance is shown to completely determine the sound attenuation for any acoustic mode at any selected wall impedance. The equation is based on the nearly circular shape of the constant attenuation contours in the wall acoustic impedance plane. For impedances far from the optimum, the equation reduces to Morse's approximate expression. The equation can be used for initial acoustic liner design. Not least important is the illustrative nature of the solutions which provide an understanding of the duct propagation problem usually obscured in the exact calculations. Sample calculations using the approximate attenuation equation show that the peak and the bandwidth of the sound attenuation spectrum can be represented by quite simple functions of the ratio of actual wall acoustic resistance to optimum resistance.

  19. Acoustics in Research Facilities--Control of Wanted and Unwanted Sound. Laboratory Design Notes.

    ERIC Educational Resources Information Center

    Newman, Robert B.

    Common and special acoustics problems are discussed in relation to the design and construction of research facilities. Following a brief examination of design criteria for the control of wanted and unwanted sound, the technology for achieving desired results is discussed. Emphasis is given to various design procedures and materials for the control…

  20. Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

    PubMed

    Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

    2016-03-01

    Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect.

  1. The Testing Behind The Test Facility: The Acoustic Design of the NASA Glenn Research Center's World-Class Reverberant Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Mark E.; McNelis, Anne M.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC?s Plum Brook Station in Sandusky, Ohio, USA. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA?s space exploration program. T he large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 ft3 in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world?s known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada?s acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama, USA. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic de-sign and subsequent on-going construction.

  2. The Testing Behind the Test Facility: the Acoustic Design of the NASA Glenn Research Center's World-Class Reverberant Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Mark E.; Hozman, Aron D.; McNelis, Anne M.

    2010-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC s Plum Brook Station in Sandusky, Ohio, U.S.A. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA s space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 ft3 in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world s known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada s acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama, U.S.A. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent ongoing construction.

  3. The Testing Behind The Test Facility: The Acoustic Design of the NASA Glenn Research Center's World-Class Reverberant Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Hozman, Aron D.; Hughes, William O.; McNelis, Mark E.; McNelis, Anne M.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC's Plum Brook Station in Sandusky, Ohio, USA. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA's space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 cu ft in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world's known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada's acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama, USA. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent on-going construction.

  4. Counterpoint: the treatment decision design.

    PubMed

    Brookhart, M Alan

    2015-11-15

    The comparative new-user design is a principled approach to learning about the relative risks and benefits of starting different treatments in patients who have no history of use of the treatments being studied. Vandenbroucke and Pearce (Am J Epidemiol. 2015;182(10):826-833) discuss some problems inherent in incident exposure designs and argue that epidemiology may be harmed by a rigid requirement that follow-up can only begin at first exposure. In the present counterpoint article, a range of problems in pharmacoepidemiology that do not necessarily require that observation begin at first exposure are discussed. For example, among patients who are past or current users of a medication, we might want to know whether treatment should be augmented, switched, restarted, or discontinued. To answer these questions, a generalization of the new-user design, the treatment decision design, which identifies cohorts anchored at times when treatment decisions are being made, such as the evaluation of laboratory parameters, is discussed. The design aims to provide estimates that are directly relevant to physicians and patients, helping them to better understand the risks and benefits of the different treatment choices that they are considering.

  5. Design and Analysis of Underwater Acoustic Networks with Reflected Links

    NASA Astrophysics Data System (ADS)

    Emokpae, Lloyd

    Underwater acoustic networks (UWANs) have applications in environmental state monitoring, oceanic profile measurements, leak detection in oil fields, distributed surveillance, and navigation. For these applications, sets of nodes are employed to collaboratively monitor an area of interest and track certain events or phenomena. In addition, it is common to find autonomous underwater vehicles (AUVs) acting as mobile sensor nodes that perform search-and-rescue missions, reconnaissance in combat zones, and coastal patrol. These AUVs are to work cooperatively to achieve a desired goal and thus need to be able to, in an ad-hoc manner, establish and sustain communication links in order to ensure some desired level of quality of service. Therefore, each node is required to adapt to environmental changes and be able to overcome broken communication links caused by external noise affecting the communication channel due to node mobility. In addition, since radio waves are quickly absorbed in the water medium, it is common for most underwater applications to rely on acoustic (or sound) rather than radio channels for mid-to-long range communications. However, acoustic channels pose multiple challenging issues, most notably the high transmission delay due to slow signal propagation and the limited channel bandwidth due to high frequency attenuation. Moreover, the inhomogeneous property of the water medium affects the sound speed profile while the signal surface and bottom reflections leads to multipath effects. In this dissertation, we address these networking challenges by developing protocols that take into consideration the underwater physical layer dynamics. We begin by introducing a novel surface-based reflection scheme (SBR), which takes advantage of the multipath effects of the acoustic channel. SBR works by using reflections from the water surface, and bottom, to establish non-line-of-sight (NLOS) communication links. SBR makes it possible to incorporate both line

  6. Acoustical design economic trade off for transport aircraft

    NASA Astrophysics Data System (ADS)

    Benito, A.

    The effects of ICAO fixed certification limits and local ordinances on acoustic emissions from jets on commercial transport aircraft and costs of operations are explored. The regulations effectively ban some aircraft from operation over populated areas, impose curfews on airports and, in conjunction with local civil aviation rules, levy extra taxes and quotas on noisier equipment. Jet engine manufacturers have attempted to increase the flow laminarity, decrease the exhaust speed and develop acoustic liners for selected duct areas. Retrofits are, however, not usually cost effective due to increased operational costs, e.g., fuel consumption can increase after engine modification because of increased weight. Finally, an attempt is made to assess, monetarily, the costs of noise pollution, wherein fines are levied for noisy aircraft and the money is spent insulating homes from noise.

  7. Optimum acoustic design of free-running low speed propellers

    NASA Technical Reports Server (NTRS)

    Ormsbee, A. I.; Woan, C. J.

    1977-01-01

    A theoretical analysis is conducted concerning the effect of blade loading on the noise output of a free-running propeller in axial motion. The minimization of the mean square sound pressure at a point in space is considered, taking into account constraints on propeller thrust and torque. Attention is given to aerodynamic equations, acoustic equations, the expansion of the aerodynamic variables, and the nonlinear programming formulation.

  8. Design and performance of the South Pole Acoustic Test Setup

    NASA Astrophysics Data System (ADS)

    Abdou, Y.; Becker, K.-H.; Berdermann, J.; Bissok, M.; Bohm, C.; Böser, S.; Bothe, M.; Carson, M.; Descamps, F.; Fischer-Wolfarth, J.-H.; Gustafsson, L.; Hallgren, A.; Heinen, D.; Helbing, K.; Heller, R.; Hundertmark, S.; Karg, T.; Krieger, K.; Laihem, K.; Meures, T.; Nahnhauer, R.; Naumann, U.; Oberson, F.; Paul, L.; Pohl, M.; Price, B.; Ribordy, M.; Ryckbosch, D.; Schunck, M.; Semburg, B.; Stegmaier, J.; Sulanke, K.-H.; Tosi, D.; Vandenbroucke, J.; Wiebusch, C.

    2012-08-01

    The South Pole Acoustic Test Setup (SPATS) was built to evaluate the acoustic characteristics of the South Pole ice in the 10-100 kHz frequency range, for the purpose of assessing the feasibility of an acoustic neutrino detection array at the South Pole. The SPATS hardware consists of four vertical strings deployed in the upper 500 m of the South Pole ice cap. The strings form a trapezoidal array with a maximum baseline of 543 m. Each string has seven stages equipped with one transmitter and one sensor module (glaciophone). Sound is detected or generated by piezoelectric ceramic elements inside the modules. Analogue signals are sent to the surface on electric cables where they are digitized by a PC-based data acquisition system. The data from all strings are collected on a central computer in the IceCube Laboratory from where they are sent to a central data storage facility via a satellite link or stored locally on tape. A technical overview of SPATS and its performance is presented.

  9. Harnessing fluid-structure interactions to design self-regulating acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Casadei, Filippo; Bertoldi, Katia

    2014-01-01

    The design of phononic crystals and acoustic metamaterials with tunable and adaptive wave properties remains one of the outstanding challenges for the development of next generation acoustic devices. We report on the numerical and experimental demonstration of a locally resonant acoustic metamaterial with dispersion characteristics, which autonomously adapt in response to changes of an incident aerodynamic flow. The metamaterial consists of a slender beam featuring a periodic array or airfoil-shaped masses supported by a linear and torsional springs. The resonance characteristics of the airfoils lead to strong attenuation at frequencies defined by the properties of the airfoils and the speed on the incident fluid. The proposed concept expands the ability of existing acoustic bandgap materials to autonomously adapt their dispersion properties through fluid-structure interactions, and has the potential to dramatically impact a variety of applications, such as robotics, civil infrastructures, and defense systems.

  10. Harnessing fluid-structure interactions to design self-regulating acoustic metamaterials

    SciTech Connect

    Casadei, Filippo; Bertoldi, Katia

    2014-01-21

    The design of phononic crystals and acoustic metamaterials with tunable and adaptive wave properties remains one of the outstanding challenges for the development of next generation acoustic devices. We report on the numerical and experimental demonstration of a locally resonant acoustic metamaterial with dispersion characteristics, which autonomously adapt in response to changes of an incident aerodynamic flow. The metamaterial consists of a slender beam featuring a periodic array or airfoil-shaped masses supported by a linear and torsional springs. The resonance characteristics of the airfoils lead to strong attenuation at frequencies defined by the properties of the airfoils and the speed on the incident fluid. The proposed concept expands the ability of existing acoustic bandgap materials to autonomously adapt their dispersion properties through fluid-structure interactions, and has the potential to dramatically impact a variety of applications, such as robotics, civil infrastructures, and defense systems.

  11. A procedure for combining acoustically induced and mechanically induced loads (first passage failure design criterion)

    NASA Technical Reports Server (NTRS)

    Crowe, D. R.; Henricks, W.

    1983-01-01

    The combined load statistics are developed by taking the acoustically induced load to be a random population, assumed to be stationary. Each element of this ensemble of acoustically induced loads is assumed to have the same power spectral density (PSD), obtained previously from a random response analysis employing the given acoustic field in the STS cargo bay as a stationary random excitation. The mechanically induced load is treated as either (1) a known deterministic transient, or (2) a nonstationary random variable of known first and second statistical moments which vary with time. A method is then shown for determining the probability that the combined load would, at any time, have a value equal to or less than a certain level. Having obtained a statistical representation of how the acoustic and mechanical loads are expected to combine, an analytical approximation for defining design levels for these loads is presented using the First Passage failure criterion.

  12. International Space Station USOS Crew Quarters Ventilation and Acoustic Design Implementation

    NASA Technical Reports Server (NTRS)

    Broyan, James Lee, Jr.

    2009-01-01

    The International Space Station (ISS) United States Operational Segment (USOS) has four permanent rack sized ISS Crew Quarters (CQ) providing a private crewmember space. The CQ uses Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air from the ISS Temperature Humidity Control System or the ISS fluid cooling loop connections. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crewmember s head position and reduce acoustic exposure. The CQ interior needs to be below Noise Curve 40 (NC-40). The CQ ventilation ducts are open to the significantly louder Node 2 cabin aisle way which required significantly acoustic mitigation controls. The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

  13. Acoustic Duration Changes Associated with Two Types of Treatment for Children Who Stutter.

    ERIC Educational Resources Information Center

    Riley, Glyndon D.; Ingham, Janis Costello

    2000-01-01

    This study examined acoustic durations in 12 children (ages 3 to 9) who stuttered and received treatment based either on speech motor training (SMT) or extended length of utterance (ELU). Although the ELU treatment reduced stuttering more than the SMT, the SMT was more effective in increasing vowel duration and decreasing stop gap duration.…

  14. Radiometric and photometric design for an Acoustic Containerless Experiment System. [for space processing

    NASA Technical Reports Server (NTRS)

    Glavich, T. A.

    1981-01-01

    The design of an optical system for a high temperature Acoustic Containerless Experiment System is examined. The optical system provides two-axis video, cine and infrared images of an acoustically positioned sample over a temperature range of 20 to 1200 C. Emphasis is placed on the radiometric and photometric characterization of the elements in the optical system and the oven to assist image data determination. Sample visibility due to wall radiance is investigated along with visibility due to strobe radiance. The optical system is designed for operation in Spacelab, and is used for a variety of materials processing experiments.

  15. A Design Process for the Acoustical System of an Enclosed Space Colony

    NASA Technical Reports Server (NTRS)

    Hawke, Joanne

    1981-01-01

    Sounds of Silence. Using a general systems approach, factors and components of the acoustical design process for an isolated, confined space community in a torus space enclosure are considered. These components include the following: organizational structure and its effect on alternatives; problem definition and limits; criteria and priorities; methods of data gathering; modelling and measurement of the whole system and its components; decision methods; and design scenario of the acoustics of the complex, socio-technical space community system with emphasis on the human factors.

  16. Optimal acoustical design of commercial meeting and teleconference rooms

    NASA Astrophysics Data System (ADS)

    Campanella, Angelo

    2002-05-01

    Along with a quiet NC-25 environment, speech communication among multiple individuals in a conference room, especially for teleconferencing, should be enhanced. Conferees are often located around a table and along the room perimeter. Speech propagation among all is enhanced by a flat ceiling reflector placed as low as practical over the table and the seated participants. This reinforces direct sound with a first-bounce reflection between all parties and microphones. Ceiling perimeter, 50%-75% of the ceiling area, is absorptive. This arrangement works for a speaker-phone and for microphones placed on the ceiling reflector avoiding paper shuffling noise. In the latter case, loudspeakers are placed on the absorbing perimeter acoustical tile. Absorption must be placed on the sidewalls to avoid flutter echoes. Uneven absorber distribution among surfaces is evaluated with the Fitzroy reverberation time [D. Fitzroy, J. Acoust. Soc. Am. 31, 893-897 (1959)]. It was found that this RT at 500 Hz should be [1+log(V)]/10 (about 1/2 s) to avoid a ``hollow'' timbre in purveyed speech. Examples of good and troublesome teleconference rooms are discussed.

  17. Acoustic testing of a supersonic tip speed fan with acoustic treatment and rotor casting slots. Quiet engine program scale model fan C

    NASA Technical Reports Server (NTRS)

    Kazin, S. B.

    1973-01-01

    Acoustic tests were conducted on a high tip speed (1550 ft/sec, 472.44 m/sec) single stage fan with varying amounts of wall acoustic treatment and with circumferential slots over the rotor blade tips. The slots were also tested with acoustic treatment placed behind the slots. The wall treatment results show that the inlet treatment is more effective at high fan speeds and aft duct treatment is more effective at low fan speeds. Maximum PNL's on a 200-foot (60.96 m) sideline show the untreated slots to have increased the rear radiated noise at approach. However, when the treatment was added to the slots inlet radiated noise was decreased, resulting in little change relative to the solid casing on an EPNL basis.

  18. Design, construction, activation, and operation of a high intensity acoustic test chamber

    NASA Technical Reports Server (NTRS)

    Kamel, L. T.

    1986-01-01

    The design philosophy, construction, integration, and activation of the high intensity acoustic test chamber for production acceptance testing of satellites are discussed. The 32,000 cubic-foot acoustic test cell consists of a steel reinforced concrete chamber with six electropneumatic noise generators. One of the innovative features of the chamber is a unique quarter horn assembly that acoustically couples the noise generators to the chamber. Design concepts, model testing, and evaluation results are presented. Considerations such as nitrogen versus compressed air source, digital closed loop spectrum control versus manual equalizers, and microprocessor based interlock systems are included. Construction difficulties, anomalies encountered, and their resolution are also discussed. Results of the readiness testing are highlighted.

  19. An acoustic head simulator for hearing protector evaluation. I: Design and construction.

    PubMed

    Kunov, H; Giguère, C

    1989-03-01

    As an alternative to subjective methods, an acoustic head simulator was constructed for hearing protector evaluation. The primary purpose of the device is for hearing protector testing and research under high-level steady-state and impulse noise environments. The design is based on the KEMAR manikin and therefore approximates the physical dimensions and the acoustical eardrum impedance of the median human adult. The head simulator includes a mechanical reproduction of the human circumaural and intraaural tissues with a silicone rubber material. A compliant head-neck system was constructed to approximate the vibrational characteristics of the human head in a sound field in order to simulate the inertia effect of earmuffs. The bone-conducted sounds are not mechanically reproduced in the design. Applications for the device are reported in a companion article [C. Giguère and H. Kunov, J. Acoust. Soc. Am. 85, 1197-1205 (1989)].

  20. The acoustical design of vehicles-a challenge for qualitative evaluation

    NASA Astrophysics Data System (ADS)

    Schulte-Fortkamp, Brigitte; Genuit, Klaus; Fiebig, Andre

    2005-09-01

    Whenever the acoustical design of vehicles is explored, the crucial question about the appropriate method of evaluation arises. Research shows that not only acoustic but also non-acoustic parameters have a major influence on the way sounds are evaluated. Therefore, new methods of evaluation have to be implemented. Methods are needed which give the opportunity to test the quality of the given ambience and to register the effects and evaluations in their functional interdependence as well as the influence of personal and contextual factors. Moreover, new methods have to give insight into processes of evaluation and their contextual parameters. In other words, the task of evaluating acoustical ambiences consists of designating a set of social, psychological, and cultural conditions which are important to determine particular individual and collective behavior, attitudes, and also emotions relative to the given ambience. However, no specific recommendations exist yet which comprise particular descriptions of how to assess those specific sound effects. That is why there is a need to develop alternative methods of evaluation with whose help effects of acoustical ambiences can be better predicted. A method of evaluation will be presented which incorporates a new sensitive approach for the evaluation of vehicle sounds.

  1. Designing an Acoustic Suspension Speaker System in the General Physics Laboratory: A Divergent experiment

    ERIC Educational Resources Information Center

    Horton, Philip B.

    1969-01-01

    Describes a student laboratory project involving the design of an "acoustic suspension speaker system. The characteristics of the loudspeaker used are measured as an extension of the inertia-balance experiment. The experiment may be extended to a study of Stelmholtz resonators, coupled oscillators, electromagnetic forces, thermodynamics and…

  2. Design of acoustic cell settler for filtering and recycling microbial cells.

    PubMed

    Hwang, Sung-Ho; Koo, Yoon-Mo

    2003-02-01

    An acoustic cell settler (ACS) using ultrasound at cells of 3 MHz was used to recycle Saccharomyces cerevisiae in a fermenter. The locations of both the inlet and outlet in the acoustic cell settler, which have a relatively long distance between the transducer and reflector, were optimized. A tilted settler was designed to make up for the defect in the horizontal ACS, which has a low recovery ratio. The tilted ACS gave a recovery ratio of yeast cells of about 5 during the most period of operation, which was twice that of the horizontal ACS.

  3. MEMS acoustic emission transducers designed with high aspect ratio geometry

    NASA Astrophysics Data System (ADS)

    Saboonchi, H.; Ozevin, D.

    2013-09-01

    In this paper, micro-electro-mechanic systems (MEMS) acoustic emission (AE) transducers are manufactured using an electroplating technique. The transducers use a capacitance change as their transduction principle, and are tuned to the range 50-200 kHz. Through the electroplating technique, a thick metal layer (20 μm nickel + 0.5 μm gold) is used to form a freely moving microstructure layer. The presence of the gold layer reduces the potential corrosion of the nickel layer. A dielectric layer is deposited between the two electrodes, thus preventing the stiction phenomenon. The transducers have a measured quality factor in the range 15-30 at atmospheric pressure and are functional without vacuum packaging. The transducers are characterized using electrical and mechanical tests to identify the capacitance, resonance frequency and damping. Ultrasonic wave generation using a Q-switched laser shows the directivity of the transducer sensitivity. The comparison of the MEMS transducers with similar frequency piezoelectric transducers shows that the MEMS AE transducers have better response characteristics and sensitivity at the resonance frequency and well-defined waveform signatures (rise time and decay time) due to pure resonance behavior in the out-of-plane direction. The transducers are sensitive to a unique wave direction, which can be utilized to increase the accuracy of source localization by selecting the correct wave velocity at the structures.

  4. Conceptual design study of advanced acoustic-composite nacelles

    NASA Technical Reports Server (NTRS)

    Nordstrom, K. E.; Marsh, A. H.; Sargisson, D. F.

    1975-01-01

    Conceptual studies were conducted to assess the impact of incorporating advanced technologies in the nacelles of a current wide-bodied transport and an advanced technology transport. The improvement possible in the areas of fuel consumption, flyover noise levels, airplane weight, manufacturing costs, and airplane operating cost were evaluated for short and long-duct nacelles. Use of composite structures for acoustic duct linings in the fan inlet and exhaust ducts was considered as well as for other nacelle components. For the wide-bodied transport, the use of a long-duct nacelle with an internal mixer nozzle in the primary exhaust showed significant improvement in installed specific fuel consumption and airplane direct operating costs compared to the current short-duct nacelle. The long-duct mixed-flow nacelle is expected to achieve significant reductions in jet noise during takeoff and in turbo-machinery noise during landing approach. Recommendations were made of the technology development needed to achieve the potential fuel conservation and noise reduction benefits.

  5. Analytical models for use in fan inflow control structure design. Inflow distortion and acoustic transmission models

    NASA Technical Reports Server (NTRS)

    Gedge, M. R.

    1979-01-01

    Analytical models were developed to study the effect of flow contraction and screening on inflow distortions to identify qualitative design criteria. Results of the study are that: (1) static testing distortions are due to atmospheric turbulence, nacelle boundary layer, exhaust flow reingestion, flow over stand, ground plane, and engine casing; (2) flow contraction suppresses, initially, turbulent axial velocity distortions and magnifies turbulent transverse velocity distortions; (3) perforated plate and gauze screens suppress axial components of velocity distortions to a degree determined by the screen pressure loss coefficient; (4) honeycomb screen suppress transverse components of velocity distortions to a degree determined by the length to diameter ratio of the honeycomb; (5) acoustic transmission loss of perforated plate is controlled by the reactance of its acoustic impedance; (6) acoustic transmission loss of honeycomb screens is negligible; and (7) a model for the direction change due to a corner between honeycomb panels compares favorably with measured data.

  6. SU-E-T-536: Inhomogeneity Correction in Planning of Gamma Knife Treatments for Acoustic Schwannoma

    SciTech Connect

    Lu, L; Gupta, N; Hessler, J; Liu, A; Weldon, M; McGregor, J; Ammirati, M; Guiou, M; Xia, F; Grecula, J

    2014-06-01

    Purpose: To find out the dose difference on targets and organs at risk for the treatment of acoustic schwannoma if the inhomogeneity correction (Convolution algorithm) is applied. Methods: Images of patients treated for acoustic schwannoma with Gamma Knife using TMR 10 algorithm were retrieved from database and replanned with Convolution and TMR 10 algorithm respectively. These patients were treated using a preplan scheme in following: (1) Before the actual treatment day, using the MRI image that was taken without a head frame on the patient's skull, a pre-treatment plan was made based on the default skull coordinates in the Gamma Knife treatment planning system (LGP); (2) then on treatment day, a head frame was placed on the patient's skull, and a CT image was taken. The CT image with head frame was registered and fused with the completed preplan; (3) the treatment plan was finalized and the treatment was delivered. To find out the dosimetry impact of inhomogeneity correction, we used the retrieved CT images to replan the treatment using Convolution algorithm in LGP software version 10.1.1. The dose distributions and the dose volume histograms for targets and OARs were compared for these two dose calculation algorithms. Results: The dose calculated with the Convolution algorithm in general is slightly lower than the one from TMR 10 around the boney area. The effect from the inhomogeneity correction is observable but not significant, and varies with the location of the tumor. Conclusion: Inhomogeneity correction slightly improve the dose accuracy for acoustic schwannoma Gamma Knife treatments although the correction may not be very significant. Our Result provides evidence for dose prescription adjustment to treat acoustic schwannoma. The actual clinical outcome of switching from using TMR10 to using Convolution needs to be further investigated.

  7. Acoustic sounder system design for measurement of optical turbulence and wind profiles

    NASA Astrophysics Data System (ADS)

    Miller, Judith E.; Eaton, Frank D.; Stokes, Sheldon S.

    2000-07-01

    An Acoustic Sounder System has been installed on the side of the cliff at North Oscura Peak, WSMR to provide important refractive index structure parameter, Cn2 data for laser propagation tests. The acoustic sounder system records echo information that is used to provide 3D wind and optical turbulence profiles. The received signal is the product of the interaction of the transmitted acoustic pulse with the small scale atmospheric temperature variations. This information is displayed as a time-height display of the signal intensity. The frequency of the received signals are processed and converted into time histories of the horizontal wind field. The data from the Acoustic Sounder is calibrated with the hot-wire anemometer temperature structure parameter (Ct2) data, and meteorological data measured locally to produce the Cn2 profile. The design and location of the Acoustic Sounder System will be discussed along with the methodology of extracting the turbulence. Many days of data have been collected and representative data will be shown.

  8. Acoustic fatigue and sound transmission characteristics of a ram composite panel design

    NASA Technical Reports Server (NTRS)

    Cockburn, J. A.; Chang, K. Y.; Kao, G. C.

    1972-01-01

    An experimental study to determine the acoustic fatigue characteristics of a flat multi-layered structural panel is described. The test panel represented a proposed design for the outer skin of a research application module to be housed within the space shuttle orbiter vehicle. The test specimen was mounted in one wall of the Wyle 100,000 cu ft reverberation room and exposed to a broadband acoustic environment having an overall level of 145 db. The test panel was exposed to nine separate applications of the acoustic environment, each application consisting of 250 seconds duration. Upon completion of the ninth test run, the specimen was exposed to a simulated micrometeoroid impact near the panel center. One additional test run of 250 seconds duration was then performed to complete the overall simulation of 50 flight missions. The experimental results show that no significant fatigue damage occurred until the test specimen was exposed to a simulated micrometeoroid impact. The intermediate foam layer forming the core of the test specimen suffered considerable damage due to this impact, causing a marked variation in the dynamic characteristics of the overall test panel. During the final application of the acoustic environment, the strain and acceleration response spectra showed considerable variation from those spectra obtained prior to impact of the panel. Fatigue damage from acoustic loading however, was limited to partial de-bonding around the edges of the composite panel.

  9. Acoustic Analysis and Design of the E-STA MSA Simulator

    NASA Technical Reports Server (NTRS)

    Bittinger, Samantha A.

    2016-01-01

    The Orion European Service Module Structural Test Article (E-STA) Acoustic Test was completed in May 2016 to verify that the European Service Module (ESM) can withstand qualification acoustic environments. The test article required an aft closeout to simulate the Multi-Purpose Crew Vehicle (MPCV) Stage Adapter (MSA) cavity, however, the flight MSA design was too cost-prohibitive to build. NASA Glenn Research Center (GRC) had 6 months to design an MSA Simulator that could recreate the qualification prediction MSA cavity sound pressure level to within a reasonable tolerance. This paper summarizes the design and analysis process to arrive at a design for the MSA Simulator, and then compares its performance to the final prediction models created prior to test.

  10. Design and Integration of a Rotor Alone Nacelle for Acoustic Fan Testing

    NASA Technical Reports Server (NTRS)

    Shook, Tony D.; Hughes, Christoper E.; Thompson, William K.; Tavernelli, Paul F.; Cunningham, Cameron C.; Shah, Ashwin

    2001-01-01

    A brief summary of the design, integration and testing of a rotor alone nacelle (RAN) in NASA Glenn's 9'x 15' Low Speed Wind Tunnel (LSWT) is presented. The purpose of the RAN system was to provide an "acoustically clean" flow path within the nacelle to isolate that portion of the total engine system acoustic signature attributed to fan noise. The RAN design accomplished this by removing the stators that provided internal support to the nacelle. In its place, two external struts mounted to a two-axis positioning table located behind the tunnel wall provided the support. Nacelle-mounted lasers and a closed-loop control system provided the input to the table to maintain nacelle to fan concentricity as thermal and thrust loads displaced the strut-mounted fan. This unique design required extensive analysis and verification testing to ensure the safety of the fan model, propulsion simulator drive rig, and facility, along with experimental consistency of acoustic data obtained while using the RAN system. Initial testing was used to optimize the positioning system and resulted in concentricity errors of +/- 0.0031 in. in the horizontal direction and +0.0035/-0.0013 in, in the vertical direction. As a result of successful testing, the RAN system will be transitioned into other acoustic research programs at NASA Glenn Research Center.

  11. Two-dimensional poroelastic acoustical foam shape design for absorption coefficient maximization by topology optimization method.

    PubMed

    Lee, Joong Seok; Kim, Yoon Young; Kim, Jung Soo; Kang, Yeon June

    2008-04-01

    Optimal shape design of a two-dimensional poroelastic acoustical foam is formulated as a topology optimization problem. For a poroelastic acoustical system consisting of an air region and a poroelastic foam region, two different physical regions are continuously changed in an iterative design process. To automatically account for the moving interfaces between two regions, we propose a new unified model to analyze the whole poroelastic acoustical foam system with one set of governing equations; Biot's equations are modified with a material property interpolation from a topology optimization method. With the unified analysis model, we carry out two-dimensional optimal shape design of a poroelastic acoustical foam by a gradient-based topology optimization setting. The specific objective is the maximization of the absorption coefficient in low and middle ranges of frequencies with different amounts of a poroelastic material. The performances of the obtained shapes are compared with those of well-known wedge shapes, and the improvement of absorption is physically interpreted.

  12. Design of a semi-implantable hearing device for direct acoustic cochlear stimulation.

    PubMed

    Bernhard, Hans; Stieger, Christof; Perriard, Yves

    2011-02-01

    A new hearing therapy based on direct acoustic cochlear stimulation was developed for the treatment of severe to profound mixed hearing loss. The device efficacy was validated in an initial clinical trial with four patients. This semi-implantable investigational device consists of an externally worn audio processor, a percutaneous connector, and an implantable microactuator. The actuator is placed in the mastoid bone, right behind the external auditory canal. It generates vibrations that are directly coupled to the inner ear fluids and that, therefore, bypass the external and the middle ear. The system is able to provide an equivalent sound pressure level of 125 dB over the frequency range between 125 and 8000 Hz. The hermetically sealed actuator is designed to provide maximal output power by keeping its dimensions small enough to enable implantation. A network model is used to simulate the dynamic characteristics of the actuator to adjust its transfer function to the characteristics of the middle ear. The geometry of the different actuator components is optimized using finite-element modeling.

  13. Acoustical features of two Mayan monuments at Chichen Itza: Accident or design?

    NASA Astrophysics Data System (ADS)

    Lubman, David

    2002-11-01

    Chichen Itza dominated the early postclassic Maya world, ca. 900-1200 C.E. Two of its colossal monuments, the Great Ball Court and the temple of Kukulkan, reflect the sophisticated, hybrid culture of a Mexicanized Maya civilization. The architecture seems intended for ceremony and ritual drama. Deducing ritual practices will advance the understanding of a lost civilization, but what took place there is largely unknown. Perhaps acoustical science can add value. Unexpected and unusual acoustical features can be interpreted as intriguing clues or irrelevant accidents. Acoustical advocates believe that, when combined with an understanding of the Maya worldview, acoustical features can provide unique insights into how the Maya designed and used theater spaces. At Chichen Itza's monuments, sound reinforcement features improve rulers and priests ability to address large crowds, and Ball Court whispering galleries permit speech communication over unexpectedly large distances. Handclaps at Kukulkan stimulate chirps that mimic a revered bird (''Kukul''), thus reinforcing cultic beliefs. A ball striking playing field wall stimulates flutter echoes at the Great Ball Court; their strength and duration arguably had dramatic, mythic, and practical significance. Interpretations of the possible mythic, magic, and political significance of sound phenomena at these Maya monuments strongly suggests intentional design.

  14. Two stage low noise advanced technology fan. 1: Aerodynamic, structural, and acoustic design

    NASA Technical Reports Server (NTRS)

    Messenger, H. E.; Ruschak, J. T.; Sofrin, T. G.

    1974-01-01

    A two-stage fan was designed to reduce noise 20 db below current requirements. The first-stage rotor has a design tip speed of 365.8 m/sec and a hub/tip ratio of 0.4. The fan was designed to deliver a pressure ratio of 1.9 with an adiabatic efficiency of 85.3 percent at a specific inlet corrected flow of 209.2kg/sec/sq m. Noise reduction devices include acoustically treated casing walls, a flowpath exit acoustic splitter, a translating centerbody sonic inlet device, widely spaced blade rows, and the proper ratio of blades and vanes. Multiple-circular-arc rotor airfoils, resettable stators, split outer casings, and capability to go to close blade-row spacing are also included.

  15. Experimental validation of systematically designed acoustic hyperbolic meta material slab exhibiting negative refraction

    NASA Astrophysics Data System (ADS)

    Christiansen, Rasmus E.; Sigmund, Ole

    2016-09-01

    This Letter reports on the experimental validation of a two-dimensional acoustic hyperbolic metamaterial slab optimized to exhibit negative refractive behavior. The slab was designed using a topology optimization based systematic design method allowing for tailoring the refractive behavior. The experimental results confirm the predicted refractive capability as well as the predicted transmission at an interface. The study simultaneously provides an estimate of the attenuation inside the slab stemming from the boundary layer effects—insight which can be utilized in the further design of the metamaterial slabs. The capability of tailoring the refractive behavior opens possibilities for different applications. For instance, a slab exhibiting zero refraction across a wide angular range is capable of funneling acoustic energy through it, while a material exhibiting the negative refractive behavior across a wide angular range provides lensing and collimating capabilities.

  16. Investigation of acoustic emission and surface treatment to improve tool materials and metal forming process

    NASA Astrophysics Data System (ADS)

    Cao, Deming

    Silicon nitride and WC-Co cermet tools are used for metal forming processes including extrusion and drawing. These materials are used to make tool dies which are exposed to deformation caused by friction and wear. Surface treatments such as ion implantation, laser blazing and coating have been found to improve surface properties, to optimize tribological behavior between the metal and die, as well as to extend service life of the tool dies. Early detection and continuous monitoring processes by non destructive testing (NDT) methods are needed in order to ensure the functionality of the wear process and extend the tool service life. Acoustic emission is one of the promising NDT methods for this application. The surface treatment chosen for this investigation was ion implantation. Three types of wear resistant materials with and without surface treatment were selected for this project; silicon nitride and two tungsten carbides (6% Cobalt and 10% Cobalt). This investigation was conducted using a pin-on-disk device for wear/friction tests of the selected materials with lubrication and/or without lubrication against both a stainless steel disk and an aluminum disk. The acoustic emissions generated during the experiments were recorded and analyzed. The results of this investigation showed that the ion implantation improved the tribological properties of the materials and reduced acoustic emission and coefficient of friction. A linear relationship between the average amplitude of the acoustic emission and the coefficient of friction of the tested materials was found. The investigation demonstrated that the acoustic emission method could be used to monitor the wear/friction processes.

  17. Rotating rake design for unique measurement of fan-generated spinning acoustic modes

    NASA Technical Reports Server (NTRS)

    Konno, Kevin E.; Hausmann, Clifford R.

    1993-01-01

    In light of the current emphasis on noise reduction in subsonic aircraft design, NASA has been actively studying the source of and propagation of noise generated by subsonic fan engines. NASA/LeRC has developed and tested a unique method of accurately measuring these spinning acoustic modes generated by an experimental fan. This mode measuring method is based on the use of a rotating microphone rake. Testing was conducted in the 9 x 15 Low-speed Wind Tunnel. The rotating rake was tested with the Advanced Ducted Propeller (ADP) model. This memorandum discusses the design and performance of the motor/drive system for the fan-synchronized rotating acoustic rake. This novel motor/drive design approach is now being adapted for additional acoustic mode studies in new test rigs as baseline data for the future design of active noise control for subsonic fan engines. Included in this memorandum are the research requirements, motor/drive specifications, test performance results, and a description of the controls and software involved.

  18. Effects of inescapable stress and treatment with pyridostigmine bromide on plasma butyrylcholinesterase and the acoustic startle response in rats.

    PubMed

    Servatius, R J; Ottenweller, J E; Guo, W; Beldowicz, D; Zhu, G; Natelson, B H

    2000-05-01

    Pyridostigmine bromide (PB) is a reversible, peripherally active inhibitor of acetylcholinesterase (AChE) activity, and is recommended by the military as a pretreatment against potential nerve gas exposure. Recent evidence suggests that exposure to inescapable stressors allows PB to cross the blood-brain barrier, and thereby affect central AChE activity in mice. Here, we evaluated the functional impact of a stress/PB treatment interaction on acoustic startle responding and plasma butyrylcholinesterase (BuChE) activity in male Sprague-Dawley rats. To model the treatment protocol used by the military, PB was delivered in the drinking water of rats for 7 consecutive days. The morning after the start of PB treatment, and for the next 6 days, half the rats were exposed to 1 h of supine restraint stress. We therefore employed a 2 x 2 (stress x PB treatment) between-groups design. Exposure to supine stress alone induced a persistent decrease in plasma BuChE activity. Further decreases in BuChE activity were not observed in rats exposed to supine restraint and PB treatment. Exposure to stress also induced an exaggerated startle response, evident on the last day of stress and 24 h after stressor cessation. Treatment with PB alone produced an exaggerated startle response over the same time period, albeit to a lesser degree. Although treatment with PB concurrent with stress did not produce further changes in either BuChE activity or acoustic startle responding, stress-induced alterations in drinking behavior (and thereby the dose of PB ingested) may have affected these results. Persistent stress-induced reductions in BuChE activity may increase the risk of adverse reactions to cholinomimetics.

  19. Acoustic resonators for noise control in enclosures: Modelling, design and optimization

    NASA Astrophysics Data System (ADS)

    Yu, Ganghua

    This work systematically investigates the acoustic interaction between an enclosure and resonators, and establishes systematic design tools based upon the interaction theory to optimize the physical characteristics and the locations of resonators. A general theoretical model is first established to predict the acoustic performance of multiple resonators placed in an acoustic enclosure of arbitrary shape. Analytical solutions for the sound pressure inside the enclosure are obtained when a single resonator is installed, which provide insight into the physics of the acoustic interaction between the enclosure and resonators. The theoretical model is experimentally validated, showing the effectiveness and reliability of the theoretical model. Using the validated acoustic interaction model and the analytical solutions, the internal resistance of a resonator is optimized to improve its performance in a frequency band enclosing acoustic resonances. An energy reduction index is defined to conduct the optimization. The dual process of the energy dissipation and radiation of the resonator is quantified. Optimal resistance and its physical effect on the enclosure-resonator interaction are numerically evaluated and categorized in terms of frequency bandwidths. Predictions on the resonator performance are confirmed by experiments. Comparisons with existing models based on different optimization criteria are also performed. It is shown that the proposed model serves as an effective design tool to determine the optimal internal-resistance of the resonator in a chosen frequency band. Due to the multi-modal coupling, the resonator performance is also affected by its location besides its physical characteristics. When multiple resonators are used, the mutual interaction among resonators leads to the requirement of a systematic optimization tool to determine their locations. In the present work, different optimization methodologies are explored. These include a sequential design

  20. Acoustic characteristics and the design of two-layered soundproof plates

    NASA Astrophysics Data System (ADS)

    Chonan, S.; Kugo, Y.

    1989-03-01

    This paper presents exact solutions for the coincidence frequency and the sound transmission loss of two-layered infinite plates excited by a plane acoustic wave. The problem is studied based on the two-dimensional elasticity theory wih the use of the Lame potential functions . A simple design method for a soundproof sheet with high transmission loss and high coincidence frequency is presented and illustrated with some examples. The results obtained are also compared with those from the thick plate theory.

  1. Design and Evaluation of Complex Moving HIFU Treatment Protocols

    NASA Astrophysics Data System (ADS)

    Kargl, Steven G.; Andrew, Marilee A.; Kaczkowski, Peter J.; Brayman, Andrew A.; Crum, Lawrence A.

    2005-03-01

    The use of moving high-intensity focused ultrasound (HIFU) treatment protocols is of interest in achieving efficient formation of large-volume thermal lesions in tissue. Judicious protocol design is critical in order to avoid collateral damage to healthy tissues outside the treatment zone. A KZK-BHTE model, extended to simulate multiple, moving scans in tissue, is used to investigate protocol design considerations. Prediction and experimental observations are presented which 1) validate the model, 2) illustrate how to assess the effects of acoustic nonlinearity, and 3) demonstrate how to assess and control collateral damage such as prefocal lesion formation and lesion formation resulting from thermal conduction without direct HIFU exposure. Experimental data consist of linear and circular scan protocols delivered over a range of exposure regimes in ex vivo bovine liver.

  2. Multi-acoustic lens design methodology for a low cost C-scan photoacoustic imaging camera

    NASA Astrophysics Data System (ADS)

    Chinni, Bhargava; Han, Zichao; Brown, Nicholas; Vallejo, Pedro; Jacobs, Tess; Knox, Wayne; Dogra, Vikram; Rao, Navalgund

    2016-03-01

    We have designed and implemented a novel acoustic lens based focusing technology into a prototype photoacoustic imaging camera. All photoacoustically generated waves from laser exposed absorbers within a small volume get focused simultaneously by the lens onto an image plane. We use a multi-element ultrasound transducer array to capture the focused photoacoustic signals. Acoustic lens eliminates the need for expensive data acquisition hardware systems, is faster compared to electronic focusing and enables real-time image reconstruction. Using this photoacoustic imaging camera, we have imaged more than 150 several centimeter size ex-vivo human prostate, kidney and thyroid specimens with a millimeter resolution for cancer detection. In this paper, we share our lens design strategy and how we evaluate the resulting quality metrics (on and off axis point spread function, depth of field and modulation transfer function) through simulation. An advanced toolbox in MATLAB was adapted and used for simulating a two-dimensional gridded model that incorporates realistic photoacoustic signal generation and acoustic wave propagation through the lens with medium properties defined on each grid point. Two dimensional point spread functions have been generated and compared with experiments to demonstrate the utility of our design strategy. Finally we present results from work in progress on the use of two lens system aimed at further improving some of the quality metrics of our system.

  3. Spectrally Efficient Underwater Acoustic Communications: Channel Characterization and Design Aspects for OFDM

    NASA Astrophysics Data System (ADS)

    Radosevic, Andreja

    In this dissertation, we consider design aspects of spectrally efficient underwater acoustic (UWA) communications. In particular, we first focus on statistical characterization and capacity evaluation of shallow water acoustic communications channels. Wideband single-carrier and multi-carrier probe signals are employed during the Kauai Acoustic Communications MURI 2008 (KAM08) and 2011 (KAM11) experiments, to measure the time-varying channel response, and to estimate its statistical properties and capacity that play an important role in the design of spectrally efficient communication systems. Besides the capacity analysis for unconstrained inputs, we determine new bounds on the achievable information rate for discrete-time Gaussian channels with inter-symbol interference and independent and uniformly distributed channel input symbols drawn from finite-order modulation alphabets. Specifically, we derived new bounds on the achievable rates for sparse channels with long memory. Furthermore, we explore design aspects of adaptive modulation based on orthogonal frequency division multiplexing (OFDM) for UWA communications, and study its performance using real-time at-sea experiments. Lastly, we investigate a channel estimation (CE) method for improving the spectral efficiency of UWA communications. Specifically, we determine the performance of a selective decision directed (DD) CE method for UWA OFDM-based communications.

  4. Effect of acoustically assisted treatments on vitamins, antioxidant activity, organic acids and drying kinetics of pineapple.

    PubMed

    Rodríguez, Óscar; Gomes, Wesley; Rodrigues, Sueli; Fernandes, Fabiano A N

    2017-03-01

    The effects of the application of an acoustically assisted treatment on the vitamins (C, B1, B2, B3, and B5), the antioxidant activity (DPPH, FRAP), the polyphenol and flavonoid contents, the organic acid contents (citric and malic) and drying kinetics of pineapple (Ananas comosus var. Perola) have been studied. Treatments were carried out using two different soaking media: distilled water and pineapple juice at 30°C during 10, 20 and 30min without and with acoustic assistance (23.2W/L). After treatment, samples were dried at 60°C and 0.5m/s during 8h. The quality parameters were determined in untreated, treated, and treated-dried samples. The acoustic assistance promoted an increment of vitamins B1, B2, B3 and B5, total flavonoid and malic acid contents, and a reduction of vitamin C, total polyphenol content, antioxidant activity and citric acid content in treated samples. However, in all treated-dried samples the final content of those quality parameters was higher than the observed in the untreated dried sample.

  5. Wind-tunnel acoustic results of two rotor models with several tip designs

    NASA Technical Reports Server (NTRS)

    Martin, R. M.; Connor, A. B.

    1986-01-01

    A three-phase research program has been undertaken to study the acoustic signals due to the aerodynamic interaction of rotorcraft main rotors and tail rotors. During the first phase, two different rotor models with several interchangeable tips were tested in the Langley 4- by 7-Meter Tunnel on the U.S. Army rotor model system. An extensive acoustic data base was acquired, with special emphasis on blade-vortex interaction (BVI) noise. The details of the experimental procedure, acoustic data acquisition, and reduction are documented. The overall sound pressure level (OASPL) of the high-twist rotor systems is relatively insensitive to flight speed but generally increases with rotor tip-path-plane angle. The OASPL of the high-twist rotors is dominated by acoustic energy in the low-frequency harmonics. The OASPL of the low-twist rotor systems shows more dependence on flight speed than the high-twist rotors, in addition to being quite sensitive to tip-path-plane angle. An integrated band-limited sound pressure level, limited by 500 to 3000 Hz, is a useful metric to quantify the occurrence of BVI noise. The OASPL of the low-twist rotors is strongly influenced by the band-limited sound levels, indicating that the blade-vortex impulsive noise is a dominant noise source for this rotor design. The midfrequency acoustic levels for both rotors show a very strong dependence on rotor tip-path-plane angle. The tip-path-plane angle at which the maximum midfrequency sound level occurs consistently decreases with increasing flight speed. The maximum midfrequency sound level measured at a given location is constant regardless of the flight speed.

