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Sample records for acoustic experiments involving

  1. Nonlinear acoustic experiments involving landmine detection: Connections with mesoscopic elasticity and slow dynamics in geomaterials, Part III

    NASA Astrophysics Data System (ADS)

    Korman, Murray S.; Sabatier, James M.

    2005-09-01

    In nonlinear acoustic detection schemes, airborne sound at two primary tones, f1, f2 (closely spaced near an 80-Hz resonance) excites the soil surface over a buried landmine. Due to soil wave interactions with the landmine, a scattered surface profile can be measured by a geophone. Profiles at f1, f2, f1-(f2-f1) and f2+(f2-f1) exhibit single peaks; those at 2f1-(f2-f1), f1+f2 and 2f2+(f2-f1) involve higher order mode shapes for a VS 2.2 plastic, inert, anti-tank landmine, buried at 3.6 cm in sifted loess soil [J. Acoust. Soc. Am. 116, 3354-3369 (2004)]. Near resonance, the bending (softening) of a family of increasing amplitude tuning curves, involving the vibration over the landmine, exhibits a linear relationship between the peak particle velocity and corresponding frequency. Results are similar to nonlinear mesoscopic/nanoscale effects that are observed in granular solids like Berea sandstone. New experiments show that first sweeping up through resonance and then immediately sweeping back down result in different tuning curve behavior that might be explained by ``slow dynamics'' where an effective modulus reduction persists following periods of high strain. Results are similar to those described by TenCate et al. [Phys. Rev. Lett. 85, 1020-1023 (2000)]. [Work supported by U.S. Army RDECOM CERDEC, NVESD.

  2. Experiments on the Acoustics of Whistling.

    ERIC Educational Resources Information Center

    Shadle, Christine H.

    1983-01-01

    The acoustics of speech production allows the prediction of resonances for a given vocal tract configuration. Combining these predictions with aerodynamic theory developed for mechanical whistles makes theories about human whistling more complete. Several experiments involving human whistling are reported which support the theory and indicate new…

  3. Joint Acoustic Propagation Experiment (JAPE)

    NASA Technical Reports Server (NTRS)

    Carnes, Benny L.; Olsen, Robert O.; Kennedy, Bruce W.

    1993-01-01

    The Joint Acoustic Propagation Experiment (JAPE), performed under the auspices of NATO and the Acoustics Working Group, was conducted at White Sands Missile Range, New Mexico, USA, during the period 11-28 Jul. 1991. JAPE consisted of 220 trials using various acoustic sources including speakers, propane cannon, various types of military vehicles, helicopters, a 155mm howitzer, and static high explosives. Of primary importance to the performance of these tests was the intensive characterization of the atmosphere before and during the trials. Because of the wide range of interests on the part of the participants, JAPE was organized in such a manner to provide a broad cross section of test configurations. These included short and long range propagation from fixed and moving vehicles, terrain masking, and vehicle detection. A number of independent trials were also performed by individual participating agencies using the assets available during JAPE. These tests, while not documented in this report, provided substantial and important data to those groups. Perhaps the most significant feature of JAPE is the establishment of a permanent data base which can be used by not only the participants but by others interested in acoustics. A follow-on test was performed by NASA LaRC during the period 19-29 Aug. 1991 at the same location. These trials consisted of 59 overflights of supersonic aircraft in order to establish the relationship between atmospheric turbulence and the received sonic boom energy at the surface.

  4. Acoustic Scattering in Flexible Waveguide Involving Step Discontinuity

    PubMed Central

    Afzal, Muhammad; Nawaz, Rab; Ayub, Muhammad; Wahab, Abdul

    2014-01-01

    In this paper, the propagation and scattering of acoustic waves in a flexible wave-guide involving step discontinuity at an interface is considered. The emerging boundary value problem is non-Sturm-Liouville and is solved by employing a hybrid mode-matching technique. The physical scattering process and attenuation of duct modes versus frequency regime and change of height is studied. Moreover, the mode-matching solution is validated through a series of numerical experiments by testifying the power conservation identity and matching interface conditions. PMID:25084019

  5. Joint Acoustic Propagation Experiment (JAPE-91) Workshop

    NASA Technical Reports Server (NTRS)

    Willshire, William L., Jr. (Compiler); Chestnutt, David (Compiler)

    1993-01-01

    The Joint Acoustic Propagation Experiment (JAPE), was conducted at the White Sands Missile Range, New Mexico, USA, during the period 11-28 Jul. 1991. JAPE consisted of various short and long range propagation experiments using various acoustic sources including speakers, propane cannons, helicopters, a 155 mm howitzer, and static high explosives. Of primary importance to the performance of theses tests was the extensive characterization of the atmosphere during these tests. This atmospheric characterization included turbulence measurements. A workshop to disseminate the results of JAPE-91 was held in Hampton, VA, on 28 Apr. 1993. This report is a compilation of the presentations made at the workshop along with a list of attendees and the agenda.

  6. Vehicular sources in acoustic propagation experiments

    NASA Technical Reports Server (NTRS)

    Prado, Gervasio; Fitzgerald, James; Arruda, Anthony; Parides, George

    1990-01-01

    One of the most important uses of acoustic propagation models lies in the area of detection and tracking of vehicles. Propagation models are used to compute transmission losses in performance prediction models and to analyze the results of past experiments. Vehicles can also provide the means for cost effective experiments to measure acoustic propagation conditions over significant ranges. In order to properly correlate the information provided by the experimental data and the propagation models, the following issues must be taken into consideration: the phenomenology of the vehicle noise sources must be understood and characterized; the vehicle's location or 'ground truth' must be accurately reproduced and synchronized with the acoustic data; and sufficient meteorological data must be collected to support the requirements of the propagation models. The experimental procedures and instrumentation needed to carry out propagation experiments are discussed. Illustrative results are presented for two cases. First, a helicopter was used to measure propagation losses at a range of 1 to 10 Km. Second, a heavy diesel-powered vehicle was used to measure propagation losses in the 300 to 2200 m range.

  7. Radiosurgery for acoustic neurinomas: Early experience

    SciTech Connect

    Linskey, M.E.; Lunsford, L.D.; Flickinger, J.C. )

    1990-05-01

    We reviewed our early experience with the first 26 patients with acoustic neurinomas (21 unilateral, 5 bilateral) treated by stereotactic radiosurgery using the first North American 201-source cobalt-60 gamma knife. Follow-up ranged from 6 to 19 months (median, 13 months). Serial postoperative imaging showed either a decrease in tumor size (11 patients) or growth arrest (15 patients). Loss of central contrast enhancement was a characteristic change (18 patients). Seven patients had good or serviceable hearing preoperatively. In all 7 the preoperative hearing status was retained immediately after radiosurgery. At follow-up, 3 had preserved hearing, 1 had reduced hearing, and 3 had lost all hearing in the treated ear. Hearing in 1 patient that was nonserviceable preoperatively later improved to a serviceable hearing level. Delayed facial paresis developed in 6 patients, and delayed trigeminal sensory loss developed in 7 patients, none of whom had significant deficits before radiosurgery. Both facial and trigeminal deficits tended to improve within 3 to 6 months of onset with excellent recovery anticipated. Lower cranial nerve dysfunction was not observed. All 26 patients remain at their preoperative employment or functional status. At present, stereotactic radiosurgery is an alternative treatment for acoustic neurinomas in patients who are elderly, have significant concomitant medical problems, have a tumor in their only hearing ear, have bilateral acoustic neurinomas, refuse microsurgical excision, or have recurrent tumor despite surgical resection. Although longer and more extensive follow-up is required, the control of tumor growth and the acceptable rate of complications in this early experience testifies to the future expanding role of this technique in the management of selected acoustic neurinomas.

  8. Effects of Previous Acoustic Experience on Behavioral Responses to Experimental Sound Stimuli and Implications for Research.

    PubMed

    Voellmy, Irene K; Purser, Julia; Simpson, Stephen D; Radford, Andrew N

    2016-01-01

    Ambient noise differs considerably between habitats. Increased ambient noise can affect the physiology and behavior in a variety of taxa. Previous acoustic experience can modify behavior and potentially affect research conclusions in natural and laboratory environments. Acoustic conditions should thus be accounted for, especially in experiments involving experimental sound stimuli. Methods sections should contain acoustic specifications, and a consensus should be achieved over which measurements to include for comparability between researchers. Further investigation of how previous and repeated exposure to sound affects behavior and research conclusions is needed to improve our knowledge of acoustic long-term effects in animal welfare and conservation.

  9. The North Pacific Acoustic Laboratory deep-water acoustic propagation experiments in the Philippine Sea.

    PubMed

    Worcester, Peter F; Dzieciuch, Matthew A; Mercer, James A; Andrew, Rex K; Dushaw, Brian D; Baggeroer, Arthur B; Heaney, Kevin D; D'Spain, Gerald L; Colosi, John A; Stephen, Ralph A; Kemp, John N; Howe, Bruce M; Van Uffelen, Lora J; Wage, Kathleen E

    2013-10-01

    A series of experiments conducted in the Philippine Sea during 2009-2011 investigated deep-water acoustic propagation and ambient noise in this oceanographically and geologically complex region: (i) the 2009 North Pacific Acoustic Laboratory (NPAL) Pilot Study/Engineering Test, (ii) the 2010-2011 NPAL Philippine Sea Experiment, and (iii) the Ocean Bottom Seismometer Augmentation of the 2010-2011 NPAL Philippine Sea Experiment. The experimental goals included (a) understanding the impacts of fronts, eddies, and internal tides on acoustic propagation, (b) determining whether acoustic methods, together with other measurements and ocean modeling, can yield estimates of the time-evolving ocean state useful for making improved acoustic predictions, (c) improving our understanding of the physics of scattering by internal waves and spice, (d) characterizing the depth dependence and temporal variability of ambient noise, and (e) understanding the relationship between the acoustic field in the water column and the seismic field in the seafloor. In these experiments, moored and ship-suspended low-frequency acoustic sources transmitted to a newly developed distributed vertical line array receiver capable of spanning the water column in the deep ocean. The acoustic transmissions and ambient noise were also recorded by a towed hydrophone array, by acoustic Seagliders, and by ocean bottom seismometers.

  10. Canada Basin Acoustic Propagation Experiment (CANAPE)

    DTIC Science & Technology

    2015-09-30

    the ocean from wind and solar forcing and preserving the stable Arctic acoustic channel. Ice conditions are not the only environmental changes in...measurements: • Temperature and salinity from Sea- Bird MicroCATs and Temperature Recorders on the DVLA and the acoustic transceiver moorings (J. Colosi

  11. 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…

  12. Intermedius nerve involvement and testing in acoustic neuromas.

    PubMed

    Thomsen, J; Zilstorff, K

    1975-01-01

    The clinical findings in 125 patients with surgically confirmed acoustic neuromas are presented, with special regard to the involvement of the intermedius nerve in the diagnosis. In assessing the function of the intermedius nerve the examination of the nasolacrimal reflex and the sensation of taste on the anterior two-thirds of the tongue are used. The methods of investigation are described in detail. The material consisted of 20 medium-sized and 105 large tumours; no intracanalicular tumor was found. Hearing loss was the initial symptom in 85% of the patients, 10% had tinitus and 4% vertigo as the first symptom. Apart from the VIII cranial nerve symptoms, a defective nasolacrimal reflex was the most significant evidence of cerebellopontine angle pathology. The test was positive in 65% of the medium-sized tumours, in the entire material, 85%. The figures are higher than the incidence of trigeminal nerve symptoms. This in contrast to the reports of most authors. The tests described are simple and quick to perform, and it is emphasized that they should be applied to all patients with unilateral hearing loss of unknown origin.

  13. Acoustical experiment of yogurt fermentation process.

    PubMed

    Ogasawara, H; Mizutani, K; Ohbuchi, T; Nakamura, T

    2006-12-22

    One of the important factors through food manufacturing is hygienic management. Thus, food manufactures prove their hygienic activities by taking certifications like a Hazard Analysis and Critical Control Point (HACCP). This concept also applies to food monitoring. Acoustical measurements have advantage for other measurement in food monitoring because they make it possible to measure with noncontact and nondestructive. We tried to monitor lactic fermentation of yogurt by a probing sensor using a pair of acoustic transducers. Temperature of the solution changes by the reaction heat of fermentation. Consequently the sound velocity propagated through the solution also changes depending on the temperature. At the same time, the solution change its phase from liquid to gel. The transducers usage in the solution indicates the change of the temperature as the change of the phase difference between two transducers. The acoustic method has advantages of nondestructive measurement that reduces contamination of food product by measuring instrument. The sensor was inserted into milk with lactic acid bacterial stain of 19 degrees C and monitored phase retardation of propagated acoustic wave and its temperature with thermocouples in the mild. The monitoring result of fermentation from milk to Caspian Sea yogurt by the acoustic transducers with the frequency of 3.7 MHz started to show gradient change in temperature caused by reaction heat of fermentation but stop the gradient change at the end although the temperature still change. The gradient change stopped its change because of phase change from liquid to gel. The present method will be able to measure indirectly by setting transducers outside of the measuring object. This noncontact sensing method will have great advantage of reduces risk of food contamination from measuring instrument because the measurement probes are set out of fermentation reactor or food containers. Our proposed method will contribute to the

  14. 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

  15. Analysis of passive acoustic ranging of helicopters from the joint acoustic propagation experiment

    NASA Technical Reports Server (NTRS)

    Carnes, Benny L.; Morgan, John C.

    1993-01-01

    For more than twenty years, personnel of the U.S.A.E. Waterways Experiment Station (WES) have been performing research dealing with the application of sensors for detection of military targets. The WES research has included the use of seismic, acoustic, magnetic, and other sensors to detect, track, and classify military ground targets. Most of the WES research has been oriented toward the employment of such sensors in a passive mode. Techniques for passive detection are of particular interest in the Army because of the advantages over active detection. Passive detection methods are not susceptible to interception, detection, jamming, or location of the source by the threat. A decided advantage for using acoustic and seismic sensors for detection in tactical situations is the non-line-of-sight capability; i.e., detection of low flying helicopters at long distances without visual contact. This study was conducted to analyze the passive acoustic ranging (PAR) concept using a more extensive data set from the Joint Acoustic Propagation Experiment (JAPE).

  16. 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.

  17. Acoustic emissions in rock deformation experiments under micro-CT

    NASA Astrophysics Data System (ADS)

    Tisato, Nicola; Goodfellow, Sebastian D.; Moulas, Evangelos; Di Toro, Giulio; Young, Paul; Grasselli, Giovanni

    2016-04-01

    The study of acoustic emissions (AE) generated by rocks undergoing deformation has become, in the last decades, one of the most powerful tools for boosting our understanding of the mechanisms which are responsible for rock failures. AE are elastic waves emitted by the local failure of micro- or milli-metric portions of the tested specimen. At the same time, X-ray micro computed tomography (micro-CT) has become an affordable, reliable and powerful tool for imaging the internal structure of rock samples. In particular, micro-CT coupled with a deformation apparatus offers the unique opportunity for observing, without perturbing, the sample while the deformation and the formation of internal structures, such as shear bands, is ongoing. Here we present some preliminary results gathered with an innovative apparatus formed by the X-ray transparent pressure vessel called ERDμ equipped with AE sensors, an AE acquisition system and a micro-CT apparatus available at the University of Toronto. The experiment was performed on a 12 mm diameter 36 mm long porous glass sample which was cut on a 60 deg inclined plane (i.e. saw-cut sample). Etna basaltic sand with size ~1 mm was placed between the two inclined faces forming an inclined fault zone with ~2 mm thickness. The sample assembly was jacketed with a polyefin shrink tube and two AE sensors were glued onto the glass samples above and below the fault zone. The sample was then enclosed in the pressure vessel and confined with compressed air up to 3 MPa. A third AE sensor was placed outside the vessel. The sample was saturated with water and AE were generated by varying the fluid and confining pressure or the vertical force, causing deformations concentrated in the fault zone. Mechanical data and AE traces were collected throughout the entire experiment which lasted ~24 hours. At the same time multiple micro-CT 3D datasets and 2D movie-radiographies were collected, allowing the 3D reconstruction of the deformed sample at

  18. Acoustic processing method for MS/MS experiments

    NASA Technical Reports Server (NTRS)

    Whymark, R. R.

    1973-01-01

    Acoustical methods in which intense sound beams can be used to control the position of objects are considered. The position control arises from the radiation force experienced when a body is placed in a sound field. A description of the special properties of intense sound fields useful for position control is followed by a discussion of the more obvious methods of position, namely the use of multiple sound beams. A new type of acoustic position control device is reported that has advantages of simplicity and reliability and utilizes only a single sound beam. Finally a description is given of an experimental single beam levitator, and the results obtained in a number of key levitation experiments.

  19. Theory and experiment research of two-dimension acoustic metamaterial

    NASA Astrophysics Data System (ADS)

    Sun, Hongwei; Li, JianFeng; Li, Zhiming; Li, Ying

    2013-04-01

    This paper presents modeling and analysis methods for design of a acoustic metamaterial panel consisting of two isotropic plates and small membrane-mass subsystems for absorption of low frequencies transverse elastic waves. Two models of a unit cell are derived and used to demonstrate the existence of negative effective material properties. Moreover, the design of experiment sample confirms that the model and analysis methods are valid. (1) The frequency of the membrane-mass subsystems are uniform distribution in whole acoustic metamaterial panel have two vibration models. (2) The different distributions of membrane-mass subsystems and their resonance frequencies result in different vibration isolation characteristics. (3) PSV is used to test and the result show that a low frequency wave absorber does not require nano-manufacturing techniques. (4) If we design the frequency of the membrane-mass subsystems different it can change the character of the metamaterial panel.

  20. Device for acoustic pulse echo experiments in the subterahertz range

    NASA Astrophysics Data System (ADS)

    Legrand, R.; Huynh, A.; Vincent, S.; Perrin, B.; Lemaître, A.

    2017-01-01

    We present experimental results on the light-to-sound transduction by a superlattice embedded in an optical microcavity, using picosecond ultrasonics. Experiments on the ability to generate and detect phonons at 0.3 and 0.6 THz were performed at low temperature. Finally, we demonstrate that such a device can detect the acoustic burst that it has generated and which has propagated through the substrate, been reflected on the backside of the substrate, and has returned to the device. We study the efficiency of this detection by varying independently the laser wavelength of the pump and probe, by means of asynchronous optical sampling.

  1. An Acoustic Demonstration Model for CW and Pulsed Spectrosocopy Experiments

    NASA Astrophysics Data System (ADS)

    Starck, Torben; Mäder, Heinrich; Trueman, Trevor; Jäger, Wolfgang

    2009-06-01

    High school and undergraduate students have often difficulties if new concepts are introduced in their physics or chemistry lectures. Lecture demonstrations and references to more familiar analogues can be of great help to the students in such situations. We have developed an experimental setup to demonstrate the principles of cw absorption and pulsed excitation - emission spectroscopies, using acoustical analogues. Our radiation source is a speaker and the detector is a microphone, both controlled by a computer sound card. The acoustical setup is housed in a plexiglas box, which serves as a resonator. It turns out that beer glasses are suitable samples; this also helps to keep the students interested! The instrument is controlled by a LabView program. In a cw experiment, the sound frequency is swept through a certain frequency range and the microphone response is recorded simultaneously as function of frequency. A background signal without sample is recorded, and background subtraction yields the beer glass spectrum. In a pulsed experiment, a short sound pulse is generated and the microphone is used to record the resulting emission signal of the beer glass. A Fourier transformation of the time domain signal gives then the spectrum. We will discuss the experimental setup and show videos of the experiments.

  2. Parametric Acoustic Receiving Array (Parray) Research and Experiments.

    DTIC Science & Technology

    1980-02-06

    AD-AC83 704 TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS FIG 17/1 PARAMETRIC ACOUSTIC RECEIVING ARRAY ( PARRAY ) RESEARCH AND EXPER-CTC(U) FEB 80 T G...TITLE anld Subtitle) ,__t, I -1rilUl tT :. 40441" ,APT19* .... ,. L PARAMETRIC ACOUSTIC RECEIVING ARRAY ( PARRAY ) inal technical re. m , LIESEARCH AND...WORDS (Continue on reverse side it necaesary and Identify by block number) PARRAY parametric acoustic receiver nonlinear acoustics parametric acoustic

  3. Array Receivers and Sound Sources for Three Dimensional Shallow Water Acoustic Field Experiments

    DTIC Science & Technology

    2016-12-06

    Water Acoustic Field Experiments NOOO 14-15-1-2893 Sc. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Sd. PROJECT NUMBER Ying Tsong-Lin 132893SP Se. TASK...testing. 1S. SUBJECT TERMS acoustics, shallow water , Arctic Ocean , 3-D acoustic propagation, shelfbreak 16. SECURITY CLASSIFICATION OF: R b...Approved f or public release; distribution is unlimited. Array Receivers and Sound Sources for Three-Dimensional Shallow- Water Acoustic Field

  4. Oscillating load-induced acoustic emission in laboratory experiment

    USGS Publications Warehouse

    Ponomarev, Alexander; Lockner, David A.; Stroganova, S.; Stanchits, S.; Smirnov, V.

    2010-01-01

    Spatial and temporal patterns of acoustic emission (AE) were studied. A pre-fractured cylinder of granite was loaded in a triaxial machine at 160 MPa confining pressure until stick-slip events occurred. The experiments were conducted at a constant strain rate of 10−7 s−1 that was modulated by small-amplitude sinusoidal oscillations with periods of 175 and 570 seconds. Amplitude of the oscillations was a few percent of the total load and was intended to simulate periodic loading observed in nature (e.g., earth tides or other sources). An ultrasonic acquisition system with 13 piezosensors recorded acoustic emissions that were generated during deformation of the sample. We observed a correlation between AE response and sinusoidal loading. The effect was more pronounced for higher frequency of the modulating force. A time-space spectral analysis for a “point” process was used to investigate details of the periodic AE components. The main result of the study was the correlation of oscillations of acoustic activity synchronized with the applied oscillating load. The intensity of the correlated AE activity was most pronounced in the “aftershock” sequences that followed large-amplitude AE events. We suggest that this is due to the higher strain-sensitivity of the failure area when the sample is in a transient, unstable mode. We also found that the synchronization of AE activity with the oscillating external load nearly disappeared in the period immediately after the stick-slip events and gradually recovered with further loading.

  5. Student Microwave Experiments Involving the Doppler Effect.

    ERIC Educational Resources Information Center

    Weber, F. Neff; And Others

    1980-01-01

    Described is the use of the Doppler Effect with microwaves in the measurement of the acceleration due to gravity of falling objects. The experiments described add to the repertoire of quantitative student microwave experiments. (Author/DS)

  6. Acoustic emissions verification testing of International Space Station experiment racks at the NASA Glenn Research Center Acoustical Testing Laboratory

    NASA Astrophysics Data System (ADS)

    Akers, James C.; Passe, Paul J.; Cooper, Beth A.

    2005-09-01

    The Acoustical Testing Laboratory (ATL) at the NASA John H. Glenn Research Center (GRC) in Cleveland, OH, provides acoustic emission testing and noise control engineering services for a variety of specialized customers, particularly developers of equipment and science experiments manifested for NASA's manned space missions. The ATL's primary customer has been the Fluids and Combustion Facility (FCF), a multirack microgravity research facility being developed at GRC for the USA Laboratory Module of the International Space Station (ISS). Since opening in September 2000, ATL has conducted acoustic emission testing of components, subassemblies, and partially populated FCF engineering model racks. The culmination of this effort has been the acoustic emission verification tests on the FCF Combustion Integrated Rack (CIR) and Fluids Integrated Rack (FIR), employing a procedure that incorporates ISO 11201 (``Acoustics-Noise emitted by machinery and equipment-Measurement of emission sound pressure levels at a work station and at other specified positions-Engineering method in an essentially free field over a reflecting plane''). This paper will provide an overview of the test methodology, software, and hardware developed to perform the acoustic emission verification tests on the CIR and FIR flight racks and lessons learned from these tests.

  7. Sperm whale predator-prey interactions involve chasing and buzzing, but no acoustic stunning

    PubMed Central

    Fais, A.; Johnson, M.; Wilson, M.; Aguilar Soto, N.; Madsen, P. T.

    2016-01-01

    The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. Several hypotheses have been advanced to propose both active and passive means to acquire prey, including acoustic debilitation of prey with very powerful clicks. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts. We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1–2 orders of magnitude. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate prey capture. Rather, buzzing involves high-frequency, low amplitude clicks well suited to provide high-resolution biosonar updates during the last stages of capture. The high temporal resolution helps to guide motor patterns during occasionally prolonged chases in which prey are eventually subdued with the aid of fast jaw movements and/or buccal suction as indicated by acceleration transients (jerks) near the end of buzzes. PMID:27340122

  8. Long range acoustic imaging of the continental shelf environment: the Acoustic Clutter Reconnaissance Experiment 2001.

    PubMed

    Ratilal, Purnima; Lai, Yisan; Symonds, Deanelle T; Ruhlmann, Lilimar A; Preston, John R; Scheer, Edward K; Garr, Michael T; Holland, Charles W; Goff, John A; Makris, Nicholas C

    2005-04-01

    An active sonar system is used to image wide areas of the continental shelf environment by long-range echo sounding at low frequency. The bistatic system, deployed in the STRATAFORM area south of Long Island in April-May of 2001, imaged a large number of prominent clutter events over ranges spanning tens of kilometers in near real time. Roughly 3000 waveforms were transmitted into the water column. Wide-area acoustic images of the ocean environment were generated in near real time for each transmission. Between roughly 10 to more than 100 discrete and localized scatterers were registered for each image. This amounts to a total of at least 30000 scattering events that could be confused with those from submerged vehicles over the period of the experiment. Bathymetric relief in the STRATAFORM area is extremely benign, with slopes typically less than 0.5 degrees according to high resolution (30 m sampled) bathymetric data. Most of the clutter occurs in regions where the bathymetry is locally level and does not coregister with seafloor features. No statistically significant difference is found in the frequency of occurrence per unit area of repeatable clutter inside versus outside of areas occupied by subsurface river channels.

  9. Acoustic interactions between an altitude test facility and jet engine plumes: Theory and experiments

    NASA Technical Reports Server (NTRS)

    Ahuja, K. K.; Jones, R. R., III; Tam, C. K.; Massey, K. C.; Fleming, A. J.

    1992-01-01

    The overall objective of the described effort was to develop an understanding of the physical mechanisms involved in the flow/acoustic interactions experienced in full-scale altitude engine test facilities. This is done by conducting subscale experiments and through development of a theoretical model. Model cold jet experiments with an axisymmetric convergent nozzle are performed in a test setup that stimulates a supersonic jet exhausting into a cylindrical diffuser. The measured data consist of detailed flow visualization data and acoustic spectra for a free and a ducted plume. It is shown that duct resonance is most likely responsible by theoretical calculations. Theoretical calculations also indicate that the higher discrete tones observed in the measurements are related to the screech phenomena. Limited experiments on the sensitivity of a free 2-D, C-D nozzle to externally imposed sound are also presented. It is shown that a 2-D, C-D nozzle with a cutback is less excitable than a 2-D C-D nozzle with no cutback. At a pressure ratio of 1.5 unsteady separation from the diverging walls of the nozzle is noticed. This separation switches from one wall to the opposite wall thus providing an unsteady deflection of the plume. It is shown that this phenomenon is related to the venting provided by the cutback section.

  10. Recent Experiments Involving Few-Nucleon Systems

    NASA Astrophysics Data System (ADS)

    Tornow, W.

    2014-08-01

    Recent experimental results are presented for reactions involving A = 3 to A = 6 nuclear systems. The emphasis is on unique data obtained at new experimental facilities. It is shown that the inertial confinement fusion facilities OMEGA and NIF provide a largely unexpected opportunity for experimental few-body physics to both obtain data of unprecedented quality and extend previous measurements to energies not accessible in the past. Whenever possible, data are compared to state-of-the-art theoretical calculations.

  11. Physical oceanography and acoustic propagation during LADC experiment in the Gulf of Mexico in 2001

    NASA Astrophysics Data System (ADS)

    Vinogradov, Sergey; Caruthers, Jerald W.; Rayborn, Grayson H.; Udovydchenkov, Ilya A.; Sidorovskaia, Natalia A.; Rypina, Irina I.; Newcomb, Joal J.; Fisher, Robert A.; Ioup, George E.; Ioup, Juliette W.

    2003-04-01

    The Littoral Acoustic Demonstration Center (LADC) deployed three environmental and acoustic moorings in a downslope line just off the Mississippi River Delta in the northern Gulf of Mexico in an area of a large concentration of sperm whales in July 2001. The measurement of whale vocalizations and, more generally, ambient noise, were the objectives of the experiment. Each mooring had a single hydrophone autonomously recording Environmental Acoustic Recording System (EARS) obtained from the U.S. Naval Oceanographic Office and modified to recorded signals up to 5859 Hz continuously for 36 days. Also, self-recording, environmental sensors were attached to the moorings to obtain profiles of time series data of temperature and salinity. Satellite imagery and NOAA mooring data were gathered for an analysis of eddy formations and movement in the Gulf. This paper will discuss the possible environmental impact of two events that occurred during the experiment: the passage of Tropical Storm Barry and the movement of the remnants of an eddy in the area. Discussed also will be the expected effects of these events on acoustic propagation based on modeling, which are carried out for long range and low frequency (300 km and 500 Hz) using the normal-mode acoustic model SWAMP (Shallow Water Acoustic Modal Propagation by M. F. Werby and N. A. Sidorovskaia) and for short range and high frequency (10 km and 5000 Hz) using the parabolic-equation acoustic model RAM (Range-dependent Acoustic model by M. Collins). [Work supported by ONR.

  12. NATO TG-53: acoustic detection of weapon firing joint field experiment

    NASA Astrophysics Data System (ADS)

    Robertson, Dale N.; Pham, Tien; Scanlon, Michael V.; Srour, Nassy; Reiff, Christian G.; Sim, Leng K.; Solomon, Latasha; Thompson, Dorothea F.

    2006-05-01

    In this paper, we discuss the NATO Task Group 53 (TG-53) acoustic detection of weapon firing field joint experiment at Yuma Proving Ground during 31 October to 4 November 2005. The participating NATO countries include France, the Netherlands, UK and US. The objectives of the joint experiments are: (i) to collect acoustic signatures of direct and indirect firings from weapons such as sniper, mortar, artillery and C4 explosives and (ii) to share signatures among NATO partners from a variety of acoustic sensing platforms on the ground and in the air distributed over a wide area.

  13. Ray dynamics in a long-range acoustic propagation experiment

    NASA Astrophysics Data System (ADS)

    Beron-Vera, Francisco J.; Brown, Michael G.; Colosi, John A.; Tomsovic, Steven; Virovlyansky, Anatoly L.; Wolfson, Michael A.; Zaslavsky, George M.

    2003-09-01

    A ray-based wave-field description is employed in the interpretation of broadband basin-scale acoustic propagation measurements obtained during the Acoustic Thermometry of Ocean Climate program's 1994 Acoustic Engineering Test. Acoustic observables of interest are wavefront time spread, probability density function (PDF) of intensity, vertical extension of acoustic energy in the reception finale, and the transition region between temporally resolved and unresolved wavefronts. Ray-based numerical simulation results that include both mesoscale and internal-wave-induced sound-speed perturbations are shown to be consistent with measurements of all the aforementioned observables, even though the underlying ray trajectories are predominantly chaotic, that is, exponentially sensitive to initial and environmental conditions. Much of the analysis exploits results that relate to the subject of ray chaos; these results follow from the Hamiltonian structure of the ray equations. Further, it is shown that the collection of the many eigenrays that form one of the resolved arrivals is nonlocal, both spatially and as a function of launch angle, which places severe restrictions on theories that are based on a perturbation expansion about a background ray.

  14. Ray dynamics in a long-range acoustic propagation experiment.

    PubMed

    Beron-Vera, Francisco J; Brown, Michael G; Colosi, John A; Tomsovic, Steven; Virovlyansky, Anatoly L; Wolfson, Michael A; Zaslavsky, George M

    2003-09-01

    A ray-based wave-field description is employed in the interpretation of broadband basin-scale acoustic propagation measurements obtained during the Acoustic Thermometry of Ocean Climate program's 1994 Acoustic Engineering Test. Acoustic observables of interest are wavefront time spread, probability density function (PDF) of intensity, vertical extension of acoustic energy in the reception finale, and the transition region between temporally resolved and unresolved wavefronts. Ray-based numerical simulation results that include both mesoscale and internal-wave-induced sound-speed perturbations are shown to be consistent with measurements of all the aforementioned observables, even though the underlying ray trajectories are predominantly chaotic, that is, exponentially sensitive to initial and environmental conditions. Much of the analysis exploits results that relate to the subject of ray chaos; these results follow from the Hamiltonian structure of the ray equations. Further, it is shown that the collection of the many eigenrays that form one of the resolved arrivals is nonlocal, both spatially and as a function of launch angle, which places severe restrictions on theories that are based on a perturbation expansion about a background ray.

  15. Quantitative Analysis Of Acoustic Emission From Rock Fracture Experiments

    NASA Astrophysics Data System (ADS)

    Goodfellow, Sebastian David

    This thesis aims to advance the methods of quantitative acoustic emission (AE) analysis by calibrating sensors, characterizing sources, and applying the results to solve engi- neering problems. In the first part of this thesis, we built a calibration apparatus and successfully calibrated two commercial AE sensors. The ErgoTech sensor was found to have broadband velocity sensitivity and the Panametrics V103 was sensitive to surface normal displacement. These calibration results were applied to two AE data sets from rock fracture experiments in order to characterize the sources of AE events. The first data set was from an in situ rock fracture experiment conducted at the Underground Research Laboratory (URL). The Mine-By experiment was a large scale excavation response test where both AE (10 kHz - 1 MHz) and microseismicity (MS) (1 Hz - 10 kHz) were monitored. Using the calibration information, magnitude, stress drop, dimension and energy were successfully estimated for 21 AE events recorded in the tensile region of the tunnel wall. Magnitudes were in the range -7.5 < Mw < -6.8, which is consistent with other laboratory AE results, and stress drops were within the range commonly observed for induced seismicity in the field (0.1 - 10 MPa). The second data set was AE collected during a true-triaxial deformation experiment, where the objectives were to characterize laboratory AE sources and identify issues related to moving the analysis from ideal in situ conditions to more complex laboratory conditions in terms of the ability to conduct quantitative AE analysis. We found AE magnitudes in the range -7.8 < Mw < -6.7 and as with the in situ data, stress release was within the expected range of 0.1 - 10 MPa. We identified four major challenges to quantitative analysis in the laboratory, which in- hibited our ability to study parameter scaling (M0 ∝ fc -3 scaling). These challenges were 0c (1) limited knowledge of attenuation which we proved was continuously evolving, (2

  16. Basin Acoustic Seamount Scattering Experiment (BASSEX) Data Analysis and Modeling

    DTIC Science & Technology

    2016-06-07

    Kauai source at various ranges and bearings . OBJECTIVES The primary objective of this work is to measure aspects of acoustic propagation that...horizontal plane, arriving at the array from a different bearing . Further analysis will include processing all of the BASSEX KNPAL receptions and

  17. Construction of an anechoic chamber for aeroacoustic experiments and examination of its acoustic parameters

    NASA Astrophysics Data System (ADS)

    Kopiev, V. F.; Palchikovskiy, V. V.; Belyaev, I. V.; Bersenev, Yu. V.; Makashov, S. Yu.; Khramtsov, I. V.; Korin, I. A.; Sorokin, E. V.; Kustov, O. Yu.

    2017-01-01

    The acoustic parameters of a new anechoic chamber constructed at Perm National Research Polytechnic University (PNRPU) are presented. This chamber is designed to be used, among other things, for measuring noise from aerodynamic sources. Sound-absorbing wedges lining the walls of the chamber were studied in an interferometer with normal wave incidence. The results are compared to the characteristics of sound-absorbing wedges of existing anechoic facilities. Metrological examination of the acoustic parameters of the PNRPU anechoic chamber demonstrates that free field conditions are established in it, which will make it possible to conduct quantitative acoustic experiments.

  18. 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).

  19. Shipboard Acoustic Current Profiling during the Coastal Ocean Dynamics Experiment,

    DTIC Science & Technology

    1985-05-01

    Fig. 2.2 Range Gated Shipboard Doppler System . Four beams (fore. aft. port ard starboard) equally inclined from the ship’s vertical axis acousticallN...sarne cannot be said, however, for other beam geometries, such as the three-bean Jlanus system . M\\oreover. the effects, of finite beam width. side... System . Four beams (fore, aft, port and Sstarboard) equally inclined from the ship’s vertical axis acoustically probe the ocean. The Doppler shift in

  20. San Clemente Island Undersea Range Acoustic Experiment, July 2002

    DTIC Science & Technology

    2006-05-31

    sonic amplifier, FM modulator, VHF transmitter, and antenna (see Figure 15). Ocean acoustic pressure waves create movement in the sonobuoy hydrophone...The hydrophone creates a resultant voltage out, the preamp amplifies the hydrophone voltage, the sonic 16 amplifier shapes and pre-whitens the...frequency will create distorted signals, or a non-linear output. The FM bandwidth approximations are determined by: • 2 x peak deviation + 2 x highest

  1. Bioacoustic field research: a primer to acoustic analyses and playback experiments with primates.

    PubMed

    Fischer, Julia; Noser, Rahel; Hammerschmidt, Kurt

    2013-07-01

    Acoustic analyses of primate vocalizations as well as playback experiments are staple methods in primatology. Acoustic analyses have been used to investigate the influence of factors such as individuality, context, sex, age, and size on variation in calls. More recent studies have expanded our knowledge on the effects of phylogenetic relatedness and the structure of primate vocal repertoires in general. Complementary playback experiments allow direct testing of hypotheses regarding the attribution of meaning to calls, the cognitive mechanisms underpinning responses, and/or the adaptive value of primate behavior. After briefly touching on the historical background of this field of research, we first provide an introduction to recording primate vocalizations and discuss different approaches to describe primate calls in terms of their temporal and spectral properties. Second, we present a tutorial regarding the preparation, execution, and interpretation of field playback experiments, including a review of studies that have used such approaches to investigate the responses to acoustic variation in calls including the integration of contextual and acoustic information, recognition of kin and social relationships, and social knowledge. Based on the review of the literature and our own experience, we make a number of recommendations regarding the most common problems and pitfalls. The power of acoustic analyses typically hinges on the quality of the recordings and the number of individuals represented in the sample. Playback experiments require profound knowledge of the natural behavior of the animals for solid interpretation; experiments should be conducted sparingly, to avoid habituation of the subjects to the occurrence of the calls; experimenter-blind designs chosen whenever possible; and researchers should brace themselves for long periods of waiting times until the appropriate moments to do the experiment arise. If all these aspects are considered, acoustic analyses

  2. Bioacoustic Field Research: A Primer to Acoustic Analyses and Playback Experiments With Primates

    PubMed Central

    FISCHER, JULIA; NOSER, RAHEL; HAMMERSCHMIDT, KURT

    2013-01-01

    Acoustic analyses of primate vocalizations as well as playback experiments are staple methods in primatology. Acoustic analyses have been used to investigate the influence of factors such as individuality, context, sex, age, and size on variation in calls. More recent studies have expanded our knowledge on the effects of phylogenetic relatedness and the structure of primate vocal repertoires in general. Complementary playback experiments allow direct testing of hypotheses regarding the attribution of meaning to calls, the cognitive mechanisms underpinning responses, and/or the adaptive value of primate behavior. After briefly touching on the historical background of this field of research, we first provide an introduction to recording primate vocalizations and discuss different approaches to describe primate calls in terms of their temporal and spectral properties. Second, we present a tutorial regarding the preparation, execution, and interpretation of field playback experiments, including a review of studies that have used such approaches to investigate the responses to acoustic variation in calls including the integration of contextual and acoustic information, recognition of kin and social relationships, and social knowledge. Based on the review of the literature and our own experience, we make a number of recommendations regarding the most common problems and pitfalls. The power of acoustic analyses typically hinges on the quality of the recordings and the number of individuals represented in the sample. Playback experiments require profound knowledge of the natural behavior of the animals for solid interpretation; experiments should be conducted sparingly, to avoid habituation of the subjects to the occurrence of the calls; experimenter-blind designs chosen whenever possible; and researchers should brace themselves for long periods of waiting times until the appropriate moments to do the experiment arise. If all these aspects are considered, acoustic analyses

  3. Modeling of modification experiments involving neutral-gas release

    SciTech Connect

    Bernhardt, P.A.

    1983-01-01

    Many experiments involve the injection of neutral gases into the upper atmosphere. Examples are critical velocity experiments, MHD wave generation, ionospheric hole production, plasma striation formation, and ion tracing. Many of these experiments are discussed in other sessions of the Active Experiments Conference. This paper limits its discussion to: (1) the modeling of the neutral gas dynamics after injection, (2) subsequent formation of ionosphere holes, and (3) use of such holes as experimental tools.

  4. Acoustic Modal Patterns and Striations (AMPS) experiment G-325, Norfolk Public Schools

    NASA Technical Reports Server (NTRS)

    Young, Joy W.

    1995-01-01

    This paper will describe how high school students with the guidance of volunteer mentors were able to successfully complete an acoustics space experiment. Some of the NORSTAR program strategies used to effectively accomplish this goal will be discussed. The experiment and present status of results will be explained.

  5. The Development of Acoustic Experiments for Off-Campus Teaching and Learning

    ERIC Educational Resources Information Center

    Wild, Graham; Swan, Geoff

    2011-01-01

    In this article, we show the implementation of a computer-based digital storage oscilloscope (DSO) and function generator (FG) using the computer's soundcard for off-campus acoustic experiments. The microphone input is used for the DSO, and a speaker jack is used as the FG. In an effort to reduce the cost of implementing the experiment, we examine…

  6. Reproducibility experiments on measuring acoustical properties of rigid-frame porous media (round-robin tests).

    PubMed

    Horoshenkov, Kirill V; Khan, Amir; Bécot, François-Xavier; Jaouen, Luc; Sgard, Franck; Renault, Amélie; Amirouche, Nesrine; Pompoli, Francesco; Prodi, Nicola; Bonfiglio, Paolo; Pispola, Giulio; Asdrubali, Francesco; Hübelt, Jörn; Atalla, Noureddine; Amédin, Celse K; Lauriks, Walter; Boeckx, Laurens

    2007-07-01

    This paper reports the results of reproducibility experiments on the interlaboratory characterization of the acoustical properties of three types of consolidated porous media: granulated porous rubber, reticulated foam, and fiberglass. The measurements are conducted in several independent laboratories in Europe and North America. The studied acoustical characteristics are the surface complex acoustic impedance at normal incidence and plane wave absorption coefficient which are determined using the standard impedance tube method. The paper provides detailed procedures related to sample preparation and installation and it discusses the dispersion in the acoustical material property observed between individual material samples and laboratories. The importance of the boundary conditions, homogeneity of the porous material structure, and stability of the adopted signal processing method are highlighted.

  7. Cruise Report: Long-Range Ocean Acoustic Propagation EXperiment (LOAPEX)

    DTIC Science & Technology

    2005-04-01

    starboard side was used. Both ends of the slip line shown ran through the crane hook to keep them vertical; a strip of masking tape was put around the...2150-3550 m nominal) with a 20-element, 700-in long array (3570- 4270 m nominal) to span the lower caustics in the acoustic arrival pattern with a...during the cruise. The critical equipment belonging to the ship included the stem A-frame, starboard A-frame, both of the ship’s cranes , CTD/rosette

  8. Exhaust System Experiments at NASA's AeroAcoustic Propulsion Lab

    NASA Technical Reports Server (NTRS)

    Bridges, James

    2011-01-01

    This presentation gives an overview of the planned testing in the AeroAcoustic Propulsion Lab (AAPL) in the coming 15 months. It was stressed in the presentation that these are plans that are subject to change due to changes in funding and/or programmatic direction. The first chart shows a simplified schedule of test entries with funding sponsor and dates for each. In subsequent charts are pages devoted to the Objectives and Issues with each test entry, along with a graphic intended to represent the test activity. The chart for each test entry also indicates sponsorship of the activity, and a contact person.!

  9. Acoustic monopoles, dipoles, and quadrupoles: An experiment revisited

    NASA Astrophysics Data System (ADS)

    Russell, Daniel A.; Titlow, Joseph P.; Bemmen, Ya-Juan

    1999-08-01

    A simple and inexpensive demonstration of acoustic monopole, dipole, and quadrupole sources utilizes four 4-in. boxed loudspeakers and a homemade switch box. The switch box allows the speakers to be driven in any combination of phase relationships. Placing the speakers on a rotating stool allows students to measure directivity patterns for monopole, dipole, and quadrupole speaker combinations. Stacking the speakers in a square, all facing the same direction, allows students to aurally compare the frequency and amplitude dependence of sound radiation from monopoles, dipoles, and quadrupoles.

  10. 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.

  11. A numerical method for time dependent acoustic scattering problems involving smart obstacles and incoming waves of small wavelengths

    NASA Astrophysics Data System (ADS)

    Fatone, Lorella; Recchioni, Maria Cristina; Zirilli, Francesco

    2006-05-01

    In this paper we propose a highly parallelizable numerical method for time dependent acoustic scattering problems involving realistic smart obstacles hit by incoming waves having wavelengths small compared with the characteristic dimension of the obstacles. A smart obstacle is an obstacle that when hit by an incoming wave tries to pursue a goal circulating on its boundary a pressure current. In particular we consider obstacles whose goal is to be undetectable and we refer to them as furtive obstacles. These scattering problems are modelled as optimal control problems for the wave equation. We validate the method proposed to solve the optimal control problem considered on some test problems where a "smart" simplified version of the NASA space shuttle is hit by incoming waves with small wavelengths compared to its characteristic dimension. That is we consider test problems with ratio between the characteristic dimension of the obstacle and wavelength of the time harmonic component of the incoming wave up to approximately one hundred. The website: http://www.econ.univpm.it/recchioni/w14 contains animations and virtual reality applications showing some numerical experiments relative to the problems studied in this paper.

  12. Acoustic Propagation Studies For Sperm Whale Phonation Analysis During LADC Experiments

    NASA Astrophysics Data System (ADS)

    Sidorovskaia, Natalia A.; Ioup, George E.; Ioup, Juliette W.; Caruthers, Jerald W.

    2004-11-01

    The Littoral Acoustic Demonstration Center (LADC) conducted a series of passive acoustic experiments in the Northern Gulf of Mexico and the Ligurian Sea in 2001 and 2002. Environmental and acoustic moorings were deployed in areas of large concentrations of marine mammals (mainly, sperm whales). Recordings and analysis of whale phonations are among the objectives of the project. Each mooring had a single autonomously recording hydrophone (Environmental Acoustic Recording System (EARS)) obtained from the U.S. Naval Oceanographic Office after modification to record signals up to 5,859 Hz in the Gulf of Mexico and up to 12,500 Hz in the Ligurian Sea. Self-recording environmental sensors, attached to the moorings, and concurrent environmental ship surveys provided the environmental data for the experiments. The results of acoustic simulations of long-range propagation of the broad-band (500-6,000 Hz) phonation pulses from a hypothetical whale location to the recording hydrophone in the experimental environments are presented. The utilization of the simulation results for an interpretation of the spectral features observed in whale clicks and for the development of tracking algorithms from single hydrophone recordings based on the identification of direct and surface and bottom reflected arrivals are discussed. [Research supported by ONR.

  13. Ground-based acoustic parametric generator impact on the atmosphere and ionosphere in an active experiment

    NASA Astrophysics Data System (ADS)

    Rapoport, Yuriy G.; Cheremnykh, Oleg K.; Koshovy, Volodymyr V.; Melnik, Mykola O.; Ivantyshyn, Oleh L.; Nogach, Roman T.; Selivanov, Yuriy A.; Grimalsky, Vladimir V.; Mezentsev, Valentyn P.; Karataeva, Larysa M.; Ivchenko, Vasyl. M.; Milinevsky, Gennadi P.; Fedun, Viktor N.; Tkachenko, Eugen N.

    2017-01-01

    We develop theoretical basics of active experiments with two beams of acoustic waves, radiated by a ground-based sound generator. These beams are transformed into atmospheric acoustic gravity waves (AGWs), which have parameters that enable them to penetrate to the altitudes of the ionospheric E and F regions where they influence the electron concentration of the ionosphere. Acoustic waves are generated by the ground-based parametric sound generator (PSG) at the two close frequencies. The main idea of the experiment is to design the output parameters of the PSG to build a cascade scheme of nonlinear wave frequency downshift transformations to provide the necessary conditions for their vertical propagation and to enable penetration to ionospheric altitudes. The PSG generates sound waves (SWs) with frequencies f1 = 600 and f2 = 625 Hz and large amplitudes (100-420 m s-1). Each of these waves is modulated with the frequency of 0.016 Hz. The novelty of the proposed analytical-numerical model is due to simultaneous accounting for nonlinearity, diffraction, losses, and dispersion and inclusion of the two-stage transformation (1) of the initial acoustic waves to the acoustic wave with the difference frequency Δf = f2 - f1 in the altitude ranges 0-0.1 km, in the strongly nonlinear regime, and (2) of the acoustic wave with the difference frequency to atmospheric acoustic gravity waves with the modulational frequency in the altitude ranges 0.1-20 km, which then reach the altitudes of the ionospheric E and F regions, in a practically linear regime. AGWs, nonlinearly transformed from the sound waves, launched by the two-frequency ground-based sound generator can increase the transparency of the ionosphere for the electromagnetic waves in HF (MHz) and VLF (kHz) ranges. The developed theoretical model can be used for interpreting an active experiment that includes the PSG impact on the atmosphere-ionosphere system, measurements of electromagnetic and acoustic fields, study of

  14. Wavelet Preprocessing of Acoustic Signals

    DTIC Science & Technology

    1991-12-01

    wavelet transform to preprocess acoustic broadband signals in a system that discriminates between different classes of acoustic bursts. This is motivated by the similarity between the proportional bandwidth filters provided by the wavelet transform and those found in biological hearing systems. The experiment involves comparing statistical pattern classifier effects of wavelet and FFT preprocessed acoustic signals. The data used was from the DARPA Phase I database, which consists of artificially generated signals with real ocean background. The

  15. Patterns in Group Involvement Experiences during College: Identifying a Taxonomy

    ERIC Educational Resources Information Center

    Dugan, John P.

    2013-01-01

    This study explored whether latent phenomena could be identified to classify students based on their patterns of involvement in cocurricular group experiences. The sample was comprised of 11,209 seniors from 50 institutions. A total of 4 latent factors were identified and students were classified into one of 8 latent classes. Findings offer new…

  16. School Experiences of an Adolescent with Medical Complexities Involving Incontinence

    ERIC Educational Resources Information Center

    Filce, Hollie Gabler; Bishop, John B.

    2014-01-01

    The educational implications of chronic illnesses which involve incontinence are not well represented in the literature. The experiences of an adolescent with multiple complex illnesses, including incontinence, were explored via an intrinsic case study. Data were gathered from the adolescent, her mother, and teachers through interviews, email…

  17. A hierarchical generalization of the acoustic reciprocity theorem involving higher-order derivatives and interaction quantities.

    PubMed

    Lin, Ju; Li, Jie; Li, Xiaolei; Wang, Ning

    2016-10-01

    An acoustic reciprocity theorem is generalized, for a smoothly varying perturbed medium, to a hierarchy of reciprocity theorems including higher-order derivatives of acoustic fields. The standard reciprocity theorem is the first member of the hierarchy. It is shown that the conservation of higher-order interaction quantities is related closely to higher-order derivative distributions of perturbed media. Then integral reciprocity theorems are obtained by applying Gauss's divergence theorem, which give explicit integral representations connecting higher-order interactions and higher-order derivative distributions of perturbed media. Some possible applications to an inverse problem are also discussed.

  18. Experiments in Molecular Physics with an Acoustic Interferometer

    ERIC Educational Resources Information Center

    Rossing, Thomas D.

    1973-01-01

    A device which provides an inexpensive means for making precise studies of the kinetics of gas molecules is discussed. Two experiments are described: (1) Measurement of the vibrational relaxation time of gas molecules and (2) determination of intermolecular forces in molecules. (Author/DF)

  19. Forensic acoustics: An overview of the process

    NASA Astrophysics Data System (ADS)

    Weissenburger, J. T.

