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Sample records for active sound control

  1. Active control of sound transmission using structural modal filters

    NASA Astrophysics Data System (ADS)

    Kaizuka, Tsutomu; Tanaka, Nobuo; Nakano, Kimihiko

    2016-10-01

    This paper addresses active sound transmission control based on structural sensors and actuators. The proposed methodology is to independently measure and control the targeted structural modes, which significantly contribute to sound transmission, with structural modal filters, i.e., modal sensors and modal actuators. The targeting is performed by using modal sound transmission coefficients before control as the criteria. The modal sound transmission coefficient enables the contribution from a structural mode to the sound transmission via the modal interaction with the other structural modes to be determined. The structural modal filters effectively facilitate decreasing the sound transmission and guarantee that the structural vibration and near-field sound, side effects of sound transmission control, will not increase. It is shown with numerical examples that sound transmission can be reduced significantly in a broad frequency band by controlling a small number of structural modes and neither the structural vibration nor near-field sound are increased.

  2. Active control of transmitted sound in buildings

    NASA Astrophysics Data System (ADS)

    Thompsett, Russell Harvey George

    The problem of noise from neighbours has increased dramatically over the last few years. Many of the noise complaints are due to the high level, low frequency noise from modern stereo equipment, and are often described in terms of the low frequency characteristics of the music; the repetitive, booming, bass beat. The objective of this research was to establish the feasibility of applying active noise control to alleviate this problem. The initial approach was to evaluate the possibility of exploiting the dominance of individual modes in the response of rooms at low frequency to effect global control. However, initial investigations using a modal model of the sound field revealed that this would be difficult due to the contribution of many acoustic modes excited off resonance. This conclusion was supported by measurements of acoustic room responses in typical buildings, illustrating a non-resonant characteristic. Consequently, attention was turned to the feasibility of using local active control systems to create zones of quiet by concentrating control at a specific location near the observers ears, for example in a seat headrest, or near the pillows of a bed. The lack of a reference signal in either approach requires the use of a feedback control strategy. With a typically non-resonant system, the predictability in the disturbance necessary for successful feedback control must be contained in the primary excitation, namely the music. Examples of different music styles were investigated and of those with the potential to be a nuisance surprisingly few were significantly more predictable than a random disturbance. As expected the most encouraging control performance simulations were found for modern dance music, with a strong repetitive beat. A real-time, local controller was demonstrated in the laboratory with such a disturbance signal and the properties of the quiet zone were measured. The subjective response when hearing the controller in operation was found to be

  3. Spherical loudspeaker array for local active control of sound.

    PubMed

    Rafaely, Boaz

    2009-05-01

    Active control of sound has been employed to reduce noise levels around listeners' head using destructive interference from noise-canceling sound sources. Recently, spherical loudspeaker arrays have been studied as multiple-channel sound sources, capable of generating sound fields with high complexity. In this paper, the potential use of a spherical loudspeaker array for local active control of sound is investigated. A theoretical analysis of the primary and secondary sound fields around a spherical sound source reveals that the natural quiet zones for the spherical source have a shell-shape. Using numerical optimization, quiet zones with other shapes are designed, showing potential for quiet zones with extents that are significantly larger than the well-known limit of a tenth of a wavelength for monopole sources. The paper presents several simulation examples showing quiet zones in various configurations.

  4. Active control of excessive sound emission on a mobile device.

    PubMed

    Jeon, Se-Woon; Youn, Dae Hee; Park, Young-cheol; Lee, Gun-Woo

    2015-04-01

    During a phone conversation, loud vocal emission from the far-end to the near-end space can disturb nearby people. In this paper, the possibility of actively controlling such unwanted sound emission using a control source placed on the mobile device is investigated. Two different approaches are tested: Global control, minimizing the potential energy measured along a volumetric space surface, and local control, minimizing the squared sound pressure at a discrete point on the phone. From the test results, both approaches can reduce the unwanted sound emission by more than 6 dB in the frequency range up to 2 kHz. PMID:25920885

  5. Active control of excessive sound emission on a mobile device.

    PubMed

    Jeon, Se-Woon; Youn, Dae Hee; Park, Young-cheol; Lee, Gun-Woo

    2015-04-01

    During a phone conversation, loud vocal emission from the far-end to the near-end space can disturb nearby people. In this paper, the possibility of actively controlling such unwanted sound emission using a control source placed on the mobile device is investigated. Two different approaches are tested: Global control, minimizing the potential energy measured along a volumetric space surface, and local control, minimizing the squared sound pressure at a discrete point on the phone. From the test results, both approaches can reduce the unwanted sound emission by more than 6 dB in the frequency range up to 2 kHz.

  6. Active Noise Control Experiments using Sound Energy Flu

    NASA Astrophysics Data System (ADS)

    Krause, Uli

    2015-03-01

    This paper reports on the latest results concerning the active noise control approach using net flow of acoustic energy. The test set-up consists of two loudspeakers simulating the engine noise and two smaller loudspeakers which belong to the active noise system. The system is completed by two acceleration sensors and one microphone per loudspeaker. The microphones are located in the near sound field of the loudspeakers. The control algorithm including the update equation of the feed-forward controller is introduced. Numerical simulations are performed with a comparison to a state of the art method minimising the radiated sound power. The proposed approach is experimentally validated.

  7. [Actuator placement for active sound and vibration control

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Two refereed journal publications and ten talks given at conferences, seminars, and colloquia resulted from research supported by NASA. They are itemized in this report. The two publications were entitled "Reactive Tabu and Search Sensor Selection in Active Structural Acoustic Control Problems" and "Quelling Cabin Noise in Turboprop Aircraft via Active Control." The conference presentations covered various aspects of actuator placement, including location problems, for active sound and vibration control of cylinders, of commuter jets, of propeller driven or turboprop aircraft, and for quelling aircraft cabin or interior noise.

  8. Quadratic Optimization in the Problems of Active Control of Sound

    NASA Technical Reports Server (NTRS)

    Loncaric, J.; Tsynkov, S. V.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    We analyze the problem of suppressing the unwanted component of a time-harmonic acoustic field (noise) on a predetermined region of interest. The suppression is rendered by active means, i.e., by introducing the additional acoustic sources called controls that generate the appropriate anti-sound. Previously, we have obtained general solutions for active controls in both continuous and discrete formulations of the problem. We have also obtained optimal solutions that minimize the overall absolute acoustic source strength of active control sources. These optimal solutions happen to be particular layers of monopoles on the perimeter of the protected region. Mathematically, minimization of acoustic source strength is equivalent to minimization in the sense of L(sub 1). By contrast. in the current paper we formulate and study optimization problems that involve quadratic functions of merit. Specifically, we minimize the L(sub 2) norm of the control sources, and we consider both the unconstrained and constrained minimization. The unconstrained L(sub 2) minimization is certainly the easiest problem to address numerically. On the other hand, the constrained approach allows one to analyze sophisticated geometries. In a special case, we call compare our finite-difference optimal solutions to the continuous optimal solutions obtained previously using a semi-analytic technique. We also show that the optima obtained in the sense of L(sub 2) differ drastically from those obtained in the sense of L(sub 1).

  9. Experimental active control of sound in the ATR 42

    NASA Astrophysics Data System (ADS)

    Paonessa, A.; Sollo, A.; Paxton, M.; Purver, M.; Ross, C. F.

    Passenger comfort is becoming day by day an important issue for the market of the regional turboprop aircraft and also for the future high speed propeller driven aircraft. In these aircraft the main contribution to the passenger annoyance is due to the propeller noise blade passing frequency (BPF) and its harmonics. In the recent past a detailed theoretical and experimental work has been done by Alenia Aeronautica in order to reduce the noise level in the ATR aircraft passenger cabin by means of conventional passive treatments: synchrophasing of propellers, dynamic vibration absorbers, structural reinforcements, damping materials. The application of these treatments has been introduced on production aircraft with a remarkable improvement of noise comfort but with a significant weight increase. For these reasons, a major technology step is required for reaching passenger comfort comparable to that of jet aircraft with the minimum weight increase. The most suitable approach to this problem has been envisaged in the active noise control which consists in generating an anti-sound field in the passenger cabin to reduce the noise at propeller BPF and its harmonics. The attenuation is reached by means of a control system which acquires information about the cabin noise distribution and the propeller speed during flight and simultaneously generates the signals to drive the speakers.

  10. Active control of sound fields in elastic cylinders by multi-control forces

    NASA Technical Reports Server (NTRS)

    Jones, J. D.; Fuller, C. R.

    1987-01-01

    An unstiffened cylindrical model was used to study the control of sound transmission into aircraft cabins by the use of multi-control forces applied directly to the cylinder wall. External acoustic monopoles were located on each side of the cylinder to approximate the propeller noise source. This allowed the study of a dual control system utilizing multi-control forces in conjunction with synchrophasing of the twin acoustic monopole sources. For acoustic resonant conditions within the cavity, a spatially averaged noise reduction of approximately 30 dB was achieved using the active control system for both in-phase and out-of-phase monopoles; however, effective reduction of the sound field was dependent upon judiciously positioning the control forces for optimal control of the sound field.

  11. Active control of sound transmission through partitions composed of discretely controlled modules

    NASA Astrophysics Data System (ADS)

    Leishman, Timothy W.

    This thesis provides a detailed theoretical and experimental investigation of active segmented partitions (ASPs) for the control of sound transmission. ASPs are physically segmented arrays of interconnected acoustically and structurally small modules that are discretely controlled using electronic controllers. Theoretical analyses of the thesis first address physical principles fundamental to ASP modeling and experimental measurement techniques. Next, they explore specific module configurations, primarily using equivalent circuits. Measured normal-incidence transmission losses and related properties of experimental ASPs are determined using plane wave tubes and the two-microphone transfer function technique. A scanning laser vibrometer is also used to evaluate distributed transmitting surface vibrations. ASPs have the inherent potential to provide excellent active sound transmission control (ASTC) through lightweight structures, using very practical control strategies. The thesis analyzes several unique ASP configurations and evaluates their abilities to produce high transmission losses via global minimization of normal transmitting surface vibrations. A novel dual diaphragm configuration is shown to employ this strategy particularly well. It uses an important combination of acoustical actuation and mechano-acoustical segmentation to produce exceptionally high transmission loss (e.g., 50 to 80 dB) over a broad frequency range-including lower audible frequencies. Such performance is shown to be comparable to that produced by much more massive partitions composed of thick layers of steel or concrete and sand. The configuration uses only simple localized error sensors and actuators, permitting effective use of independent single-channel controllers in a decentralized format. This work counteracts the commonly accepted notion that active vibration control of partitions is an ineffective means of controlling sound transmission. With appropriate construction, actuation

  12. Active control of sound fields in elastic cylinders by vibrational inputs

    NASA Technical Reports Server (NTRS)

    Jones, J. D.; Fuller, C. R.

    1987-01-01

    An experiment is performed to study the mechanisms of active control of sound fields in elastic cylinders via vibrational outputs. In the present method of control, a vibrational force input was used as the secondary control input to reduce the radiated acoustic field. For the frequencies considered, the active vibration technique provided good global reduction of interior sound even though only one actuator was used.

  13. A multi-harmonic amplitude and relative-phase controller for active sound quality control

    NASA Astrophysics Data System (ADS)

    Mosquera-Sánchez, Jaime A.; de Oliveira, Leopoldo P. R.

    2014-04-01

    Current active sound quality control systems aim at dealing with the amplitude level of the primary disturbance, e.g. sound pressure, forces, velocities and/or accelerations, which implicitly leads to Loudness control, regardless of the spectral structure of the disturbance. As far as multi-harmonic disturbances are concerned, auditory Roughness, arguably the most related psychoacoustic metric with rumbling perception in passenger cars, can be tackled not merely by dealing with magnitudes but also with the relative-phase of the narrowband components. This paper presents an adaptive control scheme conceived for dealing with multi-harmonic disturbances, which features the independent amplitude and/or relative-phase control of the input periodic components and an improved robustness to impulsive events. The adaptive control scheme is based on a frequency-domain delayless implementation of the complex-domain, least mean squares algorithm, whereof its convergence process is improved by using a forgetting factor. The control capabilities are evaluated numerically for single- and multiple-harmonic disturbances, including realistic internal combustion engine sound contaminated with noise and by impulsive events. By using long transfer paths obtained from a real vehicle mock-up, sound pressure level reductions of 39 dBSPL and the ability to displacing the relative-phase of a number of narrowband components between [-π,π] are accomplished by the proposed control scheme. The assessment of the results by using Zwicker-Loudness and auditory Roughness models shows that the proposed adaptive algorithm is able to accomplish and stably preserve various sound quality targets, after completion of the robust convergence procedure, regardless of impulsive events that can occur during the system operation.

  14. Performance of active feedforward control systems in non-ideal, synthesized diffuse sound fields.

    PubMed

    Misol, Malte; Bloch, Christian; Monner, Hans Peter; Sinapius, Michael

    2014-04-01

    The acoustic performance of passive or active panel structures is usually tested in sound transmission loss facilities. A reverberant sending room, equipped with one or a number of independent sound sources, is used to generate a diffuse sound field excitation which acts as a disturbance source on the structure under investigation. The spatial correlation and coherence of such a synthesized non-ideal diffuse-sound-field excitation, however, might deviate significantly from the ideal case. This has consequences for the operation of an active feedforward control system which heavily relies on the acquisition of coherent disturbance source information. This work, therefore, evaluates the spatial correlation and coherence of ideal and non-ideal diffuse sound fields and considers the implications on the performance of a feedforward control system. The system under consideration is an aircraft-typical double panel system, equipped with an active sidewall panel (lining), which is realized in a transmission loss facility. Experimental results for different numbers of sound sources in the reverberation room are compared to simulation results of a comparable generic double panel system excited by an ideal diffuse sound field. It is shown that the number of statistically independent noise sources acting on the primary structure of the double panel system depends not only on the type of diffuse sound field but also on the sample lengths of the processed signals. The experimental results show that the number of reference sensors required for a defined control performance exhibits an inverse relationship to control filter length. PMID:25234987

  15. Performance of active feedforward control systems in non-ideal, synthesized diffuse sound fields.

    PubMed

    Misol, Malte; Bloch, Christian; Monner, Hans Peter; Sinapius, Michael

    2014-04-01

    The acoustic performance of passive or active panel structures is usually tested in sound transmission loss facilities. A reverberant sending room, equipped with one or a number of independent sound sources, is used to generate a diffuse sound field excitation which acts as a disturbance source on the structure under investigation. The spatial correlation and coherence of such a synthesized non-ideal diffuse-sound-field excitation, however, might deviate significantly from the ideal case. This has consequences for the operation of an active feedforward control system which heavily relies on the acquisition of coherent disturbance source information. This work, therefore, evaluates the spatial correlation and coherence of ideal and non-ideal diffuse sound fields and considers the implications on the performance of a feedforward control system. The system under consideration is an aircraft-typical double panel system, equipped with an active sidewall panel (lining), which is realized in a transmission loss facility. Experimental results for different numbers of sound sources in the reverberation room are compared to simulation results of a comparable generic double panel system excited by an ideal diffuse sound field. It is shown that the number of statistically independent noise sources acting on the primary structure of the double panel system depends not only on the type of diffuse sound field but also on the sample lengths of the processed signals. The experimental results show that the number of reference sensors required for a defined control performance exhibits an inverse relationship to control filter length.

  16. Feedback control of sound

    NASA Astrophysics Data System (ADS)

    Rafaely, Boaz

    This thesis is concerned with the development an application of feedback control techniques for active sound control. Both fixed and adaptive controllers are considered. The controller design problem for active sound control is formulated as a constrained optimisation problem with an H2 performance objective, of minimising the variance of the control error, and H2 and H∞ design constraints involving control power output, disturbance enhancement, and robust stability. An Internal Model Controller with an FIR control filter is assumed. Conventional H2 design methods for feedback controllers are studied first. Although such controllers can satisfy the design constraints by employing effort terms in the quadratic cost function, they do not achieve the best possible performance, and when adapted using LMS-based algorithms, they suffer from instabilities if the plant response varies significantly. Improved H2/H∞ design methods for fixed and adaptive controllers are then developed, which achieve the best H2 performance under the design constraints, offer an improved stability when made adaptive, and in general outperform the conventional H2 controllers. The H2/H∞ design problems employ convex programming to ensure a unique solution. The Sequential Quadratic Programming methods is used for the off-line design of fixed controllers, and penalty and barrier function methods, together with frequency domain LMS-based algorithms are employed in the H2/H∞ adaptive controllers. The controllers studied and developed here were applied to three active sound control systems: a noise-reducing headset, an active headrest, and a sound radiating panel. The emphasis was put on developing control strategies that improve system performance. First, a high performance controller for the noise-reducing headset was implemented in real-time, which combines analogue and adaptive digital controllers, and can thus reject disturbances which has both broad-band and periodic components. Then

  17. Active/Passive Control of Sound Radiation from Panels using Constrained Layer Damping

    NASA Technical Reports Server (NTRS)

    Gibbs, Gary P.; Cabell, Randolph H.

    2003-01-01

    A hybrid passive/active noise control system utilizing constrained layer damping and model predictive feedback control is presented. This system is used to control the sound radiation of panels due to broadband disturbances. To facilitate the hybrid system design, a methodology for placement of constrained layer damping which targets selected modes based on their relative radiated sound power is developed. The placement methodology is utilized to determine two constrained layer damping configurations for experimental evaluation of a hybrid system. The first configuration targets the (4,1) panel mode which is not controllable by the piezoelectric control actuator, and the (2,3) and (5,2) panel modes. The second configuration targets the (1,1) and (3,1) modes. The experimental results demonstrate the improved reduction of radiated sound power using the hybrid passive/active control system as compared to the active control system alone.

  18. Active control of sound radiation from a vibrating rectangular panel by sound sources and vibration inputs - An experimental comparison

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.; Hansen, C. H.; Snyder, S. D.

    1991-01-01

    Active control of sound radiation from a rectangular panel by two different methods has been experimentally studied and compared. In the first method a single control force applied directly to the structure is used with a single error microphone located in the radiated acoustic field. Global attenuation of radiated sound was observed to occur by two main mechanisms. For 'on-resonance' excitation, the control force had the effect of increasing the total panel input impedance presented to the nosie source, thus reducing all radiated sound. For 'off-resonance' excitation, the control force tends not significantly to modify the panel total response amplitude but rather to restructure the relative phases of the modes leading to a more complex vibration pattern and a decrease in radiation efficiency. For acoustic control, the second method, the number of acoustic sources required for global reduction was seen to increase with panel modal order. The mechanism in this case was that the acoustic sources tended to create an inverse pressure distribution at the panel surface and thus 'unload' the panel by reducing the panel radiation impedance. In general, control by structural inputs appears more effective than control by acoustic sources for structurally radiated noise.

  19. Actuator placement for active sound and vibration control of cylinders

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1995-01-01

    Active structural acoustic control is a method in which the control inputs (used to reduce interior noise) are applied directly to a vibrating structural acoustic system. The control concept modeled in this work is the application of in-plane force inputs to piezoceramic patches bonded to the wall of a vibrating cylinder. The cylinder is excited by an exterior noise source -- an acoustic monopole -- located near the outside of the cylinder wall. The goal is to determine the force inputs and sites for the piezoelectric actuators so that (1) the interior noise is effectively damped; (2) the level of vibration of the cylinder shell is not increased; and (3) the power requirements needed to drive the actuators are not excessive. We studied external monopole excitations at two frequencies. A cylinder resonance of 100 Hz, where the interior acoustic field is driven in multiple, off-resonance cylinder cavity modes, and a cylinder resonance of 200 Hz are characterized by both near and off-resonance cylinder vibration modes which couple effectively with a single, dominant, low-order acoustic cavity mode at resonance. Previous work has focused almost exclusively on meeting objective (1) and solving a complex least-squares problem to arrive at an optimal force vector for a given set of actuator sites. In addition, it has been noted that when the cavity mode couples with cylinder vibration modes (our 200 Hz case) control spillover may occur in higher order cylinder shell vibrational modes. How to determine the best set of actuator sites to meet objectives (1)-(3) is the main contribution of our research effort. The selection of the best set of actuator sites from a set of potential sites is done via two metaheuristics -- simulated annealing and tabu search. Each of these metaheuristics partitions the set of potential actuator sites into two disjoint sets: those that are selected to control the noise (on) and those that are not (off). Next, each metaheuristic attempts to

  20. Active control of structurally-coupled sound fields in elastic cylinders by vibrational force inputs

    NASA Technical Reports Server (NTRS)

    Jones, J. D.; Fuller, C. R.

    1990-01-01

    Active control of structurally-coupled sound fields in elastic cylinders is analytically and experimentally studied. The primary (noise) field in the cylinder model is generated by the coupled dynamic response of the shell under loading by a single exterior acoustic source. Control of the interior sound field is achieved by applying vibrational force inputs directly to the shell wall. Action of the point controllers serve to increase the input impedance of select structural modes of the shell which are well-coupled to the interior acoustic cavity, thus substantially reducing sound transmission into the cavity. Spatially-averaged noise reductions in excess of 30 dB are demonstrated for acoustic resonant conditions within the cavity. Twin controller configurations are presented which demonstrate the ability to independently control orthogonal modes of the interior acoustic space. Benefits and drawbacks of this new methodology for noise control are discussed and clearly demonstrated.

  1. Sound quality of low-frequency and car engine noises after active noise control

    NASA Astrophysics Data System (ADS)

    Gonzalez, A.; Ferrer, M.; de Diego, M.; Piñero, G.; Garcia-Bonito, J. J.

    2003-08-01

    The ability of active noise control (ANC) systems to achieve a more pleasant sound has been evaluated by means of sound quality analysis of a real multi-channel active noise controller. Recordings of real car engine noises had been carried out using a Head acoustics TM binaural head simulator seated in a typical car seat, and these signals together with synthesized noise have been actively controlled in an enclosed room. The sound quality study has focused on the estimation of noise quality changes through the evaluation of the sense of comfort. Two methods have been developed: firstly, a predictive method based on psychoacoustic parameters (loudness, roughness, tonality and sharpness); and secondly, a subjective method using a jury test. Both results have been related to the spectral characteristics of the sounds before and after active control. It can be concluded from both analyses that ANC positively affects acoustic comfort. The engine noise mathematical comfort predictor is based on loudness and roughness (two psychoacoustic parameters directly influenced by ANC), and has satisfactorily predicted the improvements in the pleasantness of the sounds. As far as the subjective evaluation method is concerned, the jury test has showed that acoustic comfort is, in most cases, directly related to the sense of quietness. However, ANC has also been assessed negatively by the jury in the cases that it was unable to reduce the loudness, perhaps because of the low amplitudes of the original sounds. Finally, from what has been shown, it can be said that the subjective improvements strongly depends on the attenuation level achieved by the ANC system operation, as well as the spectral characteristics of the sounds before and after control.

  2. Anticipated Effectiveness of Active Noise Control in Propeller Aircraft Interiors as Determined by Sound Quality Tests

    NASA Technical Reports Server (NTRS)

    Powell, Clemans A.; Sullivan, Brenda M.

    2004-01-01

    Two experiments were conducted, using sound quality engineering practices, to determine the subjective effectiveness of hypothetical active noise control systems in a range of propeller aircraft. The two tests differed by the type of judgments made by the subjects: pair comparisons in the first test and numerical category scaling in the second. Although the results of the two tests were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference.

  3. Investigation of spherical loudspeaker arrays for local active control of sound.

    PubMed

    Peleg, Tomer; Rafaely, Boaz

    2011-10-01

    Active control of sound can be employed globally to reduce noise levels in an entire enclosure, or locally around a listener's head. Recently, spherical loudspeaker arrays have been studied as multiple-channel sources for local active control of sound, presenting the fundamental theory and several active control configurations. In this paper, important aspects of using a spherical loudspeaker array for local active control of sound are further investigated. First, the feasibility of creating sphere-shaped quiet zones away from the source is studied both theoretically and numerically, showing that these quiet zones are associated with sound amplification and poor system robustness. To mitigate the latter, the design of shell-shaped quiet zones around the source is investigated. A combination of two spherical sources is then studied with the aim of enlarging the quiet zone. The two sources are employed to generate quiet zones that surround a rigid sphere, investigating the application of active control around a listener's head. A significant improvement in performance is demonstrated in this case over a conventional headrest-type system that uses two monopole secondary sources. Finally, several simulations are presented to support the theoretical work and to demonstrate the performance and limitations of the system.

  4. Active Control of Turbulent Boundary Layer Induced Sound Radiation from Multiple Aircraft Panels

    NASA Technical Reports Server (NTRS)

    Gibbs, Gary P.; Cabell, Randolph H.

    2002-01-01

    The objective of this work is to experimentally investigate active structural acoustic control of turbulent boundary layer (TBL) induced sound radiation from multiple panels on an aircraft sidewall. One possible approach for controlling sound radiation from multiple panels is a multi-input/multi-output scheme which considers dynamic coupling between the panels. Unfortunately, this is difficult for more than a few panels, and is impractical for a typical aircraft which contains several hundred such panels. An alternative is to implement a large number of independent control systems. Results from the current work demonstrate the feasibility of reducing broadband radiation from multiple panels utilizing a single-input/single-output (SISO) controller per bay, and is the first known demonstration of active control of TBL induced sound radiation on more than two bays simultaneously. The paper compares sound reduction for fully coupled control of six panels versus independent control on each panel. An online adaptive control scheme for independent control is also demonstrated. This scheme will adjust for slow time varying dynamic systems such as fuselage response changes due to aircraft pressurization, etc.

  5. Active control of sound transmission/radiation from elastic plates by vibration inputs. II - Experiments

    NASA Technical Reports Server (NTRS)

    Metcalf, V. L.; Fuller, C. R.; Silcox, R. J.; Brown, D. E.

    1992-01-01

    Actively controlled harmonic force inputs were applied experimentally to reduce the sound transmitted through an elastic circular plate. The control implementation used a time domain least mean square adaptive algorithm with two error sensors. The control forces were applied directly to the plate by point force vibration inputs, while the error information and performance were measured in the radiated acoustic field by microphones. Test cases were also performed in which the error sensors were accelerometers mounted on the plate. When accelerometers were used as error sensors, the controller performance was degraded; leading to the conclusion that minimizing plate motion does not necessarily lead to an associated decrease in radiated sound levels. In contrast, the results show excellent attenuation of the transmitted sound field when microphone error sensors were used. This result was consistent over a range of frequencies. In addition, the experimental results are compared to previously derived analytical results and the effect of using a point or global minimization scheme is discussed.

  6. Reduction of interior sound fields in flexible cylinders by active vibration control

    NASA Technical Reports Server (NTRS)

    Jones, J. D.; Fuller, C. R.

    1988-01-01

    The mechanisms of interior sound reduction through active control of a thin flexible shell's vibrational response are presently evaluated in view of an analytical model. The noise source is a single exterior acoustic monopole. The active control model is evaluated for harmonic excitation; the results obtained indicate spatially-averaged noise reductions in excess of 20 dB over the source plane, for acoustic resonant conditions inside the cavity.

  7. Active control of aircraft engine inlet noise using compact sound sources and distributed error sensors

    NASA Technical Reports Server (NTRS)

    Burdisso, Ricardo (Inventor); Fuller, Chris R. (Inventor); O'Brien, Walter F. (Inventor); Thomas, Russell H. (Inventor); Dungan, Mary E. (Inventor)

    1996-01-01

    An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x LMS algorithm. Single multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. A multi channel control system is used to control any spinning mode. The multi channel control system to control both fan tones and a high pressure compressor BPF tone simultaneously. In order to make active control of turbofan inlet noise a viable technology, a compact sound source is employed to generate the control field. This control field sound source consists of an array of identical thin, cylindrically curved panels with an inner radius of curvature corresponding to that of the engine inlet. These panels are flush mounted inside the inlet duct and sealed on all edges to prevent leakage around the panel and to minimize the aerodynamic losses created by the addition of the panels. Each panel is driven by one or more piezoelectric force transducers mounted on the surface of the panel. The response of the panel to excitation is maximized when it is driven at its resonance; therefore, the panel is designed such that its fundamental frequency is near the tone to be canceled, typically 2000-4000 Hz.

  8. Active control of aircraft engine inlet noise using compact sound sources and distributed error sensors

    NASA Technical Reports Server (NTRS)

    Burdisso, Ricardo (Inventor); Fuller, Chris R. (Inventor); O'Brien, Walter F. (Inventor); Thomas, Russell H. (Inventor); Dungan, Mary E. (Inventor)

    1994-01-01

    An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x LMS algorithm. Single multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. A multi channel control system is used to control any spinning mode. The multi channel control system to control both fan tones and a high pressure compressor BPF tone simultaneously. In order to make active control of turbofan inlet noise a viable technology, a compact sound source is employed to generate the control field. This control field sound source consists of an array of identical thin, cylindrically curved panels with an inner radius of curvature corresponding to that of the engine inlet. These panels are flush mounted inside the inlet duct and sealed on all edges to prevent leakage around the panel and to minimize the aerodynamic losses created by the addition of the panels. Each panel is driven by one or more piezoelectric force transducers mounted on the surface of the panel. The response of the panel to excitation is maximized when it is driven at its resonance; therefore, the panel is designed such that its fundamental frequency is near the tone to be canceled, typically 2000-4000 Hz.

  9. An experimental investigation of the active control of sound transmission into a cylindrical enclosure

    NASA Technical Reports Server (NTRS)

    Snyder, S. D.; Hansen, C. H.; Fuller, C. R.

    1989-01-01

    Preliminary results are reported from experiments involving the use of vibration sources in the active control of sound transmission into a cylindrical chamber (as in aircraft cabin-noise suppression). Electrodynamic shakers are used to provide vibrational excitation in a 3-m-high 900-mm-diameter cylindrical stainless-steel chamber with damped ends, subjected to single-frequency (384-Hz) sound from a horn driver located 150 mm from the cylinder midway along its length. When vibration is applied only diametrically opposite the source, rotation of the sound field occurs, but global attenuation is not achieved; with additional vibration applied at an angle of 225 deg to the source, moderate reduction of the global field is obtained. The need to identify and control all offending coupled structural/acoustic modes is indicated.

  10. Active control of sound transmission/radiation from elastic plates by vibration inputs. I - Analysis

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.

    1990-01-01

    Active control of sound radiation from vibrating plates by oscillating forces applied directly to the structure is analytically studied. The model consists of a plane acoustic wave incident on a clamped elastic circular thin plate. Control is achieved by point forces, and quadratic optimization is used to calculate the optimal control gains necessary to minimize a cost function proportional to the radiated acoustic power (the transmitted field). The results show that global attenuation of broadband radiated sound levels for low to mid-range frequencies can be achieved with one or two control forces, irrespective of whether the system is on or off resonance. The efficiency of the control strategy is demonstrated to be related to the nature of the coupling between the plate modes of response and the radiated field.

  11. An analytical investigation of the active control of the transmission of sound through plates

    NASA Astrophysics Data System (ADS)

    Thomas, D. R.; Nelson, P. A.; Pinnington, R. J.; Elliott, S. J.

    1995-03-01

    An analytical model of a vibrating plate is used to explore the mechanisms of control involved in the reduction of harmonic sound transmission through the active control of plate vibration. A general model of the plate vibrations (previously used by Berry et al.) is presented, with the boundary conditions of the plate being modelled as variable rotational and translational elastic restraints at the edges of the plate. A variational formulation of the problem is presented and the equation of motion of the plate is derived by using a Rayleigh-Ritz method. Both an elastic plate with clamped edges and a rigid panel with free edges are considered. For the rigid panel it is found that large attenuations in transmitted sound can be obtained if either three control actuators are used (one for each rigid body mode) or the motion of the panel is restricted to piston type translation along an axis perpendicular to the panel. For the elastic plate two mechanisms of control are observed: "modal control" where the amplitudes of those modes which dominate sound radiation are reduced, and "modal rearrangement" where the relative amplitudes and phases of plate modes are adjusted to produce a vibration distribution of low radiation efficiency. The latter mechanism is shown to be both subtle (often involving little change in mode amplitudes and little change in the overall vibration amplitude of the plate) and very effective (accounting for a large proportion of the attenuations in radiated sound at most frequencies). For the frequency range of interest (0.92 less than kaless than 2.75) large attenuations in the transmitted sound could always be achieved if the number and positioning of the secondary forces is correctly chosen. The simulations also demonstrate the phenomenon of "spill-over", where inefficiently radiating plate modes are strongly excited with the introduction of control often resulting in an overall increase in the plate vibration.

  12. Active control of sound radiation from panels using embedded shape memory alloy fibers

    NASA Astrophysics Data System (ADS)

    Rogers, C. A.; Fuller, C. R.; Liang, C.

    1990-01-01

    The fundamental relations and techniques demonstrating active structural-acoustic control using shape memory alloy (SMA) reinforced composites are discussed. A symmetric SMA reinforced laminate is described by the governing equation, then the Rayleigh-Ritz method is used to obtain an approximate solution to the governing equation, and the assumed solution is employed for the necessary energy expression. Transmission of sound through the composite plates is analyzed, the calculated natural frequencies for the first ten natural frequencies of the inactivated and fully activated plate are presented, and the transmission loss for the SMA reinforced composite plates is calculated for both the activated and inactivated cases. It is shown that acoustically excited SMA reinforced composite plates have the ability to adaptively change radiation efficiency, transmission loss, and directivity patterns of transmitted sound.

  13. Active control of turbulent boundary layer sound transmission into a vehicle interior

    NASA Astrophysics Data System (ADS)

    Caiazzo, A.; Alujević, N.; Pluymers, B.; Desmet, W.

    2016-09-01

    In high speed automotive, aerospace, and railway transportation, the turbulent boundary layer (TBL) is one of the most important sources of interior noise. The stochastic pressure distribution associated with the turbulence is able to excite significantly structural vibration of vehicle exterior panels. They radiate sound into the vehicle through the interior panels. Therefore, the air flow noise becomes very influential when it comes to the noise vibration and harshness assessment of a vehicle, in particular at low frequencies. Normally, passive solutions, such as sound absorbing materials, are used for reducing the TBL-induced noise transmission into a vehicle interior, which generally improve the structure sound isolation performance. These can achieve excellent isolation performance at higher frequencies, but are unable to deal with the low-frequency interior noise components. In this paper, active control of TBL noise transmission through an acoustically coupled double panel system into a rectangular cavity is examined theoretically. The Corcos model of the TBL pressure distribution is used to model the disturbance. The disturbance is rejected by an active vibration isolation unit reacting between the exterior and the interior panels. Significant reductions of the low-frequency vibrations of the interior panel and the sound pressure in the cavity are observed.

  14. Active control and sound synthesis--two different ways to investigate the influence of the modal parameters of a guitar on its sound.

    PubMed

    Benacchio, Simon; Mamou-Mani, Adrien; Chomette, Baptiste; Finel, Victor

    2016-03-01

    The vibrational behavior of musical instruments is usually studied using physical modeling and simulations. Recently, active control has proven its efficiency to experimentally modify the dynamical behavior of musical instruments. This approach could also be used as an experimental tool to systematically study fine physical phenomena. This paper proposes to use modal active control as an alternative to sound simulation to study the complex case of the coupling between classical guitar strings and soundboard. A comparison between modal active control and sound simulation investigates the advantages, the drawbacks, and the limits of these two approaches.

  15. Active control and sound synthesis--two different ways to investigate the influence of the modal parameters of a guitar on its sound.

    PubMed

    Benacchio, Simon; Mamou-Mani, Adrien; Chomette, Baptiste; Finel, Victor

    2016-03-01

    The vibrational behavior of musical instruments is usually studied using physical modeling and simulations. Recently, active control has proven its efficiency to experimentally modify the dynamical behavior of musical instruments. This approach could also be used as an experimental tool to systematically study fine physical phenomena. This paper proposes to use modal active control as an alternative to sound simulation to study the complex case of the coupling between classical guitar strings and soundboard. A comparison between modal active control and sound simulation investigates the advantages, the drawbacks, and the limits of these two approaches. PMID:27036278

  16. Potential-based methodology for active sound control in three dimensional settings.

    PubMed

    Lim, H; Utyuzhnikov, S V; Lam, Y W; Kelly, L

    2014-09-01

    This paper extends a potential-based approach to active noise shielding with preservation of wanted sound in three-dimensional settings. The approach, which was described in a previous publication [Lim et al., J. Acoust. Soc. Am. 129(2), 717-725 (2011)], provides several significant advantages over conventional noise control methods. Most significantly, the methodology does not require any information including the characterization of sources, impedance boundary conditions and surrounding medium, and that the methodology automatically differentiates between the wanted and unwanted sound components. The previous publication proved the concept in one-dimensional conditions. In this paper, the approach for more realistic conditions is studied by numerical simulation and experimental validation in three-dimensional cases. The results provide a guideline to the implementation of the active shielding method with practical three-dimensional conditions. Through numerical simulation it is demonstrated that while leaving the wanted sound unchanged, the developed approach offers selective volumetric noise cancellation within a targeted domain. In addition, the method is implemented in a three-dimensional experiment with a white noise source in a semi-anechoic chamber. The experimental study identifies practical difficulties and limitations in the use of the approach for real applications. PMID:25190385

  17. Semi-active control of piezoelectric coating's underwater sound absorption by combining design of the shunt impedances

    NASA Astrophysics Data System (ADS)

    Sun, Yang; Li, Zhaohui; Huang, Aigen; Li, Qihu

    2015-10-01

    Piezoelectric shunt damping technology has been applied in the field of underwater sound absorption in recent years. In order to achieve broadband echo reduction, semi-active control of sound absorption of multi-layered piezoelectric coating by shunt damping is significant. In this paper, a practical method is proposed to control the underwater sound absorption coefficients of piezoelectric coating layers by combining design of the shunt impedance that allows certain sound absorption coefficients at setting frequencies. A one-dimensional electro-acoustic model of the piezoelectric coating and the backing is established based on the Mason equivalent circuit theory. First, the shunt impedance of the coating is derived under the constraint of sound absorption coefficient at one frequency. Then, taking the 1-3 piezoelectric composite coating as an example, the sound absorption properties of the coating shunted to the designed shunt impedance are investigated. Next, on the basis of that, an iterative method for two constrained frequencies and an optimizing algorithm for multiple constrained frequencies are provided for combining design of the shunt impedances. At last, an experimental sample with four piezoelectric material layers is manufactured, of which the sound absorption coefficients are measured in an impedance tube. The experimental results show good agreement with the finite element simulation results. It is proved that a serial R-L circuit can control the peak frequency, maximum and bandwidth of the sound absorption coefficient and the combining R-L circuits shunted to multiple layers can control the sound absorption coefficients at multiple frequencies.

  18. 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.

  19. Lightweight low-frequency woofer for active sound control in payload fairings

    NASA Astrophysics Data System (ADS)

    Corsaro, Robert D.

    2001-06-01

    A low-mass sound generator with particularly good performance at low audio frequencies (i.e. 30 to 300 Hz) has been developed. The actuation component is a Thunder actuator (Face Int. Corp.). This actuator is coupled to a resonant compliant diaphragm to increase output in the low frequency band. The modal response of various 28 cm diameter prototypes was monitored using laser Doppler vibrometry and nearfield acoustic holography. The first mode appears near 40 Hz, with a maximum displacement of 3.4 microns per volt. Sound pressure levels measured in the farfield using 200 volts peak drive found nominal levels of 74+/- 6 dB(at 25 cm) over the band from 38 to 330 Hz. Near 45 and 100 Hz the SPL reaches 80 dB. (Above 330 Hz the output is higher, but remains well behaved to at least 2 kHz.) Higher outputs can be obtained by using a higher drive voltage and multiple devices. Because of its low mass, this device is particularly interesting for aerospace applications. This work was developed in the NRL/ONR Smart Blanket program, which is exploring the use of active controlled surface covers for reducing sound levels in payload fairing regions.

  20. Physical mechanisms of active control of sound transmission through rib stiffened double-panel structure

    NASA Astrophysics Data System (ADS)

    Ma, Xiyue; Chen, Kean; Ding, Shaohu; Yu, Haoxin

    2016-06-01

    This paper presents an analytical investigation on physical mechanisms of actively controlling sound transmission through a rib stiffened double-panel structure using point source in the cavity. The combined modal expansion and vibro-acoustic coupling methods are applied to establish the theoretical model of such active structure. Under the condition of minimizing radiated power of the radiating ribbed plate, the physical mechanisms are interpreted in detail from the point of view of modal couplings similar as that used in existed literatures. Results obtained demonstrate that the rule of sound energy transmission and the physical mechanisms for the rib stiffened double-panel structure are all changed, and affected by the coupling effects of the rib when compared with the analytical results obtained for unribbed double-panel case. By taking the coupling effects of the rib into considerations, the cavity modal suppression and rearrangement mechanisms obtained in existed investigations are modified and supplemented for the ribbed plate case, which gives a clear interpretation for the physical nature involved in the active rib stiffened double-panel structure.

  1. Numerical investigation of sound transmission through double wall cylinders with respect to active noise control

    NASA Astrophysics Data System (ADS)

    Coats, T. J.; Silcox, R. J.; Lester, H. C.

    Market pressure for more fuel efficient air travel has led to increased use of turboprop and higher bypass turbofan engines. The low frequency components of propeller, jet and boundary layer noise are difficult to attenuate with conventional passive techniques. Weight and geometric restrictions for sound absorbing meterials limit the amount and type of treatment that may be applied. An active noise control (ANC) method is providing to be an attractive alternative. The approach taken in this paper uses a numerical finite/boundary element method (FEM/BEM) that may be easilty adapted to arbitrary geometries. A double walled cylinder is modeled using commercially available software. The outer shell is modeled as an aluminum cylinder, similar to that of aircraft skins. The inner shell is modeled as a composite material representative of a lightweight, stiff trim panel. Two different inner shell materials are used. The first is representative of current trim structure, the second a much stiffer composite. The primary source is generated by an exterior acoustic monopole. Control fields are generated using normal force inputs to the inner cylindrical shell. A linear least mean square (LMS) algorithm is used to determine amplitudes of control forces that minimize the interior acoustic field. Coupling of acoustic and structural modes and noise reductions are discussed for each of the inner shell materials.

  2. Hybrid Active/Passive Control of Sound Radiation from Panels with Constrained Layer Damping and Model Predictive Feedback Control

    NASA Technical Reports Server (NTRS)

    Cabell, Randolph H.; Gibbs, Gary P.

    2000-01-01

    make the controller adaptive. For example, a mathematical model of the plant could be periodically updated as the plant changes, and the feedback gains recomputed from the updated model. To be practical, this approach requires a simple plant model that can be updated quickly with reasonable computational requirements. A recent paper by the authors discussed one way to simplify a feedback controller, by reducing the number of actuators and sensors needed for good performance. The work was done on a tensioned aircraft-style panel excited on one side by TBL flow in a low speed wind tunnel. Actuation was provided by a piezoelectric (PZT) actuator mounted on the center of the panel. For sensing, the responses of four accelerometers, positioned to approximate the response of the first radiation mode of the panel, were summed and fed back through the controller. This single input-single output topology was found to have nearly the same noise reduction performance as a controller with fifteen accelerometers and three PZT patches. This paper extends the previous results by looking at how constrained layer damping (CLD) on a panel can be used to enhance the performance of the feedback controller thus providing a more robust and efficient hybrid active/passive system. The eventual goal is to use the CLD to reduce sound radiation at high frequencies, then implement a very simple, reduced order, low sample rate adaptive controller to attenuate sound radiation at low frequencies. Additionally this added damping smoothes phase transitions over the bandwidth which promotes robustness to natural frequency shifts. Experiments were conducted in a transmission loss facility on a clamped-clamped aluminum panel driven on one side by a loudspeaker. A generalized predictive control (GPC) algorithm, which is suited to online adaptation of its parameters, was used in single input-single output and multiple input-single output configurations. Because this was a preliminary look at the potential

  3. Active Control of Environmental Noise, Vi: Performance of a Fundamental Free-Field Sound Cancelling System

    NASA Astrophysics Data System (ADS)

    WRIGHT, S. E.; ATMOKO, H.

    2001-08-01

    Before the adaptive cancellation performance of multichannel free-field acoustic systems could be evaluated in detail, it was considered prudent to establish first the performance of a single channel free-field cancelling system. The adaptive theory for this basic system, including the stability process, is described. Measured adaptive performance is given confirming the theory.The concept of stability bands and their prediction is considered. The bands are a consequence of phase differences between the primary source and secondary cancelling field, generated by the transfer functions of the control system. At the edge of these stability bands satellite pole frequencies “beat” with the cancelling frequency, generated by the zeros, to produce side bands. The relation between the stability bandwidth and the adaptive speed, in terms of reference signal strength and adaptive step size, are investigated.The sound generation and cancellation performance of this basic canceller are then considered. The acoustic sound field directivity characteristics are similar to that of a dipole, tripole or quadrupole type source, depending on the primary-secondary source separation distance. The acoustic shadow characteristics are established in detail and compared with measurement. Good agreement is obtained.

  4. Reduction of the Radiating Sound of a Submerged Finite Cylindrical Shell Structure by Active Vibration Control

    PubMed Central

    Kim, Heung Soo; Sohn, Jung Woo; Jeon, Juncheol; Choi, Seung-Bok

    2013-01-01

    In this work, active vibration control of an underwater cylindrical shell structure was investigated, to suppress structural vibration and structure-borne noise in water. Finite element modeling of the submerged cylindrical shell structure was developed, and experimentally evaluated. Modal reduction was conducted to obtain the reduced system equation for the active feedback control algorithm. Three Macro Fiber Composites (MFCs) were used as actuators and sensors. One MFC was used as an exciter. The optimum control algorithm was designed based on the reduced system equations. The active control performance was then evaluated using the lab scale underwater cylindrical shell structure. Structural vibration and structure-borne noise of the underwater cylindrical shell structure were reduced significantly by activating the optimal controller associated with the MFC actuators. The results provide that active vibration control of the underwater structure is a useful means to reduce structure-borne noise in water. PMID:23389344

  5. Sound, Noise, and Vibration Control.

    ERIC Educational Resources Information Center

    Yerges, Lyle F.

    This working guide on the principles and techniques of controlling acoustical environment is discussed in the light of human, environmental and building needs. The nature of sound and its variables are defined. The acoustical environment and its many materials, spaces and functional requirements are described, with specific methods for planning,…

  6. Structural sensing of interior sound for active control of noise in structural-acoustic cavities.

    PubMed

    Bagha, Ashok K; Modak, S V

    2015-07-01

    This paper proposes a method for structural sensing of acoustic potential energy for active control of noise in a structural-acoustic cavity. The sensing strategy aims at global control and works with a fewer number of sensors. It is based on the established concept of radiation modes and hence does not add too many states to the order of the system. Acoustic potential energy is sensed using a combination of a Kalman filter and a frequency weighting filter with the structural response measurements as the inputs. The use of Kalman filter also makes the system robust against measurement noise. The formulation of the strategy is presented using finite element models of the system including that of sensors and actuators so that it can be easily applied to practical systems. The sensing strategy is numerically evaluated in the framework of Linear Quadratic Gaussian based feedback control of interior noise in a rectangular box cavity with a flexible plate with single and multiple pairs of piezoelectric sensor-actuator patches when broadband disturbances act on the plate. The performance is compared with an "acoustic filter" that models the complete transfer function from the structure to the acoustic domain. The sensing performance is also compared with a direct estimation strategy.

  7. Experimental Simulation of Active Control With On-line System Identification on Sound Transmission Through an Elastic Plate

    NASA Technical Reports Server (NTRS)

    1998-01-01

    An adaptive control algorithm with on-line system identification capability has been developed. One of the great advantages of this scheme is that an additional system identification mechanism such as an additional uncorrelated random signal generator as the source of system identification is not required. A time-varying plate-cavity system is used to demonstrate the control performance of this algorithm. The time-varying system consists of a stainless-steel plate which is bolted down on a rigid cavity opening where the cavity depth was changed with respect to time. For a given externally located harmonic sound excitation, the system identification and the control are simultaneously executed to minimize the transmitted sound in the cavity. The control performance of the algorithm is examined for two cases. First, all the water was drained, the external disturbance frequency is swept with 1 Hz/sec. The result shows an excellent frequency tracking capability with cavity internal sound suppression of 40 dB. For the second case, the water level is initially empty and then raised to 3/20 full in 60 seconds while the external sound excitation is fixed with a frequency. Hence, the cavity resonant frequency decreases and passes the external sound excitation frequency. The algorithm shows 40 dB transmitted noise suppression without compromising the system identification tracking capability.

  8. Piezoelectric actuator models for active sound and vibration control of cylinders

    NASA Technical Reports Server (NTRS)

    Lester, Harold C.; Lefebvre, Sylvie

    1993-01-01

    Analytical models for piezoelectric actuators, adapted from flat plate concepts, are developed for noise and vibration control applications associated with vibrating circular cylinders. The loadings applied to the cylinder by the piezoelectric actuators for the bending and in-plane force models are approximated by line moment and line force distributions, respectively, acting on the perimeter of the actuator patch area. Coupling between the cylinder and interior acoustic cavity is examined by studying the modal spectra, particularly for the low-order cylinder modes that couple efficiently with the cavity at low frequencies. Within the scope of this study, the in-plane force model produced a more favorable distribution of low-order modes, necessary for efficient interior noise control, than did the bending model.

  9. Acoustics: Motion controlled by sound

    NASA Astrophysics Data System (ADS)

    Neild, Adrian

    2016-09-01

    A simple technique has been developed that produces holograms made of sound waves. These acoustic landscapes are used to manipulate microscale objects, and offer great potential in medical imaging and selective heating. See Letter p.518

  10. Active sound attenuation across a double wall structure

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Shepherd, Kevin P.

    1991-01-01

    The possibility of achieving significant local and global sound attenuation across a flat double wall is demonstrated. It is also shown that sound can be prevented from entering the interior of a cabinlike environment. The approach used is unlike established active noise control techniques.

  11. Effect of realistic grounds and atmospheric conditions on single-channel active control of outdoor sound propagation

    NASA Astrophysics Data System (ADS)

    Nakashima, Ann; Hodgson, Murray

    2005-03-01

    Engine run-up tests are a part of routine aircraft maintenance at the Vancouver International Airport. A source of noise complaints is the Dash-8 aircraft, which emits low-frequency, tonal noise. Active noise control is a potentially cost-effective alternative to passive noise-control methods, which are ineffective at controlling low-frequency noise. Since the run-up tests are performed outdoors, the effects of outdoor conditions on the performance of an active control system must be considered. In this paper, the results of a preliminary investigation of the effects of realistic meteorological conditions and ground impedance on the performance of a single-channel active-control system are presented. Computer simulations of single-channel active control of a monopole source were performed using the Green's-function parabolic-equation method. Different realistic atmospheric conditions, and reflective or soft ground, were used in the simulations. The results show that atmospheric refraction causes fluctuations in the noise attenuation achieved by a single-channel control system, and has the overall effect of decreasing its performance, making the system ineffective in some cases. .

  12. Robust Feedback Control of Flow Induced Structural Radiation of Sound

    NASA Technical Reports Server (NTRS)

    Heatwole, Craig M.; Bernhard, Robert J.; Franchek, Matthew A.

    1997-01-01

    A significant component of the interior noise of aircraft and automobiles is a result of turbulent boundary layer excitation of the vehicular structure. In this work, active robust feedback control of the noise due to this non-predictable excitation is investigated. Both an analytical model and experimental investigations are used to determine the characteristics of the flow induced structural sound radiation problem. The problem is shown to be broadband in nature with large system uncertainties associated with the various operating conditions. Furthermore the delay associated with sound propagation is shown to restrict the use of microphone feedback. The state of the art control methodologies, IL synthesis and adaptive feedback control, are evaluated and shown to have limited success for solving this problem. A robust frequency domain controller design methodology is developed for the problem of sound radiated from turbulent flow driven plates. The control design methodology uses frequency domain sequential loop shaping techniques. System uncertainty, sound pressure level reduction performance, and actuator constraints are included in the design process. Using this design method, phase lag was added using non-minimum phase zeros such that the beneficial plant dynamics could be used. This general control approach has application to lightly damped vibration and sound radiation problems where there are high bandwidth control objectives requiring a low controller DC gain and controller order.

  13. 75 FR 77047 - Statement on Sound Practices Concerning Elevated Risk Complex Structured Finance Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-10

    ... Office of Thrift Supervision Statement on Sound Practices Concerning Elevated Risk Complex Structured.... Title of Proposal: Statement on Sound Practices Concerning Elevated Risk Complex Structured Finance... Elevated Risk Complex Structured Finance Activities describes the types of internal controls and...

  14. Modular and Adaptive Control of Sound Processing

    NASA Astrophysics Data System (ADS)

    van Nort, Douglas

    This dissertation presents research into the creation of systems for the control of sound synthesis and processing. The focus differs from much of the work related to digital musical instrument design, which has rightly concentrated on the physicality of the instrument and interface: sensor design, choice of controller, feedback to performer and so on. Often times a particular choice of sound processing is made, and the resultant parameters from the physical interface are conditioned and mapped to the available sound parameters in an exploratory fashion. The main goal of the work presented here is to demonstrate the importance of the space that lies between physical interface design and the choice of sound manipulation algorithm, and to present a new framework for instrument design that strongly considers this essential part of the design process. In particular, this research takes the viewpoint that instrument designs should be considered in a musical control context, and that both control and sound dynamics must be considered in tandem. In order to achieve this holistic approach, the work presented in this dissertation assumes complementary points of view. Instrument design is first seen as a function of musical context, focusing on electroacoustic music and leading to a view on gesture that relates perceived musical intent to the dynamics of an instrumental system. The important design concept of mapping is then discussed from a theoretical and conceptual point of view, relating perceptual, systems and mathematically-oriented ways of examining the subject. This theoretical framework gives rise to a mapping design space, functional analysis of pertinent existing literature, implementations of mapping tools, instrumental control designs and several perceptual studies that explore the influence of mapping structure. Each of these reflect a high-level approach in which control structures are imposed on top of a high-dimensional space of control and sound synthesis

  15. Emotion and identification of environmental sounds and electroencephalographic activity.

    PubMed

    Shimai, S

    1992-06-01

    Eight environmental sounds, i.e., playing the harp, cuckoo's song, sound of the waves, cock's crow, noise of the subway, alarm of a clock, sound of a dentist's drill, scratching of the blackboard, and their temporally reverse sounds were presented for 20 sec to 16 college students in a sound-attenuated chamber. The subjects were requested to estimate the degree of pleasantness-unpleasantness and confidence in identifying each sound 10 sec after presentation. Electroencephalography was recorded at C3, C4, O1 and O2 (International 10-20 system), and the mean EEG powers of delta, theta, alpha-1, alpha-2, beta-1 and beta-2 bands during the sound presentations were computed by a signal processor. The results were as follows: 1) Even when the loudness and frequency component of the sounds were equivalent, there was big difference in pleasantness-unpleasantness estimation among the environmental sounds. 2) Inaccuracy in identifying the sounds presented backwards neutralized the pleasantness-unpleasantness estimation. 3) Powers of theta and low frequency alpha bands were higher during presentation of the pleasant sounds than during presentation of the unpleasant sounds. 4) Alpha activity was more closely related with subjective confidence in sound identification than with pleasantness-unpleasantness estimation of sound. These findings suggest that pleasantness-unpleasantness estimation of environmental sounds depends not only on their loudness level or frequency component but on the accuracy in sound identification and that modification of sound identification may be useful in alleviating the environment noise problem. Alpha activity seems to be closely related to the recognition of sound, but further research is needed on EEG activity in the relationship between the emotional state and sound identification.

  16. Brain activation during anticipation of sound sequences.

    PubMed

    Leaver, Amber M; Van Lare, Jennifer; Zielinski, Brandon; Halpern, Andrea R; Rauschecker, Josef P

    2009-02-25

    Music consists of sound sequences that require integration over time. As we become familiar with music, associations between notes, melodies, and entire symphonic movements become stronger and more complex. These associations can become so tight that, for example, hearing the end of one album track can elicit a robust image of the upcoming track while anticipating it in total silence. Here, we study this predictive "anticipatory imagery" at various stages throughout learning and investigate activity changes in corresponding neural structures using functional magnetic resonance imaging. Anticipatory imagery (in silence) for highly familiar naturalistic music was accompanied by pronounced activity in rostral prefrontal cortex (PFC) and premotor areas. Examining changes in the neural bases of anticipatory imagery during two stages of learning conditional associations between simple melodies, however, demonstrates the importance of fronto-striatal connections, consistent with a role of the basal ganglia in "training" frontal cortex (Pasupathy and Miller, 2005). Another striking change in neural resources during learning was a shift between caudal PFC earlier to rostral PFC later in learning. Our findings regarding musical anticipation and sound sequence learning are highly compatible with studies of motor sequence learning, suggesting common predictive mechanisms in both domains. PMID:19244522

  17. Issues in Humanoid Audition and Sound Source Localization by Active Audition

    NASA Astrophysics Data System (ADS)

    Nakadai, Kazuhiro; Okuno, Hiroshi G.; Kitano, Hiroaki

    In this paper, we present an active audition system which is implemented on the humanoid robot "SIG the humanoid". The audition system for highly intelligent humanoids localizes sound sources and recognizes auditory events in the auditory scene. Active audition reported in this paper enables SIG to track sources by integrating audition, vision, and motor movements. Given the multiple sound sources in the auditory scene, SIG actively moves its head to improve localization by aligning microphones orthogonal to the sound source and by capturing the possible sound sources by vision. However, such an active head movement inevitably creates motor noises.The system adaptively cancels motor noises using motor control signals and the cover acoustics. The experimental result demonstrates that active audition by integration of audition, vision, and motor control attains sound source tracking in variety of conditions.onditions.

  18. Motor area activity for action-related and nonaction-related sounds in a three-dimensional sound field reproduction system.

    PubMed

    Tsuchida, Koichiro; Ueno, Kanako; Shimada, Sotaro

    2015-03-25

    The motor cortical area is often activated to auditory stimuli in the human brain. In this study, we examined whether the motor area shows differential activation for action-related and nonaction-related sounds and whether it is susceptible to the quality of the sounds. A three-dimensional sound field recording and reproduction system based on the boundary surface control principle (BoSC system) was used for this purpose. We measured brain activity during hearing action-related or nonaction-related sounds with electroencephalography using mu rhythm suppression (mu-suppression) as an index of motor cortical activation. The results showed that mu-suppression was observed when the participant heard action-related sounds, but it was not evident when hearing nonaction-related sounds. Moreover, this suppression was significantly larger in the 3D sound field (62-ch loudspeaker condition), which generates a more realistic sound field, than in the 1-ch loudspeaker condition. Our results indicate that the motor area was indeed activated for action-related sounds and that its activation was enhanced with a 3D realistic sound field. We discuss our findings in relation to the mirror neuron system and the possibility of using its activity as an objective measure that reflects the subjective sense of reality in various virtual reality settings when interacting with others.

  19. Study of Vertical Sound Image Control Using Parametric Loudspeakers

    NASA Astrophysics Data System (ADS)

    Shimizu, Kazuhiro; Itou, Kouki; Aoki, Shigeaki

    A parametric loudspeaker is known as a super-directivity loudspeaker. So far, the applications have been limited monaural reproduction sound system. We had discussed characteristics of stereo reproduction with two parametric loudspeakers. In this paper, the sound localization in the vertical direction using the parametric loudspeakers was confirmed. The direction of sound localization was able to be controlled. The results were similar as in using ordinary loudspeakers. However, by setting the parametric loudspeaker 5 degrees rightward, the direction of sound localization moved about 20 degrees rightward. The measured ILD (Interaural Level Difference) using a dummy head were analyzed.

  20. Mathematically trivial control of sound using a parametric beam focusing source.

    PubMed

    Tanaka, Nobuo; Tanaka, Motoki

    2011-01-01

    By exploiting a case regarded as trivial, this paper presents global active noise control using a parametric beam focusing source (PBFS). As with a dipole model, one is used for a primary sound source and the other for a control sound source, the control effect for minimizing a total acoustic power depends on the distance between the two. When the distance becomes zero, the total acoustic power becomes null, hence nothing less than a trivial case. Because of the constraints in practice, there exist difficulties in placing a control source close enough to a primary source. However, by projecting a sound beam of a parametric array loudspeaker onto the target sound source (primary source), a virtual sound source may be created on the target sound source, thereby enabling the collocation of the sources. In order to further ensure feasibility of the trivial case, a PBFS is then introduced in an effort to meet the size of the two sources. Reflected sound wave of the PBFS, which is tantamount to the virtual sound source output, aims to suppress the primary sound. Finally, a numerical analysis as well as an experiment is conducted, verifying the validity of the proposed methodology. PMID:21302999

  1. Commissural Gain Control Enhances the Midbrain Representation of Sound Location

    PubMed Central

    Orton, Llwyd David; Papasavvas, Christoforos A.

    2016-01-01

    Accurate localization of sound sources is essential for survival behavior in many species. The inferior colliculi (ICs) are the first point in the auditory pathway where cues used to locate sounds, ie, interaural time differences (ITDs), interaural level differences (ILDs), and pinna spectral cues, are all represented in the same location. These cues are first extracted separately on each side of the midline in brainstem nuclei that project to the ICs. Because of this segregation, each IC predominantly represents stimuli in the contralateral hemifield. We tested the hypothesis that commissural connections between the ICs mediate gain control that enhances sound localization acuity. We recorded IC neurons sensitive to either ITDs or ILDs in anesthetized guinea pig, before, during, and following recovery from deactivation of the contralateral IC by cryoloop cooling or microdialysis of procaine. During deactivation, responses were rescaled by divisive gain change and additive shifts, which reduced the dynamic range of ITD and ILD response functions and the ability of neurons to signal changes in sound location. These data suggest that each IC exerts multiplicative gain control and subtractive shifts over the other IC that enhances the neural representation of sound location. Furthermore, this gain control operates in a similar manner on both ITD- and ILD-sensitive neurons, suggesting a shared mechanism operates across localization cues. Our findings reveal a novel dependence of sound localization on commissural processing. SIGNIFICANCE STATEMENT Sound localization, a fundamental process in hearing, is dependent on bilateral computations in the brainstem. How this information is transmitted from the brainstem to the auditory cortex, through several stages of processing, without loss of signal fidelity, is not clear. We show that the ability of neurons in the auditory midbrain to encode azimuthal sound location is dependent on gain control mediated by the commissure of

  2. Peripheral sounds rapidly activate visual cortex: evidence from electrocorticography.

    PubMed

    Brang, David; Towle, Vernon L; Suzuki, Satoru; Hillyard, Steven A; Di Tusa, Senneca; Dai, Zhongtian; Tao, James; Wu, Shasha; Grabowecky, Marcia

    2015-11-01

    Neurophysiological studies with animals suggest that sounds modulate activity in primary visual cortex in the presence of concurrent visual stimulation. Noninvasive neuroimaging studies in humans have similarly shown that sounds modulate activity in visual areas even in the absence of visual stimuli or visual task demands. However, the spatial and temporal limitations of these noninvasive methods prevent the determination of how rapidly sounds activate early visual cortex and what information about the sounds is relayed there. Using spatially and temporally precise measures of local synaptic activity acquired from depth electrodes in humans, we demonstrate that peripherally presented sounds evoke activity in the anterior portion of the contralateral, but not ipsilateral, calcarine sulcus within 28 ms of sound onset. These results suggest that auditory stimuli rapidly evoke spatially specific activity in visual cortex even in the absence of concurrent visual stimulation or visual task demands. This rapid auditory-evoked activation of primary visual cortex is likely to be mediated by subcortical pathways or direct cortical projections from auditory to visual areas. PMID:26334017

  3. Decentralized Control of Sound Radiation using a High-Authority/Low-Authority Control Strategy with Anisotropic Actuators

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Cabell, Randolph H.; Fuller, Chris R.

    2008-01-01

    This paper describes a combined control strategy designed to reduce sound radiation from stiffened aircraft-style panels. The control architecture uses robust active damping in addition to high-authority linear quadratic Gaussian (LQG) control. Active damping is achieved using direct velocity feedback with triangularly shaped anisotropic actuators and point velocity sensors. While active damping is simple and robust, stability is guaranteed at the expense of performance. Therefore the approach is often referred to as low-authority control. In contrast, LQG control strategies can achieve substantial reductions in sound radiation. Unfortunately, the unmodeled interaction between neighboring control units can destabilize decentralized control systems. Numerical simulations show that combining active damping and decentralized LQG control can be beneficial. In particular, augmenting the in-bandwidth damping supplements the performance of the LQG control strategy and reduces the destabilizing interaction between neighboring control units.

  4. Decentralized Control of Sound Radiation Using Iterative Loop Recovery

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Cabell, Randolph H.; Fuller, Chris R.