  6. Acoustical Testing Laboratory Developed to Support the Low-Noise Design of Microgravity Space Flight Hardware

    NASA Technical Reports Server (NTRS)

    Cooper, Beth A.

    2001-01-01

    The NASA John H. Glenn Research Center at Lewis Field has designed and constructed an Acoustical Testing Laboratory to support the low-noise design of microgravity space flight hardware. This new laboratory will provide acoustic emissions testing and noise control services for a variety of customers, particularly for microgravity space flight hardware that must meet International Space Station limits on noise emissions. These limits have been imposed by the space station to support hearing conservation, speech communication, and safety goals as well as to prevent noise-induced vibrations that could impact microgravity research data. The Acoustical Testing Laboratory consists of a 23 by 27 by 20 ft (height) convertible hemi/anechoic chamber and separate sound-attenuating test support enclosure. Absorptive 34-in. fiberglass wedges in the test chamber provide an anechoic environment down to 100 Hz. A spring-isolated floor system affords vibration isolation above 3 Hz. These criteria, along with very low design background levels, will enable the acquisition of accurate and repeatable acoustical measurements on test articles, up to a full space station rack in size, that produce very little noise. Removable floor wedges will allow the test chamber to operate in either a hemi/anechoic or anechoic configuration, depending on the size of the test article and the specific test being conducted. The test support enclosure functions as a control room during normal operations but, alternatively, may be used as a noise-control enclosure for test articles that require the operation of noise-generating test support equipment.

  7. Design and Analysis of Advanced Materials in a Thermal/Acoustic Environment. Delivery Order 0007: Volume 1 - Structural Health Monitoring

    DTIC Science & Technology

    2010-03-01

    AFRL-RB-WP-TR-2010-3028 DESIGN AND ANALYSIS OF ADVANCED MATERIALS IN A THERMAL/ACOUSTIC ENVIRONMENT Delivery Order 0007: Volume 1‒Structural...Final 15 July 2005 – 30 March 2010 4. TITLE AND SUBTITLE DESIGN AND ANALYSIS OF ADVANCED MATERIALS IN A THERMAL/ACOUSTIC ENVIRONMENT Delivery...ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Wright State University Department of Mechanical and Materials

  8. Acoustic and social design of schools-ways to improve the school listening environment

    NASA Astrophysics Data System (ADS)

    Hagen, Mechthild

    2005-04-01

    Results of noise research indicate that communication, and as a result, teaching, learning and the social atmosphere are impeded by noise in schools. The development of strategies to reduce noise levels has often not been effective. A more promising approach seems to be to pro-actively support the ability to listen and to understand. The presentation describes the approach to an acoustic and social school design developed and explored within the project ``GanzOhrSein'' by the Education Department of the Ludwig-Maximilians-University of Munich. The scope includes an analysis of the current ``school soundscape,'' an introduction to the concept of the project to improve individual listening abilities and the conditions for listening, as well as practical examples and relevant research results. We conclude that an acoustic school design should combine acoustic changes in classrooms with educational activities to support listening at schools and thus contribute to improving individual learning conditions and to reducing stress on both pupils and teachers.

  9. Measurement of Insertion Loss of an Acoustic Treatment in the Presence of Additional Uncorrelated Sound Sources

    NASA Technical Reports Server (NTRS)

    Klos, Jacob; Palumbo, Daniel L.

    2003-01-01

    A method to intended for measurement of the insertion loss of an acoustic treatment applied to an aircraft fuselage in-situ is documented in this paper. Using this method, the performance of a treatment applied to a limited portion of an aircraft fuselage can be assessed even though the untreated fuselage also radiates into the cabin, corrupting the intensity measurement. This corrupting noise in the intensity measurement incoherent with the panel vibration of interest is removed by correlating the intensity to reference transducers such as accelerometers. Insertion loss of the acoustic treatments is estimated from the ratio of correlated intensity measurements with and without a treatment applied. In the case of turbulent boundary layer excitation of the fuselage, this technique can be used to assess the performance of noise control methods without requiring treatment of the entire fuselage. Several experimental studies and numerical simulations have been conducted, and results from three case studies are documented in this paper. Conclusions are drawn about the use of this method to study aircraft sidewall treatments.

  10. Design and Implementation of an Acoustic X-ray Detector to Measure the LCLS Beam Energy

    SciTech Connect

    Loos, Jennifer L.; /San Jose State U. /SLAC

    2010-08-25

    On April 11, 2009, first light was seen from LCLS. The present apparatus being used to measure the x-ray beam energy is the Total Energy Sensor which uses a suite of thermal sensors. Another device is needed to cross-check the energy measurements. This new diagnostic tool utilizes radiation acoustic phenomena to determine the x-ray beam energy. A target is hit by the x-rays from the beam, and a voltage is generated in two piezoelectric sensors attached to the target in response to the consequent deformation. Once the voltage is known, the power can be obtained. Thermal sensors will also be attached to the target for calibration purposes. Material selection and design were based on: durability, ultra-high vacuum compatibility, safety and thermal properties. The target material was also chosen for its acoustic properties which were determined from tests using a frequency generator and laser. Initial tests suggest the device will function as anticipated.

  11. Towards multifocal ultrasonic neural stimulation II: design considerations for an acoustic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Naor, Omer; Hertzberg, Yoni; Zemel, Esther; Kimmel, Eitan; Shoham, Shy

    2012-04-01

    Ultrasound waves, widely used as a non-invasive diagnostic modality, were recently shown to stimulate neuronal activity. Functionally meaningful stimulation, as is required in order to form a unified percept, requires the dynamic generation of simultaneous stimulation patterns. In this paper, we examine the general feasibility and properties of an acoustic retinal prosthesis, a new vision restoration strategy that will combine ultrasonic neuro-stimulation and ultrasonic field sculpting technology towards non-invasive artificial stimulation of surviving neurons in a degenerating retina. We explain the conceptual framework for such a device, study its feasibility in an in vivo ultrasonic retinal stimulation study and discuss the associated design considerations and tradeoffs. Finally, we simulate and experimentally validate a new holographic method—the angular spectrum-GSW—for efficient generation of uniform and accurate continuous ultrasound patterns. This method provides a powerful, flexible solution to the problem of projecting complex acoustic images onto structures like the retina.

  12. Design and Analyses of High Aspect Ratio Nozzles for Distributed Propulsion Acoustic Measurements

    NASA Technical Reports Server (NTRS)

    Dippold, Vance F., III

    2016-01-01

    A series of three convergent round-to-rectangular high-aspect ratio nozzles were designed for acoustics measurements. The nozzles have exit area aspect ratios of 8:1, 12:1, and 16:1. With septa inserts, these nozzles will mimic an array of distributed propulsion system nozzles, as found on hybrid wing-body aircraft concepts. Analyses were performed for the three nozzle designs and showed that the flow through the nozzles was free of separated flow and shocks. The exit flow was mostly uniform with the exception of a pair of vortices at each span-wise end of the nozzle.

  13. Comparison of STRUCTURAL-ACOUSTIC Control Designs on AN Active Composite Panel

    NASA Astrophysics Data System (ADS)

    BINGHAM, B.; ATALLA, M. J.; HAGOOD, N. W.

    2001-07-01

    This work presents a comparison of three technologies for structural-acoustic control that, while prevalent in the literature, had not been compared on a single structure. The comparison is generalizable because the techniques are implemented on a panel structure representative of a more complex structure (e.g., an aircraft fuselage, a submarine vehicle hull, a satellite payload shroud, etc.). The test-bed used for this comparison is a carbon-fiber composite panel manufactured with embedded active fiber composite actuators. Since such integrated structures constitute a continued avenue of research, the manufacturing and performance of this structure is illustrated. The design of the test-bed is guided by an effort to achieve a dynamic response similar to a single panel in a typical aircraft or rotorcraft fuselage.Existing active control architectures for broadband acoustic radiation reduction are compared both analytically and experimentally on a representative structure to quantify the capabilities and limitations of the existing control methodologies. Specifically, three broad categories of control are compared: classical feedback (rate feedback), optimal feedback (linear quadratic Gaussian), and adaptive feedforward control (x -filtered least mean square). The control architectures implemented during this study are all single-input/single-output in order to allow a fair comparison of the issues involved in the design, as well as the use and performance of each approach. Both the vibration and the acoustic performance are recorded for each experiment under equivalent conditions to allow a generalizable comparison. Experimental results lead to conclusions pertaining to the application of active structural-based control to improve the acoustic performance of more complex structures.

  14. Mechanical design and vibro-acoustic testing of ultrathin carbon foils for a spacecraft instrument

    SciTech Connect

    Bernardin, John D; Baca, Allen G

    2009-01-01

    IBEX-Hi is an electrostatic analyzer spacecraft instrument designed to measure the energy and flux distribution of energetic neutral atoms (ENAs) emanating from the interaction zone between the Earth's solar system and the Milky Way galaxy. A key element to this electro-optic instrument is an array of fourteen carbon foils that are used to ionize the ENAs. The foils are comprised of an ultrathin (50-100 {angstrom} thick) layer of carbon suspended across the surface of an electroformed Nickel wire screen, which in turn is held taught by a metal frame holder. The electro formed orthogonal screen has square wire elements, 12.7 {micro}m thick, with a pitch of 131.1 wires/cm. Each foil holder has an open aperture approximately 5 cm by 2.5 cm. Designing and implementing foil holders with such a large surface area has not been attempted for spaceflight in the past and has proven to be extremely challenging. The delicate carbon foils are subject to fatigue failure from the large acoustic and vibration loads that they will be exposed to during launch of the spacecraft. This paper describes the evolution of the foil holder design from previous space instrument applications to a flight-like IBEX-Hi prototype. Vibro-acoustic qualification tests of the IBEX-Hi prototype instrument and the resulting failure of several foils are summarized. This is followed by a discussion of iterative foil holder design modifications and laser vibrometer modal testing to support future fatigue failure analyses, along with additional acoustic testing of the IBEX-Hi prototype instrument. The results of these design and testing activities are merged and the resulting flight-like foil holder assembly is proposed.

  15. Acoustic pressure wound therapy in the treatment of stage II pressure ulcers.

    PubMed

    Thomas, Raenell

    2008-11-01

    Pressure ulcers are localized skin injuries secondary to unrelieved pressure or friction. Patients with immobility issues are at increased risk for developing pressure ulcers. In 2004, stricter federal regulations for prevention and treatment of pressure ulcers in institutional settings--eg, long-term care facilities--were introduced. Effective, low-cost treatments for pressure ulcers are needed; acoustic pressure wound therapy (APWT), a noncontact, low-frequency, therapeutic ultrasound system, is one option. A retrospective case series of six long-term care patients (two men and one woman, age range 61 to 92 years), each with one Stage II pressure ulcer, is presented. Acoustic pressure wound therapy was provided as an adjunct to standard treatment that included balsam of Peru/castor oil/trypsin ointment, hydrogel, hydrocolloid dressings, silver dressings, and offloading. Outcomes (days to healing) were determined through changes in wound dimensions. Study participants each received APWT for 3 to 4 minutes three to four times weekly. In four of the six wounds, the average number of days to healing was 22. One of the two remaining patients discontinued treatment at 95% healed; treatment for the sixth patient was ongoing due to hospitalization that delayed APWT. In a long-term care setting, APWT added to standard of care may accelerate healing of Stage II pressure ulcers.

  16. Improving the design of acoustic and midwater trawl surveys through stratification, with an application to Lake Michigan prey fishes

    USGS Publications Warehouse

    Adams, J.V.; Argyle, R.L.; Fleischer, G.W.; Curtis, G.L.; Stickel, R.G.

    2006-01-01

    Reliable estimates of fish biomass are vital to the management of aquatic ecosystems and their associated fisheries. Acoustic and midwater trawl surveys are an efficient sampling method for estimating fish biomass in large bodies of water. To improve the precision of biomass estimates from combined acoustic and midwater trawl surveys, sampling effort should be optimally allocated within each stage of the survey design. Based on information collected during fish surveys, we developed an approach to improve the design of combined acoustic and midwater trawl surveys through stratification. Geographic strata for acoustic surveying and depth strata for midwater trawling were defined using neighbor-restricted cluster analysis, and the optimal allocation of sampling effort for each was then determined. As an example, we applied this survey stratification approach to data from lakewide acoustic and midwater trawl surveys of Lake Michigan prey fishes. Precision of biomass estimates from surveys with and without geographic stratification was compared through resampling. Use of geographic stratification with optimal sampling allocation reduced the variance of Lake Michigan acoustic biomass estimates by 77%. Stratification and optimal allocation at each stage of an acoustic and midwater trawl survey should serve to reduce the variance of the resulting biomass estimates.

  17. Design and Analyses of High Aspect Ratio Nozzles for Distributed Propulsion Acoustic Measurements

    NASA Technical Reports Server (NTRS)

    Dippold, Vance F., III

    2016-01-01

    A series of three convergent, round-to-rectangular high aspect ratio (HAR) nozzles were designed for acoustic testing at the NASA Glenn Research Center Nozzle Acoustic Test Rig (NATR). The HAR nozzles had exit area aspect ratios of 8:1, 12:1, and 16:1. The nozzles were designed to mimic a distributed propulsion system array with a slot nozzle. The nozzle designs were screened using Reynolds-Averaged Navier-Stokes (RANS) simulations. In addition to meeting the geometric constraints required for testing in the NATR, the HAR nozzles were designed to be free of flow features that would produce unwanted noise (e.g., flow separations) and to have uniform flow at the nozzle exit. Multiple methods were used to generate HAR nozzle designs. The final HAR nozzle designs were generated in segments using a computer code that parameterized each segment. RANS screening simulations showed that intermediate nozzle designs suffered flow separation, a normal shockwave at the nozzle exit (caused by an aerodynamic throat produced by boundary layer growth), and non-uniform flow at the nozzle exit. The RANS simulations showed that the final HAR nozzle designs were free of flow separations, but were not entirely successful at producing a fully uniform flow at the nozzle exit. The final designs suffered a pair of counter-rotating vortices along the outboard walls of the nozzle. The 16:1 aspect ratio HAR nozzle had the least uniform flow at the exit plane; the 8:1 aspect ratio HAR nozzles had a fairly uniform flow at the nozzle exit plane.

  18. Design and Instrumentation of a Measurement and Calibration System for an Acoustic Telemetry System

    SciTech Connect

    Deng, Zhiqun; Weiland, Mark A.; Carlson, Thomas J.; Eppard, M. B.

    2010-03-31

    The Juvenile Salmon Acoustic Telemetry System (JSATS) is an active sensing technology developed by Portland District, the U.S. Army Corps of Engineers for detecting and tracking small fish. It is used at hydroelectric projects and in the laboratory for evaluating behavior and survival of juvenile salmonids migrating through the Federal Columbia River Power System to the Pacific Ocean. It provides critical data for salmon protection and development of more “fish-friendly” hydroelectric facilities. The objective of this study was to design and build a measurement and calibration system for evaluating the JSATS component, because the JSATS requires comprehensive acceptance and performance testing in a controlled environment before it is deployed in the field. The system consists of a reference transducer, a water test tank lined with anechoic material, a motion control unit, a reference receiver, a signal conditioner and amplifier unit, a data acquisition board, MATLAB control and analysis interface, and a computer. The fully integrated system has been evaluated successfully at various simulated distances and using different encoded signals at frequencies within the bandwidth of the JSATS transmitter. It provides accurate acoustic mapping capability in a controlled environment and automates the process that allows real-time measurements and evaluation of the piezoelectric transducers, sensors, or the acoustic fields. The measurement and calibration system has been in use since 2009 for acceptance and performance testing of, and further improvements to, the JSATS.

  19. Design and instrumentation of a measurement and calibration system for an acoustic telemetry system.

    PubMed

    Deng, Zhiqun; Weiland, Mark; Carlson, Thomas; Eppard, M Brad

    2010-01-01

    The Juvenile Salmon Acoustic Telemetry System (JSATS) is an active sensing technology developed by the U.S. Army Corps of Engineers, Portland District, for detecting and tracking small fish. It is used primarily for evaluating behavior and survival of juvenile salmonids migrating through the Federal Columbia River Power System to the Pacific Ocean. It provides critical data for salmon protection and development of more "fish-friendly" hydroelectric facilities. The objective of this study was to design and build a Measurement and Calibration System (MCS) for evaluating the JSATS components, because the JSATS requires comprehensive acceptance and performance testing in a controlled environment before it is deployed in the field. The MCS consists of a reference transducer, a water test tank lined with anechoic material, a motion control unit, a reference receiver, a signal conditioner and amplifier unit, a data acquisition board, MATLAB control and analysis interface, and a computer. The fully integrated MCS has been evaluated successfully at various simulated distances and using different encoded signals at frequencies within the bandwidth of the JSATS transmitter. The MCS provides accurate acoustic mapping capability in a controlled environment and automates the process that allows real-time measurements and evaluation of the piezoelectric transducers, sensors, or the acoustic fields. The MCS has been in use since 2009 for acceptance and performance testing of, and further improvements to, the JSATS.

  20. Characterization of Retrogression and Re-Aging Heat Treatment of AA7075-T6 Using Nonlinear Acoustics and Eddy Current

    SciTech Connect

    Ananthula, Rajeshwar; Ko, Ray T.; Sathish, Shamachary; Blodgett, Mark

    2004-02-26

    Nonlinear acoustic parameter and eddy current methods have been utilized to characterize the heat treatment process of retrogression and re-aging of aluminum 7075-T6. The results of nonlinear acoustic parameter measurements show two distinct peaks at 30 minutes and 45 minutes of retrogression time. The phase of the through-thickness eddy current signal shows a minimum at 42 minutes of retrogression time. Application of combined methods for identifying the optimized properties in the material is discussed.

  1. A normalized wave number variation parameter for acoustic black hole design.

    PubMed

    Feurtado, Philip A; Conlon, Stephen C; Semperlotti, Fabio

    2014-08-01

    In recent years, the concept of the Acoustic Black Hole has been developed as an efficient passive, lightweight absorber of bending waves in plates and beams. Theory predicts greater absorption for a higher thickness taper power. However, a higher taper power also increases the violation of an underlying theory smoothness assumption. This paper explores the effects of high taper power on the reflection coefficient and spatial change in wave number and discusses the normalized wave number variation as a spatial design parameter for performance, assessment, and optimization.

  2. Enhanced sensitive love wave surface acoustic wave sensor designed for immunoassay formats.

    PubMed

    Puiu, Mihaela; Gurban, Ana-Maria; Rotariu, Lucian; Brajnicov, Simona; Viespe, Cristian; Bala, Camelia

    2015-05-05

    We report a Love wave surface acoustic wave (LW-SAW) immunosensor designed for the detection of high molecular weight targets in liquid samples, amenable also for low molecular targets in surface competition assays. We implemented a label-free interaction protocol similar to other surface plasmon resonance bioassays having the advantage of requiring reduced time analysis. The fabricated LW-SAW sensor supports the detection of the target in the nanomolar range, and can be ultimately incorporated in portable devices, suitable for point-of-care testing (POCT) applications.

  3. Optimization of Capacitive Acoustic Resonant Sensor Using Numerical Simulation and Design of Experiment

    PubMed Central

    Haque, Rubaiyet Iftekharul; Loussert, Christophe; Sergent, Michelle; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    Optimization of the acoustic resonant sensor requires a clear understanding of how the output responses of the sensor are affected by the variation of different factors. During this work, output responses of a capacitive acoustic transducer, such as membrane displacement, quality factor, and capacitance variation, are considered to evaluate the sensor design. The six device parameters taken into consideration are membrane radius, backplate radius, cavity height, air gap, membrane tension, and membrane thickness. The effects of factors on the output responses of the transducer are investigated using an integrated methodology that combines numerical simulation and design of experiments (DOE). A series of numerical experiments are conducted to obtain output responses for different combinations of device parameters using finite element methods (FEM). Response surface method is used to identify the significant factors and to develop the empirical models for the output responses. Finally, these results are utilized to calculate the optimum device parameters using multi-criteria optimization with desirability function. Thereafter, the validating experiments are designed and deployed using the numerical simulation to crosscheck the responses. PMID:25894937

  4. Acoustic Performance Of New Designs Of Traffic Noise Barriers: Full Scale Tests

    NASA Astrophysics Data System (ADS)

    Watts, G. R.; Crombie, D. H.; Hothersall, D. C.

    1994-10-01

    Full scale tests of acoustical performance are reported on a range of promising traffic noise barrier shapes which had previously been identified by mathematical and scale modelling work. The designs chosen for testing were T-shaped, multiple edge barriers and double barriers. A test facility was established at the Transport Research Laboratory (TRL) in order to examine effectiveness under full scale conditions. This consisted of a 20 m length of noise barrier with interchangeable barrier panels, a large flat asphalt surface and a transportable speaker system capable of sufficient output to represent typical traffic noise. Screening performance was measured up to 80 m behind the barriers over a flat grassland area and at heights above the ground of 1·5 and 4·5 m. It was concluded that the average increase in acoustic screening of 2 m high T-shaped, multiple edge and double barriers compared with a simple plane reflecting barrier of identical overall height ranged from 1·4 to 3·6dB(A) depending on detailed design. It was suggested that a full scale test of a promising design should be carried out at a suitable highway location in order to validate fully these test results.

  5. Design of a Hydro-Turbine Blade for Acoustic and Performance Validation Studies

    NASA Astrophysics Data System (ADS)

    Johnson, E.; Barone, M.

    2011-12-01

    To meet the growing, global energy demands governments and industry have recently begun to focus on marine hydrokinetic (MHK) devices as an additional form of power generation. Water turbines have become a popular design choice since they are able to leverage experience from the decades-old wind industry in the hope of decreasing time-to-market. However, the difference in environments poses challenges that need to be addressed. In particular, little research has addressed the acoustic effects of common aerofoils in a marine setting. This has both a potential impact on marine life and may cause early fatigue by exciting new structural modes. An initial blade design is presented, which has been used to begin characterization of any structural and acoustic issues that may arise from a direct one-to-one swap of wind technologies into MHK devices. The blade was optimized for performance using blade-element momentum theory while requiring that it not exceed the allowable stress under a specified extreme operating design condition. This limited the maximum power generated, while ensuring a realizable blade. A stress analysis within ANSYS was performed to validate the structural integrity of the design. Additionally, predictions of the radiated noise from the MHK rotor will be made using boundary element modeling based on flow results from ANSYS CFX, a computational fluid dynamics (CFD) code. The FEA and CFD results demonstrate good comparison to the expected design. Determining a range for the anticipated noise produced from a MHK turbine provides a look at the environmental impact these devices will have. Future efforts will focus on the design constraints noise generation places on MHK devices.

  6. 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.

  7. Achieving acoustical performance with fire safe products

    NASA Astrophysics Data System (ADS)

    Fritz, Thomas

    2005-09-01

    Recent serious fires in North and South America have pointed out potential problems with attempts to improve acoustical performance in building spaces at the expense of using acoustical treatments that may have poor performance in fire situations. Foam plastic products, sometimes not designed for exposed use in buildings, can ignite quickly and spread fire rapidly throughout a building space, resulting in fire victims being trapped within the building or not being afforded the needed safe egress time. There are ways of achieving equivalent and even superior acoustical performance without sacrificing fire safety. Acoustical products are available which can add comparable or superior acoustical treatment without the fire hazard associated with exposed foam plastic materials. This presentation is a review of the U.S. code requirements of interior finish materials, the various types of fire tests that are applied to these products, and a discussion of the achievable fire and acoustical performance.

  8. Design guidelines for avoiding thermo-acoustic oscillations in helium piping systems

    SciTech Connect

    Gupta, Prabhat Kumar; Rabehl, Roger

    2015-04-02

    Thermo-acoustic oscillations are a commonly observed phenomenon in helium cryogenic systems, especially in tubes connecting hot and cold areas. The open ends of these tubes are connected to the lower temperature (typically at 4.5 K), and the closed ends of these tubes are connected to the high temperature (300 K). Cryogenic instrumentation installations provide ideal conditions for these oscillations to occur due to the steep temperature gradient along the tubing. These oscillations create errors in measurements as well as an undesirable heat load to the system. The work presented here develops engineering guidelines to design oscillation-free helium piping. This work also studies the effect of different piping inserts and shows how the proper geometrical combinations have to be chosen to avoid thermo-acoustic oscillations. The effect of an 80 K intercept is also studied and shows that thermo-oscillations can be dampened by placing the intercept at an appropriate location. As a result, the design of helium piping based on the present work is also verified with the experimental results available in open literature.

  9. Design guidelines for avoiding thermo-acoustic oscillations in helium piping systems

    DOE PAGES

    Gupta, Prabhat Kumar; Rabehl, Roger

    2015-04-02

    Thermo-acoustic oscillations are a commonly observed phenomenon in helium cryogenic systems, especially in tubes connecting hot and cold areas. The open ends of these tubes are connected to the lower temperature (typically at 4.5 K), and the closed ends of these tubes are connected to the high temperature (300 K). Cryogenic instrumentation installations provide ideal conditions for these oscillations to occur due to the steep temperature gradient along the tubing. These oscillations create errors in measurements as well as an undesirable heat load to the system. The work presented here develops engineering guidelines to design oscillation-free helium piping. This workmore » also studies the effect of different piping inserts and shows how the proper geometrical combinations have to be chosen to avoid thermo-acoustic oscillations. The effect of an 80 K intercept is also studied and shows that thermo-oscillations can be dampened by placing the intercept at an appropriate location. As a result, the design of helium piping based on the present work is also verified with the experimental results available in open literature.« less

  10. Application of acoustic surface wave filter-beam lead component technology to deep space multimission hardware design

    NASA Technical Reports Server (NTRS)

    Kermode, A. W.; Boreham, J. F.

    1974-01-01

    This paper discusses the utilization of acoustic surface wave filters, beam lead components, and thin film metallized ceramic substrate technology as applied to the design of deep space, long-life, multimission transponder. The specific design to be presented is for a second mixer local oscillator module, operating at frequencies as high as 249 MHz.

  11. The design and flight test of an engine inlet bulk acoustic liner

    NASA Technical Reports Server (NTRS)

    Lester, H. C.; Preisser, J. S.; Parrott, T. L.

    1983-01-01

    This paper summarizes the design, fabrication and flight evaluation of a Kevlar acoustic liner configuration for a JT15D turbofan engine. The liner was designed to suppress, by a measurable amount, a dominant (13,0) BPF tone. This tone or spinning mode was produced for research purposes by installing 41 circumferentially distributed small diameter rods upstream of the 28 fan blades. Duct liner attenuations calculated by a finite element procedure were compared to far field power (insertion) losses deduced from flight data. The finite element program modeled the variable geometry of the JT15D inlet and used a uniform flow with a boundary layer roll-off to model the inlet flow field. Calculated liner losses were generally conservative. That is, measured far field power losses were generally greater than attenuations calculated by the finite element computer program.

  12. Design and Experimental Validation of a USBL Underwater Acoustic Positioning System

    PubMed Central

    Reis, Joel; Morgado, Marco; Batista, Pedro; Oliveira, Paulo; Silvestre, Carlos

    2016-01-01

    This paper presents the steps for developing a low-cost POrtableNavigation Tool for Underwater Scenarios (PONTUS) to be used as a localization device for subsea targets. PONTUS consists of an integrated ultra-short baseline acoustic positioning system aided by an inertial navigation system. Built on a practical design, it can be mounted on an underwater robotic vehicle or be operated by a scuba diver. It also features a graphical user interface that provides information on the tracking of the designated target, in addition to some details on the physical properties inside PONTUS. A full disclosure of the architecture of the tool is first presented, followed by thorough technical descriptions of the hardware components ensemble and the software development process. A series of experiments was carried out to validate the developed prototype, and the results are presented herein, which allow assessing its overall performance. PMID:27649181

  13. Design and Experimental Validation of a USBL Underwater Acoustic Positioning System.

    PubMed

    Reis, Joel; Morgado, Marco; Batista, Pedro; Oliveira, Paulo; Silvestre, Carlos

    2016-09-14

    This paper presents the steps for developing a low-cost POrtableNavigation Tool for Underwater Scenarios (PONTUS) to be used as a localization device for subsea targets. PONTUS consists of an integrated ultra-short baseline acoustic positioning system aided by an inertial navigation system. Built on a practical design, it can be mounted on an underwater robotic vehicle or be operated by a scuba diver. It also features a graphical user interface that provides information on the tracking of the designated target, in addition to some details on the physical properties inside PONTUS. A full disclosure of the architecture of the tool is first presented, followed by thorough technical descriptions of the hardware components ensemble and the software development process. A series of experiments was carried out to validate the developed prototype, and the results are presented herein, which allow assessing its overall performance.

  14. Evaluation of the Acoustic Measurement Capability of the NASA Langley V/STOL Wind Tunnel Open Test Section with Acoustically Absorbent Ceiling and Floor Treatments

    NASA Technical Reports Server (NTRS)

    Theobald, M. A.

    1978-01-01

    The single source location used for helicopter model studies was utilized in a study to determine the distances and directions upstream of the model accurate at which measurements of the direct acoustic field could be obtained. The method used was to measure the decrease of sound pressure levels with distance from a noise source and thereby determine the Hall radius as a function of frequency and direction. Test arrangements and procedures are described. Graphs show the normalized sound pressure level versus distance curves for the glass fiber floor treatment and for the foam floor treatment.

  15. An experimental study of the effects of water repellant treatment on the acoustic properties of Kevlar

    NASA Technical Reports Server (NTRS)

    Smith, C. D.; Parrott, T. L.

    1978-01-01

    The treatment consisted of immersing samples of Kevlar in a solution of distilled water and Zepel. The samples were then drained, dried in a circulating over, and cured. Flow resistance tests showed approximately one percent decrease in flow resistance of the samples. Also there was a density increase of about three percent. It was found that the treatment caused a change in the texture of the samples. There were significant changes in the acoustic properties of the treated Kevlar over the frequency range 0.5 to 3.5 kHz. In general it was found that the propagation constant and characteristic impedance increased with increasing frequency. The real and imaginary components of the propagation constant for the treated Kevlar exhibited a decrease of 8 to 12 percent relative to that for the untreated Kevlar at the higher frequencies. The magnitude of the reactance component of the characteristic impedance decreased by about 40 percent at the higher frequencies.

  16. Preliminary vibration, acoustic, and shock design and test criteria for components on the Lightweight External Tank (LWT)

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The Space Shuttle LWT is divided into zones and subzones. Zones are designated primarily to assist in determining the applicable specifications. A subzone (general Specification) is available for use when the location of the component is known but component design and weight are not well defined. When the location, weight, and mounting configuration of the component are known, specifications for appropriate subzone weight ranges are available. Along with the specifications are vibration, acoustic, shock, transportation, handling, and acceptance test requirements and procedures. A method of selecting applicable vibration, acoustic, and shock specifications is presented.

  17. Acoustic specifications for the design of jet engine test facilities on an airbase

    SciTech Connect

    Strumpf, F.M.

    1982-01-01

    The use of engine run up test arrangements was common in Israeli air-bases since the forties, when engines for the Mustang, Mosquito, Harward and other propellor powered planes were used. The era of jet engine propulsion boosted the noise levels, and the use of fighters with afterburners in the new engines of the 80's brought it up to unbearable levels. Thus, the growth of the Israeli Air Force demanded the use of efficient noise suppression devices. These were divided into engine run-up noise suppressors, and aircraft noise suppessors (Hush Houses). For both of the bove ground arrangements, acoustic specifications had to be given. They were, as well as design goals for the manufacturers, also needed to restrict noise levels on the air-base as well as its surroundings. The acoustic specifications discussed are based on measured data, and permitted noise levels in the homes on the base being as far as 2500 meters from the engine exhaust silencer. For the special air-base discussed, various criteria were tested, including US Military Specifications, none of which were acceptable, and a special specification was therefore prepared.

  18. Design of a robust underwater acoustic communication system over multipath fading channels

    NASA Astrophysics Data System (ADS)

    Kim, Jangeun; Shim, Taebo

    2012-11-01

    Due to the surface and bottom constraints of the underwater acoustic channel (UAC) in shallow waters, multipath fading occurs and causes degradation of the signal for the UAC system. To overcome these problems, a robust underwater acoustic communication system was designed over multipath fading channels by employing both decision feedback equalization with the RLS algorithm and convolutional coding with interleaving+shuffling block data sequence. The dual use of these two methods simultaneously can reduce the intersymbol interference (ISI) and the adjacent bit and burst errors. The system will retransmit the same signal if the system fails to estimate the channel due to severe multipath fading. To verify the performance of the system, the transmission of an image was tested using a 524,288bit gray-scaled image through the multipath fading channel. The test results showed that the number of bit errors was reduced from 86,824 to 5,106 when the reference SNR was 12 dB.

  19. Design considerations for the acoustic emission testing of large composite specimens

    NASA Astrophysics Data System (ADS)

    Scholey, Jonathan J.; Wilcox, Paul D.; Wisnom, Michael R.; Friswell, Mike I.

    2009-03-01

    Acoustic emission (AE) testing is a sensitive technique capable of detecting many types of defect with a sparse sensor array making it an attractive structural health monitoring technology. The widespread application of the technology is limited by a lack of predictive modelling and in part, the lack of quantitative source characteristics. The vast majority of current laboratory AE testing is conducted on small coupons which cannot be used to generate quantitative source characteristics since reflected wave energy from the specimen edges influences the received waveforms. An alternative approach is to test on large specimens where the modal properties of propagating waves can be examined with no influence from reflected wave energy. However, the design and testing of large specimens is not trivial. The work in this paper discusses the design of large fibre reinforced composite (FRC) specimens which are suitable for making quantitative source measurements. The design considerations include the minimum plate dimensions and placement of sensors. A novel technique, referred to as the location-time plot technique, is described which links propagation characteristics, specimen dimensions and sensor locations to map the dispersion of elastic waves in plates. The technique is demonstrated in the design of a simple AE experiment on a highly anisotropic plate. The technique is then used in the design of a practical AE testing arrangement for monitoring delamination from artificial defects in a large FRC plate. Experimental waveforms, recorded using this AE testing arrangement, are presented and are shown to be in agreement with the location-time plot technique.

  20. A debugging system for azimuthally acoustic logging tools based on modular and hierarchical design ideas

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Ju, X. D.; Lu, J. Q.; Men, B. Y.

    2016-08-01

    On the basis of modular and hierarchical design ideas, this study presents a debugging system for an azimuthally sensitive acoustic bond tool (AABT). The debugging system includes three parts: a personal computer (PC), embedded front-end machine and function expansion boards. Modular and hierarchical design ideas are conducted in all design and debug processes. The PC communicates with the front-end machine via the Internet, and the front-end machine and function expansion boards connect each other by the extended parallel bus. In this method, the three parts of the debugging system form stable and high-speed data communication. This study not only introduces the system-level debugging and sub-system level debugging of the tool but also the debugging of the analogue signal processing board, which is important and greatly used in logging tools. Experiments illustrate that the debugging system can greatly improve AABT verification and calibration efficiency and that, board-level debugging can examine and improve analogue signal processing boards. The design thinking is clear and the design structure is reasonable, thus making it easy to extend and upgrade the debugging system.

  1. In-flight acoustic results from an advanced-design propeller at Mach numbers to 0.8

    NASA Technical Reports Server (NTRS)

    Mackall, K. G.; Lasagna, P. L.; Walsh, K.; Dittmar, J. H.

    1982-01-01

    Acoustic data for the advanced-design SR-3 propeller at Mach numbers to 0.8 and helical tip Mach numbers to 1.14 are presented. Several advanced-design propellers, previously tested in wind tunnels at the Lewis Research Center, are being tested in flight at the Dryden Flight Research Facility. The flight-test propellers are mounted on a pylon on the top of the fuselage of a JetStar airplane. Instrumentation provides near-field acoustic data for the SR-3. Acoustic data for the SR-3 propeller at Mach numbers up to 0.8, for propeller helical tip Mach numbers up to 1.14, and comparison of wind tunnel to flight data are included. Flowfield profiles measured in the area adjacent to the propeller are also included.

  2. Design, characterization, and experimental use of the second generation MEMS acoustic emission device

    NASA Astrophysics Data System (ADS)

    Ozevin, Didem; Greve, David W.; Oppenheim, Irving J.; Pessiki, Stephen

    2005-05-01

    We describe the design, fabrication, testing and application (in structural experiments) of our 2004 (second generation) MEMS device, designed for acoustic emission sensing based upon experiments with our 2002 (first generation) device. Both devices feature a suite of resonant-type transducers in the frequency range between 100 kHz and 1 MHz. The 2002 device was designed to operate in an evacuated housing because of high squeeze film damping, as confirmed in our earlier experiments. In additional studies involving the 2002 device, experimental simulation of acoustic emissions in a steel plate, using pencil lead break or ball impact loading, showed that the transducers in the frequency range of 100 kHz-500 kHz presented clearer output signals than the transducers with frequencies higher than 500 kHz. Using the knowledge gained from the 2002 device, we designed and fabricated our second generation device in 2004 using the multi-user polysilicon surface micromachining (MUMPs) process. The 2004 device has 7 independent capacitive type transducers, compared to 18 independent transducers in the 2002 device, including 6 piston type transducers in the frequency range of 100 kHz to 500 kHz and 1 piston type transducer at 1 MHz to capture high frequency information. Piston type transducers developed in our research have two uncoupled modes so that twofold information can be acquired from a single transducer. In addition, the piston shape helps to reduce residual stress effect of surface micromachining process. The center to center distance between etch holes in the vibrating plate was reduced from 30 μm to 13 μm, in order to reduce squeeze film damping. As a result, the Q factor under atmospheric pressure for the 100 kHz transducer was increased to 2.37 from 0.18, and therefore the vacuum housing has been eliminated from the 2004 device. Sensitivities of transducers were also increased, by enlarging transducer area, in order to capture significant small amplitude acoustic

  3. Design Guidelines for Avoiding Thermo-Acoustic Oscillations in Helium Piping Systems

    SciTech Connect

    Gupta, Prabhat Kumar; Rabehl, Roger

    2014-01-01

    Thermo-acoustic oscillations are a commonly observed phenomenon in helium cryogenic systems, especially in tubes connecting hot and cold areas. The open ends of these tubes are connected to the lower temperature (typically at 4.2 K), and the closed ends of these tubes are connected to the high temperature (300K). Cryogenic instrumentation installations provide ideal conditions for these oscillations to occur due to the steep temperature gradient along the tubing. These oscillations create errors in measurements as well as an undesirable heat load to the system. The work presented here develops engineering guidelines to design oscillation-free helium piping. This work also studies the effect of different piping inserts and shows how the proper geometrical combinations have to be chosen to avoid thermo-oscillations. The effect of an 80 K intercept is also studied and shows that thermo-oscillations can be dampened by placing the intercept at an appropriate location.

  4. SU-E-CAMPUS-T-02: Exploring Radiation Acoustics CT Dosimeter Design Aspects for Proton Therapy

    SciTech Connect

    Alsanea, F; Moskvin, V; Stantz, K

    2014-06-15

    Purpose: Investigate the design aspects and imaging dose capabilities of the Radiation Acoustics Computed Tomography (RA CT) dosimeter for Proton induced acoustics, with the objective to characterize a pulsed pencil proton beam. The focus includes scanner geometry, transducer array, and transducer bandwidth on image quality. Methods: The geometry of the dosimeter is a cylindrical water phantom (length 40cm, radius 15cm) with 71 ultrasound transducers placed along the length and end of the cylinder to achieve a weighted set of projections with spherical sampling. A 3D filtered backprojection algorithm was used to reconstruct the dosimetric images and compared to MC dose distribution. First, 3D Monte Carlo (MC) Dose distributions for proton beam energies (range of 12cm, 16cm, 20cm, and 27cm) were used to simulate the acoustic pressure signal within this scanner for a pulsed proton beam of 1.8x107 protons, with a pulse width of 1 microsecond and a rise time of 0.1 microseconds. Dose comparison within the Bragg peak and distal edge were compared to MC analysis, where the integrated Gaussian was used to locate the 50% dose of the distal edge. To evaluate spatial fidelity, a set of point sources within the scanner field of view (15×15×15cm3) were simulated implementing a low-pass bandwidth response function (0 to 1MHz) equivalent to a multiple frequency transducer array, and the FWHM of the point-spread-function determined. Results: From the reconstructed images, RACT and MC range values are within 0.5mm, and the average variation of the dose within the Bragg peak are within 2%. The spatial resolution tracked with transducer bandwidth and projection angle sampling, and can be kept at 1.5mm. Conclusion: This design is ready for fabrication to start acquiring measurements. The 15 cm FOV is an optimum size for imaging dosimetry. Currently, simulations comparing transducer sensitivity, bandwidth, and proton beam parameters are being evaluated to assess signal-to-noise.

  5. Development of a model to assess acoustic treatments to reduce railway noise

    NASA Astrophysics Data System (ADS)

    Jeong, H.; Squicciarini, G.; Thompson, D. J.; Ryue, J.

    2016-09-01

    Porous materials have recently been used in absorptive treatments around railway tracks to reduce noise emissions. To investigate the effect of porous materials, a finite element model has been developed. 2D models for porous materials have been considered either as an equivalent fluid or as a poroelastic material based on the Biot theory. The two models have been validated and compared with each other to check the effect of the skeleton vibration. The poroelastic FE model has been coupled with a 2D acoustic boundary element model for use in railway applications. The results show that it may be necessary to include the frame vibration, especially at low frequencies where a frame resonance occurs. A method for the characterization of porous materials is also discussed. From this it is shown that the elastic properties of the material determine the resonance frequency and the magnitude.

  6. Design and Development of a Deep Acoustic Lining for the 40-by 80-Foot Wind Tunnel Test Section

    NASA Technical Reports Server (NTRS)

    Soderman, Paul T.; Schmitz, Fredric H.; Allen, Christopher S.; Jaeger, Stephen M.; Sacco, Joe N.; Mosher, Marianne; Hayes, Julie A.

    2002-01-01

    The work described in this report has made effective use of design teams to build a state-of-the-art anechoic wind-tunnel facility. Many potential design solutions were evaluated using engineering analysis, and computational tools. Design alternatives were then evaluated using specially developed testing techniques, Large-scale coupon testing was then performed to develop confidence that the preferred design would meet the acoustic, aerodynamic, and structural objectives of the project. Finally, designs were frozen and the final product was installed in the wind tunnel. The result of this technically ambitious project has been the creation of a unique acoustic wind tunnel. Its large test section (39 ft x 79 ft x SO ft), potentially near-anechoic environment, and medium subsonic speed capability (M = 0.45) will support a full range of aeroacoustic testing-from rotorcraft and other vertical takeoff and landing aircraft to the take-off/landing configurations of both subsonic and supersonic transports.

  7. TU-G-210-03: Acoustic Simulations in Transcranial MRgFUS: Treatment Prediction and Analysis

    SciTech Connect

    Vyas, U.

    2015-06-15

    Modeling can play a vital role in predicting, optimizing and analyzing the results of therapeutic ultrasound treatments. Simulating the propagating acoustic beam in various targeted regions of the body allows for the prediction of the resulting power deposition and temperature profiles. In this session we will apply various modeling approaches to breast, abdominal organ and brain treatments. Of particular interest is the effectiveness of procedures for correcting for phase aberrations caused by intervening irregular tissues, such as the skull in transcranial applications or inhomogeneous breast tissues. Also described are methods to compensate for motion in targeted abdominal organs such as the liver or kidney. Douglas Christensen – Modeling for Breast and Brain HIFU Treatment Planning Tobias Preusser – TRANS-FUSIMO - An Integrative Approach to Model-Based Treatment Planning of Liver FUS Urvi Vyas – Acoustic Simulations in Transcranial MRgFUS: Treatment Prediction and Analysis Learning Objectives: Understand the role of acoustic beam modeling for predicting the effectiveness of therapeutic ultrasound treatments. Apply acoustic modeling to specific breast, liver, kidney and transcranial anatomies. Determine how to obtain appropriate acoustic modeling parameters from clinical images. Understand the separate role of absorption and scattering in energy delivery to tissues. See how organ motion can be compensated for in ultrasound therapies. Compare simulated data with clinical temperature measurements in transcranial applications. Supported by NIH R01 HL172787 and R01 EB013433 (DC); EU Seventh Framework Programme (FP7/2007-2013) under 270186 (FUSIMO) and 611889 (TRANS-FUSIMO)(TP); and P01 CA159992, GE, FUSF and InSightec (UV)

  8. Efficient modeling of flat and homogeneous acoustic treatments for vibroacoustic finite element analysis. Finite size correction by image sources

    NASA Astrophysics Data System (ADS)

    Alimonti, L.; Atalla, N.