    2003-10-01

    There is a potential role for the acoustical expert in litigation. The technical issues may involve aeroacoustics, underwater acoustics, physical effects of sound, environmental acoustics, noise, architectural acoustics, physiological acoustics, speech and hearing, music, psychoacoustics and/or bioacoustics. This brief paper offers an overview of the process of being an expert, the qualifications to be an expert and what is expected of an expert. The six general phases of an expert's involvement-retention, investigation, discovery, deposition, preparation, trial-are addressed. Some antidotal experiences are presented.

  20. GLider Acoustics Sensing of Sediments (GLASS): Experiments and Data Analysis

    DTIC Science & Technology

    2013-12-01

    to 8◦. Numerical mod- eling of the impact of vertical array tilt on seabed characterization was performed using OASES [11]. The input parameters to...been deployed in two different shallow-water environments during the GLASS’12 (soft bottom) and GLASS’13 (hard bottom) experiments. The OASES noise...from ambient noise is modeled by OASES [11], and the fitness of the modeling result to the experimen- tal data is measured by a least-mean-square error

  1. LOAPEX: The Long-Range Ocean Acoustic Propagation EXperiment

    DTIC Science & Technology

    2009-01-01

    C. Eriksen, T. J. Osse, R. D. Light, T. Wen, T. W. Lehman, P. L. Sabin, J. W. Ballard, and A. M . Chiodi , “Seaglider: A long range autonomous...Propagation EXperiment James A. Mercer, John A. Colosi, Bruce M . Howe, Matthew A. Dzieciuch, Ralph Stephen, and Peter F. Worcester Abstract—This paper...from various depths to a pair of vertical hydrophone arrays covering 3500 m of the water column, and to several bottom-mounted horizontal line arrays

  2. Guidelines for reporting experiments involving animals: the ARRIVE guidelines.

    PubMed

    McGrath, J C; Drummond, G B; McLachlan, E M; Kilkenny, C; Wainwright, C L

    2010-08-01

    British Journal of Pharmacology (BJP) is pleased to publish a new set of guidelines for reporting research involving animals, simultaneously with several other journals; the 'ARRIVE' guidelines (Animals in Research: Reporting In Vivo Experiments). This editorial summarizes the background to the guidelines, gives our view of their significance, considers aspects of specific relevance to pharmacology, re-states BJP's guidelines for authors on animal experiments and indicates our commitment to carrying on discussion of this important topic. We also invite feedback via the British Pharmacological Society website.

  3. Numerical investigation of the seismo-acoustic responses of the Source Physics Experiment underground explosions

    NASA Astrophysics Data System (ADS)

    Antoun, T.; Ezzedine, S. M.; Vorobiev, O.; Glenn, L. A.

    2015-12-01

    We have performed three-dimensional high resolution simulations of underground explosions conducted recently in jointed rock outcrop as part of the Source Physics Experiment (SPE) being conducted at the Nevada National Security Site (NNSS). The main goal of the current study is to investigate the effects of the structural and geomechanical properties on the spall phenomena due to underground explosions and its subsequent effect on the seismo-acoustic signature at far distances. Two parametric studies have been undertaken to assess the impact of different 1) conceptual geological models including a single layer and two layers model, with and without joints and with and without varying geomechanical properties, and 2) depth of bursts of the explosions and explosion yields. Through these investigations we have explored not only the near-field response of the explosions but also the far-field responses of the seismic and the acoustic signatures. The near-field simulations were conducted using the Eulerian and Lagrangian codes, GEODYN and GEODYN -L, respectively, while the far-field seismic simulations were conducted using the elastic wave propagation code, WPP, and the acoustic response using the Kirchhoff-Helmholtz-Rayleigh time-dependent approximation code, KHR. Though a series of simulations, we have recorded the velocity field histories a) at the ground surface on an acoustic-source-patch for the acoustic simulations, and 2) on a seismic-source-box for the seismic simulations. We first analyzed the SPE3 and SPE4-prime experimental data and simulated results, and then simulated SPE5, SPE6/7 to anticipate their seismo-acoustic responses given conditions of uncertainties. SPE experiments were conducted in a granitic formation; we have extended the parametric study to include other geological settings such dolomite and alluvial formations. These parametric studies enabled us 1) investigating the geotechnical and geophysical key parameters that impact the seismo-acoustic

  4. Alcohol Involvement in First Sexual Intercourse Experiences of Adolescent Girls

    PubMed Central

    Livingston, Jennifer A.; Testa, Maria; Windle, Michael; Bay-Cheng, Laina Y.

    2015-01-01

    This study examines whether use of alcohol at first coitus is associated with increased sexual risk for young women. First coitus is the focus of the investigation because it is a memorable, formative experience that has implications for subsequent sexual health. A community sample of young women ages 18 – 19 years (N = 227) completed retrospective interviews. Characteristics and perceptions of the first coital event were examined using chi squares and one-way multivariate analysis of variance (MANOVA) to determine if there were differences based on alcohol-involvement. Alcohol-involved first coitus events occurred in social settings with risky partners, were rated less positively, and were non-consensual relative to those that did not involve alcohol. Alcohol use was not related to condom use. Alcohol-involvement was associated with subsequent pairing of alcohol with sex and incapacitated rape. Adolescent alcohol use occurs in contexts that increases young women’s sexual risk through exposure to risky partners. PMID:26121927

  5. [Intervention for psychotic experience involved in offending behavior].

    PubMed

    Kikuchi, Akiko

    2010-01-01

    Cognitive behaviour therapy for psychosis (CBTp) as an adjunct to standard psychiatric care can make substantial difference in symptom distress, insight, and adherence to treatment. However, studies on the effect of cognitive behaviour therapy on offending behaviours influenced by psychotic experience are in its very early stage. This paper summarizes the conceptualization, treatment programme development, and individual therapy to address psychotic experience involved in offending behaviours in mentally disordered offenders (MDOs). It is argued that, 1) intensive intervention is recommended for those MDOs with general risk factors in addition to psychosis-related-risk factors, 2) MDOs may benefit from CBTp and general offending behaviour programmes, 3) it is important to focus on aggression-neutralization cognitions.

  6. The effect of boundaries on the ion acoustic beam-plasma instability in experiment and simulation

    SciTech Connect

    Rapson, Christopher; Grulke, Olaf; Matyash, Konstantin; Klinger, Thomas

    2014-05-15

    The ion acoustic beam-plasma instability is known to excite strong solitary waves near the Earth's bow shock. Using a double plasma experiment, tightly coupled with a 1-dimensional particle-in-cell simulation, the results presented here show that this instability is critically sensitive to the experimental conditions. Boundary effects, which do not have any counterpart in space or in most simulations, unavoidably excite parasitic instabilities. Potential fluctuations from these instabilities lead to an increase of the beam temperature which reduces the growth rate such that non-linear effects leading to solitary waves are less likely to be observed. Furthermore, the increased temperature modifies the range of beam velocities for which an ion acoustic beam plasma instability is observed.

  7. Biological Significance of Acoustic Impacts on Marine Mammals: Examples Using an Acoustic Recording tag to Define Acoustic Exposure of Sperm Whales, Physeter catodon, Exposed to Airgun Sounds in Controlled Exposure Experiments

    NASA Astrophysics Data System (ADS)

    Tyack, P. L.; Johnson, M. P.; Madsen, P. T.; Miller, P. J.; Lynch, J.

    2006-05-01

    There has been considerable debate about how to regulate behavioral disruption in marine mammals. The U.S. Marine Mammal Protection Act prohibits "taking" marine mammals, including harassment, which is defined as injury or disruption of behavioral patterns. A 2005 report by the National Academy of Sciences focuses on the need to analyze acoustic impacts on marine mammal behavior in terms of biological significance. The report develops a model for predicting population consequences of acoustic impacts. One of the key data gaps involves methods to estimate the impact of disruption on an animal's ability to complete life functions critical for growth, survival, and reproduction. One of the few areas where theory and data are available involves foraging energetics. Patrick Miller in the next talk and I will discuss an example study designed to evaluate the impact of exposure to seismic survey on the foraging energetics of sperm whales. As petroleum exploration moves offshore to deep water, there is increasing overlap between seismic exploration and deep diving toothed whales such as the sperm whale which is listed by the US as an endangered species. With support from the US Minerals Management Service and the Industry Research Funding Coalition, we tagged sperm whales with tags that can record sound, orientation, acceleration, temperature and depth. Eight whales tagged in the Gulf of Mexico during 2002-2003 were subjects in 5 controlled experiments involving exposure to sounds of an airgun array. One critical component of evaluating effects involves quantifying exposure at the animal. While the on-axis signature of airgun arrays has been well quantified, there are few broadband calibrated measurements in the water column displaced horizontally away from the downward-directed beam. The acoustic recording tags provide direct data on sounds as received at the animals. Due to multipath propagation, multiple sound pulses were recorded on the tagged whales for each firing of

  8. Surgical removal of giant acoustic neurinomas involving the skull base. Report of two cases.

    PubMed

    Sawamura, Y; Nakagawa, Y; Ikota, T; Abe, H

    1989-10-01

    Neurinomas arising from the peripheral branch of the acoustic nerve distal to the internal auditory canal in the temporal bone are rare. Two advanced skull-base neurinomas are described which were situated mainly in the temporal petrous bone, and extended to the parapharyngeal space anteriorly, to the lateral cervical portion inferiorly, into the sphenoidal sinus medially, and into the middle and posterior cranial fossae compressing the brain stem. Both patients had been deaf for several years without other neurological deficits. The operative findings revealed that the fifth, seventh, and caudal cranial nerves were intact; therefore, it was suspected that these neurinomas originated primarily within the cochlea or the vestibule in the temporal bone. The tumors were completely removed via an extradural approach, with good results. Since the surgical treatment of such advanced skull-base neurinomas is difficult, the operative infratemporal fossa approach is described in detail.

  9. Student involvement in the UK sex industry: motivations and experiences.

    PubMed

    Sagar, Tracey; Jones, Debbie; Symons, Katrien; Tyrie, Jacky; Roberts, Ron

    2016-12-01

    The Student Sex Work Project was set up in 2012 in the United Kingdom (UK) to locate students who are involved in the sex industry, to discover their motivations and needs, and in doing so provide an evidence base to consider the development of policy and practice within Higher Education. As part of this initiative, a large survey was undertaken comprising students from throughout the UK. Reporting on the findings from this survey, the article sheds some light on what occupations students take up in the sex industry, what motivates their participation and how they experience the work. The study also offers a much-needed empirical input to the ongoing academic debates on the nature of sex work. The results suggest that there can be little doubt of a student presence within the sex industry in the UK. The motivations and experiences of student sex workers cover elements of agency and choice as well as of force and exploitation and it is suggested that student sex work is best understood from a polymorphous framework which leaves room for a wide variety of experiences and challenges.

  10. Early acoustic discrimination experience ameliorates auditory processing deficits in male rats with cortical developmental disruption

    PubMed Central

    Threlkeld, Steven W.; Hill, Courtney A.; Rosen, Glenn D.; Fitch, R. Holly

    2014-01-01

    Auditory temporal processing deficits have been suggested to play a causal role in language learning impairments, and evidence of cortical developmental anomalies (microgyria (MG), ectopia) has been reported for language-impaired populations. Rodent models have linked these features, by showing deficits in auditory temporal discrimination for rats with neuronal migration anomalies (MG, ectopia). Since evidence from human studies suggests that training with both speech and non-speech acoustic stimuli may improve language performance in developmentally language-disabled populations, we were interested in whether/how maturation and early experience might influence auditory processing deficits seen in male rats with induced focal cortical MG. Results showed that for both simple (Normal single tone), as well as increasingly complex auditory discrimination tasks (Silent gap in white noise and FM sweep), prior experience significantly improved acoustic discrimination performance -- in fact, beyond improvements seen with maturation only. Further, we replicated evidence that young adult rats with MG were significantly impaired at discriminating FM sweeps compared to shams. However, these MG effects were no longer seen when experienced subjects were retested in adulthood (even though deficits in short duration FM sweep detection were seen for adult MG rats with no early experience). Thus while some improvements in auditory processing were seen with normal maturation, the effects of early experience were even more profound, in fact resulting in amelioration of MG effects seen at earlier ages. These findings support the clinical view that early training intervention with appropriate acoustic stimuli could similarly ameliorate long-term processing impairments seen in some language-impaired children. PMID:19460626

  11. The development of acoustic experiments for off-campus teaching and learning

    NASA Astrophysics Data System (ADS)

    Wild, Graham; Swan, Geoff

    2011-05-01

    In this article, we show the implementation of a computer-based digital storage oscilloscope (DSO) and function generator (FG) using the computer's soundcard for off-campus acoustic experiments. The microphone input is used for the DSO, and a speaker jack is used as the FG. In an effort to reduce the cost of implementing the experiment, we examine software available for free, online. A small number of applications were compared in terms of their interface and functionality, for both the DSO and the FG. The software was then used to investigate standing waves in pipes using the computer-based DSO. Standing wave theory taught in high school and in first year physics is based on a one-dimensional model. With the use of the DSO's fast Fourier transform function, the experimental uncertainly alone was not sufficient to account for the difference observed between the measure and the calculated frequencies. Hence the original experiment was expanded upon to include the end correction effect. The DSO was also used for other simple acoustics experiments, in areas such as the physics of music.

  12. An undergraduate experiment demonstrating the physics of metamaterials with acoustic waves and soda cans

    NASA Astrophysics Data System (ADS)

    Wilkinson, James T.; Whitehouse, Christopher B.; Oulton, Rupert F.; Gennaro, Sylvain D.

    2016-01-01

    We describe a novel undergraduate research project that highlights the physics of metamaterials with acoustic waves and soda cans. We confirm the Helmholtz resonance nature of a single can by measuring its amplitude and phase response to a sound wave. Arranging multiple cans in arrays smaller than the wavelength, we then design an antenna that redirects sound into a preferred direction. The antenna can be thought of as a new resonator, composed of artificially engineered meta-atoms, similar to a metamaterial. These experiments are illustrative, tactile, and open ended so as to enable students to explore the physics of matter/wave interaction.

  13. Acoustic Experiment to Measure the Bulk Viscosity of Near-Critical Xenon in Microgravity

    NASA Technical Reports Server (NTRS)

    Gillis, K. A.; Shinder, I.; Moldover, M. R.; Zimmerli, G. A.

    2002-01-01

    We plan a rigorous test of the theory of dynamic scaling by accurately measuring the bulk viscosity of xenon in microgravity 50 times closer to the critical temperature T(sub c) than previous experiments. The bulk viscosity zeta (or "second viscosity" or "dilational viscosity") will be determined by measuring the attenuation length of sound alpha lambda and also measuring the frequency-dependence of the speed of sound. For these measurements, we developed a unique Helmholtz resonator and specialized electro-acoustic transducers. We describe the resonator, the transducers, their performance on Earth, and their expected performance in microgravity.

  14. 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

  15. Comprehensive comparisons of geodesic acoustic mode characteristics and dynamics between Tore Supra experiments and gyrokinetic simulations

    SciTech Connect

    Storelli, A. Vermare, L.; Hennequin, P.; Gürcan, Ö. D.; Singh, Rameswar; Morel, P.; Dif-Pradalier, G.; Sarazin, Y.; Garbet, X.; Grandgirard, V.; Ghendrih, P.; Görler, T.

    2015-06-15

    In a dedicated collisionality scan in Tore Supra, the geodesic acoustic mode (GAM) is detected and identified with the Doppler backscattering technique. Observations are compared to the results of a simulation with the gyrokinetic code GYSELA. We found that the GAM frequency in experiments is lower than predicted by simulation and theory. Moreover, the disagreement is higher in the low collisionality scenario. Bursts of non harmonic GAM oscillations have been characterized with filtering techniques, such as the Hilbert-Huang transform. When comparing this dynamical behaviour between experiments and simulation, the probability density function of GAM amplitude and the burst autocorrelation time are found to be remarkably similar. In the simulation, where the radial profile of GAM frequency is continuous, we observed a phenomenon of radial phase mixing of the GAM oscillations, which could influence the burst autocorrelation time.

  16. Features of CO2 fracturing deduced from acoustic emission and microscopy in laboratory experiments

    NASA Astrophysics Data System (ADS)

    Ishida, Tsuyoshi; Chen, Youqing; Bennour, Ziad; Yamashita, Hiroto; Inui, Shuhei; Nagaya, Yuya; Naoi, Makoto; Chen, Qu; Nakayama, Yoshiki; Nagano, Yu

    2016-11-01

    We conducted hydraulic fracturing (HF) experiments on 170 mm cubic granite specimens with a 20 mm diameter central hole to investigate how fluid viscosity affects HF process and crack properties. In experiments using supercritical carbon dioxide (SC-CO2), liquid carbon dioxide (L-CO2), water, and viscous oil with viscosity of 0.051-336.6 mPa · s, we compared the results for breakdown pressure, the distribution and fracturing mechanism of acoustic emission, and the microstructure of induced cracks revealed by using an acrylic resin containing a fluorescent compound. Fracturing with low-viscosity fluid induced three-dimensionally sinuous cracks with many secondary branches, which seem to be desirable pathways for enhanced geothermal system, shale gas recovery, and other processes.

  17. Acoustic-hydrophysical experiments in the coastal zone of the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Akulichev, V. A.; Golov, A. A.; Morgunov, Yu. N.; Strobykin, D. S.; Kim, Kiseon; Kim, Chansan

    2012-06-01

    This paper presents the results of a pilot experiment on determination of the possibility for effective application of the navigational systems of autonomous robots and remote tools of water structure and dynamics monitoring in shallow water areas. The experiment was based on investigation of the regularities of formation and interaction between hydroacoustic and hydrophysical fields when sounded by complex phase-shift keyed signals with the central frequency of 2500 Hz. The possibility of monitoring of temperature and current fields by acoustic tomography methods in the water area of several square kilometers in size and no more than 10 m in depth, at depth changes up to several meters due to tidal effects, was studied. Additionally, the possibility and precision of solution of navigational problems for underwater objects at such shallow depths was studied. For this purpose a hardware-software complex, equipped with two sources of navigational signals and an imitator of the submersible receiver path, was used.

  18. Results From a Parametric Acoustic Liner Experiment Using P and W GEN1 HSR Mixer/Ejector Model

    NASA Technical Reports Server (NTRS)

    Boyd, Kathleen C.; Wolter, John D.

    2004-01-01

    This report documents the results of an acoustic liner test performed using a Gen 1 HSR mixer/ejector model installed on the Jet Exit Rig in the Nozzle Acoustic Test Rig in the Aeroacoustic Propulsion Laboratory or NASA Glenn Research Center. Acoustic liner effectiveness and single-component thrust performance results are discussed. Results from 26 different types of single-degree-of-freedom and bulk material liners are compared with each other and against a hardwall baseline. Design parameters involving all aspects of the facesheet, the backing cavity, and the type of bulk material were varied in order to study the effects of these design features on the acoustic impedance, acoustic effectiveness and on nozzle thrust performance. Overall, the bulk absorber liners are more effective at reducing the jet noise than the single-degree-of-freedom liners. Many of the design parameters had little effect on acoustic effectiveness, such as facesheeet hole diameter and honeycomb cell size. A relatively large variation in the impedance of the bulk absorber in a bulk liner is required to have a significant impact on the noise reduction. The thrust results exhibit a number of consistent trends, supporting the validity of this new addition to the facility. In general, the thrust results indicate that thrust performance benefits from increased facesheet thickness and decreased facesheet porosity.

  19. Dictums for problem solving and approximation in mathematical acoustics: examples involving low-frequency vibration and radiation.

    PubMed

    Pierce, Allan D; Thiam, Amadou G

    2012-03-01

    A sequence of dictums for mathematical acoustics is given representing opinions intended to be regarded as authoritative, but not necessarily universally agreed upon. The dictums are presented in the context of the detailed solution for a class of problems involving the forced vibration of a long cylinder protruding half-way into a half-space bounded by a compliant surface (impedance boundary) characterized by a spring constant. One limiting case corresponds to a cylinder vibrating within an infinite rigid baffle, and another limiting case corresponds to a vibrating cylinder on the compliant surface of an incompressible fluid. The second limiting case is identified as analogous to that of a floating half-submerged cylinder whose vibrations cause water waves to propagate over the surface. Attention is focused on vibrations at very low frequencies. Difficulties with insuring a causal solution are pointed out and dictums are given as to how one overcomes such difficulties. Various approximation techniques are described. The derivations involve application of the theory of complex variables and the method of matched asymptotic expansions, and the results include the apparent entrained mass in the near field of the cylinder and the radiation resistance per unit length experienced by the vibrating cylinder.

  20. Role of transient water pressure in quarrying: A subglacial experiment using acoustic emissions

    NASA Astrophysics Data System (ADS)

    Cohen, D.; Hooyer, T. S.; Iverson, N. R.; Thomason, J. F.; Jackson, M.

    2006-09-01

    Probably the most important mechanism of glacial erosion is quarrying: the growth and coalescence of cracks in subglacial bedrock and dislodgement of resultant rock fragments. Although evidence indicates that erosion rates depend on sliding speed, rates of crack growth in bedrock may be enhanced by changing stresses on the bed caused by fluctuating basal water pressure in zones of ice-bed separation. To study quarrying in real time, a granite step, 12 cm high with a crack in its stoss surface, was installed at the bed of Engabreen, Norway. Acoustic emission sensors monitored crack growth events in the step as ice slid over it. Vertical stresses, water pressure, and cavity height in the lee of the step were also measured. Water was pumped to the lee of the step several times over 8 days. Pumping initially caused opening of a leeward cavity, which then closed after pumping was stopped and water pressure decreased. During cavity closure, acoustic emissions emanating mostly from the vicinity of the base of the crack in the step increased dramatically. With repeated pump tests this crack grew with time until the step's lee surface was quarried. Our experiments indicate that fluctuating water pressure caused stress thresholds required for crack growth to be exceeded. Natural basal water pressure fluctuations should also concentrate stresses on rock steps, increasing rates of crack growth. Stress changes on the bed due to water pressure fluctuations will increase in magnitude and duration with cavity size, which may help explain the effect of sliding speed on erosion rates.

  1. Axial vibrations of brass wind instrument bells and their acoustical influence: Experiments.

    PubMed

    Moore, Thomas R; Gorman, Britta R; Rokni, Michelle; Kausel, Wilfried; Chatziioannou, Vasileios

    2015-08-01

    It has recently been proposed that the effects of structural vibrations on the radiated sound of brass wind instruments may be attributable to axial modes of vibration with mode shapes that contain no radial nodes [Kausel, Chatziioannou, Moore, Gorman, and Rokni, J. Acoust. Soc. Am. 137, 3149-3162 (2015)]. Results of experiments are reported that support this theory. Mechanical measurements of a trumpet bell demonstrate that these axial modes do exist in brass wind instruments. The quality factor of the mechanical resonances can be on the order of 10 or less, making them broad enough to encompass the frequency range of previously reported effects attributed to bell vibrations. Measurements of the input impedance show that damping bell vibrations can result in impedance changes of up to 5%, in agreement with theory. Measurements of the acoustic transfer function demonstrate that the axial vibrations couple to the internal sound field as proposed, resulting in changes in the transfer function of approximately 1 dB. In agreement with theory, a change in the sign of the effect is observed at the frequency of the structural resonance.

  2. Investigation of the Acoustic Source Characteristics of High Energy Laser Pulses: Models and Experiment

    DTIC Science & Technology

    2008-06-01

    consistent with the expected approximately 1/r relationship for pressure amplitudes under 100MPa. The modeling effort employed AUTODYN , a finite...agreed with Vogel’s measured values. The efficiency, pulse length, pulse shape, and variation of pressure amplitude with range achieved with AUTODYN ...Nonlinear Acoustics, AUTODYN , Acoustic Modeling, Shock Acoustics 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY

  3. Ultrasonic power transfer from a spherical acoustic wave source to a free-free piezoelectric receiver: Modeling and experiment

    NASA Astrophysics Data System (ADS)

    Shahab, S.; Gray, M.; Erturk, A.

    2015-03-01

    Contactless powering of small electronic components has lately received growing attention for wireless applications in which battery replacement or tethered charging is undesired or simply impossible, and ambient energy harvesting is not a viable solution. As an alternative to well-studied methods of contactless energy transfer, such as the inductive coupling method, the use of ultrasonic waves transmitted and received by piezoelectric devices enables larger power transmission distances, which is critical especially for deep-implanted electronic devices. Moreover, energy transfer by means of acoustic waves is well suited in situations where no electromagnetic fields are allowed. The limited literature of ultrasonic acoustic energy transfer is mainly centered on proof-of-concept experiments demonstrating the feasibility of this method, lacking experimentally validated modeling efforts for the resulting multiphysics problem that couples the source and receiver dynamics with domain acoustics. In this work, we present fully coupled analytical, numerical, and experimental multiphysics investigations for ultrasonic acoustic energy transfer from a spherical wave source to a piezoelectric receiver bar that operates in the 33-mode of piezoelectricity. The fluid-loaded piezoelectric receiver under free-free mechanical boundary conditions is shunted to an electrical load for quantifying the electrical power output for a given acoustic source strength of the transmitter. The analytical acoustic-piezoelectric structure interaction modeling framework is validated experimentally, and the effects of system parameters are reported along with optimal electrical loading and frequency conditions of the receiver.

  4. Ultrasonic power transfer from a spherical acoustic wave source to a free-free piezoelectric receiver: Modeling and experiment

    SciTech Connect

    Shahab, S.; Gray, M.; Erturk, A.

    2015-03-14

    Contactless powering of small electronic components has lately received growing attention for wireless applications in which battery replacement or tethered charging is undesired or simply impossible, and ambient energy harvesting is not a viable solution. As an alternative to well-studied methods of contactless energy transfer, such as the inductive coupling method, the use of ultrasonic waves transmitted and received by piezoelectric devices enables larger power transmission distances, which is critical especially for deep-implanted electronic devices. Moreover, energy transfer by means of acoustic waves is well suited in situations where no electromagnetic fields are allowed. The limited literature of ultrasonic acoustic energy transfer is mainly centered on proof-of-concept experiments demonstrating the feasibility of this method, lacking experimentally validated modeling efforts for the resulting multiphysics problem that couples the source and receiver dynamics with domain acoustics. In this work, we present fully coupled analytical, numerical, and experimental multiphysics investigations for ultrasonic acoustic energy transfer from a spherical wave source to a piezoelectric receiver bar that operates in the 33-mode of piezoelectricity. The fluid-loaded piezoelectric receiver under free-free mechanical boundary conditions is shunted to an electrical load for quantifying the electrical power output for a given acoustic source strength of the transmitter. The analytical acoustic-piezoelectric structure interaction modeling framework is validated experimentally, and the effects of system parameters are reported along with optimal electrical loading and frequency conditions of the receiver.

  5. Development of sound localization mechanisms in the mongolian gerbil is shaped by early acoustic experience.

    PubMed

    Seidl, Armin H; Grothe, Benedikt

    2005-08-01

    Sound localization is one of the most important tasks performed by the auditory system. Differences in the arrival time of sound at the two ears are the main cue to localize low-frequency sound in the azimuth. In the mammalian brain, such interaural time differences (ITDs) are encoded in the auditory brain stem; first by the medial superior olive (MSO) and then transferred to higher centers, such as the dorsal nucleus of the lateral lemniscus (DNLL), a brain stem nucleus that gets a direct input from the MSO. Here we demonstrate for the first time that ITD sensitivity in gerbils undergoes a developmental maturation after hearing onset. We further show that this development can be disrupted by altering the animal's acoustic experience during a critical period. In animals that had been exposed to omnidirectional white noise during a restricted time period right after hearing onset, ITD tuning did not develop normally. Instead, it was similar to that of juvenile animals 3 days after hearing onset, with the ITD functions not adjusted to the physiological range. Animals that had been exposed to omnidirectional noise as adults did not show equivalent abnormal ITD tuning. The development presented here is in contrast to that of the development of neuronal representation of ITDs in the midbrain of barn owls and interaural intensity differences in ferrets, where the representations are adjusted by an interaction of auditory and visual inputs. The development of ITD tuning presented here most likely depends on normal acoustic experience and may be related to the maturation of inhibitory inputs to the ITD detector itself.

  6. Aboriginal Street-involved Youth Experience Elevated Risk of Incarceration

    PubMed Central

    Barker, Brittany; Alfred, Gerald Taiaiake; Fleming, Kim; Nguyen, Paul; Wood, Evan; Kerr, Thomas; DeBeck, Kora

    2015-01-01

    Objectives Past research has identified risk factors associated with incarceration among adult Aboriginal populations; however, less is known about incarceration among street-involved Aboriginal youth. Therefore, we undertook this study to longitudinally investigate recent reports of incarceration among a prospective cohort of street-involved youth in Vancouver, Canada. Study Design Prospective cohort study. Methods Data were collected from a cohort of street-involved, drug-using youth from September 2005 to May 2013. Multivariate generalized estimating equation analyses were employed to examine the potential relationship between Aboriginal ancestry and recent incarceration. Results Among our sample of 1050 youth, 248 (24%) reported being of aboriginal ancestry, and 378 (36%) reported being incarcerated in the previous six months at some point during the study period. In multivariate analysis controlling for a range of potential confounders including drug use patterns and other risk factors, Aboriginal ancestry remained significantly associated with recent incarceration (adjusted odds ratio [AOR]=1.44; 95% confidence interval [CI]: 1.12–1.86). Conclusions Even after adjusting for drug use patterns and other risk factors associated with incarceration, this study found that Aboriginal street-involved youth were still significantly more likely to be incarcerated than their non-Aboriginal peers. Given the established harms associated with incarceration these findings underscore the pressing need for systematic reform including culturally appropriate interventions to prevent Aboriginal youth from becoming involved with the criminal justice system. PMID:26390949

  7. Role of transient water pressure in quarrying: A subglacial experiment using acoustic emissions

    USGS Publications Warehouse

    Cohen, D.; Hooyer, T.S.; Iverson, N.R.; Thomason, J.F.; Jackson, M.

    2006-01-01

    Probably the most important mechanism of glacial erosion is quarrying: the growth and coalescence of cracks in subglacial bedrock and dislodgement of resultant rock fragments. Although evidence indicates that erosion rates depend on sliding speed, rates of crack growth in bedrock may be enhanced by changing stresses on the bed caused by fluctuating basal water pressure in zones of ice-bed separation. To study quarrying in real time, a granite step, 12 cm high with a crack in its stoss surface, was installed at the bed of Engabreen, Norway. Acoustic emission sensors monitored crack growth events in the step as ice slid over it. Vertical stresses, water pressure, and cavity height in the lee of the step were also measured. Water was pumped to the lee of the step several times over 8 days. Pumping initially caused opening of a leeward cavity, which then closed after pumping was stopped and water pressure decreased. During cavity closure, acoustic emissions emanating mostly from the vicinity of the base of the crack in the step increased dramatically. With repeated pump tests this crack grew with time until the step's lee surface was quarried. Our experiments indicate that fluctuating water pressure caused stress thresholds required for crack growth to be exceeded. Natural basal water pressure fluctuations should also concentrate stresses on rock steps, increasing rates of crack growth. Stress changes on the bed due to water pressure fluctuations will increase in magnitude and duration with cavity size, which may help explain the effect of sliding speed on erosion rates. Copyright 2006 by the American Geophysical Union.

  8. Producing acoustic 'Frozen Waves': simulated experiments with diffraction/attenuation resistant beams in lossy media.

    PubMed

    Prego-Borges, José L; Zamboni-Rached, Michel; Recami, Erasmo; Costa, Eduardo Tavares

    2014-08-01

    The so-called Localized Waves (LW), and the "Frozen Waves" (FW), have raised significant attention in the areas of Optics and Ultrasound, because of their surprising energy localization properties. The LWs resist the effects of diffraction for large distances, and possess an interesting self-reconstruction -self-healing- property (after obstacles with size smaller than the antenna's); while the FWs, a sub-class of LWs, offer the possibility of arbitrarily modeling the longitudinal field intensity pattern inside a prefixed interval, for instance 0⩽z⩽L, of the wave propagation axis. More specifically, the FWs are localized fields "at rest", that is, with a static envelope (within which only the carrier wave propagates), and can be endowed moreover with a high transverse localization. In this paper we investigate, by simulated experiments, various cases of generation of ultrasonic FW fields, with the frequency of f0=1 MHz in a water-like medium, taking account of the effects of attenuation. We present results of FWs for distances up to L=80 mm, in attenuating media with absorption coefficient α in the range 70⩽α⩽170 dB/m. Such simulated FW fields are constructed by using a procedure developed by us, via appropriate finite superpositions of monochromatic ultrasonic Bessel beams. We pay due attention to the selection of the FW parameters, constrained by the rather tight restrictions imposed by experimental Acoustics, as well as to some practical implications of the transducer design. The energy localization properties of the Frozen Waves can find application even in many medical apparatus, such as bistouries or acoustic tweezers, as well as for treatment of diseased tissues (in particular, for the destruction of tumor cells, without affecting the surrounding tissues; also for kidney stone shuttering, etc.).

  9. Acoustic resonances in microfluidic chips: full-image micro-PIV experiments and numerical simulations.

    PubMed

    Hagsäter, S M; Jensen, T Glasdam; Bruus, H; Kutter, J P

    2007-10-01

    We show that full-image micro-PIV analysis in combination with images of transient particle motion is a powerful tool for experimental studies of acoustic radiation forces and acoustic streaming in microfluidic chambers under piezo-actuation in the MHz range. The measured steady-state motion of both large 5 microm and small 1 microm particles can be understood in terms of the acoustic eigenmodes or standing ultra-sound waves in the given experimental microsystems. This interpretation is supported by numerical solutions of the corresponding acoustic wave equation.

  10. Shipboard acoustic doppler current profiler data collected during the Western Tropical Atlantic Experiment (WESTRAX) 1991. Technical memo

    SciTech Connect

    Routt, J.A.; Wilson, W.D.

    1992-11-01

    The long-term goal of ongoing and future research in the western tropical Atlantic is to estimate the cross-equatorial transport of water and heat. The overall goals of those involved in the Western Tropical Atlantic Experiment (WESTRAX) are (a) to describe the annual cycle in the large-scale structure of the velocity and hydrographic properties over the full water column in the western tropical Atlantic Ocean between the equator and 15 degrees N, and (b) to compare data and models in order to better understand the physics of the regional circulation in the broader context of Atlantic basin thermohaline circulation. The results of this combined effort will greatly improve our understanding of this complex boundary current region and establish the basis for efficient long-term climatic monitoring of the critical meridional fluxes of mass and heat across the tropical Atlantic. This report presents the Acoustic Doppler Current Profiler (ADCP) data obtained during (ACCP) Atlantic Climate Change Program cruises in the western subtropical and tropical Atlantic in January, June and September 1991.

  11. Architectural-acoustics consulting

    NASA Astrophysics Data System (ADS)

    Hoover, Anthony K.

    2004-05-01

    Consulting involves both the science of acoustics and the art of communication, requiring an array of inherent and created skills. Perhaps because consulting on architectural acoustics is a relatively new field, there is a remarkable variety of career paths, all influenced by education, interest, and experience. Many consultants juggle dozens of chargeable projects at a time, not to mention proposals, seminars, teaching, articles, business concerns, and professional-society activities. This paper will discuss various aspects of career paths, projects, and clients as they relate to architectural-acoustics consulting. The intended emphasis will be considerations for those who may be interested in such a career, noting that consultants generally seem to thrive on the numerous challenges.

  12. Students' community health service delivery: experiences of involved parties.

    PubMed

    Greeff, M; van der Walt, E; Strydom, C; Wessels, C; Schutte, P J

    2009-03-01

    For several years the School of Nursing Science and the School of Psychosocial Behavioural Science, of a specific university, have been offering health care services in response to some of the health needs of a disadvantaged community as part of their students' experiential learning. However, these health care services were rendered independently by these two schools, implying that no feedback system existed to evaluate the worth and quality of these student-rendered health care services. The objectives of this research were to explore and describe the experiences of senior nursing and social work students, the experiences of health service delivery organisations concerned and the experiences of the disadvantaged community members receiving such health care services, as well as to investigate which communication models were apparent with regard to the major factors within health communication. An exploratory descriptive qualitative research design was used. Focus group discussions were held, interviews were conducted and field notes taken. Focus group discussions and interviews were transcribed and analysed by the research team to determine themes and sub-themes using the open coding technique. The results of the three groups showed similarities. The health service delivery organisations also identified a communication barrier, although the students were prepared to bridge it. The health service delivery organisations and the community felt positive towards the students and what they offered to the organisations and to the patients. A greater need for multi-disciplinary team work was recognised by al parties concerned. Recommendations focus on improved student accompaniment by lecturers; extending health care delivery to include a multi-disciplinary team approach by students; as well as improving the delivery of health care services.

  13. Involvement of a community in schistosomiasis control: a Kenyan experience.

    PubMed

    Katsivo, M N; Muthami, L N; Kimani, S; Karama, M; Kingori, F

    1993-08-01

    This paper illustrates how community participation was achieved in a study that was carried out between 1983-1988 whose general objective was to reduce the transmission of schistosomiasis in a rice irrigation scheme in Kenya. A community of 2,219 people was mobilized through health education, to effect changes in behaviour regarding water contact, water use and faecal disposal. Health education, alternative water sources, latrines and mass chemotherapy with praziquantel were the schistosomiasis control strategies utilized in this study. By the end of 2 years, the canals were cleared of their thick vegetation, water, sanitation, bathing and washing facilities were constructed, water contact with infective waters was reduced, faecal contamination of water was reduced, the people's knowledge on schistosomiasis increased and the rate and intensity of schistosomiasis infection was reduced. The study demonstrated that it is possible to fully involve the community in disease control efforts.

  14. Characterization of blocks impacts from acoustic emissions: insights from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Farin, Maxime; Mangeney, Anne; de Rosny, Julien; Toussaint, Renaud; Shapiro, Nikolaï

    2014-05-01

    Rockfalls, debris flows and rock avalanches represent a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very dangerous. Recent studies showed that gravitational instabilities can be detected and characterized (volume, duration,...) thanks to the seismic signal they generate. In an avalanche, individual block bouncing and rolling on the ground are expected to generated signals of higher frequencies than the main flow spreading. The identification of the time/frequency signature of individual blocks in the recorded signal remains however difficult. Laboratory experiments were conducted to investigate the acoustic signature of diverse simple sources corresponding to grains falling over thin plates of plexiglas and glass and over rock blocks. The elastic energy emitted by a single bouncing bead into the support was first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. We obtained simple scaling laws relating the impactor characteristics (size, height of fall, material,...) to the elastic energy and spectral content. Next, we consider the collapse of granular columns made of steel spherical beads onto hard substrates. Initially, these columns were held by a magnetic field allowing to suppress suddenly the cohesion between the beads, and thus to minimize friction effects that would arise from side walls. We varied systematically the column volume, the column aspect ratio (height over length) and the grain size. This is shown to affect the signal envelope and frequency content. In the experiments, accelerometers (1 Hz to 56 kHz) were used to record the signals in a wide frequency range. The experiments were also monitored optically using fast cameras. Eventually, we looked at what types of features in the signal are affected by individual impacts, rolling of beads or by the large scale geometry of the avalanche.

  15. Multibiological life support system experiments with humans partially involved

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Tong, Ling; Li, Ming; Hu, Dawei; Fu, Yuming; He, Wenting; Hu, Enzhu

    To establish bioregenerative life support system in lunar or mars bases in the future, manned stimulation experiments including several kinds of creatures are needed to be conducted first. Gas exchange relation, element transfer and transformation principles, etc. between human beings and the multibiological system composed of plants, animals, Chlorella vulgaris and so on must be investigated in order to place different organisms with appropriate numbers and proportions. This research cultivated lettuce (Lactuca sativa L.) and silkworm (Bombyx Mori L.) in the Closed Integrative Cultivating System (CICS) of the Integrative Experimental Sys-tem (IES) with Chlorella vulgaris cultivated in the Plate Photo Bioreactor (PPB) of the IES. Gas exchange between testers and the IES were conducted periodically. The automotive control system of the PPB changed the illumination intensity of the photo bioreactor according to the CO2 concentration in the IES to make CO2 /O2 in the system maintain at stable levels by regu-lating the photosynthesis of alga. The conveyor-type cultivation method which was harvesting the biggest batch of lettuce and silkworms through the mass exchange chamber of IES every four days and transferring the smallest batch of lettuce and silkworms into the system; carrying certain amount of alga liquid out of the bioreactor every day with nutrient liquid replenished into the system was implemented in the experiments. In terms of gas circulation, CO2 /O2 concentration changes in the system with trace gas contaminants (CH4 , NH3 and C2 H4 ) were measured. As to the mass transfer and transformation, element (C, H, O, N) contents, height, crown width and biomasses of lettuce in different developing stages, silkworms' bioconversion rates, alga's biomass changes, the amount and community change trends of the microorganism in different positions of the system, the quality of condensates gained under different running conditions and so on were studied. Results showed

  16. Critical issues encountered in experiments and measurements involving optical turbulence

    NASA Astrophysics Data System (ADS)

    Eaton, Frank D.

    2007-02-01

    The successful design and operation of high energy laser (HEL) and laser communication systems require a comprehensive and thorough knowledge of the real turbulent atmosphere coupled with high-fidelity realistic laser beam propagation models. To date, modeling and simulation of laser beam propagation through atmospheric turbulence have relied upon a traditional theoretical basis that assumes the existence of homogeneous, isotropic, stationary, and Kolmogorov turbulence. The real impact of the refractive index structure parameter ( C2 n ) on laser beam propagation including effects of non-classical turbulence as well as inner (l °) and outer scale (L °) effects will be examined. Observations clearly show turbulence is often layered and is produced by wave activity and episodic events such as Kelvin-Helmholtz instabilities. Other critical turbulence issues involve the relationship between mechanical and optical turbulence and the effect of path variability of turbulence and inner scale on optical turbulence parameters over long paths. These issues will be examined from data obtained from five systems: a) a new measurement platform using a free-flying balloon that lifts a ring with a boom upon which are mounted several fine wire (1-μm diameter) sensors to measure high-speed temperature and velocity fluctuations, b) a new system using a kite/tethered blimp platform that obtains both profile and measurements at a fixed altitude over time, c) a 50 MHz radar at Vandenberg Air Force Base that senses at high temporal and spatial resolution to 20 km ASL, d) an instrumented aircraft system, and e) a suite of optical systems. The first four systems all provide estimates of C2 n , the eddy dissipation rate (\\Vegr), l ° and L °. Methods of calibration and problems of interpreting results from the measurement systems are discussed.

  17. Effect of Anisotropic Velocity Structure on Acoustic Emission Source Location during True-Triaxial Deformation Experiments

    NASA Astrophysics Data System (ADS)

    Ghofrani Tabari, Mehdi; Goodfellow, Sebastian; Young, R. Paul

    2016-04-01

    Although true-triaxial testing (TTT) of rocks is now more extensive worldwide, stress-induced heterogeneity due to the existence of several loading boundary effects is not usually accounted for and simplified anisotropic models are used. This study focuses on the enhanced anisotropic velocity structure to improve acoustic emission (AE) analysis for an enhanced interpretation of induced fracturing. Data from a TTT on a cubic sample of Fontainebleau sandstone is used in this study to evaluate the methodology. At different stages of the experiment the True-Triaxial Geophysical Imaging Cell (TTGIC), armed with an ultrasonic and AE monitoring system, performed several velocity surveys to image velocity structure of the sample. Going beyond a hydrostatic stress state (poro-elastic phase), the rock sample went through a non-dilatational elastic phase, a dilatational non-damaging elasto-plastic phase containing initial AE activity and finally a dilatational and damaging elasto-plastic phase up to the failure point. The experiment was divided into these phases based on the information obtained from strain, velocity and AE streaming data. Analysis of the ultrasonic velocity survey data discovered that a homogeneous anisotropic core in the center of the sample is formed with ellipsoidal symmetry under the standard polyaxial setup. Location of the transducer shots were improved by implementation of different velocity models for the sample starting from isotropic and homogeneous models going toward anisotropic and heterogeneous models. The transducer shot locations showed a major improvement after the velocity model corrections had been applied especially at the final phase of the experiment. This location improvement validated our velocity model at the final phase of the experiment consisting lower-velocity zones bearing partially saturated fractures. The ellipsoidal anisotropic velocity model was also verified at the core of the cubic rock specimen by AE event location of

  18. The Chemistry Involved in the Preparation of a Paint Pigment: An Experiment for the Freshman Laboratory

    ERIC Educational Resources Information Center

    Daines, Terri L.; Morse, Karen W.

    1976-01-01

    Describes an experiment that demonstrates the following principles and reactions: amphoterism, oxidation-reduction, equilibrium dependence on pH, solubility, and polymerization. The experiment involves the oxidation of chromium and the precipitation of a chromate salt. (MLH)

  19. Acoustic flight test experience with the XV-15 Tiltrotor aircraft with the Advanced Technology Blade (ATB)

    NASA Technical Reports Server (NTRS)

    Hoad, Danny R.; Conner, David A.; Rutledge, Charles K.

    1992-01-01

    An acoustic model that predicts the discrete frequency noise characteristics of helicopter rotors has been utilized in an analysis to help identify source characteristics. This technique incorporated a NASA Langley developed acoustic prediction technique, and a simplified flow field model to account for rotor wake reingestion in hover. The vehicle rotor system was modified to include the ATBs that were designed to provide for higher operating weights and improved maneuver load factor in helicopter and transition modes of operation.

  20. PoroTomo Subtask 3.2 Data files from the Distributed Acoustic Sensing experiment at Garner Valley, California

    DOE Data Explorer

    Chelsea Lancelle

    2013-09-11

    In September 2013, an experiment using Distributed Acoustic Sensing (DAS) was conducted at Garner Valley, a test site of the University of California Santa Barbara (Lancelle et al., 2014). This submission includes all DAS data recorded during the experiment. The sampling rate for all files is 1000 samples per second. Any files with the same filename but ending in _01, _02, etc. represent sequential files from the same test. Locations of the sources are plotted on the basemap in GDR submission 481, titled: "PoroTomo Subtask 3.2 Sample data from a Distributed Acoustic Sensing experiment at Garner Valley, California (PoroTomo Subtask 3.2)." Lancelle, C., N. Lord, H. Wang, D. Fratta, R. Nigbor, A. Chalari, R. Karaulanov, J. Baldwin, and E. Castongia (2014), Directivity and Sensitivity of Fiber-Optic Cable Measuring Ground Motion using a Distributed Acoustic Sensing Array (abstract # NS31C-3935), AGU Fall Meeting. 
https://agu.confex.com/agu/fm1/meetingapp.cgi#Paper/19828 The e-poster is available at: https://agu.confex.com/data/handout/agu/fm14/Paper_19828_handout_696_0.pdf

  1. Acoustic simulations with a ray-tracing program: Reporting an experience

    NASA Astrophysics Data System (ADS)

    Granado, Milton V., Jr.

    2002-11-01

    The possibility of exporting to ray-tracing type programs the geometry generated by Auto-Cad, is very appealing for the architect who wishes to simulate the acoustic behavior of a room. It was found that a good knowledge of room acoustic is necessary for the selection of the program parameters and the objective acoustical measures outputted by the program for the assessment of the required acoustical quality. There is scarce information on the absorption coefficients of lining materials, but it is on the choice of the diffusion coefficients where lie the greatest uncertainties. Because of the considerable impact that these data have on the computational results, the user may feel insecure about the results of his efforts. Therefore it is advisable that trained personnel participate in the efficient use of this computational tool. It was found however that one form of the output of the program, that in which the acoustical parameters are color mapped, have qualitatively corroborated speech intelligibility results objectively measured in the field. (To be presented in Portuguese.)

  2. Sample data from a Distributed Acoustic Sensing experiment at Garner Valley, California (PoroTomo Subtask 3.2)

    DOE Data Explorer

    Lancelle, Chelsea

    2013-09-10

    In September 2013, an experiment using Distributed Acoustic Sensing (DAS) was conducted at Garner Valley, a test site of the University of California Santa Barbara (Lancelle et al., 2014). This submission includes one 45 kN shear shaker (called “large shaker” on the basemap) test for three different measurement systems. The shaker swept from a rest, up to 10 Hz, and back down to a rest over 60 seconds. Lancelle, C., N. Lord, H. Wang, D. Fratta, R. Nigbor, A. Chalari, R. Karaulanov, J. Baldwin, and E. Castongia (2014), Directivity and Sensitivity of Fiber-Optic Cable Measuring Ground Motion using a Distributed Acoustic Sensing Array (abstract # NS31C-3935), AGU Fall Meeting. https://agu.confex.com/agu/fm1/meetingapp.cgi#Paper/19828 The e-poster is available at: https://agu.confex.com/data/handout/agu/fm14/Paper_19828_handout_696_0.pdf

  3. Investigation of acoustic gravity waves created by anomalous heat sources: experiments and theoretical analysis

    NASA Astrophysics Data System (ADS)

    Pradipta, R.; Lee, M. C.

    2013-07-01

    We have been investigating high-power radio wave-induced acoustic gravity waves (AGWs) at Gakona, Alaska, using the High-frequency Active Aurora Research Program (HAARP) heating facility (i.e. HF heater) and extensive diagnostic instruments. This work was aimed at performing a controlled study of the space plasma turbulence triggered by the AGWs originating from anomalous heat sources, as observed in our earlier experiments at Arecibo, Puerto Rico (Pradipta 2007 MS Thesis MIT Press, Cambridge, MA). The HF heater operated in continuous wave (CW) O-mode can heat ionospheric plasmas effectively to yield a depleted magnetic flux tube as rising plasma bubbles (Lee et al 1998 Geophys. Res. Lett. 25 579). Two processes are responsible for the depletion of the magnetic flux tube: (i) thermal expansion and (ii) chemical reactions caused by heated ions. The depleted plasmas create large density gradients that can augment spread F processes via generalized Rayleigh-Taylor instabilities (Lee et al 1999 Geophys. Res. Lett. 26 37). It is thus expected that the temperature of neutral particles in the heated ionospheric region can be increased. Such a heat source in the neutral atmosphere may potentially generate AGWs in the form of traveling ionospheric plasma disturbances (TIPDs). We should point out that these TIPDs have features distinctively different from electric and magnetic field (ExB) drifts of HF wave-induced large-scale non-propagating plasma structures. Moreover, it was noted in our recent study of naturally occurring AGW-induced TIDs that only large-scale AGWs can propagate upward to reach higher altitudes. Thus, in our Gakona experiments we select optimum heating schemes for HF wave-induced AGWs that can be distinguished from the naturally occurring ones. The generation and propagation of AGWs are monitored by MUIR (Modular Ultra high-frequency Ionospheric Radar), Digisonde and GPS/low-earth-orbit satellites. Our theoretical and experimental studies have shown that

  4. Acoustic Characterization of Fluorinert FC-43 Liquid with Helium Gas Bubbles: Numerical Experiments

    DOE PAGES

    Vanhille, Christian; Pantea, Cristian; Sinha, Dipen N.

    2017-01-01

    In this work, we define the acoustic characteristics of a biphasic fluid consisting of static helium gas bubbles in liquid Fluorinert FC-43 and study the propagation of ultrasound of finite amplitudes in this medium. Very low sound speed and high sound attenuation are found, in addition to a particularly high acoustic nonlinear parameter. This result suggests the possibility of using this medium as a nonlinear enhancer in various applications. In particular, parametric generation of low ultrasonic frequencies is studied in a resonator cavity as a function of driving pressure showing high conversion efficiency. This work suggests that this medium couldmore » be used for applications such as parametric arrays, nondestructive testing, diagnostic medicine, sonochemistry, underwater acoustics, and ultrasonic imaging and to boost the shock formation in fluids.« less

  5. Thermo acoustic study of carbon nanotubes in near and far field: Theory, simulation, and experiment

    NASA Astrophysics Data System (ADS)

    Asadzadeh, S. S.; Moosavi, A.; Huynh, C.; Saleki, O.

