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Sample records for acoustic reciprocity principle

  1. The principle of reciprocity.

    PubMed

    Hoult, D I

    2011-12-01

    The circumstances surrounding the realisation that NMR signal reception could be quantified in a simple fundamental manner using Lorentz's Principle of Reciprocity are described. The poor signal-to-noise ratio of the first European superconducting magnet is identified as a major motivating factor, together with the author's need to understand phenomena at a basic level. A summary is then given of the thought processes leading to the very simple pseudo-static formula that has been the basis of signal-to-noise calculations for over a generation. PMID:21889377

  2. Reciprocity principle and crack identification

    NASA Astrophysics Data System (ADS)

    Andrieux, Stéphane; Ben Abda, Amel; Duong Bui, Huy

    1999-02-01

    In this paper we are concerned with the planar crack identification problem defined by a unique complete elastostatic overdetermined boundary datum. Based on the reciprocity gap principle, we give a direct process for locating the host plane and we establish a new constuctive identifiability result for 3D planar cracks.

  3. Non-reciprocal and highly nonlinear active acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Popa, Bogdan-Ioan; Cummer, Steven A.

    2014-02-01

    Unidirectional devices that pass acoustic energy in only one direction have numerous applications and, consequently, have recently received significant attention. However, for most practical applications that require unidirectionality at audio and low frequencies, subwavelength implementations capable of the necessary time-reversal symmetry breaking remain elusive. Here we describe a design approach based on metamaterial techniques that provides highly subwavelength and strongly non-reciprocal devices. We demonstrate this approach by designing and experimentally characterizing a non-reciprocal active acoustic metamaterial unit cell composed of a single piezoelectric membrane augmented by a nonlinear electronic circuit, and sandwiched between Helmholtz cavities tuned to different frequencies. The design is thinner than a tenth of a wavelength, yet it has an isolation factor of >10 dB. The design method generates relatively broadband unidirectional devices and is a good candidate for numerous acoustic applications.

  4. Non-reciprocal and highly nonlinear active acoustic metamaterials.

    PubMed

    Popa, Bogdan-Ioan; Cummer, Steven A

    2014-01-01

    Unidirectional devices that pass acoustic energy in only one direction have numerous applications and, consequently, have recently received significant attention. However, for most practical applications that require unidirectionality at audio and low frequencies, subwavelength implementations capable of the necessary time-reversal symmetry breaking remain elusive. Here we describe a design approach based on metamaterial techniques that provides highly subwavelength and strongly non-reciprocal devices. We demonstrate this approach by designing and experimentally characterizing a non-reciprocal active acoustic metamaterial unit cell composed of a single piezoelectric membrane augmented by a nonlinear electronic circuit, and sandwiched between Helmholtz cavities tuned to different frequencies. The design is thinner than a tenth of a wavelength, yet it has an isolation factor of >10 dB. The design method generates relatively broadband unidirectional devices and is a good candidate for numerous acoustic applications. PMID:24572771

  5. Reciprocity in the scattering coefficients of acoustic waveguide modes.

    PubMed

    Tong, Yuhui; Pan, Jie

    2013-09-01

    In this Letter, a proof is provided for the reciprocity between modal scattering coefficients of the acoustic waveguides connected by a junction enclosure. The result holds for all waveguide modes and for junction enclosures with locally reactive boundary conditions away from the interfaces between the junction and waveguides. Also provided is a physical interpretation of the reciprocity of the modal scattering coefficients. The scattering of two-dimensional waveguide modes by a right-angled bend in a rectangular duct is used as an illustrating example. PMID:23967907

  6. Transcranial Electrical Neuromodulation Based on the Reciprocity Principle.

    PubMed

    Fernández-Corazza, Mariano; Turovets, Sergei; Luu, Phan; Anderson, Erik; Tucker, Don

    2016-01-01

    A key challenge in multi-electrode transcranial electrical stimulation (TES) or transcranial direct current stimulation (tDCS) is to find a current injection pattern that delivers the necessary current density at a target and minimizes it in the rest of the head, which is mathematically modeled as an optimization problem. Such an optimization with the Least Squares (LS) or Linearly Constrained Minimum Variance (LCMV) algorithms is generally computationally expensive and requires multiple independent current sources. Based on the reciprocity principle in electroencephalography (EEG) and TES, it could be possible to find the optimal TES patterns quickly whenever the solution of the forward EEG problem is available for a brain region of interest. Here, we investigate the reciprocity principle as a guideline for finding optimal current injection patterns in TES that comply with safety constraints. We define four different trial cortical targets in a detailed seven-tissue finite element head model, and analyze the performance of the reciprocity family of TES methods in terms of electrode density, targeting error, focality, intensity, and directionality using the LS and LCMV solutions as the reference standards. It is found that the reciprocity algorithms show good performance comparable to the LCMV and LS solutions. Comparing the 128 and 256 electrode cases, we found that use of greater electrode density improves focality, directionality, and intensity parameters. The results show that reciprocity principle can be used to quickly determine optimal current injection patterns in TES and help to simplify TES protocols that are consistent with hardware and software availability and with safety constraints. PMID:27303311

  7. Transcranial Electrical Neuromodulation Based on the Reciprocity Principle

    PubMed Central

    Fernández-Corazza, Mariano; Turovets, Sergei; Luu, Phan; Anderson, Erik; Tucker, Don

    2016-01-01

    A key challenge in multi-electrode transcranial electrical stimulation (TES) or transcranial direct current stimulation (tDCS) is to find a current injection pattern that delivers the necessary current density at a target and minimizes it in the rest of the head, which is mathematically modeled as an optimization problem. Such an optimization with the Least Squares (LS) or Linearly Constrained Minimum Variance (LCMV) algorithms is generally computationally expensive and requires multiple independent current sources. Based on the reciprocity principle in electroencephalography (EEG) and TES, it could be possible to find the optimal TES patterns quickly whenever the solution of the forward EEG problem is available for a brain region of interest. Here, we investigate the reciprocity principle as a guideline for finding optimal current injection patterns in TES that comply with safety constraints. We define four different trial cortical targets in a detailed seven-tissue finite element head model, and analyze the performance of the reciprocity family of TES methods in terms of electrode density, targeting error, focality, intensity, and directionality using the LS and LCMV solutions as the reference standards. It is found that the reciprocity algorithms show good performance comparable to the LCMV and LS solutions. Comparing the 128 and 256 electrode cases, we found that use of greater electrode density improves focality, directionality, and intensity parameters. The results show that reciprocity principle can be used to quickly determine optimal current injection patterns in TES and help to simplify TES protocols that are consistent with hardware and software availability and with safety constraints. PMID:27303311

  8. Reciprocity principle for scattered fields from discontinuities in waveguides.

    PubMed

    Pau, Annamaria; Capecchi, Danilo; Vestroni, Fabrizio

    2015-01-01

    This study investigates the scattering of guided waves from a discontinuity exploiting the principle of reciprocity in elastodynamics, written in a form that applies to waveguides. The coefficients of reflection and transmission for an arbitrary mode can be derived as long as the principle of reciprocity is satisfied at the discontinuity. Two elastodynamic states are related by the reciprocity. One is the response of the waveguide in the presence of the discontinuity, with the scattered fields expressed as a superposition of wave modes. The other state is the response of the waveguide in the absence of the discontinuity oscillating according to an arbitrary mode. The semi-analytical finite element method is applied to derive the needed dispersion relation and wave mode shapes. An application to a solid cylinder with a symmetric double change of cross-section is presented. This model is assumed to be representative of a damaged rod. The coefficients of reflection and transmission of longitudinal waves are investigated for selected values of notch length and varying depth. PMID:25172113

  9. Mental health law: civil liberties and the principle of reciprocity.

    PubMed Central

    Eastman, N.

    1994-01-01

    At a conference organised by the Law Society, Mental Health Act Commission, and Institute of Psychiatry possible reform of mental health legislation in England and Wales was discussed. It was concluded that radical legal reform was required, and that the law should be designed specifically for provision of care in both hospital and the community. Reform should be based on principle rather than pragmatism, particularly the principle of reciprocity--patients' civil liberties may not be removed for the purposes of treatment if resources for that treatment are inadequate. Protection of society from nuisance or even violence is insufficient reason for detention. Legal provision for compulsion of patients, whether in hospital or the community, must be matched by specific rights to treatment. PMID:8179659

  10. Principle of reciprocity solves the most important problems in bioimpedance and in general in bioelectromagnetism

    NASA Astrophysics Data System (ADS)

    Malmivuo, Jaakko

    2010-04-01

    Though the principle of reciprocity was invented by Hermann von Helmholtz already over 150 years ago, and though it is a very powerful tool in solving various important problems in bioelectromagnetism, it is not generally used. In impedance tomography the measurement sensitivity distribution has generally been misunderstood. This can be easily demonstrated with the principle of reciprocity. Some other applications of the principle of reciprocity are also discussed.

  11. a Reverse Flow Theorem and Acoustic Reciprocity in Compressible Potential Flows in Ducts

    NASA Astrophysics Data System (ADS)

    EVERSMAN, W.

    2001-09-01

    A reverse flow theorem for acoustic propagation in compressible potential flow has been obtained directly from the field equations without recourse to energy conservation arguments. A reciprocity theorem for the scattering matrix for the propagation of acoustic modes in a duct with either acoustically rigid walls or acoustically absorbing walls follows. It is found that for a source at a specific end of the duct, suitably scaled reflection matrices in direct and reverse flow have a reciprocal relationship. Scaled transmission matrices obtained for direct flow and reversed flow with simultaneous switching of source location from one end to the other also have a reciprocal relationship. A related reverse flow theorem specialized to one-dimensional acoustic propagation has also been obtained. Reciprocity relationships for the scattering coefficients for propagation are derived, and are found to be similar though much simpler than in the case of multi-mode propagation. In one-dimensional flow, reciprocal relations and power conservation arguments are used to show that scaled power reflection and transmission coefficients are invariant to flow reversal and switching of source location from one end of the duct to the other. Numerical verification of the reciprocal relationships is given in a companion paper.

  12. Numerical Experiments on Acoustic Reciprocity in Compressible Potential Flows in Ducts

    NASA Astrophysics Data System (ADS)

    EVERSMAN, W.

    2001-09-01

    A reciprocity theorem for the scattering matrix for the propagation of acoustic modes in a duct with acoustically hard walls or with acoustically absorbing walls has been given in a companion publication. It was found that for a source at a specified end of the duct, suitably scaled reflection matrices in direct and reverse flow have a reciprocal relationship. Scaled transmission matrices obtained for direct flow and reversed flow with simultaneous switching of source location from one end to the other also have a reciprocal relationship. A reverse flow theorem for the equivalent one-dimensional propagation model, which is a good approximation to the three-dimensional model at low frequencies, was also obtained. In this case, using reciprocity and acoustic power conservation arguments it is additionally found that the acoustic power transmission coefficient is the same for a source at either end of the duct for a given flow direction. This result leads to an invariance theorem which relates acoustic power propagated due to sources of equal pressure amplitude at the two ends of the duct. A numerical verification of these reciprocal relationships is given here for propagation in axially symmetric (circular and annular) ducts with multi-modal propagation and at low frequencies when a one-dimensional model is appropriate.

  13. The acoustic simulation and analysis of complicated reciprocating compressor piping systems, I: Analysis technique and parameter matrices of acoustic elements

    NASA Astrophysics Data System (ADS)

    To, C. W. S.

    1984-09-01

    This paper describes the mathematical formulation, equations, and procedures employed in the development of a comprehensive digital computer program for acoustic simulation and analysis of large and complicated piping systems. The analysis technique used is the transfer matrix method in which the piping system, with or without multiple inputs and outputs, is represented by a combination of discrete acoustic elements interconnected to one another at two stations such that the acoustic pressure and volume velocity at one station are uniquely related to those at the other by a two-by-two parameter matrix. Parameter matrices of 19 acoustic elements are included in this paper. By making use of these parameter matrices and the analysis technique, any complicated practical reciprocating compressor piping system can be modelled or analyzed.

  14. Coherent reflection from surface gravity water waves during reciprocal acoustic transmissions.

    PubMed

    Badiey, Mohsen; Song, Aijun; Smith, Kevin B

    2012-10-01

    During a recent experiment in Kauai, Hawaii, reciprocal transmissions were conducted between two acoustic transceivers mounted on the seafloor at a depth of 100 m. The passage of moving surface wave crests was shown to generate focused and intense coherent acoustic returns, which had increasing or decreasing delay depending on the direction of propagation relative to the direction of surface wave crests. It is shown that a rough surface two-dimensional parabolic equation model with an evolving sea surface can produce qualitative agreement with data for the dynamic surface returns. PMID:23039567

  15. Acoustic Reciprocity of Spatial Coherence in Ultrasound Imaging

    PubMed Central

    Bottenus, Nick; Üstüner, Kutay F.

    2015-01-01

    A conventional ultrasound image is formed by transmitting a focused wave into tissue, time-shifting the backscattered echoes received on an array transducer and summing the resulting signals. The van Cittert-Zernike theorem predicts a particular similarity, or coherence, of these focused signals across the receiving array. Many groups have used an estimate of the coherence to augment or replace the B-mode image in an effort to suppress noise and stationary clutter echo signals, but this measurement requires access to individual receive channel data. Most clinical systems have efficient pipelines for producing focused and summed RF data without any direct way to individually address the receive channels. We describe a method for performing coherence measurements that is more accessible for a wide range of coherence-based imaging. The reciprocity of the transmit and receive apertures in the context of coherence is derived and equivalence of the coherence function is validated experimentally using a research scanner. The proposed method is implemented on a Siemens ACUSON SC2000™ultrasound system and in vivo short-lag spatial coherence imaging is demonstrated using only summed RF data. The components beyond the acquisition hardware and beamformer necessary to produce a real-time ultrasound coherence imaging system are discussed. PMID:25965679

  16. Acoustical analysis and modeling of reciprocating compressors, noise produced by gas pulsation, using four-pole method. II

    NASA Astrophysics Data System (ADS)

    Herfat, Ali T.; Seel, Robert V.

    2003-04-01

    Presented in Paper II is the noise analysis of reciprocating compressors (such as air conditioning and refrigeration reciprocating compressors) using the four-pole method. The gas pulsation noise inside compressor head cavities, mufflers, and through-valves can be analyzed by applying the FPM. This method formulates the characteristics of acoustic elements by establishing a relationship between their input and output gas pressures and volume flow rates. When the acoustic elements in the system (compressor) are connected at points between them, the FPM allows an easy assembly of element equations to obtain system acoustical model.

  17. Acoustic grazing flow impedance using waveguide principles

    NASA Technical Reports Server (NTRS)

    Armstrong, D. L.

    1971-01-01

    A grazing flow apparatus was designed to measure the impedance of acoustic materials when installed in environments that subject the material to grazing airflow. The design of the apparatus and the data analysis technique is based on the solution of the convected wave equation in an infinite length waveguide.

  18. Origami acoustics: using principles of folding structural acoustics for simple and large focusing of sound energy

    NASA Astrophysics Data System (ADS)

    Harne, Ryan L.; Lynd, Danielle T.

    2016-08-01

    Fixed in spatial distribution, arrays of planar, electromechanical acoustic transducers cannot adapt their wave energy focusing abilities unless each transducer is externally controlled, creating challenges for the implementation and portability of such beamforming systems. Recently, planar, origami-based structural tessellations are found to facilitate great versatility in system function and properties through kinematic folding. In this research we bridge the physics of acoustics and origami-based design to discover that the simple topological reconfigurations of a Miura-ori-based acoustic array yield many orders of magnitude worth of reversible change in wave energy focusing: a potential for acoustic field morphing easily obtained through deployable, tessellated architectures. Our experimental and theoretical studies directly translate the roles of folding the tessellated array to the adaptations in spectral and spatial wave propagation sensitivities for far field energy transmission. It is shown that kinematic folding rules and flat-foldable tessellated arrays collectively provide novel solutions to the long-standing challenges of conventional, electronically-steered acoustic beamformers. While our examples consider sound radiation from the foldable array in air, linear acoustic reciprocity dictates that the findings may inspire new innovations for acoustic receivers, e.g. adaptive sound absorbers and microphone arrays, as well as concepts that include water-borne waves.

  19. Scanning tomographic acoustic microscopy: principles and recent developments (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Wade, G.; Meyyappan, A.

    1987-09-01

    Acoustic Microscopy is an important branch of non-destructive evaluation which provides high resolution for imaging the detailed structure of a small object. When an acoustic microscope operates in the transmission mode, the micrograph is simply a shadowgraph of all the structures encountered by the acoustic wave passing through the object. Because of diffraction and overlapping, the resultant images are difficult to comprehend in the case of specimens of substantial thickness and structural complexity. We used the principles of diffraction tomography and acoustical holography along with digital calcuations of wavefield propagation to overcome this problem. We have described in previously-published work how a scanning laser acoustic microscope (SLAM) can be modified to obtain data for subsurface tomographic imaging. In this paper, we review the principles of scanning tomographic acoustic microscopy (STAM). The required modification of SLAM to obtain STAM and the reconstruction process are described. We show how we are able to accurately acquire the complex-amplitude information necessary for image reconstruction. We demonstrate the power of this technique by comparing digitally-computed images thus obtained with analogue images of a conventional SLAM. The results show that high-quality, high-resolution subsurface images can be obtained from experimentally acquired data. We also describe techniques to obtain projection data from different angles of wave incidence enabling us to tomographically reconstruct different planes of a complex specimen in microscopic detail. With these modifications in place, STAM should shortly become a powerful tool in non-destructive evaluation.

  20. A modal test method using sound pressure transducers based on vibro-acoustic reciprocity

    NASA Astrophysics Data System (ADS)

    Zhu, W. D.; Liu, J. M.; Xu, Y. F.; Ying, H. Q.

    2014-06-01

    A modal test method that uses sound pressure transducers at fixed locations and an impact hammer roving over a test structure is developed in this work. Since sound pressure transducers are used, the current method deals with a coupled structural-acoustic system. Based on the vibro-acoustic reciprocity, the method is equivalent to one, where acoustic excitations at fixed locations are given and the resulting acceleration of the test structure is measured. The current method can eliminate mass loading due to use of accelerometers, which can destroy existence of repeated or close natural frequencies of a symmetric structure. It can also avoid effects of a nodal line of a mode and an inactive area of a local mode, and measure all the out-of-plane modes within a frequency range of interest, including global and local ones. The coupling between the structure and the acoustic field in a structural-acoustic system introduces asymmetry in the model formulation. An equivalent state space formulation is used for a damped structural-acoustic system and the associated eigenvalue problem is derived. The biorthonormality relations between the left and right eigenvectors and the relations between the structural and acoustic components in the left and right eigenvectors are proved. The frequency response functions associated with the current method are derived and their physical meanings are explained. The guidelines for using the current method, including the types of structures that are suitable for the method, the positions of the sound pressure transducers, and the orientation of the test structure relative to the transducers, are provided. Modal tests were carried out on an automotive disk brake using the traditional and current methods, where multiple accelerometers and microphones were used to measure its dynamic responses induced by impacts, respectively. The differences between the measured natural frequencies using the current method and those from the finite element

  1. The acoustic simulation and analysis of complicated reciprocating compressor piping systems, II: Program structure and applications

    NASA Astrophysics Data System (ADS)

    To, C. W. S.

    1984-09-01

    The main objectives of the investigation reported in this paper, Part II, and its companion paper, Part I, are (a) to provide a formulation, including the mean flow effects and suitable for digital computer automation, of the acoustics of complicated piping systems, and (b) to develop a comprehensive digital computer program for the simulation and analysis of complicated reciprocating compressor piping systems. In this paper, the digital computer program structure and applications of the program developed, written in Fortran IV, are described. It is concluded that the computer program is versatile and user-friendly. It is capable of providing a great deal of information from one set of input data, and is open-ended and modular for updating.

  2. Reciprocity principle and nonequivalence of counterpropagating modes in whistle-geometry ring lasers

    NASA Astrophysics Data System (ADS)

    Kalagara, Hemashilpa; Chu, Fei-Hung; Smolyakov, Gennady A.; Osiński, Marek

    2016-03-01

    Greatly enhanced high-speed modulation performance has been recently predicted in numerical calculations for a novel injection-locking scheme involving a distributed Bragg reflector master laser monolithically integrated with a unidirectional whistle-geometry semiconductor micro ring laser. In this work, we confirm the unidirectionality of the whistle-geometry configuration through rigorous three-dimensional finite-difference time-domain (FDTD) simulation by showing a strong asymmetry in photon lifetimes between the two counter propagating modes. At the same time, we explain why this result does not violate the Helmholtz reciprocity principle.

  3. Community and job satisfactions: an argument for reciprocal influence based on the principle of stimulus generalization

    SciTech Connect

    Gavin, J.; Montgomery, J.C.

    1982-10-01

    The principle of stimulus generalization provided the underlying argument for a test of hypotheses regarding the association of community and job satisfactions and a critique of related theory and research. Two-stage least squares (2SLS) analysis made possible the examination of reciprocal causation, a notion inherent in the theoretical argument. Data were obtained from 276 employees of a Western U.S. coal mine as part of a work attitudes survey. The 2SLS analysis indicated a significant impact of community satisfaction on job satisfaction and an effect of borderline significance of job on community satisfaction. Theory-based correlational comparisons were made on groups of employees residing in four distinct communities, high and low tenure groups, males and females, and different levels in the mine's hierarchy. The pattern of correlations was generally consistent with predictions, but significance tests for differences yielded equivocal support. When considered in the context of previous studies, the data upheld a reciprocal causal model and the explanatory principle of stimulus generalization for understanding the relation of community and job satisfactions. Sample characteristics necessitate cautious interpretation and the model per se might best be viewed as a heuristic framework for more definitive research.

  4. Acoustic levitation and the Boltzmann-Ehrenfest principle

    NASA Technical Reports Server (NTRS)

    Putterman, S.; Rudnick, Joseph; Barmatz, M.

    1989-01-01

    The Boltzmann-Ehrenfest principle of adiabatic invariance relates the acoustic potential acting on a sample positioned in a single-mode cavity to the shift in resonant frequency caused by the presence of this sample. This general and simple relation applies to samples and cavities of arbitrary shape, dimension, and compressibility. Positioning forces and torques can, therefore, be determined from straightforward measurements of frequency shifts. Applications to the Rayleigh disk phenomenon and levitated cylinders are presented.

  5. The functionality of female reciprocal calls in the Iberian midwife toad (Alytes cisternasii): female-female acoustic competition?

    NASA Astrophysics Data System (ADS)

    Bosch, Jaime

    2002-11-01

    Female midwife toads (genus Alytes) emit highly variable reciprocal calls of unclear function prior to and during courtship. In some species, female-female competition, expressed as physical fighting, has been reported. Males of Majorcan midwife toads (Alytes muletensis) show phonotactic response to female calls, and females of Iberian midwife toads (Alytes cisternasii) respond differently according to the male call characteristics. In this study, I test the hypothesis of female-female acoustic competition as an additional function of female reciprocal calls. Playback tests indicate that female calls are not clearly involved in female acoustic competition in the Iberian midwife toad, therefore female calls could be directed at males rather than towards competitive females.

  6. Calculation of reciprocal velocity curves of intrinsic surface acoustic wave in quartz crystal

    NASA Astrophysics Data System (ADS)

    Liu, Tao; Yu, Kuanxin

    2010-10-01

    Quartz crystal has excellent piezoelectric properties, it can be used as substrates of surface acoustic wave (SAW) devices, for example delay line, filter, oscillator, convolver, acousto-optic (AO) device and so on. In this paper, Intrinsic SAW basic equation group and SAW mechanical boundary condition equation group are deduced from character equation of the crystal. Intrinsic SAW velocities are calculated using circle iterative method in three coordinate planes of quartz crystal systematically. Stiffness coefficient of piezoelectric crystal can be changed by piezoelectric effect and it is named as piezoelectric modified stiffness coefficient. Reciprocal velocity curves of quartz crystal in the three coordinate planes using the non-modified stiffness coefficients and the piezoelectric modified stiffness coefficients are drawn respectively. Configurations and periods of the curves are similar to projection figures of crystal lattice of the triangle crystal system in same coordinate planes. It means that there is internal relationship between the SAW properties and point group symmetries of the crystal. Research results lay a solid base for design and manufacture of the SAW device. It has theoretical significance and practical value.

  7. Fault diagnosis of reciprocating compressor valve with the method integrating acoustic emission signal and simulated valve motion

    NASA Astrophysics Data System (ADS)

    Wang, Yuefei; Xue, Chuang; Jia, Xiaohan; Peng, Xueyuan

    2015-05-01

    This paper proposes a method of diagnosing faults in reciprocating compressor valves using the acoustic emission signal coupled with the simulated valve motion. The actual working condition of a valve can be obtained by analyzing the acoustic emission signal in the crank angle domain and the valve movement can be predicted by simulating the valve motion. The exact opening and closing locations of a normal valve, provided by the simulated valve motion, can be used as references for the valve fault diagnosis. The typical valve faults are diagnosed to validate the feasibility and accuracy of the proposed method. The experimental results indicate that this method can easily distinguish the normal valve, valve flutter and valve delayed closing conditions. The characteristic locations of the opening and closing of the suction and discharge valves can be clearly identified in the waveform of the acoustic emission signal and the simulated valve motion.

  8. The surface variational principle applied to an acoustic cavity.

    PubMed

    Franco, F; Cunefare, K A

    2001-06-01

    This paper presents the development and application of the Surface Variational Principle (SVP) for the evaluation of axisymmetric interior acoustic domains. The interior form of the SVP is first developed in the same manner as the existing exterior form. Then, the surface pressure and normal velocity are represented with a Ritz expansion using basis functions that span the entire wetted surface of the object of interest. The resultant formulation is used to analyze the interior acoustic response of a harmonically forced, right circular elastic cylinder. This validation model was chosen as both the structural and acoustic responses can be solved analytically. Results are presented for two models: one with a length to radius ratio of 2.4, and another with a ratio of 12.3. The SVP is shown to well reproduce the analytical solution for this geometry, and displays the asymptotic convergence expected of its variational formulation. The SVP formulation developed here is not restricted to right-circular cylindrical geometries, and may, indeed, be readily applied to any axisymmetric body. PMID:11425122

  9. A reciprocal band-limited Green's function approach for modelling acoustic emission using the finite element method

    NASA Astrophysics Data System (ADS)

    Naber, R. R.; Bahai, H.; Jones, B. E.

    2006-05-01

    The ability to model acoustic emission (AE) plays an important role in advancing the reliability of AE source characterisation. In this paper, an efficient numerical approach is proposed for modelling AE waves in isotropic solids. The approach is based on evaluating the reciprocal band-limited Green's functions using the finite element (FE) method. In the first section, known analytical solutions of the Green's function for an elastic isotropic infinite plate subjected to point monopole surface loading are used to validate the approach. Then, a study investigating the effects of the spatial resolution of the FE model on the accuracy of the numerical solutions is presented. Furthermore, comparisons between numerical calculations and experimental measurements are presented for a glass plate subjected to two known AE sources (pencil lead break and ball impact). Finally, the reciprocal relation between the source and the receiver is confirmed using numerical simulations of a plane stress model of an elastic isotropic plate.

  10. Adjoint problem in duct acoustics and its reciprocity to forward problem by the Time Domain Wave Packet method

    NASA Astrophysics Data System (ADS)

    Kocaogul, Ibrahim; Hu, Fang; Li, Xiaodong

    2014-03-01

    Radiation of acoustic waves at all frequencies can be obtained by Time Domain Wave Packet (TDWP) method in a single time domain computation. Other benefit of the TDWP method is that it makes possible the separation of acoustic and instability wave in the shear flow. The TDWP method is also particularly useful for computations in the ducted or waveguide environments where incident wave modes can be imposed cleanly without a potentially long transient period. The adjoint equations for the linearized Euler equations are formulated for the Cartesian coordinates. Analytical solution for adjoint equations is derived by using Green's function in 2D and 3D. The derivation of reciprocal relations is presented for closed and open ducts. The adjoint equations are then solved numerically in reversed time by the TDWP method. Reciprocal relation between the duct mode amplitudes and far field point sources in the presence of the exhaust shear flow is computed and confirmed numerically. Applications of the adjoint problem to closed and open ducts are also presented.

  11. Fault Detection of Reciprocating Compressors using a Model from Principles Component Analysis of Vibrations

    NASA Astrophysics Data System (ADS)

    Ahmed, M.; Gu, F.; Ball, A. D.

    2012-05-01

    Traditional vibration monitoring techniques have found it difficult to determine a set of effective diagnostic features due to the high complexity of the vibration signals originating from the many different impact sources and wide ranges of practical operating conditions. In this paper Principal Component Analysis (PCA) is used for selecting vibration feature and detecting different faults in a reciprocating compressor. Vibration datasets were collected from the compressor under baseline condition and five common faults: valve leakage, inter-cooler leakage, suction valve leakage, loose drive belt combined with intercooler leakage and belt loose drive belt combined with suction valve leakage. A model using five PCs has been developed using the baseline data sets and the presence of faults can be detected by comparing the T2 and Q values from the features of fault vibration signals with corresponding thresholds developed from baseline data. However, the Q -statistic procedure produces a better detection as it can separate the five faults completely.

  12. The entropy of the noncommutative acoustic black hole based on generalized uncertainty principle

    NASA Astrophysics Data System (ADS)

    Anacleto, M. A.; Brito, F. A.; Passos, E.; Santos, W. P.

    2014-10-01

    In this paper we investigate statistical entropy of a 3-dimensional rotating acoustic black hole based on generalized uncertainty principle. In our results we obtain an area entropy and a correction term associated with the noncommutative acoustic black hole when λ introduced in the generalized uncertainty principle takes a specific value. However, in this method, it is not needed to introduce the ultraviolet cut-off and divergences are eliminated. Moreover, the small mass approximation is not necessary in the original brick-wall model.

  13. Computational principles underlying the recognition of acoustic signals in insects.

    PubMed

    Clemens, Jan; Hennig, R Matthias

    2013-08-01

    Many animals produce pulse-like signals during acoustic communication. These signals exhibit structure on two time scales: they consist of trains of pulses that are often broadcast in packets-so called chirps. Temporal parameters of the pulse and of the chirp are decisive for female preference. Despite these signals being produced by animals from many different taxa (e.g. frogs, grasshoppers, crickets, bushcrickets, flies), a general framework for their evaluation is still lacking. We propose such a framework, based on a simple and physiologically plausible model. The model consists of feature detectors, whose time-varying output is averaged over the signal and then linearly combined to yield the behavioral preference. We fitted this model to large data sets collected in two species of crickets and found that Gabor filters--known from visual and auditory physiology--explain the preference functions in these two species very well. We further explored the properties of Gabor filters and found a systematic relationship between parameters of the filters and the shape of preference functions. Although these Gabor filters were relatively short, they were also able to explain aspects of the preference for signal parameters on the longer time scale due to the integration step in our model. Our framework explains a wide range of phenomena associated with female preference for a widespread class of signals in an intuitive and physiologically plausible fashion. This approach thus constitutes a valuable tool to understand the functioning and evolution of communication systems in many species. PMID:23417450

  14. Reciprocity principle-based model for shielding effectiveness prediction of a rectangular cavity with a covered aperture

    NASA Astrophysics Data System (ADS)

    Jiao, Chong-Qing; Li, Yue-Yue

    2015-10-01

    According to the reciprocity principle, we propose an efficient model to compute the shielding effectiveness of a rectangular cavity with apertures covered by conductive sheet against an external incident electromagnetic wave. This problem is converted into another problem of solving the electromagnetic field leakage from the cavity when the cavity is excited by an electric dipole placed within it. By the combination of the unperturbed cavity field and the transfer impedance of the sheet, the tangential electric field distribution on the outer surface of the sheet is obtained. Then, the field distribution is regarded as an equivalent surface magnetic current source responsible for the leakage field. The validation of this model is verified by a comparison with the circuital model and the full-wave simulations. This time-saving model can deal with arbitrary aperture shape, various wave propagation and polarization directions, and the near-field effect. Project supported by the National Natural Science Foundation of China (Grant No. 51307055) and in part by the State Grid Corporation of China (Grant No. No. SGRI-WD-71-12-009).

  15. Acoustical analysis and modeling of reciprocating compressors, noise produced by gas pulsation, using four-pole method. I

    NASA Astrophysics Data System (ADS)

    Herfat, Ali T.; Seel, Robert V.

    2003-04-01

    Presented in Paper I are the fluid-structure interactions, structural dynamics, and thermodynamic analyses of reciprocating compressors (such as air conditioning and refrigeration reciprocating compressors). The compressor performance can be analyzed using the follows criteria: (1) thermodynamic model of the cylinder process, using the polytropic process model for thermodynamic model of cylinder; (2) suction and discharge valves dynamics analysis and modeling; (3) the valves modeling and the cylinder volume calculation; (4) Effective flow area and effective force area models.

  16. Hierarchical Classification by Multi-Level Reciprocity

    ERIC Educational Resources Information Center

    McQuitty, Louis L.

    1970-01-01

    A method is developed and illustrated which relaxes the principle of reciprocity in relation to characteristics of data and classifies in terms of successive levels of reciprocity, using two versions: (a) successive linkages, and (b) core assignments. (Author/RF)

  17. First-principles approach to the dynamic magnetoelectric couplings for the non-reciprocal directional dichroism in BiFeO3

    DOE PAGESBeta

    Kezsmarki, I.; Fishman, Randy Scott

    2016-04-18

    Due to the complicated magnetic and crystallographic structures of BiFeO3, its magnetoelectric (ME) couplings and microscopic model Hamiltonian remain poorly understood. By employing a firstprinciples approach, we uncover all possibleMEcouplings associated with the spin-current (SC) and exchange-striction (ES) polarizations, and construct an appropriate Hamiltonian for the long-range spin-cycloid in BiFeO3. First-principles calculations are used to understand the microscopic origins of theMEcouplings.Wefind that inversion symmetries broken by ferroelectric and antiferroelectric distortions induce the SC and the ES polarizations, which cooperatively produce the dynamicME effects in BiFeO3. A model motivated by first principles reproduces the absorption difference of counter-propagating light beams calledmore » non-reciprocal directional dichroism. The current paper focuses on the spin-driven (SD) polarizations produced by a dynamic electric field, i.e. the dynamic MEcouplings. Due to the inertial properties of Fe, the dynamic SD polarizations differ significantly from the static SD polarizations. Our systematic approach can be generally applied to any multiferroic material, laying the foundation for revealing hiddenMEcouplings on the atomic scale and for exploiting opticalMEeffects in the next generation of technological devices such as optical diodes.« less

  18. First-principles approach to the dynamic magnetoelectric couplings for the non-reciprocal directional dichroism in BiFeO3

    NASA Astrophysics Data System (ADS)

    Lee, Jun Hee; Kézsmáki, István; Fishman, Randy S.

    2016-04-01

    Due to the complicated magnetic and crystallographic structures of BiFeO3, its magnetoelectric (ME) couplings and microscopic model Hamiltonian remain poorly understood. By employing a first-principles approach, we uncover all possible ME couplings associated with the spin-current (SC) and exchange-striction (ES) polarizations, and construct an appropriate Hamiltonian for the long-range spin-cycloid in BiFeO3. First-principles calculations are used to understand the microscopic origins of the ME couplings. We find that inversion symmetries broken by ferroelectric and antiferroelectric distortions induce the SC and the ES polarizations, which cooperatively produce the dynamic ME effects in BiFeO3. A model motivated by first principles reproduces the absorption difference of counter-propagating light beams called non-reciprocal directional dichroism. The current paper focuses on the spin-driven (SD) polarizations produced by a dynamic electric field, i.e. the dynamic ME couplings. Due to the inertial properties of Fe, the dynamic SD polarizations differ significantly from the static SD polarizations. Our systematic approach can be generally applied to any multiferroic material, laying the foundation for revealing hidden ME couplings on the atomic scale and for exploiting optical ME effects in the next generation of technological devices such as optical diodes. This manuscript has been written by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan.

  19. Acoustics

    NASA Astrophysics Data System (ADS)

    The acoustics research activities of the DLR fluid-mechanics department (Forschungsbereich Stroemungsmechanik) during 1988 are surveyed and illustrated with extensive diagrams, drawings, graphs, and photographs. Particular attention is given to studies of helicopter rotor noise (high-speed impulsive noise, blade/vortex interaction noise, and main/tail-rotor interaction noise), propeller noise (temperature, angle-of-attack, and nonuniform-flow effects), noise certification, and industrial acoustics (road-vehicle flow noise and airport noise-control installations).

  20. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

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

  1. Electromagnetic Reciprocity.

    SciTech Connect

    Aldridge, David F.

    2014-11-01

    A reciprocity theorem is an explicit mathematical relationship between two different wavefields that can exist within the same space - time configuration. Reciprocity theorems provi de the theoretical underpinning for mod ern full waveform inversion solutions, and also suggest practical strategies for speed ing up large - scale numerical modeling of geophysical datasets . In the present work, several previously - developed electromagnetic r eciprocity theorems are generalized to accommodate a broader range of medi um, source , and receiver types. Reciprocity relations enabling the interchange of various types of point sources and point receivers within a three - dimensional electromagnetic model are derived. Two numerical modeling algorithms in current use are successfully tested for adherence to reciprocity. Finally, the reciprocity theorem forms the point of departure for a lengthy derivation of electromagnetic Frechet derivatives. These mathe matical objects quantify the sensitivity of geophysical electromagnetic data to variatio ns in medium parameters, and thus constitute indispensable tools for solution of the full waveform inverse problem. ACKNOWLEDGEMENTS Sandia National Labor atories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000. Signif icant portions of the work reported herein were conducted under a Cooperative Research and Development Agreement (CRADA) between Sandia National Laboratories (SNL) and CARBO Ceramics Incorporated. The author acknowledges Mr. Chad Cannan and Mr. Terry Pa lisch of CARBO Ceramics, and Ms. Amy Halloran, manager of SNL's Geophysics and Atmospheric Sciences Department, for their interest in and encouragement of this work. Special thanks are due to Dr . Lewis C. Bartel ( recently retired from Sandia National Labo ratories and now a

  2. Laboratory {open_quotes}proof of principle{close_quotes} investigation for the acoustically enhanced remediation technology

    SciTech Connect

    Iovenitti, J.L.; Spencer, J.W. Jr.; Hill, D.G.

    1995-10-01

    Weiss Associates is conducting a three phase program investigating the systematics of using acoustic excitation fields (AEFs) to enhance the in-situ remediation of contaminated soil and ground water under both saturated and unsaturated conditions: Phase I - Laboratory Scale Parametric Investigation; Phase II - Technology Scaling Study; and Phase III - Large Scale Field Tests. Phase I, the subject of this paper, consisted primarily of a laboratory proof of principle investigation. The field deployment and engineering viability of acoustically enhanced remediation (AER) technology was also examined. Phase II is a technology scaling study addressing the scale up between laboratory size samples on the order of inches, and the data required for field scale testing, on the order of hundreds of feet. Phase III will consist of field scale testing at an non-industrialized, non-contaminated site and at a contaminated site to validate the technology. Summarized herein are the results of the Phase I {open_quotes}proof-of-principle{close_quotes} investigation, and recommendations for Phase H. A general overview of AER technology along with the plan for the Phase I investigation was presented.

  3. Reciprocal translocations

    SciTech Connect

    1993-12-31

    Chapter 26, describes reciprocal translocations of chromosomes: their occurrence, breakpoints, and multiple rearrangements. In addition, phenotypes of balanced and unbalanced translocation carriers and fetal death are discussed. Examples of translocation families are given. Meiosis and genetic risk in translocation carriers is presented. Finally, sperm chromosomes in meiotic segregation analysis is mentioned. 39 refs., 3 figs., 1 tab.

  4. Derivation of a Ritz series modeling technique for acoustic cavity-structural systems based on a constrained Hamilton's principle.

    PubMed

    Ginsberg, Jerry H

    2010-05-01

    Hamilton's principle for dynamic systems is adapted to describe the coupled response of a confined acoustic domain and an elastic structure that forms part or all of the boundary. A key part of the modified principle is the treatment of the surface traction as a Lagrange multiplier function that enforces continuity conditions at the fluid-solid interface. The structural displacement, fluid velocity potential, and traction are represented by Ritz series, where the usage of the velocity potential as the state variable for the fluid assures that the flow is irrotational. Designation of the coefficients of the potential function series as generalized velocities leads to corresponding series representations of the particle velocity, displacement, and pressure in the fluid, which in turn leads to descriptions of the mechanical energies and virtual work. Application of the calculus of variations to Hamilton's principle yields linear differential-algebraic equations whose form is identical to those governing mechanical systems that are subject to nonholonomic kinematic constraints. Criteria for selection of basis functions for the various Ritz series are illustrated with an example of a rectangular cavity bounded on one side by an elastic plate and conditions that change discontinuously on other sides. PMID:21117723

  5. An Introduction to the Onsager Reciprocal Relations

    ERIC Educational Resources Information Center

    Monroe, Charles W.; Newman, John

    2007-01-01

    The Onsager reciprocal relations are essential to multicomponent transport theory. A discussion of the principles that should be used to derive flux laws for coupled diffusion is presented here. Fluctuation theory is employed to determine the reciprocal relation for transport coefficients that characterize coupled mass and heat transfer in binary…

  6. Education, Gift and Reciprocity: A Preliminary Discussion

    ERIC Educational Resources Information Center

    Sabourin, Eric

    2013-01-01

    This paper analyzes the importance and role of the reciprocity relationship in education. It presents a review on the mobilization of the principle of reciprocity--in the anthropological but also sociological and economic senses--in educational processes, especially in adult education. The study is divided into three parts. The first part analyzes…

  7. Near-field acoustic holography using sparse regularization and compressive sampling principles.

    PubMed

    Chardon, Gilles; Daudet, Laurent; Peillot, Antoine; Ollivier, François; Bertin, Nancy; Gribonval, Rémi

    2012-09-01

    Regularization of the inverse problem is a complex issue when using near-field acoustic holography (NAH) techniques to identify the vibrating sources. This paper shows that, for convex homogeneous plates with arbitrary boundary conditions, alternative regularization schemes can be developed based on the sparsity of the normal velocity of the plate in a well-designed basis, i.e., the possibility to approximate it as a weighted sum of few elementary basis functions. In particular, these techniques can handle discontinuities of the velocity field at the boundaries, which can be problematic with standard techniques. This comes at the cost of a higher computational complexity to solve the associated optimization problem, though it remains easily tractable with out-of-the-box software. Furthermore, this sparsity framework allows us to take advantage of the concept of compressive sampling; under some conditions on the sampling process (here, the design of a random array, which can be numerically and experimentally validated), it is possible to reconstruct the sparse signals with significantly less measurements (i.e., microphones) than classically required. After introducing the different concepts, this paper presents numerical and experimental results of NAH with two plate geometries, and compares the advantages and limitations of these sparsity-based techniques over standard Tikhonov regularization. PMID:22978881

  8. Control of coherent backscattering by breaking optical reciprocity

    NASA Astrophysics Data System (ADS)

    Bromberg, Y.; Redding, B.; Popoff, S. M.; Cao, H.

    2016-02-01

    Reciprocity is a universal principle that has a profound impact on many areas of physics. A fundamental phenomenon in condensed-matter physics, optical physics, and acoustics, arising from reciprocity, is the constructive interference of quantum or classical waves which propagate along time-reversed paths in disordered media, leading to, for example, weak localization and metal-insulator transition. Previous studies have shown that such coherent effects are suppressed when reciprocity is broken. Here we experimentally show that by tuning a nonreciprocal phase we can coherently control complex coherent phenomena, rather than simply suppress them. In particular, we manipulate coherent backscattering of light, also known as weak localization. By utilizing a magneto-optical effect, we control the interference between time-reversed paths inside a multimode fiber with strong mode mixing, observe the optical analog of weak antilocalization, and realize a continuous transition from weak localization to weak antilocalization. Our results may open new possibilities for coherent control of waves in complex systems.

  9. Musical Acoustics

    NASA Astrophysics Data System (ADS)

    Gough, Colin

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

  10. From Born Reciprocity to Reciprocal Relativity: A Paradigm for Space-Time Physics

    NASA Astrophysics Data System (ADS)

    Jarvis, Peter

    Born's principle of reciprocity -- the exchangeability of relativistic energy-momentum and time-position -- can be seen as a discrete element of a continuous group of symmetry transformations which transcend relativity. Invariance under the semi-direct product of the Weyl-Heisenberg group H(4) of canonical commutation relations with the non-compact unitary group U(3, 1) -- the so-called quaplectic group U(3, 1) ⋉ H(4) -- has been considered by Low as an extension of Born reciprocity to a fundamental symmetry principle of `reciprocal relativity' for the physics of non-inertial frames and high energy processes...