    2009-01-01

    A decentralized model-based control strategy is designed to reduce low-frequency sound radiation from periodically stiffened panels. While decentralized control systems tend to be scalable, performance can be limited due to modeling error introduced by the unmodeled interaction between neighboring control units. Since bounds on modeling error are not known in advance, it is difficult to ensure the decentralized control system will be robust without making the controller overly conservative. Therefore an iterative approach is suggested, which utilizes frequency-shaped loop recovery. The approach accounts for modeling error introduced by neighboring control loops, requires no communication between subsystems, and is relatively simple. The control strategy is evaluated numerically using a model of a stiffened aluminum panel that is representative of the sidewall of an aircraft. Simulations demonstrate that the iterative approach can achieve significant reductions in radiated sound power from the stiffened panel without destabilizing neighboring control units.

  5. Decentralized control of sound radiation using iterative loop recovery.

    PubMed

    Schiller, Noah H; Cabell, Randolph H; Fuller, Chris R

    2010-10-01

    A decentralized model-based control strategy is designed to reduce low-frequency sound radiation from periodically stiffened panels. While decentralized control systems tend to be scalable, performance can be limited due to modeling error introduced by the unmodeled interaction between neighboring control units. Since bounds on modeling error are not known in advance, it is difficult to ensure the decentralized control system will be robust without making the controller overly conservative. Therefore an iterative approach is suggested, which utilizes frequency-shaped loop recovery. The approach accounts for modeling error introduced by neighboring control loops, requires no communication between subsystems, and is relatively simple. The control strategy is evaluated numerically using a model of a stiffened aluminum panel that is representative of the sidewall of an aircraft. Simulations demonstrate that the iterative approach can achieve significant reductions in radiated sound power from the stiffened panel without destabilizing neighboring control units.

  6. Decentralized control of sound radiation using iterative loop recovery.

    PubMed

    Schiller, Noah H; Cabell, Randolph H; Fuller, Chris R

    2010-10-01

    A decentralized model-based control strategy is designed to reduce low-frequency sound radiation from periodically stiffened panels. While decentralized control systems tend to be scalable, performance can be limited due to modeling error introduced by the unmodeled interaction between neighboring control units. Since bounds on modeling error are not known in advance, it is difficult to ensure the decentralized control system will be robust without making the controller overly conservative. Therefore an iterative approach is suggested, which utilizes frequency-shaped loop recovery. The approach accounts for modeling error introduced by neighboring control loops, requires no communication between subsystems, and is relatively simple. The control strategy is evaluated numerically using a model of a stiffened aluminum panel that is representative of the sidewall of an aircraft. Simulations demonstrate that the iterative approach can achieve significant reductions in radiated sound power from the stiffened panel without destabilizing neighboring control units. PMID:20968346

  7. Inaudible high-frequency sounds affect brain activity: hypersonic effect.

    PubMed

    Oohashi, T; Nishina, E; Honda, M; Yonekura, Y; Fuwamoto, Y; Kawai, N; Maekawa, T; Nakamura, S; Fukuyama, H; Shibasaki, H

    2000-06-01

    Although it is generally accepted that humans cannot perceive sounds in the frequency range above 20 kHz, the question of whether the existence of such "inaudible" high-frequency components may affect the acoustic perception of audible sounds remains unanswered. In this study, we used noninvasive physiological measurements of brain responses to provide evidence that sounds containing high-frequency components (HFCs) above the audible range significantly affect the brain activity of listeners. We used the gamelan music of Bali, which is extremely rich in HFCs with a nonstationary structure, as a natural sound source, dividing it into two components: an audible low-frequency component (LFC) below 22 kHz and an HFC above 22 kHz. Brain electrical activity and regional cerebral blood flow (rCBF) were measured as markers of neuronal activity while subjects were exposed to sounds with various combinations of LFCs and HFCs. None of the subjects recognized the HFC as sound when it was presented alone. Nevertheless, the power spectra of the alpha frequency range of the spontaneous electroencephalogram (alpha-EEG) recorded from the occipital region increased with statistical significance when the subjects were exposed to sound containing both an HFC and an LFC, compared with an otherwise identical sound from which the HFC was removed (i.e., LFC alone). In contrast, compared with the baseline, no enhancement of alpha-EEG was evident when either an HFC or an LFC was presented separately. Positron emission tomography measurements revealed that, when an HFC and an LFC were presented together, the rCBF in the brain stem and the left thalamus increased significantly compared with a sound lacking the HFC above 22 kHz but that was otherwise identical. Simultaneous EEG measurements showed that the power of occipital alpha-EEGs correlated significantly with the rCBF in the left thalamus. Psychological evaluation indicated that the subjects felt the sound containing an HFC to be more

  8. Transparent sound screens. [and their noise control efficiency in buildings

    NASA Technical Reports Server (NTRS)

    Bizo, F.; Draghici, R.

    1974-01-01

    Transparent sound screens consisting of glass (organic glass) plates placed at fixed angles with respect to the floor are considered. Noise levels in the screened area depend on the cumulative effect of direct, reverberated and refracted components of sound energy radiated by the source. This effect is analyzed on the analogy of the summation of electrical impedances. Inasmuch as under given circumstances sufficient noise control can be obtained, transparent screens seem to solve the problem of unimpeded supervision of installations in noisy workshops and power plants; in administrative buildings, computing centers, design bureaus, etc., they ensure acoustic comfort without space losses and without inspiring claustrophobia.

  9. Controlled sound field with a dual layer loudspeaker array

    NASA Astrophysics Data System (ADS)

    Shin, Mincheol; Fazi, Filippo M.; Nelson, Philip A.; Hirono, Fabio C.

    2014-08-01

    Controlled sound interference has been extensively investigated using a prototype dual layer loudspeaker array comprised of 16 loudspeakers. Results are presented for measures of array performance such as input signal power, directivity of sound radiation and accuracy of sound reproduction resulting from the application of conventional control methods such as minimization of error in mean squared pressure, maximization of energy difference and minimization of weighted pressure error and energy. Procedures for selecting the tuning parameters have also been introduced. With these conventional concepts aimed at the production of acoustically bright and dark zones, all the control methods used require a trade-off between radiation directivity and reproduction accuracy in the bright zone. An alternative solution is proposed which can achieve better performance based on the measures presented simultaneously by inserting a low priority zone named as the “gray” zone. This involves the weighted minimization of mean-squared errors in both bright and dark zones together with the gray zone in which the minimization error is given less importance. This results in the production of directional bright zone in which the accuracy of sound reproduction is maintained with less required input power. The results of simulations and experiments are shown to be in excellent agreement.

  10. Regarding "Semi-active control of the rocking motion of monolithic art objects" [Journal of Sound and Vibration, 374 (2016) 1-16

    NASA Astrophysics Data System (ADS)

    Cartmell, Matthew P.

    2016-09-01

    The Editor wishes to make the reader aware that the paper "Semi-active control of the rocking motion of monolithic art objects" by R. Ceravolo, M.L. Pecorelli, and L.Z. Fragonara, did not contain a direct citation of the fundamental and original work by D. Konstantinidis and N. Makris entitled "Experimental and analytical studies on the seismic response of free-standing and anchored laboratory equipment", Report No. PEER 2005/07. Pacific Earthquake Engineering Research (PEER) Center, University of California, Berkeley, 2005. The Editor regrets that this omission was not noted at the time that the above paper was accepted and published.

  11. Decentralized harmonic control of sound radiation and transmission by a plate using a virtual impedance approach.

    PubMed

    Quaegebeur, Nicolas; Micheau, Philippe; Berry, Alain

    2009-05-01

    The problem under study in this article is the active control of sound transmission and radiation of a panel under a periodic excitation. The control strategy investigated uses independent control loops between an individual polyvinylidene fluoride (PVDF) sensor and an individual lead zirconate titanate (PZT) actuator. The specific approach employed here uses the concept of virtual impedance. The aim is to determine for each frequency the optimal impedance between each PVDF sensor and the corresponding PZT actuator in order to reduce the sound power radiated by the plate. Theoretical predictions are compared to measurements of the sound radiated and transmission loss of a panel mounted with eight PZT-PVDF units. Reductions of up to 20 dB of the acoustic power can be achieved around mechanical resonances of the system, while the control strategy has little effect for off-resonance excitations.

  12. DETECTION AND IDENTIFICATION OF SPEECH SOUNDS USING CORTICAL ACTIVITY PATTERNS

    PubMed Central

    Centanni, T.M.; Sloan, A.M.; Reed, A.C.; Engineer, C.T.; Rennaker, R.; Kilgard, M.P.

    2014-01-01

    We have developed a classifier capable of locating and identifying speech sounds using activity from rat auditory cortex with an accuracy equivalent to behavioral performance without the need to specify the onset time of the speech sounds. This classifier can identify speech sounds from a large speech set within 40 ms of stimulus presentation. To compare the temporal limits of the classifier to behavior, we developed a novel task that requires rats to identify individual consonant sounds from a stream of distracter consonants. The classifier successfully predicted the ability of rats to accurately identify speech sounds for syllable presentation rates up to 10 syllables per second (up to 17.9 ± 1.5 bits/sec), which is comparable to human performance. Our results demonstrate that the spatiotemporal patterns generated in primary auditory cortex can be used to quickly and accurately identify consonant sounds from a continuous speech stream without prior knowledge of the stimulus onset times. Improved understanding of the neural mechanisms that support robust speech processing in difficult listening conditions could improve the identification and treatment of a variety of speech processing disorders. PMID:24286757

  13. Sound

    NASA Astrophysics Data System (ADS)

    Capstick, J. W.

    2013-01-01

    1. The nature of sound; 2. Elasticity and vibrations; 3. Transverse waves; 4. Longitudinal waves; 5. Velocity of longitudinal waves; 6. Reflection and refraction. Doppler's principle; 7. Interference. Beats. Combination tones; 8. Resonance and forced vibrations; 9. Quality of musical notes; 10. Organ pipes; 11. Rods. Plates. Bells; 12. Acoustical measurements; 13. The phonograph, microphone and telephone; 14. Consonance; 15. Definition of intervals. Scales. Temperament; 16. Musical instruments; 17. Application of acoustical principles to military purposes; Questions; Answers to questions; Index.

  14. Active noise control of a vibrating surface: Continuum and non-continuum investigations on vibroacoustic sound reduction by a secondary heat-flux source

    NASA Astrophysics Data System (ADS)

    Manela, A.; Pogorelyuk, L.

    2015-12-01

    We study the effect of surface heating on sound radiation by a vibrating boundary. Focusing on a setup of an infinite planar wall interacting with a semi-infinite expanse of a gas, the system response to arbitrary (small-amplitude) vibro-thermal excitation is investigated. Starting with the case of sinusoidal actuations, the superposed effect of boundary heat-flux excitation at a common frequency ω is examined. The entire range of frequencies is considered, where, depending on the ratio between ω and gas kinetic collision frequency ωcoll, fundamentally different flow regimes follow. The two limit cases of ω ≪ωcoll (continuum-flow conditions) and ω ≫ωcoll (ballistic flow regime) are investigated analytically, based on continuum equations and collisionless Boltzmann equation, respectively. In between, an intermediate interval of frequencies ω ~ωcoll is analyzed numerically, based on the direct simulation Monte Carlo method. In search for optimal conditions for acoustic sound reduction, it is found that effective attenuation is obtained when boundary heat flux is applied at opposite phase to surface actuation. Amplitude-wise, conditions for minimization of the acoustic field vary between the limits: at low-frequency conditions, wave radiation extends over large distances from the wall, and optimal sound reduction is achieved when the ratio between wall-inserted thermal and kinetic energies |Eq/Ek|opt equals γ /(γ - 1) (with γ denoting the ratio between gas specific heat capacities). At high-frequency conditions, wall signal affects only a thin gas layer (of the order of the mean free path) in the vicinity of the boundary, and optimal attenuation is achieved when |Eq/Ek|opt = 1. The analysis is extended to consider the system response to non-periodic excitations, for the specific case of a delta-function input. Making use of the above collisionless- and continuum-limit analyses, early- and late-time system responses are computed. While conditions for

  15. Annoyance resulting from intrusion of aircraft sounds upon various activities

    NASA Technical Reports Server (NTRS)

    Gunn, W. J.; Shepherd, W. T.; Fletcher, J. L.

    1975-01-01

    An experiment was conducted in which subjects were engaged in TV viewing, telephone listening, or reverie (no activity) for a 1/2-hour session. During the session, they were exposed to a series of recorded aircraft sounds at the rate of one flight every 2 minutes. Within each session, four levels of flyover noise, separated by dB increments, were presented several times in a Latin Square balanced sequence. The peak level of the noisiest flyover in any session was fixed at 95, 90, 85, 75, or 70 dBA. At the end of the test session, subjects recorded their responses to the aircraft sounds, using a bipolar scale which covered the range from very pleasant to extremely annoying. Responses to aircraft noises were found to be significantly affected by the particular activity in which the subjects were engaged. Not all subjects found the aircraft sounds to be annoying.

  16. 76 FR 34627 - Proposed Modification of Offshore Airspace Areas: Norton Sound Low, Control 1234L and Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-14

    ... Areas: Norton Sound Low, Control 1234L and Control 1487L; Alaska AGENCY: Federal Aviation Administration... Sound Low, Control 1234L, and Control 1487L Offshore Airspace Areas in Alaska. The airspace floors would... Norton Sound Low, Control 1234L, and Control 1487L Offshore Airspace Areas in Alaska. The Norton...

  17. Adaptive wave field synthesis for active sound field reproduction: experimental results.

    PubMed

    Gauthier, Philippe-Aubert; Berry, Alain

    2008-04-01

    Sound field reproduction has applications in music reproduction, spatial audio, sound environment reproduction, and experimental acoustics. Sound field reproduction can be used to artificially reproduce the spatial character of natural hearing. The objective is then to reproduce a sound field in a real reproduction environment. Wave field synthesis (WFS) is a known open-loop technology which assumes that the reproduction environment is anechoic. The room response thus reduces the quality of the physical sound field reproduction by WFS. In recent research papers, adaptive wave field synthesis (AWFS) was defined as a potential solution to compensate for these quality reductions from which WFS objective performance suffers. In this paper, AWFS is experimentally investigated as an active sound field reproduction system with a limited number of reproduction error sensors to compensate for the response of the listening environment. Two digital signal processing algorithms for AWFS are used for comparison purposes, one of which is based on independent radiation mode control. AWFS performed propagating sound field reproduction better than WFS in three tested reproduction spaces (hemianechoic chamber, standard laboratory space, and reverberation chamber). PMID:18397007

  18. Influence of sorption on sound propagation in granular activated carbon.

    PubMed

    Venegas, Rodolfo; Umnova, Olga

    2016-08-01

    Granular activated carbon (GAC) has numerous applications due to its ability to adsorb and desorb gas molecules. Recently, it has been shown to exhibit unusually high low frequency sound absorption. This behavior is determined by both the multi-scale nature of the material, i.e., the existence of three scales of heterogeneities, and physical processes specific to micro- and nanometer-size pores, i.e., rarefaction and sorption effects. To account for these processes a model for sound propagation in GAC is developed in this work. A methodology for characterizing GAC which includes optical granulometry, flow resistivity measurements, and the derivation of the inner-particle model parameters from acoustical and non-acoustical measurements is also presented. The model agrees with measurements of normal incidence surface impedance and sound absorption coefficient on three different GAC samples. PMID:27586708

  19. Sounding rocket activities of Japan in 2003 and 2004

    NASA Astrophysics Data System (ADS)

    Ishii, Nobuaki; Inatani, Yoshifumi; Nonaka, Satoshi; Nakajima, Takashi; Takumi, Abe; Yuichi, Tsuda; Yamagami, Takamasa

    2005-08-01

    In October 2003, a new space agency, JAXA (Japan Aerospace Exploration Agency) was reorganized and started as a primary space agency to promote all space activities in Japan. The Institute of Space and Astronautical Science (ISAS) belonged to JAXA and continued to promote space science and technologies using unique scientific satellites, sounding rockets and balloons. This paper summarizes sounding rocket and ballooning activities of ISAS in the fiscal year of 2003 and 2004, associated with satellite launch programs. In this time period, three sounding rockets and nineteen balloons were launched by ISAS. One of the sounding rocket, S-310-35 was an international collaboration between Japan and Norway, which was launched from Andoya Rocket Range (ARR), Andenes, Norway, so as to study the upper atmospheric dynamics and energetics associated with the auroral energy in the polar lower thermosphere. Through the combination with the national researchers and the cooperation with international organizations, ISAS will keep its own flight opportunities and be able to obtain many new scientific findings.

  20. Recent sounding rocket highlights and a concept for melding sounding rocket and space shuttle activities

    NASA Technical Reports Server (NTRS)

    Lane, J. H.; Mayo, E. E.

    1980-01-01

    Highlights include launching guided vehicles into the African Solar Eclipse, initiation of development of a Three-Stage Black Brant to explore the dayside polar cusp, large payload Aries Flights at White Sands Missile Range, and an active program with the Orion vehicle family using surplus motors. Sounding rocket philosophy and experience is being applied to the shuttle in a Get Away Special and Experiments of Opportunity Payloads Programs. In addition, an orbit selection and targeting software system to support shuttle pallet mounted experiments is under development.

  1. Interaction Metrics for Feedback Control of Sound Radiation from Stiffened Panels

    NASA Technical Reports Server (NTRS)

    Cabell, Randolph H.; Cox, David E.; Gibbs, Gary P.

    2003-01-01

    Interaction metrics developed for the process control industry are used to evaluate decentralized control of sound radiation from bays on an aircraft fuselage. The metrics are applied to experimentally measured frequency response data from a model of an aircraft fuselage. The purpose is to understand how coupling between multiple bays of the fuselage can destabilize or limit the performance of a decentralized active noise control system. The metrics quantitatively verify observations from a previous experiment, in which decentralized controllers performed worse than centralized controllers. The metrics do not appear to be useful for explaining control spillover which was observed in a previous experiment.

  2. Aircraft panel with sensorless active sound power reduction capabilities through virtual mechanical impedances

    NASA Astrophysics Data System (ADS)

    Boulandet, R.; Michau, M.; Micheau, P.; Berry, A.

    2016-01-01

    This paper deals with an active structural acoustic control approach to reduce the transmission of tonal noise in aircraft cabins. The focus is on the practical implementation of the virtual mechanical impedances method by using sensoriactuators instead of conventional control units composed of separate sensors and actuators. The experimental setup includes two sensoriactuators developed from the electrodynamic inertial exciter and distributed over an aircraft trim panel which is subject to a time-harmonic diffuse sound field. The target mechanical impedances are first defined by solving a linear optimization problem from sound power measurements before being applied to the test panel using a complex envelope controller. Measured data are compared to results obtained with sensor-actuator pairs consisting of an accelerometer and an inertial exciter, particularly as regards sound power reduction. It is shown that the two types of control unit provide similar performance, and that here virtual impedance control stands apart from conventional active damping. In particular, it is clear from this study that extra vibrational energy must be provided by the actuators for optimal sound power reduction, mainly due to the high structural damping in the aircraft trim panel. Concluding remarks on the benefits of using these electrodynamic sensoriactuators to control tonal disturbances are also provided.

  3. Design of virtual three-dimensional instruments for sound control

    NASA Astrophysics Data System (ADS)

    Mulder, Axel Gezienus Elith

    An environment for designing virtual instruments with 3D geometry has been prototyped and applied to real-time sound control and design. It enables a sound artist, musical performer or composer to design an instrument according to preferred or required gestural and musical constraints instead of constraints based only on physical laws as they apply to an instrument with a particular geometry. Sounds can be created, edited or performed in real-time by changing parameters like position, orientation and shape of a virtual 3D input device. The virtual instrument can only be perceived through a visualization and acoustic representation, or sonification, of the control surface. No haptic representation is available. This environment was implemented using CyberGloves, Polhemus sensors, an SGI Onyx and by extending a real- time, visual programming language called Max/FTS, which was originally designed for sound synthesis. The extension involves software objects that interface the sensors and software objects that compute human movement and virtual object features. Two pilot studies have been performed, involving virtual input devices with the behaviours of a rubber balloon and a rubber sheet for the control of sound spatialization and timbre parameters. Both manipulation and sonification methods affect the naturalness of the interaction. Informal evaluation showed that a sonification inspired by the physical world appears natural and effective. More research is required for a natural sonification of virtual input device features such as shape, taking into account possible co- articulation of these features. While both hands can be used for manipulation, left-hand-only interaction with a virtual instrument may be a useful replacement for and extension of the standard keyboard modulation wheel. More research is needed to identify and apply manipulation pragmatics and movement features, and to investigate how they are co-articulated, in the mapping of virtual object

  4. Mechanisms of transmission and control of low-frequency sound in aircraft interiors

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.

    1985-01-01

    A simplified analytical model is used to study the principal mechanisms at work in propeller noise source radiation, fuselage response, and the behavior of the coupled inner acoustic field, in order to control low frequency sound in aircraft interiors. Both active and passive methods of noise control are comparatively evaluated in light of the transmission mechanisms. Fuselage vibrational response is noted to be dominated by only a few lower order circumferential modes.

  5. Cognitive Control of Involuntary Distraction by Deviant Sounds

    ERIC Educational Resources Information Center

    Parmentier, Fabrice B. R.; Hebrero, Maria

    2013-01-01

    It is well established that a task-irrelevant sound (deviant sound) departing from an otherwise repetitive sequence of sounds (standard sounds) elicits an involuntary capture of attention and orienting response toward the deviant stimulus, resulting in the lengthening of response times in an ongoing task. Some have argued that this type of…

  6. Active Control of Environmental Noise

    NASA Astrophysics Data System (ADS)

    Wright, S. E.; Vuksanovic, B.

    1996-02-01

    Most of the current research on active noise control is confined to restricted spaces such as earphones, active silencers, air-conditioning ducts, truck cabins and aircraft fuselages. In this paper the basic concepts of environmental noise reduction by using active noise control in unconfined spaces are explored. The approach is to develop a controlled acoustic shadow, generated by a wall of secondary sources, to reduce unwanted sound in the direction of a complaint area. The basic acoustic theory is considered, followed by computer modelling, and some results to show the effectiveness of the approach. EA Technology and Yorkshire electric in the United Kingdom are supporting this work.

  7. Decoding of the sound frequency from the steady-state neural activities in rat auditory cortex.

    PubMed

    Shiramatsu, Tomoyo I; Noda, Takahiro; Kanzaki, Ryohei; Takahashi, Hirokazu

    2013-01-01

    In the auditory cortex, onset activities have been extensively investigated as a cortical representation of sound information such as sound frequency. Yet, less attention has been paid to date to steady-state activities following the onset activities. In this study, we used machine learning to investigate whether steady-state activities in the presence of continuous sounds represent the sound frequency. Sparse Logistic Regression (SLR) decoded the sound frequency from band specific power or phase locking value (PLV) of local field potentials (LFP) from the fourth layer of the auditory cortex of anesthetized rats. Consequently, we found that SLR was able to decode the sound frequency from steady-state neural activities as well as onset activities. This result demonstrates that the steady-state activities contain information about the sound such as sound frequency.

  8. 40 CFR 81.32 - Puget Sound Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Puget Sound Intrastate Air Quality Control Region. 81.32 Section 81.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Quality Control Regions § 81.32 Puget Sound Intrastate Air Quality Control Region. The Puget...

  9. 40 CFR 81.32 - Puget Sound Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Puget Sound Intrastate Air Quality Control Region. 81.32 Section 81.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Quality Control Regions § 81.32 Puget Sound Intrastate Air Quality Control Region. The Puget...

  10. 40 CFR 81.32 - Puget Sound Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Puget Sound Intrastate Air Quality Control Region. 81.32 Section 81.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Quality Control Regions § 81.32 Puget Sound Intrastate Air Quality Control Region. The Puget...

  11. 40 CFR 81.32 - Puget Sound Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Puget Sound Intrastate Air Quality Control Region. 81.32 Section 81.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Quality Control Regions § 81.32 Puget Sound Intrastate Air Quality Control Region. The Puget...

  12. 40 CFR 81.32 - Puget Sound Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Puget Sound Intrastate Air Quality Control Region. 81.32 Section 81.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Quality Control Regions § 81.32 Puget Sound Intrastate Air Quality Control Region. The Puget...

  13. Intermittent sound generation and its control in a free-shear flow

    NASA Astrophysics Data System (ADS)

    Cavalieri, André V. G.; Jordan, Peter; Gervais, Yves; Wei, Mingjun; Freund, Jonathan B.

    2010-11-01

    Comparisons are made between direct numerical simulations (DNS) of uncontrolled and optimally noise-controlled two-dimensional mixing layers in order to identify the physical mechanism responsible for the noise reduction. The analysis is carried out in the time domain to identify events that are significant in sound generation and which are acted upon by the control. Results show that a triple vortex interaction in the uncontrolled mixing layer radiates high-amplitude pressure waves to the far acoustic field; the elimination of this triple merging accounts for 70% of the noise reduction accomplished by a body force control applied normal to the shear layer. The effect of this control is shown to comprise vertical acceleration of vortical structures; the acceleration, whose action on the structures is convected across the control volume, leads to changes in their relative convection velocities and a consequent regularization of their evolution, which prevents the triple merger. Analysis of a longer time series for the DNS of the uncontrolled mixing layer using a wavelet transform identifies several similar intermittent, noisy events. The sound production mechanism associated with such noisy events can be understood in terms of cancellation disruption in a noncompact source region, such as described by a retarded-potential formalism. This shows that acoustic analogies formulated from the perspective of quadrupole acoustic sources are, in principle, useful for the modeling of such events. However, this study also illustrates the extent to which time-averaged statistical analysis of sound producing flows can mask the most important source activity, suggesting that intermittency should be explicitly modeled in sound prediction methodologies.

  14. Activation of auditory cortex by anticipating and hearing emotional sounds: an MEG study.

    PubMed

    Yokosawa, Koichi; Pamilo, Siina; Hirvenkari, Lotta; Hari, Riitta; Pihko, Elina

    2013-01-01

    To study how auditory cortical processing is affected by anticipating and hearing of long emotional sounds, we recorded auditory evoked magnetic fields with a whole-scalp MEG device from 15 healthy adults who were listening to emotional or neutral sounds. Pleasant, unpleasant, or neutral sounds, each lasting for 6 s, were played in a random order, preceded by 100-ms cue tones (0.5, 1, or 2 kHz) 2 s before the onset of the sound. The cue tones, indicating the valence of the upcoming emotional sounds, evoked typical transient N100m responses in the auditory cortex. During the rest of the anticipation period (until the beginning of the emotional sound), auditory cortices of both hemispheres generated slow shifts of the same polarity as N100m. During anticipation, the relative strengths of the auditory-cortex signals depended on the upcoming sound: towards the end of the anticipation period the activity became stronger when the subject was anticipating emotional rather than neutral sounds. During the actual emotional and neutral sounds, sustained fields were predominant in the left hemisphere for all sounds. The measured DC MEG signals during both anticipation and hearing of emotional sounds implied that following the cue that indicates the valence of the upcoming sound, the auditory-cortex activity is modulated by the upcoming sound category during the anticipation period.

  15. Might as well jump: sound affects muscle activation in skateboarding.

    PubMed

    Cesari, Paola; Camponogara, Ivan; Papetti, Stefano; Rocchesso, Davide; Fontana, Federico

    2014-01-01

    The aim of the study is to reveal the role of sound in action anticipation and performance, and to test whether the level of precision in action planning and execution is related to the level of sensorimotor skills and experience that listeners possess about a specific action. Individuals ranging from 18 to 75 years of age--some of them without any skills in skateboarding and others experts in this sport--were compared in their ability to anticipate and simulate a skateboarding jump by listening to the sound it produces. Only skaters were able to modulate the forces underfoot and to apply muscle synergies that closely resembled the ones that a skater would use if actually jumping on a skateboard. More importantly we showed that only skaters were able to plan the action by activating anticipatory postural adjustments about 200 ms after the jump event. We conclude that expert patterns are guided by auditory events that trigger proper anticipations of the corresponding patterns of movements.

  16. Might as Well Jump: Sound Affects Muscle Activation in Skateboarding

    PubMed Central

    Cesari, Paola; Camponogara, Ivan; Papetti, Stefano; Rocchesso, Davide; Fontana, Federico

    2014-01-01

    The aim of the study is to reveal the role of sound in action anticipation and performance, and to test whether the level of precision in action planning and execution is related to the level of sensorimotor skills and experience that listeners possess about a specific action. Individuals ranging from 18 to 75 years of age - some of them without any skills in skateboarding and others experts in this sport - were compared in their ability to anticipate and simulate a skateboarding jump by listening to the sound it produces. Only skaters were able to modulate the forces underfoot and to apply muscle synergies that closely resembled the ones that a skater would use if actually jumping on a skateboard. More importantly we showed that only skaters were able to plan the action by activating anticipatory postural adjustments about 200 ms after the jump event. We conclude that expert patterns are guided by auditory events that trigger proper anticipations of the corresponding patterns of movements. PMID:24619134

  17. Might as well jump: sound affects muscle activation in skateboarding.

    PubMed

    Cesari, Paola; Camponogara, Ivan; Papetti, Stefano; Rocchesso, Davide; Fontana, Federico

    2014-01-01

    The aim of the study is to reveal the role of sound in action anticipation and performance, and to test whether the level of precision in action planning and execution is related to the level of sensorimotor skills and experience that listeners possess about a specific action. Individuals ranging from 18 to 75 years of age--some of them without any skills in skateboarding and others experts in this sport--were compared in their ability to anticipate and simulate a skateboarding jump by listening to the sound it produces. Only skaters were able to modulate the forces underfoot and to apply muscle synergies that closely resembled the ones that a skater would use if actually jumping on a skateboard. More importantly we showed that only skaters were able to plan the action by activating anticipatory postural adjustments about 200 ms after the jump event. We conclude that expert patterns are guided by auditory events that trigger proper anticipations of the corresponding patterns of movements. PMID:24619134

  18. Activities report of the Institute of Sound and Vibration Research

    NASA Astrophysics Data System (ADS)

    Research concerning fluid dynamics and acoustics; audiology and human effects; structures and machinery; and signal processing and control is summarized. Aircraft noise; underwater acoustics; silencers; biomechanics; noise measurement; hearing; structural dynamics; laser technology; automotive engineering; and active control are discussed.

  19. Analyzing Activities in the Course of Science Education, According to Activity Theory: The Case of Sound

    ERIC Educational Resources Information Center

    Theodoraki, Xarikleia; Plakitsi, Katerina

    2013-01-01

    In the present study, we analyze activities on the topic of sound, which are performed in the science education laboratory lessons in the third-year students of the Department of Early Childhood Education at the University of Ioannina. The analysis of the activities is based on one of the most modern learning theories of CHAT (Cultural Historical…

  20. Application of subharmonics for active sound design of electric vehicles.

    PubMed

    Gwak, Doo Young; Yoon, Kiseop; Seong, Yeolwan; Lee, Soogab

    2014-12-01

    The powertrain of electric vehicles generates an unfamiliar acoustical environment for customers. This paper seeks optimal interior sound for electric vehicles based on psychoacoustic knowledge and musical harmonic theory. The concept of inserting a virtual sound, which consists of the subharmonics of an existing high-frequency component, is suggested to improve sound quality. Subjective evaluation results indicate that the impression of interior sound can be enhanced in this manner. Increased appeal is achieved through two designed stimuli, which proves the effectiveness of the method proposed.

  1. Application of subharmonics for active sound design of electric vehicles.

    PubMed

    Gwak, Doo Young; Yoon, Kiseop; Seong, Yeolwan; Lee, Soogab

    2014-12-01

    The powertrain of electric vehicles generates an unfamiliar acoustical environment for customers. This paper seeks optimal interior sound for electric vehicles based on psychoacoustic knowledge and musical harmonic theory. The concept of inserting a virtual sound, which consists of the subharmonics of an existing high-frequency component, is suggested to improve sound quality. Subjective evaluation results indicate that the impression of interior sound can be enhanced in this manner. Increased appeal is achieved through two designed stimuli, which proves the effectiveness of the method proposed. PMID:25480088

  2. Recent advances in active noise control

    NASA Astrophysics Data System (ADS)

    Guicking, D.

    Advances in the field of active noise control over the last few years are reviewed. Some commercially available products and their technical applications are described, with particular attention given to broadband duct noise silencers, broadband active headphones, waveform synthesis, and LMS controllers. Recent theoretical and experimental research activities are then reviewed. These activities are concerned with duct noise, structural sound, interior spaces, algorithms, echo cancellation, and miscellaneous applications.

  3. Experiments on structural control of sound transmitted through an elastic plate

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.; Silcox, R. J.; Metcalf, V. L.; Brown, D. E.

    1989-01-01

    Active control of sound transmission through an elastic plate has been experimentally studied. The control was applied directly to the plate by point force vibration inputs, and the error information and performance was measured in the radiated acoustic field by discrete microphones. Test cases were studied in which the error sensors were accelerometers mounted on the plate. A time-domain least-mean-squares adaptive algorithm was used as the basis of the control system design. The results showed an impressive increase in plate transmission loss over a wide range of frequencies with a maximum of two control shakers. The advantages of using error information derived from the radiated acoustic field rather than structural response is demonstrated. The mechanisms behind the efficiency of this control approach are discussed.

  4. Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

    PubMed

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance control reveals formal analogies with shunt strategies, and highlights an original method for synthesizing electric networks ("shunts") with positive or negative components, bridging the gap between passive and active acoustic impedance control. This paper describes the theory unifying all these passive and active acoustic impedance control strategies, introducing the concept of electroacoustic absorbers. The equivalence between shunts and active control is first formalized through the introduction of a one-degree-of-freedom acoustic resonator accounting for both electric shunts and acoustic feedbacks. Conversely, electric networks mimicking the performances of active feedback techniques are introduced, identifying shunts with active impedance control. Simulated acoustic performances are presented, with an emphasis on formal analogies between the different control techniques. Examples of electric shunts are proposed for active sound absorption. Experimental assessments are then presented, and the paper concludes with a general discussion on the concept and potential improvements.

  5. Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

    PubMed

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance control reveals formal analogies with shunt strategies, and highlights an original method for synthesizing electric networks ("shunts") with positive or negative components, bridging the gap between passive and active acoustic impedance control. This paper describes the theory unifying all these passive and active acoustic impedance control strategies, introducing the concept of electroacoustic absorbers. The equivalence between shunts and active control is first formalized through the introduction of a one-degree-of-freedom acoustic resonator accounting for both electric shunts and acoustic feedbacks. Conversely, electric networks mimicking the performances of active feedback techniques are introduced, identifying shunts with active impedance control. Simulated acoustic performances are presented, with an emphasis on formal analogies between the different control techniques. Examples of electric shunts are proposed for active sound absorption. Experimental assessments are then presented, and the paper concludes with a general discussion on the concept and potential improvements. PMID:21568400

  6. [ACTIVE AND PASSIVE DISCRIMINATION OF MOVING SOUNDS: RHYTHMIC ACTIVITY OF HUMAN BRAIN].

    PubMed

    Shestopalova, L B; Petropavlovskaia, E A; Nikitin, N I; Vaitulevich, S Ph

    2015-12-01

    The spectral dynamics of the EEG rhythmicity during active and passive discrimination of stationary and moving sound stimuli presented according to the oddball paradigm were investigated. Standard stimuli represented stationary midline sounds. Deviant stimuli simulated smooth and stepwise sound source motion (to the left/right from head midline) produced by linear and stepwise changes of interaural time delay. Significant changes of the brain oscillations were found in the frequency range of 3-30 Hz. The dynamics of the moving deviant stimuli (smooth vs. stepwise) had greater impact on theta-rhythm power in active listening conditions: a stronger theta-power increase was evoked by the stepwise sound motion as compared to smooth motion. Significant increase in theta-power was also observed with rightward sound displacement as compared to leftward displacements. Active deviant discrimination reduced alpha-power (8-11 Hz) mostly during smooth deviant motion. The power increase of lower alpha-oscillations (12-15 Hz) was stronger with step- wise motion than with smooth motion of deviants. The interhemispheric asymmetry of beta-power decrease in active conditions (as compared to passive) was found in the whole beta-range. The sup- pression of beta-power was stronger at the right hemisphere than at the midline or left hemisphere and showed no dependence on spatial properties of the deviant stimuli. This asymmetry may be related to selective attention to task-relevant sounds and with preparation to motor response. Generally, active auditory discrimination resulted in stronger deviant-related changes of the wide-ranged EEG spectral power than passive discrimination with attentional tuning to task-irrelevant stimuli.

  7. Activities report of the Institute of Sound and Vibration Research

    NASA Astrophysics Data System (ADS)

    Research in fluid dynamics and acoustics (noise and vibration control); audiology and human effects (audiotory communication and hearing conservation); structures and machinery (automotive design); and shock analysis is summarized. Underwater acoustics; active noise control; aircraft noise; wind turbine noise; laminar flow fans; helmet design; and the acoustics of flow ducts were studied.

  8. Common Sole Larvae Survive High Levels of Pile-Driving Sound in Controlled Exposure Experiments

    PubMed Central

    Bolle, Loes J.; de Jong, Christ A. F.; Bierman, Stijn M.; van Beek, Pieter J. G.; van Keeken, Olvin A.; Wessels, Peter W.; van Damme, Cindy J. G.; Winter, Hendrik V.; de Haan, Dick; Dekeling, René P. A.

    2012-01-01

    In view of the rapid extension of offshore wind farms, there is an urgent need to improve our knowledge on possible adverse effects of underwater sound generated by pile-driving. Mortality and injuries have been observed in fish exposed to loud impulse sounds, but knowledge on the sound levels at which (sub-)lethal effects occur is limited for juvenile and adult fish, and virtually non-existent for fish eggs and larvae. A device was developed in which fish larvae can be exposed to underwater sound. It consists of a rigid-walled cylindrical chamber driven by an electro-dynamical sound projector. Samples of up to 100 larvae can be exposed simultaneously to a homogeneously distributed sound pressure and particle velocity field. Recorded pile-driving sounds could be reproduced accurately in the frequency range between 50 and 1000 Hz, at zero to peak pressure levels up to 210 dB re 1µPa2 (zero to peak pressures up to 32 kPa) and single pulse sound exposure levels up to 186 dB re 1µPa2s. The device was used to examine lethal effects of sound exposure in common sole (Solea solea) larvae. Different developmental stages were exposed to various levels and durations of pile-driving sound. The highest cumulative sound exposure level applied was 206 dB re 1µPa2s, which corresponds to 100 strikes at a distance of 100 m from a typical North Sea pile-driving site. The results showed no statistically significant differences in mortality between exposure and control groups at sound exposure levels which were well above the US interim criteria for non-auditory tissue damage in fish. Although our findings cannot be extrapolated to fish larvae in general, as interspecific differences in vulnerability to sound exposure may occur, they do indicate that previous assumptions and criteria may need to be revised. PMID:22431996

  9. 75 FR 61857 - Statement on Sound Practices Concerning Elevated Risk Complex Structured Finance Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-06

    ... Office of Thrift Supervision Statement on Sound Practices Concerning Elevated Risk Complex Structured... Elevated Risk Complex Structured Finance Activities. OMB Number: 1550-0111. Form Number: N/A. Description: Statement on Sound Practices Concerning Elevated Risk Complex Structured Finance Activities describes...

  10. Speed of sound estimation with active PZT element for thermal monitoring during ablation therapy: feasibility study

    NASA Astrophysics Data System (ADS)

    Kim, Younsu; Guo, Xiaoyu; Cheng, Alexis; Boctor, Emad M.

    2016-04-01

    Controlling the thermal dose during ablation therapy is instrumental to successfully removing the tumor while preserving the surrounding healthy tissue. In the practical scenario, surgeons must be able to determine the ablation completeness in the tumor region. Various methods have been proposed to monitor it, one of which uses ultrasound since it is a common intraoperative imaging modality due to its non-invasive, cost-effective, and convenient natures. In our approach, we propose to use time of flight (ToF) information to estimate speed of sound changes. Accurate speed of sound estimation is crucial because it is directly correlated with temperature change and subsequent determination of ablation completeness. We divide the region of interest in a circular fashion with a variable radius from the ablator tip. We introduce the concept of effective speed of sound in each of the sub-regions. Our active PZT element control system facilitates this unique approach by allowing us to acquire one-way ToF information between the PZT element and each of the ultrasound elements. We performed a simulation and an experiment to verify feasibility of this method. The simulation result showed that we could compute the effective speed of sound within 0.02m/s error in our discrete model. We also perform a sensitivity analysis for this model. Most of the experimental results had less than 1% error. Simulation using a Gaussian continuous model with multiple PZT elements is also demonstrated. We simulate the effect of the element location one the optimization result.

  11. Active Control by Conservation of Energy Concept

    NASA Technical Reports Server (NTRS)

    Maestrello, Lucio

    2000-01-01

    Three unrelated experiments are discussed; each was extremely sensitive to initial conditions. The initial conditions are the beginnings of the origins of the information that nonlinearity displays. Initial conditions make the phenomenon unstable and unpredictable. With the knowledge of the initial conditions, active control requires far less power than that present in the system response. The first experiment is on the control of shocks from an axisymmetric supersonic jet; the second, control of a nonlinear panel response forced by turbulent boundary layer and sound; the third, control of subharmonic and harmonics of a panel forced by sound. In all three experiments, control is achieved by redistribution of periodic energy response such that the energy is nearly preserved from a previous uncontrolled state. This type of active control improves the performance of the system being controlled.

  12. Sound Perception: Rhythmic Brain Activity Really Is Important for Auditory Segregation.

    PubMed

    Snyder, Joel S

    2015-12-21

    A new study suggests that rhythmic brain activity plays a causal role in the perceptual segregation of sound patterns, rather than such activity simply being a non-functional by-product of sensory processing.

  13. Relations among pure-tone sound stimuli, neural activity, and the loudness sensation

    NASA Technical Reports Server (NTRS)

    Howes, W. L.

    1972-01-01

    Both the physiological and psychological responses to pure-tone sound stimuli are used to derive formulas which: (1) relate the loudness, loudness level, and sound-pressure level of pure tones; (2) apply continuously over most of the acoustic regime, including the loudness threshold; and (3) contain no undetermined coefficients. Some of the formulas are fundamental for calculating the loudness of any sound. Power-law formulas relating the pure-tone sound stimulus, neural activity, and loudness are derived from published data.

  14. TOGA COARE Upper-Air Sounding Data Archive: Development and Quality Control Procedures.

    NASA Astrophysics Data System (ADS)

    Loehrer, Scot M.; Edmands, Todd A.; Moore, James A.

    1996-11-01

    One of the most important datasets to wine from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) is the most complete, high-resolution upper-air sounding dataset ever collected in the equatorial western Pacific Ocean. The University Corporation for Atmospheric Research/Office of Field Project Support UCAR/OFPS (recently combined with the UCAR/Joint International Climate Projects Planning Office and renamed the Joint Office for Science Support)' was given the responsibility of processing, quality controlling, and archiving the dataset. OFPS, in consultation with the TOGA COARE scientific community, developed a four-stage process to provide the community with a thoroughly quality controlled dataset.The TOGA COARE sounding dataset includes over 14 000 soundings, collected from 14 countries, in over 20 different original formats. The first OFPS processing step was the conversion of all soundings to a single, easy to use format, the OFPS quality control format. The second stage was a series of automated internal consistency cheeks on each sounding. This stage was particularly important as it directly led to the improvement of several of the datasets. The third step was a visual examination of each sounding to provide another layer of internal consistency cheeks, for dewpoint and wind in particular. The final process used spatial quality control checks to put each station into context with its neighboring stations as well as the network as a whole. These cheeks provided statistics from which both systematic and individual sounding problems could be determined. Finally, some derived sounding parameters such as convective available potential energy (CAPE) were calculated for each sounding. The CAPE calculations provided a quick method to qualitatively examine the high-resolution sounding data for low-level humidity problems. A composite dataset of all soundings at a uniform vertical resolution of 5 hPa was created to provide

  15. Superior Analgesic Effect of an Active Distraction versus Pleasant Unfamiliar Sounds and Music: The Influence of Emotion and Cognitive Style

    PubMed Central

    Garza Villarreal, Eduardo A.; Brattico, Elvira; Vase, Lene; Østergaard, Leif; Vuust, Peter

    2012-01-01

    Listening to music has been found to reduce acute and chronic pain. The underlying mechanisms are poorly understood; however, emotion and cognitive mechanisms have been suggested to influence the analgesic effect of music. In this study we investigated the influence of familiarity, emotional and cognitive features, and cognitive style on music-induced analgesia. Forty-eight healthy participants were divided into three groups (empathizers, systemizers and balanced) and received acute pain induced by heat while listening to different sounds. Participants listened to unfamiliar Mozart music rated with high valence and low arousal, unfamiliar environmental sounds with similar valence and arousal as the music, an active distraction task (mental arithmetic) and a control, and rated the pain. Data showed that the active distraction led to significantly less pain than did the music or sounds. Both unfamiliar music and sounds reduced pain significantly when compared to the control condition; however, music was no more effective than sound to reduce pain. Furthermore, we found correlations between pain and emotion ratings. Finally, systemizers reported less pain during the mental arithmetic compared with the other two groups. These findings suggest that familiarity may be key in the influence of the cognitive and emotional mechanisms of music-induced analgesia, and that cognitive styles may influence pain perception. PMID:22242169

  16. Superior analgesic effect of an active distraction versus pleasant unfamiliar sounds and music: the influence of emotion and cognitive style.

    PubMed

    Villarreal, Eduardo A Garza; Brattico, Elvira; Vase, Lene; Østergaard, Leif; Vuust, Peter

    2012-01-01

    Listening to music has been found to reduce acute and chronic pain. The underlying mechanisms are poorly understood; however, emotion and cognitive mechanisms have been suggested to influence the analgesic effect of music. In this study we investigated the influence of familiarity, emotional and cognitive features, and cognitive style on music-induced analgesia. Forty-eight healthy participants were divided into three groups (empathizers, systemizers and balanced) and received acute pain induced by heat while listening to different sounds. Participants listened to unfamiliar Mozart music rated with high valence and low arousal, unfamiliar environmental sounds with similar valence and arousal as the music, an active distraction task (mental arithmetic) and a control, and rated the pain. Data showed that the active distraction led to significantly less pain than did the music or sounds. Both unfamiliar music and sounds reduced pain significantly when compared to the control condition; however, music was no more effective than sound to reduce pain. Furthermore, we found correlations between pain and emotion ratings. Finally, systemizers reported less pain during the mental arithmetic compared with the other two groups. These findings suggest that familiarity may be key in the influence of the cognitive and emotional mechanisms of music-induced analgesia, and that cognitive styles may influence pain perception.

  17. Different categories of living and non-living sound-sources activate distinct cortical networks

    PubMed Central

    Engel, Lauren R.; Frum, Chris; Puce, Aina; Walker, Nathan A.; Lewis, James W.

    2009-01-01

    With regard to hearing perception, it remains unclear as to whether, or the extent to which, different conceptual categories of real-world sounds and related categorical knowledge are differentially represented in the brain. Semantic knowledge representations are reported to include the major divisions of living versus non-living things, plus more specific categories including animals, tools, biological motion, faces, and places—categories typically defined by their characteristic visual features. Here, we used functional magnetic resonance imaging (fMRI) to identify brain regions showing preferential activity to four categories of action sounds, which included non-vocal human and animal actions (living), plus mechanical and environmental sound-producing actions (non-living). The results showed a striking antero-posterior division in cortical representations for sounds produced by living versus non-living sources. Additionally, there were several significant differences by category, depending on whether the task was category-specific (e.g. human or not) versus non-specific (detect end-of-sound). In general, (1) human-produced sounds yielded robust activation in the bilateral posterior superior temporal sulci independent of task. Task demands modulated activation of left-lateralized fronto-parietal regions, bilateral insular cortices, and subcortical regions previously implicated in observation-execution matching, consistent with “embodied” and mirror-neuron network representations subserving recognition. (2) Animal action sounds preferentially activated the bilateral posterior insulae. (3) Mechanical sounds activated the anterior superior temporal gyri and parahippocampal cortices. (4) Environmental sounds preferentially activated dorsal occipital and medial parietal cortices. Overall, this multi-level dissociation of networks for preferentially representing distinct sound-source categories provides novel support for grounded cognition models that may

  18. Motor control of sound frequency in birdsong involves the interaction between air sac pressure and labial tension

    NASA Astrophysics Data System (ADS)

    Alonso, Rodrigo; Goller, Franz; Mindlin, Gabriel B.

    2014-03-01

    Frequency modulation is a salient acoustic feature of birdsong. Its control is usually attributed to the activity of syringeal muscles, which affect the tension of the labia responsible for sound production. We use experimental and theoretical tools to test the hypothesis that for birds producing tonal sounds such as domestic canaries (Serinus canaria), frequency modulation is determined by both the syringeal tension and the air sac pressure. For different models, we describe the structure of the isofrequency curves, which are sets of parameters leading to sounds presenting the same fundamental frequencies. We show how their shapes determine the relative roles of syringeal tension and air sac pressure in frequency modulation. Finally, we report experiments that allow us to unveil the features of the isofrequency curves.

  19. Cortical Activation during Attention to Sound in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Funabiki, Yasuko; Murai, Toshiya; Toichi, Motomi

    2012-01-01

    Individuals with autism spectrum disorders (ASDs) can demonstrate hypersensitivity to sounds as well as a lack of awareness of them. Several functional imaging studies have suggested an abnormal response in the auditory cortex of such subjects, but it is not known whether these subjects have dysfunction in the auditory cortex or are simply not…

  20. Activities of the Institute of Sound and Vibration Research

    NASA Astrophysics Data System (ADS)

    Research in fluid dynamics, acoustics, automotive engineering, audiology, noise and vibration effects (on human beings), and structural response to noise and vibration was carried out. Aircraft noise, acoustics of flow duct systems and enclosures, acoustic modeling, sound propagation, and acoustic measurement techniques were studied. Auditory and vestibular functions and electrophysiology were investigated.

  1. Noise control, sound, and the vehicle design process

    NASA Astrophysics Data System (ADS)

    Donavan, Paul

    2005-09-01

    For many products, noise and sound are viewed as necessary evils that need to be dealt with in order to bring the product successfully to market. They are generally not product ``exciters'' although some vehicle manufacturers do tune and advertise specific sounds to enhance the perception of their products. In this paper, influencing the design process for the ``evils,'' such as wind noise and road noise, are considered in more detail. There are three ingredients to successfully dealing with the evils in the design process. The first of these is knowing how excesses in noise effects the end customer in a tangible manner and how that effects customer satisfaction and ultimately sells. The second is having and delivering the knowledge of what is required of the design to achieve a satisfactory or even better level of noise performance. The third ingredient is having the commitment of the designers to incorporate the knowledge into their part, subsystem or system. In this paper, the elements of each of these ingredients are discussed in some detail and the attributes of a successful design process are enumerated.

  2. Low frequency sound as a control measure for zebra mussel fouling

    SciTech Connect

    Donskoy, D.M.; Ludyanskiy, M.L.

    1995-06-01

    The study of the effect of acoustic energy on zebra mussels first began in the Soviet Union over 30 years ago, where researchers indicated the feasibility of reducing Dreissena fouling, in particular on cooling systems. However, these studies were discontinued due to the successful use of chlorination and the relatively low level of technology at that time in the Soviet Union. Interest in the use of acoustic energy as a control measure has been revived, and the three major approaches are: (1) cavitation, (2) sound treatment, and (3) sound treatment. The objective of the present paper is to determine the feasibility and effectivensss of low frequency sound techniques to fight zebra mussel fouling. A number of experiments were performed, and the results are presented and discussed. It is concluded that low frequency sound can be an effective means of control of zebra mussel fouling.

  3. Prey-mediated behavioral responses of feeding blue whales in controlled sound exposure experiments.

    PubMed

    Friedlaender, A S; Hazen, E L; Goldbogen, J A; Stimpert, A K; Calambokidis, J; Southall, B L

    2016-06-01

    Behavioral response studies provide significant insights into the nature, magnitude, and consequences of changes in animal behavior in response to some external stimulus. Controlled exposure experiments (CEEs) to study behavioral response have faced challenges in quantifying the importance of and interaction among individual variability, exposure conditions, and environmental covariates. To investigate these complex parameters relative to blue whale behavior and how it may change as a function of certain sounds, we deployed multi-sensor acoustic tags and conducted CEEs using simulated mid-frequency active sonar (MFAS) and pseudo-random noise (PRN) stimuli, while collecting synoptic, quantitative prey measures. In contrast to previous approaches that lacked such prey data, our integrated approach explained substantially more variance in blue whale dive behavioral responses to mid-frequency sounds (r2 = 0.725 vs. 0.14 previously). Results demonstrate that deep-feeding whales respond more clearly and strongly to CEEs than those in other behavioral states, but this was only evident with the increased explanatory power provided by incorporating prey density and distribution as contextual covariates. Including contextual variables increases the ability to characterize behavioral variability and empirically strengthens previous findings that deep-feeding blue whales respond significantly to mid-frequency sound exposure. However, our results are only based on a single behavioral state with a limited sample size, and this analytical framework should be applied broadly across behavioral states. The increased capability to describe and account for individual response variability by including environmental variables, such as prey, that drive foraging behavior underscores the importance of integrating these and other relevant contextual parameters in experimental designs. Our results suggest the need to measure and account for the ecological dynamics of predator

  4. Prey-mediated behavioral responses of feeding blue whales in controlled sound exposure experiments.

    PubMed

    Friedlaender, A S; Hazen, E L; Goldbogen, J A; Stimpert, A K; Calambokidis, J; Southall, B L

    2016-06-01

    Behavioral response studies provide significant insights into the nature, magnitude, and consequences of changes in animal behavior in response to some external stimulus. Controlled exposure experiments (CEEs) to study behavioral response have faced challenges in quantifying the importance of and interaction among individual variability, exposure conditions, and environmental covariates. To investigate these complex parameters relative to blue whale behavior and how it may change as a function of certain sounds, we deployed multi-sensor acoustic tags and conducted CEEs using simulated mid-frequency active sonar (MFAS) and pseudo-random noise (PRN) stimuli, while collecting synoptic, quantitative prey measures. In contrast to previous approaches that lacked such prey data, our integrated approach explained substantially more variance in blue whale dive behavioral responses to mid-frequency sounds (r2 = 0.725 vs. 0.14 previously). Results demonstrate that deep-feeding whales respond more clearly and strongly to CEEs than those in other behavioral states, but this was only evident with the increased explanatory power provided by incorporating prey density and distribution as contextual covariates. Including contextual variables increases the ability to characterize behavioral variability and empirically strengthens previous findings that deep-feeding blue whales respond significantly to mid-frequency sound exposure. However, our results are only based on a single behavioral state with a limited sample size, and this analytical framework should be applied broadly across behavioral states. The increased capability to describe and account for individual response variability by including environmental variables, such as prey, that drive foraging behavior underscores the importance of integrating these and other relevant contextual parameters in experimental designs. Our results suggest the need to measure and account for the ecological dynamics of predator

  5. A Organization for High-Level Interactive Programmatic Control of Computer-Generated Sound.

    NASA Astrophysics Data System (ADS)

    Das, Sumit

    The state of computer generated sound has advanced rapidly, and there exist many different ways of conceptualizing the abstract sound structures that comprise music and other complex organizations of sound. Many of these methods are radically different from one another, and so are not usually used within the same system. One problem that almost all methods share is one of control, as large amounts of data are needed to specify sounds. How do we create, examine, and modify these complex structures? The problem is exacerbated if we consider the realm of interactively controlled sound. This paper presents an organization which, rather than forcing a particular way of thinking about sound, allows multiple arbitrarily high-level views to coexist, all sharing a common interface. The methods or algorithms are abstracted into objects called auditory actors. This encapsulation allows different algorithms to be used concurrently. All communication with and between these actors is carried out through message-passing, which allows arbitrary types of information (such as other messages) to be easily communicated. This standardizes control without limiting it to a particular type of data. A prototype system was implemented using this model. This system was used by a number of different developers to create audio interfaces for interactive virtual reality applications, which were demonstrated at the SIGGRAPH 94 conference in Orlando, Florida. Compared to earlier systems, developers were able to create more complex audio interfaces in a shorter time.

  6. Velocity controlled sound field reproduction by non-uniformly spaced loudspeakers

    NASA Astrophysics Data System (ADS)

    Shin, Mincheol; Nelson, Philip A.; Fazi, Filippo M.; Seo, Jeongil

    2016-05-01

    One approach to the reproduction of a sound field is to ensure the reproduction of the acoustic pressure on the surface bounding the volume within which reproduction is sought. However, this approach suffers from technical limitations when the loudspeakers used for the reproduction of the surface acoustic pressures are unevenly spaced. It is shown in this paper that sound field reproduction with a spatially non-uniform loudspeaker arrangement can be considerably improved by changing the physical quantity to be controlled on the bounding surface from pressure to particle velocity. One of the main advantages of the velocity control method is the simplicity with which the inverse problem can be regularized, irrespective of the direction of arrival of the sound to be reproduced. In addition, the velocity controlled sound field shows better reproduction of the time averaged intensity flow in the reproduction region which in turn appears to be closely linked with better human perception of sound localization. Furthermore, the proposed method results in smoother "panning functions" that describe the variation of the source outputs as a function of the angle of incidence of the sound to be reproduced. The performance of the velocity matching method has been evaluated by comparison to the conventional pressure matching method and through simulations with several non-uniform loudspeaker layouts. The simulated results were also verified with experiments and subjective tests.

  7. Modeled Aeromagnetic Anomalies, Controlled By Radar Ice Sounding, As Evidence for Subglacial Volcanic Activity in the West Antarctic Rift System (WR) Beneath the Area of the Divide of the West Antarctic Ice Sheet (WAIS)

    NASA Astrophysics Data System (ADS)

    Behrendt, J. C.

    2014-12-01

    The Thwaites and Pine Island ice shelves, buttressing the WAIS, have passed the turning point as they are eaten away by warmer ocean waters (Joghin et al., 2014; Rignot et al., 2014). There is an increasing evidence (aeromagnetic, radar ice-sounding, high heat flow, subglacial volcanic seismicity, and several exposed and subglacial active volcanoes), for volcanic activity in the WR beneath the WAIS, which flows through it. The 5-km, orthogonally line spaced, central West Antarctica (CWA) aerogeophysical survey defined >400 high amplitude volcanic magnetic anomalies correlated with glacial bed topography. Modeled anomalies defined magnetic properties; interpreted volcanic edifices were mostly removed by the moving ice into which they were erupted. Very high apparent susceptibility contrasts (.001->.3 SI) are typical of measured properties from volcanic exposures in the WAIS area. About 90% of the magnetic sources have normal magnetization in the present field direction. Two explanations as to why the anomalies are not approximately 50% negative: (1) Volcanic activity resulting in these anomalies occurred in a predominantly normal field (unlikely). (2) Sources are a combination of induced and remanent magnetization resulting in anomalies of low amplitude (induced cancels remanent) and are not recognized because they are <100 nT (most probable). About 18 high relief, (~600-2000 m) "volcanic centers" beneath the WAIS surface, probably were erupted subaerially when the WAIS was absent; nine of these are in the general area beneath the divide of the WAIS. A 70-km wide, ring of interpreted subglacial volcanic rocks may define a volcanic caldera underlying thedivide (Behrendt et al., 1998). A 2 km-high subaerially erupted volcano (subglacial Mt Thiel, ~78o30'S, 111oW) ~ 100 km north of the WAISCORE, could be the source an ash layer observed in the core. Models by Tulaczyk and Hossainzadeh (2011) indicate >4mm/yr basal melting beneath the WAIS, supportive of high heat flow

  8. Auditory Attraction: Activation of visual cortex by music and sound in Williams syndrome

    PubMed Central

    Thornton-Wells, Tricia A.; Cannistraci, Chris J.; Anderson, Adam; Kim, Chai-Youn; Eapen, Mariam; Gore, John C.; Blake, Randolph; Dykens, Elisabeth M.

    2009-01-01

    Williams syndrome (WS) is a genetic neurodevelopmental disorder with a distinctive phenotype including cognitive-linguistic features, non-social anxiety, and a strong attraction to music. We performed functional MRI studies examining brain responses to musical and other types of auditory stimuli in young adults with WS and typically-developing controls. In Study 1, the WS group exhibited unforeseen activations of the visual cortex to musical stimuli, and it was this novel finding that became the focus of two subsequent studies. Using retinotopy, color localizers and additional sound conditions, we identified specific visual areas in WS subjects that were activated by both musical and non-musical auditory stimuli. The results, similar to synesthetic-like experiences, have implications for cross-modal sensory processing in typical and atypical neurodevelopment. PMID:20440382

  9. A functional neuroimaging study of sound localization: visual cortex activity predicts performance in early-blind individuals.

    PubMed

    Gougoux, Frédéric; Zatorre, Robert J; Lassonde, Maryse; Voss, Patrice; Lepore, Franco

    2005-02-01

    Blind individuals often demonstrate enhanced nonvisual perceptual abilities. However, the neural substrate that underlies this improved performance remains to be fully understood. An earlier behavioral study demonstrated that some early-blind people localize sounds more accurately than sighted controls using monaural cues. In order to investigate the neural basis of these behavioral differences in humans, we carried out functional imaging studies using positron emission tomography and a speaker array that permitted pseudo-free-field presentations within the scanner. During binaural sound localization, a sighted control group showed decreased cerebral blood flow in the occipital lobe, which was not seen in early-blind individuals. During monaural sound localization (one ear plugged), the subgroup of early-blind subjects who were behaviorally superior at sound localization displayed two activation foci in the occipital cortex. This effect was not seen in blind persons who did not have superior monaural sound localization abilities, nor in sighted individuals. The degree of activation of one of these foci was strongly correlated with sound localization accuracy across the entire group of blind subjects. The results show that those blind persons who perform better than sighted persons recruit occipital areas to carry out auditory localization under monaural conditions. We therefore conclude that computations carried out in the occipital cortex specifically underlie the enhanced capacity to use monaural cues. Our findings shed light not only on intermodal compensatory mechanisms, but also on individual differences in these mechanisms and on inhibitory patterns that differ between sighted individuals and those deprived of vision early in life. PMID:15678166

  10. Sounds elicit relative left frontal alpha activity in 2-month-old infants

    PubMed Central

    Mai, Xiaoqin; Xu, Lin; Li, Mingyan; Shao, Jie; Zhao, Zhengyan; Lamm, Connie; Fox, Nathan A.; Nelson, Charles A.; Lozoff, Betsy

    2015-01-01

    As one kind of sounds, human voices are important for language acquisition and human-infant relations. Human voices have positive effects on infants, e.g., soothe infants and evoke an infant's smile. Increased left relative to right frontal alpha activity as assessed by the electroencephalogram (EEG) is considered to reflect approach-related emotions. In the present study, we recorded the EEG in thirty-eight 2-month-old infants during a baseline period and then while they listened to sounds, i.e., human voices. Infants displayed increased relative left frontal alpha activity in response to sounds compared to the baseline condition. These results suggest that sounds can elicit relative left frontal activity in young infants, and that this approach-related emotion presents early in life. PMID:25242501

  11. Active noise control using a steerable parametric array loudspeaker.

    PubMed

    Tanaka, Nobuo; Tanaka, Motoki

    2010-06-01

    Arguably active noise control enables the sound suppression at the designated control points, while the sound pressure except the targeted locations is likely to augment. The reason is clear; a control source normally radiates the sound omnidirectionally. To cope with this problem, this paper introduces a parametric array loudspeaker (PAL) which produces a spatially focused sound beam due to the attribute of ultrasound used for carrier waves, thereby allowing one to suppress the sound pressure at the designated point without causing spillover in the whole sound field. First the fundamental characteristics of PAL are overviewed. The scattered pressure in the near field contributed by source strength of PAL is then described, which is needed for the design of an active noise control system. Furthermore, the optimal control law for minimizing the sound pressure at control points is derived, the control effect being investigated analytically and experimentally. With a view to tracking a moving target point, a steerable PAL based upon a phased array scheme is presented, with the result that the generation of a moving zone of quiet becomes possible without mechanically rotating the PAL. An experiment is finally conducted, demonstrating the validity of the proposed method.