    2015-03-01

    Carbon nanotube webs exhibit interesting properties when used as thermo-acoustic projectors. This work studies thermo-acoustic effect of these sound sources both in near and far field regions. Based on two alternative forms of the energy equation, we have developed a straightforward formula for calculation of pressure field, which is consistent with experimental data in far field. Also we have solved full 3-D governing equations using numerical methods. Our three-dimensional simulation and experimental data show pressure waves are highly affected by dimensions of sound sources in near field due to interference effects. However, generation of sound waves in far field is independent of projectors area surface. Energy analysis for free standing Thermo-Acoustic (TA) sound sources show that aerogel TA sound sources like CNT based projectors could act more efficiently compared to the other sources in delivering more than 75% of alternative input energy to the medium gas up to a frequency of 1 MHz.

  6. Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

    SciTech Connect

    Dai, Xiwen; Jing, Xiaodong Sun, Xiaofeng

    2015-05-15

    The acoustic resonance in a Helmholtz resonator excited by a low Mach number grazing flow is studied theoretically. The nonlinear numerical model is established by coupling the vortical motion at the cavity opening with the cavity acoustic mode through an explicit force balancing relation between the two sides of the opening. The vortical motion is modeled in the potential flow framework, in which the oscillating motion of the thin shear layer is described by an array of convected point vortices, and the unsteady vortex shedding is determined by the Kutta condition. The cavity acoustic mode is obtained from the one-dimensional acoustic propagation model, the time-domain equivalent of which is given by means of a broadband time-domain impedance model. The acoustic resistances due to radiation and viscous loss at the opening are also taken into account. The physical processes of the self-excited oscillations, at both resonance and off-resonance states, are simulated directly in the time domain. Results show that the shear layer exhibits a weak flapping motion at the off-resonance state, whereas it rolls up into large-scale vortex cores when resonances occur. Single and dual-vortex patterns are observed corresponding to the first and second hydrodynamic modes. The simulation also reveals different trajectories of the two vortices across the opening when the first and second hydrodynamic modes co-exist. The strong modulation of the shed vorticity by the acoustic feedback at the resonance state is demonstrated. The model overestimates the pressure pulsation amplitude by a factor 2, which is expected to be due to the turbulence of the flow which is not taken into account. The model neglects vortex shedding at the downstream and side edges of the cavity. This will also result in an overestimation of the pulsation amplitude.

  7. An impulsive source with variable output and stable bandwidth for underwater acoustic experiments.

    PubMed

    McNeese, Andrew R; Wilson, Preston S; Sagers, Jason D; Knobles, David P

    2014-07-01

    The Combustive Sound Source (CSS) is being developed as an environmentally friendly source to be used in ocean acoustics research and surveys. It has the ability to maintain the same wide bandwidth signal over a 20 dB drop in source level. The CSS consists of a submersible combustion chamber filled with a fuel/oxidizer mixture. The mixture is ignited and the ensuing combustion and bubble activity radiates an impulsive, thus broadband, acoustic pulse. The ability to control pulse amplitude while maintaining bandwidth is demonstrated.

  8. Comparison of Computational Aeroacoustics Prediction of Acoustic Transmission Through a 3D Stator with Experiment

    NASA Technical Reports Server (NTRS)

    Hixon, Ray; Envia, Edmane; Dahl, Milo; Sutliff, Daniel

    2014-01-01

    In this paper, numerical predictions of acoustic transmission through a 3D stator obtained using the NASA BASS code are compared with experimentally measured data. The influence of vane count and stagger as well as frequency and mode order on the transmission loss is investigated. The data-theory comparisons indicate that BASS can predict all the important trends observed in the experimental data.

  9. Comparison of Computational Aeroacoustics Prediction of Acoustic Transmission Through a 3D Stator With Experiment

    NASA Technical Reports Server (NTRS)

    Hixon, Ray; Envia, Edmane; Dahl, Milo; Sutliff, Daniel L.

    2014-01-01

    In this paper, numerical predictions of acoustic transmission through a 3D stator obtained using the NASA BASS code are compared with experimentally measured data. The influence of vane count and stagger as well as frequency and mode order on the transmission loss is investigated. The data-theory comparisons indicate that BASS can predict all the important trends observed in the experimental data.

  10. 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.

  11. Localization of short-range acoustic and seismic wideband sources: Algorithms and experiments

    NASA Astrophysics Data System (ADS)

    Stafsudd, J. Z.; Asgari, S.; Hudson, R.; Yao, K.; Taciroglu, E.

    2008-04-01

    We consider the determination of the location (source localization) of a disturbance source which emits acoustic and/or seismic signals. We devise an enhanced approximate maximum-likelihood (AML) algorithm to process data collected at acoustic sensors (microphones) belonging to an array of, non-collocated but otherwise identical, sensors. The approximate maximum-likelihood algorithm exploits the time-delay-of-arrival of acoustic signals at different sensors, and yields the source location. For processing the seismic signals, we investigate two distinct algorithms, both of which process data collected at a single measurement station comprising a triaxial accelerometer, to determine direction-of-arrival. The direction-of-arrivals determined at each sensor station are then combined using a weighted least-squares approach for source localization. The first of the direction-of-arrival estimation algorithms is based on the spectral decomposition of the covariance matrix, while the second is based on surface wave analysis. Both of the seismic source localization algorithms have their roots in seismology; and covariance matrix analysis had been successfully employed in applications where the source and the sensors (array) are typically separated by planetary distances (i.e., hundreds to thousands of kilometers). Here, we focus on very-short distances (e.g., less than one hundred meters) instead, with an outlook to applications in multi-modal surveillance, including target detection, tracking, and zone intrusion. We demonstrate the utility of the aforementioned algorithms through a series of open-field tests wherein we successfully localize wideband acoustic and/or seismic sources. We also investigate a basic strategy for fusion of results yielded by acoustic and seismic arrays.

  12. Ultrasound imparted air-recoil resonance (UIAR) method for acoustic power estimation: theory and experiment.

    PubMed

    Kaiplavil, Sreekumar; Rivens, Ian; ter Haar, Gail

    2013-07-01

    Ultrasound imparted air-recoil resonance (UIAR), a new method for acoustic power estimation, is introduced with emphasis on therapeutic high-intensity focused ultrasound (HIFU) monitoring applications. Advantages of this approach over existing practices include fast response; electrical and magnetic inertness, and hence MRI compatibility; portability; high damage threshold and immunity to vibration and interference; low cost; etc. The angle of incidence should be fixed for accurate measurement. However, the transducer-detector pair can be aligned in any direction with respect to the force of gravity. In this sense, the operation of the device is orientation independent. The acoustic response of a pneumatically coupled pair of Helmholtz resonators, with one of them acting as the sensor head, is used for the estimation of acoustic power. The principle is valid in the case of pulsed/ burst as well as continuous ultrasound exposure, the former being more sensitive and accurate. An electro-acoustic theory has been developed for describing the dynamics of pressure flow and resonance in the system considering various thermo- viscous loss mechanisms. Experimental observations are found to be in agreement with theoretical results. Assuming the window damage threshold (~10 J·mm(-2)) and accuracy of RF power estimation are the upper and lower scale-limiting factors, the performance of the device was examined for an RF power range of 5 mW to 100 W with a HIFU transducer operating at 1.70 MHz, and an average nonlinearity of ~1.5% was observed. The device is also sensitive to sub-milliwatt powers. The frequency response was analyzed at 0.85, 1.70, 2.55, and 3.40 MHz and the results are presented with respective theoretical estimates. Typical response time is in the millisecond regime. Output drift is about 3% for resonant and 5% for nonresonant modes. The principle has been optimized to demonstrate a general-purpose acoustic power meter.

  13. Embedding a Recovery Orientation into Neuroscience Research: Involving People with a Lived Experience in Research Activity.

    PubMed

    Stratford, Anthony; Brophy, Lisa; Castle, David; Harvey, Carol; Robertson, Joanne; Corlett, Philip; Davidson, Larry; Everall, Ian

    2016-03-01

    This paper highlights the importance and value of involving people with a lived experience of mental ill health and recovery in neuroscience research activity. In this era of recovery oriented service delivery, involving people with the lived experience of mental illness in neuroscience research extends beyond their participation as "subjects". The recovery paradigm reconceptualises people with the lived experience of mental ill health as experts by experience. To support this contribution, local policies and procedures, recovery-oriented training for neuroscience researchers, and dialogue about the practical applications of neuroscience research, are required.

  14. Computationally efficient parabolic equation solutions to seismo-acoustic problems involving thin or low-shear elastic layers.

    PubMed

    Metzler, Adam M; Collis, Jon M

    2013-04-01

    Shallow-water environments typically include sediments containing thin or low-shear layers. Numerical treatments of these types of layers require finer depth grid spacing than is needed elsewhere in the domain. Thin layers require finer grids to fully sample effects due to elasticity within the layer. As shear wave speeds approach zero, the governing system becomes singular and fine-grid spacing becomes necessary to obtain converged solutions. In this paper, a seismo-acoustic parabolic equation solution is derived utilizing modified difference formulas using Galerkin's method to allow for variable-grid spacing in depth. Propagation results are shown for environments containing thin layers and low-shear layers.

  15. The Ability to Structure Acoustic Material as a Measure of Musical Aptitude. 4. Experiences with Modifications of the Acoustic Structuring Test. Research Bulletin. No. 51.

    ERIC Educational Resources Information Center

    Karma, Kai

    Four new versions of an acoustic structuring test were developed, administered, and analyzed in order to produce better tests and to contribute to better understanding of the abilities measured by these tests. The tests consist of tape recordings of patterns of musical notes played on an electric organ or an acoustic guitar. Item analyses and…

  16. Technically Speaking: On the Structure and Experience of Interaction Involving Augmentative Alternative Communications

    ERIC Educational Resources Information Center

    Engelke, Christopher Robert

    2013-01-01

    Technically Speaking: On the Structure and Experience of Interaction Involving Augmentative Alternative Communications examines the ways that communication is structured and experienced by looking at interactions involving augmented communicators--people with severe speech disabilities who use forms of assistive technology in order to communicate…

  17. Analysis of an existing experiment on the interaction of acoustic waves with a laminar boundary layer

    NASA Technical Reports Server (NTRS)

    Schopper, M. R.

    1982-01-01

    The hot-wire anemometer amplitude data contained in the 1977 report of P. J. Shapiro entitled, ""The Influence of Sound Upon Laminar Boundary'' were reevaluated. Because the low-Reynolds number boundary layer disturbance data were misinterpreted, an effort was made to improve the corresponding disturbance growth rate curves. The data are modeled as the sum of upstream and downstream propagating acoustic waves and a wave representing the Tollmien-Schlichting (TS) wave. The amplitude and phase velocity of the latter wave were then adjusted so that the total signal reasonably matched the amplitude and phase angle hot-wire data along the plate laminar boundary layer. The revised rates show growth occurring further upstream than Shapiro found. It appears that the premature growth is due to the adverse pressure gradient created by the shape of the plate. Basic elements of sound propagation in ducts and the experimental and theoretical acoustic-stability literature are reviewed.

  18. Scanning electron acoustic microscopy of residual stresses in ceramics: Theory and experiment

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Qian, Menglu

    1992-01-01

    Several reviews have highlighted a number of applications of scanning electron acoustic microscopy (SEAM) to metals and semiconductors which show that SEAM can provide new information on surface and near-surface features of such materials, but there have been few studies attempting to determine the capabilities of SEAM for characterizing ceramic materials. We have recently observed image contrast in SEAM from residual stress fields induced in brittle materials by Vickers indentations that is strongly dependent on the electron beam chopping frequency. We have also recently developed a three-dimensional mathematical model of signal generation and contrast in SEAM, appropriate to the brittle materials studied, that we use as a starting point in this paper for modeling the effect of residual stress fields on the generated electron acoustic signal. The influence of the electron beam chopping frequency is also considered under restrictive assumptions.

  19. Horizontal Anisotropy and Seasonal Variation of Acoustic Fluctuations Observed During the 20102011 Philippine Sea Experiment

    DTIC Science & Technology

    2015-12-01

    No. 0704–0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for...22202- 4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington, DC 20503. 1. AGENCY USE ONLY (Leave blank...ABSTRACT (maximum 200 words) The anisotropic ocean environment will lead to variability of ocean acoustic travel time . The variability of

  20. Acoustic Behavior of Halobacterium salinarum Gas Vesicles in the High-Frequency Range: Experiments and Modeling.

    PubMed

    Cherin, Emmanuel; Melis, Johan M; Bourdeau, Raymond W; Yin, Melissa; Kochmann, Dennis M; Foster, F Stuart; Shapiro, Mikhail G

    2017-03-01

    Gas vesicles (GVs) are a new and unique class of biologically derived ultrasound contrast agents with sub-micron size whose acoustic properties have not been fully elucidated. In this study, we investigated the acoustic collapse pressure and behavior of Halobacterium salinarum gas vesicles at transmit center frequencies ranging from 12.5 to 27.5 MHz. The acoustic collapse pressure was found to be above 550 kPa at all frequencies, nine-fold higher than the critical pressure observed under hydrostatic conditions. We illustrate that gas vesicles behave non-linearly when exposed to ultrasound at incident pressure ranging from 160 kPa to the collapse pressure and generate second harmonic amplitudes of -2 to -6 dB below the fundamental in media with viscosities ranging from 0.89 to 8 mPa·s. Simulations performed using a Rayleigh-Plesset-type model accounting for buckling and a dynamic finite-element analysis suggest that buckling is the mechanism behind the generation of harmonics. We found good agreement between the level of second harmonic relative to the fundamental measured at 20 MHz and the Rayleigh-Plesset model predictions. Finite-element simulations extended these findings to a non-spherical geometry, confirmed that the acoustic buckling pressure corresponds to the critical pressure under hydrostatic conditions and support the hypothesis of limited gas flow across the GV shell during the compression phase in the frequency range investigated. From simulations, estimates of GV bandwidth-limited scattering indicate that a single GV has a scattering cross section comparable to that of a red blood cell. These findings will inform the development of GV-based contrast agents and pulse sequences to optimize their detection with ultrasound.

  1. The Northern Experience of Street-Involved Youth: A Narrative Inquiry

    ERIC Educational Resources Information Center

    George, Serena D.; O'Neill, Linda K.

    2011-01-01

    This research explored the experiences of 8 street-involved youth (4 male, 4 female) between the ages of 20 and 27 living in north-central British Columbia. The analysis was carried out in 3 phases based on the narrative approach developed by Lieblich, Tuval-Mashiach, and Zilber (1998). The narratives represented the holistic experiences of the…

  2. An Inorganic Laboratory Experiment Involving Photochemistry, Liquid Chromatography, and Infrared Spectroscopy.

    ERIC Educational Resources Information Center

    Post, Elroy W.

    1980-01-01

    Presents an experiment involving photochemical legand displacement on a metal carbonyl, separation of the product mixture by chromotography, and identification of the components by use of infrared spectroscopy and group theory. The chromatography and spectroscopy are combined as complementary tools in this experiment. (Author/JN)

  3. Educational Support System for Experiments Involving Construction of Sound Processing Circuits

    ERIC Educational Resources Information Center

    Takemura, Atsushi

    2012-01-01

    This paper proposes a novel educational support system for technical experiments involving the production of practical electronic circuits for sound processing. To support circuit design and production, each student uses a computer during the experiments, and can learn circuit design, virtual circuit making, and real circuit making. In the…

  4. Community College Transfer Student Involvement Experiences at a Selective, Private Four-Year University

    ERIC Educational Resources Information Center

    Castillo, Carolina

    2011-01-01

    This dissertation tested the constructs of academic and social involvement and adjustment on grades as a pathway to explain community college transfer student experiences beyond the concept of transfer shock. The study contributes to the growing body of literature on Latina(o) community college transfer student experiences with the application of…

  5. Topics in Chemical Instrumentation: XCVIII. Experiments Involving Thermal Methods of Analysis for Undergraduate Chemistry Laboratories.

    ERIC Educational Resources Information Center

    Ewing, Galen W., Ed.

    1978-01-01

    Explains some experiments involving thermal methods of analysis for undergraduate chemistry laboratories. Some experiments are: (1) the determination of the density and degree of crystallinity of a polymer; and (2) the determination of the specific heat of a nonvolatile compound. (HM)

  6. Sound propagation in and radiation from acoustically lined flow ducts: A comparison of experiment and theory

    NASA Technical Reports Server (NTRS)

    Plumblee, H. E., Jr.; Dean, P. D.; Wynne, G. A.; Burrin, R. H.

    1973-01-01

    The results of an experimental and theoretical study of many of the fundamental details of sound propagation in hard wall and soft wall annular flow ducts are reported. The theory of sound propagation along such ducts and the theory for determining the complex radiation impedance of higher order modes of an annulus are outlined, and methods for generating acoustic duct modes are developed. The results of a detailed measurement program on propagation in rigid wall annular ducts with and without airflow through the duct are presented. Techniques are described for measuring cut-on frequencies, modal phase speed, and radial and annular mode shapes. The effects of flow velocity on cut-on frequencies and phase speed are measured. Comparisons are made with theoretical predictions for all of the effects studies. The two microphone method of impedance is used to measure the effects of flow on acoustic liners. A numerical study of sound propagation in annular ducts with one or both walls acoustically lined is presented.

  7. Perception of Male Caller Identity in Koalas (Phascolarctos cinereus): Acoustic Analysis and Playback Experiments

    PubMed Central

    Charlton, Benjamin D.; Ellis, William A. H.; McKinnon, Allan J.; Brumm, Jacqui; Nilsson, Karen; Fitch, W. Tecumseh

    2011-01-01

    The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels. PMID:21633499

  8. Scanning electron acoustic microscopy of residual stresses in ceramics - Theory and experiment

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Qian, Menglu

    1992-01-01

    The paper presents a three-dimensional mathematical model of signal generation and contrast in brittle materials and uses the model to simulate the effect of residual stress fields on the scanning electron acoustic microscopy (SEAM)-generated electron acoustic signal. According to the model, a positive (tensile) strain produces an increase in the output signal, whereas a negative (compressive) strain produces a decrease in the ouput signal. Dark field contrast conditions occur at a chopping frequency at which V2 - V1 is greater than 0 (where V2 = V is the SEAM output in a region of residual stresses, and V1 is the output in a stress-free region of the sample). Under ideal conditions (maximum contrast) V1 approaches zero. It was found that tensile strains of the order 0.2-0.3 percent, possible in brittle materials, would produce a variation of the acoustic output signal of the order 10 nV (about 1 percent), well within the image contrast and signal processing capability of the SEAM electronics.

  9. Perception of male caller identity in Koalas (Phascolarctos cinereus): acoustic analysis and playback experiments.

    PubMed

    Charlton, Benjamin D; Ellis, William A H; McKinnon, Allan J; Brumm, Jacqui; Nilsson, Karen; Fitch, W Tecumseh

    2011-01-01

    The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels.

  10. Acoustic data analysis and scenario over watch from an aerostat at the NATO SET-153 field experiment

    NASA Astrophysics Data System (ADS)

    Reiff, Christian; Scanlon, Michael

    2012-06-01

    The purpose of the NATO SET-153 field experiment was to provide an opportunity to demonstrate multiple sensor technologies in an urban environment and determine integration capabilities for future development. The Army Research Laboratory (ARL) experimental aerostat was used primarily as a persistent over watch capability as a substitute for a UAV. Continuous video was recorded on the aerostat and segments of video were captured of the scenarios on the ground that the camera was following manually. Some of the segments showing scenario activities will be presented. The captured pictures and video frames have telemetry in the headers that provides the UTM time and the Inertial Navigation System (INS) GPS location and the inertial roll, pitch, and yaw as well as the camera gimbal pan and tilt angles. The timing is useful to synchronize the images with the scenario events providing activity ground truth. The INS, GPS, and camera gimbal angle values can be used with the acoustic solution for the location of a sound source to determine the relative accuracy of the solution if the camera is pointed at the sound source. This method will be confirmed by the use of a propane cannon whose GPS location is logged. During the field experiment, other interesting acoustic events such as vehicle convoys, platoon level firefights with vehicles using blanks, and a UAV helicopter were recorded and will be presented in a quick analysis.

  11. Wavelet preprocessing of acoustic signals

    NASA Astrophysics Data System (ADS)

    Huang, W. Y.; Solorzano, M. R.

    1991-12-01

    This paper describes results using the wavelet transform to preprocess acoustic broadband signals in a system that discriminates between different classes of acoustic bursts. This is motivated by the similarity between the proportional bandwidth filters provided by the wavelet transform and those found in biological hearing systems. The experiment involves comparing statistical pattern classifier effects of wavelet and FFT preprocessed acoustic signals. The data used was from the DARPA Phase 1 database, which consists of artificially generated signals with real ocean background. The results show that the wavelet transform did provide improved performance when classifying in a frame-by-frame basis. The DARPA Phase 1 database is well matched to proportional bandwidth filtering; i.e., signal classes that contain high frequencies do tend to have shorter duration in this database. It is also noted that the decreasing background levels at high frequencies compensate for the poor match of the wavelet transform for long duration (high frequency) signals.

  12. Female rhesus macaques discriminate unfamiliar paternal sisters in playback experiments: support for acoustic phenotype matching

    PubMed Central

    Pfefferle, Dana; Ruiz-Lambides, Angelina V.; Widdig, Anja

    2014-01-01

    Widespread evidence exists that when relatives live together, kinship plays a central role in shaping the evolution of social behaviour. Previous studies showed that female rhesus macaques (Macaca mulatta) recognize familiar maternal kin using vocal cues. Recognizing paternal kin might, however, be more difficult as rhesus females mate promiscuously during the possible conception period, most probably concealing paternity. Behavioural observations indicate that semi free-ranging female rhesus macaques prefer to associate with their paternal half-sisters in comparison to unrelated females within the same group, particularly when born within the same age cohort. However, the cues and mechanism/s used in paternal kin discrimination remain under debate. Here, we investigated whether female rhesus macaques use the acoustic modality to discriminate between paternal half-sisters and non-kin, and tested familiarity and phenotype matching as the underlying mechanisms. We found that test females responded more often to calls of paternal half-sisters compared with calls of unrelated females, and that this discrimination ability was independent of the level of familiarity between callers and test females, which provides, to our knowledge, the first evidence for acoustic phenotype matching. Our study strengthens the evidence that female rhesus macaques can recognize their paternal kin, and that vocalizations are used as a cue. PMID:24225452

  13. Experience and meaning of user involvement: some explorations from a community mental health project.

    PubMed

    Truman, Carole; Raine, Pamela

    2002-05-01

    With an increased interest in and policy commitment to involving service users in the planning and delivery of health service provision, there is a clear need to explore both the rhetoric and realities of what user involvement entails. In the present paper, by drawing upon an evaluation of a community-based exercise facility for people with mental health problems, the authors explore ways in which the reality of user involvement is subject to a range of configurations within health services. The paper describes a piece of qualitative research that was undertaken within a participatory framework to explore the nature of user involvement within the facility. The data have been analysed using a grounded theory approach to provide insights into: the organisational context in which user involvement takes place; factors which encourage meaningful participation on the part of service users; perceived barriers to user involvement; and issues of sustainability and continuity. This research approach has enabled the authors to explore the views and experiences of users, service providers and referral agencies in relation to the nature and potential for user involvement. The findings illustrate ways in which user involvement may take place under both flexible and formal arrangements across a variety of activities. The present paper provides an account of some of the meanings and experiences of what 'successful' user participation may involve and the conditions which underpin 'success'. The authors conclude that successful and meaningful user involvement should enable and support users to recognise their existing skills, and to develop new ones, at a pace that suits their particular circumstances and personal resources. This process may require adaptation not only by organisations, but also by service providers and non-involved users.

  14. Experiments on the flow and acoustic properties of a moderate-Reynolds-number supersonic jet

    NASA Technical Reports Server (NTRS)

    Troutt, T. R.; Mclaughlin, D. K.

    1982-01-01

    Flow and acoustic properties of a jet at Reynolds number of 70,000 were studied at Mach 2.1. Measurements in a free jet test facility were made with pitot tubes and hot-wire anemometry. Center-line Mach number distributions for natural and excited jets were obtained. A slow initial growth rate was in the potential core region of the jet, indicating a transition from laminar to turbulent flow in moderate Reynolds number jets. The transition occurred within the first 2-3 diameters. Spectral components were calculated for the fluctuating flowfield, and sound pressure levels were measured for the overall near-field noise. The centroid of noise was located about 8 nozzle diameters downstream. The growth rates of instabilities were determined to be in agreement with linear stability theory predictions over a broad frequency range.

  15. Binaural Simulation Experiments in the NASA Langley Structural Acoustics Loads and Transmission Facility

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Silcox, Richard (Technical Monitor)

    2001-01-01

    A location and positioning system was developed and implemented in the anechoic chamber of the Structural Acoustics Loads and Transmission (SALT) facility to accurately determine the coordinates of points in three-dimensional space. Transfer functions were measured between a shaker source at two different panel locations and the vibrational response distributed over the panel surface using a scanning laser vibrometer. The binaural simulation test matrix included test runs for several locations of the measuring microphones, various attitudes of the mannequin, two locations of the shaker excitation and three different shaker inputs including pulse, broadband random, and pseudo-random. Transfer functions, auto spectra, and coherence functions were acquired for the pseudo-random excitation. Time histories were acquired for the pulse and broadband random input to the shaker. The tests were repeated with a reflective surface installed. Binary data files were converted to universal format and archived on compact disk.

  16. Reproducible Data Processing Research for the CABRI R.I.A. experiments Acoustic Emission signal analysis

    SciTech Connect

    Pantera, Laurent

    2015-07-01

    The CABRI facility is an experimental nuclear reactor of the French Atomic Energy Commission (CEA) designed to study the behaviour of fuel rods at high burnup under Reactivity Initiated Accident (R.I.A.) conditions such as the scenario of a control rod ejection. During the experimental phase, the behaviour of the fuel element generates acoustic waves which can be detected by two microphones placed upstream and downstream from the test device. Studies carried out on the last fourteen tests showed the interest in carrying out temporal and spectral analyses on these signals by showing the existence of signatures which can be correlated with physical phenomena. We want presently to return to this rich data in order to have a new point of view by applying modern signal processing methods. Such an antecedent works resumption leads to some difficulties. Although all the raw data are accessible in the form of text files, analyses and graphics representations were not clear in reproducing from the former studies since the people who were in charge of the original work have left the laboratory and it is not easy when time passes, even with our own work, to be able to remember the steps of data manipulations and the exact setup. Thus we decided to consolidate the availability of the data and its manipulation in order to provide a robust data processing workflow to the experimentalists before doing any further investigations. To tackle this issue of strong links between data, treatments and the generation of documents, we adopted a Reproducible Research paradigm. We shall first present the tools chosen in our laboratory to implement this workflow and, then we shall describe the global perception carried out to continue the study of the Acoustic Emission signals recorded by the two microphones during the last fourteen CABRI R.I.A. tests. (authors)

  17. Education for Sustainability in University Studies: Experiences from a Project Involving European and Latin American Universities

    ERIC Educational Resources Information Center

    Geli de Ciurana, Anna M.; Filho, Walter Leal

    2006-01-01

    Purpose: To report on a project involving European and Latin American universities, focusing on curriculum greening. Design/methodology/approach: This paper presents the experiences gained in connection with the "ACES Project" which is a model of the implementation of sustainability principles in higher education, with a special emphasis…

  18. Collegiate Diversity Experiences and Students' Views Regarding Social and Political Involvement

    ERIC Educational Resources Information Center

    Parker, Eugene T., III; Trolian, Teniell L.

    2015-01-01

    Using data from the Wabash National Study of Liberal Arts Education, this study examines the relationship between engagement in diversity experiences during college and student attitudes about the importance of being socially and politically involved at the end of their fourth year of college. Findings suggest a positive link between…

  19. An e-Learning System with MR for Experiments Involving Circuit Construction to Control a Robot

    ERIC Educational Resources Information Center

    Takemura, Atsushi

    2016-01-01

    This paper proposes a novel e-Learning system for technological experiments involving electronic circuit-construction and controlling robot motion that are necessary in the field of technology. The proposed system performs automated recognition of circuit images transmitted from individual learners and automatically supplies the learner with…

  20. Moving towards Participatory Adult Education: Involving Family Literacy Students in Meaningful Leadership Experiences. Research Brief #4

    ERIC Educational Resources Information Center

    Toso, Blaire Willson; Prins, Esther; Drayton, Brendaly; Gungor, Ramazan; Gnanadass, Edith

    2008-01-01

    Although adult educators espouse values such as inclusion and ownership, adult learners seldom play a substantive role in programmatic decision making. This collaborative research project explored family literacy participants' experiences in their program's parent advisory council (PAC). The study shows that involvement in the PAC enhanced program…

  1. Parental Beliefs and Experiences Regarding Involvement in Intervention for Their Child with Speech Sound Disorder

    ERIC Educational Resources Information Center

    Watts Pappas, Nicole; McAllister, Lindy; McLeod, Sharynne

    2016-01-01

    Parental beliefs and experiences regarding involvement in speech intervention for their child with mild to moderate speech sound disorder (SSD) were explored using multiple, sequential interviews conducted during a course of treatment. Twenty-one interviews were conducted with seven parents of six children with SSD: (1) after their child's initial…

  2. Parents' Experiences as Predictors of State Accountability Measures of Schools' Facilitation of Parent Involvement

    ERIC Educational Resources Information Center

    Elbaum, Batya; Blatz, Erin T.; Rodriguez, Raymond J.

    2016-01-01

    The aim of this study was to ascertain which dimensions of parents' experiences with schools are most strongly associated with parents' perceptions that schools are or are not facilitating parent involvement as mandated by the federal accountability system under the Individuals With Disabilities Education Act (IDEA). Participants were 92 parents…

  3. Improving Community Involvement and Citizenship among Elementary School Students through Service Learning Experiences

    ERIC Educational Resources Information Center

    Smith, Mandi

    2007-01-01

    This Action Research Project was designed to increase student awareness and involvement of socio-economic differences and how the children can make a difference in their community. Service learning projects were non-existent at the Academy causing the young children to miss out on learning experiences that would teach them how to make a difference…

  4. E-Learning System for Experiments Involving Construction of Practical Electronic Circuits

    ERIC Educational Resources Information Center

    Takemura, Atsushi

    2013-01-01

    This paper proposes a novel e-learning system for technical experiments involving the construction of practical electronic circuits; this system would meet the various demands of individual experimenters. This mixed mode is beneficial for practical use in that an experimenter who does not have sufficient circuit components for circuit making can…

  5. From Corrections to Community: The Juvenile Reentry Experience as Characterized by Multiple Systems Involvement

    ERIC Educational Resources Information Center

    Cusick, Gretchen Ruth; Goerge, Robert M.; Bell, Katie Claussen

    2009-01-01

    This Chapin Hall report describes findings on the extent of system involvement among Illinois youth released from correctional facilities, tracking a population of youth under age 18 in Illinois following their release. Using administrative records, researchers develop profiles of reentry experiences across the many systems that serve youth and…

  6. Testicular microlithiasis and preliminary experience of acoustic radiation force impulse imaging

    PubMed Central

    Osther, Palle Jørn Sloth; Rafaelsen, Søren Rafael

    2016-01-01

    Background Elastography of the testis can be used as a part of multiparametric examination of the scrotum. Purpose To determine the testicular stiffness using acoustic radiation force impulse imaging (ARFI) technique in men with testicular microlithiasis (TML). Material and Methods In 2013, 12 patients with diagnosed testicular microlithiasis in 2008 (mean age, 51 years; age range, 25–76 years) underwent a 5-year follow-up B-mode ultrasonography with three ARFI elastography measurements of each testis. We used a Siemens Acuson S3000 machine. Results No malignancy was found at the 5-year follow-up B-mode and elastography in 2013. However, we found an increase in TML; in the previous ultrasonography in 2008, eight men had bilateral TML, whereas in 2013, 10 men were diagnosed with bilateral TML. The mean elasticity of testicles with TML was 0.82 m/s (interquartile range [IQR], 0.72–0.88 m/s; range, 65–1.08 m/s). Conclusion Elastography velocity of testis with TML seems to be in the same velocity range as in men with normal testis tissue. PMID:27504193

  7. Determination of acoustic nonlinearity parameter (β) using nonlinear resonance ultrasound spectroscopy: Theory and experiment.

    PubMed

    Chakrapani, Sunil Kishore; Barnard, Daniel J

    2017-02-01

    The present article investigates the possibility of using nonlinear resonance ultrasound spectroscopy to determine the acoustic nonlinearity parameter (β) and third order elastic constant by developing an inverse problem. A theoretical framework was developed for nonlinear forced vibration of a cantilever beam using material nonlinearity (stress-strain nonlinearity). The resulting nonlinear equation was solved using method of multiple time scales to obtain the nonlinear frequency shifts. The present works focuses only on classical nonlinearity and, therefore, a diverse group of intact, classic nonlinear materials were chosen. The samples were tested using nonlinear resonance ultrasound spectroscopy, and the developed theory was used to invert the experimental frequency shifts to obtain the nonlinearity parameters. The third order elastic constants and β were calculated using their analytical relationship with the nonlinearity parameter. The experimentally determined C111 and β values for all various materials agree well with literature values. In addition to determining β, determination of the sign, or phase of β was also explored theoretically and experimentally.

  8. Importance of spontaneous alpha-ketoacid decarboxylation in experiments involving peroxide.

    PubMed

    Vlessis, A A; Bartos, D; Trunkey, D

    1990-08-16

    The potential role of spontaneous alpha-ketoacid decarboxylation as a source of interference in experiments involving peroxide was investigated. The assay of pyruvate dehydrogenase activity in isolated renal mitochondria was employed as an example. Spontaneous peroxide-induced pyruvate decarboxylation competed significantly with enzymatic decarboxylation at peroxide concentrations greater than 50 microM. Corrected values for enzymatic decarboxylation could be obtained by subtracting spontaneous decarboxylation rates from rates obtained in the presence of mitochondria. At higher peroxide concentrations (greater than 200 microM), reaction product accumulates (acetoacetate) to levels which may have regulatory effects on mitochondrial metabolism. The divalent cations, Ca2+ and Mg2+, both accelerate spontaneous peroxide-induced pyruvate decarboxylation while other components of the assay medium had an inhibitory effect on the reaction. The results are discussed in relation to the currently accepted reaction mechanism. Investigators who perform experiments involving reactive oxygen species should be familiar with this often overlooked reaction.

  9. Right hemisphere involvement in depression: toward a neuropsychological theory of negative affective experiences.

    PubMed

    Otto, M W; Yeo, R A; Dougher, M J

    1987-10-01

    Several lines of inquiry provide converging evidence for a critical role for the right cerebral hemisphere in negative affective experiences. This research includes the assessment of affective consequences of both focal cerebral lesions and pharmacological inactivation of one or the other hemisphere, as well as experimental and physiological techniques assessing differential hemispheric activation. The specific nature of right hemispheric involvement is conceptualized as a tendency to become activated by aversive experiences, and once activated, to process stimuli in a manner consistent with the right hemisphere's more negative affective tone. A theory of right hemisphere involvement in depressive affect is presented in detail and its relevance to clinical phenomena, e.g., the co-occurrence of depression and pain, and sex differences in depression, is examined, as is congruence with cognitive theories of depression.

  10. A direct method for measuring acoustic ground impedance in long-range propagation experiments.

    PubMed

    Soh, Jin H; Gilbert, Kenneth E; Frazier, W M Garth; Talmadge, Carrick L; Waxler, Roger

    2010-11-01

    A method is reported for determining ground impedance in long-range propagation experiments by using the definition of impedance directly. The method is envisioned as way of measuring the impedence at multiple locations along the propagation path, using the signals broadcast during the experiment itself. In a short-range (10 m) test, the direct method was in good agreement with a more conventional model-based least-squares method. The utility of the direct method was demonstrated in a 400 m propagation experiment in a agricultural field. The resulting impedance was consistent with the impedance measured previously in the same field.

  11. Co‐researching with people with learning disabilities: an experience of involvement in qualitative data analysis

    PubMed Central

    Tuffrey‐Wijne, Irene; Butler, Gary

    2009-01-01

    Abstract Background  People with learning disabilities have been included in research as co‐researchers since the 1990s. However, there is limited literature about the processes of involving people with learning disabilities in the more intellectual and analytical stages of the research process. Aims  To examine the potential contribution of people with learning disabilities to data analysis in qualitative research. Methods  This article is a reflection on one research experience. The two authors include one researcher with and one without learning disabilities. They each describe their experience and understanding of user involvement in analysing the data of an ethnographic study of people with learning disabilities who had cancer. The researcher with learning disabilities was given extensive vignettes and extracts from the research field notes, and was supported to extract themes, which were cross‐compared with the analysis of other members of the research team. Results  The researcher with learning disabilities coped well with the emotive content of the data and with the additional support provided, he was able to extract themes that added validity to the overall analysis. His contribution complemented those of the other members of the research team. There were unexpected benefits, in particular, in terms of a more reciprocal and supportive relationship between the two researchers. Conclusion  It is possible and valuable to extend involvement to data analysis, but to avoid tokenism and maintain academic rigour, there must be a clear rationale for such involvement. Extra support, time and costs must be planned for. PMID:19737315

  12. 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 ...

  13. Feasibility of reduced gravity experiments involving quiescent, uniform particle cloud combustion

    NASA Technical Reports Server (NTRS)

    Ross, Howard D.; Facca, Lily T.; Berlad, Abraham L.; Tangirala, Venkat

    1989-01-01

    The study of combustible particle clouds is of fundamental scientific interest as well as a practical concern. The principal scientific interests are the characteristic combustion properties, especially flame structure, propagation rates, stability limits, and the effects of stoichiometry, particle type, transport phenomena, and nonadiabatic processes on these properties. The feasibility tests for the particle cloud combustion experiment (PCCE) were performed in reduced gravity in the following stages: (1) fuel particles were mixed into cloud form inside a flammability tube; (2) when the concentration of particles in the cloud was sufficiently uniform, the particle motion was allowed to decay toward quiescence; (3) an igniter was energized which both opened one end of the tube and ignited the suspended particle cloud; and (4) the flame proceeded down the tube length, with its position and characteristic features being photographed by high-speed cameras. Gravitational settling and buoyancy effects were minimized because of the reduced gravity enviroment in the NASA Lewis drop towers and aircraft. Feasibility was shown as quasi-steady flame propagation which was observed for fuel-rich mixtures. Of greatest scientific interest is the finding that for near-stoichiometric mixtures, a new mode of flame propagation was observed, now called a chattering flame. These flames did not propagate steadily through the tube. Chattering modes of flame propagation are not expected to display extinction limits that are the same as those for acoustically undisturbed, uniform, quiescent clouds. A low concentration of fuel particles, uniformly distributed in a volume, may not be flammable but may be made flammable, as was observed, through induced segregation processes. A theory was developed which showed that chattering flame propagation was controlled by radiation from combustion products which heated the successive discrete laminae sufficiently to cause autoignition.

  14. Classical Experiments Revisited: Smartphones and Tablet PCs as Experimental Tools in Acoustics and Optics

    ERIC Educational Resources Information Center

    Klein, P.; Hirth, M.; Gröber, S.; Kuhn, J.; Müller, A.

    2014-01-01

    Smartphones and tablets are used as experimental tools and for quantitative measurements in two traditional laboratory experiments for undergraduate physics courses. The Doppler effect is analyzed and the speed of sound is determined with an accuracy of about 5% using ultrasonic frequency and two smartphones, which serve as rotating sound emitter…

  15. A note on acoustic measurements of turbulence, suspended sediment, and bed forms in mobile bed experiments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the challenges of hydraulic experimentation is designing experiments that are complex enough to capture relevant processes while retaining the simplicity necessary for useful, accurate measurements. The intricacy of the interactions between turbulent flows and mobile beds in rivers and stream...

  16. Acoustic and Oceanographic Observations and Configuration Information for the WHOI Moorings from the SW06 Experiment

    DTIC Science & Technology

    2007-05-01

    application ............................................................................................................... 43 6.0 Shark HLA VVLA...Oceanographic Observations and Configuration Information for the WHOI moorings from the SW06 Experiment 2 6.1 Shark m ooring configuration...46 6.2 Shark 48 Channel HLA/VLA data acquisition system and data

  17. Deep Water Ocean Acoustics (DWOA): The Philippine Sea, OBSANP, and THAAW Experiments

    DTIC Science & Technology

    2015-09-30

    enabling advanced signal processing techniques to capitalize on the three-dimensional character of the sound and noise fields. OBJECTIVES...scattering by internal waves and spice (density- compensated temperature and salinity variations), (iv) characterizing the depth dependence and temporal...relationship between deep ocean ambient noise and sea surface processes that generate sound (Stephen et al., 2014). The experiment was motivated in part

  18. Acoustic Remote Sensing

    NASA Astrophysics Data System (ADS)

    Dowling, David R.; Sabra, Karim G.

    2015-01-01

    Acoustic waves carry information about their source and collect information about their environment as they propagate. This article reviews how these information-carrying and -collecting features of acoustic waves that travel through fluids can be exploited for remote sensing. In nearly all cases, modern acoustic remote sensing involves array-recorded sounds and array signal processing to recover multidimensional results. The application realm for acoustic remote sensing spans an impressive range of signal frequencies (10-2 to 107 Hz) and distances (10-2 to 107 m) and involves biomedical ultrasound imaging, nondestructive evaluation, oil and gas exploration, military systems, and Nuclear Test Ban Treaty monitoring. In the past two decades, approaches have been developed to robustly localize remote sources; remove noise and multipath distortion from recorded signals; and determine the acoustic characteristics of the environment through which the sound waves have traveled, even when the recorded sounds originate from uncooperative sources or are merely ambient noise.

  19. Packages of participation: Swedish employees’ experience of Lean depends on how they are involved

    PubMed Central

    Brännmark, Mikael; Holden, Richard J.

    2013-01-01

    Background Lean Production is a dominant approach in Swedish and global manufacturing and service industries. Studies of Lean’s employee effects are few and contradictory. Purpose Employee effects from Lean are likely not uniform. This paper investigates the effect of employees' participation on their experiences of Lean. Method This study investigated how different packages of employee participation in Lean affected manufacturing workers’ experiences of Lean. During 2008–2011, qualitative and quantitative data were collected from Swedish manufacturing companies participating in the national Swedish Lean Production program Produktionslyftet. Data from 129 surveys (28 companies), 39 semi-structured interviews, and 30 reports were analyzed. In the main analysis, comparisons were made of the survey-reported Lean experiences of employees in three groups: temporary group employees (N = 36), who participated in Lean mostly through intermittent projects; continuous group employees (N = 69), who participated through standing improvement groups; and combined group employees (N = 24), who participated in both ways. Results Continuous group employees had the most positive experience of Lean, followed by the combined group. Temporary group employees had the least positive experiences, being less likely than their counterparts to report that Lean improved teamwork, occupational safety, and change-related learning, decision making, and authority. Conclusions These findings support the importance of continuous, structured opportunities for participation but raise the possibility that more participation may result in greater workload and role overload, mitigating some benefits of employee involvement. Consequently, companies should consider involving employees in change efforts but should attend to the specific design of participation activities. PMID:24665370

  20. Classical experiments revisited: smartphones and tablet PCs as experimental tools in acoustics and optics

    NASA Astrophysics Data System (ADS)

    Klein, P.; Hirth, M.; Gröber, S.; Kuhn, J.; Müller, A.

    2014-07-01

    Smartphones and tablets are used as experimental tools and for quantitative measurements in two traditional laboratory experiments for undergraduate physics courses. The Doppler effect is analyzed and the speed of sound is determined with an accuracy of about 5% using ultrasonic frequency and two smartphones, which serve as rotating sound emitter and stationary sound detector. Emphasis is put on the investigation of measurement errors in order to judge experimentally derived results and to sensitize undergraduate students to the methods of error estimates. The distance dependence of the illuminance of a light bulb is investigated using an ambient light sensor of a mobile device. Satisfactory results indicate that the spectrum of possible smartphone experiments goes well beyond those already published for mechanics.

  1. Hypothesis: the sound of the individual metabolic phenotype? Acoustic detection of NMR experiments.

    PubMed

    Cacciatore, Stefano; Saccenti, Edoardo; Piccioli, Mario

    2015-03-01

    We present here an innovative hypothesis and report preliminary evidence that the sound of NMR signals could provide an alternative to the current representation of the individual metabolic fingerprint and supply equally significant information. The NMR spectra of the urine samples provided by four healthy donors were converted into audio signals that were analyzed in two audio experiments by listeners with both musical and non-musical training. The listeners were first asked to cluster the audio signals of two donors on the basis of perceived similarity and then to classify unknown samples after having listened to a set of reference signals. In the clustering experiment, the probability of obtaining the same results by pure chance was 7.04% and 0.05% for non-musicians and musicians, respectively. In the classification experiment, musicians scored 84% accuracy which compared favorably with the 100% accuracy attained by sophisticated pattern recognition methods. The results were further validated and confirmed by analyzing the NMR metabolic profiles belonging to two other different donors. These findings support our hypothesis that the uniqueness of the metabolic phenotype is preserved even when reproduced as audio signal and warrants further consideration and testing in larger study samples.

  2. Amyloidosis involving the respiratory system: 5-year's experience of a multi-disciplinary group's activity.

    PubMed

    Scala, Raffaele; Maccari, Uberto; Madioni, Chiara; Venezia, Duccio; La Magra, Lidia Calogera

    2015-01-01

    Amyloidosis may involve the respiratory system with different clinical-radiological-functional patterns which are not always easy to be recognized. A good level of knowledge of the disease, an active integration of the pulmonologist within a multidisciplinary setting and a high level of clinical suspicion are necessary for an early diagnosis of respiratory amyloidosis. The aim of this retrospective study was to evaluate the number and the patterns of amyloidosis involving the respiratory system. We searched the cases of amyloidosis among patients attending the multidisciplinary rare and diffuse lung disease outpatients' clinic of Pulmonology Unit of the Hospital of Arezzo from 2007 to 2012. Among the 298 patients evaluated during the study period, we identified three cases of amyloidosis with involvement of the respiratory system, associated or not with other extra-thoracic localizations, whose diagnosis was histo-pathologically confirmed after the pulmonologist, the radiologist, and the pathologist evaluation. Our experience of a multidisciplinary team confirms that intra-thoracic amyloidosis is an uncommon disorder, representing 1.0% of the cases of rare and diffuse lung diseases referred to our center. The diagnosis of the disease is not always easy and quick as the amyloidosis may involve different parts of the respiratory system (airways, pleura, parenchyma). It is therefore recommended to remind this orphan disease in the differential diagnosis of the wide clinical scenarios the pulmonologist may intercept in clinical practice.

  3. Offshore exposure experiments on cuttlefish indicate received sound pressure and particle motion levels associated with acoustic trauma

    PubMed Central

    Solé, Marta; Sigray, Peter; Lenoir, Marc; van der Schaar, Mike; Lalander, Emilia; André, Michel

    2017-01-01

    Recent findings on cephalopods in laboratory conditions showed that exposure to artificial noise had a direct consequence on the statocyst, sensory organs, which are responsible for their equilibrium and movements in the water column. The question remained about the contribution of the consequent near-field particle motion influence from the tank walls, to the triggering of the trauma. Offshore noise controlled exposure experiments (CEE) on common cuttlefish (Sepia officinalis), were conducted at three different depths and distances from the source and particle motion and sound pressure measurements were performed at each location. Scanning electron microscopy (SEM) revealed injuries in statocysts, which severity was quantified and found to be proportional to the distance to the transducer. These findings are the first evidence of cephalopods sensitivity to anthropogenic noise sources in their natural habitat. From the measured received power spectrum of the sweep, it was possible to determine that the animals were exposed at levels ranging from 139 to 142 dB re 1 μPa2 and from 139 to 141 dB re 1 μPa2, at 1/3 octave bands centred at 315 Hz and 400 Hz, respectively. These results could therefore be considered a coherent threshold estimation of noise levels that can trigger acoustic trauma in cephalopods. PMID:28378762

  4. Offshore exposure experiments on cuttlefish indicate received sound pressure and particle motion levels associated with acoustic trauma.

    PubMed

    Solé, Marta; Sigray, Peter; Lenoir, Marc; van der Schaar, Mike; Lalander, Emilia; André, Michel

    2017-04-05

    Recent findings on cephalopods in laboratory conditions showed that exposure to artificial noise had a direct consequence on the statocyst, sensory organs, which are responsible for their equilibrium and movements in the water column. The question remained about the contribution of the consequent near-field particle motion influence from the tank walls, to the triggering of the trauma. Offshore noise controlled exposure experiments (CEE) on common cuttlefish (Sepia officinalis), were conducted at three different depths and distances from the source and particle motion and sound pressure measurements were performed at each location. Scanning electron microscopy (SEM) revealed injuries in statocysts, which severity was quantified and found to be proportional to the distance to the transducer. These findings are the first evidence of cephalopods sensitivity to anthropogenic noise sources in their natural habitat. From the measured received power spectrum of the sweep, it was possible to determine that the animals were exposed at levels ranging from 139 to 142 dB re 1 μPa(2) and from 139 to 141 dB re 1 μPa(2), at 1/3 octave bands centred at 315 Hz and 400 Hz, respectively. These results could therefore be considered a coherent threshold estimation of noise levels that can trigger acoustic trauma in cephalopods.

  5. Measuring spirituality as a universal human experience: development of the Spiritual Attitude and Involvement List (SAIL).

    PubMed

    de Jager Meezenbroek, Eltica; Garssen, Bert; Van den Berg, Machteld; Tuytel, Gerwi; Van Dierendonck, Dirk; Visser, Adriaan; Schaufeli, Wilmar B

    2012-01-01

    Many cancer patients experience spirituality as highly supportive while coping with their disease. Most research as well as most questionnaires in this field is religious orientated. The Spiritual Attitude and Involvement List was developed to enable research on spirituality among religious and nonreligious people. It consists of seven subscales that measure connectedness with oneself, with others and nature, and with the transcendent. Among a student, a healthy population, a healthy interested, a curative cancer, and a palliative cancer sample factorial, convergent and discriminant validity were demonstrated, as well as adequate internal consistency and test-retest reliability.

  6. Experiments Involving Pool and Vapor Fires from Spills of Liquefied Natural Gas on Water

    DTIC Science & Technology

    1979-06-01

    technical representative for the work perfor ein was Dr. M. C. PARNAROUSKIS/ A series of 16 tests have ws1’conducted at the Naval Weapons Center involving...Specific Spectral Scan 4- 16 4.5.2 Changes in Spectral Data vith Burn Time 4-20 4.5.3 Estimation of Soot Temperature and Emissivity 4-22 4.5.4 Estimation...Fire Data 5- 16 5.3.1 Qualitative Observation@ on Pool Fire 5- 16 Behavior 5.3.2 Quantitative Data from Pool Fire Experiments 5-!• 5.3.3 Correlation of the

  7. A phenomenographic analysis of first-year engineering students' experiences with problems involving multiple possible solutions

    NASA Astrophysics Data System (ADS)

    Dringenberg, Emily A.

    Engineers are expected to solve problems that are ill-structured. These problems are presented with a lack of necessary information and allow for different ways of engaging with the problem; they are open-ended and involve multiple possible solutions with multiple means of evaluation. In order to allow maximum time for students to develop skills for solving such problems, undergraduate engineering programs can introduce such problems during the first year of students' education, in the form of cornerstone design tasks. This provides students with more opportunities to develop their ability to engage with ill-structured problems, which are characteristic of engineering work. Researchers have documented variation within both the behavior and perceptions of students' early experiences with design problems. General themes include novice-like design behavior, discomfort with lack of information, difficulty with problem scoping, and resistance to ambiguity. To build on these generalizations of students' experiences, a more thorough understanding of the variation in how students experience this phenomenon of engaging with ill-structured problems is needed to design effective learning environments. This work presents the qualitatively different ways that engineering students experience problems with multiple possible solutions during their first year of engineering studies. Using phenomenography as the methodological framework, data were collected through in-depth, semi-structured interviews with 27 first-year engineering students. The iterative, phenomenographic analysis resulted in seven descriptive categories for the ways participants experienced problems involving multiple possible solutions. The names of these categories represent the different foci of the students' experiences: completion, transition, iteration, organization, collaboration, reasoning, and growth. These categories are organized along two crucial dimensions of variation: reaction to ambiguity and role

  8. [Reactions of caudate nucleus neurons to presentation of acoustic clicks to cats in a chronic experiment].