    2017-02-01

    This work is concerned with the hybrid finite element-transfer matrix methodology recently proposed by the authors. The main assumption behind this hybrid method consists in neglecting the actual finite lateral extent of the acoustic treatment. Although a substantial increase of the computational efficiency can be achieved, the effect of the reflected field (i.e. finite size effects) may be sometimes important, preventing the hybrid model from giving quantitative meaningful results. For this reason, a correction to account for wave reflections at the lateral boundaries of the acoustic treatment is sought. It is shown in the present paper that the image source method can be successfully employed to retrieve such finite size effects. Indeed, such methodology is known to be effective when the response of the system is a smooth function of the frequency, like in the case of highly dissipative acoustic treatments. The main concern of this paper is to assess accuracy and feasibility of the image source method in the context of acoustic treatments modeling. Numerical examples show that the performance of the standard hybrid model can be substantially improved by the proposed correction without deteriorating excessively the computational efficiency.

  9. Analytical and numerical calculations of optimum design frequency for focused ultrasound therapy and acoustic radiation force.

    PubMed

    Ergün, A Sanlı

    2011-10-01

    Focused ultrasound therapy relies on acoustic power absorption by tissue. The stronger the absorption the higher the temperature increase is. However, strong acoustic absorption also means faster attenuation and limited penetration depth. Hence, there is a trade-off between heat generation efficacy and penetration depth. In this paper, we formulated the acoustic power absorption as a function of frequency and attenuation coefficient, and defined two figures of merit to measure the power absorption: spatial peak of the acoustic power absorption density, and the acoustic power absorbed within the focal area. Then, we derived "rule of thumb" expressions for the optimum frequencies that maximized these figures of merit given the target depth and homogeneous tissue type. We also formulated a method to calculate the optimum frequency for inhomogeneous tissue given the tissue composition for situations where the tissue structure can be assumed to be made of parallel layers of homogeneous tissue. We checked the validity of the rules using linear acoustic field simulations. For a one-dimensional array of 4cm acoustic aperture, and for a two-dimensional array of 4×4cm(2) acoustic aperture, we found that the power absorbed within the focal area is maximized at 0.86MHz, and 0.79MHz, respectively, when the target depth is 4cm in muscle tissue. The rules on the other hand predicted the optimum frequencies for acoustic power absorption as 0.9MHz and 0.86MHz, respectively for the 1D and 2D array case, which are within 6% and 9% of the field simulation results. Because radiation force generated by an acoustic wave in a lossy propagation medium is approximately proportional to the acoustic power absorption, these rules can be used to maximize acoustic radiation force generated in tissue as well.

  10. Modeling Attitude Variance in Small UAS’s for Acoustic Signature Simplification Using Experimental Design in a Hardware-in-the-Loop Simulation

    DTIC Science & Technology

    2015-03-26

    MODELING ATTITUDE VARIANCE IN SMALL UAS’S FOR ACOUSTIC SIGNATURE SIMPLIFICATION USING EXPERIMENTAL...and is not subject to copyright protection in the United States. AFIT-ENS-MS-15-M-110 MODELING ATTITUDE VARIANCE IN SMALL UAS’S FOR ACOUSTIC ...IN SMALL UAS’S FOR ACOUSTIC SIGNATURE SIMPLIFICATION USING EXPERIMENTAL DESIGN IN A HARDWARE-IN-THE-LOOP SIMULATION Mitchell N. Gillespie

  11. Rational design of nanomaterials for water treatment

    NASA Astrophysics Data System (ADS)

    Li, Renyuan; Zhang, Lianbin; Wang, Peng

    2015-10-01

    The ever-increasing human demand for safe and clean water is gradually pushing conventional water treatment technologies to their limits. It is now a popular perception that the solutions to the existing and future water challenges will hinge upon further developments in nanomaterial sciences. The concept of rational design emphasizes on `design-for-purpose' and it necessitates a scientifically clear problem definition to initiate the nanomaterial design. The field of rational design of nanomaterials for water treatment has experienced a significant growth in the past decade and is poised to make its contribution in creating advanced next-generation water treatment technologies in the years to come. Within the water treatment context, this review offers a comprehensive and in-depth overview of the latest progress in rational design, synthesis and applications of nanomaterials in adsorption, chemical oxidation and reduction reactions, membrane-based separation, oil-water separation, and synergistic multifunctional all-in-one nanomaterials/nanodevices. Special attention is paid to the chemical concepts related to nanomaterial design throughout the review.

  12. Reliable data storage system design and implementation for acoustic logging while drilling

    NASA Astrophysics Data System (ADS)

    Hao, Xiaolong; Ju, Xiaodong; Wu, Xiling; Lu, Junqiang; Men, Baiyong; Yao, Yongchao; Liu, Dong

    2016-12-01

    Owing to the limitations of real-time transmission, reliable downhole data storage and fast ground reading have become key technologies in developing tools for acoustic logging while drilling (LWD). In order to improve the reliability of the downhole storage system in conditions of high temperature, intensive shake and periodic power supply, improvements were made in terms of hardware and software. In hardware, we integrated the storage system and data acquisition control module into one circuit board, to reduce the complexity of the storage process, by adopting the controller combination of digital signal processor and field programmable gate array. In software, we developed a systematic management strategy for reliable storage. Multiple-backup independent storage was employed to increase the data redundancy. A traditional error checking and correction (ECC) algorithm was improved and we embedded the calculated ECC code into all management data and waveform data. A real-time storage algorithm for arbitrary length data was designed to actively preserve the storage scene and ensure the independence of the stored data. The recovery procedure of management data was optimized to realize reliable self-recovery. A new bad block management idea of static block replacement and dynamic page mark was proposed to make the period of data acquisition and storage more balanced. In addition, we developed a portable ground data reading module based on a new reliable high speed bus to Ethernet interface to achieve fast reading of the logging data. Experiments have shown that this system can work stably below 155 °C with a periodic power supply. The effective ground data reading rate reaches 1.375 Mbps with 99.7% one-time success rate at room temperature. This work has high practical application significance in improving the reliability and field efficiency of acoustic LWD tools.

  13. Risk of a second cancer from scattered radiation in acoustic neuroma treatment

    NASA Astrophysics Data System (ADS)

    Yoon, Myonggeun; Lee, Hyunho; Sung, Jiwon; Shin, Dongoh; Park, Sungho; Chung, Weon Kuu; Jahng, Geon-Ho; Kim, Dong Wook

    2014-06-01

    The present study aimed to compare the risk of a secondary cancer from scattered and leakage doses in patients receiving intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS). Four acoustic neuroma patients were treated with IMRT, VMAT, or SRS. Their excess relative risk (ERR), excess absolute risk (EAR), and lifetime attributable risk (LAR) of a secondary cancer were estimated using the corresponding secondary doses measured at various organs by using radio-photoluminescence glass dosimeters (RPLGD) placed inside a humanoid phantom. When a prescription dose was delivered in the planning target volume of the 4 patients, the average organ equivalent doses (OED) at the thyroid, lung, liver, bowel, bladder, prostate (or ovary), and rectum were 14.6, 1.7, 0.9, 0.8, 0.6, 0.6, and 0.6 cGy, respectively, for IMRT whereas they were 19.1, 1.8, 2.0, 0.6, 0.4, 0.4, and 0.4 cGy, respectively, for VMAT, and 22.8, 4.6, 1.4, 0.7, 0.5, 0.5, and 0.5 cGy, respectively, for SRS. The OED decreased as the distance from the primary beam increased. The thyroid received the highest OED compared to other organs. A lifetime attributable risk evaluation estimated that more than 0.03% of acoustic neuroma (AN) patients would get radiation-induced cancer within 20 years of receiving radiation therapy. The organ with the highest radiation-induced cancer risk after radiation treatment for AN was the thyroid. We found that the LAR could be increased by the transmitted dose from the primary beam. No modality-specific difference in radiation-induced cancer risk was observed in our study.

  14. A new electromagnetic acoustic transducer design for generating torsional guided wave modes for pipe inspections

    NASA Astrophysics Data System (ADS)

    Hill, Samuel; Dixon, Steve; Sri Harsha Reddy, K.; Rajagopal, Prabhu; Balasubramaniam, Krishnan

    2017-02-01

    Guided waves inspection is a well-established method for the long-range ultrasonic inspection of pipes. Guided waves, used in a pulse-echo arrangement, can inspect a large range of the pipe from a single point as the pipe structure carries the waves over a large distance due to the relatively low attenuation of the wave modes. However, the complexity of the dispersion characteristics of these pipe guided wave modes are well known, and can lead to diffculty interpreting the obtained results. The torsional family of guided wave modes are generally considered to have much simpler dispersion characteristics; especially the fundamental T(0,1) mode, which is nominally non-dispersive, making it particularly useful for guided wave inspection. Torsional waves have been generated by a circumferential ring of transducers to approximate an axi-symmetric load to excite this T(0, 1) mode. Presented here is a new design of Electromagnetic Acoustic Transducer (EMAT) that can generate a T(0, 1) as a single transducer, rather than a circumferential array of transducers that all need to be excited in order to generate an axisymmetric force. The EMAT consists of a periodic permanent magnet array and a single meander coil, meaning that the excitation of the torsional mode is greatly simplified. The design parameters of this new EMAT are explored, and the ability to detect notch defects on a pipe is demonstrated.

  15. Design factors of intravascular dual frequency transducers for super-harmonic contrast imaging and acoustic angiography.

    PubMed

    Ma, Jianguo; Martin, K Heath; Li, Yang; Dayton, Paul A; Shung, K Kirk; Zhou, Qifa; Jiang, Xiaoning

    2015-05-07

    Imaging of coronary vasa vasorum may lead to assessment of the vulnerable plaque development in diagnosis of atherosclerosis diseases. Dual frequency transducers capable of detection of microbubble super-harmonics have shown promise as a new contrast-enhanced intravascular ultrasound (CE-IVUS) platform with the capability of vasa vasorum imaging. Contrast-to-tissue ratio (CTR) in CE-IVUS imaging can be closely associated with low frequency transmitter performance. In this paper, transducer designs encompassing different transducer layouts, transmitting frequencies, and transducer materials are compared for optimization of imaging performance. In the layout selection, the stacked configuration showed superior super-harmonic imaging compared with the interleaved configuration. In the transmitter frequency selection, a decrease in frequency from 6.5 MHz to 5 MHz resulted in an increase of CTR from 15 dB to 22 dB when receiving frequency was kept constant at 30 MHz. In the material selection, the dual frequency transducer with the lead magnesium niobate-lead titanate (PMN-PT) 1-3 composite transmitter yielded higher axial resolution compared to single crystal transmitters (70 μm compared to 150 μm pulse length). These comparisons provide guidelines for the design of intravascular acoustic angiography transducers.

  16. Optimal design and evaluation criteria for acoustic emission pulse signature analysis

    NASA Technical Reports Server (NTRS)

    Houghton, J. R.; Townsend, M. A.; Packman, P. F.

    1977-01-01

    Successful pulse recording and evaluation is strongly dependent on the instrumentation system selected and the method of analyzing the pulse signature. The paper studies system design, signal analysis techniques, and interdependences with a view toward defining optimal approaches to pulse signal analysis. For this purpose, the instrumentation system is modeled, and analytical pulses, representative of the types of acoustic emissions to be distinguished are passed through the system. Particular attention is given to comparing frequency spectrum analysis and deconvolution referred to as time domain reconstruction of the pulse or pulse train. The possibility of optimal transducer-filter system parameters is investigated. Deconvolution of a pulse is shown to be a superior approach for transient pulse analysis. Reshaping of a transducer output back to the original input pulse is possible and gives an accurate representation of the generating pulse in the time domain. Any definable transducer and filter system can be used for measurement of pulses by means of the deconvolution method. Selection of design variables for general usage is discussed.

  17. Design factors of intravascular dual frequency transducers for super-harmonic contrast imaging and acoustic angiography

    NASA Astrophysics Data System (ADS)

    Ma, Jianguo; Martin, K. Heath; Li, Yang; Dayton, Paul A.; Shung, K. Kirk; Zhou, Qifa; Jiang, Xiaoning

    2015-05-01

    Imaging of coronary vasa vasorum may lead to assessment of the vulnerable plaque development in diagnosis of atherosclerosis diseases. Dual frequency transducers capable of detection of microbubble super-harmonics have shown promise as a new contrast-enhanced intravascular ultrasound (CE-IVUS) platform with the capability of vasa vasorum imaging. Contrast-to-tissue ratio (CTR) in CE-IVUS imaging can be closely associated with low frequency transmitter performance. In this paper, transducer designs encompassing different transducer layouts, transmitting frequencies, and transducer materials are compared for optimization of imaging performance. In the layout selection, the stacked configuration showed superior super-harmonic imaging compared with the interleaved configuration. In the transmitter frequency selection, a decrease in frequency from 6.5 MHz to 5 MHz resulted in an increase of CTR from 15 dB to 22 dB when receiving frequency was kept constant at 30 MHz. In the material selection, the dual frequency transducer with the lead magnesium niobate-lead titanate (PMN-PT) 1-3 composite transmitter yielded higher axial resolution compared to single crystal transmitters (70 μm compared to 150 μm pulse length). These comparisons provide guidelines for the design of intravascular acoustic angiography transducers.

  18. Design factors of intravascular dual frequency transducers for super-harmonic contrast imaging and acoustic angiography

    PubMed Central

    Ma, Jianguo; Martin, K. Heath; Li, Yang; Dayton, Paul A.; Shung, K. Kirk; Zhou, Qifa; Jiang, Xiaoning

    2015-01-01

    Imaging of coronary vasa vasorum may lead to assessment of the vulnerable plaque development in diagnosis of atherosclerosis diseases. Dual frequency transducers capable of detection of microbubble super-harmonics have shown promise as a new contrast-enhanced intravascular ultrasound (CE-IVUS) platform with the capability of vasa vasorum imaging. Contrast-to-tissue ratio (CTR) in CE-IVUS imaging can be closely associated with the low frequency transmitter performance. In this paper, transducer designs encompassing different transducer layouts, transmitting frequencies, and transducer materials are compared for optimization of imaging performance. In the layout selection, the stacked configuration showed superior super-harmonic imaging compared with the interleaved configuration. In the transmitter frequency selection, a decrease in frequency from 6.5 MHz to 5 MHz resulted in an increase of CTR from 15 dB to 22 dB when receiving frequency was kept constant at 30 MHz. In the material selection, the dual frequency transducer with the lead magnesium niobate-lead titanate (PMN-PT) 1-3 composite transmitter yielded higher axial resolution compared to single crystal transmitters (70 μm compared to 150 μm pulse length). These comparisons provide guidelines for design of intravascular acoustic angiography transducers. PMID:25856384

  19. Towards a reference cavitating vessel Part III—design and acoustic pressure characterization of a multi-frequency sonoreactor

    NASA Astrophysics Data System (ADS)

    Wang, Lian; Memoli, Gianluca; Hodnett, Mark; Butterworth, Ian; Sarno, Dan; Zeqiri, Bajram

    2015-08-01

    A multi-frequency cavitation vessel (RV-multi) has been commissioned at the National Physical Laboratory (NPL, UK), with the aim of establishing a standard source of acoustic cavitation in water, with reference to which details of the cavitation process can be studied and cavitation measurement techniques evaluated. The vessel is a cylindrical cavity with a maximum capacity up to 17 L, and is designed to work at six frequency ranges, from 21 kHz to 136 kHz, under controlled temperature conditions. This paper discusses the design of RV-multi and reports experiments carried out to establish the reproducibility of the acoustic pressure field established within the vessel and its operating envelope, including sensitivity to aspects such as water depth and temperature. The acoustic field distribution was determined along the radial and depth directions within the vessel using a miniature hydrophone, for two input voltage levels under low power transducer excitation conditions (e.g. below the cavitation threshold). Particular care was taken in determining peak acoustic pressure locations, as these are critical for accompanying cavitation studies. Perturbations of the vessel by the measuring hydrophone were also monitored with a bottom-mounted pressure sensor.

  20. A new sparse design method on phased array-based acoustic emission sensor for partial discharge detection

    NASA Astrophysics Data System (ADS)

    Xie, Qing; Cheng, Shuyi; Lü, Fangcheng; Li, Yanqing

    2014-03-01

    The acoustic detecting performance of a partial discharge (PD) ultrasonic sensor array can be improved by increasing the number of array elements. However, it will increase the complexity and cost of the PD detection system. Therefore, a sparse sensor with an optimization design can be chosen to ensure good acoustic performance. In this paper, first, a quantitative method is proposed for evaluating the acoustic performance of a square PD ultrasonic array sensor. Second, a method of sparse design is presented to combine the evaluation method with the chaotic monkey algorithm. Third, an optimal sparse structure of a 3 × 3 square PD ultrasonic array sensor is deduced. It is found that, under different sparseness and sparse structure, the main beam width of the directivity function shows a small variation, while the sidelobe amplitude shows a bigger variation. For a specific sparseness, the acoustic performance under the optimal sparse structure is close to that using a full array. Finally, some simulations based on the above method show that, for certain sparseness, the sensor with the optimal sparse structure exhibits superior positioning accuracy compared to that with a stochastic one. The sensor array structure may be chosen according to the actual requirements for an actual engineering application.

  1. Preliminary vibration, acoustic, and shock design and test criteria for components on the SRB, ET, and SSME

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Specifications for vibration, acoustic and shock design for components and subassemblies on the External Tank (ET), Solid Rocket Booster (SRB), and Space Shuttle Main Engine (SSME). Included are vibration, acoustic, shock, transportation, handling, and acceptance test requirements and procedures. The space shuttle ET, SRB, and SSME have been divided into zones and subzones. Zones are designated primarily to assist in determining the applicable specifications. A subzone (General Specification) is available for use when the location of the component is known but component design and weight are not well defined. When the location, weight, and mounting configuration of the component are known, specifications for appropriate subzone weight ranges are available. Criteria for some specific components are also presented.

  2. The design of Helmholtz resonator based acoustic lenses by using the symmetric Multi-Level Wave Based Method and genetic algorithms

    NASA Astrophysics Data System (ADS)

    Atak, Onur; Huybrechs, Daan; Pluymers, Bert; Desmet, Wim

    2014-07-01

    Sonic crystals can be used as acoustic lenses in certain frequencies and the design of such systems by creating vacancies and using genetic algorithms has been proven to be an effective method. So far, rigid cylinders have been used to create such acoustic lens designs. On the other hand, it has been proven that Helmholtz resonators can be used to construct acoustic lenses with higher refraction index as compared to rigid cylinders, especially in low frequencies by utilizing their local resonances. In this paper, these two concepts are combined to design acoustic lenses that are based on Helmholtz resonators. The Multi-Level Wave Based Method is used as the prediction method. The benefits of the method in the context of design procedure are demonstrated. In addition, symmetric boundary conditions are derived for more efficient calculations. The acoustic lens designs that use Helmholtz resonators are compared with the acoustic lens designs that use rigid cylinders. It is shown that using Helmholtz resonator based sonic crystals leads to better acoustic lens designs, especially at the low frequencies where the local resonances are pronounced.

  3. Acoustic neuroma

    MedlinePlus

    Vestibular schwannoma; Tumor - acoustic; Cerebellopontine angle tumor; Angle tumor; Hearing loss - acoustic; Tinnitus - acoustic ... Acoustic neuromas have been linked with the genetic disorder neurofibromatosis type 2 (NF2). Acoustic neuromas are uncommon.

  4. Award 1 Title: Acoustic Communications 2011 Experiment: Deployment Support and Post Experiment Data Handling and Analysis. Award 2 Title: Exploiting Structured Dependencies in the Design of Adaptive Algorithms for Underwater Communication Award. 3 Title: Coupled Research in Ocean Acoustics and Signal Processing for the Next Generation of Underwater Acoustic Communication Systems

    DTIC Science & Technology

    2015-09-30

    Exploiting Structured Dependencies in the Design of Adaptive Algorithms for Underwater Communication Award #3 Title Coupled Research in Ocean Acoustics...depend on the physical oceanography and pushing the state of the art in our understanding of adaptive signal processing algorithms relevant to...deployable VHF acoustic data transmission and acquisition system. 3. Develop signal models and processing algorithms that reduce to the extent

  5. Mass sensitivity analysis and designing of surface acoustic wave resonators for chemical sensors

    NASA Astrophysics Data System (ADS)

    Kshetrimayum, Roshan; Yadava, R. D. S.; Tandon, R. P.

    2009-05-01

    The sensitivity of surface acoustic wave (SAW) chemical sensors depends on several factors such as the frequency and phase point of SAW device operation, sensitivity of the SAW velocity to surface mass loading, sensitivity of the SAW oscillator resonance to the loop phase shift, film thickness and oscillator electronics. This paper analyzes the influence of the phase point of operation in SAW oscillator sensors based on two-port resonator devices. It is found that the mass sensitivity will be enhanced if the SAW device has a nonlinear dependence on the frequency (delay ~ frequency-1). This requires the device to generate and operate in a ωτg(ω) = const region in the device passband, where ω denotes the angular frequency of oscillation and τg(ω) denotes the phase slope of the SAW resonator device. A SAW coupled resonator filter (CRF) that take advantage of mode coupling is considered in realizing such a device to help in shaping the phase transfer characteristics of a high mass sensitivity sensor. The device design and simulation results are presented within the coupling-of-modes formalism.

  6. SU-E-T-208: Incidence Cancer Risk From the Radiation Treatment for Acoustic Neuroma Patient

    SciTech Connect

    Kim, D; Chung, W; Shin, D; Yoon, M

    2014-06-01

    Purpose: The present study aimed to compare the incidence risk of a secondary cancer from therapeutic doses in patients receiving intensitymodulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic radiosurgery (SRS). Methods: Four acoustic neuroma patients were treated with IMRT, VMAT, or SRS. Their incidnece excess relative risk (ERR), excess absolute risk (EAR), and lifetime attributable risk (LAR) were estimated using the corresponding therapeutic doses measured at various organs by radio-photoluminescence glass dosimeters (RPLGD) placed inside a humanoid phantom. Results: When a prescription dose was delivered in the planning target volume of the 4 patients, the average organ equivalent doses (OED) at the thyroid, lung, normal liver, colon, bladder, prostate (or ovary), and rectum were measured. The OED decreased as the distance from the primary beam increased. The thyroid received the highest OED compared to other organs. A LAR were estimated that more than 0.03% of AN patients would get radiation-induced cancer. Conclusion: The tyroid was highest radiation-induced cancer risk after radiation treatment for AN. We found that LAR can be increased by the transmitted dose from the primary beam. No modality-specific difference in radiation-induced cancer risk was observed in our study.

  7. Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface

    NASA Astrophysics Data System (ADS)

    Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A.

    2014-11-01

    Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell’s law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications.

  8. Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface.

    PubMed

    Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A

    2014-11-24

    Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell's law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications.

  9. Acoustic evaluation and adjustment of an open-plan office through architectural design and noise control.

    PubMed

    Passero, Carolina Reich Marcon; Zannin, Paulo Henrique Trombetta

    2012-11-01

    Arranging office space into a single open room offers advantages in terms of easy exchange of information and interaction among coworkers, but reduces privacy and acoustic comfort. Thus, the purpose of this work was to evaluate the acoustic quality of a real open-plan office and to propose changes in the room to improve the acoustic conditioning of this office. The computational model of the office under study was calibrated based on RT and STI measurements. Predictions were made of the RT and STI, which generated the radius of distraction r(D), and the rate of spatial decay of sound pressure levels per distance doubling DL(2) in the real conditions of the office and after modifications of the room. The insertion of dividers between work stations and an increase in the ceiling's sound absorption improved the acoustic conditions in the office under study.

  10. Vibration, acoustic, and shock design and test criteria for components on the Solid Rocket Boosters (SRB), Lightweight External Tank (LWT), and Space Shuttle Main Engines (SSME)

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The vibration, acoustics, and shock design and test criteria for components and subassemblies on the space shuttle solid rocket booster (SRB), lightweight tank (LWT), and main engines (SSME) are presented. Specifications for transportation, handling, and acceptance testing are also provided.

  11. A rail system for circular synthetic aperture sonar imaging and acoustic target strength measurements: design/operation/preliminary results.

    PubMed

    Kennedy, J L; Marston, T M; Lee, K; Lopes, J L; Lim, R

    2014-01-01

    A 22 m diameter circular rail, outfitted with a mobile sonar tower trolley, was designed, fabricated, instrumented with underwater acoustic transducers, and assembled on a 1.5 m thick sand layer at the bottom of a large freshwater pool to carry out sonar design and target scattering response studies. The mobile sonar tower translates along the rail via a drive motor controlled by customized LabVIEW software. The rail system is modular and assembly consists of separately deploying eight circular arc sections, measuring a nominal center radius of 11 m and 8.64 m arc length each, and having divers connect them together in the underwater environment. The system enables full scale measurements on targets of interest with 0.1° angular resolution over a complete 360° aperture, without disrupting target setup, and affording a level of control over target environment conditions and noise sources unachievable in standard field measurements. In recent use, the mobile cart carrying an instrumented sonar tower was translated along the rail in 720 equal position increments and acoustic backscatter data were acquired at each position. In addition, this system can accommodate both broadband monostatic and bistatic scattering measurements on targets of interest, allowing capture of target signature phenomena under diverse configurations to address current scientific and technical issues encountered in mine countermeasure and unexploded ordnance applications. In the work discussed here, the circular rail apparatus is used for acoustic backscatter testing, but this system also has the capacity to facilitate the acquisition of magnetic and optical sensor data from targets of interest. A brief description of the system design and operation will be presented along with preliminary processed results for data acquired from acoustic measurements conducted at the Naval Surface Warfare Center, Panama City Division Test Pond Facility. [Work Supported by the U.S. Office of Naval Research and

  12. Design and implementation of low complexity wake-up receiver for underwater acoustic sensor networks

    NASA Astrophysics Data System (ADS)

    Yue, Ming

    This thesis designs a low-complexity dual Pseudorandom Noise (PN) scheme for identity (ID) detection and coarse frame synchronization. The two PN sequences for a node are identical and are separated by a specified length of gap which serves as the ID of different sensor nodes. The dual PN sequences are short in length but are capable of combating severe underwater acoustic (UWA) multipath fading channels that exhibit time varying impulse responses up to 100 taps. The receiver ID detection is implemented on a microcontroller MSP430F5529 by calculating the correlation between the two segments of the PN sequence with the specified separation gap. When the gap length is matched, the correlator outputs a peak which triggers the wake-up enable. The time index of the correlator peak is used as the coarse synchronization of the data frame. The correlator is implemented by an iterative algorithm that uses only one multiplication and two additions for each sample input regardless of the length of the PN sequence, thus achieving low computational complexity. The real-time processing requirement is also met via direct memory access (DMA) and two circular buffers to accelerate data transfer between the peripherals and the memory. The proposed dual PN detection scheme has been successfully tested by simulated fading channels and real-world measured channels. The results show that, in long multipath channels with more than 60 taps, the proposed scheme achieves high detection rate and low false alarm rate using maximal-length sequences as short as 31 bits to 127 bits, therefore it is suitable as a low-power wake-up receiver. The future research will integrate the wake-up receiver with Digital Signal Processors (DSP) for payload detection.

  13. An ultra-low power and flexible acoustic modem design to develop energy-efficient underwater sensor networks.

    PubMed

    Sánchez, Antonio; Blanc, Sara; Yuste, Pedro; Perles, Angel; Serrano, Juan José

    2012-01-01

    This paper is focused on the description of the physical layer of a new acoustic modem called ITACA. The modem architecture includes as a major novelty an ultra-low power asynchronous wake-up system implementation for underwater acoustic transmission that is based on a low-cost off-the-shelf RFID peripheral integrated circuit. This feature enables a reduced power dissipation of 10 μW in stand-by mode and registers very low power values during reception and transmission. The modem also incorporates clear channel assessment (CCA) to support CSMA-based medium access control (MAC) layer protocols. The design is part of a compact platform for a long-life short/medium range underwater wireless sensor network.

  14. An Ultra-Low Power and Flexible Acoustic Modem Design to Develop Energy-Efficient Underwater Sensor Networks

    PubMed Central

    Sánchez, Antonio; Blanc, Sara; Yuste, Pedro; Perles, Angel; Serrano, Juan José

    2012-01-01

    This paper is focused on the description of the physical layer of a new acoustic modem called ITACA. The modem architecture includes as a major novelty an ultra-low power asynchronous wake-up system implementation for underwater acoustic transmission that is based on a low-cost off-the-shelf RFID peripheral integrated circuit. This feature enables a reduced power dissipation of 10 μW in stand-by mode and registers very low power values during reception and transmission. The modem also incorporates clear channel assessment (CCA) to support CSMA-based medium access control (MAC) layer protocols. The design is part of a compact platform for a long-life short/medium range underwater wireless sensor network. PMID:22969324

  15. Noise reduction as affected by the extent and distribution of acoustic treatment in a turbofan engine inlet

    NASA Technical Reports Server (NTRS)

    Minner, G. L.; Homyak, L.

    1976-01-01

    An inlet noise suppressor for a TF-34 engine designed to have three acoustically treated rings was tested with several different ring arrangements. The configurations included: all three rings; two outer rings; single outer ring; single intermediate ring, and finally no rings. It was expected that as rings were removed, the acoustic performance would be degraded considerably. While a degradation occurred, it was not as large as predictions indicated. In fact, the prediction showed good agreement with the data only for the full-ring inlet configuration. The under-predictions which occurred with ring removal were believed a result of ignoring the presence of spinning modes which are known to damp more rapidly in cylindrical ducts than would be predicted by least attenuated mode or plane wave analysis.

  16. Noise reduction as affected by the extent and distribution of acoustic treatment in a turbofan engine inlet

    NASA Technical Reports Server (NTRS)

    Minner, G. L.; Homyak, L.

    1976-01-01

    An inlet noise suppressor for a TF-34 engine designed to have three acoustically treated rings was tested with several different ring arrangements. The configurations included: all three rings; two outer rings; single outer ring; single intermediate ring, and finally no rings. It was expected that as rings were removed, the acoustic performance would be degraded considerably. While a degradation occurred, it was not as large as predictions indicated. The prediction showed good agreement with the data only for the full-ring inlet configuration. The underpredictions which occurred with ring removal were believed a result of ignoring the presence of spinning modes which are known to damp more rapidly in cylindrical ducts than would be predicted by least attenuated mode or plane wave analysis.

  17. Magnetic nanoparticles-based acoustical detection and hyperthermic treatment of cancer, in vitro and in vivo studies

    NASA Astrophysics Data System (ADS)

    Shoval, Asaf; Tepper, Michal; Tikochkiy, Jenny; Gur, Leah Ben; Markovich, Gil; Keisari, Yona; Gannot, Israel

    2016-07-01

    This paper describes a minimally invasive method for detection and growth inhibition of tumors that utilizes the unique properties of super paramagnetic nanoparticles. To demonstrate the feasibility of this method, dimercaptosuccinic acid-coated magnetite nanoparticles were successfully fabricated and used. Those nanoparticles were simultaneously used for magnetoacoustic detection of tumors and for specific hyperthermia treatment in C57BL/J mice injected with Lewis lung carcinoma cells. The in vivo acoustic signal attributed to the nanoparticles was 4.4 dB, while the single session hyperthermia treatment caused a reduction of 50% in tumor growing rate. In addition, a thermography-based method was applied to monitor the efficacy of the hyperthermia treatment. The presented method has the potential to revolutionize current cancer treatment by enabling diagnosis and treatment under real-time feedback in one session.

  18. Design and construction of a reverberation chamber for high-intensity acoustic testing.

    NASA Technical Reports Server (NTRS)

    Slusser, R. A.

    1973-01-01

    A high-intensity acoustic test facility was constructed at the Jet Propulsion Laboratory (JPL) to support the Mariner Mars 1971 project. For ease of construction, the reverberation chamber itself is rectangular, which resulted in very little sacrifice in acoustic performance. Levels as high as 156 dB can be achieved with the chamber empty and test levels of 150 dB have been used with a Mariner Mars spacecraft model (full size) in the chamber. Levels as high as this must be generated using electropneumatic transducers, which modulate gaseous nitrogen to this facility.

  19. Optimal design of distributed wastewater treatment networks

    SciTech Connect

    Galan, B.; Grossmann, I.E.

    1998-10-01

    This paper deals with the optimum design of a distributed wastewater network where multicomponent streams are considered that are to be processed by units for reducing the concentration of several contaminants. The proposed model gives rise to a nonconvex nonlinear problem which often exhibits local minima and causes convergence difficulties. A search procedure is proposed in this paper that is based on the successive solution of a relaxed linear model and the original nonconvex nonlinear problem. Several examples are presented to illustrate that the proposed method often yields global or near global optimum solutions. The model is also extended for selecting different treatment technologies and for handling membrane separation modules.

  20. Design of broadband time-domain impedance boundary conditions using the oscillatory-diffusive representation of acoustical models.

    PubMed

    Monteghetti, Florian; Matignon, Denis; Piot, Estelle; Pascal, Lucas

    2016-09-01

    A methodology to design broadband time-domain impedance boundary conditions (TDIBCs) from the analysis of acoustical models is presented. The derived TDIBCs are recast exclusively as first-order differential equations, well-suited for high-order numerical simulations. Broadband approximations are yielded from an elementary linear least squares optimization that is, for most models, independent of the absorbing material geometry. This methodology relies on a mathematical technique referred to as the oscillatory-diffusive (or poles and cuts) representation, and is applied to a wide range of acoustical models, drawn from duct acoustics and outdoor sound propagation, which covers perforates, semi-infinite ground layers, as well as cavities filled with a porous medium. It is shown that each of these impedance models leads to a different TDIBC. Comparison with existing numerical models, such as multi-pole or extended Helmholtz resonator, provides insights into their suitability. Additionally, the broadly-applicable fractional polynomial impedance models are analyzed using fractional calculus.

  1. Acoustic Liner for Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    Huff, Dennis L.; Sutliff, Daniel L.; Jones, Michael G.; Hebsur, Mohan G.

    2010-01-01

    The purpose of this innovation is to reduce aircraft noise in the communities surrounding airports by significantly attenuating the noise generated by the turbomachinery, and enhancing safety by providing a containment barrier for a blade failure. Acoustic liners are used in today's turbofan engines to reduce noise. The amount of noise reduction from an acoustic liner is a function of the treatment area, the liner design, and the material properties, and limited by the constraints of the nacelle or casement design. It is desirable to increase the effective area of the acoustic treatment to increase noise suppression. Modern turbofan engines use wide-chord rotor blades, which means there is considerable treatment area available over the rotor tip. Turbofan engines require containment over the rotors for protection from blade failure. Traditional methods use a material wrap such as Kevlar integrated with rub strips and sometimes metal layers (sandwiches). It is possible to substitute the soft rub-strip material with an open-cell metallic foam that provides noise-reduction benefits and a sacrificial material in the first layer of the containment system. An open-cell foam was evaluated that behaves like a bulk acoustic liner, serves as a tip rub strip, and can be integrated with a rotor containment system. Foams can be integrated with the fan-containment system to provide sufficient safety margins and increased noise attenuation. The major innovation is the integration of the foam with the containment.

  2. Design and Evaluation of a Scalable and Reconfigurable Multi-Platform System for Acoustic Imaging

    PubMed Central

    Izquierdo, Alberto; Villacorta, Juan José; del Val Puente, Lara; Suárez, Luis

    2016-01-01

    This paper proposes a scalable and multi-platform framework for signal acquisition and processing, which allows for the generation of acoustic images using planar arrays of MEMS (Micro-Electro-Mechanical Systems) microphones with low development and deployment costs. Acoustic characterization of MEMS sensors was performed, and the beam pattern of a module, based on an 8 × 8 planar array and of several clusters of modules, was obtained. A flexible framework, formed by an FPGA, an embedded processor, a computer desktop, and a graphic processing unit, was defined. The processing times of the algorithms used to obtain the acoustic images, including signal processing and wideband beamforming via FFT, were evaluated in each subsystem of the framework. Based on this analysis, three frameworks are proposed, defined by the specific subsystems used and the algorithms shared. Finally, a set of acoustic images obtained from sound reflected from a person are presented as a case study in the field of biometric identification. These results reveal the feasibility of the proposed system. PMID:27727174

  3. New design of the pulsed electro-acoustic upper electrode for space charge measurements during electronic irradiation.

    PubMed

    Riffaud, J; Griseri, V; Berquez, L

    2016-07-01

    The behaviour of space charges injected in irradiated dielectrics has been studied for many years for space industry applications. In our case, the pulsed electro-acoustic method is chosen in order to determine the spatial distribution of injected electrons. The feasibility of a ring-shaped electrode which will allow the measurements during irradiation is presented. In this paper, a computer simulation is made in order to determine the parameters to design the electrode and find its position above the sample. The obtained experimental results on polyethylene naphthalate samples realized during electronic irradiation and through relaxation under vacuum will be presented and discussed.

  4. New design of the pulsed electro-acoustic upper electrode for space charge measurements during electronic irradiation

    NASA Astrophysics Data System (ADS)

    Riffaud, J.; Griseri, V.; Berquez, L.

    2016-07-01

    The behaviour of space charges injected in irradiated dielectrics has been studied for many years for space industry applications. In our case, the pulsed electro-acoustic method is chosen in order to determine the spatial distribution of injected electrons. The feasibility of a ring-shaped electrode which will allow the measurements during irradiation is presented. In this paper, a computer simulation is made in order to determine the parameters to design the electrode and find its position above the sample. The obtained experimental results on polyethylene naphthalate samples realized during electronic irradiation and through relaxation under vacuum will be presented and discussed.

  5. Finite element modeling of acoustic wave propagation and energy deposition in bone during extracorporeal shock wave treatment

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofeng; Matula, Thomas J.; Ma, Yong; Liu, Zheng; Tu, Juan; Guo, Xiasheng; Zhang, Dong

    2013-06-01

    It is well known that extracorporeal shock wave treatment is capable of providing a non-surgical and relatively pain free alternative treatment modality for patients suffering from musculoskeletal disorders but do not respond well to conservative treatments. The major objective of current work is to investigate how the shock wave (SW) field would change if a bony structure exists in the path of the acoustic wave. Here, a model of finite element method (FEM) was developed based on linear elasticity and acoustic propagation equations to examine SW propagation and deflection near a mimic musculoskeletal bone. High-speed photography experiments were performed to record cavitation bubbles generated in SW field with the presence of mimic bone. By comparing experimental and simulated results, the effectiveness of FEM model could be verified and strain energy distributions in the bone were also predicted according to numerical simulations. The results show that (1) the SW field will be deflected with the presence of bony structure and varying deflection angles can be observed as the bone shifted up in the z-direction relative to SW geometric focus (F2 focus); (2) SW deflection angels predicted by the FEM model agree well with experimental results obtained from high-speed photographs; and (3) temporal evolutions of strain energy distribution in the bone can also be evaluated based on FEM model, with varied vertical distance between F2 focus and intended target point on the bone surface. The present studies indicate that, by combining MRI/CT scans and FEM modeling work, it is possible to better understand SW propagation characteristics and energy deposition in musculoskeletal structure during extracorporeal shock wave treatment, which is important for standardizing the treatment dosage, optimizing treatment protocols, and even providing patient-specific treatment guidance in clinic.

  6. Structural acoustic control of plates with variable boundary conditions: design methodology.

    PubMed

    Sprofera, Joseph D; Cabell, Randolph H; Gibbs, Gary P; Clark, Robert L

    2007-07-01

    A method for optimizing a structural acoustic control system subject to variations in plate boundary conditions is provided. The assumed modes method is used to build a plate model with varying levels of rotational boundary stiffness to simulate the dynamics of a plate with uncertain edge conditions. A transducer placement scoring process, involving Hankel singular values, is combined with a genetic optimization routine to find spatial locations robust to boundary condition variation. Predicted frequency response characteristics are examined, and theoretically optimized results are discussed in relation to the range of boundary conditions investigated. Modeled results indicate that it is possible to minimize the impact of uncertain boundary conditions in active structural acoustic control by optimizing the placement of transducers with respect to those uncertainties.

  7. Designing new treatments for depression and anxiety.

    PubMed

    Chen, Zhengming; Yang, Ji; Tobak, Anne

    2008-03-01

    Depression and anxiety are disabling disorders that affect many individuals. Drugs that interfere with the reuptake and/or metabolism of biogenic amines have been used to treat depression for more than four decades. An important development in the treatment of depression has been the emergence of triple reuptake inhibitors (SNDRIs), which inhibit the reuptake of serotonin, norepinephrine and dopamine. Preclinical and clinical research indicates that drugs inhibiting the reuptake of all of these neurotransmitters can produce a more rapid onset of action and greater efficacy than traditional antidepressants. Allosteric modulation of GABAA receptors can produce anxiolytic, sedative/hypnotic and anesthetic effects, presumably from enhancing the inhibitory neurotransmission of GABAA through a facilitation of receptor function. Benzodiazepines have been used with great success as anxiolytics, but the use of these drugs is limited because of their addictive potential and sedative side effects. This feature review discusses the design and synthesis of antidepressants based on the monoamine hypothesis of depression, and presents the current status of research on GABAA receptor modulators as a potential treatment for anxiety disorders.

  8. Laboratory tests on an aircraft fuselage to determine the insertion loss of various acoustic add-on treatments

    NASA Technical Reports Server (NTRS)

    Heitman, K. E.; Mixson, J. S.

    1984-01-01

    This paper describes a laboratory study of add-on acoustic treatments for a propeller-driven light aircraft fuselage. The treatments included: no treatment (i.e., baseline fuselage); a production-type double-wall interior; and various amounts of high density fiberglass added to the baseline fuselage. The sound source was a pneumatic-driver with attached exponential horn, supplied with a broadband signal. Data were acquired at the approximate head positions of the six passenger seats. The results were analyzed on space-averaged narrowband, one-third octave band and overall insertion loss basis. In addition, insertion loss results for the different configurations at specific frequencies representing propeller tone spectra are presented. The propeller tone data includes not only the space-averaged insertion loss, but also the variation of insertion loss at these particular frequencies across the six microphone positions.

  9. Lobed Mixer Design for Noise Suppression: Plume, Aerodynamic and Acoustic Data. Volume 2

    NASA Technical Reports Server (NTRS)

    Mengle, Vinod G.; Baker, V. David; Dalton, William N.; Bridges, James (Technical Monitor)

    2002-01-01

    A comprehensive database for the acoustic and aerodynamic characteristics of several model-scale lobe mixers of bypass ratio 5 to 6 has been created for mixed jet speeds up to 1080 ft per s at typical take-off (TO) conditions of small-to-medium turbofan engines. The flight effect was simulated for Mach numbers up to 0.3. The static thrust performance and plume data were also obtained at typical TO and cruise conditions. The tests were done at NASA Lewis anechoic dome and ASE's FluiDyne Laboratories. The effect of several lobe mixer and nozzle parameters, such as, lobe scalloping, lobe count, lobe penetration and nozzle length was examined in terms of flyover noise at constant altitude and also noise in the reference frame of the nozzle. This volume is divided into three parts: in the first two parts, we collate the plume survey data in graphical form (line, contour and surface plots) and analyze it; in part 3, we tabulate the aerodynamic data for the acoustics tests and the acoustic data in one-third octave band levels.

  10. Design and characterization of fibrin-based acoustically responsive scaffolds for tissue engineering applications

    PubMed Central

    Moncion, Alexander; Arlotta, Keith J.; Kripfgans, Oliver D.; Fowlkes, J. Brian; Carson, Paul L.; Putnam, Andrew J.; Franceschi, Renny T.; Fabiilli, Mario L.

    2015-01-01

    Hydrogel scaffolds are used in tissue engineering as a delivery vehicle for regenerative growth factors (GFs). Spatiotemporal patterns of GF signaling are critical for tissue regeneration, yet most scaffolds afford limited control of GF release, especially after implantation. We previously demonstrated that acoustic droplet vaporization (ADV) can control GF release from a fibrin scaffold doped with a perfluorocarbon emulsion. This study investigates properties of the acoustically responsive scaffold (ARS) critical for further translation. At 2.5 MHz, ADV and inertial cavitation thresholds ranged from 1.5 – 3.0 MPa and 2.0 – 7.0 MPa peak rarefactional pressure, respectively, for ARSs of varying compositions. Viability of C3H10T1/2 cells, encapsulated in the ARS, did not decrease significantly for pressures below 4 MPa. ARSs with perfluorohexane emulsions displayed higher stability versus perfluoropentane emulsions, while surrogate payload release was minimal without ultrasound. These results enable the selection of ARS compositions and acoustic parameters needed for optimized spatiotemporal control. PMID:26526782

  11. Acoustics of early music spaces from the 11th to 18th century: Rediscovery of the acoustical excellence of medium-sized rooms and new perspectives for modern concert hall design

    NASA Astrophysics Data System (ADS)

    Bassuet, Alban

    2004-05-01

    The acoustical characteristics of 50 rooms that played a prominent role in the history of music between the 11th and 18th centuries were studied. The rooms include basilicas, oratorios, organ churches, and the great halls and courts of the European palaces. The research provides an understanding of the acoustical features that suit the early music repertoire, and how these rooms achieved an enhanced emotional engagement through their unique acoustical characteristics. This paper provides a summary of the acoustic measurements, which include binaural and B-format recordings in each of the rooms, and presents a unique new approach to understanding their subjective characteristics through detailed analysis and auralization of their 3-D impulse response. The study shows that the timing and direction of reflections in three dimensions is critically important to defining the subjective characteristic of a room. The results emphasize the importance of developing techniques to understand the 3-D impulse response and using auralization techniques for interpreting results and making subjective judgments. The enhanced musical experience that is achieved in these early rooms offers an invitation to rethink modern acoustics and to develop a new design approach that focuses more strongly on the subjective response and emotional engagement of the music.