  11. Reciprocity and Ethical Tuberculosis Treatment and Control.

    PubMed

    Silva, Diego S; Dawson, Angus; Upshur, Ross E G

    2016-03-01

    This paper explores the notion of reciprocity in the context of active pulmonary and laryngeal tuberculosis (TB) treatment and related control policies and practices. We seek to do three things: First, we sketch the background to contemporary global TB care and suggest that poverty is a key feature when considering the treatment of TB patients. We use two examples from TB care to explore the role of reciprocity: isolation and the use of novel TB drugs. Second, we explore alternative means of justifying the use of reciprocity through appeal to different moral and political theoretical traditions (i.e., virtue ethics, deontology, and consequentialism). We suggest that each theory can be used to provide reasons to take reciprocity seriously as an independent moral concept, despite any other differences. Third, we explore general meanings and uses of the concept of reciprocity, with the primary intention of demonstrating that it cannot be simply reduced to other more frequently invoked moral concepts such as beneficence or justice. We argue that reciprocity can function as a mid-level principle in public health, and generally, captures a core social obligation arising once an individual or group is burdened as a result of acting for the benefit of others (even if they derive a benefit themselves). We conclude that while more needs to be explored in relation to the theoretical justification and application of reciprocity, sufficient arguments can be made for it to be taken more seriously as a key principle within public health ethics and bioethics more generally. PMID:26797512

  12. β-reciprocal polynomials

    NASA Astrophysics Data System (ADS)

    Withers, Christopher S.; Nadarajah, Saralees

    2016-07-01

    A new class of polynomials pn(x) known as β-reciprocal polynomials is defined. Given a parameter ? that is not a root of -1, we show that the only β-reciprocal polynomials are pn(x) ≡ xn. When β is a root of -1, other polynomials are possible. For example, the Hermite polynomials are i-reciprocal, ?.

  13. Reciprocating pellet press

    DOEpatents

    Jones, Charles W.

    1981-04-07

    A machine for pressing loose powder into pellets using a series of reciprocating motions has an interchangeable punch and die as its only accurately machines parts. The machine reciprocates horizontally between powder receiving and pressing positions. It reciprocates vertically to press, strip and release a pellet.

  14. [The experience in employing reciprocal gait orthoses].

    PubMed

    Radło, W; Miklaszewski, K; Gasińska, M; Michno, P

    1999-01-01

    The paper presents the experience of the authors in employing reciprocal gait orthoses in a group of 23 patients age 3-25 years (mean age 7.8 years). The orthoses were indicated in patients with flaccid paresis (17 children with myelodysplasia and 3 patients with traumatic paraplegia) and with arthrogryposis (3 patients). The follow-up period was 6 months to 5 years (mean 2.4 years). The authors discuss the principles of construction and operation of reciprocal gait orthoses and types of patients in whom they are recommended. The principles of learning walking and using the orthosis are also presented. PMID:10367535

  15. Thermodynamic Constraints on Reflectance Reciprocity and Kirchhoff's Law.

    PubMed

    Snyder, W C; Wan, Z; Li, X

    1998-06-01

    Contrary to common belief, neither reciprocity of the bidirectional reflectance distribution function (BRDF) nor the directional form of Kirchhoff's electromagnetic radiation law can be demonstrated on the basis of energy conservation. The BRDF is generally considered reciprocal as an extension of Helmholtz reciprocity, but Helmholtz reciprocity does not always hold. We describe the flaw in a thermodynamic demonstration of reciprocity that uses an enclosure calculation. Some conclusions can be drawn from the enclosure calculation, but reciprocity requires more restrictive conditions. We conclude that, although they can be violated, reciprocity and the directional form of Kirchhoff's law generally hold because of the quantum-mechanical principle of time-reversal invariance, which applies to most materials. PMID:18273310

  16. An Autonomously Reciprocating Transmembrane Nanoactuator.

    PubMed

    Watson, Matthew A; Cockroft, Scott L

    2016-01-22

    Biological molecular machines operate far from equilibrium by coupling chemical potential to repeated cycles of dissipative nanomechanical motion. This principle has been exploited in supramolecular systems that exhibit true machine behavior in solution and on surfaces. However, designed membrane-spanning assemblies developed to date have been limited to simple switches or stochastic shuttles, and true machine behavior has remained elusive. Herein, we present a transmembrane nanoactuator that turns over chemical fuel to drive autonomous reciprocating (back-and-forth) nanomechanical motion. Ratcheted reciprocating motion of a DNA/PEG copolymer threaded through a single α-hemolysin pore was induced by a combination of DNA strand displacement processes and enzyme-catalyzed reactions. Ion-current recordings revealed saw-tooth patterns, indicating that the assemblies operated in autonomous, asymmetric cycles of conformational change at rates of up to one cycle per minute. PMID:26661295

  17. Electromechanical acoustic liner

    NASA Technical Reports Server (NTRS)

    Sheplak, Mark (Inventor); Cattafesta, III, Louis N. (Inventor); Nishida, Toshikazu (Inventor); Horowitz, Stephen Brian (Inventor)

    2007-01-01

    A multi-resonator-based system responsive to acoustic waves includes at least two resonators, each including a bottom plate, side walls secured to the bottom plate, and a top plate disposed on top of the side walls. The top plate includes an orifice so that a portion of an incident acoustical wave compresses gas in the resonators. The bottom plate or the side walls include at least one compliant portion. A reciprocal electromechanical transducer coupled to the compliant portion of each of the resonators forms a first and second transducer/compliant composite. An electrical network is disposed between the reciprocal electromechanical transducer of the first and second resonator.

  18. 26 CFR 521.116 - Reciprocal administrative assistance.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 19 2011-04-01 2010-04-01 true Reciprocal administrative assistance. 521.116... of Denmark and of Danish Corporations § 521.116 Reciprocal administrative assistance. (a) General. (1) By Article XVII of the convention, the United States and Denmark adopt the principle of exchange...

  19. Reciprocity in directed networks

    NASA Astrophysics Data System (ADS)

    Yin, Mei; Zhu, Lingjiong

    2016-04-01

    Reciprocity is an important characteristic of directed networks and has been widely used in the modeling of World Wide Web, email, social, and other complex networks. In this paper, we take a statistical physics point of view and study the limiting entropy and free energy densities from the microcanonical ensemble, the canonical ensemble, and the grand canonical ensemble whose sufficient statistics are given by edge and reciprocal densities. The sparse case is also studied for the grand canonical ensemble. Extensions to more general reciprocal models including reciprocal triangle and star densities will likewise be discussed.

  20. Reciprocity-Based Reasons for Benefiting Research Participants: Most Fail, the Most Plausible is Problematic

    PubMed Central

    Sofaer, Neema

    2014-01-01

    A common reason for giving research participants post-trial access (PTA) to the trial intervention appeals to reciprocity, the principle, stated most generally, that if one person benefits a second, the second should reciprocate: benefit the first in return. Many authors consider it obvious that reciprocity supports PTA. Yet their reciprocity principles differ, with many authors apparently unaware of alternative versions. This article is the first to gather the range of reciprocity principles. It finds that: (1) most are false. (2) The most plausible principle, which is also problematic, applies only when participants experience significant net risks or burdens. (3) Seldom does reciprocity support PTA for participants or give researchers stronger reason to benefit participants than equally needy non-participants. (4) Reciprocity fails to explain the common view that it is bad when participants in a successful trial have benefited from the trial intervention but lack PTA to it. PMID:24602060

  1. Reciprocal Rights and Responsibilities in Parent-Child Relations

    ERIC Educational Resources Information Center

    Baumrind, Diana

    1978-01-01

    This article examines critically the case for protecting children's rights as against the case for protecting children's welfare. The principle of reciprocity in parent-child relations is rejected. (Author/AM)

  2. Reciprocal NUT spacetimes

    NASA Astrophysics Data System (ADS)

    Momeni, Davood; Chattopadhyay, Surajit; Myrzakulov, Ratbay

    2015-05-01

    In this paper, we study the Ehlers' transformation (sometimes called gravitational duality rotation) for reciprocal static metrics. First, we introduce the concept of reciprocal metric. We prove a theorem which shows how we can construct a certain new static solution of Einstein field equations using a seed metric. Later, we investigate the family of stationary spacetimes of such reciprocal metrics. The key here is a theorem from Ehlers', which relates any static vacuum solution to a unique stationary metric. The stationary metric has a magnetic charge. The spacetime represents Newman-Unti-Tamburino (NUT) solutions. Since any stationary spacetime can be decomposed into a 1 + 3 time-space decomposition, Einstein field equations for any stationary spacetime can be written in the form of Maxwell's equations for gravitoelectromagnetic fields. Further, we show that this set of equations is invariant under reciprocal transformations. An additional point is that the NUT charge changes the sign. As an instructive example, by starting from the reciprocal Schwarzschild as a spherically symmetric solution and reciprocal Morgan-Morgan disk model as seed metrics we find their corresponding stationary spacetimes. Starting from any static seed metric, performing the reciprocal transformation and by applying an additional Ehlers' transformation we obtain a family of NUT spaces with negative NUT factor (reciprocal NUT factors).

  3. Reciprocating Linear Electric Motor

    NASA Technical Reports Server (NTRS)

    Goldowsky, M. P.

    1984-01-01

    Features include structural simplicity and good force/displacement characteristics. Reciprocating motor has simple, rugged construction, relatively low reciprocating weight, improved power delivery, and improved force control. Wear reduced by use of magnetic bearings. Intended to provide drivers for long-lived Stirling-cycle cryogenic refrigerators, concept has less exotic applications, such as fuel pumps.

  4. The Value of Reciprocity

    ERIC Educational Resources Information Center

    Molm, Linda D.; Schaefer, David R.; Collett, Jessica L.

    2007-01-01

    The value of reciprocity in social exchange potentially comprises both instrumental value (the value of the actual benefits received from exchange) and communicative or symbolic value (the expressive and uncertainty reduction value conveyed by features of the act of reciprocity itself). While all forms of exchange provide instrumental value, we…

  5. The Structure of Reciprocity

    ERIC Educational Resources Information Center

    Molm, Linda D.

    2010-01-01

    Reciprocity is one of the defining features of social exchange and social life, yet exchange theorists have tended to take it for granted. Drawing on work from a decade-long theoretical research program, I argue that reciprocity is structured and variable across different forms of exchange, that these variations in the structure of reciprocity…

  6. Centrifugal reciprocating compressor

    NASA Technical Reports Server (NTRS)

    High, W. H.

    1980-01-01

    Efficient compressor uses centrifugal force to compress gas. System incorporates two coupled dc motors, each driving separate centrifugal reciprocating-compressor assembly. Motors are synchronized to accelerate and decelerate alternately.

  7. Hidden patterns of reciprocity.

    PubMed

    Syi

    2014-03-21

    Reciprocity can help the evolution of cooperation. To model both types of reciprocity, we need the concept of strategy. In the case of direct reciprocity there are four second-order action rules (Simple Tit-for-tat, Contrite Tit-for-tat, Pavlov, and Grim Trigger), which are able to promote cooperation. In the case of indirect reciprocity the key component of cooperation is the assessment rule. There are, again, four elementary second-order assessment rules (Image Scoring, Simple Standing, Stern Judging, and Shunning). The eight concepts can be formalized in an ontologically thin way we need only an action predicate and a value function, two agent concepts, and the constant of goodness. The formalism helps us to discover that the action and assessment rules can be paired, and that they show the same patterns. The logic of these patterns can be interpreted with the concept of punishment that has an inherent paradoxical nature. PMID:24368125

  8. Drift stabilizer for reciprocating free-piston devices

    DOEpatents

    Ward, William C.; Corey, John A.; Swift, Gregory W.

    2003-05-20

    A free-piston device has a stabilized piston drift. A piston having a frequency of reciprocation over a stroke length and with first and second sides facing first and second variable volumes, respectively, for containing a working fluid defining an acoustic wavelength at the frequency of reciprocation. A bypass tube waveguide connects the first and second variable volumes at all times during reciprocation of the piston. The waveguide has a relatively low impedance for steady flow and a relatively high impedance for oscillating flow at the frequency of reciprocation of the piston, so that steady flow returns fluid leakage from about the piston between the first and second volumes while oscillating flow is not diverted through the waveguide. Thus, net leakage about the piston is returned during each stroke of the piston while oscillating leakage is not allowed and pressure buildup on either the first or second side of the piston is avoided to provide a stable piston location.

  9. Primary calibration in acoustics metrology

    NASA Astrophysics Data System (ADS)

    Bacelar Milhomem, T. A.; Defilippo Soares, Z. M.

    2015-01-01

    SI unit in acoustics is realized by the reciprocity calibrations of laboratory standard microphones in pressure field, free field and diffuse field. Calibrations in pressure field and in free field are already consolidated and the Inmetro already done them. Calibration in diffuse field is not yet consolidated, however, some national metrology institutes, including Inmetro, are conducting researches on this subject. This paper presents the reciprocity calibration, the results of Inmetro in recent key comparisons and the research that is being developed for the implementation of reciprocity calibration in diffuse field.

  10. Direct reciprocity on graphs

    PubMed Central

    Ohtsuki, Hisashi; Nowak, Martin A.

    2008-01-01

    Direct reciprocity is a mechanism for the evolution of cooperation based on the idea of repeated encounters between the same two individuals. Here we examine direct reciprocity in structured populations, where individuals occupy the vertices of a graph. The edges denote who interacts with whom. The graph represents spatial structure or a social network. For birth-death or pairwise comparison updating, we find that evolutionary stability of direct reciprocity is more restrictive on a graph than in a well-mixed population, but the condition for reciprocators to be advantageous is less restrictive on a graph. For death-birth and imitation updating, in contrast, both conditions are easier to fulfill on a graph. Moreover, for all four update mechanisms, reciprocators can dominate defectors on a graph, which is never possible in a well-mixed population. We also study the effect of an error rate, which increases with the number of links per individual; interacting with more people simultaneously enhances the probability of making mistakes. We provide analytic derivations for all results. PMID:17466339

  11. Turbofan Acoustic Propagation and Radiation

    NASA Technical Reports Server (NTRS)

    Eversman, Walter

    2000-01-01

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

  12. Series of Reciprocal Triangular Numbers

    ERIC Educational Resources Information Center

    Bruckman, Paul; Dence, Joseph B.; Dence, Thomas P.; Young, Justin

    2013-01-01

    Reciprocal triangular numbers have appeared in series since the very first infinite series were summed. Here we attack a number of subseries of the reciprocal triangular numbers by methodically expressing them as integrals.

  13. Reciprocal Predicates in Japanese.

    ERIC Educational Resources Information Center

    Ishii, Yasuo

    A study of reciprocals in Japanese compares two kinds: (1) a verbal suffix "aw"; and (2) an NP argument "otagai." Although "otagai" appears to be taken care of by syntactic binding theory, it is proposed that there is no evidence for the existence of a syntactic position of the object NP in the case of "aw." The suffix can be characterized as…

  14. Terahertz wave reciprocal imaging

    NASA Astrophysics Data System (ADS)

    Xu, Jingzhou; Zhang, X.-C.

    2006-04-01

    A reciprocal imaging technology with an encoding/decoding image readout method allows a single detector (such as a heterodyne detector) to produce a two dimensional (2D) image simultaneously. Applying it in a pulsed terahertz imaging system could create a 2D terahertz image with 100pixels per frame which produces the same signal to noise ratio as a signal spot measurement.

  15. The design, characterization, and comparison of MEMS comb-drive acoustic emission transducers with the principles of area-change and gap-change

    NASA Astrophysics Data System (ADS)

    Kabir, Minoo; Saboonchi, Hossain; Ozevin, Didem

    2015-04-01

    Comb-drive transducers are made of interdigitized fingers formed by the stationary part known as stator and the moving part known as rotor, and based on the transduction principle of capacitance change. They can be designed as area-change or gap-change mechanism to convert the mechanical signal at in-plane direction into electrical output. The comb-drive transducers can be utilized to differentiate the wave motion in orthogonal directions when they are utilized with the outof- plane transducers. However, their sensitivity is weak to detect the wave motion released by newly formed damage surfaces. In this study, Micro-Electro-Mechanical System (MEMS) comb-drive Acoustic Emission (AE) transducer designs with two different mechanisms are designed, characterized and compared for sensing high frequency wave propagation. The MEMS AE transducers are manufactured using MetalMUMPs (Metal Multi-User MEMS Processes), which use electroplating technique for highly elevated microstructure geometries. Each type of the transducers is numerically modeled using COMSOL Multiphysics program in order to determine the sensitivity based on the applied load. The transducers are experimentally characterized and compared to the numerical models. The experiments include laser excitation to control the direction of the wave generation, and actual crack growth monitoring of aluminum 7075 specimens loaded under fatigue. Behavior and responses of the transducers are compared based on the parameters such as waveform signature, peak frequency, damping, sensitivity, and signal to noise ratio. The comparisons between the measured parameters are scaled according to the respective capacitance of each sensor in order to determine the most sensitive design geometry.

  16. Reciprocity relations in aerodynamics

    NASA Technical Reports Server (NTRS)

    Heaslet, Max A; Spreiter, John R

    1953-01-01

    Reverse flow theorems in aerodynamics are shown to be based on the same general concepts involved in many reciprocity theorems in the physical sciences. Reciprocal theorems for both steady and unsteady motion are found as a logical consequence of this approach. No restrictions on wing plan form or flight Mach number are made beyond those required in linearized compressible-flow analysis. A number of examples are listed, including general integral theorems for lifting, rolling, and pitching wings and for wings in nonuniform downwash fields. Correspondence is also established between the buildup of circulation with time of a wing starting impulsively from rest and the buildup of lift of the same wing moving in the reverse direction into a sharp-edged gust.

  17. Dynamic Reciprocity in the Wound Microenvironment

    PubMed Central

    Schultz, Gregory S.; Davidson, Jeffrey M.; Kirsner, Robert S.; Bornstein, Paul; Herman, Ira M.

    2011-01-01

    Here, we define dynamic reciprocity (DR) as an ongoing, bidirectional interaction amongst cells and their surrounding microenvironment. In the review, we posit that DR is especially meaningful during wound healing as the DR-driven biochemical, biophysical and cellular responses to injury play pivotal roles in regulating tissue regenerative responses. Such cell-extracellular matrix interactions not only guide and regulate cellular morphology, but cellular differentiation, migration, proliferation, and survival during tissue development, including e.g. embryogenesis, angiogenesis, as well as during pathologic processes including cancer diabetes, hypertension and chronic wound healing. Herein, we examine DR within the wound microenvironment while considering specific examples across acute and chronic wound healing. This review also considers how a number of hypotheses that attempt to explain chronic wound pathophysiology, which may be understood within the DR framework. The implications of applying the principles of dynamic reciprocity to optimize wound care practice and future development of innovative wound healing therapeutics are also briefly considered. PMID:21362080

  18. Acoustic neuroma

    MedlinePlus

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

  19. Broadband non-reciprocal transmission of sound with invariant frequency

    PubMed Central

    Gu, Zhong-ming; Hu, Jie; Liang, Bin; Zou, Xin-ye; Cheng, Jian-chun

    2016-01-01

    We design and experimentally demonstrate a broadband yet compact acoustic diode (AD) by using an acoustic nonlinear material and a pair of gain and lossy materials. Due to the capabilities of maintaining the original frequency and high forward transmission while blocking backscattered wave, our design is closer to the desired features of a perfect AD and is promising to play the essential diode-like role in realistic acoustic systems, such as ultrasound imaging, noise control and nondestructive testing. Furthermore, our design enables improving the sensitivity and the robustness of device simultaneously by tailoring an individual structural parameter. We envision our design will take a significant step towards the realization of applicable acoustic one-way devices, and inspire the research of non-reciprocal wave manipulation in other fields. PMID:26805712

  20. Broadband non-reciprocal transmission of sound with invariant frequency.

    PubMed

    Gu, Zhong-ming; Hu, Jie; Liang, Bin; Zou, Xin-ye; Cheng, Jian-chun

    2016-01-01

    We design and experimentally demonstrate a broadband yet compact acoustic diode (AD) by using an acoustic nonlinear material and a pair of gain and lossy materials. Due to the capabilities of maintaining the original frequency and high forward transmission while blocking backscattered wave, our design is closer to the desired features of a perfect AD and is promising to play the essential diode-like role in realistic acoustic systems, such as ultrasound imaging, noise control and nondestructive testing. Furthermore, our design enables improving the sensitivity and the robustness of device simultaneously by tailoring an individual structural parameter. We envision our design will take a significant step towards the realization of applicable acoustic one-way devices, and inspire the research of non-reciprocal wave manipulation in other fields. PMID:26805712

  1. Broadband non-reciprocal transmission of sound with invariant frequency

    NASA Astrophysics Data System (ADS)

    Gu, Zhong-Ming; Hu, Jie; Liang, Bin; Zou, Xin-Ye; Cheng, Jian-Chun

    2016-01-01

    We design and experimentally demonstrate a broadband yet compact acoustic diode (AD) by using an acoustic nonlinear material and a pair of gain and lossy materials. Due to the capabilities of maintaining the original frequency and high forward transmission while blocking backscattered wave, our design is closer to the desired features of a perfect AD and is promising to play the essential diode-like role in realistic acoustic systems, such as ultrasound imaging, noise control and nondestructive testing. Furthermore, our design enables improving the sensitivity and the robustness of device simultaneously by tailoring an individual structural parameter. We envision our design will take a significant step towards the realization of applicable acoustic one-way devices, and inspire the research of non-reciprocal wave manipulation in other fields.

  2. High pressure reciprocating pump

    SciTech Connect

    Besic, D.

    1990-05-01

    This patent describes an improvement in a reciprocating pump having a plunger and a pumping chamber. It comprises: the plunger having a bore communicating with an intersection opening and wherein the plunger incudes a central axis; a suction valve and a discharge valve, each having an axis of actuation parallel to a central axis of the plunger; the suction valve comprising a cylindrical core having a central passageway, and the core is slidably received by a seating member and resiliently biased to the seating member.

  3. Reciprocating magnetic refrigerator

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.

    1985-01-01

    A 4 to 15 K magnetic refrigerator to test as an alternative to the Joule-Thomson circuit as the low temperature stage of a 4 to 300 K closed-cycle refrigerator was developed. The reciprocating magnetic refrigerator consists of two matrices of gadolinium gallium garnet spheres located in tandem on a single piston which alternately moves each matrix into a 7 telsa magnetic field. A separate helium gas circuit is used as the heat exchange mechanism for the low and the high temperature extremes of the magnetic refrigerator. Details of the design and results of the initial refrigerator component tests are presented.

  4. Vertically reciprocating auger

    NASA Technical Reports Server (NTRS)

    Etheridge, Mark; Morgan, Scott; Fain, Robert; Pearson, Jonathan; Weldi, Kevin; Woodrough, Stephen B., Jr.

    1988-01-01

    The mathematical model and test results developed for the Vertically Reciprocating Auger (VRA) are summarized. The VRA is a device capable of transporting cuttings that result from below surface drilling. It was developed chiefly for the lunar surface, where conventional fluid flushing while drilling would not be practical. The VRA uses only reciprocating motion and transports material through reflections with the surface above. Particles are reflected forward and land ahead of radially placed fences, which prevent the particles from rolling back down the auger. Three input wave forms are considered to drive the auger. A modified sawtooth wave form was chosen for testing, over a modified square wave or sine wave, due to its simplicity and effectiveness. The three-dimensional mathematical model predicted a sand throughput rate of 0.2667 pounds/stroke, while the actual test setup transported 0.075 pounds/stroke. Based on this result, a correction factor of 0.281 is suggested for a modified sawtooth input.

  5. Reciprocal relations in electroacoustics

    SciTech Connect

    Chassagne, C.; Bedeaux, D.

    2014-07-28

    In a colloidal suspension, one can generate sound waves by the application of an alternating electric field (Electrokinetic Sonic Amplitude, i.e., ESA). Another phenomenon is electrophoresis (Electrophoretic Mobility, i.e., EM) where a colloidal particle moves relative to the solvent in an electric field. Vice versa one can generate electric fields or electric currents by sound waves (Colloid Vibration Potential/Current, i.e., CVP/CVI). In 1988 and 1990, O’Brien [J. Fluid Mech. 190, 71–86 (1988) and O’Brien, J. Fluid Mech. 212, 81–93 (1990)] derived a reciprocal relation between the proportionality coefficients of the EM and CVI phenomena. In this paper, we will generalize his proof by constructing the relevant entropy production from which the linear force-flux relations follow. General relations are derived for electrolyte solutions, of which colloidal suspensions are a particular case. The relations between CVI, CVP, EM, and ESA are discussed. O’Brien's reciprocal relation then follows as an Onsager relation. The relation is valid for any applied electric field frequency, particle surface charge and particle concentration (even in the presence of particle-particle interactions) provided the system is isotropic.

  6. Reciprocity Family Counseling: A Multi-Ethnic Model.

    ERIC Educational Resources Information Center

    Penrose, David M.

    The Reciprocity Family Counseling Method involves learning principles of behavior modification including selective reinforcement, behavioral contracting, self-correction, and over-correction. Selective reinforcement refers to the recognition and modification of parent/child responses and reinforcers. Parents and children are asked to identify…

  7. Toward a Behavior of Reciprocity

    PubMed Central

    Gernsbacher, Morton Ann

    2014-01-01

    It is frequently believed that autism is characterized by a lack of social or emotional reciprocity. In this article, I question that assumption by demonstrating how many professionals—researchers and clinicians—and likewise many parents, have neglected the true meaning of reciprocity. Reciprocity is “a relation of mutual dependence or action or influence,” or “a mode of exchange in which transactions take place between individuals who are symmetrically placed.” Assumptions by clinicians and researchers suggest that they have forgotten that reciprocity needs to be mutual and symmetrical—that reciprocity is a two-way street. Research is reviewed to illustrate that when professionals, peers, and parents are taught to act reciprocally, autistic children become more responsive. In one randomized clinical trial of “reciprocity training” to parents, their autistic children's language developed rapidly and their social engagement increased markedly. Other demonstrations of how parents and professionals can increase their behavior of reciprocity are provided. PMID:25598865

  8. Indirect reciprocity in three types of social dilemmas.

    PubMed

    Nakamura, Mitsuhiro; Ohtsuki, Hisashi

    2014-08-21

    Indirect reciprocity is a key mechanism for the evolution of human cooperation. Previous studies explored indirect reciprocity in the so-called donation game, a special class of Prisoner's Dilemma (PD) with unilateral decision making. A more general class of social dilemmas includes Snowdrift (SG), Stag Hunt (SH), and PD games, where two players perform actions simultaneously. In these simultaneous-move games, moral assessments need to be more complex; for example, how should we evaluate defection against an ill-reputed, but now cooperative, player? We examined indirect reciprocity in the three social dilemmas and identified twelve successful social norms for moral assessments. These successful norms have different principles in different dilemmas for suppressing cheaters. To suppress defectors, any defection against good players is prohibited in SG and PD, whereas defection against good players may be allowed in SH. To suppress unconditional cooperators, who help anyone and thereby indirectly contribute to jeopardizing indirect reciprocity, we found two mechanisms: indiscrimination between actions toward bad players (feasible in SG and PD) or punishment for cooperation with bad players (effective in any social dilemma). Moreover, we discovered that social norms that unfairly favor reciprocators enhance robustness of cooperation in SH, whereby reciprocators never lose their good reputation. PMID:24721479

  9. Trust, Respect, and Reciprocity

    PubMed Central

    Phong, Tran Viet; Nhan, Le Nguyen Thanh; Dung, Nguyen Thanh; Ngan, Ta Thi Dieu; Kinh, Nguyen Van; Parker, Michael; Bull, Susan

    2015-01-01

    International science funders and publishers are driving a growing trend in data sharing. There is mounting pressure on researchers in low- and middle-income settings to conform to new sharing policies, despite minimal empirically grounded accounts of the ethical challenges of implementing the policies in these settings. This study used in-depth interviews and focus group discussions with 48 stakeholders in Vietnam to explore the experiences, attitudes, and expectations that inform ethical and effective approaches to sharing clinical research data. Distinct views on the role of trust, respect, and reciprocity were among those that emerged to inform culturally appropriate best practices. We conclude by discussing the challenges that authors of data-sharing policies should consider in this unique context. PMID:26297747

  10. Reciprocating linear motor

    NASA Technical Reports Server (NTRS)

    Goldowsky, Michael P. (Inventor)

    1987-01-01

    A reciprocating linear motor is formed with a pair of ring-shaped permanent magnets having opposite radial polarizations, held axially apart by a nonmagnetic yoke, which serves as an axially displaceable armature assembly. A pair of annularly wound coils having axial lengths which differ from the axial lengths of the permanent magnets are serially coupled together in mutual opposition and positioned with an outer cylindrical core in axial symmetry about the armature assembly. One embodiment includes a second pair of annularly wound coils serially coupled together in mutual opposition and an inner cylindrical core positioned in axial symmetry inside the armature radially opposite to the first pair of coils. Application of a potential difference across a serial connection of the two pairs of coils creates a current flow perpendicular to the magnetic field created by the armature magnets, thereby causing limited linear displacement of the magnets relative to the coils.

  11. Reciprocating wind engine

    SciTech Connect

    Van Mechelen, B.

    1980-12-09

    A reciprocating wind engine is described which utilizes plural, movably mounted sets of panels to form pistons. Cooperating first and second pistons may be spaced from each other on either side of a central crankshaft. As the wind strikes the surface of a first set of panels, the first piston is moved toward the crankshaft and the second piston is pulled toward the crankshaft from the opposite side. When both pistons are adjacent the crankshaft, the panels on the first or windward piston open to allow the wind to pass therethrough into contact with the panels of the second piston which are closed to present a uniform surface to the wind. The pistons are forced away from the crankshaft to complete one cycle of operation. The output from the crankshaft may be utilized to generate electricity, or for any other suitable purpose. Plural engine segments may be cooperatively joined together to form a bank of such units.

  12. Performance Comparison of Capacity Control Methods for Reciprocating Compressors

    NASA Astrophysics Data System (ADS)

    Wang, L.; Liu, G. B.; Zhao, Y. Y.; Li, L. L.

    2015-08-01

    Different capacity control methods are used for adjusting suction flow of reciprocating compressors to meet process need. Compared with recycle or bypass and suction throttling, three capacity control methods of speed control, clearance pockets and suction valve unloading are preferred due to their energy-saving at operating condition of partial load. The paper reviewed state of the art of the current capacity control technologies and their principles. A comprehensive mathematical model was developed to predict thermodynamic and dynamic performance of reciprocating compressors equipped with the capacity control systems of four above-mentioned methods. Comparison of shaft work and mechanical efficiency were conducted for different capacity control methods at the same condition. In addition, their influence on p-v diagram and valve motion were also studied, which is important for reliability and life of the reciprocating compressors. These results were helpful for selection of the capacity control systems by end-users and optimum design by manufacturers.

  13. Simpler valve for reciprocating engines

    NASA Technical Reports Server (NTRS)

    Akkerman, J. W.

    1978-01-01

    Simpler design eliminating camshafts, cams, and mechanical springs should improve reliability of hydrazine powered reciprocating engines. Valve is expected to improve efficiency, and reduce weight of engines in range up to 50 horsepower.

  14. Moral assessment in indirect reciprocity

    PubMed Central

    Sigmund, Karl

    2012-01-01

    Indirect reciprocity is one of the mechanisms for cooperation, and seems to be of particular interest for the evolution of human societies. A large part is based on assessing reputations and acting accordingly. This paper gives a brief overview of different assessment rules for indirect reciprocity, and studies them by using evolutionary game dynamics. Even the simplest binary assessment rules lead to complex outcomes and require considerable cognitive abilities. PMID:21473870

  15. Group formation through indirect reciprocity

    NASA Astrophysics Data System (ADS)

    Oishi, Koji; Shimada, Takashi; Ito, Nobuyasu

    2013-03-01

    The emergence of group structure of cooperative relations is studied in an agent-based model. It is proved that specific types of reciprocity norms lead individuals to split into two groups only inside of which they are cooperative. The condition for the evolutionary stability of the norms is also obtained. This result suggests reciprocity norms, which usually promote cooperation, can cause society's separation into multiple groups.

  16. Indirect Reciprocity; A Field Experiment

    PubMed Central

    van Apeldoorn, Jacobien; Schram, Arthur

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties) in the past. This provides clear evidence of (downstream) indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties), however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one’s trustworthiness as a service user. PMID:27043712

  17. Direct reciprocity in structured populations

    PubMed Central

    van Veelen, Matthijs; García, Julián; Rand, David G.; Nowak, Martin A.

    2012-01-01

    Reciprocity and repeated games have been at the center of attention when studying the evolution of human cooperation. Direct reciprocity is considered to be a powerful mechanism for the evolution of cooperation, and it is generally assumed that it can lead to high levels of cooperation. Here we explore an open-ended, infinite strategy space, where every strategy that can be encoded by a finite state automaton is a possible mutant. Surprisingly, we find that direct reciprocity alone does not lead to high levels of cooperation. Instead we observe perpetual oscillations between cooperation and defection, with defection being substantially more frequent than cooperation. The reason for this is that “indirect invasions” remove equilibrium strategies: every strategy has neutral mutants, which in turn can be invaded by other strategies. However, reciprocity is not the only way to promote cooperation. Another mechanism for the evolution of cooperation, which has received as much attention, is assortment because of population structure. Here we develop a theory that allows us to study the synergistic interaction between direct reciprocity and assortment. This framework is particularly well suited for understanding human interactions, which are typically repeated and occur in relatively fluid but not unstructured populations. We show that if repeated games are combined with only a small amount of assortment, then natural selection favors the behavior typically observed among humans: high levels of cooperation implemented using conditional strategies. PMID:22665767

  18. Acoustic energy harvesting based on a planar acoustic metamaterial

    NASA Astrophysics Data System (ADS)

    Qi, Shuibao; Oudich, Mourad; Li, Yong; Assouar, Badreddine

    2016-06-01

    We theoretically report on an innovative and practical acoustic energy harvester based on a defected acoustic metamaterial (AMM) with piezoelectric material. The idea is to create suitable resonant defects in an AMM to confine the strain energy originating from an acoustic incidence. This scavenged energy is converted into electrical energy by attaching a structured piezoelectric material into the defect area of the AMM. We show an acoustic energy harvester based on a meta-structure capable of producing electrical power from an acoustic pressure. Numerical simulations are provided to analyze and elucidate the principles and the performances of the proposed system. A maximum output voltage of 1.3 V and a power density of 0.54 μW/cm3 are obtained at a frequency of 2257.5 Hz. The proposed concept should have broad applications on energy harvesting as well as on low-frequency sound isolation, since this system acts as both acoustic insulator and energy harvester.

  19. Influence of reciprocal links in social networks.

    PubMed

    Zhu, Yu-Xiao; Zhang, Xiao-Guang; Sun, Gui-Quan; Tang, Ming; Zhou, Tao; Zhang, Zi-Ke

    2014-01-01

    How does reciprocal links affect the function of real social network? Does reciprocal link and non-reciprocal link play the same role? Previous researches haven't displayed a clear picture to us until now according to the best of our knowledge. Motivated by this, in this paper, we empirically study the influence of reciprocal links in two representative real datasets, Sina Weibo and Douban. Our results demonstrate that the reciprocal links play a more important role than non-reciprocal ones in information diffusion process. In particular, not only coverage but also the speed of the information diffusion can be significantly enhanced by considering the reciprocal effect. We give some possible explanations from the perspectives of network connectivity and efficiency. This work may shed some light on the in-depth understanding and application of the reciprocal effect in directed online social networks. PMID:25072242

  20. Influence of Reciprocal Links in Social Networks

    PubMed Central

    Zhu, Yu-Xiao; Zhang, Xiao-Guang; Sun, Gui-Quan; Tang, Ming; Zhou, Tao; Zhang, Zi-Ke

    2014-01-01

    How does reciprocal links affect the function of real social network? Does reciprocal link and non-reciprocal link play the same role? Previous researches haven't displayed a clear picture to us until now according to the best of our knowledge. Motivated by this, in this paper, we empirically study the influence of reciprocal links in two representative real datasets, Sina Weibo and Douban. Our results demonstrate that the reciprocal links play a more important role than non-reciprocal ones in information diffusion process. In particular, not only coverage but also the speed of the information diffusion can be significantly enhanced by considering the reciprocal effect. We give some possible explanations from the perspectives of network connectivity and efficiency. This work may shed some light on the in-depth understanding and application of the reciprocal effect in directed online social networks. PMID:25072242

  1. Do infants detect indirect reciprocity?

    PubMed

    Meristo, Marek; Surian, Luca

    2013-10-01

    In social interactions involving indirect reciprocity, agent A acts prosocially towards B and this prompts C to act prosocially towards A. This happens because A's actions enhanced its reputation in the eyes of third parties. Indirect reciprocity may have been of central importance in the evolution of morality as one of the major mechanisms leading to the selection of helping and fair attitudes. Here we show that 10-month-old infants expect third parties to act positively towards fair donors who have distributed attractive resources equally between two recipients, rather than toward unfair donors who made unequal distributions. Infants' responses were dependent on the reciprocator's perceptual exposure to previous relevant events: they expected the reciprocator to reward the fair donor only when it had seen the distributive actions performed by the donors. We propose that infants were able to generate evaluations of agents that were based on the fairness of their distributive actions and to generate expectations about the social preferences of informed third parties. PMID:23887149

  2. Reciprocating Saw for Silicon Wafers

    NASA Technical Reports Server (NTRS)

    Morrison, A. D.; Collins, E. R., Jr.

    1985-01-01

    Concept increases productivity and wafer quality. Cutting wafers from silicon ingots produces smooth wafers at high rates with reduced blade wear. Involves straight reciprocating saw blade and slight rotation of ingot between cutting strokes. Many parallel blades combined to cut many wafers simultaneously from ingot.

  3. Thermal-powered reciprocating pump

    NASA Technical Reports Server (NTRS)

    Sabelman, E. E.

    1972-01-01

    Waste heat from radioisotope thermal generators in spacecraft is transported to keep instruments warm by two-cylinder reciprocating pump powered by energy from warm heat exchange fluid. Each cylinder has thermally nonconductive piston, heat exchange coil, and heat sink surface.

  4. Acoustic Neuroma

    MedlinePlus

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

  5. Acoustic Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

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

  6. Acoustic seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

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

  7. Capuchin Monkeys Judge Third-Party Reciprocity

    ERIC Educational Resources Information Center

    Anderson, James R.; Takimoto, Ayaka; Kuroshima, Hika; Fujita, Kazuo

    2013-01-01

    Increasing interest is being shown in how children develop an understanding of reciprocity in social exchanges and fairness in resource distribution, including social exchanges between third parties. Although there are descriptions of reciprocity on a one-to-one basis in other species, whether nonhumans detect reciprocity and violations of…

  8. Reciprocal Teaching: Critical Reflection on Practice

    ERIC Educational Resources Information Center

    McAllum, Ruth

    2014-01-01

    This paper highlights reciprocal teaching as an inclusive instructional strategy that has been shown to improve reading comprehension and metacognitive skills. It provides a conceptual background to reciprocal teaching and examines its purpose, strengths and weaknesses. The notion of reciprocal teaching as an evidence-based practice is also…

  9. Reciprocal relations based on the non-stationary Boltzmann equation

    NASA Astrophysics Data System (ADS)

    Sharipov, Felix

    2012-03-01

    The reciprocal relations for open gaseous systems are obtained on the basis of main properties of the non-stationary Boltzmann equation and gas-surface interaction law. It is shown that the main principles to derive the kinetic coefficients satisfying the reciprocal relations remain the same as those used for time-independent gaseous systems [F. Sharipov, Onsager-Casimir reciprocal relations based on the Boltzmann equation and gas-surface interaction law single gas, Phys. Rev. 73 (2006) 026110]. First, the kinetic coefficients are obtained from the entropy production expression; then it is proved that the coefficient matrix calculated for time reversed source functions is symmetric. The proof is based on the reversibility of the gas-gas and gas-surface interactions. Three examples of applications of the present theory are given. None of these examples can be treated in the frame of the classical Onsager-Casimir reciprocal relations, which are valid only in a particular case, when the kinetic coefficients are odd or even with respect to the time reversion. The approach is generalized for gaseous mixtures.

  10. Towards direct realisation of the SI unit of sound pressure in the audible hearing range based on optical free-field acoustic particle measurements

    NASA Astrophysics Data System (ADS)

    Koukoulas, Triantafillos; Piper, Ben

    2015-04-01

    Since the introduction of the International System of Units (the SI system) in 1960, weights, measures, standardised approaches, procedures, and protocols have been introduced, adapted, and extensively used. A major international effort and activity concentrate on the definition and traceability of the seven base SI units in terms of fundamental constants, and consequently those units that are derived from the base units. In airborne acoustical metrology and for the audible range of frequencies up to 20 kHz, the SI unit of sound pressure, the pascal, is realised indirectly and without any knowledge or measurement of the sound field. Though the principle of reciprocity was originally formulated by Lord Rayleigh nearly two centuries ago, it was devised in the 1940s and eventually became a calibration standard in the 1960s; however, it can only accommodate a limited number of acoustic sensors of specific types and dimensions. International standards determine the device sensitivity either through coupler or through free-field reciprocity but rely on the continuous availability of specific acoustical artefacts. Here, we show an optical method based on gated photon correlation spectroscopy that can measure sound pressures directly and absolutely in fully anechoic conditions, remotely, and without disturbing the propagating sound field. It neither relies on the availability or performance of any measurement artefact nor makes any assumptions of the device geometry and sound field characteristics. Most importantly, the required units of sound pressure and microphone sensitivity may now be experimentally realised, thus providing direct traceability to SI base units.

  11. Towards direct realisation of the SI unit of sound pressure in the audible hearing range based on optical free-field acoustic particle measurements

    SciTech Connect

    Koukoulas, Triantafillos Piper, Ben

    2015-04-20

    Since the introduction of the International System of Units (the SI system) in 1960, weights, measures, standardised approaches, procedures, and protocols have been introduced, adapted, and extensively used. A major international effort and activity concentrate on the definition and traceability of the seven base SI units in terms of fundamental constants, and consequently those units that are derived from the base units. In airborne acoustical metrology and for the audible range of frequencies up to 20 kHz, the SI unit of sound pressure, the pascal, is realised indirectly and without any knowledge or measurement of the sound field. Though the principle of reciprocity was originally formulated by Lord Rayleigh nearly two centuries ago, it was devised in the 1940s and eventually became a calibration standard in the 1960s; however, it can only accommodate a limited number of acoustic sensors of specific types and dimensions. International standards determine the device sensitivity either through coupler or through free-field reciprocity but rely on the continuous availability of specific acoustical artefacts. Here, we show an optical method based on gated photon correlation spectroscopy that can measure sound pressures directly and absolutely in fully anechoic conditions, remotely, and without disturbing the propagating sound field. It neither relies on the availability or performance of any measurement artefact nor makes any assumptions of the device geometry and sound field characteristics. Most importantly, the required units of sound pressure and microphone sensitivity may now be experimentally realised, thus providing direct traceability to SI base units.

  12. Marmoset monkeys evaluate third-party reciprocity

    PubMed Central

    Kawai, Nobuyuki; Yasue, Miyuki; Banno, Taku; Ichinohe, Noritaka

    2014-01-01

    Many non-human primates have been observed to reciprocate and to understand reciprocity in one-to-one social exchanges. A recent study demonstrated that capuchin monkeys are sensitive to both third-party reciprocity and violation of reciprocity; however, whether this sensitivity is a function of general intelligence, evidenced by their larger brain size relative to other primates, remains unclear. We hypothesized that highly pro-social primates, even with a relatively smaller brain, would be sensitive to others' reciprocity. Here, we show that common marmosets discriminated between human actors who reciprocated in social exchanges with others and those who did not. Monkeys accepted rewards less frequently from non-reciprocators than they did from reciprocators when the non-reciprocators had retained all food items, but they accepted rewards from both actors equally when they had observed reciprocal exchange between the actors. These results suggest that mechanisms to detect unfair reciprocity in third-party social exchanges do not require domain-general higher cognitive ability based on proportionally larger brains, but rather emerge from the cooperative and pro-social tendencies of species, and thereby suggest this ability evolved in multiple primate lineages. PMID:24850892

  13. Reciprocal food sharing in the vampire bat

    NASA Astrophysics Data System (ADS)

    Wilkinson, Gerald S.