    PubMed

    Litvinova, A N; Lukhanina, E P

    1980-01-01

    Background and evoked activities of the caudate nucleus neurons to repetitive auditory clicks were recorded extracellularly in chronic experiments with partial restrained cats. Four types of background neuronal activity were distinguished. 44% of recorded units altered their background activity during auditory click applications. Five types of neuronal responses were found: phasic activation, phasic inhibition, tonic activation, tonic inhibition, mixed tonic reactions. Tonic activation was predominant. The phasic responses persisted under prolonged presentation of clicks. Partial or total attenuation of tonic responses during frequent repetition of clicks occurred in 33% of responding units. The question is discussed on the convergence of specific and unspecific influences on the caudate nucleus neurons.

  9. Sexual risk, substance use, mental health, and trauma experiences of gang-involved homeless youth.

    PubMed

    Petering, Robin

    2016-04-01

    This study examined the associations of sexual risk behaviors, substance use, mental health, and trauma with varying levels of gang involvement in a sample of Los Angeles-based homeless youths. Data were collected from 505 homeless youths who self-reported various health information and whether they have ever identified as or been closely affiliated with a gang member. Multivariable logistic regression assessed associations of lifetime gang involvement with risk taking behaviors and negative health outcomes. Results revealed seventeen percent of youths have ever identified as a gang member and 46% as gang affiliated. Both gang members and affiliates were at greater risk of many negative behaviors than non-gang involved youths. Gang members and affiliates were more likely to report recent methamphetamine use, cocaine use, chronic marijuana use, having sex while intoxicated, and symptoms of depression, symptoms of posttraumatic stress disorder. They were also more likely to have experienced childhood sexual abuse and witnessing family violence. Gang members were more likely to ever attempt suicide, experience recent partner violence, and report physical abuse during childhood. Results suggest that lifetime gang involvement is related to a trajectory of negative outcomes and amplified risk for youths experiencing homelessness. Additionally, being closely connected to a gang member appears to have just as much as an impact on risk as personally identifying as a gang member. Given the lack of knowledge regarding the intersection between youth homelessness and gang involvement, future research is needed to inform policies and programs that can address the specific needs of this population.

  10. 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.

  11. 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.

  12. Acoustic measurements from a rotor blade-vortex interaction noise experiment in the German-Dutch Wind Tunnel (DNW)

    NASA Technical Reports Server (NTRS)

    Martin, Ruth M.; Splettstoesser, W. R.; Elliott, J. W.; Schultz, K.-J.

    1988-01-01

    Acoustic data are presented from a 40 percent scale model of the 4-bladed BO-105 helicopter main rotor, measured in the large European aeroacoustic wind tunnel, the DNW. Rotor blade-vortex interaction (BVI) noise data in the low speed flight range were acquired using a traversing in-flow microphone array. The experimental apparatus, testing procedures, calibration results, and experimental objectives are fully described. A large representative set of averaged acoustic signals is presented.

  13. Generation of Acoustic-Gravity Waves in Ionospheric HF Heating Experiments: Simulating Large-Scale Natural Heat Sources

    NASA Astrophysics Data System (ADS)

    Pradipta, Rezy

    In this thesis, we investigate the potential role played by large-scale anomalous heat sources (e.g. prolonged heat wave events) in generating acoustic-gravity waves (AGWs) that might trigger widespread plasma turbulence in the ionospheric layer. The main hypothesis is that, the thermal gradients associated with the heat wave fronts could act as a source of powerful AGW capable of triggering ionospheric plasma turbulence over extensive areas. In our investigations, first we are going to examine a case study of the summer 2006 North American heat wave event. Our examination of GPS-derived total electron content (TEC) data over the North American sector reveals a quite noticeable increase in the level of daily plasma density fluctuations during the summer 2006 heat wave period. Comparison with the summer 2005 and summer 2007 data further confirms that the observed increase of traveling ionospheric disturbances (TIDs) during the summer 2006 heat wave period was not simply a regular seasonal phenomenon. Furthermore, a series of field experiments had been carried out at the High-frequency Active Auroral Research Program (HAARP) facility in order to physically simulate the process of AGW/TID generation by large-scale thermal gradients in the ionosphere. In these ionospheric HF heating experiments, we create some time-varying artificial thermal gradients at an altitude of 200--300 km above the Earth's surface using vertically-transmitted amplitude-modulated 0-mode HF heater waves. For our experiments, a number of radio diagnostic instruments had been utilized to detect the characteristic signatures of heater-generated AGW/TID. So far, we have been able to obtain several affirmative indications that some artificial AGW/TID are indeed being radiated out from the heated plasma volume during the HAARP-AGW experiments. Based on the experimental evidence, we may conclude that it is certainly quite plausible for large-scale thermal gradients associated with severe heat wave

  14. Evaluation of a scale-model experiment to investigate long-range acoustic propagation

    NASA Technical Reports Server (NTRS)

    Parrott, Tony L.; Mcaninch, Gerry L.; Carlberg, Ingrid A.

    1987-01-01

    Tests were conducted to evaluate the feasibility of using a scale-model experiment situated in an anechoic facility to investigate long-range sound propagation over ground terrain. For a nominal scale factor of 100:1, attenuations along a linear array of six microphones colinear with a continuous-wave type of sound source were measured over a wavelength range from 10 to 160 for a nominal test frequency of 10 kHz. Most tests were made for a hard model surface (plywood), but limited tests were also made for a soft model surface (plywood with felt). For grazing-incidence propagation over the hard surface, measured and predicted attenuation trends were consistent for microphone locations out to between 40 and 80 wavelengths. Beyond 80 wavelengths, significant variability was observed that was caused by disturbances in the propagation medium. Also, there was evidence of extraneous propagation-path contributions to data irregularities at more remote microphones. Sensitivity studies for the hard-surface and microphone indicated a 2.5 dB change in the relative excess attenuation for a systematic error in source and microphone elevations on the order of 1 mm. For the soft-surface model, no comparable sensitivity was found.

  15. Acoustic emission monitoring of hydraulic fracturing laboratory experiment with supercritical and liquid CO2

    NASA Astrophysics Data System (ADS)

    Ishida, Tsuyoshi; Aoyagi, Kazuhei; Niwa, Tomoya; Chen, Youqing; Murata, Sumihiko; Chen, Qu; Nakayama, Yoshiki

    2012-08-01

    Carbon dioxide (CO2) is often used for enhanced oil recovery in depleted petroleum reservoirs, and its behavior in rock is also of interest in CO2 capture and storage projects. CO2 usually becomes supercritical (SC-CO2) at depths greater than 1,000 m, while it is liquid (L-CO2) at low temperatures. The viscosity of L-CO2 is one order lower than that of normal liquid water, and that of SC-CO2 is much lower still. To clarify fracture behavior induced with injection of the low viscosity fluids, we conducted hydraulic fracturing experiments using 17 cm cubic granite blocks. The AE sources with the SC- and L-CO2 injections tend to distribute in a larger area than those with water injection, and furthermore, SC-CO2 tended to generate cracks extending more three dimensionally rather than along a flat plane than L-CO2. It was also found that the breakdown pressures for SC- and L-CO2 injections are expected to be considerably lower than for water.

  16. Modeling the Infrasound Acoustic Signal Generation of Underground Explosions at the Source Physics Experiment

    NASA Astrophysics Data System (ADS)

    Whitaker, R. W.; Jones, K. R.; Arrowsmith, S.

    2013-12-01

    One of the primary goals of the Source Physics Experiment is to improve upon and develop new physics based models for underground nuclear explosions using scaled, underground chemical explosions as proxies. Jones et. al, (AGU 2012) previously presented results describing the use of the Rayleigh integral (RI) to model the source region of the SPE explosions. While these results showed that the source region could be modeled using the RI, there were some complexities in the produced, synthetic waveforms that were unaccounted for when compared to the observed data. To gain insight into these complexities and to verify the results of the RI method, we used CAVEAT, a two-dimensional computational fluid dynamics, time-domain finite-difference code developed at Los Alamos National Labs (LANL). CAVEAT has been used in the solution of high speed and low speed fluid problems. While the RI uses the observed acceleration records from the 12 vertical surface accelerometers installed above ground zero, CAVEAT employs a synthetic source-time function, based on the acceleration records, that varies with range and time. This model provides a velocity boundary condition at the bottom boundary of the CAVEAT computation mesh that drives the atmospheric pressure wave into the atmosphere.

  17. Community involvement among behaviourally bisexual men in the Midwestern USA: experiences and perceptions across communities.

    PubMed

    Dodge, Brian; Schnarrs, Phillip W; Reece, Michael; Goncalves, Gabriel; Martinez, Omar; Nix, Ryan; Malebranche, David; Van Der Pol, Barbara; Murray, Maresa; Fortenberry, J Dennis

    2012-10-01

    Limited research exists regarding community involvement and social support among behaviourally bisexual men. Previous studies suggest that bisexual men experience high levels of social stigma in both heterosexual and homosexual community settings. Research focusing on social support has demonstrated that individuals with limited access to similar individuals experience greater risk for negative health outcomes. Using a community-based research design, participants were recruited using multiple methods. Researchers conducted in-depth, semi-structured interviews with 75 men who reported having engaged in bisexual behaviour within the past six months. Interviews elucidated the experiences of behaviourally bisexual men in heterosexual and homosexual settings, as well as their perceptions of the existence of a bisexual community or bisexual spaces. All participants perceived a lack of a visible bisexual community and expressed difficulty with being comfortable, or a feeling of belonging, within a variety of heterosexual and homosexual community spaces. Findings suggest the need for interventions focused on community building among, as well as creating spaces specifically designed for, bisexual men in order to increase perceived social support and decrease isolation and possible negative health outcomes.

  18. Community Involvement among Behaviourally Bisexual Men in the Midwestern USA: Experiences and Perceptions across Communities

    PubMed Central

    Dodge, Brian; Schnarrs, Phillip W.; Reece, Michael; Goncalves, Gabriel; Martinez, Omar; Nix, Ryan; Malebranche, David; Van Der Pol, Barbara; Murray, Maresa; Fortenberry, J. Dennis

    2012-01-01

    Limited research exists regarding community involvement and social support among behaviourally bisexual men. Previous studies suggest that bisexual men experience high levels of social stigma in both heterosexual and homosexual community settings. Research focusing on social support has demonstrated that individuals with limited access to similar individuals experience greater risk for negative health outcomes. Using a community-based research design, participants were recruited using multiple methods in Indianapolis, Indiana, USA. Researchers conducted in-depth, semi-structured interviews with 75 men who reported having engaged in bisexual behaviour within the past six months. Interviews elucidated the experiences of behaviourally bisexual men in heterosexual and homosexual settings, as well as their perceptions of the existence of a bisexual community or bisexual spaces. All participants perceived a lack of a visible bisexual community and expressed difficulty with being comfortable, or feeling belonging, within a variety of heterosexual and homosexual community spaces. Findings suggest the need for interventions focused on community building among, as well as creating spaces specifically designed for, bisexual men in order to increase perceived social support and decrease isolation and possible negative health outcomes. PMID:22978551

  19. Evaluation of Wave Propagation Properties during a True-Triaxial Rock Fracture Experiment using Acoustic Emission Frequency Characteristics

    NASA Astrophysics Data System (ADS)

    Goodfellow, S. D.; Ghofrani Tabari, M.; Nasseri, M. B.; Young, R.

    2013-12-01

    A true-triaxial deformation experiment was conducted to study the evolution of wave propagation properties by using frequency characteristics of AE waveforms to diagnose the state of fracturing in a sample of sandstone. Changes in waveform frequency content has been interpreted as either the generation of progressively larger fractures or the relative attenuation of high-frequency wave components as a result of micro-crack formation. A cubic sample of Fontainebleau sandstone was initially loaded to a stress state of σ1 = σ2 = 35 MPa, σ3 = 5 MPa at which point σ1¬ was increased until failure. Acoustic emission (AE) activity was monitored by 18 PZT transducers, three embedded in each platen. The sensor amplitude response spectrum was determined by following an absolute source calibration procedure and showed a relatively constant sensitivity in the frequency range between 20 kHz and 1200 kHz. Amplified waveforms were continuously recorded at a sampling rate of 10 MHz and 12-bit resolution. Continuous acoustic emission waveforms were harvested to extract discrete events. Using a time-varying transverse isotropic velocity model, 48,502 events were locatable inside the sample volume. Prior to peak-stress, AE activity was associated with stable quasi-static growth of fractures coplanar with σ1 and σ2 located near the platen boundaries. In the post peak-stress regime, fracture growth displays unstable ¬dynamic propagation. Analysis of waveform frequency characteristics was limited to the pre peak-stress regime. Analysis of AE frequency characteristics was conducted on all 48,502 located AE events; each event file containing 18 waveforms of varied quality. If the signal to noise ratio was greater than 5, the waveforms power spectrum was estimated and the source-receiver raypath vector was calculated. The power spectrum of each waveform was divided into three frequency bands (Low: 100 - 300 kHz, Medium: 300 - 600 kHz and High: 600 - 1000 kHz) and the power in each

  20. Promoting healthy, meaningful aging through social involvement: building an experience corps.

    PubMed

    Carlson, Michelle C

    2011-05-01

    Pathways responsible for higher-order thinking in the prefrontal cortex (PFC), or executive center of the brain, remain vulnerable throughout life-during critical early-life developmental windows, when the PFC fully matures in the early 20s, and finally from declines associated with old age. At all ages, physical activity and PFC-navigated social connections are essential components to maintaining brain health. The Experience Corps, a community-based social-engagement program, partners seniors with local schools to promote purpose-driven involvement. Participating seniors have exhibited immediate short-term gains in brain regions vulnerable to aging, such as the PFC, indicating that people with the most to lose have the most to gain from environmental enrichment.

  1. Varieties of Musical Experience

    ERIC Educational Resources Information Center

    Bharucha, J. Jamshed; Curtis, Meagan; Paroo, Kaivon

    2006-01-01

    In this paper, we argue that music cognition involves the use of acoustic and auditory codes to evoke a variety of conscious experiences. The variety of domains that are encompassed by music is so diverse that it is unclear whether a single domain of structure or experience is defining. Music is best understood as a form of communication in which…

  2. A longitudinal online interprofessional education experience involving family nurse practitioner students and pharmacy students.

    PubMed

    Collins, Andrea; Broeseker, Amy; Cunningham, Jill; Cortes, Cyndi; Beall, Jennifer; Bigham, Amy; Chang, Jongwha

    2017-03-01

    Interprofessional education (IPE) continues to gain traction worldwide. Challenges integrating IPE into health profession programmes include finding convenient times, meeting spaces, and level-appropriate assignments for each profession. This article describes the implementation of a 21-month prospective cohort study pilot programme for the Master of Science in nursing family nurse practitioner (FNP) and doctor of pharmacy (PharmD) students at a private university in the United States. This IPE experience utilised a blended approach for the learning activities; these students had initial and final sessions where they met face-to-face, with asynchronous online activities between these two sessions. The online assignments, discussions, and quizzes during the pilot programme involved topics such as antimicrobial stewardship, hormone replacement therapy, human papilloma virus vaccination, prenatal counselling, emergency contraception, and effects of the Affordable Care Act on practice. The results suggested that the FNP students held more favourable attitudes about online IPE and that the PharmD students reported having a clearer understanding of their own roles and those of the other participating healthcare students. However, the students also reported wanting more face-to-face interaction during their online IPE experience. Implications from this study suggest that effective online IPE can be supported by ensuring educational parity between students regarding the various topics discussed and a consistent approach of the required involvement for all student groups is needed. In addition, given the students desire for more face-to-face interaction, it may be beneficial to offer online IPE activities for a shorter time period. It is anticipated that this study may inform other programmes that are exploring innovative approaches to provide IPE to promote effective collaboration in patient care.

  3. Sharing experiences of user involvement in shaping new services: the story of a national patient group.

    PubMed

    Donaldson, Alison; Lank, Elizabeth; Maher, Jane

    2007-01-01

    When the Cancer Genetics Pilots Programme was established in 2004, Macmillan Cancer Support undertook to create and facilitate the work of a "National User Reference Group". The purpose of this group was to give service user representatives (patients and carers) from each of the seven pilot projects regular opportunities to meet and share experiences and thus strengthen the influence of patients on the services. Macmillan commissioned a narrative writer to record key aspects of the national user group's work and influence. The emerging narrative accounts, created in collaboration with its members, provide a picture of a diverse group of skilled and enterprising individuals, enthusiastic about helping future patients. Service users have contributed to shaping projects, improving written information and sustaining the local services. In addition, project staff responsible for user involvement highlighted the value of training for user representatives and the need to remove financial and logistical barriers to participation. The national user group itself received vital support from Macmillan in the form of a dedicated "group facilitator", as well as continuous guidance and encouragement from a senior manager (an "organisational sponsor") present at all the group's meetings. By the end of 2006, the group discussions indicated that user involvement had developed to varying degrees and in different forms across the pilot projects. In the best case, patient representatives were being "treated as part of the team".

  4. 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.

  5. Analysis of existing data from a Distributed Acoustic Sensing experiment at Garner Valley, California using noise correlation functions (PoroTomo Substask 3.2)

    DOE Data Explorer

    Zeng, Xiangfang

    2015-03-26

    In September 2013, an experiment using Distributed Acoustic Sensing (DAS) was conducted at Garner Valley, a test site of the University of California Santa Barbara (Lancelle et al., 2014). This submission includes noise cross-correlation functions (NCF) . Each file includes a NCF between two channels. The name of each channel denotes the distance in meters from starting point of the fiber-optic cable. Lancelle, C., N. Lord, H. Wang, D. Fratta, R. Nigbor, A. Chalari, R. Karaulanov, J. Baldwin, and E. Castongia (2014), Directivity and Sensitivity of Fiber-Optic Cable Measuring Ground Motion using a Distributed Acoustic Sensing Array (abstract # NS31C-3935), AGU Fall Meeting. https://agu.confex.com/agu/fm14/meetingapp.cgi#Paper/19828 The e-poster is available at: https://agu.confex.com/data/handout/agu/fm14/Paper_19828_handout_696_0.pdf

  6. 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 ...

  7. The experience of mental distress and recovery among people involved with the service user/survivor movement.

    PubMed

    Chassot, Carolina S; Mendes, Felismina

    2015-07-01

    This article examines how the personal experiences of mental distress of people involved in the British service user/survivor movement were shaped or transformed by this involvement, and the impact of involvement on their recovery journeys. The analysis was based on 12 in-depth interviews with service users/survivors who are, or were once, involved with the service user/survivor movement. Three large themes were identified regarding the ways in which social movement involvement affected the personal experience of mental distress: (a) making sense and reframing mental distress, (b) the social experience of involvement and (c) identity and identity reconstruction. We discuss how some features of the service user/survivor movement, such as self-help, user involvement, the centrality of experience to collective action, and the range of political positions adopted by activists can affect experience and recovery in different forms. As an exploratory study that looks into a complex topic, our findings illuminate the ways of surviving, recovering and experiencing mental distress in the context of a significant social movement.

  8. The Role of Student Support Services in Encouraging Student Involvement and Its Impact on Student Perceptions and Academic Experiences

    ERIC Educational Resources Information Center

    Kelley-Hall, Caren

    2010-01-01

    The purpose of this study was to explore the role of Student Support Services (SSS) in encouraging student involvement and its impact on student perceptions and academic experiences in three technical colleges in upstate South Carolina. By examining Alexander Astin's theory of student involvement in the services provided by the program, a better…

  9. Parent Involvement in Meaningful Post-School Experiences for Young Adults with IDD and Pervasive Support Needs

    ERIC Educational Resources Information Center

    Rossetti, Zachary; Lehr, Donna; Pelerin, Dana; Huang, Shuoxi; Lederer, Leslie

    2016-01-01

    Despite initiatives supporting young adults with intellectual and developmental disabilities (IDD) to engage in post-secondary education and integrated employment, those with more intensive support needs are not as easily involved in these post-school experiences. In an effort to learn from positive examples, we examined parent involvement in…

  10. Experience, Adoption, and Technology: Exploring the Phenomenological Experiences of Faculty Involved in Online Teaching at One School of Public Health

    ERIC Educational Resources Information Center

    Kidd, Terry; Davis, Trina; Larke, Patricia

    2016-01-01

    Using the Unified Theory of Acceptance and Use of Technology (UTAUT) and Dewey's Theory of Experience, this phenomenological study explored the experiences of faculty who engaged in online teaching at one school of public health. Findings revealed that the experiences of public health faculty, who engaged in online teaching, are similar and…

  11. 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

  12. 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.

  13. 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.

  14. Service user involvement in mental health assessment: comparing people's experiences of mental health triage assessments with theoretical perspectives on user involvement.

    PubMed

    Hird, Martin

    2007-09-01

    Separately, both user involvement and assessment are conceptually poorly defined by practitioners. Not surprisingly, reviews suggest that involvement in assessment is poorly researched, understood and largely achieved only at low levels. In this study fourteen service users and five assessors were interviewed, and a conceptual framework developed using grounded theory methods for data gathering and analysis. Two key dimensions of the experience emerged for involvement; the nature of the relationship with the assessor; and the construction of assessment as a process of dialogue. Recommendations for practice include: the use of an introductory letter to orientate service users to the assessment process; reconstructing the assessment as a series of encounters rather than as a single event; the provision of a written formulation to service users and; the introduction of systems to ensure that staff maintain their capacity for emotional reactivity to people presenting for this initial contact with mental health services.

  15. Intimate relationships and women involved in the sex trade: perceptions and experiences of inclusion and exclusion.

    PubMed

    Jackson, Lois A; Augusta-Scott, Tod; Burwash-Brennan, Marilee; Karabanow, Jeff; Robertson, Karyn; Sowinski, Barbara

    2009-01-01

    This article reports on a qualitative study exploring the intimate (non-work) relationships of women involved in the sex trade. Women working in the sex industry and intimate partners of women in the industry were interviewed in order to understand how intimate relationships are perceived as influencing the women's general health and well-being. The research suggests that intimate relationships can, and do, provide a space for feelings of inclusion and safety that are perceived as positive forces in women's general health and well-being. At the same time, however, feelings and experiences of exclusion (fuelled by the dominant stigmatizing discourse related to prostitution) can enter into intimate relationships, and are perceived as having a negative impact on the women's well-being, particularly their emotional health. Although there are attempts to keep the women's work separate from the intimate relationship, cross-over between the two spheres does occur. The research suggests that health care and service providers need to look beyond the women's working lives, and understand the relationships between work and home, as well as the ways in which intimate relationships can influence women's lives and health through both positive and negative forces.

  16. Psychiatric morbidity and people's experience of and response to social problems involving rights.

    PubMed

    Balmer, Nigel J; Pleasence, Pascoe; Buck, Alexy

    2010-11-01

    Psychiatric morbidity has been shown to be associated with the increased reporting of a range of social problems involving legal rights ('rights problems'). Using a validated measure of psychiatric morbidity, this paper explores the relationship between psychiatric morbidity and rights problems and discusses the implications for the delivery of health and legal services. New representative national survey data from the English and Welsh Civil and Social Justice Survey (CSJS) surveyed 3040 adults in 2007 to explore the relationship between GHQ-12 scores and the self reported incidence of and behaviour surrounding, rights problems. It was found that the prevalence of rights problems increased with psychiatric morbidity, as did the experience of multiple problems. It was also found the likelihood of inaction in the face of problems increased with psychiatric morbidity, while the likelihood of choosing to resolve problems without help decreased. Where advice was obtained, psychiatric morbidity was associated with a greater tendency to obtain a combination of 'legal' and 'general' support, rather than 'legal' advice alone. The results suggest that integrated and 'outreach' services are of particular importance to the effective support of those facing mental illness.

  17. Ocean Acoustic Observatory Federation

    DTIC Science & Technology

    2001-09-30

    J., C. G. Fox, and F. K. Duennebier, Hydroacoustic detection of submarine landslides on Kilauea volcano , Geophys. Res. Lett., vol. 28, 1811-1814...acoustic tomography experiments in the vicinity of coastal North America, • Monitor, in real time, marine mammals, earthquakes and volcanoes in the...distances, coastal tomography and thermometry, and earthquakes and volcanoes in the northern Pacific. APPROACH The members of the Ocean Acoustic

  18. Acoustic field modulation in regenerators

    NASA Astrophysics Data System (ADS)

    Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y.

    2016-12-01

    The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment.

  19. Propellant injection strategy for suppressing acoustic combustion instability

    NASA Astrophysics Data System (ADS)

    Diao, Qina

    Shear-coaxial injector elements are often used in liquid-propellant-rocket thrust chambers, where combustion instabilities remain a significant problem. A conventional solution to the combustion instability problem relies on passive control techniques that use empirically-developed hardware such as acoustic baffles and tuned cavities. In addition to adding weight and decreasing engine performance, these devices are designed using trial-and-error methods, which do not provide the capability to predict the overall system stability characteristics in advance. In this thesis, two novel control strategies that are based on propellant fluid dynamics were investigated for mitigating acoustic instability involving shear-coaxial injector elements. The new control strategies would use a set of controlled injectors allowing local adjustment of propellant flow patterns for each operating condition, particularly when instability could become a problem. One strategy relies on reducing the oxidizer-fuel density gradient by blending heavier methane with the main fuel, hydrogen. Another strategy utilizes modifying the equivalence ratio to affect the acoustic impedance through mixing and reaction rate changes. The potential effectiveness of these strategies was assessed by conducting unit-physics experiments. Two different model combustors, one simulating a single-element injector test and the other a double-element injector test, were designed and tested for flame-acoustic interaction. For these experiments, the Reynolds number of the central oxygen jet was kept between 4700 and 5500 making the injector flames sufficiently turbulent. A compression driver, mounted on one side of the combustor wall, provided controlled acoustic excitation to the injector flames, simulating the initial phase of flame-acoustic interaction. Acoustic excitation was applied either as band-limited white noise forcing between 100 Hz and 5000 Hz or as single-frequency, fixed-amplitude forcing at 1150 Hz

  20. Acoustic Imaging of Combustion Noise

    NASA Technical Reports Server (NTRS)

    Ramohalli, K. N.; Seshan, P. K.

    1984-01-01

    Elliposidal acoustic mirror used to measure sound emitted at discrete points in burning turbulent jets. Mirror deemphasizes sources close to target source and excludes sources far from target. At acoustic frequency of 20 kHz, mirror resolves sound from region 1.25 cm wide. Currently used by NASA for research on jet flames. Produces clearly identifiable and measurable variation of acoustic spectral intensities along length of flame. Utilized in variety of monitoring or control systems involving flames or other reacting flows.

  1. A Phenomenological Study of Parental Involvement and the Undergraduate College Student Experience

    ERIC Educational Resources Information Center

    Garrison, David Michael

    2013-01-01

    Parents highly involved in the academic lives of their college-going children have become increasingly common and yet the effect of such involvement on students is poorly understood by student services administrators and faculty. The purpose of this study was to better define the phenomenon of parental involvement in college through an…

  2. Ten Year Experience with Prosthetic Graft Infections Involving the Femoral Artery

    PubMed Central

    Siracuse, Jeffrey J; Nandivada, Prathima; Giles, Kristina A; Hamdan, Allen D; Wyers, Mark C; Chaikof, Elliot L; Pomposelli, Frank B; Schermerhorn, Marc L

    2013-01-01

    Background Prosthetic graft infection is a major complication of peripheral vascular surgery. We investigated our institution’s experience over ten years with bypass grafts involving the femoral artery to determine the incidence and risk factors for prosthetic graft infection. Methods A retrospective cohort single institution review of prosthetic bypass grafts involving the femoral artery from 2001–2010 evaluated patient demographics, body mass index, comorbidities, indications, location of bypass, type of prosthetic material, case urgency, previous ipsilateral bypass or percutaneous interventions; and evaluated the incidence of graft infections, amputations, and mortality. Results There were 496 prosthetic grafts identified with a graft infection rate of 3.8% (n=19) at a mean follow-up of 27 months. Multivariable analysis shows that redo bypass (HR 5.8, 95% CI 2.2–15.0), active infection at time of bypass (HR 5.2, 95% CI 1.9–14.2), female gender (HR 4.5, 95% CI 1.6–12.7), and diabetes mellitus (HR 4.6, 95% CI 1.5–14.3) were significant predictors of graft infection. Graft infection was predictive of major lower extremity amputation (HR 9.8, 95% CI 3.5–27.1) as was preoperative tissue loss (HR 4.7, 95% CI 1.8–11.9). Graft infection did not predict long term mortality, however chronic renal insufficiency (HR 2.3, 95% CI 1.6–3.4), tissue loss (HR 1.4, 95% CI 1.0–1.9), and active infection (HR 2.3, 95% CI 1.6–3.4) did. Infected grafts were removed 79% of the time. Staphylococcus epidermidis (37%) and Methicillin-sensitive Staphylococcus aureus (26%) were the most common pathogens isolated. Conclusions Redo-bypass, female gender, diabetes, and active infection at time of bypass are associated with a higher risk for prosthetic graft infection and major extremity amputation, but do not confer an increased risk of mortality. Autologous vein for lower extremity bypass and endovascular interventions should be considered when feasible in high

  3. Acoustics of a Nonhomogeneous Moving Medium.

    NASA Technical Reports Server (NTRS)

    Blokhintsev, D I

    1956-01-01

    Theoretical basis of the acoustics of a moving nonhomogeneous medium is considered in this report. Experiments that illustrate or confirm some of the theoretical explanation or derivation of these acoustics are also included.

  4. Perception of chemesthetic stimuli in groups who differ by food involvement and culinary experience

    PubMed Central

    Byrnes, Nadia; Loss, Christopher R.; Hayes, John E.

    2015-01-01

    In the English language, there is generally a limited lexicon when referring to the sensations elicited by chemesthetic stimuli like capsaicin, allyl isothiocyanate, and eugenol, the orally irritating compounds found in chiles, wasabi, and cloves, respectively. Elsewhere, experts and novices have been shown to use language differently, with experts using more precise language. Here, we compare perceptual maps and word usage across three cohorts: experts with formal culinary education, naïve individuals with high Food Involvement Scale (FIS) scores, and naïve individuals with low FIS scores. We hypothesized that increased experience with foods, whether through informal experiential learning or formal culinary education, would have a significant influence on the perceptual maps generated from a sorting task conducted with chemesthetic stimuli, as well as on language use in a descriptive follow-up task to this sorting task. The low- and highFIS non-expert cohorts generated significantly similar maps, though in other respects the highFIS cohort was an intermediate between the lowFIS and expert cohorts. The highFIS and expert cohorts generated more attributes but used language more idiosyncratically than the lowFIS group. Overall, the results from the expert group with formal culinary education differed from the two naïve cohorts both in the perceptual map generated using MDS as well as the mean number of attributes generated. Present data suggest that both formal education and informal experiential learning result in lexical development, but the level and type of learning can have a significant influence on language use and the approach to a sorting task. PMID:26516297

  5. Perception of chemesthetic stimuli in groups who differ by food involvement and culinary experience.

    PubMed

    Byrnes, Nadia; Loss, Christopher R; Hayes, John E

    2015-12-01

    In the English language, there is generally a limited lexicon when referring to the sensations elicited by chemesthetic stimuli like capsaicin, allyl isothiocyanate, and eugenol, the orally irritating compounds found in chiles, wasabi, and cloves, respectively. Elsewhere, experts and novices have been shown to use language differently, with experts using more precise language. Here, we compare perceptual maps and word usage across three cohorts: experts with formal culinary education, naïve individuals with high Food Involvement Scale (FIS) scores, and naïve individuals with low FIS scores. We hypothesized that increased experience with foods, whether through informal experiential learning or formal culinary education, would have a significant influence on the perceptual maps generated from a sorting task conducted with chemesthetic stimuli, as well as on language use in a descriptive follow-up task to this sorting task. The low- and highFIS non-expert cohorts generated significantly similar maps, though in other respects the highFIS cohort was an intermediate between the lowFIS and expert cohorts. The highFIS and expert cohorts generated more attributes but used language more idiosyncratically than the lowFIS group. Overall, the results from the expert group with formal culinary education differed from the two naïve cohorts both in the perceptual map generated using MDS as well as the mean number of attributes generated. Present data suggest that both formal education and informal experiential learning result in lexical development, but the level and type of learning can have a significant influence on language use and the approach to a sorting task.

  6. Acoustic mapping velocimetry

    NASA Astrophysics Data System (ADS)

    Muste, M.; Baranya, S.; Tsubaki, R.; Kim, D.; Ho, H.; Tsai, H.; Law, D.

    2016-05-01

    Knowledge of sediment dynamics in rivers is of great importance for various practical purposes. Despite its high relevance in riverine environment processes, the monitoring of sediment rates remains a major and challenging task for both suspended and bed load estimation. While the measurement of suspended load is currently an active area of testing with nonintrusive technologies (optical and acoustic), bed load measurement does not mark a similar progress. This paper describes an innovative combination of measurement techniques and analysis protocols that establishes the proof-of-concept for a promising technique, labeled herein Acoustic Mapping Velocimetry (AMV). The technique estimates bed load rates in rivers developing bed forms using a nonintrusive measurements approach. The raw information for AMV is collected with acoustic multibeam technology that in turn provides maps of the bathymetry over longitudinal swaths. As long as the acoustic maps can be acquired relatively quickly and the repetition rate for the mapping is commensurate with the movement of the bed forms, successive acoustic maps capture the progression of the bed form movement. Two-dimensional velocity maps associated with the bed form migration are obtained by implementing algorithms typically used in particle image velocimetry to acoustic maps converted in gray-level images. Furthermore, use of the obtained acoustic and velocity maps in conjunction with analytical formulations (e.g., Exner equation) enables estimation of multidirectional bed load rates over the whole imaged area. This paper presents a validation study of the AMV technique using a set of laboratory experiments.

  7. Pacific Hake Characteristics Affecting the Conduct of an Acoustic Clutter Experiment off the West Coast of the United States

    DTIC Science & Technology

    2012-07-04

    the assessment process. Echo sounder /trawl surveys of hake have been conducted by the National Marine Fisheries Service (NMFS) since 1977 to assess...3] There will be an NMFS hake survey in 2012. [20] The echo sounder /trawl method uses echo sounders to measure the total acoustic backscattering...NMFS echo sounder /trawl surveys have focused on fish age two or greater. Age-1 hake are generally more southerly and closer to shore than adults and

  8. 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.

  9. 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

  10. Addiction Treatment Experience among a Cohort of Street-Involved Youths and Young Adults

    ERIC Educational Resources Information Center

    Wong, Jellena; Marshall, Brandon D. L.; Kerr, Thomas; Lai, Calvin; Wood, Evan

    2009-01-01

    Very little is known about the accessibility and potential barriers to addiction treatment among street youths and young adults. We sought to examine the prevalence and correlates of enrollment in addiction treatment among a cohort of street-involved youths and young adults in Vancouver, Canada. Street-involved youths and young adults who use…

  11. Estimation of Effect Size from a Series of Experiments Involving Paired Comparisons.

    ERIC Educational Resources Information Center

    Gibbons, Robert D.; And Others

    1993-01-01

    A distribution theory is derived for a G. V. Glass-type (1976) estimator of effect size from studies involving paired comparisons. The possibility of combining effect sizes from studies involving a mixture of related and unrelated samples is also explored. Resulting estimates are illustrated using data from previous psychiatric research. (SLD)

  12. Recent victimization experiences and continued criminal behaviors: what are the links for adult drug-involved offenders?

    PubMed

    Zweig, Janine M; Yahner, Jennifer; Rossman, Shelli B

    2012-01-01

    Using data from the multi-site adult drug court evaluation (MADCE), we examined the relationship between recent victimization experiences and the likelihood of subsequent criminal behavior among a sample of adult drug-involved offenders. The MADCE data used in this study involved interviews with 674 men and 284 women at baseline and then, 18 months later. Multilevel modeling showed that physical victimizations in the year before baseline, but not sexual victimization experiences, were associated with self-reported criminal offending behavior 18 months later. All relationships held true despite controlling for respondents' demographic, criminal history, prior drug-related characteristics, and their participation in a drug court or comparison site program.

  13. Patient involvement in diabetes care: experiences in nine diabetes care groups

    PubMed Central

    de Bruin, Simone R.; Struijs, Jeroen N.; Rijken, Mieke; Nijpels, Giel; Baan, Caroline A.

    2015-01-01

    Introduction Despite the expected beneficial effects on quality of care, patient involvement in diabetes care groups, which deliver a bundled paid integrated care programme for diabetes type 2, seems to be limited. The aim of this study was to gain insight into levels and methods of patient involvement, into facilitators and barriers, and into the future preferences of care groups and patient representatives. Theory and methods Semi-structured interviews were held with 10 representatives of care groups and 11 representatives of patient advocacy groups. An adapted version of Arnstein's ladder of citizen participation was used to define five levels of patient involvement. Results Patient involvement in care groups was mostly limited to informing and consulting patients. Higher levels, i.e., advising, co-producing and decision-making, were less frequently observed. Care groups and patient representatives perceived largely the same barriers and facilitators and had similar preferences regarding future themes and design of patient involvement. Conclusion Constructive collaboration between diabetes care groups and patient representatives to enhance patient involvement in the future seems viable. Several issues such as the lack of evidence for effectiveness of patient involvement, differences in viewpoints on the role and responsibilities of care groups and perceived barriers need to be addressed. PMID:27118961

  14. Calculation of Critical Experiments involving U(37)O2F2 Solution

    SciTech Connect

    Goluoglu, K.L.

    2006-03-03

    Critical experiments were conducted at the Oak Ridge Critical Experiment Facility (ORCEF) to determine the critical concentration for an unreflected 69.2-cm-diameter sphere of UO{sub 2}F{sub 2}, at an enrichment of {approx}37 percent U{sup 235}, by weight. These experiments were a continuation of previous efforts to determine critical dimensions for fissile materials in simple geometry. Some of the earlier experiments in this vessel have been published as part of the OECD handbook. The reports concerning these experiments have only recently become available. Until August 2005, Refs. 2 and 3 were still classified. These documents, along with experimental logbooks and unclassified papers available on the experimental campaign and facility are being used to generate a computer model for this critical experiment.

  15. Central nervous system involvement in T-cell lymphoma: A single center experience.

    PubMed

    Gurion, Ronit; Mehta, Neha; Migliacci, Jocelyn C; Zelenetz, Andrew; Moskowitz, Alison; Lunning, Matthew; Moskowitz, Craig; Hamlin, Paul; Horwitz, Steven

    2016-05-01

    Background We characterized the incidence of central nervous system (CNS) involvement, risk factors and outcome in a large single institution dataset of peripheral T-cell lymphoma (PTCL). Methods Retrospective review of the PTCL database at Memorial Sloan Kettering Cancer Center. We identified 231 patients with any subtype of PTCL between 1994-2011 with a minimum six months of follow-up or an event defined as relapse or death. Results Histologies included peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS) (31.6%), angioimmunoblastic (16.9%), anaplastic large cell lymphoma (ALCL), ALK- (12.1%), ALCL, ALK + (6.1%), extranodal NK/T-cell lymphoma (7.4%), adult T-cell leukemia/lymphoma (ATLL) (7.4%), and transformed mycosis fungoides (8.7%). Seventeen patients had CNS disease (7%). Fifteen had CNS involvement with PTCL and two had diffuse large B-cell lymphoma and glioblastoma. Median time to CNS involvement was 3.44 months (0.16-103.1). CNS prophylaxis was given to 24 patients (primarily intrathecal methotrexate). Rates of CNS involvement were not different in patients who received prophylaxis. Univariate analysis identified stage III-IV, bone marrow involvement, >1 extranodal site and ATLL as risk factors for CNS disease. On multivariate analysis, >1 extranodal site and international prognostic index (IPI) ≥ 3 were predictive for CNS involvement. The median survival of patients with CNS involvement was 2.63 months (0.10-75). Conclusions Despite high relapse rates, PTCL, except ATLL, carries a low risk of CNS involvement. Prognosis with CNS involvement is poor and risk factors include: >1 extra nodal site and IPI ≥3.

  16. Introducing DIASCoPE: Directly Integrated Acoustic System Combined with Pressure Experiments — Changing the Paradigm from Product to Process

    NASA Astrophysics Data System (ADS)

    Whitaker, M. L.; Baldwin, K. J.; Huebsch, W. B.; Tercé, N.; Bejina, F.; Bystricky, M.; Chen, H.; Vaughan, M. T.; Weidner, D. J.

    2014-12-01

    Understanding the properties and behaviors of materials and multi-phase aggregates under conditions of high pressure and temperature is vital to unraveling the mysteries that lie beneath the surface of the planet. Advances in in situexperimental techniques using synchrotron radiation at these extreme conditions have helped to provide answers to fundamental questions that were previously unattainable. Synchrotron-based ultrasonic interferometry measurements have proven to be especially important in determining acoustic velocities and thermoelastic properties of materials at high pressures and temperatures. However, due to relatively slow data collection times, it has been difficult to measure the effects of processes as they occur, and instead the measurement is made on the end product of these processes. DIASCoPE is an important step toward addressing this problem.Over the last three years, we have designed and developed an on-board ultrasonic acoustic velocity measurement system that cuts data collection time down by over an order of magnitude. We can now measure P- and S-wave travel times in samples at extreme conditions in less than one second. Moreover, the system has been fully integrated with the multi-anvil apparatus and the EPICS control system at beamline X17B2 of the National Synchrotron Light Source, allowing for greater ease of control andfull automation of experimental data collection. The DIASCoPE has completed the testing and commissioning phase, and the first data collected using this powerful new system will be presented here.DIASCoPE represents a major step forward in acoustic velocity collection time reduction that will finally allow us to begin to witness what effects various processes in the deep Earth may have on the physical properties of materials at extreme conditions as they occur. These new capabilities will allow us to change the focus of study from the product to the process itself and will lead to a greater understanding of the

  17. Acoustic Blind Deconvolution and Frequency-Difference Beamforming in Shallow Ocean Environments

    DTIC Science & Technology

    2012-01-01

    sparse-array measurements might be used for this task. The long term goals of this project are: i) to determine the effectiveness of synthetic time...focused on developing an acoustic-ray-based version of synthetic time reversal (STR), a fully-passive technique for recovering the original signal and...simulations, b) verify these findings with simple airborne- or water-borne acoustic laboratory experiments involving multiple receivers and multiple ray paths

  18. A Classroom Experiment on Phase Equilibria Involving Orientational Disordering in Crystals.

    ERIC Educational Resources Information Center

    Mjojo, C. C.

    1985-01-01

    Background information, procedures used, and results obtained are provided for an experiment in which a phase diagram is determined using a differential scanning calorimeter. Commercial samples of D-camphoric anhydride (Eastman Kodak) and D,L-camphoric anhydride (Aldrich) were used in the experiment. (JN)

  19. A viable method to predict acoustic streaming in presence of cavitation.

    PubMed

    Louisnard, O

    2017-03-01

    The steady liquid flow observed under ultrasonic emitters generating acoustic cavitation can be successfully predicted by a standard turbulent flow calculation. The flow is driven by the classical averaged volumetric force density calculated from the acoustic field, but the inertial term in Navier-Stokes equations must be kept, and a turbulent solution must be sought. The acoustic field must be computed with a realistic model, properly accounting for dissipation by the cavitation bubbles [Louisnard, Ultrason. Sonochem., 19, (2012) 56-65]. Comparison with 20kHz experiments, involving the combination of acoustic streaming and a perpendicular forced flow in a duct, shows reasonably good agreement. Moreover, the persistence of the cavitation effects on the wall facing the emitter, in spite of the deflection of the streaming jet, is correctly reproduced by the model. It is also shown that predictions based either on linear acoustics with the correct turbulent solution, or with Louisnard's model with Eckart-Nyborg's theory yields unrealistic results.

  20. A Phenomenological Study of the Lived Experiences of Elementary Principals Involved in Dual-Career Relationships with Children

    ERIC Educational Resources Information Center

    Zeeck, Kirk A.

    2012-01-01

    This qualitative study examines the experiences of eight elementary principals from the Midwest who were involved in dual-career relationships with children under the age of 18. The primary data collection method was in-depth interviews. The data were coded and analyzed according to the research questions. The research resulted in three major…

  1. 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.

  2. Family Involvement in Children's Mathematics Education Experiences: Voices of Immigrant Chinese American Students and Their Parents

    ERIC Educational Resources Information Center

    Liang, Senfeng

    2013-01-01

    This study examines ways in which Chinese immigrant families are involved in their children's mathematics education, particularly focusing on how different types of families utilize different forms of capital to support their children's mathematics education. The theoretical framework defines four types of Chinese immigrant families--working…

  3. The Vocational Goals and Career Development of Criminally Involved Youth: Experiences That Help and Hinder

    ERIC Educational Resources Information Center

    Bartlett, Jennifer; Domene, José F.

    2015-01-01

    Little is known about the career development of youth with a history of criminal activity and the factors that influence their career development. The ability to secure employment is important in predicting successful outcomes for this population, but unfortunately youth who have been involved in crime are likely to face a myriad of obstacles to…

  4. The Experiences and Involvement of Grandparents in Hearing Detection and Intervention

    ERIC Educational Resources Information Center

    McNee, Chelsea M.; Jackson, Carla W.

    2012-01-01

    The purpose of this study was to examine the involvement of grandparents during hearing detection and intervention. Data were collected and analyzed from survey responses of 50 parents and 35 grandparents of children of varying ages who have hearing loss. Parents described important types of support that grandparents provided including frequent…

  5. Resident Involvement and Experience Do Not Affect Peri-Operative Complications Following Robotic Prostatectomy

    PubMed Central

    McMillan, Daniel T.; Viera, Anthony J.; Matthews, Jonathan; Raynor, Mathew C.; Woods, Michael E.; Pruthi, Raj S.; Wallen, Eric M.; Nielsen, Matthew E.; Smith, Angela B.

    2014-01-01

    Purpose Most urologic training programs use robotic prostatectomy (RP) as an introduction to teach residents appropriate robotic technique. However, concerns may exist regarding differences in RP outcomes with resident involvement. Our objective was therefore to evaluate whether resident involvement affects complications, operative time, or length of stay following RP. Methods Using the National Surgical Quality Improvement Program database (2005 – 2011), we identified patients who underwent RP, stratified them by resident presence or absence during surgery, and compared hospital length of stay (LOS), operative time, and postoperative complications using bivariable and multivariable analyses. A secondary analysis comparing outcomes of interest across postgraduate year (PGY) levels was also performed. Results 5,087 patients who underwent RPs were identified, in which residents participated in 56%, during the study period. After controlling for potential confounders, resident present and absent groups were similar in 30-day mortality (0.0% vs. 0.2%, p = 0.08), serious morbidity (1.8% vs. 2.1%, p = 0.33), and overall morbidity (5.1% vs. 5.4%, p = 0.70). While resident involvement did not affect LOS, operative time was longer when residents were present (median: 208 vs. 183 minutes, p < 0.001). Similar findings were noted when assessing individual PGY levels. Conclusions Regardless of PGY level, resident involvement in RPs appears safe and does not appear to affect postoperative complications or length of stay. While resident involvement in RPs does result in longer operative times, this is necessary for the learning process. PMID:24985554

  6. Observations of premonitory acoustic emission and slip nucleation during a stick slip experiment in smooth faulted Westerly granite

    USGS Publications Warehouse

    Thompson, B.D.; Young, R.P.; Lockner, D.A.

    2005-01-01

    To investigate laboratory earthquakes, stick-slip events were induced on a saw-cut Westerly granite sample by triaxial loading at 150 MPa confining pressure. Acoustic emissions (AE) were monitored using an innovative continuous waveform recorder. The first motion of each stick slip was recorded as a large-amplitude AE signal. These events source locate onto the saw-cut fault plane, implying that they represent the nucleation sites of the dynamic failure stick-slip events. The precise location of nucleation varied between events and was probably controlled by heterogeneity of stress or surface conditions on the fault. The initial nucleation diameter of each dynamic instability was inferred to be less than 3 mm. A small number of AE were recorded prior to each macro slip event. For the second and third slip events, premonitory AE source mechanisms mimic the large scale fault plane geometry. Copyright 2005 by the American Geophysical Union.

  7. Diffusion with chemical reaction: An attempt to explain number density anomalies in experiments involving alkali vapor

    NASA Technical Reports Server (NTRS)

    Snow, W. L.

    1974-01-01

    The mutual diffusion of two reacting gases is examined which takes place in a bath of inert gas atoms. Solutions are obtained between concentric spheres, each sphere acting as a source for one of the reactants. The calculational model is used to illustrate severe number density gradients observed in absorption experiments with alkali vapor. Severe gradients result when sq root k/D R is approximately 5 where k, D, and R are respectively the second order rate constant, the multicomponent diffusion constant, and the geometrical dimension of the experiment.

  8. Relapsing Polychondritis with Central Nervous System Involvement: Experience of Three Different Cases in a Single Center.

    PubMed

    Jeon, Chan Hong

    2016-11-01

    Relapsing polychondritis (RP) is an autoimmune disorder characterized by inflammation in cartilaginous structures including the ears, noses, peripheral joints, and tracheobronchial tree. It rarely involves the central nervous system (CNS) but diagnosis of CNS complication of RP is challenging because it can present with varying clinical features. Herein we report 3 cases of relapsing polychondritis involving CNS with distinct manifestations and clinical courses. The first patient presented with rhombencephalitis resulting in brain edema and death. The second patient had acute cognitive dysfunction due to limbic encephalitis. He was treated with steroid pulse therapy and recovered without sequelae. The third patient suffered aseptic meningitis that presented as dementia, which was refractory to steroid and immune suppressive agents. We also reviewed literature on CNS complications of RP.

  9. Relapsing Polychondritis with Central Nervous System Involvement: Experience of Three Different Cases in a Single Center

    PubMed Central

    2016-01-01

    Relapsing polychondritis (RP) is an autoimmune disorder characterized by inflammation in cartilaginous structures including the ears, noses, peripheral joints, and tracheobronchial tree. It rarely involves the central nervous system (CNS) but diagnosis of CNS complication of RP is challenging because it can present with varying clinical features. Herein we report 3 cases of relapsing polychondritis involving CNS with distinct manifestations and clinical courses. The first patient presented with rhombencephalitis resulting in brain edema and death. The second patient had acute cognitive dysfunction due to limbic encephalitis. He was treated with steroid pulse therapy and recovered without sequelae. The third patient suffered aseptic meningitis that presented as dementia, which was refractory to steroid and immune suppressive agents. We also reviewed literature on CNS complications of RP. PMID:27709866

  10. Student International Research Project on Employees' Involvement in Innovation: Experience and Outcomes

    ERIC Educational Resources Information Center

    Bondarev, Maxim; Zashchitina, Elena; Andreassen, John-Erik

    2016-01-01

    This paper represents the experience and outcomes of a joint education and research project of Østfold University College and Southern Federal University. The project goal is to evolve and strengthen the academic cooperation between the universities by developing joint courses and improving the quality of education via mutual exchange of…

  11. A Model for Engaging Students in a Research Experience Involving Variational Techniques, Mathematica, and Descent Methods.

    ERIC Educational Resources Information Center

    Mahavier, W. Ted

    2002-01-01

    Describes a two-semester numerical methods course that serves as a research experience for undergraduate students without requiring external funding or the modification of current curriculum. Uses an engineering problem to introduce students to constrained optimization via a variation of the traditional isoperimetric problem of finding the curve…

  12. Involved Parents' Perceptions of Their Experiences in School-Based Team Meetings

    ERIC Educational Resources Information Center

    Esquivel, Shelley L.; Ryan, Carey S.; Bonner, Mike

    2008-01-01

    We explored parents' perceptions of their positive and negative experiences in school-based team meetings as a first step toward identifying the characteristics that may promote meaningful parent participation. Parent members of a Midwestern suburban school district's special education advisory group provided open-ended descriptions of their…

  13. Labor Force Experiences of a National Sample of Young Adult Men: The Role of Drug Involvement.

    ERIC Educational Resources Information Center

    Kandel, Denise B.; Davies, Mark

    1990-01-01

    Investigates the effects of the use of cigarettes, alcohol, marijuana, and cocaine on the following aspects of labor force experience: (1) earnings; (2) stability of employment; (3) gaps between employment spells; and (4) duration of unemployment. Illicit drug use was found to have an impact on all factors except earnings. (JS)

  14. Classroom-to-Home Connections: Young Children's Experiences with a Technology-Based Parent Involvement Tool

    ERIC Educational Resources Information Center

    Walsh, Bridget A.; Cromer, Heidi; Weigel, Daniel J.