  12. The auditory midbrain of people with tinnitus: abnormal sound-evoked activity revisited.

    PubMed

    Melcher, Jennifer R; Levine, Robert A; Bergevin, Christopher; Norris, Barbara

    2009-11-01

    Sound-evoked fMRI activation of the inferior colliculi (IC) was compared between tinnitus and non-tinnitus subjects matched in threshold (normal), age, depression, and anxiety. Subjects were stimulated with broadband sound in an "on/off" fMRI paradigm with and without on-going sound from the scanner coolant pump. (1) With pump sounds off, the tinnitus group showed greater stimulus-evoked activation of the IC than the non-tinnitus group, suggesting abnormal gain within the auditory pathway of tinnitus subjects. (2) Having pump sounds on reduced activation in the tinnitus, but not the non-tinnitus group. This result suggests response saturation in tinnitus subjects, possibly occurring because abnormal gain increased response amplitude to an upper limit. (3) In contrast to Melcher et al. (2000), the ratio of activation between right and left IC did not differ significantly between tinnitus and non-tinnitus subjects or in a manner dependent on tinnitus laterality. However, new data from subjects imaged previously by Melcher et al. suggest a possible tinnitus subgroup with abnormally asymmetric function of the IC. The present and previous data together suggest elevated responses to sound in the IC are common among those with tinnitus and normal thresholds, while abnormally asymmetric activation is not, even among those with lateralized tinnitus. PMID:19699287

  13. Developmental changes in brain activation involved in the production of novel speech sounds in children.

    PubMed

    Hashizume, Hiroshi; Taki, Yasuyuki; Sassa, Yuko; Thyreau, Benjamin; Asano, Michiko; Asano, Kohei; Takeuchi, Hikaru; Nouchi, Rui; Kotozaki, Yuka; Jeong, Hyeonjeong; Sugiura, Motoaki; Kawashima, Ryuta

    2014-08-01

    Older children are more successful at producing unfamiliar, non-native speech sounds than younger children during the initial stages of learning. To reveal the neuronal underpinning of the age-related increase in the accuracy of non-native speech production, we examined the developmental changes in activation involved in the production of novel speech sounds using functional magnetic resonance imaging. Healthy right-handed children (aged 6-18 years) were scanned while performing an overt repetition task and a perceptual task involving aurally presented non-native and native syllables. Productions of non-native speech sounds were recorded and evaluated by native speakers. The mouth regions in the bilateral primary sensorimotor areas were activated more significantly during the repetition task relative to the perceptual task. The hemodynamic response in the left inferior frontal gyrus pars opercularis (IFG pOp) specific to non-native speech sound production (defined by prior hypothesis) increased with age. Additionally, the accuracy of non-native speech sound production increased with age. These results provide the first evidence of developmental changes in the neural processes underlying the production of novel speech sounds. Our data further suggest that the recruitment of the left IFG pOp during the production of novel speech sounds was possibly enhanced due to the maturation of the neuronal circuits needed for speech motor planning. This, in turn, would lead to improvement in the ability to immediately imitate non-native speech.

  14. Digital servo control of random sound test excitation. [in reverberant acoustic chamber

    NASA Technical Reports Server (NTRS)

    Nakich, R. B. (Inventor)

    1974-01-01

    A digital servocontrol system for random noise excitation of a test object in a reverberant acoustic chamber employs a plurality of sensors spaced in the sound field to produce signals in separate channels which are decorrelated and averaged. The average signal is divided into a plurality of adjacent frequency bands cyclically sampled by a time division multiplex system, converted into digital form, and compared to a predetermined spectrum value stored in digital form. The results of the comparisons are used to control a time-shared up-down counter to develop gain control signals for the respective frequency bands in the spectrum of random sound energy picked up by the microphones.

  15. Low-frequency sound affects active micromechanics in the human inner ear

    PubMed Central

    Kugler, Kathrin; Wiegrebe, Lutz; Grothe, Benedikt; Kössl, Manfred; Gürkov, Robert; Krause, Eike; Drexl, Markus

    2014-01-01

    Noise-induced hearing loss is one of the most common auditory pathologies, resulting from overstimulation of the human cochlea, an exquisitely sensitive micromechanical device. At very low frequencies (less than 250 Hz), however, the sensitivity of human hearing, and therefore the perceived loudness is poor. The perceived loudness is mediated by the inner hair cells of the cochlea which are driven very inadequately at low frequencies. To assess the impact of low-frequency (LF) sound, we exploited a by-product of the active amplification of sound outer hair cells (OHCs) perform, so-called spontaneous otoacoustic emissions. These are faint sounds produced by the inner ear that can be used to detect changes of cochlear physiology. We show that a short exposure to perceptually unobtrusive, LF sounds significantly affects OHCs: a 90 s, 80 dB(A) LF sound induced slow, concordant and positively correlated frequency and level oscillations of spontaneous otoacoustic emissions that lasted for about 2 min after LF sound offset. LF sounds, contrary to their unobtrusive perception, strongly stimulate the human cochlea and affect amplification processes in the most sensitive and important frequency range of human hearing. PMID:26064536

  16. Effects of Active and Passive Hearing Protection Devices on Sound Source Localization, Speech Recognition, and Tone Detection

    PubMed Central

    Brown, Andrew D.; Beemer, Brianne T.; Greene, Nathaniel T.; Argo, Theodore; Meegan, G. Douglas; Tollin, Daniel J.

    2015-01-01

    Hearing protection devices (HPDs) such as earplugs offer to mitigate noise exposure and reduce the incidence of hearing loss among persons frequently exposed to intense sound. However, distortions of spatial acoustic information and reduced audibility of low-intensity sounds caused by many existing HPDs can make their use untenable in high-risk (e.g., military or law enforcement) environments where auditory situational awareness is imperative. Here we assessed (1) sound source localization accuracy using a head-turning paradigm, (2) speech-in-noise recognition using a modified version of the QuickSIN test, and (3) tone detection thresholds using a two-alternative forced-choice task. Subjects were 10 young normal-hearing males. Four different HPDs were tested (two active, two passive), including two new and previously untested devices. Relative to unoccluded (control) performance, all tested HPDs significantly degraded performance across tasks, although one active HPD slightly improved high-frequency tone detection thresholds and did not degrade speech recognition. Behavioral data were examined with respect to head-related transfer functions measured using a binaural manikin with and without tested HPDs in place. Data reinforce previous reports that HPDs significantly compromise a variety of auditory perceptual facilities, particularly sound localization due to distortions of high-frequency spectral cues that are important for the avoidance of front-back confusions. PMID:26313145

  17. Effects of Active and Passive Hearing Protection Devices on Sound Source Localization, Speech Recognition, and Tone Detection.

    PubMed

    Brown, Andrew D; Beemer, Brianne T; Greene, Nathaniel T; Argo, Theodore; Meegan, G Douglas; Tollin, Daniel J

    2015-01-01

    Hearing protection devices (HPDs) such as earplugs offer to mitigate noise exposure and reduce the incidence of hearing loss among persons frequently exposed to intense sound. However, distortions of spatial acoustic information and reduced audibility of low-intensity sounds caused by many existing HPDs can make their use untenable in high-risk (e.g., military or law enforcement) environments where auditory situational awareness is imperative. Here we assessed (1) sound source localization accuracy using a head-turning paradigm, (2) speech-in-noise recognition using a modified version of the QuickSIN test, and (3) tone detection thresholds using a two-alternative forced-choice task. Subjects were 10 young normal-hearing males. Four different HPDs were tested (two active, two passive), including two new and previously untested devices. Relative to unoccluded (control) performance, all tested HPDs significantly degraded performance across tasks, although one active HPD slightly improved high-frequency tone detection thresholds and did not degrade speech recognition. Behavioral data were examined with respect to head-related transfer functions measured using a binaural manikin with and without tested HPDs in place. Data reinforce previous reports that HPDs significantly compromise a variety of auditory perceptual facilities, particularly sound localization due to distortions of high-frequency spectral cues that are important for the avoidance of front-back confusions. PMID:26313145

  18. [Optimally control urban railway noise by sound propagation path].

    PubMed

    Di, Guo-qing; Li, Zheng-guang; Chen, Yu; Zhang, Bang-jun

    2008-08-01

    In order to control railway noise pollution in urban areas, the residential district located near the Zhegan railway in Hangzhou urban was taken for example, and some controlling measures were proposed based on the investigation in railway noise impact as well as the planning of the district, the environmental scene and the project devises. The measures included setting man-made soil slopes, noise barriers and virescence. Combining some of them could be a typical noise reduction scheme. The professional software Cadna/A was used to predict the noise reduction results of every scheme. Results show that the maximal difference of noise reduction is 19.4 dB and the noise reduction effect of the second scheme is best. However, if only railway noise influence is considered, the first scheme is best. The research results can provide reference for residential districts planning and noise control near the railway in urban areas.

  19. Effects of Natural Sounds on Pain: A Randomized Controlled Trial with Patients Receiving Mechanical Ventilation Support.

    PubMed

    Saadatmand, Vahid; Rejeh, Nahid; Heravi-Karimooi, Majideh; Tadrisi, Sayed Davood; Vaismoradi, Mojtaba; Jordan, Sue

    2015-08-01

    Nonpharmacologic pain management in patients receiving mechanical ventilation support in critical care units is under investigated. Natural sounds may help reduce the potentially harmful effects of anxiety and pain in hospitalized patients. The aim of this study was to examine the effect of pleasant, natural sounds on self-reported pain in patients receiving mechanical ventilation support, using a pragmatic parallel-arm, randomized controlled trial. The study was conducted in a general adult intensive care unit of a high-turnover teaching hospital, in Tehran, Iran. Between October 2011 and June 2012, we recruited 60 patients receiving mechanical ventilation support to the intervention (n = 30) and control arms (n = 30) of a pragmatic parallel-group, randomized controlled trial. Participants in both arms wore headphones for 90 minutes. Those in the intervention arm heard pleasant, natural sounds, whereas those in the control arm heard nothing. Outcome measures included the self-reported visual analog scale for pain at baseline; 30, 60, and 90 minutes into the intervention; and 30 minutes post-intervention. All patients approached agreed to participate. The trial arms were similar at baseline. Pain scores in the intervention arm fell and were significantly lower than in the control arm at each time point (p < .05). Administration of pleasant, natural sounds via headphones is a simple, safe, nonpharmacologic nursing intervention that may be used to allay pain for up to 120 minutes in patients receiving mechanical ventilation support.

  20. Locomotion of the blind controlled by natural sound cues.

    PubMed

    Strelow, E R; Brabyn, J A

    1982-01-01

    Measures of the accuracy of locomotion control were taken with blind and blindfolded sighted subjects using the natural auditory obstacle sense to locate a travel path. These measures were compared with the accuracy of visual guidance. While the blind show a greater skill than blindfolded sighted subjects in using auditory cues for guidance, auditory guidance is notably inferior to visual guidance and deteriorates markedly when smaller targets are used to define the travel path. The natural obstacle sense thus appears to give only a rudimentary perception of the presence of objects and does not provide sufficient spatial information to allow accurate locomotion control.

  1. Noise and Sound Control in Open Plan Schools.

    ERIC Educational Resources Information Center

    Schellenberg, Ben

    This annotated bibliography includes summaries of 19 articles and reports dealing with noise control and acoustical design in school buildings. A brief introduction discusses the need for careful attention to acoustics in any school construction or remodeling project, with particular emphasis on the need for special acoustical measures in an open…

  2. Sound-Induced Activity in Voice-Sensitive Cortex Predicts Voice Memory Ability

    PubMed Central

    Watson, Rebecca; Latinus, Marianne; Bestelmeyer, Patricia E. G.; Crabbe, Frances; Belin, Pascal

    2012-01-01

    The “temporal voice areas” (TVAs; Belin et al., 2000) of the human brain show greater neuronal activity in response to human voices than to other categories of non-vocal sounds. However, a direct link between TVA activity and voice perception behavior has not yet been established. Here we show that a functional magnetic resonance imaging measure of activity in the TVAs predicts individual performance at a separately administered voice memory test. This relation holds when general sound memory ability is taken into account. These findings provide the first evidence that the TVAs are specifically involved in voice cognition. PMID:22485101

  3. Active noise control using a distributed mode flat panel loudspeaker.

    PubMed

    Zhu, H; Rajamani, R; Dudney, J; Stelson, K A

    2003-07-01

    A flat panel distributed mode loudspeaker (DML) has many advantages over traditional cone speakers in terms of its weight, size, and durability. However, its frequency response is uneven and complex, thus bringing its suitability for active noise control (ANC) under question. This paper presents experimental results demonstrating the effective use of panel DML speakers in an ANC application. Both feedback and feedforward control techniques are considered. Effective feedback control with a flat panel speaker could open up a whole range of new noise control applications and has many advantages over feedforward control. The paper develops a new control algorithm to attenuate tonal noise of a known frequency by feedback control. However, due to the uneven response of the speakers, feedback control is found to be only moderately effective even for this narrow-band application. Feedforward control proves to be most capable for the flat panel speaker. Using feedforward control, the sound pressure level can be significantly reduced in close proximity to an error microphone. The paper demonstrates an interesting application of the flat panel in which the panel is placed in the path of sound and effectively used to block sound transmission using feedforward control. This is a new approach to active noise control enabled by the use of flat panels and can be used to prevent sound from entering into an enclosure in the first place rather than the traditional approach of attempting to cancel sound after it enters the enclosure.

  4. Decentralized Control of Sound Radiation from an Aircraft-Style Panel Using Iterative Loop Recovery

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Cabell, Randolph H.; Fuller, Chris R.

    2008-01-01

    A decentralized LQG-based control strategy is designed to reduce low-frequency sound transmission through periodically stiffened panels. While modern control strategies have been used to reduce sound radiation from relatively simple structural acoustic systems, significant implementation issues have to be addressed before these control strategies can be extended to large systems such as the fuselage of an aircraft. For instance, centralized approaches typically require a high level of connectivity and are computationally intensive, while decentralized strategies face stability problems caused by the unmodeled interaction between neighboring control units. Since accurate uncertainty bounds are not known a priori, it is difficult to ensure the decentralized control system will be robust without making the controller overly conservative. Therefore an iterative approach is suggested, which utilizes frequency-shaped loop recovery. The approach accounts for modeling error introduced by neighboring control loops, requires no communication between subsystems, and is relatively simple. The control strategy is validated using real-time control experiments performed on a built-up aluminum test structure representative of the fuselage of an aircraft. Experiments demonstrate that the iterative approach is capable of achieving 12 dB peak reductions and a 3.6 dB integrated reduction in radiated sound power from the stiffened panel.

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

    ERIC Educational Resources Information Center

    Newman, Robert B.

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

  6. Controlling system components with a sound card: A versatile inkjet fluid testing platform

    NASA Astrophysics Data System (ADS)

    Bognet, Brice; Guo, Yang; Ma, Anson W. K.

    2016-01-01

    In this paper, we demonstrate how to use a personal computer sound card to develop an experimental platform for evaluating the jettability and jetting behavior of inkjet fluids. The test fluid is driven out of a nozzle acoustically using a loudspeaker, forming a jet. The subsequent jet breakup process is then captured using a stroboscopic light source and a camera. Instead of using a delay generator as in previous work, the current setup uses a computer sound card and audio amplifier to (i) generate actuation waveforms of arbitrary shapes and (ii) synchronize the jet actuation and imaging with a time precision close to 5 μs. To correct for any signal distortions caused by the built-in high pass filters of the sound card and amplifier, a numerical filter is created and applied before sending the desired signal to the sound card. Such correction method does not require physically modifying the hardware of the sound card or amplifier and is applicable to different waveforms and filters provided that the transfer function is correctly identified. The platform has been tested using 20% (v/v) glycerol in water as a model fluid. Combining this platform with digital image analysis further enables a quantitative assessment of parameters such as the volumes and positions of the jet and drop that are important for quality control and development of new ink formulations.

  7. A lab-controlled simulation of a letter-speech sound binding deficit in dyslexia.

    PubMed

    Aravena, Sebastián; Snellings, Patrick; Tijms, Jurgen; van der Molen, Maurits W

    2013-08-01

    Dyslexic and non-dyslexic readers engaged in a short training aimed at learning eight basic letter-speech sound correspondences within an artificial orthography. We examined whether a letter-speech sound binding deficit is behaviorally detectable within the initial steps of learning a novel script. Both letter knowledge and word reading ability within the artificial script were assessed. An additional goal was to investigate the influence of instructional approach on the initial learning of letter-speech sound correspondences. We assigned children from both groups to one of three different training conditions: (a) explicit instruction, (b) implicit associative learning within a computer game environment, or (c) a combination of (a) and (b) in which explicit instruction is followed by implicit learning. Our results indicated that dyslexics were outperformed by the controls on a time-pressured binding task and a word reading task within the artificial orthography, providing empirical support for the view that a letter-speech sound binding deficit is a key factor in dyslexia. A combination of explicit instruction and implicit techniques proved to be a more powerful tool in the initial teaching of letter-sound correspondences than implicit training alone. PMID:23708733

  8. Controlling system components with a sound card: A versatile inkjet fluid testing platform.

    PubMed

    Bognet, Brice; Guo, Yang; Ma, Anson W K

    2016-01-01

    In this paper, we demonstrate how to use a personal computer sound card to develop an experimental platform for evaluating the jettability and jetting behavior of inkjet fluids. The test fluid is driven out of a nozzle acoustically using a loudspeaker, forming a jet. The subsequent jet breakup process is then captured using a stroboscopic light source and a camera. Instead of using a delay generator as in previous work, the current setup uses a computer sound card and audio amplifier to (i) generate actuation waveforms of arbitrary shapes and (ii) synchronize the jet actuation and imaging with a time precision close to 5 μs. To correct for any signal distortions caused by the built-in high pass filters of the sound card and amplifier, a numerical filter is created and applied before sending the desired signal to the sound card. Such correction method does not require physically modifying the hardware of the sound card or amplifier and is applicable to different waveforms and filters provided that the transfer function is correctly identified. The platform has been tested using 20% (v/v) glycerol in water as a model fluid. Combining this platform with digital image analysis further enables a quantitative assessment of parameters such as the volumes and positions of the jet and drop that are important for quality control and development of new ink formulations.

  9. Controlling system components with a sound card: A versatile inkjet fluid testing platform.

    PubMed

    Bognet, Brice; Guo, Yang; Ma, Anson W K

    2016-01-01

    In this paper, we demonstrate how to use a personal computer sound card to develop an experimental platform for evaluating the jettability and jetting behavior of inkjet fluids. The test fluid is driven out of a nozzle acoustically using a loudspeaker, forming a jet. The subsequent jet breakup process is then captured using a stroboscopic light source and a camera. Instead of using a delay generator as in previous work, the current setup uses a computer sound card and audio amplifier to (i) generate actuation waveforms of arbitrary shapes and (ii) synchronize the jet actuation and imaging with a time precision close to 5 μs. To correct for any signal distortions caused by the built-in high pass filters of the sound card and amplifier, a numerical filter is created and applied before sending the desired signal to the sound card. Such correction method does not require physically modifying the hardware of the sound card or amplifier and is applicable to different waveforms and filters provided that the transfer function is correctly identified. The platform has been tested using 20% (v/v) glycerol in water as a model fluid. Combining this platform with digital image analysis further enables a quantitative assessment of parameters such as the volumes and positions of the jet and drop that are important for quality control and development of new ink formulations. PMID:26827347

  10. Intratympanic manganese administration revealed sound intensity and frequency dependent functional activity in rat auditory pathway.

    PubMed

    Jin, Seong-Uk; Lee, Jae-Jun; Hong, Kwan Soo; Han, Mun; Park, Jang-Woo; Lee, Hui Joong; Lee, Sangheun; Lee, Kyu-Yup; Shin, Kyung Min; Cho, Jin Ho; Cheong, Chaejoon; Chang, Yongmin

    2013-09-01

    The cochlear plays a vital role in the sense and sensitivity of hearing; however, there is currently a lack of knowledge regarding the relationships between mechanical transduction of sound at different intensities and frequencies in the cochlear and the neurochemical processes that lead to neuronal responses in the central auditory system. In the current study, we introduced manganese-enhanced MRI (MEMRI), a convenient in vivo imaging method, for investigation of how sound, at different intensities and frequencies, is propagated from the cochlear to the central auditory system. Using MEMRI with intratympanic administration, we demonstrated differential manganese signal enhancements according to sound intensity and frequencies in the ascending auditory pathway of the rat after administration of intratympanic MnCl2.Compared to signal enhancement without explicit sound stimuli, auditory structures in the ascending auditory pathway showed stronger signal enhancement in rats who received sound stimuli of 10 and 40 kHz. In addition, signal enhancement with a stimulation frequency of 40 kHz was stronger than that with 10 kHz. Therefore, the results of this study seem to suggest that, in order to achieve an effective response to high sound intensity or frequency, more firing of auditory neurons, or firing of many auditory neurons together for the pooled neural activity is needed.

  11. Data Assimilation Experiments using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2008-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AlRS data. Version 5 contains accurate case-by-case error estimates for most derived products, which are also used for quality control. We have conducted forecast impact experiments assimilating AlRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the NASA FVGCM. Assimilation of quality controlled temperature profiles resulted in significantly improved forecast skill in both the Northern Hemisphere and Southern Hemisphere Extra-Tropics, compared to that obtained from analyses obtained when all data used operationally by NCEP except for AlRS data is assimilated. Experiments using different Quality Control thresholds for assimilation of AlRS temperature retrievals showed that a medium quality control threshold performed better than a tighter threshold, which provided better overall sounding accuracy; or a looser threshold, which provided better spatial coverage of accepted soundings. We are conducting more experiments to further optimize this balance of spatial coverage and sounding accuracy from the data assimilation perspective. In all cases, temperature soundings were assimilated well below cloud level in partially cloudy cases. The positive impact of assimilating AlRS derived atmospheric temperatures all but vanished when only AIRS stratospheric temperatures were assimilated. Forecast skill resulting from assimilation of AlRS radiances uncontaminated by clouds, instead of AlRS temperature soundings, was only slightly better than that resulting from assimilation of only stratospheric AlRS temperatures. This reduction in forecast skill is most likely the result of significant loss of tropospheric information when only AIRS radiances unaffected by clouds are used in the data assimilation process.

  12. Activities of the Institute of Sound and Vibration Research

    NASA Astrophysics Data System (ADS)

    Research in fluid dynamics and acoustics, vehicle noise, audiology and human effects, industrial noise, and noise and vibration control is summarized. Aircraft noise, underwater acoustics, damping of fiber reinforced materials and finite element methods are discussed.

  13. Active Outer Hair Cells Affect the Sound-Evoked Vibration of the Reticular Lamina

    NASA Astrophysics Data System (ADS)

    Jacob, Stefan; Fridberger, Anders

    2011-11-01

    It is well established that the organ of Corti uses active mechanisms to enhance its sensitivity and frequency selectivity. Two possible mechanisms have been identified, both capable of producing mechanical forces, which can alter the sound-evoked vibration of the hearing organ. However, little is known about the effect of these forces on the sound-evoked vibration pattern of the reticular lamina. Current injections into scala media were used to alter the amplitude of the active mechanisms in the apex of the guinea pig temporal bone. We used time-resolved confocal imaging to access the vibration pattern of individual outer hair cells. During positive current injection the the sound-evoked vibration of outer hair cell row three increased while row one showed a small decrease. Negative currents reversed the observed effect. We conclude that the outer hair cell mediated modification of reticular lamina vibration patterns could contribute to the inner hair cell stimulation.

  14. Diversity in sound pressure levels and estimated active space of resident killer whale vocalizations.

    PubMed

    Miller, Patrick J O

    2006-05-01

    Signal source intensity and detection range, which integrates source intensity with propagation loss, background noise and receiver hearing abilities, are important characteristics of communication signals. Apparent source levels were calculated for 819 pulsed calls and 24 whistles produced by free-ranging resident killer whales by triangulating the angles-of-arrival of sounds on two beamforming arrays towed in series. Levels in the 1-20 kHz band ranged from 131 to 168 dB re 1 microPa at 1 m, with differences in the means of different sound classes (whistles: 140.2+/-4.1 dB; variable calls: 146.6+/-6.6 dB; stereotyped calls: 152.6+/-5.9 dB), and among stereotyped call types. Repertoire diversity carried through to estimates of active space, with "long-range" stereotyped calls all containing overlapping, independently-modulated high-frequency components (mean estimated active space of 10-16 km in sea state zero) and "short-range" sounds (5-9 km) included all stereotyped calls without a high-frequency component, whistles, and variable calls. Short-range sounds are reported to be more common during social and resting behaviors, while long-range stereotyped calls predominate in dispersed travel and foraging behaviors. These results suggest that variability in sound pressure levels may reflect diverse social and ecological functions of the acoustic repertoire of killer whales.

  15. Semi-Supervised Active Learning for Sound Classification in Hybrid Learning Environments.

    PubMed

    Han, Wenjing; Coutinho, Eduardo; Ruan, Huabin; Li, Haifeng; Schuller, Björn; Yu, Xiaojie; Zhu, Xuan

    2016-01-01

    Coping with scarcity of labeled data is a common problem in sound classification tasks. Approaches for classifying sounds are commonly based on supervised learning algorithms, which require labeled data which is often scarce and leads to models that do not generalize well. In this paper, we make an efficient combination of confidence-based Active Learning and Self-Training with the aim of minimizing the need for human annotation for sound classification model training. The proposed method pre-processes the instances that are ready for labeling by calculating their classifier confidence scores, and then delivers the candidates with lower scores to human annotators, and those with high scores are automatically labeled by the machine. We demonstrate the feasibility and efficacy of this method in two practical scenarios: pool-based and stream-based processing. Extensive experimental results indicate that our approach requires significantly less labeled instances to reach the same performance in both scenarios compared to Passive Learning, Active Learning and Self-Training. A reduction of 52.2% in human labeled instances is achieved in both of the pool-based and stream-based scenarios on a sound classification task considering 16,930 sound instances. PMID:27627768

  16. Semi-Supervised Active Learning for Sound Classification in Hybrid Learning Environments

    PubMed Central

    Han, Wenjing; Coutinho, Eduardo; Li, Haifeng; Schuller, Björn; Yu, Xiaojie; Zhu, Xuan

    2016-01-01

    Coping with scarcity of labeled data is a common problem in sound classification tasks. Approaches for classifying sounds are commonly based on supervised learning algorithms, which require labeled data which is often scarce and leads to models that do not generalize well. In this paper, we make an efficient combination of confidence-based Active Learning and Self-Training with the aim of minimizing the need for human annotation for sound classification model training. The proposed method pre-processes the instances that are ready for labeling by calculating their classifier confidence scores, and then delivers the candidates with lower scores to human annotators, and those with high scores are automatically labeled by the machine. We demonstrate the feasibility and efficacy of this method in two practical scenarios: pool-based and stream-based processing. Extensive experimental results indicate that our approach requires significantly less labeled instances to reach the same performance in both scenarios compared to Passive Learning, Active Learning and Self-Training. A reduction of 52.2% in human labeled instances is achieved in both of the pool-based and stream-based scenarios on a sound classification task considering 16,930 sound instances. PMID:27627768

  17. Semi-Supervised Active Learning for Sound Classification in Hybrid Learning Environments.

    PubMed

    Han, Wenjing; Coutinho, Eduardo; Ruan, Huabin; Li, Haifeng; Schuller, Björn; Yu, Xiaojie; Zhu, Xuan

    2016-01-01

    Coping with scarcity of labeled data is a common problem in sound classification tasks. Approaches for classifying sounds are commonly based on supervised learning algorithms, which require labeled data which is often scarce and leads to models that do not generalize well. In this paper, we make an efficient combination of confidence-based Active Learning and Self-Training with the aim of minimizing the need for human annotation for sound classification model training. The proposed method pre-processes the instances that are ready for labeling by calculating their classifier confidence scores, and then delivers the candidates with lower scores to human annotators, and those with high scores are automatically labeled by the machine. We demonstrate the feasibility and efficacy of this method in two practical scenarios: pool-based and stream-based processing. Extensive experimental results indicate that our approach requires significantly less labeled instances to reach the same performance in both scenarios compared to Passive Learning, Active Learning and Self-Training. A reduction of 52.2% in human labeled instances is achieved in both of the pool-based and stream-based scenarios on a sound classification task considering 16,930 sound instances.

  18. Sounds Like Fun: Activities for Developing Phonological Awareness, Revised Edition

    ERIC Educational Resources Information Center

    Spector, Cecile Cyrul

    2009-01-01

    Kids love jokes--and teachers and SLPs love fast and easy ways to improve students' phonological awareness. That's why every elementary and middle-school SLP and educator needs this playful, effective activity book, packed with jokes and riddles that increase students' awareness of the phonemes that make up words. The perfect way to avoid "drill…

  19. Applications of Sound Spectrum Analysis

    ERIC Educational Resources Information Center

    Moran, Timothy

    2007-01-01

    The physics of sound is often studied in introductory physics class experiments involving a tube of resonating air. In typical setups, pistons control the length of a cylindrical space or a microphone is moved within a tube. While these activities are useful and can be made very quantitative, they don't directly demonstrate the sounds that are…

  20. Early Fishing Peoples of Puget Sound. Ocean Related Curriculum Activities. Revised Edition.

    ERIC Educational Resources Information Center

    McNutt, Nan

    The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers…

  1. Performances of Student Activism: Sound, Silence, Gender, and Dis/ability

    ERIC Educational Resources Information Center

    Pasque, Penny A.; Vargas, Juanita Gamez

    2014-01-01

    This chapter explores the various performances of activism by students through sound, silence, gender, and dis/ability and how these performances connect to social change efforts around issues such as human trafficking, homeless children, hunger, and children with varying abilities.

  2. Perceptual demand modulates activation of human auditory cortex in response to task-irrelevant sounds.

    PubMed

    Sabri, Merav; Humphries, Colin; Verber, Matthew; Mangalathu, Jain; Desai, Anjali; Binder, Jeffrey R; Liebenthal, Einat

    2013-09-01

    In the visual modality, perceptual demand on a goal-directed task has been shown to modulate the extent to which irrelevant information can be disregarded at a sensory-perceptual stage of processing. In the auditory modality, the effect of perceptual demand on neural representations of task-irrelevant sounds is unclear. We compared simultaneous ERPs and fMRI responses associated with task-irrelevant sounds across parametrically modulated perceptual task demands in a dichotic-listening paradigm. Participants performed a signal detection task in one ear (Attend ear) while ignoring task-irrelevant syllable sounds in the other ear (Ignore ear). Results revealed modulation of syllable processing by auditory perceptual demand in an ROI in middle left superior temporal gyrus and in negative ERP activity 130-230 msec post stimulus onset. Increasing the perceptual demand in the Attend ear was associated with a reduced neural response in both fMRI and ERP to task-irrelevant sounds. These findings are in support of a selection model whereby ongoing perceptual demands modulate task-irrelevant sound processing in auditory cortex.

  3. Active Noise Control for Dishwasher noise

    NASA Astrophysics Data System (ADS)

    Lee, Nokhaeng; Park, Youngjin

    2016-09-01

    The dishwasher is a useful home appliance and continually used for automatically washing dishes. It's commonly placed in the kitchen with built-in style for practicality and better use of space. In this environment, people are easily exposed to dishwasher noise, so it is an important issue for the consumers, especially for the people living in open and narrow space. Recently, the sound power levels of the noise are about 40 - 50 dBA. It could be achieved by removal of noise sources and passive means of insulating acoustical path. For more reduction, such a quiet mode with the lower speed of cycle has been introduced, but this deteriorates the washing capacity. Under this background, we propose active noise control for dishwasher noise. It is observed that the noise is propagating mainly from the lower part of the front side. Control speakers are placed in the part for the collocation. Observation part of estimating sound field distribution and control part of generating the anti-noise are designed for active noise control. Simulation result shows proposed active noise control scheme could have a potential application for dishwasher noise reduction.

  4. Comparing passive and active hearing: spectral analysis of transient sounds in bats.

    PubMed

    Goerlitz, Holger R; Hübner, Mathias; Wiegrebe, Lutz

    2008-06-01

    In vision, colour constancy allows the evaluation of the colour of objects independent of the spectral composition of a light source. In the auditory system, comparable mechanisms have been described that allows the evaluation of the spectral shape of sounds independent of the spectral composition of ambient background sounds. For echolocating bats, the evaluation of spectral shape is vitally important both for the analysis of external sounds and the analysis of the echoes of self-generated sonar emissions. Here, we investigated how the echolocating bat Phyllostomus discolor evaluates the spectral shape of transient sounds both in passive hearing and in echolocation as a specialized mode of active hearing. Bats were trained to classify transients of different spectral shape as low- or highpass. We then assessed how the spectral shape of an ambient background noise influenced the spontaneous classification of the transients. In the passive-hearing condition, the bats spontaneously changed their classification boundary depending on the spectral shape of the background. In the echo-acoustic condition, the classification boundary did not change although the background- and spectral-shape manipulations were identical in the two conditions. These data show that auditory processing differs between passive and active hearing: echolocation represents an independent mode of active hearing with its own rules of auditory spectral analysis.

  5. On the electric activity of superfluid helium at the excitation of first and second sound waves

    SciTech Connect

    Pashitskii, E. A. Gurin, A. A.

    2010-01-15

    We show that the electric activity of superfluid helium (HeII) observed in the experiments [3] during the excitation of standing second sound waves in an acoustic resonator can be described in terms of the phenomenological mechanism of the inertial polarization of atoms in a dielectric, in particular, in HeII, when the polarization field induced in the medium is proportional to the mechanical acceleration, by analogy with the Stewart-Tolman effect. The variable relative velocity w = v{sub n} - v{sub s} of the normal and superfluid HeII components that emerges in the second sound wave determines the mean group velocity of rotons, V{sub g} Almost-Equal-To w, with the density of the normal component related to their equilibrium number density in the temperature range 1.3 K {<=} T {<=} 2 K. Therefore, the acceleration of the 4He atoms involved in the formation of a roton excitation is proportional to the time derivative of the relative velocity.w. In this case, the linear local relations between the variable values of the electric induction, electric field strength, and polarization vector should be taken into account. As a result, the variable displacement current induced in the bulk of HeII and the corresponding potential difference do not depend on the anomalously low polarizability of liquid helium. This allows the ratio of the amplitudes of the temperature and potential oscillations in the second sound wave, which is almost independent of T in the above temperature range, consistent with experimental data to be obtained. At the same time, the absence of an electric response during the excitation of first sound waves in the linear regime is related to an insufficient power of the sound oscillations. Based on the experimental data on the excitation of first and second sounds, we have obtained estimates for the phenomenological coefficient of proportionality between the polarization vector and acceleration and for the drag coefficient of helium atoms by rotons in the

  6. Prevalence of different temporomandibular joint sounds, with emphasis on disc-displacement, in patients with temporomandibular disorders and controls.

    PubMed

    Elfving, Lars; Helkimo, Martti; Magnusson, Tomas

    2002-01-01

    Temporomandibular joint (TMJ) sounds are very common among patients with temporomandibular disorders (TMD), but also in non-patient populations. A variety of different causes to TMJ-sounds have been suggested e.g. arthrotic changes in the TMJs, anatomical variations, muscular incoordination and disc displacement. In the present investigation, the prevalence and type of different joint sounds were registered in 125 consecutive patients with suspected TMD and in 125 matched controls. Some kind of joint sound was recorded in 56% of the TMD patients and in 36% of the controls. The awareness of joint sounds was higher among TMD patients as compared to controls (88% and 60% respectively). The most common sound recorded in both groups was reciprocal clickings indicative of a disc displacement, while not one single case fulfilling the criteria for clicking due to a muscular incoordination was found. In the TMD group women with disc displacement reported sleeping on the stomach significantly more often than women without disc displacement did. An increased general joint laxity was found in 39% of the TMD patients with disc displacement, while this was found in only 9% of the patients with disc displacement in the control group. To conclude, disc displacement is probably the most common cause to TMJ sounds, while the existence of TMJ sounds due to a muscular incoordination can be questioned. Furthermore, sleeping on the stomach might be associated with disc displacement, while general joint laxity is probably not a causative factor, but a seeking care factor in patients with disc displacement.

  7. On the turbulence-generated sound and control of compressible mixing layers

    NASA Astrophysics Data System (ADS)

    Kleinman, Randall Ray

    A mixing layer is a common model used to study the noise generation and mixing characteristics of the near-nozzle region of jets. This work presents three separate but related studies that investigate sound generation and active control for noise mitigation and mixing enhancement of such mixing layers. High-fidelity direct numerical simulations of temporal and spatial mixing layers are used for this in two and three dimensions. The first study investigates the role of turbulence scales in generating the radiated far-field sound from temporally-developing, Mach 0.9 mixing layers. To do this, four mixing layers were simulated, starting from the same initial conditions but with Reynolds numbers that varied by a factor of twelve. Above a momentum thickness Reynolds number of 300, all the mixing layers radiate over 85 percent of the acoustic energy of the apparently asymptotically high-Reynolds-number value we are able to compute. Wavenumber spectra of turbulence energy and pressure show the expected Reynolds number dependence: the two highest Reynolds number simulations show evidence of an inertial range and Kolmogorov scaling at the highest wavenumbers. Farfield pressure spectra all decay much more rapidly with wavenumber than the corresponding near-field spectra and show significantly less sensitivity to Reynolds number. Low wavenumbers account for nearly all of the radiated acoustic energy. Implications of these results for jet noise large-eddy simulations are discussed. The second study uses direct numerical simulations of Mach 1.3 mixing layers to characterize the physical mechanisms of flow actuation by localized arc-filament plasma actuators. A validated numerical model of the actuator is devised and placed, as in corresponding experiments, in a cavity in the nozzle near its exit. A rapid Joule heating caused by the plasma is thought to be the root mechanism of flow actuation based upon experimental observation. Simulations show that in the confined space of the

  8. A double-panel active segmented partition module using decoupled analog feedback controllers: numerical model.

    PubMed

    Sagers, Jason D; Leishman, Timothy W; Blotter, Jonathan D

    2009-06-01

    Low-frequency sound transmission has long plagued the sound isolation performance of lightweight partitions. Over the past 2 decades, researchers have investigated actively controlled structures to prevent sound transmission from a source space into a receiving space. An approach using active segmented partitions (ASPs) seeks to improve low-frequency sound isolation capabilities. An ASP is a partition which has been mechanically and acoustically segmented into a number of small individually controlled modules. This paper provides a theoretical and numerical development of a single ASP module configuration, wherein each panel of the double-panel structure is independently actuated and controlled by an analog feedback controller. A numerical model is developed to estimate frequency response functions for the purpose of controller design, to understand the effects of acoustic coupling between the panels, to predict the transmission loss of the module in both passive and active states, and to demonstrate that the proposed ASP module will produce bidirectional sound isolation.

  9. Processes controlling the remobilization of surficial sediment and formation of sedimentary furrows in north-central Long Island Sound

    USGS Publications Warehouse

    Poppe, L.J.; Knebel, H. J.; Lewis, R.S.; DiGiacomo-Cohen, M. L.

    2002-01-01

    Sidescan sonar, bathymetric, subbottom, and bottom-photographic surveys and sediment sampling have improved our understanding of the processes that control the complex distribution of bottom sediments and benthic habitats in Long Island Sound. Although the deeper (>20 m) waters of the central Sound are long-term depositional areas characterized by relatively weak bottom-current regimes, our data reveal the localized presence of sedimentary furrows. These erosional bedforms occur in fine-grained cohesive sediments (silts and clayey silts), trend east-northeast, are irregularly spaced, and have indistinct troughs with gently sloping walls. The average width and relief of the furrows is 9.2 m and 0.4 m, respectively. The furrows average about 206 m long, but range in length from 30 m to over 1,300 m. Longitudinal ripples, bioturbation, and nutclam shell debris are common within the furrows. Although many of the furrows appear to end by gradually narrowing, some furrows show a "tuning fork" joining pattern. Most of these junctions open toward the east, indicating net westward sediment transport. However, a few junctions open toward the west suggesting that oscillating tidal currents are the dominant mechanism controlling furrow formation. Sedimentary furrows and longitudinal ripples typically form in environments which have recurring, directionally stable, and occasionally strong currents. The elongate geometry and regional bathymetry of Long Island Sound combine to constrain the dominant tidal and storm currents to east-west flow directions and permit the development of these bedforms. Through resuspension due to biological activity and the subsequent development of erosional bedforms, fine-grained cohesive sediment can be remobilized and made available for transport farther westward into the estuary.

  10. Processes controlling the remobilization of surficial sediment and formation of sedimentary furrows in North-Central Long Island Sound

    USGS Publications Warehouse

    Poppe, L.J.; Knebel, H. J.; Lewis, R.S.; DiGiacomo-Cohen, M. L.

    2002-01-01

    Sidescan sonar, bathymetric, subbottom, and bottom-photographic surveys and sediment sampling have improved our understanding of the processes that control the complex distribution of bottom sediments and benthic habitats in Long Island Sound. Although the deeper (>20 m) waters of the central Sound are long-term depositional areas characterized by relatively weak bottom-current regimes, our data reveal the localized presence of sedimentary furrows. These erosional bedforms occur in fine-grained cohesive sediments (silts and clayey silts), trend east-northeast, are irregularly spaced, and have indistinct troughs with gently sloping walls. The average width and relief of the furrows is 9.2 m and 0.4 m, respectively. The furrows average about 206 m long, but range in length from 30 m to over 1,300 m. Longitudinal ripples, bioturbation, and nutclam shell debris are common within the furrows. Although many of the furrows appear to end by gradually narrowing, some furrows show a "tuning fork" joining pattern. Most of these junctions open toward the east, indicating net westward sediment transport. However, a few junctions open toward the west suggesting that oscillating tidal currents are the dominant mechanism controlling furrow formation. Sedimentary furrows and longitudinal ripples typically form in environments which have recurring, directionally stable, and occasionally strong currents. The elongate geometry and regional bathymetry of Long Island Sound combine to constrain the dominant tidal and storm currents to east-west flow directions and permit the development of these bedforms. Through resuspension due to biological activity and the subsequent development of erosional bedforms, fine-grained cohesive sediment can be remobilized and made available for transport farther westward into the estuary.

  11. Music Training Enhances Rapid Neural Plasticity of N1 and P2 Source Activation for Unattended Sounds

    PubMed Central

    Seppänen, Miia; Hämäläinen, Jarmo; Pesonen, Anu-Katriina; Tervaniemi, Mari

    2012-01-01

    Neurocognitive studies have demonstrated that long-term music training enhances the processing of unattended sounds. It is not clear, however, whether music training also modulates rapid (within tens of minutes) neural plasticity for sound encoding. To study this phenomenon, we examined whether adult musicians display enhanced rapid neural plasticity compared to non-musicians. More specifically, we compared the modulation of P1, N1, and P2 responses to standard sounds between four unattended passive blocks. Among the standard sounds, infrequently presented deviant sounds were presented (the so-called oddball paradigm). In the middle of the experiment (after two blocks), an active task was presented. Source analysis for event-related potentials (ERPs) showed that N1 and P2 source activation was selectively decreased in musicians after 15 min of passive exposure to sounds and that P2 source activation was found to be re-enhanced after the active task in musicians. Additionally, ERP analysis revealed that in both musicians and non-musicians, P2 ERP amplitude was enhanced after 15 min of passive exposure but only at the frontal electrodes. Furthermore, in musicians, the N1 ERP was enhanced after the active discrimination task but only at the parietal electrodes. Musical training modulates the rapid neural plasticity reflected in N1 and P2 source activation for unattended regular standard sounds. Enhanced rapid plasticity of N1 and P2 is likely to reflect faster auditory perceptual learning in musicians. PMID:22435057

  12. Vespertilionid bats control the width of their biosonar sound beam dynamically during prey pursuit

    PubMed Central

    Jakobsen, Lasse; Surlykke, Annemarie

    2010-01-01

    Animals using sound for communication emit directional signals, focusing most acoustic energy in one direction. Echolocating bats are listening for soft echoes from insects. Therefore, a directional biosonar sound beam greatly increases detection probability in the forward direction and decreases off-axis echoes. However, high directionality has context-specific disadvantages: at close range the detection space will be vastly reduced, making a broad beam favorable. Hence, a flexible system would be very advantageous. We investigated whether bats can dynamically change directionality of their biosonar during aerial pursuit of insects. We trained five Myotis daubentonii and one Eptesicus serotinus to capture tethered mealworms and recorded their echolocation signals with a multimicrophone array. The results show that the bats broaden the echolocation beam drastically in the terminal phase of prey pursuit. M. daubentonii increased the half-amplitude angle from approximately 40° to approximately 90° horizontally and from approximately 45° to more than 90° vertically. The increase in beam width is achieved by lowering the frequency by roughly one octave from approximately 55 kHz to approximately 27.5 kHz. The E. serotinus showed beam broadening remarkably similar to that of M. daubentonii. Our results demonstrate dynamic control of beam width in both species. Hence, we propose directionality as an explanation for the frequency decrease observed in the buzz of aerial hawking vespertilionid bats. We predict that future studies will reveal dynamic control of beam width in a broad range of acoustically communicating animals. PMID:20643943

  13. Depth sounding lidar: an overview of Swedish activities and future prospects

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove K.; Koppari, Kurt R.

    1996-11-01

    This paper describes the depth sounding activities in Sweden. These include the development of a helicopter borne lidar called FLASH as well as instrumentation for in situ measurement of the optical water parameters as well as modeling efforts of depth sounding lidar performance. The FLASH system has been further developed into two operational systems called Hawk Eye with Saab Dynamics as the main contractor and Optech Inc. as the main subcontractor. Data collection and evaluation from Hawk Eye will be discussed. The Swedish Defence Research Establishment (FOA) was a member of the Hawk Eye project team together with the National Maritime Administration, the Royal Swedish Navy and the Defence Material Administration. Together with the Swedish Maritime Administration, FOA has been engaged in analysis of lidar data to determine system performance and possible ways to optimize that in relation to lidar parameters and anticipated bottom depth and topography. Examples from that analysis will be presented. The test analysis so far strongly supports the depth sounding lidar technology as being a rapid and accurate sounder fulfilling the requirement by International Maritime Office on depth accuracy.

  14. Universal mechanisms of sound production and control in birds and mammals.

    PubMed

    Elemans, C P H; Rasmussen, J H; Herbst, C T; Düring, D N; Zollinger, S A; Brumm, H; Srivastava, K; Svane, N; Ding, M; Larsen, O N; Sober, S J; Švec, J G

    2015-01-01

    As animals vocalize, their vocal organ transforms motor commands into vocalizations for social communication. In birds, the physical mechanisms by which vocalizations are produced and controlled remain unresolved because of the extreme difficulty in obtaining in vivo measurements. Here, we introduce an ex vivo preparation of the avian vocal organ that allows simultaneous high-speed imaging, muscle stimulation and kinematic and acoustic analyses to reveal the mechanisms of vocal production in birds across a wide range of taxa. Remarkably, we show that all species tested employ the myoelastic-aerodynamic (MEAD) mechanism, the same mechanism used to produce human speech. Furthermore, we show substantial redundancy in the control of key vocal parameters ex vivo, suggesting that in vivo vocalizations may also not be specified by unique motor commands. We propose that such motor redundancy can aid vocal learning and is common to MEAD sound production across birds and mammals, including humans.

  15. Using the speed of sound for in situ calibration of mass flow controllers

    NASA Astrophysics Data System (ADS)

    Wajid, Abdul

    2000-09-01

    Mass flow controllers (MFCs) are widely used for precise delivery of process gases, particularly in semiconductor industry. Often a specific MFC is factory calibrated with an inert gas. In order to estimate the actual delivery of process gases, which may be corrosive and hazardous, a multiplier called the gas calibration factor is used. Moreover, a single MFC may be used to deliver multiple gases and its thermal characteristics do change over time. We describe here a very simple method of calibrating thermal mass flow controllers, in situ, with actual process gases, utilizing the speed of sound. We have used a commercially available instrument that uses acoustic resonance technique for determining the composition of a binary gas mixture.

  16. Discrimination of speech sounds by children with dyslexia: comparisons with chronological age and reading level controls.

    PubMed

    Bogliotti, C; Serniclaes, W; Messaoud-Galusi, S; Sprenger-Charolles, L

    2008-10-01

    Previous studies have shown that children suffering from developmental dyslexia have a deficit in categorical perception of speech sounds. The aim of the current study was to better understand the nature of this categorical perception deficit. In this study, categorical perception skills of children with dyslexia were compared with those of chronological age and reading level controls. Children identified and discriminated /do-to/ syllables along a voice onset time (VOT) continuum. Results showed that children with dyslexia discriminated among phonemically contrastive pairs less accurately than did chronological age and reading level controls and also showed higher sensitivity in the discrimination of allophonic contrasts. These results suggest that children with dyslexia perceive speech with allophonic units rather than phonemic units. The origin of allophonic perception in the course of perceptual development and its implication for reading acquisition are discussed. PMID:18462745

  17. Universal mechanisms of sound production and control in birds and mammals

    PubMed Central

    Elemans, C.P.H; Rasmussen, J.H.; Herbst, C.T.; Düring, D.N.; Zollinger, S.A.; Brumm, H.; Srivastava, K.; Svane, N.; Ding, M.; Larsen, O.N.; Sober, S.J.; Švec, J.G.

    2015-01-01

    As animals vocalize, their vocal organ transforms motor commands into vocalizations for social communication. In birds, the physical mechanisms by which vocalizations are produced and controlled remain unresolved because of the extreme difficulty in obtaining in vivo measurements. Here, we introduce an ex vivo preparation of the avian vocal organ that allows simultaneous high-speed imaging, muscle stimulation and kinematic and acoustic analyses to reveal the mechanisms of vocal production in birds across a wide range of taxa. Remarkably, we show that all species tested employ the myoelastic-aerodynamic (MEAD) mechanism, the same mechanism used to produce human speech. Furthermore, we show substantial redundancy in the control of key vocal parameters ex vivo, suggesting that in vivo vocalizations may also not be specified by unique motor commands. We propose that such motor redundancy can aid vocal learning and is common to MEAD sound production across birds and mammals, including humans. PMID:26612008

  18. Universal mechanisms of sound production and control in birds and mammals.

    PubMed

    Elemans, C P H; Rasmussen, J H; Herbst, C T; Düring, D N; Zollinger, S A; Brumm, H; Srivastava, K; Svane, N; Ding, M; Larsen, O N; Sober, S J; Švec, J G

    2015-01-01

    As animals vocalize, their vocal organ transforms motor commands into vocalizations for social communication. In birds, the physical mechanisms by which vocalizations are produced and controlled remain unresolved because of the extreme difficulty in obtaining in vivo measurements. Here, we introduce an ex vivo preparation of the avian vocal organ that allows simultaneous high-speed imaging, muscle stimulation and kinematic and acoustic analyses to reveal the mechanisms of vocal production in birds across a wide range of taxa. Remarkably, we show that all species tested employ the myoelastic-aerodynamic (MEAD) mechanism, the same mechanism used to produce human speech. Furthermore, we show substantial redundancy in the control of key vocal parameters ex vivo, suggesting that in vivo vocalizations may also not be specified by unique motor commands. We propose that such motor redundancy can aid vocal learning and is common to MEAD sound production across birds and mammals, including humans. PMID:26612008

  19. Generation and control of sound bullets with a nonlinear acoustic lens

    PubMed Central

    Spadoni, Alessandro; Daraio, Chiara

    2010-01-01

    Acoustic lenses are employed in a variety of applications, from biomedical imaging and surgery to defense systems and damage detection in materials. Focused acoustic signals, for example, enable ultrasonic transducers to image the interior of the human body. Currently however the performance of acoustic devices is limited by their linear operational envelope, which implies relatively inaccurate focusing and low focal power. Here we show a dramatic focusing effect and the generation of compact acoustic pulses (sound bullets) in solid and fluid media, with energies orders of magnitude greater than previously achievable. This focusing is made possible by a tunable, nonlinear acoustic lens, which consists of ordered arrays of granular chains. The amplitude, size, and location of the sound bullets can be controlled by varying the static precompression of the chains. Theory and numerical simulations demonstrate the focusing effect, and photoelasticity experiments corroborate it. Our nonlinear lens permits a qualitatively new way of generating high-energy acoustic pulses, which may improve imaging capabilities through increased accuracy and signal-to-noise ratios and may lead to more effective nonintrusive scalpels, for example, for cancer treatment. PMID:20368461

  20. Generation and control of sound bullets with a nonlinear acoustic lens.

    PubMed

    Spadoni, Alessandro; Daraio, Chiara

    2010-04-20

    Acoustic lenses are employed in a variety of applications, from biomedical imaging and surgery to defense systems and damage detection in materials. Focused acoustic signals, for example, enable ultrasonic transducers to image the interior of the human body. Currently however the performance of acoustic devices is limited by their linear operational envelope, which implies relatively inaccurate focusing and low focal power. Here we show a dramatic focusing effect and the generation of compact acoustic pulses (sound bullets) in solid and fluid media, with energies orders of magnitude greater than previously achievable. This focusing is made possible by a tunable, nonlinear acoustic lens, which consists of ordered arrays of granular chains. The amplitude, size, and location of the sound bullets can be controlled by varying the static precompression of the chains. Theory and numerical simulations demonstrate the focusing effect, and photoelasticity experiments corroborate it. Our nonlinear lens permits a qualitatively new way of generating high-energy acoustic pulses, which may improve imaging capabilities through increased accuracy and signal-to-noise ratios and may lead to more effective nonintrusive scalpels, for example, for cancer treatment. PMID:20368461

  1. Investigation on the reproduction performance versus acoustic contrast control in sound field synthesis.

    PubMed

    Bai, Mingsian R; Wen, Jheng-Ciang; Hsu, Hoshen; Hua, Yi-Hsin; Hsieh, Yu-Hao

    2014-10-01

    A sound reconstruction system is proposed for audio reproduction with extended sweet spot and reduced reflections. An equivalent source method (ESM)-based sound field synthesis (SFS) approach, with the aid of dark zone minimization is adopted in the study. Conventional SFS that is based on the free-field assumption suffers from synthesis error due to boundary reflections. To tackle the problem, the proposed system utilizes convex optimization in designing array filters with both reproduction performance and acoustic contrast taken into consideration. Control points are deployed in the dark zone to minimize the reflections from the walls. Two approaches are employed to constrain the pressure and velocity in the dark zone. Pressure matching error (PME) and acoustic contrast (AC) are used as performance measures in simulations and experiments for a rectangular loudspeaker array. Perceptual Evaluation of Audio Quality (PEAQ) is also used to assess the audio reproduction quality. The results show that the pressure-constrained (PC) method yields better acoustic contrast, but poorer reproduction performance than the pressure-velocity constrained (PVC) method. A subjective listening test also indicates that the PVC method is the preferred method in a live room.

  2. How does high-frequency sound or vibration activate vestibular receptors?

    PubMed

    Curthoys, I S; Grant, J W

    2015-03-01

    The mechanism by which vestibular neural phase locking occurs and how it relates to classical otolith mechanics is unclear. Here, we put forward the hypothesis that sound and vibration both cause fluid pressure waves in the inner ear and that it is these pressure waves which displace the hair bundles on vestibular receptor hair cells and result in activation of type I receptor hair cells and phase locking of the action potentials in the irregular vestibular afferents, which synapse on type I receptors. This idea has been suggested since the early neural recordings and recent results give it greater credibility.

  3. Active control of automotive fan noise

    NASA Astrophysics Data System (ADS)

    Gerard, Anthony; Berry, Alain; Masson, Patrice

    2002-11-01

    Active control for globally reducing the noise radiated by automotive axial engine cooling fans is investigated. First, an aeroacoutic model of the fan is combined with acoustic directivity measurements to derive a distribution of equivalent dipole sources on the fan surface. The results reveal that the fan behaves like a distributed dipole at blade passage tones when the upstream flow through the fan is spatially nonuniform. Numerical simulations of active noise control in the free field have been carried out using the previous aeroacoustic model of the fan and a dipole secondary source in front of the fan. The numerical results show that a single dipole control source is effective in globally controlling the sound radiation of the fan at the blade passage frequency and its first harmonic. Last, an experimental investigation of active control is presented. It consists of a SISO feedforward configuration with either a LMS algorithm (for FIR filters) or a back-retropopagation algorithm (for neural networks) using the Simulink/Dspace environment for real-time implementation.

  4. An active control strategy for achieving weak radiator structures

    SciTech Connect

    Naghshineh, K. . Acoustics and Radar Technology Lab.); Koopmann, G.H. . Center for Acoustics and Vibration)

    1994-01-01

    A general control strategy is presented for active suppression of total radiated sound power from harmonically excited structures based on the measurement of their response. Using the measured response of the structure together with knowledge of its structural mobility, and equivalent primary excitation force is found at discrete points along the structure. Using this equivalent primary force and performing a quadratic optimization of the power radiated form the structure, a set of control forces is found at selected points on the structure that results in minimum radiated sound power. A numerical example of this strategy is presented for a simply supported beam in a rigid baffle excited by a harmonic plane wave incident at an oblique angle. A comparison of the response of the beam with and without control forces shows a large reduction in the controlled response displacement magnitude. In addition, as the result of the action of the control forces, the magnitude of the wave number spectrum of the beam's response in the supersonic region is decreased substantially. The effect of the number and location of the actuators on reductions in sound power level is also studied. The actuators located at the anti-nodes of structural modes within the supersonic region together with those located near boundaries are found to be the most effective in controlling the radiation of sound from a structure.

  5. Use of Quality Controlled AIRS Temperature Soundings to Improve Forecast Skill

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste; Iredell, Lena

    2010-01-01

    AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. Also included are the clear column radiances used to derive these products which are representative of the radiances AIRS would have seen if there were no clouds in the field of view. All products also have error estimates. The sounding goals of AIRS are to produce 1 km tropospheric layer mean temperatures with an rms error of 1K, and layer precipitable water with an rms error of 20 percent, in cases with up to 90 percent effective cloud cover. The products are designed for data assimilation purposes for the improvement of numerical weather prediction, as well as for the study of climate and meteorological processes. With regard to data assimilation, one can use either the products themselves or the clear column radiances from which the products were derived. The AIRS Version 5 retrieval algorithm is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates for retrieved quantities and clear column radiances, and the use of these error estimates for Quality Control. The temperature profile error estimates are used to determine a case-by-case characteristic pressure pbest, down to which the profile is considered acceptable for data assimilation purposes. The characteristic pressure p(sub best) is determined by comparing the case dependent error estimate (delta)T(p) to the threshold values (Delta)T(p). The AIRS Version 5 data set provides error estimates of T(p) at all levels, and also profile dependent values of pbest based

  6. On-line Monitoring and Active Control for Transformer Noise

    NASA Astrophysics Data System (ADS)

    Liang, Jiabi; Zhao, Tong; Tian, Chun; Wang, Xia; He, Zhenhua; Duan, Lunfeng

    This paper introduces the system for on-line monitoring and active noise control towards the transformer noise based on LabVIEW and the hardware equipment including the hardware and software. For the hardware part, it is mainly focused on the composition and the role of hardware devices, as well as the mounting location in the active noise control experiment. And the software part introduces the software flow chats, the measurement and analysis module for the sound pressure level including A, B, C weighting methods, the 1/n octave spectrum and the power spectrum, active noise control module and noise data access module.

  7. Historical Patterns and Drivers of Spatial Changes in Recreational Fishing Activity in Puget Sound, Washington

    PubMed Central

    Beaudreau, Anne H.; Whitney, Emily J.

    2016-01-01

    Small-scale fisheries are the primary users of many coastal fish stocks; yet, spatial and temporal patterns of recreational and subsistence fishing in coastal marine ecosystems are poorly documented. Knowledge about the spatial distribution of fishing activities can inform place-based management that balances species conservation with opportunities for recreation and subsistence. We used a participatory mapping approach to document changes in spatial fishing patterns of 80 boat-based recreational anglers from 1950 to 2010 in Puget Sound, Washington, USA. Hand-drawn fishing areas for salmon, rockfishes, flatfishes, and crabs were digitized and analyzed in a Geographic Information System. We found that recreational fishing has spanned the majority of Puget Sound since the 1950s, with the heaviest use limited to small areas of central and northern Puget Sound. People are still fishing in the same places they were decades ago, with relatively little change in specific locations despite widespread declines in salmon and bottomfish populations during the second half of the 20th century. While the location of core fishing areas remained consistent, the size of those areas and intensity of use changed over time. The size of fishing areas increased through the 2000s for salmon but declined after the 1970s and 1980s for rockfishes, flatfishes, and crabs. Our results suggest that the spatial extent of recreational bottomfishing increased after the 1960s, when the availability of motorized vessels and advanced fish-finding technologies allowed anglers to expand their scope beyond localized angling from piers and boathouses. Respondents offered a wide range of reasons for shifts in fishing areas over time, reflecting substantial individual variation in motivations and behaviors. Changes in fishing areas were most commonly attributed to changes in residence and declines in target species and least tied to fishery regulations, despite the implementation of at least 25 marine

  8. Historical Patterns and Drivers of Spatial Changes in Recreational Fishing Activity in Puget Sound, Washington.

    PubMed

    Beaudreau, Anne H; Whitney, Emily J

    2016-01-01

    Small-scale fisheries are the primary users of many coastal fish stocks; yet, spatial and temporal patterns of recreational and subsistence fishing in coastal marine ecosystems are poorly documented. Knowledge about the spatial distribution of fishing activities can inform place-based management that balances species conservation with opportunities for recreation and subsistence. We used a participatory mapping approach to document changes in spatial fishing patterns of 80 boat-based recreational anglers from 1950 to 2010 in Puget Sound, Washington, USA. Hand-drawn fishing areas for salmon, rockfishes, flatfishes, and crabs were digitized and analyzed in a Geographic Information System. We found that recreational fishing has spanned the majority of Puget Sound since the 1950s, with the heaviest use limited to small areas of central and northern Puget Sound. People are still fishing in the same places they were decades ago, with relatively little change in specific locations despite widespread declines in salmon and bottomfish populations during the second half of the 20th century. While the location of core fishing areas remained consistent, the size of those areas and intensity of use changed over time. The size of fishing areas increased through the 2000s for salmon but declined after the 1970s and 1980s for rockfishes, flatfishes, and crabs. Our results suggest that the spatial extent of recreational bottomfishing increased after the 1960s, when the availability of motorized vessels and advanced fish-finding technologies allowed anglers to expand their scope beyond localized angling from piers and boathouses. Respondents offered a wide range of reasons for shifts in fishing areas over time, reflecting substantial individual variation in motivations and behaviors. Changes in fishing areas were most commonly attributed to changes in residence and declines in target species and least tied to fishery regulations, despite the implementation of at least 25 marine

  9. Biological effect of audible sound control on mung bean (Vigna radiate) sprout.

    PubMed

    Cai, W; He, H; Zhu, S; Wang, N

    2014-01-01

    Audible sound (20-20000 Hz) widely exists in natural world. However, the interaction between audible sound and the growth of plants is usually neglected in biophysics research. Not much effort has been put forth in studying the relation of plant and audible sound. In this work, the effect of audible sound on germination and growth of mung bean (Vigna radiate) was studied under laboratory condition. Audible sound ranging 1000-1500 Hz, 1500-2000 Hz, and 2000-2500 Hz and intensities [80 dB (A), 90 dB (A), 100 dB (A)] were used to stimulate mung bean for 72 hours. The growth of mung bean was evaluated in terms of mean germination time, total length, and total fresh weight. Experimental results indicated that the sound wave can reduce the germination period of mung bean and the mung bean under treatments of sound with intensity around 90 dB and frequency around 2000 Hz and significant increase in growth. Audible sound treatment can promote the growth of mung bean differently for distinct frequency and intensity. The study provides us with a way to understand the effects and rules of sound field on plant growth and a new way to improve the production of mung bean.

  10. Biological Effect of Audible Sound Control on Mung Bean (Vigna radiate) Sprout

    PubMed Central

    Cai, W.; He, H.; Zhu, S.; Wang, N.

    2014-01-01

    Audible sound (20–20000 Hz) widely exists in natural world. However, the interaction between audible sound and the growth of plants is usually neglected in biophysics research. Not much effort has been put forth in studying the relation of plant and audible sound. In this work, the effect of audible sound on germination and growth of mung bean (Vigna radiate) was studied under laboratory condition. Audible sound ranging 1000–1500 Hz, 1500–2000 Hz, and 2000–2500 Hz and intensities [80 dB (A), 90 dB (A), 100 dB (A)] were used to stimulate mung bean for 72 hours. The growth of mung bean was evaluated in terms of mean germination time, total length, and total fresh weight. Experimental results indicated that the sound wave can reduce the germination period of mung bean and the mung bean under treatments of sound with intensity around 90 dB and frequency around 2000 Hz and significant increase in growth. Audible sound treatment can promote the growth of mung bean differently for distinct frequency and intensity. The study provides us with a way to understand the effects and rules of sound field on plant growth and a new way to improve the production of mung bean. PMID:25170517

  11. Biological effect of audible sound control on mung bean (Vigna radiate) sprout.

    PubMed

    Cai, W; He, H; Zhu, S; Wang, N

    2014-01-01

    Audible sound (20-20000 Hz) widely exists in natural world. However, the interaction between audible sound and the growth of plants is usually neglected in biophysics research. Not much effort has been put forth in studying the relation of plant and audible sound. In this work, the effect of audible sound on germination and growth of mung bean (Vigna radiate) was studied under laboratory condition. Audible sound ranging 1000-1500 Hz, 1500-2000 Hz, and 2000-2500 Hz and intensities [80 dB (A), 90 dB (A), 100 dB (A)] were used to stimulate mung bean for 72 hours. The growth of mung bean was evaluated in terms of mean germination time, total length, and total fresh weight. Experimental results indicated that the sound wave can reduce the germination period of mung bean and the mung bean under treatments of sound with intensity around 90 dB and frequency around 2000 Hz and significant increase in growth. Audible sound treatment can promote the growth of mung bean differently for distinct frequency and intensity. The study provides us with a way to understand the effects and rules of sound field on plant growth and a new way to improve the production of mung bean. PMID:25170517

  12. National Report Switzerland: Sounding Rocket and Balloon Activities and Related Research in Switzerland 2013-2015

    NASA Astrophysics Data System (ADS)

    Egli, M.