    1984-03-01

    Behavioural reciprocity can be evolutionarily stable1-3. Initial increase in frequency depends, however, on reciprocal altruists interacting predominantly with other reciprocal altruists either by associating within kin groups or by having sufficient memory to recognize and not aid nonreciprocators. Theory thus suggests that reciprocity should evolve more easily among animals which live in kin groups. Data are available separating reciprocity from nepotism only for unrelated nonhuman animals4. Here, I show that food sharing by regurgitation of blood among wild vampire bats (Desmodus rotundus) depends equally and independently on degree of relatedness and an index of opportunity for recipro cation. That reciprocity operates within groups containing both kin and nonkin is supported further with data on the availability of blood-sharing occasions, estimates of the economics of shar ing blood, and experiments which show that unrelated bats will reciprocally exchange blood in captivity.

  14. Reciprocal uniparental disomy in yeast

    PubMed Central

    Andersen, Sabrina L.; Petes, Thomas D.

    2012-01-01

    In the diploid cells of most organisms, including humans, each chromosome is usually distinguishable from its partner homolog by multiple single-nucleotide polymorphisms. One common type of genetic alteration observed in tumor cells is uniparental disomy (UPD), in which a pair of homologous chromosomes are derived from a single parent, resulting in loss of heterozygosity for all single-nucleotide polymorphisms while maintaining diploidy. Somatic UPD events are usually explained as reflecting two consecutive nondisjunction events. Here we report a previously undescribed mode of chromosome segregation in Saccharomyces cerevisiae in which one cell division produces daughter cells with reciprocal UPD for the same pair of chromosomes without an aneuploid intermediate. One pair of sister chromatids is segregated into one daughter cell and the other pair is segregated into the other daughter cell, mimicking a meiotic chromosome segregation pattern. We term this process “reciprocal uniparental disomy.” PMID:22665764

  15. Piston reciprocating compressed air engine

    SciTech Connect

    Cestero, L.G.

    1987-03-24

    A compressed air engine is described comprising: (a). a reservoir of compressed air, (b). two power cylinders each containing a reciprocating piston connected to a crankshaft and flywheel, (c). a transfer cylinder which communicates with each power cylinder and the reservoir, and contains a reciprocating piston connected to the crankshaft, (d). valve means controlled by rotation of the crankshaft for supplying compressed air from the reservoir to each power cylinder and for exhausting compressed air from each power cylinder to the transfer cylinder, (e). valve means controlled by rotation of the crankshaft for supplying from the transfer cylinder to the reservoir compressed air supplied to the transfer cylinder on the exhaust strokes of the pistons of the power cylinders, and (f). an externally powered fan for assisting the exhaust of compressed air from each power cylinder to the transfer cylinder and from there to the compressed air reservoir.

  16. Genetic Architecture of Reciprocal CNVs

    PubMed Central

    Golzio, Christelle; Katsanis, Nicholas

    2013-01-01

    Copy number variants (CNVs) represent a frequent type of lesion in human genetic disorders that typically affects numerous genes simultaneously. This has raised the challenge of understanding which genes within a CNV drive clinical phenotypes. Although CNVs can arise by multiple mechanisms, a subset is driven by local genomic architecture permissive to recombination events that can lead to both deletions and duplications. Phenotypic analyses of patients with such reciprocal CNVs have revealed instances in which the phenotype is either identical or mirrored; strikingly, molecular studies have revealed that such phenotypes are often driven by reciprocal dosage defects of the same transcript. Here we explore how these observations can help the dissection of CNVs and inform the genetic architecture of CNV-induced disorders. PMID:23747035

  17. Determining Equilibrium Position For Acoustical Levitation

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Aveni, G.; Putterman, S.; Rudnick, J.

    1989-01-01

    Equilibrium position and orientation of acoustically-levitated weightless object determined by calibration technique on Earth. From calibration data, possible to calculate equilibrium position and orientation in presence of Earth gravitation. Sample not levitated acoustically during calibration. Technique relies on Boltzmann-Ehrenfest adiabatic-invariance principle. One converts resonant-frequency-shift data into data on normalized acoustical potential energy. Minimum of energy occurs at equilibrium point. From gradients of acoustical potential energy, one calculates acoustical restoring force or torque on objects as function of deviation from equilibrium position or orientation.

  18. Reciprocal relations between kinetic curves

    NASA Astrophysics Data System (ADS)

    Yablonsky, G. S.; Gorban, A. N.; Constales, D.; Galvita, V. V.; Marin, G. B.

    2011-01-01

    We study coupled irreversible processes. For linear or linearized kinetics with microreversibility, \\dot{x}=Kx , the kinetic operator K is symmetric in the entropic inner product. This form of Onsager's reciprocal relations implies that the shift in time, exp(Kt), is also a symmetric operator. This generates the reciprocity relations between the kinetic curves. For example, for the Master equation, if we start the process from the i-th pure state and measure the probability pj(t) of the j-th state (j≠i), and, similarly, measure pi(t) for the process, which starts at the j-th pure state, then the ratio of these two probabilities pj(t)/pi(t) is constant in time and coincides with the ratio of the equilibrium probabilities. We study similar and more general reciprocal relations between the kinetic curves. The experimental evidence provided as an example is from the reversible water gas shift reaction over iron oxide catalyst. The experimental data are obtained using Temporal Analysis of Products (TAP) pulse-response studies. These offer excellent confirmation within the experimental error.

  19. Best compression: Reciprocating or rotary?

    SciTech Connect

    Cahill, C.

    1997-07-01

    A compressor is a device used to increase the pressure of a compressible fluid. The inlet pressure can vary from a deep vacuum to a high positive pressure. The discharge pressure can range from subatmospheric levels to tens of thousands of pounds per square inch. Compressors come in numerous forms, but for oilfield applications there are two primary types, reciprocating and rotary. Both reciprocating and rotary compressors are grouped in the intermittent mode of compression. Intermittent is cyclic in nature, in that a specific quantity of gas is ingested by the compressor, acted upon and discharged before the cycle is repeated. Reciprocating compression is the most common form of compression used for oilfield applications. Rotary screw compressors have a long history but are relative newcomers to oilfield applications. The rotary screw compressor-technically a helical rotor compressor-dates back to 1878. That was when the first rotary screw was manufactured for the purpose of compressing air. Today thousands of rotary screw compression packages are being used throughout the world to compress natural gas.

  20. Acoustic techniques in nuclear safeguards

    SciTech Connect

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

    1995-07-01

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

  1. Acoustic methodology review

    NASA Technical Reports Server (NTRS)

    Schlegel, R. G.

    1982-01-01

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

  2. Topological Acoustics

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  3. Topological acoustics.

    PubMed

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

    2015-03-20

    The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers. PMID:25839273

  4. Violation of Bloch's Law that specifies reciprocity of intensity and duration with brief light flashes

    PubMed Central

    Greene, Ernest

    2013-01-01

    For more than a century researchers have been reporting that the visual impact of a very brief flash is determined by the quantity of photons that the flash delivers. This has been variously described as the Bunsen-Roscoe Law or Bloch's Law, often specified as reciprocity of intensity × duration. Prior research found no evidence for such reciprocity when microsecond-duration flashes from a light-emitting diode array were used to display the major contours of nameable shapes. The present work tested with flash durations ranging up to 100 ms and also found no reciprocity. This departure from classic principles might be due to the specific range of wavelengths of the light-emitting diodes and to a mesopic level of ambient light, which together would preclude activation of rods. The reciprocity of intensity and duration may only be valid with full dark adaptation and very dim flashes that activate rods. PMID:25165512

  5. Determining beam properties at an inaccessible plane using the reciprocity of atmospheric turbulence

    NASA Astrophysics Data System (ADS)

    Nelson, W.; Wu, C.; Davis, C. C.

    2015-09-01

    A turbulent, atmospheric channel can be considered to be reciprocal at any one instance in time. Reciprocity is a powerful property that can be used to compensate for the distortions caused by turbulence such as beam scintillation, spreading, and wander. Here we investigate the use of reciprocity in instances where a beam is propagated to an uncooperative target. Theoretical work [V. P. Lukin and M. I. Charnotskii , Sov. J. Quantum Electron., 12(5), 602 (1982)] has shown that reciprocity principles indicate that properties of the beam incident on a target fluctuate synchronously with the intensity distribution scattered from the target. Here we extend this purely analytical treatment using phase screen simulations. We show that there exists a correlation between the intensity imaged by the receiver and the field incident on the target. Furthermore, we demonstrate that the intensity at a specific location could be used to drive an adaptive optics system that corrects for atmospheric phase distortions.

  6. Scanning Tomographic Acoustic Microscopy

    NASA Astrophysics Data System (ADS)

    Wade, G.; Meyyappan, A.

    1988-07-01

    The technology for "seeing" with sound has an important and interesting history. Some of nature's creatures have been using sound waves for many millenia to image otherwise unobservable objects. The human species, lacking this natural ability, have overcome this deficiency by developing several different ultrasonic imaging techniques. acoustic microscopy is one such technique, which produces high resolution images of detailed structure of small objects in a non-destructive fashion. Two types of acoustic microscopes have evolved for industrial exploitation. They are the scanning laser acoustic microscope (SLAM) and the scanning acoustic microscope (SAM). In this paper, we review the principles of SLAM and describe how we use elements of SLAM to realize the scanning tomographic acoustic microscope (STAM). We describe the data acquisition process and the image reconstruction procedure. We also describe techniques to obtain projection data from different angles of wave incidence enabling us to reconstruct different planes of a complex specimen tomo-graphically. Our experimental results show that STAM is capable of producing high-quality high-resolution subsurface images.

  7. Acoustic neuroma

    MedlinePlus

    Vestibular schwannoma; Tumor - acoustic; Cerebellopontine angle tumor; Angle tumor ... 177. Battista RA. Gamma knife radiosurgery for vestibular schwannoma. Otolaryngol Clin North Am . 2009;42:635-654. ...

  8. Brillouin-scattering-induced transparency and non-reciprocal light storage

    PubMed Central

    Dong, Chun-Hua; Shen, Zhen; Zou, Chang-Ling; Zhang, Yan-Lei; Fu, Wei; Guo, Guang-Can

    2015-01-01

    Stimulated Brillouin scattering is a fundamental interaction between light and travelling acoustic waves and arises primarily from electrostriction and photoelastic effects, with an interaction strength several orders of magnitude greater than that of other relevant non-linear optical processes. Here we report an experimental demonstration of Brillouin-scattering-induced transparency in a high-quality whispering-gallery-mode optical microresonantor. The triply resonant Stimulated Brillouin scattering process underlying the Brillouin-scattering-induced transparency greatly enhances the light–acoustic interaction, enabling the storage of light as a coherent, circulating acoustic wave with a lifetime up to 10 μs. Furthermore, because of the phase-matching requirement, a circulating acoustic wave can only couple to light with a given propagation direction, leading to non-reciprocal light storage and retrieval. These unique features establish a new avenue towards integrated all-optical switching with low-power consumption, optical isolators and circulators. PMID:25648234

  9. Reciprocity and gyrotropism in magnetic resonance transduction

    SciTech Connect

    Tropp, James

    2006-12-15

    We give formulas for transduction in magnetic resonance - i.e., the appearance of an emf due to Larmor precession of spins - based upon the modified Lorentz reciprocity principle for gyrotropic (also called 'nonreciprocal') media, i.e., in which a susceptibility tensor is carried to its transpose by reversal of an external static field [cf., R. F. Harrington and A. T. Villeneuve IRE Trans. Microwave Theory and Technique MTT6, 308 (1958)]. Prior applications of reciprocity to magnetic resonance, despite much success, have ignored the gyrotropism which necessarily arises due to nuclear and/or unpaired electronic spins. For detection with linearly polarized fields, oscillating at the Larmor frequency, the emf is written in terms of a volume integral containing a product of two factors which we define as the antenna patterns, i.e. (H{sub 1x}{+-}iH{sub 1y}), where, e.g., for a single transceive antenna, the H's are just the spatially dependent oscillatory magnetic field strengths, per the application of some reference current at the antenna terminals, with the negative sign obtaining for transmission, and the positive for reception. Similar expressions hold for separate transmit and receive antennas; expressions are also given for circular polarization of the fields. We then exhibit a receive-only array antenna of two elements for magnetic resonance imaging of protons, which, due an intensity artifact arising from stray reactive coupling of the elements, produces, despite its own bilateral symmetry, asymmetric proton NMR images of a symmetric cylindrical phantom containing aqueous saline solution [J. Tropp and T. Schirmer, J. Magn. Reson. 151, 146 (2001)]. Modification of this two-port antenna, to function in transmit-receive mode, allows us to demonstrate highly nonreciprocal behavior: that is, to record images (of cylindrical test phantoms containing aqueous saline solution) whose appearance dramatically changes, when the roles of transmission and reception are

  10. Reciprocity and gyrotropism in magnetic resonance transduction

    NASA Astrophysics Data System (ADS)

    Tropp, James

    2006-12-01

    We give formulas for transduction in magnetic resonance—i.e., the appearance of an emf due to Larmor precession of spins—based upon the modified Lorentz reciprocity principle for gyrotropic (also called “nonreciprocal”) media, i.e., in which a susceptibility tensor is carried to its transpose by reversal of an external static field [cf., R. F. Harrington and A. T. Villeneuve IRE Trans. Microwave Theory and Technique MTT6, 308 (1958)]. Prior applications of reciprocity to magnetic resonance, despite much success, have ignored the gyrotropism which necessarily arises due to nuclear and/or unpaired electronic spins. For detection with linearly polarized fields, oscillating at the Larmor frequency, the emf is written in terms of a volume integral containing a product of two factors which we define as the antenna patterns, i.e., (H1x±iH1y) , where, e.g., for a single transceive antenna, the H ’s are just the spatially dependent oscillatory magnetic field strengths, per the application of some reference current at the antenna terminals, with the negative sign obtaining for transmission, and the positive for reception. Similar expressions hold for separate transmit and receive antennas; expressions are also given for circular polarization of the fields. We then exhibit a receive-only array antenna of two elements for magnetic resonance imaging of protons, which, due an intensity artifact arising from stray reactive coupling of the elements, produces, despite its own bilateral symmetry, asymmetric proton NMR images of a symmetric cylindrical phantom containing aqueous saline solution [J. Tropp and T. Schirmer, J. Magn. Reson. 151, 146 (2001)]. Modification of this two-port antenna, to function in transmit-receive mode, allows us to demonstrate highly nonreciprocal behavior: that is, to record images (of cylindrical test phantoms containing aqueous saline solution) whose appearance dramatically changes, when the roles of transmission and reception are swapped

  11. Evolution of spite through indirect reciprocity.

    PubMed Central

    Johnstone, Rufus A.; Bshary, Redouan

    2004-01-01

    How can cooperation persist in the face of a temptation to 'cheat'? Several recent papers have suggested that the answer may lie in indirect reciprocity. Altruistic individuals may benefit by eliciting altruism from observers, rather than (as in direct reciprocity) from the recipient of the aid they provide. Here, we point out that indirect reciprocity need not always favour cooperation; by contrast, it may support spiteful behaviour, which is costly for the both actor and recipient. Existing theory suggests spite is unlikely to persist, but we demonstrate that it may do so when spiteful individuals are less likely to incur aggression from observers (a negative form of indirect reciprocity). PMID:15347514

  12. Reciprocating motion of active deformable particles

    NASA Astrophysics Data System (ADS)

    Tarama, M.; Ohta, T.

    2016-05-01

    Reciprocating motion of an active deformable particle in a homogeneous medium is studied theoretically. For generality, we employ a simple model derived from symmetry considerations for the center-of-mass velocity and elliptical and triangular deformations in two dimensions. We carry out, for the first time, a systematic investigation of the reciprocating motion of a self-propelled particle. It is clarified that spontaneous breaking of the front-rear asymmetry is essential for the reciprocating motion. Moreover, two routes are found for the formation of the reciprocating motion. One is a bifurcation from a motionless stationary state. The other is destabilisation of an oscillatory rectilinear motion.

  13. Electrochemical Processes Enhanced by Acoustic Liquid Manipulation

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.

    2004-01-01

    Acoustic liquid manipulation is a family of techniques that employ the nonlinear acoustic effects of acoustic radiation pressure and acoustic streaming to manipulate the behavior of liquids. Researchers at the NASA Glenn Research Center are exploring new methods of manipulating liquids for a variety of space applications, and we have found that acoustic techniques may also be used in the normal Earth gravity environment to enhance the performance of existing fluid processes. Working in concert with the NASA Commercial Technology Office, the Great Lakes Industrial Technology Center, and Alchemitron Corporation (Elgin, IL), researchers at Glenn have applied nonlinear acoustic principles to industrial applications. Collaborating with Alchemitron Corporation, we have adapted the devices to create acoustic streaming in a conventional electroplating process.

  14. Hybrid internal combustion reciprocating engine

    SciTech Connect

    Gonzalez, C.

    1988-08-23

    This patent describes a hybrid type reciprocating internal combustion turbine fuel engine with combined spark ignition, torch-assisted to compression ignition modes comprising: a cylinder; a cylinder head mounted on the cylinder having a substantially planar inner surface; exhaust and inlet valves positioned in the head connected to corresponding exhaust and unthrottled inlet passages; a piston reciprocally mounted within the cylinder having a top surface thereon which surface in the top dead center position of the piston is in close proximity with the inner surface of the cylinder head; a substantially spherical precombustion chamber located in the head; a lineal passage tangentially joining the precombustion chamber with the inner surface of the cylinder head; a pilot fuel injector means and an igniter means both located in the precombustion chamber which inject and ignite a precharge; a main fuel injector means in the cylinder head; a bowl-shaped recess comprising the main combustion chamber located in the top surface of the piston in close proximity with the main injector means in the top dead center position with the lineal passage tangentially aligned with the main combustion chamber, whereby the burning gases exiting the precombustion chamber are directed into the main combustion chamber causing ignition therein.

  15. Hybrid internal combustion reciprocating engine

    SciTech Connect

    Gonzales, C.

    1986-06-17

    A hybrid type reciprocating internal combustion engine is described which consists of: a cylinder, a cylinder head mounted on the cylinder having a substantially planar inner surface; exhaust and inlet valves positioned in the head connected to corresponding exhaust and unthrottled inlet passages; a piston reciprocally mounted within the cylinder having a top surface thereon which surface in the top dead center position of the piston is in close proximity with the inner surface of the head; a precombustion chamber located in the head; a lineal passage tangentially joining the precombustion chamber with the inner surface of the cylinder head; a pilot fuel injector means and an igniter means both located in the precombustion chamber which inject and ignite a precharge; a main fuel injector means in the cylinder head; a bowl shaped recess comprising the main combustion chamber non-concentrically located in the top surface of the piston in close proximity with the main injector means in the top dead center position; a first ramp means located in the top surface of the piston tangentially joining the main combustion chamber recess and substantially aligned with the lineal passage, when the piston is approximately at the top dead center position, whereby the burning gases exiting the precombustion chamber are directed into the main combustion recess; and a second ramp means in the top surface of the piston laterally joining the first ramp means.

  16. Indirect reciprocity with trinary reputations.

    PubMed

    Tanabe, Shoma; Suzuki, Hideyuki; Masuda, Naoki

    2013-01-21

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs have been examined in great details. Most previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by analyzing a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equilibria composed of a homogeneous population or a heterogeneous population containing two types of players. Some results derived for the trinary reputation model are direct extensions of those for the binary model. However, we find that the trinary model allows cooperation under image scoring under some mild conditions. PMID:23123557

  17. Bipropellant propulsion with reciprocating pumps

    NASA Astrophysics Data System (ADS)

    Whitehead, John C.

    1993-06-01

    A pressure regulated gas generator rocket cycle with alternately pressurized pairs of reciprocating pumps offers thrust-on-demand operation with significantly lower inert mass than conventional spacecraft liquid propulsion systems. The operation of bipropellant feed systems with reciprocating pumps is explained, with consideration for both short and long term missions. There are several methods for startup and shutdown of this self-starting pump-fed system, with preference determined by thrust duty cycle and mission duration. Progress to date includes extensive development testing of components unique to this type of system, and several live tests with monopropellant hydrazine. Pneumatic pump control valves which render pistons and bellows automatically responsive to downstream liquid demand are significantly simpler than those described previously. A compact pumpset mounted to central liquid manifolds has a pair of oxidizer pumps pneumatically slaved to a pair of fuel pumps to reduce vibration. A warm gas pressure reducer for tank expulsion can eliminate any remaining need for inert gas storage.

  18. Reciprocity and the Emergence of Power Laws in Social Networks

    NASA Astrophysics Data System (ADS)

    Schnegg, Michael

    Research in network science has shown that many naturally occurring and technologically constructed networks are scale free, that means a power law degree distribution emerges from a growth model in which each new node attaches to the existing network with a probability proportional to its number of links (= degree). Little is known about whether the same principles of local attachment and global properties apply to societies as well. Empirical evidence from six ethnographic case studies shows that complex social networks have significantly lower scaling exponents γ ~ 1 than have been assumed in the past. Apparently humans do not only look for the most prominent players to play with. Moreover cooperation in humans is characterized through reciprocity, the tendency to give to those from whom one has received in the past. Both variables — reciprocity and the scaling exponent — are negatively correlated (r = -0.767, sig = 0.075). If we include this effect in simulations of growing networks, degree distributions emerge that are much closer to those empirically observed. While the proportion of nodes with small degrees decreases drastically as we introduce reciprocity, the scaling exponent is more robust and changes only when a relatively large proportion of attachment decisions follow this rule. If social networks are less scale free than previously assumed this has far reaching implications for policy makers, public health programs and marketing alike.

  19. Respectful, Responsible, and Reciprocal Ruralities Research: Approaching and Positioning Educational Research Differently within Australian Rural Communities

    ERIC Educational Resources Information Center

    Brown, Alice; Danaher, P. A.

    2012-01-01

    One approach that is helpful in framing and facilitating effective and ethical rural education research projects is centred on ensuring that researcher-participant relations are respectful, responsible and reciprocal, predicated on the shared principles of CHE (connectivity, humanness and empathy). This approach derives from a strengths-based…

  20. Implementing Reciprocal Teaching: Was It Effective?

    ERIC Educational Resources Information Center

    Al-Hilawani, Yasser A.; And Others

    This study was conducted to explore the relationship between teaching methods and students' grades at the college level. Subjects, 58 undergraduate students enrolled in 2 introductory education courses, were organized into groups and exposed to one of two teaching methods: the lecture format and reciprocal teaching. Reciprocal teaching engages…

  1. Reciprocal Tutoring: Design with Cognitive Load Sharing

    ERIC Educational Resources Information Center

    Chou, Chih-Yueh; Chan, Tak-Wai

    2016-01-01

    "Reciprocal tutoring," as reported in "Exploring the design of computer supports for reciprocal tutoring" (Chan and Chou 1997), has extended the meaning and scope of "intelligent tutoring" originally implemented in stand alone computers. This research is a follow-up to our studies on a "learning companion…

  2. 78 FR 53792 - Draft Guidance for Reciprocity

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... COMMISSION Draft Guidance for Reciprocity AGENCY: Nuclear Regulatory Commission. ACTION: Draft NUREG; request... for reciprocity. The NRC is requesting public comment on draft NUREG-1556, Volume 19, Revision 1...@nrc.gov . The draft NUREG-1556, Volume 19, Revision 1, is available under ADAMS Accession...

  3. Reciprocal Teaching. Information Capsule. Volume 0609

    ERIC Educational Resources Information Center

    Blazer, Christie

    2007-01-01

    Reciprocal teaching is an instructional approach designed to increase students' reading comprehension at all grade levels and in all subject areas. Students are taught cognitive strategies that help them construct meaning from text and simultaneously monitor their reading comprehension. This Information Capsule summarizes reciprocal teaching's…

  4. Reciprocal Contracting with Families of Adolescents.

    ERIC Educational Resources Information Center

    Lipinski, Judith M.; Lawrence, P. Scott

    The use of reciprocal behavior contracts with families of behavior-problem adolescents was investigated. Most family contracting to date has involved one-way contracts; that is, the child agrees to certain responsibilities for which he will be reinforced by the parents. A reciprocal contract requires the parents, in addition to the child, to agree…

  5. Overview of geometrical room acoustic modeling techniques.

    PubMed

    Savioja, Lauri; Svensson, U Peter

    2015-08-01

    Computerized room acoustics modeling has been practiced for almost 50 years up to date. These modeling techniques play an important role in room acoustic design nowadays, often including auralization, but can also help in the construction of virtual environments for such applications as computer games, cognitive research, and training. This overview describes the main principles, landmarks in the development, and state-of-the-art for techniques that are based on geometrical acoustics principles. A focus is given to their capabilities to model the different aspects of sound propagation: specular vs diffuse reflections, and diffraction. PMID:26328688

  6. Room Acoustics

    NASA Astrophysics Data System (ADS)

    Kuttruff, Heinrich; Mommertz, Eckard

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

  7. Acoustic Neuroma

    MedlinePlus

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

  8. Underwater Acoustics

    NASA Astrophysics Data System (ADS)

    Kuperman, William A.; Roux, Philippe

    It is well underwater established that sound waves, compared to electromagnetic waves, propagate long distances in the ocean. Hence, in the ocean as opposed to air or a vacuum, one uses sound navigation and ranging (SONAR) instead navigation and ranging (SONAR) of radar, acoustic communication instead of radio, and acoustic imaging and tomography instead of microwave or optical imaging or X-ray tomography. Underwater acoustics is the science of sound in water (most commonly in the ocean) and encompasses not only the study of sound propagation, but also the masking of sound signals by interfering phenomenon and signal processing for extracting these signals from interference. This chapter we will present the basics physics of ocean acoustics and then discuss applications.

  9. Onsager's reciprocal relations in electrolyte solutions. I. Sedimentation and electroacoustics

    NASA Astrophysics Data System (ADS)

    Gourdin-Bertin, S.; Chassagne, C.; Bernard, O.; Jardat, M.

    2015-08-01

    In the framework of irreversible thermodynamics, we show that the sedimentation current in electrolyte solutions is mathematically equivalent to the low frequency limit of the ionic vibration current, appearing in the presence of an acoustic wave. This non-trivial result is obtained thanks to a careful choice of the reference frame used to express the mass fluxes in the context of electroacoustics. Coupled transport phenomena in electrolyte solutions can also be investigated in a mechanical framework, with a set of Newtonian equations for the dynamics of charged solutes. Both in the context of sedimentation and of electroacoustics, we show that the results obtained in the mechanical framework, in the ideal case (i.e., without interactions between ions), do satisfy the Onsager's reciprocal relations. We also derive the general relation between corrective forces accounting for ionic interactions which must be fulfilled so that the Onsager's reciprocal relations are verified. Finally, we show that no additional diffusion term needs to be taken into account in the flux of solutes (far from the walls), even if local concentration gradients exist, contrarily to what was done previously in the literature.

  10. Reciprocity breaking during nonlinear propagation of adapted beams through random media

    NASA Astrophysics Data System (ADS)

    Palastro, J. P.; Peñano, J.; Nelson, W.; DiComo, G.; Helle, M.; Johnson, L. A.; Hafizi, B.

    2016-08-01

    Adaptive optics (AO) systems rely on the principle of reciprocity, or symmetry with respect to the interchange of point sources and receivers. These systems use the light received from a low power emitter on or near a target to compensate profile aberrations acquired by a laser beam during linear propagation through random media. If, however, the laser beam propagates nonlinearly, reciprocity is broken, potentially undermining AO correction. Here we examine the consequences of this breakdown. While discussed for general random and nonlinear media, we consider specific examples of Kerr-nonlinear, turbulent atmosphere.

  11. Reciprocity breaking during nonlinear propagation of adapted beams through random media.

    PubMed

    Palastro, J P; Peñano, J; Nelson, W; DiComo, G; Helle, M; Johnson, L A; Hafizi, B

    2016-08-22

    Adaptive optics (AO) systems rely on the principle of reciprocity, or symmetry with respect to the interchange of point sources and receivers. These systems use the light received from a low power emitter on or near a target to compensate phase aberrations acquired by a laser beam during linear propagation through random media. If, however, the laser beam propagates nonlinearly, reciprocity is broken, potentially undermining AO correction. Here we examine the consequences of this breakdown, providing the first analysis of AO applied to high peak power laser beams. While discussed for general random and nonlinear media, we consider specific examples of Kerr-nonlinear, turbulent atmosphere. PMID:27557166

  12. Reciprocity of agonistic support in ravens

    PubMed Central

    Fraser, Orlaith N.; Bugnyar, Thomas

    2012-01-01

    Cooperative behaviour through reciprocation or interchange of valuable services in primates has received considerable attention, especially regarding the timeframe of reciprocation and its ensuing cognitive implications. Much less, however, is known about reciprocity in other animals, particularly birds. We investigated patterns of agonistic support (defined as a third party intervening in an ongoing conflict to attack one of the conflict participants, thus supporting the other) in a group of 13 captive ravens, Corvus corax. We found support for long-term, but not short-term, reciprocation of agonistic support. Ravens were more likely to support individuals who preened them, kin and dominant group members. These results suggest that ravens do not reciprocate on a calculated tit-for-tat basis, but aid individuals from whom reciprocated support would be most useful and those with whom they share a good relationship. Additionally, dyadic levels of agonistic support and consolation (postconflict affiliation from a bystander to the victim) correlated strongly with each other, but we found no evidence to suggest that receiving agonistic support influences the victim’s likelihood of receiving support (consolation) after the conflict ends. Our findings are consistent with an emotionally mediated form of reciprocity in ravens and provide additional support for convergent cognitive evolution in birds and mammals. PMID:22298910

  13. Reciprocity of agonistic support in ravens.

    PubMed

    Fraser, Orlaith N; Bugnyar, Thomas

    2012-01-01

    Cooperative behaviour through reciprocation or interchange of valuable services in primates has received considerable attention, especially regarding the timeframe of reciprocation and its ensuing cognitive implications. Much less, however, is known about reciprocity in other animals, particularly birds. We investigated patterns of agonistic support (defined as a third party intervening in an ongoing conflict to attack one of the conflict participants, thus supporting the other) in a group of 13 captive ravens, Corvus corax. We found support for long-term, but not short-term, reciprocation of agonistic support. Ravens were more likely to support individuals who preened them, kin and dominant group members. These results suggest that ravens do not reciprocate on a calculated tit-for-tat basis, but aid individuals from whom reciprocated support would be most useful and those with whom they share a good relationship. Additionally, dyadic levels of agonistic support and consolation (postconflict affiliation from a bystander to the victim) correlated strongly with each other, but we found no evidence to suggest that receiving agonistic support influences the victim's likelihood of receiving support (consolation) after the conflict ends. Our findings are consistent with an emotionally mediated form of reciprocity in ravens and provide additional support for convergent cognitive evolution in birds and mammals. PMID:22298910

  14. Two distinct neural mechanisms underlying indirect reciprocity.

    PubMed

    Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

    2014-03-18

    Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards. PMID:24591599

  15. Two distinct neural mechanisms underlying indirect reciprocity

    PubMed Central

    Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

    2014-01-01

    Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards. PMID:24591599

  16. ADVANCED RECIPROCATING COMPRESSION TECHNOLOGY (ARCT)

    SciTech Connect

    Danny M. Deffenbaugh; Klaus Brun; Ralph E. Harris; J. Pete Harrell; Robert J. Mckee; J. Jeffrey Moore; Steven J. Svedeman; Anthony J. Smalley; Eugene L. Broerman; Robert A Hart; Marybeth G. Nored; Ryan S. Gernentz; Shane P. Siebenaler

    2005-12-01

    The U.S. natural gas pipeline industry is facing the twin challenges of increased flexibility and capacity expansion. To meet these challenges, the industry requires improved choices in gas compression to address new construction and enhancement of the currently installed infrastructure. The current fleet of installed reciprocating compression is primarily slow-speed integral machines. Most new reciprocating compression is and will be large, high-speed separable units. The major challenges with the fleet of slow-speed integral machines are: limited flexibility and a large range in performance. In an attempt to increase flexibility, many operators are choosing to single-act cylinders, which are causing reduced reliability and integrity. While the best performing units in the fleet exhibit thermal efficiencies between 90% and 92%, the low performers are running down to 50% with the mean at about 80%. The major cause for this large disparity is due to installation losses in the pulsation control system. In the better performers, the losses are about evenly split between installation losses and valve losses. The major challenges for high-speed machines are: cylinder nozzle pulsations, mechanical vibrations due to cylinder stretch, short valve life, and low thermal performance. To shift nozzle pulsation to higher orders, nozzles are shortened, and to dampen the amplitudes, orifices are added. The shortened nozzles result in mechanical coupling with the cylinder, thereby, causing increased vibration due to the cylinder stretch mode. Valve life is even shorter than for slow speeds and can be on the order of a few months. The thermal efficiency is 10% to 15% lower than slow-speed equipment with the best performance in the 75% to 80% range. The goal of this advanced reciprocating compression program is to develop the technology for both high speed and low speed compression that will expand unit flexibility, increase thermal efficiency, and increase reliability and integrity

  17. Self-reciprocating radioisotope-powered cantilever

    NASA Astrophysics Data System (ADS)

    Li, Hui; Lal, Amit; Blanchard, James; Henderson, Douglass

    2002-07-01

    A reciprocating cantilever utilizing emitted charges from a millicurie radioisotope thin film is presented. The actuator realizes a direct collected-charge-to-motion conversion. The reciprocation is obtained by self-timed contact between the cantilever and the radioisotope source. A static model balancing the electrostatic and mechanical forces from an equivalent circuit leads to an analytical solution useful for device characterization. Measured reciprocating periods agree with predicted values from the analytical model. A scaling analysis shows that microscale arrays of such cantilevers provide an integrated sensor and actuator platform.

  18. Acoustic biosensors

    PubMed Central

    Fogel, Ronen; Seshia, Ashwin A.

    2016-01-01

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

  19. Acoustic biosensors.

    PubMed

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

    2016-06-30

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

  20. Bernoulli's Principle

    ERIC Educational Resources Information Center

    Hewitt, Paul G.

    2004-01-01

    Some teachers have difficulty understanding Bernoulli's principle particularly when the principle is applied to the aerodynamic lift. Some teachers favor using Newton's laws instead of Bernoulli's principle to explain the physics behind lift. Some also consider Bernoulli's principle too difficult to explain to students and avoid teaching it…

  1. Reciprocity-based experimental determination of dynamic forces and moments: A feasibility study

    NASA Technical Reports Server (NTRS)

    Ver, Istvan L.; Howe, Michael S.

    1994-01-01

    BBN Systems and Technologies has been tasked by the Georgia Tech Research Center to carry Task Assignment No. 7 for the NASA Langley Research Center to explore the feasibility of 'In-Situ Experimental Evaluation of the Source Strength of Complex Vibration Sources Utilizing Reciprocity.' The task was carried out under NASA Contract No. NAS1-19061. In flight it is not feasible to connect the vibration sources to their mounting points on the fuselage through force gauges to measure dynamic forces and moments directly. However, it is possible to measure the interior sound field or vibration response caused by these structureborne sound sources at many locations and invoke principle of reciprocity to predict the dynamic forces and moments. The work carried out in the framework of Task 7 was directed to explore the feasibility of reciprocity-based measurements of vibration forces and moments.

  2. Electronic controller for reciprocating rotary crystallizer

    NASA Technical Reports Server (NTRS)

    Kroes, Roger L.; Reiss, Donald A.; Hester, Howard B.

    1988-01-01

    An electronic controller for a reciprocating rotary crystallizer is described. The heart of this system is the electronic timer circuit. A schematic along with a detailed description of its operation is given.

  3. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  4. 30 CFR 57.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Reciprocating-type air compressors. 57.13010... Air and Boilers § 57.13010 Reciprocating-type air compressors. (a) Reciprocating-type air compressors... than 25 percent. (b) However, this standard does not apply to reciprocating-type air compressors...

  5. 32 CFR 148.1 - Intergency reciprocal acceptance .

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Intergency reciprocal acceptance . 148.1 Section... Reciprocity of Use and Inspections of Facilities § 148.1 Intergency reciprocal acceptance . Interagency reciprocal acceptance of security policies and procedures for approving, accrediting, and maintaining...

  6. 32 CFR 148.1 - Intergency reciprocal acceptance .

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Intergency reciprocal acceptance . 148.1 Section... Reciprocity of Use and Inspections of Facilities § 148.1 Intergency reciprocal acceptance . Interagency reciprocal acceptance of security policies and procedures for approving, accrediting, and maintaining...

  7. A wireless interrogation system exploiting narrowband acoustic resonator for remote physical quantity measurement

    NASA Astrophysics Data System (ADS)

    Friedt, J.-M.; Droit, C.; Martin, G.; Ballandras, S.

    2010-01-01

    Monitoring physical quantities using acoustic wave devices can be advantageously achieved using the wave characteristic dependence to various parametric perturbations (temperature, stress, and pressure). Surface acoustic wave (SAW) resonators are particularly well suited to such applications as their resonance frequency is directly influenced by these perturbations, modifying both the phase velocity and resonance conditions. Moreover, the intrinsic radio frequency (rf) nature of these devices makes them ideal for wireless applications, mainly exploiting antennas reciprocity and piezoelectric reversibility. In this paper, we present a wireless SAW sensor interrogation unit operating in the 434 MHz centered ISM band—selected as a tradeoff between antenna dimensions and electromagnetic wave penetration in dielectric media—based on the principles of a frequency sweep network analyzer. We particularly focus on the compliance with the ISM standard which reveals complicated by the need for switching from emission to reception modes similarly to radar operation. In this matter, we propose a fully digital rf synthesis chain to develop various interrogation strategies to overcome the corresponding difficulties and comply with the above-mentioned standard. We finally assess the reader interrogation range, accuracy, and dynamics.

  8. Fast wideband acoustical holography.

    PubMed

    Hald, Jørgen

    2016-04-01

    Patch near-field acoustical holography methods like statistically optimized near-field acoustical holography and equivalent source method are limited to relatively low frequencies, where the average array-element spacing is less than half of the acoustic wavelength, while beamforming provides useful resolution only at medium-to-high frequencies. With adequate array design, both methods can be used with the same array. But for holography to provide good low-frequency resolution, a small measurement distance is needed, whereas beamforming requires a larger distance to limit sidelobe issues. The wideband holography method of the present paper was developed to overcome that practical conflict. Only a single measurement is needed at a relatively short distance and a single result is obtained covering the full frequency range. The method uses the principles of compressed sensing: A sparse sound field representation is assumed with a chosen set of basis functions, a measurement is taken with an irregular array, and the inverse problem is solved with a method that enforces sparsity in the coefficient vector. Instead of using regularization based on the 1-norm of the coefficient vector, an iterative solution procedure is used that promotes sparsity. The iterative method is shown to provide very similar results in most cases and to be computationally much more efficient. PMID:27106299

  9. The reciprocity theorem for the scattered field is the progenitor of the generalized optical theorem.

    PubMed

    Douma, Huub; Vasconcelos, Ivan; Snieder, Roel

    2011-05-01

    By analyzing correlation-type reciprocity theorems for wavefields in perturbed media, it is shown that the correlation-type reciprocity theorem for the scattered field is the progenitor of the generalized optical theorem. This reciprocity theorem, in contrast to the generalized optical theorem, allows for inhomogeneous background properties and does not make use of a far-field condition. This theorem specializes to the generalized optical theorem when considering a finite-size scatterer embedded in a homogeneous background medium and when utilizing the far-field condition. Moreover, it is shown that the reciprocity theorem for the scattered field is responsible for the cancellation of non-physical (spurious) arrivals in seismic interferometry, and as such provides the mathematical description of such arrivals. Even though here only acoustic waves are treated, the presented treatment is not limited to such wavefields and can be generalized to general wavefields. Therefore, this work provides the framework for deriving equivalents of the generalized optical theorem for general wavefields. PMID:21568381

  10. Acoustic velocity meter systems

    USGS Publications Warehouse

    Laenen, Antonius

    1985-01-01

    Acoustic velocity meter (AVM) systems operate on the principles that the point-to-point upstream traveltime of an acoustic pulse is longer than the downstream traveltime and that this difference in traveltime can be accurately measured by electronic devices. An AVM system is capable of recording water velocity (and discharge) under a wide range of conditions, but some constraints apply: 1. Accuracy is reduced and performance is degraded if the acoustic path is not a continuous straight line. The path can be bent by reflection if it is too close to a stream boundary or by refraction if it passes through density gradients resulting from variations in either water temperature or salinity. For paths of less than 100 m, a temperature gradient of 0.1' per meter causes signal bending less than 0.6 meter at midchannel, and satisfactory velocity results can be obtained. Reflection from stream boundaries can cause signal cancellation if boundaries are too close to signal path. 2. Signal strength is attenuated by particles or bubbles that absorb, spread, or scatter sound. The concentration of particles or bubbles that can be tolerated is a function of the path length and frequency of the acoustic signal. 3. Changes in streamline orientation can affect system accuracy if the variability is random. 4. Errors relating to signal resolution are much larger for a single threshold detection scheme than for multiple threshold schemes. This report provides methods for computing the effect of various conditions on the accuracy of a record obtained from an AVM. The equipment must be adapted to the site. Field reconnaissance and preinstallation analysis to detect possible problems are critical for proper installation and operation of an AVM system.

  11. The Evaluational Consequences of Topic Reciprocity and Self-Disclosure Reciprocity.

    ERIC Educational Resources Information Center

    Hosman, Lawrence A.

    1987-01-01

    Investigates the hypothesis that messages reciprocating both topic and intimacy would be more positively evaluated than those reciprocating neither. Results support the hypothesis for initial low intimacy messages, and partially support it for initial high intimacy messages. Examines results in terms of competing interactional goals in a…

  12. Acoustic transducer for acoustic microscopy

    DOEpatents

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

    1990-01-01

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

  13. Acoustic transducer for acoustic microscopy

    DOEpatents

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

    1990-03-20

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

  14. Quadratic Reciprocity and the Group Orders of Particle States

    SciTech Connect

    DAI,YANG; BORISOV,ALEXEY B.; LONGWORTH,JAMES W.; BOYER,KEITH; RHODES,CHARLES K.

    2001-06-01

    The construction of inverse states in a finite field F{sub P{sub P{alpha}}} enables the organization of the mass scale by associating particle states with residue class designations. With the assumption of perfect flatness ({Omega}total = 1.0), this approach leads to the derivation of a cosmic seesaw congruence which unifies the concepts of space and mass. The law of quadratic reciprocity profoundly constrains the subgroup structure of the multiplicative group of units F{sub P{sub {alpha}}}* defined by the field. Four specific outcomes of this organization are (1) a reduction in the computational complexity of the mass state distribution by a factor of {approximately}10{sup 30}, (2) the extension of the genetic divisor concept to the classification of subgroup orders, (3) the derivation of a simple numerical test for any prospective mass number based on the order of the integer, and (4) the identification of direct biological analogies to taxonomy and regulatory networks characteristic of cellular metabolism, tumor suppression, immunology, and evolution. It is generally concluded that the organizing principle legislated by the alliance of quadratic reciprocity with the cosmic seesaw creates a universal optimized structure that functions in the regulation of a broad range of complex phenomena.

  15. Onsager's Variational Principle in Soft Matter Dynamics

    NASA Astrophysics Data System (ADS)

    Doi, Masao

    2012-02-01

    It is shown that Onsager's variational principle gives us a unified frame-work in discussing various dynamics of soft matter such as diffusion, rheology and their coupling. The variational principle gives kinetic equations which satisfy Onsager's reciprocal relation. With many examples, it is shown that the kinetic equations are usually written as non-linear partial differential equations for state variables and can describe various non-linear and non-equilibrium phenomena in soft matter. The physics underlying the variational principle is discussed.

  16. Medical Acoustics

    NASA Astrophysics Data System (ADS)

    Beach, Kirk; Dunmire, Barbrina

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

  17. Acoustic chaos

    SciTech Connect

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

    1996-06-01

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

  18. Acoustic radiation stress in solids

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Yost, William T.

    1986-01-01

    It is shown that the radiation-induced static strains associated with acoustic waves propagating in solids are obtained directly from the virial theorem for an elastic continuum and that the radiation stresses result from combining the virial theorem with the Boltzmann-Ehrenfest principle of adiabatic invariance. The experimental confirmation of critical theoretical predictions in solids is reported. The implications of the results for the fundamental thermal properties of crystals are addressed.