  12. Subjective, laryngoscopic, and acoustic measurements of laryngeal reflux before and after treatment with omeprazole.

    PubMed

    Shaw, G Y; Searl, J P; Young, J L; Miner, P B

    1996-12-01

    Laryngeal manifestation of gastroesophageal reflux is felt to be prevalent in our society. In general, diagnosis has been based primarily on symptoms. Historically, additional testing included laryngoscopy, barium swallow, manometry, and more recently, single- and double-probe pH monitoring. We evaluated 68 patients who were symptomatically suggestive of having reflux laryngitis. We administered surveys grading their symptoms. All patients underwent standardized videolaryngostroboscopic evaluation and computerized acoustic analysis. Patients then underwent a uniform therapy of dietary restrictions and omeprazole, a hydrogen ion inhibitor, for 12 weeks. Patients were then retested. This regimen demonstrated an 85% success of relieving symptoms. Utilizing the new laryngoscopic grading system, improvement was found to be statistically significant in improvement of all findings except granulomas. In patients with the pretherapy complaint of hoarseness, acoustic measures of jitter, shimmer, habitual frequency, and frequency range all showed significant improvement. The authors conclude that in patients with symptomatic reflux laryngitis, standardized videolaryngoscopy and, if hoarse, acoustic analysis are useful exam techniques to aide diagnosis and monitor therapy. Anti-reflux therapy with omeprazole is effective and improvement can be objectively demonstrated with the techniques described.

  13. Prediction and Measurement of the Vibration and Acoustic Radiation of Panels Subjected to Acoustic Loading

    NASA Technical Reports Server (NTRS)

    Turner, Travis L.; Rizzi, Stephen A.

    1995-01-01

    Interior noise and sonic fatigue are important issues in the development and design of advanced subsonic and supersonic aircraft. Conventional aircraft typically employ passive treatments, such as constrained layer damping and acoustic absorption materials, to reduce the structural response and resulting acoustic levels in the aircraft interior. These techniques require significant addition of mass and only attenuate relatively high frequency noise transmitted through the fuselage. Although structural acoustic coupling is in general very important in the study of aircraft fuselage interior noise, analysis of noise transmission through a panel supported in an infinite rigid baffle (separating two semi-infinite acoustic domains) can be useful in evaluating the effects of active/adaptive materials, complex loading, etc. Recent work has been aimed at developing adaptive and/or active methods of controlling the structural acoustic response of panels to reduce the transmitted noise1. A finite element formulation was recently developed to study the dynamic response of shape memory alloy (SMA) hybrid composite panels (conventional composite panel with embedded SMA fibers) subject to combined acoustic and thermal loads2. Further analysis has been performed to predict the far-field acoustic radiation using the finite element dynamic panel response prediction3. The purpose of the present work is to validate the panel vibration and acoustic radiation prediction methods with baseline experimental results obtained from an isotropic panel, without the effect of SMA.

  14. Acoustic and auditory phonetics: the adaptive design of speech sound systems.

    PubMed

    Diehl, Randy L

    2008-03-12

    Speech perception is remarkably robust. This paper examines how acoustic and auditory properties of vowels and consonants help to ensure intelligibility. First, the source-filter theory of speech production is briefly described, and the relationship between vocal-tract properties and formant patterns is demonstrated for some commonly occurring vowels. Next, two accounts of the structure of preferred sound inventories, quantal theory and dispersion theory, are described and some of their limitations are noted. Finally, it is suggested that certain aspects of quantal and dispersion theories can be unified in a principled way so as to achieve reasonable predictive accuracy.

  15. Computer program design for land treatment systems

    SciTech Connect

    White, R.K. ); Jantrania, A.

    1989-10-01

    Municipal Sludge Land Application expert System (MuSLAXS)is as expert system developed for site assessment and design analysis of municipal sludge application on agricultural land. The system has knowledge on the technical and regulatory aspects of sludge land application and understanding of soil-plant systems for South Carolina. It can be effectively used outside South Carolina with modifications to incorporate specific regulations on land treatment and soil and crop database. A database supports this expert system and provides appropriate default values for sludge and soil characteristics, and fertilizer recommendations for crops commonly grown in South Carolina. Information on the sludge characteristics is gathered from the user, if it is available, or it is retrieved from the sludge database. Based on the recommendations by the EPA and the expert, a list of 22 constituents, for which the sludge should be analyzed is developed. This list includes: total solids, volatile solids, total nitrogen (TNK), ammonia-nitrogen, organic-nitrogen, phosphorus, potassium, sulfur, cadmium, copper, lead, nickel, zinc, PCBs, calcium, magnesium, chromium, boron, arsenic, aluminum, cobalt, and molybdenum.

  16. Acoustic Neuroma

    MedlinePlus

    ... search IRSA's site Unique Hits since January 2003 Acoustic Neuroma Click Here for Acoustic Neuroma Practice Guideline ... to microsurgery. One doctor's story of having an acoustic neuroma In August 1991, Dr. Thomas F. Morgan ...

  17. Initial evaluation of acoustic reflectors for the preservation of sensitive abdominal skin areas during MRgFUS treatment.

    PubMed

    Gorny, Krzysztof R; Chen, Shigao; Hangiandreou, Nicholas J; Hesley, Gina K; Woodrum, David A; Brown, Douglas L; Felmlee, Joel P

    2009-04-21

    During MR-guided focused ultrasound (MRgFUS) treatments of uterine fibroids using ExAblate(R)2000 (InSightec, Haifa, Israel), individual tissue ablations are performed extracorporeally through the patient's abdomen using an annular array FUS transducer embedded within the MR table. Ultrasound intensities in the near field are below therapeutic levels and, under normal conditions, heating of the patient skin is minimal. However, increased absorption of ultrasound energy within sensitive skin areas or areas with differing acoustic properties, such as scars, may lead to skin burns and therefore these areas must be kept outside the near field of the FUS beam. Depending on their location and size the sensitive areas may either obstruct parts of the fibroid from being treated or prevent the entire MRgFUS treatment altogether. The purpose of this work is to evaluate acoustic reflector materials that can be applied to protect skin and the underlying sensitive areas. Reflection coefficients of cork (0.88) and foam (0.91) based materials were evaluated with a hydrophone. An ExAblate 2000 MRgFUS system was used to simulate clinical treatment with discs of reflector materials placed in a near field underneath a gel phantom. MR thermometry was used to monitor temperature elevations as well as the integrity of the focal spot. The phantom measurements showed acoustic shadow zones behind the reflectors with zone depths changing between 7 and 27 mm, for reflector disc diameters increasing from 10 to 30 mm (40 mm diameter discs completely blocked the FUS beam at the depth evaluated). The effects on thermal lesions due to the presence of the reflectors in the FUS beam were found to diminish with decreasing disc diameter and increasing sonication depth. For a 20 mm diameter disc and beyond 50 mm sonication depth, thermal lesions were minimally affected by the presence of the disc. No heating was observed on the skin side of the foam reflectors, as confirmed by measurements performed

  18. An acoustic bending waveguide designed by anisotropic density-near-zero metamaterial

    NASA Astrophysics Data System (ADS)

    Wang, Yang-Yang; Ding, Er-Liang; Liu, Xiao-Zhou; Gong, Xiu-Fen

    2016-12-01

    Anisotropic metamaterial with only one component of the mass density tensor near zero (ADNZ) is proposed to control the sound wave propagation. We find that such an anisotropic metamaterial can be used to realize perfect bending waveguides. According to a coordinate transformation, the surface waves on the input and output interfaces of the ADNZ metamaterial induces the sound energy flow to be redistributed and match smoothly with the propagating modes inside the metamaterial waveguide. According to the theory of bending waveguide, we realize the “T”-type sound shunting and convergence, as well as acoustic channel selection by embedding small-sized defects. Numerical calculations are performed to confirm the above effects. Project supported by the National Basic Research Program of China (Grant No. 2012CB921504), the National Natural Science Foundation of China (Grant No. 11474160), the Fundamental Research Funds for the Central Universities, China (Grant No. 020414380001), the State Key Laboratory of Acoustics, Chinese Academy of Sciences (Grant No. SKLA201609), and the Priority Academic Program Development of Jiangsu Higher Education Institution, China.

  19. Design of acoustic wave biochemical sensors using micro-electro-mechanical systems

    NASA Astrophysics Data System (ADS)

    Valentine, Jane E.; Przybycien, Todd M.; Hauan, Steinar

    2007-03-01

    Acoustic wave biochemical sensors work by detecting the frequency shifts resulting from the binding of target molecules to a functionalized resonator. Resonator types currently in use or under development include macroscopic quartz crystal microbalances (QCMs) as well as a number of different integrated Micro-electro-mechanical Systems (MEMS) structures. Due to an increased resonator surface area to mass ratio, we believe that membrane-based MEMS systems are particularly promising with regard to sensitivity. Prototypes have been developed [S. Hauan et al., U.S. Patent Application (filed 6 Nov. 2003)] and preliminary calculations [M. J. Bartkovsky et al., paper 385e presented at the AIChE Annual Meeting, Nov. 2003; J. E. Valentine et al., paper 197h presented at the AICHE Annual Meeting, Nov. 2003] indicate significant improvements over other methods, both macroscopic and MEMS based. In this article we describe our work on a MEMS-based acoustic wave biochemical sensor using a membrane resonator. We demonstrate the effects of spatial distributions of mass on the membrane on sensitivity and show how to use this spatial sensitivity to detect multiple targets simultaneously. To do so we derive a function approximating the membrane response surface to spatial mass loadings under the applicable range of conditions. We verify the agreement using finite element methods, and present our initial sensitivity calculations demonstrating the advantages of variable mass loadings.

  20. Finite Difference Time Marching in the Frequency Domain: A Parabolic Formulation for Aircraft Acoustic Nacelle Design

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.; Kreider, Kevin L.

    1996-01-01

    An explicit finite difference iteration scheme is developed to study harmonic sound propagation in aircraft engine nacelles. To reduce storage requirements for large 3D problems, the time dependent potential form of the acoustic wave equation is used. To insure that the finite difference scheme is both explicit and stable, time is introduced into the Fourier transformed (steady-state) acoustic potential field as a parameter. Under a suitable transformation, the time dependent governing equation in frequency space is simplified to yield a parabolic partial differential equation, which is then marched through time to attain the steady-state solution. The input to the system is the amplitude of an incident harmonic sound source entering a quiescent duct at the input boundary, with standard impedance boundary conditions on the duct walls and duct exit. The introduction of the time parameter eliminates the large matrix storage requirements normally associated with frequency domain solutions, and time marching attains the steady-state quickly enough to make the method favorable when compared to frequency domain methods. For validation, this transient-frequency domain method is applied to sound propagation in a 2D hard wall duct with plug flow.

  1. Design and implementation of an omni-directional underwater acoustic micro-modem based on a low-power micro-controller unit.

    PubMed

    Won, Tae-Hee; Park, Sung-Joon

    2012-01-01

    For decades, underwater acoustic communication has been restricted to the point-to-point long distance applications such as deep sea probes and offshore oil fields. For this reason, previous acoustic modems were typically characterized by high data rates and long working ranges at the expense of large size and high power consumption. Recently, as the need for underwater wireless sensor networks (UWSNs) has increased, the research and development of compact and low-power consuming communication devices has become the focus. From the consideration that the requisites of acoustic modems for UWSNs are low power consumption, omni-directional beam pattern, low cost and so on, in this paper, we design and implement an omni-directional underwater acoustic micro-modem satisfying these requirements. In order to execute fast digital domain signal processing and support flexible interfaces with other peripherals, an ARM Cortex-M3 is embedded in the micro-modem. Also, for the realization of small and omni-directional properties, a spherical transducer having a resonant frequency of 70 kHz and a diameter of 34 mm is utilized for the implementation. Physical layer frame format and symbol structure for efficient packet-based underwater communication systems are also investigated. The developed acoustic micro-modem is verified analytically and experimentally in indoor and outdoor environments in terms of functionality and performance. Since the modem satisfies the requirements for use in UWSNs, it could be deployed in a wide range of applications requiring underwater acoustic communication.

  2. Design and Implementation of an Omni-Directional Underwater Acoustic Micro-Modem Based on a Low-Power Micro-Controller Unit

    PubMed Central

    Won, Tae-Hee; Park, Sung-Joon

    2012-01-01

    For decades, underwater acoustic communication has been restricted to the point-to-point long distance applications such as deep sea probes and offshore oil fields. For this reason, previous acoustic modems were typically characterized by high data rates and long working ranges at the expense of large size and high power consumption. Recently, as the need for underwater wireless sensor networks (UWSNs) has increased, the research and development of compact and low-power consuming communication devices has become the focus. From the consideration that the requisites of acoustic modems for UWSNs are low power consumption, omni-directional beam pattern, low cost and so on, in this paper, we design and implement an omni-directional underwater acoustic micro-modem satisfying these requirements. In order to execute fast digital domain signal processing and support flexible interfaces with other peripherals, an ARM Cortex-M3 is embedded in the micro-modem. Also, for the realization of small and omni-directional properties, a spherical transducer having a resonant frequency of 70 kHz and a diameter of 34 mm is utilized for the implementation. Physical layer frame format and symbol structure for efficient packet-based underwater communication systems are also investigated. The developed acoustic micro-modem is verified analytically and experimentally in indoor and outdoor environments in terms of functionality and performance. Since the modem satisfies the requirements for use in UWSNs, it could be deployed in a wide range of applications requiring underwater acoustic communication. PMID:22438765

  3. Stability analysis and design of time-domain acoustic impedance boundary conditions for lined duct with mean flow.

    PubMed

    Liu, Xin; Huang, Xun; Zhang, Xin

    2014-11-01

    This work develops the so-called compensated impedance boundary conditions that enable stable time domain simulations of sound propagation in a lined duct with uniform mean flow, which has important practical interest for noise emission by aero-engines. The proposed method is developed analytically from an unusual perspective of control that shows impedance boundary conditions act as closed-loop feedbacks to an overall duct acoustic system. It turns out that those numerical instabilities of time domain simulations are caused by deficient phase margins of the corresponding control-oriented model. A particular instability of very low frequencies in the presence of steady uniform background mean flow, in addition to the well known high frequency numerical instabilities at the grid size, can be identified using this analysis approach. Stable time domain impedance boundary conditions can be formulated by including appropriate phaselead compensators to achieve desired phase margins. The compensated impedance boundary conditions can be simply designed with no empirical parameter, straightforwardly integrated with ordinary linear acoustic models, and efficiently calculated with no need of resolving sheared boundary layers. The proposed boundary conditions are validated by comparing against asymptotic solutions of spinning modal sound propagation in a duct with a hard-soft interface and reasonable agreement is achieved.

  4. Use of co-combustion bottom ash to design an acoustic absorbing material for highway noise barriers

    SciTech Connect

    Arenas, Celia; Leiva, Carlos; Vilches, Luis F.

    2013-11-15

    Highlights: • The particle size of bottom ash influenced the acoustic behavior of the barrier. • The best sound absorption coefficients were measured for larger particle sizes. • The maximum noise absorption is displaced to lower frequencies for higher thickness. • A noise barrier was designed with better properties than commercial products. • Recycling products from bottom ash no present leaching and radioactivity problems. - Abstract: The present study aims to determine and evaluate the applicability of a new product consisting of coal bottom ash mixed with Portland cement in the application of highway noise barriers. In order to effectively recycle the bottom ash, the influence of the grain particle size of bottom ash, the thickness of the panel and the combination of different layers with various particle sizes have been studied, as well as some environmental properties including leachability (EN-12457-4, NEN-7345) and radioactivity tests. Based on the obtained results, the acoustic properties of the final composite material were similar or even better than those found in porous concrete used for the same application. According to this study, the material produced presented no environmental risk.

  5. Design of automated oil sludge treatment unit

    NASA Astrophysics Data System (ADS)

    Chukhareva, N.; Korotchenko, T.; Yurkin, A.

    2015-11-01

    The article provides the feasibility study of contemporary oil sludge treatment methods. The basic parameters of a new resource-efficient oil sludge treatment unit that allows extracting as much oil as possible and disposing other components in efficient way have been outlined. Based on the calculation results, it has been revealed that in order to reduce the cost of the treatment unit and the expenses related to sludge disposal, it is essential to apply various combinations of the existing treatment methods.

  6. Development of a Liner Design Methodology and Relevant Results of Acoustic Suppression in the Farfield for Mixer-Ejector Nozzles

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.

    2006-01-01

    We have developed a process to predict noise field interior to the ejector and in the farfield for any liner design for a mixer-ejector of arbitrary scale factor. However, a number of assumptions, not verified for the current application, utilized in this process, introduce uncertainties in the final result, especially, on a quantitative basis. The normal impedance model for bulk with perforated facesheet is based on homogeneous foam materials of low resistivity. The impact of flow conditions for HSCT application as well as the impact of perforated facesheet on predicted impedance is not properly accounted. Based on the measured normal impedance for deeper bulk samples (i.e., 2.0 in.) the predicted reactance is much higher compared to the data at frequencies above 2 kHz for T-foam and 200 ppi SiC. The resistance is under predicted at lower frequencies (below 4 kHz) for these samples. Thus, the use of such predicted data in acoustic suppression is likely to introduce inaccuracies. It should be noted that the impedance prediction methods developed recently under liner technology program are not utilized in the studies described in this report due to the program closeout. Acoustic suppression prediction is based on the uniform flow and temperature conditions in a two-sided treated constant area rectangular duct. In addition, assumptions of equal energy per mode noise field and interaction of all frequencies with the treated surface for the entire ejector length may not be accurate. While, the use of acoustic transfer factor minimizes the inaccuracies associated with the prediction for a known test case, the assumption of the same factor for other liner designs and with different linear scale factor ejectors seems to be very optimistic. As illustrated in appendix D that the predicted noise suppression for LSM-1 is lower compared to the measured data is an indication of the above argument. However, the process seems to be more reliable when used for the same scale

  7. AST Launch Vehicle Acoustics

    NASA Technical Reports Server (NTRS)

    Houston, Janice; Counter, D.; Giacomoni, D.

    2015-01-01

    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

  8. Laboratory test and acoustic analysis of cabin treatment for propfan test assessment aircraft

    NASA Technical Reports Server (NTRS)

    Kuntz, H. L.; Gatineau, R. J.

    1991-01-01

    An aircraft cabin acoustic enclosure, built in support of the Propfan Test Assessment (PTA) program, is described. Helmholtz resonators were attached to the cabin trim panels to increase the sidewall transmission loss (TL). Resonators (448) were located between the trim panels and fuselage shell. In addition, 152 resonators were placed between the enclosure and aircraft floors. The 600 resonators were each tuned to a 235 Hz resonance frequency. After flight testing on the PTA aircraft, the enclosure was tested in the Kelly Johnson R and D Center Acoustics Lab. Laboratory noise reduction (NR) test results are discussed. The enclosure was placed in a Gulfstream 2 fuselage section. Broadband (138 dB overall SPL) and tonal (149 dB overall SPL) excitations were used in the lab. Tonal excitation simulated the propfan flight test excitation. The fundamental tone was stepped in 2 Hz intervals from 225 through 245 Hz. The resonators increase the NR of the cabin walls around the resonance frequency of the resonator array. The effects of flanking, sidewall absorption, cabin adsorption, resonator loading of trim panels, and panel vibrations are presented. Increases in NR of up to 11 dB were measured.

  9. Cochlear bionic acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan

    2014-11-01

    A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole.

  10. SmEdA vibro-acoustic modelling in the mid-frequency range including the effect of dissipative treatments

    NASA Astrophysics Data System (ADS)

    Hwang, H. D.; Maxit, L.; Ege, K.; Gerges, Y.; Guyader, J.-L.

    2017-04-01

    Vibro-acoustic simulation in the mid-frequency range is of interest for automotive and truck constructors. The dissipative treatments used for noise and vibration control such as viscoelastic patches and acoustic absorbing materials must be taken into account in the problem. The Statistical modal Energy distribution Analysis (SmEdA) model consists in extending Statistical Energy Analysis (SEA) to the mid-frequency range by establishing power balance equations between the modes of the different subsystems. The modal basis of uncoupled-subsystems that can be estimated by the finite element method in the mid-frequency range is used as input data. SmEdA was originally developed by considering constant modal damping factors for each subsystem. However, this means that it cannot describe the local distribution of dissipative materials. To overcome this issue, a methodology is proposed here to take into account the effect of these materials. This methodology is based on the finite element models of the subsystems that include well-known homogenized material models of dissipative treatments. The Galerkin method with subsystem normal modes is used to estimate the modal damping loss factors. Cross-modal coupling terms which appear in the formulation due to the dissipative materials are assumed to be negligible. An approximation of the energy sharing between the subsystems damped by dissipative materials is then described by SmEdA. The different steps of the method are validated experimentally by applying it to a laboratory test case composed of a plate-cavity system with different configurations of dissipative treatments. The comparison between the experimental and the simulation results shows good agreement in the mid-frequency range.

  11. Acoustic dispersive prism

    NASA Astrophysics Data System (ADS)

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  12. Acoustic dispersive prism.

    PubMed

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R

    2016-01-07

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  13. Acoustic dispersive prism

    PubMed Central

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium. PMID:26739504

  14. Structural-acoustic optimum design of shell structures in open/closed space based on a free-form optimization method

    NASA Astrophysics Data System (ADS)

    Shimoda, Masatoshi; Shimoide, Kensuke; Shi, Jin-Xing

    2016-03-01

    Noise reduction by structural geometry optimization has attracted much attention among designers. In the present work, we propose a free-form optimization method for the structural-acoustic design optimization of shell structures to reduce the noise of a targeted frequency or frequency range in an open or closed space. The objective of the design optimization is to minimize the average structural vibration-induced sound pressure at the evaluation points in the acoustic field under a volume constraint. For the shape design optimization, we carry out structural-acoustic coupling analysis and adjoint analysis to calculate the shape gradient functions. Then, we use the shape gradient functions in velocity analysis to update the shape of shell structures. We repeat this process until convergence is confirmed to obtain the optimum shape of the shell structures in a structural-acoustic coupling system. The numerical results for the considered examples showed that the proposed design optimization process can significantly reduce the noise in both open and closed spaces.

  15. THE BARYON ACOUSTIC OSCILLATION BROADBAND AND BROAD-BEAM ARRAY: DESIGN OVERVIEW AND SENSITIVITY FORECASTS

    SciTech Connect

    Pober, Jonathan C.; Parsons, Aaron R.; McQuinn, Matthew; Ali, Zaki; DeBoer, David R.; McDonald, Patrick; Aguirre, James E.; Bradley, Richard F.; Chang, Tzu-Ching; Morales, Miguel F.

    2013-03-15

    This work describes a new instrument optimized for a detection of the neutral hydrogen 21 cm power spectrum between redshifts of 0.5 and 1.5: the Baryon Acoustic Oscillation Broadband and Broad-beam (BAOBAB) array. BAOBAB will build on the efforts of a first generation of 21 cm experiments that are targeting a detection of the signal from the Epoch of Reionization at z {approx} 10. At z {approx} 1, the emission from neutral hydrogen in self-shielded overdense halos also presents an accessible signal, since the dominant, synchrotron foreground emission is considerably fainter than at redshift 10. The principle science driver for these observations are baryon acoustic oscillations in the matter power spectrum which have the potential to act as a standard ruler and constrain the nature of dark energy. BAOBAB will fully correlate dual-polarization antenna tiles over the 600-900 MHz band with a frequency resolution of 300 kHz and a system temperature of 50 K. The number of antennas will grow in staged deployments, and reconfigurations of the array will allow for both traditional imaging and high power spectrum sensitivity operations. We present calculations of the power spectrum sensitivity for various array sizes, with a 35 element array measuring the cosmic neutral hydrogen fraction as a function of redshift, and a 132 element system detecting the BAO features in the power spectrum, yielding a 1.8% error on the z {approx} 1 distance scale, and, in turn, significant improvements to constraints on the dark energy equation of state over an unprecedented range of redshifts from {approx}0.5 to 1.5.

  16. Acoustic telemetry and network analysis reveal the space use of multiple reef predators and enhance marine protected area design.

    PubMed

    Lea, James S E; Humphries, Nicolas E; von Brandis, Rainer G; Clarke, Christopher R; Sims, David W

    2016-07-13

    Marine protected areas (MPAs) are commonly employed to protect ecosystems from threats like overfishing. Ideally, MPA design should incorporate movement data from multiple target species to ensure sufficient habitat is protected. We used long-term acoustic telemetry and network analysis to determine the fine-scale space use of five shark and one turtle species at a remote atoll in the Seychelles, Indian Ocean, and evaluate the efficacy of a proposed MPA. Results revealed strong, species-specific habitat use in both sharks and turtles, with corresponding variation in MPA use. Defining the MPA's boundary from the edge of the reef flat at low tide instead of the beach at high tide (the current best in Seychelles) significantly increased the MPA's coverage of predator movements by an average of 34%. Informed by these results, the larger MPA was adopted by the Seychelles government, demonstrating how telemetry data can improve shark spatial conservation by affecting policy directly.

  17. Methods for the treatment of acoustic and absorptive/dispersive wave field measurements

    NASA Astrophysics Data System (ADS)

    Innanen, Kristopher Albert Holm

    Many recent methods of seismic wave field processing and inversion concern themselves with the fine detail of the amplitude and phase characteristics of measured events. Processes of absorption and dispersion have a strong impact on both; the impact is particularly deleterious to the effective resolution of images created from the data. There is a need to understand the dissipation of seismic wave energy as it affects such methods. I identify: algorithms based on the inverse scattering series, algorithms based on multiresolution analysis, and algorithms based on the estimation of the order of the singularities of seismic data, as requiring this kind of study. As it turns out, these approaches may be cast such that they deal directly with issues of attenuation, to the point where they can be seen as tools for viscoacoustic forward modelling, Q estimation; viscoacoustic inversion, and/or Q compensation. In this thesis I demonstrate these ideas in turn. The forward scattering series is formulated such that a viscoacoustic wave field is represented as an expansion about an acoustic reference; analysis of the convergence properties and scattering diagrams are carried out, and it is shown that (i) the attenuated wave field may be generated by the nonlinear interplay of acoustic reference fields, and (ii) the cumulative effect of certain scattering types is responsible for macroscopic wave field properties: also, the basic form of the absorptive/dispersive inversion problem is predicted. Following this, the impact of Q on measurements of the local regularity of a seismic trace, via Lipschitz exponents, is discussed, with the aim of using these exponents as a means to estimate local Q values. The problem of inverse scattering based imaging and inversion is treated next: I present a simple, computable form for the simultaneous imaging and wavespeed inversion of 1D acoustic wave field data. This method is applied to 1D, normal incidence synthetic data: its sensitivity with

  18. Fundamentals of Acoustics. Psychoacoustics and Hearing. Acoustical Measurements

    NASA Technical Reports Server (NTRS)

    Begault, Durand R.; Ahumada, Al (Technical Monitor)

    1997-01-01

    These are 3 chapters that will appear in a book titled "Building Acoustical Design", edited by Charles Salter. They are designed to introduce the reader to fundamental concepts of acoustics, particularly as they relate to the built environment. "Fundamentals of Acoustics" reviews basic concepts of sound waveform frequency, pressure, and phase. "Psychoacoustics and Hearing" discusses the human interpretation sound pressure as loudness, particularly as a function of frequency. "Acoustic Measurements" gives a simple overview of the time and frequency weightings for sound pressure measurements that are used in acoustical work.

  19. Design Seminar for Land Treatment of Municipal Wastewater Effluents.

    ERIC Educational Resources Information Center

    Demirjian, Y. A.

    This document reports the development and operation of a country-wide wastewater treatment program. The program was designed to treat liquid wastewater by biological treatment in aerated lagoons, store it, and then spray irrigate on crop farmland during the growing season. The text discusses the physical design of the system, agricultural aspects,…

  20. PROCESS DESIGN MANUAL: LAND TREATMENT OF MUNICIPAL WASTEWATER

    EPA Science Inventory

    The manual presents a rational procedure for the design of land treatment systems. Slow rate, rapid infiltration, and overland flow processes for the treatment of municipal wastewaters are discussed in detail, and the design concepts and criteria are presented. A two-phased plann...

  1. Design of a radio-linked implantable cochlear prosthesis using surface acoustic wave devices.

    PubMed

    Jeutter, D C; Josse, F

    1993-01-01

    Cochlear prosthesis systems for postlingually deaf individuals (those who have become deaf due to disease or injury after having developed mature speech capability) are considered. These systems require the surgical implantation of an array of electrodes within the cochlea and are driven by processed sound signals from outside the body. A system that uses an analog signal approach for transcutaneous transfer of six processed speech data channels using frequency multiplexing is described. The system utilizes a filterbank of six narrowband surface acoustic wave (SAW) filters in the range 72-78 MHz with a 1.2-MHz channel spacing to multiplex the six carrier signals, frequency modulated, by the processed speech signals, onto a composite signal. The same SAW filters are used in the receiver filterbank for signal separation, but are housed in a miniaturized package. The system includes a portable transmitter and a receiver package which is to be implanted in the patient. The implanted circuits are supplied exclusively from power transferred from outside the body via a separate 10-MHz transcutaneous link.

  2. Numerical acoustic characteristics and optimum design of the pressure reducing valve

    NASA Astrophysics Data System (ADS)

    Guo, P. C.; Sun, L. G.; Sun, S. H.; Feng, J. J.; Wu, K. G.; Luo, X. Q.

    2016-11-01

    The pressure reducing valves are widely used in the technological water supplied ways of gravity flow. A credible pressure reducing valve can provide stable cooling water for units with extremely low maintenance cost and labor intensity in a fairly long period of time. In this paper, a three-dimensional numerical simulation of flow field and acoustic characteristics towards a combined type pressure reducing valve was carried out based on ANSYS Fluent and the FW-H equation. The numerical results achieve the regulation of noise generation, transmission and attenuation. It shows that the sound pressure level of monitoring points seem to be higher and large gradient at low frequencies under the same flow velocity, while it presents reverse results with the increment of frequency and maintains a constant valve finally. At the same time, the monitoring points in the vicinity of throttling cone shows higher sound pressure level and upstream noise is lower than downstream's. Aiming at the problem of valve noise, a modified measure to reduce the flow-induced noise was proposed.

  3. Lobed Mixer Design for Noise Suppression Acoustic and Aerodynamic Test Data Analysis

    NASA Technical Reports Server (NTRS)

    Mengle, Vinod G.; Dalton, William N.; Boyd, Kathleen (Technical Monitor); Bridges, James (Technical Monitor)

    2002-01-01

    A comprehensive database for the acoustic and aerodynamic characteristics of several model-scale lobe mixers of bypass ratio 5 to 6 has been created for mixed jet speeds up to 1080 ft/s at typical take-off (TO) conditions of small-to-medium turbofan engines. The flight effect was simulated for Mach numbers up to 0.3. The static thrust performance and plume data were also obtained at typical TO and cruise conditions. The tests were done at NASA Lewis anechoic dome and ASK's FluiDyne Laboratories. The effect of several lobe mixer and nozzle parameters, such as, lobe scalloping, lobe count, lobe penetration and nozzle length was examined in terms of flyover noise at constant altitude. Sound in the nozzle reference frame was analyzed to understand the source characteristics. Several new concepts, mechanisms and methods are reported for such lobed mixers, such as, "boomerang" scallops, "tongue" mixer, detection of "excess" internal noise sources, and extrapolation of flyover noise data from one flight speed to different flight speeds. Noise reduction of as much as 3 EPNdB was found with a deeply scalloped mixer compared to annular nozzle at net thrust levels of 9500 lb for a 29 in. diameter nozzle after optimizing the nozzle length.

  4. Mechanism of operation and design considerations for surface acoustic wave device vapor sensors

    NASA Astrophysics Data System (ADS)

    Wohltjen, H.

    1984-04-01

    Surface acoustic wave (SAW) devices offer many attractive features for application as vapor phase chemical microsensors. This paper describes the characteristics of SAW devices and techniques by which they can be employed as vapor sensors. The perturbation of SAW amplitude and velocity by polymeric coating films was investigated both theoretically and experimentally. High sensitivity can be achieved when the device is used as the resonating element in a delay line oscillator circuit. A simple equation has been developed from theoretical considerations which offers reasonably accurate quantitative predictions of SAW Device frequency shifts when subjected to a given mass loading. In this mode the SAW device behaves in a fashion very similar to conventional bulk wave quartz crystal microbalance except that the sensitivity can be several orders of magnitude higher and the device size can be several orders of magnitude smaller. Detection of mass changes of less than 1 femtogram by a SAW device having a surface area of 0.0001 square cm. is theoretically possible.

  5. Bench to Bedside: Understanding Symptom Response to Acupuncture Treatment and Designing a Successful Acupuncture Treatment Program

    DTIC Science & Technology

    2015-10-01

    AWARD NUMBER: W81XWH-14-1-0533 TITLE: Bench to Bedside: Understanding Symptom Response to Acupuncture Treatment and Designing a Successful... Acupuncture Treatment Program PRINCIPAL INVESTIGATOR: Dr. Lisa Conboy CONTRACTING ORGANIZATION: New England School of Acupuncture ...Understanding Symptom Response to 5a. CONTRACT NUMBER Acupuncture Treatment and Designing a Successful Acupuncture 5b. GRANT NUMBER W81XWH-14-1-0533

  6. Design and optimization of a noise reduction system for infrasonic measurements using elements with low acoustic impedance.

    PubMed

    Alcoverro, Benoit; Le Pichon, Alexis

    2005-04-01

    The implementation of the infrasound network of the International Monitoring System (IMS) for the enforcement of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) increases the effort in the design of suitable noise reducer systems. In this paper we present a new design consisting of low impedance elements. The dimensioning and the optimization of this discrete mechanical system are based on numerical simulations, including a complete electroacoustical modeling and a realistic wind-noise model. The frequency response and the noise reduction obtained for a given wind speed are compared to statistical noise measurements in the [0.02-4] Hz frequency band. The effects of the constructive parameters-the length of the pipes, inner diameters, summing volume, and number of air inlets-are investigated through a parametric study. The studied system consists of 32 air inlets distributed along an overall diameter of 16 m. Its frequency response is flat up to 4 Hz. For a 2 m/s wind speed, the maximal noise reduction obtained is 15 dB between 0.5 and 4 Hz. At lower frequencies, the noise reduction is improved by the use of a system of larger diameter. The main drawback is the high-frequency limitation introduced by acoustical resonances inside the pipes.

  7. Virtual acoustics displays

    NASA Technical Reports Server (NTRS)

    Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

    1991-01-01

    The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

  8. Virtual acoustics displays

    NASA Astrophysics Data System (ADS)

    Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

    1991-03-01

    The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

  9. 9x15 Low Speed Wind Tunnel Acoustic Improvements

    NASA Technical Reports Server (NTRS)

    Stark, David; Stephens, David

    2016-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) at NASA Glenn Research Center was built in 1969 in the return leg of the 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT). The 8x6 SWT was completed in 1949 and acoustically treated to mitigate community noise issues in 1950. This treatment included the addition of a large muffler downstream of the 8x6 SWT test section and diffuser. The 9x15 LSWT was designed for performance testing of VSTOL aircraft models, but with the addition of the current acoustic treatment in 1986 the tunnel has been used principally for acoustic and performance testing of aircraft propulsions systems. The present document describes an anticipated acoustic upgrade to be completed in 2017.

  10. Tuned Chamber Core Panel Acoustic Test Results

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Allen, Albert R.

    2016-01-01

    This report documents acoustic testing of tuned chamber core panels, which can be used to supplement the low-frequency performance of conventional acoustic treatment. The tuned chamber core concept incorporates low-frequency noise control directly within the primary structure and is applicable to sandwich constructions with a directional core, including corrugated-, truss-, and fluted-core designs. These types of sandwich structures have long, hollow channels (or chambers) in the core. By adding small holes through one of the facesheets, the hollow chambers can be utilized as an array of low-frequency acoustic resonators. These resonators can then be used to attenuate low-frequency noise (below 400 Hz) inside a vehicle compartment without increasing the weight or size of the structure. The results of this test program demonstrate that the tuned chamber core concept is effective when used in isolation or combined with acoustic foam treatments. Specifically, an array of acoustic resonators integrated within the core of the panels was shown to improve both the low-frequency absorption and transmission loss of the structure in targeted one-third octave bands.

  11. Acoustic Neuroma

    MedlinePlus

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

  12. Science 101: How Do Acoustics Dictate the Design of a Concert Hall?

    ERIC Educational Resources Information Center

    Robertson, Bill

    2015-01-01

    This column provides background science information for elementary teachers. When the author was young he used to think that the ideal design for a concert hall would contain walls that were composed of sound-absorbing material, like foam or egg cartons or such. He noticed, though, that this was not the case. Most concert halls contain curtains…

  13. Core Noise: Implications of Emerging N+3 Designs and Acoustic Technology Needs

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.

    2011-01-01

    This presentation is a summary of the core-noise implications of NASA's primary N+3 aircraft concepts. These concepts are the MIT/P&W D8.5 Double Bubble design, the Boeing/GE SUGAR Volt hybrid gas-turbine/electric engine concept, the NASA N3-X Turboelectric Distributed Propulsion aircraft, and the NASA TBW-XN Truss-Braced Wing concept. The first two are future concepts for the Boeing 737/Airbus A320 US transcontinental mission of 180 passengers and a maximum range of 3000 nm. The last two are future concepts for the Boeing 777 transpacific mission of 350 passengers and a 7500 nm range. Sections of the presentation cover: turbofan design trends on the N+1.5 time frame and the already emerging importance of core noise; the NASA N+3 concepts and associated core-noise challenges; the historical trends for the engine bypass ratio (BPR), overall pressure ratio (OPR), and combustor exit temperature; and brief discussion of a noise research roadmap being developed to address the core-noise challenges identified for the N+3 concepts. The N+3 conceptual aircraft have (i) ultra-high bypass ratios, in the rage of 18 - 30, accomplished by either having a small-size, high-power-density core, an hybrid design which allows for an increased fan size, or by utilizing a turboelectric distributed propulsion design; and (ii) very high OPR in the 50 - 70 range. These trends will elevate the overall importance of turbomachinery core noise. The N+3 conceptual designs specify the need for the development and application of advanced liners and passive and active control strategies to reduce the core noise. Current engineering prediction of core noise uses semi-empirical methods based on older turbofan engines, with (at best) updates for more recent designs. The models have not seen the same level of development and maturity as those for fan and jet noise and are grossly inadequate for the designs considered for the N+3 time frame. An aggressive program for the development of updated noise

  14. PROCESS DESIGN MANUAL FOR LAND TREATMENT OF MUNICIPAL WASTEWATER

    EPA Science Inventory

    The USEPA guidance on land treatment of municipal and industrial wastewater is updated for the first time since 1984. The significant new technilogical changes include phytoremediation, vadose zone monitoring, new design approaches to surface irrigation, center pivot irrigation,...

  15. Manipulate acoustic waves by impedance matched acoustic metasurfaces

    NASA Astrophysics Data System (ADS)

    Wu, Ying; Mei, Jun; Aljahdali, Rasha

    We design a type of acoustic metasurface, which is composed of carefully designed slits in a rigid thin plate. The effective refractive indices of different slits are different but the impedances are kept the same as that of the host medium. Numerical simulations show that such a metasurface can redirect or reflect a normally incident wave at different frequencies, even though it is impedance matched to the host medium. We show that the underlying mechanisms can be understood by using the generalized Snell's law, and a unified analytic model based on mode-coupling theory. We demonstrate some simple realization of such acoustic metasurface with real materials. The principle is also extended to the design of planar acoustic lens which can focus acoustic waves. Manipulate acoustic waves by impedance matched acoustic metasurfaces.

  16. Acoustic Seaglider

    DTIC Science & Technology

    2008-03-07

    a national naval responsibility. Acoustic sensors on mobile, autonomous platforms will enable basic research topics on temporal and spatial...problem and acoustic navigation and communications within the context of distributed autonomous persistent undersea surveillance sensor networks...Acoustic sensors on mobile, autonomous platforms will enable basic research topics on temporal and spatial coherence and the description of ambient

  17. 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.

  18. 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.

  19. The Acoustic Lens Design and in Vivo Use of a Multifunctional Catheter Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

    PubMed Central

    Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Sahn, David

    2009-01-01

    A multifunctional 9F intracardiac imaging and electrophysiology mapping catheter was developed and tested to help guide diagnostic and therapeutic intracardiac electrophysiology (EP) procedures. The catheter tip includes a 7.25-MHz, 64-element, side-looking phased array for high resolution sector scanning. Multiple electrophysiology mapping sensors were mounted as ring electrodes near the array for electrocardiographic synchronization of ultrasound images. The catheter array elevation beam performance in particular was investigated. An acoustic lens for the distal tip array designed with a round cross section can produce an acceptable elevation beam shape; however, the velocity of sound in the lens material should be approximately 155 m/s slower than in tissue for the best beam shape and wide bandwidth performance. To help establish the catheter’s unique ability for integration with electrophysiology interventional procedures, it was used in vivo in a porcine animal model, and demonstrated both useful intracardiac echocardiographic visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheter also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. PMID:18407850

  20. Acoustic iridescence.

    PubMed

    Cox, Trevor J

    2011-03-01

    An investigation has been undertaken into acoustic iridescence, exploring how a device can be constructed which alter sound waves, in a similar way to structures in nature that act on light to produce optical iridescence. The main construction had many thin perforated sheets spaced half a wavelength apart for a specified design frequency. The sheets create the necessary impedance discontinuities to create backscattered waves, which then interfere to create strongly reflected sound at certain frequencies. Predictions and measurements show a set of harmonics, evenly spaced in frequency, for which sound is reflected strongly. And the frequency of these harmonics increases as the angle of observation gets larger, mimicking the iridescence seen in natural optical systems. Similar to optical systems, the reflections become weaker for oblique angles of reflection. A second construction was briefly examined which exploited a metamaterial made from elements and inclusions which were much smaller than the wavelength. Boundary element method predictions confirmed the potential for creating acoustic iridescence from layers of such a material.

  1. PRSEUS Acoustic Panel Fabrication

    NASA Technical Reports Server (NTRS)

    Nicolette, Velicki; Yovanof, Nicolette P.; Baraja, Jaime; Mathur, Gopal; Thrash, Patrick; Pickell, Robert

    2011-01-01

    This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration with regards to acoustic response. A PRSEUS panel was designed and fabricated and provided to NASA-LaRC for acoustic response testing in the Structural Acoustics Loads and Transmission (SALT) facility). Preliminary assessments of the sound transmission characteristics of a PRSEUS panel subjected to a representative Hybrid Wing Body (HWB) operating environment were completed for the NASA Environmentally Responsible Aviation (ERA) Program.

  2. Treatment of a sloping fluid-solid interface and sediment layering with the seismo-acoustic parabolic equation.

    PubMed

    Collins, Michael D; Siegmann, William L

    2015-01-01

    The parabolic equation method is extended to handle problems in seismo-acoustics that have multiple fluid and solid layers, continuous depth dependence within layers, and sloping interfaces between layers. The medium is approximated in terms of a series of range-independent regions, and a single-scattering approximation is used to compute transmitted fields across the vertical interfaces between regions. The approach is implemented in terms of a set of dependent variables that is well suited to piecewise continuous depth dependence in the elastic parameters, but one of the fluid-solid interface conditions in that formulation involves a second derivative that complicates the treatment of sloping interfaces. This issue is resolved by using a non-centered, four-point difference formula for the second derivative. The approach is implemented using a matrix decomposition that is efficient when the parameters of the medium have a general dependence within the upper layers of the sediment but only depend on depth in the water column and deep within the sediment.

  3. Acoustically Induced Vibration of Structures: Reverberant Vs. Direct Acoustic Testing

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.; O'Connell, Michael R.; Tsoi, Wan B.

    2009-01-01

    Large reverberant chambers have been used for several decades in the aerospace industry to test larger structures such as solar arrays and reflectors to qualify and to detect faults in the design and fabrication of spacecraft and satellites. In the past decade some companies have begun using direct near field acoustic testing, employing speakers, for qualifying larger structures. A limited test data set obtained from recent acoustic tests of the same hardware exposed to both direct and reverberant acoustic field testing has indicated some differences in the resulting structural responses. In reverberant acoustic testing, higher vibration responses were observed at lower frequencies when compared with the direct acoustic testing. In the case of direct near field acoustic testing higher vibration responses appeared to occur at higher frequencies as well. In reverberant chamber testing and direct acoustic testing, standing acoustic modes of the reverberant chamber or the speakers and spacecraft parallel surfaces can strongly couple with the fundamental structural modes of the test hardware. In this paper data from recent acoustic testing of flight hardware, that yielded evidence of acoustic standing wave coupling with structural responses, are discussed in some detail. Convincing evidence of the acoustic standing wave/structural coupling phenomenon will be discussed, citing observations from acoustic testing of a simple aluminum plate. The implications of such acoustic coupling to testing of sensitive flight hardware will be discussed. The results discussed in this paper reveal issues with over or under testing of flight hardware that could pose unanticipated structural and flight qualification issues. Therefore, it is of paramount importance to understand the structural modal coupling with standing acoustic waves that has been observed in both methods of acoustic testing. This study will assist the community to choose an appropriate testing method and test setup in

  4. Noise in small portable motocompressors. Experiments on limited-cost acoustic treatments to obtain progressive improvements

    NASA Astrophysics Data System (ADS)

    Collober, J.; Corlay, B.