    2015-09-01

    , particularly in 2014. In order to keep the stations attractive to researchers from all over the world, investment in infrastructure is necessary. New instruments were recently installed at the Jungfrau East Ridge, for example, that now allow for the recording of additional climate and environmental data. A short summary of a few Swiss projects within the framework of sounding rocket and balloon activities and related research performed between 2013 and 2015 is provided in the following paragraphs.

  13. Active control of convection

    SciTech Connect

    Bau, H.H.

    1995-12-31

    Using stability theory, numerical simulations, and in some instances experiments, it is demonstrated that the critical Rayleigh number for the bifurcation (1) from the no-motion (conduction) state to the motion state and (2) from time-independent convection to time-dependent, oscillatory convection in the thermal convection loop and Rayleigh-Benard problems can be significantly increased or decreased. This is accomplished through the use of a feedback controller effectuating small perturbations in the boundary data. The controller consists of sensors which detect deviations in the fluid`s temperature from the motionless, conductive values and then direct actuators to respond to these deviations in such a way as to suppress the naturally occurring flow instabilities. Actuators which modify the boundary`s temperature/heat flux are considered. The feedback controller can also be used to control flow patterns and generate complex dynamic behavior at relatively low Rayleigh numbers.

  14. Frequencies of Inaudible High-Frequency Sounds Differentially Affect Brain Activity: Positive and Negative Hypersonic Effects

    PubMed Central

    Fukushima, Ariko; Yagi, Reiko; Kawai, Norie; Honda, Manabu; Nishina, Emi; Oohashi, Tsutomu

    2014-01-01

    The hypersonic effect is a phenomenon in which sounds containing significant quantities of non-stationary high-frequency components (HFCs) above the human audible range (max. 20 kHz) activate the midbrain and diencephalon and evoke various physiological, psychological and behavioral responses. Yet important issues remain unverified, especially the relationship existing between the frequency of HFCs and the emergence of the hypersonic effect. In this study, to investigate the relationship between the hypersonic effect and HFC frequencies, we divided an HFC (above 16 kHz) of recorded gamelan music into 12 band components and applied them to subjects along with an audible component (below 16 kHz) to observe changes in the alpha2 frequency component (10–13 Hz) of spontaneous EEGs measured from centro-parieto-occipital regions (Alpha-2 EEG), which we previously reported as an index of the hypersonic effect. Our results showed reciprocal directional changes in Alpha-2 EEGs depending on the frequency of the HFCs presented with audible low-frequency component (LFC). When an HFC above approximately 32 kHz was applied, Alpha-2 EEG increased significantly compared to when only audible sound was applied (positive hypersonic effect), while, when an HFC below approximately 32 kHz was applied, the Alpha-2 EEG decreased (negative hypersonic effect). These findings suggest that the emergence of the hypersonic effect depends on the frequencies of inaudible HFC. PMID:24788141

  15. Frequencies of inaudible high-frequency sounds differentially affect brain activity: positive and negative hypersonic effects.

    PubMed

    Fukushima, Ariko; Yagi, Reiko; Kawai, Norie; Honda, Manabu; Nishina, Emi; Oohashi, Tsutomu

    2014-01-01

    The hypersonic effect is a phenomenon in which sounds containing significant quantities of non-stationary high-frequency components (HFCs) above the human audible range (max. 20 kHz) activate the midbrain and diencephalon and evoke various physiological, psychological and behavioral responses. Yet important issues remain unverified, especially the relationship existing between the frequency of HFCs and the emergence of the hypersonic effect. In this study, to investigate the relationship between the hypersonic effect and HFC frequencies, we divided an HFC (above 16 kHz) of recorded gamelan music into 12 band components and applied them to subjects along with an audible component (below 16 kHz) to observe changes in the alpha2 frequency component (10-13 Hz) of spontaneous EEGs measured from centro-parieto-occipital regions (Alpha-2 EEG), which we previously reported as an index of the hypersonic effect. Our results showed reciprocal directional changes in Alpha-2 EEGs depending on the frequency of the HFCs presented with audible low-frequency component (LFC). When an HFC above approximately 32 kHz was applied, Alpha-2 EEG increased significantly compared to when only audible sound was applied (positive hypersonic effect), while, when an HFC below approximately 32 kHz was applied, the Alpha-2 EEG decreased (negative hypersonic effect). These findings suggest that the emergence of the hypersonic effect depends on the frequencies of inaudible HFC.

  16. Measurement of energetic radiation caused by thunderstorm activities by a sounding balloon and ground observation

    NASA Astrophysics Data System (ADS)

    Torii, T.

    2015-12-01

    Energetic radiation caused by thunderstorm activity is observed at various places, such as the ground, high mountain areas, and artificial satellites. In order to investigate the radiation source and its energy distribution, we measured energetic radiation by a sounding balloon, and the ground observation. On the measurement inside/above the thundercloud, we conducted a sounding observation using a radiosonde mounted two GM tubes (for gamma-rays, and for beta/gamma-rays), in addition to meteorological instruments. The balloon passed through a region of strong echoes in a thundercloud shown by radar image, at which time an increase in counting rate of the GM tube about 2 orders of magnitude occurred at the altitude from 5 km to 7.5 km. Furthermore, the counting rate of two GM tubes indicated the tendency different depending on movement of a balloon. This result suggests that the ratio for the gamma-rays (energetic photons) of the beta-rays (energetic electrons) varies according to the place in the thundercloud. Furthermore, we carried out a ground observation of the energetic gamma rays during winter thunderstorm at a coastal area facing the Sea of Japan. Two types of the energetic radiation have been observed at this time. We report the outline of these measurements and analysis in the session of the AGU meeting.

  17. Active weld control

    NASA Technical Reports Server (NTRS)

    Powell, Bradley W.; Burroughs, Ivan A.

    1994-01-01

    Through the two phases of this contract, sensors for welding applications and parameter extraction algorithms have been developed. These sensors form the foundation of a weld control system which can provide action weld control through the monitoring of the weld pool and keyhole in a VPPA welding process. Systems of this type offer the potential of quality enhancement and cost reduction (minimization of rework on faulty welds) for high-integrity welding applications. Sensors for preweld and postweld inspection, weld pool monitoring, keyhole/weld wire entry monitoring, and seam tracking were developed. Algorithms for signal extraction were also developed and analyzed to determine their application to an adaptive weld control system. The following sections discuss findings for each of the three sensors developed under this contract: (1) weld profiling sensor; (2) weld pool sensor; and (3) stereo seam tracker/keyhole imaging sensor. Hardened versions of these sensors were designed and built under this contract. A control system, described later, was developed on a multiprocessing/multitasking operating system for maximum power and flexibility. Documentation for sensor mechanical and electrical design is also included as appendices in this report.

  18. Active noise control: A tutorial for HVAC designers

    SciTech Connect

    Gelin, L.J.

    1997-08-01

    This article will identify the capabilities and limitations of ANC in its application to HVAC noise control. ANC can be used in ducted HVAC systems to cancel ductborne, low-frequency fan noise by injecting sound waves of equal amplitude and opposite phase into an air duct, as close as possible to the source of the unwanted noise. Destructive interference of the fan noise and injected noise results in sound cancellation. The noise problems that it solves are typically described as rumble, roar or throb, all of which are difficult to address using traditional noise control methods. This article will also contrast the use of active against passive noise control techniques. The main differences between the two noise control measures are acoustic performance, energy consumption, and design flexibility. The article will first present the fundamentals and basic physics of ANC. The application to real HVAC systems will follow.

  19. Knowledge About Sounds-Context-Specific Meaning Differently Activates Cortical Hemispheres, Auditory Cortical Fields, and Layers in House Mice.

    PubMed

    Geissler, Diana B; Schmidt, H Sabine; Ehret, Günter

    2016-01-01

    Activation of the auditory cortex (AC) by a given sound pattern is plastic, depending, in largely unknown ways, on the physiological state and the behavioral context of the receiving animal and on the receiver's experience with the sounds. Such plasticity can be inferred when house mouse mothers respond maternally to pup ultrasounds right after parturition and naïve females have to learn to respond. Here we use c-FOS immunocytochemistry to quantify highly activated neurons in the AC fields and layers of seven groups of mothers and naïve females who have different knowledge about and are differently motivated to respond to acoustic models of pup ultrasounds of different behavioral significance. Profiles of FOS-positive cells in the AC primary fields (AI, AAF), the ultrasonic field (UF), the secondary field (AII), and the dorsoposterior field (DP) suggest that activation reflects in AI, AAF, and UF the integration of sound properties with animal state-dependent factors, in the higher-order field AII the news value of a given sound in the behavioral context, and in the higher-order field DP the level of maternal motivation and, by left-hemisphere activation advantage, the recognition of the meaning of sounds in the given context. Anesthesia reduced activation in all fields, especially in cortical layers 2/3. Thus, plasticity in the AC is field-specific preparing different output of AC fields in the process of perception, recognition and responding to communication sounds. Further, the activation profiles of the auditory cortical fields suggest the differentiation between brains hormonally primed to know (mothers) and brains which acquired knowledge via implicit learning (naïve females). In this way, auditory cortical activation discriminates between instinctive (mothers) and learned (naïve females) cognition.

  20. Earth Observing System/Advanced Microwave SoundingUnit-A (EOS/AMSU-A): Acquisition activities plan

    NASA Technical Reports Server (NTRS)

    Schwantje, Robert

    1994-01-01

    This is the acquisition activities plan for the software to be used in the Earth Observing System (EOS) Advanced Microwave Sounding Unit-A (AMSU-A) system. This document is submitted in response to Contract NAS5-323 14 as CDRL 508. The procurement activities required to acquire software for the EOS/AMSU-A program are defined.

  1. It's More Fun than It Sounds--Enhancing Science Concepts through Hands-on Activities for Young Children

    ERIC Educational Resources Information Center

    Guha, Smita

    2012-01-01

    To teach young children, teachers choose topics in science that children are curious about. Children's inquisitive nature is reflected through the activities as they make repetitive sounds to find the cause and effect relationship. Teachers can make best use of those invaluable moments by incorporating those activities into science lessons on…

  2. Acquired Apraxia of Speech: The Effects of Repeated Practice and Rate/Rhythm Control Treatments on Sound Production Accuracy

    ERIC Educational Resources Information Center

    Wambaugh, Julie L.; Nessler, Christina; Cameron, Rosalea; Mauszycki, Shannon C.

    2012-01-01

    Purpose: This investigation was designed to elucidate the effects of repeated practice treatment on sound production accuracy in individuals with apraxia of speech (AOS) and aphasia. A secondary purpose was to determine if the addition of rate/rhythm control to treatment provided further benefits beyond those achieved with repeated practice.…

  3. Brain Activity Evaluation Using Oxy-Hb by Difference in the Strength of Sound Stimulus

    NASA Astrophysics Data System (ADS)

    Osawa, Takeru; Asano, Hirotoshi; Ide, Hideto

    We carried out a psychological study involving physiological measurements. We used the VAS to research the feeling. The physiological factor measured was the oxy-Hb. It was found that an auditory stimulus of 70[dB] is more uncomfortable than auditory stimulus of 50[dB]. Furthermore, the decrease in oxy-Hb was greater for the auditory stimulus of 70[dB] as compared to the auditory stimulus of 50[dB]. This tendency was found in the center of the forehead (ch22-ch25). There was a difference between the brain activity for the auditory stimulus of 70[dB] and that for the auditory stimulus of 50[dB]. It was also found that the sound level affects the comfort level of humans. It is necessary to obtain additional details on the effects from physiological index to psychological index in a future study.

  4. The Production and Perception of Emotionally Expressive Walking Sounds: Similarities between Musical Performance and Everyday Motor Activity

    PubMed Central

    Giordano, Bruno L.; Egermann, Hauke; Bresin, Roberto

    2014-01-01

    Several studies have investigated the encoding and perception of emotional expressivity in music performance. A relevant question concerns how the ability to communicate emotions in music performance is acquired. In accordance with recent theories on the embodiment of emotion, we suggest here that both the expression and recognition of emotion in music might at least in part rely on knowledge about the sounds of expressive body movements. We test this hypothesis by drawing parallels between musical expression of emotions and expression of emotions in sounds associated with a non-musical motor activity: walking. In a combined production-perception design, two experiments were conducted, and expressive acoustical features were compared across modalities. An initial performance experiment tested for similar feature use in walking sounds and music performance, and revealed that strong similarities exist. Features related to sound intensity, tempo and tempo regularity were identified as been used similarly in both domains. Participants in a subsequent perception experiment were able to recognize both non-emotional and emotional properties of the sound-generating walkers. An analysis of the acoustical correlates of behavioral data revealed that variations in sound intensity, tempo, and tempo regularity were likely used to recognize expressed emotions. Taken together, these results lend support the motor origin hypothesis for the musical expression of emotions. PMID:25551392

  5. Radiometric sounding system

    SciTech Connect

    Whiteman, C.D.; Anderson, G.A.; Alzheimer, J.M.; Shaw, W.J.

    1995-04-01

    Vertical profiles of solar and terrestrial radiative fluxes are key research needs for global climate change research. These fluxes are expected to change as radiatively active trace gases are emitted to the earth`s atmosphere as a consequence of energy production and industrial and other human activities. Models suggest that changes in the concentration of such gases will lead to radiative flux divergences that will produce global warming of the earth`s atmosphere. Direct measurements of the vertical variation of solar and terrestrial radiative fluxes that lead to these flux divergences have been largely unavailable because of the expense of making such measurements from airplanes. These measurements are needed to improve existing atmospheric radiative transfer models, especially under the cloudy conditions where the models have not been adequately tested. A tethered-balloon-borne Radiometric Sounding System has been developed at Pacific Northwest Laboratory to provide an inexpensive means of making routine vertical soundings of radiative fluxes in the earth`s atmospheric boundary layer to altitudes up to 1500 m above ground level. Such vertical soundings would supplement measurements being made from aircraft and towers. The key technical challenge in the design of the Radiometric Sounding System is to develop a means of keeping the radiometers horizontal while the balloon ascends and descends in a turbulent atmospheric environment. This problem has been addressed by stabilizing a triangular radiometer-carrying platform that is carried on the tetherline of a balloon sounding system. The platform, carried 30 m or more below the balloon to reduce the balloon`s effect on the radiometric measurements, is leveled by two automatic control loops that activate motors, gears and pulleys when the platform is off-level. The sensitivity of the automatic control loops to oscillatory motions of various frequencies and amplitudes can be adjusted using filters.

  6. Rapid frequency control of sonar sounds by the FM bat, Miniopterus fuliginosus, in response to spectral overlap.

    PubMed

    Hase, Kazuma; Miyamoto, Takara; Kobayasi, Kohta I; Hiryu, Shizuko

    2016-07-01

    In the presence of multiple flying conspecifics, echolocating bats avoid jamming by adjusting the spectral and/or temporal features of their vocalizations. However, little is known about how bats alter their pulse acoustic characteristics to adapt to an acoustically jamming situation during flight. We investigated echolocation behavior in a bat (Miniopterus fuliginosus) during free flight under acoustic jamming conditions created by downward FM jamming sounds mimicking bat echolocation sounds. In an experimental chamber, the flying bat was exposed to FM jamming sounds with different terminal frequencies (TFs) from loudspeakers. Echolocation pulses emitted by the flying bat were recorded using a telemetry microphone (Telemike) mounted on the back of the bat. The bats immediately (within 150ms) shifted the TFs of emitted pulses upward when FM jamming sounds were presented. Moreover, the amount of upward TF shift differed depending on the TF ranges of the jamming sounds presented. When the TF range was lower than or overlapped the bat's mean TF, the bat TF shifted significantly upward (by 1-2kHz, Student's t-test, P<0.05), corresponding to 3-5% of the total bandwidth of their emitted pulses. These findings indicate that bats actively avoid overlap of the narrow frequency band around the TF. PMID:27157002

  7. Rapid frequency control of sonar sounds by the FM bat, Miniopterus fuliginosus, in response to spectral overlap.

    PubMed

    Hase, Kazuma; Miyamoto, Takara; Kobayasi, Kohta I; Hiryu, Shizuko

    2016-07-01

    In the presence of multiple flying conspecifics, echolocating bats avoid jamming by adjusting the spectral and/or temporal features of their vocalizations. However, little is known about how bats alter their pulse acoustic characteristics to adapt to an acoustically jamming situation during flight. We investigated echolocation behavior in a bat (Miniopterus fuliginosus) during free flight under acoustic jamming conditions created by downward FM jamming sounds mimicking bat echolocation sounds. In an experimental chamber, the flying bat was exposed to FM jamming sounds with different terminal frequencies (TFs) from loudspeakers. Echolocation pulses emitted by the flying bat were recorded using a telemetry microphone (Telemike) mounted on the back of the bat. The bats immediately (within 150ms) shifted the TFs of emitted pulses upward when FM jamming sounds were presented. Moreover, the amount of upward TF shift differed depending on the TF ranges of the jamming sounds presented. When the TF range was lower than or overlapped the bat's mean TF, the bat TF shifted significantly upward (by 1-2kHz, Student's t-test, P<0.05), corresponding to 3-5% of the total bandwidth of their emitted pulses. These findings indicate that bats actively avoid overlap of the narrow frequency band around the TF.

  8. Developing an active artificial hair cell using nonlinear feedback control

    NASA Astrophysics Data System (ADS)

    Joyce, Bryan S.; Tarazaga, Pablo A.

    2015-09-01

    The hair cells in the mammalian cochlea convert sound-induced vibrations into electrical signals. These cells have inspired a variety of artificial hair cells (AHCs) to serve as biologically inspired sound, fluid flow, and acceleration sensors and could one day replace damaged hair cells in humans. Most of these AHCs rely on passive transduction of stimulus while it is known that the biological cochlea employs active processes to amplify sound-induced vibrations and improve sound detection. In this work, an active AHC mimics the active, nonlinear behavior of the cochlea. The AHC consists of a piezoelectric bimorph beam subjected to a base excitation. A feedback control law is used to reduce the linear damping of the beam and introduce a cubic damping term which gives the AHC the desired nonlinear behavior. Model and experimental results show the AHC amplifies the response due to small base accelerations, has a higher frequency sensitivity than the passive system, and exhibits a compressive nonlinearity like that of the mammalian cochlea. This bio-inspired accelerometer could lead to new sensors with lower thresholds of detection, improved frequency sensitivities, and wider dynamic ranges.

  9. Improving Forecast Skill by Assimilation of Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste

    2009-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of cloud cleared radiances R(sub i). This approach allows for the generation of accurate values of R(sub i) and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel error estimates for R(sub i). These error estimates are used for Quality Control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of Quality Control using the NASA GEOS-5 data assimilation system. Assimilation of Quality Controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done operationally by ECMWF and NCEP. Forecast resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

  10. Broadband radiation modes: Estimation and active control

    NASA Astrophysics Data System (ADS)

    Berkhoff, Arthur P.

    2002-03-01

    In this paper we give a formulation of the most efficiently radiating vibration patterns of a vibrating body, the radiation modes, in the time domain. The radiation modes can be used to arrive at efficient weighting schemes for an array of sensors in order to reduce the controller dimensionality. Because these particular radiation modes are optimum in a broadband sense, they are termed broadband radiation modes. Methods are given to obtain these modes from measured data. The broadband radiation modes are used for the design of an actuator array in a feedback control system to reduce the sound power radiated from a plate. Three methods for the design of the actuator are compared, taking into account the reduction of radiated sound power in the controlled frequency range, but also the possible increase of radiated sound power in the uncontrolled frequency range.

  11. On Quality Control Procedures Being Adopted for TRMM LBA and KWAJEX Soundings Data Sets

    NASA Technical Reports Server (NTRS)

    Roy, B.; Halverson, Jeffrey B.; Starr, David OC. (Technical Monitor)

    2001-01-01

    During NASA's Tropical Rainfall Measuring Mission (TRMM) field campaigns Large Scale Biosphere Atmosphere (LBA) held in Amazonia (Brazil) in the period January- February, 1999, and the Kwajalein Experiment (KWAJEX) held in the Republic of Marshall Islands in the period between August-September, 1999, extensive radiosonde observations (raob) were collected using VIZ and Vaisala sondes which have different response characteristics. In all, 320 raob for LBA and 972 fixed raob for KWAJEX have been obtained and are being processed. Most atmospheric sensible heat source (Q1) and apparent moisture sink (Q2) budget studies are based on sounding data, and the accuracy of the raob is important especially in regions of deep moist convection. A data quality control (QC) project has been initiated at GSFC by the principal investigator (JBH), and this paper addresses some of the quantitative findings for the level I and II QC procedures. Based on these quantitative assessment of sensor (or system) biases associated with each type of sonde, the initial data repair work will be started. Evidence of moisture biases between the two different sondes (VIZ and Vaisala) has been shown earlier by Halverson et al. (2000). Vaisala humidity sensors are found to have a low-level dry bias in the boundary layer, whereas above 600 mb the VIZ sensor tends to register a dryer atmosphere. All raob data were subjected to a limit check based on an algorithm already well tested for the raob data obtained during the Tropical Ocean Global Atmosphere (TOGA-COARE).

  12. The Impact of Anthropogenic Activities on Ecosystems of Long Island Sound, N.Y.

    NASA Astrophysics Data System (ADS)

    Lauture, E.; McHugh, C. M.; Nitsche, F. O.; Kenna, T. C.

    2015-12-01

    Long Island Sound (LIS) is a tide-dominated estuary located along heavily populated regions on the eastern coast of the US. Western LIS has been impacted by heavy metals and is susceptible to hypoxic and anoxic conditions since the 1900's. As part of the Long Island Sound Cable Fund and the National Science Foundation programs, we surveyed the western and central regions of LIS in 2006 and 2013, respectively. From the R/V Hugh Sharp and the R/V Seawolf, we collected high-resolution subbottom profiles, multibeam bathymetry, sediment cores, and grabs in distinct sedimentary environments such as channels, terraces, and river mouths. The goal was to evaluate the impact of anthropogenic activities as they relate to physical processes and populated regions. Along western LIS, total organic carbon (TOC) and heavy metal concentrations are higher from the 1850s to the present, especially along locations of known high organic waste. Pre-industrial concentrations of TOC average 2.22% with maximum values of 4.75%. A similar trend is observed with heavy metals. For example, lead (Pb) increased from background levels of ~10 to 20 ppm to over 200 ppm. Benthic foraminifers seem to be influenced by these trends with changes in ecosystems. The dominant assemblage, Elphidium excavatum clavatum remains dominant with a slight decrease in their abundance during anthropogenic times. From ~1850's to the present Ammonia beccarii becomes more abundant. These shifts in foraminifer species to assemblages that tolerate low oxygen conditions reflect the increasing hypoxic conditions. In central LIS, surface sediments average TOC of 1.34% with highest values of 5.21% near the Housatonic River that drains industrialized portions of Connecticut, and lowest values of 0.073% near the Long Island coastline. Understanding the evolution of hypoxia as well as the sources of heavy metals can lead to important implications for restoration of marine ecosystems.

  13. Inferring Meal Eating Activities in Real World Settings from Ambient Sounds: A Feasibility Study

    PubMed Central

    Thomaz, Edison; Zhang, Cheng; Essa, Irfan; Abowd, Gregory D.

    2015-01-01

    Dietary self-monitoring has been shown to be an effective method for weight-loss, but it remains an onerous task despite recent advances in food journaling systems. Semi-automated food journaling can reduce the effort of logging, but often requires that eating activities be detected automatically. In this work we describe results from a feasibility study conducted in-the-wild where eating activities were inferred from ambient sounds captured with a wrist-mounted device; twenty participants wore the device during one day for an average of 5 hours while performing normal everyday activities. Our system was able to identify meal eating with an F-score of 79.8% in a person-dependent evaluation, and with 86.6% accuracy in a person-independent evaluation. Our approach is intended to be practical, leveraging off-the-shelf devices with audio sensing capabilities in contrast to systems for automated dietary assessment based on specialized sensors. PMID:25859566

  14. The influence of sound generator associated with conventional amplification for tinnitus control: randomized blind clinical trial.

    PubMed

    dos Santos, Gisele Munhoes; Bento, Ricardo Ferreira; de Medeiros, Italo Roberto Torres; Oiticcica, Jeanne; da Silva, Eleonora Csipai; Penteado, Silvio

    2014-07-23

    Hearing aids with an integrated sound generator have been used to enhance the treatment of tinnitus. The main aim of this study was to verify whether the combined use of amplification and sound generator is more effective than conventional amplification alone in reducing tinnitus annoyance by means of the use of a new hearing aid with an integrated sound generator. A total of 49 patients underwent a blind randomized clinical trial. Tinnitus annoyance was measured by Tinnitus Handicap Inventory and numerical scales, and psychoacoustic measures of tinnitus were also performed. The sound generator was set at the lowest intensity capable of providing relief from tinnitus. Results showed that 62.5% of the patients presented a reduction in tinnitus annoyance in the combined fitting group and in the group with amplification alone, 78% showed a reduction. This difference between the groups was not statistically significant.

  15. Functional Brain Activation Differences in School-Age Children with Speech Sound Errors: Speech and Print Processing

    ERIC Educational Resources Information Center

    Preston, Jonathan L.; Felsenfeld, Susan; Frost, Stephen J.; Mencl, W. Einar; Fulbright, Robert K.; Grigorenko, Elena L.; Landi, Nicole; Seki, Ayumi; Pugh, Kenneth R.

    2012-01-01

    Purpose: To examine neural response to spoken and printed language in children with speech sound errors (SSE). Method: Functional magnetic resonance imaging was used to compare processing of auditorily and visually presented words and pseudowords in 17 children with SSE, ages 8;6[years;months] through 10;10, with 17 matched controls. Results: When…

  16. Controls Considerations for Turbine Active Clearance Control

    NASA Technical Reports Server (NTRS)

    Melcher, Kevin J.

    2004-01-01

    This presentation discusses active control of turbine tip clearance from a control systems perspective. It is a subset of charts that were presented at the 2003 meeting of the International Society of Air Breathing Engines which was held August 31 through September 5 in Cleveland, Ohio. The associated reference paper is cited at the end of the presentation. The presentation describes active tip clearance control research being conducted by NASA to improve turbine engine systems. The target application for this effort is commercial aircraft engines. However, it is believed that the technologies developed as part of this research will benefit a broad spectrum of current and future turbomachinery. The first part of the presentation discusses the concept of tip clearance, problems associated with it, and the benefits of controlling it. It lays out a framework for implementing tip clearance controls that enables the implementation to progress from purely analytical to hardware-in-the-loop to fully experimental. And it briefly discusses how the technologies developed will be married to the previously described ACC Test Rig for hardware-in-the-loop demonstrations. The final portion of the presentation, describes one of the key technologies in some detail by presenting equations and results for a functional dynamic model of the tip clearance phenomena. As shown, the model exhibits many of the clearance dynamics found in commercial gas turbine engines. However, initial attempts to validate the model identified limitations that are being addressed to make the model more realistic.

  17. Coronal Radio Sounding Experiments with Mars Express: Scintillation Spectra during Low Solar Activity

    SciTech Connect

    Efimov, A. I.; Lukanina, L. A.; Samoznaev, L. N.; Rudash, V. K.; Chashei, I. V.; Bird, M. K.; Paetzold, M.; Tellmann, S.

    2010-03-25

    Coronal radio sounding observations were carried out with the radio science experiment MaRS on the ESA spacecraft Mars Express during the period from 25 August to 22 October 2004. Differential frequency and log-amplitude fluctuations of the dual-frequency signals were recorded during a period of low solar activity. The data are applicable to low heliographic latitudes, i.e. to slow solar wind. The mean frequency fluctuation and power law index of the frequency fluctuation temporal spectra are determined as a function of heliocentric distance. The radial dependence of the frequency fluctuation spectral index alpha reflects the previously documented flattening of the scintillation power spectra in the solar wind acceleration region. Temporal spectra of S-band and X-band normalized log-amplitude fluctuations were investigated over the range of fluctuation frequencies 0.01 Hzactivity. Ranging measurements are presented and compared with frequency and log-amplitude scintillation data. Evidence for a weak increase in the fractional electron density turbulence level is obtained in the range 10-40 solar radii.

  18. Control of tonal noise from subsonic axial fan. Part 1: reconstruction of aeroacoustic sources from far-field sound pressure

    NASA Astrophysics Data System (ADS)

    Gérard, Anthony; Berry, Alain; Masson, Patrice

    2005-12-01

    An inverse method is investigated to evaluate the unsteady rotating forces (dipole strength distribution) acting by the fan on the fluid from far-field acoustic pressure measurements. A development based on the tonal noise generated by a propeller is used to derive a discretized form of the direct problem. The inversion of this direct problem is ill-posed and requires optimization technique to stabilize the solution for small perturbations in the measured acoustic input data. The reconstruction reveals that the conditioning of the inverse model depends on the aeroacoustic source and far-field sensor locations as well as on the frequency under investigation. Simulations show that an adequate choice of a regularization parameter leads to a satisfactory reconstruction of imposed unsteady rotating forces in the presence of measurement noise, and a correct localization of acoustic "hot spots" on the radiation surface. Preliminary experimental results also show the ability to extrapolate the radiated sound field at blade passage frequency (BPF), and harmonics, from the reconstructed forces. These data are exploited in the second part of this paper to evaluate various active control strategies for tonal fan noise.

  19. fMRI activation in relation to sound intensity and loudness.

    PubMed

    Langers, Dave R M; van Dijk, Pim; Schoenmaker, Esther S; Backes, Walter H

    2007-04-01

    The aim of this fMRI study was to relate cortical fMRI responses to both physical and perceptual sound level characteristics. Besides subjects with normal hearing, subjects with high-frequency sensorineural hearing loss were included, as distortion of loudness perception is a characteristic of such impairment. Cortical responses in both subject groups were analyzed as a function of the physical intensity and the perceived loudness of low and high-frequency stimuli. For the low-frequency stimuli, intensity levels ranged from 0 to 70 dB SL; for the high-frequency stimuli, intensity levels were set such that the corresponding loudness levels matched those of the low-frequency stimuli. Responses were found to increase significantly and predominantly linearly with intensity level and with loudness level. Response saturation at the highest levels was not apparent, but activation exhibited a steep rise between 0 and 10 dB for the low-frequency stimuli. The activation in the subjects with hearing loss increased significantly more strongly with stimulus intensity than that in the normally hearing subjects. This reflects loudness recruitment, characterized by a disproportionate increase in loudness with stimulus intensity. In contrast, the rate of activation increase as a function of loudness level did not differ between both subject groups. This demonstrates that fMRI activation at the level of the auditory cortex is more closely related to the percept of a stimulus (i.e., loudness) rather than to its physical characteristics (i.e., intensity). PMID:17254802

  20. Active control of low-speed turbofan tonal noise

    NASA Astrophysics Data System (ADS)

    Sommerfeldt, Scott D.; Remington, Paul J.

    2003-10-01

    Active noise control has been proposed as a technique for reducing the tonal noise radiated from turbofan engines. The sound field in the duct of a turbofan engine is characterized by acoustic modes, which exhibit both a radial and a circumferential spatial dependence. The dominant circumferential modes are determined by the relationship between the number of rotor and stator blades. Using these concepts, an active noise control system has been developed to measure and minimize the modes in the duct of a turbofan engine. By using multiple source and sensor locations, it has also been shown that it is possible to control multiple radial modes within the engine duct. Some of the issues associated with the design of the control system will be reviewed, and results obtained using the Active Noise Control Fan (ANCF) at NASA Glenn Research Center will be presented. [Work supported by NASA.

  1. Controls on wetland loss during large magnitude storms: a case study in Breton Sound, LA

    NASA Astrophysics Data System (ADS)

    Howes, N. C.; Hughes, Z. J.; Fitzgerald, D.; Georgiou, I. Y.; Kulp, M. A.; Miner, M. D.; Smith, J. M.; Barras, J. A.

    2010-12-01

    In 2005, the storm surge and wave field associated with Hurricanes Katrina and Rita eroded 527 km^2 of wetlands within the Louisiana coastal plain. Low salinity wetlands were preferentially eroded, while higher salinity wetlands remained largely intact and unchanged. Field studies were undertaken in Breton Sound, Louisiana, where both the low and high salinity wetlands experienced very similar hydrodynamic conditions during Hurricane Katrina. This site provides a natural case to study the causes of the observed land loss patterns. We observe geotechnical differences between soil profiles in high and low salinity wetlands, as controlled by vegetation, and which result in differential erosion. Low salinity wetlands contain a weak zone at a depth of ~30 cm below the marsh surface; this coincides with the base of rooting and has shear strengths as low as 500-1450 Pa. High salinity wetlands display deeper rooting, have no identifiable weak zone, and shear strengths exceed 4500 Pa throughout the upper soil profile. Results from a model (STWAVE-ADCIRC) are used to establish the hydrodynamic conditions during Hurricane Katrina (storm surge, wave height, and wave period). We calculate the potential shear stresses exerted by waves, accounting for the interaction between the oscillatory flow and the vegetation. Calculated shear stresses were in the range 425-3600 Pa, values sufficient to cause widespread erosion of the low salinity wetlands, but not the high salinity wetlands, corresponding with the observed patterns of land loss. A conceptual model is developed to illustrate the influence of rooting type and depth on the strength profile of wetlands soils and their susceptibility to erosion during large magnitude storms. These findings have implications for wetland restoration schemes involving freshwater diversions.

  2. Active Control of Noise Using Actuator/Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Lindner, Douglas K.; Winder, Patrice; Kirby, George

    1996-01-01

    Current research in smart structures is directed toward the integration of many actuators and sensors into a material. In this paper we investigate the possibility of using this instrumentation for active noise control from a vibrating structures. Current technology for reducing radiated sound is limited by the instrumentation for the control system. These control systems employ relatively small numbers of sensors and actuators. Hence, these control systems must rely on a model of the structure to estimate and control the global vibrations that contribute to the far field pressure. For complex, realistic structures the development of such a model is a formidable task. The model is a limiting factor in the continuing development of structural acoustics. In this paper we propose to increase the number of actuators and sensors of a smart material to offset the complexity of the model used for control design. The sensor arrays will be used to directly sense the shape of the structure rather than using a model of the structures to indirectly sense the shape of the structure. The actuator array is used to apply distributed forces to the structure, rather than using the structure itself as a load path. A control system for the active cancellation of sound is derived from standard control system methodologies.

  3. Optical control of antibacterial activity

    NASA Astrophysics Data System (ADS)

    Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

    2013-11-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a ‘smart’ antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism.

  4. Seasonal and Solar Cycle Variation of the Martian Ionosphere from Nine Years of MARSIS Active Sounding

    NASA Astrophysics Data System (ADS)

    Morgan, David D.; Withers, Paul; Gurnett, Donald; Nemec, Frantisek

    This past June, we celebrated nine years of continuous operation by MARSIS, the radar sounder on the Mars Express spacecraft, in orbit around Mars since Christmas of 2003. The copious data from this instrument in its Active Ionospheric Sounding mode has been used in numerous scientific endeavors to generate empirical models of the Martian ionosphere. The full ionospheric profiles gleaned from analysis of these data are ideal for this kind of effort. Out of more than 170,000 traces collected, we have selected only about 10%, deemed to be of the best quality, and that can be fit to a Chapman layer function. We now have nine years, or 4-3/4 Mars years, worth of ionospheric traces. In addition to sampling nearly five years of seasonal variation, these nine years of data also represent 80% of a normal solar cycle. Therefore, in this work we shall analyze ionospheric traces with the objective of determining variation of atmospheric and ionospheric parameters such as the neutral atmospheric scale height, ionospheric peak altitude, and ionospheric peak density as they vary with the solar cycle and the change in season.

  5. Actively Controlled Components. Chapter 2

    NASA Technical Reports Server (NTRS)

    Horn, W.; Hiller, S.-J.; Pfoertner, H.; Schadow, K.; Rosenfeld, T.; Garg, S.

    2009-01-01

    Active Control can help to meet future engine requirements by an active improvement of the component characteristics. The concept is based on an intelligent control logic, which senses actual operating conditions and reacts with adequate actuator action. This approach can directly improve engine characteristics as performance, operability, durability and emissions on the one hand. On the other hand active control addresses the design constrains imposed by unsteady phenomena like inlet distortion, compressor surge, combustion instability, flow separations, vibration and noise, which only occur during exceptional operating conditions. The feasibility and effectiveness of active control technologies have been demonstrated in lab-scale tests. This chapter describes a broad range of promising applications for each engine component. Significant efforts in research and development remain to implement these technologies in engine rig and finally production engines and to demonstrate today s engine generation airworthiness, safety, reliability, and durability requirements. Active control applications are in particular limited by the gap between available and advanced sensors and actuators, which allow an operation in the harsh environment in an aero engine. The operating and performance requirements for actuators and sensors are outlined for each of the gas turbine sections from inlet to nozzle.

  6. Demonstration of Active Combustion Control

    NASA Technical Reports Server (NTRS)

    Lovett, Jeffrey A.; Teerlinck, Karen A.; Cohen, Jeffrey M.

    2008-01-01

    The primary objective of this effort was to demonstrate active control of combustion instabilities in a direct-injection gas turbine combustor that accurately simulates engine operating conditions and reproduces an engine-type instability. This report documents the second phase of a two-phase effort. The first phase involved the analysis of an instability observed in a developmental aeroengine and the design of a single-nozzle test rig to replicate that phenomenon. This was successfully completed in 2001 and is documented in the Phase I report. This second phase was directed toward demonstration of active control strategies to mitigate this instability and thereby demonstrate the viability of active control for aircraft engine combustors. This involved development of high-speed actuator technology, testing and analysis of how the actuation system was integrated with the combustion system, control algorithm development, and demonstration testing in the single-nozzle test rig. A 30 percent reduction in the amplitude of the high-frequency (570 Hz) instability was achieved using actuation systems and control algorithms developed within this effort. Even larger reductions were shown with a low-frequency (270 Hz) instability. This represents a unique achievement in the development and practical demonstration of active combustion control systems for gas turbine applications.

  7. Active Flow Control Activities at NASA Langley

    NASA Technical Reports Server (NTRS)

    Anders, Scott G.; Sellers, William L., III; Washburn, Anthony E.

    2004-01-01

    NASA Langley continues to aggressively investigate the potential advantages of active flow control over more traditional aerodynamic techniques. This paper provides an update to a previous paper and describes both the progress in the various research areas and the significant changes in the NASA research programs. The goals of the topics presented are focused on advancing the state of knowledge and understanding of controllable fundamental mechanisms in fluids as well as to address engineering challenges. An organizational view of current research activities at NASA Langley in active flow control as supported by several projects is presented. On-center research as well as NASA Langley funded contracts and grants are discussed at a relatively high level. The products of this research are to be demonstrated either in bench-top experiments, wind-tunnel investigations, or in flight as part of the fundamental NASA R&D program and then transferred to more applied research programs within NASA, DOD, and U.S. industry.

  8. Experimental studies of sound field suppression at discrete frequencies

    NASA Astrophysics Data System (ADS)

    Fiks, I. Sh.; Korotin, P. I.; Potapov, O. A.; Fiks, G. E.

    2016-03-01

    Practical implementation of an active sound control system ensuring sound suppression in outer space is described as applied to sound insulation problems for equipment whose total noise level is mainly due to low-frequency discrete spectral components. The operational principle of the proposed system is based on inverse field generation with respect to the field of the initial source of quasi-monochromatic signals. The inverse field is formed by a set of radiators, which are controlled by the signals of pressure receivers positioned in the near field of the source. Experimental studies carried out with the proposed sound control system demonstrate its efficiency and testify to the stability of its operation.

  9. Active control of payload fairing noise using distributed active vibration absorbers

    NASA Astrophysics Data System (ADS)

    Charpentier, Arnaud; Johnson, Marty E.; Fuller, Chris R.

    2003-04-01

    High sound pressure inside a launch vehicle fairing during lift-off can damage the payload. Interior levels of up to 140 dB between 60 and 250 Hz are mostly due to exhaust plume noise combined with the limited transmission loss of lightweight composite fairings and little acoustic damping in the fairing volume. Past work using passive and hybrid passive/reactive noise control devices has shown that their limitations are mostly due to packaging volume and weight penalty. The objective of this work is to design a lightweight, compact, and low electrical power active noise control system to reduce the fairing interior sound level. Hybrid active/passive actuators such as Smart Foam (Couche and Fuller, Proceedings of Active 1999, Ft. Lauderdale, FL, pp. 609-620) and Distributed Active Vibration Absorbers (Marcotte, Fuller, and Johnson, Proceedings of Active 2002, ISVR, Southampton, England, pp. 535-546) are optimized for fairing noise control. The latter have been used to increase the transmission loss of the fairing. Active noise control test results on a sub-scale, sandwich composite fairing are presented. The global interior acoustic response due to airborne exterior excitation is minimized using an adaptive multiple-input, multiple-output feedforward controller. [Work supported by the Air Force Research Laboratory, Space Vehicles Directorate (AFRL).

  10. Extended Active Disturbance Rejection Controller

    NASA Technical Reports Server (NTRS)

    Gao, Zhiqiang (Inventor); Tian, Gang (Inventor)

    2014-01-01

    Multiple designs, systems, methods and processes for controlling a system or plant using an extended active disturbance rejection control (ADRC) based controller are presented. The extended ADRC controller accepts sensor information from the plant. The sensor information is used in conjunction with an extended state observer in combination with a predictor that estimates and predicts the current state of the plant and a co-joined estimate of the system disturbances and system dynamics. The extended state observer estimates and predictions are used in conjunction with a control law that generates an input to the system based in part on the extended state observer estimates and predictions as well as a desired trajectory for the plant to follow.

  11. Extended Active Disturbance Rejection Controller

    NASA Technical Reports Server (NTRS)

    Gao, Zhiqiang (Inventor); Tian, Gang (Inventor)

    2016-01-01

    Multiple designs, systems, methods and processes for controlling a system or plant using an extended active disturbance rejection control (ADRC) based controller are presented. The extended ADRC controller accepts sensor information from the plant. The sensor information is used in conjunction with an extended state observer in combination with a predictor that estimates and predicts the current state of the plant and a co-joined estimate of the system disturbances and system dynamics. The extended state observer estimates and predictions are used in conjunction with a control law that generates an input to the system based in part on the extended state observer estimates and predictions as well as a desired trajectory for the plant to follow.

  12. Extended active disturbance rejection controller

    NASA Technical Reports Server (NTRS)

    Gao, Zhiqiang (Inventor); Tian, Gang (Inventor)

    2012-01-01

    Multiple designs, systems, methods and processes for controlling a system or plant using an extended active disturbance rejection control (ADRC) based controller are presented. The extended ADRC controller accepts sensor information from the plant. The sensor information is used in conjunction with an extended state observer in combination with a predictor that estimates and predicts the current state of the plant and a co-joined estimate of the system disturbances and system dynamics. The extended state observer estimates and predictions are used in conjunction with a control law that generates an input to the system based in part on the extended state observer estimates and predictions as well as a desired trajectory for the plant to follow.

  13. Numerical Comparison of Active Acoustic and Structural Noise Control in a Stiffened Double Wall Cylinder

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.

    1996-01-01

    The active acoustic and structural noise control characteristics of a double wall cylinder with and without ring stiffeners were numerically evaluated. An exterior monopole was assumed to acoustically excite the outside of the double wall cylinder at an acoustic cavity resonance frequency. Structural modal vibration properties of the inner and outer shells were analyzed by post-processing the results from a finite element analysis. A boundary element approach was used to calculate the acoustic cavity response and the coupled structural-acoustic interaction. In the frequency region of interest, below 500 Hz, all structural resonant modes were found to be acoustically slow and the nonresonant modal response to be dominant. Active sound transmission control was achieved by control forces applied to the inner or outer shell, or acoustic control monopoles placed just outside the inner or outer shell. A least mean square technique was used to minimize the interior sound pressures at the nodes of a data recovery mesh. Results showed that single acoustic control monopoles placed just outside the inner or outer shells resulted in better sound transmission control than six distributed point forces applied to either one of the shells. Adding stiffeners to the double wall structure constrained the modal vibrations of the shells, making the double wall stiffer with associated higher modal frequencies. Active noise control obtained for the stiffened double wall configurations was less than for the unstiffened cylinder. In all cases, the acoustic control monopoles controlled the sound transmission into the interior better than the structural control forces.

  14. Active Control of Fan-Generated Tone Noise

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.

    1995-01-01

    This paper reports on an experiment to control the noise radiated from the inlet of a ducted fan using a time domain active adaptive system. The control ,sound source consists of loudspeakers arranged in a ring around the fan duct. The error sensor location is in the fan duct. The purpose of this experiment is to demonstrate that the in-duct error sensor reduces the mode spillover in the far field, thereby increasing the efficiency of the control system. The control system is found to reduce the blade passage frequency tone significantly in the acoustic far field when the mode orders of the noise source and of the control source are the same, when the dominant wave in the duct is a plane wave. The presence of higher order modes in the duct reduces the noise reduction efficiency, particularly near the mode cut-on where the standing wave component is strong, but the control system converges stably. The control system is stable and converges when the first circumferential mode is generated in the duct. The control system is found to reduce the fan noise in the far field on an arc around the fan inlet by as much as 20 dB with none of the sound amplification associated with mode spillover.

  15. Vocalisation Repertoire of Female Bluefin Gurnard (Chelidonichthys kumu) in Captivity: Sound Structure, Context and Vocal Activity

    PubMed Central

    Radford, Craig A.; Ghazali, Shahriman M.; Montgomery, John C.; Jeffs, Andrew G.

    2016-01-01

    Fish vocalisation is often a major component of underwater soundscapes. Therefore, interpretation of these soundscapes requires an understanding of the vocalisation characteristics of common soniferous fish species. This study of captive female bluefin gurnard, Chelidonichthys kumu, aims to formally characterise their vocalisation sounds and daily pattern of sound production. Four types of sound were produced and characterised, twice as many as previously reported in this species. These sounds fit two aural categories; grunt and growl, the mean peak frequencies for which ranged between 129 to 215 Hz. This species vocalized throughout the 24 hour period at an average rate of (18.5 ± 2.0 sounds fish-1 h-1) with an increase in vocalization rate at dawn and dusk. Competitive feeding did not elevate vocalisation as has been found in other gurnard species. Bluefin gurnard are common in coastal waters of New Zealand, Australia and Japan and, given their vocalization rate, are likely to be significant contributors to ambient underwater soundscape in these areas. PMID:26890124

  16. Vocalisation Repertoire of Female Bluefin Gurnard (Chelidonichthys kumu) in Captivity: Sound Structure, Context and Vocal Activity.

    PubMed

    Radford, Craig A; Ghazali, Shahriman M; Montgomery, John C; Jeffs, Andrew G

    2016-01-01

    Fish vocalisation is often a major component of underwater soundscapes. Therefore, interpretation of these soundscapes requires an understanding of the vocalisation characteristics of common soniferous fish species. This study of captive female bluefin gurnard, Chelidonichthys kumu, aims to formally characterise their vocalisation sounds and daily pattern of sound production. Four types of sound were produced and characterised, twice as many as previously reported in this species. These sounds fit two aural categories; grunt and growl, the mean peak frequencies for which ranged between 129 to 215 Hz. This species vocalized throughout the 24 hour period at an average rate of (18.5 ± 2.0 sounds fish-1 h-1) with an increase in vocalization rate at dawn and dusk. Competitive feeding did not elevate vocalisation as has been found in other gurnard species. Bluefin gurnard are common in coastal waters of New Zealand, Australia and Japan and, given their vocalization rate, are likely to be significant contributors to ambient underwater soundscape in these areas. PMID:26890124

  17. Vocalisation Repertoire of Female Bluefin Gurnard (Chelidonichthys kumu) in Captivity: Sound Structure, Context and Vocal Activity.

    PubMed

    Radford, Craig A; Ghazali, Shahriman M; Montgomery, John C; Jeffs, Andrew G

    2016-01-01

    Fish vocalisation is often a major component of underwater soundscapes. Therefore, interpretation of these soundscapes requires an understanding of the vocalisation characteristics of common soniferous fish species. This study of captive female bluefin gurnard, Chelidonichthys kumu, aims to formally characterise their vocalisation sounds and daily pattern of sound production. Four types of sound were produced and characterised, twice as many as previously reported in this species. These sounds fit two aural categories; grunt and growl, the mean peak frequencies for which ranged between 129 to 215 Hz. This species vocalized throughout the 24 hour period at an average rate of (18.5 ± 2.0 sounds fish-1 h-1) with an increase in vocalization rate at dawn and dusk. Competitive feeding did not elevate vocalisation as has been found in other gurnard species. Bluefin gurnard are common in coastal waters of New Zealand, Australia and Japan and, given their vocalization rate, are likely to be significant contributors to ambient underwater soundscape in these areas.

  18. Dual control active superconductive devices

    DOEpatents

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1993-07-20

    A superconducting active device has dual control inputs and is constructed such that the output of the device is effectively a linear mix of the two input signals. The device is formed of a film of superconducting material on a substrate and has two main conduction channels, each of which includes a weak link region. A first control line extends adjacent to the weak link region in the first channel and a second control line extends adjacent to the weak link region in the second channel. The current flowing from the first channel flows through an internal control line which is also adjacent to the weak link region of the second channel. The weak link regions comprise small links of superconductor, separated by voids, through which the current flows in each channel. Current passed through the control lines causes magnetic flux vortices which propagate across the weak link regions and control the resistance of these regions. The output of the device taken across the input to the main channels and the output of the second main channel and the internal control line will constitute essentially a linear mix of the two input signals imposed on the two control lines. The device is especially suited to microwave applications since it has very low input capacitance, and is well suited to being formed of high temperature superconducting materials since all of the structures may be formed coplanar with one another on a substrate.

  19. Design of the Sound-Warning System based on the Micro- Controller

    NASA Astrophysics Data System (ADS)

    Yanbin, SHI; Jian, GUO; Yanli, SHI

    The design and realization of chip type airborne sound-warning system are introduced. Taking the monolithic integrated circuit P87C52X2FN and voice chip ISD4003-8 M as the core, the hardware principle electric circuit and the main software design mentality has produced. This warning system is been provided with some merits such as the strong function, the high precision, expediently operate and so on.

  20. Auditory learning through active engagement with sound: biological impact of community music lessons in at-risk children.

    PubMed

    Kraus, Nina; Slater, Jessica; Thompson, Elaine C; Hornickel, Jane; Strait, Dana L; Nicol, Trent; White-Schwoch, Travis

    2014-01-01

    The young nervous system is primed for sensory learning, facilitating the acquisition of language and communication skills. Social and linguistic impoverishment can limit these learning opportunities, eventually leading to language-related challenges such as poor reading. Music training offers a promising auditory learning strategy by directing attention to meaningful acoustic elements of the soundscape. In light of evidence that music training improves auditory skills and their neural substrates, there are increasing efforts to enact community-based programs to provide music instruction to at-risk children. Harmony Project is a community foundation that has provided free music instruction to over 1000 children from Los Angeles gang-reduction zones over the past decade. We conducted an independent evaluation of biological effects of participating in Harmony Project by following a cohort of children for 1 year. Here we focus on a comparison between students who actively engaged with sound through instrumental music training vs. students who took music appreciation classes. All children began with an introductory music appreciation class, but midway through the year half of the children transitioned to the instrumental training. After the year of training, the children who actively engaged with sound through instrumental music training had faster and more robust neural processing of speech than the children who stayed in the music appreciation class, observed in neural responses to a speech sound /d/. The neurophysiological measures found to be enhanced in the instrumentally-trained children have been previously linked to reading ability, suggesting a gain in neural processes important for literacy stemming from active auditory learning. Despite intrinsic constraints on our study imposed by a community setting, these findings speak to the potential of active engagement with sound (i.e., music-making) to engender experience-dependent neuroplasticity and may inform the

  1. Auditory learning through active engagement with sound: biological impact of community music lessons in at-risk children

    PubMed Central

    Kraus, Nina; Slater, Jessica; Thompson, Elaine C.; Hornickel, Jane; Strait, Dana L.; Nicol, Trent; White-Schwoch, Travis

    2014-01-01

    The young nervous system is primed for sensory learning, facilitating the acquisition of language and communication skills. Social and linguistic impoverishment can limit these learning opportunities, eventually leading to language-related challenges such as poor reading. Music training offers a promising auditory learning strategy by directing attention to meaningful acoustic elements of the soundscape. In light of evidence that music training improves auditory skills and their neural substrates, there are increasing efforts to enact community-based programs to provide music instruction to at-risk children. Harmony Project is a community foundation that has provided free music instruction to over 1000 children from Los Angeles gang-reduction zones over the past decade. We conducted an independent evaluation of biological effects of participating in Harmony Project by following a cohort of children for 1 year. Here we focus on a comparison between students who actively engaged with sound through instrumental music training vs. students who took music appreciation classes. All children began with an introductory music appreciation class, but midway through the year half of the children transitioned to the instrumental training. After the year of training, the children who actively engaged with sound through instrumental music training had faster and more robust neural processing of speech than the children who stayed in the music appreciation class, observed in neural responses to a speech sound /d/. The neurophysiological measures found to be enhanced in the instrumentally-trained children have been previously linked to reading ability, suggesting a gain in neural processes important for literacy stemming from active auditory learning. Despite intrinsic constraints on our study imposed by a community setting, these findings speak to the potential of active engagement with sound (i.e., music-making) to engender experience-dependent neuroplasticity and may inform the

  2. Auditory learning through active engagement with sound: biological impact of community music lessons in at-risk children.

    PubMed

    Kraus, Nina; Slater, Jessica; Thompson, Elaine C; Hornickel, Jane; Strait, Dana L; Nicol, Trent; White-Schwoch, Travis

    2014-01-01

    The young nervous system is primed for sensory learning, facilitating the acquisition of language and communication skills. Social and linguistic impoverishment can limit these learning opportunities, eventually leading to language-related challenges such as poor reading. Music training offers a promising auditory learning strategy by directing attention to meaningful acoustic elements of the soundscape. In light of evidence that music training improves auditory skills and their neural substrates, there are increasing efforts to enact community-based programs to provide music instruction to at-risk children. Harmony Project is a community foundation that has provided free music instruction to over 1000 children from Los Angeles gang-reduction zones over the past decade. We conducted an independent evaluation of biological effects of participating in Harmony Project by following a cohort of children for 1 year. Here we focus on a comparison between students who actively engaged with sound through instrumental music training vs. students who took music appreciation classes. All children began with an introductory music appreciation class, but midway through the year half of the children transitioned to the instrumental training. After the year of training, the children who actively engaged with sound through instrumental music training had faster and more robust neural processing of speech than the children who stayed in the music appreciation class, observed in neural responses to a speech sound /d/. The neurophysiological measures found to be enhanced in the instrumentally-trained children have been previously linked to reading ability, suggesting a gain in neural processes important for literacy stemming from active auditory learning. Despite intrinsic constraints on our study imposed by a community setting, these findings speak to the potential of active engagement with sound (i.e., music-making) to engender experience-dependent neuroplasticity and may inform the

  3. Quality-Controlled Upper-Air Sounding Dataset for DYNAMO/CINDY/AMIE: Development and Corrections

    SciTech Connect

    Ciesielski, Paul; Yu, Hungjui; Johnson, Richard; Yoneyama, Kunio; Katsumata, Masaki; Long, Charles N.; Wang, Junhong; Loehrer, Scot; Young, Kate; Williams, S.; Brown, William; Braun, John; Van Hove, Terese

    2014-04-01

    The upper-air sounding network for DYNAMO (Dynamics of the Madden-Julian Oscillation or MJO) has provided an unprecedented set of observations for studying the MJO over the Indian Ocean (IO) where coupling of this oscillation with deep convection first occurs. With 72 sounding sites and dropsonde data from 13 aircraft mission, the sonde network covers the tropics from Eastern African to the West Pacific. In total nearly 26,000 sondes were collected from this network during the experiment’s 6-month extended observing period (from October 2011 to March 2012). Slightly more than half of the sondes, collected from 33 sites, are at high vertical resolution. Rigorous post-field phase processing of the sonde data included several levels of quality checks and a variety of corrections which address a number of issues (e.g., daytime dry bias, baseline surface data errors, ship deck-heating effects, artificial dry spikes in slow ascent sondes). Because of the importance of an accurate description of the moisture field in meeting the scientific goals of the experiments, particular attention is given to humidity correction and its validation. The humidity corrections, though small relative to some previous field campaigns, produced high fidelity moisture analyses in which sonde precipitable water compared well with independent estimates. An assessment of model operational analyses moisture using corrected sonde data shows an overall good agreement with the exception at upper-levels where model moisture and clouds are more abundant than the sounding data would indicate.

  4. Bone speed of sound and physical activity levels of overweight and normal-weight girls and adolescents.

    PubMed

    Yao, Mathew; Ludwa, Izabella; Corbett, Lauren; Klentrou, Panagiota; Bonsu, Peter; Gammage, Kimberley; Falk, Bareket

    2011-02-01

    Bone properties, reflected by speed of sound (SOS), and physical activity levels were examined in overweight (OW) girls (n = 19) and adolescents (n = 22), in comparison with normal-weight (NW) girls (n = 21) and adolescents (n = 13). Moderate-to-vigorous physical activity (MVPA) was higher in NW than in OW in both age groups. Tibial SOS was lower in OW compared with NW in both age groups. MVPA correlated with tibial SOS, once age was partialed out. The results suggest that overweight girls and adolescents are characterized by low tibial SOS, which may be partially attributed to lower physical activity levels.

  5. Experiment in feedforward control for the reduction of sound transmission through an elastic plate backed by a rigid rectangular cavity

    NASA Astrophysics Data System (ADS)

    Ellis, Graham K.; Koshigoe, Shozo

    1994-05-01

    The payload compartment of space launch vehicles is an acoustically severe environment with sound pressure levels that often exceed 130 dB. Many of the design constraints for satellites are driven by the launch loads and any reduction in these loads would allow lighter spacecraft and significant cost savings because of reduced launch weight and testing requirements. In order to determine the levels of sound attenuation possible in such an application, a simple experimental apparatus consisting of a flexible plate backed by a rigid rectangular cavity has been built to mimic the behavior of a launch vehicle payload compartment. An external speaker is used to simulate the pressure loading caused by vehicle exhaust and turbulent flow around the launch vehicle. This paper provides a comparison of the harmonic disturbance attenuation capability and transient/convergence performance of a fixed analog feedforward and a filtered-x LMS adaptive feedforward controller for the cavity backed plate problem using piezoelectric ceramic actuators on the flexible plate and polyvinylidene fluoride pressure and plate vibration sensors. Controllers are developed for the first plate controlled mode and the first cavity controlled mode.

  6. Teacher's Guide for SST..T..T (Sound, Sense, Today, Tomorrow, Thereafter).

    ERIC Educational Resources Information Center

    Federal Aviation Administration (DOT), Washington, DC.

    Offered in this teacher's guide are activity suggestions, research ideas, discussion questions, and problems to solve dealing with aviation education. Topical areas consider sound and the environment, changes and adjustments in sounds, planning and control of noise, communications, economics, and mathematical and scientific aspects of sound and…

  7. Novel Active Combustion Control Valve

    NASA Technical Reports Server (NTRS)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  8. Active controls for ride smoothing

    NASA Technical Reports Server (NTRS)

    Conner, D. W.; Thompson, G. O.

    1976-01-01

    Active controls technology offers great promise for significantly smoothing the ride, and thus improving public and air carrier acceptance, of certain types of transport aircraft. Recent findings which support this promise are presented in the following three pertinent areas: (1) Ride quality versus degree of traveler satisfaction; (2) significant findings from a feasibility study of a ride smoothing system; and (3) potential ride problems identified for several advanced transport concepts.

  9. Control of Toxic Chemicals in Puget Sound, Phase 3: Study of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound

    SciTech Connect

    Brandenberger, Jill M.; Louchouarn, Patrick; Kuo, Li-Jung; Crecelius, Eric A.; Cullinan, Valerie I.; Gill, Gary A.; Garland, Charity R.; Williamson, J. B.; Dhammapala, R.

    2010-07-05

    The results of the Phase 1 Toxics Loading study suggested that runoff from the land surface and atmospheric deposition directly to marine waters have resulted in considerable loads of contaminants to Puget Sound (Hart Crowser et al. 2007). The limited data available for atmospheric deposition fluxes throughout Puget Sound was recognized as a significant data gap. Therefore, this study provided more recent or first reported atmospheric deposition fluxes of PAHs, PBDEs, and select trace elements for Puget Sound. Samples representing bulk atmospheric deposition were collected during 2008 and 2009 at seven stations around Puget Sound spanning from Padilla Bay south to Nisqually River including Hood Canal and the Straits of Juan de Fuca. Revised annual loading estimates for atmospheric deposition to the waters of Puget Sound were calculated for each of the toxics and demonstrated an overall decrease in the atmospheric loading estimates except for polybrominated diphenyl ethers (PBDEs) and total mercury (THg). The median atmospheric deposition flux of total PBDE (7.0 ng/m2/d) was higher than that of the Hart Crowser (2007) Phase 1 estimate (2.0 ng/m2/d). The THg was not significantly different from the original estimates. The median atmospheric deposition flux for pyrogenic PAHs (34.2 ng/m2/d; without TCB) shows a relatively narrow range across all stations (interquartile range: 21.2- 61.1 ng/m2/d) and shows no influence of season. The highest median fluxes for all parameters were measured at the industrial location in Tacoma and the lowest were recorded at the rural sites in Hood Canal and Sequim Bay. Finally, a semi-quantitative apportionment study permitted a first-order characterization of source inputs to the atmosphere of the Puget Sound. Both biomarker ratios and a principal component analysis confirmed regional data from the Puget Sound and Straits of Georgia region and pointed to the predominance of biomass and fossil fuel (mostly liquid petroleum products such

  10. Exploring Noise: Sound Pollution.

    ERIC Educational Resources Information Center

    Rillo, Thomas J.

    1979-01-01

    The second part of a three-part series, this article describes sound measurement, effects, and indoor learning activities. Thirty elementary school activities are described with appropriate grade levels specified. (Author/CS)

  11. Active Control of Panel Vibrations Induced by a Boundary Layer Flow

    NASA Technical Reports Server (NTRS)

    Chow, Pao-Liu

    1998-01-01

    In recent years, active and passive control of sound and vibration in aeroelastic structures have received a great deal of attention due to many potential applications to aerospace and other industries. There exists a great deal of research work done in this area. Recent advances in the control of sound and vibration can be found in the several conference proceedings. In this report we will summarize our research findings supported by the NASA grant NAG-1-1175. The problems of active and passive control of sound and vibration has been investigated by many researchers for a number of years. However, few of the articles are concerned with the sound and vibration with flow-structure interaction. Experimental and numerical studies on the coupling between panel vibration and acoustic radiation due to flow excitation have been done by Maestrello and his associates at NASA/Langley Research Center. Since the coupled system of nonlinear partial differential equations is formidable, an analytical solution to the full problem seems impossible. For this reason, we have to simplify the problem to that of the nonlinear panel vibration induced by a uniform flow or a boundary-layer flow with a given wall pressure distribution. Based on this simplified model, we have been able to study the control and stabilization of the nonlinear panel vibration, which have not been treated satisfactorily by other authors. The vibration suppression will clearly reduce the sound radiation power from the panel. The major research findings will be presented in the next three sections. In Section II we shall describe our results on the boundary control of nonlinear panel vibration, with or without flow excitation. Section III is concerned with active control of the vibration and sound radiation from a nonlinear elastic panel. A detailed description of our work on the parametric vibrational control of nonlinear elastic panel will be presented in Section IV. This paper will be submitted to the Journal

  12. Improved Temperature Sounding and Quality Control Methodology Using AIRS/AMSU Data: The AIRS Science Team Version 5 Retrieval Algorithm

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Blaisdell, John M.; Iredell, Lena; Keita, Fricky

    2009-01-01

    This paper describes the AIRS Science Team Version 5 retrieval algorithm in terms of its three most significant improvements over the methodology used in the AIRS Science Team Version 4 retrieval algorithm. Improved physics in Version 5 allows for use of AIRS clear column radiances in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of clear column radiances .R(sub i) for all channels. This new approach allows for the generation of more accurate values of .R(sub i) and T(p) under most cloud conditions. Secondly, Version 5 contains a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 also contains for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology, referred to as AIRS Version 5 AO, was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Results are shown comparing the relative performance of the AIRS Version 4, Version 5, and Version 5 AO for the single day, January 25, 2003. The Goddard DISC is now generating and distributing products derived using the AIRS Science Team Version 5 retrieval algorithm. This paper also described the Quality Control flags contained in the DISC AIRS/AMSU retrieval products and their intended use for scientific research purposes.