  19. Theory of reciprocating contact for viscoelastic solids

    NASA Astrophysics Data System (ADS)

    Putignano, Carmine; Carbone, Giuseppe; Dini, Daniele

    2016-04-01

    A theory of reciprocating contacts for linear viscoelastic materials is presented. Results are discussed for the case of a rigid sphere sinusoidally driven in sliding contact with a viscoelastic half-space. Depending on the size of the contact, the frequency and amplitude of the reciprocating motion, and on the relaxation time of the viscoelastic body, we establish that the contact behavior may range from the steady-state viscoelastic solution, in which traction forces always oppose the direction of the sliding rigid punch, to a more elaborate trend, which is due to the strong interaction between different regions of the path covered during the reciprocating motion. Practical implications span a number of applications, ranging from seismic engineering to biotechnology.

  20. Reciprocation and altruism in social cooperation.

    PubMed

    Safin, Vasiliy; Arfer, Kodi B; Rachlin, Howard

    2015-07-01

    Altruistic behavior benefits other individuals at a cost to oneself. The purpose of the present experiment was to study altruistic behavior by players (P) in 2-person iterated prisoner's dilemma games in which reciprocation by the other player (OP) was impossible, and this impossibility was clear to P. Altruism by P could not therefore be attributed to expectation of reciprocation. The cost to P of altruistic behavior was constant throughout the study, but the benefit to OP from P's cooperation differed between groups and conditions. Rate of cooperation was higher when benefit to OP was higher. Thus altruism (not attributable to expectation of reciprocation) can be a significant factor in interpersonal relationships as studied in iterated prisoner's dilemma games, and needs to be taken into account in their analysis. PMID:25907149

  1. Modelling fluid flow in a reciprocating compressor

    NASA Astrophysics Data System (ADS)

    Tuhovcak, Jan; Hejčík, Jiří; Jícha, Miroslav

    2015-05-01

    Efficiency of reciprocating compressor is strongly dependent on the valves characteristics, which affects the flow through the suction and discharge line. Understanding the phenomenon inside the compressor is necessary step in development process. Commercial CFD tools offer wide capabilities to simulate the flow inside the reciprocating compressor, however they are too complicated in terms of computational time and mesh creation. Several parameters describing compressor could be therefore examined without the CFD analysis, such is valve characteristic, flow through the cycle and heat transfer. The aim of this paper is to show a numerical tool for reciprocating compressor based on the energy balance through the cycle, which provides valve characteristics, flow through the cycle and heat losses from the cylinder. Spring-damping-mass model was used for the valve description. Boundary conditions were extracted from the performance test of 4-cylinder semihermetic compressor and numerical tool validation was performed with indicated p-V diagram comparison.

  2. Fisher information, the Hellmann-Feynman theorem, and the Jaynes reciprocity relations

    SciTech Connect

    Flego, S.P.; Plastino, A.; Plastino, A.R.

    2011-10-15

    We explore intriguing links connecting Hellmann-Feynman's theorem to a thermodynamics information-optimizing principle based on Fisher's information measure. - Highlights: > We link a purely quantum mechanical result, the Hellmann-Feynman theorem, with Jaynes' information theoretical reciprocity relations. > These relations involve the coefficients of a series expansion of the potential function. > We suggest the existence of a Legendre transform structure behind Schroedinger's equation, akin to the one characterizing thermodynamics.

  3. Reciprocating Feed System Development Status

    NASA Technical Reports Server (NTRS)

    Trewek, Mary (Technical Monitor); Blackmon, James B.; Eddleman, David E.

    2005-01-01

    The reciprocating feed system (RFS) is an alternative means of providing high pressure propellant flow at low cost and system mass, with high fail-operational reliability. The RFS functions by storing the liquid propellants in large, low-pressure tanks and then expelling each propellant through two or three small, high-pressure tanks. Each RFS tank is sequentially filled, pressurized, expelled, vented, and refilled so as to provide a constant, or variable, mass flow rate to the engine. This type of system is much lighter than a conventional pressure fed system in part due to the greatly reduced amount of inert tank weight. The delivered payload for an RFS is superior to that of conventional pressure fed systems for conditions of high total impulse and it is competitive with turbopump systems, up to approximately 2000 psi. An advanced version of the RFS uses autogenous pressurization and thrust augmentation to achieve higher performance. In this version, the pressurization gases are combusted in a small engine, thus making the pressurization system, in effect, part of the propulsion system. The RFS appears to be much less expensive than a turbopump system, due to reduced research and development cost and hardware cost, since it is basically composed of small high- pressure tanks, a pressurization system, and control valves. A major benefit is the high reliability fail-operational mode; in the event of a failure in one of the three tank-systems, it can operate on the two remaining tanks. Other benefits include variable pressure and flow rates, ease of engine restart in micro-gravity, and enhanced propellant acquisition and control under adverse acceleration conditions. We present a system mass analysis tool that accepts user inputs for various design and mission parameters and calculates such output values payload and vehicle weights for the conventional pressure fed system, the RFS, the Autogenous Pressurization Thrust Augmentation (APTA) RFS, and turbopump systems

  4. The Effects of Reciprocal Teaching and Direct Instruction Approaches on Knowledge Map (K-Map) Generation Skill

    ERIC Educational Resources Information Center

    Görgen, Izzet

    2014-01-01

    The primary purpose of the present study is to investigate whether reciprocal teaching approach or direct instruction approach is more effective in the teaching of k-map generation skill. Secondary purpose of the study is to determine which of the k-map generation principles are more challenging for students to apply. The results of the study…

  5. The Effects of Reciprocal Teaching and Direct Instruction Approaches on Knowledge Map (k-map) Generation Skill

    ERIC Educational Resources Information Center

    Gorgen, Izzet

    2014-01-01

    The primary purpose of the present study is to investigate whether reciprocal teaching approach or direct instruction approach is more effective in the teaching of k-map generation skill. Secondary purpose of the study is to determine which of the k-map generation principles are more challenging for students to apply. The results of the study…

  6. Feasibility analysis of reciprocating magnetic heat pumps

    NASA Technical Reports Server (NTRS)

    Larson, A. V.; Hartley, J. G.; Shelton, Sam V.; Smith, M. M.

    1989-01-01

    A reciprocating gadolinium core in a regeneration fluid column in the warm bore of a superconducting solenoidal magnet is considered for magnetic refrigeration in 3.517 MW (1000 ton) applications. A procedure is presented to minimize the amount of superconducting cable needed in the magnet design. Estimated system capital costs for an ideal magnetic refrigerator of this type become comparable to conventional chillers as the frequency of reciprocation approaches 10 Hertz. A 1-D finite difference analysis of a regenerator cycling at 0.027 Hertz is presented which exhibits some of the features seen in the experiments of G. V. Brown.

  7. Acoustic Tooth Cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.

    1984-01-01

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

  8. Tuition Reciprocity in the United States

    ERIC Educational Resources Information Center

    Stewart, Gregory; Wright, Dianne Brown; Kennedy, Angelica

    2008-01-01

    Reciprocity agreements are contracts between two or more parties whereby students pay reduced tuition rates. The rate of reduction is determined by the parameters set forth in each individual state's agreement but may range from a modest reduction in fees to a waiver of full non-resident tuition. In addition to providing tuition relief,…

  9. Evolving the ingredients for reciprocity and spite

    PubMed Central

    Hauser, Marc; McAuliffe, Katherine; Blake, Peter R.

    2009-01-01

    Darwin never provided a satisfactory account of altruism, but posed the problem beautifully in light of the logic of natural selection. Hamilton and Williams delivered the necessary satisfaction by appealing to kinship, and Trivers showed that kinship was not necessary as long as the originally altruistic act was conditionally reciprocated. From the late 1970s to the present, the kinship theories in particular have been supported by considerable empirical data and elaborated to explore a number of other social interactions such as cooperation, selfishness and punishment, giving us what is now a rich description of the nature of social relationships among organisms. There are, however, two forms of theoretically possible social interactions—reciprocity and spite—that appear absent or nearly so in non-human vertebrates, despite considerable research efforts on a wide diversity of species. We suggest that the rather weak comparative evidence for these interactions is predicted once we consider the requisite socioecological pressures and psychological mechanisms. That is, a consideration of ultimate demands and proximate prerequisites leads to the prediction that reciprocity and spite should be rare in non-human animals, and common in humans. In particular, reciprocity and spite evolved in humans because of adaptive demands on cooperation among unrelated individuals living in large groups, and the integrative capacities of inequity detection, future-oriented decision-making and inhibitory control. PMID:19805432

  10. Reciprocal Teaching. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2013

    2013-01-01

    "Reciprocal teaching" is an instructional method designed to help teach reading comprehension skills to students with adequate decoding proficiency. During initial instructional sessions, the teacher introduces four comprehension strategies: summarizing, questioning, clarifying, and predicting. Then, the teacher and student read several…

  11. Development of Trust and Reciprocity in Adolescence

    ERIC Educational Resources Information Center

    van den Bos, Wouter; Westenberg, Michiel; van Dijk, Eric; Crone, Eveline A.

    2010-01-01

    We investigate the development of two types of prosocial behavior, trust and reciprocity, as defined using a game-theoretical task that allows investigation of real-time social interaction, among 4 age groups from 9 to 25 years. By manipulating the possible outcome alternatives, we could distinguish among important determinants of trust and…

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  13. Phonon Diodes and Transistors from Magneto-acoustics

    NASA Astrophysics Data System (ADS)

    Sklan, Sophia; Grossman, Jeffrey

    2014-03-01

    The creation of non-reciprocal phononic systems holds the promise of allowing computers that would process thermal or acoustic (rather than electronic) signals. By sculpting the magnetic field applied to magneto-acoustic materials (which couple phonons to a magnetic field, typically due to effects like magnon-phonon coupling in yttrium iron garnet), phonons can be used for information processing in analogy with photonic computing. Using a combination of analytic and numerical techniques, we demonstrate designs for diodes (isolators) and transistors that are independent of their conventional, electronic formulation. We analyze the experimental feasibility of these systems, including the sensitivity of the circuits to likely systematic and random errors.

  14. Buridan's Principle

    NASA Astrophysics Data System (ADS)

    Lamport, Leslie

    2012-08-01

    Buridan's principle asserts that a discrete decision based upon input having a continuous range of values cannot be made within a bounded length of time. It appears to be a fundamental law of nature. Engineers aware of it can design devices so they have an infinitessimal probability of not making a decision quickly enough. Ignorance of the principle could have serious consequences.

  15. Principled Narrative

    ERIC Educational Resources Information Center

    MacBeath, John; Swaffield, Sue; Frost, David

    2009-01-01

    This article provides an overview of the "Carpe Vitam: Leadership for Learning" project, accounting for its provenance and purposes, before focusing on the principles for practice that constitute an important part of the project's legacy. These principles framed the dialogic process that was a dominant feature of the project and are presented,…

  16. Acoustic transducer

    DOEpatents

    Drumheller, D.S.

    1997-12-30

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

  17. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    1997-01-01

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

  18. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  19. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  20. 30 CFR 56.13010 - Reciprocating-type air compressors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Reciprocating-type air compressors. 56.13010... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13010 Reciprocating-type air compressors. (a) Reciprocating-type air...

  1. 27 CFR 28.23 - Reciprocating foreign countries.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Reciprocating foreign... Lading for Use on Certain Vessels and Aircraft § 28.23 Reciprocating foreign countries. The appropriate... other countries, which it is claimed reciprocate similar privileges to aircraft of the United...

  2. Familial Reciprocity and Subjective Well-Being in Ghana

    ERIC Educational Resources Information Center

    Tsai, Ming-Chang; Dzorgbo, Dan-Bright S.

    2012-01-01

    The authors investigated variations in reciprocity and the impact of reciprocity on well-being in a West African society. They hypothesized that household size and income diversity encourage reciprocity, which in turn enhances subjective well-being. In empirical testing of these hypotheses the authors used the data of the Core Welfare Indicators…

  3. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 4 2013-07-01 2013-07-01 false Reciprocal state-military action. 634.16 Section... Reciprocal state-military action. (a) Commanders will recognize the interests of the states in matters of POV... formal military reciprocity, the procedures below will be adopted: (1) Commanders will recognize...

  4. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 4 2012-07-01 2011-07-01 true Reciprocal state-military action. 634.16 Section... Reciprocal state-military action. (a) Commanders will recognize the interests of the states in matters of POV... formal military reciprocity, the procedures below will be adopted: (1) Commanders will recognize...

  5. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 4 2014-07-01 2013-07-01 true Reciprocal state-military action. 634.16 Section... Reciprocal state-military action. (a) Commanders will recognize the interests of the states in matters of POV... formal military reciprocity, the procedures below will be adopted: (1) Commanders will recognize...

  6. Norway rats reciprocate help according to the quality of help they received

    PubMed Central

    Dolivo, Vassilissa; Taborsky, Michael

    2015-01-01

    Direct reciprocity, according to the decision rule ‘help someone who has helped you before’, reflects cooperation based on the principle of postponed benefits. A predominant factor influencing Homo sapiens' motivation to reciprocate is an individ­ual's perceived benefit resulting from the value of received help. But hitherto it has been unclear whether other species also base their decision to cooperate on the quality of received help. Previous experiments have demonstrated that Norway rats, Rattus norvegicus, cooperate using direct reciprocity decision rules in a variant of the iterated Prisoner's Dilemma, where they preferentially help cooperators instead of defectors. But, as the quality of obtained benefits has not been varied, it is yet unclear whether rats use the value of received help as decision criterion to pay help back. Here, we tested whether rats distinguish between different cooperators depending purely on the quality of their help. Our data show that a rat's propensity to reciprocate help is, indeed, adjusted to the perceived quality of the partner's previous help. When cooperating with two conspecific partners expending the same effort, rats apparently rely on obtained benefit to adjust their level of returned help. PMID:25716088

  7. Norway rats reciprocate help according to the quality of help they received.

    PubMed

    Dolivo, Vassilissa; Taborsky, Michael

    2015-02-01

    Direct reciprocity, according to the decision rule 'help someone who has helped you before', reflects cooperation based on the principle of postponed benefits. A predominant factor influencing Homo sapiens' motivation to reciprocate is an individual's perceived benefit resulting from the value of received help. But hitherto it has been unclear whether other species also base their decision to cooperate on the quality of received help. Previous experiments have demonstrated that Norway rats, Rattus norvegicus, cooperate using direct reciprocity decision rules in a variant of the iterated Prisoner's Dilemma, where they preferentially help cooperators instead of defectors. But, as the quality of obtained benefits has not been varied, it is yet unclear whether rats use the value of received help as decision criterion to pay help back. Here, we tested whether rats distinguish between different cooperators depending purely on the quality of their help. Our data show that a rat's propensity to reciprocate help is, indeed, adjusted to the perceived quality of the partner's previous help. When cooperating with two conspecific partners expending the same effort, rats apparently rely on obtained benefit to adjust their level of returned help. PMID:25716088

  8. Acoustic behaviors of unsaturated soils

    NASA Astrophysics Data System (ADS)

    Lu, Z.

    2011-12-01

    Soils are unconsolidated granular materials, consisting of solid particles, water and air. Their mechanical and dynamic behaviors are determined by the discrete nature of the media as well as external and inter-particle forces. For unsaturated soils, two factors significantly affect soils acoustic/seismic responses: external pressure and internal water potential/matric suction. In triaxial cell tests, unsaturated soils were subjected to predefined stress paths to undergo stages of normal consolidation, unload-reload cycles, and failure. The stress deformation curve and stress-P-wave velocity were measured and compared. The study revealed that soil's dynamic response to external pressure are similar to those of the load-deformation behaviors and demonstrated that acoustic velocity can be used to monitor the state of stress of soils. In a long term field soil survey, the P-wave velocities were found to be correlated with water potential as expressed as a power-law relationship. The above phenomena can be understood by using the Terzaghi' s the principle of effective stress. The measured results were in good agreement with Brutsaert theory. The effective stress concept can also be applied to explain the observations in a soil pipe flow study in which soil internal erosion processes were monitored and interpreted by the temporal evolution of the P-wave velocity. In addition to above linear acoustic behaviors, soils, like other earth materials, exhibit astonishing non-classical nonlinear behaviors such as end-point memory, hysteresis, strain -dependent shear modulus, resonant frequency shift, and phase shift, harmonics generation, etc. A nonlinear acoustic study of a soil as a function of water content showed that the nonlinear acoustic parameter are much sensitive to the variations of soil water content than that of the acoustic velocity.

  9. Acoustic cryocooler

    DOEpatents

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

    1990-01-01

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

  10. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    2000-01-01

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

  11. Acoustic hemostasis

    NASA Astrophysics Data System (ADS)

    Crum, L.; Andrew, M.; Bailey, M.; Beach, K.; Brayman, A.; Curra, F.; Kaczkowski, P.; Kargl, S.; Martin, R.; Vaezy, S.

    2003-04-01

    Over the past several years, the Center for Industrial and Medical Ultrasound (CIMU) at the Applied Physics Laboratory in the University of Washington has undertaken a broad research program in the general area of High Intensity Focused Ultrasound (HIFU). Our principal emphasis has been on the use of HIFU to induce hemostasis; in particular, CIMU has sought to develop a small, lightweight, portable device that would use ultrasound for both imaging and therapy. Such a technology is needed because nearly 50% of combat casualty mortality results from exsanguinations, or uncontrolled bleeding. A similar percentage occurs for civilian death due to trauma. In this general review, a presentation of the general problem will be given, as well as our recent approaches to the development of an image-guided, transcutaneous, acoustic hemostasis device. [Work supported in part by the USAMRMC, ONR and the NIH.

  12. Acoustic telemetry.

    SciTech Connect

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

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

  13. Reciprocal capacity building for collaborative disability research between disabled people's organizations, communities and higher education institutions.

    PubMed

    Lorenzo, Theresa; Joubert, Robin

    2011-12-01

    This paper focuses on the reciprocal capacity building that occurred through collaborative research between occupational therapy departments from six higher education institutions in South Africa, community-based organizations and a disabled people's organization on disabled youth and their livelihoods. The authors aimed to identify principles for collaboration and capacity building from the pilot phase and first phase of the main study. Occupational therapy departments place students in communities for service learning experience, but little collaboration with disabled people's organizations and communities in research processes occurs that could enrich such partnerships and inform relevant curriculum development. Secondary data from different sources including a transcript of a focus-group interview with the researchers in the pilot phase, workshop reports, and transcripts of free-writing exercises done by researchers were analysed thematically, both inductively and deductively. Two themes are explored: first, reciprocal building of organizational capacity and, second, generating collaborative relationships. The principles that were identified are integral to the strengths and challenges faced when multiple organizations work together over a wide geographical area on a complex research topic that also builds capacity reciprocally. PMID:21073368

  14. Condition monitoring of reciprocating seal based on FBG sensors

    NASA Astrophysics Data System (ADS)

    Zhao, Xiuxu; Zhang, Shuanshuan; Wen, Pengfei; Zhen, Wenhan; Ke, Wei

    2016-07-01

    The failure of hydraulic reciprocating seals will seriously affect the normal operation of hydraulic reciprocating machinery, so the potential fault condition monitoring of reciprocating seals is very important. However, it is extremely difficult because of the limitation of reciprocating motion and the structure constraints of seal groove. In this study, an approach using fiber Bragg grating (FBG) sensors is presented. Experimental results show that the contact strain changes of a reciprocating seal can be detected by FBG sensors in the operation process of the hydraulic cylinders. The failure condition of the reciprocating seal can be identified by wavelet packet energy entropy, and the center frequency of power spectrum analysis. It can provide an effective solution for the fault prevention and health management of reciprocating hydraulic rod seals.

  15. Reciprocal Suffering: Caregiver Concerns During Hospice Care

    PubMed Central

    Wittenberg-Lyles, Elaine; Demiris, George; Oliver, Debra Parker; Burt, Stephanie

    2010-01-01

    Context For many hospice caregivers, the constancy and difficulty of caregiving impact their physical quality of life and cause depression, psychological distress, guilt, loneliness, and restrictions on social activities. Objectives Deviating from traditional unidimensional research on hospice caregivers, this study explored the transactional nature of reciprocal suffering by examining caregiver concerns through four dimensions: physical, psychological, social, and spiritual. Methods Researchers analyzed audiotapes of intervention discussions between hospice caregivers and research social workers. Results Results indicated that of the 125 pain talk utterances, the majority referenced psychological concern (49%), followed by physical (28%), social (22%), and spiritual (2%). Reflections on concerns revealed a global perspective of caregiving, which highlighted the patient’s needs juxtaposed to the caregiver’s recognized limitations. Conclusion By examining the reciprocal nature of suffering for caregivers, this study reinforced the need for assessing caregivers in hospice care, with specific emphasis on the importance of providing caregiver education on pain management. PMID:21146356

  16. Microelectromechanical reciprocating-tooth indexing apparatus

    SciTech Connect

    Allen, J.J..

    1999-09-28

    An indexing apparatus is disclosed that can be used to rotate a gear or move a rack in a precise, controllable manner. The indexing apparatus, based on a reciprocating shuttle driven by one or more actuators, can be formed either as a micromachine, or as a millimachine. The reciprocating shuttle of the indexing apparatus can be driven by a thermal, electrostatic or electromagnetic actuator, with one or more wedge-shaped drive teeth of the shuttle being moveable to engage and slide against indexing teeth on the gear or rack, thereby moving the gear or rack. The indexing apparatus can be formed by either surface micromachining processes or LIGA processes, depending on the size of the apparatus that is to be formed.

  17. Reciprocity in Adolescent and Caregiver Violence

    PubMed Central

    Bartle-Haring, Suzanne; Slesnick, Natasha; Carmona, Jasmin

    2014-01-01

    Over a 2-year period, with assessments every six months, the reciprocity in violent behaviors (verbal and physical) was investigated in a sample of 161 adolescents, who met the criteria for substance or alcohol abuse or dependence, and their caregivers, who participated in a clinical trial for family treatment for adolescent substance abuse. Using observed variables in a structural equation model with panel data, there was very little stability in violent behaviors across time from the perspectives of both the adolescents and caregivers. Evidence for violence reciprocity between adolescent and caregiver was demonstrated toward the end of the study period. The results are discussed in the context of previous literature about adolescent-to-parent violence. PMID:25684856

  18. Microelectromechanical reciprocating-tooth indexing apparatus

    DOEpatents

    Allen, James J.

    1999-01-01

    An indexing apparatus is disclosed that can be used to rotate a gear or move a rack in a precise, controllable manner. The indexing apparatus, based on a reciprocating shuttle driven by one or more actuators, can be formed either as a micromachine, or as a millimachine. The reciprocating shuttle of the indexing apparatus can be driven by a thermal, electrostatic or electromagnetic actuator, with one or more wedge-shaped drive teeth of the shuttle being moveable to engage and slide against indexing teeth on the gear or rack, thereby moving the gear or rack. The indexing apparatus can be formed by either surface micromachining processes or LIGA processes, depending on the size of the apparatus that is to be formed.

  19. Interdependent network reciprocity in evolutionary games

    NASA Astrophysics Data System (ADS)

    Wang, Zhen; Szolnoki, Attila; Perc, Matjaž

    2013-01-01

    Besides the structure of interactions within networks, also the interactions between networks are of the outmost importance. We therefore study the outcome of the public goods game on two interdependent networks that are connected by means of a utility function, which determines how payoffs on both networks jointly influence the success of players in each individual network. We show that an unbiased coupling allows the spontaneous emergence of interdependent network reciprocity, which is capable to maintain healthy levels of public cooperation even in extremely adverse conditions. The mechanism, however, requires simultaneous formation of correlated cooperator clusters on both networks. If this does not emerge or if the coordination process is disturbed, network reciprocity fails, resulting in the total collapse of cooperation. Network interdependence can thus be exploited effectively to promote cooperation past the limits imposed by isolated networks, but only if the coordination between the interdependent networks is not disturbed.

  20. Time Domain Modelling of a Reciprocating Engine

    NASA Astrophysics Data System (ADS)

    Li, H.; Stone, B. J.

    1999-01-01

    This paper describes the application of a time domain systems approach to the modelling of a reciprocating engine. The engine model includes the varying inertia effects resulting from the motion of the piston and con-rod. The cylinder pressure measured under operating conditions is used to force the model and the resulting motion compared with the measured response. The results obtained indicate that the model is very good.

  1. Reciprocal allopreening in the Brownheaded Nuthatch

    USGS Publications Warehouse

    Barbour, D.B.; DeGange, A.R.

    1982-01-01

    In his extensive reviews of allopreening, Harrison (1965, 1969) did not record this behavior for the Sittidae, nor did Kilham (1968, 1972, 1973) mention observing this behavior in either White-breasted (Sitta carolinensis) or Red-breasted (S. canadensis) nuthatches. Norris (1958: 187), however, mentioned the occurrence of allopreening in Brown-headed Nuthatches (S. pusilia), in passing. Here we relate our observations of reciprocal allopreening between two Brown-headed Nuthatches.

  2. Variable-Aperture Reciprocating Reed Valve

    NASA Technical Reports Server (NTRS)

    Lindner, Jeffrey L. (Inventor); Myers, W. Neill (Inventor); Kelley, Anthony R. (Inventor); Yang, Hong Q. (Inventor)

    2015-01-01

    A variable-aperture reciprocating reed valve includes a valve body defining a through hole region having a contoured-profile portion. A semi-rigid plate is affixed on one side thereof to the valve body to define a cantilever extending across the through hole region. At least one free edge of the cantilever opposes the contoured-profile portion of the through hole region in a non-contact relationship.

  3. Feasibility analysis of reciprocating magnetic heat pumps

    NASA Technical Reports Server (NTRS)

    Larson, A. V.; Hartley, J. G.; Shelton, S. V.; Smith, M. M.

    1986-01-01

    The conceptual design selected for detailed system analysis and optimization is the reciprocating gadolinium core in a regenerative fluid column within the bore of a superconducting magnet. The thermodynamic properties of gadolinium are given. A computerized literature search for relevant papers was conducted and is being analyzed. Contact was made with suppliers of superconducting magnets and accessories, magnetic materials, and various types of hardware. A description of the model for the thermal analysis of the core and regenerator fluids is included.

  4. Reciprocity between Charge Injection and Extraction and Its Influence on the Interpretation of Electroluminescence Spectra in Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Kirchartz, Thomas; Nelson, Jenny; Rau, Uwe

    2016-05-01

    Reciprocity relations based on the principle of detailed balance have been frequently used to analyze luminescence intensity and the spectrum of organic solar cells. These reciprocity relations were derived for cases where a linear extrapolation of equilibrium conditions to the nonequilibrium situations present during measurements is possible and therefore requires semiconductors with linear recombination mechanisms. Here, we discuss the impact of nonlinear recombination typically found in organic solar cells on the analysis of luminescence spectra and estimate criteria under which reciprocity relations can still be used to analyze the data. We find that depending on the exact application, only for low mobilities μ <10-4 cm2/V s or very asymmetric mobilities do substantial disagreements between simulation and analytical equations occur.

  5. Nutating spider crank reciprocating piston machine

    SciTech Connect

    Shaffer, J.E.

    1991-07-02

    This patent describes reciprocating piston apparatus. It comprises a housing; a shaft journalled on the housing for rotation about a shaft axis; a plurality of cylinders each having a central longitudinal axis and disposed parallel to the shaft axis and located on the housing at positions angularly-spaced circumferentially about the shaft; a plurality of double-acting pistons having piston axes and centers, each the piston having a transverse bore therein and being respectively mounted for reciprocation within corresponding ones of the cylinders, each the bore having a longitudinal central axis normal to the respective cylinder axis; a mutating spider having a central hub portion mounted on the shaft obliquely of the shaft axis, and having a plurality of branches extending radially outward from the hub portion and terminating at terminal ends; and means directly connecting the terminal ends centrally to corresponding ones of the bores for transferring motion between reciprocation of the pistons and rotation of the shaft, and for restraining the spider from rotating with the shaft.

  6. Compression ratio control in reciprocating piston engines

    SciTech Connect

    Doundoulakis, G.J.

    1989-08-29

    The patent describes compression ratio control for reciprocating piston engines. It comprises: a reciprocating engine crankcase; a plurality of compression/expansion cylinders rigidly attached to the crankcase; each of the cylinders including a curved surface and a cylinder head; a fuel mixture in-taken in the cylinders; a piston reciprocating along each cylinder's curved surface for providing compression/expansion to the fuel mixture; a crank mechanism including a crankshaft rotating about an axial line that is substantially equidistant from the heads, crankcheek lobes radially extending from the crankshaft, crankpins inside and in contact with crankpin bearings, axially extending between the crankcheek lobes, and crankshaft journal bearings for providing low frictional support to the crankshaft; a connecting rod for each of the cylinders connecting the piston with the crankpin; crankshaft positioning; a first transmission gear, a crankshaft gear for meshing with the transmission gear, and a slot cut on the crankcase; wherein the constraint in the displacement of the crankshaft in the horizontal sense is provided by the vertical edges of the slot, and wherein the vertical edges of the slot are preferably being curved with a radius of curvature substantially equal to the average pitch diameter of the crankshaft gear and thee first transmission gear for accurate meshing of the gears.

  7. On onsagers principle, dislocation motion and hydrogen embrittlement

    NASA Technical Reports Server (NTRS)

    Louthan, M. R., Jr.; Mcnitt, R. P.

    1976-01-01

    Onsager's reciprocal relationships from the linear theory of irreversible thermodynamics are applied to hydrogen - dislocation interactions. Existing experimental evidence shows that dislocation motion causes localized hydrogen accumulation; thus, from the Onsager principle, localized hydrogen accumulations will affect dislocation motion and therefore the properties of metals and alloys exposed to hydrogen environments.

  8. Acoustic hemostasis

    NASA Astrophysics Data System (ADS)

    Crum, Lawrence; Beach, Kirk; Carter, Stephen; Chandler, Wayne; Curra, Francesco; Kaczkowski, Peter; Keilman, George; Khokhlova, Vera; Martin, Roy; Mourad, Pierre; Vaezy, Shahram

    2000-07-01

    In cases of severe injury, physicians speak of a "golden hour"—a brief grace period in which quickly applied, proper therapy can save the life of the patient. Much of this mortality results from exsanguination, i.e., bleeding to death—often from internal hemorrhage. The inability of a paramedic to treat breaches in the vascular system deep within the body or to stem the loss of blood from internal organs is a major reason for the high level of mortality associated with blunt trauma. We have undertaken an extensive research program to treat the problem of internal bleeding. Our approach is as follows: (a) We use scanning ultrasound to identify internal bleeding and hemorrhage, (b) we use ultrasound imaging to locate specific breaches in the vascular system, both from damaged vessels and gross damage to the capillary bed, and (c) we use High Intensity Focused Ultrasound (HIFU) to treat the damaged region and to induce hemostasis. We present a general review of this research with some emphasis on the role of nonlinear acoustics.

  9. Acoustic source for generating an acoustic beam

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  10. Acoustic Holography

    NASA Astrophysics Data System (ADS)

    Kim, Yang-Hann

    One of the subtle problems that make noise control difficult for engineers is the invisibility of noise or sound. A visual image of noise often helps to determine an appropriate means for noise control. There have been many attempts to fulfill this rather challenging objective. Theoretical (or numerical) means for visualizing the sound field have been attempted, and as a result, a great deal of progress has been made. However, most of these numerical methods are not quite ready for practical applications to noise control problems. In the meantime, rapid progress with instrumentation has made it possible to use multiple microphones and fast signal-processing systems. Although these systems are not perfect, they are useful. A state-of-the-art system has recently become available, but it still has many problematic issues; for example, how can one implement the visualized noise field. The constructed noise or sound picture always consists of bias and random errors, and consequently, it is often difficult to determine the origin of the noise and the spatial distribution of the noise field. Section 26.2 of this chapter introduces a brief history, which is associated with sound visualization, acoustic source identification methods and what has been accomplished with a line or surface array. Section 26.2.3 introduces difficulties and recent studies, including de-Dopplerization and de-re verberation methods, both essential for visualizing a moving noise source, such as occurs for cars or trains. This section also addresses what produces ambiguity in realizing real sound sources in a room or closed space. Another major issue associated with sound/noise visualization is whether or not we can distinguish between mutual dependencies of noise in space (Sect. 26.2.4); for example, we are asked to answer the question, Can we see two birds singing or one bird with two beaks?

  11. Acoustic Holography

    NASA Astrophysics Data System (ADS)

    Kim, Yang-Hann

    One of the subtle problems that make noise control difficult for engineers is the invisibility of noise or sound. A visual image of noise often helps to determine an appropriate means for noise control. There have been many attempts to fulfill this rather challenging objective. Theoretical (or numerical) means for visualizing the sound field have been attempted, and as a result, a great deal of progress has been made. However, most of these numerical methods are not quite ready for practical applications to noise control problems. In the meantime, rapid progress with instrumentation has made it possible to use multiple microphones and fast signal-processing systems. Although these systems are not perfect, they are useful. A state-of-the-art system has recently become available, but it still has many problematic issues; for example, how can one implement the visualized noise field. The constructed noise or sound picture always consists of bias and random errors, and consequently, it is often difficult to determine the origin of the noise and the spatial distribution of the noise field. Section 26.2 of this chapter introduces a brief history, which is associated with "sound visualization," acoustic source identification methods and what has been accomplished with a line or surface array. Section 26.2.3 introduces difficulties and recent studies, including de-Dopplerization and de-reverberation methods, both essentialfor visualizing a moving noise source, such as occurs for cars or trains. This section also addresses what produces ambiguity in realizing real sound sources in a room or closed space. Another major issue associated with sound/noise visualization is whether or not we can distinguish between mutual dependencies of noise in space (Sect. 26.2.4); for example, we are asked to answer the question, "Can we see two birds singing or one bird with two beaks?"

  12. What Is an Acoustic Neuroma

    MedlinePlus

    ... Acoustic Neuroma An acoustic neuroma, also called a vestibular schwannoma, is a rare benign tumor of the ... Acoustic Neuroma? An acoustic neuroma, known as a vestibular schwannoma, is a benign (non-cancerous) growth that ...

  13. Canonical Acoustics and Its Application to Surface Acoustic Wave on Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shen, Jian Qi

    2016-08-01

    In a conventional formalism of acoustics, acoustic pressure p and velocity field u are used for characterizing acoustic waves propagating inside elastic/acoustic materials. We shall treat some fundamental problems relevant to acoustic wave propagation alternatively by using canonical acoustics (a more concise and compact formalism of acoustic dynamics), in which an acoustic scalar potential and an acoustic vector potential (Φ ,V), instead of the conventional acoustic field quantities such as acoustic pressure and velocity field (p,u) for characterizing acoustic waves, have been defined as the fundamental variables. The canonical formalism of the acoustic energy-momentum tensor is derived in terms of the acoustic potentials. Both the acoustic Hamiltonian density and the acoustic Lagrangian density have been defined, and based on this formulation, the acoustic wave quantization in a fluid is also developed. Such a formalism of acoustic potentials is employed to the problem of negative-mass-density assisted surface acoustic wave that is a highly localized surface bound state (an eigenstate of the acoustic wave equations). Since such a surface acoustic wave can be strongly confined to an interface between an acoustic metamaterial (e.g., fluid-solid composite structures with a negative dynamical mass density) and an ordinary material (with a positive mass density), it will give rise to an effect of acoustic field enhancement on the acoustic interface, and would have potential applications in acoustic device design for acoustic wave control.

  14. Analytical modelling of acoustic emission from buried or surface-breaking cracks under stress

    NASA Astrophysics Data System (ADS)

    Ben Khalifa, W.; Jezzine, K.; Hello, G.; Grondel, S.

    2012-03-01

    Acoustic emission (AE) is a non-destructive testing method used in various industries (aerospace, petrochemical and pressure-vessel industries in general, power generation, civil engineering, mechanical engineering, etc...) for the examination of large structures subjected to various stresses (e.g. mechanical loading).The energy released by a defect under stress (the AE phenomenon) can propagate as guided waves in thin structures or as surface Rayleigh waves in thick ones. Sensors (possibly permanently) are positioned at various locations on the structure under examination and are assumed to be sensitive to these waves. Then, post-processing tools typically based on signal processing and triangulation algorithms can be used to inverse these data, allowing one to estimate the position of the defect from which emanates the waves measured. The French Atomic Energy Commission is engaged in the development of tools for simulating AE examinations. These tools are based on specific models for the AE sources, for the propagation of guided or Rayleigh waves and for the behaviour of AE sensors. Here, the coupling of a fracture mechanics based model for AE source and surface/guided wave propagation models is achieved through an integral formulation relying on the elastodynamic reciprocity principle. As a first approximation, a simple piston-like model is used to predict the sensitivity of AE sensors. Predictions computed by our simulation tool are compared to results from the literature for validation purpose.

  15. Neural correlate of human reciprocity in social interactions

    PubMed Central

    Sakaiya, Shiro; Shiraito, Yuki; Kato, Junko; Ide, Hiroko; Okada, Kensuke; Takano, Kouji; Kansaku, Kenji

    2013-01-01

    Reciprocity plays a key role maintaining cooperation in society. However, little is known about the neural process that underpins human reciprocity during social interactions. Our neuroimaging study manipulated partner identity (computer, human) and strategy (random, tit-for-tat) in repeated prisoner's dilemma games and investigated the neural correlate of reciprocal interaction with humans. Reciprocal cooperation with humans but exploitation of computers by defection was associated with activation in the left amygdala. Amygdala activation was also positively and negatively correlated with a preference change for human partners following tit-for-tat and random strategies, respectively. The correlated activation represented the intensity of positive feeling toward reciprocal and negative feeling toward non-reciprocal partners, and so reflected reciprocity in social interaction. Reciprocity in social interaction, however, might plausibly be misinterpreted and so we also examined the neural coding of insight into the reciprocity of partners. Those with and without insight revealed differential brain activation across the reward-related circuitry (i.e., the right middle dorsolateral prefrontal cortex and dorsal caudate) and theory of mind (ToM) regions [i.e., ventromedial prefrontal cortex (VMPFC) and precuneus]. Among differential activations, activation in the precuneus, which accompanied deactivation of the VMPFC, was specific to those without insight into human partners who were engaged in a tit-for-tat strategy. This asymmetric (de)activation might involve specific contributions of ToM regions to the human search for reciprocity. Consequently, the intensity of emotion attached to human reciprocity was represented in the amygdala, whereas insight into the reciprocity of others was reflected in activation across the reward-related and ToM regions. This suggests the critical role of mentalizing, which was not equated with reward expectation during social interactions

  16. Symptoms of Acoustic Neuroma

    MedlinePlus

    ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...

  17. Reciprocal invisibility cloak based on complementary media

    NASA Astrophysics Data System (ADS)

    Yang, J. J.; Huang, M.; Yang, C. F.; Yu, J.

    2011-02-01

    The first invisibility cloak was proposed by Pendry et al. [Science 312, 1780 (2006)]. But the object enclosed in this original cloak is "blind", that is, it cannot see the outside world, since no electromagnetic waves can reach within the cloaked space. Based on the concept of complementary media, we propose a reciprocal invisibility cloak, in which the hidden object can see the outside world, but its presence cannot be detected by electromagnetic wave. The performance of the cloak has been verified by full-wave simulations.

  18. Designing topological bands in reciprocal space.

    PubMed

    Cooper, N R; Moessner, R

    2012-11-21

    Motivated by new capabilities to realize artificial gauge fields in ultracold atomic systems, and by their potential to access correlated topological phases in lattice systems, we present a new strategy for designing topologically nontrivial band structures. Our approach is simple and direct: it amounts to considering tight-binding models directly in reciprocal space. These models naturally cause atoms to experience highly uniform magnetic flux density and lead to topological bands with very narrow dispersion, without fine-tuning of parameters. Further, our construction immediately yields instances of optical Chern lattices, as well as band structures with Chern numbers of magnitude larger than one. PMID:23215598

  19. Principles of thermoacoustic energy harvesting

    NASA Astrophysics Data System (ADS)

    Avent, A. W.; Bowen, C. R.

    2015-11-01

    Thermoacoustics exploit a temperature gradient to produce powerful acoustic pressure waves. The technology has a key role to play in energy harvesting systems. A time-line in the development of thermoacoustics is presented from its earliest recorded example in glass blowing through to the development of the Sondhauss and Rijke tubes to Stirling engines and pulse-tube cryo-cooling. The review sets the current literature in context, identifies key publications and promising areas of research. The fundamental principles of thermoacoustic phenomena are explained; design challenges and factors influencing efficiency are explored. Thermoacoustic processes involve complex multi-physical coupling and transient, highly non-linear relationships which are computationally expensive to model; appropriate numerical modelling techniques and options for analyses are presented. Potential methods of harvesting the energy in the acoustic waves are also examined.

  20. Reciprocating magnetic refrigerator employing tandem porous matrices within a reciprocating displacer

    NASA Technical Reports Server (NTRS)

    Johnson, D. L. (Inventor)

    1985-01-01

    Disclosed is a method and apparatus for a magnetic refrigeration system. A continuously reciprocating displacer houses at least a pair of paramagnetic substances each of which is alternately driven into and out of a magnetic field. Two separate bidirectional pumping systems flow helium gas through the displacer and through both paramagnetic substances to create heat exchange conditions at two separate temperature extremes.

  1. Acoustic emission frequency discrimination

    NASA Technical Reports Server (NTRS)

    Sugg, Frank E. (Inventor); Graham, Lloyd J. (Inventor)

    1988-01-01

    In acoustic emission nondestructive testing, broadband frequency noise is distinguished from narrow banded acoustic emission signals, since the latter are valid events indicative of structural flaws in the material being examined. This is accomplished by separating out those signals which contain frequency components both within and beyond (either above or below) the range of valid acoustic emission events. Application to acoustic emission monitoring during nondestructive bond verification and proof loading of undensified tiles on the Space Shuttle Orbiter is considered.

  2. Institutionalize Reciprocity to Overcome the Public Goods Provision Problem

    PubMed Central

    2016-01-01

    Cooperation is fundamental to human societies, and one of the important paths for its emergence and maintenance is reciprocity. In prisoner’s dilemma (PD) experiments, reciprocal strategies are often effective at attaining and maintaining high cooperation. In many public goods (PG) games or n-person PD experiments, however, reciprocal strategies are not successful at engendering cooperation. In the present paper, we attribute this difficulty to a coordination problem against free riding among reciprocators: Because it is difficult for the reciprocators to coordinate their behaviors against free riders, this may lead to inequality among players, which will demotivate them from cooperating in future rounds. We propose a new mechanism, institutionalized reciprocity (IR), which refers to embedding the reciprocal strategy as an institution (i.e., institutionalizing the reciprocal strategy). We experimentally demonstrate that IR can prevent groups of reciprocators from falling into coordination failure and achieve high cooperation in PG games. In conclusion, we argue that a natural extension of the present study will be to investigate the possibility of IR to serve as a collective punishment system. PMID:27248493

  3. Institutionalize Reciprocity to Overcome the Public Goods Provision Problem.

    PubMed

    Ozono, Hiroki; Kamijo, Yoshio; Shimizu, Kazumi

    2016-01-01

    Cooperation is fundamental to human societies, and one of the important paths for its emergence and maintenance is reciprocity. In prisoner's dilemma (PD) experiments, reciprocal strategies are often effective at attaining and maintaining high cooperation. In many public goods (PG) games or n-person PD experiments, however, reciprocal strategies are not successful at engendering cooperation. In the present paper, we attribute this difficulty to a coordination problem against free riding among reciprocators: Because it is difficult for the reciprocators to coordinate their behaviors against free riders, this may lead to inequality among players, which will demotivate them from cooperating in future rounds. We propose a new mechanism, institutionalized reciprocity (IR), which refers to embedding the reciprocal strategy as an institution (i.e., institutionalizing the reciprocal strategy). We experimentally demonstrate that IR can prevent groups of reciprocators from falling into coordination failure and achieve high cooperation in PG games. In conclusion, we argue that a natural extension of the present study will be to investigate the possibility of IR to serve as a collective punishment system. PMID:27248493

  4. Broad-band acoustic Doppler current profiler

    USGS Publications Warehouse

    Cobb, E.D.

    1993-01-01

    The broad-band acoustic Doppler current profiler is an instrument that determines velocity based on the Doppler principle by reflecting acoustic signals off sediment particles in the water. The instrument is capable of measuring velocity magnitude and direction throughout a water column and of measuring water depth. It is also capable of bottom tracking and can, therefore, keep track of its own relative position as it is moved across a channel. Discharge measurements can be made quickly and, based on limited tests, accurately with this instrument. ?? 1993.

  5. Design of a programmable active acoustics metamaterial

    NASA Astrophysics Data System (ADS)

    Smoker, Jason J.