    1984-04-01

    Design modifications are proposed in order to help motocompressor manufacturers to reduce the noise level to 85 dBA. Work on 8kW groups shows that the noise sources are, in order of importance, the internal combustion motor exhaust, the air inlet, the cooling air circuit and the oil pan. The effects of an inlet air filter, an exhaust noise attenuator and a cover on the motocompressor are discussed. A noise reduction of 10dBA is obtained.

  5. Twenty years' experience in the treatment of acoustic neuromas with fractionated radiotherapy: A review of 45 cases

    SciTech Connect

    Maire, Jean-Philippe . E-mail: jean-philippe.maire@chu-bordeaux.fr; Huchet, Aymeri; Milbeo, Yann; Darrouzet, Vincent; Causse, Nicole; Celerier, Denis; Liguoro, Dominique; Bebear, Jean-Pierre

    2006-09-01

    Purpose: To evaluate very long-term results of fractionated radiotherapy (FRT) of acoustic neuromas (AN). Methods and Materials: From January 1986 to January 2004, FRT was performed in 45 consecutive patients (46 AN). Indications were as follows: poor general condition contraindicating surgery, hearing preservation in bilateral neuromas, partial resection, nonsurgical recurrence. A 3-field to 5-field technique with static beams was used. A mean total dose of 51 Gy was given (1.80 Gy/fraction). The median tumor diameter was 31 mm (range, 11-55 mm). The median follow-up from FRT was 80 months (range, 4-227 months). Results: The particularity of our series consists of a very long-term follow-up of FRT given to selected patients. Nineteen patients died, two with progressive disease, and 17 from non-AN causes. A serviceable level of hearing was preserved in 7/9 hearing patients. No patient had facial or trigeminal neuropathy. Tumor shrinkage was observed in 27 (59%) and stable disease in 16 (35%). Tumor progression occurred in three patients, 12 to 15 months after FRT. Two additional tumors recurred after shrinkage 20 and 216 months after treatment and were operated on. Actuarial local tumor control rates at 5 and 15 years were 86%. For the patient who had a tumor recurrence at 216 months, histologic examination documented transformation to a low-grade malignant peripheral nerve sheath tumor. Conclusion: Very long-term efficacy of FRT is well documented in this series. However, our results suggest that malignant transformation can occur many years after FRT so we advocate caution when using this treatment for young patients.

  6. Modeling, design, packing and experimental analysis of liquid-phase shear-horizontal surface acoustic wave sensors

    NASA Astrophysics Data System (ADS)

    Pollard, Thomas B

    Recent advances in microbiology, computational capabilities, and microelectromechanical-system fabrication techniques permit modeling, design, and fabrication of low-cost, miniature, sensitive and selective liquid-phase sensors and lab-on-a-chip systems. Such devices are expected to replace expensive, time-consuming, and bulky laboratory-based testing equipment. Potential applications for devices include: fluid characterization for material science and industry; chemical analysis in medicine and pharmacology; study of biological processes; food analysis; chemical kinetics analysis; and environmental monitoring. When combined with liquid-phase packaging, sensors based on surface-acoustic-wave (SAW) technology are considered strong candidates. For this reason such devices are focused on in this work; emphasis placed on device modeling and packaging for liquid-phase operation. Regarding modeling, topics considered include mode excitation efficiency of transducers; mode sensitivity based on guiding structure materials/geometries; and use of new piezoelectric materials. On packaging, topics considered include package interfacing with SAW devices, and minimization of packaging effects on device performance. In this work novel numerical models are theoretically developed and implemented to study propagation and transduction characteristics of sensor designs using wave/constitutive equations, Green's functions, and boundary/finite element methods. Using developed simulation tools that consider finite-thickness of all device electrodes, transduction efficiency for SAW transducers with neighboring uniform or periodic guiding electrodes is reported for the first time. Results indicate finite electrode thickness strongly affects efficiency. Using dense electrodes, efficiency is shown to approach 92% and 100% for uniform and periodic electrode guiding, respectively; yielding improved sensor detection limits. A numerical sensitivity analysis is presented targeting viscosity

  7. Scale Model Thruster Acoustic Measurement Results

    NASA Technical Reports Server (NTRS)

    Kenny, R. Jeremy; Vargas, Magda B.

    2013-01-01

    Subscale rocket acoustic data is used to predict acoustic environments for full scale rockets. Over the last several years acoustic data has been collected during horizontal tests of solid rocket motors. Space Launch System (SLS) Scale Model Acoustic Test (SMAT) was designed to evaluate the acoustics of the SLS vehicle including the liquid engines and solid rocket boosters. SMAT is comprised of liquid thrusters scalable to the Space Shuttle Main engines (SSME) and Rocket Assisted Take Off (RATO) motors scalable to the 5-segment Reusable Solid Rocket Motor (RSTMV). Horizontal testing of the liquid thrusters provided an opportunity to collect acoustic data from liquid thrusters to characterize the acoustic environments. Acoustic data was collected during the horizontal firings of a single thruster and a 4-thruster (Quad) configuration. Presentation scope. Discuss the results of the single and 4-thruster acoustic measurements. Compare the measured acoustic levels of the liquid thrusters to the Solid Rocket Test Motor V - Nozzle 2 (SRTMV-N2).

  8. Active Control of Fan Noise-Feasibility Study. Volume 2: Canceling Noise Source-Design of an Acoustic Plate Radiator Using Piezoceramic Actuators

    NASA Technical Reports Server (NTRS)

    Pla, F. G.; Rajiyah, H.

    1995-01-01

    The feasibility of using acoustic plate radiators powered by piezoceramic thin sheets as canceling sources for active control of aircraft engine fan noise is demonstrated. Analytical and numerical models of actuated beams and plates are developed and validated. An optimization study is performed to identify the optimum combination of design parameters that maximizes the plate volume velocity for a given resonance frequency. Fifteen plates with various plate and actuator sizes, thicknesses, and bonding layers were fabricated and tested using results from the optimization study. A maximum equivalent piston displacement of 0.39 mm was achieved with the optimized plate samples tested with only one actuator powered, corresponding to a plate deflection at the center of over 1 millimeter. This is very close to the deflection required for a full size engine application and represents a 160-fold improvement over previous work. Experimental results further show that performance is limited by the critical stress of the piezoceramic actuator and bonding layer rather than by the maximum moment available from the actuator. Design enhancements are described in detail that will lead to a flight-worthy acoustic plate radiator by minimizing actuator tensile stresses and reducing nonlinear effects. Finally, several adaptive tuning methods designed to increase the bandwidth of acoustic plate radiators are analyzed including passive, active, and semi-active approaches. The back chamber pressurization and volume variation methods are investigated experimentally and shown to be simple and effective ways to obtain substantial control over the resonance frequency of a plate radiator. This study shows that piezoceramic-based plate radiators can be a viable acoustic source for active control of aircraft engine fan noise.

  9. Pricing Mechanism Design for Centralized Pollutant Treatment with SME Alliances

    PubMed Central

    Li, Yuyu; Huang, Bo; Tao, Fengming

    2016-01-01

    In this paper, we assume that a professional pollutant treatment enterprise treats all of the pollutants emitted by multiple small and medium-sized enterprises (SMEs). In order to determine the treatment price, SMEs can bargain with the pollutant treatment enterprise individually, or through forming alliances. We propose a bargaining game model of centralized pollutant treatment to study how the pollutant treatment price is determined through negotiation. Then, we consider that there is a moral hazard from SMEs in centralized pollutant treatment; in other words, they may break their agreement concerning their quantities of production and pollutant emissions with the pollutant treatment enterprise. We study how the pollutant treatment enterprise can prevent this by pricing mechanism design. It is found that the pollutant treatment enterprise can prevent SMEs’ moral hazard through tiered pricing. If the marginal treatment cost of the pollutant treatment enterprise is a constant, SMEs could bargain with the pollutant treatment enterprise individually, otherwise, they should form a grand alliance to bargain with it as a whole. PMID:27338440

  10. Pricing Mechanism Design for Centralized Pollutant Treatment with SME Alliances.

    PubMed

    Li, Yuyu; Huang, Bo; Tao, Fengming

    2016-06-22

    In this paper, we assume that a professional pollutant treatment enterprise treats all of the pollutants emitted by multiple small and medium-sized enterprises (SMEs). In order to determine the treatment price, SMEs can bargain with the pollutant treatment enterprise individually, or through forming alliances. We propose a bargaining game model of centralized pollutant treatment to study how the pollutant treatment price is determined through negotiation. Then, we consider that there is a moral hazard from SMEs in centralized pollutant treatment; in other words, they may break their agreement concerning their quantities of production and pollutant emissions with the pollutant treatment enterprise. We study how the pollutant treatment enterprise can prevent this by pricing mechanism design. It is found that the pollutant treatment enterprise can prevent SMEs' moral hazard through tiered pricing. If the marginal treatment cost of the pollutant treatment enterprise is a constant, SMEs could bargain with the pollutant treatment enterprise individually, otherwise, they should form a grand alliance to bargain with it as a whole.

  11. A Brief History of Acoustics

    NASA Astrophysics Data System (ADS)

    Rossing, Thomas

    Although there are certainly some good historical treatments of acoustics in the literature, it still seems appropriate to begin a handbook of acoustics with a brief history of the subject. We begin by mentioning some important experiments that took place before the 19th century. Acoustics in the 19th century is characterized by describing the work of seven outstanding acousticians: Tyndall, von Helmholtz, Rayleigh, Stokes, Bell, Edison, and Koenig. Of course this sampling omits the mention of many other outstanding investigators.

  12. Capabilities, Design, Construction and Commissioning of New Vibration, Acoustic, and Electromagnetic Capabilities Added to the World's Largest Thermal Vacuum Chamber at NASA's Space Power Facility

    NASA Technical Reports Server (NTRS)

    Motil, Susan M.; Ludwiczak, Damian R.; Carek, Gerald A.; Sorge, Richard N.; Free, James M.; Cikanek, Harry A., III

    2011-01-01

    NASA s human space exploration plans developed under the Exploration System Architecture Studies in 2005 included a Crew Exploration Vehicle launched on an Ares I launch vehicle. The mass of the Crew Exploration Vehicle and trajectory of the Ares I coupled with the need to be able to abort across a large percentage of the trajectory generated unprecedented testing requirements. A future lunar lander added to projected test requirements. In 2006, the basic test plan for Orion was developed. It included several types of environment tests typical of spacecraft development programs. These included thermal-vacuum, electromagnetic interference, mechanical vibration, and acoustic tests. Because of the size of the vehicle and unprecedented acoustics, NASA conducted an extensive assessment of options for testing, and as result, chose to augment the Space Power Facility at NASA Plum Brook Station, of the John H. Glenn Research Center to provide the needed test capabilities. The augmentation included designing and building the World s highest mass capable vibration table, the highest power large acoustic chamber, and adaptation of the existing World s largest thermal vacuum chamber as a reverberant electromagnetic interference test chamber. These augmentations were accomplished from 2007 through early 2011. Acceptance testing began in Spring 2011 and will be completed in the Fall of 2011. This paper provides an overview of the capabilities, design, construction and acceptance of this extraordinary facility.

  13. Designing acoustics for linguistically diverse classrooms: Effects of background noise, reverberation and talker foreign accent on speech comprehension by native and non-native English-speaking listeners

    NASA Astrophysics Data System (ADS)

    Peng, Zhao Ellen

    The current classroom acoustics standard (ANSI S12.60-2010) recommends core learning spaces not to exceed background noise level (BNL) of 35 dBA and reverberation time (RT) of 0.6 second, based on speech intelligibility performance mainly by the native English-speaking population. Existing literature has not correlated these recommended values well with student learning outcomes. With a growing population of non-native English speakers in American classrooms, the special needs for perceiving degraded speech among non-native listeners, either due to realistic room acoustics or talker foreign accent, have not been addressed in the current standard. This research seeks to investigate the effects of BNL and RT on the comprehension of English speech from native English and native Mandarin Chinese talkers as perceived by native and non-native English listeners, and to provide acoustic design guidelines to supplement the existing standard. This dissertation presents two studies on the effects of RT and BNL on more realistic classroom learning experiences. How do native and non-native English-speaking listeners perform on speech comprehension tasks under adverse acoustic conditions, if the English speech is produced by talkers of native English (Study 1) versus native Mandarin Chinese (Study 2)? Speech comprehension materials were played back in a listening chamber to individual listeners: native and non-native English-speaking in Study 1; native English, native Mandarin Chinese, and other non-native English-speaking in Study 2. Each listener was screened for baseline English proficiency level, and completed dual tasks simultaneously involving speech comprehension and adaptive dot-tracing under 15 acoustic conditions, comprised of three BNL conditions (RC-30, 40, and 50) and five RT scenarios (0.4 to 1.2 seconds). The results show that BNL and RT negatively affect both objective performance and subjective perception of speech comprehension, more severely for non

  14. Acoustic results of supersonic tip speed fan blade modification

    NASA Technical Reports Server (NTRS)

    Jutras, R. R.; Kazin, S. B.

    1974-01-01

    A supersonic tip speed single stage fan was modified with the intent of reducing multiple pure tone (MPT) or buzz saw noise. There were three modifications to the blades from the original design. The modifications to the blade resulted in an increase in cascade throat area causing the shock to start at a lower corrected fan speed. The acoustic results without acoustically absorbing liners showed substantial reduction in multiple pure tone levels. However, an increase in the blade passing frequency noise at takeoff fan speed accompanied the MPT reduction. The net result however, was a reduction in the maximum 1000-foot (304.8 m) altitude level flyover PNL. For the case with acoustic treatment in the inlet outer wall, the takeoff noise increased relative to an acoustically treated baseline. This was largely due to the increased blade passing frequency noise which was not effectively reduced by the liner.

  15. Acoustic actuation of bioinspired microswimmers.

    PubMed

    Kaynak, Murat; Ozcelik, Adem; Nourhani, Amir; Lammert, Paul E; Crespi, Vincent H; Huang, Tony Jun

    2017-01-31

    Acoustic actuation of bioinspired microswimmers is experimentally demonstrated. Microswimmers are fabricated in situ in a microchannel. Upon acoustic excitation, the flagellum of the microswimmer oscillates, which in turn generates linear or rotary movement depending on the swimmer design. The speed of these bioinspired microswimmers is tuned by adjusting the voltage amplitude applied to the acoustic transducer. Simple microfabrication and remote actuation are promising for biomedical applications.

  16. Design of Sequentially Randomized Trials for Testing Adaptive Treatment Strategies

    PubMed Central

    Ogbagaber, Semhar B.; Karp, Jordan; Wahed, Abdus S.

    2016-01-01

    An adaptive treatment strategy (ATS) is an outcome-guided algorithm that allows personalized treatment of complex diseases based on patients’ disease status and treatment history. Conditions such as AIDS, depression, and cancer usually require several stages of treatment due to the chronic, multifactorial nature of illness progression and management. Sequential multiple assignment randomized (SMAR) designs permit simultaneous inference about multiple ATSs, where patients are sequentially randomized to treatments at different stages depending upon response status. The purpose of the article is to develop a sample size formula to ensure adequate power for comparing two or more ATSs. Based on a Wald-type statistic for comparing multiple ATSs with a continuous endpoint, we develop a sample size formula and test it through simulation studies. We show via simulation that the proposed sample size formula maintains the nominal power. The proposed sample size formula is not applicable to designs with time-to-event endpoints but the formula will be useful for practitioners while designing SMAR trials to compare adaptive treatment strategies. PMID:26412033

  17. Yannawa wastewater treatment plant (Bangkok, Thailand): design, construction and operation.

    PubMed

    Kirkwood, S

    2004-01-01

    Yannawa Wastewater Treatment plant (Phase 1) serves a population equivalent of 500,000 and is located on a restricted site within the city of Bangkok, Thailand. Secondary treatment is based on the CASS sequencing batch reactor (SBR) process and the plant is one of the largest multi-storey SBRs in the world. The limitation of available site area, the ground conditions and the characteristics of the wastewater to be treated set a series of challenges for the designers, contractors and commissioning and operational staff. This paper briefly describes the collection system, the process selection and the treatment streams of the wastewater treatment plant. The SBR secondary treatment plant is described in more detail. The problems that arose during commissioning and operation and the solutions made possible by the use of an SBR type of process are discussed. Details of plant performance during performance testing and during the first three years of plant operation are provided.

  18. Education in acoustics in Argentina

    NASA Astrophysics Data System (ADS)

    Miyara, Federico

    2002-11-01

    Over the last decades, education in acoustics (EA) in Argentina has experienced ups and downs due to economic and political issues interfering with long term projects. Unlike other countries, like Chile, where EA has reached maturity in spite of the acoustical industry having shown little development, Argentina has several well-established manufacturers of acoustic materials and equipment but no specific career with a major in acoustics. At the university level, acoustics is taught as a complementary--often elective--course for careers such as architecture, communication engineering, or music. In spite of this there are several research centers with programs covering environmental and community noise, effects of noise on man, acoustic signal processing, musical acoustics and acoustic emission, and several national and international meetings are held each year in which results are communicated and discussed. Several books on a variety of topics such as sound system, architectural acoustics, and noise control have been published as well. Another chapter in EA is technical and vocational education, ranging between secondary and postsecondary levels, with technical training on sound system operation or design. Over the last years there have been several attempts to implement master degrees in acoustics or audio engineering, with little or no success.

  19. Creating Library Interiors: Planning and Design Considerations.

    ERIC Educational Resources Information Center

    Jones, Plummer Alston, Jr.; Barton, Phillip K.

    1997-01-01

    Examines design considerations for public library interiors: access; acoustical treatment; assignable and nonassignable space; building interiors: ceilings, clocks, color, control, drinking fountains; exhibit space: slotwall display, floor coverings, floor loading, furniture, lighting, mechanical systems, public address, copying machines,…

  20. Optimization of real-time acoustical and mechanical monitoring of high intensity focused ultrasound (HIFU) treatment using harmonic motion imaging for high focused ultrasound (HMIFU).

    PubMed

    Hou, Gary Y; Marquet, Fabrice; Wang, Shutao; Konofagou, Elisa E

    2013-01-01

    Harmonic Motion Imaging (HMI) for Focused Ultrasound (HMIFU) is a recently developed high-intensity focused ultrasound (HIFU) treatment monitoring method with feasibilities demonstrated in silica, in vitro and in vivo. Its principle is based on emission of an Amplitude-modulated therapeutic ultrasound beam utilizing a therapeutic transducer to induce an oscillatory radiation force while tracking the focal tissue mechanical response during the HIFU treatment using a confocally-aligned diagnostic transducer. In order to translate towards the clinical implementation of HMIFU, a complete assessment study is required in order to investigate the optimal radiation force threshold for reliable monitoring the local tissue mechanical property changes, i.e., the estimation HMIFU displacement under thermal, acoustical, and mechanical effects within focal medium (i.e., boiling, cavitation, and nonlinearity) using biological specimen. In this study, HMIFU technique is applied on HIFU treatment monitoring on freshly excised ex vivo canine liver specimens. In order to perform the multi-characteristic assessment, the diagnostic transducer was operated as either a pulse-echo imager or Passive Cavitation Detector (PCD) to assess the acoustic and mechanical response, while a bare-wire thermocouple was used to monitor the focal temperature change. As the acoustic power of HIFU treatment was ranged from 2.3 to 11.4 W, robust HMI displacement was observed across the entire range. Moreover, an optimized range for high quality displacement monitoring was found to be between 3.6 to 5.2W, where displacement showed an increase followed by significant decrease, indicating a stiffening of focal medium due to thermal lesion formation, while the correlation coefficient was maintained above 0.95.

  1. Zebra mussel control using acoustic energy

    SciTech Connect

    Tiller, G.W.; Gaucher, T.A.; Menezes, J.K.; Dolat, S.W. )

    1992-01-01

    A practical and economical device or method that reduces zebra mussel colonization without detrimental side effects is highly desirable. An ideal method is one that could be installed near, on, or in existing raw water intakes and conduits. It must have a known effect that is limited to a defined area, should have maximum effects on a targeted species, and preferably have a low life cycle cost than the current alternative methods of control and maintenance. Underwater sound could be such a desirable solution, if found to be an effective control measure for zebra mussels. Although sound most often applies specifically to acoustic energy that is audible to humans, 20 Hertz (Hz) to 20 kiloHertz (kHz), in this report we will use the terms sound and acoustic to include acoustic energy between 100 Hz and 100 MegaHertz (MHz). This research on zebra mussel biofouling is designed to effect the early developmental stages in the life cycle of Dreissena polymorpha (Pallas). Vulnerable stages in the development of D. polymorpha that might yield to site-specific acoustic deterrence measures include the free-swimming larval veliger stage, the postveliger pre-attachment demersal stage, and the immediate post-attachment stage. The proposed applications include surface treatment to prevent, reduce or eliminate colonization on underwater structures, and the stream treatment to reduce or eliminate (destroy) mussel larvae entrained in a moving volume of water.

  2. Process Design Manual: Wastewater Treatment Facilities for Sewered Small Communities.

    ERIC Educational Resources Information Center

    Leffel, R. E.; And Others

    This manual attempts to describe new treatment methods, and discuss the application of new techniques for more effectively removing a broad spectrum of contaminants from wastewater. Topics covered include: fundamental design considerations, flow equalization, headworks components, clarification of raw wastewater, activated sludge, package plants,…

  3. Effects of charge design features on parameters of acoustic and seismic waves and cratering, for SMR chemical surface explosions

    NASA Astrophysics Data System (ADS)

    Gitterman, Y.

    2012-04-01

    time delays clearly separated for the shot of IMI explosives (characterized by much higher detonation velocity than ANFO). Additionally acoustic records at close distances from WSMR explosions Distant Image (2440 tons of ANFO) and Minor Uncle (2725 tons of ANFO) were used to extend the charge and distance range for the SS delay scaled relationship, that showed consistency with SMR ANFO shots. The developed specific charge design contributed to the success of this unique dual Sayarim explosion experiment, providing the strongest GT0 sources since the establishment of the IMS network, that demonstrated clearly the most favorable westward/ eastward infrasound propagation up to 3400/6250 km according to appropriate summer/winter weather pattern and stratospheric wind directions, respectively, and thus verified empirically common models of infrasound propagation in the atmosphere. The research was supported by the CTBTO, Vienna, and the Israel Ministry of Immigrant Absorption.

  4. Modeling and design of two-dimensional membrane-type active acoustic metamaterials with tunable anisotropic density.

    PubMed

    Allam, Ahmed; Elsabbagh, Adel; Akl, Wael

    2016-11-01

    A two-dimensional active acoustic metamaterial with controllable anisotropic density is introduced. The material consists of composite lead-lead zirconate titanate plates clamped to an aluminum structure with air as the background fluid. The effective anisotropic density of the material is controlled, independently for two orthogonal directions, by means of an external static electric voltage signal. The material is used in the construction of a reconfigurable waveguide capable of controlling the direction of the acoustic waves propagating through it. An analytic model based on the acoustic two-port theory, the theory of piezoelectricity, the laminated pre-stressed plate theory, and the S-parameters retrieval method is developed to predict the behavior of the material. The results are verified using the finite element method. Excellent agreement is found between both models for the studied frequency and voltage ranges. The results show that, below 1600 Hz, the density is controllable within orders of magnitude relative to the uncontrolled case. The results also suggest that simple controllers could be used to program the material density toward full control of the directivity and dispersion characteristics of acoustic waves.

  5. The multipath propagation effect in gunshot acoustics and its impact on the design of sniper positioning systems

    NASA Astrophysics Data System (ADS)

    Ramos, António L. L.; Holm, Sverre; Gudvangen, Sigmund; Otterlei, Ragnvald

    2013-06-01

    Counter sniper systems rely on the detection and parameter estimation of the shockwave and the muzzle blast in order to determine the sniper location. In real-world situations, these acoustical signals can be disturbed by natural phenomena like weather and climate conditions, multipath propagation effect, and background noise. While some of these issues have received some attention in recent publications with application to gunshot acoustics, the multipath propagation phenomenon whose effect can not be neglected, specially in urban environments, has not yet been discussed in details in the technical literature in the same context. Propagating sound waves can be reflected at the boundaries in the vicinity of sound sources or receivers, whenever there is a difference in acoustical impedance between the reflective material and the air. Therefore, the received signal can be composed of a direct-path signal plus N scaled delayed copies of that signal. This paper presents a discussion on the multipath propagation effect and its impact on the performance and reliability of sniper positioning systems. In our formulation, propagation models for both the shockwave and the muzzle blast are considered and analyzed. Conclusions following the theoretical analysis of the problem are fully supported by actual gunshots acoustical signatures.

  6. 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.

  7. Sound Advice on Classroom Acoustics.

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2003-01-01

    Discusses the importance of acoustic standards in classroom design, presenting an interview with the Acoustical Society of America's (ASA's) standards manager which focuses on reasons for the new ASA standards, the standards document (which was written for K-12 classroom but applies to college classrooms), the need to avoid echo and be able to…

  8. Design and Fabrication of a Wide-Aperture HIFU Annular Array Transducer for the Treatment of Deep-Seated Tumors

    NASA Astrophysics Data System (ADS)

    Chen, Gin-Shin; Chang, Hsu; Kuo, Yi-Yuan; Lin, Winli; Chen, Wen-Shiang; Tseng, Wen-Yih

    2011-09-01

    In HIFU treatment applications, the annular array transducer is a feasible solution for the clinical/engineering requirements which are as follows: ablation of tumors deep inside body, electronic dynamic focusing in the depth direction, simple configuration/operation, and lower cost due to fewer elements/channels of amplifier. A 12 cm-diameter, 12 cm-radius-of-curvature annular array transducer has been developed in this study. The pseudo-inverse method was adopted to calculate the desired phase of each element for focusing, and the Rayleigh-Summerfield integral was used to obtain the ultrasonic pressure field. In the simulation, the operating frequency was 0.9 MHz, and the acoustic medium was water. A piece of 1-3 piezocomposite was fabricated using the dice and fill technique for the pilot test. The dimension of the sample was 4×2 cm, and it was thermally shaped using a spherical mold of 12 cm in radius. The results of the simulation showed that the focus could not be moved electronically in the depth direction until the number of elements (annuli) was equal to or higher than 5, and the dynamic focusing range increased as the number of elements increased. The intensity at the acoustic window or skin was also estimated from the simulated results and was only 0.03% of the intensity at focus. The curved composite sample was tested using an impedance analyser and a radiation force balance. The resonant frequency and electro-acoustic efficiency were measured to be 0.914 MHz and 65%, respectively. The results of the simulation can provide a design guideline for the development of different-size HIFU annular array transducers. A prototype of the HIFU annular array transducer designed is being fabricated in-house.

  9. Impact of insurance status and race on receipt of treatment for acoustic neuroma: A national cancer database analysis.

    PubMed

    McClelland, Shearwood; Kim, Ellen; Murphy, James D; Jaboin, Jerry J

    2017-03-23

    Acoustic neuroma (AN) management involves surgery, radiation, or observation. Previous studies have demonstrated that patient race and insurance status impact in-hospital morbidity/mortality following surgery; however the nationwide impact of these demographics on the receipt of each treatment modality has not been examined. The National Cancer Data Base (NCDB) from 2004 to 2013 identified AN patients. Multivariate analysis adjusted for several variables within each treatment modality, including patient age, race, sex, income, primary payer for care, tumor size, and medical comorbidities. Patients who were African-American (OR=0.7; 95%CI=0.5-0.9; p=0.01), elderly (minimum age 65) (OR=0.4; 95%CI=0.4-0.6; p<0.0001), on Medicare (OR=0.6; 95% CI=0.4-0.7; p=0.0005), or treated at a community hospital (OR=0.4; 95%CI=0.2-0.7; p=0.007) were less likely to receive surgery. Patients on Medicaid (OR=1.2; 95%CI=0.8-1.8; p=0.04) or treated at an integrated network (OR=1.2; 95%CI=0.9-1.6; p=0.0004) were more likely to receive surgery. Patients who were elderly (OR=2.2; 95%CI=1.7-2.9; p<0.0001) or treated in a comprehensive cancer center (OR=1.5; 95%CI=1.3-1.9; p=0.02) were more likely and Medicaid patients (OR=0.8; 95%CI=0.5-1.2; p=0.04) were less likely to receive radiation. Patients who were elderly (OR=2.2; 95%CI=1.7-2.7; p<0.0001), African-American (OR=1.5; 95%CI=1.1-2.0; p=0.01), on Medicare (OR=1.8; 95%CI=1.4-2.3; p=0.0003), or treated in a community hospital (OR=3.0; 95%CI=1.6-5.6; p=0.0007) were more likely to receive observation. Patients on Medicaid (OR=0.8; 95%CI=0.5-1.2; p=0.04) or treated in an integrated network (OR=0.8; 95%CI=0.6-1.0; p=0.0001) were less likely to receive observation. African-American race, elderly age, and community hospital treatment triaged towards observation/away from surgery; age also triaged towards radiation. Conversely, integrated networks triaged towards surgery/away from observation; comprehensive cancer centers triaged towards

  10. Design of Treatment Trials for Functional Gastrointestinal Disorders.

    PubMed

    Irvine, E Jan; Tack, Jan; Crowell, Michael D; Gwee, Kok Ann; Ke, Meiyun; Schmulson, Max J; Whitehead, William E; Spiegel, Brennan

    2016-05-01

    This article summarizes recent progress and regulatory guidance on design of trials to assess the efficacy of new therapies for functional gastrointestinal disorders (FGIDs). The double-masked, placebo-controlled, parallel-group design remains the accepted standard for evaluating treatment efficacy. A control group is essential, and a detailed description of the randomization process and concealed allocation method must be included in the study report. The control will most often be placebo, but for therapeutic procedures and for behavioral treatment trials, respectively, a sham procedure and control intervention with similar expectation of benefit, but lacking the treatment principle, are recommended. Investigators should be aware of, and attempt to minimize, expectancy effects (placebo, nocebo, precebo). The primary analysis should be based on the proportion of patients in each treatment arm who satisfy a treatment responder definition or a prespecified clinically meaningful change in a patient-reported outcome measure. Data analysis should use the intention-to-treat principle. Reporting of results should follow the Consolidated Standards for Reporting Trials guidelines and include secondary outcome measures to support or explain the primary outcome and an analysis of harms data. Trials should be registered in a public location before initiation and results should be published regardless of outcome.

  11. A Cabled Acoustic Telemetry System for Detecting and Tracking Juvenile Salmon: Part 1. Engineering Design and Instrumentation

    PubMed Central

    Weiland, Mark A.; Deng, Z. Daniel; Seim, Tom A.; LaMarche, Brian L.; Choi, Eric Y.; Fu, Tao; Carlson, Thomas J.; Thronas, Aaron I.; Eppard, M. Brad

    2011-01-01

    In 2001 the U.S. Army Corps of Engineers, Portland District (OR, USA), started developing the Juvenile Salmon Acoustic Telemetry System, a nonproprietary sensing technology, to meet the needs for monitoring the survival of juvenile salmonids through eight large hydroelectric facilities within the Federal Columbia River Power System (FCRPS). Initial development focused on coded acoustic microtransmitters and autonomous receivers that could be deployed in open reaches of the river for detection of the juvenile salmonids implanted with microtransmitters as they passed the autonomous receiver arrays. In 2006, the Pacific Northwest National Laboratory began the development of an acoustic receiver system for deployment at hydropower facilities (cabled receiver) for detecting fish tagged with microtransmitters as well as tracking them in two or three dimensions for determining route of passage and behavior as the fish passed at the facility. The additional information on route of passage, combined with survival estimates, is used by the dam operators and managers to make structural and operational changes at the hydropower facilities to improve survival of fish as they pass the facilities through the FCRPS. PMID:22163918

  12. A cabled acoustic telemetry system for detecting and tracking juvenile salmon: Part 1. Engineering design and instrumentation

    SciTech Connect

    Weiland, Mark A.; Deng, Zhiqun; Seim, Thomas A.; Lamarche, Brian L.; Choi, Eric Y.; Fu, Tao; Carlson, Thomas J.; Thronas, Aaron I.; Eppard, Matthew B.

    2011-05-26

    The U.S. Army Corps of Engineers-Portland District started development of the Juvenile Salmon Acoustic Telemetry System (JSATS), a nonproprietary technology, in 2001 to meet the needs for monitoring the survival of juvenile salmonids through the 31 federal dams in the Federal Columbia River Power System (FCRPS). Initial development focused on coded acoustic microtransmitters, and autonomous receivers that could be deployed in open reaches of the river for detection of the juvenile salmonids implanted with microtransmitters as they passed the autonomous receiver arrays. In 2006 the Pacific Northwest National Laboratory (PNNL) was tasked with development of an acoustic receiver system for deployment at hydropower facilities (cabled receiver) for detecting fish tagged with microtransmitters as well as tracking them in 2 or 3-dimensions as the fish passed at the facility for determining route of passage. The additional route of passage information, combined with survival estimates, is used by the dam operators and managers to make structural and operational changes at the hydropower facilities to improve survival of fish as they pass the facilities and through the FCRPS.

  13. A cabled acoustic telemetry system for detecting and tracking juvenile salmon: part 1. Engineering design and instrumentation.

    PubMed

    Weiland, Mark A; Deng, Z Daniel; Seim, Tom A; LaMarche, Brian L; Choi, Eric Y; Fu, Tao; Carlson, Thomas J; Thronas, Aaron I; Eppard, M Brad

    2011-01-01

    In 2001 the U.S. Army Corps of Engineers, Portland District (OR, USA), started developing the Juvenile Salmon Acoustic Telemetry System, a nonproprietary sensing technology, to meet the needs for monitoring the survival of juvenile salmonids through eight large hydroelectric facilities within the Federal Columbia River Power System (FCRPS). Initial development focused on coded acoustic microtransmitters and autonomous receivers that could be deployed in open reaches of the river for detection of the juvenile salmonids implanted with microtransmitters as they passed the autonomous receiver arrays. In 2006, the Pacific Northwest National Laboratory began the development of an acoustic receiver system for deployment at hydropower facilities (cabled receiver) for detecting fish tagged with microtransmitters as well as tracking them in two or three dimensions for determining route of passage and behavior as the fish passed at the facility. The additional information on route of passage, combined with survival estimates, is used by the dam operators and managers to make structural and operational changes at the hydropower facilities to improve survival of fish as they pass the facilities through the FCRPS.

  14. Intelligent Engine Systems: Acoustics

    NASA Technical Reports Server (NTRS)

    Wojno, John; Martens, Steve; Simpson, Benjamin

    2008-01-01

    An extensive study of new fan exhaust nozzle technologies was performed. Three new uniform chevron nozzles were designed, based on extensive CFD analysis. Two new azimuthally varying variants were defined. All five were tested, along with two existing nozzles, on a representative model-scale, medium BPR exhaust nozzle. Substantial acoustic benefits were obtained from the uniform chevron nozzle designs, the best benefit being provided by an existing design. However, one of the azimuthally varying nozzle designs exhibited even better performance than any of the uniform chevron nozzles. In addition to the fan chevron nozzles, a new technology was demonstrated, using devices that enhance mixing when applied to an exhaust nozzle. The acoustic benefits from these devices applied to medium BPR nozzles were similar, and in some cases superior to, those obtained from conventional uniform chevron nozzles. However, none of the low noise technologies provided equivalent acoustic benefits on a model-scale high BPR exhaust nozzle, similar to current large commercial applications. New technologies must be identified to improve the acoustics of state-of-the-art high BPR jet engines.

  15. 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.

  16. Design of compact electromagnetic impulse radiating antenna for melanoma treatment.

    PubMed

    Arockiasamy, Petrishia; Mohan, Sasikala

    2016-01-01

    Cancer therapy is one of the several new applications which use nanosecond and subnanosecond high voltage pulses. New treatment based on electromagnetic (EM) fields have been developed as non-surgical and minimally invasive treatments of tumors. In particular, subnanosecond pulses can introduce important non-thermal changes in cell biology, especially the permeabilization of the cell membrane. The motivation behind this work is to launch intense subnanosecond pulses to the target (tumors) non-invasively. This works focuses on the design of a compact intense pulsed EM radiating antenna. In tense EM waves radiated at the first focal point of the Prolate Spheroidal Reflector (PSR) are focused at the second focal point where the target (tumor) is present. Two antennas with PSR but fed with different compact wave radiator are designed to focus pulsed field at the second focal point. The PSR with modified bicone antenna feed and PSR with elliptically tapered horn antenna feed are designed. The design parameters and radiation performance are discussed.

  17. Biomaterial Design Strategies for the Treatment of Spinal Cord Injuries

    PubMed Central

    Straley, Karin S.; Po Foo, Cheryl Wong

    2010-01-01

    Abstract The highly debilitating nature of spinal cord injuries has provided much inspiration for the design of novel biomaterials that can stimulate cellular regeneration and functional recovery. Many experts agree that the greatest hope for treatment of spinal cord injuries will involve a combinatorial approach that integrates biomaterial scaffolds, cell transplantation, and molecule delivery. This manuscript presents a comprehensive review of biomaterial-scaffold design strategies currently being applied to the development of nerve guidance channels and hydrogels that more effectively stimulate spinal cord tissue regeneration. To enhance the regenerative capacity of these two scaffold types, researchers are focusing on optimizing the mechanical properties, cell-adhesivity, biodegradability, electrical activity, and topography of synthetic and natural materials, and are developing mechanisms to use these scaffolds to deliver cells and biomolecules. Developing scaffolds that address several of these key design parameters will lead to more successful therapies for the regeneration of spinal cord tissue. PMID:19698073

  18. Method of Adjusting Acoustic Impedances for Impedance-Tunable Acoustic Segments

    NASA Technical Reports Server (NTRS)

    Jones, Kennie H (Inventor); Nark, Douglas M. (Inventor); Jones, Michael G. (Inventor); Parrott, Tony L. (Inventor); Lodding, Kenneth N. (Inventor)

    2012-01-01

    A method is provided for making localized decisions and taking localized actions to achieve a global solution. In an embodiment of the present invention, acoustic impedances for impedance-tunable acoustic segments are adjusted. A first acoustic segment through an N-th acoustic segment are defined. To start the process, the first acoustic segment is designated as a leader and a noise-reducing impedance is determined therefor. This is accomplished using (i) one or more metrics associated with the acoustic wave at the leader, and (ii) the metric(s) associated with the acoustic wave at the N-th acoustic segment. The leader, the N-th acoustic segment, and each of the acoustic segments exclusive of the leader and the N-th acoustic segment, are tuned to the noise-reducing impedance. The current leader is then excluded from subsequent processing steps. The designation of leader is then given one of the remaining acoustic segments, and the process is repeated for each of the acoustic segments through an (N-1)-th one of the acoustic segments.

  19. Measuring acoustic habitats.

    PubMed

    Merchant, Nathan D; Fristrup, Kurt M; Johnson, Mark P; Tyack, Peter L; Witt, Matthew J; Blondel, Philippe; Parks, Susan E

    2015-03-01

    1. Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. 2. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. 3. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies.

  20. Measuring acoustic habitats

    PubMed Central

    Merchant, Nathan D; Fristrup, Kurt M; Johnson, Mark P; Tyack, Peter L; Witt, Matthew J; Blondel, Philippe; Parks, Susan E

    2015-01-01

    1. Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. 2. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. 3. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies. PMID:25954500

  1. Broadband Acoustic Hyperbolic Metamaterial.

    PubMed

    Shen, Chen; Xie, Yangbo; Sui, Ni; Wang, Wenqi; Cummer, Steven A; Jing, Yun

    2015-12-18

    In this Letter, we report on the design and experimental characterization of a broadband acoustic hyperbolic metamaterial. The proposed metamaterial consists of multiple arrays of clamped thin plates facing the y direction and is shown to yield opposite signs of effective density in the x and y directions below a certain cutoff frequency, therefore, yielding a hyperbolic dispersion. Partial focusing and subwavelength imaging are experimentally demonstrated at frequencies between 1.0 and 2.5 kHz. The proposed metamaterial could open up new possibilities for acoustic wave manipulation and may find usage in medical imaging and nondestructive testing.

  2. Acoustic tooth cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S. (Inventor)

    1982-01-01

    An acoustic oral hygiene unit is described that uses acoustic energy to oscillate mild abrasive particles in a water suspension which is then directed in a low pressure stream onto the teeth. The oscillating abrasives scrub the teeth clean removing food particles, plaque, calculous, and other foreign material from tooth surfaces, interproximal areas, and tooth-gingiva interface more effectively than any previous technique. The relatively low power output and the basic design makes the invention safe and convenient for everyday use in the home without special training. This invention replaces all former means of home dental prophylaxis, and requires no augmentation to fulfill all requirements for daily oral hygienic care.

  3. Introducing passive acoustic filter in acoustic based condition monitoring: Motor bike piston-bore fault identification

    NASA Astrophysics Data System (ADS)

    Jena, D. P.; Panigrahi, S. N.

    2016-03-01

    Requirement of designing a sophisticated digital band-pass filter in acoustic based condition monitoring has been eliminated by introducing a passive acoustic filter in the present work. So far, no one has attempted to explore the possibility of implementing passive acoustic filters in acoustic based condition monitoring as a pre-conditioner. In order to enhance the acoustic based condition monitoring, a passive acoustic band-pass filter has been designed and deployed. Towards achieving an efficient band-pass acoustic filter, a generalized design methodology has been proposed to design and optimize the desired acoustic filter using multiple filter components in series. An appropriate objective function has been identified for genetic algorithm (GA) based optimization technique with multiple design constraints. In addition, the sturdiness of the proposed method has been demonstrated in designing a band-pass filter by using an n-branch Quincke tube, a high pass filter and multiple Helmholtz resonators. The performance of the designed acoustic band-pass filter has been shown by investigating the piston-bore defect of a motor-bike using engine noise signature. On the introducing a passive acoustic filter in acoustic based condition monitoring reveals the enhancement in machine learning based fault identification practice significantly. This is also a first attempt of its own kind.

  4. Effect Size for Single-Subject Design in Phonological Treatment

    PubMed Central

    Morrisette, Michele L.; Dickinson, Stephanie L.

    2015-01-01

    Purpose The purpose of this study was to document, validate, and corroborate effect size (ES) for single-subject design in treatment of children with functional phonological disorders; to evaluate potential child-specific contributing variables relative to ES; and to establish benchmarks for interpretation of ES for the population. Method Data were extracted from the Developmental Phonologies Archive for 135 preschool children with phonological disorders who previously participated in single-subject experimental treatment studies. Standard mean differenceall with correction for continuity was computed to gauge the magnitude of generalization gain that accrued longitudinally from treatment for each child with the data aggregated for purposes of statistical analyses. Results ES ranged from 0.09 to 27.83 for the study population. ES was positively correlated with conventional measures of phonological learning and visual inspection of learning data on the basis of procedures standard to single-subject design. ES was linked to children's performance on diagnostic assessments of phonology but not other demographic characteristics or related linguistic skills and nonlinguistic skills. Benchmarks for interpretation of ES were estimated as 1.4, 3.6, and 10.1 for small, medium, and large learning effects, respectively. Conclusion Findings have utility for single-subject research and translation of research to evidence-based practice for children with phonological disorders. PMID:26184118

  5. Shape optimization: Good looks and acoustics too!

    NASA Astrophysics Data System (ADS)

    D'Antonio, Peter; Cox, Trevor J.; Haas, Steve

    2003-04-01

    One of the challenges in the architectural acoustic design of museums and other public spaces is to develop contemporary scattering surfaces that complement contemporary architecture in the way that statuary, coffered ceilings, columns, and relief ornamentation complemented classic architecture. Often acoustic surfaces satisfy the acoustics, but may or may not satisfy the aesthetics. One approach that has been successful employs a combination of boundary element and multidimensional optimization techniques. The architect supplies the desired shape motif and the acoustician supplies the acoustical performance requirements. The optimization program then provides an Arcousthetic surface, which simultaneously satisfies the architecture, the acoustics, and the aesthetics. The program can be used with diffusive or diffsorptive surfaces. Photos of installations using these acoustic tools and a description of the design of the National Museum of the American Indian will also be presented to illustrate the usefulness of these devices and their impact on architectural acoustics.

  6. Design and Research of the Sewage Treatment Control System

    NASA Astrophysics Data System (ADS)

    Chu, J.; Hu, W. W.

    Due to the rapid development of China's economy, the water pollution has become a problem that we have to face. In particular, how to deal with industrial wastewater has become a top priority. In wastewater treatment, the control system based on PLC has met the design requirement in real-time, reliability, precision and so on. The integration of sequence control and process control in PLC, has the characteristics of high reliability, simple network, convenient and flexible use. PLC is a powerful tool for small and medium-sized industrial automation. Therefore, the sewage treatment control system take PLC as the core of control system, can nicely solve the problem of industrial wastewater in a certain extent.

  7. Design of sidewall treatment of cabin noise control of a twin engine turboprop aircraft

    NASA Technical Reports Server (NTRS)

    Vaicaitis, R.; Slazak, M.

    1983-01-01

    An analytical procedure was used to predict the noise transmission into the cabin of a twin engine general aviation aircraft. This model was then used to optimize the interior A weighted noise levels to an average value of about 85 dBA. The surface pressure noise spectral levels were selected utilizing experimental flight data and empirical predictions. The add on treatments considered in this optimization study include aluminum honeycomb panels, constrained layer damping tape, porous acoustic blankets, acoustic foams, septum barriers and limp trim panels which are isolated from the vibration of the main sidewall structure. To reduce the average noise level in the cabin from about 102 kBA (baseline) to 85 dBA (optimized), the added weight of the noise control treatment is about 2% of the total gross takeoff weight of the aircraft.