  13. Active Noise Control of Radiated Noise from Jets Originating NASA

    NASA Technical Reports Server (NTRS)

    Doty, Michael J.; Fuller, Christopher R.; Schiller, Noah H.; Turner, Travis L.

    2013-01-01

    The reduction of jet noise using a closed-loop active noise control system with highbandwidth active chevrons was investigated. The high frequency energy introduced by piezoelectrically-driven chevrons was demonstrated to achieve a broadband reduction of jet noise, presumably due to the suppression of large-scale turbulence. For a nozzle with one active chevron, benefits of up to 0.8 dB overall sound pressure level (OASPL) were observed compared to a static chevron nozzle near the maximum noise emission angle, and benefits of up to 1.9 dB OASPL were observed compared to a baseline nozzle with no chevrons. The closed-loop actuation system was able to effectively reduce noise at select frequencies by 1-3 dB. However, integrated OASPL did not indicate further reduction beyond the open-loop benefits, most likely due to the preliminary controller design, which was focused on narrowband performance.

  14. Neuronal activity controls transsynaptic geometry

    PubMed Central

    Glebov, Oleg O.; Cox, Susan; Humphreys, Lawrence; Burrone, Juan

    2016-01-01

    The neuronal synapse is comprised of several distinct zones, including presynaptic vesicle zone (SVZ), active zone (AZ) and postsynaptic density (PSD). While correct relative positioning of these zones is believed to be essential for synaptic function, the mechanisms controlling their mutual localization remain unexplored. Here, we employ high-throughput quantitative confocal imaging, super-resolution and electron microscopy to visualize organization of synaptic subdomains in hippocampal neurons. Silencing of neuronal activity leads to reversible reorganization of the synaptic geometry, resulting in a increased overlap between immunostained AZ and PSD markers; in contrast, the SVZ-AZ spatial coupling is decreased. Bayesian blinking and bleaching (3B) reconstruction reveals that the distance between the AZ-PSD distance is decreased by 30 nm, while electron microscopy shows that the width of the synaptic cleft is decreased by 1.1 nm. Our findings show that multiple aspects of synaptic geometry are dynamically controlled by neuronal activity and suggest mutual repositioning of synaptic components as a potential novel mechanism contributing to the homeostatic forms of synaptic plasticity. PMID:26951792

  15. Active load control using microtabs

    NASA Astrophysics Data System (ADS)

    Yen, Dora Te-Lun

    2001-11-01

    Micro-electro-mechanical (MEM) translational tabs are introduced for enhancing and controlling the aerodynamic loading on lifting surfaces. These microtabs are mounted near the trailing edge of lifting surfaces, retract and extend approximately normal to the surface and have a maximum deployment height on the order of the boundary-layer thickness. Deployment of the device effectively modifies the camber distribution of the lifting surface and hence, the lift generated. The effect of the microtabs on lift is shown to be as powerful as conventional control surfaces with lift changes of 30%--50% in the linear range of the lift curve using a tab with a height of 1% of airfoil chord placed at 5% of chord upstream of the trailing edge on the lower surface. A multi-disciplinary approach incorporating aspects of experimental and computational aerodynamics, mechanical design and microfabrication techniques has been taken to develop and test a "proof of concept" model. Flow simulations, using a Reynolds-averaged Navier Stokes solver, have been conducted to optimize the size and placement of the devices based on trailing edge volume constraints. Numerical and experimental wind tunnel results are in good agreement, and both confirm that these micro-scale devices create macro-scale changes in aerodynamic loading. Application of this rather simple but innovative lift control system based on microfabrication techniques introduces a robust, dynamic control device and will allow for the miniaturization of conventional high lift and control systems. The result is a significant reduction in typical control system weight, complexity and cost. Also due to the minute size of these tabs, their activation and response times are much faster than that of conventional trailing edge devices. The "proof of concept" tab design, fabrication techniques, computational and experimental setup, and test results using a representative airfoil are presented in this research. (For more information, see

  16. Active Shielding and Control of Environmental Noise

    NASA Technical Reports Server (NTRS)

    Tsynkov, S. V.

    2001-01-01

    In the framework of the research project supported by NASA under grant # NAG-1-01064, we have studied the mathematical aspects of the problem of active control of sound, i.e., time-harmonic acoustic disturbances. The foundations of the methodology are described in our paper [1]. Unlike. many other existing techniques, the approach of [1] provides for the exact volumetric cancellation of the unwanted noise on a given predetermined region airspace, while leaving unaltered those components of the total acoustic field that are deemed as friendly. The key finding of the work is that for eliminating the unwanted component of the acoustic field in a given area, one needs to know relatively little; in particular, neither the locations nor structure nor strength of the exterior noise sources need to be known. Likewise, there is no need to know the volumetric properties of the supporting medium across which the acoustic signals propagate, except, maybe, in a narrow area of space near the perimeter of the protected region. The controls are built based solely on the measurements performed on the perimeter of the domain to be shielded; moreover, the controls themselves (i.e., additional sources) are concentrated also only on or near this perimeter. Perhaps as important, the measured quantities can refer to the total acoustic field rather than to its unwanted component only, and the methodology can automatically distinguish between the two. In [1], we have constructed the general solution for controls. The apparatus used for deriving this general solution is closely connected to the concepts of generalized potentials and boundary projections of Calderon's type. For a given total wave field, the application of a Calderon's projection allows one to definitively tell between its incoming and outgoing components with respect to a particular domain of interest, which may have arbitrary shape. Then, the controls are designed so that they suppress the incoming component for the domain

  17. Modeling the Transmission of Sound.

    ERIC Educational Resources Information Center

    Palmer, David H.

    2003-01-01

    Introduces a functional model of sound transmission through solids and gases. Describes procedures of an activity to model how sound travels faster through solid materials than gases. Use dominoes to represent the particles of solids and gases. (KHR)

  18. Exploring Noise: Sound Pollution.

    ERIC Educational Resources Information Center

    Rillo, Thomas J.

    1979-01-01

    Part one of a three-part series about noise pollution and its effects on humans. This section presents the background information for teachers who are preparing a unit on sound. The next issues will offer learning activities for measuring the effects of sound and some references. (SA)

  19. Parallel pathways mediating both sound localization and gaze control in the forebrain and midbrain of the barn owl.

    PubMed

    Knudsen, E I; Knudsen, P F; Masino, T

    1993-07-01

    The hypothesis that sound localization and gaze control are mediated in parallel in the midbrain and forebrain was tested in the barn owl. The midbrain pathway for gaze control was interrupted by reversible inactivation (muscimol injection) or lesion of the optic tectum. Auditory input to the forebrain was disrupted by reversible inactivation or lesion of the primary thalamic auditory nucleus, nucleus ovoidalis (homolog of the medial geniculate nucleus). Barn owls were trained to orient their gaze toward auditory or visual stimuli presented from random locations in a darkened sound chamber. Auditory and visual test stimuli were brief so that the stimulus was over before the orienting response was completed. The accuracy and kinetics of the orienting responses were measured with a search coil attached to the head. Unilateral inactivation of the optic tectum had immediate and long-lasting effects on auditory orienting behavior. The owls failed to respond on a high percentage of trials when the auditory test stimulus was located on the side contralateral to the inactivated tectum. When they did respond, the response was usually (but not always) short of the target, and the latency of the response was abnormally long. When the auditory stimulus was located on the side ipsilateral to the inactivated tectum, responses were reliable and accurate, and the latency of responses was shorter than normal. In a tectally lesioned animal, response probability and latency to contralateral sounds returned to normal within 2 weeks, but the increase in response error (due to undershooting) persisted for at least 12 weeks. Despite abnormalities in the response, all of the owls were capable of localizing and orienting to contralateral auditory stimuli on some trials with the optic tectum inactivated or lesioned. This was not true for contralateral visual stimuli. Immediately following tectal inactivation, the owls exhibited complete neglect for visual stimuli located more than 20

  20. Estuarine and coastal water dynamics controlling sediment movement and plume development in Long Island Sound

    NASA Technical Reports Server (NTRS)

    Ruggles, F. H., Jr. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. As the Connecticut River flows into Long Island Sound, large plumes develop during the mixing of ocean and estuarine waters. Plumes were delineated for July 28, October 8, October 27, and December 2, 1972, by analyzing ERTS-1 imagery with the SRI Electronic Satellite Image Analysis Console (ESIAC). Because the chemical and physical composition of the plume and ocean water were not too different, the ESIAC was utilized to expand the scenes and subject the transparencies to varying combinations of viewing techniques to identify and delineate the plumes. Best results were obtained when band 5 transparencies were used. Indications are, when the scene being analyzed is predominantly in the first two steps of the gray scale, it is best to use the negative transparencies. When the analysis is being done above the first two steps of the gray scale, it is best to use the positive transparencies.

  1. Active vibration and noise control of vibro-acoustic system by using PID controller

    NASA Astrophysics Data System (ADS)

    Li, Yunlong; Wang, Xiaojun; Huang, Ren; Qiu, Zhiping

    2015-07-01

    Active control simulation of the acoustic and vibration response of a vibro-acoustic cavity of an airplane based on a PID controller is presented. A full numerical vibro-acoustic model is developed by using an Eulerian model, which is a coupled model based on the finite element formulation. The reduced order model, which is used to design the closed-loop control system, is obtained by the combination of modal expansion and variable substitution. Some physical experiments are made to validate and update the full-order and the reduced-order numerical models. Optimization of the actuator placement is employed in order to get an effective closed-loop control system. For the controller design, an iterative method is used to determine the optimal parameters of the PID controller. The process is illustrated by the design of an active noise and vibration control system for a cavity structure. The numerical and experimental results show that a PID-based active control system can effectively suppress the noise inside the cavity using a sound pressure signal as the controller input. It is also possible to control the noise by suppressing the vibration of the structure using the structural displacement signal as the controller input. For an airplane cavity structure, considering the issue of space-saving, the latter is more suitable.

  2. Effects of anthropogenic sound on digging behavior, metabolism, Ca2+/Mg2+ ATPase activity, and metabolism-related gene expression of the bivalve Sinonovacula constricta

    PubMed Central

    Peng, Chao; Zhao, Xinguo; Liu, Saixi; Shi, Wei; Han, Yu; Guo, Cheng; Jiang, Jingang; Wan, Haibo; Shen, Tiedong; Liu, Guangxu

    2016-01-01

    Anthropogenic sound has increased significantly in the past decade. However, only a few studies to date have investigated its effects on marine bivalves, with little known about the underlying physiological and molecular mechanisms. In the present study, the effects of different types, frequencies, and intensities of anthropogenic sounds on the digging behavior of razor clams (Sinonovacula constricta) were investigated. The results showed that variations in sound intensity induced deeper digging. Furthermore, anthropogenic sound exposure led to an alteration in the O:N ratios and the expression of ten metabolism-related genes from the glycolysis, fatty acid biosynthesis, tryptophan metabolism, and Tricarboxylic Acid Cycle (TCA cycle) pathways. Expression of all genes under investigation was induced upon exposure to anthropogenic sound at ~80 dB re 1 μPa and repressed at ~100 dB re 1 μPa sound. In addition, the activity of Ca2+/Mg2+-ATPase in the feet tissues, which is directly related to muscular contraction and subsequently to digging behavior, was also found to be affected by anthropogenic sound intensity. The findings suggest that sound may be perceived by bivalves as changes in the water particle motion and lead to the subsequent reactions detected in razor clams. PMID:27063002

  3. Effects of anthropogenic sound on digging behavior, metabolism, Ca2+/Mg2+ ATPase activity, and metabolism-related gene expression of the bivalve Sinonovacula constricta

    NASA Astrophysics Data System (ADS)

    Peng, Chao; Zhao, Xinguo; Liu, Saixi; Shi, Wei; Han, Yu; Guo, Cheng; Jiang, Jingang; Wan, Haibo; Shen, Tiedong; Liu, Guangxu

    2016-04-01

    Anthropogenic sound has increased significantly in the past decade. However, only a few studies to date have investigated its effects on marine bivalves, with little known about the underlying physiological and molecular mechanisms. In the present study, the effects of different types, frequencies, and intensities of anthropogenic sounds on the digging behavior of razor clams (Sinonovacula constricta) were investigated. The results showed that variations in sound intensity induced deeper digging. Furthermore, anthropogenic sound exposure led to an alteration in the O:N ratios and the expression of ten metabolism-related genes from the glycolysis, fatty acid biosynthesis, tryptophan metabolism, and Tricarboxylic Acid Cycle (TCA cycle) pathways. Expression of all genes under investigation was induced upon exposure to anthropogenic sound at ~80 dB re 1 μPa and repressed at ~100 dB re 1 μPa sound. In addition, the activity of Ca2+/Mg2+-ATPase in the feet tissues, which is directly related to muscular contraction and subsequently to digging behavior, was also found to be affected by anthropogenic sound intensity. The findings suggest that sound may be perceived by bivalves as changes in the water particle motion and lead to the subsequent reactions detected in razor clams.

  4. Physiographic and land cover attributes of the Puget Lowland and the active streamflow gaging network, Puget Sound Basin

    USGS Publications Warehouse

    Konrad, Christopher; Sevier, Maria

    2014-01-01

    Geospatial information for the active streamflow gaging network in the Puget Sound Basin was compiled to support regional monitoring of stormwater effects to small streams. The compilation includes drainage area boundaries and physiographic and land use attributes that affect hydrologic processes. Three types of boundaries were used to tabulate attributes: Puget Sound Watershed Characterization analysis units (AU); the drainage area of active streamflow gages; and the catchments of Regional Stream Monitoring Program (RSMP) sites. The active streamflow gaging network generally includes sites that represent the ranges of attributes for lowland AUs, although there are few sites with low elevations (less than 60 meters), low precipitation (less than 1 meter year), or high stream density (greater than 5 kilometers per square kilometers). The active streamflow gaging network can serve to provide streamflow information in some AUs and RSMP sites, particularly where the streamflow gage measures streamflow generated from a part of the AU or that drains to the RSMP site, and that part of the AU or RSMP site is a significant fraction of the drainage area of the streamgage. The maximum fraction of each AU or RSMP catchment upstream of a streamflow gage and the maximum fraction of any one gaged basin in an AU or RSMP along with corresponding codes are provided in the attribute tables.

  5. Active control of counter-rotating open rotor interior noise in a Dornier 728 experimental aircraft

    NASA Astrophysics Data System (ADS)

    Haase, Thomas; Unruh, Oliver; Algermissen, Stephan; Pohl, Martin

    2016-08-01

    The fuel consumption of future civil aircraft needs to be reduced because of the CO2 restrictions declared by the European Union. A consequent lightweight design and a new engine concept called counter-rotating open rotor are seen as key technologies in the attempt to reach this ambitious goals. Bearing in mind that counter-rotating open rotor engines emit very high sound pressures at low frequencies and that lightweight structures have a poor transmission loss in the lower frequency range, these key technologies raise new questions in regard to acoustic passenger comfort. One of the promising solutions for the reduction of sound pressure levels inside the aircraft cabin are active sound and vibration systems. So far, active concepts have rarely been investigated for a counter-rotating open rotor pressure excitation on complex airframe structures. Hence, the state of the art is augmented by the preliminary study presented in this paper. The study shows how an active vibration control system can influence the sound transmission of counter-rotating open rotor noise through a complex airframe structure into the cabin. Furthermore, open questions on the way towards the realisation of an active control system are addressed. In this phase, an active feedforward control system is investigated in a fully equipped Dornier 728 experimental prototype aircraft. In particular, the sound transmission through the airframe, the coupling of classical actuators (inertial and piezoelectric patch actuators) into the structure and the performance of the active vibration control system with different error sensors are investigated. It can be shown that the active control system achieves a reduction up to 5 dB at several counter-rotating open rotor frequencies but also that a better performance could be achieved through further optimisations.

  6. Active control of fan noise from a turbofan engine

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H.; Burdisso, Ricardo A.; Fuller, Christopher R.; O'Brien, Walter F.

    1994-01-01

    A three-channel active control system is applied to an operational turbofan engine to reduce tonal noise produced by both the fan and the high-pressure compressor. The control approach is the feedforward filtered-x least-mean-square algorithm implemented on a digital signal processing board. Reference transducers mounted on the engine case provide blade passing and harmonics frequency information to the controller. Error information is provided by large area microphones placed in the acoustic far field. To minimize the error signal, the controller actuates loudspeakers mounted on the inlet to produce destructive interference. The sound pressure level of the fundamental tone of the fan was reduced using the three-channel controller by up to 16 dB over a +/- 30-deg angle about the engine axis. A single-channel controller could produce reduction over a +/- 15-deg angle. The experimental results show the control to be robust. Outside of the areas contolled, the levels of the tone actually increased due to the generation of radial modes by the control sources. Simultaneous control of two tones is achieved with parallel controllers. The fundamental and the first harmonic tones of the fan were controlled simultaneously with reductions of 12 and 5 dBA, respectively, measured on the engine axis. Simultaneous control was also demonstrated for the fan fundamental and the high-pressure compressor fundamental tones.

  7. Cortical regions activated by the subjective sense of perceptual coherence of environmental sounds: a proposal for a neuroscience of intuition.

    PubMed

    Volz, Kirsten G; Rübsamen, Rudolf; von Cramon, D Yves

    2008-09-01

    According to the Oxford English Dictionary, intuition is "the ability to understand or know something immediately, without conscious reasoning." In other words, people continuously, without conscious attention, recognize patterns in the stream of sensations that impinge upon them. The result is a vague perception of coherence, which subsequently biases thought and behavior accordingly. Within the visual domain, research using paradigms with difficult recognition has suggested that the orbitofrontal cortex (OFC) serves as a fast detector and predictor of potential content that utilizes coarse facets of the input. To investigate whether the OFC is crucial in biasing task-specific processing, and hence subserves intuitive judgments in various modalities, we used a difficult-recognition paradigm in the auditory domain. Participants were presented with short sequences of distorted, nonverbal, environmental sounds and had to perform a sound categorization task. Imaging results revealed rostral medial OFC activation for such auditory intuitive coherence judgments. By means of a conjunction analysis between the present results and those from a previous study on visual intuitive coherence judgments, the rostral medial OFC was shown to be activated via both modalities. We conclude that rostral OFC activation during intuitive coherence judgments subserves the detection of potential content on the basis of only coarse facets of the input. PMID:18814468

  8. Cortical regions activated by the subjective sense of perceptual coherence of environmental sounds: a proposal for a neuroscience of intuition.

    PubMed

    Volz, Kirsten G; Rübsamen, Rudolf; von Cramon, D Yves

    2008-09-01

    According to the Oxford English Dictionary, intuition is "the ability to understand or know something immediately, without conscious reasoning." In other words, people continuously, without conscious attention, recognize patterns in the stream of sensations that impinge upon them. The result is a vague perception of coherence, which subsequently biases thought and behavior accordingly. Within the visual domain, research using paradigms with difficult recognition has suggested that the orbitofrontal cortex (OFC) serves as a fast detector and predictor of potential content that utilizes coarse facets of the input. To investigate whether the OFC is crucial in biasing task-specific processing, and hence subserves intuitive judgments in various modalities, we used a difficult-recognition paradigm in the auditory domain. Participants were presented with short sequences of distorted, nonverbal, environmental sounds and had to perform a sound categorization task. Imaging results revealed rostral medial OFC activation for such auditory intuitive coherence judgments. By means of a conjunction analysis between the present results and those from a previous study on visual intuitive coherence judgments, the rostral medial OFC was shown to be activated via both modalities. We conclude that rostral OFC activation during intuitive coherence judgments subserves the detection of potential content on the basis of only coarse facets of the input.

  9. Active control of fan noise from a turbofan engine

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H.; Burdisso, Ricardo A.; Fuller, Christopher R.; O'Brien, Walter F.

    1993-01-01

    A three channel active control system is applied to an operational turbofan engine in order to reduce tonal noise produced by both the fan and high pressure compressor. The control approach is the feedforward filtered-x least-mean-square algorithm implemented on a digital signal processing board. Reference transducers mounted on the engine case provides blade passing and harmonics frequency information to the controller. Error information is provided by large area microphones placed in the acoustic far field. In order to minimize the error signal, the controller actuates loudspeakers mounted on the inlet to produce destructive interference. The sound pressure level of the fundamental tone of the fan was reduced using the three channel controller by up to 16 dB over a 60 deg angle about the engine axis. A single channel controller could produce reduction over a 30 deg angle. The experimental results show the control to be robust. Simultaneous control of two tones is done with parallel controllers. The fundamental and the first harmonic tones of the fan were controlled simultaneously with reductions of 12 dBA and 5 dBA, respectively, measured on the engine axis. Simultaneous control was also demonstrated for the fan fundamental and the high pressure compressor fundamental tones.

  10. Geologic controls on the recent evolution of oyster reefs in Apalachicola Bay and St. George Sound, Florida

    NASA Astrophysics Data System (ADS)

    Twichell, D.; Edmiston, L.; Andrews, B.; Stevenson, W.; Donoghue, J.; Poore, R.; Osterman, L.

    2010-07-01

    Apalachicola Bay and St. George Sound contain the largest oyster fishery in Florida, and the growth and distribution of the numerous oyster reefs here are the combined product of modern estuarine conditions in the bay and its late Holocene evolution. Sidescan-sonar imagery, bathymetry, high-resolution seismic profiles, and sediment cores show that oyster beds occupy the crests of a series of shoals that range from 1 to 7 km in length, trend roughly north-south perpendicular to the long axes of the bay and sound, and are asymmetrical with steeper sides facing to the west. Surface sediment samples show that the oyster beds consist of shelly sand, while much of the remainder of the bay floor is covered by mud delivered by the Apalachicola River. The present oyster reefs rest on sandy delta systems that advanced southward across the region between 6400 and 4400 yr BP when sea level was 4-6 m lower than present. Oysters started to colonize the region around 5100 yr BP and became extensive by 1200 and 2400 yr BP. Since 1200 yr BP, their aerial extent has decreased due to burial of the edges of the reefs by the prodelta mud that continues to be supplied by the Apalachicola River. Oyster reefs that are still active are narrower than the original beds, have grown vertically, and become asymmetrical in cross-section. Their internal bedding indicates they have migrated westward, suggesting a net westerly transport of sediment in the bay.

  11. Active control of noise radiated through rectangular plates using piezeletric patches

    NASA Astrophysics Data System (ADS)

    Santana, Danuza Cristina; Duarte, Marcus Antonio Viana; Rade, Domingos Alves

    2002-11-01

    Due to problems caused by noise in industrial environment and in human daily life, techniques of noise control have received increasing attention from engineers and researchers lately. More recently, the use of piezeletric elements as sensors and/or actuators in noise and vibration control systems has been extensively investigated. The main advantage of the use of such devices is that they can be easily integrated to the mechanical system with little added mass and relatively high control authority. The present paper addresses a technique of active control of sound transmitted through a rectangular, thin, simply supported plate by employing multiple piezeletric patches bonded to the plate's surface. A harmonic plane wave incident on one side of the plate is considered to be the primary noise source. Aiming at minimizing the noise transmitted to the other side of the plate, bending motion is induced through the piezeletric patches so that the plate behaves as a secondary sound source. The paper brings the development of the system mathematical model which enables to obtain the spatial distribution of sound pressure radiated through the plate in the far field. An optimal control technique providing the voltage control signals for the activation of the piezoelectric patches is presented, based on the minimization of a cost function representing the mean square integral of the sound pressure radiated in a semi-sphere in far field. It is also proposed a methodology for the optimal placement on the piezelectric patches using Genetic Algorithms. (To be presented in Portuguese.)

  12. Active Spacecraft Potential Control Investigation

    NASA Astrophysics Data System (ADS)

    Torkar, K.; Nakamura, R.; Tajmar, M.; Scharlemann, C.; Jeszenszky, H.; Laky, G.; Fremuth, G.; Escoubet, C. P.; Svenes, K.

    2016-03-01

    In tenuous plasma the floating potential of sunlit spacecraft reaches tens of volts, positive. The corresponding field disturbs measurements of the ambient plasma by electron and ion sensors and can reduce micro-channel plate lifetime in electron detectors owing to large fluxes of attracted photoelectrons. Also the accuracy of electric field measurements may suffer from a high spacecraft potential. The Active Spacecraft Potential Control (ASPOC) neutralizes the spacecraft potential by releasing positive charge produced by indium ion emitters. The method has been successfully applied on other spacecraft such as Cluster and Double Star. Two ASPOC units are present on each spacecraft. Each unit contains four ion emitters, whereby one emitter per instrument is operated at a time. ASPOC for the Magnetospheric Multiscale (MMS) mission includes new developments in the design of the emitters and the electronics. New features include the use of capillaries instead of needles, new materials for the emitters and their internal thermal insulators, an extended voltage and current range of the electronics, both for ion emission and heating purposes, and a more capable control software. This enables lower spacecraft potentials, higher reliability, and a more uniform potential structure in the spacecraft's sheath compared to previous missions. Results from on-ground testing demonstrate compliance with requirements. Model calculations confirm the findings from previous applications that the plasma measurements will not be affected by the beam's space charge. Finally, the various operating modes to adapt to changing boundary conditions are described along with the main data products.

  13. Sounds Alive: A Noise Workbook.

    ERIC Educational Resources Information Center

    Dickman, Donna McCord

    Sarah Screech, Danny Decibel, Sweetie Sound and Neil Noisy describe their experiences in the world of sound and noise to elementary students. Presented are their reports, games and charts which address sound measurement, the effects of noise on people, methods of noise control, and related areas. The workbook is intended to stimulate students'…

  14. National Report Germany: Sounding Rocket and Balloon Research Activities Supported by the German Space Programme in 2013-2015

    NASA Astrophysics Data System (ADS)

    Kuhl, R.; Gritzner, C.; Friedrichs, D.

    2015-09-01

    Mainly sounding rockets but also stratospheric balloons have played a crucial role in implementing the German Space Programme since many years. Research activities were conducted in the fields of Microgravity Research, Space Science, Earth Observation, Space Technology Development, and Education. Currently, the mesosphere and ionosphere of the Earth and the photosphere and chromosphere of the Sun are in the focus of German research activities in the field of Space Science. Microgravity related topics are studied in the disciplines of Life and Physical Sciences during ballistic TEXUS and MAPHEUS rocket flights. A lot of student activities are currently supported by the agencies SNSB and DLR under the auspices of the Swedish-German programme REXUS/BEXUS.

  15. The Sound of Silence: Activating Silent Biosynthetic Gene Clusters in Marine Microorganisms

    PubMed Central

    Reen, F. Jerry; Romano, Stefano; Dobson, Alan D.W.; O’Gara, Fergal

    2015-01-01

    Unlocking the rich harvest of marine microbial ecosystems has the potential to both safeguard the existence of our species for the future, while also presenting significant lifestyle benefits for commercial gain. However, while significant advances have been made in the field of marine biodiscovery, leading to the introduction of new classes of therapeutics for clinical medicine, cosmetics and industrial products, much of what this natural ecosystem has to offer is locked in, and essentially hidden from our screening methods. Releasing this silent potential represents a significant technological challenge, the key to which is a comprehensive understanding of what controls these systems. Heterologous expression systems have been successful in awakening a number of these cryptic marine biosynthetic gene clusters (BGCs). However, this approach is limited by the typically large size of the encoding sequences. More recently, focus has shifted to the regulatory proteins associated with each BGC, many of which are signal responsive raising the possibility of exogenous activation. Abundant among these are the LysR-type family of transcriptional regulators, which are known to control production of microbial aromatic systems. Although the environmental signals that activate these regulatory systems remain unknown, it offers the exciting possibility of evoking mimic molecules and synthetic expression systems to drive production of potentially novel natural products in microorganisms. Success in this field has the potential to provide a quantum leap forward in medical and industrial bio-product development. To achieve these new endpoints, it is clear that the integrated efforts of bioinformaticians and natural product chemists will be required as we strive to uncover new and potentially unique structures from silent or cryptic marine gene clusters. PMID:26264003

  16. A Sound Therapy-Based Intervention to Expand the Auditory Dynamic Range for Loudness among Persons with Sensorineural Hearing Losses: A Randomized Placebo-Controlled Clinical Trial

    PubMed Central

    Formby, Craig; Hawley, Monica L.; Sherlock, LaGuinn P.; Gold, Susan; Payne, JoAnne; Brooks, Rebecca; Parton, Jason M.; Juneau, Roger; Desporte, Edward J.; Siegle, Gregory R.

    2015-01-01

    The primary aim of this research was to evaluate the validity, efficacy, and generalization of principles underlying a sound therapy–based treatment for promoting expansion of the auditory dynamic range (DR) for loudness. The basic sound therapy principles, originally devised for treatment of hyperacusis among patients with tinnitus, were evaluated in this study in a target sample of unsuccessfully fit and/or problematic prospective hearing aid users with diminished DRs (owing to their elevated audiometric thresholds and reduced sound tolerance). Secondary aims included: (1) delineation of the treatment contributions from the counseling and sound therapy components to the full-treatment protocol and, in turn, the isolated treatment effects from each of these individual components to intervention success; and (2) characterization of the respective dynamics for full, partial, and control treatments. Thirty-six participants with bilateral sensorineural hearing losses and reduced DRs, which affected their actual or perceived ability to use hearing aids, were enrolled in and completed a placebo-controlled (for sound therapy) randomized clinical trial. The 2 × 2 factorial trial design was implemented with or without various assignments of counseling and sound therapy. Specifically, participants were assigned randomly to one of four treatment groups (nine participants per group), including: (1) group 1—full treatment achieved with scripted counseling plus sound therapy implemented with binaural sound generators; (2) group 2—partial treatment achieved with counseling and placebo sound generators (PSGs); (3) group 3—partial treatment achieved with binaural sound generators alone; and (4) group 4—a neutral control treatment implemented with the PSGs alone. Repeated measurements of categorical loudness judgments served as the primary outcome measure. The full-treatment categorical-loudness judgments for group 1, measured at treatment termination, were

  17. Sound Absorbers

    NASA Astrophysics Data System (ADS)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  18. Human amygdala activation by the sound produced during dental treatment: A fMRI study.

    PubMed

    Yu, Jen-Fang; Lee, Kun-Che; Hong, Hsiang-Hsi; Kuo, Song-Bor; Wu, Chung-De; Wai, Yau-Yau; Chen, Yi-Fen; Peng, Ying-Chin

    2015-01-01

    During dental treatments, patients may experience negative emotions associated with the procedure. This study was conducted with the aim of using functional magnetic resonance imaging (fMRI) to visualize cerebral cortical stimulation among dental patients in response to auditory stimuli produced by ultrasonic scaling and power suction equipment. Subjects (n = 7) aged 23-35 years were recruited for this study. All were right-handed and underwent clinical pure-tone audiometry testing to reveal a normal hearing threshold below 20 dB hearing level (HL). As part of the study, subjects initially underwent a dental calculus removal treatment. During the treatment, subjects were exposed to ultrasonic auditory stimuli originating from the scaling handpiece and salivary suction instruments. After dental treatment, subjects were imaged with fMRI while being exposed to recordings of the noise from the same dental instrument so that cerebral cortical stimulation in response to aversive auditory stimulation could be observed. The independent sample confirmatory t-test was used. Subjects also showed stimulation in the amygdala and prefrontal cortex, indicating that the ultrasonic auditory stimuli elicited an unpleasant response in the subjects. Patients experienced unpleasant sensations caused by contact stimuli in the treatment procedure. In addition, this study has demonstrated that aversive auditory stimuli such as sounds from the ultrasonic scaling handpiece also cause aversive emotions. This study was indicated by observed stimulation of the auditory cortex as well as the amygdala, indicating that noise from the ultrasonic scaling handpiece was perceived as an aversive auditory stimulus by the subjects. Subjects can experience unpleasant sensations caused by the sounds from the ultrasonic scaling handpiece based on their auditory stimuli.

  19. Human amygdala activation by the sound produced during dental treatment: A fMRI study.

    PubMed

    Yu, Jen-Fang; Lee, Kun-Che; Hong, Hsiang-Hsi; Kuo, Song-Bor; Wu, Chung-De; Wai, Yau-Yau; Chen, Yi-Fen; Peng, Ying-Chin

    2015-01-01

    During dental treatments, patients may experience negative emotions associated with the procedure. This study was conducted with the aim of using functional magnetic resonance imaging (fMRI) to visualize cerebral cortical stimulation among dental patients in response to auditory stimuli produced by ultrasonic scaling and power suction equipment. Subjects (n = 7) aged 23-35 years were recruited for this study. All were right-handed and underwent clinical pure-tone audiometry testing to reveal a normal hearing threshold below 20 dB hearing level (HL). As part of the study, subjects initially underwent a dental calculus removal treatment. During the treatment, subjects were exposed to ultrasonic auditory stimuli originating from the scaling handpiece and salivary suction instruments. After dental treatment, subjects were imaged with fMRI while being exposed to recordings of the noise from the same dental instrument so that cerebral cortical stimulation in response to aversive auditory stimulation could be observed. The independent sample confirmatory t-test was used. Subjects also showed stimulation in the amygdala and prefrontal cortex, indicating that the ultrasonic auditory stimuli elicited an unpleasant response in the subjects. Patients experienced unpleasant sensations caused by contact stimuli in the treatment procedure. In addition, this study has demonstrated that aversive auditory stimuli such as sounds from the ultrasonic scaling handpiece also cause aversive emotions. This study was indicated by observed stimulation of the auditory cortex as well as the amygdala, indicating that noise from the ultrasonic scaling handpiece was perceived as an aversive auditory stimulus by the subjects. Subjects can experience unpleasant sensations caused by the sounds from the ultrasonic scaling handpiece based on their auditory stimuli. PMID:26356376

  20. Active control of fan-generated plane wave noise

    NASA Astrophysics Data System (ADS)

    Gerhold, Carl H.; Nuckolls, William E.; Santamaria, Odillyn L.; Martinson, Scott D.

    1993-08-01

    Subsonic propulsion systems for future aircraft may incorporate ultra-high bypass ratio ducted fan engines whose dominant noise source is the fan with blade passage frequency less than 1000 Hz. This low frequency combines with the requirement of a short nacelle to diminish the effectiveness of passive duct liners. Active noise control is seen as a viable method to augment the conventional passive treatments. An experiment to control ducted fan noise using a time domain active adaptive system is reported. The control sound source consists of loudspeakers arrayed around the fan duct. The error sensor location is in the fan duct. The purpose of this experiment is to demonstrate that the in-duct error sensor reduces the mode spillover in the far field, thereby increasing the efficiency of the control system. In this first series of tests, the fan is configured so that predominantly zero order circumferential waves are generated. The control system is found to reduce the blade passage frequency tone significantly in the acoustic far field when the mode orders of the noise source and of the control source are the same. The noise reduction is not as great when the mode orders are not the same even though the noise source modes are evanescent, but the control system converges stably and global noise reduction is demonstrated in the far field. Further experimentation is planned in which the performance of the system will be evaluated when higher order radial and spinning modes are generated.

  1. Active control of fan-generated plane wave noise

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.; Nuckolls, William E.; Santamaria, Odillyn L.; Martinson, Scott D.

    1993-01-01

    Subsonic propulsion systems for future aircraft may incorporate ultra-high bypass ratio ducted fan engines whose dominant noise source is the fan with blade passage frequency less than 1000 Hz. This low frequency combines with the requirement of a short nacelle to diminish the effectiveness of passive duct liners. Active noise control is seen as a viable method to augment the conventional passive treatments. An experiment to control ducted fan noise using a time domain active adaptive system is reported. The control sound source consists of loudspeakers arrayed around the fan duct. The error sensor location is in the fan duct. The purpose of this experiment is to demonstrate that the in-duct error sensor reduces the mode spillover in the far field, thereby increasing the efficiency of the control system. In this first series of tests, the fan is configured so that predominantly zero order circumferential waves are generated. The control system is found to reduce the blade passage frequency tone significantly in the acoustic far field when the mode orders of the noise source and of the control source are the same. The noise reduction is not as great when the mode orders are not the same even though the noise source modes are evanescent, but the control system converges stably and global noise reduction is demonstrated in the far field. Further experimentation is planned in which the performance of the system will be evaluated when higher order radial and spinning modes are generated.

  2. Active control of combustion instability

    SciTech Connect

    Lang, W.; Poinsot, T.; Candel, S.

    1987-12-01

    The principle of 'antisound' is used to construct a method for the suppression of combustion instabilities. This active instability control (AIC) method uses external acoustic excitation by a loudspeaker to suppress the oscillations of a flame. The excitation signal is provided by a microphone located upstream of the flame. This signal is filtered, processed, amplified, and sent to the loudspeaker. The AIC method is validated on a laboratory combustor. It allows the suppression of all unstable modes of the burner for any operating ratio. The influence of the microphone and loudspeaker locations on the performance of the AIC system is described. For a given configuration, domains of stability, i.e., domains where the AIC system parameters provide suppression of the oscillation, are investigated. Measurements of the electric input of the loudspeaker show that the energy consumption of the AIC system is almost negligible and suggest that this method could be used for industrial combustor stabilization. Finally, a simple model describing the effects of the AIC system is developed and its results compared to the experiment.

  3. Active thermal control system evolution

    NASA Technical Reports Server (NTRS)

    Petete, Patricia A.; Ames, Brian E.

    1991-01-01

    The 'restructured' baseline of the Space Station Freedom (SSF) has eliminated many of the growth options for the Active Thermal Control System (ATCS). Modular addition of baseline technology to increase heat rejection will be extremely difficult. The system design and the available real estate no longer accommodate this type of growth. As the station matures during its thirty years of operation, a demand of up to 165 kW of heat rejection can be expected. The baseline configuration will be able to provide 82.5 kW at Eight Manned Crew Capability (EMCC). The growth paths necessary to reach 165 kW have been identified. Doubling the heat rejection capability of SSF will require either the modification of existing radiator wings or the attachment of growth structure to the baseline truss for growth radiator wing placement. Radiator performance can be improved by enlarging the surface area or by boosting the operating temperature with a heat pump. The optimal solution will require both modifications. The addition of growth structure would permit the addition of a parallel ATCS using baseline technology. This growth system would simplify integration. The feasibility of incorporating these growth options to improve the heat rejection capacity of SSF is under evaluation.

  4. Horizontal coherence of low-frequency fixed-path sound in a continental shelf region with internal-wave activity.

    PubMed

    Duda, Timothy F; Collis, Jon M; Lin, Ying-Tsong; Newhall, Arthur E; Lynch, James F; DeFerrari, Harry A

    2012-02-01

    Sound at 85 to 450 Hz propagating in approximately 80-m depth water from fixed sources to a joint horizontal/vertical line array (HLA/VLA) is analyzed. The data are from a continental shelf area east of Delaware Bay (USA) populated with tidally generated long- and short-wavelength internal waves. Sound paths are 19 km in the along-shore (along internal-wave crest) direction and 30 km in the cross-shore direction. Spatial statistics of HLA arrivals are computed as functions of beam steering angle and time. These include array gain, horizontally lagged spatial correlation function, and coherent beam power. These quantities vary widely in magnitude, and vary over a broad range of time scales. For example, correlation scale can change rapidly from forty to five wavelengths, and correlation-scale behavior is anisotropic. In addition, the vertical array can be used to predict correlation expected for adiabatic propagation with cylindrical symmetry, forming a benchmark. Observed variations are in concert with internal-wave activity. Temporal variations of three coherence measures, horizontal correlation length, array gain, and ratio of actual correlation length to predicted adiabatic-mode correlation length, are very strong, varying by almost a factor of ten as internal waves pass.

  5. Sounds of marine seeps: a study of bubble activity near a rigid boundary.

    PubMed

    Maksimov, A O; Burov, B A; Salomatin, A S; Chernykh, D V

    2014-09-01

    A passive acoustic method for detecting environmentally dangerous gas leaks from pipelines and methane naturally leaking from the seabed has been investigated. Gas escape involves the formation and release of bubbles of different sizes. Each bubble emits a sound at a specific frequency. Determination of the bubble radius from the frequency of its signature passive acoustic emission by use of so-called Minnaert formula has a restricted area of applicability near the seabed. The point is that the inertial mass and the damping constant of the birthing bubble are markedly different from those of a free bubble. The theoretical model for the bubble volume oscillations near the seabed has been proposed and an analytical solution has been derived. It was shown that the bispherical coordinates provide separation of variables and are more suitable for analysis of the volume oscillations of these constrained bubbles. Explicit formulas have been derived, which describe the dependence of the bubble emission near a rigid wall on its size and the separation distance between the bubble and the boundary. PMID:25190382

  6. Adjoint-field errors in high fidelity compressible turbulence simulations for sound control

    NASA Astrophysics Data System (ADS)

    Vishnampet, Ramanathan; Bodony, Daniel; Freund, Jonathan

    2013-11-01

    A consistent discrete adjoint for high-fidelity discretization of the three-dimensional Navier-Stokes equations is used to quantify the error in the sensitivity gradient predicted by the continuous adjoint method, and examine the aeroacoustic flow-control problem for free-shear-flow turbulence. A particular quadrature scheme for approximating the cost functional makes our discrete adjoint formulation for a fourth-order Runge-Kutta scheme with high-order finite differences practical and efficient. The continuous adjoint-based sensitivity gradient is shown to to be inconsistent due to discretization truncation errors, grid stretching and filtering near boundaries. These errors cannot be eliminated by increasing the spatial or temporal resolution since chaotic interactions lead them to become O (1) at the time of control actuation. Although this is a known behavior for chaotic systems, its effect on noise control is much harder to anticipate, especially given the different resolution needs of different parts of the turbulence and acoustic spectra. A comparison of energy spectra of the adjoint pressure fields shows significant error in the continuous adjoint at all wavenumbers, even though they are well-resolved. The effect of this error on the noise control mechanism is analyzed.

  7. Controlled Release Fertilizers: An Environmentally Sound and Efficient Method for Greenhouse Crop Fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lake Erie is the most polluted of all the Great Lakes. In fact, the Maumee River Watershed alone contributes most of Lake Erie’s phosphorus and sediment load but only 3% of its water, due to the large concentration of agriculture in this portion of the state. The use of controlled release fertilize...

  8. Dynamic cognitive control of irrelevant sound: Increased task engagement attenuates semantic auditory distraction.

    PubMed

    Marsh, John E; Sörqvist, Patrik; Hughes, Robert W

    2015-10-01

    Two experiments investigated reactive top-down cognitive control of the detrimental influence of spoken distractors semantically related to words presented visually for free recall. Experiment 1 demonstrated that an increase in focal-task engagement-promoted experimentally by reducing the perceptual discriminability of the visual target words-eliminated the disruption by such distractors of veridical recall and also attenuated the erroneous recall of the distractors. A recall instruction that eliminates the requirement for output monitoring was used in Experiment 2 to investigate whether increased task engagement shields against distraction through a change in output-monitoring processes (back-end control) or by affecting the processing of the distractors during their presentation (front-end control). Rates of erroneous distractor recall were much greater than in Experiment 1, but both erroneous distractor recall and the disruptive effect of distractors on veridical recall were still attenuated under reduced target-word discriminability. Taken together, the results show that task engagement is under dynamic strategic control and can be modulated to shield against auditory distraction by attenuating distractor processing at encoding, thereby preventing distractors from coming to mind at test. (PsycINFO Database Record

  9. 75 FR 38406 - Amendment of Norton Sound Low and Control 1234L Offshore Airspace Areas; Alaska

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-02

    ... Bay; within 74 miles of Elim and Manokotak, and within 72.5 miles of Red Dog. The Control 1234L... Noatak Airport, AK, and within a 72.5-mile radius of the Red Dog Airport, AK, and within a 73-mile radius... 1234L (75 FR 16024). Interested parties were invited to participate in this rulemaking effort...

  10. Dynamic cognitive control of irrelevant sound: Increased task engagement attenuates semantic auditory distraction.

    PubMed

    Marsh, John E; Sörqvist, Patrik; Hughes, Robert W

    2015-10-01

    Two experiments investigated reactive top-down cognitive control of the detrimental influence of spoken distractors semantically related to words presented visually for free recall. Experiment 1 demonstrated that an increase in focal-task engagement-promoted experimentally by reducing the perceptual discriminability of the visual target words-eliminated the disruption by such distractors of veridical recall and also attenuated the erroneous recall of the distractors. A recall instruction that eliminates the requirement for output monitoring was used in Experiment 2 to investigate whether increased task engagement shields against distraction through a change in output-monitoring processes (back-end control) or by affecting the processing of the distractors during their presentation (front-end control). Rates of erroneous distractor recall were much greater than in Experiment 1, but both erroneous distractor recall and the disruptive effect of distractors on veridical recall were still attenuated under reduced target-word discriminability. Taken together, the results show that task engagement is under dynamic strategic control and can be modulated to shield against auditory distraction by attenuating distractor processing at encoding, thereby preventing distractors from coming to mind at test. (PsycINFO Database Record PMID:26191618

  11. GPS Sounding Rocket Developments

    NASA Technical Reports Server (NTRS)

    Bull, Barton

    1999-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads several hundred miles in altitude. These missions return a variety of scientific data including; chemical makeup and physical processes taking place in the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft prior to their use in more expensive activities. This paper addresses the NASA Wallops Island history of GPS Sounding Rocket experience since 1994 and the development of highly accurate and useful system.

  12. Phytoremediation: An Environmentally Sound Technology for Pollution Prevention, Control and Remediation in Developing Countries

    ERIC Educational Resources Information Center

    Erakhrumen, Andrew Agbontalor

    2007-01-01

    The problem of environmental pollution has assumed an unprecedented proportion in many parts of the world especially in Nigeria and its Niger-Delta region in particular. This region is bedeviled with this problem perhaps owing to interplay of demographic and socio-economic forces coupled with the various activities that revolve round the…

  13. Does the sound of a barking dog activate its corresponding visual form? An fMRI investigation of modality-specific semantic access.

    PubMed

    Reilly, Jamie; Garcia, Amanda; Binney, Richard J

    2016-08-01

    Much remains to be learned about the neural architecture underlying word meaning. Fully distributed models of semantic memory predict that the sound of a barking dog will conjointly engage a network of distributed sensorimotor spokes. An alternative framework holds that modality-specific features additionally converge within transmodal hubs. Participants underwent functional MRI while covertly naming familiar objects versus newly learned novel objects from only one of their constituent semantic features (visual form, characteristic sound, or point-light motion representation). Relative to the novel object baseline, familiar concepts elicited greater activation within association regions specific to the presentation modality. Furthermore, visual form elicited activation within high-level auditory association cortex. Conversely, environmental sounds elicited activation in regions proximal to visual association cortex. Both conditions commonly engaged a putative hub region within lateral anterior temporal cortex. These results support hybrid semantic models in which local hubs and distributed spokes are dually engaged in service of semantic memory. PMID:27289210

  14. Active structural acoustic control of a smart cylindrical shell using a virtual microphone

    NASA Astrophysics Data System (ADS)

    Loghmani, Ali; Danesh, Mohammad; Kwak, Moon K.; Keshmiri, Mehdi

    2016-04-01

    This paper investigates the active structural acoustic control of sound radiated from a smart cylindrical shell. The cylinder is equipped with piezoelectric sensors and actuators to estimate and control the sound pressure that radiates from the smart shell. This estimated pressure is referred to as a virtual microphone, and it can be used in control systems instead of actual microphones to attenuate noise due to structural vibrations. To this end, the dynamic model for the smart cylinder is derived using the extended Hamilton’s principle, the Sanders shell theory and the assumed mode method. The simplified Kirchhoff-Helmholtz integral estimates the far-field sound pressure radiating from the baffled cylindrical shell. A modified higher harmonic controller that can cope with a harmonic disturbance is designed and experimentally evaluated. The experimental tests were carried out on a baffled cylindrical aluminum shell in an anechoic chamber. The frequency response for the theoretical virtual microphone and the experimental actual microphone are in good agreement with each other, and the results show the effectiveness of the designed virtual microphone and controller in attenuating the radiated sound.

  15. Nonlethal combined flash and sound pulse projector for counter-personnel and crowd control

    NASA Astrophysics Data System (ADS)

    Schaefer, Raymond; Grapperhaus, Michael

    2006-05-01

    This paper presents a non-lethal concept using an innovative directed energy pulser for counter-personnel and crowd control. A high power pulsed electrical discharge, initiated using a wire in air, simultaneously generates a loud acoustic report and a bright light pulse. A reflector directs and focuses the 'flash/bang' to deliver high intensity pulses at range. The counter-personnel and crowd control effect is variable through both the intensity of each pulse and the pulse repetition rate. The system can be battery powered, and man portable or mounted on a jeep or other vehicle. This 'air sparker' is different from existing flash-bang approaches which employ a chemical reaction from a 'grenade', and different from laser approaches that generate a plasma in the vicinity of the targeted personnel. A design example using quantitative laboratory measurements, and reflector design and modeling, exhibits the output potential of air sparkers. Using generic non-lethal effects available in the open literature, the design example indicates that air sparker technology may have widespread non-lethal applicability. New sparker technology can lead to compact efficient systems. Development of air sparkers for non-lethal counter-personnel and crowd control should address both the technology and the combined effects.

  16. Active learning of novel sound-producing objects: motor reactivation and enhancement of visuo-motor connectivity.

    PubMed

    Butler, Andrew J; James, Karin Harman

    2013-02-01

    Our experience with the world commonly involves physical interaction with objects enabling us to learn associations between multisensory information perceived during an event and our actions that create an event. The interplay among active interactions during learning and multisensory integration of object properties is not well understood. To better understand how action might enhance multisensory associative recognition, we investigated the interplay among motor and perceptual systems after active learning. Fifteen participants were included in an fMRI study during which they learned visuo-auditory-motor associations between novel objects and the sounds they produce, either through self-generated actions on the objects (active learning) or by observing an experimenter produce the actions (passive learning). Immediately after learning, behavioral and BOLD fMRI measures were collected while perceiving the objects used during unisensory and multisensory training in associative perception and recognition tasks. Active learning was faster and led to more accurate recognition of audiovisual associations than passive learning. Functional ROI analyses showed that in motor, somatosensory, and cerebellar regions there was greater activation during both the perception and recognition of actively learned associations. Finally, functional connectivity between visual- and motor-related processing regions was enhanced during the presentation of actively learned audiovisual associations. Overall, the results of the current study clarify and extend our own previous work [Butler, A. J., James, T. W., & Harman James, K. Enhanced multisensory integration and motor reactivation after active motor learning of audiovisual associations. Journal of Cognitive Neuroscience, 23, 3515-3528, 2011] by providing several novel findings and highlighting the task-based nature of motor reactivation and retrieval after active learning.

  17. Active Control of Fan Noise by Vane Actuators

    NASA Technical Reports Server (NTRS)

    Curtis, Alan R. D.

    1999-01-01

    An active noise control system for ducted fan noise was built that uses actuators located in stator vanes. The actuators were piezoelectric benders manufactured using the THUNDER technology and were custom designed for the application. The active noise control system was installed in the NASA ANCF rig. Four actuator array with a total of 168 actuators in 28 stator vanes were used. Simultaneous reductions of acoustic power in both the inlet and exhaust duct were demonstrated for a fan disturbance that contained two radial mode orders in both inlet and exhaust. Total power levels in the target modes were reduced by up to 9 dB in the inlet and total tone levels by over 6 dB while exhaust power levels were reduced by up to 3 dB. Far field sound pressure level reductions of up to 17 dB were observed. A simpler control system, matched to the location of the disturbance with two radial actuator arrays, was demonstrated to control total acoustic power in four disturbance modes simultaneously in inlet and exhaust. The vane actuator met the requirements given for the ANCF, although in practice the performance of the system was limited by the constraints of the power amplifiers and the presence of control spillover. The vane actuators were robust. None of the 168 vane actuators failed during the tests.

  18. Hybrid phononic crystals for broad-band frequency noise control by sound blocking and localization.

    PubMed

    Yoo, Sungmin; Kim, Yoon Jae; Kim, Yoon Young

    2012-11-01

    A bandgap cannot be enlarged sufficiently enough to suppress a broad-band noise only with a single type of finite-length phononic crystals. Here, a hybrid phononic crystal consisting of a bi-prism and an inverted bi-prism is proposed for noise control in a broad band; a stop band is formed in a central frequency range while positive-positive and positive-negative refractions occur in lower and higher frequency ranges to concentrate acoustic energy in a central localized zone. Thereby, the remaining zone becomes little affected by the noise. Analysis and numerical simulations are given for the justification of the proposed configuration. PMID:23145703

  19. Effects of Listening to Music versus Environmental Sounds in Passive and Active Situations on Levels of Pain and Fatigue in Fibromyalgia.

    PubMed

    Mercadíe, Lolita; Mick, Gérard; Guétin, Stéphane; Bigand, Emmanuel

    2015-10-01

    In fibromyalgia, pain symptoms such as hyperalgesia and allodynia are associated with fatigue. Mechanisms underlying such symptoms can be modulated by listening to pleasant music. We expected that listening to music, because of its emotional impact, would have a greater modulating effect on the perception of pain and fatigue in patients with fibromyalgia than listening to nonmusical sounds. To investigate this hypothesis, we carried out a 4-week study in which patients with fibromyalgia listened to either preselected musical pieces or environmental sounds when they experienced pain in active (while carrying out a physical activity) or passive (at rest) situations. Concomitant changes of pain and fatigue levels were evaluated. When patients listened to music or environmental sounds at rest, pain and fatigue levels were significantly reduced after 20 minutes of listening, with no difference of effect magnitude between the two stimuli. This improvement persisted 10 minutes after the end of the listening session. In active situations, pain did not increase in presence of the two stimuli. Contrary to our expectations, music and environmental sounds produced a similar relieving effect on pain and fatigue, with no benefit gained by listening to pleasant music over environmental sounds.

  20. Effects of Listening to Music versus Environmental Sounds in Passive and Active Situations on Levels of Pain and Fatigue in Fibromyalgia.

    PubMed

    Mercadíe, Lolita; Mick, Gérard; Guétin, Stéphane; Bigand, Emmanuel

    2015-10-01

    In fibromyalgia, pain symptoms such as hyperalgesia and allodynia are associated with fatigue. Mechanisms underlying such symptoms can be modulated by listening to pleasant music. We expected that listening to music, because of its emotional impact, would have a greater modulating effect on the perception of pain and fatigue in patients with fibromyalgia than listening to nonmusical sounds. To investigate this hypothesis, we carried out a 4-week study in which patients with fibromyalgia listened to either preselected musical pieces or environmental sounds when they experienced pain in active (while carrying out a physical activity) or passive (at rest) situations. Concomitant changes of pain and fatigue levels were evaluated. When patients listened to music or environmental sounds at rest, pain and fatigue levels were significantly reduced after 20 minutes of listening, with no difference of effect magnitude between the two stimuli. This improvement persisted 10 minutes after the end of the listening session. In active situations, pain did not increase in presence of the two stimuli. Contrary to our expectations, music and environmental sounds produced a similar relieving effect on pain and fatigue, with no benefit gained by listening to pleasant music over environmental sounds. PMID:26163741

  1. Dog-appeasing pheromone collars reduce sound-induced fear and anxiety in beagle dogs: a placebo-controlled study.

    PubMed

    Landsberg, G M; Beck, A; Lopez, A; Deniaud, M; Araujo, J A; Milgram, N W

    2015-09-12

    The objective of the study was to assess the effects of a dog-appeasing pheromone (DAP) collar in reducing sound-induced fear and anxiety in a laboratory model of thunderstorm simulation. Twenty-four beagle dogs naïve to the current test were divided into two treatment groups (DAP and placebo) balanced on their fear score in response to a thunderstorm recording. Each group was then exposed to two additional thunderstorm simulation tests on consecutive days. Dogs were video-assessed by a trained observer on a 6-point scale for active, passive and global fear and anxiety (combined). Both global and active fear and anxiety scores were significantly improved during and following thunder compared with placebo on both test days. DAP significantly decreased global fear and anxiety across 'during' and 'post' thunder times when compared with baseline. There was no significant improvement in the placebo group from baseline on the test days. In addition, the DAP group showed significantly greater use of the hide box at any time with increased exposure compared with the placebo group. The DAP collar reduced the scores of fear and anxiety, and increased hide use in response to a thunder recording, possibly by counteracting noise-related increased reactivity. PMID:26311736

  2. Dog-appeasing pheromone collars reduce sound-induced fear and anxiety in beagle dogs: a placebo-controlled study

    PubMed Central

    Landsberg, G. M.; Beck, A.; Lopez, A.; Deniaud, M.; Araujo, J. A.; Milgram, N. W.

    2015-01-01

    The objective of the study was to assess the effects of a dog-appeasing pheromone (DAP) collar in reducing sound-induced fear and anxiety in a laboratory model of thunderstorm simulation. Twenty-four beagle dogs naïve to the current test were divided into two treatment groups (DAP and placebo) balanced on their fear score in response to a thunderstorm recording. Each group was then exposed to two additional thunderstorm simulation tests on consecutive days. Dogs were video-assessed by a trained observer on a 6-point scale for active, passive and global fear and anxiety (combined). Both global and active fear and anxiety scores were significantly improved during and following thunder compared with placebo on both test days. DAP significantly decreased global fear and anxiety across ‘during’ and ‘post’ thunder times when compared with baseline. There was no significant improvement in the placebo group from baseline on the test days. In addition, the DAP group showed significantly greater use of the hide box at any time with increased exposure compared with the placebo group. The DAP collar reduced the scores of fear and anxiety, and increased hide use in response to a thunder recording, possibly by counteracting noise-related increased reactivity. PMID:26311736

  3. Dog-appeasing pheromone collars reduce sound-induced fear and anxiety in beagle dogs: a placebo-controlled study.

    PubMed

    Landsberg, G M; Beck, A; Lopez, A; Deniaud, M; Araujo, J A; Milgram, N W

    2015-09-12

    The objective of the study was to assess the effects of a dog-appeasing pheromone (DAP) collar in reducing sound-induced fear and anxiety in a laboratory model of thunderstorm simulation. Twenty-four beagle dogs naïve to the current test were divided into two treatment groups (DAP and placebo) balanced on their fear score in response to a thunderstorm recording. Each group was then exposed to two additional thunderstorm simulation tests on consecutive days. Dogs were video-assessed by a trained observer on a 6-point scale for active, passive and global fear and anxiety (combined). Both global and active fear and anxiety scores were significantly improved during and following thunder compared with placebo on both test days. DAP significantly decreased global fear and anxiety across 'during' and 'post' thunder times when compared with baseline. There was no significant improvement in the placebo group from baseline on the test days. In addition, the DAP group showed significantly greater use of the hide box at any time with increased exposure compared with the placebo group. The DAP collar reduced the scores of fear and anxiety, and increased hide use in response to a thunder recording, possibly by counteracting noise-related increased reactivity.

  4. Developing Internal Controls through Activities

    ERIC Educational Resources Information Center

    Barnes, F. Herbert

    2009-01-01

    Life events can include the Tuesday afternoon cooking class with the group worker or the Saturday afternoon football game, but in the sense that Fritz Redl thought of them, these activities are only threads in a fabric of living that includes all the elements of daily life: playing, working, school-based learning, learning through activities,…

  5. The role of central parts of the brain in the control of sound production during courtship in Drosophila melanogaster.

    PubMed

    Popov, A V; Sitnik, N A; Savvateeva-Popova, E V; Wolf, R; Heisenberg, M

    2003-01-01

    The question of the roles of the two main parts of the insect brain, the mushroom bodies and the central complex, in controlling motor coordination and triggering a variety of behavioral programs, including sound production, remains controversial. With the aim of improving our understanding of this question, we studied the parameters of songs used by five-day-old males during courtship for fertilized wild-type females (Canton-S, C-S) over 5-min periods at 25 degrees C; males were of two wild-type Drosophila melanogaster lines (Berlin and C-S). Berlin males lacking mushroom bodies because of treatment with hydroxyurea during development (chemical removal of the mushroom bodies) were used, along with two mutants with defects in the mushroom bodies (mbm1 and mud1), two mutants with defects in the central complex (ccbKS127 and cexKS181), and mutant cxbN71 with defects in both the mushroom bodies and the central complex. The experiments reported here showed that courtship songs in males lacking mushroom bodies were virtually identical to those of wild-type males. The main parameters of pulsatile song in mutants mbm1 and mud1 (interpulse interval and train duration) were insignificantly different from those of the songs of wild-type flies, though the stability of the pulse oscillator was the same. Flies of these lines were no different from wild-type flies in terms of courtship success (percentage of copulating pairs in 10-min tests). Conversely, the songs of mutants with defects in the central complex differed from those of wild-type males. Firstly, there was degradation of the stability of the pulse oscillator and interpulse intervals were very variable. In addition, pulses were often significantly longer and appeared multicyclic, as in the well-known cacophony mutant, while the mean train duration was significantly shorter. Males of the line cexKS181 usually courted very intensely, though abnormal sounds were generally emitted. Mutants cexKS181 and ccbKS127 were

  6. Orbiter active thermal control system description

    NASA Technical Reports Server (NTRS)

    Laubach, G. E.

    1975-01-01

    A brief description of the Orbiter Active Thermal Control System (ATCS) including (1) major functional requirements of heat load, temperature control and heat sink utilization, (2) the overall system arrangement, and (3) detailed description of the elements of the ATCS.

  7. A Benthic Invertebrate Survey of Jun Jaegyu Volcano: An active undersea volcano in Antarctic Sound, Antarctica

    NASA Astrophysics Data System (ADS)

    Quinones, G.; Brachfeld, S.; Gorring, M.; Prezant, R. S.; Domack, E.

    2005-12-01

    Jun Jaegyu volcano, an Antarctic submarine volcano, was dredged in May 2004 during cruise 04-04 of the RV Laurence M. Gould to determine rock, sediment composition and marine macroinvertebrate diversity. The objectives of this study are to examine the benthic assemblages and biodiversity present on a young volcano. The volcano is located on the continental shelf of the northeastern Antarctic Peninsula, where recent changes in surface temperature and ice shelf stability have been observed. This volcano was originally swath-mapped during cruise 01-07 of the Research Vessel-Ice Breaker Nathaniel B. Palmer. During LMG04-04 we also studied the volcano using a SCUD video camera, and performed temperature surveys along the flanks and crest. Both the video and the dredge indicate a seafloor surface heavily colonized by benthic organisms. Indications of fairly recent lava flows are given by the absence of marine life on regions of the volcano. The recovered dredge material was sieved, and a total of thirty-three invertebrates were extracted. The compilation of invertebrate community data can subsequently be compared to other benthic invertebrate studies conducted along the peninsula, which can determine the regional similarity of communities over time, their relationship to environmental change and health, if any, and their relationship to geologic processes in Antarctic Sound. Twenty-two rock samples, all slightly weathered and half bearing encrusted organisms, were also analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES). Except for one conglomerate sample, all are alkali basalts and share similar elemental compositions with fresh, unweathered samples from the volcano. Two of the encrusted basalt samples have significantly different compositions than the rest. We speculate this difference could be due to water loss during sample preparation, loss of organic carbon trapped within the vesicles of the samples and/or elemental uptake by the

  8. The Middeck Active Control Experiment (MACE)

    NASA Technical Reports Server (NTRS)

    Miller, David W.

    1992-01-01

    Viewgraphs on the Middeck Active Control Experiment (MACE) are presented. Topics covered include: program objectives; program features; flight experiment features; current activities; MACE development model lab testing; MACE test article deployed on STS middeck; and development model testing.

  9. Active control of panel vibrations induced by a boundary layer flow

    NASA Technical Reports Server (NTRS)

    Chow, Pao-Liu

    1995-01-01

    The problems of active and passive control of sound and vibration has been investigated by many researchers for a number of years. However, few of the articles are concerned with the sound and vibration with flow-structure interaction. Experimental and numerical studies on the coupling between panel vibration and acoustic radiation due to flow excitation have been done by Maestrello and his associates at NASA/Langley Research Center. Since the coupled system of nonlinear partial differential equations is formidable, an analytical solution to the full problem seems impossible. For this reason, we have to simplify the problem to that of the nonlinear panel vibration induced by a uniform flow or a boundary-layer flow with a given wall pressure distribution. Based on this simplified model, we have been able to consider the control and stabilization of the nonlinear panel vibration, which have not been treated satisfactorily by other authors. Although the sound radiation has not been included, the vibration suppression will clearly reduce the sound radiation power from the panel. The major research findings are presented in three sections. In section two we describe results on the boundary control of nonlinear panel vibration, with or without flow excitation. Sections three and four are concerned with some analytical and numerical results in the optimal control of the linear and nonlinear panel vibrations, respectively, excited by the flow pressure fluctuations. Finally, in section five, we draw some conclusions from research findings.