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

  6. Dynamic Reciprocity Between Cells and Their Microenvironment in Reproduction1

    PubMed Central

    Thorne, Jeffrey T.; Segal, Thalia R.; Chang, Sydney; Jorge, Soledad; Segars, James H.; Leppert, Phyllis C.

    2014-01-01

    ABSTRACT Dynamic reciprocity (DR) refers to the ongoing, bidirectional interaction between cells and their microenvironment, specifically the extracellular matrix (ECM). The continuous remodeling of the ECM exerts mechanical force on cells and modifies biochemical mediators near the cell membrane, thereby initiating cell-signaling cascades that produce changes in gene expression and cell behavior. Cellular changes, in turn, affect the composition and organization of ECM components. These continuous interactions are the fundamental principle behind DR, and its critical role throughout development and adult tissue homeostasis has been extensively investigated. While DR in the mammary gland has been well described, we provide direct evidence that similar dynamic interactions occur in other areas of reproductive biology as well. In order to establish the importance of DR in the adaptive functioning of the female reproductive tract, we present our most current understanding of DR in reproductive tissues, exploring the mammary gland, ovary, and uterus. In addition to explaining normal physiological function, investigating DR may shed new light into pathologic processes that occur in these tissues and provide an exciting opportunity for novel therapeutic intervention. PMID:25411389

  7. Tutorial on architectural acoustics

    NASA Astrophysics Data System (ADS)

    Shaw, Neil; Talaske, Rick; Bistafa, Sylvio

    2002-11-01

    This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).

  8. Acoustic competition in the gulf toadfish Opsanus beta: Acoustic tagging

    NASA Astrophysics Data System (ADS)

    Thorson, Robert F.; Fine, Michael L.

    2002-05-01

    Nesting male gulf toadfish Opsanus beta produce a boatwhistle advertisement call used in male-male competition and to attract females and an agonistic grunt call. The grunt is a short-duration pulsatile call, and the boatwhistle is a complex call typically consisting of zero to three introductory grunts, a long tonal boop note, and zero to three shorter boops. The beginning of the boop note is also gruntlike. Anomalous boatwhistles contain a short-duration grunt embedded in the tonal portion of the boop or between an introductory grunt and the boop. Embedded grunts have sound-pressure levels and frequency spectra that correspond with those of recognized neighbors, suggesting that one fish is grunting during another's call, a phenomenon here termed acoustic tagging. Snaps of nearby pistol shrimp may also be tagged, and chains of tags involving more than two fish occur. The stimulus to tag is a relatively intense sound with a rapid rise time, and tags are generally produced within 100 ms of a trigger stimulus. Time between the trigger and the tag decreases with increased trigger amplitude. Tagging is distinct from increased calling in response to natural calls or stimulatory playbacks since calls rarely overlap other calls or playbacks. Tagging is not generally reciprocal between fish, suggesting parallels to dominance displays.

  9. Laser Acoustic Imaging of Film Bulk Acoustic Resonator (FBAR) Lateral Mode Dispersion

    SciTech Connect

    Ken L. Telschow

    2004-07-01

    A laser acoustic imaging microscope has been developed that measures acoustic motion with high spatial resolution without scanning. Images are recorded at normal video frame rates and heterodyne principles are used to allow operation at any frequency from Hz to GHz. Fourier transformation of the acoustic amplitude and phase displacement images provides a direct quantitative determination of excited mode wavenumbers at any frequency. Results are presented at frequencies near the first longitudinal thickness mode (~ 900 MHz) demonstrating simultaneous excitation of lateral modes with nonzero wavenumbers in an electrically driven AlN thin film acoustic resonator. Images combined at several frequencies form a direct visualization of lateral mode dispersion relations for the device under test allowing mode identification and a direct measure of specific lateral mode properties. Discussion and analysis of the results are presented in comparison with plate wave modeling of these devices taking account for material anisotropy and multilayer films.

  10. Reciprocating piston pump system with screw drive

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor); Moore, Nicholas R. (Inventor)

    1981-01-01

    A pump system of the reciprocating piston type is described, which facilitates direct motor drive and cylinder sealing. A threaded middle potion of the piston is engaged by a nut connected to rotate with the rotor of an electric motor, in a manner that minimizes loading on the rotor by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded piston portion, with an oil-carrying groove in the nut being interrupted. A fluid emitting seal located at the entrance to each cylinder, can serve to center the piston within the cylinder, wash the piston, and to aid in sealing. The piston can have a long stroke to diameter ratio to minimize reciprocations and wear on valves at high pressures. The voltage applied to the motor can be reversed prior to the piston reaching the end of its stroke, to permit pressure on the piston to aid in reversing the motor.

  11. Dynamic Reciprocity in Cell-Scaffold Interactions

    PubMed Central

    Mauney, Joshua R.; Adam, Rosalyn M.

    2014-01-01

    Tissue engineering in urology has shown considerable promise. However, there is still much to understand, particularly regarding the interactions between scaffolds and their host environment, how these interactions regulate regeneration and how they may be enhanced for optimal tissue repair. In this review, we discuss the concept of dynamic reciprocity as applied to tissue engineering, i.e. how bi-directional signaling between implanted scaffolds and host tissues such as the bladder drives the process of constructive remodeling to ensure successful graft integration and tissue repair. The impact of scaffold content and configuration, the contribution of endogenous and exogenous bioactive factors, the influence of the host immune response and the functional interaction with mechanical stimulation are all considered. In addition, the temporal relationships of host tissue ingrowth, bioactive factor mobilization, scaffold degradation and immune cell infiltration, as well as the reciprocal signaling between discrete cell types and scaffolds are discussed. Improved understanding of these aspects of tissue repair will identify opportunities for optimization of repair that could be exploited to enhance regenerative medicine strategies for urology in future studies. PMID:25453262

  12. Using Excel's Matrix Operations to Facilitate Reciprocal Cost Allocations

    ERIC Educational Resources Information Center

    Leese, Wallace R.; Kizirian, Tim

    2009-01-01

    The reciprocal method of service department cost allocation requires linear equations to be solved simultaneously. These computations are often so complex as to cause the abandonment of the reciprocal method in favor of the less sophisticated direct or step-down methods. Here is a short example demonstrating how Excel's sometimes unknown matrix…

  13. Reciprocal Borrowing Patterns in the North Suburban Library System.

    ERIC Educational Resources Information Center

    Able Consultants, DeKalb, IL.

    During a 5-day period in 1990, a total of 1,401 reciprocal borrowers in the North Suburban Library System (NSLS) received questionnaires asking about their choice of library and other aspects of borrowing behavior to provide data on the reciprocal borrowing characteristics and patterns within the system. This survey was designed to identify the…

  14. 2005 Reciprocity Agreements and Other Student Exchange Options

    ERIC Educational Resources Information Center

    Washington Higher Education Coordinating Board, 2005

    2005-01-01

    The Higher Education Coordinating Board (HECB) is required by state law to report to the governor and legislature every two years on the status of Washington's state-level reciprocity agreements with Idaho, Oregon, and British Columbia. Reciprocity agreements allow some Washington students to attend public colleges in other states and pay lower…

  15. Accepting Roles Created for Us: The Ethics of Reciprocity.

    ERIC Educational Resources Information Center

    Powell, Katrina M.; Takayoshi, Pamela

    2003-01-01

    Argues that seeing reciprocity as a context-based process of definition and re-definition of the relationship between participants and researchers helps them understand how research projects can benefit participants in ways that they desire. Considers the ethical dimensions of reciprocal research relationships. Uses the authors' own research…

  16. 47 CFR 51.711 - Symmetrical reciprocal compensation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Symmetrical reciprocal compensation. 51.711 Section 51.711 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... Traffic § 51.711 Symmetrical reciprocal compensation. (a) Rates for transport and termination of...

  17. Symmetry-based reciprocity: evolutionary constraints on a proximate mechanism

    PubMed Central

    Campennì, Marco

    2016-01-01

    Background. While the evolution of reciprocal cooperation has attracted an enormous attention, the proximate mechanisms underlying the ability of animals to cooperate reciprocally are comparatively neglected. Symmetry-based reciprocity is a hypothetical proximate mechanism that has been suggested to be widespread among cognitively unsophisticated animals. Methods. We developed two agent-based models of symmetry-based reciprocity (one relying on an arbitrary tag and the other on interindividual proximity) and tested their ability both to reproduce significant emergent features of cooperation in group living animals and to promote the evolution of cooperation. Results. Populations formed by agents adopting symmetry-based reciprocity showed differentiated “social relationships” and a positive correlation between cooperation given and received: two common aspects of animal cooperation. However, when reproduction and selection across multiple generations were added to the models, agents adopting symmetry-based reciprocity were outcompeted by selfish agents that never cooperated. Discussion. In order to evolve, hypothetical proximate mechanisms must be able to stand competition from alternative strategies. While the results of our simulations require confirmation using analytical methods, we provisionally suggest symmetry-based reciprocity is to be abandoned as a possible proximate mechanism underlying the ability of animals to reciprocate cooperative interactions. PMID:26998412

  18. Reciprocal Relationships between Math Self-Concept and Math Anxiety

    ERIC Educational Resources Information Center

    Ahmed, Wondimu; Minnaert, Alexander; Kuyper, Hans; van der Werf, Greetje

    2012-01-01

    The present study examined the reciprocal relationships between self-concept and anxiety in mathematics. A sample of 495 grade 7 students (51% girls) completed self-report measures assessing self-concept and anxiety three times in a school year. Structural equation modeling was used to test a cross-lagged panel model of reciprocal effects between…

  19. An Analysis of Direct Reciprocal Borrowing among Quebec University Libraries

    ERIC Educational Resources Information Center

    Duy, Joanna C.; Lariviere, Vincent

    2013-01-01

    An analysis of Quebec academic libraries' direct reciprocal borrowing statistics from 2005 to 2010 reveals that the physical distance separating universities plays an important role in determining the amount of direct reciprocal borrowing activity conducted between institutions. Significant statistical correlations were also seen between the…

  20. Transient nature of cooperation by pay-it-forward reciprocity

    PubMed Central

    Horita, Yutaka; Takezawa, Masanori; Kinjo, Takuji; Nakawake, Yo; Masuda, Naoki

    2016-01-01

    Humans often forward kindness received from others to strangers, a phenomenon called the upstream or pay-it-forward indirect reciprocity. Some field observations and laboratory experiments found evidence of pay-it-forward reciprocity in which chains of cooperative acts persist in social dilemma situations. Theoretically, however, cooperation based on pay-it-forward reciprocity is not sustainable. We carried out laboratory experiments of a pay-it-forward indirect reciprocity game (i.e., chained gift-giving game) on a large scale in terms of group size and time. We found that cooperation consistent with pay-it-forward reciprocity occurred only in a first few decisions per participant and that cooperation originated from inherent pro-sociality of individuals. In contrast, the same groups of participants showed persisting chains of cooperation in a different indirect reciprocity game in which participants earned reputation by cooperating. Our experimental results suggest that pay-it-forward reciprocity is transient and disappears when a person makes decisions repeatedly, whereas the reputation-based reciprocity is stable in the same situation. PMID:26786178

  1. Instructional Guidance in Reciprocal Peer Tutoring With Task Cards

    ERIC Educational Resources Information Center

    Iserbyt, Peter; Elen, Jan; Behets, Daniel

    2010-01-01

    This article addresses the issue of instructional guidance in reciprocal peer tutoring with task cards as learning tools. Eighty-six Kinesiology students (age 17-19 years) were randomized across four reciprocal peer tutoring settings, differing in quality and quantity of guidance, to learn Basic Life Support (BLS) with task cards. The separate and…

  2. Similarity and Reciprocity in the Friendships of Elementary School Children.

    ERIC Educational Resources Information Center

    Clark, M. L.; Drewry, Debra L.

    1985-01-01

    Investigated the effect of similarity and reciprocity on dyadic friendship choices in third- and sixth-grade students. Reciprocal (mutual) friendships were more similar in proximity, popularity, and self-concept than those in nonreciprocal (nonmutual) dyads. Results are discussed in relation to the interpersonal attraction theories. (Author/DST)

  3. “It's Not What You Say, But How You Say it”: A Reciprocal Temporo-frontal Network for Affective Prosody

    PubMed Central

    Leitman, David I.; Wolf, Daniel H.; Ragland, J. Daniel; Laukka, Petri; Loughead, James; Valdez, Jeffrey N.; Javitt, Daniel C.; Turetsky, Bruce I.; Gur, Ruben C.

    2009-01-01

    Humans communicate emotion vocally by modulating acoustic cues such as pitch, intensity and voice quality. Research has documented how the relative presence or absence of such cues alters the likelihood of perceiving an emotion, but the neural underpinnings of acoustic cue-dependent emotion perception remain obscure. Using functional magnetic resonance imaging in 20 subjects we examined a reciprocal circuit consisting of superior temporal cortex, amygdala and inferior frontal gyrus that may underlie affective prosodic comprehension. Results showed that increased saliency of emotion-specific acoustic cues was associated with increased activation in superior temporal cortex [planum temporale (PT), posterior superior temporal gyrus (pSTG), and posterior superior middle gyrus (pMTG)] and amygdala, whereas decreased saliency of acoustic cues was associated with increased inferior frontal activity and temporo-frontal connectivity. These results suggest that sensory-integrative processing is facilitated when the acoustic signal is rich in affective information, yielding increased activation in temporal cortex and amygdala. Conversely, when the acoustic signal is ambiguous, greater evaluative processes are recruited, increasing activation in inferior frontal gyrus (IFG) and IFG STG connectivity. Auditory regions may thus integrate acoustic information with amygdala input to form emotion-specific representations, which are evaluated within inferior frontal regions. PMID:20204074

  4. Reciprocal and unidirectional scattering of parity-time symmetric structures

    PubMed Central

    Jin, L.; Zhang, X. Z.; Zhang, G.; Song, Z.

    2016-01-01

    Parity-time symmetry is of great interest. The reciprocal and unidirectional features are intriguing besides the symmetry phase transition. Recently, the reciprocal transmission, unidirectional reflectionless and invisibility are intensively studied. Here, we show the reciprocal reflection/transmission in -symmetric system is closely related to the type of symmetry, that is, the axial (reflection) symmetry leads to reciprocal reflection (transmission). The results are further elucidated by studying the scattering of rhombic ring form coupled resonators with enclosed synthetic magnetic flux. The nonreciprocal phase shift induced by the magnetic flux and gain/loss break the parity and time-reversal symmetry but keep the parity-time symmetry. The reciprocal reflection (transmission) and unidirectional transmission (reflection) are found in the axial (reflection) -symmetric ring centre. The explorations of symmetry and asymmetry from symmetry may shed light on novel one-way optical devices and application of -symmetric metamaterials. PMID:26876806

  5. Rethinking natural altruism: simple reciprocal interactions trigger children's benevolence.

    PubMed

    Cortes Barragan, Rodolfo; Dweck, Carol S

    2014-12-01

    A very simple reciprocal activity elicited high degrees of altruism in 1- and 2-y-old children, whereas friendly but nonreciprocal activity yielded little subsequent altruism. In a second study, reciprocity with one adult led 1- and 2-y-olds to provide help to a new person. These results question the current dominant claim that social experiences cannot account for early occurring altruistic behavior. A third study, with preschool-age children, showed that subtle reciprocal cues remain potent elicitors of altruism, whereas a fourth study with preschoolers showed that even a brief reciprocal experience fostered children's expectation of altruism from others. Collectively, the studies suggest that simple reciprocal interactions are a potent trigger of altruism for young children, and that these interactions lead children to believe that their relationships are characterized by mutual care and commitment. PMID:25404334

  6. Does food sharing in vampire bats demonstrate reciprocity?

    PubMed

    Carter, Gerald; Wilkinson, Gerald

    2013-11-01

    Claims of reciprocity (or reciprocal altruism) in animal societies often ignite controversy because authors disagree over definitions, naturalistic studies tend to demonstrate correlation not causation, and controlled experiments often involve artificial conditions. Food sharing among common vampire bats has been a classic textbook example of reciprocity, but this conclusion has been contested by alternative explanations. Here, we review factors that predict food sharing in vampire bats based on previously published and unpublished data, validate previous published results with more precise relatedness estimates, and describe current evidence for and against alternative explanations for its evolutionary stability. Although correlational evidence indicates a role for both direct and indirect fitness benefits, unequivocally demonstrating reciprocity in vampire bats still requires testing if and how bats respond to non-reciprocation. PMID:24505498

  7. Quantitative genetically nonequivalent reciprocal crosses in cultivated plants.

    PubMed

    Aksel, R

    Quantitative expressions of character difference between reciprocal crosses have been studied by different researchers in a number of plant species, such as Epilobium, Zea mays, Oryza sativa, Hordeum sativum, Triticum aestivum, Trifolium hybridum, Linum usitatissimum, Nicotiana rustica, and others. In all cases it was found that the nonequivalence of reciprocal crosses manifested itself beginning with the F1 generation, with the exception of some flax crosses in which reciprocals differed beginning with the F2 generation. The nonequivalence of reciprocal crosses usually manifested itself in the inequality of their F1 and/or F2 or backcross means; however, there were instances in which their means were the same but the variances were different. Both matroclinous and patroclinous inheritances were reported in plants. Because of the casual complexity of reciprocal differences the experimental results often lack a simple explanation. PMID:1032105

  8. Numerical analysis of flows in reciprocating engines

    NASA Astrophysics Data System (ADS)

    Takata, H.; Kojima, M.

    1986-07-01

    A numerical method of the analysis for three-dimensional turbulent flow in cylinders of reciprocating engines with arbitrary geometry is described. A scheme of the finite volume/finite element methods is used, employing a large number of small elements of arbitrary shapes to form a cylinder. The fluid dynamic equations are expressed in integral form for each element, taking into account the deformation of the element shape according to the piston movements, and are solved in the physical space using rectangular coordinates. The conventional k-epsilon two-equation model is employed to describe the flow turbulence. Example calculations are presented for simple pancake-type combustion chambers having an annular intake port at either center or asymmetric position of the cylinder head. The suction inflow direction is also changed in several ways. The results show a good simulation of overall fluid movements within the engine cylinder.

  9. Sleep and exercise: a reciprocal issue?

    PubMed

    Chennaoui, Mounir; Arnal, Pierrick J; Sauvet, Fabien; Léger, Damien

    2015-04-01

    Sleep and exercise influence each other through complex, bilateral interactions that involve multiple physiological and psychological pathways. Physical activity is usually considered as beneficial in aiding sleep although this link may be subject to multiple moderating factors such as sex, age, fitness level, sleep quality and the characteristics of the exercise (intensity, duration, time of day, environment). It is therefore vital to improve knowledge in fundamental physiology in order to understand the benefits of exercise on the quantity and quality of sleep in healthy subjects and patients. Conversely, sleep disturbances could also impair a person's cognitive performance or their capacity for exercise and increase the risk of exercise-induced injuries either during extreme and/or prolonged exercise or during team sports. This review aims to describe the reciprocal fundamental physiological effects linking sleep and exercise in order to improve the pertinent use of exercise in sleep medicine and prevent sleep disorders in sportsmen. PMID:25127157

  10. Balancing mechanism for reciprocating piston engine

    SciTech Connect

    Murata, N.; Ogino, T.

    1987-04-14

    This patent describes a balancing mechanism for a reciprocating piston internal combustion engine which includes a cylinder, a piston reciprocatable in the cylinder, a crankcase, a crankshaft mounted in the crankshaft, a crankpin connected to the piston, and a pair of crank arms bridging the crankshaft and crankpin. The crank arms and crankpin rotate with the crankshaft during operation and form a rotating mass. The balancing mechanism comprises at least one rotating counterweight attached to and rotating with the crankshaft, and eccentric journal means on the crankshaft adjacent the crank arms, rotating with the crankshaft. The journal means has an axis spaced to the side of the crankshaft axis which is opposite from the crankpin. The rotating counterweight and the eccentric journal means counterbalancing the rotating mass.

  11. Thermal Powered Reciprocating-Force Motor

    NASA Technical Reports Server (NTRS)

    Tatum, III, Paul F. (Inventor); McDow Elliott, Amelia (Inventor)

    2015-01-01

    A thermal-powered reciprocating-force motor includes a shutter switchable between a first position that passes solar energy and a second position that blocks solar energy. A shape memory alloy (SMA) actuator is coupled to the shutter to control switching thereof between the shutter's first and second position. The actuator is positioned with respect to the shutter such that (1) solar energy impinges on the SMA when the shutter is in its first position so that the SMA experiences contraction in length until the shutter is switched to its second position, and (2) solar energy is impeded from impingement on the SMA when the shutter is in its second position so that the SMA experiences extension in length. Elastic members coupled to the actuator apply a force to the SMA that aids in its extension in length until the shutter is switched to its first position.

  12. An experimental reciprocating expander for cryocooler application

    NASA Technical Reports Server (NTRS)

    Minta, M.; Smith, J. L., Jr.

    1985-01-01

    An experimental reciprocating expander was designed with features appropriate for cryocooler cycles. The expander has a displacer piston, simple valves, and a hydraulic/pneumatic stroking mechanism. The expander has a valve in head configuration with the valves extending out the bottom of the vacuum enclosure while the piston extends out the top. The expander was tested using a CTI 1400 liquefier to supply 13 atm in the temperature range 4.2 to 12 K. Expander efficiency was measured in the range 84 to 93% while operating the apparatus as a supercritical wet expander and in the range 91 to 93% aa a single phase expander. The apparatus can also be modified to operate as a compressor for saturated helium vapor.

  13. Linkage map construction involving a reciprocal translocation.

    PubMed

    Farré, A; Benito, I Lacasa; Cistué, L; de Jong, J H; Romagosa, I; Jansen, J

    2011-03-01

    This paper is concerned with a novel statistical-genetic approach for the construction of linkage maps in populations obtained from reciprocal translocation heterozygotes of barley (Hordeum vulgare L.). Using standard linkage analysis, translocations usually lead to 'pseudo-linkage': the mixing up of markers from the chromosomes involved in the translocation into a single linkage group. Close to the translocation breakpoints recombination is severely suppressed and, as a consequence, ordering markers in those regions is not feasible. The novel strategy presented in this paper is based on (1) disentangling the "pseudo-linkage" using principal coordinate analysis, (2) separating individuals into translocated types and normal types and (3) separating markers into those close to and those more distant from the translocation breakpoints. The methods make use of a consensus map of the species involved. The final product consists of integrated linkage maps of the distal parts of the chromosomes involved in the translocation. PMID:21153624

  14. Reciprocal relativity of noninertial frames: quantum mechanics

    NASA Astrophysics Data System (ADS)

    Low, Stephen G.

    2007-04-01

    Noninertial transformations on time-position-momentum-energy space {t, q, p, e} with invariant Born-Green metric ds^{2}=-d t^{2}+\\frac{1}{c^{2}}\\,d q^{2}+\\frac{1}{b^{2}} \\big(d p^{2}-\\frac{1}{c^{2}}\\,d e^{2}\\big) and the symplectic metric -de ∧ dt + dp ∧ dq are studied. This {\\cal U}1,3) group of transformations contains the Lorentz group as the inertial special case and, in the limit of small forces and velocities, reduces to the expected Hamilton transformations leaving invariant the symplectic metric and the nonrelativistic line element ds2 = -dt2. The {\\cal U}( 1,3) transformations bound relative velocities by c and relative forces by b. Spacetime is no longer an invariant subspace but is relative to noninertial observer frames. In the limit of b → ∞, spacetime is invariant. Born was lead to the metric by a concept of reciprocity between position and momentum degrees of freedom and for this reason we call this reciprocal relativity. For large b, such effects will almost certainly only manifest in a quantum regime. Wigner showed that special relativistic quantum mechanics follows from the projective representations of the inhomogeneous Lorentz group. Projective representations of a Lie group are equivalent to the unitary representations of its central extension. The same method of projective representations for the inhomogeneous {\\cal U}( 1,3) group is used to define the quantum theory in the noninertial case. The central extension of the inhomogeneous {\\cal U}( 1,3) group is the cover of the quaplectic group {\\cal Q}( 1,3) ={\\cal U}( 1,3) \\otimes _{s}{\\cal H}(4) . {\\cal H}( 4) is the Weyl-Heisenberg group. The {\\cal H}( 4) group, and the associated Heisenberg commutation relations central to quantum mechanics, results directly from requiring projective representations. A set of second-order wave equations result from the representations of the Casimir operators.

  15. The effect of local dominance and reciprocal tolerance on feeding aggregations of ocellated antbirds.

    PubMed

    Chaves-Campos, Johel; Araya-Ajoy, Yi-Men; Lizana-Moreno, Claudia A; Rabenold, Kerry N

    2009-11-22

    We studied ocellated antbirds (Phaenostictus mcleannani) to test the hypothesis that reciprocal tolerance between dominant individuals can favour feeding in aggregations. Mated pairs hold large non-exclusive feeding ranges, but roost and nest in a small portion of this range ('roosting area'); adjacent roosting neighbours are unrelated. Ocellated antbirds congregate to feed on arthropods fleeing from nomadic swarms of army ants that move across the ranges of many pairs. We used playback experiments to simulate acoustic challenges, and results showed that males responded aggressively to other males only in their roosting areas. Responses to adjacent neighbours were less aggressive than to non-neighbours (i.e. the 'dear enemy' effect). Prey intake rates were higher when birds fed in their own roosting area or in that of adjacent neighbours compared with more distant sites. Males tolerated adjacent neighbours at swarm fronts where prey are most dense, but more distant neighbours were displaced. Despite small samples for some analyses, our results suggest that reciprocal tolerance between adjacent unrelated neighbours can ameliorate intraspecific competition within ephemeral feeding aggregations. PMID:19710061

  16. Onsager’s reciprocal relations in electrolyte solutions. I. Sedimentation and electroacoustics

    SciTech Connect

    Gourdin-Bertin, S.; Bernard, O.; Jardat, M.; Chassagne, C.

    2015-08-14

    In the framework of irreversible thermodynamics, we show that the sedimentation current in electrolyte solutions is mathematically equivalent to the low frequency limit of the ionic vibration current, appearing in the presence of an acoustic wave. This non-trivial result is obtained thanks to a careful choice of the reference frame used to express the mass fluxes in the context of electroacoustics. Coupled transport phenomena in electrolyte solutions can also be investigated in a mechanical framework, with a set of Newtonian equations for the dynamics of charged solutes. Both in the context of sedimentation and of electroacoustics, we show that the results obtained in the mechanical framework, in the ideal case (i.e., without interactions between ions), do satisfy the Onsager’s reciprocal relations. We also derive the general relation between corrective forces accounting for ionic interactions which must be fulfilled so that the Onsager’s reciprocal relations are verified. Finally, we show that no additional diffusion term needs to be taken into account in the flux of solutes (far from the walls), even if local concentration gradients exist, contrarily to what was done previously in the literature.

  17. AST Launch Vehicle Acoustics

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  18. Generalized uncertainty principle: Approaches and applications

    NASA Astrophysics Data System (ADS)

    Tawfik, A.; Diab, A.

    2014-11-01

    In this paper, we review some highlights from the String theory, the black hole physics and the doubly special relativity and some thought experiments which were suggested to probe the shortest distances and/or maximum momentum at the Planck scale. Furthermore, all models developed in order to implement the minimal length scale and/or the maximum momentum in different physical systems are analyzed and compared. They entered the literature as the generalized uncertainty principle (GUP) assuming modified dispersion relation, and therefore are allowed for a wide range of applications in estimating, for example, the inflationary parameters, Lorentz invariance violation, black hole thermodynamics, Saleker-Wigner inequalities, entropic nature of gravitational laws, Friedmann equations, minimal time measurement and thermodynamics of the high-energy collisions. One of the higher-order GUP approaches gives predictions for the minimal length uncertainty. A second one predicts a maximum momentum and a minimal length uncertainty, simultaneously. An extensive comparison between the different GUP approaches is summarized. We also discuss the GUP impacts on the equivalence principles including the universality of the gravitational redshift and the free fall and law of reciprocal action and on the kinetic energy of composite system. The existence of a minimal length and a maximum momentum accuracy is preferred by various physical observations. The concern about the compatibility with the equivalence principles, the universality of gravitational redshift and the free fall and law of reciprocal action should be addressed. We conclude that the value of the GUP parameters remain a puzzle to be verified.

  19. Acoustic Translation of an Acoustically Levitated Sample

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  20. Manipulating Acoustic Wavefront by Inhomogeneous Impedance and Steerable Extraordinary Reflection

    PubMed Central

    Zhao, Jiajun; Li, Baowen; Chen, Zhining; Qiu, Cheng-Wei

    2013-01-01

    We unveil the connection between the acoustic impedance along a flat surface and the reflected acoustic wavefront, in order to empower a wide wariety of novel applications in acoustic community. Our designed flat surface can generate double reflections: the ordinary reflection and the extraordinary one whose wavefront is manipulated by the proposed impedance-governed generalized Snell's law of reflection (IGSL). IGSL is based on Green's function and integral equation, instead of Fermat's principle for optical wavefront manipulation. Remarkably, via the adjustment of the designed specific acoustic impedance, extraordinary reflection can be steered for unprecedented acoustic wavefront while that ordinary reflection can be surprisingly switched on or off. The realization of the complex discontinuity of the impedance surface has been proposed using Helmholtz resonators. PMID:23985717

  1. Manipulating acoustic wavefront by inhomogeneous impedance and steerable extraordinary reflection.

    PubMed

    Zhao, Jiajun; Li, Baowen; Chen, Zhining; Qiu, Cheng-Wei

    2013-01-01

    We unveil the connection between the acoustic impedance along a flat surface and the reflected acoustic wavefront, in order to empower a wide wariety of novel applications in acoustic community. Our designed flat surface can generate double reflections: the ordinary reflection and the extraordinary one whose wavefront is manipulated by the proposed impedance-governed generalized Snell's law of reflection (IGSL). IGSL is based on Green's function and integral equation, instead of Fermat's principle for optical wavefront manipulation. Remarkably, via the adjustment of the designed specific acoustic impedance, extraordinary reflection can be steered for unprecedented acoustic wavefront while that ordinary reflection can be surprisingly switched on or off. The realization of the complex discontinuity of the impedance surface has been proposed using Helmholtz resonators. PMID:23985717

  2. Manipulating Acoustic Wavefront by Inhomogeneous Impedance and Steerable Extraordinary Reflection

    NASA Astrophysics Data System (ADS)

    Zhao, Jiajun; Li, Baowen; Chen, Zhining; Qiu, Cheng-Wei

    2013-08-01

    We unveil the connection between the acoustic impedance along a flat surface and the reflected acoustic wavefront, in order to empower a wide wariety of novel applications in acoustic community. Our designed flat surface can generate double reflections: the ordinary reflection and the extraordinary one whose wavefront is manipulated by the proposed impedance-governed generalized Snell's law of reflection (IGSL). IGSL is based on Green's function and integral equation, instead of Fermat's principle for optical wavefront manipulation. Remarkably, via the adjustment of the designed specific acoustic impedance, extraordinary reflection can be steered for unprecedented acoustic wavefront while that ordinary reflection can be surprisingly switched on or off. The realization of the complex discontinuity of the impedance surface has been proposed using Helmholtz resonators.

  3. Transverse acoustic trapping using a Gaussian focused ultrasound

    PubMed Central

    Lee, Jungwoo; Teh, Shia-Yen; Lee, Abraham; Kim, Hyung Ham; Lee, Changyang; Shung, K. Kirk

    2009-01-01

    The optical tweezer has become a popular device to manipulate particles in nanometer scales, and to study the underlying principles of many cellular or molecular interactions. Theoretical analysis was previously carried out at the authors’ laboratory, to show that similar acoustic trapping of microparticles may be possible with a single beam ultrasound. This paper experimentally presents the transverse trapping of 125 μm lipid droplets under an acoustically transparent mylar film, which is an intermediate step toward achieving acoustic tweezers in 3D. Despite the lack of axial trapping capability in the current experimental arrangement, it was found that a 30 MHz focused beam could be used to laterally direct the droplets towards the focus. The spatial range within which acoustic traps may guide droplet motion was in the range of hundreds of micrometers, much greater than that of optical traps. This suggests that this acoustic device may offer an alternative for manipulating microparticles in a wider spatial range. PMID:20045590

  4. Nonlinear Acoustics in Fluids

    NASA Astrophysics Data System (ADS)

    Lauterborn, Werner; Kurz, Thomas; Akhatov, Iskander

    At high sound intensities or long propagation distances at in fluids sufficiently low damping acoustic phenomena become nonlinear. This chapter focuses on nonlinear acoustic wave properties in gases and liquids. The origin of nonlinearity, equations of state, simple nonlinear waves, nonlinear acoustic wave equations, shock-wave formation, and interaction of waves are presented and discussed. Tables are given for the nonlinearity parameter B/A for water and a range of organic liquids, liquid metals and gases. Acoustic cavitation with its nonlinear bubble oscillations, pattern formation and sonoluminescence (light from sound) are modern examples of nonlinear acoustics. The language of nonlinear dynamics needed for understanding chaotic dynamics and acoustic chaotic systems is introduced.

  5. Architectural shape and early acoustic efficiency in concert halls (L).

    PubMed

    Jurkiewicz, Yann; Wulfrank, Thomas; Kahle, Eckhard

    2012-09-01

    Supplying sufficient early reflections to audience members is an important prerequisite to good acoustic quality in performing arts spaces. However, the relationship between the geometry of a room and its acoustic efficiency in terms of early energy has rarely been investigated using basic geometrical principles. The present study demonstrates the possibility of predicting the average value of early reflected energy across the audience area using solid angles. The formulas obtained display the influence of various factors on average early energy; in particular, the direction of arrival of early reflections is found to play a significant role, which highlights interesting implications for the acoustic design of concert halls. PMID:22978852

  6. Preliminary characterization of a one-axis acoustic system. [acoustic levitation for space processing

    NASA Technical Reports Server (NTRS)

    Oran, W. A.; Reiss, D. A.; Berge, L. H.; Parker, H. W.

    1979-01-01

    The acoustic fields and levitation forces produced along the axis of a single-axis resonance system were measured. The system consisted of a St. Clair generator and a planar reflector. The levitation force was measured for bodies of various sizes and geometries (i.e., spheres, cylinders, and discs). The force was found to be roughly proportional to the volume of the body until the characteristic body radius reaches approximately 2/k (k = wave number). The acoustic pressures along the axis were modeled using Huygens principle and a method of imaging to approximate multiple reflections. The modeled pressures were found to be in reasonable agreement with those measured with a calibrated microphone.

  7. Near optimal graphene terahertz non-reciprocal isolator

    NASA Astrophysics Data System (ADS)

    Tamagnone, Michele; Moldovan, Clara; Poumirol, Jean-Marie; Kuzmenko, Alexey B.; Ionescu, Adrian M.; Mosig, Juan R.; Perruisseau-Carrier, Julien

    2016-04-01

    Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices.

  8. Near optimal graphene terahertz non-reciprocal isolator.

    PubMed

    Tamagnone, Michele; Moldovan, Clara; Poumirol, Jean-Marie; Kuzmenko, Alexey B; Ionescu, Adrian M; Mosig, Juan R; Perruisseau-Carrier, Julien

    2016-01-01

    Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices. PMID:27048760

  9. Near optimal graphene terahertz non-reciprocal isolator

    PubMed Central

    Tamagnone, Michele; Moldovan, Clara; Poumirol, Jean-Marie; Kuzmenko, Alexey B.; Ionescu, Adrian M.; Mosig, Juan R.; Perruisseau-Carrier, Julien

    2016-01-01

    Isolators, or optical diodes, are devices enabling unidirectional light propagation by using non-reciprocal optical materials, namely materials able to break Lorentz reciprocity. The realization of isolators at terahertz frequencies is a very important open challenge made difficult by the intrinsically lossy propagation of terahertz radiation in current non-reciprocal materials. Here we report the design, fabrication and measurement of a terahertz non-reciprocal isolator for circularly polarized waves based on magnetostatically biased monolayer graphene, operating in reflection. The device exploits the non-reciprocal optical conductivity of graphene and, in spite of its simple design, it exhibits almost 20 dB of isolation and only 7.5 dB of insertion loss at 2.9 THz. Operation with linearly polarized light can be achieved using quarter-wave plates as polarization converters. These results demonstrate the superiority of graphene with respect to currently used terahertz non-reciprocal materials and pave the way to a novel class of optimal non-reciprocal devices. PMID:27048760

  10. Localized acoustic surface modes

    NASA Astrophysics Data System (ADS)

    Farhat, Mohamed; Chen, Pai-Yen; Bağcı, Hakan

    2016-04-01

    We introduce the concept of localized acoustic surface modes. We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  11. Low frequency acoustic microscope

    DOEpatents

    Khuri-Yakub, Butrus T.

    1986-11-04

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

  12. Acoustic dispersive prism.

    PubMed

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

    2016-01-01

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

  13. Acoustic dispersive prism

    PubMed Central

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

    2016-01-01

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

  14. Acoustic dispersive prism

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  15. Linear coupling of acoustic and cyclotron waves in plasma flows

    SciTech Connect

    Rogava, Andria; Gogoberidze, Grigol

    2005-05-15

    It is found that in magnetized electrostatic plasma flows the velocity shear couples ion-acoustic waves with ion-cyclotron waves and leads, under favorable conditions, to their efficient reciprocal transformations. It is shown that in a two-dimensional setup this coupling has a remarkable feature: it is governed by equations that are mathematically equal to the ones describing coupling of sound waves with internal gravity waves [Rogava and Mahajan, Phys. Rev. E 55, 1185 (1997)] in neutral fluids. For flows with low shearing rates a fully analytic, quantitative description of the coupling efficiency, based on a noteworthy quantum-mechanical analogy, is given and transformation coefficients are calculated.

  16. Linear coupling of acoustic and cyclotron waves in plasma flows

    NASA Astrophysics Data System (ADS)

    Rogava, Andria; Gogoberidze, Grigol

    2005-05-01

    It is found that in magnetized electrostatic plasma flows the velocity shear couples ion-acoustic waves with ion-cyclotron waves and leads, under favorable conditions, to their efficient reciprocal transformations. It is shown that in a two-dimensional setup this coupling has a remarkable feature: it is governed by equations that are mathematically equal to the ones describing coupling of sound waves with internal gravity waves [Rogava and Mahajan, Phys. Rev. E 55, 1185 (1997)] in neutral fluids. For flows with low shearing rates a fully analytic, quantitative description of the coupling efficiency, based on a noteworthy quantum-mechanical analogy, is given and transformation coefficients are calculated.

  17. Advanced Natural Gas Reciprocating Engine(s)

    SciTech Connect

    Kwok, Doris; Boucher, Cheryl

    2009-09-30

    Energy independence and fuel savings are hallmarks of the nation’s energy strategy. The advancement of natural gas reciprocating engine power generation technology is critical to the nation’s future. A new engine platform that meets the efficiency, emissions, fuel flexibility, cost and reliability/maintainability targets will enable American manufacturers to have highly competitive products that provide substantial environmental and economic benefits in the US and in international markets. Along with Cummins and Waukesha, Caterpillar participated in a multiyear cooperative agreement with the Department of Energy to create a 50% efficiency natural gas powered reciprocating engine system with a 95% reduction in NOx emissions by the year 2013. This platform developed under this agreement will be a significant contributor to the US energy strategy and will enable gas engine technology to remain a highly competitive choice, meeting customer cost of electricity targets, and regulatory environmental standard. Engine development under the Advanced Reciprocating Engine System (ARES) program was divided into phases, with the ultimate goal being approached in a series of incremental steps. This incremental approach would promote the commercialization of ARES technologies as soon as they emerged from development and would provide a technical and commercial foundation of later-developing technologies. Demonstrations of the Phase I and Phase II technology were completed in 2004 and 2008, respectively. Program tasks in Phase III included component and system development and testing from 2009-2012. Two advanced ignition technology evaluations were investigated under the ARES program: laser ignition and distributed ignition (DIGN). In collaboration with Colorado State University (CSU), a laser ignition system was developed to provide ignition at lean burn and high boost conditions. Much work has been performed in Caterpillar’s DIGN program under the ARES program. This work

  18. Virtual acoustic displays

    NASA Technical Reports Server (NTRS)

    Wenzel, Elizabeth M.

    1991-01-01

    A 3D auditory display can potentially enhance information transfer by combining directional and iconic information in a quite naturalistic representation of dynamic objects in the interface. Another aspect of auditory spatial clues is that, in conjunction with other modalities, it can act as a potentiator of information in the display. For example, visual and auditory cues together can reinforce the information content of the display and provide a greater sense of presence or realism in a manner not readily achievable by either modality alone. This phenomenon will be particularly useful in telepresence applications, such as advanced teleconferencing environments, shared electronic workspaces, and monitoring telerobotic activities in remote or hazardous situations. Thus, the combination of direct spatial cues with good principles of iconic design could provide an extremely powerful and information-rich display which is also quite easy to use. An alternative approach, recently developed at ARC, generates externalized, 3D sound cues over headphones in realtime using digital signal processing. Here, the synthesis technique involves the digital generation of stimuli using Head-Related Transfer Functions (HRTF's) measured in the two ear-canals of individual subjects. Other similar approaches include an analog system developed by Loomis, et. al., (1990) and digital systems which make use of transforms derived from normative mannikins and simulations of room acoustics. Such an interface also requires the careful psychophysical evaluation of listener's ability to accurately localize the virtual or synthetic sound sources. From an applied standpoint, measurement of each potential listener's HRTF's may not be possible in practice. For experienced listeners, localization performance was only slightly degraded compared to a subject's inherent ability. Alternatively, even inexperienced listeners may be able to adapt to a particular set of HRTF's as long as they provide adequate

  19. Focal plane scanner with reciprocating spatial window

    NASA Technical Reports Server (NTRS)

    Mao, Chengye (Inventor)

    2000-01-01

    A focal plane scanner having a front objective lens, a spatial window for selectively passing a portion of the image therethrough, and a CCD array for receiving the passed portion of the image. All embodiments have a common feature whereby the spatial window and CCD array are mounted for simultaneous relative reciprocating movement with respect to the front objective lens, and the spatial window is mounted within the focal plane of the front objective. In a first embodiment, the spatial window is a slit and the CCD array is one-dimensional, and successive rows of the image in the focal plane of the front objective lens are passed to the CCD array by an image relay lens interposed between the slit and the CCD array. In a second embodiment, the spatial window is a slit, the CCD array is two-dimensional, and a prism-grating-prism optical spectrometer is interposed between the slit and the CCD array so as to cause the scanned row to be split into a plurality of spectral separations onto the CCD array. In a third embodiment, the CCD array is two-dimensional and the spatial window is a rectangular linear variable filter (LVF) window, so as to cause the scanned rows impinging on the LVF to be bandpass filtered into spectral components onto the CCD array through an image relay lens interposed between the LVF and the CCD array.

  20. Experimental Assessment of the Reciprocating Feed System

    NASA Technical Reports Server (NTRS)

    Eddleman, David E.; Blackmon, James B.; Morton, Christopher D.

    2006-01-01

    The primary goal of this project was to design, construct, and test a full scale, high pressure simulated propellant feed system test bed that could evaluate the ability of the Reciprocating Feed System (RFS) to provide essentially constant flow rates and pressures to a rocket engine. The two key issues addressed were the effects of the transition of the drain cycle from tank to tank and the benefits of other hardware such as accumulators to provide a constant pressure flow rate out of the RFS. The test bed provided 500 psi flow at rates of the order of those required for engines in the 20,000 lbf thrust class (e.g., 20 to 40 lb/sec). A control system was developed in conjunction with the test article and automated system operation was achieved. Pre-test planning and acceptance activities such as a documented procedure and hazard analysis were conducted and the operation of the test article was approved by, and conducted in coordination with, appropriate NASA Marshall Space Flight Center personnel under a Space Act Agreement. Tests demonstrated successful control of flow rates and pressures.

  1. Acoustics Critical Readiness Review

    NASA Technical Reports Server (NTRS)

    Ballard, Kenny

    2010-01-01

    This presentation reviews the status of the acoustic equipment from the medical operations perspective. Included is information about the acoustic dosimeters, sound level meter, and headphones that are planned for use while on orbit. Finally there is information about on-orbit hearing assessments.

  2. The challenge of acoustics

    NASA Astrophysics Data System (ADS)

    Lord, P.

    1981-01-01

    The various applications of acoustics, including sonar, ultrasonic examination of unborn foetuses and architectural applications, are briefly reviewed. Problems in traffic and industrial noise, auditorium design and explosive noise are considered in more detail. The educational aspects of acoustical science and technology are briefly considered.