    2014-01-01

    Research Findings: DVD classroom newsletters are one proposed technology tool to promote classroom-to-home connections. The present study explored the experiences of prekindergarten children from predominantly Spanish-speaking homes with bilingual (English and Spanish) DVD classroom newsletters. On average, parents reported that children watched…

  15. Opto-acoustic diagnostics of the thermal action of high-intensity focused ultrasound on biological tissues: the possibility of its applications and model experiments

    SciTech Connect

    Khokhlova, Tanya D; Pelivanov, Ivan M; Solomatin, Vladimir S; Karabutov, Aleksander A; Sapozhnikov, Oleg A

    2006-12-31

    The possibility of using the opto-acoustic (OA) method for monitoring high-intensity ultrasonic therapy is studied. The optical properties of raw and boiled liver samples used as the undamaged model tissue and tissue destroyed by ultrasound, respectively, are measured. Experiments are performed with samples consisting of several alternating layers of raw and boiled liver of different thickness. The position and transverse size of the thermal lesion were determined from the temporal shape of the OA signals. The results of measurements are compared with the real size and position of the thermal lesion determined from the subsequent cuts of the sample. It is shown that the OA method permits the diagnostics of variations in biological tissues upon ultrasonic therapy. (special issue devoted to multiple radiation scattering in random media)

  16. Giant congenital intercostal arteriovenous malformation with extensive involvement of chest wall and ribs: surgical experience.

    PubMed

    Parashi, Hrishikesh Sukhadeo; Bhosle, Krishnarao Narayan; Thakare, Nitin Dashrath; Sharma, Ajay; Potwar, Sushrut Suhas

    2013-06-01

    Intercostal arteriovenous malformations (AVMs) are rare lesions. Review of literature shows that most reported cases are secondary to trauma or iatrogenic in origin. Congenital intercostal AVMs are extremely rare. We believe that only 1 case report of congenital intercostal arteriovenous malformation has been reported previously in the literature. We present an exceedingly rare case of giant congenital intercostal AVM in a young patient diagnosed on contrast-enhanced computed tomography of the thorax and treated by surgical resection of the involved chest wall and ribs with reconstruction of the surgical defect.

  17. Behcet’s disease and cardiovascular involvement: our experience of asymptomatic Behcet’s patients

    PubMed Central

    Ulusan, Zeynep; Karadag, Ayse Serap; Tasar, Mehmet; Kalender, Mehmet; Tansel Darcin, Osman

    2014-01-01

    Summary Abstract Behcet’s syndrome is a systemic inflammatory disease associated with vasculitis, and arterial, venous and cardiac disorders. Thirty-eight Behcet’s disease patients were examined prospectively with echocardiography, ultrasonography and computed tomography, and coagulation parameters were determined. Deep venous insufficiency was found in 16 patients, venous thrombosis in seven, one patient had iliac artery stenosis, three had carotid arterial intimal proliferation, two patients had aortic annulus dilatation, six had aortic valve insufficiency, and three had mitral valve insufficiency. None had coagulation defects. To decrease morbidity and mortality rates, a multidisciplinary approach is important for early diagnosis of cardiovascular involvement in Behcet’s disease. PMID:24844550

  18. 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.

  19. Acoustic-emission monitoring of steam turbines

    NASA Astrophysics Data System (ADS)

    Graham, L. J.; Randall, R. L.; Hong, C.

    1982-04-01

    A method for the on-line detection of crack growth in steam turbine rotors based on acoustic emission (AE) monitoring is discussed. A systematic study involving a number of tasks was performed to evaluate the potential for the detection and correct identification of crack growth AE signals during various turbine operating conditions. These included acoustic wave propagation and attenuation measurements, background noise characterization, laboratory rotor material tests, monitoring equipment optimization, dynamic stress analysis of the rotor under transient operation and on-line source location and signal characterization. No crack growth was detected during the monitoring periods but there was sufficient information from the combined tasks to estimate the flaw growth detectability during different operating conditions if it occurs. The experience also suggests that AE monitoring can be useful for diagnosis of other turbine problems such as blade rubbing, out-of-balance condition, bearing deterioration, lubricating oil contamination and perhaps boiler exfoliation and blade erosion.

  20. Advantages of laser-acoustical leak testing for construction and operation of low-temperature installations and superconducting experiments

    NASA Astrophysics Data System (ADS)

    Herz, W.

    2002-09-01

    At the Institute of Technical Physics of the Research Center Karlsruhe, superconducting magnets for nuclear fusion applications have been tested in the vacuum tank TOSKA for more than 20 years. A crucial test parameter of the magnet coils (mass up to 120 metric tons) as well as of the peripheral components, such as current leads (up to 80 kA), helium refrigerators (2 kW), and low-temperature transfer lines (length approx200 m), is their vacuum tightness at operating conditions (minimum temperature approx2 K, maximum refrigerant pressure 25 bar). Because the final tests at cryotemperature are costly and time consuming, intermediate tests at room temperature have already been performed at the stages of manufacturing, certification, and assembling, and prior to cooldown. So far, these tightness tests have been performed with probe gas helium employing a conventional mass spectrometer leak detector, whereby the smallest detectable leakage is limited by the He partial pressure in the surrounding air. Therefore, a new technique of leak measurement was investigated using the probe gas sulfur hexafluoride SF6, which does not occur in natural air, and which can be sensitively detected by a laser-acoustical leak detector. The obtained experimental results reveal the substantial advantages of the new method with respect to detection sensitivity, testing expenditure, and costs. The results can be transferred to tightness tests in other fields of technology. copyright 2002 American Vacuum Society.

  1. NSTA-NASA Shuttle Student Involvement Project. Experiment Results: Insect Flight Observation at Zero Gravity

    NASA Technical Reports Server (NTRS)

    Nelson, T. E.; Peterson, J. R.

    1982-01-01

    The flight responses of common houseflies, velvetbean caterpillar moths, and worker honeybees were observed and filmed for a period of about 25 minutes in a zero-g environment during the third flight of the Space Shuttle Vehicle (flight number STS-3; March 22-30, 1982). Twelve fly puparia, 24 adult moths, 24 moth pupae, and 14 adult bees were loaded into an insect flight box, which was then stowed aboard the Shuttle Orbiter, the night before the STS-3 launch at NASA's Kennedy Space Center (KSC). The main purpose of the experiment was to observe and compare the flight responses of the three species of insects, which have somewhat different flight control mechanisms, under zero-g conditions.

  2. Definition Study for Space Shuttle Experiments Involving Large, Steerable Millimeter-Wave Antenna Arrays

    NASA Technical Reports Server (NTRS)

    Levis, C. A.

    1976-01-01

    The potential uses and techniques for the shuttle spacelab Millimeter Wave Large Aperture Antenna Experiment (MWLAE) are documented. Potential uses are identified: applications to radio astronomy, the sensing of atmospheric turbulence by its effect on water vapor line emissions, and the monitoring of oil spills by multifrequency radiometry. IF combining is preferable to RF combining with respect to signal to noise ratio for communications receiving antennas of the size proposed for MWLAE. A design approach using arrays of subapertures is proposed to reduce the number of phase shifters and mixers for uses which require a filled aperture. Correlation radiometry and a scheme utilizing synchronous Dicke switches and IF combining are proposed as potential solutions.

  3. Results of Ionospheric Heating Experiments Involving an Enhancement in Electron Density in the High Latitude Ionosphere

    NASA Astrophysics Data System (ADS)

    Wu, Jun; Wu, Jian; Xu, Zhengwen

    2016-09-01

    Observations are presented of the phenomenon of the enhancement in electron density and temperature that is caused by a powerful pump wave at a frequency near the fifth gyrofrequency. The observations show that the apparent enhancement in electron density extending over a wide altitude range and the enhancement in electron temperature around the reflection altitude occur as a function of pump frequency. Additionally, the plasma line spectra show unusual behavior as a function of pump frequency. In conclusion, the upper hybrid wave resonance excited by the pump wave plays a dominating role and leads to the enhancement in electron temperature at the upper hybrid altitude. The phenomenon of apparent enhancement in electron density does not correspond to the true enhancement in electron density, this may be due to some mechanism that preferentially involves the plasma transport process and leads to the strong backscatter of radar wave along the magnetic line, which remains to be determined. supported by National Natural Science Foundation of China (No. 40831062)

  4. Accelerators for critical experiments involving single-particle upset in solid-state microcircuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1985-01-01

    Charged-particle interactions in microelectronic circuit chips (integrated circuits) present a particularly insidious problem for solid-state electronic systems due to the generation of soft errors or single-particle event upset (SEU) by either cosmic rays or other radiation sources. Particle accelerators are used to provide both light and heavy ions in order to assess the propensity of integrated circuit chips for SEU. Critical aspects of this assessment involve the ability to analytically model SEU for the prediction of error rates in known radiation environments. In order to accurately model SEU, the measurement and prediction of energy deposition in the form of an electron-hole plasma generated along an ion track is of paramount importance. This requires the use of accelerators which allow for ease in both energy control (change of energy) and change of ion species. This and other aspects of ion-beam control and diagnostics (e.g., uniformity and flux) are of critical concern for the experimental verification of theoretical SEU models.

  5. Clinical characteristics of primary peritoneal carcinoma patients: a single-institution experience involving 8 patients

    PubMed Central

    Hattori, Satomi; Kajiyama, Hiroaki; Fuji, Utako; Furui, Yuko; Ishibashi, Yuki; Hattori, Yuka; Takahashi, Noriko; Kikkawa, Fumitaka; Misawa, Toshiya

    2016-01-01

    ABSTRACT Primary peritoneal carcinoma (PPC) is treated similarly to advanced epithelial ovarian carcinoma (aEOC); however, the standard approach for the management of PPC is controversial. The objective of this study was to evaluate the clinical features and prognosis of those patients. A retrospective analysis was performed of eight patients with PPC between January 2008 and December 2015. Clinicopathologic parameters, the diagnostic modality, treatment, and oncologic outcome were analyzed. The median age at the time of diagnosis was 72.5 years (range: 55–79), with a median follow-up of 26.5 months (range, 5–74). Most of the PPC developed with carcinomatosis peritonei involving ascites, while some cases developed sporadically in the peritoneal or extraperitoneal cavity without ascites. The most common initial symptom was abdominal fullness, and other symptoms were inguinal tumor, paralysis of the extremities, and respiratory disorder. The preoperative CA125 value was elevated in all patients. In four patients who did not undergo primary surgery, the final diagnoses were determined by the ascites cytology and radiological image. Initial or interval debulking surgery was performed in only two patients. All patients were treated with paclitaxel or docetaxel plus carboplatin. Five showed a complete response (CR), and one showed a partial response (PR). Among the five patients with CR, the median progression-free and overall survival periods were 15 (12–26) and 41.5 (32–74) months, respectively. Three patients without carcinomatosis peritonei showed a relatively favorable prognosis. The management of PPC is generally consistent with that of aEOC; however, in atypical cases, the treatment method should be considered individually. PMID:28008196

  6. 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.

  7. 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

  8. 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.

  9. Psychosocial experiences of breast cancer survivors involved in a dragon boat program: exploring links to positive psychological growth.

    PubMed

    Sabiston, Catherine M; McDonough, Meghan H; Crocker, Peter R E

    2007-08-01

    This study explored psychosocial experiences of breast cancer survivors involved in dragon boat programs. Twenty women (M(age) = 58.69, SD = 6.85) were interviewed for 45-60 min about their experiences as members of survivor dragon boat teams. Interviews were analyzed using constructivist grounded theory methods. The dragon boat program facilitated social support from women with common challenges and a shared understanding of survivorship. It also provided opportunities to (re)gain a sense of personal control, develop new identities as athletes, and overcome physical challenges. Together these elements contributed to positive psychological growth and linked to the literature on posttraumatic growth. Future physical activity interventions targeting breast cancer survivors may benefit from developing strategies that share key characteristics of dragon boating.

  10. Masculinity and the body: how African American and White men experience cancer screening exams involving the rectum.

    PubMed

    Winterich, Julie A; Quandt, Sara A; Grzywacz, Joseph G; Clark, Peter E; Miller, David P; Acuña, Joshua; Arcury, Thomas A

    2009-12-01

    Past research on prostate and colorectal cancer disparities finds that barriers to screening, such as embarrassment and offensiveness, are often reported. Yet none of this literature investigates why. This study uses masculinity and health theory to examine how men experience two common screenings: digital rectal exams (DREs) and colonoscopies. In-depth interviews were conducted with 64 African American and White men from diverse backgrounds, aged 40 to 64, from North Carolina. Regardless of race or education, men experienced DREs more negatively than colonoscopies because penetration with a finger was associated with a gay sexual act. Some men disliked colonoscopies, however, because they associated any penetration as an affront to their masculinity. Because beliefs did not differ by race, future research should focus on structural issues to examine why disparities persist with prostate and colorectal cancer. Recommendations are provided for educational programs and physicians to improve men's experiences with exams that involve the rectum.

  11. Asymptotic Analysis of Ocean Bottom Reflected Acoustic Fields.

    DTIC Science & Technology

    1984-05-01

    dependence(e-i’t), the reflected spatial part of the acoustic pressure field P in a homogeneous medium due to a point source placed in that medium...reasonable to assume that the water colunm is homogeneous , especially for experiments which involve small source and receiver heights. In many abyssal plain...configuration, a homogeneous layer between two homo- eneous halfspaces. Using a modified uniform asymptotic method, Stickler and Ahluwalia[12] obtained

  12. 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.

  13. Endoscopic ultrasound-guided fine-needle aspiration diagnosis of secondary tumors involving the pancreas: An institution's experience

    PubMed Central

    Alomari, Almed K.; Ustun, Berrin; Aslanian, Harry R.; Ge, Xinquan; Chhieng, David; Cai, Guoping

    2016-01-01

    Background: Pancreatic masses may seldom represent a metastasis or secondary involvement by lymphoproliferative disorders. Recognition of this uncommon occurrence may help render an accurate diagnosis and avoid diagnostic pitfalls during endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). In this study, we review our experience in diagnosing secondary tumors involving the pancreas. Materials and Methods: The electronic database of cytopathology archives was searched for cases of secondary tumors involving the pancreas at our institution and a total of 31 cases were identified. The corresponding clinical presentations, imaging study findings, cytological diagnoses, the results of ancillary studies, and surgical follow-up, if available, were reviewed. Results: Nineteen of the patients were male and 12 female, with a mean age of 66 years. Twenty-three patients (74%) had a prior history of malignancy, with the latency ranging from 6 months to 19 years. The secondary tumors involving the pancreas included metastatic carcinoma (24 cases), metastatic sarcoma (3 cases), diffuse large B-cell lymphoma (2 cases), and plasma cell neoplasm (2 cases). The most common metastatic tumors were renal cell carcinoma (8 cases) and lung carcinoma (7 cases). Correct diagnoses were rendered in 29 cases (94%). The remaining two cases were misclassified as primary pancreatic carcinoma. In both cases, the patients had no known history of malignancy, and no ancillary studies were performed. Conclusions: Secondary tumors involving the pancreas can be accurately diagnosed by EUS-FNA. Recognizing uncommon cytomorphologic features, knowing prior history of malignancy, and performing ancillary studies are the keys to improve diagnostic performance and avoid diagnostic pitfalls. PMID:26955395

  14. The Simplest Demonstration on Acoustic Beats

    ERIC Educational Resources Information Center

    Ganci, Alessio; Ganci, Salvatore

    2015-01-01

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

  15. Attitudes toward hiring applicants with mental illness and criminal justice involvement: the impact of education and experience.

    PubMed

    Batastini, Ashley B; Bolanos, Angelea D; Morgan, Robert D

    2014-01-01

    Individuals with mental health diagnoses, as well as those involved in the criminal justice system, experience a number of barriers in the recovery and reintegration progress, including access to stable, prosocial employment opportunities. Employment for these populations is important for establishing financial security, reducing unstructured leisure time, increasing self-worth, and improving interpersonal skills. However, research has demonstrated that individuals with psychiatric and/or criminal backgrounds may experience stigmatizing attitudes from employers that impede their ability to find adequate work. This study aimed to evaluate stigmatizing beliefs toward hypothetical applicants who indicated a mental health history, a criminal history, or both, as well as the effectiveness of psychoeducation in reducing stigma. Participants consisted of 465 individuals recruited from a large university who completed a series of online questions about a given applicant. Results of this study varied somewhat across measures of employability, but were largely consistent with extant research suggesting that mental illness and criminal justice involvement serve as deterrents when making hiring decisions. Overall, psychoeducation appeared to reduce stigma for hiring decisions when the applicant presented with a criminal history. Unfortunately, similar findings were not revealed when applicants presented with a psychiatric or a psychiatric and criminal history. Implications and limitations of these findings are presented, along with suggestions for future research.

  16. Low-Frequency Acoustic Propagation Loss in the Arctic Ocean: Results of the Arctic Climate Observations using Underwater Sound Experiment

    DTIC Science & Technology

    2004-03-05

    experiment on the Turpan-SIMI path, but much smaller than those measured on the Turpan- Narwhal path which was almost coincident with the 1000-km section of...the ACOUS path from the Nansen Basin to the Lincoln Sea. The integral propagation loss on the path to Narwhal was about 30 dB for mode 1 and 10-13 dB

  17. 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.

  18. 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

  19. Acoustic studies for alpha background rejection in dark matter bubble chamber detectors

    SciTech Connect

    Bou-Cabo, M.; Felis, I.; Ardid, M.; Collaboration: COUPP Collaboration

    2013-08-08

    COUPP (Chicagoland Observatory for Underground Particle Physics) is an experiment with bubble chambers able to detect dark matter directly either with Spin-Dependent or with Spin-Independent interactions. The target material is a superheated liquid (usually CF3I) that can be bubble nucleated due to nuclear recoils produced by elastic collisions of dark matter particles. The bubble growth inside the chamber is accompanied with an acoustic signature. The acoustic technique has been successfully used to have a good alpha discrimination (about 99%). In this paper, we present different studies and results related with the characterization of the acoustic properties of the detector and the different phenomena involved in the acoustic measurements of the bubble growth, such as sound generation, sound transmission and optimization of piezoelectric transducers.

  20. Low-frequency target strength and abundance of shoaling Atlantic herring (Clupea harengus) in the Gulf of Maine during the Ocean Acoustic Waveguide Remote Sensing 2006 Experiment.

    PubMed

    Gong, Zheng; Andrews, Mark; Jagannathan, Srinivasan; Patel, Ruben; Jech, J Michael; Makris, Nicholas C; Ratilal, Purnima

    2010-01-01

    The low-frequency target strength of shoaling Atlantic herring (Clupea harengus) in the Gulf of Maine during Autumn 2006 spawning season is estimated from experimental data acquired simultaneously at multiple frequencies in the 300-1200 Hz range using (1) a low-frequency ocean acoustic waveguide remote sensing (OAWRS) system, (2) areal population density calibration with several conventional fish finding sonar (CFFS) systems, and (3) low-frequency transmission loss measurements. The OAWRS system's instantaneous imaging diameter of 100 km and regular updating enabled unaliased monitoring of fish populations over ecosystem scales including shoals of Atlantic herring containing hundreds of millions of individuals, as confirmed by concurrent trawl and CFFS sampling. High spatial-temporal coregistration was found between herring shoals imaged by OAWRS and concurrent CFFS line-transects, which also provided fish depth distributions. The mean scattering cross-section of an individual shoaling herring is found to consistently exhibit a strong, roughly 20 dB/octave roll-off with decreasing frequency in the range of the OAWRS survey over all days of the roughly 2-week experiment, consistent with the steep roll-offs expected for sub-resonance scattering from fish with air-filled swimbladders.

  1. Structural-acoustic model of a rectangular plate-cavity system with an attached distributed mass and internal sound source: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Pirnat, Miha; Čepon, Gregor; Boltežar, Miha

    2014-03-01

    In this paper three approaches are combined to develop a structural-acoustic model of a rectangular plate-cavity system with an attached distributed mass and internal sound source. The first approach results from a recently presented analysis based on the Rayleigh-Ritz method and is used to circumvent the difficulties in obtaining the natural frequencies and mode shapes of a plate with an attached, distributed mass. Furthermore, different plate boundary conditions can be accommodated. The resulting mode shapes are defined as continuous functions; this is advantageous as they can be directly used in the second approach, i.e., the classic modal-interaction approach in order to obtain the coupled equations of the system. Finally, in the third approach a group of point sources emitting a pressure pulse in the time domain is used to model an internal sound source. For the validation of the developed model an experiment was conducted in two configurations using a simply supported aluminium plate and a clamped plate coupled with a plexiglas box containing a loudspeaker. Good agreement was found between the analytical and experimental data.

  2. Acoustic asymmetric transmission based on time-dependent dynamical scattering

    NASA Astrophysics Data System (ADS)

    Wang, Qing; Yang, Yang; Ni, Xu; Xu, Ye-Long; Sun, Xiao-Chen; Chen, Ze-Guo; Feng, Liang; Liu, Xiao-Ping; Lu, Ming-Hui; Chen, Yan-Feng

    2015-06-01

    An acoustic asymmetric transmission device exhibiting unidirectional transmission property for acoustic waves is extremely desirable in many practical scenarios. Such a unique property may be realized in various configurations utilizing acoustic Zeeman effects in moving media as well as frequency-conversion in passive nonlinear acoustic systems and in active acoustic systems. Here we demonstrate a new acoustic frequency conversion process in a time-varying system, consisting of a rotating blade and the surrounding air. The scattered acoustic waves from this time-varying system experience frequency shifts, which are linearly dependent on the blade’s rotating frequency. Such scattering mechanism can be well described theoretically by an acoustic linear time-varying perturbation theory. Combining such time-varying scattering effects with highly efficient acoustic filtering, we successfully develop a tunable acoustic unidirectional device with 20 dB power transmission contrast ratio between two counter propagation directions at audible frequencies.

  3. Acoustic asymmetric transmission based on time-dependent dynamical scattering

    PubMed Central

    Wang, Qing; Yang, Yang; Ni, Xu; Xu, Ye-Long; Sun, Xiao-Chen; Chen, Ze-Guo; Feng, Liang; Liu, Xiao-ping; Lu, Ming-Hui; Chen, Yan-Feng

    2015-01-01

    An acoustic asymmetric transmission device exhibiting unidirectional transmission property for acoustic waves is extremely desirable in many practical scenarios. Such a unique property may be realized in various configurations utilizing acoustic Zeeman effects in moving media as well as frequency-conversion in passive nonlinear acoustic systems and in active acoustic systems. Here we demonstrate a new acoustic frequency conversion process in a time-varying system, consisting of a rotating blade and the surrounding air. The scattered acoustic waves from this time-varying system experience frequency shifts, which are linearly dependent on the blade’s rotating frequency. Such scattering mechanism can be well described theoretically by an acoustic linear time-varying perturbation theory. Combining such time-varying scattering effects with highly efficient acoustic filtering, we successfully develop a tunable acoustic unidirectional device with 20 dB power transmission contrast ratio between two counter propagation directions at audible frequencies. PMID:26038886

  4. Advanced Broadband Acoustic Clutter

    DTIC Science & Technology

    2010-10-31

    7, 18]). Key result: despite some claims to the contrary in the ocean acoustics community, sub-bottom clutter can and does occur in shallow water ...propagation, and clutter in both theory and measurements. This is important because in some shallow water areas (especially those with significant riverine...Abraham, data from Clutter󈧋 Experiment) to examine dependence of clutter statistics on multipath (Ref [8]). Key result: in the shallow water

  5. Three-dimensional manipulation of single cells using surface acoustic waves.

    PubMed

    Guo, Feng; Mao, Zhangming; Chen, Yuchao; Xie, Zhiwei; Lata, James P; Li, Peng; Ren, Liqiang; Liu, Jiayang; Yang, Jian; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2016-02-09

    The ability of surface acoustic waves to trap and manipulate micrometer-scale particles and biological cells has led to many applications involving "acoustic tweezers" in biology, chemistry, engineering, and medicine. Here, we present 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the capture and manipulation of microparticles and cells along three mutually orthogonal axes. In this method, we use standing-wave phase shifts to move particles or cells in-plane, whereas the amplitude of acoustic vibrations is used to control particle motion along an orthogonal plane. We demonstrate, through controlled experiments guided by simulations, how acoustic vibrations result in micromanipulations in a microfluidic chamber by invoking physical principles that underlie the formation and regulation of complex, volumetric trapping nodes of particles and biological cells. We further show how 3D acoustic tweezers can be used to pick up, translate, and print single cells and cell assemblies to create 2D and 3D structures in a precise, noninvasive, label-free, and contact-free manner.

  6. Three-dimensional manipulation of single cells using surface acoustic waves

    PubMed Central

    Guo, Feng; Mao, Zhangming; Chen, Yuchao; Xie, Zhiwei; Lata, James P.; Li, Peng; Ren, Liqiang; Liu, Jiayang; Yang, Jian; Dao, Ming; Suresh, Subra; Huang, Tony Jun

    2016-01-01

    The ability of surface acoustic waves to trap and manipulate micrometer-scale particles and biological cells has led to many applications involvingacoustic tweezers” in biology, chemistry, engineering, and medicine. Here, we present 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the capture and manipulation of microparticles and cells along three mutually orthogonal axes. In this method, we use standing-wave phase shifts to move particles or cells in-plane, whereas the amplitude of acoustic vibrations is used to control particle motion along an orthogonal plane. We demonstrate, through controlled experiments guided by simulations, how acoustic vibrations result in micromanipulations in a microfluidic chamber by invoking physical principles that underlie the formation and regulation of complex, volumetric trapping nodes of particles and biological cells. We further show how 3D acoustic tweezers can be used to pick up, translate, and print single cells and cell assemblies to create 2D and 3D structures in a precise, noninvasive, label-free, and contact-free manner. PMID:26811444

  7. 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.

  8. Turbofan Acoustic Propagation and Radiation

    NASA Technical Reports Server (NTRS)

    Eversman, Walter

    2000-01-01

    This document describes progress in the development of finite element codes for the prediction of near and far field acoustic radiation from the inlet and aft fan ducts of turbofan engines. The report consists of nine papers which have appeared in archival journals and conference proceedings, or are presently in review for publication. Topics included are: 1. Aft Fan Duct Acoustic Radiation; 2. Mapped Infinite Wave Envelope Elements for Acoustic Radiation in a Uniformly Moving Medium; 3. A Reflection Free Boundary Condition for Propagation in Uniform Flow Using Mapped Infinite Wave Envelope Elements; 4. A Numerical Comparison Between Multiple-Scales and FEM Solution for Sound Propagation in Lined Flow Ducts; 5. Acoustic Propagation at High Frequencies in Ducts; 6. The Boundary Condition at an Impedance Wall in a Nonuniform Duct with Potential Flow; 7. A Reverse Flow Theorem and Acoustic Reciprocity in Compressible Potential Flows; 8. Reciprocity and Acoustics Power in One Dimensional Compressible Potential Flows; and 9. Numerical Experiments on Acoustic Reciprocity in Compressible Potential Flows.

  9. West Texas array experiment: Noise and source characterization of short-range infrasound and acoustic signals, along with lab and field evaluation of Intermountain Laboratories infrasound microphones

    NASA Astrophysics Data System (ADS)

    Fisher, Aileen

    The term infrasound describes atmospheric sound waves with frequencies below 20 Hz, while acoustics are classified within the audible range of 20 Hz to 20 kHz. Infrasound and acoustic monitoring in the scientific community is hampered by low signal-to-noise ratios and a limited number of studies on regional and short-range noise and source characterization. The JASON Report (2005) suggests the infrasound community focus on more broad-frequency, observational studies within a tactical distance of 10 km. In keeping with that recommendation, this paper presents a study of regional and short-range atmospheric acoustic and infrasonic noise characterization, at a desert site in West Texas, covering a broad frequency range of 0.2 to 100 Hz. To spatially sample the band, a large number of infrasound gauges was needed. A laboratory instrument analysis is presented of the set of low-cost infrasound sensors used in this study, manufactured by Inter-Mountain Laboratories (IML). Analysis includes spectra, transfer functions and coherences to assess the stability and range of the gauges, and complements additional instrument testing by Sandia National Laboratories. The IMLs documented here have been found reliably coherent from 0.1 to 7 Hz without instrument correction. Corrections were built using corresponding time series from the commercially available and more expensive Chaparral infrasound gauge, so that the corrected IML outputs were able to closely mimic the Chaparral output. Arrays of gauges are needed for atmospheric sound signal processing. Our West Texas experiment consisted of a 1.5 km aperture, 23-gauge infrasound/acoustic array of IMLs, with a compact, 12 m diameter grid-array of rented IMLs at the center. To optimize signal recording, signal-to-noise ratio needs to be quantified with respect to both frequency band and coherence length. The higher-frequency grid array consisted of 25 microphones arranged in a five by five pattern with 3 meter spacing, without

  10. 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.

  11. 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.

  12. Droplet actuation by surface acoustic waves: an interplay between acoustic streaming and radiation pressure

    NASA Astrophysics Data System (ADS)

    Brunet, Philippe; Baudoin, Michael; Matar, Olivier Bou; Zoueshtiagh, Farzam

    2010-11-01

    Surface acoustic waves (SAW) are known to be a versatile technique for the actuation of sessile drops. Droplet displacement, internal mixing or drop splitting, are amongst the elementary operations that SAW can achieve, which are useful on lab-on-chip microfluidics benches. On the purpose to understand the underlying physical mechanisms involved during these operations, we study experimentally the droplet dynamics varying different physical parameters. Here in particular, the influence of liquid viscosity and acoustic frequency is investigated: it is indeed predicted that both quantities should play a role in the acoustic-hydrodynamic coupling involved in the dynamics. The key point is to compare the relative magnitude of the attenuation length, i.e. the scale within which the acoustic wave decays in the fluid, and the size of the drop. This relative magnitude governs the relative importance of acoustic streaming and acoustic radiation pressure, which are both involved in the droplet dynamics.

  13. Involvement of pallidotegmental neurons in methamphetamine- and MK-801-induced impairment of prepulse inhibition of the acoustic startle reflex in mice: reversal by GABAB receptor agonist baclofen.

    PubMed

    Arai, Sawako; Takuma, Kazuhiro; Mizoguchi, Hiroyuki; Ibi, Daisuke; Nagai, Taku; Takahashi, Kenji; Kamei, Hiroyuki; Nabeshima, Toshitaka; Yamada, Kiyofumi

    2008-12-01

    We have previously demonstrated that pallidotegmental GABAergic neurons play a crucial role in prepulse inhibition (PPI) of the startle reflex in mice through the activation of GABA(B) receptors in pedunculopontine tegmental neurons. In this study, we investigated whether PPI disruption induced by methamphetamine (METH) or MK-801 is associated with the dysfunction of pallidotegmental neurons. Furthermore, we examined the effects of baclofen, a GABA(B) receptor agonist, on METH- and MK-801-induced PPI impairment. Acute treatment with METH (3 mg/kg, subcutaneouly (s.c.)) and MK-801 (>0.3 mg/kg, s.c.) significantly disrupted PPI, accompanied by the suppression of c-Fos expression in lateral globus pallidus induced by PPI. Furthermore, acute treatment with METH and MK-801 stimulated c-Fos expression in the caudal pontine reticular nucleus (PnC) in mice subjected to the PPT test, although PPI alone had no effect on c-Fos expression. Repeated treatment with 1 mg/kg METH for 7 days, which did not affect PPI acutely, showed similar effects on PPI and c-Fos expression to acute treatment with METH (3 mg/kg). Baclofen dose-dependently ameliorated PPI impairment induced by acute treatment with METH (3 mg/kg) and MK-801 (1 mg/kg), and decreased METH- and MK-801-stimulated c-Fos expression in PnC to the basal level. These results suggest that dysfunction of pallidotegmental neurons is involved in PPI disruption caused by METH and MK-801 in mice. GABA(B) receptor may constitute a putative target in treating neuropsychiatric disorders with sensorimotor gating deficits, such as schizophrenia and METH psychosis.

  14. 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.

  15. 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

  16. Suppression through acoustics

    NASA Astrophysics Data System (ADS)

    Beck, Kevin D.; Short, Kenneth R.; VanMeenen, Kirsten M.; Servatius, Richard J.

    2006-05-01

    This paper reviews research conducted by our laboratory exploring the possible use of acoustical stimuli as a tool for influencing behavior. Over the course of several programs, different types of acoustic stimuli have been evaluated for their effectiveness in disrupting targeting, balance, and high-order cognitive processes in both humans and animals. Escape responses are of particular use in this regard. An escape response serves not only as an objective measure of aversion, but as a potential substitute for ongoing behavior. We have also assessed whether the level of performance changes if the individual does not perform an escape response. In general these studies have both suggested certain types of sounds are more aversive or distracting than others. Although the laboratory development of additional stimuli needs to continue, we are taking the next step by testing some of the more effective stimuli in more applied experimental scenarios including those involving group dynamics.

  17. 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.

  18. 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.}

  19. Medical Acoustics

    NASA Astrophysics Data System (ADS)

    Beach, Kirk W.; Dunmire, Barbrina

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

  20. Sonification of acoustic emission data

    NASA Astrophysics Data System (ADS)

    Raith, Manuel; Große, Christian

    2014-05-01

    While loading different specimens, acoustic emissions appear due to micro crack formation or friction of already existing crack edges. These acoustic emissions can be recorded using suitable ultrasonic transducers and transient recorders. The analysis of acoustic emissions can be used to investigate the mechanical behavior of different specimens under load. Our working group has undertaken several experiments, monitored with acoustic emission techniques. Different materials such as natural stone, concrete, wood, steel, carbon composites and bone were investigated. Also the experimental setup has been varied. Fire-spalling experiments on ultrahigh performance concrete and pullout experiments on bonded anchors have been carried out. Furthermore uniaxial compression tests on natural stone and animal bone had been conducted. The analysis tools include not only the counting of events but the analysis of full waveforms. Powerful localization algorithms and automatic onset picking techniques (based on Akaikes Information Criterion) were established to handle the huge amount of data. Up to several thousand events were recorded during experiments of a few minutes. More sophisticated techniques like moment tensor inversion have been established on this relatively small scale as well. Problems are related to the amount of data but also to signal-to-noise quality, boundary conditions (reflections) sensor characteristics and unknown and changing Greens functions of the media. Some of the acoustic emissions recorded during these experiments had been transferred into audio range. The transformation into the audio range was done using Matlab. It is the aim of the sonification to establish a tool that is on one hand able to help controlling the experiment in-situ and probably adjust the load parameters according to the number and intensity of the acoustic emissions. On the other hand sonification can help to improve the understanding of acoustic emission techniques for training

  1. 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.

  2. ACOUSTICAL IMAGING AND MECHANICAL PROPERTIES OF SOFT ROCK AND MARINE SEDIMENTS

    SciTech Connect

    Thurman E. Scott, Jr.; Younane Abousleiman

    2004-04-01

    The research during this project has concentrated on developing a correlation between rock deformation mechanisms and their acoustic velocity signature. This has included investigating: (1) the acoustic signature of drained and undrained unconsolidated sands, (2) the acoustic emission signature of deforming high porosity rocks (in comparison to their low porosity high strength counterparts), (3) the effects of deformation on anisotropic elastic and poroelastic moduli, and (4) the acoustic tomographic imaging of damage development in rocks. Each of these four areas involve triaxial experimental testing of weak porous rocks or unconsolidated sand and involves measuring acoustic properties. The research is directed at determining the seismic velocity signature of damaged rocks so that 3-D or 4-D seismic imaging can be utilized to image rock damage. These four areas of study are described in the report: (1) Triaxial compression experiments have been conducted on unconsolidated Oil Creek sand at high confining pressures. (2) Initial experiments on measuring the acoustic emission activity from deforming high porosity Danian chalk were accomplished and these indicate that the AE activity was of a very low amplitude. (3) A series of triaxial compression experiments were conducted to investigate the effects of induced stress on the anisotropy developed in dynamic elastic and poroelastic parameters in rocks. (4) Tomographic acoustic imaging was utilized to image the internal damage in a deforming porous limestone sample. Results indicate that the deformation damage in rocks induced during laboratory experimentation can be imaged tomographically in the laboratory. By extension the results also indicate that 4-D seismic imaging of a reservoir may become a powerful tool for imaging reservoir deformation (including imaging compaction and subsidence) and for imaging zones where drilling operation may encounter hazardous shallow water flows.

  3. 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.

  4. The Discourse of Parent Involvement in Special Education: A Critical Analysis Linking Policy Documents to the Experiences of Mothers

    ERIC Educational Resources Information Center

    Lai, Yuan; Vadeboncoeur, Jennifer A.

    2013-01-01

    Parent involvement is acknowledged as a crucial aspect of the education of students with special needs. However, the discourse of parent involvement represents parent involvement in limited ways, thereby controlling how and the extent to which parents can be involved in the education of their children. In this article, critical discourse analysis…

  5. Acoustic Doppler velocimeter-induced acoustic streaming and its implications for measurement

    NASA Astrophysics Data System (ADS)

    Poindexter, C. M.; Rusello, P. J.; Variano, E. A.

    2011-05-01

    The acoustic Doppler velocimeter (ADV) is widely used for the characterization of fluid flow. Secondary flows ("acoustic streaming") generated by the ADV's acoustic pulses may affect the accuracy of measurements in experiments with small velocities. We assessed the impact of acoustic streaming on flow measurement using particle image velocimetry. The probes of two different ADVs were successively mounted in a tank of quiescent water. The probes' ultrasound emitters were aligned with a laser light sheet. Observed flow was primarily in the axial direction, accelerating from the ultrasound emitter and peaking within centimeters of the velocimeter sampling volume before dropping off. We measured the dependence of acoustic streaming velocity on ADV configuration, finding that different settings induce streaming ranging from negligible to more than 2.0 cm s-1. From these results, we describe cases where acoustic streaming affects velocity measurements and also cases where ADVs accurately measure their own acoustic streaming.

  6. Spectrum analysis for introductory musical acoustics

    NASA Astrophysics Data System (ADS)

    Smedley, John E.

    1998-02-01

    A "real time" fast Fourier transform spectrum analyzer facilitates several experiments for an introductory course in musical acoustics. With its rapidly updated display, the time-dependent vibrations of an aluminum bar are easily studied. Using longer time acquisitions and correspondingly higher resolution facilitates the study of string inharmonicities, resonant energy transfer, and sound radiation patterns in guitar acoustics.

  7. Acoustic Emphasis in Four Year Olds

    ERIC Educational Resources Information Center

    Wonnacott, Elizabeth; Watson, Duane G.

    2008-01-01

    Acoustic emphasis may convey a range of subtle discourse distinctions, yet little is known about how this complex ability develops in children. This paper presents a first investigation of the factors which influence the production of acoustic prominence in young children's spontaneous speech. In a production experiment, SVO sentences were…

  8. 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.

  9. Acoustic Sensors for Fission Gas Characterization in MTR Harsh Environment

    NASA Astrophysics Data System (ADS)

    Very, F.; Rosenkrantz, E.; Fourmentel, D.; Destouches, C.; Villard, J. F.; Combette, P.; Ferrandis, J. Y.

    Our group is now working for more than 15 years, in a close partnership with CEA, on the development of acoustic sensors devoted to the characterization of fission gas release for in-pile experiments in Material Testing Reactor. First of all, we will present the main principle of the method and the result of a first succeed experiment called REMORA 3 used to differentiate helium and fission gas released kinetics under transient operating condition [1]. Then we will present our new researches involving thick film transducers produced by screen-printing process in order to propose piezoelectric structures for harsh temperature and irradiation measurements in new MTR reactor.

  10. Shallow Water Acoustic Experiment Analysis

    DTIC Science & Technology

    2009-09-30

    KNORR as it towed a J-15-1 source that emitted four tonals in the 50-250 Hz band, and the deployment locations of two Combustive Sound Source (CSS) events...collected on Array 2 in the 50-250 Hz band. The geoacoustic parameter that is best defined is the sound speed ratio at the water sediment interface... pulse length of the simulated and measured time series agree is an independent confirmation that the attenuation values deduced in Ref. 1 are

  11. Acoustic Seaglider: Philippine Sea Experiment

    DTIC Science & Technology

    2012-09-30

    of 516 km and glider depth of 668 m. Vertical lines indicate alignment with predicted eigenrays . Stars mark the intersection of the predicted...identified eigenrays are indicated. Given large depth-dependent tidal velocities (e.g., as observed with moored ADCPs, J. Colosi, personel

  12. 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.

  13. 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.

  14. 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.

  15. Acoustically enhanced heat transport

    NASA Astrophysics Data System (ADS)

    Ang, Kar M.; Yeo, Leslie Y.; Friend, James R.; Hung, Yew Mun; Tan, Ming K.

    2016-01-01

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ˜ 106 Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξs ˜ 10-9 m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξs ˜ 10-8 m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10-8 m with 106 Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  16. Acoustically enhanced heat transport

    SciTech Connect

    Ang, Kar M.; Hung, Yew Mun; Tan, Ming K.; Yeo, Leslie Y.

    2016-01-15

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10{sup 6} Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξ{sub s} ∼ 10{sup −9} m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξ{sub s} ∼ 10{sup −8} m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10{sup −8} m with 10{sup 6} Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  17. Acoustically enhanced heat transport.

    PubMed

    Ang, Kar M; Yeo, Leslie Y; Friend, James R; Hung, Yew Mun; Tan, Ming K

    2016-01-01

    We investigate the enhancement of heat transfer in the nucleate boiling regime by inducing high frequency acoustic waves (f ∼ 10(6) Hz) on the heated surface. In the experiments, liquid droplets (deionized water) are dispensed directly onto a heated, vibrating substrate. At lower vibration amplitudes (ξs ∼ 10(-9) m), the improved heat transfer is mainly due to the detachment of vapor bubbles from the heated surface and the induced thermal mixing. Upon increasing the vibration amplitude (ξs ∼ 10(-8) m), the heat transfer becomes more substantial due to the rapid bursting of vapor bubbles happening at the liquid-air interface as a consequence of capillary waves travelling in the thin liquid film between the vapor bubble and the air. Further increases then lead to rapid atomization that continues to enhance the heat transfer. An acoustic wave displacement amplitude on the order of 10(-8) m with 10(6) Hz order frequencies is observed to produce an improvement of up to 50% reduction in the surface temperature over the case without acoustic excitation.

  18. Droplet Vaporization In A Levitating Acoustic Field

    NASA Technical Reports Server (NTRS)

    Ruff, G. A.; Liu, S.; Ciobanescu, I.

    2003-01-01

    Combustion experiments using arrays of droplets seek to provide a link between single droplet combustion phenomena and the behavior of complex spray combustion systems. Both single droplet and droplet array studies have been conducted in microgravity to better isolate the droplet interaction phenomena and eliminate or reduce the effects of buoyancy-induced convection. In most experiments involving droplet arrays, the droplets are supported on fibers to keep them stationary and close together before the combustion event. The presence of the fiber, however, disturbs the combustion process by introducing a source of heat transfer and asymmetry into the configuration. As the number of drops in a droplet array increases, supporting the drops on fibers becomes less practical because of the cumulative effect of the fibers on the combustion process. To eliminate the effect of the fiber, several researchers have conducted microgravity experiments using unsupported droplets. Jackson and Avedisian investigated single, unsupported drops while Nomura et al. studied droplet clouds formed by a condensation technique. The overall objective of this research is to extend the study of unsupported drops by investigating the combustion of well-characterized drop clusters in a microgravity environment. Direct experimental observations and measurements of the combustion of droplet clusters would provide unique experimental data for the verification and improvement of spray combustion models. In this work, the formation of drop clusters is precisely controlled using an acoustic levitation system so that dilute, as well as dense clusters can be created and stabilized before combustion in microgravity is begun. While the low-gravity test facility is being completed, tests have been conducted in 1-g to characterize the effect of the acoustic field on the vaporization of single and multiple droplets. This is important because in the combustion experiment, the droplets will be formed and

  19. Expectations and experiences of investigators and parents involved in a clinical trial for Duchenne/Becker muscular dystrophy

    PubMed Central

    Peay, Holly L; Tibben, Aad; Fisher, Tyler; Brenna, Ethan; Biesecker, Barbara B

    2014-01-01

    Background The social context of rare disease research is changing, with increased community engagement around drug development and clinical trials. This engagement may benefit patients and families, but may also lead to heightened trial expectations and therapeutic misconception. Clinical investigators are also susceptible to harboring high expectations. Little is known about parental motivations and expectations for clinical trials for rare pediatric disorders. Purpose We describe the experience of parents and clinical investigators involved in a phase II clinical trial for Duchenne and Becker muscular dystrophy: their expectations, hopes, motivations, and reactions to the termination of the trial. Methods This qualitative study was based on interviews with clinical investigators and parents of sons with DBMD who participated in the phase IIa or IIb ataluren clinical trial in the United States. Interviews were transcribed and coded for thematic analysis. Results Participants were twelve parents of affected boys receiving active drug and nine clinical investigators. High trial expectations of direct benefit were reported by parents and many clinicians. Investigators described monitoring and managing parents’ expectations; several worried about their own involvement in increasing parents’ expectations. Most parents were able to differentiate their expectations from their optimistic hopes for a cure. Parents’ expectations arose from other parents, advocacy organizations, and the sponsor. All parents reported some degree of clinical benefit to their children. Secondary benefits were hopefulness and powerful feelings associated with active efforts to affect the disease course. Parents and clinical investigators reported strong, close relationships that were mutually important. Parents and clinicians felt valued by the sponsor for the majority of the trial. When the trial abruptly stopped, they described loss of engagement, distress, and feeling unprepared for

  20. Molecular change signal-to-noise criteria for interpreting experiments involving exposure of biological systems to weakly interacting electromagnetic fields.

    PubMed

    Vaughan, Timothy E; Weaver, James C

    2005-05-01

    We describe an approach to aiding the design and interpretation of experiments involving biological effects of weakly interacting electromagnetic fields that range from steady (dc) to microwave frequencies. We propose that if known biophysical mechanisms cannot account for an inferred, underlying molecular change signal-to-noise ratio, (S/N)gen, of a observed result, then there are two interpretation choices: (1) there is an unknown biophysical mechanism with stronger coupling between the field exposure and the ongoing biochemical process, or (2) the experiment is responding to something other than the field exposure. Our approach is based on classical detection theory, the recognition that weakly interacting fields cannot break chemical bonds, and the consequence that such fields can only alter rates of ongoing, metabolically driven biochemical reactions, and transport processes. The approach includes both fundamental chemical noise (molecular shot noise) and other sources of competing chemical change, to be compared quantitatively to the field induced change for the basic case that the field alters a single step in a biochemical network. Consistent with pharmacology and toxicology, we estimate the molecular dose (mass associated with field induced molecular change per mass tissue) resulting from illustrative low frequency field exposures for the biophysical mechanism of voltage gated channels. For perspective, we then consider electric field-mediated delivery of small molecules across human skin and into individual cells. Specifically, we consider the examples of iontophoretic and electroporative delivery of fentanyl through skin and electroporative delivery of bleomycin into individual cells. The total delivered amount corresponds to a molecular change signal and the delivery variability corresponds to generalized chemical noise. Viewed broadly, biological effects due to nonionizing fields may include animal navigation, medical applications, and environmental

  1. Protective Behaviour of Citizens to Transport Accidents Involving Hazardous Materials: A Discrete Choice Experiment Applied to Populated Areas nearby Waterways

    PubMed Central

    de Bekker-Grob, Esther W.; Bergstra, Arnold D.; Bliemer, Michiel C. J.; Trijssenaar-Buhre, Inge J. M.; Burdorf, Alex

    2015-01-01

    Background To improve the information for and preparation of citizens at risk to hazardous material transport accidents, a first important step is to determine how different characteristics of hazardous material transport accidents will influence citizens’ protective behaviour. However, quantitative studies investigating citizens’ protective behaviour in case of hazardous material transport accidents are scarce. Methods A discrete choice experiment was conducted among subjects (19–64 years) living in the direct vicinity of a large waterway. Scenarios were described by three transport accident characteristics: odour perception, smoke/vapour perception, and the proportion of people in the environment that were leaving at their own discretion. Subjects were asked to consider each scenario as realistic and to choose the alternative that was most appealing to them: staying, seeking shelter, or escaping. A panel error component model was used to quantify how different transport accident characteristics influenced subjects’ protective behaviour. Results The response was 44% (881/1,994). The predicted probability that a subject would stay ranged from 1% in case of a severe looking accident till 62% in case of a mild looking accident. All three transport accident characteristics proved to influence protective behaviour. Particularly a perception of strong ammonia or mercaptan odours and visible smoke/vapour close to citizens had the strongest positive influence on escaping. In general, ‘escaping’ was more preferred than ‘seeking shelter’, although stated preference heterogeneity among subjects for these protective behaviour options was substantial. Males were less willing to seek shelter than females, whereas elderly people were more willing to escape than younger people. Conclusion Various characteristics of transport accident involving hazardous materials influence subjects’ protective behaviour. The preference heterogeneity shows that information needs

  2. 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.

  3. 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.

  4. 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.

  5. Acoustically Enhanced Electroplating Being Developed

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.

    2002-01-01

    In cooperation with the NASA Glenn Research Center, Alchemitron Corp. is developing the Acoustically Enhanced Electroplating Process (AEEP), a new technique of employing nonlinear ultrasonics to enhance electroplating. The applications range from electroplating full-panel electronic circuit boards to electroplating microelectronics and microelectromechanical systems (MEMS) devices. In a conventional plating process, the surface area to be plated is separated from the nonplated areas by a temporary mask. The mask may take many forms, from a cured liquid coating to a simple tape. Generally, the mask is discarded when the plating is complete, creating a solid waste product that is often an environmental hazard. The labor and materials involved with the layout, fabrication, and tooling of masks is a primary source of recurring and nonrecurring production costs. The objective of this joint effort, therefore, is to reduce or eliminate the need for masks. AEEP improves selective plating processes by using directed beams of high-intensity acoustic waves to create nonlinear effects that alter the fluid dynamic and thermodynamic behavior of the plating process. It relies on two effects: acoustic streaming and acoustic heating. Acoustic streaming is observed when a high-intensity acoustic beam creates a liquid current within the beam. The liquid current can be directed as the beam is directed and, thus, users can move liquid around as desired without using pumps and nozzles. The current of the electroplating electrolyte, therefore, can be directed at distinct target areas where electroplating is desired. The current delivers fresh electrolyte to the target area while flushing away the spent electrolyte. This dramatically increases the plating rate in the target area. In addition, acoustic heating of both the liquid in the beam and the target surface increases the chemical reaction rate, which further increases the plating rate. The combined effects of acoustic streaming and

  6. 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.

  7. Acoustical Properties of Mud Sediments

    DTIC Science & Technology

    2015-09-30

    transmission loss and array response in shallow water over mud sediments and of acoustic detection, localization, and classification of objects buried...classification of objects buried in mud; and improvement of shallow water sonar systems and predictions with mud sediments. RELATED PROJECTS...Characterization Experiment. Collaboration is planned with colleagues at Woods Hole Oceanographic Institution (Jim Lynch, Tim Duda, and Ying-Tsong Lin

  8. The Gelation of Polyvinyl Alcohol with Borax: A Novel Class Participation Experiment Involving the Preparation and Properties of a "Slime."

    ERIC Educational Resources Information Center

    Casassa, E. Z.; And Others

    1986-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment in which students prepare and study the characteristics of a "slime." A list of general, inorganic, and polymer chemistry concepts fostered in the experiment is included. (JN)

  9. Acoustic metamaterials for sound mitigation

    NASA Astrophysics Data System (ADS)

    Assouar, Badreddine; Oudich, Mourad; Zhou, Xiaoming

    2016-05-01

    We provide theoretical and numerical analyses of the behavior of a plate-type acoustic metamaterial considered in an air-borne sound environment in view of sound mitigation application. Two configurations of plate are studied, a spring-mass one and a pillar system-based one. The acoustic performances of the considered systems are investigated with different approaches and show that a high sound transmission loss (STL) up to 82 dB is reached with a metamaterial plate with a thickness of 0.5 mm. The physical understanding of the acoustic behavior of the metamaterial partition is discussed based on both air-borne and structure-borne approaches. Confrontation between the STL, the band structure, the displacement fields and the effective mass density of the plate metamaterial is made to have a complete physical understanding of the different mechanisms involved.