  10. The Sounds of Sentences: Differentiating the Influence of Physical Sound, Sound Imagery, and Linguistically Implied Sounds on Physical Sound Processing.

    PubMed

    Dudschig, Carolin; Mackenzie, Ian Grant; Strozyk, Jessica; Kaup, Barbara; Leuthold, Hartmut

    2016-10-01

    Both the imagery literature and grounded models of language comprehension emphasize the tight coupling of high-level cognitive processes, such as forming a mental image of something or language understanding, and low-level sensorimotor processes in the brain. In an electrophysiological study, imagery and language processes were directly compared and the sensory associations of processing linguistically implied sounds or imagined sounds were investigated. Participants read sentences describing auditory events (e.g., "The dog barks"), heard a physical (environmental) sound, or had to imagine such a sound. We examined the influence of the 3 sound conditions (linguistic, physical, imagery) on subsequent physical sound processing. Event-related potential (ERP) difference waveforms indicated that in all 3 conditions, prime compatibility influenced physical sound processing. The earliest compatibility effect was observed in the physical condition, starting in the 80-110 ms time interval with a negative maximum over occipital electrode sites. In contrast, the linguistic and the imagery condition elicited compatibility effects starting in the 180-220 ms time window with a maximum over central electrode sites. In line with the ERPs, the analysis of the oscillatory activity showed that compatibility influenced early theta and alpha band power changes in the physical, but not in the linguistic and imagery, condition. These dissociations were further confirmed by dipole localization results showing a clear separation between the source of the compatibility effect in the physical sound condition (superior temporal area) and the source of the compatibility effect triggered by the linguistically implied sounds or the imagined sounds (inferior temporal area). Implications for grounded models of language understanding are discussed. PMID:27473463

  11. The Sounds of Sentences: Differentiating the Influence of Physical Sound, Sound Imagery, and Linguistically Implied Sounds on Physical Sound Processing.

    PubMed

    Dudschig, Carolin; Mackenzie, Ian Grant; Strozyk, Jessica; Kaup, Barbara; Leuthold, Hartmut

    2016-10-01

    Both the imagery literature and grounded models of language comprehension emphasize the tight coupling of high-level cognitive processes, such as forming a mental image of something or language understanding, and low-level sensorimotor processes in the brain. In an electrophysiological study, imagery and language processes were directly compared and the sensory associations of processing linguistically implied sounds or imagined sounds were investigated. Participants read sentences describing auditory events (e.g., "The dog barks"), heard a physical (environmental) sound, or had to imagine such a sound. We examined the influence of the 3 sound conditions (linguistic, physical, imagery) on subsequent physical sound processing. Event-related potential (ERP) difference waveforms indicated that in all 3 conditions, prime compatibility influenced physical sound processing. The earliest compatibility effect was observed in the physical condition, starting in the 80-110 ms time interval with a negative maximum over occipital electrode sites. In contrast, the linguistic and the imagery condition elicited compatibility effects starting in the 180-220 ms time window with a maximum over central electrode sites. In line with the ERPs, the analysis of the oscillatory activity showed that compatibility influenced early theta and alpha band power changes in the physical, but not in the linguistic and imagery, condition. These dissociations were further confirmed by dipole localization results showing a clear separation between the source of the compatibility effect in the physical sound condition (superior temporal area) and the source of the compatibility effect triggered by the linguistically implied sounds or the imagined sounds (inferior temporal area). Implications for grounded models of language understanding are discussed.

  12. The Middeck Active Control Experiment (MACE): Identification for robust control

    NASA Technical Reports Server (NTRS)

    Karlov, Valery I.

    1992-01-01

    Viewgraphs on identification for robust control for the Middeck Active Control Experiment (MACE) are presented. Topics covered include: identification for robust control; three levels of identification; basic elements of the approach; advantages of 'post-ID' model of uncertainty; advantages of optimization; and practical realization.

  13. Using A-weighting for psychoacoustic active noise control.

    PubMed

    Bao, Hua; Panahi, Issa M S

    2009-01-01

    Conventional adaptive active noise control (ANC) methods aim to attenuate the acoustic noise over the frequency band of interest indiscriminately using the sound pressure level (SPL) measurement (or the measurement of the residual error variance). However, SPL does not correctly reflect the human perception of attenuated noise due to the frequency selective sensitivity of human hearing system. A-weighting is a commonly used weighting filter for measuring the noise. This weighting filter quantifies frequency response of the human ears and hearing system. In this paper, we aim to improve the performance of adaptive noise cancellation method from the psychoacoustic point of view by incorporating the A-weighting into the ANC system design. Loudness is used as the psychoacoustic criterion for evaluating the ANC system performance. Simulation results illustrate the effectiveness of the proposed method. PMID:19963645

  14. DHA but not EPA, enhances sound induced escape behavior and Mauthner cells activity in Sparus aurata.

    PubMed

    Benítez-Santana, Tibiábin; Atalah, Eyad; Betancor, Mónica Beatriz; Caballero, María José; Hernández-Cruz, Carmen Mari; Izquierdo, Marisol

    2014-01-30

    Dietary omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have a marked effect on fish behavior. There is limited information on the mechanisms involved in this effect and its relation to neuron development and functioning. Deficiency of n-3 LCPUFA reduces fish escape swimming. Mauthner cells (M-cell) are neurons responsible for initiating an escape response. The aim was to compare the effect of dietary DHA and EPA on escape behavior and neuronal activity of sea bream larvae. We studied burst swimming speed as a measure of behavior. M-cell activity was studied by ChAT immuno-fluorescence. Feeding the lowest n-3 LCPUFA levels a lower burst swimming speed. Increase in dietary EPA did not significantly improve escape response. Elevation of dietary DHA was correlated with a higher burst speed denoting the importance of this nutrient for escape swimming. Incorporation of DHA into larval tissues was proportional to DHA dietary levels and significantly correlated with burst speed. In addition, a higher immunoreactivity to ChAT, associated to a higher neural activity, was found in M-cell of larvae fed higher dietary DHA contents. These results show first evidence of n-3 LCPUFA on fish neuronal activity and their implications in behavior, denoting that DHA boosts escape swimming and this effect is at least partly mediated by the increase in neural activity of M-cell.

  15. Sound Guard

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Lubrication technology originally developed for a series of NASA satellites has produced a commercial product for protecting the sound fidelity of phonograph records. Called Sound Guard, the preservative is a spray-on fluid that deposits a microscopically thin protective coating which reduces friction and prevents the hard diamond stylus from wearing away the softer vinyl material of the disc. It is marketed by the Consumer Products Division of Ball Corporation, Muncie, Indiana. The lubricant technology on which Sound Guard is based originated with NASA's Orbiting Solar Observatory (OSO), an Earth-orbiting satellite designed and built by Ball Brothers Research Corporation, Boulder, Colorado, also a division of Ball Corporation. Ball Brothers engineers found a problem early in the OSO program: known lubricants were unsuitable for use on satellite moving parts that would be exposed to the vacuum of space for several months. So the company conducted research on the properties of materials needed for long life in space and developed new lubricants. They worked successfully on seven OSO flights and attracted considerable attention among other aerospace contractors. Ball Brothers now supplies its "Vac Kote" lubricants and coatings to both aerospace and non-aerospace industries and the company has produced several hundred variations of the original technology. Ball Corporation expanded its product line to include consumer products, of which Sound Guard is one of the most recent. In addition to protecting record grooves, Sound Guard's anti-static quality also retards particle accumulation on the stylus. During comparison study by a leading U.S. electronic laboratory, a record not treated by Sound Guard had to be cleaned after 50 plays and the stylus had collected a considerable number of small vinyl particles. The Sound Guard-treated disc was still clean after 100 plays, as was its stylus.

  16. Student Activity Funds: Procedures & Controls.

    ERIC Educational Resources Information Center

    Cuzzetto, Charles E.

    Student activity funds may create educational opportunities for students, but they frequently create problems for business administrators. The first part of this work reviews the types of organizational issues and transactions an organized student group is likely to encounter, including establishing a constitution, participant roles,…

  17. The effect of intranasal oxytocin versus placebo treatment on the autonomic responses to human sounds in autism: a single-blind, randomized, placebo-controlled, crossover design study

    PubMed Central

    2014-01-01

    Background Many individuals with autism spectrum disorders (ASD) have difficulty with verbal communication, which might be due to a lack of spontaneous orientation toward social auditory stimuli. Previous studies have shown that a single dose of oxytocin improves speech comprehension in autism. The primary aim of this study was to investigate whether the orientation behaviors toward human sounds are different for neurotypical (NT) adults and adults with ASD and whether oxytocin has an effect on their orientation behaviors toward human sounds. Methods This was a randomized, placebo-controlled, within-subject, crossover design study of intranasal oxytocin versus placebo in 13 NT adults and 16 adults with ASD. Subjects were randomized to 24 IU intranasal oxytocin or placebo on different days, and they were blind to the treatment. The participants then listened passively to human and non-human affective sounds while their skin conductance responses (SCRs) and the changes in peripheral blood vessel constriction were monitored as an indicator of spontaneous orientation. The monitored data were analyzed by a mixed-design ANOVA. Results Oxytocin enhanced the difference between the SCRs to human and non-human sounds in both the NT and ASD groups (F(1,56) = 6.046, p = 0.017). Further correlation coefficient analysis showed significant correlations between this SCR difference and the scores in the autism spectrum quotient ‘attention to detail’ and ‘social skill’ subscales and interpersonal reactivity index and social functioning scale in the ASD group. Oxytocin was well tolerated, and no serious adverse effects were reported. Conclusions The difference in SCRs implies that oxytocin nasal spray may enhance orientation behaviors toward human sounds in the presence of other environmental sounds in both ASD and NT adults. Trial registration UMIN-CTR Clinical Trial, Unique trial number: UMIN000005809 PMID:24576333

  18. Actively controlled shaft seals for aerospace applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.

    1991-01-01

    Actively controlled mechanical seals have recently been developed for industrial use. This study investigates the feasibility of using such seals for aerospace applications. In a noncontacting mechanical seal, the film thickness depends on the geometry of the seal interface. The amount of coning, which is a measure of the radial convergence or divergence of the seal interface, has a primary effect on the film thickness. Active control of the film thickness is established by controlling the coning with a piezoelectric material. A mathematical model has been formulated to predict the performance of an actively controlled mechanical seal.

  19. Variation in the emission rate of sounds in a captive group of false killer whales Pseudorca crassidens during feedings: possible food anticipatory vocal activity?

    NASA Astrophysics Data System (ADS)

    Platto, Sara; Wang, Ding; Wang, Kexiong

    2016-11-01

    This study examines whether a group of captive false killer whales ( Pseudorca crassidens ) showed variations in the vocal rate around feeding times. The high level of motivation to express appetitive behaviors in captive animals may lead them to respond with changes of the behavioral activities during the time prior to food deliveries which are referred to as food anticipatory activity. False killer whales at Qingdao Polar Ocean World (Qingdao, China) showed significant variations of the rates of both the total sounds and sound classes (whistles, clicks, and burst pulses) around feedings. Precisely, from the Transition interval that recorded the lowest vocalization rate (3.40 s/m/d), the whales increased their acoustic emissions upon trainers' arrival (13.08 s/m/d). The high rate was maintained or intensified throughout the food delivery (25.12 s/m/d), and then reduced immediately after the animals were fed (9.91 s/m/d). These changes in the false killer whales sound production rates around feeding times supports the hypothesis of the presence of a food anticipatory vocal activity. Although sound rates may not give detailed information regarding referential aspects of the animal communication it might still shed light about the arousal levels of the individuals during different social or environmental conditions. Further experiments should be performed to assess if variations of the time of feeding routines may affect the vocal activity of cetaceans in captivity as well as their welfare.

  20. Variation in the emission rate of sounds in a captive group of false killer whales Pseudorca crassidens during feedings: possible food anticipatory vocal activity?

    NASA Astrophysics Data System (ADS)

    Platto, Sara; Wang, Ding; Wang, Kexiong

    2015-11-01

    This study examines whether a group of captive false killer whales (Pseudorca crassidens ) showed variations in the vocal rate around feeding times. The high level of motivation to express appetitive behaviors in captive animals may lead them to respond with changes of the behavioral activities during the time prior to food deliveries which are referred to as food anticipatory activity. False killer whales at Qingdao Polar Ocean World (Qingdao, China) showed significant variations of the rates of both the total sounds and sound classes (whistles, clicks, and burst pulses) around feedings. Precisely, from the Transition interval that recorded the lowest vocalization rate (3.40 s/m/d), the whales increased their acoustic emissions upon trainers' arrival (13.08 s/m/d). The high rate was maintained or intensified throughout the food delivery (25.12 s/m/d), and then reduced immediately after the animals were fed (9.91 s/m/d). These changes in the false killer whales sound production rates around feeding times supports the hypothesis of the presence of a food anticipatory vocal activity. Although sound rates may not give detailed information regarding referential aspects of the animal communication it might still shed light about the arousal levels of the individuals during different social or environmental conditions. Further experiments should be performed to assess if variations of the time of feeding routines may affect the vocal activity of cetaceans in captivity as well as their welfare.

  1. Potential Subjective Effectiveness of Active Interior Noise Control in Propeller Airplanes

    NASA Technical Reports Server (NTRS)

    Powell, Clemans A.; Sullivan, Brenda M.

    2000-01-01

    Active noise control technology offers the potential for weight-efficient aircraft interior noise reduction, particularly for propeller aircraft. However, there is little information on how passengers respond to this type of interior noise control. This paper presents results of two experiments that use sound quality engineering practices to determine the subjective effectiveness of hypothetical active noise control (ANC) systems in a range of propeller aircraft. The two experiments differed by the type of judgments made by the subjects: pair comparisons based on preference in the first and numerical category scaling of noisiness in the second. Although the results of the two experiments were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference. The reductions in subjective response due to the ANC conditions were predicted with reasonable accuracy by reductions in measured loudness level. Inclusion of corrections for the sound quality characteristics of tonality and fluctuation strength in multiple regression models improved the prediction of the ANC effects.

  2. Active control: an investigation method for combustion instabilities

    NASA Astrophysics Data System (ADS)

    Poinsot, T.; Yip, B.; Veynante, D.; Trouvé, A.; Samaniego, J. M.; Candel, S.

    1992-07-01

    Closed-loop active control methods and their application to combustion instabilities are discussed. In these methods the instability development is impeded with a feedback control loop: the signal provided by a sensor monitoring the flame or pressure oscillations is processed and sent back to actuators mounted on the combustor or on the feeding system. Different active control systems tested on a non-premixed multiple-flame turbulent combustor are described. These systems can suppress all unstable plane modes of oscillation (i.e. low frequency modes). The active instability control (AIC) also constitutes an original and powerful technique for studies of mechanisms leading to instability or resulting from the instability. Two basic applications of this kind are described. In the first case the flame is initially controlled with AIC, the feedback loop is then switched off and the growth of the instability is analysed through high speed Schlieren cinematography and simultaneous sound pressure and reaction rate measurements. Three phases are identified during th growth of the oscillations: (1) a linear phase where acoustic waves induce a flapping motion of the flame sheets without interaction between sheets, (2) a modulation phase, where flame sheets interact randomly and (3) a nonlinear phase where the flame sheets are broken and a limit cycle is reached. In the second case we investigate different types of flame extinctions associated with combustion instability. It is shown that pressure oscillations may lead to partial or total extinctions. Extinctions occur in various forms but usually follow a rapid growth of pressure oscillations. The flame is extinguished during the modulation phase observed in the initiation experiments. In these studies devoted to transient instability phenomena, the control system constitutes a unique investigation tool because it is difficult to obtain the same information by other means. Implications for modelling and prediction of

  3. Exploring Noise: Sound Pollution.

    ERIC Educational Resources Information Center

    Rillo, Thomas J.

    1980-01-01

    This article is the last of a three-part series dealing with sound measurement, effects, pollution, and indoor/door learning activities. This section focuses on outdoor activities and equipment that students can make to assist them in data collection. (Author/SA)

  4. Effects of multiple congruent cues on concurrent sound segregation during passive and active listening: an event-related potential (ERP) study.

    PubMed

    Kocsis, Zsuzsanna; Winkler, István; Szalárdy, Orsolya; Bendixen, Alexandra

    2014-07-01

    In two experiments, we assessed the effects of combining different cues of concurrent sound segregation on the object-related negativity (ORN) and the P400 event-related potential components. Participants were presented with sequences of complex tones, half of which contained some manipulation: one or two harmonic partials were mistuned, delayed, or presented from a different location than the rest. In separate conditions, one, two, or three of these manipulations were combined. Participants watched a silent movie (passive listening) or reported after each tone whether they perceived one or two concurrent sounds (active listening). ORN was found in almost all conditions except for location difference alone during passive listening. Combining several cues or manipulating more than one partial consistently led to sub-additive effects on the ORN amplitude. These results support the view that ORN reflects a combined, feature-unspecific assessment of the auditory system regarding the contribution of two sources to the incoming sound. PMID:24816158

  5. Hearing silences: human auditory processing relies on preactivation of sound-specific brain activity patterns.

    PubMed

    SanMiguel, Iria; Widmann, Andreas; Bendixen, Alexandra; Trujillo-Barreto, Nelson; Schröger, Erich

    2013-05-15

    The remarkable capabilities displayed by humans in making sense of an overwhelming amount of sensory information cannot be explained easily if perception is viewed as a passive process. Current theoretical and computational models assume that to achieve meaningful and coherent perception, the human brain must anticipate upcoming stimulation. But how are upcoming stimuli predicted in the brain? We unmasked the neural representation of a prediction by omitting the predicted sensory input. Electrophysiological brain signals showed that when a clear prediction can be formulated, the brain activates a template of its response to the predicted stimulus before it arrives to our senses.

  6. Geophysical Sounding

    NASA Astrophysics Data System (ADS)

    Blake, E.

    1998-01-01

    Of the many geophysical remote-sensing techniques available today, a few are suitable for the water ice-rich, layered material expected at the north martian ice cap. Radio echo sounding has been used for several decades to determine ice thickness and internal structure. Selection of operating frequency is a tradeoff between signal attenuation (which typically increases with frequency and ice temperature) and resolution (which is proportional to wavelength). Antenna configuration and size will be additional considerations for a mission to Mars. Several configurations for ice-penetrating radar systems are discussed: these include orbiter-borne sounders, sounding antennas trailed by balloons and penetrators, and lander-borne systems. Lander-borne systems could include short-wave systems capable of resolving fine structure and layering in the upper meters beneath the lander. Spread-spectrum and deconvolution techniques can be used to increase the depth capability of a radar system. If soundings over several locations are available (e.g., with balloons, rovers, or panning short-wave systems), then it will be easier to resolve internal layering, variations in basal reflection coefficient (from which material properties may be inferred), and the geometry of nonhorizontal features. Sonic sounding has a long history in oil and gas exploration. It is, however, unlikely that large explosive charges, or even swept-frequency techniques such as Vibroseis, would be suitable for a Polar lander -- these systems are capable of penetrating several kilometers of material at frequencies of 10-200 Hz, but the energy required to generate the sound waves is large and potentially destructive. The use of audio-frequency and ultrasonic sound generated by piezoelectric crystals is discussed as a possible method to explore layering and fine features in the upper meters of the ice cap. Appropriate choice of transducer(s) will permit operation over a range of fixed or modulated frequencies

  7. Active vibration control of lightweight floor systems

    NASA Astrophysics Data System (ADS)

    Baader, J.; Fontana, M.

    2016-04-01

    Wide-span and lightweight floors are often prone to structural vibrations due to their low resonance frequency and poor material damping. Their dynamic behaviour can be improved using passive, semi-active or active vibration control devices. The following article proposes a novel method for the controller synthesis for active vibration control. An existing passive TMD (tuned mass damper) is modelled and equipped with an actuator in order to provide more efficient damping. Using an iterative optimization approach under constraints, an optimal controller is found which minimizes a quadratic cost function in frequency domain. A simulation of an existing test bench shows that the active vibration control device is able to provide increased damping compared to the passive TMD.

  8. Temporally Unpredictable Sounds Exert a Context-Dependent Influence on Evaluation of Unrelated Images

    PubMed Central

    Bach, Dominik R.; Seifritz, Erich; Dolan, Raymond J.

    2015-01-01

    Temporally unpredictable stimuli influence murine and human behaviour, as previously demonstrated for sequences of simple sounds with regular or irregular onset. It is unknown whether this influence is mediated by an evaluation of the unpredictable sound sequences themselves, or by an interaction with task context. Here, we find that humans evaluate unrelated neutral pictures as more negative when these are presented together with a temporally unpredictable sound sequence, compared to a predictable sequence. The same is observed for evaluation of neutral, angry and fearful face photographs. Control experiments suggest this effect is specific to interspersed presentation of negative and neutral visual stimuli. Unpredictable sounds presented on their own were evaluated as more activating, but not more aversive, and were preferred over predictable sounds. When presented alone, these sound sequences also did not elicit tonic autonomic arousal or negative mood change. We discuss how these findings might account for previous data on the effects of unpredictable sounds, in humans and rodents. PMID:26098105

  9. Reliable and Affordable Control Systems Active Combustor Pattern Factor Control

    NASA Technical Reports Server (NTRS)

    McCarty, Bob; Tomondi, Chris; McGinley, Ray

    2004-01-01

    Active, closed-loop control of combustor pattern factor is a cooperative effort between Honeywell (formerly AlliedSignal) Engines and Systems and the NASA Glenn Research Center to reduce emissions and turbine-stator vane temperature variations, thereby enhancing engine performance and life, and reducing direct operating costs. Total fuel flow supplied to the engine is established by the speed/power control, but the distribution to individual atomizers will be controlled by the Active Combustor Pattern Factor Control (ACPFC). This system consist of three major components: multiple, thin-film sensors located on the turbine-stator vanes; fuel-flow modulators for individual atomizers; and control logic and algorithms within the electronic control.

  10. Generating the sounds of silence

    SciTech Connect

    O'Conner, L.

    1994-04-01

    This article describes how digital-signal processors and repetitive- and random-noise algorithms have been linked to spur production of active control mufflers and headsets. Active and passive quieting systems are being developed to reduce noise from aircraft and other sources. High-level noise not only affects hearing, it can drive up blood pressure, disrupt sleep, and compromise the ability to work and learn. Although noise gets less attention than more conspicuous pollutants, public awareness over the unhealthy repercussions of loud noise is higher than ever. Recognizing public sensitivity over this topic, companies have begun producing active noise-control systems to reduce low-frequency sound--usually lower than 600 Hz--that often escapes established methods of passive quieting.

  11. Sound Solutions

    ERIC Educational Resources Information Center

    Starkman, Neal

    2007-01-01

    Poor classroom acoustics are impairing students' hearing and their ability to learn. However, technology has come up with a solution: tools that focus voices in a way that minimizes intrusive ambient noise and gets to the intended receiver--not merely amplifying the sound, but also clarifying and directing it. One provider of classroom audio…

  12. Sound Naming in Neurodegenerative Disease

    PubMed Central

    Chow, Maggie L; Brambati, Simona M; Gorno-Tempini, Maria Luisa; Miller, Bruce L; Johnson, Julene K

    2010-01-01

    Modern cognitive neuroscientific theories and empirical evidence suggest that brain structures involved in movement may be related to action-related semantic knowledge. To test this hypothesis, we examined the naming of environmental sounds in patients with corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP), two neurodegenerative diseases associated with cognitive and motor deficits. Subjects were presented with 56 environmental sounds: 28 of objects that required manipulation when producing the sound, and 28 that required no manipulation. Subjects were asked to provide the name of the object that produced the sound and also complete a sound-picture matching condition. Subjects included 33 individuals from four groups: CBD/PSP, Alzheimer disease, frontotemporal dementia, and normal controls. We hypothesized that CBD/PSP patients would exhibit impaired naming performance compared with controls, but the impairment would be most apparent when naming sounds associated with actions. We also explored neural correlates of naming environmental sounds using voxel-based morphometry (VBM) of brain MRI. As expected, CBD/PSP patients scored lower on environmental sounds naming (p<0.007) compared with the controls. In particular, the CBD/PSP patients scored the lowest when naming sounds of manipulable objects (p<0.05), but did not show deficits in naming sounds of non-manipulable objects. VBM analysis across all groups showed that performance in naming sounds of manipulable objects correlated with atrophy in the left premotor region, extending from area 6 to the middle and superior frontal gyrus. These results indicate an association between impairment in the retrieval of action-related names and the motor system, and suggest that difficulty in naming manipulable sounds may be related to atrophy in the premotor cortex. Our results support the hypothesis that retrieval of action-related semantic knowledge involves motor regions in the brain. PMID:20089342

  13. Active tectonics of the Seattle fault and central Puget sound, Washington - Implications for earthquake hazards

    USGS Publications Warehouse

    Johnson, S.Y.; Dadisman, S.V.; Childs, J. R.; Stanley, W.D.

    1999-01-01

    We use an extensive network of marine high-resolution and conventional industry seismic-reflection data to constrain the location, shallow structure, and displacement rates of the Seattle fault zone and crosscutting high-angle faults in the Puget Lowland of western Washington. Analysis of seismic profiles extending 50 km across the Puget Lowland from Lake Washington to Hood Canal indicates that the west-trending Seattle fault comprises a broad (4-6 km) zone of three or more south-dipping reverse faults. Quaternary sediment has been folded and faulted along all faults in the zone but is clearly most pronounced along fault A, the northernmost fault, which forms the boundary between the Seattle uplift and Seattle basin. Analysis of growth strata deposited across fault A indicate minimum Quaternary slip rates of about 0.6 mm/yr. Slip rates across the entire zone are estimated to be 0.7-1.1 mm/yr. The Seattle fault is cut into two main segments by an active, north-trending, high-angle, strike-slip fault zone with cumulative dextral displacement of about 2.4 km. Faults in this zone truncate and warp reflections in Tertiary and Quaternary strata and locally coincide with bathymetric lineaments. Cumulative slip rates on these faults may exceed 0.2 mm/yr. Assuming no other crosscutting faults, this north-trending fault zone divides the Seattle fault into 30-40-km-long western and eastern segments. Although this geometry could limit the area ruptured in some Seattle fault earthquakes, a large event ca. A.D. 900 appears to have involved both segments. Regional seismic-hazard assessments must (1) incorporate new information on fault length, geometry, and displacement rates on the Seattle fault, and (2) consider the hazard presented by the previously unrecognized, north-trending fault zone.

  14. Active control of buildings during earthquakes

    NASA Technical Reports Server (NTRS)

    Vance, Vicki L.

    1993-01-01

    The objective of this report is to provide an overview of the different types of control systems used in buildings, to discuss the problems associated with current active control mechanisms, and to show the cost-effectiveness of applying active control to buildings. In addition, a small case study investigates the feasibility and benefits of using embedded actuators in buildings. Use of embedded actuators could solve many of the current problems associated with active control by providing a wider bandwidth of control, quicker speed of response, increased reliability and reduced power requirement. Though embedded actuators have not been developed for buildings, they have previously been used in space structures. Many similarities exist between large civil and aerospace structures indicating that direct transfer of concepts between the two disciplines may be possible. In particular, much of the Controls-Structures Interaction (CSI) technology currently being developed could be beneficially applied to civil structures. While several buildings with active control systems have been constructed in Japan, additional research and experimental verification are necessary before active control systems become widely accepted and implemented.

  15. A Lightweight Loudspeaker for Aircraft Communications and Active Noise Control

    NASA Technical Reports Server (NTRS)

    Warnaka, Glenn E.; Kleinle, Mark; Tsangaris, Parry; Oslac, Michael J.; Moskow, Harry J.

    1992-01-01

    A series of new, lightweight loudspeakers for use on commercial aircraft has been developed. The loudspeakers use NdFeB magnets and aluminum alloy frames to reduce the weight. The NdFeB magnet is virtually encapsulated by steel in the new speaker designs. Active noise reduction using internal loudspeakers was demonstrated to be effective in 1983. A weight, space, and cost efficient method for creating the active sound attenuating fields is to use the existing cabin loudspeakers for both communication and sound attenuation. This will require some additional loudspeaker design considerations.

  16. The Middeck Active Control Experiment (MACE)

    NASA Technical Reports Server (NTRS)

    Miller, David W.

    1991-01-01

    Viewgraphs on the Middeck Active Control Experiment (MACE) are presented. Topics covered include: science program objectives and rationale; science requirements; capturing the essential physics; science development approach; development model hardware; development model test plan; and flight hardware and operations.

  17. Active control of turbomachine discrete tones

    NASA Astrophysics Data System (ADS)

    Fleeter, Sanford

    This paper was directed at active control of discrete frequency noise generated by subsonic blade rows through cancellation of the blade row interaction generated propagating acoustic waves. First discrete frequency noise generated by a rotor and stator in a duct was analyzed to determine the propagating acoustic pressure waves. Then a mathematical model was developed to analyze and predict the active control of discrete frequency noise generated by subsonic blade rows through cancellation of the propagating acoustic waves, accomplished by utilizing oscillating airfoil surfaces to generate additional control propagating pressure waves. These control waves interact with the propagating acoustic waves, thereby, in principle, canceling the acoustic waves and thus, the far field discrete frequency tones. This model was then applied to a fan exit guide vane to investigate active airfoil surface techniques for control of the propagating acoustic waves, and thus the far field discrete frequency tones, generated by blade row interactions.

  18. Active load control techniques for wind turbines.

    SciTech Connect

    van Dam, C.P.; Berg, Dale E.; Johnson, Scott J.

    2008-07-01

    This report provides an overview on the current state of wind turbine control and introduces a number of active techniques that could be potentially used for control of wind turbine blades. The focus is on research regarding active flow control (AFC) as it applies to wind turbine performance and loads. The techniques and concepts described here are often described as 'smart structures' or 'smart rotor control'. This field is rapidly growing and there are numerous concepts currently being investigated around the world; some concepts already are focused on the wind energy industry and others are intended for use in other fields, but have the potential for wind turbine control. An AFC system can be broken into three categories: controls and sensors, actuators and devices, and the flow phenomena. This report focuses on the research involved with the actuators and devices and the generated flow phenomena caused by each device.

  19. Student Activity Funds: Procedures and Controls.

    ERIC Educational Resources Information Center

    Cuzzetto, Charles E.

    2000-01-01

    An effective internal-control system can help school business administrators meet the challenges of accounting for student activity funds. Such a system should include appropriate policies and procedures, identification of key control points, self-assessments, audit trails, and internal and external audits. (MLH)

  20. Mission control activity during STS-61 EVA

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Flight controller Susan P. Rainwater observes as two astronauts work through a lengthy period of extravehicular activity (EVA) in the cargo bay of the Earth-looking Space Shuttle Endeavour. Rainwater's EVA console was one of Mission Control's busiest during this eleven-day Hubble Space Telescope (HST) servicing mission in Earth orbit.

  1. Actively Controlled Magnetic Vibration-Isolation System

    NASA Technical Reports Server (NTRS)

    Grodsinky, Carlos M.; Logsdon, Kirk A.; Wbomski, Joseph F.; Brown, Gerald V.

    1993-01-01

    Prototype magnetic suspension system with active control isolates object from vibrations in all six degrees of freedom at frequencies as low as 0.01 Hz. Designed specifically to protect instruments aboard spacecraft by suppressing vibrations to microgravity levels; basic control approach used for such terrestrial uses as suppression of shocks and other vibrations in trucks and railroad cars.

  2. Hearing-aid automatic gain control adapting to two sound sources in the environment, using three time constants

    NASA Astrophysics Data System (ADS)

    Nordqvist, Peter; Leijon, Arne

    2004-11-01

    A hearing aid AGC algorithm is presented that uses a richer representation of the sound environment than previous algorithms. The proposed algorithm is designed to (1) adapt slowly (in approximately 10 s) between different listening environments, e.g., when the user leaves a single talker lecture for a multi-babble coffee-break; (2) switch rapidly (about 100 ms) between different dominant sound sources within one listening situation, such as the change from the user's own voice to a distant speaker's voice in a quiet conference room; (3) instantly reduce gain for strong transient sounds and then quickly return to the previous gain setting; and (4) not change the gain in silent pauses but instead keep the gain setting of the previous sound source. An acoustic evaluation showed that the algorithm worked as intended. The algorithm was evaluated together with a reference algorithm in a pilot field test. When evaluated by nine users in a set of speech recognition tests, the algorithm showed similar results to the reference algorithm. .

  3. [Septal Activation and Control of Limbic Structures].

    PubMed

    Fedotova, I R; Frolov, A A

    2015-01-01

    Coherent activation of limbic system structures as the main function of theta-rhythm is widely discussed in the literature. However until now does not exist the common view on its generation in these brain structures. The model of septal theta-rhythmic activation and control of limbic structures is suggested basing on the literature and own experimental data.

  4. Auditory Evaluation of Sound Signals Radiated by a Vibrating Surface

    NASA Astrophysics Data System (ADS)

    MEUNIER, S.; HABAULT, D.; CANÉVET, G.

    2001-11-01

    This paper presents a combination of vibroacoustic and psychoacoustic studies of sounds radiated by a vibrating structure. The calculated sound field is the sound pressure radiated by a baffled thin-plate structure immersed in a fluid, on the surface of which the acceleration is given. Various configurations are selected for the time and space functions of the acceleration variable, each configuration leading to a particular acoustic signal (a low-frequency tone complex in our case). These signals are then transformed into sound files, which are used as test signals in psychoacoustic experiments for assessing their perceptual attributes and quality. Two experiments were run. In the first one, the unpleasantness of a series of signals at different levels was measured by direct estimation and compared with their calculated loudness and sharpness using Zwicker's model. The same measurements were repeated with the signals set to the same maximum amplitude. In the second experiment, the pleasantness of another series of sounds at equal loudness was measured, as well as dissimilarity and preference on pairs of these sounds. An MDS analysis was run to extract auditory attributes that could account for the perceived differences between sounds and correlate with the estimated pleasantness. The results from the first experiment show that pleasantness is always highly (and negatively) correlated with loudness. The same holds for sharpness, when sounds are played at the same maximum amplitude. The second experiment shows that the perceptual attributes revealed by the MDS analysis are related to pitch and timbre, the latter being highly correlated with pleasantness. Overall, this study confirms the interest of extending vibroacoustic studies to a more complete “psychomechanical” investigation of the whole process of sound generation. It is suggested that such investigations may apply to product sound quality and to active or passive noise control, by providing

  5. Proceedings, inter-noise 84 - international cooperation for noise control. 2 Vols

    SciTech Connect

    Maling, G.C. Jr.

    1984-01-01

    A total of 199 papers were presented on noise control engineering, especially in the areas of community noise control, sound intensity, noise emission sources, active sound attenuation and noise reduction by barriers. 4 papers have been abstracted separately.

  6. Crossmodal enhancement of visual orientation discrimination by looming sounds requires functional activation of primary visual areas: a case study.

    PubMed

    Cecere, Roberto; Romei, Vincenzo; Bertini, Caterina; Làdavas, Elisabetta

    2014-04-01

    Approaching or looming sounds are salient, potentially threatening stimuli with particular impact on visual processing. The early crossmodal effects by looming sounds (Romei, Murray, Cappe, & Thut, 2009) and their selective impact on visual orientation discrimination (Leo, Romei, Freeman, Ladavas, & Driver, 2011) suggest that these multisensory interactions may take place already within low-level visual cortices. To investigate this hypothesis, we tested a patient (SDV) with bilateral occipital lesion and spared residual portions of V1/V2. Accordingly, SDV׳s visual perimetry revealed blindness of the central visual field with some residual peripheral vision. In two experiments we tested for the influence of looming vs. receding and stationary sounds on SDV׳s line orientation discrimination (orientation discrimination experiment) and visual detection abilities (detection experiment) in the preserved or blind portions of the visual field, corresponding to spared and lesioned areas of V1, respectively. In the visual orientation discrimination experiment we found that SDV visual orientation sensitivity significantly improved for visual targets paired with looming sounds but only for lines presented in the partially preserved visual field. In the visual detection experiment, where SDV was required to simply detect the same stimuli presented in the orientation discrimination experiment, a generalised sound-induced visual improvement both in the intact and in blind portion of the visual field was observed. These results provide direct evidence that early visual areas are critically involved in crossmodal modulation of visual orientation sensitivity by looming sounds. Thus, a lesion in V1 prevents the enhancement of visual orientation sensitivity. In contrast, the same lesion does not prevent the visual detection enhancement by a sound, probably due to alternative visual pathways (e.g. retino-colliculo-extrastriate) which are usually spared in these patients and able to

  7. Exploring Sound with Insects

    ERIC Educational Resources Information Center

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  8. Sounds Like Fun.

    ERIC Educational Resources Information Center

    Lucas, Linda M.

    1991-01-01

    Presents hands-on science activities that help students learn the concepts of hearing and sound while allowing students to practice science process skills. Students investigate the use of alternative phonograph speakers and needles and apply the knowledge learned to the construction of one-string banjos. (MDH)

  9. Control of nucleus accumbens activity with neurofeedback.

    PubMed

    Greer, Stephanie M; Trujillo, Andrew J; Glover, Gary H; Knutson, Brian

    2014-08-01

    The nucleus accumbens (NAcc) plays critical roles in healthy motivation and learning, as well as in psychiatric disorders (including schizophrenia and attention deficit hyperactivity disorder). Thus, techniques that confer control of NAcc activity might inspire new therapeutic interventions. By providing second-to-second temporal resolution of activity in small subcortical regions, functional magnetic resonance imaging (fMRI) can resolve online changes in NAcc activity, which can then be presented as "neurofeedback." In an fMRI-based neurofeedback experiment designed to elicit NAcc activity, we found that subjects could increase their own NAcc activity, and that display of neurofeedback significantly enhanced their ability to do so. Subjects were not as capable of decreasing their NAcc activity, however, and enhanced control did not persist after subsequent removal of neurofeedback. Further analyses suggested that individuals who recruited positive aroused affect were better able to increase NAcc activity in response to neurofeedback, and that NAcc neurofeedback also elicited functionally correlated activity in the medial prefrontal cortex. Together, these findings suggest that humans can modulate their own NAcc activity and that fMRI-based neurofeedback may augment their efforts. The observed association between positive arousal and effective NAcc control further supports an anticipatory affect account of NAcc function.

  10. Control of nucleus accumbens activity with neurofeedback

    PubMed Central

    Greer, Stephanie M.; Trujillo, Andrew J.; Glover, Gary H.; Knutson, Brian

    2014-01-01

    The nucleus accumbens (NAcc) plays critical roles in healthy motivation and learning, as well as in psychiatric disorders (including schizophrenia and attention deficit hyperactivity disorder). Thus, techniques that confer control of NAcc activity might inspire new therapeutic interventions. By providing second-to-second temporal resolution of activity in small subcortical regions, functional magnetic resonance imaging (fMRI) can resolve online changes in NAcc activity, which can then be presented as “neurofeedback.” In an fMRI-based neurofeedback experiment designed to elicit NAcc activity, we found that subjects could increase their own NAcc activity, and that display of neurofeedback significantly enhanced their ability to do so. Subjects were not as capable of decreasing their NAcc activity, however, and enhanced control did not persist after subsequent removal of neurofeedback. Further analyses suggested that individuals who recruited positive arousal affect were better able to increase NAcc activity in response to neurofeedback, and that NAcc neurofeedback also elicited functionally correlated activity in the medial prefrontal cortex. Together, these findings suggest that humans can modulate their own NAcc activity and that fMRI-based neurofeedback may augment their efforts. The observed association between positive arousal and effective NAcc control further supports an anticipatory affect account of NAcc function. PMID:24705203

  11. A Randomized Controlled Trial on The Beneficial Effects of Training Letter-Speech Sound Integration on Reading Fluency in Children with Dyslexia

    PubMed Central

    Fraga González, Gorka; Žarić, Gojko; Tijms, Jurgen; Bonte, Milene; van der Molen, Maurits W.

    2015-01-01

    A recent account of dyslexia assumes that a failure to develop automated letter-speech sound integration might be responsible for the observed lack of reading fluency. This study uses a pre-test-training-post-test design to evaluate the effects of a training program based on letter-speech sound associations with a special focus on gains in reading fluency. A sample of 44 children with dyslexia and 23 typical readers, aged 8 to 9, was recruited. Children with dyslexia were randomly allocated to either the training program group (n = 23) or a waiting-list control group (n = 21). The training intensively focused on letter-speech sound mapping and consisted of 34 individual sessions of 45 minutes over a five month period. The children with dyslexia showed substantial reading gains for the main word reading and spelling measures after training, improving at a faster rate than typical readers and waiting-list controls. The results are interpreted within the conceptual framework assuming a multisensory integration deficit as the most proximal cause of dysfluent reading in dyslexia. Trial Registration: ISRCTN register ISRCTN12783279 PMID:26629707

  12. Active vibration control of civil structures

    SciTech Connect

    Farrar, C.; Baker, W.; Fales, J.; Shevitz, D.

    1996-11-01

    This is a final report of a one year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Active vibration control (AVC) of structural and mechanical systems is one of the rapidly advancing areas of engineering research. The multifaceted nature of AVC covers many disciplines, such as sensors and instrumentation, numerical modeling, experimental mechanics, and advanced power systems. This work encompassed a review of the literature on active control of structures focusing both on active control hardware and on control algorithms, a design of an isolation systems using magneto-rheological fluid-filled (MRF) dampers and numerical simulations to study the enhanced vibration mitigation effects of this technology.

  13. Vector control activities: Fiscal Year, 1986

    SciTech Connect

    Not Available

    1987-04-01

    The program is divided into two major components - operations and support studies. The support studies are designed to improve the operational effectiveness and efficiency of the control program and to identify other vector control problems requiring TVA attention and study. Nonchemical methods of control are emphasized and are supplemented with chemical measures as needed. TVA also cooperates with various concerned municipalities in identifying blood-sucking arthropod pest problems and demonstrating control techniques useful in establishing abatement programs, and provides technical assistance to other TVA programs and organizations. The program also helps Land Between The Lakes (LBL) plan and conduct vector control operations and tick control research. Specific program control activities and support studies are discussed.

  14. GPS Sounding Rocket Developments

    NASA Technical Reports Server (NTRS)

    Bull, Barton

    1999-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads several hundred miles in altitude. These missions return a variety of scientific data including; chemical makeup and physical processes taking place In the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft prior to their use in more expensive activities. The NASA Sounding Rocket Program is managed by personnel from Goddard Space Flight Center Wallops Flight Facility (GSFC/WFF) in Virginia. Typically around thirty of these rockets are launched each year, either from established ranges at Wallops Island, Virginia, Poker Flat Research Range, Alaska; White Sands Missile Range, New Mexico or from Canada, Norway and Sweden. Many times launches are conducted from temporary launch ranges in remote parts of the world requi6ng considerable expense to transport and operate tracking radars. An inverse differential GPS system has been developed for Sounding Rocket. This paper addresses the NASA Wallops Island history of GPS Sounding Rocket experience since 1994 and the development of a high accurate and useful system.

  15. High Resolution Geophysical Survey of Western Long Island Sound Offshore New York: An Estuary Floor Shaped by Bottom Currents and Human Activity

    NASA Astrophysics Data System (ADS)

    Vargas, W.; Cormier, M.; McHugh, C.

    2009-05-01

    Western Long Island Sound near metropolitan New York averages 16m in water depth, with a few elongated depression up to 40 m deep. In June 2006, we surveyed the westernmost section of Long island Sound with the R/V HUGH SHARP. Analysis of the high-resolution multibeam bathymetric data collected during that survey reveals a series of sedimentary features that are consistent with a net westward direction of bottom currents. These features include: (1) Large sedimentary waves spaced ab out 100 m west of two km-scale features outcropping through the sediments; (2) Prominent sediment drifts or scour marks west of numerous shipwrecks and bouldery outcrops; (3) Series of subtle, sub-parallel sedimentary furrows aligned in a general EW direction along the north slope of the surveyed area (similar features have been documented in north- central Long Island Sound - (Poppe et al., J. Coastal Res. 2002). The lack of short wavelength sedimentary waves is consistent with the known muddy substrate and weak bottom currents (<10 cm/s) documented in western Long Island Sound. Fields of pockmarks affecting areas of gas-charged sediments may indicate localized, active venting of fluids and/or gas. The high-resolution bathymetry also highlights numerous anthropogenic disturbances such as pipelines, cables, shipwrecks, anchor drag marks, and dredge spoils.

  16. Implementation of active magnetic bearing digital controller

    NASA Astrophysics Data System (ADS)

    Liu, Hu; Fang, Jiancheng; Liu, Gang

    2006-11-01

    An active magnetic bearing digital controller is presented. This system is based on high-speed floating-point digital signal processor (DSP) and field programmable gate array (FPGA). The active vibration control algorithms are coded in C language where is possible to reduce the probabilities of software errors occurring and to reduce the debugging time for those errors and are executed by the high-speed floating-point DSP. This paper describes the implementation of the controller. The proposed digital control system can meet the requirement of enough throughput which is difficult using a single fixed-pointing DSP, realize integration of magnetic bearings controller and have the merits of easily to maintain and be applied in other magnetic bearings systems. The system has been applied successfully in several actual magnetic bearings systems at Beijing University of Aeronautics and Astronautics and the experimental results verify its feasibility.

  17. CFD Modeling for Active Flow Control

    NASA Technical Reports Server (NTRS)

    Buning, Pieter G.

    2001-01-01

    This presentation describes current work under UEET Active Flow Control CFD Research Tool Development. The goal of this work is to develop computational tools for inlet active flow control design. This year s objectives were to perform CFD simulations of fully gridded vane vortex generators, micro-vortex genera- tors, and synthetic jets, and to compare flowfield results with wind tunnel tests of simple geometries with flow control devices. Comparisons are shown for a single micro-vortex generator on a flat plate, and for flow over an expansion ramp with sidewall effects. Vortex core location, pressure gradient and oil flow patterns are compared between experiment and computation. This work lays the groundwork for evaluating simplified modeling of arrays of devices, and provides the opportunity to test simple flow control device/sensor/ control loop interaction.

  18. Active vibration control in microgravity environment

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.

    1987-01-01

    The low gravity environment of the space station is suitable for experiments or manufacturing processes which require near zero gravity. An experiment was fabricated to test the validity of the active control process and to verify the flow and control parameters identified in a theoretical model. Zero gravity is approximated in the horizontal plane using a low friction air bearing table. An analog control system was designed to activate calibrated air jets when displacement of the test mass is sensed. The experiment demonstrates that an air jet control system introduces an effective damping factor to control oscillatory response. The amount of damping as well as the flow parameters, such as pressure drop across the valve and flow rate of air, are verified by the analytical model.

  19. Active control of robot manipulator compliance

    NASA Technical Reports Server (NTRS)

    Nguyen, C. C.; Pooran, F. J.

    1986-01-01

    Work performed at Catholic University on the research grant entitled Active Control of Robot Manipulator Compliance, supported by NASA/Goddard space Flight Center during the period of May 15th, 1986 to November 15th, 1986 is described. The modelling of the two-degree-of-freedom robot is first presented. Then the complete system including the robot and the hybrid controller is simulated on an IBM-XT Personal Computer. Simulation results showed that proper adjustments of controller gains enable the robot to perform successful operations. Further research should focus on developing a guideline for the controller gain design to achieve system stability.

  20. Simulation studies for multichannel active vibration control

    NASA Astrophysics Data System (ADS)

    Prakash, Shashikala; Balasubramaniam, R.; Praseetha, K. K.

    2003-10-01

    Traditional approach to vibration control uses passive techniques, which are relatively large, costly and ineffective at low frequencies. Active Vibration Control (AVC) is used to overcome these problems & in AVC additional sources (secondary) are used to cancel vibration from primary source based on the principle of superposition theorem Since the characteristics of the vibration source and environment are time varying, the AVC system must be adaptive. Adaptive systems have the ability to track time varying disturbances and provide optimal control over a much broader range of conditions than conventional fixed control systems. In multi channel AVC vibration fields in large dimensions are controlled & is more complicated. Therefore to actively control low frequency vibrations on large structures, multi channel AVC requires a control system that uses multiple secondary sources to control the vibration field simultaneously at multiple error sensor locations. The error criterion that can be directly measured is the sum of squares of outputs of number of sensors. The adaptive algorithm is designed to minimize this & the algorithm implemented is the "Multiple error LMS algorithm." The best known applications of multiple channel FXLMS algorithm is in real time AVC and system identification. More wider applications are in the control of propeller induced noise in flight cabin interiors. In the present paper the results of simulation studies carried out in MATLAB as well as on TMS320C32 DSP processor will be brought out for a two-channel case.

  1. Active control of buckling of flexible beams

    NASA Technical Reports Server (NTRS)

    Baz, A.; Tampe, L.

    1989-01-01

    The feasibility of using the rapidly growing technology of the shape memory alloys actuators in actively controlling the buckling of large flexible structures is investigated. The need for such buckling control systems is becoming inevitable as the design trends of large space structures have resulted in the use of structural members that are long, slender, and very flexible. In addition, as these truss members are subjected mainly to longitudinal loading they become susceptible to structural instabilities due to buckling. Proper control of such instabilities is essential to the effective performance of the structures as stable platforms for communication and observation. Mathematical models are presented that simulate the dynamic characteristics of the shape memory actuator, the compressive structural members, and the associated active control system. A closed-loop computer-controlled system is designed, based on the developed mathematical models, and implemented to control the buckling of simple beams. The performance of the computer-controlled system is evaluated experimentally and compared with the theoretical predictions to validate the developed models. The obtained results emphasize the importance of buckling control and suggest the potential of the shape memory actuators as attractive means for controlling structural deformation in a simple and reliable way.

  2. Actively controlled shaft seals for aerospace applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.

    1994-01-01

    This study experimentally investigates an actively controlled mechanical seal for aerospace applications. The seal of interest is a gas seal, which is considerably more compact than previous actively controlled mechanical seals that were developed for industrial use. In a mechanical seal, the radial convergence of the seal interface has a primary effect on the film thickness. Active control of the film thickness is established by controlling the radial convergence of the seal interface with piezoelectric actuator. An actively controlled mechanical seal was initially designed and evaluated using a mathematical model. Based on these results, a seal was fabricated and tested under laboratory conditions. The seal was tested with both helium and air, at rotational speeds up to 3770 rad/sec, and at sealed pressures as high as 1.48 x 10(exp 6) Pa. The seal was operated with both manual control and with a closed-loop control system that used either the leakage rate or face temperature as the feedback. The output of the controller was the voltage applied to the piezoelectric actuator. The seal operated successfully for both short term tests (less than one hour) and for longer term tests (four hours) with a closed-loop control system. The leakage rates were typically 5-15 slm (standard liters per minute), and the face temperatures were generally maintained below 100 C. When leakage rate was used as the feedback signal, the setpoint leakage rate was typically maintained within 1 slm. However, larger deviations occurred during sudden changes in sealed pressure. When face temperature was used as the feedback signal, the setpoint face temperature was generally maintained within 3 C, with larger deviations occurring when the sealed pressure changed suddenly.

  3. Assessment and evaluation of noise controls on roof bolting equipment and a method for predicting sound pressure levels in underground coal mining

    NASA Astrophysics Data System (ADS)

    Matetic, Rudy J.

    Over-exposure to noise remains a widespread and serious health hazard in the U.S. mining industries despite 25 years of regulation. Every day, 80% of the nation's miners go to work in an environment where the time weighted average (TWA) noise level exceeds 85 dBA and more than 25% of the miners are exposed to a TWA noise level that exceeds 90 dBA, the permissible exposure limit (PEL). Additionally, MSHA coal noise sample data collected from 2000 to 2002 show that 65% of the equipment whose operators exceeded 100% noise dosage comprise only seven different types of machines; auger miners, bulldozers, continuous miners, front end loaders, roof bolters, shuttle cars (electric), and trucks. In addition, the MSHA data indicate that the roof bolter is third among all the equipment and second among equipment in underground coal whose operators exceed 100% dosage. A research program was implemented to: (1) determine, characterize and to measure sound power levels radiated by a roof bolting machine during differing drilling configurations (thrust, rotational speed, penetration rate, etc.) and utilizing differing types of drilling methods in high compressive strength rock media (>20,000 psi). The research approach characterized the sound power level results from laboratory testing and provided the mining industry with empirical data relative to utilizing differing noise control technologies (drilling configurations and types of drilling methods) in reducing sound power level emissions on a roof bolting machine; (2) distinguish and correlate the empirical data into one, statistically valid, equation, in which, provided the mining industry with a tool to predict overall sound power levels of a roof bolting machine given any type of drilling configuration and drilling method utilized in industry; (3) provided the mining industry with several approaches to predict or determine sound pressure levels in an underground coal mine utilizing laboratory test results from a roof bolting

  4. Vector control activities. Fiscal year, 1982

    SciTech Connect

    Pickard, E.; Cooney, J.C.; McDuff, B.R.

    1983-06-01

    The goal of the TVA Vector Control Program is to protect the public from potential vectors of disease by controlling medically-important arthropod pests that are propagated on TVA lands or waters. In addition, freedom from annoying mosquitoes and other blood-sucking pests permits the development, use, and full enjoyment of the vast recreational opportunities offered by the many miles of freshwater lakes. To attain this goal the program is divided into operations and support studies. The support studies are designed to improve the operational effectiveness and efficiency of the control program and to identify other vector control problems that require TVA attention and study. Specifically, activities concerning water level management of TVA lakes, dewatering projects, plant growth control, drainage and insect control programs are detailed. Further, report is made of post-impoundment surveys, soil sampling studies of Mosquite larvae and ecological mosquito management studies.

  5. Active control of acoustic pressure fields using smart material technologies

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Smith, R. C.

    1993-01-01

    An overview describing the use of piezoceramic patches in reducing noise in a structural acoustics setting is presented. The passive and active contributions due to patches which are bonded to an Euler-Bernoulli beam or thin shell are briefly discussed and the results are incorporated into a 2-D structural acoustics model. In this model, an exterior noise source causes structural vibrations which in turn lead to interior noise as a result of nonlinear fluid/structure coupling mechanism. Interior sound pressure levels are reduced via patches bonded to the flexible boundary (a beam in this case) which generate pure bending moments when an out-of-phase voltage is applied. Well-posedness results for the infinite dimensional system are discussed and a Galerkin scheme for approximating the system dynamics is outlined. Control is implemented by using linear quadratic regulator (LQR) optimal control theory to calculate gains for the linearized system and then feeding these gains back into the nonlinear system of interest. The effectiveness of this strategy for this problem is illustrated in an example.

  6. Actively Controlling Buffet-Induced Excitations

    NASA Technical Reports Server (NTRS)

    Moses, Robert W.; Pototzky, Anthony S.; Henderson, Douglas A.; Galea, Stephen C.; Manokaran, Donald S.; Zimcik, David G.; Wickramasinghe, Viresh; Pitt, Dale M.; Gamble, Michael A.

    2005-01-01

    High performance aircraft, especially those with twin vertical tails, encounter unsteady buffet loads when flying at high angles of attack. These loads result in significant random stresses, which may cause fatigue damage leading to restricted capabilities and availability of the aircraft. An international collaborative research activity among Australia, Canada and the United States, conducted under the auspices of The Technical Cooperation Program (TTCP) contributed resources toward a program that coalesced a broad range of technical knowledge and expertise into a single investigation to demonstrate the enhanced performance and capability of the advanced active BLA control system in preparation for a flight test demonstration. The research team investigated the use of active structural control to alleviate the damaging structural response to these loads by applying advanced directional piezoelectric actuators, the aircraft rudder, switch mode amplifiers, and advanced control strategies on an F/A-18 aircraft empennage. Some results of the full-scale investigation are presented herein.

  7. Active Flow Control Stator With Coanda Surface

    NASA Technical Reports Server (NTRS)

    Guendogdu; Vorreiter; Seume

    2010-01-01

    Active Flow Control increases the permissible aerodynamic loading. Curved surface near the trailing edge ("Coanda surface"): a) increases turning -> higher pressure ratio. b) controls boundary layer separation -> increased surge margin. Objective: Reduce the number of vanes or compressor stages. Constraints: 1. In a real compressor, the vane must still function entirely without blowing. 2. Maintain the flow exit angle of the reference stator despite the resulting increase in stator loading.

  8. Monaural Sound Localization Revisited

    NASA Technical Reports Server (NTRS)

    Wightman, Frederic L.; Kistler, Doris J.

    1997-01-01

    Research reported during the past few decades has revealed the importance for human sound localization of the so-called 'monaural spectral cues.' These cues are the result of the direction-dependent filtering of incoming sound waves accomplished by the pinnae. One point of view about how these cues are extracted places great emphasis on the spectrum of the received sound at each ear individually. This leads to the suggestion that an effective way of studying the influence of these cues is to measure the ability of listeners to localize sounds when one of their ears is plugged. Numerous studies have appeared using this monaural localization paradigm. Three experiments are described here which are intended to clarify the results of the previous monaural localization studies and provide new data on how monaural spectral cues might be processed. Virtual sound sources are used in the experiments in order to manipulate and control the stimuli independently at the two ears. Two of the experiments deal with the consequences of the incomplete monauralization that may have contaminated previous work. The results suggest that even very low sound levels in the occluded ear provide access to interaural localization cues. The presence of these cues complicates the interpretation of the results of nominally monaural localization studies. The third experiment concerns the role of prior knowledge of the source spectrum, which is required if monaural cues are to be useful. The results of this last experiment demonstrate that extraction of monaural spectral cues can be severely disrupted by trial-to-trial fluctuations in the source spectrum. The general conclusion of the experiments is that, while monaural spectral cues are important, the monaural localization paradigm may not be the most appropriate way to study their role.

  9. Offshore Dredger Sounds: Source Levels, Sound Maps, and Risk Assessment.

    PubMed

    de Jong, Christ A F; Ainslie, Michael A; Heinis, Floor; Janmaat, Jeroen

    2016-01-01

    The underwater sound produced during construction of the Port of Rotterdam harbor extension (Maasvlakte 2) was measured, with emphasis on the contribution of the trailing suction hopper dredgers during their various activities: dredging, transport, and discharge of sediment. Measured source levels of the dredgers, estimated source levels of other shipping, and time-dependent position data from a vessel-tracking system were used as input for a propagation model to generate dynamic sound maps. Various scenarios were studied to assess the risk of possible effects of the sound from dredging activities on marine fauna, specifically on porpoises, seals, and fish.

  10. Active disturbance rejection controller for chemical reactor

    SciTech Connect

    Both, Roxana; Dulf, Eva H.; Muresan, Cristina I.

    2015-03-10

    In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However the resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method.

  11. Active Control of Cryogenic Propellants in Space

    NASA Technical Reports Server (NTRS)

    Notardonato, William

    2011-01-01

    A new era of space exploration is being planned. Exploration architectures under consideration require the long term storage of cryogenic propellants in space. This requires development of active control systems to mitigate the effect of heat leak. This work summarizes current state of the art, proposes operational design strategies and presents options for future architectures. Scaling and integration of active systems will be estimated. Ideal long range spacecraft systems will be proposed with Exploration architecture benefits considered.

  12. Seismic active control by neutral networks

    SciTech Connect

    Tang, Yu

    1995-12-31

    A study on the application of artificial neural networks (ANNs) to active structural control under seismic loads is carried out. The structure considered is a single-degree-of-freedom (SDF) system with an active bracing device. The control force is computed by a trained neural network. The feedforward neural network architecture and an adaptive backpropagation training algorithm is used in the study. The neural net is trained to reproduce the function that represents the response-excitation relationship of the SDF system under seismic loads. The input-output training patterns are generated randomly. In the backpropagation training algorithm, the learning rate is determined by ensuring the decrease of the error function at each epoch. The computer program implemented is validated by solving the classification of the XOR problem. Then, the trained ANN is used to compute the control force according to the control strategy. If the control force exceeds the actuator`s capacity limit, it is set equal to that limit. The concept of the control strategy employed herein is to apply the control force at every time step to cancel the system velocity induced at the preceding time step so that the gradual rhythmic buildup of the response is destroyed. The ground motions considered in the numerical example are the 1940 El Centro earthquake and the 1979 Imperial Valley earthquake in California. The system responses with and without the control are calculated and compared. The feasibility and potential of applying ANNs to seismic active control is asserted by the promising results obtained from the numerical examples studied.

  13. Sound Sequence Discrimination Learning Motivated by Reward Requires Dopaminergic D2 Receptor Activation in the Rat Auditory Cortex

    ERIC Educational Resources Information Center

    Kudoh, Masaharu; Shibuki, Katsuei

    2006-01-01

    We have previously reported that sound sequence discrimination learning requires cholinergic inputs to the auditory cortex (AC) in rats. In that study, reward was used for motivating discrimination behavior in rats. Therefore, dopaminergic inputs mediating reward signals may have an important role in the learning. We tested the possibility in the…

  14. Chasing Sounds

    PubMed Central

    Neiworth, Julie J

    2012-01-01

    Prior work with Wright and others demonstrated that rhesus monkeys recognized the relative relationships of notes in common melodies. As an extension of tests of pattern similarities, tamarins were habituated to 3-sound unit patterns in an AAB or ABB form that were human phonemes, piano notes, or monkey calls. The subjects were tested with novel sounds in each category constructed either to match the prior pattern or to violate the prior habituated pattern. The monkeys attended significantly more to a violation of their habituated pattern to a new pattern when human phonemes were used, and there was a trend difference in attention toward pattern violations with melodies. Monkey call patterns generated a variety of behavioral responses, were less likely to show habituation, and did not generate a strong attention reaction to changes in the patterns. Monkeys can extract abstract rules and patterns from auditory stimuli but the stimuli, by their nature, may generate competing responses which block processing of abstract regularities. PMID:23219981

  15. Piezoelectric Power Requirements for Active Vibration Control

    NASA Technical Reports Server (NTRS)

    Brennan, Matthew C.; McGowan, Anna-Maria Rivas

    1997-01-01

    This paper presents a method for predicting the power consumption of piezoelectric actuators utilized for active vibration control. Analytical developments and experimental tests show that the maximum power required to control a structure using surface-bonded piezoelectric actuators is independent of the dynamics between the piezoelectric actuator and the host structure. The results demonstrate that for a perfectly-controlled system, the power consumption is a function of the quantity and type of piezoelectric actuators and the voltage and frequency of the control law output signal. Furthermore, as control effectiveness decreases, the power consumption of the piezoelectric actuators decreases. In addition, experimental results revealed a non-linear behavior in the material properties of piezoelectric actuators. The material non- linearity displayed a significant increase in capacitance with an increase in excitation voltage. Tests show that if the non-linearity of the capacitance was accounted for, a conservative estimate of the power can easily be determined.

  16. Actively Controlled Shaft Seals for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Salant, Richard F.; Wolff, Paul

    1995-01-01

    This study experimentally investigates an actively controlled mechanical seal for aerospace applications. The seal of interest is a gas seal, which is considerably more compact than previous actively controlled mechanical seals that were developed for industrial use. In a mechanical seal, the radial convergence of the seal interface has a primary effect on the film thickness. Active control of the film thickness is established by controlling the radial convergence of the seal interface with a piezoelectric actuator. An actively controlled mechanical seal was initially designed and evaluated using a mathematical model. Based on these results, a seal was fabricated and tested under laboratory conditions. The seal was tested with both helium and air, at rotational speeds up to 3770 rad/sec, and at sealed pressures as high as 1.48 x 10(exp 6) Pa. The seal was operated with both manual control and with a closed-loop control system that used either the leakage rate or face temperature as the feedback. The output of the controller was the voltage applied to the piezoelectric actuator. The seal operated successfully for both short term tests (less than one hour) and for longer term tests (four hours) with a closed-loop control system. The leakage rates were typically 5-15 slm (standard liters per minute), and the face temperatures were generally maintained below 100C. When leakage rate was used as the feedback signal, the setpoint leakage rate was typically maintained within 1 slm. However, larger deviations occurred during sudden changes in sealed pressure. When face temperature was used as the feedback signal, the setpoint face temperature was generally maintained within 3 C, with larger deviations occurring when the sealed pressure changes suddenly. the experimental results were compared to the predictions from the mathematical model. The model was successful in predicting the trends in leakage rate that occurred as the balance ratio and sealed pressure changed

  17. Neural predictive control for active buffet alleviation

    NASA Astrophysics Data System (ADS)

    Pado, Lawrence E.; Lichtenwalner, Peter F.; Liguore, Salvatore L.; Drouin, Donald

    1998-06-01

    The adaptive neural control of aeroelastic response (ANCAR) and the affordable loads and dynamics independent research and development (IRAD) programs at the Boeing Company jointly examined using neural network based active control technology for alleviating undesirable vibration and aeroelastic response in a scale model aircraft vertical tail. The potential benefits of adaptive control includes reducing aeroelastic response associated with buffet and atmospheric turbulence, increasing flutter margins, and reducing response associated with nonlinear phenomenon like limit cycle oscillations. By reducing vibration levels and thus loads, aircraft structures can have lower acquisition cost, reduced maintenance, and extended lifetimes. Wind tunnel tests were undertaken on a rigid 15% scale aircraft in Boeing's mini-speed wind tunnel, which is used for testing at very low air speeds up to 80 mph. The model included a dynamically scaled flexible fail consisting of an aluminum spar with balsa wood cross sections with a hydraulically powered rudder. Neural predictive control was used to actuate the vertical tail rudder in response to strain gauge feedback to alleviate buffeting effects. First mode RMS strain reduction of 50% was achieved. The neural predictive control system was developed and implemented by the Boeing Company to provide an intelligent, adaptive control architecture for smart structures applications with automated synthesis, self-optimization, real-time adaptation, nonlinear control, and fault tolerance capabilities. It is designed to solve complex control problems though a process of automated synthesis, eliminating costly control design and surpassing it in many instances by accounting for real world non-linearities.