  3. Acoustic natural frequency analysis of tree-structure pipeline systems by personal computer

    NASA Astrophysics Data System (ADS)

    Györi, I.; Joó, Gy.

    1986-02-01

    The paper gives the extension of the Schmidt-Kuhlmann method for reciprocating compressor pipeline systems having a tree-structure, consisting of receivers and pipes with an optional number of branchings. It gives a generalized algorithm which makes it possible to mechanize program constructing for the purpose of determining acoustic natural frequencies of complex structures, and it illustrates the use of personal computers—besides the actual numerical calculations—for automatic program-writing as well. The program developed is very useful in design practice for determining the effects caused by modification of the geometric dimensions, and it permits one to shift and avoid harmful acoustic resonances in preliminary planning.

  4. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DMV(s) per reciprocal agreements. In the absence of electronic communication technology, the... information on exchanging and obtaining information with civilian law enforcement agencies concerning... licensing authorities. Upon receipt of written or other official law enforcement communication relative...

  5. Effects of Reciprocal Peer Counseling on College Student Personality Development.

    ERIC Educational Resources Information Center

    McWilliams, Spencer A.

    1979-01-01

    This report describes a project in which college students were briefly trained to work as counselors in reciprocating peer relationships and compares the effectiveness of peer counseling with traditional professional counseling. (JD)

  6. Research on networked manufacturing system for reciprocating pump industry

    NASA Astrophysics Data System (ADS)

    Wu, Yangdong; Qi, Guoning; Xie, Qingsheng; Lu, Yujun

    2005-12-01

    Networked manufacturing is a trend of reciprocating pump industry. According to the enterprises' requirement, the architecture of networked manufacturing system for reciprocating pump industry was proposed, which composed of infrastructure layer, system management layer, application service layer and user layer. Its main functions included product data management, ASP service, business management, and customer relationship management, its physics framework was a multi-tier internet-based model; the concept of ASP service integration was put forward and its process model was also established. As a result, a networked manufacturing system aimed at the characteristics of reciprocating pump industry was built. By implementing this system, reciprocating pump industry can obtain a new way to fully utilize their own resources and enhance the capabilities to respond to the global market quickly.

  7. 19. View northwest of Tropic Chamber reciprocal compressors (typical), in ...

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

    19. View northwest of Tropic Chamber reciprocal compressors (typical), in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

  8. The Behm Acoustic Sounder for Airplanes with Reference to Its Accuracy

    NASA Technical Reports Server (NTRS)

    Schreiber, Ernest

    1930-01-01

    Relative altimetry is of great importance for increasing the safety in aerial transportation, because it makes possible safe flying at night, by poor visibility, and when landing. Among the instruments of this type is the Behm sounder, which operates on an acoustic principle. Acoustic altimetry in general and the Behn sounder, in particular, are covered in this report.

  9. Nonlinear ion acoustic waves scattered by vortexes

    NASA Astrophysics Data System (ADS)

    Ohno, Yuji; Yoshida, Zensho

    2016-09-01

    The Kadomtsev-Petviashvili (KP) hierarchy is the archetype of infinite-dimensional integrable systems, which describes nonlinear ion acoustic waves in two-dimensional space. This remarkably ordered system resides on a singular submanifold (leaf) embedded in a larger phase space of more general ion acoustic waves (low-frequency electrostatic perturbations). The KP hierarchy is characterized not only by small amplitudes but also by irrotational (zero-vorticity) velocity fields. In fact, the KP equation is derived by eliminating vorticity at every order of the reductive perturbation. Here, we modify the scaling of the velocity field so as to introduce a vortex term. The newly derived system of equations consists of a generalized three-dimensional KP equation and a two-dimensional vortex equation. The former describes 'scattering' of vortex-free waves by ambient vortexes that are determined by the latter. We say that the vortexes are 'ambient' because they do not receive reciprocal reactions from the waves (i.e., the vortex equation is independent of the wave fields). This model describes a minimal departure from the integrable KP system. By the Painlevé test, we delineate how the vorticity term violates integrability, bringing about an essential three-dimensionality to the solutions. By numerical simulation, we show how the solitons are scattered by vortexes and become chaotic.

  10. Selectively manipulable acoustic-powered microswimmers

    PubMed Central

    Ahmed, Daniel; Lu, Mengqian; Nourhani, Amir; Lammert, Paul E.; Stratton, Zak; Muddana, Hari S.; Crespi, Vincent H.; Huang, Tony Jun

    2015-01-01

    Selective actuation of a single microswimmer from within a diverse group would be a first step toward collaborative guided action by a group of swimmers. Here we describe a new class of microswimmer that accomplishes this goal. Our swimmer design overcomes the commonly-held design paradigm that microswimmers must use non-reciprocal motion to achieve propulsion; instead, the swimmer is propelled by oscillatory motion of an air bubble trapped within the swimmer's polymer body. This oscillatory motion is driven by the application of a low-power acoustic field, which is biocompatible with biological samples and with the ambient liquid. This acoustically-powered microswimmer accomplishes controllable and rapid translational and rotational motion, even in highly viscous liquids (with viscosity 6,000 times higher than that of water). And by using a group of swimmers each with a unique bubble size (and resulting unique resonance frequencies), selective actuation of a single swimmer from among the group can be readily achieved. PMID:25993314

  11. Highly directional acoustic receivers.

    PubMed

    Cray, Benjamin A; Evora, Victor M; Nuttall, Albert H

    2003-03-01

    The theoretical directivity of a single combined acoustic receiver, a device that can measure many quantities of an acoustic field at a collocated point, is presented here. The formulation is developed using a Taylor series expansion of acoustic pressure about the origin of a Cartesian coordinate system. For example, the quantities measured by a second-order combined receiver, denoted a dyadic sensor, are acoustic pressure, the three orthogonal components of acoustic particle velocity, and the nine spatial gradients of the velocity vector. The power series expansion, which can be of any order, is cast into an expression that defines the directivity of a single receiving element. It is shown that a single highly directional dyadic sensor can have a directivity index of up to 9.5 dB. However, there is a price to pay with highly directive sensors; these sensors can be significantly more sensitive to nonacoustic noise sources. PMID:12656387

  12. Ocean acoustic hurricane classification.

    PubMed

    Wilson, Joshua D; Makris, Nicholas C

    2006-01-01

    Theoretical and empirical evidence are combined to show that underwater acoustic sensing techniques may be valuable for measuring the wind speed and determining the destructive power of a hurricane. This is done by first developing a model for the acoustic intensity and mutual intensity in an ocean waveguide due to a hurricane and then determining the relationship between local wind speed and underwater acoustic intensity. From this it is shown that it should be feasible to accurately measure the local wind speed and classify the destructive power of a hurricane if its eye wall passes directly over a single underwater acoustic sensor. The potential advantages and disadvantages of the proposed acoustic method are weighed against those of currently employed techniques. PMID:16454274

  13. Acoustic Remote Sensing

    NASA Astrophysics Data System (ADS)

    Dowling, David R.; Sabra, Karim G.

    2015-01-01

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

  14. Acoustic integrated extinction

    PubMed Central

    Norris, Andrew N.

    2015-01-01

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

  15. Virtual acoustics displays

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  16. Cochlear bionic acoustic metamaterials

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  17. 14 CFR 121.175 - Airplanes: Reciprocating engine-powered: Weight limitations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) No person may take off a reciprocating engine powered airplane from an airport located at an...) No person may take off a reciprocating engine powered airplane for an airport of intended destination... the reciprocating engine powered airplane concerned. (d) No person may take off a reciprocating...

  18. A review of the generalized uncertainty principle

    NASA Astrophysics Data System (ADS)

    Nasser Tawfik, Abdel; Magied Diab, Abdel

    2015-12-01

    Based on string theory, black hole physics, doubly special relativity and some ‘thought’ experiments, minimal distance and/or maximum momentum are proposed. As alternatives to the generalized uncertainty principle (GUP), the modified dispersion relation, the space noncommutativity, the Lorentz invariance violation, and the quantum-gravity-induced birefringence effects are summarized. The origin of minimal measurable quantities and the different GUP approaches are reviewed and the corresponding observations are analysed. Bounds on the GUP parameter are discussed and implemented in the understanding of recent PLANCK observations of cosmic inflation. The higher-order GUP approaches predict minimal length uncertainty with and without maximum momenta. Possible arguments against the GUP are discussed; for instance, the concern about its compatibility with the equivalence principles, the universality of gravitational redshift and the free fall and law of reciprocal action are addressed.

  19. A review of the generalized uncertainty principle.

    PubMed

    Tawfik, Abdel Nasser; Diab, Abdel Magied

    2015-12-01

    Based on string theory, black hole physics, doubly special relativity and some 'thought' experiments, minimal distance and/or maximum momentum are proposed. As alternatives to the generalized uncertainty principle (GUP), the modified dispersion relation, the space noncommutativity, the Lorentz invariance violation, and the quantum-gravity-induced birefringence effects are summarized. The origin of minimal measurable quantities and the different GUP approaches are reviewed and the corresponding observations are analysed. Bounds on the GUP parameter are discussed and implemented in the understanding of recent PLANCK observations of cosmic inflation. The higher-order GUP approaches predict minimal length uncertainty with and without maximum momenta. Possible arguments against the GUP are discussed; for instance, the concern about its compatibility with the equivalence principles, the universality of gravitational redshift and the free fall and law of reciprocal action are addressed. PMID:26512022

  20. Bah humbug: Unexpected Christmas cards and the reciprocity norm.

    PubMed

    Meier, Brian P

    2016-01-01

    The reciprocity norm refers to the expectation that people will help those who helped them. A well-known study revealed that the norm is strong with Christmas cards, with 20% of people reciprocating a Christmas card received from a stranger. I attempted to conceptually replicate and extend this effect. In Study 1, 755 participants received a Christmas card supposedly from a more- versus less-similar stranger. The reciprocation rate was unexpectedly low (2%), which did not allow for a test of a similarity effect. Two potential reasons for this low rate were examined in Study 2 in which 494 participants reported their likelihood of reciprocating a Christmas card from a stranger as well as their felt suspicions/threat about the card and their frequency of e-mail use. Reciprocation likelihood was negatively correlated with perceived threat/suspicion and e-mail use. It appears that reciprocating a gift from a stranger in offline settings may be less likely than expected. PMID:26666577

  1. Ocean seismo-acoustics. Low-frequency underwater acoustics

    SciTech Connect

    Akal, T.; berkson, J.M.

    1986-01-01

    This book presents information on seismo-acoustic propagation in seawater and sea beds that includes theoretical developments, modelling and experiments, and fluctuations. Boundary scatteiring, seismo-acoustic waves and seismo-acoustic noise are discussed. Technology and new approaches in seismo-acoustic measurements are presented.

  2. Analytical Assessment of the Reciprocating Feed System

    NASA Technical Reports Server (NTRS)

    Eddleman, David E.; Blackmon, James B.; Morton, Christopher D.

    2006-01-01

    A preliminary analysis tool has been created in Microsoft Excel to determine deliverable payload mass, total system mass, and performance of spacecraft systems using various types of propellant feed systems. These mass estimates are conducted by inserting into the user interface the basic mission parameters (e.g., thrust, burn time, specific impulse, mixture ratio, etc.), system architecture (e.g., propulsion system type and characteristics, propellants, pressurization system type, etc.), and design properties (e.g., material properties, safety factors, etc.). Different propellant feed and pressurization systems are available for comparison in the program. This gives the user the ability to compare conventional pressure fed, reciprocating feed system (RFS), autogenous pressurization thrust augmentation (APTA RFS), and turbopump systems with the deliverable payload, inert mass, and total system mass being the primary comparison metrics. Analyses of several types of missions and spacecraft were conducted and it was found that the RFS offers a performance improvement, especially in terms of delivered payload, over conventional pressure fed systems. Furthermore, it is competitive with a turbopump system at low to moderate chamber pressures, up to approximately 1,500 psi. Various example cases estimating the system mass and deliverable payload of several types of spacecraft are presented that illustrate the potential system performance advantages of the RFS. In addition, a reliability assessment of the RFS was conducted, comparing it to simplified conventional pressure fed and turbopump systems, based on MIL-STD 756B; these results showed that the RFS offers higher reliability, and thus substantially longer periods between system refurbishment, than turbopump systems, and is competitive with conventional pressure fed systems. This is primarily the result of the intrinsic RFS fail-operational capability with three run tanks, since the system can operate with just two run

  3. Optimal performance of reciprocating demagnetization quantum refrigerators

    NASA Astrophysics Data System (ADS)

    Kosloff, Ronnie; Feldmann, Tova

    2010-07-01

    A reciprocating quantum refrigerator is studied with the purpose of determining the limitations of cooling to absolute zero. The cycle is based on demagnetization and magnetization of a working medium. We find that if the energy spectrum of the working medium possesses an uncontrollable gap, and in addition there is noise on the controls, then there is a minimum achievable temperature above zero. The reason is that even a negligible amount of noise prevents adiabatic following during the demagnetization stage. This results with a minimum temperature, Tc(min)>0 , which scales with the energy gap. The refrigerator is based on an Otto cycle where the working medium is an interacting spin system with an energy gap. For this system the external control Hamiltonian does not commute with the internal interaction. As a result during the demagnetization and magnetization segments of the operating cycle the system cannot follow adiabatically the temporal change in the energy levels. We connect the nonadiabatic dynamics to quantum friction. An adiabatic measure is defined characterizing the rate of change of the Hamiltonian. Closed-form solutions are found for a constant adiabatic measure for all the cycle segments. We have identified a family of quantized frictionless cycles with increasing cycle times. These cycles minimize the entropy production. Such frictionless cycles are able to cool to Tc=0 . External noise on the controls eliminates these frictionless cycles. The influence of phase and amplitude noise on the demagnetization and magnetization segments is explicitly derived. An extensive numerical study of optimal cooling cycles was carried out which showed that at sufficiently low temperature the noise always dominated restricting the minimum temperature.

  4. Reciprocating flow-based centrifugal microfluidics mixer

    NASA Astrophysics Data System (ADS)

    Noroozi, Zahra; Kido, Horacio; Micic, Miodrag; Pan, Hansheng; Bartolome, Christian; Princevac, Marko; Zoval, Jim; Madou, Marc

    2009-07-01

    Proper mixing of reagents is of paramount importance for an efficient chemical reaction. While on a large scale there are many good solutions for quantitative mixing of reagents, as of today, efficient and inexpensive fluid mixing in the nanoliter and microliter volume range is still a challenge. Complete, i.e., quantitative mixing is of special importance in any small-scale analytical application because the scarcity of analytes and the low volume of the reagents demand efficient utilization of all available reaction components. In this paper we demonstrate the design and fabrication of a novel centrifugal force-based unit for fast mixing of fluids in the nanoliter to microliter volume range. The device consists of a number of chambers (including two loading chambers, one pressure chamber, and one mixing chamber) that are connected through a network of microchannels, and is made by bonding a slab of polydimethylsiloxane (PDMS) to a glass slide. The PDMS slab was cast using a SU-8 master mold fabricated by a two-level photolithography process. This microfluidic mixer exploits centrifugal force and pneumatic pressure to reciprocate the flow of fluid samples in order to minimize the amount of sample and the time of mixing. The process of mixing was monitored by utilizing the planar laser induced fluorescence (PLIF) technique. A time series of high resolution images of the mixing chamber were analyzed for the spatial distribution of light intensities as the two fluids (suspension of red fluorescent particles and water) mixed. Histograms of the fluorescent emissions within the mixing chamber during different stages of the mixing process were created to quantify the level of mixing of the mixing fluids. The results suggest that quantitative mixing was achieved in less than 3 min. This device can be employed as a stand alone mixing unit or may be integrated into a disk-based microfluidic system where, in addition to mixing, several other sample preparation steps may be

  5. Blending History with Physics: Acoustic Shadows in the Civil War

    NASA Astrophysics Data System (ADS)

    Ross, Charles D.

    1998-04-01

    To spark student interest in and broaden student perspectives of certain physics principles, it is useful to show how these principles have dramatically affected the course of history. In this case, the study of refraction is enhanced by looking at the results of an original study of the causes of acoustic shadows in the U.S. Civil War and their effect on command decisions in important battles.

  6. Nearfield acoustic holography. I - Theory of generalized holography and the development of NAH

    NASA Technical Reports Server (NTRS)

    Maynard, J. D.; Williams, E. G.; Lee, Y.

    1985-01-01

    Because its underlying principles are so fundamental, holography has been studied and applied in many areas of science. Recently, a technique has been developed which takes the maximum advantage of the fundamental principles and extracts much more information from a hologram than is customarily associated with such a measurement. In this paper the fundamental principles of holography are reviewed, and a sound radiation measurement system, called nearfield acoustic holography (NAH), which fully exploits the fundamental principles, is described.

  7. Acoustic cooling engine

    DOEpatents

    Hofler, Thomas J.; Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1988-01-01

    An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element. The hot heat exchanger conducts heat from the first end to portions of the resonant pressure vessel proximate the hot heat exchanger. The hot heat exchanger permits substantial flow of the fluid through the hot heat exchanger. The resonant pressure vessel can include a housing less than one quarter wavelength in length coupled to a reservoir. The housing can include a reduced diameter portion communicating with the reservoir. The frequency of the acoustic driver can be continuously controlled so as to maintain resonance.

  8. Acoustic mapping velocimetry

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  9. Cultural Reciprocity in Sociocultural Perspective: Adapting the Normalization Principle for Family Collaboration.

    ERIC Educational Resources Information Center

    Harry, Beth; Rueda, Robert; Kalyanpur, Maya

    1999-01-01

    Findings from a collaborative action research project involving seven culturally diverse families with children with disabilities are used to illustrate how professionals can provide assistance in a family's zone of proximal development, rather than targeting goals that are normative for the mainstream, but not for the family. (Author/CR)

  10. Equivalence principles and electromagnetism

    NASA Technical Reports Server (NTRS)

    Ni, W.-T.

    1977-01-01

    The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.

  11. Some Problems of modern acoustics

    NASA Technical Reports Server (NTRS)

    Stan, A.

    1974-01-01

    The multidisciplinary and interdisciplinary character of acoustics is considered and its scientific, technological, economical and social implications, as well as the role of acoustics in creating new machines and equipment and improving the quality of products are outlined. Research beyond audible frequencies, as well as to extremely high acoustic intensities, which requires the development of a nonlinear acoustics is elaborated.

  12. Acoustic well cleaner

    DOEpatents

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

    1997-01-21

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

  13. Acoustic rotation control

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.; Croonquist, A. P.; Wang, T. G. (Inventor)

    1983-01-01

    A system is described for acoustically controlled rotation of a levitated object, which avoids deformation of a levitated liquid object. Acoustic waves of the same wavelength are directed along perpendicular directions across the object, and with the relative phases of the acoustic waves repeatedly switched so that one wave alternately leads and lags the other by 90 deg. The amount of torque for rotating the object, and the direction of rotation, are controlled by controlling the proportion of time one wave leads the other and selecting which wave leads the other most of the time.

  14. PRSEUS Acoustic Panel Fabrication

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  15. Acoustical heat pumping engine

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1983-08-16

    The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium.

  16. Acoustical heat pumping engine

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1983-08-16

    The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium. 2 figs.

  17. What leads to romantic attraction: similarity, reciprocity, security, or beauty? Evidence from a speed-dating study.

    PubMed

    Luo, Shanhong; Zhang, Guangjian

    2009-08-01

    Years of attraction research have established several "principles" of attraction with robust evidence. However, a major limitation of previous attraction studies is that they have almost exclusively relied on well-controlled experiments, which are often criticized for lacking ecological validity. The current research was designed to examine initial attraction in a real-life setting-speed-dating. Social Relations Model analyses demonstrated that initial attraction was a function of the actor, the partner, and the unique dyadic relationship between these two. Meta-analyses showed intriguing sex differences and similarities. Self characteristics better predicted women's attraction than they did for men, whereas partner characteristics predicted men's attraction far better than they did for women. The strongest predictor of attraction for both sexes was partners' physical attractiveness. Finally, there was some support for the reciprocity principle but no evidence for the similarity principle. PMID:19558447

  18. Fifty years of progress in acoustic phonetics

    NASA Astrophysics Data System (ADS)

    Stevens, Kenneth N.

    2004-10-01

    Three events that occurred 50 or 60 years ago shaped the study of acoustic phonetics, and in the following few decades these events influenced research and applications in speech disorders, speech development, speech synthesis, speech recognition, and other subareas in speech communication. These events were: (1) the source-filter theory of speech production (Chiba and Kajiyama; Fant); (2) the development of the sound spectrograph and its interpretation (Potter, Kopp, and Green; Joos); and (3) the birth of research that related distinctive features to acoustic patterns (Jakobson, Fant, and Halle). Following these events there has been systematic exploration of the articulatory, acoustic, and perceptual bases of phonological categories, and some quantification of the sources of variability in the transformation of this phonological representation of speech into its acoustic manifestations. This effort has been enhanced by studies of how children acquire language in spite of this variability and by research on speech disorders. Gaps in our knowledge of this inherent variability in speech have limited the directions of applications such as synthesis and recognition of speech, and have led to the implementation of data-driven techniques rather than theoretical principles. Some examples of advances in our knowledge, and limitations of this knowledge, are reviewed.

  19. FIELD TESTING OF PROTOTYPE ACOUSTIC EMISSION SEWER FLOWMETER

    EPA Science Inventory

    This investigation concerns verifying the operating principles of the acoustic emission flowmeter (U.S. Patent 3,958,458) in the natural environment of three different storm sewer field sites in Nassau County, New York. The flowmeter is a novel, passive, nonintrusive method that ...

  20. Acoustical Environments. Educational Facilities Review Series Number 16.

    ERIC Educational Resources Information Center

    Baas, Alan M.

    This review surveys documents and journal articles previously announced in RIE and CIJE that deal with the principles and techniques of sound transmission and control, particularly as they relate to school environments. School planners and administrators are advised that excessive acoustical insulation costs may be avoided by early decisions…

  1. Philosophical and cultural perspectives on acoustics in Vedic Hinduism

    NASA Astrophysics Data System (ADS)

    Prasad, M. G.

    2001-05-01

    Acoustics plays a very important multi-faceted role in Vedic Hinduism. Vedas, that is an infinitely large collection of chants (mantras) in ancient Sanskrit language, form the foundational literature of Vedic Hinduism. The Vedic chants have specific acoustical qualities and intonations. The Vedic literature describes the various aspects of acoustics, namely, philosophical, spiritual, and cultural. The use of sounds from conch-shell, bells, cymbal in addition to the Vedic chants in rituals shows the spiritual aspects. Vedic literature discusses the role of sound in the philosophical understanding of our world. Music, both vocal and instrumental, plays an important role in the cultural aspects of Vedic Hinduism. It can be seen that certain musical instruments such as ``mridangam,'' a percussion drum, reflect scientific principles underlying in their design. This paper presents an overview of the various important and interesting roles of acoustics in Vedic Hinduism.

  2. Spatial autocorrelation of radiation measured by the Earth Radiation Budget Experiment: Scene inhomogeneity and reciprocity violation

    NASA Technical Reports Server (NTRS)

    Davies, Roger

    1994-01-01

    The spatial autocorrelation functions of broad-band longwave and shortwave radiances measured by the Earth Radiation Budget Experiment (ERBE) are analyzed as a function of view angle in an investigation of the general effects of scene inhomogeneity on radiation. For nadir views, the correlation distance of the autocorrelation function is about 900 km for longwave radiance and about 500 km for shortwave radiance, consistent with higher degrees of freedom in shortwave reflection. Both functions rise monotonically with view angle, but there is a substantial difference in the relative angular dependence of the shortwave and longwave functions, especially for view angles less than 50 deg. In this range, the increase with angle of the longwave functions is found to depend only on the expansion of pixel area with angle, whereas the shortwave functions show an additional dependence on angle that is attributed to the occlusion of inhomogeneities by cloud height variations. Beyond a view angle of about 50 deg, both longwave and shortwave functions appear to be affected by cloud sides. The shortwave autocorrelation functions do not satisfy the principle of directional reciprocity, thereby proving that the average scene is horizontally inhomogeneous over the scale of an ERBE pixel (1500 sq km). Coarse stratification of the measurements by cloud amount, however, indicates that the average cloud-free scene does satisfy directional reciprocity on this scale.

  3. Acoustic Neuroma Association

    MedlinePlus

    ... Platinum Sponsors More from this sponsor... Platinum Sponsor Gold Sponsor University of Colorado Acoustic Neuroma Program Rocky Mountain Gamma Knife Center Gold Sponsor NYU Langone Medical Center Departments of Neurosurgery ...

  4. Compact acoustic refrigerator

    DOEpatents

    Bennett, Gloria A.

    1992-01-01

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.

  5. Acoustic imaging system

    DOEpatents

    Smith, Richard W.

    1979-01-01

    An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

  6. Acoustics lecturing in Mexico

    NASA Astrophysics Data System (ADS)

    Beristain, Sergio

    2002-11-01

    Some thirty years ago acoustics lecturing started in Mexico at the National Polytechnic Institute in Mexico City, as part of the Bachelor of Science degree in Communications and Electronics Engineering curricula, including the widest program on this field in the whole country. This program has been producing acoustics specialists ever since. Nowadays many universities and superior education institutions around the country are teaching students at the B.Sc. level and postgraduate level many topics related to acoustics, such as Architectural Acoustics, Seismology, Mechanical Vibrations, Noise Control, Audio, Audiology, Music, etc. Also many institutions have started research programs in related fields, with participation of medical doctors, psychologists, musicians, engineers, etc. Details will be given on particular topics and development.

  7. Compact acoustic refrigerator

    SciTech Connect

    Bennett, G.A.

    1991-12-31

    This invention is comprised of a compact acoustic refrigeration system that actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment.

  8. Compact acoustic refrigerator

    DOEpatents

    Bennett, G.A.

    1992-11-24

    A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.

  9. Two-dimensional acoustic metamaterial structure for potential image processing

    NASA Astrophysics Data System (ADS)

    Sun, Hongwei; Han, Yu; Li, Ying; Pai, Frank

    2015-12-01

    This paper presents modeling, analysis techniques and experiment of for two-Dimensional Acoustic metamaterial Structure for filtering acoustic waves. For a unit cell of an infinite two-Dimensional Acoustic metamaterial Structure, governing equations are derived using the extended Hamilton principle. The concepts of negative effective mass and stiffness and how the spring-mass-damper subsystems create a stopband are explained in detail. Numerical simulations reveal that the actual working mechanism of the proposed acoustic metamaterial structure is based on the concept of conventional mechanical vibration absorbers. It uses the incoming wave in the structure to resonate the integrated membrane-mass-damper absorbers to vibrate in their optical mode at frequencies close to but above their local resonance frequencies to create shear forces and bending moments to straighten the panel and stop the wave propagation. Moreover, a two-dimension acoustic metamaterial structure consisting of lumped mass and elastic membrane is fabricated in the lab. We do experiments on the model and The results validate the concept and show that, for two-dimension acoustic metamaterial structure do exist two vibration modes. For the wave absorption, the mass of each cell should be considered in the design. With appropriate design calculations, the proposed two-dimension acoustic metamaterial structure can be used for absorption of low-frequency waves. Hence this special structure can be used in filtering the waves, and the potential using can increase the ultrasonic imaging quality.

  10. Numerical Techniques in Acoustics

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J. (Compiler)

    1985-01-01

    This is the compilation of abstracts of the Numerical Techniques in Acoustics Forum held at the ASME's Winter Annual Meeting. This forum was for informal presentation and information exchange of ongoing acoustic work in finite elements, finite difference, boundary elements and other numerical approaches. As part of this forum, it was intended to allow the participants time to raise questions on unresolved problems and to generate discussions on possible approaches and methods of solution.

  11. Photoacoustic tomography: principles and advances

    PubMed Central

    Xia, Jun; Yao, Junjie; Wang, Lihong V.

    2014-01-01

    Photoacoustic tomography (PAT) is an emerging imaging modality that shows great potential for preclinical research and clinical practice. As a hybrid technique, PAT is based on the acoustic detection of optical absorption from either endogenous chromophores, such as oxy-hemoglobin and deoxy-hemoglobin, or exogenous contrast agents, such as organic dyes and nanoparticles. Because ultrasound scatters much less than light in tissue, PAT generates high-resolution images in both the optical ballistic and diffusive regimes. Over the past decade, the photoacoustic technique has been evolving rapidly, leading to a variety of exciting discoveries and applications. This review covers the basic principles of PAT and its different implementations. Strengths of PAT are highlighted, along with the most recent imaging results. PMID:25642127

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

    PubMed

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

    2014-01-01

    Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell's law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications. PMID:25418084

  13. Reciprocal and unidirectional scattering of parity-time symmetric structures.

    PubMed

    Jin, L; Zhang, X Z; Zhang, G; Song, Z

    2016-01-01

    Parity-time (PT) symmetry is of great interest. The reciprocal and unidirectional features are intriguing besides the (PT) symmetry phase transition. Recently, the reciprocal transmission, unidirectional reflectionless and invisibility are intensively studied. Here, we show the reciprocal reflection/transmission in (PT)-symmetric system is closely related to the type of (PT) symmetry, that is, the axial (reflection) (PT) symmetry leads to reciprocal reflection (transmission). The results are further elucidated by studying the scattering of rhombic ring form coupled resonators with enclosed synthetic magnetic flux. The nonreciprocal phase shift induced by the magnetic flux and gain/loss break the parity (P) and time-reversal (T) symmetry but keep the parity-time (PT) symmetry. The reciprocal reflection (transmission) and unidirectional transmission (reflection) are found in the axial (reflection) (PT)-symmetric ring centre. The explorations of symmetry and asymmetry from (PT) symmetry may shed light on novel one-way optical devices and application of (PT)-symmetric metamaterials. PMID:26876806

  14. Two dimensional nanoscale reciprocating sliding contacts of textured surfaces

    NASA Astrophysics Data System (ADS)

    Tong, Ruiting; Liu, Geng; Liu, Tianxiang

    2016-05-01

    Detailed behaviors of nanoscale textured surfaces during the reciprocating sliding contacts are still unknown although they are widely used in mechanical components to improve tribological characteristics. The current research of sliding contacts of textured surfaces mainly focuses on the experimental studies, while the cost is too high. Molecular dynamics(MD) simulation is widely used in the studies of nanoscale single-pass sliding contacts, but the CPU cost of MD simulation is also too high to simulate the reciprocating sliding contacts. In this paper, employing multiscale method which couples molecular dynamics simulation and finite element method, two dimensional nanoscale reciprocating sliding contacts of textured surfaces are investigated. Four textured surfaces with different texture shapes are designed, and a rigid cylindrical tip is used to slide on these textured surfaces. For different textured surfaces, average potential energies and average friction forces of the corresponding sliding processes are analyzed. The analyzing results show that "running-in" stages are different for each texture, and steady friction processes are discovered for textured surfaces II, III and IV. Texture shape and sliding direction play important roles in reciprocating sliding contacts, which influence average friction forces greatly. This research can help to design textured surfaces to improve tribological behaviors in nanoscale reciprocating sliding contacts.

  15. Reciprocal translocations in Saccharomyces cerevisiae formed by nonhomologous end joining.

    PubMed

    Yu, Xin; Gabriel, Abram

    2004-02-01

    Reciprocal translocations are common in cancer cells, but their creation is poorly understood. We have developed an assay system in Saccharomyces cerevisiae to study reciprocal translocation formation in the absence of homology. We induce two specific double-strand breaks (DSBs) simultaneously on separate chromosomes with HO endonuclease and analyze the subsequent chromosomal rearrangements among surviving cells. Under these conditions, reciprocal translocations via nonhomologous end joining (NHEJ) occur at frequencies of approximately 2-7 x 10(-5)/cell exposed to the DSBs. Yku80p is a component of the cell's NHEJ machinery. In its absence, reciprocal translocations still occur, but the junctions are associated with deletions and extended overlapping sequences. After induction of a single DSB, translocations and inversions are recovered in wild-type and rad52 strains. In these rearrangements, a nonrandom assortment of sites have fused to the DSB, and their junctions show typical signs of NHEJ. The sites tend to be between open reading frames or within Ty1 LTRs. In some cases the translocation partner is formed by a break at a cryptic HO recognition site. Our results demonstrate that NHEJ-mediated reciprocal translocations can form in S. cerevisiae as a consequence of DSB repair. PMID:15020464

  16. Two dimensional nanoscale reciprocating sliding contacts of textured surfaces

    NASA Astrophysics Data System (ADS)

    Tong, Ruiting; Liu, Geng; Liu, Tianxiang

    2016-04-01

    Detailed behaviors of nanoscale textured surfaces during the reciprocating sliding contacts are still unknown although they are widely used in mechanical components to improve tribological characteristics. The current research of sliding contacts of textured surfaces mainly focuses on the experimental studies, while the cost is too high. Molecular dynamics(MD) simulation is widely used in the studies of nanoscale single-pass sliding contacts, but the CPU cost of MD simulation is also too high to simulate the reciprocating sliding contacts. In this paper, employing multiscale method which couples molecular dynamics simulation and finite element method, two dimensional nanoscale reciprocating sliding contacts of textured surfaces are investigated. Four textured surfaces with different texture shapes are designed, and a rigid cylindrical tip is used to slide on these textured surfaces. For different textured surfaces, average potential energies and average friction forces of the corresponding sliding processes are analyzed. The analyzing results show that "running-in" stages are different for each texture, and steady friction processes are discovered for textured surfaces II, III and IV. Texture shape and sliding direction play important roles in reciprocating sliding contacts, which influence average friction forces greatly. This research can help to design textured surfaces to improve tribological behaviors in nanoscale reciprocating sliding contacts.

  17. Acoustic communication by ants

    NASA Astrophysics Data System (ADS)

    Hickling, Robert

    2002-05-01

    Many ant species communicate acoustically by stridulating, i.e., running a scraper over a washboard-like set of ridges. Ants appear to be insensitive to airborne sound. Consequently, myrmecologists have concluded that the stridulatory signals are transmitted through the substrate. This has tended to diminish the importance of acoustic communication, and it is currently believed that ant communication is based almost exclusively on pheromones, with acoustic communication assigned an almost nonexistent role. However, it can be shown that acoustic communication between ants is effective only if the medium is air and not the substrate. How, then, is it possible for ants to appear deaf to airborne sound and yet communicate through the air? An explanation is provided in a paper [R. Hickling and R. L. Brown, ``Analysis of acoustic communication by ants,'' J. Acoust. Soc. Am. 108, 1920-1929 (2000)]. Ants are small relative to the wavelengths they generate. Hence, they create a near field, which is characterized by a major increase in sound velocity (particle velocity of sound) in the vicinity of the source. Hair sensilla on the ants' antennae respond to sound velocity. Thus, ants are able to detect near-field sound from other ants and to exclude extraneous airborne sound.

  18. Acoustic detection of pneumothorax

    NASA Astrophysics Data System (ADS)

    Mansy, Hansen A.; Royston, Thomas J.; Balk, Robert A.; Sandler, Richard H.

    2003-04-01

    This study aims at investigating the feasibility of using low-frequency (<2000 Hz) acoustic methods for medical diagnosis. Several candidate methods of pneumothorax detection were tested in dogs. In the first approach, broadband acoustic signals were introduced into the trachea during end-expiration and transmitted waves were measured at the chest surface. Pneumothorax was found to consistently decrease pulmonary acoustic transmission in the 200-1200-Hz frequency band, while less change was observed at lower frequencies (p<0.0001). The ratio of acoustic energy between low (<220 Hz) and mid (550-770 Hz) frequency bands was significantly different in the control (healthy) and pneumothorax states (p<0.0001). The second approach measured breath sounds in the absence of an external acoustic input. Pneumothorax was found to be associated with a preferential reduction of sound amplitude in the 200- to 700-Hz range, and a decrease of sound amplitude variation (in the 300 to 600-Hz band) during the respiration cycle (p<0.01 for each). Finally, chest percussion was implemented. Pneumothorax changed the frequency and decay rate of percussive sounds. These results imply that certain medical conditions may be reliably detected using appropriate acoustic measurements and analysis. [Work supported by NIH/NHLBI #R44HL61108.

  19. Ocean acoustic reverberation tomography.

    PubMed

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography. PMID:26723303

  20. Acoustic microstreaming applied to batch micromixing

    NASA Astrophysics Data System (ADS)

    Manasseh, Richard; Petkovic-Duran, Karolina; Tho, Paul; Zhu, Yonggang; Ooi, Andrew

    2006-01-01

    Experiments are presented in which acoustic microstreaming is investigated and applied to a batch micromixing case appropriate to a point-of-care pathology screening test. The flows presented can be created without complex engineering of contacts or surfaces in the microdevice, which could thus be made disposable. Fundamental flow patterns are measured with a micro-Particle-Image Velocimetry (micro-PIV) system, enabling a quantification of the fluiddynamical processes causing the flows. The design of micromixers based on this principle requires a quantification of the mixing. A simple technique based on digital image processing is presented that enables an assessment of the improvement in mixing due to acoustic microstreaming. The digital image processing technique developed was shown to be non-intrusive, convenient and able to generate useful quantitative data. Preliminary indications are that microstreaming can at least halve the time required to mix quantities of liquid typical of a point-of-care test, and significantly greater improvements seem feasible.

  1. Modeling of Structural-Acoustic Interaction Using Coupled FE/BE Method and Control of Interior Acoustic Pressure Using Piezoelectric Actuators

    NASA Technical Reports Server (NTRS)

    Mei, Chuh; Shi, Yacheng

    1997-01-01

    A coupled finite element (FE) and boundary element (BE) approach is presented to model full coupled structural/acoustic/piezoelectric systems. The dual reciprocity boundary element method is used so that the natural frequencies and mode shapes of the coupled system can be obtained, and to extend this approach to time dependent problems. The boundary element method is applied to interior acoustic domains, and the results are very accurate when compared with limited exact solutions. Structural-acoustic problems are then analyzed with the coupled finite element/boundary element method, where the finite element method models the structural domain and the boundary element method models the acoustic domain. Results for a system consisting of an isotropic panel and a cubic cavity are in good agreement with exact solutions and experiment data. The response of a composite panel backed cavity is then obtained. The results show that the mass and stiffness of piezoelectric layers have to be considered. The coupled finite element and boundary element equations are transformed into modal coordinates, which is more convenient for transient excitation. Several transient problems are solved based on this formulation. Two control designs, a linear quadratic regulator (LQR) and a feedforward controller, are applied to reduce the acoustic pressure inside the cavity based on the equations in modal coordinates. The results indicate that both controllers can reduce the interior acoustic pressure and the plate deflection.

  2. Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

    NASA Technical Reports Server (NTRS)

    Zuckerwar, Allan J. (Inventor); Davis, David C. (Inventor)

    1995-01-01

    An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.

  3. Explaining potential antecedents of workplace social support: reciprocity or attractiveness?

    PubMed

    Bowling, Nathan A; Beehr, Terry A; Johnson, Adam L; Semmer, Norbert K; Hendricks, Elizabeth A; Webster, Heather A

    2004-10-01

    Effects of social support are an important topic in occupational stress theories and research, yet little is known about support's potential antecedents. Based on reciprocity theory, the authors hypothesized that the social support received is related to the extent the employee performs organizational citizenship behaviors directed at individuals and to one's social competence; based on the notion of personal attraction, the authors hypothesized that employees' physical attractiveness and sense of humor would be associated with the amount of social support received. In a survey of 123 high school employees and separate ratings of their attractiveness, reciprocity variables were related but attraction variables were not related to social support availability. Further research should examine reciprocity in predicting social support. PMID:15506850

  4. Repeated games and direct reciprocity under active linking

    PubMed Central

    Pacheco, Jorge M.; Traulsen, Arne; Ohtsuki, Hisashi; Nowak, Martin A.

    2008-01-01

    Direct reciprocity relies on repeated encounters between the same two individuals. Here we examine the evolution of cooperation under direct reciprocity in dynamically structured populations. Individuals occupy the vertices of a graph, undergoing repeated interactions with their partners via the edges of the graph. Unlike the traditional approach to evolutionary game theory, where individuals meet at random and have no control over the frequency or duration of interactions, we consider a model in which individuals differ in the rate at which they seek new interactions. Moreover, once a link between two individuals has formed, the productivity of this link is evaluated. Links can be broken off at different rates. Whenever the active dynamics of links is sufficiently fast, population structure leads to a simple transformation of the payoff matrix, effectively changing the game under consideration, and hence paving the way for reciprocators to dominate defectors.We derive analytical conditions for evolutionary stability. PMID:18076911

  5. A multiplexed immunoassay system based upon reciprocating centrifugal microfluidics

    PubMed Central

    Noroozi, Zahra; Kido, Horacio; Peytavi, Régis; Nakajima-Sasaki, Rie; Jasinskas, Algimantas; Micic, Miodrag; Felgner, Philip L.; Madou, Marc J.

    2011-01-01

    A novel, centrifugal disk-based micro-total analysis system (μTAS) for low cost and high throughput semi-automated immunoassay processing was developed. A key innovation in the disposable immunoassay disk design is in a fluidic structure that enables very efficient micro-mixing based on a reciprocating mechanism in which centrifugal acceleration acting upon a liquid element first generates and stores pneumatic energy that is then released by a reduction of the centrifugal acceleration, resulting in a reversal of direction of flow of the liquid. Through an alternating sequence of high and low centrifugal acceleration, the system reciprocates the flow of liquid within the disk to maximize incubation/hybridization efficiency between antibodies and antigen macromolecules during the incubation/hybridization stage of the assay. The described reciprocating mechanism results in a reduction in processing time and reagent consumption by one order of magnitude. PMID:21721711

  6. Spatially correlated heterogeneous aspirations to enhance network reciprocity

    NASA Astrophysics Data System (ADS)

    Tanimoto, Jun; Nakata, Makoto; Hagishima, Aya; Ikegaya, Naoki

    2012-02-01

    Perc & Wang demonstrated that aspiring to be the fittest under conditions of pairwise strategy updating enhances network reciprocity in structured populations playing 2×2 Prisoner's Dilemma games (Z. Wang, M. Perc, Aspiring to the fittest and promoted of cooperation in the Prisoner's Dilemma game, Physical Review E 82 (2010) 021115; M. Perc, Z. Wang, Heterogeneous aspiration promotes cooperation in the Prisoner's Dilemma game, PLOS one 5 (12) (2010) e15117). Through numerical simulations, this paper shows that network reciprocity is even greater if heterogeneous aspirations are imposed. We also suggest why heterogeneous aspiration fosters network reciprocity. It distributes strategy updating speed among agents in a manner that fortifies the initially allocated cooperators' clusters against invasion. This finding prompted us to further enhance the usual heterogeneous aspiration cases for heterogeneous network topologies. We find that a negative correlation between degree and aspiration level does extend cooperation among heterogeneously structured agents.

  7. Means and method of balancing multi-cylinder reciprocating machines

    DOEpatents

    Corey, John A.; Walsh, Michael M.

    1985-01-01

    A virtual balancing axis arrangement is described for multi-cylinder reciprocating piston machines for effectively balancing out imbalanced forces and minimizing residual imbalance moments acting on the crankshaft of such machines without requiring the use of additional parallel-arrayed balancing shafts or complex and expensive gear arrangements. The novel virtual balancing axis arrangement is capable of being designed into multi-cylinder reciprocating piston and crankshaft machines for substantially reducing vibrations induced during operation of such machines with only minimal number of additional component parts. Some of the required component parts may be available from parts already required for operation of auxiliary equipment, such as oil and water pumps used in certain types of reciprocating piston and crankshaft machine so that by appropriate location and dimensioning in accordance with the teachings of the invention, the virtual balancing axis arrangement can be built into the machine at little or no additional cost.