  10. Involvement in Campus Activities and the Retention of First-Year College Students. The First-Year Experience Monograph Series.

    ERIC Educational Resources Information Center

    Skipper, Tracy L., Ed.; Argo, Roxanne, Ed.

    The chapters of this monograph offer insights into educationally purposeful out-of-class activities and the impact they have on the student experience. It also provides future directions for the campus activities field and identifies ways to improve the educational experience of first-year students to enhance their scholarly experience and to…

  11. 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.

  12. Electro-acoustic stimulation. Acoustic and electric pitch comparisons.

    PubMed

    McDermott, Hugh; Sucher, Catherine; Simpson, Andrea

    2009-01-01

    For simultaneous acoustic and electric stimulation to be perceived as complementary, it may be beneficial for hearing aids and cochlear implants (CI) to be adjusted to provide compatible pitch sensations. To this end, estimates of the pitch perceived for a set of acoustic and electric stimuli were obtained from 14 CI users who had usable low-frequency hearing, either in the non-implanted ear or in both ears. The subjects assigned numerical pitch estimates to each of 5 acoustic pure tones and 5 single-electrode electric pulse trains. On average, the acoustic frequency that corresponded in pitch to stimulation on the most apical electrode was approximately 480 Hz. This was about 1 octave lower than the frequency expected from Greenwood's frequency-place function applied to estimates of the electrode insertion angle based on X-ray images. Furthermore, evidence was found suggesting that pitch decreased with increasing duration of CI use. Pitch estimates from 5 subjects who completed the experiment before experiencing any other sounds through their CI were generally close to the values expected from a recently published frequency map for the cochlear spiral ganglion. Taken together, these findings suggest that some perceptual adaptation may occur that would compensate in part for the apparent mismatch between the intracochlear position of the electrodes and the acoustic frequencies assigned to them in the sound processor.

  13. Developments and field tests of low-frequency portable acoustic transducers for a mobile exploration and time lapse experiment of a sea-bottom reservoir

    NASA Astrophysics Data System (ADS)

    Tsuruga, K.; Kasahara, J.; Hasada, Y.; Kondo, H.

    2013-12-01

    Depth, scale and resolutions of geophysical explorations for mineral resources are controlled by transmitted seismic energy and wavelength (frequency range). Most explorations in marine have been conducted by survey ship system with arrayed acoustic sources whose dominant frequency range is about 10 to 500 Hz. On the other hand, for shallow parts of sea bottom structure survey, some sub-bottom profilers with frequency range around 3.5kHz are used. To monitor a time lapse of a sea bottom reservoir such as an oil, gas, or methane hydrate reservoir as well as to exploit a mobile survey near a sea bottom by AUVs, it is necessary to use a broadband portable acoustic transducer with a dominant frequency range of 500 Hz to 5 kHz. We have been developing several types of portable acoustic transducers and a transmitting and recording system which is accurately controlled by a GPS clock (Tsuruga et al., 2012). In this pater, we report the new broadband acoustic portable transducers which have larger power than the original cylindrical acoustic transducers in a low frequency range (<5 kHz), partly funded by JOGMEC, and show the preliminary results of field tests at the shallow sea bottom around 32 m deep by means of the transducers and hydrophone receivers array. Each transducer repeatedly transmitted Chirp signals with a unit period of 500 msec in two frequency ranges of 0.5k-4.5kHz and 4k-16kHz . We stacked 500-ms data by 28 times to obtain a transfer function of each source-receiver pair in the time and frequency domains. The preliminary results suggest as the follows: (i) it is successful to broaden the frequency bandwidth (i.e., 2k-10kHz) by extending a geometrical resonance length of a cylindrical acoustic transducers, and (ii) the observation at the sea bottom with accurately controlled timing systems of transmitter and data-logger is very useful to identify the stable and/or unstable seismic phases, that is, waves propagating in a underground and/or in a sea water as

  14. The Long Term Effects of Undergraduate Student Involvement Experiences on Selected Outcome Measures. AIR 1995 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Fischer, Norman M.

    The long-term effects of undergraduate involvement on advanced degree attainment and career choice were studied. The longitudinal study involved 299 freshmen who entered college between 1973 and 1976 and participated in the institutional research program's followup questionnaire 17-20 years later. Astin's Input-Environment Outcomes model and…

  15. Studies of Ion Acoustic Decay

    SciTech Connect

    Drake, R.P.; Bauer, B.S.; Baker, K.L. |

    1994-03-07

    In this project, we advanced knowledge of Ion Acoustic Decay on several fronts. In this project, we have developed and demonstrated the capability to perform experimental and theoretical studies of the Ion Acoustic Decay Instability. We have at the same time demonstrated an improved capability to do multichannel spectroscopy and Thomson scattering. We made the first observations of the time-resolved second harmonic emission at several angles simultaneously, and the first observations of the emission both parallel and perpendicular to the electric field of the laser light. We used Thomson scattering to make the first observations of the plasma waves driven by acoustic decay in a warm plasma with long density scale lengths. We also advanced both the linear and the nonlinear theory of this instability. We are thus prepared to perform experiments to address this mechanism as needed for applications.

  16. 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.

  17. Planar and nonplanar ion acoustic shock waves in relativistic degenerate astrophysical electron-positron-ion plasmas

    SciTech Connect

    Ata-ur-Rahman,; Qamar, A.; Ali, S.; Mirza, Arshad M.

    2013-04-15

    We have studied the propagation of ion acoustic shock waves involving planar and non-planar geometries in an unmagnetized plasma, whose constituents are non-degenerate ultra-cold ions, relativistically degenerate electrons, and positrons. By using the reductive perturbation technique, Korteweg-deVries Burger and modified Korteweg-deVries Burger equations are derived. It is shown that only compressive shock waves can propagate in such a plasma system. The effects of geometry, the ion kinematic viscosity, and the positron concentration are examined on the ion acoustic shock potential and electric field profiles. It is found that the properties of ion acoustic shock waves in a non-planar geometry significantly differ from those in planar geometry. The present study has relevance to the dense plasmas, produced in laboratory (e.g., super-intense laser-dense matter experiments) and in dense astrophysical objects.

  18. Plasticity in developing brain: active auditory exposure impacts prelinguistic acoustic mapping.

    PubMed

    Benasich, April A; Choudhury, Naseem A; Realpe-Bonilla, Teresa; Roesler, Cynthia P

    2014-10-01

    A major task across infancy is the creation and tuning of the acoustic maps that allow efficient native language processing. This process crucially depends on ongoing neural plasticity and keen sensitivity to environmental cues. Development of sensory mapping has been widely studied in animal models, demonstrating that cortical representations of the sensory environment are continuously modified by experience. One critical period for optimizing human language mapping is early in the first year; however, the neural processes involved and the influence of passive compared with active experience are as yet incompletely understood. Here we demonstrate that, while both active and passive acoustic experience from 4 to 7 months of age, using temporally modulated nonspeech stimuli, impacts acoustic mapping, active experience confers a significant advantage. Using event-related potentials (ERPs), we show that active experience increases perceptual vigilance/attention to environmental acoustic stimuli (e.g., larger and faster P2 peaks) when compared with passive experience or maturation alone. Faster latencies are also seen for the change discrimination peak (N2*) that has been shown to be a robust infant predictor of later language through age 4 years. Sharpening is evident for both trained and untrained stimuli over and above that seen for maturation alone. Effects were also seen on ERP morphology for the active experience group with development of more complex waveforms more often seen in typically developing 12- to 24-month-old children. The promise of selectively "fine-tuning" acoustic mapping as it emerges has far-reaching implications for the amelioration and/or prevention of developmental language disorders.

  19. 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.

  20. 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.

  1. 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 ...

  2. To do, to have, or to share? Valuing experiences over material possessions depends on the involvement of others.

    PubMed

    Caprariello, Peter A; Reis, Harry T

    2013-02-01

    Recent evidence indicates that spending discretionary money with the intention of acquiring life experiences-events that one lives through-makes people happier than spending money with the intention of acquiring material possessions-tangible objects that one obtains and possesses. We propose and show that experiences are more likely to be shared with others, whereas material possessions are more prone to solitary use and that this distinction may account for their differential effects on happiness. In 4 studies, we present evidence demonstrating that the inclusion of others is a key dimension of how people derive happiness from discretionary spending. These studies showed that when the social-solitary and experiential-material dimensions were considered simultaneously, social discretionary spending was favored over solitary discretionary spending, whereas experiences showed no happiness-producing advantage relative to possessions. Furthermore, whereas spending money on socially shared experiences was valued more than spending money on either experiences enacted alone or material possessions, solitary experiences were no more valued than material possessions. Together, these results extend and clarify the basic findings of prior research and add to growing evidence that the social context of experiences is critical for their effects on happiness.

  3. The Suppression of Dominant Acoustic Frequencies in MRI

    NASA Astrophysics Data System (ADS)

    Shou, Xingxian; Brown, Robert

    2011-03-01

    Patient discomfort and brain imaging distortion are serious MRI acoustic noise problems arising from the rapid switching on and off of gradient coils in the presence of the strong Larmor magnetic field. A study is made of dominant frequencies in the acoustic noise spectrum and, motivated by both spring and string ideas, we propose the cancellation of selected frequencies by appropriate gradient pulse sequence design. From both simulations and experiments, vibrations resulting from an impulsive force associated with a ramping up of a gradient pulse are shown to be cancelled upon the application of another impulsive force coming from the appropriately timed ramping down of that pulse. A method for the suppression of multiple-frequency contributions involving a series of gradient pulses with variable timings is developed and confirmed by experiment. Whether we refer to reduction in terms of dB (about 30-40 dB per peak), or to the verdict of a listener, the conclusion is that a marked reduction in sound can be achieved when at least three of the dominant frequency peaks are suppressed. A variety of pulse profiles and timing combinations can be used to attenuate important contributions to the acoustic spectrum. Supported by the Ohio Third Frontier Program.

  4. 3D Simulation as a Learning Environment for Acquiring the Skill of Self-Management: An Experience Involving Spanish University Students of Education

    ERIC Educational Resources Information Center

    Cela-Ranilla, Jose María; Esteve-Gonzalez, Vanessa; Esteve-Mon, Francesc; Gisbert-Cervera, Merce

    2014-01-01

    In this study we analyze how 57 Spanish university students of Education developed a learning process in a virtual world by conducting activities that involved the skill of self-management. The learning experience comprised a serious game designed in a 3D simulation environment. Descriptive statistics and non-parametric tests were used in the…

  5. Acoustic Probe for Solid-Gas-Liquid Suspension

    SciTech Connect

    Tavlarides, L.L.; Sangani, Ashok

    2003-09-14

    The primary objective of the research project during the first funding period was to develop an acoustic probe to measure volume percent solids in solid-liquid slurries in the presence of small amounts of gas bubbles. This problem was addressed because of the great need for a non-invasive, accurate and reliable method for solids monitoring in liquid slurries in the presence of radiolytically generated gases throughout the DOE complex. These measurements are necessary during mobilization of salts and sediments in tanks, transport of these slurries in transfer lines to processing facilities across a site, and, in some instances, during high level waste processing. Although acoustic probes have been commonly used for monitoring flows in single-phase fluids (McLeod, 1967), their application to monitor two-phase mixtures has not yet fully realized its potential. A number of investigators in recent years have therefore been involved in developing probes for measuring the volume fractions in liquid solid suspensions (Atkinson and Kytomaa, 1993; Greenwood et al., 1993; Martin et al., 1995) and in liquid-liquid suspensions (Bonnet and Tavlarides, 1987; Tavlarides and Bonnet, 1988, Yi and Tavlarides, 1990; Tsouris and Tavlarides, 1993, Tsouris et al., 1995). In particular, Atkinson and Kytomaa (1993) showed that the acoustic technique can be used to determine both the velocity and the volume fraction of solids while Martin et al. (1995) and Spelt et al. (1999) showed that the acoustic probe can also be used to obtain information on the size distribution of the particles. In a recent testing of in-line slurry monitors with radioactive slurries suspended with Pulsair Mixers (Hylton & Bayne, 1999), an acoustic probe did not compare well with other instruments most probably due to presence of entrained gases and improper acoustic frequency range of interrogation. The work of the investigators cited has established the potential of the acoustic probe for characterizing

  6. Improved Calibration Of Acoustic Plethysmographic Sensors

    NASA Technical Reports Server (NTRS)

    Zuckerwar, Allan J.; Davis, David C.

    1993-01-01

    Improved method of calibration of acoustic plethysmographic sensors involves acoustic-impedance test conditions like those encountered in use. Clamped aluminum tube holds source of sound (hydrophone) inside balloon. Test and reference sensors attached to outside of balloon. Sensors used to measure blood flow, blood pressure, heart rate, breathing sounds, and other vital signs from surfaces of human bodies. Attached to torsos or limbs by straps or adhesives.

  7. 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 ...

  8. 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.

  9. 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 ...

  10. Parental Involvement and the Developmental Stages of Writing: Knowledge and Skills to Assist Children and Parent Perceptions on Their Experience

    ERIC Educational Resources Information Center

    Fernandez-Kaltenbach, Elena

    2009-01-01

    A kindergarten parent workshop series on the developmental stages of writing was created and assessed. The intended outcome was to empower parents with writing knowledge and writing skills so that they could apply this knowledge and skills at home with their child. The researcher developed the workshops from parent involvement research,…

  11. Children's Well-Being and Involvement in Physically Active Outdoors Play in a Norwegian Kindergarten: Playful Sharing of Physical Experiences

    ERIC Educational Resources Information Center

    Bjørgen, Kathrine

    2015-01-01

    This qualitative study explores the conditions of children's level of well-being and their involvement in physically active play during kindergarten outdoors time. Observations of three to five year olds from one kindergarten in central Norway were conducted. The researcher followed the children around the kindergarten's outdoors playground and…

  12. Mexican American Parents' Involvement in Adolescents' Peer Relationships: Exploring the Role of Culture and Adolescents' Peer Experiences

    ERIC Educational Resources Information Center

    Updegraff, Kimberly A.; Kim, Ji-Yeon; Killoren, Sarah E.; Thayer, Shawna M.

    2010-01-01

    This study examined the nature and correlates of Mexican American mothers' and fathers' involvement in adolescents' peer relationships along 4 dimensions: support, restriction, knowledge, and time spent with adolescents and peers. Mexican American adolescents and their parents in 220 families described their family relationships, cultural…

  13. Rural Schooling in Georgia: The Experiences of a Minority Community Service Organization Involved in Local School Decision-Making Activities

    ERIC Educational Resources Information Center

    Lowe, Cynthia Louise Altman

    2010-01-01

    This dissertation study was a descriptive case study of a minority community service organization whose members were actively involved in local school decision-making and activities in a rural Northeast Georgia community. Rural schools face unique challenges in light of current educational trends. To address the challenges, rural schools must…

  14. Family Physician Involvement in Cancer Care Follow-up: The Experience of a Cohort of Patients With Lung Cancer

    PubMed Central

    Aubin, Michèle; Vézina, Lucie; Verreault, René; Fillion, Lise; Hudon, Éveline; Lehmann, François; Leduc, Yvan; Bergeron, Rénald; Reinharz, Daniel; Morin, Diane

    2010-01-01

    PURPOSE There has been little research describing the involvement of family physicians in the follow-up of patients with cancer, especially during the primary treatment phase. We undertook a prospective longitudinal study of patients with lung cancer to assess their family physician’s involvement in their follow-up at the different phases of cancer. METHODS In 5 hospitals in the province of Quebec, Canada, patients with a recent diagnosis of lung cancer were surveyed every 3 to 6 months, whether they had metastasis or not, for a maximum of 18 months, to assess aspects of their family physician’s involvement in cancer care. RESULTS Of the 395 participating patients, 92% had a regular family physician but only 60% had been referred to a specialist by him/her or a colleague for the diagnosis of their lung cancer. A majority of patients identified the oncology team or oncologists as mainly responsible for their cancer care throughout their cancer journey, except at the advanced phase, where a majority attributed this role to their family physician. At baseline, only 16% of patients perceived a shared care pattern between their family physician and oncologists, but this proportion increased with cancer progression. Most patients would have liked their family physician to be more involved in all aspects of cancer care. CONCLUSIONS Although patients perceive that the oncology team is the main party responsible for the follow-up of their lung cancer, they also wish their family physicians to be involved. Better communication and collaboration between family physicians and the oncology team are needed to facilitate shared care in cancer follow-up. PMID:21060123

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Virtual acoustics for music practice rooms

    NASA Astrophysics Data System (ADS)

    Freiheit, Ron

    2003-04-01

    The use of virtual acoustics has provided a new level of practice experience for the musician. By integrating the sound isolation of music practice rooms with the signal processing of an active acoustic system (with time variant-gain before feedback) musicians can now benefit from the experience of practicing in multiple acoustic environments. Musicians select from various acoustics environments from a typical small practice room to that of a large space such as a sports arena. The variability of the acoustic environment allows the musician to hear clearly their intonation and articulation, which may be difficult to discern in a small practice room. To effectively communicate the various acoustics environments, the musicians must be immersed in the sound field of the active acoustics without being able to discern source locations of the speakers. The system must also be able to support the dynamic range of the musicians without presenting artifacts of its own such as system noise or audible distortion. This paper deals with the design constraints needed to meet these requirements as well the antidotal responses from musicians who have used these environments for practice.

  20. 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.

  1. 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).

  2. APL - North Pacific Acoustic Laboratory

    DTIC Science & Technology

    2011-09-01

    ambient noise Figure 4. Number of ships in the world fleet. 5 Ten years ago, we were working with Lori Mazzucca , a graduate student in the...and 2000 correspond very well with those from Mazzucca (which involved two sources.) This gives us confidence that these IMO values were derived...Acoustical Society of America, 129(2), pp 642-651, 2011. [4] L. Mazzucca . Potential Effects of Low Frequency Sound (LFS) from Commercial Vessels

  3. Measuring the acoustic response of Helmholtz resonators

    NASA Astrophysics Data System (ADS)

    Monteiro, Martín; Marti, Arturo C.; Vogt, Patrik; Kasper, Lutz; Quarthal, Dominik

    2015-04-01

    Many experiments have been proposed to investigate acoustic phenomena in college and early undergraduate levels, in particular the speed of sound,1-9 by means of different methods, such as time of flight, transit time, or resonance in tubes. In this paper we propose to measure the acoustic response curves of a glass beaker filled with different gases, used as an acoustic resonator. We show that these curves expose many interesting peaks and features, one of which matches the resonance peak predicted for a Helmholtz resonator fairly well, and gives a decent estimate for the speed of sound in some cases. The measures are obtained thanks to the capabilities of smartphones.

  4. Experience of emotional stress and resilience in street-involved youth: the need for early mental health intervention.

    PubMed

    McCay, Elizabeth

    2011-01-01

    Mental illness left untreated in adolescence and young adulthood can readily become a chronic illness in adulthood, seriously hampering the capacity of individuals to become healthy contributing members of society. Mental health challenges are of paramount importance to the health and well-being of Canadian adolescents and young adults, with 18% of Canadian youth, ages 15-24, reporting a mental illness (Leitch 2007). However, it is unlikely that this statistic accounts for those invisible youth (Rachlis et al. 2009) who are disconnected from families and caregivers, bereft of stable housing and familial support - in other words, youth who are street-involved. Mental health risk is amplified in street-involved youth and, as such, must be recognized as a priority for policy development that commits to accessible mental health programming, in order to realize the potential of these vulnerable youth.

  5. Role of Craniofacial Resection for Malignant Tumors Involving the Anterior Skull Base: Surgical Experience in a Single Institution

    PubMed Central

    Kim, You-Sub; Kim, Gun-Woo; Lim, Sang Chul; Lee, Kyung-Hwa; Jang, Woo-Youl; Jung, Tae-Young; Kim, In-Young; Jung, Shin

    2015-01-01

    Background Craniofacial resection (CFR) has been regarded as a standard treatment for various tumors involving the anterior skull base. The purpose of this study was to evaluate the results of CFR for the patients with anterior skull base malignancies in our hospital. Methods We retrospectively analyzed 17 patients with anterior skull base malignancies treated with CFR between 2001 and 2012. Mean follow-up duration was 41 months (range, 2-103 months). Results Intracranial involvement was found in 11 patients (65%) and orbital extension in 6 patients (35%). Classical bifrontal craniotomy was combined with endoscopic endonasal approach in 14 patients and external approach in 3 patients. Vascularized flap was used for reconstruction of the anterior fossa floor in 16 patients (94%). The most common pathological type was squamous cell carcinoma (6 patients). Gross total resection was achieved in all cases. Postoperative complications developed in 4 patients (24%) and included local wound problem and brain abscess. One patient with liver cirrhosis died from unexpected varix bleeding after the operation. Although postoperative treatment, such as radiotherapy or chemotherapy, was performed in 14 patients, local recurrence was seen in 6 patients. The mean overall survival time after the operation was 69.0 months (95% confidence interval: 47.5-90.5 months) with a 1-, 2-, and 5-year survival rate of 82.3%, 76.5%, and 64.7%, respectively. Postoperative radiotherapy was found to be the powerful prognostic factor for favorable survival. Conclusion Considering the higher local control rate and acceptable complication or mortality rate, CFR with adjuvant radiotherapy is a gold standard treatment option for malignant tumors involving anterior skull base, especially with extensive intracranial involvement. PMID:26605262

  6. Subjective Experiences in Activity Involvement and Perceptions of Growth in a Sample of First-Year Female University Students

    ERIC Educational Resources Information Center

    Busseri, Michael A.; Rose-Krasnor, Linda

    2008-01-01

    We examined subjective experiences in activities and perceptions of growth in a sample of first-year female university students (N = 196; age range = 17 to 19 years old, M = 18.48, SD = 0.53; the most common ethnic affiliations were British Isles, 51% of respondents, Canadian, 34%, French, 14%, and German, 8%). Students described 4 activities,…

  7. The Student Guide for Career Analysis. Community Involvement/Career Education: An Experience-based Social Studies Program, Volume I.

    ERIC Educational Resources Information Center

    Kyle, James; And Others

    The guide provides multiple experience-based activities for use by secondary social studies students as they examine occupational possibilities in their communities. The purposes of the materials are to help students evaluate themselves and their value systems, examine occupations, and become aware of the changing philosophy and value of work in…

  8. Teachers' Perspective towards Their Involvement in Selection and Organization of Learning Experiences and Implementation of Secondary School Curriculum in Kenya

    ERIC Educational Resources Information Center

    Kobiah, Lydia Kanake

    2016-01-01

    Teacher empowerment has been the subject of considerable educational research in recent years, but the capacity of teachers in curriculum development especially in selection and organization of learning experiences has received limited empirical attention. The purpose of this study was to establish teachers' perspective towards their involvement…

  9. Blind deconvolution applied to acoustical systems identification with supporting experimental results

    NASA Astrophysics Data System (ADS)

    Roan, Michael J.; Gramann, Mark R.; Erling, Josh G.; Sibul, Leon H.

    2003-10-01

    Many acoustical applications require the analysis of a signal that is corrupted by an unknown filtering function. Examples arise in the areas of noise or vibration control, room acoustics, structural vibration analysis, and speech processing. Here, the observed signal can be modeled as the convolution of the desired signal with an unknown system impulse response. Blind deconvolution refers to the process of learning the inverse of this unknown impulse response and applying it to the observed signal to remove the filtering effects. Unlike classical deconvolution, which requires prior knowledge of the impulse response, blind deconvolution requires only reasonable prior estimates of the input signal's statistics. The significant contribution of this work lies in experimental verification of a blind deconvolution algorithm in the context of acoustical system identification. Previous experimental work concerning blind deconvolution in acoustics has been minimal, as previous literature concerning blind deconvolution uses computer simulated data. This paper examines experiments involving three classical acoustic systems: driven pipe, driven pipe with open side branch, and driven pipe with Helmholtz resonator side branch. Experimental results confirm that the deconvolution algorithm learns these systems' inverse impulse responses, and that application of these learned inverses removes the effects of the filters.

  10. How Listeners Weight Acoustic Cues to Intonational Phrase Boundaries

    PubMed Central

    Yang, Xiaohong; Shen, Xiangrong; Li, Weijun; Yang, Yufang

    2014-01-01

    The presence of an intonational phrase boundary is often marked by three major acoustic cues: pause, final lengthening, and pitch reset. The present study investigates how these three acoustic cues are weighted in the perception of intonational phrase boundaries in two experiments. Sentences that contained two intonational phrases with a critical boundary between them were used as the experimental stimuli. The roles of the three acoustic cues at the critical boundary were manipulated in five conditions. The first condition featured none of the acoustic cues. The following three conditions featured only one cue each: pause, final lengthening, and pitch reset, respectively. The fifth condition featured both pause duration and pre-final lengthening. A baseline condition was also included in which all three acoustic cues were preserved intact. Listeners were asked to detect the presence of the critical boundaries in Experiment 1 and judge the strength of the critical boundaries in Experiment 2. The results of both experiments showed that listeners used all three acoustic cues in the perception of prosodic boundaries. More importantly, these acoustic cues were weighted differently across the two experiments: Pause was a more powerful perceptual cue than both final lengthening and pitch reset, with the latter two cues perceptually equivalent; the effect of pause and the effects of the other two acoustic cues were not additive. These results suggest that the weighting of acoustic cues contributes significantly to the perceptual differences of intonational phrase boundary. PMID:25019156

  11. Acoustic emission from composite materials. [nondestructive tests

    NASA Technical Reports Server (NTRS)

    Visconti, I. C.; Teti, R.

    1979-01-01

    The two basic areas where the acoustic emission (AE) technique can be applied are materials research and the evaluation of structural reliability. This experimental method leads to a better understanding of fracture mechanisms and is an NDT technique particularly well suited for the study of propagating cracks. Experiments are described in which acoustic emissions were unambiguously correlated with microstructural fracture mechanisms. The advantages and limitations of the AE technique are noted.

  12. Computational and experimental techniques for coupled acoustic/structure interactions.

    SciTech Connect

    Sumali, Anton Hartono; Pierson, Kendall Hugh; Walsh, Timothy Francis; Dohner, Jeffrey Lynn; Reese, Garth M.; Day, David Minot

    2004-01-01

    This report documents the results obtained during a one-year Laboratory Directed Research and Development (LDRD) initiative aimed at investigating coupled structural acoustic interactions by means of algorithm development and experiment. Finite element acoustic formulations have been developed based on fluid velocity potential and fluid displacement. Domain decomposition and diagonal scaling preconditioners were investigated for parallel implementation. A formulation that includes fluid viscosity and that can simulate both pressure and shear waves in fluid was developed. An acoustic wave tube was built, tested, and shown to be an effective means of testing acoustic loading on simple test structures. The tube is capable of creating a semi-infinite acoustic field due to nonreflecting acoustic termination at one end. In addition, a micro-torsional disk was created and tested for the purposes of investigating acoustic shear wave damping in microstructures, and the slip boundary conditions that occur along the wet interface when the Knudsen number becomes sufficiently large.

  13. 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.

  14. Male involvement during pregnancy and childbirth: men’s perceptions, practices and experiences during the care for women who developed childbirth complications in Mulago Hospital, Uganda

    PubMed Central

    2014-01-01

    Background Development of appropriate interventions to increase male involvement in pregnancy and childbirth is vital to strategies for improving health outcomes of women with obstetric complications. The objective was to gain a deeper understanding of their experiences of male involvement in their partners’ healthcare during pregnancy and childbirth. The findings might inform interventions for increasing men’s involvement in reproductive health issues. Methods We conducted 16 in-depth interviews with men who came to the hospital to attend to their spouses/partners admitted to Mulago National Referral Hospital. All the spouses/partners had developed severe obstetric complications and were admitted in the high dependency unit. We sought to obtain detailed descriptions of men’s experiences, their perception of an ideal “father” and the challenges in achieving this ideal status. We also assessed perceived strategies for increasing male participation in their partners’ healthcare during pregnancy and childbirth. Data was analyzed by content analysis. Results The identified themes were: Men have different descriptions of their relationships; responsibility was an obligation; ideal fathers provide support to mothers during childbirth; the health system limits male involvement in childbirth; men have no clear roles during childbirth, and exclusion and alienation in the hospital environment. The men described qualities of the ideal father as one who was available, easily reached, accessible and considerate. Most men were willing to learn about their expected roles during childbirth and were eager to support their partners/wives/spouses during this time. However, they identified personal, relationship, family and community factors as barriers to their involvement. They found the health system unwelcoming, intimidating and unsupportive. Suggestions to improve men’s involvement include creating more awareness for fathers, male-targeted antenatal education and

  15. 78 FR 19652 - Takes of Marine Mammals Incidental to Specified Activities; Office of Naval Research Acoustic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-02

    ... Specified Activities; Office of Naval Research Acoustic Technology Experiments in the Western North Pacific... Acoustic Technology Experiments (ATE) in the western North Pacific Ocean. The Navy's activities are... underwater active acoustic sources are likely to result in the take of marine mammals. Take, by Level...

  16. Involvement of activated leukocytes in the regulation of plasma levels of acute phase proteins in microgravity simulation experiments

    NASA Astrophysics Data System (ADS)

    Larina, Olga; Bekker, Anna; Turin-Kuzmin, Alexey

    2016-07-01

    Earth-based studies of microgravity effects showed the induction of the mechanisms of acute phase reaction (APR). APR comprises the transition of stress-sensitive protein kinases of macrophages and other responsive cells into the active state and the phosphorylation of transcription factors which in turn stimulate the production of acute-phase reaction cytokines. Leukocyte activation is accompanied by the acceleration of the formation of oxygen radicals which can serve a functional indice of leukocyte cell state. The series of events at acute phase response result in selective changes in the synthesis of a number of secretory blood proteins (acute phase proteins, APPs) in liver cells thus contributing the recovery of homeostasis state in the organism. Earlier experiment with head-down tilt showed the increase in plasma concentrations of two cytokine mediators of acute phase response, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) being the outcome of the activation of producer cells, foremost, leukocytes. In experiment with 4-day dry immersion chemiluminescent (ChL) reply of the whole blood samples to a test stimulus were studied along with the measurements of plasma levels of APPs, namely, alpha1-antitrypsin (alpha1-AT), alpha1-acid glycoprotein (alpha1-AGP), alpha2-macroglobulin (alpha2-M), ceruloplasmin (Cer), haptoglobin (Hp), C3-complement component (C3), C-reactive protein (CRP). Eight individuals aged 21.2 ± 3.2 years were the test subjects in the investigation. Protein studies showed a noticeable increase in the mean plasma levels of all APPs measured in experiment thus producing the evidence of the activation of acute phase response mechanisms while individual patterns revealed variability during the immersion period. The overall trends were similar to these in the previous immersion series. The augment in the strength of signal in stimulated light emission tests was higher after 1- and 2-day of immersion exposure than before the

  17. Longitudinal bulk acoustic mass sensor

    SciTech Connect

    Hales, J. H.; Teva, J.; Boisen, A.; Davis, Z. J.

    2009-07-20

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10{sup -15} g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.

  18. Longitudinal bulk acoustic mass sensor

    NASA Astrophysics Data System (ADS)

    Hales, J. H.; Teva, J.; Boisen, A.; Davis, Z. J.

    2009-07-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10-15 g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.

  19. Decoding Group Vocalizations: The Acoustic Energy Distribution of Chorus Howls Is Useful to Determine Wolf Reproduction

    PubMed Central

    López-Bao, José Vicente; Llaneza, Luis; Fernández, Carlos; Font, Enrique

    2016-01-01

    Population monitoring is crucial for wildlife management and conservation. In the last few decades, wildlife researchers have increasingly applied bioacoustics tools to obtain information on several essential ecological parameters, such as distribution and abundance. One such application involves wolves (Canis lupus). These canids respond to simulated howls by emitting group vocalizations known as chorus howls. These responses to simulated howls reveal the presence of wolf litters during the breeding period and are therefore often used to determine the status of wolf populations. However, the acoustic structure of chorus howls is complex and discriminating the presence of pups in a chorus is sometimes difficult, even for experienced observers. In this study, we evaluate the usefulness of analyses of the acoustic energy distribution in chorus howls to identify the presence of pups in a chorus. We analysed 110 Iberian wolf chorus howls with known pack composition and found that the acoustic energy distribution is concentrated at higher frequencies when there are pups vocalizing. We built predictive models using acoustic energy distribution features to determine the presence of pups in a chorus, concluding that the acoustic energy distribution in chorus howls can be used to determine the presence of wolf pups in a pack. The method we outline here is objective, accurate, easily implemented, and independent of the observer's experience. These advantages are especially relevant in the case of broad scale surveys or when many observers are involved. Furthermore, the analysis of the acoustic energy distribution can be implemented for monitoring other social canids that emit chorus howls such as jackals or coyotes, provides an easy way to obtain information on ecological parameters such as reproductive success, and could be useful to study other group vocalizations. PMID:27144887

  20. Decoding Group Vocalizations: The Acoustic Energy Distribution of Chorus Howls Is Useful to Determine Wolf Reproduction.

    PubMed

    Palacios, Vicente; López-Bao, José Vicente; Llaneza, Luis; Fernández, Carlos; Font, Enrique

    2016-01-01

    Population monitoring is crucial for wildlife management and conservation. In the last few decades, wildlife researchers have increasingly applied bioacoustics tools to obtain information on several essential ecological parameters, such as distribution and abundance. One such application involves wolves (Canis lupus). These canids respond to simulated howls by emitting group vocalizations known as chorus howls. These responses to simulated howls reveal the presence of wolf litters during the breeding period and are therefore often used to determine the status of wolf populations. However, the acoustic structure of chorus howls is complex and discriminating the presence of pups in a chorus is sometimes difficult, even for experienced observers. In this study, we evaluate the usefulness of analyses of the acoustic energy distribution in chorus howls to identify the presence of pups in a chorus. We analysed 110 Iberian wolf chorus howls with known pack composition and found that the acoustic energy distribution is concentrated at higher frequencies when there are pups vocalizing. We built predictive models using acoustic energy distribution features to determine the presence of pups in a chorus, concluding that the acoustic energy distribution in chorus howls can be used to determine the presence of wolf pups in a pack. The method we outline here is objective, accurate, easily implemented, and independent of the observer's experience. These advantages are especially relevant in the case of broad scale surveys or when many observers are involved. Furthermore, the analysis of the acoustic energy distribution can be implemented for monitoring other social canids that emit chorus howls such as jackals or coyotes, provides an easy way to obtain information on ecological parameters such as reproductive success, and could be useful to study other group vocalizations.

  1. Feedback of research findings for vaccine trials: experiences from two malaria vaccine trials involving healthy children on the Kenyan Coast.

    PubMed

    Gikonyo, Caroline; Kamuya, Dorcas; Mbete, Bibi; Njuguna, Patricia; Olotu, Ally; Bejon, Philip; Marsh, Vicki; Molyneux, Sassy

    2013-04-01

    Internationally, calls for feedback of findings to be made an 'ethical imperative' or mandatory have been met with both strong support and opposition. Challenges include differences in issues by type of study and context, disentangling between aggregate and individual study results, and inadequate empirical evidence on which to draw. In this paper we present data from observations and interviews with key stakeholders involved in feeding back aggregate study findings for two Phase II malaria vaccine trials among children under the age of 5 years old on the Kenyan Coast. In our setting, feeding back of aggregate findings was an appreciated set of activities. The inclusion of individual results was important from the point of view of both participants and researchers, to reassure participants of trial safety, and to ensure that positive results were not over-interpreted and that individual level issues around blinding and control were clarified. Feedback sessions also offered an opportunity to re-evaluate and re-negotiate trial relationships and benefits, with potentially important implications for perceptions of and involvement in follow-up work for the trials and in future research. We found that feedback of findings is a complex but key step in a continuing set of social interactions between community members and research staff (particularly field staff who work at the interface with communities), and among community members themselves; a step which needs careful planning from the outset. We agree with others that individual and aggregate results need to be considered separately, and that for individual results, both the nature and value of the information, and the context, including social relationships, need to be taken into account.

  2. Collaboration and involvement of persons with lived experience in planning Canada's At Home/Chez Soi project.

    PubMed

    Nelson, Geoffrey; Macnaughton, Eric; Curwood, Susan Eckerle; Egalité, Nathalie; Voronka, Jijian; Fleury, Marie-Josée; Kirst, Maritt; Flowers, Linsay; Patterson, Michelle; Dudley, Michael; Piat, Myra; Goering, Paula

    2016-03-01

    Planning the implementation of evidence-based mental health services entails commitment to both rigour and community relevance, which entails navigating the challenges of collaboration between professionals and community members in a planning environment which is neither 'top-down' nor 'bottom-up'. This research focused on collaboration among different stakeholders (e.g. researchers, service-providers, persons with lived experience [PWLE]) at five project sites across Canada in the planning of At Home/Chez Soi, a Housing First initiative for homeless people with mental health problems. The research addressed the question of what strategies worked well or less well in achieving successful collaboration, given the opportunities and challenges within this complex 'hybrid' planning environment. Using qualitative methods, 131 local stakeholders participated in key informant or focus group interviews between October 2009 and February 2010. Site researchers identified themes in the data, using the constant comparative method. Strategies that enhanced collaboration included the development of a common vision, values and purpose around the Housing First approach, developing a sense of belonging and commitment among stakeholders, bridging strategies employed by Site Co-ordinators and multiple strategies to engage PWLE. At the same time, a tight timeline, initial tensions, questions and resistance regarding project and research parameters, and lack of experience in engaging PWLE challenged collaboration. In a hybrid planning environment, clear communication and specific strategies are required that flow from an understanding that the process is neither fully participatory nor expert-driven, but rather a hybrid of both.

  3. Factors involved in growth plasticity of cockles Cerastoderma edule (L.), identified by field survey and transplant experiments

    NASA Astrophysics Data System (ADS)

    De Montaudouin, Xavier

    1996-12-01

    In Arcachon Bay, a macrotidal coastal lagoon in southwest France, growth rates of cockles Cerastoderma edule (L.) differ greatly between locations. Sampling of populations at different tidal levels showed that the mean shell length was significantly and positively correlated with immersion time, whereas no correlation was found with population density and microphytobenthos biomass. Transplants of cockles between two intertidal sites were used to examine the relative importance of habitat and site of origin for growth rate and condition index. Artifacts due to manipulation were assessed, i.e. the impact of enclosures on growth, conditon index and mortality. During a 5-mo reciprocal transplant experiment, growth rates of the transplanted cockles and the cockles already present were similar, whereas the sites of origin did not affect growth rate. Condition index, however, displayed significant differences in relation to both transplant and origin sites. During a further 6-mo experiment in which cockles were transplanted from one site to four new sites, growth was mainly influenced by tidal level. These results indicate that net growth started when cockles were immersed 30% of the time. It is concluded that, on the scale of Arcachon Bay (156 km 2), differences in growth and condition between cockle populations are largely phenotypic. Tidal level ( i.e. food supply and emersion stress) accounts for most of these differences, but the existence of genetically or physiologically different populations cannot be excluded.

  4. Planetary surface research with acoustic sounding

    NASA Astrophysics Data System (ADS)

    Krause, C.; Seidensticker, K. J.

    2007-08-01

    Planetary space missions like Rosetta and ExoMars put more and more emphasis on the in-situ investigation of planetary surfaces. The use of mechanical vibrations in the audible frequency range provide a new means to study the structure and properties of the surface layers of terrestrial planets and minor bodies like comets. As the first of this new type of instruments, the Comet Acoustic Surface Sounding Experiment (CASSE) on the Rosetta Lander Philae intends to determine elastic parameters and the structure of the surface layer of the target comet. One drawback of CASSE is unknown possibly weak coupling to the cometary surface. A DFG project is being conducted at the DLR - Deutsches Zentrum für Luft- und Raumfahrt - to test the applicability of planetary penetration instruments like PLUTO, planetary sampling tool, developed for the Mars Express lander Beagle 2, or MUPUS, a heat probe instrument also on Philae, as stronger acoustic sources as well as to develop new methods for the analysis of acoustic data. From the analysis of the polarisation of the recorded acoustic signals it is possible to separate the mixture of different propagating wave types. These identified waves can be used for the determination of mechanical soil properties and near-surface layering. We also will present how acoustic receivers can be used to locate acoustic penetrators or nearby seismic sources using the travel time and/or the polarisation of the acoustic waves.

  5. Acoustic sensor networks for woodpecker localization

    NASA Astrophysics Data System (ADS)

    Wang, H.; Chen, C. E.; Ali, A.; Asgari, S.; Hudson, R. E.; Yao, K.; Estrin, D.; Taylor, C.

    2005-08-01

    Sensor network technology can revolutionize the study of animal ecology by providing a means of non-intrusive, simultaneous monitoring of interaction among multiple animals. In this paper, we investigate design, analysis, and testing of acoustic arrays for localizing acorn woodpeckers using their vocalizations. Each acoustic array consists of four microphones arranged in a square. All four audio channels within the same acoustic array are finely synchronized within a few micro seconds. We apply the approximate maximum likelihood (AML) method to synchronized audio channels of each acoustic array for estimating the direction-of-arrival (DOA) of woodpecker vocalizations. The woodpecker location is estimated by applying least square (LS) methods to DOA bearing crossings of multiple acoustic arrays. We have revealed the critical relation between microphone spacing of acoustic arrays and robustness of beamforming of woodpecker vocalizations. Woodpecker localization experiments using robust array element spacing in different types of environments are conducted and compared. Practical issues about calibration of acoustic array orientation are also discussed.

  6. International Space Station Acoustics - A Status Report

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S.

    2015-01-01

    It is important to control acoustic noise aboard the International Space Station (ISS) to provide a satisfactory environment for voice communications, crew productivity, alarm audibility, and restful sleep, and to minimize the risk for temporary and permanent hearing loss. Acoustic monitoring is an important part of the noise control process on ISS, providing critical data for trend analysis, noise exposure analysis, validation of acoustic analyses and predictions, and to provide strong evidence for ensuring crew health and safety, thus allowing Flight Certification. To this purpose, sound level meter (SLM) measurements and acoustic noise dosimetry are routinely performed. And since the primary noise sources on ISS include the environmental control and life support system (fans and airflow) and active thermal control system (pumps and water flow), acoustic monitoring will reveal changes in hardware noise emissions that may indicate system degradation or performance issues. This paper provides the current acoustic levels in the ISS modules and sleep stations and is an update to the status presented in 2011. Since this last status report, many payloads (science experiment hardware) have been added and a significant number of quiet ventilation fans have replaced noisier fans in the Russian Segment. Also, noise mitigation efforts are planned to reduce the noise levels of the T2 treadmill and levels in Node 3, in general. As a result, the acoustic levels on the ISS continue to improve.

  7. Acoustic Characterization of Compact Jet Engine Simulator Units

    NASA Technical Reports Server (NTRS)

    Doty, Michael J.; Haskin, Henry H.

    2013-01-01

    Two dual-stream, heated jet, Compact Jet Engine Simulator (CJES) units are designed for wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. The newly fabricated CJES units are characterized with a series of acoustic and flowfield investigations to ensure successful operation with minimal rig noise. To limit simulator size, consistent with a 5.8% HWB model, the CJES units adapt Ultra Compact Combustor (UCC) technology developed at the Air Force Research Laboratory. Stable and controllable operation of the combustor is demonstrated using passive swirl air injection and backpressuring of the combustion chamber. Combustion instability tones are eliminated using nonuniform flow conditioners in conjunction with upstream screens. Through proper flow conditioning, rig noise is reduced by more than 20 dB over a broad spectral range, but it is not completely eliminated at high frequencies. The low-noise chevron nozzle concept designed for the HWB test shows expected acoustic benefits when installed on the CJES unit, and consistency between CJES units is shown to be within 0.5 dB OASPL.

  8. Acoustic mapping of ocean currents using networked distributed sensors.

    PubMed

    Huang, Chen-Fen; Yang, T C; Liu, Jin-Yuan; Schindall, Jeff

    2013-09-01

    Distributed underwater sensors are expected to provide oceanographic monitoring over large areas. As fabrication technology advances, low cost sensors will be available for many uses. The sensors communicate to each other and are networked using acoustic communications. This paper first studies the performance of such systems for current measurements using tomographic inversion approaches to compare with that of a conventional system which distributes the sensors on the periphery of the area of interest. It then proposes two simple signal processing methods for ocean current mapping (using distributed networked sensors) aimed at real-time in-buoy processing. Tomographic inversion generally requires solving a challenging high dimensional inverse problem, involving substantial computations. Given distributed sensors, currents can be constructed locally based on data from neighboring sensors. It is shown using simulated data that similar results are obtained using distributed processing as using conventional tomographic approaches. The advantage for distributed systems is that by increasing the number of nodes, one gains a much more improved performance. Furthermore, distributed systems use much less energy than a conventional tomographic system for the same area coverage. Experimental data from an acoustic communication and networking experiment are used to demonstrate the feasibility of acoustic current mapping.

  9. Preliminary theoretical acoustic and rf sounding calculations for MILL RACE

    SciTech Connect

    Warshaw, S.I.; Dubois, P.F.

    1981-11-02

    As participant in DOE/ISA's Ionospheric Monitoring Program, LLNL has the responsibility of providing theoretical understanding and calculational support for experimental activities carried out by Los Alamos National Laboratory in using ionospheric sounders to remotely detect violent atmospheric phenomena. We have developed a system of interconnected computer codes which simulate the entire range of atmospheric and ionospheric processes involved in this remote detection procedure. We are able to model the acoustic pulse shape from an atmospheric explosion, the subsequent nonlinear transport of this energy to all parts of the immediate atmosphere including the ionosphere, and the propagation of high-frequency ratio waves through the acoustically perturbed ionosphere. Los Alamos' coverage of DNA's MILL RACE event provided an excellent opportunity to assess the credibility of the calculational system to correctly predict how ionospheric sounders would respond to a surface-based chemical explosion. In this experiment, 600 tons of high explosive were detonated at White Sands Missile Range at 12:35:40 local time on 16 September 1981. Vertical incidence rf phase sounders and bistatic oblique incidence rf sounders fielded by Los Alamos and SRI International throughout New Mexico and southern Colorado detected the ionospheric perturbation that ensued. A brief account of preliminary calculations of the acoustic disturbance and the predicted ionospheric sounder signatures for MILL RACE is presented. (WHK)

  10. Acoustically Driven Magnetized Target Fusion At General Fusion: An Overview

    NASA Astrophysics Data System (ADS)

    O'Shea, Peter; Laberge, M.; Donaldson, M.; Delage, M.; the Fusion Team, General

    2016-10-01

    Magnetized Target Fusion (MTF) involves compressing an initial magnetically confined plasma of about 1e23 m-3, 100eV, 7 Tesla, 20 cm radius, >100 μsec life with a 1000x volume compression in 100 microseconds. If near adiabatic compression is achieved, the final plasma of 1e26 m-3, 10keV, 700 Tesla, 2 cm radius, confined for 10 μsec would produce interesting fusion energy gain. General Fusion (GF) is developing an acoustic compression system using pneumatic pistons focusing a shock wave on the CT plasma in the center of a 3 m diameter sphere filled with liquid lead-lithium. Low cost driver, straightforward heat extraction, good tritium breeding ratio and excellent neutron protection could lead to a practical power plant. GF (65 employees) has an active plasma R&D program including both full scale and reduced scale plasma experiments and simulation of both. Although acoustic driven compression of full scale plasmas is the end goal, present compression studies use reduced scale plasmas and chemically accelerated Aluminum liners. We will review results from our plasma target development, motivate and review the results of dynamic compression field tests and briefly describe the work to date on the acoustic driver front.

  11. Acoustics and Oceanographic Observations Collected During the QPE Experiment by Research Vessels OR1, OR2 and OR3 in the East China Sea in the Summer of 2009

    DTIC Science & Technology

    2010-08-01

    OR1, OR2 and OR3 in the East China Sea in the Summer of 2009 by Arthur E. Newhall1, James F. Lynch1, Glen G. Gawarkiewicz1, Timothy F. Duda1, Neil M...Vessels OR1, OR2, and OR3 in the East China Sea in the Summer of 2009 Arthur E. Newhall, James F. Lynch, Glen G. Gawarkiewicz,  Timothy F. Duda, Neil M...number: N00014­08­1­0763 Keywords:   QPE experiment and mooring information   acoustic and oceanography data in the East China  Sea   quantifying

  12. Dose reconstruction for weapons experiments involving {sup 140}La at Los Alamos National Laboratory, 1944-1962

    SciTech Connect

    Kraig, D.J.

    1997-10-01

    A series of 254 weapons design experiments was conducted by Los Alamos National Laboratory from 1944 through 1962 and resulted in the dispersal of approximately 11 PBq (300 kCi) of radioactive {sup 140}La. All shots occurred at Point Able in Bayo Canyon, east of the Los Alamos townsite. Public interest and the Government Accounting Office probe precipitated a dose reconstruction to assess potential exposures to members of the public. The information available for each shot included explosive charge size, date and time of explosion, and shot activity. Detailed meteorological data were not available for the majority of the shots, requiring the development of statistically representative meteorological data. A wind rose was developed specific to the afternoon-evening time of the shots, and the wind frequency in each sector was used to determine the fraction of activity dispersed towards each hypothetical receptor. HOTSPOT 7, a Gaussian plume-based dispersion model, was used to determine the average dose per sector per unit of shot activity. The dose from penetrating radiation from ground-deposited {sup 140}La was greater by several orders of magnitude than the dose from inhalation and immersion. The highest doses to a permanent resident probably occurred in the easternmost part of the Los Alamos townsite. The highest annual dose occurred in 1955 and was approximately 0.23 mSv. Assuming an individual had been at the location of maximum potential exposure in the Los Alamos townsite continuously throughout the experiments, the total dose from the 18-y series would have been approximately 1.4 mSv with an average dose of approximately 0.09 mSv y{sup -1}. Doses at nearby Totavi trailer park, San Clara Pueblo, and Santa Clara Pueblo were approximately 75%, 40%, and 15%, respectively, of those at Los Alamos. Visitors to nearby public areas received negligible doses. 11 refs., 6 figs., 4 tabs.

  13. 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.

  14. Involving stakeholders in the commissioning and implementation of fishery science projects: experiences from the U.K. Fisheries Science Partnership.

    PubMed

    Armstrong, M J; Payne, A I L; Deas, B; Catchpole, T L

    2013-10-01

    Following from similar initiatives worldwide, the U.K.'s Fisheries Science Partnership (FSP) was established in 2003 to provide the fishing industry with opportunities to propose and participate in scientific studies in collaboration with fishery scientists. Key concepts were that most of the available funding would support industry participation, that industry, not scientists, would come up with the ideas for projects, and that commercial fishing vessels and fishing methods would be used to address specific concerns of the fishing industry in a scientifically controlled manner. Nearly 100 projects had been commissioned by March 2012, covering annual time-series surveys of stocks subject to traditional assessment, and ad hoc projects on, e.g. gear selectivity, discard survival, tagging and migration and fishery development. The extent to which the results of the projects have been used by stakeholders, fishery scientists and fishery managers at a national and E.U. level is evaluated, along with the degree of industry interest and involvement, and reasons are identified for successes or failures in the uptake of the results into management and policy. Finally, the question is posed whether the programme has been successful in improving the engagement of the fishing community in the science-management process and in fostering communication and greater trust between fishers, scientists and managers.

  15. Acoustic Translation of an Acoustically Levitated Sample

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  16. Effect of acoustic field parameters on arc acoustic binding during ultrasonic wave-assisted arc welding.