  18. Dielectric elastomer actuators for active microfluidic control

    NASA Astrophysics Data System (ADS)

    McCoul, David; Murray, Coleman; Di Carlo, Dino; Pei, Qibing

    2013-04-01

    Dielectric elastomers with low modulus and large actuation strain have been investigated for applications in which they serve as "active" microfluidic channel walls. Anisotropically prestrained acrylic elastomer membranes are bonded to cover open trenches formed on a silicone elastomer substrate. Actuation of the elastomer membranes increases the cross-sectional area of the resulting channels, in turn controlling hydraulic flow rate and pressure. Bias voltage increases the active area of the membranes, allowing intrachannel pressure to alter channel geometry. The channels have also demonstrated the ability to actively clear a blockage. Applications may include adaptive microfilters, micro-peristaltic pumps, and reduced-complexity lab-on-a-chip devices.

  19. MODELING MERCURY CONTROL WITH POWDERED ACTIVATED CARBON

    EPA Science Inventory

    The paper presents a mathematical model of total mercury removed from the flue gas at coal-fired plants equipped with powdered activated carbon (PAC) injection for Mercury control. The developed algorithms account for mercury removal by both existing equipment and an added PAC in...

  20. DNA-based control of protein activity

    PubMed Central

    Engelen, W.; Janssen, B. M. G.

    2016-01-01

    DNA has emerged as a highly versatile construction material for nanometer-sized structures and sophisticated molecular machines and circuits. The successful application of nucleic acid based systems greatly relies on their ability to autonomously sense and act on their environment. In this feature article, the development of DNA-based strategies to dynamically control protein activity via oligonucleotide triggers is discussed. Depending on the desired application, protein activity can be controlled by directly conjugating them to an oligonucleotide handle, or expressing them as a fusion protein with DNA binding motifs. To control proteins without modifying them chemically or genetically, multivalent ligands and aptamers that reversibly inhibit their function provide valuable tools to regulate proteins in a noncovalent manner. The goal of this feature article is to give an overview of strategies developed to control protein activity via oligonucleotide-based triggers, as well as hurdles yet to be taken to obtain fully autonomous systems that interrogate, process and act on their environments by means of DNA-based protein control. PMID:26812623

  1. Sound exposure of professional orchestral musicians during solitary practice.

    PubMed

    O'Brien, Ian; Driscoll, Tim; Ackermann, Bronwen

    2013-10-01

    It is broadly acknowledged that professional orchestral musicians risk noise-induced hearing pathologies due to sound exposure in rehearsal and performance. While much has been published regarding orchestral sound levels, little is known of the sound exposure these musicians experience during solitary practice, despite the many hours they spend engaged in this activity. This study aimed to determine sound exposure during solitary practice of 35 professional orchestral musicians, representing players of most orchestral instruments. To allow cross-comparison, participants were assessed playing similar repertoire in a controlled environment, recording simultaneously at each ear to determine sound exposure levels. Sound levels were recorded between 60 and 107 dB L(Aeq), with peak levels between 101 and 130 dB L(C,peak). For average reported practice durations (2.1 h per day, five days a week) 53% would exceed accepted permissible daily noise exposure in solitary practice, in addition to sound exposure during orchestral rehearsals and performances. Significant inter-aural differences were noted in violin, viola, flute/piccolo, horn, trombone, and tuba. Only 40% used hearing protection at any time while practicing. These findings indicate orchestral musicians at risk of noise-induced hearing loss in ensemble face significant additional risks during solitary practice. Data presented will enable more effective and targeted management strategies for this population. PMID:24116413

  2. Sound exposure of professional orchestral musicians during solitary practice.

    PubMed

    O'Brien, Ian; Driscoll, Tim; Ackermann, Bronwen

    2013-10-01

    It is broadly acknowledged that professional orchestral musicians risk noise-induced hearing pathologies due to sound exposure in rehearsal and performance. While much has been published regarding orchestral sound levels, little is known of the sound exposure these musicians experience during solitary practice, despite the many hours they spend engaged in this activity. This study aimed to determine sound exposure during solitary practice of 35 professional orchestral musicians, representing players of most orchestral instruments. To allow cross-comparison, participants were assessed playing similar repertoire in a controlled environment, recording simultaneously at each ear to determine sound exposure levels. Sound levels were recorded between 60 and 107 dB L(Aeq), with peak levels between 101 and 130 dB L(C,peak). For average reported practice durations (2.1 h per day, five days a week) 53% would exceed accepted permissible daily noise exposure in solitary practice, in addition to sound exposure during orchestral rehearsals and performances. Significant inter-aural differences were noted in violin, viola, flute/piccolo, horn, trombone, and tuba. Only 40% used hearing protection at any time while practicing. These findings indicate orchestral musicians at risk of noise-induced hearing loss in ensemble face significant additional risks during solitary practice. Data presented will enable more effective and targeted management strategies for this population.

  3. Active control of multiple resistive wall modes

    NASA Astrophysics Data System (ADS)

    Brunsell, P. R.; Yadikin, D.; Gregoratto, D.; Paccagnella, R.; Liu, Y. Q.; Bolzonella, T.; Cecconello, M.; Drake, J. R.; Kuldkepp, M.; Manduchi, G.; Marchiori, G.; Marrelli, L.; Martin, P.; Menmuir, S.; Ortolani, S.; Rachlew, E.; Spizzo, G.; Zanca, P.

    2005-12-01

    A two-dimensional array of saddle coils at Mc poloidal and Nc toroidal positions is used on the EXTRAP T2R reversed-field pinch (Brunsell P R et al 2001 Plasma Phys. Control. Fusion 43 1457) to study active control of resistive wall modes (RWMs). Spontaneous growth of several RWMs with poloidal mode number m = 1 and different toroidal mode number n is observed experimentally, in agreement with linear MHD modelling. The measured plasma response to a controlled coil field and the plasma response computed using the linear circular cylinder MHD model are in quantitive agreement. Feedback control introduces a linear coupling of modes with toroidal mode numbers n, n' that fulfil the condition |n - n'| = Nc. Pairs of coupled unstable RWMs are present in feedback experiments with an array of Mc × Nc = 4 × 16 coils. Using intelligent shell feedback, the coupled modes are generally not controlled even though the field is suppressed at the active coils. A better suppression of coupled modes may be achieved in the case of rotating modes by using the mode control feedback scheme with individually set complex gains. In feedback with a larger array of Mc × Nc = 4 × 32 coils, the coupling effect largely disappears, and with this array, the main internal RWMs n = -11, -10, +5, +6 are all simultaneously suppressed throughout the discharge (7 8 wall times). With feedback there is a two-fold extension of the pulse length, compared to discharges without feedback.

  4. Control Systems Cyber Security Standards Support Activities

    SciTech Connect

    Robert Evans

    2009-01-01

    The Department of Homeland Security’s Control Systems Security Program (CSSP) is working with industry to secure critical infrastructure sectors from cyber intrusions that could compromise control systems. This document describes CSSP’s current activities with industry organizations in developing cyber security standards for control systems. In addition, it summarizes the standards work being conducted by organizations within the sector and provides a brief listing of sector meetings and conferences that might be of interest for each sector. Control systems cyber security standards are part of a rapidly changing environment. The participation of CSSP in the development effort for these standards has provided consistency in the technical content of the standards while ensuring that information developed by CSSP is included.

  5. Actively controlled vibration welding system and method

    DOEpatents

    Cai, Wayne W.; Kang, Bongsu; Tan, Chin-An

    2013-04-02

    A vibration welding system includes a controller, welding horn, an active material element, and anvil assembly. The assembly may include an anvil body connected to a back plate and support member. The element, e.g., a piezoelectric stack or shape memory alloy, is positioned with respect to the assembly. The horn vibrates in a desirable first direction to form a weld on a work piece. The element controls any vibrations in a second direction by applying calibrated response to the anvil body in the second direction. A method for controlling undesirable vibrations in the system includes positioning the element with respect to the anvil assembly, connecting the anvil body to the support member through the back plate, vibrating the horn in a desirable first direction, and transmitting an input signal to the element to control vibration in an undesirable second direction.

  6. Signal transducer and activator of transcription 2 (STAT2) metabolism coupling postmitotic outgrowth to visual and sound perception network in human left cerebrum by biocomputation.

    PubMed

    Wang, Lin; Huang, Juxiang; Jiang, Minghu; Lin, Hong

    2012-07-01

    We constructed the high-expression signal transducer and activator of transcription 2 (STAT2) metabolism coupling postmitotic outgrowth to visual and sound perception network in human left cerebrum compared with low-expression (fold change ≥2) chimpanzee left cerebrum in GEO data set by using integration of gene regulatory network inference method with gene ontology (GO) analysis of STAT2-activated up- and downstream network. Our result showed that upstream RECQL, PDIA2, ENOSF1, THBS4, RASGRP1, PER2, PDE8A, ORC2L, DCI, OGG1_2, SMA4, GPD1, etc. activated STAT2, and downstream STAT2-activated GSTM3_1, GOSR1, SH3BGR, OSBPL8, PHYH, SAPS2, C21orf33, PDIA2, TRAPPC6A, ENOSF1, CAMTA1, GTF2I_2, etc. in human left cerebrum. STAT2-activated network enhanced regulation of small GTPase-mediated signal transduction, regulation of transcription, regulation of mitosis, regulation of cell growth, positive regulation of phosphoinositide 3-kinase cascade, positive regulation of fat cell differentiation, negative regulation of DNA replication, negative regulation of progression through cell cycle, cyclic nucleotide metabolism, lipid metabolism, carbohydrate metabolism, vitamin A metabolism, N-acetylglucosamine metabolism, UDP-N-acetylgalactosamine metabolism, fatty acid transport, intracellular protein transport, vesicle-mediated transport, lipid transport, retrograde transport, Ras protein signal transduction, Wnt receptor signaling pathway, nervous system development, cell extension, cell adhesion, cell differentiation, circadian rhythm, generation of precursor metabolites and energy, establishment of blood-nerve barrier, visual perception, sensory perception of sound, and poly-N-acetyllactosamine biosynthesis, as a result of inducing metabolism coupling postmitotic outgrowth to visual and sound perception in human left cerebrum.

  7. 16 Years, 16 Cruises, 1.6 Billion Soundings: a Compilation of High-Resolution Multibeam Bathymetry of the Active Plate Boundary Along the Chilean Continental Margin

    NASA Astrophysics Data System (ADS)

    Weinrebe, W.; Flueh, E. R.; Hasert, M.; Behrmann, J. H.; Voelker, D.; Geersen, J.; Ranero, C. R.; Diaz-Naveas, J. L.

    2011-12-01

    Chile, a country stranding the active plate boundary between the South-American and the Nazca Plate is afflicted by recurrent earthquakes and hazardous volcanic eruptions. The strongest earthquake ever recorded occurred here, and volcanic hazards are frequent. Consequently, this area has been studied by geoscientists for many years to improve the understanding of subduction zone processes. Swath bathymetry mapping of the ocean floor has proven to bear a large potential for the interpretation of subduction-related processes, such as tectonic deformation of the marine forearc, release and migration of fluids as well as earthquake-triggered mass wasting. Multibeam bathymetry data of 16 major cruises of German, British, and Chilean research vessels recorded between 1995 and December 2010, in total more than 10,000 data files comprising about 1.6 billion soundings, have now been carefully reprocessed, compiled and merged into a unifying set of high-resolution bathymetric maps of the Chilean continental margin from latitude 40°S to 20°S. The imprint of subsurface processes on the surface morphology is well displayed in the case of the Chilean continental margin. The 3,500 km long Chilean convergent margin is not uniform, as various segments with different tectonic characteristics can be distinguished. Major factors that control margin morphology and thus the style of subduction are (1) relief and structure of the incoming oceanic plate, (2) supply of trench sediment, (3) turbidite transport within the trench, and (4) the input of terrigeneous sediments down the continental slope. A major segment boundary occurs at latitude 32°-33° S where the hotspot-related volcanic chain of Juan Fernandez is presently subducting. South of the area of ridge subduction the trench is filled with turbidites, and accretionary ridges develop across the base of the slope along most of the segment, whereas north of this boundary the turbiditic infill is reduced and subduction erosion is

  8. Optogenetic feedback control of neural activity

    PubMed Central

    Newman, Jonathan P; Fong, Ming-fai; Millard, Daniel C; Whitmire, Clarissa J; Stanley, Garrett B; Potter, Steve M

    2015-01-01

    Optogenetic techniques enable precise excitation and inhibition of firing in specified neuronal populations and artifact-free recording of firing activity. Several studies have suggested that optical stimulation provides the precision and dynamic range requisite for closed-loop neuronal control, but no approach yet permits feedback control of neuronal firing. Here we present the ‘optoclamp’, a feedback control technology that provides continuous, real-time adjustments of bidirectional optical stimulation in order to lock spiking activity at specified targets over timescales ranging from seconds to days. We demonstrate how this system can be used to decouple neuronal firing levels from ongoing changes in network excitability due to multi-hour periods of glutamatergic or GABAergic neurotransmission blockade in vitro as well as impinging vibrissal sensory drive in vivo. This technology enables continuous, precise optical control of firing in neuronal populations in order to disentangle causally related variables of circuit activation in a physiologically and ethologically relevant manner. DOI: http://dx.doi.org/10.7554/eLife.07192.001 PMID:26140329

  9. Method of sound synthesis

    DOEpatents

    Miner, Nadine E.; Caudell, Thomas P.

    2004-06-08

    A sound synthesis method for modeling and synthesizing dynamic, parameterized sounds. The sound synthesis method yields perceptually convincing sounds and provides flexibility through model parameterization. By manipulating model parameters, a variety of related, but perceptually different sounds can be generated. The result is subtle changes in sounds, in addition to synthesis of a variety of sounds, all from a small set of models. The sound models can change dynamically according to changes in the simulation environment. The method is applicable to both stochastic (impulse-based) and non-stochastic (pitched) sounds.

  10. Earth Observing System/Meteorological Satellite (EOS/METSAT). Advanced Microwave Sounding Unit-A (AMSU-A) Contamination Control Plan

    NASA Technical Reports Server (NTRS)

    Fay, M.

    1998-01-01

    This Contamination Control Plan is submitted in response the Contract Document requirements List (CDRL) 007 under contract NAS5-32314 for the Earth Observing System (EOS) Advanced Microwave Sounding Unit A (AMSU-A). In response to the CDRL instructions, this document defines the level of cleanliness and methods/procedures to be followed to achieve adequate cleanliness/contamination control, and defines the required approach to maintain cleanliness/contamination control through shipping, observatory integration, test, and flight. This plan is also applicable to the Meteorological Satellite (METSAT) except where requirements are identified as EOS-specific. This plan is based on two key factors: a. The EOS/METSAT AMSU-A Instruments are not highly contamination sensitive. b. Potential contamination of other EOS Instruments is a key concern as addressed in Section 9/0 of the Performance Assurance Requirements for EOS/METSAT Integrated Programs AMSU-A Instrument (MR) (NASA Specification S-480-79).

  11. Active control of ultrasonic hearing in frogs.

    PubMed

    Gridi-Papp, Marcos; Feng, Albert S; Shen, Jun-Xian; Yu, Zu-Lin; Rosowski, John J; Narins, Peter M

    2008-08-01

    Vertebrates can modulate the sound levels entering their inner ears in the face of intense external sound or during their own vocalizations. Middle ear muscle contractions restrain the motion of the middle ear ossicles, attenuating the transmission of low-frequency sound and thereby protecting the hair cells in the inner ear. Here we show that the Chinese concave-eared torrent frog, Odorrana tormota, can tune its ears dynamically by closing its normally open Eustachian tubes. Contrary to the belief that the middle ear in frogs permanently communicates with the mouth, O. tormota can close this connection by contraction of the submaxillary and petrohyoid muscles, drastically reducing the air volume behind the eardrums. Mathematical modeling and laser Doppler vibrometry revealed that the reduction of this air volume increases the middle ear impedance, resulting in an up to 20 dB gain in eardrum vibration at high frequencies (10-32 kHz) and 26 dB attenuation at low frequencies (3-10 kHz). Eustachian tube closure was observed in the field during calling and swallowing. Besides a potential role in protecting the inner ear from intense low-frequency sound and high buccal air pressure during calling, this previously unrecognized vertebrate mechanism may unmask the high-frequency calls of this species from the low-frequency stream noise which dominates the environment. This mechanism also protects the thin tympanic membranes from injury during swallowing of live arthropod prey.

  12. Electromagnetic sounding of the Earth's crust in the region of superdeep boreholes of Yamal-Nenets autonomous district using the fields of natural and controlled sources

    NASA Astrophysics Data System (ADS)

    Zhamaletdinov, A. A.; Petrishchev, M. S.; Shevtsov, A. N.; Kolobov, V. V.; Selivanov, V. N.; Barannik, M. B.; Tereshchenko, E. D.; Grigoriev, V. F.; Sergushin, P. A.; Kopytenko, E. A.; Biryulya, M. A.; Skorokhodov, A. A.; Esipko, O. A.; Damaskin, R. V.

    2013-11-01

    Electromagnetic soundings with the fields of natural (magnetotelluric (MT), and audio magnetotelluric (AMT)) and high-power controlled sources have been carried out in the region of the SG-6 (Tyumen) and SG-7 (En-Yakhin) superdeep boreholes in the Yamal-Nenets autonomous district (YaNAD). In the controlled-source soundings, the electromagnetic field was generated by the VL Urengoi-Pangody 220-kV industrial power transmission line (PTL), which has a length of 114 km, and ultralow-frequency (ULF) Zevs radiating antenna located at a distance of 2000 km from the signal recording sites. In the soundings with the Urengoi-Pangody PTL, the Energiya-2 generator capable of supplying up to 200 kW of power and Energiya-3 portable generator with a power of 2 kW were used as the sources. These generators were designed and manufactured at the Kola Science Center of the Russian Academy of Sciences. The soundings with the Energiya-2 generator were conducted in the frequency range from 0.38 to 175 Hz. The external generator was connected to the PTL in upon the agreement with the Yamal-Nenets Enterprise of Main Electric Networks, a branch of OAO FSK ES of Western Siberia. The connection was carried out by the wire-ground scheme during the routine maintenance of PTL in the nighttime. The highest-quality signals were recorded in the region of the SG-7 (En-Yakhin) superdeep borehole, where the industrial noise is lowest. The results of the inversion of the soundings with PTL and Zevs ULF transmitter completely agree with each other and with the data of electric logging. The MT-AMT data provide additional information about the deep structure of the region in the low-frequency range (below 1Hz). It is established that the section of SG-6 and SG-7 boreholes contains conductive layers in the depth intervals from 0.15 to 0.3 km and from 1 to 1.5 km. These layers are associated with the variations in the lithological composition, porosity, and fluid saturation of the rocks. The top of the

  13. Sound localization and occupational noise

    PubMed Central

    de Lemos Menezes, Pedro; de Andrade, Kelly Cristina Lira; Tenório Lins Carnaúba, Aline; Cabral, Frantänia B.; de Carvalho Leal, Mariana; Desgualdo Pereira, Liliane

    2014-01-01

    OBJECTIVE: The aim of this study was to determine the effects of occupational noise on sound localization in different spatial planes and frequencies among normal hearing firefighters. METHOD: A total of 29 adults with pure-tone hearing thresholds below 25 dB took part in the study. The participants were divided into a group of 19 firefighters exposed to occupational noise and a control group of 10 adults who were not exposed to such noise. All subjects were assigned a sound localization task involving 117 stimuli from 13 sound sources that were spatially distributed in horizontal, vertical, midsagittal and transverse planes. The three stimuli, which were square waves with fundamental frequencies of 500, 2,000 and 4,000 Hz, were presented at a sound level of 70 dB and were randomly repeated three times from each sound source. The angle between the speaker's axis in the same plane was 45°, and the distance to the subject was 1 m. RESULT: The results demonstrate that the sound localization ability of the firefighters was significantly lower (p<0.01) than that of the control group. CONCLUSION: Exposure to occupational noise, even when not resulting in hearing loss, may lead to a diminished ability to locate a sound source. PMID:24519197

  14. Unsteady aerodynamic modeling and active aeroelastic control

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1977-01-01

    Unsteady aerodynamic modeling techniques are developed and applied to the study of active control of elastic vehicles. The problem of active control of a supercritical flutter mode poses a definite design goal stability, and is treated in detail. The transfer functions relating the arbitrary airfoil motions to the airloads are derived from the Laplace transforms of the linearized airload expressions for incompressible two dimensional flow. The transfer function relating the motions to the circulatory part of these loads is recognized as the Theodorsen function extended to complex values of reduced frequency, and is termed the generalized Theodorsen function. Inversion of the Laplace transforms yields exact transient airloads and airfoil motions. Exact root loci of aeroelastic modes are calculated, providing quantitative information regarding subcritical and supercritical flutter conditions.

  15. Active control of locomotion facilitates nonvisual navigation.

    PubMed

    Philbeck, J W; Klatzky, R L; Behrmann, M; Loomis, J M; Goodridge, J

    2001-02-01

    In some navigation tasks, participants are more accurate if they view the environment beforehand. To characterize the benefits associated with visual previews, 32 blindfolded participants were guided along simple paths and asked to walk unassisted to a specified destination (e.g., the origin). Paths were completed without vision, with or without a visual preview of the environment. Previews did not necessarily improve nonvisual navigation. When previewed landmarks stood near the origin or at off-path locations, they provided little benefit; by contrast, when they specified intermediate destinations (thereby increasing the degree of active control), performance was greatly enhanced. The results suggest that the benefit of a visual preview stems from the information it supplies for actively controlled locomotion. Accuracy in reaching the final destination, however, is strongly contingent upon the destination's location during the preview.

  16. Advanced Active Thermal Control Systems Architecture Study

    NASA Technical Reports Server (NTRS)

    Hanford, Anthony J.; Ewert, Michael K.

    1996-01-01

    The Johnson Space Center (JSC) initiated a dynamic study to determine possible improvements available through advanced technologies (not used on previous or current human vehicles), identify promising development initiatives for advanced active thermal control systems (ATCS's), and help prioritize funding and personnel distribution among many research projects by providing a common basis to compare several diverse technologies. Some technologies included were two-phase thermal control systems, light-weight radiators, phase-change thermal storage, rotary fluid coupler, and heat pumps. JSC designed the study to estimate potential benefits from these various proposed and under-development thermal control technologies for five possible human missions early in the next century. The study compared all the technologies to a baseline mission using mass as a basis. Each baseline mission assumed an internal thermal control system; an external thermal control system; and aluminum, flow-through radiators. Solar vapor compression heat pumps and light-weight radiators showed the greatest promise as general advanced thermal technologies which can be applied across a range of missions. This initial study identified several other promising ATCS technologies which offer mass savings and other savings compared to traditional thermal control systems. Because the study format compares various architectures with a commonly defined baseline, it is versatile and expandable, and is expected to be updated as needed.

  17. Active Control of Fan Noise: Feasibility Study. Volume 3; Active Fan Noise Cancellation in the NASA Lewis Active Noise Control Fan Facility

    NASA Technical Reports Server (NTRS)

    Pla, Frederic G.; Hu, Ziqiang; Sutliff, Daniel L.

    1996-01-01

    This report describes the Active Noise Cancellation (ANC) System designed by General Electric and tested in the NASA Lewis Research Center's (LERC) 48 inch Active Noise Control Fan (ANCF). The goal of this study is to assess the feasibility of using wall mounted secondary acoustic sources and sensors within the duct of a high bypass turbofan aircraft engine for global active noise cancellation of fan tones. The GE ANC system is based on a modal control approach. A known acoustic mode propagating in the fan duct is canceled using an array of flush-mounted compact sound sources. The canceling modal signal is generated by a modal controller. Inputs to the controller are signals from a shaft encoder and from a microphone array which senses the residual acoustic mode in the duct. The key results are that the (6,0) was completely eliminated at the 920 Hz design frequency and substantially reduced elsewhere. The total tone power was reduced 6.8 dB (out of a possible 9.8 dB). Farfield reductions of 15 dB (SPL) were obtained. The (4,0) and (4,1) modes were reduced simultaneously yielding a 15 dB PWL decrease. The results indicate that global attenuation of PWL at the target frequency was obtained in the aft quadrant using an ANC actuator and sensor system totally contained within the duct. The quality of the results depended on precise mode generation. High spillover into spurious modes generated by the ANC actuator array caused less than optimum levels of PWL reduction. The variation in spillover is believed to be due to calibration procedure, but must be confirmed in subsequent tests.

  18. Sound focusing in rooms: the time-reversal approach.

    PubMed

    Yon, Sylvain; Tanter, Mickael; Fink, Mathias

    2003-03-01

    New perspectives in audible range acoustics, such as virtual sound space creation and active noise control, rely on the ability of the rendering system to recreate precisely a desired sound field. This ability to control sound in a given volume of a room is directly linked to the capacity to focus acoustical energy both in space and time. However, sound focusing in rooms remains a complicated problem, essentially because of the multiple reflections on obstacles and walls occurring during propagation. In this paper, the technique of time-reversal focusing, well known in ultrasound, is experimentally applied to audible range acoustics. Compared to classical focusing techniques such as delay law focusing, time reversal appears to considerably improve quality of both temporal and spatial focusing. This so-called super-resolution phenomenon is due to the ability of time reversal to take into account all of the different sound paths between the emitting antenna and the focal point, thus creating an adaptive spatial and temporal matched filter for the considered propagation medium. Experiments emphasize the strong robustness of time-reversal focusing towards small modifications in the medium, such as people in motion or temperature variations. Sound focusing through walls using the time-reversal approach is also experimentally demonstrated. PMID:12656388

  19. Sounds of Space

    NASA Astrophysics Data System (ADS)

    Gurnett, D. A.

    2005-12-01

    Starting in the early 1960s, spacecraft-borne plasma wave instruments revealed that space is filled with an astonishing variety of radio and plasma wave sounds, which have come to be called "sounds of space." For over forty years these sounds have been collected and played to a wide variety of audiences, often as the result of press conferences or press releases involving various NASA projects for which the University of Iowa has provided plasma wave instruments. This activity has led to many interviews on local and national radio programs, and occasionally on programs haviang world-wide coverage, such as the BBC. As a result of this media coverage, we have been approached many times by composers requesting copies of our space sounds for use in their various projects, many of which involve electronic synthesis of music. One of these collaborations led to "Sun Rings," which is a musical event produced by the Kronos Quartet that has played to large audiences all over the world. With the availability of modern computer graphic techniques we have recently been attempting to integrate some of these sound of space into an educational audio/video web site that illustrates the scientific principles involved in the origin of space plasma waves. Typically I try to emphasize that a substantial gas pressure exists everywhere in space in the form of an ionized gas called a plasma, and that this plasma can lead to a wide variety of wave phenomenon. Examples of some of this audio/video material will be presented.

  20. Active Thermal Control System Development for Exploration

    NASA Technical Reports Server (NTRS)

    Westheimer, David

    2007-01-01

    All space vehicles or habitats require thermal management to maintain a safe and operational environment for both crew and hardware. Active Thermal Control Systems (ATCS) perform the functions of acquiring heat from both crew and hardware within a vehicle, transporting that heat throughout the vehicle, and finally rejecting that energy into space. Almost all of the energy used in a space vehicle eventually turns into heat, which must be rejected in order to maintain an energy balance and temperature control of the vehicle. For crewed vehicles, Active Thermal Control Systems are pumped fluid loops that are made up of components designed to perform these functions. NASA has been actively developing technologies that will enable future missions or will provide significant improvements over the state of the art technologies. These technologies have are targeted for application on the Crew Exploration Vehicle (CEV), or Orion, and a Lunar Surface Access Module (LSAM). The technologies that have been selected and are currently under development include: fluids that enable single loop ATCS architectures, a gravity insensitive vapor compression cycle heat pump, a sublimator with reduced sensitivity to feedwater contamination, an evaporative heat sink that can operate in multiple ambient pressure environments, a compact spray evaporator, and lightweight radiators that take advantage of carbon composites and advanced optical coatings.

  1. Distributed control system for active mirrors

    NASA Astrophysics Data System (ADS)

    Rodriguez-Ramos, Luis F.; Williams, Mark R.; Castro, Javier; Cruz, A.; Gonzalez, Juan C.; Mack, Brian; Martin, Carlos; Pescador, German; Sanchez, Vicente; Sosa, Nicolas A.

    1994-06-01

    This paper presents the IAC (Instituto de Astrofisica de Canaries, Spain) proposal of a distributed control system intended for the active support of a 8 m mirror. The system incorporates a large number of compact `smart' force actuators, six force definers, and a mirror support computer (MSC) for interfacing with the telescope control system and for general housekeeping. We propose the use of a network for the interconnection of the actuators, definers and the MSC, which will minimize the physical complexity of the interface between the mirror support system and the MSC. The force actuator control electronics are described in detail, as is the system software architecture of the actuator and the MSC. As the network is a key point for the system, we also detail the evaluation of three candidates, before electing the CAN bus.

  2. Evidence for two-dimensional solitary sound waves in a lipid controlled interface and its implications for biological signalling.

    PubMed

    Shrivastava, Shamit; Schneider, Matthias F

    2014-08-01

    Biological membranes by virtue of their elastic properties should be capable of propagating localized perturbations analogous to sound waves. However, the existence and the possible role of such waves in communication in biology remain unexplored. Here, we report the first observations of two-dimensional solitary elastic pulses in lipid interfaces, excited mechanically and detected by FRET. We demonstrate that the nonlinearity near a maximum in the susceptibility of the lipid monolayer results in solitary pulses that also have a threshold for excitation. These experiments clearly demonstrate that the state of the interface regulates the propagation of pulses both qualitatively and quantitatively. Finally, we elaborate on the striking similarity of the observed phenomenon to nerve pulse propagation and a thermodynamic basis of cell signalling in general.

  3. The Middeck Active Control Experiment (MACE)

    NASA Technical Reports Server (NTRS)

    Miller, David W.; Sepe, Raymond B.; Rey, Daniel; Saarmaa, Erik; Crawley, Edward F.

    1993-01-01

    The Middeck Active Control Experiment (MACE) is a NASA In-Step and Control Structure Interaction (CSI) Office funded Shuttle middeck experiment. The objective is to investigate the extent to which closed-loop behavior of flexible spacecraft in zero-gravity (0-g) can be predicted. This prediction becomes particularly difficult when dynamic behavior during ground testing exhibits extensive suspension and direct gravity coupling. On-orbit system identification and control reconfiguration is investigated to improve performance which would otherwise be limited due to errors in prediction. The program is presently in its preliminary design phase with launch expected in the summer of 1994. The MACE test article consists of three attitude control torque wheels, a two axis gimballing payload, inertial sensors and a flexible support structure. With the acquisition of a second payload, this will represent a multiple payload platform with significant structural flexibility. This paper presents on-going work in the areas of modelling and control of the MACE test article in the zero and one-gravity environments. Finite element models, which include suspension and gravity effects, and measurement models, derived from experimental data, are used as the basis for Linear Quadratic Gaussian controller designs. Finite element based controllers are analytically used to study the differences in closed-loop performance as the test article transitions between the 0-g and 1-g environments. Measurement based controllers are experimentally applied to the MACE test article in the 1-g environment and achieve over an order of magnitude improvement in payload pointing accuracy when disturbed by a broadband torque disturbance. The various aspects of the flight portion of the experiment are also discussed.

  4. Middeck Active Control Experiment (MACE), phase A

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Deluis, Javier; Miller, David W.

    1989-01-01

    A rationale to determine which structural experiments are sufficient to verify the design of structures employing Controlled Structures Technology was derived. A survey of proposed NASA missions was undertaken to identify candidate test articles for use in the Middeck Active Control Experiment (MACE). The survey revealed that potential test articles could be classified into one of three roles: development, demonstration, and qualification, depending on the maturity of the technology and the mission the structure must fulfill. A set of criteria was derived that allowed determination of which role a potential test article must fulfill. A review of the capabilities and limitations of the STS middeck was conducted. A reference design for the MACE test article was presented. Computing requirements for running typical closed-loop controllers was determined, and various computer configurations were studied. The various components required to manufacture the structure were identified. A management plan was established for the remainder of the program experiment development, flight and ground systems development, and integration to the carrier. Procedures for configuration control, fiscal control, and safety, reliabilty, and quality assurance were developed.

  5. Local flow control for active building facades

    NASA Astrophysics Data System (ADS)

    Kaligotla, Srikar; Chen, Wayne; Glauser, Mark

    2010-11-01

    Existing building facade designs are for a passive and an impermeable shell to prevent migration of outdoor air into the building and to control heat transfers between the exterior environment and the building interior. An active facade that can respond in real time to changing environmental conditions like wind speed and direction, pollutant load, temperature, humidity and light can lower energy use and maximize occupant comfort. With an increased awareness of cost and environmental effects of energy use, cross or natural ventilation has become an attractive method to lower energy use. Separated flow regions around such buildings are undesirable due to high concentration of pollutants, especially if the vents or dynamic windows for cross ventilation are situated in these regions. Outside pollutant load redistribution through vents can be regulated via flow separation control to minimize transport of pollutants into the building. Flow separation has been substantially reduced with the application of intelligent flow control tools developed at Syracuse University for flow around "silo" (turret) like structures. Similar flow control models can be introduced into buildings with cross ventilation for local external flow separation control. Initial experiments will be performed for turbulent flow over a rectangular block (scaled to be a mid-rise building) that has been configured with dynamic vents and unsteady suction actuators in a wind tunnel at various wind speeds.

  6. Concerns of the Institute of Transport Study and Research for reducing the sound level inside completely repaired buses. [noise and vibration control

    NASA Technical Reports Server (NTRS)

    Groza, A.; Calciu, J.; Nicola, I.; Ionasek, A.

    1974-01-01

    Sound level measurements on noise sources on buses are used to observe the effects of attenuating acoustic pressure levels inside the bus by sound-proofing during complete repair. A spectral analysis of the sound level as a function of motor speed, bus speed along the road, and the category of the road is reported.

  7. Active optics control development at the LBT

    NASA Astrophysics Data System (ADS)

    Ashby, David S.; Biddick, Christopher; Hill, John M.

    2014-07-01

    The Large Binocular Telescope (LBT) is built around two 8.4 m-diameter primary mirrors placed with a centerline separation of 14.4 m in a common altitude/azimuth mount. Each side of the telescope can utilize a deployable prime focus instrument; alternatively, the beam can be directed to a Gregorian instrument by utilizing a deployable secondary mirror. The direct-Gregorian beam can be intercepted and redirected to several bent-Gregorian instruments by utilizing a deployable tertiary mirror. Two of the available bent-Gregorian instruments are interferometers, capable of coherently combining the beams from the two sides of the telescope. Active optics can utilize as many as 26 linearly independent degrees of freedom to position the primary, secondary and tertiary mirrors to control optical collimation while the telescope operates in its numerous observing modes. Additionally, by applying differential forces at 160 locations on each primary mirror, active optics controls the primary mirror figure. The authors explore the challenges associated with collimation and primary mirror figure control at the LBT and outline the ongoing related development aimed at optimizing image quality and preparing the telescope for interferometric operations.

  8. Korotkoff Sounds.

    PubMed

    Shennan; Halligan

    1996-12-01

    We were interested in the historical perspective that Arabidze et al. [1] brought to the subject of Korotkoff's auscultatory method of measuring blood pressure. The original description by the Reverend Stephen Hales performing the very first blood pressure measurement (which was actually published in 1733) does not make reference to a column of water as the authors suggest [2]. Hales wrote: 'Then untying the Ligature on the Artery, the Blood rose in the Tube eight Feet three Inches.'. He goes on to state that, 'When it was at its full Height, it would rise and fall at and after each Pulse two, three, or four Inches, and sometimes it would fall twelve or fourteen Inches, and have there for a time the same vibrations up and down at and after each Pulse, as it had, when it was at its full Height; to which it would rise again, after forty or fifty Pulses'. We believe this fall of '12 or 14 in' to have been the first description of blood pressure variability, which has wrongly been attributed to respirations by subsequent authors [3]. The mare's pulse rate was described to be about 50 beats per minute; therefore an unanaesthetized horse would not be likely to have a respiration rate of once per minute. One further important point of error concerning the Korotkoff sounds is their reproducibility. We have demonstrated recently that phase IV is reproduced or identified poorly, both in adults and even during pregnancy, when it has been recommended to be used in favour of phase V. We have also demonstrated that phase I (systolic blood pressure) is perceived to be significantly clearer than phase V [4]. PMID:10226281

  9. Noise and vibration control engineering - Principles and applications

    NASA Astrophysics Data System (ADS)

    Beranek, Leo L.; Ver, Istvan L.

    The present work discusses waves and impedances, the determination of sound power levels and directivity, outdoor sound propagation, sound in small enclosures, noise in rooms, sound-absorbing materials and sound absorbers, the interactions of sound waves with solid structures, vibration isolation, and structural damping. Also discussed are enclosures and wrappings, active noise control, damage-risk criteria for hearing and human body vibration, criteria for noise and vibration in communities, buildings, and vehicles, machinery noise prediction, noise and vibration control for internal combustion engines, noise and vibration of electrical machinery, and elements of gear noise prediction. (No individual items are abstracted in this volume)

  10. Gas turbine engine active clearance control

    NASA Technical Reports Server (NTRS)

    Deveau, Paul J. (Inventor); Greenberg, Paul B. (Inventor); Paolillo, Roger E. (Inventor)

    1985-01-01

    Method for controlling the clearance between rotating and stationary components of a gas turbine engine are disclosed. Techniques for achieving close correspondence between the radial position of rotor blade tips and the circumscribing outer air seals are disclosed. In one embodiment turbine case temperature modifying air is provided in flow rate, pressure and temperature varied as a function of engine operating condition. The modifying air is scheduled from a modulating and mixing valve supplied with dual source compressor air. One source supplies relatively low pressure, low temperature air and the other source supplies relatively high pressure, high temperature air. After the air has been used for the active clearance control (cooling the high pressure turbine case) it is then used for cooling the structure that supports the outer air seal and other high pressure turbine component parts.

  11. Control concepts for active magnetic bearings

    NASA Technical Reports Server (NTRS)

    Siegwart, Roland; Vischer, D.; Larsonneur, R.; Herzog, R.; Traxler, Alfons; Bleuler, H.; Schweitzer, G.

    1992-01-01

    Active Magnetic Bearings (AMB) are becoming increasingly significant for various industrial applications. Examples are turbo-compressors, centrifuges, high speed milling and grinding spindles, vibration isolation, linear guides, magnetically levitated trains, vacuum and space applications. Thanks to the rapid progress and drastic cost reduction in power- and micro-electronics, the number of AMB applications is growing very rapidly. Industrial uses of AMBs leads to new requirements for AMB-actuators, sensor systems, and rotor dynamics. Especially desirable are new and better control concepts to meet demand such as low cost AMB, high stiffness, high performance, high robustness, high damping up to several kHz, vibration isolation, force-free rotation, and unbalance cancellation. This paper surveys various control concepts for AMBs and discusses their advantages and disadvantages. Theoretical and experimental results are presented.

  12. Understanding the brain by controlling neural activity

    PubMed Central

    Krug, Kristine; Salzman, C. Daniel; Waddell, Scott

    2015-01-01

    Causal methods to interrogate brain function have been employed since the advent of modern neuroscience in the nineteenth century. Initially, randomly placed electrodes and stimulation of parts of the living brain were used to localize specific functions to these areas. Recent technical developments have rejuvenated this approach by providing more precise tools to dissect the neural circuits underlying behaviour, perception and cognition. Carefully controlled behavioural experiments have been combined with electrical devices, targeted genetically encoded tools and neurochemical approaches to manipulate information processing in the brain. The ability to control brain activity in these ways not only deepens our understanding of brain function but also provides new avenues for clinical intervention, particularly in conditions where brain processing has gone awry. PMID:26240417

  13. Active Displacement Control of Active Magnetic Bearing System

    NASA Astrophysics Data System (ADS)

    Kertész, Milan; Kozakovič, Radko; Magdolen, Luboš; Masaryk, Michal

    2014-12-01

    The worldwide energy production nowadays is over 3400 GW while storage systems have a capacity of only 90 GW [1]. There is a good solution for additional storage capacity in flywheel energy storage systems (FES). The main advantage of FES is its relatively high efficiency especially with using the active magnetic bearing system. Therefore there exist good reasons for appropriate simulations and for creating a suitable magneto-structural control system. The magnetic bearing, including actuation, is simulated in the ANSYS parametric design language (APDL). APDL is used to create the loops of transient simulations where boundary conditions (BC) are updated based upon a "gap sensor" which controls the nodal position values of the centroid of the shaft and the current density inputs onto the copper windings.

  14. Active Aircraft Pylon Noise Control System

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H. (Inventor); Czech, Michael J (Inventor); Elmiligui, Alaa A. (Inventor)

    2015-01-01

    An active pylon noise control system for an aircraft includes a pylon structure connecting an engine system with an airframe surface of the aircraft and having at least one aperture to supply a gas or fluid therethrough, an intake portion attached to the pylon structure to intake a gas or fluid, a regulator connected with the intake portion via a plurality of pipes, to regulate a pressure of the gas or fluid, a plenum chamber formed within the pylon structure and connected with the regulator, and configured to receive the gas or fluid as regulated by the regulator, and a plurality of injectors in communication with the plenum chamber to actively inject the gas or fluid through the plurality of apertures of the pylon structure.

  15. Nanomechanics of Actively Controlled Deployable Optics

    NASA Technical Reports Server (NTRS)

    Peterson, Lee D.

    2000-01-01

    This document is the interim, annual report for the research grant entitled "Nanomechanics of Actively Controlled Deployed Optics." It is supported by NASA Langley Research Center Cooperative Agreement NCC-1 -281. Dr. Mark S. Lake is the technical monitor of the research program. This document reports activities for the year 1998, beginning 3/11/1998, and for the year 1999. The objective of this report is to summarize the results and the status of this research. This summary appears in Section 2.0. Complete details of the results of this research have been reported in several papers, publications and theses. Section 3.0 lists these publications and, when available, presents their abstracts. Each publication is available in electronic form from a web site identified in Section 3.0.

  16. The effect of Clostridium botulinum toxin type A injections on motor unit activity of the deep digital flexor muscle in healthy sound Royal Dutch sport horses.

    PubMed

    Wijnberg, Inge D; Hardeman, Lotte C; van der Meij, Bram R; Veraa, Stefanie; Back, Willem; van der Kolk, Johannes H

    2013-12-01

    Therapeutic reduction of the activity of the deep digital flexor (DDF) muscle may play a role in treatment of laminitic horses. Clostridium botulinum toxin type A induces reduced muscle activity and has a spasmolytic effect in horses. In this study, the effectiveness of 200 IU C. botulinum toxin type A on reduction of DDF muscle activity was measured in seven healthy, sound, adult Royal Dutch sport horses. C. botulinum toxin type A was injected using ultrasound and electromyographic (EMG) guidance. The effectiveness was assessed by interference pattern analysis (IPA) and motor unit action potential (MUAP) analysis. All needle EMG MUAP variables, along with IPA amplitude/turn and turns/s, were significantly reduced after C. botulinum toxin type A injections. The strongest effect occurred within the first 3 days after injection. The reduced muscle induced by C. botulinum toxin type A may have benefits in the treatment of horses with laminitis. PMID:24360760

  17. EEG sensorimotor correlates of translating sounds into actions

    PubMed Central

    Pineda, Jaime A.; Grichanik, Mark; Williams, Vanessa; Trieu, Michelle; Chang, Hailey; Keysers, Christian

    2013-01-01

    Understanding the actions of others is a necessary foundational cornerstone for effective and affective social interactions. Such understanding may result from a mapping of observed actions as well as heard sounds onto one's own motor representations of those events. To examine the electrophysiological basis of action-related sounds, EEG data were collected in two studies from adults who were exposed to auditory events in one of three categories: action (either hand- or mouth-based sounds), non-action (environmental sounds), and control sounds (scrambled versions of action sounds). In both studies, triplets of sounds of the same category were typically presented, although occasionally, to ensure an attentive state, trials containing a sound from a different category were presented within the triplet and participants were asked to respond to this oddball event either covertly in one study or overtly in another. Additionally, participants in both studies were asked to mimic hand- and mouth-based motor actions associated with the sounds (motor task). Action sounds elicited larger EEG mu rhythm (8–13 Hz) suppression, relative to control sounds, primarily over left hemisphere, while non-action sounds showed larger mu suppression primarily over right hemisphere. Furthermore, hand-based sounds elicited greater mu suppression over the hand area in sensorimotor cortex compared to mouth-based sounds. These patterns of mu suppression across cortical regions to different categories of sounds and to effector-specific sounds suggest differential engagement of a mirroring system in the human brain when processing sounds. PMID:24376395

  18. Decentralized harmonic active vibration control of a flexible plate using piezoelectric actuator-sensor pairs.

    PubMed

    Baudry, Matthieu; Micheau, Philippe; Berry, Alain

    2006-01-01

    We have investigated decentralized active control of periodic panel vibration using multiple pairs combining PZT actuators and PVDF sensors distributed on the panel. By contrast with centralized MIMO controllers used to actively control the vibrations or the sound radiation of extended structures, decentralized control using independent local control loops only requires identification of the diagonal terms in the plant matrix. However, it is difficult to a priori predict the global stability of such decentralized control. In this study, the general situation of noncollocated actuator-sensor pairs was considered. Frequency domain gradient and Newton-Raphson adaptation of decentralized control were analyzed, both in terms of performance and stability conditions. The stability conditions are especially derived in terms of the adaptation coefficient and a control effort weighting coefficient. Simulations and experimental results are presented in the case of a simply supported panel with four PZT-PVDF pairs distributed on it. Decentralized vibration control is shown to be highly dependent on the frequency, but can be as effective as a fully centralized control even when the plant matrix is not diagonal-dominant or is not strictly positive real (not dissipative).

  19. Active Region Soft X-Ray Spectra as Observed Using Sounding Rocket Measurements from the Solar Aspect Monitor (SAM), - a Modified SDO/EVE Instrument

    NASA Astrophysics Data System (ADS)

    Wieman, S. R.; Didkovsky, L. V.; Woods, T. N.; Jones, A. R.; Caspi, A.; Warren, H. P.

    2015-12-01

    Observations of solar active regions (ARs) in the soft x-ray spectral range (0.5 to 3.0 nm) were made on sounding rocket flight NASA 36.290 using a modified Solar Aspect Monitor (SAM), a pinhole camera on the EUV Variability Experiment (EVE) sounding rocket instrument. The suite of EVE rocket instruments is designed for under-flight calibrations of the orbital EVE on SDO. While the sounding rocket EVE instrument is for the most part a duplicate of the EVE on SDO, the SAM channel on the rocket version was modified in 2012 to include a free-standing transmission grating so that it could provide spectrally resolved images of the solar disk with the best signal to noise ratio for the brightest features on it, such as ARs. Calibrations of the EVE sounding rocket instrument at the National Institute of Standards and Technology Synchrotron Ultraviolet Radiation Facility (NIST SURF) have provided a measurement of the SAM absolute spectral response function and a mapping of wavelength separation in the grating diffraction pattern. For solar observations, this spectral separation is on a similar scale to the spatial size of the AR on the CCD, so dispersed AR images associated with emission lines of similar wavelength tend to overlap. Furthermore, SAM shares a CCD detector with MEGS-A, a separate EVE spectrometer channel, and artifacts of the MEGS-A signal (a set of bright spectral lines) appear in the SAM images. For these reasons some processing and analysis of the solar images obtained by SAM must be performed in order to determine spectra of the observed ARs. We present a method for determining AR spectra from the SAM rocket images and report initial soft X-ray spectra for two of the major active regions (AR11877 and AR11875) observed on flight 36.290 on 21 October 2013 at about 18:30 UT. We also compare our results with concurrent measurements from other solar soft x-ray instrumentation.

  20. Making Sound Connections

    ERIC Educational Resources Information Center

    Deal, Walter F., III

    2007-01-01

    Sound provides and offers amazing insights into the world. Sound waves may be defined as mechanical energy that moves through air or other medium as a longitudinal wave and consists of pressure fluctuations. Humans and animals alike use sound as a means of communication and a tool for survival. Mammals, such as bats, use ultrasonic sound waves to…

  1. The Sound of Science

    ERIC Educational Resources Information Center

    Merwade, Venkatesh; Eichinger, David; Harriger, Bradley; Doherty, Erin; Habben, Ryan

    2014-01-01

    While the science of sound can be taught by explaining the concept of sound waves and vibrations, the authors of this article focused their efforts on creating a more engaging way to teach the science of sound--through engineering design. In this article they share the experience of teaching sound to third graders through an engineering challenge…

  2. Sounds Exaggerate Visual Shape

    ERIC Educational Resources Information Center

    Sweeny, Timothy D.; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    While perceiving speech, people see mouth shapes that are systematically associated with sounds. In particular, a vertically stretched mouth produces a /woo/ sound, whereas a horizontally stretched mouth produces a /wee/ sound. We demonstrate that hearing these speech sounds alters how we see aspect ratio, a basic visual feature that contributes…

  3. Using Therapeutic Sound With Progressive Audiologic Tinnitus Management

    PubMed Central

    Henry, James A.; Zaugg, Tara L.; Myers, Paula J.; Schechter, Martin A.

    2008-01-01

    Management of tinnitus generally involves educational counseling, stress reduction, and/or the use of therapeutic sound. This article focuses on therapeutic sound, which can involve three objectives: (a) producing a sense of relief from tinnitus-associated stress (using soothing sound); (b) passively diverting attention away from tinnitus by reducing contrast between tinnitus and the acoustic environment (using background sound); and (c) actively diverting attention away from tinnitus (using interesting sound). Each of these goals can be accomplished using three different types of sound—broadly categorized as environmental sound, music, and speech—resulting in nine combinations of uses of sound and types of sound to manage tinnitus. The authors explain the uses and types of sound, how they can be combined, and how the different combinations are used with Progressive Audiologic Tinnitus Management. They also describe how sound is used with other sound-based methods of tinnitus management (Tinnitus Masking, Tinnitus Retraining Therapy, and Neuromonics). PMID:18664499

  4. The Impact of Eliminating Extraneous Sound and Light on Students' Achievement: An Empirical Study

    ERIC Educational Resources Information Center

    Mangipudy, Rajarajeswari

    2010-01-01

    The impact of eliminating extraneous sound and light on students' achievement was investigated under four conditions: Light and Sound controlled, Sound Only controlled, Light Only controlled and neither Light nor Sound controlled. Group, age and gender were the control variables. Four randomly selected groups of high school freshmen students with…

  5. Secondary Path Modeling Method for Active Noise Control of Power Transformer

    NASA Astrophysics Data System (ADS)

    Zhao, Tong; Liang, Jiabi; Liang, Yuanbin; Wang, Lixin; Pei, Xiugao; Li, Peng

    The accuracy of the secondary path modeling is critical to the stability of active noise control system. On condition of knowing the input and output of the secondary path, system identification theory can be used to identify the path. Based on the experiment data, correlation analysis is adopted to eliminate the random noise and nonlinear harmonic in the output data in order to obtain the accurate frequency characteristic of the secondary path. After that, Levy's Method is applied to identify the transfer function of the path. Computer simulation results are given respectively, both showing the proposed off-line modeling method is feasible and applicable. At last, Levy's Method is used to attain an accurate secondary path model in the active control of transformer noise experiment and achieves to make the noise sound level decrease about 10dB.

  6. Sound Investments.

    ERIC Educational Resources Information Center

    Feudo, John

    1996-01-01

    Five tactics used by the University of Massachusetts to make alumni operations effective with minimal cost include assuring the campus administration's commitment to alumni club programming, training chapter volunteers on campus and through regional visits, controlling mailing costs, planning events in a cost-effective manner, and deciding whether…

  7. Inducing physiological stress recovery with sounds of nature in a virtual reality forest--results from a pilot study.

    PubMed

    Annerstedt, Matilda; Jönsson, Peter; Wallergård, Mattias; Johansson, Gerd; Karlson, Björn; Grahn, Patrik; Hansen, Ase Marie; Währborg, Peter

    2013-06-13

    Experimental research on stress recovery in natural environments is limited, as is study of the effect of sounds of nature. After inducing stress by means of a virtual stress test, we explored physiological recovery in two different virtual natural environments (with and without exposure to sounds of nature) and in one control condition. Cardiovascular data and saliva cortisol were collected. Repeated ANOVA measurements indicated parasympathetic activation in the group subjected to sounds of nature in a virtual natural environment, suggesting enhanced stress recovery may occur in such surroundings. The group that recovered in virtual nature without sound and the control group displayed no particular autonomic activation or deactivation. The results demonstrate a potential mechanistic link between nature, the sounds of nature, and stress recovery, and suggest the potential importance of virtual reality as a tool in this research field.

  8. Amplitude Scaling of Active Separation Control

    NASA Technical Reports Server (NTRS)

    Stalnov, Oksana; Seifert, Avraham

    2010-01-01

    Three existing and two new excitation magnitude scaling options for active separation control at Reynolds numbers below one Million. The physical background for the scaling options was discussed and their relevance was evaluated using two different sets of experimental data. For F+ approx. 1, 2D excitation: a) The traditional VR and C(mu) - do not scale the data. b) Only the Re*C(mu) is valid. This conclusion is also limited for positive lift increment.. For F+ > 10, 3D excitation, the Re corrected C(mu), the St corrected velocity ratio and the vorticity flux coefficient, all scale the amplitudes equally well. Therefore, the Reynolds weighted C(mu) is the preferred choice, relevant to both excitation modes. Incidence also considered, using Ue from local Cp.

  9. Ribosome-dependent activation of stringent control.

    PubMed

    Brown, Alan; Fernández, Israel S; Gordiyenko, Yuliya; Ramakrishnan, V

    2016-06-01

    In order to survive, bacteria continually sense, and respond to, environmental fluctuations. Stringent control represents a key bacterial stress response to nutrient starvation that leads to rapid and comprehensive reprogramming of metabolic and transcriptional patterns. In general, transcription of genes for growth and proliferation is downregulated, while those important for survival and virulence are upregulated. Amino acid starvation is sensed by depletion of the aminoacylated tRNA pools, and this results in accumulation of ribosomes stalled with non-aminoacylated (uncharged) tRNA in the ribosomal A site. RelA is recruited to stalled ribosomes and activated to synthesize a hyperphosphorylated guanosine analogue, (p)ppGpp, which acts as a pleiotropic secondary messenger. However, structural information about how RelA recognizes stalled ribosomes and discriminates against aminoacylated tRNAs is missing. Here we present the cryo-electron microscopy structure of RelA bound to the bacterial ribosome stalled with uncharged tRNA. The structure reveals that RelA utilizes a distinct binding site compared to the translational factors, with a multi-domain architecture that wraps around a highly distorted A-site tRNA. The TGS (ThrRS, GTPase and SpoT) domain of RelA binds the CCA tail to orient the free 3' hydroxyl group of the terminal adenosine towards a β-strand, such that an aminoacylated tRNA at this position would be sterically precluded. The structure supports a model in which association of RelA with the ribosome suppresses auto-inhibition to activate synthesis of (p)ppGpp and initiate the stringent response. Since stringent control is responsible for the survival of pathogenic bacteria under stress conditions, and contributes to chronic infections and antibiotic tolerance, RelA represents a good target for the development of novel antibacterial therapeutics. PMID:27279228

  10. Active Control of Wind Tunnel Noise

    NASA Technical Reports Server (NTRS)

    Hollis, Patrick (Principal Investigator)

    1991-01-01

    The need for an adaptive active control system was realized, since a wind tunnel is subjected to variations in air velocity, temperature, air turbulence, and some other factors such as nonlinearity. Among many adaptive algorithms, the Least Mean Squares (LMS) algorithm, which is the simplest one, has been used in an Active Noise Control (ANC) system by some researchers. However, Eriksson's results, Eriksson (1985), showed instability in the ANC system with an ER filter for random noise input. The Restricted Least Squares (RLS) algorithm, although computationally more complex than the LMS algorithm, has better convergence and stability properties. The ANC system in the present work was simulated by using an FIR filter with an RLS algorithm for different inputs and for a number of plant models. Simulation results for the ANC system with acoustic feedback showed better robustness when used with the RLS algorithm than with the LMS algorithm for all types of inputs. Overall attenuation in the frequency domain was better in the case of the RLS adaptive algorithm. Simulation results with a more realistic plant model and an RLS adaptive algorithm showed a slower convergence rate than the case with an acoustic plant as a delay plant. However, the attenuation properties were satisfactory for the simulated system with the modified plant. The effect of filter length on the rate of convergence and attenuation was studied. It was found that the rate of convergence decreases with increase in filter length, whereas the attenuation increases with increase in filter length. The final design of the ANC system was simulated and found to have a reasonable convergence rate and good attenuation properties for an input containing discrete frequencies and random noise.

  11. Modeling and active vibration control of six-DOF manipulator through μ-synthesis with parameter uncertainties

    NASA Astrophysics Data System (ADS)

    Yu, Kaiping; Wu, Ying

    2015-02-01

    A new linear dynamic model of a six-spherical-prismatic-spherical (SPS) Stewart platform with the base excitation was formulated via Kane's method. In order to satisfy the practical situation, the uncertainties of mass center location, stiffness and damping were concerned. Then a robust μ-synthesis controller was developed by applying D-K iteration to attenuate the base excitation. Comparisons were conducted by analyzing the responses of the open and closed loops in the frequency and time domain. Simulation results indicated that the proposed robust controller is of fine properties and good robustness, which laid a sound foundation of active micro-vibration control of a satellite.

  12. Sensor Development for Active Flow Control

    NASA Technical Reports Server (NTRS)

    Kahng, Seun K.; Gorton, Susan A.; Mau, Johnney C.; Soto, Hector L.; Hernandez, Corey D.

    2001-01-01

    Presented are the developmental efforts for MEMS sensors for a closed-loop active flow control in a low-speed wind tunnel evaluation. The MEMS sensors are designed in-house and fabricated out of house, and the shear sensors are a thermal type that are collocated with temperature and pressure sensors on a flexible polyimide sheet, which conforms to surfaces of a simple curvature. A total of 6 sensors are located within a 1.5 by 3 mm area as a cluster with each sensor being 300 pm square. The thickness of this sensor cluster is 75 pm. Outputs from the shear sensors have been compared with respect to those of the Preston tube for evaluation of the sensors on a flat plate. Pressure sensors are the absolute type and have recorded pressure measurements within 0.05 percent of the tunnel ESP pressure sensor readings. The sensors and signal conditioning electronics have been tested on both a flat plate and a ramp in Langley s 15-Inch Low-Turbulence Tunnel. The system configuration and control PC is configured with LabView, where calibration constants are stored for desired compensation and correction. The preliminary test results are presented within.

  13. Active controlled studies in antibiotic drug development.

    PubMed

    Dane, Aaron

    2011-01-01

    The increasing concern of antibacterial resistance has been well documented, as has the relative lack of antibiotic development. This paradox is in part due to challenges with clinical development of antibiotics. Because of their rapid progression, untreated bacterial infections are associated with significant morbidity and mortality. As a consequence, placebo-controlled studies of new agents are unethical. Rather, pivotal development studies are mostly conducted using non-inferiority designs versus an active comparator. Further, infections because of comparator-resistant isolates must usually be excluded from the trial programme. Unfortunately, the placebo-controlled data classically used in support of non-inferiority designs are largely unavailable for antibiotics. The only available data are from the 1930s and 1940s and their use is associated with significant concerns regarding constancy and assay sensitivity. Extended public debate on this challenge has led to proposed solutions by some in which these concerns are addressed by using very conservative approaches to trial design, endpoints and non-inferiority margins, in some cases leading to potentially impractical studies. To compound this challenge, different Regulatory Authorities seem to be taking different approaches to these key issues. If harmonisation does not occur, antibiotic development will become increasingly challenging, with the risk of further decreases in the amount of antibiotic drug development. However with clarity on Regulatory requirements and an ability to feasibly conduct global development programmes, it should be possible to bring much needed additional antibiotics to patients.

  14. Actively controlled thin-shell space optics

    NASA Astrophysics Data System (ADS)

    Denoyer, Keith K.; Flint, Eric M.; Main, John A.; Lindler, Jason E.

    2003-08-01

    Increasingly, scientific and military missions require the use of space-based optical systems. For example, new capabilities are required for imaging terrestrial like planets, for surveillance, and for directed energy applications. Given the difficulties in producing and launching large optics, it is doubtful that refinements of conventional technology will meet future needs, particularly in a cost-effective manner. To meet this need, recent research has been investigating the feasibility of a new class of ultra-lightweight think-skin optical elements that combine recent advances in lightweight thermally formed materials, active materials, and novel sensing and control architectures. If successful, the approach may lead to an order of magnitude reduction in space optics areal density, improved large scale manufacturing capability, and dramatic reductions in manufacturing and launch costs. In a recent effort, a one meter thin-film mirror like structure was fabricated. This paper provides an overview of tools used to model and simulate this structure as well as results from structural dynamic testing. In addition, progress in the area of non-contact global shape control using smart materials is presented.

  15. High performance composites with active stiffness control.

    PubMed

    Tridech, Charnwit; Maples, Henry A; Robinson, Paul; Bismarck, Alexander

    2013-09-25

    High performance carbon fiber reinforced composites with controllable stiffness could revolutionize the use of composite materials in structural applications. Here we describe a structural material, which has a stiffness that can be actively controlled on demand. Such a material could have applications in morphing wings or deployable structures. A carbon fiber reinforced-epoxy composite is described that can undergo an 88% reduction in flexural stiffness at elevated temperatures and fully recover when cooled, with no discernible damage or loss in properties. Once the stiffness has been reduced, the required deformations can be achieved at much lower actuation forces. For this proof-of-concept study a thin polyacrylamide (PAAm) layer was electrocoated onto carbon fibers that were then embedded into an epoxy matrix via resin infusion. Heating the PAAm coating above its glass transition temperature caused it to soften and allowed the fibers to slide within the matrix. To produce the stiffness change the carbon fibers were used as resistance heating elements by passing a current through them. When the PAAm coating had softened, the ability of the interphase to transfer load to the fibers was significantly reduced, greatly lowering the flexural stiffness of the composite. By changing the moisture content in PAAm fiber coating, the temperature at which the PAAm softens and the composites undergo a reduction in stiffness can be tuned. PMID:23978266

  16. Moth hearing and sound communication.

    PubMed

    Nakano, Ryo; Takanashi, Takuma; Surlykke, Annemarie

    2015-01-01

    Active echolocation enables bats to orient and hunt the night sky for insects. As a counter-measure against the severe predation pressure many nocturnal insects have evolved ears sensitive to ultrasonic bat calls. In moths bat-detection was the principal purpose of hearing, as evidenced by comparable hearing physiology with best sensitivity in the bat echolocation range, 20-60 kHz, across moths in spite of diverse ear morphology. Some eared moths subsequently developed sound-producing organs to warn/startle/jam attacking bats and/or to communicate intraspecifically with sound. Not only the sounds for interaction with bats, but also mating signals are within the frequency range where bats echolocate, indicating that sound communication developed after hearing by "sensory exploitation". Recent findings on moth sound communication reveal that close-range (~ a few cm) communication with low-intensity ultrasounds "whispered" by males during courtship is not uncommon, contrary to the general notion of moths predominantly being silent. Sexual sound communication in moths may apply to many eared moths, perhaps even a majority. The low intensities and high frequencies explain that this was overlooked, revealing a bias towards what humans can sense, when studying (acoustic) communication in animals.