  8. 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

  9. 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.

  10. 9- by 15-Foot Low Speed Wind Tunnel Acoustic Improvements Expanded Overview

    NASA Technical Reports Server (NTRS)

    Stephens, David

    2016-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) at NASA Glenn Research Center was built in 1969 in the return leg of the 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT). The 8x6 SWT was completed in 1949 and acoustically treated to mitigate community noise issues in 1950. This treatment included the addition of a large muffler downstream of the 8x6 SWT test section and diffuser. The 9x15 LSWT was designed for performance testing of V/STOL aircraft models, but with the addition of the current acoustic treatment in 1986 the tunnel been used principally for acoustic and performance testing of aircraft propulsion systems. The present document describes an anticipated acoustic upgrade to be completed in 2017.

  11. Radiation dose to the tongue and velopharynx predicts acoustic-articulatory changes after chemo-IMRT treatment for advanced head and neck cancer.

    PubMed

    Jacobi, Irene; Navran, Arash; van der Molen, Lisette; Heemsbergen, Wilma D; Hilgers, Frans J M; van den Brekel, Michiel W M

    2016-02-01

    The aim of this study was to investigate to what extent changes in speech after C-IMRT treatment are related to mean doses to the tongue and velopharynx (VP). In 34 patients with advanced hypopharyngeal, nasopharyngeal, or oropharyngeal cancer, changes in speech from pretreatment to 10 weeks and 1 year posttreatment were correlated with mean doses to the base of tongue (BOT), oral cavity (OC) and tonsillar fossa/soft palate (VP). Differences in anteroposterior tongue position, dorsoventral degree of tongue to palate or pharynx constriction, grooving, strength, nasality, and laryngeal rise, were assessed by acoustic changes in three speech sounds that depend on a (post-) alveolar closure or narrowing (/t/, /s/, /z/), three with a tongue to palate/pharyngeal narrowing (/l/, /r/, /u/), and in vowel /a/ at comfortable and highest pitch. Acoustically assessed changes in tongue positioning, shape, velopharyngeal constriction, and laryngeal elevation were significantly related to mean doses to the tongue and velopharynx. The mean dose to BOT predicted changes in anteroposterior tongue positioning from pre- to 10-weeks posttreatment. From pretreatment to 1-year, mean doses to BOT, OC, and VP were related to changes in grooving, strength, laryngeal height, nasality, palatalization, and degree of pharyngeal constriction. Changes in speech are related to mean doses to the base of tongue and velopharynx. The outcome indicates that strength, motility, and the balance between agonist and antagonist muscle forces change significantly after radiotherapy.

  12. Nanotechnology-based intelligent drug design for cancer metastasis treatment.

    PubMed

    Gao, Yu; Xie, Jingjing; Chen, Haijun; Gu, Songen; Zhao, Rongli; Shao, Jingwei; Jia, Lee

    2014-01-01

    Traditional chemotherapy used today at clinics is mainly inherited from the thinking and designs made four decades ago when the Cancer War was declared. The potency of those chemotherapy drugs on in-vitro cancer cells is clearly demonstrated at even nanomolar levels. However, due to their non-specific effects in the body on normal tissues, these drugs cause toxicity, deteriorate patient's life quality, weaken the host immunosurveillance system, and result in an irreversible damage to human's own recovery power. Owing to their unique physical and biological properties, nanotechnology-based chemotherapies seem to have an ability to specifically and safely reach tumor foci with enhanced efficacy and low toxicity. Herein, we comprehensively examine the current nanotechnology-based pharmaceutical platforms and strategies for intelligent design of new nanomedicines based on targeted drug delivery system (TDDS) for cancer metastasis treatment, analyze the pros and cons of nanomedicines versus traditional chemotherapy, and evaluate the importance that nanomaterials can bring in to significantly improve cancer metastasis treatment.

  13. PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

    SciTech Connect

    John L. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Patrick Browning

    2004-07-20

    The Portable Acoustic Monitoring Package (PAMP) has been designed to record and monitor the acoustic signal in natural gas transmission lines. In particular the three acoustic signals associated with a line leak. The system is portable ({approx}30 lbs) and is designed for line pressures up to 1000 psi. It has become apparent that cataloging of the various background acoustic signals in natural gas transmission line is very important if a system to identify leak signals is to be developed. The low-pressure (0-200 psig) laboratory test phase has been completed and a number of field trials have been conducted. Before the cataloging phase could begin, a few problems identified in field trials identified had to be corrected such as: (1) Decreased microphone sensitivity at line pressures above 250 psig. (2) The inability to deal with large data sets collected when cataloging the variety of signals in a transmission line. (3) The lack of an available online acoustic calibration system. These problems have been solved and the WVU PAMP is now fully functional over the entire pressure range found in the Natural Gas transmission lines in this region. Field portability and reliability have been greatly improved. Data collection and storage have also improved to the point were the full acoustic spectrum of acoustic signals can be accurately cataloged, recorded and described.

  14. A Brief History of Acoustics

    NASA Astrophysics Data System (ADS)

    Rossing, Thomas D.

    Although there are certainly some good historical treatments of acoustics in the literature, it still seems appropriate to begin a handbook of history acoustics with a brief history of the subject. We begin by mentioning some important experiments that took place before the 19th century. Acoustics in the 19th century is characterized by describing the work of seven outstanding acousticians: Tyndall, von Helmholtz, Rayleigh, Stokes, Bell, Edison, and Koenig. Of course this sampling omits the mention of many other outstanding investigators.

  15. Evaluating many treatments and biomarkers in oncology: a new design.

    PubMed

    Kaplan, Richard; Maughan, Timothy; Crook, Angela; Fisher, David; Wilson, Richard; Brown, Louise; Parmar, Mahesh

    2013-12-20

    There is a pressing need for more-efficient trial designs for biomarker-stratified clinical trials. We suggest a new approach to trial design that links novel treatment evaluation with the concurrent evaluation of a biomarker within a confirmatory phase II/III trial setting. We describe a new protocol using this approach in advanced colorectal cancer called FOCUS4. The protocol will ultimately answer three research questions for a number of treatments and biomarkers: (1) After a period of first-line chemotherapy, do targeted novel therapies provide signals of activity in different biomarker-defined populations? (2) If so, do these definitively improve outcomes? (3) Is evidence of activity restricted to the biomarker-defined groups? The protocol randomizes novel agents against placebo concurrently across a number of different biomarker-defined population-enriched cohorts: BRAF mutation; activated AKT pathway: PI3K mutation/absolute PTEN loss tumors; KRAS and NRAS mutations; and wild type at all the mentioned genes. Within each biomarker-defined population, the trial uses a multistaged approach with flexibility to adapt in response to planned interim analyses for lack of activity. FOCUS4 is the first test of a protocol that assigns all patients with metastatic colorectal cancer to one of a number of parallel population-enriched, biomarker-stratified randomized trials. Using this approach allows questions regarding efficacy and safety of multiple novel therapies to be answered in a relatively quick and efficient manner, while also allowing for the assessment of biomarkers to help target treatment.

  16. Investigations of detail design issues for the high speed acoustic wind tunnel using a 60th scale model tunnel. Part 1: Tests with open circuits

    NASA Technical Reports Server (NTRS)

    Barna, P. Stephen

    1991-01-01

    This report summarizes the tests on the 1:60 scale model of the High Speed Acoustic Wind Tunnel (HSAWT) performed during the period of November 1989 to December 1990. Throughout the testing the tunnel was operated in the 'open circuit mode', that is when the airflow was induced by a powerful exhaust fan located outside the tunnel circuit. The tests were first performed with the closed test section and were subsequently repeated with the open test section. While operating with the open test section, a novel device, called the 'nozzle-diffuser,' was also tested in order to establish its usefulness of increasing pressure recovery in the first diffuser. The tests established the viability of the tunnel design. The flow distribution in each tunnel component was found acceptable and pressure recovery in the diffusers were found satisfactory. The diffusers appeared to operate without flow separation. All tests were performed at NASA LaRC.

  17. Fan Acoustic Issues in the NASA Space Flight Experience

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S.; Goodman, Jerry

    2008-01-01

    Emphasis needs to be placed on choosing quiet fans compatible with systems design and specifications that control spec levels: a) Sound power; b) Choose quiet fan or plan to quiet it, early in program; c) Plan early verification that fan source allocations are met. Airborne noise: a) System design should function/play together with fans used (flow passages, restrictions, bends, expansions & contractions, and acoustics) vs. fan speed understood (nominal, worst case, & unplanned variances); b) Fan inlets treated, as required; c) Fan Outlets treated, as required; d) Ducted system inlets are outlets designed for acoustic compliance compatibility & designed so some late required modifications can be made without significant impacts. Structure Borne Noise: a) Structure borne noise dealt with as part of fan package or installation; b) Duct attachments and lines isolated. Case Radiated Noise: - Treatment added as much as possible to fan package (see example).

  18. Analysis of binary mixtures of aqueous aromatic hydrocarbons with low-phase-noise shear-horizontal surface acoustic wave sensors using multielectrode transducer designs.

    PubMed

    Bender, Florian; Mohler, Rachel E; Ricco, Antonio J; Josse, Fabien

    2014-11-18

    The present work investigates a compact sensor system that provides rapid, real-time, in situ measurements of the identities and concentrations of aromatic hydrocarbons at parts-per-billion concentrations in water through the combined use of kinetic and thermodynamic response parameters. The system uses shear-horizontal surface acoustic wave (SH-SAW) sensors operating directly in the liquid phase. The 103 MHz SAW sensors are coated with thin sorbent polymer films to provide the appropriate limits of detection as well as partial selectivity for the analytes of interest, the BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), which are common indicators of fuel and oil accidental releases in groundwater. Particular emphasis is placed on benzene, a known carcinogen and the most challenging BTEX analyte with regard to both regulated levels and its solubility properties. To demonstrate the identification and quantification of individual compounds in multicomponent aqueous samples, responses to binary mixtures of benzene with toluene as well as ethylbenzene were characterized at concentrations below 1 ppm (1 mg/L). The use of both thermodynamic and kinetic (i.e., steady-state and transient) responses from a single polymer-coated SH-SAW sensor enabled identification and quantification of the two BTEX compounds in binary mixtures in aqueous solution. The signal-to-noise ratio was improved, resulting in lower limits of detection and improved identification at low concentrations, by designing and implementing a type of multielectrode transducer pattern, not previously reported for chemical sensor applications. The design significantly reduces signal distortion and root-mean-square (RMS) phase noise by minimizing acoustic wave reflections from electrode edges, thus enabling limits of detection for BTEX analytes of 9-83 ppb (calculated from RMS noise); concentrations of benzene in water as low as ~100 ppb were measured directly. Reliable quantification of BTEX

  19. Nonlinear Acoustics

    DTIC Science & Technology

    1974-02-14

    Wester- velt. [60] Streaming. In 1831, Michael Faraday [61] noted that currents of air were set up in the neighborhood of vibrating plates-the first... ducei in the case of a paramettc amy (from Berktay an Leahy 141). C’ "". k•, SEC 10.1 NONLINEAR ACOUSTICS 345 The principal results of their analysis

  20. Acoustic Multipurpose Cargo Transfer Bag

    NASA Technical Reports Server (NTRS)

    Baccus, Shelley

    2015-01-01

    The Logistics Reduction (LR) project within the Advanced Exploration Systems (AES) program is tasked with reducing logistical mass and repurposing logistical items. Multipurpose Cargo Transfer Bags (MCTB) are designed to be the same external volume as a regular cargo transfer bag, the common logistics carrier for the International Space Station. After use as a cargo bag, the MCTB can be unzipped and unfolded to be reused. This Acoustic MCTBs transform into acoustic blankets after the initial logistics carrying objective is complete.

  1. Acoustic techniques in nuclear safeguards

    SciTech Connect

    Olinger, C.T.; Sinha, D.N.

    1995-07-01

    Acoustic techniques can be employed to address many questions relevant to current nuclear technology needs. These include establishing and monitoring intrinsic tags and seals, locating holdup in areas where conventional radiation-based measurements have limited capability, process monitoring, monitoring containers for corrosion or changes in pressure, and facility design verification. These acoustics applications are in their infancy with respect to safeguards and nuclear material management, but proof-of-principle has been demonstrated in many of the areas listed.

  2. Acoustically-driven microfluidic systems

    SciTech Connect

    Wang, A W; Benett, W J; Tarte, L R

    2000-06-23

    We have demonstrated a non-contact method of concentrating and mixing particles in a plastic microfluidic chamber employing acoustic radiation pressure. A flaw cell package has also been designed that integrates liquid sample interconnects, electrical contacts and a removable sample chamber. Experiments were performed on 1, 3, 6, and 10 {micro}m polystyrene beads. Increased antibody binding to a solid-phase substrate was observed in the presence of acoustic mixing due to improve mass transport.

  3. Acoustic Transduction Materials and Devices

    DTIC Science & Technology

    1998-01-01

    are to Cymbal and Tonpilz transducer arrays for 3 - 50 kHz sonars, thin/thick film transducers for 10 - 100 MHz medical acoustic devices...Cymbal arrayed projectors, PMN Tonpilz tunable transducers , thin/thick film micro- Tonpilz transducers and controlling electronics. The Center for...emphasis is shifting to the acoustic vector sensor. Film transducers The goal is to use the tonpilz design to facilitate development of high

  4. Opto-acoustic cell permeation

    SciTech Connect

    Visuri, S R; Heredia, N

    2000-03-09

    Optically generated acoustic waves have been used to temporarily permeate biological cells. This technique may be useful for enhancing transfection of DNA into cells or enhancing the absorption of locally delivered drugs. A diode-pumped frequency-doubled Nd:YAG laser operating at kHz repetition rates was used to produce a series of acoustic pulses. An acoustic wave was formed via thermoelastic expansion by depositing laser radiation into an absorbing dye. Generated pressures were measured with a PVDF hydrophone. The acoustic waves were transmitted to cultured and plated cells. The cell media contained a selection of normally- impermeable fluorescent-labeled dextran dyes. Following treatment with the opto-acoustic technique, cellular incorporation of dyes, up to 40,000 Molecular Weight, was noted. Control cells that did not receive opto-acoustic treatment had unremarkable dye incorporation. Uptake of dye was quantified via fluorescent microscopic analysis. Trypan Blue membrane exclusion assays and fluorescent labeling assays confirmed the vitality of cells following treatment. This method of enhanced drug delivery has the potential to dramatically reduce required drug dosages and associated side effects and enable revolutionary therapies.

  5. Acoustic methodology review

    NASA Technical Reports Server (NTRS)

    Schlegel, R. G.

    1982-01-01

    It is important for industry and NASA to assess the status of acoustic design technology for predicting and controlling helicopter external noise in order for a meaningful research program to be formulated which will address this problem. The prediction methodologies available to the designer and the acoustic engineer are three-fold. First is what has been described as a first principle analysis. This analysis approach attempts to remove any empiricism from the analysis process and deals with a theoretical mechanism approach to predicting the noise. The second approach attempts to combine first principle methodology (when available) with empirical data to formulate source predictors which can be combined to predict vehicle levels. The third is an empirical analysis, which attempts to generalize measured trends into a vehicle noise prediction method. This paper will briefly address each.

  6. Micro acoustic spectrum analyzer

    DOEpatents

    Schubert, W. Kent; Butler, Michael A.; Adkins, Douglas R.; Anderson, Larry F.

    2004-11-23

    A micro acoustic spectrum analyzer for determining the frequency components of a fluctuating sound signal comprises a microphone to pick up the fluctuating sound signal and produce an alternating current electrical signal; at least one microfabricated resonator, each resonator having a different resonant frequency, that vibrate in response to the alternating current electrical signal; and at least one detector to detect the vibration of the microfabricated resonators. The micro acoustic spectrum analyzer can further comprise a mixer to mix a reference signal with the alternating current electrical signal from the microphone to shift the frequency spectrum to a frequency range that is a better matched to the resonant frequencies of the microfabricated resonators. The micro acoustic spectrum analyzer can be designed specifically for portability, size, cost, accuracy, speed, power requirements, and use in a harsh environment. The micro acoustic spectrum analyzer is particularly suited for applications where size, accessibility, and power requirements are limited, such as the monitoring of industrial equipment and processes, detection of security intrusions, or evaluation of military threats.

  7. 78 FR 11207 - Clinical Study Designs for Surgical Ablation Devices for Treatment of Atrial Fibrillation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-15

    ... Treatment of Atrial Fibrillation; Guidance for Industry and Food and Drug Administration Staff; Availability... Ablation Devices for Treatment of Atrial Fibrillation.'' This guidance provides FDA's recommendations on clinical trial designs for surgical ablation devices intended for the treatment of atrial...

  8. SLS Scale Model Acoustic Test Liftoff Results and Comparisons

    NASA Technical Reports Server (NTRS)

    Houston, Janice; Counter, Douglas; Giacomoni, Clothilde

    2015-01-01

    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible design phase test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments.

  9. Acoustic transistor: Amplification and switch of sound by sound

    NASA Astrophysics Data System (ADS)

    Liang, Bin; Kan, Wei-wei; Zou, Xin-ye; Yin, Lei-lei; Cheng, Jian-chun

    2014-08-01

    We designed an acoustic transistor to manipulate sound in a manner similar to the manipulation of electric current by its electrical counterpart. The acoustic transistor is a three-terminal device with the essential ability to use a small monochromatic acoustic signal to control a much larger output signal within a broad frequency range. The output and controlling signals have the same frequency, suggesting the possibility of cascading the structure to amplify an acoustic signal. Capable of amplifying and switching sound by sound, acoustic transistors have various potential applications and may open the way to the design of conceptual devices such as acoustic logic gates.

  10. Bacterial Temporal Dynamics Enable Optimal Design of Antibiotic Treatment

    PubMed Central

    Meredith, Hannah R.; Lopatkin, Allison J.; Anderson, Deverick J.; You, Lingchong

    2015-01-01

    There is a critical need to better use existing antibiotics due to the urgent threat of antibiotic resistant bacteria coupled with the reduced effort in developing new antibiotics. β-lactam antibiotics represent one of the most commonly used classes of antibiotics to treat a broad spectrum of Gram-positive and -negative bacterial pathogens. However, the rise of extended spectrum β-lactamase (ESBL) producing bacteria has limited the use of β-lactams. Due to the concern of complex drug responses, many β-lactams are typically ruled out if ESBL-producing pathogens are detected, even if these pathogens test as susceptible to some β-lactams. Using quantitative modeling, we show that β-lactams could still effectively treat pathogens producing low or moderate levels of ESBLs when administered properly. We further develop a metric to guide the design of a dosing protocol to optimize treatment efficiency for any antibiotic-pathogen combination. Ultimately, optimized dosing protocols could allow reintroduction of a repertoire of first-line antibiotics with improved treatment outcomes and preserve last-resort antibiotics. PMID:25905796

  11. 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.

  12. 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.

  13. Controlling sound with acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Cummer, Steven A.; Christensen, Johan; Alù, Andrea

    2016-03-01

    Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales. The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create effective material properties that are not possible with passive structures and have led to the development of dynamically reconfigurable, loss-compensating and parity-time-symmetric materials for sound manipulation. Challenges remain, including the development of efficient techniques for fabricating large-scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview of future directions in the field.

  14. Acoustic performance of two 1.83-meter-diameter fans designed for a wind-tunnel drive system

    NASA Technical Reports Server (NTRS)

    Soderman, P. R.; Page, V. R.

    1977-01-01

    A parametric study was made of the noise generated by two 1.83-m (6-ft) diameter fans operating up to a maximum pressure ratio of 1.03. One fan had 15 rotor blades, 23 stator blades, and a maximum rotational speed of 1200 rpm. The other fan had 9 rotor blades, 13 stator blades, and a maximum speed of 2,000 rpm. The fans were approximately 1/7-scale models of the 12.2-m (40-ft) diameter fans proposed for repowering the NASA-Ames 40- by 80 foot wind tunnel. The fans were operated individually in a 23.8-m (78-ft) long duct. Sound pressure levels in the duct were used to determine radiated acoustic power as fan speed, blade angle, and mass flow were varied. Results show that the low speed fan was slightly quieter than the high speed fan and, when scaled to full scale, would be 16 db quieter than the present wind tunnel fans. The fan noise varied directly with thrust regardless of whether thrust was varied by rotational speed or blade setting for the ranges studied.

  15. Control of low-frequency noise for piping systems via the design of coupled band gap of acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Li, Yanfei; Shen, Huijie; Zhang, Linke; Su, Yongsheng; Yu, Dianlong

    2016-07-01

    Acoustic wave propagation and sound transmission in a metamaterial-based piping system with Helmholtz resonator (HR) attached periodically are studied. A transfer matrix method is developed to conduct the investigation. Calculational results show that the introduction of periodic HRs in the piping system could generate a band gap (BG) near the resonant frequency of the HR, such that the bandwidth and the attenuation effect of HR improved notably. Bragg type gaps are also exist in the system due to the systematic periodicity. By plotting the BG as functions of HR parameters, the effect of resonator parameters on the BG behavior, including bandwidth, location and attenuation performance, etc., is examined. It is found that Bragg-type gap would interplay with the resonant-type gap under some special situations, thereby giving rise to a super-wide coupled gap. Further, explicit formulation for BG exact coupling is extracted and some key parameters on modulating the width and the attenuation coefficient of coupled gaps are investigated. The coupled gap can be located to any frequency range as one concerned, thus rendering the low-frequency noise control feasible in a broad band range.

  16. Acoustic chaos

    SciTech Connect

    Lauterborn, W.; Parlitz, U.; Holzfuss, J.; Billo, A.; Akhatov, I.

    1996-06-01

    Acoustic cavitation, a complex, spatio-temporal dynamical system, is investigated with respect to its chaotic properties. The sound output, the {open_quote}{open_quote}noise{close_quote}{close_quote}, is subjected to time series analysis. The spatial dynamics of the bubble filaments is captured by high speed holographic cinematography and subsequent digital picture processing from the holograms. Theoretical models are put forward for describing the pattern formation. {copyright} {ital 1996 American Institute of Physics.}

  17. 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.

  18. Measurements of Low-Frequency Acoustic Attenuation in Soils.

    DTIC Science & Technology

    2007-11-02

    Engineering Research Laboratory to design an acoustic subsurface imaging system, a set of experiments was conducted in which the attenuation and the velocity...support of the U.S. Army Construction Engineering Research Laboratory’s efforts to design an acoustic subsurface imaging system which would ideally be...of acoustic waves such as those generated by a subsurface imaging system. An experiment reported in the literature characterized the acoustic

  19. 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.

  20. Acoustic Characterization of Grass-cover Ground

    DTIC Science & Technology

    2014-11-20

    ABSTRACT A custom designed acoustic impedance tube was used to measure acoustic properties ofnonconsolidated materials, specifically soils and grass...covered ground. The tube was config- ured vertically for studying acoustic properties of granular materials i.e. soil and dirt. Software was developed to...collect data and calibrate the impedance tube . An equivalent fluid model for describing sound propagation in rigid fi·ame porous media was used to

  1. Acoustic Characterization of Mesoscale Objects

    SciTech Connect

    Chinn, D; Huber, R; Chambers, D; Cole, G; Balogun, O; Spicer, J; Murray, T

    2007-03-13

    This report describes the science and engineering performed to provide state-of-the-art acoustic capabilities for nondestructively characterizing mesoscale (millimeter-sized) objects--allowing micrometer resolution over the objects entire volume. Materials and structures used in mesoscale objects necessitate the use of (1) GHz acoustic frequencies and (2) non-contacting laser generation and detection of acoustic waves. This effort demonstrated that acoustic methods at gigahertz frequencies have the necessary penetration depth and spatial resolution to effectively detect density discontinuities, gaps, and delaminations. A prototype laser-based ultrasonic system was designed and built. The system uses a micro-chip laser for excitation of broadband ultrasonic waves with frequency components reaching 1.0 GHz, and a path-stabilized Michelson interferometer for detection. The proof-of-concept for mesoscale characterization is demonstrated by imaging a micro-fabricated etched pattern in a 70 {micro}m thick silicon wafer.

  2. Acoustic dose and acoustic dose-rate.

    PubMed

    Duck, Francis

    2009-10-01

    Acoustic dose is defined as the energy deposited by absorption of an acoustic wave per unit mass of the medium supporting the wave. Expressions for acoustic dose and acoustic dose-rate are given for plane-wave conditions, including temporal and frequency dependencies of energy deposition. The relationship between the acoustic dose-rate and the resulting temperature increase is explored, as is the relationship between acoustic dose-rate and radiation force. Energy transfer from the wave to the medium by means of acoustic cavitation is considered, and an approach is proposed in principle that could allow cavitation to be included within the proposed definitions of acoustic dose and acoustic dose-rate.

  3. SY 02-1 DESIGNING HYPERTENSION TREATMENT TRIALS.

    PubMed

    Kjeldsen, Sverre

    2016-09-01

    Results of outcome trials form the basis for treatment guidelines in hypertension. Further outcome trials are needed wherever there are gaps in knowledge. Thus, rationale for setting up and performing and outcome trial with investment of large resources is based on a strong hypothesis.Second, an outcome trial must be done with sufficient statistical power. Power is calculated from the risk level of the people to be investigated and the event rate, the expected benefit of the agent to be investigated and the number of treatment years (number of participants involved and years in the study). The agent and comparators are selected in line with the hypothesis and detailed attention is given to dosing, format, timing etc.Inclusion criteria should be harmonized with the hypothesis and need for power, and exclusion criteria are mostly standard. A pilot study or exploratory assessment whether the potential participants exist in the population and can be recruited within reasonable time is needed. The organization with various committees must be set up according to international standard and financial support secured. Patient report forms must be carefully developed in order to catch all details and be supported by a study manual with instructions to investigators.Measurements of blood pressure in and out of office need special attention. Selection of the primary endpoint is crucial for the success, and secondary endpoint should be identified at the outset. Important sub-studies should be designed already at this stage and included into written informed consent for approval by regulatory agents before study start. The protocol should include statements regarding interims analyses, usually at one and two thirds of accumulated primary endpoints, and a protocol may benefit from being endpoint driven and no futility stopping.

  4. The treatment of severe child aggression (TOSCA) study: Design challenges

    PubMed Central

    2011-01-01

    Background Polypharmacy (the concurrent use of more than one psychoactive drug) and other combination interventions are increasingly common for treatment of severe psychiatric problems only partly responsive to monotherapy. This practice and research on it raise scientific, clinical, and ethical issues such as additive side effects, interactions, threshold for adding second drug, appropriate target measures, and (for studies) timing of randomization. One challenging area for treatment is severe child aggression. Commonly-used medications, often in combination, include psychostimulants, antipsychotics, mood stabilizers, and alpha-2 agonists, which vary considerably in terms of perceived safety and efficacy. Results In designing our NIMH-funded trial of polypharmacy, we focused attention on the added benefit of a second drug (risperidone) to the effect of the first (stimulant). We selected these two drugs because their associated adverse events might neutralize each other (e.g., sleep delay and appetite decrease from stimulant versus sedation and appetite increase from antipsychotic). Moreover, there was considerable evidence of efficacy for each drug individually for the management of ADHD and child aggression. The study sample comprised children (ages 6-12 years) with both diagnosed ADHD and disruptive behavior disorder (oppositional-defiant or conduct disorder) accompanied by severe physical aggression. In a staged sequence, the medication with the least problematic adverse effects (stimulant) was openly titrated in 3 weeks to optimal effect. Participants whose behavioral symptoms were not normalized received additional double-blind medication, either risperidone or placebo, by random assignment. Thus children whose behavioral symptoms were normalized with stimulant medication were not exposed to an antipsychotic. All families participated in an empirically-supported parent training program for disruptive behavior, so that the actual comparison was stimulant

  5. Results of acoustic testing of the JT8D-109 refan engines

    NASA Technical Reports Server (NTRS)

    Burdsall, E. A.; Brochu, F. P.; Scaramella, V. M.

    1975-01-01

    A JT8D engine was modified to reduce jet noise levels by 6-8 PNdB at takeoff power without increasing fan generated noise levels. Designated the JT8D-109, the modified engines featured a larger single stage fan, and acoustic treatment in the fan discharge ducts. Noise levels were measured on an outdoor test facility for eight engine/acoustic treatment configurations. Compared to the baseline JT8D, the fully treated JT8D-109 showed reductions of 6 PNdB at takeoff, and 11 PNdB at a typical approach power setting.

  6. Simulation-based conceptual design of an acoustic metamaterial with full band gap using an air-based 1-3 piezoelectric composite for ultrasonic noise control

    NASA Astrophysics Data System (ADS)

    Rezaei, Shahrokh; Eskandari-Ghadi, Morteza; Rahimian, Mohammad

    2017-02-01

    This paper aims at proposing a novel type of acoustic metamaterials with complete band gap composed of piezoelectric rods with square array as inclusions embedded in an air background (matrix). A modified plane wave expansion method accompanied with the principles of the Bloch-Floquet method with electromechanical coupling effect and also impedance spectra are used to get a band frequency and to investigate the passband for the selected cut of piezoelectric rods. We investigate both the electromechanical coupling coefficient and mechanical quality factor and their dependency to passband and bandwidth, which depends on both the density and the wave impedance of the matrix and the inclusions (rods). The ratio of the volume of inclusion to the matrix is used to define the fill factor or the so-called inclusion ratio, to introduce the bandwidth as a function of that. Furthermore, the fabrication method is presented in this paper. The results make a suitable foundation for design purposes and may develop an inherently passive ultrasonic noise control. In addition, the results provide the required guidance for a simulation-based design of elastic wave filters or wave guide that might be useful in high-precision mechanical systems operated in certain frequency ranges and switches made of piezoelectric materials; they also propose a novel type of elastic metamaterials, which is independent of the wave direction and has an equal sensitivity in all directions in which it reacts omnidirectionally and mitigates the occupational noise exposure.

  7. Acoustic mechanical feedthroughs

    NASA Astrophysics Data System (ADS)

    Sherrit, Stewart; Walkemeyer, Phillip; Bao, Xiaoqi; Bar-Cohen, Yoseph; Badescu, Mircea

    2013-04-01

    Electromagnetic motors can have problems when operating in extreme environments. In addition, if one needs to do mechanical work outside a structure, electrical feedthroughs are required to transport the electric power to drive the motor. In this paper, we present designs for driving rotary and linear motors by pumping stress waves across a structure or barrier. We accomplish this by designing a piezoelectric actuator on one side of the structure and a resonance structure that is matched to the piezoelectric resonance of the actuator on the other side. Typically, piezoelectric motors can be designed with high torques and lower speeds without the need for gears. One can also use other actuation materials such as electrostrictive, or magnetostrictive materials in a benign environment and transmit the power in acoustic form as a stress wave and actuate mechanisms that are external to the benign environment. This technology removes the need to perforate a structure and allows work to be done directly on the other side of a structure without the use of electrical feedthroughs, which can weaken the structure, pipe, or vessel. Acoustic energy is pumped as a stress wave at a set frequency or range of frequencies to produce rotary or linear motion in a structure. This method of transferring useful mechanical work across solid barriers by pumping acoustic energy through a resonant structure features the ability to transfer work (rotary or linear motion) across pressure or thermal barriers, or in a sterile environment, without generating contaminants. Reflectors in the wall of barriers can be designed to enhance the efficiency of the energy/power transmission. The method features the ability to produce a bi-directional driving mechanism using higher-mode resonances. There are a variety of applications where the presence of a motor is complicated by thermal or chemical environments that would be hostile to the motor components and reduce life and, in some instances, not be

  8. Acoustic Mechanical Feedthroughs

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Walkemeyer, Phillip; Bao, Xiaoqi; Bar-Cohen, Yoseph; Badescu, Mircea

    2013-01-01

    Electromagnetic motors can have problems when operating in extreme environments. In addition, if one needs to do mechanical work outside a structure, electrical feedthroughs are required to transport the electric power to drive the motor. In this paper, we present designs for driving rotary and linear motors by pumping stress waves across a structure or barrier. We accomplish this by designing a piezoelectric actuator on one side of the structure and a resonance structure that is matched to the piezoelectric resonance of the actuator on the other side. Typically, piezoelectric motors can be designed with high torques and lower speeds without the need for gears. One can also use other actuation materials such as electrostrictive, or magnetostrictive materials in a benign environment and transmit the power in acoustic form as a stress wave and actuate mechanisms that are external to the benign environment. This technology removes the need to perforate a structure and allows work to be done directly on the other side of a structure without the use of electrical feedthroughs, which can weaken the structure, pipe, or vessel. Acoustic energy is pumped as a stress wave at a set frequency or range of frequencies to produce rotary or linear motion in a structure. This method of transferring useful mechanical work across solid barriers by pumping acoustic energy through a resonant structure features the ability to transfer work (rotary or linear motion) across pressure or thermal barriers, or in a sterile environment, without generating contaminants. Reflectors in the wall of barriers can be designed to enhance the efficiency of the energy/power transmission. The method features the ability to produce a bi-directional driving mechanism using higher-mode resonances. There are a variety of applications where the presence of a motor is complicated by thermal or chemical environments that would be hostile to the motor components and reduce life and, in some instances, not be

  9. Radiosurgery of acoustic neurinomas

    SciTech Connect

    Flickinger, J.C.; Lunsford, L.D.; Coffey, R.J.; Linskey, M.E.; Bissonette, D.J.; Maitz, A.H.; Kondziolka, D. )

    1991-01-15

    Eighty-five patients with acoustic neurinomas underwent stereotactic radiosurgery with the gamma unit at the University of Pittsburgh (Pittsburgh, PA) during its first 30 months of operation. Neuroimaging studies performed in 40 patients with more than 1 year follow-up showed that tumors were smaller in 22 (55%), unchanged in 17 (43%), and larger in one (2%). The 2-year actuarial rates for preservation of useful hearing and any hearing were 46% and 62%, respectively. Previously undetected neuropathies of the trigeminal (n = 12) and facial nerves (n = 14) occurred 1 week to 1 year after radiosurgery (median, 7 and 6 months, respectively), and improved at median intervals of 13 and 8 months, respectively, after onset. Hearing loss was significantly associated with increasing average tumor diameter (P = 0.04). No deterioration of any cranial nerve function has yet developed in seven patients with average tumor diameters less than 10 mm. Radiosurgery is an important treatment alternative for selected acoustic neurinoma patients.

  10. 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.

  11. The design, characterization, and comparison of MEMS comb-drive acoustic emission transducers with the principles of area-change and gap-change

    NASA Astrophysics Data System (ADS)

    Kabir, Minoo; Saboonchi, Hossain; Ozevin, Didem

    2015-04-01

    Comb-drive transducers are made of interdigitized fingers formed by the stationary part known as stator and the moving part known as rotor, and based on the transduction principle of capacitance change. They can be designed as area-change or gap-change mechanism to convert the mechanical signal at in-plane direction into electrical output. The comb-drive transducers can be utilized to differentiate the wave motion in orthogonal directions when they are utilized with the outof- plane transducers. However, their sensitivity is weak to detect the wave motion released by newly formed damage surfaces. In this study, Micro-Electro-Mechanical System (MEMS) comb-drive Acoustic Emission (AE) transducer designs with two different mechanisms are designed, characterized and compared for sensing high frequency wave propagation. The MEMS AE transducers are manufactured using MetalMUMPs (Metal Multi-User MEMS Processes), which use electroplating technique for highly elevated microstructure geometries. Each type of the transducers is numerically modeled using COMSOL Multiphysics program in order to determine the sensitivity based on the applied load. The transducers are experimentally characterized and compared to the numerical models. The experiments include laser excitation to control the direction of the wave generation, and actual crack growth monitoring of aluminum 7075 specimens loaded under fatigue. Behavior and responses of the transducers are compared based on the parameters such as waveform signature, peak frequency, damping, sensitivity, and signal to noise ratio. The comparisons between the measured parameters are scaled according to the respective capacitance of each sensor in order to determine the most sensitive design geometry.

  12. Acoustic absorption by sunspots

    NASA Technical Reports Server (NTRS)

    Braun, D. C.; Labonte, B. J.; Duvall, T. L., Jr.

    1987-01-01

    The paper presents the initial results of a series of observations designed to probe the nature of sunspots by detecting their influence on high-degree p-mode oscillations in the surrounding photosphere. The analysis decomposes the observed oscillations into radially propagating waves described by Hankel functions in a cylindrical coordinate system centered on the sunspot. From measurements of the differences in power between waves traveling outward and inward, it is demonstrated that sunspots appear to absorb as much as 50 percent of the incoming acoustic waves. It is found that for all three sunspots observed, the amount of absorption increases linearly with horizontal wavenumber. The effect is present in p-mode oscillations with wavelengths both significantly larger and smaller than the diameter of the sunspot umbrae. Actual absorption of acoustic energy of the magnitude observed may produce measurable decreases in the power and lifetimes of high-degree p-mode oscillations during periods of high solar activity.

  13. Electromagnetic acoustic imaging.

    PubMed

    Emerson, Jane F; Chang, David B; McNaughton, Stuart; Jeong, Jong Seob; Shung, K K; Cerwin, Stephen A

    2013-02-01

    Electromagnetic acoustic imaging (EMAI) is a new imaging technique that uses long-wavelength RF electromagnetic (EM) waves to induce ultrasound emission. Signal intensity and image contrast have been found to depend on spatially varying electrical conductivity of the medium in addition to conventional acoustic properties. The resultant conductivity- weighted ultrasound data may enhance the diagnostic performance of medical ultrasound in cancer and cardiovascular applications because of the known changes in conductivity of malignancy and blood-filled spaces. EMAI has a potential advantage over other related imaging techniques because it combines the high resolution associated with ultrasound detection with the generation of the ultrasound signals directly related to physiologically important electrical properties of the tissues. Here, we report the theoretical development of EMAI, implementation of a dual-mode EMAI/ultrasound apparatus, and successful demonstrations of EMAI in various phantoms designed to establish feasibility of the approach for eventual medical applications.

  14. Acoustic properties of biodegradable nonwovens

    NASA Astrophysics Data System (ADS)

    Yilmaz, Nazire Deniz

    The purpose of this study is to provide a better understanding of acoustical properties of nonwovens, and to model the noise control behavior in terms of material and treatment parameters. A review of existing models on sound absorption of fibrous materials, coupled with experimental data will help in modeling sound absorption in multi-layer needle-punched nonwoven fabrics of different fibers: hemp, polylactide, polypropylene, and glassfiber. The effects of several treatments, which the materials may undergo during sound absorber manufacturing, namely alkalization, compression and heat treatments are investigated. The collected data is evaluated by experts. Expert evaluation further provides information about market demands for sound absorbers, and the perception of the designed nonwovens through the eyes of professionals. This research provides a contribution to the body of knowledge on the sound absorption properties of nonwovens, and provides a better understanding of the effects of some manufacturing processes on nonwovens' noise control performance and contributes to the wider adoption of nonwovens as sound absorbers.

  15. Acoustic agglomeration of power plant fly ash for environmental and hot gas cleanup

    SciTech Connect

    Reethof, G.; Koopmann, G.H.

    1989-12-01

    This two year research program has the objectives of completing the several investigations associated with the use of high intensity acoustic energy to agglomerate micron and submicron sized particles in fly ash aerosols in order to provide the necessary scientific knowledge and design criteria for the specification of technically and economically viable intermediate flue gas treatment of coal fired power plants. Goals are to further the understanding of certain fundamental processes by means of theoretical and experimental investigations to include this knowledge in an advanced computerized model of the agglomeration processes. Tests with the acoustic agglomeration facilities available in Penn State's new High Intensity Acoustic Laboratory were to be used to verify the results from the acoustic agglomeration simulations. Research work continued on high power, high efficiency sirens with special emphasis on the nonlinear acoustic phenomena and novel means of significantly increasing siren efficiency. A study was carried out to evaluate the economics of conventional coal fired power plant clean-up systems using acoustic agglomeration as an intermediate flue gas treatment. 154 refs., 152 figs., 30 tabs.

  16. A SMART design to optimize treatment strategies for patient and family caregiver outcomes.

    PubMed

    Song, Mi-Kyung; DeVito Dabbs, Annette; Ward, Sandra E

    2016-01-01

    Sequential multiple randomization trial (SMART) designs are experimental designs used to identify treatment strategies that maximize targeted health outcomes. SMART designs are receiving greater attention in nursing and other health disciplines to develop multicomponent interventions that are tailored to the patient's (or family caregiver's) needs and preferences. A SMART design resembles a traditional randomized controlled trial (RCT) design in that it scientifically examines intervention effects with randomization. However, the two designs address very different research inquiries. In this article, we compare traditional RCT designs and SMART designs, describe the adaptive treatment framework that underlies SMART designs and key features of SMART designs, and illustrate the application of a SMART design to develop an adaptive palliative care treatment to improve patient and caregiver outcomes.

  17. Acoustic transducer for nuclear reactor monitoring

    DOEpatents

    Ahlgren, Frederic F.; Scott, Paul F.

    1977-01-01

    A transducer to monitor a parameter and produce an acoustic signal from which the monitored parameter can be recovered. The transducer comprises a modified Galton whistle which emits a narrow band acoustic signal having a frequency dependent upon the parameter being monitored, such as the temperature of the cooling media of a nuclear reactor. Multiple locations within a reactor are monitored simultaneously by a remote acoustic receiver by providing a plurality of transducers each designed so that the acoustic signal it emits has a frequency distinct from the frequencies of signals emitted by the other transducers, whereby each signal can be unambiguously related to a particular transducer.

  18. Transducer Arrays Suitable for Acoustic Imaging

    DTIC Science & Technology

    1978-06-01

    attention is placed on achieving high transduction efficiency and angular beam - widths of at least ±15°• T. Design techniques based on the transmission line...approximation so that the acoustic beam is caused to come to a focus in the exact analogue to a normal lens. The reference phase delays necessary to...fccus the acoustic beam are provided by a tapped surface acoustic wave delay line. A surface Ji acoustic wave is launched down the delay line with a

  19. Conceptual design study of advanced acoustic composite nacelle. [for achieving reductions in community noise and operating expense

    NASA Technical Reports Server (NTRS)

    Goodall, R. G.; Painter, G. W.

    1975-01-01

    Conceptual nacelle designs for wide-bodied and for advanced-technology transports were studied with the objective of achieving significant reductions in community noise with minimum penalties in airplane weight, cost, and in operating expense by the application of advanced composite materials to nacelle structure and sound suppression elements. Nacelle concepts using advanced liners, annular splitters, radial splitters, translating centerbody inlets, and mixed-flow nozzles were evaluated and a preferred concept selected. A preliminary design study of the selected concept, a mixed flow nacelle with extended inlet and no splitters, was conducted and the effects on noise, direct operating cost, and return on investment determined.

  20. Strong acoustic coupling to a superconducting qubit

    NASA Astrophysics Data System (ADS)

    Gustafsson, Martin; Aref, Thomas; Frisk Kockum, Anton; Ekström, Maria; Johansson, Göran; Delsing, Per

    2014-03-01

    Micromechanical resonators can be used to store quantum information, as shown in several recent experiments. These resonators typically have the form of membranes or beams, and phonons are localized to their vibrational eigenmodes. We present a different kind of mechanical quantum device, where propagating phonons serve as carriers for quantum information. At the core of our device is a superconducting qubit, designed to couple to Surface Acoustic Waves (SAW) in the underlying substrate through the piezoelectric effect. This type of coupling can be very strong, and in our case exceeds the coupling to any external electromagnetic modes. The acoustic waves propagate freely on the surface of the substrate, and we use a remote electro-acoustic transducer to address the qubit acoustically and listen to its emission of phonons. This presentation focuses on the basic properties of our acoustic quantum system, and we include experimental data that demonstrate the quantized coupling between the qubit and the propagating acoustic waves.

  1. How To Achieve Good Library Acoustics.

    ERIC Educational Resources Information Center

    Wiens, Janet

    2003-01-01

    Discusses how to create a good acoustical environment for college libraries, focusing on requirements related to the HVAC system and lighting, and noting the importance of good maintenance. A sidebar looks at how to design and achieve the most appropriate HVAC and lighting systems for optimum library acoustics. (SM)

  2. ACOUSTIC FORMING FOR ENHANCED DEWATERING AND FORMATION

    SciTech Connect

    Cyrus K Aidun

    2007-11-30

    The next generation of forming elements based on acoustic excitation to increase drainage and enhances formation both with on-line control and profiling capabilities has been investigated in this project. The system can be designed and optimized based on the fundamental experimental and computational analysis and investigation of acoustic waves in a fiber suspension flow and interaction with the forming wire.