    PubMed

    Xie, Weifeng; Fan, Chenglei; Yang, Chunli; Lin, Sanbao

    2016-03-01

    As a newly developed arc welding method, power ultrasound has been successfully introduced into arc and weld pool during ultrasonic wave-assisted arc welding process. The advanced process for molten metals can be realized by utilizing additional ultrasonic field. Under the action of the acoustic wave, the plasma arc as weld heat source is regulated and its characteristics make an obvious change. Compared with the conventional arc, the ultrasonic wave-assisted arc plasma is bound significantly and becomes brighter. To reveal the dependence of the acoustic binding force on acoustic field parameters, a two-dimensional acoustic field model for ultrasonic wave-assisted arc welding device is established. The influences of the radiator height, the central pore radius, the radiator radius, and curvature radius or depth of concave radiator surface are discussed using the boundary element method. Then the authors analyze the resonant mode by this relationship curve between acoustic radiation power and radiator height. Furthermore, the best acoustic binding ability is obtained by optimizing the geometric parameters of acoustic radiator. In addition, three concave radiator surfaces including spherical cap surface, paraboloid of revolution, and rotating single curved surface are investigated systematically. Finally, both the calculation and experiment suggest that, to obtain the best acoustic binding ability, the ultrasonic wave-assisted arc welding setup should be operated under the first resonant mode using a radiator with a spherical cap surface, a small central pore, a large section radius and an appropriate curvature radius.

  17. Acoustic Seaglider: PhilSea10 Data Analysis

    DTIC Science & Technology

    2016-06-13

    understanding that the navigation and the ocean sound speed and currents be jointly determined. LONG-TERM GOALS Within the Ocean Acoustics Deep Water... temperature and salinity were deployed (Figure 1). General objectives of the experiment are to understand the acoustic propagation in the...an acoustic recording system (ARS) to record the moored source transmissions, as well as temperature , salinity and pressure sensors (from which

  18. Acoustic Microfluidics for Bioanalytical Application

    NASA Astrophysics Data System (ADS)

    Lopez, Gabriel

    2013-03-01

    This talk will present new methods the use of ultrasonic standing waves in microfluidic systems to manipulate microparticles for the purpose of bioassays and bioseparations. We have recently developed multi-node acoustic focusing flow cells that can position particles into many parallel flow streams and have demonstrated the potential of such flow cells in the development of high throughput, parallel flow cytometers. These experiments show the potential for the creation of high throughput flow cytometers in applications requiring high flow rates and rapid detection of rare cells. This talk will also present the development of elastomeric capture microparticles and their use in acoustophoretic separations. We have developed simple methods to form elastomeric particles that are surface functionalized with biomolecular recognition reagents. These compressible particles exhibit negative acoustic contrast in ultrasound when suspended in aqueous media, blood serum or diluted blood. These particles can be continuously separated from cells by flowing them through a microfluidic device that uses an ultrasonic standing wave to align the blood cells, which exhibit positive acoustic contrast, at a node in the acoustic pressure distribution while aligning the negative acoustic contrast elastomeric particles at the antinodes. Laminar flow of the separated particles to downstream collection ports allows for collection of the separated negative contrast particles and cells. Separated elastomeric particles were analyzed via flow cytometry to demonstrate nanomolar detection for prostate specific antigen in aqueous buffer and picomolar detection for IgG in plasma and diluted blood samples. This approach has potential applications in the development of rapid assays that detect the presence of low concentrations of biomarkers (including biomolecules and cells) in a number of biological sample types. We acknowledge support through the NSF Research Triangle MRSEC.

  19. Study Acoustic Emissions from Composites

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Workman, Gary L.

    1997-01-01

    The nondestructive evaluation (NDE) of future propulsion systems utilizing advanced composite structures for the storage of cryogenic fuels, such as liquid hydrogen or oxygen, presents many challenges. Economic justification for these structures requires, light weight, reusable components with an infrastructure allowing periodic evaluation of structural integrity after enduring demanding stresses during operation. A major focus has been placed on the use of acoustic emission NDE to detect propagating defects, in service, necessitating an extensive study into characterizing the nature of acoustic signal propagation at very low temperatures and developing the methodology of applying AE sensors to monitor cryogenic components. This work addresses the question of sensor performance in the cryogenic environment. Problems involving sensor mounting, spectral response and durability are addressed. The results of this work provides a common point of measure from which sensor selection can be made when testing composite components at cryogenic temperatures.

  20. Acoustic modes in fluid networks

    NASA Technical Reports Server (NTRS)

    Michalopoulos, C. D.; Clark, Robert W., Jr.; Doiron, Harold H.

    1992-01-01

    Pressure and flow rate eigenvalue problems for one-dimensional flow of a fluid in a network of pipes are derived from the familiar transmission line equations. These equations are linearized by assuming small velocity and pressure oscillations about mean flow conditions. It is shown that the flow rate eigenvalues are the same as the pressure eigenvalues and the relationship between line pressure modes and flow rate modes is established. A volume at the end of each branch is employed which allows any combination of boundary conditions, from open to closed, to be used. The Jacobi iterative method is used to compute undamped natural frequencies and associated pressure/flow modes. Several numerical examples are presented which include acoustic modes for the Helium Supply System of the Space Shuttle Orbiter Main Propulsion System. It should be noted that the method presented herein can be applied to any one-dimensional acoustic system involving an arbitrary number of branches.

  1. The oxidized soot surface: theoretical study of desorption mechanisms involving oxygenated functionalities and comparison with temperature programed desorption experiments.

    PubMed

    Barco, Gianluca; Maranzana, Andrea; Ghigo, Giovanni; Causà, Mauro; Tonachini, Glauco

    2006-11-21

    The desorption mechanism for oxygenated functionalities on soot is investigated by quantum mechanical calculations on functionalized polycyclic aromatic hydrocarbon (PAH) models and compared with recently published temperature programed desorption-mass spectrometry results. Substituents on PAHs of increasing size (up to 46 carbon atoms in the parent PAH) are chosen to reproduce the local features of an oxidized graphenic soot platelet. Initially, the study is carried out on unimolecular fragmentation (extrusion, in some cases) processes producing HO, CO, or CO2, in model ketones, carboxylic acids, lactones, anhydrides, in one aldehyde, one peroxyacid, one hydroperoxide, one secondary alcohol, and one phenol. Then, a bimolecular process is considered for one of the carboxylic acids. Furthermore, some cooperative effect which can take place by involving two vicinal carboxylic groups (derived from anhydride hydrolysis) is investigated for other four bifunctionalized models. The comparison between the computed fragmentation (desorption) barriers for the assessed mechanisms and the temperature at which maxima occur in TPD spectra (for HO, CO, or CO2 desorption) offers a suggestion for the assignment of these maxima to specific functional groups, i.e., a key to the description of the oxidized surface. Notably, the computations suggest that (1) the desorption mode from a portion of a graphenic platelet functionalized by a carboxylic or lactone groups is significantly dependent from the chemical and geometric local environment. Consequently, we propose that (2) not all carboxylic groups go lost at the relatively low temperatures generally stated, and (3) lactone groups can be identified as producing not only CO2 but also CO.

  2. Broadband acoustic cloak for ultrasound waves.

    PubMed

    Zhang, Shu; Xia, Chunguang; Fang, Nicholas

    2011-01-14

    Invisibility devices based on coordinate transformation have opened up a new field of considerable interest. We present here the first practical realization of a low-loss and broadband acoustic cloak for underwater ultrasound. This metamaterial cloak is constructed with a network of acoustic circuit elements, namely, serial inductors and shunt capacitors. Our experiment clearly shows that the acoustic cloak can effectively bend the ultrasound waves around the hidden object, with reduced scattering and shadow. Because of the nonresonant nature of the building elements, this low-loss (∼6  dB/m) cylindrical cloak exhibits invisibility over a broad frequency range from 52 to 64 kHz. Furthermore, our experimental study indicates that this design approach should be scalable to different acoustic frequencies and offers the possibility for a variety of devices based on coordinate transformation.

  3. 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.

  4. Drag Measurements of Porous Plate Acoustic Liners

    NASA Technical Reports Server (NTRS)

    Wolter, John D.

    2005-01-01

    This paper presents the results of direct drag measurements on a variety of porous plate acoustic liners. The existing literature describes numerous studies of drag on porous walls with injection or suction, but relatively few of drag on porous plates with neither injection nor suction. Furthermore, the porosity of the porous plate in existing studies is much lower than typically used in acoustic liners. In the present work, the acoustic liners consisted of a perforated face sheet covering a bulk acoustic absorber material. Factors that were varied in the experiment were hole diameter, hole pattern, face sheet thickness, bulk material type, and size of the gap (if any) between the face sheet and the absorber material.

  5. 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

  6. Involving lay community researchers in epidemiological research: experiences from a seroprevalence study among sub-Saharan African migrants.

    PubMed

    Nöstlinger, Christiana; Loos, Jasna

    2016-01-01

    Community-based participatory research (CBPR) has received considerable attention during past decades as a method to increase community ownership in research and prevention. We discuss its application to epidemiological research using the case of second-generation surveillance conducted among sub-Saharan African (SSA) migrants in Antwerp city. To inform evidence-based prevention planning for this target group, this HIV-prevalence study used two-stage time-location sampling preceded by formative research. Extensive collaborative partnerships were built with community organizations, a Community Advisory Board provided input throughout the project, and community researchers were trained to participate in all phases of the seroprevalence study. Valid oral fluid samples for HIV testing were collected among 717 SSA migrants and linked to behavioural data assessed through an anonymous survey between December 2013 and August 2014. A qualitative content analysis of various data sources (extensive field notes, minutes of intervision, and training protocols) collected at 77 data collection visits in 51 settings was carried out to describe experiences with challenges and opportunities inherent to the CBPR approach at three crucial stages of the research process: building collaborative partnerships; implementing the study; dissemination of findings including prevention planning. The results show that CBPR is feasible in conducting scientifically sound epidemiological research, but certain requirements need to be in place. These include among others sufficient resources to train, coordinate, and supervise community researchers; continuity in the implementation; transparency about decision-taking and administrative procedures, and willingness to share power and control over the full research process. CBPR contributed to empowering community researchers on a personal level, and to create greater HIV prevention demand in the SSA communities.

  7. Involving lay community researchers in epidemiological research: experiences from a seroprevalence study among sub-Saharan African migrants

    PubMed Central

    Nöstlinger, Christiana; Loos, Jasna

    2016-01-01

    ABSTRACT Community-based participatory research (CBPR) has received considerable attention during past decades as a method to increase community ownership in research and prevention. We discuss its application to epidemiological research using the case of second-generation surveillance conducted among sub-Saharan African (SSA) migrants in Antwerp city. To inform evidence-based prevention planning for this target group, this HIV-prevalence study used two-stage time-location sampling preceded by formative research. Extensive collaborative partnerships were built with community organizations, a Community Advisory Board provided input throughout the project, and community researchers were trained to participate in all phases of the seroprevalence study. Valid oral fluid samples for HIV testing were collected among 717 SSA migrants and linked to behavioural data assessed through an anonymous survey between December 2013 and August 2014. A qualitative content analysis of various data sources (extensive field notes, minutes of intervision, and training protocols) collected at 77 data collection visits in 51 settings was carried out to describe experiences with challenges and opportunities inherent to the CBPR approach at three crucial stages of the research process: building collaborative partnerships; implementing the study; dissemination of findings including prevention planning. The results show that CBPR is feasible in conducting scientifically sound epidemiological research, but certain requirements need to be in place. These include among others sufficient resources to train, coordinate, and supervise community researchers; continuity in the implementation; transparency about decision-taking and administrative procedures, and willingness to share power and control over the full research process. CBPR contributed to empowering community researchers on a personal level, and to create greater HIV prevention demand in the SSA communities. PMID:26885938

  8. Development of the seafloor acoustic ranging system

    NASA Astrophysics Data System (ADS)

    Osada, Y.; Kido, M.; Fujimoto, H.

    2007-12-01

    We have developed a seafloor acoustic ranging system, which simulates an operation with the DONET (Development of Dense Ocean-floor Network System for Earthquake and Tsunami) cable, to monitor seafloor crustal movement. The seafloor acoustic ranging system was based on the precise acoustic transponder (PXP). We have a few problems for the improvement of the resolution. One thing is the variation of sound speed. Another is the bending of ray path. A PXP measures horizontal distances on the seafloor from the round trip travel times of acoustic pulses between pairs of PXP. The PXP was equipped with the pressure, temperature gauge and tilt-meter. The variation of sound speed in seawater has a direct effect on the measurement. Therefore we collect the data of temperature and pressure. But we don't collect the data of salinity because of less influence than temperature and pressure. Accordingly a ray path of acoustic wave tends to be bent upward in the deep sea due to the Snell's law. As the acoustic transducer of each PXPs held about 3.0m above the seafloor, the baseline is too long for altitude from the seafloor. In this year we carried out the experiment for the seafloor acoustic ranging system. We deployed two PXPs at about 750m spacing on Kumano-nada. The water depth is about 2050m. We collected the 660 data in this experiment during one day. The round trip travel time show the variation with peak-to-peak amplitude of about 0.03msec. It was confirmed to explain the majority in this change by the change in sound speed according to the temperature and pressure. This results shows the resolution of acoustic measurements is +/-2mm. Acknowledgement This study is supported by 'DONET' of Ministry of Education, Culture, Sports, Science and Technology.

  9. Nearfield Acoustical Holography

    NASA Astrophysics Data System (ADS)

    Hayek, Sabih I.

    Nearfield acoustical holography (NAH) is a method by which a set of acoustic pressure measurements at points located on a specific surface (called a hologram) can be used to image sources on vibrating surfaces on the acoustic field in three-dimensional space. NAH data are processed to take advantage of the evanescent wavefield to image sources that are separated less that one-eighth of a wavelength.

  10. Deep Water Acoustics

    DTIC Science & Technology

    2016-06-28

    Estimates of basin-wide sound speed ( temperature ) fields obtained by the combination of acoustic, altimetry, and other data types with ocean...of acoustic coherence at long ranges in the ocean. Estimates of basin-wide sound speed ( temperature ) fields obtained by the combination of acoustic...index.html Award Number N00014-13-1-0053 LONG-TERM GOALS The ultimate limitations to the performance of long-range sonar are due to ocean sound speed

  11. Acoustic Communications (ACOMMS) ATD

    DTIC Science & Technology

    2016-06-14

    Acoustic Communications (ACOMMS) ATD Tam Nguyen 2531 Jefferson Davis Hwy Arlington, VA 22242 phone: (703) 604-6013 ext 520 fax: (703) 604-6056...email: NguyenTL@navsea.navy.mil Award # N0001499PD30007 LONG-TERM GOALS The goal of the recently completed Acoustic Communications Advanced...Technology Demonstration program (ACOMMS ATD) was to demonstrate long range and moderate data rate underwater acoustic communications between a submarine

  12. Deep Water Ocean Acoustics

    DTIC Science & Technology

    2016-04-30

    OASIS, INC. 1 Report No. QSR-14C0172-Ocean Acoustics-043016 Quarterly Progress Report Technical and Financial 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...improve our understanding. During the past few years, the physics effects studied have been three-dimensional propagation on global scales, deep water

  13. 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.

  14. 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.

  15. Low frequency acoustic microscope

    DOEpatents

    Khuri-Yakub, Butrus T.

    1986-11-04

    A scanning acoustic microscope is disclosed for the detection and location of near surface flaws, inclusions or voids in a solid sample material. A focused beam of acoustic energy is directed at the sample with its focal plane at the subsurface flaw, inclusion or void location. The sample is scanned with the beam. Detected acoustic energy specularly reflected and mode converted at the surface of the sample and acoustic energy reflected by subsurface flaws, inclusions or voids at the focal plane are used for generating an interference signal which is processed and forms a signal indicative of the subsurface flaws, inclusions or voids.

  16. 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

  17. Pattern-formation under acoustic driving forces

    NASA Astrophysics Data System (ADS)

    Valverde, Jose Manuel

    2015-07-01

    Chemical and metallurgical processes enhanced by high intensity acoustic waves, thermoacoustic engines and refrigerators, fuel rods in nuclear reactors, heat exchanger tubes, offshore and vibrating structures, solar thermal collectors, acoustic levitators, microfluidic devices, cycling, musical acoustics, blood flow through veins/arteries, hearing in the mammalian ear, carbon nanotube loudspeakers, etc. The evolution of a myriad of processes involving the oscillation of viscous fluids in the presence of solid boundaries is up to a certain extent influenced by acoustic streaming. In addition to the sound field, viscous energy dissipation at the fluid-solid boundary causes a time-independent fluid circulation, which can lead to a significant enhancement of heat, mass and momentum transfer at large oscillation amplitudes. A particularly relevant phenomenon that can be notably affected by acoustic streaming is the promotion of sound waves by temperature gradients or viceversa (thermoacoustics), which is at the basis of potentially efficient and environmental friendly engines and refrigerators that have attracted a renewed interest in the last years. In the present manuscript, historical developments and the underlying basic physics behind acoustic streaming and thermoacoustics are reviewed from an unifying perspective.

  18. An acoustic emission study of plastic deformation in polycrystalline aluminium

    NASA Technical Reports Server (NTRS)

    Bill, R. C.; Frederick, J. R.; Felbeck, D. K.

    1979-01-01

    Acoustic emission experiments were performed on polycrystalline and single crystal 99.99% aluminum while undergoing tensile deformation. It was found that acoustic emission counts as a function of grain size showed a maximum value at a particular grain size. Furthermore, the slip area associated with this particular grain size corresponded to the threshold level of detectability of single dislocation slip events. The rate of decline in acoustic emission activity as grain size is increased beyond the peak value suggests that grain boundary associated dislocation sources are giving rise to the bulk of the detected acoustic emissions.

  19. Acoustic resonance spectroscopy for the advanced undergraduate laboratory

    NASA Astrophysics Data System (ADS)

    Franco-Villafañe, J. A.; Flores-Olmedo, E.; Báez, G.; Gandarilla-Carrillo, O.; Méndez-Sánchez, R. A.

    2012-11-01

    We present a simple experiment that allows advanced undergraduates to learn the principles and applications of spectroscopy. The technique, known as acoustic resonance spectroscopy, is applied to study a vibrating rod. The setup includes electromagnetic-acoustic transducers, an audio amplifier and a vector network analyzer. Typical results of compressional, torsional and bending waves are analyzed and compared with analytical results.

  20. Ocean Dynamics and Acoustic Variability in East China Sea

    DTIC Science & Technology

    2015-09-30

    Ocean ...N00014-13-1-0510 http://scrippsscholars.ucsd.edu/hcsong LONG TERM GOALS Study the effects of ocean dynamics on acoustic propagation and underwater...communication in the region of East China Sea (ECS). OBJECTIVE Conduct a joint shallow water acoustic experiment with KIOST (Korea Institute of Ocean

  1. Acoustic telemetry and fisheries management

    USGS Publications Warehouse

    Crossin, Glenn T.; Heupel, Michelle R.; Holbrook, Christopher; Hussey, Nigel E.; Lowerre-Barbieri, Susan K; Nguyen, Vivian M.; Raby, Graham D.; Cooke, Steven J.

    2017-01-01

    This paper reviews the use of acoustic telemetry as a tool for addressing issues in fisheries management, and serves as the lead to the special Feature Issue of Ecological Applications titled “Acoustic Telemetry and Fisheries Management”. Specifically, we provide an overview of the ways in which acoustic telemetry can be used to inform issues central to the ecology, conservation, and management of exploited and/or imperiled fish species. Despite great strides in this area in recent years, there are comparatively few examples where data have been applied directly to influence fisheries management and policy. We review the literature on this issue, identify the strengths and weaknesses of work done to date, and highlight knowledge gaps and difficulties in applying empirical fish telemetry studies to fisheries policy and practice. We then highlight the key areas of management and policy addressed, as well as the challenges that needed to be overcome to do this. We conclude with a set of recommendations about how researchers can, in consultation with stock assessment scientists and managers, formulate testable scientific questions to address and design future studies to generate data that can be used in a meaningful way by fisheries management and conservation practitioners. We also urge the involvement of relevant stakeholders (managers, fishers, conservation societies, etc.) early on in the process (i.e. in the co-creation of research projects), so that all priority questions and issues can be addressed effectively.

  2. Acoustic Telemetry and Fisheries Management.

    PubMed

    Crossin, Glenn T; Heupel, Michelle R; Holbrook, Christopher M; Hussey, Nigel E; Lowerre-Barbieri, Susan K; Nguyen, Vivian M; Raby, Graham D; Cooke, Steven J

    2017-03-15

    This paper reviews the use of acoustic telemetry as a tool for addressing issues in fisheries management, and serves as the lead to the special Feature Issue of Ecological Applications titled "Acoustic Telemetry and Fisheries Management". Specifically, we provide an overview of the ways in which acoustic telemetry can be used to inform issues central to the ecology, conservation, and management of exploited and/or imperiled fish species. Despite great strides in this area in recent years, there are comparatively few examples where data have been applied directly to influence fisheries management and policy. We review the literature on this issue, identify the strengths and weaknesses of work done to date, and highlight knowledge gaps and difficulties in applying empirical fish telemetry studies to fisheries policy and practice. We then highlight the key areas of management and policy addressed, as well as the challenges that needed to be overcome to do this. We conclude with a set of recommendations about how researchers can, in consultation with stock assessment scientists and managers, formulate testable scientific questions to address and design future studies to generate data that can be used in a meaningful way by fisheries management and conservation practitioners. We also urge the involvement of relevant stakeholders (managers, fishers, conservation societies, etc.) early on in the process (i.e. in the co-creation of research projects), so that all priority questions and issues can be addressed effectively. This article is protected by copyright. All rights reserved.

  3. Humanitarian mine detection by acoustic resonance

    SciTech Connect

    Kercel, S.W.

    1998-03-01

    The JASON Committee at MITRE Corp. was tasked by DARPA to inquire into suitable technologies for humanitarian mine detection. Acoustic resonance was one of the very few technologies that the JASONs determined might be promising for the task, but was as yet unexplored at the time that they conducted their inquiry. The objective of this Seed Money investigation into acoustic resonance was to determine if it would be feasible to use acoustic resonance to provide an improvement to present methods for humanitarian mine detection. As detailed in this report, acoustic resonance methods do not appear to be feasible for this task. Although acoustic resonant responses are relatively easy to detect when they exist, they are very difficult to excite by the non-contact means that must be used for buried objects. Despite many different attempts, this research did not discover any practical means of using sound to excite resonant responses in objects known to have strong resonances. The shaker table experiments did see an effect that might be attributable to the resonance of the object under test, but the effect was weak, and exploited the a priori knowledge of the resonant frequency of the object under test to distinguish it from the background. If experiments that used objects known to have strong acoustic resonances produced such marginal results, this does not seem to be a practical method to detect objects with weak resonances or non-existent resonances. The results of this work contribute to the ORNL countermine initiative. ORNL is exploring several unconventional mine detection technologies, and is proposed to explore others. Since this research has discovered some major pitfalls in non-metallic mine detection, this experience will add realism to other strategies proposed for mine detection technologies. The experiment provided hands-on experience with inert plastic mines under field conditions, and gives ORNL additional insight into the problems of developing practical

  4. Bioeffects due to acoustic droplet vaporization

    NASA Astrophysics Data System (ADS)

    Bull, Joseph

    2015-11-01

    Encapsulated micro- and nano-droplets can be vaporized via ultrasound, a process termed acoustic droplet vaporization. Our interest is primarily motivated by a developmental gas embolotherapy technique for cancer treatment. In this methodology, infarction of tumors is induced by selectively formed vascular gas bubbles that arise from the acoustic vaporization of vascular microdroplets. Additionally, the microdroplets may be used as vehicles for localized drug delivery, with or without flow occlusion. In this talk, we examine the dynamics of acoustic droplet vaporization through experiments and theoretical/computational fluid mechanics models, and investigate the bioeffects of acoustic droplet vaporization on endothelial cells and in vivo. Early timescale vaporization events, including phase change, are directly visualized using ultra-high speed imaging, and the influence of acoustic parameters on droplet/bubble dynamics is discussed. Acoustic and fluid mechanics parameters affecting the severity of endothelial cell bioeffects are explored. These findings suggest parameter spaces for which bioeffects may be reduced or enhanced, depending on the objective of the therapy. This work was supported by NIH grant R01EB006476.

  5. The Acoustical Environment.

    ERIC Educational Resources Information Center

    Smith, Melissa

    Asserting that without an adequate acoustical environment, learning activities can be hindered, this paper reviews the literature on classroom acoustics, particularly noise, reverberation, signal-to-noise ratio, task performance, and recommendations for improvement. Through this review, the paper seeks to determine whether portable classrooms…

  6. Cystic acoustic schwannomas.

    PubMed

    Lunardi, P; Missori, P; Mastronardi, L; Fortuna, A

    1991-01-01

    Three cases with large space-occupying cysts in the cerebellopontine angle are reported. CT and MRI findings were not typical for acoustic schwannomas but at operation, besides the large cysts, small acoustic schwannomas could be detected and removed. The clinical and neuroradiological features of this unusual variety and the CT and MRI differential diagnosis of cerebellopontine angle lesions are discussed.

  7. Acoustic Noise Prediction of the Amine Swingbed ISS ExPRESS Rack Payload

    NASA Technical Reports Server (NTRS)

    Welsh, David; Smith, Holly; Wang, Shuo

    2010-01-01

    Acoustics plays a vital role in maintaining the health, safety, and comfort of crew members aboard the International Space Station (ISS). In order to maintain this livable and workable environment, acoustic requirements have been established to ensure that ISS hardware and payload developers account for the acoustic emissions of their equipment and develop acoustic mitigations as necessary. These requirements are verified by an acoustic emissions test of the integrated hardware. The Amine Swingbed ExPRESS (Expedite the PRocessing of ExperimentS to Space) rack payload creates a unique challenge to the developers in that the payload hardware is transported to the ISS in phases, making an acoustic emissions test on the integrated flight hardware impossible. In addition, the payload incorporates a high back pressure fan and a diaphragm vacuum pump, which are recognized as significant and complex noise sources. In order to accurately predict the acoustic emissions of the integrated payload, the individual acoustic noise sources and paths are first characterized. These characterizations are conducted though a series of acoustic emissions tests on the individual payload components. Secondly, the individual acoustic noise sources and paths are incorporated into a virtual model of the integrated hardware. The virtual model is constructed with the use of hybrid method utilizing the Finite Element Acoustic (FEA) and Statistical Energy Analysis (SEA) techniques, which predict the overall acoustic emissions. Finally, the acoustic model is validated though an acoustic characterization test performed on an acoustically similar mock-up of the flight unit. The results of the validated acoustic model are then used to assess the acoustic emissions of the flight unit and define further acoustic mitigation efforts.

  8. Acoustic tomography. Laboratory technique Implementation.

    NASA Astrophysics Data System (ADS)

    Galvis, Jorge; Carvajal, Jenny

    2010-05-01

    From geomechanical tests carried out on rocks it is possible to determine its physico-mechanical properties, which relate the strain and applied stress; even so, conventional tests do not allow to identify how stress is distributed and how it has affected porous media. Today, techniques like acoustic tomography widely used in medicine, geophysics and others sciences, generates images by sections of the interior of a body. Acoustic tomography allows inferring the stress state within porous media; since wave velocities are closely related to media density, if a stress is applied to a rock, it will generate grains compaction and this will be showed by an increase of wave velocity. Implementation was conducted on rock plugs under diverse stress fields, simultaneously recording P-wave velocities (Compressional) on perpendicular planes to sample vertical axis. Transmission and reception of acoustic waves through porous media were done by piezoelectric crystals (PZT) used as sensors. A transmitting crystal excited by a voltage pulse causes a mechanical vibration, which travels across media; this is known as inverse piezoelectric effect. This vibration is recorded by a receiving crystal in which the direct piezoelectric effect appears; which dictates that if a piezoelectric is disturbed mechanically, an electrical signal between its terminals will appear. This electrical signal is used to obtain the wave velocity. Nevertheless, acoustic tomography corresponds to one of those called inverse Problems that arise when from observed data the model parameters must be obtained; in this way, tomography involves iterative reconstruction techniques (ART or SIRT) which are projections of observed data and its later inversion. Obtained results are cross-sectional images of velocity within the rock. In these images it is possible to identify where stress has a greater concentration observing the color map generated; thus, a greater velocity density area corresponding to a greater

  9. Acoustic suspension system

    NASA Technical Reports Server (NTRS)

    Lee, M. C.; Wang, T. G. (Inventor)

    1983-01-01

    An acoustic levitation system is described, with single acoustic source and a small reflector to stably levitate a small object while the object is processed as by coating or heating it. The system includes a concave acoustic source which has locations on opposite sides of its axis that vibrate towards and away from a focal point to generate a converging acoustic field. A small reflector is located near the focal point, and preferably slightly beyond it, to create an intense acoustic field that stably supports a small object near the reflector. The reflector is located about one-half wavelength from the focal point and is concavely curved to a radius of curvature (L) of about one-half the wavelength, to stably support an object one-quarter wavelength (N) from the reflector.

  10. 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.

  11. 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.

  12. Acoustic integrated extinction

    PubMed Central

    Norris, Andrew N.

    2015-01-01

    The integrated extinction (IE) is defined as the integral of the scattering cross section as a function of wavelength. Sohl et al. (2007 J. Acoust. Soc. Am. 122, 3206–3210. (doi:10.1121/1.2801546)) derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here, we derive a formula for the acoustic IE that is valid for causal and non-causal scattering. The general result is expressed as an integral of the time-dependent forward scattering function. The IE reduces to a finite integral for scatterers with zero long-wavelength monopole and dipole amplitudes. Implications for acoustic cloaking are discussed and a new metric is proposed for broadband acoustic transparency. PMID:27547100

  13. Direct Field Acoustic Testing

    NASA Technical Reports Server (NTRS)

    Larkin, Paul; Goldstein, Bob

    2008-01-01

    This paper presents an update to the methods and procedures used in Direct Field Acoustic Testing (DFAT). The paper will discuss some of the recent techniques and developments that are currently being used and the future publication of a reference standard. Acoustic testing using commercial sound system components is becoming a popular and cost effective way of generating a required acoustic test environment both in and out of a reverberant chamber. This paper will present the DFAT test method, the usual setup and procedure and the development and use of a closed-loop, narrow-band control system. Narrow-band control of the acoustic PSD allows all standard techniques and procedures currently used in random control to be applied to acoustics and some examples are given. The paper will conclude with a summary of the development of a standard practice guideline that is hoped to be available in the first quarter of next year.

  14. 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.

  15. Acoustic wayfinding: A method to measure the acoustic contrast of different paving materials for blind people.

    PubMed

    Secchi, Simone; Lauria, Antonio; Cellai, Gianfranco

    2017-01-01

    Acoustic wayfinding involves using a variety of auditory cues to create a mental map of the surrounding environment. For blind people, these auditory cues become the primary substitute for visual information in order to understand the features of the spatial context and orient themselves. This can include creating sound waves, such as tapping a cane. This paper reports the results of a research about the "acoustic contrast" parameter between paving materials functioning as a cue and the surrounding or adjacent surface functioning as a background. A number of different materials was selected in order to create a test path and a procedure was defined for the verification of the ability of blind people to distinguish different acoustic contrasts. A method is proposed for measuring acoustic contrast generated by the impact of a cane tip on the ground to provide blind people with environmental information on spatial orientation and wayfinding in urban places.

  16. Distributed acoustic sensing with Michelson interferometer demodulation

    NASA Astrophysics Data System (ADS)

    Liu, Xiaohui; Wang, Chen; Shang, Ying; Wang, Chang; Zhao, Wenan; Peng, Gangding; Wang, Hongzhong

    2016-12-01

    The distributed acoustic sensing (DAS) has been extensively studied and widely used. A distributed acoustic sensing system based on the unbalanced Michelson interferometer with phase generated carrier (PGC) demodulation was designed and tested. The system could directly obtain the phase, amplitude, frequency response, and location information of sound wave at the same time and measurement at all points along the sensing fiber simultaneously. Experiments showed that the system successfully measured the acoustic signals with a phase-pressure sensitivity about-148 dB (re rad/μPa) and frequency response ripple less than 1.5 dB. The further field experiment showed that the system could measure signals at all points along the sensing fiber simultaneously.

  17. Particle Cloud Flames in Acoustic Fields

    NASA Technical Reports Server (NTRS)

    Berlad, A. L.; Tangirala, V.; Ross, H.; Facca, L.

    1990-01-01

    Results are presented on a study of flames supported by clouds of particles suspended in air, at pressures about 100 times lower than normal. In the experiment, an acoustic driver (4-in speaker) placed at one end of a closed tube, 0.75-m long and 0.05 m in diameter, disperses a cloud of lycopodium particles during a 0.5-sec powerful acoustic burst. Properties of the particle cloud and the flame were recorded by high-speed motion pictures and optical transmission detectors. Novel flame structures were observed, which owe their features to partial confinement, which encourages flame-acoustic interactions, segregation of particle clouds into laminae, and penetration of the flame's radiative flux density into the unburned particle-cloud regimes. Results of these experiments imply that, for particles in confined spaces, uncontrolled fire and explosion may be a threat even if the Phi(0) values are below some apparent lean limit.

  18. Considerations on the acoustic energy radiated by toothed gears. [model for calculating noise intensity

    NASA Technical Reports Server (NTRS)

    Popinceanu, N. G.; Kremmer, I.

    1974-01-01

    A mechano-acoustic model is reported for calculating acoustic energy radiated by a working gear. According to this model, a gear is an acoustic coublet formed of the two wheels. The wheel teeth generate cylindrical acoustic waves while the front surfaces of the teeth behave like vibrating pistons. Theoretical results are checked experimentally and good agreement is obtained with open gears. The experiments show that the air noise effect is negligible as compared with the structural noise transmitted to the gear box.

  19. Comparison of multi-microphone transfer matrix measurements with acoustic network models of swirl burners

    NASA Astrophysics Data System (ADS)

    Fischer, A.; Hirsch, C.; Sattelmayer, T.

    2006-11-01

    Utilizing the close analogy between electronic circuits and ducted acoustic systems, mathematical methods originally developed for the characterization of electronic networks are applied to the experimental acoustic plane wave characterization of swirl burners with complex geometries. The experiments presented in the paper show that the acoustic behavior of swirl generators can be quantitatively evaluated treating them as acoustic two-ports. Such acoustic two-ports are presented in forms of transfer-, scattering- and mobility matrices of the element. In the acoustic burner study dynamic pressure measurements were made at several locations of a tubular combustor test rig for two acoustically independent states, which were generated by forcing with sirens at the opposite ends of the setup. The technique for the experimental evaluation of acoustic transfer matrices of complex geometries on the basis of these dynamic pressure measurements is illustrated. As an alternative to the experiment, the evaluation of the acoustic behavior of acoustic systems is assessed using acoustic networks consisting of simple acoustic elements like ducts, bends, junctions and sudden area changes with transfer matrices, which are derived from first principles. In the paper, a network model representing the transfer characteristics of swirl burners is presented and compared with the previously measured transfer matrices. Although the burner geometry is rather complex, its acoustic behavior can be successfully mapped to a network consisting of a serial connection of nine elements with only minor adjustment of one parameter.

  20. Impulse source versus dodecahedral loudspeaker for measuring parameters derived from the impulse response in room acoustics.

    PubMed

    San Martín, Ricardo; Arana, Miguel; Machín, Jorge; Arregui, Abel

    2013-07-01

    This study investigates the performance of dodecahedral and impulse sources when measuring acoustic parameters in enclosures according to ISO 3382-1 [Acoustics-Measurement of room acoustic parameters. Part 1: Performance spaces (International Organization for Standardization, Geneva, Switzerland, 2009)]. In general, methods using speakers as a sound source are limited by their frequency response and directivity. On the other hand, getting impulse responses from impulse sources typically involves a lack of repeatability, and it is usually necessary to average several measurements for each position. Through experiments in different auditoriums that recreate typical situations in which the measurement standard is applied, it is found that using impulse sources leads to greater variation in the results, especially at low frequencies. However, this prevents subsequent dispersions due to variables that this technique does not require, such as the orientation of the emitting source. These dispersions may be relevant at high frequencies exceeding the established tolerance criteria for certain parameters. Finally, a new descriptor for dodecahedral sources reflecting the influence their lack of omnidirectionality produces on measuring acoustic parameters is proposed.

  1. Perceptual integration of acoustic cues to laryngeal contrasts in Korean fricatives.

    PubMed

    Lee, Sarah; Katz, Jonah

    2016-02-01

    This paper provides evidence that multiple acoustic cues involving the presence of low-frequency energy integrate in the perception of Korean coronal fricatives. This finding helps explain a surprising asymmetry between the production and perception of these fricatives found in previous studies: lower F0 onset in the following vowel leads to a response bias for plain [s] over fortis [s*], despite the fact that there is no evidence for a corresponding acoustic asymmetry in the production of [s] and [s*]. A fixed classification task using the Garner paradigm provides evidence that low F0 in a following vowel and the presence of voicing during frication perceptually integrate. This suggests that Korean listeners in previous experiments were responding to an "intermediate perceptual property" of stimuli, despite the fact that the individual acoustic components of that property are not all present in typical Korean fricative productions. The finding also broadens empirical support for the general idea of perceptual integration to a language, a different manner of consonant, and a situation where covariance of the acoustic cues under investigation is not generally present in a listener's linguistic input.

  2. Representation of concurrent acoustic objects in primary auditory cortex

    NASA Astrophysics Data System (ADS)

    Dyson, Benjamin J.; Alain, Claude

    2004-01-01

    Auditory scene analysis involves the simultaneous grouping and parsing of acoustic data into separate mental representations (i.e., objects). Over two experiments, we examined the sequence of neural processes underlying concurrent sound segregation by means of recording of human middle latency auditory evoked responses. Participants were presented with complex sounds comprising several harmonics, one of which could be mistuned such that it was not an integer multiple of the fundamental frequency. In both experiments, Na (approximately 22 ms) and Pa (approximately 32 ms) waves were reliably generated for all classes of stimuli. For stimuli with a fundamental frequency of 200 Hz, the mean Pa amplitude was significantly larger when the third harmonic was mistuned by 16% of its original value, relative to when it was tuned. The enhanced Pa amplitude was related to an increased likelihood in reporting the presence of concurrent auditory objects. Our results are consistent with a low-level stage of auditory scene analysis in which acoustic properties such as mistuning act as preattentive segregation cues that can subsequently lead to the perception of multiple auditory objects.

  3. 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.

  4. Acoustic scattering on spheroidal shapes near boundaries

    NASA Astrophysics Data System (ADS)

    Miloh, Touvia

    2016-11-01

    A new expression for the Lamé product of prolate spheroidal wave functions is presented in terms of a distribution of multipoles along the axis of the spheroid between its foci (generalizing a corresponding theorem for spheroidal harmonics). Such an "ultimate" singularity system can be effectively used for solving various linear boundary-value problems governed by the Helmholtz equation involving prolate spheroidal bodies near planar or other boundaries. The general methodology is formally demonstrated for the axisymmetric acoustic scattering problem of a rigid (hard) spheroid placed near a hard/soft wall or inside a cylindrical duct under an axial incidence of a plane acoustic wave.

  5. The Production and Recognition of Acoustic Frequency Cues in Chickadees

    NASA Astrophysics Data System (ADS)

    Lohr, Bernard Stephen

    1995-01-01

    The production and recognition of songs with appropriate species-typical features underlies a songbird's success in defending a breeding territory. The ability to recognize a song that is characteristic of one's own species presents an interesting problem, given the variety of types of information often encoded in song. Information in song may involve cues for individual identity, neighbor/stranger recognition, reproductive status, and motivational state. This thesis is concerned with the use of acoustic frequency as a cue for species-recognition of birdsong, and the various forms of frequency production and perception that may provide such cues. Carolina chickadees (Parus carolinensis) sing songs characterized by a succession of unmodulated, pure -tonal notes that alternate between high (approximately 5400-7000 Hz) and low (approximately 3000-4200 Hz) frequencies. Mechanisms of acoustic frequency perception in male territorial Carolina chickadees were evaluated using playback experiments designed to vary specific note frequencies, note frequency ranges, and the frequency range of the entire song type. Note frequency ranges provide the primary acoustic frequency cues for song recognition in this species. A gap between note frequency ranges exists in this species. Tones in this intermediate frequency range do not receive responses in the context of territorial song recognition. This kind of gap in frequency perception has not been demonstrated for other songbirds. Song playback experiments also were designed to vary systematically the contours (inter-note frequency sequences) of notes in song. Note frequency ranges provide the principal cues for song recognition, while the contour between note frequencies plays a supplementary role. The presence of a single descending interval between notes in the appropriate note frequency ranges of Carolina chickadee song generates full species-typical responses to song. Additionally, response to a descending contour between note

  6. Acoustic cooling engine

    DOEpatents

    Hofler, Thomas J.; Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1988-01-01

    An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element. The hot heat exchanger conducts heat from the first end to portions of the resonant pressure vessel proximate the hot heat exchanger. The hot heat exchanger permits substantial flow of the fluid through the hot heat exchanger. The resonant pressure vessel can include a housing less than one quarter wavelength in length coupled to a reservoir. The housing can include a reduced diameter portion communicating with the reservoir. The frequency of the acoustic driver can be continuously controlled so as to maintain resonance.

  7. Acoustic sniper localization system

    NASA Astrophysics Data System (ADS)

    Prado, Gervasio; Dhaliwal, Hardave; Martel, Philip O.

    1997-02-01

    Technologies for sniper localization have received increased attention in recent months as American forces have been deployed to various trouble spots around the world. Among the technologies considered for this task acoustics is a natural choice for various reasons. The acoustic signatures of gunshots are loud and distinctive, making them easy to detect even in high noise background environments. Acoustics provides a passive sensing technology with excellent range and non line of sight capabilities. Last but not least, an acoustic sniper location system can be built at a low cost with off the shelf components. Despite its many advantages, the performance of acoustic sensors can degrade under adverse propagation conditions. Localization accuracy, although good, is usually not accurate enough to pinpoint a sniper's location in some scenarios (for example which widow in a building or behind which tree in a grove). For these more demanding missions, the acoustic sensor can be used in conjunction with an infra red imaging system that detects the muzzle blast of the gun. The acoustic system can be used to cue the pointing system of the IR camera in the direction of the shot's source.

  8. Nonlinear acoustic fields in acoustic metamaterial based on a cylindrical pipe with periodically arranged side holes.

    PubMed

    Fan, Li; Ge, Huan; Zhang, Shu-yi; Gao, Hai-fei; Liu, Yong-hui; Zhang, Hui

    2013-06-01

    Nonlinear acoustic fields in transmission-line acoustic metamaterials based on a cylindrical pipe with periodically arranged side holes are studied, in which the dispersions and characteristic parameters of the nonlinear acoustic waves are obtained with the Bloch theory, and meanwhile the distributions of the fundamental wave (FW) and second harmonic wave (SHW) in the metamaterial are simulated. Three characteristic frequency bands are defined according to the relations between the frequencies of the FW, SHW, and the low-frequency forbidden band (LFB) in the metamaterial. Especially, when the FW is in the LFB while the SHW is outside the LFB, the SHW can transmit through the metamaterial although the FW is blocked, which exhibits the possibility to extract the information from the SHW instead of the FW. In addition, experiments are carried out to measure the distributions of the acoustic pressures for the FW and SHW along the metamaterial and the experimental results are in agreement with the theory.

  9. The acoustic monopole in motion

    NASA Technical Reports Server (NTRS)

    Norum, T. D.; Liu, C. H.

    1976-01-01

    The results of an experiment are presented in which a small monochromatic source which behaves like an acoustic monopole when stationary is moved at a constant speed over an asphalt surface past stationary microphones. An analysis of the monopole moving above a finite impedance reflecting plane is given. The theoretical and experimental results are compared for different ground to observer heights, source frequencies, and source velocities. A computation of the effects of source acceleration on the noise radiated by the monopole is also presented.

  10. The room acoustic rendering equation.

    PubMed

    Siltanen, Samuel; Lokki, Tapio; Kiminki, Sami; Savioja, Lauri

    2007-09-01

    An integral equation generalizing a variety of known geometrical room acoustics modeling algorithms is presented. The formulation of the room acoustic rendering equation is adopted from computer graphics. Based on the room acoustic rendering equation, an acoustic radiance transfer method, which can handle both diffuse and nondiffuse reflections, is derived. In a case study, the method is used to predict several acoustic parameters of a room model. The results are compared to measured data of the actual room and to the results given by other acoustics prediction software. It is concluded that the method can predict most acoustic parameters reliably and provides results as accurate as current commercial room acoustic prediction software. Although the presented acoustic radiance transfer method relies on geometrical acoustics, it can be extended to model diffraction and transmission through materials in future.

  11. 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.

  12. Acoustic well cleaner

    DOEpatents

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

    1997-01-21

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

  13. Acoustical heat pumping engine

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1983-08-16

    The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium.

  14. Acoustical heat pumping engine

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1983-08-16

    The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium. 2 figs.

  15. Magneto-acoustic imaging by continuous-wave excitation.

    PubMed

    Shunqi, Zhang; Zhou, Xiaoqing; Tao, Yin; Zhipeng, Liu

    2017-04-01

    The electrical characteristics of tissue yield valuable information for early diagnosis of pathological changes. Magneto-acoustic imaging is a functional approach for imaging of electrical conductivity. This study proposes a continuous-wave magneto-acoustic imaging method. A kHz-range continuous signal with an amplitude range of several volts is used to excite the magneto-acoustic signal and improve the signal-to-noise ratio. The magneto-acoustic signal amplitude and phase are measured to locate the acoustic source via lock-in technology. An optimisation algorithm incorporating nonlinear equations is used to reconstruct the magneto-acoustic source distribution based on the measured amplitude and phase at various frequencies. Validation simulations and experiments were performed in pork samples. The experimental and simulation results agreed well. While the excitation current was reduced to 10 mA, the acoustic signal magnitude increased up to 10(-7) Pa. Experimental reconstruction of the pork tissue showed that the image resolution reached mm levels when the excitation signal was in the kHz range. The signal-to-noise ratio of the detected magneto-acoustic signal was improved by more than 25 dB at 5 kHz when compared to classical 1 MHz pulse excitation. The results reported here will aid further research into magneto-acoustic generation mechanisms and internal tissue conductivity imaging.

  16. Imaging of Acoustic Waves in Sand

    SciTech Connect

    Deason, Vance Albert; Telschow, Kenneth Louis; Watson, Scott Marshall

    2003-08-01

    There is considerable interest in detecting objects such as landmines shallowly buried in loose earth or sand. Various techniques involving microwave, acoustic, thermal and magnetic sensors have been used to detect such objects. Acoustic and microwave sensors have shown promise, especially if used together. In most cases, the sensor package is scanned over an area to eventually build up an image or map of anomalies. We are proposing an alternate, acoustic method that directly provides an image of acoustic waves in sand or soil, and their interaction with buried objects. The INEEL Laser Ultrasonic Camera utilizes dynamic holography within photorefractive recording materials. This permits one to image and demodulate acoustic waves on surfaces in real time, without scanning. A video image is produced where intensity is directly and linearly proportional to surface motion. Both specular and diffusely reflecting surfaces can be accomodated and surface motion as small as 0.1 nm can be quantitatively detected. This system was used to directly image acoustic surface waves in sand as well as in solid objects. Waves as frequencies of 16 kHz were generated using modified acoustic speakers. These waves were directed through sand toward partially buried objects. The sand container was not on a vibration isolation table, but sat on the lab floor. Interaction of wavefronts with buried objects showed reflection, diffraction and interference effects that could provide clues to location and characteristics of buried objects. Although results are preliminary, success in this effort suggests that this method could be applied to detection of buried landmines or other near-surface items such as pipes and tanks.

  17. Can biophysics tell us something about the weak equivalence principle vis a vis the thought experiment of Einstein involving human subjects?

    PubMed

    Thaheld, Fred H

    2009-08-01

    Over a period of several decades it has been noticed that most astronauts, either orbiting the earth or on trips to the moon, have observed phosphenes or light flashes (LF) including streaks, spots and clouds of light when their eyes are closed or they are in a darkened cabin. Scientists suspect that two separate components of cosmic rays cause these flashes due to direct interaction with the retina. This phenomenon is not noticed on the ground because of cosmic ray interaction with the atmosphere. The argument is advanced that this effect may provide us with a new method of exploring the weak equivalence principle from the standpoint of Einstein's original thought experiment involving human subjects. This can be done, utilizing the retina only, as an animate quantum mechanical measuring device or, in conjunction with the Anomalous Long Term Effects on Astronauts (ALTEA) facility.

  18. A Descriptive and Explorative Case Study of a Scratch Programming Experience Involving the Creation of a Lunar Simulation/Model with Grade Six Learners

    NASA Astrophysics Data System (ADS)

    Martin, Stephen Alexander

    This mixed methods descriptive and exploratory case study examined the experiences of two classes in an elementary school (39 students) using the Scratch programming language to create a lunar simulation of the Earth/Moon System over six days. Using the Computational Thinking Framework developed by Brennan and Resnick (2012) the researcher examined the computational thinking (CT) concepts and practices students were exposed to. This study finds that all of the student groups experienced at least partial success in building their simulation. The researcher found that all of the groups explored the CT concepts of sequence, events, parallelism, conditionals and operators while building their simulation and more than 80% of the groups used data and loops. There is evidence that the students were involved in three of the computational practices: incremental and iterative, testing and debugging and, abstracting and modularizing. This study offers recommendations for practice and for future research.

  19. a Numerical Model for Subsonic Acoustic Choking.

    NASA Astrophysics Data System (ADS)

    Walkington, Noel John

    In aircraft turbofan inlets, fan generated noise is observed experimentally to be significantly attenuated at high subsonic inlet Mach numbers. This phenomenon cannot be predicted by linear acoustic theory. In order to study the physical process by which this may occur, a numerical algorithm has been developed to solve a related nonlinear problem in one dimensional gas dynamics. The nonlinear solution admits the possibility of wave steepening and shock waves. Approximate solutions are obtained using several finite difference schemes. The boundary conditions required to model an acoustic source and an anechoic termination are developed. The numerical solutions agree closely with those obtained using the method of matched asymptotic expansions. Solutions involving shock waves exhibit a large reduction in the ratio of transmitted to incident power. This offers an explanation for acoustic choking. The results indicate that more power is dissipated as the Mach number, sound amplitude and frequency are increased. These observations are in agreement with those observed experimentally.

  20. Advances in Geometric Acoustic Propagation Modeling Methods

    NASA Astrophysics Data System (ADS)

    Blom, P. S.; Arrowsmith, S.

    2013-12-01

    Geometric acoustics provides an efficient numerical method to model propagation effects. At leading order, one can identify ensonified regions and calculate celerities of the predicted arrivals. Beyond leading order, the solution of the transport equation provides a means to estimate the amplitude of individual acoustic phases. The auxiliary parameters introduced in solving the transport equation have been found to provide a means of identifying ray paths connecting source and receiver, or eigenrays, for non-planar propagation. A detailed explanation of the eigenray method will be presented as well as an application to predicting azimuth deviations for infrasonic data recorded during the Humming Roadrunner experiment of 2012.

  1. Omnidirectional broadband acoustic deflector based on metamaterials

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Liang, Bin; Zou, Xin-ye; Yang, Jing; Yang, Jun; Cheng, Jian-chun

    2017-02-01

    We report a theoretical, numerical, and experimental work on the design of an omnidirectional acoustic deflector capable of redirecting an incident wave to propagate along a predesigned direction over a broad frequency range, regardless of the incidence angle. An implementation by metamaterials is demonstrated both in simulation and experiment, with both showing the effectiveness of our scheme as long as the effective medium approximation stands. With the capability of omnidirectional broadband deflection and the flexibility of a controllable tuning angle, our design opens a route to the development of wave-steering devices and has great application potentials in various situations such as on-chip acoustic manipulations.

  2. Acoustic imaging system

    DOEpatents

    Smith, Richard W.

    1979-01-01

    An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

  3. Compact acoustic refrigerator

    SciTech Connect

    Bennett, G.A.

    1991-12-31

    This invention is comprised of a compact acoustic refrigeration system that actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment.

  4. Acoustic borehole logging

    SciTech Connect

    Medlin, W.L.; Manzi, S.J.