  8. Reciprocal relationships between the oscillatory systems of the brain.

    PubMed

    Knyazev, G G; Slobodskoi-Plyusnin, Ya Yu; Savost'yanov, A N; Levin, E A; Bocharov, A V

    2010-01-01

    Resting EEG recordings were made from cohorts of 146 children aged 7-17 years and 132 adults aged 18-32 years and the levels of personality features and psychopathology were assessed using the Eysenck, Spilberger, Gray-Wilson, and Goodman questionnaires. Factor analysis was used to discriminate covariance of measures of the spectral power of EEG rhythms into positive and negative components. The latter were interpreted as a measure of inhibitory interactions between oscillatory systems. In children, positive covariance of rhythms was stronger than in adults, while reciprocal relationships between oscillatory systems were weaker. In adults, trait anxiety correlated positively with the strength of the reciprocal relationship between the alpha and delta oscillatory systems. In children, an analogous relationship was seen between anxiety and the strength of the reciprocal relationship between the theta and delta systems. The data are discussed in the light of the evolutionary interpretation of EEG rhythms. PMID:20012491

  9. Reciprocal feeding facilitation between above- and below-ground herbivores.

    PubMed

    McKenzie, Scott W; Vanbergen, Adam J; Hails, Rosemary S; Jones, T Hefin; Johnson, Scott N

    2013-10-23

    Interspecific interactions between insect herbivores predominantly involve asymmetric competition. By contrast, facilitation, whereby herbivory by one insect benefits another via induced plant susceptibility, is uncommon. Positive reciprocal interactions between insect herbivores are even rarer. Here, we reveal a novel case of reciprocal feeding facilitation between above-ground aphids (Amphorophora idaei) and root-feeding vine weevil larvae (Otiorhynchus sulcatus), attacking red raspberry (Rubus idaeus). Using two raspberry cultivars with varying resistance to these herbivores, we further demonstrate that feeding facilitation occurred regardless of host plant resistance. This positive reciprocal interaction operates via an, as yet, unreported mechanism. Specifically, the aphid induces compensatory growth, possibly as a prelude to greater resistance/tolerance, whereas the root herbivore causes the plant to abandon this strategy. Both herbivores may ultimately benefit from this facilitative interaction. PMID:23883576

  10. Constructing and deriving reciprocal trigonometric relations: a functional analytic approach.

    PubMed

    Ninness, Chris; Dixon, Mark; Barnes-Holmes, Dermot; Rehfeldt, Ruth Anne; Rumph, Robin; McCuller, Glen; Holland, James; Smith, Ronald; Ninness, Sharon K; McGinty, Jennifer

    2009-01-01

    Participants were pretrained and tested on mutually entailed trigonometric relations and combinatorially entailed relations as they pertained to positive and negative forms of sine, cosine, secant, and cosecant. Experiment 1 focused on training and testing transformations of these mathematical functions in terms of amplitude and frequency followed by tests of novel relations. Experiment 2 addressed training in accordance with frames of coordination (same as) and frames of opposition (reciprocal of) followed by more tests of novel relations. All assessments of derived and novel formula-to-graph relations, including reciprocal functions with diversified amplitude and frequency transformations, indicated that all 4 participants demonstrated substantial improvement in their ability to identify increasingly complex trigonometric formula-to-graph relations pertaining to same as and reciprocal of to establish mathematically complex repertoires. PMID:19949509

  11. CONSTRUCTING AND DERIVING RECIPROCAL TRIGONOMETRIC RELATIONS: A FUNCTIONAL ANALYTIC APPROACH

    PubMed Central

    Ninness, Chris; Dixon, Mark; Barnes-Holmes, Dermot; Rehfeldt, Ruth Anne; Rumph, Robin; McCuller, Glen; Holland, James; Smith, Ronald; Ninness, Sharon K; McGinty, Jennifer

    2009-01-01

    Participants were pretrained and tested on mutually entailed trigonometric relations and combinatorially entailed relations as they pertained to positive and negative forms of sine, cosine, secant, and cosecant. Experiment 1 focused on training and testing transformations of these mathematical functions in terms of amplitude and frequency followed by tests of novel relations. Experiment 2 addressed training in accordance with frames of coordination (same as) and frames of opposition (reciprocal of) followed by more tests of novel relations. All assessments of derived and novel formula-to-graph relations, including reciprocal functions with diversified amplitude and frequency transformations, indicated that all 4 participants demonstrated substantial improvement in their ability to identify increasingly complex trigonometric formula-to-graph relations pertaining to same as and reciprocal of to establish mathematically complex repertoires. PMID:19949509

  12. Chimpanzees trust conspecifics to engage in low-cost reciprocity

    PubMed Central

    Engelmann, Jan M.; Herrmann, Esther; Tomasello, Michael

    2015-01-01

    Many of humans' most important social interactions rely on trust, including most notably among strangers. But little is known about the evolutionary roots of human trust. We presented chimpanzees (Pan troglodytes) with a modified version of the human trust game—trust in reciprocity—in which subjects could opt either to obtain a small but safe reward on their own or else to send a larger reward to a partner and trust her to reciprocate a part of the reward that she could not access herself. In a series of three studies, we found strong evidence that in interacting with a conspecific, chimpanzees show spontaneous trust in a novel context; flexibly adjust their level of trust to the trustworthiness of their partner and develop patterns of trusting reciprocity over time. At least in some contexts then, trust in reciprocity is not unique to humans, but rather has its evolutionary roots in the social interactions of humans' closest primate relatives. PMID:25589606

  13. Measuring acoustic habitats

    PubMed Central

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

    2015-01-01

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

  14. The Harvard Catalyst Common Reciprocal IRB Reliance Agreement

    PubMed Central

    Winkler, Sabune J.; Witte, Elizabeth; Bierer, Barbara E.

    2014-01-01

    Reduction of duplicative Institutional Review Board (IRB) review for multi-institutional studies is a desirable goal to improve IRB efficiency while enhancing human subject protections. Here we describe the Harvard Catalyst Master Reciprocal Common IRB Reliance Agreement (MRA), a system that provides a legal framework for IRB reliance, with the potential to streamline IRB review processes and reduce administrative burden and barriers to collaborative, multi-institutional research. The MRA respects the legal autonomy of the signatory institutions while offering a pathway to eliminate duplicative IRB review when appropriate. The Harvard Catalyst MRA provides a robust and flexible model for reciprocal reliance that is both adaptable and scalable. PMID:25196592

  15. Ubiquity of Benford's law and emergence of the reciprocal distribution

    NASA Astrophysics Data System (ADS)

    Friar, J. L.; Goldman, T.; Pérez-Mercader, J.

    2016-05-01

    We apply the Law of Total Probability to the construction of scale-invariant probability distribution functions (pdf's), and require that probability measures be dimensionless and unitless under a continuous change of scales. If the scale-change distribution function is scale invariant then the constructed distribution will also be scale invariant. Repeated application of this construction on an arbitrary set of (normalizable) pdf's results again in scale-invariant distributions. The invariant function of this procedure is given uniquely by the reciprocal distribution, suggesting a kind of universality. We separately demonstrate that the reciprocal distribution results uniquely from requiring maximum entropy for size-class distributions with uniform bin sizes.

  16. Optimal estimation of undersea acoustic transponder locations

    NASA Technical Reports Server (NTRS)

    Carta, D. G.

    1978-01-01

    Using principles from multilateration and optimal estimation theories an approach is derived for estimating the relative positions of three or more submerged and anchored acoustic transponders. The procedure is not constrained to processing range data collected at special points or on special trajectories. While the data normally collected over transponders and between transponder pairs can be processed, simultaneous ranges from anywhere on the surface to three or more transponders can also be processed. Simulated examples involving four stations in different geometries with different range collection schemes demonstrate the effectiveness of the procedure.

  17. Acoustic emission monitoring system

    DOEpatents

    Romrell, Delwin M.

    1977-07-05

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

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

    ERIC Educational Resources Information Center

    DOELLE, LESLIE L.

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

  19. Acoustic energy shaping

    NASA Technical Reports Server (NTRS)

    Wang, T. G.; Elleman, D. D. (Inventor)

    1977-01-01

    A suspended mass is shaped by melting all or a selected portion of the mass and applying acoustic energy in varying amounts to different portions of the mass. In one technique for forming an optical waveguide slug, a mass of oval section is suspended and only a portion along the middle of the cross-section is heated to a largely fluid consistency. Acoustic energy is applied to opposite edges of the oval mass to press the unheated opposite edge portions together so as to form bulges at the middle of the mass. In another technique for forming a ribbon of silicon for constructing solar cells, a cylindrical thread of silicon is drawn from a molten mass of silicon, and acoustic energy is applied to opposite sides of the molten thread to flatten it into a ribbon.

  20. Passive broadband acoustic thermometry

    NASA Astrophysics Data System (ADS)

    Anosov, A. A.; Belyaev, R. V.; Klin'shov, V. V.; Mansfel'd, A. D.; Subochev, P. V.

    2016-04-01

    The 1D internal (core) temperature profiles for the model object (plasticine) and the human hand are reconstructed using the passive acoustothermometric broadband probing data. Thermal acoustic radiation is detected by a broadband (0.8-3.5 MHz) acoustic radiometer. The temperature distribution is reconstructed using a priori information corresponding to the experimental conditions. The temperature distribution for the heated model object is assumed to be monotonic. For the hand, we assume that the temperature distribution satisfies the heat-conduction equation taking into account the blood flow. The average error of reconstruction determined for plasticine from the results of independent temperature measurements is 0.6 K for a measuring time of 25 s. The reconstructed value of the core temperature of the hand (36°C) generally corresponds to physiological data. The obtained results make it possible to use passive broadband acoustic probing for measuring the core temperatures in medical procedures associated with heating of human organism tissues.

  1. Surface Acoustic Wave Microfluidics

    NASA Astrophysics Data System (ADS)

    Yeo, Leslie Y.; Friend, James R.

    2014-01-01

    Fluid manipulations at the microscale and beyond are powerfully enabled through the use of 10-1,000-MHz acoustic waves. A superior alternative in many cases to other microfluidic actuation techniques, such high-frequency acoustics is almost universally produced by surface acoustic wave devices that employ electromechanical transduction in wafer-scale or thin-film piezoelectric media to generate the kinetic energy needed to transport and manipulate fluids placed in adjacent microfluidic structures. These waves are responsible for a diverse range of complex fluid transport phenomena - from interfacial fluid vibration and drop and confined fluid transport to jetting and atomization - underlying a flourishing research literature spanning fundamental fluid physics to chip-scale engineering applications. We highlight some of this literature to provide the reader with a historical basis, routes for more detailed study, and an impression of the field's future directions.

  2. Latticed pentamode acoustic cloak

    PubMed Central

    Chen, Yi; Liu, Xiaoning; Hu, Gengkai

    2015-01-01

    We report in this work a practical design of pentamode acoustic cloak with microstructure. The proposed cloak is assembled by pentamode lattice made of a single-phase solid material. The function of rerouting acoustic wave round an obstacle has been demonstrated numerically. It is also revealed that shear related resonance due to weak shear resistance in practical pentamode lattices punctures broadband feature predicted based on ideal pentamode cloak. As a consequence, the latticed pentamode cloak can only conceal the obstacle in segmented frequency ranges. We have also shown that the shear resonance can be largely reduced by introducing material damping, and an improved broadband performance can be achieved. These works pave the way for experimental demonstration of pentamode acoustic cloak. PMID:26503821

  3. Seamount acoustic scattering

    NASA Astrophysics Data System (ADS)

    Boehlert, George W.

    The cover of the March 1 issue of Eos showed a time series of acoustic scattering above Southeast Hancock Seamount (29°48‧N, 178°05‧E) on July 17-18, 1984. In a comment on that cover Martin Hovland (Eos, August 2, p. 760) argued that gas or “other far reaching causes” may be involved in the observed acoustic signals. He favors a hypothesis that acoustic scattering observed above a seeping pockmark in the North Sea is a combination of bubbles, stable microbubbles, and pelagic organisms and infers that this may be a more general phenomenon and indeed plays a role in the attraction of organisms to seamounts

  4. A New Wave of Acoustics.

    ERIC Educational Resources Information Center

    Beyer, Robert

    1981-01-01

    Surveys 50 years of acoustical studies by discussing selected topics including the ear, nonlinear representations, underwater sound, acoustical diagnostics, absorption, electrolytes, phonons, magnetic interaction, and superfluidity and the five sounds. (JN)

  5. Propagation of plate acoustic waves in contact with fluid medium

    NASA Astrophysics Data System (ADS)

    Ghatadi Suraji, Nagaraj

    The characteristics of acoustic waves propagating in thin piezoelectric plates in the presence of a fluid medium contacting one or both of the plate surfaces are investigated. If the velocity of plate wave in the substrate is greater than velocity of bulk wave in the fluid, then a plate acoustic wave (PAW) traveling in the substrate will radiate a bulk acoustic wave (BAW) in the fluid. It is found that, under proper conditions, efficient conversion of energy from plate acoustic waves to bulk acoustic waves and vice versa can be obtained. For example, using the fundamental anti symmetric plate wave mode (A0 mode) propagating in a lithium niobate substrate and water as the fluid, total mode conversion loss (PAW to BAW and back from BAW to PAW) of less than 3 dB has been obtained. This mode conversion principle can be used to realize miniature, high efficiency transducers for use in ultrasonic flow meters. Similar type of transducer based on conversion of energy from surface acoustic wave (SAW) to bulk acoustic wave (BAW) has been developed previously. The use of plate waves has several advantages. Since the energy of plate waves is present on both plate surfaces, the inter digital transducer (IDT) can be on the surface opposite from that which is in contact with the fluid. This protects the IDT from possible damage due to the fluid and also simplifies the job of making electrical connections to the IDT. Another advantage is that one has wider choice of substrate materials with plate waves than is the case with SAWs. Preliminary calculations indicate that the mode conversion principle can also be used to generate and detect ultrasonic waves in air. This has potential applications for realizing transducers for use in non-contact ultrasonic's. The design of an ASIC (Application Specific Integrated Circuit) chip containing an amplifier and frequency counter for use with ultrasonic transducers is also presented in this thesis.

  6. 75 FR 80761 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-23

    ... Reciprocating Internal Combustion Engines AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of... air pollutants for reciprocating internal combustion engines and requesting public comment on one.... List of Subjects in 40 CFR Part 63 Administrative practice and procedure, Air pollution...

  7. 77 FR 60341 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-03

    ... Source Performance Standards for Stationary Internal Combustion Engines'' (77 FR 33812). The June 7, 2012... Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion... Emission Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal Combustion Engines...

  8. Elucidations on the Reciprocal Lattice and the Ewald Sphere

    ERIC Educational Resources Information Center

    Foadi, J.; Evans, G.

    2008-01-01

    The reciprocal lattice is derived through the Fourier transform of a generic crystal lattice, as done previously in the literature. A few key derivations are this time handled in detail, and the connection with x-ray diffraction is clearly pointed out. The Ewald sphere is subsequently thoroughly explained and a few comments on its representation…

  9. Self-Esteem and Adolescent Problems: Modeling Reciprocal Effects.

    ERIC Educational Resources Information Center

    Rosenberg, Morris; And Others

    1989-01-01

    Explores the reciprocal relationships between self-esteem and the following three problems of youth: (1) juvenile delinquency; (2) poor school performance; and (3) psychological depression. Findings include the following: (1) low self-esteem fosters delinquency, which may enhance self-esteem; (2) school performance affects self-esteem; and (3)…

  10. Boredom and Academic Achievement: Testing a Model of Reciprocal Causation

    ERIC Educational Resources Information Center

    Pekrun, Reinhard; Hall, Nathan C.; Goetz, Thomas; Perry, Raymond P.

    2014-01-01

    A theoretical model linking boredom and academic achievement is proposed. Based on Pekrun's (2006) control-value theory of achievement emotions, the model posits that boredom and achievement reciprocally influence each other over time. Data from a longitudinal study with college students (N = 424) were used to examine the hypothesized effects. The…

  11. Children's Acquisition of Reciprocal Sentences with Stative and Active Predicates.

    ERIC Educational Resources Information Center

    Matsuo, Ayumi

    2000-01-01

    Shows that children (mean age 4 years and 4 months) not only know the meaning and use of complex reciprocal anaphors like "each other," but that they also have knowledge of subtle differences in the possible interpretations of such anaphors depending on the type of predicates involved. (Author/VWL)

  12. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  13. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  14. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  15. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  16. 47 CFR 97.107 - Reciprocal operating authority.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SERVICES AMATEUR RADIO SERVICE Station Operation Standards § 97.107 Reciprocal operating authority. A non-citizen of the United States (“alien”) holding an amateur service authorization granted by the alien's government is authorized to be the control operator of an amateur station located at places where the...

  17. Longitudinal Study on Reciprocity between Personality Traits and Parenting Stress

    ERIC Educational Resources Information Center

    Rantanen, Johanna; Tillemann, Kati; Metsäpelto, Riitta-Leena; Kokko, Katja; Pulkkinen, Lea

    2015-01-01

    Reciprocal associations between the Big Five personality traits and parenting stress--including both parents' feelings of their distress and perception of their incompetence as parents--were studied with 248 participants (49% of which were males). Longitudinal data, collected at ages 33/36, 42 and 50 years, were used. Cross-lagged path…

  18. Paradoxical Effects of Feedback in International Online Reciprocal Peer Tutoring

    ERIC Educational Resources Information Center

    Topping, K. J.; Dehkinet, R.; Blanch, S.; Corcelles, M.; Duran, D.

    2013-01-01

    This paper reports an online reciprocal peer tutoring project for improving language competence in Spanish and English. Students aged 9-12 years from Scotland and Catalonia were matched to act as tutors in their own language and as tutees in a modern foreign language. Students were intended to improve both their first language (through helping the…

  19. Helper Bank: A Reciprocal Services Program for Older Adults.

    ERIC Educational Resources Information Center

    Goodman, Catherine Chase

    1984-01-01

    Describes a hypothetical program called the Helper Bank, which uses time instead of money as the medium of exchange for services. The reciprocal relationship allows older persons to volunteer to help others as well as provide for future needs such as shopping, transportation or housekeeping. (JAC)

  20. 32 CFR 634.16 - Reciprocal state-military action.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... administration and driver licensing. Statutory authority may exist within some states or host nations for... and direct the installation law enforcement officer to pursue reciprocity with state or host nation... the date that state or host-nation driving privileges are suspended or revoked. This effective...

  1. Magnetic-free non-reciprocity based on staggered commutation

    NASA Astrophysics Data System (ADS)

    Reiskarimian, Negar; Krishnaswamy, Harish

    2016-04-01

    Lorentz reciprocity is a fundamental characteristic of the vast majority of electronic and photonic structures. However, non-reciprocal components such as isolators, circulators and gyrators enable new applications ranging from radio frequencies to optical frequencies, including full-duplex wireless communication and on-chip all-optical information processing. Such components today dominantly rely on the phenomenon of Faraday rotation in magneto-optic materials. However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit. Here we demonstrate magnetic-free linear passive non-reciprocity based on the concept of staggered commutation. Commutation is a form of parametric modulation with very high modulation ratio. We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal-oxide-semiconductor integrated circuit for the first time.

  2. Aging, Neighborhood Attachment, and Fear of Crime: Testing Reciprocal Effects

    ERIC Educational Resources Information Center

    Oh, Joong-Hwan; Kim, Sangmoon

    2009-01-01

    This study attempts to examine the reciprocal effects between fear of crime and neighborhood attachment because aging is a critical factor in both discussions of fear of crime and neighborhood attachment (friendship, neighboring, social cohesion and trust, informal social control, and participation in neighborhood watch program). Using data from…

  3. Reciprocity of Prosocial Behavior in Japanese Preschool Children

    ERIC Educational Resources Information Center

    Fujisawa, Keiko K.; Kutsukake, Nobuyuki; Hasegawa, Toshikazu

    2008-01-01

    This study investigated the reciprocity of prosocial behavior among 3- and 4-year-old Japanese preschool children during free-play time. Matrix correlation tests revealed positive correlations between the frequencies of object offering given and received within dyads and between the frequencies of helping given and received within dyads. These…

  4. Oncogenic KRAS Regulates Tumor Cell Signaling via Stromal Reciprocation

    PubMed Central

    Tape, Christopher J.; Ling, Stephanie; Dimitriadi, Maria; McMahon, Kelly M.; Worboys, Jonathan D.; Leong, Hui Sun; Norrie, Ida C.; Miller, Crispin J.; Poulogiannis, George; Lauffenburger, Douglas A.; Jørgensen, Claus

    2016-01-01

    Summary Oncogenic mutations regulate signaling within both tumor cells and adjacent stromal cells. Here, we show that oncogenic KRAS (KRASG12D) also regulates tumor cell signaling via stromal cells. By combining cell-specific proteome labeling with multivariate phosphoproteomics, we analyzed heterocellular KRASG12D signaling in pancreatic ductal adenocarcinoma (PDA) cells. Tumor cell KRASG12D engages heterotypic fibroblasts, which subsequently instigate reciprocal signaling in the tumor cells. Reciprocal signaling employs additional kinases and doubles the number of regulated signaling nodes from cell-autonomous KRASG12D. Consequently, reciprocal KRASG12D produces a tumor cell phosphoproteome and total proteome that is distinct from cell-autonomous KRASG12D alone. Reciprocal signaling regulates tumor cell proliferation and apoptosis and increases mitochondrial capacity via an IGF1R/AXL-AKT axis. These results demonstrate that oncogene signaling should be viewed as a heterocellular process and that our existing cell-autonomous perspective underrepresents the extent of oncogene signaling in cancer. Video Abstract PMID:27087446

  5. Asymptotic expansions for the reciprocal of the gamma function

    NASA Astrophysics Data System (ADS)

    Withers, Christopher S.; Nadarajah, Saralees

    2014-05-01

    Asymptotic expansions are derived for the reciprocal of the gamma function. We show that the coefficients of the expansion are the same, up to a sign change, as the asymptotic expansions for the gamma function obtained by exponentiating the expansions of its logarithm due to Stirling and de Moivre. Expressions for the coefficients are given in terms of Bell polynomials.

  6. 26 CFR 521.116 - Reciprocal administrative assistance.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 19 2012-04-01 2010-04-01 true Reciprocal administrative assistance. 521.116 Section 521.116 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) REGULATIONS UNDER TAX CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish Corporations...

  7. A rapid, precise, reciprocating-movement color filter system

    NASA Technical Reports Server (NTRS)

    Phillipps, P. G.; Epstein, P.; Donovan, G.; Lawhite, E.

    1972-01-01

    Unit was designed for moving color filters in and out of position in less than 46 ms. System may be used to record previously derived colors on photorecorder or to scan different color or wavelength components of rapidly passing scene, as in aerial reconnaissance. Rapid, precise reciprocating movement may be useful in purely mechanical and chemical applications.

  8. An intergenomic reciprocal translocation associated with oat winterhardiness

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The reciprocal intergenomic translocation between hexaploid oat (Avena sp.) chromosomes 7C and 17 (T7C-17) has been associated with the division of cultivated oat into A. sativa (L.) and A. byzantina (C. Koch) species as well as fall and spring growth habit. The objective of this experiment was to ...

  9. A Reciprocal Peer Review System to Support College Students' Writing

    ERIC Educational Resources Information Center

    Yang, Yu-Fen

    2011-01-01

    As students' problem-solving processes in writing are rarely observed in face-to-face instruction, they have few opportunities to participate collaboratively in peer review to improve their texts. This study reports the design of a reciprocal peer review system for students to observe and learn from each other when writing. A sample of 95…

  10. The Centrality of Reciprocity to Communication and Democracy.

    ERIC Educational Resources Information Center

    Rucinski, Dianne

    1991-01-01

    Focuses on the implications of participatory democratic theory, as compared to elite democratic theory, for political communication theorists. Discusses how reciprocity provides political communication researchers with a tool for gauging the successes of various communication systems in enhancing participatory democracy. Suggests how mass-mediated…

  11. Experienced Teacher Learning within the Context of Reciprocal Peer Coaching

    ERIC Educational Resources Information Center

    Zwart, R. C.; Wubbels, T.; Bergen, T. C. M.; Bolhuis, S.

    2007-01-01

    A considerable amount of literature on peer coaching suggests that the professional development of teachers can be improved through experimentation, observation, reflection, the exchange of professional ideas, and shared problem-solving. Reciprocal peer coaching provides teachers with an opportunity to engage in such activities in an integrated…

  12. A Case Study of Learning Architecture and Reciprocity

    ERIC Educational Resources Information Center

    Smith, Anne B.

    2009-01-01

    This ethnographic case study follows the trajectory of one child's learning disposition, reciprocity, and its relationship to the "learning architecture" of her early childhood and primary school learning environments, over eighteen months. Learning dispositions are coping strategies or habits of mind, and tendencies to respond to and select from…

  13. Magnetic-free non-reciprocity based on staggered commutation.

    PubMed

    Reiskarimian, Negar; Krishnaswamy, Harish

    2016-01-01

    Lorentz reciprocity is a fundamental characteristic of the vast majority of electronic and photonic structures. However, non-reciprocal components such as isolators, circulators and gyrators enable new applications ranging from radio frequencies to optical frequencies, including full-duplex wireless communication and on-chip all-optical information processing. Such components today dominantly rely on the phenomenon of Faraday rotation in magneto-optic materials. However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit. Here we demonstrate magnetic-free linear passive non-reciprocity based on the concept of staggered commutation. Commutation is a form of parametric modulation with very high modulation ratio. We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal-oxide-semiconductor integrated circuit for the first time. PMID:27079524

  14. Reciprocal Relationships between Job Resources, Personal Resources, and Work Engagement

    ERIC Educational Resources Information Center

    Xanthopoulou, Despoina; Bakker, Arnold B.; Demerouti, Evangelia; Schaufeli, Wilmar B.

    2009-01-01

    This study examined longitudinal relationships between job resources, personal resources, and work engagement. On the basis of Conservation of Resources theory, we hypothesized that job resources, personal resources, and work engagement are reciprocal over time. The study was conducted among 163 employees, who were followed-up over a period of 18…

  15. Oncogenic KRAS Regulates Tumor Cell Signaling via Stromal Reciprocation.

    PubMed

    Tape, Christopher J; Ling, Stephanie; Dimitriadi, Maria; McMahon, Kelly M; Worboys, Jonathan D; Leong, Hui Sun; Norrie, Ida C; Miller, Crispin J; Poulogiannis, George; Lauffenburger, Douglas A; Jørgensen, Claus

    2016-05-01

    Oncogenic mutations regulate signaling within both tumor cells and adjacent stromal cells. Here, we show that oncogenic KRAS (KRAS(G12D)) also regulates tumor cell signaling via stromal cells. By combining cell-specific proteome labeling with multivariate phosphoproteomics, we analyzed heterocellular KRAS(G12D) signaling in pancreatic ductal adenocarcinoma (PDA) cells. Tumor cell KRAS(G12D) engages heterotypic fibroblasts, which subsequently instigate reciprocal signaling in the tumor cells. Reciprocal signaling employs additional kinases and doubles the number of regulated signaling nodes from cell-autonomous KRAS(G12D). Consequently, reciprocal KRAS(G12D) produces a tumor cell phosphoproteome and total proteome that is distinct from cell-autonomous KRAS(G12D) alone. Reciprocal signaling regulates tumor cell proliferation and apoptosis and increases mitochondrial capacity via an IGF1R/AXL-AKT axis. These results demonstrate that oncogene signaling should be viewed as a heterocellular process and that our existing cell-autonomous perspective underrepresents the extent of oncogene signaling in cancer. VIDEO ABSTRACT. PMID:27087446

  16. Magnetic-free non-reciprocity based on staggered commutation

    PubMed Central

    Reiskarimian, Negar; Krishnaswamy, Harish

    2016-01-01

    Lorentz reciprocity is a fundamental characteristic of the vast majority of electronic and photonic structures. However, non-reciprocal components such as isolators, circulators and gyrators enable new applications ranging from radio frequencies to optical frequencies, including full-duplex wireless communication and on-chip all-optical information processing. Such components today dominantly rely on the phenomenon of Faraday rotation in magneto-optic materials. However, they are typically bulky, expensive and not suitable for insertion in a conventional integrated circuit. Here we demonstrate magnetic-free linear passive non-reciprocity based on the concept of staggered commutation. Commutation is a form of parametric modulation with very high modulation ratio. We observe that staggered commutation enables time-reversal symmetry breaking within very small dimensions (λ/1,250 × λ/1,250 in our device), resulting in a miniature radio-frequency circulator that exhibits reduced implementation complexity, very low loss, strong non-reciprocity, significantly enhanced linearity and real-time reconfigurability, and is integrated in a conventional complementary metal–oxide–semiconductor integrated circuit for the first time. PMID:27079524

  17. Reciprocal Teaching of Comprehension Strategies Improves EFL Learners' Writing Ability

    ERIC Educational Resources Information Center

    Ghorbani, Mohammad Reza; Gangeraj, Atefeh Ardeshir; Alavi, Sahar Zahed

    2013-01-01

    Although the importance of reading in developing writing ability is undeniable, few competent readers in EFL contexts develop into competent writers. Since students are not aware that reading can assist them in writing, this study examined the effect of reciprocal teaching--which focuses on four reading comprehension strategies, namely…

  18. 14 CFR 440.17 - Reciprocal waiver of claims requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... each of its contractors and subcontractors, each customer and each of the customer's contractors and..., and its customer shall enter into a three-party reciprocal waiver of claims agreement. The three-party... requirements. (d) The licensee or permittee, its customer, and the Federal Aviation Administration of...

  19. Creating Reciprocal Learning Relationships across Socially-Constructed Borders.

    ERIC Educational Resources Information Center

    Skilton-Sylvester, Ellen; Erwin, Eileen K.

    2000-01-01

    Evaluated a service learning course that matched preservice teachers and older adult literacy learners and aimed to address widespread attrition in adult education programs and the need for multicultural education for preservice teachers. Data revealed two essential elements of successful, reciprocal learning relationships: connecting across…

  20. Coaction versus reciprocity in continuous-time models of cooperation.

    PubMed

    van Doorn, G Sander; Riebli, Thomas; Taborsky, Michael

    2014-09-01

    Cooperating animals frequently show closely coordinated behaviours organized by a continuous flow of information between interacting partners. Such real-time coaction is not captured by the iterated prisoner's dilemma and other discrete-time reciprocal cooperation games, which inherently feature a delay in information exchange. Here, we study the evolution of cooperation when individuals can dynamically respond to each other's actions. We develop continuous-time analogues of iterated-game models and describe their dynamics in terms of two variables, the propensity of individuals to initiate cooperation (altruism) and their tendency to mirror their partner's actions (coordination). These components of cooperation stabilize at an evolutionary equilibrium or show oscillations, depending on the chosen payoff parameters. Unlike reciprocal altruism, cooperation by coaction does not require that those willing to initiate cooperation pay in advance for uncertain future benefits. Correspondingly, we show that introducing a delay to information transfer between players is equivalent to increasing the cost of cooperation. Cooperative coaction can therefore evolve much more easily than reciprocal cooperation. When delays entirely prevent coordination, we recover results from the discrete-time alternating prisoner's dilemma, indicating that coaction and reciprocity are connected by a continuum of opportunities for real-time information exchange. PMID:24727186

  1. Reciprocal Teaching of Lecture Comprehension Skills in College Students

    ERIC Educational Resources Information Center

    Spivey, Norman R.; Cuthbert, Andrea

    2006-01-01

    This study explored the effects of a reciprocal teaching intervention designed to enhance the lecture comprehension skills of college students. Forty low-verbal ability students and 40 high-verbal ability students (as measured by SAT scores) were chosen for the study and randomly assigned to experimental or control groups. The experimental groups…

  2. The reciprocal relations between morphological processes and reading.

    PubMed

    Kruk, Richard S; Bergman, Krista

    2013-01-01

    Reciprocal relations between emerging morphological processes and reading skills were examined in a longitudinal study tracking children from Grade 1 through Grade 3. The aim was to examine predictive relationships between productive morphological processing involving composing and decomposing of inflections and derivations, reading ability for pseudoword and word decoding, and word and passage reading comprehension after controlling for initial abilities in reading, morphological processing, phonological awareness, and vocabulary. Reciprocal influences were indicated by predictive relations among initial morphological processes and later reading abilities co-occurring with relationships between initial reading abilities and later morphological processes. Using multilevel modeling, decomposing and composing were found to predict emerging word decoding and word and passage comprehension but not pseudoword decoding. Reading comprehension predicted growth in decomposing. Subsequent regression analyses of model-estimated early linear growth in predictors and later linear growth in outcomes showed that early growth in morphological processes predicted later growth in word decoding and passage comprehension. Although reciprocal relations between emerging morphological processes and reading skills were observed, the different patterns on each side of the reciprocal "coin" indicated that the mechanisms underlying predictive influences are likely different but related to quality of lexical representations. PMID:23123144

  3. Modeling time-lagged reciprocal psychological empowerment-performance relationships.

    PubMed

    Maynard, M Travis; Luciano, Margaret M; D'Innocenzo, Lauren; Mathieu, John E; Dean, Matthew D

    2014-11-01

    Employee psychological empowerment is widely accepted as a means for organizations to compete in increasingly dynamic environments. Previous empirical research and meta-analyses have demonstrated that employee psychological empowerment is positively related to several attitudinal and behavioral outcomes including job performance. While this research positions psychological empowerment as an antecedent influencing such outcomes, a close examination of the literature reveals that this relationship is primarily based on cross-sectional research. Notably, evidence supporting the presumed benefits of empowerment has failed to account for potential reciprocal relationships and endogeneity effects. Accordingly, using a multiwave, time-lagged design, we model reciprocal relationships between psychological empowerment and job performance using a sample of 441 nurses from 5 hospitals. Incorporating temporal effects in a staggered research design and using structural equation modeling techniques, our findings provide support for the conventional positive correlation between empowerment and subsequent performance. Moreover, accounting for the temporal stability of variables over time, we found support for empowerment levels as positive influences on subsequent changes in performance. Finally, we also found support for the reciprocal relationship, as performance levels were shown to relate positively to changes in empowerment over time. Theoretical and practical implications of the reciprocal psychological empowerment-performance relationships are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25111249

  4. Cognitive Mechanisms Reciprocally Transmit Vulnerability between Depressive and Somatic Symptoms

    PubMed Central

    Harding, Kaitlin A.; Murphy, Karly M.

    2015-01-01

    Despite high comorbidity between depressive and somatic symptoms, cognitive mechanisms that transmit vulnerability between symptom clusters are largely unknown. Dampening, positive rumination, and brooding are three cognitive predictors of depression, with rumination theoretically indicated as a transdiagnostic vulnerability through amplifying and diminishing affect in response to events. Specifically, the excess negative affect and lack of positive affect characteristic of depressive symptoms and underlying somatic symptoms may cause and be caused by cognitive responses to events. Therefore, the current study examined whether comorbidity between depressive and somatic symptoms may be explained by the cognitive mechanisms of dampening and positive rumination in response to positive events and brooding in response to negative events among adults (N = 321) across eight weeks of assessment. We hypothesized that greater dampening and brooding would reciprocally predict greater depressive and somatic symptoms, while greater positive rumination would reciprocally predict fewer depressive and somatic symptoms. Mediation analyses in AMOS 22 indicated that dampening and brooding mediated reciprocal pathways between depressive and somatic symptoms, but positive rumination did not. Findings propose dampening and brooding as mechanisms of the reciprocal relationship between depressive and somatic symptoms through diminishing positive affect and amplifying negative affect in response to positive and negative events. PMID:26783455

  5. The Reciprocal Relations between Morphological Processes and Reading

    ERIC Educational Resources Information Center

    Kruk, Richard S.; Bergman, Krista

    2013-01-01

    Reciprocal relations between emerging morphological processes and reading skills were examined in a longitudinal study tracking children from Grade 1 through Grade 3. The aim was to examine predictive relationships between productive morphological processing involving composing and decomposing of inflections and derivations, reading ability for…

  6. 77 FR 9837 - Airworthiness Directives; Lycoming Engines Reciprocating Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-21

    ... published in the Federal Register on September 1, 2011 (76 FR 54397). That NPRM proposed to require removing... Executive Order 12866, (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR...; AD 2012-03-07] RIN 2120-AA64 Airworthiness Directives; Lycoming Engines Reciprocating Engines...

  7. Densitometry By Acoustic Levitation

    NASA Technical Reports Server (NTRS)

    Trinh, Eugene H.

    1989-01-01

    "Static" and "dynamic" methods developed for measuring mass density of acoustically levitated solid particle or liquid drop. "Static" method, unknown density of sample found by comparison with another sample of known density. "Dynamic" method practiced with or without gravitational field. Advantages over conventional density-measuring techniques: sample does not have to make contact with container or other solid surface, size and shape of samples do not affect measurement significantly, sound field does not have to be know in detail, and sample can be smaller than microliter. Detailed knowledge of acoustic field not necessary.

  8. Acoustic tooth cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S. (Inventor)

    1982-01-01

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

  9. Acoustic emission intrusion detector

    DOEpatents

    Carver, Donald W.; Whittaker, Jerry W.

    1980-01-01

    An intrusion detector is provided for detecting a forcible entry into a secured structure while minimizing false alarms. The detector uses a piezoelectric crystal transducer to sense acoustic emissions. The transducer output is amplified by a selectable gain amplifier to control the sensitivity. The rectified output of the amplifier is applied to a Schmitt trigger circuit having a preselected threshold level to provide amplitude discrimination. Timing circuitry is provided which is activated by successive pulses from the Schmitt trigger which lie within a selected time frame for frequency discrimination. Detected signals having proper amplitude and frequency trigger an alarm within the first complete cycle time of a detected acoustical disturbance signal.

  10. Strong acoustic wave action

    NASA Astrophysics Data System (ADS)

    Gokhberg, M. B.

    1983-07-01

    Experiments devoted to acoustic action on the atmosphere-magnetosphere-ionosphere system using ground based strong explosions are reviewed. The propagation of acoustic waves was observed by ground observations over 2000 km in horizontal direction and to an altitude of 200 km. Magnetic variations up to 100 nT were detected by ARIEL-3 satellite near the epicenter of the explosion connected with the formation of strong field aligned currents in the magnetosphere. The enhancement of VLF emission at 800 km altitude is observed.

  11. Acoustic bubble removal method

    NASA Technical Reports Server (NTRS)

    Trinh, E. H.; Elleman, D. D.; Wang, T. G. (Inventor)

    1983-01-01

    A method is described for removing bubbles from a liquid bath such as a bath of molten glass to be used for optical elements. Larger bubbles are first removed by applying acoustic energy resonant to a bath dimension to drive the larger bubbles toward a pressure well where the bubbles can coalesce and then be more easily removed. Thereafter, submillimeter bubbles are removed by applying acoustic energy of frequencies resonant to the small bubbles to oscillate them and thereby stir liquid immediately about the bubbles to facilitate their breakup and absorption into the liquid.

  12. Acoustic and electromagnetic waves

    NASA Astrophysics Data System (ADS)

    Jones, Douglas Samuel

    Theoretical models of EM and acoustic wave propagation are presented in an introductory text intended for intermediate-level science and engineering students. Chapters are devoted to the mathematical representation of acoustic and EM fields, the special theory of relativity, radiation, resonators, waveguide theory, refraction, surface waves, scattering by smooth objects, diffraction by edges, and transient waves. The mathematical tools required for the analysis (Bessel, Legendre, Mathieu, parabolic-cylinder, and spheroidal functions; tensor calculus; and the asymptotic evaluation of integrals) are covered in appendices.

  13. Structural Acoustics and Vibrations

    NASA Astrophysics Data System (ADS)

    Chaigne, Antoine

    This chapter is devoted to vibrations of structures and to their coupling with the acoustic field. Depending on the context, the radiated sound can be judged as desirable, as is mostly the case for musical instruments, or undesirable, like noise generated by machinery. In architectural acoustics, one main goal is to limit the transmission of sound through walls. In the automobile industry, the engineers have to control the noise generated inside and outside the passenger compartment. This can be achieved by means of passive or active damping. In general, there is a strong need for quieter products and better sound quality generated by the structures in our daily environment.

  14. Acoustic loading in straight pipes

    NASA Technical Reports Server (NTRS)

    El-Raheb, M.

    1980-01-01

    Based on linear one-dimensional acoustics, a geometrically perfect elastic waveguide would respond to an oscillatory internal pressure only in the presence of path deflectors (elbows and branches). In practice, a significant elasto-acoustic interaction results even in straight conduits as a result of manufacturing tolerances. A theoretical model of the linear acoustic loading in straight pipes is developed that considers the acoustic wave distortion due to perimeter, axial, and wall thickness nonuniformities.

  15. Spacecraft Internal Acoustic Environment Modeling

    NASA Technical Reports Server (NTRS)

    Allen, Christopher; Chu, S. Reynold

    2008-01-01

    The objective of the project is to develop an acoustic modeling capability, based on commercial off-the-shelf software, to be used as a tool for oversight of the future manned Constellation vehicles to ensure compliance with acoustic requirements and thus provide a safe and habitable acoustic environment for the crews, and to validate developed models via building physical mockups and conducting acoustic measurements.

  16. A surface-acoustic-wave-based cantilever bio-sensor.

    PubMed

    De Simoni, Giorgio; Signore, Giovanni; Agostini, Matteo; Beltram, Fabio; Piazza, Vincenzo

    2015-06-15

    A scalable surface-acoustic-wave- (SAW-) based cantilevered device for portable bio-chemical sensing applications is presented. Even in the current, proof-of-principle implementation this architecture is shown to outperform commercial quartz-crystal microbalances in terms of sensitivity. Adhesion of analytes on a functionalized surface of the cantilever shifts the resonant frequency of a SAW-generating transducer due to the stress-induced variation of the speed of surface acoustic modes. We discuss the relevance of this approach for diagnostics applications based on miniaturized devices. PMID:25643594

  17. Quantum-corrected finite entropy of noncommutative acoustic black holes

    NASA Astrophysics Data System (ADS)

    Anacleto, M. A.; Brito, F. A.; Luna, G. C.; Passos, E.; Spinelly, J.

    2015-11-01

    In this paper we consider the generalized uncertainty principle in the tunneling formalism via Hamilton-Jacobi method to determine the quantum-corrected Hawking temperature and entropy for 2 + 1-dimensional noncommutative acoustic black holes. In our results we obtain an area entropy, a correction logarithmic in leading order, a correction term in subleading order proportional to the radiation temperature associated with the noncommutative acoustic black holes and an extra term that depends on a conserved charge. Thus, as in the gravitational case, there is no need to introduce the ultraviolet cut-off and divergences are eliminated.

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  19. Classroom acoustics in Omaha, Nebraska: Measurements and outreach

    NASA Astrophysics Data System (ADS)

    Bowden, Erica E.; Wang, Lily M.; Bradley, David T.

    2002-11-01

    This project collected data detailing the current status of classroom acoustics while simultaneously increasing awareness of educational acoustics and exposure to acoustical engineering research in local schools. In 8 Omaha-area schools, 2 acoustical aspects which directly influence speech intelligibility were measured and studied: (1) background noise levels resulting from a building's mechanical systems; and (2) reverberation times within the classroom. Prior to each measurement session, a presentation on good classroom acoustic principles was presented to the teacher and students in that classroom. Subsequently, the teacher and students assisted the principal investigator and research assistants in the measurement of the acoustic data from their classroom. In total, 13 classrooms were studied, with the assistance of 425 middle and high school students in 14 different classes. The background noise results have been associated with commonly used noise criterion curves. Results are compared to recommended background noise levels and reverberation times suggested by ANSI standard S12.60-2002. The resulting database provides knowledge on the current status of classrooms in Omaha, and may be indicative of classroom situations across the midwestern United States.

  20. Variable-Position Acoustic Levitation

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Stoneburner, J. D.; Jacobi, N.; Wang, T. G.

    1983-01-01

    Method of acoustic levitation supports objects at positions other than acoustic nodes. Acoustic force is varied so it balances gravitational (or other) force, thereby maintaining object at any position within equilibrium range. Levitation method applicable to containerless processing. Such objects as table-tennis balls, hollow plastic spheres, and balsa-wood spheres levitated in laboratory by new method.

  1. Acoustical Environment of School Buildings.

    ERIC Educational Resources Information Center

    Fitzroy, Dariel; Reid, John L.

    A field study was made of the acoustical environment of schools designed for increased flexibility to meet the spatial requirements of new teaching methods. The object of the study was to define all the criteria for the acoustical design of this type of classroom including the determination of--(1) minimum acoustical separation required for…

  2. ACOUSTICAL ENVIRONMENT OF SCHOOL BUILDINGS.

    ERIC Educational Resources Information Center

    FITZROY, DARIEL; REID, JOHN L.