  3. Design considerations for wastewater treatment by reverse osmosis.

    PubMed

    Bartels, C R; Wilf, M; Andes, K; Iong, J

    2005-01-01

    Reverse Osmosis is finding increasing use for the treatment of municipal and industrial wastewaters due to the growing demand for high quality water in large urban areas. The growing success of membranes in this application is related to improved process designs and improved membrane products. Key factors which have been determined to result in successful operation of large-scale plants will be discussed. Factors which play a key role in the use of RO membranes include ultra or microfiltration pretreatment, low fouling membranes, flux rate, recovery and control of fouling and scaling. In particular, high flux rates can be used when UF or MF pretreatment is used. These technologies remove most of the suspended particles that would normally cause heavy fouling of lead elements. Typically, fluxes in the range of 17-21 lmh lead to cleaning frequencies in the range of 3-4 months. By combining the use of membrane pretreatment and chloramination of the feed water through chlorine addition, two of the primary sources of RO membrane fouling can be controlled. The use of chloramine has become a proven means to control biofouling in a membrane for wastewater applications. The other significant problems for RO membranes result from organics fouling by dissolved organics and scaling due to saturation of marginally soluble salts. The former can be a significant problem for membranes, due to the strong attraction forces. To some extent, these can be mitigated by making the membrane surface more hydrophilic or changing the charge of the membrane surface. To minimize fouling, many plants are turning to low fouling membranes. Extensive studies have demonstrated that the membrane surface is hydrophilic, neutrally charged over a broad pH range, and more resistant to organic adsorption. Also, an analysis of the potential scaling issues will be reviewed. In particular, calcium phosphate has been found to be one of the key scalants that will limit RO system recovery rate. Calcium

  4. Whole systems thinking for sustainable water treatment design

    NASA Astrophysics Data System (ADS)

    Huggins, Mitchell Tyler

    Microbial fuel cell (MFC) technology could provide a low cost alternative to conventional aerated wastewater treatment, however there has been little comparison between MFC and aeration treatment using real wastewater substrate. This study attempts to directly compare the wastewater treatment efficiency and energy consumption and generation among three reactor systems, a traditional aeration process, a simple submerged MFC configuration, and a control reactor acting similar as natural lagoons. Results showed that all three systems were able to remove >90% of COD, but the aeration used shorter time (8 days) then the MFC (10 days) and control reactor (25 days). Compared to aeration, the MFC showed lower removal efficiency in high COD concentration but much higher efficiency when the COD is low. Only the aeration system showed complete nitrification during the operation, reflected by completed ammonia removal and nitrate accumulation. Suspended solid measurements showed that MFC reduced sludge production by 52-82% as compared to aeration, and it also saved 100% of aeration energy. Furthermore, though not designed for high power generation, the MFC reactor showed a 0.3 Wh/g COD/L or 24 Wh/m3 (wastewater treated) net energy gain in electricity generation. These results demonstrate that MFC technology could be integrated into wastewater infrastructure to meet effluent quality and save operational cost. The high cost and life-cycle impact of electrode materials is one major barrier to the large scale application of microbial fuel cells (MFC). We also demonstrate that biomass-derived black carbon (biochar), could be a more cost effective and sustainable alternative to granular activated carbon (GAC) and graphite granule (GG) electrodes. In a comparison study, two biochar materials made from lodgepole pine sawdust pellets (BCp) and lodgepole pine woodchips (BCc), gassified at a highest heat temperature (HHT) of 1000°C under a heating rate of 16°C/min, showed a

  5. Acoustics Research of Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Gao, Ximing; Houston, Janice D.

    2014-01-01

    The liftoff phase induces some of the highest acoustic loading over a broad frequency for a launch vehicle. These external acoustic environments are used in the prediction of the internal vibration responses of the vehicle and components. Thus, predicting these liftoff acoustic environments is critical to the design requirements of any launch vehicle but there are challenges. Present liftoff vehicle acoustic environment prediction methods utilize stationary data from previously conducted hold-down tests; i.e. static firings conducted in the 1960's, to generate 1/3 octave band Sound Pressure Level (SPL) spectra. These data sets are used to predict the liftoff acoustic environments for launch vehicles. To facilitate the accuracy and quality of acoustic loading, predictions at liftoff for future launch vehicles such as the Space Launch System (SLS), non-stationary flight data from the Ares I-X were processed in PC-Signal in two forms which included a simulated hold-down phase and the entire launch phase. In conjunction, the Prediction of Acoustic Vehicle Environments (PAVE) program was developed in MATLAB to allow for efficient predictions of sound pressure levels (SPLs) as a function of station number along the vehicle using semiempirical methods. This consisted, initially, of generating the Dimensionless Spectrum Function (DSF) and Dimensionless Source Location (DSL) curves from the Ares I-X flight data. These are then used in the MATLAB program to generate the 1/3 octave band SPL spectra. Concluding results show major differences in SPLs between the hold-down test data and the processed Ares IX flight data making the Ares I-X flight data more practical for future vehicle acoustic environment predictions.

  6. 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.

  7. 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.

  8. Investigations of detail design issues for the high speed acoustic wind tunnel using a 60th scale model tunnel. Part 2: Tests with the closed circuit

    NASA Technical Reports Server (NTRS)

    Barna, P. Stephen

    1991-01-01

    This report summarizes the tests on the 1:60 scale model of the High Speed Acoustic Wind Tunnel (HSAWT) performed during the period June - August 1991. Throughout the testing the tunnel was operated in the 'closed circuit mode,' that is when the airflow was set up by an axial flow fan, which was located inside the tunnel circuit and was directly driven by a motor. The tests were first performed with the closed test section and were subsequently repeated with the open test section, the latter operating with the nozzle-diffuser at its optimum setting. On this subject, reference is made to the report (1) issued January 1991, under contract 17-GFY900125, which summarizes the result obtained with the tunnel operating in the 'open circuit mode.' The tests confirmed the viability of the tunnel design, and the flow distributions in most of the tunnel components were considered acceptable. There were found, however, some locations where the flow distribution requires improvement. This applies to the flow upstream of the fan where the flow was found skewed, thus affecting the flow downstream. As a result of this, the flow appeared separated at the end of the large diffuser at the outer side. All tests were performed at NASA LaRC.

  9. 14 CFR 25.856 - Thermal/Acoustic insulation materials.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Thermal/Acoustic insulation materials. 25... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Fire Protection § 25.856 Thermal/Acoustic insulation materials. (a) Thermal/acoustic insulation material installed in...

  10. 14 CFR 23.856 - Thermal/acoustic insulation materials.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Thermal/acoustic insulation materials. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Fire Protection § 23.856 Thermal/acoustic insulation materials. Thermal/acoustic...

  11. 14 CFR 25.856 - Thermal/Acoustic insulation materials.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Thermal/Acoustic insulation materials. 25... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Fire Protection § 25.856 Thermal/Acoustic insulation materials. (a) Thermal/acoustic insulation material installed in...

  12. 14 CFR 25.856 - Thermal/Acoustic insulation materials.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Thermal/Acoustic insulation materials. 25... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Fire Protection § 25.856 Thermal/Acoustic insulation materials. (a) Thermal/acoustic insulation material installed in...

  13. 14 CFR 25.856 - Thermal/Acoustic insulation materials.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Thermal/Acoustic insulation materials. 25... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Fire Protection § 25.856 Thermal/Acoustic insulation materials. (a) Thermal/acoustic insulation material installed in...

  14. 14 CFR 25.856 - Thermal/Acoustic insulation materials.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Thermal/Acoustic insulation materials. 25... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Fire Protection § 25.856 Thermal/Acoustic insulation materials. (a) Thermal/acoustic insulation material installed in...

  15. 14 CFR 23.856 - Thermal/acoustic insulation materials.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Thermal/acoustic insulation materials. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Fire Protection § 23.856 Thermal/acoustic insulation materials. Thermal/acoustic...

  16. 14 CFR 23.856 - Thermal/acoustic insulation materials.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Thermal/acoustic insulation materials. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Fire Protection § 23.856 Thermal/acoustic insulation materials. Thermal/acoustic...

  17. Studies of acoustical properties of bulk porous flexible materials

    NASA Technical Reports Server (NTRS)

    Lambert, R. F.

    1984-01-01

    Acoustic prediction and measurement of bulk porous materials with flexible frames is investigated. The acoustic properties of Kevlar 29 are examined. Various acoustic tests are employed to determine impedance, sound wave propagation, and wave pressure equations for the highly porous fiber composites. The derivation of design equations and future research goals are included.

  18. Movement Patterns and Site Utilization of Fishes as Determined by Acoustic Telemetry: Implications for the Design of Marine Reserves

    DTIC Science & Technology

    2003-09-01

    PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) NOAAs Stellwagen Bank National Marine...the design of marine reserves James Lindholm 1,2, Peter Auster 2, Les Kaufman 3, Steven Miller 4, and Greg Stone 5 1) NOAA’s Stellwagen Bank ...going telemetry studies in the western North Atlantic: Stellwagen Bank National Marine Sanctuary (SBNMS) in the Gulf of Maine and in the northern

  19. A Preliminary Engineering Design of Intravascular Dual-Frequency Transducers for Contrast-Enhanced Acoustic Angiography and Molecular Imaging

    PubMed Central

    Ma, Jianguo; Martin, K. Heath; Dayton, Paul A.; Jiang, Xiaoning

    2014-01-01

    Current intravascular ultrasound (IVUS) probes are not optimized for contrast detection because of their design for high-frequency fundamental-mode imaging. However, data from transcutaneous contrast imaging suggests the possibility of utilizing contrast ultrasound for molecular imaging or vasa vasorum assessment to further elucidate atherosclerotic plaque deposition. This paper presents the design, fabrication, and characterization of a small-aperture (0.6 × 3 mm) IVUS probe optimized for high-frequency contrast imaging. The design utilizes a dual-frequency (6.5 MHz/30 MHz) transducer arrangement for exciting microbubbles at low frequencies (near their resonance) and detecting their broadband harmonics at high frequencies, minimizing detected tissue backscatter. The prototype probe is able to generate nonlinear microbubble response with more than 1.2 MPa of rarefractional pressure (mechanical index: 0.48) at 6.5 MHz, and is also able to detect microbubble response with a broadband receiving element (center frequency: 30 MHz, −6-dB fractional bandwidth: 58.6%). Nonlinear super-harmonics from microbubbles flowing through a 200-μm-diameter micro-tube were clearly detected with a signal-to-noise ratio higher than 12 dB. Preliminary phantom imaging at the fundamental frequency (30 MHz) and dual-frequency super-harmonic imaging results suggest the promise of small aperture, dual-frequency IVUS transducers for contrast-enhanced IVUS imaging. PMID:24801226

  20. Design and evaluation of a higher-order spherical microphone/ambisonic sound reproduction system for the acoustical assessment of concert halls

    NASA Astrophysics Data System (ADS)

    Clapp, Samuel W.

    Previous studies of the perception of concert hall acoustics have generally employed two methods for soliciting listeners' judgments. One method is to have listeners rate the sound in a hall while physically present in that hall. The other method is to make recordings of different halls and seat positions, and then recreate the environment for listeners in a laboratory setting via loudspeakers or headphones. In situ evaluations offer a completely faithful rendering of all aspects of the concert hall experience. However, many variables cannot be controlled and the short duration of auditory memory precludes an objective comparison of different spaces. Simulation studies allow for more control over various aspects of the evaluations, as well as A/B comparisons of different halls and seat positions. The drawback is that all simulation methods suffer from limitations in the accuracy of reproduction. If the accuracy of the simulation system is improved, then the advantages of the simulation method can be retained, while mitigating its disadvantages. Spherical microphone array technology has received growing interest in the acoustics community in recent years for many applications including beamforming, source localization, and other forms of three-dimensional sound field analysis. These arrays can decompose a measured sound field into its spherical harmonic components, the spherical harmonics being a set of spatial basis functions on the sphere that are derived from solving the wave equation in spherical coordinates. Ambisonics is a system for two- and three-dimensional spatialized sound that is based on recreating a sound field from its spherical harmonic components. Because of these shared mathematical underpinnings, ambisonics provides a natural way to present fully spatialized renderings of recordings made with a spherical microphone array. Many of the previously studied applications of spherical microphone arrays have used a narrow frequency range where the array

  1. Effects of Intensive Voice Treatment (the Lee Silverman Voice Treatment [LSVT]) on Vowel Articulation in Dysarthric Individuals with Idiopathic Parkinson Disease: Acoustic and Perceptual Findings

    ERIC Educational Resources Information Center

    Sapir, Shimon; Spielman, Jennifer L.; Ramig, Lorraine O.; Story, Brad H.; Fox, Cynthia

    2007-01-01

    Purpose: To evaluate the effects of intensive voice treatment targeting vocal loudness (the Lee Silverman Voice Treatment [LSVT]) on vowel articulation in dysarthric individuals with idiopathic Parkinson's disease (PD). Method: A group of individuals with PD receiving LSVT (n = 14) was compared to a group of individuals with PD not receiving LSVT…

  2. Social anxiety disorder: designing a pharmacologic treatment strategy.

    PubMed

    Pollack, M H

    1999-01-01

    Growing appreciation of the prevalence of and morbid sequelae associated with social anxiety disorder has focused increasing interest on the development of effective treatment strategies. A number of pharmacologic interventions, including the monoamine oxidase inhibitors, reversible inhibitors of monoamine oxidase A, beta-blockers, benzodiazepines, and selective serotonin reuptake inhibitors, have demonstrated efficacy for the treatment of social anxiety disorder. The choice of initial treatment depends on a variety of factors including comorbidity, prior treatment history, patient preference, and adverse effect profile. This article will examine the effectiveness of various pharmacologic agents for the treatment of social anxiety disorder, discuss considerations for long-term management, and review strategies for optimizing treatment in patients who are partially responsive or unresponsive to initial therapy.

  3. High transmission acoustic focusing by impedance-matched acoustic meta-surfaces

    NASA Astrophysics Data System (ADS)

    Al Jahdali, Rasha; Wu, Ying

    2016-01-01

    Impedance is an important issue in the design of acoustic lenses because mismatched impedance is detrimental to real focusing applications. Here, we report two designs of acoustic lenses that focus acoustic waves in water and air, respectively. They are tailored by acoustic meta-surfaces, which are rigid thin plates decorated with periodically distributed sub-wavelength slits. Their respective building blocks are constructed from the coiling-up spaces in water and the layered structures in air. Analytic analysis based on coupled-mode theory and transfer matrix reveals that the impedances of the lenses are matched to those of the background media. With these impedance-matched acoustic lenses, we demonstrate the acoustic focusing effect by finite-element simulations.

  4. My 65 years in acoustics

    NASA Astrophysics Data System (ADS)

    Beranek, Leo L.

    2004-05-01

    My entry into acoustics began as research assistant to Professor F. V. Hunt at Harvard University. I received my doctorate in 1940 and directed the Electro-Acoustic Laboratory at Harvard from October 1940 until September 1945. In 1947, I became a tenured associate professor at MIT, and, with Richard H. Bolt, formed the consulting firm Bolt and Beranek, that later included Robert B. Newman, becoming BBN. My most significant contributions before 1970 were design of wedge-lined anechoic chambers, systemization of noise reduction in ventilation systems, design of the world's largest muffler for the testing of supersonic jet engines at NASA's Lewis Laboratory in Cleveland, speech interference level, NC noise criterion curves, heading New York Port Authority's noise study that resulted in mufflers on jet aircraft, and steep aircraft climb procedures, and publishing books titled, Acoustical Measurements, Acoustics, Noise Reduction, Noise and Vibration Control, and Music, Acoustics and Architecture. As President of BBN, I supervised the formation of the group that built and operated the ARPANET (1969), which, when split in two (using TCP/IP protocol) became the INTERNET (1984). Since then, I have written two books on Concert Halls and Opera Houses and have consulted on four concert halls and an opera house.

  5. My 65 years in acoustics

    NASA Astrophysics Data System (ADS)

    Beranek, Leo L.

    2001-05-01

    My entry into acoustics began as research assistant to Professor F. V. Hunt at Harvard University. I received my doctorate in 1940 and directed the Electro-Acoustic Laboratory at Harvard from October 1940 until September 1945. In 1947, I became a tenured associate professor at MIT, and, with Richard H. Bolt, formed the consulting firm Bolt and Beranek, that later included Robert B. Newman, becoming BBN. My most significant contributions before 1970 were design of wedge-lined anechoic chambers, systemization of noise reduction in ventilation systems, design of the world's largest muffler for the testing of supersonic jet engines at NASA's Lewis Laboratory in Cleveland, speech interference level, NC noise criterion curves, heading New York Port Authority's noise study that resulted in mufflers on jet aircraft, and steep aircraft climb procedures, and publishing books titled, Acoustical Measurements, Acoustics, Noise Reduction, Noise and Vibration Control, and Music, Acoustics and Architecture. As President of BBN, I supervised the formation of the group that built and operated the ARPANET (1969), which, when split in two (using TCP/IP protocol) became the INTERNET (1984). Since then, I have written two books on Concert Halls and Opera Houses and have consulted on four concert halls and an opera house.

  6. Design and evaluation of a novel microphone-based mechanomyography sensor with cylindrical and conical acoustic chambers.

    PubMed

    Posatskiy, A O; Chau, T

    2012-10-01

    Mechanomyography has recently been proposed as a control modality for alternative access technologies for individuals with disabilities. However, MMG recordings are highly susceptible to contamination from limb movements. Pressure-based transducers are touted to be the most robust to external movement although there is some debate about their optimal chamber geometry, in terms of low frequency gain and spectral flatness. To investigate the question of preferred geometry, transducers with cylindrical and conical chambers of varying dimensions were designed, manufactured and tested. Using a computer-controlled electrodynamic shaker, the frequency response of each chamber geometry was empirically derived. Of the cylindrical chambers, the highest gain and the flattest frequency response was exhibited by a chamber 10 mm in diameter and 5-7 mm in height. However, conical chambers offered an average rise in gain of 6.79 ± 1.06 dB/Hz over that achievable with cylindrical geometries. The highest gain and flattest response was achieved with a transducer consisting of a low-frequency MEMS microphone, a 4 μm aluminized mylar membrane and a rigid conical chamber 7 mm in diameter and 5mm in height. This design is recommended for MMG applications where limb movement is prevalent.

  7. Fractionated Stereotactic Radiotherapy in the Treatment of Vestibular Schwannoma (Acoustic Neuroma): Predicting the Risk of Hydrocephalus;Vestibular schwannoma; Hydrocephalus; Fractionated; Stereotactic radiotherapy

    SciTech Connect

    Powell, Ceri; Micallef, Caroline; Gonsalves, Adam; Wharram, Bev; Ashley, Sue; Brada, Michael

    2011-07-15

    Purpose: To determine the incidence and predictive factors for the development of hydrocephalus in patients with acoustic neuromas (AN) treated with fractionated stereotactic radiotherapy. Patients and Methods: Seventy-two patients with AN were treated with fractionated stereotactic radiotherapy between 1998 and 2007 (45-50 Gy in 25-30 fractions over 5 to 6 weeks). The pretreatment MRI scan was assessed for tumor characteristics and anatomic distortion independently of subsequent outcome and correlated with the risk of hydrocephalus. Results: At a median follow-up of 49 months (range, 1-120 months), 5-year event-free survival was 95%. Eight patients (11%) developed hydrocephalus within 19 months of radiotherapy, which was successfully treated. On univariate analysis, pretreatment factors predictive of hydrocephalus were maximum diameter (p = 0.005), proximity to midline (p = 0.009), displacement of the fourth ventricle (p = 0.02), partial effacement of the fourth ventricle (p < 0.001), contact with the medulla (p = 0.005), and more brainstem structures (p = 0.004). On multivariate analysis, after adjusting for fourth ventricular effacement, no other variables remained independently associated with hydrocephalus formation. Conclusions: Fractionated stereotactic radiotherapy results in excellent tumor control of AN, albeit with a risk of developing hydrocephalus. Patients at high risk, identified as those with larger tumors with partial effacement of the fourth ventricle before treatment, should be monitored more closely during follow-up. It would also be preferable to offer treatment to patients with progressive AN while the risk of hydrocephalus is low, before the development of marked distortion of fourth ventricle before tumor diameter significantly exceeds 2 cm.

  8. 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.

  9. 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.

  10. 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.

  11. Dynamic acoustic tractor beams

    SciTech Connect

    Mitri, F. G.

    2015-03-07

    Pulling a sphere and vibrating it around an equilibrium position by amplitude-modulation in the near-field of a single finite circular piston transducer is theoretically demonstrated. Conditions are found where a fluid hexane sphere (with arbitrary radius) chosen as an example, centered on the axis of progressive propagating waves and submerged in non-viscous water, experiences an attractive (steady) force pulling it towards the transducer, as well as an oscillatory force forcing it to vibrate back-and-forth. Numerical predictions for the dynamic force illustrate the theory and suggest an innovative method in designing dynamic acoustical tractor beams.

  12. Autonomous Adaptive Acoustic Relay Positioning

    DTIC Science & Technology

    2013-09-01

    species as well as uncover underwater archaeological sites [21]. Remotely-operated vehicles (ROVs) are designed for remote human control and use with a...distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT We consider the problem of maximizing underwater acoustic data transmission by...practical method of underwater wireless communication and improving channel throughput and reliability is key to improving the capabilities of underwater

  13. SLUDGE TREATMENT PROJECT KOP CONCEPTUAL DESIGN CONTROL DECISION REPORT

    SciTech Connect

    CARRO CA

    2010-03-09

    This control decision addresses the Knock-Out Pot (KOP) Disposition KOP Processing System (KPS) conceptual design. The KPS functions to (1) retrieve KOP material from canisters, (2) remove particles less than 600 {micro}m in size and low density materials from the KOP material, (3) load the KOP material into Multi-Canister Overpack (MCO) baskets, and (4) stage the MCO baskets for subsequent loading into MCOs. Hazard and accident analyses of the KPS conceptual design have been performed to incorporate safety into the design process. The hazard analysis is documented in PRC-STP-00098, Knock-Out Pot Disposition Project Conceptual Design Hazard Analysis. The accident analysis is documented in PRC-STP-CN-N-00167, Knock-Out Pot Disposition Sub-Project Canister Over Lift Accident Analysis. Based on the results of these analyses, and analyses performed in support of MCO transportation and MCO processing and storage activities at the Cold Vacuum Drying Facility (CVDF) and Canister Storage Building (CSB), control decision meetings were held to determine the controls required to protect onsite and offsite receptors and facility workers. At the conceptual design stage, these controls are primarily defined by their safety functions. Safety significant structures, systems, and components (SSCs) that could provide the identified safety functions have been selected for the conceptual design. It is anticipated that some safety SSCs identified herein will be reclassified based on hazard and accident analyses performed in support of preliminary and detailed design.

  14. [Trimetazidine (Vastarel 20 mg) and electro-acoustic stimulation in the treatment of tinnitus. Apropos of 64 cases].

    PubMed

    Desaulty, A; Gelaude, A

    1990-01-01

    This open pilot study was carried out with the intent of assessing the pertinence of combining Vastarel 20 mg with electroacoustic stimulation, as opposed to using solely the electroacoustic stimulation method in the management of subjective tinnitus. Enrolled in the study were 64 patients presenting with subjective tinnitus, 50% of which were related to vascular disorders. Following the entry visit (clinical examination, pure-tone audiometry, Metz' test, auditory evoked potentials, CT scans of the internal auditory canal), the patients underwent six 45-minute sessions of electroacoustic stimulation at one-week intervals. Half the patients followed this sole treatment, while the other half was immediately started on Vastarel 20 mg (3 tablets daily) concurrently with the first electroacoustic stimulation session and maintained on this regimen for 3 months. The electroacoustic stimulation (EAS) device used (Tinitop) was operated by emitting a synchronic sound signal mediated by a cask and an electric signal mediated by adhesive electrodes placed in the pretragal area. Results Results were analyzed through history-taking on the 45th and 90th days following the onset of the treatment, subjective improvement of tinnitus being rated from 0% to 100% based on 25% scoring levels (0 = no effect; 100% = complete disappearance of tinnitus spells). At day 45, the proportion of good and very good results (50% improvement or more) was similar (56%), regardless of whether Vastarel 20 mg was or not associated with EAS therapy. On the other hand, the combination of Vastarel 20 mg with masking of tinnitus proved particularly useful in preventing recurrences.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Intensive Treatment of Dysarthria Secondary to Stroke

    ERIC Educational Resources Information Center

    Mahler, Leslie A.; Ramig, Lorraine O.

    2012-01-01

    This study investigated the impact of a well-defined behavioral dysarthria treatment on acoustic and perceptual measures of speech in four adults with dysarthria secondary to stroke. A single-subject A-B-A experimental design was used to measure the effects of the Lee Silverman Voice Treatment (LSVT[R]LOUD) on the speech of individual…

  16. Acoustic propagation in viscous fluid with uniform flow and a novel design methodology for ultrasonic flow meter.

    PubMed

    Chen, Yong; Huang, Yiyong; Chen, Xiaoqian

    2013-02-01

    Ultrasonic flow meter with non-invasive no-moving-parts construction has good prospective application for space on-orbit fluid gauging. In traditional pulse transit time flow meter, inconsistency of ultrasonic transducers leads to measurement error and plane wave theory, bases of transit time flow meter, is valuable only for low-frequency wave propagation in inviscid fluid and will lose feasibility when fluid viscosity is considered. In this paper, based on the hydrodynamics of viscous fluid, wave propagation with uniform flow profile is mathematically formulated and a novel solution for viscous fluid using potential theory is firstly presented. Then a novel design methodology of continuous ultrasonic flow meter is proposed, where high measurement rangeability and accuracy are guaranteed individually by solving the integral ambiguity using multi-tone wide laning strategy and the fractional phase shift using phase lock loop tracking method. A comparison with transit time ultrasonic flow meter shows the advantage of proposed methodology. In the end, parametric analysis of viscosity on wave propagation and ultrasonic flow meter is compressively investigated.

  17. Treatment of Early-Onset Schizophrenia Spectrum Disorders (TEOSS): Rationale, Design, and Methods

    ERIC Educational Resources Information Center

    McClellan, Jon; Sikich, Linmarie; Findling, Robert L.; Frazier, Jean A.; Vitiello, Benedetto; Hlastala, Stefanie A.; Williams, Emily; Ambler, Denisse; Hunt-Harrison, Tyehimba; Maloney, Ann E.; Ritz, Louise; Anderson, Robert; Hamer, Robert M.; Lieberman, Jeffrey A.

    2007-01-01

    Objective: The Treatment of Early Onset Schizophrenia Spectrum Disorders Study is a publicly funded clinical trial designed to compare the therapeutic benefits, safety, and tolerability of risperidone, olanzapine, and molindone in youths with early-onset schizophrenia spectrum disorders. The rationale, design, and methods of the Treatment of Early…

  18. 7 CFR 201.34 - Kind, variety, and type; treatment substances; designation as hybrid.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...; designation as hybrid. 201.34 Section 201.34 Agriculture Regulations of the Department of Agriculture..., variety, and type; treatment substances; designation as hybrid. (a) Indistinguishable seed and treatment... therefor, provided the name does not apply to more than one kind and is not misleading. (c)...

  19. 7 CFR 201.34 - Kind, variety, and type; treatment substances; designation as hybrid.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...; designation as hybrid. 201.34 Section 201.34 Agriculture Regulations of the Department of Agriculture..., variety, and type; treatment substances; designation as hybrid. (a) Indistinguishable seed and treatment... therefor, provided the name does not apply to more than one kind and is not misleading. (c)...

  20. 7 CFR 201.34 - Kind, variety, and type; treatment substances; designation as hybrid.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...; designation as hybrid. 201.34 Section 201.34 Agriculture Regulations of the Department of Agriculture..., variety, and type; treatment substances; designation as hybrid. (a) Indistinguishable seed and treatment... therefor, provided the name does not apply to more than one kind and is not misleading. (c)...

  1. 7 CFR 201.34 - Kind, variety, and type; treatment substances; designation as hybrid.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...; designation as hybrid. 201.34 Section 201.34 Agriculture Regulations of the Department of Agriculture..., variety, and type; treatment substances; designation as hybrid. (a) Indistinguishable seed and treatment... therefor, provided the name does not apply to more than one kind and is not misleading. (c)...

  2. Reconfigurable origami-inspired acoustic waveguides.

    PubMed

    Babaee, Sahab; Overvelde, Johannes T B; Chen, Elizabeth R; Tournat, Vincent; Bertoldi, Katia

    2016-11-01

    We combine numerical simulations and experiments to design a new class of reconfigurable waveguides based on three-dimensional origami-inspired metamaterials. Our strategy builds on the fact that the rigid plates and hinges forming these structures define networks of tubes that can be easily reconfigured. As such, they provide an ideal platform to actively control and redirect the propagation of sound. We design reconfigurable systems that, depending on the externally applied deformation, can act as networks of waveguides oriented along one, two, or three preferential directions. Moreover, we demonstrate that the capability of the structure to guide and radiate acoustic energy along predefined directions can be easily switched on and off, as the networks of tubes are reversibly formed and disrupted. The proposed designs expand the ability of existing acoustic metamaterials and exploit complex waveguiding to enhance control over propagation and radiation of acoustic energy, opening avenues for the design of a new class of tunable acoustic functional systems.

  3. Reconfigurable origami-inspired acoustic waveguides

    PubMed Central

    Babaee, Sahab; Overvelde, Johannes T. B.; Chen, Elizabeth R.; Tournat, Vincent; Bertoldi, Katia

    2016-01-01

    We combine numerical simulations and experiments to design a new class of reconfigurable waveguides based on three-dimensional origami-inspired metamaterials. Our strategy builds on the fact that the rigid plates and hinges forming these structures define networks of tubes that can be easily reconfigured. As such, they provide an ideal platform to actively control and redirect the propagation of sound. We design reconfigurable systems that, depending on the externally applied deformation, can act as networks of waveguides oriented along one, two, or three preferential directions. Moreover, we demonstrate that the capability of the structure to guide and radiate acoustic energy along predefined directions can be easily switched on and off, as the networks of tubes are reversibly formed and disrupted. The proposed designs expand the ability of existing acoustic metamaterials and exploit complex waveguiding to enhance control over propagation and radiation of acoustic energy, opening avenues for the design of a new class of tunable acoustic functional systems. PMID:28138527

  4. Acoustic non-diffracting Airy beam

    SciTech Connect

    Lin, Zhou; Guo, Xiasheng Tu, Juan; Ma, Qingyu; Wu, Junru; Zhang, Dong

    2015-03-14

    The acoustic non-diffracting Airy beam as its optical counterpart has unique features of self-bending and self-healing. The complexity of most current designs handicaps its applications. A simple design of an acoustic source capable of generating multi-frequency and broad-band acoustic Airy beam has been theoretically demonstrated by numerical simulations. In the design, a piston transducer is corrugated to induce spatial phase variation for transducing the Airy function. The piston's surface is grooved in a pattern that the width of each groove corresponds to the half wavelength of Airy function. The resulted frequency characteristics and its dependence on the size of the piston source are also discussed. This simple design may promote the wide applications of acoustic Airy beam particularly in the field of medical ultrasound.

  5. Design of treatment trials for functional gastrointestinal disorders

    PubMed Central

    van Zanten, S J O V.; Talley, N; Bytzer, P; Klein, K; Whorwell, P; Zinsmeister, A

    1999-01-01

    Until recently many clinical trials of functional gastrointestinal disorders (FGIDs) suffered from important weaknesses in trial design, study execution, and data analysis. This makes it difficult to determine whether truly efficacious therapies exist for these disorders. One of the important methodologic problems is the absence of validated outcome measures and lack of consensus among stakeholders on how to measure outcome. Currently much of the effort is being put into the development of validated outcome measures for several of the FGIDs. The randomized, controlled trial with parallel groups is the design of choice. In this report, guidelines are given for the basic architecture of intervention studies of FGIDs. Further studies on design issues are required to ensure the recommendations will become evidence based in the future.


Keywords: clinical trial; random allocation; functional gastrointestinal disorder(s); dyspepsia; functional dyspepsia; irritable bowel syndrome; evidence based medicine; study design; outcome measures; Rome II PMID:10457048

  6. Acoustic Emission Signatures During Failure of Vertebra and Long Bone.

    PubMed

    Goodwin, Brian D; Pintar, Frank A; Yoganandan, Narayan

    2017-03-14

    Clinical classification of an injury has traditionally involved medical imaging, patient history, and physical examination. The pathogenesis or process of injury has been viewed as a crucial component to estimating fracture stability and direct treatment. However, injury classification systems generally exclude pathogenesis and injury mechanisms because these components are often difficult to elucidate. Furthermore, the development of bone damage relative to the mechanical response is difficult to quantify, which limits the ability to define injury and develop injury criteria. Past advents of new knowledge about the mechanisms and progression of fracture have refined safety standards and engineering design for limiting injury. Post-hoc methodologies for identifying and classifying injuries for post-mortem human surrogate (PMHS) research are well established. Though bone fractures can be classified post hoc, questions remain. Surface acoustic sensing (SAS) is an effective approach to augment PMHS experimentation. The objective was to develop and validate an acoustic-emission-based method to characterize bone fractures during injurious loading conditions using acoustic emissions (AEs) in two bone types: vertebral body (VB) and long bone (LB). The newly developed method incorporated the Stockwell transform to estimate the relative energy release rate (RERR) from bone fracture using acoustic signal processing. Fractures were characterized through AE burst durations and frequency content. Results indicated that VB fractures from compression are prolonged processes compared to LB fracture, which was staccato in nature. Significant (p < 0.01) differences between burst duration and frequency content were identified between the two bone types.

  7. Acoustic Emission Health Monitoring of Fill Purge COPV's Used in Aerospace and Automotive Applications and Designed for Long Cycle Life

    NASA Technical Reports Server (NTRS)

    Waller, Jess

    2013-01-01

    Cumulative composite damage in composite pressure vessels (CPVs) currently is not monitored on-orbit. Consequently, hazards due to catastrophic burst before leak (BBL) or compromised CPV reliability cannot be ascertained or mitigated, posing a risk to crew and mission assurance. The energy associated with CPV rupture can be significant, especially with high pressure gases are under containment, and the energy releases can be severe enough to cause injury, death, loss of assets or mission. Dual-Use Rationale: CPVs similar to those used by NASA on ISS, for example, are finding increasing use in automotive and transportation industry applications. These CPVs generally have a nonload sharing liner and are repeatedly filled over their service lifetime, typically with hydrogen or compressed natural gas (CNG). The same structural health monitoring equipment and software developed by NASA WSTF for evaluating, in real-time, the health of NASA CPVs on ISS will be used to evaluate the health of automotive CPVs, the only differences being the type and design of the CPV, and the in-service lifetime pressure histories. HSF Need(s)/Performance Characteristic(s) Supported: 1) Enable on-board vehicle systems management for mission critical functions at destinations with > 3 second time delay 2) Enable autonomous nominal operations and FDIR for crewed and un-crewed systems 3) Reduce on-board crew time to sustain and manage vehicle by factor of 2x at destinations with > 6 second time delay (see Crew Autonomy sheet) 4) Reduce earth-based mission ops "back room engineering" requirements for distant mission support delay (see Mission Autonomy sheet)

  8. Acoustic method respiratory rate monitoring is useful in patients under intravenous anesthesia.

    PubMed

    Ouchi, Kentaro; Fujiwara, Shigeki; Sugiyama, Kazuna

    2017-02-01

    Respiratory depression can occur during intravenous general anesthesia without tracheal intubation. A new acoustic method for respiratory rate monitoring, RRa(®) (Masimo Corp., Tokyo, Japan), has been reported to show good reliability in post-anesthesia care and emergency units. The purpose of this study was to investigate the reliability of the acoustic method for measurement of respiratory rate during intravenous general anesthesia, as compared with capnography. Patients with dental anxiety undergoing dental treatment under intravenous anesthesia without tracheal intubation were enrolled in this study. Respiratory rate was recorded every 30 s using the acoustic method and capnography, and detectability of respiratory rate was investigated for both methods. This study used a cohort study design. In 1953 recorded respiratory rate data points, the number of detected points by the acoustic method (1884, 96.5 %) was significantly higher than that by capnography (1682, 86.1 %) (P < 0.0001). In the intraoperative period, there was a significant difference in the LOA (95 % limits of agreement of correlation between difference and average of the two methods)/ULLOA (under the lower limit of agreement) in terms of use or non-use of a dental air turbine (P < 0.0001). In comparison between capnography, the acoustic method is useful for continuous monitoring of respiratory rate in spontaneously breathing subjects undergoing dental procedures under intravenous general anesthesia. However, the acoustic method might not accurately detect in cases in with dental air turbine.

  9. PORTABLE ACOUSTIC MONITORING PACKAGE (PAMP)

    SciTech Connect

    John l. Loth; Gary J. Morris; George M. Palmer; Richard Guiler; Deepak Mehra

    2003-07-01

    The 1st generation acoustic monitoring package was designed to detect and analyze weak acoustic signals inside natural gas transmission lines. Besides a microphone it housed a three-inch diameter aerodynamic acoustic signal amplifier to maximize sensitivity to leak induced {Delta}p type signals. The theory and test results of this aerodynamic signal amplifier was described in the master's degree thesis of our Research Assistant Deepak Mehra who is about to graduate. To house such a large three-inch diameter sensor required the use of a steel 300-psi rated 4 inch weld neck flange, which itself weighed already 29 pounds. The completed 1st generation Acoustic Monitoring Package weighed almost 100 pounds. This was too cumbersome to mount in the field, on an access port at a pipeline shut-off valve. Therefore a 2nd generation and truly Portable Acoustic Monitor was built. It incorporated a fully self-contained {Delta}p type signal sensor, rated for line pressures up to 1000 psi with a base weight of only 6 pounds. This is the Rosemont Inc. Model 3051CD-Range 0, software driven sensor, which is believed to have industries best total performance. Its most sensitive unit was purchased with a {Delta}p range from 0 to 3 inch water. This resulted in the herein described 2nd generation: Portable Acoustic Monitoring Package (PAMP) for pipelines up to 1000 psi. Its 32-pound total weight includes an 18-volt battery. Together with a 3 pound laptop with its 4-channel data acquisition card, completes the equipment needed for field acoustic monitoring of natural gas transmission pipelines.

  10. Measurement of acoustical characteristics of mosques in Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Abdou, Adel A.

    2003-03-01

    The study of mosque acoustics, with regard to acoustical characteristics, sound quality for speech intelligibility, and other applicable acoustic criteria, has been largely neglected. In this study a background as to why mosques are designed as they are and how mosque design is influenced by worship considerations is given. In the study the acoustical characteristics of typically constructed contemporary mosques in Saudi Arabia have been investigated, employing a well-known impulse response. Extensive field measurements were taken in 21 representative mosques of different sizes and architectural features in order to characterize their acoustical quality and to identify the impact of air conditioning, ceiling fans, and sound reinforcement systems on their acoustics. Objective room-acoustic indicators such as reverberation time (RT) and clarity (C50) were measured. Background noise (BN) was assessed with and without the operation of air conditioning and fans. The speech transmission index (STI) was also evaluated with and without the operation of existing sound reinforcement systems. The existence of acoustical deficiencies was confirmed and quantified. The study, in addition to describing mosque acoustics, compares design goals to results obtained in practice and suggests acoustical target values for mosque design. The results show that acoustical quality in the investigated mosques deviates from optimum conditions when unoccupied, but is much better in the occupied condition.

  11. Measurement of acoustical characteristics of mosques in Saudi Arabia.

    PubMed

    Abdou, Adel A

    2003-03-01

    The study of mosque acoustics, with regard to acoustical characteristics, sound quality for speech intelligibility, and other applicable acoustic criteria, has been largely neglected. In this study a background as to why mosques are designed as they are and how mosque design is influenced by worship considerations is given. In the study the acoustical characteristics of typically constructed contemporary mosques in Saudi Arabia have been investigated, employing a well-known impulse response. Extensive field measurements were taken in 21 representative mosques of different sizes and architectural features in order to characterize their acoustical quality and to identify the impact of air conditioning, ceiling fans, and sound reinforcement systems on their acoustics. Objective room-acoustic indicators such as reverberation time (RT) and clarity (C50) were measured. Background noise (BN) was assessed with and without the operation of air conditioning and fans. The speech transmission index (STI) was also evaluated with and without the operation of existing sound reinforcement systems. The existence of acoustical deficiencies was confirmed and quantified. The study, in addition to describing mosque acoustics, compares design goals to results obtained in practice and suggests acoustical target values for mosque design. The results show that acoustical quality in the investigated mosques deviates from optimum conditions when unoccupied, but is much better in the occupied condition.

  12. An acoustic double fishnet using Helmholtz resonators.

    PubMed

    Murray, A R J; Summers, I R; Sambles, J R; Hibbins, A P

    2014-09-01

    The acoustic transmission of a closely spaced pair of patterned and perforated rigid plates is explored in air. The structure resembles an acoustic double fishnet design, with each plate modified such that the gap between them acts as an array of Helmholtz resonators. This allows the center frequency of the stop band to be reduced by a factor greater than 2 from the value obtained for the conventional acoustic double fishnet design. Experimental results accord well with the predictions of a finite element model.

  13. Process Design of Wastewater Treatment for the NREL Cellulosic Ethanol Model

    SciTech Connect

    Steinwinder, T.; Gill, E.; Gerhardt, M.

    2011-09-01

    This report describes a preliminary process design for treating the wastewater from NREL's cellulosic ethanol production process to quality levels required for recycle. In this report Brown and Caldwell report on three main tasks: 1) characterization of the effluent from NREL's ammonia-conditioned hydrolyzate fermentation process; 2) development of the wastewater treatment process design; and 3) development of a capital and operational cost estimate for the treatment concept option. This wastewater treatment design was incorporated into NREL's cellulosic ethanol process design update published in May 2011 (NREL/TP-5100-47764).

  14. Photoacoustic cell using elliptical acoustic focusing

    NASA Technical Reports Server (NTRS)

    Heritier, J.-M.; Fouquet, J. E.; Siegman, A. E.

    1982-01-01

    A photoacoustic cell has been developed in the form of an elliptical cylinder in which essentially all the acoustic energy generated by a laser beam passing down one axis is focused onto a cylindrical acoustic tranducer located along the other axis. Preliminary measurements on a liquid-filled cell of this design show high sensitivity and a notably clean impulse response. A similar design may be useful for photoacoustic measurements in vapors as well.

  15. [The effects of acoustic overstimulation].

    PubMed

    Häusler, R

    2004-01-01

    Basic aspects of acoustic trauma are presented. Exposure to loud noise leads to an acoustic traumatization with a temporary threshold shift initially and, with increasing exposure, intensity and duration, a permanent hearing loss. Impulse sound such as hammer blows on metal, gun shots and other detonations reaching peak levels of 160 to 180 dB is particularly hazardous to the inner ear. Playing loud musical instruments such as trumpets or percussion may also lead to hearing damage. Less dangerous than often believed is listening to electronically amplified music with walkmen, at discos or rock concerts. The reason is that, while the sound level is quite high, the particularly dangerous sound peaks are absent, as loudspeakers usually have an output limit of 110-120 dB. Traffic noise (cars, trains, air planes) is usually not threatening to the ear, but it may represent a considerable subjective annoyance and a stress factor leading to psychosomatic disturbances (neurovegetative symptoms, sleeping disorders). An effective treatment for the acoustic trauma is still missing. The systematic and consequent prophylaxis either with individual ear protectors (plugs or ear muffs) or by reducing the noise level at the source by means of isolation, encapsulation, or by using motors that are less noisy remains very important. Increasing awareness of acoustic pollution and preventive means have led to a reduction in the incidence of the acoustic trauma in the last decades.

  16. Water Treatment Pilot Plant Design Manual: Low Flow Conventional/Direct Filtration Water Treatment Plant for Drinking Water Treatment Studies

    EPA Science Inventory

    This manual highlights the project constraints and concerns, and includes detailed design calculations and system schematics. The plant is based on engineering design principles and practices, previous pilot plant design experiences, and professional experiences and may serve as ...

  17. Tunable acoustic waveguide based on vibro-acoustic metamaterials with shunted piezoelectric unit cells

    NASA Astrophysics Data System (ADS)

    Kwon, Byung-Jin; Jung, Jin-Young; Lee, Dooho; Park, Kwang-Chun; Oh, Il-Kwon

    2015-10-01

    We propose a new class of acoustic waveguides with tunable bandgaps (TBs) by using vibro-acoustic metamaterials with shunted periodic piezoelectric unit cells. The unit metamaterial cells that consist of a single crystal piezoelectric transducer and an electrical shunt circuit are designed to induce a strong vibro-acousto-electrical coupling, resulting in a tunable acoustic bandgap as well as local structural resonance and Bragg scattering bandgaps. The present results show that the TB frequency can be actively controlled and the transmission loss of the acoustic wave can be greatly improved by simply changing the inductance values in the shunt circuit.

  18. Acoustics, Noise, and Buildings. Revised Edition 1969.

    ERIC Educational Resources Information Center

    Parkin, P. H.; Humphreys, H. R.

    The fundamental physical concepts needed in any appreciation of acoustical problems are discussed by a scientist and an architect. The major areas of interest are--(1) the nature of sound, (2) the behavior of sound in rooms, (3) the design of rooms for speech, (4) the design of rooms for music, (5) the design of studios, (6) the design of high…

  19. Classroom acoustics: Three pilot studies

    NASA Astrophysics Data System (ADS)

    Smaldino, Joseph J.

    2005-04-01

    This paper summarizes three related pilot projects designed to focus on the possible effects of classroom acoustics on fine auditory discrimination as it relates to language acquisition, especially English as a second language. The first study investigated the influence of improving the signal-to-noise ratio on the differentiation of English phonemes. The results showed better differentiation with better signal-to-noise ratio. The second studied speech perception in noise by young adults for whom English was a second language. The outcome indicated that the second language learners required a better signal-to-noise ratio to perform equally to the native language participants. The last study surveyed the acoustic conditions of preschool and day care classrooms, wherein first and second language learning occurs. The survey suggested an unfavorable acoustic environment for language learning.