    1990-10-09

    This patent describes an acoustic borehole logging method. It comprises traversing a borehole with a borehole logging tool containing a transmitter of acoustic energy having a free-field frequency spectrum with at least one characteristic resonant frequency of vibration and spaced-apart receiver, repeatedly exciting the transmitter with a swept frequency tone burst of a duration sufficiently greater than the travel time of acoustic energy between the transmitter and the receiver to allow borehole cavity resonances to be established within the borehole cavity formed between the borehole logging tool and the borehole wall, detecting acoustic energy amplitude modulated by the borehole cavity resonances with the spaced-apart receiver, and recording an amplitude verses frequency output of the receiver in correlation with depth as a log of the borehole frequency spectrum representative of the subsurface formation comprising the borehole wall.

  5. Acoustic imaging system

    NASA Technical Reports Server (NTRS)

    Kendall, J. M., Jr.

    1977-01-01

    Tool detects noise sources by scanning sound "scene" and displaying relative location of noise-producing elements in area. System consists of ellipsoidal acoustic mirror and microphone and a display device.

  6. Compact acoustic refrigerator

    DOEpatents

    Bennett, G.A.

    1992-11-24

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.

  7. Compact acoustic refrigerator

    DOEpatents

    Bennett, Gloria A.

    1992-01-01

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.

  8. Acoustic bubble traps

    NASA Astrophysics Data System (ADS)

    Geisler, Reinhard; Kurz, Thomas; Lauterborn, Werner

    2000-07-01

    A small, oscillating bubble in a liquid can be trapped in the antinode of an acoustic standing wave field. Bubble stability is required for the study of single bubble sonoluminescence (SBSL). The properties of the acoustic resonator are essential for the stable trapping of sonoluminescing bubbles. Resonators can be chosen according to the intended application: size and geometry can be varied in a wide range. In this work, the acoustic responses of different resonators were measured by means of holographic interferometry, hydrophones and a laser vibrometer. Also, high-speed photography was used to observe the bubble dynamics. Several single, stable sonoluminescent bubbles were trapped simultaneously within an acoustic resonator in the pressure antinodes of a higher harmonic mode (few bubble sonoluminescence, FBSL).

  9. Department of Cybernetic Acoustics

    NASA Astrophysics Data System (ADS)

    The development of the theory, instrumentation and applications of methods and systems for the measurement, analysis, processing and synthesis of acoustic signals within the audio frequency range, particularly of the speech signal and the vibro-acoustic signal emitted by technical and industrial equipments treated as noise and vibration sources was discussed. The research work, both theoretical and experimental, aims at applications in various branches of science, and medicine, such as: acoustical diagnostics and phoniatric rehabilitation of pathological and postoperative states of the speech organ; bilateral ""man-machine'' speech communication based on the analysis, recognition and synthesis of the speech signal; vibro-acoustical diagnostics and continuous monitoring of the state of machines, technical equipments and technological processes.

  10. Basic Linear Acoustics

    NASA Astrophysics Data System (ADS)

    Pierce, Alan D.

    This chapter deals with the physical and mathematical aspects of sound when the disturbances are, in some sense, small. Acoustics is usually concerned with small-amplitude phenomena, and consequently a linear description is usually acoustics applicable. Disturbances are governed by the properties of the medium in which they occur, and the governing equations are the equations of continuum mechanics, which apply equally to gases, liquids, and solids. These include the mass, momentum, and energy equations, as well as thermodynamic principles. The viscosity and thermal conduction enter into the versions of these equations that apply to fluids. Fluids of typical great interest are air and sea water, and consequently this chapter includes a summary of their relevant acoustic properties. The foundation is also laid for the consideration of acoustic waves in elastic solids, suspensions, bubbly liquids, and porous media.

  11. Acoustics lecturing in Mexico

    NASA Astrophysics Data System (ADS)

    Beristain, Sergio

    2002-11-01

    Some thirty years ago acoustics lecturing started in Mexico at the National Polytechnic Institute in Mexico City, as part of the Bachelor of Science degree in Communications and Electronics Engineering curricula, including the widest program on this field in the whole country. This program has been producing acoustics specialists ever since. Nowadays many universities and superior education institutions around the country are teaching students at the B.Sc. level and postgraduate level many topics related to acoustics, such as Architectural Acoustics, Seismology, Mechanical Vibrations, Noise Control, Audio, Audiology, Music, etc. Also many institutions have started research programs in related fields, with participation of medical doctors, psychologists, musicians, engineers, etc. Details will be given on particular topics and development.

  12. Acoustic Neuroma Association

    MedlinePlus

    ... this sponsor... Platinum Sponsor More from this sponsor... Gold Sponsor University of Colorado Acoustic Neuroma Program Rocky Mountain Gamma Knife Center More from this sponsor... Gold Sponsor NYU Langone Medical Center Departments of Neurosurgery ...

  13. Development of a MEMS acoustic emission sensor system

    NASA Astrophysics Data System (ADS)

    Greve, David W.; Oppenheim, Irving J.; Wu, Wei; Wright, Amelia P.

    2007-04-01

    An improved multi-channel MEMS chip for acoustic emission sensing has been designed and fabricated in 2006 to create a device that is smaller in size, superior in sensitivity, and more practical to manufacture than earlier designs. The device, fabricated in the MUMPS process, contains four resonant-type capacitive transducers in the frequency range between 100 kHz and 500 kHz on a chip with an area smaller than 2.5 sq. mm. The completed device, with its circuit board, electronics, housing, and connectors, possesses a square footprint measuring 25 mm x 25 mm. The small footprint is an important attribute for an acoustic emission sensor, because multiple sensors must typically be arrayed around a crack location. Superior sensitivity was achieved by a combination of four factors: the reduction of squeeze film damping, a resonant frequency approximating a rigid body mode rather than a bending mode, a ceramic package providing direct acoustic coupling to the structural medium, and high-gain amplifiers implemented on a small circuit board. Manufacture of the system is more practical because of higher yield (lower unit costs) in the MUMPS fabrication task and because of a printed circuit board matching the pin array of the MEMS chip ceramic package for easy assembly and compactness. The transducers on the MEMS chip incorporate two major mechanical improvements, one involving squeeze film damping and one involving the separation of resonance modes. For equal proportions of hole area to plate area, a triangular layout of etch holes reduces squeeze film damping as compared to the conventional square layout. The effect is modeled analytically, and is verified experimentally by characterization experiments on the new transducers. Structurally, the transducers are plates with spring supports; a rigid plate would be the most sensitive transducer, and bending decreases the sensitivity. In this chip, the structure was designed for an order-of-magnitude separation between the first

  14. 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.

  15. 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.

  16. Effects of intra-prelimbic prefrontal cortex injection of cannabidiol on anxiety-like behavior: involvement of 5HT1A receptors and previous stressful experience.

    PubMed

    Fogaça, M V; Reis, F M C V; Campos, A C; Guimarães, F S

    2014-03-01

    The prelimbic medial prefrontal cortex (PL) is an important encephalic structure involved in the expression of emotional states. In a previous study, intra-PL injection of cannabidiol (CBD), a major non-psychotomimetic cannabinoid present in the Cannabis sativa plant, reduced the expression of fear conditioning response. Although its mechanism remains unclear, CBD can facilitate 5HT1A receptor-mediated neurotransmission when injected into several brain structures. This study was aimed at verifying if intra-PL CBD could also induce anxiolytic-like effect in a conceptually distinct animal model, the elevated plus maze (EPM). We also verified if CBD effects in the EPM and contextual fear conditioning test (CFC) depend on 5HT1A receptors and previous stressful experience. CBD induced opposite effects in the CFC and EPM, being anxiolytic and anxiogenic, respectively. Both responses were prevented by WAY100,635, a 5HT1A receptor antagonist. In animals that had been previously (24h) submitted to a stressful event (2h-restraint) CBD caused an anxiolytic, rather than anxiogenic, effect in the EPM. This anxiolytic response was abolished by previous injection of metyrapone, a glucocorticoid synthesis blocker. Moreover, restraint stress increased 5HT1A receptors expression in the dorsal raphe nucleus, an effect that was attenuated by injection of metyrapone before the restraint procedure. Taken together, these results suggest that CBD modulation of anxiety in the PL depend on 5HT1A-mediated neurotransmission and previous stressful experience.

  17. Anisotropic Swirling Surface Acoustic Waves from Inverse Filtering for On-Chip Generation of Acoustic Vortices

    NASA Astrophysics Data System (ADS)

    Riaud, Antoine; Thomas, Jean-Louis; Charron, Eric; Bussonnière, Adrien; Bou Matar, Olivier; Baudoin, Michael

    2015-09-01

    From radio-electronics signal analysis to biological sample actuation, surface acoustic waves (SAWs) are involved in a multitude of modern devices. However, only the most simple standing or progressive waves such as plane and focused waves have been explored so far. In this paper, we expand the SAW toolbox with a wave family named "swirling surface acoustic waves" which are the 2D anisotropic analogue of bulk acoustic vortices. Similarly to their 3D counterpart, they appear as concentric structures of bright rings with a phase singularity in their center resulting in a central dark spot. After the rigorous mathematical definition of these waves, we synthesize them experimentally through the inverse filtering technique revisited for surface waves. For this purpose, we design a setup combining arrays of interdigitated transducers and a multichannel electronic that enables one to synthesize any prescribed wave field compatible with the anisotropy of the substrate in a region called the "acoustic scene." This work opens prospects for the design of integrated acoustic vortex generators for on-chip selective acoustic tweezing.

  18. Numerical Techniques in Acoustics

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J. (Compiler)

    1985-01-01

    This is the compilation of abstracts of the Numerical Techniques in Acoustics Forum held at the ASME's Winter Annual Meeting. This forum was for informal presentation and information exchange of ongoing acoustic work in finite elements, finite difference, boundary elements and other numerical approaches. As part of this forum, it was intended to allow the participants time to raise questions on unresolved problems and to generate discussions on possible approaches and methods of solution.

  19. The neonatal acoustic reflex.

    PubMed

    Weatherby, L A; Bennett, M J

    1980-01-01

    Probe tones from 220 Hz to 2 000 Hz were used to measure the static and dynamic acoustic impedance of 44 neonates. Acoustic reflex thresholds to broad band noise were obtained from every neonate tested when employing the higher frequency probe tones. The reflex threshold levels measured are similar to those of adults. The static impedance values are discussed to give a possible explanation of why reflex thresholds cannot be detected using conventional 220 Hz impedance bridges.

  20. Directional Acoustic Density Sensor

    DTIC Science & Technology

    2010-09-13

    fluctuations of fluid density at a point . (2) DESCRIPTION OF THE PRIOR ART [0004] Conventional vector sensors measure particle velocity, v (vx,Vytvz...dipole-type or first order sensor that is realized by measuring particle velocity at a point , (which is the vector sensor sensing approach for...underwater sensors), or by measuring the gradient of the acoustic pressure at two closely spaced (less than the wavelength of an acoustic wave) points as it

  1. Low Frequency Acoustics

    DTIC Science & Technology

    2016-06-13

    with NOAA , ONR is providing technical services that will help establish a baseline for assessment of long- term VLF acoustic trends in selected...ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 sponsored by NOAA , was added to the...with NOAA (NMFS) and other parties has dealt with ocean acoustics related to issues stimulated by the Marine Mammal Protection Act. A focal point has

  2. Ecological Insights from Pelagic Habitats Acquired Using Active Acoustic Techniques

    NASA Astrophysics Data System (ADS)

    Benoit-Bird, Kelly J.; Lawson, Gareth L.

    2016-01-01

    Marine pelagic ecosystems present fascinating opportunities for ecological investigation but pose important methodological challenges for sampling. Active acoustic techniques involve producing sound and receiving signals from organisms and other water column sources, offering the benefit of high spatial and temporal resolution and, via integration into different platforms, the ability to make measurements spanning a range of spatial and temporal scales. As a consequence, a variety of questions concerning the ecology of pelagic systems lend themselves to active acoustics, ranging from organism-level investigations and physiological responses to the environment to ecosystem-level studies and climate. As technologies and data analysis methods have matured, the use of acoustics in ecological studies has grown rapidly. We explore the continued role of active acoustics in addressing questions concerning life in the ocean, highlight creative applications to key ecological themes ranging from physiology and behavior to biogeography and climate, and discuss emerging avenues where acoustics can help determine how pelagic ecosystems function.

  3. Ecological Insights from Pelagic Habitats Acquired Using Active Acoustic Techniques.

    PubMed

    Benoit-Bird, Kelly J; Lawson, Gareth L

    2016-01-01

    Marine pelagic ecosystems present fascinating opportunities for ecological investigation but pose important methodological challenges for sampling. Active acoustic techniques involve producing sound and receiving signals from organisms and other water column sources, offering the benefit of high spatial and temporal resolution and, via integration into different platforms, the ability to make measurements spanning a range of spatial and temporal scales. As a consequence, a variety of questions concerning the ecology of pelagic systems lend themselves to active acoustics, ranging from organism-level investigations and physiological responses to the environment to ecosystem-level studies and climate. As technologies and data analysis methods have matured, the use of acoustics in ecological studies has grown rapidly. We explore the continued role of active acoustics in addressing questions concerning life in the ocean, highlight creative applications to key ecological themes ranging from physiology and behavior to biogeography and climate, and discuss emerging avenues where acoustics can help determine how pelagic ecosystems function.

  4. Squaring Up: Experiences of Transition from Off-Street Sex Work to Square Work and Duality--Concurrent Involvement in Both--in Vancouver, BC.

    PubMed

    Bowen, Raven R

    2015-11-01

    Many studies of exit from sex work are inspired by role theory, where people experience a lack of attachment to a role; are faced with individual, interactional, and structural challenges; contemplate transition and exit a role; and then struggle to establish postrole identities and new lives. This framework has been used to explicate the factors and experiences of those who leave or attempt to leave the sex industry; however, it is limited because studies present sex work as a harmful and dangerous profession that people are trapped in, escaping, or have survived. In this paper, I discuss Vancouver's history of violence against sex workers and I review research on sex work exiting and bring forward recommendations for the design of exit program based on the experiences of 22 active and former off-street sex workers from Vancouver, British Columbia. I describe study participants who include Sex-Work-No-More participants who would not return to the industry, Sex-Work-Maybe participants who consider reinvolvement, and Dual-Life participants who are employed in sex work and conventional work simultaneously. These participants uniquely challenge narrow, binary understandings of involvement and transition because they discuss their use of deception to obtain resources needed to make change; the support that clients have provided; their strategic engagement in sex work as a means to exit; their considerations of reentry; and for some, their dual employment. In light of new legislation that criminalizes activities related to sex work-the Protection of Communities and Exploited Persons Act-and the Federal government announcement of $20 million dollars for the creation of exit services nationwide, hearing from sex workers is essential to advancing agendas in this area.

  5. Influence of Acoustic Overstimulation on the Central Auditory System: An Functional Magnetic Resonance Imaging (fMRI) Study.

    PubMed

    Wolak, Tomasz; Cieśla, Katarzyna; Rusiniak, Mateusz; Piłka, Adam; Lewandowska, Monika; Pluta, Agnieszka; Skarżyński, Henryk; Skarżyński, Piotr H

    2016-11-28

    BACKGROUND The goal of the fMRI experiment was to explore the involvement of central auditory structures in pathomechanisms of a behaviorally manifested auditory temporary threshold shift in humans. MATERIAL AND METHODS The material included 18 healthy volunteers with normal hearing. Subjects in the exposure group were presented with 15 min of binaural acoustic overstimulation of narrowband noise (3 kHz central frequency) at 95 dB(A). The control group was not exposed to noise but instead relaxed in silence. Auditory fMRI was performed in 1 session before and 3 sessions after acoustic overstimulation and involved 3.5-4.5 kHz sweeps. RESULTS The outcomes of the study indicate a possible effect of acoustic overstimulation on central processing, with decreased brain responses to auditory stimulation up to 20 min after exposure to noise. The effect can be seen already in the primary auditory cortex. Decreased BOLD signal change can be due to increased excitation thresholds and/or increased spontaneous activity of auditory neurons throughout the auditory system. CONCLUSIONS The trial shows that fMRI can be a valuable tool in acoustic overstimulation studies but has to be used with caution and considered complimentary to audiological measures. Further methodological improvements are needed to distinguish the effects of TTS and neuronal habituation to repetitive stimulation.

  6. Influence of Acoustic Overstimulation on the Central Auditory System: An Functional Magnetic Resonance Imaging (fMRI) Study

    PubMed Central

    Wolak, Tomasz; Cieśla, Katarzyna; Rusiniak, Mateusz; Piłka, Adam; Lewandowska, Monika; Pluta, Agnieszka; Skarżyński, Henryk; Skarżyński, Piotr H.

    2016-01-01

    Background The goal of the fMRI experiment was to explore the involvement of central auditory structures in pathomechanisms of a behaviorally manifested auditory temporary threshold shift in humans. Material/Methods The material included 18 healthy volunteers with normal hearing. Subjects in the exposure group were presented with 15 min of binaural acoustic overstimulation of narrowband noise (3 kHz central frequency) at 95 dB(A). The control group was not exposed to noise but instead relaxed in silence. Auditory fMRI was performed in 1 session before and 3 sessions after acoustic overstimulation and involved 3.5–4.5 kHz sweeps. Results The outcomes of the study indicate a possible effect of acoustic overstimulation on central processing, with decreased brain responses to auditory stimulation up to 20 min after exposure to noise. The effect can be seen already in the primary auditory cortex. Decreased BOLD signal change can be due to increased excitation thresholds and/or increased spontaneous activity of auditory neurons throughout the auditory system. Conclusions The trial shows that fMRI can be a valuable tool in acoustic overstimulation studies but has to be used with caution and considered complimentary to audiological measures. Further methodological improvements are needed to distinguish the effects of TTS and neuronal habituation to repetitive stimulation. PMID:27893698

  7. Ocean acoustic reverberation tomography.

    PubMed

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography.

  8. Scaling and dimensional analysis of acoustic streaming jets

    NASA Astrophysics Data System (ADS)

    Moudjed, B.; Botton, V.; Henry, D.; Ben Hadid, H.; Garandet, J.-P.

    2014-09-01

    This paper focuses on acoustic streaming free jets. This is to say that progressive acoustic waves are used to generate a steady flow far from any wall. The derivation of the governing equations under the form of a nonlinear hydrodynamics problem coupled with an acoustic propagation problem is made on the basis of a time scale discrimination approach. This approach is preferred to the usually invoked amplitude perturbations expansion since it is consistent with experimental observations of acoustic streaming flows featuring hydrodynamic nonlinearities and turbulence. Experimental results obtained with a plane transducer in water are also presented together with a review of the former experimental investigations using similar configurations. A comparison of the shape of the acoustic field with the shape of the velocity field shows that diffraction is a key ingredient in the problem though it is rarely accounted for in the literature. A scaling analysis is made and leads to two scaling laws for the typical velocity level in acoustic streaming free jets; these are both observed in our setup and in former studies by other teams. We also perform a dimensional analysis of this problem: a set of seven dimensionless groups is required to describe a typical acoustic experiment. We find that a full similarity is usually not possible between two acoustic streaming experiments featuring different fluids. We then choose to relax the similarity with respect to sound attenuation and to focus on the case of a scaled water experiment representing an acoustic streaming application in liquid metals, in particular, in liquid silicon and in liquid sodium. We show that small acoustic powers can yield relatively high Reynolds numbers and velocity levels; this could be a virtue for heat and mass transfer applications, but a drawback for ultrasonic velocimetry.

  9. Scaling and dimensional analysis of acoustic streaming jets

    SciTech Connect

    Moudjed, B.; Botton, V.; Henry, D.; Ben Hadid, H.

    2014-09-15

    This paper focuses on acoustic streaming free jets. This is to say that progressive acoustic waves are used to generate a steady flow far from any wall. The derivation of the governing equations under the form of a nonlinear hydrodynamics problem coupled with an acoustic propagation problem is made on the basis of a time scale discrimination approach. This approach is preferred to the usually invoked amplitude perturbations expansion since it is consistent with experimental observations of acoustic streaming flows featuring hydrodynamic nonlinearities and turbulence. Experimental results obtained with a plane transducer in water are also presented together with a review of the former experimental investigations using similar configurations. A comparison of the shape of the acoustic field with the shape of the velocity field shows that diffraction is a key ingredient in the problem though it is rarely accounted for in the literature. A scaling analysis is made and leads to two scaling laws for the typical velocity level in acoustic streaming free jets; these are both observed in our setup and in former studies by other teams. We also perform a dimensional analysis of this problem: a set of seven dimensionless groups is required to describe a typical acoustic experiment. We find that a full similarity is usually not possible between two acoustic streaming experiments featuring different fluids. We then choose to relax the similarity with respect to sound attenuation and to focus on the case of a scaled water experiment representing an acoustic streaming application in liquid metals, in particular, in liquid silicon and in liquid sodium. We show that small acoustic powers can yield relatively high Reynolds numbers and velocity levels; this could be a virtue for heat and mass transfer applications, but a drawback for ultrasonic velocimetry.

  10. Perception of recorded singing voice quality and expertise: cognitive linguistics and acoustic approaches.

    PubMed

    Morange, Séverine; Dubois, Danièle; Fontaine, Jean-Marc

    2010-07-01

    The objective of the present pluridisciplinary study was to contribute to determine how a diversity of audience differently appreciates several versions resulting from different "restoration" treatments of one single original lyrical recording. We present here a joint analysis coupling psychological and linguistic analyses with acoustic descriptions on a unique research object: a Caruso's piece of song diversely remastered on commercial CDs. Thirty-two subjects were selected contrasted on age ("younger than 30 years" and "older than 60 years") related with their different experience of earlier technical recording devices (rendering through devices such as radio, 78rpm records, CD...) and on expertise concerning musical acoustics (acousticians and/or musicians vs ordinary music lovers). Eleven excerpts of reediting of an opera record interpreted by Caruso were selected from what could found on the market. The listening protocol involved a free categorization task and the selection of excerpts on preference judgments. Each task involved subjects' free commentaries about their choices as a joint output from psychological processing. A cluster analysis scaffold by a psycholinguistic processing of the verbal comments of the categories allowed to identify both commonalities and differences in groupings excerpts by the different groups of the subjects, along a diversity of criteria, varying according to age and expertise. Each excerpt can therefore be characterized both according to psychological and to acoustic criteria. This study has enabled us to develop the idea that a lyric voice is a multifaced object (cultural, esthetic, technical, physical), acoustic parameters being linked to the various sensory experiences and expertises of appraisers. Such pluridisciplinary research and the coupling of the correlated multiplicity of methodologies we developed acknowledge for a better understanding of listening practices and music-lover assessments here concerned with a

  11. Experiments with Ultrasonic Transducers.

    ERIC Educational Resources Information Center

    Greenslade, Thomas R., Jr.

    1994-01-01

    Discusses the use of 40 kHz ultrasonic transducers to study wave phenomena. Determines that the resulting wavelength of 9 mm allows acoustic experiments to be performed on a tabletop. Includes transducer characteristics and activities on speed of sound, reflection, double- and single-slit diffraction, standing waves, acoustical zone plate, and…

  12. The Japanese containerless experiments

    NASA Technical Reports Server (NTRS)

    Azuma, Hisao

    1990-01-01

    There are three sets of Japanese containerless experiments. The first is Drop dynamics research. It consists of acoustic levitation and large amplitude drop oscillation. The second is Optical materials processing in an acoustic levitation furnace. And the third is Electrostatic levitator development by two different Japanese companies.

  13. Acoustic and Categorical Dissimilarity of Musical Timbre: Evidence from Asymmetries Between Acoustic and Chimeric Sounds.

    PubMed

    Siedenburg, Kai; Jones-Mollerup, Kiray; McAdams, Stephen

    2015-01-01

    This paper investigates the role of acoustic and categorical information in timbre dissimilarity ratings. Using a Gammatone-filterbank-based sound transformation, we created tones that were rated as less familiar than recorded tones from orchestral instruments and that were harder to associate with an unambiguous sound source (Experiment 1). A subset of transformed tones, a set of orchestral recordings, and a mixed set were then rated on pairwise dissimilarity (Experiment 2A). We observed that recorded instrument timbres clustered into subsets that distinguished timbres according to acoustic and categorical properties. For the subset of cross-category comparisons in the mixed set, we observed asymmetries in the distribution of ratings, as well as a stark decay of inter-rater agreement. These effects were replicated in a more robust within-subjects design (Experiment 2B) and cannot be explained by acoustic factors alone. We finally introduced a novel model of timbre dissimilarity based on partial least-squares regression that compared the contributions of both acoustic and categorical timbre descriptors. The best model fit (R (2) = 0.88) was achieved when both types of descriptors were taken into account. These findings are interpreted as evidence for an interplay of acoustic and categorical information in timbre dissimilarity perception.

  14. Acoustic and Categorical Dissimilarity of Musical Timbre: Evidence from Asymmetries Between Acoustic and Chimeric Sounds

    PubMed Central

    Siedenburg, Kai; Jones-Mollerup, Kiray; McAdams, Stephen

    2016-01-01

    This paper investigates the role of acoustic and categorical information in timbre dissimilarity ratings. Using a Gammatone-filterbank-based sound transformation, we created tones that were rated as less familiar than recorded tones from orchestral instruments and that were harder to associate with an unambiguous sound source (Experiment 1). A subset of transformed tones, a set of orchestral recordings, and a mixed set were then rated on pairwise dissimilarity (Experiment 2A). We observed that recorded instrument timbres clustered into subsets that distinguished timbres according to acoustic and categorical properties. For the subset of cross-category comparisons in the mixed set, we observed asymmetries in the distribution of ratings, as well as a stark decay of inter-rater agreement. These effects were replicated in a more robust within-subjects design (Experiment 2B) and cannot be explained by acoustic factors alone. We finally introduced a novel model of timbre dissimilarity based on partial least-squares regression that compared the contributions of both acoustic and categorical timbre descriptors. The best model fit (R2 = 0.88) was achieved when both types of descriptors were taken into account. These findings are interpreted as evidence for an interplay of acoustic and categorical information in timbre dissimilarity perception. PMID:26779086

  15. Microparticle column geometry in acoustic stationary fields.

    PubMed

    Hancock, Andrew; Insana, Michael F; Allen, John S

    2003-01-01

    Particles suspended in a fluid will experience forces from stationary acoustic fields. The magnitude of the force depends on the time-averaged energy density of the field and the material properties of the particles and fluid. Forces acting on known particles smaller than 20 microm were studied. Within a 500 kHz acoustic beam generated by a plane-piston circular source, observations were made of the geometry of the particle column that is formed. Varying the acoustic energy altered the column width in a manner predicted by equations for the primary acoustic radiation force from scattering of particles in the long-wavelength limit. The minimum pressures required to trap gas, solid, and liquid particles in a water medium at room temperature were also estimated to within 12%. These results highlight the ability of stationary acoustic fields from a plane-piston radiator to impose nano-Newton-scale forces onto fluid particles with properties similar to biological cells, and suggest that it is possible to accurately quantify these forces.

  16. Virtual acoustic displays

    NASA Technical Reports Server (NTRS)

    Wenzel, Elizabeth M.

    1991-01-01

    A 3D auditory display can potentially enhance information transfer by combining directional and iconic information in a quite naturalistic representation of dynamic objects in the interface. Another aspect of auditory spatial clues is that, in conjunction with other modalities, it can act as a potentiator of information in the display. For example, visual and auditory cues together can reinforce the information content of the display and provide a greater sense of presence or realism in a manner not readily achievable by either modality alone. This phenomenon will be particularly useful in telepresence applications, such as advanced teleconferencing environments, shared electronic workspaces, and monitoring telerobotic activities in remote or hazardous situations. Thus, the combination of direct spatial cues with good principles of iconic design could provide an extremely powerful and information-rich display which is also quite easy to use. An alternative approach, recently developed at ARC, generates externalized, 3D sound cues over headphones in realtime using digital signal processing. Here, the synthesis technique involves the digital generation of stimuli using Head-Related Transfer Functions (HRTF's) measured in the two ear-canals of individual subjects. Other similar approaches include an analog system developed by Loomis, et. al., (1990) and digital systems which make use of transforms derived from normative mannikins and simulations of room acoustics. Such an interface also requires the careful psychophysical evaluation of listener's ability to accurately localize the virtual or synthetic sound sources. From an applied standpoint, measurement of each potential listener's HRTF's may not be possible in practice. For experienced listeners, localization performance was only slightly degraded compared to a subject's inherent ability. Alternatively, even inexperienced listeners may be able to adapt to a particular set of HRTF's as long as they provide adequate

  17. Data Management Techniques for Acoustical Planetary Data

    NASA Astrophysics Data System (ADS)

    Eichelberger, Hans; Prattes, Gustav; Schwingenschuh, Konrad; Tokano, T.; Jernej, I.; Stachel, Manfred; Besser, B. P.; Aydogar, Oe.

    We discuss data management techniques for acoustical data obtained from future atmospheric planetary in-situ probes with the aim of event oriented scientific analysis. The immediate objec-tive is the localisation (acoustic wave telescope) and characterisation of acoustic phenomena of atmospheres and surfaces, e.g. in the frame of the proposed NASA/ESA Titan Saturn System Mission (TSSM) with the Acoustic Sensor Package (ACU) multi-microphone array. Contrary to huge amounts of source data obtained through the electromagnetic windows, acoustical sig-nals are seldom recorded and few files exist. One example is pressure sensor data from the instrument HASI/PWA during Huygens descent, mission Cassini-Huygens. Nevertheless, a lot of acoustic point and noise sources, e.g. caused by rain, drizzle or wind abound in Titan's atmosphere. In almost all cases, due to limitations in telemetry rate, a careful strategy for onboard event handling and data reduction -the first step in data management -has to be selected, e.g. sampling rates in kHz range or averaging in the frequency domain. This pre-processing together with complementary investigations at the space segment directly influences the scientific data return in terms of long-term continuous or short-term event based studies. The database at the ground segment with science data and metadata entries after final calibra-tion has to support the combined investigations with other instruments. This second step in data management fully explores the acoustic environment of planetary atmospheres in terms of background noise and spacecraft generated disturbances, location and characterisation of source regions and correlation between the experiments. Currently we're running databases for magnetic field data from various ground-based and satellite related experiments, historical balloon data included. Comparisons of data between experiments are possible. This framework based on dependability considerations with several different

  18. Soft 3D acoustic metamaterial with negative index.

    PubMed

    Brunet, Thomas; Merlin, Aurore; Mascaro, Benoit; Zimny, Kevin; Leng, Jacques; Poncelet, Olivier; Aristégui, Christophe; Mondain-Monval, Olivier

    2015-04-01

    Many efforts have been devoted to the design and achievement of negative-refractive-index metamaterials since the 2000s. One of the challenges at present is to extend that field beyond electromagnetism by realizing three-dimensional (3D) media with negative acoustic indices. We report a new class of locally resonant ultrasonic metafluids consisting of a concentrated suspension of macroporous microbeads engineered using soft-matter techniques. The propagation of Gaussian pulses within these random distributions of 'ultra-slow' Mie resonators is investigated through in situ ultrasonic experiments. The real part of the acoustic index is shown to be negative (up to almost - 1) over broad frequency bandwidths, depending on the volume fraction of the microbeads as predicted by multiple-scattering calculations. These soft 3D acoustic metamaterials open the way for key applications such as sub-wavelength imaging and transformation acoustics, which require the production of acoustic devices with negative or zero-valued indices.

  19. Excavation Equipment Recognition Based on Novel Acoustic Statistical Features.

    PubMed

    Cao, Jiuwen; Wang, Wei; Wang, Jianzhong; Wang, Ruirong

    2016-09-30

    Excavation equipment recognition attracts increasing attentions in recent years due to its significance in underground pipeline network protection and civil construction management. In this paper, a novel classification algorithm based on acoustics processing is proposed for four representative excavation equipments. New acoustic statistical features, namely, the short frame energy ratio, concentration of spectrum amplitude ratio, truncated energy range, and interval of pulse are first developed to characterize acoustic signals. Then, probability density distributions of these acoustic features are analyzed and a novel classifier is presented. Experiments on real recorded acoustics of the four excavation devices are conducted to demonstrate the effectiveness of the proposed algorithm. Comparisons with two popular machine learning methods, support vector machine and extreme learning machine, combined with the popular linear prediction cepstral coefficients are provided to show the generalization capability of our method. A real surveillance system using our algorithm is developed and installed in a metro construction site for real-time recognition performance validation.

  20. CO2 leak detection through acoustic sensing and infrared imaging

    NASA Astrophysics Data System (ADS)

    Cui, Xiwang; Yan, Yong; Ma, Lin; Ma, Yifan; Han, Xiaojuan

    2014-04-01

    When CO2 leakage occurs from a high pressure enclosure, the CO2 jet formed can produce fierce turbulent flow generating acoustic emission with possible phase change, depending on the pressure of the enclosure, and a significant temperature drop in the region close to the releasing point. Acoustic Emission (AE) and infrared imaging technologiesare promising methods for on-line monitoring of such accidental leakage. In this paper, leakage experiments were carried out with a CO2 container under well controlled conditions in a laboratory. Acoustic signals and temperature distribution at the leakage area were acquired using an acoustic sensor and an infraredthermalimaging camera. The acoustic signal was analyzed in both time and frequency domains. The characteristics of the signal frequencies areidentified, and their suitability for leakage detectionis investigated. The location of the leakage can be identified by seeking the lowest temperature area or point in the infrared image.

  1. Laser-induced acoustic imaging of underground objects

    NASA Astrophysics Data System (ADS)

    Li, Wen; DiMarzio, Charles A.; McKnight, Stephen W.; Sauermann, Gerhard O.; Miller, Eric L.

    1999-02-01

    This paper introduces a new demining technique based on the photo-acoustic interaction, together with results from photo- acoustic experiments. We have buried different types of targets (metal, rubber and plastic) in different media (sand, soil and water) and imaged them by measuring reflection of acoustic waves generated by irradiation with a CO2 laser. Research has been focused on the signal acquisition and signal processing. A deconvolution method using Wiener filters is utilized in data processing. Using a uniform spatial distribution of laser pulses at the ground's surface, we obtained 3D images of buried objects. The images give us a clear representation of the shapes of the underground objects. The quality of the images depends on the mismatch of acoustic impedance of the buried objects, the bandwidth and center frequency of the acoustic sensors and the selection of filter functions.

  2. Shape-adaptable hyperlens for acoustic magnifying imaging

    NASA Astrophysics Data System (ADS)

    Zhang, Hongkuan; Zhou, Xiaoming; Hu, Gengkai

    2016-11-01

    Previous prototypes of acoustic hyperlens consist of rigid channels, which are unable to adapt in shape to the object under detection. We propose to overcome this limitation by employing soft plastic tubes that could guide acoustics with robustness against bending deformation. Based on the idea of soft-tube acoustics, acoustic magnifying hyperlens with planar input and output surfaces has been fabricated and validated experimentally. The shape-adaption capability of the soft-tube hyperlens is demonstrated by a controlled experiment, in which the magnifying super-resolution images remain stable when the lens input surface is curved. Our study suggests a feasible route toward constructing the flexible channel-structured acoustic metamaterials with the shape-adaption capability, opening then an additional degree of freedom for full control of sound.

  3. Estimating animal population density using passive acoustics.

    PubMed

    Marques, Tiago A; Thomas, Len; Martin, Stephen W; Mellinger, David K; Ward, Jessica A; Moretti, David J; Harris, Danielle; Tyack, Peter L

    2013-05-01

    Reliable estimation of the size or density of wild animal populations is very important for effective wildlife management, conservation and ecology. Currently, the most widely used methods for obtaining such estimates involve either sighting animals from transect lines or some form of capture-recapture on marked or uniquely identifiable individuals. However, many species are difficult to sight, and cannot be easily marked or recaptured. Some of these species produce readily identifiable sounds, providing an opportunity to use passive acoustic data to estimate animal density. In addition, even for species for which other visually based methods are feasible, passive acoustic methods offer the potential for greater detection ranges in some environments (e.g. underwater or in dense forest), and hence potentially better precision. Automated data collection means that surveys can take place at times and in places where it would be too expensive or dangerous to send human observers. Here, we present an overview of animal density estimation using passive acoustic data, a relatively new and fast-developing field. We review the types of data and methodological approaches currently available to researchers and we provide a framework for acoustics-based density estimation, illustrated with examples from real-world case studies. We mention moving sensor platforms (e.g. towed acoustics), but then focus on methods involving sensors at fixed locations, particularly hydrophones to survey marine mammals, as acoustic-based density estimation research to date has been concentrated in this area. Primary among these are methods based on distance sampling and spatially explicit capture-recapture. The methods are also applicable to other aquatic and terrestrial sound-producing taxa. We conclude that, despite being in its infancy, density estimation based on passive acoustic data likely will become an important method for surveying a number of diverse taxa, such as sea mammals, fish, birds

  4. Estimating animal population density using passive acoustics

    PubMed Central

    Marques, Tiago A; Thomas, Len; Martin, Stephen W; Mellinger, David K; Ward, Jessica A; Moretti, David J; Harris, Danielle; Tyack, Peter L

    2013-01-01

    Reliable estimation of the size or density of wild animal populations is very important for effective wildlife management, conservation and ecology. Currently, the most widely used methods for obtaining such estimates involve either sighting animals from transect lines or some form of capture-recapture on marked or uniquely identifiable individuals. However, many species are difficult to sight, and cannot be easily marked or recaptured. Some of these species produce readily identifiable sounds, providing an opportunity to use passive acoustic data to estimate animal density. In addition, even for species for which other visually based methods are feasible, passive acoustic methods offer the potential for greater detection ranges in some environments (e.g. underwater or in dense forest), and hence potentially better precision. Automated data collection means that surveys can take place at times and in places where it would be too expensive or dangerous to send human observers. Here, we present an overview of animal density estimation using passive acoustic data, a relatively new and fast-developing field. We review the types of data and methodological approaches currently available to researchers and we provide a framework for acoustics-based density estimation, illustrated with examples from real-world case studies. We mention moving sensor platforms (e.g. towed acoustics), but then focus on methods involving sensors at fixed locations, particularly hydrophones to survey marine mammals, as acoustic-based density estimation research to date has been concentrated in this area. Primary among these are methods based on distance sampling and spatially explicit capture-recapture. The methods are also applicable to other aquatic and terrestrial sound-producing taxa. We conclude that, despite being in its infancy, density estimation based on passive acoustic data likely will become an important method for surveying a number of diverse taxa, such as sea mammals, fish, birds

  5. 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.

  6. 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

  7. Improving Fidelity of Launch Vehicle Liftoff Acoustic Simulations

    NASA Technical Reports Server (NTRS)

    Liever, Peter; West, Jeff

    2016-01-01

    Launch vehicles experience high acoustic loads during ignition and liftoff affected by the interaction of rocket plume generated acoustic waves with launch pad structures. Application of highly parallelized Computational Fluid Dynamics (CFD) analysis tools optimized for application on the NAS computer systems such as the Loci/CHEM program now enable simulation of time-accurate, turbulent, multi-species plume formation and interaction with launch pad geometry and capture the generation of acoustic noise at the source regions in the plume shear layers and impingement regions. These CFD solvers are robust in capturing the acoustic fluctuations, but they are too dissipative to accurately resolve the propagation of the acoustic waves throughout the launch environment domain along the vehicle. A hybrid Computational Fluid Dynamics and Computational Aero-Acoustics (CFD/CAA) modeling framework has been developed to improve such liftoff acoustic environment predictions. The framework combines the existing highly-scalable NASA production CFD code, Loci/CHEM, with a high-order accurate discontinuous Galerkin (DG) solver, Loci/THRUST, developed in the same computational framework. Loci/THRUST employs a low dissipation, high-order, unstructured DG method to accurately propagate acoustic waves away from the source regions across large distances. The DG solver is currently capable of solving up to 4th order solutions for non-linear, conservative acoustic field propagation. Higher order boundary conditions are implemented to accurately model the reflection and refraction of acoustic waves on launch pad components. The DG solver accepts generalized unstructured meshes, enabling efficient application of common mesh generation tools for CHEM and THRUST simulations. The DG solution is coupled with the CFD solution at interface boundaries placed near the CFD acoustic source regions. Both simulations are executed simultaneously with coordinated boundary condition data exchange.

  8. NASA Rat Acoustic Tolerance Test 1994-1995: 8 kHz, 16 kHz, 32 kHz Experiments

    NASA Technical Reports Server (NTRS)

    Mele, Gary D.; Holley, Daniel C.; Naidu, Sujata

    1996-01-01

    Adult male Sprague-Dawley rats were exposed to chronic applied sound (74 to 79 dB, SPL) with octave band center frequencies of either 8, 16 or 32 kHz for up to 60 days. Control cages had ambient sound levels of about 62 dB (SPL). Groups of rats (test vs. control; N=9 per group) were euthanized after 0. 5. 14, 30, and 60 days. On each euthanasia day, objective evaluation of their physiology and behavior was performed using a Stress Assessment Battery (SAB) of measures. In addition, rat hearing was assessed using the brain stem auditory evoked potential (BAER) method after 60 days of exposure. No statistically significant differences in mean daily food use could be attributed to the presence of the applied test sound. Test rats used 5% more water than control rats. In the 8 kHz and 32 kHz tests this amount was statistically significant(P less than .05). This is a minor difference of questionable physiological significance. However, it may be an indication of a small reaction to the constant applied sound. Across all test frequencies, day 5 test rats had 6% larger spleens than control rats. No other body or organ weight differences were found to be statistically significant with respect to the application of sound. This spleen effect may be a transient adaptive process related to adaptation to the constant applied noise. No significant test effect on differential white blood cell counts could be demonstrated. One group demonstrated a low eosinophil count (16 kHz experiment, day 14 test group). However this was highly suspect. Across all test frequencies studied, day 5 test rats had 17% fewer total leukocytes than day 5 control rats. Sound exposed test rats exhibited 44% lower plasma corticosterone concentrations than did control rats. Note that the plasma corticosterone concentration was lower in the sound exposed test animals than the control animals in every instance (frequency exposure and number of days exposed).

  9. Arbitrary electron acoustic waves in degenerate dense plasmas

    NASA Astrophysics Data System (ADS)

    Rahman, Ata-ur; Mushtaq, A.; Qamar, A.; Neelam, S.

    2016-12-01

    A theoretical investigation is carried out of the nonlinear dynamics of electron-acoustic waves in a collisionless and unmagnetized plasma whose constituents are non-degenerate cold electrons, ultra-relativistic degenerate electrons, and stationary ions. A dispersion relation is derived for linear EAWs. An energy integral equation involving the Sagdeev potential is derived, and basic properties of the large amplitude solitary structures are investigated in such a degenerate dense plasma. It is shown that only negative large amplitude EA solitary waves can exist in such a plasma system. The present analysis may be important to understand the collective interactions in degenerate dense plasmas, occurring in dense astrophysical environments as well as in laser-solid density plasma interaction experiments.

  10. Dynamic performance of dielectric elastomers utilized as acoustic actuators

    NASA Astrophysics Data System (ADS)

    Hochradel, K.; Rupitsch, S. J.; Sutor, A.; Lerch, R.; Vu, D. K.; Steinmann, P.

    2012-06-01

    We report on the frequency dependent behavior of dielectric elastomer actuators (DEA). The introduced smart material actuators consist of 3M™'s elastomer VHB™4905 (9469) and a compliant, sputtered copper electrode on each side. The presented experiments on these compounds contain the active tuning of their resonance frequency and their application as acoustic actuators. We are able to decrease the membranes' eigenfrequency by 30% with an electrical offset potential. Alternatively, if an alternating signal is applied, sound pressure levels up to 130 dB in an enclosed volume of 28 ccm are achieved. In order to verify the results, a numerical simulation is introduced incorporating the two physical fields involved: electrical and mechanical.

  11. The Effects of Student Involvement and College Environment on Students' Learning and Living Experience at World-Class Research Universities in China: A Comparative Case Study of the University of Hong Kong (HKU) and Shanghai Jiao Tong University (SJTU)

    ERIC Educational Resources Information Center

    Chan, Roy Yew-Hung

    2011-01-01

    This comparative research examined the effects of student involvement and college environment on students' learning and living experience delivered by two aspiring world-class universities in Hong Kong and Shanghai. Few studies have shown how the levels of student involvement and college environment can benefit students at world-class institution.…

  12. What is involved in medicines management across care boundaries? A qualitative study of healthcare practitioners' experiences in the case of acute kidney injury

    PubMed Central

    Morris, Rebecca L; Blakeman, Tom; Ashcroft, Darren M

    2017-01-01

    Objectives To examine the role of individual and collective cognitive work in managing medicines for acute kidney injury (AKI), this being an example of a clinical scenario that crosses the boundaries of care organisations and specialties. Design Qualitative design, informed by a realist perspective and using semistructured interviews as the data source. The data were analysed using template analysis. Setting Primary, secondary and intermediate care in England. Participants 12 General practitioners, 10 community pharmacists, 7 hospital doctors and 7 hospital pharmacists, all with experience of involvement in preventing or treating AKI. Results We identified three main themes concerning participants' experiences of managing medicines in AKI. In the first theme, challenges arising from the clinical context, AKI is identified as a technically complex condition to identify and treat, often requiring judgements to be made about renal functioning against the context of the patient's general well-being. In the second theme, challenges arising from the organisational context, the crossing of professional and organisational boundaries is seen to introduce problems for the coordination of clinical activities, for example by disrupting information flows. In the third theme, meeting the challenges, participants identify ways in which they overcome the challenges they face in order to ensure effective medicines management, for example by adapting their work practices and tools. Conclusions These themes indicate the critical role of cognitive work on the part of healthcare practitioners, as individuals and as teams, in ensuring effective medicines management during AKI. Our findings suggest that the capabilities underlying this work, for example decision-making, communication and team coordination, should be the focus of training and work design interventions to improve medicines management for AKI or for other conditions. PMID:28100559

  13. Acoustical properties of drill strings

    SciTech Connect

    Drumheller, D.S.

    1988-08-01

    The recovery of petrochemical and geothermal resources requires extensive drilling of wells to increasingly greater depths. Real-time collection and telemetry of data about the drilling process while it occurs thousands of feet below the surface is an effective way of improving the efficiency of drilling operations. Unfortunately, due to hostile down-hole environments, telemetry of this data is an extremely difficult problem. Currently, commercial systems transmit data to the surface by producing pressure pulses within the portion of the drilling mud enclosed in the hollow steel drill string. Transmission rates are between two and four data bits per second. Any system capable of raising data rates without increasing the complexity of the drilling process will have significant economic impact. One alternative system is based upon acoustical carrier waves generated within the drill string itself. If developed, this method would accommodate data rates up to 100 bits per second. Unfortunately, the drill string is a periodic structure of pipe and threaded tool joints, the transmission characteristics are very complex and exhibit a banded and dispersive structure. Over the past forty years, attempts to field systems based upon this transmission method have resulted in little success. This paper examines this acoustical transmission problem in great detail. The basic principles of acoustic wave propagation in the periodic structure of the drill string are examined through theory, laboratory experiment, and field test. The results indicate the existence of frequency bands which are virtually free of attenuation and suitable for data transmission at high bit rates. 9 refs., 38 figs., 2 tabs.

  14. An overview of acoustic telemetry

    SciTech Connect

    Drumheller, D.S.

    1992-01-01

    Acoustic telemetry has been a dream of the drilling industry for the past 50 years. It offers the promise of data rates which are one-hundred times greater than existing technology. Such a system would open the door to true logging-while-drilling technology and bring enormous profits to its developers. The basic idea is to produce an encoded sound wave at the bottom of the well, let it propagate up the steel drillpipe, and extract the data from the signal at the surface. Unfortunately, substantial difficulties arise. The first difficult problem is to produce the sound wave. Since the most promising transmission wavelengths are about 20 feet, normal transducer efficiencies are quire low. Compounding this problem is the structural complexity of the bottomhole assembly and drillstring. For example, the acoustic impedance of the drillstring changes every 30 feet and produces an unusual scattering pattern in the acoustic transmission. This scattering pattern causes distortion of the signal and is often confused with signal attenuation. These problems are not intractable. Recent work has demonstrated that broad frequency bands exist which are capable of transmitting data at rates up to 100 bits per second. Our work has also identified the mechanism which is responsible for the observed anomalies in the patterns of signal attenuation. Furthermore in the past few years a body of experience has been developed in designing more efficient transducers for application to metal waveguides. The direction of future work is clear. New transducer designs which are more efficient and compatible with existing downhole power supplies need to be built and tested; existing field test data need to be analyzed for transmission bandwidth and attenuation; and the new and less expensive methods of collecting data on transmission path quality need to be incorporated into this effort. 11 refs.

  15. Acoustic emission monitoring system

    DOEpatents

    Romrell, Delwin M.

    1977-07-05

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

  16. High-frequency combustion instability control through acoustic modulation at the inlet boundary for liquid rocket engine applications

    NASA Astrophysics Data System (ADS)

    Bennewitz, John William

    This research investigation encompasses experimental tests demonstrating the control of a high-frequency combustion instability by acoustically modulating the propellant flow. A model rocket combustor burned gaseous oxygen and methane using a single-element, pentad-style injector. Flow conditions were established that spontaneously excited a 2430 Hz first longitudinal combustion oscillation at an amplitude up to p'/pc ≈ 6%. An acoustic speaker was placed at the base of the oxidizer supply to modulate the flow and alter the oscillatory behavior of the combustor. Two speaker modulation approaches were investigated: (1) Bands of white noise and (2) Pure sinusoidal tones. The first approach adjusted 500 Hz bands of white noise ranging from 0-500 Hz to 2000-2500 Hz, while the second implemented single-frequency signals with arbitrary phase swept from 500-2500 Hz. The results showed that above a modulation signal amplitude threshold, both approaches suppressed 95+% of the spontaneous combustion oscillation. By increasing the applied signal amplitude, a wider frequency range of instability suppression became present for these two acoustic modulation approaches. Complimentary to these experiments, a linear modal analysis was undertaken to investigate the effects of acoustic modulation at the inlet boundary on the longitudinal instability modes of a dump combustor. The modal analysis employed acoustically consistent matching conditions with a specific impedance boundary condition at the inlet to represent the acoustic modulation. From the modal analysis, a naturally unstable first longitudinal mode was predicted in the absence of acoustic modulation, consistent with the spontaneously excited 2430 Hz instability observed experimentally. Subsequently, a detailed investigation involving variation of the modulation signal from 0-2500 Hz and mean combustor temperature from 1248-1685 K demonstrated the unstable to stable transition of a 2300-2500 Hz first longitudinal mode. The

  17. Millimeter Waves: Acoustic and Electromagnetic

    PubMed Central

    Ziskin, Marvin C.

    2012-01-01

    This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects. PMID:22926874

  18. Millimeter waves: acoustic and electromagnetic.

    PubMed

    Ziskin, Marvin C

    2013-01-01

    This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects.

  19. The Acoustic Emission signal acquired by the microphones placed in the CABRI test device along the fourteen last R.I.A. experiments: an example of reproducible research in nuclear science

    SciTech Connect

    Laurent Pantera, Oumar Traore

    2015-07-01

    graphics representations were not straightforward to reproduce from the ancient studies since that, on one hand, people who were in charge of the original work left the laboratory and on the other hand because it is not easy when the time passes, even with our own work, to be able to remember the steps of data manipulations and the exact setup: - During the ancient experiments the use of analog data acquisition systems required to digitize tapes to be able to realize computer treatments. That had had for consequence to lose the initial dating. This one must be correctly edited to do temporal comparisons. - Analyses require functions for calculations whose parameters has to be well-known to reach the same results. We thus wished to manage our workflow in the idea that it can be easily reproducible on all the experiments. The object of the work presented in this article was to put in practice this strong bind between the data, treatments and generation of the document in order not to hesitate to do the iteration principle in action. We do not have to be afraid by the data driven analyses. According to the philosophy of the literate programming, the text of the technical document is woven with the computer code that produces all the printed output as tables, graphs for the study eliminating hence the unrealistic cut and paste. This difficulty is not specific to the nuclear domain. For many years, researchers have been worked out solutions to this mundane issue. And, presently, new technologies and high-level programming languages offer us actual answers. We will firstly present the tools applied in our laboratory to implement this workflow, then we will describe the global perception carried out to continue the study of the Acoustic Emission signals recorded by the two microphones during the fourteen last CABRI R.I.A. test.

  20. 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…