    A FIELD STUDY WAS MADE OF THE ACOUSTICAL ENVIRONMENT OF SCHOOLS DESIGNED FOR INCREASED FLEXIBILITY TO MEET THE SPATIAL REQUIREMENTS OF NEW TEACHING METHODS. THE OBJECT OF THE STUDY WAS TO DEFINE ALL THE CRITERIA FOR THE ACOUSTICAL DESIGN OF THIS TYPE OF CLASSROOM INCLUDING THE DETERMINATION OF--(1) MINIMUM ACOUSTICAL SEPARATION REQUIRED FOR…

  3. Post Treatment of Acoustic Neuroma

    MedlinePlus

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

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  5. Acoustic subwavelength imaging of subsurface objects with acoustic resonant metalens

    SciTech Connect

    Cheng, Ying; Liu, XiaoJun; Zhou, Chen; Wei, Qi; Wu, DaJian

    2013-11-25

    Early research into acoustic metamaterials has shown the possibility of achieving subwavelength near-field acoustic imaging. However, a major restriction of acoustic metamaterials is that the imaging objects must be placed in close vicinity of the devices. Here, we present an approach for acoustic imaging of subsurface objects far below the diffraction limit. An acoustic metalens made of holey-structured metamaterials is used to magnify evanescent waves, which can rebuild an image at the central plane. Without changing the physical structure of the metalens, our proposed approach can image objects located at certain distances from the input surface, which provides subsurface signatures of the objects with subwavelength spatial resolution.

  6. Basic principles of the Stirling cycle

    NASA Astrophysics Data System (ADS)

    1983-03-01

    The basic principles of the Stirling cycle are outlined. From an elementary theory the general properties of the cycle are derived with a discussion of the most important losses. The performance of the fundamental and ideal (isothermal) cycle are described. The actual cycle, which differs from the ideal one by the occurrence of losses is also described. In the ideal Stirling cycle, the cold is produced by the reversible expansion of a gas. The gas performs a closed cycle, during which it is alternately compressed at ambient temperature in a compression space and expanded at the desired low temperature in an expansion space, thereby reciprocating between these spaces through one connecting duct, wherein a regenerator provides for the heat exchange between the outgoing and the returning gas flow. The problem of how to minimize the total sum of the losses is examined.

  7. Collective cell migration: guidance principles and hierarchies.

    PubMed

    Haeger, Anna; Wolf, Katarina; Zegers, Mirjam M; Friedl, Peter

    2015-09-01

    Collective cell migration results from the establishment and maintenance of collective polarization, mechanocoupling, and cytoskeletal kinetics. The guidance of collective cell migration depends on a reciprocal process between cell-intrinsic multicellular organization with leader-follower cell behavior and results in mechanosensory integration of extracellular guidance cues. Important guidance mechanisms include chemotaxis, haptotaxis, durotaxis, and strain-induced mechanosensing to move cell groups along interfaces and paths of least resistance. Additional guidance mechanisms steering cell groups during specialized conditions comprise electrotaxis and passive drift. To form higher-order cell and tissue structures during morphogenesis and cancer invasion, these guidance principles act in parallel and are integrated for collective adaptation to and shaping of varying tissue environments. We review mechanochemical and electrical inputs and multiparameter signal integration underlying collective guidance, decision making, and outcome. PMID:26137890

  8. Measuring the Kuroshio Current with ocean acoustic tomography.

    PubMed

    Taniguchi, Naokazu; Huang, Chen-Fen; Kaneko, Arata; Liu, Cho-Teng; Howe, Bruce M; Wang, Yu-Huai; Yang, Yih; Lin, Ju; Zhu, Xiao-Hua; Gohda, Noriaki

    2013-10-01

    Ocean current profiling using ocean acoustic tomography (OAT) was conducted in the Kuroshio Current southeast of Taiwan from August 20 to September 15, 2009. Sound pulses were transmitted reciprocally between two acoustic stations placed near the underwater sound channel axis and separated by 48 km. Based on the result of ray simulation, the received signals are divided into multiple ray groups because it is difficult to resolve the ray arrivals for individual rays. The average differential travel times from these ray groups are used to reconstruct the vertical profiles of currents. The currents are estimated with respect to the deepest water layer via two methods: An explicit solution and an inversion with regularization. The strong currents were confined to the upper 200 m and rapidly weakened toward 500 m in depth. Both methods give similar results and are consistent with shipboard acoustic Doppler current profiler results in the upper 150 m. The observed temporal variation demonstrates a similar trend to the prediction from the Hybrid Coordinate Ocean Model. PMID:24116522

  9. Payoff non-linearity sways the effect of mistakes on the evolution of reciprocity.

    PubMed

    Kurokawa, Shun

    2016-09-01

    The existence of cooperation is considered to require explanation, and reciprocity is a potential explanatory mechanism. Animals sometimes fail to cooperate even when they attempt to do so, and a reciprocator has an Achilles' heel: it is vulnerable to error (the interaction between two reciprocators can lead to an endless vendetta.). However, the strategy favored by natural selection is determined also by its interaction with other strategies. The relationship between two reciprocators leading to a collapse of cooperation through error does not straightforwardly imply that mistakes make the conditions under which reciprocity evolves stringent. Hence, mistakes may facilitate the evolution of reciprocity. However, it has been shown through the analysis of the interaction between reciprocators and unconditional defectors that the existence of mistakes makes the conditions for reciprocators stable against invasion by an unconditional defector more stringent, which indicates that mistakes discourage the evolution of reciprocity. However, this result is based on the assumption that the effects of cooperation are additive (payoff is linear), while the game played by real animals does not always display this feature. In such cases, the result may be swayed. In this paper, we remove this assumption, reexamining whether mistakes disturb the evolution of reciprocity. Using the analysis of an evolutionarily stable strategy (ESS), we show that when extra fitness costs are present in cases where mutual cooperation is established, mistakes can facilitate the evolution of reciprocity; whereas, when the effect of cooperation is additive, mistakes always disturb the evolution of reciprocity, as has been shown previously. PMID:27424953

  10. 14 CFR 121.181 - Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... person operating a reciprocating engine powered airplane may take off that airplane at a weight, allowing... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Airplanes: Reciprocating engine-powered: En... OPERATIONS Airplane Performance Operating Limitations § 121.181 Airplanes: Reciprocating engine-powered:...

  11. 14 CFR 135.365 - Large transport category airplanes: Reciprocating engine powered: Weight limitations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... category airplanes: Reciprocating engine powered: Weight limitations. (a) No person may take off a... may take off a reciprocating engine powered large transport category airplane for an airport of... may take off a reciprocating engine powered large transport category airplane at a weight more...

  12. 14 CFR 121.181 - Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplanes: Reciprocating engine-powered: En... OPERATIONS Airplane Performance Operating Limitations § 121.181 Airplanes: Reciprocating engine-powered: En... person operating a reciprocating engine powered airplane may take off that airplane at a weight,...

  13. The Effect of Reciprocal Peer Tutoring and Non-Reciprocal Peer Tutoring on the Performance of Students in College Physics

    ERIC Educational Resources Information Center

    Dioso-Henson, Luzale

    2012-01-01

    Formalised peer-to-peer collaboration and the use of web-enhanced materials that are consistent with course objectives, graded assessments and learning outcomes is well known in educational practice. This study compared the academic gains of college students enrolled in Physics using Reciprocal Peer Tutoring (RPT) with others using non-Reciprocal…

  14. Chemical Principls Exemplified

    ERIC Educational Resources Information Center

    Plumb, Robert C.

    1973-01-01

    Two topics are discussed: (1) Stomach Upset Caused by Aspirin, illustrating principles of acid-base equilibrium and solubility; (2) Physical Chemistry of the Drinking Duck, illustrating principles of phase equilibria and thermodynamics. (DF)

  15. Principles of project management

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The basic principles of project management as practiced by NASA management personnel are presented. These principles are given as ground rules and guidelines to be used in the performance of research, development, construction or operational assignments.

  16. Microfiber interferometric acoustic transducers.

    PubMed

    Wang, Xiuxin; Jin, Long; Li, Jie; Ran, Yang; Guan, Bai-Ou

    2014-04-01

    Acoustic and ultrasonic transducers are key components in biomedical information technology, which has been applied in medical diagnosis, photoacoustic endoscopy and photoacoustic imaging. In this paper, an acoustic transducer based on Fabry-Perot interferometer (FPI) fabricated in a microscaled optical fiber is demonstrated. The transducer is fabricated by forming two wavelength-matched Bragg gratings into the microfiber by means of side illumination with a 193nm excimer laser. When placing the transducer in water, the applied acoustic signal periodically changes the refractive index (RI) of the surrounding liquid and modulates the transmission of the FPI based on the evanescent-field interaction between the liquid and the transmitting light. As a result, the acoustic signal can be constructed with a tunable laser whose output wavelength is located at the slope of the inteferometric fringes. The transducer presents a sensitivity of 10 times higher than the counterparts fabricated in conventional singlemode fibers and has great potential to achieve higher resolution for photoacoustic imaging due to its reduced diameter. PMID:24718189

  17. Intelligent Engine Systems: Acoustics

    NASA Technical Reports Server (NTRS)

    Wojno, John; Martens, Steve; Simpson, Benjamin

    2008-01-01

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

  18. Acoustics in Schools.

    ERIC Educational Resources Information Center

    Singer, Miriam J.

    This paper explores the issues associated with poor acoustics within schools. Additionally, it suggests remedies for existing buildings and those under renovation, as well as concerns for new construction. The paper discusses the effects of unwanted noise on students in terms of physiological, motivational, and cognitive influences. Issues are…

  19. Teaching acoustics online

    NASA Astrophysics Data System (ADS)

    Morrison, Andrew; Rossing, Thomas D.

    2003-10-01

    We teach an introductory course in musical acoustics using a Blackboard. Students in this course can access audio and video materials as well as printed materials on our course website. All homework is submitted online, as are tests and examinations. The students also have the opportunity to use synchronous and asynchronous chat rooms to discuss the course with each other or with the instructors.

  20. Micro acoustic spectrum analyzer

    DOEpatents

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

    2004-11-23

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

  1. COMBUSTION ACOUSTICS DIAGNOSTICS

    EPA Science Inventory

    This is an Exploratory Research Project that was awarded by APPCD for research on developing an acoustic flame condition monitor. It will involve a bench scale experiment of 4-6 weeks duration to record adjacent audible energy of a Bunsen burner. The experiment will require a d...

  2. A unique method to study acoustic transmission through ducts using signal synthesis and averaging of acoustic pulses

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Ramakrishnan, R.; Ahuja, K. K.; Brown, W. H.

    1981-01-01

    An acoustic impulse technique using a loudspeaker driver is developed to measure the acoustic properties of a duct/nozzle system. A signal synthesis method is used to generate a desired single pulse with a flat spectrum. The convolution of the desired signal and the inverse Fourier transform of the reciprocal of the driver's response are then fed to the driver. A signal averaging process eliminates the jet mixing noise from the mixture of jet noise and the internal noise, thereby allowing very low intensity signals to be measured accurately, even for high velocity jets. A theoretical analysis is carried out to predict the incident sound field; this is used to help determine the number and locations of the induct measurement points to account for the contributions due to higher order modes present in the incident tube method. The impulse technique is validated by comparing experimentally determined acoustic characteristics of a duct-nozzle system with similar results obtained by the impedance tube method. Absolute agreement in the comparisons was poor, but the overall shapes of the time histories and spectral distributions were much alike.

  3. Acoustics- Version 1.0

    SciTech Connect

    2012-09-13

    This package contains modules that model acoustic sensors and acoustic sources (hearable) in Umbra. It is typically used to represent hearing in characters within Umbra. Typically, the acoustic sensors detect acoustic sources at a given point; however, it also contains the capability to detect bullet cracks by detecting the sound along the bullet path that is closest to the sensor. A memory module, acoustic memory, represents remembered sounds within a given character. Over time, the sounds are removed, as a character forgets what it has heard.

  4. Acoustics- Version 1.0

    2012-09-13

    This package contains modules that model acoustic sensors and acoustic sources (hearable) in Umbra. It is typically used to represent hearing in characters within Umbra. Typically, the acoustic sensors detect acoustic sources at a given point; however, it also contains the capability to detect bullet cracks by detecting the sound along the bullet path that is closest to the sensor. A memory module, acoustic memory, represents remembered sounds within a given character. Over time, themore » sounds are removed, as a character forgets what it has heard.« less

  5. Principles of Modern Soccer.

    ERIC Educational Resources Information Center

    Beim, George

    This book is written to give a better understanding of the principles of modern soccer to coaches and players. In nine chapters the following elements of the game are covered: (1) the development of systems; (2) the principles of attack; (3) the principles of defense; (4) training games; (5) strategies employed in restarts; (6) physical fitness…

  6. Chemical Principles Exemplified

    ERIC Educational Resources Information Center

    Plumb, Robert C.

    1970-01-01

    This is the first of a new series of brief ancedotes about materials and phenomena which exemplify chemical principles. Examples include (1) the sea-lab experiment illustrating principles of the kinetic theory of gases, (2) snow-making machines illustrating principles of thermodynamics in gas expansions and phase changes, and (3) sunglasses that…

  7. Finite-difference lattice Boltzmann simulation on acoustics-induced particle deposition

    NASA Astrophysics Data System (ADS)

    Fu, Sau-Chung; Yuen, Wai-Tung; Wu, Chili; Chao, Christopher Yu-Hang

    2015-10-01

    Particle manipulation by acoustics has been investigated for many years. By a proper design, particle deposition can be induced by the same principle. The use of acoustics can potentially be developed into an energy-efficient technique for particle removal or filtration system as the pressure drop due to acoustic effects is low and the flow velocity is not necessary to be high. Two nonlinear acoustic effects, acoustic streaming and acoustic radiation pressure, are important. Acoustic streaming introduces vortices and stagnation points on the surface of an air duct and removes the particles by deposition. Acoustic radiation pressure causes particles to form agglomerates and enhances inertial impaction and/or gravitational sedimentation. The objective of this paper is to develop a numerical model to investigate the particle deposition induced by acoustic effects. A three-step approach is adopted and lattice Boltzamnn technique is employed as the numerical method. This is because the lattice Boltzmann equation is hyperbolic and can be solved locally, explicitly, and efficiently on parallel computers. In the first step, the acoustic field and its mean square fluctuation values are calculated. Due to the advantage of the lattice Boltzmann technique, a simple, stable and fast lattice Boltzmann method is proposed and verified. The result of the first step is input into the second step to solve for acoustic streaming. Another finite difference lattice Boltzmann method, which has been validated by a number of flows and benchmark cases in the literature, is used. The third step consists in tracking the particle's motion by a Lagrangian approach where the acoustic radiation pressure is considered. The influence of the acoustics effects on particle deposition is explained. The numerical result matches with an experiment. The model is a useful tool for optimizing the design and helps to further develop the technique.

  8. Seismic transmission operator reciprocity - II: impedance-operator symmetry via elastic lateral modes

    NASA Astrophysics Data System (ADS)

    Thomson, C. J.

    2015-08-01

    The properties of the overburden transmission response are of particular interest for the analysis of reflectivity illumination or blurring in seismic depth imaging. The first step to showing a transmission-operator reciprocity property is to identify the symmetry of the so-called displacement-to-traction operators. The latter are analogous to Dirichlet-to-Neumann operators and they may also be called impedance operators. Their symmetry is deduced here after development of a formal spectral or modal theory of lateral wavefunctions in a laterally heterogeneous generally anisotropic elastic medium. The elastic lateral modes are displacement-traction 6-vectors and they are built from two auxiliary 3-vector lateral-mode bases. These auxiliary modes arise from Hermitian and anti-Hermitian operators, so they have familiar properties such as orthogonality. There is no assumption of down/up symmetry of the elasticity tensor, but basic assumptions are made about the existence and completeness of the elastic modes. A point-symmetry property appears and plays a central role. The 6-vector elastic modes have a symplectic orthogonality property, which facilitates the development of modal expansions for 6-vector functions of the lateral coordinates when completeness is assumed. While the elastic modal theory is consistent with the laterally homogeneous case, numerical work would provide confidence that it is correct in general. An appendix contains an introductory overview of acoustic lateral modes that were studied by other authors, given from the perspective of this new work. A distinction is drawn between unit normalization of scalar auxiliary modes and a separate energy-flux normalization of 2-vector acoustic modes. Neither is crucial to the form of acoustic pressure-to-velocity or impedance operators. This statement carries over to the elastic case for the 3-vector auxiliary- and 6-vector elastic-mode normalizations. The modal theory is used to construct the kernel of the

  9. Indifference of marmosets with prenatal valproate exposure to third-party non-reciprocal interactions with otherwise avoided non-reciprocal individuals.

    PubMed

    Yasue, Miyuki; Nakagami, Akiko; Banno, Taku; Nakagaki, Keiko; Ichinohe, Noritaka; Kawai, Nobuyuki

    2015-10-01

    Autism is characterized by deficits in social interaction and social recognition. Although animal models of autism have demonstrated that model animals engage less in social interaction or attend less to conspecifics than control animals, no animal model has yet replicated the deficit in recognition of complex social interaction as is seen in humans with autism. Here, we show that marmosets discriminated between human actors who reciprocated in social exchanges and those who did not; however, marmosets with foetal exposure to valproic acid (VPA marmosets) did not. In the reciprocal condition, two actors exchanged food equally, while in the non-reciprocal condition, one actor (non-reciprocator) ended up with all food and the other actor with none. After observing these exchanges, the control marmosets avoided receiving food from the non-reciprocator in the non-reciprocal condition. However, the VPA marmosets did not show differential preferences in either condition, suggesting that the VPA marmosets did not discriminate between reciprocal and non-reciprocal interactions. These results indicate that normal marmosets can evaluate social interaction between third-parties, while the VPA marmosets are unable to recognize whether an individual is being reciprocal or not. This test battery can serve as a useful tool to qualify primate models of autism. PMID:26133500

  10. Grooming in mandrills and the time frame of reciprocal partner choice.

    PubMed

    Schino, Gabriele; Pellegrini, Barbara

    2009-10-01

    In this study, we examined the time frame of reciprocal partner choice in the grooming interactions of captive mandrills (Mandrillus sphinx) in order to test the hypothesis that the cognitive limitations of primates constrain the occurrence of reciprocation to short time intervals. In contrast to this hypothesis, mandrills groomed preferentially those individuals that groomed them more even when cases of immediate reciprocation were excluded from the analysis. These results show that mandrills were not limited to reciprocating grooming over short time intervals. It is proposed that a system of emotional bookkeeping may support the ability of primates to reciprocate over long time frames. PMID:19492309

  11. Acoustic Suppression Systems and Related Methods

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R. (Inventor); Kern, Dennis L. (Inventor)

    2013-01-01

    An acoustic suppression system for absorbing and/or scattering acoustic energy comprising a plurality of acoustic targets in a containment is described, the acoustic targets configured to have resonance frequencies allowing the targets to be excited by incoming acoustic waves, the resonance frequencies being adjustable to suppress acoustic energy in a set frequency range. Methods for fabricating and implementing the acoustic suppression system are also provided.

  12. Acoustic spectroscopy: A powerful analytical method for the pharmaceutical field?

    PubMed

    Bonacucina, Giulia; Perinelli, Diego R; Cespi, Marco; Casettari, Luca; Cossi, Riccardo; Blasi, Paolo; Palmieri, Giovanni F

    2016-04-30

    Acoustics is one of the emerging technologies developed to minimize processing, maximize quality and ensure the safety of pharmaceutical, food and chemical products. The operating principle of acoustic spectroscopy is the measurement of the ultrasound pulse intensity and phase after its propagation through a sample. The main goal of this technique is to characterise concentrated colloidal dispersions without dilution, in such a way as to be able to analyse non-transparent and even highly structured systems. This review presents the state of the art of ultrasound-based techniques in pharmaceutical pre-formulation and formulation steps, showing their potential, applicability and limits. It reports in a simplified version the theory behind acoustic spectroscopy, describes the most common equipment on the market, and finally overviews different studies performed on systems and materials used in the pharmaceutical or related fields. PMID:26976503

  13. Echo-acoustic flow affects flight in bats.

    PubMed

    Kugler, Kathrin; Greiter, Wolfgang; Luksch, Harald; Firzlaff, Uwe; Wiegrebe, Lutz

    2016-06-15

    Flying animals need to react fast to rapid changes in their environment. Visually guided animals use optic flow, generated by their movement through structured environments. Nocturnal bats cannot make use of optic flow, but rely mostly on echolocation. Here, we show that bats exploit echo-acoustic flow to negotiate flight through narrow passages. Specifically, bats' flight between lateral structures is significantly affected by the echo-acoustic salience of those structures, independent of their physical distance. This is true even though echolocation, unlike vision, provides explicit distance cues. Moreover, the bats reduced the echolocation sound levels in stronger flow, probably to compensate for the increased summary target strength of the lateral reflectors. However, bats did not reduce flight velocity under stronger echo-acoustic flow. Our results demonstrate that sensory flow is a ubiquitous principle for flight guidance, independent of the fundamentally different peripheral representation of flow across the senses of vision and echolocation. PMID:27045094

  14. Driving Toward Guiding Principles

    PubMed Central

    Buckovich, Suzy A.; Rippen, Helga E.; Rozen, Michael J.

    1999-01-01

    As health care moves from paper to electronic data collection, providing easier access and dissemination of health information, the development of guiding privacy, confidentiality, and security principles is necessary to help balance the protection of patients' privacy interests against appropriate information access. A comparative review and analysis was done, based on a compilation of privacy, confidentiality, and security principles from many sources. Principles derived from ten identified sources were compared with each of the compiled principles to assess support level, uniformity, and inconsistencies. Of 28 compiled principles, 23 were supported by at least 50 percent of the sources. Technology could address at least 12 of the principles. Notable consistencies among the principles could provide a basis for consensus for further legislative and organizational work. It is imperative that all participants in our health care system work actively toward a viable resolution of this information privacy debate. PMID:10094065

  15. Experience sharing, emotional reciprocity, and turn-taking

    PubMed Central

    Stevanovic, Melisa; Peräkylä, Anssi

    2015-01-01

    In this perspective article, we consider the relationship between experience sharing and turn-taking. There is much evidence suggesting that human social interaction is permeated by two temporal organizations: (1) the sequential framework of turn-taking and (2) the concurrent framework of emotional reciprocity. From this perspective, we introduce two alternative hypotheses about how the relationship between experience sharing and turn-taking could be viewed. According to the first hypothesis, the home environment of experience sharing is in the concurrent framework of emotional reciprocity, while the motivation to share experiences is in tension with the sequential framework of turn-taking. According to the second hypothesis, people’s inclination to coordinate their actions in terms of turn-taking is motivated precisely by their propensity to share experiences. We consider theoretical and empirical ideas in favor of both of these hypotheses and discuss their implications for future research. PMID:25926811

  16. A dual reciprocal boundary element formulation for viscous flows

    NASA Technical Reports Server (NTRS)

    Lafe, Olu

    1993-01-01

    The advantages inherent in the boundary element method (BEM) for potential flows are exploited to solve viscous flow problems. The trick is the introduction of a so-called dual reciprocal technique in which the convective terms are represented by a global function whose unknown coefficients are determined by collocation. The approach, which is necessarily iterative, converts the governing partial differential equations into integral equations via the distribution of fictitious sources or dipoles of unknown strength on the boundary. These integral equations consist of two parts. The first is a boundary integral term, whose kernel is the unknown strength of the fictitious sources and the fundamental solution of a convection-free flow problem. The second part is a domain integral term whose kernel is the convective portion of the governing PDEs. The domain integration can be transformed to the boundary by using the dual reciprocal (DR) concept. The resulting formulation is a pure boundary integral computational process.

  17. Social network reciprocity as a phase transition in evolutionary cooperation.

    PubMed

    Floría, L M; Gracia-Lázaro, C; Gómez-Gardeñes, J; Moreno, Y

    2009-02-01

    In evolutionary dynamics the understanding of cooperative phenomena in natural and social systems has been the subject of intense research during decades. We focus attention here on the so-called "lattice reciprocity" mechanisms that enhance evolutionary survival of the cooperative phenotype in the prisoner's dilemma game when the population of Darwinian replicators interact through a fixed network of social contacts. Exact results on a "dipole model" are presented, along with a mean-field analysis as well as results from extensive numerical Monte Carlo simulations. The theoretical framework used is that of standard statistical mechanics of macroscopic systems, but with no energy considerations. We illustrate the power of this perspective on social modeling, by consistently interpreting the onset of lattice reciprocity as a thermodynamical phase transition that, moreover, cannot be captured by a purely mean-field approach. PMID:19391805

  18. Modal Analysis for Connecting Rod of Reciprocating Mud Pump

    NASA Astrophysics Data System (ADS)

    Tong, Zhiwei; Liu, Hao; Zhu, Fengxia

    Modal analysis is an effective method to determine vibration mode shapes and weak parts of the complex mechanical system, its main purpose is to use optimal dynamics design method of mechanical structure system instead of the experience analog method. Reciprocating mud pump is the machine that transport mud or water in the process of drilling, which is an important component of the drilling equipment. In order to improve the performance of reciprocating pump and decrease the failure of the connecting rod caused by vibration during running, a modal analysis method is performed. In this paper, a three-dimensional finite-element model of connecting rod was built to provide analytical frequencies and mode shapes, then the modal distribution and vibration mode shapes for connecting rod were obtained by computing. The results showed the weakness of the connecting rod, which would provide the reference to dynamics analysis and structural optimization for connecting rod in the future.

  19. The valve motion characteristics of a reciprocating pump

    NASA Astrophysics Data System (ADS)

    Pei, Junfeng; He, Chao; Lv, Miaorong; Huang, Xianru; Shen, Kejun; Bi, Kunlei

    2016-01-01

    In previous studies on a reciprocating pump, the state, behavior simulation, or experimental analysis of the valve was seldom reported. In the paper, taking a triplex single-acting reciprocating pump as the research object, we established an experimental system for testing valve disc's motion parameters to directly acquire the valve disc motion parameters (acceleration, velocity, and displacement) under actual conditions. Moreover, testing results were compared with the calculation results obtained according to U. Adolph Theory and Approximation Theory. In Approximation Theory, the valve disc motion was not fully considered, thus leading to the large deviation from the actual situation. Compared with the Approximation Theory, U. Adolph Theory is more suitable for the determination of valve disc motion parameters during different strokes and can explain the jumping and hysteresis phenomena of the valve well. A new pump testing method and an experimental system were proposed to provide a new study approach for valve design theory, disc damage mechanism, and pump failure diagnosis.

  20. Fault detection in reciprocating compressor valves under varying load conditions

    NASA Astrophysics Data System (ADS)

    Pichler, Kurt; Lughofer, Edwin; Pichler, Markus; Buchegger, Thomas; Klement, Erich Peter; Huschenbett, Matthias

    2016-03-01

    This paper presents a novel approach for detecting cracked or broken reciprocating compressor valves under varying load conditions. The main idea is that the time frequency representation of vibration measurement data will show typical patterns depending on the fault state. The problem is to detect these patterns reliably. For the detection task, we make a detour via the two dimensional autocorrelation. The autocorrelation emphasizes the patterns and reduces noise effects. This makes it easier to define appropriate features. After feature extraction, classification is done using logistic regression and support vector machines. The method's performance is validated by analyzing real world measurement data. The results will show a very high detection accuracy while keeping the false alarm rates at a very low level for different compressor loads, thus achieving a load-independent method. The proposed approach is, to our best knowledge, the first automated method for reciprocating compressor valve fault detection that can handle varying load conditions.

  1. Experimental verification of reciprocity relations in quantum thermoelectric transport

    NASA Astrophysics Data System (ADS)

    Matthews, J.; Battista, F.; Sánchez, D.; Samuelsson, P.; Linke, H.

    2014-10-01

    Fundamental symmetries in thermoelectric quantum transport, beyond Onsagers relations, were predicted two decades ago but have to date not been observed in experiments. Recent works have predicted the symmetries to be sensitive to energy-dependent, inelastic scattering, raising the question whether they exist in practice. Here, we answer this question affirmatively by experimentally verifying the thermoelectric reciprocity relations in a four-terminal mesoscopic device where each terminal can be electrically and thermally biased individually. The linear-response thermoelectric coefficients are found to be symmetric under simultaneous reversal of magnetic field and exchange of injection and emission contacts. We also demonstrate a controllable breakdown of the reciprocity relations by increasing thermal bias, putting in prospect enhanced thermoelectric performance.

  2. Dynamic study of piping systems for reciprocating compressors

    SciTech Connect

    Wakabayashi, A.; Arai, S.; Yamada, S.

    1995-12-01

    Recently the authors have developed the direct method to study vibration of piping systems for reciprocating compressors, based on the requirement by API-618 Design Approach-3. They have examined the reliability of this direct method by some experiments with a test piping system, by pressure pulsation and nodal vibration measurements. Overall pressure pulsation amplitude and its frequency components at each measurement point were proved.to agree with the results by digital analysis. Close evaluation of ``pipe-supports` stiffness``, as well as boundary conditions, was confirmed to be a necessary condition to proceed the dynamic analysis of the piping system in relation to the pressure pulsation Generated by the reciprocating compressor, which affected the accuracy of final estimation of nodal displacement distribution of the piping system. Field data evaluation is also discussed in this paper.

  3. Ubiquity of Benford's law and emergence of the reciprocal distribution

    DOE PAGESBeta

    Friar, James Lewis; Goldman, Terrance J.; Pérez-Mercader, J.

    2016-04-07

    In this paper, we apply the Law of Total Probability to the construction of scale-invariant probability distribution functions (pdf's), and require that probability measures be dimensionless and unitless under a continuous change of scales. If the scale-change distribution function is scale invariant then the constructed distribution will also be scale invariant. Repeated application of this construction on an arbitrary set of (normalizable) pdf's results again in scale-invariant distributions. The invariant function of this procedure is given uniquely by the reciprocal distribution, suggesting a kind of universality. Finally, we separately demonstrate that the reciprocal distribution results uniquely from requiring maximum entropymore » for size-class distributions with uniform bin sizes.« less

  4. Overview of hydro-acoustic current-measurement applications by the U.S. geological survey in Indiana

    USGS Publications Warehouse

    Morlock, Scott E.; Stewart, James A.

    1999-01-01

    The U.S. Geological Survey (USGS) maintains a network of 170 streamflow-gaging stations in Indiana to collect data from which continuous records of river discharges are produced. Traditionally, the discharge record from a station is produced by recording river stage and making periodic discharge measurements through a range of stage, then developing a relation between stage and discharge. Techniques that promise to increase data collection accuracy and efficiency include the use of hydro-acoustic instrumentation to measure river velocities. The velocity measurements are used to compute river discharge. In-situ applications of hydro-acoustic instruments by the USGS in Indiana include acoustic velocity meters (AVM's) at six streamflow-gaging stations and newly developed Doppler velocity meters (DVM's) at two stations. AVM's use reciprocal travel times of acoustic signals to measure average water velocities along acoustic paths, whereas DVM's use the Doppler shift of backscattered acoustic signals to compute water velocities. In addition to the in-situ applications, three acoustic Doppler current profilers (ADCP's) are used to make river-discharge measurements from moving boats at streamflow-gaging stations in Indiana. The USGS has designed and is testing an innovative unmanned platform from which to make ADCP discharge measurements.

  5. 12th Anglo-French Physical Acoustics Conference (AFPAC2013)

    NASA Astrophysics Data System (ADS)

    2014-04-01

    The Anglo-French Physical Acoustics Conference (AFPAC) had its 12th annual meeting in Villa Clythia, Fréjus, France, from 16th to 18th January 2013. This series of meetings is a collaboration between the Physical Acoustics Group (PAG) of the Institute of Physics and the Groupe d'Acoustique Physique, Sous-marine et UltraSonore (GAPSUS) of the Société Française d'Acoustique. This year, attendees got the opportunity to see the French Riviera with its Mediterranean vegetation covered by a nice thick snow layer. The participants heard 34 excellent oral presentations and saw 3 posters covering an exciting and diverse range of subjects and of frequencies, from ultrasonic wave propagation in chocolate to metamaterials applied to seismic waves for protecting buildings. Among them, invited talks were given by Pr F A Duck ( Enhanced healing by ultrasound: clinical effects and mechanisms), Pr. J-C Valiére, who actually gave two invited talks ( 1. Measurement of audible acoustic particle velocity using laser: Principles, signal processing and applications, 2. Acoustic pots in ancient and medieval buildings: Literary analysis of ancient texts and comparison with recent observations in French churches), Dr P Huthwaite ( Ultrasonic imaging through the resolution of inverse problems), Dr X Lurton ( Underwater acoustic systems on oceanographic research vessels: principles and applications), Dr S Guenneau ( From platonics to seismic metamaterials). For the fifth consecutive year AFPAC is followed by the publication of its proceedings with 12 peer-reviewed papers which cover the most recent research developments in the field of Physical Acoustics in the UK and France. Alain Lhémery (CEA, France) and Nader Saffari (UCL, United Kingdom) French Riviera 12th AFPAC — Villa Clythia, Fréjus (French Riviera), the 17th of January 2013

  6. Degree and reciprocity of self-disclosure in online forums.

    PubMed

    Barak, Azy; Gluck-Ofri, Orit

    2007-06-01

    Cyberspace has become a common social environment in which people interact and operate in many ways. The purpose of the present study was to investigate the occurrence and reciprocity of self-disclosure, two subjects that are extensively studied in face-to-face interactions but only to a limited degree in virtual, computer-mediated, textual communication. Data was based on 240 first messages in a thread, sampled in equal numbers from six Internet forums (three discussion and three support groups), and written in equal numbers by each gender, and 240 first responses to them (a total of 480 forum messages). Trained, expert judges blindly rated each message on the degree to which it disclosed personal information, thoughts, and feelings. Linguistic parameters (total number of words and number of first-voice words) were also used as dependent variables. Results showed the following: (a) self-disclosure in support forums was much higher than in discussion forums, in terms of both total number and type of disclosure; (b) messages in support forums were longer and included more first-voice words than in discussion forums; (c) there were no gender differences interacting with level of self-disclosure; (d) reciprocity of self-disclosure was evident, yielding positive correlations between the measures of self-disclosure in messages and responses to them; (e) some differences appeared in level of reciprocity of self-disclosure between male and female participants, with female respondents tending to be more reciprocal than male respondents. The implications of these results are discussed in light of growing social interactions online, and possible applications are suggested. PMID:17594265

  7. Self-Centering Reciprocating-Permanent-Magnet Machine

    NASA Technical Reports Server (NTRS)

    Bhate, Suresh; Vitale, Nick

    1988-01-01

    New design for monocoil reciprocating-permanent-magnet electric machine provides self-centering force. Linear permanent-magnet electrical motor includes outer stator, inner stator, and permanent-magnet plunger oscillateing axially between extreme left and right positions. Magnets arranged to produce centering force and allows use of only one coil of arbitrary axial length. Axial length of coil chosen to provide required efficiency and power output.

  8. Perceived social position and health: Is there a reciprocal relationship?

    PubMed

    Garbarski, Dana

    2010-03-01

    Recent work exploring the relationship between socioeconomic status and health has employed a psychosocial concept called perceived social position as a predictor of health. Perceived social position is likely the "cognitive averaging" (Singh-Manoux, Marmot, & Adler, 2005) of socioeconomic characteristics over time and, like other socioeconomic factors, is subject to interplay with health over the life course. Based on the hypothesis that health can also affect perceived social position, in this paper we used structural equation modeling to examine whether perceived social position and three different health outcomes were reciprocally related in the Wisconsin Longitudinal Study, a longitudinal cohort study of older adults in the United States. The relationship between perceived social position and health differed across health outcomes-self-reported health, the Health Utilities Index, and depressive symptoms-as well as across operationalization of perceived social position-compared to the population of the United States, compared to one's community, and a latent variable of which the two items are indicators. We found that perceived social position affected self-reported health when operationalized as latent and US perceived social position, yet there was a reciprocal relationship between self-reported health and community perceived social position. There was a reciprocal relationship between perceived social position and the Health Utilities Index, and depressive symptoms affected perceived social position for all operationalization of perceived social position. The findings suggest that the causal relationship hypothesized in prior studies--that perceived social position affects health--does not necessarily hold in empirical models of reciprocal relationships. Future research should interrogate the relationship between perceived social position and health rather than assume the direction of causality in their relationship. PMID:20006415

  9. Tandem Language Learning by E-Mail: Some Basic Principles and a Case Study. CLCS Occasional Paper No. 54.

    ERIC Educational Resources Information Center

    Appel, Marie Christine

    A study investigated the effectiveness of tandem second language learning using electronic mail (e-mail). Tandem language learning refers to a partnership between two learners, each learning the other's native language. The underlying principles of reciprocity and learner autonomy are explored, use of asynchronous communication between individuals…

  10. Education in acoustics in Argentina

    NASA Astrophysics Data System (ADS)

    Miyara, Federico

    2002-11-01

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

  11. Acoustics Discipline Overview

    NASA Technical Reports Server (NTRS)

    Envia, Edmane; Thomas, Russell

    2007-01-01

    As part of the Fundamental Aeronautics Program Annual Review, a summary of the progress made in 2007 in acoustics research under the Subsonic Fixed Wing project is given. The presentation describes highlights from in-house and external activities including partnerships and NRA-funded research with industry and academia. Brief progress reports from all acoustics Phase 1 NRAs are also included as are outlines of the planned activities for 2008 and all Phase 2 NRAs. N+1 and N+2 technology paths outlined for Subsonic Fixed Wing noise targets. NRA Round 1 progressing with focus on prediction method advancement. NRA Round 2 initiating work focused on N+2 technology, prediction methods, and validation. Excellent partnerships in progress supporting N+1 technology targets and providing key data sets.

  12. Radiosurgery of acoustic neurinomas

    SciTech Connect

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

    1991-01-15

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

  13. Acoustic tractor beam.

    PubMed

    Démoré, Christine E M; Dahl, Patrick M; Yang, Zhengyi; Glynne-Jones, Peter; Melzer, Andreas; Cochran, Sandy; MacDonald, Michael P; Spalding, Gabriel C

    2014-05-01

    Negative radiation forces act opposite to the direction of propagation, or net momentum, of a beam but have previously been challenging to definitively demonstrate. We report an experimental acoustic tractor beam generated by an ultrasonic array operating on macroscopic targets (>1 cm) to demonstrate the negative radiation forces and to map out regimes over which they dominate, which we compare to simulations. The result and the geometrically simple configuration show that the effect is due to nonconservative forces, produced by redirection of a momentum flux from the angled sides of a target and not by conservative forces from a potential energy gradient. Use of a simple acoustic setup provides an easily understood illustration of the negative radiation pressure concept for tractor beams and demonstrates continuous attraction towards the source, against a net momentum flux in the system. PMID:24836252

  14. Acoustic Tractor Beam

    NASA Astrophysics Data System (ADS)

    Démoré, Christine E. M.; Dahl, Patrick M.; Yang, Zhengyi; Glynne-Jones, Peter; Melzer, Andreas; Cochran, Sandy; MacDonald, Michael P.; Spalding, Gabriel C.

    2014-05-01

    Negative radiation forces act opposite to the direction of propagation, or net momentum, of a beam but have previously been challenging to definitively demonstrate. We report an experimental acoustic tractor beam generated by an ultrasonic array operating on macroscopic targets (>1 cm) to demonstrate the negative radiation forces and to map out regimes over which they dominate, which we compare to simulations. The result and the geometrically simple configuration show that the effect is due to nonconservative forces, produced by redirection of a momentum flux from the angled sides of a target and not by conservative forces from a potential energy gradient. Use of a simple acoustic setup provides an easily understood illustration of the negative radiation pressure concept for tractor beams and demonstrates continuous attraction towards the source, against a net momentum flux in the system.

  15. Alaskan river environmental acoustics

    NASA Astrophysics Data System (ADS)

    Dahl, Peter H.; Pfisterer, Carl; Geiger, Harold J.

    2005-04-01

    Sonars are used by the Alaska Department of Fish and Game (ADF&G) to obtain daily and hourly estimates of at least four species of migratory salmon during their seasonal migration which lasts from June to beginning of September. Suspended sediments associated with a river's sediment load is an important issue for ADF&G's sonar operations. Acoustically, the suspended sediments are a source of both volume reverberation and excess attenuation beyond that expected in fresh water. Each can impact daily protocols for fish enumeration via sonar. In this talk, results from an environmental acoustic study conducted in the Kenai River (June 1999) using 420 kHz and 200 kHz side looking sonars, and in the Yukon River (July 2001) using a 120 kHz side looking sonar, are discussed. Estimates of the volume scattering coefficient and attenuation are related to total suspended sediments. The relative impact of bubble scattering and sediment scattering is also discussed.

  16. Structural Acoustics and Vibrations

    NASA Astrophysics Data System (ADS)

    Chaigne, Antoine

    This structural chapter is devoted to vibrations of structures and to their coupling with the acoustic field. Depending on the context, the radiated sound can be judged as desirable, as is mostly the case for musical instruments, or undesirable, like noise generated by machinery. In architectural acoustics, one main goal is to limit the transmission of sound through walls. In the automobile industry, the engineers have to control the noise generated inside and outside the passenger compartment. This can be achieved by means of passive or active damping. In general, there is a strong need for quieter products and better sound quality generated by the structures in our daily environment.

  17. A Martian acoustic anemometer.

    PubMed

    Banfield, Don; Schindel, David W; Tarr, Steve; Dissly, Richard W

    2016-08-01

    An acoustic anemometer for use on Mars has been developed. To understand the processes that control the interaction between surface and atmosphere on Mars, not only the mean winds, but also the turbulent boundary layer, the fluxes of momentum, heat and molecular constituents between surface and atmosphere must be measured. Terrestrially this is done with acoustic anemometers, but the low density atmosphere on Mars makes it challenging to adapt such an instrument for use on Mars. This has been achieved using capacitive transducers and pulse compression, and was successfully demonstrated on a stratospheric balloon (simulating the Martian environment) and in a dedicated Mars Wind Tunnel facility. This instrument achieves a measurement accuracy of ∼5 cm/s with an update rate of >20 Hz under Martian conditions. PMID:27586767

  18. Books on acoustics

    NASA Astrophysics Data System (ADS)

    Shaw, Neil A.

    2001-05-01

    The legacy of a man is not limited to just his projects. His writings in many cases are a more lasting, and a definitely more accessible, monument. For 60 years, Leo L. Beranek has produced books on acoustics, acoustic measurements, sound control, music and architecture, noise and vibration control, concert halls, and opera houses in addition to teaching and consulting. His books are standard references and still cited in other books and in technical and professional articles. Many of his books were among, if not, the first comprehensive modern treatment of the subject and many are still foremost. A review of Dr. Beranek's many books as well as some anecdotes about the circumstances and consequences of same will be presented.

  19. A surface-scattering model satisfying energy conservation and reciprocity

    NASA Astrophysics Data System (ADS)

    Sasihithlu, Karthik; Dahan, Nir; Hugonin, Jean-Paul; Greffet, Jean-Jacques

    2016-03-01

    Roughness scattering models based on Kirchhoff's approximation or perturbation theory give a good account of the angular distribution of the scattered intensity but do not satisfy energy conservation and reciprocity rigorously. For applications such as solar cells with rough interfaces producing a quasi isotropic intensity in the multiple scattering regime, an accurate model of the angular pattern is not required. Instead, energy conservation and reciprocity must be satisfied with great accuracy. Here we present a surface scattering model based on analysis of scattering from a layer of particles on top of a substrate in the dipole approximation which satisfies both energy conservation and reciprocity and is thus accurate in all frequency ranges. The model takes into account the absorption in the substrate induced by the particles but does not take into account the near-field interactions between the particles. In arriving at this model, we use the effective-medium approach to show how we can proceed from modeling the electromagnetic scattering from a single particle to modeling the scattering from a layer of particles positioned above a substrate, and finally relate this to the bidirectional scattering distribution function of the substrate.

  20. Swimming by reciprocal motion at low Reynolds number

    PubMed Central

    Qiu, Tian; Lee, Tung-Chun; Mark, Andrew G.; Morozov, Konstantin I.; Münster, Raphael; Mierka, Otto; Turek, Stefan; Leshansky, Alexander M.; Fischer, Peer

    2014-01-01

    Biological microorganisms swim with flagella and cilia that execute nonreciprocal motions for low Reynolds number (Re) propulsion in viscous fluids. This symmetry requirement is a consequence of Purcell’s scallop theorem, which complicates the actuation scheme needed by microswimmers. However, most biomedically important fluids are non-Newtonian where the scallop theorem no longer holds. It should therefore be possible to realize a microswimmer that moves with reciprocal periodic body-shape changes in non-Newtonian fluids. Here we report a symmetric ‘micro-scallop’, a single-hinge microswimmer that can propel in shear thickening and shear thinning (non-Newtonian) fluids by reciprocal motion at low Re. Excellent agreement between our measurements and both numerical and analytical theoretical predictions indicates that the net propulsion is caused by modulation of the fluid viscosity upon varying the shear rate. This reciprocal swimming mechanism opens new possibilities in designing biomedical microdevices that can propel by a simple actuation scheme in non-Newtonian biological fluids. PMID:25369018