  20. Opto-acoustic thrombolysis

    DOEpatents

    Celliers, Peter; Da Silva, Luiz; Glinsky, Michael; London, Richard; Maitland, Duncan; Matthews, Dennis; Fitch, Pat

    2000-01-01

    This invention is a catheter-based device for generating an ultrasound excitation in biological tissue. Pulsed laser light is guided through an optical fiber to provide the energy for producing the acoustic vibrations. The optical energy is deposited in a water-based absorbing fluid, e.g. saline, thrombolytic agent, blood or thrombus, and generates an acoustic impulse in the fluid through thermoelastic and/or thermodynamic mechanisms. By pulsing the laser at a repetition rate (which may vary from 10 Hz to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus or treating vasospasm. The catheter can also incorporate thrombolytic drug treatments as an adjunct therapy and it can be operated in conjunction with ultrasonic detection equipment for imaging and feedback control and with optical sensors for characterization of thrombus type and consistency.

  1. Density-near-zero using the acoustically induced transparency of a Fano acoustic resonator

    NASA Astrophysics Data System (ADS)

    Elayouch, A.; Addouche, M.; Farhat, M.; Amin, M.; Bağcı, H.; Khelif, A.

    2016-11-01

    We report experimental results of near-zero mass density involving an acoustic metamaterial supporting Fano resonance. For this, we designed and fabricated an acoustic resonator with two closely coupled modes and measured its transmission properties. Our study reveals that the phenomenon of acoustically induced transparency is accompanied by an effect of near-zero density. Indeed, the dynamic effective parameters obtained from experimental data show the presence of a frequency band where the effective mass density is close to zero, with high transmission levels reaching 0.7. Furthermore, we demonstrate that such effective parameters lead to wave guiding in a 90-degrees-bent channel. This kind of acoustic metamaterial can, therefore, give rise to acoustic functions like controlling the wavefront, which may lead to very promising applications in acoustic cloacking or imaging.

  2. Far-field image magnification for acoustic waves using anisotropic acoustic metamaterials.

    PubMed

    Ao, Xianyu; Chan, C T

    2008-02-01

    A kind of two-dimensional acoustic metamaterial is designed so that it exhibits strong anisotropy along two orthogonal directions. Based on the rectangular equal frequency contour of this metamaterial, magnifying lenses for acoustic waves, analogous to electromagnetic hyperlenses demonstrated recently in the optical regime, can be realized. Such metamaterial may offer applications in imaging for systems that obey scalar wave equations.

  3. Dynamic changes following combined treatment with gentamicin and ethacrynic acid with and without acoustic stimulation. Cellular uptake and functional correlates.

    PubMed

    Hayashida, T; Hiel, H; Dulon, D; Erre, J P; Guilhaume, A; Aran, J M

    1989-01-01

    Regional selectivity of gentamicin (GM) ototoxicity was studied in guinea pigs (GPs) using electrophysiological, morphological, autoradiographic and immunohistological observations following combined treatment with GM (150 mg/kg i.m.) and ethacrynic acid (EA) (30 mg/kg i.c. or i.v., 1.5 h after GM injection). The GPs were either continuously stimulated every 5 min with a series of 256 clicks (70 dB peSPL, 10/s) during 3 h for monitoring fast changes in VIII nerve compound action potential (CAP) after the EA injection, and thereafter kept in the animal quarters (background noise of 60 dB SPL) (group I), or similarly monitored for only 10 min after the EA injection and thereafter kept in a soundproof room (around 0 dB SPL) (group II). Whenever GM labelling was observed it was localized only in the sensory hair cells. From 3 h after EA injection, the GPs in group I presented threshold elevations in the high-frequency region, which progressed to 60-80 dB at all frequencies at and after 48 h. Parallel to the threshold pattern, GM uptake in outer hair cells (OHCs) was seen with an increasing concentration from apex toward base from 3 to 24 h, while after 48 h almost all OHCs were destroyed and inner hair cells (IHCs) were marked by GM. In group II no changes in CAP thresholds were observed until more than 24 h, although GM was detected in the hair cells from 6 h on. At this early stage, the distribution of GM lacked a clear pattern, particularly without a clear apex-base gradient, and GM deposits were found only around the basal body. However in both groups, in late stage (greater than 24 h), the base-apex gradient was more pronounced and GM was found throughout the cell body, with a marked concentration below the cuticular plate. These results suggest that GM may penetrate hair cells around the basal body and that activating the cells by sound potentiates both GM uptake and its intracellular toxicity.

  4. Design Considerations for an Intensive Autism Treatment Centre

    ERIC Educational Resources Information Center

    Deochand, Neil; Conway, Alissa A.; Fuqua, R. Wayne

    2015-01-01

    Individuals with autistic spectrum disorder (ASD) who display severe and challenging behaviour sometimes require centre-based intensive applied behaviour analysis (ABA) therapy to meet their health, safety and educational needs. Unfortunately, despite the need for centre-based treatment, there is a paucity of empirical research on building and…

  5. A Course on Operational Considerations in Wastewater Treatment Plant Design. Student Manual.

    ERIC Educational Resources Information Center

    Stottler, Stag and Associates, San Antonio, TX.

    This manual was designed to furnish information for upgrading the design of wastewater treatment plant facilities and to serve as a resource for establishing criteria for upgrading these plants. The manual also furnishes information for modifying plant design to compensate for current organic and hydraulic overloads and/or to meet more stringent…

  6. PROCESS DESIGN MANUAL FOR SLUDGE TREATMENT AND DISPOSAL

    EPA Science Inventory

    The purpose of this manual is to provide the engineering community and related industry with a new source of information to be used in the planning, design, and operation of present and future wastewater pollution control facilities. This manual supplements this existing knowledg...

  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. Piezoelectric materials used in underwater acoustic transducers

    SciTech Connect

    Li, Huidong; Deng, Zhiqun; Carlson, Thomas J.

    2012-07-07

    Piezoelectric materials have been used in underwater acoustic transducers for nearly a century. In this paper, we reviewed four different types of piezoelectric materials: piezoelectric ceramics, single crystals, composites, and polymers, which are widely used in underwater acoustic transducers nowadays. Piezoelectric ceramics are the most dominant material type and are used as a single-phase material or one of the end members in composites. Piezoelectric single crystals offer outstanding electromechanical response but are limited by their manufacturing cost. Piezoelectric polymers provide excellent acoustic impedance matching and transducer fabrication flexibility although their piezoelectric properties are not as good as ceramics and single crystals. Composites combined the merits of ceramics and polymers and are receiving increased attention. The typical structure and electromechanical properties of each type of materials are introduced and discussed with respect to underwater acoustic transducer applications. Their advantages and disadvantages are summarized. Some of the critical design considerations when developing underwater acoustic transducers with these materials are also touched upon.

  9. Generation of acoustic helical wavefronts using metasurfaces

    NASA Astrophysics Data System (ADS)

    Esfahlani, Hussein; Lissek, Herve; Mosig, Juan R.

    2017-01-01

    It has been shown that acoustic waves with helical wavefronts can carry angular momentum, which can be transmitted towards a propagating medium. Such a wave field can be achieved by using a planar array of electroacoustic transducers, forming a given spatial distribution of phased sound sources which produce the desired helical wavefronts. Here, we introduce a technique to generate acoustic vortices, based on the passive acoustic metasurface concept. The proposed metasurface is composed of space-coiled cylindrical unit cells transmitting sound pressure with a controllable phase shift, which are arranged in a discretized circular configuration, and thus passively transforming an incident plane wavefront into the desired helical wavefront. This method presents the advantage of overcoming the restrictions on using many acoustic sources, and it is implemented with a transmitting metasurface which can be easily three-dimensionally printed. The proposed straightforward design principle can be adopted for easy production of acoustic angular momentum with minimum complexity and using a single source.

  10. Acoustical components of the Orpheum Theatre renovation

    NASA Astrophysics Data System (ADS)

    Conant, David A.

    2002-05-01

    The before and after acoustically-important listening conditions and measurements are described for a $14.2 million restoration and renovation of this 1,400-seat grand 1929 Movie Palace-at one time the tallest building in Phoenix. Great care was taken to restore all the acoustically good parts of the original design and to subtly modify the acoustically-troublesome parts (including severely focusing dome and sidewalls) so they looked the same but performed properly. A beautiful playhouse was achieved in 1997 with fine, fixed acoustics and conventional audio reinforcement, a surrounding Italian village, plenty of gilt, moving clouds and sunsets overhead. Today, the venue successfully hosts shows from performance art to ballet to jazz. It was not intended (acoustically) to serve classical music but does so on occasion.

  11. Acoustic rainbow trapping by coiling up space

    NASA Astrophysics Data System (ADS)

    Ni, Xu; Wu, Ying; Chen, Ze-Guo; Zheng, Li-Yang; Xu, Ye-Long; Nayar, Priyanka; Liu, Xiao-Ping; Lu, Ming-Hui; Chen, Yan-Feng

    2014-11-01

    We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

  12. What Is an Acoustic Neuroma

    MedlinePlus

    ... ANAUSA.org Connect with us! What is an Acoustic Neuroma? Each heading slides to reveal information. Important ... Acoustic Neuroma Important Points To Know About an Acoustic Neuroma An acoustic neuroma, also called a vestibular ...

  13. INTEC CPP-603 Basin Water Treatment System Closure: Process Design

    SciTech Connect

    Kimmitt, Raymond Rodney; Faultersack, Wendell Gale; Foster, Jonathan Kay; Berry, Stephen Michael

    2002-09-01

    This document describes the engineering activities that have been completed in support of the closure plan for the Idaho Nuclear Technology and Engineering Center (INTEC) CPP-603 Basin Water Treatment System. This effort includes detailed assessments of methods and equipment for performing work in four areas: 1. A cold (nonradioactive) mockup system for testing equipment and procedures for vessel cleanout and vessel demolition. 2. Cleanout of process vessels to meet standards identified in the closure plan. 3. Dismantlement and removal of vessels, should it not be possible to clean them to required standards in the closure plan. 4. Cleanout or removal of pipelines and pumps associated with the CPP-603 basin water treatment system. Cleanout standards for the pipes will be the same as those used for the process vessels.

  14. Geothermal injection treatment: process chemistry, field experiences, and design options

    SciTech Connect

    Kindle, C.H.; Mercer, B.W.; Elmore, R.P.; Blair, S.C.; Myers, D.A.

    1984-09-01

    The successful development of geothermal reservoirs to generate electric power will require the injection disposal of approximately 700,000 gal/h (2.6 x 10/sup 6/ 1/h) of heat-depleted brine for every 50,000 kW of generating capacity. To maintain injectability, the spent brine must be compatible with the receiving formation. The factors that influence this brine/formation compatibility and tests to quantify them are discussed in this report. Some form of treatment will be necessary prior to injection for most situations; the process chemistry involved to avoid and/or accelerate the formation of precipitate particles is also discussed. The treatment processes, either avoidance or controlled precipitation approaches, are described in terms of their principles and demonstrated applications in the geothermal field and, when such experience is limited, in other industrial use. Monitoring techniques for tracking particulate growth, the effect of process parameters on corrosion and well injectability are presented. Examples of brine injection, preinjection treatment, and recovery from injectivity loss are examined and related to the aspects listed above.

  15. Ultrasound acoustic metamaterials with double-negative parameters

    NASA Astrophysics Data System (ADS)

    Chen, Huaijun; Li, Hui; Zhai, Shilong; Ding, Changlin; Li, Jiamao; Luo, Chunrong; Zhao, Xiaopeng

    2016-05-01

    We experimentally demonstrate a double-negative acoustic metamaterial (AM) that combines a hollow tube and a split hollow sphere into a structurally simple perforated hollow tube with the ability to generate simultaneous resonances in water. The effective acoustic parameters extracted from the transmission and reflection coefficients confirmed that negative effective mass density and modulus were achieved from 36.68 kHz to 36.96 kHz, and the effective index was also negative in the same frequency range. In addition, further experimental measurements confirmed that the well-designed AM could realize slab focusing phenomenon. With the unique properties, the proposed AM presents potential applications in sub-wavelength imaging and medical ultrasound treatment.

  16. Study of signal treatment for a pulsed electro-acoustic measurement cell: a way of improving the transfer matrix condition number

    NASA Astrophysics Data System (ADS)

    Arnaout, M.; Baudoin, F.; Berquez, L.; Payan, D.

    2011-10-01

    This work is focused on the improvement of the condition number of the transfer function matrix in a pulsed electro-acoustic (PEA) cell. A numerical electro-acoustic model is developed with the software COMSOL. This model is one-dimensional and the system of equations with partial differential functions is solved using a finite element method in non-stationary situations. Using this model, we can establish the output voltage of the piezoelectric sensor and acoustic pressure at each point of the calculation domain. Our approach consists in recovering the charge distribution within the sample using a deconvolution method between the simulated output voltage and the transfer function of the PEA cell. Results show why some changes of the PEA cell such as the nature of materials or sensor geometry involve an ill-posed problem or ill-conditioned problem, and why other arrangements lead to a well-conditioned problem, more amenable to giving the appropriate solution.

  17. Wind turbine acoustic standards

    NASA Technical Reports Server (NTRS)

    Stephens, D. G.; Shepherd, K. P.; Grosveld, F.

    1981-01-01

    A program is being conducted to develop noise standards for wind turbines which minimize annoyance and which can be used to design specifications. The approach consists of presenting wind turbine noise stimuli to test subjects in a laboratory listening chamber. The responses of the subjects are recorded for a range of stimuli which encompass the designs, operating conditions, and ambient noise levels of current and future installations. Results to date have established the threshold of detectability for a range of impulsive stimuli of the type associated with blade/tower wake interactions. The status of the ongoing psychoacoustic tests, the subjective data, and the approach to the development of acoustic criteria/standards are described.

  18. Aeroelastic structural acoustic control.

    PubMed

    Clark, R L; Frampton, K D

    1999-02-01

    Static, constant-gain, output-feedback control compensators were designed to increase the transmission loss across a panel subjected to mean flow on one surface and a stationary, acoustic half-space on the opposite surface. The multi-input, multi-output control system was based upon the use of an array of colocated transducer pairs. The performance of the static-gain, output-feedback controller was compared to that of the full state-feedback controller using the same control actuator arrays, and was found to yield comparable levels of performance for practical limitations on control effort. Additionally, the resulting static compensators proved to be dissipative in nature, and thus the design varied little as a function of the aeroelastic coupling induced by the fluid-structure interaction under subsonic flow conditions. Several parametric studies were performed, comparing the effects of control-effort penalty as well as the number of transducer pairs used in the control system.

  19. Acoustic agglomeration of power plant fly ash: Quarterly technical report, November 5, 1986--February 5, 1987

    SciTech Connect

    Reethof, G.

    1987-03-20

    The objective of this project is to complete the investigations on the use of high intensity acoustic energy to agglomerate micron and submicron sized particulates in fly ash aerosols in order to provide the necessary scientific knowledge and design criteria for the specification of technically and economically viable intermediate flue gas treatment of coal fired power plants. The results of the project are to provide technical and economic information for the better development and evaluation of potential fine particulate control systems. The goals of the proposed work are to further the understanding of certain fundamental processes by means of theoretical and experimental investigations, to include this knowledge in an advanced computerized model of the agglomeration processes. Tests with the two acoustic agglomerators available in Penn State's new High Intensity Acoustics Laboratory will be used to verify the results from the agglomeration simulation. Research work will continue on high power, high efficiency sirens with special emphasis on the nonlinear acoustic phenomena and novel means of significantly increasing siren efficiency. A study will be carried out to evaluate the economics of conventional coal fired power plant clean-up systems using acoustic agglomerators as intermediate flue gas treatment.

  20. Acoustic Transmitters for Underwater Neutrino Telescopes

    PubMed Central

    Ardid, Miguel; Martínez-Mora, Juan A.; Bou-Cabo, Manuel; Larosa, Giuseppina; Adrián-Martínez, Silvia; Llorens, Carlos D.

    2012-01-01

    In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to achieve the proposed aim. The developed compact array has practical features such as easy manageability and operation. The prototype designs and the results of different tests are described. The techniques applied for these two acoustic systems are so powerful and versatile that may be of interest in other marine applications using acoustic transmitters. PMID:22666022

  1. Acoustic transmitters for underwater neutrino telescopes.

    PubMed

    Ardid, Miguel; Martínez-Mora, Juan A; Bou-Cabo, Manuel; Larosa, Giuseppina; Adrián-Martínez, Silvia; Llorens, Carlos D

    2012-01-01

    In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to achieve the proposed aim. The developed compact array has practical features such as easy manageability and operation. The prototype designs and the results of different tests are described. The techniques applied for these two acoustic systems are so powerful and versatile that may be of interest in other marine applications using acoustic transmitters.

  2. School cafeteria noise-The impact of room acoustics and speech intelligibility on children's voice levels

    NASA Astrophysics Data System (ADS)

    Bridger, Joseph F.

    2002-05-01

    The impact of room acoustics and speech intelligibility conditions of different school cafeterias on the voice levels of children is examined. Methods of evaluating cafeteria designs and predicting noise levels are discussed. Children are shown to modify their voice levels with changes in speech intelligibility like adults. Reverberation and signal to noise ratio are the important acoustical factors affecting speech intelligibility. Children have much more difficulty than adults in conditions where noise and reverberation are present. To evaluate the relationship of voice level and speech intelligibility, a database of real sound levels and room acoustics data was generated from measurements and data recorded during visits to a variety of existing cafeterias under different occupancy conditions. The effects of speech intelligibility and room acoustics on childrens voice levels are demonstrated. A new method is presented for predicting speech intelligibility conditions and resulting noise levels for the design of new cafeterias and renovation of existing facilities. Measurements are provided for an existing school cafeteria before and after new room acoustics treatments were added. This will be helpful for acousticians, architects, school systems, regulatory agencies, and Parent Teacher Associations to create less noisy cafeteria environments.

  3. Acoustic Design of Naval Structures

    DTIC Science & Technology

    2005-12-01

    Loaded Spring .....................................................124 5.3 Dynamic Vibration Damper ...mounted mechanism and a dynamic vibration damper , with ηa = 0...................129 Figure 5-6. Frequency responses of amplitude of a spring-mounted...mechanism vibrations with a dynamic vibration damper placed on it. .............................................132 Figure 5-7. Dependence of the

  4. Photographic Processing Interpretation Facility Wastewater Conceptual Treatment Design.

    DTIC Science & Technology

    1983-03-01

    COPIES OWY K PO,#D F"-. OiaItA IEO*icAL Iww~~ ioN SkftcE 5W FmkYYAL lOAD SPRMGIELD, VIWIftIA 2]61 REGISTERED WITH Umw1G TEovicAL ltsopmTO C~wnA 9*.D...biological treatment and conventional silver recovery by iron exchanqe or electrolytic regeneration, reverse osmosis (R.O.), ion exchange, and...considered a practical or cost-effective application for the total wa~ta- since the seoaration of the concentrated fix and developer solutions from the

  5. 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 ...

  6. NPL closes acoustics department

    NASA Astrophysics Data System (ADS)

    Extance, Andy

    2016-11-01

    The UK's National Physical Laboratory (NPL) has withdrawn funding for its acoustics, polymer and thermoelectrics groups, triggering concern among airborne acoustics specialists that the move could undermine the country's noise-management policies.

  7. Identifying the 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 ...

  8. Numerical design of RF ablation applicator for hepatic cancer treatment

    NASA Astrophysics Data System (ADS)

    Rakhmadi, Aditya; Basari

    2017-02-01

    Currently, cancer has become one of health problems that is difficult to be overcomed. This disease is not only difficult to be cured, but also to be detected and may cause death. For this reason, RF ablation treatment method is proposed to cure cancer. RF ablation therapy is a method in which an applicator is inserted into the body to kill cancer cells by heating the cells. The cancer cells are exposed to the temperature more than 60°C in short duration (few second to few minutes) so thus cell destruction occurs locally. For the sake of the successful treatment, a minimally invasive method is selected in order for perfect local temperature distribution in cancer cells can be achieved. In this paper, a coax-fed dipole-type applicator with interstitial irradiation technique is proposed aimed at RF ablation into hepatic cells. Numerical simulation is performed to obtain a suitable geometric dimension at operating frequency around 2.45 GHz, in order to localize the ablation area. The proposed applicator is inserted into a simple phantom representing an adult human body model in which normal and cancerous liver cells. The simulated results show that the proposed applicator is able to operate at center frequency of 2.355 GHz with blood droplet-type ablation zone and the temperature around the cancer cell by 60°C can be achieved.

  9. Acoustic emission frequency discrimination

    NASA Technical Reports Server (NTRS)

    Sugg, Frank E. (Inventor); Graham, Lloyd J. (Inventor)

    1988-01-01

    In acoustic emission nondestructive testing, broadband frequency noise is distinguished from narrow banded acoustic emission signals, since the latter are valid events indicative of structural flaws in the material being examined. This is accomplished by separating out those signals which contain frequency components both within and beyond (either above or below) the range of valid acoustic emission events. Application to acoustic emission monitoring during nondestructive bond verification and proof loading of undensified tiles on the Space Shuttle Orbiter is considered.

  10. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2015-07-17

    under-ice scattering , bathymetric diffraction and the application of the ocean acoustic Parabolic Equation to infrasound. 2. Tasks a. Task 1...QSR-14C0172-Ocean Acoustics -063015 Figure 10. Estimated reflection coefficient as a function of frequency by taking the difference of downgoing and...OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics -063015 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics

  11. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2015-10-19

    OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics-093015 Quarterly Progress Report Technical and Financial Deep Water Ocean Acoustics...number. 1. REPORT DATE OCT 2015 2. REPORT TYPE 3. DATES COVERED 01-07-2015 to 30-09-2015 4. TITLE AND SUBTITLE Deep Water Ocean Acoustics...understanding of the impact of the ocean and seafloor environmental variability on deep- water (long-range) ocean acoustic propagation and to develop

  12. Shallow Water Acoustics Studies

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Shallow Water Acoustics Studies James F. Lynch MS #12...N00014-14-1-0040 http://acoustics.whoi.edu/sw06/ LONG TERM GOALS The long term goals of our shallow water acoustics work are to: 1) understand the...nature of low frequency (10-1500 Hz) acoustic propagation, scattering and noise in shallow water when strong oceanic variability is present in the

  13. The acoustics of snoring.

    PubMed

    Pevernagie, Dirk; Aarts, Ronald M; De Meyer, Micheline

    2010-04-01

    Snoring is a prevalent disorder affecting 20-40% of the general population. The mechanism of snoring is vibration of anatomical structures in the pharyngeal airway. Flutter of the soft palate accounts for the harsh aspect of the snoring sound. Natural or drug-induced sleep is required for its appearance. Snoring is subject to many influences such as body position, sleep stage, route of breathing and the presence or absence of sleep-disordered breathing. Its presentation may be variable within or between nights. While snoring is generally perceived as a social nuisance, rating of its noisiness is subjective and, therefore, inconsistent. Objective assessment of snoring is important to evaluate the effect of treatment interventions. Moreover, snoring carries information relating to the site and degree of obstruction of the upper airway. If evidence for monolevel snoring at the site of the soft palate is provided, the patient may benefit from palatal surgery. These considerations have inspired researchers to scrutinize the acoustic characteristics of snoring events. Similarly to speech, snoring is produced in the vocal tract. Because of this analogy, existing techniques for speech analysis have been applied to evaluate snoring sounds. It appears that the pitch of the snoring sound is in the low-frequency range (<500 Hz) and corresponds to a fundamental frequency with associated harmonics. The pitch of snoring is determined by vibration of the soft palate, while nonpalatal snoring is more 'noise-like', and has scattered energy content in the higher spectral sub-bands (>500 Hz). To evaluate acoustic properties of snoring, sleep nasendoscopy is often performed. Recent evidence suggests that the acoustic quality of snoring is markedly different in drug-induced sleep as compared with natural sleep. Most often, palatal surgery alters sound characteristics of snoring, but is no cure for this disorder. It is uncertain whether the perceived improvement after palatal surgery, as

  14. Acoustic Test Results of Melamine Foam with Application to Payload Fairing Acoustic Attenuation Systems

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Anne M.

    2014-01-01

    A spacecraft at launch is subjected to a harsh acoustic and vibration environment resulting from the passage of acoustic energy, created during the liftoff of a launch vehicle, through the vehicle's payload fairing. In order to ensure the mission success of the spacecraft it is often necessary to reduce the resulting internal acoustic sound pressure levels through the usage of acoustic attenuation systems. Melamine foam, lining the interior walls of the payload fairing, is often utilized as the main component of such a system. In order to better understand the acoustic properties of melamine foam, with the goal of developing improved acoustic attenuation systems, NASA has recently performed panel level testing on numerous configurations of melamine foam acoustic treatments at the Riverbank Acoustical Laboratory. Parameters assessed included the foam's thickness and density, as well as the effects of a top outer cover sheet material and mass barriers embedded within the foam. This testing followed the ASTM C423 standard for absorption and the ASTM E90 standard for transmission loss. The acoustic test data obtained and subsequent conclusions are the subjects of this paper.

  15. Advanced Off-Gas Control System Design For Radioactive And Mixed Waste Treatment

    SciTech Connect

    Nick Soelberg

    2005-09-01

    Treatment of radioactive and mixed wastes is often required to destroy or immobilize hazardous constituents, reduce waste volume, and convert the waste to a form suitable for final disposal. These kinds of treatments usually evolve off-gas. Air emission regulations have become increasingly stringent in recent years. Mixed waste thermal treatment in the United States is now generally regulated under the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. These standards impose unprecedented requirements for operation, monitoring and control, and emissions control. Off-gas control technologies and system designs that were satisfactorily proven in mixed waste operation prior to the implementation of new regulatory standards are in some cases no longer suitable in new mixed waste treatment system designs. Some mixed waste treatment facilities have been shut down rather than have excessively restrictive feed rate limits or facility upgrades to comply with the new standards. New mixed waste treatment facilities in the U. S. are being designed to operate in compliance with the HWC MACT standards. Activities have been underway for the past 10 years at the INL and elsewhere to identify, develop, demonstrate, and design technologies for enabling HWC MACT compliance for mixed waste treatment facilities. Some specific off-gas control technologies and system designs have been identified and tested to show that even the stringent HWC MACT standards can be met, while minimizing treatment facility size and cost.

  16. Coding Acoustic Metasurfaces.

    PubMed

    Xie, Boyang; Tang, Kun; Cheng, Hua; Liu, Zhengyou; Chen, Shuqi; Tian, Jianguo

    2017-02-01

    Coding acoustic metasurfaces can combine simple logical bits to acquire sophisticated functions in wave control. The acoustic logical bits can achieve a phase difference of exactly π and a perfect match of the amplitudes for the transmitted waves. By programming the coding sequences, acoustic metasurfaces with various functions, including creating peculiar antenna patterns and waves focusing, have been demonstrated.

  17. Tutorial on architectural acoustics

    NASA Astrophysics Data System (ADS)

    Shaw, Neil; Talaske, Rick; Bistafa, Sylvio

    2002-11-01

    This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).

  18. The citicoline brain injury treatment (COBRIT) trial: design and methods.

    PubMed

    Zafonte, Ross; Friedewald, William T; Lee, Shing M; Levin, Bruce; Diaz-Arrastia, Ramon; Ansel, Beth; Eisenberg, Howard; Timmons, Shelly D; Temkin, Nancy; Novack, Thomas; Ricker, Joseph; Merchant, Randall; Jallo, Jack

    2009-12-01

    Traumatic brain injury (TBI) is a major cause of death and disability. In the United States alone approximately 1.4 million sustain a TBI each year, of which 50,000 people die, and over 200,000 are hospitalized. Despite numerous prior clinical trials no standard pharmacotherapy for the treatment of TBI has been established. Citicoline, a naturally occurring endogenous compound, offers the potential of neuroprotection, neurorecovery, and neurofacilitation to enhance recovery after TBI. Citicoline has a favorable side-effect profile in humans and several meta-analyses suggest a benefit of citicoline treatment in stroke and dementia. COBRIT is a randomized, double-blind, placebo-controlled, multi-center trial of the effects of 90 days of citicoline on functional outcome in patients with complicated mild, moderate, and severe TBI. In all, 1292 patients will be recruited over an estimated 32 months from eight clinical sites with random assignment to citicoline (1000 mg twice a day) or placebo (twice a day), administered enterally or orally. Functional outcomes are assessed at 30, 90, and 180 days after the day of randomization. The primary outcome consists of a set of measures that will be analyzed as a composite measure using a global test procedure at 90 days. The measures comprise the following core battery: the California Verbal Learning Test II; the Controlled Oral Word Association Test; Digit Span; Extended Glasgow Outcome Scale; the Processing Speed Index; Stroop Test part 1 and Stroop Test part 2; and Trail Making Test parts A and B. Secondary outcomes include survival, toxicity, and rate of recovery.

  19. Listening to the acoustics in concert halls

    NASA Astrophysics Data System (ADS)

    Beranek, Leo L.; Griesinger, David

    2001-05-01

    How does acoustics affect the symphonic music performed in a concert hall? The lecture begins with an illustrated discussion of the architectural features that influence the acoustics. Boston Symphony Hall, which was built in 1900 when only one facet of architectural design was known, now rates as one of the world's great halls. How this occurred will be presented. Music is composed with some acoustical environment in mind and this varies with time from the Baroque to the Romantic to the Modern musical period. Conductors vary their interpretation according to the hall they are in. Well-traveled listeners and music critics have favorite halls. The lecture then presents a list of 58 halls rank ordered according to their acoustical quality based on interviews of music critics and conductors. Modern acoustical measurements made in these halls are compared with their rankings. Music recordings will be presented that demonstrate how halls sound that have different measured acoustical parameters. Photographs of a number of recently built halls are shown as examples of how these known acoustical factors have been incorporated into architectural design.

  20. Listening to the acoustics in concert halls

    NASA Astrophysics Data System (ADS)

    Beranek, Leo L.; Griesinger, David

    2004-05-01

    How does acoustics affect the symphonic music performed in a concert hall? The lecture begins with an illustrated discussion of the architectural features that influence the acoustics. Boston Symphony Hall, which was built in 1900 when only one facet of architectural design was known, now rates as one of the world's great halls. How this occurred will be presented. Music is composed with some acoustical environment in mind and this varies with time from the Baroque to the Romantic to the Modern musical period. Conductors vary their interpretation according to the hall they are in. Well-traveled listeners and music critics have favorite halls. The lecture then presents a list of 58 halls rank ordered according to their acoustical quality based on interviews of music critics and conductors. Modern acoustical measurements made in these halls are compared with their rankings. Music recordings will be presented that demonstrate how halls sound that have different measured acoustical parameters. Photographs of a number of recently built halls are shown as examples of how these known acoustical factors have been incorporated into architectural design.

  1. Acoustic focusing by metal circular ring structure

    NASA Astrophysics Data System (ADS)

    Xia, Jian-Ping; Sun, Hong-Xiang

    2015-02-01

    We report an exotic acoustic focusing effect through a simple brass circular ring structure immersed in water. The acoustic waves can be focused on a prefect point at the centre of the ring structure. This exotic acoustic focusing phenomenon arises from the intrinsic modes in the ring structure at some special eigenfrequencies, which is essentially distinct from the previous studies originating from the negative refraction. The focusing effect is closely related to the size and shape of the ring structure. Interesting applications of the focusing mechanism in black box detectors in the sea and medical ultrasound treatment are further discussed.

  2. Principles of Design And Operations Of Wastewater Treatment Pond Systems For Plant Operators, Engineers, And Managers

    EPA Science Inventory

    Wastewater pond systems provide reliable, low cost, and relatively low maintenance treatment for municipal and industrial discharges. However, they do have certain design, operations, and maintenance requirements. While the basic models have not changed in the 30-odd years sinc...

  3. Small Hot Jet Acoustic Rig Validation

    NASA Technical Reports Server (NTRS)

    Brown, Cliff; Bridges, James

    2006-01-01

    The Small Hot Jet Acoustic Rig (SHJAR), located in the Aeroacoustic Propulsion Laboratory (AAPL) at the NASA Glenn Research Center in Cleveland, Ohio, was commissioned in 2001 to test jet noise reduction concepts at low technology readiness levels (TRL 1-3) and develop advanced measurement techniques. The first series of tests on the SHJAR were designed to prove its capabilities and establish the quality of the jet noise data produced. Towards this goal, a methodology was employed dividing all noise sources into three categories: background noise, jet noise, and rig noise. Background noise was directly measured. Jet noise and rig noise were separated by using the distance and velocity scaling properties of jet noise. Effectively, any noise source that did not follow these rules of jet noise was labeled as rig noise. This method led to the identification of a high frequency noise source related to the Reynolds number. Experiments using boundary layer treatment and hot wire probes documented this noise source and its removal, allowing clean testing of low Reynolds number jets. Other tests performed characterized the amplitude and frequency of the valve noise, confirmed the location of the acoustic far field, and documented the background noise levels under several conditions. Finally, a full set of baseline data was acquired. This paper contains the methodology and test results used to verify the quality of the SHJAR rig.

  4. Acoustic cavity technology for high performance injectors

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The feasibility of damping more than one mode of rocket engine combustion instability by means of differently tuned acoustic cavities sharing a common entrance was shown. Analytical procedures and acoustic modeling techniques for predicting the stability behavior of acoustic cavity designs in hot firings were developed. Full scale testing of various common entrance, dual cavity configurations, and subscale testing for the purpose of obtaining motion pictures of the cavity entrance region, to aid in determining the mechanism of cavity damping were the two major aspects of the program.

  5. A novel broadband waterborne acoustic absorber

    NASA Astrophysics Data System (ADS)

    Wang, Changxian; Wen, Weibin; Huang, Yixing; Chen, Mingji; Lei, Hongshuai; Fang, Daining

    2016-07-01

    In this paper, we extended the ray tracing theory in polar coordinate system, and originally proposed the Snell-Descartes law in polar coordinates. Based on these theories, a novel broadband waterborne acoustic absorber device was proposed. This device is designed with gradient-distributing materials along radius, which makes the incidence acoustic wave ray warps. The echo reduction effects of this device were investigated by finite element analysis, and the numerical results show that the reflectivity of acoustic wave for the new device is lower than that of homogenous and Alberich layers in almost all frequency 0-30 kHz at the same loss factor.

  6. Overview of geometrical room acoustic modeling techniques.

    PubMed

    Savioja, Lauri; Svensson, U Peter

    2015-08-01

    Computerized room acoustics modeling has been practiced for almost 50 years up to date. These modeling techniques play an important role in room acoustic design nowadays, often including auralization, but can also help in the construction of virtual environments for such applications as computer games, cognitive research, and training. This overview describes the main principles, landmarks in the development, and state-of-the-art for techniques that are based on geometrical acoustics principles. A focus is given to their capabilities to model the different aspects of sound propagation: specular vs diffuse reflections, and diffraction.

  7. Aero-acoustic design and test of a multiple splitter exhaust noise suppressor for a 0.914m diameter lift fan

    NASA Technical Reports Server (NTRS)

    Stimpert, D. L.

    1973-01-01

    A lift fan exhaust suppression system to meet future VTOL aircraft noise goals was designed and tested. The test vehicle was a 1.3 pressure ratio, 36 inch (91.44 cm) diameter lift fan with two chord rotor to stator spacing. A two splitter fan exhaust suppression system thirty inches (76.2 cm) long achieved 10 PNdB exhaust suppression in the aft quadrant compared to a design value of 20 PNdB. It was found that a broadband noise floor limited the realizable suppression. An analytical investigation of broadband noise generated by flow over the treatment surfaces provided very good agreement with the measured suppression levels and noise floor sound power levels. A fan thrust decrement of 22% was measured for the fully suppressed configuration of which 11.1% was attributed to the exhaust suppression hardware.

  8. Inhaled Formulation Design for the Treatment of Lung Infections.

    PubMed

    Garcia-Contreras, Lucila; Yadav, Khushwant S

    2015-01-01

    Lung infections may be bacterial, viral or fungal and they are typically treated with oral or parenteral antibiotics. Inhaled dry powder formulations offer unique opportunities for treating lung infections with enhanced effectiveness and stability. Since drug delivery to the lungs requires chronic and repeated administration of larger amounts of therapeutics, dry powder formulations are attractive alternatives to deliver drugs directly to the lungs as they are not limited by solubility issues and they are regarded as being more stable than liquid dosage forms. This state-of-the-art review presents the use of inhaled formulations for tuberculosis as a main focus, but also for other diseases such as bronchiectasis, chronic obstructive pulmonary disease (COPD), pneumonia and respiratory infections occurring as complications during lung transplants. Opportunities for the use of inhaled therapies and other respiratory diseases or as prevention or antidotes against warfare agents are offered. Typical and novel inhaled formulations that have been used as well as preclinical and clinical studies and evaluation of these inhaled therapies are discussed for each disease state. Lastly, the use of inhaled therapies as an alternative to end the emergence of drug resistant strains is discussed along with the risks of increasing these resistant strains if the inhaled therapy is not designed based on dosing regimens established by wellplanned pharmacokinetic and pharmacodynamic studies.

  9. What learning theories can teach us in designing neurofeedback treatments.

    PubMed

    Strehl, Ute

    2014-01-01

    Popular definitions of neurofeedback point out that neurofeedback is a process of operant conditioning which leads to self-regulation of brain activity. Self-regulation of brain activity is considered to be a skill. The aim of this paper is to clarify that not only operant conditioning plays a role in the acquisition of this skill. In order to design the learning process additional references have to be derived from classical conditioning, two-process-theory and in particular from skill learning and research into motivational aspects. The impact of learning by trial and error, cueing of behavior, feedback, reinforcement, and knowledge of results as well as transfer of self-regulation skills into everyday life will be analyzed in this paper. In addition to these learning theory basics this paper tries to summarize the knowledge about acquisition of self-regulation from neurofeedback studies with a main emphasis on clinical populations. As a conclusion it is hypothesized that learning to self-regulate has to be offered in a psychotherapeutic, i.e., behavior therapy framework.

  10. Successful Surgical Treatment for Elephantiasis Nostras Verrucosa Using a New Designed Column Flap.

    PubMed

    Han, Hyun Ho; Lim, Soo Yeon; Oh, Deuk Young

    2015-09-01

    Elephantiasis nostras verrucosa is a chronic lymphedema that causes enlarged and disfigured extremities. There are plenty of treatment options. However, there is no complete treatment. Preventive or symptomatic therapy is the basis for treating elephantiasis. In this article, we report a case of elephantiasis nostras verrucosa treated successfully by surgical reconstruction using a newly designed column flap.

  11. Evaluation of Drug Abuse Treatment: A Repeated Measures Design Assessing Methadone Maintenance.

    ERIC Educational Resources Information Center

    Hser, Yih-Ing; And Others

    1988-01-01

    A repeated measures design was used to evaluate methadone maintenance (MM) treatment effects for 720 heroin addicts who entered MM in Southern California in 1971-1978. Compared to pretreatment measures, results show significant improvement for methadone users. Level of improvement was affected by sex, ethnicity, and treatment duration. (TJH)

  12. Acoustic tests of augmentor wing model

    NASA Technical Reports Server (NTRS)

    Goodykoontz, J. H.

    1977-01-01

    Acoustic and aerodynamic data were obtained for a full-scale section of an augmentor wing. Features of the design included a single-row, multielement nozzle array and acoustically tuned panels placed on the interior surfaces of the augmentor. When the data were extrapolated to a 91,000-kilogram aircraft, the calculated sideline perceived noise levels were approximately the same for either the takeoff or approach condition.

  13. A PROTOCOL FOR DETERMINING WWF SETTLING VELOCITIES FOR TREATMENT PROCESS DESIGN ENHANCEMENT

    EPA Science Inventory

    Urban wet weather flows (WWF) contain a high proportion of suspended solids (SS) which must be rapidly reduced before release to receiving waters. Site specific, storm-event data evaluations for designing WWF-treatment facilities differs from dry-weather flow design. WWF-sett...

  14. A Course on Operational Considerations in Wastewater Treatment Plant Design. Instructor's Manual.

    ERIC Educational Resources Information Center

    Cooper, John W.; And Others

    This manual contains 17 instructional units (sequenced to correspond to parallel chapters in a student's manual) focusing on upgrading the design of wastewater plant facilities and serving as a reference source for establishing criteria for upgrading wastewater treatment plants. The manual also furnishes information for modifying plant design to…

  15. PROCESS DESIGN MANUAL: LAND TREATMENT OF MUNICIPAL WASTEWATER. SUPPLEMENT ON RAPID INFILTRATION AND OVERLAND FLOW

    EPA Science Inventory

    The document is intended as a supplement to the 1981 Process Design Manual for Land Treatment of Municipal Wastewater (EPA/625/1-81/013). Throughout the document, the 1981 Manual will be referred to as the Manual. Part I in the text covers design of rapid infiltration systems and...

  16. Rationale, Design, and Methods of the Preschool ADHD Treatment Study (PATS)

    ERIC Educational Resources Information Center

    Kollins, Scott; Greenhill, Laurence; Swanson, James; Wigal, Sharon; Abikoff, Howard; McCracken, James; Riddle, Mark; McGough, James; Vitiello, Benedetto; Wigal, Tim; Skrobala, Anne; Posner, Kelly; Ghuman, Jaswinder; Davies, Mark; Cunningham, Charles; Bauzo, Audrey

    2006-01-01

    Objective: To describe the rationale and design of the Preschool ADHD Treatment Study (PATS). Method: PATS was a National Institutes of Mental Health-funded, multicenter, randomized, efficacy trial designed to evaluate the short-term (5 weeks) efficacy and long-term (40 weeks) safety of methylphenidate (MPH) in preschoolers with…

  17. Preliminary design report for the K basins integrated water treatment system

    SciTech Connect

    Pauly, T.R., Westinghouse Hanford

    1996-08-12

    This Preliminary Design Report (PDR) provides a revised concept for the K Basins Integrated Water Treatment Systems (IWTS). This PDR incorporates the 11 recommendations made in a May 1996 Value Engineering session into the Conceptual Design, and provides new flow diagrams, hazard category assessment, cost estimate, and schedule for the IWTS Subproject.

  18. Rational design of antibiotic treatment plans: a treatment strategy for managing evolution and reversing resistance.

    PubMed

    Mira, Portia M; Crona, Kristina; Greene, Devin; Meza, Juan C; Sturmfels, Bernd; Barlow, Miriam

    2015-01-01

    The development of reliable methods for restoring susceptibility after antibiotic resistance arises has proven elusive. A greater understanding of the relationship between antibiotic administration and the evolution of resistance is key to overcoming this challenge. Here we present a data-driven mathematical approach for developing antibiotic treatment plans that can reverse the evolution of antibiotic resistance determinants. We have generated adaptive landscapes for 16 genotypes of the TEM β-lactamase that vary from the wild type genotype "TEM-1" through all combinations of four amino acid substitutions. We determined the growth rate of each genotype when treated with each of 15 β-lactam antibiotics. By using growth rates as a measure of fitness, we computed the probability of each amino acid substitution in each β-lactam treatment using two different models named the Correlated Probability Model (CPM) and the Equal Probability Model (EPM). We then performed an exhaustive search through the 15 treatments for substitution paths leading from each of the 16 genotypes back to the wild type TEM-1. We identified optimized treatment paths that returned the highest probabilities of selecting for reversions of amino acid substitutions and returning TEM to the wild type state. For the CPM model, the optimized probabilities ranged between 0.6 and 1.0. For the EPM model, the optimized probabilities ranged between 0.38 and 1.0. For cyclical CPM treatment plans in which the starting and ending genotype was the wild type, the probabilities were between 0.62 and 0.7. Overall this study shows that there is promise for reversing the evolution of resistance through antibiotic treatment plans.

  19. Helicopter Acoustics

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Exterior and interior noise problems are addressed both from the physics and engineering as well as the human factors point of view. The role of technology in closing the gap between what the customers and regulating agencies would like to have and what is available is explored. Noise regulation concepts, design, operations and testing for noise control, helicopter noise prediction, and research tools and measurements are among the topics covered.

  20. Advanced Mixed Waste Treatment Project melter system preliminary design technical review meeting

    SciTech Connect

    Eddy, T.L.; Raivo, B.D.; Soelberg, N.R.; Wiersholm, O.

    1995-02-01

    The Idaho National Engineering Laboratory Advanced Mixed Waste Treatment Project sponsored a plasma are melter technical design review meeting to evaluate high-temperature melter system configurations for processing heterogeneous alpha-contaminated low-level radioactive waste (ALLW). Thermal processing experts representing Department of Energy contractors, the Environmental Protection Agency, and private sector companies participated in the review. The participants discussed issues and evaluated alternative configurations for three areas of the melter system design: plasma torch melters and graphite arc melters, offgas treatment options, and overall system configuration considerations. The Technical Advisory Committee for the review concluded that graphite arc melters are preferred over plasma torch melters for processing ALLW. Initiating involvement of stakeholders was considered essential at this stage of the design. For the offgas treatment system, the advisory committee raised the question whether to a use wet-dry or a dry-wet system. The committee recommended that the waste stream characterization, feed preparation, and the control system are essential design tasks for the high-temperature melter treatment system. The participants strongly recommended that a complete melter treatment system be assembled to conduct tests with nonradioactive surrogate waste material. A nonradioactive test bed would allow for inexpensive design and operational changes prior to assembling a system for radioactive waste treatment operations.