  17. Moth hearing and sound communication.

    PubMed

    Nakano, Ryo; Takanashi, Takuma; Surlykke, Annemarie

    2015-01-01

    Active echolocation enables bats to orient and hunt the night sky for insects. As a counter-measure against the severe predation pressure many nocturnal insects have evolved ears sensitive to ultrasonic bat calls. In moths bat-detection was the principal purpose of hearing, as evidenced by comparable hearing physiology with best sensitivity in the bat echolocation range, 20-60 kHz, across moths in spite of diverse ear morphology. Some eared moths subsequently developed sound-producing organs to warn/startle/jam attacking bats and/or to communicate intraspecifically with sound. Not only the sounds for interaction with bats, but also mating signals are within the frequency range where bats echolocate, indicating that sound communication developed after hearing by "sensory exploitation". Recent findings on moth sound communication reveal that close-range (~ a few cm) communication with low-intensity ultrasounds "whispered" by males during courtship is not uncommon, contrary to the general notion of moths predominantly being silent. Sexual sound communication in moths may apply to many eared moths, perhaps even a majority. The low intensities and high frequencies explain that this was overlooked, revealing a bias towards what humans can sense, when studying (acoustic) communication in animals. PMID:25261361

  18. Cortical control of thermoregulatory sympathetic activation.

    PubMed

    Fechir, M; Klega, A; Buchholz, H G; Pfeifer, N; Balon, S; Schlereth, T; Geber, C; Breimhorst, M; Maihöfner, C; Birklein, F; Schreckenberger, M

    2010-06-01

    Thermoregulation enables adaptation to different ambient temperatures. A complex network of central autonomic centres may be involved. In contrast to the brainstem, the role of the cortex has not been clearly evaluated. This study was therefore designed to address cerebral function during a whole thermoregulatory cycle (cold, neutral and warm stimulation) using 18-fluordeoxyglucose-PET (FDG-PET). Sympathetic activation parameters were co-registered. Ten healthy male volunteers were examined three times on three different days in a water-perfused whole-body suit. After a baseline period (32 degrees C), temperature was either decreased to 7 degrees C (cold), increased to 50 degrees C (warm) or kept constant (32 degrees C, neutral), thereafter the PET examination was performed. Cerebral glucose metabolism was increased in infrapontine brainstem and cerebellar hemispheres during cooling and warming, each compared with neutral temperature. Simultaneously, FDG uptake decreased in the bilateral anterior/mid-cingulate cortex during warming, and in the right insula during cooling and warming. Conjunction analyses revealed that right insular deactivation and brainstem activation appeared both during cold and warm stimulation. Metabolic connectivity analyses revealed positive correlations between the cortical activations, and negative correlations between these cortical areas and brainstem/cerebellar regions. Heart rate changes negatively correlated with glucose metabolism in the anterior cingulate cortex and in the middle frontal gyrus/dorsolateral prefrontal cortex, and changes of sweating with glucose metabolism in the posterior cingulate cortex. In summary, these results suggest that the cerebral cortex exerts an inhibitory control on autonomic centres located in the brainstem or cerebellum. These findings may represent reasonable explanations for sympathetic hyperactivity, which occurs, for example, after hemispheric stroke.

  19. Robust controllers for the Middeck Active Control Experiment using Popov controller synthesis

    NASA Technical Reports Server (NTRS)

    How, Jonathan P.; Hall, Steven R.

    1993-01-01

    Recent work in robust control with real parameter uncertainties has focused on absolute stability and its connections to real mu theory. In particular, the research has investigated the Popov stability criterion and its associated Lur'e-Postnikov Liapunov functions. State space representations of this Popov stability analysis tests are included in an H2 design formulation to provide a powerful technique for robust controller synthesis. This synthesis approach uses a state space optimization procedure to design controllers that minimize an overbound of an H2 cost functional and satisfy stability analysis tests based on the Popov multiplier. The controller and stability multiplier coefficients are optimized simultaneously, which avoids the iteration and curve-fitting procedures required by the D-K algorithm of mu synthesis. While previous work has demonstrated this synthesis approach on benchmark control problems, the purpose of this paper is to use Popov controller synthesis to design robust compensators for the Middeck Active Control Experiment (MACE).

  20. Sound and emotion in Milton's Paradise lost.

    PubMed

    Whissell, Cynthia

    2011-08-01

    This research was designed to test the hypothesis that Milton's poem Paradise Lost is meaningfully patterned with respect to sound. Thirty-six segments from 12 Books of Paradise Lost were scored (Whissell, 2000) in terms of their proportional use of Pleasant, Cheerful, Active, Nasty, Unpleasant, Sad, Passive, and Soft sounds. Paradise Lost includes more Active, Nasty, and Unpleasant sounds and fewer Pleasant, Passive, Soft, and Sad sounds than a representative sample of anthologized poetry. The way in which emotional sounds are patterned (e.g., the rise and fall in the proportion of Pleasant sounds across Books) suggests the presence of three narratives within the work: Sin and Salvation-Foreseen in Heaven (Books I-II), The Fall of Man (Books IV-IX), and Sin and Salvation-Foretold on Earth (Books X-XI). The poem analyzed had updated spelling, and the author's exact intentions when creating it are not accessible to direct investigation, for this among other reasons.

  1. The NASA Sounding Rocket Program and space sciences.

    PubMed

    Gurkin, L W

    1992-10-01

    High altitude suborbital rockets (sounding rockets) have been extensively used for space science research in the post-World War II period; the NASA Sounding Rocket Program has been on-going since the inception of the Agency and supports all space science disciplines. In recent years, sounding rockets have been utilized to provide a low gravity environment for materials processing research, particularly in the commercial sector. Sounding rockets offer unique features as a low gravity flight platform. Quick response and low cost combine to provide more frequent spaceflight opportunities. Suborbital spacecraft design practice has achieved a high level of sophistication which optimizes the limited available flight times. High data-rate telemetry, real-time ground up-link command and down-link video data are routinely used in sounding rocket payloads. Standard, off-the-shelf, active control systems are available which limit payload body rates such that the gravitational environment remains less than 10(-4) g during the control period. Operational launch vehicles are available which can provide up to 7 minutes of experiment time for experiment weights up to 270 kg. Standard payload recovery systems allow soft impact retrieval of payloads. When launched from White Sands Missile Range, New Mexico, payloads can be retrieved and returned to the launch site within hours.

  2. Sound synthesis and evaluation of interactive footsteps and environmental sounds rendering for virtual reality applications.

    PubMed

    Nordahl, Rolf; Turchet, Luca; Serafin, Stefania

    2011-09-01

    We propose a system that affords real-time sound synthesis of footsteps on different materials. The system is based on microphones, which detect real footstep sounds from subjects, from which the ground reaction force (GRF) is estimated. Such GRF is used to control a sound synthesis engine based on physical models. Two experiments were conducted. In the first experiment, the ability of subjects to recognize the surface they were exposed to was assessed. In the second experiment, the sound synthesis engine was enhanced with environmental sounds. Results show that, in some conditions, adding a soundscape significantly improves the recognition of the simulated environment. PMID:21737860

  3. Effects of Text, Audio and Learner Control on Text-Sound Association and Cognitive Load of EFL Learners

    ERIC Educational Resources Information Center

    Enciso Bernal, Ana Maria

    2014-01-01

    This study investigated the effects of concurrent audio and equivalent onscreen text on the ability of learners of English as a foreign language (EFL) to form associations between textual and aural forms of target vocabulary words. The study also looked at the effects of learner control over an audio sequence on the association of textual and…

  4. Advanced modeling of active control of fan noise for ultra high bypass turbofan engines

    NASA Astrophysics Data System (ADS)

    Hutcheson, Florence Vanel

    1999-11-01

    An advanced model of active control of fan noise for ultra high bypass turbofan engines has been developed. This model is based on a boundary integral equation method and simulates the propagation, radiation and control of the noise generated by an engine fan surrounded by a duct of finite length and cylindrical shape, placed in a uniform flow. Control sources, modeled by point monopoles placed along the wall of the engine inlet or outlet duct, inject anti-noise into the duct to destructively interfere with the sound field generated by the fan. The duct inner wall can be lined or rigid. Unlike current methods, reflection from the duct openings is taken into account, as well as the presence of the evanescent modes. Forward, as well as backward (i.e., from the rear of the engine), external radiation is computed. The development of analytical expressions for the sound field resulting from both the fan loading noise and the control sources is presented. Two fan models are described. The first model uses spinning line sources with radially distributed strength to model the loading force that the fan blades exert on the medium. The second model uses radial arrays of spinning point dipoles to simulate the generation of fan modes of specific modal amplitudes. It is shown that these fan models can provide a reasonable approximation of actual engine fan noise in the instance when the modal amplitude of the propagating modes or the loading force distribution on the fan blades, is known. Sample cases of active noise control are performed to demonstrate the feasibility of the model. The results from these tests indicate that this model (1)is conducive to more realistic studies of active control of fan noise on ultra high bypass turbofan engines because it accounts for the presence of evanescent modes and for interference between inlet and outlet radiation, which were shown to have some impact on the performance of the active control system; (2)is very useful because it allows

  5. Active Region Soft X-Ray Spectra and Temperature Analyses based on Sounding Rocket Measurements from the Solar Aspect Monitor (SAM), - a Modified SDO/EVE Instrument

    NASA Astrophysics Data System (ADS)

    Didkovsky, Leonid V.; Wieman, Seth; Woods, Thomas N.; Jones, Andrew; Moore, Christopher

    2016-05-01

    Some initial results of soft x-ray spectral (0.5 to 3.0 nm) observations of active regions (AR11877 and AR11875) from a sounding rocket flight NASA 36.290 on 21 October 2013 at about 18:30 UT are reported. These observations were made by a Solar Aspect Monitor (SAM), a rocket version of the EUV Variability Experiment’s (EVE) channel, a pinhole camera modified for EVE rocket suite of instruments to include a free-standing transmission grating (200 nm period), which provided spectrally-resolved images of the solar disk. Intensity ratios for strong emission lines extracted from temporally averaged SAM spectral profiles of the ARs were compared to appropriately convolved modeled CHIANTI spectra. These ratios represent the AR’s temperature structures, which are compared to the structures derived from some other observations and temperature models.

  6. Utility of aeromagnetic studies for mapping of potentially active faults in two forearc basins: Puget Sound, Washington, and Cook Inlet, Alaska

    USGS Publications Warehouse

    Saltus, R.W.; Blakely, R.J.; Haeussler, P.J.; Wells, R.E.

    2005-01-01

    High-resolution aeromagnetic surveys over forearc basins can detect faults and folds in weakly magnetized sediments, thus providing geologic constraints on tectonic evolution and improved understanding of seismic hazards in convergent-margin settings. Puget Sound, Washington, and Cook Inlet, Alaska, provide two case histories. In each lowland region, shallow-source magnetic anomalies are related to active folds and/or faults. Mapping these structures is critical for understanding seismic hazards that face the urban regions of Seattle, Washington, and Anchorage, Alaska. Similarities in aeromagnetic anomaly patterns and magnetic stratigraphy between the two regions suggest that we can expect the aeromagnetic method to yield useful structural information that may contribute to earth-hazard and energy resource investigations in other forearc basins.

  7. The origin of the 900 Hz spectral peak in spontaneous and sound-evoked round-window electrical activity.

    PubMed

    McMahon, Catherine M; Patuzzi, Robert B

    2002-11-01

    presence of two peaks (P(1)* and N(2)*) which follow the intact N(1) peak. The P(1)* and N(2)* peaks were present at the RW, but not at the cochlear nerve as it exits the internal meatus, suggesting that they were not due to double-spiking of some of the neurones, but were probably due to a sub-threshold electrical resonance in the peripheral dendrites. We have successfully modelled the production of the SNN and the compound action potential and SAW in response to 0.25 ms and 25 ms tone-bursts at 20 kHz by including only a damped 900 Hz resonance in the UP, without refractory effects, preferred intervals or synchronisation in the timing of neural spike generation. Such resonances in other neurones are known to be due to the activation kinetics of the voltage-controlled sodium (Na(+)) channels of these neurones. The presence of such sub-threshold oscillations probably indicates that the peripheral dendrites are devoid of stabilising potassium (K(+)) channels. We also discuss the role of this membrane resonance in generating burst-firing of the cochlear nerve (as with salicylate) and the role of such burst-firing in generating tinnitus. PMID:12372642

  8. Sound wave transmission (image)

    MedlinePlus

    When sounds waves reach the ear, they are translated into nerve impulses. These impulses then travel to the brain where they are interpreted by the brain as sound. The hearing mechanisms within the inner ear, can ...

  9. Threshold for Onset of Injury in Chinook Salmon from Exposure to Impulsive Pile Driving Sounds

    PubMed Central

    Halvorsen, Michele B.; Casper, Brandon M.; Woodley, Christa M.; Carlson, Thomas J.; Popper, Arthur N.

    2012-01-01

    The risk of effects to fishes and other aquatic life from impulsive sound produced by activities such as pile driving and seismic exploration is increasing throughout the world, particularly with the increased exploitation of oceans for energy production. At the same time, there are few data that provide insight into the effects of these sounds on fishes. The goal of this study was to provide quantitative data to define the levels of impulsive sound that could result in the onset of barotrauma to fish. A High Intensity Controlled Impedance Fluid filled wave Tube was developed that enabled laboratory simulation of high-energy impulsive sound that were characteristic of aquatic far-field, plane-wave acoustic conditions. The sounds used were based upon the impulsive sounds generated by an impact hammer striking a steel shell pile. Neutrally buoyant juvenile Chinook salmon (Oncorhynchus tshawytscha) were exposed to impulsive sounds and subsequently evaluated for barotrauma injuries. Observed injuries ranged from mild hematomas at the lowest sound exposure levels to organ hemorrhage at the highest sound exposure levels. Frequency of observed injuries were used to compute a biological response weighted index (RWI) to evaluate the physiological impact of injuries at the different exposure levels. As single strike and cumulative sound exposure levels (SELss, SELcum respectively) increased, RWI values increased. Based on the results, tissue damage associated with adverse physiological costs occurred when the RWI was greater than 2. In terms of sound exposure levels a RWI of 2 was achieved for 1920 strikes by 177 dB re 1 µPa2⋅s SELss yielding a SELcum of 210 dB re 1 µPa2⋅s, and for 960 strikes by 180 dB re 1 µPa2⋅s SELss yielding a SELcum of 210 dB re 1 µPa2⋅s. These metrics define thresholds for onset of injury in juvenile Chinook salmon. PMID:22745695

  10. Active Noise Control of Low Speed Fan Rotor-Stator Modes

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.; Hu, Ziqiang; Pla, Frederic G.; Heidelberg, Laurence J.

    1996-01-01

    This report describes the Active Noise Cancellation System designed by General Electric and tested in the NASA Lewis Research Center's 48 inch Active Noise Control Fan. The goal of this study was to assess the feasibility of using wall mounted secondary acoustic sources and sensors within the duct of a high bypass turbofan aircraft engine for active noise cancellation of fan tones. The control system is based on a modal control approach. A known acoustic mode propagating in the fan duct is cancelled using an array of flush-mounted compact sound sources. Controller inputs are signals from a shaft encoder and a microphone array which senses the residual acoustic mode in the duct. The canceling modal signal is generated by a modal controller. The key results are that the (6,0) mode was completely eliminated at 920 Hz and substantially reduced elsewhere. The total tone power was reduced 9.4 dB. Farfield 2BPF SPL reductions of 13 dB were obtained. The (4,0) and (4,1) modes were reduced simultaneously yielding a 15 dB modal PWL decrease. Global attenuation of PWL was obtained using an actuator and sensor system totally contained within the duct.

  11. Sounds in the ocean at 1-100 Hz.

    PubMed

    Wilcock, William S D; Stafford, Kathleen M; Andrew, Rex K; Odom, Robert I

    2014-01-01

    Very-low-frequency sounds between 1 and 100 Hz propagate large distances in the ocean sound channel. Weather conditions, earthquakes, marine mammals, and anthropogenic activities influence sound levels in this band. Weather-related sounds result from interactions between waves, bubbles entrained by breaking waves, and the deformation of sea ice. Earthquakes generate sound in geologically active regions, and earthquake T waves propagate throughout the oceans. Blue and fin whales generate long bouts of sounds near 20 Hz that can dominate regional ambient noise levels seasonally. Anthropogenic sound sources include ship propellers, energy extraction, and seismic air guns and have been growing steadily. The increasing availability of long-term records of ocean sound will provide new opportunities for a deeper understanding of natural and anthropogenic sound sources and potential interactions between them. PMID:23876176

  12. Sounds in the ocean at 1-100 Hz.

    PubMed

    Wilcock, William S D; Stafford, Kathleen M; Andrew, Rex K; Odom, Robert I

    2014-01-01

    Very-low-frequency sounds between 1 and 100 Hz propagate large distances in the ocean sound channel. Weather conditions, earthquakes, marine mammals, and anthropogenic activities influence sound levels in this band. Weather-related sounds result from interactions between waves, bubbles entrained by breaking waves, and the deformation of sea ice. Earthquakes generate sound in geologically active regions, and earthquake T waves propagate throughout the oceans. Blue and fin whales generate long bouts of sounds near 20 Hz that can dominate regional ambient noise levels seasonally. Anthropogenic sound sources include ship propellers, energy extraction, and seismic air guns and have been growing steadily. The increasing availability of long-term records of ocean sound will provide new opportunities for a deeper understanding of natural and anthropogenic sound sources and potential interactions between them.

  13. Pest control industry and vector control activities in Taiwan.

    PubMed

    Wang, C H; Lin, C H; Liao, M J

    1994-12-01

    At the end of 1993, there were 117 private pest control companies in Taiwan, with 438 technical managers and 274 technicians. Their business includes the control of mosquitoes, cockroaches, fleas, rodents, termites, houseflies, etc. Pyrethroids and some organophosphates are employed. At present, no applications of insect growth regulators or microbial agents are used by private pest control operators. During dengue epidemics they assist the government in space spraying with insecticides. The Environmental Protection Administration, Executive Yuan, R.O.C., is responsible for the training and management of pest control operators. In addition, the Administration is also in charge of affairs concerning the manufacture, import, registration and sale of environmental pesticides and microbial agents. It establishes protocols for testing the efficacy of insecticides and promotes pest control on the community level.

  14. Active control of vibration using a neural network.

    PubMed

    Snyder, S D; Tanaka, N

    1995-01-01

    Feedforward control of sound and vibration using a neural network-based control system is considered, with the aim being to derive an architecture/algorithm combination which is capable of supplanting the commonly used finite impulse response filter/filtered-x least mean square (LMS) linear arrangement for certain nonlinear problems. An adaptive algorithm is derived which enables stable adaptation of the neural controller for this purpose, while providing the capacity to maintain causality within the control scheme. The algorithm is shown to be simply a generalization of the linear filtered-x LMS algorithm. Experiments are undertaken which demonstrate the utility of the proposed arrangement, showing that it performs as well as a linear control system for a linear control problem and better for a nonlinear control problem. The experiments also lead to the conclusion that more work is required to improve the predictability and consistency of the performance before the neural network controller becomes a practical alternative to the current linear feedforward systems.

  15. Sound Levels in East Texas Schools.

    ERIC Educational Resources Information Center

    Turner, Aaron Lynn

    A survey of sound levels was taken in several Texas schools to determine the amount of noise and sound present by size of class, type of activity, location of building, and the presence of air conditioning and large amounts of glass. The data indicate that class size and relative amounts of glass have no significant bearing on the production of…

  16. In-Situ Atmospheric Sounding Data Lifecycle from Data Collection, Analysis and Quality Control to Documentation, Archival and Tracking

    NASA Astrophysics Data System (ADS)

    Young, K.; Voemel, H.; Morris, D.

    2015-12-01

    In-situ measurement systems are used to monitor the atmosphere whereby instruments are located in the area of interest and are in direct contact with what is being measured. Dropsondes and radiosondes are instruments used to collect high-vertical-resolution profiles of the atmosphere. The dropsondes are deployed from aircraft and, as they descend, they collect pressure, temperature and humidity data at a half-second rate, and GPS wind data at a quarter-second rate. Radiosondes are used to collect high-resolution measurements of the atmosphere, from the ground to approximately 30 kilometers. Carried by a large helium-filled balloon, they ascend upward through the atmosphere measuring pressure, temperature, relative humidity, and GPS winds at a one-second rate. Advancements in atmospheric research, technology and data assimilation techniques have contributed to driving the need for higher quality, higher resolution radiosonde and dropsonde data at an increasingly rapid rate. These data most notably represent a valuable resource for initializing numerical prediction models, calibrating and validating satellite retrieval techniques for atmospheric profiles, and for climatological research. The In-Situ Sensing Facility, at NCAR, has developed an extensive, multi-step process of quality control (QC). Traditionally, QC has been a time intensive process that involves evaluating data products using a variety of visualization tools and statistical methods. With a greater need for real-time data in the field and a reduced turn-around time for final quality controlled data, new and improved procedures for streamlining statistical analysis and QC are being implemented. Improvements have also been made on two fronts regarding implementation of a comprehensive data management plan. The first was ensuring ease of data accessibility through an intuitive centralized data archive system, that both keeps a record of data users and assigns digital object identifiers to each unique data

  17. Making Sounds with Rubber Bands.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.

    This physical science activity module was designed to facilitate developing concepts related to sound. It is intended for use primarily in elementary grades but may be useful at higher grades. It provides students with hands-on experience and observational skill development. The package provides: (1) a teacher background sheet; (2) an activity…

  18. Rocket ozone sounding network data

    NASA Technical Reports Server (NTRS)

    Wright, D. U.; Krueger, A. J.; Foster, G. M.

    1978-01-01

    During the period December 1976 through February 1977, three regular monthly ozone profiles were measured at Wallops Flight Center, two special soundings were taken at Antigua, West Indies, and at the Churchill Research Range, monthly activities were initiated to establish stratospheric ozone climatology. This report presents the data results and flight profiles for the period covered.

  19. German scientific sounding rocket program

    NASA Astrophysics Data System (ADS)

    Roehrig, O.

    The German scientific sounding rocket program covers four disciplines: astronomy, aeronomy, magnetosphere, material science. In each of these disciplines there are ongoing projects (e.g., INTERZODIAK, STRAFAM, MAP-WINE, CAESAR, TEXUS). The scientific and technical aspects of these projects will be described. Emphasis will be given to some late technical achievements of DFVLR's Mobile Rocket Base (MORABA) giving support to most of the rocket campaigns. DFVLR-PT is authorized to act as management agency in order to perform and to coordinate German space activities of which the sounding rocket program forms a small part. A brief description of the organization will be given.

  20. Active flutter control for flexible vehicles, volume 1

    NASA Technical Reports Server (NTRS)

    Mahesh, J. K.; Garrard, W. L.; Stones, C. R.; Hausman, P. D.

    1979-01-01

    An active flutter control methodology based on linear quadratic gaussian theory and its application to the control of a super critical wing is presented. Results of control surface and sensor position optimization are discussed. Both frequency response matching and residualization used to obtain practical flutter controllers are examined. The development of algorithms and computer programs for flutter modeling and active control design procedures is reported.

  1. Hybrid mode-scattering/sound-absorbing segmented liner system and method

    NASA Technical Reports Server (NTRS)

    Rice, Edward J. (Inventor); Walker, Bruce E. (Inventor); Hersh, Alan S. (Inventor)

    1999-01-01

    A hybrid mode-scattering/sound-absorbing segmented liner system and method in which an initial sound field within a duct is steered or scattered into higher-order modes in a first mode-scattering segment such that it is more readily and effectively absorbed in a second sound-absorbing segment. The mode-scattering segment is preferably a series of active control components positioned along the annulus of the duct, each of which includes a controller and a resonator into which a piezoelectric transducer generates the steering noise. The sound-absorbing segment is positioned acoustically downstream of the mode-scattering segment, and preferably comprises a honeycomb-backed passive acoustic liner. The invention is particularly adapted for use in turbofan engines, both in the inlet and exhaust.

  2. Sounds like Team Spirit

    NASA Technical Reports Server (NTRS)

    Hoffman, Edward

    2002-01-01

    I recently accompanied my son Dan to one of his guitar lessons. As I sat in a separate room, I focused on the music he was playing and the beautiful, robust sound that comes from a well-played guitar. Later that night, I woke up around 3 am. I tend to have my best thoughts at this hour. The trouble is I usually roll over and fall back asleep. This time I was still awake an hour later, so I got up and jotted some notes down in my study. I was thinking about the pure, honest sound of a well-played instrument. From there my mind wandered into the realm of high-performance teams and successful projects. (I know this sounds weird, but this is the sort of thing I think about at 3 am. Maybe you have your own weird thoughts around that time.) Consider a team in relation to music. It seems to me that a crack team can achieve a beautiful, perfect unity in the same way that a band of brilliant musicians can when they're in harmony with one another. With more than a little satisfaction I have to admit, I started to think about the great work performed for you by the Knowledge Sharing team, including this magazine you are reading. Over the past two years I personally have received some of my greatest pleasures as the APPL Director from the Knowledge Sharing activities - the Masters Forums, NASA Center visits, ASK Magazine. The Knowledge Sharing team expresses such passion for their work, just like great musicians convey their passion in the music they play. In the case of Knowledge Sharing, there are many factors that have made this so enjoyable (and hopefully worthwhile for NASA). Three ingredients come to mind -- ingredients that have produced a signature sound. First, through the crazy, passionate playing of Alex Laufer, Michelle Collins, Denise Lee, and Todd Post, I always know that something startling and original is going to come out of their activities. This team has consistently done things that are unique and innovative. For me, best of all is that they are always

  3. Guide to good practices for control area activities

    SciTech Connect

    1998-12-01

    This Guide to Good Practices is written to enhance understanding of, and provide direction for, Control Area Activities, Chapter III of Department of Energy (DOE) Order 5480.19, Conduct of Operations Requirements for DOE Facilities. The practices in this guide should be considered for controlling the activities in control areas. Contractors are advised to adopt procedures that meet the intent of DOE Order 5480.19. Control Area Activities is an element of an effective Conduct of Operations program. The complexity and array of activities performed in DOE facilities dictate the necessity for maintaining a formal environment in operational control areas to promote safe and efficient operations.

  4. Improved methodology for surface and atmospheric soundings, error estimates, and quality control procedures: the atmospheric infrared sounder science team version-6 retrieval algorithm

    NASA Astrophysics Data System (ADS)

    Susskind, Joel; Blaisdell, John M.; Iredell, Lena

    2014-01-01

    The atmospheric infrared sounder (AIRS) science team version-6 AIRS/advanced microwave sounding unit (AMSU) retrieval algorithm is now operational at the Goddard Data and Information Services Center (DISC). AIRS version-6 level-2 products are generated near real time at the Goddard DISC and all level-2 and level-3 products are available starting from September 2002. Some of the significant improvements in retrieval methodology contained in the version-6 retrieval algorithm compared to that previously used in version-5 are described. In particular, the AIRS science team made major improvements with regard to the algorithms used to (1) derive surface skin temperature and surface spectral emissivity; (2) generate the initial state used to start the cloud clearing and retrieval procedures; and (3) derive error estimates and use them for quality control. Significant improvements have also been made in the generation of cloud parameters. In addition to the basic AIRS/AMSU mode, version-6 also operates in an AIRS only (AO) mode, which produces results almost as good as those of the full AIRS/AMSU mode. The improvements of some AIRS version-6 and version-6 AO products compared to those obtained using version-5 are also demonstrated.

  5. International Congress on Recent Developments in Air- and Structure-Borne Sound and Vibration, 2nd, Auburn Univ., AL, Mar. 4-6, 1992, Proceedings. Vols. 1-3

    NASA Technical Reports Server (NTRS)

    Crocker, Malcolm J. (Editor); Raju, P. K. (Editor)

    1992-01-01

    The papers presented in this volume cover a variety of topics, including sound intensity, structural intensity, modal analysis and synthesis, statistical energy analysis and energy methods, passive and active damping, and boundary element methods. Attention is also given to diagnostics and condition monitoring, material characterization and nondestructive evaluation, active noise and vibration control, sound radiation and scattering, and finite element analysis.

  6. International Congress on Recent Developments in Air- and Structure-Borne Sound and Vibration, 2nd, Auburn Univ., AL, Mar. 4-6, 1992, Proceedings. Vols. 1-3

    NASA Astrophysics Data System (ADS)

    Crocker, Malcolm J.; Raju, P. K.

    The papers presented in this volume cover a variety of topics, including sound intensity, structural intensity, modal analysis and synthesis, statistical energy analysis and energy methods, passive and active damping, and boundary element methods. Attention is also given to diagnostics and condition monitoring, material characterization and nondestructive evaluation, active noise and vibration control, sound radiation and scattering, and finite element analysis.

  7. Priming Gestures with Sounds

    PubMed Central

    Lemaitre, Guillaume; Heller, Laurie M.; Navolio, Nicole; Zúñiga-Peñaranda, Nicolas

    2015-01-01

    We report a series of experiments about a little-studied type of compatibility effect between a stimulus and a response: the priming of manual gestures via sounds associated with these gestures. The goal was to investigate the plasticity of the gesture-sound associations mediating this type of priming. Five experiments used a primed choice-reaction task. Participants were cued by a stimulus to perform response gestures that produced response sounds; those sounds were also used as primes before the response cues. We compared arbitrary associations between gestures and sounds (key lifts and pure tones) created during the experiment (i.e. no pre-existing knowledge) with ecological associations corresponding to the structure of the world (tapping gestures and sounds, scraping gestures and sounds) learned through the entire life of the participant (thus existing prior to the experiment). Two results were found. First, the priming effect exists for ecological as well as arbitrary associations between gestures and sounds. Second, the priming effect is greatly reduced for ecologically existing associations and is eliminated for arbitrary associations when the response gesture stops producing the associated sounds. These results provide evidence that auditory-motor priming is mainly created by rapid learning of the association between sounds and the gestures that produce them. Auditory-motor priming is therefore mediated by short-term associations between gestures and sounds that can be readily reconfigured regardless of prior knowledge. PMID:26544884

  8. Active parallel redundancy for electronic integrator-type control circuits

    NASA Technical Reports Server (NTRS)

    Peterson, R. A.

    1971-01-01

    Circuit extends concept of redundant feedback control from type-0 to type-1 control systems. Inactive channels are slaves to the active channel, if latter fails, it is rejected and slave channel is activated. High reliability and elimination of single-component catastrophic failure are important in closed-loop control systems.

  9. Modeling the Benchmark Active Control Technology Wind-Tunnel Model for Active Control Design Applications

    NASA Technical Reports Server (NTRS)

    Waszak, Martin R.

    1998-01-01

    This report describes the formulation of a model of the dynamic behavior of the Benchmark Active Controls Technology (BACT) wind tunnel model for active control design and analysis applications. The model is formed by combining the equations of motion for the BACT wind tunnel model with actuator models and a model of wind tunnel turbulence. The primary focus of this report is the development of the equations of motion from first principles by using Lagrange's equations and the principle of virtual work. A numerical form of the model is generated by making use of parameters obtained from both experiment and analysis. Comparisons between experimental and analytical data obtained from the numerical model show excellent agreement and suggest that simple coefficient-based aerodynamics are sufficient to accurately characterize the aeroelastic response of the BACT wind tunnel model. The equations of motion developed herein have been used to aid in the design and analysis of a number of flutter suppression controllers that have been successfully implemented.

  10. Adaptive beam-width control of echolocation sounds by CF-FM bats, Rhinolophus ferrumequinum nippon, during prey-capture flight.

    PubMed

    Matsuta, Naohiro; Hiryu, Shizuko; Fujioka, Emyo; Yamada, Yasufumi; Riquimaroux, Hiroshi; Watanabe, Yoshiaki

    2013-04-01

    The echolocation sounds of Japanese CF-FM bats (Rhinolophus ferrumequinum nippon) were measured while the bats pursued a moth (Goniocraspidum pryeri) in a flight chamber. Using a 31-channel microphone array system, we investigated how CF-FM bats adjust pulse direction and beam width according to prey position. During the search and approach phases, the horizontal and vertical beam widths were ±22±5 and ±13±5 deg, respectively. When bats entered the terminal phase approximately 1 m from a moth, distinctive evasive flight by G. pryeri was sometimes observed. Simultaneously, the bats broadened the beam widths of some emissions in both the horizontal (44% of emitted echolocation pulses) and vertical planes (71%). The expanded beam widths were ±36±7 deg (horizontal) and ±30±9 deg (vertical). When moths began evasive flight, the tracking accuracy decreased compared with that during the approach phase. However, in 97% of emissions during the terminal phase, the beam width was wider than the misalignment (the angular difference between the pulse and target directions). These findings indicate that bats actively adjust their beam width to retain the moving target within a spatial echolocation window during the final capture stages.

  11. Sound field measurement in a double layer cavitation cluster by rugged miniature needle hydrophones.

    PubMed

    Koch, Christian

    2016-03-01

    During multi-bubble cavitation the bubbles tend to organize themselves into clusters and thus the understanding of properties and dynamics of clustering is essential for controlling technical applications of cavitation. Sound field measurements are a potential technique to provide valuable experimental information about the status of cavitation clouds. Using purpose-made, rugged, wide band, and small-sized needle hydrophones, sound field measurements in bubble clusters were performed and time-dependent sound pressure waveforms were acquired and analyzed in the frequency domain up to 20 MHz. The cavitation clusters were synchronously observed by an electron multiplying charge-coupled device (EMCCD) camera and the relation between the sound field measurements and cluster behaviour was investigated. Depending on the driving power, three ranges could be identified and characteristic properties were assigned. At low power settings no transient and no or very low stable cavitation activity can be observed. The medium range is characterized by strong pressure peaks and various bubble cluster forms. At high power a stable double layer was observed which grew with further increasing power and became quite dynamic. The sound field was irregular and the fundamental at driving frequency decreased. Between the bubble clouds completely different sound field properties were found in comparison to those in the cloud where the cavitation activity is high. In between the sound field pressure amplitude was quite small and no collapses were detected.

  12. Optimal cooperative control synthesis of active displays

    NASA Technical Reports Server (NTRS)

    Garg, S.; Schmidt, D. K.

    1986-01-01

    The utility of augmenting displays to aid the human operator in controlling high order complex systems is well known. Analytical evaluation of various display designs for a simple k/s sup 2 plant in a compensatory tracking task using an optimal Control Model (OCM) of human behavior is carried out. This analysis reveals that significant improvement in performance should be obtained by skillful integration of key information into the display dynamics. The cooperative control synthesis technique previously developed to design pilot-optimal control augmentation is extended to incorporate the simultaneous design of performance enhancing augmented displays. The application of the cooperative control synthesis technique to the design of augmented displays is discussed for the simple k/s sup 2 plant. This technique is intended to provide a systematic approach to design optimally augmented displays tailored for specific tasks.

  13. Optimal cooperative control synthesis of active displays

    NASA Technical Reports Server (NTRS)

    Gary, Sanjay; Schmidt, David K.

    1987-01-01

    A technique is developed that is intended to provide a systematic approach to synthesizing display augmentation for optimal manual control in complex, closed-loop tasks. A cooperative control synthesis technique, previously developed to design pilot-optimal control augmentation for the plant, is extended to incorporate the simultaneous design of performance enhancing displays. The technique utilizes an optimal control model of the man in the loop. It is applied to the design of a quickening control law for a display and a simple K/(s squared) plant, and then to an F-15 type aircraft in a multichannel task. Utilizing the closed-loop modeling and analysis procedures, the results from the display design algorithm are evaluated and an analytical validation is performed. Experimental validation is recommended for future efforts.

  14. Optimal cooperative control synthesis of active displays

    NASA Technical Reports Server (NTRS)

    Garg, S.; Schmidt, D. K.

    1985-01-01

    The utility of augmenting displays to aid the human operator in controlling high order complex systems is well known. Analytical evaluations of various display designs for a simple k/s-squared plant in a compensatory tracking task using an Optimal Control Model (OCM) of human behavior is carried out. This analysis reveals that significant improvement in performance should be obtained by skillful integration of key information into the display dynamics. The cooperative control synthesis technique previously developed to design pilot-optimal control augmentation is extended to incorporate the simultaneous design of performance enhancing augmented displays. The application of the cooperative control synthesis technique to the design of augmented displays is discussed for the simple k/s-squared plant. This technique is intended to provide a systematic approach to design optimally augmented displays tailored for specific tasks.

  15. Optimal cooperative control synthesis of active displays

    NASA Technical Reports Server (NTRS)

    Garg, S.; Schmidt, D. K.

    1985-01-01

    A technique is developed that is intended to provide a systematic approach to synthesizing display augmentation for optimal manual control in complex, closed-loop tasks. A cooperative control synthesis technique, previously developed to design pilot-optimal control augmentation for the plant, is extended to incorporate the simultaneous design of performance enhancing displays. The technique utilizes an optimal control model of the man in the loop. It is applied to the design of a quickening control law for a display and a simple K/s(2) plant, and then to an F-15 type aircraft in a multi-channel task. Utilizing the closed loop modeling and analysis procedures, the results from the display design algorithm are evaluated and an analytical validation is performed. Experimental validation is recommended for future efforts.

  16. Visual Presentation Effects on Identification of Multiple Environmental Sounds

    PubMed Central

    Masakura, Yuko; Ichikawa, Makoto; Shimono, Koichi; Nakatsuka, Reio

    2016-01-01

    This study examined how the contents and timing of a visual stimulus affect the identification of mixed sounds recorded in a daily life environment. For experiments, we presented four environment sounds as auditory stimuli for 5 s along with a picture or a written word as a visual stimulus that might or might not denote the source of one of the four sounds. Three conditions of temporal relations between the visual stimuli and sounds were used. The visual stimulus was presented either: (a) for 5 s simultaneously with the sound; (b) for 5 s, 1 s before the sound (SOA between the audio and visual stimuli was 6 s); or (c) for 33 ms, 1 s before the sound (SOA was 1033 ms). Participants reported all identifiable sounds for those audio–visual stimuli. To characterize the effects of visual stimuli on sound identification, the following were used: the identification rates of sounds for which the visual stimulus denoted its sound source, the rates of other sounds for which the visual stimulus did not denote the sound source, and the frequency of false hearing of a sound that was not presented for each sound set. Results of the four experiments demonstrated that a picture or a written word promoted identification of the sound when it was related to the sound, particularly when the visual stimulus was presented for 5 s simultaneously with the sounds. However, a visual stimulus preceding the sounds had a benefit only for the picture, not for the written word. Furthermore, presentation with a picture denoting a sound simultaneously with the sound reduced the frequency of false hearing. These results suggest three ways that presenting a visual stimulus affects identification of the auditory stimulus. First, activation of the visual representation extracted directly from the picture promotes identification of the denoted sound and suppresses the processing of sounds for which the visual stimulus did not denote the sound source. Second, effects based on processing of the

  17. Multichannel active noise control system for local spectral reshaping of multifrequency noise

    NASA Astrophysics Data System (ADS)

    de Diego, M.; Gonzalez, A.; Ferrer, M.; Piñero, G.

    2004-07-01

    This paper discusses the development of a multichannel active system for local spectral reshaping of multitone noise. The aim of this work is to design a real practical system that performs well in local active noise control (ANC) applications, and so improving the comfort sensation produced by enclosed sound fields. The adaptive algorithm implemented in the controller is a multichannel extension of the multifrequency adaptive equalizer developed by Kuo. The philosophy behind these equalizers lies in independently controlling some given frequencies of a primary signal. Moreover, the algorithm should manage to generate usefully sized zones of equalization in order to allow for the head motion of somebody with restricted mobility; for example, a passenger seated in a car. To verify the successful implementation of the multichannel system, experiments were carried out under listening room conditions. The developed prototype consists of an array of up to four microphones used as error sensors and two secondary sources. A 4100-type Bruel and Kjaer mannequin with two calibrated microphones at the ear canals was used to measure sound levels in a hypothetical listener's head. Different synthesized repetitive noises were used, as reference signals, specifically repetitive noise with harmonics of 15, 20, and 28 Hz, as well as an 80 Hz single tone. The equalized points include an area around the error sensor positions, and these are measured using the mannequin and an x- y moving platform. The extent to which the experimental equalization zones obtained favourable results validates the multichannel local ANC equalization system. Different error sensor positions around the listener head were also tested. The residual field inside the equalization zone was measured in all cases.

  18. Active Combustion Control for Aircraft Gas Turbine Engines

    NASA Technical Reports Server (NTRS)

    DeLaat, John C.; Breisacher, Kevin J.; Saus, Joseph R.; Paxson, Daniel E.

    2000-01-01

    Lean-burning combustors are susceptible to combustion instabilities. Additionally, due to non-uniformities in the fuel-air mixing and in the combustion process, there typically exist hot areas in the combustor exit plane. These hot areas limit the operating temperature at the turbine inlet and thus constrain performance and efficiency. Finally, it is necessary to optimize the fuel-air ratio and flame temperature throughout the combustor to minimize the production of pollutants. In recent years, there has been considerable activity addressing Active Combustion Control. NASA Glenn Research Center's Active Combustion Control Technology effort aims to demonstrate active control in a realistic environment relevant to aircraft engines. Analysis and experiments are tied to aircraft gas turbine combustors. Considerable progress has been shown in demonstrating technologies for Combustion Instability Control, Pattern Factor Control, and Emissions Minimizing Control. Future plans are to advance the maturity of active combustion control technology to eventual demonstration in an engine environment.

  19. PARTICULATE EMISSION MEASUREMENTS FROM CONTROLLED CONSTRUCTION ACTIVITIES

    EPA Science Inventory

    The report summarized the results of field testing of the effectiveness of control measures for sources of fugitive particulate emissions found at construction sites. The effectiveness of watering temporary, unpaved travel surfaces on emissions of particulate matter with aerodyna...

  20. 15. INTERIOR OVERVIEW TO SOUTHEAST. ACTIVE CONTROL PANEL AND GENERATORS ...

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

    15. INTERIOR OVERVIEW TO SOUTHEAST. ACTIVE CONTROL PANEL AND GENERATORS AT LEFT, HISTORIC CONTROL PANEL AT RIGHT. - Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San Bernardino County, CA

  1. Active control of flexural vibrations in beams

    NASA Technical Reports Server (NTRS)

    Gerhold, Carl H.

    1987-01-01

    The feasibility of using piezoelectric actuators to control the flexural oscillations of large structures in space is investigated. Flexural oscillations are excited by impulsive loads. The vibratory response can degrade the pointing accuracy of cameras and antennae, and can cause high stresses at structural node points. Piezoelectric actuators have the advantage of exerting localized bending moments. In this way, vibration is controlled without exciting rigid body modes. The actuators are used in collocated sensor/driver pairs to form a feedback control system. The sensor produces a voltage that is proportional to the dynamic stress at the sensor location, and the driver produces a force that is proportional to the voltage applied to it. The analog control system amplifies and phase shifts the sensor signal to produce the voltage signal that is applied to the driver. The feedback control is demonstrated to increase the first mode damping in a cantilever beam by up to 100 percent, depending on the amplifier gain. The damping efficiency of the control system when the piezoelectrics are not optimally positioned at points of high stress in the beam is evaluated.

  2. Active chatter control in a milling machine

    SciTech Connect

    Dohner, J.L.; Hinnerichs, T.D.; Lauffer, J.P.

    1997-08-01

    The use of active feedback compensation to mitigate cutting instabilities in an advanced milling machine is discussed in this paper. A linear structural model delineating dynamics significant to the onset of cutting instabilities was combined with a nonlinear cutting model to form a dynamic depiction of an existing milling machine. The model was validated with experimental data. Modifications made to an existing machine model were used to predict alterations in dynamics due to the integration of active feedback compensation. From simulations, subcomponent requirements were evaluated and cutting enhancements were predicted. Active compensation was shown to enable more than double the metal removal rate over conventional milling machines. 25 refs., 10 figs., 1 tab.

  3. Sounding Rocket Observations of Active Region Soft X-Ray Spectra Between 0.5 and 2.5 nm Using a Modified SDO/EVE Instrument

    NASA Astrophysics Data System (ADS)

    Wieman, Seth; Didkovsky, Leonid; Woods, Thomas; Jones, Andrew; Moore, Christopher

    2016-10-01

    Spectrally resolved measurements of individual solar active regions (ARs) in the soft X-ray (SXR) range are important for studying dynamic processes in the solar corona and their associated effects on the Earth's upper atmosphere. They are also a means of evaluating atomic data and elemental abundances used in physics-based solar spectral models. However, very few such measurements are available. We present spectral measurements of two individual ARs in the 0.5 to 2.5 nm range obtained on the NASA 36.290 sounding rocket flight of 21 October 2013 (at about 18:30 UT) using the Solar Aspect Monitor (SAM), a channel of the Extreme Ultaviolet Variability Experiment (EVE) payload designed for underflight calibrations of the orbital EVE on the Solar Dynamics Observatory (SDO). The EVE rocket instrument is a duplicate of the EVE on SDO, except the SAM channel on the rocket version was modified in 2012 to include a freestanding transmission grating to provide spectrally resolved images of the solar disk with the best signal to noise ratio for the brightest features, such as ARs. Calibrations of the EVE sounding rocket instrument at the National Institute of Standards and Technology Synchrotron Ultraviolet Radiation Facility (NIST/SURF) have provided a measurement of the SAM absolute spectral response function and a mapping of wavelength separation in the grating diffraction pattern. We discuss techniques (incorporating the NIST/SURF data) for determining SXR spectra from the dispersed AR images as well as the resulting spectra for NOAA ARs 11877 and 11875 observed on the 2013 rocket flight. In comparisons with physics-based spectral models using the CHIANTI v8 atomic database we find that both AR spectra are in good agreement with isothermal spectra (4 MK), as well as spectra based on an AR differential emission measure (DEM) included with the CHIANTI distribution, with the exception of the relative intensities of strong Fe xvii lines associated with 2p6- 2p53{s} and 2p6- 2

  4. Impact of Sound Exposure and Aging on Brain-Derived Neurotrophic Factor and TrkB Receptors Levels in Dorsal Cochlear Nucleus 80 Days Following Sound Exposure

    PubMed Central

    Wang, Hongning; Brozoski, Thomas J.; Ling, Lynne; Hughes, Larry F.; Caspary, Donald M.

    2010-01-01

    Recent studies suggested that acute sound exposure resulting in a temporary threshold shift in young adult animals within a series of maladaptive plasticity changes in central auditory structures. Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, is involved in post-trauma peripheral hair cell and spiral ganglion cell survival and has been shown to modulate synaptic strength in cochlear nucleus following sound exposure. The present study evaluated levels of BDNF and its receptor (tyrosine kinase B, [TrkB]) in the dorsal cochlear nucleus (DCN) following a unilateral moderate sound exposure in young (7–8 months) and aged (28–29 months) Fischer Brown Norway (FBN) rats. Eighty days post-exposure, ABR thresholds for young exposed rats approached control values while aged exposed rats showed residual permanent threshold shifts relative to aged controls. BDNF protein levels were significantly up-regulated by 9% in young exposed fusiform cells ipsilateral to the exposure. BDNF levels in aged sound-exposed fusiform cells increased 31% ipsilateral to the exposure. Protein levels of the BDNF receptor, TrkB, were also significantly increased in aged but not in young sound-exposed DCN fusiform cells. The present findings suggest a relationship between the up-regulation of BDNF/TrkB and the increase in spontaneous and driven activity previously observed for aged and sound-exposed fusiform cells. This might be due to a selective maladaptive compensatory down-regulation of glycinergic inhibition in DCN fusiform cells. PMID:21034795

  5. 40 CFR 205.54-2 - Sound data acquisition system.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Sound data acquisition system. 205.54... ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Medium and Heavy Trucks § 205.54-2 Sound... established as equivalent to a Type I—ANSI S1.4-1971 sound level meter for use in determining compliance...

  6. Mapping Symbols to Sounds: Electrophysiological Correlates of the Impaired Reading Process in Dyslexia

    PubMed Central

    Widmann, Andreas; Schröger, Erich; Tervaniemi, Mari; Pakarinen, Satu; Kujala, Teija

    2012-01-01

    Dyslexic and control first-grade school children were compared in a Symbol-to-Sound matching test based on a non-linguistic audiovisual training which is known to have a remediating effect on dyslexia. Visual symbol patterns had to be matched with predicted sound patterns. Sounds incongruent with the corresponding visual symbol (thus not matching the prediction) elicited the N2b and P3a event-related potential (ERP) components relative to congruent sounds in control children. Their ERPs resembled the ERP effects previously reported for healthy adults with this paradigm. In dyslexic children, N2b onset latency was delayed and its amplitude significantly reduced over left hemisphere whereas P3a was absent. Moreover, N2b amplitudes significantly correlated with the reading skills. ERPs to sound changes in a control condition were unaffected. In addition, correctly predicted sounds, that is, sounds that are congruent with the visual symbol, elicited an early induced auditory gamma band response (GBR) reflecting synchronization of brain activity in normal-reading children as previously observed in healthy adults. However, dyslexic children showed no GBR. This indicates that visual symbolic and auditory sensory information are not integrated into a unitary audiovisual object representation in them. Finally, incongruent sounds were followed by a later desynchronization of brain activity in the gamma band in both groups. This desynchronization was significantly larger in dyslexic children. Although both groups accomplished the task successfully remarkable group differences in brain responses suggest that normal-reading children and dyslexic children recruit (partly) different brain mechanisms when solving the task. We propose that abnormal ERPs and GBRs in dyslexic readers indicate a deficit resulting in a widespread impairment in processing and integrating auditory and visual information and contributing to the reading impairment in dyslexia. PMID:22403564

  7. Performance of an Active Noise Control System for Fan Tones Using Vane Actuators

    NASA Technical Reports Server (NTRS)

    Sutliff, Daniel L.; Curtis, Alan R. D.; Heidelberg, Laurence J.; Remington, Paul J.

    2000-01-01

    An Active Noise Control (ANC) system for ducted fan noise was built that uses actuators located in stator vanes. The custom designed actuators A,ere piezoelectric benders manufactured using THUNDER technology. The ANC system was tested in the NASA Active Noise Control Fan rig. A total of 168 actuators in 28 stator vanes were used (six per vane). Simultaneous inlet and exhaust acoustic power level reductions were demonstrated for a fan modal structure that contained two radial modes in each direction. Total circumferential mode power levels were reduced by up to 9 dB in the inlet and 3 dB in the exhaust. The corresponding total 2BPF tone level reductions were by 6 dB in the inlet and 2 dB in the exhaust. Farfield sound pressure level reductions of up to 17 dB were achieved at the peak mode lobe angle. The performance of the system was limited by the constraints of the power amplifiers and the presence of control spillover. Simpler control/actuator systems using carefully selected subsets of the full system and random simulated failures of up to 7% of the actuators were investigated. (The actuators were robust and none failed during the test). Useful reductions still occurred under these conditions.

  8. Differential pathologies resulting from sound exposure: Tinnitus vs hearing loss

    NASA Astrophysics Data System (ADS)

    Longenecker, Ryan James

    The first step in identifying the mechanism(s) responsible for tinnitus development would be to discover a neural correlate that is differentially expressed in tinnitus-positive compared to tinnitus negative animals. Previous research has identified several neural correlates of tinnitus in animals that have tested positive for tinnitus. However it is unknown whether all or some of these correlates are linked to tinnitus or if they are a byproduct of hearing loss, a common outcome of tinnitus induction. Abnormally high spontaneous activity has frequently been linked to tinnitus. However, while some studies demonstrate that hyperactivity positively correlates with behavioral evidence of tinnitus, others show that when all animals develop hyperactivity to sound exposure, not all exposed animals show evidence of tinnitus. My working hypothesis is that certain aspects of hyperactivity are linked to tinnitus while other aspects are linked to hearing loss. The first specific aim utilized the gap induced prepulse inhibition of the acoustic startle reflex (GIPAS) to monitor the development of tinnitus in CBA/CaJ mice during one year following sound exposure. Immediately after sound exposure, GIPAS testing revealed widespread gap detection deficits across all frequencies, which was likely due to temporary threshold shifts. However, three months after sound exposure these deficits were limited to a narrow frequency band and were consistently detected up to one year after exposure. This suggests the development of chronic tinnitus is a long lasting and highly dynamic process. The second specific aim assessed hearing loss in sound exposed mice using several techniques. Acoustic brainstem responses recorded initially after sound exposure reveal large magnitude deficits in all exposed mice. However, at the three month period, thresholds return to control levels in all mice suggesting that ABRs are not a reliable tool for assessing permanent hearing loss. Input/output functions of

  9. Pulley With Active Antifriction Actuator And Control

    NASA Technical Reports Server (NTRS)

    Ih, Che-Hang C.; Vivian, Howard C.

    1994-01-01

    Torque actuator and associated control system minimizes effective friction of rotary bearing. Motor exerts compensating torque in response to feedback from external optical sensor. Compensation torque nearly cancels frictional torque of shaft bearings. Also useful in reducing bearing friction in gyro-scopes, galvanometers, torquemeters, accelerometers, earth-motion detectors, and balances.

  10. Selective Activation and Disengagement of Moral Control.

    ERIC Educational Resources Information Center

    Bandura, Albert

    1990-01-01

    Analyzes psychological mechanisms by which moral control is selectively disengaged from inhumane conduct in ordinary and unusual circumstances. Explores the symptoms of moral exclusion as described in the literature. Presents categories that unify theory on moral exclusion and contribute practical classifications for use in empirical studies. (JS)

  11. Rainsticks: Integrating Culture, Folklore, and the Physics of Sound

    ERIC Educational Resources Information Center

    Moseley, Christine; Fies, Carmen

    2007-01-01

    The purpose of this activity is for students to build a rainstick out of materials in their own environment and imitate the sound of rain while investigating the physical principles of sound. Students will be able to relate the sound produced by an instrument to the type and quantity of materials used in its construction.

  12. Insula and inferior frontal triangularis activations distinguish between conditioned brain responses using emotional sounds for basic BCI communication

    PubMed Central

    van der Heiden, Linda; Liberati, Giulia; Sitaram, Ranganatha; Kim, Sunjung; Jaśkowski, Piotr; Raffone, Antonino; Olivetti Belardinelli, Marta; Birbaumer, Niels; Veit, Ralf

    2014-01-01

    In order to enable communication through a brain-computer interface (BCI), it is necessary to discriminate between distinct brain responses. As a first step, we probed the possibility to discriminate between affirmative (“yes”) and negative (“no”) responses using a semantic classical conditioning paradigm, within an fMRI setting. Subjects were presented with congruent and incongruent word-pairs as conditioned stimuli (CS), respectively eliciting affirmative and negative responses. Incongruent word-pairs were associated to an unpleasant unconditioned stimulus (scream, US1) and congruent word-pairs were associated to a pleasant unconditioned stimulus (baby-laughter, US2), in order to elicit emotional conditioned responses (CR). The aim was to discriminate between affirmative and negative responses, enabled by their association with the positive and negative affective stimuli. In the late acquisition phase, when the US were not present anymore, there was a strong significant differential activation for incongruent and congruent word-pairs in a cluster comprising the left insula and the inferior frontal triangularis. This association was not found in the habituation phase. These results suggest that the difference in affirmative and negative brain responses was established as an effect of conditioning, allowing to further investigate the possibility of using this paradigm for a binary choice BCI. PMID:25100958

  13. Immediate effect of mind sound resonance technique on state anxiety and cognitive functions in patients suffering from generalized anxiety disorder: A self-controlled pilot study

    PubMed Central

    Dhansoia, Vipin; Bhargav, Hemant; Metri, Kashinath

    2015-01-01

    Objectives: To compare the immediate effect of mind sound resonance technique (MSRT) with supine rest (SR) on state anxiety and psychomotor performance in 15 (eight male and seven female) right-handed generalized anxiety disorder patients (GAD) with an age range of 34.8 ± 12.8 years. Materials and Methods: Self as control design was followed. Diagnosis of GAD was made by a psychiatrist using sections of the Mini International Neuropsychiatric Interview (MINI). Participants practiced MSRT or SR (as control intervention) for 30 min at the same time for two consecutive days. The sequence of intervention was assigned randomly to the participants. State anxiety was assessed using state trait anxiety inventory (STAI; Form X1). Digit letter substitution task (DLST) was used to assess psychomotor performance, which involves visual scanning, mental flexibility, sustained attention, psychomotor speed and speed of information processing. Intervention was given in a quiet dark room on an empty stomach. Subjects received a training of MSRT and SR for 1 week before the data were taken. A pre-recorded audiotape was used to administer the technique of MSRT. Difference in scores after baseline and intervention was used to check normality, and was found to be normally distributed by the Kolmogrov–Smirnov test. The changes in STAI, DLST and difference in scores before and after two interventions (MSRT and SR) were compared using the paired samples t test. Results: As compared with baseline, STAI scores reduced and DLST scores increased significantly (STAI; P < 0.01; DLST; P < 0.01) after MSRT. After SR, there was a significant reduction in STAI scores from baseline (STAI; P < 0.05), but there was no significant change in the DLST scores (P = 0.26). Comparison of the difference in scores for DLST and STAI before and after the two interventions (MSRT and SR) showed a significantly higher score for DLST (P < 0.05) and a significantly lower score for STAI (P < 0.01) for MSRT as

  14. Genetic Control of Active Neural Circuits

    PubMed Central

    Reijmers, Leon; Mayford, Mark

    2009-01-01

    The use of molecular tools to study the neurobiology of complex behaviors has been hampered by an inability to target the desired changes to relevant groups of neurons. Specific memories and specific sensory representations are sparsely encoded by a small fraction of neurons embedded in a sea of morphologically and functionally similar cells. In this review we discuss genetics techniques that are being developed to address this difficulty. In several studies the use of promoter elements that are responsive to neural activity have been used to drive long-lasting genetic alterations into neural ensembles that are activated by natural environmental stimuli. This approach has been used to examine neural activity patterns during learning and retrieval of a memory, to examine the regulation of receptor trafficking following learning and to functionally manipulate a specific memory trace. We suggest that these techniques will provide a general approach to experimentally investigate the link between patterns of environmentally activated neural firing and cognitive processes such as perception and memory. PMID:20057936

  15. Abnormal cortical sensorimotor activity during “Target” sound detection in subjects with acute acoustic trauma sequelae: an fMRI study

    PubMed Central

    Job, Agnès; Pons, Yoann; Lamalle, Laurent; Jaillard, Assia; Buck, Karl; Segebarth, Christoph; Delon-Martin, Chantal

    2012-01-01

    The most common consequences of acute acoustic trauma (AAT) are hearing loss at frequencies above 3 kHz and tinnitus. In this study, we have used functional Magnetic Resonance Imaging (fMRI) to visualize neuronal activation patterns in military adults with AAT and various tinnitus sequelae during an auditory “oddball” attention task. AAT subjects displayed overactivities principally during reflex of target sound detection, in sensorimotor areas and in emotion-related areas such as the insula, anterior cingulate and prefrontal cortex, in premotor area, in cross-modal sensory associative areas, and, interestingly, in a region of the Rolandic operculum that has recently been shown to be involved in tympanic movements due to air pressure. We propose further investigations of this brain area and fine middle ear investigations, because our results might suggest a model in which AAT tinnitus may arise as a proprioceptive illusion caused by abnormal excitability of middle-ear muscle spindles possibly link with the acoustic reflex and associated with emotional and sensorimotor disturbances. PMID:22574285

  16. FINAL REPORT OF FY 1999, 2000, AND 2001 ACTIVITIES: CONTINUED DEVELOPMENT OF AN INTEGRATED SOUNDING SYSTEM IN SUPPORT OF THE DOE/ARM EXPERIMENTAL PROGRAM

    SciTech Connect

    Ed R. Westwater CIRES, University of Colorado /NOAA Environmental Technology Laboratory 325 Broadway MS R/E/ET1 Boulder, Colorado 80305

    2002-04-30

    OAK B188 FINAL REPORT OF FY 1999, 2000, AND 2001 ACTIVITIES: CONTINUED DEVELOPMENT OF AN INTEGRATED SOUNDING SYSTEM IN SUPPORT OF THE DOE/ARM EXPERIMENTAL PROGRAM The basic goals of the research are to develop and test algorithms and deploy instruments that improve measurements of atmospheric quantities relevant to radiative transfer and climate research. Primary among these atmospheric variables are integrated amounts of water vapor and cloud liquid, as well as profiles of temperature, water vapor and cloud liquid. A primary thrust of this research is to combine data from instruments available to ARM to maximize their importance in radiative transfer and climate research. To gather data relevant to these studies, participation in field experiments, especially intensive operating periods, as well as the subsequent analysis and dissemination of collected data, is of primary importance. Examples of relevant experiments include several Water Vapor Intensive Operating Periods at the Southern Great Plains Cloud And Radiation Testbed site, experiments in the Tropical Western Pacific such as PROBE and Nauru'99, and experiments at the North Slope of Alaska/Adjacent Arctic Ocean site. This final report describes our analyses of data taken during these field experiments.

  17. Hearing in three dimensions: Sound localization

    NASA Technical Reports Server (NTRS)

    Wightman, Frederic L.; Kistler, Doris J.

    1990-01-01

    The ability to localize a source of sound in space is a fundamental component of the three dimensional character of the sound of audio. For over a century scientists have been trying to understand the physical and psychological processes and physiological mechanisms that subserve sound localization. This research has shown that important information about sound source position is provided by interaural differences in time of arrival, interaural differences in intensity and direction-dependent filtering provided by the pinnae. Progress has been slow, primarily because experiments on localization are technically demanding. Control of stimulus parameters and quantification of the subjective experience are quite difficult problems. Recent advances, such as the ability to simulate a three dimensional sound field over headphones, seem to offer potential for rapid progress. Research using the new techniques has already produced new information. It now seems that interaural time differences are a much more salient and dominant localization cue than previously believed.

  18. Hybrid Architecture Active Wavefront Sensing and Control

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Dean, Bruce; Hyde, Tupper

    2010-01-01

    A method was developed for performing relatively high-speed wavefront sensing and control to overcome thermal instabilities in a segmented primary mirror telescope [e.g., James Webb Space Telescope (JWST) at L2], by using the onboard fine guidance sensor (FGS) to minimize expense and complexity. This FGS performs centroiding on a bright star to feed the information to the pointing and control system. The proposed concept is to beam split the image of the guide star (or use a single defocused guide star image) to perform wavefront sensing using phase retrieval techniques. Using the fine guidance sensor star image for guiding and fine phasing eliminates the need for other, more complex ways of achieving very accurate sensing and control that is needed for UV-optical applications. The phase retrieval occurs nearly constantly, so passive thermal stability over fourteen days is not required. Using the FGS as the sensor, one can feed segment update information to actuators on the primary mirror that can update the primary mirror segment fine phasing with this frequency. Because the thermal time constants of the primary mirror are very slow compared to this duration, the mirror will appear extremely stable during observations (to the level of accuracy of the sensing and control). The sensing can use the same phase retrieval techniques as the JWST by employing an additional beam splitter, and having each channel go through a weak lens (one positive and one negative). The channels can use common or separate detectors. Phase retrieval can be performed onboard. The actuation scheme would include a coarse stage able to achieve initial alignment of several millimeters of range (similar to JWST and can use a JWST heritage sensing approach in the science camera) and a fine stage capable of continual updates.

  19. Interactive MRI Segmentation with Controlled Active Vision

    PubMed Central

    Karasev, Peter; Kolesov, Ivan; Chudy, Karol; Muller, Grant; Xerogeanes, John; Tannenbaum, Allen

    2013-01-01

    Partitioning Magnetic-Resonance-Imaging (MRI) data into salient anatomic structures is a problem in medical imaging that has continued to elude fully automated solutions. Implicit functions are a common way to model the boundaries between structures and are amenable to control-theoretic methods. In this paper, the goal of enabling a human to obtain accurate segmentations in a short amount of time and with little effort is transformed into a control synthesis problem. Perturbing the state and dynamics of an implicit function’s driving partial differential equation via the accumulated user inputs and an observer-like system leads to desirable closed-loop behavior. Using a Lyapunov control design, a balance is established between the influence of a data-driven gradient flow and the human’s input over time. Automatic segmentation is thus smoothly coupled with interactivity. An application of the mathematical methods to orthopedic segmentation is shown, demonstrating the expected transient and steady state behavior of the implicit segmentation function and auxiliary observer. PMID:24584213

  20. Active control for turbulent premixed flame simulations

    SciTech Connect

    Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.

    2004-03-26

    Many turbulent premixed flames of practical interest are statistically stationary. They occur in combustors that have anchoring mechanisms to prevent blow-off and flashback. The stabilization devices often introduce a level of geometric complexity that is prohibitive for detailed computational studies of turbulent flame dynamics. As a result, typical detailed simulations are performed in simplified model configurations such as decaying isotropic turbulence or inflowing turbulence. In these configurations, the turbulence seen by the flame either decays or, in the latter case, increases as the flame accelerates toward the turbulent inflow. This limits the duration of the eddy evolutions experienced by the flame at a given level of turbulent intensity, so that statistically valid observations cannot be made. In this paper, we apply a feedback control to computationally stabilize an otherwise unstable turbulent premixed flame in two dimensions. For the simulations, we specify turbulent in flow conditions and dynamically adjust the integrated fueling rate to control the mean location of the flame in the domain. We outline the numerical procedure, and illustrate the behavior of the control algorithm. We use the simulations to study the propagation and the local chemical variability of turbulent flame chemistry.